Repositório Institucional da Universidade Estadual da Paraíba
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Resolution of overlapping optical signals: Dual sensing vs chemometrics
No full textSignal overlapping is a common issue that often prevents the full implementation of UV–Vis dip probes in on-site analysis, even in the case of relatively simple chemical systems. In this work, two strategies for the resolution of optical signals without the need of sample treatment are compared: (i) dual sensing based on the combination of optical and electrochemical signals; and (ii) data treatment of optical signal by means of chemometrics. For this purpose, two different systems were evaluated. The first one comprised pyrocatechol (CC) and isonicotinamide (INAM) as an example of a system containing only one electroactive species and the second one contained CC and isoniazide (INH) as an example of a chemical system with two electroactive compounds. Both strategies proved successful in the resolution of the optical overlapping in static conditions (i.e., non-stirred solutions), with slopes in the range of 0.88–1.08 and R2 values higher than 0.989 for the representation of predicted vs expected concentration values for both chemical systems. Nevertheless, only chemometrics was able to resolve both systems in dynamic conditions (slopes in the range of 0.873–1.10 and R2 values higher than 0.99), as the increased transport of INH significantly affected electrochemical measurements. Dual sensing was also successful in the resolution of CC and INAM (slopes in the range of 1.014–1.035 and R2 values higher than 0.99), proving even better than chemometric analysis, particularly in the region of lower CC concentrations
Educational experience on modelling for Panamanian mathematics teachers
No full textA nivel internacional, la modelización matemática ha ido ganando un espacio importante en los currículos educativos, razón por la cual la enseñanza de este proceso ha sido incluida en los programas de formación de profesores de matemática. Dada esta importancia, este estudio reporta una experiencia educativa sobre modelización para profesores de matemática de educación secundaria en servicio del sistema escolar panameño, cuyo objetivo es analizar los procedimientos de resolución de estos profesores a problemas de modelización y clasificar dichas resoluciones. El contexto es el Diplomado en Educación Matemática Aplicada a Secundaria, impartido por la Universidad de Panamá, el cual incluyó un submódulo sobre modelización. El "ciclo de modelización desde una perspectiva cognitiva" que se impartió en el submódulo, se utilizó para analizar los procedimientos de resolución a tres problemas planteados a los profesores participantes, mediante las producciones escritas que cargaron a la plataforma virtual del diplomado. Se pudieron identificar cuatro procedimientos de resolución en las 40 producciones analizadas, que fluctuaban desde no comprender totalmente el enunciado de los problemas hasta desarrollar un ciclo completo de modelización. Con estos resultados, se pretende aportar una primera visión general sobre la enseñanza y el aprendizaje de la modelización en el contexto panameño, y sentar las bases para posibles adaptaciones curriculares a la enseñanza de la matemática
Emerging food relationships between social gardens and food banks: An ethnographic approach to the provision of fresh food in the District of Horta-Guinardó, Barcelona
No full textEste artículo se propone como una contribución al debate acerca de los cambios en la garantía alimentaria, a través de una aproximación etnográfica sobre nuevas prácticas de inclusión de alimentos frescos de un huerto social a los bancos de alimentos en el distrito de Horta-Guinardó, Barcelona. Se analiza cómo estas prácticas buscan asegurar el acceso a alimentos locales y de temporada para quienes asisten a los bancos de alimentos y, al mismo tiempo, promueven los huertos sociales como espacios de socialización y producción. Esta preocupación surge en un contexto de continuo deterioro de las condiciones de vida y de críticas a las respuestas asistencialistas tradicionales, que coincide con las reformas en la normativa europea y nacional para las ayudas alimentarias. Específicamente se exploran las dificultades y las posibilidades de transformar las prácticas asistenciales, a través de un análisis etnográfico colaborativo y comprometido, construido a partir de observación participante, encuentros con los diferentes agentes, entrevistas y cuestionarios individuales a los participantes en el huerto social y a las personas que reciben donaciones de bancos de alimentos Los resultados destacan los esfuerzos de articulación entre huertos y bancos de alimentos y el efecto de esta ayuda en el bienestar de las personas. A modo de conclusión se sugiere la importancia de transitar hacia un sistema de garantía alimentaria local, que integre prácticas alternativas, una mayor participación ciudadana y un enfoque holístico de la alimentación. Para lo cual es relevante dar continuidad a las investigaciones sobre las nuevas articulaciones entre diferentes tipos de experiencias.
Calibrating lower‑middle Miocene mammal faunas and unravelling climate change during the Miocene Climate Optimum: the Bardenas Reales de Navarra record (Ebro basin, NE Iberian Peninsula).
No full textThe chronology of lower Miocene Iberian small mammal faunas is still poorly constrained given the scarcity of well dated sedimentary successions including small mammal fossil localities. Such scarcity has prevented also an accurate understanding of the response of European terrestrial ecosystem to global changes across the Miocene climate optimum (MCO), one of the best analogues of present-day global warming. Here we present an updated fossil small mammal record of the Bardenas Reales de Navarra (western Ebro basin, Spain), where an expanded lower to middle Miocene continental succession is superbly exposed. Previous and new magnetostratigraphic results from this succession have enabled us to propose, along with additional magnetostratigraphically-dated Iberian faunas, a new chronology for local zones Y to D (Mammal Neogene zones MN2 to MN5). In addition to that, the studied small mammal faunas point to a gradual increase in temperature and humidity conditions in SW Europe between 20 and 15.5 Ma, which appears to be coupled with the progressive shift towards warmer regional (Atlantic) and global conditions across the MCO, thereby pointing to gradual changes in oceanic circulation as the main driver of this period of global warmth. The evolution of sedimentary facies appears to indicate a threshold response of the Ebro basin hydrological balance to the MCO, whereas pedogenic formation of magnetic minerals seems to be linked to periods of enhanced climate variability. These results highlight the need of combining different paleoenvironmental indicators in order to obtain a reliable view of the response of continental ecosystems to global warming
The Galactic potential effects on the Solar System’s minor bodies
No full textTreballs Finals de Grau de Física, Facultat de Física, Universitat de Barcelona, Curs: 2026, Tutora: Mercè RomeroThis project studies the influence of the Milky Way’s galactic gravitational potential on the orbital evolution of distant Solar System minor objects. Using orbital data from Gaia Data Release 3, minor body motion is modeled through the Circular Restricted Three-Body Problem (Sun–Jupiter–minor body), with Galactic perturbations included as an external force. Two Galactic models are considered: the axisymmetric MWPotential2014 and a non-axisymmetric Spiral Arms plus MWPotential2014, both implemented with the galpy library. Numerical integrations are used to analyze secular variations of orbital elements over long timescales. The study focuses on the dwarf planet Eris and a hypothetical Sun-bound asteroid with a semi-major axis of 530 AU.
Although galactic forces are much weaker than Solar System forces near the Sun, they produce measurable effects at large heliocentric distances: spiral arm effects are negligible near 100 AU, while both galactic components significantly influence orbital stability beyond 500 AU, with the spiral arm pitch angle playing a key rol
Soledad en Personas Mayores Mapuche Urbanas en Chile: Afirmación de la Identidad Étnica, Autonomía y Bienestar Subjetivo como predictores
No full textThis study seeks to identify the factors that predict loneliness among urban Mapuche older adults in Chile. Using a cross-sectional, non-experimental design with a correlational scope, the study included 323 participants, with a mean age of 70.77 years. The findings indicate that a strong affirmation of ethnic identity affirmation, greater autonomy, higher levels of subjective well-being, and a larger number of cohabitants are associated with reduced levels of loneliness. In contrast, gender and age were not significant predictors. These results are important for developing public policies and intervention programs aimed at the urban Mapuche older adult population. Emphasizing the roles of ethnic identity, autonomy, subjective well-being, and the structural characteristics of social networks as key variables can help address loneliness in this demographic. Moreover, the study contributes to a better understanding of the dynamics of loneliness among urban indigenous populations, a group that has been underrepresented in research
Environment-responsive Pt(II) complexes boost aggregation-enhanced emission and singlet oxygen production
No full textHere, we introduce an environment-tuning strategy to simultaneously boost aggregation-enhanced emission (AEE) and singlet oxygen (1O2) generation in PEGylated platinum(II) pyridyl complexes. Different amphiphilic Pt(II) species bearing triazole/tetrazole NˆNˆN ligands self-assemble in response to solvent polarity, polymer confinement, and packing forces, enabling precise control over intermolecular Pt···Pt and π···π interactions. This aggregation control strengthens the triplet-state population, delivering parallel gains in luminescence and photosensitization without modifying the core chromophore. Emission quantum yields rise from dilute-solution values to 25% in aggregated states and 0.25% in polymethyl methacrylate (PMMA) films, while 1O2 quantum yields reach ∼60% in aggregates and 49% in polystyrene (PS) films. This simple, modular approach couples emission enhancement with photoreactive oxygen production, offering a powerful design platform for multifunctional materials in photodynamic therapy, photocatalysis, and optical sensing
Peptide-based approaches for the race against resistant bacteria
No full text[eng] Antimicrobial resistance to almost all available antibiotics is on the top ten list of global public health challenges of the World Health Organization. Each year, the deaths due to
AMR infections achieve the alarming numbers of 35000 in the European Economic Area
(EEA) and 700000 worldwide. This problem is due to the high capacity of bacteria to
multiply and mutate quickly, caused mainly by the indiscriminate use of broad-spectrum
antibiotics or the excessive use of antibiotics in the veterinary and food industries. The
development of new antibiotics with novel mechanisms of action faces significant challenges,
both scientifically and economically. As a result, the number of antibiotics approved by the
Food and Drug Administration or the European Medicines Agency has drastically decreased
in recent years.
This thesis presents the design, synthesis, characterization and evaluation of the in vitro
activity of 18 analogues of polymyxin B and 9 analogues of murepavadin, two cyclic
antimicrobial peptides. The analogues incorporate a disulfide bond in the macrocycle, aimed
at maintaining the in vitro activity against bacteria, while facilitating peptide proteolysis
compared to an amide bond, potentially reducing renal toxicity. The analogues have been
synthesized by solid-phase peptide synthesis (SPPS) following an Fmoc/tBu protection
scheme. In addition, the mode of action of two polymyxin analogues has been studied using
model membranes and biophysical techniques. Finally, polymyxin B and murepavadin have
also been combined with cyclodextrins, and the formation of inclusion complexes has been
studied by ITC, DSC, TGA, MS, UV-Vis and NMR techniques.[cat] La resistència bacteriana a gairebé tots els antibiòtics disponibles es troba a la llista de
prioritats mundials de salut pública de l’Organització Mundial de la Salut. Cada any, les morts
associades a la resistència antimicrobiana assoleixen l’alarmant nombre de 35.000 a l’Espai
Econòmic Europeu i 700.000 en tot el món. Aquest problema és degut a l’alta capacitat dels
bacteris per multiplicar-se i mutar ràpidament, causada principalment per l’ús indiscriminat
d’antibiòtics d’ampli espectre o l’ús excessiu d’antibiòtics en la indústria veterinària i
alimentària. El desenvolupament de nous antibiòtics amb nous mecanismes d'acció
s'enfronta a importants reptes, tant científics com econòmics. Com a resultat, el nombre
d'antibiòtics aprovats per la Food and Drug Administration o la European Medicines Agency
ha disminuït dràsticament en els últims anys.
Aquesta tesi presenta el disseny, síntesi, caracterització i avaluació de l’activitat in vitro de 18
anàlegs de polimixina B i 9 anàlegs de murepavadina, dos pèptids cíclics antimicrobians. Els
anàlegs incorporen un pont disulfur en el macrocicle, modificació que permetria mantenir
l’activitat in vitro contra els bacteris, i alhora facilitaria la proteòlisi del pèptid en comparació
a un enllaç amida, aconseguint una potencial disminució de la toxicitat renal. Els anàlegs
s’han sintetitzat per síntesi en fase sòlida de pèptids (SPPS) seguint una estratègia de
protecció Fmoc/tBu. A més, s’ha estudiat el mode d’acció de dos dels anàlegs de polimixina
utilitzant models de membrana i tècniques biofísiques. Per últim, també s’ha combinat la
polimixina B i la murepavadina amb ciclodextrines, i s’ha estudiat la formació de complexos
d’inclusió per ITC, DSC, TGA, MS, UV-Vis i tècniques de RMN
Comparative AI Regulation and Digital Sovereignty: EU, USA, China and India. An LIS Perspective
No full textUniversitat de Barcelona. Facultat dInformació i Mitjans Audiovisuals . Presentació de l’alumnat de GIDD i INFOCOM al Congrés BOBCATSSS 2026, el congrés internacional adreçat a alumnat i professorat de Gestió d'Informació i Documentació Digital d'arreu, celebrat a Sibiu (Romania), del 20 al 22 de gener del 2026., Curs: 2025-2026, Director: Boté-Vericad, Juan-JoséThis study compares AI regulation and digital sovereignty approaches in four geopolitical contexts, the European Union, the United States, China, and India, through the lens of Library and Information Science (LIS).
Presentació de l’alumnat de GIDD i INFOCOM al Congrés BOBCATSSS 2026, el congrés internacional adreçat a alumnat i professorat de Gestió d'Informació i Documentació Digital d'arreu, celebrat a Sibiu (Romania), del 20 al 22 de gener del 2026
Bones pràctiques per a l’ús de la intel·ligència artificial generativa a la Universitat de Barcelona
No full textLa intel·ligència artificial generativa (IAG) està impactant en l’aprenentatge, la recerca i la gestió universitària. Fer-ne ús requereix responsabilitat, criteri i seguretat per part de tota la comunitat universitària —estudiantat, professorat i personal tècnic, de gestió i d’administració i serveis—, i ha de contribuir a reduir les bretxes digitals, lingüístiques i d’accessibilitat, de manera que es garanteixin els drets fonamentals i el bon funcionament de la universitat pública