Publications

Abstract Teacher training for the use of technological resources has been widely researched in educational studies. Situated in the context of such investigations, research on digital competences in education has also gained prominence in the last decade. Considering the breadth of work conducted in these areas and the need for integration between the different theoretical-practical domains that permeate this field of study, the main objective of this research is to develop a theoretical framework to bridge the references of teaching and digital competency within Teaching Professional Knowledge. Methodologically, a systematic literature analysis was conducted, beginning with an initial bibliometric analysis using VOSviewer software tool, followed by the categorization of a selected corpus of works. Subsequently, an analysis of the relationships between the teaching of digital competences and the knowledge domains related to the references of Pedagogical Content Knowledge and Pedagogical and Technological Content Knowledge was carried out. The systematic review allowed us to infer that prevailing trends in research on the teaching of digital competency are related to the assessment of competences in different groups of teachers, to the proposal of training actions, and to theoretical studies. It was evident that the theoretical framework known as DigCompEdu serves as a foundation for various research endeavors. Relations between the domains of teaching professional knowledge and digital competences were identified, and based on this identification, a theoretical framework is discussed and proposed to consider the possibility of articulating actions for the development of teaching digital competences in the context of teacher training oriented towards Pedagogical and Technological Content Knowledge.

Abstract Empowering students with a robust Science, Technology, Engineering, and Mathematics (STEM) education, while equipping their teachers with comprehensive training, fosters critical thinking and problem-solving skills, which are important aspects of innovation, social progress, and advancement. The main objective of this study is to investigate how a STEM-lab activity - an experimental chemistry laboratory activity integrated with Arduino prototyping - implemented within a teacher education program can promote the development of professional knowledge that enables the development of activities aligned with the STEM approach among pre-service teachers. Twenty Portuguese pre-service physics and chemistry teachers participated in the study. Pre- and post-activity tests, incorporating closed and open-ended questions, were used to assess participants’ perceptions. Data analysis included quantitative assessment of conceptual gains and qualitative content analysis of reflective responses. The results suggest that the activity fosters a reflective process among pre-service chemistry teachers, enabling them to integrate STEM components with a socio-scientific contextual approach and encouraging critical consideration of adapting STEM activities for greater applicability and effectiveness in secondary education. While this approach significantly enhances pedagogical effectiveness, challenges persist in identifying aspects related to engineering and using Arduino prototyping. © 2025 by Author/s

Abstract The quality of initial and continuous training for primary-school teachers is essential to fostering science education and building strong scientific foundations. This qualitative case study, conducted over two consecutive school years in Portugal, examines the impact of a continuous professional development program aimed at addressing gaps in primary teachers' experimental science teaching. The program took place in the municipality of Penafiel and was organized by a university research team in collaboration with local schools. The program combined face-to-face sessions, in-school support from expert monitors, and the provision of teaching resources. Data were drawn from Individual Final Reflective Reports written by 108 teachers, all of whom participated through mandatory enrollment in the local training initiative. The sample was therefore exhaustive, covering the entire population targeted by the municipality. The reports were analyzed using qualitative content analysis, following an inductive coding process supported by peer validation. NVivo (version 14) software was used to assist in the categorization and management of textual data. The analysis revealed that teachers highly valued the training, particularly highlighting the relevance of the content, the effectiveness of the methodologies, and the training's practical utility in overcoming classroom challenges. The program enhanced teachers' confidence in implementing experimental activities and improved their teaching practices. The study underscores the importance of continuous professional development in strengthening teacher qualifications and science education. Limitations include reliance on self-reported reflections, the focus on a single municipality, and the absence of triangulation with classroom observations. Nevertheless, the program demonstrates that combining active methodologies, contextualized classroom support, and resource provision is a promising model for teacher professional development. The implications are relevant for policymakers, training centers, and teacher educators designing continuous professional development initiatives. Future research should explore scalability, longitudinal effects, and the comparative effectiveness of different continuous professional development mode.

Abstract In 2016, the Planet & aacute;rio do Porto - Ci & ecirc;ncia Viva Center (PP-CCV) launched a new approach to its in-service teacher training plan (TTP). This plan was structured around five key elements: (i) its relevance for teacher career progression, being free of charge and open to educators of all school subjects; (ii) an inquiry-based learning design, grounded in the most updated scientific knowledge and methods; (iii) a direct alignment with the school curriculum; (iv) the use Astronomy as a vehicle for interdisciplinary learning across several school subjects; and (v) a commitment to democratizing science leveraging the school system's multiplier effect. In this article, we present the different stages in the development of the TTP, which include institutional partnership with NASE (Network for Astronomy School Education) and EAAE (European Association for Astronomy Education). The program enrolled 3,208 teachers from all the Portuguese districts as well as from the Community of Portuguese Speaking Countries (CPLP). The PP-CCV's TTP, practical and replicable, proved to be an effective channel for bringing cutting-edge scientific knowledge and practices to educational contexts - especially in communities with historically low engagement with science, not by choice, but due to systemic barriers in access to scientific education.

Abstract Optical fibers have been extensively applied in optical sensing platforms for their large bandwidth, stability, light weight and accessibility. This work presents a theoretical analysis of an optical fiber surface plasmon resonance system for refractometric sensing applications. The device consists of a multilayer hyperbolic metamaterial (HMM) composed of concentric Au/TiO2 alternate layers in optical fiber matrix. HMMs exhibit hyperbolic dispersion (HD) and the interaction of different plasmonic modes at each interface of the HMM is reported to enhance light-matter coupling, leading to an increased refractometric sensitivity. The HD and its effects on sensor performance are numerically investigated by effective medium theory (EMT) and backed by the exact transfer matrix method (TMM). The maximum sensor performance was attained for a configuration with 2 bilayers with 30 nm thickness for a metal fill fraction (rho) of 0.7, achieving a figure of merit (FOM) of 18.45. A direct comparison with a plasmonic Au optical fiber sensor returned an optimized FOM of 5.74, therefore achieving over a three-fold increase in sensor performance, assessing the potential of HMM as highly refractometric sensitive platforms.

Abstract Hydrogen (H-2) infrastructure is the focus of many initiatives for the planned energetic transition, but its volatility and flammability require extensive safety measures to prevent leakages and explosions. Magnesium thin films have been investigated not only for H-2 storage but also as switchable mirrors, which drastically change their optical properties when hydrogenated. Due to their lower cost compared to other hydride-forming or plasmonic metals commonly used in optical sensing, Mg-based H-2 fiber sensors have the potential to be both affordable and effective for scalable deployment in industrial settings. To this end, multilayer thin-film structures with Mg and palladium as adsorption catalyst were deposited on single-mode fiber tips, and H-2 loading/unloading processes were tested in a controlled flow gas setup. In parallel, an optical interrogation system prototype was developed, enabling fast data acquisition of fiber-tip reflectivity across multiple sensing probes at a wavelength of 1550 nm. Preliminary testing suggests fast response times of a few seconds for significant drops in reflectivity, facilitating straightforward detection of H-2 leaks using thresholding methods. Planned future work includes performance comparison with simpler sensing structures, durability and contaminant testing, and response time optimization.

Abstract Hyperbolic Metamaterials (HMM) are a class of photonic metamaterials exhibiting hyperbolic dispersion due to strong anisotropy. This work presents a numerical analysis and experimental characterization of a hyperbolic multilayer structure supporting surface plasmon polaritons for refractometric sensing applications. The device consists of a multilayer HMM composed of alternate Au and TiO2 layers, and the interaction of different plasmonic modes at each interface of the HMM is reported to enhance light- matter coupling, leading to an increased refractometric sensitivity. The hyperbolic dispersion and its effects on sensor performance are numerically investigated using the Effective Medium Theory (EMT) and validated through the Transfer Matrix Method (TMM). A fair match was obtained between EMT and TMM simulated spectra, validating the EMT approach for simulation of the optical properties of multilayer HMMs. Despite not predicting figures of merit (FOM) accurately, both the TMM and EMT approaches closely replicated the obtained experimental refractometric sensitivity.

Abstract Concrete structures require precise temperature and humidity monitoring during curing to ensure optimal strength and prevent defects like cracking. A compact optical sensing system was developed using a single fiber that can be embedded directly within the concrete. The system functions as both a temperature and humidity sensor when paired with a spectral interrogation unit operating in the 1500-1600 nm range. Temperature monitoring is achieved through a Fiber Bragg Grating, while humidity sensing is facilitated by a Fabry-Perot interferometer at the fiber tip. The interferometer cavity is formed with a layer of polyvinylpyrrolidone (PVP). Initial air humidity sensor tests showed a significant change in the interference period with RH, demonstrating low hysteresis and high reproducibility. Calibration of one sensor revealed an approximately 3 nm period decrease when RH increased from 55% to 95%, with results suggesting a quadratic relationship between the interference period and RH values.

Abstract This study investigates the fabrication of plasmonic optical fiber sensors for glyphosate detection, employing silver thin film coatings deposited via the Tollens' reaction and further enhanced with protective gold plating. Silver films were produced through electroless deposition, forming rough plasmonic surfaces with localized hotspots that amplify the electromagnetic field. Surface roughness effects on the creation of hotspots were first evaluated numerically using the finite element method (FEM) and later experimentally assessed the impact on optical response. Furthermore, to address the inherent susceptibility of silver to oxidation and corrosion, a gold plating was applied using the Kirkendall effect, selectively replacing surface silver atoms with gold. This approach significantly improved the chemical stability of the sensors while preserving their plasmonic properties. This configuration was applied in developing a biosensor, using aptamers, for detecting glyphosate in concentrations ranging from 10(-1) to 10(4) mu g/L. The results demonstrated a sensitivity of 25.08 +/- 0.22 nm/(mu g/L) and a limit of detection (LOD) of 0.04 mu g/L, nearly ten times lower than the European Union's safety limit for glyphosate. Experimental results highlight the potential of this fabrication approach for developing sensitive, stable, and scalable plasmonic sensors tailored for environmental and agricultural monitoring applications.