ChatGPT in the Classroom: Boon or Bane for Physics Students' Academic Performance?

This study investigates the influence of ChatGPT, an AI-based language model, on student performance in a physics course. We conducted an experimental analysis with two cohorts of students in a second-semester engineering physics course. The control group (Physics 2 2022B) used traditional teaching methods, while the experimental group (Physics 2 2023A) integrated ChatGPT as a learning tool. Our results indicate that the use of ChatGPT led to a significant decrease in student performance, as evidenced by lower grades and negative Hake factors compared to the control group. In addition, a survey of students revealed conflicting perceptions of the usefulness of ChatGPT in teaching physics. While most recognized its usefulness in understanding concepts and providing information, concerns were raised about its potential to reduce critical thinking and independent learning. These findings suggest that while ChatGPT can be a useful tool, it should be used with caution and as a supplement to traditional teaching methods, rather than as a stand-alone solution. The study underlines the importance of critical and reflective use of AI tools in educational settings and highlights the irreplaceable role of teachers in providing comprehensive educational support.Comment: 9 pages and 13 figure

Lambda^0 polarization as a probe for production of deconfined matter in ultra-relativistic heavy-ion collisions

We study the polarization change of Lambda^0's produced in ultra-relativistic heavy-ion collisions with respect to the polarization observed in proton-proton collisions as a signal for the formation of a Quark-Gluon Plasma (QGP). Assuming that, when the density of participants in the collision is larger than the critical density for QGP formation, the Lambda^0 production mechanism changes from recombination type processes to the coalescence of free valence quarks, we find that the Lambda^0 polarization depends on the relative contribution of each process to the total number of Lambda^0's produced in the collision. To describe the polarization of Lambda^0's in nuclear collisions for densities below the critical density for the QGP formation, we use the DeGrand-Miettinen model corrected for the effects introduced by multiple scattering of the produced Lambda^0 within the nuclear environment.Comment: 9 pages, 6 figures, uses ReVTeX and epsfig.st

Municipal water demand forecasting: Tools for intervention time series

This article introduces some approaches to common issues arising in real cases of water demand prediction. Occurrences of negative data gathered by the network metering system and demand changes due to closure of valves or changes in consumer behavior are considered. Artificial neural networks (ANNs) have a principal role modeling both circumstances. First, we propose the use of ANNs as a tool to reconstruct any anomalous time series information. Next, we use what we call interrupted neural networks (I-NN) as an alternative to more classical intervention ARIMA models. Besides, the use of hybrid models that combine not only the modeling ability of ARIMA to cope with the time series linear part, but also to explain nonlinearities found in their residuals, is proposed. These models have shown promising results when tested on a real database and represent a boost to the use and the applicability of ANNs.This work has been supported by project IDAWAS, DPI2009-11591, of the Direccion General de Investigacion of the Ministerio de Ciencia e Innovacion of Spain, and ACOMP/2010/146 of the Conselleria de Educacion of the Generalitat Valenciana. As well, the authors are grateful to "Aguas de Murcia" for the collaboration in this work and for the availability of the data.This work has been supported by project IDAWAS, DPI2009-11591, of the Direccion General de Investigacion of the Ministerio de Ciencia e Innovacion of Spain, and ACOMP/2010/146 of the Conseller a de Educacion of the Generalitat Valenciana. As well, the authors are grateful to "Aguas de Murcia" for the collaboration in this work and for the availability of the data.Herrera Fernández, AM.; García-Díaz, JC.; Izquierdo Sebastián, J.; Pérez García, R. (2011). Municipal water demand forecasting: Tools for intervention time series. Stochastic Analysis and Applications. 29(6):998-1007. https://doi.org/10.1080/07362994.2011.610161S9981007296Zhou, S. ., McMahon, T. ., Walton, A., & Lewis, J. (2002). Forecasting operational demand for an urban water supply zone. Journal of Hydrology, 259(1-4), 189-202. doi:10.1016/s0022-1694(01)00582-0Bougadis, J., Adamowski, K., & Diduch, R. (2005). Short-term municipal water demand forecasting. Hydrological Processes, 19(1), 137-148. doi:10.1002/hyp.5763Jain, A., & Ormsbee, L. E. (2002). Short-term water demand forecast modeling techniques-CONVENTIONAL METHODS VERSUS AI. Journal - American Water Works Association, 94(7), 64-72. doi:10.1002/j.1551-8833.2002.tb09507.xPeña, D., Tiao, G. C., & Tsay, R. S. (Eds.). (2000). A Course in Time Series Analysis. Wiley Series in Probability and Statistics. doi:10.1002/9781118032978et al. 2000 . Mining Time Series of Meteorological Variables Using Rough Sets—A Case Study, Binding Environmental Sciences and Artificial Intelligent. BESAI 2000, Germany, 7:1–8.Herrera, M., Torgo, L., Izquierdo, J., & Pérez-García, R. (2010). Predictive models for forecasting hourly urban water demand. Journal of Hydrology, 387(1-2), 141-150. doi:10.1016/j.jhydrol.2010.04.005McLeod, A. I., & Vingilis, E. R. (2005). Power Computations for Intervention Analysis. Technometrics, 47(2), 174-181. doi:10.1198/004017005000000094Box, G. E. P., & Tiao, G. C. (1975). Intervention Analysis with Applications to Economic and Environmental Problems. Journal of the American Statistical Association, 70(349), 70-79. doi:10.1080/01621459.1975.10480264Zhang, G. P., & Qi, M. (2005). Neural network forecasting for seasonal and trend time series. European Journal of Operational Research, 160(2), 501-514. doi:10.1016/j.ejor.2003.08.037Zealand, C. M., Burn, D. H., & Simonovic, S. P. (1999). Short term streamflow forecasting using artificial neural networks. Journal of Hydrology, 214(1-4), 32-48. doi:10.1016/s0022-1694(98)00242-xWang, W., Gelder, P. H. A. J. M. V., Vrijling, J. K., & Ma, J. (2006). Forecasting daily streamflow using hybrid ANN models. Journal of Hydrology, 324(1-4), 383-399. doi:10.1016/j.jhydrol.2005.09.032Kneale , P. , See , L. , and Smith , A. 2001 .Towards Defining Evaluation Measures for Neural Network Forecasting Models; Proceedings of the Sixth International Conference on GeoComputation, University of Queensland, Australia.Peña, D., & Rodríguez, J. (2002). A Powerful Portmanteau Test of Lack of Fit for Time Series. Journal of the American Statistical Association, 97(458), 601-610. doi:10.1198/016214502760047122Peña, D., & Rodríguez, J. (2006). The log of the determinant of the autocorrelation matrix for testing goodness of fit in time series. Journal of Statistical Planning and Inference, 136(8), 2706-2718. doi:10.1016/j.jspi.2004.10.026LJUNG, G. M., & BOX, G. E. P. (1978). On a measure of lack of fit in time series models. Biometrika, 65(2), 297-303. doi:10.1093/biomet/65.2.297MONTI, A. C. (1994). A proposal for a residual autocorrelation test in linear models. Biometrika, 81(4), 776-780. doi:10.1093/biomet/81.4.77

D-Fussion: a semantic selective disssemination of information service for the research community in digital libraries

Introduction. In this paper we propose a multi-agent Selective Dissemination of Information service to improve the research community's access to digital library resources. The service also provides a new recommendation approach to satisfy researchers' specific information requirements. Method. The service model is developed by jointly applying Semantic Web technologies (used to define rich descriptions of resources and a concept scheme that helps in indexing and retrieving tasks), fuzzy linguistic modelling techniques (both ordinal and 2-tuple-based approaches, that allow us to flexibly represent and handle information that is subject to a certain degree of uncertainty), as well as content-based and collaborative filtering techniques. Analysis. An experiment has been carried out to test the performance of the proposed model using a prototype and several experts have been asked to assess the recommendations provided by the system. Results. The outcomes of the experiment reveal that the proposed model is feasible and efficient in terms of precision and recall. Conclusions. Semantic Web technologies and fuzzy linguistic modelling provide the means to develop value-added services for digital libraries, which improve users' access to resources of interest to them. Furthermore, the recommendation approach here proposed allows researchers to satisfy specific information needs not covered by traditional recommender systems.Introducción. En este artículo proponemos de un servicio de Diseminación Selectiva de Información multi-agente para mejorar el acceso de la comunidad investigadora a los recursos de bibliotecas digitales. El servicio también proporciona una nueva aproximación a la recomendación para satisfacer los requerimientos de información específicos de los investigadores. Método. El modelo del servicio se desarrolla aplicando conjuntamente las tecnologías de la Web Semántica (usadas para definir descripciones ricas de recursos y un esquema de concepto que ayuden en las tareas de indización y recuperación), las técnicas de modelado lingüístico difuso (tanto la aproximación ordinal y como la basada en 2-tuplas que nos permiten representar y manejar flexiblemente información sujeta a un cierto grado de incertidumbre), así como las técnicas de filtrado basadas en contenido y colaborativas. Análisis. Se realizó un experimento para probar el rendimiento del modelo propuesto usando un prototipo y se han pedido a varios expertos que valoren las recomendaciones proporcionadas por el sistema. Resultados. Los resultados del experimento revelan que el modelo propuesto es factible y eficaz en términos de precisión y relevancia. Conclusiones. Las tecnologías de Web semántica y el modelado lingüístico difuso proporcionan los medios para desarrollar servicios de valor agregado para bibliotecas digitales que mejoran el acceso de los usuarios a los recursos de interés. Además, la aproximación de la recomendación aquí propuesta permite a los investigadores satisfacer necesidades de información específicas no cubiertas por los sistemas de recomendación tradicionales.The research reported here was supported by the Consejería de Innovación, Ciencia y Empresa. Junta de Andalucía, Spain (project SAINFOWEB - 00602) and the Ministerio de Educación y Ciencia, Spain (project FUZZYLING - TIN2007-61079)

Rotura bilateral y simultánea del tendón de Aquiles

La rotura bilateral y simultánea del tendón de Aquiles es un hecho excepcional. La producción de esta lesión en una persona joven, sin antecedentes patológicos ni de administración de ciertos medicamentos es aún más excepcional. El tratamiento quirúrgico y un adecuado proceso de seguimiento y rehabilitación contribuyen a una buena recuperación y pronóstico en los individuos jóvenes y activos con roturas del tendón de Aquiles. Se presenta un caso clínico de una mujer de 21 años tratada quirúrgicamente con buen resultado.The bilateral and simultaneous rupture of Achilles tendon is an excepcional situation. The production of this injury in a young person, without history pathological or administration of certain drugs is even more exceptional. The surgical treatment and a proper process of following-up and rehabilitation help to a good recovery and prognosis in young and active people with Achilles tendon ruptures

Synthetic ability of dinuclear mesocates containing 1,3-bis(diazinecarboxamide)benzene bridging ligands to form complexes of increased nuclearity. Crystal structures, magnetic properties and theoretical studies

International audienceTriple stranded NiII2-metallacyclic complexes Na2.5[Ni2(bpcb)3]·0.5OH·18.5H2O (1) and Na2[Ni2(bpzcb)3]·16H2O (2), and double stranded CuII2-metallacyclic complexes [Cu2(bpcb)2(H2O)2]·8H2O (3) and [Cu2(bpzcb)2(H2O)2]·4H2O (4) have been assembled from the tailored bisbidentate bridging ligands, 1,3-bis(pyrimidine-2-carboxamide)benzene (H2bpcb) and 1,3-bis(pyrazine-2-carboxamide)benzene (H2bpzcb), and the corresponding nitrate salts of the metal ions. Following the “complex as ligand” strategy, 1 can be assembled with either Ni2+, Co2+ ions or the [Mn(acen)Cl] complex to afford unique, neutral, bent trinuclear molecules [MIINiII2(bpcb)3]·xH2O (5 and 6) and the 2D honeycomb-like complex (PPh4){[Ni2(bpcb)3]2[Mn(acen)]3} (7), respectively. In these cases, the Ni2 units are linked to the corresponding metal ions through amidate oxygen atoms and the outward nitrogen atom of one of the pyrimidine rings of the bcpb ligand. The assembly of 2 with Ln3+ ions (Ln3+ = Tb, Gd) leads to one dimensional complexes of formula [{[Ni2(bpzcb)3]Tb(H2O)5}(CF3SO3)·THF·5H2O]n (8) and [{[Ni2(bpzcb)3]Ln(H2O)4(NO3)}·2THF·nH2O]n (9 and 10) (Ln3+ = Gd and Tb), where the dinuclear Ni2 units are joined to two Ln3+ ions exclusively through amidate oxygen atoms of two different ligands. The analyses of the magnetic data indicate that 1–4 exhibit intradinuclear ferromagnetic interactions between the metal ions through a spin polarisation mechanism, as supported by DFT calculations. Trinuclear complexes 5 and 6 show predominant antiferromagnetic coupling, which is a result of an antiferromagnetic interaction between one of the Ni2+ ions of the Ni2 unit and the M2+ ion through the pyrimidine bridging fragment that is stronger than the polarised ferromagnetic interaction between the Ni2+ ions through the bpcb ligand in the dinuclear [Ni2(bpcb)3]2− moiety. Complex 7 shows a dominant antiferromagnetic interaction between the Ni2+ and Mn2+, whereas the Ni2Ln (Ln3+ = Gd, Tb) chain complexes present ferromagnetic interactions inside the Ni2 mesocate unit as well as between the Ni2+ ions of the Ni2 unit and the Ln3+ ions. The magnetic exchange interactions in these new materials have been experimentally analysed and supported by theoretical DFT studies

Composición y estructura de la ictiofauna del río Hondo, México-Belice, con base en el uso del arpón

ResumenSe determinó la composición y estructura de la ictiofauna del río Hondo y la variación espacial de éstas en función de los parámetros ambientales. Se realizaron 3 muestreos durante marzo, abril y mayo de 2012, en 6 sitios a lo largo del río. Los datos usados para determinar la estructura se obtuvieron con ayuda de un arpón de 58.5cm, utilizado durante 2h de buceo libre en cada punto de muestreo. Para complementar la lista de especies se utilizaron redes agalleras, palangres, nasas y anzuelos. Además, se realizó una revisión bibliográfica y se consultó material de la colección de peces de ECOSUR en Chetumal. La lista sistemática se conformó por 40 especies en 33 géneros, 18 familias y 11 órdenes. La familia mejor representada fue Cichlidae, incluida la especie exótica Oreochromis niloticus. Los parámetros ambientales que mejor describieron la variación de la distribución y abundancia en los peces en el río Hondo fueron: la anchura del río, distancia a la boca, transparencia, profundidad, concentración de oxígeno disuelto y conductividad. La relación entre las especies y las variables ambientales fue alta en ambos ejes (0.89 y 0.79). Ambientalmente, el río se puede zonificar en 3 partes, aunque su ictiofauna puede dividirse en 2 conjuntos principales.AbstractComposition and structure of the Hondo River ichthyofauna and its spatial variation were determined as a function of environmental parameters. Six sites along the river were sampled in March, April and May 2012. Data for estimating structure of fish assemblages was obtained by means of a 58.5cm harpoon during 2 hours of free diving at each sampling site. The species list for the study area was completed with the aid of gillnets, longlines, double-cone traps, and hook-and-line. In addition, a bibliographical research performed as well as the ichthyological collection of ECOSUR at Chetumal was checked. The systematic list includes 40 species in 33 genera, 18 families and 11 orders. The richest family was Cichlidae, including the exotic Oreochromis niloticus. The environmental parameters that best described distribution and abundance of fish in the Hondo River were river width, distance to mouth, transparency, depth, dissolved oxygen concentration, and conductivity. Correlation between species and environmental parameters was high in both axis (0.89 and 0.79). The river was classified into 3 environmental zones, although its fish fauna could be divided in 2 main assemblages

Frontispiece: Lanthanide tetrazolate complexes combining single-molecule magnet and luminescence properties: The effect of the replacement of tetrazolate N3 by β-Diketonate Ligands on the anisotropy energy barrier

Three new sets of mononuclear LnIII complexes of general formulas [LnL3]·CH3OH (LnIII = Yb (1), Er (2), Dy (3), Gd (4) and Eu (5)), [LnL2(tmh)(CH3OH)]·n H2O·m CH3OH (LnIII = Yb (1b), Er (2b), Dy (3b), Gd (4b)) and [LnL2(tta)(CH3OH)]·CH3OH (LnIII = Yb (1c), Er (2c), Dy (3c), Gd (4c) have been prepared from the reaction of Ln(CF3SO3)·nH2O salts with the tridentate ligand 2-(tetrazolate-5-yl)-1,10- phenanthroline (HL). For the two latter sets, additionally with the respective β- diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) or 2-thenoyltrifluoroacetonate (tta). In the [LnL3]·CH3OH complexes the LnIII ions are coordinated to three phenanthroline-tetrazolate ligands showing a LnN9 coordination sphere. Dynamic ac magnetic measurements for 1 – 3 reveal that these complexes only exhibit single molecule magnet (SMM) behaviour when an external dc magnetic field is applied, with Ueff values of 11.7 K (1), 16.0 K (2) and 20.2 K (3). When the tridentate phenanthrolinetetrazolate ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1b – 3b) or tta (1c – 3c), a significant increase in Ueff occurs and, in the case of the DyIII derivates 3b and 3c, out-of-phase χ’’ signals below 15 K and 10 K, respectively, are observed under zero-dc magnetic field. CASSCF+RASSI ab initio calculations performed on the DyIII derivates support the experimental results. Thus, for 3 the ground Kramers’ doublet is far from being axial and the first excited state is found to be very close in energy to the ground state so the relaxation barrier in this case is almost negligible. Conversely, for 3b and 3c, the ground Kramers’ doublet is axial with a small quantum tunneling of the magnetization (QTM) and the energy difference between the ground and first Kramers’ doublets is much higher, which allows these compounds to behave as SMMs at zero-field. Moreover, these calculations support the larger Ueff observed for 3b compared to 3c. Additionally, the solid-state photophysical properties of 1, 2, 4 and 5 show that the phenanthroline tetrazolate ligand can act as an effective antenna to sensitize the characteristic YbIII, ErIII and EuIII emissions through an energy transfer process

Lanthanide tetrazolate complexes combining single-molecule magnet and luminescence properties: the effect of the replacement of tetrazolate n3 by β-diketonate ligands on the anisotropy energy barrier

Three new sets of mononuclear LnIII complexes of general formulas [LnL3]⋅CH3OH [LnIII=Yb (1), Er (2), Dy (3), Gd (4), and Eu (5)], [LnL2(tmh)(CH3OH)]⋅n H2O⋅m CH3OH [LnIII=Yb (1 b), Er (2 b), Dy (3 b), Gd (4 b)], and [LnL2(tta)(CH3OH)]⋅CH3OH [LnIII=Yb (1 c), Er (2 c), Dy (3 c), Gd (4 c)] were prepared by the reaction of Ln(CF3SO3)⋅n H2O salts with the tridentate ligand 2-(tetrazol-5-yl)-1,10-phenanthroline (HL) and, for the last two sets, additionally with the β-diketonate ligands 2,2,6,6-tetramethylheptanoate (tmh) and 2-thenoyltrifluoroacetonate (tta), respectively. In the [LnL3]⋅CH3OH complexes the LnIII ions are coordinated to three phenanthroline tetrazolate ligands with an LnN9 coordination sphere. Dynamic ac magnetic measurements on 1–3 reveal that these complexes only exhibit single-molecule magnet (SMM) behavior when an external dc magnetic field is applied, with Ueff values of 11.7 K (1), 16.0 K (2), and 20.2 K (3). When the tridentate phenanthroline tetrazolate ligand is replaced by one molecule of methanol and the β-diketonate ligand tmh (1 b–3 b) or tta (1 c–3 c), a significant increase in Ueff occurs and, in the case of the DyIII complexes 3 b and 3 c, out-of-phase χ′′ signals below 15 and 10 K, respectively, are observed in zero dc magnetic field. CASSCF+RASSI ab initio calculations performed on the DyIII complexes support the experimental results. Thus, for 3 the ground Kramers’ doublet is far from being axial and the first excited state is found to be very close in energy to the ground state, so the relaxation barrier in this case is almost negligible. Conversely, for 3 b and 3 c, the ground Kramers’ doublet is axial with a small quantum tunneling of the magnetization, and the energy difference between the ground and first Kramers’ doublets is much higher, which allows these compounds to behave as SMMs at zero field. Moreover, these calculations support the larger Ueff observed for 3 b compared to 3 c. Additionally, the solid-state photophysical properties of 1, 2, 4, and 5 show that the phenanthroline tetrazolate ligand can act as an effective antenna to sensitize the characteristic YbIII, ErIII, and EuIII emissions through an energy-transfer process

Stability of Switched Linear Discrete-Time Descriptor Systems with Explicit Calculation of a Common Quadratic Lyapunov Sequence

Abstract-In this paper, the stability of a switched linear regular descriptor system is considered. It will be shown that if a certain simultaneous triangularization condition on the subsystems is fulfilled and all the subsystems are stable then the switched system is stable under arbitrary switching. The result involves different descriptor matrices and extends to the singular case well-known results from the standard one. Furthermore, an explicit construction of a common Lyapunov sequence for a set of discrete-time regular linear descriptor subsystems is performed. The main novelty of the proposed approach is that the common Lyapunov sequence can be easily computed in comparison with previous works which either presented computationally-demanding methods or did not construct the common Lyapunov sequence explicitly