King Juan Carlos University
Archivo Abierto Institucional de la Universidad Rey Juan CarlosNot a member yet
28087 research outputs found
Sort by
Revisión crítica de la aplicación de la doctrina Saquetti mediante el recurso de casación
No full textEn la actualidad, el Tribunal Supremo se encuentra ante un reto importante, al que ha llegado en su bienintencionado deseo de implementar la doctrina de la Sentencia Saquetti y velar así por los derechos de los recurrentes frente a la imposición de sanciones administrativas consideradas de naturaleza penal. Después de más de 4 años del pronunciamiento del TEDH se han admitido ya decenas de Autos con contenidos y estructuras heterogéneas con el objetivo de hacer efectivo el derecho de reexamen. Y se siguen admitiendo. Asimismo, ya se han dictado diversas sentencias que merecen un análisis detenido. A la vista de todo ello, veremos si la andadura recorrida por el TS ha permitido abrir una auténtica vía para la defensa de los recurrentes o se está mostrando ineficaz y el único resultado es llevarlos a una suerte de agotamiento procesal. Y es que, como veremos, en algunos casos, la estimación del recurso de casación solo lleva al recurrente al punto de partida no constituyendo, en puridad, una doble instancia procesal. Por todo ello, quizás sea oportuno nuevamente realizar una relectura de la precitada sentencia Saquetti y recordar, asimismo, lo que en 2021
ya se advertía en diferentes lugares: que el recurso de casación, tal y como fue concebido en la reforma de 2015, entorno a la preponderancia del interés casacional objetivo, sigue siendo una vía inoperativa, impropia e inadecuada para respetar el derecho al reexamen de las sentencias condenatorias de sanciones administrativas grave
Controlling transient chaos in the Lorenz system with machine learning
No full textThis article presents a novel approach for controlling transient chaos in the Lorenz system using a transformer-based machine learning model. Transient chaos refers to chaotic dynamics that occur temporarily before a system stabilizes into a non-chaotic state. The challenge lies in sustaining this chaotic regime, which is often desirable in applications like energy harvesting or population modeling. Traditional control methods rely on the computation of safety functions to determine minimal control inputs that keep the system within a chaotic regime. However, these methods are computationally intensive and require detailed knowledge of the system’s dynamics.
The proposed method addresses these limitations by leveraging a transformer neural network trained to estimate safety functions directly from noisy trajectory data. This data-driven model eliminates the need for iterative computation and physical system modeling, offering a significant reduction in computational complexity. The study focuses on a reduced one-dimensional map of the Lorenz system, constructed from a Poincaré section, to efficiently apply control and compare results between classical and machine learning approaches.
Performance is evaluated under different noise levels. In both low and high noise scenarios, the machine learning-based safety function successfully confines trajectories within the desired region, maintaining the system in the transient chaotic state. Comparisons show that while the machine learning approach tends to slightly overestimate or underestimate safe regions, it remains effective in practice, requiring only marginally higher control efforts. Visual analysis of safe sets and control trajectories confirms the validity of the method.
The results demonstrate that transformer-based models offer a powerful alternative for chaos control in nonlinear dynamical systems. This technique is particularly useful for systems where traditional modeling is impractical or where rapid, real-time control is necessary. Future improvements could enhance the accuracy of the predicted safe sets, especially in scenarios with complex or highly variable noise. Overall, this work paves the way for scalable, efficient, and generalizable control strategies using modern machine learning tools.
Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature.This paper presents a novel approach to sustain transient chaos in the Lorenz system through the estimation of safety functions using a transformer-based model. Unlike classical methods that rely on iterative computations, the proposed model directly predicts safety functions without requiring finetuning or extensive system knowledge. The results demonstrate that this approach effectively maintains chaotic trajectories within the desired phase space region, even in the presence of noise, making it a viable alternative to traditional methods. A detailed comparison of safety functions, safe sets, and their control performance highlights the strengths and trade-offs of the two approaches
Spanish University Students’ Experiences and Perceptions of the Spectrum of Teaching Styles and Application of the Model Based on the Self-Determination Theory
No full textPurpose: To test the application of the four-group model of teaching styles based on the self-determination theory in a population of Spanish university students and to analyze the Spanish university students’ experiences and perceptions of the teaching styles according to this model. Method: This research followed a descriptive quantitative methodology using a survey. A questionnaire on students’ experiences and perceptions of teaching styles was administered to a total of 667 Spanish university students of physical education (77.8% men and 22.2% women, aged between 18 and 30 years). Results: All the factors presented an acceptable–good reliability index (α ≥ .7), and the multivariate analysis was significant for the variables year and ownership Q3 (p ≤ .05). Conclusion: The four-factor model was applicable to the Spanish university population, and the directive cluster was given higher scores by students in the first year, whereas students in the last year preferred the discovery cluster
Historia de las doctrinas del interés y la usura (Póster)
No full textPóster/esquema gráfico que representa las principales doctrinas sobre la usura y el interés a lo largo de la historia. Desde el rechazo de los filósofos griegos hasta los pensadores más influyentes del siglo XX, pasando por los primeros defensores del interés y la teoría de Böhm-Bawerk. Presentado por primera vez en el XIV Congreso Internacional de la Asociación Española de Historia Económica (AEHE), celebrado en la Universidad de Las Palmas de Gran Canaria del 21 al 24 de enero de 2025. Asimismo, utilizado en las asignaturas de Historia del Pensamiento y de las Instituciones Económicas, así como en Historia Económica y Social en la Universidad Rey Juan Carlos
What Drives Pro-Environmental Behavior? Investigating the Role of Eco-Worry and Eco-Anxiety in Young Adults
No full textClimate change (CC) is one of the most urgent challenges of our time. Research suggests that pro-environmental behaviors (PEB) are essential to address this crisis, encompassing sustainable consumption (e.g., recycling or saving energy) and active participation (e.g., protesting or donating). In this regard, young adults play a significant role as change agents. Considering the previous literature affirming the importance of CC emotions on PEB, this study aims to analyze the mediating role of eco-worry and eco-anxiety in the relationship between two cognitive antecedents (general willingness to behave proenvironmentally and CC agency) and two types of PEB (sustainable consumption and active participation). To do so, we gathered a sample of 308 young adults aged 18 to 30 years. Results show that eco-worry mediates the relationships between both antecedents (willingness and CC agency) with sustainable consumption and active participation. In contrast, eco-anxiety in young adults only mediates the relationship between CC agency and active participation. Our findings suggest that eco-worry plays a crucial role in promoting PEB more broadly, while eco-anxiety appears to be only relevant in influencing active participation. These results contrast with others observed in the adult population, so further studies are needed to confirm these findings
Impact of economic policy uncertainty on the performance of SMEs in a university environment
No full textPurpose – This study aims to analyze how economic policy uncertainty (EPU) influences the economic and financial performance of small and medium-sized enterprises (SMEs) located in a university environment.
Design/methodology/approach – To achieve the proposed objective, a sample of 449 companies located in the university environment of the Rey Juan Carlos University of Madrid (Spain) was taken for the period 2012–2020. Given the temporal and cross-sectional nature of the data, the chosen methodology was panel data analysis.
Findings – The results show how EPU has a negative impact on the performance of these SMEs. However, firm size and age are not influential factors in the relationship between EPU and the performance of SMEs.
Practical implications – This evidence provides more knowledge to SMEs located near a university to make decisions under uncertainty. Fiscal and monetary authorities should be aware of the impact of EPU, not only economic but also social.
Originality/value – This research provides more knowledge on the impact of EPU on firm performance, focusing on a specific segment of SMEs, namely those located in a university environment
Boosting the performance of polymer electrolyte membrane fuel cells with porous flow fields: Pros and cons
No full textThis work was supported by project TED2021-131620B-C21 of the Spanish Research Council .The design of the cathode flow field plays a relevant role in the performance of proton exchange membrane fuel cells (PEMFC). Recently, porous flow fields have emerged as an alternative to conventional rib/channel flow fields (e.g., serpentine flow field) in an attempt to increase PEMFC performance. In this work, we aim to shed light on pros and cons of both bipolar plate types by analyzing transport through porous and rib/channel flow fields using experimental and numerical work. The experimental polarization curves and oxygen transport resistance data of a cathode porous flow field are used to validate the numerical model. Then, a comprehensive parametric study of the model is presented, involving both operating and constructive parameters. The results show that the main advantages of porous flow fields are: () the improvement of oxygen transport, () the decrease of flooding in the cathode MEA, and () the increase of the distribution homogeneity in the in-plane direction of physical parameters (e.g., current density and temperature). In contrast, the main disadvantages are: () the potential effect of electrical contact resistances between porous surfaces, and () the decrease of the water removal drag force in the cathode channel. The above two issues can be mitigated using: () thinly manufactured foams and/or increasing the assembly compression, and () hybrid porous flow fields that incorporate a rib/channel pattern with fine pore-size porous ribs
Futuros[Im]posibles
No full textFuturos [Im]posibles es una propuesta visual y conceptual que especula sobre nuevas formas de habitar en escenarios tecnológicos, interplanetarios y posthumanos. Combinando diseño computacional, modelado paramétrico e inteligencia artificial, la exposición presenta arquitecturas que trascienden la función y la materia, abriendo preguntas sobre el futuro del espacio, el cuerpo y la percepción. Es una invitación a pensar lo arquitectónico como experimento radical en tiempos inciertos.Futuros [Im]posibles es una exposición que explora el potencial especulativo de la arquitectura en un contexto de aceleración tecnológica y colapso de certezas. A través de imágenes generadas mediante modelado tridimensional, renderizado avanzado e inteligencia artificial, se proponen escenarios que trascienden la representación convencional: ciudades flotantes, hábitats interplanetarios, espacios inestables y arquitecturas sintientes. La muestra no ofrece soluciones, sino provocaciones visuales que invitan a imaginar formas alternativas de habitar, más allá de lo funcional y lo predecible. Este trabajo se sitúa en la convergencia entre diseño computacional, pensamiento proyectual radical y experimentación con tecnologías emergentes, ensayando una arquitectura que ya no representa el mundo: lo anticipa, lo cuestiona y lo inventa
Moderating Effect of Family Function Between Dysfunctional Thoughts and Emotional Distress in Dementia Caregivers: Kinship Differences
No full textThe present project was supported by the Ministerio de Ciencia e Innovaciín – Agencia Estatal de Investigaciín (AEI), Spain under Grants PID2019-106714RB-C21 and PID2019-106714RB-C22. Cristina Huertas Domingo was supported by a Pre-Doctoral Grant from the Spanish Ministry of Education and Culture. Lucía Jiménez-Gonzalo and José Fernandes-Pires were supported by predoctoral grants from the URJC.Caring for a family member with dementia impacts caregivers' mental health. Daughters who provide care seem to be particularly affected due to their multiple roles. The study analyzed the role of dysfunctional thoughts and family function for understanding caregivers' depressive and anxiety symptoms, focusing on the potential moderating effect of family function in the relationship between dysfunctional thoughts and distress. In addition, it examined potential differences in the obtained associations considering the kinship relationship. A total of 278 family caregivers of people with dementia were divided into four groups (wives, husbands, daughters, sons). Sociodemographic variables, family obligations, dysfunctional thoughts, frequency and discomfort associated with problematic behaviors, family function, anxious symptomatology, and depressive symptomatology were assessed. Regression analyses revealed that the moderating effect of family function was significant only for daughters. For depressive symptomatology, the model explained 28.6% of the variance for daughters, showing that high levels of dysfunctional thoughts were associated with increased depressive symptoms when family function was low or intermediate (p < 0.001), but not when it was high. Similarly, for anxious symptomatology, the model explained 23.9% of the variance for daughters, with dysfunctional thoughts again associated with higher anxiety symptoms when family function was low or intermediate (p < 0.001), but not significantly when family function was high. These findings suggest that a well-functioning family may buffer the negative impact of rigid caregiving beliefs, particularly for daughters. The results highlight the importance of interventions aimed at improving family dynamics to enhance caregivers' well-being
Production of high value-added phenolic compounds through lignin catalytic pyrolysis over ion-exchanged hierarchical ZSM-5 and Beta zeolites
No full textThe authors gratefully acknowledge the financial support from the Spanish Ministry of Science, Innovation and Universities and the Spanish State Research Agency through projects ADBIOCAP (PID2020-114740RB-C22 MICIU/AEI/10.13039/501100011033) and HYPYCAT (PID2023-147355OB-C22 MICIU/AEI/10.13039/501100011033).Synthesised H-ZSM-5 and H-Beta zeolites with hierarchical porosity (h-H-ZSM-5 and h-H-Beta) have been ion-exchanged with alkali (Na+ and K+) and alkaline-earth (Mg2+) metals and have been evaluated as catalysts to produce high value-added products through catalytic pyrolysis of lignin. In comparison with the thermal test, hierarchical zeolites in acid form are effective catalysts for lignin pyrolysis, favouring the production of valuable light compounds although reducing bio-oil* yield and increasing gas and coke formation. In this way, h-H-ZSM-5 zeolite promotes the formation of oxygenated aromatics, being guaiacols and syringols the major products. Alkali-exchanged variants of this zeolite enhance demethylation reactions improving the selectivity towards 2-methoxy-phenol and syringol, by modifying acid site properties. On the other hand, h-H-Beta zeolite, with larger pore size and stronger acidity, leads to higher concentration of oxygenated aromatics for both parent and ion-exchanged catalysts. Specifically, h-KH-Beta promotes the production of 2-methoxy-phenol and syringol. Besides, h-MgH-Beta stands out for its greater selectivity towards phenol and alkylphenols, such as dimethylphenol. Overall, the combination of accessibility, provided by the hierarchical porosity, with the different nature and strength of the acid sites, induced by the ion-exchange with alkali and alkaline-earth metals, allows tailoring the lignin catalytic pyrolysis process to selectively produce high value-added compounds