BURJC-Digital es el nombre del Repositorio Institucional de la Universidad Rey Juan Carlos. Tiene como objetivo archivar y preservar la producción científica resultante de la actividad académica e investigadora de la comunidad universitaria, con el fin de difundirla en acceso abierto.
Envíos recientes
A critical non-homogeneous heat equation with weighted source
(Cambridge University Press, 2025-03-06) Iagar, Razvan Gabriel; Sánchez, Ariel
Some qualitative properties of radially symmetric solutions to the non-homogeneous heat equation with critical density and weighted source
|x|−2∂tu=Δu+|x|σup,(x,t)∈RN×(0,T),
are obtained, in the range of exponents p>1 , σ≥−2 . More precisely, we establish conditions fulfilled by the initial data in order for the solutions to either blow-up in finite time or decay to zero as t→∞ and, in the latter case, we also deduce decay rates and large time behavior. In the limiting case σ=−2, we prove the existence of non-trivial, non-negative solutions, in stark contrast to the homogeneous case. A transformation to a generalized Fisher–KPP equation is derived and employed in order to deduce these properties.
Phylogenetic study of the Cladonia cervicornis group (Cladoniaceae, Lecanorales) discloses a new species, Cladonia teuvoana
(Cambridge University Press, 2024-12-12) Pino-Bodas, Raquel; Herrero, Alberto; Aptroot, André; Søchting, Ulrik; McMullin, Richard Troy; Burgaz, Ana Rosa
The Cladonia cervicornis group comprises lichen-forming fungi characterized by having scyphi with central proliferations. It includes c. 20 species globally. The taxonomy of this group is poorly resolved, with many species not thoroughly disentangled. The focus of this study is the European species in the C. cervicornis group. In order to estimate the phylogenetic relationships of these species, six loci were used: ITS rDNA, IGS rDNA, RPB1, RPB2, ef1α and cox1. Species delimitation methods (ASAP, PTP and GMYC) were used to infer the species boundaries based on four loci, ITS rDNA, IGS rDNA, cox1 and RPB2. A morphological analysis based on multivariate methods was performed to assess the importance of phenotypic differences among the lineages. The phylogenetic reconstructions placed the species of this group in the subclade Cladonia. Five lineages were recovered, corresponding to C. cervicornis, C. macrophyllodes, C. pulvinata, C. verticillata and a new lineage that we describe here, C. teuvoana. Our analyses revealed that Cladonia cineracea, C. stricta and C. trassii are polyphyletic.
Self-perceptions of Aging and Distress in Middle-aged and Older Adults. The Role of Perceived Control and Pleasant Activities
(Cambridge University Press, 2025-04-08) García-García, Laura; Fernandes-Pires, José Adrián; Márquez-González, María; Pedroso-Chaparro, María del Sequeros; Benito-Rincón, Claudia; Pérez-Cardona, Luis Manuel; Losada-Baltar, Andrés
Previous studies have shown the importance of self-perceptions of aging in predicting psychological distress throughout the life cycle. However, little is known about the processes through which self-perceptions of aging influence distress. The aim of the present study is to analyze the potential indirect effects of perceived control and pleasant activities in the association between self-perceptions of aging and depression and anxiety symptoms in middle-aged and older adults. A total of 315 people over 40 years of age (Mage = 58.8; SD = 10.8; 67.9% women) participated. Two indirect effects analysis models were conducted in serial with the aim of analyzing the role of perceived control and pleasant activities in the relationship between the self-perceptions of aging and depressive (model 1) and anxiety (model 2) symptomatology. A direct effect was observed between self-perceptions of aging and depressive, and anxious symptomatology. In addition, indirect associations through the variables perceived control and pleasant activities were significant. The tested models explained 46.1% of the variance in depressive symptomatology and 34.8% of the variance in anxiety. The results of this study confirm the association between self-perceptions of aging and psychological distress. This association is exerted through lower perception of control and fewer pleasant activities. Interventions aimed at promoting effective coping strategies that favor perceived control, activity and emotional well-being should include a module on identifying and modifying of negative self-perceptions of aging in middle-aged and older adults.
Polynomial Graphical Lasso: Learning Edges From Gaussian Graph-Stationary Signals
(Institute of Electrical and Electronics Engineers, 2025-02-21) Buciulea, Andrei; Ying, Jiaxi; Marques, Antonio G.; Palomar, Daniel P.
This paper introduces Polynomial Graphical Lasso (PGL), a new approach to learning graph structures from nodal signals. Our key contribution lies in modeling the signals as Gaussian and stationary on the graph, enabling the development of a graph learning formulation that combines the strengths of graphical lasso with a more encompassing model. Specifically, we assume that the precision matrix can take any polynomial form of the sought graph, allowing for increased flexibility in modeling nodal relationships. Given the inherent complexity and nonconvexity of the optimization problem, we (i) propose a low-complexity algorithm that alternates between estimating the graph and precision matrices, and (ii) characterize its convergence. We evaluate the performance of PGL through comprehensive numerical simulations using both synthetic and real data, demonstrating its superiority over several alternatives. Overall, this approach presents a significant advancement in graph learning and holds promise for various applications in graph-aware signal analysis and beyond.
Virtual, Augmented, and Extended Reality Applied to Science Communication: A Systematic Literature Review
(Institute of Electrical and Electronics Engineers, 2025-05-12) Romero-Luis, Juan; Rubio-Tamayo, José Luis; Sanchez-Acedo, Alberto; Wuebben, Daniel; Codesido-Linares, Valeri
Extended reality (XR)—which includes virtual reality (VR) and augmented reality (AR)—is becoming increasingly popular for sharing scientific knowledge. This research evaluates the state-of-the-art in XR for scientific communication. Our two-phase methodology began with a Systematic Literature Review, identifying 94 relevant articles and conference papers from the last decade (2013- 2023) sourced from the Web of Science and SCOPUS databases. These publications show scholars and practitioners using XR to convey scientific findings, foster awareness, ignite interest, shape opinions, and enhance understanding. In the second phase, we applied data clustering and analysis. Our findings highlight a significant increase in XR studies over the last decade, with the XR technologies used for communication (N = 24), dissemination (N = 23), educational/training (N = 21), and decision-making (N = 10). Our results indicate the need to establish clearer guidelines for aligning science communication and to create more possibilities to publish peer-reviewed research in.