Deep eutectic solvents (DES) are gaining interest as eco-friendly alternatives for extracting bioactive compounds, but their environmental benefits remain unclear and need further evaluation. In this work, a case study of total polyphenols (TPC) extraction from spent coffee grounds (SCG) was environmentally evaluated using life cycle assessment (LCA). First, the most convenient extraction time (1, 10, 20, or 40 min) for water and acetone 20 % from an environmental perspective was identified. Second, a comparison of different solvents—DES (cholinechloride-1,6-hexanediol), water, and ethanol 20 %—under their optimal extraction yield conditions was performed using literature data. Results from the first study revealed that the environmentally optimal extraction time (10 min) was not the one leading to the highest yield. The main contributors to the impacts were the use of acetone and electricity consumption.
For the second study, DES performed worse in all studied environmental impact categories compared to both ethanol 20 % and water. Ethanol 20 % was the better option compared to water due to its higher extraction yield (9.2 mg vs. 6.5 mg TPC/g SCG, respectively). The environmental impacts associated with the DES system were primarily attributed to the DES preparation step, which requires virgin raw materials (e.g., dimethyl hexanediol), and the adsorption stage involving the use of resins. A sensitivity analysis was also conducted by optimizing the DES system to the best possible described conditions (90 % reuse of DES and maximum reduction of the macroporous resin used to adsorb the TPC after extraction). Nevertheless, the DES system still performed worse than water or ethanol 20 % systems, in 11 out of 16 impact categories.
The study highlights the importance to consider environmental impacts and yield when optimizing extraction processes, especially at the laboratory scale, as the insights gained are valuable for improving eco-efficiency on an industrial scale., This work was supported by the Spanish Ministry of Science and Innovation to the project KAIROS-BIOCIR (PID2019-104925RB-C32). The first author also appreciates the support (2021FI SDUR 00130) from the Secretariat for Universities and Research of the Ministry of Business and Knowledge of the Government of Catalonia and the European Social Fund. CRediT authorsh

Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are bipartite and in which the undirected and directed degrees are one. The best graphs, in terms of the number of vertices, are presented for small diameters. Moreover, two infinite families of such graphs with diameter k and number of vertices of the order of 2k/2 are proposed, one of them being totally regular (1,1)-mixed graphs. In addition, we present two more infinite families called chordal ring and chordal double ring mixed graphs, which are bipartite and related to tessellations of the plane. Finally, we give an upper bound that improves the Moore bound for bipartite mixed graphs for r = z = 1., The research of C. Dalfó and M. A. Fiol has been supported by AGAUR from the Catalan Government underproject 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. There search of M. A. Fiol was also supported by a grant from the Universitat Politècnica de Catalunya with referencesAGRUPS-2022 and AGRUPS-2023

The k-token graph 𝐹𝑘(𝐺) of a graph G is the graph whose vertices are the K-subsets of vertices from G, two of which being adjacent whenever their symmetric difference is a pair of adjacent vertices in G. In this paper, we propose a general method to find the spectrum and eigenspaces of the k-token graph 𝐹𝑘(𝐶𝑛)of a cycle Cn. The method is based on the theory of lift graphs and the recently introduced theory of over-lifts. In the case of k=2, we use continuous fractions to derive the spectrum and eigenspaces of the 2-token graph of Cn., This research has been supported by AGAUR, Catalonia from the Catalan Government under project 2021SGR00434 and MICINN, Spain from the Spanish Government under project PID2020-115442RB-I00. The research of M.A. Fiol was also supported by a grant from the Universitat Politècnica de Catalunya, Catalonia with references AGRUPS-2022 and AGRUPS-2023.

Con el presente estudio recogemos datos, ordenamos y clasificamos las producciones teatrales, las representaciones, los autores, los directores, actores y creadores en diversas áreas escénicas de las aulas de teatro universitarias gallegas a lo largo de 25 años. Asimismo, pretendemos dar cuenta de los festivales y muestras de teatro que han organizado las aulas a lo largo de este tiempo, desde su creación como tales grupos institucionales hasta hoy. En los años 90, el teatro ligado a las instituciones universitarias presenta un auge a nivel de infraestructura, producciones teatrales, número de
representaciones y organización de muestras de teatro universitario con la aparición de las aulas de teatro, que suponen un modelo diferenciado dentro del teatro universitario de la Península Ibérica como compañías de producción y representaciones, además de núcleos de formación teatral. Con esta perspectiva, planteamos un trabajo de ‘historiografía dramática’ desde el punto de vista de la representación y de las compañías (y el conjunto de autores-actores-creadores teatrales) que las llevan a cabo. En conclusión, con la presente tesis de doctorado queremos demostrar que hay un sistema teatral universitario gallego que a lo largo de 25 años ha constituido un modelo diferenciado e importante dentro del teatro universitario español y que con sus muestras y festivales ha programado gran parte del teatro universitario estatal desde el año 1990 al 2015., With this study we collect data, sort and classify the theatre productions, performances, authors, directors, actors and creators on the different scenic areas of the Galician University Theatre Workshops during 25 years. Likewise, we aim to present the theatre festivals and shows that these workshops have organized during all this time since their creation as institutional groups until today. In the 90’s, the theatre linked to university institutions increased its infrastructure, theatre productions, number of performances and the organization of University Theatre festivals because of the emergence of the Theatre Workshops, which represent a differentiated model within the university theatre of the Iberian Peninsula working as production companies with their own theatre performances besides as theatre training centers. With this perspective we consider a “dramatic historiography” work from the point of view of the performances and the companies (and the combination of theatre authorsactors-creators) that carry them out. In conclusion, with this doctoral thesis we want to prove that there is a university theatre system in Galicia that throughout 25 years has established a differentiated and important model within the Spanish university theatre and that with its shows and festivals it has programmed much of the state-owned university theatre from 1990 to 2015.

For a graph G, its k-th graph power Gk is constructed by placing an edge between two vertices if they are within distance k. We consider the problem of deriving upper bounds on the Shannon capacity of graph powers by using spectral graph theory and linear optimization methods. First, we use the so-called ratio-type bound to provide an alternative and spectral proof of a result by Lovasz [ IEEE Trans. Inform. Theory 1979], which states that, for a regular graph, the Hoffman ratio bound on the independence number is also an upper bound on the Lovasz theta number and, hence, also on the Shannon capacity. In fact, we show that Lovasz’ result holds in the more general context of graph powers. Secondly, we derive another bound on the Shannon capacity of graph powers, the so-called rank-type bound, which depends on a new family of polynomials that can be computed by running a simple algorithm. Lastly, we provide several computational xperiments that demonstrate the sharpness of the two proposed algebraic bounds. As a by-product, when these two new algebraic bounds are tight, they can be used to easily derive the exact values of the Lovasz theta number which relies on solving an SDP) and the Shannon capacity (which is not known to be computable) of the corresponding graph power., Abiad is supported by NWO (Dutch Research Council) through the grants VI.Vidi.213.085 and OCENW.KLEIN.475. C. Dalfo and M. A. Fiol are funded by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. M. A. Fiol’s research is also supported by a grant from the Universitat Politecnica de Catalunya, reference AGRUPS-2025. The authors thank Luuk Reijnders for his support with Sagemath. The first author thanks Jeroen Zuiddam for inspiring discussions on the topic.

The growing demand for renewable energy sources, particularly solar photovoltaic (PV) technology, poses a significant challenge to agricultural land use, creating a conflict over land allocation critical for food production and energy generation. This study addresses this issue by proposing a real options model to evaluate the timing of PV plant installation on agricultural land, incorporating uncertainties related to electricity prices and PV technology costs. This methodology has the advantage of incorporating flexibility in decision-making and the consideration of irreversibility, making it especially suitable for analyzing land-use changes. The model is applied to a case study in Spain, analyzing 134 crop types across 15 regions, to estimate the optimal timing for farmers to switch from traditional agriculture to solar PV installations. The findings indicate that the cost of PV technology is the primary driver of this transition, with the model predicting that PV installations will become more profitable than agriculture within the next 20 years, particularly in southern Spain, where higher solar irradiance accelerates the process. Furthermore, the study highlights the need for differentiated regulatory policies, with stricter measures recommended for regions with higher land-use change risk. This research contributes to the literature by providing a tool for assessing land-use conflicts between agriculture and renewable energy, offering insights for policymakers, investors, and academics., The authors acknowledge the support and funding from ANID-Subdireccion de Capital Humano/Doctorado Nacional/2021–21210320, Conicyt-Fondecyt 1221943, Conicyt-FONDAP 1522A0006 (SERC Chile), MCIU/AEI&ERDF-EU PID2022-140546OB-I00 and Departament de Recerca i Universitat de la Generalitat de Catalunya 2021SGR00355.

The vertices of a k-token graph of a graph G correspond to k indistinguishable tokens placed on k different vertices of G. Changing some conditions on both the nature of the tokens and the number of tokens allowed in each vertex of G, we define a generalization of token graphs, which we call generalized token graphs or simply supertoken graphs, which have different applications. Depending on the above conditions, different families of graphs (such as the Cartesian k-th power of G by itself) are obtained, and we present some of their properties, including order, size, and connectivity. © 2026, University of Nis. All rights reserved., 2020 Mathematics Subject Classification. Primary 05C15; Secondary 05C10, 05C50. Keywords. Token graph, Cartesian product, connectivity. Received: 27 July 2025; Revised: 13 October 2025; Accepted: 19 November 2025 Communicated by Paola Bonacini The research of the first and last authors has been supported by National Natural Science Foundation of China (No. 12471334, No. 12131013), and Shaanxi Fundamental Science Research Project for Mathematics and Physics (No. 22JSZ009). The research of the second and third authors was funded by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The third author\u2019s research is also supported by a grant from the Universitat Polit\u00E8cnica de Catalunya, reference AGRUPS-2024. The fourth author\u2019s research is supported by grants PID2023-150725NB-I00 funded by MICIU/AEI/10.13039/501100011033PID2023-150725NB-I00 and Gen. Cat. DGR 2017SGR1336. * Corresponding author: Cristina Dalf\u00F3 Email addresses: songxd@mail.nwpu.edu.cn (Xiaodi Song), cristina.dalfo@udl.cat (Cristina Dalf\u00F3), miguel.angel.fiol@upc.edu (Miquel \u00C0ngel Fiol), merce.mora@upc.edu (Merc\u00E8 Mora), sgzhang@nwpu.edu.cn (Shenggui Zhang) ORCID iDs: https://orcid.org/0000-0002-6859-7443 (Xiaodi Song), https://orcid.org/0000-0002-8438-9353 (Cristina Dalf\u00F3), https://orcid.org/0000-0003-1337-4952 (Miquel \u00C0ngel Fiol), https://orcid.org/0000-0001-6923-0320 (Merc\u00E8 Mora), https://orcid.org/0000-0002-9596-0826 (Shenggui Zhang)

Deep eutectic solvents (DES) are gaining interest as eco-friendly alternatives for extracting bioactive compounds, but their environmental benefits remain unclear and need further evaluation. In this work, a case study of total polyphenols (TPC) extraction from spent coffee grounds (SCG) was environmentally evaluated using life cycle assessment (LCA). First, the most convenient extraction time (1, 10, 20, or 40 min) for water and acetone 20 % from an environmental perspective was identified. Second, a comparison of different solvents—DES (cholinechloride-1,6-hexanediol), water, and ethanol 20 %—under their optimal extraction yield conditions was performed using literature data. Results from the first study revealed that the environmentally optimal extraction time (10 min) was not the one leading to the highest yield. The main contributors to the impacts were the use of acetone and electricity consumption.
For the second study, DES performed worse in all studied environmental impact categories compared to both ethanol 20 % and water. Ethanol 20 % was the better option compared to water due to its higher extraction yield (9.2 mg vs. 6.5 mg TPC/g SCG, respectively). The environmental impacts associated with the DES system were primarily attributed to the DES preparation step, which requires virgin raw materials (e.g., dimethyl hexanediol), and the adsorption stage involving the use of resins. A sensitivity analysis was also conducted by optimizing the DES system to the best possible described conditions (90 % reuse of DES and maximum reduction of the macroporous resin used to adsorb the TPC after extraction). Nevertheless, the DES system still performed worse than water or ethanol 20 % systems, in 11 out of 16 impact categories.
The study highlights the importance to consider environmental impacts and yield when optimizing extraction processes, especially at the laboratory scale, as the insights gained are valuable for improving eco-efficiency on an industrial scale., This work was supported by the Spanish Ministry of Science and Innovation to the project KAIROS-BIOCIR (PID2019-104925RB-C32). The first author also appreciates the support (2021FI SDUR 00130) from the Secretariat for Universities and Research of the Ministry of Business and Knowledge of the Government of Catalonia and the European Social Fund. CRediT authorsh

Mixed graphs can be seen as digraphs that have both arcs and edges (or digons, that is, two opposite arcs). In this paper, we consider the case where such graphs are bipartite and in which the undirected and directed degrees are one. The best graphs, in terms of the number of vertices, are presented for small diameters. Moreover, two infinite families of such graphs with diameter k and number of vertices of the order of 2k/2 are proposed, one of them being totally regular (1,1)-mixed graphs. In addition, we present two more infinite families called chordal ring and chordal double ring mixed graphs, which are bipartite and related to tessellations of the plane. Finally, we give an upper bound that improves the Moore bound for bipartite mixed graphs for r = z = 1., The research of C. Dalfó and M. A. Fiol has been supported by AGAUR from the Catalan Government underproject 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. There search of M. A. Fiol was also supported by a grant from the Universitat Politècnica de Catalunya with referencesAGRUPS-2022 and AGRUPS-2023

The k-token graph 𝐹𝑘(𝐺) of a graph G is the graph whose vertices are the K-subsets of vertices from G, two of which being adjacent whenever their symmetric difference is a pair of adjacent vertices in G. In this paper, we propose a general method to find the spectrum and eigenspaces of the k-token graph 𝐹𝑘(𝐶𝑛)of a cycle Cn. The method is based on the theory of lift graphs and the recently introduced theory of over-lifts. In the case of k=2, we use continuous fractions to derive the spectrum and eigenspaces of the 2-token graph of Cn., This research has been supported by AGAUR, Catalonia from the Catalan Government under project 2021SGR00434 and MICINN, Spain from the Spanish Government under project PID2020-115442RB-I00. The research of M.A. Fiol was also supported by a grant from the Universitat Politècnica de Catalunya, Catalonia with references AGRUPS-2022 and AGRUPS-2023.

In this paper, we construct two infinite families of graphs G(d, c) and G+(d, c), where, in both cases, a vertex label is x1x2 . . . xc with xi ∈ {1, 2, . . . , d}. We provide a tight lower bound on the metric dimension of G+(d, c). Moreover, we give the definition and properties of the supertoken graphs, a generalization of the well-known token graphs.
Finally, we provide an upper bound on the metric dimension of supertoken graphs., The second and third authors’ research has been supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The research of the third author was also supported by a grant from the Universitat Politècnica de Catalunya with references AGRUPS-2024.

Plectic points were introduced by Fornea and Gehrmann [Adv. Math. 414 (2023)] as certain tensor products of local points on elliptic curves over arbitrary number fields . They are constructed in rank -situations, and they conjecturally come from -adic regulators of basis of the Mordell-Weil group defined over dihedral extensions of.
In this article we define anticyclotomic -adic L-functions with variables of type weight and level attached to a family of overconvergent modular symbols defined over totally real fields and a quadratic extension . Their restriction to the weight space provides Hida-Rankin -adic L-functions.
If such a family passes through an overconvergent modular symbol attached to a modular elliptic curve , we obtain a -adic Gross-Zagier formula that computes higher derivatives of such Hida-Rankin -adic L-functions in terms of plectic points. This result generalizes that of Bertolini and Darmon [Ann. of Math. (2) 170 (2009), pp. 343–370], which has been key to the recent approach towards the algebraicity of Darmon points., This project had received funding from the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation programme (grant agreement No. 682152). The second author was also funded by Ministerio de Ciencia e innovaci\u00F3n, project PID2022-137605NB-I00, and this paper was part of the R&D+i project PID2021-124613OB-I00 funded by MI-CIU/AEI/10.13039/501100011033 and FEDER, EU. We would also like to thank Lennart Gehrmann for all his helpful remarks and comments.Received by the editors April 21, 2022, and, in revised form, September 21, 2023, April 12, 2024, and January 15, 2025. 2020 Mathematics Subject Classification. Primary 11G05, 11G40, 11S40; Secondary 11F85. Projects PID2022-137605NB-I00 and PID2021-124613OB-I00. This project had received funding from the European Research Council (ERC) under the European Union\u2019s Horizon 2020 research and innovation programme (grant agreement No. 682152). The second author was also funded by Ministerio de Ciencia e innovaci\u00F3n, project PID2022-137605NB-I00, and this paper was part of the R&D+i project PID2021-124613OB-I00 funded by MI-CIU/AEI/10.13039/501100011033 and FEDER, EU.

We introduce and study a new family of circulant digraphs associated with the cyclic group Zn, obtained by restricting admissible combinations of two generators a and b to three coordinate sectors. The resulting distance-like function differs from the standard directed distance in circulant digraphs and gives rise to new geometric and combinatorial phenomena. Using planar lattice representations and periodic tessellations, we analyze the growth of reachable sets and derive Moore-type upper bounds for the corresponding order/diameter problem. We construct explicit infinite families of three-quarters circulant structures with the prescribed diameter and provide lattice-based methods for determining admissible generator pairs. Separate constructions are obtained for even and odd diameters. In addition, computational experiments for small and moderate orders suggest improved families for even diameters and motivate a conjectural asymptotic formula for the maximum attainable order. The paper highlights the interplay between constrained lattice representations, periodic tilings, and extremal problems for circulant networks., This research has been supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00.

In this paper, we first give a new result characterizing the strongly connected digraphs with a diameter equal to that of their line digraphs. Then we introduce the concepts of the inner diameter and inner radius of a digraph and study their behaviors in its iterated line digraphs. Furthermore, we provide a method to characterize sequences of integers (corresponding to the inner diameter or the number of vertices of a digraph and its iterated line digraphs) that satisfy some conditions. Among other examples, we apply the method to the cyclic Kautz digraphs, square-free digraphs, and the subdigraphs of De Bruijn digraphs. Finally, we present some tables with new sequences that do not belong to The On-Line Encyclopedia of Integer Sequences., This research has been supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The research of M. A. Fiol was also supported by a grant from the Universitat Polit\u00E8cnica de Catalunya with references AGRUPS-2022 and AGRUPS-2023. The research of D. Z\u00E1vack\u00E1 was supported by G-24-158-00 and VEGA 1/0437/23.

Alternative protein sources (APSs) have emerged as a potentially healthy and, presumably, environmentally sustainable solution for meeting future food demand. Here we develop a new complex nutrient profile model to assess the nutritional quality of protein-rich foods, which, concurrently, allows to evaluate their environmental implications efficiently through the application of life cycle assessment (LCA). The development of the index was guided by the identification of priority nutrients in APSs and main deficiencies of similar models, which gave rise to the ‘quality Nutrient Rich Food 1.10.2’ (qNRF1.10.2). This model is the first nutrient profile system that combines various essential nutrients and a protein quality scoring system, namely Digestible Indispensable Amino Acid Score (DIAAS). From a nutritional perspective, its accuracy was proven and its application identified animal products as the most nutritionally complete food group, surpassing plant-based alternatives. However, when using the index as functional unit in LCA of protein-rich foods, we discovered that seeds, nuts, and mixtures of vegetable foods reported the lowest environmental impacts as a function of their nutrient density. Some exceptions were found for algae or insects, which performed worse than animal-derived foods in terms of resources consumption, or for cereals, which shown an important water deprivation potential. These results suggest that we should find a trade-off between the production of emerging and conventional foodstuffs, and that main environmental issues of each region should condition the location of production systems., This work was supported by the Spanish Ministry of Science and Innovation through the KAIROS-BIOCIR project (PID2019-104925RB) (AEO/FEDER, UE). Ana Fernández-Ríos thanks the Ministry of Science and Innovation of Spanish Government for their financial support via the research fellowship RE2020-094029.

This study examines the impact on health outcomes of the social energy tariff, a policy tool in Spain designed to alleviate energy poverty. Energy poverty—being unable to afford adequate heating, cooling, or other energy needs— is linked to poor physical and mental health. Using a recursive bivariate probit model, we analyze data from the 2022 Spanish Living Conditions Survey, focusing on the health implications of energy poverty, measured through inadequate home temperature and delayed bill payments. The results show that, while the social energy tariff moderately reduces energy poverty —with only a 1 %–2 % decrease, its impact on improving health outcomes remains limited. The average treatment effect on the treated suggests that individuals experiencing energy poverty are significantly more likely to report poor physical and mental health, with a 7 %–23 % decrease in the likelihood of reporting good health. Our findings indicate that, although the social energy tariff provides some financial relief, structural solutions such as energy efficiency improvements and increased access to renewable energy are needed to address the broader health impacts of energy poverty. The study offers policy recommendations to enhance both energy access and public health, emphasizing the importance of integrating health considerations into energy poverty interventions., The authors acknowledge support from project PID2022-140546OB-I00, funded by MCIU/AEI/10.13039/501100011033 and ERDF, EU; from project 2021SGR00355, funded by the Departament de Recerca i Universitat de la Generalitat de Catalunya; and from the Chair of Energy Sustainability (IEB, Universitat de Barcelona).

This research paper presents a methodology consisting of an algorithm and a workflow for finding abandoned dogs in natural surroundings. We propose a temporal-contextual methodology for identifying abandoned pets in public areas. This involves employing a temporal rule alongside context-sensitive object identification, whereby dog bounding boxes are deliberately expanded to encompass proximate visual indicators suggestive of abandonment. The proposed approach uses object detection techniques, trajectory analysis, and image segmentation to quickly differentiate between abandoned and owned dogs. The research addresses key challenges, such as data scarcity and the complexity of distinguishing between abandoned and accompanied dogs. To address the issue of sufficient and adequate training corpus to identify an abandoned dog, the research article employs single-channel image augmentation methods that improve model recall and precision by 4%.
Several object detection algorithms were evaluated, and our findings indicate that single-stage detectors like YOLOv8 achieved a better trade-off between classification performance and speed for detecting abandoned dogs compared to multi-stage detectors like Faster R-CNN, reaching a mean average precision up to 86% and an inference time of 0.3 ms per frame. This research study contributes to animal welfare, biodiversity conservation, and public safety by providing a scalable solution for monitoring abandoned animals in diverse environments.
The findings demonstrate the impact of object detection techniques on improving the generalization of deep learning models for real-world applications., This work has been supported by the Generalitat de Catalunya for the financial support to the primary author, beneficiary of a pre-doctoral grant funded under the Program contract between the Administration of the Generalitat of Catalonia, through the Department of Territory and Sustainability and the Department of Business and Knowledge, and the International Center for Numerical Methods in Engineering (CIMNE), for the period 2020-2023. This research was also been developed within the PIKSEL project, “Portal for the integration of knowledge for a sustainable ecosystems and land management” funded by Generalitat de Catalunya, through the Department of Territory and Sustainability and the Department of Climate Action. The authors also acknowledge the financial support through the Severo Ochoa Centers of Excellence Program (CEX 2018- 000797-S) funded by MCIN/AEI/10.13039/501100011033

Given a graph G = (V, E) on n vertices and an integer k between 1 and n-1, the k-token graph Fk(G) has vertices representing the k-subsets of V, and two vertices are adjacent if their symmetric difference is the two end-vertices of an edge in E. Using the theory of Markov chains of random walks and the interchange process, it was proved that the algebraic connectivities (second smallest Laplacian eigenvalues) of G and Fk(G) coincide, but a combinatorial/algebraic proof has been shown elusive. In this paper, we use the latter approach and prove that such equality holds for different new classes of graphs under perturbations, such as extended cycles, extended complete bipartite graphs, kite graphs, and graphs with a cut clique. Kite graphs are formed by a graph (head) with several paths (tail) rooted at the same vertex and with exciting properties. For instance, we show that the different eigenvalues of a kite graph are also eigenvalues of its perturbed graph obtained by adding edges. Moreover, as a particular case of one of our theorems, we generalize a recent result of Barik and Verma (2024) about graphs with a cut vertex of degree n-1. Along the way, we give conditions under which the perturbed graph G + uv, with uv is an element of E, has the same algebraic connectivity as G., This research has been supported by National Natural Science Foundation of China (No. 12471334, No. 12131013), and Shaanxi Fundamental Science Research Project for Mathematics and Physics (No. 22JSZ009). C. Dalfó and M. A. Fiol are funded by AGAUR, Spain from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. M. A. Fiol’s research is also supported by a grant from the Universitat Politècnica de Catalunya, reference AGRUPS-2024.

Hospitals discharge wastewater containing toxic pollutants that pose risks to human health and the environment if not properly treated. Therefore, effective treatment techniques are essential. Although various reviews have explored hospital wastewater treatment (HWWT) methods, few have comprehensively assessed their sustainability-including technical, environmental, economic, and social aspects. This paper reviews the literature on these dimensions and identifies critical research gaps. Technically, the combination of biological and tertiary techniques can achieve removal efficiencies between 60% and 99% for emerging contaminants. Environmentally, electricity consumption is a major concern, ranging from 0.2 to 3 kWh/m3, depending on the technique. Economically, costs rise with energy-intensive methods; ultraviolet disinfection operates at 0.016 <euro>/m3, while Fenton treatment reaches 23.38 <euro>/m3. No dedicated social assessments exist for HWWT; therefore, municipal wastewater studies were used as references. This paper proposes public health-related social indicators tailored for HWWT. Two key research gaps are identified: the lack of integrated sustainability and social assessments and limited comparability across studies. This review adapts the life cycle sustainability assessment framework to HWWT and offers recommendations for improved comparability and targeted future research. Addressing these gaps will support more holistic evaluations and guide effective and informed decision-making in hospital wastewater management., 1-This research was funded by the Spanish Ministry of Science and Innovation for the KAIROS-BIOCIR project (PID2019-104925RB-C32). This research was also funded by the Sustainable Wastewater Treatment for Hospitals/SWaTH project (618540-EPP-1-2020-LB-EPPKA2-GBHE-JP), co-funded by the Erasmus Plus Programme of the European Commission. The project is carried out under the centralized activity \u201CCapacity-Building in the Field of Higher Education\u201D/AC\u2013A02\u20132019\u2013CBHE. 2-The authors would like to acknowledge the Spanish Ministry of Science and Innovation for its support through the KAIROS-BIOCIR project (PID2019-104925RB-C32). The authors also acknowledge the Sustainable Wastewater Treatment for Hospitals (SWaTH) project (618540-EPP-1-2020-LB-EPPKA2-GBHE-JP) for its continuous support throughout this research. SWaTH is a capacity-building project co-funded by the Erasmus+ Programme of the European Commission. Without their generous support, this research would not have been possible.

El EEES comporta la construcción de un nuevo espacio europeo compartido de educación superior en el que la formación que se ofrece está basada y diseñada por competencias. Es este un cambio sustantivo que comporta, a su vez, diversos cambios importantes en la forma de entender, de diseñar y de impartir la formación. Entre ellos, la forma cómo se evalúa es sin duda uno de los más cruciales, por lo que representa en el proceso de aprendizaje y por las dificultades que comporta para profesores y
alumnos.
En este artículo, se presentan resultados de una investigación sobre la evaluación por competencias en la universidad. Se ha preguntado a directores de centros, profesores, empleadores y alumnos de 7 universidades y 4 titulaciones sobre la implantación de los programas por competencias. Presentamos el análisis de cuál es la opinión de los estudiantes de ingeniería sobre cómo se les evalúa y la utilidad que dan a cada estrategia de evaluación. Así mismo, se comparan estos resultados con los de otras titulaciones universitarias.

Alternative protein sources (APSs) have emerged as a potentially healthy and, presumably, environmentally sustainable solution for meeting future food demand. Here we develop a new complex nutrient profile model to assess the nutritional quality of protein-rich foods, which, concurrently, allows to evaluate their environmental implications efficiently through the application of life cycle assessment (LCA). The development of the index was guided by the identification of priority nutrients in APSs and main deficiencies of similar models, which gave rise to the ‘quality Nutrient Rich Food 1.10.2’ (qNRF1.10.2). This model is the first nutrient profile system that combines various essential nutrients and a protein quality scoring system, namely Digestible Indispensable Amino Acid Score (DIAAS). From a nutritional perspective, its accuracy was proven and its application identified animal products as the most nutritionally complete food group, surpassing plant-based alternatives. However, when using the index as functional unit in LCA of protein-rich foods, we discovered that seeds, nuts, and mixtures of vegetable foods reported the lowest environmental impacts as a function of their nutrient density. Some exceptions were found for algae or insects, which performed worse than animal-derived foods in terms of resources consumption, or for cereals, which shown an important water deprivation potential. These results suggest that we should find a trade-off between the production of emerging and conventional foodstuffs, and that main environmental issues of each region should condition the location of production systems., This work was supported by the Spanish Ministry of Science and Innovation through the KAIROS-BIOCIR project (PID2019-104925RB) (AEO/FEDER, UE). Ana Fernández-Ríos thanks the Ministry of Science and Innovation of Spanish Government for their financial support via the research fellowship RE2020-094029.

In this paper, we first give a new result characterizing the strongly connected digraphs with a diameter equal to that of their line digraphs. Then we introduce the concepts of the inner diameter and inner radius of a digraph and study their behaviors in its iterated line digraphs. Furthermore, we provide a method to characterize sequences of integers (corresponding to the inner diameter or the number of vertices of a digraph and its iterated line digraphs) that satisfy some conditions. Among other examples, we apply the method to the cyclic Kautz digraphs, square-free digraphs, and the subdigraphs of De Bruijn digraphs. Finally, we present some tables with new sequences that do not belong to The On-Line Encyclopedia of Integer Sequences., This research has been supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The research of M. A. Fiol was also supported by a grant from the Universitat Polit\u00E8cnica de Catalunya with references AGRUPS-2022 and AGRUPS-2023. The research of D. Z\u00E1vack\u00E1 was supported by G-24-158-00 and VEGA 1/0437/23.

Hospitals discharge wastewater containing toxic pollutants that pose risks to human health and the environment if not properly treated. Therefore, effective treatment techniques are essential. Although various reviews have explored hospital wastewater treatment (HWWT) methods, few have comprehensively assessed their sustainability-including technical, environmental, economic, and social aspects. This paper reviews the literature on these dimensions and identifies critical research gaps. Technically, the combination of biological and tertiary techniques can achieve removal efficiencies between 60% and 99% for emerging contaminants. Environmentally, electricity consumption is a major concern, ranging from 0.2 to 3 kWh/m3, depending on the technique. Economically, costs rise with energy-intensive methods; ultraviolet disinfection operates at 0.016 <euro>/m3, while Fenton treatment reaches 23.38 <euro>/m3. No dedicated social assessments exist for HWWT; therefore, municipal wastewater studies were used as references. This paper proposes public health-related social indicators tailored for HWWT. Two key research gaps are identified: the lack of integrated sustainability and social assessments and limited comparability across studies. This review adapts the life cycle sustainability assessment framework to HWWT and offers recommendations for improved comparability and targeted future research. Addressing these gaps will support more holistic evaluations and guide effective and informed decision-making in hospital wastewater management., 1-This research was funded by the Spanish Ministry of Science and Innovation for the KAIROS-BIOCIR project (PID2019-104925RB-C32). This research was also funded by the Sustainable Wastewater Treatment for Hospitals/SWaTH project (618540-EPP-1-2020-LB-EPPKA2-GBHE-JP), co-funded by the Erasmus Plus Programme of the European Commission. The project is carried out under the centralized activity \u201CCapacity-Building in the Field of Higher Education\u201D/AC\u2013A02\u20132019\u2013CBHE. 2-The authors would like to acknowledge the Spanish Ministry of Science and Innovation for its support through the KAIROS-BIOCIR project (PID2019-104925RB-C32). The authors also acknowledge the Sustainable Wastewater Treatment for Hospitals (SWaTH) project (618540-EPP-1-2020-LB-EPPKA2-GBHE-JP) for its continuous support throughout this research. SWaTH is a capacity-building project co-funded by the Erasmus+ Programme of the European Commission. Without their generous support, this research would not have been possible.

This study examines the impact on health outcomes of the social energy tariff, a policy tool in Spain designed to alleviate energy poverty. Energy poverty—being unable to afford adequate heating, cooling, or other energy needs— is linked to poor physical and mental health. Using a recursive bivariate probit model, we analyze data from the 2022 Spanish Living Conditions Survey, focusing on the health implications of energy poverty, measured through inadequate home temperature and delayed bill payments. The results show that, while the social energy tariff moderately reduces energy poverty —with only a 1 %–2 % decrease, its impact on improving health outcomes remains limited. The average treatment effect on the treated suggests that individuals experiencing energy poverty are significantly more likely to report poor physical and mental health, with a 7 %–23 % decrease in the likelihood of reporting good health. Our findings indicate that, although the social energy tariff provides some financial relief, structural solutions such as energy efficiency improvements and increased access to renewable energy are needed to address the broader health impacts of energy poverty. The study offers policy recommendations to enhance both energy access and public health, emphasizing the importance of integrating health considerations into energy poverty interventions., The authors acknowledge support from project PID2022-140546OB-I00, funded by MCIU/AEI/10.13039/501100011033 and ERDF, EU; from project 2021SGR00355, funded by the Departament de Recerca i Universitat de la Generalitat de Catalunya; and from the Chair of Energy Sustainability (IEB, Universitat de Barcelona).

The growing demand for renewable energy sources, particularly solar photovoltaic (PV) technology, poses a significant challenge to agricultural land use, creating a conflict over land allocation critical for food production and energy generation. This study addresses this issue by proposing a real options model to evaluate the timing of PV plant installation on agricultural land, incorporating uncertainties related to electricity prices and PV technology costs. This methodology has the advantage of incorporating flexibility in decision-making and the consideration of irreversibility, making it especially suitable for analyzing land-use changes. The model is applied to a case study in Spain, analyzing 134 crop types across 15 regions, to estimate the optimal timing for farmers to switch from traditional agriculture to solar PV installations. The findings indicate that the cost of PV technology is the primary driver of this transition, with the model predicting that PV installations will become more profitable than agriculture within the next 20 years, particularly in southern Spain, where higher solar irradiance accelerates the process. Furthermore, the study highlights the need for differentiated regulatory policies, with stricter measures recommended for regions with higher land-use change risk. This research contributes to the literature by providing a tool for assessing land-use conflicts between agriculture and renewable energy, offering insights for policymakers, investors, and academics., The authors acknowledge the support and funding from ANID-Subdireccion de Capital Humano/Doctorado Nacional/2021–21210320, Conicyt-Fondecyt 1221943, Conicyt-FONDAP 1522A0006 (SERC Chile), MCIU/AEI&ERDF-EU PID2022-140546OB-I00 and Departament de Recerca i Universitat de la Generalitat de Catalunya 2021SGR00355.

For a graph G, its k-th graph power Gk is constructed by placing an edge between two vertices if they are within distance k. We consider the problem of deriving upper bounds on the Shannon capacity of graph powers by using spectral graph theory and linear optimization methods. First, we use the so-called ratio-type bound to provide an alternative and spectral proof of a result by Lovasz [ IEEE Trans. Inform. Theory 1979], which states that, for a regular graph, the Hoffman ratio bound on the independence number is also an upper bound on the Lovasz theta number and, hence, also on the Shannon capacity. In fact, we show that Lovasz’ result holds in the more general context of graph powers. Secondly, we derive another bound on the Shannon capacity of graph powers, the so-called rank-type bound, which depends on a new family of polynomials that can be computed by running a simple algorithm. Lastly, we provide several computational xperiments that demonstrate the sharpness of the two proposed algebraic bounds. As a by-product, when these two new algebraic bounds are tight, they can be used to easily derive the exact values of the Lovasz theta number which relies on solving an SDP) and the Shannon capacity (which is not known to be computable) of the corresponding graph power., Abiad is supported by NWO (Dutch Research Council) through the grants VI.Vidi.213.085 and OCENW.KLEIN.475. C. Dalfo and M. A. Fiol are funded by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. M. A. Fiol’s research is also supported by a grant from the Universitat Politecnica de Catalunya, reference AGRUPS-2025. The authors thank Luuk Reijnders for his support with Sagemath. The first author thanks Jeroen Zuiddam for inspiring discussions on the topic.

The vertices of a k-token graph of a graph G correspond to k indistinguishable tokens placed on k different vertices of G. Changing some conditions on both the nature of the tokens and the number of tokens allowed in each vertex of G, we define a generalization of token graphs, which we call generalized token graphs or simply supertoken graphs, which have different applications. Depending on the above conditions, different families of graphs (such as the Cartesian k-th power of G by itself) are obtained, and we present some of their properties, including order, size, and connectivity. © 2026, University of Nis. All rights reserved., 2020 Mathematics Subject Classification. Primary 05C15; Secondary 05C10, 05C50. Keywords. Token graph, Cartesian product, connectivity. Received: 27 July 2025; Revised: 13 October 2025; Accepted: 19 November 2025 Communicated by Paola Bonacini The research of the first and last authors has been supported by National Natural Science Foundation of China (No. 12471334, No. 12131013), and Shaanxi Fundamental Science Research Project for Mathematics and Physics (No. 22JSZ009). The research of the second and third authors was funded by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The third author\u2019s research is also supported by a grant from the Universitat Polit\u00E8cnica de Catalunya, reference AGRUPS-2024. The fourth author\u2019s research is supported by grants PID2023-150725NB-I00 funded by MICIU/AEI/10.13039/501100011033PID2023-150725NB-I00 and Gen. Cat. DGR 2017SGR1336. * Corresponding author: Cristina Dalf\u00F3 Email addresses: songxd@mail.nwpu.edu.cn (Xiaodi Song), cristina.dalfo@udl.cat (Cristina Dalf\u00F3), miguel.angel.fiol@upc.edu (Miquel \u00C0ngel Fiol), merce.mora@upc.edu (Merc\u00E8 Mora), sgzhang@nwpu.edu.cn (Shenggui Zhang) ORCID iDs: https://orcid.org/0000-0002-6859-7443 (Xiaodi Song), https://orcid.org/0000-0002-8438-9353 (Cristina Dalf\u00F3), https://orcid.org/0000-0003-1337-4952 (Miquel \u00C0ngel Fiol), https://orcid.org/0000-0001-6923-0320 (Merc\u00E8 Mora), https://orcid.org/0000-0002-9596-0826 (Shenggui Zhang)

In this paper, we construct two infinite families of graphs G(d, c) and G+(d, c), where, in both cases, a vertex label is x1x2 . . . xc with xi ∈ {1, 2, . . . , d}. We provide a tight lower bound on the metric dimension of G+(d, c). Moreover, we give the definition and properties of the supertoken graphs, a generalization of the well-known token graphs.
Finally, we provide an upper bound on the metric dimension of supertoken graphs., The second and third authors’ research has been supported by AGAUR from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. The research of the third author was also supported by a grant from the Universitat Politècnica de Catalunya with references AGRUPS-2024.

Given a graph G = (V, E) on n vertices and an integer k between 1 and n-1, the k-token graph Fk(G) has vertices representing the k-subsets of V, and two vertices are adjacent if their symmetric difference is the two end-vertices of an edge in E. Using the theory of Markov chains of random walks and the interchange process, it was proved that the algebraic connectivities (second smallest Laplacian eigenvalues) of G and Fk(G) coincide, but a combinatorial/algebraic proof has been shown elusive. In this paper, we use the latter approach and prove that such equality holds for different new classes of graphs under perturbations, such as extended cycles, extended complete bipartite graphs, kite graphs, and graphs with a cut clique. Kite graphs are formed by a graph (head) with several paths (tail) rooted at the same vertex and with exciting properties. For instance, we show that the different eigenvalues of a kite graph are also eigenvalues of its perturbed graph obtained by adding edges. Moreover, as a particular case of one of our theorems, we generalize a recent result of Barik and Verma (2024) about graphs with a cut vertex of degree n-1. Along the way, we give conditions under which the perturbed graph G + uv, with uv is an element of E, has the same algebraic connectivity as G., This research has been supported by National Natural Science Foundation of China (No. 12471334, No. 12131013), and Shaanxi Fundamental Science Research Project for Mathematics and Physics (No. 22JSZ009). C. Dalfó and M. A. Fiol are funded by AGAUR, Spain from the Catalan Government under project 2021SGR00434 and MICINN from the Spanish Government under project PID2020-115442RB-I00. M. A. Fiol’s research is also supported by a grant from the Universitat Politècnica de Catalunya, reference AGRUPS-2024.

Trauma y tradición son dos conceptos con los que toda literatura del exilio y de la Shoah debe confrontarse –por la naturaleza violenta de las condiciones históricas que son su razón de ser y por la orfandad cultural implicada–. Suponen así serios desafíos para sus autores y autoras. Esta problemática se agudiza en los intentos del exilio español y alemán de inscribirse en una tradición literaria que otorgue un pasado a la propia ubicación extraterritorial. La marcada tendencia de la literatura del exilio y de los supervivientes hacia una escritura memorística se puede vincular así con la difícil relación entre trauma histórico y tradición literaria. Para afrontar esta temática, mi contribución examina una serie de genealogías literarias en textos alemanes y españoles, elaboradas a partir de las experiencias traumáticas de los años 1930 y 1940 con el fin de resignificar la propia producción literaria.

Coordinación general de la edición crítica de la 'Parte XX' de las comedias de Lope de Vega junto a Daniel Fernández. Edición perteneciente al proyecto editorial del Grupo PROLOPE (UAB), realizada siguiendo los criterios de edición del Grupo PROLOPE (https://prolope.uab.cat/obras/criterios_y_materiales_para_la_edicion.html). El volumen incluye las siguientes ediciones:
La discreta venganza (Edición de Manuel Piqueras Flores y Blanca Santos de la Morena)
Lo cierto por lo dudoso (Edición de Salomé Vuelta)
Pobreza no es vileza (Edición de Federica Cappelli)
Arauco domado (Edición de José Enrique Laplana Gil)
La ventura sin buscalla (Edición de Daniele Crivellari)
El valiente céspedes (Edición de Isabel Hernando Morata)
El hombre, por su palabra (Edición de Santiago Restrepo Ramírez)
Roma, abrasada (Edición de Victoriano Roncero López)
Virtud, pobreza y mujer (Edición de Daniel Fernández Rodríguez)
El rey sin reino (Edición de Francesca Leonetti y Oana Andreia Sambrian)
El mejor mozo de España (Edición de Guillermo Gómez Sánchez-Ferrer)
El marido más firme (Edición de Clara Monzó Ribes)

The lipase B from Candida antarctica was immobilized on octyl-agarose using low and high (one that saturated the support surface with enzyme) loadings. Then, both biocatalysts were aminated, and the aminated and non-aminated biocatalysts were used in further experiments. The enzyme activity was determined using substrates with different structures. The modification of the four biocatalysts with poly (ethylene-alt-maleic anhydride) revealed that only a marginal covalent reaction occurs. That way, the ion exchange of the polymer on the immobilized enzyme surface should be responsible for the enzyme functional changes. The modification of the biocatalysts with this polymer produced mixed results for enzyme activity (depending on the enzyme loading, use of aminated or non-aminated enzyme, polymer concentration and used substrate), in some instances more than doubling the activity, in others reducing it by 5–6 times the activity when compared to the unmodified biocatalyst. The effects on biocatalyst stability were also mixed, depending on the same factors; in some instances, great stabilization could be found (e.g., in inactivation of the highly loaded aminated biocatalyst at pH 7.0, the unmodified biocatalyst kept 5% of the initial activity, while the biocatalyst modified with 1% of the polymer maintained 80%), but in other instances, enzyme stability was reduced after modification. It was shown that one of the effects of the polymer modification was the prevention of the enzyme release during inactivation.

Edición crítica de la obra de Lope de Vega 'La carbonera', incluida en la 'Parte XXII' de sus comedias. Edición llevada a cabo siguiendo los criterios del Grupo PROLOPE (Universitat Autònoma de Barcelona).

Titin, as the main protein responsible for the passive stiffness of the sarcomere, plays a key role in diastolic function and is a determinant factor in the etiology of heart disease. Titin stiffness depends on unfolding and folding transitions of immunoglobulin-like (Ig) domains of the I-band, and recent studies have shown that oxidative modifications of cryptic cysteines belonging to these Ig domains modulate their mechanical properties in vitro. However, the relevance of this mode of titin mechanical modulation in vivo remains largely unknown. Here, we describe the high evolutionary conservation of titin mechanical cysteines and show that they are remarkably oxidized in murine cardiac tissue. Mass spectrometry analyses indicate a similar landscape of basal oxidation in murine and human myocardium. Monte Carlo simulations illustrate how disulfides and S-thiolations on these cysteines increase the dynamics of the protein at physiological forces, while enabling load- and isoform-dependent regulation of titin stiffness. Our results demonstrate the role of conserved cysteines in the modulation of titin mechanical properties in vivo and point to potential redox-based pathomechanisms in heart disease.