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Insight into the role and fate of a natural tocopherol extract rich in gamma-isoform during sunflower oil degradation under several thermo-oxidative conditions: formation of 3,4-dehydro-tocopherols
No full textThis study evaluated the effect of adding a natural tocopherol extract rich in gamma-isoform (gTE) at 0.1 %, 0.5 %, and 3 % on the stability of sunflower oil when subjected to heating at frying temperatures in the absence of food (170 °C) and to accelerated storage (70 °C). For this purpose, degradation of linoleic acyl groups and formation of several oxidation products were monitored by 1H NMR and other markers like viscosity and Total Polar Compounds (TPC) were also assessed. Under frying conditions, gTE did not improve oil stability, as linoleic acyl group degradation was enhanced in a dose-dependent manner. In enriched oils, increased viscosity and TPC formation were generally observed but unexpectedly total aldehyde formation was significantly reduced. Under accelerated storage, the behavior of gTE greatly differed, initially promoting the degradation of linoleic acyl groups for a short period of time, but significantly retarding it later. Regarding the underlying mechanism involved, gTE slowed the isomerization of conjugated hydroperoxy-cis,trans-octadecadienoates to trans,trans-isomers, significantly postponing the generation of aldehydes and the progression of polymerisation. Under both thermo-oxidative conditions, the fate of natural and added tocopherols was also studied by DI-SPME-GC/MS. This technique enabled the identification of several degradation compounds, either specific or common to all isoforms. For the first time, 3,4-dehydro-tocopherols were identified among degradation products formed from tocopherol in food matrices during processing. Their formation was notably favoured under frying conditions, whereas 4,8,12,16-tetramethylheptadecan-4-olide was the major product during accelerated storage.
Este estudio evaluó el efecto de la adición de un extracto natural de tocoferoles rico en isoforma gamma (gTE) al 0,1 %, 0,5 % y 3 % sobre la estabilidad del aceite de girasol sometido a calentamiento a temperaturas de fritura en ausencia de alimentos (170 °C) y a almacenamiento acelerado (70 °C). Para ello, se supervisó la degradación de los grupos acilo linoleico y la formación de varios productos de oxidación mediante RMN de 1H y también se evaluaron otros marcadores como la viscosidad y el porcentaje de compuestos polares totales (TPC). En condiciones de fritura, gTE no mejoró la estabilidad oxidativa del aceite, ya que la degradación de los grupos acilo linoleico se incrementó de forma dosis dependiente. En los aceites enriquecidos, se observó en general un aumento de la viscosidad y de la formación de TPC, pero, de forma inesperada, la formación total de aldehídos se redujo significativamente. En condiciones de almacenamiento acelerado, el comportamiento del gTE fue muy diferente, ya que inicialmente promovió la degradación de los grupos acilo linoleico durante un breve periodo de tiempo, pero posteriormente la retrasó significativamente. En cuanto al mecanismo subyacente implicado, gTE ralentizó la isomerización de los hidroperoxi-cis,trans-octadecadienoatos conjugados a isómeros trans,trans, lo que retrasó significativamente la generación de aldehídos y la progresión de la polimerización. Bajo ambas condiciones termooxidativas, también se estudió mediante DI-SPME-GC/MS la evolución de los tocoferoles naturalmente presentes y añadidos. Esta técnica permitió identificar varios compuestos de degradación, tanto específicos como comunes a todas las isoformas. Por primera vez, se identificaron 3,4-dehidro-tocoferoles entre los productos de degradación formados a partir del tocoferol en matrices alimentarias durante el procesado. Su formación se vio favorecida notablemente en condiciones de fritura, mientras que el 4,8,12,16-tetrametilheptadecan-4-olida fue el producto principal durante el almacenamiento acelerado.This work was supported by Grant PID2021-123521OB-I00 funded by MCIU/AEI/10.13039/501100011033/ and by “ERDF A way of making Europe”, and by Grant IT1490-22 funded by the Basque Government (EJ-GV) and its Departments of Universities and Research. S. A- P thanks UPV/EHU for a predoctoral-fellowship (PIF22/35). Open cess funded by UPV/EHU
Dynamic Covalent Adaptive Cellular Solids: Recyclable Polymer Foams and Reconfigurable Lattice Metamaterials
No full text147 p.This thesis investigates the use of Covalent Adaptable Networks (CANs) to introduce adaptability and sustainability into two classes of cellular solids: polymer foams and lattice metamaterials. The first part focuses on developing recyclable, self-blown polycarbonate foams using a thiol-triggered foaming mechanism that avoids toxic isocyanates and non-sustainable blowing agents. These foams, based on a cross-linked polycarbonate matrix with pendant hydroxyl groups, exhibit thermal reprocessability and acid-degradability. Building on this platform, the second part explores the incorporation of bio-based polyols derived from various biomass feedstocks to fabricate foams with tunable morphology, hydrophilicity, and mechanical properties. Their performance is demonstrated through application as substrates for soilless agriculture. The third part presents reconfigurable lattice metamaterials based on elastomeric CANs, in which spatially controlled Joule heating enables local and global modulation of Poisson¿s ratio. Overall, this work highlights the potential of CANs to create next-generation cellular materials that are both environmentally responsible and functionally dynamic
Black carbon effects and seasonal isotope records in the Godwin-Austen snowpack and K2 high-altitude camps
No full textThis study investigates black carbon (BC) concentrations in the seasonal snowpack on the Godwin-Austen Glacier and in surface snow at K2 Camps 1 and 2 (Karakoram Range), assessing their impact on snowmelt during the 2019 ablation season. Potential BC and moisture sources were identified through back-trajectory analysis and atmospheric reanalyses. Variations in water stable isotopes (δ1⁸O and δ2H) in the snowpack were analysed to confirm its representativeness as a climatic record for the 2018–19 accumulation season. The average BC concentration in the snow pits (12 ng g−1) generated 66 mm w.e. (or 53 mm w.e. excluding the basal zone) of meltwater. Surface snow at K2 Camp 1 showed BC concentrations of 7 ng g−1, consistent with those on the snowpack surface, suggesting it may reflect local BC levels in late February 2019. In contrast, higher concentrations at K2 Camp 2 (26 ng g−1) were potentially linked to expedition activities.This research was supported by the Spanish Government through the AEI-funded MicroFAME project (Ref. PID2022- 140975NB-I00), as well as through Ref. MDM-415 2017-0714 (incl. BALELUR-Sherpa project) and Ref. CEX2021-001201-M funded by MICIN/AEI/10.13039/501100011033. This study has been also partly supported by the Arctic Challenge for Sustainability (ArCS) Project (Program Grant Number: JPMXD130000000), the Arctic Challenge for Sustainability II (ArCS II) Project (Program Grant Number: JPMXD1420318865), and the Environment Research and Technology Development Funds (JPMEERF20172003, JPMEERF20202003 and JPMEERF20232001) of the Environmental Restoration and Conservation Agency of Japan. We are indebted to Alex Txikon (https://www.alextxikon.com) and his team of mountaineers for their logistic support and willingness to collect snow samples from the K2 camps. Finally, we extend our gratitude to Deniz Bozkurt from the University of Valparaiso for his valuable contributions
Análisis econométrico de la importancia de las condiciones laborales en la felicidad
No full text[spa] Este trabajo analiza la relación entre las condiciones de empleo y la felicidad mediante un modelo econométrico basado en datos de la encuesta estadounidense General Social Survey (GSS) del año 2022. A partir del cuestionamiento de las aproximaciones tradicionales que vinculan la felicidad únicamente al nivel de ingresos, se propone una visión más amplia que incorpora variables laborales subjetivas y estructurales. El análisis revela que factores como la satisfacción laboral, la percepción de justicia salarial, la estabilidad económica, la posibilidad de conciliación con la vida familiar y la relevancia percibida del empleo tienen un impacto significativo en el bienestar subjetivo de los individuos. Los resultados refuerzan la necesidad de reflexionar sobre el papel del trabajo en la sociedad contemporánea, no solo como fuente de ingresos, sino como un elemento central en la construcción de la identidad, el sentido y la calidad de vida. Se concluye que el empleo, en condiciones dignas y significativas, puede ser una vía hacia la felicidad, aunque no debe convertirse en su única condición ni en su límite.[eng] The present paper analyzes the relationship between work conditions and happiness by using an econometric model based on data from the 2022 U.S. General Social Survey (GSS). Challenging traditional approaches that link happiness solely to income levels, it sets a broader perspective that incorporates both subjective and structural labor-related variables. The analysis reveals that factors such as job satisfaction, perceived wage fairness, economic stability, work-life balance, and the perceived meaningfulness of employment have a significant impact on individuals’ subjective well-being. The results highlight the need to consider the role of work in contemporary society, not only as a source of income, but as a central element in shaping identity and quality of life. The study concludes that employment, when carried out under decent conditions, can be a pathway to happiness, although it should not become its sole condition nor its limit
Existence and stability of periodic solutions in a nonlinear model of microbial populations in glacial environments
No full textWe study a nonlinear mathematical model describing the relation between microbial populations and nutrient availability in glacial environments. The model incorporates both nutrient and microorganism supply terms, together with an energy-dependent factor, reflecting periodic environmental influences such as melting and irradiation. We first analyze the autonomous case (i.e., time-independent energy factor and supplies) and provide sufficient conditions for the existence and stability of equilibrium points, including a critical threshold for nutrient accumulation that leads to qualitative changes in microbial dynamics. We also identify a pseudo-bifurcation phenomenon, where equilibria leave the biologically relevant domain without undergoing a classical bifurcation. In the non-autonomous case, we prove the existence of periodic solutions using topological degree theory and continuation methods. Numerical simulations confirm the theoretical results and illustrate distinct dynamical regimes depending on seasonal averages of the input parameters. In particular, we show that under certain conditions, microbial populations can persist with periodic oscillations, while nutrients either stabilize or accumulate over time. These results highlight how nutrient supply thresholds, influenced by melting-driven inputs, play a key role in controlling microbial abundance and nutrient cycling. This work provides a theoretical foundation for understanding microbial responses to seasonal environmental forcing in glacial and polar ecosystems.Open Access funding provided thanks to the CRUE-CSIC agreement with Springer Nature. This research was supported by the Mar\u00EDa de Maeztu Excellence Unit for the periods 2018\u20132022 (Ref. MDM-2017-0714) and 2023\u20132027 (Ref. CEX2021-001201-M), funded by MCIN/AEI/10.13039/501100011033. Open Access funding was provided by the University of the Basque Country (UPV/EHU)
Facilitative L1-transfer in nonnative sound production of monolingual and bilingual learners Phonological overlap and L2 experience
No full textVersion of record published 31 Oct, 2024.The L1-transfer pattern may be different between bilinguals and monolinguals as the former has multiple L1 candidates to transfer. This study compared how Mandarin monolingual learners (MDN), Shanghainese-Mandarin bilingual learners (SHM), and Japanese natives produce Japanese stops in word-reading and paragraph-reading tasks. The L2 Japanese learners varied in the years of learning (1–3 years). Shanghainese differs from Mandarin in that the word-medial voiced stops are prevoiced, which may allow facilitative transfer to Japanese voiced stops. As a result, SHM in general showed more target-like pronunciation of voiced stops than MDN. Regarding the L2 experience, third-year SHM produced more target-like word-medial voiced stops, whereas first-year SHM produced less target-like word-initial voiceless and word-medial voiced stops. These results suggest that the overlap between the target L2 and one of the learners’ L1s may lead to finer phonetic realization, but the facilitative transfer is subject to bilingual learners’ L2 experience.This research is supported by the Basque Government through the BERC 2022-2025 program and Funded by the Spanish State Research Agency through BCBL Severo Ochoa excellence accreditation CEX2020-001010/AEI. Peng Li is supported by the Juan de la Cierva program [JDC2022-048729-I] funded by MCIN, AEI and the European Union "NextGenerationEU"/PRTR". The authors sincerely thank Dr. Silke Hamann (University of Amsterdam) and Dr. Ying Zhang (Shanghai University) for their comments on an earlier draft of the manuscript, as well as Dr. Zhibin Chang and Dr. Yingbo Zhao for their assistance in recruiting participants
Tuning Ru/Ni sites in the perovskite-based precursor synthesis to make more efficient and durable dual-function materials for integrated CO2 capture and methanation
No full textA new generation of Dual Function Materials (DFMs) were obtained after the controlled reduction of 20 % La0.6Ca0.4Ni0.95Ru0.05O3/CeO2 synthesized combining citric acid-wetness impregnation methods. Different parameters such as pH of the starting solution, calcination protocol were modified in order to synthesize materials with variable nanostructure, surface chemistry and textural properties, thereby effectively tuning the material activity and stability for the integrated CO2 adsorption and in situ methanation operation. The samples were extensively characterized before and after catalytic tests by XRD, Raman, STEM-EDS, XPS, N2 adsorption-desorption, H2-TPR, H2-TPD, CO2-TPD, and H2-TPSR. It was found that the DFM obtained from the precursor prepared in absence of NH3 promoted Ru accommodation within the perovskite structure. The corresponding DFM showed enhanced textural properties, Ru/Ni actives sites accessibility and weak/medium basic sites concentration and, consequently, displayed the highest CH4 yield (312 µmol g−1) and fastest CH4 production kinetics under cycles of CO2 adsorption and in situ hydrogenation to CH4. Furthermore, this sample showed higher stability than conventional Ru-based DFMs, with CH4 production decreasing by less than 6 % compared to 25 % observed for conventional ones, due to a lower tendency for metal sintering, emerging as a promising alternative for long-term operation under realistic industrial conditions.This work was supported by research project PDC2022-133839-C21 and PID2022-139552OB-C21 funded by MCIN/AEI/10.13039/501100011033 and the Basque Government (Project IT1509-2022). One of the authors (JAOC) acknowledges the Post-doctoral research grant (DOCREC20/49) provided by the University of the Basque Country (UPV/EHU). The authors also thank for technical and human support provided by SGIker (UPV/EHU Advanced Research Facilities/ERDF, EU)
Flexibilidad en la pensión de jubilación del Régimen General: análisis de la compatibilidad entre la prestación económica y el trabajo remunerado
No full textLa pensión de jubilación en su modalidad contributiva es un pilar clave del Estado del Bienestar en España, garantizando la protección económica tras la vida laboral activa. Sin embargo, enfrenta retos estructurales derivados del envejecimiento poblacional, la baja natalidad y el aumento de la esperanza de vida, que ponen en riesgo su sostenibilidad financiera. Este trabajo analiza, desde una perspectiva jurídica, la viabilidad de un modelo flexible de jubilación que permita compatibilizar el trabajo con la percepción de la pensión. Se estudia la evolución normativa del régimen general de la Seguridad Social y las modalidades existentes que posibilitan esta compatibilidad, como la jubilación activa, la jubilación flexible y la jubilación parcial. Mediante un análisis crítico, se identifican las limitaciones del marco actual y se proponen reformas para flexibilizar el sistema, promover la prolongación voluntaria de la vida laboral y garantizar la sostenibilidad intergeneracional. La propuesta busca adaptar el sistema a los cambios demográficos y socioeconómicos, preservando los derechos de los trabajadores y asegurando la viabilidad financiera del sistema público de pensiones
Documentation of electronic arbitration award: a study in light of uncitral model rules and egyptian legislation
No full textThis study aims to examine the legal challenges related to the authentication of electronic arbitration awards. The study explores how these awards comply with the UNCITRAL Model Rules and Egyptian laws related to electronic transactions. This authentication aims to confirm the legal principles that establish equality between electronic and traditional formats. Therefore, electronic documents and signatures are granted equivalent evidentiary authority to paper documents and traditional signatures. Finally, it is recommended to establish an international legal framework to promote the authentication of electronic arbitration awards, ensure mutual recognition by national and international courts, and enhance transparency and security in electronic arbitration platforms
Development of Conjugated Microporous Polymers as High-Performance Organic Electrodes for Next-Generation Aqueous and Non-Aqueous Batteries
No full text309 p.This thesis investigates the development and optimization of advanced aqueous and non-aqueous (semi)organic batteries, focusing on Conjugated Microporous Polymer (CMP) electrodes. The research aims to enhance the electrochemical performance, practicability, and sustainability of organic batteries while addressing key challenges such as poor processability, slow kinetics, high solubility, and low practicability issues of organic electrodes. With the broader goal of advancing organic batteries, this thesis is structured into several chapters, each addressing distinct yet interconnected aspects of the research. The structure includes: Chapter 1: Overview of the research background and challenges in CMP-based battery systems.Chapter 2: Objectives of the thesis.Chapter 3: Methods for CMP synthesis, characterization, and battery testing.Chapters 4¿8: Key findings, including: Chapter 4: Development of anthraquinone-based CMP anodes for alkaline batteries, achieving high energy density and improved practicality.Chapter 5: Phenazine-based CMP (IEP-27-SR) showing high hydronium-ion storage in acidic media.Chapter 6: IEP-27-SR paired with MnO¿ cathodes for high-performance acid batteries.Chapter 7: IEP-27-SR's application in lithium-ion batteries with optimized electrolytes.Chapter 8: IEP-27-SR as a cathode for aluminum metal batteries with exceptional durability.Chapter 9: Conclusions and future challenges.This research advances CMP-based battery technologies with significant performance improvements across various system