Repositorio Institucional UCSC (Univ. Católica de la Santísima Concepción)
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A comparative cradle-to-grave GHG assessment approach of cultivated and residual woody and herbaceous biomass utilization pathways
Get PDFThis study presents a systematic cradle-to-grave assessment of greenhouse gas (GHG) emissions from four biomass utilization pathways: combustion, pyrolysis, gasification, and anaerobic digestion. Emission factors (EF) were developed through comprehensive literature synthesis of 149 datasets from 29 peer-reviewed publications, encompassing cultivation, transport, pretreatment, conversion, and construction emissions, as well as carbon sequestration and energy offset benefits. The studies were compared using an emission factor as approximate value. Potential GHG sinks through the use of biogenic residues were calculated based on the emission factor and residue potential databases. Results indicate that previously unused biogenic residues using the utilization pathways pyrolysis have significant GHG reduction potential (from 11.0 million to 19.1 million t CO2e). Quantitative analysis reveals woody biomass residues in pyrolysis applications achieved the most favorable GHG performance (−0.87 ± 0.44 t CO2e/t feedstock), followed by combustion (−0.78 ± 0.28 t CO2e/t feedstock). Herbaceous biomass residues demonstrated similar trends with pyrolysis (−0.67 ± 0.37 t CO2e/t) outperforming combustion (−0.60 ± 0.20 t CO2e/t). From 2045, avoidable GHG emissions from urea and lime fertilization in Germany (2023: 13.7 million t CO2e) could be fully compensated on average by focusing on the technically useable potential of biogenic woody and herbaceous biomass residues
Revisiting the Default Risk-ESG Relationship: New Evidence in European Markets
No full textThis study investigates the impact of Environmental, Social, and Governance (ESG) initiatives on corporate default risk, utilizing a panel dataset of non-financial firms across 20 European countries from 2008 to 2022. While previous research has predominantly explored the relationship between ESG practices and firm value, the link between ESG dimensions and corporate risk remains underexamined. Using the Generalized Method of Moments (GMM) approach, our findings reveal a statistically significant negative relationship between ESG initiatives and default risk, particularly in industries with low environmental impact. We also uncover a novel non-linear relationship between financial transparency, a key component of governance, and default risk, where moderate levels of transparency minimize insolvency risk. The study provides new empirical insights, highlighting the importance of ESG initiatives in corporate risk management, particularly in enhancing access to capital and fostering long-term financial stability. Additionally, the research carries key policy implications for regulators, investors, and corporate managers, emphasizing the importance of robust sustainability frameworks and transparent governance practices
A skew-symmetric-based mixed FEM for stationary MHD flows in highly porous media
No full textWe propose and analyze a new mixed variational formulation for the coupling of the convective Brinkman–Forchheimer and Maxwell equations for stationary magnetohydrodynamic flows in highly porous media. Besides the velocity, magnetic field, and a Lagrange multiplier associated with the divergence-free condition of the magnetic field, our approach introduces a convenient translation of the velocity gradient and the pseudostress tensor as additional unknowns. Consequently, we obtain a five-field mixed variational formulation within a Banach space framework, where the aforementioned variables are the main unknowns of the system, exploiting the skew-symmetric property of one of the involved operators. The resulting mixed scheme is then equivalently written as a fixed-point equation, allowing the application of the well-known Banach theorem, combined with classical results on nonlinear monotone operators and a sufficiently small data assumption, to prove the unique solvability of the continuous and discrete systems. In particular, the analysis of the discrete scheme requires a quasi-uniformity assumption on the mesh. The finite element discretization involves Raviart–Thomas elements of order k>0 for the pseudostress tensor, discontinuous piecewise polynomial elements of degree k for the velocity and the velocity gradient translation, Nédélec elements of degree k for the magnetic field, and continuous piecewise polynomial elements of degree k+1 for the Lagrange multiplier. We establish stability, convergence, and optimal a priori error estimates for the corresponding Galerkin scheme. Theoretical results are illustrated by numerical tests
Concretização da política de saúde migrante internacional no currículo de ciências da saúde no Chile
Get PDFIntroducción: En Chile, la Política de Salud de Migrante Internacional establece la incorporación curricular de temáticas sobre migración, interculturalidad, derechos humanos, determinantes sociales y género en la Educación Superior; pero, se desconoce si esto ocurre de manera efectiva. Objetivo: Comprender la concreción de la Política de Salud de Migrante Internacional en el currículum de Ciencias de la Salud. Materiales y Métodos: Estudio Interpretativo/Hermenéutico que incluyó entrevistas semiestructuradas a jefes de carrera, académicos-docentes, guías clínicos y estudiantes, además de análisis documental de diferentes carreras de la salud de tres Universidades regionales de Chile. El análisis de datos incluyó codificación abierta, axial y selectiva con la asistencia del programa ATLAS.ti 24. Resultados: Participaron 179 informantes. Se conformaron tres categorías: Ámbito Institución de Salud, Ámbito Institución Universitaria y Ámbito de la Carrera, cada una con subcategorías facilitadoras u obstaculizadoras para la concreción de la política. El análisis Hermenéutico permitió interrelacionar las subcategorías para comprender el fenómeno global con una red semántica. Los facilitadores fueron escasos y aislados de la red. Los obstaculizadores están en mayor cantidad, más cohesionados y robustos, originando una formación profesional etnocéntrica que se valida con una atención de salud etnocéntrica en los campos clínicos. Discusión: Se propone el concepto de Gríngola Cultural en vez de Ceguera Cultural, porque existe consciencia de los factores culturales que influyen en la atención de salud, pero no se incorporan. Conclusiones: El currículum no responde a la Política de Salud de Migrante Internacional, es imperativo contar con políticas mancomunadas entre el Ministerio de Educación y Ministerio de Salud que reviertan el statu quo existente en la estructura sanitaria
Vertical or horizontal force-velocity profile: which one is more sensitive to detect the fatigue induced by a basketball-specific protocol?
Get PDFThis study aimed to determine which task (jumping or sprinting) and which force-velocity (F-V) relationship parameter (maximal force [F0], maximal velocity [v0], or maximal power [Pmax]) is the most sensitive indicator of fatigue induced by a basketball-specific protocol. Following a familiarization session, 19 junior male basketball players completed an experimental session in which both vertical (jumping) and horizontal (sprinting) F-V profiles were measured before, during and after undergoing a basketball-specific fatigue protocol (modified version of the Loughborough Intermittent Shuttle Test). All F-V relationship parameters, except horizontal F0 (p = .328), were significantly reduced after fatigue (p ≤ .042). The vertical Pmax (ES = -0.48 to -0.80), horizontal Pmax (ES = -0.58 to -1.28), and horizontal v0 (ES = -0.81 to -0.98) showed larger reductions compared to the pre-fatigue assessment than the vertical v0 (ES = -0.19 to -0.27), vertical F0 (ES = -0.16 to -0.25), and horizontal F0 (ES = -0.11 to -0.30). When the percentage changes with respect to the pre-fatigue assessment were compared between the jumping and sprinting tasks, no significant differences in their magnitude (p ≥ .364) and trivial to small correlations (-0.23 ≤ r ≤ 0.19) were detected. The results suggest that Pmax is the most suitable parameter to detect fatigue following a basketball-specific fatigue protocol, while the lack of significant correlations for the changes in F-V relationship parameters highlight the importance of measuring both the vertical and horizontal F-V profiles to gain comprehensive understanding of the changes in the mechanical properties of lower-body muscles following fatigue protocols
Revisão sistemática sobre aposentadoria acadêmica na América Latina
Get PDFEsta revisión sistemática de literatura tiene como objetivo explorar la producción científica en Latinoamérica relacionada a los procesos de jubilación en el contexto de la academia. Para alcanzar este objetivo, esta publicación busca identificar los objetivos de los estudios, describir las metodologías utilizadas y categorizar las trayectorias de jubilación descritas. Para esto se utilizó el modelo PRISMA con publicaciones de los últimos 10 años, junto con un enfoque de 5 puntos claves que hacen referencia a la temporalidad de estas trayectorias (Actitudes, Planificación, Decisión de jubilar, Ajuste y Evaluación). Los resultados muestran que la decisión de jubilar se ve afectada por una serie de factores que promueven este proceso y otros que lo inhiben. Por un lado, se observa con transversalidad en la literatura, que un factor principal inhibiendo la jubilación es la inestabilidad y vulnerabilidad económica. Esto principalmente sustentado en sistemas de seguridad social que no cumplen los requisitos para asegurar una buena calidad de vida en la vejez. Por otro lado, nuevos perfiles propuestos por las instituciones de educación superior suponen altos estándares y una multiplicidad de roles y funciones lo que en muchos casos escapan de las capacidades o sobre exigen a los/as académicos/as
Alianza para el Progreso y Acción Cívica de los Ejércitos chileno y venezolano en la Guerra Fría (1961-1970)
Get PDFEste artículo analiza la relación entre la Alianza para el Progreso y los programas de Acción Cívica de los Ejércitos chileno y venezolano durante la Guerra Fría, período 1961-1970. Las instituciones armadas de ambos países suramericanos llevaron a cabo distintos planes de contribución a la idea de desarrollo nacional de su época, principalmente enfocados en dos áreas: la instrucción técnica de soldados conscriptos y la construcción de diferentes obras públicas. La investigación se sustenta en la evidencia documental de fuentes primarias de Chile, Venezuela y Estados Unidos, ubicada en revistas militares, memorias oficiales y prensa. En definitiva, los documentos demuestran la participación activa de los dos ejércitos latinoamericanos en tareas específicas de entrenamiento técnico industrial y agropecuario, y también en labores de infraestructura
Dietary Intake of Polyphenols in Adults Residing in Chile: A Descriptive Cross-Sectional Study
No full textBackground
Polyphenols have been recognized for their protective role against chronic noncommunicable diseases. Despite growing international evidence, studies assessing polyphenol intake in Latin American populations remain scarce, particularly in Chile, where profound nutritional transitions have increased the consumption of ultra-processed foods and the burden of obesity and cardiovascular disease.
Objective
This study aimed to quantify dietary polyphenol intake in the Chilean adult population using a validated self-reported food frequency questionnaire.
Methods
A descriptive cross-sectional design was conducted in 521 adults aged ≥18 years, residing in different Chilean macrozones. Sociodemographic, anthropometric, and lifestyle data were collected, and polyphenol intake was estimated.
Results
The mean age of participants was 33.3 ± 10.1 years, with a predominance of women. The average daily intake of polyphenols was 1634.9 ± 1168.6 mg/d, with higher, though non-significant, consumption observed among women, rural residents, and individuals from the northern macrozone. Age-stratified analysis showed that men ≥30 years consumed significantly more polyphenols than younger men.
Conclusion
Fruits represented the main dietary source, followed by coffee and tea, while wine and cider contributed minimally
Understanding the use of physical computing in K-12 education: A systematic literature review
No full textPhysical computing is a field that involves the use of sensors, actuators, and microcontrollers to build systems that interact with the environment. This approach has been used in education, particularly to teach computer science, programming, computational thinking, and design concepts. This systematic review explores the use of physical computing in K-12 education, with a focus on what educational interventions are like, how they are assessed, their effects, and how students experience them. We included 43 scientific studies that describe the methodology and assessment process used in the intervention. We found that physical computing interventions have three types of expected educational outcomes: to learn physical computing itself, to improve other learning outcomes, or to improve attitudinal variables. The interventions use a variety of educational methods to achieve their goals; as well as a variety of instruments to measure outcomes. A common lesson structure has emerged, widely adopted across classrooms, including a short lecture followed by a hands-on phase, usually including teamwork to foster collaboration. Further comparative and long-term studies are needed to understand how physical computing interventions affect students, especially those who are underrepresented
Symplectic Reeb atlas and determination of periodic solutions in perturbed isotropic n-oscillators
No full textWe construct a symplectic atlas adapted to the flow action of an uncoupled isotropic n-oscillator, referred to as the Reeb atlas. In the context of Reeb's Theorem for Hamiltonian systems with symmetry, these variables are very useful for finding periodic orbits and determining their stability in perturbed harmonic oscillators. These variables separate orbits, meaning they are in bijective correspondence with the set of orbits. Hence, they are especially suited for determining the exact number of periodic solutions via reduction and averaging methods. Moreover, for an arbitrary polynomial perturbation, we provide lower and upper bounds for the number of periodic orbits according to the degree of the perturbation