Institutional Repository Universidad San Sebastián
Not a member yet
9206 research outputs found
Sort by
First principles study for Ag-based core-shell nanoclusters with 3d-5d transition metal cores for the oxygen reduction reaction
No full textFamilia-participación: un análisis de la política educativa en el currículum de educación parvularia en Chile
No full textLa investigación educativa nos manifiesta que la familia es fundamental en los procesos de enseñanza aprendizaje, y que su intervención en conjunto con la comunidad educativa puede contribuir en el desarrollo de niños y niñas, desde esta perspectiva resulta fundamental conocer la política educativa en educación inicial y analizar lo que esta manifiesta de la familia y su relación con la educación parvularia. El objetivo del estudio es conocer el estado de la situación de la política educativa en el currculum educación parvularia vinculada a la familia, ante este supuesto emerge un estudio de características descriptiva con un método de análisis documental desde los principales documentos que rigen el estado de la situación de la educación parvularia en Chile. Los resultados manifiestan que los documentos de política educativa analizados se ajustan de manera parcial al enfoque curricular praxeológico del currículo de educación parvularia, su principal debilidad es el escaso sustento teórico que permita construir una fundamentación solida de la importancia de la familia y participación como constructos de inclusión educativa. Como conclusión se declara que es necesario una política educativa para el trabajo de la familia y la educación inicial desde una perspectiva sociocrítica dejando de lado la mirada funcional, dichapolítica debe estar centrada en la participación como una mayor colaboración entre todos los actores involucrados en la educación de los niños y niñas, lo que a su vez contribuiría a mejorar la calidad de la enseñanza y el aprendizaje en esta etapa crucial del desarrollo infantil
Trapping Charge Mechanism in Hv1 Channels (CiHv1)
No full textPublisher Copyright: © 2023 by the authors.The majority of voltage-gated ion channels contain a defined voltage-sensing domain and a pore domain composed of highly conserved amino acid residues that confer electrical excitability via electromechanical coupling. In this sense, the voltage-gated proton channel (Hv1) is a unique protein in that voltage-sensing, proton permeation and pH-dependent modulation involve the same structural region. In fact, these processes synergistically work in concert, and it is difficult to separate them. To investigate the process of Hv1 voltage sensor trapping, we follow voltage-sensor movements directly by leveraging mutations that enable the measurement of Hv1 channel gating currents. We uncover that the process of voltage sensor displacement is due to two driving forces. The first reveals that mutations in the selectivity filter (D160) located in the S1 transmembrane interact with the voltage sensor. More hydrophobic amino acids increase the energy barrier for voltage sensor activation. On the other hand, the effect of positive charges near position 264 promotes the formation of salt bridges between the arginines of the voltage sensor domain, achieving a stable conformation over time. Our results suggest that the activation of the Hv1 voltage sensor is governed by electrostatic–hydrophobic interactions, and S4 arginines, N264 and selectivity filter (D160) are essential in the Ciona-Hv1 to understand the trapping of the voltage sensor
Massless Rarita-Schwinger equations : Half and three halves spin solution
No full textPublisher Copyright: © 2024 SciPost Foundation. All rights reserved.Counting the degrees of freedom of the massless Rarita-Schwinger theory is revisited using Behrends-Fronsdal projectors. The identification of the gauge invariant part of the vector-spinor is thus straightforward, consisting of spins 12 and 23 . The validity of this statement is supported by the explicit solution found in the standard gamma-traceless gauge. Since the obtained systems are deterministic –free of arbitrary functions of time–we argue that the often-invoked residual gauge symmetry lacks fundamental grounding and should not be used to enforce new external constraints. The result is verified by the total Hamiltonian dynamics. We conclude that eliminating the spin- 21 mode via the extended Hamiltonian dynamics would be acceptable if the Dirac conjecture was assumed; however, this framework does not accurately describe the original Lagrangian system
Estudio por titulación potenciométrica del control de incrustaciones de CaCO3 con peliculas insolubles en agua de polieterimida y polieterimida sulfonada
No full textPublisher Copyright: © 2024Automatic potentiometric titration (APT) is a chemical analysis method to study the crystallization of CaCO 3 in solution. We demonstrate how APT is also valuable for studying CaCO 3 crystallization using water-insoluble polymer films, ideal for studying surfaces exposed to Ca 2+ and CO 3 2− ions with the capacity to remove Ca 2+ and/or susceptible to scale formation, equipment surfaces, ion exchange surfaces or desalination membranes, etc. Polyetherimide (PEI) and sulfonated polyetherimide (SPEI) films were prepared by solvent casting technique, and their surface studied using FESEM, XPS, Z potential, and contact angle. APT assays were performed with polymer films, using a carbonate buffer (pH 9), dosed with CaCl 2, and monitoring free Ca 2+. The APT curves with PEI showed no significant difference compared to the control, while the presence of SPEI film affected the kinetics of CaCO 3 formation. This was evidenced by changes in the slope and peak maximum of the APT curves. FTIR, XRD, and FESEM of the polymeric films and the CaCO 3 after the APT assays showed control over the types of CaCO 3 polymorphs. We show that the SPEI film is a good candidate to delay the formation of CaCO 3 in water, through the adsorption of Ca 2+ ions and the adsorption of pre-nucleation clusters of CaCO 3
Condition Monitoring Using Digital Fault-Detection Approach for Pitch System in Wind Turbines
No full textPublisher Copyright: © 2024 by the authors.The monitoring of wind turbine (WT) systems allows operators to maximize their performance, consequently minimizing untimely shutdowns and related hazard situations while maximizing their efficiency. Indeed, the rational monitoring of WT ensures the identification of the main sources of risks at a proper time, such as internal or external failures, hence leading to an increase in their prevention by limiting the faults’ occurrence regarding the different components of wind turbines, achieving production objectives. In this context, the present paper develops a practical monitoring approach using a numerical fault-detection process for the pitch system based on a benchmark wind turbine (WT) model with the main aim of improving safety and security performance. Therefore, the proposed fault-diagnosis procedure deals with eventual faults occurring in the actuators and sensors of the pitch system. In this proposed approach, a simple, logical process is used to generate the correct residuals as fault information based on the redundancy in the actuators and sensors of the pitch sub-systems. The obtained results demonstrate the effectiveness of this proposed process for ensuring the tasks of the fault diagnosis and condition monitoring of the WT systems, and it can be a promising approach for avoiding major damage in such systems, leading to their operational stability and improved reliability and availability
Interplay between the brain and adipose tissue a metabolic conversation
No full textPublisher Copyright: © The Author(s) 2024.The central nervous system and adipose tissue interact through complex communication. This bidirectional signaling regulates metabolic functions. The hypothalamus, a key homeostatic brain region, integrates exteroceptive and interoceptive signals to control appetite, energy expenditure, glucose, and lipid metabolism. This regulation is partly achieved via the nervous modulation of white (WAT) and brown (BAT) adipose tissue. In this review, we highlight the roles of sympathetic and parasympathetic innervation in regulating WAT and BAT activities, such as lipolysis and thermogenesis. Adipose tissue, in turn, plays a dual role as an energy reservoir and an endocrine organ, secreting hormones that influence brain function and metabolic health. In addition, this review focuses on recently uncovered communication pathways, including extracellular vesicles and neuro-mesenchymal units, which add new layers of regulation and complexity to the brain–adipose tissue interaction. Finally, we also examine the consequences of disrupted communication between the brain and adipose tissue in metabolic disorders like obesity and type-2 diabetes, emphasizing the potential for new therapeutic strategies targeting these pathways to improve metabolic health
Exact partition function of the Potts model on the Sierpinski gasket and the Hanoi lattice
No full textPublisher Copyright: © 2024 IOP Publishing Ltd and SISSA Medialab srl.We present an analytic study of the Potts model partition function on the Sierpinski and Hanoi lattices, which are self-similar lattices of triangular shape with non integer Hausdorff dimension. Both lattices are examples of non-trivial thermodynamics in less than two dimensions, where mean field theory does not apply. We used and explain a method based on ideas of graph theory and renormalization group theory to derive exact equations for appropriate variables that are similar to the restricted partition functions. We benchmark our method with Metropolis Monte Carlo simulations. The analysis of fixed points reveals information of location of the Fisher zeros and we provide a conjecture about the location of zeros in terms of the boundary of the basins of attraction
Groove of the Iliopsoas Muscle and its Clinical Relationship with the Hip. A Review
No full textPublisher Copyright: © 2024, Universidad de la Frontera. All rights reserved.The iliopsoas muscle is the main hip flexor being an accessory lateral rotator of this, its fibers run posterior to the inguinal ligament, crossing anterior to the pelvis. This course occurs in a groove located between the iliopubic eminence medially and the anterior inferior iliac spine laterally. Although there are antecedents of this groove, no relevant comments are found in international anatomical terminology (IAT) as a groove within the pelvic bone reliefs. This groove is associated with the tendon in different hip dysfunctions, such as the hip snap (coxa saltans). The objective of the research is to expand the clinical and anatomical knowledge of this groove and its inclusion in international anatomical terminology. Within the inclusion criteria, articles published in Spanish and English were selected that referred to the groove and/or keywords such as "iliopsoas muscle", "iliopsoas muscle", "iliopsoas groove", "coxal groove", "iliopsoas groove". and “iliopsoas muscle” “coxal groove”. The search engines used were Pubmed, Google Scholar and Springer Link. The relevance of the iliopsoas muscle groove gives way to discussions regarding its shape and depth, as well as a point of reference associated with different clinical situations related to this groove and probable predispositions to injuries or snaps that occur in the hip. Finally, knowledge of the groove for the iliopsoas muscle is important to consider in research that addresses this region, as well as its anatomical terminology, anatomical, clinical, and surgical relationships.The iliopsoas muscle is the main hip flexor being an accessory lateral rotator of this, its fibers run posterior to the inguinal ligament, crossing anterior to the pelvis. This course occurs in a groove located between the iliopubic eminence medially and the anterior inferior iliac spine laterally. Although there are antecedents of this groove, no relevant comments are found in international anatomical terminology (IAT) as a groove within the pelvic bone reliefs. This groove is associated with the tendon in different hip dysfunctions, such as the hip snap (coxa saltans). The objective of the research is to expand the clinical and anatomical knowledge of this groove and its inclusion in international anatomical terminology. Within the inclusion criteria, articles published in Spanish and English were selected that referred to the groove and/or keywords such as "iliopsoas muscle", "iliopsoas muscle", "iliopsoas groove", "coxal groove", "iliopsoas groove". and “iliopsoas muscle” “coxal groove”. The search engines used were Pubmed, Google Scholar and Springer Link. The relevance of the iliopsoas muscle groove gives way to discussions regarding its shape and depth, as well as a point of reference associated with different clinical situations related to this groove and probable predispositions to injuries or snaps that occur in the hip. Finally, knowledge of the groove for the iliopsoas muscle is important to consider in research that addresses this region, as well as its anatomical terminology, anatomical, clinical, and surgical relationships
Taninos condensados de corteza de Pinus radiata: Extracción y preparación de nanopartículas en agua utilizando métodos verdes
No full textPublisher Copyright: © 2024 Elsevier B.V.This work reports for the first time the production of condensed tannin nanoparticles stable in water via modification with glycine betaine. Pine bark, as a byproduct from the paper industry, was used as a source of condensed tannins of high molecular weight. Different glycine betaine concentrations were tested to produce condensed tannin nanoparticles, and the obtained nanoparticles were subjected to several characterization techniques (Dynamic Light Scattering, Field emission scanning electron microscopy, Zeta potential, Fourier transform infrared spectroscopy-Attenuated total reflectance, thermogravimetric analysis). The results showed that the highest stability possessed nanoparticles with 40 wt% glycine betaine. The average particle size distribution evaluated by scanning microscopy was 124 nm. Besides, the glycine betaine-modified condensed tannin nanoparticles demonstrated higher thermal stability with the starting degradation temperature at 238 °C. Finally, obtained nanoparticles showed an antioxidant capacity of 34,209 ± 2194 μmol ET/100 g and low cytotoxicity towards healthy human cells, representing the high potential to be used as a carrier of active compounds in agriculture, food, drug and medical sector