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Genetic diversity and structure of the commercially important sea cucumber Athyonidium chilensis along the coast of Chile
No full textAthyonidium chilensis is a sea cucumber species that inhabits both the intertidal and subtidal zones of the southeast coast of the Pacific Ocean. This species is considered a commercially valuable fishery resource in Peru and Chile, which is exported to Asian countries for human consumption as a dried product. Despite its commercial importance, the spatial distribution of the genetic variability in A. chilensis along its geographic range remains unstudied. This information is crucial to define population stocks and to establish science-based management and conservation plans. Hence, our study aimed to assess the genetic structure and diversity of A. chilensis using DNA from adult specimens from six natural banks located between 18 °S and 42 °S. We analyzed 364 sequences from two genes (241 COI sequences and 123 ATPS-b sequences), which not only revealed high genetic diversity among A. chilensis populations from Chile but potentially also the presence of a second, cryptic species. Additionally, significant genetic distances were found among locations, with genetic flow decreasing with increasing spatial distance, suggesting different population stocks along the southeast coast of the Pacific Ocean. We provide crucial, baseline information to move forward with management plans for the preservation of genetic diversity for the species and the fishery to persist
Three-dimensional non-relativistic Hietarinta supergravity
Full text linkIn this work we present the non-relativistic regime of the Hietarinta gravity theory and its extension to supergravity. At the bosonic level, we derive the non-relativistic version of the Hietarinta model by employing a contraction process and addressing the non-degeneracy of the invariant metric. To incorporate supersymmetry, we apply the Lie algebra expansion method to obtain the non-relativistic formulation of N=2 Hietarinta supergravity. Our results reveal that the non-relativistic Hietarinta theory encompasses the extended Bargmann (super)gravity as a special case, yet it differs significantly from other existing non-relativistic (super)gravity models. Furthermore, we generalize our analysis to include a cosmological constant term in the non-relativistic Hietarinta (super)gravity action and examine its effects on the torsion structure
Recent Advances in TiO2-Based Photocatalysts for Efficient Water Splitting to Hydrogen
Full text linkTitanium dioxide (TiO2) has been widely used as a potential candidate for the production of green hydrogen using the artificial photosynthesis approach. However, the wide bandgap (∼3.3 eV) of anatase TiO2 makes it difficult to absorb a large fraction of the solar radiation reaching the Earth, thus providing a low photocatalytic activity. Anatase TiO2 absorbs only 4% of solar radiation, which can be improved by engineering its bandgap to enhance absorption in the visible region. In the literature, many strategies have been adopted to improve the photocatalytic activity of TiO2, such as metal and non-metal doping and heterojunctions. These techniques have shown incredible enhancement in visible light absorption and improved photocatalytic activity due to their ability to lower the bandgap of pure TiO2 semiconductors. This review highlights different techniques like doping, heterojunctions, acidic modification, creating oxygen vacancies, and temperature- and pressure-dependence, which have improved the photochemical response of TiO2 by improving charge-transfer efficiencies. Additionally, the charge-transfer mechanism and enhancement in the photochemical response of TiO2 is discussed in each portion separately
Alliance for Progress and The Inter-American Defense System (1961-1969)
Full text linkEste trabajo analiza las respuestas que tuvo el Sistema Interamericano de Defensa (SID) en el contexto de la Alianza para el Progreso durante la Guerra Fría global en los años sesenta. Metodológicamente, se consideran hitos históricos del continente americano con influencia y repercusión en la seguridad regional, los que fueron examinados a partir de documentación original primaria proveniente de archivos estadounidenses: The American Presidency Project, Eisenhower Library, Kennedy Library, y el Archivo OEA, que fueron interpretadas dentro de su tiempo-espacio. En particular, se estudian tres casos diferentes: la Crisis de los Misiles en Cuba de 1962, la Crisis Dominicana de 1965, y la consecución del Tratado de Tlatelolco de 1967. En suma, se propone una interpretación histórica del conjunto de estas experiencias en las que estuvo a prueba la capacidad de reacción de la seguridad hemisférica, la relaciones entre los Estados americanos, y también las posiciones críticas en los momentos de desacuerdo
Towards an epistemological model of media competence: paideia, maieutics and classical thought
Full text linkLa competencia mediática ha cobrado relevancia en el siglo XXI como una habilidad esencial para enfrentar los retos del entorno mediático. Este ensayo explora sus objetivos y busca un sustento epistemológico que facilite su comprensión. Se propone una relación entre la competencia mediática, la paideia griega y la mayéutica, cuestionando el paradigma positivista que ha predominado en el estudio de los medios. Finalmente, se integran elementos de escuelas clásicas del pensamiento para enriquecer su enfoque y ofrecer un fundamento epistemológico que refuerce su propósito de bien social e individual
River Resilience: Assessment Using Empirical Fish Assemblage Traits
Full text linkThe Andean river basins of central–southern Chile face multiple anthropogenic disturbances, including water extraction, hydropower, mining, and industrial discharges, which affect their ability to adapt to new disturbances. Disturbance intensity forms a gradient from high (Maipo, Rapel, Biobío, Maule) through medium (Mataquito, Itata) to low (Imperial, Toltén). This study evaluated resilience in these eight river basins based on fish assemblages, using taxonomic and functional trait indices within the framework of the three Rs of resilience: resources, recruitment, and refugia. Taxonomic indices captured changes in species richness, abundance, diversity, evenness, and beta diversity, while functional traits reflected the fish species characteristics promoting resilience. Statistical tests revealed significant differences in resilience indices among basins. Recruitment was the most impacted resilience mechanism, with beta diversity revealing effects from river fragmentation in the Maipo, Rapel, and Biobío basins. The resources mechanism was also affected, primarily by land-use changes and water pollution, leading to low species richness in the Maipo, Rapel, Mataquito, and Maule river basins. Interestingly, basins with medium disturbance levels showed high resilience, indicating adaptive responses to moderate impacts. This study emphasizes the importance of multiple indicators to assess ecosystem resilience and calls for integrated strategies to address the complex challenges impacting freshwater biodiversity
Imaginários sociais baseados nos conceitos de inclusão e integração presentes no trabalho dos professores e da equipe PIE, de uma comunidade educativa da comuna de Concepción, Chile.
No full textLa inclusión escolar ha sido ampliamente promovida tanto en la normativa como en la práctica pedagógica en los últimos años. No obstante, surge la interrogante de si estas prácticas son verdaderamente inclusivas o si, por el contrario, permanecen dentro de un paradigma predominantemente integrativo. Este artículo aborda esta problemática desde la teoría de los imaginarios sociales, con el propósito de identificar los imaginarios sociales dominantes y emergentes relacionados con los conceptos de inclusión e integración en la labor docente y en el equipo del Programa de Integración Escolar (PIE) de una comunidad educativa en Concepción, Chile. Para ello, se plantearon dos objetivos específicos: (i) analizar los discursos de los(as) entrevistados(as) y (ii) identificar los imaginarios sociales asociados a la inclusión e integración en las prácticas pedagógicas del equipo PIE, a partir de los testimonios recopilados. El estudio se desarrolló bajo un enfoque cualitativo interpretativo con un marco fenomenológico, empleando la técnica de análisis de contenido. Los resultados evidenciaron el predominio de imaginarios sociales ligados al concepto de integración, influenciados por las normativas que regulan los PIE. Sin embargo, también emergió un imaginario alternativo orientado hacia la inclusión escolar, lo que revela una tensión entre ambos paradigmas dentro del contexto educativo analizado
Starch and polyacrylic acid doped tin ferrite nanocubes for catalytic, water oxidation, and antimicrobial activities inhibiting DNA gyrase with molecular docking
No full textThe textile sector poses global pollution through the discharge of organic dyes and antibiotic-resistant pathogens present in the environment have a significant impact on the quality of water resources. The present work demonstrates different concentrations (2 and 4 wt%) of starch (St) and a fixed amount of polyacrylic acid (PAA) doped tin ferrite (SnFe2O4) nanocubes (NCs) prepared by co-precipitation route. The proposed approach has the potential to degrade rhodamine B (RhB) dye, oxygen evolution reaction (OER) activity, and resist the growth of Gram-negative multiple drug resistant (MDR) Escherichia coli (E. coli), contributing to environmental remediation. XRD showed the multiple phases of SnFe2O4 and crystallite size significantly increased from 35.79 to 42.09 nm, with the addition of dopants. TEM images revealed the cube-like structural morphology of SnFe2O4 and doped samples exhibited the agglomerated NCs. The catalytic performance of 4 % St/PAA-SnFe2O4 NCs towards Rhodamine B (RhB) was 73.33 % in a neutral medium. The better OER performance of 4 % St/PAA-SnFe2O4 is attributed to lower overpotential, Tafel slope, and charge transfer resistance. Moreover, the highly doped sample highlighted strong bactericidal effectiveness for resistant Escherichia coli (E. coli) by showing a 6.45 ± 0.02 mm inhibition zone
Effects of biotic interactions on ecological niche dynamics: Low niche equivalence among amphidromous fish life‐history strategies
No full text1) Although key biotic interactions can shape species distributions across large geographic areas, the specific roles and spatial scales of these interactions are not well understood. Correlational models, often used in ecological studies, assume niche equivalence among populations of a species. However, this assumption overlooks how different factors can affect defined ranges and the reliability of predictions.
2) In this study, we evaluate ecological niche equivalence among populations of the facultative amphidromous fish Galaxias maculatus, which includes both migratory amphidromous and freshwater resident populations. We identify sources of niche variation across hierarchical levels of biological organization (individuals, populations, species) and operational niche definitions (existing fundamental niche, realized niche).
3) Our findings reveal structural niche differences based on population movement ranges and the operational niche definition used. Notably, no overlap exists in realized niches between amphidromous and freshwater resident populations, with isotopic niche breadth driving this differentiation. This niche difference resulted in models that poorly predicted distributions of populations with different life-history strategies, indicating low niche equivalence between these groups when considering biotic factors.
4) Our results suggest that differing life-history strategies are key drivers of G. maculatus distribution. Habitat selectivity based on freshwater recruitment conditions and loss of diadromy through local adaptation may also contribute to niche divergence. We emphasize the importance of assessing niche breadth changes across hierarchical levels to understand species' distributional patterns better, particularly in species with complex life-history strategies
Suicide Attempt in Elderly Individuals in a Tertiary Health Center: 13-Year Follow-up
Full text linkEl suicidio es una importante causa de muerte en personas de 60 y más años. Los intentos de suicidio (IS) son un poderoso factor de riesgo.
Objetivo: Describir y evaluar la relación de características sociodemográficas y clínicas con IS en personas mayores hospitalizadas en Unidad de Psiquiatría del Hospital Herminda Martin de Chillán, Chile, y efectuar un seguimiento de dicha conducta durante 13 años.
Métodos: Estudio correlacional con datos de base estadística y seguimiento de serie de casos durante 13 años. Participaron 49 personas mayores con IS y 194 sin IS que estuvieron en hospitalización psiquiátrica entre el 01/01/2011 y 31/12/2023. Se efectuó seguimiento hasta octubre de 2024. Se estudiaron variables sociodemográficas y clínicas. Se realizó análisis descriptivo y bivariado.
Resultados: El IS se relacionó significativamente con grupo etario de mayor edad (mayores de 70 años), sexo masculino y presencia de factores estresantes en el grupo primario de apoyo y problemas de vivienda. Los métodos suicidas más empleados fueron la ingesta de medicamentos y la asfixia por ahorcamiento. La conducta suicida se relacionó significativamente con diagnóstico psiquiátrico especialmente con trastorno depresivo, pero no con enfermedad médica comórbida. Un porcentaje considerable tenía IS previos y reiteró la conducta post alta. Los factores precipitantes y razones para morir más aludidos fueron los conflictos familiares y sentimientos adversos. En el seguimiento se constató 1 suicidio, 2 muertes por complicaciones de un nuevo IS y 1 muerte por condiciones médicas durante su hospitalización por IS.
Conclusiones: Las características de los IS de personas mayores se asemejan a las del suicidio. En este grupo etario se requiere focalizar la prevención no sólo en la pesquisa y tratamiento de la depresión, sino que también en conducta suicida previa, factores psicosociales adversos y en la continuidad de los cuidados con intervenciones de seguimiento