University of Bío-Bío

Genomic adaptation and introgression can occur during the speciation process, enabling species to diverge in their frequencies of adaptive alleles or acquire new alleles that may promote adaptation to environmental changes. There is limited information on introgression in organisms from extreme environments and their responses to climate change. To address these questions, we focused on the three southern skua species, selected for their widespread distribution across the Southern Hemisphere and their complex history of speciation and introgression events. Our genomic data reveal that these skuas underwent diversification around the Penultimate Glacial Period, followed by subsequent demographic expansion. We identified a geographic region of introgression among species that followed a directional pattern sourced from the Antarctic continent, South America, and east to west in subantarctic islands, all converging towards the Antarctic Peninsula. The three skua species and admixed individuals exhibited a unique pattern of putative genes under selection, allowing adaptation to extreme conditions. Individuals with a higher proportion of brown skua ancestry showed signs of selection on genes related to reproductive isolation, while admixed individuals with a higher proportion of South Polar Skua ancestry displayed patterns resembling those of the South Polar Skua. Introgression may be a key mechanism of adaptation for many species that may help buffer against the ongoing climate change.

As ectotherms, high-elevation reptiles rely heavily on temperature fluctuations in their surroundings to maintain their physiological functions. If the rate of local adaptation does not keep up with the rise in temperature, these species are predicted to be especially vulnerable to global warming. A high-elevation endemic species from central Chile’s Mediterranean Andes, Phymaturus vociferator , lives in incredibly variable daily and seasonal thermal environments. We estimated standard thermal parameters related to body heating and developed correlational thermal models at two acclimation temperatures (20°C and 30°C) to determine their physiological vulnerability to climate change. Our results demonstrate that this species is a thermo-conformer, attributable to its ability to tolerate higher temperature regimes in the field as opposed to in the laboratory. As expected, the individuals demonstrated a higher threshold for temperature tolerance when acclimated to 20°C than when acclimated to 30°C. Additionally, we discovered that P. vociferator exhibits the widest eurythermal range among species in its genus. Although this result could help explain its potential physiological, this species’ capacity to adapt to global warming may be diminished by thermal physiological constraints.

Enzymatic hydride transfer reactions play a crucial role in numerous metabolic pathways, yet their accurate computational modeling remains challenging due to the trade-off between accuracy and computational efficiency. Ideally, molecular dynamics simulations should sample all enzyme configurations along the reaction path using post Hartree-Fock or DFT QM/MM electrostatic embedding methods, but these are computationally expensive. Here, we introduce a simple approach to improve the third-order density functional tight binding (DFTB3) semi-empirical method to model hydride transfer reactions in enzymes. We identified deficiencies in DFTB3's description of the potential energy surface for the hydride transfer step in Crotonyl-CoA Carboxylase/Reductase (Ccr) and developed a systematic methodology to address these limitations. Our approach involves modifying DFTB3's repulsive potential functions using linear combinations of harmonic functions, guided by analysis of C-H and C-C distance distributions along the reaction path. The optimized DFTB3 Hamiltonian significantly improved the description of the hydride transfer reaction in Ccr, reproducing the reference DFT activation barrier within 0.1 kcal/mol. We also addressed the transferability of our method by applying it to another hydride transfer reaction bearing the 1,4-dihydropyridine motif but exhibiting distinct structural features of the reactant, as well as the hydride transfer reaction in Dihydrofolate Reductase (DHFR). In both cases our adapted DFTB3 Hamiltonian correctly reproduced the DFT reference and experimentally observed activation barriers. The low computational cost and transferability of our method will enable more accurate and efficient QM/MM molecular dynamics simulations of hydride transfer reactions, potentially accelerating research in enzyme engineering and drug design.

This study reports the first record of the genus Aplanochytrium on the coast of Chile, belonging to the class Labyrinthulomycetes in the kingdom Stramenopila. These marine protists play an essential role in carbon and nitrogen cycles as decomposers in the aquatic ecosystem. Although ecologically significant, their global diversity and distribution must be better understood. Samples were collected from Corral Bay, Valdivia, Chile, and later cultivated and identified through classical taxonomy and molecular analysis. Phylogenetic analysis based on the 18S rRNA sequence showed that Chilean samples were recovered in the Aplanochytrium s.s . lineage. Besides Aplanochytrium kerguelense Bahnweg & Sparrow, 1972, found in Kerguelen, an antarctic island from the Indian Ocean, this report extends the geographic distribution of the genus from Asia and the Northern Hemisphere to South America. This finding enhances our understanding of the diversity and distribution of Labyrinthulomycetes. Additionally, the fatty acid profile of Aplanochytrium revealed a high proportion of docosahexaenoic acid (DHA), accounting for 50% of the total fatty acids, along with the presence of palmitic acid. Astaxanthin, a valuable pigment for biotechnological applications, was also quantified. These results highlight the importance of Labyrinthulomycetes in marine ecosystems and their potential in biotechnology.

This study aimed to investigate the chemical composition, and anticholinesterase and anti-tyrosinase activities of the essential oil extracted from the leaves of Piper frustratum Boerl., growing in Malaysia. Nineteen chemical components were identified using gas chromatography-flame ionization detection (GC-FID) and gas chromatography-mass spectrometry (GC-MS), accounting for 99.6 % of the essential oil. The identified major components include β-caryophyllene (12.6 %), β-asarone (10.7 %), myristicin (10.4 %), α-copaene (9.6 %), methyl eugenol (7.2 %), and β-cubebene (6.5 %). Anticholinesterase activity was assessed using the Ellman’s method, while anti-tyrosinase activity was evaluated against mushroom tyrosinase. The essential oil demonstrated moderate inhibitory activity against acetylcholinesterase (IC 50 value of 84.2 μg/mL), butyrylcholinesterase (IC 50 value of 98.5 μg/mL), and tyrosinase (IC 50 value of 95.4 μg/mL) enzymes. This study is the first to report the chemical composition and bioactivities of the essential oil obtained from P. frustratum , which may have implications on the characterization, pharmaceutical, and therapeutic applications of Piper essential oils.

The study reports a literature review focused on the initial training of science teachers and its relationship with science for citizenship to support a new subject in secondary school, Chile. The qualitative study included: 1. information search in the Web of Science, Scopus, and Scientific Electronic Online databases according to the proposed objectives; 2. analysis of the documentation, selection of 21 articles analyzed descriptively and comprehensively by the Preferred Reporting Items for Systematic Reviews and Meta-Analyses 2020. The results show a predominance of qualitative studies from European countries. It concludes there is a diversity of conceptualizations of "science for citizenship" and the need for an educational transformation in teacher training towards a model focused on citizenship committed to critical and environmentally responsible scientific literacy, incorporating an integrated approach to science and interdisciplinary (science and tecnhology—STS; science, technology, engineering and mathematics—STEM), with strategies based on problem-solving, socio-scientific issues—SSI, nature of science—NOS, and evaluations consistent with these changes. Keywords: Science for Citizenship; Initial Training of Science Teacher; Scientific Literacy; Interdisciplinarity; Social Justice

The pudu deer Pudu puda is a near-threatened mammal endemic to southern Chile and Argentina. Since this species inhabits mostly human-modified landscapes, addressing the factors that influence habitat use in such environments could aid in their conservation. We evaluated the presence of pudu deer during the spring-summer of 2020–2021 and 2021–2022 at two coastal range sites in the province of Osorno (Huellelhue Community, HC, and Los Riscos, RI) using camera traps. We applied logistic regression (LR) analysis to identify the predictor variables related to vegetation type, human perturbation, and native forest fragmentation that are correlated with the presence or absence of pudu deer as a binary response variable. In HC site, LR analysis identified the most likely top models including the fragmentation variable of the contiguity of patches (AICc = 22.73, Δi = 0.00 and wi = 0.77) with a negative effect (β = -8.573, P < 0.05). In RI locality the top model included the human perturbation variable of the distance to village (AICc = 23.37, Δi = 0.00 and wi = 0.71) with a positive effect (β = 1.805, P < 0.05). Both models accounted for a medium amount of the total variance in the response variable (Nagelkerke R2 = 51–52%). Results suggest that habitat use by pudu deer is affected by human perturbation and native forest fragmentation. Our findings indicate that maintaining a more continuous native forest or areas of native forest located far from human settlements could represent an important strategy for improving the long-term survival of the species.

Teratologies can provide relevant information about invertebrate development and the underlying morphogenetic processes. However, their study has been scarcely addressed in taxa such as myriapods. In this article, a review of the morphological anomalies documented in Chilean myriapods is carried out and new morphological anomalies are recorded in Akymnopellis laevigata (Porat, 1876) and Akymnopellis platei (Attems, 1903) (Chilopoda, Scolopendromorpha, Scolopendridae) collected in the Coquimbo Region, Chile. Four morphological anomalies are documented in Chilean myriapods and two ternary schistomelias and one atrophy are described, recording teratological specimens for the first time in northern Chile. The recurrence of malformations and the possible origin of teratologies are discussed.

The paper discusses the attenuation of rotor angle oscillations in micro-synchronous generators in the presence of a fault, operating near PV generation units following a proposed control scheme. The X/R ratio is lower in distribution systems, making power transfer more difficult, especially during conditions of rapid active power delivery. In this context, this paper proposes a post-fault active power recovery scheme to be applied to PV units in a distribution system, specifically designed to act during severe disturbances. The proposed control scheme implements a DC voltage reference ramp during the active power recovery stage of the PV unit, aiming to prevent a sudden increase in the inverter’s active power output. In distribution systems with limited transfer capacity, the increased active power of the inverter could flow into the synchronous machine, leading to an increase in rotor angle oscillations-a phenomenon not observed in a high-voltage transmission grid. The proposed scheme is experimentally tested, comparing its performance against low-voltage ride-through (LVRT) requirements established by various grid codes. The results demonstrate the effectiveness of the proposed control scheme in reducing synchronous machine post-fault rotor angle oscillations, performing better when compared to control schemes mandated by various grid codes.

Timber construction experiences a growing trend in different countries due to its inherent environmental benefits and proven lateral load performance. However, most of the previous studies on structural and seismic performance have focused on undamaged structures without any signs of deterioration. This paper focuses on the analysis of the effects of the initial damage state on the seismic response and fragility of a five-story CLT building designed under a force-based approach. A detailed 3D finite element model was developed and validated through experimental data in order to perform incremental dynamic analyses that considered different arbitrarily imposed initial damage states. The residual response and the fragility functions are analyzed to characterize the impact of the initial state on seismic behavior. The results of this work highlight the need to properly consider the effect of previous load actions for the seismic performance evaluation during the operating life of CLT structures. Findings suggest that the initial state can significantly modify the probability of reaching a given limit state. Moreover, it was found that if the initial damage is defined as severe, the collapse margin ratio is reduced by 58.8% compared to the case in which the initial state is undamaged.

In the present technological landscape of smart grids, where renewable energy-based distributed generation units inject power at various distribution nodes, ensuring optimal operation and preventing voltage instability require autonomous and intelligent actuation at distribution level. Fast and reliable algorithms for computing power flow are crucial in numerical simulations that aid the design of closed-loop actuation strategies, contributing to the advancement of smart grid technologies. In this context, we present a unified complex variables formulation of distribution circuits that allows a comprehensive analytic comparison between various classic and contemporary power flow methods, including the traditional Newton–Raphson, Gauss–Seidel, and Iwamoto methodologies, as well as modern successive current approximations and fixed-point strategies. As a result of this comparative process, we are able to contribute novel alternatives that avoid costly matrix operations, thus improving the algorithmic performance in terms of convergence speed and iterations count. Extensive numerical tests, using open-source software and standard desktop hardware to run realistic dynamic simulations, show that the proposed algorithms surpass classic and modern methods in terms of convergence speed, saving up to a $90\%$ of effective computation time.

Mathematical models are the most cost‐effective way to learn about a system. The objective of this study was to identify the model that best describes data for extraction kinetics of flavonoids released from cocoa (Theobroma cacao L.) bean shells (CBS) with nine choline chloride‐based deep eutectic solvent (ChCl‐DES) aqueous solutions. Conventional solvent extraction with an ethanol aqueous solution was used to compare results. Four phenomenological and two empirical models were compared. Flavonoid concentration in the extracts was measured spectrophotometrically and fitted by nonlinear regression. Model goodness‐of‐fit was evaluated by comparing the adjusted determination coefficient and root mean square error. All the studied models effectively captured the kinetic data by showing a coefficient of determination greater than 0.92. The DES composition influenced the most accurate model. The DES‐based extraction notably enhanced the washing and diffusion stages and improved the extraction process.

Waste production is a worldwide concern due to its adverse impact on the environment, as well as on the health of living beings. Sustainable development states the urgent need to implement actions to gradually replace fossil resources, including the use of renewable raw materials such as residues and secondary raw materials from other industries as a promising alternative to replace fossil resources. This research explores an approach focused on the design of renewable materials by developing a bio-based textile coating with the use of sawdust from radiata pine, which is the result of industrial wood transformation processes. The methodology adopted a transdisciplinary approach, integrating knowledge from design, engineering, and sociology disciplines. A perceived sawdust quality study was carried out in its original format, while two different coated textile substrates were developed, using knife-over-roller and spray coating processes, which were evaluated from user acceptance and functional performance points of views. Finally, a clothing prototype for workwear, using the bio-based coatings, was developed, employing a mono-material design concept (i.e., using the same material in all its forms). The results obtained from users and laboratory studies favour the knife-over-roller coating and the removable clothing design, which provides improved usability performance. The obtained conclusions highlight that transdisciplinary collaboration is essential to address complex challenges in the development of solutions, placing the design of material as a necessary prior action in the design process of final products.

Introduction In Chile, the prevalence of overweight among schoolchildren over the age of 5 is approximately 50%, one of the highest in the Americas region. This is largely influenced by the presence of inadequate food environments, characterized by limited access to healthy foods and a high availability of highly processed foods (HPF). This study analyzes food consumption in Chilean schoolchildren and the association of this with the Chilean Dietary Guidelines Based on Foods (DGBF) and the HPF consumption. Material and methods The sample (1,094 schoolchildren) was obtained from the baseline of the FONDEF IT18I0016 project, in Santiago-Chile. Anthropometry and socioeconomic data were measured. Dietary intake was assessed using a validated semi-quantitative frequency survey featuring images of food groups aligned with DGBF, as well as HPF. All data were collected by trained professional nutritionists. Associations between dependent and independent variables, and potential confounding factors were calculated using logistic regression models with stepwise backward/forward. A p < 0.05 was accepted as significant, using Stata 16.0. Results Most of the students (54.1%) were with malnutrition by excess and 20.0% exhibited abdominal obesity. Twenty percent of the students met the recommended intake for DGBF (fruits, vegetables, fish, milk and dairy products, legumes, water) and less than 5% did not consume any HPF. Consuming some sub-groups of HPF in moderate quantities (either no consumption or occasional consumption) increases the likelihood of meeting DGBF: candies and sweets (OR: 0.72; p = 0.04), pies with or without filling (OR: 0.63; p = 0.01), and salted snacks (OR: 0.67; p = 0.02). Conclusion Our results contribute to reaffirm the need to enhance healthy food consumption among schoolchildren and to discourage the intake of HPF, particularly focusing on specific sub-groups of HPF that may increase the risk of displacing the consumption of food groups recommended by the DGBF.

In this paper we consider the planar non-collinear central configurations with n bodies with power-law potentials like $\sum m_im_jr^{-a}$, $a>0$, in which is possible to remove one body and still have a central configuration. This kind of central configurations is called a (n, 1)-stacked central configuration. We prove that the unique planar (n, 1)-stacked central configuration is formed by a regular polygon with equal masses at the vertices and one arbitrary mass at the barycenter, for $4\le n <8$. However, our results depend on the value of a.

The paper presents the most comprehensive and large-scale global study to date on how higher education students perceived the use of ChatGPT in early 2024. With a sample of 23,218 students from 109 countries and territories, the study reveals that students primarily used ChatGPT for brainstorming, summarizing texts, and finding research articles, with a few using it for professional and creative writing. They found it useful for simplifying complex information and summarizing content, but less reliable for providing information and supporting classroom learning, though some considered its information clearer than that from peers and teachers. Moreover, students agreed on the need for AI regulations at all levels due to concerns about ChatGPT promoting cheating, plagiarism, and social isolation. However, they believed ChatGPT could potentially enhance their access to knowledge and improve their learning experience, study efficiency, and chances of achieving good grades. While ChatGPT was perceived as effective in potentially improving AI literacy, digital communication, and content creation skills, it was less useful for interpersonal communication, decision-making, numeracy, native language proficiency, and the development of critical thinking skills. Students also felt that ChatGPT would boost demand for AI-related skills and facilitate remote work without significantly impacting unemployment. Emotionally, students mostly felt positive using ChatGPT, with curiosity and calmness being the most common emotions. Further examinations reveal variations in students’ perceptions across different socio-demographic and geographic factors, with key factors influencing students’ use of ChatGPT also being identified. Higher education institutions’ managers and teachers may benefit from these findings while formulating the curricula and instructions/regulations for ChatGPT use, as well as when designing the teaching methods and assessment tools. Moreover, policymakers may also consider the findings when formulating strategies for secondary and higher education system development, especially in light of changing labor market needs and related digital skills development.

Invasive species have significantly impacted freshwater ecosystems in recent decades. The eastern mosquitofish Gambusia holbrooki Girard, 1859, the chameleon fish Australoheros facetus (Jenyns, 1842), and the sewage snail Physa acuta Draparnaud, 1805, have invaded numerous countries worldwide, including Chile. To date, these species have not been found in syntopy within this country. Through morphological and molecular analyses, we achieved precise taxonomic identification of these three species in Lake Santa Elena, Ñuble Region, thereby filling the gap in their invasive ranges. Given the high potential for the spread of these invasive species, we recommend conducting additional surveys in other water bodies in Chile where they have not been previously recorded. Considering that there are rare cases successful in eradicating invasive species, priority should be given to protecting non-invaded water bodies from new invasions though it is also important to make persistent efforts for conservation of native communities in the invaded ecosystems.

El estudio propone caracterizar la enseñanza-aprendizaje de sismos en una secuencia didáctica para analizar las explicaciones científicas del estudiantado de tercer año de Ciencias para la Ciudadanía en un colegio polivalente en zona centro sur, Chile. La investigación sigue un enfoque cualitativo según Design Based Research (DBR), por tanto, los diseños para el aprendizaje están contextualizados. El diseño utilizó como estrategia la modelización y se desarrolló en cuatro fases: compartir saberes, poner a prueba los saberes, estructurar el aprendizaje nuclear, aplicar el aprendizaje nuclear. Las explicaciones se categorizaron según desempeño en tres niveles: descriptivo; relacional; causal y los modelos escolares de representar e interpretar y modelo de aplicar. Los resultados indican que a través de las actividades de aprendizaje propuestas el estudiantado progresó desde un modelo de representación estático de la tierra a un modelo final dinámico. Las explicaciones en un nivel inicial descriptivo cambiaron a un nivel causal debido a que incorporaron causa-efecto sobre sismos basados en evidencias científicas, además, el estudiantado expresó acciones preventivas de mitigación personal y ciudadana en caso de ocurrencia de sismos.

Global awareness of introduced species as one of the primary drivers of biodiversity change—causing environmental impacts, and economic and social effects—emphasizes the need to enhance our understanding of these species. Developing a comprehensive database will enable policymakers to identify global bioinvasion patterns and strengthen their capacity to manage them effectively. Aquatic mollusks play a crucial role in the ecosystems they inhabit, influencing food webs and nutrient cycling, and habitat formation and modification. They are also the dominant group in aquaculture, contributing significantly to the economy while also causing economic losses through macrofouling and posing health risks. Despite their importance, information on the introduction, establishment, and dispersal of mollusk species in South America remains scarce and is often confined to the grey literature. With the aim of organizing, increasing, and strengthening the knowledge of non-native and transplanted mollusks in general and aquatic mollusks in particular, 29 specialists in the introduced mollusks of South America, from seven countries, have been working collaboratively since 2016. Each member contributes expertise, data, and bibliographic resources to build the status of the introduced mollusks in South America and provide critical information to prevent future introductions and transplants. In aquatic environments, 41 non-native mollusk species and 18 transplanted species have been identified. Among them, the bivalve Limnoperna fortunei stands out with the greatest economic effect, while the gastropods Lymnaeidae and Thiaridae represent significant health concerns. Although this research represents a major step forward, it also highlights challenges such as the scarcity of taxonomic studies and the limited investigation of vast areas in South America. The information compiled in this review serves as a resource for researchers, policymakers, and the general public when addressing mollusk bioinvasions in South America.

Laminated veneer lumber panels (LVL) are engineered wood products suitable for application in construction contexts. However, LVL panels have some deficient elastic properties (e.g., ${E}_{22}$) concerning other elastic properties (e.g., ${E}_{11}$ and ${G}_{12}$), which may cause problems in structural applications. Carbon and basalt fibers (CF and BF) are reinforcement alternatives for LVL panels, as they can be included in the interior or exterior wood veneer bonding process. This work aims to analyze the effect of incorporating CF and BF fibers in the orthotropic elastic properties of radiata pine LVL panels through a nondestructive method based on transverse vibration tests and model updating techniques. Accordingly, 20 LVL panels of 15 mm thickness were fabricated and tested with different reinforcing fibers and adhesives. Then, some relevant panels’ dynamic properties were identified through experimental modal analysis. Finally, three relevant panels’ orthotropic elastic properties were estimated simultaneously using finite-element model updating techniques and Python-based deterministic calibration scripts. The results suggest that the reinforced LVL panels obtained significant increases in their orthotropic elastic properties, in the order of 22%, 333%, and 27% for ${E}_{11}$, ${E}_{22}$, and ${G}_{12}$, respectively. These results show the effectiveness of the type of reinforcement applied and the potential application of the nondestructive evaluation method in other contexts.