Search Results (660)

We propose a hybrid framework that integrates instance clustering with Automatic Generation of Algorithms (AGA) to produce specialized algorithms for classes of Multidimensional Knapsack Problem (MKP) instances. This approach is highly relevant given the latest trends in AI, where Large Language Models (LLMs) are actively being used to automate and refine algorithm design through evolutionary frameworks. Our method utilizes a feature-based representation of 328 MKP instances and evaluates K-means, HDBSCAN, and random clustering to produce 11 clusters per method. For each cluster, a master optimization problem was solved using Genetic Programming, evolving algorithms encoded as syntax trees. Fitness was measured as relative error against known optima, a similar objective to those being tackled in LLM-driven optimization. Experimental and statistical analyses demonstrate that clustering-guided AGA significantly reduces average relative error and accelerates convergence compared with AGA trained on randomly grouped instances. K-means produced the most consistent cluster-specialization. Cross-cluster evaluation reveals a trade-off between specialization and generalization. The results demonstrate that clustering prior to AGA is a practical preprocessing step for designing automated algorithms in NP-hard combinatorial problems, paving the way for advanced methodologies that incorporate AI techniques. Full article

Cities host a heterogeneous composition of native and exotic plants, yet the spatial distribution of plant richness and its drivers remain poorly understood. We evaluated the influence of the center-edge gradient, along the environmental gradient from the historic city center to the urban edge, and habitat type, reflecting local conditions, on plant richness in Santiago, Chile. Sidewalks, parks, and vacant lots (n = 234 per habitat type) were randomly sampled across varying distances from the historic center and urban edge, recording neighborhood socioeconomic level and municipality. Four richness metrics were analyzed using generalized linear mixed models (GLMMs): total richness, richness by origin (native or exotic), and richness by life form (trees, shrubs, or herbs), considering habitat type, socioeconomic level, and distances as fixed effects and municipality as a random effect. We recorded 699 species (13% native and 87% exotic; 23% trees, 20% shrubs, and 56% herbs). Distances to the city center and urban edge had no significant effect, whereas habitat type emerged as the primary determinant: sidewalks exhibited higher total, native, and exotic richness with more trees and shrubs, whereas vacant lots were dominated by herbs. These patterns indicate that floristic richness is distributed in a mosaic, independent of urban gradients. Given the importance of Santiago’s Mediterranean region as a biodiversity hotspot, the low representation of native species is concerning. Increasing their presence and associated ecosystem services requires tailored interventions for each habitat type. Full article

Forests play a critical role in regulating hydrological processes and reducing soil erosion and sediment load. However, climate change has increased the frequency and severity of wildfires, which can significantly impact these ecosystem services. A historical megafire burned in January of 2017 in Central Chile, affecting the Purapel in Sauzal experimental watershed (an area dominated by Pinus radiata plantations), providing a unique opportunity to study post-fire sediment load dynamics. We hypothesized that sediment load would significantly increase following the wildfire, especially in areas with exotic commercial plantations. To test this, we analyzed daily sediment load and streamflow data collected the Purapel River during the 1991–2018 period, as well as other variables. Descriptive statistics and a sediment rating curve model were used to assess temporal variations in sediment load. Contrary to expectations, results showed no significant increase in sediment concentration following the devastating 2017 wildfire event. In fact, the Mann–Kendall test revealed a significant decreasing trend in winter sediment production over the study period. These findings may be explained by a reduction in precipitation during the mega-drought of the 2010s and, importantly, a rapid and dense post-fire pine seedling regeneration. This study highlights the complex interactions between climate, vegetation, and geomorphic processes, as well as the need for further research on post-fire sediment dynamics in Mediterranean plantation forests. Full article

Background: Cardiovascular diseases (CVDs) are the leading cause of morbidity and mortality worldwide, with metabolic syndrome and its risk factors contributing substantially to cases in Latin America. In southern Chile, obesity, dyslipidemia, and sedentary behavior are highly prevalent, yet comprehensive baseline data on these factors are scarce. Establishing regional cardiometabolic profiles is crucial to inform prevention strategies. Objective: To describe the RIO-Study protocol and characterize the baseline cardiometabolic profile of adults from Valdivia, southern Chile. Methods: The RIO-Study is a randomized, double-blind, placebo-controlled, crossover clinical trial evaluating the effects of nutritional doses of seaweed-derived omega-3 fatty acids on lipid metabolism, inflammation, and molecular lipid regulators in adults with overweight/obesity. The protocol includes a standardized high-fat breakfast challenge and repeated postprandial blood sampling to assess dynamic lipid responses. Screening procedures comprised blood pressure measurement, fasting blood sampling, body composition by bioelectrical impedance, and health and lifestyle questionnaires. Results: Among screened participants, 91% presented overweight/obesity and 55% presented central adiposity, exceeding regional cardiometabolic risk thresholds (waist circumference ≥ 90 cm in men, ≥80 cm in women). Men exhibited higher waist circumference (100 ± 10.8 vs. 91.6 ± 11.9 cm), waist-to-hip ratio (0.99 ± 0.08 vs. 0.92 ± 0.07), systolic blood pressure (130 ± 12.0 vs. 122 ± 13.4 mmHg), triglycerides (168 ± 84.7 vs. 122 ± 64.9 mg/dL), VLDL-C (33.7 ± 17.2 vs. 24.4 ± 13.0 mg/dL), and sedentary time (8.1 ± 2.3 vs. 6.8 ± 2.3 h/day). Women had greater total body fat (39.7 ± 4.75% vs. 31.1 ± 5.30%), higher HDL-C (56.6 ± 13.3 vs. 46.9 ± 9.39 mg/dL), and more often had normal weight (13% vs. 0%). Conclusions: The RIO-Study provides novel insights into cardiometabolic risk and will elucidate the effects of nutritional omega-3 supplementation in a high-risk Chilean population. Full article

80 years of Chilean rock art research, from its early descriptive stages in the 1940s to the present-day integration of relational ontologies, archaeometric techniques, and interdisciplinary perspectives, is reviewed. 562 publications are analysed, covering four major regions: the Arid North, Semi-Arid North, South-Central, and Southernmost Chile. Drawing from a systematically constructed corpus, we trace the evolution of research questions, theoretical orientations, and methodologies over time, with attention to regional trends and institutional dynamics. Results reveal a gradual shift from typological classification toward more complex approaches addressing mobility, landscape, coloniality, visual agency, and human/non-human relationships. The Arid North emerges as the primary centre of innovation, while southern regions remain in exploratory stages despite recent advances. Comparison with global research trajectories shows how Chile’s situated approaches—marked by decentralisation, theoretical pluralism, and critical reflection—contribute to decolonial and southern perspectives in rock art studies. Rather than reproducing hegemonic models, Chilean scholarship offers alternative epistemologies rooted in context-specific materiality and historical processes. The review highlights the potential of Chilean rock art research to expand the theoretical and methodological horizons of the discipline, positioning it as a fertile field for dialogue with contemporary archaeology and global visual studies. Full article

Calafate berry, an ancient perennial shrub of South America (Chile and Argentina), produces a high antioxidant capacity berry with a high polyphenol (1344.2–6553 mg GAE/100 g d.w.) and anthocyanin (26.5–80 mg C-3-G/100 g d.w.) content. The beneficial effects of calafate berries on human health are related to the anti-inflammatory, hypoglycemic, anticancer, and antioxidant properties that the berries possess, which have been confirmed through evidence to date, primarily from in vitro, ex vivo, and animal studies. Several investigations have shown a relationship between the consumption of calafate and a reduction in the risk of contracting cardiovascular diseases (CVD). This was evident in changes in plasma level biomarkers related to CVD, such as thrombomodulin (−24%), adiponectin (+68%), sE-selectin (−34%), sICAM-1 (−24%) and proMMP-9 (−31%), and changes in the production of OH radicals in plasma (−17%) after calafate intake. Calafate may have an antithrombotic role that supports cardiovascular health by lowering the Atherogenic and Cardiovascular Risk Indices. Various authors indicate delphinidin-3-glucoside (384–386 mg/100 g) as the primary bioactive compound responsible for the beneficial properties of Calafate. Although some studies report calafate’s health benefits, scientific evidence, especially in humans, remains limited. Meanwhile, Chile is working to domesticate and cultivate calafate, aiming to turn it from a wild native berry into a sustainable crop for use in the antioxidants and nutraceuticals industry. The lack of human clinical trials emphasizes the need for future research to validate calafate’s health benefits berry. Full article

In north-central Chile, water reuse is essential due to the arid climate. Mining tailings ponds offer a promising opportunity for water recovery; however, the water quality often fails to meet the environmental standards for discharging liquid waste into marine and inland surface waters. This study proposes a bioreactor-based technology for softening tailings water while also addressing the need to quantify its sustainability impacts. To achieve that, an evaluation of the environmental and social performance of the bioreactor is conducted, comparing it with established softening methods, using an industrial ecology approach. This evaluation aims to explore scalable alternatives for sustainable water management. Environmental impacts are quantified using the ReCiPe 2016, with data sourced from Ecoinvent v3.8 and Agrifootprint databases. Social risks are assessed through the Social Hotspot Database modeling in SimaPro 9.5.0.2. The results indicate that the bioreactor demonstrates greater sustainability compared to membrane-based systems, reducing greenhouse gas emissions by more than 95%. It also registers the lowest aggregated social risks due to its minimal energy intensity, lack of hazardous chemicals, and simplified infrastructure. In contrast, reverse osmosis, while delivering higher quality permeate, results in the highest environmental burdens and occupational hazards. This research validates the bioreactor as an enabler of industrial ecology, transforming tailings water into a circular resource. Full article

Background: TRPC6 is recognized as a therapeutically relevant cation channel, whose activation is governed by specific ligand–pocket interactions. Methods: An integrated in silico workflow was employed, comprising structure-based docking, 100-nanosecond molecular dynamics (MD) simulations, and MM-GBSA calculations. Benzoic-acid–based compounds were designed and prioritized for binding to the TRPC6 pocket, using a known literature agonist as a reference for benchmarking. Results: Within the compound series, BT11 was found to exhibit a representative interaction profile, characterized by a key hydrogen bond with Trp680 (~64% occupancy), persistent salt-bridge interactions with Lys676 and Lys698, and π–π stacking with Phe675 and Phe679. A favorable docking score (−11.45 kcal/mol) was obtained for BT11, along with a lower complex RMSD during MD simulations (0.6–4.8 Å), compared with the reference compound (0.8–7.2 Å). A reduction in solvent-accessible surface area (SASA) after ~60 ns was also observed, suggesting decreased water penetration. The most favorable binding energy was predicted for BT11 by MM-GBSA (−67.72 kcal/mol), while SOH95 also ranked highly and slightly outperformed the reference. Conclusions: These convergent computational analyses support the identification of benzoic-acid–derived chemotypes as potential TRPC6 ligands. Testable hypotheses are proposed, along with structure–activity relationship (SAR) guidelines, to inform experimental validation and guide the design of next-generation analogs. Full article

Background: Leishmania amazonensis, one of the causative agents of cutaneous leishmaniasis, is responsible for a neglected tropical disease affecting nearly one million individuals worldwide. Although clinical treatments are available, their effectiveness is often compromised by high toxicity and limited selectivity. Methods: From a database, 64 chalcone derivatives were studied using Comparative Molecular Similarity Indices Analysis (CoMSIA) and Hansch analysis (2D-QSAR) to construct predictive computational models. Internal and external validation criteria were applied to identify structural determinants associated with antileishmanial activity. Based on these insights, twelve novel quinoline–chalcone hybrids were designed, synthesized, and biologically evaluated against L. amazonensis. Results: The most robust CoMSIA model combined steric and hydrogen-bond acceptor fields (CoMSIA-SA), while Hansch analysis highlighted electronic descriptors—specifically LUMO energy and the global electrophilicity index—as critical for parasite growth inhibition. Guided by these computational findings, a new series of 12 hybrid quinoline–chalcone derivatives (E001–E012) was synthesized through a two-step procedure, achieving overall yields of 43–71%. Biological assays demonstrated that four compounds displayed inhibitory activity comparable to amphotericin B. Furthermore, physicochemical profiling and in silico pharmacokinetic predictions for the most active compounds (E003, E005, E006, and E011) indicated favorable biocompatibility and drug-like properties. Conclusions: These results underscore the value of an integrative computational–experimental approach in the rational design of next-generation L. amazonensis inhibitors, reinforcing chalcone-based scaffolds as promising pharmacophoric frameworks for antileishmanial drug discovery. Full article

Heliaster has long been considered to comprise seven nominal species of starfish distributed across the Eastern Pacific, from Baja California (Mexico) southward to central Chile. Along the southeastern Pacific coast, three taxa have been traditionally recognized: H. helianthus (Paita, northern Peru, to Concepción, central-southern Chile), H. polybrachius (Mexico to Perú), and H. canopus (Juan Fernández Archipelago and Desventuradas Islands). However, extensive morphological overlap among these forms has cast doubt on the validity of H. canopus, with some authors treating it as a synonym for H. helianthus. To clarify this ambiguity, we applied an integrative framework combining detailed morphometrics, phylogenetic inference from mitochondrial (COI) and nuclear (H3) markers, and two species delimitation approaches (bPTP and ASAP). Our sampling spanned Peru, continental Chile, and the oceanic islands of Juan Fernández and Desventuradas. Variation in ray number and relative arm length among H. helianthus, H. canopus, and H. polybrachius proved allometric, scaling strongly with body diameter rather than indicating discrete species boundaries. Molecular data show >95% sequence similarity across all nominal taxa and recover a single, well-supported clade; bPTP and ASAP likewise support one Heliaster lineage throughout the southeastern Pacific, corresponding to H. helianthus. Accordingly, we redescribe H. helianthus, designate a neotype from Quintay, Chile, and formally synonymize H. canopus and H. polybrachius under H. helianthus. Our results indicate that a single species spans the Eastern Pacific from Ecuador and Peru to central-southern Chile, including offshore islands, underscoring the value of integrative taxonomy for robust delimitation and accurate biodiversity assessments in marine invertebrates. Full article

This study presents a comprehensive latitudinal analysis of air particulate matter (PM) across an 1400 km pollution corridor spanning Chile’s central-southern zone. We systematically analyzed PM_2.5 and PM₁₀ concentrations across eight major urban centers (2014–2015), providing crucial pre-Paris Agreement baseline data for South America’s most extensive air quality monitoring network. Our analysis reveals significant pollution gradients, with Coyhaique ranking one of the world’s most severely polluted cities (95th percentile globally, WHO database) and demonstrating an extreme 86% fine particulate matter ratio that far exceeds international urban standards. Residential wood combustion (RWC) demonstrates systematic correlations with fine PM concentrations (R² > 0.96), suggesting RWC is the dominant pollution driver across multiple climate zones. The documented pollution patterns represent a concerning continental-scale environmental pattern, with 4900–6500 annual premature deaths directly attributable to PM_2.5 exposure-one of the highest per-capita pollution mortality rates in South America. This work provides a methodological framework applicable to mountain-valley pollution systems globally while addressing critical knowledge gaps in regional air quality science. The evidence indicates the need for urgent implementation of comprehensive wood combustion control strategies and positions this research as essential baseline documentation for both national air quality policy and international climate change assessment frameworks. Full article

CB₁ agonist compounds may be potential drug candidates for the treatment of gliomas, as they have been shown to inhibit tumor cell proliferation, induce apoptosis, and reduce angiogenesis in various preclinical models. Their ability to modulate the endocannabinoid system suggests a promising therapeutic approach for targeting glioma growth and progression. Herein, we report the design, synthesis, biological studies, and bioinformatics assays of novel benzo[d]imidazole–naphthalen-arylmethanone regioisomers with affinity for the CB₁ receptor, as well as propose an indirect methodology to evaluate their presumed CB₁ agonist activity. Compounds that showed a propensity for binding to the CB₁ receptor were regioisomers 4d, 5b, 5e, 5f, and 5f′. Likewise, derivatives that displaced more than 50% of the radioligand [³H]CP-55940 at the CB₁ receptor were subjected to in vitro viability experiments. Compounds 4d, 5b, 5e, and 5f′ showed toxicity against U87MG cells (malignant glioma) in a considerable percentage. Notably, compound 5f′ showed CB₁ affinity, with a K_i of 2.12 µM, and was selectively toxic to U87MG cells, which highly express the CB₁ receptor, while exhibiting no toxicity toward the healthy HEK293 cell line, which expresses both cannabinoid receptors at negligible levels. Docking studies at the CB₁ orthosteric site indicate that 5f′ forms π-π interactions, a T-shaped interaction, and hydrogen bonding through the oxygen atom of the furan ring. Biologically, our experimental indirect model-based on a simple viability assay is supported by well-established evidence that activation of CB₁ and CB₂ receptors by agonists induces cell death and inhibits tumor cell growth. Structurally, we conclude that the presence of a furan ring at the 2-position of the benzo[d]imidazole core is beneficial for the development of new ligands with potential CB₁ agonist activity. Full article

This study examines the financial behavior of university students in Economics, Business Administration, and Accounting in Tegucigalpa, Honduras, using the FB–13 instrument. Exploratory and confirmatory factor analyses validate a three-dimensional structure: (1) financial planning and control, (2) savings and financial preparation, and (3) fulfillment of obligations, with high internal consistency (α = 0.915), supporting its psychometric robustness in Latin American academic contexts. Based on a sample of 714 students with diversity in gender, age, work experience, and parental status, the analyses confirmed that the FB–13 model best fits a three-factor structure. Significant correlations were identified between financial behavior and experiential variables such as age, work experience, and parenthood, while traditional sociodemographic attributes such as gender, residence, marital status, employment, and educational level showed limited associations. These findings suggest that personal experiences have a greater influence on the configuration of financial practices than conventional demographic categories. The study acknowledges limitations related to cross-sectional design, non-probabilistic sampling, and self-reported data, yet these do not diminish its contributions. By validating the FB–13 in Honduras, the research offers comparative evidence and promotes cultural diversity in financial behavior literature. Future research should move toward longitudinal and qualitative studies that explore the role of family dynamics, work contexts, and personal aspirations in responsible financial behaviors. Full article

Brassinosteroid analogs with heterocyclic rings in the side chain are interesting because important biological activity has been shown by these compounds. Thus, herein, five 23-24-dinorcholane BR analogs with a heterocyclic ester function at C-22 were synthesized and fully characterized by different spectroscopic techniques. The acylation reaction at C-22, which is a key synthetic step, was carried out by two different methods, namely acylation with heterocyclic acid chlorides and Steglich esterification reaction. In both cases, the acyl derivatives were obtained with good yields. Additionally, a preliminary molecular docking study of BRI1–BAK1 complexes formed by these analogs and brassinolide was performed to estimate what their biological activity would be. Results indicate that the complex formed by the analog 36, which has an indole group in the side chain, within the active site of BRI1–BAK1 is more stable than that formed by brassinolide. Additionally, molecular docking of a derivative having a benzoate function at C-22 and a F atom in the ortho position, 23, shows a similar pose and interactions at the active site but the highest binding energy. As 23 has shown similar activity to brassinolide in the Rice Lamina Inclination Test, it is expected that 36 will also exhibit similar behavior. Full article

In Santiago, Chile, urban plants are highly vulnerable to drought or climate change. We hypothesize that would find high growth and survival rates in conditions of water scarcity among native species of central Chile. The goal was to determine the effect of the year season and an irrigation gradient on the survival and growth of native plant, in order to evaluate potential plant for use in urban green areas of central Chile. Four plots of 20 m² were located in the Santiago center. In June 2024 twelve species were planted and from November 2024 to March 2025 were irrigated with 13.3, 10.1, 1.7 and 1.4 L/m²/day. The GLM and Kaplan–Meier survival analyses were used. Shoot growth rate was highly variable among species, among irrigation treatments applied, and among year seasons. Eight species showed water-related growth and shoot growth during the winter was very small and higher in spring. Two species showed evidence of water-related survival; in the other 10 species, no significant differences were found between irrigation treatments. Winter was the season with the highest survival rates for eleven species. In conclusion, the results suggest that native plants can achieve high survival rates with limited irrigation. This highlights their potential for use in the urban area in Mediterranean-type climates where rainfall is expected to be low due to climate change. Full article