Search Results (367)

Berries are an excellent source of bioactive compounds, particularly polyphenols, and have been widely used in folk medicine by the Mapuche people of southern Chile. In this study, a hydroalcoholic extract of Berberis congestiflora Gay (BE) was analyzed to determine its phytochemical composition and to evaluate its antioxidant capacity, vasorelaxant effects in rat aortas, and inhibitory activity on enzymes related to chronic non-communicable diseases, including exploration of a possible vasodilatory mechanism in isolated rat aortas. Antioxidant activity was assessed using Oxygen Radical Absorbance Capacity (ORAC), DPPH (2,2-diphenyl-1-picrylhydrazyl), and ABTS (2,2-azinobis-(3-ethylbenzothiazolin-6-sulfonic acid)) radical scavenging assays, as well as ferric reducing antioxidant power (FRAP). Vascular responses to the Berberis extract were studied using isometric tension recordings in an ex vivo rat thoracic aortic ring model, and the chemical constituents of BE were identified for the first time by HPLC-DAD-MS. The extract itself produced a dose-dependent contraction at 100 and 1000 µg/mL and induced relaxation in phenylephrine-precontracted aortas at the same concentrations, with a maximum contraction of 71% and maximum relaxation of 70% at 1000 µg/mL. Mechanistically, the extract triggered calcium-mediated contraction primarily through calcium release from the sarcoplasmic reticulum and, to a lesser degree, via extracellular Ca²⁺ influx, while its relaxant effect depended on an intact endothelium and activation of the NO/cGMP pathway. In addition, the extract showed inhibitory activity against cholinesterase, glucosidase, and amylase, with IC₅₀ values of 7.33 ± 0.32, 243.23 ± 0.3, and 27.21 ± 0.03 µg/mL, respectively, and docking studies were carried out for selected berry compounds. Overall, these findings indicate that these berries are a rich source of bioactive constituents with antioxidant properties and endothelium-dependent vasodilator effects, supporting their traditional use and highlighting their potential as enzyme inhibitors and as promising candidates for the development of phytotherapeutic products, particularly as supplements for chronic disease management. Full article

Background/Objectives: The genus Tristerix comprises at least ten species, found from southern Chile to Colombia in South America. In Chile, several species of these hemiparasitic plants are known as quitral or quintral. Quitral, mainly T. corymbosus (syn. T. tetrandus), is used in alternative medicine for its anti-inflammatory, digestive, hemostatic, hypocholesterolemic, and wound-healing properties. This study investigates the phytochemical composition and antimicrobial properties of T. corymbosus. Methods: A hydroalcoholic extract of T. corymbosus was prepared from leaves and small branches. The addition of methanol, on the extract, produced precipitation allowing us to isolate a methanol-soluble fraction, a brown powder obtained after filtration, and a tar-like residue remaining in the flask. These fractions were resuspended and tested for antimicrobial activity. Results: All fractions showed activity against Streptococcus pyogenes, but not E. coli. The brown powder exhibits the strongest potency against Gram-positive bacteria, some Gram-negative and C. albicans. HPLC-MS analysis revealed presence of lipidic compounds with surfactant properties. Conclusions: The abundant lipidic molecules present in the analyzed fraction likely account for the antimicrobial effects through affecting membrane structure of microorganisms supporting the traditional wound-healing uses of T. corymbosus in ancestral medicine. Full article

Assessing the dynamics between native forests and exotic tree plantations is key to understanding the drivers of native forest transformation and conservation challenges. We examined these dynamics across four zones in the Los Ríos and Los Lagos regions of southern Chile: the Coastal Range, Central Valley, Andes, and Chiloé. Changes from 2002–2012 and 2012–2022 were analyzed using satellite image classifications and landscape metrics (total area, mean patch size, number of patches, patch density, mean Euclidean nearest-neighbor distance). In both periods, in zones with strong human influence, such as the Coastal Range and Central Valley, native forest area decreased and became more fragmented, whereas exotic tree plantations initially expanded and then declined, resulting in a net increase. Transitions between native forests and exotic plantations showed strong bidirectional substitutions. In less disturbed zones, such as the Andes and Chiloé, native forests expanded in area and connectivity. Overall, native forest cover increased in the Andes (+12.85 km²) and Chiloé. (+6.19 km²) but declined in the Coastal Range (−0.65 km²) and Central Valley (−7.75 km²), whereas exotic plantations showed a net expansion across all zones. These contrasting trajectories underscore the need for reliable monitoring tools to support effective forest management. Full article

Interactions between surface water and groundwater in arid regions regulate their response to climate and human impacts. In the salar systems of the Altiplano-Puna plateau (Bolivia, Chile, Argentina), understanding how surface waters connect to groundwater is crucial for accurate modeling and assessment. This study introduces new data and analysis using subsurface thermal profiles and modeling to identify flow patterns and possible surface water links. We document, to our knowledge, for the first time in the literature, deep-seated cooling of the subsurface caused by extreme evaporation rates. The subsurface is cooled by 4–5 degrees Celsius below the mean annual air temperature to depths greater than 50 m, even though groundwater inflow waters are elevated by 10 degrees °C due to geothermal heating. Three thermal zones are observed along the southern edge of Salar de Atacama, with temperature dropping from 28 °C to about 12 °C over 2.5 km. A 2D numerical model of groundwater and heat flow was developed to test various hydrological scenarios and understand the factors controlling the thermal regime. Two flow scenarios at the southern margin were examined: a diffuse flow model with uniform flow and flux to the surface and a focused flow model with preferential discharge at a topographic slope break. Results indicate that the focused flow scenario matches thermal data, with warm inflow water discharging into a transition zone between freshwater and brine, cooling through evaporation, re-infiltration, and surface flow, then re-emerging near lagoons at the halite nucleus margin. This research offers valuable insights into the groundwater hydraulics in the Salar de Atacama and can aid in monitoring environmental changes causally linked to lithium mining and upgradient freshwater extraction. Full article

Background/Objectives: Strengthening management competencies are essential to ensure effective and equitable Primary Health Care (PHC) systems. Emerging perspectives suggest that effective leadership in PHC could benefit from integrating cognitive, emotional, and social competencies. Although there is existing evidence on the required competencies worldwide and the characterization of PHC managers in Chile, no study has yet developed or validated a specific competency profile for these positions. This study developed and validated a competency profile for PHC managers to provide an evidence-based and context-specific tool for leadership, training, and evaluation. Methods: A mixed-method observational study based on expert judgment was conducted across three Chilean macrozones (northern, central, and southern), involving 36 professionals with recognized experience in PHC management identified through direct contact and snowball sampling. Quantitative validation through the Content Validity Index (CVI) confirmed high expert agreement (CVI ≥ 0.90), while thematic analysis of qualitative responses led to the inclusion of new areas. Results: The final profile comprises 47 competencies organized into knowledge, skills, and attitudes, emphasizing executive functions and social cognition and incorporating emerging domains such as emotional intelligence and institutional support. Beyond managerial relevance, the profile offers a structured framework for designing, implementing, and evaluating competency-based education and training in health sciences. Conclusions: These results also support leadership development and performance assessment, providing an evidence-based reference for professional training initiatives in PHC. This profile emphasizes that leadership development should not be limited to technical competencies, but also encompasses emotional, cognitive, and social dimensions essential for effective performance. Full article

The temperate rainforests of southern Chile host a rich diversity of plants traditionally used in medicine, yet their bioactive potential remains underexplored. This study evaluated the chemical composition, antioxidant capacity, antibacterial activity, and cell viability of ethanolic leaf extracts from Cissus striata (CS), Mitraria coccinea (MC), and Raukaua laetevirens (RL), compared with Buddleja globosa (BG), a well-known medicinal shrub. Extracts were obtained using 70% ethanol, ensuring high recovery of polyphenolic compounds while avoiding thermal degradation. The total phenolic content (TPC) was highest in CS, exceeding values reported for green tea, while MC exhibited the greatest total flavonoid content (TFC). HPLC–MS/MS analysis showed that RL was rich in rutin, while CS exhibited a higher quercetin content. Antioxidant activity assessed through ABTS, DPPH, and FRAP assays, was correlated with polyphenolic composition. CS showed the highest antioxidant potential, surpassing green tea by ~39%, as determined via FRAP, while MC and RL displayed capacities comparable to BG. Antibacterial activity assays demonstrated that MC inhibited Escherichia coli with a minimum inhibitory concentration (MIC) of 12.5 mg/mL, lower than that of ampicillin, whereas CS was highly active against Staphylococcus aureus, with an MIC of 0.39 mg/mL, equivalent to the activity exhibited by tetracycline. Cytotoxicity assays confirmed that the extracts did not reduce human cell viability, supporting the potential of Chilean native shrubs as safe, natural sources of antioxidants and antimicrobials for food and pharmaceutical applications. Full article

Several solutions are being explored to reduce methane intensity in dairy farms, but there is no consensus for commercial pastoral dairy systems in temperate zones. We evaluated the effects of essential oils (EO) supplementation on CH₄ intensity and performance in dairy cows within a commercial pasture-based system in southern Chile. Thirty multiparous cows were randomly assigned to a control group and a treated group, with a general average yield of 22.3 ± 5.37 kg/d and an average parity of 3.42 ± 1.13. The treated group received concentrate supplemented with a mixture of EOs. Enteric CH₄ emissions were measured using GreenFeed^®. Milk yield (kg/d), composition (% fat, % protein, urea, somatic cells), plasma biochemistry, and grassland proximal analysis (NIRs) were also evaluated. Results showed a significant increase in fat-corrected milk production (4.6 kg) in the treated group during the first trial period where the grassland was highly nutritious, offering 19.8% crude protein as well as a pool of long-chain fatty acids. Additionally, CH₄ intensity was significantly lower in the treated group (1.3 gCH₄/ECM) during the first phase. EO supplementation strategies represent a suitable non-invasive intervention suitable for commercial grassland-based systems in southern Chile that is strongly influenced by pasture quality. Full article

Background/Objectives: Understanding blood group antigen distribution is essential for transfusion safety and preventing alloimmunization in transfused patients. The ABO, RH1, and Kell blood group systems are among the most clinically significant due to their high immunogenic potential and their role in hemolytic transfusion reactions and hemolytic disease of the newborn. Despite their clinical significance, data on the phenotypic frequency of these samples in southern Chile are limited. This study aimed to identify the distribution of ABO, RH1, and Kell blood group systems among blood donors at the Centro de Sangre Concepción, adding regional data to the national transfusion medicine records. Methods: A retrospective, descriptive analysis was conducted using data from 59,318 blood donations collected in 2024 by the Concepción Blood Center, part of the Southern Transfusion Medicine Macronetwork in Chile. Blood typing for the ABO, RH1, and Kell antigen (KEL1) typing was performed in accordance with national regulations established by the Ministry of Health (MINSAL). Results: Blood group O was the most frequent (61.3%), followed by A (27.8%), B (9.0%), and AB (1.9%). RH1 positivity was observed in 94.47% of donors, and Kell positivity in 4.24%. The distribution of Kell phenotypes was comparable between men (4.38%) and women (4.11%), with the highest frequency in donors aged 27–52 years. Conclusions: The phenotypic distribution observed reflects national patterns and shows the genetic makeup of southern Chile. The low but important prevalence of Kell-positive donors emphasizes the need for systematic Kell antigen screening to prevent alloimmunization and improve transfusion safety. Full article

Widespread residential wood burning in southern Chile combined with cold climate conditions cause severe episodes of particulate matter (PM_2.5 and PM₁₀) pollution. In this study, we used logistic regression to predict daily exceedances of fine (PM_2.5) and coarse (PM₁₀) particulate levels at multiple urban sites, assessing model performance under different air quality standards. Results showed a clear latitudinal gradient in air pollution, with communities further south experiencing significantly higher PM levels and more frequent threshold exceedances, likely due to higher per capita firewood use and cooler temperatures. The logistic models achieved their best predictive accuracy under the strictest European (ESP) air quality standards (F1-scores up to ~0.72 for PM₁₀ and ~0.59 for PM_2.5), while Chile’s national (NCh) thresholds significantly underestimated pollution events. Additionally, annual per capita wood energy consumption in the far south was several times higher than in central Chile, contributing to disproportionately high emissions. These findings highlight the need to adopt more protective air quality standards and reduce wood-fueled emissions to improve early warning systems and decrease particulate exposure in southern Chile. Full article

Environmental filtering studies have revealed immense oceanic microbial diversity, yet the Southeast Pacific remains comparatively undersampled. We characterize the molecular diversity of phytoplankton across two biogeographic domains with contrasting oceanography—fjords and channels (41–53° S) versus the open Pacific (36–42° S)—where the frequency and intensity of harmful algal blooms (HABs) have increased. Using SSU rRNA metabarcoding, we retrieved community composition and biogeographic patterns for micro-phytoplankton. Diversity signals indicated broadly overlapping communities between domains with subtle shifts along hydrographic and nutrient gradients rather than sharp breaks. Phylogenetic resolution within bloom-forming genera recovered well-supported clades, and multiple ASVs matched historically relevant HAB taxa, including representatives of the Alexandrium complex, Dinophysis, Pseudo-nitzschia, and Karenia. Together, these results suggest that regional environmental filtering acts modestly at the community level while preserving clear signals of taxa of management concern. By providing a regionally resolved, DNA-based baseline for southern Chile’s fjords and adjacent open coast, this study helps fill the molecular diversity gap for the Southeast Pacific and supports improved HAB surveillance and ecosystem forecasting in a climate-sensitive seascape. Full article

Glacier mass balance and ice flow dynamics, strongly influenced by climatic variability, topography, and geological–structural controls, can be precisely characterized through in situ GPS measurements of surface ice velocity, though such data remain limited due to logistical challenges in field acquisition. This study presents direct measurements of surface ice velocity on Grey Glacier, a major outlet glacier of the Southern Patagonian Icefield (SPI) in Chile. Ice flow was monitored over a one-week period in late 2002 by tracking the displacement of six stakes installed on the glacier surface. The resulting velocity data reveal spatial patterns of surface flow that provide significant information for the comparison and validation of remote sensing observations, which is particularly relevant considering that the ice mass from which the data were collected has since disappeared due to glacier retreat. The combined use of ground-based and remote sensing methods is essential for advancing our understanding of glacier motion and behavior, particularly in the context of climate forcing. Full article

Background/Objectives: The objective of this study was to investigate current endodontic practice patterns and the adoption of newer technologies among dentists, endodontic specialists, and postgraduate students in Spain and Latin America. Methods: A cross-sectional survey was conducted using a structured 30-item questionnaire covering demographics, training, technology adoption (NiTi instrumentation, magnification, CBCT, irrigation adjuncts, bioceramic sealers), obturation techniques, irrigant selection, and clinical procedures. The survey was distributed through a professional Instagram account and WhatsApp groups of dentists, specialists, and postgraduate students. Participation was voluntary, anonymous, and restricted to qualified professionals. Data were collected via Google Forms, cleaned, and grouped into Spain, Mexico, Venezuela, Colombia, Southern Cone & Andes (Argentina, Chile, Peru, Ecuador, Bolivia), and other countries. Descriptive statistics were calculated, and intergroup comparisons were performed using Chi-square or Fisher’s exact tests with Bonferroni correction (p < 0.05). Multiple regression analyses were performed. Results: A total of 1358 valid responses were analyzed, distributed as follows: Spain (219), Mexico (353), Venezuela (162), Colombia (108), Southern Cone & Andes (260), and other countries (256). Most respondents (62.8%) had ≤10 years of experience, and 61.2% reported postgraduate training. Loupes (55.4%) were the most frequent magnification system, followed by microscopes (18.6%). Sodium hypochlorite (98.3%) was the irrigant of choice, commonly used with EDTA (83.5%) and, to a lesser extent, chlorhexidine (33.4%). Sonic (83.2%) and ultrasonic (52.9%) activation were frequent. Bioceramic sealers were used by 18.9%, while calcium hydroxide medication was applied by 37.4%. Specialists and master-level clinicians showed greater use of rotary NiTi systems, CBCT, magnification, and bioceramic sealers, whereas general practitioners relied more on manual instrumentation and single-cone obturation. Success was mainly verified by combined clinical and radiographic evaluation (86.7%). Spain demonstrated higher adoption of microscopes, warm vertical compaction, and CBCT. Conclusions: Core practices such as sodium hypochlorite irrigation and rubber dam use were widespread, while advanced technologies and irrigant protocols varied with training level and region. Continuous education remains essential to promote evidence-based practice and reduce disparities in endodontic innovation. Full article

Chile, the leading exporter of cherries (Prunus avium L.) in the southern hemisphere, faces sustained variations in precipitation patterns and high evaporative demand in its productive areas. The low availability of water during the period of highest environmental demand makes it essential to reduce or suspend irrigation applications. In this scenario, regulated deficit irrigation (RDI) after harvest is an efficient strategy for optimizing water use without compromising orchard yields. This study was conducted over three consecutive seasons in a traditional commercial orchard of ‘Santina’ cherry trees grafted onto Colt rootstock, evaluating the effect of two levels of RDI, moderate (MDI) and severe (SDI), on productive and ecophysiological parameters. Both treatments resulted in water savings of between 10% and 28%, without negatively affecting yield or fruit quality. The SDI treatment, despite reaching higher levels of cumulative water stress, improved intrinsic water use efficiency while maintaining stable photosynthetic efficiency. In addition, an increase in the abundance of fine roots and beneficial rhizosphere bacteria populations, such as Azospirillum and Bacillus, was observed, suggesting the activation of water resilience mechanisms mediated by plant–microbiota interaction, possibly associated with stress-induced ecological memory and microbial legacy effects. These results position after-harvest RDI as a sustainable tool for coping with climate variability and water scarcity in commercial cherry orchards. Full article

The relationships among subjective well-being (SWB), active travel, and the built and social environment have been rarely studied, especially in southern cities of Chile. The goal of this research is to investigate the connections between SWB and active travel, along with the associated social, built environment, and individual aspects in Temuco. Furthermore, due to the high levels of socioeconomic segregation (SES) in the city’s various urban neighborhoods, these relationships were studied independently based on two categories of neighborhoods, namely low-SES (NLSES) and high-SES (NHSES), which represent the majority of the city’s areas and population. To ascertain the number of responders in each SES category, a power analysis and simple random sampling were used. Consequently, 481 and 301 respondents were identified for NLSES and NHSES, respectively. A quantitative method and hierarchical multiple regression analysis were used to investigate the goals. The findings indicate that SWB is generally higher in NHSES than in NLSES. It was also found that there was a correlation between subjective well-being and several factors, such as age, some job-related categories, social cohesion, role models, and accessibility to shops, parks, and bus stops. Less SWB is a result of a higher unemployment rate in NLSES as opposed to NHSES. Additionally, a certain lifestyle type in NHSES demonstrated a positive correlation with SWB. Furthermore, there was a positive association found between the NHSES’s SWB and access to the bus network. This study provides evidence from a highly segregated Latin American city that shows how SWB is shaped differently across low- and high-SES neighborhoods. Temuco’s urban policymakers could use these data to improve SWB according to the different types of neighborhoods within this city. Full article

Student mobility in Higher Education Institutions (HIEs) significantly contributes to students’ personal and academic development. However, participation of people with disabilities remains limited due to various barriers. This study explores the perceptions of students with disabilities regarding mobility within universities in southern Chile. A descriptive qualitative approach was used, and semi-structured interviews and a focus group with 15 undergraduate students with diverse types of disabilities were conducted. Data analysis was conducted using reflexive thematic analysis. The results revealed that students with disabilities prefer one-semester mobility experiences, typically near the end of their studies. Identified barriers include a lack of physical and digital accessibility, insufficient implementation of reasonable adjustments in the teaching-learning process, and poor coordination in mobility management between institutions. Additionally, specific requirements emerged depending on the type of disability, such as the need for sign language interpreters for deaf individuals and additional medical insurance, subsidies for personal assistants, or accessible transportation for those with reduced mobility. This study highlights the importance of adopting inclusive and proactive policies to facilitate student mobility for individuals with disabilities and promote an accessibility ecosystem that involves all institutional stakeholders. Full article