Search Results (709)

The monophyletic lineage Phytoptidae s. str. (Acariformes, Eriophyoidea) comprises ~75 described species in 17 genera associated with angiosperms. Since the last keys to the world genera of Eriophyoidea were published in 2003, five new phytoptid genera have been described: Neoprothrix (Reis & Navia 2014), Borassia Chetverikov, Craemer 2017, Solenoplatilobus Chetverikov & Craemer 2016, Solenocristus Chetverikov et al. 2018, and Calventer Chetverikov 2025. Here, we provide an updated generic key for the tribe Sierraphytoptini (Phytoptidae), describe a new genus Nothofagicola, propose a new combination N. nothofagalis n. comb. (Chetverikov et al. 2018) (transferred from Solenocristus), report the first findings of N. cf nothofagalis from Nothofagus pumilio and No. antarctica from Southern Chile and describe three new species of Nothofagicola collected in Central Chile from stems of three Nothofagus species (Fagales: Nothofagaceae): N. alpinae n. sp. from No. alpina, N. bicristata n. sp. from No. alessandrii, and N. licanteniensis n. sp. from No. glauca. We also provide a corrigendum to our previous paper and state that the correct accession numbers for mitogenomic sequences of Leipothrix aegopodiae and L. cf knautiae are OR268621 and OR268622, respectively (vice versa in the paper). Full article

Mediterranean-type ecosystems (METs) occur on five continents and represent some of the most climatically constrained yet biologically rich regions on Earth. In these environments, legumes and their nitrogen-fixing rhizobial symbionts—including widely distributed genera such as Rhizobium, Bradyrhizobium, and Ensifer—play a pivotal role in sustaining plant productivity, nutrient cycling, and ecosystem resilience. This review synthesizes current knowledge on the environmental regulation of legume–Rhizobium symbiosis specifically within Mediterranean-type ecosystems, focusing on how nitrogen (N) and phosphorus (P) availability, light conditions, and carbon allocation trade-offs shape symbiotic performance across the five Mediterranean-type regions of the world (California, central Chile, the Cape Region of South Africa, southwestern Australia, and the Mediterranean Basin). By integrating physiological, ecological, and biogeochemical perspectives, we highlight how the shared features of these regions—strong seasonal drought, chronic nutrient limitation (particularly P in southwestern Australia and the Cape Region), recurrent fires, and exceptionally high plant diversity—constrain and, at the same time, favor the ecological success of symbiotic legumes. Throughout the review, we use case studies from key legume genera such as Lupinus in Chile and southwestern Australia, Virgilia and other Cape legumes in South Africa, Acacia in Australian kwongan and woodlands, and Medicago and Cytisus in the Mediterranean Basin and California to illustrate how general principles of legume–Rhizobium ecology manifest under Mediterranean-type climatic and edaphic constraints. Beyond summarizing established mechanisms, we critically examine the limitations of current metagenomic approaches, which often provide descriptive inventories of soil microbial communities without linking microbial composition to functional outcomes. We argue that advancing the field requires integrated, hypothesis-driven research that combines multi-omic tools with plant eco-physiology, soil nutrient dynamics, and temporal replication. Finally, we outline key priorities for future research, including the integration of functional ‘omics’, the study of microbiome interactions beyond rhizobia, the development of predictive models for Mediterranean-type ecosystems under climate change, and the application of symbiotic principles to restoration and agroecological management. By bridging molecular, physiological, and ecosystem perspectives, this review provides a conceptual framework for understanding and enhancing legume–Rhizobium symbiosis across five continents in a rapidly changing world. Full article

Aging is a progressive and heterogeneous biological process influenced by multiple factors that may compromise physical and cognitive capacities and increase the risk of frailty, functional decline, and falls in older adults. Falls represent a major public health concern due to their impact on independence and long-term care demand. Immersive virtual reality (IVR) delivered through active video games (exergames) has emerged as a preventive strategy that integrates sensory, motor, and cognitive stimulation within controlled and engaging environments, particularly where traditional programs face challenges related to adherence and individual adaptation. This study aims to determine the feasibility and implementation of an IVR-based program for falls prevention in older adults at risk of frailty in primary health care (PHC). A quasi-experimental pre–post design will be conducted with an intervention group (IVR/exergames) and a conventional control group, including a total sample of 40 participants (20 per group). The protocol comprises three phases: baseline assessment and IVR familiarization; a 12-week intervention delivered twice weekly; and post-intervention assessment. The primary outcome will be fall risk assessed using the Timed Up and Go (TUG) test. Secondary outcomes include physical performance (Short Physical Performance Battery, SPPB, and handgrip dynamometry) and psychological aspects related to falls (Falls Efficacy Scale International, FES-I, and Activities-specific Balance Confidence Scale, ABC). Feasibility indicators will include recruitment, adherence, retention, and cybersickness. A reduction in TUG time is expected, providing preliminary evidence on the feasibility of integrating IVR-based programs for falls prevention within PHC systems. Full article

Understanding the reproductive physiology of marine fish is critical for sustainable fisheries management, particularly under environmental variability. This study evaluated seasonal changes in body parameters (condition factor, Kn, and gonadosomatic index, GSI, as proxies for body condition and reproductive status, respectively) and biochemical composition (P, proteins; G, glucose; L, lipids; fatty acids; and bioenergetic ratios L/P, LG, all as proxy of integrated biochemical condition) of female gonads in Strangomera bentincki, a key pelagic species in the Humboldt Current System (HCS) off south-central Chile. Moreover, environmental factors (sea surface temperature and chlorophyll-a) were also analyzed to explore their influence on the FA profile of gonads. Female body parameters showed significant seasonal variations, with high values of Kn and GSI in autumn and spring, respectively. The biochemical composition also revealed significant seasonal variation in protein and glucose content, with the highest protein levels in winter and elevated glucose in autumn. While total lipid and energy content remained relatively stable across seasons, the L/P and L/G ratios presented seasonal variations. Similarly, the fatty acid composition showed pronounced seasonal differences, particularly with increased polyunsaturated fatty acids (e.g., DHA) in winter. The SST was the environmental factor with the greatest influence on the seasonal variations in the gonadal FA profile. Altogether, these findings suggest a partial capital breeding strategy in S. bentincki, where reproductive investment depends on both accumulated reserves and environmental conditions during reproduction. This study underscores the importance of incorporating reproductive biochemical indicators into ecosystem-based fisheries management models to improve assessments of stock health and reproductive potential. Full article

A system of initial teacher education must incorporate instruments capable of capturing the complexity of professional learning. In this context, national diagnostic assessments have become central mechanisms for monitoring outcomes in initial teacher education. This study examines student performance in Initial Teacher Education in Physical Education (ITEPE) programs using the themes assessed by the National Diagnostic Assessment (NDA) 2024, comparing achievement levels and analyzing differences according to the type of higher education institution in Chile. A quantitative, cross-sectional, and comparative design was employed, using official data from 1102 students enrolled in all Chilean universities offering the program. Descriptive and nonparametric inferential analyses were conducted to examine differences by sex and type of institution. The results show relatively homogeneous performance across standards, with higher percentages of achievement in dimensions related to didactic organization and assessment, and lower results in the standard associated with understanding student characteristics. Although statistically significant differences were identified according to administrative dependency, the effect sizes were small. Consequently, the NDA is positioned as a formative input to guide contextualized curricular improvements rather than as a mechanism for institutional ranking. Full article

Deploying artificial intelligence models on low-cost edge devices requires balancing predictive accuracy with strict constraints on computational resources, such as inference latency and memory footprint. Despite growing interest in TinyML systems, limited empirical evidence exists on how these factors interact across different embedded hardware platforms. This study presents a systematic multi-objective evaluation of three lightweight AI architectures—multinomial logistic regression (MLR), multilayer perceptron (MLP), and a reduced convolutional neural network (CNN)—implemented natively on three representative platforms: ESP32-S3, Raspberry Pi Pico, and Raspberry Pi Zero W. The models were evaluated on three image classification datasets of increasing complexity (Synthetic Geometric Figures, MNIST, and Fashion-MNIST), measuring classification accuracy, inference latency, and peak memory footprint under real execution conditions. Pareto-front analysis was used to identify efficient model–platform configurations and characterize the trade-offs between predictive performance and computational resources. The results provide quantitative insight into accuracy–resource trade-offs and establish a reproducible framework for evaluating lightweight AI models on resource-constrained edge devices, supporting informed design decisions in TinyML applications. Full article

The Juncal Norte Glacier (33°00′ S, 70°06′ W) is in the Dry Andes of central Chile within the Juncal Basin, a headwater watershed of the Aconcagua River, a semi-arid region experiencing an ongoing megadrought since 2010 and a 37% reduction in streamflow relative to pre-1990 baselines. This study provides the first glacier-specific annual melt and runoff estimate for Juncal Norte during mature megadrought conditions. Mass balance was estimated using a temperature index (positive degree day, PDD) model calibrated with automatic weather station (AWS) air temperature data and glacier hypsometry, assuming limited snow accumulation given that 2018–2019 precipitation and snow water equivalent (SWE) were extremely low relative to the long-term mean. Basin runoff was evaluated using a closure method comparing proglacial sub-basin-integrated discharge with modeled glacier melt volumes. Modeled glacier melt for 2018–2019 was equivalent to approximately 30% of observed annual discharge at the proglacial sub-basin, a disproportionate contribution given the glacier covers only 2.7% of the total basin area. The lower ablation zone (2900–4000 m), comprising 30% of glacier area, produced 90% of total melt volume. A + 1 °C temperature perturbation increased glacier-wide melt by 21.4%, confirming high climatic sensitivity. These results underscore the glacier’s critical but increasingly vulnerable buffering role for downstream water availability in the Dry Andes. Full article

Antimicrobial resistance is an emerging challenge in veterinary medicine, particularly in dogs, where bacterial skin infections are highly prevalent. Honey and its bioactive extracts have emerged as potential natural alternatives to conventional antimicrobials. This study evaluated the antimicrobial activity of methanolic extracts from four honey types collected in Central Chile against multidrug-resistant (MDR) bacterial isolates from canine patients, including Enterococcus faecium, Staphylococcus aureus, Escherichia coli, Pseudomonas aeruginosa, Pasteurella multocida, and Enterobacter cloacae. Antimicrobial potency was assessed by minimum inhibitory concentration (MIC), and phenolics, flavonoids, and antioxidant capacity were quantified. All extracts inhibited bacterial growth, with E. coli, E. faecium and S. aureus being the most susceptible (MIC 3.13% w/v), while Gram-negative bacteria such a P. aeruginosa, P. multocida, and E. cloacae required higher concentrations (MIC 12.5% w/v). Secondary metabolite analysis revealed seasonal and apiary-related variations, with apiary 2 honey showing significantly higher phenolic (195.58 ± 4.28 mg GAE/100 g) and flavonoid (65.46 ± 4.35 mg QE/100 g) contents in summer. In contrast, antioxidant capacity (FRAP) did not differ significantly. These findings indicate that honey’s antimicrobial properties are closely related to its bioactive composition and influenced by season and floral origin, reinforcing its potential as a sustainable alternative to antibiotics in veterinary medicine under the One Health approach. Full article

Food by-products have gained importance as valuable sources of bioactive compounds and structural lipids, with potential applications in food packaging. These residues, such as fruit peels, seeds, and fish skin, contain polymers and natural compounds like polyphenols, carotenoids, tocopherols, and phospholipids, which possess antioxidant and antimicrobial properties highly relevant for food preservation. However, the direct incorporation of these compounds is limited by their sensitivity to environmental factors such as light, oxygen, and pH. Liposomal encapsulation has emerged as a promising strategy to overcome these challenges, providing protection, controlled release, and increased bioavailability of both hydrophilic and lipophilic bioactives. The formulation of liposomes using lipids recovered from food industry by-products introduces an additional sustainability component, in line with the principles of the circular economy. Combining liposomes with other advanced preservation technologies, such as edible coatings and films, electrospinning fibers, and cyclodextrin inclusion complexes, is a promising alternative for extending the shelf-life and safety of food products, as well as for the development of functional foods. This review discusses the latest advances in liposome formulations with food by-products and their combination with other technologies to enhance their effectiveness in food preservation. Full article

The rapid digital transformation of education systems has profoundly changed teachers’ working conditions, intensified administrative demands, and highlighted territorial and organizational inequalities. In this context, understanding how these dynamics influence teacher engagement is essential for promoting healthy educational organizations. This study examined the factor structure of the UWES-17 and analyzed the relationship between engagement levels and sociodemographic variables in a sample of 314 elementary school teachers from four regions of Chile. Descriptive analyses, exploratory factor analysis with polychoric correlations and unweighted least squares, and confirmatory factor analysis using robust ULS and the Hull method were performed. The results showed a robust two-factor structure—Inspired Vitality and Challenging Commitment—with excellent fit indices. Freeman–Halton exact tests showed that Inspired Vitality was significantly associated with age, gender, region, location, administrative dependency, and professional experience, while Challenging Commitment was associated with gender, region, context, and professional experience. These findings indicate that teacher engagement is influenced by both structural inequalities and individual trajectories. The results underscore the need to strengthen organizational resources, regulate digital intensification, and reduce territorial gaps to promote teacher well-being. Full article

Behaviour management represents a complex dimension of the teaching profession, especially in contexts of high social vulnerability. This instrumental case study qualitatively analysed the experiences of four teachers from a technical–professional high school in Santiago, Chile, focusing on how they construct and sustain behaviour management in everyday classroom work. Data were generated through semi-structured interviews and analysed using qualitative content analysis. Findings foreground a central tension in which reactive management predominates over preventive strategies, shaping how teachers sustain pedagogical continuity under recurrent disruption. Teachers describe this work as a reflective construction negotiated between routines and adaptation to contingencies, supported by bonds of trust with students and informal peer collaboration within an institutional structure perceived as fragmented. These insights can inform teacher education by strengthening practice-oriented preparation for behaviour management and can support the refinement of educational coexistence policies in context-sensitive ways. Full article

Chagas disease, caused by Trypanosoma cruzi, is maintained in nature by complex interactions among wild vertebrates and triatomine insect vectors, yet the role of many introduced hosts remains poorly resolved. Here, we assessed natural T. cruzi infection in wild European rabbits (Oryctolagus cuniculus) from central Chile, where introduced rabbits overlap ecologically with the sylvatic vector Mepraia spinolai. Eight free-ranging rabbits captured in Las Chinchillas National Reserve were evaluated using an integrative diagnostic approach combining xenodiagnosis with laboratory-reared, parasite-free M. spinolai nymphs, real-time polymerase chain reaction targeting T. cruzi satellite DNA in blood and 12–14 organs per animal, and histopathology with immunohistochemistry (anti-cruzipain) to identify tissue parasite forms. Blood molecular detection was positive in seven out of eight rabbits, while xenodiagnosis detected viable parasites in two out of seven evaluated individuals. Organ molecular screening detected T. cruzi DNA in at least one organ in all rabbits, with frequent positivity in the diaphragm, reproductive tissues, spleen, and kidney. Histopathology identified parasite forms in four out of eight animals, and immunohistochemistry confirmed hepatic amastigotes in one case. These findings provide multi-method evidence of natural infection in the sampled individuals, including evidence of parasite viability in some individuals, suggesting potential epidemiological relevance within this ecological context and possible utility for surveillance in Chilean sylvatic transmission settings. Full article

In this work, we investigate the shadow properties of the Kerr–Newman–Anti-de Sitter black hole coupled to nonlinear electrodynamics. The shadow is constructed by employing the celestial coordinate approach for an observer located at a finite distance, which is required due to the non-asymptotically flat structure of the spacetime. The size, distortion, area, and oblateness of the shadow are analyzed in terms of the black hole parameters, namely, the spin, the effective charge, and the nonlinearity parameter. We show that the nonlinear electrodynamics significantly modifies the photon region and therefore changes the shadow observables, while the rotation mainly controls the deformation of the silhouette. We further confront the theoretical results with the Event Horizon Telescope observations of M87* and Sgr A* in order to constrain the parameter space of the model. The allowed ranges of the effective charge depend sensitively on the nonlinearity parameter, and the combination of both sources leads to tighter and physically more consistent bounds. In addition, we study the energy emission rate derived from the shadow radius and the Hawking temperature and discuss how it is affected by the rotation and the nonlinear electromagnetic field. Our analysis shows that the considered black hole solution provides a consistent extension of the Kerr geometry in a non-asymptotically flat background and that the shadow observables can be used as an efficient tool to test the effects of nonlinear electrodynamics in strong gravity. Full article

Industrial coastal basins that host heavy industry can concentrate metal-bearing dust in school environments. We performed a screening multi-matrix assessment across six schools in Quintero–Puchuncaví (central Chile). We measured As, Cd, Cr, Cu, Ni, Pb, and Mn in surface soils (winter 2023; E1–E4 only), indoor settled dust, and settleable particulate matter (SPM) collected in winter (July 2023) and summer (November 2023). Concentrations were determined by ICP-OES/ICP-MS and interpreted with enrichment factors and the geoaccumulation index. A U.S. EPA screening framework was used to estimate non-carcinogenic hazard (HQ) and incremental lifetime cancer risk (ILCR) for ingestion, inhalation, and dermal contact, as well as cumulative indices for non-carcinogenic (HI) and carcinogenic risk (Risk). SPM carried the strongest anthropogenic signal (EF up to 9900 for Cd, 408 for Cu, and 143 for Pb) and the highest summer loads (Cu > 5000 mg kg⁻¹; Ni > 1000 mg kg⁻¹). Cu dominated non-carcinogenic hazard (HQ up to 137), whereas ILCR was driven by Ni, As, and Cr, exceeding 10⁻⁴ and reaching 10⁻³ at inland/valley schools in summer. Indoor dust showed intermediate burdens, indicating indoor accumulation of outdoor-derived metals, while the winter soil survey provides a baseline indication of outdoor metal reservoirs at the sampled schools. Despite the limited sample size, the results provide screening-level evidence to inform emission control and dust mitigation in school microenvironments. Full article

Climate change poses increasing challenges to agricultural systems in vulnerable territories, where climate variability, ecosystem degradation, and governance constraints interact to shape farmers’ management decisions. Understanding how institutional and social factors influence adaptive responses is therefore critical. This study examines how trust in public environmental agencies shapes small farmers’ willingness to adopt climate change adaptation practices in the highly vulnerable district of Alhué, central Chile. A structured questionnaire was administered to small farmers to assess willingness to adopt adaptive practices and levels of trust in public environmental agencies. Multivariate models revealed a non-linear, U-shaped relationship between trust in agencies and willingness to adopt adaptive practices: willingness was lowest at intermediate levels of trust and higher among farmers reporting either low or high trust in environmental agencies. This pattern remains robust after controlling for socioeconomic characteristics and climate change perceptions. The results highlight how heterogeneous trust dynamics condition adaptive behavior, suggesting that both barriers and strong institutional confidence may influence adaptation through different mechanisms. Overall, the findings underscore the importance of socially legitimate and context-sensitive governance arrangements for fostering climate change adaptation in vulnerable rural territories. Full article