Universidad Austral de Chile
  • Valdivia, Región de Los Ríos, Chile
Recent publications
Forest restoration aims to increase forest cover, structure, function, and/or species composition, and it influences hydrology through the partitioning of precipitation into evapotranspiration and streamflow. This paper provides a conceptual framework for forest restoration and hydrology, reviews the literature on forest hydrology that is relevant to forest restoration, and assesses practical forest restoration approaches, their hydrologic effects, and tradeoffs. The hydrologic effects of three types of forest are assessed: mature and old-growth forests, which often are the reference model for restoration; managed forest plantations, which dominated early efforts for forest restoration; and the early stages of native forest succession, an increasingly popular, ecologically-oriented or nature-based approach to forest restoration. This review indicates that mature and old-growth forests have high evapotranspiration and consistent water yield, provided by moderated peak discharges and sustained low flows, while water yield is low from managed forest plantations, especially during dry periods. The early stages of native forest succession may provide greater water yield and increased low flows compared with managed plantations. Inclusion of native species and natural processes in forest restoration can increase some hydrological benefits relative to other forest restoration approaches. Although forest restoration affects hydrology, few studies examine the hydrologic effects of specific forest restoration practices such as choice of species, silvicultural practices, legacies of past land use, and geographic setting. Forest managers and ecologists can play valuable roles by designing studies that explore the hydrologic effects of forest restoration approaches on time scales relevant to ecological succession and forest management under a changing climate.
Objective: The aim of this study was to compare academic achievement, cognitive performance, playtime, bullying, and discrimination in adolescents according to traditional uniforms (TUs) and sports uniforms (SUs) worn at school, while simultaneously exploring the influence of the school vulnerability index. Methods: A total of 988 Chilean adolescents (52.6% boys) aged 10–14 years participated in this cross-sectional study. Academic achievement was evaluated by the average grade in maths, language, and science grades, while cognitive performance was assessed through eight cognitive tasks. TUs affecting physical activity, playtime, bullying, and discrimination were queried. Mixed model analyses were performed. Results: No differences were observed in academic achievement (TU: 5.4 ± 0.1 vs. SU: 5.5 ± 0.2, p = 0.785) or in cognitive performance (TU: 99.6 ± 0.8 vs. SU: 98.9 ± 1.8, p = 0.754) according to the school uniform type. Moreover, 64.1% of participants declared that wearing TU affects their physical activity (traditional uniforms: +8min and sports uniforms: +20min), and those who believed so spent more time playing than those who answered negatively (14.5 min, p = 0.012). Finally, adolescents wearing SU displayed a lower feeling of bullying and discrimination; this finding depended mainly on the school’s vulnerability. Conclusion: It is concluded that wearing TU does not show an educational advantage at an academic and cognitive level that justifies its obligation. In addition, it could be suggested that schools consider adolescents’ opinions in adopting a more comfortable uniform, such as the SU. This feasible and low-cost measure would help to increase adolescents’ physical activity during the school day, and, contrary to belief, it would not be related to increased feelings of bullying and discrimination.
The protozoan parasite Eimeria bovis is the causative agent of bovine coccidiosis, an enteric disease of global importance that significantly affects cattle productivity. Previous studies showed that bovine NETosis—an important early host innate effector mechanism of polymorphonuclear neutrophil (PMN)—is elicited by E. bovis stages. So far, the metabolic requirements of E. bovis -triggered NET formation are unknown. We here studied early glycolytic and mitochondrial responses of PMN as well as the role of pH, distinct metabolic pathways, P2 receptor-mediated purinergic signaling, and monocarboxylate transporters 1 and 2 (MCT1, MCT2) in E. bovis sporozoite-induced NET formation. Seahorse-based experiments revealed a rapid induction of both neutrophil oxygen consumption rate (OCR) and early glycolytic responses, thereby reflecting immediate PMN activation and metabolic changes upon confrontation with sporozoites. The impact of these metabolic changes on NET formation was studied via chemical inhibition experiments targeting glycolysis and energy generation by the use of 2-fluor-2-deoxy-D-glucose (FDG), 6-diazo-5-oxo-L-norleucin (DON), sodium dichloroacetate (DCA), oxythiamine (OT), sodium oxamate (OXA), and oligomycin A (OmA) to block glycolysis, glutaminolysis, pyruvate dehydrogenase kinase, pyruvate dehydrogenase, lactate dehydrogenase, and mitochondrial ATP-synthase, respectively. Overall, sporozoite-induced NET formation was significantly diminished via PMN pretreatments with OmA and OXA, thereby indicating a key role of ATP- and lactate-mediated metabolic pathways. Consequently, we additionally studied the effects of extracellular pH, MCT1, MCT2, and purinergic receptor inhibitors (AR-C141900, AR-C155858, theobromine, and NF449, respectively). Pretreatment with the latter inhibitors led to blockage of sporozoite-triggered DNA release from exposed bovine PMN. This report provides first evidence on the pivotal role of carbohydrate-related metabolic pathways and purinergic receptors being involved in E. bovis sporozoite-induced NETosis.
Many coral reef fishes display remarkable genetic and phenotypic variation across their geographic ranges. Understanding how historical and contemporary processes have shaped these patterns remains a focal question in evolutionary biology, since they reveal how diversity is generated and how it may respond to future environmental change. Here we compare the population genomics and demographic histories of a commercially and ecologically important coral reef fish, the common coral grouper (Plectropomus leopardus [Lacépède 1802]), across two adjoining regions (the Great Barrier Reef; GBR, and the Coral Sea, Australia) spanning approximately 14 degrees of latitude and 9 degrees of longitude. We analysed 4,548 single nucleotide polymorphism (SNP) markers across 11 sites and show that genetic connectivity between regions is low, despite their relative proximity (~ 100 km) and an absence of any obvious geographic barrier. Inferred demographic histories using 10,479 markers suggest that the Coral Sea population was founded by a small number of GBR individuals and that divergence occurred ~ 190 kya under a model of isolation with asymmetric migration. We detected population expansions in both regions, but estimates of contemporary effective population sizes were approximately 50 % smaller in Coral Sea sites, which also had lower genetic diversity. Our results suggest that P. leopardus in the Coral Sea have experienced a long period of isolation that precedes the recent glacial period (~ 10 – 120 kya) and may be vulnerable to localised disturbances due to their relative reliance on local larval replenishment. While it is difficult to determine the underlying events that led to the divergence of Coral Sea and GBR lineages, we show that even geographically proximate populations of a widely dispersed coral reef fish can have vastly different evolutionary histories.
A partir de la revuelta social chilena que inicia el 18 de octubre del 2019 emergen grupos y movimientos que luchan por el reconocimiento de la dignidad arrebatada; uno de ellos lo componen las personas con discapacidad, un colectivo históricamente catalogado como despolitizado; y otro, la Primera Línea, neologismo de un grupo anónimo deslegitimado por enfrentarse a las fuerzas policiales, cuyo objetivo sería el de proteger las manifestaciones ciudadanas. Ambas colectividades son invisibilizadas y carecen de reconocimiento en el orden social, calificadas como inhabilitados unos y violentos los otros, excluidos de la protesta organizada y de las demandas transversales que gatillan la revuelta. En el presente artículo observaremos el actuar de estas dos colectividades y las diferentes formas de manifestación durante la revuelta popular chilena, a la luz de los aportes teóricos que Nancy Fraser y Judith Butler han hecho a las teorías del reconocimiento. Buscamos transitar desde el menosprecio y la exclusión a la cual estos grupos han sido sometidos, hacia la utopía de reconocimiento por la vía normativa del proceso constitucional en curso.
The special features displayed by family firms characterize and shape their family social capital and make them unique. The participation of both the family and the firm creates distinctive resources and capabilities in the family firm. As new generations arrive, opposing forces begin to shake the firm, and while some embrace change others expect the continuity of the family influence. Likewise, the influence of the family in the firm conditions its performance. In this study, we empirically address how family influence promotes the development of family social capital that, in turn, impacts on the organizational effectiveness of family firms. Furthermore, we observe the moderating role of generational involvement by considering generations an important source of heterogeneity in family firms. We test the hypotheses on a sample of Spanish family firms, analyzing the data using partial least squares (PLS). Results indicate that the family influence positively affects the development of family social capital and, therefore, the organizational effectiveness of the family firm. However, generational involvement can moderate both relationships in a negative way, by reducing the development and exploitation of the family social capital.
For the inflaton field, we determine a new exact solution by using the Lie symmetry analysis. Specifically, we construct a second-order differential master equation for arbitrary scalar field potential by assuming that the spectral indices for the density perturbations [Formula: see text] and the scalar-to-tensor ratio [Formula: see text] are related as [Formula: see text]. Function [Formula: see text] is classified according to the admitted Lie symmetries for the master equation. The possible admitted Lie symmetries form the [Formula: see text], [Formula: see text], [Formula: see text] and [Formula: see text] Lie algebras. The new inflationary solution is recovered by the Lie symmetries of the [Formula: see text] algebra. Scalar field potential is derived explicitly, while we compare the resulting spectral indices with the observations.
At first glance, it seems that modern, inexpensive additive manufacturing (AM) technologies can be used to produce innovative, efficient acoustic materials with tailored pore morphology. However, on closer inspection, it becomes rather obvious that for now this is only possible for specific solutions, such as relatively thin, but narrow-band sound absorbers. This is mainly due to the relatively poor resolutions available in low-cost AM technologies and devices, which prevents the 3D-printing of pore networks with characteristic dimensions comparable to those found in conventional broadband sound-absorbing materials. Other drawbacks relate to a number of imperfections associated with AM technologies, including porosity or rather microporosity inherent in some of them. This paper shows how the limitations mentioned above can be alleviated by 3D-printing double-porosity structures, where the main pore network can be designed and optimised, while the properties of the intentionally microporous skeleton provide the desired permeability contrast, leading to additional broadband sound energy dissipation due to pressure diffusion. The beneficial effect of additively manufactured double porosity and the phenomena associated with it are rigorously demonstrated and validated in this work, both experimentally and through precise multiscale modelling, on a comprehensive example that can serve as benchmark.
Genome size (GS) or DNA nuclear content is considered a useful index for making inferences about evolutionary models and life history in animals, including taxonomic, biogeographical, and ecological scenarios. However, patterns of GS variation and their causes in crustaceans are still poorly understood. This study aimed to describe the GS of five Neotropical Synalpheus nongambarelloides shrimps (S. apioceros, S. minus, S. brevicarpus, S. fritzmueller, and S. scaphoceris) and compare the C-values of all Caridea Infraorder in terms of geography and phylogenetics. All animals were sampled in the coast of São Paulo State, Brazil and GS was assessed by flow cytometry analysis (FCA). The C-values ranged from 7.89 pg in S. apioceros to 12.24 pg in S. scaphoceris. Caridean shrimps had higher GS than other Decapoda crustaceans. The results reveal a tendency of obtaining larger genomes in species with direct development in Synalpheus shrimps. In addition, a tendency of positive biogeographical (latitudinal) correlation with Caridea Infraorder was also observed. This study provides remarkable and new protocol for FCA (using gating strategy for the analysis), which led to the discovery of new information regarding GS of caridean shrimps, especially for Neotropical Synalpheus, which represents the second-largest group in the Caridea Infraorder.
The growing worry about changing climatic circumstances, the COVID-19 economic crisis, and the management and conservation of biological resources necessitates the development of appropriate models for the long-term management of mining resources, as well as the regulation of extractivism at the Latin American level and its massive effects on the environment and communities. The major goal of this paper is to evaluate the influence of the mining conflict on the scholar. This study analyzed the Latin American mining sector and its recent evolution in the socio-ecological conflicts issues. The research was conducted through a bibliometric analysis in Scopus database from 1991 to 2020. The period with the highest concentration of publications was from 2013 to 2020, and the countries with the most substantial number of publications are Colombia and the USA. Our article concludes that mining conflicts are causing increasing worry among scholar, and their management has significant potential to address the issues of protecting the environment and communities while avoiding the crisis and its consequences in Latin America.
Air pollution in coastal cities and nearby communities has become a health problem in the last decades because of the dispersion of pollutants produced by the various port activities. In this context, when a vessel at berth uses its auxiliary engines to generate the electric power to maintain its service, the operational profile is not continuous; the auxiliary engines work outside their fuel efficiency range, producing additional pollutant emissions. To reduce emissions while in port and at berth, two short-term options are considered: the first option is using alternative energy sources such as liquefied natural gas (LNG) instead of current fuels. The second option is using cold ironing technology, which enables to turn-off the vessels auxiliary engines, by feeding the services using shore power supply. In a classical cold ironing configuration, energy only flows from shore to on board. This work presents an emissions assessment of a tanker vessel at berth, applying a novel bi-directional energy flow strategy associated to a cold ironing system, integrating LNG, and compared to current fuels used, focused on the environmental impact on Quintero’s Bay. This bay is one of the most important port areas of the Chilean coast deemed to be affected by emissions generated by intense port activities. Taking current fuels such as heavy fuel oil (HFO) and marine diesel oil (MDO) and ship’s arrivals/departures from port as a reference case, the results presented in this work, show a significant reduction in emissions when applying the bi-directional energy flow strategy.
We study the temporal equation of radiating stars by using three powerful methods for the analysis of nonlinear differential equations. Specifically, we investigate the global dynamics for the given master ordinary differential equation to understand the evolution of solutions for various initial conditions as also to investigate the existence of asymptotic solutions. Moreover, with the application of Lie's theory, we can reduce the order of the master differential equation, while an exact similarity solution is determined. Finally, the master equation possesses the Painlevé property, which means that the analytic solution can be expressed in terms of a Laurent expansion.
The purpose of this study was to test the hypothesis that the genetic diversity of commercially significant species of King Crabs (Lithodes spp.) along the south‐eastern Pacific (SEP) comprises different independent evolutionary units (IEUs) with spatially isolated distribution. Nine localities from inner and open waters along the SEP Chilean coast (39°S‐55°S) were sampled. We analyzed sequences from 173 individuals for the mitochondrial gene Cytochrome oxidase I (COX‐I), 151 individuals for the Internal Transcribed Spacer 1 (ITS) and 135 for the structural ribosomal RNA (28S). Genetic delimitation was performed through three analytical methods: ABGD, GMYC, and its Bayesian implementation, bGMYC. Bayesian phylogenetic analyses and haplotype networks were also performed. Divergence time between clades was assessed for the COX‐I marker and estimated from known evolutionary rates for this marker in other crustacean species and fossil calibration from other Anomuran species. Delimitation analyses, phylogenetic analyses, and mitochondrial haplotype networks suggested the presence of two deeply divergent mitochondrial lineages of Lithodes in the SEP, referred to as Clade1 and Clade 2. Nuclear markers showed low phylogenetic resolution and therefore were unsuitable for molecular species delimitation. Divergence time analysis of the mitochondrial lineages suggests a separation between Clades of approximately 2.3 Mya. The divergence time obtained suggested that Pliocene glaciations and deglaciations cycles could be involved in hybridization events between Lithodes IEUs at southern tip of South American coasts. The different frequencies of Lithodes haplotypes in inner and open water environments along SEP coasts could be explained by events such as the last glacial maximum or by differences in the adaptation of each clade to different environments. These findings support the necessity of evaluating the taxonomic status of Lithodes individuals found along SEP coasts under an integrative taxonomy approach or through markers with other evolution rates than those already used. The purpose of this study was to assess the biodiversity of individual Lithodes spp. across the Southerneast Pacific with multilocus molecular markers. A complex of independent evolutionary units comprising at least two genetically distinct lineages with different spatial distribution is observed.
Punta Pelluco is a known fossil forest locality near Puerto Montt in the province of Llanquihue, Southern Chile, which preserves exquisite palynological and xylological records of the last glacial period (Late Pleistocene), discoveries that have been made since 1978. The present investigation contributes the first Chilean record of camelid and proboscidean footprints, discovered in 2015 at Punta Pelluco. The ichnospecies identified are Lamaichnum guanicoe (average footprint 10.1 cm length, 9.9 cm width) and the largest Proboscipeda cf. P. australis (average 38 cm length, 38.2 cm width in the first footprint and average 41.8 cm length, 42.2 cm width in the second footprint) found in South America, respectively. These are the oldest Chilean records for Lamini and Proboscidea, dating back to between about 52.300 and 44.400 years ago. Not much is known about the dispersal of camelids and gomphotherids through the Andean Mountains after the Great American Biotic Interchange, but the present record status seems to indicate that the presence was restricted to the Pleistocene, at least 45,000 years ago.
Eocene early‐diverging representatives of South American extinct notungulates are traditionally considered to have been ‘generalists’ and ‘non‐specialized’ in terms of appendicular skeleton and locomotor behavior, as is the case with the notostylopid Notostylops, a middle Eocene iconic taxon from Patagonia (Argentina). However, they are mainly known from dental remains, and associated cranial and postcranial elements are scarce. The discovery of a nearly complete specimen attributed to N. murinus allows us to: 1) increase the knowledge of the anatomy of its appendicular skeleton; 2) identify isolated bones from several collections and suggest different taxonomic interpretations for published specimens; 3) perform a biomechanical and functional study using functional morphological analysis to infer its paleoecological attributes (e.g. posture, locomotor habit, estimated speed and body mass); and 4) establish morphofunctional comparisons, based on possible functional ranges, with other extinct early‐diverging notoungulates from the middle Eocene, such as the Notopithecid Notopithecus. Our evidence suggests that Notostylops was a medium‐sized mammal (8.5 – 20 kg), which could achieve a dynamic digitigrade posture that allowed a scansorial secondary locomotor habit and a speed of up to 50 km/h. While Notopithecus was a small‐sized mammal (0.6 –1.4 kg) with a plantigrade posture both in a static and dynamic context, terrestrial habits and speed of up to 35 km/h. Therefore, we conclude that these Eocene notoungulates show different locomotor capabilities, which can be associated to early niche diversifications, clearly contrasting with the ‘all‐generalists’ paradigmatic view. This article is protected by copyright. All rights reserved.
Collecting entomopathogenic fungi associated with mosquitoes and studies on their activity against mosquito developmental stages will improve the understanding of their potential as agents to control important mosquito vectors. Twenty one strains of entomopathogenic fungi affecting mosquitoes in Central Brazil were studied: 7 of Beauveria bassiana, 7 of Metarhizium humberi, 3 of M. anisopliae, 2 of Cordyceps sp. and one each of Akanthomyces saksenae and Simplicillium lamellicola. These fungi were isolated from field-collected mosquito adults (3 strains) or larvae (a single strain); the other 17 strains were isolated from laboratory-reared Aedes aegypti sentinel larvae set out in partially immersed cages placed in diverse small- to middle-sized aquatic mosquito habitats in or close to areas with secondary tropical forest. The frequent recovery of normally soil-borne Metarhizium spp. and B. bassiana from aquatic habitats is notable. Our laboratory findings indicated that M. anisopliae IP 429 and IP 438 and M. humberi IP 421 and IP 478 were highly active against immature stages and, together with M. anisopliae IP 432, also against adults. These strains appear to be the most promising candidates to develop effective control strategies targeting the different developmental stages of A. aegypti, the most important vector of viral diseases in humans in the tropics.
The conversion of native forest to forestry plantations is a worldwide practice, affecting biodiversity and host-parasite interactions. One of the most common timber plantations in the world are monocultures of Monterey pine (Pinus radiata). Using occupancy models, we analyzed the occurrence and prevalence of Cryptosporidium spp. oocysts and Giardia spp. cysts in fecal samples of wild rodents from a landscape dominated by extensive Monterey pine plantations in central Chile. We aimed to assess drivers of parasite infection such as habitat type, abundance of rodent hosts, species richness, and season. Small mammals were sampled seasonally for two years in three habitat types: native forests, adult pine plantations and young pine plantations. A total of 1091 fecal samples from seven small mammal species were analyzed by coprological analysis. Occurrence probability of Cryptosporidium spp. and Giardia spp. was similar for the most abundant rodent species (Abrothrix longipilis, A. olivacea, and Oligoryzomys longicaudatus) and for all habitat types. For Cryptosporidium spp., variation in prevalence was mostly explained by season with higher prevalence during winter season and lower during spring. For Giardia spp., the prevalence was significantly higher in young pine plantations, followed by adult pine plantations and native forests. In addition, higher prevalence of Giardia spp. was associated with lower host richness, suggesting a possible dilution effect. Our findings reveal that Monterey pine plantations increase Giardia spp. transmission among rodents, but has no clear effect on Cryptosporidium spp., providing evidence that the impact of land use on parasitism can be idiosyncratic. Since both parasites have zoonotic potential, our findings may be useful for land use planning and management considering health issues.
We establish an original result for the thermodynamic formalism in the context of expanding circle transformations with an indifferent fixed point. For an observable whose modulus of continuity is linked to the dynamics near such a fixed point, by identifying an appropriate linear space to evaluate the action of the transfer operator, we show that there is a strictly positive eigenfunction associated with the maximal eigenvalue given as the exponential of the topological pressure. Taking into account also the corresponding eigenmeasure, the invariant probability thus obtained is proved to be the unique Gibbs-equilibrium state of the system.
Headwaters represent an essential component of hydrological, ecological, and socioeconomical systems, by providing constant water streams to the complete basin. However, despite the high importance of headwaters, there is a lack of vulnerability assessments worldwide. Identifying headwaters and their vulnerability in a spatially explicit manner can enable restauration and conservation programs. In this study, we assess the vulnerability of headwaters in South-Central Chile (38.4 to 43.2°S) considering multiple degradation factors related to climate change and land cover change. We analyzed 2292 headwaters, characterizing multiple factors at five spatial scales by using remote sensing data related to Land Use and Cover Change (LUCC), human disturbances, vegetation cover, climate change, potential water demand, and physiography. We then generated an index of vulnerability by integrating all the analyzed variables, which allowed us to map the spatial distribution of headwater vulnerability. Finally, to estimate the main drivers of degradation, we performed a Principal Components Analysis with an Agglomerative Hierarchical Clustering, that allowed us to group headwaters according to the analyzed factors. The largest proportion of most vulnerable headwaters are located in the north of our study area with 48.1 %, 62.1 %, and 28.1 % of headwaters classified as highly vulnerable at 0, 10, and 30 m scale, respectively. The largest proportion of headwaters are affected by Climate Change (63.66 %) and LUCC (23.02 %) on average across all scales. However, we identified three clusters, in which the northern cluster is mainly affected by LUCC, while the Andean and Coastal clusters are mainly affected by climate change. Our results and methods present an informative picture of the current state of headwater vulnerability, identifying spatial patterns and drivers at multiple scales. We believe that the approach developed in this study could be useful for new studies in other zones of the world and can also promote Chilean headwater conservation.
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4,926 members
Isabel Margarita Aguirre Gil
  • Instituto de Patología Animal
Jorge Nimptsch
  • Instituto de Ciencias Marinas y Limnológicas UACh
Mauricio Barría
  • Faculty of Medicine
Jose Urdaneta
  • Instituto de Anatomía, Histología y Patología
Andrés Valenzuela Sánchez
  • Instituto de Conservación Biodiversidad y Territorio
Independencia 657, 5090000, Valdivia, Región de Los Ríos, Chile
Head of institution
Dr. Hans Richter, Rector