Universidad de Magallanes
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Adipokines at the Metabolic-Brain Interface: Therapeutic Modulation by Antidiabetic Agents and Natural Compounds in Alzheimer's Disease
No full textThe parallel global increase in obesity and Alzheimer's disease (AD) underscores an urgent public health challenge, with converging evidence indicating that metabolic dysfunction strongly contributes to neurodegeneration. Obesity is now recognized not only as a systemic metabolic condition but also as a modifiable risk factor for AD, acting through mechanisms such as chronic low-grade inflammation, insulin resistance, and adipose tissue dysfunction. Among the molecular mediators at this interface, adipokines have emerged as pivotal regulators linking metabolic imbalance to cognitive decline. Adipokines are hormone-like proteins secreted by adipose tissue, including adiponectin, leptin, and resistin, that regulate metabolism, inflammation and can influence brain function. Resistin, frequently elevated in obesity, promotes neuroinflammation, disrupts insulin signaling, and accelerates beta-amyloid (A beta) deposition and tau pathology. Conversely, adiponectin enhances insulin sensitivity, suppresses oxidative stress, and supports mitochondrial and endothelial function, thereby exerting neuroprotective actions. The imbalance between resistin and adiponectin may shift the central nervous system toward a pro-inflammatory and metabolically compromised state that predisposes to neurodegeneration. Beyond their mechanistic relevance, adipokines hold translational promise as biomarkers for early risk stratification and therapeutic monitoring. Importantly, natural compounds, including polyphenols, alkaloids, and terpenoids, have shown the capacity to modulate adipokine signaling, restore metabolic homeostasis, and attenuate AD-related pathology in preclinical models. This positions adipokines not only as pathogenic mediators but also as therapeutic targets at the intersection of diabetes, obesity, and dementia. By integrating mechanistic, clinical, and pharmacological evidence, this review emphasizes adipokine signaling as a novel axis for intervention and highlights natural compound-based strategies as emerging therapeutic approaches in obesity-associated AD. Beyond nutraceuticals, antidiabetic agents also modulate adipokines and AD-relevant pathways. GLP-1 receptor agonists, metformin, and thiazolidinediones tend to increase adiponectin and reduce inflammatory tone, while SGLT2 and DPP-4 inhibitors exert systemic anti-inflammatory and hemodynamic benefits with emerging but still limited cognitive evidence. Together, these drug classes offer mechanistically grounded strategies to target the adipokine-inflammation-metabolism axis in obesity-associated AD
The Magellanic Woodpecker's role in its assemblage: a case study of cavity provisioning and habitat selection in the world's southernmost forests
No full textWoodpeckers are adept cavity excavators and various species, i.e., secondary cavity-users (SCUs), may depend on these cavities. Birds use specific habitat attributes to increase their likelihood of survival, but these attributes vary among cavity users. We examine the role of cavity provisioning by Magellanic Woodpeckers (Campephilus magellanicus, MAWO, 275-347 g), the largest woodpeckers in South America. From 2015-2017 on Navarino Island, Chile (55 degrees 4' 0.12 '' S, 67 degrees 40' 1.2 '' W), we (1) assessed SCU densities and richness; (2) compared assemblage cavity use between MAWO-excavated and non-excavated cavities; and (3) determined which habitat attributes influence cavity use by MAWOs and the SCU assemblage. We found 12 SCU species ranging from similar to 11-447 g; Thorn-tailed Rayadito (Aphrastura spinicauda, similar to 12 g) was the most abundant (i.e., 9.24 individuals/ha) and frequent SCU that used non-excavated cavities. Magellanic Woodpeckers selected taller and larger-diameter Nothofagus trees to excavate their cavities, which were placed higher off the ground and had wider cavity entrances compared to those used by SCUs. Of the used cavities, MAWOs provided a small proportion to the SCU assemblage in general. Specifically, small passerines rarely used cavities provided by this large woodpecker, matching findings elsewhere globally. However, their cavity provisioning may be an important resource for larger birds, particularly raptors and parakeets. Moreover, MAWOs may play a key part in other ecological roles, e.g., by providing foraging and oviposition sites for birds and insects, respectively, or by vectoring wood-decay fungi. Additionally, we found evidence that SCUs use MAWO-enlarged foraging holes as nesting cavities; therefore, MAWOs may provide an ecological service for the broader SCU assemblage, but via a different mechanism than simply cavity excavation. We suggest researchers determine if MAWO-provided cavities increase SCU fitness or reproductive success. Further, we suggest researchers check cavities to determine if they are internally excavated and provide accurate information on cavity use, particularly if management and conservation decisions are made based upon these data
Gasification of Lenga (Nothofagus pumilio) chips in a fixed bed system for rural area implementation: Magallanes case study
No full textThis research explores the gasification of Lenga wood chips (Nothofagus pumilio) sourced from forest remnants within a fixed-bed gasification system with a 10 kWe capacity. The primary focus is on its potential application in remote rural regions. Utilizing a factorial analysis approach, we examine the influence of particle size (ranging from 3-8 mm to 8-20 mm) and the frequency of bed agitation (occurring every 2, 4, and 6 minutes) on critical performance indicators. Throughout the experimentation, the equivalence ratio (ER) remains constant within the range of 0.17-0.20. Cold efficiency demonstrates variability, spanning from 44.8% to 58.8%. Meanwhile, the High Heating Value (HHV) varies between 6.07 and 7.18 MJ/Nm3, with gasification temperatures fluctuating between 850 and 900 °C. The introduction of bed agitation, whether at high or low frequencies, has a notable impact on gas flow, leading to substantial deviations. Larger particle sizes tend to enhance gas flow and process stability but simultaneously have adverse effects on HHV, ER, and overall process efficiency. During transient analysis, it becomes evident that gas flow requires a prolonged duration to achieve stabilization. Frequent agitation cycles (at a rate of 1/140 s−1) result in fewer deviations but a slower stabilization process, whereas less frequent agitation (1/380 s−1) induces greater variations but accelerates the stabilization phase. This comprehensive investigation offers valuable insights into the optimization of Lenga wood chip gasification, particularly for addressing energy needs in rural areas by harnessing forest residues
Hybrid dynamic model of spur gears under combined misalignments
No full textThis research proposes a hybrid model for predicting the vibration behavior of a single-stage spur gear transmission system under various misalignment conditions. The model combines finite element analysis (FEA) to estimate the forces transmitted by the gears to the shaft, with an analytical model to predict the acceleration spectra at the bearing base. The hybrid approach balances accuracy, computational efficiency, and development ease, making it suitable for design-stage analysis. The model evaluates the influence of combined misalignments (axial, radial, and yaw) on vibration levels, which is more realistic than individual misalignments. Results from the hybrid model show a strong correlation (0.98) with experimental data, with discrepancies not exceeding 15%. The study highlights that radial and angular misalignments significantly influence vibration spectra, while axial misalignment has minimal impact. The proposed model offers a computationally efficient alternative to fully dynamic simulations, providing valuable insights for gear system design and misalignment diagnosis
Modelo basado en la cadena de valor para el establecimiento del costo de una carrera de pregrado
No full textEl costo involucrado en una Carrera de Pregrado es un problema que se ha enfrentado desde diferentes ángulos, sin embargo, sigue siendo un fenómeno que alcanza en el caso de Chile, incluso a las Universidades del Estado. Nosotros enfrentamos la situación bajo la construcción de un modelo en donde utilizamos como base las actividades que desarrolla una organización y que se definen en función de la producción en su acepción genérica derivada de Porter (2002) en la Cadena de Valor. Está, definió un conjunto de actividades que interactúan y contribuyen a una posición de costo. El Valor es lo que un comprador está dispuesto a desembolsar por lo que la organización le proporciona (Olmedo, Olmedo y Plazaola, s.f.), por lo tanto, el valor que exceda el costo establece un superávit organizacional. En el caso del funcionamiento de una Carrera Universitaria, las actividades primarias son consideradas en este estudio, como los cursos anuales desarrollados y como actividades de apoyo, aquellas generadas centralizadamente que cooperan con las actividades primarias. Los resultados son coherentes con el problema y reflejan entre otros, la carga que significan las horas adicionales asignadas a una asignatura de un período particular y el costo asociado a períodos en particular
Corrigendum to “Understanding ground-nesting habitat selection by waterbirds to prioritize invasive predator control on islands” [Basic and Applied Ecology Volume 78, August 2024, Pages 14-22]
No full textThe authors regret that two errors occurred during the preparation of their article: Title page: Author name Gabriela Flores-Brenner should read Gabriela Flores-Benner. Discussion: paragraph 1, next-to-last sentence should read: The relative abundance of nests on the main island reported by Schüttler et al. (2009) was higher than in this study (upland geese: 1.18 nests/km in the 2005/2006 breeding period and 1.22 nests/km in 2006/2007 versus 0.3 nests/km; flightless steamer ducks: 0.33 nests/km in 2005/2006 and 0.39 nests/km in 2006/2007 nests/km versus 0.01 nests/km). The authors would like to apologise for any inconvenience caused
Human Use of Bird Resources in the Northeastern Coasts of the Beagle Channel (Tierra del Fuego, Southern South America) During the Late Holocene
No full textIn Tierra del Fuego, current knowledge of bird use among hunter-gatherer societies is primarily based on research conducted in the central Beagle Channel, whereas little is known about this activity in different southeastern sectors of the island. This study examines bird remains from Late Holocene shell middens located in Moat Bay, at the eastern end of the Beagle Channel. By analyzing taxonomic diversity, procurement, and processing strategies, this paper contributes new insights into avifaunal exploitation in a locality that has received limited archaeological attention. The results indicate that bird exploitation, in terms of resource provisioning and processing patterns, is concentrated on cormorants (Phalacrocoracidae, Leucocarbo sp.), and also on penguins (Spheniscidae), and albatrosses (Diomedeidae) to a lesser extent. Although these outcomes align with previously documented regional trends, distinct local patterns emerge, such as a notable proportion of immature specimens in certain assemblages and taxa. This record suggests that cormorant exploitation could have occurred in colonies during the spring/summer seasons. Additionally, incidental exploitation of certain taxa, such as ducks or geese (Anatidae) and seagulls (Laridae), is documented, and we discuss the incorporation of passerines (Passeriformes) in the archaeological record. Variability in the avifaunal record at Heshkaia locality suggests that Late Holocene bird exploitation involved both regional strategies and localized adjustments, with evidence of seasonal hunting and diverse methods of capture. The predominance of cormorants and the occasional exploitation of procellarids reflect flexible subsistence practices adapted to specific environmental and cultural contexts
Recombinant protein CP01850 adjuvanted with Iridea cordata or Sacorpletis skottibergii lipid extracts protected mice against infection by Corynebacterium pseudotuberculosis
No full textRecently, new immunomodulatory compounds have benn sought as effective adjuvants in vaccine development. In this context, the bioactive substances from macroalgae stand out, as they can satisfactorily activate an immune response against infectious diseases, such as caseous lymphadenitis (CLA), caused by Corynebacterium pseudotuberculosis. This study aimed to evaluate the adjuvant activity of Iridea cordata and Sacorpletis skotibergii lipid extracts associated with the protein rCP01850 against infection by C. pseudotuberculosis in a murine model. Five groups of ten BALB/c mice each were inoculated with 0.9% saline (G1), rCP01850 (G2), rCP01850 + saponin (G3), rCP01850 + Iridea cordata (G4), and rCP01850 + Sacorpletis skotibergii (G5). Two doses of vaccine were administered with a 21-day interval between doses. After that, the animals were challenged with 2 x 10(4) UFC of the MIC-6 strain. Experimental groups G4 and G5 presented protection rates of 60 and 70%, respectively. The production levels of total IgG and its IgG1 and IgG2a isotypes were significantly increased in G4 and G5 after the forty-second day of immunization. In addition, the expression of the cytokines IL-4, IL-12, IL-10, and IFN-gamma significantly increased in G4 and G5 when compared to the negative control (G1). In turn, IL-17 and TNF-alpha had significant expression levels in G4 when compared to the other experimental groups (p < 0.05). The results show that subantarctic macroalgae extracts associated with rCP01850 induced substantial levels of humoral and cellular immune response and protected immunized animals against the challenge
Evolution of glacial lakes in Southern Patagonian Icefield between 1986 and 2023
No full textThis article presents satellite-based monitoring of glacial lakes located in the vicinity of the Southern Patagonian Icefield (SPI) between 1986 and 2023, with a focus on year-by-year changes between 2015 and 2023. Glacial lakes in this region are of importance as their growth represents an indirect response to climate change and has implications for local ecosystems, tourism, and recreation. The growth of glacial lakes also has implications regarding the potential generation of Glacial Lake Outburst Floods (GLOFs), and this study therefore enables a better understanding of the evolution of the GLOF hazard associated with the SPI. Using a total of 93 Landsat and Sentinel-2 satellite images, glacial lakes were mapped with the aid of the Normalized Difference Water Index (NDWI) and visual analysis and differentiated into three distinct types (moraine-dammed, bedrock-dammed, and ice-dammed). In addition, the volume of glacial lake water was estimated using an empirical area-volume scaling approach. Our results show that the number, area and volume of glacial lakes around the SPI have increased by 34%, 29% and 31%, respectively, between 1986 and 2023. The most recent inventory (2023) identified 313 lakes with a total area of 639.09 km 2 and a total volume of 34.84 km 3 . Of the lakes identified in 2023, moraine-dammed lakes accounted for the largest portion (165), followed by bedrock-dammed lakes (76) and ice-dammed lakes (72). A temporal analysis of the lakes by type revealed that (1) bedrock-dammed lakes exhibited the greatest stability, (2) moraine-dammed lakes showed the most significant growth in number and total area, with the number of lakes stagnating after 2016, and (3) ice-dammed lakes were the most dynamic and variable. Overall, our results highlight that the glacial lakes of the SPI are undergoing complex changes in response to glacial decline, and continued monitoring is necessary to quantify their impact on future glacier mass balance, GLOF hazard and risk, ecological change and the broader socio-economics of the region
The First Firn Core From the Cordillera Darwin Icefield: Implications for Future Ice Core Research
No full textThe Southern Hemisphere westerly winds (SHWWs) (45-65 degrees S) are important regulators of the Southern Hemisphere climate. The scarcity of observational records at the core of the wind belt hinders our understanding of the environmental impact and long-term variability of the westerly winds. The Cordillera Darwin Icefield (CDI) (54-55 degrees S) is favorably located to capture environmental changes at the current core of the SHWW belt. Here, we present chemical and microparticle records from the first firn core from the CDI. We evaluate regional climate reanalysis data using in situ automatic weather station observations and apply a downscaling approach to study regional-to-local environmental conditions at the firn core site. We use these records to assess the preservation of local-to-regional environmental information in the firn. Our CDI firn core records present minor post-depositional disruptions, preserving the original seasonality of locally sourced impurities. Local surface air temperature and melt estimations suggest the icefield has been progressively exposed to surface melt conditions, but not enough to produce significant melt at the firn core site. Air mass trajectories demonstrate air parcels are directly transported from local marine and terrestrial environments, establishing a route for the transport and deposition of chemical compounds and aerosols to the firn core site. These results highlight the potential of high elevation sites (>2,000 m a.s.l) in the CDI to hold valuable paleoenvironmental records directly from the core of the SHWW belt, records which are currently threatened by increasing surface air temperatures