Universidad de Magallanes
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Modelling Public Intentions to Use Innovative EV Chargers Employing Hybrid Energy Storage Systems: A UK Case Study Based upon the Technology Acceptance Model
No full textThe current study investigates public intentions to use an innovative, off-grid renewably powered EV charging technology called FEVER (Future Electric Vehicle Energy networks supporting Renewables). We report the findings of a questionnaire-based survey (QBS) conducted at a zoo in the south of England, exploring the prospect of demonstrating FEVER. The QBS was designed around a context-specific technology acceptance model (TAM) and administered both face-to-face (n = 63) and online (n = 158) from April to May 2023. The results indicate that most participants were willing to pay to use FEVER, particularly where revenue would benefit the zoo. The participants agreed they intended to use the chargers, and that they would be useful and easy to use. The participants agreed that there would be normative pressure to use the chargers, but that their use would be enjoyable. Of greatest concern was that the chargers would be blocked by others. The participants were ambivalent about concerns over charging duration and charge sufficiency. Structural equation modelling confirmed that the context-specific TAM explained 58% of people's use intentions. The core relationships of the TAM were confirmed, with 'perceived usefulness' additionally predicted by subjective norms and 'perceived ease of use' additionally predicted by anticipated enjoyment. Of the other variables, only concern that the chargers would be blocked was retained as a marginal predictor of 'perceived ease of use'. The implications of these findings for the co-design and demonstration of FEVER are discussed
Autonomic nervous system dysfunction throughout menopausal transition: A potential mechanism underpinning cardiovascular and cognitive alterations during female ageing
No full textCardiovascular diseases (CVD) and neurodegenerative disorders, such as Alzheimer's disease (AD), are highly prevalent conditions in middle-aged women that severely impair quality of life. Recent evidence suggests the existence of an intimate cross-talk between the heart and the brain, resulting from a complex network of neurohumoral circuits. From a pathophysiological perspective, the higher prevalence of AD in women may be explained, at least in part, by sex-related differences in the incidence/prevalence of CVD. Notably, the autonomic nervous system, the main heart-brain axis physiological orchestrator, has been suggested to play a role in the incidence of adverse cardiovascular events in middle-aged women because of decreases in oestrogen-related signalling during transition into menopause. Despite its overt relevance for public health, this hypothesis has not been thoroughly tested. Accordingly, in this review, we aim to provide up to date evidence supporting how changes in circulating oestrogen levels during transition to menopause may trigger autonomic dysfunction, thus promoting cardiovascular and cognitive decline in women. A main focus on the effects of oestrogen-mediated signalling at CNS structures related to autonomic regulation is provided, particularly on the role of oestrogens in sympathoexcitation. Improving the understanding of the contribution of the autonomic nervous system on the development, maintenance and/or progression of both cardiovascular and cognitive dysfunction during the transition to menopause should help improve the clinical management of elderly women, with the outcome being an improved life quality during the natural ageing process. imag
Response of lacustrine glacier dynamics to atmospheric forcing in the Cordillera Darwin
No full textCalving glaciers respond quickly to atmospheric variability through ice dynamic adjustment. Particularly, single weather extremes may cause changes in ice-flow velocity and terminus position. Occasionally, this can lead to substantial event-driven mass loss at the ice front. We examine changes in terminus position, ice-flow velocity, and calving flux at the grounded lacustrine Schiaparelli Glacier in the Cordillera Darwin using geo-referenced time-lapse camera images and remote sensing data (Sentinel-1) from 2015 to 2022. Lake-level records, lake discharge measurements, and a coupled energy and mass balance model provide insight into the subglacial water discharge. We use downscaled reanalysis data (ERA-5) to identify climate extremes and track land-falling atmospheric rivers to investigate the ice-dynamic response on possible atmospheric drivers.Meltwater controls seasonal variations in ice-flow velocity, with an efficient subglacial drainage system developing during the warm season and propagating up-glacier. Calving accounts for 4.2% of the ice loss. Throughout the year, warm spells, wet spells, and landfalling atmospheric rivers promote calving. The progressive thinning of the ice destabilizes the terminus position, highlighting the positive feedback between glacier thinning, near-terminus ice-flow acceleration, and calving flux
The 1980 Aparejo Glacier catastrophic detachment: new insights and current status
No full textThe catastrophic detachment of Aparejo Glacier (one of the three known cases in the Andes) took place on 1 March 1980 and resulted in the removal of an ice volume initially estimated to be 7.2 Mm3, which originally was 1.0 km long and covered an area of 0.2 km2. The event caused the sudden mobilization of the sliding mass 3.7 km down valley at an estimated speed of 110 km/h, causing remarkable geomorphological changes, including the obliteration of most of the glacier. 40 years after the event, we analyze new evidence: 3 ground surveys carried out in 2015 and 2016; DEMs and glacier outlines compiled from orthorectified aerial imagery pre-and post-event; GNSS data; Ground Penetrating Radar (GPR) data; a terrestrial LiDAR scan survey of 2020, together with detailed interviews with 2 direct witnesses of the event, terrestrial and helicopter-borne photographs acquired 12 days after the sudden detachment. The combined interpretation of these new data, allow us to make a more precise estimation of the pre-detachment glacier volume, 12.9 +/- 0.6 x 106 m3 and the detached ice volume of 11.7 +/- 0.6 x 106 m3 (90% of the total volume of the glacier). We also show that in the 40-year period Aparejo Glacier has recovered 12.4% of the original glacier volume, with a mean ice thickness of 19.5 m and a maximum of 40 m according to GPR data, being preserved within the same basin as the detached glacier. In recent years, the glacier has shown a mean elevation change of -3.7 +/- 1.2 m during the 2015-2020 period, with maximum thinning values greater than 8 m, which are probably caused by enhanced ablation due to climate warming and reduced precipitation during the current megadrought which started in 2010 and has lasted more than 1 decade. We conclude that under the projected scenarios of climate warming and reduced precipitation for central Chile, the risk associated to a new detachment of Aparejo Glacier is unlikely
Growth and Survival of Scallops Austrochlamys natans (Philippi, 1845) and Zygochlamys patagonica (P. P. King, 1832) in Suspended Systems and Land-Based Tanks in Chilean Patagonia
No full textThe southern scallop (Austrochlamys natans) and the Patagonian scallop (Zygochlamys patagonica) are vital species in the fisheries of Chilean Patagonia. However, overfishing has led to stock depletion, necessitating research for stock restoration and commercial production. This study aimed to evaluate the growth and survival of these scallops in suspended systems and land-based tanks across various Patagonian regions. Eight experiments were conducted, three with southern scallops and five with Patagonian scallops. For southern scallops, two experiments involved suspended systems at different shell heights and three tested land-based tanks at various temperatures (9, 11, and 13 degrees C). Patagonian scallop experiments included one suspended system in an endemic area, land-based tanks with different temperatures (9, 11, and 13 degrees C), and three suspended systems outside the species' endemic zone. In suspended systems, southern scallops grew from 15.1 to 42.7 mm (shell height) in 322 days, with a rate of 0.085 mm/day and a survival rate of 43.7%. Patagonian scallops reached 46.0 mm shell height in 466 days, with a growth rate of 0.079 mm/day and a survival rate of 57.2%. Experiments in controlled-temperature tanks revealed that 13 degrees C was the lethal temperature for southern scallops. Notably, higher growth rates occurred at temperatures between 9 and 11 degrees C. Both species show potential for future commercial cultivation, contributing to Chilean aquaculture diversification
Feeding behavior of blue whales (Balaenoptera musculus) during austral summer in northern Chilean Patagonia
No full textOver recent decades, the feeding strategies of the blue whale (Balaenoptera musculus) in the northern Chilean Patagonia have been studied mainly through visual observation and anatomical dissection, with limited direct behavioral analyses and measurements of prey distribution due to the difficulty of sampling. Here, we investigated the foraging ecology of this species during six annual research cruises (2014-2019) in the northern Chilean Patagonia, an important feeding and nursery area. We deployed 28 sound and movement recording tags (DTAGs), attached by suction cups, to measure fine-scale behaviors of this species. In addition, from 2016 to 2019, prey density and distribution were simultaneously recorded with tag data utilizing a scientific echosounder. A total of 949 foraging dives and 3,183 feeding events were detected from movement sensors throughout more than 190 hr of data, during both day and nighttime. Blue whales exhibited both shallow and deep foraging events utilizing different strategies in response to changing conditions of prey depth and density, with foraging dives recorded continuously for the whole duration of the deployments. Whales showed a higher feeding rate at night as they foraged on shallow and dispersed krill, but they exhibited a higher rate of foraging events per dive during the day, as they foraged on deep and dense krill patches. The whales used less energetically costly maneuvers when foraging near the surface, with lower values of pitch and speed. Both strategies are consistent with optimal foraging theory, as the whales minimizing energetic costs associated with feeding while simultaneously maximizing energy intake. These results provide valuable insights into the behavioral and foraging ecology of blue whales to promote specific conservation plans in the northern Chilean Patagonia
Effect of Combined Misalignments on Vibrations of a Single-Stage Spur Gear Transmission System: An Experimental Approach
No full textFailures in mechanical power transmission systems can cause serious operating problems in the systems to which they belong. Misalignments in the shafts of gear transmission systems can produce transmission errors, increased bending stress at the base of the teeth, and increased normal wear between the teeth. Because vibration analysis is very useful as a failure detection mechanism in stationary rotating equipment, the effect of shaft misalignment on vibration measurements was investigated in this study. Combined misalignments are studied because different types of misalignments occur simultaneously in real applications. The effect of a combination of axial, radial, and angular misalignments on vibration measurements in a spur gear transmission system was investigated. This study was developed through the design and construction of a test bench that allows different types of misalignment in a single-stage spur gear transmission system and vibration measurement through accelerometers installed in the support bearings. Indicators, such as kurtosis and skewness, were used to validate the results in the time domain. For the frequency domain analysis, an indicator was developed that compares the frequency spectra of misaligned conditions to the base spectrum in the aligned condition. The critical misalignment combinations were also identified. It was found that for the combined cases, the contact area between the teeth and the contact ratio were influencing factors. The quantitative effects of combined misalignments on vibration measurements were determined, which can be used as a preliminary diagnosis of this type of problem and as a basis for developing more robust prediction models
Descentralización y derechos fundamentales: nexos, retos y tensiones
No full textEl propósito del trabajo es reconstruir la discusión acerca de las relaciones existentes entre descentralización y derechos fundamentales, y sistematizar los principales argumentos que permiten afirmar que, en general, mayores niveles de descentralización favorecen un respeto y garantía más efectivo de los derechos fundamentales. No obstante, esto no es por sí mismo garantía de ello, lo que demanda la adopción de algunos resguardos adicionales para así poder enfrentar adecuadamente los retos y desafíos que la descentralización involucra
Development of food and gastronomy in the sub-Antarctic end of the world
No full textRegional food and gastronomy flourish worldwide driven by unique local foods, the remembrance of old culinary traditions, and the visitors' desire to taste memorable dishes in an environment evoking cultural heritage and geographical uniqueness. The sub-Antarctic Magellan region of Chile is the southernmost zone of the planet and is unique in centenary food and culinary practices. A detailed description of marine and terrestrial local food sources and biocultural traditions is documented. This article presents a PCF to develop local food and gastronomy in this region. Collection and analysis of bibliometric data led to three pillars supporting the FPC: the nutritional value and uniqueness of local foods and culinary traditions; a booming sustainable tourism that drives the development of gastronomic endeavors, and; lessons from past experiences in other remote places. The proposed PCF may be adapted to different regions worldwide. Recent gastronomic initiatives to implement this PCF at the Cape Horn International Center in Puerto Williams (Chile) are also described
Superoxide dismutase 2 deficiency is associated with enhanced central chemoreception in mice: Implications for breathing regulation
No full textAims: In mammals, central chemoreception plays a crucial role in the regulation of breathing function in both health and disease conditions. Recently, a correlation between high levels of superoxide anion (O2.-) in the Retrotrapezoid nucleus (RTN), a main brain chemoreceptor area, and enhanced central chemoreception has been found in rodents. Interestingly, deficiency in superoxide dismutase 2 (SOD2) expression, a pivotal antioxidant enzyme, has been linked to the development/progression of several diseases. Despite, the contribution of SOD2 on O2.-regulation on central chemoreceptor function is unknown. Accordingly, we sought to determine the impact of partial deletion of SOD2 expression on i) O2.-accumulation in the RTN, ii) central ventilatory chemoreflex function, and iii) disordered-breathing. Finally, we study cellular localization of SOD2 in the RTN of healthy mice.Methods: Central chemoreflex drive and breathing function were assessed in freely moving heterozygous SOD2 knockout mice (SOD2+/-mice) and age-matched control wild type (WT) mice by whole-body plethysmography. O2.-levels were determined in RTN brainstem sections and brain isolated mitochondria, while SOD2 protein expression and tissue localization were determined by immunoblot, RNAseq and immunofluorescent staining, respectively.Results: Our results showed that SOD2+/-mice displayed reductions in SOD2 levels and high O2.-formation and mitochondrial dysfunction within the RTN compared to WT. Additionally, SOD2+/-mice displayed a heightened ventilatory response to hypercapnia and exhibited overt signs of altered breathing patterns. Both, RNAseq analysis and immunofluorescence co-localization studies showed that SOD2 expression was confined to RTN astrocytes but not to RTN chemoreceptor neurons. Finally, we found that SOD2+/-mice displayed alterations in RTN astrocyte morphology compared to RTN astrocytes from WT mice.Innovation & conclusion: These findings provide first evidence of the role of SOD2 in the regulation of O2.-levels in the RTN and its potential contribution on the regulation of central chemoreflex function. Our results suggest that reductions in the expression of SOD2 in the brain may contribute to increase O2.-levels in the RTN being the outcome a chronic surge in central chemoreflex drive and the development/maintenance of altered breathing patterns. Overall, dysregulation of SOD2 and the resulting increase in O2.-levels in brainstem respiratory areas can disrupt normal respiratory control mechanisms and contribute to breathing dysfunction seen in certain disease conditions characterized by high oxidative stress