Universidad de Magallanes
Not a member yet
1947 research outputs found
Sort by
Humedales costeros en mares interiores de Isla Grande de Chiloé y Golfo de Reloncaví, Región de Los Lagos, Chile: comparación de flora, vegetación y degradación antrópica
No full textRESUMEN: Con metodologías de sistemática tradicional, fitosociológica y estadística multivariada se comparó la flora y la vegetación de tres humedales costeros de mares interiores: Huildad y Putemum en la isla grande de Chiloé y Quillaipe en el Golfo de Reloncaví, en la Región de Los Lagos, en el Sur de Chile. La flora total de ellos está formada por 91 especies de las cuales, 75 son nativas y 16 introducidas. También a ella pertenecen 62 Dicotiledóneas, 20 Monocotiledóneas y 9 Pteridófitos. En el espectro biológico dominan plantas leñosas y hierbas perennes. Cincuenta y seis especies son terrestres, 26 palustres, 5 epifíticas, 2 psamófitas y 3 plantas acuáticas (hidrófitos). Setenta especies son de ambientes no salinos, 16 son halófilos y 5 indiferentes. Helechos se encontraron sólo en Chiloé, con una mayor extensión de vegetación boscosa. Las especies nativas disminuyen de sur a norte y las introducidas de norte a sur, de la misma manera se comportan las plantas leñosas y las hierbas perennes. Sólo en Quillaipe abundaron los helófitos (plantas palustres) y caméfitos de marismas. Se presentó una correlación negativa entre número de habitantes de la ciudad más cercana con el número de especies presentes. La similitud florística entre humedales es muy baja. Se distinguieron 5 formaciones vegetales: bosques, matorrales, praderas, arroyos dulciacuícolas y marismas. En los tres humedales se presentaron en total 16 asociaciones vegetales de las cuales sólo 2 son comunes a ellos, por lo que también se presentó baja similitud vegetacional. Once asociaciones son primarias, 4 secundarias y 1 terciaria (matorral de Ulex europaeus). En general, los humedales estudiados son menos diversos en flora y vegetación que los del mar abierto y de más al norte, en Chile
Maximal pulmonary ventilation and lactate affect the anaerobic performance in young women exposed to hypobaric hypoxia
No full textBackground: Athletes, tourists, and mining workers from all over the world ascend daily to an altitude greater than 3.000 meters above sea level to perform different activities, all of which demand physical effort. A ventilation increase is the first mechanism once the chemoreceptors perceive hypoxia, and is key to maintaining blood oxygen levels during acute exposure to high altitudes and to buffering lactic acidosis during exercise. It has been observed that gender is a variable that can influence the ventilatory response. Still, the available literature is limited due to the few studies considering women as study subjects. The influence of gender on anaerobic performance and its effects under high altitudes (HA) environments have been poorly studied. Objective: The objectives of this study were to evaluate anaerobic performance in young women exposed to high altitudes and to compare the physiological response to multiple sprints between women and men measured by ergospirometry. Methodology: Nine women and nine men (22.9 +/- 3.2 years old) carried out the multiple-sprint anaerobic tests under two conditions, sea level and high altitudes. Results: In the first 24 h of exposure to a high altitudes, lactate levels were higher in women than those in men (2.57 +/- 0.4 Mmol/L, 2.18 +/- 0.3 Mmol/L, respectively; p 0.005). Third, there is a positive correlation between lactate levels prior to an anaerobic test and the ventilatory response developed by subjects at high altitudes (R2 = 0.33, slope = -41.7, and p < 0.05). Lastly, this ventilatory response can influence VO2peak (R2 = 0.60, slope = 0.02, and p < 0.001). Conclusion: This study provides insights into the mechanisms behind the reduced respiratory capacity observed in women during an anaerobic exercise test at high altitudes. An acute response to HA showed a greater work of breathing and increased the drive ventilatory response. It is possible to postulate the differences in the fatigue-induced metaboreflex of the respiratory muscles and aerobic-anaerobic transition between genders. These results on multiple sprint performance and the influences of gender in hypoxic environments deserve further investigation
Guinea Grass (Megathyrsus maximus) Fibres as Sorbent in Diesel Bioremediation
No full textIn this study, the ability of a natural grass named Megathyrsus maximus (Guinea grass) as a sorbent for cleaning up diesel spills in water was investigated. Fourier transform infrared (FTIR) spectroscopy was used to identify the physicochemical properties of untreated and treated GG. Several parameters influencing the efficiency of oil absorbed by guinea grass were optimised using established One Factor at a Time (OFAT) and followed by Response Surface Methodology (RSM) approaches. The optimised parameters include heat treatment, time of heating, packing density, and diesel concentration, with only the significant factors proceeded to statistical optimisation through RSM. As a result of OFAT analysis, 18.83 mL of oil was absorbed at 110 degrees C for 15 min time of heating, with packing density of 14 g/cm(3) and oil concentration of 10% (v/v). Through RSM, the predicted model was significant, confirming that packing density and oil concentration significantly influenced the efficiency of oil absorption by GG. The software predicted an oil absorption efficiency of 16.64 mL, whereas the experimental model validated the design with 22.33 mL of oil absorbed at a constant temperature and time, respectively. The RSM technique has proven better efficiency and effectiveness in absorbing oil compared to OFAT. This research advances our understanding of the utilisation of natural sorbents as a diesel pollution remediation strategy
Motivations and perceptions that influence the process of choosing Pedagogical careers in Chilean students with different profiles of study aspirations
No full textINTRODUCTION. Based on three different student profiles (ephemeral aspirations, vocational aspirations, and secondcareer students), we investigate the motivational and perceptual factors that influence Chilean university students to choose a teaching program. METHOD. A qualitative analysis was conducted of 23 semi-structured interviews and a focus group discussion. The data were analyzed under the theoretical perspective of career choice and motivations to become a teacher. RESULTS. The results show similarities in each of the stages of the career choice process, but also significant differences in terms of perceptions of the teaching profession and the motivational variables that lead students to choose a teaching career, in the case of students with vocational aspirations and second-career, or to opt for another career, as in the case of students with ephemeral aspirations. CONCLUSION. It highlights the influence of the educational centers in the choice to follow or not a pedagogical career to the influence that they exercise in this decision and in the perceptions of students, the opinions of family members, teachers and peers. Students show a predominance of altruistic and intrinsic motivations over extrinsic motivations
Revealing the hidden biodiversity of Antarctic and the Magellanic Sub-Antarctic Ecoregion: A comprehensive study of aquatic invertebrates from the BASE Project
No full textBackgroundAntarctica, its outlying archipelagoes and the Magellanic Subantarctic (MSA) ecoregion are amongst the last true wilderness areas remaining on the planet. Therefore, the publication, citation and peer review of their biodiversity data are essential. The new Millennium Institute Biodiversity of Antarctic and Subantarctic Ecosystems (BASE), a Chilean scientific initiative funded by the National Agency of Research and Innovation, contributes 770 new records of aquatic invertebrates as a point of reference for present-day biodiversity research at these latitudes.New informationThe occurrence dataset presented here has never been released before and is the result of the systematic recording of occurrences of several taxa across the Antarctic, Subantarctic and Magellanic Subantarctic ecoregions. We collected data from marine and freshwater invertebrates across numerous samplings from 2008 to 2023. From the 770 occurrences, we identified 160 taxa, 125 at species level and 35 at the genus level. The database has been registered in the Global Biodiversity Information Facility (GBIF). The publication of this data paper was funded by the Belgian Science Policy Office (BELSPO, contract n(degrees)FR/36/AN1/AntaBIS) in the Framework of EU-Lifewatch as a contribution to the SCAR Antarctic biodiversity portal (biodiversity.aq
The ancient inhabitants of the Chonos Archipelago (∼43°-47°S): Characterization of maritime hunter-gatherers from Western Patagonia using mitochondrial DNA
No full textBackground: Within the southern end of South America, Western Patagonia arises as an intricate region of channels, fjords, and islands. This region holds evidence of human occupation since ca. 14,500 cal years BP, with distinctive maritime adaptations developing around 7300 cal years BP. Historically, three major populations were characterized as part of these maritime traditions: Yarnana, Kawesqar, and Chono. The arrival of European population had a profound impact in these communities, affecting their lifestyles, territory and population size and health. The northernmost populations, living within the Chonos Archipelago, were the most affected and the least known communities from Western Patagonia. Objectives: This research aims to characterize the mitochondrial DNA diversity of ancient individuals from the Chonos Archipelago, evaluating their genetic affinities with other ancient and present-day populations from Patagonia. Materials and Methods: A total of 46 individuals from the region were sampled for ancient DNA analysis. Mitochondrial DNA haplogroups were characterized and compared with ancient and present-day populations from Southern South America. Results: All individuals from the Chonos Archipelago belong to C and D haplogroups, particularly to C1b, C1b13, D1, D1g, and D4h3a5. As a group, the individuals from Chonos Archipelago lay closer to ancient individuals from Kawesqar territory, immediately south of them. Using mitogenomes, we characterized two new D4h3a5 lineages almost exclusively associated with populations from Western Patagonia. Discussion: Our results contribute to the understanding of the peopling and human interactions in Western Patagonia, suggesting these unique maritime traditions developed within local populations, genetically associated with earlier terrestrial populations
Nutritional status and delivery in a cohort of pregnant women controlled in a CESFAM of Primary Health Care, Punta Arenas, Chile
No full textIn Chile, the group of pregnant women controlled in Primary Health Care has good adherence to prenatal controls and has favorable characteristics for the development of preg-nancy. However, high prevalence of overweight and obesity and chronic pathologies that could be associated with excess malnutrition of the pregnant woman are reported. Objective: To characterize pregnant beneficiaries of the Family Health Center (CESFAM) Dr. Thomas Fenton of the city of Punta Arenas, associating the nutritional condition at delivery and characteristics of the newborn. Methods: Descriptive cross-sectional research. The universe consisted of 171 pregnant women under control between January 1, 2016 and July 31, 2017. The information was obtained from secondary source, from the anonymized database of the CESFAM prenatal control program. Results: The average weight at the beginning of pregnancy was 68.7&PLUSMN; 17.1 kg, 76.6&PLUSMN; 17.4 kg at 20 weeks and 75.2&PLUSMN; 15 kg at term. The distribution of nutritional status at the beginning of pregnancy was: 5.2% were underweight, 34.2% had normal nutritional status, 26.9% were overweight and 33.5% were obese. In the postpartum evaluation the distribution was: 3.4% underweight, 24% normal, 36.8% overweight and 35.8% obese. In the group studied there were 57.7% of cesarean deliveries, and 67.2% of them occurred in overweight women. Obese women had newborns with a slightly higher average weight than those in the other nutritional categories. Discussion: The results are consistent with information from Chilean official sources and scientific evidence. Conclusions: The prevalence of overweight and obesity at the end of pregnancy was 72.6%. Overall, excess malnutrition increased 12.2% between the beginning and the end of pregnancy
Mujeres en situación discapacidad: Cuando el acceso a derechos reproductivos sigue siendo un privilegio
No full textEste capítulo analiza la evidencia científica respecto al abordaje de los derechos reproductivos de las mujeres en situación de discapacidad y las barreras a las que se enfrentan
DeLiAn - a growing collection of depolarization ratio, lidar ratio and Ångstrom exponent for different aerosol types and mixtures from ground-based lidar observations
No full textThis paper presents a collection of lidar-derived aerosol intensive optical properties for several aerosol types, namely the particle linear depolarization ratio, the extinction-to-backscatter ratio (lidar ratio) and the angstrom ngstrom exponent. The data collection, named DeLiAn, is based on globally distributed, long-term, ground-based, multiwavelength, Raman and polarization lidar measurements, conducted mainly with lidars that have been developed at the Leibniz Institute for Tropospheric Research. The intensive optical properties are presented at two wavelengths, 355 and 532 nm, for 13 aerosol categories. The categories cover the basic aerosol types (i.e., marine, pollution, continental European background, volcanic ash, smoke, mineral dust), as well as the most frequently observed mixtures they form. This extensive collection also incorporates more peculiar aerosol categories, including dried marine aerosol that, compared to marine aerosol, exhibits a significantly enhanced depolarization ratio (up to 15 %). Besides Saharan dust, additional mineral dust types related to their source region were identified due to their lower lidar ratios (Central Asian and Middle Eastern dust). In addition, extreme wildfire events (such as in north America and Australia) emitted smoke into the stratosphere showing significantly different optical properties, i.e., high depolarization values (up to 25 %), compared to tropospheric smoke. The data collection reflects and underlines the variety of aerosol mixtures in the atmosphere and can be used for the development of aerosol-typing schemes. The paper contains the most up-to-date and comprehensive overview of optical properties from aerosol lidar measurements and, therefore, provides a solid basis for future aerosol retrievals in the frame of both spaceborne and ground-based lidars. Furthermore, DeLiAn can assist the efforts for the harmonization of satellite records of aerosol properties performed at different wavelengths
Forensic anthropological analysis of human remains recovered in Santa Cruz (Argentina) Análisis antropológico forense de restos humanos recuperados en Santa Cruz (Argentina)
No full textan older adult male subject at the time of death, while most of the associated pathologies seem to be consistent with this age range. This work aims to incorporate a new interdisciplinary forensic methodology for the region, presenting a systematic and comprehensive approach to the analysis of human remains linked to judicial cases. In the same vein, it encourages raising awareness among members of the security forces, in general, and the judicial system, in particular, about the importance of anthropological information in future forensic investigations. The following work presents the results of the forensic anthropological analysis of human remains found in the Magallanes department, Santa Cruz province, Argentina. The main objective of this work was the determination of individual characteristics (sex, age and estimation of ancestral pattern) and the detection of bone and dental pathologies for identification purposes. The results indicate that the remains might correspond t