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  • Encuentra documentos institucionales producidos por la Universidad Andrés Bello, como memorias anuales, informes de autoevaluación, libros y revistas.
  • Encuentra los trabajos de titulación de pregrado y postgrado como tesis, memorias, seminarios, entre otros documentos generados por las diversas Facultades, además de artículos de investigación (papers).
  • Material docente y recursos de aprendizaje abiertos de profesores de la Universidad Andrés Bello

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Uncovering population structure in the Humboldt penguin (Spheniscus humboldti) along the Pacific coast at South America
(Public Library of Science, 2019-05) Dantas, Gisele P.M.; Oliveira, Larissa R.; Santos, Amanda M.; Flores, Mariana D.; De Melo, Daniella R.; Simeone, Alejandro; González-Acuña, Daniel; Luna-Jorquera, Guillermo; Le Bohec, Céline; Valdés-Velásquez, Armando; Cardeña, Marco; Morgante, João S.; Vianna, Juliana A.
The upwelling hypothesis has been proposed to explain reduced or lack of population structure in seabird species specialized in food resources available at cold-water upwellings. However, population genetic structure may be challenging to detect in species with large population sizes, since variation in allele frequencies are more robust under genetic drift. High gene flow among populations, that can be constant or pulses of migration in a short period, may also decrease power of algorithms to detect genetic structure. Penguin species usually have large population sizes, high migratory ability but philopatric behavior, and recent investigations debate the existence of subtle population structure for some species not detected before. Previous study on Humboldt penguins found lack of population genetic structure for colonies of Punta San Juan and from South Chile. Here, we used mtDNA and nuclear markers (10 microsatellites and RAG1 intron) to evaluate population structure for 11 main breeding colonies of Humboldt penguins, covering the whole spatial distribution of this species. Although mtDNA failed to detect population structure, microsatellite loci and nuclear intron detected population structure along its latitudinal distribution. Microsatellite showed significant Rst values between most of pairwise locations (44 of 56 locations, Rst = 0.003 to 0.081) and 86% of individuals were assigned to their sampled colony, suggesting philopatry. STRUCTURE detected three main genetic clusters according to geographical locations: i) Peru; ii) North of Chile; and iii) Central-South of Chile. The Humboldt penguin shows signal population expansion after the Last Glacial Maximum (LGM), suggesting that the genetic structure of the species is a result of population dynamics and foraging colder water upwelling that favor gene flow and phylopatric rate. Our findings thus highlight that variable markers and wide sampling along the species distribution are crucial to better understand genetic population structure in animals with high dispersal ability. © 2019 Dantas et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Natural disaster preparedness in a multi-hazard environment: Characterizing the sociodemographic profile of those better (worse) prepared
(Public Library of Science, 2019-04) Bronfman, Nicolás C.; Cisternas, Pamela C.; Repetto, Paula B.; Castañeda, Javiera V.
The growing multi-hazard environment to which millions of people in the world are exposed highlights the importance of making sure that populations are increasingly better prepared. The objective of this study was to report the levels of preparedness of a community exposed to two natural hazards and identify the primary sociodemographic characteristics of groups with different preparedness levels. A survey was conducted on 476 participants from two localities of the Atacama Region in the north of Chile during the spring of 2015. Their level of preparedness at home and work was assessed to face two types of natural hazards: earthquakes and floods.The findings show that participants are significantly better prepared to face earthquakes than floods, which sends a serious warning to local authorities, given that floods have caused the greatest human and material losses in the region’s recent history of natural disasters. Men claimed to be more prepared than women to face floods, something that the authors attribute to the particular characteristics of the main employment sectors for men and women in the region. The potential contribution of large companies on preparedness levels of communities in the areas in which they operate is discussed. The sociodemographic profile of individuals with the highest levels of preparedness in an environment with multiple natural hazards are people between 30 and 59 years of age, living with their partner and school-age children. The implications of the results pertaining to institutions responsible for developing disaster risk reduction plans, policies and programs in a multi-hazard environment are discussed. © 2019 Bronfman et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Single and combined effect of retinoic acid and rapamycin modulate the generation, activity and homing potential of induced human regulatory T cells
(Public Library of Science, 2017-07) Candia, Enzo; Reyes, Paz; Covian, Camila; Rodriguez, Francisco; Rodriguez, Francisco; Wainstein, Nicolas; Morales, Jorge; Mosso, Claudio; Rosemblatt, Mario; Fierro, Juan Alberto
Adoptive transfer of CD4+CD25+FOXP3+ regulatory T cells (Treg cells) has been successfully utilized to treat graft versus host disease and represents a promising strategy for the treatment of autoimmune diseases and transplant rejection. The aim of this study was to evaluate the effects of all-trans retinoic acid (atRA) and rapamycin (RAPA) on the number, phenotype, homing markers expression, DNA methylation, and function of induced human Treg cells in short-term cultures. Naive T cells were polyclonally stimulated and cultured for five days in the presence of different combinations of IL-2, TGF-β1, atRA and RAPA. The resulting cells were characterized by the expression of FOXP3, activation, surface and homing markers. Methylation of the Conserved Non-coding Sequence 2 was also evaluated. Functional comparison of the different culture conditions was performed by suppression assays in vitro. Culturing naive human T cells with IL-2/TGFβ1 resulted in the generation of 54.2% of Treg cells (CD4+CD25+FOXP3+) whereas the addition of 100 nM atRA increased the yield of Treg cells to 66% (p = 0.0088). The addition of RAPA did not increase the number of Treg cells in any of these settings. Treg cells generated in the presence of atRA had an increased expression of the β7 integrin to nearly 100% of the generated Treg cells, while RAPA treated cells showed enhanced expression of CXCR4. The differential expression of homing molecules highlights the possibility of inducing Treg cells with differential organ-specific homing properties. Neither atRA nor RAPA had an effect on the highly methylated CNS2 sites, supporting reports that their contribution to the lineage stability of Treg cells is not mediated by methylation changes in this locus. Treg cells generated in the presence of RAPA show the most potent suppression effect on the proliferation of effector cells. © 2017 Candia et al. This is an open access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.
Bombas de pozo solares en el mercado doméstico residencial
(Universidad Andrés Bello, 2021) González Tognarelli, María Isabel; González Droguett, Víctor Manuel; Mella Zamorano, Claudio Alexis; Zúñiga San Martín, Mauricio
El mercado de bombas de pozos solares es un segmento que está en pleno desarrollo, gracias a las tendencias del uso de las energías renovables y a los cambios demográficos de los habitantes de zonas urbanas a zonas rurales, en búsqueda de una mejor calidad de vida familiar. Este cambio demográfico ha provocado un aumento explosivo en la venta de parcelas de agrado en zonas rurales sin factibilidad de agua y eléctrica generando la necesidad de los compradores de extraer agua de pozo para el consumo doméstico en sus parcelas. El objetivo de este proyecto es evaluar la factibilidad de crear una unidad de negocio en la empresa Koslan SPA. que permita cubrir la necesidad de los compradores de las parcelas de agrado. Para cumplir con este objetivo se realizará un análisis de micro y macro entorno, en donde se consideran variables que podrían afectar o beneficiar al proyecto.
Multi-Mode Master-Slave Control Approach for More Modular and Reconfigurable Hybrid Microgrids
(Institute of Electrical and Electronics Engineers Inc., 2023) D'Antonio, Diego S.; Lopez-Santos, Oswaldo; Navas-Fonseca, Alex; Flores-Bahamonde, Freddy; Perez, Marcelo A.
The increasing demand for energy and the high penetration of distributed energy resources require the evolution of current electrical systems toward smarter and more reliable electric grids. In this regard, microgrids (MG) play a vital role in integrating distributed energy resources (DER), loads, and storage systems. However, microgrid architectures lack versatility and flexibility in terms of control, limiting their expansion. This paper presents a multi-mode master-slave control approach to increase the flexibility of DC-coupled hybrid microgrids. The proposed control scheme allows optimal coordination of the power units connected to each bus. Coordination among buses is also achieved through interlinking and interfacing converters; thus, ensuring the reliable operation of the microgrid. Moreover, this approach considers the possible expansion of the capacity of the MG, providing more degrees of freedom for optimization and control. An MG with two DC distribution buses connected to the main grid is selected as a case study to develop dynamic modeling and establish a control architecture. The advantages of the proposed control are discussed via MATLAB simulation results considering the operation of the MG in several scenarios. © 2013 IEEE.