Browsing by Author "Vasquez, Felipe"

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    Assessing the socio-economic and land-cover drivers of wildfire activity and its spatiotemporal distribution in south-central Chile
    (2022) Pozo, Rocio A.; Galleguillos, Mauricio; Gonzalez, Mauro E.; Vasquez, Felipe; Arriagada, Rodrigo
    Sustained human pressures on the environment have significantly increased the frequency, extent, and severity of wildfires, globally. This is particularly the case in Mediterranean regions, in which human-caused wildfires represent up to 90% of all recorded wildfire ignitions. In Chile, it has been estimated that nearly 90% of wildfires are related to human activities, and that their frequency and distribution have steadily increased over the last decade. Despite this, the role of socio-economic factors in driving wildfire activity and its spatiotemporal distribution remains unclear. In this study, we assess the association between socio-economic drivers and spatiotemporal patterns of wildfires in the Mediterranean region of south-central Chile over the period 2010-2018. Our results show that 98.5% of wildfires are related to human activities, either accidentally (58.2%) or intentionally (36.6%). Wildfires occurred primarily during the summer months and their density at the commune-level was associated with increased road access, as well as with the percentage of land covered by agriculture, exotic tree plantations, and native forest. Wildfire activity at the commune-level was also related to socio-economic variables such as population density, proportion of indigenous population, and unemployment rate, although such associations varied considerably depending on the region and on whether the wildfire was started accidentally or intentionally. Our study provides a comprehensive and interdisciplinary assessment of the complex ways in which land-cover and socio-economic factors drive the distribution of wildfire activity in south-central Chile. It represents an important guide for policy-making, as well a baseline for research into strategies aimed at predicting and mitigating wildfire activity at both local and national levels.
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    Effective Targeting and Additionality: Evaluating the DL 701 Reforms for Afforesting Erodible Land in Southern Chile
    (2021) Niklitschek, Mario; Labbe, Rodrigo; Maria Alzamora, Rosa; Vasquez, Felipe
    We analyze the targeting and additionality of the Chilean afforestation program reforms implemented in the mid-1990s. Propensity score matching estimates are obtained by potential erosion categories using random area sample data. The additional afforestation percentage is estimated to be larger for none or low and very severe categories of potential erosion parcels. Even though the program helped maintain forest cover to highly erodible land, afforested parcels with high opportunity costs and possible negative amenity benefits are also attributed to the program. To improve the cost-effectiveness and to avoid misallocation of land and water resources, more effective targeting is required. (JEL Q23, C14)
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    History, control, epidemiology, ecology, and economy of the invasion of European rabbits in Chile: a comparison with Australia
    (2023) Correa Cuadros, Jennifer Paola; Flores Benner, Gabriela Verónica; Munoz-Rodriguez, Manuel Andres; Briceno, Cristobal; Diaz, Miguel; Strive, Tanja; Vasquez, Felipe; Jaksic Andrade, Fabián
    We reviewed existing studies on the European rabbit in Chile regarding history, control, epidemiology, ecology, and economic impacts, comparing them with Australia's accumulated knowledge about the same topics. We focused especially on the resulting gaps and challenges to orient efforts toward controlling and managing rabbits in Chile. The European rabbit was first introduced to central Chile in the mid-eighteenth century and was reported as naturalized by 1884. It is among the seven invasive species that most affect Chilean ecosystems and their productive uses. The strongest rabbit impacts have been reported on Chilean islands and in the mainland’s sclerophyllous forest biome. Released rabbits colonized both Juan Fernández Archipelago in 1935, becoming a harmful species damaging endemic vegetation and nesting bird populations, and Tierra del Fuego Island in 1936, becoming competitors for forage with sheep. The sclerophyllous forest in continental Chile is one of the five Mediterranean ecosystems of the world and one of the 34 critical “hotspots” for conserving the planet’s biodiversity. Here, released rabbits and escapees have changed the spatial distribution of native shrubs and herbs, impeding the regeneration of the native matorral. Overall, the impacts of this species during the last 70 years in Chile have been addressed chiefly from a community-ecological perspective, and applied research is lacking for improving public policies and efficient management of this invader. It is urgent to determine the geographical distribution, population size, and drivers of rabbit dynamics to predict their spread and outbreaks. Also, it is necessary to better understand their effects on Chilean natural ecosystems and agroecosystems to assess their economic impacts on biodiversity and production. In addition, it is essential to research pathogens such as Myxoma virus or Lagovirus in Chile, toward determining their prevalence, virulence, and corresponding rabbit immunity, to estimate and potentially harness any contributions such pathogens could make towards controlling populations through biological agents.
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    Multiphysics simulation of laser-material interaction during laser powder depositon
    (SPRINGER LONDON LTD, 2012) Vasquez, Felipe; Andres Ramos Grez, Jorge; Walczak, Magdalena
    This work reports a theoretical and numerical study of the parameters related to the process of laser powder deposition through a lateral nozzle. For this purpose, a 3D quasi-stationary finite element model was developed analytically and implemented numerically. The proposed model estimates the shape of the melt pool depending on the process parameters including scanning speed, powder mass flow, laser power, and physical properties. Also, phase transformations and physical properties (density, thermal conductivity, and specific heat) vary as function of temperature. In addition, thermo-capillary forces and their effect on fluid flow inside the melt pool are considered. The obtained set of equations coupled through the temperature variable was solved using COMSOL Multiphysics. The results are presented and compared with previously obtained experimental data, in which chromium powder was deposited, allowing validation of the model. Finally, variations at the melt pool geometry in terms of the operational parameters are analyzed. This model aims at estimation of melt pool geometry during laser powder deposition in time reasonably short to allow for predictable process control.