Publicaciones académicas

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https://repositorio.uc.cl/handle/11534/7
Esta colección incluye artículos de profesores de la Pontificia Universidad Católica de Chile, publicados en revistas nacionales y extranjeras.

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    1000 years of population, warfare, and climate change in pre-Columbian societies of the Central Andes
    (2023) Lima, Mauricio; Gayo, Eugenia M.; Gurruchaga, Andone; Estay, Sergio A.; Santoro, Calogero M.
    Different Andean societies underwent processes of expansion and collapse during propitious or adverse climate conditions, resource boost or depletion along with population variations. Previous studies have emphasized that demographic collapses of polities in the Central Andes Area were triggered by warfare and the negative impacts of fluctuating climate (droughts) on crop productivity. Nevertheless, the interactions between climatic variability, demography and warfare have been less thoroughly evaluated. We develop population dynamic models to test feedback relationships between population growth, climate change and warfare in the Central Andes, where considerable regional hydroclimate variations have occurred over a millennium. Through population models, we found out that the rise and demise of social polities in the northern coast of the Central Andes appear to be a consequence of climate change. In contrast, for the highlands of Peru and the Titicaca basin, population models suggest that warfare intensity has a negative effect on population growth rates.
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    2000 years of agriculture in the Atacama desert lead to changes in the distribution and concentration of iron in maize
    (Nature Research, 2021) Ale V.E.; Fernanda P.M.; Ale V.E.; Nathalia N.; Hannetz R.; Mauricio U.; Kevin R.; Frédéric G.; Christian D.
    © 2021, The Author(s).We performed a histological and quantitative study of iron in archaeological maize seeds from prehispanic times recovered from Tarapacá, Atacama Desert. Also, we examined iron distribution changes at the cell level in embryos from ancient versus new varieties of maize. Our results show a progressive decrease in iron concentration from the oldest maize to modern specimens. We interpret the results as an effect of prehispanic agriculture over the micronutrient composition of maize.
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    3G extruded snacks enriched with catechin for high antioxidant capacity
    (Taylor and Francis, 2024) Zambrano Y.; Mariotti-Celis M.S.; Bouchon P.
    © 2023 The AuthorsExtrusion yields either an expanded product or a non-expanded pellet. Non-expanded pellets undergo subsequent indirect expansion in a separate thermal device, such as a microwave oven, resulting in a third-generation (3G) snack. The utilization of milder conditions, makes this an encouraging approach for functional food development. Currently, the effects of both processes on retaining functional ingredients and the evolution of their structure are not yet fully understood. Accordingly, this work aimed to analyze how extrusion temperature (110, 135, and 150 °C) and moisture content (27 and 31%) affect the physical characteristics of 3G expanded rice-flour products enriched with catechins, using a microstructural approach, to better understand the relationship between catechin retention, antioxidant capacity, and structure development. The results showed that products with catechin exhibited higher expansion and increased crispiness/crunchiness, with a relatively higher percentage of small pores, as revealed by X-ray microtomography. Additionally, there was a remarkable retention of catechin and antioxidant capacity (DPPH) in the expanded products, reaching nearly 100%. The preservation of antioxidant capacity in the expanded products may be attributed to the high-temperature-short-time process, which favors catechin stability, along with the dense glassy structure of the extruded pellets obtained, protecting them through encapsulation until their subsequent expansion.
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    A class of random fields with two-piece marginal distributions for modeling point-referenced data with spatial outliers
    (2022) Bevilacqua, Moreno; Caamano-Carrillo, Christian; Arellano-Valle, Reinaldo B.; Gomez, Camilo
    In this paper, we propose a new class of non-Gaussian random fields named two-piece random fields. The proposed class allows to generate random fields that have flexible marginal distributions, possibly skewed and/or heavy-tailed and, as a consequence, has a wide range of applications. We study the second-order properties of this class and provide analytical expressions for the bivariate distribution and the associated correlation functions. We exemplify our general construction by studying two examples: two-piece Gaussian and two-piece Tukey-h random fields. An interesting feature of the proposed class is that it offers a specific type of dependence that can be useful when modeling data displaying spatial outliers, a property that has been somewhat ignored from modeling viewpoint in the literature for spatial point referenced data. Since the likelihood function involves analytically intractable integrals, we adopt the weighted pairwise likelihood as a method of estimation. The effectiveness of our methodology is illustrated with simulation experiments as well as with the analysis of a georeferenced dataset of mean temperatures in Middle East.
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    A cost-benefit approach to recover the performance of roads affected by natural disasters
    (2021) Cartes, P. C.; Echaveguren, Tomás; Giné, A. C.; Binet, E. A.
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    A dynamic simulation model to support reduction in illegal trade within legal wildlife markets
    (2022) Oyanedel, Rodrigo; Gelcich, Stefan; Mathieu, Emile; Milner-Gulland, E. J.
    Sustainable wildlife trade is critical for biodiversity conservation, livelihoods, and food security. Regulatory frameworks are needed to secure these diverse benefits of sustainable wildlife trade. However, regulations limiting trade can backfire, sparking illegal trade if demand is not met by legal trade alone. Assessing how regulations affect wildlife market participants' incentives is key to controlling illegal trade. Although much research has assessed how incentives at both the harvester and consumer ends of markets are affected by regulations, little has been done to understand the incentives of traders (i.e., intermediaries). We built a dynamic simulation model to support reduction in illegal wildlife trade within legal markets by focusing on incentives traders face to trade legal or illegal products. We used an Approximate Bayesian Computation approach to infer illegal trading dynamics and parameters that might be unknown (e.g., price of illegal products). We showcased the utility of the approach with a small-scale fishery case study in Chile, where we disentangled within-year dynamics of legal and illegal trading and found that the majority (similar to 77%) of traded fish is illegal. We utilized the model to assess the effect of policy interventions to improve the fishery's sustainability and explore the trade-offs between ecological, economic, and social goals. Scenario simulations showed that even significant increases (over 200%) in parameters proxying for policy interventions enabled only moderate improvements in ecological and social sustainability of the fishery at substantial economic cost. These results expose how unbalanced trader incentives are toward trading illegal over legal products in this fishery. Our model provides a novel tool for promoting sustainable wildlife trade in data-limited settings, which explicitly considers traders as critical players in wildlife markets. Sustainable wildlife trade requires incentivizing legal over illegal wildlife trade and consideration of the social, ecological, and economic impacts of interventions.
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    A Feasible Approach to Developing Fiber-Enriched Bread Using Pomegranate Peel Powder: Assessing Its Nutritional Composition and Glycemic Index
    (2023) García, Paula; Bustamante, Andrés; Echeverría González, Francisca Cecilia; Encina, Cristian; Palma, Manuel; Sanhueza, Leyla; Sambra, Verónica; Pando, Maria Elsa; Jiménez, Paula
    The consumption of dietary fiber (DF) has been associated with a reduced incidence of non-communicable diseases. Despite various strategies implemented worldwide to increase DF intake, it remains low. Therefore, the development of new fiber-rich food products that are widely consumed could be a strategy to improve DF intake. In this study, an agro-industrial by-product, pomegranate peel powder (PPP), was used as an innovative source of DF and antioxidant. The objective was to develop a bread enriched with DF, antioxidants, and sensory characteristics by partially replacing wheat flour (WF) with PPP at levels of 0%, 2.5%, 5%, 7.5%, and 10%. Bread with 2.5% and 5% PPP was chosen for a clinical trial to evaluate glycemic response (GR) in healthy subjects and determine the bread’s glycemic index (GI). As the percentage of PPP increased, both the DF and total polyphenol content increased significantly. The highest overall acceptability was achieved with bread containing up to 5% PPP. Consumption of bread with 2.5% and 5.0% PPP significantly reduced the GI compared to the control bread, while the decrease in GR was not significant. PPP could be a potential food and low-cost ingredient to improve the bread’s nutritional quality through its contribution to DF and antioxidants.
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    A First Omics Data Integration Approach in Hass Avocados to Evaluate Rootstock-Scion Interactions: From Aerial and Root Plant Growth to Fruit Development
    (2024) Nunez-Lillo, Gerardo; Ponce, Excequel; Beyer, Clemens P.; Alvaro, Juan E.; Meneses, Claudio; Pedreschi, Romina
    Grafting, the careful selection of rootstocks and scions, has played a crucial role maintaining Chilean avocado fruit quality standards in a scenario in which climate change and drought-related issues have considerably decreased avocado fruit production in the last fifteen years. The historical use of seedling rootstocks in Chile has experienced a recent shift towards clonal rootstocks, driven by the potential to produce more consistent and predictable crops. This research aims to compare Hass avocado plants grafted on Mexicola seedling and Dusa (R) clonal rootstocks in a soilless and protected system using (i) a differential expression analysis of root and leaf samples and (ii) a fruit transcriptomic and metabolomic integration analysis to improve our understanding of rootstock-scion interaction and its impact on avocado tree performance and fruit quality. The results demonstrated that no significant transcriptomic and metabolomic differences were identified at fruit level in the ready-to-eat (RTE) stage for Hass avocado fruit from both rootstocks. However, Hass avocados grafted on the clonal rootstock showed greater aerial growth and slightly increased fruit size than the seedling rootstock due to the enrichment of cell wall-remodeling genes as revealed in leaves and fruit at harvest stage.
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    A framework for assessing and intervening in markets driving unsustainable wildlife use
    (2021) Oyanedel, Rodrigo; Gelcich, Stefan; Milner-Gulland, E. J.
    Understanding how markets drive unsustainable wildlife use is key for biodiversity conservation. Yet most approaches to date look at isolated components of wildlife markets, hindering our ability to intervene effectively to improve sustainability. To better assess and intervene in wildlife markets, we propose a framework that integrates three analytical levels. The first level, "actor", assesses the underlying motivations and mechanisms that allow or constrain how actors benefit from wildlife markets. The second level, "inter-actor", assesses the config-uration of wildlife product supply-chains and the type of competition between actors participating in wildlife markets. The third level, "market", evaluates supply-demand dynamics, quantity and price determinants, and the presence and effect of illegal products flowing into markets. We showcase the utility of the framework in a data-limited small-scale fishery case study (common hake, Merluccius gayi gayi in Chile); our mixed-method analysis provided relevant, tailored management recommendations for improving sustainability. Tackling markets driving unsustainable wildlife use needs integrated approaches that bring together the diversity of factors affecting wildlife market dynamics. (c) 2021 Elsevier B.V. All rights reserved.
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    A framework integrating plant growth with hormones and nutrients
    (2011) Krouk, G.; Gutiérrez Ilabaca, Rodrigo Antonio
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    A holistic view of nitrogen acquisition in plants
    (2011) Kraiser Miranda, Tatiana Diannela; Gutiérrez Ilabaca, Rodrigo Antonio
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    A KINETIC INTERPRETATION OF TEXTURAL CHANGES IN BLACK BEANS DURING PROLONGED STORAGE
    (1987) AGUILERA, JM; BALLIVIAN, A
    Control and roasted (80.degree.C), dry black beans (Phaseolus vulgaris) were stored for 9 months at 8, 10, 12, and/or 14% moisture content and 8.5.degree., 25.degree., and 40.degree.C. Similarly, beans heated in a solid-to-solid roaster to 51.degree., 61.degree., 72.3.degree., 80.degree., 85.5.degree., 89.5.degree., 101.degree., and 111.degree.C were maintained at 8% moisture and 25.degree.C. Final hardness increased with moisture content and temperature. Hardening at 8.5.degree. and 25.degree.C proceeded initially almost linearly reaching a constant value after 4 to 6 months while at 40.degree.C it was sigma-shaped. A pseudo-zero order kinetic model fitted for initial rates had an activation energy of 6-11.8 kcal/mol. The hardening rate at 25.degree.C paralleled the shape of the sorption isotherm.
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    A mediation analysis to disentangle relations between maternal education and early child development
    (2022) Telias, Amanda; Narea, Marigen; Abufhele, Alejandra
    Maternal education is associated with early child outcomes. However, the several mechanisms that may explain this relationship remain underexplored. Using data from 1,097 children aged 12-15 months in Chile, we estimate the maternal education gap across child cognitive and language outcomes. Following a bioecological perspective, we explore potential pathways by which maternal education might influence child development, such as child characteristics, the quantity and quality of mother-child interactions, and the availability of home stimulation. We found an average maternal education gap between children with mothers with the lowest and the highest educational levels of 0.36, 0.31, and 0.25 standard deviation in child cognition, expressive language, and receptive language, respectively. The mediational analysis showed that maternal stress and depression and the quality of the home environment mediated the relation between maternal education and child language and cognitive development.
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    “A mi papá le gustaban y a mí también”: la memoria biocultural como fundamento de la práctica agroecológica
    (2019) Monterrubio-Solís, Constanza; Barreau-Daly, Antonia; Urra, Romina; Ibarra Eliessetch, José Tomás
    El movimiento por la masificación de la agroecología está logrando abrir espacios sociales y políticos para transformar el sistema alimentario a nivel global de una manera sin precedente. La adopción del término por parte de empresas, gobiernos, círculos académicos y organismos de la sociedad civil lleva implícita una amplia gama de interpretaciones del concepto y prácticas agroecológicas. Para las y los campesinos que han practicado la agricultura familiar por generaciones, el término agroecología puede parecer una moda más entre quienes diseñan programas desde alguna distante oficina. La memoria biocultural encuentra una de sus más diversas manifestaciones en la agricultura y la alimentación. La memoria biocultural, transmitida de generación en generación, representa un acervo inmaterial y ecológico que ha permitido a la humanidad manejar un ensamble de más de 5000 especies de plantas y animales, conociendo sus respectivos cuidados dentro de sistemas más amplios, así como las preparaciones para convertirlos en una amplia gama alimentos. La memoria biocultural se manifiesta en múltiples e interrelacionadas formas de conocimientos y prácticas asociadas al clima, los suelos, los ciclos biológicos, y han sido la base de la domesticación de la agrobiodiversidad. A raíz de la homogenización del sistema agrícola global, la memoria biocultural ha sido severamente diezmada, de tal manera que la agrobiodiversidad y las prácticas asociadas a la misma se encuentran hoy en día contenidas en personas cuya labor es recordar y aplicar lo que sus predecesores les enseñaron, adaptándose a los procesos de cambio actuales. En este trabajo, encuestamos a 83 agricultores de la región de La Araucanía, Chile, con respecto a las semillas que cultivan, sus prácticas de agricultura y alimentarias. A pesar de que la mayoría de las personas encuestadas no utilizan el término “Agroecología”, sus narrativas, prácticas y la diversidad de especies que cultivan dan cuenta de que la agricultura familiar es en gran medida compatible con los principios de la agroecología. Desde la perspectiva sistémica, el cuidado del suelo, de los ciclos y de las redes de reciprocidad que se tejen en los territorios, la memoria bio-cultural es la base del acervo sobre la cual la agroecología de vincularse con el día a día de la agricultura familiar. De esta manera, si bien la Agroecología plantea una diversidad de propuestas tanto técnicas como culturales para la transformación del sistema agrícola global, el marco de la memoria bio-cultural puede enriquecer su propuesta proporcionándole raíces y significado a nivel territorial.
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    A molecular framework for the inhibition of Arabidopsis root growth in response to boron toxicity
    (2012) Aquea Zeballos, José Felipe; Vega C., Andrea; Jullian Fabres, Pastor; Arce Johnson, Jorge Patricio
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    A multipurpose portable instrument for determining ripeness in wine grapes using NIR spectroscopy
    (IEEE-INST ELECTRICAL ELECTRONICS ENGINEERS INC, 2008) Larrain, Manuel; Guesalaga, Andres R.; Agosin, Eduardo
    This paper describes the development of a noninvasive instrument that is designed to measure three parameters of ripeness in wine grapes, i.e., sugar (Brix), pH, and anthocyanin concentration. The instrument is based on near-infrared spectroscopy, and it comes in contact with the berry in the cluster without altering its ripening process. A thorough description of the calibration process for the instrument is done for the different grape varieties, e.g., Cabernet Sauvignon, Carmenere, Merlot, Pinot Noir, and Chardonnay. Samples from vineyards located in the Maipo Valley (Chile) taken during the 2003 season were processed to develop calibration models using partial least squares techniques. The models were validated in terms of root mean square error of validation and R-2 indices. The results show the great potential of this technique regarding Brix and pH measurements. For the anthocyanin concentration measurements, the results are promising but require an accurate procedure to obtain reference values for model calibration. The instrument can be useful for sampling strategies that look for optimum harvest schedules according to grape maturity in terms of not only sugar content but also pH and anthocyanin concentration.
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    A network of stress-related genes regulates hypocotyl elongation downstream of selective auxin perception
    (2021) Rigal, Adeline; Doyle, Siamsa M.; Ritter, Andres; Raggi, Sara; Vain, Thomas; O'Brien, Jose Antonio; Goossens, Alain; Pauwels, Laurens; Robert, Stephanie
    The plant hormone auxin, a master coordinator of development, regulates hypocotyl elongation during seedling growth. We previously identified the synthetic molecule RubNeddin 1 (RN1), which induces degradation of the AUXIN/INDOLE-3-ACETIC ACID (AUX/IAA) transcriptional repressors INDOLE-3-ACETIC ACID-INDUCIBLE3 (IAA3) and IAA7 in planta and strongly promotes hypocotyl elongation. In the present study, we show that despite the structural similarity of RN1 to the synthetic auxin 2,4-dichlorophenoxyacetic-acid (2,4-D), direct treatments with these compounds in Arabidopsis (Arabidopsis thaliana) result in distinct effects, possibly due to enhanced uptake of RN1 and low-level, chronic release of 2,4-D from RN1 in planta. We confirm RN1-induced hypocotyl elongation occurs via specific TRANSPORT INHIBITOR RESISTANT1 (TIR1)/AUXIN SIGNALING F-BOX (AFB) receptor-mediated auxin signaling involving TIR1, AFB2, and AFB5. Using a transcriptome profiling strategy and candidate gene approach, we identify the genes ZINC FINGER OF ARABIDOPSIS THALIANA10 (ZAT10), ARABIDOPSIS TOXICOS EN LEVADURA31 (ATL31), and WRKY DNA-BINDING PROTEIN33 (WRKY33) as being rapidly upregulated by RN1, despite being downregulated by 2,4-D treatment. RN1-induced expression of these genes also occurs via TIR1/AFB-mediated auxin signaling. Our results suggest both hypocotyl elongation and transcription of these genes are induced by RN1 via the promoted degradation of the AUX/IAA transcriptional repressor IAA7. Moreover, these three genes, which are known to be stress-related, act in an inter-dependent transcriptional regulatory network controlling hypocotyl elongation. Together, our results suggest ZAT10, ATL31, and WRKY33 take part in a common gene network regulating hypocotyl elongation in Arabidopsis downstream of a selective auxin perception module likely involving TIR1, AFB2, and AFB5 and inducing the degradation of IAA7.
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    A new method of assessing water erosion risk in forest operations based on rainfall variability
    (UNIV AUSTRAL CHILE, FAC CIENCIAS FORESTALES, 2012) Contreras, Juan; Bonilla, Carlos A.; Troncoso, Juan
    Water erosion has been a major environmental problem associated to forest harvesting operations in humid and temperate climates. The incorporation of this factor in the decision making process has been complex due to the high variability observed in rainfall intensity and magnitude. This paper presents a methodology for incorporating the temporal variability of rainfall in the planning of forest operations. We used a monthly index based on the R-RUSLE erosivity factor. This index allows knowing the most likely value of soil loss and associating a confidence level. Thus, the forest planner has an estimate of erosion rates related to the operations, and an index that reflects the rainfall variability. With this methodology it is possible to identify, for a given level of soil loss, those months in which there is a higher uncertainty. This methodology was applied to a pine plantation in Santa Barbara, Biobio Region, Chile, where the rainfall erosivity ranges from 16 MJ mm ha(-1) h(-1) to 271 MJ mm ha(-1) h(-1) depending on the month of the year.