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A comparative study of soil metal concentrations in Chilean urban parks using four pollution indexes
(2022) Vega, Alejandra; Arce, Guillermo; Rivera, Javier I.; Acevedo, Sara E.; Reyes Paecke, Sonia; Bonilla, Carlos A.; Pasten Gonzalez, Pablo Arturo; CEDEUS (Chile)
Toxic metal enrichment in urban soils from natural and anthropogenic sources is a public health concern thatchallenges sustainable urban development. Active and legacy mining is likely a major contributor of localizedmetal pollution in resource-based economies, although other sources associated with industrial and trans-portation activities may also contribute in urban settings. In mining countries, such as Chile, with no soil qualityregulation, public policies that seek to protect human health should assess metal distribution and pollution in-dexes to guide interventions, especially in urban green spaces. To assess the role of active and legacy miningwaste sites within the urban and peri-urban areas, metal concentrations in the soils of urban parks weremeasured in this study, and four pollution indexes were calculated for four cities of Chile. Copiap ́o and Andacolloin northern Chile represented the cities with several active and legacy mining waste sites located within theurban and peri-urban areas, while conurbation La Serena-Coquimbo and Gran Santiago represented the cities inmining districts that lacked major mining waste sites within their urban perimeters. A total of 82 (Copiap ́o), 30(Andacollo), 26 (La Serena-Coquimbo), and 59 (Gran Santiago) composite surface soil samples were collectedfrom the urban parks. Considering Canadian guidelines for residential/parkland soils, the value for Cu (63 mg/kg) was found to be exceeded in 99%, 50%, 100%, and 97% of samples collected from Copiap ́o, La Serena-Coquimbo, Andacollo, and Gran Santiago, respectively. The guidelines for lead (140 mg/kg) and zinc (250mg/kg) were exceeded in less than 12% of samples collected from Copiap ́o and Gran Santiago. Arsenic was notmainly quantified (<10% quantification frequency, quantification limit = 36 mg/kg). The calculated modifiedpollution load, Nemerow, and soil quality indexes indicated that soils in the urban parks were more polluted incities with urban mine wastes, however, the pollution load index ranked higher metal pollution in Gran Santiago.This study presented the first comparative study of metals in urban parks of Chile, highlighting a large proportionof parks with soil copper concentrations above the international guidelines, while showing higher median values in cities containing urban mine waste disposal sites.
A global horizon scan for urban evolutionary ecology
(2022) Verrelli, Brian C.; Alberti, Marina; Des Roches, Simone; Harris, Nyeema C.; Hendry, Andrew P.; Johnson, Marc T. J.; Savage, Amy M.; Charmantier, Anne; Gotanda, Kiyoko M.; Govaert, Lynn; Miles, Lindsay S.; Rivkin, L. Ruth; Winchell, Kristin M.; Brans, Kristien I.; Correa, Cristian; Diamond, Sarah E.; Fitzhugh, Ben; Grimm, Nancy B.; Hughes, Sara; Marzluff, John M.; Munshi-South, Jason; Rojas Quezada, Carolina Alejandra; Santangelo, James S.; Schell, Christopher J.; Schweitzer, Jennifer A.; Szulkin, Marta; Urban, Mark C.; Zhou, Yuyu; Ziter, Carly; CEDEUS (Chile)
The impact of urbanization on biodiversity has been well documented, yet research into the complex dynamics of ecological and evolutionary processes in urban areas is still in its infancy. When novel research challenges emerge, a horizon scan exercise is an integrated approach that brings together global interdisciplinary-minded individuals to identify future research questions that can influence new collaborations and funding agenda. Our horizon scan identified 30 questions for future research in urban evolutionary ecology covering themes in fundamental ecological and evolutionary processes, temporal and spatial scales, sustainability, climate change, sociopolitical and ethical considerations, and innovation in technology. Research on the evolutionary ecology of urban areas reveals how human-induced evolutionary changes affect biodiversity and essential ecosystem services. In a rapidly urbanizing world imposing many selective pressures, a time-sensitive goal is to identify the emergent issues and research priorities that affect the ecology and evolution of species within cities. Here, we report the results of a horizon scan of research questions in urban evolutionary ecology submitted by 100 interdisciplinary scholars. We identified 30 top questions organized into six themes that highlight priorities for future research. These research questions will require methodological advances and interdisciplinary collaborations, with continued revision as the field of urban evolutionary ecology expands with the rapid growth of cities.
A simple low-cost approach for transport parameter determination in mountain rivers
(2021) Castillo, Daniela; Runkel, Robert L.; Duhalde, Denisse; Pasten Gonzalez, Pablo Arturo; Arumí, José L.; Oyarzún, Jorge; Núñez, Jorge; Maturana, Hugo; Oyarzún, Ricardo; CEDEUS (Chile)
A simplified low-cost approach to experimentally determine transport parameters inmountain rivers is described,with an emphasis on the longitudinal dispersion coefficient(DL). The approach is based on a slug injectionof table salt (NaCl) as a tracer and specificconductance readings at different locations downstream of the injection spot. Observedspecific conductance readings are fit using the advection-dispersion equation withOTIS-P, yielding estimates of cross-sectional area and longitudinal dispersion coefficientfor various stream reaches. Estimates of theDLare used to assess the accuracy of sev-eral empirical equations reported in the literature. This allowed the determination ofcomplementary transport parameters related to transient storage zones. The empiricalequations yielded rather highDLvalues, with some reaching up an order of magnitudehigher to those obtained from tracer additions and OTIS-P. Overall, the proposedapproach seems reliable and pertinent for river reaches of ca. 150 m in length.
Accessibility Indicators for the Geographical Assessment of Transport Planning in Latin-America Metropolitan Area
(MDPI, 2021) Martínez, Marcela ; Rojas Quezada, Carolina Alejandra; Condeço-Melhorado, Ana; Carrasco, Juan Antonio; CEDEUS (Chile)
Accessibility represents a key element in strengthening developed regions in terms of investment in transportation infrastructure. Accessibility is also an equity indicator to measure the ease with which a specific location achieves desired outcomes as well as the spillover effect; traditionally, these effects have been analyzed with econometric and engineering techniques, rather than from the perspective of geographical studies. The purpose of this research is to measure the spillover effects and the territorial cohesion of Infrastructure Regional Planning (PRI) for the Latin American metropolitan area of Concepción (MAC), Chile. To meet this purpose, locational and network efficiency indicators of spatial accessibility were calculated using network analysis in GIS. The results showed that the improvements differ according to the accessibility indicator employed; however, they generally showed benefits in consolidated urban centers and corridors near investment and industrial areas. In contrast, more distant and rural areas presented limited and irregular benefits.
Accessibility Indicators to Fresh Food: A Quantitative Insight from Concepción, Chile
(TAYLOR & FRANCIS INC, 2022) Rojas Quezada Carolina Alejandra; Widener, Michael J.; Carrasco, Juan Antonio; Meneses, Fernando; Rodríguez, Tiara; CEDEUS (Chile)
Accessibility is crucial to establishing and maintaining a nutritious and healthy diet. Although much of the literature on access to healthy food has focused on study areas in the Global North, the topic is of growing relevance to other regions across the globe. In Chile, where the prevalence of chronic diseases related to obesity and diet has increased, and over 50 percent of Chileans are considered overweight or obese, improving accessibility to healthy food has been an essential strat egy for improving health outcomes, including the food environment. In this article, we analyze walking accessibility from homes and workplaces to open street markets and supermarkets that sell fresh fruits and vegetables and consider the role of price in the Concepcion metropolitan area, the second most populated city in Chile. Results suggest that supermarkets and open street markets are distributed in a complementary way. Open street markets have a crucial role in facilitating access to more affordable products for peripheral and low-income areas. Findings also show workplaces increase accessibil ity in a way that is complementary to residential location
Assessment of the flood mitigation ecosystem service in a coastal wetland and potential impact of future urban development in Chile
(2022) Rojas, Octavio; Soto, Evelyn; Rojas Quezada, Carolina Alejandra; López, J. Javier; CEDEUS (Chile)
A worldwide increase in flooding due to climate change and population growth in exposed areas is expected, especially in coastal areas; therefore, nature-based solutions (NBS) for risk reduction are necessary to increase the resilience of cities, particularly in developing countries, which usually lack large budgets for structural measures but have natural areas such as wetlands that can be used as NBS. The flood mitigation ecosystem service of a coastal wetland in central Chile was analyzed. Using hydrological and topo-bathymetric data, two flood hazard scenarios were modeled: (i) S1 current and (ii) S2 projected, which was established based on land-use planning instruments and urban projects developed since 1954. Flood hazard maps for different return periods were obtained and indicators related to the mitigation potential of the wetland were calculated. It was proven that urban project development has intensified since 2000, mainly in the form of real estate development, with an increase in occupation of 50%, and the wetland area is projected to be further reduced by around one third, decreasing potential flood mitigation. Thus, for an extreme return period, in this case 500 years, the water volume stored by the wetland would decrease by more than 38% and the flooded area of the wetland by 30%, increasing flooding and vulnerability of the urban area, with various repercussions for surrounding neighborhoods and infrastructure. The number of people and homes affected would increase by around 6% and 8%, respectively, such that the affected land value would reach an additional US$55 million, which would be very detrimental in a city that has seen its natural spaces encroached upon by gray infrastructure. This research reaffirms the need to support the restoration and conservation of coastal wetlands under pressure from urban development in an area with a lack of green infrastructure planning.
Challenges and opportunities for drinking water treatment residuals (DWTRs) in metal-rich areas: an integrated approach
(2022) Briso, Alejandro; Vega, Alejandra; Molinos Senante, María; Pasten Gonzalez, Pablo Arturo; CEDEUS (Chile)
The physicochemistry and production rate of drinking water treatment residuals (DWTRs) depends on the raw water composition and the plant operational parameters. DWTRs usually contain Fe and/or Al oxyhydroxides, sand, clay, organic matter, and other compounds such as metal(oids), which are relevant in mining countries. This work proposes a simple approach to identify DWTRs reuse opportunities and threats, relevant for public policies in countries with diverse geochemical conditions. Raw water pollution indexes and compositions of DWTRs were estimated for Chile as a model case. About 23% of the raw drinking water sources had moderate or seriously contamination from high turbidity and metal(loid) pollution If the untapped reactivity of clean DWRTs was used to treat resources water in the same water company, the 73 and 64% of these companies would be able to treat water sources with As and Cu above the drinking water regulations, respectively. Integrating plant operational data and the hydrochemical characteristics of raw waters allows the prediction of DWTRs production, chemical composition, and reactivity, which is necessary to identify challenges and opportunities for DWTRs management.
Coastal Wetlands: Ecosystems Affected by Urbanization?
(2020) Rojas Quezada, Carolina Alejandra; Novoa, Vanessa; Rojas, Octavio; Ahumada-Rudolph, Ramón; Sáez, Katia; Fierro, Pablo; CEDEUS (Chile)
Coastal wetlands are ecosystems that provide multiple benefits to human settlements; nonetheless, they are seriously threatened due to both a lack of planning instruments and human activities associated mainly with urban growth. An understanding of their functioning and status is crucial for their protection and conservation. Two wetlands with different degrees of urbanization, Rocuant-Andalién (highly urbanized) and Tubul-Raqui (with little urbanization), were analyzed using temperature, salinity, dissolved oxygen, pH, turbidity, granulometry, fecal coliform, and macroinvertebrate assemblage variables in summer and winter. In both wetlands marked seasonality in salinity, temperature and sediment texture classification, regulated by oceanic influence and changes in the freshwater budget, was observed. In the Rocuant-Andalién wetland, the increases in pH, dissolved oxygen, gravel percentage, and coliform concentration were statistically significant. Urbanization generated negative impacts on macroinvertebrate assemblage structure that inhabit the wetlands; greater richness and abundance (8.5 times greater) were recorded in the Tubul-Raqui wetland than in the more urbanized wetland. The multivariate statistical analysis reflects the alteration of these complex systems.
Compact development and preferences for social mixing in location choices: results from revealed preferences in Santiago, Chile
(2021) Hurtubia González, Ricardo; Cox, Tomás; CEDEUS (Chile)
Even though densification and social mixing are declared objectives of many nowadays urban planning paradigms, their simultaneous implementation is usually questioned by different actors and is not frequent in practice. In a market economy, understanding potential demand for this class of development, from different types of households, is essential to define public policies oriented to achieve both compact development (CD) and social mixture. To understand the preferences of households and potential demand, we implement a location choice model based on a bid–rent framework and spatial latent classes (LC), using census data and location attributes. By using spatial LC, we do not impose exogenous definitions of which zones are perceived as CD or suburban, rendering a robust method to identify variation in preferences. We apply the model to Santiago de Chile, where social mixing in dense and well-located areas is being intensely discussed. We find strong differences in households' valuation of attributes between spatial classes. Results show that social mixing is more difficult in dense, well-connected areas than in suburban areas because higher-income households are more sensitive to the socioeconomic context of the location in compact areas. Besides showing evidence on household preferences and their implications for social-mixing policies, this paper also provides a proof of concept for the use of spatial LC (proposed in previous work by the authors), showing this is a robust methodology allowing to generate behavior-based classifications for urban areas. The paper also contributes methodologically, by deriving the elasticity formulation for bid-auction location choice models, which allows quantifying the importance of location attributes in location probability.
Copper entrapment and immobilization during cement hydration in concrete mixtures containing copper tailings
(2021) Vargas, Felipe; Alsina, Marco A.; Gaillard, Jean-François; Pasten Gonzalez, Pablo Arturo; López, Mauricio; CEDEUS (Chile)
The use of copper tailings as supplementary cementitious material can reduce the environmental impacts ofconcrete production and the mining industry. A key concern limiting its application is the potential leaching oftoxic metals from the cementitious matrix, especially copper. To analyze and reduce the risk of leaching, themechanisms by which copper is entrapped in the cementitious matrix were investigated, by combining micro-scopic and spectroscopic approaches. Decreasing the water-to-binder ratio was statistically relevant to reducecopper leaching. Scanning Electron Microscope micrographs allowed to spatially localize enriched copperclusters within the cementitious hydration products. In the early stages of the cementitious hydration (i.e., 24 h),no spatial correlation between copper and hydration products was found; however, after seven days, copper wasspatially associated with calcium silicate hydrates. Cu K-edge X-ray absorption near edge structure spectroscopyprovided insights into the chemical speciation of copper in the cementitious matrix. It showed that copper sulfideand oxide phases persisted, whereas the copper sulfate phases were prone to dissolution and reprecipitation ascupric hydroxides induced by the relatively high pH from calcium hydroxides formed during hydration. Pro-moting the formation of hydration products can further reduce copper leaching from the alkaline cementitiousmatrix. A better understanding of metal entrapment mechanisms could lead to new strategies that reduce themobility of toxic elements when using copper tailings, increasing their use as a replacement of cement. With thisknowledge, it is expected to answer if it is possible to improve the copper entrapment into the cementitiousmatrix and if there is a risk of leaching once is entrapped.
Designing and worlding: prototyping equivocal encounters
Hermansen Ulibarri, Pablo Ignacio; Tironi Rodo, Martin Carlos; CEDEUS (Chile)
To sustainably coexist with other ontologies, human beings must overcome the perception of being the center of the world. This article describes how a video log refuted the initial – anthropocentric – hypothesis explaining the breakdown of an experiment with Judy and Gombe, chimpanzees that inhabit the National Zoo of Chile. This shows that it is wrong to ascribe human affects and reactions to other ontologies, and also that there is a long way to go to apprehend, comprehend, and sustainable coexist with other ontologies in more-than-human ecosystems.
Elderly Walking Access to Street Markets in Chile: An Asset for Food Security in an Unequal Country
(2023) Rojas Quezada Carolina Alejandra; Castillo, Bryan; Villegas, Rodrigo; Vecchio, Giovanni; Steiniger, Stefan; Carrasco, Juan Antonio; CEDEUS (Chile)
Street markets can contribute to food security, since they are a source of fresh food and comparably inexpensive goods, being very relevant for low-income groups. Their relevance is even higher when considering older people, due to their often-constrained financial resources and possibilities to move. To assess the potential contribution of street markets to food security, this paper aims at evaluating to what extent older people have access to such a relevant asset. We consider the case of Chile, an ageing country with an unequal pension system, which makes it relevant for older people to access healthy and inexpensive food. We analyze what proportion of older people (i.e., people over 65) has walking access within 10 min to a street market—feria libre—in each Chilean region, with particular detail in the country’s four major urban areas. We compare the resulting accessibility maps with census data to identify neighborhoods with higher proportions of older people and examine their socio-economic conditions. Our findings show that while street markets are less accessible to older people in comparison to the general population, the inhabitants who can access them belong mainly to low-income groups. The results provide relevant insights to develop neighborhood-based policies for spreading and strengthening street markets, especially in low-income areas with insufficient levels of access to other relevant urban opportunities.
Employment and sustainability: the relation between precarious work and spatial inequality in the neoliberal city
(2022) Señoret Swinburn, Andrés; Ramírez Silva, María Inés; Rehner, Johannes; CEDEUS (Chile); Pontificia Universidad Católica de Chile
The creation of employment opportunities is a key factor to economic growth, but when pursuing sus tainable development, work arrangements must also be fair and stable. In contrast, precarious employ ment is a common and serious limitation to prospects for development and personal well being in Latin American cities. Discussing this phenomenon in the developing world requires considering the ongoing transformation of the neoliberal urban labour market, the commodity-driven economic struc ture, and questioning how such features relate to the likelihood of urban sustainable development. The present study addresses precarity in urban labour markets and subjective perceptions of stability and prospects and asks how marginalisation and fragmented urban spaces in a neoliberal context relate to the structural characteristics of precarious labour. This relationship between labour and space is anal ysed based on survey data from different types of neighbourhoods in Chile’s two largest metropolitan areas – Santiago and Concepción – using multilevel regression and ANOVA. Our study finds that precar ious employment and poor prospects replicate and reinforce typical territorial inequalities and thus con stitute a serious limitation for sustainable development. We conclude that the current labour market, the features of neoliberal extractivism, and weak formal social protection are obstructing urban development that is sustainable in terms of employment. Thus, the conceptual debate on sustainability and urban pol icy should focus more on the negative effects of precarious employment and its particular relation to spatial fragmentation in growing urban areas.
Fare evasion in public transport: How does it affect the optimal design and pricing?
(Elsevier Ltd, 2023) Ramos Guerrero, Raúl Alfonso; Silva Montalva, Hugo Emilio; CEDEUS (Chile)
© 2023 Elsevier LtdFare evasion produces significant revenue losses in public transport systems. Recent research has found that low service quality and high prices are important determinants of fare evasion. However, the economic literature that studies the optimal public transport provision has overlooked the phenomenon. We develop a demand model of horizontal differentiation to investigate how fare evasion affects the design and pricing of public transport that maximizes utilitarian social welfare. We show analytically that fare evasion can create incentives to reduce public transport prices and improve service quality, putting upward pressure on its subsidization. We perform numerical simulations and sensitivity analysis to quantify the impact of these incentives on the public transport provision. These simulations confirm that the incentive to reduce fare evasion can lead to an optimal design and price that requires subsidies.
Freedom of choice? Social and spatial disparities on combined housing and transport affordability
(2022) Tiznado Aitken, Ignacio Andrés; Lucas, Karen; Muñoz Abogabir, Juan Carlos; Hurtubia González, Ricardo; CEDEUS (Chile)
Housing and transport affordability (H + TA) analysis has been receiving increasing attention among academics and practitioners worldwide, particularly in Global North settings. These studies usually overlook spatial and socioeconomic distributional considerations that potentially underestimate the simultaneous impact of transport and housing costs on lower-income family budgets. Our work seeks to address these knowledge gaps by understanding and measuring H + TA, considering different types of households in Santiago, Chile. Combining income, housing, transport, and census data, we estimate H + TA costs using spatial clusters and probability distribution functions, analyzing the “degree of choice” that socially disadvantaged groups have given their financial constraints. The results show that families with children, the elderly, and immigrants are among the most limited in their choices. Most central and eastern sectors of the city which provide the highest density of work opportunities are out of reach for the three lowest-income deciles given the high combined costs of H + TA, being dependents on government benefits and/or social housing. Middle class, from the 4th to 6th income deciles, can choose from between 30% and 65% of all housing and transport combinations, but from less than 6% of those offered on the two clusters with the best transport and urban conditions. These findings bring into question current inter-sectoral policies to alleviate the “cost pressure” of Santiago's lower- and middle-income households.
Gender inequality, women's empowerment, and adolescent birth rates in 363 Latin American cities
(2023) Braverman-Bronstein, Ariela; Ortigoza, Ana F.; Vidaña-Pérez, Dèsirée; Barrientos-Gutiérrez, Tonatiuh; Baldovino-Chiquillo, Laura; Bilal, Usama; Friche, Amélia Augusta de Lima; Diez-Canseco, Francisco; Maslowsky, Julie; Vives Vergara, Alejandra; Diez Roux, Ana V.; CEDEUS (Chile)
Background: Gender inequality is high in Latin America (LA). Empowering girls and young women and reducing gender gaps has been proposed as a pathway to reduce adolescent pregnancy. We investigated the associations of urban measures of women's empowerment and gender inequality with adolescent birth rates (ABR) in 366 Latin American cities in nine countries. Methods: We created a gender inequality index (GII) and three Women Achievement scores reflecting domains of women's empowerment (employment, education, and health care access) using censuses, surveys, and political participation data at city and sub-city levels. We used 3-level negative binomial models (sub-city-city-countries) to assess the association between the GII and scores, with ABR while accounting for other city and sub-city characteristics. Results: We found within country heterogeneity in gender inequality and women's empowerment measures. The ABR was 4% higher for each 1 standard deviation (1-SD) higher GII (RR 1.04; 95%CI 1.01,1.06), 8% lower for each SD higher autonomy score (RR 0.92; 95%CI 0.86, 0.99), and 12% lower for each SD health care access score (RR 0.88; 95%CI 0.82,0.95) after adjustment for city level population size, population growth, homicide rates, and sub-city population educational attainment and living conditions scores. Conclusion: Our findings show the key role cities have in reducing ABR through the implementation of strategies that foster women's socioeconomic progress such as education, employment, and health care access.
Health protection among own account and platform workers during COVID19 in Chile. The PWR project
(2022) Ruiz, M. ; Vives Vergara, Alejandra; Alvarez, V.; Diaz, I.; Zaupa, A.; CEDEUS (Chile)
Background: In the last decades, non-standard employment has grown globally. Especially for own account workers (OAW), this implies the self-management of economic, health and other work-related risks. In the context of COVID19, this management was stressed by lockdowns and the novel health risks imposed by an unknown and highly contagious virus, demanding the incorporation of new knowledge and preventive actions. As part of a six-country multiple case qualitative study on non-standard workers (NSW), we explore their experiences and strategies deployed to protect their health while continuing to work. Methods: We performed 40 in-depth interviews to NSWs between October 2020 and February 2021, identified through the PWR online-survey and selected through an intentional sampling strategy according to levels of precarity (high-low), gender (male/female) and age (18-39/40-55). Interviews were analysed through abductive thematic analysis. Results: We observed a significant transfer to platform, Uber-like jobs in the delivery of goods during lockdown (n = 7). In the absence of institutional prevention programs and provision of protective equipment, OAWs (n = 13) refer the self-provision of COVID19 prevention to protect themselves and their families while continuing to work, deploying a series of strategies amidst limited understanding of both mode of transmission of the virus and actual effective preventive measures. This had serious consequences for them and their families, expressed in anguish, sense of lack of control, fear, and fragility in the face of a major health risk given their constant potential exposure to the virus, leading to both physical and mental health problems, as well as COVID19 infection. Conclusions: The substantial growth worldwide of gig delivery work during lockdowns magnified a pressing public health problem, critically requiring social security for gig and OAWs and the development of more equitable and accessible occupational health for all. Key messages: • Substantial growth worldwide of gig delivery work during lockdowns magnified a pressing public health problem.• Social security for gig and OAWs are critically required as well as the development of more equitable and accessible occupational health for all.
Indicadores de sustentabilidad urbana a escala local en Chile. Observatorio de Barrios Sustentables.
(2016) Avilés, David; Barton, Jonathan R.; D'alencon, Renato; Moris Iturrieta, Roberto; Ruiz, Juan Carlos; Salas, Roberto; Steiniger, Stefan; CEDEUS (Chile)
En este trabajo se discuten estas cuestiones y se presenta un estudio piloto cuyo objetivo es desarrollar indicadores para evaluar la sustentabilidad de los barrios residenciales en Chile, con la intención de transformarse en una herramienta de trabajo tanto para los vecinos de los barrios, como para actores externos que estén interesa-dos en intervenir de acuerdo con la realidad del país. Se elaboró una lista de 85 indicadores de sustentabilidad basada en una revisión de la literatura, las políticas chilenas y en reuniones de expertos. Los indicadores abarcan 10 áreas de sustentabilidad como seguridad, empleo e ingresos, educación, acceso y movilidad, etc. El trabajo incluye un estudio de 13 barrios ubicados en 6 ciudades chilenas: Copiapó, La Serena, Santiago, Concepción, Temuco y Valdivia. Además, se eligieron tres referencias, es decir, barrios modelos con un ingreso más alto o una ubicación central para poder explorar la gama completa de valores de indicador. El artículo describe finalmente cómo fueron seleccionados los indicadores y los barrios y se presenta una herramienta exploratoria de análisis de datos para compararlos.
Mapping coastal wetlands using satellite imagery and machine learning in a highly urbanized landscape
(2022) Munizaga, Juan; García, Mariano; Ureta, Fernando; Novoa, Vanessa; Rojas, Octavio; Rojas Quezada, Carolina Alejandra; CEDEUS (Chile)
Coastal wetlands areas are heterogeneous, highly dynamic areas with complex interactions between terrestrial and marine ecosystems, making them essential for the biosphere and the development of human activities. Remote sensing offers a robust and cost-efficient mean to monitor coastal landscapes. In this paper, we evaluate the potential of using high resolution satellite imagery to classify land cover in a coastal area in Concepción, Chile, using a machine learning (ML) approach. Two machine learning algorithms, Support Vector Machine (SVM) and Random Forest (RF), were evaluated using four different scenarios: (I) using original spectral bands; (II) incorporating spectral indices; (III) adding texture metrics derived from the grey-level covariance co-occurrence matrix (GLCM); and (IV) including topographic variables derived from a digital terrain model. Both methods stand out for their excellent results, reaching an average overall accuracy of 88% for support vector machine and 90% for random forest. However, it is statistically shown that random forest performs better on this type of landscape. Furthermore, incorporating Digital Terrain Model (DTM)-derived metrics and texture measures was critical for the substantial improvement of SVM and RF. Although DTM did not increase the accuracy in SVM, this study makes a methodological contribution to the monitoring and mapping of water bodies’ landscapes in coastal cities with weak governance and data scarcity in coastal management.
Optimal location of bike-sharing stations: A built environment and accessibility approach
(2022) Mix Vidal, Richard Alexander; Hurtubia González, Ricardo; Raveau Feliú, Sebastián; CEDEUS (Chile)
Bike-sharing systems (BSS) have arisen worldwide as an attractive and sustainable travel alternative. As these systems have shown positive effects in reducing congestion and emissions, it is relevant to properly analyze their potential implementation in different contexts. Evidence has shown that BSS can only provide benefits when their network is adequately designed, in order to capture ridership and generate demand. This study proposes an integrated approach to model the demand of bike-sharing trips and the optimal location of stations in the system, based on built environment and accessibility-based variables. The methodology consists of two steps. On the first step, trip generation models are estimated through multiple regressions for different types of trips and periods of the week. On the second step, maximum demand coverage models are developed to allocate the BSS stations, according to the trip generation models and to different proposed scenarios. To test the proposed methodology, information from the BSS of Santiago de Chile is used. Results suggest a relationship between the built environment and the use of public bicycles, with a main effect of residential and office land uses, and the presence of long bicycle lanes near the stations. In addition, the presence of endogeneity, associated with the location of BSS stations and BSS demand generation, is confirmed and controlled using accessibility variables. As for the optimal location models, their outcomes differ significantly from the observed spatial distribution of stations in Santiago, with higher density in central areas and along corridors with cycling infrastructure. The forecasted demand level for the optimal distribution of stations is 64% higher than the observed demand. This study confirms the benefit of an integrated modelling of the trip generation and the station location to foster higher public bicycle usage, a relevant point for BSS decision planning and the promotion of a more sustainable mobility.

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