Lya Sierra

Dr. Lya Sierra

orcid

Research Focus & Metrics

Academic Career Length

18Years (2009-Present)

(Calculated once Scilit publication data is synced: current year − year of first publication + 1)

Representative Publications

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11 July 2014 in Applied Economics
Verified
Journal Article
Closed access
PPPilar Poncela
Pilar Poncela
ESEva Senra
Eva Senra
LSLya Sierra
Lya Sierra
The purpose of this article is to improve the empirical evidence on commodity prices in various dimensions. First, we attempt to identify the extent of comovements in 44 monthly nonenergy commodity price series in order to ascertain whether the increase in comovement is a recent term phenomenon. Second, we attempt to determine the role of uncertainty in determining comovements among nonenergy prices in the short run. We diagnose the overall comovement using a dynamic factor model estimated by principal components. A factor-augmented vector autoregressive approach is used to assess the relationship of fundamentals, financial and uncertainty variables with the comovement in commodity prices. We find a greater synchronization among raw materials since December 2003. Since that date, uncertainty has played an important role in determining short-run fluctuations in nonenergy raw material prices.The purpose of this article is to improve the empirical evidence on commodity prices in various dimensions. First, we attempt to identify the extent of comovements in 44 monthly nonenergy commodity price series in order to ascertain whether the increase in comovement is a recent term phenomenon. Second, we attempt to determine the role of uncertainty in determining comovements among nonenergy prices in the short run. We diagnose the overall comovement using a dynamic factor model estimated by principal components. A factor-augmented vector autoregressive approach is used to assess the relationship of fundamentals, financial and uncertainty variables with the comovement in commodity prices. We find a greater synchronization among raw materials since December 2003. Since that date, uncertainty has played an important role in determining short-run fluctuations in nonenergy raw material prices

7 July 2022 in Sustainability
Verified
Journal Article
Open access
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LDLida Díaz-Pinzón
Lida Díaz-Pinzón
LSLya Sierra
Lya Sierra
FTFrancesc Trillas
Francesc Trillas
Urban growth has impacted natural ecosystems such as wetlands. This situation destabilizes the beneficial contributions of nature, generating a socioeconomic effect. There is a need to quantify the benefits of wetlands in developing countries and urban areas, where the growth of cities is fastest. This is the first valuation study of urban and peri-urban wetlands in Colombia. The methodology includes a benefit transfer (BT) method with a geographical information system (GIS) and an exploratory governance analysis. Because there are few studies on the economic valuation of urban wetlands in Latin America, we present a methodology of interest, which can be easily replicated in other cities of this subcontinent. Based on an economic approach, our results find that 76% of the total value of wetlands is provided by ecosystem services (ES) of existence and legacy value, followed by maintenance of the life cycle of migratory species and water supply. Urban areas are identified where users benefit more than areas where the population exerts greater pressure on wetlands. Weak governance is due to the disarticulation between regulation, land-use planning, and the social-ecological system. This research contributes to urban wetland management policies, as well as to sustainable solutions in cities.


10 January 2024 in International Journal of the Commons
Verified
Journal Article
Open access
PDF file
LDLida Díaz-Pinzón
Lida Díaz-Pinzón
LSLya Sierra
Lya Sierra
FTFrancesc Trillas
Francesc Trillas
JVJoan Miquel Verd
Joan Miquel Verd
The social-ecological system of wetlands supports biodiversity and enhances the mental well-being of urban inhabitants. However, wetlands in Latin America face pressures from urban expansion, agriculture, governance conflicts, and poorly enforced regulations driven by economic activities, resulting in biodiversity loss and diminished ecosystem services. This study applies the social-ecological system framework to identify ecosystem services and evaluate factors influencing collective actions and governance effectiveness for urban and peri-urban wetlands. The case study is based in Cali, Colombia, using 33 semi-structured interviews, document analysis, and field visits. We find that facilitators such as leadership, networking, social capital, and community-based rules drive positive outcomes, enhancing ecosystem services. In contrast, barriers to collective action in wetland governance include low resource dependence, diverse actors, exclusion of groups, large resource size, pollution, conflicts, and property-rights issues, leading to ecosystem degradation. Additionally, our research shows how ecosystem services are influenced by environmental conflicts, property-rights systems, and community-led initiatives. Collaboration between communities and public agencies is crucial, enhancing local governance efficiency and ecosystem services.

21 May 2024 in Bulletin of Economic Research
Verified
Journal Article
Open access
JOJohanna Marcela Orozco-Castañeda
Johanna Marcela Orozco-Castañeda
LSLya Sierra
Lya Sierra
PVPavel Vidal
Pavel Vidal
The COVID‐19 pandemic ushered in unprecedented social and economic conditions, alongside unexpected policy responses, challenging the effectiveness of traditional labor market forecasting approaches. This article presents a novel approach that integrates macroeconomic variables, traditional labor market metrics, and Google search data to develop a machine learning‐based indicator for the Colombian labor market. We employ support vector machine for regression and neural networks models to forecast monthly employment and unemployment rates, explicitly focusing on the third wave of COVID‐19 in the first half of 2021. Our study's findings reveal that the proposed models outperform the autoregressive benchmark regarding forecast accuracy, demonstrating a rapid adaptation to labor market shifts.

14 August 2020 in Revista Finanzas y política económica
Verified
Journal Article
Open access
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CCCarlos David Cardona-Arenas
Carlos David Cardona-Arenas
LSLya Sierra
Lya Sierra
Este artículo analiza el impacto de la política monetaria en la tasa de desempleo no aceleradora de la inflación (NAIRU), o equilibrio de los mercados de trabajo para los países que pertenecen a la Alianza del Pacífico (Chile, Colombia, Perú y México). Los movimientos NAIRU se determinan para cada país. Además, se estiman modelos de vectores autorregresivos para evaluar el impacto de la política monetaria en el mercado laboral de cada uno de los países de la Alianza del Pacífico. Los resultados muestran que la política monetaria impacta la NAIRU de Chile, Colombia y Perú, mientras que los shocks de tal política no tienen repercusión significativa en la NAIRU de México.