scispace - formally typeset
Search or ask a question

Showing papers by "University of Los Andes published in 2022"


Journal ArticleDOI
TL;DR: Decision Support Systems for sustainable urban drainage systems (DSS-DSS) as discussed by the authors are a valuable aid for SUDS widespread adoption, which systematize the decision-making criteria and eliminate the bias inherent to expert judgment, abridging the technical aspect of SUDS for non-technical users and decision-makers.

27 citations


Journal ArticleDOI
TL;DR: In this paper, the authors presented Bayesian model updating and identifiability analysis of nonlinear finite element (FE) models with a specific testbed civil structure, Pine Flat concrete gravity dam, as illustration example.

14 citations


Journal ArticleDOI
TL;DR: In this paper , the authors examine, for the first time in a low- or middle-income country, which mechanisms best explain the disproportionate impact of the virus on the poor, and they show that total infections and inequalities in infections are largely driven by inequalities in the ability to work remotely and in within-home secondary attack rates.
Abstract: Across the world, the COVID-19 pandemic has disproportionately affected economically disadvantaged groups. This differential impact has numerous possible explanations, each with significantly different policy implications. We examine, for the first time in a low- or middle-income country, which mechanisms best explain the disproportionate impact of the virus on the poor. Combining an epidemiological model with rich data from Bogotá, Colombia, we show that total infections and inequalities in infections are largely driven by inequalities in the ability to work remotely and in within-home secondary attack rates. Inequalities in isolation behavior are less important but non-negligible, while access to testing and contract-tracing plays practically no role because it is too slow to contain the virus. Interventions that mitigate transmission are often more effective when targeted on socioeconomically disadvantaged groups.

12 citations


Journal ArticleDOI
TL;DR: In this article , a global synthesis of forest degradation or deforestation using 48 studies published in peer-reviewed journals that use dung beetles as indicators given their sensitivity to anthropogenic disturbance and their relevance in performing essential ecological functions in terrestrial ecosystems.
Abstract: Because of continuing degradation or deforestation in areas of undisturbed primary forest, there is a need to study the relative merit of strategies that mitigate their impacts on biodiversity and associated ecological functionality. Here, we provide a global synthesis of forest degradation or deforestation using 48 studies published in peer-reviewed journals that use dung beetles as indicators given their sensitivity to anthropogenic disturbance and their relevance in performing essential ecological functions in terrestrial ecosystems. We evaluated forest cover associated with undisturbed primary forest degradation (i.e. degraded primary forest) and undisturbed primary forest deforestation (i.e. secondary forest, forestry plantations and forestry restoration implementation) on species richness, total abundance, biomass, functional groups' presence and ecological functions provided by dung beetles. Additionally, we determined whether if dung beetle responses to forest disturbances were geographically dependent. We found lower diversity and a decrease in ecological functions associated with all classes of disturbance in primary forest. However, the effects were less severe in the case of forest degradation compared to complete deforestation with natural regeneration of secondary forest, development of forest plantations or active forest restoration by planting indigenous trees. The Neotropical and Oriental regions are particularly vulnerable, given the elevated rates of undisturbed primary forest deforestation and its negative impact on their assemblages' diversity and ecological functions. Synthesis and applications. Our results show that efforts for the conservation of remaining undisturbed primary forests need to be prioritized, especially in tropical latitudes. However, in regions where primary forest conservation is not feasible, logging management programs in degraded primary forest may have a potential role in reducing negative impacts for dung beetle diversity and ecological functions. Moreover, we conclude that despite the negative effect of primary forest deforestation and implementation of secondary forest, forestry plantation and forestry restoration, they can be useful for partial recovery of diversity and ecological functions performed by dung beetles in areas lacking any primary forest (undisturbed or degraded) vegetation cover.

11 citations


Journal ArticleDOI
01 Jan 2022
TL;DR: In this paper, a continuous-time evolutionary game dynamics for generalized Nash equilibrium seeking in equality-constrained population games is proposed, and sufficient conditions to guarantee the asymptotic stability, nonemptiness, compactness, and optimality of the proposed dynamics for certain population games are provided.
Abstract: This letter proposes a novel form of continuous-time evolutionary game dynamics for generalized Nash equilibrium seeking in equality-constrained population games. Using Lyapunov stability theory and duality theory, we provide sufficient conditions to guarantee the asymptotic stability, non-emptiness, compactness, and optimality of the equilibria set of the proposed dynamics for certain population games. Moreover, we illustrate our theoretical developments through a numerical simulation of an equality-constrained congestion game.

11 citations


Journal ArticleDOI
TL;DR: In this article, the authors studied the ex ante motivational effect of a nationwide merit and need-based scholarship in Colombia, which granted full scholarships to low-income students at high-quality universities.

9 citations


Journal ArticleDOI
TL;DR: In this article, the role of hydroxyl and epoxy bridges in room-temperature ferromagnetism of pyrolytic graphene oxide nanoplatelets (GOs) was investigated.

9 citations


Journal ArticleDOI
TL;DR: In this article , the authors describe and evaluate with a cluster-Randomized Controlled Trial an intervention designed to improve the quality of child stimulation within the context of an existing parenting program in Colombia, known as FAMI.
Abstract: Abstract Early childhood development is becoming the focus of policy worldwide. However, the evidence on the effectiveness of scalable models is scant, particularly when it comes to infants in developing countries. In this paper, we describe and evaluate with a cluster-Randomized Controlled Trial an intervention designed to improve the quality of child stimulation within the context of an existing parenting program in Colombia, known as FAMI. The intervention improved children’s development by 0.16 of a standard deviation (SD) and children’s nutritional status, as reflected in a reduction of 5.8 percentage points of children whose height-for-age is below -1 SD.

9 citations


Journal ArticleDOI
TL;DR: In this paper, the authors examined the associations of family engagement in home learning activities and in early childhood care and education centers (ECCE; e.g., attending meetings or workshops, helping inside the classroom) with young children's emergent literacy and numeracy, social-emotional functioning, motor development, and executive functions, as measured through direct assessment.

7 citations


Journal ArticleDOI
TL;DR: A novel high-throughput shotgun DNA sequencing approach applying masked reference libraries was developed and used for authentication and abundance calculations of fish species in mixed samples and demonstrated that both DNA and protein-based approaches can be used to efficiently tackle current challenges in feed and food authentication analyses.

7 citations


Journal ArticleDOI
TL;DR: In this paper, a family of surveys was designed as a part of an international initiative that congregates researchers from 12 countries to investigate the relationship between various software development activities and technical debt.

Journal ArticleDOI
TL;DR: In this article, the authors present the current challenges in emulsified product design and current trends and opportunities in this field, emphasizing the need for new indicators for customer requirements to link current market trends (e.g., consumer demand for green products) to the design of emulsification products.
Abstract: The chemical industry has experienced a paradigm shift from the production of bulk commodities towards formulated and specialized products such as emulsified products. This paradigm shift represents a significant challenge for emulsified product design due to the lack of understanding of these systems and low-fidelity predictive models. This review presents the current challenges in emulsified products design and current trends and opportunities in this field. This work emphasizes the need for new indicators for customer requirements to link current market trends (e.g., consumer demand for green products) to the design of emulsified products. This review also provides information concerning approaches and tools that could significantly improve the design process of emulsified products such as multiscale modeling and Process Intensification.

Journal ArticleDOI
TL;DR: In this paper, a maximum likelihood estimation algorithm for a linear dynamic system driven by an exogenous input signal, with non-minimum-phase noise transfer function and a Gaussian mixture noise is developed.

Journal ArticleDOI
TL;DR: In this article, a 3D printed β-TCP scaffolds were augmented with Ag ions to facilitate antibacterial effects while promoting osteoblast adhesion and proliferation, and they were evaluated using X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma mass spectroscope (ICP-MS) to verify the presence of Ag and phosphate (PO4 ) groups.
Abstract: Hypothesis Injuries requiring resection of tissue followed by autogenous bone transfer may be prone to infection by Staphylococcus aureus, impeding recovery and increasing medical costs. For critical sized defects, the common approach to reconstruction is a tissue transfer procedure but is subject to limitations (e.g., donor site morbidity, cost, operating time). Utilizing beta tricalcium phosphate (β-TCP) as bone grafting material augmented with silver (Ag), a custom graft may be 3D printed to overcome limitations and minimize potential infections. Experiments Scaffolds were 3D printed and augmented with Ag by external attack on the surface by silver nitrate (AgNO3 ) at varying concentrations (0.1, 1.0, 10% wt/wt of scaffold). The augmented scaffolds were evaluated utilizing X-ray diffraction (XRD), Fourier transform infrared spectroscopy (FTIR), and inductively coupled plasma mass spectroscopy (ICP-MS) to verify the presence of Ag and phosphate (PO4 ) groups followed by electron microscopy, thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC) to gather information of chemical and physical properties. Preliminary biocompatibility and bactericidal capacity of the scaffolds were tested using human osteoprogenitor (hOP) cells and methicillin-sensitive S. aureus strain, respectively. Results XRD, FTIR, ICP-MS, TGA, and DSC confirmed presence of Ag and PO4 groups, whereas electron microscopy showed a decrease in Ca and an increase in Ag ions, decreasing Ca/P ratio with increasing surfactant concentrations. PrestoBlue assays yielded an increase in fluorescence cell counts among experimental groups with lower concentrations of Ag characterized by their characteristic trapezoidal shape whereas cytotoxicity was observed at higher concentrations. Similar observations were made with alkaline phosphatase assays. Antimicrobial evaluation showed reduced colony-forming units (CFU) among all experimental groups when compared to 100% β-TCP. β-TCP scaffolds augmented with Ag ions facilitate antibacterial effects while promoting osteoblast adhesion and proliferation.

Journal ArticleDOI
TL;DR: In this paper, a semi-nonparametric approach was proposed to analyze the risk of crypto assets through a semidefinite-parameter approach, discussing its theoretical advantages and testing its performance compared to parametric approaches in terms of backtesting techniques and different risk measures.

Journal ArticleDOI
TL;DR: In this article , a multi-layer perceptron network with backward propagation was used to model non-linear multivariate systems for the prediction of operating and peak pressure drop in conical spouted beds.

Journal ArticleDOI
TL;DR: A detailed re-description of the holotype of the pliosaurid sauropterygian Kronosaurus boyacensis was provided in this paper , and a new genus, Monquirasaurus, was proposed.

Journal ArticleDOI
TL;DR: In this article , the authors reviewed road impacts on 36 apex predator species and assessed their risk from current roads based on road exposure and species vulnerability, and proposed a widely applicable method to assess the potential impact of future roads on apex predators.
Abstract: The global expansion of road networks threatens apex predator conservation and ecosystem functioning. This occurs through wildlife-vehicle collisions, habitat loss and fragmentation, reduced genetic connectivity and increased poaching. We reviewed road impacts on 36 apex predator species and assessed their risk from current roads based on road exposure and species vulnerability. Our findings reveal all apex predators are exposed to road impacts. Eight of the ten species with the highest risk occur in Asia, although other high-risk species are present in the Americas, Africa and Europe. The sloth bear suffers the highest risk of all apex predators, followed by the tiger and dhole. Based on species risk from roads, we propose a widely applicable method to assess the potential impact of future roads on apex predators. We applied this method to proposed road developments in three areas: the Brazilian Amazon, Africa, and Nepal, to locate high-impact road segments. Roughly 500 protected areas will be intersected by these roads, threatening core apex predator habitats. We advocate the need for rigorous road development planning to apply effective mitigation measures as an urgent priority and to avoid construction in wilderness areas and predator strongholds.

Journal ArticleDOI
TL;DR: In this paper , the authors compared three machine learning methods to classify VUS as Pathogenic or No pathogenic, implementing a Random Forest (RF), a Support Vector Machine (SVM), and a Multilayer Perceptron.
Abstract: The growing use of next-generation sequencing technologies on genetic diagnosis has produced an exponential increase in the number of variants of uncertain significance (VUS). In this manuscript, we compare three machine learning methods to classify VUS as Pathogenic or No pathogenic, implementing a Random Forest (RF), a Support Vector Machine (SVM), and a Multilayer Perceptron. To train the models, we extracted high-quality variants from ClinVar that were previously classified as VUS. For each variant, we retrieved nine conservation scores, the loss-of-function tool, and allele frequencies. For the RF and SVM models, hyperparameters were tuned using cross-validation with a grid search. The three models were tested on a nonoverlapping set of variants that had been classified as VUS over the last 3 years, but had been reclassified in August 2020. The three models yielded superior accuracy on this set compared to the benchmarked tools. The RF-based model yielded the best performance across different variant types and was used to create VusPrize, an open-source software tool for prioritization of VUS. We believe that our model can improve the process of genetic diagnosis in research and clinical settings.

Journal ArticleDOI
01 May 2022
TL;DR: In this paper , the authors propose an extension of the pulse algorithm, an exact method based on a recursive search that combines various pruning strategies to avoid complete exploration of the solution space.
Abstract: The Least Expected Travel-time Path on Stochastic and Time-Dependent networks (LETP-STD) is the problem of finding, for a given departure time, the path between an origin and a destination that guarantees the minimum expected travel time. The difficulty in solving this problem arises from the nonlinear objective function and the fact that Bellman’s principle of optimality does not hold. To tackle the LETP-STD, we propose an extension of the pulse algorithm, an exact method based on a recursive search that combines various pruning strategies to avoid complete exploration of the solution space. To accelerate our solution approach, we adapt several strategies that have proved their effectiveness in the deterministic context to the time-dependent stochastic domain, including a bidirectional adjustable search, an effective preprocessing method to remove nodes that are not part of the optimal solution, a lower bound on the objective function, and an upper-bound update procedure that joins the most promising paths. Finally, we derive the theoretical and empirical time complexity expressions of the algorithm. Experiments over a set of real-world transportation networks reveal that the algorithm compares favorably against the state-of-the-art methods.

Journal ArticleDOI
TL;DR: In this article , the authors studied the ex ante motivational effect of a nationwide merit and need-based scholarship in Colombia, which granted full scholarships to low-income students at high-quality universities.

Journal ArticleDOI
TL;DR: In this paper, the authors reconstructed a profile of peptides from whey hydrolysates with two enzymes and different processing conditions, and developed an ensemble machine learning predictor to classify peptides obtained from protein hydrolysis.


Journal ArticleDOI
TL;DR: This paper evaluated the impact of a financial education program consisting of three different learning tools, for children (6-18) in Bogota, Colombia, in 2018, and found several heterogeneous effects among the types of schools and grades.

DissertationDOI
26 Jul 2022
TL;DR: In this article , a revisión del material bibliográfico disponible for construir un estado del arte, de economía campesina, and sistemas de producción, for tratar de entender por qué estas unidades de produccionón se consideran estratégicas for persistir in el sector arrocero.
Abstract: Este estudio presenta los resultados de una investigación cuyo propósito principal fue la caracterización socioeconómica de productores de arroz de economía campesina y de sus unidades de producción, tomando como fuente principal de información los microdatos del Censo Nacional Agropecuario (CNA) 2014, para tratar de entender por qué estas unidades de producción se consideran estratégicas para persistir en el sector arrocero. Para alcanzar dicho propósito, se adelantó una revisión del material bibliográfico disponible para construir un estado del arte, de economía campesina y sistemas de producción, y para actualizar la revisión conceptual. Posteriormente, y como parte del trabajo estadístico, se seleccionaron y se caracterizaron las unidades de producción de arroz de economía campesina, y se finalizó con el análisis de las estrategias de permanencia, seleccionando tres grupos de productores de arroz de economía campesina. Para la selección de las unidades de producción de arroz de economía campesina se tuvo en cuenta los siguientes cuatro criterios: (1) predominio de la actividad agropecuaria, (2) uso predominante de la mano de obra familiar o comunitaria, (3) extensión máxima de la unidad productiva equivalente a una UAF,y (4) residir o vivir dentro de un perímetro funcional a la finca, o territorio colectivo, del cual se derivan sus medios de vida. Entre las características más importantes que explican la permanencia de las unidades productivas de arroz de economía campesina en el sector arrocero se encontró el alto grado de contribución de mano de obra familiar en la unidad productiva, el tipo de tenencia propia y colectiva de la tierra, así como una gran diversidad en la producción agropecuaria, relacionada a su vez con un elevado autoconsumo por parte de las familias de los productores.

Journal ArticleDOI
TL;DR: In this paper, the authors analyzed the relationship between mining and poverty in rural Colombia and found that mining with titles is not correlated with poverty levels, while mining without titles tends to increase poverty in the same municipality.

Journal ArticleDOI
01 Mar 2022
TL;DR: In this paper , the authors use three implementation techniques for context-oriented programming languages to assess their appropriateness to foster self-adaptive systems, and evaluate each of these approaches by assessing their modularity and complexity when defining adaptations, and by comparing their run time performance on a simple benchmark.
Abstract: The context-oriented programming paradigm is designed to enable self-adaptation, or dynamic behavior modification of software systems, in response to changes in their surrounding environment. Contextoriented programming offers an adaptation model, from a programming language perspective, that maintains a clean modularisation between the application and adaptation logic, as well as between the components providing adaptations. We use three implementation techniques for context-oriented programming languages to assess their appropriateness to foster self-adaptive systems. These approaches take advantage of the capabilities offered by the host programming language to realize self-adaptation as proposed by context-oriented languages. We evaluate each of these approaches by assessing their modularity and complexity when defining adaptations, and by comparing their run-time performance on a simple benchmark. Our results show a higher modularity than that for common architecture based self-adaptive systems, while maintaining comparable performance. We conclude that context-oriented programming is an appropriate paradigm to realize self-adaptation.

Journal ArticleDOI
TL;DR: In this paper , a stimuli-responsive hydrogel based on chitosan methacrylate (ChiMA), porcine small intestine submucosa methacelate (SISMA), and doxorubicin-functionalized reduced graphene oxide (rGO-DOX) was developed to eliminate microtumor residues from surgically resected melanoma through the coupled effect of NIR light-induced photothermal therapy and heat-induced DOXORUBicin release.
Abstract: Melanoma is an aggressive type of skin cancer that accounts for over 75% of skin cancer deaths despite comprising less than 5% of all skin cancers. Despite promising improvements in surgical approaches for melanoma resection, the survival of undetectable microtumor residues has remained a concern. As a result, hyperthermia- and drug-based therapies have grown as attractive techniques to target and treat cancer. In this work, we aim to develop a stimuli-responsive hydrogel based on chitosan methacrylate (ChiMA), porcine small intestine submucosa methacrylate (SISMA), and doxorubicin-functionalized reduced graphene oxide (rGO-DOX) that eliminates microtumor residues from surgically resected melanoma through the coupled effect of NIR light-induced photothermal therapy and heat-induced doxorubicin release. Furthermore, we developed an in silico model to optimize heat and mass transport and evaluate the proposed chemo/photothermal therapy in vitro over melanoma cell cultures.

Journal ArticleDOI
TL;DR: In this paper , the authors used density functional theory (DFT) calculations to develop novel adsorbents for removing mercury by investigating the adsorption of Hg0 onto silicon carbide (SiC) monolayers.

Journal ArticleDOI
TL;DR: In this paper , the authors proposed an optimal water flooding management methodology for setting the producer and injector wells conditions to maximize the net present value (NPV) of an oil field.