Preprints Académicos

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Trabajos académicos difundidos antes o en paralelo a publicación formal con revisión de pares. Cada documento lleva la etiqueta PREPRINT.

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1er Congreso Latinoamericano de Psicoterapia Familiar Sistémica en Bolivia.
(Universidad Católica Boliviana "San Pablo". Departamento de Psicología., 2021) Pinto Tapia, Bismarck
Del 13 al 15 de octubre del 2016 se llevó a cabo en la Universidad Católica Boliviana “San Pablo” (UCB) en la ciudad de La Paz el 1er CONGRESO LATINOAMERICANO DE PSICOTERAPIA FAMILIAR SISTÉMICA EN BOLIVIA: “Construyendo un modelo terapéutico latinoamericano” con la par ticipación de psicoterapeutas sistémicos bolivianos y latinoamericanos, ade más de renombrados psicólogos interesados en la epistemología y la ética de la psicoterapia. La terapia familiar sistémica es una escuela de psicología aplicada a la familia que pretende aliviar el sufrimiento de sus miembros a través de técnicas desarrolla das desde la teoría general de sistemas, la teoría matemática de la información, la cibernética y la teoría de los juegos, vinculadas con las teorías psicológicas. Se ha comprobado la eficacia y eficiencia de esta terapia en distintas latitudes, sin embargo recién se está evaluando su pertinencia en nuestro continente. Los resultados han mostrado la importancia de revisar los parámetros epistemológi cos y prácticos de sus modelos. De ahí que en varios países latinoamericanos se vienen formulando revisiones del enfoque sistémico para aplicarlo en las familias latinoamericanas.
6D-ViCuT: Six Degree-of-Freedom Visual Cuboid Tracking Dataset for Manual Packing of Cargo in Warehouses
(RELX Group (Netherlands), 2023) Guillermo Alberto Camacho Muñoz; Juan Martínez-Franco; Sandra Esperanza Nope-Rodríguez; Humberto Loaiza Correa; Sebastián Gil-Parga; David Álvarez‐Martínez
A 10 m vertical displacement on the Romanian Black Sea coast during modern history
(2024) Virgil Drăgușin; Nicolaie Alexandru; Mihai Caminschi; F. Chitea; Vasile Ersek; Alina Floroiu; Liviu Giosan; Georgiana Alexandra Grigore; Diana Hanganu; Maria Ilie
Abstract. Sea level reconstructions in the Black Sea basin and elsewhere rely on the identification of sea level markers and on the understanding of their post-genetic vertical movements. We present here evidence of a fast, bi-directional vertical displacement on the western Black Sea shore at Mangalia, Romania. We argue that an area situated near the shoreline was submerged 4 meters, subsequently filled with marine silts and sands, then uplifted by 10 m, where it currently stands. Radiocarbon dating of several types of materials from the infill, as well as archaeological evidence, indicate that this displacement occurred during the 18th–19th century. While performing radiocarbon dating, we found that near shore clam shells can show a 14C reservoir age offset of ~900 years probably due to the hard water effect, adding more complications to the already problematic dating of Black Sea coastal sediments. Our findings offer strong evidence of short-term, local tectonic movements that should be considered when past sea levels are calculated, while at the same time serve a warning for urban and marine development planners.
A Trypanosoma cruzi Antigen and Epitope Atlas: deep characterization of antibody specificities in Chagas Disease patients across the Americas
(2022) Alejandro D. Ricci; Leonel Bracco; Janine M. Ramsey; Melissa S. Nolan; Mary K. Lynn; Jaime Altcheh; Griselda Ballering; Faustino Torrico; Norival Kesper; Juan Carlos Villar
ABSTRACT During an infection, the immune system produces pathogen-specific antibodies. With time, these antibody repertoires become specific to the history of infections and represent a rich source of diagnostic markers. However, the specificities of these antibodies are mostly unknown. Here, using high-density peptide arrays we examined the specificities of human antibody repertoires of Chagas disease patients. Chagas disease is a neglected disease caused by Trypanosoma cruzi, a protozoan parasite that evades immune mediated elimination and mounts long-lasting chronic infections. We describe here the first proteome-wide search for antigens and epitopes and their seroprevalence at the individual level and across human populations. In a first discovery screening of 2.84 million short peptides spanning two T. cruzi proteomes we found 3,868 distinct antigenic protein regions. Further analysis of repertoires from 71 individuals provided information on their seroprevalence and showed a large fraction of private epitopes of low seroprevalence (<20%), and novel high seroprevalence antigens. Using single-residue mutagenesis we found the core epitopes required for antibody binding for 232 of these epitopes. These datasets enable the study of the Chagas antibody repertoire at an unprecedented depth and granularity, while also providing a rich source of novel serological biomarkers. IMPACT STATEMENT This work reveals the diversity and extent of antibody specificities in Chagas Disease and provides a wealth of well-defined antigenic markers for diagnosis and development of serological applications for this neglected infectious disease.
A Trypanosoma cruzi Trans-Sialidase Peptide Demonstrates High Serological Prevalence Among Infected Populations Across Endemic Regions of Latin America
(2025) Hannah Kortbawi; Ryan Marczak; Jayant V. Rajan; Nash L Bulaong; John E. Pak; Wesley Wu; Grace Wang; Anthea Mitchell; Aditi Saxena; Anshu Maheswari
Infection by Trypanosoma cruzi, the agent of Chagas disease, can irreparably damage the cardiac and gastrointestinal systems during decades of parasite persistence and related inflammation in these tissues. Diagnosis of chronic disease requires confirmation by multiple serological assays due to the imperfect performance of existing clinical tests. Current serology tests utilize antigens discovered over three decades ago with small specimen sets predominantly from South America, and lower test performance has been observed in patients who acquired T. cruzi infection in Central America and Mexico. Here, we attempt to address this gap by evaluating antibody responses against the entire T. cruzi proteome with phage display immunoprecipitation sequencing comprised of 228,127 47-amino acid peptides. We utilized diverse specimen sets from Mexico, Central America and South America, as well as different stages of cardiac disease severity, from 185 cases and 143 controls. We identified over 1,300 antigenic T. cruzi peptides derived from 961 proteins between specimen sets. A total of 67 peptides were reactive in 70% of samples across all regions, and 3 peptide epitopes were enriched in ≥90% of seropositive samples. Of these three, only one antigen, belonging to the trans-sialidase family, has not previously been described as a diagnostic target. Orthogonal validation of this peptide demonstrated increased antibody reactivity for infections originating from Central America. Overall, this study provides proteome-wide identification of seroreactive T. cruzi peptides across a large cohort spanning multiple endemic areas and identified a novel trans-sialidase peptide antigen (TS-2.23) with significant potential for translation into diagnostic serological assays.
A Characterization of Strongly Dependent Ordered Abelian Groups
(National University of Colombia, 2018) Alfred Dolich; John Goodrick
We characterize all ordered Abelian groups whose ﬁrst-order theory in the language {+, <, 0} is strongly dependent. The main result of this note was obtained independently by Halevi and Hasson [7] and Farré [5].
A CONSTANT SELF-CONSISTENT SCATTERING LIFETIME IN SUPERCONDUCTING STRONTIUM RUTHENATE
(2024) Pedro Contreras
In this numerical work, we find a self-consistent constant scattering superconducting lifetime for two different values of the disorder parameters, the inverse atomic strength, and the stoichiometric impurity in the triplet paired unconventional super-conductor strontium ruthenate. This finding is relevant for experimentalists given that the expressions for the ultrasound attenuation and the electronic thermal conductivity depend on the superconducting scattering lifetime, and a constant lifetime fits well nonequilibrium experimental data. Henceforth, this work helps experimentalists in their interpretation of the acquired data. Additionally, we encountered tiny imaginary parts of the self-energy that resembles the Miyake-Narikiyo tiny gap out-side the unitary elastic scattering limit, and below the threshold zero gap value of 1.0 meV.
A contested legacy: Julius Nyerere and the 2020 Tanzanian election
(2020) Luke Melchiorre
A decade of atmospheric composition observations in the undersampled Central Andes
(2022) Marcos Andrade; Diego Aliaga; Luis Blacutt; Ricardo Forno; René Gutierrez; Fernando Velarde; Isabel Moreno; Laura Ticona; Alfred Wiedensohler; Radovan Krejčí
&lt;p&gt;Ten years of almost continuous observations at the highest Global Atmosphere Watch Regional station in the world are presented here. The Chacaltaya observatory (5240 m asl, 16.3&amp;#186;S, 68.1&amp;#186;W) was set up in December 2011. It is currently the only operational station characterizing optical and chemical properties of climate-relevant aerosol and gases in Bolivia and in a radius of about 1500 kilometers from the station. The observations show a clear influence of the well-marked dry and wet meteorological seasons. In addition, the impact on the Andean mountains of long and mid-range transport of biomass burning products from the lowlands is clearly recorded in different parameters measured at the station. Furthermore, the nearby presence of the largest metropolitan area in the region (~1.8 million inhabitants) is observed almost on a daily basis, and therefore different campaigns were carried out to characterize the area and its influence on our measurements. Specific results from these campaigns are discussed elsewhere. Finally, the topographic complexity represents an important challenge for modeling efforts in order to understand sources and sinks (and associated processes) of the observed parameters, requiring not only high spatial resolution and the correct choice of model options, but a novel way of interpreting these results. The decade of collaboration of an international consortium made it possible to keep the station running successfully. The challenge is now to preserve its functioning for the coming decades in a region with historically few high-quality observations while disrupting environmental and socio-economic changes take place.&lt;/p&gt;
A Dynamic Analysis of Household Decision-Making in Urban Colombia, 1976-1998: Changes in Household Structure, Human Capital and its Returns, and Female Labor Force Participation
(2002) Fabio Sánchez Torres; Jairo Núñez
The objective of this paper is to examine the changes and dynamics of household structure, human capital and the returns to education, labor earnings, women's labor force participation and investment in human capital. The approach used in the analysis is the so-called "cohort technique," which consists of following across time men and women born in the same year or year spell. The main sources of information for this work are the quarterly Household Surveys beginning in 1976. With such information a database of more than 6 million observations (workers, parents, children, etc.) was constructed. The research results show that the number of children of the younger parents has drastically decreased.
A European aerosol phenomenology-6: Scattering properties of atmospheric aerosolparticles from 28 ACTRIS sites
(2017) Marco Pandolfi; Lucas Alados‐Arboledas; Andrés Alástuey; Marcos Andrade; Begoña Artı́ñano; John Backman; Urs Baltensperger; Paolo Bonasoni; Nicolas Bukowiecki; Martine Collaud Coen
Abstract. This paper presents the light scattering properties of atmospheric aerosol particles measured over the past decade at 28 ACTRIS observatories, located mainly in Europe. The data include particle light scattering (σsp) and hemispheric backscattering (σbsp) coefficients, scattering Ångström exponent (SAE), backscatter fraction (BF) and asymmetry parameter (g). A large range of ssp was observed across the network. Low ssp values were on average measured in Nordic and Baltic countries and in Western Europe whereas the highest σsp were measured at regional sites in eastern and central Europe. In these regional areas the SAE was also high indicating the predominance of fine-mode particles. On average, the SAE was lower in the Nordic and Baltic, western and southern countries suggesting a lower fraction of fine-mode particle compared to central and eastern Europe. An increasing gradient of ssp was observed when moving from mountain to regional and to urban sites. Conversely, the mass-independent SAE and g parameters did not show the same gradient. At all sites, both SAE and g varied greatly with aerosol particle loading. The lowest values of g were always observed under low ssp indicating a larger contribution from particles in the smaller accumulation mode. Then, g steeply increased with increasing ssp indicating a progressive shift of the particle size distribution toward the larger end of the accumulation mode. Under periods of high particle mass concentrations, the variation of g was less pronounced whereas the SAE increased or decreased suggesting changes mostly in the coarse aerosol particles mode rather than in the fine mode. The station placement seemed to be the main parameter affecting the intra-annual variability. At mountain sites, higher σsp was measured in summer mainly because of the enhanced boundary layer influence. Conversely, less horizontal and vertical dispersion in winter led to higher σsp at all low altitude sites in central and eastern Europe compared to summer. On average, these sites also showed SAE maxima in summer (and correspondingly g minima). Large intra-annual variability of SAE and g was observed also at Nordic and Baltic countries due to seasonal-dependent transport of different air masses to these remote sites. Statistically significant decreasing trends of σsp were observed at 5 out of 13 stations included in trend analyses. The total reductions of ssp were consistent with those reported for PM2.5 and PM10 mass concentrations over similar periods across Europe.
A Flexible Methanol-to-Methane Thermochemical Energy Storage System (Tces) for Gas Turbine (Gt) Power Production
(RELX Group (Netherlands), 2023) D. Pastor; A. Garcia-Guzman; I. Marqués-Valderrama; C. Ortiz; E. Carvajal; J.A. Becerra; V.M. Soltero; Ricardo Chacartegui
A genomic history of the North Pontic Region from the Neolithic to the Bronze Age
(2024) Alexey G. Nikitin; Iosif Lazaridis; Nick Patterson; Світлана Іванова; Мykhailo Videiko; V. A. Dergachev; Nadezhda Kotova; Malcolm Lillie; Inna Potekhina; Marta Krenz‐Niedbała
The north Black Sea (Pontic) Region was the nexus of the farmers of Old Europe and the foragers and pastoralists of the Eurasian steppe 1,2 , and the source of waves of migrants that expanded deep into Europe 3–5 . We report genome-wide data from 78 prehistoric North Pontic individuals to understand the genetic makeup of the people involved in these migrations and discover the reasons for their success. First, we show that native North Pontic foragers had ancestry not only from Balkan and Eastern hunter-gatherers 6 but also from European farmers and, occasionally, Caucasus hunter-gatherers. More dramatic inflows ensued during the Eneolithic, when migrants from the Caucasus-Lower Volga area 7 moved westward, bypassing the local foragers to mix with Trypillian farmers advancing eastward. People of the Usatove archaeological group in the Northwest Pontic were formed ca. 4500 BCE with an equal measure of ancestry from the two expanding groups. A different Caucasus-Lower Volga group, moving westward in a distinct but temporally overlapping wave, avoided the farmers altogether, and blended with the foragers instead to form the people of the Serednii Stih archaeological complex 7 . A third wave of expansion occurred when Yamna descendants of the Serednii Stih forming ca. 4000 BCE expanded during the Early Bronze Age (3300 BCE). The temporal gap between Serednii Stih and the Yamna expansion is bridged by a genetically Yamna individual from Mykhailivka in Ukraine (3635-3383 BCE), a site of uninterrupted archaeological continuity across the Eneolithic-Bronze Age transition, and the likely epicenter of Yamna formation. Each of these three waves propagated distinctive ancestries while also incorporating outsiders during its advance, a flexible strategy forged in the North Pontic region that may explain its peoples’ outsized success in spreading their genes and culture across Eurasia 3–5,8–10 .
A Global and Inclusive Just Labor Transition: Challenges and Opportunities in Developing and Developed Countries
(RELX Group (Netherlands), 2024) Brigitte Castaneda Rodriguez; Luis Fernández Intriago; Raphael J. Heffron; Minwoo Hyun
A highly contiguous, scaffold-level nuclear genome assembly for the Fever tree ( Cinchona pubescens Vahl) as a novel resource for research in the Rubiaceae
(2022) Nataly Allasi Canales; Oscar A. Pérez‐Escobar; Robyn F. Powell; Mats Töpel; Catherine Kidner; Mark Nesbitt; Carla Maldonado; Christopher J. Barnes; Nina Rønsted; Natalia A. S. Przelomska
Abstract Background The Andean Fever tree ( Cinchona L.; Rubiaceae) is the iconic source of bioactive quinine alkaloids, which have been vital to treating malaria for centuries. C. pubescens Vahl, in particular, has been an essential source of income for several countries within its native range in north-western South America. However, an absence of available genomic resources is essential for placing the Cinchona species within the tree of life and setting the foundation for exploring the evolution and biosynthesis of quinine alkaloids. Findings We address this gap by providing the first highly contiguous and annotated nuclear and organelle genome assemblies for C. pubescens . Using a combination of ∼120 Gb of long sequencing reads derived from the Oxford Nanopore PromethION platform and 142 Gb of short-read Illumina data. Our nuclear genome assembly comprises 603 scaffolds comprising a total length of 904 Mb, and the completeness represents ∼85% of the genome size (1.1 Gb/1C). This draft genome sequence was complemented by annotating 72,305 CDSs using a combination of de novo and reference-based transcriptome assemblies. Completeness analysis revealed that our assembly is moderately complete, displaying 83% of the BUSCO gene set and a small fraction of genes (4.6%) classified as fragmented. Additionally, we report C. pubescens plastome with a length of ∼157 Kb and a GC content of 37.74%. We demonstrate the utility of these novel genomic resources by placing C. pubescens in the Gentianales order using additional plastid and nuclear datasets. Conclusions Our study provides the first genomic resource for C. pubescens , thus opening new research avenues, including the provision of crucial genetic resources for analysis of alkaloid biosynthesis in the Fever tree.
A Hybrid Conv1D-LSTM Model with Temporal-Difference Reinforcement Learning for Error-Corrected Gas Forecasting in Critical Mining Environments
(2025) Sebastián Vivas; Pablo Andrés Gómez Monsalve; Alejandra Tabares
<title>Abstract</title> Gas accumulation in underground mining remains a critical safety concern, with hazardous levels of methane (CH4), carbon dioxide (CO2), and oxygen (O2) deficiency posing constant risk of accidents. Traditional forecasting approaches such as ARIMA, artificial neural networks (ANNs), and digital twins (DTs)—struggle to adapt in real time due to their reliance on static historical data and stationarity assumptions, leading to delayed or inaccurate anomaly detection under non-stationary conditions. In response to these limitations, we propose a hybrid forecasting architecture that integrates one-dimensional convolutional neural networks (Conv1D) and long short-term memory (LSTM) units with a reinforcement learning (RL) module based on semi-gradient temporal-difference learning. The proposed framework combines hierarchical feature extraction and temporal memory from the ANN with a correction mechanism via residual-driven reward optimization in RL. Evaluated on minute-resolution gas sensor data from a high-risk underground coke mine in Norte de Santander, Colombia, the hybrid model achieved substantial improvements in predictive accuracy. our model reduces CH4 RMSE from 4.56% with ARIMA to 0.91% with Conv1D–LSTM and further to 0.89% with RL, lowers MAE from 0.89% to 0.52% then to 0.47%, and cuts SMAPE from 82.9% to 74.2% and finally to 31.5%. For CO2, RMSE decreases from 0.21% to 0.17% and to 0.03%, MAE from 0.15% to 0.12% and to 0.02%, and SMAPE from 70.8% to 56.6% and to 8.4%. For O2, RMSE falls from 0.59% to 0.29% and to 0.09%, MAE from 0.26% to 0.21% and to 0.06%, and SMAPE from 1.34% to 0.99% and to 0.23%. These comprehensive gains demonstrate RL’s effectiveness as an error‑correction layer, enhancing both accuracy and responsiveness of deep sequence models in volatile, safety‑critical mining environments. These findings are a solid foundation for future studies in another high-risk environments.
A Hybrid Optimization and Data-Driven Approach to Understand the Role of the Risk-Aversion Profile Parameter in Portfolio Optimization Problems with Shorting Constraints
(RELX Group (Netherlands), 2023) Francisco Fernández‐Navarro; Mariano Carbonero-Ruz; Antonio M. Durán-Rosal
A latitudinal gradient of reference genomes
(2024) Ethan Linck; Carlos Daniel Cadena
Abstract Global inequality rooted in legacies of colonialism and uneven development can lead to systematic biases in scientific knowledge. In ecology and evolutionary biology, findings, funding and research effort are disproportionately concentrated at high latitudes while biological diversity is concentrated at low latitudes. This discrepancy may have a particular influence in fields like phylogeography, molecular ecology and conservation genetics, where the rise of genomics has increased the cost and technical expertise required to apply state-of-the-art methods. Here we ask whether a fundamental biogeographic pattern—the latitudinal gradient of species richness in tetrapods—is reflected in available reference genomes, an important data resource for various applications of molecular tools for biodiversity research and conservation. We also ask whether sequencing approaches differ between the Global South and Global North, reviewing the last five years of conservation genetics research in four leading journals. We find that extant reference genomes are scarce relative to species richness at low latitudes, and that reduced-representation and whole-genome sequencing are disproportionately applied to taxa in the Global North. We conclude with recommendations to close this gap and improve international collaborations in biodiversity genomics.
A Leadership Role Analysis regarding the Performance, Motivation and Stress Levels of Software Professionals in Remote Work
(RELX Group (Netherlands), 2025) Camilo Daza-Ramírez; Kelly Garcés; Aurora Vizcaíno; Elvira Rolón; Juan Pablo Soto; Félix García; Gabriela N. Aranda
A Light of Hope? Inequalities in Mental Health and The Peace Agreement in Colombia: A Decomposition Analysis
(2020) Sebastián León-Giraldo; Germán Casas; Juan Sebastián Cuervo-Sánchez; Catalina González-Uribe; Antonio Olmos; Noémi Kreif; Marc Suhrcke; Oscar Bernal; Rodrigo Moreno‐Serra
<title>Abstract</title> <bold>Background: </bold>The present<bold> </bold>study seeks to evaluate the evolution of mental health inequalities in the department of Meta after the signing of Colombia's Peace Agreement in 2016 with the FARC guerrilla group. Using a validated survey instrument composed of 20 questions (‘SRQ-20’), we measure changes in mental health inequalities from 2014, before the signing of the agreement, to 2018, after the signing of the agreement. We then decompose the changes in inequalities to establish which socioeconomic factors explain differences over time.<bold>Methods: </bold>Our study uses information from the <italic>Conflicto, Salud y Paz </italic>(CONPAS) survey<bold> </bold>conducted in the department of Meta, Colombia, in 1,309 households in 2018, with retrospective information for 2014. To measure inequalities, we calculate the concentration indices for both years. Through the Oaxaca change decomposition method, we disaggregate changes in mental health inequalities into its underlying factors. This method allows us to explain the relationship between changes in mental health inequalities and reduced inequality in several sociodemographic factors. It also identifies the extent to which these factors help explain the changes in mental health inequalities. <bold>Results: </bold>Mental health inequalities in Meta were reduced almost by half from 2014 to 2018. In 2018, the population at the lower and middle socioeconomic levels had fewer chances of experiencing mental health disorders in comparison to 2014. The reduction in mental health differences is mostly attributed to reductions in the influence of certain sociodemographic variables, such as residence in rural zones and conflict-affected territories, working in the informal sector, or experiencing internal displacement. However, even though mental health inequalities have diminished, overall mental health outcomes have worsened in these years. <bold>Conclusions: </bold>The reduction in the contribution of conflict-related variables for explaining mental health inequalities could mean that the negative consequences of conflict on mental health have started to diminish in the short run after the peace agreement. Nevertheless, conflict and the presence of other socioeconomic inequalities still contribute to persistent adverse mental health outcomes in the overall population. Thus, public policy should be oriented towards improving mental health care services in these territories, given the post-accord context.

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