University of San Simón

En el departamento de Pando, Bolivia, se generan grandes cantidades de residuos de pepa de asaí sin un aprovechamiento adecuado. Este estudio evaluó el desempeño térmico y ambiental de una cocina mejorada de biomasa tipo Batch, conforme a la normativa NB/ISO 19867-1, utilizando pellets de aserrín de pino y mezclas con residuos de asaí como combustibles alternativos. Se realizaron pruebas experimentales con diferentes combinaciones de combustible (100% pellets de pino, 40% asaí - 60% pellets, y 30% asaí - 70% pellets) para analizar la eficiencia térmica, consumo energético, emisiones de CO, CO₂ y SO₂. Se emplearon pruebas de hervor de agua y un analizador de gases para la evaluación. Los resultados indicaron que el uso de pellets puros alcanzó una eficiencia térmica del 35%, mientras que las mezclas con asaí registraron 34.20% y 34.61%, la concentración de CO varió entre 407 ppm (pellets puros), 408 ppm (mezcla 30% asaí, velocidad alta) y 310 ppm (mezcla 30% asaí, velocidad media), con una concentración máxima de CO₂ del 2.47% v/v y 4 ppm de SO₂ aproximadamente. El estudio concluye que la combinación de residuos de asaí con pellets de pino en cocinas mejoradas representa una alternativa viable y sostenible para reducir el impacto ambiental y aprovechar desechos agroindustriales en Bolivia.

Introducción: La amebiasis, causada por Entamoeba histolytica, continúa siendo un problema relevante de salud pública en países de ingresos medios como Bolivia, donde su transmisión está asociada a deficiencias en saneamiento básico y acceso limitado a agua segura. A pesar de su notificación obligatoria, existe escasa información actualizada sobre su distribución clínica y comportamiento epidemiológico a nivel departamental, lo que limita el diseño de intervenciones efectivas. Metodología: Es un estudio descriptivo y retrospectivo basado en registros oficiales del subsector público (SDIS/SNIS) del departamento de Cochabamba correspondientes al año 2024. Se incluyeron todos los casos codificados con CIE-10 A06.0–A06.9. Se analizaron variables como edad, sexo y tipo clínico mediante frecuencias absolutas y relativas. Para determinar la asociación entre grupo etario y forma clínica, se aplicó la prueba de Chi-cuadrado (χ²), estableciendo un nivel de significancia del 5 %. El análisis se efectuó en Jamovi 2.4. Resultados: Se notificaron 22.074 casos de amebiasis. La disentería amebiana aguda (A06.0) fue la forma predominante (96,3 %). La mayor carga se presentó en la niñez (0–9 años), que concentró el 46,7 % de los casos. Las formas invasivas fueron poco frecuentes: absceso hepático (n = 27), cerebral (n = 6) y pulmonar (n = 2). Se evidenció asociación significativa entre grupo etario y forma clínica (p < 0,001). Discusión: La elevada carga en población infantil refleja condiciones sanitarias deficientes y exposición temprana. Las formas invasivas, aunque raras, indican diagnósticos tardíos. Se recomienda fortalecer la vigilancia epidemiológica, mejorar el diagnóstico diferencial y promover intervenciones de saneamiento y educación sanitaria para reducir la transmisión y evitar complicaciones.

Abstract This study reports the first confirmed records of Culex (Culex) acharistus, Root, 1927 in Bolivia, based on both morphological examination and biomolecular identification using the cytochrome c oxidase subunit I (COI) marker. Specimens were collected in four localities representing diverse environmental settings: La Paz (urban environment, ≍3600 m), the nearby high-altitude city of El Alto (≍4000 m), Cochabamba (semi-rural and urban habitats, ≍2600 m), and Licoma a large village in the Yungas region (subtropical environment, ≍1900 m). The larval habitats where the species was found closely match those reported in neighboring countries where Cx. acharistus also occurs, ranging from typical small peridomestic sites to ponds, ditches, and river seepages in semi-rural areas. All identification methods yielded unambiguous results, confirming the species’ presence in Bolivia and extending its known distribution in South America. This finding highlights the importance of integrating morphological and molecular approaches to achieve accurate and reliable mosquito species identification.

ABSTRACTWeight‐Length Relationships (WLRs) provide a basis for comparing life history strategies and morphological differentiation among fish species, potentially linking slope variations to evolutionary divergences in size and weight. This study presents the WLRs of nine Serrasalmus piranha species from the Amazon and La Plata basins in Bolivia, assessing whether WLRs slopes are influenced by phylogenetic relationships using a phylogenetic mixed model analysis on the mitochondrial DNA COI (barcoding) locus. All species demonstrated an exponential (power‐type) growth pattern, with most showing positive allometric growth. The species showing the greatest differentiation in both WLRs and genetic variation was S. elongatus. We detected a strong phylogenetic signal in WLR slopes, though clustering techniques for WLRs slopes and molecular data revealed only partial concordance. We discuss how these concordances and discrepancies between WLRs and genetic data may reflect ancient and intermediate speciation events, shaped by habitat conditions and stochastic evolutionary processes. Such processes appear to influence swimming mechanisms and ecological niche navigation in these closely related Serrasalmus species.

Extreme environments comprise a significant portion of Earth’s terrestrial surface, posing challenges, such as extreme temperatures, pressure, pH extremes, oxygen and nutrient scarcity, and high salinity. Hypersaline ecosystems, such as those in the Andean Cold Deserts, exemplify extreme environments where microbial life has evolved specialized survival mechanisms. The Central Andean Mountains host extensive salt flats exposed to extreme temperature fluctuations, intense ultraviolet radiation, and high soil salinity. While most studies focus on surface layers, the impact of soil depth on functional diversity remains poorly understood. This study utilized shotgun metagenomics and functional annotation to explore enzymatic diversity across a 8-meter depth gradient in the Uyuni Salt Flat aiming to understand microbial adaptations to depth and abiotic stress. Our findings revealed a complex, stratified microbial ecosystem. Surface layers showed high abundance of amylases, enzymes that degrade accessible carbohydrates, likely derived from photosynthetic communities or surface-imported organic matter. These patterns suggest a dominance of strategies for rapid carbon decomposition. Intermediate depths exhibited elevated lipase and peroxidase activity, reflecting the presence of complex lipids and oxidative stress management, essential for survival in oxygen-limited, high-salinity zones. Lipase support lipid utilization as a carbon source, while peroxidase activity points to redox adaptations for microbial resilience under fluctuating oxidative conditions. Deeper sediment layers showed a shift toward protease and peptidase activity, indicating organic nitrogen recycling in nutrient-deprived environments and suggesting an efficient protein degradation system among halophilic archaea. Peroxidases remained abundant even at these depths, supporting sustained redox regulation and biogeochemical cycling thus enabling microbes to manage redox imbalances in high-salinity, low-oxygen settings. The enzymatic diversity across the depth gradient demonstrates functional stratification and remarkable microbial adaptability to hypersaline conditions. This functional resilience underpins nutrient cycling and organic matter decomposition deep in the salt flats. Notably, the identified halophilic enzymes, stable and active under high-salinity conditions, hold significant potential for biotechnological applications. This study contributes to our understanding of microbial life’s complexity in hypersaline environments, enhancing our ability to harness extremophilic enzymes for biotechnological applications while underscoring the ecological value of these unique habitats.

The Bolivian Altiplano presents extreme environmental conditions, including high altitude, intense UV radiation, low precipitation, freezing temperatures, and saline to alkaline waters. Despite these harsh settings, cyanobacteria thrive in microbial mats, although their diversity remains poorly characterized. This study aimed to explore the morphological and molecular diversity of cyanobacterial mats and their associated microbiomes in saline and freshwater ecosystems of the Bolivian Altiplano. Morphological analyses revealed seven distinct cyanobacterial morphotypes affiliated with Nostocaceae, Coleofasciculaceae, Rivulariaceae, and Microcoleaceae. Amplicon-based analysis of the 16S rRNA gene identified 4.113 ASV for the bacterial community. Of these, 310 were identified as Cyanobacteria, with 134 classified as Cyanophyceae assigned to 32 genera. Phylogenetic reconstruction and sequence identity comparisons resolved 42 cyanobacterial genera across nine orders. Moreover, 30 ASVs grouped into 16 clades unrelated to any known genus, suggesting the presence of potentially novel cyanobacterial lineages. The microbiome associated with these mats was dominated by Alphaproteobacteria, Bacteroidia, Gammaproteobacteria, Clostridia, Cyanophyceae, and Campylobacteria. Functional predictions based on 16S rRNA gene profiles indicated a predominance of phototrophic and chemoheterotrophic metabolisms, along with sulfur respiration, nitrogen fixation, nitrate and nitrite reduction, and fermentation pathways. Notably, nitrogen-fixing cyanobacteria and bacterial groups with bioremediation potential were prevalent, highlighting the ecological importance and possible biotechnological applications of these microbial consortia. This is the first comprehensive metabarcoding analysis of cyanobacterial mats from Bolivia, including their associated microbiomes. Many new bacterial and cyanobacterial taxa remain to be described in these ecosystems. Based on the functional genomic analysis, this work also highlights the great unexplored biotechnological potential of Bolivia’s extreme environments and the functional roles of microbial mats in biogeochemical cycling under polyextreme conditions.

This paper delves into entanglement-related features of one-dimensional and three-dimensional systems comprising two particles interacting through an attractive potential, such as the delta, harmonic, and Coulomb ones. As a quantitative indicator of the amount of entanglement between the particles, we employ the linear entropy of the system’s one-particle marginal density matrices. Except in some particular instances involving the harmonic potential, this quantity is not analytically tractable and requires numerical evaluation. Our aim is to elucidate some aspects of entanglement in hydrogenic systems. Hydrogenic systems, consisting of two particles interacting through the Coulomb potential, are of clear importance in physics and chemistry, but their entanglement properties have started to be explored only recently. To better understand entanglement in those systems, we first analyze one-dimensional systems interacting via Dirac delta and harmonic potentials. Insights gained from these one-dimensional cases provide valuable guidelines for studying entanglement in hydrogenic systems. We numerically investigate, for the interaction potentials already mentioned, and for different types of confinement for the center of mass, how the system’s entanglement varies with the parameters that determine the size and geometry of the system’s quantum state. We find that entanglement depends on a dimensionless quantity given by the quotient of two parameters characterizing the length scales associated with the interaction potential and the center of mass confinement. Entanglement approaches its maximum when the above-mentioned dimensionless quotient tends to its extreme values and adopts its minimum at an intermediate value of the dimensionless quotient. We find that the same general qualitative features of entanglement behavior are observed for different attractive interactions.

Available open access digitally under CC-BY-NC-ND licence. Transnational care practices differ and are not available to everyone in equal measure. Drawing on interviews with migrants’ parents in Bolivia, this book considers the conditions that older people navigate in one of the poorest countries in Latin America and analyses the diverse transnational care practices that migrants and their parents engage in. The findings highlight how socio-economic differences, migration regimes, provision of health and social services mediate transnational care practices. The authors argue that socio-economic differences matter in the ways in which transnational care is practised. The book reveals how some parents can capitalise and further secure their position through their children’s migrations, while others experience extreme levels of vulnerability.