Sistema Regional de Información
en línea para Revistas Científicas de América Latina,
el Caribe, España y Portugal

Introduction: Knowledge of different functions associated with a probability distribution, as well as their properties, can be translated into functions that provide information about different characteristics of the growth process under study. Objectives: To analyze the relationship between individual growth models and the cumulative distribution functions of continuous random variables. Methods: We compare the flexibility and goodness of fit of the Weibull-type model against the von Bertalanffy weight growth model. We fit these two growth models into two very different sets of age-weight data taken from the literature; the first comprises 22 pairs of Pacific halibut mean weight at age, and the second 900 pairs of striped bass weight-age-data. Results: The Weibull-type growth model had greater flexibility and neglected less information available in the data sets than the von Bertalanffy model. Conclusions: The Weibull model, derived from cumulative probability distribution, is a good choice to fit weight-at-age data as it is more flexible than the commonly used von Bertalanffy model.

Introduction: Helicobacter pylori exhibit variations in antibiotic resistance in America and Colombia. Despite the use of various treatment regimens containing amoxicillin in the department of Antioquia, Colombia, as well as in several countries across the continent, the pattern of genotypic and phenotypic susceptibility to this antibiotic remains unknown. Objective: To determine the frequency of H. pylori infection by detecting the ureA gene and amoxicillin susceptibility through beta-lactamases in H. pylori isolates from patients with gastroduodenal diseases in Antioquia-Colombia. Methods: Cross-sectional analytical study with 179 patients attending endoscopy units of seven healthcare institutions. Sociodemographic and risk factor data were collected. Moreover, biopsies from the antrum and body were taken for microbiological isolation and molecular detection of H. pylori. The sociodemographic data were assessed through frequency analysis and bivariate statistics. DNA obtained from the biopsies was amplified by PCR for the ureA gene, and beta-lactamase production was evaluated using the nitrocefin test as well as the amplification of the TEM and SHV genes. Results: It was found that 61 % (109 / 179) of patients tested positive for H. pylori; out of 84 isolates obtained by culture, none tested positive for the nitrocefin test. Significant differences were found in socioeconomic status, healthcare system, and geographical location in patients positive for the ureA gene. Two patients tested positive for molecular detection of beta-lactamases from biopsies; however, SHV and TEM genes were not found in any isolate. Conclusions: The frequency of H. pylori for ureA-gene detection is higher than previous studies and similar to other reports in other Colombian regions; consequently, this will become a good diagnostic test in the country. Finally, none of the H. pylori isolates tested positive for beta-lactamases TEM and SHV.

Introduction: Dry and humid forests are among the most threatened on the planet in Colombia, they are in Critical Danger, but the status of the transitions is unknown. Objective: To establish the distribution, level of fragmentation, and floristic affinities of the transitional areas between the Tropical Dry Forest (TDF) and Tropical Wet Forest (TWF) in the climatic gradient of the Sinú River basin as a contribution to its conservation management. Methods: The Forest/Non-Forest (B/NB) layer of the study area was at a scale of 1 : 25 000 with Sentinel images (2021-2022) from Planet Scope and other sources, we identified the climatic regions, using climatic data from WorldClim 2.0 (1970-2000) and Giovanni 4.38 (2001-2021), we estimated the level of fragmentation, and we identified floristic affinities from liana sampling and a clustering analysis. Results: The basin has 462 972 ha of forests, 5 % are dry-humid transitional forests, 87 % are humid forests, 6 % are dry forests, and 2 % are mangrove forests. There are more than 1 000 ha of transitional forests in high-extreme fragmentation. The TWF has the lowest fragmentation (little-minimal) and the TDF is the most fragmented. The forested transitions of the basin are more floristically related to TDF. Conclusions: This study contributes to closing the gap in knowledge for determining the distribution patterns of transitional dry-humid tropical forests in the Sinú River basin by applying a replicable integrative methodology. These dry-humid transitional forests should be recognized as another important type of cover for the study of ecological processes under climate change scenarios. It is proposed that dry-humid forests should be included in conservation priorities in the planning and management processes of the territory at different geographic scales and management levels.

Introduction: Functional traits analysis allows an understanding of the mechanisms that structure plant communities epiphytes. The distribution of taxonomic and functional epiphyte diversity along vertical gradients is a key tool to track epiphytes’ response to environmental changes, especially in biodiversity hotspots, where a high number of endemic species are threatened. Objective: To relate the taxonomic and functional epiphyte diversity and their vertical distribution with forest structural variables of the Montane and Dry Forest ecosystems in the Colombian Andes. Methods: Epiphyte diversity in each study site was recorded in 35 random phorophytes. Alpha and functional diversity were compared for five vertical strata of the canopy (Z1-Z5) and related to forest structural and floristics variables such as tree richness, tree density, diameter at breast height (DBH), canopy height, crown area, and canopy openness. Results: The Montane Forest presented a greater diversity of epiphytes, mainly orchids, with Stelis angustifolia as the dominant species. In contrast, the Dry Forest presented a greater Bromeliad abundance, and Tillandsia recurvata was dominant. Montane forest epiphytes were represented by three functional groups: tank-bromeliads, shallow tank-bromeliads, and ramicauls-orchids, while in the Dry Forest shallow tank-bromeliads and nebulophyte-bromeliads. Positive correlations were found between epiphyte richness, abundance, and diversity with variables related to phorophyte size (DBH and crown area) in montane forest. There was also a different tendency on the preference for some strata between Orchids (Z2-Z3) and Bromeliads (Z3-Z4). Conclusion: Differences were found in the taxonomic and functional diversity of epiphytes between the two forests, where orchids and bromeliads often coexist in similar environments but are distributed in different habitats, resulting from adaptation to specific environmental conditions, which allows them to coexist in different niches within the ecosystem.

Introduction: The ocelot Leopardus pardalis, though currently listed as Least Concern on the IUCN Red List, has a declining population, and faces threats such as habitat loss and fragmentation and hunting across the entirety of its geographical range, from the Southwestern United States to Northern Argentina. Being a cryptic species and with few studies monitoring ocelots over multiple years, there is a lack of information regarding ocelot ecology. Objective: To further understand the behaviour and population dynamics of ocelots within the study area, Tortuguero National Park (45 755 ha), Costa Rica, by analysing data from a long-term camera trapping study (2011-2022). Methods: Individual ocelots were identified using their unique spot markings. Sex ratio, daily activity patterns, and behaviour were evaluated, whilst ocelot minimum age was estimated for each individual and designated as either resident or transient based on the number of consecutive years observed in the study. Results: A total of 30 individual ocelots were identified (12 females, 18 males). The daily activity pattern (nocturnal) and sex ratio (1 : 0.7) were consistent with that described for the species. The movement of one individual from Tortuguero National Park to Pacuare Nature Reserve, 41 km South, highlights the importance of wildlife corridors for the species. The study also revealed evidence of a female ocelot at least 14 years of age. There are very few published occurrences of an ocelot this old in the wild. Scent marking behaviour was also recorded. Conclusions: This is the longest monitoring effort for ocelots in the country, to our knowledge. Our results highlight the importance of and need for further long-term studies of ocelots to enhance understanding of the species and thus promote the conservation of the species and its habitat.

Introduction: Research into the ontogeny of sporangia and sporogenesis of leptosporangiate ferns is scarce in the scientific literature. Objectives: To describe and analyze the ontogeny of sporangia, sporogenesis, micromorphology, and ultrastructure of mature spores of the fern Anemia hirsuta. Methods: Fertile fronds of A. hirsuta were processed according to standard protocols for sectioning and embedding samples in paraffin and resin. Sections in paraffin were stained with safranin-alcian blue, Toluidine Blue, and PAS/amidoblack. Sections in resin were stained with Toluidine Blue. The samples were prepared for observation under scanning electron microscopy (SEM) to yield detailed descriptions. Mature spores were analyzed by X-ray energy dispersion (XEDS). Ultrathin sections were obtained for transmission electron microscopy (TEM) observation. Results: The entire leptosporangium is formed from a basal and an apical cell derived from a single epidermal cell of the fertile pinna. The mature leptosporangia are globose, with a subapical ring and a short pedicel. During development, the tapetum is initially cellular, and then becomes plasmodial. The sporocytes undergo simultaneous meiotic division to form tetrads of spores in a tetrahedral arrangement. The exospore is formed first, with two layers, a very thin internal layer and a thick outer layer, followed by the endospore, and finally the perispore. The spores are trilete and muriform, with simple or branched siliceous microspines. The perispore associated with the muri and grooves appears to be highly organized with evident ultrastructural differences. Conclusions: The ontogeny of the sporangia and sporogenesis of A. hirsuta is similar to that previously described for leptosporangiate ferns and recorded in some related fossil species. The highly structured and organized perispore is observed. A high silica content in the microspines of the sporodermis is herein reported for the first time in this group.

Introduction: Jaguars (Panthera onca) and pumas (Puma concolor) are the two largest terrestrial predators in lowland Neotropical forests and as such, are important contributors to the ecosystem. Yet, long-term studies on their temporal and spatial patterns of occurrence are not common. Objectives: To update a previous eight year (2005-2012) camera-trap study on jaguars at Tiputini Biodiversity Station, Yasuní Biosphere Reserve, with data from 2014 through 2023; and to add complementary information on pumas. Methods: We used camera traps set along trails or at mineral licks to document the occurrence of jaguars and pumas. Individual jaguars were identified by their distinctive coat patterns. Results: Capture rates from 2014 to 2023 varied from 0 to 2.94 images/100 trap days for jaguars and from 0.46 to 4.88 for pumas. These rates were similar or increased across all years for both species. We identified 28 individual jaguars during the second sample period, including 18 males and seven females. Periods between captures ranged from 1 to 84 months, with eight individuals recorded over at least 36 months. Including images from the first period (2005-2012), when 21 individuals were identified, it is likely that ~50 individual jaguars have occurred in or close to the research station over 19 years. Jaguars were primarily active during daylight hours, while pumas were more active at night. Conclusions: TBS is embedded within a large biosphere reserve but is too small (~670 ha) to cover the home range of either species. Nonetheless, given the number of records and the fact that capture rates have not declined in the past two decades, this region is important for the conservation of these two species and the many prey they depend on.

Introduction: In this article, we derive the behavior of four different mass testing strategies, grounded in guidelines and public health policies issued by the Costa Rican public healthcare system. Objective: To formally develop the changes of each studied mass testing strategy under different contexts related to people’s risk, costs of testing, and accessibility to alternative testing technologies. Methods: We take over a pre-classifier applied to individuals capable of partitioning suspected individuals into low-risk and high-risk groups. We consider the impact of three testing technologies: RT-qPCR, antigen-based testing, and saliva-based testing (RT-LAMP). When available, we introduced a category of essential workers. Results: Numerical simulation results confirm that strategies using only RT-qPCR tests cannot achieve sufficient stock capacity to provide efficient detection regardless of prevalence, sensitivity, or specificity. Strategies that harness the power of pooling and RT-LAMP either maximize stock capacity, detection efficiency, or both. Conclusions: Investing in data quality and classification accuracy can improve the odds of achieving pandemic control and mitigation. Future work will be focused on, based on our findings, constructing representative synthetic data through agent-based modeling and studying the properties of specific pre-classifiers under various scenarios.

Introduction: Corticolous lichens are organisms that respond to habitat modifications, which is why they are considered model organisms to evaluate environmental changes in different ecosystems. Objectives: To determine the species richness and community composition of corticolous macro lichens in montane forests and forest remnants. In addition, the effect of microclimatic factors in three areas with different degrees of light intensity and density of arboreous vegetation on the species distribution of recorded diversity was evaluated. Methods: The study was conducted in the Volcan Baru National Park, Panama. Three areas with different forest densities and host tree species, Comarostaphylis arbutoides and Quercus spp., were chosen, considering a total of 60 trees, 10 of each species in each area. The canopy's opening close to the host trees and its diameter at breast height were recorded. Linear models and multivariate analysis was used to determine changes in species richness and composition of epiphytic macro lichens. Results: The characteristics of the host trees (e.g. host species and area) conditioned the species richness, while the communities were limited by microclimatic changes (e.g. light) in different areas. Conclusion: The macro lichens communities analyzed responded to changes related to the host tree species and the microclimate, so they can be considered indicators of ecological continuity in tropical montane forests.

Introduction: Lac resin, the only natural resin of animal origin, is exclusively produced by the lac insect (Kerria spp.). It is non-toxic and considered biodegradable. However, the bacteria involved in biodegradation have not been explored. Moreover, the fate of the soil bacteria during biodegradation has not been studied so far. Objective: To explore the fate of soil bacteria due to the burial of seedlac in soil to ascertain whether seedlac is environmentally safe, and to explore the possibilities of identifying any bacterial flora involved in lac biodegradation. Methods: The study began in 2016 by burying seedlac samples (semi-refined lac resin product) in the field soil and pot soil under replicated conditions. The seedlac samples were drawn from the soil in 2019, and the soil adhering to the seedlac samples was used in further experiments. The bacterial diversity of these soils was documented by sequencing the V3-V4 region of 16S rRNA through the Illumina NGS platform. Results: No significant variations were obtained in the soil bacterial diversity between samples except for the marginal increase in the count of Actinobacteria, Myxococcales, Gemmatales, Gemmataceae, the WD2101-soil group in seedlac buried pot soil, and Proteobacteria and Acidobacteria in field soil. Most of these bacterial groups are known to degrade complex organic polymers. Conclusions: Since there are no changes in the soil bacterial diversity due to seedlac burial, it may be concluded that seedlac does not affect the soil microflora and is safe for the soil environment.