Introduction: the research evaluates the effect of two types of organic fertilizers on the morpho-agronomic characteristics of two varieties of Jamaica (Hibiscus sabdariffa L.) under field conditions in the Tena canton, Napo province, Ecuador. Objectives: to evaluate the effect of the application of poultry manure and worm humus on the growth, development, and yield of two varieties from Jamaica, and to identify the morpho-agronomic differences between them. Methodology: variables such as germination percentage, plant height, leaf width and length, days at flowering, fruit weight per plant and yield were analyzed. Data were evaluated using analysis of variance (ANOVA) and Tukey's mean comparison tests at 5% significance. Results: the results showed significant differences in the percentage of germination between varieties, with Estrella Costeña (88 %) standing out compared to Patriota (76.3 %). In the morpho-agronomic variables related to vegetative growth, the fertilizer factor was highly significant, evidencing that poultry manure and worm humus promoted greater leaf development and a higher plant height compared to the control treatment without fertilization. During the reproductive phase, organic fertilizers accelerated flowering and increased the weight of fruit per plant, which was reflected in an increase in yield. Conclusions: the results indicate that, although variety influences initial vigor and germination capacity, organic fertilization is the most crucial factor in determining the final yield of the Jamaican crop. General area of study: Agronomy. Specific area of study: Plant nutrition. Item type: Original.

Introduction. Gears are essential and expensive elements in industrial processes that suffer severe operational wear. To mitigate catastrophic failures and unplanned downtime, it is crucial to implement effective diagnostic strategies that continuously monitor the mechanical condition of the system. Objective. To analytically evaluate and compare the behavior and sensitivity of vibrational and ultrasonic signals in the presence of common fault modes in spur gears. Methodology. In this applied research with an experimental design, a practical approach was used through the recording and processing of dynamic signals from a parameterizable test bed. Global vibration and sound pressure measurements were collected using specialized sensors under controlled conditions of induced defects. Results. Statistical analysis showed that the root-mean-square vibration velocity parameter (VRMS) has a direct and superior correlation for detecting mechanical angular misalignments. Conversely, the overall ultrasonic sound pressure level (NPT) demonstrated exclusivity and high sensitivity against the progression of severe wear on the tooth flanks. Meanwhile, ultrasound waveform analysis proved to be more favorable for detecting broken gear teeth. Conclusion. It was determined that the complementary combination of vibrational analysis and passive ultrasound optimizes timely diagnosis in spur gear transmissions. The joint use of both techniques reduces predictive uncertainty by specializing each tool according to the geometric nature of the fault. General Area of Study: Industrial Maintenance. Specific area of study: Condition-Based Maintenance. Type of study: Original article.

Introduction: the incorporation of uncertainty in heat conduction models allows us to represent random perturbations present in various physical processes. Objectives: the objective of this research is to compare the deterministic and stochastic formulations of the one-dimensional heat equation under additive Gaussian white noise and to analyze the influence of thermal diffusivity on the propagation of uncertainty. Methodology: a validated and reproducible computational simulation for stochastic partial differential equations was implemented in the MATLAB software, considering a deterministic model using the Crank-Nicolson scheme and a stochastic formulation using the Euler-Maruyama method. Uncertainty was modeled with additive Gaussian white noise and evaluated using 200 Monte Carlo simulations in aluminum, stainless steel, and wood. RMSE, maximum variance, and average thermal energy were used as metrics. Results: the means of the Monte Carlo assembly showed a high agreement with the deterministic solution. The increase in noise intensity increased the statistical dispersion, while the average thermal energy remained practically constant. Conclusions: in conclusion, thermal diffusivity acts as a natural uncertainty dampening mechanism, mainly affecting the variability of the solution without significantly modifying the average dynamics of the diffusive process. General area of study: Applied Mathematics. Specific area of study: Computational simulation. Type of study: Original articles.

Introduction. Salinity may leave the onset of germination unchanged while impairing the formation of functional seedlings, early growth, and biomass accumulation in soybeans. Objective. To evaluate the response of soybean seeds to 0, 50, and 100 mM NaCl using early germination, seedling normality, growth, and biomass indicators. Methodology. A completely randomized design was used with three treatments and six experimental units per treatment, each containing 50 seeds from a commercial lot whose varietal identity was not declared. The test was maintained for eight days at 25 ± 2 °C under a 12 h photoperiod. Germination on day 5, normal seedlings on day 8, shoot and root lengths, water loss, and dry mass were measured. Data were analyzed by one-way ANOVA and Tukey’s test at 5%. Results. Day-5 germination remained between 88.83% and 94.00%, with no statistical differences. In contrast, normal seedlings decreased from 83.33% in the control to 57.83% and 45.83% at 50 and 100 mM. At 100 mM, shoot and root lengths reached 1.85 and 3.20 cm, water loss increased to 79.34%, and root and shoot dry mass decreased to 0.06 and 0.87 g. Conclusion. The evaluated seed lot retained a high capacity to initiate germination, whereas early seedling establishment was sensitive to NaCl, especially at 100 mM. Seedling normality, growth, and biomass discriminated against stress more effectively than the first germination count. General area of study: Agricultural sciences. Specific area of study: Plant physiology and seed technology. Type of study: Original article.