RESUMEN
Genera and species of Elmidae (riffle beetles) are sensitive to water pollution; however, in tropical freshwater ecosystems, their requirements regarding environmental factors need to be investigated. Species distribution models (SDMs) were established for five elmid genera in the Paute river basin (southern Ecuador) using the Random Forest (RF) algorithm considering environmental variables, i.e., meteorology, land use, hydrology, and topography. Each RF-based model was trained and optimised using cross-validation. Environmental variables that explained most of the Elmidae spatial variability were land use (i.e., riparian vegetation alteration and presence/absence of canopy), precipitation, and topography, mainly elevation and slope. The highest probability of occurrence for elmids genera was predicted in streams located within well-preserved zones. Moreover, specific ecological niches were spatially predicted for each genus. Macrelmis was predicted in the lower and forested areas, with high precipitation levels, towards the Amazon basin. Austrelmis was predicted to be in the upper parts of the basin, i.e., páramo ecosystems, with an excellent level of conservation of their riparian ecosystems. Austrolimnius and Heterelmis were also predicted in the upper parts of the basin but in more widespread elevation ranges, in the Heterelmis case, and even in some areas with a medium level of anthropisation. Neoelmis was predicted to be in the mid-region of the study basin in high altitudinal streams with a high degree of meandering. The main findings of this research are likely to contribute significantly to local conservation and restoration efforts being implemented in the study basin and could be extrapolated to similar eco-hydrological systems.
RESUMEN
Background: concern about the quality of the water for human consumption has become widespread among the population. The taste and some problems associated with drinking water have been the cause of increased demand for bottled water. Due to this, day to day, a large number of companies has manifested their interest in the production of bottled water. Objective: to evaluate a novel automatic classification model that differentiates bottled water from tap water. Methods: the voltammetric technique consisted of three electrode setup. The output current has been considered for data analysis. From the results of grid search, six pairs of values were pre-selected for the parameters of σ and C whose results were similar. High values of accuracy, specificity and sensitivity were achieved in test dataset. The final decision was made after performing an ANOVA test of 100 repetitions of 5-fold cross-validation, 3000 models were evaluated with the parameter combinations described above for the SVM. Results: the oxidation and reduction peaks of the water samples have been observed to be prominent. Absolute values of current (I) increased in the case of public water samples, possibly due to the largest concentration of chloride ions which have higher contributions to the conductivity. 5-fold cross-validation test mean specificity resulted in C parameters values greater than 0 and between 0 and 30; a σ value greater than 10 and between 0 and 15 were found for tap water and bottled water, respectively. The combination (σ = 10, C = 30) presented best results in accuracy 0.988 ± 0.037, specificity 0.973 ± 0.085 and sensitivity 1 ± 0.09. Conclusions: results of this research work have shown that voltammograms for values of current increased for tap water samples, 9.94e-6µA, compared to 7.99e-6µA due to higher chloride ions concentration in the former. The parameters combination (σ = 10, C = 20) was selected as optimal parameters since there were no significant difference between this and the former.
Antecedentes: en la población hay una preocupación generalizada por la calidad del agua de consumo humano. El sabor y algunos problemas asociados con el agua potable han sido la causa del incremento en la demanda del agua embotellada. Debido a esto, un gran número de empresas han manifestado su interés en la producción de agua en botella. Objetivo: evaluar un nuevo modelo de clasificación automática que diferencie el agua embotellada del agua del grifo. Metodología: la técnica de voltametría consistió en la configuración de tres electrodos. Para el análisis de datos se consideró la corriente de salida y de los resultados de la búsqueda de cuadrícula y se seleccionaron seis pares de valores para los parámetros de σ y C, cuyos resultados fueron similares. Se lograron altos valores de precisión, especificidad y sensibilidad en el conjunto de datos de prueba. La decisión final se tomó después de realizar una prueba ANOVA de 100 repeticiones de validación cruzada de 5 veces y se evaluaron 3000 modelos con las combinaciones de parámetros descritas anteriormente para el SVM. Resultados: se observó que los picos de oxidación y reducción de las muestras de agua son prominentes. Los valores absolutos de corriente (I) aumentaron en el caso de muestras de agua pública, posiblemente debido a la mayor concentración de iones de cloruro que tienen una mayor contribución a la conductividad. La especificidad media de la prueba de validación cruzada 5 veces dio como resultado valores de parámetros C mayores que 0 y entre 0 y 30; se encontró un valor σ mayor que 10 y entre 0 y 15 para el agua de red pública y el agua embotellada, respectivamente. La combinación (σ = 10, C = 30) presentó los mejores resultados en precisión 0,988 ± 0,037, especificidad 0,973 ± 0,085 y sensibilidad 1 ± 0,09. Conclusiones: los resultados de este trabajo demostraron que los voltamogramas para valores de corriente, aumentaron para muestras de agua corriente, 9,94e-6 µA, en comparación con 7,99e-6 µA debido a una mayor concentración de iones de cloruro en el primer caso. La combinación de parámetros (σ = 10, C = 20) se seleccionó como parámetros óptimos, ya que no mostró diferencias significativas entre éste y el primer caso.
