Search

Modularity as a system of separate and independent sub-tasks is the appropriate way to improve the performance of artificial neural network (ANN) models in hydrological processes. Using this approach, a block combined neural network (BCNN) structure incorporated with genetic algorithm (GA) and an additional decision block is suggested in this study. The optimum topology of embedded networks in each block was detected using a vector-based method subjected to different internal characteristics. This model was then applied on 879 bedload datasets, considering velocity, discharge, mean grain size, slope, and depth as model inputs over streams in Idaho, USA. The correct classification rate of predicted bedload using BCNN (89.77%) showed superior performance accuracy compared to other ANNs, and to empirical models. Results of computed error metrics and confusion matrixes also demonstrated outstanding progress in BCNN relative to other models. We show that BCNN as a new method with an appropriate accuracy level could effectively be adopted for bedload prediction purposes. [ABSTRACT FROM AUTHOR]

The aim of this research was to evaluate the antibacterial activity of the muscle wall extracts of sea cucumber, Stichopus horrens, against Lactococcus garvieae, Streptococcus iniae, Aeromonas hydrophila, and Yersinia ruckeri bacteria in rainbow trout using the disk-diffusion and well-diffusion methods. In this study, nine sea cucumbers (with the mean weight of 1690 ± 12.18 g) were randomly obtained from two locations in Chabahar Bay, Iran in November 2018. The muscle wall of the body was extracted with each of the ethyl acetate, methanol, and acetone organic solvents. The antibacterial activities of extracts were determined. Only the ethyl acetate extracts of S. horrens in the concentrations at 8 and 12 mg/mL had an inhibitory effect on all the examined bacteria. Y. ruckeri and A.hydrophila bacteria were sensitive to the acetone extracts. The best property was recorded with the S.horrens ethyl acetate extracts, with the MIC value of 0.625 mg/mL against S. iniae and L. garvieae. The MIC values ranging from 0.626 to 1.25 mg/mL were also displayed with the acetone extracts against Y. ruckeri and A. hydrophila, respectively. In conclusion, the ethyl acetate extracts of S. horrens displayed the best spectrum of bactericidal effect obtained from four bacteria strains examined. [ABSTRACT FROM AUTHOR]

The occurrence of local scour around bridge piers or abutments is one of the major reasons for the destruction of bridges. Therefore, this phenomenon should be prevented or at least minimized using some methods, namely using collars in recent years. In the present paper, by proposing a new approach and developing an experimental model of partial collars (collars not fully encircling the abutment), the effect of length and width of collars on reducing scouring and sedimentation pattern around the bridge abutments with vertical walls were investigated under different conditions. Moreover, the obtained results were compared with the results of models with full collars. The results revealed that collar dimensions could have a great impact on its efficiency. In partial collars, if only the upstream face of the abutment is protected and there is no protrusion toward the downstream, there will be no high and acceptable efficiency. However, increasing length and width, its positive efficiency will be enhanced. Although increasing the length of a collar of this type to more than 0.6 times the length of the abutment diminishes the scouring around the bridge abutment, increasing its width not only does reduce the scour depth but also produces a much greater effect on the location of the scouring hole to be farther away from the downstream of the abutment. Furthermore, the efficiency of full collars is also enhanced as their length and width increase. Comparison of the results shows that the efficiency of full collars is less than that of partial collars, despite their greater cross-sectional area. Therefore, partial collars are more cost-effective than full collars due to their lower cross-sectional areas. The average percentage of scour depth reduction for all four flows for different models in the erodible bed and at the base point ranged from 24 to 68% and 24 to 97%, respectively. [ABSTRACT FROM AUTHOR]

We tested the effect of fish oil (FO)-enrichedArtemiaon growth performance and stress resistance in tiger barb (Puntius tetrazona) larvae. Tiger barb larvae (˜2.31 mg) were fed FO-enriched (2.5, 5, 7.5%) or nonenrichedArtemianauplii for 14 days, followed by 14 days on nonenrichedArtemia. FO enrichment significantly increased n-3 HUFA and n-3/n-6 ratio of nauplii. There was no significant difference in survival rate among the treatments. Fish fed enriched nauplii grew better at days 14 and 28, and exhibited greater resistance to osmotic and hypoxia stress. There were no significant differences in growth and stress resistance among FO-enriched groups. [ABSTRACT FROM PUBLISHER]