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The high pressure of water distribution networks (WDNs) increases leakage, bursts, and water consumption. Pressure-reducing valves (PRVs) are widely used in WDNs because of their flexibility and effectiveness in pressure management. This paper studies pressure management by locating and adjusting PRVs in WDNs, considering the proper objective function and the suitable optimization algorithm. The single-objective algorithms and the EPANET hydraulic simulator in MATLAB programming are combined to manage the pressure. Initially, the proposed method improved by selecting the optimal optimization algorithm and objective function. Both fixed outlets and time-modulated modes of PRVs for two ZJ and Bellingham WDNs as case studies were used. Considering the cost, reliability, hydraulic performance, and leakage, the results were then analyzed and compared by changing the number, location, and adjustment of each PRV. The outcomes show the effect of choosing the best algorithms and cost functions on the results. The results also show that this method increases the reliability and controls the nodal pressure to a desired level in WDNs. Practical Applications: Leakages in water distribution networks (WDNs) are problematic for utilities and other governmental agencies. Pressure management in WDNs is inevitable to reduce the rate of bursts and leaks. Using fixed- and time-modulated pressure-reducing valves (PRVs) is essential for smart pressure management in WDNs. This study presented a method for positioning and adjusting PRVs in WDNs. The proposed method was applied to ZJ and Bellingham WDNs by choosing the best optimization algorithm and objective functions. The grey wolf optimizer (GWO) algorithm is proposed as one of the best algorithms for this subject. The presented method tries to provide the best plan for pressure management by examining the cost, leakage, and reliability. The results show that the presented method effectively increases reliability and reduces leakage in WDNs. [ABSTRACT FROM AUTHOR]

This study was carried out to rank and prioritize the aspects that have been shown to have an impact on the improvement of construction project management (CPM) performance based on value engineering. This analysis was carried out with the Iranian construction industry's current situation in mind. The respondents and the Delphi panel were chosen from among Iranian managers and project management professionals with a focus on building projects. These professionals had more than 20 years of experience working on international projects, and in addition to their expertise in project management, they also understood the principles of earned value analysis and value engineering. Thus, the components extracted from the literature review were used as the basis for designing a structured interview based on 39 important effective components previously determined as identified factors. The questionnaires were distributed among the experts, and the returned questionnaires were analysed using the SWARA technique to rank the weight and importance of the factors. Using the SWARA method, the opinions of the expert panel members consisting of 20 engineers and a semi-structured questionnaire was used to gather expertise in project management and managers, with a focus on Iranian CPM. As shown by the results, stakeholder management, time value of money, and worth, allocated the first to the third rank to themselves with respective weights of 0.104, 0.103, and 0.087. The sub-criteria of cost objective, function objective, and value objective were in the 37th to 39th ranks with respective weights of 0.00050, 0.00033, and 0.00021. [ABSTRACT FROM AUTHOR]

The management and operation of water distribution networks (WDNs) by establishing district metered areas (DMAs), especially in existing and old WDNs, has many advantages, including water leakage control, ease of operation, and network management in emergencies. Using DMAs in existing WDNs designed and developed traditionally is a challenging issue because of the need to cover several criteria. In the present study, a method for creating DMAs is suggested to minimize the cost as well as to reduce the average pressure in high-pressure WDNs. The proposed method uses the Girvan–Newman clustering and nondominated sorting genetic algorithm (NSGAII) optimization algorithms. This method was implemented on Modena's and Wolf–Cordera Ranch's WDNs. The proposed method can generate several solutions based on performance indicators, including cost, hydraulics, and quality. The results show that by applying the proposed method in the Modena and Wolf–Cordera Ranch WDNs, the average pressure of the networks was reduced by 17% and 31%, respectively, in comparison with the primary WDNs in the base demand and peak demand conditions. This method can be used by water utilities for partitioning WDNs, especially when the pressure is high. [ABSTRACT FROM AUTHOR]

This paper aims to obtain a relation for estimating the median size of bed sediment, d 50 , at the bends of meandering rivers based on real data. To achieve such a purpose, field data, including topographic, sediment sampling, and flow measurements, were collected from various rivers in Iran at different times of the year. Then, the Buckingham Π-theorem was applied to identify the effective dimensionless numbers such as the Shields function, Reynolds particle number, Froude number, submerged specific gravity of sediment, and aspect and curvature ratios. A correlation analysis was conducted between such factors to eliminate those dependent on others. In the following, three regression techniques, containing the power function approach, the general additive model (GAM), and the multivariate adaptive regression spline (MARS), were chosen to achieve the best relation. The obtained results indicated that the developed MARS model produced a better result than the others and was much more satisfactory, with a coefficient of determination (R2) of 0.96 and 0.95 and root-mean-square error (RMSE) of 140.64 and 140.47 for the training and testing phases, respectively. Furthermore, the MARS outputs were validated with an analytical method, which showed that MARS fitted with the field data much better. Consequently, the distinguished merit of this study is the development of a relation for determining d 50 that shows which geometric and hydraulic parameters have the most effect on sediment size in the river bend. [ABSTRACT FROM AUTHOR]

Near-field earthquakes have been shown to have different effects on structures than far-field events. This study examines the dynamic response of a rectangular concrete liquid storage tank with tapered walls to near-field ground motions, with particular emphasis on the effect of higher sloshing modes. The tank's numerical modeling, calibrated using experimental results, was performed considering the tank's wall flexibility. Seven selected near-field records were applied in each case, and the effects of the first five sloshing modes on the tank response at three different locations, including the corner, middle of the long wall, and middle of the short wall, were investigated. The effect of the earthquake incident angle on the tank's response was also studied by applying major and minor horizontal earthquake components once along the longer and shorter tank walls, respectively, and vice versa. Results show that the tank corner may have a sloshing height up to 50% greater than the middle of the walls and that the maximum sloshing response is substantially influenced by the spectral acceleration value at the first sloshing period. Higher sloshing modes are found to affect the sloshing response, with a maximum R2 score of 0.95, depending on the excitation's incidence angle. [ABSTRACT FROM AUTHOR]

Reservoirs are crucial for water storage, flood control, and electricity generation. At the same time, evaporation in dam reservoirs causes water losses. This study evaluates the effect of weather conditions on the prediction of evaporation from the dam reservoir, and there are several developed models to predict evaporation under different scenarios. Using the deep neural network model long short term memory (LSTM) with a series of modern meta-heuristic algorithms, the present research aims to achieve an acceptable accuracy on weather parameters. The present study investigates the ability of the LSTM deep neural network and meta-heuristic algorithms of Artificial Bee Colony (ABC), Horse Herd Optimization (HOA), and Marine Predators (MPA) to develop an evaporation rate forecasting model for a tropical area in the Dez Dam reservoir, Khuzestan province, Iran. To investigate the effect of different input variable patterns on the prediction accuracy of the case model, twenty-eight scenarios were investigated for the input architecture along with the LSTM model and its combination with meta-heuristic algorithms. The models include ABC-LSTM, LSTM-HOA, and LSTM-MPA, respectively. The results showed that the combined LSTM-MPA model with RMSE, MAE, KGE, and WI evaluation criteria equal to 81.926 mm/month, 53.684 mm/month, 0.850, and 0.816, respectively, performs better than other meta-heuristic models. The examined deep meta-heuristic models are suggested for predicting evaporation from the Dez dam reservoir with limited information because the results show that they have more appropriate prediction capability than the LSTM Model. [ABSTRACT FROM AUTHOR]

This study proposes a numerical model for depth-averaged Reynolds equations (shallow-water equations) to investigate a dam-break problem, based upon a two-dimensional (2D) second-order upwind cell-centre finite volume method. The transportation terms were modelled using a modified approximate HLLC Riemann solver with the first-order accuracy. The proposed 2D model was assessed and validated through experimental data and analytical solutions for several dam-break cases on a wet and dry bed. The results showed that the error values of the model are lower than those of existing numerical methods at different points. Our findings also revealed that the dimensionless error parameters decrease as the wave propagates downstream. In general, the new model can model the dam-break problem and captures the shock wave superbly. [ABSTRACT FROM AUTHOR]

Copyright of Journal of Utilization & Cultivation of Aquatics is the property of Gorgan University of Agricultural Sciences & Natural Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

Copyright of Journal of Utilization & Cultivation of Aquatics is the property of Gorgan University of Agricultural Sciences & Natural Resources and its content may not be copied or emailed to multiple sites or posted to a listserv without the copyright holder's express written permission. However, users may print, download, or email articles for individual use. This abstract may be abridged. No warranty is given about the accuracy of the copy. Users should refer to the original published version of the material for the full abstract. (Copyright applies to all Abstracts.)

This study analyses the impact of climate change on the inflows, sediment loads, and nutrient inputs to the Sabalan dam reservoir, a warm monomictic lake located northwest of Iran. For this purpose, the Soil and Water Assessment Tool (SWAT) was calibrated (2005–2018) and validated (2001–2004). Future climate-based data under the AR5 emission scenarios were obtained from the HadGEM2–ES general circulation model and then downscaled using the LARSWG 6.0. The tuned SWAT model was used to investigate the climate change impact on the hydrological processes and pollution loads to the Sabalan dam reservoir. Our findings based on the Nash–Sutcliffe efficiency coefficient and the coefficient of determination indicated an acceptable performance of the SWAT model in the simulation of inflows, sediment loads, and nutrient inputs to the reservoir. Inflow and sediment load to the reservoir will increase during the period of 2030–2070 compared to the base period (1998–2018). The annual total nitrogen (phosphorus) load to the reservoir will increase by 8.5% (9.4%), 7.3% (8.2%), and 5% (3.4%) under the emission scenarios of RCP2.6, RCP4.5, and RCP8.5, respectively. An increase in sediment loads and nutrient inputs to the Sabalan dam reservoir will significantly exacerbate the reservoir eutrophic condition, leading to water quality deterioration with acute consequences for the positive functions of the dam. [ABSTRACT FROM AUTHOR]

Proper planning and management of construction projects have long been regarded as a necessity. The ability to make sound decisions and solve problems using appropriate performance reports related to the project implementation process are the two most key factors in controlling the performance of construction project management. Even though these factors considerably contribute to controlling precise project performance, previous research has failed to investigate them to their fullest potential. Therefore, this research seeks to fill the existing gap by determining the influential factors on construction project management performance through earned value-based value engineering strategy. In this line, a comprehensive literature analysis was undertaken to extract the influential factors on construction project management performance. Then, three rounds of a Delphi survey were conducted to consolidate the influential factors. There were a total of 39 factors that were grouped into four categories. The identified influential factors were then evaluated through the analysis of quantitative data. The findings showed that the dimension of "Engineering economics" was ranked first in terms of importance, followed by "Project management performance", "Value engineering approach", and "Earned value management" at the second to fourth ranks, respectively. The overall ranking of the factors placed "Project Stakeholder Management" in the first position and "Project Management Software" in the bottom place. It is anticipated that the key findings and effective recommendations of this study will considerably contribute to the improvement of decisions on project planning and improve the performance of construction project management while enhancing different stakeholders' understanding of the most influential factors on the performance of construction project management. [ABSTRACT FROM AUTHOR]

In recent decades, the earth's surface data have been collected more efficiently using remote sensing, which needs drought indexes update. In this study, soil moisture (SM) data were collected from the surface layer of a high humidity climate in northern Iran using Soil Moisture Active Passive (SMAP) and field measurement. After analyzing the data, we found that the average RMSE between the field and SMAP measurement was 0.054 m 3 m 3 . Considering the same agricultural land use and the strong correlation of 0.92 between them, the validated SMAP data were used to propose an agricultural drought index. After data validation, the extreme learning machine (ELM) model was put to the test using sigmoid, triangular, sine, and hard-limit activation functions. Of all the activation functions tested, the model with the sigmoid activation function yielded the lowest amount of error and was therefore chosen. Five years of continuous daily SM as a target, five-year daily normalized difference vegetation index, land surface temperature, and precipitation were inputs to predict one-year daily SM time series in the humid climate. From 2021 to 2022, daily surface SM was predicted with the average RMSE = 0.03 m 3 m 3 compared to the SMAP data. Finally, a new regional agricultural drought index based on 4 years of SMAP and 1-year prediction of SMAP from 2022 to 2023 was proposed. Further investigation is needed to conclude that the application of the presented index is reliable in other climates. [ABSTRACT FROM AUTHOR]

Climate change and its side effects on weather variables and water resources is one of the recent international concerns. This research aims to project future changes in weather variables due to climate change for different emission scenarios of RCP2.6, RCP4.5 and RCP8.5 to assess and compare climate change impact on river flow variation based on hybrid application of deep learning and LARS-WG6 in different climates of Iran (CSA: cold semi-arid; HT: humid temperate; CA: cold arid). For this purpose, best combination of daily rainfall and discharges data with different lags were selected as inputs in rainfall-runoff modeling using Convolutional Neural Networks (CNN) model. Predicted meteorological data by the LARS-WG6 in the future (2021-2040) were then used as inputs for the selected CNN model and consequently runoff was predicted. Obtained findings showed that projected rainfall changes in 2021-2040 compared to the base period in scenarios of RCP2.6, 4.5 and 8.5 will be +14, +11, +6% in CA, +8, +1, +2% in CSA and +3.7, -1, -2.6% in HT regions, respectively. Whereas, maximum discharge in CA climate in scenario RCP2.6 is projected to raise about 18%, in the HT climate shows a reduce of about 5% in RCP8.5 and in CSA will decrease by about 5% in RCP2.6. Considering the effect of climate as well as seasonal changes in each region on the amount and direction of the climate change impacts on meteorological and hydrologic variables changes, assessing climate change impact in each region is necessary to extract adaptation strategies in water resources management. [ABSTRACT FROM AUTHOR]

In this study, two different initial concentrations of Chlorella vulgaris were injected into two types of dairy wastewater (referred to as wastewater and effluent, respectively) at a percentage of 25, 50, and 75% (v/v), and nutrient removal, microalgae growth and lipid accumulation were examined throughout cultivation (wastewater = before purification and effluent = after Purification). Different concentrations of injected algae, the type of applied wastewater, and different dilution ratios had an important effect on nutrient removal and microalgae growth. The highest amount of nutrients and algal cell number in the initial dose of algae (13 million cells/ml) and mediums of effluent and in wastewater related to dilutions (25, 50, and 75%) respectively. Concerning lipid accumulation in Chlorella vulgaris, the highest concentration was observed in effluent and wastewater at a dilution of 50% and 75%, respectively. In general, it can be concluded that wastewater is more suitable than effluent for lipid production. The aim of this study is production biofuels by biomass and low cost. [ABSTRACT FROM AUTHOR]

The shortage of freshwater and salinization are considered two major development problems in arid and semi-arid regions. The growth of population, development of industry and agriculture, and climate change cause over-extraction of groundwater resources; consequently, the quality and quantity of groundwater decreased, especially in the arid and semi-arid areas. The present study investigates the reasons for salinization of the Kashan aquifer. In this study, 53 observation wells located in the aquifer were examined for qualitative study. A total of 80 samples were collected from selected wells over a period of 5 years (2005–2009) and analyzed for 9 chemical parameters (electrical conductivity (EC), pH, total dissolved solids (TDS), sodium (Na+), potassium (K+), calcium(Ca2+, magnesium (Mg2+), chlorine (Cl−), and bicarbonate (HCO−3)). Groundwater table study shows that the direction of groundwater flow throughout the aquifer is often from the west to the east of the aquifer, except for the northeastern part of the aquifer, where a backflow from the northeast (salt lake) into the aquifer is visible. Results of ion analysis in different areas of the aquifer indicate the occurrence of upconing phenomenon in the center and south regions and the occurrence of saline water intrusion phenomenon in northeast regions. To simulate the condition of the Kashan aquifer for the next 50 years, a model of the quantity and quality of the aquifer was developed using the SEAWAT code. According to the results, the salinization of the Kashan plain aquifer should occur due to two main reasons: irregular groundwater extraction and upconing phenomenon and the intrusion of saline water from the salt lake towards the aquifer. The Kashan aquifer salinization forecast results show that the continuation of the current pumping activities for the next 50 years should increase the numbers of wells affected by salinity. Considering the critical situation of the Kashan aquifer and the existing serious threats, serious decisions and measures for the proper management of groundwater and aquifer protection are vital. [ABSTRACT FROM AUTHOR]

This document is a correction notice for an article titled "An Empirical Relation for Estimating Sediment Particle Size in Meandering Gravel-Bed Rivers." The notice acknowledges errors in the original publication and provides a list of corrections made throughout the article. These corrections include capitalization changes, clarifications of abbreviations, edits to sentences and figures for clarity, and updates to references. The authors assure that these corrections do not affect the scientific conclusions of the article. [Extracted from the article]

Population growth and increasing demand for water have posed a significant challenge to access to safe water resources. Climate change and land use in the not-too-distant future add to the complexity of this challenge. Therefore, it is essential to achieve reliable methods for predicting changes in aquifer storage to plan for the sustainable use of groundwater resources. This study aimed to investigate the management, protection, and sustainable use of groundwater resources under climate change and land use change conditions. In this regard, groundwater supply and demand in one of the important plains in Iran (Hashtgerd plain) for 2020 as the base year was simulated to forecast the trends until 2050 by considering climate change and land use to develop management scenarios to adapt to these conditions using the WEAP model. First, climate change prediction was performed using the HadGEM2-ES model under two emission scenarios, RCP2.6, and RCP8.5, of the IPCC Fifth Assessment Report. The LARS-WG model was used to downscale the climatic data, while land use mapping was performed using Landsat satellite images of 1990, 2005, and 2020 in ENVI 5.3 software. Then, the Markov chain method implemented in TerrSet software was used to model land use change for 2050. The effect of climate change and land use on the decrease of groundwater level was then simulated using the MODFLOW model for the period 2020–2050. In order to manage the water allocation in the area, the information obtained from MODFLOW was transferred to the WEAP model using Link Kitchen interface software. The effects of various management scenarios such as increasing irrigation efficiency, reducing the loss of drinking water distribution networks, and allocating water from the transmission line were evaluated on the adaptation to climate change and land use for a 30-year period. The results showed that with the simultaneous consideration of climate change and land use in the most critical state, the average drop in groundwater level would reach 58 m during the study period, and aquifer reserves will be reduced by more than 50%. The evaluation of management scenarios showed that their implementation not only will protect aquifer reserves but, in addition to meeting 100% of the water needs, will result in sustainable exploitation of groundwater resources. [ABSTRACT FROM AUTHOR]

In this study, after simulating 5 years of saltwater intrusion with SEAWAT package in Astaneh–Kouchesfahan coastal aquifer, Iran, 19 strategies, including managerial, structural, and combined strategies, were investigated to reduce the saltwater intrusion. Since managerial solutions cause users' dissatisfaction and structural solutions increase the costs, two-player game theory was used to identify the most appropriate solution. According to the results obtained from game theory, the two strategies of implementing artificial recharge and the construction of an underground dam had the greatest impact on preventing the saltwater intrusion with the highest satisfaction of stakeholders, and these strategies decreased the extent of saltwater intrusion into the aquifer from 740 m by 150 and 300 m, respectively, after 5 years. Therefore, the combined simulator–optimizer method presented in this study can be used to evaluate various solutions, and the most appropriate solution can be proposed with the lowest cost and maximum satisfaction for the sustainable management of coastal aquifers. [ABSTRACT FROM AUTHOR]

Golestan Dam Lake is located 12 kilometers east of Gonbad City and was constructed in 1379. The volume of the Golestan Dam reservoir is 52 million cubic meters and its area is 1500 hectares, which was built for the purposes of agricultural and aquaculture operations.. The present study on phytoplankton biodiversity and its relationship with the primary productivity of the Golestan Dam reservoir was conducted from April to July 2019. Furthermore, water quality parameters such as transparency, pH, alkalinity, free carbon dioxide, air and water temperature, dissolved oxygen, primary productivity, conductivity, nitrate-nitrogen, and orthophosphate were analyzed along with qualitative and quantitative estimation of phytoplankton. The results indicated that the average primary productivity or gross primary production (GPP) was 0.399 ± 0.081 gcm3h-1, Net Primary Production (NPP) (0.307±0.061 gcm3h-1) and Community Respiration (CR) 0.094±0.024 gcm3h-1 in the surface. Algae in freshwater have numerous environmental functions and are based upon the recycling of nutrients. Totally 73 species of phytoplankton belonging to different taxonomic group were identified which belonges to 32 genera. Among these 32 genera,12 belongs to Cyanophyceae,8 belongs to Chlorophyceae, 10 belongs to Bacillariophyceae and 2 genera belonges to Euglenophyta. On the basis of mean primary productivity, the fish production potential of reservoir Golestan Dam showed considerable scope for the enhancement of current average production. [ABSTRACT FROM AUTHOR]

In the present study, the spatiotemporal evaluation of the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) satellite precipitation product is performed in capturing meteorological drought over different climatic regions of Iran. The performance of the product as a high spatial resolution dataset in monitoring drought is evaluated against the 68 meteorological stations from short to long scale (i.e., SPI1, SPI3, SPI6, SPI9, and SPI12) in the period of 1987 to 2017. Besides, the capability of the CHIRPS in detecting drought events is assessed in different drought classes. The results suggest that the climate type, the time scale, and the drought class affect the quality of the CHIRPS performance. The CHIRPS offers the best performance in the detection of all drought events with SPI < − 1 over the SPI1 (0.69 < POD < 0.85). However, the product provides the worst performance for SPI12 (0.50 < POD < 0.70). At the country level, the highest agreement between the CHIRPS- and observation data-based SPI is found over the SPI6 (CC = 0.56), while the lowest is observed over the SPI12 (CC = 0.47). Based on the temporal evaluation, the G6 (0.18 < CC < 0.44, 1.06 < RMSE < 1.28) and G8 (0.17 < CC < 0.43, 1.06 < RMSE < 1.29) regions located in the southern coast of the Caspian Sea have an inadequate performance. However, the southern parts (G4 region) (0.38 < CC < 0.65, 0.83 < RMSE < 1.27) and the northwestern area (G3 region) (0.53 < CC < 0.62, 0.87 < RMSE < 0.97) of the country offer the best performance. The spatial evaluation describes the high accuracy (CC > 0.7, RMSE < 0.5) in some regions, including the western parts of G1, the northern area of G3, and the southern parts of G4. The research findings provided an important opportunity to advance the understanding of drought monitoring over the different climatic regions based on the high-resolution satellite precipitation products. [ABSTRACT FROM AUTHOR]

User churn is an important issue in online services that threatens the health and profitability of services. Most of the previous works on churn prediction convert the problem into a binary classification task where the users are labeled as churned and non-churned. More recently, some works have tried to convert the user churn prediction problem into the prediction of user return time. In this approach which is more realistic in real world online services, at each time-step the model predicts the user return time instead of predicting a churn label. However, the previous works in this category suffer from lack of generality and require high computational complexity. In this paper, we introduce ChOracle, an oracle that predicts the user churn by modeling the user return times to service by utilizing a combination of Temporal Point Processes and Recurrent Neural Networks. Moreover, we incorporate latent variables into the proposed recurrent neural network to model the latent user loyalty to the system. We also develop an efficient approximate variational inference algorithm for learning parameters of the proposed RNN by using back propagation through time. Finally, we demonstrate the superior performance of ChOracle on a wide variety of real world datasets. [ABSTRACT FROM AUTHOR]

Climate change exerts a considerable impact on the hydrological cycles. Relying on the Long Ashton Research Station-Weather Generator (LARS-WG) statistical model and the Soil & Water Assessment Tool (SWAT), the present study discusses the effects of climate change and gabions on sediment yield of Dehbar drainage basin, Khorasan Razavi Province, Iran, over the next three decades. First, meteorological data were generated for the study period by calibrating the LARS-WG for the basin. Then, meteorological data for the 2020–2050 interval were downscaled using the Hadley Centre Global Environment Model version 2 (HadGEM2) under three Representative Concentration Pathway scenarios, namely RCP8.5, RCP4.5, and RCP2.6. The SWAT was then used to investigate the effects of climate change on runoff and sediment transport in the drainage basin. LARS-WG results were suggestive of a decline in precipitation and a rise in temperature by 2050. The SWAT calculated runoff variations at −21.8%, −17.5%, and −17.1% and sediment yield variations at −4.6%, +9.3%, and +3.1% under RCP8.5, RCP4.5, and RCP2.6, respectively. Removing gabions increased the sediment load by 57% at the basin outlet. [ABSTRACT FROM AUTHOR]

Flooding in urban area affects the lives of people and could cause huge damages. In this study, a model is proposed for urban flood management with the aim of reducing the total costs. For this purpose, a hybrid model has been developed using SWMM and a quasi-two-dimensional model based on the cellular automata capable of considering surface flow infiltration. Based on the hybrid model outputs, stormwater management measure scenarios are proposed. In the next step, a damage estimation model has been developed using depth-damage curves. The amount of damage has been estimated for the scenarios in different rainfall return periods to obtain the damage and cost- probability functions. The conditional values at risk are estimated based on these functions which are the basis of decision making about the stormwater management scenarios. The proposed model is examined in an urban catchment located in Tehran, Iran. In this study, five scenarios have been proposed on the basis of different stormwater management measures. It has been found that the scenario of using permeable pavements results in the lowest risk. The proposed model enables the decision makers to choose the best scenario for the stormwater management with the minimum cost taking into account the risk associated with each scenario. [ABSTRACT FROM AUTHOR]

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]

Identification of the uncertain parameters, which affecting on the qualitative behavior of the aquifer, and determining their effect on the uncertainty of the simulated nitrate concentration (NC) is one of the major challenges in the qualitative monitoring of aquifers. In this study, in order to determine the quantitative amount of uncertainty related to the simulated nitrate, an approach based on a hybrid of Groundwater Modeling System (GMS) model and Fuzzy Vertex Method (FVM) method was developed using the developed code for the relationship between aquifer simulation model and MATLAB environment. In this model, hydraulic conductivity, NC in aquifer recharge sources, longitudinal dispersivity coefficient, and specific storage parameters were considered as uncertain parameters in the distributed simulation model of the Ardabil aquifer. In the proposed approach, first the quantitative and qualitative (QQ) model of the aquifer was prepared using the GMS model and calibrated. Then, using the FVM method and developed MATALB code, the uncertain values appropriate for each of the aquifer active cells were determined. The results obtained from the monthly NC uncertainty show that with increasing the level of uncertainty, the uncertainty of the simulated NC increases significantly. For example, can be mentioned a 14-fold increase in the number of cells with variation of NC less than 10% in the September month. Also, the lowest and highest variation in the deterministic amount of NC is related to the months of Nov. and Sep. with concentration variations equal to [− 8.5, 8.35] and [− 23.43, 19.8] mg/L, respectively. The findings of this study show that the application of at least 10% uncertainty in the deterministic values of the simulated NC is necessary to provide a suitable view for quality monitoring of aquifer. A quantitative amount of monthly uncertainty in areas with nitrate concentrations greater than 50 mg/L indicates that the amount of uncertainty in these areas is higher than areas with nitrate concentrations less than 50 mg/L. This leads to errors in the monitoring of contaminated areas to eliminate contamination and quality restoration. Also, centralization of uncertainty is mainly concentrated in the northeastern, western and southwestern parts of Ardabil plain and the severity of uncertainty in the mentioned areas increases with the intensification of uncertainty and continues to the central areas. Finally, it must be said that hydraulic conductivity and NC in aquifer recharge sources, respectively, play the most important role in creating uncertainty and is necessary to be considered in the NC simulation models. [ABSTRACT FROM AUTHOR]

Drought is a natural phenomenon that causes a lot of damages annually in various sectors, including agriculture and natural resources. The aim of this study is to evaluate the influence of meteorological drought index on vegetation index. For this purpose, the standard precipitation index (SPI) as a meteorological drought index is calculated using the precipitation data of 28 meteorological stations located on the area of Lorestane province, Iran, during the years 1987-2017. Then, the vegetation condition index (VCI) is computed using normalized difference vegetation index (NDVI) images that obtained from MODIS images of Terra satellite during 2000-2017. Dry, normal, and wet years were obtained based on the SPI results for 2008, 2013, and 2016, respectively. SPI and VCI were correlated using Pearson's correlation method. The results of the relationship between VCI and SPI showed that the highest Pearson correlation coefficient related to 9-month SPI in November was equal to 0.64. Multivariate linear regression was also performed between SPI and VCI, and the results showed that SPI was significantly correlated with VCI at 5% level over a period of 9 and 12 months. Finally, a confusion matrix was used to evaluate the compliance of the SPI and VCI drought classes. Results showed that the VCI had the highest compliance in the moderate drought class with SPI. [ABSTRACT FROM AUTHOR]

Groundwater quality management is based on understanding the spatial distribution of parameters in when assessing the suitability of groundwater for use. In this study, different interpolation methods were evaluated in two shallow aquifers according to their hydrogeological characteristics. After initial data processing, 24 deterministic and geostatistical interpolation methods were used with linear and nonlinear relationships. These included: the inverse distance weighted method; the ordinary kriging; the lognormal ordinary kriging (Log_OK); the universal kriging; the disjunctive kriging; the empirical Bayesian kriging; the simple kriging; natural neighbor; the trend surface; and the Spline methods were compared. The spatial distribution of the total dissolved solids parameter was assessed in the Lenjanat and Babol–Amol shallow aquifers with different hydrogeological characteristics. The seven error criteria were used for verification in cross-validation of all sampling wells. The nonlinear Log_OK method produced better results in the Lenjanat and Babol–Amol aquifers with 57 and 71% of error criteria, respectively. Consequently, the non-linear Log_OK method had promising performance in both shallow aquifers with different hydrogeological characteristics. [ABSTRACT FROM AUTHOR]

Distributed modeling provides for mapping of spatial and temporal patterns of highly stressed regions, and it offers local solutions to reduce stress in aquifers. In this study, the groundwater stress index (GWSI) is evaluated based on the groundwater footprint index over the Varamin aquifer in Iran. Using ArcGIS software, all necessary layers were produced and then input into the Groundwater Modeling System software to evaluate GWSI. The results show that distributed modeling offers a more accurate assessment of GWSI than water budget analysis. The minimum and maximum values of the GWSI calculated by the distributed model are 2.4 and 1.4 times, respectively, higher than those values obtained in previous studies. Besides, a significant agreement was observed between highly stressed areas and agricultural land use. Furthermore, the results obtained from comparison between stress pattern and land subsidence indicated that only 10% of the area under subsidence was caused by groundwater stress. Applying appropriate scenarios in the future can be useful to reduce water stress and its increasing trend. [ABSTRACT FROM AUTHOR]

Satellite precipitation products are important data sources in different spatial resolutions, time scales, and spatio-temporal coverage. In this study, the Climate Hazards Group InfraRed Precipitation with Station (CHIRPS) satellite precipitation product with a high spatial resolution (0.05°) is evaluated in the period of 1987 to 2017 over different climate regions of Iran. The accuracy of the satellite product is compared with the 68 ground-based meteorological stations over different time scales (i.e., daily, monthly, and annual) and precipitation classes. Results show that the performance of CHIRPS depends on the time scale, precipitation depth, and climate type. The best performance of the product (CC = 0.80, FRMSE = 0.57, NSE = 0.63) across the country is observed in the annual time scale, while the monthly product offers the best performance in the regional scale. The product provides inadequate performance (CC = 0.34, FRMSE = 5.72, NSE = − 0.2) in daily time scale across the country and most of the climatic regions. The product is found to be most accurate in the south and southwest of the country, while the lowest performance is observed over the Caspian coast. The CHIRPS satellite provides the best performance in detection of no/tiny precipitation (POD > 0.90) and the worst performance in light and low, moderate precipitation (POD < 0.10). It is expected that the findings of the current study can be used to manage the water resources and mitigate the disaster at the national level. [ABSTRACT FROM AUTHOR]

Drought is a type of destructive hydro-climatic disaster that has a significant impact on agriculture and natural resources. Meteorological drought features, including severity, duration, and peak, exhibit various patterns in different climatic regions and geographical conditions. Several indices have been developed to assess the drought potential of different areas across the world, among which the drought hazard index (DHI) is one of the most commonly employed for semi-arid and the flat regions. This study investigates the effects of the elevation and precipitation on DHI, which has received little attention in previous studies. For this purpose, DHIs were computed for 15 stations located at different elevations of the study area over 31 years by considering the occurrence of various drought classes with different weights. The results showed that the elevation and mean precipitation both have inverse effects on the DHI in the study area, which means that the DHI increases when the elevation and mean precipitation are low. The results of the estimation of the DHI for three different periods (i.e., 6, 9, and 12 months) revealed that a 9-month period is optimum for DHI estimations in terms of the reliability of the results. [ABSTRACT FROM AUTHOR]

This study aimed at investigating the effect of grain roughness and bed-load transport on erodible beds friction coefficient (f) in a laboratory flume of 8 m long and 25.5 cm wide. Experiments were carried out at slopes 2, 3 and 5% for an erodible bed consisting of uniform grains with the median diameter of 1.7, 3.3 and 8.2 mm. The maximum dimensionless discharge of the bed-load transport was obtained equal to 0.30. Conducting the experiments in uniform bed material and with the use of empirical relations, friction factor caused by bed roughness (fc) was obtained and the resistance coefficient caused by the bed-load transport (fm) was calculated using the linear theory. By analyzing 130 data from the experimental results of this research and experimental data gathered by Recking et al. (J Hydraul Eng 134(9):1302–1310, 2008) it was realized that at the slopes 5% or more, the frictional resistance caused by the bed-load transport (fm) had more contribution on the total friction resistance f. Also the resistance friction caused by the grains roughness had more contribution at small slope so that in the range of fc/f > 0.6, about 90% of the data was placed at slopes 2–3%, while in the range of fc/f< 0.3, about 90% of the data was placed at slopes of 5–9%. By dimensional analysis, non-dimensional parameters influencing fm were identified and an empirical equation was proposed for fm and validated by experimental results of the previous studies. The accuracy of the relation proposed for prediction of fm was acceptable. The sensitivity analysis of the effective parameters in the proposed equation showed that the Froude number and slope had the greatest effect on the frictional resistance caused by the bed erosion (fm), respectively. [ABSTRACT FROM AUTHOR]

Modeling and prediction of bed loads is an important but difficult issue in river engineering. The introduced empirical equations due to restricted applicability even in similar conditions provide different accuracies with each other and measured data. In this paper, three different artificial neural networks (ANNs) including multilayer percepterons, radial based function (RBF), and generalized feed forward neural network using five dominant parameters of bed load transport formulas for the Main Fork Red River in Idaho-USA were developed. The optimum models were found through 102 data sets of flow discharge, flow velocity, water surface slopes, flow depth, and mean grain size. The deficiency of empirical equations for this river by conducted comparison between measured and predicted values was approved where the ANN models presented more consistence and closer estimation to observed data. The coefficient of determination between measured and predicted values for empirical equations varied from 0.10 to 0.21 against the 0.93 to 0.98 in ANN models. The accuracy performance of all models was evaluated and interpreted using different statistical error criteria, analytical graphs and confusion matrixes. Although the ANN models predicted compatible outputs but the RBF with 79% correct classification rate corresponding to 0.191 network error was outperform than others. [ABSTRACT FROM AUTHOR]

In this study, MIKE 3 model was used to simulate flow pattern and salinity distribution in Urmia Lake. About two decades ago, a causeway was constructed in the lake. The causeway has a 1.25-km opening and divides the lake into northern and southern basins. To perform the simulation, different influential variables such as the discharge of inflow rivers, wind speed, variation in water density, bed roughness, air temperature, relative humidity, cloud coverage, and heat flux through water surface were taken into account. Using the available water level data, salinity, and current velocity, the numerical model was calibrated and validated. Results revealed that the northern part of the lake was saltier due to the negligible entrance of fresh water into the northern part as well as the construction of causeway which restricts water exchange between the northern and southern parts of the lake. Results also showed that density-driven currents are dominant and that the fresher surface water layer in the southern part moves north and circulates counterclockwise in the northern portion of the lake, increasing water salinity and density. This water then moves to deeper layers and circulates back to the southern part. [ABSTRACT FROM AUTHOR]

Scouring is one of the major threats to the stability of bridge abutments constructed over rivers. The present study investigated the usefulness of abutment slots in reducing the scour depth around bridge abutments with vertical walls, experimentally. Nine experiments with no slot and hundred experiments with slots were conducted in clear water conditions. Four subcritical flow conditions (Froude number less than 1) were investigated. For each flow condition, 25 different slot models having different sizes, and vertical and horizontal positions were considered. The results indicated that the slots having heights equivalent to half of the flow depth are more effective in reducing scouring if they are located closer to the bed. Increasing the slot height improves the performance. The best performance is achieved when the slot begins from the water surface and extends below the bed (equal to the scour depth in the model without the slot). Further, the results showed that the greater the distance of the slot is from the abutment nose and closer it is to the channel wall, the more effective the slot would be. Therefore, the most effective slot model is the model in which the slot height equals the distance from the water surface to below the bed, and when it is attached to the channel wall. For different slot models, in different flow conditions, the percentage of reduction of scour depth varies from 20 to 100%. [ABSTRACT FROM AUTHOR]

This paper introduces a 'collocated discrete subdomain meshless method' to solve shallow water equations for free-surface flows with conservation of sediment mass. The computational domain in the method is discretised by distributed nodal points. Shape functions are made using the moving least-squares method for efficiency and simplicity. A number of collocation points, independent of nodal points, are used to form the specified residual function. The sum of residuals at the collocation points for each subdomain is zero in the problem domain and boundaries. In addition, boundary conditions are readily enforced. The model was verified by comparing results of simulated and physically modelled dam-break flows. There was good agreement between the analytical solution and experimental measured data, and a high convergence rate and efficiency were achieved. The method appears to have significant potential for investigating a variety of problems concerning coupled flow with sediment transport. [ABSTRACT FROM AUTHOR]

Damage detection in concrete gravity dams using Hilbert-Huang Method, as one of the most common signal processing techniques, is studied in this research. After considering a typical geometry for dams, damage is modelled by a reduction in the modulus of elasticity in the dam's body (in three levels of damage) and in different areas of the structure. The dam is excited by a horizontal earthquake and the primary natural frequencies of the dam are calculated by applying Hilbert-Huang Method to the measured response, which is the acceleration of five points in the system. Based on the changes in the frequencies of the damaged and undamaged structure, a parameter, called relative frequency error, has been introduced. The results show that the proposed criterion used in this study can not only properly identify the location of damage but also predict the severity of the structural damage in concrete gravity dams accurately. [ABSTRACT FROM AUTHOR]

This study aimed to investigate some key aspects of the reproductive strategy of Ocypode rotundata Miers, 1882 from southwest beaches of Qeshm Island, Persian Gulf, Iran, by providing information regarding its sex ratio, sexual maturity, spawning period and fecundity. Samples were taken monthly, from February 2015 to January 2016. Size at the onset of morphometric maturity was estimated at 38.57 mm carapace width. The overall sex ratio (males/females) was observed as 1.13 : 1.00. On monthly based analyses, the sex ratio showed no significant differences, although a significant deviation was observed toward males in the larger size classes. According to the gonadosomatic index (GSI), gonad maturity and occurrence of ovigerous females, the main breeding season occurs from March to October, with a remarkable peak in June. Fecundity ranged from 24 152 to 10 5287 eggs per individual, with a mean value of 52 389 ± 25 660. The ratio between fecundity and carapace width varied from 632 to 2044 eggs/mm (mean: 1198 ± 472 eggs/mm) and fecundity relative to total mass varied from 771 to 1965 eggs/g (mean: 1336.66 ± 425.43 eggs/g). The reproductive output ranged from 1.04 to 3.78 (mean: 2.35 ± 0.90). The shape of the egg was spherical and it included 6 stages of growth, ranging from fully filled with yolk to fully occupied by the embryo. We concluded that reproduction in O. rotundata is seasonal, and that spawning occurs in an appropriate period to ensure maximum survival of the offspring. The fecundity of O. rotundata is higher than that of other species of Brachyura, with GSI variations being related to temperature. Overall, the results of this study provide relevant information for the reproduction in general and the breeding seasons of O. rotundata, whicht can be useful for conservation and management policies aimed at preserving the biodiversity of ghost crabs along the Persian Gulf’s sandy shores. [ABSTRACT FROM AUTHOR]

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This experiment was conducted to illustrate the effect of dietary taurine levels on Persian sturgeon, Acipenser persicus (mean weight of ~35 g) fed plant-based diet. A basal diet containing low level of fishmeal (19%) was formulated containing 0.05% endogenous taurine (control diet). To this diet were added five levels of exogenous taurine: 0.25 (0.25T), 0.5 (0.5T), 0.8 (0.8T), 1.2 (1.2T) and 1.6% (1.6T). These diets were fed to the experimental fish for 42 days. Results showed that growth performance decreased and food conversion ratio increased as dietary taurine increased, although no significant difference was observed between the control and 0.25T treatments. Increased dietary taurine led to increased carcass moisture and decreased carcass lipid percentages. Feed intake was significantly and negatively correlated with dietary taurine. Carcass taurine content significantly increased with dietary taurine elevation up to 1.2% and then decreased. Hepatic taurine content showed a significant increase in 0.25T treatment and then decreased along with dietary taurine elevation and reached the control values at 1.6% taurine level. Dietary taurine elevation led to more hepatic damages compared to the control. In conclusion, although within the range reported for other studied fish, the tested taurine levels in this study might be supra-optimal causing adverse effects in Persian sturgeon and further study with lower taurine levels is encouraged. [ABSTRACT FROM AUTHOR]

Seaweeds contains different types of polysaccharides with high abilities. The aim of this study was to determine the potential of fucoidan polysaccharides for wound-healing properties. Fucoidans of two species of Padina (P. tetrastromatica and P. boergesenii), collected from the Persian Gulf northern coastal area, were extracted and analyzed using high-performance anion-exchange chromatography. Purified fucoidans were used to prepare a 2% topical ointment. Under aseptic conditions, two identical paravertebral full-thickness skin wounds (either by burn or excision) were made in 40 anesthetized male rats allocated into 4 groups. Either fucoidan ointments or the vehicle (ointment base) were applied to rats' wounds twice daily for 14 days. In addition to the examination of wound area reduction (days 3, 7, 10, and 14) and histopathological assays (days 7 and 10), tissue specimens were taken to the laboratory. Fucoidans obtained from both seaweeds induced significant wound area reduction compared to the vehicle at some time points after treatment. Histopathological examinations showed improvement in some healing signs including angiogenesis, collagen fiber formation, and epidermis formation. In conclusion, both species of Padina have significant wound-healing effects and fucoidan polysaccharides are the active constituents for this healing property. However, fucoidan obtained from P. boergesenii showed superior effects in this regard. [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]

This study was conducted to record best towing duration for bottom trawl surveys to stock assessment in the Persian Gulf. Shannon-Wiener, Margalef and evennes index were calculated for four towing duration (60, 90, 120 and 150minutes) in fishing grounds of Persian Gulf. A stratified random procedure was used for the survey sampling. The mean CPUA differed significantly with towing duration (P< 0.05) for the T. lepturus. The mean Shannon-Weiner diversity index differed significantly between four towing duration with higher Shannon- Weiner diversity index for 120minutes (2.81±0.44) (F=5.38; P=0.03. The mean CPUA differed significantly between towing durations with lowest CPUA at 150 minutes (P<0/05). Results showed that 120minutes towing duration was the best for scientific surveys. 150 minutes towing duration was not suitable for scientific surveys in the Persian Gulf. The present research provided the first comprehensive study on the effect of trawl duration on diversity index and CPUA in Persian Gulf. [ABSTRACT FROM AUTHOR]

The spatial and temporal variations of finfish bycatch assemblages cutlassfish trawl were compered in two fishing area (Hormozgan and Bushehr waters). Data were collected on board of commercial vessels in the fishing grounds of Trichiurus lepturus since May 1st 2009 to November 2010. There was a significant difference in the bycatch assemblages between Bushehr and Hormozgan fishing grounds. SIMPER showed that six species contributed 65% of the biomass of the bycatch assemblages between two fishing areas: Nemipterus japonicus (30.5%), Ilisha melastoma (12.5%), Saurida tumbil (8.5%), Argyrops spinifer (6%), Dasyatis bennetti (4.5%) and Netoma thalassinus (4%). Differences appeared for the temporal structures of bycatch assemblages in fishing grounds of Bushehr. SIMPER showed that eight species contributed 69.3% to the dissimilarity of the biomass of the bycatch assemblages between fishing seasons. These species were S. tumbil (17.3%), I. melastoma (16.3%), N. japonicus (13.3%), Carangoides malabaricus (17.2%), Rachycentron canadun (6.3%), Upeneus sundaicus (3.5%) D. bennetti (3.5%) and Epinephelus coioides (3.2%). [ABSTRACT FROM AUTHOR]

A study was conducted to investigate the effects of dietary citric acid (CA) (0, 1%, 2% and 3%) on the calcium (Ca) and phosphorus (P) contents of muscle, scute and serum of Beluga ( Huso huso) juveniles (25.1±1.9 g). After 8 weeks of feeding on the experimental diets, the Ca and P contents of muscle, scute and serum were measured. The results revealed that the addition of 2% and 3% CA significantly increased the Ca and P contents of muscle and serum. Dietary CA had no effect on the Ca content of scute, but the P content of scute was significantly higher compared with additional 1% CA and the control. These results indicate that the addition of CA to the diet of Beluga increased the bioavailability of Ca and P, thereby increasing muscle and scute mineralization. [ABSTRACT FROM AUTHOR]

This paper reports an improved version of the numerical method used in a previous study on the dynamic simulation of purse seine gear in three dimensions. The improvement is achieved by refining the mass-spring model to take into account both the drag coefficient as a function of the attack angle and Reynolds number as applied to the setting operation of the purse seine gear. The validity of the numerical simulation is assessed by comparing the measured and calculated values for the sinking depth of the net. The numerical simulation is used to examine the sinking performance of the different designs in which large meshed-panels and netting materials are used together in the main body section of the netting. The results indicate that, compared to the prototype net, nets bearing larger mesh panels require more sinking depth with much more pronounced operational depth at corresponding times of the fishing operation when heavier netting material is used. Moreover, in the new net designs, lower tensile forces are exerted on both ends of the pure wire during pursing. The new net constructions with regard to the operational depth represent alternatives that may reduce the potential problem of frequent failed setting of the tuna purse seine gear. [ABSTRACT FROM AUTHOR]