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The hyporheic zone represents the interface between surface and subsurface flow. An experimental investigation was conducted in a laboratory flume featuring a maximum flow rate of 50 L per second, utilizing artificial grass completely submerged in water. Two sets of experiments were carried out, one with vegetation cover and the other without. The findings revealed that vegetation cover led to a reduction in hyporheic velocity, whereas the absence of vegetation increased hyporheic velocity. The study also noted that the absence of a hyporheic zone in vegetation, compared to gravel, could be attributed to the formation of a separation zone. Additionally, it was observed that vegetation cover facilitated the supply of more nutrients around the divide line, owing to upwelling flows from both upstream and downstream directions. Given the limited dataset, Soft Computing (SC) techniques, namely Wavelet-GEP (WGEP) and Gene Expression Programming (GEP), were employed to formulate mathematical equations for estimating hyporheic velocity under steady-state conditions for a given discharge. These equations, incorporating hydraulic and geomorphic variables, proved effective in estimating hyporheic velocity under stable bed conditions during steady flow. The models were trained and tested using 70% and 30% of the collected data, respectively. The performance of the models was assessed using statistical criteria. The results indicated a strong correlation between noise reduction in data and improved performance of the WGEP model compared to the GEP model in estimating velocity. [ABSTRACT FROM AUTHOR]

Bed sills are a kind of grade control structure built at the same level as the river bed to protect it against erosion and to reduce the longitudinal slope of the channel. The aim of the present research was to determine the optimal dimensions of the structure by devising a new methodology to minimize cost and maximize stability, based on the optimization model of the multi-objective non-dominated sorting genetic algorithm (NSGA-II). This is achieved by calculating the width, height and distance between bed sills with these stability and cost objectives in mind. The NSGA-II algorithm is applied to solve the problem, and a set of Pareto points is obtained. The results are verified by considering the bed sills of the River Madarsoo in Iran and the River Plima in Italy, and comparing the results with those obtained using the Branch-and-Bound (B-and-B) algorithm. The results indicate that the cost and stability could respectively be improved by up to 18 and 20% in the River Madarsoo, and up to 18 and 26% in the River Plima, if the NSGA-II algorithm is used. [ABSTRACT FROM AUTHOR]

This pilot study investigates the correlation between psychological stress and antiretroviral therapy (ART) adherence and plasma HIV RNA (viral load) as mediated by psychological flexibility among Black men in the south. Data were collected from 48 HIV-positive, low income Black men. Results indicate a strong positive correlation between perceived stress and psychological inflexibility (adjusted for age and income rs = 0.67; p < 0.001), a negative correlation between psychological inflexibility and ART adherence (adjusted rs = − 0.32; p = 0.03), a negative correlation between perceived stress and ART adherence (adjusted rs = − 0.45; p = 0.006), and a negative correlation between ART adherence and viral load (adjusted rs = − 0.37; p = 0.04). Our findings suggest stress decreases adherence to ART and viral suppression among Black men living with HIV. However, psychological flexibility did not mediate the relationship between stress and treatment adherence. Hair cortisol concentrations were high (mean of 34.2 pg/mg), but uncorrelated with adherence. [ABSTRACT FROM AUTHOR]

The mathematical models prevalently used to represent stem cell proliferation do not have the level of accuracy that might be desired. The hyperbolastic growth models promise a greater degree of precision in representing data of stem cell proliferation. The hyperbolastic growth model H3 is applied to experimental data in both embryonic stem cells and adult mesenchymal stem cells. In the embryonic stem cells the results are compared with other popular models, including the Deasy model, which is used prevalently for stem cell growth. In the case of modelling adult mesenchymal stem cells, H3 is also successfully applied to describe the proliferative index. We demonstrated that H3 can accurately represent the dynamics of stem cell proliferation for both embryonic and adult mesenchymal stem cells. We also recognize the importance of additional factors, such as cytokines, in determining the rate of growth. We propose the question of how to extend H3 to a multivariable model that can include the influence of growth factors. [ABSTRACT FROM AUTHOR]