General 1-D hydrogeological model for temporal near-surface loess saturation assessment for the needs of radon potential mapping

Radon gas has high mobility and is driven by advection and diffusion with the soil gas throughout connected and water-unsaturated pores and/or cracks in permeable rocks and soils. Hence the radon potential of the area could be dependent on not only geology as a constant source of radon but also from the changes of the saturation state of the ground. The loess complex, characterized by its permeability and usual state of unsaturation, covers 10% of the Bulgarian territory. The study deals with the principles of unsaturated domain modeling. An attempt of generic vertical infiltration model coinciding with the most upper part of loess vadose zone was performed.

Gα13-Mediated β2 Integrin Outside-in Signaling in Neutrophil Migration

Transendothelial migration of neutrophils requires chemoattractant signals and also integrin family of adhesion receptors, particularly the β 2 family of integrins, including Mac-1 and LFA-1. Signals transmitted by G protein-coupled receptors (GPCR) for chemoattractants and cytokines induces inside-out signaling activating the ligand binding function of integrins. Conversely ligand binding to integrins stimulates outside-in signaling, leading to cell spreading, retraction and migration. The heterotrimeric G protein subunit, Gα13, is important for GPCR signaling leading to RhoA activation but also binds to integrins, including β2 integrins to stimulate outside-in signaling. To study the roles of Gα13 in neutrophil migration, we tested the effect of Gα13 knockout on transendothelial migration of neutrophils stimulated by chemoattractant fMIVIL. We demonstrate that transendothelial migration of Gα13 knockout neutrophils was significantly but partially reduced as compared with wild type mice. Transendothelial migration of Gα13 knockout neutrophils is similar to wild type neutrophil migration neutralized with an anti-Mac1 (anti-αm) antibody, and was not further inhibited by the anti-Mac1 antibody, suggesting that transendothelial migration mediated by integrin αmβ2 was predominantly Gα13-dependent. Interestingly, either anti-β2 antibody or anti-LFA1 (anti-αL) antibody appeared to inhibit transendothelial migration of not only wild type neutrophils, but also to a degree, Gα13-knockout neutrophils, suggesting a minor LFA1-dependent but Gα13-independent component of transendothelial migration in addition to the Gα13-dependent transendothlial migration. Furthermore, even though the fibrinogen and ICAM-1 are both β2 ligands, we show that more neutrophils migrated through ICAM-1-coated transwells than fibrinogen-coated transwells, and only ICAM-1-mediated neutrophil migration is Gα13 dependent, suggesting that Gα13-dependent neutrophil migration is selective for certain β2 integrin ligand (ICAM-1). Importantly, Gα13 knockout selectively inhibited the velocity of neutrophil migration on integrin ligand ICAM-1, but had no effect on the directionality of neutrophil migration which requires GPCR-dependent chemoattactant signaling. To understand whether and how Gα13 regulate integrin signaling, we show that Gα13 knockout did not affect the static adhesion of neutrophils to ICAM1, but significantly inhibited neutrophil spreading on ICAM-1. Furthermore, Gα13 bound to β2 integrins in neutrophils adherent on ICAM-1, and this binding was inhibited by the ExE motif peptide MB2mP6 derived from the Gα13 binding site of β2 integrin cytoplasmic domain. MB2mP6 also inhibited transendothelial cell migration similarly as Gα13 knockout. These data suggest that Gα13 plays an important role in promoting β2-integrin dependent neutrophil transendothelial migration mainly by mediating integrin outside-in signaling. Consistent with previous findings of the role of Gα13-dependent outside-in signaling in negative regulation of RhoA in other integrin subtypes, both Gα13 knockout and MB2mP6 abolished the transient inhibition in RhoA during adhesion of neutrophils on ICAM-1. These data suggest that Gα13 mediates outside-in signaling and transient inhibition of RhoA, and thus promotes neutrophil spreading and migration on integrin ligands. To test the role of Gα13 in neutrophil migration in vivo, we showed that neutrophil infiltration in vivo was reduced in leukocyte-selective Gα13 knockout mice using both thioglycolate-induced peritoneal neutrophil infiltration model and LPS-induced neutrophil lung infiltration model in vivo. Furthermore, MB2mP6 inhibited neutrophil infiltration in cardiac tissues in the cardiac ischemia-reperfusion injury model in mice. These data suggest that Gα13-integrin interaction plays an essential role in the integrin-dependent transendothelial migration and is likely to be important in neutrophils' immune and inflammatory functions. Disclosures No relevant conflicts of interest to declare.

Implementation of the Green-Ampt Infiltration Model: Comparative between different numerical solutions

The phenomena of infiltration and the percolation of water in the soil are of fundamental importance for the evaluation of runoff, groundwater recharge, evapotranspiration, soil erosion and transport of chemical substances in surface and groundwater. Within this context, the quantitative determination of the infiltration values is extremely important for the different areas of knowledge, in order to evaluate, mainly the surface runoff. Several types of changes in vegetation cover and topography result in significant changes in the infiltration process, making it necessary to use mathematical models to assess the consequences of these changes. Thus, this article aims to implement the Green-Ampt model using two numerical methods - Newton-Raphson method and W-Lambert function - to determine soil permeability parameters - K and matric potential multiplied by the difference between initial and of saturation - comparing them to the real data obtained in simulations using an automatic rainfall simulator from the Federal University of Goiás - UFG. The Green-Ampt model adjusted well to the data measured from the rain simulator, with a determination coefficient of 0.978 for the Newton-Raphson method and 0.984 for the W-Lambert function.

Rain garden infiltration rate modeling using gradient boosting machine and deep learning techniques

Rain garden are effective in reducing storm water runoff, whose efficiency depends upon several parameters such as soil type, vegetation and metrological factors. Evaluation of rain gardens has been done by various researchers. However, knowledge for sound design of rain gardens is still very limited, particularly the accurate modeling of infiltration rate and how much it differs from infiltration of natural ground surface. The present study uses experimentally observed infiltration rate of rain gardens with different types of vegetation (grass, candytuft, marigold and daisy with different plant densities) and flow conditions. After that, modeling has been done by the popular infiltration model i.e. Philip's model (which is valid for natural ground surface) and soft computing tools viz. Gradient Boosting Machine (GBM) and Deep Learning (DL). Results suggest a promising performance (in terms of CC, RMSE, MAE, MSE and NSE) by GBM and DL in comparison to the relation proposed by Philip's model (1957). Most of the values predicted by both GBM and DL are within scatter limits of ±5%, whereas the values by Philips model are within the range of ±25% error lines and even outside. GBM performs better than DL as the values of the correlation coefficients and Nash-Sutcliffe model efficiency (NSE) coefficient are the highest and the root mean square error is the lowest. The results of the study will be useful in selection of plant type and their density of the rain garden in the urban area.

Applicability of Literature Values for Green–Ampt Parameters to Account for Infiltration in Hydrodynamic Rainfall–Runoff Simulations in Ungauged Basins

This study aimed to evaluate the suitability of literature parameter values for the Green–Ampt infiltration model to be used in hydrodynamic rainfall–runoff simulations. The outcome of this study supports to decide which literature values should be taken if observed data for model calibration is not available. Different laboratory experiments, a plot-scale experiment in the Thiès catchment in Senegal, and a flash flood in the region of El Gouna in Egypt, have been simulated with the 2D shallow water model Hydroinformatics Modeling System (hms) incorporating the Green–Ampt model. For four test cases with available runoff data, the results of the calibrated models were compared to those obtained from average values after Rawls et al. (Journal of Hydraulic Engineering 1:62–70, 1) and Innovyze (Help documentation of XPSWMM and XPStorm, 2). The results showed a clear underestimation of infiltration in two of three considered laboratory experiments, while for a field experiment in Senegal, average values after Rawls et al. (Journal of Hydraulic Engineering 1:62–70, 1) led to a strong overestimation and the ones after Innovyze (Help documentation of XPSWMM and XPStorm, 2) to an underestimation of infiltration. In a case study on flash floods in an ungauged region in Egypt, the values of both sources led to a strong overestimation of infiltration, when the simulation results are compared to observed flooding areas. It can be concluded, that the values after Innovyze (Help documentation of XPSWMM and XPStorm, 2) lead to overall better results than the ones after Rawls et al. (Journal of Hydraulic Engineering 1:62–70, 1). According to the results, the hydraulic conductivity in ungauged areas with bare sandy soil should be reduced by about 90–100 % compared to the value after Rawls et al. (Journal of Hydraulic Engineering 1:62–70, 1).

Effect of urban underlying surface change on stormwater runoff process based on the SWMM and Green-Ampt infiltration model

The acceleration of urbanization has brought significant changes to the urban underlying surface. As a result, the flood disaster caused by stormwater runoff has become increasingly prominent. The infiltration function of the permeable area can lead to flood disasters, but the extent and depth of the effect are still unclear. Therefore, based on the storm water management model (SWMM) and Green-Ampt infiltration model, this paper discussed the effect of improving soil saturated hydraulic conductivity (SSHC) and soil capillary suction head (SCSH) on the stormwater runoff process. The results show that the increase of SSHC and SCSH can significantly reduce runoff and increase infiltration. However, the improvement of SSHC can more effectively alleviate flood disasters compared with the improvement of SCSH. And the change of SSHC has a significant effect on the stormwater runoff with a critical SSHC value while the effect can be ignored. In addition, there is a cross value; when the value of SSHC and SCSH is larger than the cross value, the difference between SSHC and SCSH in reducing runoff duration no longer exists. The critical value and cross value are not constant but change with the change of rainfall intensity.