Stenting of the arterial duct is a feasible, safe and effective palliation in newborns with duct-dependent pulmonary circulation, supporting the spontaneous improvement process or promoting significant and balanced pulmonary artery growth for subsequent corrective surgery.
[1] Basic soil properties have long been used to predict unsaturated soil hydraulic properties with pedotransfer function (PTFs). Implementation of such PTFs is usually not feasible for catchment-scale studies because of the experimental effort that would be required. On the other hand, topographical attributes are often readily available. This study therefore examines how well PTFs perform that use both basic soil properties and topographical attributes for a hillslope in Basilicata, Italy. Basic soil properties and hydraulic data were determined on soil samples taken at 50-m intervals along a 5-km hillslope transect. Topographical attributes were determined from a digital elevation model. Spearman coefficients showed that elevation (z) was positively correlated with organic carbon (OC) and silt contents (0.62 and 0.59, respectively) and negatively with bulk density (r b ) and sand fraction (À0.34 and À0.37). Retention parameters were somewhat correlated with topographical attributes z, slope (b), aspect (cosf), and potential solar radiation. Water contents were correlated most strongly with elevation (coefficient between 0.38 and 0.48) and aspect during ''wet'' conditions. Artificial neural networks (ANNs) were developed for 21 different sets of predictors to estimate retention parameters, saturated hydraulic conductivity (K s ), and water contents at capillary heads h = 50 cm and 12 bar (10 3 cm). The prediction of retention parameters could be improved with 10% by including topography (RMSE = 0.0327 cm 3 cm À3 ) using textural fractions, r b , OC, z, and b as predictors. Furthermore, OC became a better predictor when the PTF also used z as predictor. The water content at h = 50 cm could be predicted 26% more accurately (RMSE = 0.0231 cm 3 cm À3 ) using texture, r b , OC, z, b, and potential solar radiation as input. Predictions of ANNs with and without topographical attributes were most accurate in the wet range (0 < h < 250 cm). Semivariograms of the hydraulic parameters and their residuals showed that the ANNs could explain part of the (spatial) variability. The results of this study confirm the utility of topographical attributes such as z, b, cosf, and potential solar radiation as predictors for PTFs when basic soil properties are available. A next step would be the use of topographical attributes when no or limited other predictors are available.
Agricultural terraces are often subject to degradation issues related to water movement. A better understanding of the main hydrological processes that govern surface and subsurface water flow pathways and that are responsible for terrace failure and dry-stone wall collapse is essential for appropriate water resource management and rural landscape maintenance in terraced areas. However, a clear conceptualization of different hydrological functioning related to wall instability issues is still missing. In this study, we monitored a terrace system in a hilly site of central Italy cultivated with vineyards. We adopted a multidisciplinary approach based on soil analysis, different geophysical techniques, hydrological monitoring, high-resolution grid terrain analysis and field experiments (infiltration and flooding tests) aiming to: (i) obtain new information of terrace soil and subsoil structure; (ii) test the hypothesis on wall instability based on the formation of preferential flow and water accumulation behind the wall; and (iii) develop a conceptual model of water circulation in agricultural terraces. Our results indicate that terrace soil was highly heterogeneous, including discontinuities and piping systems that facilitated a rapid infiltration and the development of fast subsurface flow. Groundwater rise did not occur, as observed in other terraced sites, but infiltrated water accumulated behind dry-stone walls, increasing pore water pressure and inducing wall bulging and instability. Our findings provided new field evidences of water circulation and led to the definition of a novel paradigm of hydrological functioning of farming terraced systems for addressing more efficient management and maintenance issues in these vulnerable landscapes. Copyright © 2017 John Wiley & Sons, Ltd
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