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A massive use of nitrogen based fertilizers in agriculture is worldwide one of the main causes for nitrate contamination of groundwater. Methods for removing nitrate from aquatic environment through physical and/or chemical processes often turn out to be not applicable because of unaffordable financial resource as well as essential infrastructure lack. On the other hand, biological processes seem to have potentiality to overcome these limitations since they are less expensive and easier to be performed. Accordingly, in the present work, a moving bed biofilm reactor (MBBR) filled with Kaldnes K1 as carrier media was used to remove nitrate from a synthetic groundwater at bench scale. Acetate was used as organic source. Different operational conditions were tested: influent nitrate concentrations of 30, 40, 50 and 60 mg/L; hydraulic retention times of 24, 18, 12 and 8 h; and COD/NO3-N mass ratios of 3.00 and 2.98. Experimental results showed that NO3-N = 60 mg L−1, HRT = 8 h and COD/NO3-N ratio = 2.98 were the optimal operating conditions that allowed achieving a NO3-N removal by 99 % and a COD removal by almost 100 %. Moreover, almost no NO2−-N accumulation and null COD concentration were observed at the optimal operating conditions. An activated carbon filter was placed downstream to remove residual organic compounds prior to disinfection unit, thus avoiding the potential formation of harmful disinfection by-products (e.g. trihalomethanes (THMs)). The MBBR was able to show a rapid recovery whenever the operating conditions were defined as more severe, thus proving that the operating conditions can vary over a wider range. Furthermore, the results showed that the MBBR system can be used effectively as a biological process to remove nitrate from groundwater.

The Authors presented a fascinating research work on the air demand in spillways. The investigation was based on the air demand observations along the spillway tunnel of the Jinping-I dam, in China. Prototypal and 3D numerical model data of the total air demand, Qair, along the spillway tunnel, and of the air discharge along three air ducts installed on the tunnel ceiling were evaluated. These data were then compared with the estimations by a 1D model, as suggested by the Authors, and by some empirical equations from the technical literature. The Authors showed that the 1D model, calibrated by modifying the interfacial shear stress coefficient, gave the more accurate prediction of Qair.

Modelling urban floods is a challenging task because different spatial scales are involved. In current porosity models, space averaging of the urban fabric leads to the concept of porosity. Ordinary Single Porosity (SP) Shallow water Equations (SWE) consider smooth porosity. The Binary Single Porosity (BSP) model generalizes SP models to consider discontinuous porosity

The drainage network of the city of Cossonay (Switzerland) is currently being adapted for future needs. In particular, it is required to drain increased storm discharges due to a population augmentation, and to provide an adequate concept to overcome unfavorable geotechnical conditions. Vortex drop shafts are sewer manholes commonly applied in steep urbanized topographies to connect conduits across large elevation differences. In Cossonay, the existing 48 m high vortex drop shaft, with a diameter of 1.5 m, allowed the storm discharge to flow from the city to a watercourse issued at half of the valley height. The discharge capacity was initially assumed as 4.1 m3/s, but frequent pulsations and choking phenomena implied a reduced effective capacity of around 3.0 m3/s. A new planned vortex drop shaft will collect the supercritical inflows of four collectors in the old City Centre and spill them through a shaft of roughly 120 m height, restituting the flow at the valley bottom. It was pre-designed using FLOW-3D simulations to estimate the hydraulic features of the incoming flows and to predict the hydraulic behavior of the upper elements (before the water enters the shaft). The simulation thus included a novel junction chamber type and the steep inlet channel before the spiral intake. The numerical simulations provided a first layout of the structure that was then validated by physical model tests. The physical model was built at the Laboratory of Hydraulic Constructions (LCH) of École Polytechnique Fédérale de Lausanne (EPFL).

Mutations in the genes encoding for gap junction proteins connexin 26 (Cx26) and connexin 30 (Cx30) have been linked to syndromic and nonsyndromic hearing loss in mice and humans. The release of ATP from connexin hemichannels in cochlear nonsensory cells has been proposed to be the main trigger for action potential activity in immature sensory inner hair cells (IHCs), which is crucial for the refinement of the developing auditory circuitry. Using connexin knock-out mice, we show that IHCs fire spontaneous action potentials even in the absence of ATP-dependent intercellular Ca(2+) signaling in the nonsensory cells. However, this signaling from nonsensory cells was able to increase the intrinsic IHC firing frequency. We also found that connexin expression is key to IHC functional maturation. In Cx26 conditional knock-out mice (Cx26(Sox10-Cre)), the maturation of IHCs, which normally occurs at approximately postnatal day 12, was partially prevented. Although Cx30 has been shown not to be required for hearing in young adult mice, IHCs from Cx30 knock-out mice exhibited a comprehensive brake in their development, such that their basolateral membrane currents and synaptic machinery retain a prehearing phenotype. We propose that IHC functional differentiation into mature sensory receptors is initiated in the prehearing cochlea provided that the expression of either connexin reaches a threshold level. As such, connexins regulate one of the most crucial functional refinements in the mammalian cochlea, the disruption of which contributes to the deafness phenotype observed in mice and DFNB1 patients. SIGNIFICANCE STATEMENT: The correct development and function of the mammalian cochlea relies not only on the sensory hair cells, but also on the surrounding nonsensory cells. Although the nonsensory cells have been largely implicated in the general homeostasis in the mature cochlea, their involvement in the initial functional differentiation of the sensory inner hair cells is less clear. Using mutant mouse models for the most common form of congenital deafness in humans, which are knock-outs for the gap-junction channels connexin 26 and connexin 30 genes, we show that defects in nonsensory cells prevented the functional maturation of inner hair cells. In connexin knock-outs, inner hair cells remained stuck at a prehearing stage of development and, as such, are unable to process sound information.

"On October 23, 2007, the European Parliament approved the ‘Floods Directive’ 2007\/60\/CE (FD), aimed to regulate the procedures for hydraulic risk assessment. One of its most innovative aspects consists in the characterization of flood hazard by multi-scenario hydraulic analyses, based on the estimation of flow velocities and water depths all over the flooded areas. In principle, the accurate evaluation of these parameters would require a complete analysis of the watershed hydraulics, based on two- or even three-dimensional modeling; the latter, however, may hardly be applied to river-scale problems due to its huge computational and input data requirements, so 1D and 2D analyses represent the practical alternatives for fluvial hydraulic investigation. Within this perspective, the systematic comparison between these two modeling approaches provides a valuable help to the user in the confident choice of a tradeoff between complexity and accuracy. The present work discusses a comprehensive comparison between the results of 1D and 2D approaches in the analysis of floods in meandering channels. In particular, both numerical models were applied to a typical river morphology which may be represented by a few shape parameters (e.g. sinuosity, depth\/width ratio, cross-section shape and so on). Conformingly to the common praxis for hydraulic risk assessments, steady flow conditions have been assumed. From the computational point of view, normal-flow framework is considered for the 1D analysis, whereas two-dimensional modeling is performed using CCHE2D, a finite element depth-averaged model developed at NCCHE, the University of Mississippi .. Various channels with different shape parameters (namely sinuosity and depth\/width ratio) are considered, according to their typical values for natural rivers. For each combination of shape parameters, several simulations are performed to produce in-bank and overbank flows. The models results are compared in terms of flow velocity, free surface elevation, shear stress distribution and computed stage-discharge hydrograph. Finally, the values of the minimum freeboard (defined as the minimum distance between water surface and the top of river bank) across the channel bend are evaluated and compared."

A case of a 9-year-old boy with neurofibromatosis of von Recklinghausen and precocious puberty is reported. The patient was referred to us because of an unexplained onset of precocious puberty. Clinical manifestations of neurofibromatosis included multiple café-au-lait spots, skeletal anomalies, progressive impairment of vision and precocious sexual development. CT scan and NMR demonstrated the presence of optic gliomas. The correlation between the lesions of retino-hypothalamic projection and production of the neuroendocrinology mechanism of sexual changes is discussed.