Magnesium Exposure in Very Preterm Neonates and Adverse Gastrointestinal Outcomes

Preterm birth is the leading cause of perinatal morbidity and mortality, especially among neonates born less than 32 weeks’ gestation. Magnesium sulfate is the standard treatment for seizure prevention in preeclampsia and for fetal neuroprotection in mothers at risk for preterm delivery. However, the consequences of antenatal magnesium exposure on the very preterm neonate’s gastrointestinal tract are not fully established. This study will determine whether elevated magnesium levels in very preterm neonates are associated with adverse gastrointestinal outcomes from birth to 4 months. Specifically, using a prospective cohort design, we will measure magnesium in umbilical cord blood of very preterm neonates at the time of delivery and determine whether elevated levels are associated with feeding intolerance, necrotizing enterocolitis, or spontaneous intestinal perforation. This study may provide evidence for the use of umbilical cord magnesium concentration as a screening tool for risk for adverse gastrointestinal outcomes among very preterm neonates

Sampling errors in rainfall measurements by weather radar

International audienceRadar rainfall data are affected by several types of error. Beside the error in the measurement of the rainfall reflectivity and its transformation into rainfall intensity, random errors can be generated by the temporal spacing of the radar scans. The aim of this work is to analize the sensitivity of the estimated rainfall maps to the radar sampling interval, i.e. the time interval between two consecutive radar scans. This analysis has been performed employing data collected with a polarimetric C-band radar in Rome, Italy. The radar data consist of reflectivity maps with a sampling interval of 1min and a spatial resolution of 300m, covering an area of 1296km2. The transformation of the reflectivity maps in rainfall fields has been validated against rainfall data collected by a network of 14 raingauges distributed across the study area. Accumulated rainfall maps have been calculated for different spatial resolutions (from 300m to 2400m) and different sampling intervals (from 1min to 16min). The observed differences between the estimated rainfall maps are significant, showing that the sampling interval can be an important source of error in radar rainfall measurements

Forest cover influence on regional flood frequency assessment in Mediterranean catchments

The paper aims at evaluating to what extent the forest cover can explain the component of runoff coefficient as defined in a regional flood frequency analysis based on the application of the rational formula coupled with a regional model of the annual maximum rainfall depths. The analysis is addressed to evaluate the component of the runoff coefficient which cannot be captured by the catchment lithology alone. Data mining is performed on 75 catchments distributed from South to Central Italy. Cluster and correlation structure analyses are conducted for distinguishing forest cover effects within catchments characterized by hydro-morphological similarities. We propose to improve the prediction of the runoff coefficient by a linear regression model, exploiting the ratio of the forest cover to the catchment critical rainfall depth as dependent variable. The proposed regression enables a significant bias correction of the runoff coefficient, particularly for those small mountainous catchments, characterised by larger forest cover fraction and lower critical rainfall depth

Vulnerabilità del territorio vesuviano a fenomeni meteorologici attraverso l’analisi quantitativa di fattori geologici ed antropici.

In questo lavoro viene descritta l’applicazione al territorio vesuviano di una metodologia di analisi geomorfologico-quantitativa multiparametrica da DTM (Digital Terrain Model) di dettaglio (5x5m) in ambiente GIS, utilizzando procedure di analisi e tecniche di valutazione della vulnerabilità a fenomeni meteorologici che tengano conto della complessità dell’assetto geologico, geomorfologico, urbanistico ed economico dell’area. Il risultato del lavoro è stato la realizzazione di mappe di vulnerabilità idrogeologica prodotte tenendo conto delle mutue relazioni tra fattori territoriali ed antropici. L’obiettivo di questo studio è stato sviluppare un sistema di analisi utile alla valutazione del rischio idrogeologico ed al suo controllo e prevenzione, considerato che negli ultimi anni si e’ assistito ad incrementi rilevanti e disordinati dell’urbanizzazione nell’area vesuviana, per la maggior parte abusiva e con forti carenze strutturali, che, unitamente ad eventi piovosi particolarmente intensi nonché alle caratteristiche geologico-geomorfologiche del territorio, hanno causato eventi franosi parossistici come quelli dei comuni di Sarno, Episcopia e Bracigliano. L’area di indagine, rappresentata dal complesso vulcanico del Somma–Vesuvio in Campania, è densamente abitata (2500 abitanti per km2) ed oltre ad essere ad alto rischio vulcanico è anche esposta ad alto rischio idrogeologico come dimostrato dalle ripetute esondazioni disastrose fin dall’epoca storica (Accardo et al., 1981; Catenacci et al., 1992). La conoscenza dell’assetto geologico e geomorfologico del complesso Somma-Vesuvio è necessaria per una corretta individuazione dei parametri utili per questo studio. Un esempio è quello della caratterizzazione dei versanti del vulcano, fattore di notevole importanza per la valutazione del rischio idrogeologico, sia per la pendenza che per le loro caratteristiche morfologiche superficiali. Il primo parametro geomorfologico adottato per l’applicazione della metodologia (Tagil and Jenness, 2008) è stato l’indice di posizione topografica (TPI, Topographic Position Index) che ha consentito una classificazione del paesaggio sia in base alla distribuzione areale delle pendenze (slope position) che in classi uniformi di paesaggio (landform classes). La classificazione finale è stata adeguata al particolare paesaggio oggetto di studio, che è di tipo vulcanico. L’analisi della vulnerabilità è stata condotta tenendo conto della permeabilità del suolo e dei dati pluviometrici in quanto possibili fattori predisponenti al dissesto idrogeologico. Il GIS ha rappresentato lo strumento necessario per gestire dati di tipo diverso ed effettuarne l’analisi e la rappresentazione congiunta. Il software utilizzato è stato ArcGis (9.3) e attraverso l’applicazione Spatial Analyst è stato possibile estrarre dati ed informazioni nuove che non sarebbe stato possibile ottenere con l’analisi geomorfologica classica da cartografia su supporto cartaceo. La realizzazione di mappe di vulnerabilità idrogeologica dell’area del Somma-Vesuvio, ottenute stabilendo le relazioni tra i vari fattori incidenti con l’ausilio di metodologie note (Cherubini et al., 2006), ha rappresentato uno dei risultati del lavoro. Le interrelazioni tra i vari fattori (geologico, geomorfologico, idrogeologico, urbanistico) mostrate dalle mappe prodotte costituiscono uno strumento indispensabile per monitorare il rischio territoriale e per poter intervenire laddove venga superata una soglia di rischio ritenuta accettabile

Parameterization of a bucket model for soil-vegetation-atmosphere modeling under seasonal climatic regimes

We investigate the potential impact of accounting for seasonal variations in the climatic forcing and using different methods to parameterize the soil water content at field capacity on the water balance components computed by a bucket model (BM). The single-layer BM of Guswa et al. (2002) is employed, whereas the Richards equation (RE) based Soil Water Atmosphere Plant (SWAP) model is used as a benchmark model. The results are analyzed for two differently-textured soils and for some synthetic runs under real-like seasonal weather conditions, using stochastically-generated daily rainfall data for a period of 100 years. Since transient soil-moisture dynamics and climatic seasonality play a key role in certain zones of the World, such as in Mediterranean land areas, a specific feature of this study is to test the prediction capability of the bucket model under a condition where seasonal variations in rainfall are not in phase with the variations in plant transpiration. Reference is made to a hydrologic year in which we have a rainy period (starting 1 November and lasting 151 days) where vegetation is basically assumed in a dormant stage, followed by a drier and rainless period with a vegetation regrowth phase. Better agreement between BM and RE-SWAP intercomparison results are obtained when BM is parameterized by a field capacity value determined through the drainage method proposed by Romano and Santini (2002). Depending on the vegetation regrowth or dormant seasons, rainfall variability within a season results in transpiration regimes and soil moisture fluctuations with distinctive features. During the vegetation regrowth season, transpiration exerts a key control on soil water budget with respect to rainfall. During the dormant season of vegetation, the precipitation regime becomes an important climate forcing. Simulations also highlight the occurrence of bimodality in the probability distribution of soil moisture during the season when plants are dormant, reflecting that soil, it being of coarser or finer texture, can be preferentially in either wetter or drier states over this period

Kalman filters for assimilating near-surface observations into the Richards equation – Part 3: Retrieving states and parameters from laboratory evaporation experiments

Abstract. The purpose of this work is to evaluate the performance of a dual Kalman filter procedure in retrieving states and parameters of a one-dimensional soil water budget model based on the Richards equation, by assimilating near-surface soil water content values during evaporation experiments carried out under laboratory conditions. The experimental data set consists of simultaneously measured evaporation rates, soil water content and matric potential profiles. The parameters identified by assimilating the data measured at 1 and 2 cm soil depths are in very good agreement with those obtained by exploiting the observations carried out in the entire soil profiles. A reasonably good correspondence has been found between the parameter values obtained from the proposed assimilation technique and those identified by applying a non-sequential parameter estimation method. The dual Kalman filter also performs well in retrieving the water state in the porous system. Bias and accuracy of the predicted state profiles are affected by observation depth changes, particularly for the experiments involving low state vertical gradients. The assimilation procedure proved flexible and very stable in both experimental cases, independently from the selected initial conditions and the involved uncertainty

Kalman filters for assimilating near-surface observations into the Richards equation – Part 1: Retrieving state profiles with linear and nonlinear numerical schemes

Abstract. This paper examines the potential of different algorithms, based on the Kalman filtering approach, for assimilating near-surface observations into a one-dimensional Richards equation governing soil water flow in soil. Our specific objectives are: (i) to compare the efficiency of different Kalman filter algorithms in retrieving matric pressure head profiles when they are implemented with different numerical schemes of the Richards equation; (ii) to evaluate the performance of these algorithms when nonlinearities arise from the nonlinearity of the observation equation, i.e. when surface soil water content observations are assimilated to retrieve matric pressure head values. The study is based on a synthetic simulation of an evaporation process from a homogeneous soil column. Our first objective is achieved by implementing a Standard Kalman Filter (SKF) algorithm with both an explicit finite difference scheme (EX) and a Crank-Nicolson (CN) linear finite difference scheme of the Richards equation. The Unscented (UKF) and Ensemble Kalman Filters (EnKF) are applied to handle the nonlinearity of a backward Euler finite difference scheme. To accomplish the second objective, an analogous framework is applied, with the exception of replacing SKF with the Extended Kalman Filter (EKF) in combination with a CN numerical scheme, so as to handle the nonlinearity of the observation equation. While the EX scheme is computationally too inefficient to be implemented in an operational assimilation scheme, the retrieval algorithm implemented with a CN scheme is found to be computationally more feasible and accurate than those implemented with the backward Euler scheme, at least for the examined one-dimensional problem. The UKF appears to be as feasible as the EnKF when one has to handle nonlinear numerical schemes or additional nonlinearities arising from the observation equation, at least for systems of small dimensionality as the one examined in this study

Pathology of infantile cortical hyperostosis (Caffey's disease). Report of a case.

Late recurrence or a delayed form of Caffey's disease is an exceedingly rare condition of unknown cause. A 3 1/2-year-old boy is presented with delayed Caffey's disease showing unilateral involvement of maxilla and zygoma

Corrigendum to "Spatial moments of catchment rainfall: rainfall spatial organisation, basin morphology, and flood response" published in Hydrol. Earth Syst. Sci., 15, 3767–3783, 2011

No abstract available