Three Flavour Majorana Neutrinos with Magnetic Moments in a Supernova

The resonant transition effects MSW and NSFP for three flavour Majorana neutrinos in a supernova are considered, where the transition magnetic moments are likely to play a relevant role in neutrino physics. In this scenario, the deformed thermal neutrino distributions are obtained for different choices of the electron-tau mixing angle. Detailed predictions for the future large neutrino detectors are also given in terms of the ratio between the spectra of recoil electrons for deformed and undeformed spectra.Comment: 20 pages, LaTeX, 5 figures.p

Climatic control on the variability of flood distribution

International audienceThe variability of the second order moments of flood peaks with respect to geomorphoclimatic basin characteristics was investigated. In particular, the behaviour of the coefficient of variation (Cv) of the series of annual maximum floods was analysed with respect to its dependence on physically consistent quantities. The results achieved were in fairly good agreement with real world observed characteristics and interesting insights on the relationship between Cv and basin size were found. It appears that Cv is controlled mainly by the climate and by some water loss features. Many observations reported in the literature show a decrease of Cv with basin area A, usually ascribed to the limited spatial extent of extreme events, which leads to a decrease with area of the Cv of areal rainfall intensity. An increase of Cv with the area is also sometimes observed for small basins. Such different behaviours were accounted for by the concurrent effect on two parameters that affect the Cv (A) relationship, representative of the way rainfall losses and effective rainfall intensity scale with the basin area.</p

Flood quantiles estimation based on theoretically derived distributions: regional analysis in Southern Italy

A regional probabilistic model for the estimation of medium-high return period flood quantiles is presented. The model is based on the use of theoretically derived probability distributions of annual maximum flood peaks (DDF). The general model is called TCIF (Two-Component IF model) and encompasses two different threshold mechanisms associated with ordinary and extraordinary events, respectively. Based on at-site calibration of this model for 33 gauged sites in Southern Italy, a regional analysis is performed obtaining satisfactory results for the estimation of flood quantiles for return periods of technical interest, thus suggesting the use of the proposed methodology for the application to ungauged basins. The model is validated by using a jack-knife cross-validation technique taking all river basins into consideration

Regional analysis of runoff thresholds behaviour in Southern Italy based on theoretically derived distributions

The analysis of runoff thresholds and, more in general, the identification of main mechanisms of runoff generation controlling the flood frequency distribution is investigated, by means of theoretically derived flood frequency distributions, in the framework of regional analysis. Two nested theoretically-derived distributions are fitted to annual maximum flood series recorded in several basins of Southern Italy. Results are exploited in order to investigate heterogeneities and homogeneities and to obtain useful information for improving the available methods for regional analysis of flood frequency

Effects of runoff thresholds on flood frequency distributions

International audienceRunoff generation during extreme floods usually occurs whenever rainfall forcing exceeds a given threshold. In many cases, different thresholds may be identified as responsible of the hydrological losses during ordinary events or extraordinary events at the basin scale. Such thresholds are shown to be related to the dynamics of soil saturation of the river basin and to account for the high skewness of their annual flood distributions. In basins where ordinary floods are mostly due to a small portion of the surface which is particularly prone to produce runoff, depending on permeability of a river basin and its antecedent soil moisture conditions, severe rainfall may exceed a basin-wide soil storage threshold and produce the so-called outlier events responsible of the high skewness of floods distributions. In this context, the derived theoretical model based on the concept of variable contributing area to peak flow proposed by Iacobellis and Fiorentino (2000) was generalized with the aim of incorporating such kind of dynamics in the description of the phenomena. The work produced a new formulation of the derived distribution where the two runoff components are explicitly considered. The present work was validated by using as test site a group of basins belonging to Southern Italy and characterized by flood distributions with high skewness. The application of the proposed model provided a good fitting to the observed distributions. Moreover, model parameters were found to be strongly related to physiographic basin characteristics giving consistency to the modelling assumptions

Analysis on flood generation processes by means of a continuous simulation model

International audienceIn the present research, we exploited a continuous hydrological simulation to investigate on key variables responsible of flood peak formation. With this purpose, a distributed hydrological model (DREAM) is used in cascade with a rainfall generator (IRP-Iterated Random Pulse) to simulate a large number of extreme events providing insight into the main controls of flood generation mechanisms. Investigated variables are those used in theoretically derived probability distribution of floods based on the concept of partial contributing area (e.g. Iacobellis and Fiorentino, 2000). The continuous simulation model is used to investigate on the hydrological losses occurring during extreme events, the variability of the source area contributing to the flood peak and its lag-time. Results suggest interesting simplification for the theoretical probability distribution of floods according to the different climatic and geomorfologic environments. The study is applied to two basins located in Southern Italy with different climatic characteristics

CHARACTERIZATION OF THE FUNCTIONAL ROLE OF NEW VARIANTS INVOLVED IN VARIEGATE PORPHYRIA AND HIPSC DERIVED HEPATOCYTE LIKE CELLS TO MODEL HEPATIC PORPHYRIAS

Porphyrias are a group of inherited metabolic disorders of heme biosynthesis. Each porphyria derives from an alteration in the heme biosynthetic pathway resulting in a specific accumulation of heme precursors. These rare diseases are characterized by an extended heterogeneity of mutations affecting the coding region of the genes directly or indirectly involved in the pathway. In this study, we assessed three new variants identified in the regulatory regions of the PPOX gene using human hepatocarcinoma (Hep3B) and erythroleukemia (K562) cell lines. We demonstrated a lower expression of the PPOX gene through luciferase assays and RNA analysis for the c.1-883G>C promoter mutant and we suggested a post-transcriptional role for the c.1-413G>T and c.1-176G>A variants in the 5\u2032 UTR of PPOX mRNA variant 2. Transfection experiments of mutant -413T reporter plasmid indicate that this variant inhibits translation of the downstream firefly luciferase mRNA. In fact, the reduced firefly luciferase activity did not correlate with the proportional reduction in firefly luciferase mRNA expression. Normal values of PPOX mRNA level validated with Digital PCR in the patient carrying the c.1-413G>T substitution support this evidence. Data for the c.1-176G>A variant show a possible role in the spicing regulation for it. The qualitative RNA analysis confirms that this variant is involved in the alteration of the normal splicing between exon 1 and exon 2 of PPOX due to a 4 bp deletions in exon 1. The relation between these post-transcriptional alterations and the variegate porphyria remains to be investigated. These results suggest that the regulatory regions have to be considered in the diagnostic process but more studies are required to clarify their role in the disease. To model hepatic porphyrias, we derived hepatocyte-like cells from hiPSC generated from blood of two patients affected by acute intermittent porphyria, a hepatic porphyria. We hypothesized that this can serve as an in vitro model to study different pathways linked with acute intermittent porphyria. The data suggest a general comparable profile of the heme biosynthec pathway between hiPSC-HLC and primary hepatocytes. Although some immature features, probably linked with the in vitro condition, could directly or indirectly affect the metabolism network links with hepatic porphyrias, now hiPSC-HLCs are one of the most useful model available for hepatic diseases. The patient derived hepatocyte-like cells showed a basal overexpression of ALAS1 and its regulator PPARA and PGC1A with induction of oxidative damage response genes. Moreover, the induction of ketogenetic and lipid metabolic genes highlighted a different metabolic profile in the acute intermittent porphyria patient lines. The in vitro simulation of acute attack mediated by ALA administration, one of the principal compound accumulated during the attack, showed a negative feedback regulation on ALAS1 with massive induction of HMOX1 in the control cell line. On the other hand, phenobarbital response in control line suggested the link between cholesterol synthesis and gluconeogenesis with the heme biosynthetic pathway. The drug metabolism in fact, induces the heme biosynthetic pathway through ALAS1, and this gene results constantly overexpressed in the derived patient cell lines. In conclusion, this study focus the attention on the importance of the regulatory regions in the diagnostic process of porphyrias and supply an alternative in vitro model to study the metabolic alterations linked with porphyrias. Further experiments are required to better understand the direct effect of alteration in the regulatory regions of porphyria genes and are necessary to analyse the involvement of different pathways in the onset of the disease

Strong low-frequency quantum correlations from a four-wave mixing amplifier

We show that a simple scheme based on nondegenerate four-wave mixing in a hot atomic vapor behaves like a near-perfect phase-insensitive optical amplifier, which can generate bright twin beams with a measured quantum noise reduction in the intensity difference of more than 8 dB, close to the best optical parametric amplifiers and oscillators. The absence of a cavity makes the system immune to external perturbations, and the strong quantum noise reduction is observed over a large frequency range.Comment: 4 pages, 4 figures. Major rewrite of the previous version. New experimental results and further analysi

Best Fit and Selection of Theoretical Flood Frequency Distributions Based on Different Runoff Generation Mechanisms

Theoretically derived distributions allow the detection of dominant runoff generation mechanisms as key signatures of hydrologic similarity. We used two theoretically derived distributions of flood peak annual maxima: the first is the ―IF‖ distribution, which exploits the variable source area concept, coupled with a runoff threshold having scaling properties; the second is the Two Component-IF (TCIF) distribution, which generalizes the IF distribution, and is based on two different threshold mechanisms, associated with ordinary and extraordinary events, respectively. By focusing on the application of both models to two river basins, of sub-humid and semi-arid climate in Southern Italy, we present an ad hoc procedure for the estimation of parameters and we discuss the use of appropriate techniques for model selection, in the case of nested distributions