[en] It is shown that the dual of the double compactified D=11 Supermembrane and a suitable compactified D=10 Super 4D-brane with nontrivial wrapping on the target space may be formulated as non-commutative gauge theories. The Poisson bracket over the world-volume is intrinsically defined in terms of the minima of the hamiltonian of the theory, which may be expressed in terms of a non degenerate 2-form. A deformation of the Poisson bracket in terms of the Moyal brackets is then performed. A non-commutative gauge theory in terms of the Moyal star bracket is obtained. It is shown that all these theories may be described in terms of symplectic connections on symplectic fibrations, the world volume being its base manifold and the (sub)group of volume preserving diffeomorphisms, p = 2 (p > 2), generate the symplectomorphisms which preserve the (infinite dimensional) Poisson bracket of the fibration

[en] It is shown that a double compactified D=11 supermembrane with nontrivial wrapping may be formulated as a symplectic noncommutative gauge theory on the world volume. The symplectic noncommutative structure is intrinsically obtained from the symplectic two-form on the world volume defined by the minimal configuration of its Hamiltonian. The gauge transformations on the symplectic fibration are generated by the area preserving diffeomorphisms on the world volume. Geometrically, this gauge theory corresponds to a symplectic fibration over a compact Riemann surface with a symplectic connection

[en] Reservoir storage has been the predominant strategy to address hydrologic variability in water scarce regions. The reliability of water supply can be significantly enhanced if enough water is stored in reservoirs to overcome supply deficit during low flow periods. Many reservoir sizing techniques have been developed to define the minimum reservoir capacity required to supply a given demand at a certain location with enough reliability (Vogel 1987; Vogel et al. 2007). These techniques usually normalize reservoir storage and yield dividing by mean annual flow to account for local conditions. For a given required reliability, the relationship between storage and yield depends on hydrologic variability, which is usually accounted through the coefficient of variation of annual flows. The resulting relations are usually known as StorageYield-Reliability (S-Y-R) curves. Anticipated changes in the mean and coefficient of variation of annual flows due to climate change will affect reservoir performance. The impacts may be estimated through the analysis of S-Y-R relations. In this work we analyse the observed and projected performance of storage reservoirs in Europe. The objective is to explore the validity of the S-Y-R approach to predict climate change impacts on regulated water supply systems.

[en] A model-independent search for deviations from the Standard Model prediction has been performed in e⁺p and e^-p collisions at HERA using H1 data. All experimentally measurable event topologies involving isolated electrons, photons, muons, neutrinos and jets with high transverse momenta have been investigated. A good agreement with the Standard Model prediction is found in most of the event classes. A new algorithm has been developed to look for regions with large deviations from the Standard Model in the invariant mass and sum of transverse momenta distributions and to quantify the significance of the fluctuations observed. The largest deviation is found in topologies with an isolated muon, missing transverse momentum and a jet which confirms previous observations. About 2% of hypothetical Monte Carlo experiments would produce deviations more significant than the one observed in the corresponding distribution of sum of transverse momenta. (orig.)

[en] In order to estimate extreme flood hydrographs accurately by stochastic approaches, it is necessary to carry on hydrologic simulations of thousands of years. By using continuous fully distributed simulation models we are able to derive flood frequency distributions from the continuous hourly streamflow obtained at any desired point in the drainage network of the basin. This approach has the advantage of estimating the variables for the entire period of simulation. However, continuous models tend to be more complex than event-based models, with computational efforts that could be very intensive, even by using high performance computing and parallelization processes. Event-based simulations require much shorter simulation times. Among other disadvantages, the maximum annual rainfall does not necessarily have to produce the maximum annual flood. Furthermore, different properties of storm events could affect in the derivation of flood frequency curves: rainfall temporal distribution, event duration, maximum intensity, total storm depth, etc. Therefore, the estimation of high return period flood frequency curves by using event-based models is a challenge. This paper focuses on addressing this challenge by analysing the results obtained by coupling a continuous stochastic weather generator with a continuous distributed physically-based hydrological model. The objective is to propose a criterion for the selection of the minimum number of storm events per year to guarantee a correct derivation of the flood frequency curve for high return periods, according to its maximum annual peak-flow, maximum annual volume, and the bivariate analysis of both variables. The outcomes of this research would be useful for event-based model applications.

[en] The diffuse spectral series, 2S²np ²P-2s² nd²D, of the boron isoelectronic sequence has been studied through a one-particle scheme, by explicitly treating only the active electron. Oscillator strengths for various transitions (n = 2,3; n' = 3-16) have been computed with the quantum defect and relativistic quantum defect formalisms, and results comparing very satisfactory with other theoretical data have been obtained

[en] A summary of the relativistic quantum defect orbital (RQDO) method, as well as a few numerical examples of oscillator strengths, are presented. The radial functions in this formalism derive from solving a form of the decoupled second-order Dirac radial equation. With the method being totally analytical, it constitutes a simple and reliable procedure for predicting properties of interest in astrophysics and fusion plasma research, such as transition probabilities, while accounting for a large part of relativistic effects. Core polarization during electron transitions can also be explicitly accounted for in an analytic form

[en] The nanocrystalline microstructure evolution of Zr_41.2Ti_13.8Cu_12.5Ni_10.0Be_22.5 metallic glass has been studied by three-dimensional atom probe (3DAP), transmission electron microscopy (TEM), and small-angle X-ray scattering (SAXS). Nanoscale icosahedral phase (i-phase) precipitates from a single amorphous phase by isothermally annealing at slightly above the glass transition temperature, T_g, followed by the formation of Be₂Zr and CuZr₂ phases. A uniform featureless amorphous-like contrast was observed by TEM before the i-phase nanoparticles were detected. 3DAP analysis results have convincingly shown that the decomposition occurs only when i-phase nanoparticles were observed by TEM. The Ti-rich and Be-depleted region that appears in the early stage annealing is due to the partitioning of the alloying elements accompanied by the crystallization reaction. No evidence for prior decomposition in the amorphous state was obtained

[en] AIMS: To review the imaging features of mucinous cystic neoplasms (MCNs) of the pancreas and to highlight difficulties in differentiating these lesions from pancreatic pseudocysts. MATERIALS AND METHODS: The imaging investigations, case notes and histopathology of 13 patients who underwent surgery for an MCN of the pancreas, were reviewed. RESULTS: An erroneous diagnosis of a pancreatic pseudocyst had been made in five of the 13 cases and in two patients cystenterostomy had been performed. Only one patient had a documented history of acute pancreatitis although mildly elevated serum amylase levels were identified in a further five cases. CT and US correctly diagnosed a cystic pancreatic mass in all 13 patients, however cross-sectional imaging features of neoplasia, such as septae, cyst wall calcification, focal thickening of the cyst wall and papillary projections, were absent in five (38%) cases. Coexistent imaging features of chronic pancreatitis were present in five of the 13 patients and in six resected specimens. Cyst wall calcification occurred only in malignant lesions and there was no relationship between cyst size and the degree of malignancy. While ERCP, angiography, and percutaneous needle aspiration may provide additional information, the majority of these examinations were either unhelpful or even misleading. CONCLUSION: MCNs of the pancreas are frequently diagnosed and mismanaged as pancreatic pseudocysts with an associated increase in patient morbidity and mortality. Diagnostic imaging can help to distinguish MCNs from pseudocysts when there are features of neoplasia present, however, no imaging investigation can reliably differentiate the two conditions in all cases. If clinical doubt remains, it is preferable to err on the side of safety and either employ a 'wait and watch' strategy or to resect a cystic pancreatic lesion rather than drain a potentially malignant MCN. Scott, J. (2000)

[en] In the mining-metallurgical companies different liquid effluents are produced, which can contain a series of dissolved elements that are considered dangerous from an environmental point of view. One of these elements is the arsenic, especially in the state of oxidation +5 that can be precipitated as calcium or iron arsenate. To fulfil the environmental requests it should have in solution a content of arsenic lower than 0,5 mg/l and the obtained solid product should be very stable under the condition in which it will be stored. this work looks for the best conditions of arsenic precipitation, until achieving contents in solution lower than such mentioned concentration. Also, the stability of the precipitates was studied. (Author) 7 refs