[en] The multiperipheral ordered bootstrap of Rosenzweig and Veneziano is studied, using dual triple Regge couplings exhibiting the required threshold behavior. In the interval -.5 less than or equal to .8 GeV² self-consistent reggeon couplings and propagators are obtained for values of Regge slopes and intercepts consistent with the physical values for the leading natural-parity Regge trajectories. Cylinder effects are calculated on planar pole positions and couplings. By using an unsymmetrical planar π-rho reggeon loop model self-consistent solutions for the unnatural parity mesons can be obtained in the interval -.5 less than or equal to t less than or equal to .6 GeV². Neglecting effects of other Regge poles, the model gives a value of the π-eta splitting consistent with experiment

[en] The multiperipheral ordered bootstrap of Rosenzweig and Veneziano is studied by using dual triple Regge couplings exhibiting the required threshold behavior. In the interval -0.5 less than or equal to t less than or equal to 0.8 GeV² self-consistent reggeon couplings and propagators are obtained for values of Regge slopes and intercepts consistent with the physical values for the leading natural-parity Regge trajectories. Cylinder effects on planar pole positions and couplings are calculated. By use of an unsymmetrical planar π--rho reggeon loop model, self-consistent solutions are obtained for the unnatural-parity mesons in the interval -0.5 less than or equal to t less than or equal to 0.6 GeV². The effects of other Regge poles being neglected, the model gives a value of the π--eta splitting consistent with experiment. 24 figures, 1 table, 25 references

[en] In this work we study the pairing symmetry in a square lattice within a generalized Hubbard model, in which a second-neighbor correlated hopping is included in addition to the on-site and nearest-neighbor repulsions. When an infinitesimal distortion of the right angles in the square lattice is considered, we observe a spin triplet p-wave ground state for the case of electrons, but for holes a finite distortion is required, contrary to the d-wave case. In general, this spatial distortion induces a splitting of the doubly degenerate p-wave pairing states and one of them could become the ground state. On the other hand, this study has been extended to a finite density of electrons within the BCS formalism and the results show a maximum critical temperature of p-wave superconductivity around a 2/3 band-filling, close to the Fermi energy in the γ-band of Sr₂RuO₄ estimated by band-structure calculations

[en] Inverted relief of the Sierra de Segura area (province of Jaén, SE Spain) is characterized by the presence of numerous carbonate aquifers associated with topographic elevations of the Upper Cretaceous, which appear folded forming synclines. This geological structure controls the perched hydrogeological aquifer geometry, appearing in topographic highs and drained by numerous low discharge springs located in the geologic contact with the Albian sandy-marly impermeable sequence, called Utrillas Formation. Some of the most representative aquifers are Navalperal, Yelmo, Navalespino, Calar de Cobos or Bucentaina. To carry out the characterization of these springs, a monitoring network (60 groundwater samples and 7 rock samples) has been designed. Major, minor and trace elements were determined in water samples. X-ray diffraction (XRD) and scanning electron microscopy (SEM) analyses were carried out in the selected rocks for determining mineralogical and petrographical characterization. Major hydrochemical facies are calcium-magnesium bicarbonate and the predominant minerals are calcite, dolomite, potassium feldspar and quartz. Different hydrochemical diagrams show groups of springs based on altitude and the contents of marker ions would indicate hydrogeochemical evolution of the groundwater of the aquifers of the studied sector and their water-rock interaction. The chemical quality of these waters are according to the Spanish standard criteria established by the law, due to the scarce or no human pressure on the area and the nature of the aquifer materials. This sector could be considered an ideal location to define a prime location in a Mediterranean environment, where human influence on natural water resources is scarce.

[en] The effect of heating rate and annealing time on the microstructure and mechanical properties of a commercial 0.04% C Al-killed steel, cold rolled up to 80% is evaluated in the present study. For this purpose samples were isothermally annealed at various heating rates (12, 20, 40 and 650 degree centigree/min) and then soaked at 700 degree centigree for 15 h. The microstructural evolution of the samples during the heating process and holding temperature was evaluated by optical microscopy, scanning and transmission and transmission electron microscopy. Tensile mechanical properties and hardness measurements were also correlated with the microstructural features. Results showed that with soaking time greater than 6 h, the mechanical properties specified for the material are reached, even through, appropriate plastic anisotropy values were only obtained in samples heated at low rates, where a pancake type of structure is also formed. (Author) 38 refs

[en] A new electronic stopping power model for Monte Carlo simulation of ion implantation into 6H-SiC is presented. This model is based on the nonlinear density functional approach of Echenique et al. for the energy loss of slow ions moving through an electron gas and the ab initio pseudopotential calculations of Park et al. for the map of valence electrons of 6H-SiC crystal. A modified linear response theory has been used to treat the core electrons stopping. This model does not need fitting parameters and allows to fit the experimental distributions of implanted dopants in SiC both the peak region and the channeling tail of the SIMS profiles

[en] Presents the results of two of the tools implemented within this program, analyzing the strengths and possible areas for improvement identified in the behavior of the staff regarding the expectations of fixed safety culture, both for the revision of the program according to different parameters. The results obtained allow to raise the future lines of action of the programme and the initiatives to increase the culture of security personnel. (Author)

[en] We explain the sign difference between the natural-parity and the unnatural-parity cylinder by using a Reggeon-loop model proposed previously by Chew and Rosenzweig

[en] We present 9 cases of gas collection in the epidural space, revealed in CT scans of the spinal column. Five cases of herniated disc with accompanying vacuum, three of ''aerogen pseudocyst'' and a case of gas introduced iatrogenically via epidural installation catheter are included. (Author)

[en] To describe a case of leptomeningeal dissemination in a low-grade astrocytoma, a not common phenomenon in this kind of tumours, and to review the possibilities for its treatment. 8 month old boy in which a supratentorial low grade astrocytoma with widespread dissemination is observed. He is subjected to a treatment with systemic chemotherapy and controlled with MRI. After 17 months of therapy, an important reduction in tumour's size was observed, with scant toxicity and lack of secondary effects. Chemotherapy is a therapeutic choice to be considered in the future for the treatment of this kind of patients, in which surgery is not curative and radiotherapy is not advisable