The Iberian Massif of western Asturias and Lugo: a record of landscape forming processes during 107 time-scales.

El relieve transitorio del occidente Asturiano y Lugo, desarrollado sobre rocas del Macizo Ibérico, contiene información sobre los procesos pasados y recientes que condicionan la topográfica. Un análisis geomorfológico, basado en el uso de Sistemas de Información Geográfica, combinado con técnicas de termocronología de baja temperatura y de análisis de isótopos cosmogénicos, ha permitido identificar varios componentes del paisaje con edades y significados geodinámicos diferentes. Estos son: 1) paleosuperficies de bajo relieve con bajas tasas de denudación, interpretadas como relictos de un periodo entre los 100 y 45 Ma en que se desarrollaron relieves maduros; 2) pequeños ríos costeros que presentan tasas de denudación moderadas asociadas a una lenta elevación del terreno durante el Neógeno; 3) una ancha superficie de abrasión submarina, elevada lentamente (0.07-0.15 mm/a) sobre el nivel del mar desde hace 1.5 Ma. Las rocas de esta región registran tasas de exhumación más altas antes del Cretácico Superior, durante la extensión Mesozoica en el Atlántico y Golfo de Vizcaya. Las tasas de exhumación se redujeron durante el periodo de relativa estabilidad tectónica iniciado después de la ruptura continental en el Cretácico Inferior. El sistema de denudación ha permanecido poco eficiente durante la elevación topográfica iniciada en el Eoceno.Estos estudios han sido financiados a través de los proyectos BTE2002-00330, CGL2005-24204 y CGL2007-60230/BTE de los Ministerios de Educación y Ciencia y de Ciencia e Innovación. Se incluyen en el marco del proyecto “TOPO-Iberia”, Consolider-Ingenio 2010, CSD2006-00041.Peer Reviewe

On inconsistency of experimental data on primary nuclei spectra with sea level muon intensity measurements

For the first time a complete set of the most recent direct data on primary cosmic ray spectra is used as input into calculations of muon flux at sea level in wide energy range $E_\mu=1-3\cdot10^5$ GeV. Computations have been performed with the CORSIKA/QGSJET and CORSIKA/VENUS codes. The comparison of the obtained muon intensity with the data of muon experiments shows, that measurements of primary nuclei spectra conform to sea level muon data only up to several tens of GeV and result in essential deficit of muons at higher energies. As it follows from our examination, uncertainties in muon flux measurements and in the description of nuclear cascades development are not suitable to explain this contradiction, and the only remaining factor, leading to this situation, is underestimation of primary light nuclei fluxes. We have considered systematic effects, that may distort the results of the primary cosmic ray measurements with the application of the emulsion chambers. We suggest, that re-examination of these measurements is required with the employment of different hadronic interaction models. Also, in our point of view, it is necessary to perform estimates of possible influence of the fact, that sizable fraction of events, identified as protons, actually are antiprotons. Study of these cosmic ray component begins to attract much attention, but today nothing definite is known for the energies $>40$ GeV. In any case, to realize whether the mentioned, or some other reasons are the sources of disagreement of the data on primaries with the data on muons, the indicated effects should be thoroughly analyzed

Shell structure of superheavy nuclei in self-consistent mean-field models

We study the extrapolation of nuclear shell structure to the region of superheavy nuclei in self-consistent mean-field models -- the Skyrme-Hartree-Fock approach and the relativistic mean-field model -- using a large number of parameterizations. Results obtained with the Folded-Yukawa potential are shown for comparison. We focus on differences in the isospin dependence of the spin-orbit interaction and the effective mass between the models and their influence on single-particle spectra. While all relativistic models give a reasonable description of spin-orbit splittings, all non-relativistic models show a wrong trend with mass number. The spin-orbit splitting of heavy nuclei might be overestimated by 40%-80%. Spherical doubly-magic superheavy nuclei are found at (Z=114,N=184), (Z=120,N=172) or (Z=126,N=184) depending on the parameterization. The Z=114 proton shell closure, which is related to a large spin-orbit splitting of proton 2f states, is predicted only by forces which by far overestimate the proton spin-orbit splitting in Pb208. The Z=120 and N=172 shell closures predicted by the relativistic models and some Skyrme interactions are found to be related to a central depression of the nuclear density distribution. This effect cannot appear in macroscopic-microscopic models which have a limited freedom for the density distribution only. In summary, our findings give a strong argument for (Z=120,N=172) to be the next spherical doubly-magic superheavy nucleus.Comment: 22 pages REVTeX, 16 eps figures, accepted for publication in Phys. Rev.