Pairing Properties In Relativistic Mean Field Models Obtained From Effective Field Theory

We apply recently developed effective field theory nuclear models in mean field approximation (parameter sets G1 and G2) to describe ground-state properties of nuclei from the valley of $\beta$-stability up to the drip lines. For faster calculations of open-shell nuclei we employ a modified BCS approach which takes into account quasi-bound levels owing to their centrifugal barrier, with a constant pairing strength. We test this simple prescription by comparing with available Hartree-plus-Bogoliubov results. Using the new effective parameter sets we then compute separation energies, density distributions and spin--orbit potentials in isotopic (isotonic) chains of nuclei with magic neutron (proton) numbers. The new forces describe the experimental systematics similarly to conventional non-linear $\sigma-\omega$ relativistic force parameters like NL3.Comment: 29 pages, 17 figures, accepted for publication in PR

Pairing and continuum effects in nuclei close to the drip line

The Hartree-Fock-Bogoliubov (HFB) equations in coordinate representation are solved exactly, i.e., with correct asymptotic boundary conditions for the continuous spectrum. The calculations are preformed with effective Skyrme interactions. The exact HFB solutions are compared with HFB calculations based on box boundary conditions and with resonant continuum Hartree-Fock-BCS (HF-BCS) results. The comparison is done for the neutron-rich Ni isotopes. It is shown that close to the drip line the amount of pairing correlations depends on how the continuum coupling is treated. On the other hand, the resonant continuum HF-BCS results are generally close to those of HFB even in neutron-rich nuclei.Comment: 9 figures, corrected ref.

Surface Incompressibility from Semiclassical Relativistic Mean Field Calculations

By using the scaling method and the Thomas-Fermi and Extended Thomas-Fermi approaches to Relativistic Mean Field Theory the surface contribution to the leptodermous expansion of the finite nuclei incompressibility has been self-consistently computed. The validity of the simplest expansion, which contains volume, volume-symmetry, surface and Coulomb terms, is examined by comparing it with self-consistent results of the finite nuclei incompressibility for some currently used non-linear sigma-omega parameter sets. A numerical estimate of higher-order contributions to the leptodermous expansion, namely the curvature and surface-symmetry terms, is made.Comment: 18 pages, REVTeX, 3 eps figures, changed conten

Soft Dipole Modes in Neutron-rich Ni-isotopes in QRRPA

The soft dipole modes in neutron rich even-even Ni-isotopes are investigated in the quasiparticle relativistic random phase approximation. We study the evolution of strengths distribution, centroid energies of dipole excitation in low-lying and normal GDR regions with the increase of the neutron excess. It is found in the present study that the centroid energies of the soft dipole strengths strongly depend on the thickness of neutron skin along with the neutron rich even-even Ni-isotopes.Comment: 14 pages, 7 figure

Relativistic Mean Field Model with Generalized Derivative Nucleon-Meson Couplings

The quantum hadrodynamics (QHD) model with minimal nucleon-meson couplings is generalized by introducing couplings of mesons to derivatives of the nucleon field in the Lagrangian density. This approach allows an effective description of a state-dependent in-medium interaction in the mean-field approximation. Various parametrizations for the generalized couplings are developed and applied to infinite nuclear matter. In this approach, scalar and vector self-energies depend on both density and momentum similarly as in the Dirac-Brueckner theory. The Schr\"{o}diger-equivalent optical potential is much less repulsive at high nucleon energies as compared to standard relativistic mean field models and thus agrees better with experimental findings. The derivative couplings in the extended model have significant effects on properties of symmetric nuclear matter and neutron matter.Comment: 35 pages, 1 table, 10 figure

Plagas de almacén del arroz y enemigos naturales en Calasparra (Murcia)

Se ha realizado una prospección de las plagas y enemigos naturales presentes en los almacenes de arroz de la denominación de origen Calasparra durante 2001 y 2002. Con respecto a las plagas, se han identificado a: 9 especies de coleópteros, 3 de lepidópteros, 5 de psocópteros y 1 de acaridida. Las especies más dañinas encontradas fueron el capuchino de los granos (Rhizopertha dominica Fabricius) y el gorgojo del arroz (Sitophilus oryzae Linnaeus). Además, se capturaron diversos enemigos naturales como los parasitoides Anisopteromalus calandrae Howard y Lariophagus distinguendus Forster (Hymenoptera: Pteromalidae) y los depredadores Withius piger E. Simon (Pseudoscorpionoidea: Whitiidae) y Cheyletus malaccensis Oudemans (Acari: Cheyletidae). La presencia de plagas estuvo asociada a aquellos casos en donde tanto la temperatura como la humedad relativa presentaban valores por encima de lo recomendado para el almacenamiento del grano

Especies de la tribu Lamiini (Coleoptera, Cerambycidae) de la Reserva Biológica Alberto Manuel Brenes, San Ramón, Costa Rica

The knowledge of present species in protected areas has a great interest in order to estimate their biodiversity. In this work, we collected samples of the tribe Lamiini (Coleoptera: Cerambycidae) in the Reserva Biológica Alberto Manuel Brenes, San Ramón, Costa Rica. Eleven species of Lamiini were identif ied:Plagiohammus albatus, Plagiohammus elatus, Plagiohammus emanon, Plagiohammus rubefactus, Plagiohammus spinipennis, Deliathis nivea, Deliathis quadritaeniator, Neoptychodes cretatus, Ptychodes politus lecontei, Taeniotes praeclarus, Taeniotes scalatus and Taeniotes xanthostictus. Two of these (P. albatus and P. elatus) are new for the studied area. Figures, descriptions, collection dates and their abundance level are provided from each identified species.El conocimiento de las especies de insectos existentes en zonas protegidas es de enorme interés para cuantificar su biodiversidad. En este trabajo se presentan las once especies de la tribu Lamiini (Coleoptera: Cerambycidae) registradas en la Reserva Biológica Alberto Manuel Brenes (San Ramón, Costa Rica):Plagiohammus albatus, Plagiohammus elatus, Plagiohammus emanon, Plagiohammus rubefactus, Plagiohammus spinipennis, Deliathis nivea, Deliathis quadritaeniator, Neoptychodes cretatus, Ptychodes politus lecontei, Taeniotes praeclarus, Taeniotes scalatus y Taeniotes xanthostictus. Dos de ellas (P. albatus y P. elatus) son nuevas citas para la zona estudiada. De todas las especies identificadas se aportan figuras, datos descriptivos, registros de capturas y nivel de abundancia

Growth hormone insensitivity: Mexican case report

Herein, we present a 14-year-old patient with short stature (134 cm) referred from Paediatrics to our department for complementary evaluation since growth hormone (GH) treatment failed to show any improvement. He was born premature and small for gestational age. Genital examination classified the patient as Tanner I–II with small penis and testicular size for his age. Biochemical analyses revealed normal GH levels with low serum insulin-like growth factor-1 (IGF-1). Molecular diagnosis confirmed several mutations in IGF1R and IGFALS, and so he was diagnosed with Laron Syndrome or GH insensibility and treated with IGF-1 substitutive therapy

El complejo parasitario larvario de "helicoverpa armigera" Hübner sobre tomate en las Vegas del Guadiana (Extremadura)

La fauna de parasitoides larvarios de Helicoverpa armigera Hübner asociada a cultivos de tomate de industria se estudió en las Vegas del Guadiana durante el periodo 1995-1998. Se siguieron dos protocolos de muestreo: 1) muestreos puntuales en parcelas diseminadas por toda la zona de estudio y 2) muestreos sistemáticos cada 7-10 días en parcelas fijas enclavadas en La Orden, Guadajira (Badajoz) desde junio (floración-cuajado) hasta agosto-septiembre (recolección) e incluso octubre (recolección de tomate tardío). Las orugas recolectadas se individualizaron y criaron en laboratorio sobre medio semisintético hasta la finalización de su desarrollo, o muerte y emergencia de los parasitoides. El parasitismo larvario fue muy variable tanto entre campañas como a lo largo del ciclo de cultivo, alcanzándose en determinados muestreos valores totales de parasitismo bruto de casi el 70% y de parasitismo neto de hasta el 100%. El parasitoide más frecuente fue Cotesia kazak Telenga (Hym.: Braconidae) seguido de Hyposoter didymator Thunberg (Hym.: Ichneumonidae). La dinámica poblacional de ambos parasitoides difirió ostensiblemente: C. kazak se detectó a lo largo de todo el periodo muestreado, mientras que H. didymator no se manifestó desde aproximadamente mediados de julio hasta mediados de agosto. Aunque circunstancialmente se detectaron otras especies de himenópteros parasitoides, el complejo parasitario de C. kazak e H. didymator, supuso más del 95% del parasitismo larvario total en H. armigera sobre tomate en las Vegas del Guadiana. Para finalizar, se discuten diversos aspectos relacionados con la fiabilidad de los muestreos, con la concurrencia ecológica de C. kazak e H. didymator así como con la trascendencia de este complejo parasitario y su aconsejable potenciación en los programas de control integrado en tomate de industria que se ejecutan actualmente en las Vegas del Guadiana