Nuclear pairing: surface or bulk?

We analyze how the spatial localization properties of pairing correlations are changing in a major neutron shell of heavy nuclei. It is shown that the radial distribution of the pairing density depends strongly on whether the chemical potential is close to a low or a high angular momentum level and has little sensitivity to whether the pairing force acts at the surface or in the bulk. The pairing density averaged over one major shell is, however, rather flat, exhibiting little dependence on the pairing force. Hartree-Fock-Bogoliubov calculations for the isotopic chain 100-132Sn are presented for demonstration purposes.

Sum rules and correlations in asymmetric nuclear matter

The neutron and proton single-particle spectral functions in asymmetric nuclear matter fulfill energy-weighted sum rules. The validity of these sum rules within the self-consistent Green's function approach is investigated. The various contributions to these sum rules and their convergence as a function of energy provide information about correlations induced by the realistic interaction between the nucleons. The study of the sum rules in asymmetric nuclear matter exhibits the isospin dependence of the nucleon-nucleon correlations.

Theoretical study of the structural dependence of nuclear quadrupole frequencies in high-T_c superconductors

The remarkable difference between the nuclear quadrupole frequencies v_Q of Cu(1) and Cu(2) in YBa_2Cu_3O_6 and YBa_2Cu_3O_7 is analyzed. We calculate the ionic contribution to the electric field gradients and estimate, by using experimental results for Cu_2O and La_2CuO_4, the contribution of the d valence electrons. Thus, we determine v_Q1, v_Q2, and the asymmetry parameter η for YBa_2Cu_3O_6 and YBa_2Cu_3O_7. The number of holes in dthe Cu-O planes and chains is found to be important for the different behavior of v_Q1 and v_Q2.

Nuclear charge radii from X-ray transitions in muonic atoms of carbon, nitrogen and oxygen

Energies of muonic X-rays of the K-series of carbon, nitrogen and oxygen have been measured with an accuracy of about 15 eV. Root mean square radii of the nuclear charge distributions were deduced. The results 2.49±0.05 fm for carbon, 2.55 ±0.03 fm for nitrogen and 2.71 ±0.02 fm for oxygen are in good agreement at comparable accuracy with recent electron scattering data.

Elastic nuclear scattering at intermediate and relativistic energies

The classical scattering cross section of two colliding nuclei at intermediate and relativistic energies is reevaluated. The influence of retardation and magnetic field effects is taken into account. Corrections due to electron screening as well as due to attractive nuclear forces are discussed. This paper represents an addendum to [l].

Effect of nuclear motion on the energy eigenvalues in muonic atoms

I have investigated the effect of the nuclear motion on the energy eigenvalues in muonic atoms. In addition to the usually used reduced-mass correction, I have calculated the relativistic influences including the magnetic and retardation interaction between the nucleus and the muon for the inner orbitals of muonic atoms.

Nuclear organisation and epigenetic regulation of gene expression in Dictyostelium discoideum

A series of vectors for the over-expression of tagged proteins in Dictyostelium were designed, constructed and tested. These vectors allow the addition of an N- or C-terminal tag (GFP, RFP, 3xFLAG, 3xHA, 6xMYC and TAP) with an optimized polylinker sequence and no additional amino acid residues at the N or C terminus. Different selectable markers (Blasticidin and gentamicin) are available as well as an extra chromosomal version; these allow copy number and thus expression level to be controlled, as well as allowing for more options with regard to complementation, co- and super-transformation. Finally, the vectors share standardized cloning sites, allowing a gene of interest to be easily transfered between the different versions of the vectors as experimental requirements evolve. The organisation and dynamics of the Dictyostelium nucleus during the cell cycle was investigated. The centromeric histone H3 (CenH3) variant serves to target the kinetochore to the centromeres and thus ensures correct chromosome segregation during mitosis and meiosis. A number of Dictyostelium histone H3-domain containing proteins as GFP-tagged fusions were expressed and it was found that one of them functions as CenH3 in this species. Like CenH3 from some other species, Dictyostelium CenH3 has an extended N-terminal domain with no similarity to any other known proteins. The targeting domain, comprising α-helix 2 and loop 1 of the histone fold is required for targeting CenH3 to centromeres. Compared to the targeting domain of other known and putative CenH3 species, Dictyostelium CenH3 has a shorter loop 1 region. The localisation of a variety of histone modifications and histone modifying enzymes was examined. Using fluorescence in situ hybridisation (FISH) and CenH3 chromatin-immunoprecipitation (ChIP) it was shown that the six telocentric centromeres contain all of the DIRS-1 and most of the DDT-A and skipper transposons. During interphase the centromeres remain attached to the centrosome resulting in a single CenH3 cluster which also contains the putative histone H3K9 methyltransferase SuvA, H3K9me3 and HP1 (heterochromatin protein 1). Except for the centromere cluster and a number of small foci at the nuclear periphery opposite the centromeres, the rest of the nucleus is largely devoid of transposons and heterochromatin associated histone modifications. At least some of the small foci correspond to the distal telomeres, suggesting that the chromosomes are organised in a Rabl-like manner. It was found that in contrast to metazoans, loading of CenH3 onto Dictyostelium centromeres occurs in late G2 phase. Transformation of Dictyostelium with vectors carrying the G418 resistance cassette typically results in the vector integrating into the genome in one or a few tandem arrays of approximately a hundred copies. In contrast, plasmids containing a Blasticidin resistance cassette integrate as single or a few copies. The behaviour of transgenes in the nucleus was examined by FISH, and it was found that low copy transgenes show apparently random distribution within the nucleus, while transgenes with more than approximately 10 copies cluster at or immediately adjacent to the centromeres in interphase cells regardless of the actual integration site along the chromosome. During mitosis the transgenes show centromere-like behaviour, and ChIP experiments show that transgenes contain the heterochromatin marker H3K9me2 and the centromeric histone variant H3v1. This clustering, and centromere-like behaviour was not observed on extrachromosomal transgenes, nor on a line where the transgene had integrated into the extrachromosomal rDNA palindrome. This suggests that it is the repetitive nature of the transgenes that causes the centromere-like behaviour. A Dictyostelium homolog of DET1, a protein largely restricted to multicellular eukaryotes where it has a role in developmental regulation was identified. As in other species Dictyostelium DET1 is nuclear localised. In ChIP experiments DET1 was found to bind the promoters of a number of developmentally regulated loci. In contrast to other species where it is an essential protein, loss of DET1 is not lethal in Dictyostelium, although viability is greatly reduced. Loss of DET1 results in delayed and abnormal development with enlarged aggregation territories. Mutant slugs displayed apparent cell type patterning with a bias towards pre-stalk cell types.

Electron-Nuclear Correlation in Laser-Driven Diatomic Molecules

The interaction of short intense laser pulses with atoms/molecules produces a multitude of highly nonlinear processes requiring a non-perturbative treatment. Detailed study of these highly nonlinear processes by numerically solving the time-dependent Schrodinger equation becomes a daunting task when the number of degrees of freedom is large. Also the coupling between the electronic and nuclear degrees of freedom further aggravates the computational problems. In the present work we show that the time-dependent Hartree (TDH) approximation, which neglects the correlation effects, gives unreliable description of the system dynamics both in the absence and presence of an external field. A theoretical framework is required that treats the electrons and nuclei on equal footing and fully quantum mechanically. To address this issue we discuss two approaches, namely the multicomponent density functional theory (MCDFT) and the multiconfiguration time-dependent Hartree (MCTDH) method, that go beyond the TDH approximation and describe the correlated electron-nuclear dynamics accurately. In the MCDFT framework, where the time-dependent electronic and nuclear densities are the basic variables, we discuss an algorithm to calculate the exact Kohn-Sham (KS) potentials for small model systems. By simulating the photodissociation process in a model hydrogen molecular ion, we show that the exact KS potentials contain all the many-body effects and give an insight into the system dynamics. In the MCTDH approach, the wave function is expanded as a sum of products of single-particle functions (SPFs). The MCTDH method is able to describe the electron-nuclear correlation effects as the SPFs and the expansion coefficients evolve in time and give an accurate description of the system dynamics. We show that the MCTDH method is suitable to study a variety of processes such as the fragmentation of molecules, high-order harmonic generation, the two-center interference effect, and the lochfrass effect. We discuss these phenomena in a model hydrogen molecular ion and a model hydrogen molecule. Inclusion of absorbing boundaries in the mean-field approximation and its consequences are discussed using the model hydrogen molecular ion. To this end, two types of calculations are considered: (i) a variational approach with a complex absorbing potential included in the full many-particle Hamiltonian and (ii) an approach in the spirit of time-dependent density functional theory (TDDFT), including complex absorbing potentials in the single-particle equations. It is elucidated that for small grids the TDDFT approach is superior to the variational approach.

Escuela y cooperación : iniciación al asociacionismo en la EGB.

La Consejería de Agricultura en Murcia, estableció durante el curso 83/84 un plan de iniciación al asociacionismo en colaboración con el Ministerio de Educación en algunos centros de EGB. Este documento trata de proporcionar un instrumento útil a profesores y alumnos, principales destinatarios de este trabajo, para fomentar hábitos tendentes al asociacionismo, muy útiles en la actividad agraria. Se realiza un análisis del asociacionismo agrario y causas del trabajo, planteando la necesidad de elaborar un programa educativo que incida en los aspectos formativos, de actitudes hacia la cooperación. Establece una serie de objetivos entre los que cabe señalar los siguientes: que el alumno descubra, entre los problemas del medio, aquellos que precisen para su solución la vía asociativa; que conozca el nacimiento, evolución y filosofía del cooperativismo y analice la estructura socio-económica de la cooperativa de su localidad.

Los jóvenes y la cooperación solidaria : exposición itinerante.

El recurso es el catálogo de una exposición itinerante que recoge los 13 paneles de que constaba la misma, además de un expositor computerizado. La exposición trata de dar contenidos a la educación para la cooperación al desarrollo. Los paneles tratan los siguientes temas: un único mundo dividido; un único mundo solidario; el desarrollo humano; el desarrollo: sus consecuencias; una Europa solidaria; el papel de las organizaciones no gubernamentales (ONGs); experiencias de proyectos de cooperación al desarrollo internacional; el papel del voluntariado en la cooperación al desarrollo; la educación para el desarrollo humano(II); el derecho al desarrollo; del presente al futuro del desarrollo humano.

Del yo al euro : una propuesta didáctica de cooperación transnacional : educación permanente de adultos. 'From the I to the euro : a didactic proposal for transnational cooperation : permanent adult education'.

La obra se presenta en edición bilingue español/inglés .- Incluye una sección de apéndices en la que aparecen tablas y gráficos que recogen datos estadísticos sobre la experiencia didáctica, así como información general sobre la UE

Advanced Nuclear Energy Systems: Heat Transfer Issues and Trends

Almost 450 nuclear power plants are currently operating throughout the world and supplying about 17% of the world’s electricity. These plants perform safely, reliably, and have no free-release of byproducts to the environment. Given the current rate of growth in electricity demand and the ever growing concerns for the environment, the US consumer will favor energy sources that can satisfy the need for electricity and other energy-intensive products (1) on a sustainable basis with minimal environmental impact, (2) with enhanced reliability and safety and (3) competitive economics. Given that advances are made to fully apply the potential benefits of nuclear energy systems, the next generation of nuclear systems can provide a vital part of a long-term, diversified energy supply. The Department of Energy has begun research on such a new generation of nuclear energy systems that can be made available to the market by 2030 or earlier, and that can offer significant advances toward these challenging goals [1]. These future nuclear power systems will require advances in materials, reactor physics as well as heat transfer to realize their full potential. In this paper, a summary of these advanced nuclear power systems is presented along with a short synopsis of the important heat transfer issues. Given the nature of research and the dynamics of these conceptual designs, key aspects of the physics will be provided, with details left for the presentation.

Actitudes de cooperación en los niños que asisten al ciclo medio de escuelas-hogar.

Comprobar que las actitudes de cooperación que presentan los alumnos de escuela-hogar responden a lo observado. 382 alumnos y 34 profesores del ciclo medio de EGB. Análisis de la actual situación de las escuelas-hogar: régimen jurídico, admisión de alumnos, etc. Elaboración del cuestionario para los alumnos y profesores. Pasación de cuestionarios. Análisis de datos. Cuestionarios para profesores y alumnos. Técnicas de análisis estadístico, media, moda, frecuencias, mediana. Elevada significatividad en las respuestas, la mayoría de los alumnos de la escuela-hogar se encuentran escolarizados en centros privados existe un alto grado de cooperación y colaboración entre los alumnos, referida tanto al ámbito escolar como personal, existe una relación de confianza y afectividad entre los alumnos y sus padres, aunque los alumnos desean estar más tiempo en su compañía, los alumnos ven en los maestros una actitud de ayuda y colaboración, importancia de la escuela-hogar en la vida de los alumnos, poca preocupación por parte de los padres de la formación de sus hijos. Es mayor la actitud afectivo-social de estos niños que el rendimiento académico. Los alumnos de la escuela-hogar presentan unas peculiaridades muy específicas de cooperación, colaboración y unión entre ellos.

Análisis evolutivo de la empatía y la amistad como variables mediadoras de los comportamientos de ayuda y cooperación entre niños y adolescentes.

Analizar las variables que influyen en el comportamiento altruista y prosocial desde una perpectiva evolutiva, examinar los modelos diseñados por los distintos autores mostrando su apoyo empírico y plantear un modelo que establezca las relaciones casuales que vinculan a las distintas variables estudiadas. Niños y niñas de de 10 a 14 años de edad. Estudio previo de los instrumentos de evaluación de la empatía, estudio de la empatía como variable mediadora del comportamiento de ayuda en niños de 14 años. Estudio de las variables mediadoras del comportamiento de ayuda en niños de 13 años. Estudio de la empatía y la amistad como variables mediadores de los comportamientos de ayuda y cooperación en niños de 10 y 14 años. Pruebas sociométricas; cuestionarios de empatía; presentación de historias donde de exploran los sentimientos de felicidad, tristeza, miedo y enfado; autoinforme de respuesta emocional. Modelos de ecuaciones estructurales, coeficientes de determinación, coeficientes de correlación múltiple. Las mujeres manifestaron una empatía disposicional mayor que los hombres, en cuanto a las variables exógenas, al igual que respecto a la ayuda de los indicadores observacionales enternecido son los que recogieron mejor los sentimientos empáticos manifestados por los sujetos tras las condiciones experimentales. Con respecto al segundo estudio la motivación de ayuda que produce la ansiedad, sería egoísta porque el objetivo de la ayuda es evitar el propio estado emocional desagradable. El comportamiento cooperativo de los amigos fue provocado por la empatía, mientras que el mismo comportamiento en las parejas de rechazados fue facilitado por la ansiedad. La empatía y la ansiedad producen diferentes consecuencias motivacionales: la ansiedad evoca una respuesta emocional egoísta para reducir la propia actuacion aversiva, mientras que la empatía elicita una motivación altruista cuyo objeto final parece ser reducir el estado de necesidad del otro.