On the difference between proton and neutron spin-orbit splittings in nuclei

The latest experimental data on nuclei at $^{132}$Sn permit us for the first time to determine the spin-orbit splittings of neutrons and protons in identical orbits in this neutron-rich doubly-magic region and compare the case to that of $^{208}$Pb. Using the new results, which are now consistent for the two neutron-rich doubly magic regions, a theoretical analysis defines the isotopic dependence of the mean field spin-orbit potential and leads to a simple explicit expression for the difference between the spin-orbit splittings of neutrons and protons. The isotopic dependence is explained in the framework of different theoretical approaches.Comment: 8 pages, revte

On the isospin dependence of the mean spin-orbit field in nuclei

By the use of the latest experimental data on the spectra of $^{133}$Sb and $^{131}$Sn and on the analysis of properties of other odd nuclei adjacent to doubly magic closed shells the isospin dependence of a mean spin-orbit potential is defined. Such a dependence received the explanation in the framework of different theoretical approaches.Comment: 52 pages, Revtex, no figure

Realistic shell-model calculations for proton particle-neutron hole nuclei around 132Sn

We have performed shell-model calculations for nuclei with proton particles and neutron holes around 132Sn using a realistic effective interaction derived from the CD-Bonn nucleon-nucleon potential. For the proton-neutron channel this is explicitly done in the particle-hole formalism. The calculated results are compared with the available experimental data, particular attention being focused on the proton particle-neutron hole multiplets. A very good agreement is obtained for all the four nuclei considered, 132Sb, 130Sb, 133Te and 131Sb. We predict many low-energy states which have no experimental counterpart. This may stimulate, and be helpful to, future experiments.Comment: 8 pages, 6 figures, to be published on Physical Review

Low momentum nucleon-nucleon potential and shell model effective interactions

A low momentum nucleon-nucleon (NN) potential V-low-k is derived from meson exhange potentials by integrating out the model dependent high momentum modes of V_NN. The smooth and approximately unique V-low-k is used as input for shell model calculations instead of the usual Brueckner G matrix. Such an approach eliminates the nuclear mass dependence of the input interaction one finds in the G matrix approach, allowing the same input interaction to be used in different nuclear regions. Shell model calculations of 18O, 134Te and 135I using the same input V-low-k have been performed. For cut-off momentum Lambda in the vicinity of 2 fm-1, our calculated low-lying spectra for these nuclei are in good agreement with experiments, and are weakly dependent on Lambda.Comment: 5 pages, 5 figure

Human occupation as a complex system

The present work justifies the change in theoretical approach required to use the concepts, principles and methods of artificial intelligence and computational science in order to deal with problems centered in social systems, such as studying the relation between human occupation and social stability and the validation of hypotheses about sociocybernetics strategies applied to governability. In order to model and study human occupation as a complex system, this document describes the autonomous components and the set of behaviors whose simultaneous and concurrent occurrence produce dynamical bifurcations (chaos) and emerging events in the Human Occupation, understood as a complex system between the triad: people - occupations - contexts, which expresses sensitive phenomena, impossible to be known completely and univocally. The components of the occupation are developed conceptually and relations of composition and condition of the given behaviors between these components are established, in order to establish human occupation as a complex system and in such a way that decision making and the prediction of occupational dynamics and behaviors in the individual and social levels can be modeled and simulated

Quadrupole-deformed and octupole collective bands in 228^{228}Ra

Spins and parities for collective states in $^{228}$Ra have been determined from conversion electron measurements with a mini-orange $\beta$-spectrometer. The fast-timing $\beta\gamma\gamma(t)$ method has been used to measure lifetimes of T$_{1/2}$=550(20) ps and 181(3) ps for the $2^{+}_{1}$ and $4^{+}_{1}$ members of the K=0$^{+}$ band, and T$_{1/2} \leqslant$ 7 ps and $\leqslant$ 6 ps for the $1^{-}_{1}$ and $3^{-}_1$ members of the K = $0^{-}$ band, respectively The quadrupole moments, $Q_{0}$ deduced from the B (E2; 2$_{1}^{+} \rightarrow 0_{1}^{+}$) and B (E2; 4$_{1}^{+} \rightarrow 2_1^{+}$) rates are in good agreement with the previously measured value and the systematics of the region. However, the B(E1) rates of $\geqslant$ 4 × 10$^{−4}$ e$^{2}$fm$^{2}$, which represent the first B(E1) measurements for this nucleus, are at least 25 times larger than the value previously suggested for $^{228}$Ra. The new results are consistent with the B(E1) rates recently measured for the neighbouring $^{227}$Ra and reveal octupole correlations in $^{228}$Ra

When does the co-evolution of technology and science overturn into technoscience?

In this paper, the relations between science and technology, intervention and representation, the natural and the artificial are analysed on the background of the formation of modern science in the sixteenth century. Due to the fact that technique has been essential for modern science from its early beginning, modern science is characterised by a hybridisation of knowledge and intervention. The manipulation of nature in order to measure its properties has steadily increased until artificial things have been produced, such as laser beams, chemical compounds, elementary particles. Furthermore, the structural bracing of natural science, technological development, and industrial exploitation of nature go also back to the foundation of modern science. In order to strengthen the debate on technoscience against this background, the specific characteristics of technoscientific objects have to be clarified as have the specific characteristics of the social organisation of technoscience and its performance