Connecting the X(5)-β2\beta^2, X(5)-β4\beta^4, and X(3) models to the shape/phase transition region of the interacting boson model

The parameter independent (up to overall scale factors) predictions of the X(5)-$\beta^2$, X(5)-$\beta^4$, and X(3) models, which are variants of the X(5) critical point symmetry developed within the framework of the geometric collective model, are compared to two-parameter calculations in the framework of the interacting boson approximation (IBA) model. The results show that these geometric models coincide with IBA parameters consistent with the phase/shape transition region of the IBA for boson numbers of physical interest (close to 10). Nuclei within the rare-earth region and select Os and Pt isotopes are identified as good examples of X(3), X(5)-$\beta^2$, and X(5)-$\beta^4$ behavior

Systematics of 2+ states in semi-magic nuclei

We propose a simple systematics of low lying 2+ energy levels and electromagnetic transitions in semi-magic isotopic chains Z=28,50,82 and isotonic chains N=28,50,82,126. To this purpose we use a two-level pairing plus quadrupole Hamiltonian, within the spherical Quasiparticle Random Phase Approximation (QRPA). We derive a simple relation connecting the 2+ energy with the pairing gap and quadrupole-quadupole (QQ) interaction strength. It turns out that the systematics of energy levels and B(E2) values predicted by this simple model is fulfilled with a reasonable accuracy by all available experimental data. Both systematics suggest that not only active nucleons but also those filling closed shells play an important role

Band structure from random interactions

The anharmonic vibrator and rotor regions in nuclei are investigated in the framework of the interacting boson model using an ensemble of random one- and two-body interactions. We find a predominance of L(P)=0(+) ground states, as well as strong evidence for the occurrence of both vibrational and rotational band structures. This remarkable result suggests that such band structures represent a far more general (robust) property of the collective model space than is generally thought.Comment: 5 pages, 4 figures, Phys. Rev. Lett., in pres

Transition from the Seniority to the Anharmonic Vibrator Regime in Nuclei

A recent analysis of experimental energy systematics suggests that all collective nuclei fall into one of three classes -- seniority, anharmonic vibrational, or rotational -- with sharp phase transitions between them. We investigate the transition from the seniority to the anharmonic vibrator regime within a shell model framework involving a single large j-orbit. The calculations qualitatively reproduce the observed transitional behavior, both for U(5) like and O(6) like nuclei. They also confirm the preeminent role played by the neutron-proton interaction in producing the phase transition.Comment: 9 pages with 2 tables, submitted to Physical Review C, November 199

Universal correlations of nuclear observables and new signatures of structure in exotic nuclei: A review

Recently, several nearly universal correlations of nuclear observables, spanning nuclei from singly magic to rotor, have been discovered. The simple global behavior revealed by these correlations discloses new signatures of structure that require a knowledge only of the energies of the first two excited states in even-even nuclei and the B(E2 : 2{sub 1}{sup +} {yields} 0{sub 1}{sup +}) value. Since these are the simplest to-obtain data in new nuclei in unexplored regions, they should be especially valuable in radioactive beam studies of nuclei far from stability where the data will necessarily be sparse compared to that with which is accustomed. This report reviews some of these recent developments

Universal Correlations of Nuclear Observables and the Structure of Exotic Nuclei

Despite the apparent complexity of nuclear structural evolution, recent work has shown a remarkable underlying simplicity that is unexpected, global, and which leads to new signatures for structure based on the easiest-to-obtain data. As such they will be extremely valuable for use in the experiments with low intensity radioactive beams. Beautiful correlations based either on extrinsic variables such as N{sub p}N{sub n} or the P-factor or correlations between collective observables themselves have been discovered. Examples to be discussed include a tri-partite classification of structural evolution, leading to a new paradigm that discloses certain specific classes of nuclei, universal trajectories for B(E2: w{sub 1}{sup +} {r_arrow} 0{sub 1}{sup +}) values and their use in extracting hexadecapole deformations from this observable alone, the use of these B(E2) values to identify shell gaps and magic numbers in exotic nuclei, the relationship of {beta} and {gamma} deformations, and single nucleon separation energies. Predictions for nuclei far off stability by interpolation will also be discussed

Liver procurement as part of multiple organ procurement

Departamentul de Chirurgie Generală şi Transplant Hepatic “Dan Setlacec”, Institutul Clinic Fundeni, Bucureşti, România, Al XII-lea Congres al Asociației Chirurgilor „Nicolae Anestiadi” din Republica Moldova cu participare internațională 23-25 septembrie 2015Scop: Prelevarea hepatică, etapă premergătoare transplantului hepatic, parte din prelevarea multiorgan, contribuie prin acuratețea și corectitudinea intervenției la obținerea unei grefe hepatice de bună calitate cu rezultate bune ale transplantului atît imediate cât și pe termen lung. Lucrarea de față își propune să evidențieze importantul rol al identificării variantelor anatomice și adaptarea metodelor de prelevare în funcție de acestea.Material şi metode: Pe parcursul perioadei 1 ianuarie 2000-16 iunie 2015 s-au efectuat în Centrul nostru 666 prelevări multiorgan. O importanță deosebită a fost acordată recunoașterii variantelor anatomice arteriale, acestea adaugând un grad de dificultate procedurii, dar fiind totodată esențiale pentru asigurarea succesului intervenției. Rezultate: Caracteristicile heterogene ale donatorilor au obligat la aplicarea unei game variate de tehnici de prelevare, adaptate fiecărei situații, așa cum au fost descrise în lucrarea de față, un pas cheie pentru obținerea unei grefe viabile pentru transplant. Concluzii: Multiplele tehnici de prelevare hepatică pot fi aplicate cu succes când sunt adaptate fiecarui donator, scurtând timpul de prelevare și furnizând o grefă de cea mai bună calitate.Purpose: Liver procurement, the preliminary stage of liver transplantation, is a part of multi-organ procurement, and it contributes, with its accuracy and correctness to the high quality liver graft, with the best results in the transplantation process (both immediate and long term). This paper is framed to enlighten the important role of identification of anatomical variants and the selection of the procurement technique that suits most. Material and methods: During 1st Jan 2000-16th Jun 2015 a number of 666 multi-organ procurements were performed in our center. A special attention was paid in recognizing of anatomical variants of blood vessels (especially arterial blood vessels), which added a high degree of difficulty to the procedures, but was considered to be vital in order to ensure the success of the intervention. Results: Heterogeneous characteristics of donors imposed the implementation of a variety of sampling techniques, adapted on each situation as was described in the paper, an essential step to obtain a viable liver / organ graft suitable for the transplant. Conclusions: The multiple methods of liver procurement can be successfully applied when it is adapted to each of the donors, thus shortening the actual time of the liver harvesting, delivering the best quality of the new liver graft

Possible experimental signature of octupole correlations in the 02+^+_2 states of the actinides

$J^{\pi}$= 0$^+$ states have been investigated in the actinide nucleus ${}^{240}$Pu up to an excitation energy of 3 MeV with a high-resolution (p,t) experiment at $E_{p}$= 24 MeV. To test the recently proposed $J^{\pi}$= 0$^+_2$ double-octupole structure, the phenomenological approach of the spdf-interacting boson model has been chosen. In addition, the total 0$^+$ strength distribution and the $0^+$ strength fragmentation have been compared to the model predictions as well as to the previously studied (p,t) reactions in the actinides. The results suggest that the structure of the 0$^+_2$ states in the actinides might be more complex than the usually discussed pairing isomers. Instead, the octupole degree of freedom might contribute significantly. The signature of two close-lying 0$^+$ states below the 2-quasiparticle energy is presented as a possible manifestation of strong octupole correlations in the structure of the 0$^+_2$ states in the actinides.Comment: 6 pages, 5 figures, published in Phys. Rev. C 88, 041303(R) (2013