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We investigate geometric configurations of α ( 4 He nucleus) clusters in the second J π = 2 + state of 12 C, which has been discussed as a rotational band member of the second 0 + state, the Hoyle state. The ground and excited 0 + and 2 + states are described by a three- α cluster model. The three-body Schrödinger equation with orthogonality conditions is accurately solved by the stochastic variational method with correlated Gaussian basis functions. To analyse the structure of these resonant states in a convenient form, we introduce a confining potential. The two-body density distributions together with the spectroscopic information clarify the structure of these states. We find that main configurations of both the second 0 + and 2 + states are acute-angled triangle shapes originating from the 8 Be( 0 + ) + α configuration. However, the 8 Be + α components in the second 2 + state become approximately 2/3 because the 8 Be subsystem is hard to excite, indicating that the state is not an ideal rigid rotational band member of the Hoyle state. [ABSTRACT FROM AUTHOR]

We study an exactly solvable algebraic Hamiltonian for odd systems that allows to span the whole range between prolate and oblate spectra, while maintaining the S U BF (3) ⊗ U s F (2) dynamical symmetry, thanks to the mixing of quadratic and cubic Casimir operators of S U BF (3) . We choose a j = 1 / 2 , 3 / 2 , and 5 / 2 fermionic basis that is coupled to coherent states for the boson part. With this, we diagonalize the Boson–Fermion Hamiltonian obtaining potential energy surfaces for each component. We find a very rich variety of behaviours: the various orbitals do not display the same shape, some are prolate, while others are oblate, and they make the transition following different paths. [ABSTRACT FROM AUTHOR]

In this contribution, the motivations for a Focus Point on the future nuclear physics researches in the Italian laboratories are described. The organization of the preliminary workshops and of the final reports in this series is described. [ABSTRACT FROM AUTHOR]

Geometric configurations of three α particles in the ground- and first-excited J π = 0 + states of 12 C are discussed within two types of α -cluster models which treat the Pauli principle differently. Though there are some quantitative differences especially in the internal region of the wave functions, equilateral triangle configurations are dominant in the ground state, while in the first excited 0 + state isosceles triangle configurations dominate, originating from 8 Be + α configurations. [ABSTRACT FROM AUTHOR]

The elastic scattering in the reaction 7 Li+ 208 Pb was investigated in the bombarding energy range from 25 to 39 MeV. The real and imaginary parts of the optical potential were analyzed by using a phenomenological potential. A dispersion relation analysis is presented in order to investigate the threshold anomaly effect. It is concluded that 7 Li has an intermediate behavior between the tightly bound nuclei such as 16 O and the loosely bound nuclei such as 6 Li where the lack of the threshold anomaly is unambiguously observed. Reaction cross sections are also extracted from the elastic scattering data and its comparison with the ones of other systems has been performed to draw hints on the effect of the breakup channel. [ABSTRACT FROM AUTHOR]

The quantum shape phase transitions in odd-even nuclei are investigated within the intrinsic frame approach to the interacting boson-fermion model. In this work, the case of a single-j fermion coupled to a bosonic core that performs a transition from prolate to oblate shapes is considered. The focus is on the effect of the coupled fermion on the whole system along the transitional path from prolate to oblate shapes, passing through the γ -unstable shape. One could expect that all the magnetic substates of the coupled single-fermion with j = 9 / 2 would be driven by the shape of the bosonic core. However, the present work shows that the odd-fermion follows some unexpected and unique paths. The five-components of the j = 9 / 2 orbital do show quite interesting and diverse behaviour. Two of them move slowly from the prolate to the oblate shape by venturing into the triaxial region and also show γ -softness around their slow shape-changing region. The other three odd-states show sudden jumps from prolate side to oblate side and shape coexistence appears, although one of them is fairly close to γ -instability. These unexpected situations make this shape phase transition worth of investigation and discussion. [ABSTRACT FROM AUTHOR]

The exotic, neutron-rich and weakly-bound isotope 29F stands out as a waymarker on the southern shore of the island of inversion, a portion of the nuclear chart where the effects of nuclear forces lead to a reshuffling of the single particle levels and to a reorganization of the nuclear structure far from stability. This nucleus has become very popular, as new measurements allow to refine theoretical models. We review the latest developments and suggest how to further assess the structure by proposing predictions on electromagnetic transitions that new experiments of Relativistic Coulomb Excitation should soon become able to measure. The neutron-rich, weakly bound fluorine isotope 29F has been extensively investigated theoretically, but its significance has been revived by recent experiments. The authors present the latest developments and make prediction on the electromagnetic transitions occurring in this isotope that may be observed in the near future. [ABSTRACT FROM AUTHOR]

We give an account of the main achievements of the scientific career of Andrea Vitturi so far, that have recently been discussed during the workshop "Theoretical Nuclear Physics in Padova" on the occasion of his retirement from full professor at the University of Padova. He has oftentimes been the driving force behind numerous contributions to nuclear structure and nuclear reactions that are here reviewed: giant resonances, pairing correlations, collective modes, algebraic models, inelastic excitations, electromagnetic response, break-up and transfer reactions, coupled-channel formalism, clustering, sub-barrier fusion processes, etc. Among these topics several inspirational works and ideas can be found that we would like to highlight. [ABSTRACT FROM AUTHOR]

Background:A recent Monographs Working Group of the International Agency for Research on Cancer concluded that there is limited evidence for a causal association between exposure to asbestos and stomach cancer.Methods:We performed a meta-analysis to quantitatively evaluate this association. Random effects models were used to summarise the relative risks across studies. Sources of heterogeneity were explored through subgroup analyses and meta-regression.Results:We identified 40 mortality cohort studies from 37 separate papers, and cancer incidence data were extracted for 15 separate cohorts from 14 papers. The overall meta-SMR for stomach cancer for total cohort was 1.15 (95% confidence interval 1.03-1.27), with heterogeneous results across studies. Statistically significant excesses were observed in North America and Australia but not in Europe, and for generic asbestos workers and insulators. Meta-SMRs were larger for cohorts reporting a SMR for lung cancer above 2 and cohort sizes below 1000.Conclusions:Our results support the conclusion by IARC that exposure to asbestos is associated with a moderate increased risk of stomach cancer. [ABSTRACT FROM AUTHOR]

Background: Prioritising control measures for occupationally related cancers should be evidence based. We estimated the current burden of cancer in Britain attributable to past occupational exposures for International Agency for Research on Cancer (IARC) group 1 (established) and 2A (probable) carcinogens.Methods: We calculated attributable fractions and numbers for cancer mortality and incidence using risk estimates from the literature and national data sources to estimate proportions exposed.Results: 5.3% (8019) cancer deaths were attributable to occupation in 2005 (men, 8.2% (6362); women, 2.3% (1657)). Attributable incidence estimates are 13 679 (4.0%) cancer registrations (men, 10 063 (5.7%); women, 3616 (2.2%)). Occupational attributable fractions are over 2% for mesothelioma, sinonasal, lung, nasopharynx, breast, non-melanoma skin cancer, bladder, oesophagus, soft tissue sarcoma, larynx and stomach cancers. Asbestos, shift work, mineral oils, solar radiation, silica, diesel engine exhaust, coal tars and pitches, occupation as a painter or welder, dioxins, environmental tobacco smoke, radon, tetrachloroethylene, arsenic and strong inorganic mists each contribute 100 or more registrations. Industries and occupations with high cancer registrations include construction, metal working, personal and household services, mining, land transport, printing/publishing, retail/hotels/restaurants, public administration/defence, farming and several manufacturing sectors. 56% of cancer registrations in men are attributable to work in the construction industry (mainly mesotheliomas, lung, stomach, bladder and non-melanoma skin cancers) and 54% of cancer registrations in women are attributable to shift work (breast cancer).Conclusion: This project is the first to quantify in detail the burden of cancer and mortality due to occupation specifically for Britain. It highlights the impact of occupational exposures, together with the occupational circumstances and industrial areas where exposures to carcinogenic agents occurred in the past, on population cancer morbidity and mortality; this can be compared with the impact of other causes of cancer. Risk reduction strategies should focus on those workplaces where such exposures are still occurring. [ABSTRACT FROM AUTHOR]

The mirror isobars 7Li and 7Be are investigated in a dicluster model. The magnetic dipole moments and the magnetic dipole response to the continuum are calculated in this framework. The magnetic contribution is found to be small with respect to electric dipole and quadrupole excitations even at astrophysical energies, at a variance with the case of the deuteron. Energy-weighted molecular sum rules are evaluated and a formula for the molecular magnetic dipole sum rule is found which matches the numerical calculations. Cross-sections for photo-dissociation and radiative capture as well as the S -factor for reactions of astrophysical significance are calculated with good agreement with known experimental data. [ABSTRACT FROM AUTHOR]

We investigate the role of higher multipole excitations in the electromagnetic dissociation of one-neutron halo nuclei within two different theoretical models --a finite-range distorted-wave Born approximation and another in a more analytical method with a finite-range potential. We also show, within a simple picture, how the presence of a weakly bound state affects the breakup cross-section. [ABSTRACT FROM AUTHOR]

The Bohr Hamiltonian, also called collective Hamiltonian, is one of the cornerstones of nuclear physics and a wealth of solutions (analytic or approximated) of the associated eigenvalue equation have been proposed over more than half a century (confining ourselves to the quadrupole degree of freedom). Each particular solution is associated with a peculiar form for the V(β,γ) potential. The large number and the different details of the mathematical derivation of these solutions, as well as their increased and renewed importance for nuclear structure and spectroscopy, demand a thorough discussion. It is the aim of the present monograph to present in detail all the known solutions in γ-unstable and γ-stable cases, in a taxonomic and didactical way. In pursuing this task we especially stressed the mathematical side leaving the discussion of the physics to already published comprehensive material. The paper contains also a new approximate solution for the linear potential, and a new solution for prolate and oblate soft axial rotors, as well as some new formulae and comments. The quasi-dynamical SO(2) symmetry is proposed in connection with the labeling of bands in triaxial nuclei. [ABSTRACT FROM AUTHOR]

The light weakly bound nucleus 7Li is studied within a dicluster α + t picture. Different observables obtained within our simple model are compared with previous calculations and experiments showing good agreement. In particular, we calculate dipole and quadrupole electromagnetic response to the continuum. The energy distribution of B( Eλ) values are consistent with the energy-weighted molecular sum rule and display a sizable contribution of non-resonant character arising from the weak binding property. The corresponding form factors for excitations to the continuum are used in a semiclassical coupled-channel scheme to get estimates for the breakup cross-section in a heavy-ion reaction. The nuclear contribution is found to play an important role in the process for bombarding energies around the Coulomb barrier. The masses and charges ratios of the two clusters are shown to lead to features of the cluster halo that may significantly differ from the one usually associated with one-nucleon haloes. [ABSTRACT FROM AUTHOR]

A theory of light emission in sonoluminescing hydrogen bubbles, based upon transitions in confined atoms, is proposed. Despite the simplicity of the assumptions this model accounts for a number of facts related to sonoluminescence: a broadband spectrum in the correct wavelength window is predicted as well as the number of emitted photons. Taking the temperature at the moment of collapse as a parameter we argue that confined atomic transitions at 4000 K may account for the observed light emission. This result favours a ‘cold’ interpretation of sonoluminescence in contrast to previous theories. Many considerations are qualitatively extendible to rare gases. [ABSTRACT FROM AUTHOR]

The excitation energy above the breakup threshold of the α + d/6Li system, after the interaction of 6Li nuclei with a 208Pb target, was deduced from the invariant mass of the α + d system. Data were collected with a large-solid-angle detector set-up at four beam energies around the Coulomb barrier. The excitation of the 6Li nucleus above the breakup threshold (1.47 MeV) has a quite similar behavior at each measured beam energy and angle; it is peaked at ∼ 1 MeV above the threshold and shows an exponential decay on the high energy side, which is a clear signature of a direct breakup process. The experimental excitation energies are reproduced both in shape and absolute value by 1) fully quantum-mechanical Coupled-Channel calculations with coupling to discretized-continuum 6Li excitations, 2) semi-classical Coupled-Channel approach, where the relative motion is treated along a classical trajectory. [ABSTRACT FROM AUTHOR]

Background:. We describe our experience with exenterative pelvic surgery for colorectal cancer in a small community hospital. Methods:. We retrospectively evaluated 26 consecutive patients (14 women) with locally advanced (n=16) or recurrent (n=10) colorectal adenocarcinomas who underwent pelvic exenterations between August 1990 and December 2001 in our service. Results:. Seventeen patients had posterior pelvic exenteration (PPE), eight had total pelvic exenteration (TPE) and one had TPE with internal hemipelvectomy. Major morbidity occurred in 12 patients (46%), causing 3 deaths (11%) in the immediate postoperative period. Fourteen of 23 patients who survived the immediate postoperative period have relapsed (61%). At a median follow-up of 42 months, the 5-year survival is 38%. Conclusion:. Pelvic exenterative procedures can be offered to patients with bulky or recurrent colorectal carcinomas with adequate results and satisfactory palliation, even in a community setting. [ABSTRACT FROM AUTHOR]

We investigate the possible signature of the presence of giant pairing states at an excitation energy of about 10 MeV via two-particle transfer reactions induced by neutron-rich weakly bound projectiles. Performing particle–particle RPA calculations on [sup 208]Pb and BCS+RPA calculations on [sup 116]Sn, we obtain the pairing strength distribution for two-particle addition and removal modes. Estimates of two-particle transfer cross sections can be obtained in the framework of the macroscopic model. The weak-binding nature of the projectile kinematically favors transitions to high-lying states. In the case of the ([sup 6]He, [sup 4]He) reaction, we predict a population of the Giant Pairing Vibration with cross sections of the order of a millibarn, dominating over the mismatched transition to the ground state.© 2003 MAIK “Nauka / Interperiodica”. [ABSTRACT FROM AUTHOR]

The use of radioactive ion beams is shown to offer the possibility to study collective pairing states at high excitation energy, which are not usually accessible with stable projectiles because of large energy mismatch. In the case of two-neutron stripping reactions induced by 6He, we predict a population of the giant pairing vibration in 208Pb or 116Sn with cross-sections of the order of a millibarn, dominating over the mismatched transition to the ground state. [ABSTRACT FROM AUTHOR]

Erratum to: Unexpected transitional paths in the prolate to oblate shape phase transitions for Bose-Fermi systems Erratum to: Eur. Phys. J. A (2021) 57:2 https://doi.org/10.1140/epja/s10050-020-00308-4 This work was supported by the Scientific and Technical Research Council of Turkey (TÜBITAK), under the project number 119F127, by the Consejería de Economía, Conocimiento, Empresas y Universidad de la Junta de Andalucía (Spain) under Group FQM-160, by the Spanish Ministerio de Ciencia e Innovaciíon, ref. [Extracted from the article]

The structure of 22 C plays a vital role in the new physics at subshell closure of N = 16 in the neutron-rich region. We study the two-neutron correlations in the ground state of the weakly-bound Borromean nucleus 22 C sitting at the edge of the neutron-drip line and its sensitivity to core -n potential. For the present study, we employ a three-body ( core + n + n ) structure model designed for describing the Borromean system by explicit coupling of unbound continuum states of the subsystem ( core + n ). We use a density-independent contact-delta interaction to describe the neutron-neutron interaction and its strength is varied to fix the binding energy. Along with the ground-state properties of 22 C, we investigate its electric-dipole and monopole responses, discussing the contribution of various configurations. Our results indicate more configuration mixing as compared to the previous studies in the ground state of 22 C. However, they strongly depend upon the choice of the 20 C -n potential as well as the binding energy of 22 C, which call for new precise measurements for the low-lying continuum structure of the binary system ( 20 C + n ) and the mass of 22 C. These measurements will be essential to understand the Borromean three-body system 22 C with more accuracy. [ABSTRACT FROM AUTHOR]

The collective Bohr Hamiltonian is solved for the soft triaxial rotor around γ0 = π/6 with a displaced harmonic oscillator potential in γ and a Kratzer-like potential in β. The properties of the spectrum are outlined and a generalization for the more general triaxial case with 0 < γ < π/6 is proposed. [ABSTRACT FROM AUTHOR]