111 research outputs found

    Mean field study of structural changes in Pt isotopes with the Gogny interaction

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    The evolution of the nuclear shapes along the triaxial landscape is studied in the Pt isotopic chain using the selfconsistent Hartree-Fock-Bogoliubov approximation based on the Gogny interaction. In addition to the parametrization D1S, the new incarnations D1N and D1M of this force are also included in our analysis to asses to which extent the predictions are independent of details of the effective interaction. The considered range of neutron numbers 88<N<26 includes prolate, triaxial, oblate and spherical ground state shapes and serves for a detailed comparison of the predictions obtained with the new sets D1N and D1M against the ones provided by the standard parametrization Gogny-D1S in a region of the nuclear landscape for which experimental and theoretical fingerprints of shape transitions have been found. Structural evolution along the Pt chain is discussed in terms of the deformation dependence of single particle energies.Comment: 18 pages, 10 figures. Accepted for publication in Phys. Rev.

    Role of triaxiality in the ground state shape of neutron rich Yb, Hf, W, Os, and Pt isotopes

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    The evolution of the ground-state shape along the triaxial landscape of several isotopes of Yb, Hf, W, Os, and Pt is analyzed using the self-consistent Hartree-Fock-Bogoliubov approximation. Two well reputed interactions (Gogny D1S and Skyrme SLy4) have been used in the study in order to asses to which extent the results are independent of the details of the effective interaction. A large number of even-even nuclei, with neutron numbers from N=110 up to N=122 has been considered, covering in this way a vast extension of the nuclear landscape where signatures of oblate-prolate shape transitions have already manifested both theoretically and experimentally.Comment: 21 pages, 8 figure

    Proton-neutron quadrupole interactions: an effective contribution to the pairing field

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    We point out that the proton-neutron energy contribution, for low multipoles (in particular for the quadrupole component), effectively renormalizes the strength of the pairing interaction acting amongst identical nucleons filling up a single-j or a set of degenerate many-j shells. We carry out the calculation in lowest-order perturbation theory. We perform a study of this correction in various mass regions. These results may have implications for the use of pairing theory in medium-heavy nuclei and for the study of pairing energy corrections to the liquid drop model when studying nuclear masses.Comment: 19 pages, TeX, 3 tables, 2 figures. Accepted in PR

    E(5), X(5), and Prolate to Oblate Shape Phase Transitions in Relativistic Hartree Bogoliubov Theory

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    Relativistic mean field theory with the NL3 force is used for producing potential energy surfaces (PES) for series of isotopes suggested as exhibiting critical point symmetries. Relatively flat PES are obtained for nuclei showing the E(5) symmetry, while in nuclei corresponding to the X(5) case, PES with a bump are obtained. The PES corresponding to the Pt chain of isotopes suggest a transition from prolate to oblate shapes at 186-Pt.Comment: 21 pages, LaTeX, including 14 .eps figure

    Synchronous Laparoscopic Radical Nephrectomy Left and Contralateral Right Hemicolectomy during the Same Endoscopic Procedure

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    Synchronous renal cell carcinoma in patients with colorectal carcinoma is reported in various percentages ranging from 0.03 up to 4.85% (Halak et al. (2000), Capra et al. (2003)). When surgical treatment is indicated usually two separate operations are planned for resection. In open surgery, in such cases simultaneous resection is recommended if possible. Few reports have described the resection of colorectal and renal cell carcinoma in a single laparoscopic procedure. We have shown that combining left radical nephrectomy and right hemicolectomy is technically feasible, safe and that overall operative time can be limited. In our case operative time was 210 minutes, blood loss 100 milliliters, and duration of hospital stay was 8 days. Adequate port placement, preoperative scheduling, and surgical experience are essential to achieve this goal

    Type of treatment, symptoms and patient satisfaction play an important role in primary care contact during prostate cancer follow-up:Results from the population-based PROFILES registry

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    BACKGROUND: With the increasing attention for the role of General Practitioners (GPs) after cancer treatment, it is important to better understand the involvement of GPs following prostate cancer treatment. This study investigates factors associated with GP contact during follow-up of prostate cancer survivors, such as patient, treatment and symptom variables, and satisfaction with, trust in, and appraised knowledge of GPs. METHODS: Of 787 prostate cancer survivors diagnosed between 2007 and 2013, and selected from the Netherlands Cancer Registry, 557 (71%) responded to the invitation to complete a questionnaire. Multivariable logistic regression analyses were performed to investigate which variables were associated with GP contact during follow- up. RESULTS: In total, 200 (42%) prostate cancer survivors had contact with their GP during follow-up, and 76 (16%) survivors preferred more contact. Survivors who had an intermediate versus low educational level (OR = 2.0) were more likely to have had contact with their GP during follow-up. Survivors treated with surgery (OR = 2.8) or hormonal therapy (OR = 3.5) were also more likely to seek follow-up care from their GP compared to survivors who were treated with active surveillance. Patient reported bowel symptoms (OR = 1.4), hormonal symptoms (OR = 1.4), use of incontinence aids (OR = 1.6), and being satisfied with their GP (OR = 9.5) were also significantly associated with GP contact during follow-up. CONCLUSIONS: Education, treatment, symptoms and patient satisfaction were associated with GP contact during prostate cancer follow-up. These findings highlight the potential for adverse side-effects to be managed in primary care. In light of future changes in cancer care, evaluating prostate cancer follow-up in primary care remains important

    Differentiating acute from chronic insomnia with machine learning from actigraphy time series data

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    Acute and chronic insomnia have different causes and may require different treatments. They are investigated with multi-night nocturnal actigraphy data from two sleep studies. Two different wrist-worn actigraphy devices were used to measure physical activities. This required data pre-processing and transformations to smooth the differences between devices. Statistical, power spectrum, fractal and entropy analyses were used to derive features from the actigraphy data. Sleep parameters were also extracted from the signals. The features were then submitted to four machine learning algorithms. The best performing model was able to distinguish acute from chronic insomnia with an accuracy of 81%. The algorithms were then used to evaluate the acute and chronic groups compared to healthy sleepers. The differences between acute insomnia and healthy sleep were more prominent than between chronic insomnia and healthy sleep. This may be associated with the adaptation of the physiology to prolonged periods of disturbed sleep for individuals with chronic insomnia. The new model is a powerful addition to our suite of machine learning models aiming to pre-screen insomnia at home with wearable devices

    The effective force NL3 revisited

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    Covariant density functional theory based on the relativistic mean field (RMF) Lagrangian with the parameter set NL3 has been used in the last ten years with great success. Now we propose a modification of this parameter set, which improves the description of the ground state properties of many nuclei and simultaneously provides an excellent description of excited states with collective character in spherical as well as in deformed nuclei.Comment: 8 pages, 5 figure

    Intruder bands and configuration mixing in the lead isotopes

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    A three-configuration mixing calculation is performed in the context of the interacting boson model with the aim to describe recently observed collective bands built on low-lying 0+0^+ states in neutron-deficient lead isotopes. The configurations that are included correspond to the regular, spherical states as well as two-particle two-hole and four-particle four-hole excitations across the Z=82 shell gap.Comment: 20 pages, 4 figures, accepted by PRC, reference added for section 1 in this revised versio
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