160 research outputs found

    Boson-conserving one-nucleon transfer operator in the interacting boson model

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    The boson-conserving one-nucleon transfer operator in the interacting boson model (IBA) is reanalyzed. Extra terms are added to the usual form used for that operator. These new terms change generalized seniority by one unit, as the ones considered up to now. The results obtained using the new form for the transfer operator are compared with those obtained with the traditional form in a simple case involving the pseudo-spin Bose-Fermi symmetry UB(6)UF(12)U^{B}(6) \otimes U^F(12) in its UBF(5)UF(2)U^{BF}(5) \otimes U^F(2) limit. Sizeable differences are found. These results are of relevance in the study of transfer reactions to check nuclear supersymmetry and in the description of (\beta)-decay within IBA.Comment: 13 pages, 1 table, 0 figures. To be published in Phys. Rev.

    Progressive modulation of resting-state brain activity during neurofeedback of positive-social emotion regulation networks

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    Neurofeedback allows for the self-regulation of brain circuits implicated in specific maladaptive behaviors, leading to persistent changes in brain activity and connectivity. Positive-social emotion regulation neurofeedback enhances emotion regulation capabilities, which is critical for reducing the severity of various psychiatric disorders. Training dorsomedial prefrontal cortex (dmPFC) to exert a top-down influence on bilateral amygdala during positive-social emotion regulation progressively (linearly) modulates connectivity within the trained network and induces positive mood. However, the processes during rest that interleave the neurofeedback training remain poorly understood. We hypothesized that short resting periods at the end of training sessions of positive-social emotion regulation neurofeedback would show alterations within emotion regulation and neurofeedback learning networks. We used complementary model-based and data-driven approaches to assess how resting-state connectivity relates to neurofeedback changes at the end of training sessions. In the experimental group, we found lower progressive dmPFC self-inhibition and an increase of connectivity in networks engaged in emotion regulation, neurofeedback learning, visuospatial processing, and memory. Our findings highlight a large-scale synergy between neurofeedback and resting-state brain activity and connectivity changes within the target network and beyond. This work contributes to our understanding of concomitant learning mechanisms post training and facilitates development of efficient neurofeedback training

    Overconstrained estimates of neutrinoless double beta decay within the QRPA

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    Estimates of nuclear matrix elements for neutrinoless double beta decay (0nu2beta) based on the quasiparticle random phase approximations (QRPA) are affected by theoretical uncertainties, which can be substantially reduced by fixing the unknown strength parameter g_pp of the residual particle-particle interaction through one experimental constraint - most notably through the two-neutrino double beta decay (2nu2beta) lifetime. However, it has been noted that the g_pp adjustment via 2\nu2\beta data may bring QRPA models in disagreement with independent data on electron capture (EC) and single beta decay (beta^-) lifetimes. Actually, in two nuclei of interest for 0nu2beta decay (Mo-100 and Cd-116), for which all such data are available, we show that the disagreement vanishes, provided that the axial vector coupling g_A is treated as a free parameter, with allowance for g_A<1 (``strong quenching''). Three independent lifetime data (2nu2beta, EC, \beta^-) are then accurately reproduced by means of two free parameters (g_pp, g_A), resulting in an overconstrained parameter space. In addition, the sign of the 2nu2beta matrix element M^2nu is unambiguously selected (M^2nu>0) by the combination of all data. We discuss quantitatively, in each of the two nuclei, these phenomenological constraints and their consequences for QRPA estimates of the 0nu2beta matrix elements and of their uncertainties.Comment: Revised version (27 pages, including 10 figures), focussed on Mo-100 and Cd-116. To appear in J. Phys. G: Nucl. Phys. (2008

    Cute Balloons with Thickness

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    Based on the fnite element method, we present a simple volume-preserved thin shell deformation algorithm to simulate the process of inflating a balloon. Diff erent from other thin shells, the material of balloons has special features: large stretch, small bend and shear, and incompressibility. Previous deformation methods often focus on typical three-dimensional models or thin plate models such as cloth model. The rest thin shell methods are complex or ignore the special features of thin shells especially balloons. We modify the triangle element to simple three-prism element, ignore bending and shearing deformation, and use volume preservation algorithm to match the incompressibility of balloons. Simple gas model is used, which interacts with shells to make the balloons inflated. Di different balloon examples have been tested in our experiments and the results are compared with those of other methods. The experiments show that our algorithm is simple and effective

    Identifying risk factors for progression to critical care admission and death among individuals with acute pancreatitis : a record linkage analysis of Scottish healthcare databases

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    This study was commissioned by GSK through the Farr Institute/SHIP/eDRIS single portal. DJM is a Clinician Scientist Fellow funded by the Health Foundation/Academy of Medical Sciences.Objectives: Acute pancreatitis (AP) can initiate systemic complications that require support in critical care (CC). Our objective was to use the unified national health record to define the epidemiology of AP in Scotland, with a specific focus on deterministic and prognostic factors for CC admission in AP. Setting: Health boards in Scotland (n=4). Participants: We included all individuals in a retrospective observational cohort with at least one episode of AP (ICD10 code K85) occurring in Scotland from 1 April 2009 to 31 March 2012. 3340 individuals were coded as AP. Methods: Data from 16 sources, spanning general practice, community prescribing, Accident and Emergency attendances, hospital in-patient, CC and mortality registries, were linked by a unique patient identifier in a national safe haven. Logistic regression and gamma models were used to define independent predictive factors for severe AP (sAP) requiring CC admission or leading to death. Results: 2053 individuals (61.5% (95% CI 59.8% to 63.2%)) met the definition for true AP (tAP). 368 patients (17.9% of tAP (95% CI 16.2% to 19.6%)) were admitted to CC. Predictors of sAP were pre-existing angina or hypertension, hypocalcaemia and age 30-39 years, if type 2 diabetes mellitus was present. The risk of sAP was lower in patients with multiple previous episodes of AP. In-hospital mortality in tAP was 5.0% (95% CI 4.1% to 5.9%) overall and 21.7% (95% CI 19.9% to 23.5%) in those with tAP necessitating CC admission. Conclusions: National record-linkage analysis of routinely collected data constitutes a powerful resource to model CC admission and prognosticate death during AP. Mortality in patients with AP who require CC admission remains high.Publisher PDFPeer reviewe

    Gamow-Teller Strength in the Region of 100^{100}Sn

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    New calculations are presented for Gamow-Teller beta decay of nuclei near 100^{100}Sn. Essentially all of the 100^{100}Sn Gamow-Teller decay strength is predicted to go to a single state at an excitation energy of 1.8 MeV in 100^{100}In. The first calculations are presented for the decays of neighboring odd-even and odd-odd nuclei which show, in contrast to 100^{100}Sn, surprisingly complex and broad Gamow-Teller strength distributions. The results are compared to existing experimental data and the resulting hindrance factors are discussed.Comment: 12 pages (latex) and 2 figures available on reques
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