35 research outputs found
Fast-timing measurements in the ground-state band of 114Pd
Using a hybrid Gammasphere array coupled to 25 LaBr3(Ce) detectors, the lifetimes of the first three levels
of the yrast band in 114Pd, populated via 252Cf decay, have been measured. The measured lifetimes are τ2+ =
103(10) ps, τ4+ = 22(13) ps, and τ6+ 10 ps for the 2+
1 , 4+
1 , and 6+
1 levels, respectively. Palladium-114 was
predicted to be the most deformed isotope of its isotopic chain, and spectroscopic studies have suggested it
might also be a candidate nucleus for low-spin stable triaxiality. From the lifetimes measured in this work,
reduced transition probabilities B(E2; J → J − 2) are calculated and compared with interacting boson model,
projected shell model, and collective model calculations from the literature. The experimental ratio RB(E2) =
B(E2; 4+
1 → 2+
1 )/B(E2; 2+
1 → 0+
1 ) = 0.80(42) is measured for the first time in 114Pd and compared with the
known values RB(E2) in the palladium isotopic chain: the systematics suggest that, for N = 68, a transition from
γ -unstable to a more rigid γ -deformed nuclear shape occurs.This work was financially supported by the Science
and Technology Facility Council (STFC) Grants
No. ST/L005840/1, No. ST/L005743/1, and No.
ST/G000751/1. This work has also been partially supported
by the U.S. Department of Energy, Office of Science, Office of
Nuclear Physics under Contract No. DE-AC02-06CH11357
(ANL). E.R.G. would like to acknowledge the STFC for
funding via his Ph.D. studentship. D.J.H. acknowledges
the National Science Foundation, Grant No. PHY-1502092.
E.A.S. and O.Y. would like to acknowledge the project
DFNI-E02/6
Low incidence of Permanent Complications During Catheter Ablation for Atrial Fibrillation using open irrigated catheters: a multicenter registry
Fast-Timing measurements in 100zr using labr3(ce) detectors coupled with gammasphere
In order to investigate the evolution of nuclear deformation in the region of the chart of nuclides around mass numbers A ' 110 and A ' 150, an experiment was performed at the Argonne National Laboratory where the gamma-decay radiation emitted from the fission fragments of 252Cf was measured using 51 Gammasphere detectors coupled with 25 LaBr3(Ce) detectors. In this work, a short description of the experimental setup is presented together with some preliminary results from the fast-Timing analysis of the 4+ state of the nucleus 100Zr. A lifetime value of τ = 50(28) ps was obtained using the Generalized Centroid Shift Method. This result agrees with the literature value of τ = 53(4) ps within one standard deviation.UK authors acknowledge the support of the Science and Technology Facilities Council (STFC). E. Stefanova and O. Yordanov acknowledge support
from BNSF under contract DFNI-E02/6
Low incidence of permanent complications during catheter ablation for atrial fibrillation using open-irrigated catheters: A multicentre registry
Aims Despite catheter ablation (CA) has become an accepted treatment option for symptomatic, drug-resistant atrial fibrillation (AF), the safety of this procedure continues to be cause for concern. The aim of the present study was to assess the incidence of complications with permanent sequelae of CA for AF using open-irrigated catheters in a contemporary, unselected population of consecutive patients. Methods and results From 1 January 2011 to 31 December 2011, data from 2167 consecutive patients who underwent CA for AF using an open-irrigated catheter in 29 Italian centres were collected. All the complications occurring to the patient from admission to the 30th post-procedural day were recorded. No procedure-related death was observed. Complications occurred in 81 patients (3.7%): 46 patients (2.1%) suffered vascular access complications; 13 patients (0.6%) cardiac tamponade, successfully drained in all the cases; six patients (0.3%) arterial thromboembolism (four transient ischaemic attack and two ischaemic strokes); five (0.2%) patients conservatively treated pericardial effusion; three patients (0.1%) phrenic nerve paralysis; three patients (0.1%) pericarditis; three patients (0.1%) haemothorax, and two patients (0.1%) other isolated adverse events. At multivariate analysis, only female sex [odds ratio (OR) 2.5, confidence interval (CI): 1.5-3.7, P < 001] and the operator experience (OR 0.5, CI: 0.4-0.7, P < 001) related to the complications. Only five (0.2%) patients developed permanent sequelae from their complications. Conclusion Catheter ablation for AF with the use of open-irrigated catheters is currently affected by a very low rate of complications leading to permanent sequelae. \uc2\ua9 2014 Published on behalf of the European Society of Cardiology
The mutable nature of particle-core excitations with spin in the one-valence-proton nucleus ¹³³Sb
The γ-ray decay of excited states of the one-valence-proton nucleus ¹³³Sb has been studied using cold-neutron induced fission of ²³⁵U and ²⁴¹Pu targets, during the EXILL campaign at the ILL reactor in Grenoble. By using a highly efficient HPGe array, coincidences between γ-rays prompt with the fission event and those delayed up to several tens of microseconds were investigated, allowing to observe, for the first time, high-spin excited states above the 16.6 μs isomer. Lifetimes analysis, performed by fast-timing techniques with LaBr₃(Ce) scintillators, revealed a difference of almost two orders of magnitude in B(M1) strength for transitions between positive-parity medium-spin yrast states. The data are interpreted by a newly developed microscopic model which takes into account couplings between core excitations (both collective and non-collective) of the doubly magic nucleus ¹³²Sn and the valence proton, using the Skyrme effective interaction in a consistent way. The results point to a fast change in the nature of particle-core excitations with increasing spin
Is the prognosis and course of acral melanoma related to site-specific clinicopathological features?
Acral melanoma is an uncommon type of melanoma in Caucasian patients. However, acral melanoma is the most common type of melanoma in African and Asian patients. Comparison analyses between hand-acral melanoma and foot-acral melanoma have been rarely reported in the literature. Acral melanoma is an uncommon melanocytic tumor characterized by an intrinsic aggressiveness, with specific histological and clinicopathological features. Acral melanoma involves the palms, soles and sub-ungueal sites.
PATIENTS AND METHODS:
A total of 244 patients with acral melanoma were included in our analysis. The current study was performed in three different medical centers: Sapienza University of Rome, San Gallicano Institute of Rome and University of Magna Graecia (Italy). The Kaplan-Meier product was used to estimate survival curves for disease-free survival and overall survival. The log-rank test was used to evaluate differences between the survival curves. Assuming that the effects of the predictor variables are constant over time, the independent predictive factors were assessed by Spearman's test and subsequently data were analyzed performing Cox proportional-hazard regression.
RESULTS:
In both univariate and multivariate analyses Breslow thickness (p < 0.0001) and ulceration (p = 0.003) remained the main predictors. General BRAF mutation was detected in 13.8% of cases. We found that median Breslow value and the percentage of recurrences were similar in hand-acral melanoma and foot-acral melanoma, as well as there were no differences in both short and long-term.
CONCLUSIONS:
The absence of differences in survival between hand-acral melanoma and foot-acral melanoma shows that the aggressiveness of the disease is related to distinct mutational rate, as well as to anatomical site-specific features, rather than to the visibility of the primar