68 research outputs found
High-resolution conversion electron spectroscopy of the i 125 electron-capture decay
The conversion electrons from the decay of the 35.5-keV excited state of 125Te following the electron capture
decay of 125I have been investigated at high resolution using an electrostatic spectrometer. The penetration
parameter λ = −1.2(6) and mixing ratio |δ(E2/M1)| = 0.015(2) were deduced by fitting to literature values
and present data. The shake probability of the conversion electrons is estimated to be 0.5, more than two times
larger than the predicted value of 0.2.This research was made possible by an Australian Research
Council Discovery Grant DP140103317. J.T.H.D. acknowledges support of the Australian Government Research Training Program
Spectroscopy and excited-state g factors in weakly collective Cd 111: Confronting collective and microscopic models
Background: The even cadmium isotopes near the neutron midshell have long been considered among the best examples of vibrational nuclei. However, the vibrational nature of these nuclei has been questioned based on E2 transition rates that are not consistent with vibrational excitations. In the neighboring odd-mass nuclei, the g factors of the low-excitation collective states have been shown to be more consistent with a deformed rotational core than a vibrational core. Moving beyond the comparison of vibrational versus rotational models, recent advances in computational power have made shell-model calculations feasible for Cd isotopes. These calculations may give insights into the emergence and nature of collectivity in the Cd isotopes.This research was supported in part by the
Australian Research Council Grants No. DP120101417, No.
DP130104176, No. DP140102986, No. DP140103317, No.
DP170101673, and No. LE150100064. B.J.C., A.A., J.T.H.D.,
M.S.M.G., and T.J.G. acknowledge support of the Australian
Government Research Training Program. Support for the
ANU Heavy Ion Accelerator Facility operations through
the Australian National Collaborative Research Infrastructure
Strategy (NCRIS) program is acknowledged
Perturbed angular distributions with LaBr3 detectors: The g factor of the first 10+ state in Cd 110 reexamined
The time differential perturbed angular distribution technique with LaBr3 detectors has been applied to the Iπ = 11-/2 isomeric state (Ex=846 keV, τ=107 ns) in 107Cd, which was populated and recoil-implanted into a gadolinium host following the 98Mo(^12C, 3n)^107Cd reaction. The static hyperfine field strength of Cd recoil implanted into gadolinium was thus measured, together with the fraction of nuclei implanted into field-free sites, under similar conditions as pertained for a previous implantation perturbed angular distribution g-factor measurement on the Iπ=10+ state in 110Cd. The 110Cdg(10+) value was thereby reevaluated, bringing it into agreement with the value expected for a seniority-two vh11/2 configuration.This research was supported in part by the Australian Research Council Grants No. DP120101417, No.
DP130104176, No. DP140102986, No. DP140103317, No. DP170101673, No. LE150100064, and No. FT100100991, and by The Australian National University Major Equipment Committee Grant No. 15MEC14
Randomized trial evaluating the framing of cardiovascular risk and its impact on blood pressure control [ISRCTN87597585]
BACKGROUND: The format or frame in which the results of randomized trials are presented has been shown to influence health professional's self-reported practice. We sought to investigate the effect of framing cardiovascular risk as two different formats in a randomized trial. METHODS: We recruited 457 patients aged between 60 and 79 years with high blood pressure from 20 family practices in Avon, UK. Patients were randomized to cardiovascular risk presented either as 1) an absolute risk level (AR) or as 2) the number needed to treat to prevent an adverse event (NNT). The main outcome measures were: 1) percentage of patients in each group with a five-year cardiovascular risk ≥ 10%, 2) systolic and diastolic blood pressure, 3) intensity of prescribing of cardiovascular medication. RESULTS: Presenting cardiovascular risk as either an AR or NNT had no impact reducing cardiovascular risk at 12 month follow up, adjusted odds ratio 1.53 (95%CI 0.76 to 3.08). There was no difference between the two groups in systolic (adjusted difference 0.97 mmHg, 95%CI -2.34 mmHg to 4.29 mmHg) or diastolic (adjusted difference 0.70 mmHg, 95%CI -1.05 mmHg to 2.45 mmHg) blood pressure. Intensity of prescribing of blood pressure lowering drugs was not significantly different between the two groups at six months follow up. CONCLUSIONS: Presenting cardiovascular risk in clinical practice guidelines as either an AR or NNT had a similar influence on patient outcome and prescribing intensity. There is no difference in patient outcomes when these alternative formats of risk are used in clinical practice guidelines
Emerging nuclear collectivity in 124-130Te
The emergence of nuclear collectivity near doubly-magic 132Sn was explored along the stable, eveneven 124−130Te isotopes. Preliminary measurements of the B(E2; 41+ → 21+) transition strengths are reported from Coulomb excitation experiments primarily aimed at measuring the g factors of the 41+ states. Isotopically enriched Te targets were excited by 198-205 MeV 58Ni beams. A comparison of transition strengths obtained is made to large-scale shell-model calculations with successes and limitations discussed
Solenogam: A new detector array for γ-ray and conversion-electron spectroscopy of long-lived states in fusion-evaporation products
A new detector array, Solenogam, has been developed at the Australian National University Heavy Ion Accelerator Facility. Coupled initially to the SOLITAIRE 6.5 T, gas-filled, solenoidal separator, and later to an 8 T solenoid, the system enables the study of long-lived nuclear states through -ray and conversion-electron spectroscopy in a low-background environment. The detector system is described and results from the commissioning experiments are presented.The authors are grateful to the academic and technical staff of the
Department of Nuclear Physics (Australian National University) and
the Heavy Ion Accelerator Facility for their continued support. This re-
search was supported by the Australian Research Council through grant
numbers FT100100991, DP120101417, DP14102986, and
DP140103317. M.S.M.G., A.A., B.J.C., J.T.H.D., T.J.G., B.Q.L., and
T.P. acknowledge the support of the Australian Government Research
Training Program. Support for the ANU Heavy Ion Accelerator Facility
operations through the Australian National Collaborative Research
Infrastructure Strategy (NCRIS) program is acknowledge
Evidence for shape coexistence in 52Cr through conversion-electron and pairconversion spectroscopy
Electric monopole (E0) transitions are a highly sensitive probe of the charge distribution of an atomic nucleus. A large E0 transition strength (ρ2(E0)) is a clear indicator of nuclear shape coexistence. In the region between doubly magic 40Ca and 56Ni, E0 transitions have never been observed in the Ti or Cr isotopes, nor in the heavier iron isotopes (56,58Fe). We have performed the first measurements of the E0 transitions in 52Cr via conversion-electron and pair-conversion spectroscopy using the Super-e spectrometer at the Australian National University Heavy Ion Accelerator Facility. We present the first spectra obtained for 52Cr, including the first observation of the E0 transition from the first-excited 0+ state in 52Cr, in both electron-positron pairs and conversion-electron spectroscopy. The preliminary values for the E0 strength in the 1531keV 2+ → 2+ transition in 52Cr is ρ2(E0) � 103 = 470(190), and for the 1728-keV 23+ → 21+ transition, it is ρ2(E0) 103 = 1800(1200). The large E0 strengths observed are consistent with shape coexistence in this region. However, despite the relatively precise observation of the conversion-electron and electron-positron pair intensities, the E0 strengths have large uncertainties. More precise determinations of relevant spectroscopic quantities, such as the state lifetimes and transition mixing ratios for mixed M1 + E2 transitions, are needed to determine the E0 strength more precisely.This research was supported
in part by the Australian Research Council grant numbers DP140102986 and DP170101673, and was partially
supported by the International Joint Research Promotion
Program of Osaka University and JSPS KAKENHI Grant
Number JP17H02893. This work is also based on the research supported partly by National Research Foundation
of South Africa (118645, 90741). J.T.H.D., A.A., B.J.C.,
M.S.M.G., T.J.G., B.P.M., and B.P.E.T. acknowledge support of the Australian Government Research Training Program. Support for the ANU Heavy Ion Accelerator Facility operations through the Australian National Collaborative Research Infrastructure Strategy program is acknowledged
Cost-effectiveness of general practice care for low back pain: a systematic review
Care from a general practitioner (GP) is one of the most frequently utilised healthcare services for people with low back pain and only a small proportion of those with low back pain who seek care from a GP are referred to other services. The aim of this systematic review was to evaluate the evidence on cost-effectiveness of GP care in non-specific low back pain. We searched clinical and economic electronic databases, and the reference list of relevant systematic reviews and included studies to June 2010. Economic evaluations conducted alongside randomised controlled trials with at least one GP care arm were eligible for inclusion. Two reviewers independently screened search results and extracted data. Eleven studies were included; the majority of which conducted a cost-effectiveness or cost-utility analysis. Most studies investigated the cost-effectiveness of usual GP care. Adding advice, education and exercise, or exercise and behavioural counselling, to usual GP care was more cost-effective than usual GP care alone. Clinical rehabilitation and/or occupational intervention, and acupuncture were more cost-effective than usual GP care. One study investigated the cost-effectiveness of guideline-based GP care, and found that adding exercise and/or spinal manipulation was more cost-effective than guideline-based GP care alone. In conclusion, GP care alone did not appear to be the most cost-effective treatment option for low back pain. GPs can improve the cost-effectiveness of their treatment by referring their patients for additional services, such as advice and exercise, or by providing the services themselves
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