Ground-state proton decay of 69Br and implications for the 68Se astrophysical rapid proton-capture process waiting point

We report on the first direct measurement of the proton separation energy for the proton-unbound nucleus (69)Br. Bypassing the (68)Se waiting point in the rp process is directly related to the 2p-capture rate through (69)Br, which depends exponentially on the proton separation energy. We find a proton separation energy for (69)Br of Sp((69)Br )= -785(-40)(+34) keV; this is less bound compared to previous predictions which have relied on uncertain theoretical calculations. The influence of the extracted proton separation energy on the rp process occurring in type I x-ray bursts is examined within the context of a one-zone burst model.

Neutron-proton asymmetry dependence of spectroscopic factors in ar isotopes

Spectroscopic factors have been extracted for proton-rich 34Ar and neutron-rich 46Ar using the (p, d) neutron transfer reaction. The experimental results show little reduction of the ground state neutron spectroscopic factor of the proton-rich nucleus 34Ar compared to that of 46Ar. The results suggest that correlations, which generally reduce such spectroscopic factors, do not depend strongly on the neutron-proton asymmetry of the nucleus in this isotopic region as was reported in knockout reactions. The present results are consistent with results from systematic studies of transfer reactions but inconsistent with the trends observed in knockout reaction measurements.

Large beta-delayed neutron emission probabilities in the 78Ni region

The beta-delayed neutron branching ratios (P{betan}) for nuclei near doubly magic 78Ni have been directly measured using a new method combining high-resolution mass separation, reacceleration, and digital beta-gamma spectroscopy of 238U fission products. The P{betan} values for the very neutron-rich isotopes ;{76-78}Cu and 83Ga were found to be much higher than previously reported and predicted. Revised calculations of the betan process, accounting for new mass measurements and an inversion of the pi2p{3/2} and pi1f{5/2} orbitals, are in better agreement with these new experimental results.

Enhanced fusion-evaporation cross sections in neutron-rich 132Sn on 64Ni

Evaporation residue cross sections have been measured with neutron-rich radioactive 132Sn beams on 64Ni in the vicinity of the Coulomb barrier. The average beam intensity was 2 x 10(4) particles per second and the smallest cross section measured was less than 5 mb. Large sub-barrier fusion enhancement was observed. Coupled-channel calculations taking into account inelastic excitation significantly underpredict the measured cross sections below the barrier. The presence of several neutron transfer channels with large positive Q values suggests that multinucleon transfer may play an important role in enhancing the fusion of 132Sn and 64Ni.

Trapeziometacarpal joint osteoarthritis and carpal tunnel syndrome: a new surgical approach for concomitant treatment

A new approach for the concomitant surgical treatment of trapeziometacarpal joint osteoarthritis and carpal tunnel syndrome through the same incision is described. The technique was used in 25 patients (20 women, five men; mean age, 56 years). At a mean follow-up of 27 months, there was complete disappearance of the symptoms of carpal tunnel syndrome in 20 of the 25 patients, incomplete but substantial relief in four patients, and no improvement in one patient. One patient had scar tenderness and another had a superficial wound infection. The surgical technique is simple, safe and cost-effective as it avoids separate operations for both pathologies. The procedure is not suitable for severe carpal tunnel syndrome or when direct visualization of the median nerve and the carpal tunnel is necessary.

Nuclear fusion in collapsing bubbles-is it there? An attempt to repeat the observation of nuclear emissions from sonoluminescence

We have repeated the experiment of Taleyarkhan et al. [Science 295, 1868 (2002)]] in an attempt to detect the emission of neutrons from d-d fusion during bubble collapse in deuterated acetone. Using the same cavitation apparatus, a more sophisticated data acquisition system, and a larger scintillator detector, we find no evidence for 2.5-MeV neutron emission correlated with sonoluminescence form collapsing bubbles. Any neutron emission that might occur is at least 4 orders of magnitude too small to explain the tritium production reported in Taleyarkhan et al. as being due to d-d fusion. We show that proper allowance for random coincidence rates in such experiments requires the simultaneous measurement of the count rates in the individual detectors.

Coulomb excitation of radioactive 132,134,136Te beams and the low B(E2) of 136Te

The B(E2;0(+)-->2+) values for the first 2+ excited states of neutron-rich 132,134,136Te have been measured using Coulomb excitation of radioactive ion beams. The B(E2) values obtained for 132,134Te are in excellent agreement with expectations based on the systematics of heavy stable Te isotopes, while that for 136Te is unexpectedly small. These results are discussed in terms of proton-neutron configuration mixing and shell-model calculations using realistic effective interactions.

Decay of a Resonance in 18Ne by the Simultaneous Emission of Two Protons

Radioactive ion beams of 17F were used to study several resonance states in 18Ne. Clear evidence for simultaneous two-proton emission from the 6.15 MeV state (Jpi = 1(-)) in 18Ne has been observed with the reaction 17F+1H. Because of limited angular coverage, the data did not differentiate between the two possible mechanisms of simultaneous decay, diproton (2He) emission or direct three-body decay. The two-proton partial width was found to be 21+/-3 eV assuming 2He emission and 57+/-6 eV assuming three-body decay. The total width of the 1(-) state was measured to be 50+/-5 keV. Several additional resonances that decay by single proton emission were also studied.