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The $^{64}\mathrm{Zn}$($t$,$^{3}\mathrm{He}$) reaction has been studied by using a secondary triton beam of 115 MeV/nucleon to extract the Gamow-Teller transition-strength distribution to $^{64}\mathrm{Cu}$. The results were compared with shell-model calculations with the $\mathit{pf}$-shell effective interactions KB3G and GXPF1A and with existing data from the $^{64}\mathrm{Zn}$($d$,$^{2}\mathrm{He}$) reaction. Whereas the experimental results exhibited good consistency, neither of the theoretical predictions managed to reproduce the data. The implications for electron-capture rates during late stellar evolution were investigated. The rates based on the theoretical strength distributions are lower by factors of 3.5--5 compared to the rates based on experimental strength distributions.

Experience NSCL; International audience; We report in this study the nuclear properties of proton-rich isotopes located along the rp-process path. The experiments have recently been performed at the National Superconducting Cyclotron Laboratory (NSCL) at Michigan State University. The level properties above the proton separation energy of the nuclei 30S, 36K and 37Ca were measured with precision of < 10 keV. This will allow a reduction in the determination of the astrophysical (p, ) reaction rate under rp-process conditions.

Gamow-Teller transitions from $^{24}\mathrm{Mg}$ to $^{24}\mathrm{Na}$ were studied via the ($t,{}^{3}\mathrm{He}$) reaction at $115A$ MeV using a secondary triton beam produced via fast fragmentation of $150A$ MeV $^{16}\mathrm{O}$ ions. Compared to previous ($t,{}^{3}\mathrm{He}$) experiments at this energy that employed a primary $\ensuremath{\alpha}$ beam, the secondary beam intensity is improved by about a factor of five. Despite the large emittance of the secondary beam, an excitation-energy resolution of $~200$ keV is achieved. A good correspondence is found between the extracted Gamow-Teller strength distribution and those available from other charge-exchange probes. Theoretical calculations using the newly developed USDA and USDB $\mathit{sd}$-shell model interactions reproduce the data well.

The $^{24}\mathrm{Mg}(^{3}\mathrm{He},t){}^{24}$Al reaction was studied at $E({}^{3}\mathrm{He})=420$ MeV. An energy resolution of 35 keV was achieved. Gamow-Teller strengths to discrete levels in $^{24}\mathrm{Al}$ were extracted by using a recently developed empirical relationship for the proportionality between Gamow-Teller strengths and differential cross sections at zero momentum transfer. Except for small discrepancies for a few weak excitations, good agreement with previous $^{24}\mathrm{Mg}$($p,n$) data and nuclear-structure calculations using the USDA/B interactions in the $\mathit{sd}$ shell-model space was found. The excitation energy of several levels in $^{24}\mathrm{Al}$ of significance for determination of the $^{23}\mathrm{Mg}$${(p,\ensuremath{\gamma})}^{24}$Al thermonuclear reaction rate were measured. Results are consistent with two of the three previous ($^{3}\mathrm{He}$,$t$) measurements, performed at much lower beam energies. However, a new state at ${E}_{x}({}^{24}\mathrm{Al})=2.605(10)$ MeV was found and is the third state above the proton separation energy.

Differential cross sections for transitions of known weak strength were measured with the (He-3, t) reaction at 420 MeV on targets of C-12, C-13, O-18, Mg-26, Ni-58, Ni-60, Zr-90, Sn-118, Sn-120, and Pb-208. Using these data, it is shown that the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in the distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions.

Differential cross sections for transitions of known weak strength were measured with the (3He,t) reaction at 420 MeV on targets of 12C, 13C, 18O, 26Mg, 58Ni, 60Ni, 90Zr, 118Sn, 120Sn and 208Pb. Using this data, it is shown the proportionalities between strengths and cross sections for this probe follow simple trends as a function of mass number. These trends can be used to confidently determine Gamow-Teller strength distributions in nuclei for which the proportionality cannot be calibrated via beta-decay strengths. Although theoretical calculations in distorted-wave Born approximation overestimate the data, they allow one to understand the main experimental features and to predict deviations from the simple trends observed in some of the transitions., 4 pages, 2 figures

The collective and single-particle structure of nuclei in the 132Sn region was recently studied by Coulomb excitation and heavy-ion induced transfer reactions using carbon, beryllium, and titanium targets. In particular, Coulomb excitation was used determine a complete set of electromagnetic moments for the first 2+ states and one-neutron transfer was used to probe the purity and evolution of single-neutron states. These recent experiments were conducted at the Holifield Radioactive Ion Beam Facility at ORNL using a Csl-HPGe detector array (BareBall- CLARION) to detect scattered particles and emitted gamma rays from the in-beam reactions. A Bragg-curve detector was used to measure the energy loss of the various beams through the targets and to measure the radioactive beam compositions. A sample of the Coulomb excitation results is presented here with an emphasis placed on 116Sn. In particular, the "safe Coulex" criterion for carbon targets will be analyzed and discussed.

It is shown via a study on a {sup 26}Mg target that the (t,{sup 3}He) reaction at 115 MeV/nucleon reaction is an accurate probe for extracting Gamow-Teller transition strengths. To do so, the data are complemented by results from the {sup 26}Mg({sup 3}He, t) reaction at 140 MeV/nucleon that allows for a comparison of T=2 analog states excited via the mirror reactions. Extracted Gamow-Teller strengths from {sup 26}Mg(t,{sup 3}He) and {sup 26}Mg({sup 3}He, t) are compared with those from {sup 26}Mg(d,{sup 2}He) and {sup 26}Mg(p,n) studies, respectively. A good correspondence is found, indicating probe independence of the strength extraction. Furthermore, we test shell-model calculations using the new USD-05B interaction in the sd-model space and show that it reproduces the experimental Gamow-Teller strength distributions well. In anticipation of further (t,{sup 3}He) experiments on medium-heavy nuclei aimed at determining weak-interaction rates of relevance for stellar evolution, a second goal of this work is to improve the understanding of the (t,{sup 3}He) and ({sup 3}He, t) reaction mechanisms at intermediate energies because detailed studies are scarce. The distorted-wave Born approximation is employed, taking into account the composite structures of the {sup 3}He and triton particles. The reaction model provides the means to explainmore » systematic uncertainties at the 10%-20% level in the extraction of Gamow-Teller strengths as being because of interference between Gamow-Teller {delta}L=0,{delta}S=1 and {delta}L=2,{delta}S=1 amplitudes that both contribute to transitions from 0{sup +} to 1{sup +} states.« less

The Ni-58 (t, He-3)Co-58 reaction at 112 MeV/nucleon was measured to identify strength associated with Gamow-Teller transitions in the T-z = +1 direction. The experiment is a test case for future similar studies. The main aim of such studies is to test theoretical models used to predict Gamow-Teller strength distributions that serve as input for supernovae evolution calculations. The results indicate that the (t, He-3) reaction is indeed a powerful tool to perform such tests.

We report on the first determination of the absolute B(E2;0+(1)-->2+(1)) excitation strength in the N=Z nucleus 72Kr. 72Kr is the heaviest N=Z nucleus for which this quantity has been measured and provides a benchmark in a region of the nuclear chart dominated by rapidly changing deformations and shapes mediated by the interplay of strongly oblate and prolate-driving orbitals. The deduced quadrupole deformation strength is in agreement with a variety of self-consistent models that predict an oblate shape for the ground state of 72Kr. Large-scale shell-model Monte Carlo calculations reproduce the experimental B(E2) value and link the result to the occupation of the deformation-driving g9/2 orbit.

The r-process is responsible for creating roughly half of the elements heavier than iron. It has recently become understood that the rates at which neutron capture reactions proceed at late times in the r-process may dramatically affect the final abundance pattern. However, direct measurements of neutron capture reaction rates on exotic nuclei are exceptionally difficult, necessitating the development of indirect approaches such as the surrogate technique. The (d,pγ) reaction at low energies was identified as a promising surrogate for the (n,γ) reaction, as both reactions share many characteristics. We report on a program to validate (d,pγ) as a surrogate for (n,γ) using 95Mo as a target. The experimental campaign includes direct measurements of the γ-ray intensities from the decay of excited states populated in the 95Mo(n,γ) and 95Mo(d,pγ) reactions.

Direct reaction techniques are powerful tools to study the single-particle nature of nuclei. Performing direct reactions on short-lived nuclei requires radioactive ion beams produced either via fragmentation or the Isotope Separation OnLine (ISOL) method. Some of the most interesting regions to study with direct reactions are close to the magic numbers where changes in shell structure can be tracked. These changes can impact the final abundances of explosive nucleosynthesis. The structure of the chain of tin isotopes is strongly influenced by the Z=50 proton shell closure, as well as the neutron shell closures lying in the neutron-rich, N=82, and neutron-deficient, N=50, regions. Here we present two examples of direct reactions on exotic tin isotopes. The first uses a one-neutron transfer reaction and a low-energy reaccelerated ISOL beam to study states in 131Sn from across the N=82 shell closure. The second example utilizes a one-neutron knockout reaction on fragmentation beams of neutron-deficient 106,108Sn. In both cases, measurements of gamma rays in coincidence with charged particles proved to be invaluable., 11 pages, 5 figures, Zakopane Conference on Nuclear Physics "Extremes of the Nuclear Landscape", Zakopane, Poland, August 31 - September 7, 2014

Rehabilitation of the anterior cruciate ligament absent or reconstructed knee is becoming a true artform. Accelerated, but controlled rehabilitation, is becoming more commonplace. Scientific-based data along with clinical experiences are the basis of the rehabilitation guidelines brought forth in this article. Anterior cruciate ligament strain and implications for exercise, continuous passive motion, proprioceptive exercise, and the role of knee bracing are all discussed in relation to the overall rehabilitation program.

— The Gyricon display consists of hemispherical black and white (bichromal) balls contained in individual liquid-filled cavities and disposed to orient in an electrical field. This bistable reflective light display currently has a diffuse reflectance of more than 18% and a contrast ratio of more than 6:1. The viewing angle approaches that of paper. A new method of fabricating the bichromal balls has enabled practical realization of large-area high-quality displays.

The requirements for practical electronic paper are discussed. It is shown that the Gyricon is a strong candidate for such electronic paper applications. The means for addressing Gyricon sheets using a stylus array and patterned conductive islands is discussed.

The requirements for practical electronic paper are discussed. It is is shown that the Gyricon is a strong candidate for such electronic paper applications. The means for addressing Gyricon sheets using a stylus array and patterned conductive islands are discussed.

(1) Available data on factors affecting male, nonhuman primate sexual arousal and seminal emission are presented. (2) The results of a twelve-month study on baboon seminal emissions are analyzed and related to the reproductive events of free-ranging conspecifics. (3) Evidence for a heightened sexual arousal state in male baboons as a result of mating test opportunities with estradiol benzoate primed ovariectomized females is discussed. (4) Sexual arousal increases as assessed by seminal emissions and peripheral testosterone levels resulted from exposure of noncontact variety to estrogen treated stimulus females. (5) Discussion of the presented results centers on factors critical to baboon sexual arousal.

Captive adult male chacma baboons (Papio ursinus) housed with natural lighting exposure and blood sampled at 3-hr intervals showed significant diurnal variations in serum testosterone concentrations. Low mean concentrations were found at 0800 hr approximately 1 hr after sunrise and mean concentrations were their highest at 2000 hr approximately 1 ¼ hr after sunset.

The menstrual cycle characteristics of 2 groups of adult female Chacma baboons were compared. Out of a group of 27 female baboons, 41% (11/27) failed to cycle during the 6 month study period but were all under the stresses of fairly severe experimental manipulation. Data on the menstrual cycles of the remaining 16 unmanipulated females was collected and carefully analysed. These 16 females were individually caged and denied social contact with other baboons. Their menstrual cycles were then contrasted to those of a group of 8 individually caged females which received 24 minute mating tests with vasectomized males on alternate days during their cycles. The females denied the social contact of the mating tests showed significantly longer cycles as a result of significantly lengthened periods up to the time of perineal detumescence.

Studying ({alpha},p) reactions of astrophysical interest with radioactive beams presents serious challenges because of the difficult nature of the target. We have developed a new approach for the measurement of ({alpha},p) reactions using heavy ion beams in inverse kinematics and have measured the {sup 4}He({sup 19}F,{sup 1}H){sup 22}Ne reaction as a demonstration. {sup 19}F beams were used at the Holifield Radioactive Ion Beam Facility (HRIBF) tandem accelerator in Oak Ridge National Laboratory (ORNL) to bombard a large scattering chamber filled with {sup 4}He gas. Recoiling protons from the reactions were detected by the large area annular silicon strip detector array (SIDAR). The {sup 19}F({alpha},p) and {sup 19}F({alpha},p') excitation functions were measured over the energy range of E{sub c.m.} {approx} 1-2.1 MeV, demonstrating the viability of the technique