Proton Drip-Line Calculations and the Rp-process

One-proton and two-proton separation energies are calculated for proton-rich nuclei in the region $A=41-75$. The method is based on Skyrme Hartree-Fock calculations of Coulomb displacement energies of mirror nuclei in combination with the experimental masses of the neutron-rich nuclei. The implications for the proton drip line and the astrophysical rp-process are discussed. This is done within the framework of a detailed analysis of the sensitivity of rp process calculations in type I X-ray burst models on nuclear masses. We find that the remaining mass uncertainties, in particular for some nuclei with $N=Z$, still lead to large uncertainties in calculations of X-ray burst light curves. Further experimental or theoretical improvements of nuclear mass data are necessary before observed X-ray burst light curves can be used to obtain quantitative constraints on ignition conditions and neutron star properties. We identify a list of nuclei for which improved mass data would be most important.Comment: 20 pages, 9 figures, 2 table

Effects of diet and exercise on weight-related outcomes for breast cancer survivors and their adult daughters: an analysis of the DAMES trial

Purpose Few trials have aimed to promote diet and exercise behaviors in both cancer survivors and their family members and examine their associations with weight-related outcomes. We conducted a secondary analysis to examine associations between change in diet and exercise behaviors and weight-related outcomes for overweight breast cancer survivors and their overweight adult daughters in the Daughters And MothErS Against Breast Cancer (DAMES) randomized trial. Methods The DAMES trial assessed the impact of two iteratively tailored, mailed print diet and exercise interventions against standard brochures over a 12-month period. This analysis examined change in diet and exercise behaviors and weight-related variables from baseline to post-intervention for the 50 breast cancer survivors and their adult daughters randomized to the intervention arms. To reduce the potential for type II error in this pilot, p values <0.10 were considered statistically significant. Results For mothers, change in diet quality was uniquely related to change in BMI (β = −0.12, p = 0.082), weight (β = −0.12, p = 0.060), and waist circumference (β = −0.38, p = 0.001), whereas change in caloric intake was related to waist circumference (β = 0.21, p = 0.002). For daughters, change in caloric intake was related to change in waist circumference (β = 0.12, p = 0.055). However, change in diet quality was not associated with weight-related outcomes in daughters. Additionally, change in exercise was not associated with weight-related outcomes in mothers or daughters. Conclusions Findings support mail-based and other tailored interventions for weight loss in this population, with an emphasis on diet quality for breast cancer survivors and caloric intake for their adult daughters

On the discovery of doubly-magic 48^{48}Ni

The paper reports on the first observation of doubly-magic Nickel-48 in an experimental at the SISSI/LISE3 facility of GANIL. Four Nickel-48 isotopes were identified. In addition, roughly 100 Nickel-49, 50 Iron-45, and 290 Chromium-42 isotopes were observed. This opens the possibility to search for two-proton emission from these nuclei.Comment: 4 pages, 3 figures, accepted for publication in Phys. Rev. Let

Improving the performance of bright quantum dot single photon sources using amplitude modulation

Single epitaxially-grown semiconductor quantum dots have great potential as single photon sources for photonic quantum technologies, though in practice devices often exhibit non-ideal behavior. Here, we demonstrate that amplitude modulation can improve the performance of quantum-dot-based sources. Starting with a bright source consisting of a single quantum dot in a fiber-coupled microdisk cavity, we use synchronized amplitude modulation to temporally filter the emitted light. We observe that the single photon purity, temporal overlap between successive emission events, and indistinguishability can be greatly improved with this technique. As this method can be applied to any triggered single photon source, independent of geometry and after device fabrication, it is a flexible approach to improve the performance of solid-state systems, which often suffer from excess dephasing and multi-photon background emission

βdecays of \u3csup\u3e92\u3c/sup\u3eRb, \u3csup\u3e96gs\u3c/sup\u3eY, and \u3csup\u3e142\u3c/sup\u3eCs measured with the modular total absorption spectrometer and the influence of multiplicity on total absorption spectrometry measurements

Total absorption spectroscopy is a technique that helps obtain reliable β-feeding patterns of complex decays important for nuclear structure and astrophysics modeling as well as decay heat analysis in nuclear reactors. The need for improved measurements of β-feeding patterns from fission decay products has come to the forefront of experiments that use nuclear reactors as a source of antineutrinos. Here we present more detailed results, in particular the β-decay measurements of 96gsY, and demonstrate the impact of the β-delayed γ multiplicity on the overall efficiency of Modular Total Absorption Spectrometer used at Oak Ridge National Laboratory to study the decays of fission products abundant during a nuclear fuel cycle

Decays of the Three Top Contributors to the Reactor ν - e High-Energy Spectrum, Rb 92, y 96gs, and Cs 142, Studied with Total Absorption Spectroscopy

We report total absorption spectroscopy measurements of Rb92, Y96gs, and Cs142 β decays, which are the most important contributors to the high energy ν-e spectral shape in nuclear reactors. These three β decays contribute 43% of the ν-e flux near 5.5 MeV emitted by nuclear reactors. This ν-e energy is particularly interesting due to spectral features recently observed in several experiments including the Daya Bay, Double Chooz, and RENO Collaborations. Measurements were conducted at Oak Ridge National Laboratory by means of proton-induced fission of U238 with on-line mass separation of fission fragments and the Modular Total Absorption Spectrometer. We observe a β-decay pattern that is similar to recent measurements of Rb92, with a ground-state to ground-state β feeding of 91(3)%. We verify the Y96gs ground-state to ground-state β feeding of 95.5(20)%. Our measurements substantially modify the β-decay feedings of Cs142, reducing the β feeding to Ba142 states below 2 MeV by 32% when compared with the latest evaluations. Our results increase the discrepancy between the observed and the expected reactor ν-e flux between 5 and 7 MeV, the maximum excess increases from ∼10% to ∼12%

Understanding the Sequence-Dependence of DNA Groove Dimensions: Implications for DNA Interactions

BACKGROUND: The B-DNA major and minor groove dimensions are crucial for DNA-protein interactions. It has long been thought that the groove dimensions depend on the DNA sequence, however this relationship has remained elusive. Here, our aim is to elucidate how the DNA sequence intrinsically shapes the grooves. METHODOLOGY/PRINCIPAL FINDINGS: The present study is based on the analysis of datasets of free and protein-bound DNA crystal structures, and from a compilation of NMR (31)P chemical shifts measured on free DNA in solution on a broad range of representative sequences. The (31)P chemical shifts can be interpreted in terms of the BI↔BII backbone conformations and dynamics. The grooves width and depth of free and protein-bound DNA are found to be clearly related to the BI/BII backbone conformational states. The DNA propensity to undergo BI↔BII backbone transitions is highly sequence-dependent and can be quantified at the dinucleotide level. This dual relationship, between DNA sequence and backbone behavior on one hand, and backbone behavior and groove dimensions on the other hand, allows to decipher the link between DNA sequence and groove dimensions. It also firmly establishes that proteins take advantage of the intrinsic DNA groove properties. CONCLUSIONS/SIGNIFICANCE: The study provides a general framework explaining how the DNA sequence shapes the groove dimensions in free and protein-bound DNA, with far-reaching implications for DNA-protein indirect readout in both specific and non specific interactions

New transitions and levels for Tb 163 obtained from β -decay studies

Transitions in Tb163 following β decay of Gd163 were obtained as part of investigations of γ rays emitted following Eu163β decay to Gd163. Detailed analysis of the low-energy structure of Tb163 has been carried out with these data to expand previous β-decay studies and reactions studies of levels in Tb163. Data were collected at the LeRIBSS station of the Holifield Radioactive Ion Beam Facility at Oak Ridge National Laboratory with an array of four Clover HPGe detectors for γ rays and two plastic scintillators for β detection. The γ rays were identified as belonging to Gd163 and Tb163 via mass selection and γ-γ-β, γ-γ, or γ-x-ray coincidence. In total, 38 new γ-ray transitions were observed in Tb163 from 15 newly identified levels and 12 previously identified levels. Potential energy surface calculations were performed which support a rigid prolate deformation. Previously identified unplaced transitions in Tb163 have been placed within the level scheme of Tb163 and additional states and transitions have been identified