Hindrance of Heavy-ion Fusion at Extreme Sub-Barrier Energies in Open-shell Colliding Systems

The excitation function for the fusion-evaporation reaction 64Ni+100Mo has been measured down to a cross-section of ~5 nb. Extensive coupled-channels calculations have been performed, which cannot reproduce the steep fall-off of the excitation function at extreme sub-barrier energies. Thus, this system exhibits a hindrance for fusion, a phenomenon that has been discovered only recently. In the S-factor representation introduced to quantify the hindrance, a maximum is observed at E_s=120.6 MeV, which corresponds to 90% of the reference energy E_s^ref, a value expected from systematics of closed-shell systems. A systematic analysis of Ni-induced fusion reactions leading to compound nuclei with mass A=100-200 is presented in order to explore a possible dependence of the fusion hindrance on nuclear structure.Comment: 10 pages, 9 figures, Submitted to Phys. Rev.

Clinical and Financial Impact of Readmissions Following Colorectal Resection: An Analysis of Predictors, Outcomes, and Cost

Background: Following passage of the Affordable Care Act, 30day readmissions have come under greater scrutiny, with penalties levied for higher than expected readmission rates. We examined risk factors for 30day readmission following colorectal resection and evaluated the financial impact of readmissions on the healthcare system. Methods: The University HealthSystem Consortium Clinical Database was queried for adults undergoing colorectal surgery for cancer, diverticular disease, inflammatory bowel disease, or benign tumors from 2008-2012. Predictors of 30day readmission were assessed with multivariable logistic regression. Additional endpoints included time to readmission, readmission diagnosis, readmission length of stay (LOS), and readmission cost. Results: A total of 70,484 patients met study inclusion criteria, 13.7% (9,632) of which were readmitted within 30 days of discharge. The strongest independent predictors of readmission were: LOS ≥4 days (OR 1.44; 95% CI 1.32-1.57), stoma (OR 1.54; 95% CI 1.46-1.51), and non-home discharge (OR 1.68; 95% CI 1.57-1.81). Of those readmitted, half occurred within 7 days, 13% required ICU care, 6% had a reoperation, and 2% died during the readmission stay. The median combined total direct hospital cost was over two times higher ($26,917 v.$13,817; p\u3c0.001) than non-readmitted patients. Compared with late readmissions, those readmitted within 7 days were more likely to have a reoperation (8% v. 4%, p\u3c0.001), be admitted to the ICU (14% vs. 12%, p\u3c0.001), and had a longer median readmission LOS (5d vs. 4d, p\u3c0.001). CONCLUSIONS: 30-day readmissions following colorectal resection occur frequently and incur a significant financial burden on the healthcare system. Highest-risk patients include those with longer LOS, stoma, and non-home discharge. Future studies aimed at targeted interventions may reduce readmissions and curb escalating healthcare costs

Influence of nuclear structure on sub-barrier hindrance in Ni+Ni fusion

Fusion-evaporation cross sections for $^{64}$Ni+$^{64}$Ni have been measured down to the 10 nb level. For fusion between two open-shell nuclei, this is the first observation of a maximum in the $S$-factor, which signals a strong sub-barrier hindrance. A comparison with the $^{58}$Ni+$^{58}$Ni, $^{58}$Ni+$^{60}$Ni, and $^{58}$Ni+$^{64}$Ni systems indicates a strong dependence of the energy where the hindrance occurs on the stiffness of the interacting nuclei.Comment: Submitted to Phys. Rev. Lett. 4 pages, 3 figure

Theoretical description of deformed proton emitters: nonadiabatic coupled-channel method

The newly developed nonadiabatic method based on the coupled-channel Schroedinger equation with Gamow states is used to study the phenomenon of proton radioactivity. The new method, adopting the weak coupling regime of the particle-plus-rotor model, allows for the inclusion of excitations in the daughter nucleus. This can lead to rather different predictions for lifetimes and branching ratios as compared to the standard adiabatic approximation corresponding to the strong coupling scheme. Calculations are performed for several experimentally seen, non-spherical nuclei beyond the proton dripline. By comparing theory and experiment, we are able to characterize the angular momentum content of the observed narrow resonance.Comment: 12 pages including 10 figure

Nuclear Reaction Studies with Radioactive {sup 18}F Beams at ATLAS

The contribution of the {sup 18}F(p,{gamma}) reaction to the production of {sup 19}Ne which is the crucial isotope for the breakout from the hot CNO cycle into the rp process, has been investigated in experiments with {sup 18}F beams. Measurements of the cross sections for the {sup 18}F(p,{alpha}){sup 15}O and the {sup 18}F(p,{gamma}){sup 19}Ne reactions indicate that the contribution from the (p,{gamma}) route to the formation of {sup 19}Ne is small

The Influence of {sup 18} F Induced Reactions in the Hot CNO Cycle

The contribution of the {sup 18}F(p,{gamma}) reaction to the production of {sup 19}Ne, which is an important isotope in connection with the breakout from the hot CNO cycle, has been investigated in experiments with {sup 18}F beams. Measurements of the cross sections for the {sup 18}F(p,{alpha}){sup 15}O and {sup 18}F(p,{gamma}){sup 19 }Ne reactions indicate that the contribution of the {sup 18}F(p, {gamma}) route to the formation or {sup 19}Ne is small