Measurement of the

The cross section of the ^{13}C(α,n)^{16}O reaction is needed for nuclear astrophysics and applications to a precision of 10% or better, yet inconsistencies among 50 years of experimental studies currently lead to an uncertainty of ≈15%. Using a state-of-the-art neutron detection array, we have performed a high resolution differential cross section study covering a broad energy range. These measurements result in a dramatic improvement in the extrapolation of the cross section to stellar energies potentially reducing the uncertainty to ≈5% and resolving long standing discrepancies in higher energy data.

Measurement of Low-Energy Resonance Strengths in the

The ^{18}O(α,γ)^{22}Ne reaction is an essential part of a reaction chain that produces the ^{22}Ne(α,n)^{25}Mg neutron source for both the weak and main components of the slow neutron-capture process. At temperatures of stellar helium burning, the astrophysically relevant resonances in the ^{18}O(α,γ)^{22}Ne reaction that dominate the reaction rate occur at α particle energies E_{lab} of 472 and 569 keV. However, previous experiments have shown the strengths of these two resonances to be very weak, and only upper limits or partial resonance strengths could be obtained. This Letter reports the first direct measurement of the total resonance strength for the 472- and 569-keV resonances, 0.26±0.05 and 0.63±0.30 µeV, respectively. New resonance strengths for the resonances at α particle energies of 662.1, 749.9, and 767.6 keV are also provided. These results were achieved in an experiment optimized for background suppression and detection efficiency. The experiment was performed at the Sanford Underground Research Facility, in the 4850-foot underground cavity dedicated to the Compact Accelerator System for Performing Astrophysical Research. The experimental end station used the γ-summing High EffiCiency TOtal absorption spectrometeR. Compared to previous works, the results decrease the stellar reaction rate by as much as ≈46_{-11}^{+6}% in the relevant temperature range of stellar helium burning.

New

Precise antineutrino measurements are very sensitive to proper background characterization. We present an improved measurement of the ^{13}C(α,n)^{16}O reaction cross section which constitutes significant background for large ν[over ¯] detectors. We greatly improve the precision and accuracy by utilizing a setup that is sensitive to the neutron energies while making measurements of the excited state transitions via secondary γ-ray detection. Our results shows a 54% reduction in the background contributions from the ^{16}O(3^{-},6.13 MeV) state used in the KamLAND analysis.

First Direct Measurement of (12)C((12)C,n)(23)Mg at Stellar Energies.

Neutrons produced by the carbon fusion reaction (12)C((12)C,n)(23)Mg play an important role in stellar nucleosynthesis. However, past studies have shown large discrepancies between experimental data and theory, leading to an uncertain cross section extrapolation at astrophysical energies. We present the first direct measurement that extends deep into the astrophysical energy range along with a new and improved extrapolation technique based on experimental data from the mirror reaction (12)C((12)C,p)(23)Na. The new reaction rate has been determined with a well-defined uncertainty that exceeds the precision required by astrophysics models. Using our constrained rate, we find that (12)C((12)C,n)(23)Mg is crucial to the production of Na and Al in pop-III pair instability supernovae. It also plays a nonnegligible role in the production of weak s-process elements, as well as in the production of the important galactic γ-ray emitter (60)Fe.

Elastic alpha-12C scattering and the 12C(alpha,gamma)16O E2 S factor.

Angular distributions of 12C(alpha,alpha)12C have been measured for E(alpha) = 2.6-8.2 MeV, at angles from 24 to 166, yielding 12 864 data points. R-matrix analysis of the ratios of elastic scattering yields a reduced width amplitude of gamma12 = 0.47 +/- 0.06 MeV(1/2) for the Ex = 6.917 MeV (2+) state in 16O(a = 5.5 fm). The dependence of the chi2 surface on the interaction radius a has been investigated and a deep minimum is found at a = 5.42(+0.16)(-0.27) fm. Using this value of gamma12, radiative alpha capture and 16N beta-delayed alpha-decay data, the S factor is calculated at E(c.m.) = 300 keV to be S(E2)(300) = 53(+13)(-18) keV b for destructive interference between the subthreshold resonance tail and the ground state E2 direct capture.

[Late results of breast augmentation]. / Spätergebnisse der Mammaaugmentation.

Late results of augmentation mammaplasty with dermis fat transplants and implants are presented and discussed separately. With correct handling and strict indication a mammary implant heals in without complications and with good results. The problem of capsular fibrosis is discussed. Prerequisites for augmentation mammoplasty are detailed information about and strict selection of candidates.

[Results of McKissock reduction mammoplasty]. / Ergebnisse der Mammareduktionsplastik nach McKissock.

Reducing mammoplasty is medically justified a surgical intervention to handle certain indications. Results obtained from this approach are discussed in comparison to other methods, primarily the Strömbeck technique, with reference being made to 217 patients of whom the majority had undergone McKissock operations. Ninety per cent of these patients were absolutely satisfied, and only eight per cent had restrictions. However, broadened or hypertrophic scars were recorded from 21 per cent in objective assessments by follow-up examiners. The method according to McKissock can be recommended for cases of mammary ptosis and macromastia. A two-stage approach, according to Joseph, should be taken to cases in which more than 1,400 g of tissue are removed from one side. No increased incidence of mammary tumours was recordable in the wake of reducing mammoplasty.

[Problem of oral surgical interventions during pregnancy, menstruation and under the intake of hormonal contraceptives]. / Zur Problematik stomatologisch-chirurgischer Eingriffe während der Schwangerschaft, Menstruation under unter der Einnahme hormonaler Kontrazeptiva.

Pregnancy, menstruation and hormonal contraceptives are no contraindications for necessary oral surgical procedures. If the pregnancy takes a normal course, surgical interventions with absolute indication are possible at any time. Surgical interventions with relative indication should be performed during the second trimester of pregnancy. The dental treatment of pregnant women should be terminated, as far as possible, by the 7th or 8th month of pregnancy. Metabolic imbalances, static loading and gingival changes deserve special attention.

PIP: Factors involved in performing oral surgery in conjunction with menstruation, pregnancy, and oral contraceptive (o.c.) use are presented. There are very small changes in blood coagulation factors during menstruation, with a longer premenstrual coagulation time. Only necessary major operations should be performed immediately before and during menstruation; extractions and abscess incisions can be performed at any time. Such small operations can also be performed without regard to o.c. use. Serious operations should be performed after the first spontaneous menstruation following discontinuation of o.c. use, due to increased risk of thromboembolism. In cases of emergency operations during o.c. use, a prophylactic against thromboembolic complications should be administered. Most necessary oral surgery can be performed during pregnancy. Where possible, oral surgery should be performed during the second trimester of pregnancy to avoid the possibility of spontaneous abortion in the first trimester and possible metabolic complications in the third trimester. Any operation on a women with eclampsia should be performed in conjunction with a birth attendant. A sitting position is preferred for performing oral surgery on pregnant patients to avoid the possibility of vena cava compression syndrome. An increased tendency of bleeding has not been established among pregnant surgical patients.