Neutron halos in heavy nuclei -- relativistic mean field approach

Assuming a~simple spherical relativistic mean field model of the nucleus, we estimate the width of the antiproton--neutron annihilation ($\Gamma_n$) and the width of antiproton--proton ($\Gamma_p$) annihilation, in an antiprotonic atom system. This allows us to determine the halo factor $f$, which is then discussed in the context of experimental data obtained in measurements recently done on LEAR utility at CERN. Another quantity which characterizes the deviation of the average nuclear densities ratio from the corresponding ratio of the homogeneous densities is introduced too. It was shown that it is also a good indicator of the neutron halo. The results are compared to experimental data as well as to the data of the simple liquid droplet model of the nuclear densities. The single particle structure of the nuclear density tail is discusssed also.Comment: revtex, 12 pages + 6 postscript figure

Low oxygen saturation and mortality in an adult cohort; the Tromsø Study

Published version, also available at http://dx.doi.org/10.1186/s12890-015-0003-5Background: Oxygen saturation has been shown in risk score models to predict mortality in emergency medicine. The aim of this study was to determine whether low oxygen saturation measured by a single-point measurement by pulse oximetry (SpO2) is associated with increased mortality in the general adult population. Methods: Pulse oximetry was performed in 5,152 participants in a cross-sectional survey in Tromsø, Norway, in 2001–2002 (“Tromsø 5”). Ten-year follow-up data for all-cause mortality and cause of death were obtained from the National Population and the Cause of Death Registries, respectively. Cause of death was grouped into four categories: cardiovascular disease, cancer except lung cancer, pulmonary disease, and others. SpO2 categories were assessed as predictors for all-cause mortality and death using Cox proportional-hazards regression models after correcting for age, sex, smoking history, body mass index (BMI), C-reactive protein level, self-reported diseases, respiratory symptoms, and spirometry results. Results: The mean age was 65.8 years, and 56% were women. During the follow-up, 1,046 (20.3%) participants died. The age- and sex-adjusted hazard ratios (HRs) (95% confidence intervals) for all-cause mortality were 1.99 (1.33–2.96) for SpO2 ≤ 92% and 1.36 (1.15–1.60) for SpO2 93–95%, compared with SpO2 ≥ 96%. In the multivariable Cox proportional-hazards regression models that included self-reported diseases, respiratory symptoms, smoking history, BMI, and CRP levels as the explanatory variables, SpO2 remained a significant predictor of all-cause mortality. However, after including forced expiratory volume in 1 s percent predicted (FEV1% predicted), this association was no longer significant. Mortality caused by pulmonary diseases was significantly associated with SpO2 even when FEV1% predicted was included in the model. Conclusions: Low oxygen saturation was independently associated with increased all-cause mortality and mortality caused by pulmonary diseases. When FEV1% predicted was included in the analysis, the strength of the association weakened but was still statistically significant for mortality caused by pulmonary diseases

Coulomb order in a storage ring

We verify theoretically that the anomalous longitudinal temperature reduction of strongly electron cooled heavy ions in the ESR at very low density is explained by the fact that there is no intrabeam scattering and that the particles by their Coulomb repulsion cannot pass each other any more. At the achievable momentum spreads Coulomb order is reached at particle distances of the order of centimeters. It is also shown that under the given experimental conditions in the proton NAP-M experiment of 1980 intrabeam heating counteracts Coulomb order

Stability of Crystalline Ion Beams

In this paper, the conditions for which three-dimensional crystalline ion beams were attained in the rf quadrupole storage ring PALLAS at a velocity of around 2800 m/s are presented. The stability of these crystalline beams when subjected to discontinuous cooling is discussed for beams of different linear density and thus of different crystal structure. The survival time seems to only weakly depend on the linear density, in contrast to the heating of the beam after melting