A Cautionary Tale: The Coulomb Modified ANC for the 1/22+\mathbf{1/2^+_2} State in 17^\mathbf{17}O

We discuss the impact of the uncertainty ($\pm 8$ keV) in the excitation energy of the astrophysically important 6.356 MeV $1/2^+_2$ state of $^{17}$O on the precision with which the Coulomb reduced ANC ($\widetilde{C}$) for the \left<^{17}\mathrm{O}(1/2^+_2) \mid \protect{^{13}\mathrm{C}} + \alpha \right> overlap can be extracted from direct reaction data. We find a linear dependence of $\widetilde{C}^2$ on the binding energy, the value extracted varying by a factor of 4 over the range $E_{\mathrm{ex}} = 6.356$ -- $6.348$ MeV. This represents an intrinsic limit on the precision with which $\widetilde{C}^2$ can be determined which cannot be improved unless or until the uncertainty in $E_{\mathrm{ex}}$ is reduced

Strong coupling effects in near-barrier heavy-ion elastic scattering

Accurate elastic scattering angular distribution data measured at bombarding energies just above the Coulomb barrier have shapes that can markedly differ from or be the same as the expected classical Fresnel scattering pattern depending on the structure of the projectile, the target or both. Examples are given such as 18O + 184W and 16O + 148,152Sm where the expected rise above Rutherford scattering due to Coulomb-nuclear interference is damped by coupling to the target excited states, and the extreme case of 11Li scattering, where coupling to the 9Li + n + n continuum leads to an elastic scattering shape that cannot be reproduced by any standard optical model parameter set. The recent availability of high quality 6He, 11Li and 11Be data provides further examples of the influence that coupling effects can have on elastic scattering. Conditions for strong projectile-target coupling effects are presented with special emphasis on the importance of the beam-target charge combination being large enough to bring about the strong coupling effects. Several measurements are proposed that can lead to further understanding of strong coupling effects by both inelastic excitation and nucleon transfer on near-barrier elastic scattering. A final note on the anomalous nature of 8B elastic scattering is presented as it possesses a more or less normal Fresnel scattering shape whereas one would a priori not expect this due to the very low breakup threshold of 8B. The special nature of 11Li is presented as it is predicted that no matter how far above the Coulomb barrier the elastic scattering is measured, its shape will not appear as Fresnel like whereas the elastic scattering of all other loosely bound nuclei studied to date should eventually do so as the incident energy is increased, making both 8B and 11Li truly "exotic".Comment: Review articl

Tunneling spectroscopy for probing orbital anisotropy in iron pnictides

Using realistic multi-orbital tight-binding Hamiltonians and the T-matrix formalism, we explore the effects of a non-magnetic impurity on the local density of states in Fe-based compounds. We show that scanning tunneling spectroscopy (STS) has very specific anisotropic signatures that track the evolution of orbital splitting (OS) and antiferromagnetic gaps. Both anisotropies exhibit two patterns that split in energy with decreasing temperature, but for OS these two patterns map onto each other under 90 degree rotation. STS experiments that observe these signatures should expose the underlying magnetic and orbital order as a function of temperature across various phase transitions.Comment: 12 pages, 9 figures, replacement with minor changes suggested by referee

Integration ethologischer und funktioneller Merkmale in Zuchtprogramme für die Sau von morgen

Das Projekt „FreeSow“ hatte zum Ziel, Sauen hinsichtlich ihrer Eignung für freiere Abferkelsysteme und alternative Haltungsverfahren zu charakterisieren und diese Eigenschaften in die zukünftige Zuchtplanung zu integrieren, um einen wichtigen Beitrag zur nachhaltigen Tierzucht zu leisten. Da Systeme ohne Fixierung besondere Herausforderungen mit sich bringen, wird von einer in ihnen gehaltenen Sau erwartet, dass sie sowohl eine gute Mütterlichkeit gegenüber ihren Ferkeln aufweist als auch mögliche Interaktionen mit dem Menschen toleriert. Daher wurden im Projekt verschiedene Verhaltenstests zur Beschreibung des Verhaltens der Sauen entwickelt und angewandt. Für die praktische Datenerfassung über zwei Jahre standen der Basiszuchtbetrieb Garlitz (BHZP) mit 80 Bewegungsbuchten für detaillierte Untersuchungen und die ökologische Sauenhaltung des LBZ-Echem (LWK) für die Validierung unter ökologischen Bedingungen zur Verfügung. Umfangreiche Datenerhebungen und -analysen zur Tiergesundheit und zum Wohlbefindens bildeten einen weiteren Schwerpunkt. Alle im Rahmen des Projektes entwickelten Verhaltenstests zur Toleranz gegenüber menschlichen Interaktionen erwiesen sich als geeignet, um das Verhalten der Sauen in praxi zu charakterisieren. Die geschätzten Heritabilitäten für die Merkmale, die sich mittels Test ergaben und Verhalten der Sauen gegenüber Menschen charakterisierten, lagen im Bereich von h² = 0,131 bis h² = 1.87. Diese Erblichkeitsgrade lassen eine erfolgreiche züchterische Bearbeitung zu. Zudem fanden sich bei Genom-weiten Assoziationsstudien erste Hinweise auf vielversprechende SNPs. Für die Nutzung in einem Sauenplaner wurden neue Merkmale des Tierverhaltens entwickelt und integriert, so dass eine einfache Dokumentationsmöglichkeit für den Sauenhalter geschaffen worden ist. Bereits während der Projektlaufzeit wurde die Selektion gegen unerwünschte Verhaltensweisen von Sauen in Abferkelsystemen mit größerer Bewegungsmöglichkeit umgesetzt

DWBA analysis of the 13C(6Li,d)17O reaction at 10 MeV/nucleon and its astrophysical implications

The value of the alpha spectroscopic factor (S_alpha) of the 6.356 MeV 1/2+ state of 17O is believed to have significant astrophysical implications due to the importance of the 13C(alpha,n)16O reaction as a possible source of neutron production for the s process. To further study this effect, an accurate measurement of the 13C(6Li,d)17O reaction at E_lab = 60 MeV has been performed recently by Kubono et al., who found a new value for the spectroscopic factor of the 6.356 MeV 1/2+ state of 17O based on a distorted wave Born approximation (DWBA) analysis of these data. This new value, S_alpha approximately = 0.011, is surprisingly much smaller than those used previously in astrophysical calculations (S_alpha approximately = 0.3-0.7) and thus poses a serious question as to the role of the 13C(alpha,n)16O reaction as a source of neutron production. In this work we perform a detailed analysis of the same 13C(6Li,d)17O data within the DWBA as well as the coupled reaction channel (CRC) formalism. Our analysis yields an S_alpha value of over an order of magnitude larger than that of Kubono et al. for the 6.356 MeV 1/2+ state of 17O.Comment: 17 pages, 4 figures, minor changes, accepted by Nuclear Physics

Campylobacter spp., Enterococcus spp., Escherichia coli, Salmonella spp., Yersinia spp., and Cryptosporidium oocysts in semi-domesticated reindeer (Rangifer tarandus tarandus) in Northern Finland and Norway

The specific aim of this study was to assess the faecal shedding of zoonotic enteropathogens by semi-domesticated reindeer (Rangifer tarandus tarandus) to deduce the potential risk to human health through modern reindeer herding. In total, 2,243 faecal samples of reindeer from northern regions of Finland and Norway were examined for potentially enteropathogenic bacteria (Campylobacter species, Enterococcus species, Escherichia coli, Salmonella species and Yersinia species) and parasites (Cryptosporidium species) in accordance with standard procedures. Escherichia coli were isolated in 94.7%, Enterococcus species in 92.9%, Yersinia species in 4.8% of the samples and Campylobacter species in one sample only (0.04%). Analysis for virulence factors in E. coli and Yersinia species revealed no pathogenic strains. Neither Salmonella species nor Cryptosporidium oocysts were detected. The public health risk due to reindeer husbandry concerning zoonotic diseases included in this study has to be considered as very low at present but a putative epidemiological threat may arise when herding conditions are changed with respect to intensification and crowding

Important Influence of Entrance Channel Reorientation Coupling on Proton Stripping

While it is well established that the ground state reorientation coupling can have a significant influence on the elastic scattering of deformed nuclei, the effect of such couplings on transfer channels has been much less well investigated. In this letter we demonstrate that the 208Pb(7Li,6He)209Bi proton stripping reaction at an incident energy of 52 MeV can be well described by the inclusion of the 7Li ground state reorientation coupling within the coupled channels Born approximation formalism. Full finite-range distorted wave Born approximation calculations were previously found to be unable to describe these data. Addition of coupling to the 0.478-MeV 1/2- excited state of 7Li, together with the associated two-step transfer path, has little or no influence on the shape of the angular distributions (except that for stripping leading to the 1.61-MeV 13/2+ level of 209Bi which is significantly improved) but does affect appreciably the values of the 209Bi -> 208Pb + p spectroscopic factors. Implications for experiments with weakly-bound light radioactive beams are discussed

Influence of single-neutron stripping on near-barrier ⁶He+²⁰⁸Pb and ⁸He+²⁰⁸Pb elastic scattering

The influence of single-neutron stripping on the near-barrier elastic scattering angular distributions for the 6,8He+208Pb systems is investigated through coupled reaction channels (CRC) calculations fitting recently published data to explore the differences in the absorptive potential found in the scattering of these two neutron-rich nuclei. The inclusion of the coupling reduces the elastic cross section in the Coulomb-nuclear interference region for 8He scattering, whereas for 6He its major impact is on the large-angle elastic scattering. The real and imaginary dynamic polarization potentials are obtained by inverting the CRC elastic scattering S-matrix elements. These show that the main absorptive features occur between 11 and 12 fm for both projectiles, while the attractive features are separated by about 1 fm, with their main structures occurring at 10.5 fm for 6He and 11.5 fm for 8He