44 research outputs found
Nuclear excitation by electron capture followed by fast x-ray emission
The resonance strength of the two-step process of nuclear excitation by
electron capture followed by decay of the nucleus can be significantly
increased in highly charged ions if the resonant capture proceeds via an
excited electronic state with subsequent fast x-ray emission. For fully ionized
and , the {x-ray} decay
stabilizes the system against internal conversion of the captured electron,
with an increase of both nuclear lifetimes and resonance strengths of up to two
orders of magnitude compared with the case when occupied atomic orbitals
prevent the x-ray de-excitation. Applications of this effect to the measurement
of the not yet experimentally observed nuclear excitation by electron capture
and to dense astrophysical plasmas are discussed.Comment: 12 pages, 1 figure, 2 table
Deciphering myeloid-derived suppressor cells: isolation and markers in humans, mice and non-human primates
International audienceIn cancer, infection and inflammation, the immune system's function can be dysregulated. Instead of fighting disease, immune cells may increase pathology and suppress host-protective immune responses. Myeloid cells show high plasticity and adapt to changing conditions and pathological challenges. Despite their relevance in disease pathophysiology, the identity, heterogeneity and biology of myeloid cells is still poorly understood. We will focus on phenotypical and functional markers of one of the key myeloid regulatory subtypes, the myeloid derived suppressor cells (MDSC), in humans, mice and non-human primates. Technical issues regarding the isolation of the cells from tissues and blood, timing and sample handling of MDSC will be detailed. Localization of MDSC in a tissue context is of crucial importance and immunohistochemistry approaches for this purpose are discussed. A minimal antibody panel for MDSC research is provided as part of the Mye-EUNITER COST action. Strategies for the identification of additional markers applying state of the art technologies such as mass cytometry will be highlighted. Such marker sets can be used to study MDSC phenotypes across tissues, diseases as well as species and will be crucial to accelerate MDSC research in health and disease
First Measurement of the Ru(p,)Rh Cross Section for the p-Process with a Storage Ring
This work presents a direct measurement of the Ru()Rh cross section via a novel technique using a storage ring,
which opens opportunities for reaction measurements on unstable nuclei. A
proof-of-principle experiment was performed at the storage ring ESR at GSI in
Darmstadt, where circulating Ru ions interacted repeatedly with a
hydrogen target. The Ru()Rh cross section between 9
and 11 MeV has been determined using two independent normalization methods. As
key ingredients in Hauser-Feshbach calculations, the -ray strength
function as well as the level density model can be pinned down with the
measured () cross section. Furthermore, the proton optical potential
can be optimized after the uncertainties from the -ray strength
function and the level density have been removed. As a result, a constrained
Ru()Rh reaction rate over a wide temperature range is
recommended for -process network calculations.Comment: 10 pages, 7 figs, Accepted for publication at PR
Measurements of proton-induced reactions on ruthenium-96 in the ESR at GSI
8th International Conference on Nuclear Physics at Storage Rings Stori11, October 9-14, 2011 Laboratori Nazionale di Frascati, Italy.
Storage rings offer the possibility of measuring proton- and alpha-induced reactions in inverse kinematics. The combination of this approachwith a radioactive beamfacility allows, in principle, the determination of the respective cross sections for radioactive isotopes. Such data are highly desired for a better understanding of astrophysical nucleosynthesis processes like the p-process. A pioneering experiment has been performed at the Experimental Storage Ring (ESR) at GSI using a stable 96Ru beam at 9-11 AMeV and a hydrogen target. Monte-Carlo simulations of the experiment were made using the Geant4 code. In these simulations, the experimental setup is described in detail and all reaction channels can be investigated. Based on the Geant4 simulations, a prediction of the shape of different spectral components can be performed. A comparison of simulated predictions with the experimental results shows a good agreement and allows the extraction of the cross section
Isotope Shift in the Dielectronic Recombination of Three-electron \u3csup\u3eA\u3c/sup\u3eNdâ”â·âș
Isotope shifts in dielectronic recombination spectra were studied for Li-like ANd57+ ions with A = 142 and A = 150. From the displacement of resonance positions energy shifts ÎŽE142 150(2s-2p1/2) = 40.2(3)(6) meV [(stat)(sys)] and ÎŽE142 150(2s - 2p3/2) = 42.3(12)(20)meV of 2s - 2pj transitions were deduced. An evaluation of these values within a full QED treatment yields a change in the mean-square charge radius of 142 150ÎŽâš r2â© = -1.36(1)(3) fm2. The approach is conceptually new and combines the advantage of a simple atomic structure with high sensitivity to nuclear size
The impact of society on management control systems
© 2017 Elsevier Ltd The aim of this study is to investigate whether certain configurations of management controls dominate in certain societies (socio-cultural contexts) and whether the effectiveness of a given archetype of management control systems (MCSs) varies depending on the socio-cultural settingâthe societyâin which it operates. The study focuses on three socio-cultural groups and the corresponding institutional contexts (an Anglo-Saxon group, a Central European group, and a Northern European group) and three MCS archetypes (delegated bureaucratic control, delegated output control, and programmable output control). We use unique data from a cross-national, interview-based survey encompassing 610 strategic business units from nine countries (seven European countries plus Canada and Australia). The idea that firms tend to adapt MCSs to the socio-cultural context does not gain empirical support in this study. No significant differences in the distribution of MCSs between the three socio-cultural groups are noted. However, we do find that programmable output control has a more positive impact on effectiveness in Anglo-Saxon cultures, while delegated output control has a more positive impact on effectiveness in Northern Europe. Taken together these findings indicate that distinct differences between societies make a particular MCS design more appropriate in a given society, but where such differences are not dramatic (as in the present case), multiple MCS designs can be found in the same society
Storage-ring experiments on dielectronic recombination at the interface of atomic and nuclear physics
Novel causative variants in patients with achromatopsia
Purpose: To report five novel genetic variants in seven unrelated consanguineous families with achromatopsia (ACHM). Methods: Patients were examined with multimodal retinal imaging and full-field electroretinography (ffERG). Genetic testing was conducted using next-generation sequencing (NGS). Results: Three novel homozygous variants were detected in CNGA3: a missense c.967G > C (p.Ala323Pro) variant was detected in exon 8 (one patient), a splice site variant c.101 + 1G > A in intron 2 (three patients), and a splice site variant c.395 + 1G > T in intron 4(one patient). Another two novel variants were found in PDE6C: a homozygous missense variant c.1899C > A (p.His633Gln) in exon 15 (one patient) and a homozygous splice site variant c.1072-1G > C in intron 7 (one patient). Mutation segregation assessment was possible in 3 of the 7 families. All patients had nonrecordable ffERG 30-Hz flicker responses, reduced single-flash cone responses but preserved rod responses. Patients presented with variable degrees of foveal outer retinal layer loss and variable patterns of foveal hyperautofluorescence. Conclusions: These novel variants expand the genotypes associated with ACHM and may help in future therapy development for ACHM