Study of relativistic bound state wave functions in quasielastic (e,e'p) reactions

The unpolarized response functions of the quasielastic $^{16}O(e,e^\prime p)^{15}N$ reaction are calculated for three different types of relativistic bound state wave functions. The wave functions are obtained from relativistic Hartree, relativistic Hartree-Fock and density dependent relativistic Hartree calculations that reproduce the experimental charge radius of $^{16}$O. The sensitivity of the unpolarized response functions to the single particle structure of the different models is investigated in the relativistic plane wave impulse approximation. Redistributions of the momentum dependence in the longitudinal and transverse response function can be related to the binding energy of the single particle states. The interference responses $R_{LT}$ and $R_{TT}$ reveal a strong sensitivity to the small component of the relativistic bound state wave function.Comment: 18 pages REVTEX, 5 figures include

Koordinationschemie -gebundener Cyclopentadienyl-Chalkogeno-Ether

Coordination Chemistry of rr-Bonded Cyclopentadienyl Chalcogeno Ethers, I. - Chelate Complexes of Pentakis(methylthio)cymantrene with Metal Carbonyls [C5(SMe)5]Mn(CO)3 (1) reacts with W(CO)5(THF), Mo(CO)4(C7H8), Cr(CO)3(NCMe)3, and Re(CO)4(-C3H5)/HBF4 to yield the monochelate complexes [[C5(SMe)5]Mn(C0)3][M(CO)4] (M = W: 2; M = Mo: 3) and the dichelate complexes [[C5(SMe)5]Mn(CO)3][M(C0)4]2 (M = W: 4; M = Cr: 5; M = Re BFF4 : 6). The reaction with Mo(CO)3(p-xylene) in THF leads via unstable intermediates, which contain coordinated THF, to a mixture of 3 and [[C5(SMe)5]Mn(CO)3][Mo(CO)4]2 (7). The structures of 3 and 4 in the crystal have been determined by X-ray diffraction methods

The broad iron Kalpha line of Cygnus X-1 as seen by XMM-Newton in the EPIC-pn modified timing mode

We present the analysis of the broadened, flourescent iron Kalpha line in simultaneous XMM-Newton and RXTE data from the black hole Cygnus X-1. The XMM-Newton data were taken in a modified version of the timing mode of the EPIC-pn camera. In this mode the lower energy threshold of the instrument is increased to 2.8 keV to avoid telemetry drop outs due to the brightness of the source, while at the same time preserving the signal-to-noise ratio in the Fe Kalpha band. We find that the best-fit spectrum consists of the sum of an exponentially cut off power-law and relativistically smeared, ionized reflection. The shape of the broadened Fe Kalpha feature is due to strong Compton broadening combined with relativistic broadening. Assuming a standard, thin accretion disk, the black hole is close to rotating maximally.Comment: Astron. Astrophys., in pres

The Padova-Millennium Galaxy and Group Catalogue (PM2GC): the group-finding method and the PM2GC catalogues of group, binary and single field galaxies

We present the construction and describe the properties of the Padova-Millennium Galaxy and Group Catalogue (PM2GC), a galaxy catalogue representative of the general field population in the local Universe. We characterize galaxy environments by identifying galaxy groups at 0.04<=z<=0.1 with a Friends-of-Friends (FoF) algorithm using a complete sample of 3210 galaxies brighter than MB = -18.7 taken from the Millennium Galaxy Catalogue (MGC, Liske et al. (2003)), a 38deg^2 photometric and spectroscopic equatorial survey. We identified 176 groups with at least three members, comprising in total 1057 galaxies and representing ~43 per cent of the general field population in that redshift range. The median redshift and velocity dispersion of our groups are 0.0823 and 192 km s^-1, respectively. 88 per cent of the groups have fewer than ten members, and 63 per cent have fewer than five members. Nongroup galaxies were subdivided into "inary" systems of two bright close companions, and "single" galaxies with no companion, in order to identify different environments useful for future scientific analysis. We performed a detailed comparison with the 2PIGG catalogue to validate the effectiveness of our method and the robustness of our results. Galaxy stellar masses are computed for all PM2GC galaxies, and found to be in good agreement with Sloan Digital Survey Data Release 7 (SDSS-DR7) mass estimates. The catalogues of PM2GC groups, group properties and galaxy properties in all environments are publicly available on theWorld Wide Web.Comment: 14 pages, 7 figures, 6 tables. MNRAS accepted, in press. Tables 2, 3, 4, 5, 6 early available or on request to autho

Arrangement of Annexin A2 tetramer and its impact on the structure and diffusivity of supported lipid bilayers

Annexins are a family of proteins that bind to anionic phospholipid membranes in a Ca2+-dependent manner. Annexin A2 forms heterotetramers (Anx A2t) with the S100A10 (p11) protein dimer. The tetramer is capable of bridging phospholipid membranes and it has been suggested to play a role in Ca2+-dependent exocytosis and cell-cell adhesion of metastatic cells. Here, we employ x-ray reflectivity measurements to resolve the conformation of Anx A2t upon Ca2+-dependent binding to single supported lipid bilayers (SLBs) composed of different mixtures of anionic (POPS) and neutral (POPC) phospholipids. Based on our results we propose that Anx A2t binds in a side-by-side configuration, i.e., both Anx A2 monomers bind to the bilayer with the p11 dimer positioned on top. Furthermore, we observe a strong decrease of lipid mobility upon binding of Anx A2t to SLBs with varying POPS content. X-ray reflectivity measurements indicate that binding of Anx A2t also increases the density of the SLB. Interestingly, in the protein-facing leaflet of the SLB the lipid density is higher than in the substrate-facing leaflet. This asymmetric densification of the lipid bilayer by Anx A2t and Ca2+ might have important implications for the biochemical mechanism of Anx A2t-induced endo- and exocytosis.Comment: 27 pages, 7 figures; supplementary material available upon request from the author