224 research outputs found

    Characterization of Megatrypanum trypanosomes from European Cervidae

    Get PDF
    Megatrypanum trypanosomes have been isolated from a number of different European Cervidae, but on the basis of morphology it has not been possible to define the species to which these isolates belong. We isolated Trypanosoma (Megatrypanum) theileri from 10 cattle, and Megatrypanum trypanosomes from 11 fallow deer (Cervus dama), 9 red deer (Cervus elaphus), and 4 roe deer (Capreolus capreolus) by blood culture on a biphasic medium (NNN agar slopes). Trypanosomes were propagated in Schneider's Drosophila medium and characterized by isoenzyme analysis and molecular karyotyping. Isocitrate dehydrogenase and phosphoglucomutase were visualized after starch gel electrophoresis of trypanosome lysates. By cluster analysis of this data all isolates from deer were clearly separated from the T. (M.) theileri isolates from cattle. Isolates from roe deer were different not only from T. (M.) theileri but also from the other deer isolates. Isolates from fallow deer and red deer were grouped together. Thus, there are probably at least two different species of Megatrypanum trypanosomes in the three Cervidae. One parasitizing roe deer, the other, apparently less host specific species, infecting red deer and fallow deer. Separation of the chromosomes of Megatrypanum trypanosomes by pulsed-field gradient gel electrophoresis (PFGE) showed that each isolate contained a large number (> 18) of chromosomes ranging in size from 300 to > 2200 kb. The molecular karyotypes were similar for all isolates, although no isolate was identical to anothe

    Seasonal Variations of Seismic Activity on Mars?

    Get PDF
    We analyze the sequence of seismic events of different types as recorded by the SEIS instrument of the InSight mission. After several weeks without any detection, event counts started to increase at the end of May 2019. The majority of recorded events belongs to the class of 2.4 Hz events, which prominently excite a continuously observed natural resonance frequency. Comparison with expected event counts from a constant-rate Poisson process shows a repeated, step wise increase of the event rate with time. At the same time, event amplitudes, and hence magnitudes, are found to increase as well

    Experimental constraints on the ω\omega-nucleus real potential

    Get PDF
    In a search for ω\omega mesic states, the production of ω\omega-mesons in coincidence with forward going protons has been studied in photon induced reactions on 12^{12}C for incident photon energies of 1250 - 3100 MeV. The π0Îł\pi^0 \gamma pairs from decays of bound or quasi-free ω\omega-mesons have been measured with the CBELSA/TAPS detector system in coincidence with protons registered in the MiniTAPS forward array. Structures in the total energy distribution of the π0Îł\pi^0 \gamma pairs, which would indicate the population and decay of bound ω 11\omega~^{11}B states, are not observed. The π0Îł\pi^0 \gamma cross section of 0.3 nb/MeV/sr observed in the bound state energy regime between -100 and 0 MeV may be accounted for by yield leaking into the bound state regime because of the large in-medium width of the ω\omega-meson. A comparison of the measured total energy distribution with calculations suggests the real part V0V_0 of the ω 11\omega~^{11}B potential to be small and only weakly attractive with V0(ρ=ρ0)=−15±V_0(\rho=\rho_0) = -15\pm 35(stat) ±\pm20(syst) MeV in contrast to some theoretical predictions of attractive potentials with a depth of 100 - 150 MeV.Comment: 13 pages, 8 figure

    First measurement of the helicity asymmetry for Îłp→pπ0\gamma p\rightarrow p\pi^0 in the resonance region

    Full text link
    The first measurement of the helicity dependence of the photoproduction cross section of single neutral pions off protons is reported for photon energies from 600 to 2300\,MeV, covering nearly the full solid angle. The data are compared to predictions from the SAID, MAID, and BnGa partial wave analyses. Strikingly large differences between data and predictions are observed which are traced to differences in the helicity amplitudes of well known and established resonances. Precise values for the helicity amplitudes of several resonances are reported

    The {\eta}'-carbon potential at low meson momenta

    Full text link
    The production of ηâ€Č\eta^\prime mesons in coincidence with forward-going protons has been studied in photon-induced reactions on 12^{12}C and on a liquid hydrogen (LH2_2) target for incoming photon energies of 1.3-2.6 GeV at the electron accelerator ELSA. The ηâ€Č\eta^\prime mesons have been identified via the ηâ€Č→π0π0η→6Îł\eta^\prime\rightarrow \pi^0 \pi^0\eta \rightarrow 6 \gamma decay registered with the CBELSA/TAPS detector system. Coincident protons have been identified in the MiniTAPS BaF2_2 array at polar angles of 2∘≀Ξp≀11∘2^{\circ} \le \theta _{p} \le 11^{\circ}. Under these kinematic constraints the ηâ€Č\eta^\prime mesons are produced with relatively low kinetic energy (≈\approx 150 MeV) since the coincident protons take over most of the momentum of the incident-photon beam. For the C-target this allows the determination of the real part of the ηâ€Č\eta^\prime-carbon potential at low meson momenta by comparing with collision model calculations of the ηâ€Č\eta^\prime kinetic energy distribution and excitation function. Fitting the latter data for ηâ€Č\eta^\prime mesons going backwards in the center-of-mass system yields a potential depth of V = −-(44 ±\pm 16(stat)±\pm15(syst)) MeV, consistent with earlier determinations of the potential depth in inclusive measurements for average ηâ€Č\eta^\prime momenta of ≈\approx 1.1 GeV/cc. Within the experimental uncertainties, there is no indication of a momentum dependence of the ηâ€Č\eta^\prime-carbon potential. The LH2_2 data, taken as a reference to check the data analysis and the model calculations, provide differential and integral cross sections in good agreement with previous results for ηâ€Č\eta^\prime photoproduction off the free proton.Comment: 9 pages, 13 figures. arXiv admin note: text overlap with arXiv:1608.0607

    The polarization observables T, P, and H and their impact on Îłp→pπ0\gamma p \to p\pi^0 multipoles

    Full text link
    Data on the polarization observables T, P, and H for the reaction Îłp→pπ0\gamma p\to p\pi^0 are reported. Compared to earlier data from other experiments, our data are more precise and extend the covered range in energy and angle substantially. The results were extracted from azimuthal asymmetries measured using a transversely polarized target and linearly polarized photons. The data were taken at the Bonn electron stretcher accelerator ELSA with the CBELSA/TAPS detector. Within the Bonn-Gatchina partial wave analysis, the new polarization data lead to a significant narrowing of the error band for the multipoles for neutral-pion photoproduction

    The N(1520) 3/2- helicity amplitudes from an energy-independent multipole analysis based on new polarization data on photoproduction of neutral pions

    Full text link
    New data on the polarization observables T, P, and H for the reaction Îłp→pπ0\gamma p \to p\pi^0 are reported. The results are extracted from azimuthal asymmetries when a transversely polarized butanol target and a linearly polarized photon beam are used. The data were taken at the Bonn electron stretcher accelerator ELSA using the CBELSA/TAPS detector. These and earlier data are used to perform a truncated energy-independent partial wave analysis in sliced-energy bins. This energy-independent analysis is compared to the results from energy-dependent partial wave analyses

    Photoproduction of eta mesons from the neutron: cross sections and double polarization observable E

    Full text link
    Photoproduction of η\eta mesons from neutrons} \abstract{Results from measurements of the photoproduction of η\eta mesons from quasifree protons and neutrons are summarized. The experiments were performed with the CBELSA/TAPS detector at the electron accelerator ELSA in Bonn using the η→3π0→6Îł\eta\to3\pi^{0}\to6\gamma decay. A liquid deuterium target was used for the measurement of total cross sections and angular distributions. The results confirm earlier measurements from Bonn and the MAMI facility in Mainz about the existence of a narrow structure in the excitation function of Îłn→nη\gamma n\rightarrow n\eta. The current angular distributions show a forward-backward asymmetry, which was previously not seen, but was predicted by model calculations including an additional narrow P11P_{11} state. Furthermore, data obtained with a longitudinally polarized, deuterated butanol target and a circularly polarized photon beam were analyzed to determine the double polarization observable EE. Both data sets together were also used to extract the helicity dependent cross sections σ1/2\sigma_{1/2} and σ3/2\sigma_{3/2}. The narrow structure in the excitation function of Îłn→nη\gamma n\rightarrow n\eta appears associated with the helicity-1/2 component of the reaction

    The evaluation of European criminal law

    Get PDF
    The role of evaluation has become increasingly important in the context of EU policies in the field of judicial cooperation in criminal matters. This evolution is the result of an increasing number of legally binding instruments adopted in the framework of the third pillar of the European Union and of their growing impact on national legal systems
    • 

    corecore