5,519 research outputs found

    Topische Therapie bei chronisch-entzündlichen Darmerkrankungen: Ein häufig unterschätzter Therapiebaustein

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    Zusammenfassung: Die Inzidenz und Prävalenz der Colitis ulcerosa nimmt sowohl in westlichen Ländern als auch in Entwicklungsländern zu. Grundstein der Behandlung ist die Anwendung von Aminosalicylaten (5-ASA). Alternativ können auch steroidhaltige topische Therapien eingesetzt werden. Häufig werden 5-ASA-Präparate nur peroral verabreicht, obschon insbesondere bei Proktitis und linksseitiger Kolitis topische (oder rektale) 5-ASA-Präparate sogar effizienter sind als perorale/systemische. Dies gilt sowohl für die Remissionsinduktion wie auch für die remissionserhaltende Therapie. Zahlreiche Untersuchungen in Kohorten oder größeren Behandlungszentren zeigen, dass topische Therapien zu selten eingesetzt werden. Insbesondere bei der ausgedehnten Kolitis sollten perorale und topische Therapien kombiniert Anwendung finden. In diesem Übersichtsartikel fassen wir die Evidenz der topischen Therapie bei der Colitis ulcerosa mit 5-ASA und Steroiden zusammen. Damit kann die Therapie optimiert und die Akzeptanz einer topischen Therapie bei den Patienten verbessert werden. Diese ist nach entsprechender Aufklärung höher als generell vermutet wird. Nur bei schweren Kolitisverläufen hat eine topische Therapie keinen Stellenwert, da sie zum einen bei häufigen Darmentleerungen nicht ausreichend wirksam wäre und zum anderen von den Patienten schlecht toleriert wird. Die Evidenz für die Anwendung topischer Therapien bei Morbus Crohn ist unzureichen

    Vinogradov's three primes theorem with primes having given primitive roots

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    The first purpose of our paper is to show how Hooley's celebrated method leading to his conditional proof of the Artin conjecture on primitive roots can be combined with the Hardy-Littlewood circle method. We do so by studying the number of representations of an odd integer as a sum of three primes, all of which have prescribed primitive roots. The second purpose is to analyse the singular series. In particular, using results of Lenstra, Stevenhagen and Moree, we provide a partial factorisation as an Euler product and prove that this does not extend to a complete factorisation

    A statistical method to search for recoiling supermassive black holes in active galactic nuclei

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    We propose an observational test for gravitationally recoiling supermassive black holes (BHs) in active galactic nuclei, based on a correlation between the velocities of BHs relative to their host galaxies, |Δv|, and their obscuring dust column densities, Σdust (both measured along the line of sight). We use toy models for the distribution of recoil velocities, BH trajectories, and the geometry of obscuring dust tori in galactic centres, to simulate 2.5 × 105 random observations of recoiling quasars. BHs with recoil velocities comparable to the escape velocity from the galactic centre remain bound to the nucleus, and do not fully settle back to the centre of the torus due to dynamical friction in a typical quasar lifetime. We find that |Δv| and Σdust for these BHs are positively correlated. For obscured (Σdust > 0) and for partially obscured (0 < Σdust ≲ 2.3 g m−2) quasars with |Δv| ≥ 45 km s−1, the sample correlation coefficient between log10(|Δv|) and Σdust is r45 = 0.28 ± 0.02 and r45 = 0.13 ± 0.02, respectively. Allowing for random ± 100 km s− 1 errors in |Δv| unrelated to the recoil dilutes the correlation for the partially obscured quasars to r45 = 0.026 ± 0.004 measured between |Δv| and Σdust. A random sample of ≳ 3500 obscured quasars with |Δv| ≥ 45 km s−1 would allow rejection of the no-correlation hypothesis with 3σ significance 95 per cent of the time. Finally, we find that the fraction of obscured quasars, obs (|Δv|), decreases with |Δv| from obs (103 km s−1) ≲ 0.4. This predicted trend can be compared to the observed fraction of type II quasars, and can further test combinations of recoil, trajectory, and dust torus models

    Granite-hosted gold mineralization in the Midlands greenstone belt: a new type of low-grade gold deposit in Zimbabwe

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    In 1992, the Ford gold deposit was rediscovered during field work in the Kwekwe district near the Indarama mine, approximately 200 km southwest of Harare, Zimbabwe. Based on diamond drilling and open pit operations, estimated ore reserves are at least 3 Mt with an average gold content of 2.5 g/t. The gold deposit is located within a porphyritic granite dike with a thickness of 20–50 m, striking 800 m NNW-SSE. It dips 60–70° to the NE and intrudes a volcano-sedimentary sequence of tholeiitic basalts, acid volcanics, and banded iron formations of the Bulawayan Group (2900–2700 Ma). The intrusion of the dike occurred at 2541 ± 17 Ma (Pb/Pb step leaching technique) within a second order structure and is related to displacement along transcrustal deformation zones such as the Sherwood- and Taba-Mali deformation zones. Gold mineralization is confined to the s-shaped part of the dike intrusion. At the present stage of mining, the deposit is characterized by the absence of major veins, the occurrence of disseminated pyrite throughout the orebody, and a distinct alteration pattern comparable to that of porphyry copper deposits. The central zone of the dike shows a typical K-feldspar-albite-sericite-pyrite (±biotite?) alteration, followed by a narrow external propylitic zone. Native gold with an average Ag content of 5 wt.% and a grain size of 5–100 μm is rare and occurs within pyrite and secondary K-feldspar. Sulphide mineral separates of pyrite and minor arsenopyrite probably contain invisible gold (up to 120 ppm) amenable to cyanidation. Anomalously high gold values of ∼7 ppm have been found in the transition between the K-feldspar-albite-sericite-pyrite alteration and the propylitic zone, indicating that the mineralizing fluids have experienced major physico-chemical changes in the transition zone. The regional tectonic position of the orebody suggests that the emplacement of the granite and the gold mineralization are structurally controlled. The Pb isotope composition of several leachates of pyrite indicate isotope disequilibrium with magmatic minerals and point to a contamination of the mineralizing fluid by Pb from older (sedimentary?) sources. Stable isotope geochemistry of sulphides and carbonates as well as the metallogeny of the deposit compare to shear-zone hosted gold mineralization in the Kwekwe district, for which a deep crustal origin has been discussed. Although this study documents contrasting evidence for a porphyry-gold versus a shear-zone type of mineralization, it is suggested that gold-bearing fluids were syntectonically introduced into a ductile shear zone within the granite dike either during cooling of the intrusion or later in Archaean or early Proterozoic times

    InSPIREd - advances in Conformal Printing: 3D printing onto unknown uneven surfaces

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    The term Conformal Printing refers to 3D printing onto uneven surfaces. Whilst some very high priced solutions exist for known uneven surfaces, where the toolpath is generated in advance, based on CAD data of the object to be printed onto, there is nothing available yet for conformal printing onto unknown uneven surfaces that are scanned on-the-fly. A low-cost prototype named 'InSPIREd' was recently developed to achieve this, made possible with a combination of multi-disciplinary expertise, ingenuity and problem tackling knowhow, and the latest improvements are presented in this paper. The prototype now includes more capable scanning technology and a simplified calibration procedure

    The non-destructive study of museums objects by means of neutrons imaging methods and results of investigations

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    Based on experience from many kinds of investigations with neutron imaging methods (radiography, tomography, time-dependent studies) and in comparison to conventional X-ray methods, the authors discuss the potential of future improved studies for cultural-heritage purposes. Whereas the focus of the paper is on the imaging aspect, other established techniques as neutron activation analysis (NAA), prompt gamma activation analysis (PGAA), neutron-induced autoradiography and neutron scattering are mentioned too. Although a great potential for studies similar to those described in the paper exists, a considerable effort is needed to define the best-suited methods for the dedicated cultural historical request. A real barrier between the experts at large research facilities (as, e.g., neutron sources are) and the partners from the museums side has to be overcome in order to solve the problems. A joint European approach will help in this respect

    GLADE: A galaxy catalogue for multimessenger searches in the advanced gravitational-wave detector era

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    We introduce a value-added full-sky catalogue of galaxies, named as Galaxy List for the Advanced Detector Era, or GLADE. The purpose of this catalogue is to (i) help identifications of host candidates for gravitational-wave events, (ii) support target selections for electromagnetic follow-up observations of gravitational-wave candidates, (iii) provide input data on the matter distribution of the local Universe for astrophysical or cosmological simulations, and (iv) help identifications of host candidates for poorly localized electromagnetic transients, such as gamma-ray bursts observed with the InterPlanetary Network. Both being potential hosts of astrophysical sources of gravitational waves, GLADE includes inactive and active galaxies as well. GLADE was constructed by cross-matching and combining data from five separate (but not independent) astronomical catalogues: GWGC, 2MPZ, 2MASS XSC, HyperLEDA, and SDSS-DR12Q. GLADE is complete up to dL=37+3−4Mpc in terms of the cumulative B-band luminosity of galaxies within luminosity distance dL, and contains all of the brightest galaxies giving half of the total B-band luminosity up to dL=91Mpc. As B-band luminosity is expected to be a tracer of binary neutron star mergers (currently the prime targets of joint GW+EM detections), our completeness measures can be used as estimations of completeness for containing all binary neutron star merger hosts in the local Universe
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