2,014 research outputs found

    On the Column Density of AGN Outflows: the Case of NGC 5548

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    We re-analyze the HST high resolution spectroscopic data of the intrinsic absorber in NGC 5548 and find that the C IV absorption column density is at least four times larger than previously determined. This increase arises from accounting for the kinematical nature of the absorber and from our conclusion that the outflow does not cover the narrow emission line region in this object. The improved column density determination begins to bridge the gap between the high column densities measured in the X-ray and the low ones previously inferred from the UV lines. Combined with our findings for outflows in high luminosity quasars these results suggest that traditional techniques for measuring column densities: equivalent width, curve-of-growth and Gaussian modeling, are of limited value when applied to absorption associated with AGN outflows.Comment: Published ApJ version (566, 699), including a new figure with FUSE data and a useful algebraic expression for the optical depth solutio

    Functional interplay between NTP leaving group and base pair recognition during RNA polymerase II nucleotide incorporation revealed by methylene substitution.

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    RNA polymerase II (pol II) utilizes a complex interaction network to select and incorporate correct nucleoside triphosphate (NTP) substrates with high efficiency and fidelity. Our previous 'synthetic nucleic acid substitution' strategy has been successfully applied in dissecting the function of nucleic acid moieties in pol II transcription. However, how the triphosphate moiety of substrate influences the rate of P-O bond cleavage and formation during nucleotide incorporation is still unclear. Here, by employing β,γ-bridging atom-'substituted' NTPs, we elucidate how the methylene substitution in the pyrophosphate leaving group affects cognate and non-cognate nucleotide incorporation. Intriguingly, the effect of the β,γ-methylene substitution on the non-cognate UTP/dT scaffold (∼3-fold decrease in kpol) is significantly different from that of the cognate ATP/dT scaffold (∼130-fold decrease in kpol). Removal of the wobble hydrogen bonds in U:dT recovers a strong response to methylene substitution of UTP. Our kinetic and modeling studies are consistent with a unique altered transition state for bond formation and cleavage for UTP/dT incorporation compared with ATP/dT incorporation. Collectively, our data reveals the functional interplay between NTP triphosphate moiety and base pair hydrogen bonding recognition during nucleotide incorporation

    What Determines the Depth of BALs? Keck HIRES Observations of BALQSO 1603+300

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    We find that the depth and shape of the broad absorption lines (BALs) in BALQSO 1603+3002 are determined largely by the fraction of the emitting source which is covered by the BAL flow. In addition, the observed depth of the BALs is poorly correlated with their real optical depth. The implication of this result is that abundance studies based on direct extraction of column densities from the depth of the absorption troughs are unreliable. Our conclusion is based on analysis of unblended absorption features of two lines from the same ion (in this case the Si IV doublet), which allows unambiguous separation of covering factor and optical depth effects. The complex morphology of the covering factor as a function of velocity suggests that the BALs are produced by several physically separated outflows. The covering factor is ion dependent in both depth and velocity width. We also find evidence that in BALQSO 1603+3002 the flow does not cover the broad emission line region.Comment: 13 pages, 2 figures, accepted for publication in Ap

    № 197. Постанова про відмову у перегляді справи на Костянтина Бутвиненка від 10 липня 1958 р.

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    The criminal justice system in Western countries is ever more frequently facing the question of how to deal with immigrants’ cultural practices, such as honour killings, blood revenges and female circumcision, better known as ‘Female Genital Mutilation’, that are considered to be in violation of human rights. Especially practicing Female Genital Mutilation has been subjected to an intense debate in the last four decades. This debate culminated provisionally in the recently adopted resolution by the United Nations, which calls upon its member states to eliminate this practice. Despite such calls, the results of criminal enforcement in banning this practice diverge in many countries. This raise the question whether national views on citizenship and multiculturalism may offer an explanation for the divergent enforcement practices in the area of Female Genital Mutilation. This study pays in particular attention to the way France, England and the Netherlands have criminalised Female Genital Mutilation and whether the results of their legal approaches in banning this practice by using criminal law, can be declared from their particular notions of citizenship
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