Contribution of a Disk Component to Single Peaked Broad Lines of Active Galactic Nuclei

We study the disk emission component hidden in the single-peaked Broad Emission Lines (BELs) of Active Galactic Nuclei (AGN). We compare the observed broad lines from a sample of 90 Seyfert 1 spectra taken from the Sloan Digital Sky Survey with simulated line profiles. We consider a two-component Broad Line Region (BLR) model where an accretion disk and a surrounding non-disk region with isotropic cloud velocities generate the simulated BEL profiles. The analysis is mainly based in measurements of the full widths (at 10%, 20% and 30% of the maximum intensity) and of the asymmetries of the line profiles. Comparing these parameters for the simulated and observed H$\alpha$ broad lines, we {found} that the hidden disk emission {may} be present in BELs even if the characteristic {of two peaked line profiles is} absent. For the available sample of objects (Seyfert 1 galaxies with single-peaked BELs), our study indicates that, {in the case of the hidden disk emission in single peaked broad line profiles}, the disk inclination tends to be small (mostly $i<25^\circ$) and that the contribution of the disk emission to the total flux should be smaller than the contribution of the surrounding region.Comment: 18 Figures, 1 Table, MNRAS-accepted. MNRAS-accepte

Original scientific paper

The effect of reversing current deposition on the apparent density of electrolytic copper powde

Dermoscopy of the Month

Melanonychia refers to a brown or black coloration of the nail plate caused by numerous factors. Regarding the arrangement of pigmentation, we can differentiate between total melanonychia, when pigmentation involves the whole nail plate, or transverse or longitudinal melanonychia, when pigmentation involves the nail in a form of transverse or longitudinal band of pigmentation, respectively. Since longitudinal melanonychia can be a sign of numerous benign and malignant lesions, it often poses a diagnostic challenge for a dermatologist. Herein, we report a case of a 13-year-old girl who developed longitudinal melanonychia on multiple nails after receiving a therapy with azithromycin

Glutamic acid 242 is a valve in the proton pump of cytochrome c oxidase

Aerobic life is based on a molecular machinery that utilizes oxygen as a terminal electron sink. The membrane-bound cytochrome c oxidase (CcO) catalyzes the reduction of oxygen to water in mitochondria and many bacteria. The energy released in this reaction is conserved by pumping protons across the mitochondrial or bacterial membrane, creating an electrochemical proton gradient that drives production of ATP. A crucial question is how the protons pumped by CcO are prevented from flowing backwards during the process. Here, we show by molecular dynamics simulations that the conserved glutamic acid 242 near the active site of CcO undergoes a protonation state-dependent conformational change, which provides a valve in the pumping mechanism. The valve ensures that at any point in time, the proton pathway across the membrane is effectively discontinuous, thereby preventing thermodynamically favorable proton back-leakage while maintaining an overall high efficiency of proton translocation. Suppression of proton leakage is particularly important in mitochondria under physiological conditions, where production of ATP takes place in the presence of a high electrochemical proton gradient