6 research outputs found

    Supermassive Binaries and Extragalactic Jets

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    Some quasars show Doppler shifted broad emission line peaks. I give new statistics of the occurrence of these peaks and show that, while the most spectacular cases are in quasars with strong radio jets inclined to the line of sight, they are also almost as common in radio-quiet quasars. Theories of the origin of the peaks are reviewed and it is argued that the displaced peaks are most likely produced by the supermassive binary model. The separations of the peaks in the 3C 390.3-type objects are consistent with orientation-dependent "unified models" of quasar activity. If the supermassive binary model is correct, all members of "the jet set" (astrophysical objects showing jets) could be binaries.Comment: 31 pages, PostScript, missing figure is in ApJ 464, L105 (see http://www.aas.org/ApJ/v464n2/5736/5736.html

    Influence of renal denervation on blood pressure, sodium and water excretion in acute total obstructive apnea in rats

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    Obstructive apnea (OA) can exert significant effects on renal sympathetic nerve activity (RSNA) and hemodynamic parameters. The present study focuses on the modulatory actions of RSNA on OA-induced sodium and water retention. The experiments were performed in renal-denervated rats (D; N = 9), which were compared to sham (S; N = 9) rats. Mean arterial pressure (MAP) and heart rate (HR) were assessed via an intrafemoral catheter. A catheter was inserted into the bladder for urinary measurements. OA episodes were induced via occlusion of the catheter inserted into the trachea. After an equilibration period, OA was induced for 20 s every 2 min and the changes in urine, MAP, HR and RSNA were recorded. Renal denervation did not alter resting MAP (S: 113 &#177; 4 vs D: 115 &#177; 4 mmHg) or HR (S: 340 &#177; 12 vs D: 368 &#177; 11 bpm). An OA episode resulted in decreased HR and MAP in both groups, but D rats showed exacerbated hypotension and attenuated bradycardia (S: -12 &#177; 1 mmHg and -16 &#177; 2 bpm vs D: -16 &#177; 1 mmHg and 9 &#177; 2 bpm; P < 0.01). The basal urinary parameters did not change during or after OA in S rats. However, D rats showed significant increases both during and after OA. Renal sympathetic nerve activity in S rats increased (34 &#177; 9%) during apnea episodes. These results indicate that renal denervation induces elevations of sodium content and urine volume and alters bradycardia and hypotension patterns during total OA in unconscious rats
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