The First Spectroscopically Resolved Sub-parsec Orbit of a Supermassive Binary Black Hole

One of the most intriguing scenarios proposed to explain how active galactic nuclei are triggered involves the existence of a supermassive binary black hole system in their cores. Here we present an observational evidence for the first spectroscopically resolved sub-parsec orbit of a such system in the core of Seyfert galaxy NGC 4151. Using a method similar to those typically applied for spectroscopic binary stars we obtained radial velocity curves of the supermassive binary system, from which we calculated orbital elements and made estimates about the masses of components. Our analysis shows that periodic variations in the light and radial velocity curves can be accounted for an eccentric, sub-parsec Keplerian orbit of a 15.9-year period. The flux maximum in the lightcurve correspond to the approaching phase of a secondary component towards the observer. According to the obtained results we speculate that the periodic variations in the observed H{\alpha} line shape and flux are due to shock waves generated by the supersonic motion of the components through the surrounding medium. Given the large observational effort needed to reveal this spectroscopically resolved binary orbital motion we suggest that many such systems may exist in similar objects even if they are hard to find. Detecting more of them will provide us with insight into black hole mass growth process.Comment: 29 pages, 10 figures, published in ApJ, 759, 11

Association of prooxidant-antioxidant disorders with the development of morphofunctional disorders in rats with subtotal cerebral ischemia

The aim of the study was to investigate morphofunctional disorders of neurons in the cerebral cortex and changes in the prooxidant-antioxidant state in rats after subtotal cerebral ischemia. Material and methods. The experiments were performed on 20 white outbred male rats. Surgical interventions were carried out under intravenous thiopental anesthesia (40–50 mg/kg). Subtotal cerebral ischemia was simulated by both common carotid arteries ligation. Animals were decapitated after 60 minutes of ischemia. Morphological and functional changes in the neurons of the parietal cortex and hippocampal CA1 field, and intensity of free radical oxidative processes (content of thiobarbituric acid reactive substances and thiol-disulfide system components) in brain homogenates were studied. Results and discussion. Brain ischemia has been followed by oxidative stress in brain tissue. The cellular metabolism has been disturbed under the oxidative stress that leads to a water-electrolyte imbalance, manifested by deformation of neuron bodies, wrinkling, and swelling. The changes in parietal cortex are to a greater extent expressed, as the neurons are more sensitive to oxygen deficiency

Effects of Experemental Cerebral Ishemia on Metabolic Characteristics of Parietal Cortex Neurons

Cerebral Ischemia, Parietal Cortex, NeuronsThe aim of the paper was to estimate the effect of experimental cerebral ischemia on metabolic characteristics ofparietal cortex neurons. The experiments were carried out on 12 laboratory male rats. Cerebral ischemia was modeled with bilateral joint carotid arteries with durations of 60 minutes under intravenous thiopental anesthesia (40-50 mg / kg). The ratswere decapitated and the samples of the brain parietal cortex were prepared for histological and histochemical examination incombination with morphometry to examine the 5th layer inner pyramidal neurons. It was increased the number of pathological forms and shrinkage of the 5th layer inner pyramidal neurons after cerebral ischemia in rats. The histochemical examination was revealed the inhibition of NADH-, glucose-6-phosphate dehydrogenase and succinate dehydrogenases as well as activation of lactate dehydrogenase and acid phosphatase. Cerebral ischemia induces deep histological and histochemical changes in the parietal cortex neurons in rats, including shrinkage of parietal cortex neurons and disturbances of their energy metabolism

Morphological features of parietal cortex and hippocampus neuron of rats following subtotal cerebral ischemia associated with omega-3 polyunsaturated fatty acids injection

Aim of the study was to investigate the morphological features of neurons of the parietal cortex and hippocampus of rats with subtotal cerebral ischemia (SACI) during administration of omega-3 polyunsaturated fatty acids (omega-3 PUFA). Materials and methods. The experiments were performed on 24 white outbred male rats. Surgical interventions were carried out under conditions of intravenous thiopental anesthesia (40–50 mg/kg). Acute SACI was modeled by bilateral ligation of the common carotid arteries. The animals of the main group (n = 6, SACI + omega-3 PUFA) received intragastric injections of omega-3 PUFA preparation at a dose of 5 mg/kg body weight prior to ischemia for a week. In the comparison group (n = 6, SACI), the drug was not used; the control (n = 6) was sham operated animals, which were incised without skin ligation. Animals were decapitated after 60 minutes of ischemia. In rats, morphological changes in the neurons of the parietal cortex and the CA1 field of the hippocampus were studied. For morphometric and histochemical studies, animals were quickly removed after decapitation of the brain, pieces of the anterior cortex of the cerebral hemispheres were fixed in Carnoy fluid. Serial paraffin sections were stained with 0.1 % toluidine blue according to the Nissl method. Statistical hypothesis testing was performed using the Kruskal-Wallis ANOVA test. Results and discussion. The morphological and functional disorders in the parietal cortex and hippocampus have been revealed in animals of both experimental groups. The appointment of omega-3 did not significantly affect the size and shape of neurons in both the parietal cortex and the hippocampus. In the hippocampus, the administration of omega-3 polyunsaturated fatty acids resulted in a decrease in the number of hyperchromic shriveled neurons (by 20%) and an increase in hyperchromic neurons by 31 %. The number of shadow cells in this section did not differ from the indices of the control group. In the parietal cortex, no corrective effect was noted. Conclusions. Thus, subtotal cerebral ischemia leads to the development of morphofunctional disorders of the cerebral cortex. Administration of omega-3 had a positive effect on the state of rat hippocampal neurons, reducing the number of degenerative forms of neurons. The data obtained can serve as the basis for the search for new approaches to the treatment of acute ischemic stroke, which is one of the urgent problems of experimental and clinical neurology

Shocked Molecular Gas in the Supernova Remnant HB 21

We report the discovery of the shocked molecular gas in the supernova remnant HB 21. We derive the physical parameters of the shocked gas from CO J=1-0 and J=2-1 line observations. We discuss the correlation of the shocked molecular gas with the previously detected, shocked atomic gas and the associated infrared emission.Comment: 24 pages, 10 figures, To appear in the ApJ, scheduled for the April 10, 2001 issue (v551

ASSESSMENT OF STREAM FISH MORTALITY FROM SHORT-TERM EXPOSURE TO ILLITE CLAYS USED AS AN IN SITU METHOD FOR REMEDIATING 137CS CONTAMINATED WETLANDS

Due to their physical properties, illite clays can sorb cesium-137 almost irreversibly, and therefore sequester contamination from the environment. However, applying large amounts of clay to natural aquatic habitats for in situ remediation purposes may create conditions of high turbidity and sedimentation. To evaluate potential effects of turbidity from illite application on survivorship of stream fish, yellowfin shiners (Notropis lutipinnis) and tessellated darters (Etheostoma olmstedi) were subjected to treatment with two different types of clay in flow-through simulated stream raceways. Turbidity and fish mortality were subsequently monitored for seven days. At 2-m downstream from the application point, mean turbidity peaked during clay application at 525 and 72 nephelometric turbidity units (NTU) in the air-floated illite and semi-dry illite treatments, respectively. Turbidity returned to levels similar to that of the controls (4-6 NTU) after four hours in the air-floated illite raceways and one hour in the semi-dry illite raceways. Although the majority of the suspended clay was quickly flushed from the system and the remaining settled to the bottom, turbidity did continue to fluctuate because of fish movements and sediment resuspension. Fish mortality did not significantly differ among control and illite treated raceways

Validity of the rigid band picture for the t-J model

We present an exact diagonalization study of the doping dependence of the single particle Green's function in 16, 18 and 20 site clusters of t-J model. We find evidence for rigid-band behaviour starting from the half-filled case: upon doping, the topmost states of the quasiparticle band observed in the photoemisson spectrum at half-filling cross the chemical potential and reappear as the lowermost states of the inverse photoemission spectrum. Features in the inverse photoemission spectra which are inconsistent with rigid-band behaviour are shown to originate from the nontrivial point group symmetry of the ground state with two holes, which enforces different selection rules than at half-filling. Deviations from rigid band behaviour which lead to the formation of the `large Fermi surface' in the momentum distribution occur only at energies far from the chemical potential. A Luttinger Fermi surface and a nearest neighbor hopping band do not exist.Comment: Remarks: Revtex file + 7 figures attached as compressed postscript files Figures can also be obtained by ordinary mail on reques

Hole-Hole Contact Interaction in the t-J Model

Using an analytical variational approach we calculate the hole-hole contact interaction on the N\'{e}el background. Solution of the Bethe-Salpeter equation with this interaction gives bound states in $d$- and p-waves with binding energies close to those obtained by numerical methods. At $t/J \ge 2-3$ the bound state disappears. In conclusion we discuss the relation between short range and long range interactions and analogy with the problem of pion condensation in nuclear matter.Comment: 11 pp. (LATEX), 7 figures (PostScript) appended, report N

Morphological disturbances of rat parietal cortex and hippocampus neurons in the dynamics steady subtotal ischemia of the brain

The purpose of the work is to analyze changes in the morphological characteristics of neurons of phylogenetical different parts of the cerebral cortex (parietal cortex and hippocampus) of rats at different periods in the dynamics of stepwise subtotal experimental cerebral ischemia. Methods. The experiments were performed on 42 males of outbred white rats. Step subtotal cerebral ischemia was performed as follows: first, one common carotid artery was ligated, simulating partial ischemia. Then, with an interval of 1 day (subgroup 1), 3 days (subgroup 2) or 7 days (subgroup 3), the second common carotid artery was ligated. Results. A microscopic study of the size, shape, degree of chromatophilia of the cytoplasm and the content of ribonucleoproteins in pyramidal neurons of phylogenetically different parts of the cerebral cortex have shown the dependence of the severity of brain damage on the interval between the cessation of blood flow in both carotid artery. Adaptation was better with a 7-day interval between dressings, while the ligation with an interval of 1 day, the degree of morphological changes was maximum indicating a lack of resources for the implementation of adaptation mechanisms

Pierce the ear and stab the spleen

Splenic abscess is a rare but extremely dangerous condition generally spreading from a local, or systemic, focus of infection. We present the case of a young immunocompetent female admitted with sepsis and multiple splenic abscesses. The patient had a recent left ear piercing on the tragus complicated by an ear infection. The presence of a solitary parotid abscess, the absence of other infectious foci on computed tomography scan, the negativity of blood cultures and the absence of endocarditis vegetations led us to think that the most likely culprit was a hematogenous dissemination from the left tragus. The patient was successfully treated with intravenous antibiotics. There had been no need of splenectomy or any other procedure. This rather unique case underscores that splenic abscess should be suspected when a long-lasting fever and pain in the left hypochondrium are present, even when an apparently innocuous invasive procedure, such as a body piercing, is performed