The effects of different pot length and growing media on seedling quality of Crimean juniper (Juniperus excelsa Bieb.)

The aim of this study was to determine appropriate pot length and growing medium for Crimean Juniper seedlings (Juniperus excelsa Bieb.), which will be used for afforestation of extreme areas. For this purpose, polyethylene pots of 11 cm width and 20, 25 and 30 cm lengths were used. As growing medium, 13 different treatments were used, containing different ratios of forest soil, pumice, creek sand and humus collected from the species’ natural forest environments. The experimental design was a randomized block with 3 replications under open field conditions. Some morphological properties of the seedlings, such as seedling height, root collar diameter, shoot and root fresh and dry weights and shoot/root ratios (fresh and dry weights) were measured on 1 + 0 year old seedlings. Statistical analyses indicated that when pot length increased, the seedling quality improved. The seedlings with the best quality in terms of the measured criteria can be grown in 11 cm x 30 cm pots. In respect to the growing media, 70% forest soil + 15% humus + 15% pumice or creek sand should be used

Enhanced accretion rates of stars on Super-massive Black Holes by star-disk interactions in galactic nuclei

We investigate the dynamical interaction of a central star cluster surrounding a super-massive black hole and a central accretion disk. The dissipative force acting on stars in the disk leads to an enhanced mass flow towards the super-massive black hole and to an asymmetry in the phase space distribution due to the rotating accretion disk. The accretion disk is considered as a stationary Keplerian rotating disk, which is vertically extended in order to employ a fully self-consistent treatment of stellar dynamics including the dissipative force originating from star-gas ram pressure effects. The stellar system is treated with a direct high-accuracy N-body integration code. A star-by-star representation, desirable in N-body simulations, cannot be extended to real particle numbers yet. Hence, we carefully discuss the scaling behavior of our model with regard to particle number and tidal accretion radius. The main idea is to find a family of models for which the ratio of two-body relaxation time and dissipation time (for kinetic energy of stellar orbits) is constant, which then allows us to extrapolate our results to real parameters of galactic nuclei. Our model is derived from basic physical principles and as such it provides insight into the role of physical processes in galactic nuclei, but it should be regarded as a first step towards more realistic and more comprehensive simulations. Nevertheless, the following conclusions appear to be robust: the star accretion rate onto the accretion disk and subsequently onto the super-massive black hole is enhanced by a significant factor compared to purely stellar dynamical systems neglecting the disk. This process leads to enhanced fueling of central disks in active galactic nuclei and to an enhanced rate of tidal stellar disruptions. [Abridged]Comment: 17 pages, 6 figures (with 9 panels), 2 tables, accepted for publication in Ap

The evaluation of morphology of renal pelvicalyceal system’s and infundibulopelvic anatomy of kidney’s lower pole in post-mortem series

Background: Urinary system stones are frequently encountered in the community. Together with technological developments, introduction of new treatment procedures such as extracorporeal shock wave lithotripsy, percutaneous nephrolithotomy and retrograde intrarenal surgery has furtherly reduced morbidity, mortality and hospitalization time of patients. In order to maximize success and to reduce complications of these procedures, it is necessary to evaluate anatomy and morphological differences of kidney collector system before the procedure. This study was conducted for the purpose of determining the morphology of the kidney collector system and the negative anatomic factors of the lower pole in autopsy cases performed in our institution. Materials and methods: 82 kidney units obtained from 41 autopsy cases conducted in Faculty of Medicine Department of Forensic Medicine, Sivas Cumhuriyet University between September 2017 and September 2018 were included in the study. Percentages were found as 78% for intrarenal pelvis, 13.4% for borderline pelvis, %6.1 for extrarenal pelvis and 2.4% for pelvic nonexistence. When pelvicalyceal anatomy was evaluated, percentages were found as 32.9% for bicalyceal, 26.8% for tricalyceal, 20.7% for multicalyceal and 19.5% for unclassified calyceality. When it is evaluated according to opening of calyces into the renal pelvis based on Sampaio classification, percentages were found as 30.5% for AI, 17.1% for Type II, 28% for BI, 18.3% for BII and 6.1% for unevaluated part. Infundibular lengths of kidney’s lower pole were detected as under 3 cm in 39% and over 3 cm in 61% of all cases. Infundibulopelvic angles of kidney’s lower pole were measured as under 700 in 42.7% and over 700 in 57.3% of all cases. Results: In our study, there was no statistically significant difference between the right and left kidneys in terms of collecting system morphology and lower pole’s negative anatomical factors. Only infindibular lengths which is one of the collecting system morphology and lower pole’s negative anatomical factors were statistically shorter in females than males. There was no difference in terms of other parameters. Conclusions: In conclusion, the findings of this study are largely consistent with the results of similar studies. This reveals that renal collecting system morphology and negative anatomic factors in the lower pole collecting system in human are roughly similar. In clinical practice, pre-treatment CT and, if necessary, MR urography evaluation of the lower pole negative anatomic factors may contribute to gain preliminary information about both the clearance of stone fragments especially after SWL and RIRS procedures and perioperative complications proactively

The Megamaser Cosmology Project. III. Accurate Masses of Seven Supermassive Black Holes in Active Galaxies with Circumnuclear Megamaser Disks

Observations of H$_2$O masers from circumnuclear disks in active galaxies for the Megamaser Cosmology Project allow accurate measurement of the mass of supermassive black holes (BH) in these galaxies. We present the Very Long Baseline Interferometry (VLBI) images and kinematics of water maser emission in six active galaxies: NGC~1194, NGC~2273, NGC~2960 (Mrk~1419), NGC~4388, NGC~6264 and NGC~6323. We use the Keplerian rotation curves of these six megamaser galaxies, plus a seventh previously published, to determine accurate enclosed masses within the central $\sim0.3$ pc of these galaxies, smaller than the radius of the sphere of influence of the central mass in all cases. We also set lower limits to the central mass densities of between 0.12 and 60 $\times 10^{10} M_{\odot}$~pc$^{-3}$. For six of the seven disks, the high central densities rule out clusters of stars or stellar remnants as the central objects, and this result further supports our assumption that the enclosed mass can be attributed predominantly to a supermassive black hole. The seven BHs have masses ranging between 0.76 and 6.5$\times$10$^7 M_{\odot}$. The BH mass errors are $\approx11$\%, dominated by the uncertainty of the Hubble constant. We compare the megamaser BH mass determination with other BH mass measurement techniques. The BH mass based on virial estimation in four galaxies is consistent with the megamaser BH mass given the latest empirical value of $\langle f \rangle$, but the virial mass uncertainty is much greater. MCP observations continue and we expect to obtain more maser BH masses in the future.Comment: 18 pages, 4 figures. This paper has been submitted to ApJ. An updated version of this paper will be posted when it gets accepte

Constraints on the faint end of the quasar luminosity function at z~5 in the COSMOS field

We present the result of our low-luminosity quasar survey in the redshift range of 4.5 < z < 5.5 in the COSMOS field. Using the COSMOS photometric catalog, we selected 15 quasar candidates with 22 < i' < 24 at z~5, that are ~ 3 mag fainter than the SDSS quasars in the same redshift range. We obtained optical spectra for 14 of the 15 candidates using FOCAS on the Subaru Telescope and did not identify any low-luminosity type-1 quasars at z~5 while a low-luminosity type-2 quasar at z~5.07 was discovered. In order to constrain the faint end of the quasar luminosity function at z~5, we calculated the 1sigma confidence upper limits of the space density of type-1 quasars. As a result, the 1sigma confidence upper limits on the quasar space density are Phi< 1.33*10^{-7} Mpc^{-3} mag^{-1} for -24.52 < M_{1450} < -23.52 and Phi< 2.88*10^{-7} Mpc^{-3} mag^{-1} for -23.52 < M_{1450} < -22.52. The inferred 1sigma confidence upper limits of the space density are then used to provide constrains on the faint-end slope and the break absolute magnitude of the quasar luminosity function at z~5. We find that the quasar space density decreases gradually as a function of redshift at low luminosity (M_{1450} ~ -23), being similar to the trend found for quasars with high luminosity (M_{1450}<-26). This result is consistent with the so-called downsizing evolution of quasars seen at lower redshifts.Comment: 8 pages, 9 figures, 1 table, accepted for publication in Ap

Precise Black Hole Masses From Megamaser Disks: Black Hole-Bulge Relations at Low Mass

The black hole (BH)-bulge correlations have greatly influenced the last decade of effort to understand galaxy evolution. Current knowledge of these correlations is limited predominantly to high BH masses (M_BH> 10^8 M_sun) that can be measured using direct stellar, gas, and maser kinematics. These objects, however, do not represent the demographics of more typical L< L* galaxies. This study transcends prior limitations to probe BHs that are an order of magnitude lower in mass, using BH mass measurements derived from the dynamics of H_2O megamasers in circumnuclear disks. The masers trace the Keplerian rotation of circumnuclear molecular disks starting at radii of a few tenths of a pc from the central BH. Modeling of the rotation curves, presented by Kuo et al. (2010), yields BH masses with exquisite precision. We present stellar velocity dispersion measurements for a sample of nine megamaser disk galaxies based on long-slit observations using the B&C spectrograph on the Dupont telescope and the DIS spectrograph on the 3.5m telescope at Apache Point. We also perform bulge-to-disk decomposition of a subset of five of these galaxies with SDSS imaging. The maser galaxies as a group fall below the M_BH-sigma* relation defined by elliptical galaxies. We show, now with very precise BH mass measurements, that the low-scatter power-law relation between M_BH and sigma* seen in elliptical galaxies is not universal. The elliptical galaxy M_BH-sigma* relation cannot be used to derive the BH mass function at low mass or the zeropoint for active BH masses. The processes (perhaps BH self-regulation or minor merging) that operate at higher mass have not effectively established an M_BH-sigma* relation in this low-mass regime.Comment: 21 pages, 14 figures, accepted for publication in the Astrophysical Journa

Ram pressure feeding super-massive black holes

When supermassive black holes at the center of galaxies accrete matter (usually gas), they give rise to highly energetic phenomena named Active Galactic Nuclei (AGN). A number of physical processes have been proposed to account for the funneling of gas towards the galaxy centers to feed the AGN. There are also several physical processes that can strip gas from a galaxy, and one of them is ram pressure stripping in galaxy clusters due to the hot and dense gas filling the space between galaxies. We report the discovery of a strong connection between severe ram pressure stripping and the presence of AGN activity. Searching in galaxy clusters at low redshift, we have selected the most extreme examples of jellyfish galaxies, which are galaxies with long tentacles of material extending for dozens of kpc beyond the galaxy disk. Using the MUSE spectrograph on the ESO Very Large Telescope, we find that 6 out of the 7 galaxies of this sample host a central AGN, and two of them also have galactic-scale AGN ionization cones. The high incidence of AGN among the most striking jellyfishes may be due to ram pressure causing gas to flow towards the center and triggering the AGN activity, or to an enhancement of the stripping caused by AGN energy injection, or both. Our analysis of the galaxy position and velocity relative to the cluster strongly supports the first hypothesis, and puts forward ram pressure as another, yet unforeseen, possible mechanism for feeding the central supermassive black hole with gas.Comment: published in Nature, Vol.548, Number 7667, pag.30

Can we Detect Intermediate Mass Ratio Inspirals?

Gravitational waves emitted during intermediate-mass-ratio inspirals (IMRIs) of intermediate-mass black holes (IMBHs) into supermassive black holes could represent a very interesting source for LISA. Similarly, IMRIs of stellar-mass compact objects into IMBHs could be detectable by Advanced LIGO. At present, however, it is not clear what waveforms could be used for IMRI detection, since the post-Newtonian approximation breaks down as an IMRI approaches the innermost stable circular orbit, and perturbative solutions are only known to the lowest order in the mass ratio. We discuss the expected mismatches between approximate and true waveforms, and the choice of the best available waveform as a function of the mass ratio and the total mass of the system. We also comment on the significance of the spin of the smaller body and the need for its inclusion in the waveforms.Comment: Updated to match published versio