Comment on the Black Hole Recoil Candidate Quasar SDSS J092712.65+294344.0

SDSS J092712.65+294344.0 has been proposed as a candidate for a supermassive black hole (~10^8.8 solar masses) ejected at high speed from the host galactic nucleus by gravitational radiation recoil, or alternatively for a supermassive black hole binary. This is based on a blueshift of 2650 km/s of the broad emission lines ("b-system") relative to the narrow emission lines ("r-system") presumed to reflect the galaxy velocity. New observations with the Hobby-Eberly Telescope (HET) confirm the essential features of the spectrum. We note a third redshift system, characterized by weak, narrow emission lines of [O III] and [O II] at an intermediate velocity 900 km/s redward of the broad line velocity ("i-system"). A composite spectrum of SDSS QSOs similar to J0927 illustrates the feasibility of detecting the calcium K absorption line in spectra of sufficient quality. The i-system may represent the QSO host galaxy or a companion. Photoionization requires the black hole to be ~3 kpc from the r-system emitting gas, implying that we are observing the system only 10^6 yr after the recoil event and contributing to the low probability of observing such a system. The HET observations give an upper limit of 10 km/s per year on the rate of change of the velocity difference between the r- and b-systems, constraining the orbital phase in the binary model. These considerations and the presence of a cluster of galaxies apparently containing J0927 favor the idea that this system represents a superposition of two AGN.Comment: 18 pages, 4 figures, ApJ in press, revised discussion of stellar absorption features and binary black hole mode

Oxalis pes-caprae L. (Oxalidaceae), nova vrsta u hrvatskoj flori

This paper reports the first findings of the species Oxalis pes-caprae L. in Croatia. The species was found in the town of Komiža (the island of Vis) in the spring of 2000 as well as on the island of Biševo in the spring of 2001. In both cases plants were found within ruderal vegetation. The species is extensively naturalized in the Mediterranean region and western Europe, but in Croatian flora it comes as an adventitious species.U radu se iznose podaci o prvim nalazima vrste Oxalis pes-caprae L. u Hrvatskoj. Vrsta je nađena u gradu Komiži na otoku Visu u proljeće 2000. godine, te na otoku Biševu u proljeće 2001. godine. Na oba nalazišta biljke su zabilježene unutar ruderalne vegetacije. U Mediteranu i zapadnoj Europi vrsta je uvelike naturalizirana, dok u flori Hrvatske dolazi kao adventivna vrsta

Oxalis pes-caprae L. (Oxalidaceae), nova vrsta u hrvatskoj flori

This paper reports the first findings of the species Oxalis pes-caprae L. in Croatia. The species was found in the town of Komiža (the island of Vis) in the spring of 2000 as well as on the island of Biševo in the spring of 2001. In both cases plants were found within ruderal vegetation. The species is extensively naturalized in the Mediterranean region and western Europe, but in Croatian flora it comes as an adventitious species.U radu se iznose podaci o prvim nalazima vrste Oxalis pes-caprae L. u Hrvatskoj. Vrsta je nađena u gradu Komiži na otoku Visu u proljeće 2000. godine, te na otoku Biševu u proljeće 2001. godine. Na oba nalazišta biljke su zabilježene unutar ruderalne vegetacije. U Mediteranu i zapadnoj Europi vrsta je uvelike naturalizirana, dok u flori Hrvatske dolazi kao adventivna vrsta

The supramolecular arrangement in the Ni(II) complexes of isothiosemicarbazide

The molecules of two complexes [Ni(ITSC)2(H2O)2](tere)·2H2O and [Ni(ITSC)2(NO3)2] (ITSC = S-methylisothiosemicarbazide; tere = terephthalate) tend to associate trough the hydrogen bonding interactions into the characteristic 2D blocks separated by the S-methyl moieties. The different coordination mode of the isothiosemicarbazide comparing to thiosemicarbazide (TSC) prevents the formation of the complementary hydrogen bonds with dicarboxylate important for selfassambly of TSC complexes, however in these ITSC the terephthalate anion has role in connection of the blocks and transformation of the 2D into the 3D supramolecular structure. The similar crystal arrangement is found in two earlier reported complexes of Ni(II) with ITSC.Physical chemistry 2004 : 7th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 21-23 September 200

Sporobolus pungens (Schreber) Kunth (Poaceae), rijetka i ugrožena psamofitska biljna vrsta u Hrvatskoj

Sporobolus pungens (Schreber) Kunth is rare and endangered psammophytic plant species, with four localities in Croatia known to date, all on the central and south Dalmatian islands. In October 2001 a new locality was found on the island of Mljet, in Blaca Bay seashore sands, as a part of the psammo-halophytic community Echinophoro-Elymetum farcti (Ammophilion).Sporobolus pungens (Schreber) Kunth, rijetka i ugrožena psamofitska biljna vrsta, dosad je bila poznata s četiri nalazišta u Hrvatskoj na srednjodalmatinskim i južnodalmatinskim otocima. U mjesecu listopadu 2001. nađeno je novo nalazište na otoku Mljetu, u uvali Blaca, na obalnim pijescima u sastavu psamohalofitske asocijacije Echinophoro-Elymetum farcti (Ammophilion)

Study of C−H⋅⋅⋅π interactions with pyrrole and chelate rings in metal-porphyrin complexes

The Cambridge Structural Database (CSD) was screened in order to find and investigate specific C−H⋅⋅⋅π interactions between C−H groups and two types of rings with delocalized π-bonds that exist in porphyrin: pyrrole and six-membered chelate. Statistical analysis of geometrical parameters for interactions in both types of rings was done. In order to determine preferred positions in porphyrinato ring for C−H⋅⋅⋅π interactions fifteen different points distributed over porphyrin ring have been chosen and each of them have been analyzed. Calculations of these interactions by density functional theory (DFT) have been done on three different model systems.Physical chemistry 2006 : 8th international conference on fundamental and applied aspects of physical chemistry; Belgrade (Serbia); 26-29 September 200

Aligned Spins: Orbital Elements, Decaying Orbits, and Last Stable Circular Orbit to high post-Newtonian Orders

In this article the quasi-Keplerian parameterisation for the case that spins and orbital angular momentum in a compact binary system are aligned or anti-aligned with the orbital angular momentum vector is extended to 3PN point-mass, next-to-next-to-leading order spin-orbit, next-to-next-to-leading order spin(1)-spin(2), and next-to-leading order spin-squared dynamics in the conservative regime. In a further step, we use the expressions for the radiative multipole moments with spin to leading order linear and quadratic in both spins to compute radiation losses of the orbital binding energy and angular momentum. Orbital averaged expressions for the decay of energy and eccentricity are provided. An expression for the last stable circular orbit is given in terms of the angular velocity type variable $x$.Comment: 30 pages, 2 figures, v2: update to match published versio

Intramolecular C-H⋯π interactions in metal-porphyrin complexes

Cambridge Structural Database (CSD) was screened in order to find intramolecular C-H⋯π interactions with a chelate ring of coordinated porphyrin. It was found 154 crystal structures with 244 intramolecular C-H⋯π interactions in transition metal complexes with derivatives of porphyrin. Comparison of interacting distances indicates that interactions of hydrogen atoms in positions 2 and 6 of axially coordinated pyridine are more favorable with ruffled than with planar porphyrin

Magnetothermal instabilities in magnetized anisotropic plasmas

Using the transport equations for an ideal anisotropic collisionless plasma derived from the Vlasov equation by the 16-moment method, we analyse the influence of pressure anisotropy exhibited by collisionless magnetized plasmas on the magnetothermal (MTI) and heat-flux-driven buoyancy (HBI) instabilities. We calculate the dispersion relation and the growth rates for these instabilities in the presence of a background heat flux and for configurations with static pressure anisotropy, finding that when the frequency at which heat conduction acts is much larger than any other frequency in the system (i.e. weak magnetic field) the pressure anisotropy has no effect on the MTI/HBI, provided the degree of anisotropy is small. In contrast, when this ordering of timescales does not apply the instability criteria depend on pressure anisotropy. Specifically, the growth time of the instabilities in the anisotropic case can be almost one order of magnitude smaller than its isotropic counterpart. We conclude that in plasmas where pressure anisotropy is present the MTI/HBI are modified. However, in environments with low magnetic fields and small anisotropy such as the ICM the results obtained from the 16-moment equations under the approximations considered are similar to those obtained from ideal MHD.Comment: v3: 16 pages, 2 figures, fixed typos, added references and a final note on related wor

Sinteza i kristalna struktura 1,2,3,4-tetrahidro-9-aminoakridin-tetrahlorocinkata(II) monohidrata

In the reaction of ZnCl(2) with tacrine hydrochloride in water novel tetracoordinated (C(13)H(15)N(2))(2)[ZnCl(4)]-H(2)O complex was obtained and characterized by elemental analysis, molar conductivity and X-ray analysis. The complex crystallizes in the space group P-1 of the triclinic crystal system. The structure contains two crystallographically different molecules of protonated tacrine present as counter cations, the [ZnCl(4)](2-) complex anion and one water solvent molecule. The counter cations slightly differ in the puckering of the cyclohexene ring. The molecules of protonated tacrine are involved in different intermolecular hydrogen bonds. In the crystal, the hydrogen bonding generates a 3D assembly. In the crystal, pi center dot center dot center dot pi stacking interactions between the rings of protonated tacrine were evidenced. The [ZnCl(4)](2-) complex anion has a distorted tetrahedral geometry. Three out of the four Cl atoms are involved in intermolecular hydrogen bonding. The intermolecular H-bond interactions involving the Cl atoms affect the Zn-CI bond lengths.U reakciji ZnCl2 sa takrin-hidrohloridom u vodi, dobijen je novi tetrakoordinovani (C13H15N2)2[ZnCl4]?H2O kompleks koji je okarakterisan pomoću elementalne analize, molarne provodljivosti i rendgenske strukturne analize. Kompleks kristališe u prostornoj grupi P?1 trikliničnog kristalnog sistema. Struktura sadrži dva kristalografski različita molekula protonovanog takrina koji su prisutni kao kontra-katjoni, [ZnCl4]2 kompleksni anjon i molekul kristalne vode. Molekuli katjona se neznatno razlikuju u stepenu nabiranja cikloheksenovog prstena. Molekuli protonovanog takrina su uključeni u različite intermolekulske vodonične veze. Intermolekulsko vodonično vezivanje u kristalu generiše 3D molekulski skup pi...pi interakcije između prstenova protonovanog takrina su primećene u kristalu. [ZnCl4]2- ima distorgovanu tetraedarsku geometriju. Tri od četiri Cl atoma su uključena u intermolekulske vodonične veze. Intermolekulske vodonične interakcije koje uključuju Cl atome utiču na dužinu Zn-Cl veza