317 research outputs found

    Impact of Scale Dependent Bias and Nonlinear Structure Growth on the ISW Effect: Angular Power Spectra

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    We investigate the impact of nonlinear evolution of the gravitational potentials in the LCDM model on the Integrated Sachs-Wolfe (ISW) contribution to the CMB temperature power spectrum, and on the cross-power spectrum of the CMB and a set of biased tracers of the mass. We use an ensemble of N-body simulations to directly follow the potentials and compare results to perturbation theory (PT). The predictions from PT match the results to high precision for k<0.2 h/Mpc. We compute the nonlinear corrections to the angular power spectrum and find them to be <10% of linear theory for l<100. These corrections are swamped by cosmic variance. On scales l>100 the departures are more significant, however the CMB signal is more than a factor 10^3 larger at this scale. Nonlinear ISW effects therefore play no role in shaping the CMB power spectrum for l<1500. We analyze the CMB--density tracer cross-spectrum using simulations and renormalized bias PT, and find good agreement. The usual assumption is that nonlinear evolution enhances the growth of structure and counteracts linear ISW on small scales, leading to a change in sign of the CMB-LSS cross-spectrum at small scales. However, PT analysis suggests that this trend reverses at late times when the logarithmic growth rate f(a)=dlnD/dlna<0.5 or om_m(a)<0.3. Numerical results confirm these expectations and we find no sign change in ISW-LSS cross-power for low redshifts. Corrections due to nonlinearity and scale dependence of the bias are found to be <10% for l<100, therefore below the S/N of the current and future measurements. Finally, we estimate the CMB--halo cross-correlation coefficient and show that it can be made to match that for CMB--dark matter to within 5% for thin redshift shells, mitigating the need to model bias evolution.Comment: 27 pages, 19 figure. Hi-res. version: http://www.itp.uzh.ch/~res/NonlinearISW.HiRes.pd

    7-Chloro-4-[(E)-2-(2-methoxy­benzyl­idene)hydrazin-1-yl]quinoline monohydrate

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    In the title hydrate, C17H14ClN3O·H2O, the dihedral angle between the quinoline fused-ring system and the benzene ring is 13.4 (2)° and the conformation about the C=N bond is E. In the crystal, Nh—H⋯Ow and Ow—H⋯Nq (h = hydro­zone, w = water and q = quinoline) hydrogen bonds generate a two-dimenstional network in the ac plane. A weak C—H⋯O inter­action helps to consolidate the packing

    4-[(E)-2-(2-Chloro­benzyl­idene)hydrazin-1-yl]quinolin-1-ium chloride dihydrate

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    In the title hydrated salt, C16H13ClN3 +·Cl−·2H2O, a small twist is evident in the cation so that the chloro­benzene ring is not coplanar with the central hydrazinyl group [the N—C—C—C torsion angle = −4.8 (12)°]. The conformation about the imine N=C bond [1.284 (10) Å] is E. The components of the structure are connected into a three-dimensional architecture via O—H⋯O, O—H⋯Cl and N—H⋯Cl hydrogen bonds. One water H atom is disposed over two sites of equal occupancy

    Different weak interactions in the crystals of three isomeric (E)-N-methyl-N0-(nitrobenzylidene)- 2-(thiophen-2-yl)acetohydrazides

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    We thank the EPSRC National Crystallography Service (University of Southampton) for X-ray data collection.Peer reviewedPublisher PD

    2-{1-[2,8-Bis(trifluoro­meth­yl)quinolin-4-yl]-3,5,6,7,8,8a-hexa­hydro-1H-1,3-oxazolo[3,4-a]pyridin-3-yl}phenol

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    In the title mefloquine–oxazolidine derivative, C24H20F6N2O2, the oxazoline ring adopts an envelope conformation (the flap atom is N) and the piperidine ring has a chair conformation. The oxazoline and benzene residues lie away from the C6 ring of the quinoline group and, to a first approximation, to one side of the plane through the ten atoms (r.m.s. deviation = 0.025 Å). An intra­molecular O—H⋯N(piperidine) hydrogen bond is present. The crystal packing features C—H⋯O, C—H⋯F and C—H⋯π(hy­droxy­benzene) inter­actions

    Mefloquine–oxazolidine derivatives, derived from mefloquine and arenecarbaldehydes: In vitro activity including against the multidrug-resistant tuberculosis strain T113

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    AbstractTen new mefloquine–oxazolidine derivatives, 4-[(1S,8aR)-3-(aryl)hexahydro[1,3]oxazolo[3,4-a]pyridin-1-yl]-2,8-bis(trifluoromethyl)quinoline (1: aryl=substituted phenyl) and 4-[(1S,8aR)-3-(heteroaryl)hexahydro[1,3]oxazolo[3,4-a]pyridin-1-yl]-2,8-bis(trifluoromethyl)quinoline [2: heteroaryl=5-nitrothien-2-yl (2a); 5-nitrofuran-2-yl (2b) and 4H-imidazol-2-yl) (2c)], have been synthesized and evaluated against Mycobacterium tuberculosis. Compounds 1f (aryl=3-ethoxyphenyl), 1g (Ar=3,4,5-(MeO)3-C6H2) and 2c were slightly more active than mefloquine (MIC=33μM) with MICs=24.5, 22.5 and 27.4, respectively, whereas compounds 1e (aryl=3,4-(MeO)2-C6H3) and 2a (MICs=11.9 and 12.1μM, respectively) were ca. 2.7 times more active than mefloquine, with a better tuberculostatic activity than the first line tuberculostatic agent ethambutol (MIC=15.9). The compounds were also assayed against the MDR strain T113 and the same MICs were observed. Thus the new derivatives have advantages over such anti-TB drugs as isoniazid, rifampicin, ethambutol and ofloxacin, for which this strain is resistant. The most active compounds were not cytotoxic to Murine Macrophages Cells in a concentration near their MIC values

    Flowers from Kalanchoe pinnata are a Rich Source of T Cell-Suppressive Flavonoids:

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    The chemical composition and immunosuppressive potential of the flowers from Kalanchoe pinnata (Crassulaceae) were investigated. We found that the aqueous flower extract was more active than the leaf extract in inhibiting murine T cell mitogenesis in vitro. Flavonoids isolated from the flower extract were identified and quantitated based on NMR and HPLC-DAD-MS analysis, respectively. Along with quercetin, four quercetin glycosyl conjugates were obtained, including quercetin 3-O-β-D-glucuronopyranoside and quercetin 3-O-β-D-glucopyranoside, which are described for the first time in K. pinnata. All flavonoids inhibited murine T cell mitogenesis and IL-2 and IL-4 production without cell toxicity. This is the first report on the pharmacological activity of flowers of a Kalanchoe species, which are not used for curative purposes. Our findings show that K. pinnata flowers are a rich source of T-suppressive flavonoids that may be therapeutically useful against inflammatory diseases

    Cosmological consequences of particle creation during inflation

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    Particle creation during inflation is considered. It could be important for species whose interaction is of gravitational strength or weaker. A complete but economical formalism is given for spin-zero and spin-half particles, and the particle abundance is estimated on the assumption that the particle mass in the early universe is of order the Hubble parameter HH. It is roughly the same for both spins, and it is argued that the same estimate should hold for higher spin particles in particular the gravitino. The abundance is bigger than that from the usual particle collision mechanism if the inflationary energy scale is of order 1016GeV10^{16} GeV, but not if it is much lower.Comment: 17 pages, no Figure
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