479 research outputs found

    Orphan Train Myths and Legal Reality

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    Spectral Energy Distributions and Multiwavelength Selection of Type 1 Quasars

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    We present an analysis of the mid-infrared (MIR) and optical properties of type 1 (broad-line) quasars detected by the Spitzer Space Telescope. The MIR color-redshift relation is characterized to z ~ 3, with predictions to z = 7. We demonstrate how combining MIR and optical colors can yield even more efficient selection of active galactic nuclei (AGNs) than MIR or optical colors alone. Composite spectral energy distributions (SEDs) are constructed for 259 quasars with both Sloan Digital Sky Survey and Spitzer photometry, supplemented by near-IR, GALEX, VLA, and ROSAT data, where available. We discuss how the spectral diversity of quasars influences the determination of bolometric luminosities and accretion rates; assuming the mean SED can lead to errors as large as 50% for individual quasars when inferring a bolometric luminosity from an optical luminosity. Finally, we show that careful consideration of the shape of the mean quasar SED and its redshift dependence leads to a lower estimate of the fraction of reddened/obscured AGNs missed by optical surveys as compared to estimates derived from a single mean MIR to optical flux ratio

    Behavioral and neuroanatomical consequences of cell-type specific loss of dopamine D2 receptors in the mouse cerebral cortex

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    Developmental dysregulation of dopamine D2 receptors (D2Rs) alters neuronal migration, differentiation, and behavior and contributes to the psychopathology of neurological and psychiatric disorders. The current study is aimed at identifying how cell-specific loss of D2Rs in the cerebral cortex may impact neurobehavioral and cellular development, in order to better understand the roles of this receptor in cortical circuit formation and brain disorders. We deleted D2R from developing cortical GABAergic interneurons (Nkx2.1-Cre) or from developing telencephalic glutamatergic neurons (Emx1-Cre). Conditional knockouts (cKO) from both lines, Drd2fl/fl, Nkx2.1-Cre+ (referred to as GABA-D2R-cKO mice) or Drd2fl/fl, Emx1-Cre+ (referred to as Glu-D2R-cKO mice), exhibited no differences in simple tests of anxiety-related or depression-related behaviors, or spatial or nonspatial working memory. Both GABA-D2R-cKO and Glu-D2R-cKO mice also had normal basal locomotor activity, but GABA-D2R-cKO mice expressed blunted locomotor responses to the psychotomimetic drug MK-801. GABA-D2R-cKO mice exhibited improved motor coordination on a rotarod whereas Glu-D2R-cKO mice were normal. GABA-D2R-cKO mice also exhibited spatial learning deficits without changes in reversal learning on a Barnes maze. At the cellular level, we observed an increase in PV+ cells in the frontal cortex of GABA-D2R-cKO mice and no noticeable changes in Glu-D2R-cKO mice. These data point toward unique and distinct roles for D2Rs within excitatory and inhibitory neurons in the regulation of behavior and interneuron development, and suggest that location-biased D2R pharmacology may be clinically advantageous to achieve higher efficacy and help avoid unwanted effects.Fil: Lee, Gloria S.. Florida State University; Estados UnidosFil: Graham, Devon L.. Florida State University; Estados UnidosFil: Noble, Brenda L.. Florida State University; Estados UnidosFil: Trammell, Taylor S.. Florida State University; Estados UnidosFil: McCarthy, Deirdre M.. Florida State University; Estados UnidosFil: Anderson, Lisa R.. Florida State University; Estados UnidosFil: Rubinstein, Marcelo. Consejo Nacional de Investigaciones Científicas y Técnicas. Instituto de Investigaciones en Ingeniería Genética y Biología Molecular "Dr. Héctor N. Torres"; ArgentinaFil: Bhide, Pradeep G.. Florida State University; Estados UnidosFil: Stanwood, Gregg D.. Florida State University; Estados Unido

    Coronavirus infection and PARP expression dysregulate the NAD metabolome: An actionable component of innate immunity

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    Poly(ADP-ribose) polymerase (PARP) superfamily members covalently link either a single ADP-ribose (ADPR) or a chain of ADPR units to proteins using NAD as the source of ADPR. Although the well-known poly(ADP-ribosylating) (PARylating) PARPs primarily function in the DNA damage response, many noncanonical mono(ADP-ribosylating) (MARylating) PARPs are associated with cellular antiviral responses. We recently demonstrated robust up-regulation of several PARPs following infection with murine hepatitis virus (MHV), a model coronavirus. Here we show that SARS-CoV-2 infection strikingly up-regulates MARylating PARPs and induces the expression of genes encoding enzymes for salvage NAD synthesis from nicotinamide (NAM) and nicotinamide riboside (NR), while down-regulating other NAD biosynthetic pathways. We show that overexpression of PARP10 is sufficient to depress cellular NAD and that the activities of the transcriptionally induced enzymes PARP7, PARP10, PARP12 and PARP14 are limited by cellular NAD and can be enhanced by pharmacological activation of NAD synthesis. We further demonstrate that infection with MHV induces a severe attack on host cell NAD+ and NADP+. Finally, we show that NAMPT activation, NAM, and NR dramatically decrease the replication of an MHV that is sensitive to PARP activity. These data suggest that the antiviral activities of noncanonical PARP isozyme activities are limited by the availability of NAD and that nutritional and pharmacological interventions to enhance NAD levels may boost innate immunity to coronaviruses

    Resonant X-Ray Scattering from CeB6_{6}

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    We calculate the resonant x-ray scattering (RXS) spectra near the Ce LIIIL_{\rm III} absorption edge in CeB6_6, on the basis of a microscopic model that the 4f4f states of Ce are atomic while the 5d5d states form an energy band with a reasonable density of states. In the initial state, we employ an effective Hamiltonian of Shiina {\it et al}. in the antiferro-quadrupole (AFQ) ordering phase, while we construct the wave function consistent with the neutron scattering experiment in the magnetic ground state. In the intermediate state, we take full account of the intra-atomic Coulomb interaction. Without assuming any lattice distortion, we obtain sufficient RXS intensities on the AFQ superlattice spot. We obtain the spectral shape, the temperature and magnetic field dependences in good agreement with the experiment, thus demonstrating the mechanism that the intensity is brought about by the modulation of 5d5d states through the anisotropic term of the 5d5d-4f4f Coulomb interaction. In the magnetic ground state, a small pre-edge peak is found by the E2E_2 process. On the magnetic superlattice spot, we get a finite but considerably small intensity. The magnetic form factor is briefly discussed.Comment: Latex, 10 pages, 12 figures. To be published in J. Phys. Soc. Jpn., Vol.71, No. 7 (2002

    HST NICMOS Observations of the Polarization of NGC 1068

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    We have observed the polarized light at 2 micron in the center of NGC 1068 with HST NICMOS Camera 2. The nucleus is dominated by a bright, unresolved source, polarized at a level of 6.0 pm 1.2% with a position angle of 122degr pm 1.5degr. There are two polarized lobes extending up to 8'' northeast and southwest of the nucleus. The polarized flux in both lobes is quite clumpy, with the maximum polarization occurring in the southwest lobe at a level of 17% when smoothed to 0.23'' resolution. The perpendiculars to the polarization vectors in these two lobes point back to the intense unresolved nuclear source to within one 0.076'' Camera 2 pixel, thereby confirming that this is the illuminating source of the scattered light and therefore the probable AGN central engine. Whereas the polarization of the nucleus is probably caused by dichroic absorption, the polarization in the lobes is almost certainly caused by scattering, with very little contribution from dichroic absorption. Features in the polarized lobes include a gap at a distance of about 1'' from the nucleus toward the southwest lobe and a ``knot'' of emission about 5'' northeast of the nucleus. Both features had been discussed by ground-based observers, but they are much better defined with the high spatial resolution of NICMOS. The northeast knot may be the side of a molecular cloud that is facing the nucleus, which cloud may be preventing the expansion of the northeast radio lobe at the head of the radio synchrotron-radiation-emitting jet. We also report the presence of two ghosts in the Camera 2 polarizers. These had not been detected previously (Hines et al. 2000) because they are relatively faint and require observations of a source with a large dynamic range.Comment: 17 pages, 4 figure
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