755 research outputs found

    The Lick AGN Monitoring Project 2011: Dynamical Modeling of the Broad Line Region in Mrk 50

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    We present dynamical modeling of the broad line region (BLR) in the Seyfert 1 galaxy Mrk 50 using reverberation mapping data taken as part of the Lick AGN Monitoring Project (LAMP) 2011. We model the reverberation mapping data directly, constraining the geometry and kinematics of the BLR, as well as deriving a black hole mass estimate that does not depend on a normalizing factor or virial coefficient. We find that the geometry of the BLR in Mrk 50 is a nearly face-on thick disk, with a mean radius of 9.6(+1.2,-0.9) light days, a width of the BLR of 6.9(+1.2,-1.1) light days, and a disk opening angle of 25\pm10 degrees above the plane. We also constrain the inclination angle to be 9(+7,-5) degrees, close to face-on. Finally, the black hole mass of Mrk 50 is inferred to be log10(M(BH)/Msun) = 7.57(+0.44,-0.27). By comparison to the virial black hole mass estimate from traditional reverberation mapping analysis, we find the normalizing constant (virial coefficient) to be log10(f) = 0.78(+0.44,-0.27), consistent with the commonly adopted mean value of 0.74 based on aligning the M(BH)-{\sigma}* relation for AGN and quiescent galaxies. While our dynamical model includes the possibility of a net inflow or outflow in the BLR, we cannot distinguish between these two scenarios.Comment: Accepted for publication in ApJ. 8 pages, 6 figure

    Seasonal changes in patterns of gene expression in avian song control brain regions.

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    This is an open-access article distributed under the terms of the Creative Commons Attribution License, which permits unrestricted use, distribution, and reproduction in any medium, provided the original author and source are credited.Photoperiod and hormonal cues drive dramatic seasonal changes in structure and function of the avian song control system. Little is known, however, about the patterns of gene expression associated with seasonal changes. Here we address this issue by altering the hormonal and photoperiodic conditions in seasonally-breeding Gambel's white-crowned sparrows and extracting RNA from the telencephalic song control nuclei HVC and RA across multiple time points that capture different stages of growth and regression. We chose HVC and RA because while both nuclei change in volume across seasons, the cellular mechanisms underlying these changes differ. We thus hypothesized that different genes would be expressed between HVC and RA. We tested this by using the extracted RNA to perform a cDNA microarray hybridization developed by the SoNG initiative. We then validated these results using qRT-PCR. We found that 363 genes varied by more than 1.5 fold (>log(2) 0.585) in expression in HVC and/or RA. Supporting our hypothesis, only 59 of these 363 genes were found to vary in both nuclei, while 132 gene expression changes were HVC specific and 172 were RA specific. We then assigned many of these genes to functional categories relevant to the different mechanisms underlying seasonal change in HVC and RA, including neurogenesis, apoptosis, cell growth, dendrite arborization and axonal growth, angiogenesis, endocrinology, growth factors, and electrophysiology. This revealed categorical differences in the kinds of genes regulated in HVC and RA. These results show that different molecular programs underlie seasonal changes in HVC and RA, and that gene expression is time specific across different reproductive conditions. Our results provide insights into the complex molecular pathways that underlie adult neural plasticity

    The Lick AGN Monitoring Project: Recalibrating Single-Epoch Virial Black Hole Mass Estimates

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    We investigate the calibration and uncertainties of black hole mass estimates based on the single-epoch (SE) method, using homogeneous and high-quality multi-epoch spectra obtained by the Lick Active Galactic Nucleus (AGN) Monitoring Project for 9 local Seyfert 1 galaxies with black hole masses < 10^8 M_sun. By decomposing the spectra into their AGN and stellar components, we study the variability of the single-epoch Hbeta line width (full width at half-maximum intensity, FWHM_Hbeta; or dispersion, sigma_Hbeta) and of the AGN continuum luminosity at 5100A (L_5100). From the distribution of the "virial products" (~ FWHM_Hbeta^2 L_5100^0.5 or sigma_Hbeta^2 L_5100^0.5) measured from SE spectra, we estimate the uncertainty due to the combined variability as ~ 0.05 dex (12%). This is subdominant with respect to the total uncertainty in SE mass estimates, which is dominated by uncertainties in the size-luminosity relation and virial coefficient, and is estimated to be ~ 0.46 dex (factor of ~ 3). By comparing the Hbeta line profile of the SE, mean, and root-mean-square (rms) spectra, we find that the Hbeta line is broader in the mean (and SE) spectra than in the rms spectra by ~ 0.1 dex (25%) for our sample with FWHM_Hbeta < 3000 km/s. This result is at variance with larger mass black holes where the difference is typically found to be much less than 0.1 dex. To correct for this systematic difference of the Hbeta line profile, we introduce a line-width dependent virial factor, resulting in a recalibration of SE black hole mass estimators for low-mass AGNs.Comment: Accepted for publication in ApJ. 18 pages, 17 figure

    Characterization of gene mutations and copy number changes in acute myeloid leukemia using a rapid target enrichment protocol

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    Prognostic stratification is critical for making therapeutic decisions and maximizing survival of patients with acute myeloid leukemia. Advances in the genomics of acute myeloid leukemia have identified several recurrent gene mutations whose prognostic impact is being deciphered. We used HaloPlex target enrichment and Illumina-based next generation sequencing to study 24 recurrently mutated genes in 42 samples of acute myeloid leukemia with a normal karyotype. Read depth varied between and within genes for the same sample, but was predictable and highly consistent across samples. Consequently, we were able to detect copy number changes, such as an interstitial deletion of BCOR, three MLL partial tandem duplications, and a novel KRAS amplification. With regards to coding mutations, we identified likely oncogenic variants in 41 of 42 samples. NPM1 mutations were the most frequent, followed by FLT3, DNMT3A and TET2. NPM1 and FLT3 indels were reported with good efficiency. We also showed that DNMT3A mutations can persist post-chemotherapy and in 2 cases studied at diagnosis and relapse, we were able to delineate the dynamics of tumor evolution and give insights into order of acquisition of variants. HaloPlex is a quick and reliable target enrichment method that can aid diagnosis and prognostic stratification of acute myeloid leukemia patients.This project was funded by the Wellcome Trust. NB is a fellow of the European Hematology Association and was supported by the Academy of Medical Sciences. EP is a European Hematology Association Advanced Research Fellow. GV is a Wellcome Trust Senior Fellow in Clinical Science. IV is funded by Spanish Ministerio de Economía y Competitividad subprograma Ramón y Cajal

    Menthol Cigarette Smoking and Obesity in Young Adult Daily Smokers in Hawaii

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    This study investigates 1) the relationship between menthol cigarette smoking and obesity and 2) the association of body mass index with the nicotine metabolite ratio among menthol and non-menthol daily smokers aged 18–35 (n = 175). A brief survey on smoking and measures of height and weight, carbon monoxide, and saliva samples were collected from participants from May to December 2013 in Honolulu, Hawaii. Multiple regression was used to estimate differences in body mass index among menthol and non-menthol smokers and the association of menthol smoking with obesity. We calculated the log of the nicotine metabolite ratio to examine differences in the nicotine metabolite ratio among normal, overweight, and obese smokers. Sixty-eight percent of smokers used menthol cigarettes. Results showed that 62% of normal, 54% of overweight, and 91% of obese smokers used menthol cigarettes (p = .000). The mean body mass index was significantly higher among menthol compared with non-menthol smokers (29.4 versus 24.5, p = .000). After controlling for gender, marital status, educational attainment, employment status, and race/ethnicity, menthol smokers were more than 3 times as likely as non-menthol smokers to be obese (p = .04). The nicotine metabolite ratio was significantly lower for overweight menthol smokers compared with non-menthol smokers (.16 versus .26, p = .02) in the unadjusted model, but was not significant after adjusting for the covariates. Consistent with prior studies, our data show that menthol smokers are more likely to be obese compared with non-menthol smokers. Future studies are needed to determine how flavored tobacco products influence obesity among smokers

    Fine-mapping identifies multiple prostate cancer risk loci at 5p15, one of which associates with TERT expression

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    Associations between single nucleotide polymorphisms (SNPs) at 5p15 and multiple cancer types have been reported. We have previously shown evidence for a strong association between prostate cancer (PrCa) risk and rs2242652 at 5p15, intronic in the telomerase reverse transcriptase (TERT) gene that encodes TERT. To comprehensively evaluate the association between genetic variation across this region and PrCa, we performed a fine-mapping analysis by genotyping 134 SNPs using a custom Illumina iSelect array or Sequenom MassArray iPlex, followed by imputation of 1094 SNPs in 22 301 PrCa cases and 22 320 controls in The PRACTICAL consortium. Multiple stepwise logistic regression analysis identified four signals in the promoter or intronic regions of TERT that independently associated with PrCa risk. Gene expression analysis of normal prostate tissue showed evidence that SNPs within one of these regions also associated with TERT expression, providing a potential mechanism for predisposition to disease
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