3 research outputs found

    Quasar induced galaxy formation: a new paradigm ?

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    We discuss observational evidence that quasars play a key role in the formation of galaxies starting from the detailed study of the quasar HE0450-2958 and extending the discussion to a series of converging evidence that radio jets may trigger galaxy formation. The direct detection with VISIR at the ESO-VLT of the 7 kpc distant companion galaxy of HE0450-2958 allows us to spatially separate the sites of quasar and star formation activity in this composite system made of two ultra-luminous infrared galaxies (ULIRGs). No host galaxy has yet been detected for this quasar, but the companion galaxy stellar mass would bring HE0450-2958 in the local M(BH)-M(stellar bulge) relation if it were to merge with the QSO. This is bound to happen because of their close distance (7 kpc) and small relative velocity (~60-200 km/s). We conclude that we may be witnessing the building of the M(BH)-M(stellar bulge) relation, or at least of a major event in that process. The star formation rate (~340 Msun/yr), age (40-200 Myr) and stellar mass ([5-6]x10^10 Msun) are consistent with jet-induced formation of the companion galaxy. We suggest that HE0450-2958 may be fueled in fresh material by cold gas accretion from intergalactic filaments. We map the projected galaxy density surrounding the QSO as a potential tracer of intergalactic filaments and discuss a putative detection. Comparison to other systems suggests that inside-out formation of quasar host galaxies and jet-induced galaxy formation may be a common process. Two tests are proposed for this new paradigm: (1) the detection of offset molecular gas or dust emission with respect to the position of distant QSOs, (2) the delayed formation of host galaxies as a result of QSO activity, hence the two step building of the M(BH)/M(stellar bulge) ratio.Comment: 15 pages, 8 figures, accepted for publication in Astronomy and Astrophysics (with minor corrections

    An analysis of Texas\u27s school based HPV vaccine mandate: A public health risk communication failure: HPVETO!

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    Genital human papillomavirus (HPV) is of public health concern because persistent infection with certain HPV types can cause cervical cancer. In response to a nationwide push for cervical cancer legislation, Texas Governor Rick Perry bypassed the traditional legislative process and issued an executive order mandating compulsory HPV vaccinations for all female public school students prior to their entrance in the sixth grade. By bypassing the legislative process Governor Perry did not effectively mitigate the risk perception issues that arose around the need for and usefulness of the vaccine mandate. This policy paper uses a social policy paradigm to identify perception as the key intervening factor on how the public responds to risk information. To demonstrate how the HPV mandate failed, it analyzes four factors, economics, politics, knowledge and culture, that shape perception and influence the public\u27s response. By understanding the factors that influence the public\u27s perception, public health practitioners and policy makers can more effectively create preventive health policy at the state level

    Replication data for: Lesotho (2006): HIV/AIDS TRaC Study among the General Population (15-35 years) First Round

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    In 2006 Population Services International (PSI) Lesotho conducted a household survey designed to investigate consistent condom use and Voluntary Counseling and Testing (for HIV) services uptake for a national sample of 1600 men and women aged between 15-35 years in Lesotho. The 2006 HIV TRaC survey collected information from randomly selected men and women aged between 15-35 years in all the 10 districts of Lesotho. A multi-stage stratified cluster sampling was used which provided a nationally representative sample of 1600 respondents. Data collection was supervised by PSI staff and external enumerators were used. Results of the study are presented in standard PSI dashboard form
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