172 research outputs found

    Understanding extreme quasar optical variability with CRTS:II. Changing-state quasars

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    We present the results of a systematic search for quasars in the Catalina Real-time Transient Survey exhibiting both strong photometric and spectroscopic variability over a decadal baseline. We identify 73 sources with specific patterns of optical and mid-IR photometric behavior and a defined spectroscopic change. These "Changing-State" quasars (CSQs) form a higher luminosity sample to complement existing sets of "Changing-Look" AGN and quasars in the literature. The CSQs (by selection) exhibit larger photometric variability than the CLQs. The spectroscopic variability is marginally stronger in the CSQs than CLQs as defined by the change in Hβ\beta/[OIII] ratio. We find 36 sources with declining Hβ\beta flux, 37 sources with increasing Hβ\beta flux and discover seven sources with z>0.8z > 0.8, further extending the redshift arm. Our CSQ sample compares to the literature CLQ objects in similar distributions of Hβ\beta flux ratios and differential Eddington ratios between high (bright) and low (dim) states. Taken as a whole, we find that this population of extreme varying quasars is associated with changes in the Eddington ratio and the timescales imply cooling/heating fronts propagating through the disk.Comment: 43 pages, 22 figures, submitte

    A Highly Magnified Gravitationally Lensed Red QSO at z = 2.5 with a Significant Flux Ratio Anomaly

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    We present the discovery of a gravitationally lensed dust-reddened QSO at z = 2.517, identified in a survey for QSOs by infrared selection. Hubble Space Telescope imaging reveals a quadruply lensed system in a cusp configuration, with a maximum image separation of ~1.8\arcsec. We find that compared to the central image of the cusp, the neighboring brightest image is anomalous by a factor of ~ 7 - 10, which is the largest flux anomaly measured to date in a lensed QSO. Incorporating high-resolution Jansky Very Large Array radio imaging and sub-mm imaging with the Atacama Large (sub-)Millimetre Array, we conclude that a low-mass perturber is the most likely explanation for the anomaly. The optical through near-infrared spectrum reveals that the QSO is moderately reddened with E(B - V) = 0.7 - 0.9. We see an upturn in the ultraviolet spectrum due to ~ 1% of the intrinsic emission being leaked back into the line of sight, which suggests that the reddening is intrinsic and not due to the lens. The QSO may have an Eddington ratio as high as L/L_Edd ~ 0.2. Consistent with previous red QSO samples, this source exhibits outflows in its spectrum as well as morphological properties suggestive of it being in a merger-driven transitional phase. We find a host-galaxy stellar mass of log M_*/M_Sun = 11.4, which is higher than the local M_BH vs. M_* relation, but consistent with other high redshift QSOs. When de-magnified, this QSO is at the knee of the luminosity function, allowing for the detailed study of a more typical moderate-luminosity infrared-selected QSO at high redshift.Comment: Accepted for publication in ApJ; 29 pages, 18 figures, 8 tables. arXiv admin note: text overlap with arXiv:1807.0543

    Peering through the Dust: NuSTAR Observations of Two FIRST-2MASS Red Quasars

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    Some reddened quasars appear to be transitional objects in the merger-induced black hole growth/galaxy evolution paradigm, where a heavily obscured nucleus starts to be unveiled by powerful quasar winds evacuating the surrounding cocoon of dust and gas. Hard X-ray observations are able to peer through this gas and dust, revealing the properties of circumnuclear obscuration. Here, we present NuSTAR and XMM-Newton/Chandra observations of FIRST-2MASS selected red quasars F2M 0830+3759 and F2M 1227+3214. We find that though F2M 0830+3759 is moderately obscured (N_(H,Z) = 2.1 ± 0.2 × 10^(22) cm^(−2)) and F2M 1227+3214 is mildly absorbed (N_(H,Z) = 3.4^(+0.8)_(−0.7) × 10^(21) cm^(−2)) along the line-of-sight, heavier global obscuration may be present in both sources, with N_(H,S) = 3.7^(+4.1)_(−2.6) × 10^(23) cm^(−2) and < 5.5 × 10^(23) cm^(−2), for F2M 0830+3759 and F2M 1227+3214, respectively. F2M 0830+3759 also has an excess of soft X-ray emission below 1 keV which is well accommodated by a model where 7% of the intrinsic AGN X-ray emission is scattered into the line-of-sight. While F2M 1227+3214 has a dust-to-gas ratio (E(B − V )/N_H) consistent with the Galactic value, the E(B−V )/NH value for F2M 0830+3759 is lower than the Galactic standard, consistent with the paradigm that the dust resides on galactic scales while the X-ray reprocessing gas originates within the dust-sublimation zone of the broad-line-region. The X-ray and 6.1μm luminosities of these red quasars are consistent with the empirical relations derived for high-luminosity, unobscured quasars, extending the parameter space of obscured AGN previously observed by NuSTAR to higher luminosities

    Antiphospholipid Antibodies Bind ATP: A putative Mechanism for the Pathogenesis of Neuronal Dysfunction

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    Antiphospholipid antibodies (aPL) generated in experimental animals cross-react with ATP. We therefore examined the possibility that aPL IgG from human subjects bind to ATP by affinity column and an enzyme linked immunosorbent assay (ELISA). Sera with high levels of aPL IgG were collected from 12 patients with the antiphospholipid syndrome (APS). IgG fractions from 10 of 12 APS patients contained aPL that could be affinity-bound to an ATP column and completely eluted with NaCl 0.5 M. A significant (>50%) inhibition of aPL IgG binding by ATP 5 mM was found in the majority. Similar inhibition was obtained with ADP but not with AMP or cAMP. All the affinity purified anti-ATP antibodies also bound β2-glycoprotein-I (β2-GPI, also known as apolipoprotein H) suggesting that, similar to most pathogenic aPL, their binding depends on this serum cofactor. We further investigated this possibility and found that the binding of β2-GPI to the ATP column was similar to that of aPL IgG in that most was reversed by NaCl 0.5 M. Furthermore, addition of β2-GPI to aPL IgG significantly increased the amount of aPL binding to an ATP column. We conclude that aPL IgG bind ATP, probably through β2-GPI. This binding could interfere with the normal extracellular function of ATP and similar neurotransmitters

    Interferon-inducible gene 202b controls CD8+ T cell-mediated suppression in anti-DNA Ig peptide-treated (NZB × NZW) F1 lupus mice

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    Administration of an artificial peptide (pConsensus) based on anti-DNA IgG sequences that contain major histocompatibility complex class I and class II T-cell determinants, induces immune tolerance in NZB/NZW F1 female (BWF1) mice. To understand the molecular basis of CD8+ Ti-mediated suppression, we previously performed microarray analysis to identify genes that were differentially expressed following tolerance induction with pCons. CD8+ T cells from mice tolerized with pCons showed more than two-fold increase in Ifi202b mRNA, an interferon inducible gene, versus cells from untolerized mice. Ifi202b expression increased through weeks 1–4 after tolerization and then decreased, reapproaching baseline levels at 6 weeks. In vitro polyclonal activation of tolerized CD8+ T cells significantly increased Ifi202b mRNA expression. Importantly, silencing of Ifi202b abrogated the suppressive capacity of CD8+ Ti cells. This was associated with decreased expression of Foxp3, and decreased gene and protein expression of transforming growth factor (TGF)β and interleukin-2 (IL-2), but not of interferon (IFN)-γ, IL-10, or IL-17. Silencing of another IFN-induced gene upregulated in tolerized CD8+ T cells, IFNAR1, had no effect on the ability of CD8+ T cells to suppress autoantibody production. Our findings indicate a potential role for Ifi202b in the suppressive capacity of peptide-induced regulatory CD8+ Ti cells through effects on the expression of Foxp3 and the synthesis of TGFβ

    The 2003 Australian Breast Health Survey: survey design and preliminary results

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    <p>Abstract</p> <p>Background</p> <p>The Breast Health Surveys, conducted by the National Breast Cancer Centre (NBCC) in 1996 and 2003, are designed to gain insight into the knowledge, attitudes and behaviours of a nationally representative sample of Australian women on issues relevant to breast cancer. In this article, we focus on major aspects of the design and present results on respondents' knowledge about mammographic screening.</p> <p>Methods</p> <p>The 2003 BHS surveyed English-speaking Australian women aged 30–69 without a history of breast cancer using computer-assisted telephone interviewing. Questions covered the following themes: knowledge and perceptions about incidence, mortality and risk; knowledge and behaviour regarding early detection, symptoms and diagnosis; mammographic screening; treatment; and accessibility and availability of information and services. Respondents were selected using a complex sample design involving stratification. Sample weights against Australian population benchmarks were used in all statistical analyses. Means and proportions for the entire population and by age group and area of residence were calculated. Statistical tests were conducted using a level of significance of 0.01.</p> <p>Results</p> <p>Of the 3,144 respondents who consented to being interviewed, 138 (4.4%) had a previous diagnosis of breast cancer and were excluded leaving 3,006 completed interviews eligible for analysis. A majority of respondents (61.1%) reported ever having had a mammogram and 29.1% identified mammography as being the best way of finding breast cancer. A majority of women (85.9%) had heard of the BreastScreen Australia (BSA) program, the national mammographic screening program providing free biennial screening mammograms, with 94.5% believing that BSA attendance was available regardless of the presence or absence of symptoms. There have been substantial gains in women's knowledge about mammographic screening over the seven years between the two surveys.</p> <p>Conclusion</p> <p>The NBCC Breast Health Surveys provide a valuable picture of the knowledge of Australian women about a range of issues. The present analysis shows significant gains in knowledge and behaviours relating to mammographic screening, while identifying additional areas for targeted improvement, as in the need to better communicate with women about screening and diagnostic services. Further analysis of additional core topic areas (eg., incidence, mortality, risk and treatment) will provide equally noteworthy insight.</p

    La experiencia religiosa desde el proceso formativo en ciencias religiosas virtual: en el caso de Karollay Carreño Colina

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    La técnica del relato autobiográfico permite que la experiencia religiosa al ser relatada y compartida no se pierda, ya que esta experiencia humana se adquiere a través de los hechos y vivencias que suceden en la vida del sujeto, en donde la experiencia religiosa se va estructurando como la posibilidad de hacer consiente y manifiesto ese vínculo correlacional con el ser transcendente que es Dios. Tomando el enfoque cualitativo, cuyo estudio es necesariamente la persona y su contexto y la narrativa autobiográfica, lo que se busca en este trabajo, es entrever cómo se vive la experiencia religiosa en el proceso formativo en las aulas virtuales de aprendizaje y cómo ésta se hace consciente en cada persona desde su propio proceso de fe en los AVA De esta manera se inicia la interpretación hermenéutica teológica del relato autobiográfico de la experiencia religiosa en el proceso formativo en la Licenciatura en Ciencias Religiosas Virtual, describiendo los momentos existenciales y formativos que han favorecido el acontecer de dicha experiencia, evidenciando que ésta es una realidad que se vive dentro de la virtualidad, ya que en muchos momentos se piensa que los ambientes virtuales de aprendizaje AVA, son lugares fríos, mediados por las tecnologías, en donde la experiencia religiosa no puede llegar a trasmitirse, pero estos son lugares en donde realmente se pueden tener experiencias religiosas realmente significativas, requiriendo una atención muy especial para comprender que tras el ambiente virtual, hay y se pueden dar nuevas formas de vivir la religión y la espiritualidad, por ello tan importante el relato autobiográfico. Conforme a lo anterior, se puede evidenciar la experiencia humana como lugar donde acontece la experiencia de Dios, convirtiéndose así el relato autobiográfico en una técnica o camino donde se expresa dicha experiencia y donde los ambientes virtuales de aprendizaje AVA, se articulan como nuevos contextos donde dicha experiencia debe hacerse actual, para contribuir a procesos de formación integral permanente de estudiantes y docentes en la licenciatura en Ciencias Religiosas. Ahora bien, todas las personas tienen historias que contar, que al biografiarlas, se convierten en autores de su propio relato, en donde ponen de manifiesto no solo sus vidas, sino también aquello que los caracteriza, al tiempo que se convierte en un medio para transmitir la experiencia religiosa. Autorelatarse supone entonces compartir la vida y es que la experiencia humana nace en lo profundo del ser, en esa la relación de encuentro con quien le trasciende.An autobiographical storytelling technique allows a religious experience to be told and shared, Keeping it alive since, this human experience is achieved through personal life lessons that every human being has. So, this religious experience is put together to build up the possibility to be conscious about the correlational tie with God and put it forth. From a qualitative approach, which necessary focuses on the person and his/her context and the autobiographical narrative, what this paper looks for is to see how the religious experience is lived in Virtual Training Rooms learning processes, how every person, from their personal procedure, gets conscious about their own faith process. This way, the theological hermeneutics interpretation of religious autobiographical experiences in the Virtual Religious Science Degree is introduced, describing existential and educational moments that have favored these experiences, showing the reality lived from virtuality, considering that these virtual learning environment (VLE) are indifferent and influenced by technologies, where religious experiences cannot be transmitted, although these places are where you can really have a significant religious experience, it is required a special attention to understand that, behind a virtual circle there are new ways to experience religion and spirituality, that is why autobiographical stories are so relevant. In agreement on what is expressed above, it is evident that the human experience, as a space to experience God, has turned the autobiographical storytelling into a technique or way to express it, where virtual learning environment (VLE) are assembled like new context where that experience must be current to contribute on students and Religious Science teachers comprehensive and permanent training process. Having said that, everyone of us has stories to tell so, who write them turn into their own storytellers, where their lives express not only what they have gone through but what typifies them, at the same time these expressions become the means to share religious experiences. To tell your own story supposes that sharing life is a human experience that was boom at the bottom of your inner self, stemming from convergence and transcendence.Licenciado (a) en Ciencias ReligiosasPregrad
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