18 research outputs found
The Asiago-ESO/RASS QSO Survey. III. Clustering analysis and its theoretical interpretation
This is the third paper of a series describing the Asiago-ESO/RASS QSO survey
(AERQS), a project aimed at the construction of an all-sky statistically
well-defined sample of relatively bright QSOs (B<15) at z<0.3. We present here
the clustering analysis of the full spectroscopically identified database (392
AGN). The clustering signal at 0.02<z<0.22 is detected at a 3-4 sigma level and
its amplitude is measured to be r_0=8.6\pm 2.0 h^{-1} Mpc (in a LambdaCDM
model). The comparison with other classes of objects shows that low-redshift
QSOs are clustered in a similar way to Radio Galaxies, EROs and early-type
galaxies in general, although with a marginally smaller amplitude. The
comparison with recent results from the 2QZ shows that the correlation function
of QSOs is constant in redshift or marginally increasing toward low redshift.
We discuss this behavior with physically motivated models, deriving interesting
constraints on the typical mass of the dark matter halos hosting QSOs, M_DMH=
10^{12.7} h^{-1} M_sun (10^{12.0}-10^{13.5}h^{-1} M_sun at 1 sigma confidence
level). Finally, we use the clustering data to infer the physical properties of
local AGN, obtaining M_BH=2 10^8 h^{-1} M_sun (10^7-3 10^9 h^{-1} M_sun) for
the mass of the active black holes, tau_{AGN}= 8 10^6 yr (2 10^{6}-5 10^{7} yr)
for their life-time and eta = 0.14 for their efficiency (always for a LambdaCDM
model).Comment: 37 pages, Astronomical Journal in press. Changes to match the referee
comment
Asymptomatic primary infection with Epstein-Barr virus: observations on young adult cases
Epstein-Barr virus (EBV) is typically acquired asymptomatically in childhood. By contrast, infection later in life often leads to infectious mononucleosis (IM), a febrile illness characterised by anti-EBV IgM antibody-positivity, high loads of circulating latently-infected B cells, and a marked lymphocytosis caused by hyper-expansion of EBV-specific CD8+ T cells plus milder expansion of CD56dim NKG2A+ KIR– NK cells. How the two situations compare is unclear due to the paucity of studies on clinically-silent infection. Here we describe five prospectively-studied asymptomatic infections identified in a sero-epidemiological survey of University entrants. In each case the key blood sample had high cell-associated viral loads without marked IM-like CD8 lymphocytosis or NK cell disturbance. Two of the highest viral load cases showed a coincident expansion of activated EBV-specific CD8+ T cells but overall CD8+ T cell numbers were either unaffected or only mildly increased. Two slightly lower load cases, which serology suggests may have been caught earlier in the course of infection, also showed no T or NK cell expansion at the time. Interestingly, in another higher load case where T and NK cell responses were undetectable in the primary infection bleed, EBV-specific T cell responses did not appear until several months later, by which time virus loads in the blood had already fallen. Thus some asymptomatic primary infections have very high circulating viral loads and a cell-mediated immune response that is qualitatively similar to IM but of lower magnitude. However, others may be quite different and ultimately could reveal novel mechanisms of host control
Detecting the Highest Redshift (z > 8) QSOs in a Wide, Near Infrared Slitless Spectroscopic Survey
We investigate the prospects of extending observations of high redshift QSOs
to z>8 by means of a very wide-area near-infrared slitless spectroscopic
survey, e.g. the planned survey with the European Space Agency's Euclid
telescope. For any QSOs at z>8.06 the strong Lyman-alpha line will enter the
wavelength range of the Euclid near-infrared spectrometer and imaging
photometer (NISP). We perform a detailed simulation of Euclid NISP slitless
spectroscopy (with the parameters of the wide survey) in an artificial field
containing QSO spectra at all redshifts up to z=12. The simulation spectra are
analysed with an automated redshift finder, and a detection rate estimated as a
function of H magnitude and redshift. Spectroscopic identification of QSOs
would reach deeper limits for the redshift ranges where either H-alpha
(0.678.06) is visible. Furthermore, if
photometrically-selected z>8 spectra can be re-examined and re-fitted to
minimize the effects of spectral contamination, the QSO detection rate in the
Lyman-alpha window will be increased by an estimated 60% and will then be
better here than at any other redshift, with an effective limit H=21.5. With an
extrapolated rate of QSO evolution, we predict the Euclid wide (15000 sq. deg.)
spectroscopic survey will identify 20-35 (19-33 with a small correction for
lineless objects) very luminous QSOs at z>8.06.Comment: 16 pages, 19 figures, accepted for publication in MNRA
4MOST : the 4-metre multi-object spectroscopic telescope project in the assembly, integration, and test phase
4MOST is a new high-multiplex, wide-field spectroscopic survey facility under construction for ESO's 4m-VISTA telescope at Paranal, Chile. Its key specifications are: a large field of view of 4.4 square degrees, a high multiplex fibre positioner based on the tilting spine principle that positions 2436 science fibres in the focal surface of which 1624 fibres go to two low-resolution optical spectrographs (R = λ/Δλ ~ 6500) and 812 fibres transfer light to the high-resolution optical spectrograph (R ~ 20,000). Currently, almost all subsystems are completed and full testing in Europe will be finished in spring 2023, after which 4MOST will be shipped to Chile. An overview is given of instrument construction and capabilities, the planned science of the consortium and the recently selected community programmes, and the unique operational scheme of 4MOST
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Associations of parent-adolescent relationship quality with type 1 diabetes management and depressive symptoms in Latino and Caucasian youth.
ObjectiveTo examine associations of parent-adolescent relationship quality (parental acceptance and parent-adolescent conflict) with adolescent type 1 diabetes management (adherence and metabolic control) and depressive symptoms in Latinos and Caucasians.MethodsIn all, 118 adolescents and their mothers (56 = Latino, 62 = Caucasian) completed survey measures of parental acceptance, diabetes conflict, adolescent adherence, and adolescent depressive symptoms. Glycemic control was obtained from medical records.ResultsAcross ethnic groups, adolescent-reported mother and father acceptance were associated with better diabetes management, whereas mother-reported conflict was associated with poorer diabetes management and more depressive symptoms. Independent of socioeconomic status, Latinos reported lower parental acceptance and higher diabetes conflict with mothers than Caucasians. Ethnicity moderated some associations between relationship quality and outcomes. Specifically, diabetes conflicts with mothers (mother and adolescent report) and fathers (adolescent report) were associated with poorer mother-reported adherence among Caucasians, but not among Latinos.ConclusionsParent-adolescent relationship quality differs and may have different relations with diabetes management across Latinos and Caucasians
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Associations of parent-adolescent relationship quality with type 1 diabetes management and depressive symptoms in Latino and Caucasian youth.
ObjectiveTo examine associations of parent-adolescent relationship quality (parental acceptance and parent-adolescent conflict) with adolescent type 1 diabetes management (adherence and metabolic control) and depressive symptoms in Latinos and Caucasians.MethodsIn all, 118 adolescents and their mothers (56 = Latino, 62 = Caucasian) completed survey measures of parental acceptance, diabetes conflict, adolescent adherence, and adolescent depressive symptoms. Glycemic control was obtained from medical records.ResultsAcross ethnic groups, adolescent-reported mother and father acceptance were associated with better diabetes management, whereas mother-reported conflict was associated with poorer diabetes management and more depressive symptoms. Independent of socioeconomic status, Latinos reported lower parental acceptance and higher diabetes conflict with mothers than Caucasians. Ethnicity moderated some associations between relationship quality and outcomes. Specifically, diabetes conflicts with mothers (mother and adolescent report) and fathers (adolescent report) were associated with poorer mother-reported adherence among Caucasians, but not among Latinos.ConclusionsParent-adolescent relationship quality differs and may have different relations with diabetes management across Latinos and Caucasians