150 research outputs found
On the nature of bright compact radio sources at z>4.5
High-redshift radio-loud quasars are used to, among other things, test the
predictions of cosmological models, set constraints on black hole growth in the
early universe and understand galaxy evolution. Prior to this paper, 20
extragalactic radio sources at redshifts above 4.5 have been imaged with very
long baseline interferometry (VLBI). Here we report on observations of an
additional ten z>4.5 sources at 1.7 and 5 GHz with the European VLBI Network
(EVN), thereby increasing the number of imaged sources by 50%. Combining our
newly observed sources with those from the literature, we create a substantial
sample of 30 z>4.5 VLBI sources, allowing us to study the nature of these
objects. Using spectral indices, variability and brightness temperatures, we
conclude that of the 27 sources with sufficient information to classify, the
radio emission from one source is from star formation, 13 are flat-spectrum
radio quasars and 13 are steep-spectrum sources. We also argue that the
steep-spectrum sources are off-axis (unbeamed) radio sources with rest-frame
self-absorption peaks at or below GHz frequencies and that these sources can be
classified as gigahertz peaked-spectrum (GPS) and megahertz peaked-spectrum
(MPS) sources.Comment: Accepted for publication in Monthly Notices of the Royal Astronomical
Society, 18 pages, 1 figure, 7 table
Expression of a WIN/SHN-type regulator from wheat triggers disorganized proliferation in the Arabidopsis leaf cuticle
Guided Bone Regeneration Using a Novel Magnesium Membrane: A Literature Review and a Report of Two Cases in Humans
Evaluation of a commercial intravaginal thermometer to predict calving in a Hungarian Holstein‐Friesian dairy farm
In this study, the utility of a commercial intravaginal thermometer was evaluated as an automated method for the prediction of calving in a total of 257 healthy pregnant Holstein–Friesian female cattle. The accuracy and the sensitivity of predicting calving within 48 hr before calving were also evaluated. The intravaginal temperature changes from 72 hr before and up to calving were significantly (p ≤ .001) affected by parity, season (summer vs. autumn), the time of day (8 a.m. or 8 p.m.) and the 6-hr time intervals (38.19°C: first interval 0 to 6 hr before calving vs. 38.78°C: twelfth interval 66 to 72 hr before calving), while the gender (p = .943), and the weight of the calf (p = .610), twinning (p = .300), gestation length (p = .186), foetal presentation (p = .123), dystocia (p = .197) and retention of foetal membranes (p = .253) did not affect it significantly. The sensitivity of the SMS of expecting calving within 48 hr and the positive predictive value were 62.4% and 75%, respectively, while the sensitivity and the positive predictive value for the SMS of expulsion reached 100%. It can be concluded that the investigated thermometer is not able to predict calving within 48 hr accurately; however, imminent calving can be accurately alerted
Distinct types of life events interact with 5-HTTLPR in the development of depressive symptoms in an age-dependent manner
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