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- Ackermann, M., et al.
(författare)
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Gamma-Ray Blazars within the First 2 Billion Years
- 2017
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Ingår i: Astrophysical Journal Letters. - : Institute of Physics Publishing (IOPP). - 2041-8205 .- 2041-8213. ; 837:1
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Tidskriftsartikel (refereegranskat)abstract
- The detection of high-redshift (z > 3) blazars enables the study of the evolution of the most luminous relativistic jets over cosmic time. More importantly, high-redshift blazars tend to host massive black holes and can be used to constrain the space density of heavy black holes in the early universe. Here, we report the first detection with the Fermi-Large Area Telescope of five γ-ray-emitting blazars beyond z = 3.1, more distant than any blazars previously detected in γ-rays. Among these five objects, NVSS J151002+570243 is now the most distant known γ-ray-emitting blazar at z = 4.31. These objects have steeply falling γ-ray spectral energy distributions (SEDs), and those that have been observed in X-rays have a very hard X-ray spectrum, both typical of powerful blazars. Their Compton dominance (ratio of the inverse Compton to synchrotron peak luminosities) is also very large (>20). All of these properties place these objects among the most extreme members of the blazar population. Their optical spectra and the modeling of their optical-UV SEDs confirm that these objects harbor massive black holes (MBH ∼ 10 8-10 Mo ). We find that, at z ≈ 4, the space density of >109 Mo black holes hosted in radio-loud and radio-quiet active galactic nuclei are similar, implying that radio-loudness may play a key role in rapid black hole growth in the early universe.
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| 2. |
- Nowak-Sliwinska, Patrycja, et al.
(författare)
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Consensus guidelines for the use and interpretation of angiogenesis assays
- 2018
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Ingår i: Angiogenesis. - : Springer. - 0969-6970 .- 1573-7209. ; 21:3, s. 425-532
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Forskningsöversikt (refereegranskat)abstract
- The formation of new blood vessels, or angiogenesis, is a complex process that plays important roles in growth and development, tissue and organ regeneration, as well as numerous pathological conditions. Angiogenesis undergoes multiple discrete steps that can be individually evaluated and quantified by a large number of bioassays. These independent assessments hold advantages but also have limitations. This article describes in vivo, ex vivo, and in vitro bioassays that are available for the evaluation of angiogenesis and highlights critical aspects that are relevant for their execution and proper interpretation. As such, this collaborative work is the first edition of consensus guidelines on angiogenesis bioassays to serve for current and future reference.
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| 3. |
- Chu, S. N., et al.
(författare)
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Field evaluation of a low-powered, profiling pCO2 system in coastal Washington
- 2020
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Ingår i: Limnology and Oceanography: Methods. - : Wiley. - 1541-5856. ; 18:6, s. 280-296
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Tidskriftsartikel (refereegranskat)abstract
- Summertime upwelling of deep, corrosive waters on the continental shelf of the northern California Current System can exacerbate ocean acidification conditions, providing unsuitable environments for development of calcifying organisms and finfish that are important to the local economy. To better understand the carbonate system in this dynamic region, two recently developed technologies were combined with other sensors to obtain high-frequency carbon profile data from July 2017 to September 2017. The compact, low-power sensor package was composed of an optical sensor for partial pressure of carbon dioxide (pCO2 optode, Aanderaa model #4797) integrated onto a wave-powered PRofiling crAWLER (PRAWLER). The PRAWLER profiled from 3 to 80 m, stopping at fixed depths for varying lengths of time to allow for pCO2 equilibration. pCO2 derived from a regional empirical algorithm was used to correct optode drift using data at 80 m. Near-surface adjusted optode pCO2 agreed within 6 ± 42 μatm to surface pCO2 from a nearby Moored Autonomous pCO2 instrument. Throughout the water column, optode pCO2 compared to algorithm pCO2 within −28 ± 66 μatm. Overall, optode uncertainty was 35–72 μatm based on root-mean-square errors from all comparison data sets. Errors are attributed to optode calibration, adjustment, algorithm uncertainty, and environmental variability between optode and reference data. Improvements for optode performance within this profiling application include using more stable sensing foils, in situ calibration, and pumped flow over the sensing foil. Additionally, the study revealed undersaturated (corrosive) waters with respect to aragonite below 60 m throughout the deployment that reached up to 40 m by mid-September. © 2020 The Authors. Limnology and Oceanography: Methods published by Wiley Periodicals, Inc. on behalf of Association for the Sciences of Limnology and Oceanography.
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