Search

We present results from the first 22 GHz space very-long-baseline interferometric (VLBI) imaging observations of M87 by RadioAstron. As a part of the Nearby AGN Key Science Program, the source was observed in Feb 2014 at 22 GHz with 21 ground stations, reaching projected $(u,v)$-spacings up to $\sim11\,$G$\lambda$. The imaging experiment was complemented by snapshot RadioAstron data of M87 obtained during 2013--2016 from the AGN Survey Key Science Program. Their longest baselines extend up to $\sim25\,$G$\lambda$. For all these measurements, fringes are detected only up to $\sim$2.8 Earth Diameter or $\sim$3 G$\lambda$ baseline lengths, resulting in a new image with angular resolution of $\sim150\,\mu$as or $\sim20$ Schwarzschild radii spatial resolution. The new image not only shows edge-brightened jet and counterjet structures down to submilliarcsecond scales but also clearly resolves the VLBI core region. While the overall size of the core is comparable to those reported in the literature, the ground-space fringe detection and slightly super-resolved RadioAstron image suggest the presence of substructures in the nucleus, whose minimum brightness temperature exceeds $T_{\rm B, min}\sim10^{12}\,$K. It is challenging to explain the origin of this record-high $T_{\rm B, min}$ value for M87 by pure Doppler boosting effect with a simple conical jet geometry and known jet speed. Therefore, this can be evidence for more extreme Doppler boosting due to a blazar-like small jet viewing angle or highly efficient particle acceleration processes occurring already at the base of the outflow., Comment: 27 pages, 13 figures, accepted for publication in ApJ

Supplemental material, sj-pdf-1-ajs-10.1177_03635465221097939 for Mesenchymal Stem Cell Delivery via Topographically Tenoinductive Collagen Biotextile Enhances Regeneration of Segmental Tendon Defects by Phillip McClellan, Jason G. Ina, Derrick M. Knapik, Ilaha Isali, Greg Learn, Alexis Valente, Yujing Wen, Ruiqi Wen, James M. Anderson, Robert J. Gillespie and Ozan Akkus in The American Journal of Sports Medicine

In theory, forensic science provides objective, dispassionate evidence in criminal justice proceedings often charged with emotion, cognitive biases, and the failings of human recollection. By being theoretically objective and independent from other actors and processes in the criminal justice process, forensic science has the potential to make the criminal process more reliable by reducing both wrongful convictions and unsolved crimes. \ud \ud But how does it work in practice? Its leading role in many wrongful convictions suggests caution. To better understand the actual role of forensic science, we collected data on the prevalence and use of forensic evidence in five jurisdictions in multiple stages of the criminal process. We also analyzed existing data on crime labs and conducted an experimental survey of prosecutors and criminal defense attorneys to measure the effect of forensic evidence on the plea-bargaining process.\ud \ud Our findings are sobering. While forensic evidence is regularly in homicide cases, it is(still) being analyzed in only a small fraction of cases in which it is available. In those few cases, its use is highly limited by resource constraints, resulting in long turnaround times for less serious offenses, which encourage police and prosecutors to rely on other types of evidence. When it is used, it is often tested late in the criminal process, sometimes to meet juror expectations. While an understandable reaction to limited forensic resources, this late timing may lead to both unsolved crimes and pressure to conform to pre existing theories of guilt.\ud \ud Despite the theoretical potential of forensic science to improve the reliability of the criminal process, the way it is actually used squanders many of its advantages. As a result, the potential of forensic evidence to improve the criminal process remains largely unrealized.

'Vraag die prijs die de klant nog net wil betalen' was tot nu toe het meest gebruikte motto in de business-to-business markt. Met andere woorden: maak de prijs bij voorkeur zo hoog mogelijk. Deze strategie blijkt in de praktijk echter lang niet altijd effectief. Hoe moet het dan wél?

Six low-luminosity active galactic nuclei have been imaged at multiple frequencies from 1.7--43 GHz (2.3--15 GHz for three of the galaxies) using the Very Long Baseline Array. In spite of dynamic ranges of about 100 in several frequency bands, all six galaxies remain unresolved, with size limits at 8.4 GHz of 10^3--10^4 times the Schwarzschild radii of the black holes inferred at their galactic centers. The galaxy spectra are roughly flat from 1.7 to 43 GHz, rather than steepening to classical optically thin synchrotron spectra at high frequencies. Although the spectral slopes somewhat resemble predictions for advection-dominated accretion flows, the luminosities are too high for the black hole masses of the galaxies and the slight spectral steepening at high frequencies cannot be explained by standard simple models of such accretion flows. In contrast, compact jets can accommodate the average spectral index, the relatively high radio luminosity, and the unresolved appearance, but only if the jets in all six galaxies are fairly close to our line of sight. This constraint is in agreement with inclination angle predictions for five of the six AGNs based on the dusty torus unification model., Comment: 28 pages, 7 figures, accepted for publication in the Astrophysical Journal