The flickering radio jet from the quiescent black hole X-ray binary A0620-00

Weakly accreting black hole X-ray binaries launch compact radio jets that persist even in the quiescent spectral state, at X-ray luminosities <1e-5 of the Eddington luminosity. However, radio continuum emission has been detected from only a few of these quiescent systems, and little is known about their radio variability. Jet variability can lead to misclassification of accreting compact objects in quiescence, and affects the detectability of black hole X-ray binaries in next-generation radio surveys. Here we present the results of a radio monitoring campaign of A0620-00, one of the best-studied and least-luminous known quiescent black hole X-ray binaries. We observed A0620-00 at 9.8 GHz using the Karl G. Jansky Very Large Array on 31 epochs from 2017 to 2020, detecting the source ~75% of the time. We see significant variability over all timescales sampled, and the observed flux densities follow a lognormal distribution with a mean of 12.5 uJy and standard deviation of 0.22 dex. In no epoch was A0620-00 as bright as in 2005 (51 +/- 7 uJy), implying either that this original detection was obtained during an unusually bright flare, or that the system is fading in the radio over time. We present tentative evidence that the quiescent radio emission from A0620-00 is less variable than that of V404 Cyg, the only other black hole binary with comparable data. Given that V404 Cyg has a jet radio luminosity ~20 times higher than A0620-00, this comparison could suggest that less luminous jets are less variable in quiescence.Comment: 9 pages, 7 figures, accepted for publication in MNRA

Deterioração de grãos de cultivares de soja, após a maturação das plantas, em Porto Velho-RO.

O objetivo do presente trabalho foi avaliar o efeito do retardamento da colheita sobre deterioração dos grãos de diferentes cultivares de soja

A New Academic Quality at Work Tool (AQ@workT) to Assess the Quality of Life at Work in the Italian Academic Context

The present study provides evidence for a valid and reliable tool, the Academic Quality at Work Tool (AQ@workT), to investigate the quality of life at work in academics within the Italian university sector. The AQ@workT was developed by the QoL@Work research team, namely a group of expert academics in the field of work and organizational psychology affiliated with the Italian Association of Psychologists. The tool is grounded in the job demands-resources model and its psychometric properties were assessed in three studies comprising a wide sample of lecturers, researchers, and professors: a pilot study (N = 120), a calibration study (N = 1084), and a validation study (N = 1481). Reliability and content, construct, and nomological validity were supported, as well as measurement invariance across work role (researchers, associate professors, and full professors) and gender. Evidence from the present study shows that the AQ@workT represents a useful and reliable tool to assist university management to enhance quality of life, to manage work-related stress, and to mitigate the potential for harm to academics, particularly during a pandemic. Future studies, such as longitudinal tests of the AQ@workT, should test predictive validity among the variables in the tool

GPS-determination of along-strike variation in Cascadia margin kinematics: Implications for relative plate motion, Subduction zone coupling, and permanent deformation

High‐precision GPS geodesy in the Pacific Northwest provides the first synoptic view of the along‐strike variation in Cascadia margin kinematics. These results constrain interfering deformation fields in a region where typical earthquake recurrence intervals are one or more orders of magnitude longer than the decades‐long history of seismic monitoring and where geologic studies are sparse. Interseismic strain accumulation contributes greatly to GPS station velocities along the coast. After correction for a simple elastic dislocation model, important residual motions remain, especially south of the international border. The magnitude of northward forearc motion increases southward from western Washington (3–7 mm/yr) to northern and central Oregon (∼9 mm/yr), consistent with oblique convergence and geologic constraints on permanent deformation. The margin‐parallel strain gradient, concentrated in western Washington across the populated Puget Lowlands, compares in magnitude to shortening across the Los Angeles Basin. Thus crustal faulting also contributes to seismic hazard. Farther south in southern Oregon, north‐westward velocities reflect the influence of Pacific‐North America motion and impingement of the Sierra Nevada block on the Pacific Northwest. In contrast to previous notions, some deformation related to the Eastern California shear zone crosses northernmost California in the vicinity of the Klamath Mountains and feeds out to the Gorda plate margin