Apercal-The Apertif calibration pipeline

Apertif (APERture Tile In Focus) is one of the Square Kilometre Array (SKA) pathfinder facilities. The Apertif project is an upgrade to the 50-year-old Westerbork Synthesis Radio Telescope (WSRT) using phased-array feed technology. The new receivers create 40 individual beams on the sky, achieving an instantaneous sky coverage of 6.5 square degrees. The primary goal of the Apertif Imaging Survey is to perform a wide survey of 3500 square degrees (AWES) and a medium deep survey of 350 square degrees (AMES) of neutral atomic hydrogen (up to a redshift of 0.26), radio continuum emission and polarisation. Each survey pointing yields 4.6 TB of correlated data. The goal of Apercal is to process this data and fully automatically generate science ready data products for the astronomical community while keeping up with the survey observations. We make use of common astronomical software packages in combination with Python based routines and parallelisation. We use an object oriented module-based approach to ensure easy adaptation of the pipeline. A Jupyter notebook based framework allows user interaction and execution of individual modules as well as a full automatic processing of a complete survey observation. If nothing interrupts processing, we are able to reduce a single pointing survey observation on our five node cluster with 24 physical cores and 256 GB of memory each within 24 h keeping up with the speed of the surveys. The quality of the generated images is sufficient for scientific usage for 44% of the recorded data products with single images reaching dynamic ranges of several thousands. Future improvements will increase this percentage to over 80%. Our design allowed development of the pipeline in parallel to the commissioning of the Apertif system

Incorporation of [³H]uridine into RNA under the influence of dieldrin and polychlorinated biphenyls.

The present study was conducted to determine the influence of two organochlorines, i.e., polychlorinated biphenyl (Aroclor 1242) and dieldrin, or RNA synthesis in elicited peritoneal macrophages. Tritiated uridine ([3H]uridine) incorporation into RNA was used as an index of RNA synthesis. RNA synthesis was depressed in macrophages incubated in the presence of dieldrin in both a time- and dose-related manner. The dieldrin-induced inhibition of RNA synthesis was further exacerbated when the macrophages were actively phagocytosing latex particles. Aroclor 1242 similarly inhibited RNA synthesis in resting macrophages; however, inhibition was not seen until a concentration exceeding 7 ppm of Aroclor 1242 was used in the incubation medium. Dieldrin-induced inhibition of RNA synthesis was observed at levels of 1 ppm. The inhibition of RNA synthesis provides a corroborative index to support the hypothesis previously advanced that the observed in vivo organochlorine-induced immune suppression may be macrophage mediated. Since the observed in vivo immune suppression was manifested in the absence of any morphological changes in the target lymphoid-macrophage tissues, a biochemical lesion, perhaps at the level of RNA synthesis, may be a site for the organochlorine-induced immunosuppression