Classification and Recovery of Radio Signals from Cosmic Ray Induced Air Showers with Deep Learning

Radio emission from air showers enables measurements of cosmic particle kinematics and identity. The radio signals are detected in broadband Megahertz antennas among continuous background noise. We present two deep learning concepts and their performance when applied to simulated data. The first network classifies time traces as signal or background. We achieve a true positive rate of about 90% for signal-to-noise ratios larger than three with a false positive rate below 0.2%. The other network is used to clean the time trace from background and to recover the radio time trace originating from an air shower. Here we achieve a resolution in the energy contained in the trace of about 20% without a bias for $80\%$ of the traces with a signal. The obtained frequency spectrum is cleaned from signals of radio frequency interference and shows the expected shape.Comment: 20 pages, 13 figures, resubmitted to JINS

Study made of corrosion resistance of stainless steel and nickel alloys in nuclear reactor superheaters

Experiments performed under conditions found in nuclear reactor superheaters determine the corrosion rate of stainless steel and nickel alloys used in them. Electropolishing was the primary surface treatment before the corrosion test. Corrosion is determined by weight loss of specimens after defilming

Superconducting undulators with variable polarization and enhanced spectral range

A concept utilizing superconducting magnets for variable polarization insertion devices is presented. The iron-free design enables full variable linear and elliptical polarization over a broad spectral range. With appropriate electrical switching the same device can access higher energies through period-halving, while continuing to provide variable-linear polarization; furthermore, separate switching will allow for period-doubling with full linear and elliptical polarization control. The performance, both in terms of field/spectral performance and in terms of polarization control, is compared to existing permanent magnet EPU devices. Engineering issues associated with the fabrication and implementation of the device are discussed

Localization versus function of Rab3 proteins - Evidence for a common regulatory role in controlling fusion

Rab3A, Rab3B, Rab3C, and Rab3D constitute a family of GTP- binding proteins that are implicated in regulated exocytosis. Various localizations and distinct functions have been proposed for different and occasionally even for the same Rab3 protein. This is exemplified by studies demonstrating that deletion of Rab3A in knock-out mice results in dysregulation of the final stages of exocytosis, whereas overexpression of Rab3A in neuroendocrine cells causes nearly complete inhibition of Ca2+- triggered exocytosis. We have now examined the properties of all Rab3 proteins in the same assays, with the long-term goal of identifying a common conceptual framework for their functions. Using quantitative immunoblotting, we found that all four Rab3 proteins were expressed in brain and endocrine tissues, although at widely different levels. Rab3A, Rab3B, and Rab3C co-localized to synaptic and secretory vesicles consistent with potential redundancy, whereas Rab3D was expressed at high levels only in the endocrine pituitary (where it was more abundant than Rab3A, Rab3B, and Rab3C combined), in exocrine glands, and in adipose tissue. In transfected PC12 cells, all four Rab3 proteins strongly inhibited Ca2+-triggered exocytosis. Except for a mutation that fixes Rab3 into a permanently GDP-bound state, all Rab3 mutations tested had no effect on this inhibition, including a mutation in the calmodulin-binding site that was described as inactivating (Coppola, T., Perret-Menoud, V., Luthi, S., Farnsworth, C. C., Glomset, J. A., and Regazzi, R. (1999) EMBO J. 18, 5885- 5891).:Unexpectedly, overexpression of wild type Rab3A and permanently GTP-bound mutant Rab3A in PC12 cells caused a loss of secretory vesicles and an increase in constitutive, Ca2+- independent exocytosis that correlated with the inhibition of regulated Ca2+-triggered exocytosis. Our data indicate that overexpression of Rab3 in PC12 cells impairs the normal control of the final step in exocytosis, thereby converting the regulated secretory pathway into a constitutive pathway. These results offer an hypothesis that reconciles Rab3 transfection and knockout studies by suggesting that Rab3 functions as a gatekeeper of a late stage in exocytosis