Highly-parallelized simulation of a pixelated LArTPC on a GPU

The rapid development of general-purpose computing on graphics processing units (GPGPU) is allowing the implementation of highly-parallelized Monte Carlo simulation chains for particle physics experiments. This technique is particularly suitable for the simulation of a pixelated charge readout for time projection chambers, given the large number of channels that this technology employs. Here we present the first implementation of a full microphysical simulator of a liquid argon time projection chamber (LArTPC) equipped with light readout and pixelated charge readout, developed for the DUNE Near Detector. The software is implemented with an end-to-end set of GPU-optimized algorithms. The algorithms have been written in Python and translated into CUDA kernels using Numba, a just-in-time compiler for a subset of Python and NumPy instructions. The GPU implementation achieves a speed up of four orders of magnitude compared with the equivalent CPU version. The simulation of the current induced on 10^3 pixels takes around 1 ms on the GPU, compared with approximately 10 s on the CPU. The results of the simulation are compared against data from a pixel-readout LArTPC prototype

Understanding the foreign policy of autocratic actors: ideology or pragmatism? Russia and the Tymoshenko trial as a case study

While the literature on the autocratic regimes has been rapidly growing in the last years, there still exists a research gap in this field: which impact do autocratic regimes have on the regime transition in the neighbouring countries? The literature on autocracies has demonstrated that autocratic political leaders tend to support each other. This article argues that the external influence of an autocracy may be more complex. The article analyses the case of Russia's international standing in relation to the trial of Yulia Tymoshenko. Using detailed process tracing, it has been shown that in terms of the Russian position, pragmatic goals may undermine ideological goals. Thus, while the main objective of Russia is to ensure the stability of gas contracts, the unintended consequences of its actions undermine the consolidation of autocratic regime in Ukraine. The article builds on the literature on regime transition, autocracy, and international relations