TY - JOUR AB - Abstract RNA editing processes are strikingly different in animals and plants. Up to thousands of specific cytidines are converted into uridines in plant chloroplasts and mitochondria whereas up to millions of adenosines are converted into inosines in animal nucleo-cytosolic RNAs. It is unknown whether these two different RNA editing machineries are mutually incompatible. RNA-binding pentatricopeptide repeat (PPR) proteins are the key factors of plant organelle cytidine-to-uridine RNA editing. The complete absence of PPR mediated editing of cytosolic RNAs might be due to a yet unknown barrier that prevents its activity in the cytosol. Here, we transferred two plant mitochondrial PPR-type editing factors into human cell lines to explore whether they could operate in the nucleo-cytosolic environment. PPR56 and PPR65 not only faithfully edited their native, co-transcribed targets but also different sets of off-targets in the human background transcriptome. More than 900 of such off-targets with editing efficiencies up to 91%, largely explained by known PPR-RNA binding properties, were identified for PPR56. Engineering two crucial amino acid positions in its PPR array led to predictable shifts in target recognition. We conclude that plant PPR editing factors can operate in the entirely different genetic environment of the human nucleo-cytosol and can be intentionally re-engineered towards new targets. AU - Lesch, Elena AU - Schilling, Maximilian T AU - Brenner, Sarah AU - Yang, Yingying AU - Gruss, Oliver J AU - Knoop, Volker AU - Schallenberg-Rüdinger, Mareike ID - 50149 IS - 17 JF - Nucleic Acids Research KW - Genetics SN - 0305-1048 TI - Plant mitochondrial RNA editing factors can perform targeted C-to-U editing of nuclear transcripts in human cells VL - 50 ER - TY - JOUR AB - N-body methods are one of the essential algorithmic building blocks of high-performance and parallel computing. Previous research has shown promising performance for implementing n-body simulations with pairwise force calculations on FPGAs. However, to avoid challenges with accumulation and memory access patterns, the presented designs calculate each pair of forces twice, along with both force sums of the involved particles. Also, they require large problem instances with hundreds of thousands of particles to reach their respective peak performance, limiting the applicability for strong scaling scenarios. This work addresses both issues by presenting a novel FPGA design that uses each calculated force twice and overlaps data transfers and computations in a way that allows to reach peak performance even for small problem instances, outperforming previous single precision results even in double precision, and scaling linearly over multiple interconnected FPGAs. For a comparison across architectures, we provide an equally optimized CPU reference, which for large problems actually achieves higher peak performance per device, however, given the strong scaling advantages of the FPGA design, in parallel setups with few thousand particles per device, the FPGA platform achieves highest performance and power efficiency. AU - Menzel, Johannes AU - Plessl, Christian AU - Kenter, Tobias ID - 28099 IS - 1 JF - ACM Transactions on Reconfigurable Technology and Systems SN - 1936-7406 TI - The Strong Scaling Advantage of FPGAs in HPC for N-body Simulations VL - 15 ER - TY - CONF AU - Meyer, Marius ID - 27365 T2 - Proceedings of the 11th International Symposium on Highly Efficient Accelerators and Reconfigurable Technologies TI - Towards Performance Characterization of FPGAs in Context of HPC using OpenCL Benchmarks ER - TY - CONF AU - Nickchen, Tobias AU - Heindorf, Stefan AU - Engels, Gregor ID - 20886 T2 - Proceedings of the IEEE/CVF Winter Conference on Applications of Computer Vision TI - Generating Physically Sound Training Data for Image Recognition of Additively Manufactured Parts ER - TY - JOUR AB - Abstract The defining feature of active particles is that they constantly propel themselves by locally converting chemical energy into directed motion. This active self-propulsion prevents them from equilibrating with their thermal environment (e.g. an aqueous solution), thus keeping them permanently out of equilibrium. Nevertheless, the spatial dynamics of active particles might share certain equilibrium features, in particular in the steady state. We here focus on the time-reversal symmetry of individual spatial trajectories as a distinct equilibrium characteristic. We investigate to what extent the steady-state trajectories of a trapped active particle obey or break this time-reversal symmetry. Within the framework of active Ornstein–Uhlenbeck particles we find that the steady-state trajectories in a harmonic potential fulfill path-wise time-reversal symmetry exactly, while this symmetry is typically broken in anharmonic potentials. AU - Dabelow, Lennart AU - Bo, Stefano AU - Eichhorn, Ralf ID - 32243 IS - 3 JF - Journal of Statistical Mechanics: Theory and Experiment KW - Statistics KW - Probability and Uncertainty KW - Statistics and Probability KW - Statistical and Nonlinear Physics SN - 1742-5468 TI - How irreversible are steady-state trajectories of a trapped active particle? VL - 2021 ER - TY - GEN AB - We push the boundaries of electronic structure-based \textit{ab-initio} molecular dynamics (AIMD) beyond 100 million atoms. This scale is otherwise barely reachable with classical force-field methods or novel neural network and machine learning potentials. We achieve this breakthrough by combining innovations in linear-scaling AIMD, efficient and approximate sparse linear algebra, low and mixed-precision floating-point computation on GPUs, and a compensation scheme for the errors introduced by numerical approximations. The core of our work is the non-orthogonalized local submatrix method (NOLSM), which scales very favorably to massively parallel computing systems and translates large sparse matrix operations into highly parallel, dense matrix operations that are ideally suited to hardware accelerators. We demonstrate that the NOLSM method, which is at the center point of each AIMD step, is able to achieve a sustained performance of 324 PFLOP/s in mixed FP16/FP32 precision corresponding to an efficiency of 67.7% when running on 1536 NVIDIA A100 GPUs. AU - Schade, Robert AU - Kenter, Tobias AU - Elgabarty, Hossam AU - Lass, Michael AU - Schütt, Ole AU - Lazzaro, Alfio AU - Pabst, Hans AU - Mohr, Stephan AU - Hutter, Jürg AU - Kühne, Thomas D. AU - Plessl, Christian ID - 32244 T2 - arXiv:2104.08245 TI - Towards Electronic Structure-Based Ab-Initio Molecular Dynamics Simulations with Hundreds of Millions of Atoms ER - TY - GEN AB - Optical travelling wave antennas offer unique opportunities to control and selectively guide light into a specific direction which renders them as excellent candidates for optical communication and sensing. These applications require state of the art engineering to reach optimized functionalities such as high directivity and radiation efficiency, low side lobe level, broadband and tunable capabilities, and compact design. In this work we report on the numerical optimization of the directivity of optical travelling wave antennas made from low-loss dielectric materials using full-wave numerical simulations in conjunction with a particle swarm optimization algorithm. The antennas are composed of a reflector and a director deposited on a glass substrate and an emitter placed in the feed gap between them serves as an internal source of excitation. In particular, we analysed antennas with rectangular- and horn-shaped directors made of either Hafnium dioxide or Silicon. The optimized antennas produce highly directional emission due to the presence of two dominant guided TE modes in the director in addition to leaky modes. These guided modes dominate the far-field emission pattern and govern the direction of the main lobe emission which predominately originates from the end facet of the director. Our work also provides a comprehensive analysis of the modes, radiation patterns, parametric influences, and bandwidths of the antennas that highlights their robust nature. AU - Farheen, Henna AU - Leuteritz, Till AU - Linden, Stefan AU - Myroshnychenko, Viktor AU - Förstner, Jens ID - 32245 T2 - arXiv:2106.02468 TI - Optimization of optical waveguide antennas for directive emission of light ER - TY - GEN AB - The interaction between quantum light and matter is being intensively studied for systems that are enclosed in high-$Q$ cavities which strongly enhance the light-matter coupling. However, for many applications, cavities with lower $Q$-factors are preferred due to the increased spectral width of the cavity mode. Here, we investigate the interaction between quantum light and matter represented by a $\Lambda$-type three-level system in lossy cavities, assuming that cavity losses are the dominant loss mechanism. We demonstrate that cavity losses lead to non-trivial steady states of the electronic occupations that can be controlled by the loss rate and the initial statistics of the quantum fields. The mechanism of formation of such steady states can be understood on the basis of the equations of motion. Analytical expressions for steady states and their numerical simulations are presented and discussed. AU - Rose, H. AU - Tikhonova, O. V. AU - Meier, T. AU - Sharapova, P. ID - 32236 T2 - arXiv:2109.00842 TI - Steady states of $Λ$-type three-level systems excited by quantum light in lossy cavities ER - TY - JOUR AU - Kaczmarek, Olaf AU - Mazur, Lukas AU - Sharma, Sayantan ID - 46122 IS - 9 JF - Physical Review D SN - 2470-0010 TI - Eigenvalue spectra of QCD and the fate of UA(1) breaking towards the chiral limit VL - 104 ER - TY - JOUR AU - Altenkort, Luis AU - Eller, Alexander M. AU - Kaczmarek, O. AU - Mazur, Lukas AU - Moore, Guy D. AU - Shu, H.-T. ID - 46124 IS - 1 JF - Physical Review D SN - 2470-0010 TI - Heavy quark momentum diffusion from the lattice using gradient flow VL - 103 ER -