TY - JOUR AB - We consider the motion of a droplet bouncing on a vibrating bath of the same fluid in the presence of a central potential. We formulate a rotation symmetry-reduced description of this system, which allows for the straightforward application of dynamical systems theory tools. As an illustration of the utility of the symmetry reduction, we apply it to a model of the pilot-wave system with a central harmonic force. We begin our analysis by identifying local bifurcations and the onset of chaos. We then describe the emergence of chaotic regions and their merging bifurcations, which lead to the formation of a global attractor. In this final regime, the droplet’s angular momentum spontaneously changes its sign as observed in the experiments of Perrard et al. AU - Budanur, Nazmi B AU - Fleury, Marc ID - 5878 IS - 1 JF - Chaos: An Interdisciplinary Journal of Nonlinear Science SN - 1054-1500 TI - State space geometry of the chaotic pilot-wave hydrodynamics VL - 29 ER - TY - JOUR AB - Cryo-electron tomography (cryo-ET) provides unprecedented insights into the molecular constituents of biological environments. In combination with an image processing method called subtomogram averaging (STA), detailed 3D structures of biological molecules can be obtained in large, irregular macromolecular assemblies or in situ, without the need for purification. The contextual meta-information these methods also provide, such as a protein’s location within its native environment, can then be combined with functional data. This allows the derivation of a detailed view on the physiological or pathological roles of proteins from the molecular to cellular level. Despite their tremendous potential in in situ structural biology, cryo-ET and STA have been restricted by methodological limitations, such as the low obtainable resolution. Exciting progress now allows one to reach unprecedented resolutions in situ, ranging in optimal cases beyond the nanometer barrier. Here, I review current frontiers and future challenges in routinely determining high-resolution structures in in situ environments using cryo-ET and STA. AU - Schur, Florian KM ID - 6343 IS - 10 JF - Current Opinion in Structural Biology SN - 0959-440X TI - Toward high-resolution in situ structural biology with cryo-electron tomography and subtomogram averaging VL - 58 ER - TY - CONF AB - Safety and security are major concerns in the development of Cyber-Physical Systems (CPS). Signal temporal logic (STL) was proposedas a language to specify and monitor the correctness of CPS relativeto formalized requirements. Incorporating STL into a developmentprocess enables designers to automatically monitor and diagnosetraces, compute robustness estimates based on requirements, andperform requirement falsification, leading to productivity gains inverification and validation activities; however, in its current formSTL is agnostic to the input/output classification of signals, andthis negatively impacts the relevance of the analysis results.In this paper we propose to make the interface explicit in theSTL language by introducing input/output signal declarations. Wethen define new measures of input vacuity and output robustnessthat better reflect the nature of the system and the specification in-tent. The resulting framework, which we call interface-aware signaltemporal logic (IA-STL), aids verification and validation activities.We demonstrate the benefits of IA-STL on several CPS analysisactivities: (1) robustness-driven sensitivity analysis, (2) falsificationand (3) fault localization. We describe an implementation of our en-hancement to STL and associated notions of robustness and vacuityin a prototype extension of Breach, a MATLAB®/Simulink®toolboxfor CPS verification and validation. We explore these methodologi-cal improvements and evaluate our results on two examples fromthe automotive domain: a benchmark powertrain control systemand a hydrogen fuel cell system. AU - Ferrere, Thomas AU - Nickovic, Dejan AU - Donzé, Alexandre AU - Ito, Hisahiro AU - Kapinski, James ID - 6428 SN - 9781450362825 T2 - Proceedings of the 2019 22nd ACM International Conference on Hybrid Systems: Computation and Control TI - Interface-aware signal temporal logic ER - TY - JOUR AB - This paper investigates the use of fundamental solutions for animating detailed linear water surface waves. We first propose an analytical solution for efficiently animating circular ripples in closed form. We then show how to adapt the method of fundamental solutions (MFS) to create ambient waves interacting with complex obstacles. Subsequently, we present a novel wavelet-based discretization which outperforms the state of the art MFS approach for simulating time-varying water surface waves with moving obstacles. Our results feature high-resolution spatial details, interactions with complex boundaries, and large open ocean domains. Our method compares favorably with previous work as well as known analytical solutions. We also present comparisons between our method and real world examples. AU - Schreck, Camille AU - Hafner, Christian AU - Wojtan, Christopher J ID - 6442 IS - 4 JF - ACM Transactions on Graphics TI - Fundamental solutions for water wave animation VL - 38 ER - TY - JOUR AB - Phase-field methods have long been used to model the flow of immiscible fluids. Their ability to naturally capture interface topological changes is widely recognized, but their accuracy in simulating flows of real fluids in practical geometries is not established. We here quantitatively investigate the convergence of the phase-field method to the sharp-interface limit with simulations of two-phase pipe flow. We focus on core-annular flows, in which a highly viscous fluid is lubricated by a less viscous fluid, and validate our simulations with an analytic laminar solution, a formal linear stability analysis and also in the fully nonlinear regime. We demonstrate the ability of the phase-field method to accurately deal with non-rectangular geometry, strong advection, unsteady fluctuations and large viscosity contrast. We argue that phase-field methods are very promising for quantitatively studying moderately turbulent flows, especially at high concentrations of the disperse phase. AU - Song, Baofang AU - Plana, Carlos AU - Lopez Alonso, Jose M AU - Avila, Marc ID - 6413 JF - International Journal of Multiphase Flow SN - 03019322 TI - Phase-field simulation of core-annular pipe flow VL - 117 ER - TY - JOUR AB - Characterizing the fitness landscape, a representation of fitness for a large set of genotypes, is key to understanding how genetic information is interpreted to create functional organisms. Here we determined the evolutionarily-relevant segment of the fitness landscape of His3, a gene coding for an enzyme in the histidine synthesis pathway, focusing on combinations of amino acid states found at orthologous sites of extant species. Just 15% of amino acids found in yeast His3 orthologues were always neutral while the impact on fitness of the remaining 85% depended on the genetic background. Furthermore, at 67% of sites, amino acid replacements were under sign epistasis, having both strongly positive and negative effect in different genetic backgrounds. 46% of sites were under reciprocal sign epistasis. The fitness impact of amino acid replacements was influenced by only a few genetic backgrounds but involved interaction of multiple sites, shaping a rugged fitness landscape in which many of the shortest paths between highly fit genotypes are inaccessible. AU - Pokusaeva, Victoria AU - Usmanova, Dinara R. AU - Putintseva, Ekaterina V. AU - Espinar, Lorena AU - Sarkisyan, Karen AU - Mishin, Alexander S. AU - Bogatyreva, Natalya S. AU - Ivankov, Dmitry AU - Akopyan, Arseniy AU - Avvakumov, Sergey AU - Povolotskaya, Inna S. AU - Filion, Guillaume J. AU - Carey, Lucas B. AU - Kondrashov, Fyodor ID - 6419 IS - 4 JF - PLoS Genetics TI - An experimental assay of the interactions of amino acids from orthologous sequences shaping a complex fitness landscape VL - 15 ER - TY - JOUR AB - Polycomb group (PcG) proteins play critical roles in the epigenetic inheritance of cell fate. The Polycomb Repressive Complexes PRC1 and PRC2 catalyse distinct chromatin modifications to enforce gene silencing, but how transcriptional repression is propagated through mitotic cell divisions remains a key unresolved question. Using reversible tethering of PcG proteins to ectopic sites in mouse embryonic stem cells, here we show that PRC1 can trigger transcriptional repression and Polycomb-dependent chromatin modifications. We find that canonical PRC1 (cPRC1), but not variant PRC1, maintains gene silencing through cell division upon reversal of tethering. Propagation of gene repression is sustained by cis-acting histone modifications, PRC2-mediated H3K27me3 and cPRC1-mediated H2AK119ub1, promoting a sequence-independent feedback mechanism for PcG protein recruitment. Thus, the distinct PRC1 complexes present in vertebrates can differentially regulate epigenetic maintenance of gene silencing, potentially enabling dynamic heritable responses to complex stimuli. Our findings reveal how PcG repression is potentially inherited in vertebrates. AU - Moussa, Hagar F. AU - Bsteh, Daniel AU - Yelagandula, Ramesh AU - Pribitzer, Carina AU - Stecher, Karin AU - Bartalska, Katarina AU - Michetti, Luca AU - Wang, Jingkui AU - Zepeda-Martinez, Jorge A. AU - Elling, Ulrich AU - Stuckey, Jacob I. AU - James, Lindsey I. AU - Frye, Stephen V. AU - Bell, Oliver ID - 6412 IS - 1 JF - Nature Communications TI - Canonical PRC1 controls sequence-independent propagation of Polycomb-mediated gene silencing VL - 10 ER - TY - JOUR AB - Ant invasions are often harmful to native species communities. Their pathogens and host disease defense mechanisms may be one component of their devastating success. First, they can introduce harmful diseases to their competitors in the introduced range, to which they themselves are tolerant. Second, their supercolonial social structure of huge multi-queen nest networks means that they will harbor a broad pathogen spectrum and high pathogen load while remaining resilient, unlike the smaller, territorial colonies of the native species. Thus, it is likely that invasive ants act as a disease reservoir, promoting their competitive advantage and invasive success. AU - Cremer, Sylvia ID - 6415 JF - Current Opinion in Insect Science SN - 22145745 TI - Pathogens and disease defense of invasive ants VL - 33 ER - TY - GEN AU - Pokusaeva, Victoria AU - Usmanova, Dinara R. AU - Putintseva, Ekaterina V. AU - Espinar, Lorena AU - Sarkisyan, Karen AU - Mishin, Alexander S. AU - Bogatyreva, Natalya S. AU - Ivankov, Dmitry AU - Akopyan, Arseniy AU - Avvakumov, Sergey AU - Povolotskaya, Inna S. AU - Filion, Guillaume J. AU - Carey, Lucas B. AU - Kondrashov, Fyodor ID - 9790 TI - A statistical summary of segment libraries and sequencing results ER - TY - GEN AU - Pokusaeva, Victoria AU - Usmanova, Dinara R. AU - Putintseva, Ekaterina V. AU - Espinar, Lorena AU - Sarkisyan, Karen AU - Mishin, Alexander S. AU - Bogatyreva, Natalya S. AU - Ivankov, Dmitry AU - Akopyan, Arseniy AU - Povolotskaya, Inna S. AU - Filion, Guillaume J. AU - Carey, Lucas B. AU - Kondrashov, Fyodor ID - 9797 TI - A statistical summary of segment libraries and sequencing results ER -