@article{138, abstract = {Autoregulation is the direct modulation of gene expression by the product of the corresponding gene. Autoregulation of bacterial gene expression has been mostly studied at the transcriptional level, when a protein acts as the cognate transcriptional repressor. A recent study investigating dynamics of the bacterial toxin–antitoxin MazEF system has shown how autoregulation at both the transcriptional and post-transcriptional levels affects the heterogeneity of Escherichia coli populations. Toxin–antitoxin systems hold a crucial but still elusive part in bacterial response to stress. This perspective highlights how these modules can also serve as a great model system for investigating basic concepts in gene regulation. However, as the genomic background and environmental conditions substantially influence toxin activation, it is important to study (auto)regulation of toxin–antitoxin systems in well-defined setups as well as in conditions that resemble the environmental niche.}, author = {Nikolic, Nela}, journal = {Current Genetics}, number = {1}, pages = {133--138}, publisher = {Springer}, title = {{Autoregulation of bacterial gene expression: lessons from the MazEF toxin–antitoxin system}}, doi = {10.1007/s00294-018-0879-8}, volume = {65}, year = {2019}, } @article{14001, abstract = {Chiral molecules interact and react differently with other chiral objects, depending on their handedness. Therefore, it is essential to understand and ultimately control the evolution of molecular chirality during chemical reactions. Although highly sophisticated techniques for the controlled synthesis of chiral molecules have been developed, the observation of chirality on the natural femtosecond time scale of a chemical reaction has so far remained out of reach in the gas phase. Here, we demonstrate a general experimental technique, based on high-harmonic generation in tailored laser fields, and apply it to probe the time evolution of molecular chirality during the photodissociation of 2-iodobutane. These measurements show a change in sign and a pronounced increase in the magnitude of the chiral response over the first 100 fs, followed by its decay within less than 500 fs, revealing the photodissociation to achiral products. The observed time evolution is explained in terms of the variation of the electric and magnetic transition-dipole moments between the lowest electronic states of the cation as a function of the reaction coordinate. These results open the path to investigations of the chirality of molecular-reaction pathways, light-induced chirality in chemical processes, and the control of molecular chirality through tailored laser pulses.}, author = {Baykusheva, Denitsa Rangelova and Zindel, Daniel and Svoboda, Vít and Bommeli, Elias and Ochsner, Manuel and Tehlar, Andres and Wörner, Hans Jakob}, issn = {1091-6490}, journal = {Proceedings of the National Academy of Sciences}, keywords = {Multidisciplinary}, number = {48}, pages = {23923--23929}, publisher = {Proceedings of the National Academy of Sciences}, title = {{Real-time probing of chirality during a chemical reaction}}, doi = {10.1073/pnas.1907189116}, volume = {116}, year = {2019}, } @inproceedings{14002, abstract = {The advancement of attosecond chronoscopy has made it possible to reveal ultrashort time dynamics of photoionization [1]. Ionization delay measurements in atomic targets provide a wealth of information about the timing of the photoelectric effect [2], resonances, electron correlations and transport. The extension of this approach to molecules, however, presents great challenges. In addition to the difficulty of identifying correct ionization channels, it is hard to disentangle the role of the anisotropic molecular landscape from the delays inherent to the excitation process itself. Here, we present the measurements of ionization delays from ethyl iodide around the 4d giant dipole resonance of iodine. We employ attosecond streaking spectroscopy, which enables to disentangle the contribution to the delay from the functional ethyl group, being responsible for the characteristic chemical reactivity of the molecule. An attosecond extreme ultraviolet (XUV) pulse ionizes the molecule around the energy of the giant resonance and the released electron is exposed to the ponderomotive force of a synchronized near-infrared (NIR) field, which yields a streaking spectrogram (see figure). Comparative phase analysis of the spectrograms corresponding to iodine 4d and neon 2p emission permits extracting overall photoemission delays for ethyl iodide. The data is recorded for multiple photon energies around the iodine 4d resonance and compared to classical Wigner propagation [3] and quantum scattering [4] calculations. Here the outgoing electron, produced via inner shell ionization of the iodine atom in ethyl iodide, and thereby hardly influenced by the molecular potential during the birth process, acquires the necessary information about the influence of the functional ethyl group during its propagation. We find significant delay contributions that can distinguish between different functional groups, providing a sensitive probe of the local molecular environment [5]. This would stimulate to perform further angle resolved measurements in molecules to probe the potential landscape in three dimension.}, author = {Biswas, Shubhadeep and Liontos, I. and Kamal, A. M. and Kling, N. G. and Alharbi, A. F. and Alharbi, M. and Azzeer, A. M. and Worner, H. J. and Landsman, A. S. and Kling, M. F. and Forg, B. and Schotz, J. and Schweinberger, W. and Ortmann, L. and Zimmermann, T. and Pi, L.-W. and Baykusheva, Denitsa Rangelova and Masood, H. A.}, booktitle = {2019 Conference on Lasers and Electro-Optics Europe & European Quantum Electronics Conference}, isbn = {9781728104706}, location = {Munich, Germany}, publisher = {Institute of Electrical and Electronics Engineers}, title = {{Probing molecular influence on photoemission delays}}, doi = {10.1109/cleoe-eqec.2019.8871819}, year = {2019}, } @inproceedings{14184, abstract = {Learning disentangled representations is considered a cornerstone problem in representation learning. Recently, Locatello et al. (2019) demonstrated that unsupervised disentanglement learning without inductive biases is theoretically impossible and that existing inductive biases and unsupervised methods do not allow to consistently learn disentangled representations. However, in many practical settings, one might have access to a limited amount of supervision, for example through manual labeling of (some) factors of variation in a few training examples. In this paper, we investigate the impact of such supervision on state-of-the-art disentanglement methods and perform a large scale study, training over 52000 models under well-defined and reproducible experimental conditions. We observe that a small number of labeled examples (0.01--0.5\% of the data set), with potentially imprecise and incomplete labels, is sufficient to perform model selection on state-of-the-art unsupervised models. Further, we investigate the benefit of incorporating supervision into the training process. Overall, we empirically validate that with little and imprecise supervision it is possible to reliably learn disentangled representations.}, author = {Locatello, Francesco and Tschannen, Michael and Bauer, Stefan and Rätsch, Gunnar and Schölkopf, Bernhard and Bachem, Olivier}, booktitle = {8th International Conference on Learning Representations}, location = {Virtual}, title = {{Disentangling factors of variation using few labels}}, year = {2019}, } @inproceedings{14189, abstract = {We consider the problem of recovering a common latent source with independent components from multiple views. This applies to settings in which a variable is measured with multiple experimental modalities, and where the goal is to synthesize the disparate measurements into a single unified representation. We consider the case that the observed views are a nonlinear mixing of component-wise corruptions of the sources. When the views are considered separately, this reduces to nonlinear Independent Component Analysis (ICA) for which it is provably impossible to undo the mixing. We present novel identifiability proofs that this is possible when the multiple views are considered jointly, showing that the mixing can theoretically be undone using function approximators such as deep neural networks. In contrast to known identifiability results for nonlinear ICA, we prove that independent latent sources with arbitrary mixing can be recovered as long as multiple, sufficiently different noisy views are available.}, author = {Gresele, Luigi and Rubenstein, Paul K. and Mehrjou, Arash and Locatello, Francesco and Schölkopf, Bernhard}, booktitle = {Proceedings of the 35th Conference on Uncertainty in Artificial Intelligence}, location = {Tel Aviv, Israel}, pages = {217--227}, publisher = {ML Research Press}, title = {{The incomplete Rosetta Stone problem: Identifiability results for multi-view nonlinear ICA}}, volume = {115}, year = {2019}, } @inproceedings{14190, abstract = {Learning meaningful and compact representations with disentangled semantic aspects is considered to be of key importance in representation learning. Since real-world data is notoriously costly to collect, many recent state-of-the-art disentanglement models have heavily relied on synthetic toy data-sets. In this paper, we propose a novel data-set which consists of over one million images of physical 3D objects with seven factors of variation, such as object color, shape, size and position. In order to be able to control all the factors of variation precisely, we built an experimental platform where the objects are being moved by a robotic arm. In addition, we provide two more datasets which consist of simulations of the experimental setup. These datasets provide for the first time the possibility to systematically investigate how well different disentanglement methods perform on real data in comparison to simulation, and how simulated data can be leveraged to build better representations of the real world. We provide a first experimental study of these questions and our results indicate that learned models transfer poorly, but that model and hyperparameter selection is an effective means of transferring information to the real world.}, author = {Gondal, Muhammad Waleed and Wüthrich, Manuel and Miladinović, Đorđe and Locatello, Francesco and Breidt, Martin and Volchkov, Valentin and Akpo, Joel and Bachem, Olivier and Schölkopf, Bernhard and Bauer, Stefan}, booktitle = {Advances in Neural Information Processing Systems}, isbn = {9781713807933}, location = {Vancouver, Canada}, title = {{On the transfer of inductive bias from simulation to the real world: a new disentanglement dataset}}, volume = {32}, year = {2019}, } @inproceedings{14191, abstract = {A broad class of convex optimization problems can be formulated as a semidefinite program (SDP), minimization of a convex function over the positive-semidefinite cone subject to some affine constraints. The majority of classical SDP solvers are designed for the deterministic setting where problem data is readily available. In this setting, generalized conditional gradient methods (aka Frank-Wolfe-type methods) provide scalable solutions by leveraging the so-called linear minimization oracle instead of the projection onto the semidefinite cone. Most problems in machine learning and modern engineering applications, however, contain some degree of stochasticity. In this work, we propose the first conditional-gradient-type method for solving stochastic optimization problems under affine constraints. Our method guarantees O(k−1/3) convergence rate in expectation on the objective residual and O(k−5/12) on the feasibility gap.}, author = {Locatello, Francesco and Yurtsever, Alp and Fercoq, Olivier and Cevher, Volkan}, booktitle = {Advances in Neural Information Processing Systems}, isbn = {9781713807933}, location = {Vancouver, Canada}, pages = {14291–14301}, title = {{Stochastic Frank-Wolfe for composite convex minimization}}, volume = {32}, year = {2019}, } @inproceedings{14193, abstract = {A disentangled representation encodes information about the salient factors of variation in the data independently. Although it is often argued that this representational format is useful in learning to solve many real-world down-stream tasks, there is little empirical evidence that supports this claim. In this paper, we conduct a large-scale study that investigates whether disentangled representations are more suitable for abstract reasoning tasks. Using two new tasks similar to Raven's Progressive Matrices, we evaluate the usefulness of the representations learned by 360 state-of-the-art unsupervised disentanglement models. Based on these representations, we train 3600 abstract reasoning models and observe that disentangled representations do in fact lead to better down-stream performance. In particular, they enable quicker learning using fewer samples.}, author = {Steenkiste, Sjoerd van and Locatello, Francesco and Schmidhuber, Jürgen and Bachem, Olivier}, booktitle = {Advances in Neural Information Processing Systems}, isbn = {9781713807933}, location = {Vancouver, Canada}, title = {{Are disentangled representations helpful for abstract visual reasoning?}}, volume = {32}, year = {2019}, } @inproceedings{14197, abstract = {Recently there has been a significant interest in learning disentangled representations, as they promise increased interpretability, generalization to unseen scenarios and faster learning on downstream tasks. In this paper, we investigate the usefulness of different notions of disentanglement for improving the fairness of downstream prediction tasks based on representations. We consider the setting where the goal is to predict a target variable based on the learned representation of high-dimensional observations (such as images) that depend on both the target variable and an \emph{unobserved} sensitive variable. We show that in this setting both the optimal and empirical predictions can be unfair, even if the target variable and the sensitive variable are independent. Analyzing the representations of more than \num{12600} trained state-of-the-art disentangled models, we observe that several disentanglement scores are consistently correlated with increased fairness, suggesting that disentanglement may be a useful property to encourage fairness when sensitive variables are not observed.}, author = {Locatello, Francesco and Abbati, Gabriele and Rainforth, Tom and Bauer, Stefan and Schölkopf, Bernhard and Bachem, Olivier}, booktitle = {Advances in Neural Information Processing Systems}, isbn = {9781713807933}, location = {Vancouver, Canada}, pages = {14611–14624}, title = {{On the fairness of disentangled representations}}, volume = {32}, year = {2019}, } @inproceedings{14200, abstract = {The key idea behind the unsupervised learning of disentangled representations is that real-world data is generated by a few explanatory factors of variation which can be recovered by unsupervised learning algorithms. In this paper, we provide a sober look at recent progress in the field and challenge some common assumptions. We first theoretically show that the unsupervised learning of disentangled representations is fundamentally impossible without inductive biases on both the models and the data. Then, we train more than 12000 models covering most prominent methods and evaluation metrics in a reproducible large-scale experimental study on seven different data sets. We observe that while the different methods successfully enforce properties ``encouraged'' by the corresponding losses, well-disentangled models seemingly cannot be identified without supervision. Furthermore, increased disentanglement does not seem to lead to a decreased sample complexity of learning for downstream tasks. Our results suggest that future work on disentanglement learning should be explicit about the role of inductive biases and (implicit) supervision, investigate concrete benefits of enforcing disentanglement of the learned representations, and consider a reproducible experimental setup covering several data sets.}, author = {Locatello, Francesco and Bauer, Stefan and Lucic, Mario and Rätsch, Gunnar and Gelly, Sylvain and Schölkopf, Bernhard and Bachem, Olivier}, booktitle = {Proceedings of the 36th International Conference on Machine Learning}, location = {Long Beach, CA, United States}, pages = {4114--4124}, publisher = {ML Research Press}, title = {{Challenging common assumptions in the unsupervised learning of disentangled representations}}, volume = {97}, year = {2019}, } @article{14299, abstract = {DNA origami nano-objects are usually designed around generic single-stranded “scaffolds”. Many properties of the target object are determined by details of those generic scaffold sequences. Here, we enable designers to fully specify the target structure not only in terms of desired 3D shape but also in terms of the sequences used. To this end, we built design tools to construct scaffold sequences de novo based on strand diagrams, and we developed scalable production methods for creating design-specific scaffold strands with fully user-defined sequences. We used 17 custom scaffolds having different lengths and sequence properties to study the influence of sequence redundancy and sequence composition on multilayer DNA origami assembly and to realize efficient one-pot assembly of multiscaffold DNA origami objects. Furthermore, as examples for functionalized scaffolds, we created a scaffold that enables direct, covalent cross-linking of DNA origami via UV irradiation, and we built DNAzyme-containing scaffolds that allow postfolding DNA origami domain separation.}, author = {FAS, Engelhardt and Praetorius, Florian M and Wachauf, CH and Brüggenthies, G and Kohler, F and Kick, B and Kadletz, KL and Pham, PN and Behler, KL and Gerling, T and Dietz, H}, issn = {1936-086x}, journal = {ACS Nano}, number = {5}, pages = {5015--5027}, publisher = {ACS Publications}, title = {{Custom-size, functional, and durable DNA origami with design-specific scaffolds}}, doi = {10.1021/acsnano.9b01025}, volume = {13}, year = {2019}, } @article{5678, abstract = {The order-k Voronoi tessellation of a locally finite set 𝑋⊆ℝ𝑛 decomposes ℝ𝑛 into convex domains whose points have the same k nearest neighbors in X. Assuming X is a stationary Poisson point process, we give explicit formulas for the expected number and total area of faces of a given dimension per unit volume of space. We also develop a relaxed version of discrete Morse theory and generalize by counting only faces, for which the k nearest points in X are within a given distance threshold.}, author = {Edelsbrunner, Herbert and Nikitenko, Anton}, issn = {14320444}, journal = {Discrete and Computational Geometry}, number = {4}, pages = {865–878}, publisher = {Springer}, title = {{Poisson–Delaunay Mosaics of Order k}}, doi = {10.1007/s00454-018-0049-2}, volume = {62}, year = {2019}, } @article{5680, abstract = {Pollinators display a remarkable diversity of foraging strategies with flowering plants, from primarily mutualistic interactions to cheating through nectar robbery. Despite numerous studies on the effect of nectar robbing on components of plant fitness, its contribution to reproductive isolation is unclear. We experimentally tested the impact of different pollinator strategies in a natural hybrid zone between two subspecies of Antirrhinum majus with alternate flower colour guides. On either side of a steep cline in flower colour between Antirrhinum majus pseudomajus (magenta) and A. m. striatum (yellow), we quantified the behaviour of all floral visitors at different time points during the flowering season. Using long-run camera surveys, we quantify the impact of nectar robbing on the number of flowers visited per inflorescence and the flower probing time. We further experimentally tested the effect of nectar robbing on female reproductive success by manipulating the intensity of robbing. While robbing increased over time the number of legitimate visitors tended to decrease concomitantly. We found that the number of flowers pollinated on a focal inflorescence decreased with the number of prior robbing events. However, in the manipulative experiment, fruit set and fruit volume did not vary significantly between low robbing and control treatments. Our findings challenge the idea that robbers have a negative impact on plant fitness through female function. This study also adds to our understanding of the components of pollinator-mediated reproductive isolation and the maintenance of Antirrhinum hybrid zones.}, author = {Andalo, Christophe and Burrus, Monique and Paute, Sandrine and Lauzeral, Christine and Field, David}, issn = {23818115}, journal = {Botany Letters}, number = {1}, pages = {80--92}, publisher = {Taylor and Francis}, title = {{Prevalence of legitimate pollinators and nectar robbers and the consequences for fruit set in an Antirrhinum majus hybrid zone}}, doi = {10.1080/23818107.2018.1545142}, volume = {166}, year = {2019}, } @article{5789, abstract = {Tissue morphogenesis is driven by mechanical forces that elicit changes in cell size, shape and motion. The extent by which forces deform tissues critically depends on the rheological properties of the recipient tissue. Yet, whether and how dynamic changes in tissue rheology affect tissue morphogenesis and how they are regulated within the developing organism remain unclear. Here, we show that blastoderm spreading at the onset of zebrafish morphogenesis relies on a rapid, pronounced and spatially patterned tissue fluidization. Blastoderm fluidization is temporally controlled by mitotic cell rounding-dependent cell–cell contact disassembly during the last rounds of cell cleavages. Moreover, fluidization is spatially restricted to the central blastoderm by local activation of non-canonical Wnt signalling within the blastoderm margin, increasing cell cohesion and thereby counteracting the effect of mitotic rounding on contact disassembly. Overall, our results identify a fluidity transition mediated by loss of cell cohesion as a critical regulator of embryo morphogenesis.}, author = {Petridou, Nicoletta and Grigolon, Silvia and Salbreux, Guillaume and Hannezo, Edouard B and Heisenberg, Carl-Philipp J}, issn = {14657392}, journal = {Nature Cell Biology}, pages = {169–178}, publisher = {Nature Publishing Group}, title = {{Fluidization-mediated tissue spreading by mitotic cell rounding and non-canonical Wnt signalling}}, doi = {10.1038/s41556-018-0247-4}, volume = {21}, year = {2019}, } @article{5790, abstract = {The partial representation extension problem is a recently introduced generalization of the recognition problem. A circle graph is an intersection graph of chords of a circle. We study the partial representation extension problem for circle graphs, where the input consists of a graph G and a partial representation R′ giving some predrawn chords that represent an induced subgraph of G. The question is whether one can extend R′ to a representation R of the entire graph G, that is, whether one can draw the remaining chords into a partially predrawn representation to obtain a representation of G. Our main result is an O(n3) time algorithm for partial representation extension of circle graphs, where n is the number of vertices. To show this, we describe the structure of all representations of a circle graph using split decomposition. This can be of independent interest.}, author = {Chaplick, Steven and Fulek, Radoslav and Klavík, Pavel}, issn = {03649024}, journal = {Journal of Graph Theory}, number = {4}, pages = {365--394}, publisher = {Wiley}, title = {{Extending partial representations of circle graphs}}, doi = {10.1002/jgt.22436}, volume = {91}, year = {2019}, } @inbook{5793, abstract = {The transcription coactivator, Yes-associated protein (YAP), which is a nuclear effector of the Hippo signaling pathway, has been shown to be a mechano-transducer. By using mutant fish and human 3D spheroids, we have recently demonstrated that YAP is also a mechano-effector. YAP functions in three-dimensional (3D) morphogenesis of organ and global body shape by controlling actomyosin-mediated tissue tension. In this chapter, we present a platform that links the findings in fish embryos with human cells. The protocols for analyzing tissue tension-mediated global body shape/organ morphogenesis in vivo and ex vivo using medaka fish embryos and in vitro using human cell spheroids represent useful tools for unraveling the molecular mechanisms by which YAP functions in regulating global body/organ morphogenesis.}, author = {Asaoka, Yoichi and Morita, Hitoshi and Furumoto, Hiroko and Heisenberg, Carl-Philipp J and Furutani-Seiki, Makoto}, booktitle = {The hippo pathway}, editor = {Hergovich, Alexander}, isbn = {978-1-4939-8909-6}, pages = {167--181}, publisher = {Springer}, title = {{Studying YAP-mediated 3D morphogenesis using fish embryos and human spheroids}}, doi = {10.1007/978-1-4939-8910-2_14}, volume = {1893}, year = {2019}, } @article{5817, abstract = {We theoretically study the shapes of lipid vesicles confined to a spherical cavity, elaborating a framework based on the so-called limiting shapes constructed from geometrically simple structural elements such as double-membrane walls and edges. Partly inspired by numerical results, the proposed non-compartmentalized and compartmentalized limiting shapes are arranged in the bilayer-couple phase diagram which is then compared to its free-vesicle counterpart. We also compute the area-difference-elasticity phase diagram of the limiting shapes and we use it to interpret shape transitions experimentally observed in vesicles confined within another vesicle. The limiting-shape framework may be generalized to theoretically investigate the structure of certain cell organelles such as the mitochondrion.}, author = {Kavcic, Bor and Sakashita, A. and Noguchi, H. and Ziherl, P.}, issn = {1744-6848}, journal = {Soft Matter}, number = {4}, pages = {602--614}, publisher = {Royal Society of Chemistry}, title = {{Limiting shapes of confined lipid vesicles}}, doi = {10.1039/c8sm01956h}, volume = {15}, year = {2019}, } @article{5828, abstract = {Hippocampus is needed for both spatial working and reference memories. Here, using a radial eight-arm maze, we examined how the combined demand on these memories influenced CA1 place cell assemblies while reference memories were partially updated. This was contrasted with control tasks requiring only working memory or the update of reference memory. Reference memory update led to the reward-directed place field shifts at newly rewarded arms and to the gradual strengthening of firing in passes between newly rewarded arms but not between those passes that included a familiar-rewarded arm. At the maze center, transient network synchronization periods preferentially replayed trajectories of the next chosen arm in reference memory tasks but the previously visited arm in the working memory task. Hence, reference memory demand was uniquely associated with a gradual, goal novelty-related reorganization of place cell assemblies and with trajectory replay that reflected the animal's decision of which arm to visit next.}, author = {Xu, Haibing and Baracskay, Peter and O'Neill, Joseph and Csicsvari, Jozsef L}, issn = {10974199}, journal = {Neuron}, number = {1}, pages = {119--132.e4}, publisher = {Elsevier}, title = {{Assembly responses of hippocampal CA1 place cells predict learned behavior in goal-directed spatial tasks on the radial eight-arm maze}}, doi = {10.1016/j.neuron.2018.11.015}, volume = {101}, year = {2019}, } @article{5856, abstract = {We give a bound on the ground-state energy of a system of N non-interacting fermions in a three-dimensional cubic box interacting with an impurity particle via point interactions. We show that the change in energy compared to the system in the absence of the impurity is bounded in terms of the gas density and the scattering length of the interaction, independently of N. Our bound holds as long as the ratio of the mass of the impurity to the one of the gas particles is larger than a critical value m∗ ∗≈ 0.36 , which is the same regime for which we recently showed stability of the system.}, author = {Moser, Thomas and Seiringer, Robert}, issn = {14240637}, journal = {Annales Henri Poincare}, number = {4}, pages = {1325–1365}, publisher = {Springer}, title = {{Energy contribution of a point-interacting impurity in a Fermi gas}}, doi = {10.1007/s00023-018-00757-0}, volume = {20}, year = {2019}, } @article{5857, abstract = {A thrackle is a graph drawn in the plane so that every pair of its edges meet exactly once: either at a common end vertex or in a proper crossing. We prove that any thrackle of n vertices has at most 1.3984n edges. Quasi-thrackles are defined similarly, except that every pair of edges that do not share a vertex are allowed to cross an odd number of times. It is also shown that the maximum number of edges of a quasi-thrackle on n vertices is [Formula presented](n−1), and that this bound is best possible for infinitely many values of n.}, author = {Fulek, Radoslav and Pach, János}, issn = {0166218X}, journal = {Discrete Applied Mathematics}, number = {4}, pages = {266--231}, publisher = {Elsevier}, title = {{Thrackles: An improved upper bound}}, doi = {10.1016/j.dam.2018.12.025}, volume = {259}, year = {2019}, }