@article{12681, abstract = {The dissolution of minute concentration of polymers in wall-bounded flows is well-known for its unparalleled ability to reduce turbulent friction drag. Another phenomenon, elasto-inertial turbulence (EIT), has been far less studied even though elastic instabilities have already been observed in dilute polymer solutions before the discovery of polymer drag reduction. EIT is a chaotic state driven by polymer dynamics that is observed across many orders of magnitude in Reynolds number. It involves energy transfer from small elastic scales to large flow scales. The investigation of the mechanisms of EIT offers the possibility to better understand other complex phenomena such as elastic turbulence and maximum drag reduction. In this review, we survey recent research efforts that are advancing the understanding of the dynamics of EIT. We highlight the fundamental differences between EIT and Newtonian/inertial turbulence from the perspective of experiments, numerical simulations, instabilities, and coherent structures. Finally, we discuss the possible links between EIT and elastic turbulence and polymer drag reduction, as well as the remaining challenges in unraveling the self-sustaining mechanism of EIT.}, author = {Dubief, Yves and Terrapon, Vincent E. and Hof, Björn}, issn = {1545-4479}, journal = {Annual Review of Fluid Mechanics}, number = {1}, pages = {675--705}, publisher = {Annual Reviews}, title = {{Elasto-inertial turbulence}}, doi = {10.1146/annurev-fluid-032822-025933}, volume = {55}, year = {2023}, } @article{12682, abstract = {Since the seminal studies by Osborne Reynolds in the nineteenth century, pipe flow has served as a primary prototype for investigating the transition to turbulence in wall-bounded flows. Despite the apparent simplicity of this flow, various facets of this problem have occupied researchers for more than a century. Here we review insights from three distinct perspectives: (a) stability and susceptibility of laminar flow, (b) phase transition and spatiotemporal dynamics, and (c) dynamical systems analysis of the Navier—Stokes equations. We show how these perspectives have led to a profound understanding of the onset of turbulence in pipe flow. Outstanding open points, applications to flows of complex fluids, and similarities with other wall-bounded flows are discussed.}, author = {Avila, Marc and Barkley, Dwight and Hof, Björn}, issn = {0066-4189}, journal = {Annual Review of Fluid Mechanics}, pages = {575--602}, publisher = {Annual Reviews}, title = {{Transition to turbulence in pipe flow}}, doi = {10.1146/annurev-fluid-120720-025957}, volume = {55}, year = {2023}, } @article{12683, abstract = {We study the eigenvalue trajectories of a time dependent matrix Gt=H+itvv∗ for t≥0, where H is an N×N Hermitian random matrix and v is a unit vector. In particular, we establish that with high probability, an outlier can be distinguished at all times t>1+N−1/3+ϵ, for any ϵ>0. The study of this natural process combines elements of Hermitian and non-Hermitian analysis, and illustrates some aspects of the intrinsic instability of (even weakly) non-Hermitian matrices.}, author = {Dubach, Guillaume and Erdös, László}, issn = {1083-589X}, journal = {Electronic Communications in Probability}, pages = {1--13}, publisher = {Institute of Mathematical Statistics}, title = {{Dynamics of a rank-one perturbation of a Hermitian matrix}}, doi = {10.1214/23-ECP516}, volume = {28}, year = {2023}, } @misc{12693, abstract = {See Readme File for further information.}, author = {Cremer, Sylvia}, publisher = {Institute of Science and Technology Austria}, title = {{Source data for Metzler et al, 2023: Trade-offs between immunity and competitive ability in fighting ant males }}, doi = {10.15479/AT:ISTA:12693}, year = {2023}, } @article{12696, abstract = {Background: Fighting disease while fighting rivals exposes males to constraints and tradeoffs during male-male competition. We here tested how both the stage and intensity of infection with the fungal pathogen Metarhizium robertsii interfered with fighting success in Cardiocondyla obscurior ant males. Males of this species have evolved long lifespans during which they can gain many matings with the young queens of the colony, if successful in male-male competition. Since male fights occur inside the colony, the outcome of male-male competition can further be biased by interference of the colony’s worker force. Results: We found that severe, but not yet mild, infection strongly impaired male fighting success. In late-stage infection, this could be attributed to worker aggression directed towards the infected rather than the healthy male and an already very high male morbidity even in the absence of fighting. Shortly after pathogen exposure, however, male mortality was particularly increased during combat. Since these males mounted a strong immune response, their reduced fighting success suggests a trade-off between immune investment and competitive ability already early in the infection. Even if the males themselves showed no difference in the number of attacks they raised against their healthy rivals across infection stages and levels, severely infected males were thus losing in male-male competition from an early stage of infection on. Conclusions: Males of the ant C. obscurior have evolved high immune investment, triggering an effective immune response very fast after fungal exposure. This allows them to cope with mild pathogen exposures without cost to their success in male-male competition, and hence to gain multiple mating opportunities with the emerging virgin queens of the colony. Under severe infection, however, they are weak fighters and rarely survive a combat already at early infection when raising an immune response, as well as at progressed infection, when they are morbid and preferentially targeted by worker aggression. Workers thereby remove males that pose a future disease threat by biasing male-male competition. Our study thus revealed a novel social immunity mechanism how social insect workers protect the colony against disease risk.}, author = {Metzler, Sina and Kirchner, Jessica and Grasse, Anna V and Cremer, Sylvia}, issn = {2730-7182}, journal = {BMC Ecology and Evolution}, publisher = {Springer Nature}, title = {{Trade-offs between immunity and competitive ability in fighting ant males}}, doi = {10.1186/s12862-023-02137-7}, volume = {23}, year = {2023}, } @article{12697, abstract = {Models for same-material contact electrification in granular media often rely on a local charge-driving parameter whose spatial variations lead to a stochastic origin for charge exchange. Measuring the charge transfer from individual granular spheres after contacts with substrates of the same material, we find instead a “global” charging behavior, coherent over the sample’s whole surface. Cleaning and baking samples fully resets charging magnitude and direction, which indicates the underlying global parameter is not intrinsic to the material, but acquired from its history. Charging behavior is randomly and irreversibly affected by changes in relative humidity, hinting at a mechanism where adsorbates, in particular, water, are fundamental to the charge-transfer process.}, author = {Grosjean, Galien M and Waitukaitis, Scott R}, issn = {1079-7114}, journal = {Physical Review Letters}, keywords = {General Physics, Electrostatics, Triboelectricity, Soft Matter, Acoustic Levitation, Granular Materials}, number = {9}, publisher = {American Physical Society}, title = {{Single-collision statistics reveal a global mechanism driven by sample history for contact electrification in granular media}}, doi = {10.1103/physrevlett.130.098202}, volume = {130}, year = {2023}, } @article{12702, abstract = {Hydrocarbon mixtures are extremely abundant in the Universe, and diamond formation from them can play a crucial role in shaping the interior structure and evolution of planets. With first-principles accuracy, we first estimate the melting line of diamond, and then reveal the nature of chemical bonding in hydrocarbons at extreme conditions. We finally establish the pressure-temperature phase boundary where it is thermodynamically possible for diamond to form from hydrocarbon mixtures with different atomic fractions of carbon. Notably, here we show a depletion zone at pressures above 200 GPa and temperatures below 3000 K-3500 K where diamond formation is thermodynamically favorable regardless of the carbon atomic fraction, due to a phase separation mechanism. The cooler condition of the interior of Neptune compared to Uranus means that the former is much more likely to contain the depletion zone. Our findings can help explain the dichotomy of the two ice giants manifested by the low luminosity of Uranus, and lead to a better understanding of (exo-)planetary formation and evolution.}, author = {Cheng, Bingqing and Hamel, Sebastien and Bethkenhagen, Mandy}, issn = {2041-1723}, journal = {Nature Communications}, publisher = {Springer Nature}, title = {{Thermodynamics of diamond formation from hydrocarbon mixtures in planets}}, doi = {10.1038/s41467-023-36841-1}, volume = {14}, year = {2023}, } @article{12704, abstract = {Adversarial training (i.e., training on adversarially perturbed input data) is a well-studied method for making neural networks robust to potential adversarial attacks during inference. However, the improved robustness does not come for free but rather is accompanied by a decrease in overall model accuracy and performance. Recent work has shown that, in practical robot learning applications, the effects of adversarial training do not pose a fair trade-off but inflict a net loss when measured in holistic robot performance. This work revisits the robustness-accuracy trade-off in robot learning by systematically analyzing if recent advances in robust training methods and theory in conjunction with adversarial robot learning, are capable of making adversarial training suitable for real-world robot applications. We evaluate three different robot learning tasks ranging from autonomous driving in a high-fidelity environment amenable to sim-to-real deployment to mobile robot navigation and gesture recognition. Our results demonstrate that, while these techniques make incremental improvements on the trade-off on a relative scale, the negative impact on the nominal accuracy caused by adversarial training still outweighs the improved robustness by an order of magnitude. We conclude that although progress is happening, further advances in robust learning methods are necessary before they can benefit robot learning tasks in practice.}, author = {Lechner, Mathias and Amini, Alexander and Rus, Daniela and Henzinger, Thomas A}, issn = {2377-3766}, journal = {IEEE Robotics and Automation Letters}, number = {3}, pages = {1595--1602}, publisher = {Institute of Electrical and Electronics Engineers}, title = {{Revisiting the adversarial robustness-accuracy tradeoff in robot learning}}, doi = {10.1109/LRA.2023.3240930}, volume = {8}, year = {2023}, } @article{12705, abstract = {The elasticity of disordered and polydisperse polymer networks is a fundamental problem of soft matter physics that is still open. Here, we self-assemble polymer networks via simulations of a mixture of bivalent and tri- or tetravalent patchy particles, which result in an exponential strand length distribution analogous to that of experimental randomly cross-linked systems. After assembly, the network connectivity and topology are frozen and the resulting system is characterized. We find that the fractal structure of the network depends on the number density at which the assembly has been carried out, but that systems with the same mean valence and same assembly density have the same structural properties. Moreover, we compute the long-time limit of the mean-squared displacement, also known as the (squared) localization length, of the cross-links and of the middle monomers of the strands, showing that the dynamics of long strands is well described by the tube model. Finally, we find a relation connecting these two localization lengths at high density and connect the cross-link localization length to the shear modulus of the system.}, author = {Sorichetti, Valerio and Ninarello, Andrea and Ruiz-Franco, José and Hugouvieux, Virginie and Zaccarelli, Emanuela and Micheletti, Cristian and Kob, Walter and Rovigatti, Lorenzo}, issn = {1089-7690}, journal = {Journal of Chemical Physics}, number = {7}, publisher = {American Institute of Physics}, title = {{Structure and elasticity of model disordered, polydisperse, and defect-free polymer networks}}, doi = {10.1063/5.0134271}, volume = {158}, year = {2023}, } @article{12706, abstract = {Allometric settings of population dynamics models are appealing due to their parsimonious nature and broad utility when studying system level effects. Here, we parameterise the size-scaled Rosenzweig-MacArthur differential equations to eliminate prey-mass dependency, facilitating an in depth analytic study of the equations which incorporates scaling parameters’ contributions to coexistence. We define the functional response term to match empirical findings, and examine situations where metabolic theory derivations and observation diverge. The dynamical properties of the Rosenzweig-MacArthur system, encompassing the distribution of size-abundance equilibria, the scaling of period and amplitude of population cycling, and relationships between predator and prey abundances, are consistent with empirical observation. Our parameterisation is an accurate minimal model across 15+ orders of mass magnitude.}, author = {Mckerral, Jody C. and Kleshnina, Maria and Ejov, Vladimir and Bartle, Louise and Mitchell, James G. and Filar, Jerzy A.}, issn = {1932-6203}, journal = {PLoS One}, number = {2}, pages = {e0279838}, publisher = {Public Library of Science}, title = {{Empirical parameterisation and dynamical analysis of the allometric Rosenzweig-MacArthur equations}}, doi = {10.1371/journal.pone.0279838}, volume = {18}, year = {2023}, } @article{12707, abstract = {We establish precise right-tail small deviation estimates for the largest eigenvalue of real symmetric and complex Hermitian matrices whose entries are independent random variables with uniformly bounded moments. The proof relies on a Green function comparison along a continuous interpolating matrix flow for a long time. Less precise estimates are also obtained in the left tail.}, author = {Erdös, László and Xu, Yuanyuan}, issn = {1350-7265}, journal = {Bernoulli}, number = {2}, pages = {1063--1079}, publisher = {Bernoulli Society for Mathematical Statistics and Probability}, title = {{Small deviation estimates for the largest eigenvalue of Wigner matrices}}, doi = {10.3150/22-BEJ1490}, volume = {29}, year = {2023}, } @article{12708, abstract = {Self-organisation is the spontaneous emergence of spatio-temporal structures and patterns from the interaction of smaller individual units. Examples are found across many scales in very different systems and scientific disciplines, from physics, materials science and robotics to biology, geophysics and astronomy. Recent research has highlighted how self-organisation can be both mediated and controlled by confinement. Confinement is an action over a system that limits its units’ translational and rotational degrees of freedom, thus also influencing the system's phase space probability density; it can function as either a catalyst or inhibitor of self-organisation. Confinement can then become a means to actively steer the emergence or suppression of collective phenomena in space and time. Here, to provide a common framework and perspective for future research, we examine the role of confinement in the self-organisation of soft-matter systems and identify overarching scientific challenges that need to be addressed to harness its full scientific and technological potential in soft matter and related fields. By drawing analogies with other disciplines, this framework will accelerate a common deeper understanding of self-organisation and trigger the development of innovative strategies to steer it using confinement, with impact on, e.g., the design of smarter materials, tissue engineering for biomedicine and in guiding active matter.}, author = {Araújo, Nuno A.M. and Janssen, Liesbeth M.C. and Barois, Thomas and Boffetta, Guido and Cohen, Itai and Corbetta, Alessandro and Dauchot, Olivier and Dijkstra, Marjolein and Durham, William M. and Dussutour, Audrey and Garnier, Simon and Gelderblom, Hanneke and Golestanian, Ramin and Isa, Lucio and Koenderink, Gijsje H. and Löwen, Hartmut and Metzler, Ralf and Polin, Marco and Royall, C. Patrick and Šarić, Anđela and Sengupta, Anupam and Sykes, Cécile and Trianni, Vito and Tuval, Idan and Vogel, Nicolas and Yeomans, Julia M. and Zuriguel, Iker and Marin, Alvaro and Volpe, Giorgio}, issn = {1744-6848}, journal = {Soft Matter}, pages = {1695--1704}, publisher = {Royal Society of Chemistry}, title = {{Steering self-organisation through confinement}}, doi = {10.1039/d2sm01562e}, volume = {19}, year = {2023}, } @article{12709, abstract = {Given a finite set A ⊂ ℝ^d, let Cov_{r,k} denote the set of all points within distance r to at least k points of A. Allowing r and k to vary, we obtain a 2-parameter family of spaces that grow larger when r increases or k decreases, called the multicover bifiltration. Motivated by the problem of computing the homology of this bifiltration, we introduce two closely related combinatorial bifiltrations, one polyhedral and the other simplicial, which are both topologically equivalent to the multicover bifiltration and far smaller than a Čech-based model considered in prior work of Sheehy. Our polyhedral construction is a bifiltration of the rhomboid tiling of Edelsbrunner and Osang, and can be efficiently computed using a variant of an algorithm given by these authors as well. Using an implementation for dimension 2 and 3, we provide experimental results. Our simplicial construction is useful for understanding the polyhedral construction and proving its correctness.}, author = {Corbet, René and Kerber, Michael and Lesnick, Michael and Osang, Georg F}, issn = {1432-0444}, journal = {Discrete and Computational Geometry}, pages = {376--405}, publisher = {Springer Nature}, title = {{Computing the multicover bifiltration}}, doi = {10.1007/s00454-022-00476-8}, volume = {70}, year = {2023}, } @article{12710, abstract = {Surface curvature both emerges from, and influences the behavior of, living objects at length scales ranging from cell membranes to single cells to tissues and organs. The relevance of surface curvature in biology is supported by numerous experimental and theoretical investigations in recent years. In this review, first, a brief introduction to the key ideas of surface curvature in the context of biological systems is given and the challenges that arise when measuring surface curvature are discussed. Giving an overview of the emergence of curvature in biological systems, its significance at different length scales becomes apparent. On the other hand, summarizing current findings also shows that both single cells and entire cell sheets, tissues or organisms respond to curvature by modulating their shape and their migration behavior. Finally, the interplay between the distribution of morphogens or micro-organisms and the emergence of curvature across length scales is addressed with examples demonstrating these key mechanistic principles of morphogenesis. Overall, this review highlights that curved interfaces are not merely a passive by-product of the chemical, biological, and mechanical processes but that curvature acts also as a signal that co-determines these processes.}, author = {Schamberger, Barbara and Ziege, Ricardo and Anselme, Karine and Ben Amar, Martine and Bykowski, Michał and Castro, André P.G. and Cipitria, Amaia and Coles, Rhoslyn A. and Dimova, Rumiana and Eder, Michaela and Ehrig, Sebastian and Escudero, Luis M. and Evans, Myfanwy E. and Fernandes, Paulo R. and Fratzl, Peter and Geris, Liesbet and Gierlinger, Notburga and Hannezo, Edouard B and Iglič, Aleš and Kirkensgaard, Jacob J.K. and Kollmannsberger, Philip and Kowalewska, Łucja and Kurniawan, Nicholas A. and Papantoniou, Ioannis and Pieuchot, Laurent and Pires, Tiago H.V. and Renner, Lars D. and Sageman-Furnas, Andrew O. and Schröder-Turk, Gerd E. and Sengupta, Anupam and Sharma, Vikas R. and Tagua, Antonio and Tomba, Caterina and Trepat, Xavier and Waters, Sarah L. and Yeo, Edwina F. and Roschger, Andreas and Bidan, Cécile M. and Dunlop, John W.C.}, issn = {1521-4095}, journal = {Advanced Materials}, number = {13}, publisher = {Wiley}, title = {{Curvature in biological systems: Its quantification, emergence, and implications across the scales}}, doi = {10.1002/adma.202206110}, volume = {35}, year = {2023}, } @article{12719, abstract = {Background Epigenetic clocks can track both chronological age (cAge) and biological age (bAge). The latter is typically defined by physiological biomarkers and risk of adverse health outcomes, including all-cause mortality. As cohort sample sizes increase, estimates of cAge and bAge become more precise. Here, we aim to develop accurate epigenetic predictors of cAge and bAge, whilst improving our understanding of their epigenomic architecture. Methods First, we perform large-scale (N = 18,413) epigenome-wide association studies (EWAS) of chronological age and all-cause mortality. Next, to create a cAge predictor, we use methylation data from 24,674 participants from the Generation Scotland study, the Lothian Birth Cohorts (LBC) of 1921 and 1936, and 8 other cohorts with publicly available data. In addition, we train a predictor of time to all-cause mortality as a proxy for bAge using the Generation Scotland cohort (1214 observed deaths). For this purpose, we use epigenetic surrogates (EpiScores) for 109 plasma proteins and the 8 component parts of GrimAge, one of the current best epigenetic predictors of survival. We test this bAge predictor in four external cohorts (LBC1921, LBC1936, the Framingham Heart Study and the Women’s Health Initiative study). Results Through the inclusion of linear and non-linear age-CpG associations from the EWAS, feature pre-selection in advance of elastic net regression, and a leave-one-cohort-out (LOCO) cross-validation framework, we obtain cAge prediction with a median absolute error equal to 2.3 years. Our bAge predictor was found to slightly outperform GrimAge in terms of the strength of its association to survival (HRGrimAge = 1.47 [1.40, 1.54] with p = 1.08 × 10−52, and HRbAge = 1.52 [1.44, 1.59] with p = 2.20 × 10−60). Finally, we introduce MethylBrowsR, an online tool to visualise epigenome-wide CpG-age associations. Conclusions The integration of multiple large datasets, EpiScores, non-linear DNAm effects, and new approaches to feature selection has facilitated improvements to the blood-based epigenetic prediction of biological and chronological age.}, author = {Bernabeu, Elena and Mccartney, Daniel L. and Gadd, Danni A. and Hillary, Robert F. and Lu, Ake T. and Murphy, Lee and Wrobel, Nicola and Campbell, Archie and Harris, Sarah E. and Liewald, David and Hayward, Caroline and Sudlow, Cathie and Cox, Simon R. and Evans, Kathryn L. and Horvath, Steve and Mcintosh, Andrew M. and Robinson, Matthew Richard and Vallejos, Catalina A. and Marioni, Riccardo E.}, issn = {1756-994X}, journal = {Genome Medicine}, publisher = {Springer Nature}, title = {{Refining epigenetic prediction of chronological and biological age}}, doi = {10.1186/s13073-023-01161-y}, volume = {15}, year = {2023}, } @inbook{12720, abstract = {Here we describe the in vivo DNA assembly approach, where molecular cloning procedures are performed using an E. coli recA-independent recombination pathway, which assembles linear fragments of DNA with short homologous termini. This pathway is present in all standard laboratory E. coli strains and, by bypassing the need for in vitro DNA assembly, allows simplified molecular cloning to be performed without the plasmid instability issues associated with specialized recombination-cloning bacterial strains. The methodology requires specific primer design and can perform all standard plasmid modifications (insertions, deletions, mutagenesis, and sub-cloning) in a rapid, simple, and cost-efficient manner, as it does not require commercial kits or specialized bacterial strains. Additionally, this approach can be used to perform complex procedures such as multiple modifications to a plasmid, as up to 6 linear fragments can be assembled in vivo by this recombination pathway. Procedures generally require less than 3 h, involving PCR amplification, DpnI digestion of template DNA, and transformation, upon which circular plasmids are assembled. In this chapter we describe the requirements, procedure, and potential pitfalls when using this technique, as well as protocol variations to overcome the most common issues.}, author = {Arroyo-Urea, Sandra and Watson, Jake and García-Nafría, Javier}, booktitle = {DNA Manipulation and Analysis}, editor = {Scarlett, Garry}, isbn = {978-1-0716-3003-7}, issn = {1940-6029}, pages = {33--44}, publisher = {Springer Nature}, title = {{Molecular Cloning Using In Vivo DNA Assembly}}, doi = {10.1007/978-1-0716-3004-4_3}, volume = {2633}, year = {2023}, } @article{12723, abstract = {Lead halide perovskites enjoy a number of remarkable optoelectronic properties. To explain their origin, it is necessary to study how electromagnetic fields interact with these systems. We address this problem here by studying two classical quantities: Faraday rotation and the complex refractive index in a paradigmatic perovskite CH3NH3PbBr3 in a broad wavelength range. We find that the minimal coupling of electromagnetic fields to the k⋅p Hamiltonian is insufficient to describe the observed data even on the qualitative level. To amend this, we demonstrate that there exists a relevant atomic-level coupling between electromagnetic fields and the spin degree of freedom. This spin-electric coupling allows for quantitative description of a number of previous as well as present experimental data. In particular, we use it here to show that the Faraday effect in lead halide perovskites is dominated by the Zeeman splitting of the energy levels and has a substantial beyond-Becquerel contribution. Finally, we present general symmetry-based phenomenological arguments that in the low-energy limit our effective model includes all basis coupling terms to the electromagnetic field in the linear order.}, author = {Volosniev, Artem and Shiva Kumar, Abhishek and Lorenc, Dusan and Ashourishokri, Younes and Zhumekenov, Ayan A. and Bakr, Osman M. and Lemeshko, Mikhail and Alpichshev, Zhanybek}, issn = {1079-7114}, journal = {Physical Review Letters}, keywords = {General Physics and Astronomy}, number = {10}, publisher = {American Physical Society}, title = {{Spin-electric coupling in lead halide perovskites}}, doi = {10.1103/physrevlett.130.106901}, volume = {130}, year = {2023}, } @article{12724, abstract = {We use general symmetry-based arguments to construct an effective model suitable for studying optical properties of lead halide perovskites. To build the model, we identify an atomic-level interaction between electromagnetic fields and the spin degree of freedom that should be added to a minimally coupled k⋅p Hamiltonian. As a first application, we study two basic optical characteristics of the material: the Verdet constant and the refractive index. Beyond these linear characteristics of the material, the model is suitable for calculating nonlinear effects such as the third-order optical susceptibility. Analysis of this quantity shows that the geometrical properties of the spin-electric term imply isotropic optical response of the system, and that optical anisotropy of lead halide perovskites is a manifestation of hopping of charge carriers. To illustrate this, we discuss third-harmonic generation.}, author = {Volosniev, Artem and Shiva Kumar, Abhishek and Lorenc, Dusan and Ashourishokri, Younes and Zhumekenov, Ayan and Bakr, Osman M. and Lemeshko, Mikhail and Alpichshev, Zhanybek}, issn = {2469-9969}, journal = {Physical Review B}, number = {12}, publisher = {American Physical Society}, title = {{Effective model for studying optical properties of lead halide perovskites}}, doi = {10.1103/physrevb.107.125201}, volume = {107}, year = {2023}, } @inproceedings{12735, abstract = {Asynchronous programming has gained significant popularity over the last decade: support for this programming pattern is available in many popular languages via libraries and native language implementations, typically in the form of coroutines or the async/await construct. Instead of programming via shared memory, this concept assumes implicit synchronization through message passing. The key data structure enabling such communication is the rendezvous channel. Roughly, a rendezvous channel is a blocking queue of size zero, so both send(e) and receive() operations wait for each other, performing a rendezvous when they meet. To optimize the message passing pattern, channels are usually equipped with a fixed-size buffer, so sends do not suspend and put elements into the buffer until its capacity is exceeded. This primitive is known as a buffered channel. This paper presents a fast and scalable algorithm for both rendezvous and buffered channels. Similarly to modern queues, our solution is based on an infinite array with two positional counters for send(e) and receive() operations, leveraging the unconditional Fetch-And-Add instruction to update them. Yet, the algorithm requires non-trivial modifications of this classic pattern, in order to support the full channel semantics, such as buffering and cancellation of waiting requests. We compare the performance of our solution to that of the Kotlin implementation, as well as against other academic proposals, showing up to 9.8× speedup. To showcase its expressiveness and performance, we also integrated the proposed algorithm into the standard Kotlin Coroutines library, replacing the previous channel implementations.}, author = {Koval, Nikita and Alistarh, Dan-Adrian and Elizarov, Roman}, booktitle = {Proceedings of the ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming}, isbn = {9798400700156}, location = {Montreal, QC, Canada}, pages = {107--118}, publisher = {Association for Computing Machinery}, title = {{Fast and scalable channels in Kotlin Coroutines}}, doi = {10.1145/3572848.3577481}, year = {2023}, } @misc{12736, abstract = {Although a wide variety of handcrafted concurrent data structures have been proposed, there is considerable interest in universal approaches (Universal Constructions or UCs) for building concurrent data structures. UCs (semi-)automatically convert a sequential data structure into a concurrent one. The simplest approach uses locks [3, 6] that protect a sequential data structure and allow only one process to access it at a time. However, the resulting data structure is blocking. Most work on UCs instead focuses on obtaining non-blocking progress guarantees such as obstruction-freedom, lock-freedom or wait-freedom. Many non-blocking UCs have appeared. Key examples include the seminal wait-free UC [2] by Herlihy, a NUMA-aware UC [10] by Yi et al., and an efficient UC for large objects [1] by Fatourou et al.}, author = {Aksenov, Vitaly and Brown, Trevor A and Fedorov, Alexander and Kokorin, Ilya}, booktitle = {Proceedings of the ACM SIGPLAN Symposium on Principles and Practice of Parallel Programming}, isbn = {9798400700156}, location = {Montreal, QB, Canada}, pages = {438--440}, publisher = {Association for Computing Machinery}, title = {{Unexpected scaling in path copying trees}}, doi = {10.1145/3572848.3577512}, year = {2023}, }