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Collective particle transport across periodic energy landscapes is ubiquitously present in many condensed matter systems spanning from vortices in high-temperature superconductors, frictional atomic sliding, driven skyrmions to biological and active matter. Here we report the emergence of fast solitons propagating against a rotating optical landscape. These experimentally observed solitons are stable cluster waves that originate from a coordinated particle exchange process which occurs when the number of trapped microparticles exceeds the number of potential wells. The size and speed of individual solitons rapidly increase with the particle diameter as predicted by theory and confirmed by numerical simulations. We show that when several solitons coexist, an effective repulsive interaction can stabilize their propagation along the periodic potential. Our experiments demonstrate a generic mechanism for cluster-mediated transport with potential applications to condensed matter systems on different length scales.

We propose a simulation method for Brownian dynamics of hard rods in one dimension for arbitrary continuous external force fields. It is an event-driven procedure based on the fragmentation and mergers of clusters formed by particles in contact. It allows one to treat particle interactions in addition to the hard-sphere exclusion as long as the corresponding interaction forces are continuous functions of the particle coordinates. We furthermore develop a treatment of sticky hard spheres as described by Baxter's contact interaction potential., Comment: 12 pages, 7 figures

Introduction The aim of this multicenter prospective study was to analyze the outcomes of bone lengthening by external fixator associated with flexible intramedullary nailing (FIN) in acquired limb length discrepancy (LLD). Hypothesis Hydroxyapatite (HA)-coated FIN enables reduced External Fixation Index in limb lengthening for acquired leg length discrepancies in comparison to non-HA-coated FIN. Material and methods This study included 54 patients (mean age, 17.9 years) operated on for femoral or tibial lengthening by combined technique (External fixator with FIN) for acquired length discrepancy. Titanium non-HA-coated FIN (29 cases) or HA-coated FIN (25 cases) were used. The factors that might influence external fixation index, complication occurrence and outcome were analyzed: age, amount of lengthening, nail diameter, HA-coating vs. non-HA-coated nails. Results The mean External Fixation Indexes (EFI) of groups compared for non-HA-coated nails vs. HA-coated nails were not significantly different: 26.5 d/cm and 27.2 d/cm in femoral lengthening and 34.9 d/cm and 31.7 d/cm in tibial lengthening. Positive correlation between the “nail diameter/inner distance between cortices at osteotomy site” ratio and EFI in tibial lengthening was revealed (p = 0.034). The nail types and the “nail diameter/medullary canal diameter” ratio interact and have significant simultaneous effect on EFI in femoral lengthening (p = 0.021). Discussion The results of this study revealed no differences with regards to EFI using HA-coated or non-HA-coated titanium FIN in lengthening for acquired leg-length discrepancies. Combined technique allowed reduced EFI and avoided major complications. Both non-HA-nail and HA-coated nail lengthening provided good and excellent outcomes. Level of evidence III; (controlled trial without randomization) prospective comparative study.

Hybridization and introgression are very common among freshwater fishes due to the dynamic nature of hydrological landscapes. Cyclic patterns of allopatry and secondary contact provide numerous opportunities for interspecific gene flow, which can lead to discordant paths of evolution for mitochondrial and nuclear genomes. Here, we used double digest restriction-site associated DNA sequencing (ddRADseq) to obtain a genome-wide single nucleotide polymorphism (SNP) dataset comprehensive for allThymallus (Salmonidae)species to infer phylogenetic relationships and evaluate potential recent and historical gene flow among species. The newly obtained nuclear phylogeny was largely concordant with a previously published mitogenome-based topology but revealed a few cyto-nuclear discordances. These incongruencies primarily involved the placement of internal nodes rather than the resolution of species, except for one European species where anthropogenic stock transfers are thought to be responsible for the observed pattern. The analysis of four contact zones where multiple species are found revealed a few cases of mitochondrial capture and limited signals of nuclear introgression. Interestingly, the mechanisms restricting interspecific gene flow might be distinct; while in zones of secondary contact, small-scale physical habitat separation appeared as a limiting factor, biologically based reinforcement mechanisms are presumed to be operative in areas where species presumably evolved in sympatry. Signals of historical introgression were largely congruent with the routes of species dispersal previously inferred from mitogenome data. Overall, the ddRADseq dataset provided a robust phylogenetic reconstruction of the genus Thymallus including new insights into historical hybridization and introgression, opening up new questions concerning their evolutionary history.

Solitons are commonly known as waves that propagate without dispersion. Here we show that they can occur for driven overdamped Brownian dynamics of hard spheres in periodic potentials at high densities. The solitons manifest themselves as periodic sequences of different assemblies of particles moving in the limit of zero noise, where transport of single particles is not possible. They give rise to particle currents at even low temperature that appear in band-like structures around certain hard-sphere diameters. At high temperatures, the band-like structures are washed out by the noise, but the particle transport is still dominated by the solitons. All these predicted features should occur in a broad class of periodic systems and are amenable to experimental tests., 6 pages, 4 figures plus supplemental material with 7 pages and 1 figure; 5 ancillary movie files

Structural and technological aspects of obtaining composite materials based on polytetrafluoroethylene are considered. It is shown that due to the manifestation of the inertness of the components in the processes of interfacial interaction with an increase in the degree of filling, within the framework of the traditional technological paradigm, a structural paradox is realized. This paradox consists in a proportional decrease in the tensile strength parameter of fluorocomposites with an increase in their degree of filling. Based on the concept of energy and technological compliance of components, technological principles for eliminating the negative impact of the structural paradox by controlling the structure of fluorine composites at various levels of organization: molecular, supramolecular, phase and interfacial are proposed. Efficient methods have been developed for manufacturing products from highly filled fluorine composites containing 25–35% (wt.) carbon fiber and having parameters of stress-strain characteristics that are 1.5–2.0 times higher than the parameters of the analogues "Flubon", "Fluvis".

In crowded systems, particle currents can be mediated by propagating collective excitations which are generated as rare events, are localized and have a finite lifetime. The theoretical description of such excitations is hampered by the problem of identifying complex many-particle transition states, calculation of their free energies, and the evaluation of propagation mechanisms and velocities. Here we show that these problems can be tackled for a highly jammed system of hard spheres in a periodic potential. We derive generation rates of collective excitations, their anomalously high velocities, explain the occurrence of an apparent jamming transition and its strong dependence on the system size. The particle currents follow a scaling behavior, where for small systems the current is proportional to the generation rate and for large systems given by the geometric mean of the generation rate and velocity. Our theoretical approach is widely applicable to dense nonequilibrium systems in confined geometries. It provides new perspectives for studying dynamics of collective excitations in experiments., 23 pages, 9 figures

In typical computer system design flows, hardware microarchitecture is commonly considered a dynamically developing domain, where abstract mechanisms remain mostly in conceptual form and exhibit poor source code reuse in designs. However, many important basic mechanisms appear to be pervasive and persistent. This paper summarizes original efforts to propose generic implementations of microarchitectural mechanisms for in-order and out-of-order microarchitectures and various demo designs based on these implementations. The basic EDA components proposed for this design approach are “Kernel IP (KIP) cores”—open-source collection of programmable hardware generators inferred from microarchitectural templates. KIP cores feasibility for their role is demonstrated from the viewpoints of abstract representation of microarchitectural mechanisms, support of functional differentiation of designs, and generic optimizations. Experimental designing according to this approach has shown useful separation of concerns in hardware design activities, lower design effort, and increased formalization and code reuse.