Propagation History Research Articles

Using Constraint Propagation to Bound Linear Programs

We present an approach to compute bounds on the optimal value of linear programs based on constraint propagation. Given a feasible dual solution, we apply constraint propagation to the complementary slackness conditions and, if propagation succeeds to prove these conditions infeasible, the infeasibility certificate (in the sense of Farkas’ lemma) is reconstructed from the propagation history. This certificate is a dual-improving direction, which allows us to improve the bound. As constraint propagation need not always detect infeasibility of a linear inequality system, the method is not guaranteed to converge to a global solution of the linear program but only to an upper bound, whose tightness depends on the structure of the program and the used propagation method. The approach is suited for large sparse linear programs (such as LP relaxations of combinatorial optimization problems), for which the classical LP algorithms may be infeasible, if only for their super-linear space complexity. The approach can be seen as a generalization of the Virtual Arc Consistency (VAC) algorithm to bound the LP relaxation of the Weighted CSP (WCSP). We newly apply it to the LP relaxation of the Weighted Max-SAT problem, experimentally showing that the obtained bounds are often not far from optima of the relaxation and proving that they are exact for known tractable subclasses of Weighted Max-SAT.

Dynamical System Approach and Thermodynamical Perspective of Hořava‐Lifshitz Gravity

AbstractThe authors have examined a Friedmann Robertson Walker cosmological model in Hořava‐Lifshitz gravity by using a dynamical system approach. A set of autonomous equations is derived and their solutions are calculated. The critical points from these equations and find the characteristics values with the analysis of the physical interpretation of the phase space for this system are assessed. Three stable critical points are found and the values of the physical parameters and the scale factor's expressions at each critical points are displayed in Tables 1, 2, and 3. A hybrid scale factor to develop the model, which results in a phase transition from deceleration to acceleration is used. The suitable values of the parameters are governed by applying the Monte Chain Monte Carlo method technique to the Hubble 46 and joint Hubble 46 and Baryon Acoustic Oscillations 15 datasets. In contrast to the negative behavior of pressure, the positive behavior of energy density and illustrate the Universe's acceleration epoch and the model is represented by the EoS parameter . The authors investigated that the energy conditions and their model violates the strong energy condition. Utilizing diagnostic test, it is found that the model represents phantom behavior. The thermodynamical perspective for the model is also examined. The model accurately explained the Universe's propagation history and fits well with contemporary cosmic data.

Longitudinal seismic analysis for underground structures passing through soft-hard strata based on periodic stratum deformation

Poor geological conditions, e.g., soft and hard strata, have a significant impact on the seismic response of underground structures. In this study, a series of longitudinal seismic analysis for underground structures passing through soft-hard strata were conducted based on the concept of periodic stratum deformation. Firstly, the analytical expressions of stratum deformation in soft-hard strata at the oblique incidence of plan P-, and S- wave were obtained via decomposing the stratum deformation into the reflected- and transmitted wave fields. Then, the wave propagation history in soft-hard strata in the time domain was transformed into strata deformation in a period via introducing concept of the periodic stratum deformation. Base on the proposed expressions, a self-developed Python program was implemented into finite element software ABAQUS to establish seismic analysis model and to calculate the longitudinal seismic response of underground structures. Finally, example analyses were conducted to study the influence of plane P- and S- wave, wave velocity ratio of soft and hard media, as well as incident wave angle on the seismic response of underground structures located in soft- hard strata. This study may provide a reference for seismic design of underground structures located in soft- hard strata.

Three-dimensional buoyant hydraulic fractures: finite-volume release

In impermeable media, a hydraulic fracture can continue expanding even without additional fluid injection if its volume exceeds the limiting volume of a hydrostatically loaded radial fracture. This limit depends on the mechanical properties of the surrounding solid and the density contrast between the fluid and the solid. We show that two dimensionless numbers characterize self-sustained fracture growth. The first is a buoyancy factor that compares the total released volume to the volume of a hydrostatically loaded radial fracture to determine whether buoyant growth occurs. The second number is the dimensionless viscosity of a radial fracture when buoyant effects become of order one. Notably, this dimensionless viscosity depends on the rate at which the fluid volume is released, indicating that both the total volume and release history impact self-sustained buoyant growth. We identify six well-defined propagation histories based on these two dimensionless numbers. Their growth evolves between distinct limiting regimes of radial and buoyant propagation, resulting in different fracture shapes. Notably, our findings reveal two growth rates depending on the dominant energy dissipation mechanism (viscous flow versus fracture creation) in the fracture head. For finite values of material toughness, the toughness-dominated limit represents a late-time solution for all fractures in growth rate and head shape (possibly reached only at a very late time). The viscosity-dominated limit can appear at intermediate times. Our three-dimensional simulations confirm the predicted scalings. This contribution highlights the importance of the entire propagation and release history for accurate analysis of buoyant hydraulic fractures.

Pangenome analyses reveal impact of transposable elements and ploidy on the evolution of potato species

Potato (Solanum sp., family Solanaceae) is the most important noncereal food crop globally. It has over 100 wild relatives in the Solanum section Petota, which features species with both sexual and asexual reproduction and varying ploidy levels. A pangenome of Solanum section Petota composed of 296 accessions was constructed including diploids and polyploids compared via presence/absence variation (PAV). The Petota core (genes shared by at least 97% of the accessions) and shell genomes (shared by 3 to 97%) are enriched in basic molecular and cellular functions, while the cloud genome (genes present in less than 3% of the member accessions) showed enrichment in transposable elements (TEs). Comparison of PAV in domesticated vs. wild accessions was made, and a phylogenetic tree was constructed based on PAVs, grouping accessions into different clades, similar to previous phylogenies produced using DNA markers. A cladewise pangenome approach identified abiotic stress response among the core genes in clade 1+2 and clade 3, and flowering/tuberization among the core genes in clade 4. The TE content differed between the clades, with clade 1+2, which is composed of species from North and Central America with reproductive isolation from species in other clades, having much lower TE content compared to other clades. In contrast, accessions with in vitro propagation history were identified and found to have high levels of TEs. Results indicate a role for TEs in adaptation to new environments, both natural and artificial, for Solanum section Petota.

Diffractive Theory Study of Twisted Light’s Evolution during Phase-Only OAM Manipulations

Twisted light, or orbital angular momentum (OAM) carrying beams or photons, is a pillar of structured photonics, a booming subfield of modern optics. The generation and transformation of twisted light, which lie with coupling topological charges into target light’s wavefunctions, are usually performed by phase-only OAM manipulations. The practical twisted lights, however, obtained by this method are actually noneigen modes of free space, leading to an evolution through the diffractive propagation. Here, we present a general theoretical frame for accurately describing this evolution. Based on the theory, the whole diffractive propagation history in a typical OAM-manipulation loop, converting Gaussian light into a twisted one and then reconverting back, is demonstrated via a set of exact analytical solutions. These results provide a powerful tool for analyzing the transverse profiles of twisted light through the diffractive evolution, as a guideline for studying the science of structured light, which would provide guidelines for research studies in nonlinear optics and high-dimensional quantum information technology based on OAM-degree of freedom.

SRRS: A blockchain fast propagation protocol based on non-Markovian process

The blockchain technology that underlies many cryptocurrencies, such as Bitcoin and Ethereum, is demanded to raise for more efficient transactions. Thus, in the last decade, many solutions have been proposed to improve the propagation of blocks. Motivated by SRRS (social reinforcement rumor spreading), we propose a blockchain fast propagation protocol named SRRS protocol based on a non-Markovian process, where the verification and transmission of a block depend on its propagation history. The simulated experimental results show that our protocol can significantly accelerate the propagation of blocks. Compared with existing major solutions, our protocol does not change the main procedure of Bitcoin and the block data structure, which is a huge advantage for practical applications. Moreover, employing the theories of complex networks and percolation, we develop a method of theoretical analysis, which can find the optimal setting of our protocol.

Atrial fibrillation mechanisms before and after pulmonary vein isolation characterized by noncontact charge density mapping.

The interaction of the pulmonary vein (PV) and putative nonpulmonary triggers of atrial fibrillation (AF) remains unclear and has yet to translate into patient-tailored ablation strategies. The purpose of this study was to use noncontact mapping to detail the global conduction patterns in paroxysmal and persistent AF and how they are modified during PV ablation. Forty patients during AF ablation underwent mapping using a noncontact catheter (AcQMap, Acutus Medical, Inc., Carlsbad, CA) before and after PV isolation (PVI). Propagation history maps were analyzed postprocedure for each patient to categorize conduction patterns into focal, organized reentrant, and disorganized patterns (F-Patterns, O-Patterns, and D-Patterns, respectively). Activation patterns identified by using a noncontact mapping system can be subclassified from 3 main patterns into subtypes (macroreentrant and localized reentrant [MR and LR] subtypes and disorganized 1 and disorganized 2 [D1 and D2] subtypes). Persistent AF demonstrated more D-Patterns and less O-Patterns and F-Patterns than did paroxysmal AF. In addition, patients with PAF inducible after PVI demonstrated a higher region number and higher prevalence of MR subtypes than did those noninducible. PVs remained the critical region and included almost one-third of all patterns across any AF types. PVI was effective to eliminate PV-related functional phenotypes and affected recurrence with other patterns. Activation patterns identified using AcQMap can be classified into 3 main patterns (F-Patterns, O-Patterns, and D-Patterns) as well as subtypes (MR and LR subtypes and D1 and D2 subtypes). PerAF was different from PAF in demonstrating a higher region number and higher prevalence of D-Patterns but a lower region number and lower prevalence of O-Patterns and F-Patterns.

Female Sex Ratio Bias in Extended Growth Hatchery Walleye Fingerlings Produced in Wisconsin

AbstractSex differentiation in teleost fish is complex and often dictated by genetics, environmental conditions, and population density during critical embryonic/larval development periods. Walleye Sander vitreus have a long propagation and stocking history, and sex ratios of hatchery‐reared Walleye have been variable, typically skewed towards males, and potentially influenced by temperature. In contrast to previous fry and small fingerling Walleye stocking in Wisconsin water bodies, the Wisconsin Walleye Initiative of 2013 focused on the production of extended growth Walleye fingerlings (EGW) stocked out in fall under the assumption of greater survivorship and in response to observed declines in Walleye natural recruitment. Observed sex ratios of adult Walleye in a stocked northern Wisconsin lake chain were suggestive of EGW sex ratios skewed towards females. This lake chain has been under rehabilitation and an aggressive EGW stocking regime due to prolonged Walleye natural recruitment failures. To test whether imbalances in EGW were occurring, we collected 30 EGW from one Wisconsin hatchery in 2019 and about 50 EGW from each of three Wisconsin hatcheries in 2020 to histologically determine sex ratios. In 2019, EGW were about 97% female. In 2020, the percentage of females in hatchery samples ranged from 60% to 100%. Nonfemales in 2019 and 2020 were all undifferentiated. Our results suggest that EGW raised in Wisconsin under similar incubation and rearing protocols may be skewed towards females. If sex ratios of EGW are skewed towards females, the use of EGW may hinder efforts to rehabilitate natural recruitment. A deductive experimental and observational framework will be used to test for mechanism(s) influencing the high percentage of females in the hatchery product to inform protocols to better balance sex ratios.

準静的強制引張作用漸増下のき裂進展加速過程の実験・数値シミュレーション

Crack propagation velocities depend on various mechanical factors and others. Propagating crack acceleration is not special phenomenon in material fracture problems, it can be caused under simple quasi-static tensile loading. However, the general theory to determine crack propagating velocity is not established. In this study, generation phase simulation is demonstrated to discuss mechanism for crack accelerations. Crack propagation history, crack propagation start timing and constrained displacement conditions in the numerical analysis are based on the experimental fracture tests. Crack propagation behavior is treated by the moving finite element method. J integral are evaluated in the numerical simulation.

Continuous temporal network embedding by modeling neighborhood propagation process

Network embedding has become the focal point of increasing research interests in academic and industrial domains. Temporal networks are evolved by adding nodes and edges sequentially, which should be regarded as neighborhood propagation processes driven by chronological interactive events between nodes at arbitrary time granularity. In this scenario, both the occurrence times and connected nodes of interactive events are the key factors for embedding. Existing models of neighborhood propagation process focus on conventional temporal point process modeled by manual parametric forms of conditional intensity function, which merely measures the event occurrence probability at occurrence time. However, modeling event propagation without considering the connections of nodes in the network is inaccurate, requiring further research to capture both occurrence times and target nodes for temporal network embedding. In this paper, we propose a point process-based continuous temporal network embedding method by modeling neighborhood propagation process, named NPPCTNE, where the neighborhood propagation history is embedded into a hidden vector to jointly model the node and time of each interactive event. For propagation node prediction, the generating process of the next target node is simulated respectively by transient and steady-state responses to aggregate the long-term and short-term propagation effects of the continuous network system. For propagation time prediction, an intensity-free temporal point process is applied, which directly estimates the generative time probability distribution of the propagation sequence to learn the whole evolution process of the temporal network. Experiments on four real-world datasets show the efficacy of our model compared to state-of-the-arts.

Tracking Knowledge Propagation Across Wikipedia Languages

In this paper, we present a dataset of inter-language knowledge propagation in Wikipedia. Covering the entire 309 language editions and 33M articles, the dataset aims to track the full propagation history of Wikipedia concepts, and allow follow-up research on building predictive models of them. For this purpose, we align all the Wikipedia articles in a language-agnostic manner according to the concept they cover, which results in 13M propagation instances. To the best of our knowledge, this dataset is the first to explore the full inter-language propagation at a large scale. Together with the dataset, a holistic overview of the propagation and key insights about the underlying structural factors are provided to aid future research. For example, we find that although long cascades are unusual, the propagation tends to continue further once it reaches more than four language editions. We also find that the size of language editions is associated with the speed of propagation. We believe the dataset not only contributes to the prior literature on Wikipedia growth but also enables new use cases such as edit recommendation for addressing knowledge gaps, detection of disinformation, and cultural relationship analysis.

Seismic characteristics of polygonal fault systems in the Great South Basin, New Zealand

Abstract A well-developed multi-tier polygonal fault system is located in the Great South Basin offshore New Zealand’s South Island. The system has been characterised using a high-quality three-dimensional seismic survey tied to available exploration boreholes using regional two-dimensional seismic data. In this study area, two polygonal fault intervals are identified and analysed, Tier 1 and Tier 2. Tier 1 coincides with the Tucker Cove Formation (Late Eocene) with small polygonal faults. Tier 2 is restricted to the Paleocene-to-Late Eocene interval with a great number of large faults. In map view, polygonal fault cells are outlined by a series of conjugate pairs of normal faults. The polygonal faults are demonstrated to be controlled by depositional facies, specifically offshore bathyal deposits characterised by fine-grained clays, marls and muds. Fault throw analysis is used to understand the propagation history of the polygonal faults in this area. Tier 1 and Tier 2 initiate at about Late Eocene and Early Eocene, respectively, based on their maximum fault throws. A set of three-dimensional fault throw images within Tier 2 shows that maximum fault throws of the inner polygonal fault cell occurs at the same age, while the outer polygonal fault cell exhibits maximum fault throws at shallower levels of different ages. The polygonal fault systems are believed to be related to the dewatering of sedimentary formation during the diagenesis process. Interpretation of the polygonal fault in this area is useful in assessing the migration pathway and seal ability of the Eocene mudstone sequence in the Great South Basin.

Mechanical stratigraphy and layer-bound normal faulting in the Upper Cretaceous Niobrara Formation, Wattenberg Field, Colorado

Layer-bound normal faults are pervasive within the very fine-grained rocks of the Upper Cretaceous Niobrara and Carlile formations in the Denver Basin. 3-D seismic and well log interpretation reveal a complex, segmented fault system that is divided into two discrete tiers: an upper tier located in the Pierre Shale, and a lower tier located in the Niobrara Formation. 3-D fault throw analysis shows maximum throw near the top of the Niobrara Formation with steep, asymmetrical throw gradient down section in the lower Niobrara and Carlile formations. Faults are laterally well-connected in the upper Niobrara Formation and commonly form linear arrays of linked graben systems. In contrast, faults deeper in the stratigraphic section that offset the Carlile and Greenhorn formations are more segmented and commonly form half grabens (as opposed to full, fault-bound grabens). In cross-section, fault planes measured from seismic have a general dip of 45°. However, close inspection reveals that faults consistently change dip angle as they pass through the lower Niobrara Formation, refracting from ~55° to ~35° through the Niobrara C Marl, then back up to ~50° in the Carlile and Greenhorn formations. The fault dip refraction produces a contractional step or bend in the fault plane associated with the lower dip segments. This geometry is investigated further with horizontal image logs and other borehole data to reveal a kinematic relationship between fault dip angle and mechanical stratigraphy. Field examples of normal faults that cut mechanically layered rock help better understand these complex fault geometries and provide reasonable inferences to their development and propagation history. In summary, it is argued that the mechanically layered nature of the Niobrara and Carlile formations is responsible for many of the fault characteristics described and provides valuable insight into understanding the fault system

Investigating thrust-fault growth and segment linkage using displacement distribution analysis in the active Duzhanzi thrust fault zone, Northern Tian Shan of China

Few studies investigate the detailed character of thrust-fault population or their along-strike fault-displacement patterns. Our study presents new displacement-length data collected from well-exposed thrust faults within the Dushanzi Thrust Fault Zone (DTFZ), an active thrust fault-fold system in the Northern Tianshan of China. Numerous surface-rupturing thrust faults cut through upper Quaternary glacial outwash terraces and younger alluvial fans. Based on 0.5 m-resolution LiDAR-derived DEMs, we measured along-strike displacement and lengths of ~30 fault strands to construct a three-dimensional deformation field recorded by these deformed marker surfaces. Three fault segments constitute the DTFZ, and each presents different geometric structures and displacement patterns. Through detailed analysis of the displacement distribution and geometrical attributes of thrust faults, we constrain the growth and propagation history of faults and of the systems that they form. The scaling relationship between maximum displacement (Dmax) and fault length (L) measured from thrust faults within the DTFZ displays similar linear scaling to other thrust faults, but different Dmax/L ratios due to underestimated displacement of the DTFZ. Two conceptual models: a single-fault model and segment-linkage model are explored to explain the growth of faults or fault systems and the changes of Dmax/L ratios during fault evolution.

Captive Propagation and Early Life History of the Yazoo Darter (Etheostoma raneyi)

Captive propagation of fishes to achieve a variety of management goals is common and is increasingly included in recovery plans for imperiled species. Here, we present a protocol for the captive propagation of Etheostoma raneyi (Yazoo Darter) and summarize early life-history information. From 9 males and 17 females, we collected >1000 larvae, of which >83% survived to the juvenile stage. Water temperature during spawning was 15.6–21 °C and larval production peaked at 17.2–20.6 °C. Spawning abruptly ceased when daily high water temperatures exceeded 21 °C for 3 consecutive days. Newly hatched larvae were able to swim vigorously, were pelagic, and were about 4.4–4.5 mm total length (TL). Compared to other darter species, the Yazoo Darter is among the easiest to propagate, and the protocol presented should be suitable to meet most management goals. The protocol also provides a sound basis for the development of species-specific captive-propagation techniques for ≥17 closely related and imperiled snubnose darters.

Propagation history ranking in social networks: A causality-based approach

Information diffusion is one of the most important issues in social network analysis. Unlike most existing works, which either rely on network topology or node profiles, this study focuses on the diffusion itself, i.e., the recorded propagation histories. These histories are the evidence of diffusion and can be used to explain to users what happened in their networks. However, these histories can quickly grow in size and complexity, limiting their capacity to be intuitively understood. To reduce this information overload, in this paper we present the problem of propagation history ranking. The goal is to rank participant edges/nodes by their contribution to the diffusion. We first discuss and adapt a causal measure, Difference of Causal Effects (DCE), as the ranking criterion. Then, to avoid the complex calculation of DCE, we propose two integrated ranking strategies by adopting two indicators. One is responsibility, which captures the necessity aspect of causal effects. We further give an approximate algorithm, which could guarantee a feasible solution, for this indicator. The other is capability, which captures the sufficiency aspect of causal effects. Finally, promising experimental results are presented to verify the feasibility of the proposed ranking strategies.

The dynamic crack propagation behavior of mode I interlaminar crack in unidirectional carbon/epoxy composites

The dynamic propagation behavior of the mode I interlaminar crack in unidirectional carbon/epoxy composites was investigated by using double cantilever beam (DCB) specimens. The dynamic interlaminar propagation toughness was obtained using a hybrid experimental-numerical method. Using a novel electromagnetic Hopkinson bar system, pure mode I fracture was guaranteed by symmetrical opening displacement rates in the range of 10 – 30 m/s. The crack velocities before crack arrest were between 100 and 250 m/s, which was monitored by crack-propagation gauges and high-speed photography. To model the interlaminar crack, a user-defined cohesive element was developed, which integrated the experimentally measured crack propagation history. The propagation toughness was calculated by the energy balance method and the dynamic J-integral technique. Results from extensive studies indicate that the dynamic propagation toughness is not a single-valued function of the crack velocity for mode I interlaminar crack. Both the external dynamic loads and the interaction with the bending waves emanating from the moving crack tip affect the behavior of the crack propagation.

Fatigue crack propagation under the condition where the superimposed stress history with different frequency components acts intermittently

ABSTRACT In this study, fatigue crack propagation under the condition where the superimposed stress history with different frequency components was given intermittently was investigated by numerical simulation and fatigue crack propagation test. The numerical simulation of fatigue crack propagation used in this study can consider the opening and closing behaviour of fatigue crack and implement stress history extraction algorithm that contributes to fatigue crack propagation under superimposed stress history with different frequency components. An advanced fracture mechanics approach based on the RPG (Re-tensile Plastic zone Generating) stress criterion to identify the effective stress intensity factor range was applied to estimate the fatigue crack propagation history. Fatigue crack propagation test under superimposed stress history containing different frequency component appearing intermittently was also conducted. Validity of our applied numerical simulation method was investigated by comparing numerical simulation results with experimental ones. As a result, the validity of our proposed numerical simulation procedure to estimate the fatigue crack propagation history under such a complicated applied stress history was confirmed.

Cosmic ray e± at high energy

There is a commonly expressed opinion in the literature, that cosmic-ray (CR) e+ come from a primary source, which could be dark matter or pulsars. In these proceedings we review some evidence to the contrary: namely, that e+ come from secondary production due to CR nuclei scattering on interstellar matter. We show that recent measurements of the total e± flux at E ≲ 3 TeV are in good agreement with the predicted flux of secondary e±, that would be obtained if radiative energy losses during CR propagation do not play an important role. If the agreement between data and secondary prediction is not accidental, then the requirement of negligible radiative energy losses implies a very short propagation time for high energy CRs: tesc ≲. 105 yr at rigidities R ≳ 3 TV. Such short propagation history may imply that a recent, near-by source dominates the CRs at these energies. We review independent evidence for a transition in CR propagation, based on the spectral hardening of primary and secondary nuclei around R ~ 100 GV. The transition rigidity of the nuclei matches the rigidity at which the e+ flux saturates its secondary upper bound.