Dispersal Dynamics Research Articles

Local resonance bandgap control in a particle-aligned magnetorheological metamaterial

Stimuli-responsive elastic metamaterials augment unique subwavelength features and wave manipulation capabilities with a degree of tunability, which enables them to cut across different time scales and frequency regimes. Here, we present an experimental framework for robust local resonance bandgap control enabled by enhanced magneto-mechanical coupling properties of a magnetorheological elastomer, serving as the resonating stiffness of a metamaterial cell. During the curing process, ferromagnetic particles in the elastomeric matrix are aligned under the effect of an external magnetic field. As a result, particle chains with preferred orientation form along the field direction. The resulting anisotropic behavior significantly boosts the sensitivity of the metamaterial’s elastic modulus to the imposed field during operation, which is then exploited to control the dispersive dynamics and experimentally shift the location and width of the resonance-based bandgap along the frequency axis. Finally, numerical simulations are used to project the performance of the magnetically-tunable metamaterial at stronger magnetic fields and increased levels of material anisotropy, as a blueprint for broader implementations of in situ tunable active metamaterials.

On the finite time blow-up for the high-order Camassa-Holm-Fokas-Olver-Rosenau-Qiao equations

In this paper, we are concerned with the finite time blow-up for the high-order Camassa-Holm-Fokas-Olver-Rosenau-Qiao equations, which is a generalization of the Camassa-Holm equation and the Fokas-Olver-Rosenau-Qiao equation. We explore how high-order nonlinearities affect the dispersive dynamics and breakdown mechanism of solutions. Firstly, we established the local well-posedness for the Cauchy problem in the framework of Besov spaces. Then, we derive the precise blow-up mechanism for strong solutions by means of the transport equation theory. Finally, a sufficient condition on initial data that leads to the finite time blow-up of the second-order derivative of the solutions is described in detail.

Complete genome reconstruction of the global and European regional dispersal history of the lumpy skin disease virus.

Lumpy skin disease virus (LSDV) has a complex epidemiology involving multiple strains, recombination, and vaccination. Its DNA genome provides limited genetic variation to trace outbreaks in space and time. Sequencing of LSDV whole genomes has also been patchy at global and regional scales. Here, we provide the first fine-grained whole genome sequence sampling of a constrained LSDV outbreak (southeastern Europe, 2015-2017), which we analyze along with global publicly available genomes. We formally evaluate the past occurrence of recombination events as well as the temporal signal that is required for calibrating molecular clock models and subsequently conduct a time-calibrated spatially explicit phylogeographic reconstruction. Our study further illustrates the importance of accounting for recombination events before reconstructing global and regional dynamics of DNA viruses. More LSDV whole genomes from endemic areas are needed to obtain a comprehensive understanding of global LSDV dispersal dynamics.

Potential Seed Dispersal by Persian Wild Ass in South Central Iran

Seed dispersal plays a pivotal role in plant ecology, impacting various aspects such as dispersal, reproduction, and population dynamics. In this study, we investigated the endozoochoric seed dispersal by the onager or Persian wild ass (Equus hemionus onager) in Qatrouiyeh National Park, located in south-central Iran. Fecal samples were collected from three plains within the park over three seed production seasons. A subsequent greenhouse experiment was conducted to identify and quantify the germinated seedlings. We discovered a total of 63 plant species across 45 genera and 21 families, with the majority of species categorized as annual or perennial forbs. Seasonal variations were observed for seedling count, species richness, and species diversity, with peak values observed during autumn. The seedlings consisted primarily of forbs (86%), followed by grasses (10%) and other plant types (4%). Astragalus podolobus, Lepidium vesicarium, and Chenopodium album emerged as the most abundant species from the fecal samples. Our findings shed light on the critical role played by the onager in the dispersal of numerous plant species and emphasized the potential cascading effects of herbivore-mediated seed dispersal. This highlights the significance of conserving and restoring the remaining populations of this threatened subspecies in arid habitats, where seed dispersal by abiotic factors is limited.

The Analytical Stochastic Solutions for the Stochastic Potential Yu–Toda–Sasa–Fukuyama Equation with Conformable Derivative Using Different Methods

We consider in this study the (3+1)-dimensional stochastic potential Yu–Toda–Sasa–Fukuyama with conformable derivative (SPYTSFE-CD) forced by white noise. For different kind of solutions of SPYTSFE-CD, including hyperbolic, rational, trigonometric and function, we use He’s semi-inverse and improved (G′/G)-expansion methods. Because it investigates solitons and nonlinear waves in dispersive media, plasma physics and fluid dynamics, the potential Yu–Toda–Sasa–Fukuyama theory may explain many intriguing scientific phenomena. We provide numerous 2D and 3D figures to address how the white noise destroys the pattern formation of the solutions and stabilizes the solutions of SPYTSFE-CD.

Differences in spore size and atmospheric survival shape stark contrasts in the dispersal dynamics of two closely related fungal pathogens

A frequently ignored but critical aspect of microbial dispersal is survival in the atmosphere. We exposed spores of two closely related, morphologically dissimilar, and economically important fungal pathogens to typical atmospheric environments and modeled their movement in the troposphere. Alternaria solani conidia are nearly 10 times larger than A. alternata conidia, but in our experiments, most died within 24 h, while over half of A. alternata conidia remained viable on day 12. Next, we modeled the movement of spores across North America. We predict 99% of the larger A. solani conidia settle within 24 h, with a maximum dispersal distance of 100 km. By contrast, most A. alternata conidia remain airborne for more than 12 days, and dispersal over long distances(2000 km) is likely. Counterintuitively, the larger A. solani conidia survive poorly, as compared to smaller A. alternata conidia, but also land sooner and move over shorter distances.

Observation and restriction of Aculops lycopersici dispersal in tomato layer cultivation

The tomato russet mite Aculops lycopersici has become a challenging pest in tomato production in the EU. The number of available acaricides is low, and the efficacy of biological control is limited. With this study, we aim to understand better the unhindered dispersal dynamics and develop a method to reduce dispersal on plants.To better understand the dynamics of A. lycopersici dispersal in layered tomato cultivation under practical conditions, a first trial was carried out. The trial confirmed that first A. lycopersici symptoms in practical cultivation usually occur in the lower or the middle third of tomato plants and then move upwards on plants. It was observed that plants, for a limited period of time often are able to grow new healthy leaves in the same pace as existing leaves, mostly in the lower and middle part of the plant are damaged by A. lycopersici. This is possible due to the fast growth rate of hybrid tomato varieties in layer cultivation. To test if the observed effect can be supported by further slowing down the upwards movement of the pest, a second trial was conducted. Here, the stems of inoculated tomato plants were blocked weekly for A. lycopersici by applying a ring of insect glue 15 cm below the tip of the plants. This stem blockage severely impaired the only active dispersal mode of A. lycopersici: walking. The growth of new plant material, when the method is applied, is able to exceed the speed with which A. lycopersici destroys plant material in layered tomato cultivation. This resulted in significantly less plant damage and prevented fruit damage on all treated plants. The approach of manipulating the plant stem and thereby restricting the movement of the mite on tomato plants could potentially be exploited for plant protection purposes under practical conditions.

Three-dimensional Numerical Simulations of a Liquid RP-2/O[formula omitted] based Rotating Detonation Engine

Rotating detonation engines (RDEs) offer increased thermal efficiencies and continuous thrust in a compact design. While non-premixed RDEs, where fuel and oxidizer are injected into the combustor through separate streams, have been extensively studied through experiments and numerical simulations, practical realizations of this technology mandate the use of the liquid fuels that power propulsion devices today. As a result, the strength and stability of the detonation wave are heavily influenced by not only the injection scheme but also the quality of the fuel mixture prepared for detonation. This mixture is a product of the dispersion and evaporation dynamics of liquid droplets in the presence of propagating detonation waves. To this end, the multiphase RDE system is investigated through high-fidelity simulations of a rocket-type RDE (RDRE) with liquid RP-2 fuel and gaseous oxygen. The Eulerian-Lagrangian compressible flow solver developed here provides detailed insight into the physical mechanisms important in a multiphase environment. A series of simulations are employed to understand both the droplet dynamics and mechanisms that lead to stable multiphase detonations and their resulting detonation structure. The interaction of the oxidizer injector, liquid droplets, and the detonation wave is discussed extensively. The injector dynamics lead to variations in droplet motion, where the injector recovery process enforces recirculation zones. Most importantly, the penetration of the injected droplets is crucial in their ability to evaporate; the lack thereof can quench detonation and result in a chaotic, deflagration-like mode. The injection scheme is crucial in the dispersion and evaporation of liquid droplets and the formation of detonable mixtures, perhaps more so than in gas-phase systems. The simulations provide detailed insight into the design of liquid-fueled RDE systems.

Culicoides-borne Orbivirus epidemiology in a changing climate.

Orbiviruses are of significant importance to the health of wildlife and domestic animals worldwide; the major orbiviruses transmitted by multiple biting midge (Culicoides) species include bluetongue virus, epizootic hemorrhagic disease virus, and African horse sickness virus. The viruses, insect vectors, and hosts are anticipated to be impacted by global climate change, altering established Orbivirus epidemiology. Changes in global climate have the potential to alter the vector competence and extrinsic incubation period of certain biting midge species, affect local and long-distance dispersal dynamics, lead to range expansion in the geographic distribution of vector species, and increase transmission period duration (earlier spring onset and later fall transmission). If transmission intensity is associated with weather anomalies such as droughts and wind speeds, there may be changes in the number of outbreaks and periods between outbreaks for some regions. Warmer temperatures and changing climates may impact the viral genome by facilitating reassortment and through the emergence of novel viral mutations. As the climate changes, Orbivirus epidemiology will be inextricably altered as has been seen with recent outbreaks of bluetongue, epizootic hemorrhagic disease, and African horse sickness outside of endemic areas, and requires interdisciplinary teams and approaches to assess and mitigate future outbreak threats.

The Effects of Varying Predator Dispersal Strength on Prey-Predator Dynamics with Refuge Process

The combined effects of (symmetric or asymmetric) dispersal and refuge mechanisms can have a significant impact on prey-predator dynamics. However, there remains a knowledge gap in concerning the incorporation of asymmetrical dispersal in the presence of prey refuges. Therefore, this paper aims to examine the influence of varying levels of asymmetrical (i.e., predator) dispersal on the interactions between prey and predators, as well as the role of prey refuges in facilitating species coexistence. The investigation begins by introducing an ordinary differential equation (ODE) model for the prey-predator system, which is subsequently extended to a partial differential equation (PDE) model. By conducting one-parameter bifurcation analysis on both models, the presence of transcritical and Hopf bifurcation points is established. Furthermore, the research delves into the spatio-temporal dynamics of the PDE model, capturing the intricate interactions between a specialized prey species and its predator. The focus is on examining the effects of different strengths of predator dispersal on the dynamics of the prey-predator system. The aim is to gain a comprehensive understanding of how predator dispersal influences the stability and persistence of the system, and to investigate the ecological implications of these dynamics in terms of prey-predator coexistence. Hence, the main findings of the research suggest that the increased levels of predator dispersal led to a wider range of prey refuges, supporting species coexistence. In conclusion, this study emphasises the critical importance of predator and prey dispersal dynamics in determining the key mechanisms that can promote species coexistence

Aberration compensation for enhanced holographic particle characterization.

Holographic particle characterization treats holographic microscopy of colloidal particles as an inverse problem whose solution yields the diameter, refractive index and three-dimensional position of each particle in the field of view, all with exquisite precision. This rich source of information on the composition and dynamics of colloidal dispersions has created new opportunities for fundamental research in soft-matter physics, statistical physics and physical chemistry, and has been adopted for product development, quality assurance and process control in industrial applications. Aberrations introduced by real-world imaging conditions, however, can degrade performance by causing systematic and correlated errors in the estimated parameters. We identify a previously overlooked source of spherical aberration as a significant source of these errors. Modeling aberration-induced distortions with an operator-based formalism identifies a spatially varying phase factor that approximately compensates for spherical aberration in recorded holograms. Measurements on model colloidal dispersions demonstrate that phase-only aberration compensation greatly improves the accuracy of holographic particle characterization without significantly affecting measurement speed for high-throughput applications.

Supercontinuum Generation in Dispersion Engineered Highly Doped Silica Glass Waveguides

AbstractThe effect of a lower index oxide layer inclusion within a highly doped silica glass slot waveguide is investigated for optimized supercontinuum generation at telecom wavelengths. By controlling the thickness of the oxide slot, it is demonstrated that one can engineer the waveguide dispersion profile in order to obtain supercontinua with vastly different spectral broadening dynamics and bandwidths. Using this approach, a waveguide with a low and flat dispersion profile of less than 43 across a wavelength range spanning over 1000 nm is designed and fabricated. It is shown that, when pumped at the telecom C‐band, a supercontinuum that spans over 1.5 octaves can be generated from 817 to 2183 nm. The numerical simulations, whose parameters are derived from the measured waveguide dimension and material indices, exhibit good agreement with experimental measurements, where one can observe both a qualitative and quantitative match in the supercontinuum overall spectrum and specific features (e.g., soliton and dispersive wave locations). This study represents an important step forward in the control and manipulation of dispersive and nonlinear dynamics in highly doped silica glass waveguides, paving the way toward advanced on‐chip broadband light manipulation.

Synanthropic flora near the medieval Castle Kolno, Stare Kolnie, SW Poland

The medieval Castle Kolno, situated near the village of Stare Kolnie, served as a custom house at the confluence of the rivers Budkowiczanka and Stobrawa. Numerous diaspores of plants were found in archaeological excavations, in the layers of the 14th-15th centuries AD. The excavations were located near the former access road, where increased human activity has affected the composition of the fossil macroremains of plants. Two Brassica species (cabbage B. oleracea and black mustard B. nigra) cultivated in small fields near the castle were recognised. Diaspores of weeds and ruderal plants were also deposited at the site. The most frequent were: Solanum nigrum, Setaria pumila, Chenopodium album, Rumex acetosella, Persicaria lapathifolia, and Urtica dioica. The collected set of fossil diaspores is composed of plant species associated with anthropogenic habitats and shows the dispersal dynamics in various micro-niches within them.

Dispersal, habitat filtering, and eco-evolutionary dynamics as drivers of local and global wetland viral biogeography.

Wetlands store 20-30% of the world's soil carbon, and identifying the microbial controls on these carbon reserves is essential to predicting feedbacks to climate change. Although viral infections likely play important roles in wetland ecosystem dynamics, we lack a basic understanding of wetland viral ecology. Here 63 viral size-fraction metagenomes (viromes) and paired total metagenomes were generated from three time points in 2021 at seven fresh- and saltwater wetlands in the California Bodega Marine Reserve. We recovered 12,826 viral population genomic sequences (vOTUs), only 4.4% of which were detected at the same field site two years prior, indicating a small degree of population stability or recurrence. Viral communities differed most significantly among the seven wetland sites and were also structured by habitat (plant community composition and salinity). Read mapping to a new version of our reference database, PIGEONv2.0 (515,763 vOTUs), revealed 196 vOTUs present over large geographic distances, often reflecting shared habitat characteristics. Wetland vOTU microdiversity was significantly lower locally than globally and lower within than between time points, indicating greater divergence with increasing spatiotemporal distance. Viruses tended to have broad predicted host ranges via CRISPR spacer linkages to metagenome-assembled genomes, and increased SNP frequencies in CRISPR-targeted major tail protein genes suggest potential viral eco-evolutionary dynamics in response to both immune targeting and changes in host cell receptors involved in viral attachment. Together, these results highlight the importance of dispersal, environmental selection, and eco-evolutionary dynamics as drivers of local and global wetland viral biogeography.

On the dispersion dynamics of liquid–liquid surfactant-laden flows in a SMX static mixer

This study aims to elucidate, for the first time, the intricate fundamental physics governing the dispersion dynamics of a surfactant-laden two-phase liquid–liquid system in the well-known SMX static mixer. Following the analysis carried out in the preceding publication to this work (Valdes et al., 2023), a comparative assessment of the most relevant and recurrent deformation and breakup mechanisms is conducted for a 3-drop scenario and then extrapolated to a more industrially-relevant multi-drop set-up. A parametric study on relevant surfactant physico-chemical parameters (i.e., elasticity, sorption kinetics) is undertaken, isolating each property by considering insoluble and soluble surfactants. In addition, the role of Marangoni stresses on the deformation and breakage dynamics is explored. High fidelity, three-dimensional direct numerical simulations coupled with a state-of-the-art hybrid interface capturing algorithm are carried out, providing a wealth of information previously inaccessible via volume-averaged or experimental approaches.

Directional-to-random transition of cell cluster migration

Efficient cell migration is crucial for the functioning of biological processes, e.g., morphogenesis, wound healing, and cancer metastasis. In this study, we monitor the migratory behavior of the 3D fibroblast clusters using live cell microscopy, and find that crowded environment affects cell migration, i.e., crowding leads to directional migration at the cluster’s periphery. The number of cell layers being stacked during seeding determines the directional-to-random transition. Intriguingly, the migratory behavior of cell clusters resembles the dispersion dynamics of clouds of passive particles, indicating that the biological process is driven by physical effects (e.g., entropy) rather than cell communication. Our findings highlight the role of intrinsic physical characteristics, such as crowding, in regulating biological behavior, and suggest new therapeutic approaches targeting at cancer metastasis.

Population structure and migration in Triatoma infestans (Hemiptera: Reduviidae) from the Argentine Chaco: An integration of genetic and morphometric data

Genetic and morphological structure of vector populations are useful to identify panmictic groups, reinfestation sources and minimal units for control interventions. Currently, no studies have integrated genetic and morphometric data in Triatoma infestans (Hemiptera: Reduviidae), one of the main vectors of Trypanosoma cruzi. We characterized the genetic and phenotypic structure of T. infestans at a small spatial scale (2–8 km), identified potential migrants and compared flight-related traits among genetic groups and between migrant and non-migrant insects in a well-defined area without insecticide spraying in the previous 12 years. We obtained microsatellite genotypes (N = 303), wing shape and size (N = 164) and body weight-to-length ratios (N = 188) in T. infestans from 11 houses in Pampa del Indio, Argentine Chaco. The uppermost level of genetic structuring partially agreed with the morphological groups, showing high degrees of substructuring. The genetic structure showed a clear spatial pattern around Route 3 and one genetic group overlapped with an area of persistent infestation and insecticide resistance. Females harboured more microsatellite alleles than males, which showed signs of isolation-by-distance. Wing shape discriminant analyses of genetic groups revealed low reclassification scores whereas wing size differed among genetic groups for both sexes. Potential migrants (8%) did not differ from non-migrants in sex, ecotope, wing shape and size. However, male migrants had lower W/L than non-migrants suggesting poorer nutritional state. Our findings may contribute to the understanding of population characteristics, dispersal dynamics and ongoing elimination efforts of T. infestans.

Gulf of Mexico larval dispersal: Combining concurrent sampling, behavioral, and hydrodynamic data to inform end-to-end modeling efforts through a Lagrangian dispersal model

We developed a Lagrangian larval dispersal model to estimate trajectories for eleven fish taxa inhabiting the Gulf of Mexico (GOM). Dispersal models are at family level resolution for Scaridae, Lutjanidae, Scombridae, Labridae, Ophichthidae, and Ophidiidae, at genus level resolution for Hemanthias, and at species level resolution for Trachurus lathami, Decapterus punctatus, Katsuwonus pelamis, and Euthynnus alleteratus. Hydrodynamics are provided by the West Florida Coastal Ocean Model (WFCOM). Larval samples are from the spring and fall SEAMAP ichthyoplankton surveys from 2007 to 2011. The Lagrangian model was run backwards/forwards in time from the sampling event to estimate spawning/settlement locations. Results were used to update larval dispersal dynamics in the GOM Atlantis ‘end-to-end’ ecosystem model for twelve functional groups. We compare dispersal and non-dispersal scenarios in the Gulf of Mexico Atlantis model and find differences in stock abundance and distribution of fish. This highlights that the abundance and distribution of fishery resources are sensitive to changing circulation patterns. This work takes an interdisciplinary approach to understanding larval dynamics and their impacts on ecosystems at the intersection of predictive statistical modeling, hydrodynamic modeling, and ecosystem modeling.

Within-field spatial patterns of Helicoverpa zea (Lepidoptera: Noctuidae) and spatial associations with stink bugs and their injury in field corn.

The corn earworm, Helicoverpa zea (Boddie) (Lepidoptera: Noctuidae), is a cosmopolitan pest in the field crop landscape in the southeastern United States. Field corn (Zea mays L.) is the most important midseason host for H. zea where intensive selection pressure occurs for resistance to insecticidal toxins from Bacillus thuringiensis (Bt). Because spatial patterns of H. zea in field corn have not been extensively studied, field corn was sampled for H. zea larvae and injury in 2021 and 2022. Patterns of spatial aggregation were identified in a number of fields in both larval populations and injury. Aggregation of H. zea larvae was less common at R5 than at R2. Associations between the spatial patterns of H. zea and the variability in crop phenology were identified in some fields, with positive associations between plant height and H. zea larvae, indicating that ovipositing H. zea moths avoid areas with reduced plant height and delayed reproductive maturity. Additionally, negative spatial associations between stink bug ear injury and H. zea larvae and their injury were found in a small number of cases, indicating some spatial interactions between the two pest complexes and their injury. Results from these studies provide valuable insight into the spatial patterns of H. zea in field corn. An understanding of the local dispersal and population dynamics of H. zea can be used to help further improve integrated pest management and insect resistance management programs for this major polyphagous pest.

Elevational range limits in naturalized Rumex conglomeratus likely formed by climate and lack of local adaptation

One of the fundamental questions in ecology is why species occur in some areas and not in others. Range limits, the boundaries between a species’ presence and absence, reflect the interplay of dispersal and population dynamics driven by biotic and abiotic conditions. As a result, range limits may shift as dispersal barriers are removed, climates change, and local species composition is altered, but the relative importance of these mechanisms is still not well understood. This is particularly true for introduced species, where current range limits may or may not reflect range limits at equilibrium, and is becoming more pressing under the effects of global climate change. To understand the drivers and stability of range limits in introduced Rumex conglomeratus, we used common garden experiments growing plants within, at the edge of and beyond their current range edge. Seeds were sourced from both lowland and upland populations and planted at all three sites. By measuring survival, growth, and the occurrence of reproduction, we tested whether upland populations are locally adapted to high elevation sites and whether plants were capable of surviving and reproducing above the current range edge. However, we found that upland populations were not better adapted to higher elevations, and often were small and performed more poorly than lowland populations across sites. Upland populations appear to be maintained by human-aided seed dispersal from lowland populations, which may constrain the opportunity for local adaptation. Although some plants survived above the current range edge, frost and growing season length restricted plant size and reproduction was infrequent. Therefore, the current range limit seems unlikely to expand as long as regular frost continues at the range edge and dispersal from the lowland continues to prevent local adaptation to upland environments.