Emergence Of Synchronization Research Articles

Outbreaks of Soil-Dwelling Diptera (Insecta): Has the Phenomenon a Natural or an Anthropogenic Origin

The data on the life-cycles of soil-dwelling Diptera which exhibit outbreaks are summarized. The main ecological parameters of the life-cycle of Diptera which may influence outbreaks are discussed: high fecundity of females, polyphagy of larvae, larval behavioral adaptations increasing their survival, tendency of adults toward synchronous emergence, and the ability of species to inhabit anthropogenic landscapes. It is shown that the potential ability of Diptera to exhibit outbreaks has natural mechanisms. Natural hazards like abrupt weather changes in the direction favorable for Diptera as well as anthropogenic influence may be additional factors provoking an outbreak.

Management of pigweed (Amaranthusspp.) in grain sorghum with integrated strategies

AbstractPigweed is difficult to manage in grain sorghum because of widespread herbicide resistance, a limited number of registered effective herbicides, and the synchronous emergence of pigweed with grain sorghum in Kansas. The combination of cultural and mechanical control tactics with an herbicide program are commonly recognized as best management strategies; however, limited information is available to adapt these strategies to dryland systems. Our objective for this research was to assess the influence of four components, including a winter wheat cover crop (CC), row-crop cultivation, three row widths, with and without a herbicide program, on pigweed control in a dryland system. Field trials were implemented during 2017 and 2018 at three locations for a total of 6 site-years. The herbicide program component resulted in excellent control (>97%) in all treatments at 3 and 8 weeks after planting (WAP). CC provided approximately 50% reductions in pigweed density and biomass for both timings in half of the site-years; however, mixed results were observed in the remaining site-years, ranging from no attributable difference to a 170% increase in weed density at 8 WAP in 1 site-year. Treatments including row-crop cultivation reduced pigweed biomass and density in most site-years 3 and 8 WAP. An herbicide program is required to achieve pigweed control and should be integrated with row-crop cultivation or narrow row widths to reduce the risk of herbicide resistance. Additional research is required to optimize the use of CC as an integrated pigweed management strategy in dryland grain sorghum.

Impact of Biotic and Abiotic Stressors on Managed and Feral Bees.

Large-scale declines in bee abundance and species richness over the last decade have sounded an alarm, given the crucial pollination services that bees provide. Population dips have specifically been noted for both managed and feral bee species. The simultaneous increased cultivation of bee-dependent agricultural crops has given rise to additional concern. As a result, there has been a surge in scientific research investigating the potential stressors impacting bees. A group of environmental and anthropogenic stressors negatively impacting bees has been isolated. Habitat destruction has diminished the availability of bee floral resources and nest habitats, while massive monoculture plantings have limited bee access to a variety of pollens and nectars. The rapid spread and increased resistance buildup of various bee parasites, pathogens, and pests to current control methods are implicated in deteriorating bee health. Similarly, many pesticides that are widely applied on agricultural crops and within beehives are toxic to bees. The global distribution of honey bee colonies (including queens with attendant bees) and bumble bee colonies from crop to crop for pollination events has been linked with increased pathogen stress and increased competition with native bee species for limited resources. Climatic alterations have disrupted synchronous bee emergence with flower blooming and reduced the availability of diverse floral resources, leading to bee physiological adaptations. Interactions amongst multiple stressors have created colossal maladies hitting bees at one time, and in some cases delivering additive impacts. Initiatives including the development of wild flower plantings and assessment of pesticide toxicity to bees have been undertaken in efforts to ameliorate current bee declines. In this review, recent findings regarding the impact of these stressors on bees and strategies for mitigating them are discussed.

Quantum synchronization in a collision model

We reveal the emergence of environment-induced spontaneous synchronization between two spin-1/2 quantum objects in a collision model setting. In particular, we determine the conditions for the dynamical establishment of synchronous evolution between local spin observables of a pair of spins undergoing open-system dynamics in the absence of an external drive. Exploiting the versatility of the collision model framework, we show that the formation of quantum or classical correlations between the principal spin pair are of no significant relevance to the manifestation of spontaneous quantum synchronization between them. Furthermore, we discuss the consequences of thermal effects on the environmental spins for the emergence of quantum synchronization.

Collective synchronization of the multi-component Gross–Pitaevskii–Lohe system

Abstract In this paper, we propose a multi-component Gross–Pitaevskii–Lohe (GPL for brevity) system in which quantum units interact with each other such that collective behaviors can emerge asymptotically. We introduce several sufficient frameworks leading to complete and practical synchronizations in terms of system parameters and initial data. For the modeling of interaction matrices we classify them into three types (fully identical, weakly identical and heterogeneous) and present emergent behaviors correspond to each interaction matrix. More precisely, for the fully identical case in which all components are same, we expect the emergence of the complete synchronization with exponential convergence rate. On the other hand for the remaining two interaction matrices, we can only show that the practical synchronization occurs under well-prepared initial frameworks. For instance, we assume that a coupling strength is sufficiently large and perturbation of an interaction matrix is sufficiently small. Regarding the practical synchronization estimates, due to the possible blow-up of a solution at infinity, we a priori assume that the L 4 -norm of a solution is bounded on any finite time interval. In our analytical estimates, two-point correlation function approach will play a key role to derive synchronization estimates. We also provide several numerical simulations using time splitting Crank–Nicolson spectral method and compare them with our analytical results.

Analysis of tropical and temperate elevational gradients in arthropod abundance

Arthropods are a major component of ecosystems, in terms of both their biomass and the variety of functional roles they play. Yet we lack a clear understanding of how arthropod abundance changes along environmental gradients. We compiled published literature on overall arthropod abundances (number of individuals) along elevational gradients and performed a formal meta-analysis on the role of latitude, climatic variables, and interactions with ants in shaping the pattern. Specifically, we asked if patterns of arthropod abundance along different elevational gradients are associated with gradients of seasonality and precipitation and whether ant abundance affects other arthropods. Arthropod abundance peaks at higher elevations at mid-latitudes than low latitudes; hence, the correlation between arthropod abundance and elevation shifts from negative to positive with an increase in latitude. We suggest these patterns reflect a steep elevational gradient in the length of growing season at mid-latitudes, with the short growing season at high elevations in mid-latitudes leading to synchronous emergence and reproduction of arthropods generating a sharp increase in abundance. Precipitation and ant abundance do not have a consistent effect on arthropod abundance along most elevational gradients. However, on gradients with a very dry base and sharp increase in precipitation with elevation, arthropod abundance peaks at higher elevations. Overall, our results suggest that future changes in the length of growing season will impact the elevation at which summer arthropod abundance peaks and the sharpness of the peak, likely affecting diversity and distribution of other taxa that interact with arthropods.

Phase transition to synchronization in generalized Kuramoto model with low-pass filter.

A second-order continuous synchronization has been well documented for the classic Kuramoto model. Here we generalize the classic Kuramoto model by incorporating a low-pass filter (LPF) in the coupling, which serves as a simple form of indirect coupling through a common external dynamic environment. We uncover that a first-order explosive synchronization turns out to be a very generic phenomenon in this generalized Kuramoto model with LPF. We establish theoretical results by providing a rigorous analytical treatment, which is validated by conducting extensive numerical simulations. Our study provides a new root for the emergence of first-order explosive synchronization, which could substantially deepen the understanding of the underlying mechanism of a first-order phase transition towards synchronization in coupled dynamical networks.

Explosive phenomena in complex networks

The emergence of large-scale connectivity and synchronization are crucial to the structure, function and failure of many complex socio-technical networks. Thus, there is great interest in analyzing phase transitions to large-scale connectivity and to global synchronization, including how to enhance or delay the onset. These phenomena are traditionally studied as second-order phase transitions where, at the critical threshold, the order parameter increases rapidly but continuously. In 2009, an extremely abrupt transition was found for a network growth process where links compete for addition in attempt to delay percolation. This observation of "explosive percolation" was ultimately revealed to be a continuous transition in the thermodynamic limit, yet with very atypical finite-size scaling, and it started a surge of work on explosive phenomena and their consequences. Many related models are now shown to yield discontinuous percolation transitions and even hybrid transitions. Explosive percolation enables many other features such as multiple giant components, modular structures, discrete scale invariance and non-self-averaging, relating to properties found in many real phenomena such as explosive epidemics, electric breakdowns and the emergence of molecular life. Models of explosive synchronization provide an analytic framework for the dynamics of abrupt transitions and reveal the interplay between the distribution in natural frequencies and the network structure, with applications ranging from epileptic seizures to waking from anesthesia. Here we review the vast literature on explosive phenomena and synthesize the fundamental connections between models and survey the application areas. We attempt to classify explosive phenomena based on underlying mechanisms and to provide a coherent overview and perspective for future research to address the many vital questions that remained unanswered.

Synchronization to extreme events in moving agents

Interactions amongst agents frequently exist only at particular moments in time, depending on their closeness in space and movement parameters. Here we propose a minimal model of moving agents where the network of contacts changes over time due to their motion. In particular, agents interact based on their proximity in a two-dimensional space, but only if they belong to the same fixed interaction zones. Our research reveals the emergence of global synchronization if all the interaction zones are attractive. However, if some of the interaction zones are repulsive, they deflect synchrony and lead to short-lasting but recurrent deviations that constitute extreme events in the network. We use two paradigmatic oscillators for the description of the agent dynamics to demonstrate our findings numerically, and we also provide an analytical formulation to describe the emergence of complete synchrony and the thresholds that distinguish extreme events from other intermittent states based on the peak-over-threshold approach.

Evolutionary Hysteresis and Ratchets in the Evolution of Periodical Cicadas.

It has been previously hypothesized that the perfectly synchronized mass emergence of periodical cicadas (Magicicada spp.) evolved as a result of a switch from size-based to age-based emergence. In the former case, cicada nymphs emerge immediately (at the first opportunity) on reaching maturity, whereas in the latter case, nymphs wait in order to emerge at a specific age. Here we use an individual-based model to simulate the cicada life cycle and to study the evolution of periodicity. We find that if age-based emergence evolves in a constant abiotic environment, it typically results in a population that is protoperiodic, and synchronous emergence of the whole population is not achieved. However, perfect periodicity and synchronous emergence can be attained, if the abiotic environment changes back and forth between favorable and unfavorable conditions (hysteresis). Furthermore, once age-based emergence evolves, generally it can only be invaded by other age-based emergence strategies with longer cycle lengths (evolutionary ratchet). Together, these mechanisms promote the evolution of long periodic life cycles and synchronous emergence in the Magicicada. We discuss how our results connect to previous theories and recent phylogenetic studies on Magicicada evolution.

The emergence of synchrony in networks of mutually inferring neurons

This paper considers the emergence of a generalised synchrony in ensembles of coupled self-organising systems, such as neurons. We start from the premise that any self-organising system complies with the free energy principle, in virtue of placing an upper bound on its entropy. Crucially, the free energy principle allows one to interpret biological systems as inferring the state of their environment or external milieu. An emergent property of this inference is synchronisation among an ensemble of systems that infer each other. Here, we investigate the implications of neuronal dynamics by simulating neuronal networks, where each neuron minimises its free energy. We cast the ensuing ensemble dynamics in terms of inference and show that cardinal behaviours of neuronal networks – both in vivo and in vitro – can be explained by this framework. In particular, we test the hypotheses that (i) generalised synchrony is an emergent property of free energy minimisation; thereby explaining synchronisation in the resting brain: (ii) desynchronisation is induced by exogenous input; thereby explaining event-related desynchronisation and (iii) structure learning emerges in response to causal structure in exogenous input; thereby explaining functional segregation in real neuronal systems.

The role of coupling factors on the emergence of synchronization and chimera patterns in network of non-locally coupled pancreatic β-cells

The study of the pancreatic β-cells and their collective behavior is of great importance from the fluctuating insulin perspective. In this paper, a network of non-locally coupled β-cells is considered. It has been frequently reported that bursting of β-cells and their synchronous oscillations are associated with gap junctions. Therefore, a linear coupling between the membrane potentials of the clustered cells is used to model the gap junctions. The effects of coupling strength and number of neighbouring connections on the behavior of the cells is also investigated. Various collective patterns including chimera state, cluster synchronization and complete synchronization are observed. It is attained that the dynamic of the cells, e.g., being chaotic or periodic, has a significant role in their behavior. The observed collective behaviors not only is related to the network's parameters, but also heavily depends on its underlying topology. Detailed analytical description and extensive numerical simulations are provided to support the claims.

Asymmetric interactions and their consequences for vital rates and dynamics: the smaller tea tortrix as a model system

Asymmetric interactions among conspecifics can have diverse effects on population dynamics including stabilization, generation of cycles, and induction of chaotic fluctuations. A difficult challenge, however, is establishing the link between the impact of asymmetric interactions on life history and the consequences for population dynamics. The smaller tea tortrix, Adoxophyes honmai, is a good example. Larval instars differ dramatically in size and have a tendency for cannibalism, which suggests the potential for strong asymmetric interactions among instars. Yet whether these asymmetries have any role in generating the distinct single-generation cycles observed in the field and laboratory is unclear. Here we report on the development of a new experimental approach to characterize the impact of asymmetric interactions on life history that can be directly embedded into stage-structured population models. The experiments use donor-replacement protocols in which focal individuals are challenged to complete their life cycles in competitive environments where the instar and density of the competitors are held constant. The experimentally derived interaction surface contains all the information about stage-specific interactions and provides a straightforward framework for evaluating alternative ways of abstracting the interactions into traditional models of asymmetric competition. Working with the smaller tea tortrix, we found strong evidence of asymmetric interactions and identified critical "tipping points" in the competitive environment that strongly affected survival but not development. We incorporated the experimentally derived interaction surface into a stage-structured population model and found that despite the strong impact that asymmetric interactions have on tea tortrix life history, they do not scale-up to impact the predicted asymptotic population dynamics. Comparing these dynamics with two abstracted models of stage-structured interactions revealed that while the quantitative details of the emergent dynamics depends on the shape of the interaction surface, the qualitative features, such as the emergence of single-generation cycles and rapid synchronization of development among individuals, are pleasingly robust.

Synchronization of nonuniform Kuramoto oscillators for power grids with general connectivity and dampings

We consider the synchronization problem of swing equations, a second-order nonuniform Kuramoto model, with general connectivity and dampings. This is motivated by its relevance to the dynamics of power grids. As an important topic in power grids, people have been paying special attention to the transient stability which concerns the system’s ability to reach an acceptable synchronism after a transient disturbance. For this concern, an important problem is to determine whether the post-fault state is located in the basin of attraction of synchronous states (sync basin). Recently this issue is becoming more and more challenging since the highly stochastic renewable power sources exert more transient disturbances on the power grids with increasing size and complexity. In Dörfler et al (2013 Proc. Natl Acad. Sci. USA 110 2005–10), it was pointed out that the sync basin is an important unsolved problem. In Li et al (2014 SIAM J. Control Optim. 52 2482–511), an explicit estimate on the region of attraction of coupled oscillators with homogenous damping for network with diameter less than two was obtained. However, it turns out that these assumptions are too restrictive in many real situations. The purpose of this work is to study the emergence of synchronization and give an estimate for sync basin for the nonuniform Kurmaoto model on connected graphs with general dampings, which is the most general setting for a connected power grid. Our strategy is based on the gradient-like formulation and energy estimate.

Emergence of synchronization in multiplex networks of mobile Rössler oscillators.

Different aspects of synchronization emerging in networks of coupled oscillators have been examined prominently in the last decades. Nevertheless, little attention has been paid on the emergence of this imperative collective phenomenon in networks displaying temporal changes in the connectivity patterns. However, there are numerous practical examples where interactions are present only at certain points of time owing to physical proximity. In this work, we concentrate on exploring the emergence of interlayer and intralayer synchronization states in a multiplex dynamical network comprising of layers having mobile nodes performing two-dimensional lattice random walk. We thoroughly illustrate the impacts of the network parameters, in particular, the vision range ϕ and the step size u together with the inter- and intralayer coupling strengths ε and k on these synchronous states arising in coupled Rössler systems. The presented numerical results are very well validated by analytically derived necessary conditions for the emergence and stability of the synchronous states. Furthermore, the robustness of the states of synchrony is studied under both structural and dynamical perturbations. We find interesting results on interlayer synchronization for a continuous removal of the interlayer links as well as for progressively created static nodes. We demonstrate that the mobility parameters responsible for intralayer movement of the nodes can retrieve interlayer synchrony under such structural perturbations. For further analysis of survivability of interlayer synchrony against dynamical perturbations, we proceed through the investigation of single-node basin stability, where again the intralayer mobility properties have noticeable impacts. We also discuss the scenarios related mainly to effects of the mobility parameters in cases of varying lattice size and percolation of the whole network.

Synchronization Cost of Coupled Oscillators With a Spatial Embedding

Synchronous behavior brings advantages for complex systems. Yet, this advantage comes with a cost: Emergence and sustainability of synchronization requires a continuous exchange among the interacting units. Thus, networks with optimal synchronization dynamics is a subject of active research. In this study, we define a cost function for synchronization which takes into account both the network structure which is embedded in space and the dynamic coupling within the system. Beginning from a fully connected network and using an edge pruning strategy based on simulated annealing, we searched for optimal configurations for synchronization with minimum cost. We observed that the same levels of synchronization with a fully connected network can be reached by different networks with sparse connections. We conclude that the chain structure, clustering behavior and degree-frequency relations are the main determinants of optimally synchronizable network structures.

Biotremology: The Sound of One Egg Cracking

In many animals, eggs within a clutch emerge more or less at the same time. A new study identifies vibrations of eggs cracking open as the cue that triggers synchronous emergence in an insect.

Complete synchronization of chaotic maps under advection

We explore the emergence of complete synchronization under advection in a linear array of chaotic maps. The couplings decay algebraically with the distance between maps, covering from nearest-neighbor to infinite-range interactions, while the update protocol allows us to scan continuously from nondelayed to one-time-delayed dynamics. When the couplings are symmetric (diffusive) and the update is nondelayed, it is well known that chaotic orbits can synchronize if the range of interactions is long enough, while the inclusion of delays allows complete synchronization of a variety of other trajectories besides chaotic ones. Now we investigate through numerical simulations and theoretical analysis how the inclusion of antisymmetric couplings (advection) affects this scenario, showing the interplay among advection, the range of the interactions, and delay. In general, advection reduces the region in parameter space where completely synchronized states are stable, without affecting the nature of the orbits. The presence of delay can lessen the destabilizing effect of advection, such that synchronization is still possible even when couplings are short-range, for a suitable contribution of the delay, but globally coupled lattices are also affected when delayed responses predominate.

Unveiling noiseless clusters in complex quantum networks

The transport and storage of quantum information, excitations, and entanglement, within and across complex quantum networks is crucially affected by the presence of noise induced by their surroundings. Generally, the interaction with the environment deteriorates quantum properties initially present, thus limiting the efficiency of any quantum-enhanced protocol or phenomenon. This is of key relevance, for example, in the design of quantum communication networks and for understanding and controlling quantum harvesting on complex systems. Here, we show that complex quantum networks, such as random and small-world ones, can admit noiseless clusters for collective dissipation. We characterize these noiseless structures in connection to their topology addressing their abundance, extension, and configuration, as well as their robustness to noise and experimental imperfections. We show that the network degree variance controls the probability to find noiseless modes and that these are mostly spanning an even number of nodes, like breathers. For imperfections across the network, a family of quasi-noiseless modes is also identified shielded by noise up to times decreasing linearly with frequency inhomogeneities. Large noiseless components are shown to be more resilient to the presence of detuning than to differences in their coupling strengths. Finally, we investigate the emergence of both stationary and transient quantum synchronization showing that this is a rather resilient phenomenon in these networks.

Status, distribution, and nesting ecology of Snapping Turtle (<i>Chelydra serpentina</i>) on Cape Breton Island, Nova Scotia, Canada

Based on current knowledge of the ecology and distribution of Snapping Turtle (Chelydra serpentina), both in eastern Canada and elsewhere, we conclude this species is native to Cape Breton Island. Seventy-two reports of Snapping Turtle from Cape Breton (1999–2017) indicate a range centred in the area south of Bras d’Or Lake. Date of oviposition ranged from 19 June to 10 July (median = 26 June) among 26 nests observed during 2012–2014. Clutch size for these nests was 23–65 eggs (mean = 46) and among 25 protected nests average rate of hatchling emergence was 21.5%. Time from oviposition to emergence of hatchlings (n = 256) was 75–120 days (mean = 87.2; SD = 9.0) among 20 nests. First emergence ranged from 9 September to 20 October (75–114 nest days; mean = 90) and last emergence ranged from 13 September to 28 October (86–120 nest days; mean = 100). Duration of emergence ranged from one day (i.e., synchronous emergence; five nests) to 37 days (mean = 11 days). The number of days on which hatchlings emerged at a nest ranged from one to nine days (mean = 4 days). Maximum carapace length was 25.0–31.8 mm (mean = 29.0 mm) and maximum carapace width was 23.5–30.0 mm (mean = 27.0 mm) for 256 hatchlings that emerged from 20 protected nests. Mass of hatchlings was 4.9–9.9 g (mean = 7.8 g).