Competitive Coexistence Research Articles

Copepod cryptic species as aquatic invaders

Abstract. The dispersal of aquatic organisms has especially increased since the 19th century, mainly due to the introduction of metal ships with ballast compartments or with birds. Along with easily visible aquatic organisms, there are invasions of less noticeable aquatic organisms, like copepods, which can mainly be recognized by experts. A special group is made up of cryptic species for which morphological identification is inaccessible or very difficult. This review is devoted to the identification, description and analysis of the dispersal routes of three copepod cryptic species complexes into waterbodies. Using molecular-genetic methods, Eurytemora carolleeae introduction were revealed in 2007. After describing this invader as a new species, its distribution was also studied using morphology. The invasions of Acanthocyclops americanus and Eurytemora caspica were mainly studied using morphological methods since the species have already been described; however, molecular-genetic methods were also used to confirm their distinctions from local forms. The real distribution of the former cosmopolitan species Eucyclops serrulatus was studied using a multidisciplinary approach that combined molecular-genetic, cross-hybridization and morphological methods. Judging by the distribution of local E. serrulatus sensu stricto populations in coastal waterbodies of most continents, this species can apparently serve as a good marker of the species dispersal processes with ships. The three possible scenarios resulting from cryptic species introductions and their interaction with local fauna were competitive displacement (A. americanus), competitive coexistence (E. carrolleeae) and independent development without competition (E. serrulatus). The role of cryptic species invasion in aquatic biodiversity modification is discussed.

B2C online ride-hailing pricing and service optimization under competitions

<p style='text-indent:20px;'>B2C online ride-hailing is to provide customers with anytime, anywhere and on-call ride services by professional vehicles and professional drivers. How to maintain good service quality and reasonable pricing under competition is of importance to a platform. In this paper, we will integrate pricing and service together to maximize the profit of a platform through Nash game theory. Specifically, we will establish the models for there scenarios: the demand market competition under decline of ride demand, the supply market competition under surge of ride demand, and the coexistence of demand and supply market competition for stable ride demand. Then, the Nash equilibriums are derived for the three models which are corresponding to minimize ride price, optimize quality of efforts and maximize profit. Our results uncover that the driver's incentive amount is conducive to the profit of both platform and the drivers for the case of demand market competition. The platforms and drivers achieve the highest profit under supply market competition, and the strategy through minimizing price and maximizing service can effectively adjust the balance between market supply and demand.</p>

Эволюция империи: от Древнего мира к Новому времени

Imperial formations occupy a key place in the political and religious history of Humankind. The article traces the evolution of this phenomenon, with a future global perspective, from the time of the emergence of macrostates in the Ancient World, through the period of the classical empires of Antiquity to the religious empires of the Middle Ages and the late empires of the New Age, in the space of Asia Minor and the Greater Mediterranean. The focus is on the transformation of the ideological foundations of imperial formations, traced primarily on the basis of titular formulas, which are the most important source on the history of the ideological self-identification of states. The analysis revealed several evolutionary phases of imperial construction, characterized by the following features: 1) “mechanical” consolidation of primary polys-nomic political formations around a particular military-administrative center, with the preservation of mosaicism and polycentrism in the religious sphere; 2) formation of the new generation of all-imperial religious systems (usually associated with the ruler’s cult), designed to complement military and political consolidation by an ideological one; 3) displacement of primary personality-oriented imperial cults by more morally authoritative universal religions with a transcendental ideal (Christianity, Islam); 4) secondary politicization of theocratic empires, leading to the consolidation of religious-state dualism (emperor / patriarch; caliph / sultan); 5) final decline of politicized theocracies and their more or less painful transformation into national states of the modern type, formed in the specific conditions of Western Europe. The phenomenon of instability of monopolar geopolitical structures and, on the contrary, the impressive stability of bipolar configurations, embodied in the evolutionary space of the Greater Mediterranean in the competitive coexistence of Hellenism and the East, Rome and Iran, Byzantium and the Caliphate, the Russian and Ottoman empires, was identified.

Competitive exclusion and coexistence in an intraguild predation model with Beddington–DeAngelis functional response

Competitive exclusion is a phenomenon that often occurs in ecology when two species compete for the same limited resource, while coexistence of predator and prey is required to sustain a predator–prey system. It is of great interest to examine if coexistence of intraguild predator and prey is possible when they are competing for the same resource. In this paper, we study competitive exclusion and coexistence in an intraguild predation model that incorporates species’ mutual interference characterized by a Beddington–DeAngelis functional response. We derive conditions for competitive exclusion and conditions for coexistence of intraguild predator and prey. This is achieved by discussing the existence, local and global stability of all feasible equilibria and uniform persistence. Numerical simulations are carried out to explore effects of intraguild predator interference and intraguild predation strength on the coexistence modes of intraguild predator and prey.

Dynamic properties for a stochastic food chain model

In this paper, Lyapunov exponents of ergodic invariant measures are used to study dynamic properties for a stochastic food chain model, which consists of two competing predators and one prey. Ayala’s experimental result, or rather, competitive coexistence is showed to be possible in this random case. Furthermore, the considered stochastic model have five points of dynamical bifurcation, which happen to be the thresholds (between survival and extinction) of the system or each species. In addition, the necessity of introducing environmental noise is verified by the fact that environmental driving force can drive the system towards extinction from partial extinction or coexistence. Moreover, all the theoretical results are well verified by numerical simulations. It is worth mentioning that we make a first attempt at using meshing method and statistical data to test Lyapunov exponents for two-dimensional boundary measures, and this is an innovation in the numerical methods.

Plant-Pollinator Specialization: Origin and Measurement of Curvature.

AbstractA feature of biodiversity is the abundance of curves displayed by organs and organisms. Curvature is a widespread, convergent trait that has important ecological and evolutionary implications. In pollination ecology, the curvature of flowers and pollinator mouthparts (e.g., hummingbird bills) along the dorsiventral plane has been associated with specialization, competition, and species coexistence. Six differing methods have historically been used to measure curvature in pollination systems; we provide a solution to this inconsistency by defining curvature using well-established concepts from differential geometry. Intuitively, curvature is the degree to which a line is not straight, but more formally it is the rate at which the tangent of a curve changes direction with respect to arc length. Here, we establish a protocol wherein a line is fitted against landmarks placed on an image of a curved organ or organism, then curvature is computed at many points along the fitted line and the sum taken. The protocol is demonstrated by studying the development of nectar spur curvature in the flowering plant genus Epimedium (Berberidaceae). By clarifying the definition of curvature, our aim is to make the language of comparative morphology more precise and broadly applicable to capture other curved structures in nature.

Camera trap reveals the co-occurrence patterns of two sympatric muntjac species in southern Anhui Province, China: No spatial segregation.

The competitive relationship and coexistence pattern among close related species have long been one of the hot issues in ecological research. Interspecies interactions can exert important influences on the local distribution of rare species. Black muntjac Muntiacus crinifrons is an endemic species to eastern China, currently restricted to limited regions. In contrast, Chinese muntjac Muntiacus reevesi is the most common and widespread deer in southern China. Both species co‐occur in southern Anhui and western Zhejiang Province. Little is known about the interaction of these two sympatric‐related species. In this study, to investigate the site use determinants and co‐occurrence pattern of the two sympatric muntjac species, we conducted a camera trap survey across about 250 km2 in mountainous area of southern Anhui Province, China. We adopted a multistep approach to incorporate habitat preferences while modeling occupancy and detection. We found that the two species did not separate along elevation gradient (range from 400 m to 1,400 m) as described in previous studies. Results of single‐species occupancy models indicated that elevation had positive effects on the site use of both species, while slope had an opposite influence on their site use. Positive effects of elevation on the site use implied that both species try to avoid human interference at low elevations. Significant negative effect of slope on the site use of black muntjac suggested that the species prefer habitat with gentle slope and avoided steep. Co‐occurrence models and species interaction factors provided evidence that the two muntjac species had an independent occupancy (ψ BM CM = ψ BM cm, SIF = 1) and exhibited a positive species interaction in detection probability (p BM < r BM CM). Combined with the results of previous studies, we suggested that it was fine differentiation in microhabitats and food resources utilization rather spatial or temporal segregation that allowed the two species co‐occurrence. The site use determinants revealed in our study would be useful for the habitat conservation and restoration for the rare black muntjac, and the co‐occurrence pattern of the two sympatric muntjac species could provide useful information for deep understanding of the coexistence mechanism among forest‐dwelling ungulates.

Dynamical behavior of a Lotka–Volterra competition system in open advective environments

In this paper, we are concerned with a general reaction–diffusion–advection model which characterizes the interactions between two competing species in river environments. By regarding advection rates of two species as variable parameters, we provide an efficient way to completely understand the local dynamics. It turns out that there always exist two critical curves which may separate competition outcomes into competitive exclusion, bistability, and coexistence. As a further development, under the assumption that the ratio of advection and diffusion rates of one species is greater than or equal to that of the other species, we give a specific classification on the global dynamics, which shows that bistability does not happen, but coexistence and competitive exclusion may occur. These interesting results indicate that advective movements play a key role in determining the dynamical behaviors.

Межгосударственный трансфер технологий по мирному использованию атома в 1950-1960-е гг. (на материалах Физико-химического института им. Л. Я. Карпова)

The aim of the study is to determine the ways, methods and directions of interstate technology transfer in the field of research on the peaceful use of atomic energy in the USSR in the 1950-1960s. The article considers the process of scientists’ interstate interaction in the field of the peaceful use of the atom on the basis of documents of the Union Leading Research Institute of Physics and Chemistry named after L. Ya. Karpov subordinate to the USSR Ministry of Chemical Industry. The scientific originality of the research consists in an integrated approach to the analysis of the interaction of political, scientific-organizational, production-technological, social, economic factors that determined technological transfer in the conditions of “competitive coexistence” of the USSR with the western (capitalist) world in the 1950-1960s. As a result of the research, the ways and practical results of the interstate transfer of technologies in the field of research and development on the peaceful use of atomic energy in the USSR in the 1950-1960s have been identified.

The Less Selfish Gene

Abstract Why have millions of readers and viewers become magnetized by the hitherto arcane field of plant communication? The article argues that the contemporary appeal of plant communication is rooted in a quest for alternative modes of being to neoliberalism, modes more accommodating of the coexistence of cooperation and competition in human and more-than-human communities. This ascendant understanding of plant communication and forest dynamics offers a counternarrative of flourishing, a model of what George Monbiot has called, in another context, “private sufficiency and public wealth.”

Innovation and Performance of Manufacturing Firms in Aspirant Markets: An Institutional Environment Approach

The recent years have witnessed an increasing number of manufacturers in developed markets pursuing service-led innovation to secure their sustainable growth and competitive positions. This study compares the manufacturing firm performance outcomes of two types of innovation activities in the value chain (i.e., service innovation and product innovativeness) contingent on institutional environment but in an aspirant market – China. To do so we conducted two studies: A secondary data study (Study 1) used a longitudinal panel dataset of 1,167 manufacturing firms and a robustness study (Study 2) used primary survey data from 171 manufacturing firms. Both studies offer consistent empirical results that in the dysfunctional competition environment, and in contrast to product innovativeness, service innovation is less effective for manufacturing performance but works more effectively for performance in the complicated institutional environment when government support and dysfunctional competition co-exist. The research contributes to the fields of aspirant markets and innovation by developing our understanding of the firm’s strategic responses pertaining to innovation in the context of a complicated institutional environment, the latter informed by structuration theory. The paper offers a fine-grained view to manufacturing innovation and provides the practical implications for managers and clear guidance to firms and governments in the aspirant markets in regards to innovation practice, strategy, and policy.

Competitive coexistence of seasonal breeders.

Many species are annual breeders who, between reproductive events, consume resources and may die. Their resource often reproduces continuously or has short, overlapping generations. An accurate model for such life cycles needs to represent both, the discrete- and the continuous-time processes in the community. The dynamics of a single discrete breeder and its resource can differ significantly from that of a fully continuous consumer-resource community (e.g., Lotka-Volterra) and that of a fully discrete one (e.g., Nicholson-Bailey). We study the dynamics of multiple discrete breeders on a single resource and identify a number of coexistence mechanisms and complex dynamics. The resource grows logistically, resource consumption is linear and consumer reproduction can be linear or nonlinear. We derive explicit conditions for the positive equilibrium state to exist and for mutual invasion to occur at that equilibrium. Stable equilibrium coexistence of more than one consumer is possible only when reproduction is nonlinear. Higher resource growth rate generally allows more consumers to stably coexist. Our explicit formulas allow us to generate communities of many coexisting consumers. Total biomass in the system seems to increase with the number of coexisting consumers. Complex patterns of coexistence arise, including bistability of equilibrium and non-equilibrium coexistence. The mixed continuous-discrete modeling approach can easily be adapted to study how certain aspects of global change affect discrete breeder communities.

An Improved Lotka–Volterra Model Using Quantum Game Theory

Human decision-making does not conform to the independent decision-making hypothesis from classical decision-making theory. Thus, we introduce quantum decision-making theory into the Lotka–Volterra model (L–V model), to investigate player population dynamics while incorporating the initial strategy, game payoffs and interactive strategies in an open social system. Simulation results show that: (1) initial strategy, entanglement intensity of strategy interaction, and payoffs impact population dynamics; (2) In cooperative coexistence, game players mutually exceed the initial environmental capacity in an open system, but not in competitive coexistence; (3) In competitive coexistence, an initial strategy containing an entanglement intensity of strategies plays a vital role in game outcomes. Furthermore, our proposed model more realistically delineates the characteristics of population dynamics in competitive or cooperative coexistence scenarios.

Gammarus (Amphipoda) species competitive exclusion or coexistence as a result of climate change in the Arctic?

Gammarus (Amphipoda) species competitive exclusion or coexistence as a result of climate change in the Arctic?

Segregation competition and complexion coexistence within a polycrystalline grain boundary network

Interfacial segregation can stabilize grain structures and even lead to grain boundary complexion transitions. However, understanding of the complexity of such phenomena in polycrystalline materials is limited, as most studies focus on bicrystal geometries. In this work, we investigate interfacial segregation and subsequent complexion transitions in polycrystalline Cu-Zr alloys using hybrid Monte Carlo/molecular dynamics simulations. No significant change in the grain size or structure is observed upon Zr dopant addition to a pure Cu polycrystal at moderate temperature, where grain boundary segregation is the dominant behavior. Segregation within the boundary network is inhomogeneous, with some boundaries having local concentrations that are an order of magnitude larger than the global value and others having almost no segregation, and changes to physical parameters such as boundary free volume and energy are found to correlate with dopant concentration. Further, another alloy sample is investigated at a higher temperature to probe the occurrence of widespread transitions in interfacial structure, where a significant fraction of the originally ordered boundaries transition to amorphous complexions, demonstrating the coexistence of multiple complexion types, each with their own distribution of boundary chemical composition. Overall, this work highlights that interfacial segregation and complexion structure can be diverse in a polycrystalline network. The findings shown here complement existing computational and experimental studies of individual interfaces and help pave the way for unraveling the complexity of interfacial structure in realistic microstructures.

Environmental and evolutionary factors favouring the coexistence of sarcosaprophagous Calliphoridae species competing for animal necromass

1. Sarcosaprophagous flies from the Calliphoridae family provide clues about the circumstances of death in criminal investigations, and apparently occupy the same ecological niche because they depend on the same ephemeral resource, namely, carrion.2. An empirical study was conducted in southeastern New Brunswick, Canada to identify differences in Hutchinsonian hypervolume/ecological niche that allow for competitive coexistence of calliphorid species. To do this, calliphorids were trapped for a calendar year in urban, periurban, and forest habitats.3. About 20 576 calliphorid specimens distributed among 14 different species were collected. The composition of species assemblages changed with seasons, abiotic factors, habitats, and was related to the evolutionary history of species. Each species had a distinct centroid when their response to study variables was illustrated in canonical space, thus suggesting that their ecological niches differed.4. Examining the Hutchinsonian hypervolumes of these forensically important insects is critical because it expands our knowledge of the factors regulating the activity of calliphorid species, thereby increasing our ability to use these insects in forensic investigations.

Doomed to Repetition? Havana, Washington, Miami, and Moscow, from the Cold War to Today

This paper offers a broad historical overview of US economic sanctions against Cuba, starting with the imposition of the partial trade embargo on 19 October 1960, taking the story up to the present day. Additionally, it develops a comprehensive survey of the numerous scholarly and policy debates which closely follow the changes in United States’ post-Cold War attitudes and actions towards its southern neighbor and which demonstrate the thinking behind centers of power in Washington and Miami related to US’ Cuba policies. The paper also glances over the latest developments under Cuba’s new President Miguel Díaz-Canel and the notable return to the harsh Cold War rhetoric, which transcends the boundaries of the localized Washington-Miami-Havana axis of the past thirty years. Referring to historic patterns, the paper concludes that the conjecture between the recent complication in the US-Cuba relations and Moscow’s ambition to reinstate its erstwhile position as an unavoidable international factor would afford Havana with the opportunity to reclaim once again the dubious honor of becoming one of the focal points in the renewed competitive coexistence between the United States and Russia.

Coexistence of interdependence and competition in adaptive multilayer network

• In the mixed-adaptive model, multiplexing gains the thresholds forward and backward transitions against a monolayer problem. • The hysteresis in a multiplex network is observed at a larger population of competitive units against a single-layer model. • The multiplex configuration is more robust against self-consistent amplification of pre-bifurcation bursts of local coherence. In dynamical networks, the presence of adaptation establishing the relationship between the coherence of local populations and unit’s effective coupling provides the explosive transition — an abrupt transition from incoherence to coherence and vice versa through the hysteresis loop. Explosive transition is even possible under the coexistence of two opposite types of adaptation – interdependence and competition, wherein growing the competitive population dramatically narrows the area of hysteresis. Here, we demonstrate that considering a mixed adaptive model from a multilayer perspective expands the hysteresis region and shifts both forward and backward transition boundaries to the higher values of coupling strength as compared with a monolayer case. We show that this is due to greater robustness of the multilayer network against the intralayer topology and lower sensitivity to the amplification of the pre-bifurcation noise, i.e., spurious fluctuations of local coherence, in the vicinity of a tipping point as opposed to a single-layer network.

Global dynamics for a drug-sensitive and drug-resistant mixed strains of HIV infection model with saturated incidence and distributed delays

In this paper, a drug-sensitive and drug-resistant mixed strains of HIV infection model with saturated incidence and distributed infection delays is proposed. The drug-sensitive strain could mutate and become drug-resistant strain during the process of reverse transcription (i.e., SR conversion in short). The nonnegativity and boundedness of solutions are discussed, by introducing two kinds of principle reproduction numbers, i.e., Rs (the reproduction number induced by drug-sensitive strain of HIV virus) and Rr (the reproduction number induced by drug-resistant strain of HIV virus), the existence of equilibria is also acquired. Using the linearization method and constructing the suitable Lyapunov functionals, the criteria are established on the local and global stability of equilibria (including infection-free, drug-sensitive strain, drug-resistant strain and endemic) based on the composite effects of Rs and Rr. We find that there exist competitive exclusion and coexistence phenomenon between drug-sensitive and drug-resistant strains without SR conversion, while uniform persistence between the two kinds of strains with SR conversion. The theoretical results are illustrated by numerical simulations.

Dynamical behaviors of a classical Lotka–Volterra competition–diffusion–advection system

This paper deals with a two-species competition model in a homogeneous advective environment, where two species are subjected to a net loss of individuals at the downstream end. Under the assumption that the advection and diffusion rates of two species are proportional, we give a basic classification on the global dynamics by employing the theory of monotone dynamical system. It turns out that bistability does not happen, but coexistence and competitive exclusion may occur. Furthermore, we present a complete classification on the global dynamics in terms of the growth rates of two species. However, once the above assumption does not hold, bistability may occur. In detail, there exists a tradeoff between growth rates of two species such that competition outcomes can shift between three possible scenarios, including competitive exclusion, bistability and coexistence. These results show that growth competence is important to determine dynamical behaviors.