One characteristic of the transition from the Middle Paleolithic to the Upper Paleolithic in Europe was the emergence of representational charcoal drawings and engravings by Aurignacian and Gravettian artists. European Neanderthals never engaged in representational drawing during the Middle and Early Upper Paleolithic, a property that might reflect less developed visuomotor coordination. This article postulates a causal relationship between an evolved ability of anatomically modern humans to throw spears accurately while hunting and their ability to draw representational images from working (...) memory. Unlike Neanderthals, archaic and anatomically modern humans in sub-Saharan Africa adopted longer-range hunting practices using hand-cast spears as a compensation for the emergence of increasingly wary game. For Neanderthals, paleoclimatic fluctuations likely precluded consistent hunting of cold-adapted game, a property making game more approachable for close-range hunting with thrusting spears. As evidence of less historical wariness of humans, many of the species hunted by Neanderthals were eventually domesticated. Due to strong sources of natural selection on archaic and anatomically modern humans for effective hunting, the parietal cortex that integrates visual imagery and motor coordination expanded progressively, yielding the globular shape of the human cranium that is not evident in Neanderthals. To characterize how the cognitive properties employed for throwing spears and drawing line work are similar, the Upper Paleolithic drawings of animals in Chauvet cave, France, are discussed in the speculative context of how these artists engaged simultaneously in overt attention to guide their hand movements and covert attention to their mental images during the drawing process. (shrink)

The article aims to map the contemporary techno-social networks, together with delineation of the algorithmic governmentality, computational unconscious, the epistemic structure of the Eurocentric matrix of power haunted by its own repetition of the constant abyss of horrors, only to search for gestures of resistance. Gestures of resistance, contrary to the false conviction of capitalist realism, can be found everywhere, including in Jordan Peele's Nope (2022). Through a variety of motifs, themes, and cultural and cinematic references, Peele creates a resistance (...) image, i.e., an image that resists the historical trajectory of the violence of the digital colonial matrix of knowledge. In particular with Nope, in which the history of racial violence is disentangled by evoking the relation between the entanglement of capital and epistemic violence embodied in an all-devouring predator UFO. But Nope is also about visualizing silenced histories. Indeed, to strive to capture UFO with the camera is to break away from modernity as a totalizing onto-epistemology and in this register generating a false universal subject of a Man. (shrink)

This paper establishes a model on the upstream and downstream relationship among private enterprises, provincial and local officials, and the central government in the real estate market using the population ecology theory of mutual relations among individual species from the perspective of business ecosystem. A dynamic model is introduced and the complex dynamical behaviors of such a predator-prey model are investigated by means of numerical simulation. The local stability conditions and complex dynamics are investigated, and the existence of chaos is (...) discussed in the sense of Marotto theorem; bifurcation diagrams, Lyapunov exponents, sensitivity analysis for initial values, and time history figure of the system are mapped out and discussed. This shows that there are two routes to complicated dynamics, one of which is the cascade of flip bifurcations resulting in periodic cycles, and the other one is Neimark-Sacker bifurcation which produces attractive invariant closed curves. We arrive at conclusions that the phenomenon of chaos is harmful to private enterprises, and unstable behavior is often unfavorable. Thus, linear feedback control is applied to drive the model to a stable state when the system exhibits chaotic behaviors, achieving the goal of eliminating the negative effects to a large extent. (shrink)

Diffusion plays an essential role in the distribution of predator and prey. We mainly research the diffusion network’s effect on the predator-prey model through bifurcation. First, it is found that the link probability and diffusion parameter can cause Turing instability in the network-organized predator-prey model. Then, the Turing stability region is obtained according to the sufficient condition of Turing instability and the eigenvalues’ distribution. Finally, the biological mechanism is explained through our theoretical results, which are also illustrated by numerical simulation.

In this work, our aim is to investigate the impact of a non-Kolmogorov predator-prey-subsidy model incorporating nonlinear prey refuge and the effect of fear with Holling type II functional response. The model arises from the study of a biological system involving arctic foxes, lemmings, and seal carcasses. The positivity and asymptotically uniform boundedness of the solutions of the system have been derived. Analytically, we have studied the criteria for the feasibility and stability of different equilibrium points. In addition, we have (...) derived sufficient conditions for the existence of local bifurcations of codimension 1. It is also observed that there is some time lag between the time of perceiving predator signals through vocal cues and the reduction of prey’s birth rate. So, we have analyzed the dynamical behaviour of the delayed predator-prey-subsidy model. Numerical computations have been performed using MATLAB to validate all the analytical findings. Numerically, it has been observed that the predator, prey, and subsidy can always exist at a nonzero subsidy input rate. But, at a high subsidy input rate, the prey population cannot persist and the predator population has a huge growth due to the availability of food sources. (shrink)

According to Martha Nussbaum, treating animals justly is a matter of guaranteeing each individual those capabilities up to a minimum threshold that are essential for flourishing as a member of a particular species. Nussbaum’s basic theoretical framework is acceptable; however, a capability which Nussbaum thinks is not essential for the flourishing, the oppor­tunity to kill as a part of exercising predatory instinct, may in fact be essential for predator flourishing. Nussbaum ought to be concerned with the possibility that this capability (...) is essential, since if it is, it is likely that in doing less harm than good we will also be treating some predators unjustly by denying them the opportunity to flourish. (shrink)

In this paper, we propose a time-delayed predator-prey model with Holling-type II functional response, which incorporates the gestation period and the cost of fear into prey reproduction. The dynamical behavior of this system is both analytically and numerically investigated from the viewpoint of stability, permanence, and bifurcation. We found that there are stability switches, and Hopf bifurcations occur when the delay τ passes through a sequence of critical values. The explicit formulae which determine the direction, stability, and other properties of (...) the bifurcating periodic solutions are given by using the normal form theory and center manifold theorem. We perform extensive numerical simulations to explore the impact of some important parameters on the dynamics of the system. Numerical simulations show that high levels of fear have a stabilizing effect while relatively low levels of fear have a destabilizing effect on the predator-prey interactions which lead to limit-cycle oscillations. We also found that the model with or without a delay-dependent factor can have a significantly different dynamics. Thus, ignoring the delay or not including the delay-dependent factor might result in inaccurate modelling predictions. (shrink)

In presence of predator population, the prey population may significantly change their behavior. Fear for predator population enhances the survival probability of prey population, and it can greatly reduce the reproduction of prey population. In this study, we propose a predator-prey fishery model introducing the cost of fear into prey reproduction with Holling type-II functional response and prey-dependent harvesting and investigate the global dynamics of the proposed model. For the system without harvest, it is shown that the level of fear (...) may alter the stability of the positive equilibrium, and an expression of fear critical level is characterized. For the harvest system, the existence of the semitrivial order-1 periodic solution and positive order- q periodic solution is discussed by the construction of a Poincaré map on the phase set, and the threshold conditions are given, which can not only transform state-dependent harvesting into a cycle one but also provide a possibility to determine the harvest frequency. In addition, to ensure a certain robustness of the adopted harvest policy, the threshold condition for the stability of the order- q periodic solution is given. Meanwhile, to achieve a good economic profit, an optimization problem is formulated and the optimum harvest level is obtained. Mathematical findings have been validated in numerical simulation by MATLAB. Different effects of different harvest levels and different fear levels have been demonstrated by depicting figures in numerical simulation using MATLAB. (shrink)

We model the evolution of international conflict as a game of sequential decisions and show that arms races are neither necessary nor sufficient for peace or war. Peaceful intentions are not adequate to insure peace, even when both rivals wish to avoid violence. Peaceful intentions together with complete information are sufficient for peace. A preference for forcefully pursuing foreign policy goals also is not sufficient to preclude the peaceful resolution of disputes, and this is true even if there is (...) complete information. In some circumstances, the absence of an arms race can precipitate violence, even giving the military advantage to a nation that unilaterally stopped getting ready for a war it would initiate. Finally, we also show that empirical research is likely to be biased in favor of the hypothesis that deterrence leads to peace. (shrink)

Complexity is pleased to announce the installment of Prof Hiroki Sayama as its new Chief Editor. In this Editorial, Prof Sayama describes his feelings about his recent appointment, discusses some of the journal’s journey and relevance to current issues, and shares his vision and aspirations for its future.

In this paper I propose a reinforcement learning model for a predator preying upon two types of prey, the unpalatable (noxious) models, and the palatable mimics. The latter type of prey resembles the models in appearance so as to derive some protection from the predator who must avoid the unpalatable models. Essentially the predator is treated as a learning automaton adopting a simple reinforcement learning strategy in order to increase its consumption of palatable prey and reduce the consumption of unpalatable (...) ones. The populations of both mimics and models are assumed to grow logistically. (shrink)

We model the evolution of international conflict as a game of sequential decisions and show that arms races are neither necessary nor sufficient for peace or war. Peaceful intentions are not adequate to insure peace, even when both rivals wish to avoid violence. Peaceful intentions together with complete information are sufficient for peace. A preference for forcefully pursuing foreign policy goals also is not sufficient to preclude the peaceful resolution of disputes, and this is true even if there is (...) complete information. In some circumstances, the absence of an arms race can precipitate violence, even giving the military advantage to a nation that unilaterlaly stopped getting ready for a war it would initiate. Finally, we also show that empirical research is likely to be biased in favor of the hypothesis that deterrence leads to peace. (shrink)

This paper presents the intelligent virtual animals that inhabit Omosa, a virtual learning environment to help secondary school students learn how to conduct scientific inquiry and gain concepts from biology. Omosa supports multiple agents, including animals, plants, and human hunters, which live in groups of varying sizes and in a predator-prey relationship with other agent types (species). In this paper we present our generic agent architecture and the algorithms that drive all animals. We concentrate on two of our animals to (...) present how different parameter values affect their movements and inter/intra-group interactions. Two evaluations studies are included: one to demonstrate the effect of different components of our architecture; another to provide domain expert validation of the animal behavior. (shrink)

The main concern of this paper is to study the dynamic of a predator–prey system with diffusion. It incorporates the Holling-type-II and a modified Leslie–Gower functional responses under Robin boundary conditions. More concretely, we study the dissipativeness of the system by using the comparison principle, and we derive a criteria for permanence and for predator extinction.

Spatial predator-prey models have been studied by researchers for many years, because the exact distributions of the population can be well illustrated via pattern formation. In this paper, amplitude equations of a spatial Holling–Tanner predator-prey model are studied via multiple scale analysis. First, by amplitude equations, we obtain the corresponding intervals in which different kinds of patterns will be onset. Additionally, we get the conclusion that pattern transitions of the predator are induced by the increasing rate of conversion into predator (...) biomass. Specifically, pattern transitions of the predator between distinct Turing pattern structures vary in an orderly manner: from spotted patterns to stripe patterns, and finally to black-eye patterns. Moreover, it is discovered that pattern transitions of prey can be induced by cross-diffusion; that is, patterns of prey transmit from spotted patterns to stripe patterns and finally to a mixture of spot and stripe patterns. Meanwhile, it is found that both effects of cross-diffusion and interaction between the prey and predator can lead to the complicated phenomenon of dynamics in the system of biology. (shrink)

Despite progress in negotiating treaties to ban deployment of particular classes of weapons, such as the Intermediate Nuclear Forces Treaty, the "qualitative" arms race remains largely uncontrolled. Supposed theoretical obstacles, based on various versions of technological determinism, need not be a barrier to practical efforts, however. The reasoning usually cited to explain the competition does not preclude agreement to control it. The varcous perspectives on weapons procurement—realist, action-reaction, bureaucratic politics, technological imperative, and economic—are, as the case of the (...) Strategic Defense Initiative indicates, all subordinate to the "primacy of politics. " Given political will, even the qualitative arms race is amenable to control. (shrink)

By using interactive computer graphics (ICG), it is possible to discuss the numerical aspects of some arms race issues with more specificity and in a visual way. The number of variables involved in these issues can be quite large; computers operated in the interactive, graphical mode, can allow exploration of the variables, leading to a greater understanding of the issues. This paper will examine some examples of interactive computer graphics: (1) The relationship between silo hardening and the accuracy, (...) yield, and reliability of ICBMs; (2) Target vulnerability (Minuteman, Dense Pack); (3) Counterforce vs. countervalue weapons; (4) Civil defense; (5) Gravitational bias error; (6) MIRV; (7) National vulnerability to a preemptive first strike; (8) Radioactive fallout; and (9) Digital image processing with charge-coupled devices. (shrink)

This paper deals with designing a harvesting control strategy for a predator–prey dynamical system, with parametric uncertainties and exogenous disturbances. A feedback control law for the harvesting rate of the predator is formulated such that the population dynamics is asymptotically stabilized at a positive operating point, while maintaining a positive, steady state harvesting rate. The hierarchical block strict feedback structure of the dynamics is exploited in designing a backstepping control law, based on Lyapunov theory. In order to account for (...) unknown parameters, an adaptive control strategy has been proposed in which the control law depends on an adaptive variable which tracks the unknown parameter. Further, a switching component has been incorporated to robustify the control performance against bounded disturbances. Proofs have been provided to show that the proposed adaptive control strategy ensures asymptotic stability of the dynamics at a desired operating point, as well as exact parameter learning in the disturbance-free case and learning with bounded error in the disturbance prone case. The dynamics, with uncertainty in the death rate of the predator, subjected to a bounded disturbance has been simulated with the proposed control strategy. (shrink)

Large-scale weapons systems have increasingly become part of a patronage system justified by claims about national defense. American politics tends to proceed by distribution, redistribution, and compromise. The disjunction between the "virtually" autonomous processes of worldwide weapons innovation and American incrementalism lead to a potentially disastrous situation. This situation is characterized by potential chaos in the integration of complex, interdependent combat and communication systems as well as a mindless arms race that seems to defy political control. A modest (...) proposal is made to suggest a potential bureaucratic change agent. (shrink)

According to resource limitation, a more realistic pest management is that the impulsive control actions should be adjusted according to the densities of both pest and natural enemy in the field, which result in nonlinear impulsive control. Therefore, we have proposed a Beddington–DeAngelis interference predator-prey model concerning integrated pest management with both density-dependent pest and natural enemy population. We find that the pest-eradication periodic solution is globally stable if the impulsive period is less than the critical value by Floquet theorem. (...) The condition of permanent is established, and a stable positive periodic solution appears via a supercritical bifurcation by bifurcation theorem. Finally, in order to investigate the effects of those nonlinear control strategies on the successful pest control, the bifurcation diagrams showed that the model exists with very complex dynamics. Consequently, the resource limitation may result in pest outbreak in complex ways, which means that the pest control strategies should be carefully designed. (shrink)

This paper investigates a stochastic two-patch predator-prey model with ratio-dependent functional responses. First, the existence of a unique global positive solution is proved via the stochastic comparison theorem. Then, two different methods are used to discuss the long-time properties of the solutions pathwise. Next, sufficient conditions for extinction and persistence in mean are obtained. Moreover, stochastic persistence of the model is discussed. Furthermore, sufficient conditions for the existence of an ergodic stationary distribution are derived by a suitable Lyapunov function. Next, (...) we apply the main results in some special models. Finally, some numerical simulations are introduced to support the main results obtained. The results in this paper generalize and improve the previous related results. (shrink)

This paper investigates the diffusive predator-prey system with nonmonotonic functional response and fear effect. Firstly, we discussed the stability of the equilibrium solution for a corresponding ODE system. Secondly, we established a priori positive upper and lower bounds for the positive solutions of the PDE system. Thirdly, sufficient conditions for the local asymptotical stability of two positive equilibrium solutions of the system are given by using the method of eigenvalue spectrum analysis of linearization operator. Finally, the existence and nonexistence of (...) nonconstant positive steady states of this reaction-diffusion system are established by the Leray–Schauder degree theory and Poincaré inequality. (shrink)

One of the most efficient predator-prey models with spatial effects is the one with ratio-dependent functional response. However, there is a need to further explore the effects of spatial motion on the dynamic behavior of population. In this work, we study a ratio-dependent predator-prey model with diffusion terms. The aim of this work is to investigate the changes in predator’s distribution in space as the prey populations change their mobility. We observe that the frequency diffusion of the prey gives rise (...) to the sparse density of the predator. Moreover, we also observe that the increasing rate of the conversion into predator biomass induces pattern transitions of the predator. Specifically speaking, Turing pattern of the predator populations goes gradually from a spotted pattern to a black-eye pattern, with the intermediate state being the mixture of spot and stripe pattern. The simulation results and analysis of this work illustrate that the diffusion rate and the real intrinsic factor influence the persistence of the predator-prey system mutually. (shrink)

We study the effects of density dependent migrations on the stability of a predator-prey model in a patchy environment which is composed with two sites connected by migration. The two patches are different. On the first patch, preys can find resource but can be captured by predators. The second patch is a refuge for the prey and thus predators do not have access to this patch. We assume a repulsive effect of predator on prey on the resource patch. Therefore, when (...) the predator density is large on that patch, preys are more likely to leave it to return to the refuge. We consider two models. In the first model, preys leave the refuge to go to the resource patch at constant migration rates. In the second model, preys are assumed to be in competition for the resource and leave the refuge to the resource patch according to the prey density. We assume two different time scales, a fast time scale for migration and a slow time scale for population growth, mortality and predation. We take advantage of the two time scales to apply aggregation of variables methods and to obtain a reduced model governing the total prey and predator densities. In the case of the first model, we show that the repulsive effect of predator on prey has a stabilizing effect on the predator-prey community. In the case of the second model, we show that there exists a window for the prey proportion on the resource patch to ensure stability. (shrink)

ABSTRACT This paper considers the four ways that the concept of ‘irrationality’ has been employed by members of the European peace movement in their evaluation of current bloc tensions. Against Bernard Williams who has recently taken issue with the peace movement's alleged tendency to dismiss political realities, the present author argues that the use of the language of irrationality reveals just the opposite orientation. Finally, it is argued that although the language of irrationality constitutes a powerful descriptive and normative instrument, (...) as an explanation of the Cold War it is a nonstarter. (shrink)

This article questions the ability of strategic planners to assess adequately the kinds of weapons development and deployment decisions they make, given that the strategic weapons system lacks any usable definition of system failure. Lacking a coherent understanding of system failure means that the positive feedback loops within the system are unrestrained by effective negative feedback In such circumstances, it is not surprising that subunits of the larger system substitute definitions of success for the subunit for definitions applicable to the (...) total system. (shrink)

This article defends the view that markets in education need to be restricted, in light of the problem posed by what I call the ‘educational arms race’. Markets in education have a tendency to distort an important balance between education’s role as a gatekeeper – its ‘screening’ function – and its role in helping children develop as part of a preparation for adult life. This tendency is not merely a contingent fact about markets: It can be traced to (...) ways in which education is a partly positional good and how markets respond to demand for positional goods over non-positional goods. The problem with arms races is that they allow markets to facilitate wider use of defection in a collective action problem. Using these claims, I argue that markets in education have a distinctive tendency to become objectionably exploitative. I conclude by applying some of my conclusions to illuminate various egalitarian claims about justice in education. (shrink)

Theoretical and experimental studies on prey–predator systems where predator is supplied with alternate sources of food have received significant attention over the years due to their relevance in achieving biological conservation and biological control. Some of the outcomes of these studies suggest that with appropriate quality and quantity of additional food, the system can be steered towards any desired state eventually with time. One of the limitations of previous studies is that the desired state is reached asymptotically, which makes the (...) outcomes not easily applicable in practical scenarios. To overcome this limitation, in this work, we formulate and study optimal control problems to achieve the desired outcomes in minimum (finite) time. We consider two different models of additional food provided prey–predator systems involving Holling type IV functional response (with inhibitory effect of prey). In the first scenario, additional food is incorporated implicitly into the predator’s functional response with a possibility of achieving biological conservation through co-existence of species and biological control by maintaining prey at a level that is least harmful to the system. In the second, the effect of additional food is incorporated explicitly into the predator’s compartment with the goal of pest management by maintaining prey density at a very minimal damaging level. For both cases, appropriate optimal control strategies are derived and the theoretical findings are illustrated by numerical simulations. We also discuss the ecological significance of the theoretical findings for both models. (shrink)

Traditional concern for the gradual, incremental effects of climate change remains; but now greater attention is being paid to the possibility of breaching major thresholds in the climate system with catastrophic consequences. It might be thought that the potential for abrupt climate change (a) undermines the usual (economic, psychological, and intergenerational) analyses of the climate change problem, and (b) in doing so helps us to act. Against this, I argue both that much of the psychological and intergenerational analyses remains in (...) place, and that abrupt climate change may make action more difficult, perhaps even setting off an intergenerational arms race. (shrink)