Cyclic Dynamics Research Articles

Characterizing the schooling cycle

This paper examines the cyclical dynamics of school participation decision, using data for 16-24-year-olds attending full-time post-compulsory education in the UK in the period from 1995Q1 to 2019Q4. We find evidence of a highly persistent education cycle, largely explained by the business cycle. Importantly, the response of school participation to the business cycle is time-dependent – counter-cyclical in the period around the Great Financial Crisis and pro-cyclical in other years. We propose two channels as predictors of the cyclicality of schooling – the ability-to-pay for further education and the opportunity-cost of spending time in education rather than at work. We also show that the results are heterogeneous by gender, with female choices being more responsive to changes in aggregate macroeconomic conditions than male choices. Timely policy interventions using regular education as a counter-cyclical tool can help prevent persistent or permanent unemployment in the aftermath of a crisis.

ЦИКЛИЧНОСТЬ ЭКОНОМИЧЕСКОЙ ДИНАМИКИ

Cyclical dynamics is a universal form of movement of nature, society and the economy. The specificity of economic dynamics is that it has a more probabilistic character than, for example, natural cycles. It is important to take this fact into account in the process of forecasting economic development. In the modern economy, forecasting plays an essential role, which is due to the practical significance of forecasts. The cyclical type of oscillation is characterized by repeated periods of decline and rise. The uneven development of the economy, reflected in the distribution of dynamic series of statistical data characterizing the results of economic activity for various types of fluctuations in economic dynamics, is a basic condition for the development of management technologies on a state and economic scale. However, in the practice of public administration of national economic complexes and the national economy as a whole, the economic unevenness of economic development is often ignored. The cyclical nature of economic dynamics and the onset of the crisis are determined by the trends in the development of production and the economy as a whole, the state of socio-economic relations, the content and nature of public life. The imbalance of the economic interests of the state and private capital, economic and political elites and citizens can lead to crises in the economy. The peculiarity of cyclicity in the agricultural sector of the Russian economy, the nature and duration of the crisis determine the need for the use of non-standard methods of crisis management, which is facilitated by a comprehensive study of existing problems, the causes of downward trends in economic dynamics and the effectiveness of priority areas of industry development. The latest financial and economic crisis of the world economy, which affected Russia and the most vulnerable sphere of its economy - the agricultural sector, showed that the process of achieving sustainable agricultural development is long and requires effective use of state support measures and various elements of anti–crisis management, the development of tools for diagnosing and forecasting crisis phenomena, the formation of programs for the soft passage of agriculture downward trajectory of the economic cycle. The article discusses the theoretical foundations of the cyclical nature of economic dynamics.

The Cyclical Dynamics of National Income: Understanding the Circular Flow of Income

The Cyclical Dynamics of National Income: Understanding the Circular Flow of Income

Cyclical Dynamics of Money and Debt

Cyclical Dynamics of Money and Debt

The Cyclical Dynamics of National Income: Understanding the Circular Flow of Income in the Philippines

The Cyclical Dynamics of National Income: Understanding the Circular Flow of Income in the Philippines

THE CURRENT CRISIS STAGE OF CIVILIZATIONAL DYNAMICS OF MANKIND

The content of the research problem we have put forward in the article concerns the cyclical dynamics of mankind and its modern crisis milestone. The observation of the process and the deep nature of the formation of the latter summarizes the purpose of this study. The relevance of the problem is dictated by the objective requirement to disclose the deep basis of the crisis manifestations of modern realities. In accordance with the purpose of the study, a number of interconnected research problems were put set forward and solved: theoretical approaches to the cyclical dynamics of civilizations were generalized, the characteristics of their crisis milestones were analyzed which are displayed in the context of modern civilizational realities. To solve the research problems, we used scientific methods of analysis, synthesis, dipping and reengineering, comparative and geographical, theoretical generalization. The theoretical conclusions and proposals obtained from the study can provoke the necessary scientific debate both in the academic theoretical field and become the basis for practical prediction and forecasting of the future development of societies.

Changes in the fauna and distribution of birds of the forest-steppe Trans-Urals in the late XX – early XXI centuries under the influence of natural and anthropogenic factors

The distribution of birds in the West Siberian plain in the western part of the forest-steppe zone (bound east by River Ishim) is very dynamic. Just since the beginning of this century, 16 new breeding species and one possibly breeding species have been discovered in this region. Most of them (76%) are representatives of the Tropical group (5 species) dispersing from the south, as well as the Nomadic (5) and the European (3) types of fauna coming from the south and the west; 3 species belong to the Chinese type of fauna and one – to the Siberian type. Another new species from the Tropical group was recorded as breeding in the last decade of the previous century. The distribution ranges of all 6 representatives of the Tropical group and 2 species of the Nomadic fauna associated with aquatic habitats have expanded northward most over the past 40 years (for 500–600 km). A powerful wave of their dispersal in forest-steppe occurred during the years of maximum filling of water reservoirs in the early 2000s. At the same time, despite the cyclical dynamics of the water level, cyclical processes in the changes of the distribution of limnophile birds are not expressed (analysis of century-long faunal lists shows the cyclical nature of the distribution of no more than 2–3 such species). It is assumed that against the background of intense climate warming most bird species, primarily limnophiles, are not simply redistributing individuals within the ranges, but are expanding their ranges northward, and that expansion will continue in the future. The anthropogenic impact on the regional avifauna is mainly caused by the consequences of the economic crisis in agriculture. In the recent decades, it has been much less obvious than the natural impact.

Numerical response of predator to prey: Dynamic interactions and population cycles in Eurasian lynx and roe deer

AbstractThe dynamic interactions between predators and their prey have two fundamental processes: numerical and functional responses. Numerical response is defined as predator growth rate as a function of prey density or both prey and predator densities [dP/dt = f(N, P)]. Functional response is defined as the kill rate by an individual predator being a function of prey density or prey and predator densities combined. Although there are relatively many studies on the functional response in mammalian predators, the numerical response remains poorly documented. We studied the numerical response of Eurasian lynx (Lynx lynx) to various densities of its primary prey species, roe deer (Capreolus capreolus), and to itself (lynx). We exploited an unusual natural situation, spanning three decades where lynx, after a period of absence in central and southern Sweden, during which roe deer populations had grown to high densities, subsequently recolonized region after region, from north to south. We divided the study area into seven regions, with increasing productivity from north to south. We found strong effects of both roe deer density and lynx density on lynx numerical response. Thus, both resources and intraspecific competition for these resources are important to understanding the lynx population dynamic. We built a series of deterministic lynx–roe deer models, and applied them to the seven regions. We found a very good fit between these Lotka–Volterra type models and the data. The deterministic models produced almost cyclic dynamics or dampened cycles in five of the seven regions. Thus, we documented population cycles in this large predator–large herbivore system, which is rarely done. The amplitudes in the dampened cycles decreased toward the south. Thus, the dynamics between lynx and roe deer became more stable with increasing carrying capacity for roe deer, which is related to higher productivity in the environment. This increased stability could be explained by variation in predation risk, where human presence can act as prey refugia, and by a more diverse prey guild that will weaken the direct interaction between lynx and roe deer.

Contrasting patterns of land-cover change between early and late successional forests in a tropical montane cloud forest area managed under the milpa system

Land cover dynamics (LCD) in areas affected by different management types are hard to predict. Such is the case of tropical montane cloud forest (TMCF) areas in Mexico. The millenary itinerant milpa involves local cyclical deforestation and natural reforestation dynamics with long-lasting fallow periods. Conversely, induced grasslands for cattle, non-traditional maize cultivation with short fallow periods, and sedentary agriculture involve persistent deforestation rates. Also, human density changes could alter LCD. Ignoring such factors may lead to equivocal conclusions. We analyzed LCD using remote sensing analyses with LANDSAT images during two periods (1993–2005, 2005–2014) in a TMCF area in Sierra Norte, Oaxaca, affected by milpas, sedentary agriculture, and grasslands. We divided the study area into six indigenous sub-regions with different human population growth rates (HPG). We identified five land-cover types: mature forests (MF) dominated by TMCF species, early successional pine forests (PF), shrubby fallows (SH), croplands (milpas and more sedentary maize croplands together), and grasslands. We show that: (a) The 1993–2005 period was more variable than the 2005–2014 period, 27 % vs. 21 % of the total area displayed transitions into another class. (b) MF area dominated (277,128 ha), increased from 1993 (64.0 %) to 2014 (67.6 %), and was not statistically associated with HPG. (c) PFs decreased from 27 % in 1993 to 15 % in 2014, and their rate of change was negatively associated with HPG. (d) The total forest area (MF + PF) decreased by 9.3 %. (f) Grasslands, SHs, and croplands fluctuated between periods and sub-regions, but none exceeded 7 % of the total area. (g) Grasslands showed the greatest increase rate, mainly at the expense of forestlands. (h) The grassland and SH increments were positively associated with HPG. The heterogeneity in LCD among periods and sub-regions reveals the relevance of considering temporal and spatial scales within the same region. The persistence of MF and the PF decrease can be ascribed to the disruption of the successional dynamics related to the decline of the traditional milpa enforced by federal and state policies at the beginning of the 21st century, the sedentarization of agriculture, local conservation areas, increases of induced pastures, and human emigration. Although Sierra Norte is an essential reservoir of TMCFs, the decline of the total forest area, particularly secondary forests, is of concern given their roles in resilience and as carbon, culture, and biodiversity reservoirs. Humid mid-elevation areas of Sierra Norte are one of the few examples of mature forest persistence and secondary forest decline.

Forecasting turning points of the Russian economic cycle with leading indicators

In recent decades, predicting turning points of economic cycles (their peaks and troughs) using leading indicators has established itself as a fairly simple, clear and at the same time reliable method. But the world experience has shown that any system of leading indicators requires revision and clarification from time to time. The recent non-economic shocks experienced by the Russian economy have made urgent a full-scale revision of existing leading indicators. The article proposes a methodology for constructing a new index, which, one may hope, will not have the shortcomings of its predecessors. In the process of its construction, the dating of the peaks and troughs associated with previous recessions in the Russian economy was specified; the peculiarities of the cyclical dynamics of several dozens of time series were re-examined. The eight most promising indicators were aggregated into a composite leading indicator (CLI) using two alternative methods; we have chosen the one which is not only easier to use and update, but, apparently, with better predictive properties.

The contribution of evolvability to the eco-evolutionary dynamics of competing species.

Evolvability is the capacity of a population to generate heritable variation that can be acted upon by natural selection. This ability influences the adaptations and fitness of individual organisms. By viewing this capacity as a trait, evolvability is subject to natural selection and thus plays a critical role in eco-evolutionary dynamics. Understanding this role provides insight into how species respond to changes in their environment and how species coexistence can arise and be maintained. Here, we create a G-function model of competing species, each with a different evolvability. We analyze population and strategy (= heritable phenotype) dynamics of the two populations under clade initiation (when species are introduced into a population), evolutionary tracking (constant, small changes in the environment), adaptive radiation (availability of multiple ecological niches), and evolutionary rescue (extreme environmental disturbances). We find that when species are far from an eco-evolutionary equilibrium, faster-evolving species reach higher population sizes, and when species are close to an equilibrium, slower-evolving species are more successful. Frequent, minor environmental changes promote the extinction of species with small population sizes, regardless of their evolvability. When several niches are available for a species to occupy, coexistence is possible, though slower-evolving species perform slightly better than faster-evolving ones due to the well-recognized inherent cost of evolvability. Finally, disrupting the environment at intermediate frequencies can result in coexistence with cyclical population dynamics of species with different rates of evolution.

Front and Back Covers, Volume 39, Number 5. October 2023

Front and back cover caption, volume 39 issue 5IBN KHALDUN AND RE‐TRIBALIZATIONA bust of Ibn Khaldun (1332‐1406), at the entrance of the Kasbah of Bejaia, Algeria. As you gaze upon this scholar, who first delved into the cyclical dynamics of tribes and civilizations, you are not just looking at history — you are looking at a mirror reflecting our modern world. Khaldun's pioneering insights into tribal cohesion (asabiyyah) and its impact on societal rise and fall are not relics of the past; they are prophetic echoes reverberating in today's global landscape.In an increasingly interconnected yet paradoxically fragmented world, the concept of ‘tribalism’ is making a surprising comeback.No longer confined to anthropology textbooks or remote communities, tribalism resurfaces in our political dialogues, social affiliations, and even international relations. But this is not your grandfather's tribalism; it is ‘re‐tribalization’, a modern reimagining of ancient affiliations and loyalties shaping nations and rewriting global equations.In this issue, the first of a two‐part article by Ahmed et al., ‘Re‐tribalization in the 21st century’, peels back the layers of this complex phenomenon. It challenges the conventional wisdom that pits ‘tribalism’ against ‘civilization’, revealing instead a dynamic interplay that influences everything from state governance to globalization. Whether it is the UK Brexit vote, the rise of ethnonationalism in various countries or the enduring conflicts in the Middle East, the fingerprints of tribalism — and its modern avatar, re‐tribalization — are unmistakably present.As we navigate the complexities of a world that is both a ‘global village’ and a patchwork of evolving tribal identities, the concept of re‐tribalization serves as an analytical lens. This resurgence of tribal affiliations is a complex adaptation to the challenges and opportunities of a globalized world. The ancient codes of tribalism are being reinterpreted in the context of modern geopolitics and digital communication. While the old and the new may seem to be in tension, they are part of a complex dynamic that requires scrutiny. The ancient and the modern coexist in a world as fraught with conflict as it is ripe for cooperation.FOOTBALL AND CLIMATE CHANGEOn the dwindling sands of Ariyallur Beach in the coastal hamlet of Ottummal, Malabar, India, children passionately kick a football around, savouring the shrinking space that remains for their cherished sport. Their laughter and shouts echo against a backdrop of rising tides and eroding shores, a poignant reminder of the impermanence of their playground.In this issue, Muhammed Haneefa delves into the heart of this coastal community to explore how the relentless rise in sea levels is not just a geographical alteration but a transformation of a way of life. He uncovers the erosion of subaerial beaches — once the lifeblood of the community's social and cultural fabric — and its devastating impact on leisure activities, most notably the deeply ingrained pastime of football.Haneefa also scrutinizes the local government's ‘managed retreat’ strategy, a well‐intentioned but complex proposal that involves relocating these vulnerable communities away from their endangered coastal homes. While the plan may offer a temporary respite from the encroaching waters, it fails to account for the fisherfolk's profound emotional and cultural ties to their land and traditions.This article serves as a lens through which we can view climate change from the ground up. While satellite images and climatological data may provide a bird's‐eye view of the planet's changing face, it is through the worm's‐eye view of anthropologists and ethnographers like Haneefa that we truly understand the human cost. Here, climate change is not just a statistic or a future projection; it is a lived reality that is reshaping communities, altering identities and challenging the very essence of cultural heritage.

Heat Budget of Sub-Mediterranean Downy Oak Landscapes of Southeastern Crimea

This article presents the findings of a research endeavor focused on the diurnal and seasonal dynamics of heat balance and its constituent elements within an oak forest situated in the expanse of the Karadag Nature Reserve. Computed are the values corresponding to the elements of heat balance, encompassing radiation balance, latent heat fluxes corresponding to heat consumption for evaporation, turbulent heat exchange transpiring within the atmosphere, and heat flux coursing through the soil. The features of changes in the heat balance in two key areas are considered: in the zone of growth of the downy oak forest in an open area and in the forest itself. The study discloses patterns characterizing the apportionment of radiation balance into heat and energetic fluxes within the context of the downy oak landscapes native to the southeastern Crimea. Scrutiny of the data established that a substantial proportion of radiation balance finds application in propelling turbulent heat flux, while a minor share is channeled into processes of evaporation and soil heat flux. Evidenced is that the magnitudes of heat balance components, encompassing radiation balance, latent heat fluxes corresponding to heat consumption for evaporation, turbulent heat exchange transpiring within the atmosphere, and heat flux through the soil within the sub-canopy realm, undergo modifications contingent upon the seasons of the year and the vegetative phases of the downy oak forest. The correlation between air temperature and the constituents of heat balance is subject to analysis both within the confines of the territory in the zone of growth of the downy oak forest in an open area and in the forest itself. Manifest is the constancy of the influence exerted by forest vegetation upon heat balance; nevertheless, the degree of its impact is circumscribed by the cyclical dynamics of foliage upon the trees: a well-developed canopy serves to amplify the influence exerted upon the distribution of heat and energetic fluxes. This study of heat balance and its constituents assumes significance in engendering comprehension regarding the operation of downy oak landscapes that are situated on the periphery of their habitudinal range. Also, it helps to reveal deeper patterns of climate change in forest ecosystems.

Investigating the thermal and chemical kinetic effects of the internal residual on the cyclic dynamics at the dilute limits of a spark-ignition engine

The cyclic variability in the misfire and partial burn regimes of a dilute spark-ignition engine are primarily due to the feed-forward mechanism present in the residual gases. This study experimentally investigates the influence of the specific heat capacity/thermal effect and chemical kinetic effect of the internal residual on the heat release dynamics in the misfire and partial burn regimes of a dilute spark-ignition engine. Each effect is investigated by displacing excess air with bottled N2 and CO. Both short-term and long-term heat release dynamics are analyzed using association rules. Results show both an increased amount of dilution and higher specific heat capacity can result in similar dynamics. It was also found the misfire regime appears to be more sensitive to the chemical kinetic effect than the partial burn regime. Comparison of spark-to-CA05 and spark-to-CA50 between dilution methods was also conducted, where it was found the chemical kinetic effect did tend to reduce both spark-to-CA05 and spark-to-CA50. Overall, results from this study suggest different control strategies may be necessary to effectively mitigate the combustion instabilities when operating in each regime.

Small rodent monitoring at Birkebeiner Road, Norway.

Northern small mammal populations are renowned for their multi-annual population cycles. Population cycles are multi-faceted and have extensive impacts on the rest of the ecosystem. In 2011, we started a student-based research activity to monitor the variation of small rodent density along an elevation gradient following the Birkebeiner Road, in southeast Norway. Fieldwork was conducted by staff and students at the University campus Evenstad, Inland Norway University of Applied Sciences, which has a long history of researching cyclic population dynamics. The faculty has a strong focus on engaging students in all parts of the research activities, including data collection. Small rodents were monitored using a set of snap trap stations. Trapped animals were measured (e.g. body mass, body length, sex) and dissected to assess their reproductive status. We also characterised the vegetation at trapping sites. We provide a dataset of small rodent observations that show fluctuating population dynamics across an elevation gradient (300 m to 1,100 m a.s.l) and in contrasting habitats. This dataset encompasses three peaks of the typical 3-4-year vole population cycles; the number of small rodents and shrews captured show synchrony and peaked in years 2014, 2017 and 2021. The bank vole Myodesglareolus was by far (87%) the most common species trapped, but also other species were observed (including shrews). We provide digital data collection forms and highlight the importance of long-term data collection.

Marine ecosystem models of realistic complexity rarely exhibits significant endogenous non-stationary dynamics

Despite the observation of cyclic and chaotic dynamics in nature, it is still not clear whether this behaviour is inherent to ecological systems or caused by external forcings. Here we explored a set of approximately 210,000 simulations to assess how often a model of realistic complexity exhibits non-stationary dynamics when external perturbations are excluded. Remarkably, less than one third of the population shown non-stationary dynamics and, even when present, fluctuations were rather small. The inherent stability of plankton communities showed to be related to the presence of multiple feedbacks in the food web structure, omnivory, low centre of gravity, and supports the conclusion that food webs of realistic complexity rarely exhibit significant endogenous non-stationary dynamics. Finally, we computed Lyapunov exponents for the non-stationary trajectories, in order to assess in which proportion they were periodic or chaotic, and we concluded that less than 10% of the non-stationary trajectories (3% of the total) showed sensitivities to initial conditions. This further supports the conclusion that complex topology mainly damps endogenous fluctuations in the food web.

Insect Mortality Caused by Baculovirus: a Model of Second-Order Phase Transitions

Baculoviruses, especially prevalent in Lepidoptera, have attracted the most attention as biological insect control agents. Infection with baculoviruses is usually fatal and therefore can affect host population density, especially if virus transmission increases with host density. Lepidoptera larvae show a strong dose-dependent response to pathogens such as baculoviruses, so their response to various pathogen exposures was studied in the present work. Models of virus exposure to insect hosts are usually judged by whether or not they generate cyclical population dynamics of multiple host generations. However, the existing theoretical models based on systems of differential equations are of little use for practical application due to the large number of variables and free parameters. In this regard, the possibility of using a mathematical model for describing the epizootic Malacosoma neustria L. and Lymantria dispar L. under the influence of nuclear polyhedrosis virus is considered. To assess the sensitivity of insects to the effects of baculoviruses, laboratory experiments were carried out on the mortality of caterpillars under various infectious loads. In this paper, we consider the possibility of constructing a model for the lifetime of insects after exposure to baculoviruses as an analogue of a second-order phase transition in physical systems and give estimates of the model parameters for two insect species at different titers of baculoviruses and at different ages of caterpillars. The dependence of the parameters of the proposed model on nuclear polyhedrosis virus strains is shown. The importance of the applied parameters for the organization of forest protection measures is substantiated.

A Baseline Model of Behavioral Political Cycles and Macroeconomic Fluctuations

Although the rational choice approach remains the theoretical modeling paradigm in economics and political sciences, the relevance of behavioral factors such as heuristics and biases has been increasingly acknowledged in both fields over the last decades. Against this background, and in honor the lifetime work of Peter Flaschel, we set up a baseline political-macroeconomic model of the Keynes-Metzler-Goodwin (KMG) variety enhanced with endogenous political choices as in Di Guilmi and Galanis (2021). The mutual feedback between the political and the macroeconomic spheres, generated by our framework, gives rise to cyclical dynamics around moving long-term trends for certain parameter constellations. The results of both the stability analysis and the simulations illustrate the existence of multiple political equilibria in the presence of endogenous electoral presences resulting from the crucial role of income distribution not only as a determinant of aggregate investment and aggregate output, but also, of the political climate.

Observables for cyclic causal set cosmologies

In causal set theory, cycles of cosmic expansion and collapse are modelled by causal sets with ‘breaks’ and ‘posts’ and a special role is played by cyclic dynamics in which the universe goes through perpetual cycles. We identify and characterise two algebras of observables for cyclic dynamics in which the causal set universe has infinitely many breaks. The first algebra is constructed from the cylinder sets associated with finite causal sets that have a single maximal element and offers a new framework for defining cyclic dynamics as random walks on a novel tree. The second algebra is generated by a collection of stem-sets and offers a physical interpretation of the observables in these models as statements about unlabelled stems with a single maximal element. There are analogous theorems for cyclic dynamics in which the causal set universe has infinitely many posts.

Emergence of Punishment in Social Dilemma with Environmental Feedback

Altruistic punishment (or punishment) has been extensively shown as an important mechanism for promoting cooperation in human societies. In AI, the emergence of punishment has received much recent interest. In this paper, we contribute with a novel evolutionary game theoretic model to study the impacts of environmental feedback. Whereas a population of agents plays public goods games, there exists a third-party population whose payoffs depend not only on whether to punish or not, but also on the state of the environment (e.g., how cooperative the agents in a social dilemma are). Focusing on one-shot public goods games, we show that environmental feedback, by itself, can lead to the emergence of punishment. We analyze the co-evolution of punishment and cooperation, and derive conditions for their co-presence, co-dominance and co-extinction. Moreover, we show that the system can exhibit bistability as well as cyclic dynamics. Our findings provide a new explanation for the emergence of punishment. On the other hand, our results also alert the need for careful design of implementing punishment in multi-agent systems, as the resulting evolutionary dynamics can be somewhat complex.