Self-organizing Complex Research Articles

From hydrodynamics to dipolar colloids: Modeling complex interactions and self-organization with generalized potentials.

The self-organization of clusters of particles is a fundamental phenomenon across various physical systems, including hydrodynamic and colloidal systems. One example is that of dense spherical particles submerged in a viscous fluid and subjected to horizontal oscillations. The interaction of the particles with the oscillating flow leads to the formation of one-particle-thick chains or multiple-particle-wide bands, both oriented perpendicular to the oscillation direction. In this study, we model the hydrodynamic interactions between such particles and parallel chains using simplified potentials. We first focus on the hydrodynamic interactions between chains, which we characterize using data from fully resolved numerical simulations. Based on these interactions, we propose a simplified model potential, called the Siren potential, which combines the representative hydrodynamic interactions: short-range attraction, mid-range repulsion, and long-range attraction. Through one-dimensional Monte Carlo simulations, we successfully replicate the characteristic patterns observed in hydrodynamic experiments and draw the phase diagram for the model potential. We further extend our analysis to two-dimensional systems, introducing a dipole-capillary model potential that accounts for both chain formation and Siren-like chain interactions. This potential is based on a system with colloidal particles at an interface, where chain formation is driven by an external electric field that induces a dipole moment parallel to the interface in each particle. The capillary force contributes the long-range attraction. Starting with parallel chains, the patterns in the two-dimensional Monte Carlo simulations of this colloidal system are similar to those observed in the hydrodynamic experiments. However, we identify that nonlinear interactions are important for some distinct steps in the chain formation. Still, the model potentials help clarify the dynamic behavior of the particles and chains due to the complex interactions encountered in both hydrodynamic and colloidal systems, drawing parallels between them.

The WAVE complex forms linear arrays at negative membrane curvature to instruct lamellipodia formation.

Cells generate a wide range of actin-based membrane protrusions for various cell behaviors. These protrusions are organized by different actin nucleation promoting factors. For example, N-WASP controls finger-like filopodia, whereas the WAVE complex controls sheet-like lamellipodia. These different membrane morphologies likely reflect different patterns of nucleator self-organization. N-WASP phase separation has been successfully studied through biochemical reconstitutions, but how the WAVE complex self-organizes to instruct lamellipodia is unknown. Because WAVE complex self-organization has proven refractory to cell-free studies, we leverage in vivo biochemical approaches to investigate WAVE complex organization within its native cellular context. With single molecule tracking and molecular counting, we show that the WAVE complex forms highly regular multilayered linear arrays at the plasma membrane that are reminiscent of a microtubule-like organization. Similar to the organization of microtubule protofilaments in a curved array, membrane curvature is both necessary and sufficient for formation of these WAVE complex linear arrays, though actin polymerization is not. This dependency on negative membrane curvature could explain both the templating of lamellipodia and their emergent behaviors, including barrier avoidance. Our data uncover the key biophysical properties of mesoscale WAVE complex patterning and highlight an integral relationship between NPF self-organization and cell morphogenesis.

Power-law distributions of urban tree cover

Many large-scale systems in nature and society are deemed to be exhibiting characteristics of self-organized criticality (SOC), a dynamical state that, among others, produces robust power-law or other heavy-tailed statistics despite not having any set of fine-tuned parameters. However, many of these systems are also affected by human activities, leading to the simultaneous action of self-organization and human intervention. In this work, we extract the geographical areas of tree-covered greeneries in a highly-urbanized setting and show the emergence of stable power-law tails in their distributions despite the large differences in the conditions of the cities considered. The result shows that while anthropogenic factors have steadily influenced the natural environment, especially in the urban setting, these systems still exhibit complex self-organization.

ORGANIZATIONAL THEORETICAL APPROACHES TO SUSTAINABILITY IN A COMPLEX ENVIRONMENT

ABSTRACT: Complexity and Sustainable Development constitute a framework that challenges the evolution of current socioeconomic systems and, therefore, of organizations, which must gradually adapt to changes, transform, and be part of them. This reality must be accompanied by an adequate theoretical framework capable of supporting and responding to organizational needs, investigating new organizational forms and new forms of interaction with the environment. Bibliometric analysis has been carried out to clarify the theoretical roots and most relevant documents that support the current organizational theoretical framework between 1990 and 2022 on the Web of Science database, revealing theoretical foundations focused on Stakeholders, the Paradox, organizational resources and capabilities, complexity, and institutions. On the other hand, and closely related to the theoretical approaches, the topics of interest have focused on corporate social responsibility, business Sustainability, entrepreneurship, complex adaptive systems, emergency, resilience, and self-organization. Keywords: bibliometric analysis, organization, organizational theory, sustainability, complexity, environment, systemic view

Alkyl quinolones mediate heterogeneous colony biofilm architecture that improves community-level survival.

Bacterial communities exhibit complex self-organization that contributes to their survival. To better understand the molecules that contribute to transforming a small number of cells into a heterogeneous surface biofilm community, we studied acellular aggregates, structures seen by light microscopy in Pseudomonas aeruginosa colony biofilms using light microscopy and chemical imaging. These structures differ from cellular aggregates, cohesive clusters of cells important for biofilm formation, in that they are visually distinct from cells using light microscopy and are reliant on metabolites for assembly. To investigate how these structures benefit a biofilm community we characterized three recurrent types of acellular aggregates with distinct geometries that were each abundant in specific areas of these biofilms. Alkyl quinolones (AQs) were essential for the formation of all aggregate types with AQ signatures outside the aggregates below the limit of detection. These acellular aggregates spatially sequester AQs and differentiate the biofilm space. However, the three types of aggregates showed differing properties in their size, associated cell death, and lipid content. The largest aggregate type co-localized with spatially confined cell death that was not mediated by Pf4 bacteriophage. Biofilms lacking AQs were absent of localized cell death but exhibited increased, homogeneously distributed cell death. Thus, these AQ-rich aggregates regulate metabolite accessibility, differentiate regions of the biofilm, and promote survival in biofilms.IMPORTANCEPseudomonas aeruginosa is an opportunistic pathogen with the ability to cause infection in the immune-compromised. It is well established that P. aeruginosa biofilms exhibit resilience that includes decreased susceptibility to antimicrobial treatment. This work examines the self-assembled heterogeneity in biofilm communities studying acellular aggregates, regions of condensed matter requiring alkyl quinolones (AQs). AQs are important to both virulence and biofilm formation. Aggregate structures described here spatially regulate the accessibility of these AQs, differentiate regions of the biofilm community, and despite their association with autolysis, correlate with improved P. aeruginosa colony biofilm survival.

Self-organization of PIP3 waves is controlled by the topology and curvature of cell membranes

Phosphatidylinositol (3,4,5)-trisphosphate (PIP3) is a signaling lipid on the plasma membrane that plays a fundamental role in cell signaling with a strong impact on cell physiology and diseases. It is responsible for the protruding edge formation, cell polarization, macropinocytosis, and other membrane remodeling dynamics in cells. It has been shown that the membrane confinement and curvature affects the wave formation of PIP3 and F-actin. But, even in the absence of F-actin, a complex self-organization of the spatiotemporal PIP3 waves is observed. In recent findings, we have shown that these waves can be guided and pinned on strongly bended Dictyostelium membranes caused by molecular crowding and curvature-limited diffusion. Based on these experimental findings, we investigate the spatiotemporal PIP3 wave dynamics on realistic three-dimensional cell-like membranes to explore the effect of curvature-limited diffusion, as observed experimentally. We use an established stochastic reaction-diffusion model with enzymatic Michaelis-Menten-type reactions that mimics the dynamics of Dictyostelium cells. As these cells mimic the three-dimensional shape and size observed experimentally, we found that the PIP3 wave directionality can be explained by a Hopf-like and a reverse periodic-doubling bifurcation for uniform diffusion and curvature-limited diffusion properties. Finally, we compare the results with recent experimental findings and discuss the discrepancy between the biological and numerical results.

Microdischarge dynamics of volume DBD under the natural convection airflow

The dielectric barrier discharge (DBD) at ambient air conditions exhibits discrete structure and contains thin microdischarge plasma filaments. Understanding the formation, self-interaction, and dynamics of such filaments is crucial towards the generation of uniform diffuse-like DBD in air, and also for the study of the memory effects and self-organized complex patterns. In this paper, the impact of natural convective flow, driven by the temperature gradient between self-heated discharge cell electrodes and ambient air, on the collective dynamics of microdischarges was studied in parallel-plate volume dielectric barrier discharge for the different geometrical arrangements. The horizontal arrangement corresponds to the parallel direction of discharge propagation and convective flow, while in the vertical arrangement buoyancy flow transverse to the discharge propagation column. For the horizontal arrangement, the randomly directed motion of microdischarges was observed. While at the vertical arrangement of the discharge cell, the buoyancy flow initiates the directed motion of the microdischarges following the gas flow. The continuous self-heating of the barrier electrodes during the DBD operation leads to a larger thermal gradient and increasing in the microdischarge channels. The larger thermal gradient results in a more pronounced directed motion of microdischarges with a higher velocity. The velocity of convective flow in the discharge gap was estimated by the simulation and compared with the mean velocity of MD channels obtained by the particle image velocimetry method.

Thermodynamics of Life as a Speculative Model for Planetary Technology

Originating from nineteenth century physics, the concept of entropy—a measure of disorder, randomness, and/or the dissipation of useful energy—underlay a cosmology where order and complexity were seen as highly improbable phenomena in a universe tending toward chaos and disorganisation. Nearly a century later, theoretical frameworks were developed for understanding the production of entropy as an enabling feature of self-organized complexity in the natural world. These ideas would contribute to establishing connections between the origins, development, and evolution of life and the principles of a thermodynamic universe. For some, they also supplied the conceptual foundations for theorizing about a universal natural tendency driving the development of increasingly complex and ordered systems which amplify processes of entropy production and energy dissipation and dispersal. In this paper I chart a path through the aforementioned ideas and present their relevance in framing a relationship between our technological civilization and the Earth system. I then speculate about the prospect of a technosphere whose constitution and activity are aligned with thermodynamic principles of dissipation and entropy-production, drawing on theoretical biology and recent developments in bioengineering to envision a paradigm where technology becomes living matter itself.

Manipulation of self-organized multi-vortical states in active magnetic roller suspensions

Ensembles of active magnetic colloids demonstrate complex collective behavior and self-organization when driven out of equilibrium by external magnetic fields. The interplay between magnetic and hydrodynamic interactions often result in spontaneous self-assembly and the emergence of localized vortices in ensembles of ferromagnetic rollers. We report experimental and computational study of the self-organized multi-vortical state in ensembles of magnetic rollers under the imposed external confining potential realized by patterned substrates. We explore the behavior of the system on a substrate patterned with shallow wells ordered in a lattice with square symmetry and lattice spacing smaller than the wells’ diameter. We demonstrate, that ensembles of active magnetic rollers evolve in response to changes in the geometry of the confining lattice from a globally correlated state characterized by anti-ferromagnetic vortex ordering to a state with rapidly changing particle flows and self-organized vortical states with a lattice constant larger than one of the confining pattern. Our experimental observations are accompanied by numerical simulations based on phenomenological coarse grained particle dynamics coupled to Navier–Stokes hydrodynamics in shallow water approximation. The reported results provide insights into the collective behavior of active magnetic rollers under confinement and suggest strategies for the manipulation of collective dynamic states in active magnetic liquids.

Is immunology doing well? A look at 100 immune-mediated inflammatory diseases for 100 years of the Journal.

It is now 60 years since Ian Mackay and Macfarlane Burnet published their seminal text "The Autoimmune Diseases" in which they examined the full scope of human inflammatory pathology as a manifestation of the underlying structure and function of the immune system. Here I revisit this approach to ask to what extent has the promise of Mackay and Burnet's work been exploited in clinical medicine as currently practiced. In other words, is immunology doing well? Despite spectacular headline contributions of immunology in clinical medicine, I present evidence suggesting a performance ceiling in our capacity to answer the relatively straightforward questions that patients frequently ask about their own diseases and find that this ceiling exists across almost all of the 100 immune-mediated inflammatory diseases examined. I propose that these questions are difficult, not so much because the immune system is overwhelmingly complex but rather that we have more to learn about the relatively simple agents and rules that may underpin self-organizing complex interacting systems as revealed in studies from other disciplines. The way that the immune system has evolved to exploit the ancient machinery determining three independent cell fate timers as described in this Journal would be a great place to start to decode the self-organizing principles that underpin the emergent pathology that we observe in the clinic.

Is housing price distribution across cities, scale invariant? Fractal distribution of settlements' house prices as signature of self-organized complexity

Locations and sizes of settlements within regions often exhibit a self-organized central place pattern, where larger settlements are encircled by smaller ones, with the former more set apart. This hierarchical spatial pattern is displayed by the fractal signature of the power law typical of the rank-size distribution of settlements. Is a similar pattern also revealed in the housing prices across settlements? An empirical analysis on the almost 8000 Italian municipalities, whose residential population varies between 33 and ∼3 million, shows that, for 15 out of 20 regions, the upper tails rank-house price distribution of settlements is plausibly following a power law. This result discloses a universality in the function behaviour: a scale invariance. The average scaling parameters have been estimated via Maximum Likelihood Estimator and Kolmogorov–Smirnov statistics, and the goodness-of-fit assessed via bootstrapping. Ordinary Least Squares regressions have also been used for comparative purposes. In average, Maximum Likelihood Estimator found a scaling parameter of 4.4. Namely, doubling the rank of the settlement (in terms of housing price), its housing price decreases by 15 %: between the settlement with the highest average house prices (ranked 1), and the settlement with the second highest average house prices (ranked 2), there is a 15 % difference in the average house prices. Idem between the ranked 5 and 10, 10 and 20 … it does not matter; it is a universal behavioural pattern whose scale invariance suggests a self-organized complexity in the phenomena behind it.

Globally correlated states and control of vortex lattices in active roller fluids

Active fluids demonstrate complex collective behavior and self-organization often resulting in the emergence of localized vortices. We report on a combined experimental and computational study of the spontaneous formation of globally correlated vortex lattices formed in active roller fluids. The vortices are comprised of active ferromagnetic rollers placed on a patterned substrate promoting localization of self-organized vortices in a lattice with square symmetry. Each individual vortex spontaneously selects its chiral state (clockwise or counterclockwise). Nevertheless, confined to a square lattice, an ensemble of interacting active vortices is capable of developing correlations between chiral states of neighboring vortices. We show that such ensembles of active vortices can spontaneously evolve towards a globally correlated state with the antiferromagnetic ordering of their vorticities. We explore the correlations between chiral states of neighboring vortex pairs in response to changes in the geometry of the confining lattice. The results are supported by numerical simulations based on phenomenological coarse grained particle dynamics coupled to shallow water Navier-Stokes hydrodynamics. We show that these ordered vortex lattices formed by magnetic rollers have the ability to self-heal the antiferromagnetic order and stabilize individual vortical states in the activity regimes beyond optimal conditions for the collective vortex states. The results provide insights into the collective behavior of active magnetic roller fluids in the presence of geometrical confinement.

Stimuli-Responsive Principles of Supramolecular Organizations Emerging from Self-Assembling and Self-Organizable Dendrons, Dendrimers, and Dendronized Polymers.

All activities of our daily life, of the nature surrounding us and of the entire society and its complex economic and political systems are affected by stimuli. Therefore, understanding stimuli-responsive principles in nature, biology, society, and in complex synthetic systems is fundamental to natural and life sciences. This invited Perspective attempts to organize, to the best of our knowledge, for the first time the stimuli-responsive principles of supramolecular organizations emerging from self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers. Definitions of stimulus and stimuli from different fields of science are first discussed. Subsequently, we decided that supramolecular organizations of self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers may fit best in the definition of stimuli from biology. After a brief historical introduction to the discovery and development of conventional and self-assembling and self-organizable dendrons, dendrimers, and dendronized polymers, a classification of stimuli-responsible principles as internal- and external-stimuli was made. Due to the enormous amount of literature on conventional dendrons, dendrimers, and dendronized polymers as well as on their self-assembling and self-organizable systems we decided to discuss stimuli-responsive principles only with examples from our laboratory. We apologize to all contributors to dendrimers and to the readers of this Perspective for this space-limited decision. Even after this decision, restrictions to a limited number of examples were required. In spite of this, we expect that this Perspective will provide a new way of thinking about stimuli in all fields of self-organized complex soft matter.

Resilience Thinking and Landscape Complexity in the Basentello Valley (BA, MT), c. AD 300–800

Archaeological data for the transformation of late Roman rural landscapes in Southern Italy over the sixth to eighth centuries AD are often meagre. This record often provides little explanatory power in the context of understanding the collapse of Roman political and economic hegemony and the framework for the regeneration of these relationships in the early medieval countryside. Resilience thinking offers a robust suite of heuristics to help guide both method and theory in understanding the key socio-environmental relationships involved in this transformative process based on limited material evidence. Through insights gained from developing a panarchic perspective of the Basentello landscape between AD 300 and 800, both capacities for and strategies of resilience to landscape-scale shocks and stressors emerge as key patterns in this collapse process. To explain how these patterns emerge, resilience thinking employs narratives from complexity science by framing landscapes as self-organizing complex adaptive systems. It is through appreciating this complexity that archaeologists can revolutionize how we understand landscape-scale transformations, the role of resilience in landscape history and, more broadly, the nature of societal collapse.

Regional varieties and diachronic changes in Chinese political discourse

The present paper explores the synchronic variations and diachronic changes in political discourses in Hong Kong (HK) and in Mainland of People’s Republic of China (PRC). The relationship between lengths of linguistic constructs and their immediate constituents (including sentences and clauses, and clauses and words) are fitted using the function y = axb based on the Menzerath–Altmann (MA) law to capture the characteristics of language as self-organizing complex systems. We found that the two fitted parameters a and b, as distinctive characteristics of complex systems, can distinguish two regional variants of political speeches from HK and PRC over different periods in time. We also found that the same parameters can capture language changes between different periods of political speeches from the PRC. More specifically, we found that regional variations and historical changes show different degrees of salience at different constituency levels. In addition, we found compounding effects between historical change and regional variations. That is, the two regional variants of political speeches are closer to each other at the earliest diachronic period as compared with the latter two periods, as represented by the fitted parameters of the relationship between sentence and clause lengths. Our results provide strong support for the hypothesis for the MA Law capturing the characteristics of language as a complex self-organizing system, as the two fitted parameters account for the interaction of diachronic language change and synchronic variation.

Self-Organization of Diverse Directional Hierarchical Networks in Simple Coupled Maps with Connection Changes

We comprehensively studied the morphology of the self-organized effective network structures that form in simple coupled maps with interelement synchronization-dependent connection changes. Based on the parameter values, the spontaneous formation of four types of directional hierarchical networks, named pair-driven networks, loop-driven networks, hidden trio-driven networks, and hidden community-driven networks, was observed. This study provides novel insights into the self-organized complex networks that form in neural networks, various other biological networks, and social networks.

COMPLEX TECHNOLOGY AS A MEANS OF FORMING A HEALTH-SAVING POSITION OF MEDICAL UNIVERSITY STUDENTS

The article discusses the content components of a complex technology, implemented in the formation of a health-preserving position among students of medical universities, the concept of health preservation is presented. The aim of the research is to develop a structural model of the methodology for teaching health-preserving technologies. The following methods were used in the work: analysis, synthesis, generalization, systematization, comparison, modeling. Particular attention is paid to the author's interpretation of the definition of the concepts of "integrated technology" and "health-preserving position". An important side of understanding the health-preserving position of students is the need to be aware of their behavior, in the reflection of their own activities, which is the most important task in the education system. For the purposes of the study, the ideas presented by G.P. Shchedrovitsky, who considers reflection as a form of thought activity based on the systemic-thought-activity approach [Shchedrovitsky 2005]. The study used technology, taking into account the physiological and personal characteristics of students; system-activity, anthropological, axiological, contextual and competence-based approaches. The article describes a pedagogical model of the formation of a health-preserving position of students of a medical university, which includes four interrelated blocks: methodological, substantive, procedural and diagnostic. The basic pedagogical conditions aimed at the formation of a cognitive personality in the process of mastering future professional activities are presented. We have identified three levels of formation of the health-preserving position of students: reproductive, productive, creative. In the course of the research, we came to the conclusion that the integrated technology is an open self-organizing system complex, contributing to the effective formation of the health-preserving position of students, which is an integral learning system that combines theoretical and practical aspects with the use of various forms and methods. The stages of the formation of the student's health-preserving position were determined.

Ecosociocentrism: The Earth First Paradigm for Environmental Sustainability and Sustainable Development

Environmental destruction and degradation that have occurred on planet Earth can be attributed largely to the current neo-liberal economic development paradigm, that considers Nature as simply the resource to be extracted and processed for human consumption and material growth. This paradigm does not consider the intrinsic values in Nature, including the values of life support-services, and goods of the natural ecosystem in the economic valuation system, and therefore, maintaining a healthy, productive, and resilient natural ecosystem becomes simply outside its analytical framework. The most important question that needs to be embedded into any development model is the question of values. If the assumptions of the current economic development model are not restructured and the ecological facts and values are not integrated into economic development model, humanity will inevitably face existential crisis on planet Earth. The scientific epistemology that embodies ecological principle of diversity, ecosystem resilience, interconnectedness, self-organizing complexity, and life sustaining environmental services provides the basis for building social and environmental sustainability. This necessitates the need for the integration of environmental ethics into development framework that can provide the guiding principle for human behavioral conduct. It is argued here that there is a need for a pragmatic environmental ethical paradigm that can integrate both the instrumental and intrinsic values in Nature and promote sustainable development that can lay the foundation for eco-civilization. Recognizing our fundamental interconnectedness with other life forms, self-organizing complexity of the living system and the interdependent nature of our existence, it behooves that development be pursued with a pragmatic environmental ethics that recognizes both the instrumental and intrinsic values in sociosphere (society) and ecosphere (nature). Ecosociocentrism, the proposed ethical framework, recognizes instrumental and intrinsic values in ecosphere and sociosphere. Ecosociocentrism envisages to integrate these values prevalent in ecosphere and sociosphere. Ecosociocentrism claims to provide a pragmatic environmental and development ethical framework for human behavioral conduct to live sustainably in good stewardship with Planet Earth, thus, paving the way to a new era of ecocivilization.

The impact of sources and sinks on the dynamics of homogeneous and heterogeneous boolean networks

Random Boolean networks, originally introduced as simplified models for the genetic regulatory networks, are abstract models widely applied for the study of the dynamical behaviors of self-organizing complex systems. In these networks, connectivity and the bias of the Boolean functions are the most important factors that can determine the behavioral regime of the systems. On the other hand, it has been found that topology and some structural elements of the networks such as the reciprocity, self-loops and source nodes, can have relevant effects on the dynamical properties of critical Boolean networks. In this paper, we study the impact of source and sink nodes on the dynamics of homogeneous and heterogeneous Boolean networks. Our research shows that an increase of the source nodes causes an exponentially growing of the different behaviors that the system can exhibit regardless of the network topology, while the amount of order seems to undergo modifications depending on the topology of the system. Indeed, with the increase of the source nodes the orderliness of the heterogeneous networks also increases, whereas it diminishes in the homogeneous ones. On the other hand, although the sink nodes seem not to have effects on the dynamic of the homogeneous networks, for the heterogeneous ones we have found that an increase of the sinks gives rise to an increasing of the order, although the different potential behaviors of the system remains approximately the same.

Frustrated self-assembly of non-Euclidean crystals of nanoparticles

Self-organized complex structures in nature, e.g., viral capsids, hierarchical biopolymers, and bacterial flagella, offer efficiency, adaptability, robustness, and multi-functionality. Can we program the self-assembly of three-dimensional (3D) complex structures using simple building blocks, and reach similar or higher level of sophistication in engineered materials? Here we present an analytic theory for the self-assembly of polyhedral nanoparticles (NPs) based on their crystal structures in non-Euclidean space. We show that the unavoidable geometrical frustration of these particle shapes, combined with competing attractive and repulsive interparticle interactions, lead to controllable self-assembly of structures of complex order. Applying this theory to tetrahedral NPs, we find high-yield and enantiopure self-assembly of helicoidal ribbons, exhibiting qualitative agreement with experimental observations. We expect that this theory will offer a general framework for the self-assembly of simple polyhedral building blocks into rich complex morphologies with new material capabilities such as tunable optical activity, essential for multiple emerging technologies.