A Distributed Epigenetic Shape Formation and Regeneration Algorithm for a Swarm of Robots

Living cells exhibit both growth and regeneration of body tissues. Epigenetic Tracking (ET), models this growth and regenerative qualities of living cells and has been used to generate complex 2D and 3D shapes. In this paper, we present an ET based algorithm that aids a swarm of identically-programmed robots to form arbitrary shapes and regenerate them when cut. The algorithm works in a distributed manner using only local interactions and computations without any central control and aids the robots to form the shape in a triangular lattice structure. In case of damage or splitting of the shape, it helps each set of the remaining robots to regenerate and position themselves to build scaled down versions of the original shape. The paper presents the shapes formed and regenerated by the algorithm using the Kilombo simulator.Comment: 8 pages, 9 figures, GECCO-18 conferenc

Sting, Carry and Stock: How Corpse Availability Can Regulate de-Centralized Task Allocation in a Ponerine Ant Colony

We develop a model to produce plausible patterns of task partitioning in the ponerine ant Ectatomma ruidum based on the availability of living prey and prey corpses. The model is based on the organizational capabilities of a common stomach through which the colony utilizes the availability of a natural (food) substance as a major communication channel to regulate the income and expenditure of the very same substance. This communication channel has also a central role in regulating task partitioning of collective hunting behavior in a supply&demand-driven manner. Our model shows that task partitioning of the collective hunting behavior in E. ruidum can be explained by regulation due to a common stomach system. The saturation of the common stomach provides accessible information to individual ants so that they can adjust their hunting behavior accordingly by engaging in or by abandoning from stinging or transporting tasks. The common stomach is able to establish and to keep stabilized an effective mix of workforce to exploit the prey population and to transport food into the nest. This system is also able to react to external perturbations in a de-centralized homeostatic way, such as to changes in the prey density or to accumulation of food in the nest. In case of stable conditions the system develops towards an equilibrium concerning colony size and prey density. Our model shows that organization of work through a common stomach system can allow Ectatomma ruidum to collectively forage for food in a robust, reactive and reliable way. The model is compared to previously published models that followed a different modeling approach. Based on our model analysis we also suggest a series of experiments for which our model gives plausible predictions. These predictions are used to formulate a set of testable hypotheses that should be investigated empirically in future experimentation

Integral Feedback Control Is at the Core of Task Allocation and Resilience of Insect Societies

Homeostatic self-regulation is a fundamental aspect of open dissipative systems. Integral feedback has been found to be important for homeostatic control on both the cellular and molecular levels of biological organization and in engineered systems. Analyzing the task allocation mechanisms of three insect societies, we identified a model of integral control residing at colony level. We characterized a general functional core mechanism, called the “common stomach,” where a crucial shared substance for colony function self-regulates its own quantity via reallocating the colony’s workforce, which collects and uses this substance. The central component in a redundant feedback network is the saturation level of this substance in the colony. An interaction network of positive and negative feedback loops ensures the homeostatic state of this substance and the workforce involved in processing this substance. Extensive sensitivity and stability analyses of the core model revealed that the system is very resilient against perturbations and compensates for specific types of stress that real colonies face in their ecosystems. The core regulation system is highly scalable, and due to its buffer function, it can filter noise and find a new equilibrium quickly after environmental (supply) or colony-state (demand) changes. The common stomach regulation system is an example of convergent evolution among the three different societies, and we predict that similar integral control regulation mechanisms have evolved frequently within natural complex systems

ASSISIbf: A new pathway to examine collective behaviours in honeybees

Dissertação de mestrado em Biologia Celular e Molecular, apresentada ao Departamento de Ciências da Vida da Faculdade de Ciências e Tecnologia da Universidade de Coimbra.Diabetes mellitus (DM) is a degenerative disease representing one of the greatest concerns to modern global health, and worryingly with its incidence increasing worldwide at epidemic rates. DM is associated with the emergence of a variety of clinical complications, including reproductive dysfunction. Given the extension and multifactorial nature of diabetes-induced physiological changes, it remains unclear what are the mechanisms that may contribute for the reproductive dysfunction described in male diabetic patients. Considering that hyperglycemia has been described as a major effector of the disease pathophysiology, two different in vitro approaches were used to address the isolated effect of high glucose conditions on sperm function and spermatogenesis, thus avoiding other in vivo confounding players. A complete and integrated analysis, through a diversity of important indicators of spermatozoa functionality (motility, viability, capacitation status, acrosomal integrity, mitochondrial superoxide production and mitochondrial membrane potential) suggests that high glucose concentrations does not seem to directly affect spermatozoa, at least in vitro. Organ culture experiments, mimicking the spermatogenic process, determined that high glucose levels increase Sertoli cell number while decreasing tubular luminal area, therefore suggesting an impairment of this somatic cell type with hub importance in spermatogenic control. Taken together, this study suggests that high glucose levels per se seems to influence the male reproductive system only at the spermatogenesis level, stressing the importance of other factors involved in the disease.A Diabetes mellitus (DM) é uma doença degenerativa cuja incidência está a aumentar de forma galopante, sendo actualmente considerada um grave problema de saúde pública. A DM está ainda associada ao surgimento de uma grande variedade de complicações clínicas afectando todos os sistemas de órgãos, não sendo o sistema reprodutor masculino uma excepção. Dada a extensão e natureza multifatorial das alterações fisiológicas induzidas pela DM, permanecem ainda por esclarecer quais os mecanismos responsáveis pela disfunção reprodutora frequentemente reportada em pacientes diabéticos do sexo masculino, incluindo alterações na espermatogénese ou em vários parâmetros seminais. Considerando que a hiperglicémia tem sido descrita como um dos principais efectores das alterações associadas à DM, no presente projecto, foi estudado, através de duas abordagens in vitro distintas, o efeito isolado da hiperglicémia na função espermática e na progressão do processo espermatogénico. Estes sistemas permitiram assim excluir outros factores envolvidos na doença. Uma análise completa e integrada, realizada através da avaliação de uma grande diversidade de importantes indicadores da funcionalidade espermática (mobilidade, viabilidade, estado de capacitação, integridade acrossomal, produção de superóxido mitocondrial e potencial membranar mitocondrial) sugere que, pelo menos in vitro, elevadas concentrações de glucose não afectam directamente o espermatozóide. Os resultados obtidos com um sistema de cultura de órgãos permitiram verificar que elevados níveis de glucose levaram a um aumento do número de células de Sertoli e a uma diminuição da área luminal tubular. Estes resultados sugerem, portanto, uma disfunção neste tipo de células somáticas essenciais para o controlo da espermatogénese. Através deste estudo foi possível verificar e sugerir que a disfunção reprodutora de pacientes do sexo masculino parece não resultar apenas da influência da glucose, apesar de terem sido detectadas alterações ao nível da espermatogénese, sublinhando a importância da natureza multifactorial da doença

Lifeforms potentially useful for automated underwater monitoring systems

Biohybrids combine artificial robotic elements with living organisms. These novel technologies allow for obtaining useful data on the environment by implementing organisms as “living sensors”. Natural water resources are under serious ecological threat and there is always a need for new, more efficient methods for aquatic monitoring. Project Robocoenosis introduces the use of biohybrid entities as low-cost and long-term environmental monitoring devices. This will be done by combining lifeforms with technical parts which will be powered with the use of MFCs. This concept will allow for a more well-rounded data collection and provide an insight into the water body with minimal human impact