Control-oriented Modeling of Bend Propagation in an Octopus Arm

Bend propagation in an octopus arm refers to a stereotypical maneuver whereby an octopus pushes a bend (localized region of large curvature) from the base to the tip of the arm. Bend propagation arises from the complex interplay between mechanics of the flexible arm, forces generated by internal muscles, and environmental effects (buoyancy and drag) from of the surrounding fluid. In part due to this complexity, much of prior modeling and analysis work has relied on the use of high dimensional computational models. The contribution of this paper is to present a control-oriented reduced order model based upon a novel parametrization of the curvature of the octopus arm. The parametrization is motivated by the experimental results. The reduced order model is related to and derived from a computational model which is also presented. The results from the two sets of models are compared using numerical simulations which is shown to lead to useful qualitative insights into bend propagation. A comparison between the reduced order model and experimental data is also reported

A Sensory Feedback Control Law for Octopus Arm Movements

The main contribution of this paper is a novel sensory feedback control law for an octopus arm. The control law is inspired by, and helps integrate, several observations made by biologists. The proposed control law is distinct from prior work which has mainly focused on open-loop control strategies. Several analytical results are described including characterization of the equilibrium and its stability analysis. Numerical simulations demonstrate life-like motion of the soft octopus arm, qualitatively matching behavioral experiments. Quantitative comparison with bend propagation experiments helps provide the first explanation of such canonical motion using a sensory feedback control law. Several remarks are included that help draw parallels with natural pursuit strategies such as motion camouflage or classical pursuit

Formation of the communicative culture of preschoolers using game activity

The study examines the most significant problems associated with the formation of the communicative culture of preschool children. The main attention is paid to gaming technologies that have a high level of pedagogical efficiency. The reasons for the emergence of problems in the communicative interactions of preschoolers are analyzed; the theoretical foundations in the organization of research aimed at creating a play space that forms the communicative culture of preschool children are proposed. Organizational and pedagogical conditions for the development of the communication skills of preschoolers are highlighted, among which are game technologies that use the capabilities of theatrical art, which can become the basis for the functional development of a preschooler’s personality and their ability to fully communicate with others. On the other hand, the very communicative culture of preschool children is assessed as a mechanism of their socialization and inculturation. The study provides a typology of gaming technologies that are relevant for the development of individual communication skills and the general personal development of children of this age. The study may be of interest to a wide range of specialists in the field of preschool pedagogy, psychology, and children’s art.

Controlling a CyberOctopus Soft Arm with Muscle-like Actuation

This paper presents an application of the energy shaping methodology to control a flexible, elastic Cosserat rod model of a single octopus arm. The novel contributions of this work are two-fold: (i) a control-oriented modeling of the anatomically realistic internal muscular architecture of an octopus arm; and (ii) the integration of these muscle models into the energy shaping control methodology. The control-oriented modeling takes inspiration in equal parts from theories of nonlinear elasticity and energy shaping control. By introducing a stored energy function for muscles, the difficulties associated with explicitly solving the matching conditions of the energy shaping methodology are avoided. The overall control design problem is posed as a bilevel optimization problem. Its solution is obtained through iterative algorithms. The methodology is numerically implemented and demonstrated in a full-scale dynamic simulation environment Elastica. Two bio-inspired numerical experiments involving the control of octopus arms are reported

Energy Shaping Control of a CyberOctopus Soft Arm

This paper entails application of the energy shaping methodology to control a flexible, elastic Cosserat rod model. Recent interest in such continuum models stems from applications in soft robotics, and from the growing recognition of the role of mechanics and embodiment in biological control strategies: octopuses are often regarded as iconic examples of this interplay. Here, the dynamics of the Cosserat rod, modeling a single octopus arm, are treated as a Hamiltonian system and the internal muscle actuators are modeled as distributed forces and couples. The proposed energy shaping control design procedure involves two steps: (1) a potential energy is designed such that its minimizer is the desired equilibrium configuration; (2) an energy shaping control law is implemented to reach the desired equilibrium. By interpreting the controlled Hamiltonian as a Lyapunov function, asymptotic stability of the equilibrium configuration is deduced. The energy shaping control law is shown to require only the deformations of the equilibrium configuration. A forward-backward algorithm is proposed to compute these deformations in an online iterative manner. The overall control design methodology is implemented and demonstrated in a dynamic simulation environment. Results of several bio-inspired numerical experiments involving the control of octopus arms are reported

Determinants of COVID-19 vaccine acceptance in a high infection-rate country: a cross-sectional study in Russia

Background: COVID-19 vaccine development is proceeding at an unprecedented pace. Once COVID-19 vaccines become widely available, it will be necessary to maximize public vaccine acceptance and coverage.Objective: This research aimed to analyze the predictors of COVID-19 vaccine acceptance in Russia.Methods: A cross-sectional online survey was conducted among Russian adults from September 26th to November 9th, 2020. Predictors of the intent to take up COVID-19 vaccination were explored using logistic regression.Results: Out of 876 participants, 365 (41.7%) would be willing to receive the vaccine if it became available. Acceptance increased for a vaccine with verified safety and effectiveness (63.2%). Intention to receive the COVID-19 vaccine was relatively higher among males (aOR=2.37, 95% CI 1.41-4.00), people with lower monthly income (aOR=2.94, 95%CI 1.32-6.57), and with positive trust in the healthcare system (aOR=2.73, 95% CI 1.76-4.24). The Russian people were more likely to accept the COVID-19 vaccine if they believed that the vaccine reduces the risk of virus infection (aOR=8.80, 95%CI 5.21-14.87) or relieves the complications of the disease (aOR=10.46, 95%CI 6.09-17.96). Other barriers such as being unconcerned about side-effects (aOR=1.65, 95%CI 1.03-2.65) and the effectiveness and safety of the vaccination (aOR=2.55, 95%CI 1.60-4.08), also affected acceptance.Conclusions: The study showed the usefulness of the health belief model constructs in understanding the COVID-19 vaccination acceptance rate in the Russian population. This rate was influenced by sociodemographic and health-related characteristics, and health beliefs. These findings might help guide future efforts for policymakers and stakeholders to improve vaccination rates by enhancing trust in the healthcare system

Simple Aesthetic Sense and Addiction Emerge in Neural Relations of Cost-Benefit Decision in Foraging

Abstract A rudimentary aesthetic sense is found in the stimulus valuations and cost-benefit decisions made by primitive generalist foragers. These are based on factors governing personal economic decisions: incentive, appetite, and learning. We find that the addictive process is an extreme expression of aesthetic dynamics. An interactive, agent-based model, ASIMOV, reproduces a simple aesthetic sense from known neural relations of cost-benefit decision in foraging. In the presence of very high reward, an addiction-like process emerges. A drug-like prey provides extreme reward with no nutritive value, initiating high selectivity and prolonged cravings for drug through reward learning. Varying reward experience, caused by homeostatic changes in the neural circuitry of reward, further establishes the course of addiction, consisting of desensitization, withdrawal, resensitization, and associated changes in nutritional choice and pain sensitivity. These observations are consistent with the early evolution of addiction mechanisms in simple generalist foragers as an aesthetic sense for evaluating prey. ASIMOV is accessible to inspection, modification, and experiment, is adaptable as an educational tool, and provides insight on the possible coevolutionary origins of aesthetics and the addiction process

A peripheral subepithelial network for chemotactile processing in the predatory sea slug Pleurobranchaea californica.

Many soft-bodied animals have extensive peripheral nervous systems (PNS) with significant sensory roles. One such, the sea slug Pleurobranchaea californica, uses PNS computations in its chemotactile oral veil (OV) in prey tracking, averaging olfactory stimuli across the OV to target likely source direction, or "stimulus place". This suggests a peripheral subepithelial network (SeN) interconnecting sensory sites to compute the directional average. We pursued anatomy and connectivity of previously described ciliated putative sensory cells on OV papillae. Scanning electron microscopy (SEM) confirmed paddle-shaped cilia in clusters. Anti-tubulin and phalloidin staining showed connections to branching nervelets and muscle fibers for contraction and expansion of papillae. Ciliary cell processes could not be traced into nerves, consistent with sensory transmission to CNS via secondary afferents. Anti-tyrosine hydroxylase-stained ciliated cells in clusters and revealed an at least partially dopaminergic subepithelial network interconnecting clusters near and distant, connections consistent with PNS averaging of multiple stimulated loci. Other, unidentified, SeN neurotransmitters are likely. Confirming chemotactile functions, perfusible suction electrodes recorded ciliary spiking excited by both mechanical and appetitive chemical stimuli. Stimuli induced sensory nerve spiking like that encoding stimulus place. Sensory nerve spikes and cilia cluster spikes were not identifiable as generated by the same neurons. Ciliary clusters likely drive the sensory nerve spikes via SeN, mediating appetitive and stimulus place codes to CNS. These observations may facilitate future analyses of the PNS in odor discrimination and memory, and also suggest such SeNs as potential evolutionary precursors of CNS place-coding circuitry in the segmented, skeletonized protostomes and deuterostomes

Formation of the communicative culture of preschoolers using game activity

The study examines the most significant problems associated with the formation of the communicative culture of preschool children. The main attention is paid to gaming technologies that have a high level of pedagogical efficiency. The reasons for the emergence of problems in the communicative interactions of preschoolers are analyzed; the theoretical foundations in the organization of research aimed at creating a play space that forms the communicative culture of preschool children are proposed. Organizational and pedagogical conditions for the development of the communication skills of preschoolers are highlighted, among which are game technologies that use the capabilities of theatrical art, which can become the basis for the functional development of a preschooler’s personality and their ability to fully communicate with others. On the other hand, the very communicative culture of preschool children is assessed as a mechanism of their socialization and inculturation. The study provides a typology of gaming technologies that are relevant for the development of individual communication skills and the general personal development of children of this age. The study may be of interest to a wide range of specialists in the field of preschool pedagogy, psychology, and children’s art. El estudio examina los problemas más importantes asociados con la formación de la cultura comunicativa de los niños en edad preescolar. La atención principal se presta a las tecnologías de juego que tienen un alto nivel de eficiencia pedagógica. Se analizan las razones del surgimiento de problemas en las interacciones comunicativas de los preescolares; Se proponen los fundamentos teóricos en la organización de la investigación orientada a la creación de un espacio lúdico que forme la cultura comunicativa de los niños en edad preescolar. Se destacan las condiciones organizativas y pedagógicas para el desarrollo de las habilidades comunicativas de los preescolares, entre las que se encuentran las tecnologías de juego que utilizan las capacidades del arte teatral, que pueden convertirse en la base para el desarrollo funcional de la personalidad de un preescolar y su capacidad para comunicarse plenamente con los demás. . Por otro lado, se valora la propia cultura comunicativa de los niños en edad preescolar como mecanismo de su socialización e inculturación. El estudio proporciona una tipología de tecnologías de juego que son relevantes para el desarrollo de las habilidades de comunicación individual y el desarrollo personal general de los niños de esta edad. El estudio puede ser de interés para una amplia gama de especialistas en el campo de la pedagogía preescolar, la psicología y el arte infantil