Network Dynamics, Synchronization, and Self-Propelled Particles in Chemical Systems

Neural networks are a class of biological networks of great importance. They are a key component of the central nervous system that coordinates body functions. The exploration of the detailed mechanism of biological neural networks remains extremely active. Inspired by the structure of biological neural networks, artificial neural networks have been designed to solve a variety of problems in pattern recognition, prediction, optimization and control. However, few studies have been reported that explore the dynamics of biological neural networks using chemical systems. As part of this thesis, an experimentally trainable network based on the photosensitive Belousov-Zhabotinsky reaction is developed, where the individual node is a catalyst loaded micro-particle. The interactions between nodes in the network are created by arranging links with different weights, similar to the excitable and inhibitory synapses in biological neural networks. The distribution of the weights of the excitable links has been studied. The results indicate that a stable distribution of the weights is exhibited.;Synchronization in coupled nonlinear oscillators is a remarkable and ubiquitous phenomenon in nature. Application of periodic global feedback to oscillators allows the creation of new kinds of wave patterns with the coexistence of stable phase states. In experiments with the photosensitive BZ reaction, periodic global feedback is implemented by varying the illumination intensity. In a 1:1 frequency-locked entrainment, 2pi phase fronts called phase kinks have been observed in the photosensitive BZ reaction. Generally, a phase kink represents the existence of stable phase differences, propagating as an analog of traveling waves in 2D excitable media. By modifying the conditions of local forcing, the experiments show that a phase kink can be trapped to form a closed pattern.;Self-propulsion is an essential feature of many living systems. There are numerous realizations of self-propelled particles in biological systems, such as the bacteria Listeria monocytogenes in cells. Such biological phenomena inspire the creation of artificial self-propelled particles. Recently, nonbiological micro- to nanoscale particles, that convert chemical energy into translational motion, have been investigated. Studies show that Pt-coated polystyrene particles, coated on one hemisphere with Pt, exhibit self-propulsion in dilute H2O2 solutions. Here, we experimentally study the dynamical behavior of silica particles that are asymmetrically coated with Pt in H2O2 solutions, similar to Pt-coated polystyrene particles. The focus of our study is on the particle orientation with respect to the direction of motion. This is investigated using velocity autocorrelation and propulsion direction analyses

Modelling the dynamic flight behaviour of birds in different frames of reference

In this thesis I consider two aspects – energetics and guidance – of two dynamic flight behaviours performed by birds – dynamic soaring and prey pursuit. Uniting the thesis is the collection and modelling of bird trajectory data in different frames of reference to make inferences on dynamic flight behaviour. In particular, I collect data in a camera-fixed reference frame to model the dynamic soaring flight trajectories of Manx shearwater in an aerodynamic reference frame, whereas I model the attack trajectories of Harris’ hawks in both an inertial and a background frame of reference using data collected in an Earth-fixed frame of reference. The output of my investigation into the energetics of dynamic soaring is the first empirical demonstration of dynamic soaring outside the albatrosses, the formulation of a new metric for identifying and quantifying dynamic soaring, and the demonstration that the large-scale distribution of the Manx shearwater is affected by their dynamic soaring behaviour. The output of my investigation into the guidance of prey pursuit is the finding that Harris’ hawk attack trajectories are well modelled by the proportional navigation (PN) guidance law commonly used by homing missiles. However, I also show that a guidance law that can be mechanised using only visual information – rather than the inertial and visual information required by PN – also successfully fits attack trajectory data. Finally, I propose a method for analysing eye-in-head movements during dynamic flight in birds, and I find that Harris’ hawks limit eye-in-head movement during terminal pursuit, a necessary condition to implement PN guidance. In being reflective about the reference frames in which I model bird behaviour and, in cases, by modelling the same data in different reference frames, I expose the utility of the reference frame concept in analysing biological systems

Development of techniques for time-lapse imaging of the dynamics of glial-axonal interactions in the central nervous system

Background: Myelination is an exquisite and dynamic example of heterologous cell-cell interaction, which consists of the concentric wrapping of multiple layers of oligodendrocyte membrane around neuronal axons. Understanding the mechanism by which oligodendrocytes ensheath axons may bring us closer to designing strategies to promote remyelination in demyelinating diseases. The main aim of this study was to follow glial-axonal interactions over time both in vitro and ex vivo to visualise the various stages of myelination. Methodology/Principal findings: Two approaches have been taken to follow myelination over time i) time-lapse imaging of mixed CNS myelinating cultures generated from mouse spinal cord to which exogenous GFP-labelled murine cells were added, and ii) ex vivo imaging of the spinal cord of shiverer (Mbp mutant) mice, transplanted with GFP-labelled murine neurospheres. The data demonstrate that oligodendrocyte-axonal interactions are dynamic events with continuous retraction and extension of oligodendroglial processes. Using cytoplasmic and membrane-GFP labelled cells to examine different components of the myelin-like sheath, evidence from time-lapse fluorescence microscopy and confocal microscopy suggest that the oligodendrocytes’ cytoplasm-filled processes initially spiral around the axon in a corkscrew-like manner. This is followed subsequently by focal expansion of the corkscrew process to form short cuffs which then extend longitudinally along the axons. From this model it is predicted that these spiral cuffs must extend over each other first before extending to form internodes of myelin. Conclusion: These experiments show the feasibility of visualising the dynamics of glial-axonal interaction during myelination over time. Moreover, these approaches complement each other with the in vitro approach allowing visualisation of an entire internodal length of myelin and the ex vivo approach validating the in vitro data

Biometric Systems

Because of the accelerating progress in biometrics research and the latest nation-state threats to security, this book's publication is not only timely but also much needed. This volume contains seventeen peer-reviewed chapters reporting the state of the art in biometrics research: security issues, signature verification, fingerprint identification, wrist vascular biometrics, ear detection, face detection and identification (including a new survey of face recognition), person re-identification, electrocardiogram (ECT) recognition, and several multi-modal systems. This book will be a valuable resource for graduate students, engineers, and researchers interested in understanding and investigating this important field of study

21st International Congress of Aesthetics, Possible Worlds of Contemporary Aesthetics Aesthetics Between History, Geography and Media, Book of Abstracts

The Faculty of Architecture, University of Belgrade and the Society for Aesthetics of Architecture and Visual Arts of Serbia (DEAVUS) are proud to be able to organize the 21st ICA Congress on “Possible Worlds of Contemporary Aesthetics: Aesthetics Between History, Geography and Media”. We are proud to announce that we received over 500 submissions from 56 countries, which makes this Congress the greatest gathering of aestheticians in this region in the last 40 years. The ICA 2019 Belgrade aims to map out contemporary aesthetics practices in a vivid dialogue of aestheticians, philosophers, art theorists, architecture theorists, culture theorists, media theorists, artists, media entrepreneurs, architects, cultural activists and researchers in the fields of humanities and social sciences. More precisely, the goal is to map the possible worlds of contemporary aesthetics in Europe, Asia, North and South America, Africa and Australia. The idea is to show, interpret and map the unity and diverseness in aesthetic thought, expression, research, and philosophies on our shared planet. Our goal is to promote a dialogue concerning aesthetics in those parts of the world that have not been involved with the work of the International Association for Aesthetics to this day. Global dialogue, understanding and cooperation are what we aim to achieve. That said, the 21st ICA is the first Congress to highlight the aesthetic issues of marginalised regions that have not been fully involved in the work of the IAA. This will be accomplished, among others, via thematic round tables discussing contemporary aesthetics in East Africa and South America. Today, aesthetics is recognized as an important philosophical, theoretical and even scientific discipline that aims at interpreting the complexity of phenomena in our contemporary world. People rather talk about possible worlds or possible aesthetic regimes rather than a unique and consistent philosophical, scientific or theoretical discipline

Proceedings of the 21st International Congress of Aesthetics, Possible Worlds of Contemporary Aesthetics Aesthetics Between History, Geography and Media

The Faculty of Architecture, University of Belgrade and the Society for Aesthetics of Architecture and Visual Arts of Serbia (DEAVUS) are proud to be able to organize the 21st ICA Congress on “Possible Worlds of Contemporary Aesthetics: Aesthetics Between History, Geography and Media”. We are proud to announce that we received over 500 submissions from 56 countries, which makes this Congress the greatest gathering of aestheticians in this region in the last 40 years. The ICA 2019 Belgrade aims to map out contemporary aesthetics practices in a vivid dialogue of aestheticians, philosophers, art theorists, architecture theorists, culture theorists, media theorists, artists, media entrepreneurs, architects, cultural activists and researchers in the fields of humanities and social sciences. More precisely, the goal is to map the possible worlds of contemporary aesthetics in Europe, Asia, North and South America, Africa and Australia. The idea is to show, interpret and map the unity and diverseness in aesthetic thought, expression, research, and philosophies on our shared planet. Our goal is to promote a dialogue concerning aesthetics in those parts of the world that have not been involved with the work of the International Association for Aesthetics to this day. Global dialogue, understanding and cooperation are what we aim to achieve. That said, the 21st ICA is the first Congress to highlight the aesthetic issues of marginalised regions that have not been fully involved in the work of the IAA. This will be accomplished, among others, via thematic round tables discussing contemporary aesthetics in East Africa and South America. Today, aesthetics is recognized as an important philosophical, theoretical and even scientific discipline that aims at interpreting the complexity of phenomena in our contemporary world. People rather talk about possible worlds or possible aesthetic regimes rather than a unique and consistent philosophical, scientific or theoretical discipline

Proceedings of the 23rd International Congress of Byzantine Studies : Round Tables

Following the 23rd International Congress of Byzantine Studies, the Organizing Committee decided to produce an online publication of Proceedings from the Round Tables. According to the official title of the congress, Byzantium - a World of Changes, AIEB together with the Organizing Committee, have decided to implement some changes to the concept of the Round Tables. The aim of these changes were to encourage discussion at the Round Tables by presenting preliminary papers at the website in advance. The idea was to introduce the topic and papers of the individual Round Tables that would be discussed, first between the participants, and then with the public present. Therefore, the conveners of the Round Tables were asked to create Round Tables with no more than 10 participants. They collected the papers, which were to be no longer than 18,000 characters in one of the official languages of the Congress and without footnotes or endnotes. Conveners provided a general statement on the goal of each roundtable and on the content of the papers. The present volume contains papers from 49 Round Tables carefully selected to cover a wide range of topics, developed over the last five years since the previous Congress. The topics show diversity within fields and subfields, ranging from history to art history, archeology, philosophy, literature, hagiography, and sigillography. The Round Tables displayed current advances in research, scholarly debates, as well as new methodologies and concerns germane to all aspects of international Byzantine studies. The papers presented in this volume were last sent to the congress organizers in the second week of August 2016 and represent the material that was on hand at that time and had been posted on the official website; no post-congress revisions have occurred. We present this volume in hope that it will be an initial step for further development of Round Tables into collections of articles and thematic books compiled and published following the Congress, in collaboration with other interested institutions and editors. With this volume, the organizers signal their appreciation of the efforts of more than 1600 participants who contributed, both to the Round Tables and to the Congress in general