Self-repair ability of evolved self-assembling systems in cellular automata

Self-repairing systems are those that are able to reconfigure themselves following disruptions to bring them back into a defined normal state. In this paper we explore the self-repair ability of some cellular automata-like systems, which differ from classical cellular automata by the introduction of a local diffusion process inspired by chemical signalling processes in biological development. The update rules in these systems are evolved using genetic programming to self-assemble towards a target pattern. In particular, we demonstrate that once the update rules have been evolved for self-assembly, many of those update rules also provide a self-repair ability without any additional evolutionary process aimed specifically at self-repair

The molecular aspects of biological development

Conference on molecular aspects of biological developmen

Turing Patterns and Biological Explanation

Turing patterns are a class of minimal mathematical models that have been used to discover and conceptualize certain abstract features of early biological development. This paper examines a range of these minimal models in order to articulate and elaborate a philosophical analysis of their epistemic uses. It is argued that minimal mathematical models aid in structuring the epistemic practices of biology by providing precise descriptions of the quantitative relations between various features of the complex systems, generating novel predictions that can be compared with experimental data, promoting theory exploration, and acting as constitutive parts of empirically adequate explanations of naturally occurring phenomena, such as biological pattern formation. Focusing on the roles that minimal model explanations play in science motivates the adoption of a broader diachronic view of scientific explanation

Regulatory feedback on receptor and non-receptor synthesis for robust signaling.

Elaborate regulatory feedback processes are thought to make biological development robust, that is, resistant to changes induced by genetic or environmental perturbations. How this might be done is still not completely understood. Previous numerical simulations on reaction-diffusion models of Dpp gradients in Drosophila wing imaginal disc have showed that feedback (of the Hill function type) on (signaling) receptors and/or non-(signaling) receptors are of limited effectiveness in promoting robustness. Spatial nonuniformity of the feedback processes has also been shown theoretically to lead to serious shape distortion and a principal cause for ineffectiveness. Through mathematical modeling and analysis, the present article shows that spatially uniform nonlocal feedback mechanisms typically modify gradient shape through a shape parameter (that does not change with location). This in turn enables us to uncover new multi-feedback instrument for effective promotion of robust signaling gradients

Instantaneous cell migration velocity may be ill-defined

Cell crawling is critical to biological development, homeostasis and disease. In many cases, cell trajectories are quasi-random-walk. In vitro assays on flat surfaces often described such quasi-random-walk cell trajectories as approximations to a solution of a Langevin process. However, experiments show quasi-diffusive behavior at small timescales, indicating that instantaneous velocity and velocity autocorrelations are not well-defined. We propose to characterize mean-squared cell displacement using a modified F\"urth equation with three temporal and spatial regimes: short- and long-time/range diffusion and intermediate time/range ballistic motion. This analysis collapses mean-squared displacements of previously published experimental data onto a single-parameter family of curves, allowing direct comparison between movement in different cell types, and between experiments and numerical simulations. Our method also show that robust cell-motility quantification requires an experiment with a maximum interval between images of a few percent of the cell-motion persistence time or less, and a duration of a few orders-of-magnitude longer than the cell-motion persistence time or more.Comment: 5 pages, plus Supplemental materia

Development of Morphogen Gradient: The Role of Dimension and Discreteness

The fundamental processes of biological development are governed by multiple signaling molecules that create non-uniform concentration profiles known as morphogen gradients. It is widely believed that the establishment of morphogen gradients is a result of complex processes that involve diffusion and degradation of locally produced signaling molecules. We developed a multi-dimensional discrete-state stochastic approach for investigating the corresponding reaction-diffusion models. It provided a full analytical description for stationary profiles and for important dynamic properties such as local accumulation times, variances and mean first-passage times. The role of discreteness in developing of morphogen gradients is analyzed by comparing with available continuum descriptions. It is found that the continuum models prediction about multiple time scales near the source region in two-dimensional and three-dimensional systems is not supported in our analysis. Using ideas that view the degradation process as an effective potential, the effect of dimensionality on establishment of morphogen gradients is also discussed. In addition, we investigated how these reaction-diffusion processes are modified with changing the size of the source region

HOW DOES SCHIZOPHRENIA OCCUR AND CAN DELUSIONS BE PROTECTIVE TO THE PERSON? A BIRD’S EYE VIEW ATTEMPTING TO INTEGRATE THE NEUROBIOLOGY AND PSYCHOLOGY OF SCHIZOPHRENIA

This short paper is an attempt to integrate what we know about the biological development of schizophrenia. It attempts to integrate Neurodevelomental, Dopamine, Glutamate, Salience and Psychological theories of the development of schizophrenia into a unitary whole, and thus to illustrate how these theories relate together. It is a summary of a much larger work, presently in preparation, done for the purposes of the present coference. It attempts to describe the biological development of schizophrenia, and thence the delusions and hallucinations which play a part in it symptomatically

Medical Supervision of Young Female Athletes Training in Complex Coordinational Sports

This article proposes simple medical criteria that can be used by trainers and others for effective medical supervision of young female athletes. METHODS: The cross-sectional, age-stratified study compared girls 10-17 years of age involved in intensive training in gymnastic floor exercises, trampoline, or badminton. Each sport and/or control group was represented by 40-45 girls. Data included medical history, morphometric variables and observation of biological development. RESULTS: Gymnasts started training earliest (approximately 5-years-old) and trained most intensely (18-20 h/wk), followed by trampolinists and then badmintonists. Height, weight, body mass index, and % body fat were reduced in athletes, with gymnasts showing the greatest reduction. Athletes showed higher ratios of leg length to height and shoulder width/hip width, and smaller pelvic size compared to height. The average age of menarche of gymnasts was 13.8 (1.6 year later than controls). Delays of biological development of more than 2 years were common in athletes, and some gymnasts showed more than a 4-year delay. These delays were related to morphometric indicators of hormonal imbalance and to low body fat. Gymnasts had more childhood diseases, with an infection index of 2.8 compared to 1.1 for the control group, and had a higher level of chronic ENT problems. CONCLUSIONS: Trainers need to protect the health of athletes. During the course of training, anamneses, delayed menarche and other signs of delayed biological development must be monitored. Morphometric measures and indicators of biological development are proposed to provide simple criteria important in protecting the athletes\u27 health