Modelling Learning to Count in Humanoid Robots

In reference to IEEE copyrighted material which is used with permission in this thesis, the IEEE does not endorse any of Plymouth University's products or services. Internal or personal use of this material is permitted. If interested in reprinting/republishing IEEE copyrighted material for advertising or promotional purposes or for creating new collective works for resale or redistribution, please go to http://www.ieee.org/publications_standards/publications/rights/rights_link.html to learn how to obtain a License from RightsLink.This thesis concerns the formulation of novel developmental robotics models of embodied phenomena in number learning. Learning to count is believed to be of paramount importance for the acquisition of the remarkable fluency with which humans are able to manipulate numbers and other abstract concepts derived from them later in life. The ever-increasing amount of evidence for the embodied nature of human mathematical thinking suggests that the investigation of numerical cognition with the use of robotic cognitive models has a high potential of contributing toward the better understanding of the involved mechanisms. This thesis focuses on two particular groups of embodied effects tightly linked with learning to count. The first considered phenomenon is the contribution of the counting gestures to the counting accuracy of young children during the period of their acquisition of the skill. The second phenomenon, which arises over a longer time scale, is the human tendency to internally associate numbers with space that results, among others, in the widely-studied SNARC effect. The PhD research contributes to the knowledge in the subject by formulating novel neuro-robotic cognitive models of these phenomena, and by employing these in two series of simulation experiments. In the context of the counting gestures the simulations provide evidence for the importance of learning the number words prior to learning to count, for the usefulness of the proprioceptive information connected with gestures to improving counting accuracy, and for the significance of the spatial correspondence between the indicative acts and the objects being enumerated. In the context of the model of spatial-numerical associations the simulations demonstrate for the first time that these may arise as a consequence of the consistent spatial biases present when children are learning to count. Finally, based on the experience gathered throughout both modelling experiments, specific guidelines concerning future efforts in the application of robotic modelling in mathematical cognition are formulated.This research has been supported by the EU project RobotDoC (235065) from the FP7 Marie Curie Actions ITN

Comparison of chromosome centromere topology in differentiating cells with myogenic potential.

Chromosome territories (CT's) constitute the critical element of the intranuclear architecture. Position of these compartmentalized structures plays an important role in functioning of entire genome. Present study was to examine whether the centromeres position of chromosomes 4, X and Y can be changed during differentiation from myoblasts to myotubes. Topological analysis of these centromeres was based on two-dimensional fluorescent hybridization in situ (2D-FISH). During differentiation process the majority of X chromosome centromeres analyzed shifted to the peripheral part of a nucleus and similar phenomenon was observed with one of the chromosome 4 centromeres. Completely different tendency was noticed when investigating the location of the chromosome Y centromeres. Centromeres of this chromosome migrated to the centre of a nucleus. The results obtained demonstrated visible changes in chromosome topology along the myogenic stem cells differentiation

In vitro culture of primary human myoblasts by using the dextran microcarriers Cytodex3®

Introduction. Primary cells in vitro culture scale-up is a crucial issue in cell-based tissue and organ regeneration therapy. Reducing costs and space occupied by the cells cultured in vitro has been an important target. Cells cultured in vitro with the use of bioreactor with dextran microcarriers (Cytodex®) have potentially a chance to meet many of the cell therapy requirements. Material and methods. We used collagen-coated carriers (Cytodex3®) and a spinner flask bioreactor to develop environment suitable for human myoblast proliferation. In parallel, standard adherent in vitro culture conditions for myoblasts propagation (T-flask) were conducted. Cell cycle characterization, senescence, myogenic gene ex­pression and cell apoptosis were evaluated in order to find differences between two culture systems under study. Results. The number of cells obtained in bioreactor per 106 of starting cells population was approximately ten times lower in comparison with T-flask culture system. The microcarriers cultured adult myoblasts in compari­son with the regular T-flask culture showed faster and more advanced replicative aging and lower proliferative potential. Moreover, the percentage of the cells that entailed an irreversible cell arrest (G0 phase) was also significantly (p < 0.0001) increased. Conclusions. Our results suggest that population of primary human myoblasts obtained from adult individuals and propagated on dextran microcarriers did not meet the requirements of the regenerative medicine regarding quantity and quality of the cells obtained. Nonetheless, further optimization of the cell scaling up process including both microcarriers and/or bioreactor program is still an important option

Insights into the inner regions of the FU Orionis disc

Context. We investigate small-amplitude light variations in FU Ori occurring in timescales of days and weeks. Aims. We seek to determine the mechanisms that lead to these light changes. Methods. The visual light curve of FU Ori gathered by the MOST satellite continuously for 55 days in the 2013-2014 winter season and simultaneously obtained ground-based multi-colour data were compared with the results from a disc and star light synthesis model. Results. Hotspots on the star are not responsible for the majority of observed light variations. Instead, we found that the long periodic family of 10.5-11.4 d (presumably) quasi-periods showing light variations up to 0.07 mag may arise owing to the rotational revolution of disc inhomogeneities located between 16-20 solar radii. The same distance is obtained by assuming that these light variations arise because of a purely Keplerian revolution of these inhomogeneities for a stellar mass of 0.7 solar mass. The short-periodic (3-1.38 d) small amplitude (0.01 mag) light variations show a clear sign of period shortening, similar to what was discovered in the first MOST observations of FU Ori. Our data indicate that these short-periodic oscillations may arise because of changing visibility of plasma tongues (not included in our model), revolving in the magnetospheric gap and/or likely related hotspots as well. Conclusions. Results obtained for the long-periodic 10-11 d family of light variations appear to be roughly in line with the colour-period relation, which assumes that longer periods are produced by more external and cooler parts of the disc. Coordinated observations in a broad spectral range are still necessary to fully understand the nature of the short-periodic 1-3 d family of light variations and their period changes.Comment: Accepted to A&

Immunohistochemical analysis of ghrelin expression in various types of adrenal tumors

Introduction. Ghrelin, originally isolated from the endocrine cells of the gastric mucosa, is also expressed in many peripheral tissues, including normal adrenals and adrenocortical tumors. It was shown that ghrelin stimulates proliferation and inhibits apoptosis of adrenocortical cells. In the current study, we compared ghrelin expression at the protein level in various adrenal tumors. We analyzed whether immunoreactive ghrelin could be considered as a potential marker for different types of adrenal tumors. Material and methods. Study was carried out on 200 adrenal specimens arranged on microscope slide in tissue microarray format. We performed standardized immunohistochemical reactions with semiquantitative reaction intensity measurements. Results. At the protein level, the expression of ghrelin was significantly reduced in adrenocortical adenocarcinoma in relation to the control group and pheochromocytoma as well as cancer-adjacent normal adrenal tissue. In contrast, a relatively high ghrelin expression was found in pheochromocytoma compared to all analyzed groups, with the exception of cancer-adjacent normal adrenal tissue. Conclusions. The ghrelin expression profile at the protein level may be associated with the type of adrenal tumor. In this context, our results suggest that adrenal immunoreactive ghrelin may be considered as a sensitive and specific marker for differentiating adrenocortical carcinoma from adrenocortical adenoma and pheochromocytoma