Simulating Organogenesis in COMSOL: Tissue Mechanics

During growth, tissue expands and deforms. Given its elastic properties, stresses emerge in an expanding and deforming tissue. Cell rearrangements can dissipate these stresses and numerous experiments confirm the viscoelastic properties of tissues [1]-[4]. On long time scales, as characteristic for many developmental processes, tissue is therefore typically represented as a liquid, viscous material and is then described by the Stokes equation [5]-[7]. On short time scales, however, tissues have mainly elastic properties. In discrete cell-based tissue models, the elastic tissue properties are realized by springs between cell vertices [8], [9]. In this article, we adopt a macroscale perspective of tissue and consider it as homogeneous material. Therefore, we may use the "Structural Mechanics" module in COMSOL Multiphysics in order to model the viscoelastic behavior of tissue. Concretely, we consider two examples: first, we aim at numerically reproducing published [10] analytical results for the sea urchin blastula. Afterwards, we numerically solve a continuum mechanics model for the compression and relaxation experiments presented in [4]

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Biourbanism for a healthy city: biophilia and sustainable urban theories and practices

The paper was given via audio/slides file on 4th September 2012 in the International Convention on Innovations in Engineering and Technology for Sustainable Development, 3-5 September 2012, in Bannari Amman Institute of Technology, Erode District, Tamil Nadu, India. The paper was peer reviewed and accepted in July 2012.Vital elements in urban fabric have been often concealed for reasons of design. Recent theories, such as Biourbanism, suggest that cities risk becoming unstable and deprived of healthy social interactions. Our paper aims at exploring the reasons for which,fractal cities, for example can have beneficial impact on human fitness of body and mind. During the last few decades, modern urban fabric lost some very important elements, only because urban design and planning became stylistic patterns of fancy aerial views to show mainly iconic signature architecture. Biourbanism attempts to reestablish lost values and balance, not only in urban fabric, but also in reinforcing human-oriented design principles to be easily implemented and understood. The Lancet Commission of Healthy Cities provides an analysis of how health outcomes are part of the complexity of urban processes, highlighting the role that urban planning can, and should play in delivering health improvements through processes of reshaping the urban fabric of our cities around the globe. This paper describes how the application of Biourbanism’s principles can improve the quality of the urban environment with reference to both physical transformations of it and psychological impact upon city inhabitants. Therefore, these principles are accomplished to support urban structural sustainability.ADT and School of Technology funds

Soft Rock Studio: Exploring a “Soft Systems” Approach to “Artificial Rock”

This paper discusses a study aimed at shifting disciplinary norms in construction materials. The study, conducted in a graduate level design-build studio, approached precast concrete construction through the lens of “artificial rock”: a composite material that can use cement, sand, aggregate, and reinforcing supplements and alternatives like flax, calcium carbonate, pyrolyzed biomass, soil, alginates, gelatin, and bacteria. Taught as “The Soft Rock Studio”, the course positioned artificial rock within the larger conceptual framework of “soft systems” - adaptive, networked part-to-whole relationships engaged in feedback loops with the environment. The Soft Rock Studio designed and prototyped components and assemblies for an alignment structure – or sky room - for a coastal site. Alignment structures are landscape and architecture constructions that align with the daytime and evening events in the sky: equinoxes, cardinal directions, constellations and solar orientations. The study design integrated empirical making, material testing and computational simulation in an iterative design methodology. The design methodology was tailored for a remote learning context and included the design and distribution of a material kit for at-home experimentation. Integrated with the methodology were process portfolios documenting student research and reflection, including responses to technology and humanities literature. Outcomes discussed in this paper are: material experimentations and iterative design possibilities of two student projects; evidence of student uptake; and reflections on the iterative design methodology. Observations and findings from alignment structure strategies are not included in the scope of this paper

Do management accounting systems influence organizational change or vice-versa? Evidence from a case of constructive research in the Healthcare Sector

The paper aims to analyze the process of change of management accounting system (MAS) as a consequence of changes in the complexity of organizational structure in healthcare. It analyzes the process of change of MAS according with the theoretical frameworks of Habermas (1987) and Laughlin (1991).In this organizational changes are seen as the consequence of the interaction between tangible and intangible elements of the organization and between the organization and the external environment. The process of change was not studied from an external standpoint, but through an active participation and contribution of the researchers in the process of change itself. Using a constructive approach, the researchers were actively involved with the actors of the change in developing the process of change, and in facilitating the overcoming of some cultural gaps and resistance which could arise in professional organization. The paper provides empirical insights of the characteristics of the process of change of MAS in a Heath Care setting with a particular focus on aspects characterizing the process of change itself. Finding suggests the importance of putting high attention in the development of the process of change and underlines how the attention to peculiarities of the organization, in to this phase, could make the MAS able to impact on the behaviours and culture of professionals.Management Accounting Change, Healthcare Accounting, Habermas

The city of future: biourbanism and constructural law

Nowadays dynamic elements in urban fabric are often concealed by the insertion of stylish new architecture; real patterns of social life (‘bios’), have been replaced by rigid geometric grids and compact building blocks. New Urbanism and Biourbanism affirm that cities are now risking to be unstable and deprived of healthy social interactions. As an expansion of older historical urban fabric patterns, harmonious architecture can have a positive impact on the fitness of both human body and mind. Not only Biourbanism attempts to reinstate balance and lost values in the urban fabric, but also reinforces human-oriented design emergences in micro and macro scales. As a multifaceted discipline, it embraces laws of physics, such as Constructal Law and acknowledges its noticeable and unremitting influence to urban human behaviours. Urban life and behaviours are based upon systems of human communication formed by dynamic patterns; we are now talking about negotiating boundaries between human activities, changes in geographic mapping and mainly about sustainable systems to support uninterrupted growth of communities worldwide. Therefore, as a vital shift in architectural education, not only Biourbanism offers the opportunity to explore patterns and linguistics deeply imbedded into the built environment, but also enables scholars and communities to come together and participate actively into fast and innovative urban interventions. Projects developed during educational and professional training aim at reinstating memorable and preferential paths of communication, favouring everyday life rituals of the body and mind. Hence, by following everlasting laws of physics and formulas inherited from nature, architectural forms can be considered as the real innovation in urban design and planning of the City of the Future.Conference presentation funded by Department of Engineering

Transformation in a changing climate: a research agenda

The concept of transformation in relation to climate and other global change is increasingly receiving attention. The concept provides important opportunities to help examine how rapid and fundamental change to address contemporary global challenges can be facilitated. This paper contributes to discussions about transformation by providing a social science, arts and humanities perspective to open up discussion and set out a research agenda about what it means to transform and the dimensions, limitations and possibilities for transformation. Key focal areas include: (1) change theories, (2) knowing whether transformation has occurred or is occurring; (3) knowledge production and use; (4), governance; (5) how dimensions of social justice inform transformation; (6) the limits of human nature; (7) the role of the utopian impulse; (8) working with the present to create new futures; and (9) human consciousness. In addition to presenting a set of research questions around these themes the paper highlights that much deeper engagement with complex social processes is required; that there are vast opportunities for social science, humanities and the arts to engage more directly with the climate challenge; that there is a need for a massive upscaling of efforts to understand and shape desired forms of change; and that, in addition to helping answer important questions about how to facilitate change, a key role of the social sciences, humanities and the arts in addressing climate change is to critique current societal patterns and to open up new thinking. Through such critique and by being more explicit about what is meant by transformation, greater opportunities will be provided for opening up a dialogue about change, possible futures and about what it means to re-shape the way in which people live

Economic Structures and Dynamics: A Morphogenetic View

Economic systems are characterised by constant change and evolution, and explanations concerning the properties of economic structures have received sustained interest. The structure of a system and its dynamics can influence each other through feedback effects. In this paper we offer a brief survey of how structure plays a role in dynamic economic theory – in particular, growth and business cycles. We propose a morphogenetic framework, inspired from the creation of forms in developmental biology, as a potential unifying approach for studying economic structures and their dynamics. We synthesise insights from three different strands of research, focusing on the role of coupling, diffusion and symmetry-breaking. We highlight their existing and prospective links with economics

Numerical Analysis of the Immersed Boundary Method for Cell-Based Simulation

Mathematical modelling provides a useful framework within which to investigate the organization of biological tissues. With advances in experimental biology leading to increasingly detailed descriptions of cellular behavior, models that consider cells as individual objects are becoming a common tool to study how processes at the single-cell level affect collective dynamics and determine tissue size, shape, and function. However, there often remains no comprehensive account of these models, their method of solution, computational implementation, or analysis of parameter scaling, hindering our ability to utilize and accurately compare different models. Here we present an efficient, open-source implementation of the immersed boundary (IB) method, tailored to simulate the dynamics of cell populations. This approach considers the dynamics of elastic membranes, representing cell boundaries, immersed in a viscous Newtonian fluid. The IB method enables complex and emergent cell shape dynamics, spatially heterogeneous cell properties, and precise control of growth mechanisms. We solve the model numerically using an established algorithm, based on the fast Fourier transform, providing full details of all technical aspects of our implementation. The implementation is undertaken within Chaste, an open-source C++ library that allows one to easily change constitutive assumptions. Our implementation scales linearly with time step, and subquadratically with mesh spacing and immersed boundary node spacing. We identify the relationship between the immersed boundary node spacing and fluid mesh spacing required to ensure fluid volume conservation within immersed boundaries, and the scaling of cell membrane stiffness and cell-cell interaction strength required when refining the immersed boundary discretization. Finally, we present a simulation study of a growing epithelial tissue to demonstrate the applicability of our implementation to relevant biological questions, highlighting several features of the IB method that make it well suited to address certain questions in epithelial morphogenesis