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The structure of a system of retail centres as described by their size, composition, and location, is a result of competition among the centres for customers. The evolution of the system is described by a set of cost and revenue equations. The revenue equations include a distance decay parameter. When this parameter is below a critical value, retail activity tends to agglomerate in a major, centrally located centre; otherwise, it tends to be dispersed among a number of similar centres. This fundamental bifurcation appears in actual retail systems. It underlies such phenomena as itinerant medieval trade fairs, the historical migration of the major retail centre of cities like London and New York, and innovations like the department store, the regional mall, and power centres. Since a lower distance decay parameter is associated with higher energy densities, a direct link is established between spatial structure, energy, and technology.

This chapter deal primarily with the period following the first world war, and starts with a discussion of the relationship between overall changes in the Mashreq and the Maghreb. It then focuses on a number of crucial common areas. The one is women’s rights with regard to legal capacity, inheritance, dress, education and visibility. The other concerns civil legislation and the drawing up of civil codes. Controversies on both issues and attempts at pushing back by the religious institutions are discussed. The relative marginalisation of religious culture, cognitive challenges to religion, and the religious assault on the the cognitive and social goods of modernity, are addressed in detail. The incubation and early deployment of fundamentalism in politics and culture are analysed in relation to objective transformations in place.

This chapter transports the reader into the aisles of a New England Whole Foods Market, through the stalls of a regional farmers’ market, and into the fields of Scenic View Farm to introduce the challenges faced when trying to understand small farmers’ practices in light of the contemporary agricultural economy. It then outlines dominant theories in the study of organic agriculture, such as conventionalization and bifurcation, which often focus centrally on the market conditions and regulatory environment of the organic sector at the expense of the everyday practices of organic farmers. The chapter then introduces theoretical constructs of good matches and relational work from economic sociology as a means of understanding how small farmers balance market conditions with a host of other concerns in their routine farming practices and economic decisions. Finally, the chapter outlines the organization of the book, which moves from the broader history and context of organic agriculture to the everyday experiences of the farmers at Scenic View, before looking to the future of sustainable farming practices.

In 2000, a radical shift occurred in the organic food system: the majority of organic food in the United States began to be sold in ordinary supermarkets. This chapter examines how the regulatory focus on chemical inputs facilitated the fragmentation and homogenization of organic farming, yielding a conventionalized organic industry capable of delivering food at a supermarket-sized scale. It also examines how these processes limit organic agriculture’s potential to represent a sustainable solution to the problems of modern food systems. This chapter begins with a discussion of what environmental, social, and economic sustainability in the food system would entail. It then examines the concentration of industrial influence in the organic sector in the wake of the federal organic standards, and looks critically at whether industrial organic practices can meet the challenges of sustainability. Finally, the chapter points to theories of bifurcation, which examine structural positions within capitalist agriculture that may offer spaces for alternative farming practices, particularly in places like New England. This chapter also notes, however, that such approaches focus on the political economy of agriculture, leaving the relational strategies alternative farmers use to take advantage of such structural holes unexplored.

Electromechanics—coupling of mechanical forces with others—exhibits a continuum-to-discrete spectrum of properties. In this chapter, classical and newer analysis techniques are developed for devices ranging from inertial sensors to scanning probes to quantify limits and sensitivities. Mechanical response, energy storage, transduction and dynamic characteristics of various devices are analyzed. The Lagrangian approach is developed for multidomain analysis and to bring out nonlinearity. The approach is extended to nanoscale fluidic systems where nonlinearities, fluctuation effects and the classical-quantum boundary is quite central. This leads to the study of measurement limits using power spectrum and, correlations with slow and fast forces. After a diversion to acoustic waves and piezoelectric phenomena, nonlinearities are explored in depth: homogeneous and forced conditions of excitation, chaos, bifurcations and other consequences, Melnikov analysis and the classic phase portaiture. The chapter ends with comments on multiphysics such as of nanotube-based systems and electromechanobiological biomotor systems.

The previous chapter provided a detailed description of the currents underlying the generation and propagation of action potentials in the squid giant axon. The Hodgkin-Huxley (1952d) model captures these events in terms of the dynamical behavior of four variables: the membrane potential and three state variables determining the state of the fast sodium and the delayed potassium conductances. This quantitative, conductance-based formalism reproduces the physiological data remarkably well and has been extremely fertile in terms of providing a mathematical framework for modeling neuronal excitability throughout the animal kingdom (for the current state of the art, see McKenna, Davis, and Zornetzer, 1992; Bower and Beeman, 1998; Koch and Segev, 1998). Collectively, these models express the complex dynamical behaviors observed experimentally, including pulse generation and threshold behavior, adaptation, bursting, bistability, plateau potentials, hysteresis, and many more. However, these models are difficult to construct and require detailed knowledge of the kinetics of the individual ionic currents. The large number of associated activation and inactivation functions and other parameters usually obscures the contributions of particular features (e.g., the activation range of the sodium activation particle) toward the observed dynamic phenomena. Even after many years of experience in recording from neurons or modeling them, it is a dicey business predicting the effect that varying one parameter, say, the amplitude of the calcium-dependent slow potassium current (Chap. 9), has on the overall behavior of the model. This precludes the development of insight and intuition, since the numerical complexity of these models prevents one from understanding which important features in the model are responsible for a particular phenomenon and which are irrelevant. Qualitative models of neuronal excitability, capturing some of the topological aspects of neuronal dynamics but at a much reduced complexity, can be very helpful in this regard, since they highlight the crucial features responsible for a particular behavior. By topological aspects we mean those properties that remain unchanged in spite of quantitative changes in the underlying system. These typically include the existence of stable solutions and their basins of attraction, limit cycles, bistability, and the existence of strange attractors.