Duncan K. Foley

The economy needs agent-based modelling

The leaders of the world are flying the economy by the seat of their pants, say J. Doyne Farmer and Duncan Foley. There is, however, a better way to help guide financial policies.

Decentralized, dispersed exchange without an auctioneer: A simulation study☆

Abstract We stimulate exchange among geographically dispersed agents who face real costs of communication along with bounds to rationality and calculation. Exchange is entirely decentralized it is initiated by individual agents who broadcast costly messages indicating their interest in trade; it is accomplished by bilateral bargaining between pairs of agents; agents use the information gained from previous attempts at local trade to calculate their search strategies for succeeding rounds. This decentralized mechanism can achieve a substantial improvement in the allocation of resources and the average welfare of agents in comparison with a randomized initial endowment. But in comparison with Walrasian equilibrium agents who begin with endowments of equal value end up with substantially unequal wealth, although the initial inequality of utility is reduced.

Recent Developments in the Labor Theory of Value

This paper reviews the historical roots of Marxs labor theory of value and some contemporary contributions to the critique of this theory. Modern commentary on Marxs labor theory of value based on dual system of parallel prices and embodied labor coefficients loses sight of the theorys roots in the philosophy of historical materialism and its function as a theory of money. Recently developed empirical single system approaches, including the New Interpretation that identifies the monetary expression of labor time with the ratio of money value added to living productive labor expended in its production, address these problems, and open the possibility of a progressive research program based on Marxs theory.

Gates and Oscillators II: Zeitgebers and the Network Model of the Brain Clock

Circadian rhythms in physiology and behavior are regulated by the SCN. When assessed by expression of clock genes, at least 2 distinct functional cell types are discernible within the SCN: nonrhythmic, light-inducible, retinorecipient cells and rhythmic autonomous oscillator cells that are not directly retinorecipient. To predict the responses of the circadian system, the authors have proposed a model based on these biological properties. In this model, output of rhythmic oscillator cells regulates the activity of the gate cells. The gate cells provide a daily organizing signal that maintains phase coherence among the oscillator cells. In the absence of external stimuli, this arrangement yields a multicomponent system capable of producing a self-sustained consensus rhythm. This follow-up study considers how the system responds when the gate cells are activated by an external stimulus, simulating a response to an entraining (or phase-setting) signal. In this model, the authors find that the system can be entrained to periods within the circadian range, that the free-running system can be phase shifted by timed activation of the gate, and that the phase response curve for activation is similar to that observed when animals are exposed to a light pulse. Finally, exogenous triggering of the gate over a number of days can organize an arrhythmic system, simulating the light-dependent reappearance of rhythmicity in a population of disorganized, independent oscillators. The model demonstrates that a single mechanism (i.e., the output of gate cells) can account for not only free-running and entrained rhythmicity but also other circadian phenomena, including limits of entrainment, a PRC with both delay and advance zones, and the light-dependent reappearance of rhythmicity in an arrhythmic animal.

Liquidity-profit rate cycles in a capitalist economy

Abstract A monetary economy consisting of independent capitalist firms, in which workers spend wages instantly and labor is not scarce, is studied The firms create demand for each others output through their capital outlays, and create the backing for money through borrowing. When all firms are identical in behavior and initial conditions, and the rate of growth of money is constant, the economy may be unstable around the equilibrium steady state growth path due to strong accelerator effects, and follow a limit cycle trajectory.

Characterization of orderly spatiotemporal patterns of clock gene activation in mammalian suprachiasmatic nucleus

Because we can observe oscillation within individual cells and in the tissue as a whole, the suprachiasmatic nucleus (SCN) presents a unique system in the mammalian brain for the analysis of individual cells and the networks of which they are a part. While dispersed cells of the SCN sustain circadian oscillations in isolation, they are unstable oscillators that require network interactions for robust cycling. Using cluster analysis to assess bioluminescence in acute brain slices from PERIOD2::Luciferase (PER2::LUC) knockin mice, and immunochemistry of SCN from animals harvested at various circadian times, we assessed the spatiotemporal activation patterns of PER2 to explore the emergence of a coherent oscillation at the tissue level. The results indicate that circadian oscillation is characterized by a stable daily cycle of PER2 expression involving orderly serial activation of specific SCN subregions, followed by a silent interval, with substantial symmetry between the left and right side of the SCN. The biological significance of the clusters identified in living slices was confirmed by co‐expression of LUC and PER2 in fixed, immunochemically stained brain sections, with the spatiotemporal pattern of LUC expression resembling that revealed in the cluster analysis of bioluminescent slices. We conclude that the precise timing of PER2 expression within individual neurons is dependent on their location within the nucleus, and that small groups of neurons within the SCN give rise to distinctive and identifiable subregions. We propose that serial activation of these subregions is the basis of robustness and resilience of the daily rhythm of the SCN.

Unholy Trinity : Labor, Capital and Land in the New Economy

Part I - Complexity and Political Economy Part II - Innovation and Distribution Part III - Global Warming Part IV - Population Part V - Concluding Observations

Distribution and Capacity Utilization: Conceptual Issues and Empirical Evidence

This paper examines the relationship between the distribution of income and capacity utilization in the context of the Kaleckian model of growth and distribution. We provide an exposition of the underlying theory of wage- and profit-led growth. We emphasize the implications of possible non-linearities in the determination of the final equilibrium and why—because of them—a redefinition of the concept of wage- and profit-led economy is necessary. We estimate the demand and distribution schedule for the US economy using a two-stage least squares approach. Our findings confirm the hypothesis of a non-linear distribution schedule and therefore the need to redefine the concepts wage- and profit-led growth.

Endogenous technical change with externalities in a classical growth model

Abstract A growth model with three inputs (capital, labor, and land) extends Foley and Michl’s [D. Foley, T.R. Michl’s, Growth and Distribution, Harvard University Press, Cambridge, MA, 1999] classical accumulation model by adding a Goodwin [R. Goodwin, A growth cycle, in: C.H. Feinstein (Ed.), Socialism, Capitalism and Economic Growth, Cambridge University Press, Cambridge, 1967] labor market and a model of endogenous technical change that can represent either Dumenil and Levy’s [Metroeconomica 46 (1995) 213; J. Econ. Behav. Org., this issue] or Kennedy’s [Econ. J. 74 (295) (1964) 541] models. When land is priced, there is a stable steady-state growth path with desirable allocational properties. When land is not priced, no steady state exists and the growth path leads to a catastrophe. These results hold when the elasticity of substitution between capital and labor is less than unity.

Differential contributions of intra‐cellular and inter‐cellular mechanisms to the spatial and temporal architecture of the suprachiasmatic nucleus circadian circuitry in wild‐type, cryptochrome‐null and vasoactive intestinal peptide receptor 2‐null mutant mice

To serve as a robust internal circadian clock, the cell‐autonomous molecular and electrophysiological activities of the individual neurons of the mammalian suprachiasmatic nucleus (SCN) are coordinated in time and neuroanatomical space. Although the contributions of the chemical and electrical interconnections between neurons are essential to this circuit‐level orchestration, the features upon which they operate to confer robustness to the ensemble signal are not known. To address this, we applied several methods to deconstruct the interactions between the spatial and temporal organisation of circadian oscillations in organotypic slices from mice with circadian abnormalities. We studied the SCN of mice lacking Cryptochrome genes (Cry1 and Cry2), which are essential for cell‐autonomous oscillation, and the SCN of mice lacking the vasoactive intestinal peptide receptor 2 (VPAC2‐null), which is necessary for circuit‐level integration, in order to map biological mechanisms to the revealed oscillatory features. The SCN of wild‐type mice showed a strong link between the temporal rhythm of the bioluminescence profiles of PER2::LUC and regularly repeated spatially organised oscillation. The Cry‐null SCN had stable spatial organisation but lacked temporal organisation, whereas in VPAC2‐null SCN some specimens exhibited temporal organisation in the absence of spatial organisation. The results indicated that spatial and temporal organisation were separable, that they may have different mechanistic origins (cell‐autonomous vs. interneuronal signaling) and that both were necessary to maintain robust and organised circadian rhythms throughout the SCN. This study therefore provided evidence that the coherent emergent properties of the neuronal circuitry, revealed in the spatially organised clusters, were essential to the pacemaking function of the SCN.