Chaos vs. patience in a macroeconomic model of capital accumulation: New applications of a uniform neighborhood turnpike theorem

We present in this paper some new results on the strong incompatibility between chaos and patience in a macroeconomic model of capital accumulation. These results are explicit and non-trivial applications of the general theorem proven in Guerrero-Luchtenberg (2000), in which the statement (theorem 2) ‘chaos vanishes as the discount factor tends to one’, is formally presented. Here, we show precisely how this statement applies to some important indicators of chaos not analyzed before. Furthermore, we will show that, for a given family of optimal growth models, there is a bound on the discount factor such that any type of chaos is negligible.

Cyclic Pricing by a Durable Goods Monopolist: Corrigendum

In this paper we make a new analysis of the model presented in Conlisk, Gerstner and Sobel (1984). They propose a model in discrete time, such that at each period a new cohort of agents enters the market –each cohort is composed by two types of agents, high value and low value agents– and a monopolist offering a durable good. They argue that in this model the monopolist charge a cyclic price path as a subgame perfect equilibrium. Instead of this, we show that either the monopolist charge a single price forever as a subgame perfect equilibrium or a subgame perfect equilibrium does not exist.Durable goods, monopolist, heterogenous agents, subgame perfect equilibrium

Study of alkaline hydrothermal activation of belite cements by thermal analysis

The effect of alkaline hydrothermal activation of class-C fly ash belite cement was studied using thermal analysis (TG/DTG) by determining the increase in the combined water during a period of hydration of 180 days. The results were compared with those obtained for a belite cement hydrothermally activated in water. The two belite cements were fabricated via the hydrothermal-calcination route of class-C fly ash in 1 M NaOH solution (FABC-2-N) or demineralised water (FABC-2-W). From the results, the effect of the alkaline hydrothermal activation of belite cement (FABC-2-N) was clearly differentiated, mainly at early ages of hydration, for which the increase in the combined water was markedly higher than that of the belite cement that was hydrothermally activated in water. Important direct quantitative correlations were obtained among physicochemical parameters, such as the combined water, the BET surface area, the volume of nano-pores, and macro structural engineering properties such as the compressive mechanical strength

The Network Picture of Labor Flow

We construct a data-driven model of flows in graphs that captures the essential elements of the movement of workers between jobs in the companies (firms) of entire economic systems such as countries. The model is based on the observation that certain job transitions between firms are often repeated over time, showing persistent behavior, and suggesting the construction of static graphs to act as the scaffolding for job mobility. Individuals in the job market (the workforce) are modelled by a discrete-time random walk on graphs, where each individual at a node can possess two states: employed or unemployed, and the rates of becoming unemployed and of finding a new job are node dependent parameters. We calculate the steady state solution of the model and compare it to extensive micro-datasets for Mexico and Finland, comprised of hundreds of thousands of firms and individuals. We find that our model possesses the correct behavior for the numbers of employed and unemployed individuals in these countries down to the level of individual firms. Our framework opens the door to a new approach to the analysis of labor mobility at high resolution, with the tantalizing potential for the development of full forecasting methods in the future.Comment: 27 pages, 6 figure

The Economic Impact of the Cotton Crop on the Texas High Plains, 2008

Early season high winds and late season cool temperatures have worked together to limit the size of the High Plains cotton crop. Over the past 5 years, the High Plains2 has averaged 4.44 million bales produced each year. However, Plains Cotton Growers recently estimated the 2008 crop to be around 3.2 million bales (Wade). If these production numbers materialize, the 28% drop in production will have significant impacts on the regional economy. The purposes of this briefing paper are to: (1) estimate the impact of the cotton crop on the High Plains economy, and (2) estimate the impact of a smaller than average crop.Agribusiness,

How to excite the internal modes of sine-Gordon solitons

We investigate the dynamics of the sine-Gordon solitons perturbed by spatiotemporal external forces. We prove the existence of internal (shape) modes of sine-Gordon solitons when they are in the presence of inhomogeneous space-dependent external forces, provided some conditions (for these forces) hold. Additional periodic time-dependent forces can sustain oscillations of the soliton width. We show that, in some cases, the internal mode even can become unstable, causing the soliton to decay in an antisoliton and two solitons. In general, in the presence of spatiotemporal forces the soliton behaves as a deformable (non-rigid) object. A soliton moving in an array of inhomogeneities can also present sustained oscillations of its width. There are very important phenomena (like the soliton-antisoliton collisions) where the existence of internal modes plays a crucial role. We show that, under some conditions, the dynamics of the soliton shape modes can be chaotic. A short report of some of our results has been published in [J. A. Gonzalez et al., Phys. Rev. E, 65 (2002) 065601(R)].Comment: 14 .eps figures.To appear in Chaos, Solitons and Fractal

Frictional Unemployment on Labor Flow Networks

We develop an alternative theory to the aggregate matching function in which workers search for jobs through a network of firms: the labor flow network. The lack of an edge between two companies indicates the impossibility of labor flows between them due to high frictions. In equilibrium, firms' hiring behavior correlates through the network, generating highly disaggregated local unemployment. Hence, aggregation depends on the topology of the network in non-trivial ways. This theory provides new micro-foundations for the Beveridge curve, wage dispersion, and the employer-size premium. We apply our model to employer-employee matched records and find that network topologies with Pareto-distributed connections cause disproportionately large changes on aggregate unemployment under high labor supply elasticity