Coyote crossings: the role of smugglers in illegal immigration and border enforcement

Illegal immigration and border enforcement in the United States have increased concomitantly for over thirty years. One interpretation is that U.S. border policies have been ineffective. We offer an alternative view, extending the current immigration-enforcement literature by incorporating both the practice of people smuggling and a role for non-wage income into a two-country, dynamic general equilibrium model. We state conditions under which two steady state equilibria exist: one with a low level of capital, but relatively little migration. We then analyze two shocks: a positive technology shock to smuggling services and an increase in border enforcement. In the low-capital steady state, the capital-labor ratio declines with technological progress in smuggling, while illegal immigration increases. In the high-capital steady state, a technology shock causes the capital-labor ratio to rise while the effect on migration is indeterminate. We show that an increase in border enforcement is qualitatively equivalent to a negative technology shock to smuggling. Finally, we show that a developed country would never choose small levels of border enforcement over an open border. Moreover, a high level of border enforcement is optimal only if it significantly decreases capital accumulation. In addition, we provide conditions under which an increase in smuggler technology will lead to a decline in the optimal level of enforcement.Emigration and immigration ; Mexico

Non-Markovian dynamics in atom-laser outcoupling from a double-well Bose-Einstein condensate

We investigate the dynamics of a continuous atom laser based on the merging of independently formed atomic condensates. In a first attempt to understand the dynamics of the system, we consider two independent elongated Bose-Einstein condensates which approach each other and focus on intermediate inter-trap distances so that a two-mode model is well justified. In the framework of a mean-field theory, we discuss the quasi steady-state population of the traps as well as the energy distribution of the outcoupled atoms.Comment: 21 pages, 9 figure, to appear in J. Phys.

Coyote Crossings: The Role of Smugglers in Illegal Immigration and Border Enforcement

Illegal immigration and border enforcement in the United States have increased concomitantly for over thirty years. One interpretation is that U.S. border policies have been ineffective. We offer an alternative view, extending the current immigration-enforcement literature by incorporating both the practice of people smuggling and a role for non-wage income into a two- country, dynamic general equilibrium model. We state conditions under which two steady state equilibria exist: one with a low level of capital and high amount of illegal immigration and the other with a high level of capital, but relatively little migration. We then analyze two shocks: a positive technology shock to smuggling services and an increase in border enforcement. In the low-capital steady state, the capital-labor ratio declines with technological progress in smuggling, while illegal immigration increases. In the high-capital steady state, a technology shock causes the capital-labor ratio to rise while the effect on migration is indeterminate. We show that an increase in border enforcement is qualitatively equivalent to a negative technology shock to smuggling. Finally, we show that a developed country would never chose small levels of border enforcement over an open border. Moreover, a high level of border enforcement is optimal only if it significantly decreases capital accumulation. In addition we provide conditions under which an increase in smuggler technology will lead to a decline in the optimal level of enforcement

A Role for Sunspots in Explaining Endogenous Fluctutations in Illegal Immigration

In this paper we provide an alternative explanation for why illegal immigration can exhibit substantial fluctuations despite a constant wage gap. We develop a model economy in which migrants make decisions in the face of uncertain border enforcement and lump-sum transfers from the host country. The uncertainty is extrinsic in nature, a sunspot, and arises as a result of ambiguity regarding the commodity price of money. Migrants are restricted from participating in state-contingent insurance markets in the host country, whereas host country natives are not. We establish the existence of sunspot equilibria that are not mere randomizations over certainty equilibria. Volatility in migration flows stems from two distinct sources: the tension between transfers inducing migration and enforcement discouraging it and secondly the existence of a sunspot. Finally, we examine the impact of a change in tax/transfer policies by the government on migratio

Thermoelectric Properties from Ab Initio Calculations

As nanoscales become accessible to experimentalists, atomistic simulations of materials are becoming increasingly important for the prediction and design of materials properties. Recently, the search for energy efficient materials has driven the development of new theoretical methods, such as the Landauer-Datta-Lundstrom (LDL) generalized transport model, to explore thermoelectric properties of materials based on their electronic structure and lattice dynamics. The Landauer Transport Properties (LanTraP) tool, currently available in nanoHUB, allows the computation of thermoelectric transport coefficients from a full-band electron dispersion; however, generating such electron band structures from ab initio methods is a convoluted process. The aim of this project is to automate the generation of electron band dispersions using density functional theory (DFT) as implemented in the DFT materials properties simulator (DFTMatProp) nanoHUB tool. The new feature will produce the full-band electron dispersion of any material in a format suitable for use with LanTraP

Accounting for Fluctuations in Social Network Usage and Migration Dynamics

In this paper, we examine network capital usage and migration patterns in a theoretical model. Networks are modeled as impacting the migration decision in many ways. When young, larger networks reduce the time lost moving from one region to another. In addition networks decrease the time spent searching for a job. Finally, when old, migrants receive transfer payments through the network. We show that the number and properties of steady state equilibria as well as the global dynamics depend crucially on whether the returns to network capital accumulation exhibit constant, increasing, or decreasing returns to scales relative to the level of network capital. With constant returns to scale, migration flows and network capital levels are characterized by either a unique steady state equilibria or by a two-period cycle. The fluctuations in network capital usage exhibited by our model are consistent with recent empirical data regarding the usage of networks by Mexican immigrants. In the case of increasing returns to scale, either there exists a unique, stable steady state equilibria or multiple equilibria which are characterized as either sinks or saddles. When the returns to scale are decreasing, there exists a unique, stable steady state equilibrium. Finally, we show that increasing barriers to migration will result in an increase in the flow of immigrants, contrary to the desired effect, in the constant and increasing returns to scale cases