Votes and Vetoes: The Political Determinants of Commercial Openness

Societal theories of trade policy stress the importance of domestic interest groups, whereas statist theories focus on the effects of domestic institutions. Debates over the relative merits of these approaches have been fierce, but little systematic empirical research has been brought to bear on the relative merits of these theories. In this paper, we argue that, while societal and statist factors are generally regarded as having independent and competing effects, it is more fruitful to view the influence of each type of factor as conditional on the other. As societal explanations contend, deteriorating macroeconomic conditions are a potent source of protectionist pressures. The extent to which such conditions reduce commercial openness, however, depends centrally on the domestic institutions through which societal pressures must filter to influence policy. Two institutional features stand out. First, in states marked by greater fragmentation and more “veto points,” it is harder to change existing policies because any number of actors can block such change. Consequently, we expect the effects of macroeconomic conditions on trade policy to be weaker in fragmented states than in those characterized by a highly centralized national government. Second, we expect both fragmentation and the societal pressures stemming from the economy to have a more potent impact on trade policy in democracies than in other regimes, since the electoral constraints facing democratic leaders force them to respond to demands made by key segments of society. The results of our statistical tests covering more than one hundred countries during the period from 1980 to 2000 strongly support these arguments.http://deepblue.lib.umich.edu/bitstream/2027.42/40098/3/wp712.pd

On including quality in applied automatic gait recognition

Many gait recognition approaches use silhouette data. Imperfections in silhouette extraction have a negative effect on the performance of a gait recognition system. In this paper we extend quality metrics for gait recognition and evaluate new ways of using quality to improve a recognition system. We demonstrate use of quality to improve silhouette data and select gait cycles of best quality. The potential of the new approaches has been demonstrated experimentally on a challenging dataset, showing how recognition capability can be dramatically improved. Our practical study also shows that acquiring samples of adequate quality in arbitrary environments is difficult and that including quality analysis can improve performance markedly

Topological Twistons in Crystalline Polyethylene

We introduce an alternate model to describe twistons in crystalline polyethylene. The model couples torsional and longitudinal degrees of freedom and appears as an extension of a model that describes only the torsional motion. We find exact solutions that describe stable topological twistons, in good agreement with the torsional and longitudinal interactions in polyethylene.Comment: Latex, 10 pages; some stylistic corrections, to appear in Chemical Physics Letter

Boundary fermion currents and subleading order chiral anomaly in the AdS/CFT correspondence

We construct a wave-functional whose argument couples to boundary fermion currents in the AdS/CFT correspondence. Using this we calculate the contributions from bulk fermions to the chiral anomaly that give the subleading order term in the exact $N$-dependence of the chiral anomaly of ${\cal N}=4$ SYM. The result agrees with the calculation of Bilal & Chu.Comment: 6 page

Votes and Vetoes: The Political Determinants of Commercial Openness

Societal theories of trade policy stress the importance of domestic interest groups, whereas statist theories focus on the effects of domestic institutions. Debates over the relative merits of these approaches have been fierce, but little systematic empirical research has been brought to bear on the relative merits of these theories. In this paper, we argue that, while societal and statist factors are generally regarded as having independent and competing effects, it is more fruitful to view the influence of each type of factor as conditional on the other. As societal explanations contend, deteriorating macroeconomic conditions are a potent source of protectionist pressures. The extent to which such conditions reduce commercial openness, however, depends centrally on the domestic institutions through which societal pressures must filter to influence policy. Two institutional features stand out. First, in states marked by greater fragmentation and more “veto points,” it is harder to change existing policies because any number of actors can block such change. Consequently, we expect the effects of macroeconomic conditions on trade policy to be weaker in fragmented states than in those characterized by a highly centralized national government. Second, we expect both fragmentation and the societal pressures stemming from the economy to have a more potent impact on trade policy in democracies than in other regimes, since the electoral constraints facing democratic leaders force them to respond to demands made by key segments of society. The results of our statistical tests covering more than one hundred countries during the period from 1980 to 2000 strongly support these arguments.Protectionism, openness, veto players, veto points, positive political theory, unemployment, trade

Crescent Singularities in Crumpled Sheets

We examine the crescent singularity of a developable cone in a setting similar to that studied by Cerda et al [Nature 401, 46 (1999)]. Stretching is localized in a core region near the pushing tip and bending dominates the outer region. Two types of stresses in the outer region are identified and shown to scale differently with the distance to the tip. Energies of the d-cone are estimated and the conditions for the scaling of core region size R_c are discussed. Tests of the pushing force equation and direct geometrical measurements provide numerical evidence that core size scales as R_c ~ h^{1/3} R^{2/3}, where h is the thickness of sheet and R is the supporting container radius, in agreement with the proposition of Cerda et al. We give arguments that this observed scaling law should not represent the asymptotic behavior. Other properties are also studied and tested numerically, consistent with our analysis.Comment: 13 pages with 8 figures, revtex. To appear in PR

Finite VEVs from a Large Distance Vacuum Wave Functional

We show how to compute vacuum expectation values from derivative expansions of the vacuum wave functional. Such expansions appear to be valid only for slowly varying fields, but by exploiting analyticity in a complex scale parameter we can reconstruct the contribution from rapidly varying fields.Comment: 39 pages, 16 figures, LaTeX2e using package graphic

Spontaneous curvature cancellation in forced thin sheets

In this paper we report numerically observed spontaneous vanishing of mean curvature on a developable cone made by pushing a thin elastic sheet into a circular container. We show that this feature is independent of thickness of the sheet, the supporting radius and the amount of deflection. Several variants of developable cone are studied to examine the necessary conditions that lead to the vanishing of mean curvature. It is found that the presence of appropriate amount of radial stress is necessary. The developable cone geometry somehow produces the right amount of radial stress to induce just enough radial curvature to cancel the conical azimuthal curvature. In addition, the circular symmetry of supporting container edge plays an important role. With an elliptical supporting edge, the radial curvature overcompensates the azimuthal curvature near the minor axis and undercompensates near the major axis. Our numerical finding is verified by a crude experiment using a reflective plastic sheet. We expect this finding to have broad importance in describing the general geometrical properties of forced crumpling of thin sheets.Comment: 13 pages, 12 figures, revtex

SP-100 reactor with Brayton conversion for lunar surface applications

Examined here is the potential for integrating Brayton-cycle power conversion with the SP-100 reactor for lunar surface power system applications. Two designs were characterized and modeled. The first design integrates a 100-kWe SP-100 Brayton power system with a lunar lander. This system is intended to meet early lunar mission power needs while minimizing on-site installation requirements. Man-rated radiation protection is provided by an integral multilayer, cylindrical lithium hydride/tungsten (LiH/W) shield encircling the reactor vessel. Design emphasis is on ease of deployment, safety, and reliability, while utilizing relatively near-term technology. The second design combines Brayton conversion with the SP-100 reactor in a erectable 550-kWe powerplant concept intended to satisfy later-phase lunar base power requirements. This system capitalizes on experience gained from operating the initial 100-kWe module and incorporates some technology improvements. For this system, the reactor is emplaced in a lunar regolith excavation to provide man-rated shielding, and the Brayton engines and radiators are mounted on the lunar surface and extend radially from the central reactor. Design emphasis is on performance, safety, long life, and operational flexibility