Think Locally, Act Locally: Spillovers, Spillbacks, and Efficient Decentralized Policymaking

In this paper, we analyze a class of models in which there are interjurisdictional spillovers among heterogeneous jurisdictions, as illustrated for instance by CO2 emissions that affect the global environment. Each jurisdiction’s emissions depend upon the local stock of private capital. Capital is interjurisdictionally-mobile and may be taxed to help finance local public expenditures. We show that decentralized policymaking leads to efficient resource allocations in important cases, even in the complete absence of corrective interventions by higher-level governments or coordination of policy through Coasian bargaining. In particular, even when the preferences and production technologies differ among the agents, the decentralized system can still result in globally efficient allocation.

Hypothesis testing for Gaussian states on bosonic lattices

The asymptotic state discrimination problem with simple hypotheses is considered for a cubic lattice of bosons. A complete solution is provided for the problems of the Chernoff and the Hoeffding bounds and Stein's lemma in the case when both hypotheses are gauge-invariant Gaussian states with translation-invariant quasi-free parts.Comment: 22 pages, submitted versio

Think locally, act locally: spillovers, spillbacks, and efficient decentralized policymaking

In this paper, we analyze a class of models in which there are interjurisdictional spillovers among heterogeneous jurisdictions, as illustrated for instance by CO2 emissions that affect the global environment. Each jurisdiction's emissions depend upon the local stock of private capital. Capital is interjurisdictionally-mobile and may be taxed to help finance local public expenditures. We show that decentralized policymaking leads to efficient resource allocations in important cases, even in the complete absence of corrective interventions by higher-level governments or coordination of policy through Coasian bargaining. In particular, even when the preferences and production technologies differ among the agents, the decentralized system can still result in globally efficient allocation

Spontaneous thermal runaway as an ultimate failure mechanism of materials

The first theoretical estimate of the shear strength of a perfect crystal was given by Frenkel [Z. Phys. 37, 572 (1926)]. He assumed that as slip occurred, two rigid atomic rows in the crystal would move over each other along a slip plane. Based on this simple model, Frenkel derived the ultimate shear strength to be about one tenth of the shear modulus. Here we present a theoretical study showing that catastrophic material failure may occur below Frenkel's ultimate limit as a result of thermal runaway. We demonstrate that the condition for thermal runaway to occur is controlled by only two dimensionless variables and, based on the thermal runaway failure mechanism, we calculate the maximum shear strength $\sigma_c$ of viscoelastic materials. Moreover, during the thermal runaway process, the magnitude of strain and temperature progressively localize in space producing a narrow region of highly deformed material, i.e. a shear band. We then demonstrate the relevance of this new concept for material failure known to occur at scales ranging from nanometers to kilometers.Comment: 4 pages, 3 figures. Eq. (6) and Fig. 2a corrected; added references; improved quality of figure

Point defect concentrations in metastable Fe-C alloys

Point defect species and concentrations in metastable Fe-C alloys are determined using density functional theory and a constrained free-energy functional. Carbon interstitials dominate unless iron vacancies are in significant excess, whereas excess carbon causes greatly enhances vacancy concentration. Our predictions are amenable to experimental verification; they provide a baseline for rationalizing complex microstructures known in hardened and tempered steels, and by extension other technological materials created by or subjected to extreme environments

On the definition of Quantum Free Particle on Curved Manifolds

A selfconsistent definition of quantum free particle on a generic curved manifold emerges naturally by restricting the dynamics to submanifolds of co-dimension one. PACS 0365 0240Comment: 8 p., phyzzx macropackag

Judging the impact of leadership-development activities on school practice

The nature and effectiveness of professional-development activities should be judged in a way that takes account of both the achievement of intended outcomes and the unintended consequences that may result. Our research project set out to create a robust approach that school staff members could use to assess the impact of professional-development programs on leadership and management practice without being constrained in this judgment by the stated aims of the program. In the process, we identified a number of factors and requirements relevant to a wider audience than that concerned with the development of leadership and management in England. Such an assessment has to rest upon a clear understanding of educational leadership,a clearly articulated model of practice, and a clear model of potential forms of impact. Such foundations, suitably adapted to the subject being addressed, are appropriate for assessing all teacher professional development

Polymers in Curved Boxes

We apply results derived in other contexts for the spectrum of the Laplace operator in curved geometries to the study of an ideal polymer chain confined to a spherical annulus in arbitrary space dimension D and conclude that the free energy compared to its value for an uncurved box of the same thickness and volume, is lower when $D < 3$, stays the same when $D = 3$, and is higher when \mbox{$D > 3$}. Thus confining an ideal polymer chain to a cylindrical shell, lowers the effective bending elasticity of the walls, and might induce spontaneous symmetry breaking, i.e. bending. (Actually, the above mentioned results show that {\em {any}} shell in $D = 3$ induces this effect, except for a spherical shell). We compute the contribution of this effect to the bending rigidities in the Helfrich free energy expression.Comment: 20 pages RevTeX, epsf; 4 figures; submitted to Macromoledule