The space particle environment

The energetic charged particle environment in the Earth's magnetosphere was studied. An overview is provided of trapped particle morphology, the geometry of the trapping regions, the radiation environmental models, the current status of these models, and future modelling requirements

Aharonov-Bohm Problem for Spin-One

The basic AB problem is to determine how an unshielded tube of magnetic flux $\Phi$ affects arbitrarily long-wavelength charged particles impinging on it. For spin-1 at almost all $\Phi$ the particles do not penetrate the tube, so the interaction essentially is periodic in $\Phi$ (AB effect). Below-threshold bound states move freely only along the tube axis, and consequent induced vacuum currents supplement rather than screen $\Phi$. For a pure magnetic interaction the tube must be broader than the particle Compton wavelength, i.e., only the nonrelativistic spin-1 AB problem exists.Comment: 15 pages, Late

HUMAN CAPITAL NEEDS OF BLACK LAND-GRANT INSTITUTIONS

Labor and Human Capital, Teaching/Communication/Extension/Profession,

The Term Spread International Evidence of Non-Linear Adjustment

This study tests whether changes in the short-term interest rate can best be modelled in a nonlinear fashion. We argue that there are good theoretical and empirical reasons for adopting this strategy. Using monthly data from several industrialized countries, namely Canada, Germany, Sweden, Switzerland, UK, and US, we show that the short-term interest rate movements are better explained, usually via the exponential smooth transition autoregression (ESTR). Unlike the existing literature on non-linear estimation, we consider a number of candidates for the transition variable. These include: an error correction term, estimated from an underlying cointegrating relationship predicted by the expectations hypothesis, the US spread, the domestic spread, inflation and output growth forecasts, and deviations from an inflation target in the case of Canada, the UK and Sweden. The sample spans the period from 1960-1998. We cannot reject non-linearity in the behavior of interest rate changes most often when the (lagged) domestic spread serves as the transition variable. In the case of the inflation targeting countries in our sample, the most appropriate transition variable can be the deviation from the publicly announced inflation target. We supplement estimates with extensive diagnostic testing to ensure that we can reject the linear alternative with reasonable confidence. We believe that changes in central bank policies and in the reaction of market participants over time to such changes argue in favor of the non-linear estimation approach. We would also argue that any model of the term spread over a fairly long span of time necessitates resort to non-linear estimation methods.

Resource-Constrained Adaptive Search and Tracking for Sparse Dynamic Targets

This paper considers the problem of resource-constrained and noise-limited localization and estimation of dynamic targets that are sparsely distributed over a large area. We generalize an existing framework [Bashan et al, 2008] for adaptive allocation of sensing resources to the dynamic case, accounting for time-varying target behavior such as transitions to neighboring cells and varying amplitudes over a potentially long time horizon. The proposed adaptive sensing policy is driven by minimization of a modified version of the previously introduced ARAP objective function, which is a surrogate function for mean squared error within locations containing targets. We provide theoretical upper bounds on the performance of adaptive sensing policies by analyzing solutions with oracle knowledge of target locations, gaining insight into the effect of target motion and amplitude variation as well as sparsity. Exact minimization of the multi-stage objective function is infeasible, but myopic optimization yields a closed-form solution. We propose a simple non-myopic extension, the Dynamic Adaptive Resource Allocation Policy (D-ARAP), that allocates a fraction of resources for exploring all locations rather than solely exploiting the current belief state. Our numerical studies indicate that D-ARAP has the following advantages: (a) it is more robust than the myopic policy to noise, missing data, and model mismatch; (b) it performs comparably to well-known approximate dynamic programming solutions but at significantly lower computational complexity; and (c) it improves greatly upon non-adaptive uniform resource allocation in terms of estimation error and probability of detection.Comment: 49 pages, 1 table, 11 figure

Reparations Talk: Reparations for Slavery and the Tort Law Analogy

This Article examines the current landscape of reparations for slavery, identifying the contours of reparations lawsuits and exploring the ability of tort law to help apportion moral culpability in the reparations context. It first examines several possibilities for lawsuits for Jim Crow, discussing constitutional requirements and identifying specific incidents such as lynchings and Jim Crow legislation-that might be appropriate subjects of litigation. The Article then assesses the viability of obtaining reparations through tort and unjust enrichment claims by addressing issues such as causation and damages, exploring the obstacles presented by American law\u27s liberalism, and identifying the various goals of reparations advocates. Finally, the Article moves beyond litigation to contemplate the ability of tort law to serve as a vehicle for framing discussions about moral culpability. It concludes with an optimistic assessment of the role of tort law in the reparations movement