Increasing Spectrum for Broadband: What Are The Options?

The growth of wireless broadband is a bright spot in the U.S. economy, but a shortage of flexibly licensed spectrum rights could put a crimp on this expansion. Freeing up spectrum from other uses would allow greater expansion of wireless broadband and would bring substantial gains—likely in the hundreds of billions of dollars—for U.S. consumers, businesses, and the federal treasury. ... U.S. experience suggests that it takes at least six years, and possibly over a decade, to complete any large-scale reallocation of spectrum. Thus, for policymakers, the ?projected? need is actually here today. This paper makes three proposals to increase spectrum available for wireless broadband under a flexibly licensed, market-based regime.

Application of CFD to sonic boom near and mid flow-field prediction

A 3-D parabolized Navier-Stokes (PNS) code was used to calculate the supersonic overpressures from three different geometries at near- and mid-flow fields. Wind tunnel data is used for code validation. Comparison of the computed results with different grid refinements is shown. It is observed that a large number of grid points is needed to resolve the tail shock/expansion fan interaction. Therefore, an adaptive grid approach is employed to calculate the flow field. The agreement between the numerical results and the wind tunnel data confirms that computational fluid dynamics can be applied to the problem of sonic boom prediction

Stability and Absence of Binding for Multi-Polaron Systems

We resolve several longstanding problems concerning the stability and the absence of multi-particle binding for N\geq 2 polarons. Fr\"ohlich's 1937 polaron model describes non-relativistic particles interacting with a scalar quantized field with coupling \sqrt\alpha, and with each other by Coulomb repulsion of strength U. We prove the following: (i) While there is a known thermodynamic instability for U<2\alpha, stability of matter does hold for U>2\alpha, that is, the ground state energy per particle has a finite limit as N\to\infty. (ii) There is no binding of any kind if U exceeds a critical value that depends on \alpha but not on N. The same results are shown to hold for the Pekar-Tomasevich model.Comment: 23 page

Ground state properties of multi-polaron systems

We summarize our recent results on the ground state energy of multi-polaron systems. In particular, we discuss stability and existence of the thermodynamic limit, and we discuss the absence of binding in the case of large Coulomb repulsion and the corresponding binding-unbinding transition. We also consider the Pekar-Tomasevich approximation to the ground state energy and we study radial symmetry of the ground state density.Comment: Contribution to the proceedings of ICMP12, Aalborg, Denmark, August 6--11, 2012; 8 page

Binding, Stability, and Non-binding of Multi-polaron Systems

The binding of polarons, or its absence, is an old and subtle topic. After defining the model we state some recent theorems of ours. First, the transition from many-body collapse to the existence of a thermodynamic limit for N polarons occurs precisely at U=2\alpha, where U is the electronic Coulomb repulsion and \alpha is the polaron coupling constant. Second, if U is large enough, there is no multi-polaron binding of any kind. We also discuss the Pekar-Tomasevich approximation to the ground state energy, which is valid for large \alpha. Finally, we derive exact results, not reported before, about the one-dimensional toy model introduced by E. P. Gross.Comment: 12 pages; contribution to the proceedings of the conference QMath 11 (Hradec Kralove, September 2010); clarification added after Theorem 4.

The Scientific Reach of Multi-Ton Scale Dark Matter Direct Detection Experiments

The next generation of large scale WIMP direct detection experiments have the potential to go beyond the discovery phase and reveal detailed information about both the particle physics and astrophysics of dark matter. We report here on early results arising from the development of a detailed numerical code modeling the proposed DARWIN detector, involving both liquid argon and xenon targets. We incorporate realistic detector physics, particle physics and astrophysical uncertainties and demonstrate to what extent two targets with similar sensitivities can remove various degeneracies and allow a determination of dark matter cross sections and masses while also probing rough aspects of the dark matter phase space distribution. We find that, even assuming dominance of spin-independent scattering, multi-ton scale experiments still have degeneracies that depend sensitively on the dark matter mass, and on the possibility of isospin violation and inelasticity in interactions. We find that these experiments are best able to discriminate dark matter properties for dark matter masses less than around 200 GeV. In addition, and somewhat surprisingly, the use of two targets gives only a small improvement (aside from the advantage of different systematics associated with any claimed signal) in the ability to pin down dark matter parameters when compared with one target of larger exposure.Comment: 23 pages; updated to match PRD versio

Good Bye Traditional Budgeting, Hello Rolling Forecast: Has The Time Come?

This paper argues for a new approach to accounting textbook budgeting material. The business environment is not stable. Change is continuous, for large and small business alike. A business must act and react to generate shareholder value. The rolling forecast provides the necessary navigational insight. The traditional annual static budget does not. Managing a business, looking inwards and backwards and making decisions to hit the annual budget target no longer serves management in generating shareholder value. In most situations this approach to company management only leads to compromised performance. Leadership may not reach long-term shareholder wealth potential in using the traditional annual budget as a command and control device. Our research shows companies are moving to a rolling forecast as a management navigational tool. Leadership uses the forecast to navigate continuous change in creating shareholder value. This paper demonstrates how to build leadership concepts that go along with the rolling forecast, as well as the rolling forecast process itself into the classroom and accounting textbook material. Accounting and graduate business students need this type of education to help lead and increase a business’ chances of success

Bicycle Safety Supplement to Teacher Buggy Driving Safety Curriculum

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Self-Interest, Love, and Economic Justice: A Dialogue Between Classical Economic Liberalism and Catholic Social Teaching

This essay seeks to start a dialogue between two traditions that historically have interpreted the economy in opposing ways: the individualism of classic economic liberalism (CEL), represented by Adam Smith and Milton Friedman, and the communitarianism of Catholic social teaching (CST), interpreted primarily through the teachings of popes and secondarily the U.S. Catholic bishops. The present authors, an economist and a moral theologian who identify with one or the other of the two traditions, strive to clarify objectively their similarities and differences with the opposing perspective. Section one focuses on each position\u27s perspective of love of self and love of others. We find both CEL and CST saying that self-love, rightly understood, constitutes a moral good and that the love of others serves as an important principle in the political economy. We find less agreement in section two regarding justice and rights, but even here, we discover a few surprises. Both traditions uphold justice (giving to each party what is due) as essential to the political economy, and recognize some similarity in that type of justice called commutative. We note, however, substantial differences regarding a second type of justice that we call public justice. First, they differ over the extent to which government should be involved. Here the meaning of rights, especially that of individual freedom, arises. Secondly, the traditions diverge over whether benevolence as a motivator ought to serve as a partner for public justice. Thirdly, CEL in general opposes CST\u27s emphasis on social justice that calls upon institutions to be proactive in helping citizens and groups to become active participants in the economy. We conclude our essay by summarizing our discoveries and by suggesting areas for further dialogue