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The Texas Miracle: Racial Discrimination Alive and Well Sixty Years after Brown
The purpose of this study is to determine whether or not and how race plays a role in the funding of Texas public school districts. Beyond these determinations, we explore the legal implications that would come from evidence of a discriminatory funding system, specifically in light of Title VI of the Civil Rights Act. In this study, we use both quantitative and legal analysis. We explore population-level data containing information on the funding and racial composition of all Texas public school districts. Descriptive methods such as cross-tabulations were paired with correlation and measures of effect size to explore the relationship between race and school district funding. In our legal analysis, we review relevant legal statutes and case law, situating our quantitative findings within the larger, school finance jurisprudence context.Educatio
Non-destructive spatial heterodyne imaging of cold atoms
We demonstrate a new method for non-destructive imaging of laser-cooled
atoms. This spatial heterodyne technique forms a phase image by interfering a
strong carrier laser beam with a weak probe beam that passes through the cold
atom cloud. The figure of merit equals or exceeds that of phase-contrast
imaging, and the technique can be used over a wider range of spatial scales. We
show images of a dark spot MOT taken with imaging fluences as low as 61 pJ/cm^2
at a detuning of 11 linewidths, resulting in 0.0004 photons scattered per atom.Comment: text+3 figures, submitted to Optics Letter
Dynamics and statistical mechanics of ultra-cold Bose gases using c-field techniques
We review phase space techniques based on the Wigner representation that
provide an approximate description of dilute ultra-cold Bose gases. In this
approach the quantum field evolution can be represented using equations of
motion of a similar form to the Gross-Pitaevskii equation but with stochastic
modifications that include quantum effects in a controlled degree of
approximation. These techniques provide a practical quantitative description of
both equilibrium and dynamical properties of Bose gas systems. We develop
versions of the formalism appropriate at zero temperature, where quantum
fluctuations can be important, and at finite temperature where thermal
fluctuations dominate. The numerical techniques necessary for implementing the
formalism are discussed in detail, together with methods for extracting
observables of interest. Numerous applications to a wide range of phenomena are
presented.Comment: 110 pages, 32 figures. Updated to address referee comments. To appear
in Advances in Physic
Classical Region of a Trapped Bose Gas
The classical region of a Bose gas consists of all single-particle modes that
have a high average occupation and are well-described by a classical field.
Highly-occupied modes only occur in massive Bose gases at ultra-cold
temperatures, in contrast to the photon case where there are highly-occupied
modes at all temperatures. For the Bose gas the number of these modes is
dependent on the temperature, the total number of particles and their
interaction strength. In this paper we characterize the classical region of a
harmonically trapped Bose gas over a wide parameter regime. We use a
Hartree-Fock approach to account for the effects of interactions, which we
observe to significantly change the classical region as compared to the
idealized case. We compare our results to full classical field calculations and
show that the Hartree-Fock approach provides a qualitatively accurate
description of classical region for the interacting gas.Comment: 6 pages, 5 figures; updated to include new results with interaction
Cyber Bullying and Free Speech: Striking an Age-Appropriate Balance
Cyber bullying has generally been dealt with by the courts using one of two legal analyses: the “true threats” doctrine, or the Tinker substantial disruption test. This law review, the Cleveland State Law Review, recently published Anti-Cyber Bullying Statutes: Threat to Student Free Speech (referred to herein as “the Threat to Speech article”), which addressed these two theories, and argued that the current evolution of cyber bullying legislation simply goes too far. For example, Hayward states Anti-cyber bullying laws are the greatest threat to student speech because they seek to censor it anytime it occurs, using “substantial disruption” of school activities as justification and often based only on mere suspicion of potential disruption. The Threat to Speech article advocates greater protection of student speech. While we recognize that any regulation of speech by the state may raise First Amendment concerns, we are not so quick to conclude that cyber bullying regulations “chill student free speech.” Our analysis of the law leads us to the conclusion that school administrators have relatively broad discretion to regulate student speech, provided those regulations either serve legitimate pedagogical ends or protect the rights of other students and the school environment. Indeed, as we will demonstrate below, the evolution of the Supreme Court’s student free speech jurisprudence has followed the trend of granting more and more leeway to administrators. Contrary to the claims in the Threat to Speech article, in our opinion that leeway clearly extends to allowing regulation of speech which originates off campus but has a reasonable likelihood of making its way on campus. We also believe that, in addition to true threats and the Tinker substantial disruption standard described in the Threat to Speech article, school administrators may also regulate student speech consistent with the Court’s holding in Fraser—which set what we refer to as the “fundamental values standard” —and based on the fighting words doctrine
Constitutional Implications of School Punishment for Cyber Bullying
In this article, we address the scope of student free speech rights as it relates to cyber bullying. We provide a review of legal theories under which school administrators can address cyber bullying while still respecting student free speech rights and the First Amendment. Additionally, we address the jurisdiction of administrators to deal with off-campus bullying conduct
Cyber Bullying and Free Speech: Striking an Age-Appropriate Balance
Cyber bullying has generally been dealt with by the courts using one of two legal analyses: the “true threats” doctrine, or the Tinker substantial disruption test. This law review, the Cleveland State Law Review, recently published Anti-Cyber Bullying Statutes: Threat to Student Free Speech (referred to herein as “the Threat to Speech article”), which addressed these two theories, and argued that the current evolution of cyber bullying legislation simply goes too far. For example, Hayward states Anti-cyber bullying laws are the greatest threat to student speech because they seek to censor it anytime it occurs, using “substantial disruption” of school activities as justification and often based only on mere suspicion of potential disruption. The Threat to Speech article advocates greater protection of student speech. While we recognize that any regulation of speech by the state may raise First Amendment concerns, we are not so quick to conclude that cyber bullying regulations “chill student free speech.” Our analysis of the law leads us to the conclusion that school administrators have relatively broad discretion to regulate student speech, provided those regulations either serve legitimate pedagogical ends or protect the rights of other students and the school environment. Indeed, as we will demonstrate below, the evolution of the Supreme Court’s student free speech jurisprudence has followed the trend of granting more and more leeway to administrators. Contrary to the claims in the Threat to Speech article, in our opinion that leeway clearly extends to allowing regulation of speech which originates off campus but has a reasonable likelihood of making its way on campus. We also believe that, in addition to true threats and the Tinker substantial disruption standard described in the Threat to Speech article, school administrators may also regulate student speech consistent with the Court’s holding in Fraser—which set what we refer to as the “fundamental values standard” —and based on the fighting words doctrine
Wetland Bird Abundance and Safety Implications for Military Aircraft Operations
Wetlands with associated avifauna can pose a substantial hazard to aviation safety, potentially increasing bird–aircraft collision (strike) risk when located near air operations areas.We modeled year-round use by wetland avifauna of Drummond Flats Wildlife Management Area (Drummond Flats), a wetland complex located within 10 km of Vance Air Force Base (AFB), Enid, Oklahoma, USA. Our objectives were to 1) quantify seasonal avifauna abundances at Drummond Flats; 2) test a priori models reflecting use by bird species recognized as hazardous to aviation safety relative to environmental factors including flooded wetland habitat and vegetation cover; 3) use these models to predict maximal expected abundances of wetland avifauna during flood conditions; and 4) compare our findings with reported bird strikes at Vance AFB. Drought conditions influenced avian use during our study. Of the species expected to respond predictably to flooded wetland habitat, only ducks (Anatinae) occurred in numbers conducive to modeling. Using zeroinflated Poisson models, we found that duck abundance was positively associated with permanent wetland habitat type and, excluding winter, available habitat area (i.e., standing water); whereas, \u3e50% vegetation cover was negatively correlated with abundance. No model predicted \u3e97.2 ducks/ha for any habitat type, except during winter. Our models also identified potential peaks in abundance not evident from raw count data, emphasizing the benefits of this approach. Identifying factors driving abundances also enables targeted management of hazardous species. Further, we found double-sampling to be a practical method for assessing detection bias during avian surveys at wetlands. Restricting to obligate wetland species associated with Drummond Flats, we found 1 strike/184,212 flight-hours, which was an order of magnitude lower than the average for U.S. civil aircraft (1990–2014). Thus, under drought conditions, bird use of Drummond Flats likely did not elevate strike risk for Vance AFB aircraft operations. Published 2017. This article is a U.S. Government work and is in the public domain in the US
Bose-Einstein Condensation from a Rotating Thermal Cloud: Vortex Nucleation and Lattice Formation
We develop a stochastic Gross-Pitaveskii theory suitable for the study of
Bose-Einstein condensation in a {\em rotating} dilute Bose gas. The theory is
used to model the dynamical and equilibrium properties of a rapidly rotating
Bose gas quenched through the critical point for condensation, as in the
experiment of Haljan et al. [Phys. Rev. Lett., 87, 21043 (2001)]. In contrast
to stirring a vortex-free condensate, where topological constraints require
that vortices enter from the edge of the condensate, we find that phase defects
in the initial non-condensed cloud are trapped en masse in the emerging
condensate. Bose-stimulated condensate growth proceeds into a disordered vortex
configuration. At sufficiently low temperature the vortices then order into a
regular Abrikosov lattice in thermal equilibrium with the rotating cloud. We
calculate the effect of thermal fluctuations on vortex ordering in the final
gas at different temperatures, and find that the BEC transition is accompanied
by lattice melting associated with diminishing long range correlations between
vortices across the system.Comment: 15 pages, 12 figure
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