49,326 research outputs found
Dynamics of Perturbed Relative Equilibria of Point Vortices on the Sphere or Plane
Stable assemblages of localized vortices exist which have particle-like
properties, such as mass, and which can interact with one another when they
closely approach. In this article I calculate the mass of these localized
states and numerically investigate some aspects of their interactions.Comment: 14 pages, 3 figure
Reduction of the planar 4-vortex system at zero momentum
The system of four point vortices in the plane has relative equilibria that
behave as composite particles, in the case where three of the vortices have
strength and one of the vortices has strength . These
relative equilibria occur at nongeneric momenta. The reduction of this system,
at those momenta, by continuous and then discrete symmetries, classifies the
4-vortex states which have been observed as products of collisions of two such
composite particles. In this article I explicitly calculate these reductions,
and show they are qualitatively identical one degree of freedom systems on a
cylinder. The flows on these reduced systems all have one stable equilibrium
and one unstable equilibrium, and all the orbits are periodic except for two
homoclinic connections to the unstable equilibrium.Comment: Minor typographical corrections and slightly revised introduction. 9
pages, 5 figures. To appear EQUIDIFF/99 proceeding
Preventing recidivism by using the theory of reintegrative shaming with conferences
Master's Project (M.A.) University of Alaska Fairbanks, 2013Driving while intoxicated in the United States is a major problem with more than 31 percent of national driving fatalities caused by intoxicated drivers. The purpose of the present study is to identify the possibility between the use of reintegrative shaming with conferences and the likelihood that it will reduce the recidivism of driving while intoxicated. The study explores John Brathwaite's theory on reintegrative shaming and how that theory applies in conferences. The emerging theory o f Storylines from Robert Agnew is also explored in its importance when conducting these conferences. Studies conducted in Australia, Pennsylvania, Kansas and Alaska have all suggested that the use of conferences, especially those which utilize reintegrative shaming and reintegrating offenders back into the community reduces the recidivism rates. The research found in this article helps point future studies to examine offenders in a longer term after they have completed reintegrative shaming programs and conferences
Thermal Geo-axions
We estimate the production rate of axion-type particles in the core of the
Earth, at a temperature T~5000K. We constrain thermal geo-axion emission by
demanding a core-cooling rate less than 100K/Gyr, as suggested by geophysics.
This yields a "quasi-vacuum" (unaffected by extreme stellar conditions) bound
on the axion-electron fine structure constant \alpha_a^{QV} < 10^{-18},
stronger than the existing accelerator (vacuum) bound by 4 orders of magnitude.
We consider the prospects for measuring the geo-axion flux through conversion
into photons in a geoscope; such measurements can further constrain
\alpha_a^{QV}.Comment: 4 pages, 1 figur
Skew critical problems
Skew critical problems occur in continuous and discrete nonholonomic
Lagrangian systems. They are analogues of constrained optimization problems,
where the objective is differentiated in directions given by an apriori
distribution, instead of tangent directions to the constraint. We show
semiglobal existence and uniqueness for nondegenerate skew critical problems,
and show that the solutions of two skew critical problems have the same contact
as the problems themselves. Also, we develop some infrastructure that is
necessary to compute with contact order geometrically, directly on manifolds
The Economic Benefits of Closing Educational Achievement Gaps: Promoting Growth and Strengthening the Nation by Improving the Educational Outcomes of Children of Color
This report quantifies the economic benefits of closing one of the most harmful racial and ethnic gaps: the educational achievement gap that exists between black and Hispanic children and native-born white children. Gaps in academic achievement are a function of a host of factors, such as income and wealth inequality, access to child care and preschool programs, nutrition, physical and emotional health, environmental factors, community and family structures,differences in the quality of instruction and school, and educational attainment. This suggests there are a wide range of public policies that could help narrow educational achievement gaps; this report demonstrates that there are enormous payoffs to closing the gaps through public policies. It also outlines effective public policy strategies to achieve this goal, though their details are left to future research. After briefly summarizing the analysis's findings, this report places the educational achievement gaps in context to help explain their significance and the reasons they exist. In particular, the report reviews data on growing inequality, demographic changes, and intensifying global economic competition. This clarifies the need to address educational achievement gaps and helps explain why the benefits of closing gaps are great. The report then describes factors that cause educational achievement gaps and offers public policies that could help close them. The subsequent sections of the report discuss the literature on the importance of academic achievement to economic growth, the methodology used in the analysis, and its detailed findings
Letter from Patrick G. Halpin, New York State Assembly Member, to Geraldine Ferraro
Letter of support from New York state assembly member Patrick G. Halpin to Geraldine Ferraro. Contains standard response from Ferraro.https://ir.lawnet.fordham.edu/vice_presidential_campaign_correspondence_1984_new_york/1018/thumbnail.jp
Interdependence of science requirements and safety limitations on the space station
One of the benefits of experimentation on the Space Station is the ability to carry out the experiment, to immediately analyze the results, to calculate improved experimental parameters, and to quickly repeat the experiment. In this improved mode of operation there are new safety considerations that must be addressed in the design stages of both the station and the experiments. Some of the chemical and procedural requirements are shared, and some of the earth-bound storage, dispensing, and disposal techniques that may assist in the development of analogous procedures for the Space Station are discussed
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