11,329 research outputs found
Book Review: Hewitt, Nancy A. Women\u27s Activism And Social Change: Rochester, New York, 1822-1872
Scholar Nancy A. Hewitt analyzes the lives of women in antebellum Rochester, New York, focusing how they adapted to a wide variety of changes during a turbulent period in American history
Data base for the Colorado profiling network
The Colorado profiling system developed by the Wave Propagation Laboratory (WPL) includes five (soon to be six) Doppler radar wind Profilers; four operate at 49 MHz (6 m) and are located at Platteville, Fleming, Lay Creek, and Cahone, and one operates at 915 MHz (33 cm) and is located at Denver. The sixth radar, now under construction, will operate at 405 MHz (UHF) and will be located at Boulder. Microwave radiometers and surface meteorological stations are at some of the radar sites. The data base for the wind Profilers is discussed
Time-Dependent Models for Dark Matter at the Galactic Center
The prospects of indirect detection of dark matter at the galactic center
depend sensitively on the mass profile within the inner parsec. We calculate
the distribution of dark matter on sub-parsec scales by integrating the
time-dependent Fokker-Planck equation, including the effects of
self-annihilations, scattering of dark matter particles by stars, and capture
in the supermassive black hole. We consider a variety of initial dark matter
distributions, including models with very high densities ("spikes") near the
black hole, and models with "adiabatic compression" of the baryons. The
annihilation signal after 10 Gyr is found to be substantially reduced from its
initial value, but in dark matter models with an initial spike,
order-of-magnitude enhancements can persist compared with the rate in
spike-free models, with important implications for indirect dark matter
searches with GLAST and Air Cherenkov Telescopes like HESS and CANGAROO.Comment: Four page
Three `species' of Schr\"odinger cat states in an infinite-range spin model
We explore a transverse-field Ising model that exhibits both spontaneous
symmetry-breaking and eigenstate thermalization. Within its ferromagnetic
phase, the exact eigenstates of the Hamiltonian of any large but finite-sized
system are all Schr\"odinger cat states: superpositions of states with `up' and
`down' spontaneous magnetization. This model exhibits two dynamical phase
transitions {\it within} its ferromagnetic phase: In the lowest-temperature
phase the magnetization can macroscopically oscillate between up and down. The
relaxation of the magnetization is always overdamped in the remainder of the
ferromagnetic phase, which is divided in to phases where the system thermally
activates itself {\it over} the barrier between the up and down states, and
where it quantum tunnels.Comment: 7 pages, added numerical result
Research on new techniques for the analysis of manual control systems Progress report, 16 Jun. - 15 Dec. 1968
Parameter estimation for continuous input-output systems with internal sampling in human controller model
Lessons from Fiascos in Russian Corporate Governance
"Bad corporate governance" is often invoked to explain poor enterprise performance, but the catch phrase is never precisely defined - neither its consequences for the real economy, nor its causes in particular countries has been adequately explained. This paper uses Russian enterprise examples to address these open questions in corporate governance theory. We define corporate governance by looking to the economic functions of the firm rather than to any particular set of national corporate laws. Firms exhibit good corporate governance when their managers maximize residuals and, in the case of investor-owned firms, make pro rata distributions to shareholders. First, using this definition, we develop a typology that shows the channels through which bad corporate governance can inflict damage on the real economy. The topology helps identify vulnerabilities to corporate governance problems that may appear in any country and it suggests a new way to tailor policy responses. Second, we explain the causes of poor corporate performance in Russia by looking to the particular conditions prevailing at privatization - untenable initial firm boundaries and insider allocation of firm shares - and the bargaining dynamics that followed. The focus on initial conditions helps expand a comparative corporate governance literature built on United States, Western European, and Japanese models. Lessons from Russian fiascos counsel caution as to "stakeholder" proposals - including labor or local communities in formal corporate governance - and generate testable hypotheses regarding potential losses from the multiple large block share ownerships typical of many U.S. firms, especially close corporations.
Black Hole Motion as Catalyst of Orbital Resonances
The motion of a black hole about the centre of gravity of its host galaxy
induces a strong response from the surrounding stellar population. We treat the
case of a harmonic potential analytically and show that half of the stars on
circular orbits in that potential shift to an orbit of lower energy, while the
other half receive a positive boost and recede to a larger radius. The black
hole itself remains on an orbit of fixed amplitude and merely acts as a
catalyst for the evolution of the stellar energy distribution function f(E). We
show that this effect is operative out to a radius of approx 3 to 4 times the
hole's influence radius, R_bh. We use numerical integration to explore more
fully the response of a stellar distribution to black hole motion. We consider
orbits in a logarithmic potential and compare the response of stars on circular
orbits, to the situation of a `warm' and `hot' (isotropic) stellar velocity
field. While features seen in density maps are now wiped out, the kinematic
signature of black hole motion still imprints the stellar line-of-sight mean
velocity to a magnitude ~18% the local root mean-square velocity dispersion
sigma.Comment: revised version, typos fixed, added references, 20 pages MN styl
Research on new techniques for the analysis of manual control systems Progress report, 15 Dec. 1968 - 15 Jun. 1969
Decision processes of human manual controllers, neuromuscular system, and stochastic processe
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