78,608 research outputs found
Life after Welfare: The Economic Well-Being of Women and Children Following an Exit from AFDC
Much previous research has focused on the length of welfare spells and returns to welfare following an exit. Few quantitative studies have looked at broader indicators of the economic well-being of those who have exited AFDC. In this paper we use data from the National Longitudinal Survey of Youth (NSLY) to trace welfare use, poverty status, and primary sources of income in the five years following an exit from welfare. We find that while there is a trend toward improved economic status over time, 40 percent of women remain poor five years after exit. Women with more advantaged family backgrounds, those with fewer children, or with more education at exit are more likely to consistently escape poverty. Median income increases over the first five years from about 15,000 (1992 dollars). Own earnings are the most prevalent income source, followed by spouse's earnings, and mean-tested transfers.
Cross Calibration of Imaging Air Cherenkov Telescopes with Fermi
An updated model for the synchrotron and inverse Compton emission from a
population of high energy electrons of the Crab Nebula is used to reproduce the
measured spectral energy distribution from radio to high energy gamma-rays. By
comparing the predicted inverse Compton component with recent Fermi
measurements of the nebula's emission, it is possible to determine the average
magnetic field in the nebula and to derive the underlying electron energy
distribution. The model calculation can then be used to cross calibrate the
Fermi observations with ground based air shower measurements. The resulting
energy calibration factors are derived and can be used for combining broad
energy measurements taken with Fermi in conjunction with ground based
measurements.Comment: 2009 Fermi Symposium, eConf Proceedings C091122, 5 pages, 5 figures,
3 table
Life prediction and constitutive models for engine hot section anisotropic materials program
This report presents the results from a 35 month period of a program designed to develop generic constitutive and life prediction approaches and models for nickel-based single crystal gas turbine airfoils. The program is composed of a base program and an optional program. The base program addresses the high temperature coated single crystal regime above the airfoil root platform. The optional program investigates the low temperature uncoated single crystal regime below the airfoil root platform including the notched conditions of the airfoil attachment. Both base and option programs involve experimental and analytical efforts. Results from uniaxial constitutive and fatigue life experiments of coated and uncoated PWA 1480 single crystal material form the basis for the analytical modeling effort. Four single crystal primary orientations were used in the experiments: (001), (011), (111), and (213). Specific secondary orientations were also selected for the notched experiments in the optional program. Constitutive models for an overlay coating and PWA 1480 single crystal material were developed based on isothermal hysteresis loop data and verified using thermomechanical (TMF) hysteresis loop data. A fatigue life approach and life models were selected for TMF crack initiation of coated PWA 1480. An initial life model used to correlate smooth and notched fatigue data obtained in the option program shows promise. Computer software incorporating the overlay coating and PWA 1480 constitutive models was developed
TOPEX satellite concept. TOPEX option study report
Candidate bus equipment from the Viking, Applications Explorer Mission, and Small Scientific Satellite programs for application to the TOPEX mission options is assessed. Propulsion module equipment and subsystem candidates from the Applications Explorer Mission satellites and the Small Scientific Satellite spacecraft are evaluated for those TOPEX options. Several subsystem concepts appropriate to the TOPEX options are described. These descriptions consider performance characteristics of the subsystems. Cost and availability information on the candidate equipment and subsystems are also provided
Binding between two-component bosons in one dimension
We investigate the ground state of one-dimensional few-atom Bose-Bose
mixtures under harmonic confinement throughout the crossover from weak to
strong inter-species attraction. The calculations are based on the numerically
exact multi-configurational time-dependent Hartree method. For repulsive
components we detail the condition for the formation of a molecular
Tonks-Girardeau gas in the regime of intermediate inter-species interactions,
and the formation of a molecular condensate for stronger coupling. Beyond a
critical inter-species attraction, the system collapses to an overall bound
state. Different pathways emerge for unequal particle numbers and intra-species
interactions. In particular, for mixtures with one attractive component, this
species can be viewed as an effective potential dimple in the trap center for
the other, repulsive component.Comment: 10 pages, 10 figure
Quantum Chinos Game: winning strategies through quantum fluctuations
We apply several quantization schemes to simple versions of the Chinos game.
Classically, for two players with one coin each, there is a symmetric stable
strategy that allows each player to win half of the times on average. A partial
quantization of the game (semiclassical) allows us to find a winning strategy
for the second player, but it is unstable w.r.t. the classical strategy.
However, in a fully quantum version of the game we find a winning strategy for
the first player that is optimal: the symmetric classical situation is broken
at the quantum level.Comment: REVTEX4.b4 file, 3 table
Localization of Two-Dimensional Quantum Walks
The Grover walk, which is related to the Grover's search algorithm on a
quantum computer, is one of the typical discrete time quantum walks. However, a
localization of the two-dimensional Grover walk starting from a fixed point is
striking different from other types of quantum walks. The present paper
explains the reason why the walker who moves according to the degree-four
Grover's operator can remain at the starting point with a high probability. It
is shown that the key factor for the localization is due to the degeneration of
eigenvalues of the time evolution operator. In fact, the global time evolution
of the quantum walk on a large lattice is mainly determined by the degree of
degeneration. The dependence of the localization on the initial state is also
considered by calculating the wave function analytically.Comment: 21 pages RevTeX, 4 figures ep
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