8,489 research outputs found
Southern Disclosure: One Southern-and-Queer Middle School Teacher’s Narrative
This narrative inquiry is an autoethnographical account of one queer-identified middle school teacher\u27s career trajectory in the southern United States, and his struggle to navigate disclosure of his identity to students. Using a qualitative lens, the authors provide reasoning for the importance of middle school educators to have the ability to disclose their identities to students in order to cultivate an environment that is receptive to LGBTQ+ adolescents
Phase diagram of the three-dimensional Anderson model of localization with random hopping
We examine the localization properties of the three-dimensional (3D) Anderson
Hamiltonian with off-diagonal disorder using the transfer-matrix method (TMM)
and finite-size scaling (FSS). The nearest-neighbor hopping elements are chosen
randomly according to . We find that the
off-diagonal disorder is not strong enough to localize all states in the
spectrum in contradistinction to the usual case of diagonal disorder. Thus for
any off-diagonal disorder, there exist extended states and, consequently, the
TMM converges very slowly. From the TMM results we compute critical exponents
of the metal-insulator transitions (MIT), the mobility edge , and study
the energy-disorder phase diagram.Comment: 4 pages, 5 EPS figures, uses annalen.cls style [included]; presented
at Localization 1999, to appear in Annalen der Physik [supplement
Earnings of Black and White Youth and Their Relation to Poverty
This paper examines the relation between youth employment and poverty for black and white families. An increase in the employment proportions of black men ages 16–19, which have lagged far behind their white counterparts, would reduce poverty among blacks to a moderate but meaningful degree. We provide evidence of a small positive feedback relation between black youth employment and family incomes that would magnify gains in both variables if either variable were increased. We also provide evidence that improvements in labor market conditions that affect youth employment, in the educational attainments of black youth, and in other policy-related variables would raise both youth employment and their family incomes.
Cumulative prospect theory and gambling
Whilst Cumulative Prospect theory (CPT) provides an explanation of gambling on longshots at actuarially unfair odds, it cannot explain why people might bet on more favoured outcomes. This paper shows that this is explicable if the degree of loss aversion experienced by the agent is reduced for small-stake gambles (as a proportion of wealth), and probability distortions are greater over losses than gains. If the utility or value function is assumed to be bounded, the degree of loss aversion assumed by Kahneman and Tversky leads to absurd predictions, reminiscent of those pointed out by Rabin (2000), of refusal to accept infinite gain bets at low probabilities. Boundedness of the value function in CPT implies that the indifference curve between expected-return and win-probability will typically exhibit both an asymptote (implying rejection of an infinite gain bet) and a minimum at low probabilities, as the shape of the value function dominates the probability weighting function. Also the high probability section of the indifference curve will exhibit a maximum. These implications are consistent with outcomes observed in gambling markets.
Projection-based image registration in the presence of fixed-pattern noise
A computationally efficient method for image registration is investigated that can achieve an improved performance over the traditional two-dimensional (2-D) cross-correlation-based techniques in the presence of both fixed-pattern and temporal noise. The method relies on transforming each image in the sequence of frames into two vector projections formed by accumulating pixel values along the rows and columns of the image. The vector projections corresponding to successive frames are in turn used to estimate the individual horizontal and vertical components of the shift by means of a one-dimensional (1-D) cross-correlation-based estimator. While gradient-based shift estimation techniques are computationally efficient, they often exhibit degraded performance under noisy conditions in comparison to cross-correlators due to the fact that the gradient operation amplifies noise. The projection-based estimator, on the other hand, significantly reduces the computational complexity associated with the 2-D operations involved in traditional correlation-based shift estimators while improving the performance in the presence of temporal and spatial noise. To show the noise rejection capability of the projection-based shift estimator relative to the 2-D cross correlator, a figure-of-merit is developed and computed reflecting the signal-to-noise ratio (SNR) associated with each estimator. The two methods are also compared by means of computer simulation and tests using real image sequences
Automatic presentations for semigroups
Special Issue: 2nd International Conference on Language and Automata Theory and Applications (LATA 2008)This paper applies the concept of FA-presentable structures to semigroups. We give a complete classification of the finitely generated FA-presentable cancellative semigroups: namely, a finitely generated cancellative semigroup is FA-presentable if and only if it is a subsemigroup of a virtually abelian group. We prove that all finitely generated commutative semigroups are FA-presentable. We give a complete list of FA-presentable one-relation semigroups and compare the classes of FA-presentable semigroups and automatic semigroups. (C) 2009 Elsevier Inc. All rights reserved.PostprintPeer reviewe
A global magnetic anomaly map
A subset of POGO satellite magnetometer data has been formed that is suitable for analysis of crustal magnetic anomalies. Using a thirteenth order field model, fit to these data, magnetic residuals have been calculated over the world to latitude limits of plus 50 deg. These residuals averaged over one degree latitude-longitude blocks represent a detailed global magnetic anomaly map derived solely from satellite data. Preliminary analysis of the map indicates that the anomalies are real and of geological origin
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