5,532 research outputs found
Policy Support Within a Target Group: The Case of School Desegregation
This study empirically tests three theoretical approaches to explaining specific support for a policy output among members of its target group. The utilitarian model posits support as a function of objective costs and benefits to the individual stemming directly from the policy. The attitudinal model relates specific support to diffuse predispositions rooted in socialization. The perceptual model holds that specific support derives from beliefs about the character of the political decision process by which the policy was formulated. Tests of these three approaches are based on survey data on specific support for school district desegregation plans among a large sample of black and white parents of public school children in Florida. In both subsamples, the utilitarian approach explained very little of the variance in support, but the attitudinal and perceptual models were corroborated. Implications of these findings are drawn for desegregation policy making and for public policy theory
Policy Support Within a Target Group: The Case of School Desegregation
This study empirically tests three theoretical approaches to explaining specific support for a policy output among members of its target group. The utilitarian model posits support as a function of objective costs and benefits to the individual stemming directly from the policy. The attitudinal model relates specific support to diffuse predispositions rooted in socialization. The perceptual model holds that specific support derives from beliefs about the character of the political decision process by which the policy was formulated. Tests of these three approaches are based on survey data on specific support for school district desegregation plans among a large sample of black and white parents of public school children in Florida. In both subsamples, the utilitarian approach explained very little of the variance in support, but the attitudinal and perceptual models were corroborated. Implications of these findings are drawn for desegregation policy making and for public policy theory
A GPU-based survey for millisecond radio transients using ARTEMIS
Astrophysical radio transients are excellent probes of extreme physical
processes originating from compact sources within our Galaxy and beyond. Radio
frequency signals emitted from these objects provide a means to study the
intervening medium through which they travel. Next generation radio telescopes
are designed to explore the vast unexplored parameter space of high time
resolution astronomy, but require High Performance Computing (HPC) solutions to
process the enormous volumes of data that are produced by these telescopes. We
have developed a combined software /hardware solution (code named ARTEMIS) for
real-time searches for millisecond radio transients, which uses GPU technology
to remove interstellar dispersion and detect millisecond radio bursts from
astronomical sources in real-time. Here we present an introduction to ARTEMIS.
We give a brief overview of the software pipeline, then focus specifically on
the intricacies of performing incoherent de-dispersion. We present results from
two brute-force algorithms. The first is a GPU based algorithm, designed to
exploit the L1 cache of the NVIDIA Fermi GPU. Our second algorithm is CPU based
and exploits the new AVX units in Intel Sandy Bridge CPUs.Comment: 4 pages, 7 figures. To appear in the proceedings of ADASS XXI, ed.
P.Ballester and D.Egret, ASP Conf. Se
A rigid body model for the assessment of glenohumeral joint mechanics: Influence of osseous defects on range of motion and dislocation
© 2016. The purpose of this study was to employ subject-specific computer models to evaluate the interaction of glenohumeral range-of-motion and Hill-Sachs humeral head bone defect size on engagement and shoulder dislocation. We hypothesized that the rate of engagement would increase as defect size increased, and that greater shoulder ROM would engage smaller defects. Three dimensional computer models of 12 shoulders were created. For each shoulder, additional models were created with simulated Hill-Sachs defects of varying severities (XS=15%, S=22.5%, M=30%, L=37.5%, XL=45% and XXL=52.5% of the humeral head diameter, respectively). Rotational motion simulations without translation were conducted. The simulations ended if the defect engaged the anterior glenoid rim with resultant dislocation. The results showed that the rate of engagement was significantly different between defect sizes (0.00
Anharmonic transitions in nearly dry L-cysteine I
Two special dynamical transitions of universal character have been recently
observed in macromolecules at K and K.
Despite their relevance, a complete understanding of the nature of these
transitions and their consequences for the bio-activity of the macromolecule is
still lacking. Our results and analysis concerning the temperature dependence
of structural, vibrational and thermodynamical properties of the orthorhombic
polymorph of the amino acid L-cysteine (at a hydration level of 3.5%) indicated
that the two referred temperatures define the triggering of very simple and
specific events that govern all the biochemical interactions of the
biomolecule: activation of rigid rotors (), phonon-phonon interactions
with phonons of water dimer (), and water rotational barriers
surpassing ().Comment: 4 pages, 4 figures, submitted to Physical Review Letter
Mathematical modeling of cell population dynamics in the colonic crypt and in colorectal cancer
Colorectal cancer is initiated in colonic crypts. A succession of genetic mutations or epigenetic changes can lead to homeostasis in the crypt being overcome, and subsequent unbounded growth. We consider the dynamics of a single colorectal crypt by using a compartmental approach [Tomlinson IPM, Bodmer WF (1995) Proc Natl Acad Sci USA 92: 11130-11134], which accounts for populations of stem cells, differential cells, and transit cells. That original model made the simplifying assumptions that each cell popuation divides synchronously, but we relax these assumptions by adopting an age-structured approach that models asynchronous cell division, and by using a continuum model. We discuss two mechanims that could regulate the growth of cell numbers and maintain the equilibrium that is normally observed in the crypt. The first will always maintain an equilibrium for all parameter values, whereas the second can allow unbounded proliferation if the net per capita growth rates are large enough. Results show that an increase in cell renewal, which is equivalent to a failure of programmed cell death or of differentiation, can lead to the growth of cancers. The second model can be used to explain the long lag phases in tumor growth, during which news, higher equilibria are reached, before unlimited growth in cell number ensues
Magnetosheath High-Speed Jets: Internal Structure and InteractionWith Ambient Plasma
National Aeronautics and Space Administration (NASA). Grant Number: NNG04EB99C; Österreichische Forschungsförderungsgesellschaft (FFG); Austrian Academy of Sciences and the Austrian Space Applications Programme. Grant Number: FFG/ASAP-844377; NASA. Grant Numbers: NNX17AI45G, NAS5-02099; Austrian Science Fund (FWF). Grant Number: P 28764-N2
Lidar System Model for Use With Path Obscurants and Experimental Validation
When lidar pulses travel through a short path that includes a relatively high concentration of aerosols, scattering phenomena can alter the power and temporal properties of the pulses significantly, causing undesirable effects in the received pulse. In many applications the design of the lidar transmitter and receiver must consider adverse environmental aerosol conditions to ensure the desired performance. We present an analytical model of lidar system operation when the optical path includes aerosols for use in support of instrument design, simulations, and system evaluation. The model considers an optical path terminated with a solid object, although it can also be applied, with minor modifications, to cases where the expected backscatter occurs from nonsolid objects. The optical path aerosols are characterized by their attenuation and backscatter coefficients derived by the Mie theory from the concentration and particle size distribution of the aerosol. Other inputs include the lidar system parameters and instrument response function, and the model output is the time-resolved received pulse. The model is demonstrated and experimentally validated with military fog oil smoke for short ranges (several meters). The results are obtained with a lidar system operating at a wavelength of 0.905 μm within and outside the aerosol. The model goodness of fit is evaluated using the statistical coefficient of determination whose value ranged from 0.88 to 0.99 in this study
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