885 research outputs found
Introduction to Library Trends 55 (3) Winter 2007: Libraries in Times of War, Revolution and Social Change
published or submitted for publicatio
Enskog Theory for Polydisperse Granular Mixtures II. Sonine Polynomial Approximation
The linear integral equations defining the Navier-Stokes (NS) transport
coefficients for polydisperse granular mixtures of smooth inelastic hard disks
or spheres are solved by using the leading terms in a Sonine polynomial
expansion. Explicit expressions for all the NS transport coefficients are given
in terms of the sizes, masses, compositions, density and restitution
coefficients. In addition, the cooling rate is also evaluated to first order in
the gradients. The results hold for arbitrary degree of inelasticity and are
not limited to specific values of the parameters of the mixture. Finally, a
detailed comparison between the derivation of the current theory and previous
theories for mixtures is made, with attention paid to the implication of the
various treatments employed to date.Comment: 26 pages, to be published in Phys. Rev.
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Physical interpretation of the correlation between multi-angle spectral data and canopy height
Recent empirical studies have shown that multi-angle spectral data can be useful for predicting canopy height, but the physical reason for this correlation was not understood. We follow the concept of canopy spectral invariants, specifically escape probability, to gain insight into the observed correlation. Airborne Multi-Angle Imaging Spectrometer (AirMISR) and airborne Laser Vegetation Imaging Sensor (LVIS) data acquired during a NASA Terrestrial Ecology Program aircraft campaign underlie our analysis. Two multivariate linear regression models were developed to estimate LVIS height measures from 28 AirMISR multi-angle spectral reflectances and from the spectrally invariant escape probability at 7 AirMISR view angles. Both models achieved nearly the same accuracy, suggesting that canopy spectral invariant theory can explain the observed correlation. We hypothesize that the escape probability is sensitive to the aspect ratio (crown diameter to crown height). The multi-angle spectral data alone therefore may not provide enough information to retrieve canopy height globally
Patterns and outcomes of preterm hospital admissions during pregnancy in NSW, 2001-2008
Contains fulltext :
139362.pdf (publisher's version ) (Open Access
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Exploring the Neural Correlates of Social Stereotyping
Judging people on the basis of cultural stereotypes is a ubiquitous facet of daily life, yet little is known about how this fundamental inferential strategy is implemented in the brain. Using fMRI, we measured neural activity while participants made judgments about the likely actor (i.e., person-focus) and location (i.e., place-focus) of a series of activities, some of which were associated with prevailing gender stereotypes. Results revealed that stereotyping was underpinned by activity in areas associated with evaluative processing (e.g., ventral medial prefrontal cortex, amygdala) and the representation of action knowledge (e.g., supramarginal gyrus, middle temporal gyrus). In addition, activity accompanying stereotypic judgments was correlated with the strength of participants' explicit and implicit gender stereotypes. These findings elucidate how stereotyping fits within the neuroscience of person understanding.Psycholog
Enskog Theory for Polydisperse Granular Mixtures. I. Navier-Stokes order Transport
A hydrodynamic description for an -component mixture of inelastic, smooth
hard disks (two dimensions) or spheres (three dimensions) is derived based on
the revised Enskog theory for the single-particle velocity distribution
functions. In this first portion of the two-part series, the macroscopic
balance equations for mass, momentum, and energy are derived. Constitutive
equations are calculated from exact expressions for the fluxes by a
Chapman-Enskog expansion carried out to first order in spatial gradients,
thereby resulting in a Navier-Stokes order theory. Within this context of small
gradients, the theory is applicable to a wide range of restitution coefficients
and densities. The resulting integral-differential equations for the zeroth-
and first-order approximations of the distribution functions are given in exact
form. An approximate solution to these equations is required for practical
purposes in order to cast the constitutive quantities as algebraic functions of
the macroscopic variables; this task is described in the companion paper.Comment: 36 pages, to be published in Phys. Rev.
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