39,553 research outputs found
A Shplit Ticket, Half Irish, Half Chinay : Representations of Mixed-Race and Hybridity in the Turn-of-the-Century Theater
Charles Townsend\u27s 1889 adaptation of Harriet Beecher Stowe\u27s Uncle Tom\u27s Cabin features white actors playing light- and dark-skinned African-American characters, changing degrees of make-up as the script, stage business, or number of available players demands. Thomas Denison\u27s stage directions to his 1895 play, Patsy O\u27Wang, an Irish Farce with a Chinese Mix-Up, stipulates that the alternation of the half -Chinese, half-Irish cook between his two ethnic personas is key to this capital farce, and that a comedie use of the Chinese dialect is central to this. The Geezer (c. 1896), Joseph Herbert\u27s spoof of the popular musical, The Geisha, features white actors playing Chinese dignitaries, but also donning German and Irish accents. The white actors in these plays enact different paradigms of hybridity. The actors in Townsend\u27s Uncle Tom\u27s Cabin, a Melodrama in Five Acts embody conceptions of both mixed and unmixed African Americans, freely alternating between each. In Patsy O\u27Wang, the main character\u27s background is central to the story, and the lead actor moves between the two ethnicities by his accent, mannerisms, and politics. Racial mixing is central to the plot of The Geezer through Anglo actors who make themselves hybrid by appearing Chinese and appropriating a third accent, rather than the creation of racially mixed offspring
Intermittent turbulence and turbulent structures in a linear magnetized plasma
Strongly intermittent turbulence is observed in the shadow of a limiter in
the Large Plasma Device (LAPD) at UCLA [W. Gekelman, H. Pfister, Z. Lucky, J.
Bamber, D. Leneman, and J. Maggs, Rev. Sci. Inst. {\bfseries 62}, 2875 (1991)].
The amplitude probability distribution function (PDF) of the turbulence is
strongly skewed, with density depletion events (or ``holes'') dominant in the
high density region and density enhancement events (or ``blobs'') dominant in
the low density region. Two-dimensional cross-conditional averaging shows that
the blobs are detached, outward-propagating filamentary structures with a clear
dipolar potential while the holes appear to be part of a more extended
turbulent structure. A statistical study of the blobs reveals a typical size of
ten times the ion sound gyroradius and a typical velocity of one tenth the
sound speed.Comment: 12 pages, 4 figures, to appear in Physics of Plasma
Fuel optimal maneuvers of spacecraft about a circular orbit
Fuel optimal maneuvers of spacecraft relative to a body in circular orbit are investigated using a point mass model in which the magnitude of the thrust vector is bounded. All nonsingular optimal maneuvers consist of intervals of full thrust and coast and are found to contain at most seven such intervals in one period. Only four boundary conditions where singular solutions occur are possible. Computer simulation of optimal flight path shapes and switching functions are found for various boundary conditions. Emphasis is placed on the problem of soft rendezvous with a body in circular orbit
Social Network Analysis with sna
Modern social network analysis---the analysis of relational data arising from social systems---is a computationally intensive area of research. Here, we provide an overview of a software package which provides support for a range of network analytic functionality within the R statistical computing environment. General categories of currently supported functionality are described, and brief examples of package syntax and usage are shown.
network: A Package for Managing Relational Data in R
Effective memory structures for relational data within R must be capable of representing a wide range of data while keeping overhead to a minimum. The network package provides an class which may be used for encoding complex relational structures composed a vertex set together with any combination of undirected/directed, valued/unvalued, dyadic/hyper, and single/multiple edges; storage requirements are on the order of the number of edges involved. Some simple constructor, interface, and visualization functions are provided, as well as a set of operators to facilitate employment by end users. The package also supports a C-language API, which allows developers to work directly with network objects within backend code.
Graphene valley filter using a line defect
With its two degenerate valleys at the Fermi level, the band structure of
graphene provides the opportunity to develop unconventional electronic
applications. Herein, we show that electron and hole quasiparticles in graphene
can be filtered according to which valley they occupy without the need to
introduce confinement. The proposed valley filter is based on scattering off a
recently observed line defect in graphene. Quantum transport calculations show
that the line defect is semitransparent and that quasiparticles arriving at the
line defect with a high angle of incidence are transmitted with a valley
polarization near 100%.Comment: 5 pages, 4 figure
Valley and spin polarization from graphene line defect scattering
Quantum transport calculations describing electron scattering off an extended
line defect in graphene are presented. The calculations include potentials from
local magnetic moments recently predicted to exist on sites adjacent to the
line defect. The transmission probability is derived and expressed as a
function of valley, spin, and angle of incidence of an electron at the Fermi
level being scattered. It is shown that the previously predicted valley
polarization in a beam of transmitted electrons is not significantly influenced
by the presence of the magnetic moments. These moments, however, do introduce
some spin polarization, in addition to the valley polarization, albeit no more
than about 20%.Comment: 6 pages, 4 figure
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