7,093 research outputs found
Comment on: Diffusion through a slab
Mahan [J. Math. Phys. 36, 6758 (1995)] has calculated the transmission
coefficient and angular distribution of particles which enter a thick slab at
normal incidence and which diffuse in the slab with linear anisotropic,
non-absorbing, scattering. Using orthogonality relations derived by McCormick &
Kuscer [J. Math. Phys. 6, 1939 (1965); 7, 2036 (1966)] for the eigenfunctions
of the problem, this calculation is generalised to a boundary condition with
particle input at arbitrary angles. It is also shown how to use the
orthogonality relations to relax in a simple way the restriction to a thick
slab.Comment: 3 pages, LaTeX, uses RevTe
Fast light, slow light, and phase singularities: a connection to generalized weak values
We demonstrate that Aharonov-Albert-Vaidman (AAV) weak values have a direct
relationship with the response function of a system, and have a much wider
range of applicability in both the classical and quantum domains than
previously thought. Using this idea, we have built an optical system, based on
a birefringent photonic crystal, with an infinite number of weak values. In
this system, the propagation speed of a polarized light pulse displays both
superluminal and slow light behavior with a sharp transition between the two
regimes. We show that this system's response possesses two-dimensional,
vortex-antivortex phase singularities. Important consequences for optical
signal processing are discussed.Comment: 9 pages, 4 figures, accepted in Physical Review Letters (2003
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Simulator for the Linear Collider (SLIC): a Tool for ILC Detector Simulations
The Simulator for the Linear Collider (SLIC) is a detector simulation program based on the GEANT4 toolkit. It is intended to enable end users to easily model detector concepts by providing the ability to fully describe detectors using plain text files read in by a common executable at runtime. The detector geometry, typically the most complex part of a detector simulation, is described at runtime using the Linear Collider Detector Description (LCDD). This system allows end users to create complex detector geometries in a standard XML format rather than procedural code such as C++. The LCDD system is based on the Geometry Description Markup Language (GDML) from the LHC Applications Group (LCG). The geometry system facilitates the study of different full detector design and their variations. SLIC uses the StdHep format to read input created by event generators and outputs events in the Linear Collider IO (LCIO) format. The SLIC package provides a binding to GEANT4 and many additional commands and features for the end user
Probing the subshell closure: factor of the Mg(2) state
The first-excited state ~factor of Mg has been measured relative to
the factor of the Mg() state using the high-velocity
transient-field technique, giving . This new measurement is in
strong disagreement with the currently adopted value, but in agreement with the
-shell model using the USDB interaction. The newly measured factor,
along with and systematics, signal the closure of the subshell at . The possibility that precise -factor
measurements may indicate the onset of neutron admixtures in first-excited
state even-even magnesium isotopes below Mg is discussed and the
importance of precise excited-state -factor measurements on ~shell
nuclei with to test shell-model wavefunctions is noted.Comment: 8 pages, 5 figure
Optimizing end-labeled free-solution electrophoresis by increasing the hydrodynamic friction of the drag-tag
We study the electrophoretic separation of polyelectrolytes of varying
lengths by means of end-labeled free-solution electrophoresis (ELFSE). A
coarse-grained molecular dynamics simulation model, using full electrostatic
interactions and a mesoscopic Lattice Boltzmann fluid to account for
hydrodynamic interactions, is used to characterize the drag coefficients of
different label types: linear and branched polymeric labels, as well as
transiently bound micelles.
It is specifically shown that the label's drag coefficient is determined by
its hydrodynamic size, and that the drag per label monomer is largest for
linear labels. However, the addition of side chains to a linear label offers
the possibility to increase the hydrodynamic size, and therefore the label
efficiency, without having to increase the linear length of the label, thereby
simplifying synthesis. The third class of labels investigated, transiently
bound micelles, seems very promising for the usage in ELFSE, as they provide a
significant higher hydrodynamic drag than the other label types.
The results are compared to theoretical predictions, and we investigate how
the efficiency of the ELFSE method can be improved by using smartly designed
drag-tags.Comment: 32 pages, 11 figures, submitted to Macromolecule
The zebrafish xenograft platform-A novel tool for modeling KSHV-associated diseases
Kaposi\u27s sarcoma associated-herpesvirus (KSHV, also known as human herpesvirus-8) is a gammaherpesvirus that establishes life-long infection in human B lymphocytes. KSHV infection is typically asymptomatic, but immunosuppression can predispose KSHV-infected individuals to primary effusion lymphoma (PEL); a malignancy driven by aberrant proliferation of latently infected B lymphocytes, and supported by pro-inflammatory cytokines and angiogenic factors produced by cells that succumb to lytic viral replication. Here, we report the development of the firs
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