46,494 research outputs found
An introduction to quantitative remote sensing
The quantitative approach to remote sensing is discussed along with the analysis of remote sensing data. Emphasis is placed on the application of pattern recognition in numerically oriented remote sensing systems. A common background and orientation for users of the LARS computer software system is provided
Disseminating technological information on remote sensing to potential users
The Laboratory for Applications of Remote Sensing developed materials and programs which range from short tutorial brochures to post-doctoral research programs which may span several years. To organize both the content and the instructional techniques, a matrix of instructional materials was conceptualized. Each row in the matrix represents a subject area in remote sensing and each column in the matrix represents a different type media or instructional strategy
Influence of moving breathers on vacancies migration
A vacancy defect is described by a Frenkel--Kontorova model with a
discommensuration. This vacancy can migrate when interacts with a moving
breather. We establish that the width of the interaction potential must be
larger than a threshold value in order that the vacancy can move forward. This
value is related to the existence of a breather centred at the particles
adjacent to the vacancy.Comment: 11 pages, 10 figure
Breathers and kinks in a simulated crystal experiment
We develop a simple 1D model for the scattering of an incoming particle
hitting the surface of mica crystal, the transmission of energy through the
crystal by a localized mode, and the ejection of atom(s) at the incident or
distant face. This is the first attempt to model the experiment described in
Russell and Eilbeck in 2007 (EPL, v. 78, 10004). Although very basic, the model
shows many interesting features, for example a complicated energy dependent
transition between breather modes and a kink mode, and multiple ejections at
both incoming and distant surfaces. In addition, the effect of a heavier
surface layer is modelled, which can lead to internal reflections of breathers
or kinks at the crystal surface.Comment: 15 pages, 12 figures, based on a talk given at the conference
"Localized Excitations in Nonlinear Complex Systems (LENCOS)", Sevilla
(Spain) July 14-17, 200
Selective Cytotoxicity of Rhodium Metalloinsertors in Mismatch Repair-Deficient Cells
Mismatches in DNA occur naturally during replication and as a result of endogenous DNA damaging agents, but the mismatch repair (MMR) pathway acts to correct mismatches before subsequent rounds of replication. Rhodium metalloinsertors bind to DNA mismatches with high affinity and specificity and represent a promising strategy to target mismatches in cells. Here we examine the biological fate of rhodium metalloinsertors bearing dipyridylamine ancillary ligands in cells deficient in MMR versus those that are MMR-proficient. These complexes are shown to exhibit accelerated cellular uptake which permits the observation of various cellular responses, including disruption of the cell cycle, monitored by flow cytometry assays, and induction of necrosis, monitored by dye exclusion and caspase inhibition assays, that occur preferentially in the MMR-deficient cell line. These cellular responses provide insight into the mechanisms underlying the selective activity of this novel class of targeted anticancer agents
Isotope separation using metallic vapor lasers
The isotope U235 is separated from a gasified isotope mixture of U235 and U238 by selectively exciting the former from the ground state utilizing resonant absorption of radiation from precisely tuned lasers. The excited isotope is then selectively ionized by electron bombardment. It then is separated from the remaining isotope mixture by electromagnetic separation
Double-discharge copper-vapor laser
Power supply for discharge pulses consists of two capacitors that are made to discharge synchronously with adjustable time intervals. First pulse is switched with hydrogen thyratron, and second by spark gap. Lasing action peaks for appropriate combination of these two parameters
Nonlinear optics in Xe-filled hollow-core PCF in high pressure and supercritical regimes
Supercritical Xe at 293 K offers a Kerr nonlinearity that can exceed that of
fused silica while being free of Raman scattering. It also has a much higher
optical damage threshold and a transparency window that extends from the UV to
the infrared. We report the observation of nonlinear phenomena, such as
self-phase modulation, in hollow-core photonic crystal fiber filled with
supercritical Xe. In the subcritical regime, intermodal four-wave-mixing
resulted in the generation of UV light in the HE12 mode. The normal dispersion
of the fiber at high pressures means that spectral broadening can clearly
obtained without influence from soliton effects or material damage
p-Wave stabilization of three-dimensional Bose-Fermi solitons
We explore bright soliton solutions of ultracold Bose-Fermi gases, showing
that the presence of p-wave interactions can remove the usual collapse
instability and support stable soliton solutions that are global energy minima.
A variational model that incorporates the relevant s- and p-wave interactions
in the system is established analytically and solved numerically to probe the
dependencies of the solitons on key experimental parameters. Under attractive
s-wave interactions, bright solitons exist only as meta-stable states
susceptible to collapse. Remarkably, the presence of repulsive p-wave
interactions alleviates this collapse instability. This dramatically widens the
range of experimentally-achievable soliton solutions and indicates greatly
enhanced robustness. While we focus specifically on the boson-fermion pairing
of 87Rb and 40K, the stabilization inferred by repulsive p-wave interactions
should apply to the wider remit of ultracold Bose-Fermi mixtures.Comment: 9 pages, 6 figure
Near-ionization-threshold emission in atomic gases driven by intense sub-cycle pulses
We study theoretically the dipole radiation of a hydrogen atom driven by an
intense sub-cycle pulse. The time-dependent Schr\"odinger equation for the
system is solved by ab initio calculation to obtain the dipole response.
Remarkably, a narrowband emission lasting longer than the driving pulse appears
at a frequency just above the ionization threshold. An additional calculation
using the strong field approximation also recovers this emission, which
suggests that it corresponds to the oscillation of nearly-bound electrons that
behave similarly to Rydberg electrons. The predicted phenomenon is unique to
ultrashort driving pulses but not specific to any particular atomic structure.Comment: 8 pages, 2 figure
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