6,239 research outputs found
ELSA: An Integrated, Semi-Automated Nebular Abundance Package
We present ELSA, a new modular software package, written in C, to analyze and
manage spectroscopic data from emission-line objects. In addition to
calculating plasma diagnostics and abundances from nebular emission lines, the
software provides a number of convenient features including the ability to
ingest logs produced by IRAF's splot task, to semi-automatically merge spectra
in different wavelength ranges, and to automatically generate various data
tables in machine-readable or LaTeX format. ELSA features a highly
sophisticated interstellar reddening correction scheme that takes into account
temperature and density effects as well as He II contamination of the hydrogen
Balmer lines. Abundance calculations are performed using a 5-level atom
approximation with recent atomic data, based on R. Henry's ABUN program.
Improvements planned in the near future include use of a three-region
ionization model, similar to IRAF's nebular package, error propagation, and the
addition of ultraviolet and infrared line analysis capability. Detailed
documentation for all aspects of ELSA are available at
http://www.williams.edu/Astronomy/research/PN .Comment: 2 pages, contributed paper, IAU Symp. 234, Planetary Nebulae in Our
Galaxy and Beyon
Processing and Transmission of Information
Contains reports on three research projects.National Aeronautics and Space Administration (Grant NGL-22-009-013)Joint Services Electronics Programs (U.S. Army, U.S. Navy, and U.S. Air Force) under Contract DA 28-043-AMC-02536(E
Rhetoric in the language of real estate marketing
“Des. Res.”, “rarely available”, “viewing essential” – these are all part of the peculiar parlance of housing advertisements which contain a heady mix of euphemism, hyperbole and superlative. Of interest is whether the selling agent’s penchant for rhetoric is spatially uniform or whether there are variations across the urban system. We are also interested in how the use of superlatives varies over the market cycle and over the selling season. For example, are estate agents more inclined to use hyperbole when the market is buoyant or when it is flat, and does it matter whether a house is marketed in the summer or winter? This paper attempts to answer these questions by applying textual analysis to a unique dataset of 49,926 records of real estate transactions in the Strathclyde conurbation over the period 1999 to 2006. The analysis opens up a new avenue of research into the use of real estate rhetoric and its interaction with agency behaviour and market dynamics
Nanoscale Weibull Statistics
In this paper a modification of the classical Weibull Statistics is developed
for nanoscale applications. It is called Nanoscale Weibull Statistics. A
comparison between Nanoscale and classical Weibull Statistics applied to
experimental results on fracture strength of carbon nanotubes clearly shows the
effectiveness of the proposed modification. A Weibull's modulus around 3 is,
for the first time, deduced for nanotubes. The approach can treat (also) a
small number of structural defects, as required for nearly defect free
structures (e.g., nanotubes) as well as a quantized crack propagation (e.g., as
a consequence of the discrete nature of matter), allowing to remove the
paradoxes caused by the presence of stress-intensifications
Investigation, Development, and Evaluation of Performance Proving for Fault-tolerant Computers
A number of methodologies for verifying systems and computer based tools that assist users in verifying their systems were developed. These tools were applied to verify in part the SIFT ultrareliable aircraft computer. Topics covered included: STP theorem prover; design verification of SIFT; high level language code verification; assembly language level verification; numerical algorithm verification; verification of flight control programs; and verification of hardware logic
Electrostatics of ions inside the nanopores and trans-membrane channels
A model of a finite cylindrical ion channel through a phospholipid membrane
of width separating two electrolyte reservoirs is studied. Analytical
solution of the Poisson equation is obtained for an arbitrary distribution of
ions inside the trans-membrane pore. The solution is asymptotically exact in
the limit of large ionic strength of electrolyte on the two sides of membrane.
However, even for physiological concentrations of electrolyte, the
electrostatic barrier sizes found using the theory are in excellent agreement
with the numerical solution of the Poisson equation. The analytical solution is
used to calculate the electrostatic potential energy profiles for pores
containing charged protein residues. Availability of a semi-exact interionic
potential should greatly facilitate the study of ionic transport through
nanopores and ion channels
Implementation of NMR quantum computation with para-hydrogen derived high purity quantum states
We demonstrate the first implementation of a quantum algorithm on a liquid
state nuclear magnetic resonance (NMR) quantum computer using almost pure
states. This was achieved using a two qubit device where the initial state is
an almost pure singlet nuclear spin state of a pair of 1H nuclei arising from a
chemical reaction involving para-hydrogen. We have implemented Deutsch's
algorithm for distinguishing between constant and balanced functions with a
single query.Comment: 7 pages RevTex including 6 figures. Figures 4-6 are low quality to
save space. Submitted to Phys Rev
Integration of a satellite ground support system based on analysis of the satellite ground support domain
This analysis defines a complete set of ground support functions based on those practiced in real space flight operations during the on-orbit phase of a mission. These functions are mapped against ground support functions currently in use by NASA and DOD. Software components to provide these functions can be hosted on RISC-based work stations and integrated to provide a modular, integrated ground support system. Such modular systems can be configured to provide as much ground support functionality as desired. This approach to ground systems has been widely proposed and prototyped both by government institutions and commercial vendors. The combined set of ground support functions we describe can be used as a standard to evaluate candidate ground systems. This approach has also been used to develop a prototype of a modular, loosely-integrated ground support system, which is discussed briefly. A crucial benefit to a potential user is that all the components are flight-qualified, thus giving high confidence in their accuracy and reliability
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