5,900 research outputs found
Processing and Transmission of Information
Contains research objectives and reports on two research projects
Processing and Transmission of Information
Contains research objectives and reports on one research project.Lincoln Laboratory (Purchase Order DDL-B187)Department of the ArmyDepartment of the NavyDepartment of the Air Force under Contract AF19(122)-45
Bioelectronic DNA detection of human papillomaviruses using eSensor™: a model system for detection of multiple pathogens
BACKGROUND: We used human papillomaviruses (HPV) as a model system to evaluate the utility of a nucleic acid, hybridization-based bioelectronic DNA detection platform (eSensor™) in identifying multiple pathogens. METHODS: Two chips were spotted with capture probes consisting of DNA oligonucleotide sequences specific for HPV types. Electrically conductive signal probes were synthesized to be complementary to a distinct region of the amplified HPV target DNA. A portion of the HPV L1 region that was amplified by using consensus primers served as target DNA. The amplified target was mixed with a cocktail of signal probes and added to a cartridge containing a DNA chip to allow for hybridization with complementary capture probes. RESULTS: Two bioelectric chips were designed and successfully detected 86% of the HPV types contained in clinical samples. CONCLUSIONS: This model system demonstrates the potential of the eSensor platform for rapid and integrated detection of multiple pathogens
Sensitive VLBI Continuum and H I Absorption Observations of NGC 7674: First Scientific Observations with the Combined Array VLBA, VLA & Arecibo
We present phase-referenced VLBI observations of the radio continuum emission
from, and the H I 21 cm absorption toward, the Luminous Infrared Galaxy NGC
7674. The observations were carried out at 1380 MHz using the VLBA, the phased
VLA, and theArecibo radio telescope. These observations constitute the first
scientific use of the Arecibo telescope in a VLBI observation with the VLBA.
The high- and low-resolution radio continuum images reveal several new
continuum structures in the nuclear region of this galaxy. At ~100 mas
resolution, we distinguish six continuum structures extending over 1.4 arcsec,
with a total flux density of 138 mJy. Only three of these structures were known
previously. All these structures seem to be related to AGN activity. At the
full resolution of the array, we only detect two of the six continuum
structures. Both are composed of several compact components with brightness
temperatures on the order of K. While it is possible that one of these
compact structures could host an AGN, they could also be shock-like features
formed by the interaction of the jet with compact interstellar clouds in the
nuclear region of this galaxy. Complex H I absorption is detected with our VLBI
array at both high and low angular resolution. Assuming that the widest H I
feature is associated with a rotating H I disk or torus feeding a central AGN,
we estimate an enclosed dynamical mass of ~7 x 10^7 M_sun, comparable to the
value derived from the hidden broad H emission in this galaxy. The
narrower H I lines could represent clumpy neutral hydrogen structures in the H
I torus. The detection of H I absorption toward some of the continuum
components, and its absence toward others, suggest an inclined H I disk or
torus in the central region of NGC 7674.Comment: 37 pages, 11 figures. ApJ accepted. To appear in the Nov. 10, 2003
issue of ApJ. Please use the PDF version if the postscript doesn't show the
figure
Resonant continuum in the Hartree-Fock+BCS approximation
A method for incorporating the effect of the resonant continuum into
Hartree-Fock+BCS equations is proposed. The method is applied for the case of
a neutron-rich nucleus calculated with a Skyrme-type force plus a zero-range
pairing interaction and the results are compared with
Hartree-Fock-Bogoliubov calculations. It is shown that the widths of resonant
states have an important effect on the pairing properties of nuclei close to
the drip line.Comment: 9 pages, 2 figures, comparison with HFB adde
The instability of Alexander-McTague crystals and its implication for nucleation
We show that the argument of Alexander and McTague, that the bcc crystalline
structure is favored in those crystallization processes where the first order
character is not too pronounced, is not correct. We find that any solution that
satisfies the Alexander-McTague condition is not stable. We investigate the
implication of this result for nucleation near the pseudo- spinodal in
near-meanfield systems.Comment: 20 pages, 0 figures, submitted to Physical Review
On the Nature of Intrinsic Absorption in Reddened Seyfert 1 Galaxies
We discuss the origin of the ``dusty lukewarm absorber'', which we previously
identified in the reddened Seyfert 1 galaxies NGC 3227 and Akn 564. This
absorber is characterized by saturated UV absorption lines (C IV, N V) near the
systemic velocity of the host galaxy, and is likely responsible for reddening
both the continuum and the emission lines (including those from the narrow-line
region) from these Seyferts. From a large sample of Seyfert 1 galaxies, we find
that continuum reddening (as measured by UV color) tends to increase with
inclination of the host galaxy. Furthermore, reddened, inclined Seyfert
galaxies observed at moderate to high spectral resolution all show evidence for
dusty lukewarm absorbers. We suggest that these absorbers lie in the plane of
the host galaxy at distances > 100 pc from the nucleus, and are physically
distinct from the majority of intrinsic absorbers that are outflowing from the
nucleus.Comment: 14 pages, including 2 figures, accepted for publication in the
Astrophysical Journal (Letters
Present and future use of antimicrobials in pigs in developing countries and case studies from Uganda and Vietnam
Demand for pork is growing rapidly in developing countries, and will be mostly met by intensive production. Although this can produce large quantities of affordable meat, it can have environmental, social and human health externalities. We report on recent studies conducted by ILRI and partners on antimicrobial use in pork production in developing countries and antimicrobial resistance (AMR) in pork
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