1,722 research outputs found
The Funny Place : Australian Literature and the War in Vietnam
An analysis of Australian novels about the Vietnam War
Dynamics and calcium association to the N-terminal regulatory domain of human cardiac troponin C: a multiscale computational study.
Troponin C (TnC) is an important regulatory molecule in cardiomyocytes. Calcium binding to site II in TnC initiates a series of molecular events that result in muscle contraction. The most direct change upon Ca(2+) binding is an opening motion of the molecule that exposes a hydrophobic patch on the surface allowing for Troponin I to bind. Molecular dynamics simulations were used to elucidate the dynamics of this crucial protein in three different states: apo, Ca(2+)-bound, and Ca(2+)-TnI-bound. Dynamics between the states are compared, and the Ca(2+)-bound system is investigated for opening motions. On the basis of the simulations, NMR chemical shifts and order parameters are calculated and compared with experimental observables. Agreement indicates that the simulations sample the relevant dynamics of the system. Brownian dynamics simulations are used to investigate the calcium association of TnC. We find that calcium binding gives rise to correlative motions involving the EF hand and collective motions conducive of formation of the TnI-binding interface. We furthermore indicate the essential role of electrostatic steering in facilitating diffusion-limited binding of Ca(2+)
Probing Light Atoms at Sub-nanometer Resolution: Realization of Scanning Transmission Electron Microscope Holography
Atomic resolution imaging in transmission electron microscopy (TEM) and
scanning TEM (STEM) of light elements in electron-transparent materials has
long been a challenge. Biomolecular materials, for example, are rapidly altered
when illuminated with electrons. These issues have driven the development of
TEM and STEM techniques that enable the structural analysis of electron
beam-sensitive and weakly scattering nano-materials. Here, we demonstrate such
a technique, STEM holography, capable of absolute phase and amplitude object
wave measurement with respect to a vacuum reference wave. We use an
amplitude-dividing nanofabricated grating to prepare multiple spatially
separated electron diffraction probe beams focused at the sample plane, such
that one beam transmits through the specimen while the others pass through
vacuum. We raster-scan the diffracted probes over the region of interest. We
configure the post specimen imaging system of the microscope to diffraction
mode, overlapping the probes to form an interference pattern at the detector.
Using a fast-readout, direct electron detector, we record and analyze the
interference fringes at each position in a 2D raster scan to reconstruct the
complex transfer function of the specimen, t(x). We apply this technique to
image a standard target specimen consisting of gold nanoparticles on a thin
amorphous carbon substrate, and demonstrate 2.4 angstrom resolution phase
images. We find that STEM holography offers higher phase-contrast of the
amorphous material while maintaining Au atomic lattice resolution when compared
with high angle annular dark field STEM.Comment: 9 pages, 5 figures in main text, 1 supplemental figure in the
appendi
A Concordance Between Ten-Digit U.S. Harmonized System Codes and SIC/NAICS Product Classes and Industries
This paper provides and describes concordances between the ten-digit Harmonized System (HS) categories used to classify products in U.S. international trade and the four-digit SIC and six-digit NAICS industries that cover the years 1989 to 2006. We also provide concordances between ten-digit HS codes and the five-digit SIC and seven-digit NAICS product classes used to classify U.S. manufacturing production. Finally, we briefly describe how these concordances might be applied in current empirical international trade research.
Concording U.S. Harmonized System Categories Over Time
This paper: outlines an algorithm for concording U.S. ten-digit Harmonized System export and import codes over time; describes the concordances we construct for 1989 to 2004; and provides Stata code that can be used to construct similar concordances for arbitrary beginning and ending years from 1989 to 2007.
Australian Chivalry: Australian Chivalry?
A discussion of the collection of war stories entitled Australian Chivalry
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