8,936 research outputs found
The Role of Proximity in Reducing Auto Travel: Using VMT to Identify Key Locations for Development, from Downtown to the Exurbs
The purpose of this dissertation is to discover the VMT impact of each level of proximity in order to help government identify key locations for housing development, and thereby lower VMT and reduce dependence on foreign oil. By discovering the VMT impact of each level of proximity, this dissertation provides a) the first known means of calculating the proximity-based VMT benefit of subject locations by individual proximity level, and b) the new finding that it is likely that high VMT benefit can be achieved at moderate proximity levels acceptable to many households, enabling representative governments to be politically successful while promoting housing in locations that will lower the average VMT of the population.
After discussing the impetus for the work, this dissertation presents a theory of the determinants of VMT, searches the literature for appropriate techniques for empirical analysis of the proximity-VMT relationship, and presents results of the empirical research to be expected based on the presented theory and literature.
Empirical efforts are used to discover VMT impact by proximity level using three differing measures of proximity: density, distance-threshold-based total opportunities, and centrality. In the first effort, national data is used to discover VMT impact by proximity level, for both population and employment density. In order to determine the role played by alternative modes in the VMT-density curves of the first effort, the second effort uses national data to discover the impact of each level of density on usage of alternative modes. In the third and final effort, data from Hampton Roads, Virginia, are used to discover the VMT impact of each level of opportunity and centrality.
Governments can apply the discovered VMT impact of each level of proximity--via a described VMT Benefit Technique --to accurately determine the VMT benefit of a given location, and use the VMT benefits of a set of candidate areas to select key locations for development.
In addition, the discovered VMT impact of each level of proximity informs the key hypothesis of this dissertation that there exists a sweet spot on the VMT-proximity curve that has high VMT benefit and a proximity level acceptable to many households. Although the hypothesis tests indicate that it is not certain that the sweet spot exists, the mean coefficients of the models indicate that it is likelythat the sweet spot exists, i.e. that there are high-VMT-benefit proximity levels acceptable to many households. The overall implication of this is that representative governments in the U.S. who promote housing development at these moderate levels of proximity will not only lower average VMT in the short term, but they will not be punished politically for doing so, and therefore may be successful in thereby lowering average VMT in the long term.
In summary, the dissertation provides encouragement to governments hoping to lower average VMT and an accurate method of calculating VMT for choosing SGAs with which to actually lower average VMT. It is hoped that this combination will help U.S. governments become independent of foreign oil
History and Function of the Pep Club at Ogden High School
The purpose of this study is to determine the functions of the Ogden High School Pep Club in the light of the present needs of the Ogden High School student body, and to attempt to show by means of an historical resume, the progressive development of this organization. The Pep Club was founded at Ogden High School by persons who felt that there was a definite need for such an organization. The club was organized to meet the needs of the student body, and as the years passed, these changing needs were reflected in the club, for the club adjusted accordingly. Today the activities are more diversified than those of a few years ago; therefore the program should be adjusted and developed so as to be of greater value to the students in secondary schools
Kinetic Characterization of the Shigella Type Three Secretion System ATPase Spa47 Using α-32P ATP
ATPases represent a diverse class of enzymes that utilize ATP hydrolysis to support critical biological functions such as driving ion pumps, providing mechanical work, unfolding/folding proteins, and supporting otherwise thermodynamically unfavorable chemical reactions. We have recently shown that the Shigella protein Spa47 is an ATPase that supports protein secretion through its specialized type three secretion apparatus (T3SA), supporting infection of human host cells. Characterizing ATPases, such as Spa47, requires a means to accurately determine enzyme activity (ATP hydrolysis) as a function of time, reaction conditions, and potential cofactors, regulators, inhibitors, etc. Here, we describe a detailed protocol for characterizing the enzyme kinetics of Spa47 using a direct α−32P ATPase assay
The orthogonal fitting procedure for determination of the empirical {\Sigma} - D relations for supernova remnants: application to starburst galaxy M82
The radio surface brightness-to-diameter ({\Sigma} - D) relation for
supernova remnants (SNRs) in the starburst galaxy M82 is analyzed in a
statistically more robust manner than in the previous studies that mainly
discussed sample quality and related selection effects. The statistics of data
fits in log {\Sigma} - log D plane are analyzed by using vertical (standard)
and orthogonal regressions. As the parameter values of D - {\Sigma} and
{\Sigma} - D fits are invariant within the estimated uncertainties for
orthogonal regressions, slopes of the empirical {\Sigma} - D relations should
be determined by using the orthogonal regression fitting procedure. Thus
obtained {\Sigma} - D relations for samples which are not under severe
influence of the selection effects could be used for estimating SNR distances.
Using the orthogonal regression fitting procedure {\Sigma} - D slope {\beta}
\approx 3.9 is obtained for the sample of 31 SNRs in M82. The results of
implemented Monte Carlo simulations show that the sensitivity selection effect
does not significantly influence the slope of M82 relation. This relation could
be used for estimation of distances to SNRs that evolve in denser interstellar
environment, with number denisty up to 1000 particles per cm3 .Comment: 14 pages, 3 figures, no changes, previous version had a typo in
publication related comment, accepted for publication in Ap
Picosecond electrical spectroscopy using monolithic GaAs circuits
This article describes an experimental apparatus for free-space mm-wave transmission measurements (spectroscopy). GaAs nonlinear transmission lines and sampling circuits are used as picosecond pulse generators and detectors, with planar monolithic bowtie antennas with associated substrate lenses used as the radiating and receiving elements. The received pulse is 270 mV amplitude and 2.4 ps rise time. Through Fourier transformation of the received pulse, 30–250 GHz measurements are demonstrated with <=0.3 dB (rms) accuracy
Image Reconstruction with a LaBr3-based Rotational Modulator
A rotational modulator (RM) gamma-ray imager is capable of obtaining
significantly better angular resolution than the fundamental geometric
resolution defined by the ratio of detector diameter to mask-detector
separation. An RM imager consisting of a single grid of absorbing slats
rotating ahead of an array of a small number of position-insensitive detectors
has the advantage of fewer detector elements (i.e., detector plane pixels) than
required by a coded aperture imaging system with comparable angular resolution.
The RM therefore offers the possibility of a major reduction in instrument
complexity, cost, and power. A novel image reconstruction technique makes it
possible to deconvolve the raw images, remove sidelobes, reduce the effects of
noise, and provide resolving power a factor of 6 - 8 times better than the
geometric resolution. A 19-channel prototype RM developed in our laboratory at
Louisiana State University features 13.8 deg full-angle field of view, 1.9 deg
geometric angular resolution, and the capability of resolving sources to within
35' separation. We describe the technique, demonstrate the measured performance
of the prototype instrument, and describe the prospects for applying the
technique to either a high-sensitivity standoff gamma-ray imaging detector or a
satellite- or balloon-borne gamma-ray astronomy telescope.Comment: submitted to Nuclear Instrument & Methods, special edition: SORMA
2010 on June 16, 201
Adhesive F-actin Waves: A Novel Integrin-Mediated Adhesion Complex Coupled to Ventral Actin Polymerization
At the leading lamellipodium of migrating cells, protrusion of an Arp2/3-nucleated actin network is coupled to formation of integrin-based adhesions, suggesting that Arp2/3-mediated actin polymerization and integrin-dependent adhesion may be mechanistically linked. Arp2/3 also mediates actin polymerization in structures distinct from the lamellipodium, in “ventral F-actin waves” that propagate as spots and wavefronts along the ventral plasma membrane. Here we show that integrins engage the extracellular matrix downstream of ventral F-actin waves in several mammalian cell lines as well as in primary mouse embryonic fibroblasts. These “adhesive F-actin waves” require a cycle of integrin engagement and disengagement to the extracellular matrix for their formation and propagation, and exhibit morphometry and a hierarchical assembly and disassembly mechanism distinct from other integrin-containing structures. After Arp2/3-mediated actin polymerization, zyxin and VASP are co-recruited to adhesive F-actin waves, followed by paxillin and vinculin, and finally talin and integrin. Adhesive F-actin waves thus represent a previously uncharacterized integrin-based adhesion complex associated with Arp2/3-mediated actin polymerization
- …