System analysis for the Huntsville Operational Support Center distributed computer system

The Huntsville Operations Support Center (HOSC) is a distributed computer system used to provide real time data acquisition, analysis and display during NASA space missions and to perform simulation and study activities during non-mission times. The primary purpose is to provide a HOSC system simulation model that is used to investigate the effects of various HOSC system configurations. Such a model would be valuable in planning the future growth of HOSC and in ascertaining the effects of data rate variations, update table broadcasting and smart display terminal data requirements on the HOSC HYPERchannel network system. A simulation model was developed in PASCAL and results of the simulation model for various system configuraions were obtained. A tutorial of the model is presented and the results of simulation runs are presented. Some very high data rate situations were simulated to observe the effects of the HYPERchannel switch over from contention to priority mode under high channel loading

Property Tax Revenue Decline in the State of California and the Implications: An Examination of Selected Local Governments in the State of California

The Center for Responsible Lending projects California local governments to experience a $107 billion dollar decrease in home values and taxable property rolls as a result of subprime mortgage related foreclosures [Lending, 2008]. Due to Proposition 13, property taxes do not account for a substantial portion of local government revenue. They do, however, constitute 53$4 billion in education spending to offset a major $16 billion budget shortfall [Lin, Emergency cuts likely today, 2008]. The goal of this research, though limited in scope and nature, was to examine the property tax revenue decline as it relates to property tax delinquency (defined as percentage of property tax levied but uncollected within a given year) in the state of California. For this research, I proposed to measure the property tax delinquency rate as property tax delinquencies serve as local government economic “fiscal health” indicators and display the “lack of ability and obstacles of short-term financial management for governments” [Denison, Yan, & Zhao, 2007]. Therefore, the property tax delinquency rates of 11 California counties were examined to see if there was a statistically significant relationship between the dependent variable—county property tax delinquency rate—and a host of independent variables under the classifications of Race, Age, and Socioeconomic Indicators. It is important to understand this relationship to gain further insight into the complexities associated with the effects of the subprime market and resulting soft-housing market on California’s local government to see if certain criteria make counties more susceptible to experiencing property tax revenue decline. This is all done with hope that if local governments are aware of these factors, then they can prepare and plan accordingly as to mitigate these effects. The goal of this research, though limited in scope and nature, was to examine the property tax revenue decline as it relates to property tax delinquency (defined as percentage of property tax levied but uncollected within a given year) in the state of California. For this research, I proposed to measure the property tax delinquency rate as property tax delinquencies serve as local government economic “fiscal health” indicators and display the “lack of ability and obstacles of short-term financial management for governments” [Denison, Yan, & Zhao, 2007]. Therefore, the property tax delinquency rates of 11 California counties were examined to see if there was a statistically significant relationship between the dependent variable—county property tax delinquency rate—and a host of independent variables under the classifications of Race, Age, and Socioeconomic Indicators. It is important to understand this relationship to gain further insight into the complexities associated with the effects of the subprime market and resulting soft-housing market on California’s local government to see if certain criteria make counties more susceptible to experiencing property tax revenue decline. This is all done with hope that if local governments are aware of these factors, then they can prepare and plan accordingly as to mitigate these effects

The Carboxyl-Terminal Segment of Apolipoprotein A-V Undergoes a Lipid-Induced Conformational Change

Apolipoprotein (apo) A-V is a 343-residue, multidomain protein that plays an important role in regulation of plasma triglyceride homeostasis. Primary sequence analysis revealed a unique tetraproline sequence (Pro293-Pro296) near the carboxyl terminus of the protein. A peptide corresponding to the 48-residue segment beyond the tetraproline motif was generated from a recombinant apoA-V precursor wherein Pro295 was replaced by Met. Cyanogen bromide cleavage of the precursor protein, followed by negative affinity chromatography, yielded a purified peptide. Nondenaturing polyacrylamide gel electrophoresis verified that apoA-V(296-343) solubilizes phospholipid vesicles, forming a relatively heterogeneous population of reconstituted high-density lipoprotein with Stokes’ diameters\u3e17 nm. At the same time, apoA-V(296-343) failed to bind a spherical lipoprotein substrate in vitro. Far-UV circular dichroism spectroscopy revealed the peptide is unstructured in buffer yet adopts significant R-helical secondary structure in the presence of the lipid mimetic solvent trifluoroethanol (TFE; 50% v/v). Heteronuclear multidemensional NMR spectroscopy experiments were conducted with uniformly 15N- and 15N/13C-labeled peptide in 50% TFE. Peptide backbone assignment and secondary structure prediction using TALOSþ reveal the peptide adopts R-helix secondary structure from residues 309 to 334. In TFE, apoA-V(296-343) adopts an extended amphipathic R-helix, consistent with a role in lipoprotein binding as a component of full-length apoA-V

The geometry of fractal percolation

A well studied family of random fractals called fractal percolation is discussed. We focus on the projections of fractal percolation on the plane. Our goal is to present stronger versions of the classical Marstrand theorem, valid for almost every realization of fractal percolation. The extensions go in three directions: {itemize} the statements work for all directions, not almost all, the statements are true for more general projections, for example radial projections onto a circle, in the case $\dim_H >1$, each projection has not only positive Lebesgue measure but also has nonempty interior. {itemize}Comment: Survey submitted for AFRT2012 conferenc

Higher-dimensional multifractal value sets for conformal infinite graph directed Markov systems

We give a description of the level sets in the higher dimensional multifractal formalism for infinite conformal graph directed Markov systems. If these systems possess a certain degree of regularity this description is complete in the sense that we identify all values with non-empty level sets and determine their Hausdorff dimension. This result is also partially new for the finite alphabet case.Comment: 20 pages, 1 figur

Highlights of OH, H2SO4, and methane sulfonic acid measurements made aboard the NASA P-3B during Transport and Chemical Evolution over the Pacific

Measurements of hydroxyl radical (OH), sulfuric acid (H2SO4), and methane sulfonic acid (MSA) were performed aboard the NASA P-3B using the selected ion chemical ionization mass spectrometry technique during the Transport and Chemical Evolution over the Pacific (TRACE-P) study. Photochemical box model calculations of OH concentrations yielded generally good agreement with an overall tendency to overestimate the measured OH by ∼20%. Further analysis reveals that this overestimation is present only at altitudes greater than ∼1.5 km, with the model underestimating OH measurements at lower altitudes. Boundary layer H2SO4 measurements, performed in a volcanic plume off the southern coast of Japan, revealed some of the largest marine boundary layer H2SO4 concentrations ever observed and were accompanied by new particle formation. Nighttime measurements of OH, H2SO4, and MSA in the remote pacific off Midway Island revealed significant boundary layer concentrations of H2SO4 and MSA, indicating evidence of nighttime boundary layer oxidation processes but in the absence of OH. A cursory exploration of the sources of production of the H2SO4 and MSA observed at night is presented

On conformal measures and harmonic functions for group extensions

We prove a Perron-Frobenius-Ruelle theorem for group extensions of topological Markov chains based on a construction of $\sigma$-finite conformal measures and give applications to the construction of harmonic functions.Comment: To appear in Proceedings of "New Trends in Onedimensional Dynamics, celebrating the 70th birthday of Welington de Melo

The Cayo del Oso Site (41NU2) Volume II Results of Archeological Monitoring of Spur 3, Corpus Christi, Nueces County, Texas 2000-2007

This report is the second volume in a two volume set (see Jackson et al. 2004) detailing the archeological work conducted at site 41NU2 over several years. This volume focuses on the results of construction monitoring associated with road improvements to Spur 3, in Corpus Christi. The work was conducted under Texas Antiquities Committee Permit Number 2445, originally issued to Dr. Robert Hard, who served as the Principal Investigator during the early phases of the project. In 2001, the permit was transferred to Dr. Raymond P. Mauldin, who served as the Principal Investigator the remainder of the project.