Comparing Management Approaches for Automatic Test Systems: A Strategic Missile Case Study

From 1980 to 1992, the DoD spent over $50 billion acquiring Automatic Test Systems (ATS) used to test weapon systems. At that time, procuring unique ATS to support single weapon systems was the norm. In 1994, the DoD made a dramatic change to their ATS acquisition policy; common ATS that supported multiple weapon systems was preferred over ATS tailored to support a single weapon system. Expected benefits of this new policy included: more reliable equipment, increased supportability, decreased cost, smaller logistics footprint, and decreased manning. To date, the common ATS initiative has garnered little support AF-wide due to lack of substantive data supporting the expected benefits in a practical setting. The majority of the ATS procured in the 1980-1992 bubble is still in service but is facing severe aging and obsolescence issues. The purpose of this research was to compare two ATS programs selected because of their numerous similarities, with their singular difference being whether the equipment was managed as common core (Cruise Missile ATS) or managed as part of the weapon system (ICBM ATS). This research seeks to satisfy two goals. The first goal of this case study was to determine if the expected benefits of common ATS are being realized in a practical setting. Second, if the expected benefits are not being met, the hindrances should be understood so they may be corrected

MARGINAL AGRICULTURAL LAND CLASSIFICATION: A NEW APPROACH

Land Economics/Use,

High rates of HIV testing despite low perceived HIV risk among African-American sexually transmitted disease patients.

In the current diagnosis-based, human immunodeficiency virus (HIV) prevention climate, previous testing among persons at elevated HIV risk has cost and efficacy implications, as it signals continued behavioral risk, limited HIV knowledge or overuse of services. This study sought to determine the proportion of African Americans newly seeking sexually transmitted disease (STD) diagnosis who previously had obtained HIV counseling and testing. This was a clinic-based, cross-sectional survey of African-American adults (N=408) seeking STO diagnosis at a public STD clinic located in a high-HIV and STD prevalence city in the U.S. south. Eighty-four percent of respondents had previously obtained HIV counseling and testing: 68% had previously obtained care at the clinic. Sixty-five percent of respondents perceived themselves as having low or no HIV risk. Seventy-two percent correctly answered > or = 3 of 4 HIV knowledge items. Although diagnosis-based HIV prevention initiatives promote HIV counseling and testing for both primary and secondary HIV prevention, these findings suggest that many African-American STD patients remain at risk following testing. Future research should explore how the counseling portion of standard HIV counseling and testing influences subsequent knowledge, attitudes, risk perceptions and behaviors

Snapshots of a protein folding intermediate

We have investigated the folding dynamics of Thermus thermophilus cytochrome c_(552) by time-resolved fluorescence energy transfer between the heme and each of seven site-specific fluorescent probes. We have found both an equilibrium unfolding intermediate and a distinct refolding intermediate from kinetics studies. Depending on the protein region monitored, we observed either two-state or three-state denaturation transitions. The unfolding intermediate associated with three-state folding exhibited native contacts in β-sheet and C-terminal helix regions. We probed the formation of a refolding intermediate by time-resolved fluorescence energy transfer between residue 110 and the heme using a continuous flow mixer. The intermediate ensemble, a heterogeneous mixture of compact and extended polypeptides, forms in a millisecond, substantially slower than the ∼100-μs formation of a burst-phase intermediate in cytochrome c. The surprising finding is that, unlike for cytochrome c, there is an observable folding intermediate, but no microsecond burst phase in the folding kinetics of the structurally related thermostable protein

Transit Timing Observations from Kepler: VI. Potentially interesting candidate systems from Fourier-based statistical tests

We analyze the deviations of transit times from a linear ephemeris for the Kepler Objects of Interest (KOI) through Quarter six (Q6) of science data. We conduct two statistical tests for all KOIs and a related statistical test for all pairs of KOIs in multi-transiting systems. These tests identify several systems which show potentially interesting transit timing variations (TTVs). Strong TTV systems have been valuable for the confirmation of planets and their mass measurements. Many of the systems identified in this study should prove fruitful for detailed TTV studies.Comment: 32 pages, 6 of text and one long table, Accepted to Ap

Transit Timing Observations from Kepler: VII. Confirmation of 27 planets in 13 multiplanet systems via Transit Timing Variations and orbital stability

We confirm 27 planets in 13 planetary systems by showing the existence of statistically significant anti-correlated transit timing variations (TTVs), which demonstrates that the planet candidates are in the same system, and long-term dynamical stability, which places limits on the masses of the candidates---showing that they are planetary. %This overall method of planet confirmation was first applied to \kepler systems 23 through 32. All of these newly confirmed planetary systems have orbital periods that place them near first-order mean motion resonances (MMRs), including 6 systems near the 2:1 MMR, 5 near 3:2, and one each near 4:3, 5:4, and 6:5. In addition, several unconfirmed planet candidates exist in some systems (that cannot be confirmed with this method at this time). A few of these candidates would also be near first order MMRs with either the confirmed planets or with other candidates. One system of particular interest, Kepler-56 (KOI-1241), is a pair of planets orbiting a 12th magnitude, giant star with radius over three times that of the Sun and effective temperature of 4900 K---among the largest stars known to host a transiting exoplanetary system.Comment: 12 pages, 13 figures, 5 tables. Submitted to MNRA

Towards a molecular mechanism underlying mitochondrial protein import through the TOM and TIM23 complexes

Nearly all mitochondrial proteins need to be targeted for import from the cytosol. For the majority, the first port of call is the translocase of the outer membrane (TOM complex), followed by a procession of alternative molecular machines, conducting transport to their final destination. The pre-sequence translocase of the inner membrane (TIM23-complex) imports proteins with cleavable pre-sequences. Progress in understanding these transport mechanisms has been hampered by the poor sensitivity and time resolution of import assays. However, with the development of an assay based on split NanoLuc luciferase, we can now explore this process in greater detail. Here, we apply this new methodology to understand how ∆ψ and ATP hydrolysis, the two main driving forces for import into the matrix, contribute to the transport of pre-sequence-containing precursors (PCPs) with varying properties. Notably, we found that two major rate-limiting steps define PCP import time: passage of PCP across the outer membrane and initiation of inner membrane transport by the pre-sequence – the rates of which are influenced by PCP size and net charge. The apparent distinction between transport through the two membranes (passage through TOM is substantially complete before PCP-TIM engagement) is in contrast with the current view that import occurs through TOM and TIM in a single continuous step. Our results also indicate that PCPs spend very little time in the TIM23 channel – presumably rapid success or failure of import is critical for maintenance of mitochondrial fitness

A Search for Exozodiacal Clouds with Kepler

Planets embedded within dust disks may drive the formation of large scale clumpy dust structures by trapping dust into resonant orbits. Detection and subsequent modeling of the dust structures would help constrain the mass and orbit of the planet and the disk architecture, give clues to the history of the planetary system, and provide a statistical estimate of disk asymmetry for future exoEarth-imaging missions. Here we present the first search for these resonant structures in the inner regions of planetary systems by analyzing the light curves of hot Jupiter planetary candidates identified by the Kepler mission. We detect only one candidate disk structure associated with KOI 838.01 at the 3-sigma confidence level, but subsequent radial velocity measurements reveal that KOI 838.01 is a grazing eclipsing binary and the candidate disk structure is a false positive. Using our null result, we place an upper limit on the frequency of dense exozodi structures created by hot Jupiters. We find that at the 90% confidence level, less than 21% of Kepler hot Jupiters create resonant dust clumps that lead and trail the planet by ~90 degrees with optical depths >~5*10^-6, which corresponds to the resonant structure expected for a lone hot Jupiter perturbing a dynamically cold dust disk 50 times as dense as the zodiacal cloud.Comment: 22 pages, 6 figures, Accepted for publication in Ap