360 research outputs found
An Examination of the Demographic and Career Progression of Air Force Institute of Technology Cost Analysis Graduates
The Air Force Institute of Technology (AFIT) was asked to develop a graduate curriculum to support cost analysts in the acquisition arena in October 1980. The first class entered in May 1982 and graduated in September 1983 with Master of Science degrees in Systems Management. This degree program gained autonomy by offering its first true Master of Science degree in Cost Analysis in 1988. Now there are nearly thirteen years of graduate cost analysts (GCAs) in the workforce. This thesis examined the impact this program has had on these graduates and the Air Force. Surveys were mailed out to 73 of the 75 currently active-duty graduates in the classes from 1983 through 1994. Forty responses were received and evaluated. The general consensus is that the GCA program is very useful to the graduates and beneficial to their careers. The main strengths of the program include the ACEIT software training and the combination of Department of Defense (DOD) application, regression, and statistics. The weaknesses of the program include a lack of training to actually complete a cost estimate and a need for more in-depth education regarding budget topics. Overall, graduates believe this program could not be replaced by a civilian institution
The percutaneous absorption of soman in a damaged skin porcine model and the evaluation of WoundStat⢠as a topical decontaminant
PURPOSE: The aim of this study was to evaluate a candidate haemostat (WoundStatâ˘), down-selected from previous in vitro studies, for efficacy as a potential skin decontaminant against the chemical warfare agent pinacoyl methylfluorophosphonate (Soman, GD) using an in vivo pig model. MATERIALS AND METHODS: An area of approximately 3âcm2 was dermatomed from the dorsal ear skin to a nominal depth of 100âÂľm. A discrete droplet of 14C-GD (300âÂľg kg-1) was applied directly onto the surface of the damaged skin at the centre of the dosing site. Animals assigned to the treatment group were given a 2âg application of WoundStat⢠30âs after GD challenge. The decontamination efficacy of WoundStat⢠against GD was measured by the direct quantification of the distribution of 14C-GD, as well as routine determination of whole blood cholinesterase and physiological measurements. RESULTS: WoundStat⢠sequestered approximately 70% of the applied 14C-GD. Internal radiolabel recovery from treated animals was approximately 1% of the initially applied dose. Whole blood cholinesterase levels decreased to less than 10% of the original value by 15âmin post WoundStat⢠treatment and gradually decreased until the onset of apnoea or until euthanasia. All treated animals showed signs of GD intoxication that could be grouped into early (mastication, fasciculations and tremor), intermediate (miosis, salivation and nasal secretions) and late onset (lacrimation, body spasm and apnoea) effects. Two of the six WoundStat⢠treated animals survived the study duration. CONCLUSIONS: The current study has shown that the use of WoundStat⢠as a decontaminant on damaged pig ear skin was unable to fully protect against GD toxicity. Importantly, the findings indicate that the use of WoundStat⢠in GD contaminated wounds would not exacerbate GD toxicity. These data suggest that absorbent haemostatic products may offer some limited functionality as wound decontaminants.Peer reviewedFinal Accepted Versio
The Aquarius Superclusters - I. Identification of Clusters and Superclusters
We study the distribution of galaxies and galaxy clusters in a 10^deg x 6^deg
field in the Aquarius region. In addition to 63 clusters in the literature, we
have found 39 new candidate clusters using a matched-filter technique and a
counts-in-cells analysis. From redshift measurements of galaxies in the
direction of these cluster candidates, we present new mean redshifts for 31
previously unobserved clusters, while improved mean redshifts are presented for
35 other systems. About 45% of the projected density enhancements are due to
the superposition of clusters and/or groups of galaxies along the line of
sight, but we could confirm for 72% of the cases that the candidates are real
physical associations similar to the ones classified as rich galaxy clusters.
On the other hand, the contamination due to galaxies not belonging to any
concentration or located only in small groups along the line of sight is ~ 10%.
Using a percolation radius of 10 h^{-1} Mpc (spatial density contrast of about
10), we detect two superclusters of galaxies in Aquarius, at z = 0.086 and at z
= 0.112, respectively with 5 and 14 clusters. The latter supercluster may
represent a space overdensity of about 160 times the average cluster density as
measured from the Abell et al. (1989) cluster catalog, and is possibly
connected to a 40 h^{-1} Mpc filament from z ~ 0.11 to 0.14.Comment: LateX text (21 pages) and 12 (ps/eps/gif) figures; figures 5a, 5b and
6 are not included in the main LateX text; to be published in the
Astronomical Journal, March issu
Variational quantum chemistry requires gate-error probabilities below the fault-tolerance threshold
The variational quantum eigensolver (VQE) is a leading contender for useful
quantum advantage in the NISQ era. The interplay between quantum processors and
classical optimisers is believed to make the VQE noise resilient. Here, we
probe this hypothesis. We use full density-matrix simulations to rank the noise
resilience of leading gate-based VQE algorithms in ground-state computations on
a range of molecules. We find that, in the presence of noise: (i) ADAPT-VQEs
that construct ansatz circuits iteratively outperform VQEs that use "fixed"
ansatz circuits; and (ii) ADAPT-VQEs perform better when circuits are
constructed from gate-efficient elements rather than physically-motivated ones.
Our results show that, for a wide range of molecules, even the best-performing
VQE algorithms require gate-error probabilities on the order of to
to reach chemical accuracy. This is significantly below the
fault-tolerance thresholds of most error-correction protocols. Further, we
estimate that the maximum allowed gate-error probability scales inversely with
the number of noisy (two-qubit) gates. Our results indicate that useful
chemistry calculations with current gate-based VQEs are unlikely to be
successful on near-term hardware without error correction.Comment: 17 pages, 8 figure
Eccentricity Evolution in Simulated Galaxy Clusters
Strong cluster eccentricity evolution for has appeared in a
variety of observational data sets. We examine the evolution of eccentricity in
simulated galaxy clusters using a variety of simulation methodologies,
amplitude normalizations, and background cosmologies. We do not find find such
evolution for in any of our simulation ensembles. We suggest a
systematic error in the form of a redshift-dependent selection effect in
cluster catalogs or missing physics in cluster simulations important enough to
modify the cluster morphology.Comment: Revised version to be published in ApJ. Moderate revisions, including
additional N-body simulations with varying amplitude normalization and
background matter density within OCDM and CDM scenarios reinforce
our conclusion that observed clusters have recently relaxed much more rapidly
than simulated one
Projection, Spatial Correlations, and Anisotropies in a Large and Complete Sample of Abell Clusters
An analysis of R >= 1 Abell clusters is presented for samples containing
recent redshifts from the MX Northern Abell Cluster Survey. The newly obtained
redshifts from the MX Survey as well as those from the ESO Nearby Abell Cluster
Survey (ENACS) provide the necessary data for the largest magnitude-limited
correlation analysis of rich clusters in the entire sky (excluding the galactic
plane) to date. We find 19.4 <= r_0 <= 23.3 h^-1Mpc, -1.92 <= gamma <= -1.83
for four different subsets of Abell/ACO clusters, including a large sample
(N=104) of cD clusters. We have used this dataset to look for line-of-sight
anisotropies within the Abell/ACO catalogs. We show that the strong
anisotropies present in previously studied Abell cluster datasets are not
present in our R >= 1 samples. There are, however, indications of residual
anisotropies which we show are the result of two elongated superclusters, Ursa
Majoris and Corona Borealis, whose axes lie near the line-of-sight. After
rotating these superclusters so that their semi-major axes are prependicular to
the line-of-sight, we find no anisotropies as indicated by the correlation
function. The amplitude and slope of the two-point correlation function remain
the same before and after these rotations. We also remove a subset of R = 1
Abell/ACO clusters that show sizable foreground/background galaxy contamination
and again find no change in the amplitude or slope of the correlation function.
We conclude that the correlation length of R >= 1 Abell clusters is not
artificially enhanced by line-of-sight anisotropies.Comment: 37 pages, 8 figures, AASTeX Accepted for publication in Ap
Methodological problem with comparing increases in different measures of body weight
<p>Abstract</p> <p>Background</p> <p>A number of studies have compared proportional increases over time in waist circumference (WC) and body mass index (BMI). However this method is flawed. Here, we explain why comparisons of WC and BMI must take into account the relationship between them. We used data from two cross-sectional US surveys (NHANES 1988-94 and 2005-06), and calculated the percentage change in the average BMI and the average WC between the two surveys, comparing the results with a regression analysis of changes in WC relative to BMI.</p> <p>Findings</p> <p>The crude percentage change in BMI (5.8%) was marginally greater than for WC (5.1%). But these percentages cannot be directly compared, as the relationship between the measures is described by a regression equation with an intercept term that does not equal zero. The coefficient of time from the regression equation will determine whether or not WC is on average larger for a given BMI at the second compared with the first time point.</p> <p>Conclusion</p> <p>Differences in the percentage change in WC and the percentage change in BMI cannot be usefully directly compared. Comparisons of increases in the two measures must account for the relationship between them as described by the regression equation.</p
Precision Electron-Beam Polarimetry using Compton Scattering at 1 GeV
We report on the highest precision yet achieved in the measurement of the
polarization of a low energy, (1 GeV), electron beam, accomplished
using a new polarimeter based on electron-photon scattering, in Hall~C at
Jefferson Lab. A number of technical innovations were necessary, including a
novel method for precise control of the laser polarization in a cavity and a
novel diamond micro-strip detector which was able to capture most of the
spectrum of scattered electrons. The data analysis technique exploited track
finding, the high granularity of the detector and its large acceptance. The
polarization of the A, ~GeV electron beam was measured with a
statistical precision of ~1\% per hour and a systematic uncertainty of
0.59\%. This exceeds the level of precision required by the \qweak experiment,
a measurement of the vector weak charge of the proton. Proposed future
low-energy experiments require polarization uncertainty ~0.4\%, and this
result represents an important demonstration of that possibility. This
measurement is also the first use of diamond detectors for particle tracking in
an experiment.Comment: 9 pages, 7 figures, published in PR
A Plasmodium falciparum S33 proline aminopeptidase is associated with changes in erythrocyte deformability
Infection with the apicomplexan parasite Plasmodium falciparum is a major cause of morbidity and mortality worldwide. One of the Striking features of this parasite is its ability to remodel and decrease the deformability of host red blood cells, a process that contributes to disease. To further understand the virulence of Pf we investigated the biochemistry and function of a putative Pf S33 proline aminopeptidase (PJPAP). Unlike other P. falciparum aminopeptidases, PJPAP contains a predicted protein export element that is non-syntenic with other human infecting Plasmodium species. Characterization of PJPAP demonstrated that it is exported into the host red blood cell and that it is a prolyl aminopeptidase with a preference for N-terminal proline substrates. In addition genetic deletion of this exopeptidase was shown to lead to an increase in the deformability of parasite-infected red cells and in reduced adherence to the endothelial cell receptor CD36 under flow conditions. Our studies suggest that PJPAP plays a role in the rigidification and adhesion of infected red blood cells to endothelial surface receptors, a role that may make this protein a novel target for anti-disease interventions strategies. (C) 2016 Elsevier Inc. All rights reserved
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