Three steps towards metrological traceability for ballistics signature measurements.

Abstract The National Institute of Standards and Technology (NIST) in collaboration with the Bureau of Alcohol, Tobacco, Firearms, and Explosives (ATF) has developed the Standard Reference Material (SRM) bullets and casings. NIST and ATF are proposing to establish a National Ballistics Measurement Traceability and Quality System for ballistics signature measurements and correlations using these materials. In this paper, three key steps towards metrological traceability for ballistics signature measurements are discussed that include: 1) Establishing a reference standard; 2) Establishing an unbroken chain of calibrations; and 3) Evaluating measurement uncertainty

Nonlinear Integer Programming

Research efforts of the past fifty years have led to a development of linear integer programming as a mature discipline of mathematical optimization. Such a level of maturity has not been reached when one considers nonlinear systems subject to integrality requirements for the variables. This chapter is dedicated to this topic. The primary goal is a study of a simple version of general nonlinear integer problems, where all constraints are still linear. Our focus is on the computational complexity of the problem, which varies significantly with the type of nonlinear objective function in combination with the underlying combinatorial structure. Numerous boundary cases of complexity emerge, which sometimes surprisingly lead even to polynomial time algorithms. We also cover recent successful approaches for more general classes of problems. Though no positive theoretical efficiency results are available, nor are they likely to ever be available, these seem to be the currently most successful and interesting approaches for solving practical problems. It is our belief that the study of algorithms motivated by theoretical considerations and those motivated by our desire to solve practical instances should and do inform one another. So it is with this viewpoint that we present the subject, and it is in this direction that we hope to spark further research.Comment: 57 pages. To appear in: M. J\"unger, T. Liebling, D. Naddef, G. Nemhauser, W. Pulleyblank, G. Reinelt, G. Rinaldi, and L. Wolsey (eds.), 50 Years of Integer Programming 1958--2008: The Early Years and State-of-the-Art Surveys, Springer-Verlag, 2009, ISBN 354068274

A Survey of Some Methods for Real Quantifier Elimination, Decision, and Satisfiability and Their Applications

International audienceEffective quantifier elimination procedures for first-order theories provide a powerful tool for genericallysolving a wide range of problems based on logical specifications. In contrast to general first-order provers, quantifierelimination procedures are based on a fixed set of admissible logical symbolswith an implicitly fixed semantics. Thisadmits the use of sub-algorithms from symbolic computation. We are going to focus on quantifier elimination forthe reals and its applications giving examples from geometry, verification, and the life sciences. Beyond quantifierelimination we are going to discuss recent results with a subtropical procedure for an existential fragment of thereals. This incomplete decision procedure has been successfully applied to the analysis of reaction systems inchemistry and in the life sciences

Toxicity of two representative petroleum hydrocarbons, toluene and phenanthrene, to five Atlantic coral species

Coral reefs are keystone coastal ecosystems that can be exposed to petroleum hydrocarbons from multiple sources, and when selecting spill response methods to limit environmental damages, corals represent one of the highest valued resources for protection. Because previous research to characterize the sensitivity of coral species to petroleum hydrocarbon exposures is limited, a continuous-flow passive dosing system and toxicity testing protocol was designed to evaluate the acute effects of two representative petroleum compounds, toluene and phenanthrene, on five coral species: Acropora cervicornis, Porites astreoides, Siderastera siderea, Stephanocoenia intersepta, and Solenastrea bournoni. Using analytically confirmed exposures, sublethal and lethal endpoints were calculated for each species, and used as model inputs to determine critical target lipid body burdens (CTLBBs) for characterizing species sensitivity. Further, quantification of the time-dependent toxicity of single hydrocarbon exposures is described to provide model inputs for improved simulation of spill impacts to corals in coastal tropical environments

Preclinical efficacy studies of Influenza A haemagglutinin precursor cleavage loop peptides as a potential vaccine

A universal influenza vaccine that does not require annual reformulation would have clear advantages over the currently approved seasonal vaccine. In this study, we combined the mucosal adjuvant alpha-galactosylceramide (αGalCer) and peptides designed across the highly conserved influenza precursor haemagglutinin (HA0) cleavage loop as a vaccine. Peptides designed across the HA0 of influenza A/H3N2 viruses, delivered to mice via the intranasal route with αGalCer as an adjuvant, provided 100 % protection following H3N2 virus challenge. Similarly, intranasal inoculation of peptides across the HA0 of influenza A/H5N1 with αGalCer completely protected mice against heterotypic challenge with H3N2 virus. Our data suggest that these peptide vaccines effectively inhibited subsequent influenza A/H3N2 virus replication. In contrast, only 20 % of mice vaccinated with αGalCer-adjuvanted peptides spanning the HA0 of H5N1 survived homologous viral challenge, possibly because the HA0 of this virus subtype is cleaved by intracellular furin-like enzymes. Results of these studies demonstrated that HA0 peptides adjuvanted with αGalCer have the potential to form the basis of a synthetic, intranasal influenza vaccine.Darren S. Miller, John Finnie, Timothy R. Bowden, Anita C. Scholz, Sawyin Oh, Tuckweng Kok, Christopher J. Burrell, Lee Trinidad, David B. Boyle and Peng L

Characterization of surface texture-measuring optical microscopes using a binary pseudo-random array standard

Accurate topography measurements of engineered surfaces over a wide range of spatial frequencies are required in many applications. The instrument transfer function (ITF) of the microscope used to characterize the surface topography must be taken into consideration to ensure that the height, or depth, of features with higher spatial frequency content is not underestimated. This applies especially when comparing surface topography measurements made by different types of microscopes. We discuss ITF measurements of a confocal microscope and an interferometric microscope using a binary pseudo-random array (BPRA) standard. BPRA standards are surfaces designed to have constant inherent power spectral density (PSD) over the spatial frequency passband of a microscope. The ITF of a microscope can thus be derived from a PSD measurement of a BPRA standard in a straight-forward manner. We further show how BPRA standards can be used as efficient diagnostic tools to characterize aspects of the imaging performance of topography-measuring microscopes