7,044 research outputs found

    As-built design specification for Boundary Detection And Registration Program (BDARP1)

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    There are no author-identified significant results in this report

    Earth Observations Division version of the Laboratory for Applications of Remote Sensing System (EOD-LARSYS) user guide for the IBM 370/148. Volume 2: User reference manual

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    This document presents instructions for analysts who use the EOD-LARSYS as programmed on the Purdue University IBM 370/148 (recently replaced by the IBM 3031) computer. It presents sample applications, control cards, and error messages for all processors in the system and gives detailed descriptions of the mathematical procedures and information needed to execute the system and obtain the desired output. EOD-LARSYS is the JSC version of an integrated batch system for analysis of multispectral scanner imagery data. The data included is designed for use with the as built documentation (volume 3) and the program listings (volume 4). The system is operational from remote terminals at Johnson Space Center under the virtual machine/conversational monitor system environment

    Discovery of Two High-Magnetic-Field Radio Pulsars

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    We report the discovery of two young isolated radio pulsars with very high inferred magnetic fields. PSR J1119-6127 has period P = 0.407 s, and the largest period derivative known among radio pulsars, Pdot = 4.0e-12. Under standard assumptions these parameters imply a characteristic spin-down age of only tau = 1.6 kyr and a surface dipole magnetic field strength of B = 4.1e13 G. We have measured a stationary period-second-derivative for this pulsar, resulting in a braking index of n = 2.91+-0.05. We have also observed a glitch in the rotation of the pulsar, with fractional period change Delta_P/P = -4.4e-9. Archival radio imaging data suggest the presence of a previously uncataloged supernova remnant centered on the pulsar. The second pulsar, PSR J1814-1744, has P = 3.975 s and Pdot = 7.4e-13. These parameters imply tau = 85 kyr, and B = 5.5e13 G, the largest of any known radio pulsar. Both PSR J1119-6127 and PSR J1814-1744 show apparently normal radio emission in a regime of magnetic field strength where some models predict that no emission should occur. Also, PSR J1814-1744 has spin parameters similar to the anomalous X-ray pulsar (AXP) 1E 2259+586, but shows no discernible X-ray emission. If AXPs are isolated, high magnetic field neutron stars (``magnetars''), these results suggest that their unusual attributes are unlikely to be merely a consequence of their very high inferred magnetic fields.Comment: 7 pages, 3 embedded EPS figures, to be published in Ap

    Electric-field noise from carbon-adatom diffusion on a Au(110) surface: first-principles calculations and experiments

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    The decoherence of trapped-ion quantum gates due to heating of their motional modes is a fundamental science and engineering problem. This heating is attributed to electric-field noise arising from the trap-electrode surfaces. In this work, we investigate the source of this noise by focusing on the diffusion of carbon-containing adsorbates on the surface of Au(110). We show by density functional theory, based on detailed scanning probe microscopy, how the carbon adatom diffusion on the gold surface changes the energy landscape, and how the adatom dipole moment varies with the diffusive motion. A simple model for the diffusion noise, which varies quadratically with the variation of the dipole moment, qualitatively reproduces the measured noise spectrum, and the estimate of the noise spectral density is in accord with measured values.Comment: 8 pages, 6 figure

    Sampling Distributions of Random Electromagnetic Fields in Mesoscopic or Dynamical Systems

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    We derive the sampling probability density function (pdf) of an ideal localized random electromagnetic field, its amplitude and intensity in an electromagnetic environment that is quasi-statically time-varying statistically homogeneous or static statistically inhomogeneous. The results allow for the estimation of field statistics and confidence intervals when a single spatial or temporal stochastic process produces randomization of the field. Results for both coherent and incoherent detection techniques are derived, for Cartesian, planar and full-vectorial fields. We show that the functional form of the sampling pdf depends on whether the random variable is dimensioned (e.g., the sampled electric field proper) or is expressed in dimensionless standardized or normalized form (e.g., the sampled electric field divided by its sampled standard deviation). For dimensioned quantities, the electric field, its amplitude and intensity exhibit different types of Bessel KK sampling pdfs, which differ significantly from the asymptotic Gauss normal and χ2p(2)\chi^{(2)}_{2p} ensemble pdfs when ν\nu is relatively small. By contrast, for the corresponding standardized quantities, Student tt, Fisher-Snedecor FF and root-FF sampling pdfs are obtained that exhibit heavier tails than comparable Bessel KK pdfs. Statistical uncertainties obtained from classical small-sample theory for dimensionless quantities are shown to be overestimated compared to dimensioned quantities. Differences in the sampling pdfs arising from de-normalization versus de-standardization are obtained.Comment: 12 pages, 15 figures, accepted for publication in Phys. Rev. E, minor typos correcte

    Growth and Survival of Perchlorate-Reducing Bacteria in Media Containing Elevated Perchlorate Concentrations and UV-C Conditions

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    Introduction: The identification of perchlorate (ClO4(-)) on Mars has led to the possibility that complete redox couples are available for microbial metabolism in contemporary surface environments. Perchlorate-reducing bacteria (PRB) utilize ClO4(-) and chlorate (ClO3(-)) as terminal electron acceptors due to the high reduction potential. Additionally, ClO4(-) salts have been suggested as a possible source of brines on Mars and spectral evidence indicates that the hydration of ClO4(-) salts in the regolith of Martian is linked to the surface recurring slope lineae (RSL). For these reasons PRB may serve as analog organisms for possible life on Mars. However, there is very little information on the viability of PRB in aqueous environments that contain high levels of perchlorate Microorganisms on or near the surface of Mars, such as in the RSL, would potentially be exposed to high-salinity and high ultraviolet radiation environments. Under these extreme conditions, microorganisms must possess mechanisms for maintaining continued high genome fidelity. To assess possible microbial viability in contemporary Mars analog environments we are investigating the tolerance of two PRB strains in aqueous conditions under high UV-C conditions and high ClO4(-) concentrations

    Exhaustive generation of kk-critical H\mathcal H-free graphs

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    We describe an algorithm for generating all kk-critical H\mathcal H-free graphs, based on a method of Ho\`{a}ng et al. Using this algorithm, we prove that there are only finitely many 44-critical (P7,Ck)(P_7,C_k)-free graphs, for both k=4k=4 and k=5k=5. We also show that there are only finitely many 44-critical graphs (P8,C4)(P_8,C_4)-free graphs. For each case of these cases we also give the complete lists of critical graphs and vertex-critical graphs. These results generalize previous work by Hell and Huang, and yield certifying algorithms for the 33-colorability problem in the respective classes. Moreover, we prove that for every tt, the class of 4-critical planar PtP_t-free graphs is finite. We also determine all 27 4-critical planar (P7,C6)(P_7,C_6)-free graphs. We also prove that every P10P_{10}-free graph of girth at least five is 3-colorable, and determine the smallest 4-chromatic P12P_{12}-free graph of girth five. Moreover, we show that every P13P_{13}-free graph of girth at least six and every P16P_{16}-free graph of girth at least seven is 3-colorable. This strengthens results of Golovach et al.Comment: 17 pages, improved girth results. arXiv admin note: text overlap with arXiv:1504.0697

    Tight local approximation results for max-min linear programs

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    In a bipartite max-min LP, we are given a bipartite graph \myG = (V \cup I \cup K, E), where each agent v∈Vv \in V is adjacent to exactly one constraint i∈Ii \in I and exactly one objective k∈Kk \in K. Each agent vv controls a variable xvx_v. For each i∈Ii \in I we have a nonnegative linear constraint on the variables of adjacent agents. For each k∈Kk \in K we have a nonnegative linear objective function of the variables of adjacent agents. The task is to maximise the minimum of the objective functions. We study local algorithms where each agent vv must choose xvx_v based on input within its constant-radius neighbourhood in \myG. We show that for every ϵ>0\epsilon>0 there exists a local algorithm achieving the approximation ratio ΔI(1−1/ΔK)+ϵ{\Delta_I (1 - 1/\Delta_K)} + \epsilon. We also show that this result is the best possible -- no local algorithm can achieve the approximation ratio ΔI(1−1/ΔK){\Delta_I (1 - 1/\Delta_K)}. Here ΔI\Delta_I is the maximum degree of a vertex i∈Ii \in I, and ΔK\Delta_K is the maximum degree of a vertex k∈Kk \in K. As a methodological contribution, we introduce the technique of graph unfolding for the design of local approximation algorithms.Comment: 16 page
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