Science.gov

Sample records for lattice site location

  1. Lattice site location and annealing behavior of implanted Ca and Sr in GaN

    NASA Astrophysics Data System (ADS)

    De Vries, B.; Vantomme, A.; Wahl, U.; Correia, J. G.; Araújo, J. P.; Lojkowski, W.; Kolesnikov, D.

    2006-07-01

    We report on the lattice location of ion-implanted Ca and Sr in thin films of single-crystalline wurtzite GaN. Using the emission channeling technique the angular distributions of β- particles emitted by the radioactive isotopes 45Ca (t1/2=163.8 d) and 89Sr (t1/2=50.53 d) were monitored with a position-sensitive detector following 60 keV room-temperature implantation. Our experiments give direct evidence that ˜90% of Ca and >60% of Sr atoms were occupying substitutional Ga sites with root mean square displacements of the order of 0.15-0.30 Å, i.e., larger than the expected thermal vibration amplitude of 0.074 Å. Annealing the Ca implanted samples at 1100-1350 °C in high-pressure N2 atmosphere resulted in a better incorporation into the substitutional Ga site. The Sr implanted sample showed a small decrease in rms displacements for vacuum annealing up to 900 °C, while the substitutional fraction remained nearly constant. The annealing behavior of the rms displacements can explain why annealing temperatures above 1100 °C are needed to achieve electrical and optical activations, despite the fact that the majority of the acceptors are already located on Ga sites immediately after ion implantation.

  2. Effect of AlN content on the lattice site location of terbium ions in Al x Ga1-x N compounds

    NASA Astrophysics Data System (ADS)

    Fialho, M.; Rodrigues, J.; Magalhães, S.; Correia, M. R.; Monteiro, T.; Lorenz, K.; Alves, E.

    2016-03-01

    Terbium lattice site location and optical emission in Tb implanted Al x Ga1-x N (0 ≤ x ≤ 1) samples grown by halide vapour phase epitaxy on (0001) sapphire substrates are investigated as a function of AlN content. The samples were implanted with a fluence of 5 × 1014 cm-2 of terbium ions and an energy of 150 keV. Lattice implantation damage is reduced using channelled ion implantation performed along the <0001> axis, normal to the sample surface. Afterwards, thermal annealing treatments at 1400 °C for GaN and 1200 °C for samples with x > 0 were performed to reduce the damage and to activate the optical emission of Tb3+ ions. The study of lattice site location is achieved measuring detailed angular ion channelling scans across the <0001>, < 10\\bar{1}1> and < \\bar{2}113> axial directions. The precise location of the implanted Tb ions is obtained by combining the information of these angular scans with simulations using the Monte Carlo code FLUX. In addition to a Ga/Al substitutional fraction and a random fraction, a fraction of Tb ions occupying a site displaced by 0.2 Å along c-axis from the Ga/Al substitutional site was considered, giving a good agreement between the experimental results and the simulation. Photoluminescence studies proved the optical activation of Tb3+ after thermal annealing and the enhancement of the 5D4 to 7F6 transition intensity with increasing AlN content.

  3. Investigation on the lattice site location of the excess arsenic atoms in GaAs layers grown by low temperature molecular beam epitaxy

    SciTech Connect

    Yu, Kin Man; Liliental-Weber, Z.

    1991-11-01

    We have measured the excess As atoms present in gaze layers grown by molecular beam epitaxy at low substrate temperatures using particle induced x-ray emission technique. The amount of excess As atoms in layers grown by MBE at 200{degrees}C were found to be {approximately} 4 {times} 10{sup 20} cm{sup {minus}2}. Subsequent annealing of the layers under As overpressure at 600{degrees}C did not result in any substantial As loss. However, transmission electron microscopy revealed that As precipitates (2-5nm in diameter) were present in the annealed layers. The lattice location of the excess As atoms in the as grown layers was investigated by ion channeling methods. Angular scans were performed in the <110> axis of the crystal. Our results strongly suggest that a large fraction of these excess As atoms are located in an interstitial position close to an As row. These As intersitials'' are located at a site slightly displaced from the tetrahedral site in a diamond cubic lattice. No interstitial As signal is observed in the annealed layers.

  4. Investigation on the lattice site location of the excess arsenic atoms in GaAs layers grown by low temperature molecular beam epitaxy

    SciTech Connect

    Yu, Kin Man; Liliental-Weber, Z.

    1991-11-01

    We have measured the excess As atoms present in gaze layers grown by molecular beam epitaxy at low substrate temperatures using particle induced x-ray emission technique. The amount of excess As atoms in layers grown by MBE at 200{degrees}C were found to be {approximately} 4 {times} 10{sup 20} cm{sup {minus}2}. Subsequent annealing of the layers under As overpressure at 600{degrees}C did not result in any substantial As loss. However, transmission electron microscopy revealed that As precipitates (2-5nm in diameter) were present in the annealed layers. The lattice location of the excess As atoms in the as grown layers was investigated by ion channeling methods. Angular scans were performed in the <110> axis of the crystal. Our results strongly suggest that a large fraction of these excess As atoms are located in an interstitial position close to an As row. These As ``intersitials`` are located at a site slightly displaced from the tetrahedral site in a diamond cubic lattice. No interstitial As signal is observed in the annealed layers.

  5. Site location of Al-dopant in ZnO lattice by exploiting the structural and optical characterisation of ZnO:Al thin films

    NASA Astrophysics Data System (ADS)

    Nakrela, A.; Benramdane, N.; Bouzidi, A.; Kebbab, Z.; Medles, M.; Mathieu, C.

    The zinc oxide thin films, highly transparent, doped aluminium were prepared on glass substrates by the reactive chemical spray method. The incorporation nature of Al atoms in the ZnO lattice was determined by X-ray diffraction and optical analyses. Indeed, for low doping ⩽2%, the results of X-ray spectra analysis show a simultaneous reduction of lattice parameters (a and c), this variation, which follows VEGARD's law, tends to indicate a substitution of Zn by Al. By against for doping >2% the increase in the lattice parameters thus the grain sizes, in accordance with the VEGARD's law can be explained by occupation of the interstitial sites by Al atoms. Beyond 4%, the material tends to get disorderly and the crystallites orientation is random. The studied optical properties show that the variation of the optical gap follows a law of the x3/2 form for x < 3% (x is the aluminium atom fraction incorporated in the ZnO lattice). The granular structure is fairly visible and some local growths are disrupted. The crystallite size at low enlargement is coherent with the XRD results.

  6. Lattice site of helium implanted in magnesium aluminate spinel

    NASA Astrophysics Data System (ADS)

    Alien, W. R.

    1993-01-01

    The lattice site of helium implanted at 60 keV in magnesium aluminate spinel (MgAl 2O 4) has been investigated with channeling effect measurements that apply the ion-induced 3He(d, p) 4He nuclear reaction. Within the spinel crystal structure, numerous interstices characterized by octahedral anion coordination are intrinsically unfilled by cations. For implantation at 300 K, a typical helium atom locates centrally in one of these vacant octahedral interstices with a probability of approximately 95%. Significant occupation of other lattice sites of either high or low symmetry was rejected. In particular, helium neither clusters in defect complexes nor locates in tetrahedral interstices or substitutional sites.

  7. 9. SITE MAP HIGHLIGHTING SIGNIFICANT BUILDINGS AND SHOWING LOCATION LOCATION ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    9. SITE MAP HIGHLIGHTING SIGNIFICANT BUILDINGS AND SHOWING LOCATION LOCATION OF OUTPATIENT CLINIC ADDITION - U.S. Veterans Administration Medical Center, 600 South Seventieth Street, Lincoln, Lancaster County, NE

  8. statement of significance, location map, site plan, landscape plan, site ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    statement of significance, location map, site plan, landscape plan, site sections, evolution of cemetery landscape. - San Francisco National Cemetery, 1 Lincoln Boulevard, San Francisco, San Francisco County, CA

  9. LOCATIONS OF MILITARY WASTE SITES IN ALASKA

    EPA Science Inventory

    This map shows locations of contaminated and non-contaminated military waste sites, Alaska Native Villages, Native Corporation boundaries, and Traditional Land-Use areas (Artic Slope region only). The entire state is shown plus identification of all military sites currently being...

  10. Precise lattice location of substitutional and interstitial Mg in AlN

    SciTech Connect

    Amorim, L. M.; Pereira, L. M. C.; Decoster, S.; Temst, K.; Vantomme, A.; Wahl, U.; Correia, J. G.; Silva, D. J.; Silva, M. R. da; Gottberg, A.

    2013-12-23

    The lattice site location of radioactive {sup 27}Mg implanted in AlN was determined by means of emission channeling. The majority of the {sup 27}Mg was found to substitute for Al, yet significant fractions (up to 33%) were also identified close to the octahedral interstitial site. The activation energy for interstitial Mg diffusion is estimated to be between 1.1 eV and 1.7 eV. Substitutional Mg is shown to occupy ideal Al sites within a 0.1 Å experimental uncertainty. We discuss the absence of significant displacements from ideal Al sites, in the context of the current debate, on Mg doped nitride semiconductors.

  11. Nanometer-Size Effect on Hydrogen Sites in Palladium Lattice.

    PubMed

    Akiba, Hiroshi; Kofu, Maiko; Kobayashi, Hirokazu; Kitagawa, Hiroshi; Ikeda, Kazutaka; Otomo, Toshiya; Yamamuro, Osamu

    2016-08-17

    Nanometer-sized materials attract much attention because their physical and chemical properties are substantially different from those of bulk materials owing to their size and surface effects. In this work, neutron powder diffraction experiments on the nanoparticles of palladium hydride, which is the most popular metal hydride, have been performed at 300, 150, and 44 K to investigate the positions of the hydrogen atoms in the face-centered cubic (fcc) lattice of palladium. We used high-quality PdD0.363 nanocrystals with a diameter of 8.0 ± 0.9 nm. The Rietveld analysis revealed that 30% of D atoms are located at the tetrahedral (T) sites and 70% at the octahedral (O) sites. In contrast, only the O sites are occupied in bulk palladium hydride and in most fcc metal hydrides. The temperature dependence of the T-site occupancy suggested that the T-sites are occupied only in a limited part, probably in the subsurface region, of the nanoparticles. This is the first study to determine the hydrogen sites in metal nanoparticles. PMID:27462875

  12. Lattice location of diffused Zn atoms in GaAs and InP single crystals

    SciTech Connect

    Chan, L.Y.; Yu, K.M.; Ben-Tzur, M.; Haller, E.E.; Jaklevic, J.M.; Walukiewicz, W. ); Hanson, C.M. )

    1991-03-01

    We have investigated the saturation phenomenon of the free carrier concentration in {ital p}-type GaAs and InP single crystals doped by zinc diffusion. The free hole saturation occurs at 10{sup 20} cm{sup {minus}3} for GaAs, but the maximum concentration for InP appears at mid 10{sup 18} cm{sup {minus}3}. The difference in the saturation hole concentrations for these materials is investigated by studying the incorporation and the lattice location of the impurity zinc, an acceptor when located on a group III atom site. Zinc is diffused into the III-V wafers in a sealed quartz ampoule. Particle-induced x-ray emission with ion-channeling techniques are employed to determine the exact lattice location of the zinc atoms. We have found that over 90% of all zinc atoms occupy Ga sites in the diffused GaAs samples, while for the InP case, the zinc substitutionality is dependent on the cooling rate of the sample after high-temperature diffusion. For the slowly cooled sample, a large fraction ({similar to}90%) of the zinc atoms form random precipitates of Zn{sub 3}P{sub 2} and elemental Zn. However, when rapidly cooled only 60% of the zinc forms such precipitates while the rest occupies specific sites in the InP. We analyze our results in terms of the amphoteric native defect model. We show that the difference in the electrical activity of the Zn atoms in GaAs and InP is a consequence of the different location of the Fermi level stabilization energy in these two materials.

  13. Lattice location of O18 in ion implanted Fe crystals by Rutherford backscattering spectrometry, channeling and nuclear reaction analysis

    NASA Astrophysics Data System (ADS)

    Vairavel, Mathayan; Sundaravel, Balakrishnan; Panigrahi, Binaykumar

    2016-09-01

    There are contradictory theoretical predictions of lattice location of oxygen interstitial atom at tetrahedral and octahedral interstices in bcc Fe. For validating these predictions, 300 keV O18 ions with fluence of 5 × 1015 ions/cm2 are implanted into bcc Fe single crystals at room temperature and annealed at 400 °C. The Rutherford backscattering spectrometry (RBS) and nuclear reaction analysis (NRA)/channeling measurements are carried out with 850 keV protons. The lattice location of implanted O18 is analysed using the α-particles yield from O18(p,α)N15 nuclear reaction. The tilt angular scans of α-particle yield along <110> and <100> axial directions are performed at room temperature. Lattice location of O18 is found to be at tetrahedral interstitial site by comparing the experimental scan with simulated scans using FLUX7 software.

  14. Lattice Location Determination of Ge in SiC by ALCHEMI

    NASA Astrophysics Data System (ADS)

    Kups, T.; Voelskow, M.; Skorupa, W.; Soueidan, M.; Ferro, G.; Pezoldt, J.

    The incorporation of Ge into cubic and hexagonal silicon carbide is compared for three different doping methods: ion-implantation, molecular beam epitaxy and liquid phase epitaxy. The lattice location of Ge was determined by the transmission electron microscopy based method ALCHEMI (atomic location by channelling enhanced microanalysis). Depending on the method used for incorporation, Ge is able to occupy different silicon carbide lattice locations.

  15. Enumeration of directed site animals on the decorated square lattices

    NASA Astrophysics Data System (ADS)

    Ali, Agha Afsar

    1994-01-01

    We study the problem of directed site lattice animals on decorated square lattice using its equivalence to the probabilistic cellular automata. By mapping this problem to a special case of a triangular Ising model in external field, we prove that the generating function of number of animals satisfy a quadratic equation, as was conjectured by Andrew Conway. The coupling constants of the latter satisfy the disorder condition, and it reduces to a problem already solved by Jaekel and Maillard. We also establish a connection of this problem with the problem of anisotropic directed bond percolation on a square lattice.

  16. Lattice location of deuterium in plasma and gas charged Mg doped GaN

    SciTech Connect

    Wampler, W.R.; Barbour, J.C.; Seager, C.H.; Myers, S.M. Jr.; Wright, A.F.; Han, J.

    1999-12-02

    The authors have used ion channeling to examine the lattice configuration of deuterium in Mg doped GaN grown by MOCVD. The deuterium is introduced both by exposure to deuterium gas and to ECR plasmas. A density functional approach including lattice relaxation, was used to calculate total energies for various locations and charge states of hydrogen in the wurtzite Mg doped GaN lattice. Computer simulations of channeling yields were used to compare results of channeling measurements with calculated yields for various predicted deuterium lattice configurations.

  17. Lattice location and thermal stability of implanted Fe in ZnO

    SciTech Connect

    Rita, E.; Wahl, U.; Correia, J.G.; Alves, E.; Soares, J.C.

    2004-11-22

    The emission channeling technique was applied to evaluate the lattice location of implanted {sup 59}Fe in single-crystalline ZnO. The angular distribution of {beta}{sup -} particles emitted by {sup 59}Fe was monitored with a position-sensitive electron detector, following 60 keV low dose (2.0x10{sup 13} cm{sup -2}) room-temperature implantation of the precursor isotope {sup 59}Mn. The emission patterns around the [0001], [1102],[1101], and [2113] directions revealed that following annealing at 800 deg. C, 95(8)% of the Fe atoms occupy ideal substitutional Zn sites with rms displacements of 0.06-0.09 A.

  18. Lattice location and annealing behaviour of helium atoms implanted in uranium dioxide single crystals

    NASA Astrophysics Data System (ADS)

    Belhabib, T.; Desgardin, P.; Sauvage, T.; Erramli, H.; Barthe, M. F.; Garrido, F.; Carlot, G.; Nowicki, L.; Garcia, P.

    2015-12-01

    Helium behaviour in irradiated uranium dioxide may play an important role in the mechanical stability of nuclear fuels during and after its use in nuclear power plants. Helium migration mechanisms in bulk UO2 have already been the subject of theoretical studies but there is a lack of experimental data relating to the most stable location in the crystal. To this end, we have studied uranium dioxide samples implanted with helium ions at low fluence before and after thermal annealing in the range 600 and 800 °C. UO2 single crystals were implanted with 50 keV-3He ions at the fluence of 1 × 1015 at cm-2 and the location in the lattice of helium atoms was investigated using NRA (Nuclear Reaction Analysis) based on the reaction of 3He with deuterons (3He (d,p) 4He) in a channelling mode, recording angular scans across axes and planes. Furthermore, the uranium sub-lattice was analysed by the classical RBS method. After implantation, the experimental angular scans recorded across the main crystallographic axes and along major planes show that the helium atoms in their large majority occupy octahedral interstitial sites. No modification of the occupied crystallographic site was found after annealing at 600 °C. Conversely, no crystallographic relationship between matrix and helium signals was revealed following annealing at 800 °C. The latter feature is likely related to the clustering of implanted helium atoms into gas-filled bubbles. These experimental results have been quantified and interpreted using Monte Carlo simulations with the McChasy code.

  19. Location of Sites Within 'Cryptic Terrain'

    NASA Technical Reports Server (NTRS)

    2007-01-01

    A regional landscape near Mars' south pole is called 'cryptic terrain' because it once defied explanation, but new observations bolster and refine interpretations of how springtime outbursts of carbon-dioxide gas there sculpt intricate patterns and paint seasonal splotches. This map indicates locations of three sites that have been examined within the area of cryptic terrain, informally designated 'Manhattan,' 'Giza' and 'Ithaca.'

    The underlying map offers context of brightness measurements from the Thermal Emission Spectrometer instrument draped over a shaded relief map based on data from the Mars Orbiter Laser Altimeter instrument. Cool colors are areas with a low albedo (dark) and warm colors are areas which have high albedo (bright). Both of those instruments flew on NASA's Mars Global Surveyor orbiter.

  20. Location, location, location: priority effects in wood decay communities may vary between sites.

    PubMed

    Hiscox, Jennifer; Savoury, Melanie; Johnston, Sarah R; Parfitt, David; Müller, Carsten T; Rogers, Hilary J; Boddy, Lynne

    2016-06-01

    Priority effects are known to have a major influence on fungal community development in decomposing wood, but it has not yet been established whether these effects are consistent between different geographical locations. Here, beech (Fagus sylvatica) wood disks that had been pre-colonized with three wood decay basidiomycetes were placed in seven woodland sites with similar characteristics for 12-24 months, and the successor communities profiled using culture-based techniques coupled with amplicon sequencing. On the majority of sites, assembly history differed as a result of primary versus secondary resource capture only (i.e. different communities developed in uncolonized control disks compared with those that had been pre-colonized), but on certain sites distinct successor communities followed each pre-colonizer species. This study provides preliminary evidence that differences in abiotic factors and species pools between sites can cause spatial variation in how priority effects influence wood decay communities. PMID:26626102

  1. Further development of a facility for channeling studies: application to lattice location

    SciTech Connect

    Lopes, D.R.

    1984-08-01

    Equipment modifications at the Lawrence Berkeley Laboratory (LBL) Rutherford backscattering facility, including the addition of a high precision goniometer, have been made to enhance the performance of channeling experiments. The angular divergence of the alpha particle beam was also reduced to <0.05/sup 0/ by improving the collimation. To demonstrate improved channeling capability angular scans were performed about the (100), (110), and (111) axial channels of a 3400 A (100) silicon membrane. Both the minimum yield, chi/sub min/, and the critical angle, psi/sub 1/2/, were consistent with accepted values. A preliminary investigation of the lattice location of cobalt on the (100) silicon surface was undertaken. Approximately 4.5 x 10/sup 15/ Co atoms/cm/sup 2/ were electron beam deposited on a 3900 A, HF etched silicon membrane in a system using oilless pumps. Preliminary channeling data taken approximately one month later indicated a preferred site for approximately 16% of the cobalt atoms. Channeling data obtained six months later with the new goniometer showed no evidence for a preferred site. Room temperature oxidation between experiments was observed and is thought to have affected the location of the cobalt atoms. 33 references, 15 figures.

  2. Near coincidence site lattice misorientations in monoclinic zirconia

    SciTech Connect

    Gertsman, V.Y.; Zhilyaev, A.P.; Szpunar, J.

    1996-12-01

    Zirconium dioxide, ZrO{sub 2}, exists in three crystalline phases: monoclinic, tetragonal, and cubic. Calculations of the coincidence site lattice (CSL) misorientations for the last two lattices and for hexagonal ones using the methods developed represent little difficulty. However, no procedure for the determination of the CSL misorientations in the monoclinic system has been reported so far. Monoclinic zirconia has the crystallographic space group P2{sub 1}/c and the following parameters of the unit cell (e.g., 5, 6): a = 5.1490 {angstrom}, b = 5.2133 {angstrom}, c = 5.3161 {angstrom}, and {beta} = 99.228{degree}. Before discussing possible CSL misorientations in zirconia, consider a simple example based on geometric considerations. In any monoclinic crystal (with any lattice parameters) the two symmetrical boundaries along the (001) and (100) planes must have highly ordered atomic structure. The misorientation of the first boundary is descried as a rotation of either 180{degree} around the [100] direction or 180{degree} around the normal to the (001) plane. The misorientation of the second boundary is 180{degree} [001] or 180{degree} around the normal to the (100) plane. It can be shown that three-dimensional CSLs will exist in both cases if (c/a)cos{beta} is a rational number. This example justifies the following approximation of the unit cell in the monoclinic zirconia: a = b = c and cos{beta} = {minus}1/6 (i.e., {beta} = 99.594{degree}). Consider the following prismatic cell in the monoclinic crystal structure: ([1 0 1], [{bar 1} 0 1], [0 1 0]). With the above approximation, this cell is orthogonal with the ratios of the squares of the edge lengths expressed as 5:7:3. Therefore, one can apply the algorithm for calculations of the CSL misorientations in orthorhombic lattices with rational ratios of squares of the lattice periods, which is based on the general vector-quaternion method of misorientation representation.

  3. 23. VIEW OF DOG KENNELS LOCATED AT LAUNCH SITE, LOOKING ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    23. VIEW OF DOG KENNELS LOCATED AT LAUNCH SITE, LOOKING NORTH Marilyn Ziemer, photographer, March 1988 - Mount Gleason Nike Missile Site, Angeles National Forest, South of Soledad Canyon, Sylmar, Los Angeles County, CA

  4. Spontaneous symmetry breaking in Schroedinger lattices with two nonlinear sites

    SciTech Connect

    Brazhnyi, Valeriy A.; Malomed, Boris A.

    2011-05-15

    We introduce discrete systems in the form of straight (infinite) and ring-shaped chains, with two symmetrically placed nonlinear sites. The systems can be implemented in nonlinear optics (as waveguiding arrays) and Bose-Einstein condensates (by means of an optical lattice). A full set of exact analytical solutions for symmetric, asymmetric, and antisymmetric localized modes is found, and their stability is investigated in a numerical form. The symmetry-breaking bifurcation, through which the asymmetric modes emerge from the symmetric ones, is found to be of the subcritical type. It is transformed into a supercritical bifurcation if the nonlinearity is localized in relatively broad domains around two central sites, and also in the ring of a small size, i.e., in effectively nonlocal settings. The family of antisymmetric modes does not undergo bifurcations and features both stable and unstable portions. The evolution of unstable localized modes is investigated by means of direct simulations. In particular, unstable asymmetric states, which exist in the case of the subcritical bifurcation, give rise to breathers oscillating between the nonlinear sites, thus restoring an effective dynamical symmetry between them.

  5. Influence of n{sup +} and p{sup +} doping on the lattice sites of implanted Fe in Si

    SciTech Connect

    Silva, D. J.; Araújo, J. P.; Wahl, U.; Correia, J. G.

    2013-09-14

    We report on the lattice location of implanted {sup 59}Fe in n{sup +}- and p{sup +}-type Si by means of emission channeling. We found clear evidence that the preferred lattice location of Fe changes with the doping of the material. While in n{sup +}-type Si Fe prefers displaced bond-centered (BC) sites for annealing temperatures up to 600 °C, changing to ideal substitutional sites above 700 °C, in p{sup +}-type Si, Fe prefers to be in displaced tetrahedral interstitial positions after all annealing steps. The dominant lattice sites of Fe in n{sup +}-type Si therefore seem to be well characterized for all annealing temperatures by the incorporation of Fe into vacancy-related complexes, either into single vacancies which leads to Fe on ideal substitutional sites, or multiple vacancies, which leads to its incorporation near BC sites. In contrast, in p{sup +}-type Si, the major fraction of Fe is clearly interstitial (near-T or ideal T) for all annealing temperatures. The formation and possible lattice sites of Fe in FeB pairs in p{sup +}-Si are discussed. We also address the relevance of our findings for the understanding of the gettering effects caused by radiation damage or P-diffusion, the latter involving n{sup +}-doped regions.

  6. Statement of significance, site location graphic, mantle elevation, section through ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Statement of significance, site location graphic, mantle elevation, section through decorative wall element, and terra cotta details - Boston Architectural College, Terra Cotta Mantel, 951 Boylston Street, Boston, Suffolk County, MA

  7. Floor Plan, Axonometric View, Site Location Key, Cesar Chavez Fasting ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    Floor Plan, Axonometric View, Site Location Key, Cesar Chavez Fasting Room Diagram - Forty Acres, Tomasa Zapata Mireles Co-op Building , 30168 Garces Highway (Northwest Corner of Garces Highway and Mettler Avenue), Delano, Kern County, CA

  8. 58. photographer unknown undated TWO POTHOLES LOCATED AT POWERHOUSE SITE, ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    58. photographer unknown undated TWO POTHOLES LOCATED AT POWERHOUSE SITE, TO BE FILLED WITH CONCRETE. - Bonneville Project, Powerhouse No.1, Spanning Bradford Slough, from Bradford Island, Bonneville, Multnomah County, OR

  9. A GIS approach for predicting prehistoric site locations.

    SciTech Connect

    Kuiper, J. A.; Wescott, K. L.

    1999-08-04

    Use of geographic information system (GIS)-based predictive mapping to locate areas of high potential for prehistoric archaeological sites is becoming increasingly popular among archaeologists. Knowledge of the environmental variables influencing activities of original inhabitants is used to produce GIS layers representing the spatial distribution of those variables. The GIS layers are then analyzed to identify locations where combinations of environmental variables match patterns observed at known prehistoric sites. Presented are the results of a study to locate high-potential areas for prehistoric sites in a largely unsurveyed area of 39,000 acres in the Upper Chesapeake Bay region, including details of the analysis process. The project used environmental data from over 500 known sites in other parts of the region and the results corresponded well with known sites in the study area.

  10. Environmental assessment overview, Reference repository location, Hanford site, Washington

    SciTech Connect

    none,

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified a reference repository location at the Hanford Site in Washington as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. The site is in the Columbia Plateau, which is one of five distinct geohydrologic settings considered for the first repository. To determine their suitability, the Hanford site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. On the basis of the evaluations reported in this EA, the DOE has found that the Hanford site is not disqualified under the guidelines. On the basis of these findings, the DOE is nominating the Hanford site as one of five sites suitable for characterization. 3 figs.

  11. Location, location, location: small shifts in collection site result in large intraspecific differences in macroalgal palatability

    NASA Astrophysics Data System (ADS)

    Keeley, Kathryn N.; Stroh, Jolie D.; Tran, Diem Samantha C.; Fong, Caitlin R.; Fong, Peggy

    2015-06-01

    The role of herbivorous fishes in coral reef resilience has increased interest in the process of herbivory and has focused attention on herbivore feeding behavior, making it important to evaluate experimental methods used to assess herbivore decisions. We tested whether small-scale differences in collection site play a role in within-species palatability of macroalgae. Baseline grazing assays using algae collected on a fringing reef in Moorea, French Polynesia, revealed that herbivore preferences among three common species ranked Padina boryana > Sargassum mangarevense ≫ Amansia rhodantha. Comparing grazing preferences between individual thalli of the same species collected <15 m apart revealed that consumption of intertidal S. mangarevense was nearly six times greater than for conspecifics collected from the adjacent subtidal reef flat. The same trend occurred for P. boryana but was not significant. This demonstrated that algal palatability can vary on a very small spatial scale, presenting a potential trap for the unwary when setting up experiments; we encourage researchers to consider this potential complication in experimental studies of herbivory.

  12. Landing site locating of UAV by SIFT matching

    NASA Astrophysics Data System (ADS)

    Zhang, Xiaomiao; Liu, Xiaolin; Yu, Qifeng

    2008-03-01

    To achieve the landing site locating, the proof-of-concept strategy demands a reference image captured beforehand. This strategy adopts the way of wide-baseline matching between images from the airborne camera and the reference image. First of all, a proof-of-concept strategy of vision-aided landing area locating of unmanned aerial vehicle is presented. Then, there are mainly two algorithms under discussion. One is landing site finding using SIFT based wide-baseline match, and the experiment results show that is qualified to finding landing site. The other is landing site locating by camera position measurement based on the feature point with known world coordinates. Assuming that the airborne camera has been calibrated off-line, with known intrinsic camera parameters and world coordinates of at least 4 feature points, the position of camera can be roughly estimated. The SIFT feature points of reference image have been selected and their position in world coordination have been marked before wide-baseline matching, so, when matching having been put into practice, world coordinates of matched points in each image captured by airborne camera can be gotten directly. Assuming when landing site locating task is carrying out, the UAV is fairly high, so the landing site could be regarded as planar. And due to the camera is fixed to UAV, the relative position of UAV to the landing site can be measured according the algorithm in this paper, that is to say, providing that at least one image of UAV landing site is offered, the landing site can be successfully located.

  13. Water treatment plant site location using rough set theory.

    PubMed

    Arabani, M; Pirouz, M

    2015-10-01

    Currently, advanced methods have been developed to select an appropriate site for an engineering project. The ability to make a good decision in site selection can help the engineers to reduce the expensive costs, which are very important in large construction projects. In this paper, a new approach for site selection is presented. This method is based on rough set theory which is a mathematical theory presented by professor Pawlak. In this study, the results of the rough set decision-making are compared with the results of the regression method in a practical case study for the site location of a water treatment plant in Ardabil Province in the northwest of Iran, to demonstrate that the rough set theory provides a useful method for site selection. The results of practical studies indicate that using this method for site selection decision-making can reduce costs and prevent hazards that may happen due to civil engineering uncertainties. PMID:27613288

  14. Environmental assessment: Reference repository location, Hanford site, Washington

    SciTech Connect

    none,

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified a reference repository location at the Hanford Site in Washington as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. The site is in the Columbia Plateau, which is one of five distinct geohydrologic settings considered for the first repository. To determine their suitability, the Hanford Site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. On the basis of the evaluations reported in this EA, the DOE has found that the Hanford site is not disqualified under the guidelines. The DOE has also found that it is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Hanford site as one of five sites suitable for characterization.

  15. Environmental assessment: Reference repository location, Hanford site, Washington

    SciTech Connect

    none,

    1986-05-01

    In February 1983, the US Department of Energy (DOE) identified a reference repository location at the Hanford Site in Washington as one of the nine potentially acceptable sites for a mined geologic repository for spent nuclear fuel and high-level radioactive waste. The site is in the Columbia Plateau, which is one of five distinct geohydrologic settings considered for the first repository. To determine their suitability, the Hanford site and the eight other potentially acceptable sites have been evaluated in accordance with the DOE's General Guidelines for the Recommendation of Sites for the Nuclear Waste Repositories. These evaluations were reported in draft environmental assessments (EAs), which were issued for public review and comment. After considering the comments received on the draft EAs, the DOE prepared the final EAs. On the basis of the evaluations reported in this EA, the DOE has found that the Hanford site is not disqualified under the guidelines. The DOE has also found that is is suitable for site characterization because the evidence does not support a conclusion that the site will not be able to meet each of the qualifying conditions specified in the guidelines. On the basis of these findings, the DOE is nominating the Hanford site as one of five sites available for characterization.

  16. Growth of coincident site lattice matched semiconductor layers and devices on crystalline substrates

    DOEpatents

    Norman, Andrew G; Ptak, Aaron J

    2013-08-13

    Methods of fabricating a semiconductor layer or device and said devices are disclosed. The methods include but are not limited to providing a substrate having a crystalline surface with a known lattice parameter (a). The method further includes growing a crystalline semiconductor layer on the crystalline substrate surface by coincident site lattice matched epitaxy, without any buffer layer between the crystalline semiconductor layer and the crystalline surface of the substrate. The crystalline semiconductor layer will be prepared to have a lattice parameter (a') that is related to the substrate lattice parameter (a). The lattice parameter (a') maybe related to the lattice parameter (a) by a scaling factor derived from a geometric relationship between the respective crystal lattices.

  17. 6. Photocopy of Location, Site & Wall Sections drawing (from ...

    Library of Congress Historic Buildings Survey, Historic Engineering Record, Historic Landscapes Survey

    6. Photocopy of Location, Site & Wall Sections drawing (from the Bonneville Power Administration Engineering Vault, Portland, Oregon, Drawing C13-J2-342-D1, Sheet 1, 13 March 1939) - Bonneville Power Administration South Bank Substation, I-84, South of Bonneville Dam Powerhouse, Bonneville, Multnomah County, OR

  18. IMPLICATIONS OF VOCATIONAL EDUCATION FOR PLANT SITE LOCATION.

    ERIC Educational Resources Information Center

    DEAN, ERNEST H.

    THE PURPOSE OF THIS PROJECT WAS TO DETERMINE THE SIGNIFICANCE OF VOCATIONAL-TECHNICAL EDUCATION IN THE MANUFACTURING INDUSTRY PLANT SITE SELECTION PROCESS. FROM A COMPOSITE LISTING OF 619 MANUFACTURING COMPANIES WHICH HAD LOCATED IN COLORADO, NEW MEXICO, ARIZONA, NEVADA, IDAHO, UTAH, AND WYOMING SINCE JANUARY 1960, 116 INTERVIEWS AND 90 COMPLETED…

  19. A Simple Spreadsheet Program for the Calculation of Lattice-Site Distributions

    ERIC Educational Resources Information Center

    McCaffrey, John G.

    2009-01-01

    A simple spreadsheet program is presented that can be used by undergraduate students to calculate the lattice-site distributions in solids. A major strength of the method is the natural way in which the correct number of ions or atoms are present, or absent, at specific lattice distances. The expanding-cube method utilized is straightforward to…

  20. 14 CFR 420.21 - Launch site location review-launch site boundary.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Launch site location review-launch site boundary. 420.21 Section 420.21 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Criteria and Information Requirements for Obtaining a...

  1. Coincident-site lattice matching during van der Waals epitaxy

    PubMed Central

    Boschker, Jos E.; Galves, Lauren A.; Flissikowski, Timur; Lopes, Joao Marcelo J.; Riechert, Henning; Calarco, Raffaella

    2015-01-01

    Van der Waals (vdW) epitaxy is an attractive method for the fabrication of vdW heterostructures. Here Sb2Te3 films grown on three different kind of graphene substrates (monolayer epitaxial graphene, quasi freestanding bilayer graphene and the SiC (6√3 × 6√3)R30° buffer layer) are used to study the vdW epitaxy between two 2-dimensionally (2D) bonded materials. It is shown that the Sb2Te3 /graphene interface is stable and that coincidence lattices are formed between the epilayers and substrate that depend on the size of the surface unit cell. This demonstrates that there is a significant, although relatively weak, interfacial interaction between the two materials. Lattice matching is thus relevant for vdW epitaxy with two 2D bonded materials and a fundamental design parameter for vdW heterostructures. PMID:26658715

  2. Collagen telopeptides (cross-linking sites) play a role in collagen gel lattice contraction

    NASA Technical Reports Server (NTRS)

    Woodley, D. T.; Yamauchi, M.; Wynn, K. C.; Mechanic, G.; Briggaman, R. A.

    1991-01-01

    Solubilized interstitial collagens will form a fibrillar, gel-like lattice when brought to physiologic conditions. In the presence of human dermal fibroblasts the collagen lattice will contract. The rate of contraction can be determined by computer-assisted planemetry. The mechanisms involved in contraction are as yet unknown. Using this system it was found that the rate of contraction was markedly decreased when collagen lacking telopeptides was substituted for native collagen. Histidinohydroxylysinonorleucine (HHL) is a major stable trifunctional collagen cross-link in mature skin that involves a carboxyl terminal, telopeptide site 16c, the sixteenth amino acid residue from the carboxy terminal of the telopeptide region of alpha 1 (I) in type I collagen. Little, if any, HHL was present in native, purified, reconstituted, soluble collagen fibrils from 1% acetic acid-extracted 2-year-old bovine skin. In contrast, HHL cross-links were present (0.22 moles of cross-link per mole of collagen) in lattices of the same collagen contracted by fibroblasts. However, rat tail tendon does not contain HHL cross-links, and collagen lattices made of rat tail tendon collagen are capable of contraction. This suggests that telopeptide sites, and not mature HHL cross-links per se, are essential for fibroblasts to contract collagen lattices. Beta-aminopropionitrile fumarate (BAPN), a potent lathyrogen that perturbs collagen cross-linking by inhibition of lysyl oxidase, also inhibited the rate of lattice cell contraction in lattices composed of native collagen. However, the concentrations of BAPN that were necessary to inhibit the contraction of collagen lattices also inhibited fibroblast growth suggestive of cellular toxicity. In accordance with other studies, we found no inhibition of the rate of lattice contraction when fibronectin-depleted serum was used. Electron microscopy of contracted gels revealed typical collagen fibers with a characteristic axial periodicity. The data

  3. Mars Pathfinder First Anniversary Special -- Refined Landing Site Location

    NASA Technical Reports Server (NTRS)

    1998-01-01

    It has been one year since NASA's Return to the Red Planet began with the spectacular landing of Mars Pathfinder and its microrover, Sojourner. The spacecraft bounced onto a flood-washed landscape on July 4, 1997.

    Mars Pathfinder was soon joined by the orbiting Mars Global Surveyor on September 11, 1997 (PDT). Mars Global Surveyor's high resolution camera, MOC, took a picture of the Mars Pathfinder landing site region during its 256th orbit on April 22, 1998. This picture--at about 5 meters (11 feet) per pixel--is the best available for the site. The previous best images were from the Viking 1 Orbiter in 1976, and had resolutions of about 38 meters (125 feet) per pixel.

    The MOC image has allowed scientists to determine the exact location of the Mars Pathfinder lander. Unfortunately, the image resolution is not good enough to actually see the lander--nor can any of the familiar boulders (e.g., 'Yogi') be seen at this resolution.

    Using the MOC image, the landing site location has been refined by Dr. Michael Malin, Principal Investigator for the Mars Global Surveyor MOC Team and a Participating Scientist on the Mars Pathfinder mission. The images above illustrate how the landing site was located by using the 'sight lines' published by T. Parker (Jet Propulsion Laboratory, Pasadena, CA) and topographic map provided by R. Kirk (U.S. Geological Survey, Flagstaff, AZ).

    Left image: MOC image 25603 subframe, shown at 15 meters (about 50 feet) per pixel resolution. Small, colored box is a topographic map of the Mars Pathfinder landing site produced by the U.S. Geological Survey (Flagstaff, AZ) from Mars Pathfinder stereographic images . Dark, heavy lines are 'sight lines' to various landmarks seen along the horizon in Mars Pathfinder camera images, measured by T. Parker and matched to features seen in Viking Orbiter images. These lines were published in Science, v. 278, p. 1746, December 5, 1997. The lighter, thinner sightlines are the same lines, adjusted to

  4. 43 CFR 3832.42 - How do I locate a tunnel site?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false How do I locate a tunnel site? 3832.42... MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Tunnel Sites § 3832.42 How do I locate a tunnel site? You may locate a tunnel site by: (a) Erecting...

  5. Thymocyte plasma membrane: the location of specific glucocorticoid binding sites

    SciTech Connect

    Sergeev, P.V.; Kalinin, G.V.; Dukhanin, A.S.

    1987-01-01

    In modern molecular endocrinology it is now possible to determine the localization of receptors for biologically active substances with the aid of ligands, with high affinity for the receptor, immobilized on polymers. The purpose of this paper is to study the ability of hydrocortisone (HC), immobilized on polyvinylpyrrolidone (PVP-HC), to reduce binding of tritium-HC by thymocytes of adrenalectomized rats. It is determined that specific binding sites for HC on rat thymocytes are also accessible for PVP-HC, which, due to the fact that this immobilized version of HC does not penetrate into the cell, leads to the conclusion that the binding sites for HC itself are located in the plasma membrane.

  6. Control site location and transcriptional regulation in Escherichia coli.

    PubMed Central

    Collado-Vides, J; Magasanik, B; Gralla, J D

    1991-01-01

    The regulatory regions for 119 Escherichia coli promoters have been analyzed, and the locations of the regulatory sites have been cataloged. The following observations emerge. (i) More than 95% of promoters are coregulated with at least one other promoter. (ii) Virtually all sigma 70 promoters contain at least one regulatory site in a proximal position, touching at least position -65 with respect to the start point of transcription. There are not yet clear examples of upstream regulation in the absence of a proximal site. (iii) Operators within regulons appear in very variable proximal positions. By contrast, the proximal activation sites of regulons are much more fixed. (iv) There is a forbidden zone for activation elements downstream from approximately position -20 with respect to the start of transcription. By contrast, operators can occur throughout the proximal region. When activation elements appear in the forbidden zone, they repress. These latter examples usually involve autoregulation. (v) Approximately 40% of repressible promoters contain operator duplications. These occur either in certain regulons where duplication appears to be a requirement for repressor action or in promoters subject to complex regulation. (vi) Remote operator duplications occur in approximately 10% of repressible promoters. They generally appear when a multiple promoter region is coregulated by cyclic AMP receptor protein. (vii) Sigma 54 promoters do not require proximal or precisely positioned activator elements and are not generally subject to negative regulation. Rationales are presented for all of the above observations. PMID:1943993

  7. Coincident site lattice-matched InGaN on (111) spinel substrates

    SciTech Connect

    Norman, A. G.; Dippo, P. C.; Moutinho, H. R.; Simon, J.; Ptak, A. J.

    2012-04-09

    Coincident site lattice-matched wurtzite (0001) In{sub 0.31}Ga{sub 0.69}N, emitting in the important green wavelength region, is demonstrated by molecular beam epitaxy on a cubic (111) MgAl{sub 2}O{sub 4} spinel substrate. The coincident site lattice matching condition involves a 30 deg. rotation between the lattice of the InGaN epitaxial layer and the lattice of the spinel. This work describes an alternative approach towards realizing more compositionally homogenous InGaN films with low dislocation density emitting in the ''green gap'' of low efficiency currently observed for semiconductor light emitting diodes (LEDs). This approach could lead to higher efficiency green LEDs presently of great interest for solid-state lighting applications.

  8. Coincident Site Lattice Matched InGaN on (111) Spinel Substrates

    SciTech Connect

    Norman, A. G.; Dippo, P. C.; Moutinho, H. R.; Simon, J.; Ptak, A. J.

    2012-04-09

    Coincident site lattice-matched wurtzite (0001) In{sub 0.31}Ga{sub 0.69}N, emitting in the important green wavelength region, is demonstrated by molecular beam epitaxy on a cubic (111) MgAl{sub 2}O{sub 4} spinel substrate. The coincident site lattice matching condition involves a 30{sup o} rotation between the lattice of the InGaN epitaxial layer and the lattice of the spinel. This work describes an alternative approach towards realizing more compositionally homogenous InGaN films with low dislocation density emitting in the 'green gap' of low efficiency currently observed for semiconductor light emitting diodes (LEDs). This approach could lead to higher efficiency green LEDs presently of great interest for solid-state lighting applications.

  9. Tuning magnetic frustration on the diamond lattice of the A-site magnetic spinels CoA12-xGax04: lattice expansion versus site disorder

    SciTech Connect

    Proffen, Thomas E; Melot, Brent C; Page, Katharine; Seshadri, Ramzy; Stoudenmire, E M; Balents, Leon; Bergman, Doron L

    2008-01-01

    The spinels CoB{sub 2}O{sub 4} with magnetic Co{sup 2+} ions on the diamond lattice A site can be frustrated because of competing near-neighbor (J{sub 1}) and next-near neighbor (J{sub 2}) interactions. Here we describe attempts to tune the relative strengths of these interactions by substitution on the non-magnetic B-site. The system we employ is CoAl{sub 2-x}Ga{sub x}O{sub 4}, where Al is systematically replaced by the larger Ga, ostensibly on the B site. As expected, Ga substitution expands the lattice, resulting in Co atoms on the A-site being pushed further from one other and thereby weakening magnetic interactions. In addition, Ga distributes between the B and the A site in a concentration dependent manner displacing an increasing amount of Co from the A site with increasing x. This increased inversion, which is confirmed by neutron diffraction studies carried out at room temperature, affects magnetic ordering very significantly, and changes the nature of the ground state. Modeling of the magnetic coupling illustrates the complexity that arises from the cation site disorder.

  10. Exploiting protein flexibility to predict the location of allosteric sites

    PubMed Central

    2012-01-01

    Background Allostery is one of the most powerful and common ways of regulation of protein activity. However, for most allosteric proteins identified to date the mechanistic details of allosteric modulation are not yet well understood. Uncovering common mechanistic patterns underlying allostery would allow not only a better academic understanding of the phenomena, but it would also streamline the design of novel therapeutic solutions. This relatively unexplored therapeutic potential and the putative advantages of allosteric drugs over classical active-site inhibitors fuel the attention allosteric-drug research is receiving at present. A first step to harness the regulatory potential and versatility of allosteric sites, in the context of drug-discovery and design, would be to detect or predict their presence and location. In this article, we describe a simple computational approach, based on the effect allosteric ligands exert on protein flexibility upon binding, to predict the existence and position of allosteric sites on a given protein structure. Results By querying the literature and a recently available database of allosteric sites, we gathered 213 allosteric proteins with structural information that we further filtered into a non-redundant set of 91 proteins. We performed normal-mode analysis and observed significant changes in protein flexibility upon allosteric-ligand binding in 70% of the cases. These results agree with the current view that allosteric mechanisms are in many cases governed by changes in protein dynamics caused by ligand binding. Furthermore, we implemented an approach that achieves 65% positive predictive value in identifying allosteric sites within the set of predicted cavities of a protein (stricter parameters set, 0.22 sensitivity), by combining the current analysis on dynamics with previous results on structural conservation of allosteric sites. We also analyzed four biological examples in detail, revealing that this simple coarse

  11. Spatial and Temporal Resolution of Three Sites Characterizing Lattice-Assisted Nuclear Reactions (LANR)

    NASA Astrophysics Data System (ADS)

    Swartz, Mitchell

    2008-03-01

    We present developing evidence that three different sites (physical locations in the solid state) are involved in lattice-assisted nuclear reactions (LANR). By expanding the equation first developed by Prof. David Nagel at ICCF-13ootnotetextNagel, D., ``Rates for LENRs at Surfaces'', ICCF-13, we correlate observations of excess heat and de novo helium-4 production to three different physical locations and to the optimal operating points (OOPs) which are now known to characterize LANR systemsootnotetextSwartz. M., G. Verner, ``Excess Heat from Low Electrical Conductivity Heavy Water Spiral-Wound Pd/D2O/Pt and Pd/D2O-PdCl2/Pt Devices'', ICCF-10 (Camb. MA), Proceedings of ICCF-10, (2003).. This observation will be shown to be consistent with our previous reports of distinct time constants which characterize the tardive thermal power regimeootnotetextSwartz. M., G. Verner, ``Dual Ohmic Controls Improve Understanding of `Heat after Death' '', Transactions American Nuclear Society, vol. 93, ISSN:0003-018X, 891-892 (2005) (`heat after death'), which results after all input electrical power is terminated to an active LANR device.

  12. Lattice sites of Na dopants in ZnO

    NASA Astrophysics Data System (ADS)

    Wahl, U.; Correia, J. G.; Amorim, L.; Decoster, S.; da Silva, M. R.; Pereira, L. M. C.

    2016-09-01

    The angular distribution of β ‑ particles emitted by the radioactive isotope 24Na was monitored following implantation into ZnO single crystals at fluences above 5 × 1012 cm‑2 at CERN’s ISOLDE facility. We identified sodium on two distinct sites: on substitutional Zn sites and on interstitial sites that are close to the so-called octahedral site. The interstitial Na was to a large extent already converted to substitutional Na for annealing at 200 °C, from which an activation energy of 0.8–1.3 eV, most likely around 1.2 eV, is estimated for the migration of interstitial Na in ZnO.

  13. Cooling and long-lived single-site localization of an ion in an optical lattice

    NASA Astrophysics Data System (ADS)

    Bylinskii, Alexei; Karpa, Leon; Gangloff, Dorian; Cetina, Marko; Vuletic, Vladan

    2013-05-01

    We report on localization of a continuously cooled single ion by a one-dimensional optical lattice. The ion is confined in a hybrid trap formed by an optical dipole potential produced by the standing-wave field of an optical cavity and a two-dimensional radio-frequency Paul trap transverse to the cavity axis. A lattice-assisted resolved Raman sideband process cools the ion to energies 20 times lower than the depth of the lattice potential, close to the vibrational ground state. We observe ion localization by measuring its displacement in the presence of a periodically driven electric field parallel to the lattice. We demonstrate full suppression of the driven ion motion due to optical localization to a single lattice site on a time-scale of 100 μs, which is 100 times longer than the vibrational period of the ion in the lattice site. At a longer time scale of 1 ms, driven motion is suppressed to 50%. The presented system paves the way to the realization of novel experiments studying classical and quantum friction models, and many-body physics with long-range interactions in periodic potentials. Army Research Office, National Science Foundation, National Science and Engineering Research Council of Canada, Alexander von Humboldt Foundation.

  14. Channelling experiments on the lattice location of hydrogen in metals using the nuclear reaction 1H(11B, α)αα

    NASA Astrophysics Data System (ADS)

    Yagi, Eiichi

    1992-03-01

    In order to locate hydrogen dissolved in metals a nuclear reaction 1H(11B, α)αα was applied to a channelling method. As an example of this application the results of the following two experiments were briefly reported. (1) The lattice location of H in V was investigated under a <001> compressive stress of 7 kg/mm2 below the elastic limit. The configuration of hydrogen is extremely sensitive to compressive stress and changes from a tetrahedral (T) site to a diplaced-T or 4T configuration. On release of this stress the hydrogen atoms returned to T-sites. (2) To elucidate the mechanism of the enhancement of the terminal solubility for hydrogen (TSH) in Nb on alloying with undersized Mo atoms, the state of hydrogen was studied in Nb-based Nb-Mo dilute alloys. It was demonstrated that H atoms are trapped by Mo atoms and located at sites displaced from T-sites by about 0.6 Å. This result supports the trapping model for the enhancement of the TSH in the region of low Mo concentration.

  15. Coincident site lattice-matched growth of semiconductors on substrates using compliant buffer layers

    DOEpatents

    Norman, Andrew

    2016-08-23

    A method of producing semiconductor materials and devices that incorporate the semiconductor materials are provided. In particular, a method is provided of producing a semiconductor material, such as a III-V semiconductor, on a silicon substrate using a compliant buffer layer, and devices such as photovoltaic cells that incorporate the semiconductor materials. The compliant buffer material and semiconductor materials may be deposited using coincident site lattice-matching epitaxy, resulting in a close degree of lattice matching between the substrate material and deposited material for a wide variety of material compositions. The coincident site lattice matching epitaxial process, as well as the use of a ductile buffer material, reduce the internal stresses and associated crystal defects within the deposited semiconductor materials fabricated using the disclosed method. As a result, the semiconductor devices provided herein possess enhanced performance characteristics due to a relatively low density of crystal defects.

  16. 43 CFR 3832.10 - Procedures for locating mining claims or sites.

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false Procedures for locating mining claims or...) BUREAU OF LAND MANAGEMENT, DEPARTMENT OF THE INTERIOR MINERALS MANAGEMENT (3000) LOCATING MINING CLAIMS OR SITES Locating Mining Claims or Sites § 3832.10 Procedures for locating mining claims or sites....

  17. Muscarinic acetylcholine receptors: location of the ligand binding site

    SciTech Connect

    Hulme, E.; Wheatley, M.; Curtis, C.; Birdsall, N.

    1987-05-01

    The key to understanding the pharmacological specificity of muscarinic acetylcholine receptors (mAChR's) is the location within the receptor sequence of the amino acid residues responsible for ligand binding. To approach this problem, they have purified mAChR's from rat brain to homogeneity by sequential ion-exchange chromatography, affinity chromatography and molecular weight fractionation. Following labelling of the binding site with an alkylating affinity label, /sup 3/H-propylbenzilycholine mustard aziridinium ion (/sup 3/H-PrBCM), the mAChR was digested with a lysine-specific endoproteinase, and a ladder of peptides of increasing molecular weight, each containing the glycosylated N-terminus, isolated by chromatography on wheat-germ agglutinin sepharose. The pattern of labelling showed that a residue in the peptides containing transmembrane helices 2 and/or 3 of the mAChR was alkylated. The linkage was cleaved by 1 M hydroxylamine, showing that /sup 3/H-PrBCM was attached to an acidic residue, whose properties strongly suggested it to be embedded in a hydrophobic intramembrane region of the mAChR. Examination of the cloned sequence of the mAChR reveals several candidate residues, the most likely of which is homologous to an aspartic acid residue thought to protonate the retinal Schiff's base in the congeneric protein rhodopsin.

  18. GIS modeling of archaeological site locations: A low-tech approach

    NASA Technical Reports Server (NTRS)

    Futato, Eugene M.

    1991-01-01

    A Geographic Information System (GIS)-type analysis of archaeological site locations using a dBase III plus program and a desk top computer is presented. A previously developed model of site locations in the Sequatchie Valley of northeastern Alabama is tested against known site locations in another large survey area there. The model fails to account for site locations in the test area. A model is developed for the test area and indicates the site locations are indeed different. Whether this is due to differences in site locations on a sub-regional level, or to sample error in the original model is unknown.

  19. Apodized structures for the integration of defect sites into photonic lattices

    SciTech Connect

    Boguslawski, Martin Kelberer, Andreas; Rose, Patrick; Denz, Cornelia

    2014-09-15

    We introduce a versatile concept to optically induce photonic structures of local refractive index modulations as well as photonic lattices holding single defect sites. For a given structure, we develop a set of nondiffracting beams obtained by fractionalizing the corresponding spatial spectrum. By combining this set in a multiplexing procedure, we achieve an incoherent combination of all individual structures of the set resulting in a locally addressable refractive index manipulation. We exemplarily present experimental results for apodized, meaning locally confined index changes in a photorefractive crystal resembling a sixfold and a circular symmetric structure. By an additional multiplexing step, we furthermore create periodic photonic lattices featuring embedded defects.

  20. Exact results for the site-dilute antiferromagnetic Ising model on finite triangular lattices

    NASA Astrophysics Data System (ADS)

    Farach, H. A.; Creswick, R. J.; Poole, C. P., Jr.

    1988-04-01

    Exact analytical and numerical results for the site-diluted antiferromagnetic Ising model on the triangular lattice (AFIT) are presented. For infinitesimal dilution the change in the free energy of the system is related to the distribution of local fields, and it is shown that for a frustrated system such as the AFIT, dilution lowers the entropy per spin. For lattices of finite size and dilution the transfer matrix for the partition function is evaluated numerically. The entropy per spin shows a marked minimum near a concentration of spins x=0.70, in some disagreement with earlier transfer-matrix results.

  1. Probing photon correlations in the dark sites of geometrically frustrated cavity lattices

    NASA Astrophysics Data System (ADS)

    Casteels, W.; Rota, R.; Storme, F.; Ciuti, C.

    2016-04-01

    We explore theoretically the driven-dissipative physics of geometrically frustrated lattices of cavity resonators with relatively weak nonlinearities, i.e., a photon-photon interaction smaller than the loss rate. In such systems, photon modes with zero probability at dark sites are present at the single-particle level due to interference effects. In particular, we study the behavior of a cell with three coupled resonators as well as extended Lieb lattices in one and two dimensions. By considering a partial pumping scheme, with the driving field not applied to the dark sites, we predict that even in the presence of relatively weak photon-photon interactions the nominally dark sites achieve a finite photonic population with strong correlations. We show that this is a consequence of biphoton and multiphoton states that in the absence of frustration would not be visible in the observables.

  2. 43 CFR 3832.1 - What does it mean to locate mining claims or sites?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... 43 Public Lands: Interior 2 2014-10-01 2014-10-01 false What does it mean to locate mining claims or sites? 3832.1 Section 3832.1 Public Lands: Interior Regulations Relating to Public Lands... CLAIMS OR SITES Locating Mining Claims or Sites § 3832.1 What does it mean to locate mining claims...

  3. 43 CFR 3832.1 - What does it mean to locate mining claims or sites?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 43 Public Lands: Interior 2 2011-10-01 2011-10-01 false What does it mean to locate mining claims or sites? 3832.1 Section 3832.1 Public Lands: Interior Regulations Relating to Public Lands... CLAIMS OR SITES Locating Mining Claims or Sites § 3832.1 What does it mean to locate mining claims...

  4. 43 CFR 3832.1 - What does it mean to locate mining claims or sites?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... 43 Public Lands: Interior 2 2012-10-01 2012-10-01 false What does it mean to locate mining claims or sites? 3832.1 Section 3832.1 Public Lands: Interior Regulations Relating to Public Lands... CLAIMS OR SITES Locating Mining Claims or Sites § 3832.1 What does it mean to locate mining claims...

  5. 43 CFR 3832.1 - What does it mean to locate mining claims or sites?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... 43 Public Lands: Interior 2 2013-10-01 2013-10-01 false What does it mean to locate mining claims or sites? 3832.1 Section 3832.1 Public Lands: Interior Regulations Relating to Public Lands... CLAIMS OR SITES Locating Mining Claims or Sites § 3832.1 What does it mean to locate mining claims...

  6. Reactive lattice oxygen sites for C sub 4 -hydrocarbon selective oxidation over. beta. -VOPO sub 4

    SciTech Connect

    Lashier, M.E.; Schrader, G.L. )

    1991-03-01

    The role of lattice oxygen species in the catalytic oxidation of n-butene to maleic anhydride has been investigated using {beta}-VOPO{sub 4} labeled with {sup 18}O. The catalyst was prepared by stoichiometric reaction of (VO){sub 2}P{sub 2}O{sub 7} with {sup 18}O{sub 2} using solid state preparation techniques. The {beta}-VOPO{sub 7/2} {sup 18}O{sub 1/2} was characterized using laser Raman and Fourier transform infrared spectroscopies: preferential incorporation at P-O-V sites was observed. A pulse reactor was used to react n-butane, 1-butene, 1,3-butadiene, furan, {gamma}-butyrolactone, and maleic anhydride with the catalyst in the absence of gas-phase O{sub 2}. Incorporation of {sup 18}O into the products was monitored by mass spectrometry. Specific lattice oxygen sites could be associated with the reaction pathways for selective or nonselective oxidation. The results of this study also indicate that the initial interaction of n-butane with {beta}-VOPO{sub 4} is fundamentally different from the initial interaction of olefins or oxygenated species. The approach used in this research-referred to as Isotopic Reactive-Site Mapping-is a potentially powerful method for probing the reactive lattice sites of other selective oxidation catalysts.

  7. Influence of crystal mosaicity on axial channeling effects and lattice site determination of impurities

    SciTech Connect

    De Vries, B.; Vantomme, A.; Wahl, U.; Ruffenach, S.; Briot, O.

    2013-10-21

    Using the electron emission channeling and Rutherford backscattering/channeling techniques, the influence of the mosaicity of a thin film on the axial channeling of charged particles was investigated. It is found that crystal mosaicity leads to a broadening and a degradation of the experimental channeling effects. This phenomenon, which is shown to be of major importance when assessing the lattice site of impurities in a single crystal, can be modeled quantitatively by using the mosaic tilt and twist components derived from X-ray rocking curve scans. As a case study, we illustrate that our approach allows to accurately determine the lattice site of Er in AlN, despite the significant influence of mosaicity on the channeling measurements.

  8. Effects of rapid quenching on the impurity site location in Zn-diffused InP

    SciTech Connect

    Yu, K.M.; Walukiewicz, W.; Chan, L.Y.; Leon, R.; Haller, E.E.; Jaklevic, J.M. ); Hanson, C.M. )

    1993-07-01

    The lattice locations of Zn atoms in heavily Zn-doped InP single crystal have been investigated by ion channeling techniques. The InP samples were rapidly quenched in diffusion pump oil after high-temperature Zn diffusion. Ion channeling experiments performed along various major crystal axes suggest that a large fraction (20%--30%) of the Zn atoms are in the tetrahedral interstitial position in the InP lattice. It has been found that although the maximum hole concentration is not significantly affected by the cooling rate, there is a substantial increase in the incorporation of Zn on substitutional and tetrahedral interstitial lattice locations in the rapidly cooled samples as compared to the slowly cooled samples. The consequences of these results for understanding the mechanisms leading to the saturation of the free-hole concentration in compound semiconductors are discussed.

  9. Nonlinear instabilities of multi-site breathers in Klein-Gordon lattices

    DOE PAGESBeta

    Cuevas-Maraver, Jesus; Kevrekidis, Panayotis G.; Pelinovsky, Dmitry E.

    2015-12-14

    Here, we explore the possibility of multi-site breather states in a nonlinear Klein–Gordon lattice to become nonlinearly unstable, even if they are found to be spectrally stable. The mechanism for this nonlinear instability is through the resonance with the wave continuum of a multiple of an internal mode eigenfrequency in the linearization of excited breather states. For the nonlinear instability, the internal mode must have its Krein signature opposite to that of the wave continuum. This mechanism is not only theoretically proposed, but also numerically corroborated through two concrete examples of the Klein–Gordon lattice with a soft (Morse) and amore » hard (Φ4) potential. Compared to the case of the nonlinear Schrödinger lattice, the Krein signature of the internal mode relative to that of the wave continuum may change depending on the period of the multi-site breather state. For the periods for which the Krein signatures of the internal mode and the wave continuum coincide, multi-site breather states are observed to be nonlinearly stable.« less

  10. Nonlinear instabilities of multi-site breathers in Klein-Gordon lattices

    SciTech Connect

    Cuevas-Maraver, Jesus; Kevrekidis, Panayotis G.; Pelinovsky, Dmitry E.

    2015-12-14

    Here, we explore the possibility of multi-site breather states in a nonlinear Klein–Gordon lattice to become nonlinearly unstable, even if they are found to be spectrally stable. The mechanism for this nonlinear instability is through the resonance with the wave continuum of a multiple of an internal mode eigenfrequency in the linearization of excited breather states. For the nonlinear instability, the internal mode must have its Krein signature opposite to that of the wave continuum. This mechanism is not only theoretically proposed, but also numerically corroborated through two concrete examples of the Klein–Gordon lattice with a soft (Morse) and a hard (Φ4) potential. Compared to the case of the nonlinear Schrödinger lattice, the Krein signature of the internal mode relative to that of the wave continuum may change depending on the period of the multi-site breather state. For the periods for which the Krein signatures of the internal mode and the wave continuum coincide, multi-site breather states are observed to be nonlinearly stable.

  11. A GIS typology to locate sites of submarine groundwater discharge.

    PubMed

    Rapaglia, John; Grant, Carley; Bokuniewicz, Henry; Pick, Tsvi; Scholten, Jan

    2015-07-01

    Although many researchers agree on the importance of submarine groundwater discharge (SGD), it remains difficult to locate and quantify this process. A groundwater typology was developed based on local digital elevation models and compared to concurrent radon mapping indicative of SGD in the Niantic River, CT USA. Areas of high radon activity were located near areas of high flow accumulation lending evidence to the utility of this approach to locate SGD. The benefits of this approach are three-fold: fresh terrestrial SGD may be quickly located through widely-available digital elevation models at little or no cost to the investigator; fresh SGD may also be quantified through the GIS approach by multiplying pixelated flow accumulation with the expected annual recharge; and, as these data necessarily quantify only fresh SGD, a comparison of these data with SGD as calculated by Rn activity may allow for the separation of the fresh and circulated fractions of SGD. This exercise was completed for the Niantic River where SGD as calculated by the GIS model is 1.2 m(3)/s, SGD as calculated by Rn activity is 0.73-5.5 m(3)/s, and SGD as calculated via a theoretical approach is 1.8-4.3 m(3)/s. Therefore fresh, terrestrial SGD accounts for 22-100% of total SGD in the Niantic River. PMID:25863321

  12. 14 CFR 420.25 - Launch site location review-risk analysis.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Launch site location review-risk analysis... Requirements for Obtaining a License § 420.25 Launch site location review—risk analysis. (a) If a flight... risk analysis. (b) For licensed launches, the FAA will not approve the location of the proposed...

  13. 14 CFR 420.25 - Launch site location review-risk analysis.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Launch site location review-risk analysis... Requirements for Obtaining a License § 420.25 Launch site location review—risk analysis. (a) If a flight... risk analysis. (b) For licensed launches, the FAA will not approve the location of the proposed...

  14. 14 CFR 420.25 - Launch site location review-risk analysis.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Launch site location review-risk analysis... Requirements for Obtaining a License § 420.25 Launch site location review—risk analysis. (a) If a flight... risk analysis. (b) For licensed launches, the FAA will not approve the location of the proposed...

  15. 14 CFR 420.25 - Launch site location review-risk analysis.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Launch site location review-risk analysis... Requirements for Obtaining a License § 420.25 Launch site location review—risk analysis. (a) If a flight... risk analysis. (b) For licensed launches, the FAA will not approve the location of the proposed...

  16. 14 CFR 420.25 - Launch site location review-risk analysis.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Launch site location review-risk analysis... Requirements for Obtaining a License § 420.25 Launch site location review—risk analysis. (a) If a flight... risk analysis. (b) For licensed launches, the FAA will not approve the location of the proposed...

  17. 25 CFR 214.28 - Location of sites for mines and buildings.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 25 Indians 1 2012-04-01 2011-04-01 true Location of sites for mines and buildings. 214.28 Section... OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.28 Location of sites for mines... location of wells, mines, buildings, plants, etc., the same shall be determined by the superintendent...

  18. 25 CFR 214.28 - Location of sites for mines and buildings.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 25 Indians 1 2011-04-01 2011-04-01 false Location of sites for mines and buildings. 214.28 Section... OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.28 Location of sites for mines... location of wells, mines, buildings, plants, etc., the same shall be determined by the superintendent...

  19. 25 CFR 214.28 - Location of sites for mines and buildings.

    Code of Federal Regulations, 2010 CFR

    2010-04-01

    ... 25 Indians 1 2010-04-01 2010-04-01 false Location of sites for mines and buildings. 214.28 Section... OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.28 Location of sites for mines... location of wells, mines, buildings, plants, etc., the same shall be determined by the superintendent...

  20. Featureless and nonfractionalized Mott insulators on the honeycomb lattice at 1/2 site filling

    PubMed Central

    Kimchi, Itamar; Parameswaran, S. A.; Turner, Ari M.; Wang, Fa; Vishwanath, Ashvin

    2013-01-01

    Within the Landau paradigm, phases of matter are distinguished by spontaneous symmetry breaking. Implicit here is the assumption that a completely symmetric state exists: a paramagnet. At zero temperature such quantum featureless insulators may be forbidden, triggering either conventional order or topological order with fractionalized excitations. Such is the case for interacting particles when the particle number per unit cell, f, is not an integer. However, can lattice symmetries forbid featureless insulators even at integer f? An especially relevant case is the honeycomb (graphene) lattice—where free spinless fermions at (the two sites per unit cell mean is half-filling per site) are always metallic. Here we present wave functions for bosons, and a related spin-singlet wave function for spinful electrons, on the honeycomb lattice and demonstrate via quantum to classical mappings that they do form featureless Mott insulators. The construction generalizes to symmorphic lattices at integer f in any dimension. Our results explicitly demonstrate that in this case, despite the absence of a noninteracting insulator at the same filling, lack of order at zero temperature does not imply fractionalization.

  1. Towards site-resolved imaging and control of ultracold fermions in optical lattices

    NASA Astrophysics Data System (ADS)

    Huber, Florian; Setiawan, Widagdo; Wooley-Brown, Kate; Parsons, Maxwell; Blatt, Sebastian; Greiner, Markus

    2012-06-01

    Recent successes in site-resolved imaging and control of bosonic Rb atoms trapped in optical lattices have enable many new possibilities to emulate simple condensed matter systems. Many of the open questions in condensed matter, however, stem from the fermionic nature of electrons. Extending the high degree of control available with ultracold quantum gases in optical lattices to fermionic atoms will allow us to address these questions. The light mass of fermionic 6-Li leads to system dynamics on fast timescales, making it an ideal candidate for such studies. We report progress towards a 6-Li quantum gas microscope and present improved imaging, cooling, and trapping techniques compatible with the light mass of 6-Li. A major challenge in the pursuit of single-site imaging with Lithium is cooling atoms during the imaging process. Single-site experiments with bosons benefit from the resolved hyperfine splitting in the excited state of 87-Rb, which allows the use of optical molasses. This method cannot be straightforwardly applied to 6-Li. We present our efforts to cool and image 6-Li using Raman sideband cooling.

  2. Site-resolved measurement of spin correlations for fermions in an optical lattice

    NASA Astrophysics Data System (ADS)

    Parsons, Maxwell; Mazurenko, Anton; Chiu, Christie; Ji, Geoffrey; Greif, Daniel; Greiner, Markus

    2016-05-01

    The recent demonstrations of site-resolved imaging of fermionic atoms in an optical lattice enable local measurements of charge correlations in Fermi lattice systems. Access to local spin correlations, however, has not yet been demonstrated. Measuring spin correlations is of particular interest because in the repulsive 2D Hubbard model, away from half-filling, the interplay of the spin and charge degrees of freedom is expected to give rise to pseudo-gap physics and perhaps d-wave superconductivity, but this doped regime is difficult to describe with current theoretical techniques. In this talk, I describe a new method for locally measuring spin correlations with our Fermi Gas Microscope. We observe nearest-neighbor AFM correlations in a two-component mixture of fermionic lithium atoms in a 2D optical lattice. The ability to measure trap-resolved magnetic correlations will allow us to explore entropy redistribution schemes, and may provide a way to access the low-temperature phases of the Hubbard model using ultracold atoms.

  3. Persistent random walk on a site-disordered one-dimensional lattice: Photon subdiffusion

    NASA Astrophysics Data System (ADS)

    Miri, Mirfaez; Sadjadi, Zeinab; Fouladvand, M. Ebrahim

    2006-03-01

    We study the persistent random walk of photons on a one-dimensional lattice of random transmittances. Transmittances at different sites are assumed independent, distributed according to a given probability density f(t) . Depending on the behavior of f(t) near t=0 , diffusive and subdiffusive transports are predicted by the disorder expansion of the mean square-displacement and the effective medium approximation. Monte Carlo simulations confirm the anomalous diffusion of photons. To observe photon subdiffusion experimentally, we suggest a dielectric film stack for realization of a distribution f(t) .

  4. 25 CFR 214.28 - Location of sites for mines and buildings.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 25 Indians 1 2014-04-01 2014-04-01 false Location of sites for mines and buildings. 214.28 Section 214.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.28 Location of sites for...

  5. 25 CFR 214.28 - Location of sites for mines and buildings.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 25 Indians 1 2013-04-01 2013-04-01 false Location of sites for mines and buildings. 214.28 Section 214.28 Indians BUREAU OF INDIAN AFFAIRS, DEPARTMENT OF THE INTERIOR ENERGY AND MINERALS LEASING OF OSAGE RESERVATION LANDS, OKLAHOMA, FOR MINING, EXCEPT OIL AND GAS § 214.28 Location of sites for...

  6. Feasibility study for locating archaeological village sites by satellite remote sensing techniques

    NASA Technical Reports Server (NTRS)

    Cook, J. P. (Principal Investigator)

    1972-01-01

    The author has identified the following significant results. As a result of ground truth activities, the accurate geographic location of an old fish camp was established as 64 deg 12 min 38 sec N, 158 deg 30 min 42 sec W. Previously the location of this very large abandoned village site was given only on a map sketched in 1935. This location and two other nearby sites will be used as ERTS training areas.

  7. Twinning in fcc lattice creates low-coordinated catalytically active sites in porous gold.

    PubMed

    Krajčí, Marian; Kameoka, Satoshi; Tsai, An-Pang

    2016-08-28

    We describe a new mechanism for creation of catalytically active sites in porous gold. Samples of porous gold prepared by de-alloying Al2Au exhibit a clear correlation between the catalytic reactivity towards CO oxidation and structural defects in the fcc lattice of Au. We have found that on the stepped {211} surfaces quite common twin boundary defects in the bulk structure of porous gold can form long close-packed rows of atoms with the coordination number CN = 6. DFT calculations confirm that on these low-coordinated Au sites dioxygen chemisorbs and CO oxidation can proceed via the Langmuir-Hinshelwood mechanism with the activation energy of 37 kJ/mol or via the CO-OO intermediate with the energy barrier of 19 kJ/mol. The existence of the twins in porous gold is stabilized by the surface energy. PMID:27586937

  8. Effect of forward looking sites on a multi-phase lattice hydrodynamic model

    NASA Astrophysics Data System (ADS)

    Redhu, Poonam; Gupta, Arvind Kumar

    2016-03-01

    A new multi-phase lattice hydrodynamic traffic flow model is proposed by considering the effect of multi-forward looking sites on a unidirectional highway. We examined the qualitative properties of proposed model through linear as well as nonlinear stability analysis. It is shown that the multi-anticipation effect can significantly enlarge the stability region on the phase diagram and exhibit three-phase traffic flow. It is also observed that the multi-forward looking sites have prominent influence on traffic flow when driver senses the relative flux of leading vehicles. Theoretical findings are verified using numerical simulation which confirms that the traffic jam is suppressed efficiently by considering the information of leading vehicles in unidirectional multi-phase traffic flow.

  9. Site location of Co in {beta}-FeSi{sub 2}

    SciTech Connect

    Dezsi, I.; Fetzer, Cs.; Kiss, M.; Degroote, S.; Vantomme, A.

    2005-10-01

    In order to reveal cationic site preference in {beta}-FeSi{sub 2}, Co-substituted samples synthesized by various techniques such as molecular beam epitaxy, ion implantation, and chemical vapor transport were investigated by {sup 57}Fe conversion electron Moessbauer (CEM) as well as {sup 57}Co Moessbauer emission (ME) spectroscopy. Literature on the structure of {beta}-FeSi{sub 2} is somewhat contradictory, especially on the point of the population of the two iron sites in the orthorhombic structure. {sup 57}Co ME and {sup 57}Fe CEM spectra both showed two quadrupole split spectral components in the crystalline phase. Hyperfine parameters indicate that Co atoms substitute Fe in both Fe positions in the orthorhombic lattice. The aim of the present study was to get reliable results on the relative population of the two iron sites and determine the substitution of the iron sites by Co atoms in the {beta}-FeSi{sub 2} lattice. The relative intensities of the two components in the absorption and emission Moessbauer spectra were found to be very similar for the samples prepared by different techniques, indicating a homogeneous distribution of Co on both Fe sites.

  10. Geometric frustration on a 1/9th site depleted triangular lattice

    NASA Astrophysics Data System (ADS)

    Hopkinson, John; Beck, Jarrett

    2013-03-01

    In the searches both for new spin liquid and spin ice (artificial and macroscopic) candidates, geometrically frustrated two-dimensional spin systems have played a prominent role. Here we present a study of the classical antiferromagnetic Ising (AFI) model on the sorrel net, a 1/9th site depleted and 1/7th bond depleted triangular lattice. The AFI model on this corner-shared triangle net is found to have a large residual entropy per spin S/N = 0 . 48185 +/- 0 . 00008 , indicating the sorrel net is highly geometrically frustrated. Anticipating that it may be difficult to achieve perfect bond depletion, we investigate the physics resulting from turning back on the depleted bonds (J2). We present the phase diagram, analytic expressions for the long range partially ordered ground state spin structure for antiferromagnetic J2 and the short range ordered ground state spin structure for ferromagnetic J2, the magnetic susceptibility and the static structure factor. We briefly comment on the possibility that artificial spin ice on the sorrel lattice could by made, and on a recent report [T. D. Keene et al., Dalton Trans. 40 2983 (2011)] of the creation of a 1/9th depleted cobalt hydroxide oxalate. This work was supported by NSERC (JMH) and NSERC USRA (JJB)

  11. 43 CFR 3832.11 - How do I locate mining claims or sites?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... follow both state and Federal law. (b) Your lode or placer claim is not valid until you make a discovery... land on which you are locating the claim or site is Federal land that is open to mineral entry...

  12. 43 CFR 3832.11 - How do I locate mining claims or sites?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... follow both state and Federal law. (b) Your lode or placer claim is not valid until you make a discovery... land on which you are locating the claim or site is Federal land that is open to mineral entry...

  13. 43 CFR 3832.11 - How do I locate mining claims or sites?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... follow both state and Federal law. (b) Your lode or placer claim is not valid until you make a discovery... land on which you are locating the claim or site is Federal land that is open to mineral entry...

  14. 43 CFR 3832.11 - How do I locate mining claims or sites?

    Code of Federal Regulations, 2014 CFR

    2014-10-01

    ... follow both state and Federal law. (b) Your lode or placer claim is not valid until you make a discovery... land on which you are locating the claim or site is Federal land that is open to mineral entry...

  15. Coincident site lattice bi-crystals growth-Impurity segregation towards grain boundaries

    NASA Astrophysics Data System (ADS)

    Autruffe, Antoine; Vines, Lasse; Arnberg, Lars; Di Sabatino, Marisa

    2015-04-01

    Bi-crystal silicon ingots with coincident site lattice (CSL) grain boundaries (GB), namely Σ3, Σ9, Σ27a, have been grown in a small scale Bridgman type furnace at 3 μm/s. Melts have been intentionally polluted with 25 ppma of copper and indium. Segregation of these impurities towards the central grain boundaries has been assessed by secondary ion mass spectrometry (SIMS). Influence of topological imperfections and grain boundary nature has been investigated. While copper segregation towards Σ3 GB has not been detected, copper has been found to diffuse towards Σ9 and Σ27a GB, especially at steps and GB junctions. Indium segregation has not been detected at any GB. This indicates that slow-diffusing element segregation towards GB depends on the boundary nature, and/or the grains orientation.

  16. Dislocation generation at near-coincidence site lattice grain boundaries during silicon directional solidification

    NASA Astrophysics Data System (ADS)

    Autruffe, Antoine; Stenhjem Hagen, Vegard; Arnberg, Lars; Di Sabatino, Marisa

    2015-02-01

    Bi-crystal silicon ingots separated by near-coincident site lattice (near-CSL) grain boundaries (GBs), namely Σ9 and Σ27a, have been grown in a small scale Bridgman-type furnace at 3 μm/s. Surface observations show different microstructure developments, depending on the nature of the seed GB and initial deviation from the low energy configuration. Grain boundary structure evolution and dislocation emission sources have been assessed for both types of GBs. Topological imperfections forming at the near - Σ9 and Σ27 GBs during the growth have been found to be the major source of defect generation. These imperfections are the result of the re-arrangement of the GBs during the growth due to the seed GBs deviation from low energy configurations - i.e. Σ9{221}1/{221}2 and Σ27a{511}1/{511}2.

  17. Bak–Tang–Wiesenfeld model on the square site-percolation lattice

    NASA Astrophysics Data System (ADS)

    Najafi, M. N.

    2016-08-01

    The Bak–Tang–Wiesenfeld (BTW) model is considered on the site-diluted square lattice, tuned by the occupancy probability p. Various statistical observables of the avalanches are analyzed in terms of p, e.g. the fractal dimension of their exterior frontiers, gyration radius, loop lengths and Green’s function. The model exhibits critical behavior for all amounts of p, and the exponents of the statistical observables are analyzed. We find a distinct universality class at p={p}c, which is unstable towards a p = 1 (BTW) fixed point. This universality class displays some common features such as a two-dimensional (2D) Ising universality class, e.g. the fractal dimension of loops in the thermodynamic limit is {D}Fp={pc}=1.38\\mp 0.01 which is compatible with the fractal dimension of geometrical spin clusters of the 2D critical Ising model (with {D}F{{Ising}}=\\tfrac{11}{8}).

  18. How Inhomogeneous Site Percolation Works on Bethe Lattices: Theory and Application

    NASA Astrophysics Data System (ADS)

    Ren, Jingli; Zhang, Liying; Siegmund, Stefan

    2016-03-01

    Inhomogeneous percolation, for its closer relationship with real-life, can be more useful and reasonable than homogeneous percolation to illustrate the critical phenomena and dynamical behaviour of complex networks. However, due to its intricacy, the theoretical framework of inhomogeneous percolation is far from being complete and many challenging problems are still open. In this paper, we first investigate inhomogeneous site percolation on Bethe Lattices with two occupation probabilities, and then extend the result to percolation with m occupation probabilities. The critical behaviour of this inhomogeneous percolation is shown clearly by formulating the percolation probability with given occupation probability p, the critical occupation probability , and the average cluster size where p is subject to . Moreover, using the above theory, we discuss in detail the diffusion behaviour of an infectious disease (SARS) and present specific disease-control strategies in consideration of groups with different infection probabilities.

  19. How Inhomogeneous Site Percolation Works on Bethe Lattices: Theory and Application

    PubMed Central

    Ren, Jingli; Zhang, Liying; Siegmund, Stefan

    2016-01-01

    Inhomogeneous percolation, for its closer relationship with real-life, can be more useful and reasonable than homogeneous percolation to illustrate the critical phenomena and dynamical behaviour of complex networks. However, due to its intricacy, the theoretical framework of inhomogeneous percolation is far from being complete and many challenging problems are still open. In this paper, we first investigate inhomogeneous site percolation on Bethe Lattices with two occupation probabilities, and then extend the result to percolation with m occupation probabilities. The critical behaviour of this inhomogeneous percolation is shown clearly by formulating the percolation probability with given occupation probability p, the critical occupation probability , and the average cluster size where p is subject to . Moreover, using the above theory, we discuss in detail the diffusion behaviour of an infectious disease (SARS) and present specific disease-control strategies in consideration of groups with different infection probabilities. PMID:26926785

  20. Investigation on the Ancient Site Location in the Mesopotamian Region Based on ALOS Data

    NASA Astrophysics Data System (ADS)

    Matsumoto, Ken; Hasegawa, Hitoshi; Ushiki, Hisao; Goto, Tomoya

    2008-11-01

    This project aims to investigate the location of ancient Mesopotamian sites in Iraq and to create a distribution map using ALOS data. Iraq is a centre of the ancient Mesopotamian civilization. A distribution map is essential to conduct a prompt investigation and preservation of ancient sites and cultural heritage in Iraq which are at risk of looting and robbery due to the recent Iraqi condition. Firstly this project enables to create Satellite Image Map of Iraq, where the acquisition of detailed map is not possible, based on ALOS Data. The ancient site of Mesopotamia is called "Tell" which is swelled up from the alluvial plain and forms like a hill with the bare land on the surface. Secondly, the estimation of locating ancient site has been undertaken by using the Satellite Image Interpretation method. Finally the locations of the ancient sites and the Satellite Image map are layered to produce the Distribution Map.

  1. Solution of a model of self-avoiding walks with multiple monomers per site on the Husimi lattice.

    PubMed

    Oliveira, Tiago J; Stilck, Jürgen F; Serra, Pablo

    2008-04-01

    We solve a model of self-avoiding walks which allows for a site to be visited up to two times by the walk on the Husimi lattice. This model is inspired in the Domb-Joyce model and was proposed to describe the collapse transition of polymers with one-site interactions only. We consider the version in which immediate self-reversals of the walk are forbidden. The phase diagram we obtain for the grand-canonical version of the model is similar to the one found in the solution of the Bethe lattice, with two distinct polymerized phases: a tricritical point and a critical endpoint. PMID:18517574

  2. Single Location - Tables of ALL SSE parameters for a single site

    Atmospheric Science Data Center

    2016-02-19

    ... web site home page, select " SSE ".  Select “Single Location.”  Select “Order Data.”  Enter the Latitude and Latitude of you location in DECIMAL Values and select “Submit”.  Choose the parameters ...

  3. Vertical view of Apollo 16 landing site located Descartes area lunar nearside

    NASA Technical Reports Server (NTRS)

    1971-01-01

    A vertical view of the Apollo 16 landing site located in the Descartes area lunar nearside. The overlay indicates the location of the proposed touchdown point for the Apollo 16 Lunar Module. Descartes is located west of the Sea of Nectar and southwest of the Sea of Tranquility. This photograph was taken with a 500mm lens camera from lunar orbit by the Apollo 14 crew.

  4. Validation of Innovative Exploration Technologies for Newberry Volcano: Drill Site Location Map 2010

    DOE Data Explorer

    Jaffe, Todd

    2012-01-01

    Newberry seeks to explore "blind" (no surface evidence) convective hydrothermal systems associated with a young silicic pluton on the flanks of Newberry Volcano. This project will employ a combination of innovative and conventional techniques to identify the location of subsurface geothermal fluids associated with the hot pluton. Newberry project drill site location map 2010. Once the exploration mythology is validated, it can be applied throughout the Cascade Range and elsewhere to locate and develop “blind” geothermal resources.

  5. Nuclear event time histories and computed site transfer functions for locations in the Los Angeles region

    USGS Publications Warehouse

    Rogers, A.M.; Covington, P.A.; Park, R.B.; Borcherdt, R.D.; Perkins, D.M.

    1980-01-01

    This report presents a collection of Nevada Test Site (NTS) nuclear explosion recordings obtained at sites in the greater Los Angeles, Calif., region. The report includes ground velocity time histories, as well as, derived site transfer functions. These data have been collected as part of a study to evaluate the validity of using low-level ground motions to predict the frequency-dependent response of a site during an earthquake. For this study 19 nuclear events were recorded at 98 separate locations. Some of these sites have recorded more than one of the nuclear explosions, and, consequently, there are a total of 159, three-component station records. The location of all the recording sites are shown in figures 1–5, the station coordinates and abbreviations are given in table 1. The station addresses are listed in table 2, and the nuclear explosions that were recorded are listed in table 3. The recording sites were chosen on the basis of three criteria: (1) that the underlying geological conditions were representative of conditions over significant areas of the region, (2) that the site was the location of a strong-motion recording of the 1971 San Fernando earthquake, or (3) that more complete geographical coverage was required in that location.

  6. 15 CFR 970.405 - Appropriate exploration site size and location.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.405 Appropriate exploration site size and location. Before the Administrator... 15 Commerce and Foreign Trade 3 2011-01-01 2011-01-01 false Appropriate exploration site size...

  7. 15 CFR 970.405 - Appropriate exploration site size and location.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... REGULATIONS OF THE ENVIRONMENTAL DATA SERVICE DEEP SEABED MINING REGULATIONS FOR EXPLORATION LICENSES Certification of Applications § 970.405 Appropriate exploration site size and location. Before the Administrator... 15 Commerce and Foreign Trade 3 2010-01-01 2010-01-01 false Appropriate exploration site size...

  8. 14 CFR 420.29 - Launch site location review for unproven launch vehicles.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Launch site location review for unproven launch vehicles. 420.29 Section 420.29 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Criteria and Information Requirements for Obtaining...

  9. 14 CFR 420.23 - Launch site location review-flight corridor.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Launch site location review-flight corridor. 420.23 Section 420.23 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Criteria and Information Requirements for Obtaining a License...

  10. 14 CFR 420.29 - Launch site location review for unproven launch vehicles.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... launch vehicles. An applicant for a license to operate a launch site for an unproven launch vehicle shall... 14 Aeronautics and Space 4 2011-01-01 2011-01-01 false Launch site location review for unproven launch vehicles. 420.29 Section 420.29 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION,...

  11. 14 CFR 420.29 - Launch site location review for unproven launch vehicles.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... launch vehicles. An applicant for a license to operate a launch site for an unproven launch vehicle shall... 14 Aeronautics and Space 4 2012-01-01 2012-01-01 false Launch site location review for unproven launch vehicles. 420.29 Section 420.29 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION,...

  12. 14 CFR 420.29 - Launch site location review for unproven launch vehicles.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... launch vehicles. An applicant for a license to operate a launch site for an unproven launch vehicle shall... 14 Aeronautics and Space 4 2014-01-01 2014-01-01 false Launch site location review for unproven launch vehicles. 420.29 Section 420.29 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION,...

  13. 14 CFR 420.29 - Launch site location review for unproven launch vehicles.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... launch vehicles. An applicant for a license to operate a launch site for an unproven launch vehicle shall... 14 Aeronautics and Space 4 2010-01-01 2010-01-01 false Launch site location review for unproven launch vehicles. 420.29 Section 420.29 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION,...

  14. 14 CFR 420.27 - Launch site location review-information requirements.

    Code of Federal Regulations, 2013 CFR

    2013-01-01

    ... 14 Aeronautics and Space 4 2013-01-01 2013-01-01 false Launch site location review-information requirements. 420.27 Section 420.27 Aeronautics and Space COMMERCIAL SPACE TRANSPORTATION, FEDERAL AVIATION ADMINISTRATION, DEPARTMENT OF TRANSPORTATION LICENSING LICENSE TO OPERATE A LAUNCH SITE Criteria and Information Requirements for Obtaining...

  15. Quantum phase transition of a Bose gas in a lattice with a controlled number of atoms per site

    NASA Astrophysics Data System (ADS)

    Du, Xu

    2005-05-01

    We have studied the superfluid-Mott insulator quantum phase transition [1] of a gas of ^87Rb atoms in an optical lattice. We are able to prepare the gas with a controllable number of one, two, or three atoms per lattice site, as verified with photoassociation spectroscopy. We measure momentum distributions using standard time-of-flight imaging techniques. These are similar to those of ref. [1], and exhibit narrow peaks at moderate lattice strengths. We find that the width of these peaks increases for lattice heights greater than about 13 times the recoil energy [2], and we observe interesting differences in this behavior, depending on the number of atoms per site. The data suggest that the quantum phase transition occurs at higher lattice strength with larger site occupation. We acknowledge the support of this work by the R. A. Welch Foundation, The N. S. F., and the D.O.E. Quantum Optics Initiative. [1] Markus Greiner et al., Nature 415, 39 (2002). [2] Thilo St"oferle et al., Phys. Rev. Lett. 92, 130403 (2004).

  16. Stratigraphic Profiles for Selected Hanford Site Seismometer Stations and Other Locations

    SciTech Connect

    Last, George V.

    2014-02-01

    Stratigraphic profiles were constructed for eight selected Hanford Site seismometer stations, five Hanford Site facility reference locations, and seven regional three-component broadband seismometer stations. These profiles provide interpretations of the subsurface layers to support estimation of ground motions from past earthquakes, and the prediction of ground motions from future earthquakes. In most cases these profiles terminated at the top of the Wanapum Basalt, but at selected sites profiles were extended down to the top of the crystalline basement. The composite one-dimensional stratigraphic profiles were based primarily on previous interpretations from nearby boreholes, and in many cases the nearest deep borehole is located kilometers away.

  17. Lattice Location of 12B in Single-Crystal Ni3Al Studied by -Radiation Detected NMR

    NASA Astrophysics Data System (ADS)

    Fischer, B.; Ittermann, B.; Diehl, E.; Dippel, R.; Ergezinger, K. H.; Frank, H.-P.; Jäger, E.; Seelinger, W.; Sulzer, G.; Ackermann, H.; Stöckmann, H.-J.; Bohn, H. G.

    -radiation detected nuclear magnetic resonance was applied to determine the location of 12B probe nuclei in a Ni3Al single crystal. Combining our results with those of channeling experiments it turned out that more than 90% of the 12B ions occupy the octahedral interstitial site with six Ni ions as nearest neighbours.Translated AbstractGitterplatzbestimmung von 12B im Ni3Al-Einkristall mittels -strahlungsdetektierter NMRDer Einbauplatz des Sondenkerns 12B im Ni3Al-Einkristall wurde durch Kernresonanz mit β-Strahlungsnachweis bestimmt. Aus der Kombination mit Ergebnissen von Gitterführungsexperimenten ergab sich, daß über 90% der 12B-Ionen auf oktaedrischen Zwischengitterplätzen mit sechs Ni-Ionen als nächsten Nachbarn eingebaut werden.

  18. Lattice sites, charge states and spin-lattice relaxation of Fe ions in 57Mn+ implanted GaN and AlN

    NASA Astrophysics Data System (ADS)

    Masenda, H.; Naidoo, D.; Bharuth-Ram, K.; Gunnlaugsson, H. P.; Johnston, K.; Mantovan, R.; Mølholt, T. E.; Ncube, M.; Shayestehaminzadeh, S.; Gíslason, H. P.; Langouche, G.; Ólafsson, S.; Weyer, G.

    2016-03-01

    The lattice sites, valence states, resulting magnetic behaviour and spin-lattice relaxation of Fe ions in GaN and AlN were investigated by emission Mössbauer spectroscopy following the implantation of radioactive 57Mn+ ions at ISOLDE/CERN. Angle dependent measurements performed at room temperature on the 14.4 keV γ-rays from the 57Fe Mössbauer state (populated from the 57Mn β- decay) reveal that the majority of the Fe ions are in the 2+ valence state nearly substituting the Ga and Al cations, and/or associated with vacancy type defects. Emission Mössbauer spectroscopy experiments conducted over a temperature range of 100-800 K show the presence of magnetically split sextets in the "wings" of the spectra for both materials. The temperature dependence of the sextets relates these spectral features to paramagnetic Fe3+ with rather slow spin-lattice relaxation rates which follow a T2 temperature dependence characteristic of a two-phonon Raman process.

  19. 14 CFR 420.21 - Launch site location review-launch site boundary.

    Code of Federal Regulations, 2014 CFR

    2014-01-01

    ... the debris dispersion radius of the largest launch vehicle type and weight class proposed for the launch point. (b) For a launch site supporting any expendable launch vehicle, an applicant shall use the largest distance provided by table 2 for the type and weight class of any launch vehicle proposed for...

  20. 14 CFR 420.21 - Launch site location review-launch site boundary.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... the debris dispersion radius of the largest launch vehicle type and weight class proposed for the launch point. (b) For a launch site supporting any expendable launch vehicle, an applicant shall use the largest distance provided by table 2 for the type and weight class of any launch vehicle proposed for...

  1. 14 CFR 420.21 - Launch site location review-launch site boundary.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... the debris dispersion radius of the largest launch vehicle type and weight class proposed for the launch point. (b) For a launch site supporting any expendable launch vehicle, an applicant shall use the largest distance provided by table 2 for the type and weight class of any launch vehicle proposed for...

  2. 14 CFR 420.21 - Launch site location review-launch site boundary.

    Code of Federal Regulations, 2012 CFR

    2012-01-01

    ... the debris dispersion radius of the largest launch vehicle type and weight class proposed for the launch point. (b) For a launch site supporting any expendable launch vehicle, an applicant shall use the largest distance provided by table 2 for the type and weight class of any launch vehicle proposed for...

  3. Male mate location behaviour and encounter sites in a community of tropical butterflies: taxonomic and site associations and distinctions.

    PubMed

    Tiple, Ashish D; Padwad, Sonali V; Dapporto, Leonardo; Dennis, Roger L H

    2010-12-01

    Male mate location behaviour and encounter sites have been studied in 72 butterfly species at Nagpur, India, and related to taxonomy, morphology, habitat and population parameters. Species can be placed in three broad classes of mate location behaviour: invariant patrolling, invariant perching, and perch-patrol, the latter associated with increasing site fidelity, territorial defence and male assemblages. Significant taxonomic differences occur, closely related species tending to share mate location behaviours. Morphological differences are found with heavier and larger butterflies displaying greater site fidelity and territorial defence, and differences occur between individuals of species which both perch and patrol. Invariant patrolling is particularly associated with tracks through vegetation, host planttrack distributions, and high female to male numbers observed on transects; invariant perching is linked more to edge features than patrolling, and to lower population counts on transects. Species which perch-patrol, defend territories and establish male assemblages are associated with more complex vegetation structures, and have encounter sites at vegetation edges, landforms and predictable resource (host plant) concentrations. Attention is drawn to the importance of distinctive mate encounter sites for the conservation of butterfly species' habitats. PMID:21289445

  4. Effects of Vegetation Structure on the Location of Lion Kill Sites in African Thicket.

    PubMed

    Davies, Andrew B; Tambling, Craig J; Kerley, Graham I H; Asner, Gregory P

    2016-01-01

    Predator-prey relationships are integral to ecosystem stability and functioning. These relationships are, however, difficult to maintain in protected areas where large predators are increasingly being reintroduced and confined. Where predators make kills has a profound influence on their role in ecosystems, but the relative importance of environmental variables in determining kill sites, and how these might vary across ecosystems is poorly known. We investigated kill sites for lions in South Africa's thicket biome, testing the importance of vegetation structure for kill site locations compared to other environmental variables. Kill sites were located over four years using GPS telemetry and compared to non-kill sites that had been occupied by lions, as well as to random sites within lion ranges. Measurements of 3D vegetation structure obtained from Light Detection and Ranging (LiDAR) were used to calculate the visible area (viewshed) around each site and, along with wind and moonlight data, used to compare kill sites between lion sexes, prey species and prey sexes. Viewshed area was the most important predictor of kill sites (sites in dense vegetation were twice as likely to be kill sites compared to open areas), followed by wind speed and, less so, moonlight. Kill sites for different prey species varied with vegetation structure, and male prey were killed when wind speeds were higher compared to female prey of the same species. Our results demonstrate that vegetation structure is an important component of predator-prey interactions, with varying effects across ecosystems. Such differences require consideration in terms of the ecological roles performed by predators, and in predator and prey conservation. PMID:26910832

  5. Effects of Vegetation Structure on the Location of Lion Kill Sites in African Thicket

    PubMed Central

    Davies, Andrew B.; Tambling, Craig J.; Kerley, Graham I. H.; Asner, Gregory P.

    2016-01-01

    Predator-prey relationships are integral to ecosystem stability and functioning. These relationships are, however, difficult to maintain in protected areas where large predators are increasingly being reintroduced and confined. Where predators make kills has a profound influence on their role in ecosystems, but the relative importance of environmental variables in determining kill sites, and how these might vary across ecosystems is poorly known. We investigated kill sites for lions in South Africa’s thicket biome, testing the importance of vegetation structure for kill site locations compared to other environmental variables. Kill sites were located over four years using GPS telemetry and compared to non-kill sites that had been occupied by lions, as well as to random sites within lion ranges. Measurements of 3D vegetation structure obtained from Light Detection and Ranging (LiDAR) were used to calculate the visible area (viewshed) around each site and, along with wind and moonlight data, used to compare kill sites between lion sexes, prey species and prey sexes. Viewshed area was the most important predictor of kill sites (sites in dense vegetation were twice as likely to be kill sites compared to open areas), followed by wind speed and, less so, moonlight. Kill sites for different prey species varied with vegetation structure, and male prey were killed when wind speeds were higher compared to female prey of the same species. Our results demonstrate that vegetation structure is an important component of predator-prey interactions, with varying effects across ecosystems. Such differences require consideration in terms of the ecological roles performed by predators, and in predator and prey conservation. PMID:26910832

  6. Foraging location and site fidelity of the Double-crested Cormorant on Oneida Lake, New York

    USGS Publications Warehouse

    Coleman, J.T.H.; Richmond, M.E.; Rudstam, L. G.; Mattison, P.M.

    2005-01-01

    We studied the foraging behavior of the Double-crested Cormorant (Phalacrocorax auritus) on Oneida Lake, New York, by monitoring the activities of 27 radio-tagged birds in July and August of 1999 and 2000. A total of 224 locations were obtained of cormorants actively diving, and presumed foraging, at the time of detection. A geographic information system was used to examine foraging distances from the nesting island, the water depth and type of substrate at preferred foraging sites, and to estimate kernel home ranges for analysis of individual foraging site fidelity. An explanatory model was developed to determine parameters affecting the distance to cormorant foraging sites. The mean distance to foraging locations of tagged cormorants from the colony site was 2,920 m (SE ?? 180 m, max = 14,190 m), and 52% of the locations were within 2,000 m of the nesting island. No cormorant was observed making daily foraging trips to outside water bodies. Mean foraging distance was greater during morning than in the afternoon, and there was a significant effect of the time of day on distance. There was no significant effect of sex date, a seasonal measure on distance to foraging location. Individual cormorants exhibited fidelity to specific foraging sites. Most cormorants foraged in close proximity to the nesting island much of the time, while those detected further from the island tended to return repeatedly to the same locations. Ninety percent of the foraging locations were in water depths ???7.5 m, and most were in water 2.5-5 m deep. Compositional analysis of habitat use revealed a preference for these depths, along with substrates of cobble with rubble, and silt with clay.

  7. Charge-patterning phase transition on a surface lattice of titratable sites adjacent to an electrolyte solution

    NASA Astrophysics Data System (ADS)

    Shore, Joel; Thurston, George

    We discuss a model for a charge-patterning phase transition on a two-dimensional square lattice of titratable sites, here regarded as protonation sites, placed on a square lattice in a dielectric medium just below the planar interface between this medium and an aqueous salt solution. Within Debye-Huckel theory, the analytical form of the electrostatic repulsion between protonated sites exhibits an approximate inverse cubic power-law decrease beyond short distances. The problem can thus be mapped onto the two-dimensional antiferromagnetic Ising model with this longer-range interaction, which we study with Monte Carlo simulations. As we increase pH, the occupation probability of a site decreases from 1 at low pH to 0 at high pH. For sufficiently-strong interaction strengths, a phase transition occurs as the occupation probability of 1/2 is approached: the charges arrange themselves into a checkerboard pattern. This ordered phase persists over a range of pH until a transition occurs back to a disordered state. This state is the analogue of the Neel state in the antiferromagnetic Ising spin model. More complicated ordered phases are expected for sufficiently strong interactions (with occupation probabilities of 1/4 and 3/4) and if the lattice is triangular rather than square. This work was supported by NIH EY018249 (GMT).

  8. Water Quality Sampling Locations Along the Shoreline of the Columbia River, Hanford Site, Washington

    SciTech Connect

    Peterson, Robert E.; Patton, Gregory W.

    2009-12-14

    As environmental monitoring evolved on the Hanford Site, several different conventions were used to name or describe location information for various sampling sites along the Hanford Reach of the Columbia River. These methods range from handwritten descriptions in field notebooks to the use of modern electronic surveying equipment, such as Global Positioning System receivers. These diverse methods resulted in inconsistent archiving of analytical results in various electronic databases and published reports because of multiple names being used for the same site and inaccurate position data. This document provides listings of sampling sites that are associated with groundwater and river water sampling. The report identifies names and locations for sites associated with sampling: (a) near-river groundwater using aquifer sampling tubes; (b) riverbank springs and springs areas; (c) pore water collected from riverbed sediment; and (d) Columbia River water. Included in the listings are historical names used for a particular site and the best available geographic coordinates for the site, as of 2009. In an effort to create more consistency in the descriptive names used for water quality sampling sites, a naming convention is proposed in this document. The convention assumes that a unique identifier is assigned to each site that is monitored and that this identifier serves electronic database management requirements. The descriptive name is assigned for the convenience of the subsequent data user. As the historical database is used more intensively, this document may be revised as a consequence of discovering potential errors and also because of a need to gain consensus on the proposed naming convention for some water quality monitoring sites.

  9. Site preference and lattice relaxation around 4d and 5d refractory elements in Ni3Al.

    PubMed

    Umićević, Ana; Mahnke, Heinz-Eberhard; Belošević-Čavor, Jelena; Cekić, Božidar; Schumacher, Gerhard; Madjarevic, Ivan; Koteski, Vasil

    2016-01-01

    X-ray absorption spectroscopy is employed to investigate site preference and lattice relaxation around Mo, Ru, Hf, W and Re dopants in Ni3Al. The site occupation preference and the measured distances between the refractory elements as dopants and the nearest host atoms are compared with the results of ab initio calculations within the density functional theory. Combined experimental and theoretical results indicate that Mo, Hf, W and Re atoms reside on the Al sublattice in Ni3Al, while Ru atoms occupy the Ni sublattice. A more pronounced lattice relaxation was detected in the case of Hf and Ru doping, with a strong outward relaxation of the nearest Ni and Al atoms. PMID:26698076

  10. New understanding of the role of coincidence site lattice boundaries in abnormal grain growth of aluminium alloy

    NASA Astrophysics Data System (ADS)

    Park, Chang-Soo; Park, Hyung-Ki; Shim, Hyung-Seok; Na, Tae-Wook; Han, Chan-Hee; Hwang, Nong-Moon

    2015-04-01

    The sequential microstructure evolution of abnormal grain growth (AGG) in the aluminium alloy (AA5052) was investigated to analyse the migration behaviour of coincidence site lattice (CSL) boundaries, which are known to play an important role in inducing AGG. The sequential evolution showed that CSL boundaries tend to disappear more slowly than general boundaries at the growth front of abnormally growing grains. Especially, the migration rate of Σ9 boundaries was noticeably low, which is contrary to the previous suggestions.

  11. Capacitated location of collection sites in an urban waste management system

    SciTech Connect

    Ghiani, Gianpaolo; Lagana, Demetrio; Manni, Emanuele; Triki, Chefi

    2012-07-15

    Urban waste management is becoming an increasingly complex task, absorbing a huge amount of resources, and having a major environmental impact. The design of a waste management system consists in various activities, and one of these is related to the location of waste collection sites. In this paper, we propose an integer programming model that helps decision makers in choosing the sites where to locate the unsorted waste collection bins in a residential town, as well as the capacities of the bins to be located at each collection site. This model helps in assessing tactical decisions through constraints that force each collection area to be capacitated enough to fit the expected waste to be directed to that area, while taking into account Quality of Service constraints from the citizens' point of view. Moreover, we propose an effective constructive heuristic approach whose aim is to provide a good solution quality in an extremely reduced computational time. Computational results on data related to the city of Nardo, in the south of Italy, show that both exact and heuristic approaches provide consistently better solutions than that currently implemented, resulting in a lower number of activated collection sites, and a lower number of bins to be used.

  12. Factors affecting the location and shape of face seal leak sites on half-mask respirators.

    PubMed

    Oestenstad, Riedar Kent; Bartolucci, Alfred A

    2010-06-01

    While there have been a number of studies on the effect of leak site and shape on the magnitude of measured leakage through respirator face seals, there have been very few studies to identify the location and size of these leaks. In a previous study we used a method of identifying the location and shape of respirator leaks on a half-mask respirator by the deposition of a fluorescent tracer during a fit test, and testing for their association with facial dimensions. The purpose of this study was to apply that methodology to conduct multiple fit tests to determine if gender, respirator brand, repeated fit tests, and test exercises affected the location and shape of face seal leak sites. Categorical analysis found that none of these factors had a significant effect on the location and shape of leaks. General linear model analysis found some significant effects of the study factors on leaks, but facial dimensions had a greater effect, and there were significant differences between facial dimensions of subjects with a leak and those without. Significant differences in leak site distributions between this and the previous study may have been due to differences in facial dimensions and racial/ethnic composition. Twice as many diffuse leaks as point leaks were observed in both studies, indicating that slit-like leaks would be most appropriate on mannequins used in laboratory respirator leakage studies, and in respirator flow and penetration models. That the study factors had no significant effects in the categorical analysis, significant effects for facial dimensions were found in the linear analysis, and leak site distribution differences between this and our previous study may have been affected by differences in facial dimensions, indicate that, in addition to size, the shape of an individual's face may be an important determinant of leak sites on a half-mask respirator. This would have implications for the design of respirator facepieces and in the selection of

  13. Feasibility study for locating archaeological village sites by satellite remote sensing techniques. [multispectral photography of Alaska

    NASA Technical Reports Server (NTRS)

    Cook, J. P. (Principal Investigator); Stringer, W. J.

    1974-01-01

    The author has identified the following significant results. The objective is to determine the feasibility of detecting large Alaskan archaeological sites by satellite remote sensing techniques and mapping such sites. The approach used is to develop digital multispectral signatures of dominant surface features including vegetation, exposed soils and rock, hydrological patterns and known archaeological sites. ERTS-1 scenes are then printed out digitally in a map-like array with a letter reflecting the most appropriate classification representing each pixel. Preliminary signatures were developed and tested. It was determined that there was a need to tighten up the archaeological site signature by developing accurate signatures for all naturally-occurring vegetation and surface conditions in the vicinity of the test area. These second generation signatures have been tested by means of computer printouts and classified tape displays on the University of Alaska CDU-200 and by comparison with aerial photography. It has been concluded that the archaeological signatures now in use are as good as can be developed. Plans are to print out signatures for the entire test area and locate on topographic maps the likely locations of archaeological sites within the test area.

  14. Feasibility study for locating archaeological village sites by satellite remote sensing techniques

    NASA Technical Reports Server (NTRS)

    Cook, J. P. (Principal Investigator)

    1973-01-01

    The author has identified the following significant results. Examination of NASA-provided aerial photography at the Pt. Hope, Alaska area has revealed numerous house pits, or the remains of former subterranean houses which have caved in. Although three major groupings of former house sites have previously been identified, a fourth area, north of the group known as Jabbertown had not previously been identified. It appears that this fourth site is quite extensive and may be of significance to understanding the sequence of habitation of the Pt. Hope location.

  15. Momentum, water vapor, and carbon dioxide exchange at a centrally located prairie site during FIFE

    NASA Technical Reports Server (NTRS)

    Verma, Shashi B.; Kim, Joon; Clement, Robert J.

    1992-01-01

    Eddy correlation measurements were taken of momentum, water vapor, sensible heat, and CO2 at a centrally located plateau site in the FIFE study area from May to October 1987. Approximately 82 percent of the vegetation at the site was composed of several C4 grass species, with the remainder being C3 grasses, forbs, wedges, and woody plants. Precipitation was about normal during the study period, except for a three week dry period in late July to early August that caused moisture stress conditions.

  16. 43 CFR 3838.10 - Procedures for locating and recording a mining claim or tunnel site on SRHA lands.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... mining claim or tunnel site on SRHA lands. 3838.10 Section 3838.10 Public Lands: Interior Regulations... MANAGEMENT (3000) SPECIAL PROCEDURES FOR LOCATING AND RECORDING MINING CLAIMS AND TUNNEL SITES ON STOCKRAISING HOMESTEAD ACT (SRHA) LANDS Locating and Recording Mining Claims and Tunnel Sites on SRHA...

  17. 43 CFR 3838.11 - How do I locate and record mining claims or tunnel sites on SRHA lands?

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... or tunnel sites on SRHA lands? 3838.11 Section 3838.11 Public Lands: Interior Regulations Relating to...) SPECIAL PROCEDURES FOR LOCATING AND RECORDING MINING CLAIMS AND TUNNEL SITES ON STOCKRAISING HOMESTEAD ACT (SRHA) LANDS Locating and Recording Mining Claims and Tunnel Sites on SRHA Lands § 3838.11 How do...

  18. Determining Optimal Location and Numbers of Sample Transects for Characterization of UXO Sites

    SciTech Connect

    BILISOLY, ROGER L.; MCKENNA, SEAN A.

    2003-01-01

    Previous work on sample design has been focused on constructing designs for samples taken at point locations. Significantly less work has been done on sample design for data collected along transects. A review of approaches to point and transect sampling design shows that transects can be considered as a sequential set of point samples. Any two sampling designs can be compared through using each one to predict the value of the quantity being measured on a fixed reference grid. The quality of a design is quantified in two ways: computing either the sum or the product of the eigenvalues of the variance matrix of the prediction error. An important aspect of this analysis is that the reduction of the mean prediction error variance (MPEV) can be calculated for any proposed sample design, including one with straight and/or meandering transects, prior to taking those samples. This reduction in variance can be used as a ''stopping rule'' to determine when enough transect sampling has been completed on the site. Two approaches for the optimization of the transect locations are presented. The first minimizes the sum of the eigenvalues of the predictive error, and the second minimizes the product of these eigenvalues. Simulated annealing is used to identify transect locations that meet either of these objectives. This algorithm is applied to a hypothetical site to determine the optimal locations of two iterations of meandering transects given a previously existing straight transect. The MPEV calculation is also used on both a hypothetical site and on data collected at the Isleta Pueblo to evaluate its potential as a stopping rule. Results show that three or four rounds of systematic sampling with straight parallel transects covering 30 percent or less of the site, can reduce the initial MPEV by as much as 90 percent. The amount of reduction in MPEV can be used as a stopping rule, but the relationship between MPEV and the results of excavation versus no

  19. Random site dilution properties of frustrated magnets on a hierarchical lattice.

    PubMed

    Fortin, Jean-Yves

    2013-07-24

    We present a method to analyze the magnetic properties of frustrated Ising spin models on specific hierarchical lattices with random dilution. Disorder is induced by dilution and geometrical frustration rather than randomness in the internal couplings of the original Hamiltonian. The two-dimensional model presented here possesses a macroscopic entropy at zero temperature in the large size limit, very close to the Pauling estimate for spin-ice on the pyrochlore lattice, and a crossover towards a paramagnetic phase. The disorder due to dilution is taken into account by considering a replicated version of the recursion equations between partition functions at different lattice sizes. An analysis to first order in replica number allows a systematic reorganization of the disorder configurations, leading to a recurrence scheme. This method is numerically implemented to evaluate thermodynamical quantities such as specific heat and susceptibility in an external field. PMID:23807800

  20. An expert approach to archaeological sites location through remote sensing information

    NASA Astrophysics Data System (ADS)

    Carla, Roberto; Jacoli, Maria; Profeti, Giuliana; Venturi, Valerio

    2003-03-01

    It is commonly accepted that the spatial distribution of archaeological sites is largely dependent on the characteristics of the environment. Hence, during the last decades, many studies have been focused on selecting environmental characteristics that can be used successfully in predicting unknown site locations. In previous studies the authors, using experimental tests and ground surveys, analysed many environmental factors and identified the most important ones for defining the inclination of an area to settling. Some of these could be obtained from cartography and Digital Elevation Models (DEM), whereas others were extracted from remote sensing imagery. In this work, Landsat ETM and IKONOS-2 satellite data were used to obtain environmental information useful in predicting new archaeological sites using an expert euristic approach. The information obtained from satellite data, plus a few other environmental descriptors, was used to build a predictive archaeological model that characterised an inclination to settle in the test area (region of Lucania in Southern Italy). The map of settlement tendency thus obtained, which was verified during few ground surveys, led to the identification of more than one hundred new archaeological sites, with a prediction accuracy greater than 80%. The environmental characteristics of the new archaeological locations were then statistically analysed and their effectiveness was evaluated. The results demonstrated that the integration of remotely-sensed information within an archaeological model greatly enhanced the capabilities for searching out identifying new archaeological settlements.

  1. Migration and Residential Location of Workers at Nuclear Power Plant Construction Sites Forecasting Methodology

    SciTech Connect

    Malhotra, S.; Manninen, D.

    1981-04-01

    The primary objective of this study was to improve the accuracy of socioeconomic impact assessments by providing an improved methodology for predicting the number of inmigrating workers and their residential location patterns at future nuclear power plant construction projects. Procedures for estimating several other variables which have important implications with respect to socioeconomic impact assessment (i.e., relocation of dependents, intention to remain in the area, type of housing selected, marital status, and average family size) were also developed. The analysis was based on worker survey data from 28 surveys which were conducted at 13 nuclear power plant construction sites. These survey data were examined to identify patterns of variation in variables of interest across sites as well as across various worker groups. In addition, considerable secondary data reflecting various regional and project characteristics were gathered for each site. These data were used to estimate the effects of factors underlying the observed variation in craft-specific migrant proportions and the residential location patterns of inmigrating workers across sites and surveys. The results of these analyses were then used as a basis for the specification of the forecasting procedures.

  2. A stochastic method for optimal location of groundwater monitoring sites at aquifer scale

    NASA Astrophysics Data System (ADS)

    Barca, E.; Passarella, G.

    2009-04-01

    With the growth of public environmental awareness and the improvement in national and EU legislation regarding the environment, monitoring assumed great importance in the frame of all managerial activities related to territories. In particular, recently, a number of public environmental agencies have invested great resources in planning and operating improvements on existing monitoring networks within their regions. In this framework, and, at the light of the Water Framework Directive, the optimal monitoring of the qualitative and quantitative state of groundwater becomes a priority, particularly, when severe economic constraints must be imposed and the territory to be monitored is quite wide. There are a lot of reasons justifying the optimal extension of a monitoring network. In fact, a modest coverage of the monitored area often makes impossible to provide the manager with a sufficient knowledge for decision-making processes. In general, monitoring networks are characterized by a scarce number of existing wells, irregularly spread over the considered area. This is a typical case of optimization and it may be solved seeking among existing, but unused, wells, all and only those able to make the monitoring network coverage, the most uniform among any arrangement. Using existing wells as new monitoring sites, allows one to drastically reduce the needed budget. In this paper, a four step method, based on simulated annealing, has been implemented with the aim of identifying scarcely monitored zones within the groundwater system boundaries. The steps are the following: I. Define aquifer boundaries, number and location of the existing monitoring sites and number and location of candidate new monitoring sites. Any constraint about the network size, and wells' location and characteristics need also to be identified at this step; II. Carry out stochastic simulations producing a large number of possible realizations of the improved monitoring network and choose the transient

  3. Locating the Binding Sites of Pb(II) Ion with Human and Bovine Serum Albumins

    PubMed Central

    Belatik, Ahmed; Hotchandani, Surat; Carpentier, Robert; Tajmir-Riahi, Heidar-Ali

    2012-01-01

    Lead is a potent environmental toxin that has accumulated above its natural level as a result of human activity. Pb cation shows major affinity towards protein complexation and it has been used as modulator of protein-membrane interactions. We located the binding sites of Pb(II) with human serum (HSA) and bovine serum albumins (BSA) at physiological conditions, using constant protein concentration and various Pb contents. FTIR, UV-visible, CD, fluorescence and X-ray photoelectron spectroscopic (XPS) methods were used to analyse Pb binding sites, the binding constant and the effect of metal ion complexation on HSA and BSA stability and conformations. Structural analysis showed that Pb binds strongly to HSA and BSA via hydrophilic contacts with overall binding constants of KPb-HSA = 8.2 (±0.8)×104 M−1 and KPb-BSA = 7.5 (±0.7)×104 M−1. The number of bound Pb cation per protein is 0.7 per HSA and BSA complexes. XPS located the binding sites of Pb cation with protein N and O atoms. Pb complexation alters protein conformation by a major reduction of α-helix from 57% (free HSA) to 48% (metal-complex) and 63% (free BSA) to 52% (metal-complex) inducing a partial protein destabilization. PMID:22574219

  4. Map showing drainage basins and locations of streamflow-measuring sites, Fairfax County, Virginia

    USGS Publications Warehouse

    Mohler, E.H.

    1977-01-01

    A drainage basin map of Fairfax County shows basins for named streams with drainage areas of 1.1 sq mi (2.8 sq km) or more. Areas of minor streams draining directly into the Potomac River and Occoquan Creek are tabulated. The locations of continuous-record and partial-record (peak-flow and low-flow) flow sites are shown. The use of topographic and climatic characteristics of drainage basins to transfer flow data from gaged areas to ungaged areas is discussed. (Woodard-USGS)

  5. Medial Tibial Stress Syndrome: Muscles Located at the Site of Pain.

    PubMed

    Brown, Ato Ampomah

    2016-01-01

    Objective. The purpose of this study was to examine the relationship between the location of the MTSS pain (posteromedial border of tibia) and the muscles that originate from that site. Method. The study was conducted in the Department of Anatomy of the School of Medical Sciences, University of Cape Coast, and involved the use of 22 cadaveric legs (9 paired and 4 unpaired) from 11 males and 2 females. Findings. The structures that were thus observed to attach directly to the posteromedial border of the tibia were the soleus, the flexor digitorum longus, and the deep crural fascia. The soleus and flexor digitorum longus muscles were observed to attach directly to the posteromedial border of the tibia. The tibialis posterior muscle had no attachment to this site. Conclusion. The findings of this study suggest that if traction is the cause of MTSS then soleus and the flexor digitorum muscles and not the tibialis posterior muscle are the likely cause of MTSS. PMID:27066291

  6. Medial Tibial Stress Syndrome: Muscles Located at the Site of Pain

    PubMed Central

    Brown, Ato Ampomah

    2016-01-01

    Objective. The purpose of this study was to examine the relationship between the location of the MTSS pain (posteromedial border of tibia) and the muscles that originate from that site. Method. The study was conducted in the Department of Anatomy of the School of Medical Sciences, University of Cape Coast, and involved the use of 22 cadaveric legs (9 paired and 4 unpaired) from 11 males and 2 females. Findings. The structures that were thus observed to attach directly to the posteromedial border of the tibia were the soleus, the flexor digitorum longus, and the deep crural fascia. The soleus and flexor digitorum longus muscles were observed to attach directly to the posteromedial border of the tibia. The tibialis posterior muscle had no attachment to this site. Conclusion. The findings of this study suggest that if traction is the cause of MTSS then soleus and the flexor digitorum muscles and not the tibialis posterior muscle are the likely cause of MTSS. PMID:27066291

  7. The "Simeiz-Katzively" co-location site of space geodesy techniques: current state and future activity

    NASA Astrophysics Data System (ADS)

    Yatskiv, Y.; Odynets, P.; Volvach, O.

    2014-12-01

    Two Satellite Laser Ranging (SLR) stations, two Global Navigation Satellite System (GNSS) stations and Very Long Base Interferometry (VLBI) station are placed on the "Simeiz-Katzively" co-location site. The activity of these space geodesy techniques in 2010-2012 is presented. Special attention is paid on results of new local tie surveys at this co-location site.

  8. Analytical studies on a new lattice hydrodynamic traffic flow model with consideration of traffic current cooperation among three consecutive sites

    NASA Astrophysics Data System (ADS)

    Li, Zhipeng; Zhong, Chenjie; Chen, Lizhu; Xu, Shangzhi; Qian, Yeqing

    2016-09-01

    In this paper, the original lattice hydrodynamic model of traffic flow is extended to take into account the traffic current cooperation among three consecutive sites. The basic idea of the new consideration is that the cooperative traffic current of the considered site is determined by the traffic currents of the site itself, the immediately preceding site and the immediately following one. The stability criterion of the extended model is obtained by applying the linear stability analysis. The result reveals the traffic current cooperation of the immediately preceding site is positive correlation with the stability of traffic system, while negative correlation is found between the traffic stability and the traffic current cooperation of the nearest follow site. To describe the phase transition, the modified KdV equation near the critical point is derived by using the reductive perturbation method, with obtaining the dependence of the propagation kink solution for traffic jams on the traffic current cooperation among three consecutive sites. The direct numerical are conducted to verify the results of theoretical analysis, and explore the effects of the traffic current cooperation on the traffic flux of the vehicle flow system.

  9. MPL-Net Measurements of Aerosol and Cloud Vertical Distributions at Co-Located AERONET Sites

    NASA Technical Reports Server (NTRS)

    Welton, Ellsworth J.; Campbell, James R.; Berkoff, Timothy A.; Spinhirne, James D.; Tsay, Si-Chee; Holben, Brent; Starr, David OC. (Technical Monitor)

    2002-01-01

    In the early 1990s, the first small, eye-safe, and autonomous lidar system was developed, the Micropulse Lidar (MPL). The MPL acquires signal profiles of backscattered laser light from aerosols and clouds. The signals are analyzed to yield multiple layer heights, optical depths of each layer, average extinction-to-backscatter ratios for each layer, and profiles of extinction in each layer. In 2000, several MPL sites were organized into a coordinated network, called MPL-Net, by the Cloud and Aerosol Lidar Group at NASA Goddard Space Flight Center (GSFC) using funding provided by the NASA Earth Observing System. tn addition to the funding provided by NASA EOS, the NASA CERES Ground Validation Group supplied four MPL systems to the project, and the NASA TOMS group contributed their MPL for work at GSFC. The Atmospheric Radiation Measurement Program (ARM) also agreed to make their data available to the MPL-Net project for processing. In addition to the initial NASA and ARM operated sites, several other independent research groups have also expressed interest in joining the network using their own instruments. Finally, a limited amount of EOS funding was set aside to participate in various field experiments each year. The NASA Sensor Intercomparison and Merger for Biological and Interdisciplinary Oceanic Studies (SIMBIOS) project also provides funds to deploy their MPL during ocean research cruises. All together, the MPL-Net project has participated in four major field experiments since 2000. Most MPL-Net sites and field experiment locations are also co-located with sunphotometers in the NASA Aerosol Robotic Network. (AERONET). Therefore, at these locations data is collected on both aerosol and cloud vertical structure as well as column optical depth and sky radiance. Real-time data products are now available from most MPL-Net sites. Our real-time products are generated at times of AERONET aerosol optical depth (AOD) measurements. The AERONET AOD is used as input to our

  10. External location of sites on pig erythrocyte membranes that bind nitrobenzylthioinosine

    SciTech Connect

    Agbanyo, F.R.; Cass, C.E.; Paterson, A.R.

    1988-03-01

    Nucleoside transport in erythrocytes of various species is inhibited by the binding of nitrobenzylthioinosine (NBMPR) to high affinity sites associated with nucleoside transport elements of the plasma membrane. The present study examined binding of (/sup 3/H)NBMPR to unsealed ghosts and to sealed right-side-out vesicles (ROVs) and inside-out vesicles (IOVs) prepared from pig erythrocytes. Kd values for NBMPR dissociation from the ligand-site complex in unsealed ghosts, ROVs and IOVs were similar (1.6-2.4 nM), and Bmax values (mean +/- SD) were, respectively, 22.2 +/- 5.5, 25.8 +/- 6.4, and 37.3 +/- 4.0 molecules/fg of protein, reflecting differences in the protein content of the membrane preparations. When temperatures were decreased from 22 degrees to 4 degrees, NBMPR binding to erythrocyte membrane preparations was reduced in IOVs relative to that in unsealed ghosts and ROVs. At 22 degrees, the association of NBMPR molecules with IOVs was slower than with ROVs and unsealed ghosts, differences that were virtually eliminated by permeabilization of the membrane preparations with saponin. Thus, the binding sites were more accessible to external NBMPR in sealed ROVs and unsealed ghosts than in sealed IOVs, indicating that the NBMPR sites are located on the extracellular aspect of the membrane.

  11. Informing geobiology through GIS site suitability analysis: locating springs in mantle units of ophiolites

    NASA Astrophysics Data System (ADS)

    Bowman, A.; Cardace, D.; August, P.

    2012-12-01

    Springs sourced in the mantle units of ophiolites serve as windows to the deep biosphere, and thus hold promise in elucidating survival strategies of extremophiles, and may also inform discourse on the origin of life on Earth. Understanding how organisms can survive in extreme environments provides clues to how microbial life responds to gradients in pH, temperature, and oxidation-reduction potential. Spring locations associated with serpentinites have traditionally been located using a variety of field techniques. The aqueous alteration of ultramafic rocks to serpentinites is accompanied by the production of very unusual formation fluids, accessed by drilling into subsurface flow regimes or by sampling at related surface springs. The chemical properties of these springs are unique to water associated with actively serpentinizing rocks; they reflect a reducing subsurface environment reacting at low temperatures producing high pH, Ca-rich formation fluids with high dissolved hydrogen and methane. This study applies GIS site suitability analysis to locate high pH springs upwelling from Coast Range Ophiolite serpentinites in Northern California. We used available geospatial data (e.g., geologic maps, topography, fault locations, known spring locations, etc.) and ArcGIS software to predict new spring localities. Important variables in the suitability model were: (a) bedrock geology (i.e., unit boundaries and contacts for peridotite, serpentinite, possibly pyroxenite, or chromite), (b) fault locations, (c) regional data for groundwater characteristics such as pH, Ca2+, and Mg2+, and (d) slope-aspect ratio. The GIS model derived from these geological and environmental data sets predicts the latitude/longitude points for novel and known high pH springs sourced in serpentinite outcrops in California. Field work confirms the success of the model, and map output can be merged with published environmental microbiology data (e.g., occurrence of hydrogen-oxidizers) to showcase

  12. A Novel and Efficient Tool for Locating and Characterizing Protein Cavities and Binding Sites

    PubMed Central

    Tripathi, Ashutosh; Kellogg, Glen E.

    2009-01-01

    Systematic investigation of a protein and its binding site characteristics are crucial for designing small molecules that modulate protein functions. However, fundamental uncertainties in binding site interactions and insufficient knowledge of the properties of even well-defined binding pockets can make it difficult to design optimal drugs. Herein, we report the development and implementation of a cavity detection algorithm built with HINT toolkit functions that we are naming VICE (Vectorial Identification of Cavity Extents). This very efficient algorithm is based on geometric criteria applied to simple integer grid maps. In testing, we carried out a systematic investigation on a very diverse data set of proteins and protein-protein/protein-polynucleotide complexes for locating and characterizing the indentations, cavities, pockets, grooves, channels and surface regions. Additionally, we evaluated a curated data set of unbound proteins for which a ligand-bound protein structures are also known; here the VICE algorithm located the actual ligand in the largest cavity in 83% of the cases and in one of the three largest in 90% of the cases. An interactive front-end provides a quick and simple procedure for locating, displaying and manipulating cavities in these structures. Information describing the cavity, including its volume and surface area metrics, and lists of atoms, residues and/or chains lining the binding pocket, can be easily obtained and analyzed. For example, the relative cross-sectional surface area (to total surface area) of cavity openings in well-enclosed cavities is 0.06 ± 0.04 and in surface clefts or crevices is 0.25 ± 0.09. PMID:19847777

  13. Location of active transmission sites of Schistosoma japonicum in lake and marshland regions in China.

    PubMed

    Zhang, Z J; Carpenter, T E; Lynn, H S; Chen, Y; Bivand, R; Clark, A B; Hui, F M; Peng, W X; Zhou, Y B; Zhao, G M; Jiang, Q W

    2009-06-01

    Schistosomiasis control in China has, in general, been very successful during the past several decades. However, the rebounding of the epidemic situation in some areas in recent years raises concerns about a sustainable control strategy of which locating active transmission sites (ATS) is a necessary first step. This study presents a systematic approach for locating schistosomiasis ATS by combining the approaches of identifying high risk regions for schisotosmiasis and extracting snail habitats. Environmental, topographical, and human behavioural factors were included in the model. Four significant high-risk regions were detected and 6 ATS were located. We used the normalized difference water index (NDWI) combined with the normalized difference vegetation index (NDVI) to extract snail habitats, and the pointwise 'P-value surface' approach to test statistical significance of predicted disease risk. We found complicated non-linear relationships between predictors and schistosomiasis risk, which might result in serious biases if data were not properly treated. We also found that the associations were related to spatial scales, indicating that a well-designed series of studies were needed to relate the disease risk with predictors across various study scales. Our approach provides a useful tool, especially in the field of vector-borne or environment-related diseases. PMID:19416552

  14. Locating the binding sites of antitumor drug tamoxifen and its metabolites with DNA.

    PubMed

    Bourassa, P; Thomas, T J; Tajmir-Riahi, H A

    2014-07-01

    We located the binding sites of antitumor drugs tamoxifen, 4-hydroxytamoxifen and endoxifen with calf-thymus DNA. FTIR, CD, UV-vis and fluorescence spectroscopic methods as well as molecular modeling were used to characterize the drug binding sites, binding constant and the effect of drug binding on DNA stability and conformation. Structural analysis showed that tamoxifen and its metabolites bind DNA via hydrophobic and hydrophilic interactions with overall binding constants of K(tam-DNA)=3.5 (±0.2)×10⁴ M⁻¹, K(4-hydroxytam-DNA)=3.3 (±0.4) × 10⁴ M⁻¹ and K(endox)-DNA=2.8 (±0.8)×10⁴ M⁻¹. The number of binding sites occupied by drug is 1 (tamoxifen), 0.8 (4-hydroxitamoxifen) and 1.2 (endoxifen). Docking showed the participation of several nucleobases in drug-DNA complexes with the free binding energy of -3.85 (tamoxifen), -4.18 (4-hydroxtamoxifen) and -3.74 kcal/mol (endoxifen). The order of binding is 4-hydroxy-tamoxen>tamoxifen>endoxifen. Drug binding did not alter DNA conformation from B-family structure, while major biopolymer aggregation occurred at high drug concentrations. The drug binding mode is correlated with the mechanism of action of antitumor activity of tamoxifen and its metabolites. PMID:24682017

  15. Lattice site investigations for Mg in LiNbO 3 by combined RBS-PIXE-NRA channeling experiments

    NASA Astrophysics Data System (ADS)

    Kling, A.; Kollewe, D.; Grabmaier, B. C.

    1992-02-01

    The lattice position of magnesium in lithium niobate has been investigated for single crystals doped with MgO (between 0 and 9 mol% in the congruent melt) using a combination of RBS, PIXE and NRA with channeling. Mg seems to be collinear with the niobium and lithium in the c-axis for the whole concentration range. Concentration dependent effects with a threshold of about 1 mol% MgO for other axes have been observed. For low concentrations experimental results and computer simulations performed with our recently developed program CASSIS indicate that magnesium occupies an octahedral site near lithium while for higher concentrations the regular lithium site and an octahedral position near niobium is found to be occupied.

  16. Solution of a model of self-avoiding walks with multiple monomers per site on the Bethe lattice.

    PubMed

    Serra, Pablo; Stilck, Jürgen F

    2007-01-01

    We solve a model of self-avoiding walks with up to two monomers per site on the Bethe lattice. This model, inspired in the Domb-Joyce model, was recently proposed to describe the collapse transition observed in interacting polymers [J. Krawczyk, Phys. Rev. Lett. 96, 240603 (2006)]. When immediate self-reversals are allowed (reversion-allowed model), the solution displays a phase diagram with a polymerized phase and a nonpolymerized phase, separated by a phase transition which is of first order for a nonvanishing statistical weight of doubly occupied sites. If the configurations are restricted forbidding immediate self-reversals (reversion-forbidden model), a richer phase diagram with two distinct polymerized phases is found, displaying a tricritical point and a critical end point. PMID:17358133

  17. Selected stratigraphic data for drill holes located in Frenchman Flat, Nevada Test Site. Rev. 1

    SciTech Connect

    Drellack, S.L. Jr.

    1997-02-01

    Stratigraphic data are presented in tabular form for 72 holes drilled in Frenchman Flat, Nevada Test Site, between 1950 and 1993. Three pairs of data presentations are included for each hole: depth to formation tops, formation thicknesses, and formation elevations are presented in both field (English) and metric units. Also included for each hole, where available, are various construction data (hole depth, hole diameter, surface location coordinates) and certain information of hydrogeologic significance (depth to water level, top of zeolitization). The event name is given for holes associated with a particular nuclear test. An extensive set of footnotes is included, which indicates data sources and provides other information. The body of the report describes the stratigraphic setting of Frenchman Flat, gives drill-hole naming conventions and database terminology, and provides other background and reference material.

  18. Preliminary geohydrologic site characterization and proposed water quality well locations for WAG 4, WAG 5, WAG 3, and SWSA 1

    SciTech Connect

    Baughn, D.C.

    1987-03-01

    The purpose of this report is to assess general site conditions and to recommend water quality well locations at Waste Area Groupings (WAGs) 4, 5 and 3 and Solid Waste Storage Area 1 (SWSA 1) within the Oak Ridge National Laboratory (ORNL) complex. The subject sites are identified on the general site location map. For reference, the relationship of the subject sites to other WAGs are shown. WAGs are regions prescribed by Martin Marietta throughout the ORNL complex that require environmental assessment which will include design and installation of ground water monitoring systems. WAGs contain solid waste management units such as SWSAs, as well as pipelines, spill sites, buildings, ponds and experimental test sites. These solid waste management units are considered to be potential sources of contamination requiring further evaluation. This report recommends locations for water quality wells which will be installed at WAG boundaries in order to gather water quality data.

  19. Intrasite motions and monument instabilities at Medicina ITRF co-location site

    NASA Astrophysics Data System (ADS)

    Sarti, Pierguido; Abbondanza, Claudio; Legrand, Juliette; Bruyninx, Carine; Vittuari, Luca; Ray, Jim

    2013-03-01

    We process the total-station surveys performed at the ITRF co-location site Medicina (Northern Italy) over the decade (2001-2010) with the purpose of determining the extent of local intrasite motions and relating them to local geophysical processes, the geological setting and the design of the ground pillars. In addition, continuous observations acquired by two co-located GPS stations (MEDI and MSEL separated by ≈27 m) are analysed and their relative motion is cross-checked with the total-station results. The local ground control network extends over a small area (<100 × 100 m) but the results demonstrate significant anisotropic deformations with rates up to 1.6 mm a-1, primarily horizontal, a value comparable to intraplate tectonic deformations. The results derived from GPS and total-station observations are consistent and point to the presence of horizontal intrasite motions over very short distances possibly associated with varying environmental conditions in a very unfavourable local geological setting and unsuitable monument design, these latter being crucial aspects of the realization and maintenance of global permanent geodetic networks and the global terrestrial reference frame.

  20. Locating the binding sites of antioxidants resveratrol, genistein and curcumin with tRNA.

    PubMed

    N'soukpoé-Kossi, C N; Bourassa, P; Mandeville, J S; Bekale, L; Bariyanga, J; Tajmir-Riahi, H A

    2015-09-01

    We located the binding sites of antioxidants resveratrol, genistein and curcumin on tRNA in aqueous solution at physiological conditions using constant tRNA concentration and various polyphenol contents. FTIR, UV-visible, CD spectroscopic methods and molecular modeling were used to determine polyphenol binding sites, the binding constant and the effects of polyphenol complexation on tRNA conformation and particle formation. Structural analysis showed that polyphenols bind tRNA via G-C and A-U base pairs through hydrophilic, hydrophobic and H-bonding contacts with overall binding constants of K(res-tRNA)=8.95(±0.80)×10(3) M(-1), K(gen-tRNA)=3.07(±0.5)×10(3) M(-1) and K(cur-tRNA)=1.55(±0.3)×10(4) M(-1). Molecular modeling showed the participation of several nucleobases in polyphenol-tRNA adduct formation with free binding energy of -4.43 for resveratrol, -4.26 kcal/mol for genistein and -4.84 kcal/mol for curcumin, indicating that the interaction process is spontaneous at room temperature. While tRNA remains in A-family structure, major biopolymer aggregation and particle formation occurred at high polyphenol contents. PMID:26093317

  1. Location Capability and Site Characterization Installing a Borehole VBB Seismometer: the OGS Experience in Ferrara (Italy)

    NASA Astrophysics Data System (ADS)

    Pesaresi, D.; Barnaba, C.

    2014-12-01

    The Centro di Ricerche Sismologiche (CRS, Seismological Research Centre) of the Istituto Nazionale di Oceanografia e di Geofisica Sperimentale (OGS, Italian National Institute for Oceanography and Experimental Geophysics) in Udine (Italy) after the strong earthquake of magnitude M=6.4 occurred in 1976 in the Italian Friuli-Venezia Giulia region, started to operate the Northeastern Italy Seismic Network: it currently consists of 19 very sensitive broad band and 17 simpler short period seismic stations, all telemetered to and acquired in real time at the OGS CRS data centre in Udine. The southwestern edge of the OGS seismic network stands on the Po alluvial basin: earthquake localization and characterization in this area is affected by the presence of soft alluvial deposits. Following the ML=5.9 earthquake that struck the Emilia region around Ferrara in Northern Italy on May 20, 2012, a cooperation of Istituto Nazionale di Geofisica e Vulcanologia, OGS, the Comune di Ferrara and the University of Ferrara lead to the reinstallation of a previously existing very broad band (VBB) borehole seismic station in Ferrara and to the deployment of a temporary seismographic network consisting of eight portable seismological stations, to record the local earthquakes that occurred during the seismic sequence. The aim of the OGS intervention was on one hand to extend its real time seismic monitoring capabilities toward South-West, including Ferrara and its surroundings, and on the other hand to evaluate seismic site responses in the area. We will introduce details of the Ferrara VBB borehole station and the OGS temporary seismographic network configuration and installation. We will then illustrate the location capability performances, and finally we will shortly describe seismic site characterization with surface/borehole comparisons in terms of seismic noise, site amplification and resonance frequencies.

  2. Hydrologic modelings/GIS as an aid in locating monitoring sites

    SciTech Connect

    Rosenthal, W.D.; Hoffman, D.W.

    1999-12-01

    With the increasing importance and awareness of non-point source pollution, critical siting of water quality monitoring stations becomes important. Within large watersheds this siting becomes difficult because of the time and expense to travel the entire watershed and evaluate the area. Previous work has shown that hydrologic models can assist in evaluating water quality in large watersheds. In this study, the hydrologic model SWAT (Soil and Water Assessment Tool) was used to simulate flows, sediment and nutrient loadings on a 9,000 km{sup 2} watershed in central Texas for the period 1970--1984. The model is a continuous, daily time step model that predicts surface runoff, percolation, lateral subsurface flow, groundwater flow, transmission losses and flood routing. The Geographic Resources Analysis Support System (GRASS) and available Natural Resources Conservation Service databases provided input into SWAT. Subwatersheds demonstrating areas of highest per acre loadings were identified from model output. Modeled output of streamflow, nitrogen, phosphorus, and sediment loadings were analyzed. For 1972--1974, the correlation coefficient between observed and simulated streamflow was 0.83, while the Nash-Sutcliffe coefficient was 0.57 indicating the model is a better predictor than using the mean. Average annual loads from the entire basin were 3.9 kg ha{sup {minus}1} NO{sub 3} and 0.03 kg ha{sup {minus}1} soluble P. Subwatersheds in the lower part of the watershed had loads which were higher than the watershed average and as a result monitoring stations have been installed. The results demonstrate that a hydrologic model and available spatial databases can be used to aid in locating sites.

  3. Records for the number of distinct sites visited by a random walk on the fully connected lattice

    NASA Astrophysics Data System (ADS)

    Turban, Loïc

    2015-11-01

    We consider a random walk on the fully connected lattice with N sites and study the time evolution of the number of distinct sites s visited by the walker on a subset with n sites. A record value v is obtained for s at a record time t when the walker visits a site of the subset for the first time. The record time t is a partial covering time when v\\lt n and a total covering time when v = n. The probability distributions for the number of records s, the record value v and the record (covering) time t, involving r-Stirling numbers, are obtained using generating function techniques. The mean values, variances and skewnesses are deduced from the generating functions. In the scaling limit the probability distributions for s and v lead to the same Gaussian density. The fluctuations of the record time t are also Gaussian at partial covering, when n-v={{O}}(n). They are distributed according to the type-I Gumbel extreme-value distribution at total covering, when v = n. A discrete sequence of generalized Gumbel distributions, indexed by n-v, is obtained at almost total covering, when n-v={{O}}(1). These generalized Gumbel distributions are crossing over to the Gaussian distribution when n - v increases.

  4. Use of Loran-C navigation system to accurately determine sampling site location in an above ground cooling reservoir

    SciTech Connect

    Lockwood, R.E.; Blankinship, D.R.

    1994-12-31

    Environmental monitoring programs often require accurate determination of sampling site locations in aquatic environments. This is especially true when a {open_quotes}picture{close_quotes} of high resolution is needed for observing a changing variable in a given area and location is assumed to be important to the distribution of that variable. Sample site location can be difficult if few visible land marks are available for reference on a large body of water. The use of navigational systems such as Global Positioning System (GPS) and its predecessor, Loran-C, provide an excellent method for sample site location. McFarland (1992) discusses the practicality of GPS for location determination. This article discusses the use of Loran-C in a sampling scheme implemented at the South Texas Project Electrical Generating Station (STPEGS), Wadsworth, Texas.

  5. Two-Dimensional Pnictogen Honeycomb Lattice: Structure, On-Site Spin-Orbit Coupling and Spin Polarization

    PubMed Central

    Lee, Jason; Tian, Wen-Chuan; Wang, Wei-Liang; Yao, Dao-Xin

    2015-01-01

    Because of its novel physical properties, two-dimensional materials have attracted great attention. From first-principle calculations and vibration frequencies analysis, we predict a new family of two-dimensional materials based on the idea of octet stability: honeycomb lattices of pnictogens (N, P, As, Sb, Bi). The buckled structures of materials come from the sp3 hybridization. These materials have indirect band gap ranging from 0.43 eV to 3.7 eV. From the analysis of projected density of states, we argue that the s and p orbitals together are sufficient to describe the electronic structure under tight-binding model, and the tight-binding parameters are obtained by fitting the band structures to first-principle results. Surprisingly large on-site spin-orbit coupling is found for all the pnictogen lattices except nitrogen. Investigation on the electronic structures of both zigzag and armchair nanoribbons reveals the possible existence of spin-polarized ferromagnetic edge states in some cases, which are rare in one-dimensional systems. These edge states and magnetism may exist under the condition of high vacuum and low temperature. This new family of materials would have promising applications in electronics, optics, sensors, and solar cells. PMID:26122870

  6. Two-Dimensional Pnictogen Honeycomb Lattice: Structure, On-Site Spin-Orbit Coupling and Spin Polarization.

    PubMed

    Lee, Jason; Tian, Wen-Chuan; Wang, Wei-Liang; Yao, Dao-Xin

    2015-01-01

    Because of its novel physical properties, two-dimensional materials have attracted great attention. From first-principle calculations and vibration frequencies analysis, we predict a new family of two-dimensional materials based on the idea of octet stability: honeycomb lattices of pnictogens (N, P, As, Sb, Bi). The buckled structures of materials come from the sp(3) hybridization. These materials have indirect band gap ranging from 0.43 eV to 3.7 eV. From the analysis of projected density of states, we argue that the s and p orbitals together are sufficient to describe the electronic structure under tight-binding model, and the tight-binding parameters are obtained by fitting the band structures to first-principle results. Surprisingly large on-site spin-orbit coupling is found for all the pnictogen lattices except nitrogen. Investigation on the electronic structures of both zigzag and armchair nanoribbons reveals the possible existence of spin-polarized ferromagnetic edge states in some cases, which are rare in one-dimensional systems. These edge states and magnetism may exist under the condition of high vacuum and low temperature. This new family of materials would have promising applications in electronics, optics, sensors, and solar cells. PMID:26122870

  7. Two-Dimensional Pnictogen Honeycomb Lattice: Structure, On-Site Spin-Orbit Coupling and Spin Polarization

    NASA Astrophysics Data System (ADS)

    Lee, Jason; Tian, Wen-Chuan; Wang, Wei-Liang; Yao, Dao-Xin

    2015-06-01

    Because of its novel physical properties, two-dimensional materials have attracted great attention. From first-principle calculations and vibration frequencies analysis, we predict a new family of two-dimensional materials based on the idea of octet stability: honeycomb lattices of pnictogens (N, P, As, Sb, Bi). The buckled structures of materials come from the sp3 hybridization. These materials have indirect band gap ranging from 0.43 eV to 3.7 eV. From the analysis of projected density of states, we argue that the s and p orbitals together are sufficient to describe the electronic structure under tight-binding model, and the tight-binding parameters are obtained by fitting the band structures to first-principle results. Surprisingly large on-site spin-orbit coupling is found for all the pnictogen lattices except nitrogen. Investigation on the electronic structures of both zigzag and armchair nanoribbons reveals the possible existence of spin-polarized ferromagnetic edge states in some cases, which are rare in one-dimensional systems. These edge states and magnetism may exist under the condition of high vacuum and low temperature. This new family of materials would have promising applications in electronics, optics, sensors, and solar cells.

  8. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    NASA Astrophysics Data System (ADS)

    Sexton, E. A.; Snelson, C. M.; Chipman, V.; Emer, D. F.; White, R. L.; Emmitt, R.; Wright, A. A.; Drellack, S.; Huckins-Gang, H.; Mercadante, J.; Floyd, M.; McGowin, C.; Cothrun, C.; Bonal, N.

    2013-12-01

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined. For Phase II of the experiment, characterization of the location is required to develop the geologic/geophysical models for the execution of the experiment. Criteria for the location are alluvium thickness of approximately 170 m and a water table below 170 m; minimal fracturing would be ideal. A P-wave mini-vibroseis survey was conducted at a potential site in alluvium to map out the subsurface geology. The seismic reflection profile consisted of 168 geophone stations, spaced 5 m apart. The mini-vibe was a 7,000-lb peak-force source, starting 57.5 m off the north end of the profile and ending 57.5 m past the southern-most geophone. The length of the profile was 835 m. The source points were placed every 5 m, equally spaced between geophones to reduce clipping. The vibroseis sweep was from 20 Hz down to 180 Hz over 8 seconds, and four sweeps were stacked at each shot location. The shot gathers show high signal-to-noise ratios with clear first arrivals across the entire spread and the suggestion of some shallow reflectors. The data were

  9. The nuclear quadrupole interaction at inequivalent lattice sites in ammonium paramolybdate: A TDPAC study

    NASA Astrophysics Data System (ADS)

    Das, S. K.; Heinrich, F.; Butz, T.

    2006-09-01

    A nuclear quadrupole interaction (NQI) study using the time differential perturbed angular correlation (TDPAC) technique on ammonium paramolybdate (APM) has shown three inequivalent molybdenum sites in this compound which consists of seven MoO 6 polyhedra connected through edges. In this study the nuclear probe 99Mo was used to measure the γ- γ perturbed angular correlation of 99Tc on Mo-sites to obtain the quadrupole interaction parameters. The quadrupole interaction frequencies ( ωQ) for the three sites are 0.0224, 0.0386 and 0.0434 rad/ns and the asymmetry parameters ( η) of the electric field gradient (EFG) are 0.45, 0.18, and 0.58, respectively. The site assignment is based on the population ratios 4:2:1. The Mo atoms with the highest population show the lowest ωQ indicating that this set of polyhedra is "least" distorted or condensed. Besides the least squares fit, a cross-correlation algorithm has been used to analyze the experimental data to corroborate the fitted parameters and quoted errors. The derived NQI-parameters can be used for site assignments in other compounds built from condensed Mo-O octahedra.

  10. On the development of a model predicting the recrystallization texture of aluminum using the Taylor model for rolling textures and the coincidence lattice site theory

    NASA Astrophysics Data System (ADS)

    T, Morimoto; F, Yoshida; A, Yanagida; J, Yanagimoto

    2015-04-01

    First, hardening model in f.c.c. metals was formulated with collinear interactions slips, Hirth slips and Lomer-Cottrell slips. Using the Taylor and the Sachs rolling texture prediction model, the residual dislocation densities of cold-rolled commercial pure aluminum were estimated. Then, coincidence site lattice grains were investigated from observed cold rolling texture. Finally, on the basis of oriented nucleation theory and coincidence site lattice theory, the recrystallization texture of commercial pure aluminum after low-temperature annealing was predicted.

  11. Location, Location, Location!

    ERIC Educational Resources Information Center

    Ramsdell, Kristin

    2004-01-01

    Of prime importance in real estate, location is also a key element in the appeal of romances. Popular geographic settings and historical periods sell, unpopular ones do not--not always with a logical explanation, as the author discovered when she conducted a survey on this topic last year. (Why, for example, are the French Revolution and the…

  12. Radioecological characterization of a uranium mining site located in a semi-arid region in Brazil.

    PubMed

    Fernandes, Horst M; Lamego Simoes Filho, F Fernando; Perez, Valeska; Franklin, Mariza Ramalho; Gomiero, Luiz Alberto

    2006-01-01

    The work presents the radioecological characterization of the new Brazilian uranium mining and milling site located in a semi-arid region of the country. The process characterization demonstrated that in heap leach plants most of the 226Ra remains in the leached ore. Despite the potential higher availability of radium isotopes in the soils of the studied region the lack of precipitation in that area reduces the leaching/mobilization of the radionuclides. High 226Ra and 228Ra concentrations were found in manioc while 210Pb was significant in pasture. It was suggested that a range from 10(-3) to 10(-1) may conveniently encompass most of the transfer factors (TF) values for soil/plant systems (i.e. involving different cultures, different soils and natural radionuclides). Impacts due to aerial transportation of aerosols and radon generated in the mining were proved to be minimal and restricted to an area not greater than 15 km2. Finally, uranium complexation by carbonates was shown to be the main mechanism responding for the elevated radionuclide concentration in groundwater. PMID:16545512

  13. Motif types, motif locations and base composition patterns around the RNA polyadenylation site in microorganisms, plants and animals

    PubMed Central

    2014-01-01

    Background The polyadenylation of RNA is critical for gene functioning, but the conserved sequence motifs (often called signal or signature motifs), motif locations and abundances, and base composition patterns around mRNA polyadenylation [poly(A)] sites are still uncharacterized in most species. The evolutionary tendency for poly(A) site selection is still largely unknown. Results We analyzed the poly(A) site regions of 31 species or phyla. Different groups of species showed different poly(A) signal motifs: UUACUU at the poly(A) site in the parasite Trypanosoma cruzi; UGUAAC (approximately 13 bases upstream of the site) in the alga Chlamydomonas reinhardtii; UGUUUG (or UGUUUGUU) at mainly the fourth base downstream of the poly(A) site in the parasite Blastocystis hominis; and AAUAAA at approximately 16 bases and approximately 19 bases upstream of the poly(A) site in animals and plants, respectively. Polyadenylation signal motifs are usually several hundred times more abundant around poly(A) sites than in whole genomes. These predominant motifs usually had very specific locations, whether upstream of, at, or downstream of poly(A) sites, depending on the species or phylum. The poly(A) site was usually an adenosine (A) in all analyzed species except for B. hominis, and there was weak A predominance in C. reinhardtii. Fungi, animals, plants, and the protist Phytophthora infestans shared a general base abundance pattern (or base composition pattern) of “U-rich—A-rich—U-rich—Poly(A) site—U-rich regions”, or U-A-U-A-U for short, with some variation for each kingdom or subkingdom. Conclusion This study identified the poly(A) signal motifs, motif locations, and base composition patterns around mRNA poly(A) sites in protists, fungi, plants, and animals and provided insight into poly(A) site evolution. PMID:25052519

  14. Analysis of CDS-located miRNA target sites suggests that they can effectively inhibit translation

    PubMed Central

    Hausser, Jean; Syed, Afzal Pasha; Bilen, Biter; Zavolan, Mihaela

    2013-01-01

    Most of what is presently known about how miRNAs regulate gene expression comes from studies that characterized the regulatory effect of miRNA binding sites located in the 3′ untranslated regions (UTR) of mRNAs. In recent years, there has been increasing evidence that miRNAs also bind in the coding region (CDS), but the implication of these interactions remains obscure because they have a smaller impact on mRNA stability compared with miRNA-target interactions that involve 3′ UTRs. Here we show that miRNA-complementary sites that are located in both CDS and 3′-UTRs are under selection pressure and share the same sequence and structure properties. Analyzing recently published data of ribosome-protected fragment profiles upon miRNA transfection from the perspective of the location of miRNA-complementary sites, we find that sites located in the CDS are most potent in inhibiting translation, while sites located in the 3′ UTR are more efficient at triggering mRNA degradation. Our study suggests that miRNAs may combine targeting of CDS and 3′ UTR to flexibly tune the time scale and magnitude of their post-transcriptional regulatory effects. PMID:23335364

  15. A Brassica napus Lipase Locates at the Membrane Contact Sites Involved in Chloroplast Development

    PubMed Central

    Tan, Xiaoli; Wang, Qiuye; Tian, Baoxia; Zhang, Henan; Lu, Daoli; Zhou, Jia

    2011-01-01

    Background Fatty acids synthesized in chloroplast are transported to endoplasmic reticulum (ER) for triacylglycerols (TAGs) resembling. The development of chloroplast also requires lipids trafficking from ER to chloroplast. The membrane contact sites (MCSs) between ER and chloroplast has been demonstrated to be involved for the trafficking of lipids and proteins. Lipids trafficking between ER and chloroplast is often accompanied by lipids interconversion. However, it is rarely known how lipids interconversion happens during their trafficking. Methodology/Principal Findings We cloned a lipase gene from Brassica napus L., designated as BnCLIP1. Green fluorescence protein (GFP)-tagged BnCLIP1 was shown to locate at the MCSs between ER and chloroplasts in tobacco leaves. Heterogeneous expression of BnCLIP1 in Saccharomyces cerevisiae (pep4) reduced the total amount of fatty acid. Gas chromatography-mass spectrometry (GC-MS) analysis revealed that the truncated BnCLIP1 had a substrate preference for C16:0 lipids in Saccharomyces cerevisiae (pep4). To probe the physiological function of BnCLIP1, two Brassica napus lines with different oil-content were introduced to investigate the transcript patterns of BnCLIP1 during seed development. Intriguingly, the transcript level of BnCLIP1 was found to be immediately up-regulated during the natural seed senescence of both lines; the transcription response of BnCLIP1 in the high oil-content seeds was faster than the lower ones, suggesting a potential role of BnCLIP1 in affecting seed oil synthesis via regulating chloroplast integrity. Further researches showed that chemical disruption of leaf chloroplast also activated the transcription of BnCLIP1. Conclusions/Significance The findings of this study show that BnCLIP1 encodes a lipase, localizes at the MCSs and involves in chloroplast development. PMID:22046373

  16. Preliminary geohydrologic site characterization and proposed water quality well locations for WAG 7, WAG 8 and WAG 9

    SciTech Connect

    Baughn, D.C.

    1987-09-01

    The purpose of this report is to assess general site conditions and to recommend water quality well locations at three Waste Area Groupings (WAGS) within the Oak Ridge National Laboratory (ORNL) complex. The subject sites are WAGs 7, 8 and 9 each of which is identified on the general site location map. For reference, the relationship of the subject sites to other WAGs are shown. WAGs are regions prescribed by Martin Marietta throughout the ORNL complex that require environmental assessment. WAGs contain solid waste management units such as Solid Waste Storage Areas (SWSAs), as well as pipelines, spill sites, buildings, ponds and experimental test sites. These solid waste management units are considered to be potential sources of contamination. The WAG boundaries describe the areal limits of specific waste management operations as well as currently known areas of waste constituent migration. Because solid waste management units within WAGs 7, 8 and 9 may continue to release waste constituents to the environment, the existing groundwater monitoring systems is being upgraded. This report recommends locations for water quality wells which will be installed at these three WAG boundaries in order to gather water quality data. The proposed well locations are shown. Water quality well design coordinates (ORNL grid) and estimated completion depths are given.

  17. The impact of an efficient collection sites location on the zoning phase in municipal solid waste management

    SciTech Connect

    Ghiani, Gianpaolo Manni, Andrea Manni, Emanuele Toraldo, Massimiliano

    2014-11-15

    Highlights: • We study the problems of locating collection areas and zoning the service territory in a municipal waste management system. • We investigate the impact that an efficient collection sites location has on the subsequent zoning phase. • On a real-world test case, we show that the proposed approach could allow achieving significant monetary savings. - Abstract: In this paper, we study two decisional problems arising when planning the collection of solid waste, namely the location of collection sites (together with bin allocation) and the zoning of the service territory, and we assess the potential impact that an efficient location has on the subsequent zoning phase. We first propose both an exact and a heuristic approach to locate the unsorted waste collection bins in a residential town, and to decide the capacities and characteristics of the bins to be located at each collection site. A peculiar aspect we consider is that of taking into account the compatibility between the different types of bins when allocating them to collection areas. Moreover, we propose a fast and effective heuristic approach to identify homogeneous zones that can be served by a single collection vehicle. Computational results on data related to a real-life instance show that an efficient location is fundamental in achieving consistent monetary savings, as well as a reduced environmental impact. These reductions are the result of one vehicle less needed to perform the waste collection operations, and an overall traveled distance reduced by about 25% on the average.

  18. Experimental location of helium atoms in 6H-SiC crystal lattice after implantation and after annealing at 400 °C

    NASA Astrophysics Data System (ADS)

    Linez, F.; Garrido, F.; Erramli, H.; Sauvage, T.; Courtois, B.; Desgardin, P.; Barthe, M.-F.

    2015-04-01

    The question of the helium behavior in silicon carbide has been studied at the atomic scale by numerical simulations, but no experiment has been carried out to assess the results hitherto. This paper describes the first experiments allowing this comparison. 6H-SiC single crystals were implanted with 50-keV He ions at a fluence of 1015 He/cm2 at room temperature. The as-received and as-implanted samples were analyzed by RBS and NRA in channeling mode along the main crystallographic planes and across three main axes. The measurements have shown that a portion of the He is located in the interstitial tetrahedral sites as predicted by the numerical simulations. The same measurements were performed on an implanted sample subsequently annealed at 400 °C under Ar atmosphere. They have shown that the quantity of He detected in interstitial tetrahedral sites TSi and TC has not significantly changed whereas that of He detected in the main crystallographic plane and in the main axis has increased. This increase is likely caused by He atoms migration at 400 °C toward interstitial positions located inside vacancies such as VSi and VSiVC. In parallel a partial recovery of the Si and C sublattices has been observed.

  19. Sunflower (Helianthus annuus) pollination in California's Central Valley is limited by native bee nest site location.

    PubMed

    Sardiñas, Hillary S; Tom, Kathleen; Ponisio, Lauren Catherine; Rominger, Andrew; Kremen, Claire

    2016-03-01

    The delivery of ecosystem services by mobile organisms depends on the distribution of those organisms, which is, in turn, affected by resources at local and landscape scales. Pollinator-dependent crops rely on mobile animals like bees for crop production, and the spatial relationship between floral resources and nest location for these central-place foragers influences the delivery of pollination services. Current models that map pollination coverage in agricultural regions utilize landscape-level estimates of floral availability and nesting incidence inferred from expert opinion, rather than direct assessments. Foraging distance is often derived from proxies of bee body size, rather than direct measurements of foraging that account for behavioral responses to floral resource type and distribution. The lack of direct measurements of nesting incidence and foraging distances may lead to inaccurate mapping of pollination services. We examined the role of local-scale floral resource presence from hedgerow plantings on nest incidence of ground-nesting bees in field margins and within monoculture, conventionally managed sunflower fields in California's Central Valley. We tracked bee movement into fields using fluorescent powder. We then used these data to simulate the distribution of pollination services within a crop field. Contrary to expert opinion, we found that ground-nesting native bees nested both in fields and edges, though nesting rates declined with distance into field. Further, we detected no effect of field-margin floral enhancements on nesting. We found evidence of an exponential decay rate of bee movement into fields, indicating that foraging predominantly occurred in less than 1% of medium-sized bees' predicted typical foraging range. Although we found native bees nesting within agricultural fields, their restricted foraging movements likely centralize pollination near nest sites. Our data thus predict a heterogeneous distribution of pollination services

  20. Momentum, water vapor, and carbon dioxide exchange at a centrally located prairie site during FIFE

    NASA Astrophysics Data System (ADS)

    Verma, Shashi B.; Kim, Joon; Clement, Robert J.

    1992-11-01

    Eddy correlation measurements were made of fluxes of momentum, sensible heat, water vapor, and carbon dioxide at a centrally located plateau site in the FIFE study area during the period from May to October 1987. About 82% of the vegetation at the site was comprised of several C4 grass species (big bluestem, Indian grass, switchgrass, tall dropseed, little bluestem, and blue grama), with the remainder being C3 grasses, sedges, forbs, and woody plants. The prairie was burned in mid-April and was not grazed. Precipitation during the study period was about normal, except for a 3-week dry period in late July to early August, which caused moisture stress conditions. The drag coefficient (Cd=u*2/u¯2, where u* is the friction velocity and ū is the mean wind speed at 2.25 m above the ground) of the prairie vegetation ranged from 0.0087 to 0.0099. The average d/zc and z0/zc (where d is the zero plane displacement, z0 is the roughness parameter, and zc is the canopy height) were estimated to be about 0.71 and 0.028, respectively. Information was developed on the aerodynamic conductance (ga) in terms of mean wind speed (measured at a reference height) for different periods in the growing season. During the early and peak growth stages, with favorable soil moisture, the daily evapotranspiration (ET) rates ranged from 3.9 to 6.6 mm d-1. The ET rate during the dry period was between 2.9 and 3.8 mm d-1. The value of the Priestley-Taylor coefficient (α), calculated as the ratio of the measured ET to the equilibrium ET, averaged around 1.26 when the canopy stomatal resistance (rc) was less than 100 s m-1. When rc increased above 100 s m-1, α decreased rapidly. The atmospheric CO2 flux data (eddy correlation) were used, in conjunction with estimated soil CO2 flux, to evaluate canopy photosynthesis (Pc). The dependence of Pc on photosynthetically active radiation (KPAR), vapor pressure deficit, and soil moisture was examined. Under nonlimiting soil moisture conditions, Pc was

  1. Coincidence site lattice misorientations of crystals in orthorhombic systems, with application to YBa sub 2 Cu sub 3 O sub 7

    SciTech Connect

    Gertsman, V.Y. )

    1992-08-01

    In recent years many new materials have been involved in grain boundary studies. Many of them, have rather complex crystal lattices with low symmetry. For experimental studies and computer simulations of grain boundaries some theoretical tools are necessary. The main tool is the Coincidence Site Lattice (CSL) model, which has been successfully used for structural characterization of grain boundaries in materials with relatively simple crystal structures, mostly cubic systems. In this paper, a method for determining coincidence rotations in orthorhombic systems is given. This method is based on the vector-quaternion algorithm which is very close to the quadruple algorithm developed by Grimmer and used.

  2. 77 FR 70449 - Medical Device User Fee and Modernization Act; Notice to Public of Web Site Location of Fiscal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2012-11-26

    ...The Food and Drug Administration (FDA) is announcing the Web site location where the Agency will post two lists of guidance documents that the Center for Devices and Radiological Health (CDRH) is intending to publish in Fiscal Year (FY) 2013. In addition, FDA has established a docket where stakeholders may provide comments and/or propose draft language for those topics, suggest new or......

  3. 76 FR 61367 - Medical Device User Fee and Modernization Act; Notice to Public of Web Site Location of Fiscal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2011-10-04

    ...The Food and Drug Administration (FDA) is announcing the Web site location where the Agency will post a list of guidance documents the Center for Devices and Radiological Health (CDRH) is considering for development. In addition, FDA has established a docket where stakeholders may provide comments and/or draft language for those topics as well as suggestions for new or different...

  4. 75 FR 60761 - Medical Device User Fee and Modernization Act; Notice to Public of Web site Location of Fiscal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2010-10-01

    ...The Food and Drug Administration (FDA) is announcing the Web site location where it will post a list of guidance documents the Center for Devices and Radiological Health (CDRH) is considering for development. In addition, FDA has established a docket where stakeholders may provide comments and/or draft language for those topics as well as suggestions for new or different...

  5. 78 FR 21155 - Eastman Kodak Company, IPS-Dayton Location, Including On-site Leased Workers From Adecco, Dayton...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-04-09

    ... From the Federal Register Online via the Government Publishing Office DEPARTMENT OF LABOR Employment and Training Administration Eastman Kodak Company, IPS--Dayton Location, Including On-site Leased... August 1, 2012 by the Department of Labor on behalf of workers and former workers of Eastman...

  6. Long-term dependencies on selected GPS-SLR co-located sites

    NASA Astrophysics Data System (ADS)

    Bogusz, Janusz; Figurski, Mariusz; Klos, Anna; Schillak, Stanislaw; Szafranek, Karolina

    2014-05-01

    We have used XYZ coordinates in ITRF2008 obtained by GPS data processing in Bernese 5.0 and SLR in GEODYN-II from 20 globally distributed co-located sites. 10 of them are placed in Europe (10 GPS and 12 SLR at the same time), 2 in Australia (2 GPS and 3 SLR), 3 in Asia (3 GPS and 3 SLR), 1 in Africa (1 GPS and 1 SLR), 1 in South America (1 GPS and 1 SLR), and 3 in United States (3 GPS and 3 SLR). The threshold of 5 years of continuous observations was implemented. The longest time series are even 18 years long. At the pre-processing stage for removing outliers median absolute deviation (MAD) was applied as well as the sequential t-test algorithm for analysing regime shifts (STARS). Afterwards we have examined the annual signals in North-East-Up components by least squares estimation (LSE) and compared the obtained amplitudes and phase shifts (number of months between maximum of best-fitted annual sinusoid and the beginning of the year) for both types of observations. The amplitudes change from 1 to even 21 mm, while phase shifts are unevenly distributed over the seasons. No consistency (by means of region-dependencies as well as observation-dependencies) in the obtained results was obtained. It is very well recognised that annual signal in GPS-driven time series could be an artefact of several factors (e.g. draconitic year or mismodelling in short-periods). From the other side if correlated noise is present in the data, artificial oscillations can be generated in the low frequency band and can be taken by a mistake as true signals probably in both types of observations. Therefore we have applied wavelet decomposition (WD), which can be used to determine and model time series components with the modulated amplitude, but constant in phase signals. The frequency-determined components of time series at various decomposition levels enable selection of those that we are interested in, and we can remove them from further analysis. Each time series S(t) is divided into low

  7. Location of a permeant anion binding site in the cystic fibrosis transmembrane conductance regulator chloride channel pore.

    PubMed

    Rubaiy, Hussein N; Linsdell, Paul

    2015-05-01

    In the cystic fibrosis transmembrane conductance regulator (CFTR) chloride channel, lyotropic anions with high permeability also bind relatively tightly within the pore. However, the location of permeant anion binding sites, as well as their relationship to anion permeability, is not known. We have identified lysine residue K95 as a key determinant of permeant anion binding in the CFTR pore. Lyotropic anion binding affinity is related to the number of positively charged amino acids located in the inner vestibule of the pore. However, mutations that change the number of positive charges in this pore region have minimal effects on anion permeability. In contrast, a mutation at the narrow pore region alters permeability with minimal effects on anion binding. Our results suggest that a localized permeant anion binding site exists in the pore; however, anion binding to this site has little influence over anion permeability. Implications of this work for the mechanisms of anion recognition and permeability in CFTR are discussed. PMID:25673337

  8. Location analysis and strontium-90 concentrations in deer antlers on the Hanford Site

    SciTech Connect

    Tiller, B L; Eberhardt, L E; Poston, T M

    1995-05-01

    The primary objective of this study was to examine the levels of strontium-90 ({sup 90}Sr) in deer antlers collected from near previously active reactor sites and distant from the reactor sites along that portion of the Columbia River which borders the Hanford Site. A second objective was to analyze the movements and home-ranges of mule deer residing within these areas and determine to what extent this information contributes to the observed {sup 90}Sr concentrations. {sup 90}Sr is a long-lived radionuclide (29.1 year half life) produced by fission in irradiated fuel in plutonium production reactors on the Hanford Site. It is also a major component of atmospheric fallout from weapons testing. Concentrations of radionuclides found in the developed environment onsite do not pose a health concern to humans or various wildlife routinely monitored. However, elevated levels of radionuclides in found biota may indicate routes of exposure requiring attention.

  9. Locating high-affinity fatty acid-binding sites on albumin by x-ray crystallography and NMR spectroscopy

    PubMed Central

    Simard, J. R.; Zunszain, P. A.; Ha, C.-E.; Yang, J. S.; Bhagavan, N. V.; Petitpas, I.; Curry, S.; Hamilton, J. A.

    2005-01-01

    Human serum albumin (HSA) is a versatile transport protein for endogenous compounds and drugs. To evaluate physiologically relevant interactions between ligands for the protein, it is necessary to determine the locations and relative affinities of different ligands for their binding site(s). We present a site-specific investigation of the relative affinities of binding sites on HSA for fatty acids (FA), the primary physiological ligand for the protein. Titration of HSA with [13C]carboxyl-labeled FA was used initially to identify three NMR chemical shifts that are associated with high-affinity binding pockets on the protein. To correlate these peaks with FA-binding sites identified from the crystal structures of FA–HSA complexes, HSA mutants were engineered with substitutions of amino acids involved in coordination of the bound FA carboxyl. Titration of [13C]palmitate into solutions of HSA mutants for either FA site four (R410A/Y411A) or site five (K525A) within domain III of HSA each revealed loss of a specific NMR peak that was present in spectra of wild-type protein. Because these peaks are among the first three to be observed on titration of HSA with palmitate, sites four and five represent two of the three high-affinity long-chain FA-binding sites on HSA. These assignments were confirmed by titration of [13C]palmitate into recombinant domain III of HSA, which contains only sites four and five. These results establish a protocol for direct probing of the relative affinities of FA-binding sites, one that may be extended to examine competition between FA and other ligands for specific binding sites. PMID:16330771

  10. Locating high-affinity fatty acid-binding sites on albumin by x-ray crystallography and NMR spectroscopy.

    PubMed

    Simard, J R; Zunszain, P A; Ha, C-E; Yang, J S; Bhagavan, N V; Petitpas, I; Curry, S; Hamilton, J A

    2005-12-13

    Human serum albumin (HSA) is a versatile transport protein for endogenous compounds and drugs. To evaluate physiologically relevant interactions between ligands for the protein, it is necessary to determine the locations and relative affinities of different ligands for their binding site(s). We present a site-specific investigation of the relative affinities of binding sites on HSA for fatty acids (FA), the primary physiological ligand for the protein. Titration of HSA with [(13)C]carboxyl-labeled FA was used initially to identify three NMR chemical shifts that are associated with high-affinity binding pockets on the protein. To correlate these peaks with FA-binding sites identified from the crystal structures of FA-HSA complexes, HSA mutants were engineered with substitutions of amino acids involved in coordination of the bound FA carboxyl. Titration of [(13)C]palmitate into solutions of HSA mutants for either FA site four (R410A/Y411A) or site five (K525A) within domain III of HSA each revealed loss of a specific NMR peak that was present in spectra of wild-type protein. Because these peaks are among the first three to be observed on titration of HSA with palmitate, sites four and five represent two of the three high-affinity long-chain FA-binding sites on HSA. These assignments were confirmed by titration of [(13)C]palmitate into recombinant domain III of HSA, which contains only sites four and five. These results establish a protocol for direct probing of the relative affinities of FA-binding sites, one that may be extended to examine competition between FA and other ligands for specific binding sites. PMID:16330771

  11. Impact sites representing potential bruising locations associated with rearward falls in children.

    PubMed

    Dsouza, Raymond; Bertocci, Gina

    2016-04-01

    Children presenting multiple unexplained bruises can be an early sign of physical abuse. Bruising locations on the body can be an effective indicator of abusive versus accidental trauma. Additionally, childhood falls are often used as falsely reported events in child abuse, however, characterization of potential bruising locations associated with these falls does not exist. In our study we used a 12-month old pediatric anthropomorphic test device (ATD) adapted with a custom developed force sensing skin to predict potential bruising locations during rearward falls from standing. The surrogate bruising detection system measured and displayed recorded force data on a computerized body image mapping system when sensors were activated. Simulated rearward fall experiments were performed onto two different impact surfaces (padded carpet and linoleum tile over concrete) with two different initial positions (standing upright and posteriorly inclined) so that the ATD would fall rearward upon release. Findings indicated impact locations, and thus the potential for bruising in the posterior plane primarily within the occipital head and posterior torso regions. PMID:26921816

  12. DIOXIN TRANSPORT FROM CONTAMINATED SITES TO EXPOSURE LOCATIONS: A METHODOLOGY FOR CALCULATING CONVERSION FACTORS

    EPA Science Inventory

    Procedures have been developed by the US EPA for estimating the risk associated with exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (dioxin). Concentrations of dioxin at the contaminant source are usually known, but exposure may occur at locations away from the source where conc...

  13. Tables of co-located geothermal-resource sites and BLM Wilderness Study Areas

    SciTech Connect

    Foley, D.; Dorscher, M.

    1982-11-01

    Matched pairs of known geothermal wells and springs with BLM proposed Wilderness Study Areas (WSAs) were identified by inspection of WSA and Geothermal resource maps for the states of Arizona, California, Colorado, Idaho, Montana, Nevada, New Mexico, Oregon, Utah, Washington and Wyoming. A total of 3952 matches, for geothermal sites within 25 miles of a WSA, were identified. Of these, only 71 (1.8%) of the geothermal sites are within one mile of a WSA, and only an additional 100 (2.5%) are within one to three miles. Approximately three-fourths of the matches are at distances greater than ten miles. Only 12 of the geothermal sites within one mile of a WSA have surface temperatures reported above 50/sup 0/C. It thus appears that the geothermal potential of WSAs overall is minimal, but that evaluation of geothermal resources should be considered in more detail for some areas prior to their designation as Wilderness.

  14. Modeling a tracer test at the Grimsel Test Site (GTS) using a lattice Boltzmann method and transmissivity field

    NASA Astrophysics Data System (ADS)

    Kim, J. W.; Lanyon, G. W.; Baik, M. H.; Blechschmidt, I.

    2015-12-01

    A series of tracer tests have been conducted in the Migration (MI) Shear Zone at the Grimsel Test Site (GTS) for the Colloid Formation and Migration Project (CFM). As a part of the series, a dipole test (Tracer Test Run 13-05) using radionuclides, colloids and conservative tracers was performed to determine the breakthrough between CRR99.002-i2 and BOMI87.010-i2. To date, the breakthrough data of only the conservative dye tracer (Amino-G acid) are available. In the preceding project, the Colloid and Radionuclide Retardation Project (CRR), a transmissivity field for the MI shear zone was obtained by the geostatistical inverse modeling approach. In this study, the breakthrough of the tracer was computed by a gray lattice Boltzmann method (LBM). The transmissivity field with finite elements grid was transformed to the effective fracture aperture or flow porosity according to the cubic law, and the grid was uniformalized by the interpolation. The uniform mesh of the effective aperture was utilized as the model domain of the gray LBM. In the gray LBM, the heterogeneity of the aperture was dealt with a partial-bounceback scheme. The profiles of hydraulic heads monitored at the boreholes nearby were used as the reference values in the calculation of the pressure distribution in the model domain. The modeling results could reveal a dominant pathway of tracers in the dipole test. The developed model can be utilized in the calculation of the reactive transports of radionuclides and colloids by coupling with a geochemical model, such as Phreeqc, the Geochemist's Workbench, etc.

  15. Conversion of Hanford site well locations to Washington coordinate system of 1983, South Zone 1991 (WCS83S)

    SciTech Connect

    Burnett, R.A.; Tzemos, S.; Dietz, L.A.

    1993-12-01

    Past construction and survey practices have resulted in the use of multiple local coordinate systems for measuring and reporting the horizontal position of wells and other facilities and locations on the Hanford Site. This report describes the development of a coordinate transformation process and algorithm and its application to the conversion of the horizontal coordinates of Hanford site wells from the various local coordinate systems and datums to a single standard coordinate system, the Washington Coordinate system of 1983, South Zone 1991 (WCS83S). The coordinate transformation algorithm, implemented as a computer program called CTRANS, uses standard two-dimensional translation, rotation, and scaling transformation equations and can be applied to any set of horizontal point locations. For each point to be transformed, the coefficients of the transformation equations are calculated locally, using the coordinates of the three nearest registration points (points with known locations in both coordinate systems). The report contains a discussion of efforts to verify and validate both the software and the well location data, a description of the methods used to estimate transformation and registration point accuracy, instructions for using the computer program, and a summary of the Hanford well conversion results for each local coordinate system and datum. Also included are the results of using recent U.S. Army Corps of Engineers survey data to obtain estimated measures of location errors in wells for which the local coordinate data source is undocumented, unverified, and therefore of unknown accuracy.

  16. Relationship Between PM2.5 Collected at Residential Outdoor Locations and a Central Site

    EPA Science Inventory

    Regression models are developed to describe the relationship between ambient PM2.5 (particulate matter [PM] ≤ 2.5 μm in aerodynamic diameter) mass concentrations measured at a central-site monitor with those at residential outdoor monitors. Understanding the...

  17. Nuclear waste repository siting and locational conflict analysis: A contextual approach

    SciTech Connect

    Murauskas, G.T.

    1989-01-01

    This study develops and evaluates an alternative framework that is based on contextual variables. The premise is that differences in attitudes and perceptions regarding the local siting of nuclear wastes and differences in attitudes regarding siting decision-making procedures are influenced by local political, economic, and cultural variables. This framework articulates the nature of conflict in terms of the incongruence between the use-value individuals ascribe to their present situation and the anticipated exchange-value individuals associate with the local siting of a nuclear waste repository. In order to evaluate this conceptual framework a survey was conducted of residents in four communities representing distinct societal contexts: Richton, Mississippi; Peterborough, New Hampshire; Richland, Washington; and Antigo/Waupaca, Wisconsin. Data analyses indicate substantial differences in economic expectations associated with the local siting of a high-level nuclear waste repository and in perception regarding the impacts such a repository might have on the environment, local agriculture, personal health and safety, and the quality of life.

  18. 14 CFR 420.19 - Launch site location review-general.

    Code of Federal Regulations, 2010 CFR

    2010-01-01

    ... site, at least one type of expendable or reusable launch vehicle can be flown from the launch point... have more than one type of launch vehicle flown from a launch point, the applicant shall demonstrate that each type of expendable or reusable launch vehicle planned to be flown from the launch point...

  19. 14 CFR 420.19 - Launch site location review-general.

    Code of Federal Regulations, 2011 CFR

    2011-01-01

    ... site, at least one type of expendable or reusable launch vehicle can be flown from the launch point... have more than one type of launch vehicle flown from a launch point, the applicant shall demonstrate that each type of expendable or reusable launch vehicle planned to be flown from the launch point...

  20. Location of the unique integration site on an Escherichia coli chromosome by bacteriophage lambda DNA in vivo.

    PubMed

    Tal, Asaf; Arbel-Goren, Rinat; Costantino, Nina; Court, Donald L; Stavans, Joel

    2014-05-20

    The search for specific sequences on long genomes is a key process in many biological contexts. How can specific target sequences be located with high efficiency, within physiologically relevant times? We addressed this question for viral integration, a fundamental mechanism of horizontal gene transfer driving prokaryotic evolution, using the infection of Escherichia coli bacteria with bacteriophage λ and following the establishment of a lysogenic state. Following the targeting process in individual live E. coli cells in real time revealed that λ DNA remains confined near the entry point of a cell following infection. The encounter between the 15-bp-long target sequence on the chromosome and the recombination site on the viral genome is facilitated by the directed motion of bacterial DNA generated during chromosome replication, in conjunction with constrained diffusion of phage DNA. Moving the native bacterial integration site to different locations on the genome and measuring the integration frequency in these strains reveals that the frequencies of the native site and a site symmetric to it relative to the origin are similar, whereas both are significantly higher than when the integration site is moved near the terminus, consistent with the replication-driven mechanism we propose. This novel search mechanism is yet another example of the exquisite coevolution of λ with its host. PMID:24799672

  1. Location selection criteria for a second data center or off-site storage of materials.

    PubMed

    Cochran, Mitchell; Witman, Paul

    2013-01-01

    As organizations develop secondary data centers, it is critical that they be placed in locations that serve the organization yet do not have a shared risk with the primary data center. The organization needs to consider factors or guidelines which mitigate potential issues that could affect both the primary and secondary data center. It is impossible to eliminate all risk to a single data center but an organization needs to ensure that at least one data center remains operable. The article will propose that data centers be located 50 km or approximately 30 miles apart. The proposal is supported by evaluating earthquake intensity maps that will show that earthquakes damage drops to relatively safe levels after the 30 miles from the epicenter. The article will show that other environmental factors such as power, floods, fire, transportation, fire, and soil are also mitigated by a 30-mile separation guideline. PMID:24180066

  2. Site Fidelity and Individual Variation in Winter Location in Partially Migratory European Shags

    PubMed Central

    Grist, Hannah; Daunt, Francis; Wanless, Sarah; Nelson, Emily J.; Harris, Mike P.; Newell, Mark; Burthe, Sarah; Reid, Jane M.

    2014-01-01

    In partially migratory populations, individuals from a single breeding area experience a range of environments during the non-breeding season. If individuals show high within- and among- year fidelity to specific locations, any annual environmental effect on individual life histories could be reinforced, causing substantial demographic heterogeneity. Quantifying within- and among- individual variation and repeatability in non-breeding season location is therefore key to predicting broad-scale environmental impacts on the dynamics of partially migratory populations. We used field resightings of colour-ringed adult European shags known to have bred on the Isle of May, Scotland, to quantify individual variation and repeatability in winter location within and among three consecutive winters. In total, 3797 resightings of 882 individuals were recorded over 622 km of coastline, including the Isle of May. These individuals comprised over 50% of the known breeding population, and encompassed representative distributions of ages and sexes. The distances from the Isle of May at which individuals were resighted during winter varied substantially, up to 486 km and 136 km north and south respectively and including the breeding colony on the Isle of May. However, resighting distances were highly repeatable within individuals; within- and among-winter repeatabilities were >0.72 and >0.59 respectively across the full September-March observation period, and >0.95 and >0.79 respectively across more restricted mid-winter periods. Repeatability did not differ significantly between males and females or among different age classes, either within or among winters. These data demonstrate that the focal shag population is partially migratory, and moreover that individuals show highly repeatable variation in winter location and hence migration strategy across consecutive winters. Such high among-individual variation and within-individual repeatability, both within and among winters, could

  3. Microwave detection system for locating hemorrhage sites within the cranium and other regions

    NASA Astrophysics Data System (ADS)

    Riechers, Ronald G., Sr.; Pasala, Krishna M.; Ling, Geoffrey S. F.

    1998-05-01

    A novel method for location and characterization of discontinuities in biological system is presented. The method uses electromagnetic waves in the microwave and RF region and a modified algorithm previously used for the estimation of the angle of arrival of radar signals. Results are presented for the case of a skull section backed by porcine brain and the same section backed by a layer of blood backed by porcine brain.

  4. Co-doping of (Bi0.5Na0.5)TiO3: secondary phase formation and lattice site preference of Co

    NASA Astrophysics Data System (ADS)

    Schmitt, V.; Staab, T. E. M.

    2012-11-01

    Bismuth sodium titanate (Bi0.5Na0.5)TiO3 (BNT) is considered to be one of the most promising lead-free alternatives to piezoelectric lead zirconate titanate (PZT). However, the effect of dopants on the material has so far received little attention from an atomic point of view. In this study we investigated the effects of cobalt-doping on the formation of additional phases and determined the preferred lattice site of cobalt in BNT. The latter was achieved by comparing the measured x-ray absorption near-edge structure (XANES) spectra to numerically calculated spectra of cobalt on various lattice sites in BNT. (Bi0.5Na0.5)TiO3 + x mol% Co (x = 0.0, 0.5, 1.0, 2.6) was synthesized via solid state reaction. As revealed by SEM backscattering images, a secondary phase formed in all doped specimens. Using both XRD and SEM-EDX, it was identified as Co2TiO4 for dopant levels >0.5 mol%. In addition, a certain amount of cobalt was incorporated into BNT, as shown by electron probe microanalysis. This amount increased with increasing dopant levels, suggesting that an equilibrium forms together with the secondary phase. The XANES experiments revealed that cobalt occupies the octahedral B-site in the BNT perovskite lattice, substituting Ti and promoting the formation of oxygen vacancies in the material.

  5. Location of the Bombyx mori aminopeptidase N type 1 binding site on Bacillus thuringiensis Cry1Aa toxin.

    PubMed

    Atsumi, Shogo; Mizuno, Eri; Hara, Hirotaka; Nakanishi, Kazuko; Kitami, Madoka; Miura, Nami; Tabunoki, Hiroko; Watanabe, Ayako; Sato, Ryoichi

    2005-07-01

    We analyzed the binding site on Cry1Aa toxin for the Cry1Aa receptor in Bombyx mori, 115-kDa aminopeptidase N type 1 (BmAPN1) (K. Nakanishi, K. Yaoi, Y. Nagino, H. Hara, M. Kitami, S. Atsumi, N. Miura, and R. Sato, FEBS Lett. 519:215-220, 2002), by using monoclonal antibodies (MAbs) that block binding between the binding site and the receptor. First, we produced a series of MAbs against Cry1Aa and obtained two MAbs, MAbs 2C2 and 1B10, that were capable of blocking the binding between Cry1Aa and BmAPN1 (blocking MAbs). The epitope of the Fab fragments of MAb 2C2 overlapped the BmAPN1 binding site, whereas the epitope of the Fab fragments of MAb 1B10 did not overlap but was located close to the binding site. Using three approaches for epitope mapping, we identified two candidate epitopes for the blocking MAbs on Cry1Aa. We constructed two Cry1Aa toxin mutants by substituting a cysteine on the toxin surface at each of the two candidate epitopes, and the small blocking molecule N-(9-acridinyl)maleimide (NAM) was introduced at each cysteine substitution to determine the true epitope. The Cry1Aa mutant with NAM bound to Cys582 did not bind either of the two blocking MAbs, suggesting that the true epitope for each of the blocking MAbs was located at the site containing Val582, which also consisted of 508STLRVN513 and 582VFTLSAHV589. These results indicated that the BmAPN1 binding site overlapped part of the region blocked by MAb 2C2 that was close to but excluded the actual epitope of MAb 2C2 on domain III of Cry1Aa toxin. We also discuss another area on Cry1Aa toxin as a new candidate site for BmAPN1 binding. PMID:16000811

  6. Location of the Bombyx mori Aminopeptidase N Type 1 Binding Site on Bacillus thuringiensis Cry1Aa Toxin

    PubMed Central

    Atsumi, Shogo; Mizuno, Eri; Hara, Hirotaka; Nakanishi, Kazuko; Kitami, Madoka; Miura, Nami; Tabunoki, Hiroko; Watanabe, Ayako; Sato, Ryoichi

    2005-01-01

    We analyzed the binding site on Cry1Aa toxin for the Cry1Aa receptor in Bombyx mori, 115-kDa aminopeptidase N type 1 (BmAPN1) (K. Nakanishi, K. Yaoi, Y. Nagino, H. Hara, M. Kitami, S. Atsumi, N. Miura, and R. Sato, FEBS Lett. 519:215-220, 2002), by using monoclonal antibodies (MAbs) that block binding between the binding site and the receptor. First, we produced a series of MAbs against Cry1Aa and obtained two MAbs, MAbs 2C2 and 1B10, that were capable of blocking the binding between Cry1Aa and BmAPN1 (blocking MAbs). The epitope of the Fab fragments of MAb 2C2 overlapped the BmAPN1 binding site, whereas the epitope of the Fab fragments of MAb 1B10 did not overlap but was located close to the binding site. Using three approaches for epitope mapping, we identified two candidate epitopes for the blocking MAbs on Cry1Aa. We constructed two Cry1Aa toxin mutants by substituting a cysteine on the toxin surface at each of the two candidate epitopes, and the small blocking molecule N-(9-acridinyl)maleimide (NAM) was introduced at each cysteine substitution to determine the true epitope. The Cry1Aa mutant with NAM bound to Cys582 did not bind either of the two blocking MAbs, suggesting that the true epitope for each of the blocking MAbs was located at the site containing Val582, which also consisted of 508STLRVN513 and 582VFTLSAHV589. These results indicated that the BmAPN1 binding site overlapped part of the region blocked by MAb 2C2 that was close to but excluded the actual epitope of MAb 2C2 on domain III of Cry1Aa toxin. We also discuss another area on Cry1Aa toxin as a new candidate site for BmAPN1 binding. PMID:16000811

  7. 78 FR 66746 - Medical Device User Fee and Modernization Act; Notice to Public of Web Site Location of Fiscal...

    Federal Register 2010, 2011, 2012, 2013, 2014

    2013-11-06

    ...The Food and Drug Administration (FDA or the Agency) is announcing the Web site location where the Agency will post two lists of guidance documents the Center for Devices and Radiological Health (CDRH) is intending to publish in Fiscal Year (FY) 2014. In addition, FDA has established a docket where stakeholders may provide comments and/or propose draft language for those topics, suggest new or......

  8. Factors influencing the heavy metal bioaccessibility in soils were site dependent from different geographical locations.

    PubMed

    Zhu, Xiaodong; Yang, Fen; Wei, Chaoyang

    2015-09-01

    A soil survey was conducted in urban areas from five sites, including Beijing, Baotou, Datong, Fuyang, and Xiantao in China. The objective was to explore the most significant factors that may impact the bioaccessibility of heavy metals (Bio-HMs), including As, Cr, Cu, Pb, and Zn, in soils. Twenty to 30 composite soil samples were collected at each site. The various soil properties, including pH, particle size, Fe/Mn, and organic matter contents, were analyzed. The chemical operated forms of HMs in soils were measured by the Bureau of Reference (BCR) sequential extraction scheme, while the Bio-HMs were determined by the simple bioaccessibility extraction test (SBET) procedure. The concentrations of total heavy metals (T-HMs) in soils from different sites (cities) were in the range as As (5.69-9.86), Cr (77.42-230.20), Cu (15.68-36.54), Pb (14.12-58.93), and Zn (38.66-183.46) mg/kg. Cu and Pb had higher relative bioaccessibilities (48-70%) than those of As and Cr (6-15%), indicating higher health risks of the former than the latter two HMs. The Bio-HMs for various HMs were comparable to the first two or three combined BCR extracted fractions, with an exception of Cu, whose Bio-HMs were larger than the combined three BCR fractions, indicating that Cu was highly accessible in soils as compared with other HMs. Factor analysis showed that all variables, including soil property parameters and BCR extracted fractions, could be represented by three common factors extracted with higher than 0.5 loadings and ∼80% cumulative contribution to the total variance. Among the three common factors, factor 1, containing mainly pH, texture, and Fe/Mn variables, and factor 3, containing mainly organic matter variable, could be attributed to geographical regions, while factor 2, containing mainly BCR extracted fractions, could be ascribed to relative bioaccessibility of HMs (R-Bio-HMs). Interactive mapping of the main factors and cluster analysis were consistent, which supported the

  9. Early prediction of eruption site using lightning location data: An operational real-time system in Iceland

    NASA Astrophysics Data System (ADS)

    Arason, Þórður; Bjornsson, Halldór; Nína Petersen, Guðrún

    2013-04-01

    Eruption of subglacial volcanoes may lead to catastrophic floods and thus early determination of the exact eruption site may be critical to civil protection evacuation plans. A system is being developed that automatically monitors and analyses volcanic lightning in Iceland. The system predicts the eruption site location from mean lightning locations, taking into account upper level wind. In estimating mean lightning locations, outliers are automatically omitted. A simple wind correction is performed based on the vector wind at the 500 hPa pressure level in the latest radiosonde from Keflavík airport. The system automatically creates a web page with maps and tables showing individual lightning locations and mean locations with and without wind corrections along with estimates of uncetainty. A dormant automatic monitoring system, waiting for a rare event, potentially for several years, is quite susceptible to degeneration during the waiting period, e.g. due to computer or other IT-system upgrades. However, ordinary weather thunderstorms in Iceland should initiate special monitoring and automatic analysis of this system in the same fashion as during a volcanic eruption. Such ordinary weather thunderstorm events will be used to observe anomalies and malfunctions in the system. The essential elements of this system will be described. An example is presented of how the system would have worked during the first hours of the Grímsvötn 2011 eruption. In that case the exact eruption site, within the Grímsvötn caldera, was first known about 15 hours into the eruption.

  10. The effect of accelerometer location on the classification of single-site forearm mechanomyograms

    PubMed Central

    2010-01-01

    Background Recently, pattern recognition methods have been deployed in the classification of multiple activation states from mechanomyogram (MMG) signals for the purpose of controlling switching interfaces. Given the propagative properties of MMG signals, it has been suggested that MMG classification should be robust to changes in sensor placement. Nonetheless, this purported robustness remains speculative to date. This study sought to quantify the change in classification accuracy, if any, when a classifier trained with MMG signals from the muscle belly, is subsequently tested with MMG signals from a nearby location. Methods An arrangement of 5 accelerometers was attached to the flexor carpi radialis muscle of 12 able-bodied participants; a reference accelerometer was located over the muscle belly, two peripheral accelerometers were positioned along the muscle's transverse axis and two more were aligned to the muscle's longitudinal axis. Participants performed three classes of muscle activity: wrist flexion, wrist extension and semi-pronation. A collection of time, frequency and time-frequency features were considered and reduced by genetic feature selection. The classifier, trained using features from the reference accelerometer, was tested with signals from the longitudinally and transversally displaced accelerometers. Results Classification degradation due to accelerometer displacement was significant for all participants, and showed no consistent trend with the direction of displacement. Further, the displaced accelerometer signals showed task-dependent de-correlations with respect to the reference accelerometer. Conclusions These results indicate that MMG signal features vary with spatial location and that accelerometer displacements of only 1-2 cm cause sufficient feature drift to significantly diminish classification accuracy. This finding emphasizes the importance of consistent sensor placement between MMG classifier training and deployment for accurate

  11. Real-Time Safety Risk Assessment Based on a Real-Time Location System for Hydropower Construction Sites

    PubMed Central

    Fan, Qixiang; Qiang, Maoshan

    2014-01-01

    The concern for workers' safety in construction industry is reflected in many studies focusing on static safety risk identification and assessment. However, studies on real-time safety risk assessment aimed at reducing uncertainty and supporting quick response are rare. A method for real-time safety risk assessment (RTSRA) to implement a dynamic evaluation of worker safety states on construction site has been proposed in this paper. The method provides construction managers who are in charge of safety with more abundant information to reduce the uncertainty of the site. A quantitative calculation formula, integrating the influence of static and dynamic hazards and that of safety supervisors, is established to link the safety risk of workers with the locations of on-site assets. By employing the hidden Markov model (HMM), the RTSRA provides a mechanism for processing location data provided by the real-time location system (RTLS) and analyzing the probability distributions of different states in terms of false positives and negatives. Simulation analysis demonstrated the logic of the proposed method and how it works. Application case shows that the proposed RTSRA is both feasible and effective in managing construction project safety concerns. PMID:25114958

  12. Real-time safety risk assessment based on a real-time location system for hydropower construction sites.

    PubMed

    Jiang, Hanchen; Lin, Peng; Fan, Qixiang; Qiang, Maoshan

    2014-01-01

    The concern for workers' safety in construction industry is reflected in many studies focusing on static safety risk identification and assessment. However, studies on real-time safety risk assessment aimed at reducing uncertainty and supporting quick response are rare. A method for real-time safety risk assessment (RTSRA) to implement a dynamic evaluation of worker safety states on construction site has been proposed in this paper. The method provides construction managers who are in charge of safety with more abundant information to reduce the uncertainty of the site. A quantitative calculation formula, integrating the influence of static and dynamic hazards and that of safety supervisors, is established to link the safety risk of workers with the locations of on-site assets. By employing the hidden Markov model (HMM), the RTSRA provides a mechanism for processing location data provided by the real-time location system (RTLS) and analyzing the probability distributions of different states in terms of false positives and negatives. Simulation analysis demonstrated the logic of the proposed method and how it works. Application case shows that the proposed RTSRA is both feasible and effective in managing construction project safety concerns. PMID:25114958

  13. Integrating smart-phone based momentary location tracking with fixed site air quality monitoring for personal exposure assessment.

    PubMed

    Su, Jason G; Jerrett, Michael; Meng, Ying-Ying; Pickett, Melissa; Ritz, Beate

    2015-02-15

    Epidemiological studies investigating relationships between environmental exposures from air pollution and health typically use residential addresses as a single point for exposure, while environmental exposures in transit, at work, school or other locations are largely ignored. Personal exposure monitors measure individuals' exposures over time; however, current personal monitors are intrusive and cannot be operated at a large scale over an extended period of time (e.g., for a continuous three months) and can be very costly. In addition, spatial locations typically cannot be identified when only personal monitors are used. In this paper, we piloted a study that applied momentary location tracking services supplied by smart phones to identify an individual's location in space-time for three consecutive months (April 28 to July 28, 2013) using available Wi-Fi networks. Individual exposures in space-time to the traffic-related pollutants Nitrogen Oxides (NOX) were estimated by superimposing an annual mean NOX concentration surface modeled using the Land Use Regression (LUR) modeling technique. Individual's exposures were assigned to stationary (including home, work and other stationary locations) and in-transit (including commute and other travel) locations. For the individual, whose home/work addresses were known and the commute route was fixed, it was found that 95.3% of the time, the individual could be accurately identified in space-time. The ambient concentration estimated at the home location was 21.01 ppb. When indoor/outdoor infiltration, indoor sources of air pollution and time spent outdoors were taken into consideration, the individual's cumulative exposures were 28.59 ppb and 96.49 ppb, assuming a respective indoor/outdoor ratio of 1.33 and 5.00. Integrating momentary location tracking services with fixed-site field monitoring, plus indoor-outdoor air exchange calibration, makes exposure assessment of a very large population over an extended time period

  14. Locations of the three primary binding sites for long-chain fatty acids on bovine serum albumin

    SciTech Connect

    Hamilton, J.A.; Era, S.; Bhamidipati, S.P. ); Reed, R.G. )

    1991-03-15

    Binding of {sup 13}C-enriched oleic acid to bovine serum albumin and to three large proteolytic fragments of albumin - two complementary fragments corresponding to the two halved of albumin and one fragment corresponding to the carboxyl-terminal domain - yielded unique patterns of NMR resonances (chemical shifts and relative intensities) that were used to identify the locations of binding of the first 5 mol of oleic acid to the multidomain albumin molecule. The first 3 mol of oleic acid added to intact albumin generated three distinct NMR resonances as a result of simultaneous binding of oleic acid to three heterogeneous sites (primary sites). This distribution suggests albumin to be a less symmetrical binding molecule than theoretical models predict. This work also demonstrates the power of NMR for the study of microenvironments of individual fatty acid binding sites in specific domain.

  15. Chromosomal location of 18S and 5S rDNA sites in Triportheus fish species (Characiformes, Characidae)

    PubMed Central

    2009-01-01

    The location of 18S and 5S rDNA sites was determined in eight species and populations of the fish genus Triportheus by using fluorescent in situ hybridization (FISH). The males and females of all species had 2n = 52 chromosomes and a ZZ/ZW sex chromosome system. A single 18S rDNA site that was roughly equivalent to an Ag-NOR was detected on the short arms of a submetacentric pair in nearly all species, and up to two additional sites were also observed in some species. In addition, another 18S rDNA cluster was identified in a distal region on the long arms of the W chromosome; this finding corroborated previous evidence that this cluster would be a shared feature amongst Triportheus species. In T. angulatus, a heterozygotic paracentric inversion involving the short arms of one homolog of a metacentric pair was associated with NORs. The 5S rDNA sites were located on the short arms of a single submetacentric chromosomal pair, close to the centromeres, except in T. auritus, which had up to ten 5S rDNA sites. The 18S and 5S rDNA sites were co-localized and adjacent on the short arms of a chromosomal pair in two populations of T. nematurus. Although all Triportheus species have a similar karyotypic macrostructure, the results of this work show that in some species ribosomal genes may serve as species-specific markers when used in conjunction with other putatively synapomorphic features. PMID:21637644

  16. A Method for Place Name Display Considering User Locating Habits in Map Sites

    NASA Astrophysics Data System (ADS)

    Liu, X. C.; Li, X.; Wang, L.; Wang, P.

    2013-11-01

    The traditional researches for cartographic lettering and display focus on conflict among labels and overlap between labels and features. But these two issues are not significant in web maps. It is worthwhile to concern about how to improve labels' readability considering user locating habits for enhancing user experience. This paper has established a new method for place name display called "the gravitational field". This method is appropriate for the display of dotted place names from the national level (approximately 1:20 million) to city level (approximately 1:250 thousand) in web maps. We have conducted a usability test which used all nationwide provincial capitals, autonomous regions, municipalities, prefecture-level cities, municipal districts, countries and part of the townships dotted names. The results show that this rule improves web map's legibility, and can significantly enhance the user experience.

  17. Comparison of Magnetospheric Multiscale ion jet signatures with predicted reconnection site locations at the magnetopause

    NASA Astrophysics Data System (ADS)

    Petrinec, S. M.; Burch, J. L.; Fuselier, S. A.; Gomez, R. G.; Lewis, W.; Trattner, K. J.; Ergun, R.; Mauk, B.; Pollock, C. J.; Schiff, C.; Strangeway, R. J.; Russell, C. T.; Phan, T.-D.; Young, D.

    2016-06-01

    Magnetic reconnection at the Earth's magnetopause is the primary process by which solar wind plasma and energy gains access to the magnetosphere. One indication that magnetic reconnection is occurring is the observation of accelerated plasma as a jet tangential to the magnetopause. The direction of ion jets along the magnetopause surface as observed by the Fast Plasma Instrument (FPI) and the Hot Plasma Composition Analyzer (HPCA) instrument on board the recently launched Magnetospheric Multiscale (MMS) set of spacecraft is examined. For those cases where ion jets are clearly discerned, the direction of origin compares well statistically with the predicted location of magnetic reconnection using convected solar wind observations in conjunction with the Maximum Magnetic Shear model.

  18. Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field

    NASA Astrophysics Data System (ADS)

    Shore, Joel D.; Thurston, George M.

    2015-12-01

    We report a charge-patterning phase transition on two-dimensional square lattices of titratable sites, here regarded as protonation sites, placed in a low-dielectric medium just below the planar interface between this medium and a salt solution. We calculate the work-of-charging matrix of the lattice with use of a linear Debye-Hückel model, as input to a grand-canonical partition function for the distribution of occupancy patterns. For a large range of parameter values, this model exhibits an approximate inverse cubic power-law decrease of the voltage produced by an individual charge, as a function of its in-lattice separation from neighboring titratable sites. Thus, the charge coupling voltage biases the local probabilities of proton binding as a function of the occupancy of sites for many neighbors beyond the nearest ones. We find that even in the presence of these longer-range interactions, the site couplings give rise to a phase transition in which the site occupancies exhibit an alternating, checkerboard pattern that is an analog of antiferromagnetic ordering. The overall strength W of this canonical charge coupling voltage, per unit charge, is a function of the Debye length, the charge depth, the Bjerrum length, and the dielectric coefficients of the medium and the solvent. The alternating occupancy transition occurs above a curve of thermodynamic critical points in the (p H-p K ,W ) plane, the curve representing a charge-regulation analog of variation of the Néel temperature of an Ising antiferromagnet as a function of an applied, uniform magnetic field. The analog of a uniform magnetic field in the antiferromagnet problem is a combination of p H-p K and W , and 1 /W is the analog of the temperature in the antiferromagnet problem. We use Monte Carlo simulations to study the occupancy patterns of the titratable sites, including interactions out to the 37th nearest-neighbor category (a distance of √{74 } lattice constants), first validating simulations

  19. Charge-regulation phase transition on surface lattices of titratable sites adjacent to electrolyte solutions: An analog of the Ising antiferromagnet in a magnetic field.

    PubMed

    Shore, Joel D; Thurston, George M

    2015-12-01

    We report a charge-patterning phase transition on two-dimensional square lattices of titratable sites, here regarded as protonation sites, placed in a low-dielectric medium just below the planar interface between this medium and a salt solution. We calculate the work-of-charging matrix of the lattice with use of a linear Debye-Hückel model, as input to a grand-canonical partition function for the distribution of occupancy patterns. For a large range of parameter values, this model exhibits an approximate inverse cubic power-law decrease of the voltage produced by an individual charge, as a function of its in-lattice separation from neighboring titratable sites. Thus, the charge coupling voltage biases the local probabilities of proton binding as a function of the occupancy of sites for many neighbors beyond the nearest ones. We find that even in the presence of these longer-range interactions, the site couplings give rise to a phase transition in which the site occupancies exhibit an alternating, checkerboard pattern that is an analog of antiferromagnetic ordering. The overall strength W of this canonical charge coupling voltage, per unit charge, is a function of the Debye length, the charge depth, the Bjerrum length, and the dielectric coefficients of the medium and the solvent. The alternating occupancy transition occurs above a curve of thermodynamic critical points in the (pH-pK,W) plane, the curve representing a charge-regulation analog of variation of the Néel temperature of an Ising antiferromagnet as a function of an applied, uniform magnetic field. The analog of a uniform magnetic field in the antiferromagnet problem is a combination of pH-pK and W, and 1/W is the analog of the temperature in the antiferromagnet problem. We use Monte Carlo simulations to study the occupancy patterns of the titratable sites, including interactions out to the 37th nearest-neighbor category (a distance of √74 lattice constants), first validating simulations through

  20. Oligosaccharyltransferase directly binds to ribosome at a location near the translocon-binding site

    SciTech Connect

    Harada, Y.; Li, H.; Li, Hua; Lennarz, W. J.

    2009-04-28

    Oligosaccharyltransferase (OT) transfers high mannose-type glycans to the nascent polypeptides that are translated by the membrane-bound ribosome and translocated into the lumen of the endoplasmic reticulum through the Sec61 translocon complex. In this article, we show that purified ribosomes and OT can form a binary complex with a stoichiometry of {approx}1 to 1 in the presence of detergent. We present evidence that OT may bind to the large ribosomal subunit near the site where nascent polypeptides exit. We further show that OT and the Sec61 complex can simultaneously bind to ribosomes in vitro. Based on existing data and our findings, we propose that cotranslational translocation and N-glycosylation of nascent polypeptides are mediated by a ternary supramolecular complex consisting of OT, the Sec61 complex, and ribosomes.

  1. Surface wave site characterization at 27 locations near Boston, Massachusetts, including 2 strong-motion stations

    USGS Publications Warehouse

    Thompson, Eric M.; Carkin, Bradley A.; Baise, Laurie G.; Kayen, Robert E.

    2014-01-01

    The geotechnical properties of the soils in and around Boston, Massachusetts, have been extensively studied. This is partly due to the importance of the Boston Blue Clay and the extent of landfill in the Boston area. Although New England is not a region that is typically associated with seismic hazards, there have been several historical earthquakes that have caused significant ground shaking (for example, see Street and Lacroix, 1979; Ebel, 1996; Ebel, 2006). The possibility of strong ground shaking, along with heightened vulnerability from unreinforced masonry buildings, motivates further investigation of seismic hazards throughout New England. Important studies that are pertinent to seismic hazards in New England include source-parameter studies (Somerville and others, 1987; Boore and others, 2010), wave-propagation studies (Frankel, 1991; Viegas and others, 2010), empirical ground-motion prediction equations (GMPE) for computing ground-motion intensity (Tavakoli and Pezeshk, 2005; Atkinson and Boore, 2006), site-response studies (Hayles and others, 2001; Ebel and Kim, 2006), and liquefaction studies (Brankman and Baise, 2008). The shear-wave velocity (VS) profiles collected for this report are pertinent to the GMPE, site response, and liquefaction aspects of seismic hazards in the greater Boston area. Besides the application of these data for the Boston region, the data may be applicable throughout New England, through correlations with geologic units (similar to Ebel and Kim, 2006) or correlations with topographic slope (Wald and Allen, 2007), because few VS measurements are available in stable tectonic regions.Ebel and Hart (2001) used felt earthquake reports to infer amplification patterns throughout the greater Boston region and noted spatial correspondence with the dominant period and amplification factors obtained from ambient noise (horizontal-to-vertical ratios) by Kummer (1998). Britton (2003) compiled geotechnical borings in the area and produced a

  2. Site Characterization of the Source Physics Experiment Phase II Location Using Seismic Reflection Data

    SciTech Connect

    Sexton, Emily; Snelson, Catherine M; Chipman, Veraun D; Emer, Dudley; White, Bob; Emmit, Ryan; Wright, Al; Drellack, Sigmund; Huckins-Gang, Heather; Mercadante, Jennifer; Floyd, Michael; McGowin, Chris; Cothrun, Chris; Bonal, Nedra

    2013-12-05

    An objective of the Source Physics Experiment (SPE) is to identify low-yield nuclear explosions from a regional distance. Low-yield nuclear explosions can often be difficult to discriminate among the clutter of natural and man-made explosive events (e.g., earthquakes and mine blasts). The SPE is broken into three phases. Phase I has provided the first of the physics-based data to test the empirical models that have been used to discriminate nuclear events. The Phase I series of tests were placed within a highly fractured granite body. The evolution of the project has led to development of Phase II, to be placed within the opposite end member of geology, an alluvium environment, thereby increasing the database of waveforms to build upon in the discrimination models. Both the granite and alluvium sites have hosted nearby nuclear tests, which provide comparisons for the chemical test data. Phase III of the SPE is yet to be determined.

  3. Engineering study of 50 miscellaneous inactive underground radioactive waste tanks located at the Hanford Site, Washington

    SciTech Connect

    Freeman-Pollard, J.R.

    1994-03-02

    This engineering study addresses 50 inactive underground radioactive waste tanks. The tanks were formerly used for the following functions associated with plutonium and uranium separations and waste management activities in the 200 East and 200 West Areas of the Hanford Site: settling solids prior to disposal of supernatant in cribs and a reverse well; neutralizing acidic process wastes prior to crib disposal; receipt and processing of single-shell tank (SST) waste for uranium recovery operations; catch tanks to collect water that intruded into diversion boxes and transfer pipeline encasements and any leakage that occurred during waste transfer operations; and waste handling and process experimentation. Most of these tanks have not been in use for many years. Several projects have, been planned and implemented since the 1970`s and through 1985 to remove waste and interim isolate or interim stabilize many of the tanks. Some tanks have been filled with grout within the past several years. Responsibility for final closure and/or remediation of these tanks is currently assigned to several programs including Tank Waste Remediation Systems (TWRS), Environmental Restoration and Remedial Action (ERRA), and Decommissioning and Resource Conservation and Recovery Act (RCRA) Closure (D&RCP). Some are under facility landlord responsibility for maintenance and surveillance (i.e. Plutonium Uranium Extraction [PUREX]). However, most of the tanks are not currently included in any active monitoring or surveillance program.

  4. An Experiment to Locate the Site of TeV Flaring in M87

    SciTech Connect

    Harris, D.E.; Massaro, F.; Cheung, C.C.; Horns, D.; Raue, M.; Stawarz, L.; Wagner, S.; Colin, P.; Mazin, D.; Wagner, R.; Beilicke, M.; LeBohec, S.; Hui, M.; Mukherjee, R.; /Barnard Coll.

    2012-05-18

    We describe a Chandra X-ray target-of-opportunity project designed to isolate the site of TeV flaring in the radio galaxy M87. To date, we have triggered the Chandra observations only once (2010 April) and by the time of the first of our nine observations, the TeV flare had ended. However, we found that the X-ray intensity of the unresolved nucleus was at an elevated level for our first observation. Of the more than 60 Chandra observations we have made of the M87 jet covering nine years, the nucleus was measured at a comparably high level only three times. Two of these occasions can be associated with TeV flaring, and at the time of the third event, there were no TeV monitoring activities. From the rapidity of the intensity drop of the nucleus, we infer that the size of the emitting region is of order a few light days x the unknown beaming factor; comparable to the same sort of estimate for the TeV emitting region. We also find evidence of spectral evolution in the X-ray band which seems consistent with radiative losses affecting the non-thermal population of the emitting electrons within the unresolved nucleus.

  5. Microwave and X-ray observations of delayed brightenings at sites remote from the primary flare locations

    NASA Technical Reports Server (NTRS)

    Nakajima, H.; Dennis, B. R.; Hoyng, P.; Nelson, G.; Kosugi, T.; Kai, K.

    1984-01-01

    Five examples of solar flares observed with the 17-GHz interferometer at Nobeyama in which a secondary microwave burst occurred at a distance of 100,000 km to 1,000,000 km from the primary flare site are presented. The secondary microwave burst in all five cases had a similar time profile to the primary burst with a delay of 2 to 25 s. The velocity of a triggering agent inferred from this delay and spatial separation is 10,000 km to 100,000 km/s. The intensity of the secondary burst was a factor of 3 to 25 smaller than that of the primary burst in all events except for one case in which it was a factor of 2 larger. The polarization degree of the secondary burst at 17 GHz was 35%, significantly higher than the average value for typical impulsive bursts. Two of the events were accompanied by meterwave type III/V bursts located high in the corona between the primary and secondary sites. For two of the other events, X-ray images of he secondary source were obtained with the hard-X-ray imaging spectrometer on the Solar Maximum Mission. These observations strongly suggest that the distant microwave bursts were produced by electrons with energies of 10 keV to 100 keV which were channeled along a huge loop from the main flare site to the remote location.

  6. Risk assessment of soil-based exposures to plutonium at experimental sites located on the Nevada Test Site and adjoining areas

    SciTech Connect

    Layton, D.W.; Anspaugh, L.R.; Bogen, K.T.; Straume, T.

    1993-06-01

    In the late 1950s and early 1960s, a series of tests was conducted at or near the Nevada Test Site to study issues involving plutonium-bearing devices. These tests resulted in the dispersal of about 5 TBq of {sup 239,240}Pu on the surficial soils at the test locations. Access to the sites is strictly controlled; therefore, it does not constitute a threat to human health at the present time. However, because the residual {sup 239} Pu decays slowly (half-life of 24,110 y), the sites could indeed represent a long-term hazard if they are not remediated and if institutional controls are lost. To investigate the magnitude of the potential health risks for this no-remediation case, we defined three basic exposure scenarios that could bring individuals in contact with {sup 239,240}Pu at the sites: (1) a resident living in a subdivision located at a test site, (2) a resident farmer, and (3) a worker at a commercial facility. Our screening analyses indicated that doses to organs are dominated by the intemal deposition of Pu via the inhalation pathway, and thus our risk assessment focused on those factors that affect inhalation exposures and associated doses, including inhalation rates, activity patterns, tenure at a residence or occupation, indoor/outdoor air relationships, and resuspension outdoors. Cancer risks were calculated as a function of lifetime cumulative doses to the key target organs (i.e., bone surface, liver, and lungs) and risk factors for those organs. Uncertainties in the predicted cancer risks were analyzed using Monte-Carlo simulations of the probability distributions used to represent assessment parameters. The principal sources of uncertainty in the estimated risks were population mobility, the relationship between indoor and outdoor contaminant levels, and the dose and risk factors for bone, liver, and lung.

  7. A new insight into the nature of seasonal variations in coordinate time series of GPS sites located near active faults

    NASA Astrophysics Data System (ADS)

    Trofimenko, Sergey V.; Bykov, Victor G.; Shestakov, Nikolay V.; Grib, Nikolay N.; Takahashi, Hiroaki

    2016-09-01

    This study provides new insights into the nature of seasonal variations in coordinate time series of GPS sites located near active faults and methods of their modeling. Monthly averaged coordinate time series were analyzed for several pairs of collocated GPS sites situated near the active fault intersection area, in close proximity to the central part of the northern boundary of the Amurian plate and the vicinity of the San Andreas Fault zone. It is concluded that the observed seasonal variations are best described by a breather function which is one of the solutions of the well-known sine-Gordon equation. The obtained results suggest that, in this case, the source of seasonal variations may be caused by the appearance of solitary strain waves in the fault intersection system, which may be qualitatively treated as standing waves of compression-extension of the geological medium. Based on statistical testing, the limits of applicability of the suggested model have been established.

  8. A new insight into the nature of seasonal variations in coordinate time series of GPS sites located near active faults

    NASA Astrophysics Data System (ADS)

    Trofimenko, Sergey V.; Bykov, Victor G.; Shestakov, Nikolay V.; Grib, Nikolay N.; Takahashi, Hiroaki

    2016-05-01

    This study provides new insights into the nature of seasonal variations in coordinate time series of GPS sites located near active faults and methods of their modeling. Monthly averaged coordinate time series were analyzed for several pairs of collocated GPS sites situated near the active fault intersection area, in close proximity to the central part of the northern boundary of the Amurian plate and the vicinity of the San Andreas Fault zone. It is concluded that the observed seasonal variations are best described by a breather function which is one of the solutions of the well-known sine-Gordon equation. The obtained results suggest that, in this case, the source of seasonal variations may be caused by the appearance of solitary strain waves in the fault intersection system, which may be qualitatively treated as standing waves of compression-extension of the geological medium. Based on statistical testing, the limits of applicability of the suggested model have been established.

  9. On the location of the H+-extruding steps in site 2 of the mitochondrial electron transport chain.

    PubMed

    Alexandre, A; Galiazzo, F; Lehninger, A L

    1980-11-25

    The location of the H+-translocating reactions within energy-conserving Site 2 of the mitochondrial electron transport chain was evaluated from two sets of data. In the first, the H+/2e- ejection ratios and Ca2+/2e- uptake ratios were compared for electron flow from succinate dehydrogenase, whose active site is on the matrix side of the inner membrane and from glycerol phosphate dehydrogenase, whose active site is on the cytosolic side. In intact rat liver mitochondria both substrates yielded H+/2e- ejection ratios close to 4.0 and Ca2+/2e- uptake ratios close to 1.0 during antimycin-sensitive reduction of ferricyanide. With rat liver mitoplasts and ferricytochrome c as electron acceptor, both substrates again gave the same stoichiometric ratios. The second approach involved determination of the sidedness of H+ formation during electron flow from succinate to ferricyanide via bypass of the antimycin block of the cytochrome b.c1 complex provided by N,N,N',N'-tetramethyl-p-phenylenediamine (TMPD), under conditions in which the TMPD-TMPD+ couple does not act as a membrane-penetrating protonophore. Electron flow in this system was inhibited by 2-then-oyltrifluoroacetone, indicating that TMPD probably accepts electrons from ubiquinol. The 2 H+ formed in this system were not delivered into the matrix but appeared directly in the medium in the absence of a protonophore. To accommodate the available evidence on Site 2 substrates, it is concluded that the substrate hydrogens are first transferred to ubiquinone, 2 H+ per 2e then appear in the medium by protolytic dehydrogenation of a species of ubiquinol or ubiquinol-protein having the appropriate sidedness (designated Site 2A), and the other 2 H+ are translocated from the matrix to the medium on passage of 2e- through the cytochrome b x c1 complex (designated Site 2B). PMID:7430148

  10. Quantum Monte Carlo study of hard-core bosons in a pyrochlore lattice with six-site ring-exchange interactions

    NASA Astrophysics Data System (ADS)

    Tieman, Catherine; Rousseau, Valery

    Highly frustrated quantum systems on lattices can exhibit a wide variety of phases. In addition to the usual Mott insulating and superfluid phases, these systems can also produce some so-called ``exotic phases'', such as super-solid and valence-bond-solid phases. An example of particularly frustrated lattice is the pyrochlore structure, which is formed by corner-sharing tetrahedrons. Many real materials adopt this structure, for instance the crystal Cd2 Re2O7 , which exhibits superconducting properties. However, the complex structure of these materials combined with the complexity of the dominant interactions that describe them makes their analytical study difficult. Also, approximate methods, such as mean-field theory, fail to give a correct description of these systems. In this work, we report on the first exact quantum Monte Carlo study of a model of hard-core bosons in a pyrochlore lattice with six-site ring-exchange interactions, using the Stochastic Green Function (SGF) algorithm. We analyze the superfluid density and the structure factor as functions of the filling and ring-exchange interaction strength, and we map out the ground state phase diagram.

  11. 43 CFR 3832.91 - How do I amend a mining claim or site location if it exceeds the size limitations?

    Code of Federal Regulations, 2013 CFR

    2013-10-01

    ... location if it exceeds the size limitations? 3832.91 Section 3832.91 Public Lands: Interior Regulations... or site location if it exceeds the size limitations? (a) You may correct defects in your location of... public lands. It was developed to determine maximum allowable acreage for land entries (placer claims...

  12. 43 CFR 3832.91 - How do I amend a mining claim or site location if it exceeds the size limitations?

    Code of Federal Regulations, 2012 CFR

    2012-10-01

    ... location if it exceeds the size limitations? 3832.91 Section 3832.91 Public Lands: Interior Regulations... or site location if it exceeds the size limitations? (a) You may correct defects in your location of... public lands. It was developed to determine maximum allowable acreage for land entries (placer claims...

  13. An Inter-Comparison of Two Independent Site Test Interferometers Located in Goldstone, California: Initial Study Results

    NASA Technical Reports Server (NTRS)

    Morabito, David; D'Addario, Larry; Acosta, Roberto J.; Nessel, James A.

    2012-01-01

    Site Test Interferometers (STIs) have been deployed at two different locations at the NASA Deep Space Network (DSN) tracking complex in Goldstone, California. An STI measures the difference in path length between a geostationary satellite and two antennas on the Earth, producing a measure of atmospheric phase fluctuations over spatial distances comparable to those between elements of possible microwave phased arrays. The purposes of the Goldstone STIs are to assess the suitability of Goldstone as an array site and to statistically characterize atmospheric induced delay fluctuations for application to future array scenarios.The two STI's are separated by 13 km across the Goldstone complex. Each instrument is composed of two small-diameter antennas and associated electronics separated by approx. 200 meters in a principally east-west configuration. The antennas continuously observe signals emitted by geo-stationary satellites and produce data that contain information on the phase difference between signals received by both antennas. The fluctuation in delay (or path length difference) statistics derived from these data sets can be used to infer power loss for particular array configurations.We report on a comparison of the root mean square (RMS) phase delay statistics estimated over 10-minute intervals between the two Goldstone STIs. We have achieved good statistical agreement between the data acquired from the two STIs, given that each instrument is observing different satellites, at different frequencies, over different baseline lengths, with very different implementations, and are located 13 km apart in widely separated terrain at different geodetic altitudes.

  14. Symmetries of migration related segments of all [001] coincidence site lattice tilt boundaries in (001) projections for all holohedral cubic materials

    SciTech Connect

    Moeck, Peter; York, Bryant W.; Browning, Nigel D.

    2014-09-11

    Utilizing bicrystallography in two dimensions (2D), the symmetries of migration related segments of Coincidence Site Lattice (CSL) boundaries are derived for projections along their [001] tilt axis in grain boundaries of crystalline materials that possess the holohedral point symmetry of the cubic system (i.e. m3m). These kinds of “edge-on” projections are typical for atomic resolution imaging of such tilt boundaries with Transmission Electron Microscopes (TEM). This fact facilitates the visual confirmation of our predictions by recently published Zcontrast scanning TEM investigations [H. Yang et al., Phil. Mag. 93 (2013) 1219] and many other TEM studies.

  15. Organochlorine compounds in Purple Heron eggs (Ardea purpurea) nesting in sites located around a chlor-alkali plant (Ebro River).

    PubMed

    Huertas, David; Grimalt, Joan O; Jover, Lluís; Sanpera, Carola; Ruiz, Xavier

    2016-01-01

    Eggs of Purple Heron (Ardea purpurea) were collected from three sampled sites inside the Ebro River basin in years 2006 and 2007. These sites were located besides (Flix), upstream (Aiguabarreig) and downstream (Delta) a chlor-alkali plant. Organochlorine compounds (OCs) such as dichlorodiphenyltrichloroethanes (DDTs), polychlorobiphenyls (PCBs), polychlorostyrenes (PCSs), hexachlorobenzene (HCB), pentachlorobenzene (PeCB) and hexachlorocyclohexanes (HCHs) were analysed to assess what are the accumulation patterns of these compounds in aquatic migratory birds breeding in the area of influence of the emissions from this industrial installation. Comparison of the egg concentrations between the three sites show higher concentrations of compounds manufactured in the past in the factory (PCBs, p,p'-DDT) or by-products of OC synthesis (HCB, PeCB and PCSs) in Flix than in Aiguabarreig reflecting a clear influence from the emissions of the chlor-alkali plant. The eggs collected in the Ebro Delta showed higher concentrations of total DDTs (mainly p,p'-DDE) than in the reference site (Aiguabarreig) which could reflect past applications of this insecticide in the area for agriculture. In contrast, HCHs were found in higher concentrations in the Delta and Aiguabarreig than in the Flix Reservoir. These compounds have been used as insecticides in agriculture and were not manufactured in the chlor-alkali plant. The present results show that despite Purple Herons are migratory birds, the food web transfer of OCs during the breeding season is sufficient for the accumulation of these compounds in the eggs, leading to statistically significant concentration differences between sites. These differences are consistent with the emissions of these pollutants from industrial or agricultural sources to the aquatic environments. Some of the p,p'-DDE concentrations observed in the area nearby the chlor-alkali plant are above the threshold effects for reproductive impairment. PMID:26202210

  16. Edaphic factors trigger diverse AM fungal communities associated to exotic camellias in closely located Lake Maggiore (Italy) sites.

    PubMed

    Borriello, Roberto; Berruti, Andrea; Lumini, Erica; Della Beffa, Maria Teresa; Scariot, Valentina; Bianciotto, Valeria

    2015-05-01

    Camellia japonica L. is an acidophilic ornamental shrub of high economic value that has its center of origin in Japan and has been introduced in several European environmental niches. This exotic species forms arbuscular mycorrhizas (AM), known for their ability to positively affect plant growth. However, AM fungal communities associated to C. japonica in the field have never been characterized. For the first time, the AM fungal community naturally selected by C. japonica was screened in three sites located on the shores of Lake Maggiore (Italy), where specimens of this plant were introduced in the nineteenth century. Mycorrhizal levels were assessed, and the AM fungal communities associated to roots and soil were molecularly characterized based on the small subunit (SSU) rDNA region. The frequency of mycorrhizal roots was high in all sampled root systems (>90 %). Overall, 39 Operational Taxonomic Units (OTUs; 22 Glomerales, 9 Paraglomerales, 7 Archaeosporales, and 1 Diversisporales) were found in the root and soil samples. OTU richness did not significantly differ between the root and the soil niche (5.7 ± 0.6 and 8.0 ± 1.1 average OTUs per sample, respectively) and the three sites analyzed (7.5 ± 0.7, 5.2 ± 1.0, and 7.8 ± 1.5 average OTUs per sample in the three sites, respectively). The AM fungal community composition significantly differed between root-colonizing and soil-dwelling communities and among the three sites under study. Data show a major involvement of edaphic factors, such as available N sources, P, Mg, and K content in soil and soil compaction, in the structuring of the AM fungal communities. PMID:25253200

  17. Grand-canonical and canonical solution of self-avoiding walks with up to three monomers per site on the Bethe lattice.

    PubMed

    Oliveira, Tiago J; Stilck, Jürgen F; Serra, Pablo

    2009-10-01

    We solve a model of polymers represented by self-avoiding walks on a lattice, which may visit the same site up to three times in the grand-canonical formalism on the Bethe lattice. This may be a model for the collapse transition of polymers where only interactions between monomers at the same site are considered. The phase diagram of the model is very rich, displaying coexistence and critical surfaces, critical, critical end point, and tricritical lines, as well as a multicritical point. From the grand-canonical results, we present an argument to obtain the properties of the model in the canonical ensemble, and compare our results with simulations in the literature. We do actually find extended and collapsed phases, but the transition between them, composed by a line of critical end points and a line of tricritical points, separated by the multicritical point, is always continuous. This result is at variance with the simulations for the model, which suggest that part of the line should be a discontinuous transition. Finally, we discuss the connection of the present model with the standard model for the collapse of polymers (self-avoiding, self-attracting walks), where the transition between the extended and collapsed phases is a tricritical point. PMID:19905330

  18. Pattern Recognition of Adsorbing HP Lattice Proteins

    NASA Astrophysics Data System (ADS)

    Wilson, Matthew S.; Shi, Guangjie; Wüst, Thomas; Landau, David P.; Schmid, Friederike

    2015-03-01

    Protein adsorption is relevant in fields ranging from medicine to industry, and the qualitative behavior exhibited by course-grained models could shed insight for further research in such fields. Our study on the selective adsorption of lattice proteins utilizes the Wang-Landau algorithm to simulate the Hydrophobic-Polar (H-P) model with an efficient set of Monte Carlo moves. Each substrate is modeled as a square pattern of 9 lattice sites which attract either H or P monomers, and are located on an otherwise neutral surface. The fully enumerated set of 102 unique surfaces is simulated with each protein sequence. A collection of 27-monomer sequences is used- each of which is non-degenerate and protein-like. Thermodynamic quantities such as the specific heat and free energy are calculated from the density of states, and are used to investigate the adsorption of lattice proteins on patterned substrates. Research supported by NSF.

  19. Secondary Coincidence Site Lattice Model for Truncated Triangular β-Mg2Sn Precipitates in a Mg-Sn-Based Alloy

    NASA Astrophysics Data System (ADS)

    Shi, Z.-Z.; Dai, F.-Z.; Zhang, M.; Gu, X.-F.; Zhang, W.-Z.

    2013-06-01

    This article presents a model of a secondary coincidence site lattice (CSLΙΙ). It is applied to interpret a truncated triangular morphology of β-Mg2Sn precipitates in an Mg-Sn-based alloy. With a slight long-range strain being accommodated elastically, the distribution of good matching sites (GMS) on interfaces between the β-Mg2Sn precipitates and α-Mg matrix exhibits double periodicity. One is within GMS clusters, and the other is carried by the constrained-CSLΙΙ (CCSLΙΙ) points at the centers of the GMS clusters. The calculated results fully agree with the experimental results, including the irrational orientation relationship, the habit plane, and the irrational side facets. The preferred state of the interfaces, the preferred ledge height, and the preferred Burgers vectors of secondary dislocations have been discussed.

  20. Honeycomb lattices with defects

    NASA Astrophysics Data System (ADS)

    Spencer, Meryl A.; Ziff, Robert M.

    2016-04-01

    In this paper, we introduce a variant of the honeycomb lattice in which we create defects by randomly exchanging adjacent bonds, producing a random tiling with a distribution of polygon edges. We study the percolation properties on these lattices as a function of the number of exchanged bonds using an alternative computational method. We find the site and bond percolation thresholds are consistent with other three-coordinated lattices with the same standard deviation in the degree distribution of the dual; here we can produce a continuum of lattices with a range of standard deviations in the distribution. These lattices should be useful for modeling other properties of random systems as well as percolation.

  1. Effect of the location of Mn sites in ferromagnetic GaMnAs on its Curie temperature

    SciTech Connect

    Yu, K.M.; Walukiewicz, W.; Wojtowicz, T.; Kuryliszyn, I.; Liu, X.; Sasaki, Y.; Furdyna, J.K.

    2002-01-17

    We report a strong correlation between the location of Mn sites in ferromagnetic Ga{sub 1-x}Mn{sub x}As measured by channeling Rutherford backscattering and by particle induced x-ray emission experiments and its Curie temperature. The concentrations of free holes determined by electrochemical capacitance-voltage profiling and of uncompensated Mn{sup ++} spins determined from SQUID magnetization measurements are found to depend on the concentration of unstable defects involving highly mobile Mn interstitials. This leads to large variations in T{sub c} of Ga{sub 1-x}Mn{sub x}As when it is annealed at different temperatures in a narrow temperature range. The fact that annealing under various conditions has failed to produce Curie temperatures above {approx}110K is attributed to the existence of an upper limit on the free hole concentration in low-temperature-grown Ga{sub 1-x}Mn{sub x}As.

  2. Estimation of source apportionment and potential source locations of PM 2.5 at a west coastal IMPROVE site

    NASA Astrophysics Data System (ADS)

    Hwang, InJo; Hopke, Philip K.

    Particle composition data for PM 2.5 samples collected at Kalmiopsis Interagency Monitoring of Protected Visual Environments (IMPROVE) site in southwestern Oregon from March 2000 to May 2004 were analyzed to provide source identification and apportionment. A total of 493 samples were collected and 32 species were analyzed by particle induced X-ray emission, proton elastic scattering analysis, photon-induced X-ray fluorescence, ion chromatography, and thermal optical reflectance methods. Positive matrix factorization (PMF) was used to estimate the source profiles and their mass contributions. The PMF modeling identified nine sources. In the Kalmiopsis site, the average mass was apportioned to wood/field burning (38.4%), secondary sulfate (26.9%), airborne soil including Asian dust (8.6 %), secondary nitrate (7.6%), fresh sea salt (5.8%), OP-rich sulfate (4.9%), aged sea salt (4.5 %), gasoline vehicle (1.9%), and diesel emission (1.4%). The potential source contribution function (PSCF) was then used to help identify likely locations of the regional sources of pollution. The PSCF map for wood/field burning indicates there is a major potential source area in the Siskiyou County and eastern Oregon. The potential source locations for secondary sulfate are found in western Washington, northwestern Oregon, and the near shore Pacific Ocean where there are extensive shipping lanes. It was not possible to extract a profile directly attributable to ship emissions, but indications of their influence are seen in the secondary sulfate and aged sea salt compositions.

  3. The role of semiochemicals in short-range location of aggregation sites in Adalia bipunctata (Coleoptera, Coccinellidae).

    PubMed

    Susset, Eline C; Ramon-Portugal, Felipe; Hemptinne, Jean-Louis; Dewhirst, Sarah Y; Birkett, Michael A; Magro, Alexandra

    2013-05-01

    To survive unfavorable periods, ladybird beetles form conspicuous aggregations in specific microsites, with these locations remaining the same year after year. This constancy of location leads to the hypothesis that semiochemicals are involved in the attraction and aggregation of ladybirds to the microsite. In this study, we identified two types of semiochemicals that could play key roles in the attraction and aggregation formation of the two-spotted ladybird, Adalia bipunctata. We first isolated and identified three alkylmethoxypyrazines from A. bipunctata and tested the behavioral responses of diapausing ladybirds to these chemicals in a four-way olfactometer. This revealed that 2-isobutyl-3-methoxypyrazine, on its own or as part of a two-component mixture with 2-isopropyl-3-methoxypyrazine, elicited a positive behavioral response, causing arrestment of diapausing A. bipunctata. As ladybirds are in contact with each other in aggregations, we investigated the role of cuticular hydrocarbons (CHCs) in driving the cohesion and maintenance of aggregation. When an extract of CHCs from diapausing ladybirds was deposited near an alkylmethoxypyrazine source, ladybirds spent more time in the vicinity of the source. We identified a set of CHCs specific to diapausing A. bipunctata. Alkylmethoxyyrazines and CHCs thus deliver information to diapausing ladybirds searching for an aggregation site, as well as mediating several other behaviors throughout the ladybird's life cycle. Chemical parsimony is discussed. PMID:23620127

  4. Locating active-site hydrogen atoms in d-xylose isomerase: Time-of-flight neutron diffraction

    PubMed Central

    Katz, Amy K.; Li, Xinmin; Carrell, H. L.; Hanson, B. Leif; Langan, Paul; Coates, Leighton; Schoenborn, Benno P.; Glusker, Jenny P.; Bunick, Gerard J.

    2006-01-01

    Time-of-flight neutron diffraction has been used to locate hydrogen atoms that define the ionization states of amino acids in crystals of d-xylose isomerase. This enzyme, from Streptomyces rubiginosus, is one of the largest enzymes studied to date at high resolution (1.8 Å) by this method. We have determined the position and orientation of a metal ion-bound water molecule that is located in the active site of the enzyme; this water has been thought to be involved in the isomerization step in which d-xylose is converted to d-xylulose or d-glucose to d-fructose. It is shown to be water (rather than a hydroxyl group) under the conditions of measurement (pH 8.0). Our analyses also reveal that one lysine probably has an −NH2-terminal group (rather than NH3+). The ionization state of each histidine residue also was determined. High-resolution x-ray studies (at 0.94 Å) indicate disorder in some side chains when a truncated substrate is bound and suggest how some side chains might move during catalysis. This combination of time-of-flight neutron diffraction and x-ray diffraction can contribute greatly to the elucidation of enzyme mechanisms. PMID:16707576

  5. Efficient chain moves for Monte Carlo simulations of a wormlike DNA model: Excluded volume, supercoils, site juxtapositions, knots, and comparisons with random-flight and lattice models

    NASA Astrophysics Data System (ADS)

    Liu, Zhirong; Chan, Hue Sun

    2008-04-01

    We develop two classes of Monte Carlo moves for efficient sampling of wormlike DNA chains that can have significant degrees of supercoiling, a conformational feature that is key to many aspects of biological function including replication, transcription, and recombination. One class of moves entails reversing the coordinates of a segment of the chain along one, two, or three axes of an appropriately chosen local frame of reference. These transformations may be viewed as a generalization, to the continuum, of the Madras-Orlitsky-Shepp algorithm for cubic lattices. Another class of moves, termed T±2, allows for interconversions between chains with different lengths by adding or subtracting two beads (monomer units) to or from the chain. Length-changing moves are generally useful for conformational sampling with a given site juxtaposition, as has been shown in previous lattice studies. Here, the continuum T±2 moves are designed to enhance their acceptance rate in supercoiled conformations. We apply these moves to a wormlike model in which excluded volume is accounted for by a bond-bond repulsion term. The computed autocorrelation functions for the relaxation of bond length, bond angle, writhe, and branch number indicate that the new moves lead to significantly more efficient sampling than conventional bead displacements and crankshaft rotations. A close correspondence is found in the equilibrium ensemble between the map of writhe computed for pair of chain segments and the map of site juxtapositions or self-contacts. To evaluate the more coarse-grained freely jointed chain (random-flight) and cubic lattice models that are commonly used in DNA investigations, twisting (torsional) potentials are introduced into these models. Conformational properties for a given superhelical density σ may then be sampled by computing the writhe and using White's formula to relate the degree of twisting to writhe and σ. Extensive comparisons of contact patterns and knot probabilities

  6. Efficient chain moves for Monte Carlo simulations of a wormlike DNA model: excluded volume, supercoils, site juxtapositions, knots, and comparisons with random-flight and lattice models.

    PubMed

    Liu, Zhirong; Chan, Hue Sun

    2008-04-14

    We develop two classes of Monte Carlo moves for efficient sampling of wormlike DNA chains that can have significant degrees of supercoiling, a conformational feature that is key to many aspects of biological function including replication, transcription, and recombination. One class of moves entails reversing the coordinates of a segment of the chain along one, two, or three axes of an appropriately chosen local frame of reference. These transformations may be viewed as a generalization, to the continuum, of the Madras-Orlitsky-Shepp algorithm for cubic lattices. Another class of moves, termed T+/-2, allows for interconversions between chains with different lengths by adding or subtracting two beads (monomer units) to or from the chain. Length-changing moves are generally useful for conformational sampling with a given site juxtaposition, as has been shown in previous lattice studies. Here, the continuum T+/-2 moves are designed to enhance their acceptance rate in supercoiled conformations. We apply these moves to a wormlike model in which excluded volume is accounted for by a bond-bond repulsion term. The computed autocorrelation functions for the relaxation of bond length, bond angle, writhe, and branch number indicate that the new moves lead to significantly more efficient sampling than conventional bead displacements and crankshaft rotations. A close correspondence is found in the equilibrium ensemble between the map of writhe computed for pair of chain segments and the map of site juxtapositions or self-contacts. To evaluate the more coarse-grained freely jointed chain (random-flight) and cubic lattice models that are commonly used in DNA investigations, twisting (torsional) potentials are introduced into these models. Conformational properties for a given superhelical density sigma may then be sampled by computing the writhe and using White's formula to relate the degree of twisting to writhe and sigma. Extensive comparisons of contact patterns and knot

  7. LONG-TERM STABILITY OF THE LOCAL GROUND CONTROL NETWORK AT THE CO-LOCATION SITE OF MEDICINA

    NASA Astrophysics Data System (ADS)

    Abbondanza, C.; Sarti, P.; Legrand, J.

    2009-12-01

    ITRF combinations rely on the availability of accurate tie vectors linking reference points of space geodetic techniques. Co-located instruments are assumed to move consistently and no local relative motion is taken into account. Instabilities may degrade the quality of the co-location itself and perturb the result of ITRF combinations. This work aims to determine the stability of the local ground control network at Medicina (Italy) with independent surveying methods. The observatory hosts a co-location between a VLBI telescope and two GPS antennas, MEDI and MSEL. It is located in the Po Plain where thick layers of clays are the prevalent soil characteristics. Hence, provision of long term stability of geodetic monuments is a challenge and monitoring their stability is an issue. MEDI and the VLBI station regularly contribute to the determination of ITRF, while MSEL is part of the EUREF network. A set of five tie vectors observations linking the VLBI and MEDI reference points was acquired between 2001 and 2007. It is our main tool for performing local deformation analysis. Additionally, the GPS time series of MEDI and MSEL were used to cross check and confirm the local instability detected by terrestrial methods. To achieve a rigorous and reliable investigation of the local stability, multi-epoch terrestrial observations were homogeneously processed according to common parameterizations in a consistent reference frame. Similarly, continuous GPS observations from MEDI and MSEL were analysed according to the new EPN reprocessing strategy in order to monitor the short baseline between MEDI and MSEL; to spotlight any change in its length. Both approaches confirm differential motions at the site which can be related to monument instabilities originated by the particularly unfavourable local geological setting and the inapt design of the monuments foundation. The monuments move non homogeneously at rates reaching up to 1.6 mm/year, this value being comparable to intra

  8. Quantised vortices in polariton lattices

    NASA Astrophysics Data System (ADS)

    Berloff, Natalia

    2015-11-01

    The first comprehensive treatment of quantised vorticity in the light of research on vortices in modern fluid mechanics appeared in Russell Donnelly seminal research papers and summarized in his 1991 book ``Quantized Vortices in Helium II''. Recently quantized vortices have been studied in polariton condensates. Polaritons are the mixed light-matter quasi-particles that are formed in the strong exciton-photon coupling regime. Under non-resonant optical excitation rapid relaxation of carriers and bosonic stimulation result in the formation of a non-equilibrium polariton condensate characterized by a single many-body wave-function, therefore, naturally possessing quantized vortices. Polariton condensates can be imprinted into any two-dimensional lattice by spatial modulation of the pumping laser and form vortices via interacting outfows from the pumping sites. Optically pumped polariton condensates can be injected in lattice configurations with arbitrary density profiles offering the possibility to control the kinetics of the condensate and therefore the number and location of vortices. I will present some new developments in theoretical and experimental studies of quantized vortices in polariton condensates and discuss possible practical implementations of polariton lattices.

  9. Massive Depletion of Bovine Leukemia Virus Proviral Clones Located in Genomic Transcriptionally Active Sites during Primary Infection

    PubMed Central

    Gillet, Nicolas A.; Renotte, Nathalie; Alvarez, Irene; Trono, Karina; Willems, Luc

    2013-01-01

    Deltaretroviruses such as human T-lymphotropic virus type 1 (HTLV-1) and bovine leukemia virus (BLV) induce a persistent infection that remains generally asymptomatic but can also lead to leukemia or lymphoma. These viruses replicate by infecting new lymphocytes (i.e. the infectious cycle) or via clonal expansion of the infected cells (mitotic cycle). The relative importance of these two cycles in viral replication varies during infection. The majority of infected clones are created early before the onset of an efficient immune response. Later on, the main replication route is mitotic expansion of pre-existing infected clones. Due to the paucity of available samples and for ethical reasons, only scarce data is available on early infection by HTLV-1. Therefore, we addressed this question in a comparative BLV model. We used high-throughput sequencing to map and quantify the insertion sites of the provirus in order to monitor the clonality of the BLV-infected cells population (i.e. the number of distinct clones and abundance of each clone). We found that BLV propagation shifts from cell neoinfection to clonal proliferation in about 2 months from inoculation. Initially, BLV proviral integration significantly favors transcribed regions of the genome. Negative selection then eliminates 97% of the clones detected at seroconversion and disfavors BLV-infected cells carrying a provirus located close to a promoter or a gene. Nevertheless, among the surviving proviruses, clone abundance positively correlates with proximity of the provirus to a transcribed region. Two opposite forces thus operate during primary infection and dictate the fate of long term clonal composition: (1) initial integration inside genes or promoters and (2) host negative selection disfavoring proviruses located next to transcribed regions. The result of this initial response will contribute to the proviral load set point value as clonal abundance will benefit from carrying a provirus in transcribed

  10. Equipartition Gamma-Ray Blazars and the Location of the Gamma-Ray Emission Site in 3C 279

    NASA Astrophysics Data System (ADS)

    Dermer, Charles D.; Cerruti, Matteo; Lott, Benoit; Boisson, Catherine; Zech, Andreas

    2014-02-01

    Blazar spectral models generally have numerous unconstrained parameters, leading to ambiguous values for physical properties like Doppler factor δD or fluid magnetic field B'. To help remedy this problem, a few modifications of the standard leptonic blazar jet scenario are considered. First, a log-parabola function for the electron distribution is used. Second, analytic expressions relating energy loss and kinematics to blazar luminosity and variability, written in terms of equipartition parameters, imply δD, B', and the peak electron Lorentz factor \\gamma _{pk}^\\prime. The external radiation field in a blazar is approximated by Lyα radiation from the broad-line region (BLR) and ≈0.1 eV infrared radiation from a dusty torus. When used to model 3C 279 spectral energy distributions from 2008 and 2009 reported by Hayashida et al., we derive δD ~ 20-30, B' ~ few G, and total (IR + BLR) external radiation field energy densities u ~ 10-2-10-3 erg cm-3, implying an origin of the γ-ray emission site in 3C 279 at the outer edges of the BLR. This is consistent with the γ-ray emission site being located at a distance R <~ Γ2 ct var ~ 0.1(Γ/30)2(t var/104 s) pc from the black hole powering 3C 279's jets, where t var is the variability timescale of the radiation in the source frame, and at farther distances for narrow-jet and magnetic-reconnection models. Excess >~ 5 GeV γ-ray emission observed with Fermi LAT from 3C 279 challenges the model, opening the possibility of a second leptonic component or a hadronic origin of the emission. For low hadronic content, absolute jet powers of ≈10% of the Eddington luminosity are calculated.