Sample records for absolute electron impact

  1. Absolute total and partial dissociative cross sections of pyrimidine at electron and proton intermediate impact velocities

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wolff, Wania, E-mail: wania@if.ufrj.br; Luna, Hugo; Sigaud, Lucas

    Absolute total non-dissociative and partial dissociative cross sections of pyrimidine were measured for electron impact energies ranging from 70 to 400 eV and for proton impact energies from 125 up to 2500 keV. MOs ionization induced by coulomb interaction were studied by measuring both ionization and partial dissociative cross sections through time of flight mass spectrometry and by obtaining the branching ratios for fragment formation via a model calculation based on the Born approximation. The partial yields and the absolute cross sections measured as a function of the energy combined with the model calculation proved to be a useful toolmore » to determine the vacancy population of the valence MOs from which several sets of fragment ions are produced. It was also a key point to distinguish the dissociation regimes induced by both particles. A comparison with previous experimental results is also presented.« less

  2. Electronic Absolute Cartesian Autocollimator

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B.

    2006-01-01

    An electronic absolute Cartesian autocollimator performs the same basic optical function as does a conventional all-optical or a conventional electronic autocollimator but differs in the nature of its optical target and the manner in which the position of the image of the target is measured. The term absolute in the name of this apparatus reflects the nature of the position measurement, which, unlike in a conventional electronic autocollimator, is based absolutely on the position of the image rather than on an assumed proportionality between the position and the levels of processed analog electronic signals. The term Cartesian in the name of this apparatus reflects the nature of its optical target. Figure 1 depicts the electronic functional blocks of an electronic absolute Cartesian autocollimator along with its basic optical layout, which is the same as that of a conventional autocollimator. Referring first to the optical layout and functions only, this or any autocollimator is used to measure the compound angular deviation of a flat datum mirror with respect to the optical axis of the autocollimator itself. The optical components include an illuminated target, a beam splitter, an objective or collimating lens, and a viewer or detector (described in more detail below) at a viewing plane. The target and the viewing planes are focal planes of the lens. Target light reflected by the datum mirror is imaged on the viewing plane at unit magnification by the collimating lens. If the normal to the datum mirror is parallel to the optical axis of the autocollimator, then the target image is centered on the viewing plane. Any angular deviation of the normal from the optical axis manifests itself as a lateral displacement of the target image from the center. The magnitude of the displacement is proportional to the focal length and to the magnitude (assumed to be small) of the angular deviation. The direction of the displacement is perpendicular to the axis about which the

  3. Absolute cross sections for the ionization-excitation of helium by electron impact

    NASA Astrophysics Data System (ADS)

    Bellm, S.; Lower, J.; Weigold, E.; Bray, I.; Fursa, D. V.; Bartschat, K.; Harris, A. L.; Madison, D. H.

    2008-09-01

    In a recent publication we presented detailed experimental and theoretical results for the electron-impact-induced ionization of ground-state helium atoms. The purpose of that work was to refine theoretical approaches and provide further insight into the Coulomb four-body problem. Cross section ratios were presented for transitions leading to excited states, relative to those leading to the ground state, of the helium ion. We now build on that study by presenting individual relative triple-differential ionization cross sections (TDCSs) for an additional body of experimental data measured at lower values of scattered-electron energies. This has been facilitated through the development of new electron-gun optics which enables us to accurately characterize the spectrometer transmission at low energies. The experimental results are compared to calculations resulting from a number of different approaches. For ionization leading to He+(1s2)1S , cross sections are calculated by the highly accurate convergent close-coupling (CCC) method. The CCC data are used to place the relative experimental data on to an absolute scale. TDCSs describing transitions to the excited states are calculated through three different approaches, namely, through a hybrid distorted- wave+R -matrix (close-coupling) model, through the recently developed four-body distorted-wave model, and by a first Born approximation calculation. Comparison of the first- and second-order theories with experiment allows for the accuracy of the different theoretical approaches to be assessed and gives insight into which physical aspects of the problem are most important to accurately model.

  4. Absolute differential cross sections for electron impact excitation of the 10.8-11.5 eV energy-loss states of CO2

    NASA Astrophysics Data System (ADS)

    Green, M. A.; Teubner, P. J. O.; Campbell, L.; Brunger, M. J.; Hoshino, M.; Ishikawa, T.; Kitajima, M.; Tanaka, H.; Itikawa, Y.; Kimura, M.; Buenker, R. J.

    2002-02-01

    Absolute differential cross sections (DCSs) for electron impact excitation of electronic states of CO2 in the 10.8-11.5 eV energy-loss range are reported. These data were obtained at the incident electron energies 20,30,60,100 and 200 eV and over the scattered electron angular range 3.5°-90°. The accuracy of our experimental methods has been established independently by using several different normalization techniques at both Sophia and Flinders Universities. Generalized oscillator strengths were derived from our measured DCSs and then extrapolated to zero momentum transfer, in order to determine the optical oscillator strengths. These optical oscillator strengths, where possible, are compared with the results from previous measurements and calculations.

  5. Absolute electron-impact total ionization cross sections of chlorofluoromethanes

    NASA Astrophysics Data System (ADS)

    Martínez, Roberto; Sierra, Borja; Redondo, Carolina; Rayo, María N. Sánchez; Castaño, Fernando

    2004-12-01

    An experimental study is reported on the electron-impact total ionization cross sections (TICSs) of CCl4, CCl3F, CCl2F2, and CClF3 molecules. The kinetic energy of the colliding electrons was in the 10-85 eV range. TICSs were obtained as the sum of the partial ionization cross sections of all fragment ions, measured and identified in a linear double focusing time-of-flight mass spectrometer. The resulting TICS profiles—as a function of the electron-impact energy—have been compared both with those computed by ab initio and (semi)empirical methods and with the available experimental data. The computational methods used include the binary-encounter-Bethe (BEB) modified to include atoms with principal quantum numbers n⩾3, the Deutsch and Märk (DM) formalism, and the modified additivity rule (MAR). It is concluded that both modified BEB and DM methods fit the experimental TICS for (CF4), CClF3, CCl2F2, CCl3F, and CCl4 to a high accuracy, in contrast with the poor accord of the MAR method. A discussion on the factors influencing the discrepancies of the fittings is presented.

  6. Absolute cross sections for electronic excitation of condensed tetrahydrofuran (THF) by 11-16 eV electrons.

    PubMed

    Lemelin, V; Bass, A D; Cloutier, P; Sanche, L

    2016-11-07

    Absolute cross section (CS) data on the interaction of low energy electrons with DNA and its molecular constituents are required as input parameters in Monte-Carlo type simulations, for several radiobiological applications. Previously [V. Lemelin et al., J. Chem. Phys. 144, 074701 (2016)], we measured absolute vibrational CSs for low-energy electron scattering from condensed tetrahydrofuran, a convenient surrogate for the deoxyribose. Here we report absolute electronic CSs for energy losses of between 6 and 11.5 eV, by electrons with energies between 11 and 16 eV. The variation of these CSs with incident electron energy shows no evidence of transient anion states, consistent with theoretical and other experimental results, indicating that initial electron capture leading to DNA strand breaks occurs primarily on DNA bases or the phosphate group.

  7. Electron-impact excitation of the low-lying electronic states of HCN

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Tanaka, H.; Srivastava, S. K.; Wicke, B. G.

    1977-01-01

    The first study of the low-energy electron-impact excitation of low-lying electronic transitions in the HCN molecule is reported. Measurements were made at incident electron energies of 11.6 and 21.6 eV in the energy-loss range of 3-10 eV, and at scattering angles of 20-130 deg. Inelastic scattering spectra were placed on the absolute cross-section scale by determining first the ratio of inelastic-to-elastic scattering cross sections, and then separately measuring the absolute elastic scattering cross section. Several new electronic transitions are observed which are intrinsically overlapped in the molecule itself. Assignments of these electronic transitions are suggested. These assignments are based on present spectroscopic and cross-sections measurements, high-energy electron scattering spectra, optical absorption spectra, and ab initio molecular orbital calculations.

  8. Photoionization and electron-impact ionization of Ar5+

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wang, J.C.; Lu, M.; Esteves, D.

    2007-02-27

    Absolute cross sections for photoionization andelectron-impact Photionization of Ar5+ have been measuredusing twodifferent interacting-beams setups. The spectra consist of measurementsof the yield of products dueto single ionization as a function ofelectron or photon energy. In addition, absolute photoionization andelectron-impact ionization cross sections were measured to normalize themeasured Ar6+ product-ion yield spectra. In the energy range from 90 to111 eV, both electron-impact ionization and photoionization of Ar5+aredominated by indirect 3s subshell excitation-autoionization. In theenergy range from 270 to 285 eV, resonances due to 2p-3dexcitation-autoionization are prominent in the photoionization spectrum.In the range from 225 to 335 eV, an enhancement due tomore » 2p-nl (n>2>excitations are evident in the electron-impactionization cross section.The electron and photon impact data show some features due to excitationof the same intermediate autoionizing states.« less

  9. Absolute Measurements of Field Enhanced Dielectronic Recombination and Electron Impact Excitation

    NASA Astrophysics Data System (ADS)

    Savin, Daniel Wolf

    Absolute measurements have been made of the dielectronic recombination (DR) rate coefficient for C^ {3+}, via the 2s-2p core -excitation, in an external electric field of 11.4 +/- 0.9(1sigma) V cm ^{-1}; and of the electron impact excitation (EIE) rate coefficient for C ^{3+}(2s-2p) at energies near threshold. The ion-rest-frame FWHM of the electron energy spread was 1.74 +/- 0.22(1sigma) eV. The measured DR rate, at a mean electron energy of 8.26 +/- 0.07(1sigma ) eV, was (2.76+/- 0.75)times 10^{-10} cm^{3 } s^{-1}. The uncertainty quoted for the DR rate is the total experimental uncertainty at a 1sigma<=vel. The present DR result appears to agree with an intermediate coupling calculation which uses the isolated-resonance, single-configuration approximation. In comparing with theory, a semi-classical formula was used to determine which recombined ions were field-ionized by the 4.65 kV cm^{-1} fields in the final-charge-state analyzer and not detected. A more precise treatment of field-ionization, which includes the lifetime of the high Rydberg C^{2+} ions in the external field and the time evolution and rotation of the fields experienced by the recombined ions, is needed before a definitive comparison between experiment and theory can be made. For the EIE results, at an ion-rest-frame energy of 10.10 eV, the measured rate coefficient was (7.79+/- 2.10)times 10^{ -8} cm^3 s^ {-1}. The measured cross section was (4.15+/- 1.12)times 10^{ -16} cm^2. The uncertainties quoted here represent the total experimental uncertainty at a 90 percent confidence level. Good agreement is found with other measurements. Agreement is not good with Coulomb -Born with exchange and two-state close-coupling calculations which fall outside the 90-percent-confidence uncertainty limits. Agreement is better with a nine-state close-coupling calculation which lies at the extreme of the uncertainty limits. Taking into account previous measurements in C ^{3+} and also a measurement of EIE in Be

  10. Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

    NASA Astrophysics Data System (ADS)

    Kaya, Ismet I.; Eberl, Karl

    2007-05-01

    A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two-dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal can be interpreted as the analog of Bernoulli’s effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

  11. Absolute charge calibration of scintillating screens for relativistic electron detection

    NASA Astrophysics Data System (ADS)

    Buck, A.; Zeil, K.; Popp, A.; Schmid, K.; Jochmann, A.; Kraft, S. D.; Hidding, B.; Kudyakov, T.; Sears, C. M. S.; Veisz, L.; Karsch, S.; Pawelke, J.; Sauerbrey, R.; Cowan, T.; Krausz, F.; Schramm, U.

    2010-03-01

    We report on new charge calibrations and linearity tests with high-dynamic range for eight different scintillating screens typically used for the detection of relativistic electrons from laser-plasma based acceleration schemes. The absolute charge calibration was done with picosecond electron bunches at the ELBE linear accelerator in Dresden. The lower detection limit in our setup for the most sensitive scintillating screen (KODAK Biomax MS) was 10 fC/mm2. The screens showed a linear photon-to-charge dependency over several orders of magnitude. An onset of saturation effects starting around 10-100 pC/mm2 was found for some of the screens. Additionally, a constant light source was employed as a luminosity reference to simplify the transfer of a one-time absolute calibration to different experimental setups.

  12. Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons

    PubMed Central

    Chen, Wenzhuang; Chen, Shiliang; Dong, Yanfang; Cloutier, Pierre; Sanche, Léon

    2016-01-01

    Absolute cross sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions. To determine CSs for various conformational DNA damage induced by 2–20 eV electrons, we investigated the influence of the attenuation length (AL) and penetration factor (f) using a mathematical model. Solid films of super-coiled plasmid DNA with thicknesses of 10, 15 and 20 nm were irradiated with 4.6, 5.6, 9.6 and 14.6 eV electrons. DNA conformational changes were quantified by gel electrophoresis, and the respective yields were extrapolated from exposure–response curves. The absolute CS, AL and f values were generated by applying the model developed by Rezaee et al. The values of AL were found to lie between 11 and 16 nm with the maximum at 14.6 eV. The absolute CSs for the loss of the supercoiled (LS) configuration and production of crosslinks (CL), single strand breaks (SSB) and double strand breaks (DSB) induced by 4.6, 5.6, 9.6 and 14.6 eV electrons are obtained. The CSs for SSB are smaller, but similar to those for LS, indicating that SSB are the main conformational damage. The CSs for DSB and CL are about one order of magnitude smaller than those of LS and SSB. The value of f is found to be independent of electron energy, which allows extending the absolute CSs for these types of damage within the range 2–20 eV, from previous measurements of effective CSs. When comparison is possible, the absolute CSs are found to be in good agreement with those obtained from previous similar studies with double-stranded DNA. The high values of the absolute CSs of 4.6 and 9.6 eV provide quantitative evidence for the high efficiency of low energy electrons to induce DNA damage via the formation of transient anions. PMID:27878170

  13. Absolute cross-sections for DNA strand breaks and crosslinks induced by low energy electrons.

    PubMed

    Chen, Wenzhuang; Chen, Shiliang; Dong, Yanfang; Cloutier, Pierre; Zheng, Yi; Sanche, Léon

    2016-12-07

    Absolute cross sections (CSs) for the interaction of low energy electrons with condensed macromolecules are essential parameters to accurately model ionizing radiation induced reactions. To determine CSs for various conformational DNA damage induced by 2-20 eV electrons, we investigated the influence of the attenuation length (AL) and penetration factor (f) using a mathematical model. Solid films of supercoiled plasmid DNA with thicknesses of 10, 15 and 20 nm were irradiated with 4.6, 5.6, 9.6 and 14.6 eV electrons. DNA conformational changes were quantified by gel electrophoresis, and the respective yields were extrapolated from exposure-response curves. The absolute CS, AL and f values were generated by applying the model developed by Rezaee et al. The values of AL were found to lie between 11 and 16 nm with the maximum at 14.6 eV. The absolute CSs for the loss of the supercoiled (LS) configuration and production of crosslinks (CL), single strand breaks (SSB) and double strand breaks (DSB) induced by 4.6, 5.6, 9.6 and 14.6 eV electrons are obtained. The CSs for SSB are smaller, but similar to those for LS, indicating that SSB are the main conformational damage. The CSs for DSB and CL are about one order of magnitude smaller than those of LS and SSB. The value of f is found to be independent of electron energy, which allows extending the absolute CSs for these types of damage within the range 2-20 eV, from previous measurements of effective CSs. When comparison is possible, the absolute CSs are found to be in good agreement with those obtained from previous similar studies with double-stranded DNA. The high values of the absolute CSs of 4.6 and 9.6 eV provide quantitative evidence for the high efficiency of low energy electrons to induce DNA damage via the formation of transient anions.

  14. Absolute Scale Quantitative Off-Axis Electron Holography at Atomic Resolution

    NASA Astrophysics Data System (ADS)

    Winkler, Florian; Barthel, Juri; Tavabi, Amir H.; Borghardt, Sven; Kardynal, Beata E.; Dunin-Borkowski, Rafal E.

    2018-04-01

    An absolute scale match between experiment and simulation in atomic-resolution off-axis electron holography is demonstrated, with unknown experimental parameters determined directly from the recorded electron wave function using an automated numerical algorithm. We show that the local thickness and tilt of a pristine thin WSe2 flake can be measured uniquely, whereas some electron optical aberrations cannot be determined unambiguously for a periodic object. The ability to determine local specimen and imaging parameters directly from electron wave functions is of great importance for quantitative studies of electrostatic potentials in nanoscale materials, in particular when performing in situ experiments and considering that aberrations change over time.

  15. Absolute Negative Resistance Induced by Directional Electron-Electron Scattering in a Two-Dimensional Electron Gas

    NASA Astrophysics Data System (ADS)

    Kaya, Ismet I.

    2007-03-01

    A ballistic conductor is restricted to have positive three terminal resistance just as a Drude conductor. Intercarrier scattering does not influence the conductivity of the latter transport regime and does not exist in the former. However, as the electron energies increased, in the intermediate regime, single or few intercarrier scattering events starts to dominate the transport properties of a conductor with sufficiently small dimensions. A three-terminal device formed by two electrostatic barriers crossing an asymmetrically patterned two dimensional electron gas displays an unusual potential depression at the middle contact, yielding absolute negative resistance. The device displays momentum and current transfer ratios that far exceed unity. The observed reversal of the current or potential in the middle terminal is interpreted as the analog of Bernoulli's effect in a Fermi liquid. The results are explained by directional scattering of electrons in two dimensions.

  16. Absolute cross-section measurements of inner-shell ionization

    NASA Astrophysics Data System (ADS)

    Schneider, Hans; Tobehn, Ingo; Ebel, Frank; Hippler, Rainer

    1994-12-01

    Cross section ratios for K- and L-shell ionization of thin silver and gold targets by positron and electron impact have been determined at projectile energies of 30 70 keV. The experimental results are confirmed by calculations in plane wave Born approximation (PWBA) which include an electron exchange term and account for the deceleration or acceleration of the incident projectile in the nuclear field of the target atom. We report first absolute cross sections for K- and L-shell ionization of silver and gold targets by lepton impact in the threshold region. We have measured the corresponding cross sections for electron (e-) impact with an electron gun and the same experimental set-up.

  17. Electron impact contribution to infrared NO emissions in auroral conditions

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.

    2007-11-01

    Infrared emissions from nitric oxide, other than nightglow, are observed in aurora, principally due to a chemiluminescent reaction between excited nitrogen atoms and oxygen molecules that produces vibrationally excited NO. The rates for this chemiluminescent reaction have recently been revised. Based on new measurements of electron impact vibrational excitation of NO, it has been suggested that electron impact may also be significant in producing auroral NO emissions. We show results of a detailed calculation which predicts the infrared spectrum observed in rocket measurements, using the revised chemiluminescent rates and including electron impact excitation. For emissions from the second vibrational level and above, the shape of the spectrum can be reproduced within the statistical errors of the analysis of the measurements, although there is an unexplained discrepancy in the absolute value of the emissions. The inclusion of electron impact improves the agreement of the shape of the predicted spectrum with the measurements by accounting for part of the previously unexplained peak in emissions from the first vibrational level.

  18. Differential cross sections for electron-impact excitation of the electronic states of pyrimidine

    NASA Astrophysics Data System (ADS)

    Brunger, Michael; Jones, Darryl; Bellm, Susan

    2012-06-01

    Pyrimidine (C4N2H4) is an important molecule, as it forms the basis of larger biomolecules, such as the DNA bases thymine, cytosine and uracil. There is a pressing demand for low-energy electron scattering data from such biological analogs in order to model radiation induced damage [1]. We therefore present the first measurements for absolute differential cross section data for low-energy electron-impact excitation of the electronic states of pyrimidine. The present measurements were performed using a crossed-beam apparatus [2] for incident electron energies ranging between 15 to 50eV while covering a 10 to 90^o angular range. Here the absolute scale has been determined through a normalisation to the recently measured elastic scattering differential cross section data for pyrimidine [3]. [1] F. Ferreira da Silva, D. Almeida, G. Martins, A. R. Milosavljevic, B. P. Marinkovic, S. V. Hoffmann, N. J. Mason, Y. Nunes, G. Garcia and P. Limao-Vieira, Phys Chem Chem Phys 12, 6717 (2010). [2] M. J. Brunger and P. J. O. Teubner, Phys Rev A 41, 1413 (1990). [3] P. Palihawadana, J. Sullivan, M. Brunger, C. Winstead, V. McKoy, G. Garcia, F. Blanco and S. Buckman, Phys Rev A 84, 062702 (2011).

  19. Secondary Electron Emission From Solar Cell Coverslides And Its Effect On Absolute Vehicle Charging

    NASA Astrophysics Data System (ADS)

    Ferguson, Dale C.

    2011-10-01

    It has often been stated that earthed conductive solar cell coverslides are the best way to prevent electrostatic discharges on space solar arrays in GEO. While it is true that such coverslides will prevent differential charging on the solar arrays, it will be shown through NASCAP- 2k simulations that the secondary electron emission of such coverslides is very important for absolute vehicle charging. In particular, carbon nanotube coatings, due to the extremely low secondary electron emission from carbon, may exacerbate absolute vehicle charging. However, if they are earthed, because of their conductivity they may minimize differential charging and the possibility of arcing elsewhere on the spacecraft. Such results may also be true for insulative coverslides if spacecraft thermal blankets are made of materials with high secondary electron emission. Finally, photoemission from coverslides is investigated, with regard to anti-reflection coatings. Surfaces which reflect UV can have low photoemission, while those that absorb may have higher photoemission rates. Thus, anti-reflection coatings may lead to higher absolute spacecraft charging rates. NASCAP-2k simulations will be used to investigate these dependences for realistic spacecraft.

  20. Multiple electron processes of He and Ne by proton impact

    NASA Astrophysics Data System (ADS)

    Terekhin, Pavel Nikolaevich; Montenegro, Pablo; Quinto, Michele; Monti, Juan; Fojon, Omar; Rivarola, Roberto

    2016-05-01

    A detailed investigation of multiple electron processes (single and multiple ionization, single capture, transfer-ionization) of He and Ne is presented for proton impact at intermediate and high collision energies. Exclusive absolute cross sections for these processes have been obtained by calculation of transition probabilities in the independent electron and independent event models as a function of impact parameter in the framework of the continuum distorted wave-eikonal initial state theory. A binomial analysis is employed to calculate exclusive probabilities. The comparison with available theoretical and experimental results shows that exclusive probabilities are needed for a reliable description of the experimental data. The developed approach can be used for obtaining the input database for modeling multiple electron processes of charged particles passing through the matter.

  1. Absolute vibrational cross sections for 1-19 eV electron scattering from condensed tetrahydrofuran (THF).

    PubMed

    Lemelin, V; Bass, A D; Cloutier, P; Sanche, L

    2016-02-21

    Absolute cross sections (CSs) for vibrational excitation by 1-19 eV electrons impacting on condensed tetrahydrofuran (THF) were measured with a high-resolution electron energy loss spectrometer. Experiments were performed under ultra-high vacuum (3 × 10(-11) Torr) at a temperature of about 20 K. The magnitudes of the vibrational CSs lie within the 10(-17) cm(2) range. Features observed near 4.5, 9.5, and 12.5 eV in the incident energy dependence of the CSs were compared to the results of theoretical calculations and other experiments on gas and solid-phase THF. These three resonances are attributed to the formation of shape or core-excited shape resonances. Another maximum observed around 2.5 eV is not found in the calculations but has been observed in gas-phase studies; it is attributed to the formation of a shape resonance.

  2. Absolute Calibration of Image Plate for electrons at energy between 100 keV and 4 MeV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Chen, H; Back, N L; Eder, D C

    2007-12-10

    The authors measured the absolute response of image plate (Fuji BAS SR2040) for electrons at energies between 100 keV to 4 MeV using an electron spectrometer. The electron source was produced from a short pulse laser irradiated on the solid density targets. This paper presents the calibration results of image plate Photon Stimulated Luminescence PSL per electrons at this energy range. The Monte Carlo radiation transport code MCNPX results are also presented for three representative incident angles onto the image plates and corresponding electron energies depositions at these angles. These provide a complete set of tools that allows extraction ofmore » the absolute calibration to other spectrometer setting at this electron energy range.« less

  3. Excitation of atomic nitrogen by electron impact

    NASA Technical Reports Server (NTRS)

    Stone, E. J.; Zipf, E. C.

    1972-01-01

    Absolute cross sections were measured for the excitation of the N I(1134, 1164, 1168, 1200, 1243, and 1743 A) multiplets by electron impact on atomic nitrogen. The presence of vibrationally excited molecular nitrogen in the discharged gas was confirmed, and its effect on the measurements is discussed. The ratio of the oscillator strengths of the 1200 and 1134 A resonance transitions is presented, as well as the branching ratio for the N I(1311/1164 A) multiplets. Striking differences in the distribution of intensity between the spectra of atomic nitrogen and molecular nitrogen excited by energetic electrons suggest an optical method for measuring the density of atomic nitrogen in the upper atmosphere.

  4. Assignment of absolute stereostructures through quantum mechanics electronic and vibrational circular dichroism calculations.

    PubMed

    Dai, Peng; Jiang, Nan; Tan, Ren-Xiang

    2016-01-01

    Elucidation of absolute configuration of chiral molecules including structurally complex natural products remains a challenging problem in organic chemistry. A reliable method for assigning the absolute stereostructure is to combine the experimental circular dichroism (CD) techniques such as electronic and vibrational CD (ECD and VCD), with quantum mechanics (QM) ECD and VCD calculations. The traditional QM methods as well as their continuing developments make them more applicable with accuracy. Taking some chiral natural products with diverse conformations as examples, this review describes the basic concepts and new developments of QM approaches for ECD and VCD calculations in solution and solid states.

  5. Metastable Oxygen Production by Electron-Impact of Oxygen

    NASA Astrophysics Data System (ADS)

    Hein, J. D.; Malone, C. P.; Johnson, P. V.; Kanik, I.

    2014-12-01

    Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of oxygen-containing molecules plays a significant role in the dynamics of planetary atmospheres (Earth, Mars, Europa, Io, Enceladus) and cometary bodies (Hale-Bopp). The electron-impact excitation channels to O(1S) and O(1D) are important for determining energy partitioning and dynamics. To reliably model natural phenomena and interpret observational data, the accurate determination of underlying collision processes (cross sections, dissociation dynamics) through fundamental experimental studies is essential. The detection of metastable species in laboratory experiments requires a novel approach. Typical radiative de-excitation detection techniques cannot be performed due to the long-lived nature of excited species, and conventional particle detectors are insensitive to the low internal energies O(1S) and O(1D). We have recently constructed an apparatus to detect and characterize metastable oxygen production by electron impact using the "rare gas conversion technique." Recent results will be presented, including absolute excitation functions for target gases O2, CO, CO2, and N2O. This work was performed at the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with the National Aeronautics and Space Administration (NASA). Financial support through NASA's OPR, PATM, and MFRP programs, as well as the NASA Postdoctoral Program (NPP) are gratefully acknowledged.

  6. Electron-impact ionization of atomic hydrogen at incident electron energies of 15.6, 17.6, 25, and 40 eV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Childers, J. G.; James, K. E.; Hughes, M.

    2003-09-01

    Absolute doubly differential cross sections for the electron-impact ionization of atomic hydrogen have been measured from near threshold to intermediate energies. The measurements are calibrated to the well-established, accurate differential cross section for electron-impact excitation of the atomic hydrogen transition H(1{sup 2}S{yields}2{sup 2}S+2{sup 2}P). In these experiments background secondary electrons are suppressed by moving the atomic hydrogen target source to and from the collision region. Measurements cover the incident electron energy range of 14.6-40 eV, for scattering angles of 10 degree sign -120 degree sign and are found to be in very good agreement with the results of the mostmore » advanced theoretical models--the convergent close-coupling model and the exterior complex scaling model.« less

  7. Qualitative analysis of the helical electronic energy of inherently chiral calix[4]arenes: an approach to effectively assign their absolute configuration.

    PubMed

    Zheng, Shuang; Chang, Ming-Liang; Zhou, Jing; Fu, Jing-Wei; Zhang, Qing-Wei; Li, Shao-Yong; Qiao, Wei; Liu, Jun-Min

    2014-06-03

    For all microhelices on aromatic rings of inherently chiral calix[4]arene, an expression was derived from one approximation and one hypothesis on the basis of the electron-on-a-helix model of Tinoco and Woody as follows: 1/E = μ(H - KΔα2), where μ = 1 for the right-handed microhelix and μ = -1 for the left-handed microhelix; and H and K are constant and greater than zero. The expression correlates microhelical electronic energy (E) with the atom polarizability difference (Δα) on both microhelix ends, which intuitively and clearly shows the impact of helical substituent polarizability on helical electronic energy. The case analysis almost entirely proves that the qualitative analysis of the helical electronic energy of inherently chiral calix[4]arenes with the expression is scientific and can be used to effectively assign their absolute configuration.

  8. Determination of differential cross sections for electron-impact excitation of electronic states of molecular oxygen

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Green, M. A.; Brunger, M. J.; Teubner, P. J.; Cartwright, D. C.

    2000-02-01

    The development and initial results of a method for the determination of differential cross sections for electron scattering by molecular oxygen are described. The method has been incorporated into an existing package of computer programs which, given spectroscopic factors, dissociation energies and an energy-loss spectrum for electron-impact excitation, determine the differential cross sections for each electronic state relative to that of the elastic peak. Enhancements of the original code were made to deal with particular aspects of electron scattering from O2, such as the overlap of vibrational levels of the ground state with transitions to excited states, and transitions to levels close to and above the dissocation energy in the Herzberg and Schumann-Runge continua. The utility of the code is specifically demonstrated for the ``6-eV states'' of O2, where we report absolute differential cross sections for their excitation by 15-eV electrons. In addition an integral cross section, derived from the differential cross section measurements, is also reported for this excitation process and compared against available theoretical results. The present differential and integral cross sections for excitation of the ``6-eV states'' of O2 are the first to be reported in the literature for electron-impact energies below 20 eV.

  9. Electron impact vibrational excitation of carbon monoxide in the upper atmospheres of Mars and Venus

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Allan, M.; Brunger, M. J.

    2011-09-01

    Infrared emission from CO in the upper atmospheres of Mars, Venus and several other planets is a subject of current theoretical and experimental interest. Electron impact excitation makes a contribution that has not been included in previous studies. Given this, and recent new measurements of absolute cross sections for low-energy electron impact excitation of the vibrational levels of the ground state of CO, results from calculations are presented showing the contribution of electron impact relative to emissions by other mechanisms. It is demonstrated that emissions due to the impact of thermal, photo- and auroral electrons are generally small compared to sunlight-driven (fluorescence and photolysis) emissions, but with some exceptions. It is also shown that thermal-electron emissions may dominate over other processes at nighttime at Mars and that auroral emissions certainly do so. While measurements and other calculations do not appear to be available for Venus, the volume emission rates presented should be valuable in planning such measurements.

  10. Measurements of Electron Impact Excitation Cross Sections at the Harvard-Smithsonian Center for Astrophysics

    NASA Technical Reports Server (NTRS)

    Gardner, L. D.; Kohl, J. L.

    2006-01-01

    The analysis of absolute spectral line intensities and intensity ratios with spectroscopic diagnostic techniques provides empirical determinations of chemical abundances, electron densities and temperatures in astrophysical objects. Since spectral line intensities and their ratios are controlled by the excitation rate coefficients for the electron temperature of the observed astrophysical structure, it is imperative that one have accurate values for the relevant rate coefficients. Here at the Harvard-Smithsonian Center for Astrophysics, we have been carrying out measurements of electron impact excitation (EIE) for more than 25 years.

  11. Absolute vibrational excitation cross sections for 1-18 eV electron scattering from condensed dimethyl phosphate (DMP)

    NASA Astrophysics Data System (ADS)

    Lemelin, V.; Bass, A. D.; Wagner, J. R.; Sanche, L.

    2017-12-01

    Absolute cross sections (CSs) for vibrational excitation by 1-18 eV electrons incident on condensed dimethyl phosphate (DMP) were measured with a high-resolution electron energy loss (EEL) spectrometer. Absolute CSs were extracted from EEL spectra of DMP condensed on multilayer film of Ar held at about 20 K under ultra-high vacuum (˜1 × 10-11 Torr). Structures observed in the energy dependence of the CSs around 2, 4, 7, and 12 eV were compared with previous results of gas- and solid-phase experiments and with theoretical studies on dimethyl phosphate and related molecules. These structures were attributed to the formation of shape resonances.

  12. Energy dispersive X-ray analysis on an absolute scale in scanning transmission electron microscopy.

    PubMed

    Chen, Z; D'Alfonso, A J; Weyland, M; Taplin, D J; Allen, L J; Findlay, S D

    2015-10-01

    We demonstrate absolute scale agreement between the number of X-ray counts in energy dispersive X-ray spectroscopy using an atomic-scale coherent electron probe and first-principles simulations. Scan-averaged spectra were collected across a range of thicknesses with precisely determined and controlled microscope parameters. Ionization cross-sections were calculated using the quantum excitation of phonons model, incorporating dynamical (multiple) electron scattering, which is seen to be important even for very thin specimens. Copyright © 2015 Elsevier B.V. All rights reserved.

  13. Low-energy electron-impact ionization of helium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Schow, E.; Hazlett, K.; Childers, J. G.

    2005-12-15

    Normalized doubly differential cross sections for the electron-impact ionization of helium at low energies are presented. The data are taken at the incident electron energies of 26.3, 28.3, 30.3, 32.5, 34.3, 36.5, and 40.7 eV and for scattering angles of 10 deg. -130 deg. The measurements involve the use of the moveable target method developed at California State University Fullerton to accurately determine the continuum background in the energy-loss spectra. Normalization of experimental data is made on a relative scale to well-established experimental differential cross sections for excitation of the n=2 manifold of helium and then on an absolute scalemore » to the well-established total ionization cross sections of Shah et al. [J. Phys. B 21, 2751 (1988)]. Comparisons are made with available experimental data and the results of the convergent close-coupling theory.« less

  14. Electron impact cross sections for the 2,2P state excitation of lithium

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Trajmar, S.; Register, D. F.

    1982-01-01

    Electron impact excitation of the 2p 2P state of Li was studied at 10, 20, 60, 100, 150 and 200 eV. Relative differential cross sections in the angular range 3-120 deg were measured and then normalized to the absolute scale by using the optical f value. Integral and momentum transfer cross sections were obtained by extrapolating the differential cross sections to 0 deg and to 180 deg. The question of normalizing electron-metal-atom collision cross sections in general was examined and the method of normalization to optical f values in particular was investigated in detail. It has been concluded that the extrapolation of the apparent generalized oscillator strength (obtained from the measured differential cross sections) to the zero momentum transfer limit with an expression using even powers of the momentum transfer and normalization of the limit to the optical f value yields reliable absolute cross sections.

  15. Intermediate energy cross sections for electron-impact vibrational-excitation of pyrimidine

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, D. B.; Ellis-Gibbings, L.; García, G.

    2015-09-07

    We report differential cross sections (DCSs) and integral cross sections (ICSs) for electron-impact vibrational-excitation of pyrimidine, at incident electron energies in the range 15–50 eV. The scattered electron angular range for the DCS measurements was 15°–90°. The measurements at the DCS-level are the first to be reported for vibrational-excitation in pyrimidine via electron impact, while for the ICS we extend the results from the only previous condensed-phase study [P. L. Levesque, M. Michaud, and L. Sanche, J. Chem. Phys. 122, 094701 (2005)], for electron energies ⩽12 eV, to higher energies. Interestingly, the trend in the magnitude of the lower energymore » condensed-phase ICSs is much smaller when compared to the corresponding gas phase results. As there is no evidence for the existence of any shape-resonances, in the available pyrimidine total cross sections [Baek et al., Phys. Rev. A 88, 032702 (2013); Fuss et al., ibid. 88, 042702 (2013)], between 10 and 20 eV, this mismatch in absolute magnitude between the condensed-phase and gas-phase ICSs might be indicative for collective-behaviour effects in the condensed-phase results.« less

  16. Dissociative excitation of vacuum ultraviolet emission features by electron impact on molecular gases. 3: CO2

    NASA Technical Reports Server (NTRS)

    Mumma, M. J.; Borst, W. L.; Zipf, E. C.

    1972-01-01

    Vacuum ultraviolet multiplets of C I, C II, and O I were produced by electron impact of CO2. Absolute emission cross sections for these multiplets were measured from threshold to 350 eV. The electrostatically focussed electron gun used in this series of experiments is described in detail. The atomic multiplets which were produced by dissociative excitation of CO2 and the cross sections at 100 eV are given. The dependence of the excitation functions on electron energy shows that these multiplets are produced by electric-dipole-allowed transitions in CO2.

  17. Electron impact ionization of O2 and the interference effect from forward-backward asymmetry

    NASA Astrophysics Data System (ADS)

    Chowdhury, Madhusree Roy; Tribedi, Lokesh C.

    2017-08-01

    Absolute double differential cross sections (DDCSs) of secondary electrons emitted from O2 under the impact of 7 keV electrons were measured for different emission angles between 30° and 145° having energies from 1-600 eV. The forward-backward angular asymmetry was observed from angular distribution of the DDCS of secondary electrons. The asymmetry parameter, thus obtained from the DDCS of two complementary angles, showed a clear signature of interference oscillation. The Cohen-Fano model of Young type electron interference at a molecular double slit is found to provide a good fit to the observed oscillatory structures. The present observation is in qualitative agreement with the recent results obtained from photoionization.

  18. Excited-state structure and electronic dephasing time of Nile blue from absolute resonance Raman intensities

    NASA Astrophysics Data System (ADS)

    Lawless, Mary K.; Mathies, Richard A.

    1992-06-01

    Absolute resonance Raman cross sections are measured for Nile blue 690 perchlorate dissolved in ethylene glycol with excitation at 514, 531, and 568 nm. These values and the absorption spectrum are modeled using a time-dependent wave packet formalism. The excited-state equilibrium geometry changes are quantitated for 40 resonance Raman active modes, seven of which (590, 1141, 1351, 1429, 1492, 1544, and 1640 cm-1 ) carry 70% of the total resonance Raman intensity. This demonstrates that in addition to the prominent 590 and 1640 cm-1 modes, a large number of vibrational degrees of freedom are Franck-Condon coupled to the electronic transition. After exposure of the explicit vibrational progressions, the residual absorption linewidth is separated into its homogeneous [350 cm-1 half-width at half-maximum (HWHM)] and inhomogeneous (313 cm-1 HWHM) components through an analysis of the absolute Raman cross sections. The value of the electronic dephasing time derived from this study (25 fs) compares well to previously published results. These data should be valuable in multimode modeling of femtosecond experiments on Nile blue.

  19. Absolute cross section for low-energy-electron damage to condensed macromolecules: A case study of DNA

    PubMed Central

    Rezaee, Mohammad; Cloutier, Pierre; Bass, Andrew D.; Michaud, Marc; Hunting, Darel J.; Sanche, Léon

    2013-01-01

    Cross sections (CSs) for the interaction of low-energy electrons (LEE) with condensed macromolecules are essential parameters for accurate modeling of radiation-induced molecular decomposition and chemical synthesis. Electron irradiation of dry nanometer-scale macromolecular solid films has often been employed to measure CSs and other quantitative parameters for LEE interactions. Since such films have thicknesses comparable with electron thermalization distances, energy deposition varies throughout the film. Moreover, charge accumulation occurring inside the films shields a proportion of the macromolecules from electron irradiation. Such effects complicate the quantitative comparison of the CSs obtained in films of different thicknesses and limit the applicability of such measurements. Here, we develop a simple mathematical model, termed the molecular survival model, that employs a CS for a particular damage process together with an attenuation length related to the total CS, to investigate how a measured CS might be expected to vary with experimental conditions. As a case study, we measure the absolute CS for the formation of DNA strand breaks (SBs) by electron irradiation at 10 and 100 eV of lyophilized plasmid DNA films with thicknesses between 10 and 30 nm. The measurements are shown to depend strongly on the thickness and charging condition of the nanometer-scale films. Such behaviors are in accord with the model and support its validity. Via this analysis, the CS obtained for SB damage is nearly independent of film thickness and charging effects. In principle, this model can be adapted to provide absolute CSs for electron-induced damage or reactions occurring in other molecular solids across a wider range of experimental conditions. PMID:23030950

  20. Absolute measurements of the electronic transition moments of seven band systems of the C2 molecule. Ph.D. Thesis - York Univ., Toronto

    NASA Technical Reports Server (NTRS)

    Cooper, D. M.

    1979-01-01

    Electronic transition moments of seven C2 singlet and triplet band systems in the 0.2-1.2 micron spectral region were measured. The measurements were made in emission behind incident shock waves in C2H2-argon mixtures. Narrow bandpass radiometers were used to obtain absolute measurements of shock-excited C2 radiation from which absolute electronic transition moments are derived by a synthetic spectrum analysis. New results are reported for the Ballik-Ramsay, Phillips, Swan, Deslandres-d'Azambuja, Fox-Herzberg, Mulliken, and Freymark systems.

  1. Electron-impact dissociative excitation and ionization of N{sub 2}D{sup +}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fogle, M.; Bahati, E. M.; Bannister, M. E.

    Absolute cross sections for electron-impact dissociation of N{sub 2}D{sup +} producing N{sub 2}{sup +}, ND{sup +}, and N{sup +} ion fragments were measured in the 5- to 100-eV range using a crossed electron-ion beams technique. In the 5- to 20-eV region, in which dissociative excitation (DE) is the principal contributing mechanism, N{sub 2}{sup +} production dominates. The N{sub 2}{sup +} + D dissociation channel shows a large resonant-like structure in the DE cross section, as observed previously in electron impact dissociation of triatomic dihydride species [M. Fogle, E. M. Bahati, M. E. Bannister, S. H. M. Deng, C. R. Vane,more » R. D. Thomas, and V. Zhaunerchyk, Phys. Rev. A 82, 042720 (2010)]. In the dissociative ionization (DI) region, 20- to 100-eV, N{sub 2}{sup +}, ND{sup +}, and N{sup +} ion fragment production are comparable. The observance of the ND{sup +} and N{sup +} ion fragments indicate breaking of the N - N bond along certain dissociation channels.« less

  2. A rack-mounted precision waveguide-below-cutoff attenuator with an absolute electronic readout

    NASA Technical Reports Server (NTRS)

    Cook, C. C.

    1974-01-01

    A coaxial precision waveguide-below-cutoff attenuator is described which uses an absolute (unambiguous) electronic digital readout of displacement in inches in addition to the usual gear driven mechanical counter-dial readout in decibels. The attenuator is rack-mountable and has the input and output RF connectors in a fixed position. The attenuation rate for 55, 50, and 30 MHz operation is given along with a discussion of sources of errors. In addition, information is included to aid the user in making adjustments on the attenuator should it be damaged or disassembled for any reason.

  3. High Resolution Emission Spectroscopy of the Alpha Pi-1 - Chi Sigma-1(+) Fourth Positive Band System of CO from Electron Impact

    NASA Technical Reports Server (NTRS)

    Beegle, Luther W.; Ajello, Joseph M.; James, Geoffrey K.; Alvarez, Marcos; Dziczek, Dariusz

    2000-01-01

    We report electron-impact induced fluorescence spectra [300 mA full width at half maximum (FWHM)] of CO for 20 and 100 eV impact energies of the spectral region of 1300 to 2050 A and high resolution spectra (FWHM) of the v'=5 to v"=l and the v'=3 to v"=O bands showing that the rotational structure of the band system are modeled accurately. The excitation function of the (0,1) band (1597 A) was measured from electron impact in the energy range from threshold to 750 eV and placed on an absolute scale from modem calibration standards.

  4. Dissociative Excitation of Acetylene Induced by Electron Impact: Excitation-emission Cross-sections

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Országh, Juraj; Danko, Marián; Čechvala, Peter

    The optical emission spectrum of acetylene excited by monoenergetic electrons was studied in the range of 190–660 nm. The dissociative excitation and dissociative ionization associated with excitation of the ions initiated by electron impact were dominant processes contributing to the spectrum. The spectrum was dominated by the atomic lines (hydrogen Balmer series, carbon) and molecular bands (CH(A–X), CH(B–X), CH{sup +}(B–A), and C{sub 2}). Besides the discrete transitions, we have detected the continuum emission radiation of ethynyl radical C{sub 2}H(A–X). For most important lines and bands of the spectrum we have measured absolute excitation-emission cross sections and determined the energy thresholdsmore » of the particular dissociative channels.« less

  5. Analysis of multiple scattering contributions in electron-impact ionization of molecular hydrogen

    NASA Astrophysics Data System (ADS)

    Ren, Xueguang; Hossen, Khokon; Wang, Enliang; Pindzola, M. S.; Dorn, Alexander; Colgan, James

    2017-10-01

    We report a combined experimental and theoretical study on the low-energy (E 0 = 31.5 eV) electron-impact ionization of molecular hydrogen (H2). Triple differential cross sections are measured for a range of fixed emission angles of one outgoing electron between {θ }1=-70^\\circ and -130° covering the full 4π solid angle of the second electron. The energy sharing of the outgoing electrons varies from symmetric ({E}1={E}2=8 eV) to highly asymmetric (E 1 = 1 eV and E 2 = 15 eV). In addition to the binary and recoil lobes, a structure is observed perpendicular to the incoming beam direction which is due to multiple scattering of the projectile inside the molecular potential. The absolutely normalized experimental cross sections are compared with results from the time-dependent close-coupling (TDCC) calculations. Molecular alignment dependent TDCC results demonstrate that these structures are only present if the molecule axis is lying in the scattering plane.

  6. A new time of flight mass spectrometer for absolute dissociative electron attachment cross-section measurements in gas phase

    NASA Astrophysics Data System (ADS)

    Chakraborty, Dipayan; Nag, Pamir; Nandi, Dhananjay

    2018-02-01

    A new time of flight mass spectrometer (TOFMS) has been developed to study the absolute dissociative electron attachment (DEA) cross section using a relative flow technique of a wide variety of molecules in gas phase, ranging from simple diatomic to complex biomolecules. Unlike the Wiley-McLaren type TOFMS, here the total ion collection condition has been achieved without compromising the mass resolution by introducing a field free drift region after the lensing arrangement. The field free interaction region is provided for low energy electron molecule collision studies. The spectrometer can be used to study a wide range of masses (H- ion to few hundreds atomic mass unit). The mass resolution capability of the spectrometer has been checked experimentally by measuring the mass spectra of fragment anions arising from DEA to methanol. Overall performance of the spectrometer has been tested by measuring the absolute DEA cross section of the ground state SO2 molecule, and the results are satisfactory.

  7. Absolute cross section for electron-impact ionization of He (1 s 2 s 3S)

    NASA Astrophysics Data System (ADS)

    Génévriez, Matthieu; Jureta, Jozo J.; Defrance, Pierre; Urbain, Xavier

    2017-07-01

    We present an experimental determination of the electron-impact ionization cross section of the 1 s 2 s 3S state of helium, for which there is a serious long-lasting discrepancy between theory and experiment. A technique for the production of a fast, intense beam of helium in the 1 s 2 s 3S state only has been developed for this purpose, based on photodetachment of the He- anion. The cross section is measured using the animated crossed beam technique. The present results are much lower than the experimental data of Dixon et al. [J. Phys. B 9, 2617 (1976), 10.1088/0022-3700/9/15/013] and are in excellent agreement with the calculation of Fursa and Bray [J. Phys. B 36, 1663 (2003), 10.1088/0953-4075/36/8/317].

  8. Atomic, Molecular, and Optical Physics: Optical Excitation Function of H(1s-2p) Produced by electron Impact from Threshold to 1.8 keV

    NASA Technical Reports Server (NTRS)

    James, G. K.; Slevin, J. A.; Shemansky, D. E.; McConkey, J. W.; Bray, I.; Dziczek, D.; Kanik, I.; Ajello, J. M.

    1997-01-01

    The optical excitation function of prompt Lyman-Alpha radiation, produced by electron impact on atomic hydrogen, has been measured over the extended energy range from threshold to 1.8 keV. Measurements were obtained in a crossed-beams experiment using both magnetically confined and electrostatically focused electrons in collision with atomic hydrogen produced by an intense discharge source. A vacuum-ultraviolet mono- chromator system was used to measure the emitted Lyman-Alpha radiation. The absolute H(1s-2p) electron impact excitation cross section was obtained from the experimental optical excitation function by normalizing to the accepted optical oscillator strength, with corrections for polarization and cascade. Statistical and known systematic uncertainties in our data range from +/- 4% near threshold to +/- 2% at 1.8 keV. Multistate coupling affecting the shape of the excitation function up to 1 keV impact energy is apparent in both the present experimental data and present theoretical results obtained with convergent close- coupling (CCC) theory. This shape function effect leads to an uncertainty in absolute cross sections at the 10% level in the analysis of the experimental data. The derived optimized absolute cross sections are within 7% of the CCC calculations over the 14 eV-1.8 keV range. The present CCC calculations converge on the Bethe- Fano profile for H(1s-2p) excitation at high energy. For this reason agreement with the CCC values to within 3% is achieved in a nonoptimal normalization of the experimental data to the Bethe-Fano profile. The fundamental H(1s-2p) electron impact cross section is thereby determined to an unprecedented accuracy over the 14 eV - 1.8 keV energy range.

  9. Absolute cross section for loss of supercoiled topology induced by 10 eV electrons in highly uniform /DNA/1,3-diaminopropane films deposited on highly ordered pyrolitic graphite

    PubMed Central

    Boulanouar, Omar; Fromm, Michel; Bass, Andrew D.; Cloutier, Pierre; Sanche, Léon

    2013-01-01

    It was recently shown that the affinity of doubly charged, 1–3 diaminopropane (Dap2+) for DNA permits the growth on highly ordered pyrolitic graphite (HOPG) substrates, of plasmid DNA films, of known uniform thickness [O. Boulanouar, A. Khatyr, G. Herlem, F. Palmino, L. Sanche, and M. Fromm, J. Phys. Chem. C 115, 21291–21298 (2011)]. Post-irradiation analysis by electrophoresis of such targets confirms that electron impact at 10 eV produces a maximum in the yield of single strand breaks that can be associated with the formation of a DNA− transient anion. Using a well-adapted deterministic survival model for the variation of electron damage with fluence and film thickness, we have determined an absolute cross section for strand-break damage by 10 eV electrons and inelastic scattering attenuation length in DNA-Dap complex films. PMID:23927289

  10. Absolute cross section measurements for the scattering of low- and intermediate-energy electrons from PF3. I. Elastic scattering

    NASA Astrophysics Data System (ADS)

    Hishiyama, N.; Hoshino, M.; Blanco, F.; García, G.; Tanaka, H.

    2017-12-01

    We report absolute elastic differential cross sections (DCSs) for electron collisions with phosphorus trifluoride, PF3, molecules (e- + PF3) in the impact energy range of 2.0-200 eV and over a scattering angle range of 10°-150°. Measured angular distributions of scattered electron intensities were normalized by reference to the elastic DCSs of He. Corresponding integral and momentum-transfer cross sections were derived by extrapolating the angular range from 0° to 180° with the help of a modified phase-shift analysis. In addition, due to the large dipole moment of the considered molecule, the dipole-Born correction for the forward scattering angles has also been applied. As a part of this study, independent atom model calculations in combination with screening corrected additivity rule were also performed for elastic and inelastic (electronic excitation plus ionization) scattering using a complex optical potential method. Rotational excitation cross sections have been estimated with a dipole-Born approximation procedure. Vibrational excitations are not considered in this calculation. Theoretical data, at the differential and integral levels, were found to reasonably agree with the present experimental results. Furthermore, we explore the systematics of the elastic DCSs for the four-atomic trifluoride molecules of XF3 (X = B, N, and P) and central P-atom in PF3, showing that, owing to the comparatively small effect of the F-atoms, the present angular distributions of elastic DCSs are essentially dominated by the characteristic of the central P-atom at lower impact energies. Finally, these quantitative results for e- - PF3 collisions were compiled together with the previous data available in the literature in order to obtain a cross section dataset for modeling purposes. To comprehensively describe such a considerable amount of data, we proceed by first discussing, in this paper, the vibrationally elastic scattering processes whereas vibrational and electronic

  11. Variance computations for functional of absolute risk estimates.

    PubMed

    Pfeiffer, R M; Petracci, E

    2011-07-01

    We present a simple influence function based approach to compute the variances of estimates of absolute risk and functions of absolute risk. We apply this approach to criteria that assess the impact of changes in the risk factor distribution on absolute risk for an individual and at the population level. As an illustration we use an absolute risk prediction model for breast cancer that includes modifiable risk factors in addition to standard breast cancer risk factors. Influence function based variance estimates for absolute risk and the criteria are compared to bootstrap variance estimates.

  12. Variance computations for functional of absolute risk estimates

    PubMed Central

    Pfeiffer, R.M.; Petracci, E.

    2011-01-01

    We present a simple influence function based approach to compute the variances of estimates of absolute risk and functions of absolute risk. We apply this approach to criteria that assess the impact of changes in the risk factor distribution on absolute risk for an individual and at the population level. As an illustration we use an absolute risk prediction model for breast cancer that includes modifiable risk factors in addition to standard breast cancer risk factors. Influence function based variance estimates for absolute risk and the criteria are compared to bootstrap variance estimates. PMID:21643476

  13. Electron-impact excitation cross sections for the b /sup 3/. sigma. /sub u//sup +/ state of H/sub 2/

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khakoo, M.A.; Trajmar, S.; McAdams, R.

    1987-04-01

    Differential and integral cross sections for electron-impact excitation of the b /sup 3/..sigma../sub u//sup +/ state of H/sub 2/ have been determined in the 20--100-eV impact energy region. The calibration of the cross sections was achieved through the H/sub 2/ elastic scattering cross sections, which in turn were normalized to absolute He elastic scattering cross sections. Comparison is made with available experimental data and with theoretical results applying Born-Ochkur-Rudge, distorted-wave, and close-coupling approximations.

  14. Electron impact excitation of coronene

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khakoo, M.A.; Ratliff, J.M.; Trajmar, S.

    1990-12-15

    A preliminary study of the electron-impact excitation of thermally evaporated coronene at 550{degree} C was carried out using electron-energy-loss spectroscopy. Measurements of the energy-loss spectra of coronene at high (100 eV) and low (5--20 eV) impact energies are presented. One of the high-energy spectra was converted to an apparent generalized oscillator strength spectrum and compared to the photoabsorption spectrum of coronene. Observations concerning vibrational excitation of coronene by electron impact are also presented and discussed.

  15. Absolute laser-intensity measurement and online monitor calibration using a calorimeter at a soft X-ray free-electron laser beamline in SACLA

    NASA Astrophysics Data System (ADS)

    Tanaka, Takahiro; Kato, Masahiro; Saito, Norio; Owada, Shigeki; Tono, Kensuke; Yabashi, Makina; Ishikawa, Tetsuya

    2018-06-01

    This paper reports measurement of the absolute intensity of free-electron laser (FEL) and calibration of online intensity monitors for a brand-new FEL beamline BL1 at SPring-8 Angstrom Compact free-electron LAser (SACLA) in Japan. To measure the absolute intensity of FEL, we used a room-temperature calorimeter originally developed for FELs in the hard X-ray range. By using the calorimeter, we calibrated online intensity monitors of BL1, gas monitors (GMs), based on the photoionization of argon gas, in the photon energy range from 25 eV to 150 eV. A good correlation between signals obtained from the calorimeter and GMs was observed in the pulse energy range from 1 μJ to 100 μJ, where the upper limit is nearly equal to the maximum pulse energy at BL1. Moreover, the calibration result of the GMs, measured in terms of the spectral responsivity, demonstrates a characteristic photon-energy dependence owing to the occurrence of the Cooper minimum in the total ionization cross-section of argon gas. These results validate the feasibility of employing the room-temperature calorimeter in the measurement of absolute intensity of FELs over the specified photon energy range.

  16. Cross sections for direct and dissociative ionization of NH3 and CS2 by electron impact

    NASA Technical Reports Server (NTRS)

    Rao, M. V. V. S.; Srivastava, S. K.

    1991-01-01

    A crossed electron beam-molecular beam collision geometry is used to measure cross sections for the production of positive ions by electron impact on NH3 and CS2. Ionization cross-section data for NH3 and the values of various cross sections are presented, as well as ionization efficiency curves for CS2. Considerable differences are found between the various results on NH3. The present values are close to the data of Djuric et al. (1981). The semiempirical calculations of Hare and Meath (1987) differ considerably in the absolute values of cross sections. Discrepancies were observed in comparisons of cross sections of other fragment ions resulting from the ionization and dissociate ionization of NH3.

  17. Absolute dose determination in high-energy electron beams: Comparison of IAEA dosimetry protocols

    PubMed Central

    Sathiyan, S.; Ravikumar, M.

    2008-01-01

    In this study, absorbed doses were measured and compared for high-energy electrons (6, 9, 12, 16, and 20 MeV) using International Atomic Energy Agency (IAEA), Technical Reports Series No. 277 (TRS), TRS 381, and TRS 398 dosimetry protocols. Absolute dose measurements were carried out using FC65-G Farmer chamber and Nordic Association of Clinical Physicists (NACP) parallel plate chamber with DOSE1 electrometer in WP1-D water phantom for reference field size of 15 × 15 cm2 at 100 cm source-to-surface distance. The results show that the difference between TRS 398 and TRS 381 was about 0.24% to 1.3% depending upon the energy, and the maximum difference between TRS 398 and TRS 277 was 1.5%. The use of cylindrical chamber in electron beam gives the maximum dose difference between the TRS 398 and TRS 277 in the order of 1.4% for energies above 10 MeV (R50 > 4 g/cm2). It was observed that the accuracy of dose estimation was better with the protocols based on the water calibration procedures, as no conversion quantities are involved for conversion of dose from air to water. The cross-calibration procedure of parallel plate chamber with high-energy electron beams is recommended as it avoids pwall correction factor entering into the determination of kQ,Qo. PMID:19893700

  18. Electron Impact Ionization Cross Sections in Rb and Cs.

    NASA Astrophysics Data System (ADS)

    Reddish, T. J.; Lukomski, M.; Sutton, S.; Kedzierski, W.; McConkey, J. W.; Bartschat, K.; Bartlett, P. L.; Stelbovics, A. T.; Bray, I.

    2006-05-01

    We present a new atom trapping technique for determining absolute, total ionisation cross sections (TICS) out of an excited atom. The novel feature of this method is in utilizing Doppler cooling of neutral atoms to determine ionisation cross sections. This fluorescence-monitoring experiment, which is a variant of the `trap loss' technique, has enabled us to obtain the experimental electron impact ionisation cross sections out of the Cs 6^2P3/2 excited state between 7 - 400 eV. New CCC, R-Matrix with Pseudo-States (RMPS), and Born approximation single ionisation cross sections (SICS) are also presented for both the ground and excited states of Cs and Rb, and compared with the available experimental data. The comparison of the results reveals the importance of the autoionisation and multiple ionisation contributions to the TICS. The autoionisation contribution appears to be substantial for ionisation out of the Cs 6^2P and Rb 5^2P excited states; ˜ 3-4 larger than the direct ionisation contribution predicted by CCC at ˜ 30-50 eV. This surprising result shows the importance of multi-electron processes in determining the ionisation cross sections of heavy alkali atoms.

  19. Excitation of the Werner bands of H2 by electron impact

    NASA Technical Reports Server (NTRS)

    Stone, E. J.; Zipf, E. C.

    1972-01-01

    Absolute cross sections for the excitation of the H2 Werner band system were measured from energy threshold to 300 eV for electron impact on H2. The bands were observed in emission in the wavelength region 1100A to 1250A. The measured cross sections were compared with published transition probabilities, leading to the conclusion that the Werner bands are suitable as the basis for a relative spectral response calibration only when the bands are observed under sufficiently high resolution. The effect of the perturbation between the C 1Pi u and B 1 Sigma-u states of the hydrogen molecule was clearly observed in anomalies in the rotational intensity distribution in bands of the (3 v '') progression.

  20. Electronic excitation of carbonyl sulphide (COS) by high-resolution vacuum ultraviolet photoabsorption and electron-impact spectroscopy in the energy region from 4 to 11 eV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Limão-Vieira, P., E-mail: plimaovieira@fct.unl.pt; Department of Physics, Sophia University, Tokyo 102-8554; Department of Physical Sciences, The Open University, Walton Hall, Milton Keynes MK7 6AA

    2015-02-14

    The electronic state spectroscopy of carbonyl sulphide, COS, has been investigated using high resolution vacuum ultraviolet photoabsorption spectroscopy and electron energy loss spectroscopy in the energy range of 4.0–10.8 eV. The spectrum reveals several new features not previously reported in the literature. Vibronic structure has been observed, notably in the low energy absorption dipole forbidden band assigned to the (4π←3π) ({sup 1}Δ←{sup 1}Σ{sup +}) transition, with a new weak transition assigned to ({sup 1}Σ{sup −}←{sup 1}Σ{sup +}) reported here for the first time. The absolute optical oscillator strengths are determined for ground state to {sup 1}Σ{sup +} and {sup 1}Πmore » transitions. Based on our recent measurements of differential cross sections for the optically allowed ({sup 1}Σ{sup +} and {sup 1}Π) transitions of COS by electron impact, the optical oscillator strength f{sub 0} value and integral cross sections (ICSs) are derived by applying a generalized oscillator strength analysis. Subsequently, ICSs predicted by the scaling are confirmed down to 60 eV in the intermediate energy region. The measured absolute photoabsorption cross sections have been used to calculate the photolysis lifetime of carbonyl sulphide in the upper stratosphere (20–50 km)« less

  1. Absolute cascade-free cross-sections for the 2S to 2P transition in Zn(+) using electron-energy-loss and merged-beams methods

    NASA Technical Reports Server (NTRS)

    Smith, Steven J.; Man, K.-F.; Chutjian, A.; Mawhorter, R. J.; Williams, I. D.

    1991-01-01

    Absolute cascade-free excitation cross-sections in an ion have been measured for the resonance 2S to 2P transition in Zn(+) using electron-energy-loss and merged electron-ion beams methods. Measurements were carried out at electron energies of below threshold to 6 times threshold. Comparisons are made with 2-, 5-, and 15-state close-coupling and distorted-wave theories. There is good agreement between experiment and the 15-state close-coupling cross-sections over the energy range of the calculations.

  2. Differential electron emission from polycyclic aromatic hydrocarbon molecules under fast ion impact

    DOE PAGES

    Biswas, Shubhadeep; Champion, Christophe; Weck, P. F.; ...

    2017-07-17

    Interaction between polycyclic aromatic hydrocarbon (PAH) molecule and energetic ion is a subject of interest in different areas of modern physics. Here, we present measurements of energy and angular distributions of absolute double differential electron emission cross section for coronene (C 24H 12) and fluorene (C 13H 10) molecules under fast bare oxygen ion impact. For coronene, the angular distributions of the low energy electrons are quite different from that of simpler targets like Ne or CH 4, which is not the case for fluorene. The behaviour of the higher electron energy distributions for both the targets are similar tomore » that for simple targets. In case of coronene, a clear signature of plasmon resonance is observed in the analysis of forward-backward angular asymmetry of low energy electron emission. For fluorene, such signature is not identified probably due to lower oscillator strength of plasmon compared to the coronene. The theoretical calculation based on the first-order Born approximation with correct boundary conditions (CB1), in general, reproduced the experimental observations qualitatively, for both the molecules, except in the low energy region for coronene, which again indicates the role of collective excitation. Single differential and total cross sections are also deduced. An overall comparative study is presented.« less

  3. Total cross sections for electron scattering by 1-propanol at impact energies in the range 40-500 eV

    NASA Astrophysics Data System (ADS)

    da Silva, D. G. M.; Gomes, M.; Ghosh, S.; Silva, I. F. L.; Pires, W. A. D.; Jones, D. B.; Blanco, F.; Garcia, G.; Buckman, S. J.; Brunger, M. J.; Lopes, M. C. A.

    2017-11-01

    Absolute total cross section (TCS) measurements for electron scattering from 1-propanol molecules are reported for impact energies from 40 to 500 eV. These measurements were obtained using a new apparatus developed at Juiz de Fora Federal University—Brazil, which is based on the measurement of the attenuation of a collimated electron beam through a gas cell containing the molecules to be studied at a given pressure. Besides these experimental measurements, we have also calculated TCS using the Independent-Atom Model with Screening Corrected Additivity Rule and Interference (IAM-SCAR+I) approach with the level of agreement between them being typically found to be very good.

  4. Design of Stretchable Electronics Against Impact.

    PubMed

    Yuan, J H; Pharr, M; Feng, X; Rogers, John A; Huang, Yonggang

    2016-10-01

    Stretchable electronics offer soft, biocompatible mechanical properties; these same properties make them susceptible to device failure associated with physical impact. This paper studies designs for stretchable electronics that resist failure from impacts due to incorporation of a viscoelastic encapsulation layer. Results indicate that the impact resistance depends on the thickness and viscoelastic properties of the encapsulation layer, as well as the duration of impact. An analytic model for the critical thickness of the encapsulation layer is established. It is shown that a commercially available, low modulus silicone material offers viscous properties that make it a good candidate as the encapsulation layer for stretchable electronics.

  5. Electron-impact excitation of He: Dependence of electron-photon coherence parameters on the principal quantum number

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hammond, P.; Khakoo, M.A.; McConkey, J.W.

    1987-12-01

    Measurements are presented representing a complete set of electron-photon polarization correlation parameters for the excitation of n /sup 1/P states of He at an incident energy of 80 eV and an electron scattering angle of 20/sup 0/. The data support the predictions of a recent theoretical paper that these parameters should exhibit little variation with n. However, disagreement in absolute values between experiment and theory indicates the need for additional theoretical input into the problem.

  6. Effective and absolute cross sections for low-energy (1-30 eV) electron interactions with condensed biomolecules

    NASA Astrophysics Data System (ADS)

    Zheng, Yi; Sanche, Léon

    2018-06-01

    Ionizing radiation is intensively used for therapeutic [e.g., radiotherapy, brachytherapy, and targeted radionuclide therapy (TRT)], as well as for diagnostic medical imaging purposes. In these applications, the radiation dose given to the patient should be known and controlled. In conventional cancer treatments, absorbed dose calculations rely essentially on scattering cross sections (CSs) of the primary high-energy radiation. In more sophisticated treatments, such as combined radio- and chemo-therapy, a description of the details of energy deposits at the micro- and nano-scopic level is preferred to relate dose to radiobiological effectiveness or to evaluate doses at the biomolecular level, when radiopharmaceuticals emitting short-range radiation are delivered to critical molecular components of cancer cells (e.g., TRT). These highly radiotoxic compounds emit large densities of low-energy electrons (LEEs). More generally, LEE (0-30 eV) are emitted in large numbers by any type of high-energy radiation; i.e., about 30 000 per MeV of deposited primary energy. Thus, to optimize the effectiveness of several types of radiation treatments, the energy deposited by LEEs must be known at the level of the cell, nucleus, chromosome, or DNA. Such local doses can be evaluated by Monte Carlo (MC) calculations, which account event-by-event, for the slowing down of all generations of particles. In particular, these codes require as input parameters absolute LEE CSs for elastic scattering, energy losses, and direct damage to vital cellular molecules, particularly DNA, the main target of radiation therapy. In the last decade, such CSs have emerged in the literature. Furthermore, a method was developed to transform relative yields of damages into absolute CSs by measuring specific parameters in the experiments. In this review article, we first present a general description of dose calculations in biological media via MC simulation and give an overview of the CSs available from

  7. Directly relating gas-phase cluster measurements to solution-phase hydrolysis, the absolute standard hydrogen electrode potential, and the absolute proton solvation energy.

    PubMed

    Donald, William A; Leib, Ryan D; O'Brien, Jeremy T; Williams, Evan R

    2009-06-08

    Solution-phase, half-cell potentials are measured relative to other half-cell potentials, resulting in a thermochemical ladder that is anchored to the standard hydrogen electrode (SHE), which is assigned an arbitrary value of 0 V. A new method for measuring the absolute SHE potential is demonstrated in which gaseous nanodrops containing divalent alkaline-earth or transition-metal ions are reduced by thermally generated electrons. Energies for the reactions 1) M(H(2)O)(24)(2+)(g) + e(-)(g)-->M(H(2)O)(24)(+)(g) and 2) M(H(2)O)(24)(2+)(g) + e(-)(g)-->MOH(H(2)O)(23)(+)(g) + H(g) and the hydrogen atom affinities of MOH(H(2)O)(23)(+)(g) are obtained from the number of water molecules lost through each pathway. From these measurements on clusters containing nine different metal ions and known thermochemical values that include solution hydrolysis energies, an average absolute SHE potential of +4.29 V vs. e(-)(g) (standard deviation of 0.02 V) and a real proton solvation free energy of -265 kcal mol(-1) are obtained. With this method, the absolute SHE potential can be obtained from a one-electron reduction of nanodrops containing divalent ions that are not observed to undergo one-electron reduction in aqueous solution.

  8. Directly Relating Gas-Phase Cluster Measurements to Solution-Phase Hydrolysis, the Absolute Standard Hydrogen Electrode Potential, and the Absolute Proton Solvation Energy

    PubMed Central

    Donald, William A.; Leib, Ryan D.; O’Brien, Jeremy T.; Williams, Evan R.

    2009-01-01

    Solution-phase, half-cell potentials are measured relative to other half-cell potentials, resulting in a thermochemical ladder that is anchored to the standard hydrogen electrode (SHE), which is assigned an arbitrary value of 0 V. A new method for measuring the absolute SHE potential is demonstrated in which gaseous nanodrops containing divalent alkaline-earth or transition-metal ions are reduced by thermally generated electrons. Energies for the reactions 1) M-(H2O)242+(g)+e−(g)→M(H2O)24+(g) and 2) M(H2O)242+(g)+e−(g)→MOH(H2O)23+(g)+H(g) and the hydrogen atom affinities of MOH(H2O)23+(g) are obtained from the number of water molecules lost through each pathway. From these measurements on clusters containing nine different metal ions and known thermochemical values that include solution hydrolysis energies, an average absolute SHE potential of +4.29 V vs. e−(g) (standard deviation of 0.02 V) and a real proton solvation free energy of −265 kcal mol−1 are obtained. With this method, the absolute SHE potential can be obtained from a one-electron reduction of nanodrops containing divalent ions that are not observed to undergo one-electron reduction in aqueous solution. PMID:19440999

  9. Electronic Excitation of Furan by Low Energy Electrons

    NASA Astrophysics Data System (ADS)

    Hargreaves, Leigh R.; Khakoo, Murtadha A.; Lopes, Maria Cristina A.; da Costa, Romarly; Bettega, Marcio H. F.; Lima, Marco A. P.

    2011-10-01

    We present absolute differential cross section (DCS) measurements and calculations of electron impact excitation of the lowest lying triplet 3B2 and 3A1 electronic states of furan. The incident electron energy range of the present study was 5-15eV. The experimental data were normalized to the elastic DCS data of. The cross sections were determined by unfolding electron energy loss spectra, using an open source data analysis package and the spectroscopic assignments of. The calculations employ a Multichannel Schwinger method with a 9-state closed coupling CI configuration including polarized pseudo-potentials. The preliminary theoretical results show reasonable agreement with experiment below 10eV, but differ at higher energies. Funded by the US NSF and the Brazilian funding agencies CNPq, CAPES and FAPESP.

  10. Electron Impact Excitation-Ionization of Molecules

    NASA Astrophysics Data System (ADS)

    Ali, Esam Abobakr A.

    In the last few decades, the study of atomic collisions by electron-impact has made significant advances. The most difficult case to study is electron impact ionization of molecules for which many approximations have to be made and the validity of these approximations can only be checked by comparing with experiment. In this thesis, I have examined the Molecular three-body distorted wave (M3DW) or Molecular four-body distorted wave (M4DW) approximations for electron-impact ionization. These models use a fully quantum mechanical approach where all particles are treated quantum mechanically and the post collision interaction (PCI) is treated to all orders of perturbation. These electron impact ionization collisions play central roles in the physics and chemistry of upper atmosphere, biofuel, the operation of discharges and lasers, radiation induced damage in biological material like damage to DNA by secondary electrons, and plasma etching processes. For the M3DW model, I will present results for electron impact single ionization of small molecules such as Water, Ethane, and Carbon Dioxide and the much larger molecules Tetrahydrofuran, phenol, furfural, 1-4 Benzoquinone. I will also present results for the four-body problem in which there are two target electrons involved in the collision. M4DW results will be presented for dissociative excitation-ionization of orientated D2. I will show that M4DW calculations using a variational wave function for the ground state that included s- and p- orbital states give better agreement to the experimental measurements than a ground state approximated as a product of two 1s-type Dyson orbitals.

  11. Measurement of inelastic cross sections for low-energy electron scattering from DNA bases.

    PubMed

    Michaud, Marc; Bazin, Marc; Sanche, Léon

    2012-01-01

    To determine experimentally the absolute cross sections (CS) to deposit various amount of energies into DNA bases by low-energy electron (LEE) impact. Electron energy loss (EEL) spectra of DNA bases were recorded for different LEE impact energies on the molecules deposited at very low coverage on an inert argon (Ar) substrate. Following their normalisation to the effective incident electron current and molecular surface number density, the EEL spectra were then fitted with multiple Gaussian functions in order to delimit the various excitation energy regions. The CS to excite a molecule into its various excitation modes were finally obtained from computing the area under the corresponding Gaussians. The EEL spectra and absolute CS for the electronic excitations of pyrimidine and the DNA bases thymine, adenine, and cytosine by electron impacts below 18 eV were reported for the molecules deposited at about monolayer coverage on a solid Ar substrate. The CS for electronic excitations of DNA bases by LEE impact were found to lie within the 10(216) to 10(218) cm(2) range. The large value of the total ionisation CS indicated that ionisation of DNA bases by LEE is an important dissipative process via which ionising radiation degrades and is absorbed in DNA.

  12. Measurement of inelastic cross sections for low-energy electron scattering from DNA bases

    PubMed Central

    Michaud, Marc; Bazin, Marc.; Sanche, Léon

    2013-01-01

    Purpose Determine experimentally the absolute cross sections (CS) to deposit various amount of energies into DNA bases by low-energy electron (LEE) impact. Materials and methods Electron energy loss (EEL) spectra of DNA bases are recorded for different LEE impact energies on the molecules deposited at very low coverage on an inert argon (Ar) substrate. Following their normalisation to the effective incident electron current and molecular surface number density, the EEL spectra are then fitted with multiple Gaussian functions in order to delimit the various excitation energy regions. The CS to excite a molecule into its various excitation modes are finally obtained from computing the area under the corresponding Gaussians. Results The EEL spectra and absolute CS for the electronic excitations of pyrimidine and the DNA bases thymine, adenine, and cytosine by electron impacts below 18 eV are reported for the molecules deposited at about monolayer coverage on a solid Ar substrate. Conclusions The CS for electronic excitations of DNA bases by LEE impact are found to lie within the 10−16 – 10−18 cm2 range. The large value of the total ionisation CS indicates that ionisation of DNA bases by LEE is an important dissipative process via which ionising radiation degrades and is absorbed in DNA. PMID:21615242

  13. Flux trapping in multi-loop SQUIDs and its impact on SQUID-based absolute magnetometry

    NASA Astrophysics Data System (ADS)

    Schönau, T.; Zakosarenko, V.; Schmelz, M.; Anders, S.; Meyer, H.-G.; Stolz, R.

    2018-07-01

    The effect of flux trapping on the flux-voltage characteristics of multi-loop SQUID magnetometers was investigated by means of repeated cool-down cycles in a stepwise increased magnetic background field. For a SQUID with N parallel loops, N different flux offsets, each separated by {{{Φ }}}0/N, were observed even in zero magnetic field. These flux offsets further split into a so called fine structure, which can be explained by minor asymmetries in the SQUID design. The observed results are discussed with particular regard to their impact on the previously presented absolute SQUID cascade vector magnetometer.

  14. Isomer and Fluorination Effects among Fluorine Substituted Hydrocarbon C3/C4 Molecules in Electron Impact Ionization

    NASA Astrophysics Data System (ADS)

    Patel, U. R.; Joshipura, K. N.

    2015-05-01

    Electron collision processes are very important in both man-made and natural plasmas, for determining the energy balances and transport properties of electrons. Electron -molecule scattering leading to ionization represents one of the most fundamental processes in collision physics. In the gas phase, the total efficiency of the process is described by the absolute total electron impact ionization cross section. Carbon based materials are some of the widely used materials for a divertor plate and magnetically confined fusion devices. In the ``ITER,'' it is very important for steady state operation to have an estimate of the lifetime of carbon plasma facing components. Apart from fusion plasma relevance, the present theoretical study is very important in modeling and controlling other electron assisted processes in many areas. Hydrocarbons play an important role for plasma diagnostics as impurities in the Tokamak fusion divertor, as seed gases for the production of radicals and ions in low temperature plasma processing. Fluorine substituted hydrocarbons (perfluorocarbons) are important as reactants in plasma assisted fabrication processes. In the present work, we have calculated total ionization cross sections Qion for C3/C4 Hydrocarbon isomers by electron impact, and comparisons are made mutually to observe isomer effect. Comparisons are also made by substituting H atom by F atom and revealing fluorination effect. The present calculations are quite significant owing to the lack of experimental data, with just an isolated previous theoretical work in some cases.

  15. Electron-Impact Ionization Cross Section Database

    National Institute of Standards and Technology Data Gateway

    SRD 107 Electron-Impact Ionization Cross Section Database (Web, free access)   This is a database primarily of total ionization cross sections of molecules by electron impact. The database also includes cross sections for a small number of atoms and energy distributions of ejected electrons for H, He, and H2. The cross sections were calculated using the Binary-Encounter-Bethe (BEB) model, which combines the Mott cross section with the high-incident energy behavior of the Bethe cross section. Selected experimental data are included.

  16. Electron impact excitation of the electronic states of N2. III - Transitions in the 12.5-14.2-eV energy-loss region at incident energies of 40 and 60 eV

    NASA Technical Reports Server (NTRS)

    Chutjian, A.; Trajmar, S.; Cartwright, D. C.

    1977-01-01

    Analysis of electron energy-loss data at incident electron energies of 40 and 60 eV has led to the determination of normalized absolute differential cross sections for electron-impact excitation of five optically-allowed singlet states, two known triplet states, and two unknown triplet-like states of N2, lying in the energy-loss range 12.5-14.2 eV. The range of scattering angles was 5 to 138 deg. The optically allowed transitions and the known triplet excitations are identified. Cross sections for excitation to two unidentified triplet-like states at 13.155 and 13.395 eV were also obtained. The relationship of the generalized oscillator strength for the dipole-allowed states obtained from the described data to known optical oscillator strengths is discussed.

  17. Metastable Oxygen Production by Electron-Impact of Oxygen

    NASA Astrophysics Data System (ADS)

    Hein, Jeffrey; Johnson, Paul; Kanik, Isik; Malone, Charles

    2014-05-01

    Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of atomic O and molecular O2 play a significant role in the dynamics of oxygen-containing atmospheres (Earth, Europa, Io). Emissions from metastable O (1S --> 1D) produce the well-recognized green light from terrestrial aurora. Electron-impact excitation to 1S and 1D are sensitive channels for determining energy partitioning and dynamics from space weather. Electron-impact excitation cross sections determined through fundamental experimental studies are necessary for modeling of natural phenomena and observation data. The detection of metastable states in laboratory experiments requires a novel approach, since typical detection techniques (e.g., fluorescence by radiative de-excitation) cannot be performed due to the long-lived nature of the excited species. In this work, metastable O is produced through electron impact, and is incident on a cryogenically cooled rare gas matrix. The excimer production and subsequent rapid radiative de-excitation provides measurable signal that is directly related to the originating electron-impact excitation process.

  18. Absolute empirical rate coefficient for the excitation of the 117.6 nm line in C III

    NASA Astrophysics Data System (ADS)

    Gardner, L. D.; Daw, A. N.; Janzen, P. H.; Atkins, N.; Kohl, J. L.

    2005-05-01

    We have measured the absolute cross sections for electron impact excitation (EIE) of C2+ (2s2p 3P° - 2p2 3P) for energies from below threshold to 17 eV above and derived EIE rate coefficients required for astrophysical applications. The uncertainty in the rate coefficient at a typical solar temperature of formation of C2+ is less than ± 6 %. Ions are produced in a 5 GHz Electron Cyclotron Resonance (ECR) ion source, extracted, formed into a beam, and transported to a collision chamber where they collide with electrons from an electron beam inclined at 45 degrees. The beams are modulated and the radiation from the decay of the excited ions at λ 117.6 nm is detected synchronously using an absolutely calibrated optical system that subtends slightly over π steradians. The fractional population of the C2+ metastable state in the incident ion beam has been determined experimentally to be 0.42 ± 0.03 (1.65 σ). At the reported ± 15 % total experimental uncertainty level (1.65 σ), the measured structure and absolute scale of the cross section are in fairly good agreement with 6-term close-coupling R-matrix calculations and 90-term R-matrix with pseudo-states calculations, although some minor differences are seen just above threshold. As density-sensitive line intensity ratios vary by only about a factor of 5 as the density changes by nearly a factor of 100, even a 30 % uncertainty in the excitation rate can lead to a factor of 3 error in density. This work is supported by NASA Supporting Research and Technology grants NAG5- 9516 and NAG5-12863 in Solar and Heliospheric Physics and by the Smithsonian Astrophysical Observatory.

  19. SU-F-T-492: The Impact of Water Temperature On Absolute Dose Calibration

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Islam, N; Podgorsak, M; Roswell Park Cancer Institute, Buffalo, NY

    Purpose: The Task Group 51 (TG 51) protocol prescribes that dose calibration of photon beams be done by irradiating an ionization chamber in a water tank at pre-defined depths. Methodologies are provided to account for variations in measurement conditions by applying correction factors. However, the protocol does not completely account for the impact of water temperature. It is well established that water temperature will influence the density of air in the ion chamber collecting volume. Water temperature, however, will also influence the size of the collecting volume via thermal expansion of the cavity wall and the density of the watermore » in the tank. In this work the overall effect of water temperature on absolute dosimetry has been investigated. Methods: Dose measurements were made using a Farmer-type ion chamber for 6 and 23 MV photon beams with water temperatures ranging from 10 to 40°C. A reference ion chamber was used to account for fluctuations in beam output between successive measurements. Results: For the same beam output, the dose determined using TG 51 was dependent on the temperature of the water in the tank. A linear regression of the data suggests that the dependence is statistically significant with p-values of the slope equal to 0.003 and 0.01 for 6 and 23 MV beams, respectively. For a 10 degree increase in water phantom temperature, the absolute dose determined with TG 51 increased by 0.27% and 0.31% for 6 and 23 MV beams, respectively. Conclusion: There is a measurable effect of water temperature on absolute dose calibration. To account for this effect, a reference temperature can be defined and a correction factor applied to account for deviations from this reference temperature during beam calibration. Such a factor is expected to be of similar magnitude to most of the existing TG 51 correction factors.« less

  20. Determination of absolute configuration of an isopimarane-type diterpenoid by experimental and theoretical electronic circular dichroism and vibrational circular dichroism

    NASA Astrophysics Data System (ADS)

    Wang, Zhi-Qiang; Wu, Cheng-Jun; Wang, Zhen-Hui; Huang, Chao; Huang, Jian; Wang, Jin-Hui; Sun, Tie-Min

    2017-10-01

    In this study, the stereochemistry of a new isopimarane-type diterpenoid isolated from the Callicarpa macrophylla Vahl, Callicapene M3, was studied by experimental electronic circular dichroism and vibrational circular dichroism with the aid of TDDFT theoretical calculations. The good consistence between the experimental and simulated circular dichroism has clearly confirmed the absolute configuration of the title compound as (4S, 5S, 9S, 10S, 13S, 14S)-14α-hydroxy-7,15-isopimaradien-18-oic acid.

  1. Metastable Oxygen Production by Electron-Impact of Oxygen

    NASA Astrophysics Data System (ADS)

    Hein, J. D.; Malone, C. P.; Kanik, I.; Johnson, P. V.

    2013-12-01

    Electron-impact excitation processes involving atomic and molecular oxygen are important in atmospheric interactions. The production of long-lived metastable O(1S) and O(1D) through electron impact of atomic O and molecular O2 play a significant role in the dynamics of oxygen-containing atmospheres (Earth, Europa, Io). Emissions from metastable O (1S → 1D) produce the well-recognized green light from terrestrial aurora. Electron-impact excitation to 1S and 1D are sensitive channels for determining energy partitioning and dynamics from space weather. Electron-impact excitation cross sections determined through fundamental experimental studies are necessary for modeling of natural phenomena and observation data. The detection of metastable states in laboratory experiments requires a novel approach, since typical detection techniques (e.g., fluorescence by radiative de-excitation) cannot be performed due to the long-lived nature of the excited species. In this work, metastable O is incident on a cryogenically cooled rare gas matrix, where excimer production and subsequent rapid radiative de-excitation provides measurable signal that is directly related to the originating electron-impact excitation process.

  2. Autoionizing resonances in electron-impact ionization of O5+ ions

    NASA Astrophysics Data System (ADS)

    Müller, A.; Teng, H.; Hofmann, G.; Phaneuf, R. A.; Salzborn, E.

    2000-12-01

    We report on a detailed experimental and theoretical study of electron-impact ionization of O5+ ions. A high-resolution scan measurement of the K-shell excitation threshold region has been performed with statistical uncertainties as low as 0.03%. At this level of precision a wealth of features in the cross section arising from indirect ionization processes becomes visible, and even interference of direct ionization with resonant-excitation/auto-double-ionization (READI) is clearly observed. The experimental results are compared with R-matrix calculations that include both direct and indirect processes in a unified way. Radiative damping of autoionizing Li-like states is found to be about 10-15 %. The calculations almost perfectly reproduce most of the experimental resonance features found in the present measurement including READI. They also agree with the direct-ionization converged close-coupling results of I. Bray [J. Phys. B 28, L247 (1995)] and the absolute total ionization cross section measurement of K. Rinn et al. [Phys. Rev. A 36, 595 (1987)].

  3. Evidence for Neutrals-Foreshock Electrons Impact at Mars

    NASA Astrophysics Data System (ADS)

    Mazelle, C. X.; Meziane, K.; Mitchell, D. L.; Garnier, P.; Espley, J. R.; Hamza, A. M.; Halekas, J.; Jakosky, B. M.

    2018-05-01

    Backstreaming electrons emanating from the bow shock of Mars reported from the Mars Atmosphere and Volatile EvolutioN/Solar Wind Electron Analyzer observations show a flux fall off with the distance from the shock. This feature is not observed at the terrestrial foreshock. The flux decay is observed only for electron energy E ≥ 29 eV. A reported recent study indicates that Mars foreshock electrons are produced at the shock in a mirror reflection of a portion of the solar wind electrons. In this context, and given that the electrons are sufficiently energetic to not be affected by the interplanetary magnetic field fluctuations, the observed flux decrease appears problematic. We investigate the possibility that the flux fall off with distance results from the impact of backstreaming electrons with Mars exospheric neutral hydrogen. We demonstrate that the flux fall off is consistent with the electron-atomic hydrogen impact cross section for a large range of energy. A better agreement is obtained for energy where the impact cross section is the highest. One important consequence is that foreshock electrons can play an important role in the production of pickup ions at Mars far exosphere.

  4. The impact of water temperature on the measurement of absolute dose

    NASA Astrophysics Data System (ADS)

    Islam, Naveed Mehdi

    To standardize reference dosimetry in radiation therapy, Task Group 51 (TG 51) of American Association of Physicist's in Medicine (AAPM) recommends that dose calibration measurements be made in a water tank at a depth of 10 cm and at a reference geometry. Methodologies are provided for calculating various correction factors to be applied in calculating the absolute dose. However the protocol does not specify the water temperature to be used. In practice, the temperature of water during dosimetry may vary considerably between independent sessions and different centers. In this work the effect of water temperature on absolute dosimetry has been investigated. Density of water varies with temperature, which in turn may impact the beam attenuation and scatter properties. Furthermore, due to thermal expansion or contraction air volume inside the chamber may change. All of these effects can result in a change in the measurement. Dosimetric measurements were made using a Farmer type ion chamber on a Varian Linear Accelerator for 6 MV and 23 MV photon energies for temperatures ranging from 10 to 40 °C. A thermal insulation was designed for the water tank in order to maintain relatively stable temperature over the duration of the experiment. Dose measured at higher temperatures were found to be consistently higher by a very small magnitude. Although the differences in dose were less than the uncertainty in each measurement, a linear regression of the data suggests that the trend is statistically significant with p-values of 0.002 and 0.013 for 6 and 23 MV beams respectively. For a 10 degree difference in water phantom temperatures, which is a realistic deviation across clinics, the final calculated reference dose can differ by 0.24% or more. To address this effect, first a reference temperature (e.g.22 °C) can be set as the standard; subsequently a correction factor can be implemented for deviations from this reference. Such a correction factor is expected to be of similar

  5. SU-F-T-76: Total Skin Electron Therapy: An-End-To-End Examination of the Absolute Dosimetry with a Rando Phantom

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Cui, G; Ha, J; Zhou, S

    Purpose: To examine and validate the absolute dose for total skin electron therapy (TSET) through an end-to-end test with a Rando phantom using optically stimulated luminescent dosimeters (OSLDs) and EBT3 radiochromic films. Methods: A Varian Trilogy linear accelerator equipped with the special procedure 6 MeV HDTSe- was used to perform TSET irradiations using a modified Stanford 6-dual-field technique. The absolute dose was calibrated using a Markus ion chamber at a reference depth of 1.3cm at 100 cm SSD with a field size of 36 × 36 cm at the isocenter in solid water slabs. The absolute dose was cross validatedmore » by a farmer ion chamber. Then the dose rate in the unit of cGy/Mu was calibrated using the Markus chamber at the treatment position. OSLDs were used to independently verify the dose using the calibrated dose rate. Finally, a patient treatment plan (200 cGy/cycle) was delivered in the QA mode to a Rando phantom, which had 16 pairs of OSLDs and EBT3 films taped onto its surface at different anatomical positions. The doses recorded were read out to validate the absolute dosimetry for TSET. Results: The OSLD measurements were within 7% agreement with the planned dose except the shoulder areas, where the doses recorded were 23% lower on average than those of the planned. The EBT3 film measurements were within 10% agreement with the planned dose except the shoulder and the scalp vertex areas, where the respective doses recorded were 18% and 14% lower on average than those of the planned. The OSLDs gave more consistent dose measurements than those of the EBT3 films. Conclusion: The absolute dosimetry for TSET was validated by an end-to-end test with a Rando phantom using the OSLDs and EBT3 films. The beam calibration and monitor unit calculations were confirmed.« less

  6. Population-based absolute risk estimation with survey data

    PubMed Central

    Kovalchik, Stephanie A.; Pfeiffer, Ruth M.

    2013-01-01

    Absolute risk is the probability that a cause-specific event occurs in a given time interval in the presence of competing events. We present methods to estimate population-based absolute risk from a complex survey cohort that can accommodate multiple exposure-specific competing risks. The hazard function for each event type consists of an individualized relative risk multiplied by a baseline hazard function, which is modeled nonparametrically or parametrically with a piecewise exponential model. An influence method is used to derive a Taylor-linearized variance estimate for the absolute risk estimates. We introduce novel measures of the cause-specific influences that can guide modeling choices for the competing event components of the model. To illustrate our methodology, we build and validate cause-specific absolute risk models for cardiovascular and cancer deaths using data from the National Health and Nutrition Examination Survey. Our applications demonstrate the usefulness of survey-based risk prediction models for predicting health outcomes and quantifying the potential impact of disease prevention programs at the population level. PMID:23686614

  7. Threshold law for electron-atom impact ionization

    NASA Technical Reports Server (NTRS)

    Temkin, A.

    1982-01-01

    A derivation of the explicit form of the threshold law for electron impact ionization of atoms is presented, based on the Coulomb-dipole theory. The important generalization is made of using a dipole function whose moment is the dipole moment formed by an inner electron and the nucleus. The result is a modulated quasi-linear law for the yield of positive ions which applies to positron-atom impact ionization.

  8. Excitation of the 6p7s {sup 3}P{sub 0,1} states of Pb atoms by electron impact: Differential and integrated cross sections

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Milisavljevic, S.; Rabasovic, M. S.; Sevic, D.

    2007-08-15

    Experimental measurements of electron impact excitation of the 6p7s {sup 3}P{sub 0,1} states of Pb atoms have been made at incident electron energies E{sub 0}=10, 20, 40, 60, 80, and 100 eV and scattering angles from 10 deg. to 150 deg. In addition, relativistic distorted-wave calculations have been carried out at these energies. The data obtained include the differential (DCS), integral (Q{sub I}), momentum transfer (Q{sub M}), and viscosity (Q{sub V}) cross sections. Absolute values for the differential cross sections have been obtained by normalizing the relative DCSs at 10 deg. to the experimental DCS values of [S. Milisavljevic, M.more » S. Rabasovic, D. Sevic, V. Pejcev, D. M. Filipovic, L. Sharma, R. Srivastava, A. D. Stauffer, and B. P. Marinkovic, Phys. Rev. A 75, 052713 (2007)]. The integrated cross sections were determined by numerical integration of the absolute DCSs. The experimental results have been compared with the corresponding calculations and good agreement is obtained.« less

  9. Electron-Impact Ionization and Dissociative Ionization of Biomolecules

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Chaban, Galina M.; Dateo, Christopher E.

    2006-01-01

    It is well recognized that secondary electrons play an important role in radiation damage to humans. Particularly important is the damage of DNA by electrons, potentially leading to mutagenesis. Molecular-level study of electron interaction with DNA provides information on the damage pathways and dominant mechanisms. Our study of electron-impact ionization of DNA fragments uses the improved binary-encounter dipole model and covers DNA bases, sugar phosphate backbone, and nucleotides. An additivity principle is observed. For example, the sum of the ionization cross sections of the separate deoxyribose and phosphate fragments is in close agreement with the C3(sup prime)- and C5 (sup prime)-deoxyribose-phospate cross sections, differing by less than 5%. Investigation of tandem double lesion initiated by electron-impact dissociative ionization of guanine, followed by proton reaction with the cytosine in the Watson-Crick pair, is currently being studied to see if tandem double lesion can be initiated by electron impact. Up to now only OH-induced tandem double lesion has been studied.

  10. Electron collisions with ethylene

    NASA Astrophysics Data System (ADS)

    Panajotovic, R.; Kitajima, M.; Tanaka, H.; Jelisavcic, M.; Lower, J.; Campbell, L.; Brunger, M. J.; Buckman, S. J.

    2003-04-01

    We have measured absolute elastic scattering and vibrational excitation cross sections for electron impact on ethylene. The experimental data have been obtained on two different crossed-beam electron spectrometers and they cover the energy range from 1 to 100 eV and scattering angles between 10° and 130°. Both differential (in angle) and energy-dependent cross sections have been measured. The differential cross sections have also been analysed using a molecular phase shift analysis technique in order to derive the integral elastic and elastic momentum transfer cross sections. Comparison is made with earlier data, where available, and also with a number of recent theoretical calculations.

  11. Impact of an electronic health record operating room management system in ophthalmology on documentation time, surgical volume, and staffing.

    PubMed

    Sanders, David S; Read-Brown, Sarah; Tu, Daniel C; Lambert, William E; Choi, Dongseok; Almario, Bella M; Yackel, Thomas R; Brown, Anna S; Chiang, Michael F

    2014-05-01

    Although electronic health record (EHR) systems have potential benefits, such as improved safety and quality of care, most ophthalmology practices in the United States have not adopted these systems. Concerns persist regarding potential negative impacts on clinical workflow. In particular, the impact of EHR operating room (OR) management systems on clinical efficiency in the ophthalmic surgery setting is unknown. To determine the impact of an EHR OR management system on intraoperative nursing documentation time, surgical volume, and staffing requirements. For documentation time and circulating nurses per procedure, a prospective cohort design was used between January 10, 2012, and January 10, 2013. For surgical volume and overall staffing requirements, a case series design was used between January 29, 2011, and January 28, 2013. This study involved ophthalmic OR nurses (n = 13) and surgeons (n = 25) at an academic medical center. Electronic health record OR management system implementation. (1) Documentation time (percentage of operating time documenting [POTD], absolute documentation time in minutes), (2) surgical volume (procedures/time), and (3) staffing requirements (full-time equivalents, circulating nurses/procedure). Outcomes were measured during a baseline period when paper documentation was used and during the early (first 3 months) and late (4-12 months) periods after EHR implementation. There was a worsening in total POTD in the early EHR period (83%) vs paper baseline (41%) (P < .001). This improved to baseline levels by the late EHR period (46%, P = .28), although POTD in the cataract group remained worse than at baseline (64%, P < .001). There was a worsening in absolute mean documentation time in the early EHR period (16.7 minutes) vs paper baseline (7.5 minutes) (P < .001). This improved in the late EHR period (9.2 minutes) but remained worse than in the paper baseline (P < .001). While cataract procedures required more

  12. Teaching Absolute Value Meaningfully

    ERIC Educational Resources Information Center

    Wade, Angela

    2012-01-01

    What is the meaning of absolute value? And why do teachers teach students how to solve absolute value equations? Absolute value is a concept introduced in first-year algebra and then reinforced in later courses. Various authors have suggested instructional methods for teaching absolute value to high school students (Wei 2005; Stallings-Roberts…

  13. Simulation of absolute amplitudes of ultrasound signals using equivalent circuits.

    PubMed

    Johansson, Jonny; Martinsson, Pär-Erik; Delsing, Jerker

    2007-10-01

    Equivalent circuits for piezoelectric devices and ultrasonic transmission media can be used to cosimulate electronics and ultrasound parts in simulators originally intended for electronics. To achieve efficient system-level optimization, it is important to simulate correct, absolute amplitude of the ultrasound signal in the system, as this determines the requirements on the electronics regarding dynamic range, circuit noise, and power consumption. This paper presents methods to achieve correct, absolute amplitude of an ultrasound signal in a simulation of a pulse-echo system using equivalent circuits. This is achieved by taking into consideration loss due to diffraction and the effect of the cable that connects the electronics and the piezoelectric transducer. The conductive loss in the transmission line that models the propagation media of the ultrasound pulse is used to model the loss due to diffraction. Results show that the simulated amplitude of the echo follows measured values well in both near and far fields, with an offset of about 10%. The use of a coaxial cable introduces inductance and capacitance that affect the amplitude of a received echo. Amplitude variations of 60% were observed when the cable length was varied between 0.07 m and 2.3 m, with simulations predicting similar variations. The high precision in the achieved results show that electronic design and system optimization can rely on system simulations alone. This will simplify the development of integrated electronics aimed at ultrasound systems.

  14. Structure elucidation and absolute stereochemistry of isomeric monoterpene chromane esters.

    PubMed

    Batista, João M; Batista, Andrea N L; Mota, Jonas S; Cass, Quezia B; Kato, Massuo J; Bolzani, Vanderlan S; Freedman, Teresa B; López, Silvia N; Furlan, Maysa; Nafie, Laurence A

    2011-04-15

    Six novel monoterpene chromane esters were isolated from the aerial parts of Peperomia obtusifolia (Piperaceae) using chiral chromatography. This is the first time that chiral chromane esters of this kind, ones with a tethered chiral terpene, have been isolated in nature. Due to their structural features, it is not currently possible to assess directly their absolute stereochemistry using any of the standard classical approaches, such as X-ray crystallography, NMR, optical rotation, or electronic circular dichroism (ECD). Herein we report the absolute configuration of these molecules, involving four chiral centers, using vibrational circular dichroism (VCD) and density functional theory (DFT) (B3LYP/6-31G*) calculations. This work further reinforces the capability of VCD to determine unambiguously the absolute configuration of structurally complex molecules in solution, without crystallization or derivatization, and demonstrates the sensitivity of VCD to specify the absolute configuration for just one among a number of chiral centers. We also demonstrate the sufficiency of using the so-called inexpensive basis set 6-31G* compared to the triple-ζ basis set TZVP for absolute configuration analysis of larger molecules using VCD. Overall, this work extends our knowledge of secondary metabolites in plants and provides a straightforward way to determine the absolute configuration of complex natural products involving a chiral parent moiety combined with a chiral terpene adduct.

  15. Extreme Ultraviolet Emission Spectrum of CO_2 Induced by Electron Impact at 200 eV

    NASA Technical Reports Server (NTRS)

    Kanik, I.; Ajello, J. M.; James, G. K.

    1993-01-01

    We present the extreme ultraviolet (EUV) emission spectrum of CO_2 induced by electronimpact at 200 eV. There are 36 spectral features which are identified with a resolution of 0.5 nmover the wavelength range of 40 to 125 nm. Absolute emission cross sections were obtained for eachof these features. The EUV emission spectrum induced by electron impact consist of atomicmultiplets of CI,II and OI,II,III as well as CO and CO^+ molecular band systems produced bydissociative excitation. The CI (119.4 nm) multiplet is the strongest feature of CI with a peak crosssection of 3.61 x 10^(-19) cm^2 at 200 eV. The strongest feature of OI in the EUV spectrum is theOI (99.0 nm) multiplet with a peak cross section of 3.59 x 10^(-19) cm^2 at 200 eV.

  16. Electron impact study of potassium hydroxide

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Trajmar, S.

    1979-01-01

    An attempt is made to measure the sum of the elastic, rotational and vibrational scattering of electrons by KOH at low impact energies (5 to 20 eV) at angles from 10 to 120 deg. Energy loss spectra taken in the 0 to 18 eV range using an electron impact spectrometer are used to identify the species contributing to electric scattering. At temperatures between 300 and 500 C, only inelastic spectral features belonging to water are detected, while at temperatures from 500 to 800 C strong atomic K lines, indicative of molecular dissociation, and H2 energy loss features become prominent. No features attributable to KOH, the KOH dimer, O2 or potassium oxides were observed, due to the effects of the dissociation products, and it is concluded that another technique will have to be developed in order to measure electron scattering by KOH.

  17. Electronic excitation of H{sub 2} by electron impact using soft norm-conserving pseudopotentials

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Natalense, A.P.; Sartori, C.S.; Ferreira, L.G.

    1996-12-01

    We calculate electronic excitation cross sections for the {ital b}{sup 3}{Sigma}{sup +}{sub {ital u}} {ital a}{sup 3}{Sigma}{sup +}{sub {ital g}} {ital c}{sup 3}{Pi}{sub {ital u}}, and {ital d}{sup 3}{Pi}{sub {ital u}} states of H{sub 2} by electron impact. Our results were obtained with the Schwinger multichannel method with pseudopotentials and real potentials at the two-channel level of approximation. Pseudo-H atoms are used to generate H{sub 2} molecules with almost the same low-energy spectrum as the real molecules. We show that the dynamics of the electronic excitation process of the pseudomolecules by electron impact is very similar to the real case.more » Our results support the idea that pseudopotentials can be used to obtain reliable molecular electronic excitation cross sections by low-energy electron impact, confirming the expectations of previous studies with CH{sub 2}O [Bettega {ital et} {ital al}., Phys. Rev. A {bold 25}, 1111 (1993)] and HBr [Rescigno, J. Chem. Phys. {bold 104}, 125 (1996)]. {copyright} {ital 1996 The American Physical Society.}« less

  18. Electron impact excitation of tin

    NASA Astrophysics Data System (ADS)

    Sharma, Lalita; Bharti, Swati; Srivastava, Rajesh

    2017-05-01

    We study the electron impact excitation of the fine-structure levels of the ground state configuration 5p2 to the excited states of the configuration 5p6s in tin atom. These calculations have been carried out in the jj coupling scheme using the relativistic distorted-wave method. Results for differential cross section are reported at incident electron energies 20, 50, 80 and 100 eV while integrated cross sections are presented in the incident electron energy range of 5 to 100 eV. Contribution to the Topical Issue: "Low-Energy Interactions related to Atmospheric and Extreme Conditions", edited by S. Ptasinska, M. Smialek-Telega, A. Milosavljevic and B. Sivaraman.

  19. Easy Absolute Values? Absolutely

    ERIC Educational Resources Information Center

    Taylor, Sharon E.; Mittag, Kathleen Cage

    2015-01-01

    The authors teach a problem-solving course for preservice middle-grades education majors that includes concepts dealing with absolute-value computations, equations, and inequalities. Many of these students like mathematics and plan to teach it, so they are adept at symbolic manipulations. Getting them to think differently about a concept that they…

  20. Improved absolute calibration of LOPES measurements and its impact on the comparison with REAS 3.11 and CoREAS simulations

    NASA Astrophysics Data System (ADS)

    Apel, W. D.; Arteaga-Velázquez, J. C.; Bähren, L.; Bekk, K.; Bertaina, M.; Biermann, P. L.; Blümer, J.; Bozdog, H.; Brancus, I. M.; Cantoni, E.; Chiavassa, A.; Daumiller, K.; de Souza, V.; Di Pierro, F.; Doll, P.; Engel, R.; Falcke, H.; Fuchs, B.; Gemmeke, H.; Grupen, C.; Haungs, A.; Heck, D.; Hiller, R.; Hörandel, J. R.; Horneffer, A.; Huber, D.; Huege, T.; Isar, P. G.; Kampert, K.-H.; Kang, D.; Krömer, O.; Kuijpers, J.; Link, K.; Łuczak, P.; Ludwig, M.; Mathes, H. J.; Melissas, M.; Morello, C.; Nehls, S.; Oehlschläger, J.; Palmieri, N.; Pierog, T.; Rautenberg, J.; Rebel, H.; Roth, M.; Rühle, C.; Saftoiu, A.; Schieler, H.; Schmidt, A.; Schoo, S.; Schröder, F. G.; Sima, O.; Toma, G.; Trinchero, G. C.; Weindl, A.; Wochele, J.; Zabierowski, J.; Zensus, J. A.

    2016-02-01

    LOPES was a digital antenna array detecting the radio emission of cosmic-ray air showers. The calibration of the absolute amplitude scale of the measurements was done using an external, commercial reference source, which emits a frequency comb with defined amplitudes. Recently, we obtained improved reference values by the manufacturer of the reference source, which significantly changed the absolute calibration of LOPES. We reanalyzed previously published LOPES measurements, studying the impact of the changed calibration. The main effect is an overall decrease of the LOPES amplitude scale by a factor of 2.6 ± 0.2, affecting all previously published values for measurements of the electric-field strength. This results in a major change in the conclusion of the paper 'Comparing LOPES measurements of air-shower radio emission with REAS 3.11 and CoREAS simulations' published by Apel et al. (2013) : With the revised calibration, LOPES measurements now are compatible with CoREAS simulations, but in tension with REAS 3.11 simulations. Since CoREAS is the latest version of the simulation code incorporating the current state of knowledge on the radio emission of air showers, this new result indicates that the absolute amplitude prediction of current simulations now is in agreement with experimental data.

  1. Absolutely relative or relatively absolute: violations of value invariance in human decision making.

    PubMed

    Teodorescu, Andrei R; Moran, Rani; Usher, Marius

    2016-02-01

    Making decisions based on relative rather than absolute information processing is tied to choice optimality via the accumulation of evidence differences and to canonical neural processing via accumulation of evidence ratios. These theoretical frameworks predict invariance of decision latencies to absolute intensities that maintain differences and ratios, respectively. While information about the absolute values of the choice alternatives is not necessary for choosing the best alternative, it may nevertheless hold valuable information about the context of the decision. To test the sensitivity of human decision making to absolute values, we manipulated the intensities of brightness stimuli pairs while preserving either their differences or their ratios. Although asked to choose the brighter alternative relative to the other, participants responded faster to higher absolute values. Thus, our results provide empirical evidence for human sensitivity to task irrelevant absolute values indicating a hard-wired mechanism that precedes executive control. Computational investigations of several modelling architectures reveal two alternative accounts for this phenomenon, which combine absolute and relative processing. One account involves accumulation of differences with activation dependent processing noise and the other emerges from accumulation of absolute values subject to the temporal dynamics of lateral inhibition. The potential adaptive role of such choice mechanisms is discussed.

  2. Dissociative-ionization cross sections for 12-keV-electron impact on CO{sub 2}

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bhatt, Pragya; Singh, Raj; Yadav, Namita

    The dissociative ionization of a CO{sub 2} molecule is studied at an electron energy of 12 keV using the multiple ion coincidence imaging technique. The absolute partial ionization cross sections and the precursor-specific absolute partial ionization cross sections of resulting fragment ions are obtained and reported. It is found that {approx}75% of single ionization, 22% of double ionization, and {approx}2% of triple ionization of the parent molecule contribute to the total fragment ion yield; quadruple ionization of CO{sub 2} is found to make a negligibly small contribution. Furthermore, the absolute partial ionization cross sections for ion-pair and ion-triple formation aremore » measured for nine dissociative ionization channels of up to a quadruply ionized CO{sub 2} molecule. In addition, the branching ratios for single-ion, ion-pair, and ion-triple formation are also determined.« less

  3. A novel double-focusing time-of-flight mass spectrometer for absolute recoil ion cross sections measurements.

    PubMed

    Sigaud, L; de Jesus, V L B; Ferreira, Natalia; Montenegro, E C

    2016-08-01

    In this work, the inclusion of an Einzel-like lens inside the time-of-flight drift tube of a standard mass spectrometer coupled to a gas cell-to study ionization of atoms and molecules by electron impact-is described. Both this lens and a conical collimator are responsible for further focalization of the ions and charged molecular fragments inside the spectrometer, allowing a much better resolution at the time-of-flight spectra, leading to a separation of a single mass-to-charge unit up to 100 a.m.u. The procedure to obtain the overall absolute efficiency of the spectrometer and micro-channel plate detector is also discussed.

  4. Electron impact excitation of the q{sup 1}S {r_arrow}n{sup 1}P (n=3,4) transitions in helium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khakoo, M.A.; Rugamas, F.; Roundy, D.

    1996-05-01

    Experimental differential cross-section (DCS) ratios for the above transitions to the 1{sup 1}S {r_arrow} 2{sup 1}P transition are reported at impact energies of 30eV, 40eV and 80eV and scattering angles in the range of 5{degrees} to 130{degrees}. The data are an extension of previously reported work using the electron-photon coincidence method in the VUV. The DCS ratios are normalized to available absolute DCSs for the 1{sup 1}S {r_arrow} 2{sup 1}P transition and the resulting n{sup 1}P DCSs are compared to previous semi-empirical DCSs as well as available theory.

  5. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1982-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  6. Absolute photoionization cross sections of atomic oxygen

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Pareek, P. N.

    1985-01-01

    The absolute values of photoionization cross sections of atomic oxygen were measured from the ionization threshold to 120 A. An auto-ionizing resonance belonging to the 2S2P4(4P)3P(3Do, 3So) transition was observed at 479.43 A and another line at 389.97 A. The experimental data is in excellent agreement with rigorous close-coupling calculations that include electron correlations in both the initial and final states.

  7. Electron scattering by highly polar molecules. II - LiF

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Srivastavas, S. K.; Trajmar, S.

    1978-01-01

    The crossed electron-beam - molecular-beam scattering technique has been used to measure relative values of differential 'elastic' scattering cross sections at electron impact energies of 5.4 and 20 eV for the angular range from 20 to 130 deg. The absolute values of these cross sections have been obtained by normalization to the classical perturbation theory of Dickinson (1977) at a scattering angle of 40 deg. These differential cross sections have then been used to calculate the integral and momentum-transfer cross sections. An energy-loss spectrum at 100 eV electron impact energy and 15 deg scattering angle has also been obtained. Two weak features at the energy losses of 6.74 and 8.82 eV appear. Their energy positions are compared with the recent calculations of Kahn et al. (1974).

  8. VUV dissociative excitation cross sections of H2O, NH3, and CH4 by electron impact. [Vacuum Ultra-Violet

    NASA Technical Reports Server (NTRS)

    Morgan, H. D.; Mentall, J. E.

    1974-01-01

    Absolute excitation functions for excited fragments resulting from electron bombardment of H2O, NH3, and CH4 by low-energy electrons (0 to 300 eV) have been measured in the vacuum ultraviolet (1100 to 1950 A). The predominant emission for each molecule was the H Lyman-alpha line, while the O I, N I, C I, and C II emissions were at least an order of magnitude weaker. Absolute cross sections at 100 eV are given along with the appearance potential of the various processes and the possible dissociative-excitation channels through which such processes proceed.

  9. Impact of the Absolute Difference in Diastolic Blood Pressure Between Arms in Patients With Coronary Artery Disease

    PubMed Central

    Hitaka, Yuka; Miura, Shin-ichiro; Koyoshi, Rie; Shiga, Yuhei; Miyase, Yuiko; Norimatsu, Kenji; Nakamura, Ayumi; Adachi, Sen; Kuwano, Takashi; Sugihara, Makoto; Ike, Amane; Nishikawa, Hiroaki; Saku, Keijiro

    2015-01-01

    Background We investigated the relationship between the severity and presence of coronary artery disease (CAD) and a difference in systolic and diastolic blood pressure (SBP and DBP) between arms or between lower limbs. Methods We enrolled 277 patients who underwent coronary angiography. We calculated the absolute (|right BP (rt. BP) - left BP (lt. BP)|) and relative (rt. BP - lt. BP) differences in SBP or DBP between arms or between lower limbs, and assessed the severity of CAD in terms of the Gensini score. Results The absolute difference in DBP between arms in the CAD group was significantly lower than that in the non-CAD group, whereas the absolute difference in DBP between lower limbs in the CAD group was significantly higher. There were no differences in the absolute or relative difference in SBP between arms or lower limbs between the groups. The absolute difference in DBP between arms decreased as the Gensini score increased. In a logistic regression analysis, the presence of CAD was independently associated with the absolute difference in DBP between arms, in addition to male, family history, dyslipidemia, diabetes mellitus and hypertension. Conclusion The absolute difference in DBP between arms in addition to traditional factors may be a critical risk factor for the presence of CAD. PMID:26491500

  10. Impact of the Absolute Difference in Diastolic Blood Pressure Between Arms in Patients With Coronary Artery Disease.

    PubMed

    Hitaka, Yuka; Miura, Shin-Ichiro; Koyoshi, Rie; Shiga, Yuhei; Miyase, Yuiko; Norimatsu, Kenji; Nakamura, Ayumi; Adachi, Sen; Kuwano, Takashi; Sugihara, Makoto; Ike, Amane; Nishikawa, Hiroaki; Saku, Keijiro

    2015-11-01

    We investigated the relationship between the severity and presence of coronary artery disease (CAD) and a difference in systolic and diastolic blood pressure (SBP and DBP) between arms or between lower limbs. We enrolled 277 patients who underwent coronary angiography. We calculated the absolute (|right BP (rt. BP) - left BP (lt. BP)|) and relative (rt. BP - lt. BP) differences in SBP or DBP between arms or between lower limbs, and assessed the severity of CAD in terms of the Gensini score. The absolute difference in DBP between arms in the CAD group was significantly lower than that in the non-CAD group, whereas the absolute difference in DBP between lower limbs in the CAD group was significantly higher. There were no differences in the absolute or relative difference in SBP between arms or lower limbs between the groups. The absolute difference in DBP between arms decreased as the Gensini score increased. In a logistic regression analysis, the presence of CAD was independently associated with the absolute difference in DBP between arms, in addition to male, family history, dyslipidemia, diabetes mellitus and hypertension. The absolute difference in DBP between arms in addition to traditional factors may be a critical risk factor for the presence of CAD.

  11. Absolute emission cross sections for electron capture reactions of C2+, N3+, N4+ and O3+ ions in collisions with Li(2s) atoms

    NASA Astrophysics Data System (ADS)

    Rieger, G.; Pinnington, E. H.; Ciubotariu, C.

    2000-12-01

    Absolute photon emission cross sections following electron capture reactions have been measured for C2+, N3+, N4+ and O3+ ions colliding with Li(2s) atoms at keV energies. The results are compared with calculations using the extended classical over-the-barrier model by Niehaus. We explore the limits of our experimental method and present a detailed discussion of experimental errors.

  12. Absolute biological needs.

    PubMed

    McLeod, Stephen

    2014-07-01

    Absolute needs (as against instrumental needs) are independent of the ends, goals and purposes of personal agents. Against the view that the only needs are instrumental needs, David Wiggins and Garrett Thomson have defended absolute needs on the grounds that the verb 'need' has instrumental and absolute senses. While remaining neutral about it, this article does not adopt that approach. Instead, it suggests that there are absolute biological needs. The absolute nature of these needs is defended by appeal to: their objectivity (as against mind-dependence); the universality of the phenomenon of needing across the plant and animal kingdoms; the impossibility that biological needs depend wholly upon the exercise of the abilities characteristic of personal agency; the contention that the possession of biological needs is prior to the possession of the abilities characteristic of personal agency. Finally, three philosophical usages of 'normative' are distinguished. On two of these, to describe a phenomenon or claim as 'normative' is to describe it as value-dependent. A description of a phenomenon or claim as 'normative' in the third sense does not entail such value-dependency, though it leaves open the possibility that value depends upon the phenomenon or upon the truth of the claim. It is argued that while survival needs (or claims about them) may well be normative in this third sense, they are normative in neither of the first two. Thus, the idea of absolute need is not inherently normative in either of the first two senses. © 2013 John Wiley & Sons Ltd.

  13. Electron- and positron-impact ionization of inert gases

    NASA Astrophysics Data System (ADS)

    Campeanu, R. I.; Walters, H. R. J.; Whelan, Colm T.

    2018-06-01

    Triple-differential cross sections (TDCS) are presented for the electron and positron impact ionization of inert gas atoms in a range of geometries where a number of significant few body effects compete to define the shape of the TDCS. Using both positrons and electrons as projectiles has opened up the possibility of performing complementary studies which could effectively isolate competing interactions which cannot be separately detected in an experiment with a single projectile. A comparison is presented between theory and the recent experiments of [Gavin, deLucio, and DuBois, Phys. Rev. A 95, 062703 (2017), 10.1103/PhysRevA.95.062703] for e± and contrasted with the results from earlier electron experiments. For the special case of xenon(5 p ), cross sections are presented for both electron- and positron-impact ionization in kinematics where the electron case appears well understood. The kinematics are then varied in order to focus on the possible role of distortion, exchange, and target wave-function effects.

  14. VUV Study of Electron-Pyrimidine Dissociative Excitation

    NASA Astrophysics Data System (ADS)

    Hein, Jeff; Al-Khazraji, Hajar; Tiessen, Collin; Lukic, Dragan; Trocchi, Joshuah; McConkey, William

    2013-05-01

    A crossed electron-gas beam system coupled to a VUV spectrometer has been used to investigate the dissociation of pyrimidine (C4H4N2) into excited atomic fragments in the electron-impact energy range from threshold to 375 eV. Data have been made absolute using Lyman- α from H2 as a secondary standard. The main features in the spectrum are the H Lyman series lines. The emission cross section of Lyman- α is measured to be (2.44 +/- 0.25) 10-18 cm2 at 100 eV impact energy. The probability of extracting C or N atoms from the ring is shown to be very small. Possible dissociation channels and excitation mechanisms in the parent molecule will be discussed. The authors thank NSERC (Canada) for financial support.

  15. Absolute Standard Hydrogen Electrode Potential Measured by Reduction of Aqueous Nanodrops in the Gas Phase

    PubMed Central

    Donald, William A.; Leib, Ryan D.; O'Brien, Jeremy T.; Bush, Matthew F.; Williams, Evan R.

    2008-01-01

    In solution, half-cell potentials are measured relative to those of other half cells, thereby establishing a ladder of thermochemical values that are referenced to the standard hydrogen electrode (SHE), which is arbitrarily assigned a value of exactly 0 V. Although there has been considerable interest in, and efforts toward, establishing an absolute electrochemical half-cell potential in solution, there is no general consensus regarding the best approach to obtain this value. Here, ion-electron recombination energies resulting from electron capture by gas-phase nanodrops containing individual [M(NH3)6]3+, M = Ru, Co, Os, Cr, and Ir, and Cu2+ ions are obtained from the number of water molecules that are lost from the reduced precursors. These experimental data combined with nanodrop solvation energies estimated from Born theory and solution-phase entropies estimated from limited experimental data provide absolute reduction energies for these redox couples in bulk aqueous solution. A key advantage of this approach is that solvent effects well past two solvent shells, that are difficult to model accurately, are included in these experimental measurements. By evaluating these data relative to known solution-phase reduction potentials, an absolute value for the SHE of 4.2 ± 0.4 V versus a free electron is obtained. Although not achieved here, the uncertainty of this method could potentially be reduced to below 0.1 V, making this an attractive method for establishing an absolute electrochemical scale that bridges solution and gas-phase redox chemistry. PMID:18288835

  16. Low-energy electron scattering from atomic hydrogen. I. Ionization

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Childers, J.G.; James, K.E. Jr.; Bray, Igor

    2004-02-01

    Absolute doubly differential cross sections for the ionization of atomic hydrogen by electron impact have been measured at energies ranging from near threshold to intermediate values. The measurements are normalized to the accurate differential cross section for the electron-impact excitation of the H 1 {sup 2}S{yields}2 {sup 2}S+2 {sup 2}P transition. These measurements were made possible through the use of a moveable target source which enables the collection of hydrogen energy loss spectra free of all backgrounds. The measurements cover the incident electron energy range of 14.6-40 eV and scattering angles from 12 deg. to 127 deg., and are inmore » very good agreement with the results of the latest theoretical models--the convergent close-coupling model and the exterior complex scaling model.« less

  17. Low-energy electron-impact single ionization of helium

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Colgan, J.; Pindzola, M. S.; Childers, G.

    2006-04-15

    A study is made of low-energy electron-impact single ionization of ground-state helium. The time-dependent close-coupling method is used to calculate total integral, single differential, double differential, and triple differential ionization cross sections for impact electron energies ranging from 32 to 45 eV. For all quantities, the calculated cross sections are found to be in very good agreement with experiment, and for the triple differential cross sections, good agreement is also found with calculations made using the convergent close-coupling technique.

  18. Electron impact excitation of carbon monoxide in comet Hale-Bopp

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.

    2009-02-01

    The fourth positive emissions of carbon monoxide in the coma of comet Hale-Bopp have been assumed to be due mainly to fluorescence induced by sunlight. Based on this assumption they were used to deduce the abundance of carbon monoxide in the comet, giving a value higher than in other comets. Emissions produced by electron impact excitation of CO were not considered. Recent measurements and theoretical calculations of integral cross sections for electron impact excitation of CO allow the contribution of electron impact to be calculated, giving about 40% of the total. This implies that the abundance of CO in the outer coma of comet Hale-Bopp was only 60% of that previously deduced. However, as the high proportion of CO in comet Hale-Bopp was also seen in some other measurements, alternative explanations are considered. The method of calculation is tested by successfully predicting the O I emission at 1356 Å, supporting the belief that this line is due to electron impact excitation.

  19. Sci-Sat AM: Radiation Dosimetry and Practical Therapy Solutions - 03: Energy dependence of a clinical probe-format calorimeter and its pertinence to absolute photon and electron beam dosimetry

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Renaud, James; Seuntjens, Jan; Sarfehnia, Arman

    Purpose: To evaluate the intrinsic and absorbed-dose energy dependence of a small-scale graphite calorimeter probe (GPC) developed for use as a routine clinical dosimeter. The influence of charge deposition on the response of the GPC was also assessed by performing absolute dosimetry in clinical linac-based electron beams. Methods: Intrinsic energy dependence was determined by performing constant-temperature calorimetry dose measurements in a water-equivalent solid phantom, under otherwise reference conditions, in five high-energy photon (63.5 < %dd(10){sub X} < 76.3), and five electron (2.3 cm < R{sub 50} < 8.3 cm) beams. Reference dosimetry was performed for all beams in question usingmore » an Exradin A19 ion chamber with a calibration traceable to national standards. The absorbed-dose component of the overall energy dependence was calculated using the EGSnrc egs-chamber user code. Results: A total of 72 measurements were performed with the GPC, resulting in a standard error on the mean absorbed dose of better than 0.3 % for all ten beams. For both the photon and electron beams, no statistically-significant energy dependence was observed experimentally. Peak-to-peak, variations in the relative response of the GPC across all beam qualities of a given radiation type were on the order of 1 %. No effects, either transient or permanent, were attributable to the charge deposited by the electron beams. Conclusions: The GPC’s apparent energy-independence, combined with its well-established linearity and dose rate independence, make it a potentially useful dosimetry system capable measuring photon and electron doses in absolute terms at the clinical level.« less

  20. Absolute Radiometric Calibration of EUNIS-06

    NASA Technical Reports Server (NTRS)

    Thomas, R. J.; Rabin, D. M.; Kent, B. J.; Paustian, W.

    2007-01-01

    The Extreme-Ultraviolet Normal-Incidence Spectrometer (EUNIS) is a soundingrocket payload that obtains imaged high-resolution spectra of individual solar features, providing information about the Sun's corona and upper transition region. Shortly after its successful initial flight last year, a complete end-to-end calibration was carried out to determine the instrument's absolute radiometric response over its Longwave bandpass of 300 - 370A. The measurements were done at the Rutherford-Appleton Laboratory (RAL) in England, using the same vacuum facility and EUV radiation source used in the pre-flight calibrations of both SOHO/CDS and Hinode/EIS, as well as in three post-flight calibrations of our SERTS sounding rocket payload, the precursor to EUNIS. The unique radiation source provided by the Physikalisch-Technische Bundesanstalt (PTB) had been calibrated to an absolute accuracy of 7% (l-sigma) at 12 wavelengths covering our bandpass directly against the Berlin electron storage ring BESSY, which is itself a primary radiometric source standard. Scans of the EUNIS aperture were made to determine the instrument's absolute spectral sensitivity to +- 25%, considering all sources of error, and demonstrate that EUNIS-06 was the most sensitive solar E W spectrometer yet flown. The results will be matched against prior calibrations which relied on combining measurements of individual optical components, and on comparisons with theoretically predicted 'insensitive' line ratios. Coordinated observations were made during the EUNIS-06 flight by SOHO/CDS and EIT that will allow re-calibrations of those instruments as well. In addition, future EUNIS flights will provide similar calibration updates for TRACE, Hinode/EIS, and STEREO/SECCHI/EUVI.

  1. Jasminum flexile flower absolute from India--a detailed comparison with three other jasmine absolutes.

    PubMed

    Braun, Norbert A; Kohlenberg, Birgit; Sim, Sherina; Meier, Manfred; Hammerschmidt, Franz-Josef

    2009-09-01

    Jasminum flexile flower absolute from the south of India and the corresponding vacuum headspace (VHS) sample of the absolute were analyzed using GC and GC-MS. Three other commercially available Indian jasmine absolutes from the species: J. sambac, J. officinale subsp. grandiflorum, and J. auriculatum and the respective VHS samples were used for comparison purposes. One hundred and twenty-one compounds were characterized in J. flexile flower absolute, with methyl linolate, benzyl salicylate, benzyl benzoate, (2E,6E)-farnesol, and benzyl acetate as the main constituents. A detailed olfactory evaluation was also performed.

  2. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-05-15

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  3. Absolute nuclear material assay

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2010-07-13

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  4. Absolute gravimetry as an operational tool for geodynamics research

    NASA Astrophysics Data System (ADS)

    Torge, W.

    Relative gravimetric techniques have been used for nearly 30 years for measuring non-tidal gravity variations with time, and thus have contributed to geodynamics research by monitoring vertical crustal movements and internal mass shifts. With today's accuracy of about ± 0.05µms-2 (or 5µGal), significant results have been obtained in numerous control nets of local extension, especially in connection with seismic and volcanic events. Nevertheless, the main drawbacks of relative gravimetry, which are deficiencies in absolute datum and calibration, set a limit for its application, especially with respect to large-scale networks and long-term investigations. These problems can now be successfully attacked by absolute gravimetry, with transportable gravimeters available since about 20 years. While the absolute technique during the first two centuries of gravimetry's history was based on the pendulum method, the free-fall method can now be employed taking advantage of laser-interferometry, electronic timing, vacuum and shock absorbing techniques, and on-line computer-control. The accuracy inherent in advanced instruments is about ± 0.05 µms-2. In field work, generally an accuracy of ±0.1 µms-2 may be expected, strongly depending on local environmental conditions.

  5. A rare gas optics-free absolute photon flux and energy analyzer to provide absolute photoionization rates of inflowing interstellar neutrals

    NASA Technical Reports Server (NTRS)

    Judge, Darrell L.

    1994-01-01

    A prototype spectrometer has been developed for space applications requiring long term absolute EUV photon flux measurements. The energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.

  6. Absolute detection efficiencies of low energy H, H -, H +, H 2+ and H 3+ incident on a multichannel plate detector

    NASA Astrophysics Data System (ADS)

    Peko, B. L.; Stephen, T. M.

    2000-12-01

    Measured absolute detection efficiencies are presented for H, H - and H n+ ( n=1,2,3) impacting a commercially available, dual multichannel plate (MCP) electron multiplier at kinetic energies ranging from 30 to 1000 eV. Measurements involving isotopic substitutions (D, D -, D n+) and Ar + are also presented. In addition, atomic hydrogen detection efficiencies relative to those of H + and H - are given, as they may have a more universal application. For the three charge states, H, H + and H -, the absolute detection efficiencies are markedly different at low energies and converge to a nearly uniform value of ˜70% with increasing projectile energy. The energy dependence is strongest for H +, varying nearly three orders of magnitude over the energy range studied, and weakest for H -, varying by less than one order of magnitude. In general, for the low energy positive ions at a given energy, the lighter the incident particle mass, the greater the probability of its detection.

  7. Electron-impact vibrational excitation of furan

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hargreaves, L. R.; Albaridy, R.; Serna, G.

    2011-12-15

    We report measurements of differential cross sections for the vibrational excitation of furan (C{sub 4}H{sub 4}O), obtaining results for nine features spanning the electron energy loss range from 0 to 0.8 eV, at electron-impact energies of 5, 6, 7.5, 10, and 15 eV and for scattering angles ranging from 10{sup o} to 130{sup o}. The normalization of the differential cross sections was done using elastic differential cross sections for furan determined earlier by our group [Khakoo et al., Phys. Rev A 81, 062716 (2010)].

  8. Plasma rate coefficients for electron-impact ionization of Xeq+ ions (q = 8, …, 17)

    NASA Astrophysics Data System (ADS)

    Borovik, A., Jr.; Gharaibeh, M. F.; Schippers, S.; Müller, A.

    2015-02-01

    Plasma rate coefficients (PRCs) for electron-impact single ionization of ground-state Xeq+ ions (q=8,\\ldots ,17) in the temperature range 2 × 105 - 2 × 107 K have been derived from a combination of experimental cross-section data and results of distorted-wave calculations. For Xe8+ and Xe9+ new measurements were performed and thoroughly analyzed with respect to the contributions from different ionization mechanisms and the effects of long-lived excited states in the parent ion beams that had been employed in the experiments. In the same manner, previously published experimental data for the higher charge states were analyzed to extract the ground-configuration ionization cross sections and to derive the associated PRCs. The resulting temperature-dependent PRC functions were parameterized and the associated parameters are provided in tabular form. With the exception of Xe8+ the absolute uncertainties of the inferred rate coefficients are estimated to be +/- 10%. For Xe8+ the uncertainties are +/- 25% due to the necessary correction for strong metastable-ion contributions to the measured cross sections.

  9. Electron-impact ionization cross sections out of the ground and 6P2 excited states of cesium

    NASA Astrophysics Data System (ADS)

    Łukomski, M.; Sutton, S.; Kedzierski, W.; Reddish, T. J.; Bartschat, K.; Bartlett, P. L.; Bray, I.; Stelbovics, A. T.; McConkey, J. W.

    2006-09-01

    An atom trapping technique for determining absolute, total ionization cross sections (TICS) out of an excited atom is presented. The unique feature of our method is in utilizing Doppler cooling of neutral atoms to determine ionization cross sections. This fluorescence-monitoring experiment, which is a variant of the “trap loss” technique, has enabled us to obtain the experimental electron impact ionization cross sections out of the Cs 6P3/22 state between 7eV and 400eV . CCC, RMPS, and Born theoretical results are also presented for both the ground and excited states of cesium and rubidium. In the low energy region (<11eV) where best agreement between these excited state measurements and theory might be expected, a discrepancy of approximately a factor of five is observed. Above this energy there are significant contributions to the TICS from both autoionization and multiple ionization.

  10. Electron-impact vibrational excitation of the hydroxyl radical in the nighttime upper atmosphere

    NASA Astrophysics Data System (ADS)

    Campbell, Laurence; Brunger, Michael J.

    2018-02-01

    Chemical processes produce vibrationally excited hydroxyl (OH) in a layer centred at an altitude of about 87 km in the Earth's atmosphere. Observations of this layer are used to deduce temperatures in the mesosphere and to observe the passage of atmospheric gravity waves. Due to the low densities and energies at night of electrons at the relevant altitude, it is not expected that electron-impact excitation of OH would be significant. However, there are unexplained characteristics of OH densities and radiative emissions that might be explained by electron impact. These are measurements of higher than expected densities of OH above 90 km and of emissions at higher energies that cannot be explained by the chemical production processes. This study simulates the role of electron impact in these processes, using theoretical cross sections for electron-impact excitation of OH. The simulations show that electron impact, even in a substantial aurora, cannot fully explain these phenomena. However, in the process of this investigation, apparent inconsistencies in the theoretical cross sections and reaction rates were found, indicating that measurements of electron-impact excitation of OH are needed to resolve these problems and scale the theoretical predictions to allow more accurate simulations.

  11. Electron-impact dissociation of molecular hydrogen into neutral fragments

    NASA Astrophysics Data System (ADS)

    Scarlett, Liam H.; Tapley, Jonathan K.; Fursa, Dmitry V.; Zammit, Mark C.; Savage, Jeremy S.; Bray, Igor

    2018-02-01

    We present convergent close-coupling calculations of electron-impact dissociation of the ground state of molecular hydrogen into neutral fragments over the range of impact energies from 6 to 300 eV. The calculations account for dissociative excitation, excitation radiative decay dissociation, and predissociation through all bound electronic triplet states, and singlet states up to the D' 1 Π u state. An estimate is given for the contribution from the remaining bound electronic singlet states. Our results are in agreement with the recommended data of Yoon et al. [J. Phys. Chem. Ref. Data 37, 913 (2008)] in the low (6-12 eV) and high (60-70 eV) energy regions, but somewhat lower at the intermediate energies.

  12. Theoretical Calculations for Electron Impact Ionization of Atoms and Molecules

    NASA Astrophysics Data System (ADS)

    Amami, Sadek Mohamed Fituri

    In the last twenty years, significant progress has been made for the theoretical treatment of electron impact ionization (e,2e) of atoms and molecules and, for some cases, very nice agreement between experiment and theory has been achieved. In particular, excellent agreement between theory and experiment and theory has been achieved for ionization of hydrogen and helium. However, agreement between experiment and theory is not nearly as good for ionization of larger atoms and molecules. In the first part of this dissertation, different theoretical approaches will be employed to study the triply differential cross section (TDCS) for low and intermediate energy electron-impact ionization of Neon and Argon for different orbital states. There is a very recent interest in studying ionization of Laser aligned atoms in order to get a better understanding about electron impact ionization of molecules. In the next part of this dissertation, results will be presented for electron-impact ionization of three laser aligned atoms, Mg, Ca, and Na. The comparison between the theory and experiment showed that our three body distorted wave (3DW) model gave excellent agreement with experiment in the scattering plane but very poor agreement perpendicular to the scattering plane. An explanation for this poor agreement out of the scattering plane has been provided by comparing our theoretical results with those of the time depended close coupling (TDCC) model and this explanation is also provided in this dissertation. Recently, significant attention has been directed towards obtaining a better under-standing of electron-impact ionization of molecules which are significantly more challenging than atoms. In the last part of this dissertation, results will be presented for electron-impact ionization of three different molecules (N2 , H2O, and CH4) which have been studied comprehensively using different theoretical approximations for different types of geometries. The published papers in

  13. Absolute calibration of ultraviolet filter photometry

    NASA Technical Reports Server (NTRS)

    Bless, R. C.; Fairchild, T.; Code, A. D.

    1972-01-01

    The essential features of the calibration procedure can be divided into three parts. First, the shape of the bandpass of each photometer was determined by measuring the transmissions of the individual optical components and also by measuring the response of the photometer as a whole. Secondly, each photometer was placed in the essentially-collimated synchrotron radiation bundle maintained at a constant intensity level, and the output signal was determined from about 100 points on the objective. Finally, two or three points on the objective were illuminated by synchrotron radiation at several different intensity levels covering the dynamic range of the photometers. The output signals were placed on an absolute basis by the electron counting technique described earlier.

  14. Ion Densities in the Nightside Ionosphere of Mars: Effects of Electron Impact Ionization

    NASA Astrophysics Data System (ADS)

    Girazian, Z.; Mahaffy, P.; Lillis, R. J.; Benna, M.; Elrod, M.; Fowler, C. M.; Mitchell, D. L.

    2017-11-01

    We use observations from the Mars Atmosphere and Volatile EvolutioN (MAVEN) mission to show how superthermal electron fluxes and crustal magnetic fields affect ion densities in the nightside ionosphere of Mars. We find that due to electron impact ionization, high electron fluxes significantly increase the CO2+, O+, and O2+ densities below 200 km but only modestly increase the NO+ density. High electron fluxes also produce distinct peaks in the CO2+, O+, and O2+ altitude profiles. We also find that superthermal electron fluxes are smaller near strong crustal magnetic fields. Consequently, nightside ion densities are also smaller near strong crustal fields because they decay without being replenished by electron impact ionization. Furthermore, the NO+/O2+ ratio is enhanced near strong crustal fields because, in the absence of electron impact ionization, O2+ is converted into NO+ and not replenished. Our results show that electron impact ionization is a significant source of CO2+, O+, and O2+ in the nightside ionosphere of Mars.

  15. Estimating the absolute wealth of households.

    PubMed

    Hruschka, Daniel J; Gerkey, Drew; Hadley, Craig

    2015-07-01

    To estimate the absolute wealth of households using data from demographic and health surveys. We developed a new metric, the absolute wealth estimate, based on the rank of each surveyed household according to its material assets and the assumed shape of the distribution of wealth among surveyed households. Using data from 156 demographic and health surveys in 66 countries, we calculated absolute wealth estimates for households. We validated the method by comparing the proportion of households defined as poor using our estimates with published World Bank poverty headcounts. We also compared the accuracy of absolute versus relative wealth estimates for the prediction of anthropometric measures. The median absolute wealth estimates of 1,403,186 households were 2056 international dollars per capita (interquartile range: 723-6103). The proportion of poor households based on absolute wealth estimates were strongly correlated with World Bank estimates of populations living on less than 2.00 United States dollars per capita per day (R(2)  = 0.84). Absolute wealth estimates were better predictors of anthropometric measures than relative wealth indexes. Absolute wealth estimates provide new opportunities for comparative research to assess the effects of economic resources on health and human capital, as well as the long-term health consequences of economic change and inequality.

  16. A distorted-wave methodology for electron-ion impact excitation - Calculation for two-electron ions

    NASA Technical Reports Server (NTRS)

    Bhatia, A. K.; Temkin, A.

    1977-01-01

    A distorted-wave program is being developed for calculating the excitation of few-electron ions by electron impact. It uses the exchange approximation to represent the exact initial-state wavefunction in the T-matrix expression for the excitation amplitude. The program has been implemented for excitation of the 2/1,3/(S,P) states of two-electron ions. Some of the astrophysical applications of these cross sections as well as the motivation and requirements of the calculational methodology are discussed.

  17. Electron impact ionization of the gas-phase sorbitol

    NASA Astrophysics Data System (ADS)

    Chernyshova, Irina; Markush, Pavlo; Zavilopulo, Anatoly; Shpenik, Otto

    2015-03-01

    Ionization and dissociative ionization of the sorbitol molecule by electron impact have been studied using two different experimental methods. In the mass range of m/ z = 10-190, the mass spectra of sorbitol were recorded at the ionizing electron energies of 70 and 30 eV. The ion yield curves for the fragment ions have been analyzed and the appearance energies of these ions have been determined. The relative total ionization cross section of the sorbitol molecule was measured using monoenergetic electron beam. Possible fragmentation pathways for the sorbitol molecule were proposed.

  18. Estimating the absolute wealth of households

    PubMed Central

    Gerkey, Drew; Hadley, Craig

    2015-01-01

    Abstract Objective To estimate the absolute wealth of households using data from demographic and health surveys. Methods We developed a new metric, the absolute wealth estimate, based on the rank of each surveyed household according to its material assets and the assumed shape of the distribution of wealth among surveyed households. Using data from 156 demographic and health surveys in 66 countries, we calculated absolute wealth estimates for households. We validated the method by comparing the proportion of households defined as poor using our estimates with published World Bank poverty headcounts. We also compared the accuracy of absolute versus relative wealth estimates for the prediction of anthropometric measures. Findings The median absolute wealth estimates of 1 403 186 households were 2056 international dollars per capita (interquartile range: 723–6103). The proportion of poor households based on absolute wealth estimates were strongly correlated with World Bank estimates of populations living on less than 2.00 United States dollars per capita per day (R2 = 0.84). Absolute wealth estimates were better predictors of anthropometric measures than relative wealth indexes. Conclusion Absolute wealth estimates provide new opportunities for comparative research to assess the effects of economic resources on health and human capital, as well as the long-term health consequences of economic change and inequality. PMID:26170506

  19. Electronic management: Exploring its impact on small business

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bewayo, E.D.

    Macworld magazine recently reported that more than one in five companies eavesdrops electronically on its employees. Electronic eavesdropping is one name given to electronic management Besides being known as electronic eaves-dropping, electronic management also goes by electronic monitoring, electronic supervision, electronic snooping, electronic sweat-shopping, electronic surveillance, electronic Big Brothering, and computerized performance monitoring. Some of these labels connote negative things about electronic management, and relate to applications of electronic management to extreme and unreasonable levels. In the rest of this paper the terms electronic management and electronic monitoring will be used interchangeably. In this paper we discuss the impacts ofmore » electronic management, positive and negative, on workplaces, with emphasis on small businesses. This small business emphasis is partly because of the author`s research interests, and partly because most of what has been written on electronic management has been based on large business contexts. This large business bias has been partly due to the fact that the early inroads of electronic management were almost exclusively limited to large companies--beginning with telephone service observation in the late 1800s. However, now with the growing affordability and, consequently, the proliferation of electronic technology (especially the computer), electronic management is no longer the monopoly of large corporations. Electronic management has now reached restaurants, drug stores, liquor stores, convenience stores, and trucking companies. And in some industries, e.g., banking, every business, regardless of size, uses electronic monitoring.« less

  20. Cell wall microstructure, pore size distribution and absolute density of hemp shiv

    NASA Astrophysics Data System (ADS)

    Jiang, Y.; Lawrence, M.; Ansell, M. P.; Hussain, A.

    2018-04-01

    This paper, for the first time, fully characterizes the intrinsic physical parameters of hemp shiv including cell wall microstructure, pore size distribution and absolute density. Scanning electron microscopy revealed microstructural features similar to hardwoods. Confocal microscopy revealed three major layers in the cell wall: middle lamella, primary cell wall and secondary cell wall. Computed tomography improved the visualization of pore shape and pore connectivity in three dimensions. Mercury intrusion porosimetry (MIP) showed that the average accessible porosity was 76.67 ± 2.03% and pore size classes could be distinguished into micropores (3-10 nm) and macropores (0.1-1 µm and 20-80 µm). The absolute density was evaluated by helium pycnometry, MIP and Archimedes' methods. The results show that these methods can lead to misinterpretation of absolute density. The MIP method showed a realistic absolute density (1.45 g cm-3) consistent with the density of the known constituents, including lignin, cellulose and hemi-cellulose. However, helium pycnometry and Archimedes' methods gave falsely low values owing to 10% of the volume being inaccessible pores, which require sample pretreatment in order to be filled by liquid or gas. This indicates that the determination of the cell wall density is strongly dependent on sample geometry and preparation.

  1. 20 CFR 404.1205 - Absolute coverage groups.

    Code of Federal Regulations, 2011 CFR

    2011-04-01

    ... 20 Employees' Benefits 2 2011-04-01 2011-04-01 false Absolute coverage groups. 404.1205 Section... Covered § 404.1205 Absolute coverage groups. (a) General. An absolute coverage group is a permanent... are not under a retirement system. An absolute coverage group may include positions which were...

  2. Electron impact excitation of methane

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Trajmar, S.

    1983-01-01

    A crossed molecular beam-electron beam apparatus was employed to examine the excitation cross-sections of CH4. Attention was given to 20, 30, and 200 eV impact energies at angles from 8-130 deg. Spectra were obtained in the elastic and inelastic realms as well as in the ionization continuum in the 12.99-15.0 eV energy-loss range. Differential cross-sections were also determined. The results are useful for modeling the behavior of CH4 in planetary atmospheres.

  3. Venus nightside ionosphere - A model with KeV electron impact ionization

    NASA Technical Reports Server (NTRS)

    Kumar, S.

    1982-01-01

    The impact of keV electrons is proposed as the strongest source of ionization in a full-up Venus nightside ionosphere model for the equatorial midnight region. The electron impacts lead to a peak ion density of 100,000/cu cm, which was observed by the PV-OIMS experiment on several occasions. In addition, the observed altitude profiles of CO2(+), O(+), O2(+), H(+), and H2(+) can be reproduced by the model on condition that the available keV electron flux is approximated by a reasonable extrapolation from fluxes observed at lower energies.

  4. Dissociative Excitation of Thymine by Electron Impact

    NASA Astrophysics Data System (ADS)

    McConkey, William; Tiessen, Collin; Hein, Jeffrey; Trocchi, Joshuah; Kedzierski, Wladek

    2014-05-01

    A crossed electron-gas beam system coupled to a VUV spectrometer has been used to investigate the dissociation of thymine (C5H6N2O2) into excited atomic fragments in the electron-impact energy range from threshold to 375 eV. A special stainless steel oven is used to vaporize the thymine and form it into a beam where it is intersected by a magnetically collimated electron beam, typical current 50 μA. The main features in the spectrum are the H Lyman series lines. The probability of extracting excited C or N atoms from the ring is shown to be very small. In addition to spectral data, excitation probability curves as a function of electron energy will be presented for the main emission features. Possible dissociation channels and excitation mechanisms in the parent molecule will be discussed. The authors thank NSERC (Canada) for financial support.

  5. The Impact of Different Absolute Solar Irradiance Values on Current Climate Model Simulations

    NASA Technical Reports Server (NTRS)

    Rind, David H.; Lean, Judith L.; Jonas, Jeffrey

    2014-01-01

    Simulations of the preindustrial and doubled CO2 climates are made with the GISS Global Climate Middle Atmosphere Model 3 using two different estimates of the absolute solar irradiance value: a higher value measured by solar radiometers in the 1990s and a lower value measured recently by the Solar Radiation and Climate Experiment. Each of the model simulations is adjusted to achieve global energy balance; without this adjustment the difference in irradiance produces a global temperature change of 0.48C, comparable to the cooling estimated for the Maunder Minimum. The results indicate that by altering cloud cover the model properly compensates for the different absolute solar irradiance values on a global level when simulating both preindustrial and doubled CO2 climates. On a regional level, the preindustrial climate simulations and the patterns of change with doubled CO2 concentrations are again remarkably similar, but there are some differences. Using a higher absolute solar irradiance value and the requisite cloud cover affects the model's depictions of high-latitude surface air temperature, sea level pressure, and stratospheric ozone, as well as tropical precipitation. In the climate change experiments it leads to an underestimation of North Atlantic warming, reduced precipitation in the tropical western Pacific, and smaller total ozone growth at high northern latitudes. Although significant, these differences are typically modest compared with the magnitude of the regional changes expected for doubled greenhouse gas concentrations. Nevertheless, the model simulations demonstrate that achieving the highest possible fidelity when simulating regional climate change requires that climate models use as input the most accurate (lower) solar irradiance value.

  6. Electron-impact coherence parameters for 41 P 1 excitation of zinc

    NASA Astrophysics Data System (ADS)

    Piwiński, Mariusz; Kłosowski, Łukasz; Chwirot, Stanisław; Fursa, Dmitry V.; Bray, Igor; Das, Tapasi; Srivastava, Rajesh

    2018-04-01

    We present electron-impact coherence parameters (EICP) for electron-impact excitation of 41 P 1 state of zinc atoms for collision energies 40 eV and 60 eV. The experimental results are presented together with convergent close-coupling and relativistic distorted-wave approximation theoretical predictions. The results are compared and discussed with EICP data for collision energies 80 eV and 100 eV.

  7. Electron-impact ionization and electron attachment cross sections of radicals important in transient gaseous discharges

    NASA Technical Reports Server (NTRS)

    Lee, Long C.; Srivastava, Santosh K.

    1990-01-01

    Electron-impact ionization and electron attachment cross sections of radicals and excited molecules were measured using an apparatus that consists of an electron beam, a molecular beam and a laser beam. The information obtained is needed for the pulse power applications in the areas of high power gaseous discharge switches, high energy lasers, particle beam experiments, and electromagnetic pulse systems. The basic data needed for the development of optically-controlled discharge switches were also investigated. Transient current pulses induced by laser irradiation of discharge media were observed and applied for the study of electron-molecule reaction kinetics in gaseous discharges.

  8. Electron-impact ionization of silicon tetrachloride (SiCl4).

    PubMed

    Basner, R; Gutkin, M; Mahoney, J; Tarnovsky, V; Deutsch, H; Becker, K

    2005-08-01

    We measured absolute partial cross sections for the formation of various singly charged and doubly charged positive ions produced by electron impact on silicon tetrachloride (SiCl4) using two different experimental techniques, a time-of-flight mass spectrometer (TOF-MS) and a fast-neutral-beam apparatus. The energy range covered was from the threshold to 900 eV in the TOF-MS and to 200 eV in the fast-neutral-beam apparatus. The results obtained by the two different experimental techniques were found to agree very well (better than their combined margins of error). The SiCl3(+) fragment ion has the largest partial ionization cross section with a maximum value of slightly above 6x10(-20) m2 at about 100 eV. The cross sections for the formation of SiCl4(+), SiCl+, and Cl+ have maximum values around 4x10(-20) m2. Some of the cross-section curves exhibit an unusual energy dependence with a pronounced low-energy maximum at an energy around 30 eV followed by a broad second maximum at around 100 eV. This is similar to what has been observed by us earlier for another Cl-containing molecule, TiCl4 [R. Basner, M. Schmidt, V. Tamovsky, H. Deutsch, and K. Becker, Thin Solid Films 374 291 (2000)]. The maximum cross-section values for the formation of the doubly charged ions, with the exception of SiCl3(++), are 0.05x10(-20) m2 or less. The experimentally determined total single ionization cross section of SiCl4 is compared with the results of semiempirical calculations.

  9. A novel approach of an absolute coding pattern based on Hamiltonian graph

    NASA Astrophysics Data System (ADS)

    Wang, Ya'nan; Wang, Huawei; Hao, Fusheng; Liu, Liqiang

    2017-02-01

    In this paper, a novel approach of an optical type absolute rotary encoder coding pattern is presented. The concept is based on the principle of the absolute encoder to find out a unique sequence that ensures an unambiguous shaft position of any angular. We design a single-ring and a n-by-2 matrix absolute encoder coding pattern by using the variations of Hamiltonian graph principle. 12 encoding bits is used in the single-ring by a linear array CCD to achieve an 1080-position cycle encoding. Besides, a 2-by-2 matrix is used as an unit in the 2-track disk to achieve a 16-bits encoding pattern by using an area array CCD sensor (as a sample). Finally, a higher resolution can be gained by an electronic subdivision of the signals. Compared with the conventional gray or binary code pattern (for a 2n resolution), this new pattern has a higher resolution (2n*n) with less coding tracks, which means the new pattern can lead to a smaller encoder, which is essential in the industrial production.

  10. Enantiomeric high-performance liquid chromatography resolution and absolute configuration of 6β-benzoyloxy-3α-tropanol.

    PubMed

    Muñoz, Marcelo A; González, Natalia; Joseph-Nathan, Pedro

    2016-07-01

    The absolute configuration of the naturally occurring isomers of 6β-benzoyloxy-3α-tropanol (1) has been established by the combined use of chiral high-performance liquid chromatography with electronic circular dichroism detection and optical rotation detection. For this purpose (±)-1, prepared in two steps from racemic 6-hydroxytropinone (4), was subjected to chiral high-performance liquid chromatography with electronic circular dichroism and optical rotation detection allowing the online measurement of both chiroptical properties for each enantiomer, which in turn were compared with the corresponding values obtained from density functional theory calculations. In an independent approach, preparative high-performance liquid chromatography separation using an automatic fraction collector, yielded an enantiopure sample of OR (+)-1 whose vibrational circular dichroism spectrum allowed its absolute configuration assignment when the bands in the 1100-950 cm(-1) region were compared with those of the enantiomers of esters derived from 3α,6β-tropanediol. In addition, an enantiomerically enriched sample of 4, instead of OR (±)-4, was used for the same transformation sequence, whose high-performance liquid chromatography follow-up allowed their spectroscopic correlation. All evidences lead to the OR (+)-(1S,3R,5S,6R) and OR (-)-(1R,3S,5R,6S) absolute configurations, from where it follows that samples of 1 isolated from Knightia strobilina and Erythroxylum zambesiacum have the OR (+)-(1S,3R,5S,6R) absolute configuration, while the sample obtained from E. rotundifolium has the OR (-)-(1R,3S,5R,6S) absolute configuration. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  11. Molybdenum electron impact width parameter measurement by laser-induced breakdown spectroscopy

    NASA Astrophysics Data System (ADS)

    Sternberg, E. M. A.; Rodrigues, N. A. S.; Amorim, J.

    2016-01-01

    In this work, we suggest a method for electron impact width parameter calculation based on Stark broadening of emission lines of a laser-ablated plasma plume. First, electron density and temperature must be evaluated by means of the Saha-Boltzmann plot method for neutral and ionized species of the plasma. The method was applied for laser-ablated molybdenum plasma plume. For molybdenum plasma electron temperature, which varies around 10,000 K, and electron density, which reaches values around 1018 cm-3, and considering that total measured line broadening was due experimental and Stark broadening mainly, electron impact width parameter of molybdenum emission lines was determined as (0.01 ± 0.02) nm. Intending to validate the presented method, it was analyzed the laser-ablated aluminum plasma plume and the obtained results were in agreement with the predicted on the literature.

  12. The protoelectric potential map (PPM): an absolute two-dimensional chemical potential scale for a global understanding of chemistry.

    PubMed

    Radtke, Valentin; Himmel, Daniel; Pütz, Katharina; Goll, Sascha K; Krossing, Ingo

    2014-04-07

    We introduce the protoelectric potential map (PPM) as a novel, two-dimensional plot of the absolute reduction potential (peabs scale) combined with the absolute protochemical potential (Brønsted acidity: pHabs scale). The validity of this thermodynamically derived PPM is solvent-independent due to the scale zero points, which were chosen as the ideal electron gas and the ideal proton gas at standard conditions. To tie a chemical environment to these reference states, the standard Gibbs energies for the transfer of the gaseous electrons/protons to the medium are needed as anchor points. Thereby, the thermodynamics of any redox, acid-base or combined system in any medium can be related to any other, resulting in a predictability of reactions even over different media or phase boundaries. Instruction is given on how to construct the PPM from the anchor points derived and tabulated with this work. Since efforts to establish "absolute" reduction potential scales and also "absolute" pH scales already exist, a short review in this field is given and brought into relation to the PPM. Some comments on the electrochemical validation and realization conclude this concept article. © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  13. Vibrational excitation of water by electron impact

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Khakoo, M. A.; Winstead, C.; McKoy, V.

    2009-05-15

    Experimental and calculated differential cross sections (DCSs) for electron-impact excitation of the (010) bending mode and unresolved (100) symmetric and (001) antisymmetric stretching modes of water are presented. Measurements are reported at incident energies of 1-100 eV and scattering angles of 10 deg. - 130 deg. and are normalized to the elastic-scattering DCSs for water determined earlier by our group. The calculated cross sections are obtained in the adiabatic approximation from fixed-nuclei, electronically elastic scattering calculations using the Schwinger multichannel method. The present results are compared to available experimental and theoretical data.

  14. Enhanced production of low energy electrons by alpha particle impact

    PubMed Central

    Kim, Hong-Keun; Titze, Jasmin; Schöffler, Markus; Trinter, Florian; Waitz, Markus; Voigtsberger, Jörg; Sann, Hendrik; Meckel, Moritz; Stuck, Christian; Lenz, Ute; Odenweller, Matthias; Neumann, Nadine; Schössler, Sven; Ullmann-Pfleger, Klaus; Ulrich, Birte; Fraga, Rui Costa; Petridis, Nikos; Metz, Daniel; Jung, Annika; Grisenti, Robert; Czasch, Achim; Jagutzki, Ottmar; Schmidt, Lothar; Jahnke, Till; Schmidt-Böcking, Horst; Dörner, Reinhard

    2011-01-01

    Radiation damage to living tissue stems not only from primary ionizing particles but to a substantial fraction from the dissociative attachment of secondary electrons with energies below the ionization threshold. We show that the emission yield of those low energy electrons increases dramatically in ion–atom collisions depending on whether or not the target atoms are isolated or embedded in an environment. Only when the atom that has been ionized and excited by the primary particle impact is in immediate proximity of another atom is a fragmentation route known as interatomic Coulombic decay (ICD) enabled. This leads to the emission of a low energy electron. Over the past decade ICD was explored in several experiments following photoionization. Most recent results show its observation even in water clusters. Here we show the quantitative role of ICD for the production of low energy electrons by ion impact, thus approaching a scenario closer to that of radiation damage by alpha particles: We choose ion energies on the maximum of the Bragg peak where energy is most efficiently deposited in tissue. We compare the electron production after colliding He+ ions on isolated Ne atoms and on Ne dimers (Ne2). In the latter case the Ne atom impacted is surrounded by a most simple environment already opening ICD as a deexcitation channel. As a consequence, we find a dramatically enhanced low energy electron yield. The results suggest that ICD may have a significant influence on cell survival after exposure to ionizing radiation. PMID:21730184

  15. Electron-impact excitation of diatomic hydride cations II: OH+ and SH+

    NASA Astrophysics Data System (ADS)

    Hamilton, James R.; Faure, Alexandre; Tennyson, Jonathan

    2018-05-01

    R-matrix calculations combined with the adiabatic-nuclei-rotation and Coulomb-Born approximations are used to compute electron-impact rotational rate coefficients for two open-shell diatomic cations of astrophysical interest: the hydoxyl and sulphanyl ions, OH+ and SH+. Hyperfine resolved rate coefficients are deduced using the infinite-order-sudden approximation. The propensity rule ΔF = Δj = ΔN = ±1 is observed, as is expected for cations with a large dipole moment. A model for OH+ excitation in the Orion Bar photon-dominated region is presented which nicely reproduces Herschel observations for an electron fraction xe = 10-4 and an OH+ column density of 3 × 1013 cm-2. Electron-impact electronic excitation cross-sections and rate coefficients for the ions are also presented.

  16. Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Olalla, Carlos; Maksimovic, Dragan; Deline, Chris

    Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

  17. Impact of distributed power electronics on the lifetime and reliability of PV systems: Impact of distributed power electronics

    DOE PAGES

    Olalla, Carlos; Maksimovic, Dragan; Deline, Chris; ...

    2017-04-26

    Here, this paper quantifies the impact of distributed power electronics in photovoltaic (PV) systems in terms of end-of-life energy-capture performance and reliability. The analysis is based on simulations of PV installations over system lifetime at various degradation rates. It is shown how module-level or submodule-level power converters can mitigate variations in cell degradation over time, effectively increasing the system lifespan by 5-10 years compared with the nominal 25-year lifetime. An important aspect typically overlooked when characterizing such improvements is the reliability of distributed power electronics, as power converter failures may not only diminish energy yield improvements but also adversely affectmore » the overall system operation. Failure models are developed, and power electronics reliability is taken into account in this work, in order to provide a more comprehensive view of the opportunities and limitations offered by distributed power electronics in PV systems. Lastly, it is shown how a differential power-processing approach achieves the best mismatch mitigation performance and the least susceptibility to converter faults.« less

  18. A high-performance liquid chromatography-electronic circular dichroism online method for assessing the absolute enantiomeric excess and conversion ratio of asymmetric reactions

    NASA Astrophysics Data System (ADS)

    Zhang, Xiang; Wang, Mingchao; Li, Li; Yin, Dali

    2017-03-01

    Asymmetric reactions often need to be evaluated during the synthesis of chiral compounds. However, traditional evaluation methods require the isolation of the individual enantiomer, which is tedious and time-consuming. Thus, it is desirable to develop simple, practical online detection methods. We developed a method based on high-performance liquid chromatography-electronic circular dichroism (HPLC-ECD) that simultaneously analyzes the material conversion ratio and absolute optical purity of each enantiomer. In particular, only a reverse-phase C18 column instead of a chiral column is required in our method because the ECD measurement provides a g-factor that describes the ratio of each enantiomer in the mixtures. We used our method to analyze the asymmetric hydrosilylation of β-enamino esters, and we discussed the advantage, feasibility, and effectiveness of this new methodology.

  19. [Prognostic value of absolute monocyte count in chronic lymphocytic leukaemia].

    PubMed

    Szerafin, László; Jakó, János; Riskó, Ferenc

    2015-04-01

    The low peripheral absolute lymphocyte and high monocyte count have been reported to correlate with poor clinical outcome in various lymphomas and other cancers. However, a few data known about the prognostic value of absolute monocyte count in chronic lymphocytic leukaemia. The aim of the authors was to investigate the impact of absolute monocyte count measured at the time of diagnosis in patients with chronic lymphocytic leukaemia on the time to treatment and overal survival. Between January 1, 2005 and December 31, 2012, 223 patients with newly-diagnosed chronic lymphocytic leukaemia were included. The rate of patients needing treatment, time to treatment, overal survival and causes of mortality based on Rai stages, CD38, ZAP-70 positivity and absolute monocyte count were analyzed. Therapy was necessary in 21.1%, 57.4%, 88.9%, 88.9% and 100% of patients in Rai stage 0, I, II, III an IV, respectively; in 61.9% and 60.8% of patients exhibiting CD38 and ZAP-70 positivity, respectively; and in 76.9%, 21.2% and 66.2% of patients if the absolute monocyte count was <0.25 G/l, between 0.25-0.75 G/l and >0.75 G/l, respectively. The median time to treatment and the median overal survival were 19.5, 65, and 35.5 months; and 41.5, 65, and 49.5 months according to the three groups of monocyte counts. The relative risk of beginning the therapy was 1.62 (p<0.01) in patients with absolute monocyte count <0.25 G/l or >0.75 G/l, as compared to those with 0.25-0.75 G/l, and the risk of overal survival was 2.41 (p<0.01) in patients with absolute monocyte count lower than 0.25 G/l as compared to those with higher than 0.25 G/l. The relative risks remained significant in Rai 0 patients, too. The leading causes of mortality were infections (41.7%) and the chronic lymphocytic leukaemia (58.3%) in patients with low monocyte count, while tumours (25.9-35.3%) and other events (48.1 and 11.8%) occurred in patients with medium or high monocyte counts. Patients with low and high monocyte

  20. Electron impact ionization in the vicinity of comets

    NASA Astrophysics Data System (ADS)

    Cravens, T. E.; Kozyra, J. U.; Nagy, A. F.; Gombosi, T. I.; Kurtz, M.

    1987-07-01

    The solar wind interacts very strongly with the extensive cometary coma, and the various interaction processes are initiated by the ionization of cometary neutrals. The main ionization mechanism far outside the cometary bow shock is photoionization by solar extreme ultraviolet radiation.Electron distributions measured in the vicinity of comets Halley and Giacobini-Zinner by instruments on the VEGA and ICE spacecraft, respectively, are used to calculate electron impact ionization frequencies. Ionization by electrons is of comparable importance to photoionization in the magnetosheaths of Comets Halley and Giacobini-Zinner. The ionization frequency in the inner part of the cometary plasma region of comet Halley is several times greater than the photoionization value. Tables of ionization frequencies as functions of electron temperature are presented for H2O, CO2, CO, O, N2, and H.

  1. Potential resource and toxicity impacts from metals in waste electronic devices.

    PubMed

    Woo, Seung H; Lee, Dae Sung; Lim, Seong-Rin

    2016-04-01

    As a result of the continuous release of new electronic devices, existing electronic devices are quickly made obsolete and rapidly become electronic waste (e-waste). Because e-waste contains a variety of metals, information about those metals with the potential for substantial environmental impact should be provided to manufacturers, recyclers, and disposers to proactively reduce this impact. This study assesses the resource and toxicity (i.e., cancer, noncancer, and ecotoxicity) potentials of various heavy metals commonly found in e-waste from laptop computers, liquid-crystal display (LCD) monitors, LCD TVs, plasma TVs, color cathode ray tube (CRT) TVs, and cell phones and then evaluates such potentials using life cycle impact-based methods. Resource potentials derive primarily from Cu, Sb, Ag, and Pb. Toxicity potentials derive primarily from Pb, Ni, and Hg for cancer toxicity; from Pb, Hg, Zn, and As for noncancer toxicity; and from Cu, Pb, Hg, and Zn for ecotoxicity. Therefore, managing these heavy metals should be a high priority in the design, recycling, and disposal stages of electronic devices. © 2015 SETAC.

  2. Cell wall microstructure, pore size distribution and absolute density of hemp shiv

    PubMed Central

    Lawrence, M.; Ansell, M. P.; Hussain, A.

    2018-01-01

    This paper, for the first time, fully characterizes the intrinsic physical parameters of hemp shiv including cell wall microstructure, pore size distribution and absolute density. Scanning electron microscopy revealed microstructural features similar to hardwoods. Confocal microscopy revealed three major layers in the cell wall: middle lamella, primary cell wall and secondary cell wall. Computed tomography improved the visualization of pore shape and pore connectivity in three dimensions. Mercury intrusion porosimetry (MIP) showed that the average accessible porosity was 76.67 ± 2.03% and pore size classes could be distinguished into micropores (3–10 nm) and macropores (0.1–1 µm and 20–80 µm). The absolute density was evaluated by helium pycnometry, MIP and Archimedes' methods. The results show that these methods can lead to misinterpretation of absolute density. The MIP method showed a realistic absolute density (1.45 g cm−3) consistent with the density of the known constituents, including lignin, cellulose and hemi-cellulose. However, helium pycnometry and Archimedes’ methods gave falsely low values owing to 10% of the volume being inaccessible pores, which require sample pretreatment in order to be filled by liquid or gas. This indicates that the determination of the cell wall density is strongly dependent on sample geometry and preparation. PMID:29765652

  3. Unravelling the structural-electronic impact of arylamine electron-donating antennas on the performances of efficient ruthenium sensitizers for dye-sensitized solar cells

    NASA Astrophysics Data System (ADS)

    Chen, Wang-Chao; Kong, Fan-Tai; Ghadari, Rahim; Li, Zhao-Qian; Guo, Fu-Ling; Liu, Xue-Peng; Huang, Yang; Yu, Ting; Hayat, Tasawar; Dai, Song-Yuan

    2017-04-01

    We report a systematic research to understand the structural-electronic impact of the arylamine electron-donating antennas on the performances of the ruthenium complexes for dye-sensitized solar cells. Three ruthenium complexes functionalized with different arylamine electron-donating antennas (N,N-diethyl-aniline in RC-31, julolidine in RC-32 and N,N-dibenzyl-aniline in RC-36) are designed and synthesized. The photoelectric properties of RC dyes exhibit apparent discrepancy, which are ascribed to different structural nature and electronic delocalization ability of these arylamine electron-donating system. In conjunction with TiO2 microspheres photoanode and a typical coadsorbent DPA, the devices sensitized by RC-36 achieve the best conversion efficiency of 10.23%. The UV-Vis absorption, electrochemical measurement, incident photon-to-current conversion efficiency and transient absorption spectra confirm that the excellent performance of RC-36 is induced by synergistically structural-electronic impacts from enhanced absorption capacity and well-tuned electronic characteristics. These observations provide valuable insights into the molecular engineering methodology based on fine tuning structural-electronic impact of electron-donating antenna in efficient ruthenium sensitizers.

  4. Absolute Definition of Phase Shift in the Elastic Scattering of a Particle from Compound Systems

    NASA Technical Reports Server (NTRS)

    Temkin, A.

    1961-01-01

    The projection of the target wave function on the total wave function of a scattered particle interacting with the target system is used to define an absolute phase shift including any multiples of pi. With this definition of the absolute phase shift, one can prove rigorously in the limit of zero energy for s-wave electrons scattered from atomic hydrogen that the triplet phase shift must approach a nonzero multiple of pi. One can further show that at least one pi of this phase shift is not connected with the existence of a bound state of the H- ion.

  5. Electron impact ionisation cross section for organoplatinum compounds

    NASA Astrophysics Data System (ADS)

    Mahato, Dibyendu; Naghma, Rahla; Alam, Mohammad Jane; Ahmad, Shabbir; Antony, Bobby

    2016-11-01

    This article reports electron impact ionisation cross sections for platinum-based drugs viz., cisplatin (H6N2Cl2Pt), carboplatin (C6H12N2O4Pt), oxaliplatin (C8H14N2O4Pt), nedaplatin (C2H8N2O3Pt) and satraplatin (C10H22ClN2O4Pt) complexes used in the cancer chemotherapy. The multi-scattering centre spherical complex optical potential formalism is used to obtain the inelastic cross section for these large molecules upon electron impact. The ionisation cross section is derived from the inelastic cross section employing complex scattering potential-ionisation contribution method. Comparison is made with previous results, where ever available and overall a reasonable agreement is observed. This is the first attempt to report total ionisation cross sections for nedaplatin and satraplatin complexes.

  6. Ultraviolet photometry from the Orbiting Astronomical Observatory. XXI - Absolute energy distribution of stars in the ultraviolet

    NASA Technical Reports Server (NTRS)

    Bless, R. C.; Code, A. D.; Fairchild, E. T.

    1976-01-01

    The absolute energy distribution in the ultraviolet is given for the stars alpha Vir, eta UMa, and alpha Leo. The calibration is based on absolute heterochromatic photometry between 2920 and 1370 A carried out with an Aerobee sounding rocket. The fundamental radiation standard is the synchrotron radiation from 240-MeV electrons in a certain synchrotron storage ring. On the basis of the sounding-rocket calibration, the preliminary OAO-2 spectrometer calibration has been revised; the fluxes for the three program stars are tabulated in energy per second per square centimeter per unit wavelength interval.

  7. Lunar Cratering Chronology: Calibrating Degree of Freshness of Craters to Absolute Ages

    NASA Astrophysics Data System (ADS)

    Trang, D.; Gillis-Davis, J.; Boyce, J. M.

    2013-12-01

    The use of impact craters to age-date surfaces of and/or geomorphological features on planetary bodies is a decades old practice. Various dating techniques use different aspects of impact craters in order to determine ages. One approach is based on the degree of freshness of primary-impact craters. This method examines the degradation state of craters through visual inspection of seven criteria: polygonality, crater ray, continuous ejecta, rim crest sharpness, satellite craters, radial channels, and terraces. These criteria are used to rank craters in order of age from 0.0 (oldest) to 7.0 (youngest). However, the relative decimal scale used in this technique has not been tied to a classification of absolute ages. In this work, we calibrate the degree of freshness to absolute ages through crater counting. We link the degree of freshness to absolute ages through crater counting of fifteen craters with diameters ranging from 5-22 km and degree of freshness from 6.3 to 2.5. We use the Terrain Camera data set on Kaguya to count craters on the continuous ejecta of each crater in our sample suite. Specifically, we divide the crater's ejecta blanket into quarters and count craters between the rim of the main crater out to one crater radii from the rim for two of the four sections. From these crater counts, we are able to estimate the absolute model age of each main crater using the Craterstats2 tool in ArcGIS. Next, we compare the degree of freshness for the crater count-derived age of our main craters to obtain a linear inverse relation that links these two metrics. So far, for craters with degree of freshness from 6.3 to 5.0, the linear regression has an R2 value of 0.7, which corresponds to a relative uncertainty of ×230 million years. At this point, this tool that links degree of freshness to absolute ages cannot be used with craters <8km because this class of crater degrades quicker than larger craters. A graphical solution exists for correcting the degree of

  8. Soluble fullerene derivatives: The effect of electronic structure on transistor performance and air stability

    NASA Astrophysics Data System (ADS)

    Ball, James M.; Bouwer, Ricardo K. M.; Kooistra, Floris B.; Frost, Jarvist M.; Qi, Yabing; Domingo, Ester Buchaca; Smith, Jeremy; de Leeuw, Dago M.; Hummelen, Jan C.; Nelson, Jenny; Kahn, Antoine; Stingelin, Natalie; Bradley, Donal D. C.; Anthopoulos, Thomas D.

    2011-07-01

    The family of soluble fullerene derivatives comprises a widely studied group of electron transporting molecules for use in organic electronic and optoelectronic devices. For electronic applications, electron transporting (n-channel) materials are required for implementation into organic complementary logic circuit architectures. To date, few soluble candidate materials have been studied that fulfill the stringent requirements of high carrier mobility and air stability. Here we present a study of three soluble fullerenes with varying electron affinity to assess the impact of electronic structure on device performance and air stability. Through theoretical and experimental analysis of the electronic structure, characterization of thin-film structure, and characterization of transistor device properties we find that the air stability of the present series of fullerenes not only depends on the absolute electron affinity of the semiconductor but also on the disorder within the thin-film.

  9. Differential cross sections for the electron impact ionization of Ar (3 p) atoms for equal energy final state electrons

    NASA Astrophysics Data System (ADS)

    Purohit, Ghanshyam; Singh, Prithvi

    2017-06-01

    The electron-impact ionization of inert gases for asymmetric final state energy sharing conditions has been studied in detail. However, there have been relatively few studies examining equal energy final state electrons. We report in this communication the results of triple differential cross sections (TDCSs) for electron impact ionization of Ar (3 p) for equal energy sharing of the outgoing electrons. We calculate TDCS in the modified distorted wave Born approximation (DWBA) formalism including post collision interaction (PCI) and polarization potential. We compare the results of our calculation with available measurements [Phys. Rev. A 87, 022712 (2013)]. We study the effect of PCI, target polarization on the trends of TDCS for the single ionization of Ar (3 p) targets.

  10. High energy electron acceleration with PW-class laser system

    NASA Astrophysics Data System (ADS)

    Nakanii, N.; Kondo, K.; Mori, Y.; Miura, E.; Yabuuchi, T.; Tsuji, K.; Suzuki, S.; Asaka, T.; Yanagida, K.; Hanaki, H.; Kobayashi, T.; Makino, K.; Yamane, T.; Miyamoto, S.; Horikawa, K.; Kimura, K.; Takeda, K.; Fukumochi, S.; Kashihara, M.; Tanimoto, T.; Nakamura, H.; Ishikura, T.; Tampo, M.; Kodama, R.; Kitagawa, Y.; Mima, K.; Tanaka, K. A.

    2008-06-01

    We performed electron acceleration experiment with PW-class laser and a plasma tube, which was created by imploding a hollow polystyrene cylinder. In this experiment, electron energies in excess of 600 MeV have been observed. Moreover, the spectra of a comparatively high-density plasma ˜1019 cm-3 had a bump around 10 MeV. Additionally, we performed the absolute sensitivity calibration of imaging plate for 1 GeV electrons from the injector Linac of Spring-8 in order to evaluate absolute number of GeV-class electrons in the laser acceleration experiment.

  11. Determination of absolute configuration of natural products: theoretical calculation of electronic circular dichroism as a tool

    USDA-ARS?s Scientific Manuscript database

    Determination of absolute configuration (AC) is one of the most challenging features in the structure elucidation of chiral natural products, especially those with complex structures. With revolutionary advancements in the area of quantum chemical calculations of chiroptical spectroscopy over the pa...

  12. Forecasting Error Calculation with Mean Absolute Deviation and Mean Absolute Percentage Error

    NASA Astrophysics Data System (ADS)

    Khair, Ummul; Fahmi, Hasanul; Hakim, Sarudin Al; Rahim, Robbi

    2017-12-01

    Prediction using a forecasting method is one of the most important things for an organization, the selection of appropriate forecasting methods is also important but the percentage error of a method is more important in order for decision makers to adopt the right culture, the use of the Mean Absolute Deviation and Mean Absolute Percentage Error to calculate the percentage of mistakes in the least square method resulted in a percentage of 9.77% and it was decided that the least square method be worked for time series and trend data.

  13. Dissociative Excitation of Adenine by Electron Impact

    NASA Astrophysics Data System (ADS)

    McConkey, J. William; Trocchi, Joshuah; Dech, Jeffery; Kedzierski, Wladek

    2017-04-01

    Dissociative excitation of adenine (C6H5NH2) into excited atomic fragments has been studied in the electron impact energy range from threshold to 300 eV. A crossed beam system coupled to a vacuum ultraviolet (VUV) monochromator is used to study emissions in the wavelength range from 110 to 200 nm. The beam of adenine vapor from a stainless steel oven is crossed at right angles by the electron beam and the resultant UV radiation is detected in a mutually orthogonal direction. The strongest feature in the spectrum is H Lyman- α. Financial support from NSERC and CFI, Canada, is gratefully acknowledged.

  14. Absolute vibrational numbering from isotope shifts in fragmentary spectroscopic data

    NASA Astrophysics Data System (ADS)

    Pashov, A.; Kowalczyk, P.; Jastrzebski, W.

    2018-05-01

    We discuss application of the isotope effect to establish the absolute vibrational numbering in electronic states of diatomic molecules. This is illustrated by examples of states with potential energy curves of both regular and irregular shape, with one or two potential minima. The minimum number of spectroscopic data (either term values or spectral line positions) necessary to provide a unique numbering is considered. We show that at favourable conditions just four term energies (or spectral lines) in one isotopologue and one term energy in the other suffice.

  15. 20 CFR 404.1205 - Absolute coverage groups.

    Code of Federal Regulations, 2014 CFR

    2014-04-01

    ... 20 Employees' Benefits 2 2014-04-01 2014-04-01 false Absolute coverage groups. 404.1205 Section... INSURANCE (1950- ) Coverage of Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1205 Absolute coverage groups. (a) General. An absolute coverage group is a permanent...

  16. 20 CFR 404.1205 - Absolute coverage groups.

    Code of Federal Regulations, 2013 CFR

    2013-04-01

    ... 20 Employees' Benefits 2 2013-04-01 2013-04-01 false Absolute coverage groups. 404.1205 Section... INSURANCE (1950- ) Coverage of Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1205 Absolute coverage groups. (a) General. An absolute coverage group is a permanent...

  17. 20 CFR 404.1205 - Absolute coverage groups.

    Code of Federal Regulations, 2012 CFR

    2012-04-01

    ... 20 Employees' Benefits 2 2012-04-01 2012-04-01 false Absolute coverage groups. 404.1205 Section... INSURANCE (1950- ) Coverage of Employees of State and Local Governments What Groups of Employees May Be Covered § 404.1205 Absolute coverage groups. (a) General. An absolute coverage group is a permanent...

  18. Validation of the technique for absolute total electron content and differential code biases estimation

    NASA Astrophysics Data System (ADS)

    Mylnikova, Anna; Yasyukevich, Yury; Yasyukevich, Anna

    2017-04-01

    We have developed a technique for vertical total electron content (TEC) and differential code biases (DCBs) estimation using data from a single GPS/GLONASS station. The algorithm is based on TEC expansion into Taylor series in space and time (TayAbsTEC). We perform the validation of the technique using Global Ionospheric Maps (GIM) computed by Center for Orbit Determination in Europe (CODE) and Jet Propulsion Laboratory (JPL). We compared differences between absolute vertical TEC (VTEC) from GIM and VTEC evaluated by TayAbsTEC for 2009 year (solar activity minimum - sunspot number about 0), and for 2014 year (solar activity maximum - sunspot number 110). Since there is difference between VTEC from CODE and VTEC from JPL, we compare TayAbsTEC VTEC with both of them. We found that TayAbsTEC VTEC is closer to CODE VTEC than to JPL VTEC. The difference between TayAbsTEC VTEC and GIM VTEC is more noticeable for solar activity maximum (2014) than for solar activity minimum (2009) for both CODE and JPL. The distribution of VTEC differences is close to Gaussian distribution, so we conclude that results of TayAbsTEC are in the agreement with GIM VTEC. We also compared DCBs evaluated by TayAbsTEC and DCBs from GIM, computed by CODE. The TayAbsTEC DCBs are in good agreement with CODE DCBs for GPS satellites, but differ noticeable for GLONASS. We used DCBs to correct slant TEC to find out which DCBs give better results. Slant TEC correction with CODE DCBs produces negative and nonphysical TEC values. Slant TEC correction with TayAbsTEC DCBs doesn't produce such artifacts. The technique we developed is used for VTEC and DCBs calculation given only local GPS/GLONASS networks data. The evaluated VTEC data are in GIM framework which is handy when various data analyses are made.

  19. Electron- and proton-induced ionization of pyrimidine

    NASA Astrophysics Data System (ADS)

    Champion, Christophe; Quinto, Michele A.; Weck, Philippe F.

    2015-05-01

    The present work describes a quantum-mechanically based model of the electron- and proton-induced ionization of isolated pyrimidine molecules. The impact energies range from the target ionization threshold up to ~1 keV for electrons and from 10 keV up to 10 MeV for protons. The cross-section calculations are performed within the 1st Born approximation in which the ejected electron is described by a Coulomb wave whereas the incident and the scattered projectiles are both described by plane waves. The pyrimidine target is described using the Gaussian 09 software package. The theoretical predictions obtained are in good agreement with experimental absolute total cross sections, while large discrepancies are observed between existing semi-empirical models and the present calculations. Contribution to the Topical Issue "COST Action Nano-IBCT: Nano-scale Processes Behind Ion-Beam Cancer Therapy", edited by Andrey Solov'yov, Nigel Mason, Gustavo García, Eugene Surdutovich.

  20. Relativistic Electron Microburst Events: Modeling the Atmospheric Impact

    NASA Astrophysics Data System (ADS)

    Seppälä, A.; Douma, E.; Rodger, C. J.; Verronen, P. T.; Clilverd, M. A.; Bortnik, J.

    2018-01-01

    Relativistic electron microbursts are short-duration, high-energy precipitation events that are an important loss mechanism for radiation belt particles. Previous work to estimate their atmospheric impacts found no significant changes in atmospheric chemistry. Recent research on microbursts revealed that both the fluxes and frequency of microbursts are much higher than previously thought. We test the seasonal range of atmospheric impacts using this latest microburst information as input forcing to the Sodankylä Ion and Neutral Chemistry model. A modeled 6 h microburst storm increased mesospheric HOx by 15-25%/800-1,200% (summer/winter) and NOx by 1,500-2,250%/80-120%. Together, these drive 7-12%/12-20% upper mesospheric ozone losses, with a further 10-12% longer-term middle mesospheric loss during winter. Our results suggest that existing electron precipitation proxies, which do not yet take relativistic microburst energies into account, are likely missing a significant source of precipitation that contributes to atmospheric ozone balance.

  1. Concerning sources of O/1D/ in Aurora - Electron impact and dissociative recombination

    NASA Technical Reports Server (NTRS)

    Sharp, W. E.; Ortland, D.; Cageao, R.

    1983-01-01

    The present investigation is concerned with two questions. One is related to the possibility that the O(1D) level is produced by an as yet unidentified process in aurora. The second question is concerned with the need for an additional source and the altitude over which it is required. The data base of the AE satellite (AE-D in particular) was examined for this study. It is found that dissociative recombination and electron impact are inadequate sources of O(1D) in aurora. Nearly 90% of the source function is unidentified below 200 km and about 55% is missing above 250 km. The possibility that thermal electron impact could provide the missing source above 250 km was examined. Calculations showed that the missing source above 250 km could be explained by thermal electron impact if the electron temperatures were approximately 2900 K.

  2. Electron-impact excitation of the BΣ1u+ and CΠ1u electronic states of H2

    NASA Astrophysics Data System (ADS)

    Kato, H.; Kawahara, H.; Hoshino, M.; Tanaka, H.; Campbell, L.; Brunger, M. J.

    2008-06-01

    Differential and integral cross sections for electron-impact excitation of the dipole-allowed BΣ1u+ and CΠ1u electronic states of molecular hydrogen have been measured. The differential cross sections were determined by analysis of normalized energy-loss spectra obtained using a crossed-beam apparatus at the electron-impact energies of 40, 100, and 200 eV. Integral cross sections were subsequently derived from these data. The present work was undertaken in order to investigate some ambiguities between earlier experimental data and recent BEf-scaled cross sections as defined and calculated by Kim [J. Chem. Phys. 126, 064305 (2007)] and also to extend the energy range of the available data. Optical oscillator strengths, also determined as a part of the present investigation, were found to be in fair accordance with previous measurements and some calculations.

  3. Theory of electron-impact ionization of atoms

    NASA Astrophysics Data System (ADS)

    Kadyrov, A. S.; Mukhamedzhanov, A. M.; Stelbovics, A. T.; Bray, I.

    2004-12-01

    The existing formulations of electron-impact ionization of a hydrogenic target suffer from a number of formal problems including an ambiguous and phase-divergent definition of the ionization amplitude. An alternative formulation of the theory is given. An integral representation for the ionization amplitude which is free of ambiguity and divergence problems is derived and is shown to have four alternative, but equivalent, forms well suited for practical calculations. The extension to amplitudes of all possible scattering processes taking place in an arbitrary three-body system follows. A well-defined conventional post form of the breakup amplitude valid for arbitrary potentials including the long-range Coulomb interaction is given. Practical approaches are based on partial-wave expansions, so the formulation is also recast in terms of partial waves and partial-wave expansions of the asymptotic wave functions are presented. In particular, expansions of the asymptotic forms of the total scattering wave function, developed from both the initial and the final state, for electron-impact ionization of hydrogen are given. Finally, the utility of the present formulation is demonstrated on some well-known model problems.

  4. Control of secondary electrons from ion beam impact using a positive potential electrode

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Crowley, T. P., E-mail: tpcrowley@xanthotechnologies.com; Demers, D. R.; Fimognari, P. J.

    2016-11-15

    Secondary electrons emitted when an ion beam impacts a detector can amplify the ion beam signal, but also introduce errors if electrons from one detector propagate to another. A potassium ion beam and a detector comprised of ten impact wires, four split-plates, and a pair of biased electrodes were used to demonstrate that a low-voltage, positive electrode can be used to maintain the beneficial amplification effect while greatly reducing the error introduced from the electrons traveling between detector elements.

  5. A unitary convolution approximation for the impact-parameter dependent electronic energy loss

    NASA Astrophysics Data System (ADS)

    Schiwietz, G.; Grande, P. L.

    1999-06-01

    In this work, we propose a simple method to calculate the impact-parameter dependence of the electronic energy loss of bare ions for all impact parameters. This perturbative convolution approximation (PCA) is based on first-order perturbation theory, and thus, it is only valid for fast particles with low projectile charges. Using Bloch's stopping-power result and a simple scaling, we get rid of the restriction to low charge states and derive the unitary convolution approximation (UCA). Results of the UCA are then compared with full quantum-mechanical coupled-channel calculations for the impact-parameter dependent electronic energy loss.

  6. Absolute Summ

    NASA Astrophysics Data System (ADS)

    Phillips, Alfred, Jr.

    Summ means the entirety of the multiverse. It seems clear, from the inflation theories of A. Guth and others, that the creation of many universes is plausible. We argue that Absolute cosmological ideas, not unlike those of I. Newton, may be consistent with dynamic multiverse creations. As suggested in W. Heisenberg's uncertainty principle, and with the Anthropic Principle defended by S. Hawking, et al., human consciousness, buttressed by findings of neuroscience, may have to be considered in our models. Predictability, as A. Einstein realized with Invariants and General Relativity, may be required for new ideas to be part of physics. We present here a two postulate model geared to an Absolute Summ. The seedbed of this work is part of Akhnaton's philosophy (see S. Freud, Moses and Monotheism). Most important, however, is that the structure of human consciousness, manifest in Kenya's Rift Valley 200,000 years ago as Homo sapiens, who were the culmination of the six million year co-creation process of Hominins and Nature in Africa, allows us to do the physics that we do. .

  7. Absolute Sea-level Changes Derived from Integrated Geodetic Datasets (1955-2016) in the Caribbean Sea

    NASA Astrophysics Data System (ADS)

    Yang, L.; Wang, G.; Liu, H.

    2017-12-01

    Rising sea level has important direct impacts on coastal and island regions such as the Caribbean where the influence of sea-level rise is becoming more apparent. The Caribbean Sea is a semi-enclosed sea adjacent to the landmasses of South and Central America to the south and west, and the Greater Antilles and the Lesser Antilles separate it from the Atlantic Ocean to the north and east. The work focus on studying the relative and absolute sea-level changes by integrating tide gauge, GPS, and satellite altimetry datasets (1955-2016) within the Caribbean Sea. Further, the two main components of absolute sea-level change, ocean mass and steric sea-level changes, are respectively studied using GRACE, temperature, and salinity datasets (1955-2016). According to the analysis conducted, the sea-level change rates have considerable temporal and spatial variations, and estimates may be subject to the techniques used and observation periods. The average absolute sea-level rise rate is 1.8±0.3 mm/year for the period from 1955 to 2015 according to the integrated tide gauge and GPS observations; the average absolute sea-level rise rate is 3.5±0.6 mm/year for the period from 1993 to 2016 according to the satellite altimetry observations. This study shows that the absolute sea-level change budget in the Caribbean Sea is closed in the periods from 1955 to 2016, in which ocean mass change dominates the absolute sea-level rise. The absolute sea-level change budget is also closed in the periods from 2004 to 2016, in which steric sea-level rise dominates the absolute sea-level rise.

  8. Emmision cross section of OI (135.6nm) at 100 eV resulting from electron-inpact dissociative excitation of O-2

    NASA Technical Reports Server (NTRS)

    Noren, C.; Kanik, I.; Ajello, J.; McCartney, P.; Makarov, O.; McClintock, W.; Drake, V.

    2001-01-01

    In this Letter, we report for the first time, the ratio of the O I (135.6 nm)/O I (130.4 nm) absolute emission cross sections from electron-impact dissociative excitation of O-2 at 100 eV using facilities located at the University of Colorado, Laboratory for Atmospheric and Space Physics (LASP).

  9. Electron impact ionization of cycloalkanes, aldehydes, and ketones

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Gupta, Dhanoj; Antony, Bobby, E-mail: bka.ism@gmail.com

    The theoretical calculations of electron impact total ionization cross section for cycloalkane, aldehyde, and ketone group molecules are undertaken from ionization threshold to 2 keV. The present calculations are based on the spherical complex optical potential formalism and complex scattering potential ionization contribution method. The results of most of the targets studied compare fairly well with the recent measurements, wherever available and the cross sections for many targets are predicted for the first time. The correlation between the peak of ionization cross sections with number of target electrons and target parameters is also reported. It was found that the crossmore » sections at their maximum depend linearly with the number of target electrons and with other target parameters, confirming the consistency of the values reported here.« less

  10. Absolute optical metrology : nanometers to kilometers

    NASA Technical Reports Server (NTRS)

    Dubovitsky, Serge; Lay, O. P.; Peters, R. D.; Liebe, C. C.

    2005-01-01

    We provide and overview of the developments in the field of high-accuracy absolute optical metrology with emphasis on space-based applications. Specific work on the Modulation Sideband Technology for Absolute Ranging (MSTAR) sensor is described along with novel applications of the sensor.

  11. Electron impact ionization dynamics of para-benzoquinone

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Ali, E.; Ning, C. G.; Colgan, J.; Ingólfsson, O.; Madison, D. H.; Brunger, M. J.

    2016-10-01

    Triple differential cross sections (TDCSs) for the electron impact ionization of the unresolved combination of the 4 highest occupied molecular orbitals (4b3g, 5b2u, 1b1g, and 2b3u) of para-benzoquinone are reported. These were obtained in an asymmetric coplanar geometry with the scattered electron being observed at the angles -7.5°, -10.0°, -12.5° and -15.0°. The experimental cross sections are compared to theoretical calculations performed at the molecular 3-body distorted wave level, with a marginal level of agreement between them being found. The character of the ionized orbitals, through calculated momentum profiles, provides some qualitative interpretation for the measured angular distributions of the TDCS.

  12. Absolute Gravity Datum in the Age of Cold Atom Gravimeters

    NASA Astrophysics Data System (ADS)

    Childers, V. A.; Eckl, M. C.

    2014-12-01

    increase in accuracy. Our presentation will also explore the impact of such an instrument on our theory of how to constrain the gravity datum and on how to ensure stability, repeatability, and reproducibility across different absolute gravimeter systems.

  13. A global algorithm for estimating Absolute Salinity

    NASA Astrophysics Data System (ADS)

    McDougall, T. J.; Jackett, D. R.; Millero, F. J.; Pawlowicz, R.; Barker, P. M.

    2012-12-01

    The International Thermodynamic Equation of Seawater - 2010 has defined the thermodynamic properties of seawater in terms of a new salinity variable, Absolute Salinity, which takes into account the spatial variation of the composition of seawater. Absolute Salinity more accurately reflects the effects of the dissolved material in seawater on the thermodynamic properties (particularly density) than does Practical Salinity. When a seawater sample has standard composition (i.e. the ratios of the constituents of sea salt are the same as those of surface water of the North Atlantic), Practical Salinity can be used to accurately evaluate the thermodynamic properties of seawater. When seawater is not of standard composition, Practical Salinity alone is not sufficient and the Absolute Salinity Anomaly needs to be estimated; this anomaly is as large as 0.025 g kg-1 in the northernmost North Pacific. Here we provide an algorithm for estimating Absolute Salinity Anomaly for any location (x, y, p) in the world ocean. To develop this algorithm, we used the Absolute Salinity Anomaly that is found by comparing the density calculated from Practical Salinity to the density measured in the laboratory. These estimates of Absolute Salinity Anomaly however are limited to the number of available observations (namely 811). In order to provide a practical method that can be used at any location in the world ocean, we take advantage of approximate relationships between Absolute Salinity Anomaly and silicate concentrations (which are available globally).

  14. Integral cross sections for electron impact excitation of electronic states of N2

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.; Nolan, A. M.; Kelly, L. J.; Wedding, A. B.; Harrison, J.; Teubner, P. J. O.; Cartwright, D. C.; McLaughlin, B.

    2001-04-01

    We report integral cross sections (ICSs) for electron impact excitation of the A 3Σ+u, B 3Πg, W 3Δu, B' 3Σ-u, a' 1Σ-u, a 1Πg, ω1Δu, C 3Πu, E 3Σ+g and a'' 1Σ+g electronic states of N2. The present data, for each state, were derived at five incident electron energies in the range 15-50 eV, from the earlier crossed-beam differential cross section (DCS) measurements of our group. This was facilitated by using a molecular phase shift analysis technique to extrapolate the measured DCSs to 0° and 180°, before performing the integration. A comprehensive comparison of the present ICSs with the results of earlier experimental studies, both crossed beam and electron swarm, and theoretical calculations is provided. This comparison clearly indicates that some of the previous estimates for these excited electronic-state cross sections need to be reassessed. In addition, we have used the present ICSs in a Monte Carlo simulation for modelling the behaviour of an electron swarm in the bulk of a low current N2 discharge. The macroscopic transport parameters determined from this simulation are compared against those measured from independent swarm-based experiments and the self-consistency of our ICSs evaluated.

  15. Absolute instability of the Gaussian wake profile

    NASA Technical Reports Server (NTRS)

    Hultgren, Lennart S.; Aggarwal, Arun K.

    1987-01-01

    Linear parallel-flow stability theory has been used to investigate the effect of viscosity on the local absolute instability of a family of wake profiles with a Gaussian velocity distribution. The type of local instability, i.e., convective or absolute, is determined by the location of a branch-point singularity with zero group velocity of the complex dispersion relation for the instability waves. The effects of viscosity were found to be weak for values of the wake Reynolds number, based on the center-line velocity defect and the wake half-width, larger than about 400. Absolute instability occurs only for sufficiently large values of the center-line wake defect. The critical value of this parameter increases with decreasing wake Reynolds number, thereby indicating a shrinking region of absolute instability with decreasing wake Reynolds number. If backflow is not allowed, absolute instability does not occur for wake Reynolds numbers smaller than about 38.

  16. Electron-impact ionization of Ne (2 p ) and Ar (3 p ) at intermediate energies: Role of the postcollision interaction

    NASA Astrophysics Data System (ADS)

    Hu, Xiaoqing; Gao, Cong-Zhang; Chen, Zhanbin; Wang, Jianguo; Wu, Yong; Wang, Yang

    2017-11-01

    We present the absolute triple differential cross section (TDCS) for single ionization of Ne (2 p ) at an impact energy of 599.6 eV and Ar (3 p ) at 195 eV. The role of the postcollision interaction (PCI) is studied using a high-order distorted-wave Born approximation model with a continuum distorted-waves expansion. Both the second- and third-order effects are considered in the present calculations, and the third-order distorted wave Born approximation model is reported in the (e ,2 e ) reaction. The calculated results show satisfactory agreement with experimental data. The magnitude of the absolute TDCS is enhanced by a factor 2-3 when the strength factor γ of the PCI amplitude is summarized just from 0 to 2. This proves that the PCI plays an important role in the absolute TDCS of the (e ,2 e ) reaction in the intermediate-energy region.

  17. 49 CFR 236.709 - Block, absolute.

    Code of Federal Regulations, 2010 CFR

    2010-10-01

    ... 49 Transportation 4 2010-10-01 2010-10-01 false Block, absolute. 236.709 Section 236.709 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Block, absolute. A block in which no train is permitted to enter while it is occupied by another train. ...

  18. 49 CFR 236.709 - Block, absolute.

    Code of Federal Regulations, 2011 CFR

    2011-10-01

    ... 49 Transportation 4 2011-10-01 2011-10-01 false Block, absolute. 236.709 Section 236.709 Transportation Other Regulations Relating to Transportation (Continued) FEDERAL RAILROAD ADMINISTRATION... Block, absolute. A block in which no train is permitted to enter while it is occupied by another train. ...

  19. Calculating Absolute Transition Probabilities for Deformed Nuclei in the Rare-Earth Region

    NASA Astrophysics Data System (ADS)

    Stratman, Anne; Casarella, Clark; Aprahamian, Ani

    2017-09-01

    Absolute transition probabilities are the cornerstone of understanding nuclear structure physics in comparison to nuclear models. We have developed a code to calculate absolute transition probabilities from measured lifetimes, using a Python script and a Mathematica notebook. Both of these methods take pertinent quantities such as the lifetime of a given state, the energy and intensity of the emitted gamma ray, and the multipolarities of the transitions to calculate the appropriate B(E1), B(E2), B(M1) or in general, any B(σλ) values. The program allows for the inclusion of mixing ratios of different multipolarities and the electron conversion of gamma-rays to correct for their intensities, and yields results in absolute units or results normalized to Weisskopf units. The code has been tested against available data in a wide range of nuclei from the rare earth region (28 in total), including 146-154Sm, 154-160Gd, 158-164Dy, 162-170Er, 168-176Yb, and 174-182Hf. It will be available from the Notre Dame Nuclear Science Laboratory webpage for use by the community. This work was supported by the University of Notre Dame College of Science, and by the National Science Foundation, under Contract PHY-1419765.

  20. Observation of two-center interference effects for electron impact ionization of N2

    NASA Astrophysics Data System (ADS)

    Chaluvadi, Hari; Nur Ozer, Zehra; Dogan, Mevlut; Ning, Chuangang; Colgan, James; Madison, Don

    2015-08-01

    In 1966, Cohen and Fano (1966 Phys. Rev. 150 30) suggested that one should be able to observe the equivalent of Young’s double slit interference if the double slits were replaced by a diatomic molecule. This suggestion inspired many experimental and theoretical studies searching for double slit interference effects both for photon and particle ionization of diatomic molecules. These effects turned out to be so small for particle ionization that this work proceeded slowly and evidence for interference effects were only found by looking at cross section ratios. Most of the early particle work concentrated on double differential cross sections for heavy particle scattering and the first evidence for two-center interference for electron-impact triple differential cross section (TDCS) did not appear until 2006 for ionization of H2. Subsequent work has now firmly established that two-center interference effects can be seen in the TDCS for electron-impact ionization of H2. However, in spite of several experimental and theoretical studies, similar effects have not been found for electron-impact ionization of N2. Here we report the first evidence for two-center interference for electron-impact ionization of N2.

  1. Absolute quantification of microbial taxon abundances.

    PubMed

    Props, Ruben; Kerckhof, Frederiek-Maarten; Rubbens, Peter; De Vrieze, Jo; Hernandez Sanabria, Emma; Waegeman, Willem; Monsieurs, Pieter; Hammes, Frederik; Boon, Nico

    2017-02-01

    High-throughput amplicon sequencing has become a well-established approach for microbial community profiling. Correlating shifts in the relative abundances of bacterial taxa with environmental gradients is the goal of many microbiome surveys. As the abundances generated by this technology are semi-quantitative by definition, the observed dynamics may not accurately reflect those of the actual taxon densities. We combined the sequencing approach (16S rRNA gene) with robust single-cell enumeration technologies (flow cytometry) to quantify the absolute taxon abundances. A detailed longitudinal analysis of the absolute abundances resulted in distinct abundance profiles that were less ambiguous and expressed in units that can be directly compared across studies. We further provide evidence that the enrichment of taxa (increase in relative abundance) does not necessarily relate to the outgrowth of taxa (increase in absolute abundance). Our results highlight that both relative and absolute abundances should be considered for a comprehensive biological interpretation of microbiome surveys.

  2. Absolute Radiation Measurements in Earth and Mars Entry Conditions

    NASA Technical Reports Server (NTRS)

    Cruden, Brett A.

    2014-01-01

    This paper reports on the measurement of radiative heating for shock heated flows which simulate conditions for Mars and Earth entries. Radiation measurements are made in NASA Ames' Electric Arc Shock Tube at velocities from 3-15 km/s in mixtures of N2/O2 and CO2/N2/Ar. The technique and limitations of the measurement are summarized in some detail. The absolute measurements will be discussed in regards to spectral features, radiative magnitude and spatiotemporal trends. Via analysis of spectra it is possible to extract properties such as electron density, and rotational, vibrational and electronic temperatures. Relaxation behind the shock is analyzed to determine how these properties relax to equilibrium and are used to validate and refine kinetic models. It is found that, for some conditions, some of these values diverge from non-equilibrium indicating a lack of similarity between the shock tube and free flight conditions. Possible reasons for this are discussed.

  3. Electron Impact Ionization: A New Parameterization for 100 eV to 1 MeV Electrons

    NASA Technical Reports Server (NTRS)

    Fang, Xiaohua; Randall, Cora E.; Lummerzheim, Dirk; Solomon, Stanley C.; Mills, Michael J.; Marsh, Daniel; Jackman, Charles H.; Wang, Wenbin; Lu, Gang

    2008-01-01

    Low, medium and high energy electrons can penetrate to the thermosphere (90-400 km; 55-240 miles) and mesosphere (50-90 km; 30-55 miles). These precipitating electrons ionize that region of the atmosphere, creating positively charged atoms and molecules and knocking off other negatively charged electrons. The precipitating electrons also create nitrogen-containing compounds along with other constituents. Since the electron precipitation amounts change within minutes, it is necessary to have a rapid method of computing the ionization and production of nitrogen-containing compounds for inclusion in computationally-demanding global models. A new methodology has been developed, which has parameterized a more detailed model computation of the ionizing impact of precipitating electrons over the very large range of 100 eV up to 1,000,000 eV. This new parameterization method is more accurate than a previous parameterization scheme, when compared with the more detailed model computation. Global models at the National Center for Atmospheric Research will use this new parameterization method in the near future.

  4. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; da Costa, R. F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; Blanco, F.; García, G.; Brunger, M. J.

    2016-04-01

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20-250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arise due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron-furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.

  5. Two-potential approach for electron-molecular collisions at intermediate and high energies - Application to e-N2 scatterings

    NASA Technical Reports Server (NTRS)

    Choi, B. H.; Poe, R. T.; Sun, J. C.; Shan, Y.

    1979-01-01

    A general theoretical approach is proposed for the calculation of elastic, vibrational, and rotational transitions for electron-molecule scattering at intermediate and high-electron-impact energies. In this formulation, contributions to the scattering process come from the incoherent sum of two dominant potentials: a short-range shielded nuclear Coulomb potential from individual atomic centers, and a permanent/induced long-range potential. Application to e-N2 scattering from 50-500 eV incident electron energies has yielded good agreement with absolutely calibrated experiments. Comparisons with other theoretical approaches are made. The physical picture as well as the general features of electron-molecule scattering process are discussed within the framework of the two-potential approach.

  6. Absolute Humidity and the Seasonality of Influenza (Invited)

    NASA Astrophysics Data System (ADS)

    Shaman, J. L.; Pitzer, V.; Viboud, C.; Grenfell, B.; Goldstein, E.; Lipsitch, M.

    2010-12-01

    Much of the observed wintertime increase of mortality in temperate regions is attributed to seasonal influenza. A recent re-analysis of laboratory experiments indicates that absolute humidity strongly modulates the airborne survival and transmission of the influenza virus. Here we show that the onset of increased wintertime influenza-related mortality in the United States is associated with anomalously low absolute humidity levels during the prior weeks. We then use an epidemiological model, in which observed absolute humidity conditions temper influenza transmission rates, to successfully simulate the seasonal cycle of observed influenza-related mortality. The model results indicate that direct modulation of influenza transmissibility by absolute humidity alone is sufficient to produce this observed seasonality. These findings provide epidemiological support for the hypothesis that absolute humidity drives seasonal variations of influenza transmission in temperate regions. In addition, we show that variations of the basic and effective reproductive numbers for influenza, caused by seasonal changes in absolute humidity, are consistent with the general timing of pandemic influenza outbreaks observed for 2009 A/H1N1 in temperate regions. Indeed, absolute humidity conditions correctly identify the region of the United States vulnerable to a third, wintertime wave of pandemic influenza. These findings suggest that the timing of pandemic influenza outbreaks is controlled by a combination of absolute humidity conditions, levels of susceptibility and changes in population mixing and contact rates.

  7. Electron Impact K-shell Ionization of Atomic Targets

    NASA Astrophysics Data System (ADS)

    Saha, Bidhan; Basak, Arun K.; Alfaz Uddin, M.; Patoary, A. A. R.

    2008-05-01

    In spite of considerable progress -both theoretically and experimentally- recently in evaluating accurate K-shell ionization cross sections that play a decisive role for quantitative analyses using (i) electron probe microanalysis, (ii) Auger electron spectroscopy and (iii) electron energy loss spectra, attempts are still continuing to search for a model that can easily generate reliable cross sections for a wide range of energies and for various targets needed for plasma modeling code We report few modifications of the widely used binary encounter approximation (BEA) [1,2] and have tested by evaluating the electron impact K-shell ionization of few neutral targets at various projectile energies. Details will be presented at the meeting. [1] M. Gryziniski, Phys. Rev. A 138, 336 (1965); [2] L. Vriens, Proc. Phys. Soc. (London) 89, 13, (1966). [3M. A. Uddin , A. K. F. Haque, M. M. Billah, A. K. Basak, K, R, Karim and B. C. Saha, ,Phys. Rev. A 71,032715 (2005); [4] M. A. Uddin, A. K. Basak, and B. C. Saha, Int. J. Quan. Chem 100, 184 (2004).

  8. Low absolute neutrophil counts in African infants.

    PubMed

    Kourtis, Athena P; Bramson, Brian; van der Horst, Charles; Kazembe, Peter; Ahmed, Yusuf; Chasela, Charles; Hosseinipour, Mina; Knight, Rodney; Lugalia, Lebah; Tegha, Gerald; Joaki, George; Jafali, Robert; Jamieson, Denise J

    2005-07-01

    Infants of African origin have a lower normal range of absolute neutrophil counts than white infants; this fact, however, remains under appreciated by clinical researchers in the United States. During the initial stages of a clinical trial in Malawi, the authors noted an unexpectedly high number of infants with absolute neutrophil counts that would be classifiable as neutropenic using the National Institutes of Health's Division of AIDS toxicity tables. The authors argue that the relevant Division of AIDS table does not take into account the available evidence of low absolute neutrophil counts in African infants and that a systematic collection of data from many African settings might help establish the absolute neutrophil count cutpoints to be used for defining neutropenia in African populations.

  9. Absolute colorimetric characterization of a DSLR camera

    NASA Astrophysics Data System (ADS)

    Guarnera, Giuseppe Claudio; Bianco, Simone; Schettini, Raimondo

    2014-03-01

    A simple but effective technique for absolute colorimetric camera characterization is proposed. It offers a large dynamic range requiring just a single, off-the-shelf target and a commonly available controllable light source for the characterization. The characterization task is broken down in two modules, respectively devoted to absolute luminance estimation and to colorimetric characterization matrix estimation. The characterized camera can be effectively used as a tele-colorimeter, giving an absolute estimation of the XYZ data in cd=m2. The user is only required to vary the f - number of the camera lens or the exposure time t, to better exploit the sensor dynamic range. The estimated absolute tristimulus values closely match the values measured by a professional spectro-radiometer.

  10. The Cosmological Impact of AGN Outflows: Measuring Absolute Abundances and Kinetic Luminosities

    NASA Astrophysics Data System (ADS)

    Arav, Nahum

    2009-07-01

    AGN outflows are increasingly invoked as a major contributor to the formation and evolution of supermassive black holes, their host galaxies, the surrounding IGM, and cluster cooling flows. Our HST/COS proposal will determine reliable absolute chemical abundances in six AGN outflows, which influences several of the processes mentioned above. To date there is only one such determination, done by our team on Mrk 279 using 16 HST/STIS orbits and 100 ksec of FUSE time. The advent of COS and its high sensitivity allows us to choose among fainter objects at redshifts high enough to preclude the need for FUSE. This will allow us to determine the absolute abundances for six AGN {all fainter than Mrk 279} using only 40 HST COS orbits. This will put abundances studies in AGN on a firm footing, an elusive goal for the past four decades. In addition, prior FUSE observations of four of these targets indicate that it is probable that the COS observations will detect troughs from excited levels of C III. These will allow us to measure the distances of the outflows and thereby determine their kinetic luminosity, a major goal in AGN feedback research. We will use our state of the art column density extraction methods and velocity-dependent photoionization models to determine the abundances and kinetic luminosity. Previous AGN outflow projects suffered from the constraints of deciding what science we could do using ONE of the handful of bright targets that were observable. With COS we can choose the best sample for our experiment. As an added bonus, most of the spectral range of our targets has not been observed previously, greatly increasing the discovery phase space.

  11. A generalized population dynamics model for reproductive interference with absolute density dependence.

    PubMed

    Kyogoku, Daisuke; Sota, Teiji

    2017-05-17

    Interspecific mating interactions, or reproductive interference, can affect population dynamics, species distribution and abundance. Previous population dynamics models have assumed that the impact of frequency-dependent reproductive interference depends on the relative abundances of species. However, this assumption could be an oversimplification inappropriate for making quantitative predictions. Therefore, a more general model to forecast population dynamics in the presence of reproductive interference is required. Here we developed a population dynamics model to describe the absolute density dependence of reproductive interference, which appears likely when encounter rate between individuals is important. Our model (i) can produce diverse shapes of isoclines depending on parameter values and (ii) predicts weaker reproductive interference when absolute density is low. These novel characteristics can create conditions where coexistence is stable and independent from the initial conditions. We assessed the utility of our model in an empirical study using an experimental pair of seed beetle species, Callosobruchus maculatus and Callosobruchus chinensis. Reproductive interference became stronger with increasing total beetle density even when the frequencies of the two species were kept constant. Our model described the effects of absolute density and showed a better fit to the empirical data than the existing model overall.

  12. Electron Impact Studies Relevant to Rosetta Coma Measurements of 67P/Churyumov-Gerasimenko

    NASA Astrophysics Data System (ADS)

    Bodewits, D.; Feldman, P. D.; Matejčík, Š.; Országh, J.; Durian, M.

    2017-12-01

    Auroral emission from electron impact processes can provide a remote window on the physical properties of plasma and neutral gases surrounding small bodies (Galand & Chakrabarti, 2002; Roth et al. 2014). Surprisingly, Rosetta found that outside 2 AU pre-perihelion, atomic and molecular emission features in the inner coma were predominantly caused by dissociative electron impact excitation (Feldman et al. 2015). When the comet came within 2 au of the Sun, fluorescent emission became the dominant process, as water densities in the inner coma could effectively cool the electron population below the appearance energy of the relevant electron impact dissociative excitation processes (Bodewits et al. 2016). Further quantitative interpretation of the Alice and OSIRIS images of the coma is by limited excitation cross sections measured of electron impact reactions with the gases present in cometary comae, including H2O, CO2, CO, O2, and HCN. We will present the first results of a series of experiments dedicated to investigate the emission features seen by the instruments on board Rosetta. The experimental set up is located at the Comenius University in Bratislava, Slovakia, and consists of a crossed-beam configuration combining an electron monochromator and a gas beam (Danko et al. 2013). The electron induced emission spectra are measured using a Czerny-Turner optical monochromator provides a spectral resolution of 0.3 nm FWHM and is equipped with a photomultiplier sensitive between 185 and 710 nm. References: Bodewits, D. et al. The Astronomical Journal 152, 130 (2016). Danko, M. et al. J. Phys. B 46, 045203 (2013). Feldman, P. D. et al. Astron. Astroph. 583, A8 (2015). Galand, M. & Chakrabarti, S. Geophysical Monograph 130. Ed. Michael Mendillo 130, 55- (2002). Roth, L., Saur, J., Retherford, K. D., Strobel, D. F. & Feldman, P. D. Science (2014). doi:10.1126/science.1247051

  13. Cryogenic, Absolute, High Pressure Sensor

    NASA Technical Reports Server (NTRS)

    Chapman, John J. (Inventor); Shams. Qamar A. (Inventor); Powers, William T. (Inventor)

    2001-01-01

    A pressure sensor is provided for cryogenic, high pressure applications. A highly doped silicon piezoresistive pressure sensor is bonded to a silicon substrate in an absolute pressure sensing configuration. The absolute pressure sensor is bonded to an aluminum nitride substrate. Aluminum nitride has appropriate coefficient of thermal expansion for use with highly doped silicon at cryogenic temperatures. A group of sensors, either two sensors on two substrates or four sensors on a single substrate are packaged in a pressure vessel.

  14. Absolute Income, Relative Income, and Happiness

    ERIC Educational Resources Information Center

    Ball, Richard; Chernova, Kateryna

    2008-01-01

    This paper uses data from the World Values Survey to investigate how an individual's self-reported happiness is related to (i) the level of her income in absolute terms, and (ii) the level of her income relative to other people in her country. The main findings are that (i) both absolute and relative income are positively and significantly…

  15. Simple and universal model for electron-impact ionization of complex biomolecules

    NASA Astrophysics Data System (ADS)

    Tan, Hong Qi; Mi, Zhaohong; Bettiol, Andrew A.

    2018-03-01

    We present a simple and universal approach to calculate the total ionization cross section (TICS) for electron impact ionization in DNA bases and other biomaterials in the condensed phase. Evaluating the electron impact TICS plays a vital role in ion-beam radiobiology simulation at the cellular level, as secondary electrons are the main cause of DNA damage in particle cancer therapy. Our method is based on extending the dielectric formalism. The calculated results agree well with experimental data and show a good comparison with other theoretical calculations. This method only requires information of the chemical composition and density and an estimate of the mean binding energy to produce reasonably accurate TICS of complex biomolecules. Because of its simplicity and great predictive effectiveness, this method could be helpful in situations where the experimental TICS data are absent or scarce, such as in particle cancer therapy.

  16. Universal Cosmic Absolute and Modern Science

    NASA Astrophysics Data System (ADS)

    Kostro, Ludwik

    The official Sciences, especially all natural sciences, respect in their researches the principle of methodic naturalism i.e. they consider all phenomena as entirely natural and therefore in their scientific explanations they do never adduce or cite supernatural entities and forces. The purpose of this paper is to show that Modern Science has its own self-existent, self-acting, and self-sufficient Natural All-in Being or Omni-Being i.e. the entire Nature as a Whole that justifies the scientific methodic naturalism. Since this Natural All-in Being is one and only It should be considered as the own scientifically justified Natural Absolute of Science and should be called, in my opinion, the Universal Cosmic Absolute of Modern Science. It will be also shown that the Universal Cosmic Absolute is ontologically enormously stratified and is in its ultimate i.e. in its most fundamental stratum trans-reistic and trans-personal. It means that in its basic stratum. It is neither a Thing or a Person although It contains in Itself all things and persons with all other sentient and conscious individuals as well, On the turn of the 20th century the Science has begun to look for a theory of everything, for a final theory, for a master theory. In my opinion the natural Universal Cosmic Absolute will constitute in such a theory the radical all penetrating Ultimate Basic Reality and will substitute step by step the traditional supernatural personal Absolute.

  17. Jasminum sambac flower absolutes from India and China--geographic variations.

    PubMed

    Braun, Norbert A; Sim, Sherina

    2012-05-01

    Seven Jasminum sambac flower absolutes from different locations in the southern Indian state of Tamil Nadu were analyzed using GC and GC-MS. Focus was placed on 41 key ingredients to investigate geographic variations in this species. These seven absolutes were compared with an Indian bud absolute and commercially available J. sambac flower absolutes from India and China. All absolutes showed broad variations for the 10 main ingredients between 8% and 96%. In addition, the odor of Indian and Chinese J. sambac flower absolutes were assessed.

  18. Advancing Absolute Calibration for JWST and Other Applications

    NASA Astrophysics Data System (ADS)

    Rieke, George; Bohlin, Ralph; Boyajian, Tabetha; Carey, Sean; Casagrande, Luca; Deustua, Susana; Gordon, Karl; Kraemer, Kathleen; Marengo, Massimo; Schlawin, Everett; Su, Kate; Sloan, Greg; Volk, Kevin

    2017-10-01

    We propose to exploit the unique optical stability of the Spitzer telescope, along with that of IRAC, to (1) transfer the accurate absolute calibration obtained with MSX on very bright stars directly to two reference stars within the dynamic range of the JWST imagers (and of other modern instrumentation); (2) establish a second accurate absolute calibration based on the absolutely calibrated spectrum of the sun, transferred onto the astronomical system via alpha Cen A; and (3) provide accurate infrared measurements for the 11 (of 15) highest priority stars with no such data but with accurate interferometrically measured diameters, allowing us to optimize determinations of effective temperatures using the infrared flux method and thus to extend the accurate absolute calibration spectrally. This program is integral to plans for an accurate absolute calibration of JWST and will also provide a valuable Spitzer legacy.

  19. Absolute radiometric calibration of advanced remote sensing systems

    NASA Technical Reports Server (NTRS)

    Slater, P. N.

    1982-01-01

    The distinction between the uses of relative and absolute spectroradiometric calibration of remote sensing systems is discussed. The advantages of detector-based absolute calibration are described, and the categories of relative and absolute system calibrations are listed. The limitations and problems associated with three common methods used for the absolute calibration of remote sensing systems are addressed. Two methods are proposed for the in-flight absolute calibration of advanced multispectral linear array systems. One makes use of a sun-illuminated panel in front of the sensor, the radiance of which is monitored by a spectrally flat pyroelectric radiometer. The other uses a large, uniform, high-radiance reference ground surface. The ground and atmospheric measurements required as input to a radiative transfer program to predict the radiance level at the entrance pupil of the orbital sensor are discussed, and the ground instrumentation is described.

  20. Emission- and fluorescence-spectroscopic investigation of a glow discharge plasma: absolute number density of radiative and nonradiative atoms in the negative glow.

    PubMed

    Takubo, Y; Sato, T; Asaoka, N; Kusaka, K; Akiyama, T; Muroo, K; Yamamoto, M

    2008-01-01

    The excited-state atom densities in the negative glow of a direct-current glow discharge are derived from the spectral-line intensity of radiative atoms and the resonance-fluorescence photon flux of nonradiative atoms. The discharge is operated in a helium-argon gas mixture (molar fraction ratio 91:9; total gas pressure 5 Torr) at a dc current of 0.7-1.2 mA. The observations are made in the region of the maximum luminance in the cathode region, where high-energy electrons accelerated in the cathode fall are injected into the negative glow. The emission intensities of the He I, He II, Ar I, and Ar II spectral lines are measured with a calibrated tungsten ribbon lamp as an absolute spectral-radiance standard. Fluorescence photons scattered by helium and argon atoms in the metastable state and argon atoms in the resonance state are detected by the laser-induced fluorescence (LIF) method with the Rayleigh scattering of nitrogen molecules as an absolute standard of scattering cross section. The laser absorption method is incorporated to confirm the result of the LIF measurement. Excitation energies of the measured spectral lines range from 11.6 (Ar I) to 75.6 eV (He II), where the excitation energy is measured from the ground state of the neutral atom on the assumption that, in the plasma of this study, both the neutral and the ionic lines are excited by electron impact in a single-step process from the ground state of the corresponding neutral atoms. Experimental evidence is shown for the validity of this assumption.

  1. The influence of music-elicited emotions and relative pitch on absolute pitch memory for familiar melodies.

    PubMed

    Jakubowski, Kelly; Müllensiefen, Daniel

    2013-01-01

    Levitin's findings that nonmusicians could produce from memory the absolute pitches of self-selected pop songs have been widely cited in the music psychology literature. These findings suggest that latent absolute pitch (AP) memory may be a more widespread trait within the population than traditional AP labelling ability. However, it has been left unclear what factors may facilitate absolute pitch retention for familiar pieces of music. The aim of the present paper was to investigate factors that may contribute to latent AP memory using Levitin's sung production paradigm for AP memory and comparing results to the outcomes of a pitch labelling task, a relative pitch memory test, measures of music-induced emotions, and various measures of participants' musical backgrounds. Our results suggest that relative pitch memory and the quality and degree of music-elicited emotions impact on latent AP memory.

  2. Electron Impact Multiple Ionization Cross Sections for Solar Physics

    NASA Astrophysics Data System (ADS)

    Hahn, M.; Savin, D. W.; Mueller, A.

    2017-12-01

    We have compiled a set of electron-impact multiple ionization (EIMI) cross sections for astrophysically relevant ions. EIMI can have a significant effect on the ionization balance of non-equilibrium plasmas. For example, it can be important if there is a rapid change in the electron temperature, as in solar flares or in nanoflare coronal heating. EIMI is also likely to be significant when the electron energy distribution is non-thermal, such as if the electrons follow a kappa distribution. Cross sections for EIMI are needed in order to account for these processes in plasma modeling and for spectroscopic interpretation. Here, we describe our comparison of proposed semiempirical formulae to the available experimental EIMI cross section data. Based on this comparison, we have interpolated and extrapolated fitting parameters to systems that have not yet been measured. A tabulation of the fit parameters is provided for thousands of EIMI cross sections. We also highlight some outstanding issues that remain to be resolved.

  3. Impact of Electronic Portfolios on Prospective Teachers' Participation, Motivation, and Autonomous Learning

    ERIC Educational Resources Information Center

    Gámiz-Sánchez, Vanesa-María; Gallego-Arrufat, María-Jesús; Crisol-Moya, Emilio

    2016-01-01

    This study explores the impact of electronic portfolios on undergraduate learning in higher education. Based on a descriptive study, it analyses the prospective teacher's perception of use of these tools (electronic portfolio in Moodle-Mahara, in the institutional environment of a university in southern Europe), examining the variables…

  4. Experimental and theoretical triple differential cross sections for electron-impact ionization of Ar (3p) for equal energy final state electrons

    NASA Astrophysics Data System (ADS)

    Amami, Sadek; Ozer, Zehra N.; Dogan, Mevlut; Yavuz, Murat; Varol, Onur; Madison, Don

    2016-09-01

    There have been several studies of electron-impact ionization of inert gases for asymmetric final state energy sharing and normally one electron has an energy significantly higher than the other. However, there have been relatively few studies examining equal energy final state electrons. Here we report experimental and theoretical triple differential cross sections for electron impact ionization of Ar (3p) for equal energy sharing of the outgoing electrons. Previous experimental results combined with some new measurements are compared with distorted wave born approximation (DWBA) results, DWBA results using the Ward-Macek (WM) approximation for the post collision interaction (PCI), and three-body distorted wave (3DW) which includes PCI without approximation. The results show that it is crucially important to include PCI in the calculation particularly for lower energies and that the WM approximation is valid only for high energies. The 3DW, on the other hand, is in reasonably good agreement with data down to fairly low energies.

  5. Influence of renormalization shielding on the electron-impact ionization process in dense partially ionized plasmas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Song, Mi-Young; Yoon, Jung-Sik; Jung, Young-Dae, E-mail: ydjung@hanyang.ac.kr

    2015-04-15

    The renormalization shielding effects on the electron-impact ionization of hydrogen atom are investigated in dense partially ionized plasmas. The effective projectile-target interaction Hamiltonian and the semiclassical trajectory method are employed to obtain the transition amplitude as well as the ionization probability as functions of the impact parameter, the collision energy, and the renormalization parameter. It is found that the renormalization shielding effect suppresses the transition amplitude for the electron-impact ionization process in dense partially ionized plasmas. It is also found that the renormalization effect suppresses the differential ionization cross section in the peak impact parameter region. In addition, it ismore » found that the influence of renormalization shielding on the ionization cross section decreases with an increase of the relative collision energy. The variations of the renormalization shielding effects on the electron-impact ionization cross section are also discussed.« less

  6. Absolute atomic hydrogen densities in a radio frequency discharge measured by two-photon laser induced fluorescence imaging

    NASA Astrophysics Data System (ADS)

    Chérigier, L.; Czarnetzki, U.; Luggenhölscher, D.; Schulz-von der Gathen, V.; Döbele, H. F.

    1999-01-01

    Absolute atomic hydrogen densities were measured in the gaseous electronics conference reference cell parallel plate reactor by Doppler-free two-photon absorption laser induced fluorescence spectroscopy (TALIF) at λ=205 nm. The capacitively coupled radio frequency discharge was operated at 13.56 MHz in pure hydrogen under various input power and pressure conditions. The Doppler-free excitation technique with an unfocused laser beam together with imaging the fluorescence radiation by an intensified charge coupled device camera allows instantaneous spatial resolution along the radial direction. Absolute density calibration is obtained with the aid of a flow tube reactor and titration with NO2. The influence of spatial intensity inhomogenities along the laser beam and subsequent fluorescence are corrected by TALIF in xenon. A full mapping of the absolute density distribution between the electrodes was obtained. The detection limit for atomic hydrogen amounts to about 2×1018 m-3. The dissociation degree is of the order of a few percent.

  7. Electron impact excitation coefficients for laboratory and astrophysical plasmas

    NASA Technical Reports Server (NTRS)

    Davis, J.; Kepple, P. C.; Blaha, M.

    1976-01-01

    Electron impact excitation rate coefficients have been obtained for a number of transitions in highly ionized ions of interest to astrophysical and laboratory plasmas. The calculations were done using the method of distorted waves. Results are presented for various transitions in highly ionized Ne, Na, Al, Si, A, Ca, Ni and Fe.

  8. Application of the BEf-scaling approach to electron impact excitation of diople-allowed electronic states in molecules

    NASA Astrophysics Data System (ADS)

    Brunger, M. J.; Thorn, P. A.; Campbell, L.; Kato, H.; Kawahara, H.; Hoshino, M.; Tanaka, H.; Kim, Y.-K.

    2008-05-01

    We consider the efficacy of the BEf-scaling approach, in calculating reliable integral cross sections for electron impact excitation of dipole-allowed electronic states in molecules. We will demonstrate, using specific examples in H2, CO and H2O, that this relatively simple procedure can generate quite accurate integral cross sections which compare well with available experimental data. Finally, we will briefly consider the ramifications of this to atmospheric and other types of modelling studies.

  9. Linking Comparisons of Absolute Gravimeters: A Proof of Concept for a new Global Absolute Gravity Reference System.

    NASA Astrophysics Data System (ADS)

    Wziontek, H.; Palinkas, V.; Falk, R.; Vaľko, M.

    2016-12-01

    Since decades, absolute gravimeters are compared on a regular basis on an international level, starting at the International Bureau for Weights and Measures (BIPM) in 1981. Usually, these comparisons are based on constant reference values deduced from all accepted measurements acquired during the comparison period. Temporal changes between comparison epochs are usually not considered. Resolution No. 2, adopted by IAG during the IUGG General Assembly in Prague 2015, initiates the establishment of a Global Absolute Gravity Reference System based on key comparisons of absolute gravimeters (AG) under the International Committee for Weights and Measures (CIPM) in order to establish a common level in the microGal range. A stable and unique reference frame can only be achieved, if different AG are taking part in different kind of comparisons. Systematic deviations between the respective comparison reference values can be detected, if the AG can be considered stable over time. The continuous operation of superconducting gravimeters (SG) on selected stations further supports the temporal link of comparison reference values by establishing a reference function over time. By a homogenous reprocessing of different comparison epochs and including AG and SG time series at selected stations, links between several comparisons will be established and temporal comparison reference functions will be derived. By this, comparisons on a regional level can be traced to back to the level of key comparisons, providing a reference for other absolute gravimeters. It will be proved and discussed, how such a concept can be used to support the future absolute gravity reference system.

  10. Absolute dose calculations for Monte Carlo simulations of radiotherapy beams

    NASA Astrophysics Data System (ADS)

    Popescu, I. A.; Shaw, C. P.; Zavgorodni, S. F.; Beckham, W. A.

    2005-07-01

    Monte Carlo (MC) simulations have traditionally been used for single field relative comparisons with experimental data or commercial treatment planning systems (TPS). However, clinical treatment plans commonly involve more than one field. Since the contribution of each field must be accurately quantified, multiple field MC simulations are only possible by employing absolute dosimetry. Therefore, we have developed a rigorous calibration method that allows the incorporation of monitor units (MU) in MC simulations. This absolute dosimetry formalism can be easily implemented by any BEAMnrc/DOSXYZnrc user, and applies to any configuration of open and blocked fields, including intensity-modulated radiation therapy (IMRT) plans. Our approach involves the relationship between the dose scored in the monitor ionization chamber of a radiotherapy linear accelerator (linac), the number of initial particles incident on the target, and the field size. We found that for a 10 × 10 cm2 field of a 6 MV photon beam, 1 MU corresponds, in our model, to 8.129 × 1013 ± 1.0% electrons incident on the target and a total dose of 20.87 cGy ± 1.0% in the monitor chambers of the virtual linac. We present an extensive experimental verification of our MC results for open and intensity-modulated fields, including a dynamic 7-field IMRT plan simulated on the CT data sets of a cylindrical phantom and of a Rando anthropomorphic phantom, which were validated by measurements using ionization chambers and thermoluminescent dosimeters (TLD). Our simulation results are in excellent agreement with experiment, with percentage differences of less than 2%, in general, demonstrating the accuracy of our Monte Carlo absolute dose calculations.

  11. Absolute dose calculations for Monte Carlo simulations of radiotherapy beams.

    PubMed

    Popescu, I A; Shaw, C P; Zavgorodni, S F; Beckham, W A

    2005-07-21

    Monte Carlo (MC) simulations have traditionally been used for single field relative comparisons with experimental data or commercial treatment planning systems (TPS). However, clinical treatment plans commonly involve more than one field. Since the contribution of each field must be accurately quantified, multiple field MC simulations are only possible by employing absolute dosimetry. Therefore, we have developed a rigorous calibration method that allows the incorporation of monitor units (MU) in MC simulations. This absolute dosimetry formalism can be easily implemented by any BEAMnrc/DOSXYZnrc user, and applies to any configuration of open and blocked fields, including intensity-modulated radiation therapy (IMRT) plans. Our approach involves the relationship between the dose scored in the monitor ionization chamber of a radiotherapy linear accelerator (linac), the number of initial particles incident on the target, and the field size. We found that for a 10 x 10 cm2 field of a 6 MV photon beam, 1 MU corresponds, in our model, to 8.129 x 10(13) +/- 1.0% electrons incident on the target and a total dose of 20.87 cGy +/- 1.0% in the monitor chambers of the virtual linac. We present an extensive experimental verification of our MC results for open and intensity-modulated fields, including a dynamic 7-field IMRT plan simulated on the CT data sets of a cylindrical phantom and of a Rando anthropomorphic phantom, which were validated by measurements using ionization chambers and thermoluminescent dosimeters (TLD). Our simulation results are in excellent agreement with experiment, with percentage differences of less than 2%, in general, demonstrating the accuracy of our Monte Carlo absolute dose calculations.

  12. Optoelectronic device for the measurement of the absolute linear position in the micrometric displacement range

    NASA Astrophysics Data System (ADS)

    Morlanes, Tomas; de la Pena, Jose L.; Sanchez-Brea, Luis M.; Alonso, Jose; Crespo, Daniel; Saez-Landete, Jose B.; Bernabeu, Eusebio

    2005-07-01

    In this work, an optoelectronic device that provides the absolute position of a measurement element with respect to a pattern scale upon switch-on is presented. That means that there is not a need to perform any kind of transversal displacement after the startup of the system. The optoelectronic device is based on the process of light propagation passing through a slit. A light source with a definite size guarantees the relation of distances between the different elements that constitute our system and allows getting a particular optical intensity profile that can be measured by an electronic post-processing device providing the absolute location of the system with a resolution of 1 micron. The accuracy of this measuring device is restricted to the same limitations of any incremental position optical encoder.

  13. Differential cross sections for electron impact excitation of the Herzberg pseudocontinuum of molecular oxygen

    NASA Astrophysics Data System (ADS)

    Green, M. A.; Maddern, T.; Brunger, M. J.; Campbell, L.; Cartwright, D. C.; Newell, W. R.; Teubner, P. J. O.

    2002-09-01

    We report differential cross sections (DCSs) for electron impact excitation of the sum (c1Σ u- + A'3 Δ u + A3 Σ u+) of the three states that constitute the Herzberg pseudocontinuum in O2. These DCSs were measured at seven incident electron energies in the range 9-20 eV and over the scattered electron angular range 10-90°. We note that this represents a far more detailed study than has hitherto previously been reported. In their review on electron-diatomic molecule scattering systems, Brunger and Buckman (Brunger M J and Buckman S J 2002 Phys. Rep. 357 215) clearly identified gaps in our knowledge for electron impact excitation of the Herzberg electronic states. The present study rectifies this situation and, additionally, seeks to stimulate theoreticians to extend their existing integral cross section calculations, for the c1 Σ u-, A'3 Δ u and A3 Σ u+ states, to the DCS-level.

  14. Absolute and angular efficiencies of a microchannel-plate position-sensitive detector

    NASA Technical Reports Server (NTRS)

    Gao, R. S.; Gibner, P. S.; Newman, J. H.; Smith, K. A.; Stebbings, R. F.

    1984-01-01

    This paper presents a characterization of a commercially available position-sensitive detector of energetic ions and neutrals. The detector consists of two microchannel plates followed by a resistive position-encoding anode. The work includes measurement of absolute efficiencies of H(+), He(+), and O(+) ions in the energy range between 250 and 5000 eV, measurement of relative detection efficiencies as a function of particle impact angle, and a simple method for accurate measurement of the time at which a particle strikes the detector.

  15. Non-equilibrium calculations of atmospheric processes initiated by electron impact.

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.

    2007-05-01

    Electron impact in the atmosphere produces ionisation, dissociation, electronic excitation and vibrational excitation of atoms and molecules. The products can then take part in chemical reactions, recombination with electrons, or radiative or collisional deactivation. While most such processes are fast, some longer--lived species do not reach equilibrium. The electron source (photoelectrons or auroral electrons) also varies over time and longer-lived species can move substantially in altitude by molecular, ambipolar or eddy diffusion. Hence non-equilibrium calculations are required in some circumstances. Such time-step calculations need to have sufficiently short steps so that the fastest processes are still calculated correctly, but this can lead to computation times that are too large. Hence techniques to allow for longer time steps by incorporating equilibrium calculations are described. Examples are given for results of atmospheric non-equilibrium calculations, including the populations of the vibrational levels of ground state N2, the electron density and its dependence on vibrationally excited N2, predictions of nitric oxide density, and detailed processes during short duration auroral events.

  16. Evaluating the Relative Environmental Impact of Countries

    PubMed Central

    Bradshaw, Corey J. A.; Giam, Xingli; Sodhi, Navjot S.

    2010-01-01

    Environmental protection is critical to maintain ecosystem services essential for human well-being. It is important to be able to rank countries by their environmental impact so that poor performers as well as policy ‘models’ can be identified. We provide novel metrics of country-specific environmental impact ranks – one proportional to total resource availability per country and an absolute (total) measure of impact – that explicitly avoid incorporating confounding human health or economic indicators. Our rankings are based on natural forest loss, habitat conversion, marine captures, fertilizer use, water pollution, carbon emissions and species threat, although many other variables were excluded due to a lack of country-specific data. Of 228 countries considered, 179 (proportional) and 171 (absolute) had sufficient data for correlations. The proportional index ranked Singapore, Korea, Qatar, Kuwait, Japan, Thailand, Bahrain, Malaysia, Philippines and Netherlands as having the highest proportional environmental impact, whereas Brazil, USA, China, Indonesia, Japan, Mexico, India, Russia, Australia and Peru had the highest absolute impact (i.e., total resource use, emissions and species threatened). Proportional and absolute environmental impact ranks were correlated, with mainly Asian countries having both high proportional and absolute impact. Despite weak concordance among the drivers of environmental impact, countries often perform poorly for different reasons. We found no evidence to support the environmental Kuznets curve hypothesis of a non-linear relationship between impact and per capita wealth, although there was a weak reduction in environmental impact as per capita wealth increases. Using structural equation models to account for cross-correlation, we found that increasing wealth was the most important driver of environmental impact. Our results show that the global community not only has to encourage better environmental performance in less

  17. Evaluating the relative environmental impact of countries.

    PubMed

    Bradshaw, Corey J A; Giam, Xingli; Sodhi, Navjot S

    2010-05-03

    Environmental protection is critical to maintain ecosystem services essential for human well-being. It is important to be able to rank countries by their environmental impact so that poor performers as well as policy 'models' can be identified. We provide novel metrics of country-specific environmental impact ranks - one proportional to total resource availability per country and an absolute (total) measure of impact - that explicitly avoid incorporating confounding human health or economic indicators. Our rankings are based on natural forest loss, habitat conversion, marine captures, fertilizer use, water pollution, carbon emissions and species threat, although many other variables were excluded due to a lack of country-specific data. Of 228 countries considered, 179 (proportional) and 171 (absolute) had sufficient data for correlations. The proportional index ranked Singapore, Korea, Qatar, Kuwait, Japan, Thailand, Bahrain, Malaysia, Philippines and Netherlands as having the highest proportional environmental impact, whereas Brazil, USA, China, Indonesia, Japan, Mexico, India, Russia, Australia and Peru had the highest absolute impact (i.e., total resource use, emissions and species threatened). Proportional and absolute environmental impact ranks were correlated, with mainly Asian countries having both high proportional and absolute impact. Despite weak concordance among the drivers of environmental impact, countries often perform poorly for different reasons. We found no evidence to support the environmental Kuznets curve hypothesis of a non-linear relationship between impact and per capita wealth, although there was a weak reduction in environmental impact as per capita wealth increases. Using structural equation models to account for cross-correlation, we found that increasing wealth was the most important driver of environmental impact. Our results show that the global community not only has to encourage better environmental performance in less

  18. Absolute calibration of a multichannel plate detector for low energy O, O-, and O+

    NASA Astrophysics Data System (ADS)

    Stephen, T. M.; Peko, B. L.

    2000-03-01

    Absolute detection efficiencies of a commercial multichannel plate detector have been measured for O, O+, and O-, impacting at normal incidence for energies ranging from 30-1000 eV. In addition, the detection efficiencies for O relative to its ions are presented, as they may have a more universal application. The absolute detection efficiencies are strongly energy dependent and significant differences are observed for the various charge states at lower energies. The detection efficiencies for the different charge states appear to converge at higher energies. The strongest energy dependence is for O+; the detection efficiency varies by three orders of magnitude across the energy range studied. The weakest dependence is for O-, which varies less than one order of magnitude.

  19. Determination of collagen fibril size via absolute measurements of second-harmonic generation signals

    NASA Astrophysics Data System (ADS)

    Bancelin, Stéphane; Aimé, Carole; Gusachenko, Ivan; Kowalczuk, Laura; Latour, Gaël; Coradin, Thibaud; Schanne-Klein, Marie-Claire

    2014-09-01

    The quantification of collagen fibril size is a major issue for the investigation of pathological disorders associated with structural defects of the extracellular matrix. Second-harmonic generation microscopy is a powerful technique to characterize the macromolecular organization of collagen in unstained biological tissues. Nevertheless, due to the complex coherent building of this nonlinear optical signal, it has never been used to measure fibril diameter so far. Here we report absolute measurements of second-harmonic signals from isolated fibrils down to 30 nm diameter, via implementation of correlative second-harmonic-electron microscopy. Moreover, using analytical and numerical calculations, we demonstrate that the high sensitivity of this technique originates from the parallel alignment of collagen triple helices within fibrils and the subsequent constructive interferences of second-harmonic radiations. Finally, we use these absolute measurements as a calibration for ex vivo quantification of fibril diameter in the Descemet’s membrane of a diabetic rat cornea.

  20. Triply differential measurements of single ionization of argon by 1-keV positron and electron impact

    NASA Astrophysics Data System (ADS)

    Gavin, J.; de Lucio, O. G.; DuBois, R. D.

    2017-06-01

    By establishing coincidences between target ions and scattered projectiles, and coincidences between target ions, scattered projectiles, and ejected electrons, triply differential cross-section (TDCS) information was generated in terms of projectile energy loss and scattering angles for interactions between 1-keV positrons and electrons and Ar atoms. The conversion of the raw experimental information to the TDCS is discussed. The single-ionization TDCS exhibits two distinguishable regions (lobes) where binary and recoil interactions can be described by two peaks. A comparison of the positron and electron impact data shows that the relative intensity of both binary and recoil interactions decreases exponentially as a function of the momentum transfer and is larger when ionization is induced by positron impact, when compared with electron impact.

  1. Investigating Absolute Value: A Real World Application

    ERIC Educational Resources Information Center

    Kidd, Margaret; Pagni, David

    2009-01-01

    Making connections between various representations is important in mathematics. In this article, the authors discuss the numeric, algebraic, and graphical representations of sums of absolute values of linear functions. The initial explanations are accessible to all students who have experience graphing and who understand that absolute value simply…

  2. Theoretical and experimental differential cross sections for electron impact excitation of the electronic bands of furfural

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Neves, R. F. C.; Lopes, M. C. A.; da Costa, R. F.; do N. Varella, M. T.; Bettega, M. H. F.; Lima, M. A. P.; García, G.; Limão-Vieira, P.; Brunger, M. J.

    2016-03-01

    We report results from a joint experimental and theoretical investigation into electron scattering from the important industrial species furfural (C5H4O2). Specifically, differential cross sections (DCSs) have been measured and calculated for the electron-impact excitation of the electronic states of C5H4O2. The measurements were carried out at energies in the range 20-40 eV, and for scattered-electron angles between 10° and 90°. The energy resolution of those experiments was typically ˜80 meV. Corresponding Schwinger multichannel method with pseudo-potential calculations, for energies between 6-50 eV and with and without Born-closure, were also performed for a sub-set of the excited electronic-states that were accessed in the measurements. Those calculations were undertaken at the static exchange plus polarisation-level using a minimum orbital basis for single configuration interaction (MOB-SCI) approach. Agreement between the measured and calculated DCSs was qualitatively quite good, although to obtain quantitative accord, the theory would need to incorporate even more channels into the MOB-SCI. The role of multichannel coupling on the computed electronic-state DCSs is also explored in some detail.

  3. Stimulus probability effects in absolute identification.

    PubMed

    Kent, Christopher; Lamberts, Koen

    2016-05-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of presentation probability on both proportion correct and response times. The effects were moderated by the ubiquitous stimulus position effect. The accuracy and response time data were predicted by an exemplar-based model of perceptual cognition (Kent & Lamberts, 2005). The bow in discriminability was also attenuated when presentation probability for middle items was relatively high, an effect that will constrain future model development. The study provides evidence for item-specific learning in absolute identification. Implications for other theories of absolute identification are discussed. (PsycINFO Database Record (c) 2016 APA, all rights reserved).

  4. Electron impact excitation of SO2 - Differential, integral, and momentum transfer cross sections

    NASA Technical Reports Server (NTRS)

    Vuskovic, L.; Trajmar, S.

    1982-01-01

    Electron impact excitation of the electronic states of SO2 was investigated. Differential, integral, and inelastic momentum transfer cross sections were obtained by normalizing the relative measurements to the elastic cross sections. The cross sections are given for seven spectral ranges of the energy-loss spectra extending from the lowest electronic state to near the first ionization limit. Most of the regions represent the overlap of several electronic transitions. No measurements for these cross sections have been reported previously.

  5. Absolute measurement of undulator radiation in the extreme ultraviolet

    NASA Astrophysics Data System (ADS)

    Maezawa, H.; Mitani, S.; Suzuki, Y.; Kanamori, H.; Tamamushi, S.; Mikuni, A.; Kitamura, H.; Sasaki, T.

    1983-04-01

    The spectral brightness of undulator radiation emitted by the model PMU-1 incorporated in the SOR-RING, the dedicated synchrotron radiation source in Tokyo, has been studied in the extreme ultraviolet region from 21.6 to 72.9 eV as a function of the electron energy γ, the field parameter K, and the angle of observation ϴ in the absolute scale. A series of measurements covering the first and the second harmonic component of undulator radiation was compared with the fundamental formula λ n= {λ 0}/{2nγ 2}( {1+K 2}/{2}+γϴ 2 and the effects of finite emittance were studied. The brightness at the first peak was smaller than the theoretical value, while an enhanced second harmonic component was observed.

  6. Absolute Determination of High DC Voltages by Means of Frequency Measurement

    NASA Astrophysics Data System (ADS)

    Peier, Dirk; Schulz, Bernd

    1983-01-01

    A novel absolute measuring procedure is presented for the definition of fixed points of the voltage in the 100 kV range. The method is based on transit time measurements with accelerated electrons. By utilizing the selective interaction of a monoenergetic electron beam with the electromagnetic field of a special cavity resonator, the voltage is referred to fundamental constants and the base unit second. Possible balance voltages are indicated by a current detector. Experimental investigations are carried out with resonators in the normal conducting range. With a copper resonator operating at the temperature of boiling nitrogen (77 K), the relative uncertainty of the voltage points is estimated to be +/- 4 × 10-4. The technically realizable uncertainty can be reduced to +/- 1 × 10-5 by the proposed application of a superconducting niobium resonator. Thus this measuring device becomes suitable as a primary standard for the high-voltage range.

  7. Absolute neutrino mass measurements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wolf, Joachim

    2011-10-06

    The neutrino mass plays an important role in particle physics, astrophysics and cosmology. In recent years the detection of neutrino flavour oscillations proved that neutrinos carry mass. However, oscillation experiments are only sensitive to the mass-squared difference of the mass eigenvalues. In contrast to cosmological observations and neutrino-less double beta decay (0v2{beta}) searches, single {beta}-decay experiments provide a direct, model-independent way to determine the absolute neutrino mass by measuring the energy spectrum of decay electrons at the endpoint region with high accuracy.Currently the best kinematic upper limits on the neutrino mass of 2.2eV have been set by two experiments inmore » Mainz and Troitsk, using tritium as beta emitter. The next generation tritium {beta}-experiment KATRIN is currently under construction in Karlsruhe/Germany by an international collaboration. KATRIN intends to improve the sensitivity by one order of magnitude to 0.2eV. The investigation of a second isotope ({sup 137}Rh) is being pursued by the international MARE collaboration using micro-calorimeters to measure the beta spectrum. The technology needed to reach 0.2eV sensitivity is still in the R and D phase. This paper reviews the present status of neutrino-mass measurements with cosmological data, 0v2{beta} decay and single {beta}-decay.« less

  8. A Conceptual Approach to Absolute Value Equations and Inequalities

    ERIC Educational Resources Information Center

    Ellis, Mark W.; Bryson, Janet L.

    2011-01-01

    The absolute value learning objective in high school mathematics requires students to solve far more complex absolute value equations and inequalities. When absolute value problems become more complex, students often do not have sufficient conceptual understanding to make any sense of what is happening mathematically. The authors suggest that the…

  9. Electronic Position Sensor for Power Operated Accessory

    DOEpatents

    Haag, Ronald H.; Chia, Michael I.

    2005-05-31

    An electronic position sensor for use with a power operated vehicle accessory, such as a power liftgate. The position sensor includes an elongated resistive circuit that is mounted such that it is stationary and extends along the path of a track portion of the power operated accessory. The position sensor further includes a contact nub mounted to a link member that moves within the track portion such that the contact nub is slidingly biased against the elongated circuit. As the link member moves under the force of a motor-driven output gear, the contact nub slides along the surface of the resistive circuit, thereby affecting the overall resistance of the circuit. The position sensor uses the overall resistance to provide an electronic position signal to an ECU, wherein the signal is indicative of the absolute position of the power operated accessory. Accordingly, the electronic position sensor is capable of providing an electronic signal that enables the ECU to track the absolute position of the power operated accessory.

  10. Electron beam collimation with a photon MLC for standard electron treatments

    NASA Astrophysics Data System (ADS)

    Mueller, S.; Fix, M. K.; Henzen, D.; Frei, D.; Frauchiger, D.; Loessl, K.; Stampanoni, M. F. M.; Manser, P.

    2018-01-01

    Standard electron treatments are currently still performed using standard or molded patient-specific cut-outs placed in the electron applicator. Replacing cut-outs and electron applicators with a photon multileaf collimator (pMLC) for electron beam collimation would make standard electron treatments more efficient and would facilitate advanced treatment techniques like modulated electron radiotherapy (MERT) and mixed beam radiotherapy (MBRT). In this work, a multiple source Monte Carlo beam model for pMLC shaped electron beams commissioned at a source-to-surface distance (SSD) of 70 cm is extended for SSDs of up to 100 cm and validated for several Varian treatment units with field sizes typically used for standard electron treatments. Measurements and dose calculations agree generally within 3% of the maximal dose or 2 mm distance to agreement. To evaluate the dosimetric consequences of using pMLC collimated electron beams for standard electron treatments, pMLC-based and cut-out-based treatment plans are created for a left and a right breast boost, a sternum, a testis and a parotid gland case. The treatment plans consist of a single electron field, either alone (1E) or in combination with two 3D conformal tangential photon fields (1E2X). For each case, a pMLC plan with similar treatment plan quality in terms of dose homogeneity to the target and absolute mean dose values to the organs at risk (OARs) compared to a cut-out plan is found. The absolute mean dose to an OAR is slightly increased for pMLC-based compared to cut-out-based 1E plans if the OAR is located laterally close to the target with respect to beam direction, or if a 6 MeV electron beam is used at an extended SSD. In conclusion, treatment plans using cut-out collimation can be replaced by plans of similar treatment plan quality using pMLC collimation with accurately calculated dose distributions.

  11. Absolute pitch in a four-year-old boy with autism.

    PubMed

    Brenton, James N; Devries, Seth P; Barton, Christine; Minnich, Heike; Sokol, Deborah K

    2008-08-01

    Absolute pitch is the ability to identify the pitch of an isolated tone. We report on a 4-year-old boy with autism and absolute pitch, one of the youngest reported in the literature. Absolute pitch is thought to be attributable to a single gene, transmitted in an autosomal-dominant fashion. The association of absolute pitch with autism raises the speculation that this talent could be linked to a genetically distinct subset of children with autism. Further, the identification of absolute pitch in even young children with autism may lead to a lifelong skill.

  12. The Absolute Spectrum Polarimeter (ASP)

    NASA Technical Reports Server (NTRS)

    Kogut, A. J.

    2010-01-01

    The Absolute Spectrum Polarimeter (ASP) is an Explorer-class mission to map the absolute intensity and linear polarization of the cosmic microwave background and diffuse astrophysical foregrounds over the full sky from 30 GHz to 5 THz. The principal science goal is the detection and characterization of linear polarization from an inflationary epoch in the early universe, with tensor-to-scalar ratio r much greater than 1O(raised to the power of { -3}) and Compton distortion y < 10 (raised to the power of{-6}). We describe the ASP instrument and mission architecture needed to detect the signature of an inflationary epoch in the early universe using only 4 semiconductor bolometers.

  13. The absolute disparity anomaly and the mechanism of relative disparities.

    PubMed

    Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

    2016-06-01

    There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1).

  14. The absolute disparity anomaly and the mechanism of relative disparities

    PubMed Central

    Chopin, Adrien; Levi, Dennis; Knill, David; Bavelier, Daphne

    2016-01-01

    There has been a long-standing debate about the mechanisms underlying the perception of stereoscopic depth and the computation of the relative disparities that it relies on. Relative disparities between visual objects could be computed in two ways: (a) using the difference in the object's absolute disparities (Hypothesis 1) or (b) using relative disparities based on the differences in the monocular separations between objects (Hypothesis 2). To differentiate between these hypotheses, we measured stereoscopic discrimination thresholds for lines with different absolute and relative disparities. Participants were asked to judge the depth of two lines presented at the same distance from the fixation plane (absolute disparity) or the depth between two lines presented at different distances (relative disparity). We used a single stimulus method involving a unique memory component for both conditions, and no extraneous references were available. We also measured vergence noise using Nonius lines. Stereo thresholds were substantially worse for absolute disparities than for relative disparities, and the difference could not be explained by vergence noise. We attribute this difference to an absence of conscious readout of absolute disparities, termed the absolute disparity anomaly. We further show that the pattern of correlations between vergence noise and absolute and relative disparity acuities can be explained jointly by the existence of the absolute disparity anomaly and by the assumption that relative disparity information is computed from absolute disparities (Hypothesis 1). PMID:27248566

  15. Effective collision strengths for the electron impact excitation of Mg

    NASA Astrophysics Data System (ADS)

    Hudson, C. E.; Ramsbottom, C. A.; Norrington, P. H.; Scott, M. P.

    2008-05-01

    Electron impact excitation collision strengths for fine structure transitions of Mg,have been determined by a Breit-Pauli R-matrix calculation. The target states are represented by configuration interaction wavefunctions and consist of the 19 lowest LS states, having configurations 2s^22p^4, 2s2p^5, 2p^6, 2s^22p^33s and 2s^22p^33p. These target states give rise to 37 fine structure levels and 666 possible transitions. The effective collision strengths are calculated by averaging the electron collision strengths over a Maxwellian distribution of electron velocities. Effective collision strengths for transitions between the fine structure levels are given for electron temperatures in the range 10Te(K) = 3.0 - 7.0. Results are compared with the previous R-matrix calculation of Butler & Zeippen (AASS, 1994) and the recent Distorted Wave evaluations of Bhatia, Landi & Eissner (ADNDT, 2006).

  16. Differential Cross Sections for Ionization of Argon by 1 keV Positron and Electron Impact

    NASA Astrophysics Data System (ADS)

    Gavin, J.; DuBois, R. D.; de Lucio, O. G.

    2014-04-01

    Differential information was generated by establishing coincidences and imposing conditions on data recorded for target ions, scattered projectiles, and ejected electrons, as a function of projectile energy loss and scattering angles; in order to describe the interaction between a positron (electron) 1 keV beam and a simple Ar jet. Single ionization triply differential cross section (TDCS) results exhibit two distinct regions (lobes) for which binary (events arising from 2-body interaction) and recoil (events which can only be produced by many-body interactions) interactions are associated. Results indicate that binary events are significantly larger for positron impact, in accordance with theoretical predictions. A similar feature is found for different energy losses and scattering angles. Intensity of the recoil lobe for both projectiles, positron and electron, is observed to depend on the energy loss and scattering angle. Also, it can be noticed that for positron impact the recoil interactions intensity is larger than that observed for electron impact.

  17. Introducing the Mean Absolute Deviation "Effect" Size

    ERIC Educational Resources Information Center

    Gorard, Stephen

    2015-01-01

    This paper revisits the use of effect sizes in the analysis of experimental and similar results, and reminds readers of the relative advantages of the mean absolute deviation as a measure of variation, as opposed to the more complex standard deviation. The mean absolute deviation is easier to use and understand, and more tolerant of extreme…

  18. Monolithically integrated absolute frequency comb laser system

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Wanke, Michael C.

    2016-07-12

    Rather than down-convert optical frequencies, a QCL laser system directly generates a THz frequency comb in a compact monolithically integrated chip that can be locked to an absolute frequency without the need of a frequency-comb synthesizer. The monolithic, absolute frequency comb can provide a THz frequency reference and tool for high-resolution broad band spectroscopy.

  19. Electron Emission from Amorphous Solid Water Induced by Passage of Energetic Protons and Fluorine Ions

    PubMed Central

    Toburen, L. H.; McLawhorn, S. L.; McLawhorn, R. A.; Carnes, K. D.; Dingfelder, M.; Shinpaugh, J. L.

    2013-01-01

    Absolute doubly differential electron emission yields were measured from thin films of amorphous solid water (ASW) after the transmission of 6 MeV protons and 19 MeV (1 MeV/nucleon) fluorine ions. The ASW films were frozen on thin (1-μm) copper foils cooled to approximately 50 K. Electrons emitted from the films were detected as a function of angle in both the forward and backward direction and as a function of the film thickness. Electron energies were determined by measuring the ejected electron time of flight, a technique that optimizes the accuracy of measuring low-energy electron yields, where the effects of molecular environment on electron transport are expected to be most evident. Relative electron emission yields were normalized to an absolute scale by comparison of the integrated total yields for proton-induced electron emission from the copper substrate to values published previously. The absolute doubly differential yields from ASW are presented along with integrated values, providing single differential and total electron emission yields. These data may provide benchmark tests of Monte Carlo track structure codes commonly used for assessing the effects of radiation quality on biological effectiveness. PMID:20681805

  20. Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

    NASA Astrophysics Data System (ADS)

    Ranković, Miloš Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-02-01

    We have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS2) and allows performing action spectroscopy. Electron impact MS2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1 s excitation. Both MS2 and single ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.

  1. Integral elastic, electronic-state, ionization, and total cross sections for electron scattering with furfural

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Jones, D. B.; Costa, R. F. da; Departamento de Física, Universidade Federal do Espírito Santo, 29075-910, Vitória, Espírito Santo

    We report absolute experimental integral cross sections (ICSs) for electron impact excitation of bands of electronic-states in furfural, for incident electron energies in the range 20–250 eV. Wherever possible, those results are compared to corresponding excitation cross sections in the structurally similar species furan, as previously reported by da Costa et al. [Phys. Rev. A 85, 062706 (2012)] and Regeta and Allan [Phys. Rev. A 91, 012707 (2015)]. Generally, very good agreement is found. In addition, ICSs calculated with our independent atom model (IAM) with screening corrected additivity rule (SCAR) formalism, extended to account for interference (I) terms that arisemore » due to the multi-centre nature of the scattering problem, are also reported. The sum of those ICSs gives the IAM-SCAR+I total cross section for electron–furfural scattering. Where possible, those calculated IAM-SCAR+I ICS results are compared against corresponding results from the present measurements with an acceptable level of accord being obtained. Similarly, but only for the band I and band II excited electronic states, we also present results from our Schwinger multichannel method with pseudopotentials calculations. Those results are found to be in good qualitative accord with the present experimental ICSs. Finally, with a view to assembling a complete cross section data base for furfural, some binary-encounter-Bethe-level total ionization cross sections for this collision system are presented.« less

  2. Propensity for distinguishing two free electrons with equal energies in electron-impact ionization of helium

    NASA Astrophysics Data System (ADS)

    Ren, Xueguang; Senftleben, Arne; Pflüger, Thomas; Bartschat, Klaus; Zatsarinny, Oleg; Berakdar, Jamal; Colgan, James; Pindzola, Michael S.; Bray, Igor; Fursa, Dmitry V.; Dorn, Alexander

    2015-11-01

    We report a combined experimental and theoretical study on the electron-impact ionization of helium at E0=70.6 eV and equal energy sharing of the two outgoing electrons (E1=E2=23 eV ), where a double-peak or dip structure in the binary region of the triple differential cross section is observed. The experimental cross sections are compared with results from convergent close-coupling (CCC), B -spline R-matrix-with-pseudostates (BSR), and time-dependent close-coupling (TDCC) calculations, as well as predictions from the dynamic screening three-Coulomb (DS3C) theory. Excellent agreement is obtained between experiment and the nonperturbative CCC, BSR, and TDCC theories, and good agreement is also found for the DS3C model. The data are further analyzed regarding contributions in particular coupling schemes for the spins of either the two outgoing electrons or one of the outgoing electrons and the 1 s electron remaining in the residual ion. While both coupling schemes can be used to explain the observed double-peak structure in the cross section, the second one allows for the isolation of the exchange contribution between the incident projectile and the target. For different observation angles of the two outgoing electrons, we interpret the results as a propensity for distinguishing these two electrons—one being more likely the incident projectile and the other one being more likely ejected from the target.

  3. Application of relativistic coupled-cluster theory to electron impact excitation of Mg+ in the plasma environment

    NASA Astrophysics Data System (ADS)

    Sharma, Lalita; Sahoo, Bijaya Kumar; Malkar, Pooja; Srivastava, Rajesh

    2018-01-01

    A relativistic coupled-cluster theory is implemented to study electron impact excitations of atomic species. As a test case, the electron impact excitations of the 3 s 2 S 1/2-3 p 2 P 1/2;3/2 resonance transitions are investigated in the singly charged magnesium (Mg+) ion using this theory. Accuracies of wave functions of Mg+ are justified by evaluating its attachment energies of the relevant states and compared with the experimental values. The continuum wave function of the projectile electron are obtained by solving Dirac equations assuming distortion potential as static potential of the ground state of Mg+. Comparison of the calculated electron impact excitation differential and total cross-sections with the available measurements are found to be in very good agreements at various incident electron energies. Further, calculations are carried out in the plasma environment in the Debye-Hückel model framework, which could be useful in the astrophysics. Influence of plasma strength on the cross-sections as well as linear polarization of the photon emission in the 3 p 2 P 3/2-3 s 2 S 1/2 transition is investigated for different incident electron energies.

  4. Dissociative Ionization of Benzene by Electron Impact

    NASA Technical Reports Server (NTRS)

    Huo, Winifred; Dateo, Christopher; Kwak, Dochan (Technical Monitor)

    2002-01-01

    We report a theoretical study of the dissociative ionization (DI) of benzene from the low-lying ionization channels. Our approach makes use of the fact that electron motion is much faster than nuclear motion and DI is treated as a two-step process. The first step is electron-impact ionization resulting in an ion with the same nuclear geometry as the neutral molecule. In the second step the nuclei relax from the initial geometry and undergo unimolecular dissociation. For the ionization process we use the improved binary-encounter dipole (iBED) model. For the unimolecular dissociation step, we study the steepest descent reaction path to the minimum of the ion potential energy surface. The path is used to analyze the probability of unimolecular dissociation and to determine the product distributions. Our analysis of the dissociation products and the thresholds of the productions are compared with the result dissociative photoionization measurements of Feng et al. The partial oscillator strengths from Feng et al. are then used in the iBED cross section calculations.

  5. Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

    DOE PAGES

    Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

    2016-02-11

    In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

  6. Electron impact action spectroscopy of mass/charge selected macromolecular ions: Inner-shell excitation of ubiquitin protein

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rankovic, Milos Lj.; Giuliani, Alexandre; Milosavljevic, Aleksandar R.

    In this study, we have performed inner-shell electron impact action spectroscopy of mass and charge selected macromolecular ions. For this purpose, we have coupled a focusing electron gun with a linear quadrupole ion trap mass spectrometer. This experiment represents a proof of principle that an energy-tunable electron beam can be used in combination with radio frequency traps as an activation method in tandem mass spectrometry (MS 2) and allows performing action spectroscopy. Electron impact MS 2 spectra of multiply protonated ubiquitin protein ion have been recorded at incident electron energies around the carbon 1s excitation. Both MS 2 and singlemore » ionization energy dependence spectra are compared with literature data obtained using the soft X-ray activation conditions.« less

  7. Triple differential cross sections for the electron-impact ionization of H{sub 2} molecules for equal and unequal outgoing electron energies

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Colgan, J.; Al-Hagan, O.; Madison, D. H.

    A comprehensive theoretical and experimental investigation of the triple differential cross sections arising from the electron-impact ionization of molecular hydrogen is made, at an incident electron energy of 35.4 eV, for cases where the outgoing electrons have equal and unequal energies, and for a range of experimental geometries. Generally, good agreement is found between two theoretical approaches and experiment, with the best agreement arising for intermediate geometries with large gun angles and for the perpendicular geometry.

  8. Enantiomeric Lignans and Neolignans from Phyllanthus glaucus: Enantioseparation and Their Absolute Configurations

    NASA Astrophysics Data System (ADS)

    Wu, Zhaodi; Lai, Yongji; Zhou, Lei; Wu, Ye; Zhu, Hucheng; Hu, Zhengxi; Yang, Jing; Zhang, Jinwen; Wang, Jianping; Luo, Zengwei; Xue, Yongbo; Zhang, Yonghui

    2016-04-01

    Eight pairs of enantiomeric neolignans, norlignans, and sesquineolignans (1a/1b-8a/8b), together with five known neolignans (9a/9b and 10-12), have been isolated from 70% acetone extract of the whole plants of Phyllanthus glaucus Wall. (Euphorbiaceae). The racemic or partial racemic mixtures were successfully separated by chiral HPLC using different types of chiral columns with various mobile phases. Their structures were elucidated on the basis of extensive spectroscopic data. The absolute configurations of 2a/2b were determined by computational analysis of their electronic circular dichroism (ECD) spectrum, and the absolute configurations of other isolates were ascertained by comparing their experimental ECD spectra and optical rotation values with those of structure-relevant compounds reported in literatures. Compounds 4a/4b featured unique sesquineolignan skeletons with a novel 7-4‧-epoxy-8‧-8‧‧/7‧-2‧‧ scaffold, consisting of an aryltetrahydronaphthalene and a dihydrobenzofuran moiety. The planar structures of compounds 2, 3, 7, and 8 were documented previously; however, their absolute configurations were established for the first time in this study. The antioxidant activities of 1a/1b-8a/8b were evaluated using DPPH free radical scavenging assay, and the results demonstrated that compounds 1b and 3b showed potent DPPH radical scavenging activities with IC50 values of 5.987 ± 1.212 and 9.641 ± 0.865 μg/mL, respectively.

  9. Vortices for K-shell ionization of carbon by electron impact

    NASA Astrophysics Data System (ADS)

    Ward, S. J.; Macek, J. H.

    2014-05-01

    Using the Coulomb-Born approximation, we obtained a deep minimum in the TDCS for K-shell ionization of carbon by electron impact. The minimum is due to a vortex in the velocity field. We considered the electron to be ejected in the scattering plane, which we took to be the xz -plane. The minimum was obtained for the kinematics of an incident energy Ei = 1801 . 2 eV , scattering angle θf =4° , energy of ejected electron Ek = 5 . 5 eV , and angle of the ejected electron θk =239° . We analyzed the importance of various multipole components in an expansion of the Coulomb-Born T-matrix. We also considered the electron ejected out of the scattering plane for Ei = 1801 . 2 eV and θf =4° and located the positions of vortices for small but nonzero values of ky, the y - component of the momentum of the ejected electron. We constructed the vortex line for the kinematics of Ei = 1801 . 2 eV and θf =4° . S. J. W. and J. H. M. acknowledge support from NSF under grant no. PHYS- 0968638 and from D.O.E. under grant number DE-FG02-02ER15283, respectively.

  10. Interatomic relaxation processes induced in neon dimers by electron-impact ionization

    NASA Astrophysics Data System (ADS)

    Yan, S.; Zhang, P.; Stumpf, V.; Gokhberg, K.; Zhang, X. C.; Xu, S.; Li, B.; Shen, L. L.; Zhu, X. L.; Feng, W. T.; Zhang, S. F.; Zhao, D. M.; Ma, X.

    2018-01-01

    We report an experimental observation of the interatomic Coulombic decay (ICD) and radiative charge-transfer (RCT) processes in a Ne dimer (e ,2 e ) following a 380-eV electron impact. By detecting the N e+-N e+ cation pair and one of the emitted electrons in coincidence, the fingerprint of the ICD process initiated by the inner-valence ionization of Ne is obtained. Furthermore, the experimental results and ab initio calculations together unambiguously confirm the occurrence of the RCT process, and we show that most of the low-energy electrons produced in ionization of the Ne dimers are due to the ICD, which strongly suggests the importance of the ICD in causing radiation damage in a biological medium.

  11. Elastic scattering and vibrational excitation for electron impact on para-benzoquinone

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Blanco, F.; García, G.; da Costa, R. F.; Kossoski, F.; Varella, M. T. do N.; Bettega, M. H. F.; Lima, M. A. P.; White, R. D.; Brunger, M. J.

    2017-12-01

    We report on theoretical elastic and experimental vibrational-excitation differential cross sections (DCSs) for electron scattering from para-benzoquinone (C6H4O2), in the intermediate energy range 15-50 eV. The calculations were conducted with two different theoretical methodologies, the Schwinger multichannel method with pseudopotentials (SMCPP) and the independent atom method with screening corrected additivity rule (IAM-SCAR) that also now incorporates a further interference (I) term. The SMCPP with N energetically open electronic states (Nopen) at the static-exchange-plus-polarisation (Nopench-SEP) level was used to calculate the scattering amplitudes using a channel coupling scheme that ranges from 1ch-SE up to the 89ch-SEP level of approximation. We found that in going from the 38ch-SEP to the 89ch-SEP, at all energies considered here, the elastic DCSs did not change significantly in terms of both their shapes and magnitudes. This is a good indication that our SMCPP 89ch-SEP elastic DCSs are converged with respect to the multichannel coupling effect for the investigated intermediate energies. While agreement between our IAM-SCAR+I and SMCPP 89ch-SEP computations improves as the incident electron energy increases from 15 eV, overall the level of accord is only marginal. This is particularly true at middle scattering angles, suggesting that our SCAR and interference corrections are failing somewhat for this molecule below 50 eV. We also report experimental DCS results, using a crossed-beam apparatus, for excitation of some of the unresolved ("hybrid") vibrational quanta (bands I-III) of para-benzoquinone. Those data were derived from electron energy loss spectra that were measured over a scattered electron angular range of 10°-90° and put on an absolute scale using our elastic SMCPP 89ch-SEP DCS results. The energy resolution of our measurements was ˜80 meV, which is why, at least in part, the observed vibrational features were only partially resolved. To

  12. Modeling of anomalous electron mobility in Hall thrusters

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Koo, Justin W.; Boyd, Iain D.

    Accurate modeling of the anomalous electron mobility is absolutely critical for successful simulation of Hall thrusters. In this work, existing computational models for the anomalous electron mobility are used to simulate the UM/AFRL P5 Hall thruster (a 5 kW laboratory model) in a two-dimensional axisymmetric hybrid particle-in-cell Monte Carlo collision code. Comparison to experimental results indicates that, while these computational models can be tuned to reproduce the correct thrust or discharge current, it is very difficult to match all integrated performance parameters (thrust, power, discharge current, etc.) simultaneously. Furthermore, multiple configurations of these computational models can produce reasonable integrated performancemore » parameters. A semiempirical electron mobility profile is constructed from a combination of internal experimental data and modeling assumptions. This semiempirical electron mobility profile is used in the code and results in more accurate simulation of both the integrated performance parameters and the mean potential profile of the thruster. Results indicate that the anomalous electron mobility, while absolutely necessary in the near-field region, provides a substantially smaller contribution to the total electron mobility in the high Hall current region near the thruster exit plane.« less

  13. Electron-impact excitation heating rates in the atmosphere of Titan

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Kato, H.; Brunger, M. J.; Bradshaw, M. D.

    2010-09-01

    A previous study of various heating rates in the atmosphere of Titan included electron-impact excitation of molecular nitrogen as one component. This work examines this component in more detail, using a statistical equilibrium calculation to avoid approximations made in the earlier work. The sensitivity of the results to different cross-section sets is investigated. It is found that using recent and more physical cross sections for vibrational excitation produces a significant increase in the heating rate. On the other hand, using more accurate cross sections for the electronic states had little apparent effect on the heating rates when used within the approximations made in the previous model. However, the inclusion of more transitions in this study produces a significant increase in the electronic state heating rates, as states that were originally neglected are now accounted for here.

  14. Using, Seeing, Feeling, and Doing Absolute Value for Deeper Understanding

    ERIC Educational Resources Information Center

    Ponce, Gregorio A.

    2008-01-01

    Using sticky notes and number lines, a hands-on activity is shared that anchors initial student thinking about absolute value. The initial point of reference should help students successfully evaluate numeric problems involving absolute value. They should also be able to solve absolute value equations and inequalities that are typically found in…

  15. Absolute nuclear material assay using count distribution (LAMBDA) space

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Prasad, Mano K.; Snyderman, Neal J.; Rowland, Mark S.

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  16. Planck absolute entropy of a rotating BTZ black hole

    NASA Astrophysics Data System (ADS)

    Riaz, S. M. Jawwad

    2018-04-01

    In this paper, the Planck absolute entropy and the Bekenstein-Smarr formula of the rotating Banados-Teitelboim-Zanelli (BTZ) black hole are presented via a complex thermodynamical system contributed by its inner and outer horizons. The redefined entropy approaches zero as the temperature of the rotating BTZ black hole tends to absolute zero, satisfying the Nernst formulation of a black hole. Hence, it can be regarded as the Planck absolute entropy of the rotating BTZ black hole.

  17. Absolute nuclear material assay using count distribution (LAMBDA) space

    DOEpatents

    Prasad, Manoj K [Pleasanton, CA; Snyderman, Neal J [Berkeley, CA; Rowland, Mark S [Alamo, CA

    2012-06-05

    A method of absolute nuclear material assay of an unknown source comprising counting neutrons from the unknown source and providing an absolute nuclear material assay utilizing a model to optimally compare to the measured count distributions. In one embodiment, the step of providing an absolute nuclear material assay comprises utilizing a random sampling of analytically computed fission chain distributions to generate a continuous time-evolving sequence of event-counts by spreading the fission chain distribution in time.

  18. Lead-Free Electronics: Impact for Space Electronics

    NASA Technical Reports Server (NTRS)

    Sampson, Michael J.

    2010-01-01

    Pb is used as a constituent in solder alloys used to connect and attach electronic parts to printed wiring boards (PWBs). Similar Pbbearing alloys are electroplated or hot dipped onto the terminations of electronic parts to protect the terminations and make them solderable. Changing to Pb-free solders and termination finishes has introduced significant technical challenges into the supply chain. Tin/lead (Sn/Pb) alloys have been the solders of choice for electronics for more than 50 years. Pb-free solder alloys are available but there is not a plug-in replacement for 60/40 or 63/37 (Sn/Pb) alloys, which have been the industry workhorses.

  19. Absolute detection efficiency of a microchannel plate detector to X rays in the 1-100 KeV energy range

    NASA Astrophysics Data System (ADS)

    Burginyon, Gary A.; Jacoby, Barry A.; Wobser, James K.; Ernst, Richard; Ancheta, Dione S.; Tirsell, Kenneth G.

    1993-02-01

    There is little information in the literature on the performance of working micro-channel plate (MCP) detectors at high x-ray energies. We have measured the absolute efficiency of a microchannel-plate-intensified, subnanosecond, one dimensional imaging x-ray detector developed at LLNL in the 1 to 100 keV range and at 1.25 MeV. The detector consists of a gold photocathode deposited on the front surface of the MCP (optimized for Ni K(subscript (alpha) ) x rays) to convert x rays to electrons, an MCP to amplify the electrons, and a fast In:CdS phosphor that converts the electron's kinetic energy to light. The phosphor is coated on a fiber-optic faceplate to transmit the light out of the vacuum system. Electrostatic focusing electrodes compress the electron current out of the MCP in one dimension while preserving spatial resolution in the other. The calibration geometry, dictated by a recent experiment, required grazing incidence x rays (15.6 degree(s)) onto the MCP detector in order to maximize deliverable current. The experiment also used a second detector made up of 0.071 in. thick BC422 plastic scintillator material from the Bicron Corporation. We compare the absolute efficiencies of these two detectors in units of optical W/cm(superscript 2) into 4 (pi) per x ray W/cm(superscript 2) incident. At 7.47 keV and 900 volts MCP bias, the MCP detector delivers approximately 1400 times more light than the scintillator detector.

  20. On the importance of electron impact processes in excimer-pumped alkali laser-induced plasmas

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Markosyan, Aram H.

    We present that the excimer-pumped alkali laser (XPAL) system has recently been demonstrated in several different mixtures of alkali vapor and rare gas. Without special preventive measures, plasma formation during operation of XPAL is unavoidable. Some recent advancements in the availability of reliable data for electron impact collisions with atoms and molecules have enabled development of a complete reaction mechanism to investigate XPAL-induced plasmas. Here, we report on pathways leading to plasma formation in an Ar/C 2H 6/CsAr/C2H6/Cs XPAL sustained at different cell temperatures. We find that depending on the operating conditions, the contribution of electron impact processes can bemore » as little as bringing the excitation of Cs(P 2) states to higher level Cs** states, and can be as high as bringing Cs(P 2) excited states to a full ionization. Increasing the input pumping power or cell temperature, or decreasing the C 2H 6 mole fraction leads to electron impact processes dominating in plasma formation over the energy pooling mechanisms previously reported in literature.« less

  1. On the importance of electron impact processes in excimer-pumped alkali laser-induced plasmas

    DOE PAGES

    Markosyan, Aram H.

    2017-10-18

    We present that the excimer-pumped alkali laser (XPAL) system has recently been demonstrated in several different mixtures of alkali vapor and rare gas. Without special preventive measures, plasma formation during operation of XPAL is unavoidable. Some recent advancements in the availability of reliable data for electron impact collisions with atoms and molecules have enabled development of a complete reaction mechanism to investigate XPAL-induced plasmas. Here, we report on pathways leading to plasma formation in an Ar/C 2H 6/CsAr/C2H6/Cs XPAL sustained at different cell temperatures. We find that depending on the operating conditions, the contribution of electron impact processes can bemore » as little as bringing the excitation of Cs(P 2) states to higher level Cs** states, and can be as high as bringing Cs(P 2) excited states to a full ionization. Increasing the input pumping power or cell temperature, or decreasing the C 2H 6 mole fraction leads to electron impact processes dominating in plasma formation over the energy pooling mechanisms previously reported in literature.« less

  2. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Lucero, J. F., E-mail: fernando.lucero@hoperadiotherapy.com.gt; Hope International, Guatemala; Rojas, J. I., E-mail: isaac.rojas@siglo21.cr

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient’s entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  3. Electron-impact vibrational relaxation in high-temperature nitrogen

    NASA Technical Reports Server (NTRS)

    Lee, Jong-Hun

    1992-01-01

    Vibrational relaxation process of N2 molecules by electron-impact is examined for the future planetary entry environments. Multiple-quantum transitions from excited states to higher/lower states are considered for the electronic ground state of the nitrogen molecule N2 (X 1Sigma-g(+)). Vibrational excitation and deexcitation rate coefficients obtained by computational quantum chemistry are incorporated into the 'diffusion model' to evaluate the time variations of vibrational number densities of each energy state and total vibrational energy. Results show a non-Boltzmann distribution of number densities at the earlier stage of relaxation, which in turn suppresses the equilibrium process but affects little the time variation of total vibrational energy. An approximate rate equation and a corresponding relaxation time from the excited states, compatible with the system of flow conservation equations, are derived. The relaxation time from the excited states indicates the weak dependency of the initial vibrational temperature. The empirical curve-fit formula for the improved e-V relaxation time is obtained.

  4. Communication: Electron ionization of DNA bases.

    PubMed

    Rahman, M A; Krishnakumar, E

    2016-04-28

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve the existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.

  5. Technology Trumping Sleep: Impact of Electronic Media and Sleep in Late Adolescent Students

    ERIC Educational Resources Information Center

    Moulin, Kerry L.; Chung, Chia-Jung

    2017-01-01

    The purpose of this research study was to explore with what impact evening media use interfered with either schoolwork and/or sufficient healthy sleep. In addition, the study examined with what impact there may be a compromise in students' ability or aptitude for positive academic success, related to either lack of sleep or electronic media use.…

  6. Electronic distractions of the respiratory therapist and their impact on patient safety.

    PubMed

    Papadakos, Peter J

    2014-08-01

    Over the last decade, data from the lay press, government agencies, and the business world have identified ever-growing problems with electronic distraction and changes in human relationships in this electronically interconnected planet. As health professionals, we are well aware of the epidemic growth of injuries and deaths related to texting and driving. It should not surprise us that this distracted behavior has affected all levels of health-care providers and has impacted patient care. This advent of “distracted doctoring” was first coined by the Pulitzer Prize-winning correspondent Matt Richtel in a landmark article in the New York Times, “As doctors use more devices, potential for distraction grows.” This article was a flashpoint for professional organizations to reflect on this change in behavior and how it will impact patient safety and how we relate to patients. The explosion in technology (both personnel and hospital-based), coupled with a rapid social shift, creates an environment that constantly tempts health-care workers to surf the internet, check social media outlets, or respond to e-mails. Studies and commentaries in the medical literature only support how this is a growing problem in patient safety and may both increase medical errors and affects costs and the way we relate to patients and fellow staff. The Emergency Care Research Institute (ECRI) released its annual list of technology hazards for 2013, and three ring true for United States caregivers: distractions from smartphones and mobile devices, alarm hazards, and patient/data mismatches in electronic medical records and other health IT systems, all being in the top 10. How do we begin to address these new technological threats to our patients? First and foremost, we accept that this problem exists. We begin by educating our students and staff that this electronic explosion affects our behavior through addiction and the environment within our hospital through the use of electronic

  7. Novalis' Poetic Uncertainty: A "Bildung" with the Absolute

    ERIC Educational Resources Information Center

    Mika, Carl

    2016-01-01

    Novalis, the Early German Romantic poet and philosopher, had at the core of his work a mysterious depiction of the "absolute." The absolute is Novalis' name for a substance that defies precise knowledge yet calls for a tentative and sensitive speculation. How one asserts a truth, represents an object, and sets about encountering things…

  8. Absolute marine gravimetry with matter-wave interferometry.

    PubMed

    Bidel, Y; Zahzam, N; Blanchard, C; Bonnin, A; Cadoret, M; Bresson, A; Rouxel, D; Lequentrec-Lalancette, M F

    2018-02-12

    Measuring gravity from an aircraft or a ship is essential in geodesy, geophysics, mineral and hydrocarbon exploration, and navigation. Today, only relative sensors are available for onboard gravimetry. This is a major drawback because of the calibration and drift estimation procedures which lead to important operational constraints. Atom interferometry is a promising technology to obtain onboard absolute gravimeter. But, despite high performances obtained in static condition, no precise measurements were reported in dynamic. Here, we present absolute gravity measurements from a ship with a sensor based on atom interferometry. Despite rough sea conditions, we obtained precision below 10 -5  m s -2 . The atom gravimeter was also compared with a commercial spring gravimeter and showed better performances. This demonstration opens the way to the next generation of inertial sensors (accelerometer, gyroscope) based on atom interferometry which should provide high-precision absolute measurements from a moving platform.

  9. Electron-impact electronic-state excitation of para-benzoquinone

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; da Costa, R. F.; Kossoski, F.; Varella, M. T. do N.; Bettega, M. H. F.; Ferreira da Silva, F.; Limão-Vieira, P.; García, G.; Lima, M. A. P.; White, R. D.; Brunger, M. J.

    2018-03-01

    Angle resolved electron energy loss spectra (EELS) for para-benzoquinone (C6H4O2) have been recorded for incident electron energies of 20, 30, and 40 eV. Measured differential cross sections (DCSs) for electronic band features, composed of a combination of energetically unresolved electronic states, are subsequently derived from those EELS. Where possible, the obtained DCSs are compared with those calculated using the Schwinger multichannel method with pseudopotentials. These calculations were performed using a minimum orbital basis single configuration interaction framework at the static exchange plus polarisation level. Here, quite reasonable agreement between the experimental cross sections and the theoretical cross sections for the summation of unresolved states was observed.

  10. The absolute dynamic ocean topography (ADOT)

    NASA Astrophysics Data System (ADS)

    Bosch, Wolfgang; Savcenko, Roman

    The sea surface slopes relative to the geoid (an equipotential surface) basically carry the in-formation on the absolute velocity field of the surface circulation. Pure oceanographic models may remain unspecific with respect to the absolute level of the ocean topography. In contrast, the geodetic approach to estimate the ocean topography as difference between sea level and the geoid gives by definition an absolute dynamic ocean topography (ADOT). This approach requires, however, a consistent treatment of geoid and sea surface heights, the first being usually derived from a band limited spherical harmonic series of the Earth gravity field and the second observed with much higher spectral resolution by satellite altimetry. The present contribution shows a procedure for estimating the ADOT along the altimeter profiles, preserving as much sea surface height details as the consistency w.r.t. the geoid heights will allow. The consistent treatment at data gaps and the coast is particular demanding and solved by a filter correction. The ADOT profiles are inspected for their innocent properties towards the coast and compared to external estimates of the ocean topography or the velocity field of the surface circulation as derived, for example, by ARGO floats.

  11. Absolute configuration of a chiral CHD group via neutron diffraction: confirmation of the absolute stereochemistry of the enzymatic formation of malic acid

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Bau, R.; Brewer, I.; Chiang, M.Y.

    Neutron diffraction has been used to monitor the absolute stereochemistry of an enzymatic reaction. (-)(2S)malic-3-d acid was prepared by the action of fumarase on fumaric acid in D/sub 2/O. After a large number of cations were screened, it was found that (+)(R)..cap alpha..-phenylethylamine forms the large crystals necessary for a neutron diffraction analysis. The subsequent structure determination showed that (+)(R)..cap alpha..-phenylethylammonium (-)(2S)malate-3-d has an absolute configuration of R at the CHD site. This result confirms the absolute stereochemistry of fumarate-to-malate transformation as catalyzed by the enzyme fumarase.

  12. Clinical implementation of total skin electron irradiation treatment with a 6 MeV electron beam in high-dose total skin electron mode

    NASA Astrophysics Data System (ADS)

    Lucero, J. F.; Rojas, J. I.

    2016-07-01

    Total skin electron irradiation (TSEI) is a special treatment technique offered by modern radiation oncology facilities, given for the treatment of mycosis fungoides, a rare skin disease, which is type of cutaneous T-cell lymphoma [1]. During treatment the patient's entire skin is irradiated with a uniform dose. The aim of this work is to present implementation of total skin electron irradiation treatment using IAEA TRS-398 code of practice for absolute dosimetry and taking advantage of the use of radiochromic films.

  13. The Absolute Magnitude of the Sun in Several Filters

    NASA Astrophysics Data System (ADS)

    Willmer, Christopher N. A.

    2018-06-01

    This paper presents a table with estimates of the absolute magnitude of the Sun and the conversions from vegamag to the AB and ST systems for several wide-band filters used in ground-based and space-based observatories. These estimates use the dustless spectral energy distribution (SED) of Vega, calibrated absolutely using the SED of Sirius, to set the vegamag zero-points and a composite spectrum of the Sun that coadds space-based observations from the ultraviolet to the near-infrared with models of the Solar atmosphere. The uncertainty of the absolute magnitudes is estimated by comparing the synthetic colors with photometric measurements of solar analogs and is found to be ∼0.02 mag. Combined with the uncertainty of ∼2% in the calibration of the Vega SED, the errors of these absolute magnitudes are ∼3%–4%. Using these SEDs, for three of the most utilized filters in extragalactic work the estimated absolute magnitudes of the Sun are M B = 5.44, M V = 4.81, and M K = 3.27 mag in the vegamag system and M B = 5.31, M V = 4.80, and M K = 5.08 mag in AB.

  14. The impact of electronic cigarettes on the paediatric population

    PubMed Central

    Durmowicz, Elizabeth L

    2014-01-01

    Objective To review the impact of electronic cigarettes (e-cigarettes) on children. Methods Five electronic databases were searched through 31 December 2013. Studies in English that included data for children younger than 18 years of age were included. In addition, relevant data from articles identified during searches of the e-cigarette literature, relevant state survey data and paediatric voluntary adverse event reports submitted to the US Food and Drug Administration (FDA) were reviewed and included. Results Use of e-cigarettes by youth is increasing and is not limited to traditional cigarette smokers. Data regarding the reasons for youth e-cigarette initiation and ongoing use are limited. The effects of e-cigarette marketing and the availability of flavoured e-liquids on youth use are unknown. The abuse liability of e-cigarettes in youth is also not known. Unintentional exposures to e-cigarettes and e-liquids have been reported in children. The number of e-cigarette-related reports received by poison centres is increasing. No data are available on secondhand and thirdhand e-cigarette aerosol exposures in children. Conclusions Data on the impact of e-cigarettes on children are extremely limited. The available data indicate that youth awareness is high and use is increasing rapidly. The extent to which e-cigarette use in youth will result in nicotine dependence and subsequent use of other tobacco products is unknown. e-cigarettes present risks of unintentional nicotine exposure and are potential choking hazards. A greater understanding of the impact of e-cigarettes on children is needed and will be important in the evaluation of the effects of these products on the public health. PMID:24732163

  15. The impact of electronic cigarettes on the paediatric population.

    PubMed

    Durmowicz, Elizabeth L

    2014-05-01

    To review the impact of electronic cigarettes (e-cigarettes) on children. Five electronic databases were searched through 31 December 2013. Studies in English that included data for children younger than 18 years of age were included. In addition, relevant data from articles identified during searches of the e-cigarette literature, relevant state survey data and paediatric voluntary adverse event reports submitted to the US Food and Drug Administration (FDA) were reviewed and included. Use of e-cigarettes by youth is increasing and is not limited to traditional cigarette smokers. Data regarding the reasons for youth e-cigarette initiation and ongoing use are limited. The effects of e-cigarette marketing and the availability of flavoured e-liquids on youth use are unknown. The abuse liability of e-cigarettes in youth is also not known. Unintentional exposures to e-cigarettes and e-liquids have been reported in children. The number of e-cigarette-related reports received by poison centres is increasing. No data are available on secondhand and thirdhand e-cigarette aerosol exposures in children. Data on the impact of e-cigarettes on children are extremely limited. The available data indicate that youth awareness is high and use is increasing rapidly. The extent to which e-cigarette use in youth will result in nicotine dependence and subsequent use of other tobacco products is unknown. e-cigarettes present risks of unintentional nicotine exposure and are potential choking hazards. A greater understanding of the impact of e-cigarettes on children is needed and will be important in the evaluation of the effects of these products on the public health.

  16. Absolute calibration of sniffer probes on Wendelstein 7-X

    NASA Astrophysics Data System (ADS)

    Moseev, D.; Laqua, H. P.; Marsen, S.; Stange, T.; Braune, H.; Erckmann, V.; Gellert, F.; Oosterbeek, J. W.

    2016-08-01

    Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m2 per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m2 per MW injected beam power is measured.

  17. Absolute calibration of sniffer probes on Wendelstein 7-X.

    PubMed

    Moseev, D; Laqua, H P; Marsen, S; Stange, T; Braune, H; Erckmann, V; Gellert, F; Oosterbeek, J W

    2016-08-01

    Here we report the first measurements of the power levels of stray radiation in the vacuum vessel of Wendelstein 7-X using absolutely calibrated sniffer probes. The absolute calibration is achieved by using calibrated sources of stray radiation and the implicit measurement of the quality factor of the Wendelstein 7-X empty vacuum vessel. Normalized absolute calibration coefficients agree with the cross-calibration coefficients that are obtained by the direct measurements, indicating that the measured absolute calibration coefficients and stray radiation levels in the vessel are valid. Close to the launcher, the stray radiation in the empty vessel reaches power levels up to 340 kW/m(2) per MW injected beam power. Furthest away from the launcher, i.e., half a toroidal turn, still 90 kW/m(2) per MW injected beam power is measured.

  18. Preparation of an oakmoss absolute with reduced allergenic potential.

    PubMed

    Ehret, C; Maupetit, P; Petrzilka, M; Klecak, G

    1992-06-01

    Synopsis Oakmoss absolute, an extract of the lichen Evernia prunastri, is known to cause allergenic skin reactions due to the presence of certain aromatic aldehydes such as atranorin, chloratranorin, ethyl hematommate and ethyl chlorohematommate. In this paper it is shown that treatment of Oakmoss absolute with amino acids such as lysine and/or leucine, lowers considerably the content of these allergenic constituents including atranol and chloratranol. The resulting Oakmoss absolute, which exhibits an excellent olfactive quality, was tested extensively in comparative studies on guinea pigs and on man. The results of the Guinea Pig Maximization Test (GPMT) and Human Repeated Insult Patch Test (HRIPT) indicate that, in comparison with the commercial test sample, the allergenicity of this new quality of Oakmoss absolute was considerably reduced, and consequently better skin tolerance of this fragrance for man was achieved.

  19. Electron impact excitation of argon in the extreme vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Mentall, J. E.; Morgan, H. D.

    1976-01-01

    Polarization-free excitation cross sections in the extreme vacuum ultraviolet have been measured for electron impact on Ar. Observed spectral features were those lines of Ar I and Ar II which lie between 700 and 1100 A. Excitation functions were measured for the Ar I resonance line at 1048 A and the Ar II resonance line at 920 A. Peak cross sections for these two lines were found to be (39.4 plus or minus 7.9) x 10 to the -18th and (6.9 plus or minus 1.4) x 10 to the -18th, respectively. At low energies, excitation of the Ar II resonance line is dominated by an electron exchange transition.

  20. Electron-impact excitation of Rydberg and valence electronic states of nitric oxide: II. Integral cross sections

    NASA Astrophysics Data System (ADS)

    Brunger, M. J.; Campbell, L.; Cartwright, D. C.; Middleton, A. G.; Mojarrabi, B.; Teubner, P. J. O.

    2000-02-01

    Integral cross sections (ICSs) for the excitation of 18 excited electronic states, and four composite excited electronic states, in nitric oxide (NO) have been determined for incident electron energies of 15, 20, 30, 40 and 50 eV. These ICSs were derived by extrapolating the respective measured differential cross sections (M J Brunger et al 2000 J. Phys. B: At. Mol. Opt. Phys. 33 783) to 0° and 180° and by performing the appropriate integration. Comparison of the present ICSs with the results of those determined in earlier optical emission measurements, and from theoretical calculations is made. At each incident energy considered, the current ICSs are also summed along with the corresponding elastic and rovibrational excitation ICSs from B Mojarrabi et al (1995 J. Phys. B: At. Mol. Opt. Phys. 28 487) and the ionization cross sections from Rapp and Englander-Golden (1965 J. Chem. Phys. 43 1464), to derive an estimate of the grand total cross sections (GTSs) for e- + NO scattering. The GTSs derived in this manner are compared with the results from independent linear transmission experiments and are found to be entirely consistent with them. The present excited electronic state ICS, and those for elastic and rovibrational excitation from Mojarrabi et al , appear to represent the first set of self-consistent cross sections for electron impact scattering from NO.

  1. Nonequilibrium calculations of the role of electron impact in the production of NO and its emissions

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Brunger, M. J.

    2009-04-01

    We review our recent work on nonequilibrium modelling of the density of nitric oxide and its infrared emissions in the Earth's upper atmosphere. The aim of these studies was to investigate the contribution of electron impact excitation to the NO density and the sensitivity of this process to the electron impact cross sections. The results are compared with satellite measurements of NO densities in equatorial and auroral high-latitude conditions and with rocket measurements of infrared emissions in auroral conditions. Particular findings are that electron impact excitation of N2 makes a significant contribution to the NO density at altitudes around 105 km and to auroral infrared emissions for the (1 → 0) ground-state emission from NO. The sensitivity of the NO fundamental emissions to various measured and theoretical integral cross sections is investigated and found to be significant.

  2. Physics of negative absolute temperatures.

    PubMed

    Abraham, Eitan; Penrose, Oliver

    2017-01-01

    Negative absolute temperatures were introduced into experimental physics by Purcell and Pound, who successfully applied this concept to nuclear spins; nevertheless, the concept has proved controversial: a recent article aroused considerable interest by its claim, based on a classical entropy formula (the "volume entropy") due to Gibbs, that negative temperatures violated basic principles of statistical thermodynamics. Here we give a thermodynamic analysis that confirms the negative-temperature interpretation of the Purcell-Pound experiments. We also examine the principal arguments that have been advanced against the negative temperature concept; we find that these arguments are not logically compelling, and moreover that the underlying "volume" entropy formula leads to predictions inconsistent with existing experimental results on nuclear spins. We conclude that, despite the counterarguments, negative absolute temperatures make good theoretical sense and did occur in the experiments designed to produce them.

  3. Carbon contamination in scanning transmission electron microscopy and its impact on phase-plate applications.

    PubMed

    Hettler, Simon; Dries, Manuel; Hermann, Peter; Obermair, Martin; Gerthsen, Dagmar; Malac, Marek

    2017-05-01

    We analyze electron-beam induced carbon contamination in a transmission electron microscope. The study is performed on thin films potentially suitable as phase plates for phase-contrast transmission electron microscopy. Electron energy-loss spectroscopy and phase-plate imaging is utilized to analyze the contamination. The deposited contamination layer is identified as a graphitic carbon layer which is not prone to electrostatic charging whereas a non-conductive underlying substrate charges. Several methods that inhibit contamination are evaluated and the impact of carbon contamination on phase-plate imaging is discussed. The findings are in general interesting for scanning transmission electron microscopy applications. Crown Copyright © 2017. Published by Elsevier Ltd. All rights reserved.

  4. Advances in the Metrology of Absolute Value Assignments to Isotopic Reference Materials: Consequences from the Avogadro Project

    NASA Astrophysics Data System (ADS)

    Vocke, Robert; Rabb, Savelas

    2015-04-01

    All isotope amount ratios (hereafter referred to as isotope ratios) produced and measured on any mass spectrometer are biased. This unfortunate situation results mainly from the physical processes in the source area where ions are produced. Because the ionized atoms in poly-isotopic elements have different masses, such processes are typically mass dependent and lead to what is commonly referred to as mass fractionation (for thermal ionization and electron impact sources) and mass bias (for inductively coupled plasma sources.) This biasing process produces a measured isotope ratio that is either larger or smaller than the "true" ratio in the sample. This has led to the development of numerous fractionation "laws" that seek to correct for these effects, many of which are not based on the physical processes giving rise to the biases. The search for tighter and reproducible precisions has led to two isotope ratio measurement systems that exist side-by-side. One still seeks to measure "absolute" isotope ratios while the other utilizes an artifact based measurement system called a delta-scale. The common element between these two measurement systems is the utilization of isotope reference materials (iRMs). These iRMs are used to validate a fractionation "law" in the former case and function as a scale anchor in the latter. Many value assignments of iRMs are based on "best measurements" by the original groups producing the reference material, a not entirely satisfactory approach. Other iRMs, with absolute isotope ratio values, have been produced by calibrated measurements following the Atomic Weight approach (AW) pioneered by NBS nearly 50 years ago. Unfortunately, the AW is not capable of calibrating the new generation of iRMs to sufficient precision. So how do we get iRMs with isotope ratios of sufficient precision and without bias? Such a focus is not to denigrate the extremely precise delta-scale measurements presently being made on non-traditional and tradition

  5. Absolute gravimetry for monitoring geodynamics in Greenland.

    NASA Astrophysics Data System (ADS)

    Nielsen, E.; Strykowski, G.; Forsberg, R.

    2015-12-01

    Here are presented the preliminary results of the absolute gravity measurements done in Greenland by DTU Space with their A10 absolute gravimeter (the A10-019). The purpose, besides establishing and maintaining a national gravity network, is to study geodynamics.The absolute gravity measurements are juxtaposed with the permanent GNET GNSS stations. The first measurements were conducted in 2009 and a few sites have been re-visited. As of present is there a gravity value at 18 GNET sites.There are challenges in interpreting the measurements from Greenland and several signals has to be taken into account, besides the geodynamical signals originating from the changing load of the ice, there is also a clear signal of direct attraction from different masses. Here are presented the preliminary results of our measurements in Greenland and attempts explain them through modelling of the geodynamical signals and the direct attraction from the ocean and ice.

  6. Absolute Calibration of the AXAF Telescope Effective Area

    NASA Technical Reports Server (NTRS)

    Kellogg, E.; Cohen, L.; Edgar, R.; Evans, I.; Freeman, M.; Gaetz, T.; Jerius, D.; McDermott, W. C.; McKinnon, P.; Murray, S.; hide

    1997-01-01

    The prelaunch calibration of AXAF encompasses many aspects of the telescope. In principle, all that is needed is the complete point response function. This is, however, a function of energy, off-axis angle of the source, and operating mode of the facility. No single measurement would yield the entire result. Also, any calibration made prior to launch will be affected by changes in conditions after launch, such as the change from one g to zero g. The reflectivity of the mirror and perhaps even the detectors can change as well, for example by addition or removal of small amounts of material deposited on their surfaces. In this paper, we give a broad view of the issues in performing such a calibration, and discuss how they are being addressed in prelaunch preparation of AXAF. As our title indicates, we concentrate here on the total throughput of the observatory. This can be thought of as the integral of the point response function, i.e. the encircled energy, out ot the largest practical solid angle for an observation. Since there is no standard x-ray source in the sky whose flux is known to the -1% accuracy we are trying to achieve, we must do this calibration on the ground. we also must provide a means for monitoring any possible changes in this calibration from pre-launch until on-orbit operation can transfer the calibration to a celestial x-ray source whose emission is stable. In this paper, we analyze the elements of the absolute throughput calibration, which we call Effective Area. We review the requirements for calibrations of components or subsystems of the AXAF facility, including mirror, detectors, and gratings. We show how it is necessary to calibrate this ground-based detection system at standard man-made x-ray sources, such as electron storage rings. We present the status of all these calibrations, with indications of the measurements remaining to be done, even though the measurements on the AXAF flight optics and detectors will have been completed by the

  7. A coincidence study of electron and positron impact ionization of Ar (3p) at 1 keV

    NASA Astrophysics Data System (ADS)

    Campeanu, Radu I.; Walters, James H. R.; Whelan, Colm T.

    2015-10-01

    Distorted-wave calculations of the triple differential cross section (TDCS) are presented for electron and positron impact ionization of Ar(3p) in coplanar asymmetric geometry at an impact energy of 1 keV and are compared with a recent experiment. The experiment indicates that the positron TDCS is generally larger than the equivalent electron TDCS. It is shown that the magnitude of the TDCS is extremely sensitive to the energy of the ejected electron and that only when the cross section is averaged over energy do we get a reasonable agreement with experiment.

  8. Research gaps related to the environmental impacts of electronic cigarettes.

    PubMed

    Chang, Hoshing

    2014-05-01

    To consider the research gaps related to the environmental impacts of electronic cigarettes due to their manufacture, use and disposal. Literature searches were conducted through December 2013. Studies were included in this review if they related to the environmental impacts of e-cigarettes. Scientific information on the environmental impacts of e-cigarette manufacturing, use and disposal is very limited. No studies formally evaluated the environmental impacts of the manufacturing process or disposal of components, including batteries. Four studies evaluated potential exposure to secondhand e-cigarette aerosol, an indication of impacts on indoor air quality. A 2010 survey of six e-cigarette models found that none of the products provided disposal instructions for spent cartridges containing nicotine. Notably, some e-cigarette manufacturers claim their e-cigarettes are 'eco-friendly' or 'green', despite the lack of any supporting data or environmental impact studies. Some authors argue that such advertising may boost sales and increase e-cigarette appeal, especially among adolescents. Little is known about the environmental impacts of e-cigarettes, and a number of topics could be further elucidated by additional investigation. These topics include potential environmental impacts related to manufacturing, use and disposal. The environmental impacts of e-cigarette manufacturing will depend upon factory size and the nicotine extracting method used. The environmental impacts of e-cigarette use will include chemical and aerosol exposure in the indoor environment. The environmental impacts of disposal of e-cigarette cartridges (which contain residual nicotine) and disposal of e-cigarettes (which contain batteries) represent yet another environmental concern.

  9. Research gaps related to the environmental impacts of electronic cigarettes

    PubMed Central

    Chang, Hoshing

    2014-01-01

    Objective To consider the research gaps related to the environmental impacts of electronic cigarettes due to their manufacture, use and disposal. Methods Literature searches were conducted through December 2013. Studies were included in this review if they related to the environmental impacts of e-cigarettes. Results Scientific information on the environmental impacts of e-cigarette manufacturing, use and disposal is very limited. No studies formally evaluated the environmental impacts of the manufacturing process or disposal of components, including batteries. Four studies evaluated potential exposure to secondhand e-cigarette aerosol, an indication of impacts on indoor air quality. A 2010 survey of six e-cigarette models found that none of the products provided disposal instructions for spent cartridges containing nicotine. Notably, some e-cigarette manufacturers claim their e-cigarettes are ‘eco-friendly’ or ‘green’, despite the lack of any supporting data or environmental impact studies. Some authors argue that such advertising may boost sales and increase e-cigarette appeal, especially among adolescents. Conclusions Little is known about the environmental impacts of e-cigarettes, and a number of topics could be further elucidated by additional investigation. These topics include potential environmental impacts related to manufacturing, use and disposal. The environmental impacts of e-cigarette manufacturing will depend upon factory size and the nicotine extracting method used. The environmental impacts of e-cigarette use will include chemical and aerosol exposure in the indoor environment. The environmental impacts of disposal of e-cigarette cartridges (which contain residual nicotine) and disposal of e-cigarettes (which contain batteries) represent yet another environmental concern. PMID:24732165

  10. Strongly nonlinear theory of rapid solidification near absolute stability

    NASA Astrophysics Data System (ADS)

    Kowal, Katarzyna N.; Altieri, Anthony L.; Davis, Stephen H.

    2017-10-01

    We investigate the nonlinear evolution of the morphological deformation of a solid-liquid interface of a binary melt under rapid solidification conditions near two absolute stability limits. The first of these involves the complete stabilization of the system to cellular instabilities as a result of large enough surface energy. We derive nonlinear evolution equations in several limits in this scenario and investigate the effect of interfacial disequilibrium on the nonlinear deformations that arise. In contrast to the morphological stability problem in equilibrium, in which only cellular instabilities appear and only one absolute stability boundary exists, in disequilibrium the system is prone to oscillatory instabilities and a second absolute stability boundary involving attachment kinetics arises. Large enough attachment kinetics stabilize the oscillatory instabilities. We derive a nonlinear evolution equation to describe the nonlinear development of the solid-liquid interface near this oscillatory absolute stability limit. We find that strong asymmetries develop with time. For uniform oscillations, the evolution equation for the interface reduces to the simple form f''+(βf')2+f =0 , where β is the disequilibrium parameter. Lastly, we investigate a distinguished limit near both absolute stability limits in which the system is prone to both cellular and oscillatory instabilities and derive a nonlinear evolution equation that captures the nonlinear deformations in this limit. Common to all these scenarios is the emergence of larger asymmetries in the resulting shapes of the solid-liquid interface with greater departures from equilibrium and larger morphological numbers. The disturbances additionally sharpen near the oscillatory absolute stability boundary, where the interface becomes deep-rooted. The oscillations are time-periodic only for small-enough initial amplitudes and their frequency depends on a single combination of physical parameters, including the

  11. Precise and absolute measurements of complex third-order optical susceptibility

    NASA Astrophysics Data System (ADS)

    Santran, Stephane; Canioni, Lionel; Cardinal, Thierry; Fargin, Evelyne; Le Flem, Gilles; Rouyer, Claude; Sarger, Laurent

    2000-11-01

    We present precise and absolute measurements of full complex third order optical susceptibility on different fused silica and original glasses composed of tellurium, titanium, niobium erbium. These materials are designed to be the key point for applications ranging form high power laser systems to optoelectronics, their nonlinear index of refraction is a major property and thus must be accurately known. Due to the accuracy and sensitivity of our technique, we have been able to find a large dispersion (more than 30%) of the non linear index of fused silica glasses as a function of their processing mode. On the other hand, measurements on tellurium glasses have shown very strong nonlinearities (40 times higher than fused silica), to be linked to the configurations of their cations and anions. Although the titanium and niobium glasses are less nonlinear, they can be promising matrices for addition of luminescent entities like erbium leading to very interesting laser amplification materials. The experimental set-up is a collinear pump-probe (orthogonally polarized) experiment using transient absorption technique. It is built with around a 100 femtosecond laser oscillator. A fast oscillating delay between the pump and the probe allows us to measure the electronic nonlinearity in quasi real-time. This experiment has the following specifications: an absolute measurement accuracy below 10% mainly due to the laser parameters characterization, a relative measurement accuracy of 1% and a resolution less than 5.10-24m2/V2(50 times less than fused silica).

  12. Ensuring long-term stability of infrared camera absolute calibration.

    PubMed

    Kattnig, Alain; Thetas, Sophie; Primot, Jérôme

    2015-07-13

    Absolute calibration of cryogenic 3-5 µm and 8-10 µm infrared cameras is notoriously instable and thus has to be repeated before actual measurements. Moreover, the signal to noise ratio of the imagery is lowered, decreasing its quality. These performances degradations strongly lessen the suitability of Infrared Imaging. These defaults are often blamed on detectors reaching a different "response state" after each return to cryogenic conditions, while accounting for the detrimental effects of imperfect stray light management. We show here that detectors are not to be blamed and that the culprit can also dwell in proximity electronics. We identify an unexpected source of instability in the initial voltage of the integrating capacity of detectors. Then we show that this parameter can be easily measured and taken into account. This way we demonstrate that a one month old calibration of a 3-5 µm camera has retained its validity.

  13. Electron impact ionization in plasma technologies; studies on atomic boron and BN molecule

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Joshi, Foram M., E-mail: foram29@gmail.com; Joshipura, K. N., E-mail: knjoshipura22@gmail.com; Chaudhari, Asha S., E-mail: ashaschaudhari@gmail.com

    2016-05-06

    Electron impact ionization plays important role in plasma technologies. Relevant cross sections on atomic boron are required to understand the erosion processes in fusion experiments. Boronization of plasma exposed surfaces of tokomaks has proved to be an effective way to produce very pure fusion plasmas. This paper reports comprehensive theoretical investigations on electron scattering with atomic Boron and Boron Nitride in solid phases. Presently we determine total ionization cross-section Q{sub ion} and the summed-electronic excitation cross section ΣQ{sub exc} in a standard quantum mechanical formalism called SCOP and CSP-ic methods. Our calculated cross sections are examined as functions of incidentmore » electron energy along with available comparisons.« less

  14. Single impacts of keV fullerene ions on free standing graphene: Emission of ions and electrons from confined volume

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Verkhoturov, Stanislav V.; Geng, Sheng; Schweikert, Emile A., E-mail: schweikert@chem.tamu.edu

    We present the first data from individual C{sub 60} impacting one to four layer graphene at 25 and 50 keV. Negative secondary ions and electrons emitted in transmission were recorded separately from each impact. The yields for C{sub n}{sup −} clusters are above 10% for n ≤ 4, they oscillate with electron affinities and decrease exponentially with n. The result can be explained with the aid of MD simulation as a post-collision process where sufficient vibrational energy is accumulated around the rim of the impact hole for sputtering of carbon clusters. The ionization probability can be estimated by comparing experimentalmore » yields of C{sub n}{sup −} with those of C{sub n}{sup 0} from MD simulation, where it increases exponentially with n. The ionization probability can be approximated with ejecta from a thermally excited (3700 K) rim damped by cluster fragmentation and electron detachment. The experimental electron probability distributions are Poisson-like. On average, three electrons of thermal energies are emitted per impact. The thermal excitation model invoked for C{sub n}{sup −} emission can also explain the emission of electrons. The interaction of C{sub 60} with graphene is fundamentally different from impacts on 3D targets. A key characteristic is the high degree of ionization of the ejecta.« less

  15. Absolute far-ultraviolet spectrophotometry of hot subluminous stars from Voyager

    NASA Technical Reports Server (NTRS)

    Holberg, J. B.; Ali, B.; Carone, T. E.; Polidan, R. S.

    1991-01-01

    Observations, obtained with the Voyager ultraviolet spectrometers, are presented of absolute fluxes for two well-known hot subluminous stars: BD + 28 deg 4211, an sdO, and G191 - B2B, a hot DA white dwarf. Complete absolute energy distributions for these two stars, from the Lyman limit at 912 A to 1 micron, are given. For BD + 28 deg 4211, a single power law closely represents the entire observed energy distribution. For G191 - B2B, a pure hydrogen model atmosphere provides an excellent match to the entire absolute energy distribution. Voyager absolute fluxes are discussed in relation to those reported from various sounding rocket experiments, including a recent rocket observation of BD + 28 deg 4211.

  16. Communication: Electron ionization of DNA bases

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Rahman, M. A.; Krishnakumar, E., E-mail: ekkumar@tifr.res.in

    2016-04-28

    No reliable experimental data exist for the partial and total electron ionization cross sections for DNA bases, which are very crucial for modeling radiation damage in genetic material of living cell. We have measured a complete set of absolute partial electron ionization cross sections up to 500 eV for DNA bases for the first time by using the relative flow technique. These partial cross sections are summed to obtain total ion cross sections for all the four bases and are compared with the existing theoretical calculations and the only set of measured absolute cross sections. Our measurements clearly resolve themore » existing discrepancy between the theoretical and experimental results, thereby providing for the first time reliable numbers for partial and total ion cross sections for these molecules. The results on fragmentation analysis of adenine supports the theory of its formation in space.« less

  17. Rapid, absolute calibration of x-ray filters employed by laser-produced plasma diagnostics

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Brown, G. V.; Beiersdorfer, P.; Emig, J.

    2008-10-15

    The Electron Beam Ion Trap (EBIT) facility at the Lawrence Livermore National Laboratory is being used to absolutely calibrate the transmission efficiency of x-ray filters employed by diodes and spectrometers used to diagnose laser-produced plasmas. EBIT emits strong, discrete monoenergetic lines at appropriately chosen x-ray energies. X rays are detected using the high resolution EBIT Calorimeter Spectrometer (ECS), developed for LLNL at the NASA/Goddard Space Flight Center. X-ray filter transmission efficiency is determined by dividing the x-ray counts detected when the filter is in the line of sight by those detected when out of the line of sight. Verification ofmore » filter thickness can be completed in only a few hours, and absolute efficiencies can be calibrated in a single day over a broad range from about 0.1 to 15 keV. The EBIT calibration lab has been used to field diagnostics (e.g., the OZSPEC instrument) with fully calibrated x-ray filters at the OMEGA laser. Extensions to use the capability for calibrating filter transmission for the DANTE instrument on the National Ignition Facility are discussed.« less

  18. Limitations of silicon diodes for clinical electron dosimetry.

    PubMed

    Song, Haijun; Ahmad, Munir; Deng, Jun; Chen, Zhe; Yue, Ning J; Nath, Ravinder

    2006-01-01

    This work investigates the relevance of several factors affecting the response of silicon diode dosemeters in depth-dose scans of electron beams. These factors are electron energy, instantaneous dose rate, dose per pulse, photon/electron dose ratio and electron scattering angle (directional response). Data from the literature and our own experiments indicate that the impact of these factors may be up to +/-15%. Thus, the different factors would have to cancel out perfectly at all depths in order to produce true depth-dose curves. There are reports of good agreement between depth-doses measured with diodes and ionisation chambers. However, our measurements with a Scantronix electron field detector (EFD) diode and with a plane-parallel ionisation chamber show discrepancies both in the build-up and in the low-dose regions, with a ratio up to 1.4. Moreover, the absolute sensitivity of two diodes of the same EFD model was found to differ by a factor of 3, and this ratio was not constant but changed with depth between 5 and 15% in the low-dose regions of some clinical electron beams. Owing to these inhomogeneities among diodes even of the same model, corrections for each factor would have to be diode-specific and beam-specific. All these corrections would have to be determined using parallel plane chambers, as recommended by AAPM TG-25, which would be unrealistic in clinical practice. Our conclusion is that in general diodes are not reliable in the measurement of depth-dose curves of clinical electron beams.

  19. From Hubble's NGSL to Absolute Fluxes

    NASA Technical Reports Server (NTRS)

    Heap, Sara R.; Lindler, Don

    2012-01-01

    Hubble's Next Generation Spectral Library (NGSL) consists of R-l000 spectra of 374 stars of assorted temperature, gravity, and metallicity. Each spectrum covers the wavelength range, 0.18-1.00 microns. The library can be viewed and/or downloaded from the website, http://archive.stsci.edu/prepds/stisngsll. Stars in the NGSL are now being used as absolute flux standards at ground-based observatories. However, the uncertainty in the absolute flux is about 2%, which does not meet the requirements of dark-energy surveys. We are therefore developing an observing procedure that should yield fluxes with uncertainties less than 1 % and will take part in an HST proposal to observe up to 15 stars using this new procedure.

  20. Absolute calibration of optical flats

    DOEpatents

    Sommargren, Gary E.

    2005-04-05

    The invention uses the phase shifting diffraction interferometer (PSDI) to provide a true point-by-point measurement of absolute flatness over the surface of optical flats. Beams exiting the fiber optics in a PSDI have perfect spherical wavefronts. The measurement beam is reflected from the optical flat and passed through an auxiliary optic to then be combined with the reference beam on a CCD. The combined beams include phase errors due to both the optic under test and the auxiliary optic. Standard phase extraction algorithms are used to calculate this combined phase error. The optical flat is then removed from the system and the measurement fiber is moved to recombine the two beams. The newly combined beams include only the phase errors due to the auxiliary optic. When the second phase measurement is subtracted from the first phase measurement, the absolute phase error of the optical flat is obtained.

  1. Dissociation of CH4 by electron impact: Production of metastable hydrogen and carbon fragments

    NASA Technical Reports Server (NTRS)

    Finn, T. G.; Carnahan, B. L.; Zipf, E. C.

    1974-01-01

    Metastable fragments produced by electron impact excitation of CH4 have been investigated for incident electron energies from threshold to 300 eV. Only metastable hydrogen and carbon atoms were observed. Onset energies for the production of metastable hydrogen atoms were observed at electron impact energies of 22.0 + or - .5 eV, 25.5 + or - .6 eV, 36.7 + or - .6 eV and 66 + or - 3 eV, and at 26.6 + or - .6 eV for the production of metastable carbon atoms. Most of the fragments appear to have been formed in high-lying Rydberg states. The total metastable hydrogen cross section reaches a maximum value of approximately 1 X 10 to the minus 18th power sq cm at 100 eV. At the same energy, the metastable carbon cross section is 2 x 10 to the minus 19th power sq cm.

  2. The electronic states of cyclopropane studied by VUV absorption and electron energy-loss spectroscopies

    NASA Astrophysics Data System (ADS)

    Gingell, M.; Mason, N. J.; Walker, I. C.; Marston, G.; Zhao, H.; Siggel, M. R. F.

    1999-06-01

    Absolute optical (VUV) absorption cross sections for cyclopropane have been measured from 5.0 to 11.2 and 20-40 eV using synchrotron radiation. Also, electron energy-loss (EEL) spectra have been obtained using incident electrons of (a) 150 eV energy scattered through small angles (energy loss 5.0-15 eV) and (b) near-threshold energies scattered through large angles (energy loss 0-10.5 eV). Taken together these confirm that the low-lying excited electronic states of cyclopropane are of Rydberg type and, although spectral bands are diffuse, a known Rydberg series has been extended. Recent computations (Galasso V 1996 Chem. Phys. 206 289) appear to give a good account of the experimental spectrum from threshold to about 11 eV, but these must be extended if valence-excited states are to be characterized. Particular attention has been directed at the evaluation of absolute optical cross sections. These are now believed to be established over the energy ranges 5-15 and 20-40 eV. In the gap region (15-20 eV) second-order radiation may affect the optical measurements. From consideration of second-order effects, and comparison of the present studies with earlier measurements, we propose a best-estimate cross section in this energy region also.

  3. Electron impact ionization from p-orbital targets

    NASA Astrophysics Data System (ADS)

    Saha, Bidhan; Basak, Arun K.; Alfaz Uddin, M.

    2006-05-01

    Electron impact ionization cross sections are evaluated using a modified version [1] of the BELL formula [2] for a wide range of isoelectronic targets, ranging from Li to Ne targets with both the open and closed shell configurations. In this report the MBELL parameters are generalized for treating the orbital quantum numbers nl dependency; its accuracy has been tested by evaluating cross sections for a wider range of species and energies. Details will be presented at the meeting. [1] A. K. F. Haque, M. A. Uddin, A. K. Basak, K. R. Karim and B. C. Saha, Phys. Rev. A73, 012708 (2005). [2] K. L. Bell, H. B. Gilbody, J. G. Hughes, A. E. Kingston, and F. J. Smith, J. Phys. Chem. Ref. Data 12, 891 (1983).

  4. Electron-electron correlation in two-photon double ionization of He-like ions

    NASA Astrophysics Data System (ADS)

    Hu, S. X.

    2018-01-01

    Electron correlation plays a crucial role in quantum many-body physics ranging from molecular bonding and strong-field-induced multielectron ionization, to superconducting in materials. Understanding the dynamic electron correlation in the photoionization of relatively simple quantum three-body systems, such as He and He-like ions, is an important step toward manipulating complex systems through photoinduced processes. Here we have performed ab initio investigations of two-photon double ionization (TPDI) of He and He-like ions (L i+,B e2 + , and C4 +) exposed to intense attosecond x-ray pulses. Results from such fully correlated quantum calculations show weaker and weaker electron correlation effects in TPDI spectra as the ionic charge increases, which is opposite to the intuition that the absolute increase of correlation in the ground state should lead to more equal energy sharing in photoionization. These findings indicate that the final-state electron-electron correlation ultimately determines the energy sharing of the two ionized electrons in TPDI.

  5. Probative value of absolute and relative judgments in eyewitness identification.

    PubMed

    Clark, Steven E; Erickson, Michael A; Breneman, Jesse

    2011-10-01

    It is well-accepted that eyewitness identification decisions based on relative judgments are less accurate than identification decisions based on absolute judgments. However, the theoretical foundation for this view has not been established. In this study relative and absolute judgments were compared through simulations of the WITNESS model (Clark, Appl Cogn Psychol 17:629-654, 2003) to address the question: Do suspect identifications based on absolute judgments have higher probative value than suspect identifications based on relative judgments? Simulations of the WITNESS model showed a consistent advantage for absolute judgments over relative judgments for suspect-matched lineups. However, simulations of same-foils lineups showed a complex interaction based on the accuracy of memory and the similarity relationships among lineup members.

  6. Electron impact cross-sections and cooling rates for methane. [in thermal balance of electrons in atmospheres and ionospheres of planets and satellites in outer solar system

    NASA Technical Reports Server (NTRS)

    Gan, L.; Cravens, T. E.

    1992-01-01

    Energy transfer between electrons and methane gas by collisional processes plays an important role in the thermal balance of electrons in the atmospheres and ionospheres of planets and satellites in the outer solar system. The literature is reviewed for electron impact cross-sections for methane in this paper. Energy transfer rates are calculated for elastic and inelastic processes using a Maxwellian electron distribution. Vibrational, rotational, and electronic excitation and ionization are included. Results are presented for a wide range of electron temperatures and neutral temperatures.

  7. Measurements of Charging of Apollo 17 Lunar Dust Grains by Electron Impact

    NASA Technical Reports Server (NTRS)

    Abbas, Mian M.; Tankosic, Dragana; Spann, James F.; Dube, Michael J.

    2008-01-01

    It is well known since the Apollo missions that the lunar surface is covered with a thick layer of micron size dust grains with unusually high adhesive characteristics. The dust grains observed to be levitated and transported on the lunar surface are believed to have a hazardous impact on the robotic and human missions to the Moon. The observed dust phenomena are attributed to the lunar dust being charged positively during the day by UV photoelectric emissions, and negatively during the night by the solar wind electrons. The current dust charging and the levitation models, however, do not fully explain the observed phenomena, with the uncertainty of dust charging processes and the equilibrium potentials of the individual dust grains. It is well recognized that the charging properties of individual dust grains are substantially different from those determined from measurements made on bulk materials that are currently available. An experimental facility has been developed in the Dusty Plasma Laboratory at MSFC for investigating the charging and optical properties of individual micron/sub-micron size positively or negatively charged dust grains by levitating them in an electrodynamic balance in simulated space environments. In this paper, we present the laboratory measurements on charging of Apollo 17 individual lunar dust grains by a low energy electron beam. The charging rates and the equilibrium potentials produced by direct electron impact and by secondary electron emission process are discussed.

  8. Determination of Absolute Zero Using a Computer-Based Laboratory

    ERIC Educational Resources Information Center

    Amrani, D.

    2007-01-01

    We present a simple computer-based laboratory experiment for evaluating absolute zero in degrees Celsius, which can be performed in college and undergraduate physical sciences laboratory courses. With a computer, absolute zero apparatus can help demonstrators or students to observe the relationship between temperature and pressure and use…

  9. Computationally Aided Absolute Stereochemical Determination of Enantioenriched Amines.

    PubMed

    Zhang, Jun; Gholami, Hadi; Ding, Xinliang; Chun, Minji; Vasileiou, Chrysoula; Nehira, Tatsuo; Borhan, Babak

    2017-03-17

    A simple and efficient protocol for sensing the absolute stereochemistry and enantiomeric excess of chiral monoamines is reported. Preparation of the sample requires a single-step reaction of the 1,1'-(bromomethylene)dinaphthalene (BDN) with the chiral amine. Analysis of the exciton coupled circular dichroism generated from the BDN-derivatized chiral amine sample, along with comparison to conformational analysis performed computationally, yields the absolute stereochemistry of the parent chiral monoamine.

  10. Use of Absolute and Comparative Performance Feedback in Absolute and Comparative Judgments and Decisions

    ERIC Educational Resources Information Center

    Moore, Don A.; Klein, William M. P.

    2008-01-01

    Which matters more--beliefs about absolute ability or ability relative to others? This study set out to compare the effects of such beliefs on satisfaction with performance, self-evaluations, and bets on future performance. In Experiment 1, undergraduate participants were told they had answered 20% correct, 80% correct, or were not given their…

  11. A Special Application of Absolute Value Techniques in Authentic Problem Solving

    ERIC Educational Resources Information Center

    Stupel, Moshe

    2013-01-01

    There are at least five different equivalent definitions of the absolute value concept. In instances where the task is an equation or inequality with only one or two absolute value expressions, it is a worthy educational experience for learners to solve the task using each one of the definitions. On the other hand, if more than two absolute value…

  12. Absolute iron deficiency without anaemia in patients with chronic systolic heart failure is associated with poorer functional capacity.

    PubMed

    Pozzo, Joffrey; Fournier, Pauline; Delmas, Clément; Vervueren, Paul-Louis; Roncalli, Jérôme; Elbaz, Meyer; Galinier, Michel; Lairez, Olivier

    2017-02-01

    Functional status is one of the main concerns in the management of heart failure (HF). Recently, the FAIR-HF and CONFIRM-HF trials showed that correcting anaemia using intravenous iron supplementation improved functional variables in patients with absolute or relative iron deficiency. Relative iron deficiency is supposed to be a marker of HF severity, as ferritin concentration increases with advanced stages of HF, but little is known about the impact of absolute iron deficiency (AID). To study the impact of AID on functional variables and survival in patients with chronic systolic HF. One hundred and thirty-eight non-anaemic patients with chronic systolic HF were included retrospectively. Patients were divided into two groups according to iron status: the AID group, defined by a ferritin concentration<100μg/L and the non-AID group, defined by a ferritin concentration≥100μg/L. Functional, morphological and biological variables were collected, and survival was assessed. Patients in the AID group had a poorer 6-minute walking test (342 vs. 387m; P=0.03) and poorer peak exercise oxygen consumption (13.8 vs. 16.0mL/min/kg; P=0.01). By multivariable analysis, ferritin<100μg/L was associated with impaired capacity of effort, assessed by peak exercise oxygen consumption. By multivariable analysis, there was no difference in total mortality between groups, with a mean follow-up of 5.1±1.1 years. The poorer functional evaluations in iron-deficient patients previously reported are not caused by the merging of two different populations (i.e. patients with absolute or relative iron deficiency). Our study has confirmed that non-anaemic HF patients with AID have poorer peak oxygen consumption. However, AID has no impact on the survival of these patients. Copyright © 2017. Published by Elsevier Masson SAS.

  13. Bio-Inspired Stretchable Absolute Pressure Sensor Network

    PubMed Central

    Guo, Yue; Li, Yu-Hung; Guo, Zhiqiang; Kim, Kyunglok; Chang, Fu-Kuo; Wang, Shan X.

    2016-01-01

    A bio-inspired absolute pressure sensor network has been developed. Absolute pressure sensors, distributed on multiple silicon islands, are connected as a network by stretchable polyimide wires. This sensor network, made on a 4’’ wafer, has 77 nodes and can be mounted on various curved surfaces to cover an area up to 0.64 m × 0.64 m, which is 100 times larger than its original size. Due to Micro Electro-Mechanical system (MEMS) surface micromachining technology, ultrathin sensing nodes can be realized with thicknesses of less than 100 µm. Additionally, good linearity and high sensitivity (~14 mV/V/bar) have been achieved. Since the MEMS sensor process has also been well integrated with a flexible polymer substrate process, the entire sensor network can be fabricated in a time-efficient and cost-effective manner. Moreover, an accurate pressure contour can be obtained from the sensor network. Therefore, this absolute pressure sensor network holds significant promise for smart vehicle applications, especially for unmanned aerial vehicles. PMID:26729134

  14. On the Perceptual Subprocess of Absolute Pitch.

    PubMed

    Kim, Seung-Goo; Knösche, Thomas R

    2017-01-01

    Absolute pitch (AP) is the rare ability of musicians to identify the pitch of tonal sound without external reference. While there have been behavioral and neuroimaging studies on the characteristics of AP, how the AP is implemented in human brains remains largely unknown. AP can be viewed as comprising of two subprocesses: perceptual (processing auditory input to extract a pitch chroma) and associative (linking an auditory representation of pitch chroma with a verbal/non-verbal label). In this review, we focus on the nature of the perceptual subprocess of AP. Two different models on how the perceptual subprocess works have been proposed: either via absolute pitch categorization (APC) or based on absolute pitch memory (APM). A major distinction between the two views is that whether the AP uses unique auditory processing (i.e., APC) that exists only in musicians with AP or it is rooted in a common phenomenon (i.e., APM), only with heightened efficiency. We review relevant behavioral and neuroimaging evidence that supports each notion. Lastly, we list open questions and potential ideas to address them.

  15. On the Perceptual Subprocess of Absolute Pitch

    PubMed Central

    Kim, Seung-Goo; Knösche, Thomas R.

    2017-01-01

    Absolute pitch (AP) is the rare ability of musicians to identify the pitch of tonal sound without external reference. While there have been behavioral and neuroimaging studies on the characteristics of AP, how the AP is implemented in human brains remains largely unknown. AP can be viewed as comprising of two subprocesses: perceptual (processing auditory input to extract a pitch chroma) and associative (linking an auditory representation of pitch chroma with a verbal/non-verbal label). In this review, we focus on the nature of the perceptual subprocess of AP. Two different models on how the perceptual subprocess works have been proposed: either via absolute pitch categorization (APC) or based on absolute pitch memory (APM). A major distinction between the two views is that whether the AP uses unique auditory processing (i.e., APC) that exists only in musicians with AP or it is rooted in a common phenomenon (i.e., APM), only with heightened efficiency. We review relevant behavioral and neuroimaging evidence that supports each notion. Lastly, we list open questions and potential ideas to address them. PMID:29085275

  16. The Impact of Electronic Mind Maps on Students' Reading Comprehension

    ERIC Educational Resources Information Center

    Mohaidat, Mohammad Mahmoud Talal

    2018-01-01

    This study aimed to investigate the impact of the electronic mind map (IMindMap) on the development of reading comprehension among the ninth grade students in Jordan. The sample of the study consisted of two ninth grade sections from two public schools in Irbid First Directorate during the academic 2016-2017. Each section consisted of (30)…

  17. Absolute configuration in 4-alkyl- and 4-aryl-3,4-dihydro-2(1H)-pyrimidones: a combined theoretical and experimental investigation.

    PubMed

    Uray, G; Verdino, P; Belaj, F; Kappe, C O; Fabian, W M

    2001-10-05

    Structural features (orientation of the carboxyl group, ring puckering), electronic absorption, and circular dichroism spectra of 4-alkyl- and 4-aryl-dihydropyrimidones 1-5 are calculated by semiempirical (AM1, INDO/S), ab initio (HF/6-31G, CIS/6-31G, RPA/6-31G), and density functional theory (B3LYP/6-31G) methods. These calculations allow an assignment of the absolute configuration by comparison of simulated and experimental CD spectra. Although the ab initio methods greatly overestimate electronic transition energies, the general appearance of the experimental CD spectra is quite nicely reproduced by these calculations. Thus, comparison of experimental with calculated CD spectra is a reliable tool for the assignment of the absolute configuration. For 4-methyl derivatives 1, the first enantiopure DHPM examples with no additional aromatic substituent, the stereochemistry at C4 provided by the theoretical results is confirmed by X-ray structure determination of the diastereomeric salt 6. Additional support is the consistent HPLC elution order found for all investigated DHPMs on a cellulose-derived chiral stationary phase.

  18. Relativistic quantum mechanical calculations of electron-impact broadening for spectral lines in Be-like ions

    NASA Astrophysics Data System (ADS)

    Duan, B.; Bari, M. A.; Wu, Z. Q.; Jun, Y.; Li, Y. M.; Wang, J. G.

    2012-11-01

    Aims: We present relativistic quantum mechanical calculations of electron-impact broadening of the singlet and triplet transition 2s3s ← 2s3p in four Be-like ions from N IV to Ne VII. Methods: In our theoretical calculations, the K-matrix and related symmetry information determined by the colliding systems are generated by the DARC codes. Results: A careful comparison between our calculations and experimental results shows good agreement. Our calculated widths of spectral lines also agree with earlier theoretical results. Our investigations provide new methods of calculating electron-impact broadening parameters for plasma diagnostics.

  19. Moral absolutism and ectopic pregnancy.

    PubMed

    Kaczor, C

    2001-02-01

    If one accepts a version of absolutism that excludes the intentional killing of any innocent human person from conception to natural death, ectopic pregnancy poses vexing difficulties. Given that the embryonic life almost certainly will die anyway, how can one retain one's moral principle and yet adequately respond to a situation that gravely threatens the life of the mother and her future fertility? The four options of treatment most often discussed in the literature are non-intervention, salpingectomy (removal of tube with embryo), salpingostomy (removal of embryo alone), and use of methotrexate (MXT). In this essay, I review these four options and introduce a fifth (the milking technique). In order to assess these options in terms of the absolutism mentioned, it will also be necessary to discuss various accounts of the intention/foresight distinction. I conclude that salpingectomy, salpingostomy, and the milking technique are compatible with absolutist presuppositions, but not the use of methotrexate.

  20. Thickness determination of few-layer hexagonal boron nitride films by scanning electron microscopy and Auger electron spectroscopy

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sutter, P., E-mail: psutter@bnl.gov; Sutter, E.

    2014-09-01

    We assess scanning electron microscopy (SEM) and Auger electron spectroscopy (AES) for thickness measurements on few-layer hexagonal boron nitride (h-BN), the layered dielectric of choice for integration with graphene and other two-dimensional materials. Observations on h-BN islands with large, atomically flat terraces show that the secondary electron intensity in SEM reflects monolayer height changes in films up to least 10 atomic layers thickness. From a quantitative analysis of AES data, the energy-dependent electron escape depth in h-BN films is deduced. The results show that AES is suitable for absolute thickness measurements of few-layer h-BN of 1 to 6 layers.

  1. School Superintendents' Use of Electronic Communication Technology and Its Impact on Their Efficacy as a School District Leader

    ERIC Educational Resources Information Center

    Brock, Cecilia

    2017-01-01

    As apex leaders, school superintendents are impacted by the continuous demand to be effective while utilizing electronic communication technology. The purpose of this study is to investigate how the use of electronic communication technology impacts a school superintendent's efficacy. Public education, in the twenty-first century, finds itself in…

  2. Absolute irradiance of the Moon for on-orbit calibration

    USGS Publications Warehouse

    Stone, T.C.; Kieffer, H.H.; ,

    2002-01-01

    The recognized need for on-orbit calibration of remote sensing imaging instruments drives the ROLO project effort to characterize the Moon for use as an absolute radiance source. For over 5 years the ground-based ROLO telescopes have acquired spatially-resolved lunar images in 23 VNIR (Moon diameter ???500 pixels) and 9 SWIR (???250 pixels) passbands at phase angles within ??90 degrees. A numerical model for lunar irradiance has been developed which fits hundreds of ROLO images in each band, corrected for atmospheric extinction and calibrated to absolute radiance, then integrated to irradiance. The band-coupled extinction algorithm uses absorption spectra of several gases and aerosols derived from MODTRAN to fit time-dependent component abundances to nightly observations of standard stars. The absolute radiance scale is based upon independent telescopic measurements of the star Vega. The fitting process yields uncertainties in lunar relative irradiance over small ranges of phase angle and the full range of lunar libration well under 0.5%. A larger source of uncertainty enters in the absolute solar spectral irradiance, especially in the SWIR, where solar models disagree by up to 6%. Results of ROLO model direct comparisons to spacecraft observations demonstrate the ability of the technique to track sensor responsivity drifts to sub-percent precision. Intercomparisons among instruments provide key insights into both calibration issues and the absolute scale for lunar irradiance.

  3. High-resolution absolute position detection using a multiple grating

    NASA Astrophysics Data System (ADS)

    Schilling, Ulrich; Drabarek, Pawel; Kuehnle, Goetz; Tiziani, Hans J.

    1996-08-01

    To control electro-mechanical engines, high-resolution linear and rotary encoders are needed. Interferometric methods (grating interferometers) promise a resolution of a few nanometers, but have an ambiguity range of some microns. Incremental encoders increase the absolute measurement range by counting the signal periods starting from a defined initial point. In many applications, however, it is not possible to move to this initial point, so that absolute encoders have to be used. Absolute encoders generally have a scale with two or more tracks placed next to each other. Therefore, they use a two-dimensional grating structure to measure a one-dimensional position. We present a new method, which uses a one-dimensional structure to determine the position in one dimension. It is based on a grating with a large grating period up to some millimeters, having the same diffraction efficiency in several predefined diffraction orders (multiple grating). By combining the phase signals of the different diffraction orders, it is possible to establish the position in an absolute range of the grating period with a resolution like incremental grating interferometers. The principal functionality was demonstrated by applying the multiple grating in a heterodyne grating interferometer. The heterodyne frequency was generated by a frequency modulated laser in an unbalanced interferometer. In experimental measurements an absolute range of 8 mm was obtained while achieving a resolution of 10 nm.

  4. A rare gas optics-free absolute photon flux and energy analyzer for solar and planetary observations

    NASA Technical Reports Server (NTRS)

    Judge, Darrell L.

    1994-01-01

    We have developed a prototype spectrometer for space applications requiring long term absolute EUV photon flux measurements. In this recently developed spectrometer, the energy spectrum of the incoming photons is transformed directly into an electron energy spectrum by taking advantage of the photoelectric effect in one of several rare gases at low pressures. Using an electron energy spectrometer, followed by an electron multiplier detector, pulses due to individual electrons are counted. The overall efficiency of this process can be made essentially independent of gain drifts in the signal path, and the secular degradation of optical components which is often a problem in other techniques is avoided. A very important feature of this approach is its freedom from the problem of overlapping spectral orders that plagues grating EUV spectrometers. An instrument with these features has not been flown before, but is essential to further advances in our understanding of solar EUV flux dynamics, and the coupled dynamics of terrestrial and planetary atmospheres. The detailed characteristics of this optics-free spectrometer are presented in the publications section.

  5. Automatic solar image motion measurements. [electronic disk flux monitoring

    NASA Technical Reports Server (NTRS)

    Colgate, S. A.; Moore, E. P.

    1975-01-01

    The solar seeing image motion has been monitored electronically and absolutely with a 25 cm telescope at three sites along the ridge at the southern end of the Magdalena Mountains west of Socorro, New Mexico. The uncorrelated component of the variations of the optical flux from two points at opposite limbs of the solar disk was continually monitored in 3 frequencies centered at 0.3, 3 and 30 Hz. The frequency band of maximum signal centered at 3 Hz showed the average absolute value of image motion to be somewhat less than 2sec. The observer estimates of combined blurring and image motion were well correlated with electronically measured image motion, but the observer estimates gave a factor 2 larger value.

  6. Rate coefficients for dissociative attachment and resonant electron-impact dissociation involving vibrationally excited O{sub 2} molecules

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Laporta, V.; Celiberto, R.; Tennyson, J.

    Rate coefficients for dissociative electron attachment and electron-impact dissociation processes, involving vibrationally excited molecular oxygen, are presented. Analytical fits of the calculated numerical data, useful in the applications, are also provided.

  7. Electron impact ionization-excitation of Helium

    NASA Astrophysics Data System (ADS)

    Ancarani, Lorenzo Ugo; Gomez, A. I.; Gasaneo, G.; Mitnik, D. M.; Ambrosio, M. J.

    2016-09-01

    We calculate triple differential cross sections (TDCS) for the process of ionization-excitation of Helium by fast electron impact in which the residual ion is left in the n =2 excited state. We chose the strongly asymmetric kinematics used in the experiment performed by Dupré et al.. In a perturbative scheme, for high projectile energies the four-body problem reduces to a three-body one and, within that framework, we solve the time- independent Schrödinger equation with a Sturmian approach. The method, based on Generalized Sturmian Functions (GSF), is employed to obtain the initial ground state of Helium, the single-continuum state and the scattering wave function; for each of them, the GSF basis is constructed with the corresponding adequate asymptotic conditions. Besides, the method presents the following advantage: the scattering amplitudes can be extracted directly in the asymptotic region of the scattering solution, and thus the TDCS can be obtained without requiring a matrix element evaluation.

  8. A combined thermal dissociation and electron impact ionization source for RIB generation

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Alton, G.D.; Williams, C.

    1995-12-31

    The probability for simultaneously dissociating and efficiently ionizing the individual atomic constituents of molecular feed materials with conventional, hot-cathode, electron-impact ion sources is low and consequently, the ion beams from these sources often appear as mixtures of several molecular sideband beams. This fragmentation process leads to dilution of the intensity of the species of interest for RIB applications where beam intensity is at a premium. We have conceived an ion source that combines the excellent molecular dissociation properties of a thermal dissociator and the high ionization efficiency characteristics of an electron impact ionization source that will, in principle, overcome thismore » handicap. The source concept will be evaluated as a potential candidate for use for RIB generation at the Holifield Radioactive Ion Beam Facility (HRIBF), now under construction at the Oak Ridge National Laboratory. The design features and principles of operation of the source are described in this article.« less

  9. Absolute Distance Measurement with the MSTAR Sensor

    NASA Technical Reports Server (NTRS)

    Lay, Oliver P.; Dubovitsky, Serge; Peters, Robert; Burger, Johan; Ahn, Seh-Won; Steier, William H.; Fetterman, Harrold R.; Chang, Yian

    2003-01-01

    The MSTAR sensor (Modulation Sideband Technology for Absolute Ranging) is a new system for measuring absolute distance, capable of resolving the integer cycle ambiguity of standard interferometers, and making it possible to measure distance with sub-nanometer accuracy. The sensor uses a single laser in conjunction with fast phase modulators and low frequency detectors. We describe the design of the system - the principle of operation, the metrology source, beamlaunching optics, and signal processing - and show results for target distances up to 1 meter. We then demonstrate how the system can be scaled to kilometer-scale distances.

  10. Factors that impact nurses' use of electronic mail (e-mail).

    PubMed

    Hughes, J A; Pakieser, R A

    1999-01-01

    As electronic applications are used increasingly in healthcare, nurses are being challenged to adopt them. Electronic mail (e-mail) is an electronic tool with general as well as healthcare uses. E-mail use may be an opportunity to learn a tool that requires skills similar to those used in other applications. This study aimed to identify barriers and facilitators that impact nurses' use of e-mail in the workplace. Data for this study were gathered using focus group methodology. Content analysis identified and labeled factors into seven major categories. Specific factors identified were generally consistent with those previously described in the literature as affecting use of computers in general. However, there were several additional factors identified that were not reported in other previous studies: lack of face-to-face communication, individual writing skills, recency of any educational experience, volume of mail received, password integrity, and technical support. Findings from this study provide information for any individual involved in introducing or updating an e-mail system in a healthcare environment.

  11. Absolute and Relative Socioeconomic Health Inequalities across Age Groups

    PubMed Central

    van Zon, Sander K. R.; Bültmann, Ute; Mendes de Leon, Carlos F.; Reijneveld, Sijmen A.

    2015-01-01

    Background The magnitude of socioeconomic health inequalities differs across age groups. It is less clear whether socioeconomic health inequalities differ across age groups by other factors that are known to affect the relation between socioeconomic position and health, like the indicator of socioeconomic position, the health outcome, gender, and as to whether socioeconomic health inequalities are measured in absolute or in relative terms. The aim is to investigate whether absolute and relative socioeconomic health inequalities differ across age groups by indicator of socioeconomic position, health outcome and gender. Methods The study sample was derived from the baseline measurement of the LifeLines Cohort Study and consisted of 95,432 participants. Socioeconomic position was measured as educational level and household income. Physical and mental health were measured with the RAND-36. Age concerned eleven 5-years age groups. Absolute inequalities were examined by comparing means. Relative inequalities were examined by comparing Gini-coefficients. Analyses were performed for both health outcomes by both educational level and household income. Analyses were performed for all age groups, and stratified by gender. Results Absolute and relative socioeconomic health inequalities differed across age groups by indicator of socioeconomic position, health outcome, and gender. Absolute inequalities were most pronounced for mental health by household income. They were larger in younger than older age groups. Relative inequalities were most pronounced for physical health by educational level. Gini-coefficients were largest in young age groups and smallest in older age groups. Conclusions Absolute and relative socioeconomic health inequalities differed cross-sectionally across age groups by indicator of socioeconomic position, health outcome and gender. Researchers should critically consider the implications of choosing a specific age group, in addition to the indicator of

  12. Some things ought never be done: moral absolutes in clinical ethics.

    PubMed

    Pellegrino, Edmund D

    2005-01-01

    Moral absolutes have little or no moral standing in our morally diverse modern society. Moral relativism is far more palatable for most ethicists and to the public at large. Yet, when pressed, every moral relativist will finally admit that there are some things which ought never be done. It is the rarest of moral relativists that will take rape, murder, theft, child sacrifice as morally neutral choices. In general ethics, the list of those things that must never be done will vary from person to person. In clinical ethics, however, the nature of the physician-patient relationship is such that certain moral absolutes are essential to the attainment of the good of the patient - the end of the relationship itself. These are all derivatives of the first moral absolute of all morality: Do good and avoid evil. In the clinical encounter, this absolute entails several subsidiary absolutes - act for the good of the patient, do not kill, keep promises, protect the dignity of the patient, do not lie, avoid complicity with evil. Each absolute is intrinsic to the healing and helping ends of the clinical encounter.

  13. Absolute and relative educational inequalities in depression in Europe.

    PubMed

    Dudal, Pieter; Bracke, Piet

    2016-09-01

    To investigate (1) the size of absolute and relative educational inequalities in depression, (2) their variation between European countries, and (3) their relationship with underlying prevalence rates. Analyses are based on the European Social Survey, rounds three and six (N = 57,419). Depression is measured using the shortened Centre of Epidemiologic Studies Depression Scale. Education is coded by use of the International Standard Classification of Education. Country-specific logistic regressions are applied. Results point to an elevated risk of depressive symptoms among the lower educated. The cross-national patterns differ between absolute and relative measurements. For men, large relative inequalities are found for countries including Denmark and Sweden, but are accompanied by small absolute inequalities. For women, large relative and absolute inequalities are found in Belgium, Bulgaria, and Hungary. Results point to an empirical association between inequalities and the underlying prevalence rates. However, the strength of the association is only moderate. This research stresses the importance of including both measurements for comparative research and suggests the inclusion of the level of population health in research into inequalities in health.

  14. Relativistic Absolutism in Moral Education.

    ERIC Educational Resources Information Center

    Vogt, W. Paul

    1982-01-01

    Discusses Emile Durkheim's "Moral Education: A Study in the Theory and Application of the Sociology of Education," which holds that morally healthy societies may vary in culture and organization but must possess absolute rules of moral behavior. Compares this moral theory with current theory and practice of American educators. (MJL)

  15. Determining absolute protein numbers by quantitative fluorescence microscopy.

    PubMed

    Verdaasdonk, Jolien Suzanne; Lawrimore, Josh; Bloom, Kerry

    2014-01-01

    Biological questions are increasingly being addressed using a wide range of quantitative analytical tools to examine protein complex composition. Knowledge of the absolute number of proteins present provides insights into organization, function, and maintenance and is used in mathematical modeling of complex cellular dynamics. In this chapter, we outline and describe three microscopy-based methods for determining absolute protein numbers--fluorescence correlation spectroscopy, stepwise photobleaching, and ratiometric comparison of fluorescence intensity to known standards. In addition, we discuss the various fluorescently labeled proteins that have been used as standards for both stepwise photobleaching and ratiometric comparison analysis. A detailed procedure for determining absolute protein number by ratiometric comparison is outlined in the second half of this chapter. Counting proteins by quantitative microscopy is a relatively simple yet very powerful analytical tool that will increase our understanding of protein complex composition. © 2014 Elsevier Inc. All rights reserved.

  16. Secondary electron emission from lunar soil by solar wind type ion impact: Laboratory measurements

    NASA Astrophysics Data System (ADS)

    Dukes, Catherine; Bu, Caixia; Baragiola, Raul A.

    2015-11-01

    Introduction: The lunar surface potential is determined by time-varying fluxes of electrons and ions from the solar wind, photoelectrons ejected by UV photons, cosmic rays, and micrometeorite impacts. Solar wind ions have a dual role in the charging process, adding positive charge to the lunar regolith upon impact and ejecting negative secondary electrons (SE). Electron emission occurs when the energy from the impacting ion is transferred to the solid, ionizing and damaging the material; electrons with kinetic energy greater than the ionization potential (band gap + electron affinity) are ejected from the solid[1].Experiment: We investigate the energy distribution of secondary electrons ejected from Apollo soils of varying maturity and lunar analogs by 4 keV He+. Soils are placed into a shallow Al cup and compressed. In-situ low-energy oxygen plasma is used to clean atmospheric contaminants from the soil before analysis[2]. X-ray photoelectron spectroscopy ascertains that the sample surface is clean. Experiments are conducted in a PHI 560 system (<10-9 Torr), equipped with a double-pass, cylindrical-mirror electron energy analyzer (CMA) and μ-metal shield. The spectrometer is used to measure SE distributions, as well as for in situ surface characterization. A small negative bias (~5V) with respect to the grounded entrance grid of the CMA may be placed on the sample holder in order to expose the low energy cutoff.To measure SE energy distributions, primary ions rastered over a ~6 x 6 mm2 area are incident on the sample at ~40° relative to the surface normal, while SE emitted with an angle of 42.3°± 3.5° in a cone are analyzed.Results: The energy distribution of SE ejected from 4 keV He ion irradiation of albite with no bias applied shows positive charging of the surface. The general shape and distribution peak (~4 eV) are consistent with spectra for low energy ions on insulating material[1].Acknowledgements: We thank the NASA LASER program for support

  17. Absolute mass of neutrinos and the first unique forbidden {beta} decay of {sup 187}Re

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Dvornicky, Rastislav; Simkovic, Fedor; Bogoliubov Laboratory of Theoretical Physics, JINR Dubna, 141980 Dubna, Moscow region

    2011-04-15

    The planned rhenium {beta}-decay experiment, called the ''Microcalorimeter Arrays for a Rhenium Experiment'' (MARE), might probe the absolute mass scale of neutrinos with the same sensitivity as the Karlsruhe tritium neutrino mass (KATRIN) experiment, which will take commissioning data in 2011 and will proceed for 5 years. We present the energy distribution of emitted electrons for the first unique forbidden {beta} decay of {sup 187}Re. It is found that the p-wave emission of electron dominates over the s wave. By assuming mixing of three neutrinos, the Kurie function for the rhenium {beta} decay is derived. It is shown that themore » Kurie plot near the end point is within a good accuracy linear in the limit of massless neutrinos like the Kurie plot of the superallowed {beta} decay of {sup 3}H.« less

  18. Cross sections for the production of energetic cations by electron impact on N2 and CO2

    NASA Technical Reports Server (NTRS)

    Iga, I.; Srivastava, S. K.; Rao, M. V. V. S.; Katayama, D. H.

    1995-01-01

    Dissociative ionization cross sections for the production of singly charged energetic ions by electron impact on N2 and CO2 have been measured. The ions were divided into two groups: one with energies less than 1 eV and the other with energies greater than 1 eV. The ions detected were N+ from N2 and C+, O+, and CO+ from CO2. The electron impact energy range, and cross section data on ions is given.

  19. Electron impact excitation of the low-lying 3s[3/2]{sub 1} and 3s{sup ′}[1/2]{sub 1} levels in neon for incident energies between 20 and 300 eV

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Hoshino, M., E-mail: masami-h@sophia.ac.jp; Murai, H.; Kato, H.

    2013-11-14

    Absolute differential cross sections (DCSs) for electron impact of the two lower-lying 3s[3/2]{sub 1} ({sup 3}P{sub 0}) and 3s{sup ′}[1/2]{sub 1} ({sup 1}P{sub 1}) electronic states in neon (Ne) have been determined for eight incident electron energies in the range 20–300 eV. Comparisons between our results and previous measurements and calculations, where possible, are provided with best agreement being found with the recent large-scale B-spline R-matrix computations [O. Zatsarinny and K. Bartschat, Phys. Rev. A 86, 022717 (2012)]. Based on these DCSs at 100, 200, and 300 eV, a generalised oscillator strength analysis enabled us to determine estimates for themore » optical oscillator strengths of the 3s[3/2]{sub 1} and 3s{sup ′}[1/2]{sub 1} levels. In this case, excellent agreement was found with a range of independent experiments and calculations, giving us some confidence in the validity of our measurement and analysis procedures. Integral cross sections, derived from the present DCSs, were presented graphically and discussed elsewhere [M. Hoshino, H. Murai, H. Kato, Y. Itikawa, M. J. Brunger, and H. Tanaka, Chem. Phys. Lett. 585, 33 (2013)], but are tabulated here for completeness.« less

  20. Establishing Ion Ratio Thresholds Based on Absolute Peak Area for Absolute Protein Quantification using Protein Cleavage Isotope Dilution Mass Spectrometry

    PubMed Central

    Loziuk, Philip L.; Sederoff, Ronald R.; Chiang, Vincent L.; Muddiman, David C.

    2014-01-01

    Quantitative mass spectrometry has become central to the field of proteomics and metabolomics. Selected reaction monitoring is a widely used method for the absolute quantification of proteins and metabolites. This method renders high specificity using several product ions measured simultaneously. With growing interest in quantification of molecular species in complex biological samples, confident identification and quantitation has been of particular concern. A method to confirm purity or contamination of product ion spectra has become necessary for achieving accurate and precise quantification. Ion abundance ratio assessments were introduced to alleviate some of these issues. Ion abundance ratios are based on the consistent relative abundance (RA) of specific product ions with respect to the total abundance of all product ions. To date, no standardized method of implementing ion abundance ratios has been established. Thresholds by which product ion contamination is confirmed vary widely and are often arbitrary. This study sought to establish criteria by which the relative abundance of product ions can be evaluated in an absolute quantification experiment. These findings suggest that evaluation of the absolute ion abundance for any given transition is necessary in order to effectively implement RA thresholds. Overall, the variation of the RA value was observed to be relatively constant beyond an absolute threshold ion abundance. Finally, these RA values were observed to fluctuate significantly over a 3 year period, suggesting that these values should be assessed as close as possible to the time at which data is collected for quantification. PMID:25154770

  1. The impact of electron beam irradiation on Low density polyethylene and Ethylene vinyl acetate

    NASA Astrophysics Data System (ADS)

    Sabet, Maziyar; Soleimani, Hassan

    2017-05-01

    Improvement of measured gel content, hardness, tensile strength and elongation at break of Ethylene vinyl acetate (EVA) have confirmed positive effect of electron beam irradiation on EVA. Results obtained from both gel content tests show that degree of cross-linking in amorphous regions is dependent on dose. A significant improvement in tensile strength of neat EVA samples is obtained upon electron-beam radiation up to 210 kGy. Similarly, hardness properties of Low-density polyethylene (LDPE) improvewith increasing electron beam irradiation. This article deals with the impacts of electron beam (EB) irradiation on the properties of LDPE and Ethylene-Vinyl Acetate (EVA) as the two common based formulations for wire and cable applications.

  2. 0.2 to 10 keV electrons interacting with water ice: Radiolysis, sputtering, and sublimation

    NASA Astrophysics Data System (ADS)

    Galli, A.; Vorburger, A.; Wurz, P.; Pommerol, A.; Cerubini, R.; Jost, B.; Poch, O.; Tulej, M.; Thomas, N.

    2018-06-01

    We present new laboratory experiments investigating various water ice samples, ranging from thin ice films to porous thick ice layers, that are irradiated with electrons. The molecules leaving the ice are monitored with a pressure gauge and a mass spectrometer. Most particles released from the ice are H2 and O2, the observed ratio of 2:1 is consistent with H2O being radiolysed into H2 + 1/2 O2 upon irradiation. H2O2 is likely a minor contribution of radiolysis, amounting to 0.001 ± 0.001 of the total gas release from the ice sample. Neither the physical properties of the ice, nor the energy, nor the electron impact angle have any obvious effect on the relative abundances of the radiolysis products. The absolute sputtering yield (i.e., the ratio of produced O2 or destroyed H2O per impacting electron) increases with energy until a few 100 eV. For higher energies up to 10 keV the yield remains roughly constant, once the saturation dose of the ice is reached. This indicates that ongoing irradiation eventually releases the radiolysis products from the water ice even for penetration depths of several micrometers.

  3. A Single Chiroptical Spectroscopic Method May Not Be Able To Establish the Absolute Configurations of Diastereomers: Dimethylesters of Hibiscus and Garcinia Acids

    PubMed Central

    Polavarapu, Prasad L.; Donahue, Emily A.; Shanmugam, Ganesh; Scalmani, Giovanni; Hawkins, Edward K.; Rizzo, Carmelo; Ibnusaud, Ibrahim; Thomas, Grace; Habel, Deenamma; Sebastian, Dellamol

    2013-01-01

    Electronic circular dichroism (ECD), optical rotatory dispersion (ORD), and vibrational circular dichroism (VCD) spectra of hibiscus acid dimethyl ester have been measured and analyzed in combination with quantum chemical calculations of corresponding spectra. These results, along with those reported previously for garcinia acid dimethyl ester, reveal that none of these three (ECD, ORD, or VCD) spectroscopic methods, in isolation, can unequivocally establish the absolute configurations of diastereomers. This deficiency is eliminated when a combined spectral analysis of either ECD and VCD or ORD and VCD methods is used. It is also found that the ambiguities in the assignment of absolute configurations of diastereomers may also be overcome when unpolarized vibrational absorption is included in the spectral analysis. PMID:21568330

  4. The Pervasiveness and Impact of Electronic Communication Technologies in Organizations: A Survey of Major American Corporations.

    ERIC Educational Resources Information Center

    Hellweg, Susan A.; And Others

    A survey of the Fortune 500 corporations was conducted to ascertain the pervasiveness and perceived impact of five electronic communication technologies (electronic mail, videotex, interactive computers, video teleconferencing, and word processing). Ninety-four corporations responded to a 53-item questionnaire and follow-up survey. Analysis of the…

  5. Essential Oils, Part VI: Sandalwood Oil, Ylang-Ylang Oil, and Jasmine Absolute.

    PubMed

    de Groot, Anton C; Schmidt, Erich

    In this article, some aspects of sandalwood oil, ylang-ylang oil, and jasmine absolute are discussed including their botanical origin, uses of the plants and the oils and absolute, chemical composition, contact allergy to and allergic contact dermatitis from these essential oils and absolute, and their causative allergenic ingredients.

  6. The electronic, 'paperless' medical office; has it arrived?

    PubMed

    Gates, P; Urquhart, J

    2007-02-01

    Modern information technology offers efficiencies in medical practice, with a reduction in secretarial time in maintaining, filing and retrieving the paper medical record. Electronic requesting of investigations allows tracking of outstanding results. Less storage space is required and telephone calls from pharmacies, pathology and medical imaging service providers to clarify the hand-written request are abolished. Voice recognition software reduces secretarial typing time per letter. These combined benefits can lead to significantly reduced costs and improved patient care. The paperless office is possible, but requires commitment and training of all staff; it is preferable but not absolutely essential that at least one member of the practice has an interest and some expertise in computers. More importantly, back-up from information technology providers and back-up of the electronic data are absolutely crucial and a paperless environment should not be considered without them.

  7. Temporal Dynamics of Microbial Rhodopsin Fluorescence Reports Absolute Membrane Voltage

    PubMed Central

    Hou, Jennifer H.; Venkatachalam, Veena; Cohen, Adam E.

    2014-01-01

    Plasma membrane voltage is a fundamentally important property of a living cell; its value is tightly coupled to membrane transport, the dynamics of transmembrane proteins, and to intercellular communication. Accurate measurement of the membrane voltage could elucidate subtle changes in cellular physiology, but existing genetically encoded fluorescent voltage reporters are better at reporting relative changes than absolute numbers. We developed an Archaerhodopsin-based fluorescent voltage sensor whose time-domain response to a stepwise change in illumination encodes the absolute membrane voltage. We validated this sensor in human embryonic kidney cells. Measurements were robust to variation in imaging parameters and in gene expression levels, and reported voltage with an absolute accuracy of 10 mV. With further improvements in membrane trafficking and signal amplitude, time-domain encoding of absolute voltage could be applied to investigate many important and previously intractable bioelectric phenomena. PMID:24507604

  8. 242Pu absolute neutron-capture cross section measurement

    NASA Astrophysics Data System (ADS)

    Buckner, M. Q.; Wu, C. Y.; Henderson, R. A.; Bucher, B.; Chyzh, A.; Bredeweg, T. A.; Baramsai, B.; Couture, A.; Jandel, M.; Mosby, S.; O'Donnell, J. M.; Ullmann, J. L.

    2017-09-01

    The absolute neutron-capture cross section of 242Pu was measured at the Los Alamos Neutron Science Center using the Detector for Advanced Neutron-Capture Experiments array along with a compact parallel-plate avalanche counter for fission-fragment detection. During target fabrication, a small amount of 239Pu was added to the active target so that the absolute scale of the 242Pu(n,γ) cross section could be set according to the known 239Pu(n,f) resonance at En,R = 7.83 eV. The relative scale of the 242Pu(n,γ) cross section covers four orders of magnitude for incident neutron energies from thermal to ≈ 40 keV. The cross section reported in ENDF/B-VII.1 for the 242Pu(n,γ) En,R = 2.68 eV resonance was found to be 2.4% lower than the new absolute 242Pu(n,γ) cross section.

  9. Temperature dependence of electron impact ionization coefficient in bulk silicon

    NASA Astrophysics Data System (ADS)

    Ahmed, Mowfaq Jalil

    2017-09-01

    This work exhibits a modified procedure to compute the electron impact ionization coefficient of silicon for temperatures between 77 and 800K and electric fields ranging from 70 to 400 kV/cm. The ionization coefficients are computed from the electron momentum distribution function through solving the Boltzmann transport equation (BTE). The arrangement is acquired by joining Legendre polynomial extension with BTE. The resulting BTE is solved by differences-differential method using MATLAB®. Six (X) equivalent ellipsoidal and non-parabolic valleys of the conduction band of silicon are taken into account. Concerning the scattering mechanisms, the interval acoustic scattering, non-polar optical scattering and II scattering are taken into consideration. This investigation showed that the ionization coefficients decrease with increasing temperature. The overall results are in good agreement with previous experimental and theoretical reported data predominantly at high electric fields.

  10. Relativistic atomic structure calculations and electron impact excitations of Fe23+

    NASA Astrophysics Data System (ADS)

    El-Maaref, A. A.

    2016-02-01

    Relativistic calculations using the multiconfiguration Dirac-Fock method for energy levels, oscillator strengths, and electronic dipole transition probabilities of Li-like iron (Fe23+) are presented. A configuration state list with the quantum numbers nl, where n = 2 - 7 and l = s , p , d , f , g , h , i has been considered. Excitations up to three electrons and correlation contributions from higher orbitals up to 7 l have been included. Contributions from core levels have been taken into account, EOL (extended optimal level) type calculations have been applied, and doubly excited levels are considered. The calculations have been executed by using the fully relativistic atomic structure package GRASP2K. The present calculations have been compared with the available experimental and theoretical sources, the comparisons show a good agreement between the present results of energy levels and oscillator strengths with the literature. In the second part of the present study, the atomic data (energy levels, and radiative parameters) have been used to calculate the excitation and deexcitation rates of allowed transitions by electron impact, as well as the population densities of some excited levels at different electron temperatures.

  11. A Survey of Electron Impact Cross-Sections for Halogens and Halogen Compounds of Interest to Plasma Processing

    NASA Technical Reports Server (NTRS)

    Sharma, S. P.; Rao, M. V. V. S.; Arnold, James O. (Technical Monitor)

    1998-01-01

    Published electron impact cross section data on halogens Cl2, F2, and halogen containing compounds such as Cx Fy, HCl, Cx Cly Fz are reviewed and critically evaluated based on the information provided by various researchers. The present work reports data on electron impact excitation, ionization, dissociation, electron attachment, electron detachment, and photo detachment. Elastic scattering cross sections and data on bulk properties such as diffusion coefficients in various background gases are also evaluated. Since some of the cross sectional data is derived from indirect measurements such as drift velocity, care has been taken to reconcile the differences among the reported data with due attention to the measurement technique. In conclusion, the processes with no or very limited amount of data and questionable set of data are identified and recommendation for further research direction is made.

  12. The kinetic energy spectrum of protons produced by the dissociative ionization of H2 by electron impact

    NASA Technical Reports Server (NTRS)

    Khakoo, M. A.; Srivastava, S. K.

    1985-01-01

    The kinetic energy spectra of protons resulting from the dissociative ionization of H2 by electron impact have been measured for electron impact energies from threshold (approximately 17 eV) to 160 eV at 90 deg and 30 deg detection angles, using a crossed-beam experimental arrangement. To check reliability, two separate proton energy analysis methods have been employed, i.e., a time-of-flight proton energy analysis and an electrostatic hemispherical energy analyzer. The present results are compared with previous measurements.

  13. The Impact of an Integrated Electronic Health Record Adoption on Nursing Care Quality.

    PubMed

    Walker-Czyz, AnneMarie

    2016-01-01

    The purpose of this study was to measure the impact of an integrated electronic health record (EHR) innovation adoption on the quality of nursing care delivered, including hospital-acquired falls, hospital-acquired pressure ulcers, ventilator-associated pneumonia (VAP), central line-associated bloodstream infections (CLABSIs), catheter-associated urinary tract infections (CAUTIs), and costs measured in nursing hours. The impact on quality, cost, and nurse satisfaction measured in turnover rates before, during, and after implementation of EHR tools was also investigated. Little is known about the adoption patterns of computerized documentation by nursing and the effects on the practice environment. A quantitative, retrospective analysis using interrupted time series model of a large data set was conducted in a 431-bed urban hospital, with 10 medical surgical units and 2 critical care units. The research was constructed using the Diffusion of Innovations (DOI) theory. Incorporating electronic, evidenced-based practice (EBP) tools into bedside nurse's workflow promotes decision making at the point of care that may improve quality with no negative impact on direct cost. The data revealed that total falls, CAUTI, and CLABSI rates were positively impacted after the implementation of an integrated EHR. Hospital-acquired pressure ulcer and VAP rates were negatively impacted at the implementation period followed by a significant positive rate reduction that surpassed the preimplementation period. Cost indicators, measured in hours per patient day and overtime, were negatively impacted during the implementation period followed by a return to baseline. Nurse turnover had a significant increase from the preimplementation to postimplementation period and failed to return to baseline. This study confirms that nurses have the ability to positively impact the quality of patient care through successful innovation adoption related to the use of EBP computerized documentation tools

  14. Electron- and photon-impact ionization of furfural

    NASA Astrophysics Data System (ADS)

    Jones, D. B.; Ali, E.; Nixon, K. L.; Limão-Vieira, P.; Hubin-Franskin, M.-J.; Delwiche, J.; Ning, C. G.; Colgan, J.; Murray, A. J.; Madison, D. H.; Brunger, M. J.

    2015-11-01

    The He(i) photoelectron spectrum of furfural has been investigated, with its vibrational structure assigned for the first time. The ground and excited ionized states are assigned through ab initio calculations performed at the outer-valence Green's function level. Triple differential cross sections (TDCSs) for electron-impact ionization of the unresolved combination of the 4a″ + 21a' highest and next-highest occupied molecular orbitals have also been obtained. Experimental TDCSs are recorded in a combination of asymmetric coplanar and doubly symmetric coplanar kinematics. The experimental TDCSs are compared to theoretical calculations, obtained within a molecular 3-body distorted wave framework that employed either an orientation average or proper TDCS average. The proper average calculations suggest that they may resolve some of the discrepancies regarding the angular distributions of the TDCS, when compared to calculations employing the orbital average.

  15. Axial interaction free-electron laser

    DOEpatents

    Carlsten, Bruce E.

    1997-01-01

    Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies.

  16. Axial interaction free-electron laser

    DOEpatents

    Carlsten, B.E.

    1997-09-02

    Electron orbits from a helical axial wiggler in an axial guide field are absolutely unstable as power is extracted from the particles. For off-axis beams an axial FEL mechanism exists when the axial electric field in a TM mode is wiggled to interact with the axial velocity of the electrons that form the beam. The interaction strength is comparable to that for helical FELs and is insensitive to beam orbit errors. The orbits for this mechanism are extremely stable in the absence of space charge and lead to high extraction efficiencies without particle phasing incoherence or interception. This interaction mechanism is suitable for use with intense annular electron beams for high power generation at microwave frequencies. 5 figs.

  17. Sequence dependence of electron-induced DNA strand breakage revealed by DNA nanoarrays

    PubMed Central

    Keller, Adrian; Rackwitz, Jenny; Cauët, Emilie; Liévin, Jacques; Körzdörfer, Thomas; Rotaru, Alexandru; Gothelf, Kurt V.; Besenbacher, Flemming; Bald, Ilko

    2014-01-01

    The electronic structure of DNA is determined by its nucleotide sequence, which is for instance exploited in molecular electronics. Here we demonstrate that also the DNA strand breakage induced by low-energy electrons (18 eV) depends on the nucleotide sequence. To determine the absolute cross sections for electron induced single strand breaks in specific 13 mer oligonucleotides we used atomic force microscopy analysis of DNA origami based DNA nanoarrays. We investigated the DNA sequences 5′-TT(XYX)3TT with X = A, G, C and Y = T, BrU 5-bromouracil and found absolute strand break cross sections between 2.66 · 10−14 cm2 and 7.06 · 10−14 cm2. The highest cross section was found for 5′-TT(ATA)3TT and 5′-TT(ABrUA)3TT, respectively. BrU is a radiosensitizer, which was discussed to be used in cancer radiation therapy. The replacement of T by BrU into the investigated DNA sequences leads to a slight increase of the absolute strand break cross sections resulting in sequence-dependent enhancement factors between 1.14 and 1.66. Nevertheless, the variation of strand break cross sections due to the specific nucleotide sequence is considerably higher. Thus, the present results suggest the development of targeted radiosensitizers for cancer radiation therapy. PMID:25487346

  18. Confidence-Accuracy Calibration in Absolute and Relative Face Recognition Judgments

    ERIC Educational Resources Information Center

    Weber, Nathan; Brewer, Neil

    2004-01-01

    Confidence-accuracy (CA) calibration was examined for absolute and relative face recognition judgments as well as for recognition judgments from groups of stimuli presented simultaneously or sequentially (i.e., simultaneous or sequential mini-lineups). When the effect of difficulty was controlled, absolute and relative judgments produced…

  19. Reliable absolute analog code retrieval approach for 3D measurement

    NASA Astrophysics Data System (ADS)

    Yu, Shuang; Zhang, Jing; Yu, Xiaoyang; Sun, Xiaoming; Wu, Haibin; Chen, Deyun

    2017-11-01

    The wrapped phase of phase-shifting approach can be unwrapped by using Gray code, but both the wrapped phase error and Gray code decoding error can result in period jump error, which will lead to gross measurement error. Therefore, this paper presents a reliable absolute analog code retrieval approach. The combination of unequal-period Gray code and phase shifting patterns at high frequencies are used to obtain high-frequency absolute analog code, and at low frequencies, the same unequal-period combination patterns are used to obtain the low-frequency absolute analog code. Next, the difference between the two absolute analog codes was employed to eliminate period jump errors, and a reliable unwrapped result can be obtained. Error analysis was used to determine the applicable conditions, and this approach was verified through theoretical analysis. The proposed approach was further verified experimentally. Theoretical analysis and experimental results demonstrate that the proposed approach can perform reliable analog code unwrapping.

  20. Absolute or relative? A comparative analysis of the relationship between poverty and mortality.

    PubMed

    Fritzell, Johan; Rehnberg, Johan; Bacchus Hertzman, Jennie; Blomgren, Jenni

    2015-01-01

    We aimed to examine the cross-national and cross-temporal association between poverty and mortality, in particular differentiating the impact of absolute and relative poverty. We employed pooled cross-sectional time series analysis. Our measure of relative poverty was based upon the standard 60% of median income. The measure of absolute, or fixed, poverty was based upon the US poverty threshold. Our analyses were conducted on data for 30 countries between 1978 and 2010, a total of 149 data points. We separately studied infant, child, and adult mortality. Our findings highlight the importance of relative poverty for mortality. Especially for infant and child mortality, we found that our estimates of fixed poverty is close to zero either in the crude models, or when adjusting for gross domestic product. Conversely, the relative poverty estimates increased when adjusting for confounders. Our results seemed robust to a number of sensitivity tests. If we agree that risk of death is important, the public policy implication of our findings is that relative poverty, which has close associations to overall inequality, should be a major concern also among rich countries.

  1. Impact excitation and electron-hole multiplication in graphene and carbon nanotubes.

    PubMed

    Gabor, Nathaniel M

    2013-06-18

    In semiconductor photovoltaics, photoconversion efficiency is governed by a simple competition: the incident photon energy is either transferred to the crystal lattice (heat) or transferred to electrons. In conventional materials, energy loss to the lattice is more efficient than energy transferred to electrons, thus limiting the power conversion efficiency. Quantum electronic systems, such as quantum dots, nanowires, and two-dimensional electronic membranes, promise to tip the balance in this competition by simultaneously limiting energy transfer to the lattice and enhancing energy transfer to electrons. By exploring the optical, thermal, and electronic properties of quantum materials, we may perhaps find an ideal optoelectronic material that provides low cost fabrication, facile systems integration, and a means to surpass the standard limit for photoconversion efficiency. Nanoscale carbon materials, such as graphene and carbon nanotubes, provide ideal experimental quantum systems in which to explore optoelectronic behavior for applications in solar energy harvesting. Within essentially the same material, researchers can achieve a broad spectrum of energetic configurations, from a gapless semimetal to a large band-gap semiconducting nanowire. Owing to their nanoscale dimensions, graphene and carbon nanotubes exhibit electronic and optical properties that reflect strong electron-electron interactions. Such strong interactions may lead to exotic low-energy electron transport behavior and high-energy electron scattering processes such as impact excitation and the inverse process of Auger recombination. High-energy processes, which become very important under photoexcitation, may be particularly efficient in nanoscale carbon materials due to the relativistic-like, charged particle band structure and sensitivity to the dielectric environment. In addition, due to the covalently bonded carbon framework that makes up these materials, electron-phonon coupling is very weak

  2. Auditory working memory predicts individual differences in absolute pitch learning.

    PubMed

    Van Hedger, Stephen C; Heald, Shannon L M; Koch, Rachelle; Nusbaum, Howard C

    2015-07-01

    Absolute pitch (AP) is typically defined as the ability to label an isolated tone as a musical note in the absence of a reference tone. At first glance the acquisition of AP note categories seems like a perceptual learning task, since individuals must assign a category label to a stimulus based on a single perceptual dimension (pitch) while ignoring other perceptual dimensions (e.g., loudness, octave, instrument). AP, however, is rarely discussed in terms of domain-general perceptual learning mechanisms. This is because AP is typically assumed to depend on a critical period of development, in which early exposure to pitches and musical labels is thought to be necessary for the development of AP precluding the possibility of adult acquisition of AP. Despite this view of AP, several previous studies have found evidence that absolute pitch category learning is, to an extent, trainable in a post-critical period adult population, even if the performance typically achieved by this population is below the performance of a "true" AP possessor. The current studies attempt to understand the individual differences in learning to categorize notes using absolute pitch cues by testing a specific prediction regarding cognitive capacity related to categorization - to what extent does an individual's general auditory working memory capacity (WMC) predict the success of absolute pitch category acquisition. Since WMC has been shown to predict performance on a wide variety of other perceptual and category learning tasks, we predict that individuals with higher WMC should be better at learning absolute pitch note categories than individuals with lower WMC. Across two studies, we demonstrate that auditory WMC predicts the efficacy of learning absolute pitch note categories. These results suggest that a higher general auditory WMC might underlie the formation of absolute pitch categories for post-critical period adults. Implications for understanding the mechanisms that underlie the

  3. Calculation of ground state rotational populations for kinetic gas homonuclear diatomic molecules including electron-impact excitation and wall collisions.

    PubMed

    Farley, David R

    2010-09-07

    A model has been developed to calculate the ground state rotational populations of homonuclear diatomic molecules in kinetic gases, including the effects of electron-impact excitation, wall collisions, and gas feed rate. The equations are exact within the accuracy of the cross sections used and of the assumed equilibrating effect of wall collisions. It is found that the inflow of feed gas and equilibrating wall collisions can significantly affect the rotational distribution in competition with nonequilibrating electron-impact effects. The resulting steady-state rotational distributions are generally Boltzmann for N≥3, with a rotational temperature between the wall and feed gas temperatures. The N=0,1,2 rotational level populations depend sensitively on the relative rates of electron-impact excitation versus wall collision and gas feed rates.

  4. Using electronic patient records to inform strategic decision making in primary care.

    PubMed

    Mitchell, Elizabeth; Sullivan, Frank; Watt, Graham; Grimshaw, Jeremy M; Donnan, Peter T

    2004-01-01

    Although absolute risk of death associated with raised blood pressure increases with age, the benefits of treatment are greater in elderly patients. Despite this, the 'rule of halves' particularly applies to this group. We conducted a randomised controlled trial to evaluate different levels of feedback designed to improve identification, treatment and control of elderly hypertensives. Fifty-two general practices were randomly allocated to either: Control (n=19), Audit only feedback (n=16) or Audit plus Strategic feedback, prioritising patients by absolute risk (n=17). Feedback was based on electronic data, annually extracted from practice computer systems. Data were collected for 265,572 patients, 30,345 aged 65-79. The proportion of known hypertensives in each group with BP recorded increased over the study period and the numbers of untreated and uncontrolled patients reduced. There was a significant difference in mean systolic pressure between the Audit plus Strategic and Audit only groups and significantly greater control in the Audit plus Strategic group. Providing patient-specific practice feedback can impact on identification and management of hypertension in the elderly and produce a significant increase in control.

  5. Bite-outs and other depletions of mesospheric electrons

    PubMed Central

    Friedrich, Martin; Rapp, Markus; Plane, John M.C.; Torkar, Klaus M.

    2011-01-01

    The ionised mesosphere is less understood than other parts of the ionosphere because of the challenges of making appropriate measurements in this complex region. We use rocket borne in situ measurements of absolute electron density by the Faraday rotation technique and accompanying DC-probe measurements to study the effect of particles on the D-region charge balance. Several examples of electron bite-outs, their actual depth as well as simultaneous observations of positive ions are presented. For a better understanding of the various dependencies we use the ratio β/αi (attachment rate over ion–ion recombination coefficient), derived from the electron and ion density profiles by applying a simplified ion-chemical scheme, and correlate this term with solar zenith angle and moon brightness. The probable causes are different for day and night; recent in situ measurements support existing hypotheses for daytime cases, but also reveal behaviour at night hitherto not reported in the literature. Within the large range of β/αi values obtained from the analysis of 28 high latitude night flights one finds that the intensity of scattered sunlight after sunset, and even moonlight, apparently can photodetach electrons from meteoric smoke particles (MSP) and molecular anions. The large range of values itself can best be explained by the variability of the MSPs and by occasionally occurring atomic oxygen impacting on the negative ion chemistry in the night-time mesosphere under disturbed conditions. PMID:27570472

  6. Method and apparatus for two-dimensional absolute optical encoding

    NASA Technical Reports Server (NTRS)

    Leviton, Douglas B. (Inventor)

    2004-01-01

    This invention presents a two-dimensional absolute optical encoder and a method for determining position of an object in accordance with information from the encoder. The encoder of the present invention comprises a scale having a pattern being predetermined to indicate an absolute location on the scale, means for illuminating the scale, means for forming an image of the pattern; and detector means for outputting signals derived from the portion of the image of the pattern which lies within a field of view of the detector means, the field of view defining an image reference coordinate system, and analyzing means, receiving the signals from the detector means, for determining the absolute location of the object. There are two types of scale patterns presented in this invention: grid type and starfield type.

  7. Hydrogen rearrangements in the fragmentation of anthracene by low-energy electron impact

    NASA Astrophysics Data System (ADS)

    van der Burgt, Peter J. M.; Dunne, Melissa; Gradziel, Marcin L.

    2018-02-01

    We have measured mass spectra for positive ions produced by low-energy electron impact on anthracene using a reflectron time-of-flight mass spectrometer. The electron impact energy has been varied from 0 to 100 eV in steps of 0.5 eV. Ion yield curves of most of the fragment ions have been determined by fitting groups of adjacent peaks in the mass spectra with sequences of normalized Gaussians. Appearance energies for all these ions have been determined, and we report the first direct measurement of the triple ionization energy of anthracene at 45.5±0.5 eV. The groups of fragments containing 8-13 carbon atoms provide evidence for hydrogen rearrangements during the fragmentation, involving retention or loss of one or two additional hydrogen atoms. Groups of fragments with 6 and 7 carbon atoms clearly show the presence of doubly-charged fragments. The smaller fragments with 1-4 carbon atoms all show broadened peaks, and these fragments may be partly or mostly due to energetic charge-separation fragmentations of doubly-charged anthracene.

  8. New design and facilities for the International Database for Absolute Gravity Measurements (AGrav): A support for the Establishment of a new Global Absolute Gravity Reference System

    NASA Astrophysics Data System (ADS)

    Wziontek, Hartmut; Falk, Reinhard; Bonvalot, Sylvain; Rülke, Axel

    2017-04-01

    After about 10 years of successful joint operation by BGI and BKG, the International Database for Absolute Gravity Measurements "AGrav" (see references hereafter) was under a major revision. The outdated web interface was replaced by a responsive, high level web application framework based on Python and built on top of Pyramid. Functionality was added, like interactive time series plots or a report generator and the interactive map-based station overview was updated completely, comprising now clustering and the classification of stations. Furthermore, the database backend was migrated to PostgreSQL for better support of the application framework and long-term availability. As comparisons of absolute gravimeters (AG) become essential to realize a precise and uniform gravity standard, the database was extended to document the results on international and regional level, including those performed at monitoring stations equipped with SGs. By this it will be possible to link different AGs and to trace their equivalence back to the key comparisons under the auspices of International Committee for Weights and Measures (CIPM) as the best metrological realization of the absolute gravity standard. In this way the new AGrav database accommodates the demands of the new Global Absolute Gravity Reference System as recommended by the IAG Resolution No. 2 adopted in Prague 2015. The new database will be presented with focus on the new user interface and new functionality, calling all institutions involved in absolute gravimetry to participate and contribute with their information to built up a most complete picture of high precision absolute gravimetry and improve its visibility. A Digital Object Identifier (DOI) will be provided by BGI to contributors to give a better traceability and facilitate the referencing of their gravity surveys. Links and references: BGI mirror site : http://bgi.obs-mip.fr/data-products/Gravity-Databases/Absolute-Gravity-data/ BKG mirror site: http

  9. Influence of electron correlation on the cross section and linear polarization of radiation emitted by electron-impact excitation of Ca+ and Ba+ ions

    NASA Astrophysics Data System (ADS)

    Chen, Zhan-Bin

    2018-04-01

    Calculations of the electron-impact excitation (EIE) of singly charged Ca+ and Ba+ ions and subsequent de-excitation process are performed using a fully relativistic distorted wave (RDW) method. To resolve the discrepancy between previous theory and experiment, careful consideration is given to the generation of the target state wave-functions through the systematic inclusion of electron correlations. It is found that the electron correlation effects play a significant role on the cross section, while the effects on the linear polarization of the emitted radiation are relatively small. Good agreement between our result and experiment is obtained.

  10. Electron impact excitation of molecular hydrogen

    DOE PAGES

    Zammit, Mark Christian; Savage, Jeremy S.; Fursa, Dmitry V.; ...

    2017-02-06

    Here, we report the electron impact integrated and differential cross sections for excitation to the b 3Σmore » $$+\\atop{u}$$, a 3Σ$$+\\atop{g}$$, c 3Π u, B 1Σ$$+\\atop{u}$$, E, F 1Σ$$+\\atop{g}$$, C 1Π u, e 3Σ$$+\\atop{u}$$, h 3Σ $$+\\atop{g}$$, d 3Π u, B'' 1Σ$$+\\atop{u}$$ , D 1Π u, B'' 1Σ$$+\\atop{u}$$, and D' 1Π u states of molecular hydrogen in the energy range from 10 to 300 eV. Total scattering and total ionization cross sections are also presented. The calculations have been performed by using the convergent close-coupling method within the fixed-nuclei approximation. Detailed convergence studies have been performed with respect to the size of the close-coupling expansion and a set of recommended cross sections has been produced. Significant differences with previous calculations are found. Agreement with experiment is mixed, ranging from excellent to poor depending on the transition and incident energies.« less

  11. Fast Simulation of the Impact Parameter Calculation of Electrons through Pair Production

    NASA Astrophysics Data System (ADS)

    Bang, Hyesun; Kweon, MinJung; Huh, Kyoung Bum; Pachmayer, Yvonne

    2018-05-01

    A fast simulation method is introduced that reduces tremendously the time required for the impact parameter calculation, a key observable in physics analyses of high energy physics experiments and detector optimisation studies. The impact parameter of electrons produced through pair production was calculated considering key related processes using the Bethe-Heitler formula, the Tsai formula and a simple geometric model. The calculations were performed at various conditions and the results were compared with those from full GEANT4 simulations. The computation time using this fast simulation method is 104 times shorter than that of the full GEANT4 simulation.

  12. 237Np absolute delayed neutron yield measurements

    NASA Astrophysics Data System (ADS)

    Doré, D.; Ledoux, X.; Nolte, R.; Gagnon-Moisan, F.; Thulliez, L.; Litaize, O.; Roettger, S.; Serot, O.

    2017-09-01

    237Np absolute delayed neutron yields have been measured at different incident neutron energies from 1.5 to 16 MeV. The experiment was performed at the Physikalisch-Technische Bundesanstalt (PTB) facility where the Van de Graaff accelerator and the cyclotron CV28 delivered 9 different neutron energy beams using p+T, d+D and d+T reactions. The detection system is made up of twelve 3He tubes inserted into a polyethylene cylinder. In this paper, the experimental setup and the data analysis method are described. The evolution of the absolute DN yields as a function of the neutron incident beam energies are presented and compared to experimental data found in the literature and data from the libraries.

  13. An absolute measure for a key currency

    NASA Astrophysics Data System (ADS)

    Oya, Shunsuke; Aihara, Kazuyuki; Hirata, Yoshito

    It is generally considered that the US dollar and the euro are the key currencies in the world and in Europe, respectively. However, there is no absolute general measure for a key currency. Here, we investigate the 24-hour periodicity of foreign exchange markets using a recurrence plot, and define an absolute measure for a key currency based on the strength of the periodicity. Moreover, we analyze the time evolution of this measure. The results show that the credibility of the US dollar has not decreased significantly since the Lehman shock, when the Lehman Brothers bankrupted and influenced the economic markets, and has increased even relatively better than that of the euro and that of the Japanese yen.

  14. The Dependence of Cloud Property Trend Detection on Absolute Calibration Accuracy of Passive Satellite Sensors

    NASA Astrophysics Data System (ADS)

    Shea, Y.; Wielicki, B. A.; Sun-Mack, S.; Minnis, P.; Zelinka, M. D.

    2016-12-01

    Detecting trends in climate variables on global, decadal scales requires highly accurate, stable measurements and retrieval algorithms. Trend uncertainty depends on its magnitude, natural variability, and instrument and retrieval algorithm accuracy and stability. We applied a climate accuracy framework to quantify the impact of absolute calibration on cloud property trend uncertainty. The cloud properties studied were cloud fraction, effective temperature, optical thickness, and effective radius retrieved using the Clouds and the Earth's Radiant Energy System (CERES) Cloud Property Retrieval System, which uses Moderate-resolution Imaging Spectroradiometer measurements (MODIS). Modeling experiments from the fifth phase of the Climate Model Intercomparison Project (CMIP5) agree that net cloud feedback is likely positive but disagree regarding its magnitude, mainly due to uncertainty in shortwave cloud feedback. With the climate accuracy framework we determined the time to detect trends for instruments with various calibration accuracies. We estimated a relationship between cloud property trend uncertainty, cloud feedback, and Equilibrium Climate Sensitivity and also between effective radius trend uncertainty and aerosol indirect effect trends. The direct relationship between instrument accuracy requirements and climate model output provides the level of instrument absolute accuracy needed to reduce climate model projection uncertainty. Different cloud types have varied radiative impacts on the climate system depending on several attributes, such as their thermodynamic phase, altitude, and optical thickness. Therefore, we also conducted these studies by cloud types for a clearer understanding of instrument accuracy requirements needed to detect changes in their cloud properties. Combining this information with the radiative impact of different cloud types helps to prioritize among requirements for future satellite sensors and understanding the climate detection

  15. Non-Invasive Method of Determining Absolute Intracranial Pressure

    NASA Technical Reports Server (NTRS)

    Yost, William T. (Inventor); Cantrell, John H., Jr. (Inventor); Hargens, Alan E. (Inventor)

    2004-01-01

    A method is presented for determining absolute intracranial pressure (ICP) in a patient. Skull expansion is monitored while changes in ICP are induced. The patient's blood pressure is measured when skull expansion is approximately zero. The measured blood pressure is indicative of a reference ICP value. Subsequently, the method causes a known change in ICP and measured the change in skull expansion associated therewith. The absolute ICP is a function of the reference ICP value, the known change in ICP and its associated change in skull expansion; and a measured change in skull expansion.

  16. A highly accurate absolute gravimetric network for Albania, Kosovo and Montenegro

    NASA Astrophysics Data System (ADS)

    Ullrich, Christian; Ruess, Diethard; Butta, Hubert; Qirko, Kristaq; Pavicevic, Bozidar; Murat, Meha

    2016-04-01

    The objective of this project is to establish a basic gravity network in Albania, Kosovo and Montenegro to enable further investigations in geodetic and geophysical issues. Therefore the first time in history absolute gravity measurements were performed in these countries. The Norwegian mapping authority Kartverket is assisting the national mapping authorities in Kosovo (KCA) (Kosovo Cadastral Agency - Agjencia Kadastrale e Kosovës), Albania (ASIG) (Autoriteti Shtetëror i Informacionit Gjeohapësinor) and in Montenegro (REA) (Real Estate Administration of Montenegro - Uprava za nekretnine Crne Gore) in improving the geodetic frameworks. The gravity measurements are funded by Kartverket. The absolute gravimetric measurements were performed from BEV (Federal Office of Metrology and Surveying) with the absolute gravimeter FG5-242. As a national metrology institute (NMI) the Metrology Service of the BEV maintains the national standards for the realisation of the legal units of measurement and ensures their international equivalence and recognition. Laser and clock of the absolute gravimeter were calibrated before and after the measurements. The absolute gravimetric survey was carried out from September to October 2015. Finally all 8 scheduled stations were successfully measured: there are three stations located in Montenegro, two stations in Kosovo and three stations in Albania. The stations are distributed over the countries to establish a gravity network for each country. The vertical gradients were measured at all 8 stations with the relative gravimeter Scintrex CG5. The high class quality of some absolute gravity stations can be used for gravity monitoring activities in future. The measurement uncertainties of the absolute gravity measurements range around 2.5 micro Gal at all stations (1 microgal = 10-8 m/s2). In Montenegro the large gravity difference of 200 MilliGal between station Zabljak and Podgorica can be even used for calibration of relative gravimeters

  17. Chemical composition of French mimosa absolute oil.

    PubMed

    Perriot, Rodolphe; Breme, Katharina; Meierhenrich, Uwe J; Carenini, Elise; Ferrando, Georges; Baldovini, Nicolas

    2010-02-10

    Since decades mimosa (Acacia dealbata) absolute oil has been used in the flavor and perfume industry. Today, it finds an application in over 80 perfumes, and its worldwide industrial production is estimated five tons per year. Here we report on the chemical composition of French mimosa absolute oil. Straight-chain analogues from C6 to C26 with different functional groups (hydrocarbons, esters, aldehydes, diethyl acetals, alcohols, and ketones) were identified in the volatile fraction. Most of them are long-chain molecules: (Z)-heptadec-8-ene, heptadecane, nonadecane, and palmitic acid are the most abundant, and constituents such as 2-phenethyl alcohol, methyl anisate, and ethyl palmitate are present in smaller amounts. The heavier constituents were mainly triterpenoids such as lupenone and lupeol, which were identified as two of the main components. (Z)-Heptadec-8-ene, lupenone, and lupeol were quantified by GC-MS in SIM mode using external standards and represents 6%, 20%, and 7.8% (w/w) of the absolute oil. Moreover, odorant compounds were extracted by SPME and analyzed by GC-sniffing leading to the perception of 57 odorant zones, of which 37 compounds were identified by their odorant description, mass spectrum, retention index, and injection of the reference compound.

  18. Measurement of absolute gravity acceleration in Firenze

    NASA Astrophysics Data System (ADS)

    de Angelis, M.; Greco, F.; Pistorio, A.; Poli, N.; Prevedelli, M.; Saccorotti, G.; Sorrentino, F.; Tino, G. M.

    2011-01-01

    This paper reports the results from the accurate measurement of the acceleration of gravity g taken at two separate premises in the Polo Scientifico of the University of Firenze (Italy). In these laboratories, two separate experiments aiming at measuring the Newtonian constant and testing the Newtonian law at short distances are in progress. Both experiments require an independent knowledge on the local value of g. The only available datum, pertaining to the italian zero-order gravity network, was taken more than 20 years ago at a distance of more than 60 km from the study site. Gravity measurements were conducted using an FG5 absolute gravimeter, and accompanied by seismic recordings for evaluating the noise condition at the site. The absolute accelerations of gravity at the two laboratories are (980 492 160.6 ± 4.0) μGal and (980 492 048.3 ± 3.0) μGal for the European Laboratory for Non-Linear Spectroscopy (LENS) and Dipartimento di Fisica e Astronomia, respectively. Other than for the two referenced experiments, the data here presented will serve as a benchmark for any future study requiring an accurate knowledge of the absolute value of the acceleration of gravity in the study region.

  19. Absolute angular encoder based on optical diffraction

    NASA Astrophysics Data System (ADS)

    Wu, Jian; Zhou, Tingting; Yuan, Bo; Wang, Liqiang

    2015-08-01

    A new encoding method for absolute angular encoder based on optical diffraction was proposed in the present study. In this method, an encoder disc is specially designed that a series of elements are uniformly spaced in one circle and each element is consisted of four diffraction gratings, which are tilted in the directions of 30°, 60°, -60° and -30°, respectively. The disc is illuminated by a coherent light and the diffractive signals are received. The positions of diffractive spots are used for absolute encoding and their intensities are for subdivision, which is different from the traditional optical encoder based on transparent/opaque binary principle. Since the track's width in the disc is not limited in the diffraction pattern, it provides a new way to solve the contradiction between the size and resolution, which is good for minimization of encoder. According to the proposed principle, the diffraction pattern disc with a diameter of 40 mm was made by lithography in the glass substrate. A prototype of absolute angular encoder with a resolution of 20" was built up. Its maximum error was tested as 78" by comparing with a small angle measuring system based on laser beam deflection.

  20. Debiased orbit and absolute-magnitude distributions for near-Earth objects

    NASA Astrophysics Data System (ADS)

    Granvik, Mikael; Morbidelli, Alessandro; Jedicke, Robert; Bolin, Bryce; Bottke, William F.; Beshore, Edward; Vokrouhlický, David; Nesvorný, David; Michel, Patrick

    2018-09-01

    The debiased absolute-magnitude and orbit distributions as well as source regions for near-Earth objects (NEOs) provide a fundamental frame of reference for studies of individual NEOs and more complex population-level questions. We present a new four-dimensional model of the NEO population that describes debiased steady-state distributions of semimajor axis, eccentricity, inclination, and absolute magnitude H in the range 17 < H < 25. The modeling approach improves upon the methodology originally developed by Bottke et al. (2000, Science 288, 2190-2194) in that it is, for example, based on more realistic orbit distributions and uses source-specific absolute-magnitude distributions that allow for a power-law slope that varies with H. We divide the main asteroid belt into six different entrance routes or regions (ER) to the NEO region: the ν6, 3:1J, 5:2J and 2:1J resonance complexes as well as Hungarias and Phocaeas. In addition we include the Jupiter-family comets as the primary cometary source of NEOs. We calibrate the model against NEO detections by Catalina Sky Surveys' stations 703 and G96 during 2005-2012, and utilize the complementary nature of these two systems to quantify the systematic uncertainties associated to the resulting model. We find that the (fitted) H distributions have significant differences, although most of them show a minimum power-law slope at H ∼ 20. As a consequence of the differences between the ER-specific H distributions we find significant variations in, for example, the NEO orbit distribution, average lifetime, and the relative contribution of different ERs as a function of H. The most important ERs are the ν6 and 3:1J resonance complexes with JFCs contributing a few percent of NEOs on average. A significant contribution from the Hungaria group leads to notable changes compared to the predictions by Bottke et al. in, for example, the orbit distribution and average lifetime of NEOs. We predict that there are 962-56+52 (802-42+48

  1. The Impact of Strategy Instruction and Timing of Estimates on Low and High Working-Memory Capacity Readers' Absolute Monitoring Accuracy

    ERIC Educational Resources Information Center

    Linderholm, Tracy; Zhao, Qin

    2008-01-01

    Working-memory capacity, strategy instruction, and timing of estimates were investigated for their effects on absolute monitoring accuracy, which is the difference between estimated and actual reading comprehension test performance. Participants read two expository texts under one of two randomly assigned reading strategy instruction conditions…

  2. Laser interferometry method for absolute measurement of the acceleration of gravity

    NASA Technical Reports Server (NTRS)

    Hudson, O. K.

    1971-01-01

    Gravimeter permits more accurate and precise absolute measurement of g without reference to Potsdam values as absolute standards. Device is basically Michelson laser beam interferometer in which one arm is mass fitted with corner cube reflector.

  3. Absolute Coefficients and the Graphical Representation of Airfoil Characteristics

    NASA Technical Reports Server (NTRS)

    Munk, Max

    1921-01-01

    It is argued that there should be an agreement as to what conventions to use in determining absolute coefficients used in aeronautics and in how to plot those coefficients. Of particular importance are the absolute coefficients of lift and drag. The author argues for the use of the German method over the kind in common use in the United States and England, and for the Continental over the usual American and British method of graphically representing the characteristics of an airfoil. The author notes that, on the whole, it appears that the use of natural absolute coefficients in a polar diagram is the logical method for presentation of airfoil characteristics, and that serious consideration should be given to the advisability of adopting this method in all countries, in order to advance uniformity and accuracy in the science of aeronautics.

  4. Peripheral absolute threshold spectral sensitivity in retinitis pigmentosa.

    PubMed Central

    Massof, R W; Johnson, M A; Finkelstein, D

    1981-01-01

    Dark-adapted spectral sensitivities were measured in the peripheral retinas of 38 patients diagnosed as having typical retinitis pigmentosa (RP) and in 3 normal volunteers. The patients included those having autosomal dominant and autosomal recessive inheritance patterns. Results were analysed by comparisons with the CIE standard scotopic spectral visibility function and with Judd's modification of the photopic spectral visibility function, with consideration of contributions from changes in spectral transmission of preretinal media. The data show 3 general patterns. One group of patients had absolute threshold spectral sensitivities that were fit by Judd's photopic visibility curve. Absolute threshold spectral sensitivities for a second group of patients were fit by a normal scotopic spectral visibility curve. The third group of patients had absolute threshold spectral sensitivities that were fit by a combination of scotopic and photopic spectral visibility curves. The autosomal dominant and autosomal recessive modes of inheritance were represented in each group of patients. These data indicate that RP patients have normal rod and/or cone spectral sensitivities, and support the subclassification of patients described previously by Massof and Finkelstein. PMID:7459312

  5. Effects of impedance mismatch and coaxial cable length on absolute gravimeters

    NASA Astrophysics Data System (ADS)

    Křen, Petr; Pálinkáš, Vojtech; Mašika, Pavel; Vaľko, Miloš

    2017-04-01

    The systematic effects of absolute gravimeters have to be investigated to fully utilize their capabilities in metrology and geosciences. In Křen et al (2016 Metrologia 53 27-40) we found that for an FG5 gravimeter, even a few meter long coaxial cable used for transmission of fringe signal causes systematic features in residuals and errors at the level of 1-2 µGal. In this paper, we present experimental results and appropriate models to explain the effects that were found to be caused by impedance mismatches of electronic components and dispersion effects in coaxial cables of gravimeters. The experimental results have been obtained for analogue and transistor-transistor logic (TTL) compatible signals in the FG5-215 gravimeter and for a TTL signal in the FG5X-251 gravimeter. We found that dispersion and impedance mismatch effects are similar for both gravimeters. Furthermore, we describe a model of the dispersion that allows an evaluation of the effect/correction for a given range of the free-fall and thus it is also applicable to other gravimeters. The effect of impedance mismatch for the analogue fringe signal is modelled as an effect of the reflected electronic signal on the evaluation of zero-crossings. The applicability of this model for TTL signal is also discussed.

  6. Impact of an electronic medication administration record on medication administration efficiency and errors.

    PubMed

    McComas, Jeffery; Riingen, Michelle; Chae Kim, Son

    2014-12-01

    The study aims were to evaluate the impact of electronic medication administration record implementation on medication administration efficiency and occurrence of medication errors as well as to identify the predictors of medication administration efficiency in an acute care setting. A prospective, observational study utilizing time-and-motion technique was conducted before and after electronic medication administration record implementation in November 2011. A total of 156 cases of medication administration activities (78 pre- and 78 post-electronic medication administration record) involving 38 nurses were observed at the point of care. A separate retrospective review of the hospital Midas+ medication error database was also performed to collect the rates and origin of medication errors for 6 months before and after electronic medication administration record implementation. The mean medication administration time actually increased from 11.3 to 14.4 minutes post-electronic medication administration record (P = .039). In a multivariate analysis, electronic medication administration record was not a predictor of medication administration time, but the distractions/interruptions during medication administration process were significant predictors. The mean hospital-wide medication errors significantly decreased from 11.0 to 5.3 events per month post-electronic medication administration record (P = .034). Although no improvement in medication administration efficiency was observed, electronic medication administration record improved the quality of care with a significant decrease in medication errors.

  7. Neural Sensitivity to Absolute and Relative Anticipated Reward in Adolescents

    PubMed Central

    Vaidya, Jatin G.; Knutson, Brian; O'Leary, Daniel S.; Block, Robert I.; Magnotta, Vincent

    2013-01-01

    Adolescence is associated with a dramatic increase in risky and impulsive behaviors that have been attributed to developmental differences in neural processing of rewards. In the present study, we sought to identify age differences in anticipation of absolute and relative rewards. To do so, we modified a commonly used monetary incentive delay (MID) task in order to examine brain activity to relative anticipated reward value (neural sensitivity to the value of a reward as a function of other available rewards). This design also made it possible to examine developmental differences in brain activation to absolute anticipated reward magnitude (the degree to which neural activity increases with increasing reward magnitude). While undergoing fMRI, 18 adolescents and 18 adult participants were presented with cues associated with different reward magnitudes. After the cue, participants responded to a target to win money on that trial. Presentation of cues was blocked such that two reward cues associated with $.20, $1.00, or $5.00 were in play on a given block. Thus, the relative value of the $1.00 reward varied depending on whether it was paired with a smaller or larger reward. Reflecting age differences in neural responses to relative anticipated reward (i.e., reference dependent processing), adults, but not adolescents, demonstrated greater activity to a $1 reward when it was the larger of the two available rewards. Adults also demonstrated a more linear increase in ventral striatal activity as a function of increasing absolute reward magnitude compared to adolescents. Additionally, reduced ventral striatal sensitivity to absolute anticipated reward (i.e., the difference in activity to medium versus small rewards) correlated with higher levels of trait Impulsivity. Thus, ventral striatal activity in anticipation of absolute and relative rewards develops with age. Absolute reward processing is also linked to individual differences in Impulsivity. PMID:23544046

  8. Absolute flux density calibrations of radio sources: 2.3 GHz

    NASA Technical Reports Server (NTRS)

    Freiley, A. J.; Batelaan, P. D.; Bathker, D. A.

    1977-01-01

    A detailed description of a NASA/JPL Deep Space Network program to improve S-band gain calibrations of large aperture antennas is reported. The program is considered unique in at least three ways; first, absolute gain calibrations of high quality suppressed-sidelobe dual mode horns first provide a high accuracy foundation to the foundation to the program. Second, a very careful transfer calibration technique using an artificial far-field coherent-wave source was used to accurately obtain the gain of one large (26 m) aperture. Third, using the calibrated large aperture directly, the absolute flux density of five selected galactic and extragalactic natural radio sources was determined with an absolute accuracy better than 2 percent, now quoted at the familiar 1 sigma confidence level. The follow-on considerations to apply these results to an operational network of ground antennas are discussed. It is concluded that absolute gain accuracies within + or - 0.30 to 0.40 db are possible, depending primarily on the repeatability (scatter) in the field data from Deep Space Network user stations.

  9. Assessing epistemic sophistication by considering domain-specific absolute and multiplicistic beliefs separately.

    PubMed

    Peter, Johannes; Rosman, Tom; Mayer, Anne-Kathrin; Leichner, Nikolas; Krampen, Günter

    2016-06-01

    Particularly in higher education, not only a view of science as a means of finding absolute truths (absolutism), but also a view of science as generally tentative (multiplicism) can be unsophisticated and obstructive for learning. Most quantitative epistemic belief inventories neglect this and understand epistemic sophistication as disagreement with absolute statements. This article suggests considering absolutism and multiplicism as separate dimensions. Following our understanding of epistemic sophistication as a cautious and reluctant endorsement of both positions, we assume evaluativism (a contextually adaptive view of knowledge as personally constructed and evidence-based) to be reflected by low agreement with both generalized absolute and generalized multiplicistic statements. Three studies with a total sample size of N = 416 psychology students were conducted. A domain-specific inventory containing both absolute and multiplicistic statements was developed. Expectations were tested by exploratory factor analysis, confirmatory factor analysis, and correlational analyses. Results revealed a two-factor solution with an absolute and a multiplicistic factor. Criterion validity of both factors was confirmed. Cross-sectional analyses revealed that agreement to generalized multiplicistic statements decreases with study progress. Moreover, consistent with our understanding of epistemic sophistication as a reluctant attitude towards generalized epistemic statements, evidence for a negative relationship between epistemic sophistication and need for cognitive closure was found. We recommend including multiplicistic statements into epistemic belief questionnaires and considering them as a separate dimension, especially when investigating individuals in later stages of epistemic development (i.e., in higher education). © 2015 The British Psychological Society.

  10. LUNAR DUST GRAIN CHARGING BY ELECTRON IMPACT: COMPLEX ROLE OF SECONDARY ELECTRON EMISSIONS IN SPACE ENVIRONMENTS

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Abbas, M. M.; Craven, P. D.; LeClair, A. C.

    2010-08-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions (SEEs). The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. Knowledge of the dust grain charges and equilibrium potentials is important for understanding a variety of physical and dynamical processes in the interstellar medium, and heliospheric, interplanetary/planetary, and lunar environments. It has been well recognized that the charging properties of individualmore » micron-/submicron-size dust grains are expected to be substantially different from the corresponding values for bulk materials. In this paper, we present experimental results on the charging of individual 0.2-13 {mu}m size dust grains selected from Apollo 11 and 17 dust samples, and spherical silica particles by exposing them to mono-energetic electron beams in the 10-200 eV energy range. The dust charging process by electron impact involving the SEEs discussed is found to be a complex charging phenomenon with strong particle size dependence. The measurements indicate substantial differences between the polarity and magnitude of the dust charging rates of individual small-size dust grains, and the measurements and model properties of corresponding bulk materials. A more comprehensive plan of measurements of the charging properties of individual dust grains for developing a database for realistic models of dust charging in astrophysical and lunar environments is in progress.« less

  11. Lunary Dust Grain Charging by Electron Impact: Complex Role of Secondary Electron Emissions in Space Environments

    NASA Technical Reports Server (NTRS)

    Abbas, M. M.; Tankosic, D.; Crave, P. D.; LeClair, A.; Spann, J. F.

    2010-01-01

    Dust grains in various astrophysical environments are generally charged electrostatically by photoelectric emissions with radiation from nearby sources, or by electron/ion collisions by sticking or secondary electron emissions (SEES). The high vacuum environment on the lunar surface leads to some unusual physical and dynamical phenomena involving dust grains with high adhesive characteristics, and levitation and transportation over long distances. Knowledge of the dust grain charges and equilibrium potentials is important for understanding a variety of physical and dynamical processes in the interstellar medium, and heliospheric, interplanetary/ planetary, and lunar environments. It has been well recognized that the charging properties of individual micron-/submicron-size dust grains are expected to be substantially different from the corresponding values for bulk materials. In this paper, we present experimental results on the charging of individual 0.2-13 m size dust grains selected from Apollo 11 and 17 dust samples, and spherical silica particles by exposing them to mono-energetic electron beams in the 10-200 eV energy range. The dust charging process by electron impact involving the SEES discussed is found to be a complex charging phenomenon with strong particle size dependence. The measurements indicate substantial differences between the polarity and magnitude of the dust charging rates of individual small-size dust grains, and the measurements and model properties of corresponding bulk materials. A more comprehensive plan of measurements of the charging properties of individual dust grains for developing a database for realistic models of dust charging in astrophysical and lunar environments is in progress.

  12. Absolute photon-flux measurements in the vacuum ultraviolet

    NASA Technical Reports Server (NTRS)

    Samson, J. A. R.; Haddad, G. N.

    1974-01-01

    Absolute photon-flux measurements in the vacuum ultraviolet have extended to short wavelengths by use of rare-gas ionization chambers. The technique involves the measurement of the ion current as a function of the gas pressure in the ion chamber. The true value of the ion current, and hence the absolute photon flux, is obtained by extrapolating the ion current to zero gas pressure. Examples are given at 162 and 266 A. The short-wavelength limit is determined only by the sensitivity of the current-measuring apparatus and by present knowledge of the photoionization processes that occur in the rate gases.

  13. Extracellular Electron Transfer and Survival Strategies in Acid Mine Drainage Impacted Soils

    NASA Astrophysics Data System (ADS)

    Gorby, Y. A.; Senko, J.

    2011-12-01

    Acid mine drainage (AMD) is a prominent and increasing problem in the greater Appalachian region of the United States and throughout the world. Recognition of the importance of extracellular electron transfer (EET) in microbial communities has provided a fertile research environment for multidisciplinary collaborations to emerge and effectively address complex questions with important environmental implications. Our research focuses on the components, strategies and mechanisms of EET in soil systems impacted by AMD and extends to other biogeochemical systems typified by steep redox gradients. Organisms within acid mine drainage use Fe(II) as their primary electron donor and couple Fe(II) oxidation to the reduction of oxygen as the terminal electron acceptor. Biogenic minerals formed by this process completely encase microbes in think deposits that would seem to limit diffusion of both Fe(II) and O2 for access by the organisms. We have developed methods for catalytically removing biogenic minerals revealing microorganisms and a fine network of filamentous extracellular material. Here we present a status report of our efforts to characterize the molecular and electronic properties of these filaments and to address the hypothesis that at least some of these filaments are electrically conductive microbial nanowires that facilitate electron transfer reactions within this complex biogeochemical system.

  14. Stimulus Probability Effects in Absolute Identification

    ERIC Educational Resources Information Center

    Kent, Christopher; Lamberts, Koen

    2016-01-01

    This study investigated the effect of stimulus presentation probability on accuracy and response times in an absolute identification task. Three schedules of presentation were used to investigate the interaction between presentation probability and stimulus position within the set. Data from individual participants indicated strong effects of…

  15. Absolute gravity measurements in California

    NASA Astrophysics Data System (ADS)

    Zumberge, M. A.; Sasagawa, G.; Kappus, M.

    1986-08-01

    An absolute gravity meter that determines the local gravitational acceleration by timing a freely falling mass with a laser interferometer has been constructed. The instrument has made measurements at 11 sites in California, four in Nevada, and one in France. The uncertainty in the results is typically 10 microgal. Repeated measurements have been made at several of the sites; only one shows a substantial change in gravity.

  16. Relational versus absolute representation in categorization.

    PubMed

    Edwards, Darren J; Pothos, Emmanuel M; Perlman, Amotz

    2012-01-01

    This study explores relational-like and absolute-like representations in categorization. Although there is much evidence that categorization processes can involve information about both the particular physical properties of studied instances and abstract (relational) properties, there has been little work on the factors that lead to one kind of representation as opposed to the other. We tested 370 participants in 6 experiments, in which participants had to classify new items into predefined artificial categories. In 4 experiments, we observed a predominantly relational-like mode of classification, and in 2 experiments we observed a shift toward an absolute-like mode of classification. These results suggest 3 factors that promote a relational-like mode of classification: fewer items per group, more training groups, and the presence of a time delay. Overall, we propose that less information about the distributional properties of a category or weaker memory traces for the category exemplars (induced, e.g., by having smaller categories or a time delay) can encourage relational-like categorization.

  17. Theoretical study of ArH+ dissociative recombination and electron-impact vibrational excitation

    NASA Astrophysics Data System (ADS)

    Abdoulanziz, A.; Colboc, F.; Little, D. A.; Moulane, Y.; Mezei, J. Zs; Roueff, E.; Tennyson, J.; Schneider, I. F.; Laporta, V.

    2018-06-01

    Cross sections are presented for dissociative recombination and electron-impact vibrational excitation of the ArH+ molecular ion at electron energies appropriate for the interstellar environment. The R-matrix method is employed to determine the molecular structure data, i.e. the position and width of the resonance states. The cross sections and the corresponding Maxwellian rate coefficients are computed using a method based on the Multichannel Quantum Defect Theory. The main result of the paper is the very low dissociative recombination rate found at temperatures below 1000K. This is in agreement with the previous upper limit measurement in merged beams and offers a realistic explanation to the presence of ArH+ in exotic interstellar conditions.

  18. Standardization approaches in absolute quantitative proteomics with mass spectrometry.

    PubMed

    Calderón-Celis, Francisco; Encinar, Jorge Ruiz; Sanz-Medel, Alfredo

    2017-07-31

    Mass spectrometry-based approaches have enabled important breakthroughs in quantitative proteomics in the last decades. This development is reflected in the better quantitative assessment of protein levels as well as to understand post-translational modifications and protein complexes and networks. Nowadays, the focus of quantitative proteomics shifted from the relative determination of proteins (ie, differential expression between two or more cellular states) to absolute quantity determination, required for a more-thorough characterization of biological models and comprehension of the proteome dynamism, as well as for the search and validation of novel protein biomarkers. However, the physico-chemical environment of the analyte species affects strongly the ionization efficiency in most mass spectrometry (MS) types, which thereby require the use of specially designed standardization approaches to provide absolute quantifications. Most common of such approaches nowadays include (i) the use of stable isotope-labeled peptide standards, isotopologues to the target proteotypic peptides expected after tryptic digestion of the target protein; (ii) use of stable isotope-labeled protein standards to compensate for sample preparation, sample loss, and proteolysis steps; (iii) isobaric reagents, which after fragmentation in the MS/MS analysis provide a final detectable mass shift, can be used to tag both analyte and standard samples; (iv) label-free approaches in which the absolute quantitative data are not obtained through the use of any kind of labeling, but from computational normalization of the raw data and adequate standards; (v) elemental mass spectrometry-based workflows able to provide directly absolute quantification of peptides/proteins that contain an ICP-detectable element. A critical insight from the Analytical Chemistry perspective of the different standardization approaches and their combinations used so far for absolute quantitative MS-based (molecular and

  19. Towards absolute laser spectroscopic CO2 isotope ratio measurements

    NASA Astrophysics Data System (ADS)

    Anyangwe Nwaboh, Javis; Werhahn, Olav; Ebert, Volker

    2017-04-01

    Knowledge of isotope composition of carbon dioxide (CO2) in the atmosphere is necessary to identify sources and sinks of this key greenhouse gas. In the last years, laser spectroscopic techniques such as cavity ring-down spectroscopy (CRDS) and tunable diode laser absorption spectroscopy (TDLAS) have been shown to perform accurate isotope ratio measurements for CO2 and other gases like water vapour (H2O) [1,2]. Typically, isotope ratios are reported in literature referring to reference materials provided by e.g. the International Atomic Energy Agency (IAEA). However, there could be some benefit if field deployable absolute isotope ratio measurement methods were developed to address issues such as exhausted reference material like the Pee Dee Belemnite (PDB) standard. Absolute isotope ratio measurements would be particularly important for situations where reference materials do not even exist. Here, we present CRDS and TDLAS-based absolute isotope ratios (13C/12C ) in atmospheric CO2. We demonstrate the capabilities of the used methods by measuring CO2 isotope ratios in gas standards. We compare our results to values reported for the isotope certified gas standards. Guide to the expression of uncertainty in measurement (GUM) compliant uncertainty budgets on the CRDS and TDLAS absolute isotope ratio measurements are presented, and traceability is addressed. We outline the current impediments in realizing high accuracy absolute isotope ratio measurements using laser spectroscopic methods, propose solutions and the way forward. Acknowledgement Parts of this work have been carried out within the European Metrology Research Programme (EMRP) ENV52 project-HIGHGAS. The EMRP is jointly funded by the EMRP participating countries within EURAMET and the European Union. References [1] B. Kühnreich, S. Wagner, J. C. Habig,·O. Möhler, H. Saathoff, V. Ebert, Appl. Phys. B 119:177-187 (2015). [2] E. Kerstel, L. Gianfrani, Appl. Phys. B 92, 439-449 (2008).

  20. Direct Electron Impact Excitation of Rydberg-Valence States of Molecular Nitrogen

    NASA Astrophysics Data System (ADS)

    Malone, C. P.; Johnson, P. V.; Liu, X.; Ajdari, B.; Muleady, S.; Kanik, I.; Khakoo, M. A.

    2012-12-01

    Collisions between electrons and neutral N2 molecules result in emissions that provide an important diagnostic probe for understanding the ionospheric energy balance and the effects of space weather in upper atmospheres. Also, transitions to singlet ungerade states cause N2 to be a strong absorber of solar radiation in the EUV spectral range where many ro-vibrational levels of these Rydberg-valence (RV) states are predissociative. Thus, their respective excitation and emission cross sections are important parameters for understanding the [N]/[N2] ratio in the thermosphere of nitrogen dominated atmospheres. The following work provides improved constraints on absolute and relative excitation cross sections of numerous RV states of N2, enabling more physically accurate atmospheric modeling. Here, we present recent integral cross sections (ICSs) for electron impact excitation of RV states of N2 [6], which were based on the differential cross sections (DCSs) derived from electron energy-loss (EEL) spectra of [5]. This work resulted in electronic excitation cross sections over the following measured vibrational levels: b 1Πu (v‧=0-14), c3 1Πu (v‧=0-3), o3 1Πu (v‧=0-3), b‧ 1Σu+ (v‧=0-10), c‧4 1Σu+ (v‧=0-3), G 3Πu (v‧=0-3), and F 3Πu (v‧=0-3). We further adjusted the cross sections of the RV states by extending the vibronic contributions to unmeasured v‧-levels via the relative excitation probabilities (REPs) as discussed in [6]. This resulted in REP-scaled ICSs over the following vibrational levels for the singlet ungerade states: b(0-19), c3(0-4), o3(0-4), b‧(0-16), and c‧4(0-8). Comparison of the ICSs of [6] with available EEL based measurements, theoretical calculations, and emission based work generally shows good agreement within error estimations, except with the recent reevaluation provided by [1]. Further, we have extended these results, using the recent EEL data of [3], to include the unfolding of better resolved features above ~13

  1. Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes

    PubMed Central

    Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

    2017-01-01

    Background: Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. Objective: To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. Materials and Methods: We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Results: Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. Conclusion: These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. SUMMARY Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation.Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus

  2. Effect of Absolute From Hibiscus syriacus L. Flower on Wound Healing in Keratinocytes.

    PubMed

    Yoon, Seok Won; Lee, Kang Pa; Kim, Do-Yoon; Hwang, Dae Il; Won, Kyung-Jong; Lee, Dae Won; Lee, Hwan Myung

    2017-01-01

    Proliferation and migration of keratinocytes are essential for the repair of cutaneous wounds. Hibiscus syriacus L. has been used in Asian medicine; however, research on keratinocytes is inadequate. To establish the dermatological properties of absolute from Hibiscus syriacus L. flower (HSF) and to provide fundamental research for alternative medicine. We identified the composition of HSF absolute using gas chromatography-mass spectrometry analysis. We also examined the effect of HSF absolute in HaCaT cells using the XTT assay, Boyden chamber assay, sprout-out growth assay, and western blotting. We conducted an in-vivo wound healing assay in rat tail-skin. Ten major active compounds were identified from HSF absolute. As determined by the XTT assay, Boyden chamber assay, and sprout-out growth assay results, HSF absolute exhibited similar effects as that of epidermal growth factor on the proliferation and migration patterns of keratinocytes (HaCaT cells), which were significantly increased after HSF absolute treatment. The expression levels of the phosphorylated signaling proteins relevant to proliferation, including extracellular signal-regulated kinase 1/2 (Erk 1/2) and Akt, were also determined by western blot analysis. These results of our in-vitro and ex-vivo studies indicate that HSF absolute induced cell growth and migration of HaCaT cells by phosphorylating both Erk 1/2 and Akt. Moreover, we confirmed the wound-healing effect of HSF on injury of the rat tail-skin. Therefore, our results suggest that HSF absolute is promising for use in cosmetics and alternative medicine. Hisbiscus syriacus L. flower absolute increases HaCaT cell migration and proliferation. Hisbiscus syriacus L. flower absolute regulates phosphorylation of ERK 1/2 and Akt in HaCaT cell.Treatment with Hisbiscus syriacus L. flower induced sprout outgrowth.The wound in the tail-skin of rat was reduced by Hisbiscus syriacus L. flower absolute Abbreviations used: HSF: Hibiscus syriacus L. flower

  3. Terpecurcumins A-I from the rhizomes of Curcuma longa: absolute configuration and cytotoxic activity.

    PubMed

    Lin, Xionghao; Ji, Shuai; Li, Rui; Dong, Yinhui; Qiao, Xue; Hu, Hongbo; Yang, Wenzhi; Guo, Dean; Tu, Pengfei; Ye, Min

    2012-12-28

    Terpecurcumins A-I (1-9), together with three known analogues (10-12), were isolated from the rhizomes of Curcuma longa (turmeric). They were derived from the hybridization of curcuminoids and bisabolanes. The structures and absolute configurations of 1-9 were elucidated on the basis of extensive spectroscopic data analysis, including NMR and electronic circular dichroism spectra. The configuration of 10 was further confirmed by X-ray crystallography. A plausible biogenetic relationship for 1-12 is proposed. Compounds 4, 6, 7, 10, and 11 showed higher cytotoxic activities (IC(50), 10.3-19.4 μM) than curcumin (IC(50), 31.3-49.2 μM) against human cancer cell lines (A549, HepG2, and MDA-MB-231).

  4. The fading American dream: Trends in absolute income mobility since 1940.

    PubMed

    Chetty, Raj; Grusky, David; Hell, Maximilian; Hendren, Nathaniel; Manduca, Robert; Narang, Jimmy

    2017-04-28

    We estimated rates of "absolute income mobility"-the fraction of children who earn more than their parents-by combining data from U.S. Census and Current Population Survey cross sections with panel data from de-identified tax records. We found that rates of absolute mobility have fallen from approximately 90% for children born in 1940 to 50% for children born in the 1980s. Increasing Gross Domestic Product (GDP) growth rates alone cannot restore absolute mobility to the rates experienced by children born in the 1940s. However, distributing current GDP growth more equally across income groups as in the 1940 birth cohort would reverse more than 70% of the decline in mobility. These results imply that reviving the "American dream" of high rates of absolute mobility would require economic growth that is shared more broadly across the income distribution. Copyright © 2017, American Association for the Advancement of Science.

  5. 34 CFR 648.33 - What priorities and absolute preferences does the Secretary establish?

    Code of Federal Regulations, 2011 CFR

    2011-07-01

    ... 34 Education 3 2011-07-01 2011-07-01 false What priorities and absolute preferences does the... AREAS OF NATIONAL NEED How Does the Secretary Make an Award? § 648.33 What priorities and absolute... area of national need and gives absolute preference to one or more of the general disciplines and sub...

  6. 34 CFR 648.33 - What priorities and absolute preferences does the Secretary establish?

    Code of Federal Regulations, 2010 CFR

    2010-07-01

    ... 34 Education 3 2010-07-01 2010-07-01 false What priorities and absolute preferences does the... AREAS OF NATIONAL NEED How Does the Secretary Make an Award? § 648.33 What priorities and absolute... area of national need and gives absolute preference to one or more of the general disciplines and sub...

  7. Electron Impact Inner-shell Ionization including relativistic corrections.

    NASA Astrophysics Data System (ADS)

    Saha, Bidhan C.; Alfaz Uddin, M.; Basak, Arun K.

    2007-04-01

    We report a simple method to evaluate the electron impact inner-shell ionization cross sections at ultra high energy regime; there still remains a sparse cross sections due to lack of reliable method. To extend the validity domains of the siBED model [1] in terms of targets and incident energies in this work we modified the RQIBED model [2], and denoted it as MUIBED. It is examined for the description of the experimental EIICS data of various target atoms up to E=250MeV. Details will be presented at the meeting. [1] W. M. Huo, Phys. Rev A 64, 042719 (2001). [2] M. A. Uddin, A. K. F. Haque, M. S. Mahbub, K. R. Karim, A. K. Basak and B. C. Saha, Phys. Rev. A 71, 032715 (2005).

  8. Transition from convective to absolute Raman instability via the longitudinal relativistic effect by using Vlasov-Maxwell simulations

    NASA Astrophysics Data System (ADS)

    Wang, Q.; Liu, Z. J.; Zheng, C. Y.; Xiao, C. Z.; Feng, Q. S.; Zhang, H. C.; He, X. T.

    2018-01-01

    The longitudinal relativistic effect on stimulated Raman backscattering (SRBS) is investigated by using one-dimensional (1D) Vlasov-Maxwell simulations. Using a short backscattered light seed pulse with a very small amplitude, the linear gain spectra of SRBS in the strongly convective regime is presented by combining the relativistic and non-relativistic 1D Vlasov-Maxwell simulations, which is in agreement with the steady-state linear theory. More interestingly, by considering transition from convective to absolute instability due to electron trapping, we successfully predict the critical duration of the seed which can just trigger the kinetic inflation of the excited SRBS after the seed leaves the simulation box. The critical duration in the relativistic case is much shorter than that in the nonrelativistic case, which indicates that the kinetic inflation more easily occurs in the relativistic case than in the nonrelativistic case. In the weakly convective regime, the transition from convective to absolute instability for SRBS can directly occur in the linear regime due to the longitudinal relativistic modification. For the same pump, our simulations first demonstrate that the SRBS excited by a short and small seed pulse is a convective instability in the nonrelativistic case but becomes an absolute instability due to the decrease of the linear Landau damping from the longitudinal relativistic modification in the relativistic case. In more detail, the growth rate of the backscattered light is also in excellent agreement with theoretical prediction.

  9. Impact of Electronic Teaching Materials on Process of Education--Results of an Experiment

    ERIC Educational Resources Information Center

    Záhorec, Ján; Hašková, Alena; Munk, Michal

    2010-01-01

    In their paper the authors deal with the vital issues of creation and application of electronic teaching materials for natural science subjects teaching. They describe an experimental examination of qualitative impact of these aids on education. The authors present a part of research results, which they obtained in a major research focused on…

  10. Integrated poly(dimethysiloxane) with an intrinsic nonfouling property approaching "absolute" zero background in immunoassays.

    PubMed

    Ma, Hongwei; Wu, Yuanzi; Yang, Xiaoli; Liu, Xing; He, Jianan; Fu, Long; Wang, Jie; Xu, Hongke; Shi, Yi; Zhong, Renqian

    2010-08-01

    The key to achieve a highly sensitive and specific protein microarray assay is to prevent nonspecific protein adsorption to an "absolute" zero level because any signal amplification method will simultaneously amplify signal and noise. Here, we develop a novel solid supporting material, namely, polymer coated initiator integrated poly(dimethysiloxane) (iPDMS), which was able to achieve such "absolute" zero (i.e., below the detection limit of instrument). The implementation of this iPDMS enables practical and high-quality multiplexed enzyme-linked immunosorbent assay (ELISA) of 11 tumor markers. This iPDMS does not need any blocking steps and only require mild washing conditions. It also uses on an average 8-fold less capture antibodies compared with the mainstream nitrocellulose (NC) film. Besides saving time and materials, iPDMS achieved a limit-of-detection (LOD) as low as 19 pg mL(-1), which is sufficiently low for most current clinical diagnostic applications. We expect to see an immediate impact of this iPDMS on the realization of the great potential of protein microarray in research and practical uses such as large scale and high-throughput screening, clinical diagnosis, inspection, and quarantine.

  11. Absolute branching fraction measurements of exclusive D+ semileptonic decays.

    PubMed

    Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shipsey, I P J; Adams, G S; Chasse, M; Cravey, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Muramatsu, H; Park, C S; Park, W; Thorndike, E H; Coan, T E; Gao, Y S; Liu, F; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dambasuren, E; Dorjkhaidav, O; Li, J; Menaa, N; Mountain, R; Nandakumar, R; Randrianarivony, K; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Briere, R A; Chen, G P; Chen, J; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Berkelman, K; Cassel, D G; Crede, V; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Gibbons, L; Gittelman, B; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Meyer, T O; Onyisi, P U E; Patterson, J R; Peterson, D; Phillips, E A; Pivarski, J; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shi, X; Shepherd, M R; Stroiney, S; Sun, W M; Urner, D; Weaver, K M; Wilksen, T; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Patel, R; Potlia, V; Stoeck, H; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Gollin, G D; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; Williams, J; Wiss, J; Edwards, K W; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Hietala, J; Kubota, Y; Klein, T; Lang, B W; Li, S Z; Poling, R; Scott, A W; Smith, A; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ernst, J; Mahmood, A H; Severini, H; Asner, D M; Dytman, S A; Love, W; Mehrabyan, S; Mueller, J A; Savinov, V; Li, Z; Lopez, A; Mendez, H; Ramirez, J

    2005-10-28

    Using data collected at the psi(3770) resonance with the CLEO-c detector at the Cornell e+e- storage ring, we present improved measurements of the absolute branching fractions of D+decays to K0e+ve, pi0e+ve, K*0e+ve, and p0e+ve, and the first observation and absolute branching fraction measurement of D+ --> omega e+ve. We also report the most precise tests to date of isospin invariance in semileptonic D0 and D+ decays.

  12. Absolute optical extinction measurements of single nano-objects by spatial modulation spectroscopy using a white lamp

    NASA Astrophysics Data System (ADS)

    Billaud, Pierre; Marhaba, Salem; Grillet, Nadia; Cottancin, Emmanuel; Bonnet, Christophe; Lermé, Jean; Vialle, Jean-Louis; Broyer, Michel; Pellarin, Michel

    2010-04-01

    This article describes a high sensitivity spectrophotometer designed to detect the overall extinction of light by a single nanoparticle (NP) in the 10-4-10-5 relative range, using a transmission measurement configuration. We focus here on the simple and low cost scheme where a white lamp is used as a light source, permitting easy and broadband extinction measurements (300-900 nm). Using a microscope, in a confocal geometry, an increased sensitivity is reached thanks to a modulation of the NP position under the light spot combined with lock-in detection. Moreover, it is shown that this technique gives access to the absolute extinction cross-sections of the single NP provided that the incident electromagnetic field distribution experienced by the NP is accurately characterized. In this respect, an experimental procedure to characterize the light spot profile in the focal plane, using a reference NP as a probe, is also laid out. The validity of this approach is discussed and confirmed by comparing experimental intensity distributions to theoretical calculations taking into account the vector character of the tightly focused beam. The calibration procedure permitting to obtain the absolute extinction cross-section of the probed NP is then fully described. Finally, the force of the present technique is illustrated through selected examples concerning spherical and slightly elongated gold and silver NPs. Absolute extinction measurements are found to be in good consistency with the NP size and shape independently obtained from transmission electron microscopy, showing that spatial modulation spectroscopy is a powerful tool to get an optical fingerprint of the NP.

  13. The effect of modeled absolute timing variability and relative timing variability on observational learning.

    PubMed

    Grierson, Lawrence E M; Roberts, James W; Welsher, Arthur M

    2017-05-01

    There is much evidence to suggest that skill learning is enhanced by skill observation. Recent research on this phenomenon indicates a benefit of observing variable/erred demonstrations. In this study, we explore whether it is variability within the relative organization or absolute parameterization of a movement that facilitates skill learning through observation. To do so, participants were randomly allocated into groups that observed a model with no variability, absolute timing variability, relative timing variability, or variability in both absolute and relative timing. All participants performed a four-segment movement pattern with specific absolute and relative timing goals prior to and following the observational intervention, as well as in a 24h retention test and transfers tests that featured new relative and absolute timing goals. Absolute timing error indicated that all groups initially acquired the absolute timing, maintained their performance at 24h retention, and exhibited performance deterioration in both transfer tests. Relative timing error revealed that the observation of no variability and relative timing variability produced greater performance at the post-test, 24h retention and relative timing transfer tests, but for the no variability group, deteriorated at absolute timing transfer test. The results suggest that the learning of absolute timing following observation unfolds irrespective of model variability. However, the learning of relative timing benefits from holding the absolute features constant, while the observation of no variability partially fails in transfer. We suggest learning by observing no variability and variable/erred models unfolds via similar neural mechanisms, although the latter benefits from the additional coding of information pertaining to movements that require a correction. Copyright © 2017 Elsevier B.V. All rights reserved.

  14. A New Gimmick for Assigning Absolute Configuration.

    ERIC Educational Resources Information Center

    Ayorinde, F. O.

    1983-01-01

    A five-step procedure is provided to help students in making the assignment absolute configuration less bothersome. Examples for both single (2-butanol) and multi-chiral carbon (3-chloro-2-butanol) molecules are included. (JN)

  15. Absolute Equilibrium Entropy

    NASA Technical Reports Server (NTRS)

    Shebalin, John V.

    1997-01-01

    The entropy associated with absolute equilibrium ensemble theories of ideal, homogeneous, fluid and magneto-fluid turbulence is discussed and the three-dimensional fluid case is examined in detail. A sigma-function is defined, whose minimum value with respect to global parameters is the entropy. A comparison is made between the use of global functions sigma and phase functions H (associated with the development of various H-theorems of ideal turbulence). It is shown that the two approaches are complimentary though conceptually different: H-theorems show that an isolated system tends to equilibrium while sigma-functions allow the demonstration that entropy never decreases when two previously isolated systems are combined. This provides a more complete picture of entropy in the statistical mechanics of ideal fluids.

  16. Scanning electron microscope/energy dispersive x ray analysis of impact residues in LDEF tray clamps

    NASA Technical Reports Server (NTRS)

    Bernhard, Ronald P.; Durin, Christian; Zolensky, Michael E.

    1993-01-01

    Detailed optical scanning of tray clamps is being conducted in the Facility for the Optical Inspection of Large Surfaces at JSC to locate and document impacts as small as 40 microns in diameter. Residues from selected impacts are then being characterized by Scanning Electron Microscopy/Energy Dispersive X-ray Analysis at CNES. Results from this analysis will be the initial step to classifying projectile residues into specific sources.

  17. Cosmic-ray electrons and galactic radio emission - A conflict

    NASA Technical Reports Server (NTRS)

    Badhwar, G. D.; Daniel, R. R.; Stephens, S. A.

    1977-01-01

    An analysis which takes into account the observed energy spectrum of cosmic-ray electrons above 5 GeV and calculated mean magnetic field data shows that the observed spectral index of the radio continuum in the Galaxy is in conflict with some of the cosmic-ray electron measurements. It is found that the absolute intensities of cosmic-ray electrons measured by some of the experimenters are so low that they cannot be reconciled either with the interstellar magnetic field limits or with the extent of the galactic disk toward the anticenter.

  18. Absolute instabilities of travelling wave solutions in a Keller-Segel model

    NASA Astrophysics Data System (ADS)

    Davis, P. N.; van Heijster, P.; Marangell, R.

    2017-11-01

    We investigate the spectral stability of travelling wave solutions in a Keller-Segel model of bacterial chemotaxis with a logarithmic chemosensitivity function and a constant, sublinear, and linear consumption rate. Linearising around the travelling wave solutions, we locate the essential and absolute spectrum of the associated linear operators and find that all travelling wave solutions have parts of the essential spectrum in the right half plane. However, we show that in the case of constant or sublinear consumption there exists a range of parameters such that the absolute spectrum is contained in the open left half plane and the essential spectrum can thus be weighted into the open left half plane. For the constant and sublinear consumption rate models we also determine critical parameter values for which the absolute spectrum crosses into the right half plane, indicating the onset of an absolute instability of the travelling wave solution. We observe that this crossing always occurs off of the real axis.

  19. Electron impact excitation of NeIII intercombination lines

    NASA Astrophysics Data System (ADS)

    Daw, Adrian; McLaughlin, Brendan M.; Bell, Kenneth L.

    2000-06-01

    Observations on the spectra of doubly ionized neon (NeIII) have been recently recorded below 25O Å(A. E. Livington, R. Buttner, A. S. Zacarias, B. Kraus, K-H Schartner, F. Folkmann and P. H. Mokler, J. Opt. Soc. Am. B 14) 522-525 (1997).. This work together with previous studies give line intensies which may be used as density diagnostics but required accurate collision strengths and transition probabilities for their interpretation. Recent studies on electron collisions with NeIII ions using the R-matrix approach (B. M. McLaughlin and K. L. Bell, J. Phys. B. 33), 597 (2000). for Δ n=0 transitions, illustrated the importance of including n=3 and 4 levels in the calculations compared to previous work. (K. Butler and C. Mendoza, Mon. Not. R. Astr. Soc. 208), 17 (1984). Particular emphasis is now placed on transitions to the intercombination 2s^22p^3[^4S^o]3s ^3,5S^o levels and to the other n=3 levels where comparison can be made with previous distorted-wave work. The calculations of fine-structure transitions by electron impact, to and within these multiplets of NeIII provide much needed accurate data for astrophysical models. Further details and a comprehensive set of results will be presented at the meeting.

  20. Electron impact ionisation cross sections of iron oxides

    NASA Astrophysics Data System (ADS)

    Huber, Stefan E.; Mauracher, Andreas; Sukuba, Ivan; Urban, Jan; Maihom, Thana; Probst, Michael

    2017-12-01

    We report electron impact ionisation cross sections (EICSs) of iron oxide molecules, FexOx and FexOx+1 with x = 1, 2, 3, from the ionisation threshold to 10 keV, obtained with the Deutsch-Märk (DM) and binary-encounter-Bethe (BEB) methods. The maxima of the EICSs range from 3.10 to 9 . 96 × 10-16 cm2 located at 59-72 eV and 5.06 to 14.32 × 10-16 cm2 located at 85-108 eV for the DM and BEB approaches, respectively. The orbital and kinetic energies required for the BEB method are obtained by employing effective core potentials for the inner core electrons in the quantum chemical calculations. The BEB cross sections are 1.4-1.7 times larger than the DM cross sections which can be related to the decreasing population of the Fe 4s orbitals upon addition of oxygen atoms, together with the different methodological foundations of the two methods. Both the DM and BEB cross sections can be fitted excellently to a simple analytical expression used in modelling and simulation codes employed in the framework of nuclear fusion research. Supplementary material in the form of one pdf file available from the Journal web page at http://https://doi.org/10.1140/epjd/e2017-80308-2.

  1. Role of electronic excited N2 in vibrational excitation of the N2 ground state at high latitudes

    NASA Astrophysics Data System (ADS)

    Campbell, L.; Cartwright, D. C.; Brunger, M. J.; Teubner, P. J. O.

    2006-09-01

    Vibrationally excited N2 is important in determining the ionospheric electron density and has also been proposed to play a role in the production of NO in disturbed atmospheres. We report here predictions of the absolute vibrational distributions in the ground electronic state of N2 produced by electron impact excitation, at noon and midnight under quiet geomagnetic conditions and disturbed conditions corresponding to the aurora IBCII+ and IBCIII+ at 60°N latitude and 0° longitude, at altitudes between 130 and 350 km. These predictions were obtained from a model which includes thermal excitation and direct electron impact excitation of the vibrational levels of the N2 ground state and its excited electronic states; radiative cascade from all excited electronic states to all vibrational levels of the ground electronic state; quenching by O, O2, and N2; molecular and ambipolar diffusion; and the dominant chemical reactions. Results from this study show that for both aurora and daytime electron environments: (1) cascade from the higher electronic states of N2 determines the population of the higher vibrational levels in the N2 ground state and (2) the effective ground state vibrational temperature for levels greater than 4 in N2 is predicted to be in the range 4000-13000 K for altitudes greater than 200 km. Correspondingly, the associated enhancement factor for the O+ reaction with vibrationally excited N2 to produce NO+ is predicted to increase with increasing altitude (up to a maximum at a height which increases with auroral strength) for both aurora and daytime environments and to increase with increasing auroral strength. The contribution of the cascade from the excited electronic states was evaluated and found to be relatively minor compared to the direct excitation process.

  2. Electron line shape and transmission function of the KATRIN monitor spectrometer

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Slezák, M.

    Knowledge of the neutrino mass is of particular interest in modern neutrino physics. Besides the neutrinoless double beta decay and cosmological observation information about the neutrino mass is obtained from single beta decay by observing the shape of the electron spectrum near the endpoint. The KATRIN β decay experiment aims to push the limit on the effective electron antineutrino mass down to 0.2 eV/c{sup 2}. To reach this sensitivity several systematic effects have to be under control. One of them is the fluctuations of the absolute energy scale, which therefore has to be continuously monitored at very high precision. Thismore » paper shortly describes KATRIN, the technique for continuous monitoring of the absolute energy scale and recent improvements in analysis of the monitoring data.« less

  3. Pulling Marbles from a Bag: Deducing the Regional Impact History of the SPA Basin from Impact-Melt Rocks

    NASA Technical Reports Server (NTRS)

    Cohen, Barbara A.; Coker, Robert F.

    2010-01-01

    The South Pole Aitken (SPA) basin is the stratigraphically oldest identifiable lunar basin and is therefore one of the most important targets for absolute age-dating to help understand whether ancient lunar bombardment history smoothly declined or was punctuated by a cataclysm. A feasible near-term approach to this problem is to robotically collect a sample from near the center of the basin, where vertical and lateral mixing provided by post-basin impacts ensures that such a sample will be composed of small rock fragments from SPA itself, from local impact craters, and from faraway giant basins. The range of ages, intermediate spikes in the age distribution, and the oldest ages are all part of the definition of the absolute age and impact history recorded within the SPA basin.

  4. Microwave zero-resistance states in a bilayer electron system.

    PubMed

    Wiedmann, S; Gusev, G M; Raichev, O E; Bakarov, A K; Portal, J C

    2010-07-09

    Magnetotransport measurements on a high-mobility electron bilayer system formed in a wide GaAs quantum well reveal vanishing dissipative resistance under continuous microwave irradiation. Profound zero-resistance states (ZRS) appear even in the presence of additional intersubband scattering of electrons. We study the dependence of photoresistance on frequency, microwave power, and temperature. Experimental results are compared with a theory demonstrating that the conditions for absolute negative resistivity correlate with the appearance of ZRS.

  5. Vanadium fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser–solid experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Palmeri, P., E-mail: patrick.palmeri@umons.ac.be; Quinet, P., E-mail: pascal.quinet@umons.ac.be; IPNAS, Université de Liège, B-4000 Liège

    2015-09-15

    The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser–solid experiments through the K-shell emission cross section. In addition, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al. (2012)), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the vanadium isonuclear ions have been calculated. In this study, the K-shell EII cross sections connecting the ground and the metastable levels of the parent vanadium ions to the daughter ions K-vacancy levels considered in Palmerimore » et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 20 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic behavior of the modified relativistic binary encounter Bethe model (MRBEB) of Guerra et al. (2012) with the density-effect correction proposed by Davies et al. (2013)« less

  6. Specific climate impact of passenger and freight transport

    DOT National Transportation Integrated Search

    2010-01-01

    Emissions of short-lived species contribute significantly to : the climate impact of transportation. The magnitude of the effects : varies over time for each transport mode. This paper compares : first the absolute climate impacts of current passenge...

  7. Brightness measurement of an electron impact gas ion source for proton beam writing applications

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Liu, N.; Santhana Raman, P.; Department of Electrical and Computer Engineering, National University of Singapore, Singapore 117583

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness thatmore » is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.« less

  8. Brightness measurement of an electron impact gas ion source for proton beam writing applications.

    PubMed

    Liu, N; Xu, X; Pang, R; Raman, P Santhana; Khursheed, A; van Kan, J A

    2016-02-01

    We are developing a high brightness nano-aperture electron impact gas ion source, which can create ion beams from a miniature ionization chamber with relatively small virtual source sizes, typically around 100 nm. A prototype source of this kind was designed and successively micro-fabricated using integrated circuit technology. Experiments to measure source brightness were performed inside a field emission scanning electron microscope. The total output current was measured to be between 200 and 300 pA. The highest estimated reduced brightness was found to be comparable to the injecting focused electron beam reduced brightness. This translates into an ion reduced brightness that is significantly better than that of conventional radio frequency ion sources, currently used in single-ended MeV accelerators.

  9. Structural identification of triacylglycerol isomers using electron impact excitation of ions from organics (EIEIO).

    PubMed

    Baba, Takashi; Campbell, J Larry; Le Blanc, J C Yves; Baker, Paul R S

    2016-11-01

    Electron-induced dissociation or electron impact excitation of ions from organics (EIEIO) was applied to triacylglycerols (TAGs) for in-depth molecular structure analysis using MS. In EIEIO, energetic electrons (∼10 eV) fragmented TAG ions to allow for regioisomeric assignment of identified acyl groups at the sn-2 or sn-1/3 positions of the glycerol backbone. In addition, carbon-carbon double bond locations within the acyl chains could also be assigned by EIEIO. Beyond the analysis of lipid standards, this technique was applied to edible oils and natural lipid extracts to demonstrate the power of this method to provide in-depth structural elucidation of TAG molecular species. Copyright © 2016 by the American Society for Biochemistry and Molecular Biology, Inc.

  10. Electron-impact excitation of diatomic hydride cations - I. HeH+, CH+, ArH+

    NASA Astrophysics Data System (ADS)

    Hamilton, James R.; Faure, Alexandre; Tennyson, Jonathan

    2016-01-01

    R-matrix calculations combined with the adiabatic nuclei approximation are used to compute electron-impact rotational excitation rates for three closed-shell diatomic cations, HeH+, CH+, ArH+. Comparisons with previous studies show that an improved treatment of threshold effects leads to significant changes in the low temperature rates; furthermore the new calculations suggest that excitation of CH+ is dominated by ΔJ = 1 transitions as is expected for cations with a large dipole moment. A model for ArH+ excitation in the Crab nebula is presented which gives results consistent with the observations for electron densities in the range 2-3 × 103 cm-3.

  11. Non-contact temperature measurement requirements for electronic materials processing

    NASA Technical Reports Server (NTRS)

    Lehoczky, S. L.; Szofran, F. R.

    1988-01-01

    The requirements for non-contact temperature measurement capabilities for electronic materials processing in space are assessed. Non-contact methods are probably incapable of sufficient accuracy for the actual absolute measurement of temperatures in most such applications but would be useful for imaging in some applications.

  12. Measurements of the absolute energy spectra of cosmic-ray positrons and electrons above 7 GeV

    NASA Astrophysics Data System (ADS)

    Grimani, C.; Stephens, S. A.; Cafagna, F. S.; Basini, G.; Bellotti, R.; Brunetti, M. T.; Circella, M.; Codino, A.; De Marzo, C.; De Pascale, M. P.; Finetti, N.; Golden, R. L.; Hof, M.; Menn, W.; Mitchell, J. W.; Morselli, A.; Ormes, J. F.; Papini, P.; Pfeifer, C.; Piccardi, S.; Picozza, P.; Ricci, M.; Simon, M.; Spillantini, P.; Stochaj, S. J.; Streitmatter, R. E.

    2002-09-01

    A measurement of the energy spectra of cosmic-ray positrons and electrons was made with a balloon-borne magnet-spectrometer, which was flown at a mean geomagnetic cut-off of 4.5 GV/c. The observed positron flux in the energy range 7-16 GeV is approximately an order of magnitude lower than that of electrons, as measured in other experiments at various energies. The power law spectral index of the observed differential energy spectrum of electrons is -2.89 +/- 0.10 in the energy interval 7.5-47 GeV. For positrons the overall fit of the available data above 7 GeV has been considered. The spectral index is found to be -3.37 +/- 0.26 and the fraction of positrons, e+/(e+,+ e-), has a mean value of 0.064 +/- 0.003. The world data on e+/(e+,+ e-) from 0.1 to 30 GeV indicate that a plerion type electron spectrum is preferred over the other types. The trend of the presently existing high energy data also suggests a possible contribution of positrons produced at the pulsar polar cap. High resolution experiments capable of identifying positrons at least up to 100 GeV with high statistics are required to pinpoint the origin of both electrons and positrons in the cosmic radiation.

  13. NIST Stars: Absolute Spectrophotometric Calibration of Vega and Sirius

    NASA Astrophysics Data System (ADS)

    Deustua, Susana; Woodward, John T.; Rice, Joseph P.; Brown, Steven W.; Maxwell, Stephen E.; Alberding, Brian G.; Lykke, Keith R.

    2018-01-01

    Absolute flux calibration of standard stars, traceable to SI (International System of Units) standards, is essential for 21st century astrophysics. Dark energy investigations that rely on observations of Type Ia supernovae and precise photometric redshifts of weakly lensed galaxies require a minimum accuracy of 0.5 % in the absolute color calibration. Studies that aim to address fundamental stellar astrophysics also benefit. In the era of large telescopes and all sky surveys well-calibrated standard stars that do not saturate and that are available over the whole sky are needed. Significant effort has been expended to obtain absolute measurements of the fundamental standards Vega and Sirius (and other stars) in the visible and near infrared, achieving total uncertainties between1% and 3%, depending on wavelength, that do not meet the needed accuracy. The NIST Stars program aims to determine the top-of-the-atmosphere absolute spectral irradiance of bright stars to an uncertainty less than 1% from a ground-based observatory. NIST Stars has developed a novel, fully SI-traceable laboratory calibration strategy that will enable achieving the desired accuracy. This strategy has two key components. The first is the SI-traceable calibration of the entire instrument system, and the second is the repeated spectroscopic measurement of the target star throughout the night. We will describe our experimental strategy, present preliminary results for Vega and Sirius and an end-to-end uncertainty budget

  14. An Integrated Model of Choices and Response Times in Absolute Identification

    ERIC Educational Resources Information Center

    Brown, Scott D.; Marley, A. A. J.; Donkin, Christopher; Heathcote, Andrew

    2008-01-01

    Recent theoretical developments in the field of absolute identification have stressed differences between relative and absolute processes, that is, whether stimulus magnitudes are judged relative to a shorter term context provided by recently presented stimuli or a longer term context provided by the entire set of stimuli. The authors developed a…

  15. Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Fujihashi, Yuta; Ishizaki, Akihito, E-mail: ishizaki@ims.ac.jp; Fleming, Graham R.

    2015-06-07

    Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. In this work, we address a dimer which produces little beating of electronic origin in the absence ofmore » vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.« less

  16. Impact of environmentally induced fluctuations on quantum mechanically mixed electronic and vibrational pigment states in photosynthetic energy transfer and 2D electronic spectra

    DOE PAGES

    Fujihashi, Yuta; Fleming, Graham R.; Ishizaki, Akihito

    2015-03-11

    Recently, nuclear vibrational contribution signatures in two-dimensional (2D) electronic spectroscopy have attracted considerable interest, in particular as regards interpretation of the oscillatory transients observed in light-harvesting complexes. These transients have dephasing times that persist for much longer than theoretically predicted electronic coherence lifetime. As a plausible explanation for this long-lived spectral beating in 2D electronic spectra, quantum-mechanically mixed electronic and vibrational states (vibronic excitons) were proposed by Christensson et al. [J. Phys. Chem. B 116, 7449 (2012)] and have since been explored. Here in this work, we address a dimer which produces little beating of electronic origin in the absencemore » of vibronic contributions, and examine the impact of protein-induced fluctuations upon electronic-vibrational quantum mixtures by calculating the electronic energy transfer dynamics and 2D electronic spectra in a numerically accurate manner. It is found that, at cryogenic temperatures, the electronic-vibrational quantum mixtures are rather robust, even under the influence of the fluctuations and despite the small Huang-Rhys factors of the Franck-Condon active vibrational modes. This results in long-lasting beating behavior of vibrational origin in the 2D electronic spectra. At physiological temperatures, however, the fluctuations eradicate the mixing, and hence, the beating in the 2D spectra disappears. Further, it is demonstrated that such electronic-vibrational quantum mixtures do not necessarily play a significant role in electronic energy transfer dynamics, despite contributing to the enhancement of long-lived quantum beating in 2D electronic spectra, contrary to speculations in recent publications.« less

  17. Electron-Impact Excitation Cross Sections for Modeling Non-Equilibrium Gas

    NASA Technical Reports Server (NTRS)

    Huo, Winifred M.; Liu, Yen; Panesi, Marco; Munafo, Alessandro; Wray, Alan; Carbon, Duane F.

    2015-01-01

    In order to provide a database for modeling hypersonic entry in a partially ionized gas under non-equilibrium, the electron-impact excitation cross sections of atoms have been calculated using perturbation theory. The energy levels covered in the calculation are retrieved from the level list in the HyperRad code. The downstream flow-field is determined by solving a set of continuity equations for each component. The individual structure of each energy level is included. These equations are then complemented by the Euler system of equations. Finally, the radiation field is modeled by solving the radiative transfer equation.

  18. Absolute branching fraction measurements of exclusive D0 semileptonic decays.

    PubMed

    Coan, T E; Gao, Y S; Liu, F; Artuso, M; Boulahouache, C; Blusk, S; Butt, J; Dambasuren, E; Dorjkhaidav, O; Li, J; Menaa, N; Mountain, R; Nandakumar, R; Redjimi, R; Sia, R; Skwarnicki, T; Stone, S; Wang, J C; Zhang, K; Csorna, S E; Bonvicini, G; Cinabro, D; Dubrovin, M; Briere, R A; Chen, G P; Chen, J; Ferguson, T; Tatishvili, G; Vogel, H; Watkins, M E; Rosner, J L; Adam, N E; Alexander, J P; Berkelman, K; Cassel, D G; Crede, V; Duboscq, J E; Ecklund, K M; Ehrlich, R; Fields, L; Gibbons, L; Gittelman, B; Gray, R; Gray, S W; Hartill, D L; Heltsley, B K; Hertz, D; Hsu, L; Jones, C D; Kandaswamy, J; Kreinick, D L; Kuznetsov, V E; Mahlke-Krüger, H; Meyer, T O; Onyisi, P U E; Patterson, J R; Peterson, D; Pivarski, J; Phillips, E A; Riley, D; Ryd, A; Sadoff, A J; Schwarthoff, H; Shepherd, M R; Stroiney, S; Sun, W M; Urner, D; Wilksen, T; Weinberger, M; Athar, S B; Avery, P; Breva-Newell, L; Patel, R; Potlia, V; Stoeck, H; Yelton, J; Rubin, P; Cawlfield, C; Eisenstein, B I; Gollin, G D; Karliner, I; Kim, D; Lowrey, N; Naik, P; Sedlack, C; Selen, M; Williams, J; Wiss, J; Edwards, K W; Besson, D; Pedlar, T K; Cronin-Hennessy, D; Gao, K Y; Gong, D T; Kubota, Y; Klein, T; Lang, B W; Li, S Z; Poling, R; Scott, A W; Smith, A; Dobbs, S; Metreveli, Z; Seth, K K; Tomaradze, A; Zweber, P; Ernst, J; Mahmood, A H; Severini, H; Asner, D M; Dytman, S A; Love, W; Mehrabyan, S; Mueller, J A; Savinov, V; Li, Z; Lopez, A; Mendez, H; Ramirez, J; Huang, G S; Miller, D H; Pavlunin, V; Sanghi, B; Shibata, E I; Shipsey, I P J; Adams, G S; Chasse, M; Cravey, M; Cummings, J P; Danko, I; Napolitano, J; He, Q; Muramatsu, H; Park, C S; Park, W; Thorndike, E H

    2005-10-28

    With the first data sample collected by the CLEO-c detector at the psi(3770) resonance we have studied four exclusive semileptonic decays of the D0 meson. Our results include the first observation and absolute branching fraction measurement for D0 --> p-e+ve and improved measurements of the absolute branching fractions for D0 decays to K-e+ve, pi-e+ve, and K*-e+ve.

  19. Improvements in absolute seismometer sensitivity calibration using local earth gravity measurements

    USGS Publications Warehouse

    Anthony, Robert E.; Ringler, Adam; Wilson, David

    2018-01-01

    The ability to determine both absolute and relative seismic amplitudes is fundamentally limited by the accuracy and precision with which scientists are able to calibrate seismometer sensitivities and characterize their response. Currently, across the Global Seismic Network (GSN), errors in midband sensitivity exceed 3% at the 95% confidence interval and are the least‐constrained response parameter in seismic recording systems. We explore a new methodology utilizing precise absolute Earth gravity measurements to determine the midband sensitivity of seismic instruments. We first determine the absolute sensitivity of Kinemetrics EpiSensor accelerometers to 0.06% at the 99% confidence interval by inverting them in a known gravity field at the Albuquerque Seismological Laboratory (ASL). After the accelerometer is calibrated, we install it in its normal configuration next to broadband seismometers and subject the sensors to identical ground motions to perform relative calibrations of the broadband sensors. Using this technique, we are able to determine the absolute midband sensitivity of the vertical components of Nanometrics Trillium Compact seismometers to within 0.11% and Streckeisen STS‐2 seismometers to within 0.14% at the 99% confidence interval. The technique enables absolute calibrations from first principles that are traceable to National Institute of Standards and Technology (NIST) measurements while providing nearly an order of magnitude more precision than step‐table calibrations.

  20. Absolute photoionization cross-section of the methyl radical.

    PubMed

    Taatjes, Craig A; Osborn, David L; Selby, Talitha M; Meloni, Giovanni; Fan, Haiyan; Pratt, Stephen T

    2008-10-02

    The absolute photoionization cross-section of the methyl radical has been measured using two completely independent methods. The CH3 photoionization cross-section was determined relative to that of acetone and methyl vinyl ketone at photon energies of 10.2 and 11.0 eV by using a pulsed laser-photolysis/time-resolved synchrotron photoionization mass spectrometry method. The time-resolved depletion of the acetone or methyl vinyl ketone precursor and the production of methyl radicals following 193 nm photolysis are monitored simultaneously by using time-resolved synchrotron photoionization mass spectrometry. Comparison of the initial methyl signal with the decrease in precursor signal, in combination with previously measured absolute photoionization cross-sections of the precursors, yields the absolute photoionization cross-section of the methyl radical; sigma(CH3)(10.2 eV) = (5.7 +/- 0.9) x 10(-18) cm(2) and sigma(CH3)(11.0 eV) = (6.0 +/- 2.0) x 10(-18) cm(2). The photoionization cross-section for vinyl radical determined by photolysis of methyl vinyl ketone is in good agreement with previous measurements. The methyl radical photoionization cross-section was also independently measured relative to that of the iodine atom by comparison of ionization signals from CH3 and I fragments following 266 nm photolysis of methyl iodide in a molecular-beam ion-imaging apparatus. These measurements gave a cross-section of (5.4 +/- 2.0) x 10(-18) cm(2) at 10.460 eV, (5.5 +/- 2.0) x 10(-18) cm(2) at 10.466 eV, and (4.9 +/- 2.0) x 10(-18) cm(2) at 10.471 eV. The measurements allow relative photoionization efficiency spectra of methyl radical to be placed on an absolute scale and will facilitate quantitative measurements of methyl concentrations by photoionization mass spectrometry.

  1. Absolute Stability Analysis of a Phase Plane Controlled Spacecraft

    NASA Technical Reports Server (NTRS)

    Jang, Jiann-Woei; Plummer, Michael; Bedrossian, Nazareth; Hall, Charles; Jackson, Mark; Spanos, Pol

    2010-01-01

    Many aerospace attitude control systems utilize phase plane control schemes that include nonlinear elements such as dead zone and ideal relay. To evaluate phase plane control robustness, stability margin prediction methods must be developed. Absolute stability is extended to predict stability margins and to define an abort condition. A constrained optimization approach is also used to design flex filters for roll control. The design goal is to optimize vehicle tracking performance while maintaining adequate stability margins. Absolute stability is shown to provide satisfactory stability constraints for the optimization.

  2. Single electron impact ionization of the methane molecule

    NASA Astrophysics Data System (ADS)

    Bouamoud, Mammar; Sahlaoui, Mohammed; Benmansour, Nour El Houda; Atomic and Molecular Collisions Team

    2014-10-01

    Triply differential cross sections (TDCS) results of electron-impact ionization of the inner 2a1 molecular orbital of CH4 are presented in the framework of the Second Born Approximation and compared with the experimental data performed in coplanar asymmetric geometry. The cross sections are averaged on the random orientations of the molecular target for accurate comparison with experiments and are compared also with the theoretical calculations of the Three Coulomb wave (3CW) model. Our results are in good agreement with experiments and 3CW results in the binary peak. In contrast the Second Born Approximation yields a significant higher values compared to the 3CW results for the recoil peak and seems to describe suitably the recoil region where higher order effects can occur with the participation of the recoiling ion in the collision process.

  3. How and How Much Molecular Conformation Affects Electronic Circular Dichroism: The Case of 1,1-Diarylcarbinols.

    PubMed

    Padula, Daniele; Pescitelli, Gennaro

    2018-01-09

    Chiroptical spectra such as electronic circular dichroism (ECD) are said to be much more sensitive to conformation than their non-chiroptical counterparts, however, it is difficult to demonstrate such a common notion in a clear-cut way. We run DFT and TDDFT calculations on two closely related 1,1-diarylmethanols which show mirror-image ECD spectra for the same absolute configuration. We demonstrate that the main reason for the different chiroptical response of the two compounds lies in different conformational ensembles, caused by a single hydrogen-to-methyl substitution. We conclude that two compounds, having the same configuration but different conformation, may exhibit mirror-image ECD signals, stressing the importance and impact of conformational factors on ECD spectra.

  4. Observation of fast and slow interatomic Coulombic decay in argon dimers induced by electron-impact ionization

    NASA Astrophysics Data System (ADS)

    Ren, Xueguang; Miteva, Tsveta; Kolorenč, Přemysl; Gokhberg, Kirill; Kuleff, Alexander I.; Cederbaum, Lorenz S.; Dorn, Alexander

    2017-09-01

    We investigate the interatomic Coulombic decay (ICD) in argon dimers induced by electron-impact ionization (E0=90 eV ) using a multiparticle coincidence experiment in which the momentum vectors and, consequently, the kinetic energies for electrons and fragment ions are determined. The signature of the ICD process is obtained from a correlation map between ejected electron energy and kinetic energy release (KER) for Ar++Ar+ fragment ions where low-energy ICD electrons can be identified. Furthermore, two types of ICD processes, termed fast and slow interatomic decay, are separated by the ICD initial-state energies and projectile energy losses. The dependence of the energies of emitted low-energy ICD electrons on the initial-state energy is studied. ICD electron energy spectra and KER spectra are obtained separately for fast and slow decay processes where the KER spectra for the slow decay channel are strongly influenced by nuclear motion. The KER and ICD electron energy spectra are well reproduced by ab initio calculations.

  5. The impact of electronic health record use on physician productivity.

    PubMed

    Adler-Milstein, Julia; Huckman, Robert S

    2013-11-01

    To examine the impact of the degree of electronic health record (EHR) use and delegation of EHR tasks on clinician productivity in ambulatory settings. We examined EHR use in primary care practices that implemented a web-based EHR from athenahealth (n = 42) over 3 years (695 practice-month observations). Practices were predominantly small and spread throughout the country. Data came from athenahealth practice management system and EHR task logs. We developed monthly measures of EHR use and delegation to support staff from task logs. Productivity was measured using work relative value units (RVUs). Using fixed effects models, we assessed the independent impacts on productivity of EHR use and delegation. We then explored the interaction between these 2 strategies and the role of practice size. Greater EHR use and greater delegation were independently associated with higher levels of productivity. An increase in EHR use of 1 standard deviation resulted in a 5.3% increase in RVUs per clinician workday; an increase in delegation of EHR tasks of 1 standard deviation resulted in an 11.0% increase in RVUs per clinician workday (P <.05 for both). Further, EHR use and delegation had a positive joint impact on productivity in large practices (coefficient, 0.058; P <.05), but a negative joint impact on productivity in small practices (coefficient, -0.142; P <.01). Clinicians in practices that increased EHR use and delegated EHR tasks were more productive, but practice size determined whether the 2 strategies were complements or substitutes.

  6. Absolute Points for Multiple Assignment Problems

    ERIC Educational Resources Information Center

    Adlakha, V.; Kowalski, K.

    2006-01-01

    An algorithm is presented to solve multiple assignment problems in which a cost is incurred only when an assignment is made at a given cell. The proposed method recursively searches for single/group absolute points to identify cells that must be loaded in any optimal solution. Unlike other methods, the first solution is the optimal solution. The…

  7. The PMA Catalogue: 420 million positions and absolute proper motions

    NASA Astrophysics Data System (ADS)

    Akhmetov, V. S.; Fedorov, P. N.; Velichko, A. B.; Shulga, V. M.

    2017-07-01

    We present a catalogue that contains about 420 million absolute proper motions of stars. It was derived from the combination of positions from Gaia DR1 and 2MASS, with a mean difference of epochs of about 15 yr. Most of the systematic zonal errors inherent in the 2MASS Catalogue were eliminated before deriving the absolute proper motions. The absolute calibration procedure (zero-pointing of the proper motions) was carried out using about 1.6 million positions of extragalactic sources. The mean formal error of the absolute calibration is less than 0.35 mas yr-1. The derived proper motions cover the whole celestial sphere without gaps for a range of stellar magnitudes from 8 to 21 mag. In the sky areas where the extragalactic sources are invisible (the avoidance zone), a dedicated procedure was used that transforms the relative proper motions into absolute ones. The rms error of proper motions depends on stellar magnitude and ranges from 2-5 mas yr-1 for stars with 10 mag < G < 17 mag to 5-10 mas yr-1 for faint ones. The present catalogue contains the Gaia DR1 positions of stars for the J2015 epoch. The system of the PMA proper motions does not depend on the systematic errors of the 2MASS positions, and in the range from 14 to 21 mag represents an independent realization of a quasi-inertial reference frame in the optical and near-infrared wavelength range. The Catalogue also contains stellar magnitudes taken from the Gaia DR1 and 2MASS catalogues. A comparison of the PMA proper motions of stars with similar data from certain recent catalogues has been undertaken.

  8. Ross filter development for absolute measurement of Al line radiation on MST

    NASA Astrophysics Data System (ADS)

    Lauersdorf, N.; Reusch, L. M.; den Hartog, D. J.; Goetz, J. A.; Franz, P.; Vanmeter, P.

    2017-10-01

    The MST has a two-color soft x-ray tomography (SXT) diagnostic that, using the double-filter technique, measures electron temperature (Te) from the slope of the soft x-ray (SXR) continuum. Because MST has an aluminum plasma-facing surface, bright Al line radiation occurs in the SXR spectrum. In past application of the double-filter technique, these lines have been filtered out using thick Be filters ( 400 μm and 800 μm), restricting the measurement temperature range to >=1 keV due to the signal strength having a positive correlation with Te. Another way to deal with the line radiation is to explicitly include it into the SXR spectrum analysis from which Te is derived. A Ross filter set has been designed to measure this line radiation, and will enable the absolute intensities of the aluminum lines to be quantified and incorporated into the analysis. The Ross filter will be used to measure Al+11 and Al+12 lines, occurring between 1.59 and 2.04 keV. By using multiple detectors with filters made of varying element concentrations, we create spectral bins in which the dominant transmission is the line radiation. Absolute measurement of Al line intensities will enable use of thinner filters in the SXT diagnostic and accurate measurement of Te < 1 keV. This material is based upon work supported by the U.S. Department of Energy Office of Science, Office of Fusion Energy Sciences program under Award Numbers DE-FC02-05ER54814 and DE-SC0015474.

  9. Development and validation of a cerebral oximeter capable of absolute accuracy.

    PubMed

    MacLeod, David B; Ikeda, Keita; Vacchiano, Charles; Lobbestael, Aaron; Wahr, Joyce A; Shaw, Andrew D

    2012-12-01

    Cerebral oximetry may be a valuable monitor, but few validation data are available, and most report the change from baseline rather than absolute accuracy, which may be affected by individuals whose oximetric values are outside the expected range. The authors sought to develop and validate a cerebral oximeter capable of absolute accuracy. An in vivo research study. A university human physiology laboratory. Healthy human volunteers were enrolled in calibration and validation studies of 2 cerebral oximetric sensors, the Nonin 8000CA and 8004CA. The 8000CA validation study identified 5 individuals with atypical cerebral oxygenation values; their data were used to design the 8004CA sensor, which subsequently underwent calibration and validation. Volunteers were taken through a stepwise hypoxia protocol to a minimum saturation of peripheral oxygen. Arteriovenous saturation (70% jugular bulb venous saturation and 30% arterial saturation) at 6 hypoxic plateaus was used as the reference value for the cerebral oximeter. Absolute accuracy was defined using a combination of the bias and precision of the paired saturations (A(RMS)). In the validation study for the 8000CA sensor (n = 9, 106 plateaus), relative accuracy was an A(RMS) of 2.7, with an absolute accuracy of 8.1, meeting the criteria for a relative (trend) monitor, but not an absolute monitor. In the validation study for the 8004CA sensor (n = 11, 119 plateaus), the A(RMS) of the 8004CA was 4.1, meeting the prespecified success criterion of <5.0. The Nonin cerebral oximeter using the 8004CA sensor can provide absolute data on regional cerebral saturation compared with arteriovenous saturation, even in subjects previously shown to have values outside the normal population distribution curves. Copyright © 2012 Elsevier Inc. All rights reserved.

  10. Determination of the absolute configurations of natural products via density functional theory calculations of optical rotation, electronic circular dichroism, and vibrational circular dichroism: the cytotoxic sesquiterpene natural products quadrone, suberosenone, suberosanone, and suberosenol A acetate.

    PubMed

    Stephens, P J; McCann, D M; Devlin, F J; Smith, A B

    2006-07-01

    The determination of the absolute configurations (ACs) of chiral molecules using the chiroptical techniques of optical rotation (OR), electronic circular dichroism (ECD), and vibrational circular dichroism (VCD) has been revolutionized by the development of density functional theory (DFT) methods for the prediction of these properties. Here, we demonstrate the significance of these advances for the stereochemical characterization of natural products. Time-dependent DFT (TDDFT) calculations of the specific rotations, [alpha](D), of four cytotoxic natural products, quadrone (1), suberosenone (2), suberosanone (3), and suberosenol A acetate (4), are used to assign their ACs. TDDFT calculations of the ECD of 1 are used to assign its AC. The VCD spectrum of 1 is reported and also used, together with DFT calculations, to assign its AC. The ACs of 1 derived from its [alpha](D), ECD, and VCD are identical and in agreement with the AC previously determined via total synthesis. The previously undetermined ACs of 2-4, derived from their [alpha](D) values, have absolute configurations of their tricyclic cores identical to that of 1. Further studies of the ACs of these molecules using ECD and, especially, VCD are recommended to establish more definitively this finding. Our studies of the OR, ECD, and VCD of quadrone are the first to utilize DFT calculations of all three properties for the determination of the AC of a chiral natural product molecule.

  11. Use of the Bethe equation for inner-shell ionization by electron impact

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Powell, Cedric J.; Llovet, Xavier; Salvat, Francesc

    2016-05-14

    We analyzed calculated cross sections for K-, L-, and M-shell ionization by electron impact to determine the energy ranges over which these cross sections are consistent with the Bethe equation for inner-shell ionization. Our analysis was performed with K-shell ionization cross sections for 26 elements, with L-shell ionization cross sections for seven elements, L{sub 3}-subshell ionization cross sections for Xe, and M-shell ionization cross sections for three elements. The validity (or otherwise) of the Bethe equation could be checked with Fano plots based on a linearized form of the Bethe equation. Our Fano plots, which display theoretical cross sections andmore » available measured cross sections, reveal two linear regions as predicted by de Heer and Inokuti [in Electron Impact Ionization, edited by T. D. Märk and G. H. Dunn, (Springer-Verlag, Vienna, 1985), Chap. 7, pp. 232–276]. For each region, we made linear fits and determined values of the two element-specific Bethe parameters. We found systematic variations of these parameters with atomic number for both the low- and the high-energy linear regions of the Fano plots. We also determined the energy ranges over which the Bethe equation can be used.« less

  12. Electron impact fragmentation of thymine: partial ionization cross sections for positive fragments

    NASA Astrophysics Data System (ADS)

    van der Burgt, Peter J. M.; Mahon, Francis; Barrett, Gerard; Gradziel, Marcin L.

    2014-06-01

    We have measured mass spectra for positive ions for low-energy electron impact on thymine using a reflectron time-of-flight mass spectrometer. Using computer controlled data acquisition, mass spectra have been acquired for electron impact energies up to 100 eV in steps of 0.5 eV. Ion yield curves for most of the fragment ions have been determined by fitting groups of adjacent peaks in the mass spectra with sequences of normalized Gaussians. The ion yield curves have been normalized by comparing the sum of the ion yields to the average of calculated total ionization cross sections. Appearance energies have been determined. The nearly equal appearance energies of 83 u and 55 u observed in the present work strongly indicate that near threshold the 55 u ion is formed directly by the breakage of two bonds in the ring, rather than from a successive loss of HNCO and CO from the parent ion. Likewise 54 u is not formed by CO loss from 82 u. The appearance energies are in a number of cases consistent with the loss of one or more hydrogen atoms from a heavier fragment, but 70 u is not formed by hydrogen loss from 71 u.

  13. [The impact of electronic cigarettes usage on the endothelial function and the progression of atherosclerosis].

    PubMed

    Knura, Miłosz; Dragon, Jonasz; Łabuzek, Krzysztof; Okopień, Bogusław

    2018-01-23

    The exponetial growth in popularity of electronic cigarettes in the world markets intensifies the debate about their health effects. The smoking of traditional tabacoo products is a factor associated with the endothelium damage and progression of atherosclerosis. The elimination of the combustion process in electronic cigarettes allows to conclude that they are less harmful to a vascular endothelium than traditional tobacco products. E-cigarette aerosol contains many compounds that have an influence on initiation and progression of atherosclerosis. Nicotine protherogenic action is not fully explained. On one hand, nicotine modifies metabolic pathways leading to atherosclerosis, whereas epidemiological studies do not show an increased risk of cardiovascular disease in the population using nicotine replacement therapy or snuff. Acrolein, formaldehyde and the ultrafine particles generated during e-liquid heating have an impact on initiation and progression of atherosclerosis, but their level is lower than that of tobacco smoke. In order to assess accurately the longterm effects of e-cigarettes, it is necessary to conduct epidemiological studies measuring the effects of using e-cigarettes. It is claimed that the use of electronic cigarettes has a potential impact on the development of atherosclerosis, but is significantly lower than that of traditional cigarettes.

  14. Prognostic roles of absolute monocyte and absolute lymphocyte counts in patients with advanced-stage follicular lymphoma in the rituximab era: an analysis from the FOLL05 trial of the Fondazione Italiana Linfomi.

    PubMed

    Marcheselli, Luigi; Bari, Alessia; Anastasia, Antonella; Botto, Barbara; Puccini, Benedetta; Dondi, Alessandra; Carella, Angelo M; Alvarez, Isabel; Chiarenza, Annalisa; Arcari, Annalisa; Salvi, Flavia; Federico, Massimo

    2015-05-01

    Recently, in an attempt to improve the discrimination power of the international prognostic index (IPI), patients with diffuse large B-cell lymphoma were evaluated to determine the prognostic roles of peripheral blood absolute monocyte count (AMC) and absolute lymphocyte count (ALC). Here, we analysed data of 428 patients with follicular lymphoma (FL) enrolled in a prospective, randomized trial (FOLL05 study) conducted by Fondazione Italiana Linfomi, to assess the impact of AMC and ALC on progression-free survival (PFS). All patients had been treated with one of three treatment combinations: (i) rituximab (R) plus cyclophosphamide, vincristine and prednisone; (ii) R plus cyclophosphamide, doxorubicin, vincristine and prednisone or (iii) R plus mitoxantrone and fludarabine. We showed that only AMC was a powerful predictor of PFS, and possibly overall survival, in patients with FL treated with combination chemotherapy regimens that contained R. The AMC can be used alone as a novel, simple factor that can predict survival outcome in patients with FL, independent of the immunochemotherapy regimen. It may therefore be widely used by clinicians, due to its simplicity and broad applicability. Additionally, it can be combined with other factors that determine the IPI or FLIPI, to increase the discriminating ability of these indices. © 2015 John Wiley & Sons Ltd.

  15. A novel double-focusing time-of-flight mass spectrometer for absolute recoil ion cross sections measurements

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Sigaud, L., E-mail: lsigaud@if.uff.br; Jesus, V. L. B. de; Ferreira, Natalia

    In this work, the inclusion of an Einzel-like lens inside the time-of-flight drift tube of a standard mass spectrometer coupled to a gas cell—to study ionization of atoms and molecules by electron impact—is described. Both this lens and a conical collimator are responsible for further focalization of the ions and charged molecular fragments inside the spectrometer, allowing a much better resolution at the time-of-flight spectra, leading to a separation of a single mass-to-charge unit up to 100 a.m.u. The procedure to obtain the overall absolute efficiency of the spectrometer and micro-channel plate detector is also discussed.

  16. Absolute and convective instabilities in combined Couette-Poiseuille flow past a neo-Hookean solid

    NASA Astrophysics Data System (ADS)

    Patne, Ramkarn; Shankar, V.

    2017-12-01

    Temporal and spatio-temporal stability analyses are carried out to characterize the occurrence of convective and absolute instabilities in combined Couette-Poiseuille flow of a Newtonian fluid past a deformable, neo-Hookean solid layer in the creeping-flow limit. Plane Couette flow of a Newtonian fluid past a neo-Hookean solid becomes temporally unstable in the inertia-less limit when the parameter Γ = V η/(GR) exceeds a critical value. Here, V is the velocity of the top plate, η is the fluid viscosity, G is the shear modulus of the solid layer, and R is the fluid layer thickness. The Kupfer-Bers method is employed to demarcate regions of absolute and convective instabilities in the Γ-H parameter space, where H is the ratio of solid to fluid thickness in the system. For certain ranges of the thickness ratio H, we find that the flow could be absolutely unstable, and the critical Γ required for absolute instability is very close to that for temporal instability, thus making the flow absolutely unstable at the onset of temporal instability. In some cases, there is a gap in the parameter Γ between the temporal and absolute instability boundaries. The present study thus shows that absolute instabilities are possible, even at very low Reynolds numbers in flow past deformable solid surfaces. The presence of absolute instabilities could potentially be exploited in the enhancement of mixing at low Reynolds numbers in flow through channels with deformable solid walls.

  17. A vibration correction method for free-fall absolute gravimeters

    NASA Astrophysics Data System (ADS)

    Qian, J.; Wang, G.; Wu, K.; Wang, L. J.

    2018-02-01

    An accurate determination of gravitational acceleration, usually approximated as 9.8 m s-2, has been playing an important role in the areas of metrology, geophysics, and geodetics. Absolute gravimetry has been experiencing rapid developments in recent years. Most absolute gravimeters today employ a free-fall method to measure gravitational acceleration. Noise from ground vibration has become one of the most serious factors limiting measurement precision. Compared to vibration isolators, the vibration correction method is a simple and feasible way to reduce the influence of ground vibrations. A modified vibration correction method is proposed and demonstrated. A two-dimensional golden section search algorithm is used to search for the best parameters of the hypothetical transfer function. Experiments using a T-1 absolute gravimeter are performed. It is verified that for an identical group of drop data, the modified method proposed in this paper can achieve better correction effects with much less computation than previous methods. Compared to vibration isolators, the correction method applies to more hostile environments and even dynamic platforms, and is expected to be used in a wider range of applications.

  18. An absolute photometric system at 10 and 20 microns

    NASA Technical Reports Server (NTRS)

    Rieke, G. H.; Lebofsky, M. J.; Low, F. J.

    1985-01-01

    Two new direct calibrations at 10 and 20 microns are presented in which terrestrial flux standards are referred to infrared standard stars. These measurements give both good agreement and higher accuracy when compared with previous direct calibrations. As a result, the absolute calibrations at 10 and 20 microns have now been determined with accuracies of 3 and 8 percent, respectively. A variety of absolute calibrations based on extrapolation of stellar spectra from the visible to 10 microns are reviewed. Current atmospheric models of A-type stars underestimate their fluxes by about 10 percent at 10 microns, whereas models of solar-type stars agree well with the direct calibrations. The calibration at 20 microns can probably be determined to about 5 percent by extrapolation from the more accurate result at 10 microns. The photometric system at 10 and 20 microns is updated to reflect the new absolute calibration, to base its zero point directly on the colors of A0 stars, and to improve the accuracy in the comparison of the standard stars.

  19. Wide-field absolute transverse blood flow velocity mapping in vessel centerline

    NASA Astrophysics Data System (ADS)

    Wu, Nanshou; Wang, Lei; Zhu, Bifeng; Guan, Caizhong; Wang, Mingyi; Han, Dingan; Tan, Haishu; Zeng, Yaguang

    2018-02-01

    We propose a wide-field absolute transverse blood flow velocity measurement method in vessel centerline based on absorption intensity fluctuation modulation effect. The difference between the light absorption capacities of red blood cells and background tissue under low-coherence illumination is utilized to realize the instantaneous and average wide-field optical angiography images. The absolute fuzzy connection algorithm is used for vessel centerline extraction from the average wide-field optical angiography. The absolute transverse velocity in the vessel centerline is then measured by a cross-correlation analysis according to instantaneous modulation depth signal. The proposed method promises to contribute to the treatment of diseases, such as those related to anemia or thrombosis.

  20. R-matrix electron-impact excitation data for the Li-like iso-electronic sequence including Auger and radiation damping

    NASA Astrophysics Data System (ADS)

    Liang, G. Y.; Badnell, N. R.

    2011-04-01

    We present results for the electron-impact excitation of all Li-like ions from Be+ to Kr33+ which we obtained using the radiation- and Auger-damped intermediate-coupling frame transformation R-matrix approach. We have included both valence- and core-electron excitations up to the 1s25l and 1s2l4l' levels, respectively. A detailed comparison of the target structure and collision data has been made for four specific ions (O5+, Ar15+, Fe23+ and Kr33+) spanning the sequence so as to assess the accuracy for the entire sequence. Effective collision strengths (Υs) are presented at temperatures ranging from 2 × 102(z + 1)2 K to 2 × 106(z + 1)2 K (where z is the residual charge of the ions, i.e. Z - 3). Detailed comparisons for the Υs are made with the results of previous calculations for several ions which span the sequence. The radiation and Auger damping effects were explored for core-excitations along the iso-electronic sequence. Furthermore, we examined the iso-electronic trends of effective collision strengths as a function of temperature. These data are made available in the archives of APAP via http://www.apap-network.org, OPEN-ADAS via http://open.adas.ac.uk, as well as anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsweb.u-strasbg.fr/cgi-bin/qcat?J/A+A/528/A69

  1. On the assimilation of absolute geodetic dynamic topography in a global ocean model: impact on the deep ocean state

    NASA Astrophysics Data System (ADS)

    Androsov, Alexey; Nerger, Lars; Schnur, Reiner; Schröter, Jens; Albertella, Alberta; Rummel, Reiner; Savcenko, Roman; Bosch, Wolfgang; Skachko, Sergey; Danilov, Sergey

    2018-05-01

    General ocean circulation models are not perfect. Forced with observed atmospheric fluxes they gradually drift away from measured distributions of temperature and salinity. We suggest data assimilation of absolute dynamical ocean topography (DOT) observed from space geodetic missions as an option to reduce these differences. Sea surface information of DOT is transferred into the deep ocean by defining the analysed ocean state as a weighted average of an ensemble of fully consistent model solutions using an error-subspace ensemble Kalman filter technique. Success of the technique is demonstrated by assimilation into a global configuration of the ocean circulation model FESOM over 1 year. The dynamic ocean topography data are obtained from a combination of multi-satellite altimetry and geoid measurements. The assimilation result is assessed using independent temperature and salinity analysis derived from profiling buoys of the AGRO float data set. The largest impact of the assimilation occurs at the first few analysis steps where both the model ocean topography and the steric height (i.e. temperature and salinity) are improved. The continued data assimilation over 1 year further improves the model state gradually. Deep ocean fields quickly adjust in a sustained manner: A model forecast initialized from the model state estimated by the data assimilation after only 1 month shows that improvements induced by the data assimilation remain in the model state for a long time. Even after 11 months, the modelled ocean topography and temperature fields show smaller errors than the model forecast without any data assimilation.

  2. On determining absolute entropy without quantum theory or the third law of thermodynamics

    NASA Astrophysics Data System (ADS)

    Steane, Andrew M.

    2016-04-01

    We employ classical thermodynamics to gain information about absolute entropy, without recourse to statistical methods, quantum mechanics or the third law of thermodynamics. The Gibbs-Duhem equation yields various simple methods to determine the absolute entropy of a fluid. We also study the entropy of an ideal gas and the ionization of a plasma in thermal equilibrium. A single measurement of the degree of ionization can be used to determine an unknown constant in the entropy equation, and thus determine the absolute entropy of a gas. It follows from all these examples that the value of entropy at absolute zero temperature does not need to be assigned by postulate, but can be deduced empirically.

  3. Impact History of the Moon

    NASA Astrophysics Data System (ADS)

    Cohen, B. A.; Bottke, W. F.; Norman, M. V.; van der Bogert, C. H.; Fassett, C. I.; Hiesinger, H.; Joy, K. H.; Mazrouei, S. A.; Nemchin, A.; Neumann, G. A.; Zellner, N. E. B.

    2018-04-01

    Establishing an absolute planetary chronology has important ramifications for understanding the early structure of the solar system and the geologic history of the planets. The Moon is the cornerstone for understanding this impact history.

  4. A novel multi-dimensional absolute distance measurement system using a basic frequency modulated continuous wave radar and an external cavity laser with trilateration metrology

    NASA Astrophysics Data System (ADS)

    Xiong, Xingting; Qu, Xinghua; Zhang, Fumin

    2018-01-01

    We propose and describe a novel multi-dimensional absolute distance measurement system. This system incorporates a basic frequency modulated continuous wave (FMCW) radar and an second external cavity laser (ECL). Through the use of trilateration, the system in our paper can provide 3D resolution inherently range. However, the measured optical path length differences (OPD) is often variable in industrial environments and this will causes Doppler effect, which has greatly impact on the measurement result. With using the second ECL, the system can correct the Doppler effect to ensure the precision of absolute distance measurement. Result of the simulation will prove the influence of Doppler effect.

  5. Electron Impact Exciation of Fe IX

    NASA Astrophysics Data System (ADS)

    Tayal, Swaraj; Zatsarinny, Oleg

    2015-05-01

    Transition probabilities and electron impact excitation collision strengths and rates for astrophysically important extreme ultraviolet lines of Fe IX are calculated. The 322 fine-structure levels of the 3s2 3p6 , 3s2 3p5 3 d , 3 s 3p6 3 d , 3s2 3p5 4 s , and 3s2 3p4 3d2 configurations are included in our calculations. The collision strengths have been calculated using the B-spline Breit-Pauli R-matrix method for all fine-structure transitions among the 322 levels. The mass, Darwin, and spin-orbit relativistic effects are included in the Breit-Pauli Hamiltonian in the scattering calculation. The one-body and two-body relativistic operators are included in the multi-configuration Hartree-Fock calculations of transition probabilities. Several sets of non-orthogonal spectroscopic and correlation radial orbitals are used to obtain accurate description of Fe IX levels and to represent the scattering functions. The calculated excitation energies are in very good agreement with experiment and represents an improvement over the previous calculations. The present collision strengths show reasonable agreement with the previously available R-matrix and distorted-wave calculations. This research is supported by NASA grant from the Solar and Heliophysics Program.

  6. Electron Impact Ionization of Heavier Ions

    NASA Astrophysics Data System (ADS)

    Saha, B. C.

    2006-10-01

    The electron impact ionization (EII) is a dominant ion creation process in various kinds of plasmas. Hydrogenic atoms occurs not only in plasmas but may also be formed due to radiation effects in many organic and inorganic materials. Apart from its fundamental importance in collisional physics the knowledge of the EII cross sections finds its wide applications in modeling astrophysical and fusion plasmas. So the demand of the EIICS is enormous. It is hard to fulfill such a demand either by experimental or ab initio calculations. Thus various analytical and semi-classical models are employed to generate accurate EII cross sections. We report here a modified version [1] of the Bell et. al. equations [2] including both the ionic and relativistic corrections (MBELL). We generalize the MBELL parameters for treating the dependency of the orbital quantum numbers nl; evaluating cross sections for various species at different energies tests the accuracy of the procedure. Detail will be presented at the meeting. [1] A. K. F. Haque, M. A. Uddin, A. K. Basak, K. R. Karim and B. C. Saha, Phys. Rev. A73, 052703 (2006). [2] K. L. Bell, H. B. Gilbody, J. G. Hughes, A. E. Kingston, and F. J. Smith, J. Phys. Chem. Ref. Data 12, 891 (1983).

  7. Fingerprints of flower absolutes using supercritical fluid chromatography hyphenated with high resolution mass spectrometry.

    PubMed

    Santerre, Cyrille; Vallet, Nadine; Touboul, David

    2018-06-02

    Supercritical fluid chromatography hyphenated with high resolution mass spectrometry (SFC-HRMS) was developed for fingerprint analysis of different flower absolutes commonly used in cosmetics field, especially in perfumes. Supercritical fluid chromatography-atmospheric pressure photoionization-high resolution mass spectrometry (SFC-APPI-HRMS) technique was employed to identify the components of the fingerprint. The samples were separated with a porous graphitic carbon (PGC) Hypercarb™ column (100 mm × 2.1 mm, 3 μm) by gradient elution using supercritical CO 2 and ethanol (0.0-20.0 min (2-30% B), 20.0-25.0 min (30% B), 25.0-26.0 min (30-2% B) and 26.0-30.0 min (2% B)) as mobile phase at a flow rate of 1.5 mL/min. In order to compare the SFC fingerprints between five different flower absolutes: Jasminum grandiflorum absolutes, Jasminum sambac absolutes, Narcissus jonquilla absolutes, Narcissus poeticus absolutes, Lavandula angustifolia absolutes from different suppliers and batches, the chemometric procedure including principal component analysis (PCA) was applied to classify the samples according to their genus and their species. Consistent results were obtained to show that samples could be successfully discriminated. Copyright © 2018 Elsevier B.V. All rights reserved.

  8. Telling in-tune from out-of-tune: widespread evidence for implicit absolute intonation.

    PubMed

    Van Hedger, Stephen C; Heald, Shannon L M; Huang, Alex; Rutstein, Brooke; Nusbaum, Howard C

    2017-04-01

    Absolute pitch (AP) is the rare ability to name or produce an isolated musical note without the aid of a reference note. One skill thought to be unique to AP possessors is the ability to provide absolute intonation judgments (e.g., classifying an isolated note as "in-tune" or "out-of-tune"). Recent work has suggested that absolute intonation perception among AP possessors is not crystallized in a critical period of development, but is dynamically maintained by the listening environment, in which the vast majority of Western music is tuned to a specific cultural standard. Given that all listeners of Western music are constantly exposed to this specific cultural tuning standard, our experiments address whether absolute intonation perception extends beyond AP possessors. We demonstrate that non-AP listeners are able to accurately judge the intonation of completely isolated notes. Both musicians and nonmusicians showed evidence for absolute intonation recognition when listening to familiar timbres (piano and violin). When testing unfamiliar timbres (triangle and inverted sine waves), only musicians showed weak evidence of absolute intonation recognition (Experiment 2). Overall, these results highlight a previously unknown similarity between AP and non-AP possessors' long-term musical note representations, including evidence of sensitivity to frequency.

  9. Scholarly Electronic Full-Text Publications via the Internet: Issues and Impacts

    NASA Technical Reports Server (NTRS)

    Kosmin, Linda J.

    1999-01-01

    On-line access to complete texts of scholarly journal articles, conference papers, and books is facilitated by rapidly developing World-wide Web Internet access and capabilities. Meanwhile, print publications continue to be produced and read in spite of the proliferation of many networked electronic publications. The purpose of this presentation is to highlight fundamental issues impacting stakeholder groups, as the trend continues towards migration from paper to affordable ubiquitous networked full-text publications. Librarians, publishers, authors and end-users have various viewpoints, interests, and concerns. There are many issues challenging all stakeholder groups. For instance, all share concerns about administering copyright compliance and enforcing fair use. Uncontrollable electronic downstreaming could result in infringed copyright, while limiting a publisher's entitled revenue stream. Moreover, metered fee-based access may hamper scholarly information research. And, self-authoring on the Internet without peer filtering could lead to information clutter. Many related issues challenge librarians in particular. Among these are rising journal subscription prices, regardless if offered in print or electronic. Some electronic offerings are independent of print, others supplement or duplicate print; several publishers presently require subscribing to print in order to access electronic. Furthermore, numbers of publications are n'ow being marketed via the Internet directly to end-users, which can be viewed as encouraging users to bypass the traditional library. A key issue challenging publishers today is the rapidly expanding electronic user base that is demanding delivery of added-value full-text to desktop computers. Also of growing concern appears to be the decline in print sales to libraries, thereby reducing traditional revenue stream potential. Nowadays, publishers are more hesitant about investing in the production of publications geared toward small niche

  10. Absolute calibration of Kodak Biomax-MS film response to x rays in the 1.5- to 8-keV energy range

    NASA Astrophysics Data System (ADS)

    Marshall, F. J.; Knauer, J. P.; Anderson, D.; Schmitt, B. L.

    2006-10-01

    The absolute response of Kodak Biomax-MS film to x rays in the range from 1.5- to 8-keV has been measured using a laboratory electron-beam generated x-ray source. The measurements were taken at specific line energies by using Bragg diffraction to produce monochromatic beams of x rays. Multiple exposures were taken on Biomax MS film up to levels exceeding optical densities of 2 as measured by a microdensitometer. The absolute beam intensity for each exposure was measured with a Si (Li) detector. Additional response measurements were taken with Kodak direct exposure film (DEF) so as to compare the results of this technique to previously published calibrations. The Biomax-MS results have been fitted to a semiempirical mathematical model (Knauer et al., these proceedings). Users of the model can infer absolute fluences from observed exposure levels at either interpolated or extrapolated energies. To summarize the results: Biomax MS has comparable sensitivity to DEF film below 3keV but has reduced sensitivity above 3keV (˜50%). The lower exposure results from thinner emulsion layers, designed for use with phosphor screens. The ease with which Biomax-MS can be used in place of DEF (same format film, same developing process, and comparable sensitivity) makes it a good replacement.

  11. Improved Absolute Radiometric Calibration of a UHF Airborne Radar

    NASA Technical Reports Server (NTRS)

    Chapin, Elaine; Hawkins, Brian P.; Harcke, Leif; Hensley, Scott; Lou, Yunling; Michel, Thierry R.; Moreira, Laila; Muellerschoen, Ronald J.; Shimada, Joanne G.; Tham, Kean W.; hide

    2015-01-01

    The AirMOSS airborne SAR operates at UHF and produces fully polarimetric imagery. The AirMOSS radar data are used to produce Root Zone Soil Moisture (RZSM) depth profiles. The absolute radiometric accuracy of the imagery, ideally of better than 0.5 dB, is key to retrieving RZSM, especially in wet soils where the backscatter as a function of soil moisture function tends to flatten out. In this paper we assess the absolute radiometric uncertainty in previously delivered data, describe a method to utilize Built In Test (BIT) data to improve the radiometric calibration, and evaluate the improvement from applying the method.

  12. Absolute metrology for space interferometers

    NASA Astrophysics Data System (ADS)

    Salvadé, Yves; Courteville, Alain; Dändliker, René

    2017-11-01

    The crucial issue of space-based interferometers is the laser interferometric metrology systems to monitor with very high accuracy optical path differences. Although classical high-resolution laser interferometers using a single wavelength are well developed, this type of incremental interferometer has a severe drawback: any interruption of the interferometer signal results in the loss of the zero reference, which requires a new calibration, starting at zero optical path difference. We propose in this paper an absolute metrology system based on multiplewavelength interferometry.

  13. Absolute and Convective Instability of a Liquid Jet in Microgravity

    NASA Technical Reports Server (NTRS)

    Lin, Sung P.; Vihinen, I.; Honohan, A.; Hudman, Michael D.

    1996-01-01

    The transition from convective to absolute instability is observed in the 2.2 second drop tower of the NASA Lewis Research Center. In convective instability the disturbance grows spatially as it is convected downstream. In absolute instability the disturbance propagates both downstream and upstream, and manifests itself as an expanding sphere. The transition Reynolds numbers are determined for two different Weber numbers by use of Glycerin and a Silicone oil. Preliminary comparisons with theory are made.

  14. ELECTRON AS A FUNDAMENTAL ELEMENTARY PARTICLE. PART I

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Kakinuma, U.

    1962-12-01

    Elementary particles may be nothing but an electron existing under a certain condition, or a group of electrons that are formed to a certain combined state. Therefore, the knowledge of the electron structure is the starting point of our investigation about matter. To obtain the structure, the electron in an absolutely statical state is considered first and is studied by use of the gage- transformation defined in a modified way. This leads to the discovery oi a revised expression for the electromagnetic energy-tensor inside the electron as well as the wave equation for the electron formally similar to the Schrodingermore » equation for the hydrogen atom. However, our wave equation is interpreted as indicating the mode of energy distribution in the electron. To linearize the wave equation, a complex Riemannian geometry has been developed with results promising to be serviceable for further studies. (auth)« less

  15. System and method for calibrating a rotary absolute position sensor

    NASA Technical Reports Server (NTRS)

    Davis, Donald R. (Inventor); Permenter, Frank Noble (Inventor); Radford, Nicolaus A (Inventor)

    2012-01-01

    A system includes a rotary device, a rotary absolute position (RAP) sensor generating encoded pairs of voltage signals describing positional data of the rotary device, a host machine, and an algorithm. The algorithm calculates calibration parameters usable to determine an absolute position of the rotary device using the encoded pairs, and is adapted for linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters. A method of calibrating the RAP sensor includes measuring the rotary position as encoded pairs of voltage signals, linearly-mapping an ellipse defined by the encoded pairs to thereby calculate the calibration parameters, and calculating an absolute position of the rotary device using the calibration parameters. The calibration parameters include a positive definite matrix (A) and a center point (q) of the ellipse. The voltage signals may include an encoded sine and cosine of a rotary angle of the rotary device.

  16. Photoionization of Ne Atoms and Ne + Ions Near the K Edge: PrecisionSpectroscopy and Absolute Cross-sections

    DOE PAGES

    Müller, Alfred; Bernhardt, Dietrich; Borovik, Alexander; ...

    2017-02-17

    Single, double, and triple photoionization of Ne + ions by single photons have been investigated at the synchrotron radiation source PETRA III in Hamburg, Germany. Absolute cross-sections were measured by employing the photon-ion merged-beams technique. Photon energies were between about 840 and 930 eV, covering the range from the lowest-energy resonances associated with the excitation of one single K-shell electron up to double excitations involving one K- and one L-shell electron, well beyond the K-shell ionization threshold. Also, photoionization of neutral Ne was investigated just below the K edge. The chosen photon energy bandwidths were between 32 and 500 meV,more » facilitating the determination of natural line widths. The uncertainty of the energy scale is estimated to be 0.2 eV. For comparison with existing theoretical calculations, astrophysically relevant photoabsorption cross-sections were inferred by summing the measured partial ionization channels. Discussion of the observed resonances in the different final ionization channels reveals the presence of complex Auger-decay mechanisms. The ejection of three electrons from the lowest K-shell-excited Ne + (1s2s 2p 6 2S 1/2) level, for example, requires cooperative interaction of at least four electrons.« less

  17. Copper fine-structure K-shell electron impact ionization cross sections for fast-electron diagnostic in laser-solid experiments

    DOE Office of Scientific and Technical Information (OSTI.GOV)

    Palmeri, P., E-mail: patrick.palmeri@umons.ac.be; Quinet, P., E-mail: pascal.quinet@umons.ac.be; IPNAS, Université de Liège, B-4000 Liège

    2015-03-15

    The K-shell electron impact ionization (EII) cross section, along with the K-shell fluorescence yield, is one of the key atomic parameters for fast-electron diagnostic in laser-solid experiments through the K-shell emission cross section. In addition, copper is a material that has been often used in those experiments because it has a maximum total K-shell emission yield. Furthermore, in a campaign dedicated to the modeling of the K lines of astrophysical interest (Palmeri et al., 2012), the K-shell fluorescence yields for the K-vacancy fine-structure atomic levels of all the copper isonuclear ions have been calculated. In this study, the K-shell EII crossmore » sections connecting the ground and the metastable levels of the parent copper ions to the daughter ions K-vacancy levels considered in Palmeri et al. (2012) have been determined. The relativistic distorted-wave (DW) approximation implemented in the FAC atomic code has been used for the incident electron kinetic energies up to 10 times the K-shell threshold energies. Moreover, the resulting DW cross sections have been extrapolated at higher energies using the asymptotic form proposed by Davies et al. (2013)« less

  18. A vortex line for K-shell ionization of a carbon atom by electron impact

    NASA Astrophysics Data System (ADS)

    Ward, S. J.; Macek, J. H.

    2014-10-01

    We obtained using the Coulomb-Born approximation a deep minimum in the TDCS for K-shell ionization of a carbon atom by electron impact for the electron ejected in the scattering plane. The minimum is obtained for the kinematics of the energy of incident electron Ei = 1801.2 eV, the scattering angle θf = 4°, the energy of the ejected electron Ek = 5 . 5 eV, and the angle for the ejected electron θk = 239°. This minimum is due to a vortex in the velocity field. At the position of the vortex, the nodal lines of Re [ T ] and Im [ T ] intersect. We decomposed the CB1 T-matrix into its multipole components for the kinematics of a vortex, taking the z'-axis parallel to the direction of the momentum transfer vector. The m = +/- 1 dipole components are necessary to obtain a vortex. We also considered the electron to be ejected out of the scattering plane and obtained the positions of the vortex for different values of the y-component of momentum of the ejected electron, ky. We constructed the vortex line for the kinematics of Ei = 1801.2 eV and θf = 4°. S.J.W. and J.H.M. acknowledge support from NSF under Grant No. PHYS- 0968638 and from D.O.E. under Grant Number DE-FG02-02ER15283, respectively.

  19. Design and performance of an instrument for electron impact tandem mass spectrometry and action spectroscopy of mass/charge selected macromolecular ions stored in RF ion trap*

    NASA Astrophysics Data System (ADS)

    Ranković, Milos Lj.; Giuliani, Alexandre; Milosavljević, Aleksandar R.

    2016-06-01

    A new apparatus was designed, coupling an electron gun with a linear quadrupole ion trap mass spectrometer, to perform m/ z (mass over charge) selected ion activation by electron impact for tandem mass spectrometry and action spectroscopy. We present in detail electron tracing simulations of a 300 eV electron beam inside the ion trap, design of the mechanical parts, electron optics and electronic circuits used in the experiment. We also report examples of electron impact activation tandem mass spectra for Ubiquitin protein, Substance P and Melittin peptides, at incident electron energies in the range from 280 eV to 300 eV.

  20. Linear ultrasonic motor for absolute gravimeter.

    PubMed

    Jian, Yue; Yao, Zhiyuan; Silberschmidt, Vadim V

    2017-05-01

    Thanks to their compactness and suitability for vacuum applications, linear ultrasonic motors are considered as substitutes for classical electromagnetic motors as driving elements in absolute gravimeters. Still, their application is prevented by relatively low power output. To overcome this limitation and provide better stability, a V-type linear ultrasonic motor with a new clamping method is proposed for a gravimeter. In this paper, a mechanical model of stators with flexible clamping components is suggested, according to a design criterion for clamps of linear ultrasonic motors. After that, an effect of tangential and normal rigidity of the clamping components on mechanical output is studied. It is followed by discussion of a new clamping method with sufficient tangential rigidity and a capability to facilitate pre-load. Additionally, a prototype of the motor with the proposed clamping method was fabricated and the performance tests in vertical direction were implemented. Experimental results show that the suggested motor has structural stability and high dynamic performance, such as no-load speed of 1.4m/s and maximal thrust of 43N, meeting the requirements for absolute gravimeters. Copyright © 2017 Elsevier B.V. All rights reserved.