WorldWideScience

Sample records for lyman alpha systems

  1. Lyman Alpha Control

    CERN Document Server

    Nielsen, Daniel Stefaniak

    2015-01-01

    This document gives an overview of how to operate the Lyman Alpha Control application written in LabVIEW along with things to watch out for. Overview of the LabVIEW code itself as well as the physical wiring of and connections from/to the NI PCI-6229 DAQ box is also included. The Lyman Alpha Control application is the interface between the ALPHA sequencer and the HighFinesse Wavelength Meter as well as the Lyman Alpha laser setup. The application measures the wavelength of the output light from the Lyman Alpha cavity through the Wavelength Meter. The application can use the Wavelength Meter’s PID capabilities to stabilize the Lyman Alpha laser output as well as switch between up to three frequencies.

  2. The Lyman alpha reference sample

    DEFF Research Database (Denmark)

    Hayes, M.; Östlin, G.; Schaerer, D.

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028

  3. Variability of the Lyman alpha flux with solar activity

    International Nuclear Information System (INIS)

    Lean, J.L.; Skumanich, A.

    1983-01-01

    A three-component model of the solar chromosphere, developed from ground based observations of the Ca II K chromospheric emission, is used to calculate the variability of the Lyman alpha flux between 1969 and 1980. The Lyman alpha flux at solar minimum is required in the model and is taken as 2.32 x 10 11 photons/cm 2 /s. This value occurred during 1975 as well as in 1976 near the commencement of solar cycle 21. The model predicts that the Lyman alpha flux increases to as much as 5 x 10 11 photons/cm 2 /s at the maximum of the solar cycle. The ratio of the average fluxes for December 1979 (cycle maximum) and July 1976 (cycle minimum) is 1.9. During solar maximum the 27-day solar rotation is shown to cause the Lyman alpha flux to vary by as much as 40% or as little as 5%. The model also shows that the Lyman alpha flux varies over intermediate time periods of 2 to 3 years, as well as over the 11-year sunspot cycle. We conclude that, unlike the sunspot number and the 10.7-cm radio flux, the Lyman alpha flux had a variability that was approximately the same during each of the past three cycles. Lyman alpha fluxes calculated by the model are consistent with measurements of the Lyman alpha flux made by 11 of a total of 14 rocket experiments conducted during the period 1969--1980. The model explains satisfactorily the absolute magnitude, long-term trends, and the cycle variability seen in the Lyman alpha irradiances by the OSO 5 satellite experiment. The 27-day variability observed by the AE-E satellite experiment is well reproduced. However, the magntidue of the AE-E 1 Lyman alpha irradiances are higher than the model calculations by between 40% and 80%. We suggest that the assumed calibration of the AE-E irradiances is in error

  4. Galex Lyman-alpha Emitters: Physical Properties, Luminosity Bimodality, And Morphologies.

    Science.gov (United States)

    Mallery, Ryan P.

    2010-01-01

    The Galaxy Evolution Explorer spectroscopic survey has uncovered a large statistically significant sample of Lyman-alpha emitters at z sim0.3. ACS imaging of these sources in the COSMOS and AEGIS deep fields reveals that these Lyman-alpha emitters consist of two distinct galaxy morphologies, face on spiral galaxies and compact starburst/merging systems. The morphology bimodality also results in a bimodal distribution of optical luminosity. A comparison between the UV photometry and MIPS 24 micron detections of these sources indicates that they are bluer, and have less dust extinction than similar star forming galaxies that lack Lyman-alpha detection. Our findings show how the global gas and dust distribution of star forming galaxies inhibits Lyman-alpha emission in star forming galaxies. GALEX is a NASA Small Explorer, launched in April 2003. We gratefully acknowledge NASA's support for construction, operation, and science analysis for the GALEX mission, developed in cooperation with the CNES of France and the Korean Ministry of Science and Technology.

  5. Development of Flight Slit-Jaw Optics for Chromospheric Lyman-Alpha SpectroPolarimeter

    Science.gov (United States)

    Kubo, Masahito; Suematsu, Yoshinori; Kano, Ryohei; Bando, Takamasa; Hara, Hirohisa; Narukage, Noriyuki; Katsukawa, Yukio; Ishikawa, Ryoko; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; hide

    2015-01-01

    In sounding rocket experiment CLASP, I have placed a slit a mirror-finished around the focal point of the telescope. The light reflected by the mirror surface surrounding the slit is then imaged in Slit-jaw optical system, to obtain the alpha-ray Lyman secondary image. This image, not only to use the real-time image in rocket flight rocket oriented direction selection, and also used as a scientific data showing the spatial structure of the Lyman alpha emission line intensity distribution and solar chromosphere around the observation area of the polarimetric spectroscope. Slit-jaw optical system is a two off-axis mirror unit part including a parabolic mirror and folding mirror, Lyman alpha transmission filter, the optical system magnification 1x consisting camera. The camera is supplied from the United States, and the other was carried out fabrication and testing in all the Japanese side. Slit-jaw optical system, it is difficult to access the structure, it is necessary to install the low place clearance. Therefore, influence the optical performance, the fine adjustment is necessary optical elements are collectively in the form of the mirror unit. On the other hand, due to the alignment of the solar sensor in the US launch site, must be removed once the Lyman alpha transmission filter holder including a filter has a different part from the mirror unit. In order to make the structure simple, stray light measures Aru to concentrate around Lyman alpha transmission filter. To overcome the difficulties of performing optical alignment in Lyman alpha wavelength absorbed by the atmosphere, it was planned following four steps in order to reduce standing time alignment me. 1: is measured in advance refractive index at Lyman alpha wavelength of Lyman alpha transmission filter (121.567nm), to prepare a visible light Firuwo having the same optical path length in the visible light (630nm). 2: The mirror structure CLASP before mounting unit standing, dummy slit and camera standing

  6. THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew [Universite de Toulouse, UPS-OMP, IRAP, Toulouse (France); Oestlin, Goeran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Schaerer, Daniel [CNRS, IRAP, 14, avenue Edouard Belin, F-31400 Toulouse (France); Verhamme, Anne; Orlitova, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Oti-Floranes, Hector [Centro de Astrobiologia (CSIC-INTA), Departamento de Astrofisica, POB 78, 28691 Villanueva de la Canada (Spain); Adamo, Angela [Max Planck Institute for Astronomy, Koenigstuhl 17, D-69117 Heidelberg (Germany); Atek, Hakim [Laboratoire d' Astrophysique, Ecole Polytechnique Federale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Cannon, John M. [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Herenz, E. Christian [Leibniz-Institut fuer Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095 CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter, E-mail: matthew@astro.su.se [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark)

    2013-03-10

    We report on new imaging observations of the Lyman alpha emission line (Ly{alpha}), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 < z < 0.18 in continuum-subtracted Ly{alpha}, H{alpha}, and the far ultraviolet continuum. We show that Ly{alpha} is emitted on scales that systematically exceed those of the massive stellar population and recombination nebulae: as measured by the Petrosian 20% radius, R{sub P20}, Ly{alpha} radii are larger than those of H{alpha} by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Ly{alpha}-to-FUV radii is 2.9. This suggests that much of the Ly{alpha} light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Ly{alpha} compared to H{alpha}, {xi}{sub Ly{alpha}} = R {sup Ly{alpha}}{sub P20}/R {sup H{alpha}}{sub P20}, we find {xi}{sub Ly{alpha}} to be uncorrelated with total Ly{alpha} luminosity. However, {xi}{sub Ly{alpha}} is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Ly{alpha} photons throughout the interstellar medium and drive a large extended Ly{alpha} halo.

  7. Lyman alpha SMM/UVSP absolute calibration and geocoronal correction

    Science.gov (United States)

    Fontenla, Juan M.; Reichmann, Edwin J.

    1987-01-01

    Lyman alpha observations from the Ultraviolet Spectrometer Polarimeter (UVSP) instrument of the Solar Maximum Mission (SMM) spacecraft were analyzed and provide instrumental calibration details. Specific values of the instrument quantum efficiency, Lyman alpha absolute intensity, and correction for geocoronal absorption are presented.

  8. Chromospheric Lyman-alpha spectro-polarimeter (CLASP)

    Science.gov (United States)

    Kano, Ryouhei; Bando, Takamasa; Narukage, Noriyuki; Ishikawa, Ryoko; Tsuneta, Saku; Katsukawa, Yukio; Kubo, Masahito; Ishikawa, Shin-nosuke; Hara, Hirohisa; Shimizu, Toshifumi; Suematsu, Yoshinori; Ichimoto, Kiyoshi; Sakao, Taro; Goto, Motoshi; Kato, Yoshiaki; Imada, Shinsuke; Kobayashi, Ken; Holloway, Todd; Winebarger, Amy; Cirtain, Jonathan; De Pontieu, Bart; Casini, Roberto; Trujillo Bueno, Javier; Štepán, Jiří; Manso Sainz, Rafael; Belluzzi, Luca; Asensio Ramos, Andres; Auchère, Frédéric; Carlsson, Mats

    2012-09-01

    One of the biggest challenges in heliophysics is to decipher the magnetic structure of the solar chromosphere. The importance of measuring the chromospheric magnetic field is due to both the key role the chromosphere plays in energizing and structuring the outer solar atmosphere and the inability of extrapolation of photospheric fields to adequately describe this key boundary region. Over the last few years, significant progress has been made in the spectral line formation of UV lines as well as the MHD modeling of the solar atmosphere. It is found that the Hanle effect in the Lyman-alpha line (121.567 nm) is a most promising diagnostic tool for weaker magnetic fields in the chromosphere and transition region. Based on this groundbreaking research, we propose the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) to NASA as a sounding rocket experiment, for making the first measurement of the linear polarization produced by scattering processes and the Hanle effect in the Lyman-alpha line (121.567 nm), and making the first exploration of the magnetic field in the upper chromosphere and transition region of the Sun. The CLASP instrument consists of a Cassegrain telescope, a rotating 1/2-wave plate, a dual-beam spectrograph assembly with a grating working as a beam splitter, and an identical pair of reflective polarization analyzers each equipped with a CCD camera. We propose to launch CLASP in December 2014.

  9. THE LYMAN ALPHA REFERENCE SAMPLE: EXTENDED LYMAN ALPHA HALOS PRODUCED AT LOW DUST CONTENT

    International Nuclear Information System (INIS)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Guaita, Lucia; Melinder, Jens; Sandberg, Andreas; Schaerer, Daniel; Verhamme, Anne; Orlitová, Ivana; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor; Adamo, Angela; Atek, Hakim; Cannon, John M.; Herenz, E. Christian; Kunth, Daniel; Laursen, Peter

    2013-01-01

    We report on new imaging observations of the Lyman alpha emission line (Lyα), performed with the Hubble Space Telescope, that comprise the backbone of the Lyman alpha Reference Sample. We present images of 14 starburst galaxies at redshifts 0.028 P20 , Lyα radii are larger than those of Hα by factors ranging from 1 to 3.6, with an average of 2.4. The average ratio of Lyα-to-FUV radii is 2.9. This suggests that much of the Lyα light is pushed to large radii by resonance scattering. Defining the Relative Petrosian Extension of Lyα compared to Hα, ξ Lyα = R Lyα P20 /R Hα P20 , we find ξ Lyα to be uncorrelated with total Lyα luminosity. However, ξ Lyα is strongly correlated with quantities that scale with dust content, in the sense that a low dust abundance is a necessary requirement (although not the only one) in order to spread Lyα photons throughout the interstellar medium and drive a large extended Lyα halo.

  10. Recovering the systemic redshift of galaxies from their Lyman-alpha line profile

    Science.gov (United States)

    Verhamme, A.; Garel, T.; Ventou, E.; Contini, T.; Bouché, N.; Herenz, E. C.; Richard, J.; Bacon, R.; Schmidt, K. B.; Maseda, M.; Marino, R. A.; Brinchmann, J.; Cantalupo, S.; Caruana, J.; Clément, B.; Diener, C.; Drake, A. B.; Hashimoto, T.; Inami, H.; Kerutt, J.; Kollatschny, W.; Leclercq, F.; Patrício, V.; Schaye, J.; Wisotzki, L.; Zabl, J.

    2018-04-01

    The Lyman alpha (Lyα) line of Hydrogen is a prominent feature in the spectra of star-forming galaxies, usually redshifted by a few hundreds of km s-1 compared to the systemic redshift. This large offset hampers follow-up surveys, galaxy pair statistics and correlations with quasar absorption lines when only Lyα is available. We propose diagnostics that can be used to recover the systemic redshift directly from the properties of the Lyα line profile. We use spectroscopic observations of Lyman-Alpha Emitters (LAEs) for which a precise measurement of the systemic redshift is available. Our sample contains 13 sources detected between z ≈ 3 and z ≈ 6 as part of various Multi Unit Spectroscopic Explorer (MUSE) Guaranteed Time Observations (GTO). We also include a compilation of spectroscopic Lyα data from the literature spanning a wide redshift range (z ≈ 0 - 8). First, restricting our analysis to double-peaked Lyα spectra, we find a tight correlation between the velocity offset of the red peak with respect to the systemic redshift, V_peak^red, and the separation of the peaks. Secondly, we find a correlation between V_peak^red and the full width at half maximum of the Lyα line. Fitting formulas, to estimate systemic redshifts of galaxies with an accuracy of ≤100 km s-1 when only the Lyα emission line is available, are given for the two methods.

  11. Weighing the Low-Redshift Lyman-alpha Forest

    Science.gov (United States)

    Shull, Mike

    2005-01-01

    In 2003-2004, our FUSE research group prepared several major surveys of the amount of baryonic matter in the intergalactic medium (IGM), using the Far Ultraviolet Spectroscopic Explorer (FUSE) satellite. These surveys include measurements of the Lyman-alpha absorption line of neutral hydrogen (H I), the far-ultraviolet (1032,1038 Angstrom) doublet of highly ionized oxygen ( O VI), the higher Lyman-series lines (Ly-beta, Ly-gamma, etc) of H I, and the 977 Angstrom line of c III. As an overview, our FUSE spectroscopic studies, taken together with data from the Hubble Space Telescope, show that approximately 30% of the normal matter is contained in intergalactic hydrogen gas clouds (the Lyman-alpha forest). Another 5-10% resides in hotter gas at temperatures of 10(exp 5) to 10(exp 6) K, visible in 0 VI and C III absorption. Along with the matter attributed to galaxies, we have now accounted for approximately HALF of all the baryonic matter in the universe. Where is the other half? That matter my exist in even hotter gas, invisible through the ultraviolet absorption lines, but perhaps detectable through X-ray absorption lines of more highly ionized oxygen and neon.

  12. Lyman-alpha detector designed for rocket measurements of the direct solar radiation at 121.5 nm

    International Nuclear Information System (INIS)

    Guineva, V.; Tashev, V.; Witt, G.; Gumbel, J.; Khaplanov, M.

    2007-01-01

    Rocket measurements of the direct Lyman-alpha radiation penetrating in the atmosphere were planned during the HotPay I rocket experiment, June 2006, Project ASLAF (Attenuation of the Solar Lyman-Alpha Flux), Andoya Rocket Range (ARR), Norway. The basic goal of ASLAF project was the study of the processes in the summer mesosphere and thermosphere (up to 110 km), at high latitudes using the Lyman-alpha measurements. The resonance transition 2 P- 2 S of the atomic hydrogen (Lyman-alpha emission) is the strongest and most conspicuous feature in the solar EUV spectrum. Due to the favourable circumstance, that the Lyman-alpha wavelength (121.5 nm) coincides with a minimum of the O 2 absorption spectrum, the direct Lyman-alpha radiation penetrates well in the mesosphere. The Lyman-alpha radiation is the basic agent of the NO molecules ionization, thus generating the ionospheric D-layer, and of the water vapour photolysis, being one of the main H 2 O loss processes. The Lyman-alpha radiation transfer depends on the resonance scattering from the hydrogen atoms in the atmosphere and on the O 2 absorption. Since the Lyman-alpha extinction in the atmosphere is a measure for the column density of the oxygen molecules, the atmospheric temperature profile can be calculated thereof. The detector of solar Lyman-alpha radiation was manufactured in the Stara Zagora Department of the Solar-Terrestrial Influences Laboratory (STIL). Its basic part is an ionization chamber, filled in with NO. A 60 V power supply is applied to the chamber. The produced photoelectric current from the sensor is fed to a 2-channels amplifier, providing an analogue signal. The characteristics of the Lyman-alpha detector were studied. It passed successfully all tests and the results showed that the instrument could be used in rocket experiments to measure the Lyman-alpha flux. From the measurements of the detector, the Lyman-alpha vertical profile can be obtained. The forthcoming scientific data analysis will

  13. A reliable cw Lyman-{alpha} laser source for future cooling of antihydrogen

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Daniel, E-mail: kolbed@uni-mainz.de; Beczkowiak, Anna; Diehl, Thomas; Koglbauer, Andreas; Sattler, Matthias; Stappel, Matthias; Steinborn, Ruth; Walz, Jochen [Johannes Gutenberg-Universitaet, Institut fuer Physik (Germany)

    2012-12-15

    We demonstrate a reliable continuous-wave (cw) laser source at the 1 S-2 P transition in (anti)hydrogen at 121.56 nm (Lyman-{alpha}) based on four-wave sum-frequency mixing in mercury. A two-photon resonance in the four-wave mixing scheme is essential for a powerful cw Lyman-{alpha} source and is well investigated.

  14. Are the brightest Lyman Alpha Emitters at z=5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Jones, Heath; Meisenheimer, Klaus; Pompei, Emanuela; Tapken, Christian; Vanzi, Leonardo; Westra, Eduard

    2008-03-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line, the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at z=6.96, was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as the galaxies discovered through broad band drop out techniques, and, perhaps, more importantly, what role do LAEs play in re-ionising the universe. We recently discovered two extremely luminous LAEs at z=5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. the brightest LAEs are associated to the most massive halos. We propose to use the IRAC 3.6 micron imager on Spitzer to measure the rest-frame optical flux of the these LAEs. With additional data from the near-IR (rest-frame UV) and very deep optical spectra around the Lyman alpha line, we propose to make a detailed study of the spectral energy distribution from the Lyman alpha line to the rest frame optical of these exceptional LAEs. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population, if any, and to estimate the fraction of Lyman continuum photons that can escape the galaxy and are thus available to reionise the universe.

  15. Lyman-alpha clouds as a relic of primordial density fluctuations

    International Nuclear Information System (INIS)

    Bond, J.R.; Szalay, A.S.; Silk, J.

    1988-01-01

    Primordial density fluctuations are studied using a CDM model and primordial clouds some of which are expanding, driven by pressure gradients created when the medium is photionized, and some of which are massive enough to continue collapsing in spite of the pressure. Normalization of CDM models to the clustering properties on large scales are used to predict the parameters of collapsing clouds of subgalactic mass at early epochs. It is shown that the abundance and dimensions of these clouds are comparable to those of the Lyman-alpha systems. The evolutionary history of the clouds is computed, utilizing a spherically symmetric hydrodynamics code with the dark matter treated as a collisionless fluid, and the H I column density distribution is evaluated as a function of N(H I) and redshift. The observed cloud parameters come out naturally in the CDM model and suggest that Lyman-alpha clouds are the missing link between primordial density fluctuations and the formation of galaxies. 31 references

  16. Comparison of Lyman-alpha and LI-COR infrared hygrometers for airborne measurement of turbulent fluctuations of water vapour

    Science.gov (United States)

    Lampert, Astrid; Hartmann, Jörg; Pätzold, Falk; Lobitz, Lennart; Hecker, Peter; Kohnert, Katrin; Larmanou, Eric; Serafimovich, Andrei; Sachs, Torsten

    2018-05-01

    To investigate if the LI-COR humidity sensor can be used as a replacement of the Lyman-alpha sensor for airborne applications, the measurement data of the Lyman-alpha and several LI-COR sensors are analysed in direct intercomparison flights on different airborne platforms. One vibration isolated closed-path and two non-isolated open-path LI-COR sensors were installed on a Dornier 128 twin engine turbo-prop aircraft. The closed-path sensor provided absolute values and fluctuations of the water vapour mixing ratio in good agreement with the Lyman-alpha. The signals of the two open-path sensors showed considerable high-frequency noise, and the absolute value of the mixing ratio was observed to drift with time in this vibrational environment. On the helicopter-towed sensor system Helipod, with very low vibration levels, the open-path LI-COR sensor agreed very well with the Lyman-alpha sensor over the entire frequency range up to 3 Hz. The results show that the LI-COR sensors are well suited for airborne measurements of humidity fluctuations, provided that a vibrationless environment is given, and this turns out to be more important than close sensor spacing.

  17. Lyman alpha emission in nearby star-forming galaxies with the lowest metallicities and the highest [OIII]/[OII] ratios

    Science.gov (United States)

    Izotov, Yuri

    2017-08-01

    The Lyman alpha line of hydrogen is the strongest emission line in galaxies and the tool of predilection for identifying and studying star-forming galaxies over a wide range of redshifts, especially in the early universe. However, it has become clear over the years that not all of the Lyman alpha radiation escapes, due to its resonant scattering on the interstellar and intergalactic medium, and absorption by dust. Although our knowledge of the high-z universe depends crucially on that line, we still do not have a complete understanding of the mechanisms behind the production, radiative transfer and escape of Lyman alpha in galaxies. We wish here to investigate these mechanisms by studying the properties of the ISM in a unique sample of 8 extreme star-forming galaxies (SFGs) that have the highest excitation in the SDSS spectral data base. These dwarf SFGs have considerably lower stellar masses and metallicities, and higher equivalent widths and [OIII]5007/[OII]3727 ratios compared to all nearby SFGs with Lyman alpha emission studied so far with COS. They are, however, very similar to the dwarf Lyman alpha emitters at redshifts 3-6, which are thought to be the main sources of reionization in the early Universe. By combining the HST/COS UV data with data in the optical range, and using photoionization and radiative transfer codes, we will be able to study the properties of the Lyman alpha in these unique objects, derive column densities of the neutral hydrogen N(HI) and compare them with N(HI) obtained from the HeI emission-line ratios in the optical spectra. We will derive Lyman alpha escape fractions and indirectly Lyman continuum escape fractions.

  18. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1 percent in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1 percent polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30 percent) quantum efficiency at the Lyman-alpha line. The CLASP cameras were designed to operate with 10 e-/pixel/second dark current, 25 e- read noise, a gain of 2.0 +/- 0.5 and 1.0 percent residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  19. Performance Characterization of UV Science Cameras Developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Champey, Patrick; Kobayashi, Ken; Winebarger, Amy; Cirtin, Jonathan; Hyde, David; Robertson, Bryan; Beabout, Brent; Beabout, Dyana; Stewart, Mike

    2014-01-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-alpha and to detect the Hanle effect in the line core. Due to the nature of Lyman-alpha polarization in the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. Coating the e2v CCD57-10 512x512 detectors with Lumogen-E coating allows for a relatively high (30%) quantum efficiency at the Lyman-$\\alpha$ line. The CLASP cameras were designed to operate with =10 e- /pixel/second dark current, = 25 e- read noise, a gain of 2.0 and =0.1% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  20. The Lyman Alpha Imaging-Monitor Experiment (LAIME) for TESIS/CORONAS-PHOTON

    Science.gov (United States)

    Damé, L.; Koutchmy, S.; Kuzin, S.; Lamy, P.; Malherbe, J.-M.; Noëns, J.-C.

    LAIME the Lyman Alpha Imaging-Monitor Experiment is a remarkably simple no mechanisms and compact 100x100x400 mm full Sun imager to be flown with TESIS on the CORONAS-PHOTON mission launch expected before mid-2008 As such it will be the only true chromospheric imager to be flown in the next years supporting TESIS EUV-XUV imaging SDO and the Belgian LYRA Lyman Alpha flux monitor on the ESA PROBA-2 microsatellite launch expected in September 2007 We will give a short description of this unique O60 mm aperture imaging telescope dedicated to the investigating of the magnetic sources of solar variability in the UV and chromospheric and coronal disruptive events rapid waves Moreton waves disparitions brusques of prominences filaments eruptions and CMEs onset The resolution pixel is 2 7 arcsec the field of view 1 4 solar radius and the acquisition cadence could be as high as 1 image minute The back thinned E2V CCD in the focal plane is using frame transfer to avoid shutter and mechanisms Further more the double Lyman Alpha filtering allows a 40 AA FWHM bandwidth and excellent rejection yet providing a vacuum seal design of the telescope MgF2 entrance window Structural stability of the telescope focal length 1 m is preserved by a 4-INVAR bars design with Aluminium compensation in a large pm 10 o around 20 o

  1. Correlations in the three-dimensional Lyman-alpha forest contaminated by high column density absorbers

    Science.gov (United States)

    Rogers, Keir K.; Bird, Simeon; Peiris, Hiranya V.; Pontzen, Andrew; Font-Ribera, Andreu; Leistedt, Boris

    2018-05-01

    Correlations measured in three dimensions in the Lyman-alpha forest are contaminated by the presence of the damping wings of high column density (HCD) absorbing systems of neutral hydrogen (H I; having column densities N(H I) > 1.6 × 10^{17} atoms cm^{-2}), which extend significantly beyond the redshift-space location of the absorber. We measure this effect as a function of the column density of the HCD absorbers and redshift by measuring three-dimensional (3D) flux power spectra in cosmological hydrodynamical simulations from the Illustris project. Survey pipelines exclude regions containing the largest damping wings. We find that, even after this procedure, there is a scale-dependent correction to the 3D Lyman-alpha forest flux power spectrum from residual contamination. We model this residual using a simple physical model of the HCD absorbers as linearly biased tracers of the matter density distribution, convolved with their Voigt profiles and integrated over the column density distribution function. We recommend the use of this model over existing models used in data analysis, which approximate the damping wings as top-hats and so miss shape information in the extended wings. The simple `linear Voigt model' is statistically consistent with our simulation results for a mock residual contamination up to small scales (|k| account for the effect of the highest column density absorbers on the smallest scales (e.g. |k| > 0.4 h Mpc^{-1} for small damped Lyman-alpha absorbers; HCD absorbers with N(H I) ˜ 10^{21} atoms cm^{-2}). However, these systems are in any case preferentially removed from survey data. Our model is appropriate for an accurate analysis of the baryon acoustic oscillations feature. It is additionally essential for reconstructing the full shape of the 3D flux power spectrum.

  2. Are the brightest Lyman Alpha Emitters at zD5.7 primeval galaxies?

    Science.gov (United States)

    Lidman, Christopher; Hayes, Matthew; Jones, Heath; Meisenheimer, Klaus; Tapken, Christian; Westra, Eduard

    2009-04-01

    Wide-field, narrow-band surveys have proven to be effective at finding very high redshift galaxies that emit brightly in the Lyman alpha line - the so-called Lyman alpha emitters (LAEs). It was through this technique that the most distant spectroscopically confirmed galaxy, a galaxy at zD6.96 (Iye et al. 2006), was discovered. Considerable effort is currently being spent on discovering these galaxies at ever higher redshifts by extending this technique into the near-IR. In contrast to this effort, there has been relatively little work on understanding these galaxies. In particular, how do LAEs relate to other high redshift galaxies, such as those discovered through drop out techniques, and, more importantly, what role LAEs play in re-ionising the universe, if any. We recently discovered two extremely luminous LAEs at zD5.7. These LAEs are among the brightest LAEs ever discovered at this redshift. In a recent paper by Mao et al. (2007), the brightest LAEs are associated to the most massive halos. One of these targets was successfully observed with the IRAC 3.6 micron imager on Spitzer during cycle 5. These data, when combined with constraints that we derive from our deep ground-based spectroscopic data, indicate that the bulk of the flux at 3.6 microns comes from a stellar population that is considserably older than the stars that dominate the flux in the UV. We propose to complete the project and image the second target. These data will enable us to estimate the age and mass of the stellar burst that produces the Lyman alpha line, to estimate the contribution from an older stellar population and to estimate the fraction of Lyman continuum photons that escape the galaxy and are thus available to re-ionise the universe.

  3. A Sounding Rocket Experiment for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Kubo, M.; Kano, R.; Kobayashi, K.; Bando, T.; Narukage, N.; Ishikawa, R.; Tsuneta, S.; Katsukawa, Y.; Ishikawa, S.; Suematsu, Y.; Hara, H.; Shimizu, T.; Sakao, T.; Ichimoto, K.; Goto, M.; Holloway, T.; Winebarger, A.; Cirtain, J.; De Pontieu, B.; Casini, R.; Auchère, F.; Trujillo Bueno, J.; Manso Sainz, R.; Belluzzi, L.; Asensio Ramos, A.; Štěpán, J.; Carlsson, M.

    2014-10-01

    A sounding-rocket experiment called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is presently under development to measure the linear polarization profiles in the hydrogen Lyman-alpha (Lyα) line at 121.567 nm. CLASP is a vacuum-UV (VUV) spectropolarimeter to aim for first detection of the linear polarizations caused by scattering processes and the Hanle effect in the Lyα line with high accuracy (0.1%). This is a fist step for exploration of magnetic fields in the upper chromosphere and transition region of the Sun. Accurate measurements of the linear polarization signals caused by scattering processes and the Hanle effect in strong UV lines like Lyα are essential to explore with future solar telescopes the strength and structures of the magnetic field in the upper chromosphere and transition region of the Sun. The CLASP proposal has been accepted by NASA in 2012, and the flight is planned in 2015.

  4. [O III] EMISSION AND GAS KINEMATICS IN A LYMAN-ALPHA BLOB AT z {approx} 3.1

    Energy Technology Data Exchange (ETDEWEB)

    McLinden, Emily M. [McDonald Observatory, University of Texas at Austin, Austin, TX 78712 (United States); Malhotra, Sangeeta; Rhoads, James E. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Hibon, Pascale [Gemini Observatory, La Serena (Chile); Weijmans, Anne-Marie [Dunlap Institute for Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada); Tilvi, Vithal [George P. and Cynthia Woods Mitchell Institute for Fundamental Physics and Astronomy, and Department of Physics and Astronomy, Texas A and M University, College Station, TX 77843 (United States)

    2013-04-10

    We present spectroscopic measurements of the [O III] emission line from two subregions of strong Ly{alpha} emission in a radio-quiet Lyman-alpha blob (LAB). The blob under study is LAB1 at z {approx} 3.1, and the [O III] detections are from the two Lyman break galaxies (LBGs) embedded in the blob halo. The [O III] measurements were made with LUCIFER on the 8.4 m Large Binocular Telescope and NIRSPEC on 10 m Keck Telescope. Comparing the redshift of the [O III] measurements to Ly{alpha} redshifts from SAURON allows us to take a step toward understanding the kinematics of the gas in the blob. Using both LUCIFER and NIRSPEC we find velocity offsets between the [O III] and Ly{alpha} redshifts that are modestly negative or consistent with 0 km s{sup -1} in both subregions studied (ranging from -72 {+-} 42- + 6 {+-} 33 km s{sup -1}). A negative offset means Ly{alpha} is blueshifted with respect to [O III] a positive offset then implies Ly{alpha} is redshifted with respect to [O III]. These results may imply that outflows are not primarily responsible for Lyman alpha escape in this LAB, since outflows are generally expected to produce a positive velocity offset. In addition, we present an [O III] line flux upper limit on a third region of LAB1, a region that is unassociated with any underlying galaxy. We find that the [O III] upper limit from the galaxy-unassociated region of the blob is at least 1.4-2.5 times fainter than the [O III] flux from one of the LBG-associated regions and has an [O III] to Ly{alpha} ratio measured at least 1.9-3.4 times smaller than the same ratio measured from one of the LBGs.

  5. Solar Lyman-Alpha Polarization Observation of the Chromosphere and Transition Region by the Sounding Rocket Experiment CLASP

    Science.gov (United States)

    Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shinnosuke; Hara, Hiroshi; Suematsu, Yoshinori; Giono, Gabriel; hide

    2015-01-01

    We are planning an international rocket experiment Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is (2015 planned) that Lyman a line (Ly(alpha) line) polarization spectroscopic observations from the sun. The purpose of this experiment, detected with high accuracy of the linear polarization of the Ly(alpha) lines to 0.1% by using a Hanle effect is to measure the magnetic field of the chromosphere-transition layer directly. For polarization photometric accuracy achieved that approx. 0.1% required for CLASP, it is necessary to realize the monitoring device with a high throughput. On the other hand, Ly(alpha) line (vacuum ultraviolet rays) have a sensitive characteristics that is absorbed by the material. We therefore set the optical system of the reflection system (transmission only the wavelength plate), each of the mirrors, subjected to high efficiency of the multilayer coating in accordance with the role. Primary mirror diameter of CLASP is about 30 cm, the amount of heat about 30,000 J is about 5 minutes of observation time is coming mainly in the visible light to the telescope. In addition, total flux of the sun visible light overwhelmingly large and about 200 000 times the Ly(alpha) line wavelength region. Therefore, in terms of thermal management and 0.1% of the photometric measurement accuracy achieved telescope, elimination of the visible light is essential. We therefore, has a high reflectivity (> 50%) in Lya line, visible light is a multilayer coating be kept to a low reflectance (Science was achieved a high throughput as a device for a vacuum ultraviolet ray of the entire system less than 5% (CCD of QE is not included).

  6. Diagnosing the reionization of the universe - The absorption spectrum of the intergalactic medium and Lyman alpha clouds

    Science.gov (United States)

    Giroux, Mark L.; Shapiro, Paul R.

    1991-01-01

    The thermal and ionization evolution of a uniform intergalactic medium composed of H and He and undergoing reionization is studied. The diagnosis of the metagalactic ionizing radiation background at z of about three using metal line ratios for Lyman limit quasar absorption line systems is addressed. The use of the He II Gunn-Peterson effect to diagnose the reionization source and/or nature of the Hy-alpha forest clouds is considered.

  7. Performance Characterization of the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) CCD Cameras

    Science.gov (United States)

    Joiner, R. K.; Kobayashi, K.; Winebarger, A. R.; Champey, P. R.

    2014-12-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding rocket instrument which is currently being developed by NASA's Marshall Space Flight Center (MSFC) and the National Astronomical Observatory of Japan (NAOJ). The goal of this instrument is to observe and detect the Hanle effect in the scattered Lyman-Alpha UV (121.6nm) light emitted by the Sun's Chromosphere to make measurements of the magnetic field in this region. In order to make accurate measurements of this effect, the performance characteristics of the three on-board charge-coupled devices (CCDs) must meet certain requirements. These characteristics include: quantum efficiency, gain, dark current, noise, and linearity. Each of these must meet predetermined requirements in order to achieve satisfactory performance for the mission. The cameras must be able to operate with a gain of no greater than 2 e-/DN, a noise level less than 25e-, a dark current level which is less than 10e-/pixel/s, and a residual non-linearity of less than 1%. Determining these characteristics involves performing a series of tests with each of the cameras in a high vacuum environment. Here we present the methods and results of each of these performance tests for the CLASP flight cameras.

  8. New evidence from the Lyman-alpha forest concerning the formation of galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Wolfe, A M

    1986-12-17

    A new type of survey for galaxies with z > 2 is described. The idea is to search for the spectroscopic imprint that the H1 disc of a foreground galaxy leaves on radiation emitted by a background QSO; namely, a Lyman-..cap alpha.. absorption line broadened by radiation damping. A continuing survey has revealed the presence of 15 damped L..cap alpha.. lines with redshifts between 1.8 and 2.8 in the spectra of 68 QSOs. In comparison, no more than three discs with the properties of nearby galaxies should have been detected. Furthermore, the mean column density of the 15 absorbers, = 1.4 x 10/sup 21/cm/sup -2/, is much larger than expected for the outskirts of H1 discs. The statistical and physical evidence accumulated suggests that the damped L..cap alpha.. systems are a distinct population of absorbers with properties reminiscent of H1 discs. It is concluded that the progenitors of the baryon content of nearby galaxies have been detected. The implications for theories of galaxy formations of the discovery of this damped population of absorbers are explained.

  9. Clasp/SJ Observation of Time Variations of Lyman-Alpha Emissions in a Solar Active Region

    Science.gov (United States)

    Ishikawa, S.; Kubo, M.; Katsukawa, Y.; Kano, R.; Narukage, N.; Ishikawa, R.; Bando, T.; Winebarger, A.; Kobayashi, K.; Trujillo Bueno, J.; hide

    2016-01-01

    The Chromospheric Lyman-alpha SpectroPolarimeter (CLASP) is a sounding rocket experiment launched on September 3, 2015 to investigate the solar chromosphere, and the slit-jaw (SJ) optical system took Lya images with the high time cadence of 0.6 s. By the CLASP/SJ observation, many time variations in the solar chromosphere with the time scale of region and investigated the short (regions. As the result, we found the regions. On the other hand, the <30 s time variations had no dependency on the temperature of the loop.

  10. Detection of 3-Minute Oscillations in Full-Disk Lyman-alpha Emission During A Solar Flare

    Science.gov (United States)

    Milligan, R. O.; Ireland, J.; Fleck, B.; Hudson, H. S.; Fletcher, L.; Dennis, B. R.

    2017-12-01

    We report the detection of chromospheric 3-minute oscillations in disk-integrated EUV irradiance observations during a solar flare. A wavelet analysis of detrended Lyman-alpha (from GOES/EUVS) and Lyman continuum (from SDO/EVE) emission from the 2011 February 15 X-class flare revealed a 3-minute period present during the flare's main phase. The formation temperature of this emission locates this radiation to the flare's chromospheric footpoints, and similar behaviour is found in the SDO/AIA 1600A and 1700A channels, which are dominated by chromospheric continuum. The implication is that the chromosphere responds dynamically at its acoustic cutoff frequency to an impulsive injection of energy. Since the 3-minute period was not found at hard X-ray energies (50-100 keV) in RHESSI data we can state that this 3-minute oscillation does not depend on the rate of energization of, or energy deposition by, non-thermal electrons. However, a second period of 120 s found in both hard X-ray and chromospheric emission is consistent with episodic electron energization on 2-minute timescales. Our finding on the 3-minute oscillation suggests that chromospheric mechanical energy should be included in the flare energy budget, and the fluctuations in the Lyman-alpha line may influence the composition and dynamics of planetary atmospheres during periods of high activity.

  11. Analysis of coronal H I Lyman alpha measurements from a rocket flight on 1979 April 13

    Science.gov (United States)

    Withbroe, G. L.; Kohl, J. L.; Weiser, H.; Noci, G.; Munro, R. H.

    1982-01-01

    It is noted that measurements of the profiles of resonantly scattered hydrogen Lyman-alpha coronal radiation have been used in determining hydrogen kinetic temperatures from 1.5 to 4 solar radii from sun center in a quiet region of the corona. Proton temperatures derived using the line widths decrease with height from 2.6 x 10 to the 6th K at 1.5 solar radii to 1.2 x 10 to the 6th K at 4 solar radii. These measurements, together with temperatures for lower heights determined from earlier Skylab and eclipse data, suggest that there is a maximum in the quiet coronal proton temperature at about 1.5 solar radii. Comparison of measured Lyman-alpha intensities with those calculated using a representative model for the radial variation of the coronal electron density yields information on the magnitude of the electron temperature gradient and suggests that the solar wind flow was subsonic for distances less than 4 solar radii.

  12. Lenses in the forest: cross correlation of the Lyman-alpha flux with cosmic microwave background lensing.

    Science.gov (United States)

    Vallinotto, Alberto; Das, Sudeep; Spergel, David N; Viel, Matteo

    2009-08-28

    We present a theoretical estimate for a new observable: the cross correlation between the Lyman-alpha flux fluctuations in quasar spectra and the convergence of the cosmic microwave background as measured along the same line of sight. As a first step toward the assessment of its detectability, we estimate the signal-to-noise ratio using linear theory. Although the signal-to-noise is small for a single line of sight and peaks at somewhat smaller redshifts than those probed by the Lyman-alpha forest, we estimate a total signal-to-noise of 9 for cross correlating quasar spectra of SDSS-III with Planck and 20 for cross correlating with a future polarization based cosmic microwave background experiment. The detection of this effect would be a direct measure of the neutral hydrogen-matter cross correlation and could provide important information on the growth of structures at large scales in a redshift range which is still poorly probed.

  13. The Faint End of the Lyman Alpha Luminosity Function at 2 < z < 3.8

    Science.gov (United States)

    Devarakonda, Yaswant; Livermore, Rachael; Indahl, Briana; Wold, Isak; Davis, Dustin; Finkelstein, Steven

    2018-01-01

    Most current models predict that our universe is mostly composed of small, dim galaxies. Due to these galaxies being so faint, it is very difficult to study these types of galaxies outside of our local universe. This is particularly an issue for studying how these small galaxies evolved over their lifetimes. With the benefit of gravitational lensing, however, we are able to observe galaxies that are farther and fainter than ever before possible. In this particular study, we focus on Lyman-Alpha emitting galaxies between the redshifts of 2-3.8, so that we may study these galaxies during the epoch of peak star formation in the universe. We use the McDonald Observatory 2.7, Harlan Smith telescope with the VIRUS-P IFU spectrograph to observe several Hubble Frontier Field lensing clusters to spectroscopically discover faint galaxies over this redshift range. In addition to providing insight into the faint-end slope of the Lyman alpha luminosity function, the spectroscopic redshifts will allow us to better constrain the mass models of the foreground clusters, such as Abell 370, so that we may better understand lensing effects for this and future studies.

  14. Interpreting HST observations with simulations of reionization: the ionizing photon budget and the decline of Lyman-alpha emission in z>6 dropouts

    Science.gov (United States)

    D'Aloisio, Anson

    2017-08-01

    In recent years, HST surveys such as CANDELS, HUDF, BoRG/HIPPIES, ERS, and the Frontier Fields, have made possible the first robust measurements of the rest-frame UV luminosity function of z =6-10 galaxies, spanning much of the redshift range over which reionization likely occurred. These measurements provide an estimate of the galactic ionizing photon output, addressing the critical question of whether these galaxies could have reionized the Universe. In addition, follow-up spectroscopy has measured the fraction of these galaxies that show Lyman-alpha emission. Interestingly, a dramatic decrease in this fraction above z 6 has been observed, and this evolution has (controversially) been interpreted as evidence that much of reionization happened over z=6-8 (as intergalactic neutral gas leads to large damping wings that scatter the Lyman-alpha line). The clumpiness of the IGM and how it self shields to ionizing photons impacts whether the observed population of galaxies can reionize the Universe, as well as the interpretation of the evolving Lyman-alpha emitter fraction. We propose to run fully coupled radiative-hydrodynamics simulations that are the first to resolve the evaporation of small structures by passing ionization fronts and, hence, to accurately assess the level of clumpiness and self-shielding from the IGM. Our study will nail down the clumping factor used to assess whether the observed population of galaxies can drive reionization, and it will address whether neutral self-shielding clumps in recently reionized regions can scatter galaxies' Lyman-alpha lines.

  15. Continuous coherent Lyman-alpha excitation of atomic hydrogen.

    NARCIS (Netherlands)

    Eikema, K.S.E.; Waltz, J.; Hänsch, T.

    2001-01-01

    The first near natural linewidth of the 1S-2P transition in atomic hydrogen was reported with a high degree of accuracy. A high yield of continuous Lyman-α radiation based on four wave mixing in mercury was employed. It was shown that laser cooloing and detection with Lyman-α radiation has excellent

  16. Ultraviolet photometry from the orbiting astronomical observatory. XVI - The stellar Lyman-alpha absorption line

    Science.gov (United States)

    Savage, B. D.; Panek, R. J.

    1974-01-01

    The stellar Lyman-alpha line at 1216 A was observed in 29 lightly reddened stars of spectral type B2.5 to B9 by a far-UV spectrophotometer on OAO-2. The equivalent widths obtained range from 15 A at type B2.5 to 65 A at type B8; in the late-B stars, the L-alpha line removes 2 to 3% of the total stellar flux. In this sampling, the strength of the L-alpha line correlates well with measures of the Balmer discontinuity and Balmer line strengths; luminosity classification does not seem to affect the line strength. The observed line widths also agree with the predictions of Mihala's grid of non-LTE model atmospheres. In some cases, the L-alpha line influences the interstellar column densities reported in the interstellar OAO-2 L-alpha survey. Hence, these data toward lightly reddened B2 and B1.5 stars should be regarded as upper limits only.

  17. Study of interplanetary hydrogen from Lyman alpha emission and absorption determination

    International Nuclear Information System (INIS)

    Cazes, Serge.

    1979-09-01

    The purpose of the work submitted in this paper is to contribute to the study of interplanetary hydrogen from Lyman alpha emission and absorption measurements, carried out on board the D2A, OSO-8 and Copernicus satellites. This study, which was undertaken from the D2A satellite, moved us to study the interplanetary environment as from observations made from the following experiments placed on board the OSO-8 and Copernicus satellites. The experiment set up on board the OSO-8 satellite made it possible to obtain the profile of the solar alpha Lyman emission. An absorption profile was observed for the first time on these profiles and this made it possible to attribute them to interplanetary hydrogen and enabled us to make a direct and local determination of the solar ionization rate. - The spectrometer set up on board Copernicus made it possible to obtain the emission spectrum of the interplanetary environment at the same time as the geocorona. The overall velocity of the interplanetary environment was deduced from the Doppler shift between the two spectra. In the first part, the principle of the REA and POLAR experiments is recalled but only the REA experiment is described in detail, particularly the problems arising from the construction and calibration of the cell. In the second part, a study of the interplanetary environment made from the D2A determinations is presented in synthesized form. On the other hand, the study to which theses initial results led us is presented in detail. Finally, in the third part, the results obtained by means of the OSO-8 and Copernicus satellites are given [fr

  18. Performance characterization of UV science cameras developed for the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP)

    Science.gov (United States)

    Champey, P.; Kobayashi, K.; Winebarger, A.; Cirtain, J.; Hyde, D.; Robertson, B.; Beabout, D.; Beabout, B.; Stewart, M.

    2014-07-01

    The NASA Marshall Space Flight Center (MSFC) has developed a science camera suitable for sub-orbital missions for observations in the UV, EUV and soft X-ray. Six cameras will be built and tested for flight with the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP), a joint National Astronomical Observatory of Japan (NAOJ) and MSFC sounding rocket mission. The goal of the CLASP mission is to observe the scattering polarization in Lyman-α and to detect the Hanle effect in the line core. Due to the nature of Lyman-α polarizationin the chromosphere, strict measurement sensitivity requirements are imposed on the CLASP polarimeter and spectrograph systems; science requirements for polarization measurements of Q/I and U/I are 0.1% in the line core. CLASP is a dual-beam spectro-polarimeter, which uses a continuously rotating waveplate as a polarization modulator, while the waveplate motor driver outputs trigger pulses to synchronize the exposures. The CCDs are operated in frame-transfer mode; the trigger pulse initiates the frame transfer, effectively ending the ongoing exposure and starting the next. The strict requirement of 0.1% polarization accuracy is met by using frame-transfer cameras to maximize the duty cycle in order to minimize photon noise. The CLASP cameras were designed to operate with ≤ 10 e-/pixel/second dark current, ≤ 25 e- read noise, a gain of 2.0 +- 0.5 and ≤ 1.0% residual non-linearity. We present the results of the performance characterization study performed on the CLASP prototype camera; dark current, read noise, camera gain and residual non-linearity.

  19. Generation of continuous coherent radiation at Lyman-alpha and 1S-2P Spectroscopy of atomic hydrogen

    NARCIS (Netherlands)

    Pahl, A.; Fendel, P.; Henrich, B.R.; Walz, J.; Hansch, T.W.; Eikema, K.S.E.

    2005-01-01

    Continuous coherent radiation from wavelengths from 121 to 123 nm in the vacuum ultraviolet (VUV) was generated by four-wave sum-frequency mixing in mercury vapor. A yield of 20 nW at Lyman-alpha (121.57 nm) was achieved. We describe the experimental setup in detail and present a calculation of the

  20. Solar minimum Lyman alpha sky background observations from Pioneer Venus orbiter ultraviolet spectrometer - Solar wind latitude variation

    Science.gov (United States)

    Ajello, J. M.

    1990-01-01

    Measurements of interplanetary H I Lyman alpha over a large portion of the celestial sphere were made at the recent solar minimum by the Pioneer Venus orbiter ultraviolet spectrometer. These measurements were performed during a series of spacecraft maneuvers conducted to observe Halley's comet in early 1986. Analysis of these data using a model of the passage of interstellar wind hydrogen through the solar system shows that the rate of charge exchange with solar wind protons is 30 percent less over the solar poles than in the ecliptic. This result is in agreement with a similar experiment performed with Mariner 10 at the previous solar minimum.

  1. Lyman continuum observations of solar flares

    Science.gov (United States)

    Machado, M. E.; Noyes, R. W.

    1978-01-01

    A study is made of Lyman continuum observations of solar flares, using data obtained by the EUV spectroheliometer on the Apollo Telescope Mount. It is found that there are two main types of flare regions: an overall 'mean' flare coincident with the H-alpha flare region, and transient Lyman continuum kernels which can be identified with the H-alpha and X-ray kernels observed by other authors. It is found that the ground level hydrogen population in flares is closer to LTE than in the quiet sun and active regions, and that the level of Lyman continuum formation is lowered in the atmosphere from a mass column density .000005 g/sq cm in the quiet sun to .0003 g/sq cm in the mean flare, and to .001 g/sq cm in kernels. From these results the amount of chromospheric material 'evaporated' into the high temperature region is derived, which is found to be approximately 10 to the 15th g, in agreement with observations of X-ray emission measures.

  2. The Lyman-alpha signature of the first galaxies

    Science.gov (United States)

    Smith, Aaron

    2018-01-01

    Radiation from the first stars and galaxies initiated the dramatic phase transition marking an end to the cosmic dark ages. The emission and absorption signatures from the Lyman-alpha (Lyα) transition of neutral hydrogen have been indispensable in extending the observational frontier for high-redshift galaxies into the epoch of reionization. Lyα radiative transfer provides clues about the processes leading to Lyα escape from individual galaxies and the subsequent transmission through the intergalactic medium. Cosmological simulations incorporating Lyα radiative transfer enhance our understanding of fundamental physics by supplying the inferred spectra and feedback on the gas. In this talk, I will discuss the dynamical impact of Lyα radiation pressure on galaxy formation throughout cosmic reionization with the first fully coupled Lyα radiation-hydrodynamics simulations. Based on a suite of spherically symmetric models and high-resolution ab initio cosmological simulations we find that Lyα radiation pressure is dynamically important during the assembly of direct collapse black holes (DCBHs), which may be the seeds of the first supermassive black holes in the universe. Finally, I will discuss recent advances in Lyα modeling based on current state-of-the-art simulations and observational insights.

  3. Optical Alignment of the Chromospheric Lyman-Alpha SpectroPolarimeter using Sophisticated Methods to Minimize Activities under Vacuum

    Science.gov (United States)

    Giono, G.; Katsukawa, Y.; Ishikawa, R.; Narukage, N.; Kano, R.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; hide

    2016-01-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a sounding-rocket instrument developed at the National Astronomical Observatory of Japan (NAOJ) as a part of an international collaboration. The in- strument main scientific goal is to achieve polarization measurement of the Lyman-alpha line at 121.56 nm emitted from the solar upper-chromosphere and transition region with an unprecedented 0.1% accuracy. For this purpose, the optics are composed of a Cassegrain telescope coated with a "cold mirror" coating optimized for UV reflection and a dual-channel spectrograph allowing for simultaneous observation of the two orthogonal states of polarization. Although the polarization sensitivity is the most important aspect of the instrument, the spatial and spectral resolutions of the instrument are also crucial to observe the chromospheric features and resolve the Ly- pro les. A precise alignment of the optics is required to ensure the resolutions, but experiments under vacuum conditions are needed since Ly-alpha is absorbed by air, making the alignment experiments difficult. To bypass this issue, we developed methods to align the telescope and the spectrograph separately in visible light. We will explain these methods and present the results for the optical alignment of the CLASP telescope and spectrograph. We will then discuss the combined performances of both parts to derive the expected resolutions of the instrument, and compare them with the flight observations performed on September 3rd 2015.

  4. The large-scale cross-correlation of Damped Lyman alpha systems with the Lyman alpha forest: first measurements from BOSS

    Energy Technology Data Exchange (ETDEWEB)

    Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Miralda-Escudé, Jordi [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain); Arnau, Eduard [Institut de Ciències del Cosmos (IEEC/UB), Barcelona, Catalonia (Spain); Carithers, Bill; Ross, Nicholas P.; White, Martin [Lawrence Berkeley National Laboratory, University of California Berkeley, Berkeley, California 94720 (United States); Lee, Khee-Gan [Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117, Heidelberg (Germany); Noterdaeme, Pasquier; Pâris, Isabelle; Petitjean, Patrick; Rollinde, Emmanuel [Institut d' Astrophysique de Paris, Université Paris 6 et CNRS, 98bis blvd. Arago, 75014 Paris (France); Rich, James [CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Schneider, Donald P. [Department of Astronomy and Astrophysics, The Pennsylvania State University, University Park, PA 16802 (United States); York, Donald G., E-mail: font@physik.uzh.ch, E-mail: miralda@icc.ub.edu [Department of Astronomy and Astrophysics and The Fermi Institute, Chicago University, 5640 So. Ellis Ave., Chicago, IL 60637 (United States)

    2012-11-01

    We present the first measurement of the large-scale cross-correlation of Lyα forest absorption and Damped Lyman α systems (DLA), using the 9th Data Release of the Baryon Oscillation Spectroscopic Survey (BOSS). The cross-correlation is clearly detected on scales up to 40h{sup −1}Mpc and is well fitted by the linear theory prediction of the standard Cold Dark Matter model of structure formation with the expected redshift distortions, confirming its origin in the gravitational evolution of structure. The amplitude of the DLA-Lyα cross-correlation depends on only one free parameter, the bias factor of the DLA systems, once the Lyα forest bias factors are known from independent Lyα forest correlation measurements. We measure the DLA bias factor to be b{sub D} = (2.17±0.20)β{sub F}{sup 0.22}, where the Lyα forest redshift distortion parameter β{sub F} is expected to be above unity. This bias factor implies a typical host halo mass for DLAs that is much larger than expected in present DLA models, and is reproduced if the DLA cross section scales with halo mass as M{sub h}{sup α}, with α = 1.1±0.1 for β{sub F} = 1. Matching the observed DLA bias factor and rate of incidence requires that atomic gas remains extended in massive halos over larger areas than predicted in present simulations of galaxy formation, with typical DLA proper sizes larger than 20 kpc in host halos of masses ∼ 10{sup 12}M{sub ☉}. We infer that typical galaxies at z ≅ 2 to 3 are surrounded by systems of atomic clouds that are much more extended than the luminous parts of galaxies and contain ∼ 10% of the baryons in the host halo.

  5. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    International Nuclear Information System (INIS)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora

    2017-01-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N fluid , will be improved by an order of magnitude compared to current bounds.

  6. Clustering of galaxies near damped Lyman-alpha systems with (z) = 2.6

    Science.gov (United States)

    Wolfe, A. M

    1993-01-01

    The galaxy two-point correlation function, xi, at (z) = 2.6 is determined by comparing the number of Ly-alpha-emitting galaxies in narrowband CCD fields selected for the presence of damped L-alpha absorption to their number in randomly selected control fields. Comparisons between the presented determination of (xi), a density-weighted volume average of xi, and model predictions for (xi) at large redshifts show that models in which the clustering pattern is fixed in proper coordinates are highly unlikely, while better agreement is obtained if the clustering pattern is fixed in comoving coordinates. Therefore, clustering of Ly-alpha-emitting galaxies around damped Ly-alpha systems at large redshifts is strong. It is concluded that the faint blue galaxies are drawn from a parent population different from normal galaxies, the presumed offspring of damped Ly-alpha systems.

  7. Wandering in the Lyman-alpha forest: a study of dark matter-dark radiation interactions

    Energy Technology Data Exchange (ETDEWEB)

    Krall, Rebecca; Cyr-Racine, Francis-Yan; Dvorkin, Cora, E-mail: rkrall@physics.harvard.edu, E-mail: fcyrraci@physics.harvard.edu, E-mail: dvorkin@physics.harvard.edu [Harvard University, Department of Physics, Cambridge, MA 02138 (United States)

    2017-09-01

    The amplitude of large-scale matter fluctuations inferred from the observed Sunyaev-Zeldovich (SZ) cluster mass function and from weak gravitational lensing studies, when taken at face value, is in tension with measurements of the cosmic microwave background (CMB) and baryon acoustic oscillation (BAO). In this work, we revisit whether this possible discrepancy can be attributed to new interactions in the dark matter sector. Focusing on a cosmological model where dark matter interacts with a dark radiation species until the epoch of matter-radiation equality, we find that measurements of the Lyman-alpha flux power spectrum from the Sloan Digital Sky Survey provide no support to the hypothesis that new dark matter interactions can resolve the possible tension between CMB and large-scale structure (LSS). Indeed, while the addition of dark matter-dark radiation interactions leads to an improvement of 2ΔlnL=12 with respect to the standard Λ cold dark matter (ΛCDM) model when only CMB, BAO, and LSS data are considered, the inclusion of Lyman-alpha data reduces the improvement of the fit to 2ΔlnL=6 relative to ΛCDM . We thus conclude that the statistical evidence for new dark matter interactions (largely driven by the Planck SZ dataset) is marginal at best, and likely caused by systematics in the data. We also perform a Fisher forecast analysis for the reach of a future dataset composed of a CMB-S4 experiment combined with the Large Synoptic Survey Telescope galaxy survey. We find that the constraint on the effective number of fluid-like dark radiation species, Δ N {sub fluid}, will be improved by an order of magnitude compared to current bounds.

  8. Isotope effect in the photochemical decomposition of CO{sub 2} (ice) by Lyman-{alpha} radiation

    Energy Technology Data Exchange (ETDEWEB)

    Yuan Chunqing; Yates, John T. Jr. [Department of Chemistry, University of Virginia, Charlottesville, Virginia 22904 (United States)

    2013-04-21

    The photochemical decomposition of CO{sub 2}(ice) at 75 K by Lyman-{alpha} radiation (10.2 eV) has been studied using transmission infrared spectroscopy. An isotope effect in the decomposition of the CO{sub 2} molecule in the ice has been discovered, favoring {sup 12}CO{sub 2} photodecomposition over {sup 13}CO{sub 2} by about 10%. The effect is caused by electronic energy transfer from the excited CO{sub 2} molecule to the ice matrix, which favors quenching of the heavier electronically-excited {sup 13}CO{sub 2} molecule over {sup 12}CO{sub 2}. The effect is similar to the Menzel-Gomer-Redhead isotope effect in desorption from adsorbed molecules on surfaces when electronically excited. An enhancement of the rate of formation of lattice-trapped CO and CO{sub 3} species is observed for the photolysis of the {sup 12}CO{sub 2} molecule compared to the {sup 13}CO{sub 2} molecule in the ice. Only 0.5% of the primary photoexcitation results in O-CO bond dissociation to produce trapped-CO and trapped-CO{sub 3} product molecules and the majority of the electronically-excited CO{sub 2} molecules return to the ground state. Here either vibrational relaxation occurs (majority process) or desorption of CO{sub 2} occurs (minority process) from highly vibrationally-excited CO{sub 2} molecules in the ice. The observation of the {sup 12}C/{sup 13}C isotope effect in the Lyman-{alpha} induced photodecomposition of CO{sub 2} (ice) suggests that over astronomical time scales the isotope enrichment effect may distort historical information derived from isotope ratios in space wherever photochemistry can occur.

  9. Oxygen sensitivity of krypton and Lyman-alpha hygrometers

    NARCIS (Netherlands)

    Dijk, van A.; Kohsiek, W.; Bruin, de H.A.R.

    2003-01-01

    The oxygen sensitivity of krypton and Lyman-¿ hygrometers is studied. Using a dewpoint generator and a controlled nitrogen/oxygen flow the extinction coefficients of five hygrometers associated with the third-order Taylor expansion of the Lambert¿Beer law around reference conditions for oxygen and

  10. Constraining the Intergalactic and Circumgalactic Media with Lyman-Alpha Absorption

    Science.gov (United States)

    Sorini, Daniele; Onorbe, Jose; Hennawi, Joseph F.; Lukic, Zarija

    2018-01-01

    Lyman-alpha (Ly-a) absorption features detected in quasar spectra in the redshift range 02Mpc, the simulations asymptotically match the observations, because the ΛCDM model successfully describes the ambient IGM. This represents a critical advantage of studying the mean absorption profile. However, significant differences between the simulations, and between simulations and observations are present on scales 20kpc-2Mpc, illustrating the challenges of accurately modeling and resolving galaxy formation physics. It is noteworthy that these differences are observed as far out as ~2Mpc, indicating that the `sphere-of-influence' of galaxies could extend to approximately ~20 times the halo virial radius (~100kpc). Current observations are very precise on these scales and can thus strongly discriminate between different galaxy formation models. I demonstrate that the Ly-a absorption profile is primarily sensitive to the underlying temperature-density relationship of diffuse gas around galaxies, and argue that it thus provides a fundamental test of galaxy formation models. With near-future high-precision observations of Ly-a absorption, the tools developed in my thesis set the stage for even stronger constraints on models of galaxy formation and cosmology.

  11. Lyman series profiles: From laser-plasmas to white dwarf stars

    Energy Technology Data Exchange (ETDEWEB)

    Kielkopf, J.F. [University of Louisville, Louisville, Kentucky 40292 (United States); Allard, N.F. [Observatoire de Paris-Meudon, France and Institut d Astrophysique, Paris (France)

    1999-04-01

    The low energy interactions of neutral and ionized hydrogen atoms are fundamental processes which also have important applications to the diagnostics of laboratory and astrophysical plasmas. Satellites in the far wings of Lyman {alpha} and Lyman {beta} have been identified as ultraviolet absorption features in the spectra of white dwarf and {lambda} Bootis stars, and they are seen in the emission spectra of plasmas produced when a pulsed laser excites a target H{sub 2} gas. The observed Lyman series profiles agree with unified line shape theory which includes variation of the dipole transition moment during the radiative collision. {copyright} {ital 1999 American Institute of Physics.}

  12. Probing HeII Reionization at z>3.5 with Resolved HeII Lyman Alpha Forest Spectra

    Science.gov (United States)

    Worseck, Gabor

    2017-08-01

    The advent of GALEX and COS have revolutionized our view of HeII reionization, the final major phase transition of the intergalactic medium. COS spectra of the HeII Lyman alpha forest have confirmed with high confidence the high HeII transmission that signifies the completion of HeII reionization at z 2.7. However, the handful of z>3.5 quasars observed to date show a set of HeII transmission 'spikes' and larger regions with non-zero transmission that suggest HeII reionization was well underway by z=4. This is in striking conflict with predictions from state-of-the-art radiative transfer simulations of a HeII reionization driven by bright quasars. Explaining these measurements may require either faint quasars or more exotic sources of hard photons at z>4, with concomitant implications for HI reionization. However, many of the observed spikes are unresolved in G140L spectra and are significantly impacted by Poisson noise. Current data cannot reliably probe the ionization state of helium at z>3.5.We request 41 orbits to obtain science-grade G130M spectra of the two UV-brightest HeII-transmitting QSOs at z>3.5 to confirm and resolve their HeII transmission spikes as an unequivocal test of early HeII reionization. These spectra are complemented by recently obtained data from 8m telescopes: (1) Echelle spectra of the coeval HI Lya forest to map the underlying density field that modulates the HeII absorption, and (2) Our dedicated survey for foreground QSOs that may source the HeII transmission. Our recent HST programs revealed the only two viable targets to resolve the z>3.5 HeII Lyman alpha forest, and to conclusively solve this riddle.

  13. Resonance-enhanced two-photon ionization of ions by Lyman alpha radiation in gaseous nebulae.

    Science.gov (United States)

    Johansson, S; Letokhov, V

    2001-01-26

    One of the mysteries of nebulae in the vicinity of bright stars is the appearance of bright emission spectral lines of ions, which imply fairly high excitation temperatures. We suggest that an ion formation mechanism, based on resonance-enhanced two-photon ionization (RETPI) by intense H Lyman alpha radiation (wavelength of 1215 angstroms) trapped inside optically thick nebulae, can produce these spectral lines. The rate of such an ionization process is high enough for rarefied gaseous media where the recombination rate of the ions formed can be 10(-6) to 10(-8) per second for an electron density of 10(3) to 10(5) per cubic centimeter in the nebula. Under such conditions, the photo-ions formed may subsequently undergo further RETPI, catalyzed by intense He i and He ii radiation, which also gets enhanced in optically thick nebulae that contain enough helium.

  14. Lyman-alpha transit observations of the warm rocky exoplanet GJ1132b

    Science.gov (United States)

    Waalkes, William; Berta-Thompson, Zachory K.; Charbonneau, David; Irwin, Jonathan; Newton, Elisabeth; Dittmann, Jason; Bourrier, Vincent; Ehrenreich, David; Kempton, Eliza; Will

    2018-06-01

    GJ1132b is one of the few known Earth-sized planets, and at 12pc away it is also one of the closest known transiting planets. With an equilibrium temperature of 500 K, this planet is too hot to be habitable but we can use it to learn about the presence and volatile content of rocky planet atmospheres around M dwarf stars. Using Hubble STIS spectra obtained during primary transit, we search for a Lyman-α transit. If we were to observe a deep Lyman-α transit, that would indicate the presence of a neutral hydrogen envelope flowing from GJ1132b. On the other hand, ruling out deep absorption from neutral hydrogen may indicate that this planet has either retained its volatiles or lost them very early in the star’s life. We carry out this analysis by extracting 1D spectra from the STIS pipeline, splitting the time-tagged spectra into higher resolution samples, and producing light curves of the red and blue wings of the Lyman-α line. We fit for the baseline stellar flux and transit depths in order to constrain the characteristics of the cloud of neutral hydrogen gas that may surround the planet. We do not conclusively detect a transit but the results provide an upper limit for the transit depth. We also analyze the stellar variability and Lyman-α spectrum of GJ1132, a slowly-rotating 0.18 solar mass M dwarf with previously uncharacterized UV activity. Understanding the role that UV variability plays in planetary atmospheres and volatile retention is crucial to assess atmospheric evolution and the habitability of cooler rocky planets.

  15. An intensity monitor for solar hydrogen Lyman-alpha radiation (TAIYO SXU)

    International Nuclear Information System (INIS)

    Oshio, Takanori; Masuoka, Toshio; Higashino, Ichiro; Watanabe, Norihiko.

    1975-01-01

    The absolute intensity of hydrogen Lyman-alpha (1216A) from the total solar disk is currently monitored by an ion chamber as a part of the satellite mission of TAIYO. The apparatus consists of an ion chamber with a special input control mask and associated electronics. The ion chamber with an MgF 2 window and filled with NO gas is sensitive to a narrow spectral band including the Lα. The special mask serves to keep the angular response of the detector constant at the elevation angle of the sun relative to the plane perpendicular to the spinning axis of the satellite within an error of the order of one percent, when the angle is within +-30 0 . A flux reducer attenuates the incident radiation upon the detector by a factor of 20 to lengthen the life of detector. The associated electronics measures the output current of the ion chamber, holds the maximum value of the output every four-second period and sends it to the telemeter. From the currently observed data, the absolute intensity of the solar Lα is 3.2 x 10 11 photons/cm 2 sec and constant within +-4.2% during the period from 24 February to 31 May, 1975. (auth.)

  16. Characterizing the Lyman-alpha forest flux probability distribution function using Legendre polynomials

    Science.gov (United States)

    Cieplak, Agnieszka; Slosar, Anze

    2018-01-01

    The Lyman-alpha forest has become a powerful cosmological probe at intermediate redshift. It is a highly non-linear field with much information present beyond the power spectrum. The flux probability flux distribution (PDF) in particular has been a successful probe of small scale physics. However, it is also sensitive to pixel noise, spectrum resolution, and continuum fitting, all of which lead to possible biased estimators. Here we argue that measuring the coefficients of the Legendre polynomial expansion of the PDF offers several advantages over measuring the binned values as is commonly done. Since the n-th Legendre coefficient can be expressed as a linear combination of the first n moments of the field, this allows for the coefficients to be measured in the presence of noise and allows for a clear route towards marginalization over the mean flux. Additionally, in the presence of noise, a finite number of these coefficients are well measured with a very sharp transition into noise dominance. This compresses the information into a small amount of well-measured quantities. Finally, we find that measuring fewer quasars with high signal-to-noise produces a higher amount of recoverable information.

  17. NO OVERDENSITY OF LYMAN-ALPHA EMITTING GALAXIES AROUND A QUASAR AT z  ∼ 5.7

    International Nuclear Information System (INIS)

    Mazzucchelli, C.; Bañados, E.; Decarli, R.; Farina, E. P.; Venemans, B. P.; Walter, F.; Overzier, R.

    2017-01-01

    Bright quasars, observed when the universe was less than one billion years old ( z  > 5.5), are known to host massive black holes (∼10 9 M ⊙ ) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations based on the detection of Lyman-break galaxies (LBGs) around these quasars do not offer a clear picture: this may be due to the uncertain redshift constraints of LBGs, which are solely selected through broadband filters. To circumvent such uncertainties, we here perform a search for Lyman-alpha emitting galaxies (LAEs) in the field of the quasar PSO J215.1512–16.0417 at z  ∼ 5.73, through narrowband deep imaging with FORS2 at the Very Large Telescope. We study an area of 37 arcmin 2 , i.e., ∼206 comoving Mpc 2 at the redshift of the quasar. We find no evidence of an overdensity of LAEs in the quasar field with respect to blank-field studies. Possible explanations for these findings may be that our survey volume is too small, or that the strong ionizing radiation from the quasar hinders galaxy formation in its immediate proximity. Another possibility is that these quasars are not situated in the dense environments predicted by some simulations.

  18. NO OVERDENSITY OF LYMAN-ALPHA EMITTING GALAXIES AROUND A QUASAR AT z  ∼ 5.7

    Energy Technology Data Exchange (ETDEWEB)

    Mazzucchelli, C.; Bañados, E.; Decarli, R.; Farina, E. P.; Venemans, B. P.; Walter, F. [Max Planck Institute für Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Overzier, R. [Observatório Nacional, Rua José Cristino, 77. CEP 20921-400, São Cristóvão, Rio de Janeiro-RJ (Brazil)

    2017-01-01

    Bright quasars, observed when the universe was less than one billion years old ( z  > 5.5), are known to host massive black holes (∼10{sup 9} M {sub ⊙}) and are thought to reside in the center of massive dark matter overdensities. In this picture, overdensities of galaxies are expected around high-redshift quasars. However, observations based on the detection of Lyman-break galaxies (LBGs) around these quasars do not offer a clear picture: this may be due to the uncertain redshift constraints of LBGs, which are solely selected through broadband filters. To circumvent such uncertainties, we here perform a search for Lyman-alpha emitting galaxies (LAEs) in the field of the quasar PSO J215.1512–16.0417 at z  ∼ 5.73, through narrowband deep imaging with FORS2 at the Very Large Telescope. We study an area of 37 arcmin{sup 2}, i.e., ∼206 comoving Mpc{sup 2} at the redshift of the quasar. We find no evidence of an overdensity of LAEs in the quasar field with respect to blank-field studies. Possible explanations for these findings may be that our survey volume is too small, or that the strong ionizing radiation from the quasar hinders galaxy formation in its immediate proximity. Another possibility is that these quasars are not situated in the dense environments predicted by some simulations.

  19. Mechanism and computational model for Lyman-{alpha}-radiation generation by high-intensity-laser four-wave mixing in Kr-Ar gas

    Energy Technology Data Exchange (ETDEWEB)

    Louchev, Oleg A.; Saito, Norihito; Wada, Satoshi [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Bakule, Pavel [STFC, ISIS Facility, Rutherford Appleton Laboratory, Chilton, Oxfordshire OX11 0QX (United Kingdom); Yokoyama, Koji [Advanced Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 (Japan); Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan); Ishida, Katsuhiko; Iwasaki, Masahiko [Advanced Meson Science Laboratory, RIKEN Nishina Center, RIKEN, Wako, Saitama 351-0198 (Japan)

    2011-09-15

    We present a theoretical model combined with a computational study of a laser four-wave mixing process under optical discharge in which the non-steady-state four-wave amplitude equations are integrated with the kinetic equations of initial optical discharge and electron avalanche ionization in Kr-Ar gas. The model is validated by earlier experimental data showing strong inhibition of the generation of pulsed, tunable Lyman-{alpha} (Ly-{alpha}) radiation when using sum-difference frequency mixing of 212.6 nm and tunable infrared radiation (820-850 nm). The rigorous computational approach to the problem reveals the possibility and mechanism of strong auto-oscillations in sum-difference resonant Ly-{alpha} generation due to the combined effect of (i) 212.6-nm (2+1)-photon ionization producing initial electrons, followed by (ii) the electron avalanche dominated by 843-nm radiation, and (iii) the final breakdown of the phase matching condition. The model shows that the final efficiency of Ly-{alpha} radiation generation can achieve a value of {approx}5x10{sup -4} which is restricted by the total combined absorption of the fundamental and generated radiation.

  20. KECK SPECTROSCOPY OF LYMAN-BREAK GALAXIES AND ITS IMPLICATIONS FOR THE UV-CONTINUUM AND Ly{alpha} LUMINOSITY FUNCTIONS AT z > 6

    Energy Technology Data Exchange (ETDEWEB)

    Jiang Linhua; Egami, Eiichi; Walth, Gregory [Steward Observatory, University of Arizona, 933 North Cherry Avenue, Tucson, AZ 85721 (United States); Kashikawa, Nobunari [Optical and Infrared Astronomy Division, National Astronomical Observatory, Mitaka, Tokyo 181-8588 (Japan); Matsuda, Yuichi [Department of Physics, Durham University, South Road, Durham DH1 3LE (United Kingdom); Shimasaku, Kazuhiro [Department of Astronomy, University of Tokyo, Hongo, Tokyo 113-0033 (Japan); Nagao, Tohru [Research Center for Space and Cosmic Evolution, Ehime University, Bunkyo-cho, Matsuyama 790-8577 (Japan); Ota, Kazuaki [Department of Astronomy, Kyoto University, Kitashirakawa-Oiwake-cho, Sakyo-ku, Kyoto 606-8502 (Japan); Ouchi, Masami [Institute for Cosmic Ray Research, University of Tokyo, 5-1-5 Kashiwa-no-Ha, Kashiwa City, Chiba 77-8582 (Japan)

    2011-12-10

    We present Keck spectroscopic observations of z > 6 Lyman-break galaxy (LBG) candidates in the Subaru Deep Field (SDF). The candidates were selected as i'-dropout objects down to z' = 27 AB magnitudes from an ultra-deep SDF z'-band image. With the Keck spectroscopy we identified 19 LBGs with prominent Ly{alpha} emission lines at 6 {<=} z {<=} 6.4. The median value of the Ly{alpha} rest-frame equivalent widths (EWs) is {approx}50 A, with four EWs >100 A. This well-defined spectroscopic sample spans a UV-continuum luminosity range of -21.8 {<=} M{sub UV} {<=} -19.5 (0.6 {approx} 5 L*{sub UV}) and a Ly{alpha} luminosity range of (0.3-3) Multiplication-Sign 10{sup 43} erg s{sup -1} (0.3-3 L*{sub Ly{alpha}}). We derive the UV and Ly{alpha} luminosity functions (LFs) from our sample at (z) {approx} 6.2 after we correct for sample incompleteness. We find that our measurement of the UV LF is consistent with the results of previous studies based on photometric LBG samples at 5 < z < 7. Our Ly{alpha} LF is also generally in agreement with the results of Ly{alpha}-emitter surveys at z {approx} 5.7 and 6.6. This study shows that deep spectroscopic observations of LBGs can provide unique constraints on both the UV and Ly{alpha} LFs at z > 6.

  1. Discovery of Ubiquitous Fast-Propagating Intensity Disturbances by the Chromospheric Lyman Alpha Spectropolarimeter (CLASP)

    Science.gov (United States)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.; Auchère, F.; Trujillo Bueno, J.; Asensio Ramos, A.; Štěpán, J.; Belluzzi, L.; Manso Sainz, R.; De Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.

    2016-12-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Lyα line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s-1, and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  2. DISCOVERY OF UBIQUITOUS FAST-PROPAGATING INTENSITY DISTURBANCES BY THE CHROMOSPHERIC LYMAN ALPHA SPECTROPOLARIMETER (CLASP)

    International Nuclear Information System (INIS)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G.; Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T.; Winebarger, A.; Kobayashi, K.; Cirtain, J.; Champey, P.; Auchère, F.; Bueno, J. Trujillo; Ramos, A. Asensio

    2016-01-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Ly α line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s −1 , and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  3. DISCOVERY OF UBIQUITOUS FAST-PROPAGATING INTENSITY DISTURBANCES BY THE CHROMOSPHERIC LYMAN ALPHA SPECTROPOLARIMETER (CLASP)

    Energy Technology Data Exchange (ETDEWEB)

    Kubo, M.; Katsukawa, Y.; Suematsu, Y.; Kano, R.; Bando, T.; Narukage, N.; Ishikawa, R.; Hara, H.; Giono, G. [National Astronomical Observatory of Japan, National Institutes of Natural Sciences, 2-21-1 Osawa, Mitaka, Tokyo 181-8588 (Japan); Tsuneta, S.; Ishikawa, S.; Shimizu, T.; Sakao, T. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, Chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Winebarger, A.; Kobayashi, K.; Cirtain, J. [NASA Marshall Space Flight Center, ZP 13, Huntsville, AL 35812 (United States); Champey, P. [University of Alabama in Huntsville, 301 Sparkman Drive, Huntsville, AL 35899 (United States); Auchère, F. [Institut d’Astrophysique Spatiale, CNRS/Univ. Paris-Sud 11, Bâtiment 121, F-91405 Orsay (France); Bueno, J. Trujillo; Ramos, A. Asensio, E-mail: masahito.kubo@nao.ac.jp [Instituto de Astrofísica de Canarias, E-38205 La Laguna, Tenerife (Spain); and others

    2016-12-01

    High-cadence observations by the slit-jaw (SJ) optics system of the sounding rocket experiment known as the Chromospheric Lyman Alpha Spectropolarimeter (CLASP) reveal ubiquitous intensity disturbances that recurrently propagate in either the chromosphere or the transition region or both at a speed much higher than the speed of sound. The CLASP/SJ instrument provides a time series of two-dimensional images taken with broadband filters centered on the Ly α line at a 0.6 s cadence. The multiple fast-propagating intensity disturbances appear in the quiet Sun and in an active region, and they are clearly detected in at least 20 areas in a field of view of 527″ × 527″ during the 5 minute observing time. The apparent speeds of the intensity disturbances range from 150 to 350 km s{sup −1}, and they are comparable to the local Alfvén speed in the transition region. The intensity disturbances tend to propagate along bright elongated structures away from areas with strong photospheric magnetic fields. This suggests that the observed fast-propagating intensity disturbances are related to the magnetic canopy structures. The maximum distance traveled by the intensity disturbances is about 10″, and the widths are a few arcseconds, which are almost determined by a pixel size of 1.″03. The timescale of each intensity pulse is shorter than 30 s. One possible explanation for the fast-propagating intensity disturbances observed by CLASP is magnetohydrodynamic fast-mode waves.

  4. The non-linear power spectrum of the Lyman alpha forest

    International Nuclear Information System (INIS)

    Arinyo-i-Prats, Andreu; Miralda-Escudé, Jordi; Viel, Matteo; Cen, Renyue

    2015-01-01

    The Lyman alpha forest power spectrum has been measured on large scales by the BOSS survey in SDSS-III at z∼ 2.3, has been shown to agree well with linear theory predictions, and has provided the first measurement of Baryon Acoustic Oscillations at this redshift. However, the power at small scales, affected by non-linearities, has not been well examined so far. We present results from a variety of hydrodynamic simulations to predict the redshift space non-linear power spectrum of the Lyα transmission for several models, testing the dependence on resolution and box size. A new fitting formula is introduced to facilitate the comparison of our simulation results with observations and other simulations. The non-linear power spectrum has a generic shape determined by a transition scale from linear to non-linear anisotropy, and a Jeans scale below which the power drops rapidly. In addition, we predict the two linear bias factors of the Lyα forest and provide a better physical interpretation of their values and redshift evolution. The dependence of these bias factors and the non-linear power on the amplitude and slope of the primordial fluctuations power spectrum, the temperature-density relation of the intergalactic medium, and the mean Lyα transmission, as well as the redshift evolution, is investigated and discussed in detail. A preliminary comparison to the observations shows that the predicted redshift distortion parameter is in good agreement with the recent determination of Blomqvist et al., but the density bias factor is lower than observed. We make all our results publicly available in the form of tables of the non-linear power spectrum that is directly obtained from all our simulations, and parameters of our fitting formula

  5. Lyman Alpha Camera for Io's SO2 atmosphere and Europa's water plumes

    Science.gov (United States)

    McEwen, Alfred S.; Sandel, Bill; Schneider, Nick

    2014-05-01

    The Student Lyman-Alpha Mapper (SLAM) was conceived for the Io Volcano Observer (IVO) mission proposal (McEwen et al., 2014) to determine the spatial and temporal variations in Io's SO2 atmosphere by recording the H Ly-α reflection over the disk (Feldman et al., 2000; Feaga et al., 2009). SO2 absorbs at H Ly-α, thereby modulating the brightness of sunlight reflected by the surface, and measures the density of the SO2 atmosphere and its variability with volcanic activity and time of day. Recently, enhancements at the Ly-α wavelength (121.57 nm) were seen near the limb of Europa and interpreted as active water plumes ~200 km high (Roth et al., 2014). We have a preliminary design for a very simple camera to image in a single bandpass at Ly-α, analogous to a simplified version of IMAGE EUV (Sandel et al. 2000). Our goal is at least 50 resolution elements across Io and/or Europa (~75 km/pixel), ~3x better than HST STIS, to be acquired at a range where the radiation noise is below 1E-4 hits/pixel/s. This goal is achieved with a Cassegrain-like telescope with a 10-cm aperture. The wavelength selection is achieved using a simple self-filtering mirror in combination with a solar-blind photocathode. A photon-counting detector based on a sealed image intensifier preserves the poisson statistics of the incoming photon flux. The intensifier window is coated with a solar-blind photocathode material (CsI). The location of each photon event is recorded by a position-sensitive anode based on crossed delay-line or wedge-and-strip technology. The sensitivity is 0.01 counts/pixel/sec/R, sufficient to estimate SO2 column abundances ranging from 1E15 to 1E17 per cm2 in a 5 min (300 sec) exposure. Sensitivity requirements to search for and image Europa plumes may be similar. Io's Ly-α brightness of ~3 kR exceeds the 0.8 kR brightness of Europa's plume reported by Roth et al. (2014), but the plume brightness is a direct measurement rather than inferring column abundance from

  6. LYMAN : a new window on the universe

    International Nuclear Information System (INIS)

    Dopita, M.A.; Tuohy, I.R.; Mathewson, D.S.; Hunstead, R.W.; Waterworth, M.D.

    1988-01-01

    This document is the final Phase A Science Report of the Australian LYMAN Science Working Group, and describes in detail the scientific objectives, technical feasibility, and engineering implementation of the LYMAN mission as developed in the Australian studies. LYMAN represents the next generation, high-orbit, UV space observatory, and is designed to operate over the wavelength range λ 100 - 1900 Angstrom. The prime spectral range is λ 900 - 1250 Angstrom, which will be covered at a resolution of λ/Δ λ = 30000, and the sensitivity of the instrumentation will be orders of magnitude better than previous missions. In this region we find the Lyman series of molecular and atomic hydrogen, as well as a whole host of atomic and ionic lines of great diagnostic power. LYMAN will be able to accomplish uniquely valuable astrophysics as a result, and will be applied to the study of all types of astronomical targets in the fields of cosmology, galactic research, the interstellar medium, stars in all stages of their evolution, and to particular solar system objects. The LYMAN Mission was the subject of a $1M study contract awarded by the Australian Space Office, a section of DITAC, to Auspace Pty. Ltd. The Phase A study was conduced in parallel with the ESA Phase A Study, and with a strong scientific and technical liaison between the two groups. LYMAN is now likely to be launched as a joint ESA/NASA project, but the future Australian role in the mission, as determined by current policy, would be minimal. Australia would therefore be effectively locked out of the very exciting front-line science described in this document, and the valuable university - industry liaison that has been developed over the last eight years will be lost

  7. Lyman Alpha Searches at Redshift Z>7

    Science.gov (United States)

    Willis, Jon

    2007-05-01

    The ZEN survey is a narrow J-band survey for Ly-alpha emitting galaxies at z > 7. I will briefly review the pros and cons of narrow band observations before summarising the ZEN1 and ZEN2 searches based upon deep ISAAC pointings. I will then present ZEN3, consisting of wide field, narrow band observations of two fields using the CFHT WIRCam facility. I will conclude by reviewing the current sample of candidates and what we have learned about the z > 7 Ly-alpha emitting population.

  8. Isolating the Lyman alpha forest BAO anomaly

    Energy Technology Data Exchange (ETDEWEB)

    Evslin, Jarah, E-mail: jarah@impcas.ac.cn [Institute of Modern Physics, Chinese Academy of Sciences, NanChangLu 509, Lanzhou 730000 (China)

    2017-04-01

    A 2.5-3σ discrepancy has been reported between the baryonic acoustic oscillation peak (BAO) in the Lyman α forest at z ∼ 2.34 and the best fit Planck ΛCDM cosmology. To isolate the origin of the tension, we consider unanchored BAO, in which the standard BAO ruler is not calibrated, eliminating any dependence on cosmology before redshift z ∼ 2.34. We consider BOSS BAO measurements at z ∼ 0.32, 0.57 and 2.34, using the full 2-dimensional constraints on the angular and line of sight BAO scale, as well as isotropic BAO measurements by 6dF and SDSS at z ∼ 0.106 and z ∼ 0.15. We find that the z >0.43 data alone is in 2.9σ of tension with ΛCDM with or without the Planck best fit values of the mass fraction Ω {sub m} and the BAO scale r {sub d} H {sub 0}, indicating that the tension arises not from the ΛCDM parameters but from the dark energy evolution itself at 0.57< z <2.34. This conclusion is supported when the acoustic scale measured by the CMB is included, which further increases the tension and excludes a solution with a constant dark energy equation of state. Including the low z BAO data, which is itself consistent with ΛCDM, reduces the tension to just over 2σ, however in this case a CPL parametrization of the dark energy evolution yields only a modest improvement.

  9. Bias of damped Lymansystems from their cross-correlation with CMB lensing

    Science.gov (United States)

    Alonso, D.; Colosimo, J.; Font-Ribera, A.; Slosar, A.

    2018-04-01

    We cross-correlate the positions of damped Lymansystems (DLAs) and their parent quasar catalog with a convergence map derived from the Planck cosmic microwave background (CMB) temperature data. We make consistent measurements of the lensing signal of both samples in both Fourier and configuration space. By interpreting the excess signal present in the DLA catalog with respect to the parent quasar catalog as caused by the large scale structure traced by DLAs, we are able to infer the bias of these objects: bDLA=2.6±0.9. These results are consistent with previous measurements made in cross-correlation with the Lyman-α forest, although the current noise in the lensing data and the low number density of DLAs limits the constraining power of this measurement. We discuss the robustness of the analysis with respect to a number different systematic effects and forecast prospects of carrying out this measurement with data from future experiments.

  10. Hydrogen Balmer alpha intensity distributions and line profiles from multiple scattering theory using realistic geocoronal models

    Science.gov (United States)

    Anderson, D. E., Jr.; Meier, R. R.; Hodges, R. R., Jr.; Tinsley, B. A.

    1987-01-01

    The H Balmer alpha nightglow is investigated by using Monte Carlo models of asymmetric geocoronal atomic hydrogen distributions as input to a radiative transfer model of solar Lyman-beta radiation in the thermosphere and atmosphere. It is shown that it is essential to include multiple scattering of Lyman-beta radiation in the interpretation of Balmer alpha airglow data. Observations of diurnal variation in the Balmer alpha airglow showing slightly greater intensities in the morning relative to evening are consistent with theory. No evidence is found for anything other than a single sinusoidal diurnal variation of exobase density. Dramatic changes in effective temperature derived from the observed Balmer alpha line profiles are expected on the basis of changing illumination conditions in the thermosphere and exosphere as different regions of the sky are scanned.

  11. Impact of Lyman alpha pressure on metal-poor dwarf galaxies

    Science.gov (United States)

    Kimm, Taysun; Haehnelt, Martin; Blaizot, Jérémy; Katz, Harley; Michel-Dansac, Léo; Garel, Thibault; Rosdahl, Joakim; Teyssier, Romain

    2018-04-01

    Understanding the origin of strong galactic outflows and the suppression of star formation in dwarf galaxies is a key problem in galaxy formation. Using a set of radiation-hydrodynamic simulations of an isolated dwarf galaxy embedded in a 1010 M⊙ halo, we show that the momentum transferred from resonantly scattered Lyman-α (Lyα) photons is an important source of stellar feedback which can shape the evolution of galaxies. We find that Lyα feedback suppresses star formation by a factor of two in metal-poor galaxies by regulating the dynamics of star-forming clouds before the onset of supernova explosions (SNe). This is possible because each Lyα photon resonantly scatters and imparts ˜10-300 times greater momentum than in the single scattering limit. Consequently, the number of star clusters predicted in the simulations is reduced by a factor of ˜5, compared to the model without the early feedback. More importantly, we find that galactic outflows become weaker in the presence of strong Lyα radiation feedback, as star formation and associated SNe become less bursty. We also examine a model in which radiation field is arbitrarily enhanced by a factor of up to 10, and reach the same conclusion. The typical mass-loading factors in our metal-poor dwarf system are estimated to be ˜5-10 near the mid-plane, while it is reduced to ˜1 at larger radii. Finally, we find that the escape of ionizing radiation and hence the reionization history of the Universe is unlikely to be strongly affected by Lyα feedback.

  12. Far-UV Spectral Mapping of Lunar Composition, Porosity, and Space Weathering: LRO Lyman Alpha Mapping Project (LAMP)

    Science.gov (United States)

    Retherford, K. D.; Greathouse, T. K.; Mandt, K.; Gladstone, R.; Liu, Y.; Hendrix, A. R.; Hurley, D.; Cahill, J. T.; Stickle, A. M.; Egan, A.; Kaufmann, D. E.; Grava, C.; Pryor, W. R.

    2016-12-01

    Far ultraviolet reflectance measurements of the Moon, icy satellites, comets, and asteroids obtained within the last decade have ushered in a new era of scientific advancement for UV surface investigations. The Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP) has demonstrated an innovative nightside observing technique, putting a new light on permanently shadowed regions (PSRs) and other features on the Moon. Dayside far-UV albedo maps complement the nightside data, and LRO's polar orbit and high data downlink capabilities enable searches for diurnal variations in spectral signals. We'll discuss the strengths of the far-UV reflectance imaging spectroscopy technique with respect to several new LAMP results. Detections of water frost and hydration signatures near 165 nm, for example, provide constraints on composition that complement infrared spectroscopy, visible imaging, neutron spectroscopy, radar, and other techniques. At far-UV wavelengths a relatively blue spectral slope is diagnostic of space weathering, which is opposite of the spectral reddening indicator of maturity at wavelengths longward of 180 nm. By utilizing natural diffuse illumination sources on the nightside the far-UV technique is able to identify relative increases in porosity within the PSRs, and provides an additional tool for determining relative surface ages. Prospects for future studies are further enabled by a new, more sensitive dayside operating mode enacted during the present LRO mission extension.

  13. Damped Lyman-alpha absorption by disk galaxies with large redshifts. III. Intermediate-resolution spectroscopy

    International Nuclear Information System (INIS)

    Turnshek, D.A.; Wolfe, A.M.; Lanzetta, K.M.; Briggs, F.H.; Cohen, R.D.

    1989-01-01

    New intermediate-resolution spectroscopy for six members of a sample of 68 moderate- to high-redshift QSOs is presented. Evidence is reported which indicates that seven strong absorption features in the QSO spectra are due to damped Ly-alpha absorption. A standard curve-of-growth analysis on five of the damped systems is performed, and relevant properties are tabulated and discussed. Six of the seven damped Ly-alpha systems have H I column densities of 2 x 10 to the 20th/sq cm or larger, while the remaining system has an H I column density of about 10 to the 20th/sq cm. It is suggested that damped Ly-alpha systems arise when a sight line intercepts a high-redshift protogalaxy disk containing a quiescent cloud component characterized by high column density and low effective velocity dispersion. At the same time, the sight line usually intercepts a broader turbulent component, which is identified as the halo, characterized by much lower column density and higher effective velocity dispersion. 42 refs

  14. Development of a Lyman-α Imaging Solar Telescope for the Satellite

    Directory of Open Access Journals (Sweden)

    M. Jang

    2005-09-01

    Full Text Available Long term observations of full-disk Lyman-α irradiance have been made by the instruments on various satellites. In addition, several sounding rockets dating back to the 1950s and up through the present have measured the Lyman-α irradiance. Previous full disk Lyman-α images of the sun have been very interesting and useful scientifically, but have been only five-minute ``snapshots" obtained on sounding rocket flights. All of these observations to date have been snapshots, with no time resolution to observe changes in the chromospheric structure as a result of the evolving magnetic field, and its effect on the Lyman-α intensity. The Lyman-α Imaging Solar Telescope(LIST can provide a unique opportunity for the study of the sun in the Lyman-α region with the high time and spatial resolution for the first time. Up to the 2nd year development, the preliminary design of the optics, mechanical structure and electronics system has been completed. Also the mechanical structure analysis, thermal analysis were performed and the material for the structure was chosen as a result of these analyses. And the test plan and the verification matrix were decided. The operation systems, technical and scientific operation, were studied and finally decided. Those are the technical operation, mechanical working modes for the observation and safety, the scientific operation and the process of the acquired data. The basic techniques acquired through the development of satellite based solar telescope are essential for the construction of space environment forecast system in the future. The techniques which we developed through this study, like mechanical, optical and data processing techniques, could be applied extensively not only to the process of the future production of flight models of this kind, but also to the related industries. Also, we can utilize the scientific achievements which are obtained throughout the project. And these can be utilized to build a high

  15. LRO Lyman Alpha Mapping Project (LAMP) Far-UV Investigations of Lunar Composition, Porosity, and Space Weathering

    Science.gov (United States)

    Retherford, K. D.; Greathouse, T. K.; Mandt, K. E.; Gladstone, R.; Hendrix, A.; Cahill, J. T.; Liu, Y.; Grava, C.; Hurley, D.; Egan, A.; Kaufmann, D. E.; Raut, U.; Byron, B. D.; Magana, L. O.; Stickle, A. M.; Wyrick, D. Y.; Pryor, W. R.

    2017-12-01

    Far ultraviolet reflectance measurements of the Moon, icy satellites, comets, and asteroids have proven surprisingly useful for advancing our understanding of planetary surfaces. This new appreciation for planetary far-UV imaging spectroscopy is provided in large part thanks to nearly a decade of investigations with the Lunar Reconnaissance Orbiter (LRO) Lyman Alpha Mapping Project (LAMP). LAMP has demonstrated an innovative nightside observing technique, putting a new light on permanently shadowed regions (PSRs) and other features on the Moon. Dayside far-UV albedo maps complement the nightside data, enabling comparisons of direct and hemispheric (diffuse) illumination derived albedos. We'll discuss the strengths of the far-UV reflectance imaging spectroscopy technique with respect to several new LAMP results. Detections of water frost and hydration signatures near 165 nm, for example, provide constraints on composition that complement infrared spectroscopy, visible imaging, neutron spectroscopy, radar, and other techniques. LRO's polar orbit and high data downlink capabilities enable searches for diurnal variations in spectral signals. At far-UV wavelengths a relatively blue spectral slope is diagnostic of space weathering, which is opposite of the spectral reddening indicator of maturity at wavelengths longward of 180 nm. By utilizing natural diffuse illumination sources on the nightside the far-UV technique is able to identify relative increases in porosity within the PSRs, and provides an additional tool for determining relative surface ages. On October 6, 2016 LAMP enacted a new, more sensitive dayside operating mode that expands its ability to search for diurnally varying hydration signals associated with different regions and features.

  16. Constraints on Neutral Hydrogen Outflow from the Warm Rocky Planet GJ1132b using Lyman-alpha Transit Observations

    Science.gov (United States)

    Waalkes, William; Berta-Thompson, Zachory; Charbonneau, David; Irwin, Jonathan; Newton, Elisabeth; Dittmann, Jason; Bourrier, Vincent; Ehrenreich, David; Kempton, Eliza

    2018-01-01

    GJ1132b is one of the few known Earth-sized planets, and at 12 pc away it is also one of the closest known transiting planets. With an equilibrium temperature of 500 K, this planet is too hot to be habitable but we can use it to learn about the presence and volatile content of rocky planet atmospheres around M dwarf stars. Using Hubble STIS spectra during primary transit, we explore the potential for UV transit detections of GJ1132b. If we were to observe a deep Lyman-α transit, that would indicate the presence of a neutral hydrogen envelope flowing from GJ1132b. On the other hand, ruling out deep absorption from neutral hydrogen may indicate that this planet has either retained its volatiles or lost them very early in the star’s life. We carry out this analysis by extracting 1D spectra from the STIS pipeline, splitting the time-tagged spectra into higher resolution samples, and producing light curves of the red and blue wings of the Lyman-α line. We fit for the baseline stellar flux and transit depths in order to constrain the characteristics of the cloud of neutral hydrogen gas that may surround the planet. Our work extends beyond the transit study into an analysis of the stellar variability and Lyman-α spectrum of GJ1132, a slowly-rotating 0.18 MSun M dwarf with previously uncharacterized UV activity. Understanding the role that UV variability plays in planetary atmospheres and volatile retention is crucial to assess atmospheric evolution and the habitability of cooler rocky planets.

  17. Analysis of coronal H I Lyman alpha measurements from a rocket flight on 1979 April 13

    International Nuclear Information System (INIS)

    Withbroe, G.L.; Kohl, J.L.; Weiser, H.; Noci, G.; Munro, R.H.

    1982-01-01

    Measurements of the profiles of resonantly scattered hydrogen Lyman-α coronal radiation have been used to determine hydrogen kinetic temperatures from 1.5 to 4 R/sub sun/ from Sun center in a quiet region of the corona. Proton temperatures derived from the line widths decrease with height from 2.6 x 10 6 K at r = 1.5 R/sub sun/ to 1.2 x 10 6 K at r = 4 R/sub sun/. These measurements combined with temperatures for lower heights determined from earlier Skylab and eclipse data suggest that there is a maximum in the quiet coronal proton temperature at about 1.5 R/sub sun/. Comparison of measured Lyman-α intensities with those calculated using a representative model for the radial variation of the coronal electron density provides information on the magnitude of the electron temperature gradient and suggests that the solar wind flow was subsonic for r<4 R/sub sun/ in the observed region. Comparison of the measured kinetic temperatures to the predictions of a simple two fluid model suggests that there is a small amount of proton heating and/or a nonthermal contribution to the motions of coronal protons between 1.5 and 4 R/sub sun/

  18. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    Energy Technology Data Exchange (ETDEWEB)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger [Department of Astronomy, Oskar Klein Centre, Stockholm University, AlbaNova University Centre, SE-106 91 Stockholm (Sweden); Adamo, Angela [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Schaerer, Daniel [Université de Toulouse, UPS-OMP, IRAP, F-31000 Toulouse (France); Verhamme, Anne; Orlitová, Ivana [Geneva Observatory, University of Geneva, 51 Chemin des Maillettes, CH-1290 Versoix (Switzerland); Mas-Hesse, J. Miguel; Otí-Floranes, Héctor [Centro de Astrobiología (CSIC-INTA), Departamento de Astrofísica, P.O. Box 78, E-28691 Villanueva de la Cañada (Spain); Cannon, John M.; Pardy, Stephen [Department of Physics and Astronomy, Macalester College, 1600 Grand Avenue, Saint Paul, MN 55105 (United States); Atek, Hakim [Laboratoire dAstrophysique, École Polytechnique Fédérale de Lausanne (EPFL), Observatoire, CH-1290 Sauverny (Switzerland); Kunth, Daniel [Institut d' Astrophysique de Paris, UMR 7095, CNRS and UPMC, 98 bis Bd Arago, F-75014 Paris (France); Laursen, Peter [Dark Cosmology Centre, Niels Bohr Institute, University of Copenhagen, Juliane Maries Vej 30, DK-2100 Copenhagen (Denmark); Herenz, E. Christian, E-mail: matthew@astro.su.se [Leibniz-Institut für Astrophysik (AIP), An der Sternwarte 16, D-14482 Potsdam (Germany)

    2014-02-10

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f{sub esc}{sup Lyα} of 80%; such objects have not previously been reported at low-z.

  19. The Lyman alpha reference sample. II. Hubble space telescope imaging results, integrated properties, and trends

    International Nuclear Information System (INIS)

    Hayes, Matthew; Östlin, Göran; Duval, Florent; Sandberg, Andreas; Guaita, Lucia; Melinder, Jens; Rivera-Thorsen, Thøger; Adamo, Angela; Schaerer, Daniel; Verhamme, Anne; Orlitová, Ivana; Mas-Hesse, J. Miguel; Otí-Floranes, Héctor; Cannon, John M.; Pardy, Stephen; Atek, Hakim; Kunth, Daniel; Laursen, Peter; Herenz, E. Christian

    2014-01-01

    We report new results regarding the Lyα output of galaxies, derived from the Lyman Alpha Reference Sample, and focused on Hubble Space Telescope imaging. For 14 galaxies we present intensity images in Lyα, Hα, and UV, and maps of Hα/Hβ, Lyα equivalent width (EW), and Lyα/Hα. We present Lyα and UV radial light profiles and show they are well-fitted by Sérsic profiles, but Lyα profiles show indices systematically lower than those of the UV (n ≈ 1-2 instead of ≳ 4). This reveals a general lack of the central concentration in Lyα that is ubiquitous in the UV. Photometric growth curves increase more slowly for Lyα than the far ultraviolet, showing that small apertures may underestimate the EW. For most galaxies, however, flux and EW curves flatten by radii ≈10 kpc, suggesting that if placed at high-z only a few of our galaxies would suffer from large flux losses. We compute global properties of the sample in large apertures, and show total Lyα luminosities to be independent of all other quantities. Normalized Lyα throughput, however, shows significant correlations: escape is found to be higher in galaxies of lower star formation rate, dust content, mass, and nebular quantities that suggest harder ionizing continuum and lower metallicity. Six galaxies would be selected as high-z Lyα emitters, based upon their luminosity and EW. We discuss the results in the context of high-z Lyα and UV samples. A few galaxies have EWs above 50 Å, and one shows f esc Lyα of 80%; such objects have not previously been reported at low-z.

  20. Chemical Abundances in SFG and DLA

    OpenAIRE

    Schulte-Ladbeck, Regina E.; König, Brigitte; Cherinka, Brian

    2005-01-01

    We investigate the chemical abundances of local star-forming galaxies which cause Damped Lyman Alpha lines. A metallicity versus redshift diagram is constructed, on which the chemical abundances of low-redshift star-forming galaxy populations are compared with those of high-redshift Damped Lyman Alpha systems. We disucss two types of experiments on individual star-forming galaxies. In the first, the Damped Lyman Alpha line is created against an internal ultraviolet light source generated by a...

  1. EFFECT OF HALO BIAS AND LYMAN LIMIT SYSTEMS ON THE HISTORY OF COSMIC REIONIZATION

    International Nuclear Information System (INIS)

    Kaurov, Alexander A.; Gnedin, Nickolay Y.

    2013-01-01

    We extend the existing analytical model of reionization by Furlanetto et al. to include the biasing of reionization sources and additional absorption by Lyman limit systems. Both effects enhance the original model in non-trivial ways, but do not change its qualitative features. Our model is, by construction, consistent with the observed evolution of the galaxy luminosity function at z ∼ 6 galaxies, the inadequacy of simulations and/or some of the observational constraints, or indicates an additional source of ionizing radiation at z > 8 remains to be seen.

  2. The solar ionisation rate deduced from Ulysses measurements and its implications to interplanetary Lyman alpha-intensity

    Science.gov (United States)

    Summanen, T.; Kyroelae, E.

    1995-01-01

    We have developed a computer code which can be used to study 3-dimensional and time-dependent effects of the solar cycle on the interplanetary (IP) hydrogen distribution. The code is based on the inverted Monte Carlo simulation. In this work we have modelled the temporal behaviour of the solar ionisation rate. We have assumed that during the most of the time of the solar cycle there is an anisotopic latitudinal structure but right at the solar maximum the anisotropy disappears. The effects of this behaviour will be discussed both in regard to the IP hydrogen distribution and IP Lyman a a-intensity.

  3. Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight

    Science.gov (United States)

    Walker, Salma C.; Rachmeler, Laurel; Winebarger, Amy; Champey, Patrick; Bethge, Christian

    2018-01-01

    To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to elucidate the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in Hydrogen Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this emission line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Magnesium II h & k emission lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2.

  4. Linearity Analysis and Efficiency Testing of The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) Science Cameras for Flight

    Science.gov (United States)

    Walker, S. C.; Rachmeler, L.; Winebarger, A. R.; Champey, P. R.; Bethge, C.

    2017-12-01

    To unveil the complexity of the solar atmosphere, measurement of the magnetic field in the upper chromosphere and transition region is fundamentally important, as this is where the forces transition from plasma to magnetic field dominated. Measurements of the field are also needed to shed light on the energy transport from the lower atmospheric regions to the corona beyond. Such an advance in heliospheric knowledge became possible with the first flight of the international solar sounding rocket mission, CLASP. For the first time, linear polarization was measured in H Lyman-Alpha at 121.60 nm in September 2015. For linear polarization measurements in this line, high sensitivity is required due to the relatively weak polarization signal compared to the intensity. To achieve this high sensitivity, a low-noise sensor is required with good knowledge of its characterization, including linearity. This work presents further refinement of the linearity characterization of the cameras flown in 2015. We compared the current from a photodiode in the light path to the digital response of the detectors. Pre-flight CCD linearity measurements were taken for all three flight cameras and calculations of the linear fits and residuals were performed. However, the previous calculations included a smearing pattern and a digital saturation region on the detectors which were not properly taken into account. The calculations have been adjusted and were repeated for manually chosen sub-regions on the detectors that were found not to be affected. We present a brief overview of the instrument, the calibration data and procedures, and a comparison of the old and new linearity results. The CLASP cameras will be reused for the successor mission, CLASP2, which will measure the Mg II h & k lines between 279.45 nm and 280.35 nm. The new approach will help to better prepare for and to improve the camera characterization for CLASP2.

  5. DISSECTION OF H{alpha} EMITTERS : LOW-z ANALOGS OF z > 4 STAR-FORMING GALAXIES

    Energy Technology Data Exchange (ETDEWEB)

    Shim, Hyunjin [Department of Earth Science Education, Kyungpook National University (Korea, Republic of); Chary, Ranga-Ram, E-mail: hjshim@knu.ac.kr [U.S. Planck Data Center, California Institute of Technology, MS 220-6, Pasadena, CA 91125 (United States)

    2013-03-01

    Strong H{alpha} emitters (HAEs) dominate the z {approx} 4 Lyman-break galaxy (LBG) population. We have identified local analogs of these HAEs using the Sloan Digital Sky Survey. At z < 0.4, only 0.04% of the galaxies are classified as HAEs with H{alpha} equivalent widths ({approx}> 500 A) comparable to that of z {approx} 4 HAEs. Local HAEs have lower stellar mass and lower ultraviolet (UV) luminosity than z {approx} 4 HAEs, yet the H{alpha}-to-UV luminosity ratio, as well as their specific star formation rate, is consistent with that of z {approx} 4 HAEs, indicating that they are scaled-down versions of high-z star-forming galaxies. Compared to the previously studied local analogs of LBGs selected using rest-frame UV properties, local HAEs show similar UV luminosity surface density, weaker D{sub n} (4000) break, lower metallicity, and lower stellar mass. This implies that the local HAEs are less evolved galaxies than the traditional Lyman break analogs. In the stacked spectrum, local HAEs show a significant He II {lambda}4686 emission line suggesting a population of hot, massive stars similar to that seen in some Wolf-Rayet galaxies. Low [N II]/[O III] line flux ratios imply that local HAEs are inconsistent with being systems that host bright active galactic nuclei. Instead, it is highly likely that local HAEs are galaxies with an elevated ionization parameter, either due to a high electron density or large escape fraction of hydrogen ionizing photons as in the case of Wolf-Rayet galaxies.

  6. Incorporating Single-nucleotide Polymorphisms Into the Lyman Model to Improve Prediction of Radiation Pneumonitis

    Energy Technology Data Exchange (ETDEWEB)

    Tucker, Susan L., E-mail: sltucker@mdanderson.org [Department of Bioinformatics and Computational Biology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Li Minghuan [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Xu Ting; Gomez, Daniel [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Yuan Xianglin [Department of Oncology, Tongji Hospital, Tongji Medical College, Huazhong University of Science and Technology, Wuhan (China); Yu Jinming [Department of Radiation Oncology, Shandong Cancer Hospital, Jinan, Shandong (China); Liu Zhensheng; Yin Ming; Guan Xiaoxiang; Wang Lie; Wei Qingyi [Department of Epidemiology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Mohan, Radhe [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Vinogradskiy, Yevgeniy [University of Colorado School of Medicine, Aurora, Colorado (United States); Martel, Mary [Department of Radiation Physics, University of Texas MD Anderson Cancer Center, Houston, Texas (United States); Liao Zhongxing [Department of Radiation Oncology, University of Texas MD Anderson Cancer Center, Houston, Texas (United States)

    2013-01-01

    Purpose: To determine whether single-nucleotide polymorphisms (SNPs) in genes associated with DNA repair, cell cycle, transforming growth factor-{beta}, tumor necrosis factor and receptor, folic acid metabolism, and angiogenesis can significantly improve the fit of the Lyman-Kutcher-Burman (LKB) normal-tissue complication probability (NTCP) model of radiation pneumonitis (RP) risk among patients with non-small cell lung cancer (NSCLC). Methods and Materials: Sixteen SNPs from 10 different genes (XRCC1, XRCC3, APEX1, MDM2, TGF{beta}, TNF{alpha}, TNFR, MTHFR, MTRR, and VEGF) were genotyped in 141 NSCLC patients treated with definitive radiation therapy, with or without chemotherapy. The LKB model was used to estimate the risk of severe (grade {>=}3) RP as a function of mean lung dose (MLD), with SNPs and patient smoking status incorporated into the model as dose-modifying factors. Multivariate analyses were performed by adding significant factors to the MLD model in a forward stepwise procedure, with significance assessed using the likelihood-ratio test. Bootstrap analyses were used to assess the reproducibility of results under variations in the data. Results: Five SNPs were selected for inclusion in the multivariate NTCP model based on MLD alone. SNPs associated with an increased risk of severe RP were in genes for TGF{beta}, VEGF, TNF{alpha}, XRCC1 and APEX1. With smoking status included in the multivariate model, the SNPs significantly associated with increased risk of RP were in genes for TGF{beta}, VEGF, and XRCC3. Bootstrap analyses selected a median of 4 SNPs per model fit, with the 6 genes listed above selected most often. Conclusions: This study provides evidence that SNPs can significantly improve the predictive ability of the Lyman MLD model. With a small number of SNPs, it was possible to distinguish cohorts with >50% risk vs <10% risk of RP when they were exposed to high MLDs.

  7. High-resolution Lyman-alpha filtergrams of the sun

    Science.gov (United States)

    Bonnet, R. M.; Decaudin, M.; Bruner, E. C., Jr.; Acton, L. W.; Brown, W. A.

    1980-01-01

    The results of an experiment, conducted jointly by the Lockheed Palo Alto Research Laboratory and the Laboratoire de Physique Stellaire et Planetaire du CNRS, which investigated the transition-region plasma and the geometry of coronal active regions, in relation to models of the high-temperature layers, are presented. A Black Brant rocket was used to obtain 1-arc sec resolution L-alpha pictures of the sun, which revealed small scale features not seen previously at this wavelength, that delineate the geometry of the magnetic field in the chromosphere and in the corona. It is concluded that these observations might provide a new way of observing the upper chromosphere and corona, and that they provide direct evidence of the inhomogeneous character of the chromosphere and of the dominant role of the magnetic field

  8. Discovery of a very Lyman-α-luminous quasar at z = 6.62.

    Science.gov (United States)

    Koptelova, Ekaterina; Hwang, Chorng-Yuan; Yu, Po-Chieh; Chen, Wen-Ping; Guo, Jhen-Kuei

    2017-02-02

    Distant luminous quasars provide important information on the growth of the first supermassive black holes, their host galaxies and the epoch of reionization. The identification of quasars is usually performed through detection of their Lyman-α line redshifted to 0.9 microns at z > 6.5. Here, we report the discovery of a very Lyman-α luminous quasar, PSO J006.1240 + 39.2219 at redshift z = 6.618, selected based on its red colour and multi-epoch detection of the Lyman-α emission in a single near-infrared band. The Lyman-α line luminosity of PSO J006.1240 + 39.2219 is unusually high and estimated to be 0.8 × 10 12 Solar luminosities (about 3% of the total quasar luminosity). The Lyman-α emission of PSO J006.1240 + 39.2219 shows fast variability on timescales of days in the quasar rest frame, which has never been detected in any of the known high-redshift quasars. The high luminosity of the Lyman-α line, its narrow width and fast variability resemble properties of local Narrow-Line Seyfert 1 galaxies which suggests that the quasar is likely at the active phase of the black hole growth accreting close or even beyond the Eddington limit.

  9. Lyman-continuum leakage as dominant source of diffuse ionized gas in the Antennae galaxy

    Science.gov (United States)

    Weilbacher, Peter M.; Monreal-Ibero, Ana; Verhamme, Anne; Sandin, Christer; Steinmetz, Matthias; Kollatschny, Wolfram; Krajnović, Davor; Kamann, Sebastian; Roth, Martin M.; Erroz-Ferrer, Santiago; Marino, Raffaella Anna; Maseda, Michael V.; Wendt, Martin; Bacon, Roland; Dreizler, Stefan; Richard, Johan; Wisotzki, Lutz

    2018-04-01

    The Antennae galaxy (NGC 4038/39) is the closest major interacting galaxy system and is therefore often studied as a merger prototype. We present the first comprehensive integral field spectroscopic dataset of this system, observed with the MUSE instrument at the ESO VLT. We cover the two regions in this system which exhibit recent star formation: the central galaxy interaction and a region near the tip of the southern tidal tail. In these fields, we detect HII regions and diffuse ionized gas to unprecedented depth. About 15% of the ionized gas was undetected by previous observing campaigns. This newly detected faint ionized gas is visible everywhere around the central merger, and shows filamentary structure. We estimate diffuse gas fractions of about 60% in the central field and 10% in the southern region. We are able to show that the southern region contains a significantly different population of HII regions, showing fainter luminosities. By comparing HII region luminosities with the HST catalog of young star clusters in the central field, we estimate that there is enough Lyman-continuum leakage in the merger to explain the amount of diffuse ionized gas that we detect. We compare the Lyman-continuum escape fraction of each HII region against emission line ratios that are sensitive to the ionization parameter. While we find no systematic trend between these properties, the most extreme line ratios seem to be strong indicators of density bounded ionization. Extrapolating the Lyman-continuum escape fractions to the southern region, we conclude that simply from the comparison of the young stellar populations to the ionized gas there is no need to invoke other ionization mechanisms than Lyman-continuum leaking HII regions for the diffuse ionized gas in the Antennae. FITS images and Table of HII regions are available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/611/A95 and at http://muse-vlt.eu/science/antennae/

  10. A reliable cw Lyman-α laser source for future cooling of antihydrogen

    International Nuclear Information System (INIS)

    Kolbe, Daniel; Beczkowiak, Anna; Diehl, Thomas; Koglbauer, Andreas; Sattler, Matthias; Stappel, Matthias; Steinborn, Ruth; Walz, Jochen

    2012-01-01

    We demonstrate a reliable continuous-wave (cw) laser source at the 1 S–2 P transition in (anti)hydrogen at 121.56 nm (Lyman-α) based on four-wave sum-frequency mixing in mercury. A two-photon resonance in the four-wave mixing scheme is essential for a powerful cw Lyman-α source and is well investigated.

  11. Witnessing the assembly of galaxies in an extended gas-rich structure at z 3.25

    Science.gov (United States)

    Mackenzie, Ruari

    2017-08-01

    The direct study of star formation in Damped Lyman Alpha systems (DLAs), the reservoirs of the majority of neutral gas at high redshift, has previously been hampered by the lack of deep integral field spectroscopy for sensitive searches of faint host galaxies. Building on our successful HST shot-in-the-dark survey that has probed the in-situ star formation rate of z 2-3 DLAs, we have initiated a MUSE follow-up of 6 DLA signlines to overcome this bottleneck. In the first sightline we have studied, we have uncovered a 40 kpc Lyman alpha emitting nebula, composed of two clumps within 50 kpc of the DLA, suggestive of a merger or an extended protodisk. Within this structure, which is the largest nebula known to be associated with a z 3 DLA, we also found a compact continuum source with spectrophotometry consistent with a Lyman Break Galaxy at the same redshift. Aside from the LBG, the rest of the Lyman alpha structure has no continuum counterpart in deep UV and visible imaging. The LBG alone seems unable to power the Lyman alpha nebula and the morphology supports our conclusion that, most likely, this structure is powered by in-situ star formation below detection limit. However, from the Lyman alpha alone the origin of this incredible structure remains ambiguous. With this proposal, we aim to acquire high resolution, deep infrared imaging with HST to probe the rest-frame optical emission to search for the underlying stellar emission of this object and to infer the stellar mass of the LBG. With the powerful combination of HST and MUSE data, we will unravel the nature of this unique system.

  12. First Results from the Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) Survey: Cosmological Reionization at z ∼ 7

    Energy Technology Data Exchange (ETDEWEB)

    Zheng, Zhen-Ya; Jiang, Chunyan [CAS Key Laboratory for Research in Galaxies and Cosmology, Shanghai Astronomical Observatory, Shanghai 200030 (China); Wang, Junxian; Hu, Weida; Kong, Xu [CAS Key Laboratory for Research in Galaxies and Cosmology, Department of Astronomy, University of Science and Technology of China, Hefei, Anhui 230026 (China); Rhoads, James; Malhotra, Sangeeta; Gonzalez, Alicia [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Infante, Leopoldo; Galaz, Gaspar; Barrientos, L. Felipe [Institute of Astrophysics and Center for Astroengineering, Pontificia Universidad Catolica de Chile, Santiago 7820436 (Chile); Walker, Alistair R. [Cerro Tololo Inter-American Observatory, Casilla 603, La Serena (Chile); Jiang, Linhua [The Kavli Institute for Astronomy and Astrophysics, Peking University, Beijing 100871 (China); Hibon, Pascale [European Southern Observatory, Alonso de Cordova 3107, Casilla 19001, Santiago (Chile); Zheng, XianZhong, E-mail: zhengzy@shao.ac.cn, E-mail: linfante@astro.puc.cl, E-mail: jxw@ustc.edu.cn, E-mail: Sangeeta.Malhotra@asu.edu, E-mail: James.Rhoads@asu.edu [Purple Mountain Observatory, Chinese Academy of Sciences, Nanjing 210008 (China)

    2017-06-20

    We present the first results from the ongoing Lyman Alpha Galaxies in the Epoch of Reionization (LAGER) project, which is the largest narrowband survey for z ∼ 7 galaxies to date. Using a specially built narrowband filter NB964 for the superb large-area Dark Energy Camera (DECam) on the NOAO/CTIO 4 m Blanco telescope, LAGER has collected 34 hr NB964 narrowband imaging data in the 3 deg{sup 2} COSMOS field. We have identified 23 Ly α Emitter candidates at z = 6.9 in the central 2-deg{sup 2} region, where DECam and public COSMOS multi-band images exist. The resulting luminosity function (LF) can be described as a Schechter function modified by a significant excess at the bright end (four galaxies with L {sub Lyα∼} 10{sup 43.4±0.2} erg s{sup −1}). The number density at L {sub Ly} {sub α} ∼ 10{sup 43.4±0.2} erg s{sup −1} is little changed from z = 6.6, while at fainter L {sub Lyα} it is substantially reduced. Overall, we see a fourfold reduction in Ly α luminosity density from z = 5.7 to z = 6.9. Combined with a more modest evolution of the continuum UV luminosity density, this suggests a factor of ∼3 suppression of Ly α by radiative transfer through the z ∼ 7 intergalactic medium (IGM). It indicates an IGM neutral fraction of x {sub Hi} ∼ 0.4–0.6 (assuming Ly α velocity offsets of 100–200 km s{sup −1}). The changing shape of the Ly α LF between z ≲ 6.6 and z = 6.9 supports the hypothesis of ionized bubbles in a patchy reionization at z ∼ 7.

  13. Anomalous Temporal Behaviour of Broadband Ly Alpha Observations During Solar Flares from SDO/EVE

    Science.gov (United States)

    Milligan, Ryan O.; Chamberlin, Phillip C.

    2016-01-01

    Although it is the most prominent emission line in the solar spectrum, there has been a notable lack of studies devoted to variations in Lyman-alpha (Ly-alpha) emission during solar flares in recent years. However, the few examples that do exist have shown Ly-alpha emission to be a substantial radiator of the total energy budget of solar flares (of the order of 10 percent). It is also a known driver of fluctuations in the Earth's ionosphere. The EUV (Extreme Ultra-Violet) Variability Experiment (EVE) on board the Solar Dynamics Observatory (SDO) now provides broadband, photometric Ly-alpha data at 10-second cadence with its Multiple EUV Grating Spectrograph-Photometer (MEGS-P) component, and has observed scores of solar flares in the 5 years since it was launched. However, the MEGS-P time profiles appear to display a rise time of tens of minutes around the time of the flare onset. This is in stark contrast to the rapid, impulsive increase observed in other intrinsically chromospheric features (H-alpha, Ly-beta, LyC, C III, etc.). Furthermore, the emission detected by MEGS-P peaks around the time of the peak of thermal soft X-ray emission and not during the impulsive phase when energy deposition in the chromosphere (often assumed to be in the form of non-thermal electrons) is greatest. The time derivative of Ly-alpha lightcurves also appears to resemble that of the time derivative of soft X-rays, reminiscent of the Neupert effect. Given that spectrally-resolved Ly-alpha observations during flares from SORCE / SOLSTICE (Solar Radiation and Climate Experiment / Solar Stellar Irradiance Comparison Experiment) peak during the impulsive phase as expected, this suggests that the atypical behaviour of MEGS-P data is a manifestation of the broadband nature of the observations. This could imply that other lines andor continuum emission that becomes enhanced during flares could be contributing to the passband. Users are hereby urged to exercise caution when interpreting

  14. Low redshift Lyman alpha absorption lines and the dark matter halos of disk galaxies

    Science.gov (United States)

    Maloney, Philip

    1993-01-01

    Recent observations using the Hubble Space Telescope of the z = 0.156 QSO 3C 273 have discovered a surprisingly large number of Ly-alpha absorption lines. In particular, Morris et al. found 9 certain and 7 possible Ly-alpha lines with equivalent widths above 25 mA. This is much larger (by a factor of 5-10) than the number expected from extrapolation of the high-redshift behavior of the Ly-alpha forest. Within the context of pressure-confined models for the Ly-alpha clouds, this behavior can be understood if the ionizing background declines sharply between z is approximately 2 and z is approximately 0. However, this requires that the ionizing photon flux drop as rapidly as the QSO volume emissivity; moreover, the absorbers must have a space density n(sub O) is approximately 2.6(N/10)h/((D/100 kpc)(sup 2)) Mpc(sup -3) where D is the present-day diameter of the absorbers. It is somewhat surprising that such necessarily fragile objects could have survived in such numbers to the present day. It is shown that it is plausible that the atomic hydrogen extents of spiral and irregular galaxies are large enough to produce the observed number of Ly-alpha absorption lines toward 3C 273, and that the neutral column densities and doppler b-values expected under these conditions fall in the range found by Morris et al. (1991).

  15. VOYAGER 1&2 JUPITER BRIGHTNESS NORTH/SOUTH MAP SET V1.0

    Data.gov (United States)

    National Aeronautics and Space Administration — This data set contains Voyager 1 and 2 measurements of the brightness of Jupiter at H Lyman alpha and in the H2 Lyman and Werner bands shortward of H Lyman alpha....

  16. Lyman Break Galaxies in the Hubble Ultra Deep Field through Deep U-Band Imaging

    Science.gov (United States)

    Rafelski, Marc; Wolfe, A. M.; Cooke, J.; Chen, H. W.; Armandroff, T. E.; Wirth, G. D.

    2009-12-01

    We introduce an extremely deep U-band image taken of the Hubble Ultra Deep Field (HUDF), with a one sigma depth of 30.7 mag arcsec-2 and a detection limiting magnitude of 28 mag arcsec-2. The observations were carried out on the Keck I telescope using the LRIS-B detector. The U-band image substantially improves the accuracy of photometric redshift measurements of faint galaxies in the HUDF at z=[2.5,3.5]. The U-band for these galaxies is attenuated by lyman limit absorption, allowing for more reliable selections of candidate Lyman Break Galaxies (LBGs) than from photometric redshifts without U-band. We present a reliable sample of 300 LBGs at z=[2.5,3.5] in the HUDF. Accurate redshifts of faint galaxies at z=[2.5,3.5] are needed to obtain empirical constraints on the star formation efficiency of neutral gas at high redshift. Wolfe & Chen (2006) showed that the star formation rate (SFR) density in damped Ly-alpha absorption systems (DLAs) at z=[2.5,3.5] is significantly lower than predicted by the Kennicutt-Schmidt law for nearby galaxies. One caveat to this result that we wish to test is whether LBGs are embedded in DLAs. If in-situ star formation is occurring in DLAs, we would see it as extended low surface brightness emission around LBGs. We shall use the more accurate photometric redshifts to create a sample of LBGs around which we will look for extended emission in the more sensitive and higher resolution HUDF images. The absence of extended emission would put limits on the SFR density of DLAs associated with LBGs at high redshift. On the other hand, detection of faint emission on scales large compared to the bright LBG cores would indicate the presence of in situ star formation in those DLAs. Such gas would presumably fuel the higher star formation rates present in the LBG cores.

  17. Minihalo Model for the Low-Redshift Lyman alpha Absorbers Revisited

    Directory of Open Access Journals (Sweden)

    Lalović, A.

    2008-06-01

    Full Text Available We reconsider the basic properties of the classical minihalo model of Rees and Milgrom in light of the new work, both observational (on "dark galaxies" and masses of baryonic haloes and theoretical (on the cosmological mass function and the history of star formation. In particular, we show that more detailed models of ionized gas in haloes of dark matter following isothermal and Navarro-Frenk-White density profile can effectively reproduce particular aspects of the observed column density distribution function in a heterogeneous sample of low-and intermediate-redshift Ly$alpha$ forest absorption lines.

  18. arXiv Neutrino masses and cosmology with Lyman-alpha forest power spectrum

    CERN Document Server

    Palanque-Delabrouille, Nathalie; Baur, Julien; Magneville, Christophe; Rossi, Graziano; Lesgourgues, Julien; Borde, Arnaud; Burtin, Etienne; LeGoff, Jean-Marc; Rich, James; Viel, Matteo; Weinberg, David

    2015-11-06

    We present constraints on neutrino masses, the primordial fluctuation spectrum from inflation, and other parameters of the $\\Lambda$CDM model, using the one-dimensional Ly$\\alpha$-forest power spectrum measured by Palanque-Delabrouille et al. (2013) from SDSS-III/BOSS, complemented by Planck 2015 cosmic microwave background (CMB) data and other cosmological probes. This paper improves on the previous analysis by Palanque-Delabrouille et al. (2015) by using a more powerful set of calibrating hydrodynamical simulations that reduces uncertainties associated with resolution and box size, by adopting a more flexible set of nuisance parameters for describing the evolution of the intergalactic medium, by including additional freedom to account for systematic uncertainties, and by using Planck 2015 constraints in place of Planck 2013. Fitting Ly$\\alpha$ data alone leads to cosmological parameters in excellent agreement with the values derived independently from CMB data, except for a weak tension on the scalar index ...

  19. Dynamical chaos in a linear 3. alpha. system. Dinamicheskij khaos v linejnoj 3. alpha. -sisteme

    Energy Technology Data Exchange (ETDEWEB)

    Bolotin, Yu L; Gonchar, V Yu; Chekanov, N A [AN Ukrainskoj SSR, Kharkov (Ukrainian SSR). Fiziko-Tekhnicheskij Inst.; Vinitskij, S I [Joint Inst. for Nuclear Research, Dubna (USSR)

    1989-01-01

    Classical dynamics of the motion of a molecular model of the carbon nucleus, which is a linear 3{alpha} system with realistic {alpha}{alpha} interaction is studied. Transition from a regular to a chaos motion in the nuclear molecule is shown to occur with growing energy more rapidly than in model problems with polynomial potentials. It is found that in a small region of the phase space the motion remains regular at energies higher than the 3{alpha}-system dissociation threshold. This is probably related to the C{sub 3v}-symmetry violation. Formulas for the quasiclassical spectrum of the 3{alpha} system are obtained with the use of the Birkhoff normal form.

  20. Fluorescence Lyman-Alpha Stratospheric Hygrometer (FLASH): application on meteorological balloons, long duration balloons and unmanned aerial vehicles.

    Science.gov (United States)

    Lykov, Alexey; Khaykin, Sergey; Yushkov, Vladimir; Efremov, Denis; Formanyuk, Ivan; Astakhov, Valeriy

    The FLASH instrument is based on the fluorescent method, which uses H2O molecules photodissociation at a wavelength lambda=121.6 nm (Lalpha - hydrogen emission) followed by the measurement of the fluorescence of excited OH radicals. The source of Lyman-alpha radiation is a hydrogen discharge lamp while the detector of OH fluorescence at 308 -316 nm is a photomultiplier run in photon counting mode. The intensity of the fluorescent light as well as the instrument readings is directly proportional to the water vapor mixing ratio under stratospheric conditions with negligible oxygen absorption. Initially designed for rocket-borne application, FLASH has evolved into a light-weight balloon sonde (FLASH-B) for measurements in the upper troposphere and stratosphere on board meteorological and small plastic balloons. This configuration has been used in over 100 soundings at numerous tropical mid-latitude and polar locations within various international field campaigns. An airborne version of FLASH instrument is successfully utilized onboard stratospheric M55-Geophysica aircraft and tropospheric airborne laboratory YAK42-Roshydromet. The hygrometer was modified for application onboard stratospheric long-duration balloons (FLASH-LDB version). This version was successfully used onboard CNES super-pressure balloon launched from SSC Esrange in March 2007 and flown during 10 days. Special design for polar long duration balloon PoGOLite was created for testing work during polar day in June 2013. Installation and measurement peculiarities as well as observational results are presented. Observations of water vapour using FLASH-B instrument, being of high quality are rather costly as the payload recovery is often complicated and most of the time impossible. Following the goal to find a cost-efficient solution, FLASH was adapted for use onboard Unmanned Aerial Vehicles (UAV). This solution was only possible thanks to compactness and light-weight (0.5 kg) of FLASH instrument. The

  1. Ly-alpha polarimeter design for CLASP rocket experiment

    Science.gov (United States)

    Kubo, M.; Watanabe, H.; Narukage, N.; Ishikawa, R.; Bando, T.; Kano, R.; Tsuneta, S.; Kobayashi, K.; Ichimoto, K.; Trujillo Bueno, J.; Song, D.

    2011-12-01

    A sounding-rocket program called the Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is proposed to be launched in the Summer of 2014. CLASP will observe the upper solar chromosphere in Ly-alpha (121.567 nm), aiming to detect the linear polarization signal produced by scattering processes and the Hanle effect for the first time. The CLASP needs a rotating half-waveplate and a polarization analyzer working at the Ly-alpha wavelength to measure the linear polarization signal. We select Magnesium Fluoride (MgF2) as a material of the optical components because of its birefringent property and high transparency at UV wavelength. We have confirmed that the reflection at the Brewster's Angle of MgF2 plate is a good polarization analyzer for the Ly-alpha line by deriving its ordinary refractive index and extinction coefficient along the ordinary and extraordinary axes. These optical parameters are calculated with a least-square fitting in such a way that the reflectance and transmittance satisfy the Kramers-Kronig relation. The reflectance and transmittance against oblique incident angles for the s-polarized and the p-polarized light are measured using the synchrotron beamline at the Ultraviolet Synchrotron Orbital Radiation Facility (UVSOR). We have also measured a retardation of a zeroth-order waveplate made of MgF2. The thickness difference of the waveplate is 14.57 um.This waveplate works as a half-waveplate at 121.74 nm. From this measurement, we estimate that a waveplate with the thickness difference of 15.71 um will work as a half-waveplate at the Ly-alpha wavelength. We have developed a rotating waveplate - polarization analyzer system called a prototype of CLASP polarimeter, and input the perfect Stokes Q and U signals. The modulation patterns that are consistent with the theoretical prediction are successfully obtained in both cases.

  2. Technical Equivalency Documentation for a Newly Acquired Alpha Spectroscopy System

    International Nuclear Information System (INIS)

    Hickman, D P; Fisher, S K; Hann, P R; Hume, R

    2007-01-01

    The response of a recently acquired Canberra(trademark) Alpha Analyst 'Blue' system (Chamber Number's 173-208) used by the Hazards Control, Radiation Safety Section, WBC/Spectroscopy Team has been studied with respect to an existing Canberra system. The existing Canberra system consists of thirty Alpha Analyst dual chambers Model XXXX comprising a total of sixty detectors (Chambers Number's 101-124 and 137-172). The existing chambers were previously compared to an older system consisting of thirty-six Model 7401 alpha spectrometry chambers (Chamber Number's 1-36) Chambers 101-124 and 137-172 are DOELAP accredited. The older system was previously DOELAP accredited for the routine Alpha Spectroscopy program used in LLNL's in vitro bioassay program. The newly acquired Alpha Analyst system operates on a network with software that controls and performs analysis of the current Alpha Analyst system (Chamber Number's 101-124 and 137-172). This exact same software is used for the current system and the newly acquired system and is DOELAP accredited. This document compares results from the existing Alpha System with the newer Alpha Analyst system

  3. Increased virulence and competitive advantage of a/alpha over a/a or alpha/alpha offspring conserves the mating system of Candida albicans.

    Science.gov (United States)

    Lockhart, Shawn R; Wu, Wei; Radke, Joshua B; Zhao, Rui; Soll, David R

    2005-04-01

    The majority of Candida albicans strains in nature are a/alpha and must undergo homozygosis to a/a or alpha/alpha to mate. Here we have used a mouse model for systemic infection to test the hypothesis that a/alpha strains predominate in nature because they have a competitive advantage over a/a and alpha/alpha offspring in colonizing hosts. Single-strain injection experiments revealed that a/alpha strains were far more virulent than either their a/a or alpha/alpha offspring. When equal numbers of parent a/alpha and offspring a/a or alpha/alpha cells were co-injected, a/alpha always exhibited a competitive advantage at the time of extreme host morbidity or death. When equal numbers of an engineered a/a/alpha2 strain and its isogenic a/a parent strain were co-injected, the a/a/alpha2 strain exhibited a competitive advantage at the time of host morbidity or death, suggesting that the genotype of the mating-type (MTL) locus, not associated genes on chromosome 5, provides a competitive advantage. We therefore propose that heterozygosity at the MTL locus not only represses white-opaque switching and genes involved in the mating process, but also affects virulence, providing a competitive advantage to the a/alpha genotype that conserves the mating system of C. albicans in nature.

  4. Set-up of an alpha-spectrometry system

    International Nuclear Information System (INIS)

    Calicchia, A.

    1976-01-01

    Principle of operation of alpha-spectrometry system is described, using a solid state detector, which allows to precisely determine sample's activity and specify alpha-emitting radionuclides. Measurements which allow to define system performances are shown, that is energy resolution and real sensitivity of spectrometer

  5. Fragmentation inside atomic cooling haloes exposed to Lyman-Werner radiation

    Science.gov (United States)

    Regan, John A.; Downes, Turlough P.

    2018-04-01

    Supermassive stars born in pristine environments in the early Universe hold the promise of being the seeds for the supermassive black holes observed as high redshift quasars shortly after the epoch of reionisation. H2 suppression is thought to be crucial in order to negate normal Population III star formation and allow high accretion rates to drive the formation of supermassive stars. Only in the cases where vigorous fragmentation is avoided will a monolithic collapse be successful, giving rise to a single massive central object. We investigate the number of fragmentation sites formed in collapsing atomic cooling haloes subject to various levels of background Lyman-Werner flux. The background Lyman-Werner flux manipulates the chemical properties of the gas in the collapsing halo by destroying H2. We find that only when the collapsing gas cloud shifts from the molecular to the atomic cooling regime is the degree of fragmentation suppressed. In our particular case, we find that this occurs above a critical Lyman-Werner background of J ˜ 10 J21. The important criterion being the transition to the atomic cooling regime rather than the actual value of J, which will vary locally. Once the temperature of the gas exceeds T ≳ 104 K and the gas transitions to atomic line cooling, then vigorous fragmentation is strongly suppressed.

  6. Small-scale structure and the Lyman-α forest baryon acoustic oscillation feature

    Science.gov (United States)

    Hirata, Christopher M.

    2018-02-01

    The baryon-acoustic oscillation (BAO) feature in the Lyman-α forest is a key probe of the cosmic expansion rate at redshifts z ˜ 2.5, well before dark energy is believed to have become significant. A key advantage of the BAO as a standard ruler is that it is a sharp feature and hence is more robust against broad-band systematic effects than other cosmological probes. However, if the Lyman-α forest transmission is sensitive to the initial streaming velocity of the baryons relative to the dark matter, then the BAO peak position can be shifted. Here we investigate this sensitivity using a suite of hydrodynamic simulations of small regions of the intergalactic medium with a range of box sizes and physics assumptions; each simulation starts from initial conditions at the kinematic decoupling era (z ˜ 1059), undergoes a discrete change from neutral gas to ionized gas thermal evolution at reionization (z ˜ 8), and is finally processed into a Lyman-α forest transmitted flux cube. Streaming velocities suppress small-scale structure, leading to less violent relaxation after reionization. The changes in the gas distribution and temperature-density relation at low redshift are more subtle, due to the convergent temperature evolution in the ionized phase. The change in the BAO scale is estimated to be of the order of 0.12 per cent at z = 2.5; some of the major uncertainties and avenues for future improvement are discussed. The predicted streaming velocity shift would be a subdominant but not negligible effect (of order 0.26σ) for the upcoming DESI Lyman-α forest survey, and exceeds the cosmic variance floor.

  7. Investigating the physics and environment of Lyman limit systems in cosmological simulations

    Science.gov (United States)

    Erkal, Denis

    2015-07-01

    In this work, I investigate the properties of Lyman limit systems (LLSs) using state-of-the-art zoom-in cosmological galaxy formation simulations with on the fly radiative transfer, which includes both the cosmic UV background (UVB) and local stellar sources. I compare the simulation results to observations of the incidence frequency of LLSs and the H I column density distribution function over the redshift range z = 2-5 and find good agreement. I explore the connection between LLSs and their host haloes and find that LLSs reside in haloes with a wide range of halo masses with a nearly constant covering fraction within a virial radius. Over the range z = 2-5, I find that more than half of the LLSs reside in haloes with M test a simple model which encapsulates many of their properties. I confirm that LLSs have a characteristic absorption length given by the Jeans length and that they are in photoionization equilibrium at low column densities. Finally, I investigate the self-shielding of LLSs to the UVB and explore how the non-sphericity of LLSs affects the photoionization rate at a given N_{H I}. I find that at z ≈ 3, LLSs have an optical depth of unity at a column density of ˜1018 cm-2 and that this is the column density which characterizes the onset of self-shielding.

  8. Low-redshift Lyman limit systems as diagnostics of cosmological inflows and outflows

    Science.gov (United States)

    Hafen, Zachary; Faucher-Giguère, Claude-André; Anglés-Alcázar, Daniel; Kereš, Dušan; Feldmann, Robert; Chan, T. K.; Quataert, Eliot; Murray, Norman; Hopkins, Philip F.

    2017-08-01

    We use cosmological hydrodynamic simulations with stellar feedback from the FIRE (Feedback In Realistic Environments) project to study the physical nature of Lyman limit systems (LLSs) at z ≤ 1. At these low redshifts, LLSs are closely associated with dense gas structures surrounding galaxies, such as galactic winds, dwarf satellites and cool inflows from the intergalactic medium. Our analysis is based on 14 zoom-in simulations covering the halo mass range Mh ≈ 109-1013 M⊙ at z = 0, which we convolve with the dark matter halo mass function to produce cosmological statistics. We find that the majority of cosmologically selected LLSs are associated with haloes in the mass range 1010 ≲ Mh ≲ 1012 M⊙. The incidence and H I column density distribution of simulated absorbers with columns in the range 10^{16.2} ≤ N_{H I} ≤ 2× 10^{20} cm-2 are consistent with observations. High-velocity outflows (with radial velocity exceeding the halo circular velocity by a factor of ≳ 2) tend to have higher metallicities ([X/H] ˜ -0.5) while very low metallicity ([X/H] standard deviation) [X/H] = -0.9 (0.4) and does not show significant evidence for bimodality, in contrast to recent observational studies, but consistent with LLSs arising from haloes with a broad range of masses and metallicities.

  9. The Lyman-α forest in three dimensions: measurements of large scale flux correlations from BOSS 1st-year data

    Energy Technology Data Exchange (ETDEWEB)

    Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton NY 11375 (United States); Font-Ribera, Andreu [Institut de Ciències de l' Espai (CSIC-IEEC), Campus UAB, Fac. Ciències, torre C5 parell 2, Bellaterra, Catalonia (Spain); Pieri, Matthew M. [Center for Astrophysics and Space Astronomy, University of Colorado, 389 UCB, Boulder, Colorado 80309 (United States); Rich, James; Goff, Jean-Marc Le; Charlassier, Romain [CEA, Centre de Saclay, IRFU, 91191 Gif-sur-Yvette (France); Aubourg, Éric; Busca, Nicolas; Hamilton, Jean-Christophe [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Brinkmann, Jon [Apache Point Observatory, P.O. Box 59, Sunspot, NM 88349 (United States); Carithers, Bill; Cortês, Marina; Ho, Shirley; McDonald, Patrick [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Croft, Rupert [Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Dawson, Kyle S. [University of Utah, Dept. of Physics and Astronomy, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Eisenstein, Daniel [Harvard College Observatory, 60 Garden St., Cambridge MA 02138 (United States); Lee, Khee-Gan; Lupton, Robert [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States); Medolin, Bumbarija, E-mail: anze@bnl.gov [104-20 Queens Blvd 17A, Forest Hills, NY 11375 (United States); and others

    2011-09-01

    Using a sample of approximately 14,000 z > 2.1 quasars observed in the first year of the Baryon Oscillation Spectroscopic Survey (BOSS), we measure the three-dimensional correlation function of absorption in the Lyman-α forest. The angle-averaged correlation function of transmitted flux (F = e{sup −τ}) is securely detected out to comoving separations of 60 h{sup −1}Mpc, the first detection of flux correlations across widely separated sightlines. A quadrupole distortion of the redshift-space correlation function by peculiar velocities, the signature of the gravitational instability origin of structure in the Lyman-α forest, is also detected at high significance. We obtain a good fit to the data assuming linear theory redshift-space distortion and linear bias of the transmitted flux, relative to the matter fluctuations of a standard ΛCDM cosmological model (inflationary cold dark matter with a cosmological constant). At 95% confidence, we find a linear bias parameter 0.16 < b < 0.24 and redshift-distortion parameter 0.44 < β < 1.20, at central redshift z = 2.25, with a well constrained combination b(1+β) = 0.336±0.012. The errors on β are asymmetric, with β = 0 excluded at over 5σ confidence level. The value of β is somewhat low compared to theoretical predictions, and our tests on synthetic data suggest that it is depressed (relative to expectations for the Lyman-α forest alone) by the presence of high column density systems and metal line absorption. These results set the stage for cosmological parameter determinations from three-dimensional structure in the Lyman-α forest, including anticipated constraints on dark energy from baryon acoustic oscillations.

  10. alpha-MSH in systemic inflammation. Central and peripheral actions.

    Science.gov (United States)

    Catania, A; Delgado, R; Airaghi, L; Cutuli, M; Garofalo, L; Carlin, A; Demitri, M T; Lipton, J M

    1999-10-20

    Until recently, inflammation was believed to arise from events taking place exclusively in the periphery. However, it is now clear that central neurogenic influences can either enhance or modulate peripheral inflammation. Therefore, it should be possible to improve treatment of inflammation by use of antiinflammatory agents that reduce peripheral host responses and inhibit proinflammatory signals in the central nervous system (CNS). One such strategy could be based on alpha-melanocyte stimulating hormone (alpha-MSH). Increases in circulating TNF-alpha and nitric oxide (NO), induced by intraperitoneal administration of endotoxin in mice, were modulated by central injection of a small concentration of alpha-MSH. Inducible nitric oxide synthase (iNOS) activity and iNOS mRNA in lungs and liver were likewise modulated by central alpha-MSH. Increase in lung myeloperoxidase (MPO) activity was significantly less in lungs of mice treated with central alpha-MSH. Proinflammatory agents induced by endotoxin were significantly greater after blockade of central alpha-MSH. The results suggest that antiinflammatory influences of neural origin that are triggered by alpha-MSH could be used to treat systemic inflammation. In addition to its central influences, alpha-MSH has inhibitory effects on peripheral host cells, in which it reduces release of proinflammatory mediators. alpha-MSH reduces chemotaxis of human neutrophils and production of TNF-alpha, neopterin, and NO by monocytes. In research on septic patients, alpha-MSH inhibited release of TNF-alpha, interleukin-1 beta (IL-1 beta), and interleukin-8 (IL-8) in whole blood samples in vitro. Combined central and peripheral influences can be beneficial in treatment of sepsis.

  11. Twenty years of research on fungal-plant interactions on Lyman Glacier forefront—lessons learned and questions yet unanswered

    Science.gov (United States)

    Ari Jumpponen; Shawn P. Brown; James M. Trappe; Efrén Cázares; Rauni. Strömmer

    2012-01-01

    Retreating glaciers and the periglacial areas that they vacate produce a harsh environment of extreme radiation, nutrient limitations and temperature oscillations. They provide a model system for studying mechanisms that drive the establishment and early assembly of communities. Here, we synthesize more than 20 years of research at the Lyman Glacier forefront in the...

  12. Late Rectal Toxicity on RTOG 94-06: Analysis Using a Mixture Lyman Model

    International Nuclear Information System (INIS)

    Tucker, Susan L.; Dong Lei; Bosch, Walter R.; Michalski, Jeff; Winter, Kathryn; Mohan, Radhe; Purdy, James A.; Kuban, Deborah; Lee, Andrew K.; Cheung, M. Rex; Thames, Howard D.; Cox, James D.

    2010-01-01

    Purpose: To estimate the parameters of the Lyman normal-tissue complication probability model using censored time-to-event data for Grade ≥2 late rectal toxicity among patients treated on Radiation Therapy Oncology Group 94-06, a dose-escalation trial designed to determine the maximum tolerated dose for three-dimensional conformal radiotherapy of prostate cancer. Methods and Materials: The Lyman normal-tissue complication probability model was fitted to data from 1,010 of the 1,084 patients accrued on Radiation Therapy Oncology Group 94-06 using an approach that accounts for censored observations. Separate fits were obtained using dose-volume histograms for whole rectum and dose-wall histograms for rectal wall. Results: With a median follow-up of 7.2 years, the crude incidence of Grade ≥2 late rectal toxicity was 15% (n = 148). The parameters of the Lyman model fitted to dose-volume histograms data, with 95% profile-likelihood confidence intervals, were TD 50 = 79.1 Gy (75.3 Gy, 84.3 Gy), m = 0.146 (0.107, 0.225), and n = 0.077 (0.041, 0.156). The fit based on dose-wall histogram data was not significantly different. Patients with cardiovascular disease had a significantly higher incidence of late rectal toxicity (p = 0.015), corresponding to a dose-modifying factor of 5.3%. No significant association with late rectal toxicity was found for diabetes, hypertension, rectal volume, rectal length, neoadjuvant hormone therapy, or prescribed dose per fraction (1.8 Gy vs. 2 Gy). Conclusions: These results, based on a large cohort of patients from a multi-institutional trial, are expected to be widely representative of the ability of the Lyman model to describe the long-term risk of Grade ≥2 late rectal toxicity after three-dimensional conformal radiotherapy of prostate cancer.

  13. GAS MOTION STUDY OF Ly{alpha} EMITTERS AT z {approx} 2 USING FUV AND OPTICAL SPECTRAL LINES {sup ,}

    Energy Technology Data Exchange (ETDEWEB)

    Hashimoto, Takuya; Shimasaku, Kazuhiro; Nakajima, Kimihiko [Department of Astronomy, Graduate School of Science, The University of Tokyo, Tokyo 113-0033 (Japan); Ouchi, Masami; Ono, Yoshiaki [Institute for Cosmic Ray Research, The University of Tokyo, 5-1-5 Kashiwanoha, Kashiwa, Chiba 277-8582 (Japan); Rauch, Michael; Janice Lee [Observatories of the Carnegie Institution of Washington, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Okamura, Sadanori, E-mail: thashimoto@astron.s.u-tokyo.ac.jp [Department of Advanced Sciences, Faculty of Science and Engineering, Hosei University, 3-7-2 Kajino-cho, Koganei-shi, Tokyo 184-8584 (Japan)

    2013-03-01

    We present the results of Magellan/MMIRS and Keck/NIRSPEC spectroscopy for five Ly{alpha} emitters (LAEs) at z {approx_equal} 2.2 for which high-resolution FUV spectra from Magellan/MagE are available. We detect nebular emission lines including H{alpha} on the individual basis and low-ionization interstellar (LIS) absorption lines in a stacked FUV spectrum, and measure average offset velocities of the Ly{alpha} line, {Delta}v {sub Ly{alpha}}, and LIS absorption lines, {Delta}v {sub abs}, with respect to the systemic velocity defined by the nebular lines. For a sample of eight z {approx} 2-3 LAEs without active galactic nucleus from our study and the literature, we obtain {Delta}v {sub Ly{alpha}} = 175 {+-} 35 km s{sup -1}, which is significantly smaller than that of Lyman-break Galaxies (LBGs), {Delta}v {sub Ly{alpha}} {approx_equal} 400 km s{sup -1}. The stacked FUV spectrum gives {Delta}v {sub abs} = -179 {+-} 73 km s{sup -1}, comparable to that of LBGs. These positive {Delta}v {sub Ly{alpha}} and negative {Delta}v {sub abs} suggest that LAEs also have outflows. In contrast to LBGs, however, the LAEs' {Delta}v {sub Ly{alpha}} is as small as |{Delta}v {sub abs}|, suggesting low neutral hydrogen column densities. Such a low column density with a small number of resonant scattering may cause the observed strong Ly{alpha} emission of LAEs. We find an anti-correlation between Ly{alpha} equivalent width (EW) and {Delta}v {sub Ly{alpha}} in a compilation of LAE and LBG samples. Although its physical origin is not clear, this anti-correlation result appears to challenge the hypothesis that a strong outflow, by means of a reduced number of resonant scattering, produces a large EW. If LAEs at z > 6 have similarly small {Delta}v {sub Ly{alpha}} values, constraints on the reionization history derived from the Ly{alpha} transmissivity may need to be revised.

  14. Oasis-an innovative system for alpha spectroscopy

    Energy Technology Data Exchange (ETDEWEB)

    Seymour, R; Richards, W; Knight, K; El-Sayad, G [Oxford Instruments Inc., P.O. Box 2560, Oak Ridge, TN 37831-2560 (United States)

    1995-10-01

    Until recently, instrumental alpha spectroscopy has behind the technical developments of instrumentation and software that are available for low background o c/ counting, liquid scintillation, and gamma spectroscopy instruments. We report in this paper, the development of Oasis, a new family of alpha spectroscopy systems from oxford instruments Inc., Nuclear measurements Group. The Oasis instruments incorporate many hardware and software innovations providing an automated and integrated production environment for alpha spectroscopy. These instruments are needed because of the large number of samples to be measured and the required throughput of production laboratories processing these samples. Oasis is also useful for facilities because of their sophisticated vacuum control, management, and analysis features. One of the most important innovations is the electronic vacuum system and cartesian diver. Many additional features contribute to improving accuracy, lowering cost per sample, improving sample throughput, and ensuring accountability of laboratory results. 5 figs.

  15. Oasis-an innovative system for alpha spectroscopy

    International Nuclear Information System (INIS)

    Seymour, R.; Richards, W.; Knight, K.; El-Sayad, G.

    1995-01-01

    Until recently, instrumental alpha spectroscopy has behind the technical developments of instrumentation and software that are available for low background o c/ counting, liquid scintillation, and gamma spectroscopy instruments. We report in this paper, the development of Oasis, a new family of alpha spectroscopy systems from oxford instruments Inc., Nuclear measurements Group. The Oasis instruments incorporate many hardware and software innovations providing an automated and integrated production environment for alpha spectroscopy. These instruments are needed because of the large number of samples to be measured and the required throughput of production laboratories processing these samples. Oasis is also useful for facilities because of their sophisticated vacuum control, management, and analysis features. One of the most important innovations is the electronic vacuum system and cartesian diver. Many additional features contribute to improving accuracy, lowering cost per sample, improving sample throughput, and ensuring accountability of laboratory results. 5 figs

  16. Alpha low-level stored waste systems design study

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Teheranian, B. (Morrison Knudson Corp., San Francisco, CA (United States). Environmental Services Div.); Quapp, W.J. (EG and G Idaho, Inc., Idaho Falls, ID (United States))

    1992-08-01

    The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex's Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT E) requirements for each of the three concepts.

  17. Alpha low-level stored waste systems design study

    Energy Technology Data Exchange (ETDEWEB)

    Feizollahi, F.; Teheranian, B. [Morrison Knudson Corp., San Francisco, CA (United States). Environmental Services Div.; Quapp, W.J. [EG and G Idaho, Inc., Idaho Falls, ID (United States)

    1992-08-01

    The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex`s Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT&E) requirements for each of the three concepts.

  18. Alpha low-level stored waste systems design study

    International Nuclear Information System (INIS)

    Feizollahi, F.; Teheranian, B.

    1992-08-01

    The Stored Waste System Design Study (SWSDS), commissioned by the Waste Technology Development Department at the Idaho National Engineering Laboratory (INEL), examines relative life-cycle costs associated with three system concepts for processing the alpha low-level waste (alpha-LLW) stored at the Radioactive Waste Management Complex's Transuranic Storage Area at the INEL. The three system concepts are incineration/melting; thermal treatment/solidification; and sort, treat, and repackage. The SWSDS identifies system functional and operational requirements and assesses implementability; effectiveness; cost; and demonstration, testing, and evaluation (DT ampersand E) requirements for each of the three concepts

  19. Spectro-polarimetric observation in UV with CLASP to probe the chromosphere and transition region

    Science.gov (United States)

    Kano, Ryouhei; Ishikawa, Ryohko; Winebarger, Amy R.; Auchère, Frédéric; Trujillo Bueno, Javier; Narukage, Noriyuki; Kobayashi, Ken; Bando, Takamasa; Katsukawa, Yukio; Kubo, Masahito; Ishikawa, Shin-Nosuke; Giono, Gabriel; Hara, Hirohisa; Suematsu, Yoshinori; Shimizu, Toshifumi; Sakao, Taro; Tsuneta, Saku; Ichimoto, Kiyoshi; Goto, Motoshi; Cirtain, Jonathan W.; De Pontieu, Bart; Casini, Roberto; Manso Sainz, Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi, Luca; Carlsson, Mats

    2016-05-01

    The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is a NASA sounding-rocket experiment that was performed in White Sands in the US on September 3, 2015. During its 5-minute ballistic flight, CLASP successfully made the first spectro-polarimetric observation in the Lyman-alpha line (121.57 nm) originating in the chromosphere and transition region. Since the Lyman-alpha polarization is sensitive to magnetic field of 10-100 G by the Hanle effect, we aim to infer the magnetic field information in such upper solar atmosphere with this experiment.The obtained CLASP data showed that the Lyman-alpha scattering polarization is about a few percent in the wings and the order of 0.1% in the core near the solar limb, as it had been theoretically predicted, and that both polarization signals have a conspicuous spatio-temporal variability. CLASP also observed another upper-chromospheric line, Si III (120.65 nm), whose critical field strength for the Hanle effect is 290 G, and showed a measurable scattering polarization of a few % in this line. The polarization properties of the Si III line could facilitate the interpretation of the scattering polarization observed in the Lyman-alpha line.In this presentation, we would like to show how the upper chromosphere and transition region are seen in the polarization of these UV lines and discuss the possible source of these complicated polarization signals.

  20. Alpha Channeling in Open-System Magnetic Devices

    International Nuclear Information System (INIS)

    Fisch, Nathaniel

    2016-01-01

    The Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, is a continuation of the Grant DE-FG02-06ER54851, Alpha Channeling in Mirror Machines. In publications funded by DE-SC0000736, the grant DE-FG02-06ER54851 was actually credited. The key results obtained under Grant DE-SC0000736, Alpha Channeling in Open-System Magnetic Devices, appear in a series of publications. The earlier effort under DE-FG02- 06ER54851 was the subject of a previous Final Report. The theme of this later effort has been unusual confinement effects, or de-confinement effects, in open-field magnetic confinement devices. First, the possibilities in losing axisymmetry were explored. Then a number of issues in rotating plasma were addressed. Most importantly, a spinoff application to plasma separations was recognized, which also resulted in a provisional patent application. (That provisional patent application, however, was not pursued further.) Alpha channeling entails injecting waves into magnetically confined plasma to release energy from one particular ion while ejecting that ion. The ejection of the ion is actually a concomitant effect in releasing energy from the ion to the wave. In rotating plasma, there is the opportunity to store the energy in a radial electric field rather than in waves. In other words, the ejected alpha particle loses its energy to the radial potential, which in turn produces plasma rotation. This is a very useful effect, since producing radial electric fields by other means are technologically more difficult. In fact, one can heat ions, and then eject them, to produce the desired radial field. In each case, there is a separation effect of different ions, which generalizes the original alpha-channeling concept of separating alpha ash from hydrogen. In a further generalization of the separation concept, a double-well filter represents a new way to produce high-throughput separations of ions, potentially useful for nuclear waste remediation.

  1. Resonant line transfer in a fog: using Lyman-alpha to probe tiny structures in atomic gas

    Science.gov (United States)

    Gronke, Max; Dijkstra, Mark; McCourt, Michael; Peng Oh, S.

    2017-11-01

    Motivated by observational and theoretical work that suggest very small-scale (≲ 1 pc) structure in the circumgalactic medium of galaxies and in other environments, we study Lyman-α (Lyα) radiative transfer in an extremely clumpy medium with many clouds of neutral gas along the line of sight. While previous studies have typically considered radiative transfer through sightlines intercepting ≲ 10 clumps, we explored the limit of a very large number of clumps per sightline (up to fc 1000). Our main finding is that, for covering factors greater than some critical threshold, a multiphase medium behaves similarly to a homogeneous medium in terms of the emergent Lyα spectrum. The value of this threshold depends on both the clump column density and the movement of the clumps. We estimated this threshold analytically and compare our findings to radiative transfer simulations with a range of covering factors, clump column densities, radii, and motions. Our results suggest that (I) the success in fitting observed Lyα spectra using homogeneous "shell models" (and the corresponding failure of multiphase models) hints at the presence of very small-scale structure in neutral gas, which is in agreement within a number of other observations; and (II) the recurrent problems of reproducing realistic line profiles from hydrodynamical simulations may be due to their inability to resolve small-scale structure, which causes simulations to underestimate the effective covering factor of neutral gas clouds. The movie associated to Fig. B.2 is available at http://www.aanda.org

  2. Observations of chromospheric lines from OSO-8

    Science.gov (United States)

    Grossmann-Doerth, U.; Kneer, F.; Uexkuell, M.; Artzner, G. E.; Vial, J. C.

    1980-01-01

    Results of OSO-8 measurements of the line profiles of the solar Lyman alpha, Ca II K and Mg II k lines are presented. Observations were obtained with the Laboratoire de Physique Stellaire et Planetaire spectrometer at spectral resolutions of 0.25 and 0.060 A for Lyman alpha and 0.025 A for the Mg II and Ca II lines. The Lyman alpha profiles are found to be highly variable according to spatial position with the intensities of the three lines well correlated, and confirm previous observations of the quiet solar chromosphere. Data suggest that the quiet chromosphere is a dynamical phenomenon whose description in terms of a static model atmosphere is only qualitatively valid at best.

  3. New constraints on Lyman-α opacity using 92 quasar lines of sight

    Science.gov (United States)

    Bosman, Sarah E. I.; Fan, Xiaohui; Jiang, Linhua; Reed, Sophie; Matsuoka, Yoshiki; Becker, George; Rorai, Albert

    2018-05-01

    The large scatter in Lyman-α opacity at z > 5.3 has been an ongoing mystery, prompting a flurry of numerical models. A uniform ultra-violet background has been ruled out at those redshifts, but it is unclear whether any proposed models produce sufficient inhomogeneities. In this paper we provide an update on the measurement which first highlighted the issue: Lyman-α effective optical depth along high-z quasar lines of sight. We nearly triple on the previous sample size in such a study thanks to the cooperation of the DES-VHS, SHELLQs, and SDSS collaborations as well as new reductions and spectra. We find that a uniform UVB model is ruled out at 5.1 < z < 5.3, as well as higher redshifts, which is perplexing. We provide the first such measurements at z ~ 6. None of the numerical models we confronted to this data could reproduce the observed scatter.

  4. PC based alpha, beta and gamma counting system

    International Nuclear Information System (INIS)

    Bhattacharya, S.; Gopalakrishnan, K.R.; Bairi, B.R.

    1992-01-01

    In the field of radiation protection and safety a large number of samples have to be assayed for estimation of their radioactivity at various stages in nuclear fuel. A PC based alpha, beta and gamma counting system has been designed for the above application. The system is fully automatic and requires minimum of operator intervention. The main units in the system are detector and pulse processing electronics, sample changer and assembly and IBM PC interface and supporting software. The main function of interface is to control the sample changer which is basically loading and unloading of sample, data acquisition and further processing by software. The pulses from detector are analysed in a pulse shape discriminator. A pulse identified as an alpha, beta or gamma event is converted to digital pulse. These digital pulses are accumulated in the three channels on PC interface each corresponding to alpha, beta and gamma. The sample movements are controlled by interface depending upon sample position. The software has been developed so as to maintain user friendliness and convenience of the operator. Various selection modes for parameters and operation of system provide lot of flexibility in operation of the system. (author). 1 fig

  5. Diagnostics of the Solar Wind and Global Heliosphere with Lyman-α Emission Measurements

    Science.gov (United States)

    Provornikova, E. P.; Izmodenov, V. V.; Laming, J. M.; Strachan, L.; Wood, B. E.; Katushkina, O. A.; Ko, Y.-K.; Tun Beltran, S.; Chakrabarti, S.

    2018-02-01

    We propose to develop an instrument measuring full sky intensity maps and spectra of interplanetary Lyman-α emission to reveal the global solar wind variability and the nature of the heliosphere and the local interstellar medium.

  6. The Intergalactic Medium as a Cosmological Tool

    Energy Technology Data Exchange (ETDEWEB)

    Viel, Matteo, E-mail: viel@oats.inaf.i [INAF - Osservatorio Astronomico di Trieste, Via G.B. Tiepolo 11, I-34131 Trieste (Italy); INFN/National Institute for Nuclear Physics, Via Valerio 2, I-34127 Trieste (Italy)

    2009-10-15

    In this talk I will review the capabilities of high-resolution (UVES and Keck) and low resolution (Sloan Digital Sky Survey - SDSS) quasar (QSO) Lyman-alpha absorption spectra as cosmological tools to probe the dark matter distribution in the high redshift universe. I will first summarize the results in terms of cosmological parameters and then discuss consistency with the parameters derived from other large scale structure observable such as the Cosmic Microwave Background (CMB) and weak lensing surveys. When the Lyman-alpha forest data are combined with CMB data and the weak lensing results of the z-COSMOS survey the constraints are: sigma{sub 8}=0.800+-0.023, n{sub s}=0.971+-0.011OMEGA{sub m}=0.247+-0.016 (1-sigma error bars), in perfect agreement with the CMB results of WMAP year five alone. I will briefly address the importance of Lyman-alpha for constraining the neutrino mass fraction. Furthermore, I will present constraints on the mass of warm dark matter (WDM) particles derived from the Lyman-alpha flux power spectrum of 55 high-resolution HIRES Lyman-alpha forest spectra at 2.0=1.2keV (2sigma) if the WDM consists of early decoupled thermal relics and m{sub WDM}>=5.6keV (2sigma) for sterile neutrinos. Adding the SDSS Lyman-alpha flux power spectrum at 2.2=4keV and m{sub WDM}>=28keV (2sigma) for thermal relics and sterile neutrinos. These results improve previous findings by a factor two and are currently the tightest constraints on the coldness of cold dark matter. Finally, I will discuss: i) recent results for a mixture of cold and warm dark matter and the constraints for sterile neutrinos as dark matter candidates in a physically motivated framework (resonant production); ii) perspectives of cross-correlating the Lyman-alpha forest with convergence maps of the cosmic microwave background; iii) fitting of the flux probability distribution function.

  7. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

    Energy Technology Data Exchange (ETDEWEB)

    Rutkowski, Michael J.; Hayes, Matthew [Department of Astronomy, AlbaNova University Centre, Stockholm University, SE-10691 Stockholm (Sweden); Scarlata, Claudia; Mehta, Vihang [Minnesota Institute for Astrophysics, University of Minnesota, 116 Church Street SE, Minneapolis, MN 55455 (United States); Henry, Alaina; Hathi, Nimish; Koekemoer, Anton M. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Cohen, Seth; Windhorst, Rogier [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85281 (United States); Teplitz, Harry I. [Infrared Processing and Analysis Center, California Institute of Technology, Pasadena, CA 91125 (United States); Haardt, Francesco [DiSAT, Università dellInsubria, via Valleggio 11, I-22100 Como (Italy); Siana, Brian [Department of Physics, University of California, Riverside, CA 92521 (United States)

    2017-06-01

    Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f {sub esc} ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f {sub esc} ≲ 14.0%. Our observations are not deep enough to detect f {sub esc} ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong line ratios could be useful for pre-selecting LyC leakers at high redshift.

  8. The Lyman Continuum Escape Fraction of Emission Line-selected z ∼ 2.5 Galaxies Is Less Than 15%

    International Nuclear Information System (INIS)

    Rutkowski, Michael J.; Hayes, Matthew; Scarlata, Claudia; Mehta, Vihang; Henry, Alaina; Hathi, Nimish; Koekemoer, Anton M.; Cohen, Seth; Windhorst, Rogier; Teplitz, Harry I.; Haardt, Francesco; Siana, Brian

    2017-01-01

    Recent work suggests that strong emission line, star-forming galaxies (SFGs) may be significant Lyman continuum leakers. We combine archival Hubble Space Telescope broadband ultraviolet and optical imaging (F275W and F606W, respectively) with emission line catalogs derived from WFC3 IR G141 grism spectroscopy to search for escaping Lyman continuum (LyC) emission from homogeneously selected z ∼ 2.5 SFGs. We detect no escaping Lyman continuum from SFGs selected on [O ii] nebular emission ( N = 208) and, within a narrow redshift range, on [O iii]/[O ii]. We measure 1 σ upper limits to the LyC escape fraction relative to the non-ionizing UV continuum from [O ii] emitters, f _e_s_c ≲ 5.6%, and strong [O iii]/[O ii] > 5 ELGs, f _e_s_c ≲ 14.0%. Our observations are not deep enough to detect f _e_s_c ∼ 10% typical of low-redshift Lyman continuum emitters. However, we find that this population represents a small fraction of the star-forming galaxy population at z ∼ 2. Thus, unless the number of extreme emission line galaxies grows substantially to z ≳ 6, such galaxies may be insufficient for reionization. Deeper survey data in the rest-frame ionizing UV will be necessary to determine whether strong line ratios could be useful for pre-selecting LyC leakers at high redshift.

  9. Lyman Limit Absorbers in GALEX Spectra

    Science.gov (United States)

    Williger, Gerard M.; Haberzettl, Lutz G.; Ribaudo, Joseph; Kuchner, Marc J.; Burchett, Joseph; Clowes, Roger G.; Lauroesch, James T.; Mills, Brianna; Borden, Jeremy

    2018-01-01

    We describe the method and early results for crowdsourcing a search for low-redshift partial and complete Lyman Limit Systems (pLLSs and LLSs) in the GALEX spectral archive. LLSs have been found in large numbers at z>3 and traced to lower redshift through a relatively small number of QSO spectra from spaced-based telescopes. From a sample of 44 pLLSs and 11 LLSs at 0.1 = -0.32 +/- 0.07 and the low-metallicity portion centered at = -1.87 +/- 0.11.The GALEX spectral archive offers a vast dataset potentially containing hundreds of LLSs, which may be leveraged to search for such a bimodality and track its evolution within the unconstrained near-UV gap at 1data coverage and signal-to-noise ratio are highly variable, which hampers an automated search. We have therefore begun crowdsourcing a subset of the GALEX archive for LLSs and pLLSs via a Zooniverse project. Initially, undergraduate physics majors are performing a pilot project before releasing to citizen scientists in the public at large. We will then vet candidate systems and estimate column densities in a follow-up analysis. Upon assessing the accuracy of the physics majors’ identifications, the results will be used to devise a larger program with the help of the general public. The resulting data set would then provide the best available link between the HST-selected far-UV and ground-based pLLS+LLS samples and provide an ideal sample for consequent metallicity determinations.

  10. New development of EPICS based data acquisition system for H-Alpha diagnostic

    Energy Technology Data Exchange (ETDEWEB)

    Lee, Taegu, E-mail: glory@nfri.re.kr; Lee, Woongryol; Son, Souhun; Park, Jinseop

    2015-10-15

    Highlights: • The H-Alpha DAQ system was modified to measure the low current signal from the PMT. • We developed a new H-Alpha data acquisition system with a CPCI based digitizer. • We developed a signal conditioning box for converting the current to voltage. • The new signal condition box (SCB) has three input range level (400 nA, 1 μA and 2 μA). • It was successfully performed and stably operates more than the previous DAQ system. - Abstract: The H-Alpha diagnostic system has been developed to measure the line integrated intensity in the direction of toroidal and poloidal. The data acquisition (DAQ) system for H-Alpha diagnostics of the Korea Superconducting Tokamak Advanced Research (KSTAR) at the beginning of the first plasma in 2008 was developed with VME form factor digitizer in the Linux OS platform. The VME digitizer module of H-Alpha data acquisition system was modified to measure the low current signal from the photo-multiplier tubes (PMT). The input maximum current values of modified digitizer module are 400 nA and low current data is expressed as the value of the voltage between −10 V and +10 V. At first time, there was no problem to measure H-Alpha signal, but it could not measure the H-Alpha data signal as the KSTAR Plasma density increased. It exceeds digitizer input range, which means the H-Alpha signal is over 400 nA, so we should manually change the resistor on the digitizer board to measure the 400 nA over current. This is not easy to do and showed instability in the long time operation with high sampling data acquisition. In order to overcome these weak points, a new H-Alpha data acquisition system has been developed with a compact PCI (cPCI) based digitizer and a signal conditioning box for converting the current to voltage in the Linux OS platform. The new data acquisition system was developed based on Experimental Physics and Industrial Control System (EPICS) framework like other KSTAR diagnostics with standard framework (SFW

  11. The high-ion content and kinematics of low-redshift Lyman limit systems

    International Nuclear Information System (INIS)

    Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon; Lehner, Nicolas; Howk, J. Christopher; Tripp, Todd M.; Katz, Neal; Prochaska, J. Xavier; Werk, Jessica K.; O'Meara, John M.; Oppenheimer, Benjamin D.; Davé, Romeel

    2013-01-01

    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv 90 statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10 8.5-10.9 (r/150 kpc) 2 M ☉ , similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.

  12. The high-ion content and kinematics of low-redshift Lyman limit systems

    Energy Technology Data Exchange (ETDEWEB)

    Fox, Andrew J.; Tumlinson, Jason; Bordoloi, Rongmon [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Lehner, Nicolas; Howk, J. Christopher [Department of Physics, University of Notre Dame, 225 Nieuwland Science Hall, Notre Dame, IN 46556 (United States); Tripp, Todd M.; Katz, Neal [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Prochaska, J. Xavier; Werk, Jessica K. [UCO/Lick Observatory, University of California, Santa Cruz, CA 95064 (United States); O' Meara, John M. [Department of Physics, Saint Michael' s College, One Winooski Park, Colchester, VT 05439 (United States); Oppenheimer, Benjamin D. [Leiden Observatory, Leiden University, NL-2300 RA Leiden (Netherlands); Davé, Romeel, E-mail: afox@stsci.edu [University of the Western Cape, Robert Sobukwe Road, Bellville 7535 (South Africa)

    2013-12-01

    We study the high-ion content and kinematics of the circumgalactic medium around low-redshift galaxies using a sample of 23 Lyman limit systems (LLSs) at 0.08 < z < 0.93 observed with the Cosmic Origins Spectrograph on board the Hubble Space Telescope. In Lehner et al., we recently showed that low-z LLSs have a bimodal metallicity distribution. Here we extend that analysis to search for differences between the high-ion and kinematic properties of the metal-poor and metal-rich branches. We find that metal-rich LLSs tend to show higher O VI columns and broader O VI profiles than metal-poor LLSs. The total H I line width (Δv {sub 90} statistic) in LLSs is not correlated with metallicity, indicating that the H I kinematics alone cannot be used to distinguish inflow from outflow and gas recycling. Among the 17 LLSs with O VI detections, all but two show evidence of kinematic sub-structure, in the form of O VI-H I centroid offsets, multiple components, or both. Using various scenarios for how the metallicities in the high-ion and low-ion phases of each LLS compare, we constrain the ionized hydrogen column in the O VI phase to lie in the range log N(H II) ∼ 17.6-20. The O VI phase of LLSs is a substantial baryon reservoir, with M(high-ion) ∼ 10{sup 8.5-10.9} (r/150 kpc){sup 2} M {sub ☉}, similar to the mass in the low-ion phase. Accounting for the O VI phase approximately doubles the contribution of low-z LLSs to the cosmic baryon budget.

  13. SPECTROSCOPIC CONFIRMATION OF z {approx} 7 LYMAN BREAK GALAXIES: PROBING THE EARLIEST GALAXIES AND THE EPOCH OF REIONIZATION

    Energy Technology Data Exchange (ETDEWEB)

    Pentericci, L.; Fontana, A.; Castellano, M.; Grazian, A.; Boutsia, K.; Giallongo, E.; Maiolino, R.; Paris, D.; Santini, P. [INAF Osservatorio Astronomico di Roma, Via Frascati 33,00040 Monteporzio (Italy); Vanzella, E.; Cristiani, S. [INAF Osservatorio Astronomico di Trieste, Via G. B. Tiepolo 11, 34131 Trieste (Italy); Dijkstra, M. [Max-Planck-Institut fuer Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany); Dickinson, M. [National Optical Astronomy Observatory, P.O. Box 26732, Tucson, AZ 85726 (United States); Giavalisco, M. [Department of Astronomy, University of Massachusetts, 710 North Pleasant Street, Amherst, MA 01003 (United States); Moorwood, A., E-mail: laura.pentericci@oa-roma.inaf.it [European Southern Observatory, Karl-Schwarzschild Strasse, 85748 Garching (Germany)

    2011-12-20

    We present the final results from our ultra-deep spectroscopic campaign with FORS2 at the ESO Very Large Telescope (VLT) for the confirmation of z {approx_equal} 7 'z-band dropout' candidates selected from our VLT/Hawk-I imaging survey over three independent fields. In particular, we report on two newly discovered galaxies at redshift {approx}6.7 in the New Technology Telescope Deep Field. Both galaxies show an Ly{alpha} emission line with rest-frame equivalent widths (EWs) of the order of 15-20 A and luminosities of (2-4) Multiplication-Sign 10{sup 42} erg s{sup -1}. We also present the results of ultra-deep observations of a sample of i-dropout galaxies, from which we set a solid upper limit on the fraction of interlopers. Out of the 20 z-dropouts observed we confirm 5 galaxies at 6.6 < z < 7.1. This is systematically below the expectations drawn on the basis of lower redshift observations: in particular, there is a significant lack of objects with intermediate Ly{alpha} EWs (between 20 and 55 A). We conclude that the observed trend for the rising fraction of Ly{alpha} emission in Lyman break galaxies from z {approx} 3 to z {approx} 6 is most probably reversed from z {approx} 6 to z {approx} 7. Explaining the observed rapid change in the Ly{alpha} emitter fraction among the dropout population with reionization requires a fast evolution of the neutral fraction of hydrogen in the universe. Assuming that the universe is completely ionized at z = 6 and adopting a set of semi-analytical models, we find that our data require a change of the neutral hydrogen fraction of the order of {Delta}{chi}{sub H{sub i}}{approx}0.6 in a time {Delta}z {approx} 1, provided that the escape fraction does not increase dramatically over the same redshift interval.

  14. Investigating the Lyman photon escape in local starburst galaxies with the Cosmic Origins Spectrograph ★

    Science.gov (United States)

    Hernandez, Svea; Leitherer, Claus; Boquien, Médéric; Buat, Véronique; Burgarella, Denis; Calzetti, Daniela; Noll, Stefan

    2018-04-01

    We present a study of 7 star-forming galaxies from the Cosmic Evolution Survey (COSMOS) observed with the Cosmic Origins Spectrograph (COS) on board the Hubble Space Telescope (HST). The galaxies are located at relatively low redshifts, z ˜0.3, with morphologies ranging from extended and disturbed to compact and smooth. To complement the HST observations we also analyze observations taken with the VIMOS spectrograph on the Very Large Telescope (VLT). In our galaxy sample we identify three objects with double peak Lyman-α profiles similar to those seen in Green Pea compact galaxies and measure peak separations of 655, 374, and 275 km s-1. We measure Lyman-α escape fractions with values ranging between 5-13%. Given the low flux levels in the individual COS exposures we apply a weighted stacking approach to obtain a single spectrum. From this COS combined spectrum we infer upper limits for the absolute and relative Lyman continuum escape fractions of f_abs(LyC) = 0.4^{+10.1}_{-0.4}% and f_res(LyC) = 1.7^{+15.2}_{-1.7}%, respectively. Finally, we find that most of these galaxies have moderate UV and optical SFRs (SFRs ≲ 10 M⊙ yr-1).

  15. The Lyman Alpha Reference Sample: Extended Lyman Alpha Halos Produced at Low Dust Content

    Czech Academy of Sciences Publication Activity Database

    Hayes, M.; Oestlin, G.; Schaerer, D.; Verhamme, A.; Mas-Hesse, J. M.; Adamo, A.; Atek, H.; Cannon, J.M.; Duval, F.; Guaita, L.; Herenz, E.Ch.; Kunth, D.; Laursen, P.; Melinder, J.; Orlitová, Ivana; Oti-Floranes, H.; Sandberg, A.

    2013-01-01

    Roč. 765, č. 2 (2013), L27/1-L27/6 ISSN 2041-8205 Institutional support: RVO:67985815 Keywords : cosmology observations * galaxies * evolution Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 5.602, year: 2013

  16. Laboratory system for alpha particle spectroscopy

    International Nuclear Information System (INIS)

    Dean, J.R.; Chiu, N.W.

    1987-03-01

    An automated alpha particle spectroscopy system has beeen designed and fabricated. It consists of two major components, the automatic sample changer and the controller/data acquisition unit. It is capable of unattended analysis of ten samples for up to 65,000 seconds per sample

  17. Alpha: A real-time decentralized operating system for mission-oriented system integration and operation

    Science.gov (United States)

    Jensen, E. Douglas

    1988-01-01

    Alpha is a new kind of operating system that is unique in two highly significant ways. First, it is decentralized transparently providing reliable resource management across physically dispersed nodes, so that distributed applications programming can be done largely as though it were centralized. And second, it provides comprehensive, high technology support for real-time system integration and operation, an application area which consists predominately of aperiodic activities having critical time constraints such as deadlines. Alpha is extremely adaptable so that it can be easily optimized for a wide range of problem-specific functionality, performance, and cost. Alpha is the first systems effort of the Archons Project, and the prototype was created at Carnegie-Mellon University directly on modified Sun multiprocessor workstation hardware. It has been demonstrated with a real-time C(sup 2) application. Continuing research is leading to a series of enhanced follow-ons to Alpha; these are portable but initially hosted on Concurrent's MASSCOMP line of multiprocessor products.

  18. Portable wireless neurofeedback system of EEG alpha rhythm enhances memory.

    Science.gov (United States)

    Wei, Ting-Ying; Chang, Da-Wei; Liu, You-De; Liu, Chen-Wei; Young, Chung-Ping; Liang, Sheng-Fu; Shaw, Fu-Zen

    2017-11-13

    Effect of neurofeedback training (NFT) on enhancement of cognitive function or amelioration of clinical symptoms is inconclusive. The trainability of brain rhythm using a neurofeedback system is uncertainty because various experimental designs are used in previous studies. The current study aimed to develop a portable wireless NFT system for alpha rhythm and to validate effect of the NFT system on memory with a sham-controlled group. The proposed system contained an EEG signal analysis device and a smartphone with wireless Bluetooth low-energy technology. Instantaneous 1-s EEG power and contiguous 5-min EEG power throughout the training were developed as feedback information. The training performance and its progression were kept to boost usability of our device. Participants were blinded and randomly assigned into either the control group receiving random 4-Hz power or Alpha group receiving 8-12-Hz power. Working memory and episodic memory were assessed by the backward digital span task and word-pair task, respectively. The portable neurofeedback system had advantages of a tiny size and long-term recording and demonstrated trainability of alpha rhythm in terms of significant increase of power and duration of 8-12 Hz. Moreover, accuracies of the backward digital span task and word-pair task showed significant enhancement in the Alpha group after training compared to the control group. Our tiny portable device demonstrated success trainability of alpha rhythm and enhanced two kinds of memories. The present study suggest that the portable neurofeedback system provides an alternative intervention for memory enhancement.

  19. Response approach to the squeezed-limit bispectrum: application to the correlation of quasar and Lyman-α forest power spectrum

    Energy Technology Data Exchange (ETDEWEB)

    Chiang, Chi-Ting [C.N. Yang Institute for Theoretical Physics, Stony Brook University, Stony Brook, NY 11794 (United States); Cieplak, Agnieszka M.; Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton, NY 11375 (United States); Schmidt, Fabian, E-mail: chi-ting.chiang@stonybrook.edu, E-mail: acieplak@bnl.gov, E-mail: fabians@mpa-garching.mpg.de, E-mail: anze@bnl.gov [Max-Planck-Institut für Astrophysik, Karl-Schwarzschild-Str. 1, 85741 Garching (Germany)

    2017-06-01

    The squeezed-limit bispectrum, which is generated by nonlinear gravitational evolution as well as inflationary physics, measures the correlation of three wavenumbers, in the configuration where one wavenumber is much smaller than the other two. Since the squeezed-limit bispectrum encodes the impact of a large-scale fluctuation on the small-scale power spectrum, it can be understood as how the small-scale power spectrum ''responds'' to the large-scale fluctuation. Viewed in this way, the squeezed-limit bispectrum can be calculated using the response approach even in the cases which do not submit to perturbative treatment. To illustrate this point, we apply this approach to the cross-correlation between the large-scale quasar density field and small-scale Lyman-α forest flux power spectrum. In particular, using separate universe simulations which implement changes in the large-scale density, velocity gradient, and primordial power spectrum amplitude, we measure how the Lyman-α forest flux power spectrum responds to the local, long-wavelength quasar overdensity, and equivalently their squeezed-limit bispectrum. We perform a Fisher forecast for the ability of future experiments to constrain local non-Gaussianity using the bispectrum of quasars and the Lyman-α forest. Combining with quasar and Lyman-α forest power spectra to constrain the biases, we find that for DESI the expected 1−σ constraint is err[ f {sub NL}]∼60. Ability for DESI to measure f {sub NL} through this channel is limited primarily by the aliasing and instrumental noise of the Lyman-α forest flux power spectrum. The combination of response approach and separate universe simulations provides a novel technique to explore the constraints from the squeezed-limit bispectrum between different observables.

  20. Determination of magnetic field direction in tokamaks from laser-induced Lyman-α fluorescence

    International Nuclear Information System (INIS)

    Voslamber, D.

    1988-04-01

    Resonant laser scattering in the Lyman-α line of hydrogen is investigated as a possible tool for measuring the magnetic field direction in tokamak plasmas. The method is based on the depolarisation-dependence of the scattering process. Limitations arising from depolarising collisions are studied in detail by employing a previously developed theory for the collisional redistribution of light. An error analysis is performed to derive the expected experimental precision under various plasma conditions and for laser energies ranging between 1 micronJ and 10 mJ. This analysis also includes the measurement of neutral hydrogen densities. It is shown that with presently available laser powers application of the method would be restricted to the border regions of the plasma. Application to the central regions would require further developments in laser technology, especially with regard to higher powers at the wavelength of Lyman-α and (or) to fast repetition rates

  1. Detection of Lyman/alpha emission from a DLA galaxy

    DEFF Research Database (Denmark)

    Moller, P.; Fynbo, Johan Peter Uldall; Fall, S.M

    2004-01-01

    HIGH-REDSHIFT; BREAK GALAXIES; STARFORMATION; DISK GALAXIES; METAL ENRICHMENT; HOST GALAXY; ABSORPTION; ABSORBER; SYSTEMS; SPECTROSCOPY......HIGH-REDSHIFT; BREAK GALAXIES; STARFORMATION; DISK GALAXIES; METAL ENRICHMENT; HOST GALAXY; ABSORPTION; ABSORBER; SYSTEMS; SPECTROSCOPY...

  2. The Development of Replicated Optical Integral Field Spectrographs and their Application to the Study of Lyman-alpha Emission at Moderate Redshifts

    Science.gov (United States)

    Chonis, Taylor Steven

    In the upcoming era of extremely large ground-based astronomical telescopes, the design of wide-field spectroscopic survey instrumentation has become increasingly complex due to the linear growth of instrument pupil size with telescope diameter for a constant spectral resolving power. The upcoming Visible Integral field Replicable Unit Spectrograph (VIRUS), a baseline array of 150 copies of a simple integral field spectrograph that will be fed by 3:36 x 104 optical fibers on the upgraded Hobby-Eberly Telescope (HET) at McDonald Observatory, represents one of the first uses of large-scale replication to break the relationship between instrument pupil size and telescope diameter. By dividing the telescope's field of view between a large number of smaller and more manageable instruments, the total information grasp of a traditional monolithic survey spectrograph can be achieved at a fraction of the cost and engineering complexity. To highlight the power of this method, VIRUS will execute the HET Dark Energy Experiment (HETDEX) and survey & 420 degrees2 of sky to an emission line flux limit of ˜ 10-17 erg s-1 cm -2 to detect ˜ 106 Lyman-alpha emitting galaxies (LAEs) as probes of large-scale structure at redshifts of 1:9 production of the suite of volume phase holographic (VPH) diffraction gratings for VIRUS is presented, which highlights the challenge and success associated with producing of a very large number of highly customized optical elements whose performance is crucial to meeting the efficiency requirements of the spectrograph system. To accommodate VIRUS, the HET is undergoing a substantial wide-field upgrade to increase its field of view to 22' in diameter. The previous HET facility Low Resolution Spectrograph (LRS), which was directly fed by the telescope's previous spherical aberration corrector, must be removed from the prime focus instrument package as a result of the telescope upgrades and instead be fiber-coupled to the telescope focal plane. For a

  3. Dark energy and curvature from a future baryonic acoustic oscillation survey using the Lyman-α forest

    International Nuclear Information System (INIS)

    McDonald, Patrick; Eisenstein, Daniel J.

    2007-01-01

    We explore the requirements for a Lyman-α forest survey designed to measure the angular diameter distance and Hubble parameter at 2 or approx. 250 spectrograph is sufficient to measure both the radial and transverse oscillation scales to 1.4% from the Lyα forest (or better, if fainter magnitudes and possibly Lyman-break galaxies can be used). At fixed integration time and in the sky-noise-dominated limit, a wider, noisier survey is generally more efficient; the only fundamental upper limit on noise being the need to identify a quasar and find a redshift. Because the Lyα forest is much closer to linear and generally better understood than galaxies, systematic errors are even less likely to be a problem

  4. Inhibition of systemic inflammation by central action of the neuropeptide alpha-melanocyte- stimulating hormone.

    Science.gov (United States)

    Delgado Hernàndez, R; Demitri, M T; Carlin, A; Meazza, C; Villa, P; Ghezzi, P; Lipton, J M; Catania, A

    1999-01-01

    The neuropeptide alpha-melanocyte stimulating hormone (alpha-MSH) reduces fever and acute inflammation in the skin when administered centrally. The aim of the present research was to determine whether central alpha-MSH can also reduce signs of systemic inflammation in mice with endotoxemia. Increases in serum tumor necrosis factor-alpha and nitric oxide, induced by intraperitoneal administration of endotoxin, were modulated by central injection of a small concentration of alpha-MSH. Inducible nitric oxide synthase (iNOS) activity and iNOS mRNA in lungs and liver were likewise modulated by central alpha-MSH. Lung myeloperoxidase activity, a marker of neutrophil infiltration, was increased in endotoxemic mice; the increase was significantly less in lungs of mice treated with central alpha-MSH. Intraperitoneal administration of the small dose of alpha-MSH that was effective centrally did not alter any of the markers of inflammation. In experiments using immunoneutralization of central alpha-MSH, we tested the idea that endogenous peptide induced within the brain during systemic inflammation modulates host responses to endotoxic challenge in peripheral tissues. The data showed that proinflammatory agents induced by endotoxin in the circulation, lungs, and liver were significantly greater after blockade of central alpha-MSH. The results suggest that anti-inflammatory influences of neural origin that are triggered by alpha-MSH could be used to treat systemic inflammation.

  5. Using Lyman-alpha to detect galaxies that leak Lyman continuum

    Czech Academy of Sciences Publication Activity Database

    Verhamme, A.; Orlitová, Ivana; Schaerer, D.; Hayes, M.

    2015-01-01

    Roč. 578, June (2015), A7/1-A7/13 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GP14-20666P Institutional support: RVO:67985815 Keywords : line profiles * radiative transfer * galaxies Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  6. The calculation of the detection efficiency in the calibration of gross alpha-beta systems

    International Nuclear Information System (INIS)

    Marian Romeo Calin; Ileana Radulescu; Alexandru Erminiu Druker

    2013-01-01

    This paper presents a method for efficiency calibration of a measuring alpha-beta system PROTEAN ORTEC, MPC-2000-DP, using standard radioactive sources. The system is used to measure gross alpha-beta activity concentrations in environmental samples. The calculated efficiencies of detection were subsequently introduced in the system for two working geometries: measuring geometry-gross alpha-beta ε α g = 31,37 ± 0.25 (%)-the alpha efficiency and ε β g 44.94 ± 0.69 (%)-the beta efficiency, where the spillover factor is X talk g = 25.59 ± 0.50 (%) and measuring geometry up alpha-beta ε α u 36.23 ± 0.29 (%)-the alpha efficiency and ε β u = 48.53 ± 0.74 (%)-the beta efficiency, where the spillover factor is X talk u 31.08 ± 0.60 (%). (author)

  7. Quasar Absorption in the UV: Probing the Intergalactic Medium

    Science.gov (United States)

    Weinberg, David; Katz, Neal

    1998-01-01

    The purpose of this project is to model the low-redshift Lyman-alpha forest and exploration of the relation between Lyman-alpha absorbers and galaxies. This paper shows that the simulation models that are so successful at explaining properties of the high-redshift forest also account for the most important results of observational studies of the low-redshift forest, from HST (especially the Quasar Absorption Line Key Project) and ground-based follow-up.

  8. The Sunburst Arc: Direct Lyman α escape observed in the brightest known lensed galaxy

    Science.gov (United States)

    Rivera-Thorsen, T. E.; Dahle, H.; Gronke, M.; Bayliss, M.; Rigby, J. R.; Simcoe, R.; Bordoloi, R.; Turner, M.; Furesz, G.

    2017-11-01

    We present rest-frame ultraviolet and optical spectroscopy of the brightest lensed galaxy yet discovered, at redshift z = 2.4. The source reveals a characteristic triple-peaked Lyman α profile that has been predicted in various theoretical works, but to our knowledge has not been unambiguously observed previously. The feature is well fit by a superposition of two components: a double-peak profile emerging from substantial radiative transfer, and a narrow, central component resulting from directly escaping Lyman α photons, but it is poorly fit by either component alone. We demonstrate that the feature is unlikely to contain contamination from nearby sources, and that the central peak is unaffected by radiative transfer effects except for very slight absorption. The feature is detected at signal-to-noise ratios exceeding 80 per pixel at line center, and bears strong resemblance to synthetic profiles predicted by numerical models. Based on observations obtained at the Magellan-I (Baade) Telescope at Las Campanas Observatory, Chile.

  9. A possible connection between the spin temperature of damped Lyman α absorption systems and star formation history

    Science.gov (United States)

    Curran, S. J.

    2017-09-01

    We present a comprehensive analysis of the spin temperature/covering factor degeneracy, Tspin/f, in damped Lyman α absorption systems. By normalizing the upper limits and including these via a survival analysis, there is, as previously claimed, an apparent increase in Tspin/f with redshift at zabs ≳ 1. However, when we account for the geometry effects of an expanding Universe, neglected by the previous studies, this increase in Tspin at zabs ≳ 1 is preceded by a decrease at zabs ≲ 1. Using high resolution radio images of the background continuum sources, we can transform the Tspin/f degeneracy to T_spin/d_abs^{ 2}, where dabs is the projected linear size of the absorber. Again, there is no overall increase with redshift, although a dip at zabs ≈ 2 persists. Furthermore, we find d_abs^{ 2}/T_spin to follow a similar variation with redshift as the star formation rate, ψ*. This suggests that, although the total hydrogen column density, N_{H I}, shows little relation to ψ*, the fraction of the cold neutral medium, \\int τ_obs dv/N_{H I}, may. Therefore, further efforts to link the neutral gas with the star formation history should also consider the cool component of the gas.

  10. The Bulk Elemental Composition of any Terrestrial Planets in the Alpha Centauri System

    Science.gov (United States)

    Lineweaver, C. H.; Schonberger, B. F. G.; Robles, J. A.

    2010-04-01

    Based on the devolatilization patterns in the solar system, and on the differences in the chemical compositions of the Sun and Alpha Centauri, we make estimates of the chemical composition of any Earth-like planets in the Alpha Centauri system.

  11. Cryogenic Microcalorimeter System for Ultra-High Resolution Alpha-Particle Spectrometry

    Science.gov (United States)

    Croce, M. P.; Bacrania, M. K.; Hoover, A. S.; Rabin, M. W.; Hoteling, N. J.; LaMont, S. P.; Plionis, A. A.; Dry, D. E.; Ullom, J. N.; Bennett, D. A.; Horansky, R. D.; Kotsubo, V.; Cantor, R.

    2009-12-01

    Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ˜15-μK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis. This paper will discuss design and operation of our microcalorimeter alpha-particle spectrometer, and will show recent results.

  12. Cryogenic microcalorimeter system for ultra-high resolution alpha-particle spectrometry

    International Nuclear Information System (INIS)

    Rabin, Michael W.; Hoover, Andrew S.; Bacrania, Minesh K.; Croce, Mark P.; Hoteling, N.J.; Lamont, S.P.; Plionis, A.A.; Dry, D.E.; Ullom, J.N.; Bennett, D.A.; Horansky, R.; Kotsubo, V.; Cantor, R.

    2009-01-01

    Microcalorimeters have been shown to yield unsurpassed energy resolution for alpha spectrometry, up to 1.06 keV FWHM at 5.3 MeV. These detectors use a superconducting transition-edge sensor (TES) to measure the temperature change in an absorber from energy deposited by an interacting alpha particle. Our system has four independent detectors mounted inside a liquid nitrogen/liquid helium cryostat. An adiabatic demagnetization refrigerator (ADR) cools the detector stage to its operating temperature of 80 mK. Temperature regulation with ∼15 uK peak-to-peak variation is achieved by PID control of the ADR. The detectors are voltage-biased, and the current signal is amplified by a commercial SQUID readout system and digitized for further analysis, This paper will discuss design and operation of our microcalorimeter alpha spectrometer, and will show recent results.

  13. Frequency tripling with multimode-lasers

    International Nuclear Information System (INIS)

    Langer, H.; Roehr, H.; Wrobel, W.G.

    1978-10-01

    The presence of different modes with random phases in a laser beam leads to fluctuations in nonlinear optical interactions. This paper describes the influence of the linewidth of a dye laser on the generation of intensive Lyman-alpha radiation by frequency tripling. Using this Lyman-alpha source for resonance scattering on strongly doppler-broadened lines in fusion plasmas the detection limit of neutral hydrogen is nearly two orders higher with the multimode than the singlemode dye laser. (orig.) [de

  14. Constraining Lyman continuum escape using Machine Learning

    Science.gov (United States)

    Giri, Sambit K.; Zackrisson, Erik; Binggeli, Christian; Pelckmans, Kristiaan; Cubo, Rubén; Mellema, Garrelt

    2018-05-01

    The James Webb Space Telescope (JWST) will observe the rest-frame ultraviolet/optical spectra of galaxies from the epoch of reionization (EoR) in unprecedented detail. While escaping into the intergalactic medium, hydrogen-ionizing (Lyman continuum; LyC) photons from the galaxies will contribute to the bluer end of the UV slope and make nebular emission lines less prominent. We present a method to constrain leakage of the LyC photons using the spectra of high redshift (z >~ 6) galaxies. We simulate JWST/NIRSpec observations of galaxies at z =6-9 by matching the fluxes of galaxies observed in the Frontier Fields observations of galaxy cluster MACS-J0416. Our method predicts the escape fraction fesc with a mean absolute error Δfesc ~ 0.14. The method also predicts the redshifts of the galaxies with an error .

  15. GALEX-SELECTED LYMAN BREAK GALAXIES AT z {approx} 2: COMPARISON WITH OTHER POPULATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Haberzettl, L.; Williger, G. [Department of Physics and Astronomy, University of Louisville, Louisville KY 20492 (United States); Lehnert, M. D. [GEPI, Observatoire de Paris, UMR 8111 du CNRS, 5 Place Jules Janssen, 92195 Meudon (France); Nesvadba, N. [Institut d' Astrophysique Spatiale, CNRS, Universite Paris-Sud, Bat. 120-121, 91405 Orsay (France); Davies, L. [Department of Physics, H H Wills Physics Laboratory, University of Bristol, Tyndall Avenue, Bristol BS8 1TL (United Kingdom)

    2012-01-20

    We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 {<=} z {<=} 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and find the NUV data to provide greater efficiency for selecting star-forming galaxies. We estimate LBG candidate ages, masses, star formation rates, and extinction from fitting PEGASE synthesis evolution models. We find that about 20% of our LBG candidates are comparable to infrared-luminous LBGs or submillimeter galaxies which are thought to be precursors of massive elliptical galaxies today. Overall, we can show that although BM/BX and BzK methods do identify star-forming galaxies at z {approx} 2, the sample they provide biases against those star-forming galaxies which are more massive and contain sizeable red stellar populations. A true Lyman break criterion at z {approx} 2 is therefore more directly comparable to the populations found at z {approx} 3, which does contain a red fraction.

  16. GALEX-SELECTED LYMAN BREAK GALAXIES AT z ∼ 2: COMPARISON WITH OTHER POPULATIONS

    International Nuclear Information System (INIS)

    Haberzettl, L.; Williger, G.; Lehnert, M. D.; Nesvadba, N.; Davies, L.

    2012-01-01

    We present results of a search for bright Lyman break galaxies (LBGs) at 1.5 ≤ z ≤ 2.5 in the GOODS-S field using an NUV-dropout technique in combination with color selection. We derived a sample of 73 LBG candidates. We compare our selection efficiencies to BM/BX and BzK methods (techniques solely based on ground-based data sets), and find the NUV data to provide greater efficiency for selecting star-forming galaxies. We estimate LBG candidate ages, masses, star formation rates, and extinction from fitting PEGASE synthesis evolution models. We find that about 20% of our LBG candidates are comparable to infrared-luminous LBGs or submillimeter galaxies which are thought to be precursors of massive elliptical galaxies today. Overall, we can show that although BM/BX and BzK methods do identify star-forming galaxies at z ∼ 2, the sample they provide biases against those star-forming galaxies which are more massive and contain sizeable red stellar populations. A true Lyman break criterion at z ∼ 2 is therefore more directly comparable to the populations found at z ∼ 3, which does contain a red fraction.

  17. CLASP: A UV Spectropolarimeter on a Sounding Rocket for Probing theChromosphere-Corona Transition Regio

    Science.gov (United States)

    Ishikawa, Ryohko; Kano, Ryouhei; Winebarger, Amy; Auchere, Frederic; Trujillo Bueno, Javier; Bando, Takamasa; Narukage, Noriyuki; Kobayashi, Ken; Katsukawa, Yukio; Kubo, Masahito; Ishikawa, Shin-nosuke; Giono, Gabriel; Tsuneta, Saku; Hara, Hirohisa; Suematsu, Yoshinori; Shimizu, Toshifumi; Sakao, Taro; Ichimoto, Kiyoshi; Cirtain, Jonathan; De Pontieu, Bart; Casini, Roberto; Manso Sainz, Rafael; Asensio Ramos, Andres; Stepan, Jiri; Belluzzi, Luca

    2015-08-01

    The wish to understand the energetic phenomena of the outer solar atmosphere makes it increasingly important to achieve quantitative information on the magnetic field in the chromosphere-corona transition region. To this end, we need to measure and model the linear polarization produced by scattering processes and the Hanle effect in strong UV resonance lines, such as the hydrogen Lyman-alpha line. A team consisting of Japan, USA, Spain, France, and Norway has been developing a sounding rocket experiment called the Chromospheric Lyman-alpha Spectro-Polarimeter (CLASP). The aim is to detect the scattering polarization produced by anisotropic radiation pumping in the hydrogen Lyman-alpha line (121.6 nm), and via the Hanle effect to try to constrain the magnetic field vector in the upper chromosphere and transition region. In this talk, we will present an overview of our CLASP mission, its scientific objectives, ground tests made, and the latest information on the launch planned for the Summer of 2015.

  18. The z~4 Lyman Break Galaxies: Colors and Theoretical Predictions

    Science.gov (United States)

    Idzi, Rafal; Somerville, Rachel; Papovich, Casey; Ferguson, Henry C.; Giavalisco, Mauro; Kretchmer, Claudia; Lotz, Jennifer

    2004-01-01

    We investigate several fundamental properties of z~4 Lyman break galaxies by comparing observations with the predictions of a semianalytic model based on the cold dark matter theory of hierarchical structure formation. We use a sample of B435-dropouts from the Great Observatories Origins Deep Survey and complement the Advanced Camera for Surveys optical B435, V606, i775, and z850 data with the Very Large Telescope Infrared Spectrometer and Array Camera J, H, and Ks observations. We extract B435-dropouts from our semianalytic mock catalog using the same color criteria and magnitude limits that were applied to the observed sample. We find that the i775-Ks colors of the model-derived and observed B435-dropouts are in good agreement. However, we find that the i775-z850 colors differ significantly, indicating perhaps that either too little dust or an incorrect extinction curve has been used. Motivated by the reasonably good agreement between the model and observed data, we present predictions for the stellar masses, star formation rates, and ages for the z~4 Lyman break sample. We find that according to our model, the color selection criteria used to select our z~4 sample surveys 67% of all galaxies at this epoch down to z850Universities for Research in Astronomy (AURA), Inc., under NASA contract NAS5-26555. Based on observations collected at the European Southern Observatory, Chile (ESO programmes 168.A-0485, 64.0-0643, 66.A-0572, and 68.A-0544).

  19. Relative Contribution of the Hydrogen 2 s Two-Photon Decay and Lyman- α Escape Channels during the Epoch of Cosmological Recombination

    Science.gov (United States)

    Rubiño-Martin, J. A.; Sunyaev, R. A.

    2018-01-01

    We discuss the evolution of the ratio in number of recombinations due to 2 s two photon escape and due to the escape of Lyman- α photons from the resonance during the epoch of cosmological recombination, within the width of the last scattering surface and near its boundaries. We discuss how this ratio evolves in time, and how it defines the profile of the Lyman- α line in the spectrum of CMB. One of the key reasons for explaining its time dependence is the strong overpopulation of the 2 p level relative to the 2 s level at redshifts z ≲ 750.

  20. Automated multispectra alpha spectrometer and data reduction system

    International Nuclear Information System (INIS)

    Hochel, R.C.

    1975-12-01

    A complete hardware and software package for the accumulation and rapid analysis of multiple alpha pulse height spectra has been developed. The system utilizes a 4096-channel analyzer capable of accepting up to sixteen inputs from solid-state surface barrier detectors via mixer-router modules. The analyzer is interfaced to a desk-top programmable calculator and thermal line printer. A chained software package including spectrum printout, peak analysis, plutonium-238 and plutonium-239 data reduction, and automatic energy calibration routines was written. With the chained program a complete printout, peak analysis, and plutonium data reduction of a 512-channel alpha spectrum are obtained in about three minutes with an accuracy within five percent of hand analyses

  1. Lyman-alpha spectral properties of five newly discovered Lyman continuum emitters

    Czech Academy of Sciences Publication Activity Database

    Verhamme, A.; Orlitová, Ivana; Schaerer, D.; Izotov, Y.I.; Worseck, G.; Thuan, T.X.; Guseva, N.G.

    2017-01-01

    Roč. 597, January (2017), A13/1-A13/13 E-ISSN 1432-0746 R&D Projects: GA ČR(CZ) GP14-20666P Institutional support: RVO:67985815 Keywords : radiative transfer * dark ages * reionization Subject RIV: BN - Astronomy , Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 5.014, year: 2016

  2. Chemical reactivity of {alpha}-isosaccharinic acid in heterogeneous alkaline systems

    Energy Technology Data Exchange (ETDEWEB)

    Glaus, M. A.; Loon, L. R. Van

    2009-05-15

    Cellulose degradation under alkaline conditions is of relevance for the mobility of many radionuclides in the near-field of a cementitious repository for radioactive waste, because metal-binding degradation products may be formed. Among these, {alpha}- isosaccharinic acid ({alpha}-ISA) is the strongest complexant. The prediction of the equilibrium concentration of {alpha}-ISA in cement pore water is therefore an important step in the assessment of the influence of cellulose degradation products on the speciation of radionuclides in such environments. The present report focuses on possible chemical transformation reactions of {alpha}-ISA in heterogeneous alkaline model systems containing either Ca(OH){sub 2} or crushed hardened cement paste. The transformation reactions were monitored by measuring the concentration of {alpha}-ISA by high performance anion exchange chromatography and the formation of reaction products by high performance ion exclusion chromatography. The overall loss of organic species from solution was monitored by measuring the concentration of non-purgeable organic carbon. The reactions were examined in diluted and compacted suspensions, at either 25 {sup o}C or 90 {sup o}C, and under anaerobic atmospheres obtained by various methods. It was found that {alpha}-ISA was transformed under all conditions tested to some extent. Reaction products, such as glycolate, formate, lactate and acetate, all compounds with less complexing strength than {alpha}-ISA, were detected. The amount of reaction products identified by the chromatographic technique applied was {approx} 50 % of the amount of {alpha}-ISA reacted. Sorption of {alpha}-ISA to Ca(OH){sub 2} contributed only to a minor extent to the loss of {alpha}-ISA from the solution phase. As the most important conclusion of the present work it was demonstrated that the presence of oxidising agents had a distinctive influence on the turnover of {alpha}-ISA. Under aerobic conditions {alpha}-ISA was

  3. Improvement and automatization of a proportional alpha-beta counting system - FAG

    International Nuclear Information System (INIS)

    German, U.; Levinson, S.; Pelled, O.; Shemesh, Y.; Assido, H.

    1997-01-01

    An alpha and beta counting system - FAG*, for planchette samples is operated at the Health Physics department's laboratory of the NRCN. The original operation mode of the system was based on manual tasks handled by the FHT1 100 electronics. An option for a basic computer keyboard operation was available too. A computer with an appropriate I/O card was connected to the system and a new operating program was developed which enables full automatic control of the various components. The program includes activity calculations and statistical checks as well as data management. A bar-code laser system for sample number reading was integrated into the Alpha-Beta automatic counting system. The sample identification by means of an attached bar-code label enables unmistakable and reliable attribution of results to the counted sample. authors)

  4. Cosmological Evolution of QSO Absorption Systems

    Science.gov (United States)

    Stengler-Larrea, Erik

    1995-08-01

    First, the evolution with cosmic time of the hydrogen clouds which produce the Lyman-alpha absorption lines is studied in dependence on the strength of these lines. From the analysis it is concluded that the results show no evidence of a dependence in the sense of stronger lines evolving faster, although for the resolution at which the used observations were done, it can not be ruled out. Within the same analysis, a distribution of the Doppler parameter of the lines was obtained, with large values and a wide spread. This parameter being an indicator of the gas temperature, this result is in accordance with high temperatures and, consequently, large ionised fractions and a large fraction of the baryonic matter of the universe being associated with these clouds. However, recent high resolution studies seem to reveal that much lower temperatures are characteristic of the clouds. The main content of this thesis, however, focuses on the redshift evolution of the absorbing systems producing absorption at the Lyman limit and of the amount of CIV producing CIV absorption lines. Regarding the CIV absorbers, previous predictions on the effects underlying their redshift distribution pointed to an increase with redshift of the absorbing column densities. In this thesis the first direct measurements of such column densities by profile fitting of a large number of absorption systems (73) are presented, confirming the predictions of a decrease of at least a factor of 3 between z=1.5 and z=3.0. The study on the evolution of Lyman limit absorption systems (LLSs) puts an end to previous discrepancies between the results of different groups. Both a smooth single power law dependence of the LLS number density on redshift indicating no evolution in number density for 0.4 Team of the HST Key Project on QSO absorption lines, and in particular to estimate the necessary exposure times, the magnitudes of several of these objects had to be re-measured. The acquisition of their images and the

  5. Continuous emission from the gaseous nebula beyond the Lyman limit

    International Nuclear Information System (INIS)

    Bolgova, G.T.; Khromov, G.S.

    1975-01-01

    Models of spherically-symmetric isothermic hydrogen nebula with an exciting star in the centre are considered. Spectra and energies of diffuse radiation of nebula and of direct radiation of its kernel are calculated in the Lyman continuum for the external boundary of the object. The spectrum of the diffuse radiation is shown to be to a great extent invariant in relation to all parameters of models except for Tsub(e). The total loss in energy of Lsub(c)-radiation of kernel through the external border of the ionized nebula, amounts to 20-30% in the average even at a considerable optical thickness of the object tausub(0). The greater part of this energy is transferred via direct ionizing radiation, though the relative contribution of the diffuse Lsub(c)-radiation of nebula reaches 30% at low temperatures of the exciting star and at large tausub(0). The results of this work may be applied to calculating the energy balance of the star-nebula system, the heating of dust particles and ionization of the neighbouring interstellar medium, and also for determining the conditions of observation of the far ultra-violet radiation of similar objects

  6. A manual low background alpha beta counting system

    Energy Technology Data Exchange (ETDEWEB)

    Levison, S; German, U; Peled, O; Turgeman, S; Vangrovitz, U; Tirosh, D; Piestum, S; Assido, H [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    An Alpha and Beta counting system consisting of a micro controller-based electronic unit and detectors assembly was developed. The radiation detection unit consists of two proportional detectors (a main detector and a cosmic-ray guard detector) which can be easily disassembled for decontamination or repair. The detectors are mounted in a manual operating sample changer shielded by 5 cm of lead. Simplicity of maintenance and functional operation were taken into consideration in the design. The electronic unit supplies the high voltage and enables the operational functions including controls anti alarms. Calculations of net cpm of Alpha and Beta counting are displayed and can be printed. RS-232 communication option enables connection to a computer and operation of more sophisticated programs for calculations and data storage in the future (authors).

  7. A manual low background alpha beta counting system

    International Nuclear Information System (INIS)

    Levison, S.; German, U.; Peled, O.; Turgeman, S.; Vangrovitz, U.; Tirosh, D.; Piestum, S.; Assido, H.

    1996-01-01

    An Alpha and Beta counting system consisting of a micro controller-based electronic unit and detectors assembly was developed. The radiation detection unit consists of two proportional detectors (a main detector and a cosmic-ray guard detector) which can be easily disassembled for decontamination or repair. The detectors are mounted in a manual operating sample changer shielded by 5 cm of lead. Simplicity of maintenance and functional operation were taken into consideration in the design. The electronic unit supplies the high voltage and enables the operational functions including controls anti alarms. Calculations of net cpm of Alpha and Beta counting are displayed and can be printed. RS-232 communication option enables connection to a computer and operation of more sophisticated programs for calculations and data storage in the future (authors)

  8. The Lyman alpha reference sample VI. Lyman alpha escape from the edge-on disk galaxy Mrk 1486

    Czech Academy of Sciences Publication Activity Database

    Duval, F.; Ostlin, G.; Hayes, M.; Zackrisson, E.; Verhamme, A.; Orlitová, Ivana; Adamo, A.; Guaita, L.; Melinder, J.; Cannon, J.M.; Laursen, P.; Rivera-Thorsen, T.; Herenz, E.Ch.; Gruyters, P.; Mas-Hesse, J. M.; Kunth, D.; Sandberg, A.; Schaerer, D.; Mansson, J.-E.

    2016-01-01

    Roč. 587, March (2016), A77/1-A77/24 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GP14-20666P Institutional support: RVO:67985815 Keywords : galaxies * starburst * submillimeter Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  9. The effect of Lyman α self-absorption on population inversions between quantum states 2 and 3 of hydrogen-like ions in recombining plasmas

    International Nuclear Information System (INIS)

    Tallents, G.J.

    1978-01-01

    The effect in recombining plasmas of Lyman α self-absorption on quasi-steady-state population inversions between quantum states n = 2 and 3 of hydrogen-like ions is theoretically investigated. It is shown how the electron density range over which population inversion is possible diminishes as Lyman α self-absorption increases. The highest degree of absorption which can be tolerated and still achieve an inversion is shown to occur when the thermal limit corresponds to n approximately equal to 4. The results of the computations are related to the conditions to be found in the expansion plume of laser-produced plasmas. (author)

  10. PREDOMINANTLY LOW METALLICITIES MEASURED IN A STRATIFIED SAMPLE OF LYMAN LIMIT SYSTEMS AT Z  = 3.7

    Energy Technology Data Exchange (ETDEWEB)

    Glidden, Ana; Cooper, Thomas J.; Simcoe, Robert A. [Massachusetts Institute of Technology, 77 Massachusetts Ave, Cambridge, MA 02139 (United States); Cooksey, Kathy L. [Department of Physics and Astronomy, University of Hawai‘i at Hilo, 200 West Kāwili Street, Hilo, HI 96720 (United States); O’Meara, John M., E-mail: aglidden@mit.edu, E-mail: tjcooper@mit.edu, E-mail: simcoe@space.mit.edu, E-mail: kcooksey@hawaii.edu, E-mail: jomeara@smcvt.edu [Department of Physics, Saint Michael’s College, One Winooski Park, Colchester, VT 05439 (United States)

    2016-12-20

    We measured metallicities for 33 z = 3.4–4.2 absorption line systems drawn from a sample of H i-selected-Lyman limit systems (LLSs) identified in Sloan Digital Sky Survey (SDSS) quasar spectra and stratified based on metal line features. We obtained higher-resolution spectra with the Keck Echellette Spectrograph and Imager, selecting targets according to our stratification scheme in an effort to fully sample the LLS population metallicity distribution. We established a plausible range of H i column densities and measured column densities (or limits) for ions of carbon, silicon, and aluminum, finding ionization-corrected metallicities or upper limits. Interestingly, our ionization models were better constrained with enhanced α -to-aluminum abundances, with a median abundance ratio of [ α /Al] = 0.3. Measured metallicities were generally low, ranging from [M/H] = −3 to −1.68, with even lower metallicities likely for some systems with upper limits. Using survival statistics to incorporate limits, we constructed the cumulative distribution function (CDF) for LLS metallicities. Recent models of galaxy evolution propose that galaxies replenish their gas from the low-metallicity intergalactic medium (IGM) via high-density H i “flows” and eject enriched interstellar gas via outflows. Thus, there has been some expectation that LLSs at the peak of cosmic star formation ( z  ≈ 3) might have a bimodal metallicity distribution. We modeled our CDF as a mix of two Gaussian distributions, one reflecting the metallicity of the IGM and the other representative of the interstellar medium of star-forming galaxies. This bimodal distribution yielded a poor fit. A single Gaussian distribution better represented the sample with a low mean metallicity of [M/H] ≈ −2.5.

  11. Monte Carlo particle-trajectory models for neutral cometary gases. I. Models and equations. II. The spatial morphology of the Lyman-alpha coma

    International Nuclear Information System (INIS)

    Combi, M.R.; Smyth, W.H.

    1988-01-01

    The mathematical derivations of various methods employed in the Monte Carlo particle-trajectory model (MCPTM) are presented, and the application of the MCPTM to the calculation of the photochemical heating of the inner coma through the partial thermalization of cometary hydrogen atoms produced by the photodissociation of water is discussed. This model is then used to explain the observed morphology of the spatially extended Ly-alpha comas of comets. The rocket and Skylab images of the Ly-alpha coma of Comet Kohoutek are examined. 90 references

  12. The Canada-France deep fields survey-II: Lyman-break galaxies and galaxy clustering at z ~ 3

    Science.gov (United States)

    Foucaud, S.; McCracken, H. J.; Le Fèvre, O.; Arnouts, S.; Brodwin, M.; Lilly, S. J.; Crampton, D.; Mellier, Y.

    2003-10-01

    We present a large sample of z ~ 3 U-band dropout galaxies extracted from the Canada-France deep fields survey (CFDF). Our catalogue covers an effective area of ~ 1700 arcmin2 divided between three large, contiguous fields separated widely on the sky. To IAB=24.5, the survey contains 1294 Lyman-break candidates, in agreement with previous measurements by other authors, after appropriate incompleteness corrections have been applied to our data. Based on comparisons with spectroscopic observations and simulations, we estimate that our sample of Lyman-break galaxies is contaminated by stars and interlopers (lower-redshift galaxies) at no more than { ~ } 30%. We find that omega (theta ) is well fitted by a power-law of fixed slope, gamma =1.8, even at small (theta University of Hawaii, and at the Cerro Tololo Inter-American Observatory and Mayall 4-meter Telescopes, divisions of the National Optical Astronomy Observatories, which are operated by the Association of Universities for Research in Astronomy, Inc. under cooperative agreement with the National Science Foundation.

  13. A cosmic web filament revealed in Lyman-α emission around a luminous high-redshift quasar.

    Science.gov (United States)

    Cantalupo, Sebastiano; Arrigoni-Battaia, Fabrizio; Prochaska, J Xavier; Hennawi, Joseph F; Madau, Piero

    2014-02-06

    Simulations of structure formation in the Universe predict that galaxies are embedded in a 'cosmic web', where most baryons reside as rarefied and highly ionized gas. This material has been studied for decades in absorption against background sources, but the sparseness of these inherently one-dimensional probes preclude direct constraints on the three-dimensional morphology of the underlying web. Here we report observations of a cosmic web filament in Lyman-α emission, discovered during a survey for cosmic gas fluorescently illuminated by bright quasars at redshift z ≈ 2.3. With a linear projected size of approximately 460 physical kiloparsecs, the Lyman-α emission surrounding the radio-quiet quasar UM 287 extends well beyond the virial radius of any plausible associated dark-matter halo and therefore traces intergalactic gas. The estimated cold gas mass of the filament from the observed emission-about 10(12.0 ± 0.5)/C(1/2) solar masses, where C is the gas clumping factor-is more than ten times larger than what is typically found in cosmological simulations, suggesting that a population of intergalactic gas clumps with subkiloparsec sizes may be missing in current numerical models.

  14. The Ultraviolet Radiation Environment around M Dwarf Exoplanet Host Stars

    Science.gov (United States)

    France, Kevin; Froning, Cynthia S.; Linsky, Jeffrey L.; Roberge, Aki; Stocke, John T.; Tian, Feng; Bushinsky, Rachel; Desert, Jean-Michel; Mauas, Pablo; Mauas, Pablo; hide

    2013-01-01

    The spectral and temporal behavior of exoplanet host stars is a critical input to models of the chemistry and evolution of planetary atmospheres. Ultraviolet photons influence the atmospheric temperature profiles and production of potential biomarkers on Earth-like planets around these stars. At present, little observational or theoretical basis exists for understanding the ultraviolet spectra of M dwarfs, despite their critical importance to predicting and interpreting the spectra of potentially habitable planets as they are obtained in the coming decades. Using observations from the Hubble Space Telescope, we present a study of the UV radiation fields around nearby M dwarf planet hosts that covers both far-UV (FUV) and near-UV (NUV) wavelengths. The combined FUV+NUV spectra are publicly available in machine-readable format. We find that all six exoplanet host stars in our sample (GJ 581, GJ 876, GJ 436, GJ 832, GJ 667C, and GJ 1214) exhibit some level of chromospheric and transition region UV emission. No "UV-quiet" M dwarfs are observed. The bright stellar Lyman-alpha emission lines are reconstructed, and we find that the Lyman-alpha line fluxes comprise approximately 37%-75% of the total 1150-3100 A flux from most M dwarfs; approximately greater than 10(exp3) times the solar value. We develop an empirical scaling relation between Lyman-alpha and Mg II emission, to be used when interstellar H I attenuation precludes the direct observation of Lyman-alpha. The intrinsic unreddened flux ratio is F(Lyman-alpha)/F(Mg II) = 10(exp3). The F(FUV)/F(NUV) flux ratio, a driver for abiotic production of the suggested biomarkers O2 and O3, is shown to be approximately 0.5-3 for all M dwarfs in our sample, greather than 10(exp3) times the solar ratio. For the four stars with moderate signal-to-noise Cosmic Origins Spectrograph time-resolved spectra, we find UV emission line variability with amplitudes of 50%.500% on 10(exp2)-10(exp3) s timescales. This effect should be taken

  15. Alpha-Amylase Activity in Blood Increases after Pharmacological, But Not Psychological, Activation of the Adrenergic System.

    Directory of Open Access Journals (Sweden)

    Urs M Nater

    Full Text Available Alpha-amylase in both blood and saliva has been used as a diagnostic parameter. While studies examining alpha-amylase activity in saliva have shown that it is sensitive to physiological and psychological challenge of the adrenergic system, no challenge studies have attempted to elucidate the role of the adrenergic system in alpha-amylase activity in blood. We set out to examine the impact of psychological and pharmacological challenge on alpha-amylase in blood in two separate studies.In study 1, healthy subjects were examined in a placebo-controlled, double-blind paradigm using yohimbine, an alpha2-adrenergic antagonist. In study 2, subjects were examined in a standardized rest-controlled psychosocial stress protocol. Alpha-amylase activity in blood was repeatedly measured in both studies.Results of study 1 showed that alpha-amylase in blood is subject to stronger increases after injection of yohimbine compared to placebo. In study 2, results showed that there was no significant effect of psychological stress compared to rest.Alpha-amylase in blood increases after pharmacological activation of the adrenergic pathways suggesting that sympathetic receptors are responsible for these changes. Psychological stress, however, does not seem to have an impact on alpha-amylase in blood. Our findings provide insight into the mechanisms underlying activity changes in alpha-amylase in blood in healthy individuals.

  16. CLASP2: The Chromospheric LAyer Spectro-Polarimeter

    Science.gov (United States)

    Rachmeler, Laurel; E McKenzie, David; Ishikawa, Ryohko; Trujillo Bueno, Javier; Auchère, Frédéric; Kobayashi, Ken; Winebarger, Amy; Bethge, Christian; Kano, Ryouhei; Kubo, Masahito; Song, Donguk; Narukage, Noriyuki; Ishikawa, Shin-nosuke; De Pontieu, Bart; Carlsson, Mats; Yoshida, Masaki; Belluzzi, Luca; Stepan, Jiri; del Pino Alemná, Tanausú; Ballester, Ernest Alsina; Asensio Ramos, Andres

    2017-08-01

    We present the instrument, science case, and timeline of the CLASP2 sounding rocket mission. The successful CLASP (Chromospheric Lyman-Alpha Spectro-Polarimeter) sounding rocket flight in 2015 resulted in the first-ever linear polarization measurements of solar hydrogen Lyman-alpha line, which is sensitive to the Hanle effect and can be used to constrain the magnetic field and geometric complexity of the upper chromosphere. Ly-alpha is one of several upper chromospheric lines that contain magnetic information. In the spring of 2019, we will re-fly the modified CLASP telescope to measure the full Stokes profile of Mg II h & k near 280 nm. This set of lines is sensitive to the upper chromospheric magnetic field via both the Hanle and the Zeeman effects.

  17. Alpha-bungarotoxin binding to target cell in a developing visual system by carboxylated nanodiamond

    Energy Technology Data Exchange (ETDEWEB)

    Liu, K-K; Chen, P-Y; Lee, Tony J F; Chao, J-I [Institute of Pharmacology and Toxicology, Tzu Chi University, Hualien 970, Taiwan (China); Chen, M-F [Neuro-Medical Scientific Center, Tzu Chi General Hospital, Hualien 970, Taiwan (China); Cheng, C-L [Department of Physics, National Dong Hwa University, Hualien 974, Taiwan (China); Chang, C-C [Department of Biological Science and Technology, National Chiao Tung University, Hsin-Chu 300, Taiwan (China); Ho, Y-P [Department of Chemistry, National Dong Hwa University, Hualien 974, Taiwan (China)], E-mail: chaoji@mail.tcu.edu.tw

    2008-05-21

    system showing the binding of {alpha}-BTX to {alpha}7-nAChR.

  18. Calibration of sources for alpha spectroscopy systems

    International Nuclear Information System (INIS)

    Freitas, I.S.M.; Goncalez, O.L.

    1992-01-01

    This paper describes the calibration methodology for measuring the total alpha activity of plane and thin sources with the Alpha Spectrometer for Silicon Detector in the Nuclear Measures and Dosimetry laboratory at IEAv/CTA. (author)

  19. Integrated minicomputer alpha analysis system

    International Nuclear Information System (INIS)

    Vasilik, D.G.; Coy, D.E.; Seamons, M.; Henderson, R.W.; Romero, L.L.; Thomson, D.A.

    1978-01-01

    Approximately 1,000 stack and occupation air samples from plutonium and uranium facilities at LASL are analyzed daily. The concentrations of radio-nuclides in air are determined by measuring absolute alpha activities of particulates collected on air sample filter media. The Integrated Minicomputer Pulse system (IMPULSE) is an interface between many detectors of extremely simple design and a Digital Equipment Corporation (DEC) PDP-11/04 minicomputer. The detectors are photomultiplier tubes faced with zinc sulfide (ZnS). The average detector background is approximately 0.07 cpm. The IMPULSE system includes two mainframes, each of which can hold up to 64 detectors. The current hardware configuration includes 64 detectors in one mainframe and 40 detectors in the other. Each mainframe contains a minicomputer with 28K words of Random Access Memory. One minicomputer controls the detectors in both mainframes. A second computer was added for fail-safe redundancy and to support other laboratory computer requirements. The main minicomputer includes a dual floppy disk system and a dual DEC 'RK05' disk system for mass storage. The RK05 facilitates report generation and trend analysis. The IMPULSE hardware provides for passage of data from the detectors to the computer, and for passage of status and control information from the computer to the detector stations

  20. Monte Carlo alpha calculation

    Energy Technology Data Exchange (ETDEWEB)

    Brockway, D.; Soran, P.; Whalen, P.

    1985-01-01

    A Monte Carlo algorithm to efficiently calculate static alpha eigenvalues, N = ne/sup ..cap alpha..t/, for supercritical systems has been developed and tested. A direct Monte Carlo approach to calculating a static alpha is to simply follow the buildup in time of neutrons in a supercritical system and evaluate the logarithmic derivative of the neutron population with respect to time. This procedure is expensive, and the solution is very noisy and almost useless for a system near critical. The modified approach is to convert the time-dependent problem to a static ..cap alpha../sup -/eigenvalue problem and regress ..cap alpha.. on solutions of a/sup -/ k/sup -/eigenvalue problem. In practice, this procedure is much more efficient than the direct calculation, and produces much more accurate results. Because the Monte Carlo codes are intrinsically three-dimensional and use elaborate continuous-energy cross sections, this technique is now used as a standard for evaluating other calculational techniques in odd geometries or with group cross sections.

  1. Generation of ER{alpha}-floxed and knockout mice using the Cre/LoxP system

    Energy Technology Data Exchange (ETDEWEB)

    Antonson, P., E-mail: per.antonson@ki.se [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Omoto, Y.; Humire, P. [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Gustafsson, J.-A. [Department of Biosciences and Nutrition, Karolinska Institutet, Novum, SE-141 83 Huddinge (Sweden); Center for Nuclear Receptors and Cell Signaling, Department of Biology and Biochemistry, University of Houston, Houston, TX 77204 (United States)

    2012-08-10

    Highlights: Black-Right-Pointing-Pointer ER{alpha} floxed and knockout mice were generated. Black-Right-Pointing-Pointer Disruption of the ER{alpha} gene results in sterility in both male and female mice. Black-Right-Pointing-Pointer ER{alpha}{sup -/-} mice have ovaries with hemorrhagic follicles and hypoplastic uterus. Black-Right-Pointing-Pointer Female ER{alpha}{sup -/-} mice develop obesity. -- Abstract: Estrogen receptor alpha (ER{alpha}) is a nuclear receptor that regulates a range of physiological processes in response to estrogens. In order to study its biological role, we generated a floxed ER{alpha} mouse line that can be used to knock out ER{alpha} in selected tissues by using the Cre/LoxP system. In this study, we established a new ER{alpha} knockout mouse line by crossing the floxed ER{alpha} mice with Cre deleter mice. Here we show that genetic disruption of the ER{alpha} gene in all tissues results in sterility in both male and female mice. Histological examination of uterus and ovaries revealed a dramatically atrophic uterus and hemorrhagic cysts in the ovary. These results suggest that infertility in female mice is the result of functional defects of the reproductive tract. Moreover, female knockout mice are hyperglycemic, develop obesity and at the age of 4 months the body weight of these mice was more than 20% higher compared to wild type littermates and this difference increased over time. Our results demonstrate that ER{alpha} is necessary for reproductive tract development and has important functions as a regulator of metabolism in females.

  2. Acute moderate elevation of TNF-{alpha} does not affect systemic and skeletal muscle protein turnover in healthy humans

    DEFF Research Database (Denmark)

    Petersen, Anne Marie; Plomgaard, Peter; Fischer, Christian P

    2009-01-01

    -alpha infusion (rhTNF-alpha). We hypothesize that TNF-alpha increases human muscle protein breakdown and/or inhibit synthesis. Subjects and Methods: Using a randomized controlled, crossover design post-absorptive healthy young males (n=8) were studied 2 hours under basal conditions followed by 4 hours infusion...... with the phenylalanine 3-compartment model showed similar muscle synthesis, breakdown and net muscle degradation after 2 hours basal and after 4 hours Control or rhTNF-alpha infusion. Conclusion: This study is the first to show in humans that TNF-alpha does not affect systemic and skeletal muscle protein turnover, when......Context: Skeletal muscle wasting has been associated with elevations in circulating inflammatory cytokines, in particular TNF-alpha. Objective: In this study, we investigated whether TNF-alpha affects human systemic and skeletal muscle protein turnover, via a 4 hours recombinant human TNF...

  3. Air alpha monitoring device and system for the calibration of the track detectors

    International Nuclear Information System (INIS)

    Danis, A; Oncescu, M.; Ciubotariu, M.

    2001-01-01

    The radon measurement plays a critical role: - in monitoring the human health and safety, due to radon destructive health effects. Sustained exposures of humans to high concentration of radon, in fact to high concentrations of its decay products, can produce lung cancer; - in a variety of geophysical, geochemical, hydrological and atmospheric investigations, such as exploring resources of uranium or hydrocarbons. The transport of radon within the earth, waters and atmosphere makes it a useful tracer in these purposes. in both cases, the reliable long-term measurements are required because usual short-term variations in concentration need to be averaged. These variations are caused by factors such as relative humidity, temperature, atmospheric pressure and their seasonal variations, moisture content in the air, or ventilation in the dwelling or working places. The integrating measurement methods meet these requirements. Among them, the alpha track method is one of the adequate and useful method and it is used by authors in radon measurements in dwelling and working places including mines and house cellars. The best etched track alpha detector for radon measurements proved to be the detector CR-39 due to: - its sensitivity to alpha particles emitted by radon decay products; - its stability against various environmental factors; - its high degree of optical clarity, was used in a proper device for alpha monitoring in air. Its calibration for radon measurements was performed in the proper calibration system. The general descriptions and specifications were given previously. Only some characteristics of these devices are given here. For air alpha monitoring device: i) equipped with filter, during alpha exposure, the alpha particles of radon are registered in the etched track detector mounted inside (ρ Rn - track density); ii) without filter, the alpha particles emitted by radon + its alpha decay products/their aerosols are registered in the detector (ρ tot - track

  4. Deficiency of a alpha-1-antitrypsin influences systemic iron homeostasis

    Science.gov (United States)

    Abstract Background: There is evidence that proteases and anti-proteases participate in the iron homeostasis of cells and living systems. We tested the postulate that alpha-1 antitrypsin (A1AT) polymorphism and the consequent deficiency of this anti-protease in humans are asso...

  5. Overproduction of alpha chains provides a proton-insensitive component to the bluefish hemoglobin system.

    Science.gov (United States)

    Bonaventura, Celia; Godette, Gerald; Stevens, Robert; Brenowitz, Michael; Henkens, Robert

    2005-12-09

    Expression of alpha and beta chains and their post-translational assembly into alpha(2)beta(2) tetramers is fundamental to the formation and function of most vertebrate hemoglobins. There is a strong evolutionary bias that favors expression of equal amounts of the two types of chains, because cooperativity, pH sensitivity, and anionic control of function occurs only for the alpha(2)beta(2) tetramers. Remarkably, an over-production of alpha chains, as in the pathological condition known as beta thalassemia in humans, is adaptive rather than pathological in the bluefish hemoglobin system. The thalassemia of the bluefish is a novel means of providing for oxygen uptake and delivery when low pH conditions incapacitate the highly pH-sensitive Root effect hemoglobins of the fish. Although fish often have pH-insensitive along with highly pH-sensitive hemoglobins, having pH-insensitive alpha chain monomers in circulation is an unusual structural variation. The role of bluefish alpha chains in oxygen transport is enabled by their remarkably lower oxygen affinity relative to human alpha chains. This is the first reported case of a thalassemic condition that is maintained in a species as an adaptive advantage.

  6. Hypothalamic PGC-1 alpha Protects Against High-Fat Diet Exposure by Regulating ER alpha

    NARCIS (Netherlands)

    Morselli, Eugenia; Fuente-Martin, Esther; Finan, Brian; Kim, Min; Frank, Aaron; Garcia-Caceres, Cristina; Navas, Carlos Rodriguez; Gordillo, Ruth; Neinast, Michael; Kalainayakan, Sarada P.; Li, Dan L.; Gao, Yuanqing; Yi, Chun-Xia; Hahner, Lisa; Palmer, Biff F.; Tschöp, Matthias H.; Clegg, Deborah J.

    2014-01-01

    High-fat diets (HFDs) lead to obesity and inflammation in the central nervous system (CNS). Estrogens and estrogen receptor alpha (ER alpha) protect premenopausal females from the metabolic complications of inflammation and obesity-related disease. Here, we demonstrate that hypothalamic PGC-1 alpha

  7. Fluctuations in radiation backgrounds at high redshift and the first stars

    Science.gov (United States)

    Holzbauer, Lauren Nicole

    The first stars to light up our universe are as yet unseen, but there have been many attempts to elucidate their properties. The characteristics of these stars (`Population/Pop III' stars) that we do know lie mostly within theory; they formed out of metal-free hydrogen and helium gas contained in dark matter minihalos at redshifts z 20-30. The extent to which Pop III star formation reached into later times is unknown. Current and near future instruments are incapable of resolving individual Pop III stars. Consequently, astronomers must devise creative means with which to indirectly predict and measure and their properties. In this thesis, we will investigate a few of those means. We use a new method to model fluctuations of the Lyman-Werner (LW) and Lyman-alpha radiation backgrounds at high redshift. At these early epochs the backgrounds are symptoms of a universe newly lit with its first stars. LW photons (11.5-13.6 eV) are of particular interest because they dissociate molecular hydrogen, the primary coolant in the first minihalos that is necessary for star formation. By using a variation of the `halo model', which describes the spatial distribution and clustering of halos, we can efficiently generate power spectra for these backgrounds. Spatial fluctuations in the LW and (indirectly) the Lyman-alpha BG can tell us about the transition from primordial star formation to a more metal-enriched mode that marks the beginning of the second generation of stars in our Universe. The Near Infrared Background (NIRB) has for some time been considered a potential tool with which to indirectly observe the first stars. Ultraviolet (UV) emission from these stars is redshifted into the NIR band, making the NIRB amenable for hunting Pop III stellar signatures. There have been several measurements of the NIRB and subsequent theoretical studies attempting to explain them in recent years. Though controversial, residual levels of the mean NIRB intensity and anisotropies have been

  8. PGC-1alpha Deficiency Causes Multi-System Energy Metabolic Derangements: Muscle Dysfunction, Abnormal Weight Control and Hepatic Steatosis

    Directory of Open Access Journals (Sweden)

    Leone Teresa C

    2005-01-01

    Full Text Available The gene encoding the transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha was targeted in mice. PGC-1alpha null (PGC-1alpha-/- mice were viable. However, extensive phenotyping revealed multi-system abnormalities indicative of an abnormal energy metabolic phenotype. The postnatal growth of heart and slow-twitch skeletal muscle, organs with high mitochondrial energy demands, is blunted in PGC-1alpha-/- mice. With age, the PGC-1alpha-/- mice develop abnormally increased body fat, a phenotype that is more severe in females. Mitochondrial number and respiratory capacity is diminished in slow-twitch skeletal muscle of PGC-1alpha-/- mice, leading to reduced muscle performance and exercise capacity. PGC-1alpha-/- mice exhibit a modest diminution in cardiac function related largely to abnormal control of heart rate. The PGC-1alpha-/- mice were unable to maintain core body temperature following exposure to cold, consistent with an altered thermogenic response. Following short-term starvation, PGC-1alpha-/- mice develop hepatic steatosis due to a combination of reduced mitochondrial respiratory capacity and an increased expression of lipogenic genes. Surprisingly, PGC-1alpha-/- mice were less susceptible to diet-induced insulin resistance than wild-type controls. Lastly, vacuolar lesions were detected in the central nervous system of PGC-1alpha-/- mice. These results demonstrate that PGC-1alpha is necessary for appropriate adaptation to the metabolic and physiologic stressors of postnatal life.

  9. PGC-1alpha deficiency causes multi-system energy metabolic derangements: muscle dysfunction, abnormal weight control and hepatic steatosis.

    Directory of Open Access Journals (Sweden)

    Teresa C Leone

    2005-04-01

    Full Text Available The gene encoding the transcriptional coactivator peroxisome proliferator-activated receptor-gamma coactivator-1alpha (PGC-1alpha was targeted in mice. PGC-1alpha null (PGC-1alpha(-/- mice were viable. However, extensive phenotyping revealed multi-system abnormalities indicative of an abnormal energy metabolic phenotype. The postnatal growth of heart and slow-twitch skeletal muscle, organs with high mitochondrial energy demands, is blunted in PGC-1alpha(-/- mice. With age, the PGC-1alpha(-/- mice develop abnormally increased body fat, a phenotype that is more severe in females. Mitochondrial number and respiratory capacity is diminished in slow-twitch skeletal muscle of PGC-1alpha(-/- mice, leading to reduced muscle performance and exercise capacity. PGC-1alpha(-/- mice exhibit a modest diminution in cardiac function related largely to abnormal control of heart rate. The PGC-1alpha(-/- mice were unable to maintain core body temperature following exposure to cold, consistent with an altered thermogenic response. Following short-term starvation, PGC-1alpha(-/- mice develop hepatic steatosis due to a combination of reduced mitochondrial respiratory capacity and an increased expression of lipogenic genes. Surprisingly, PGC-1alpha(-/- mice were less susceptible to diet-induced insulin resistance than wild-type controls. Lastly, vacuolar lesions were detected in the central nervous system of PGC-1alpha(-/- mice. These results demonstrate that PGC-1alpha is necessary for appropriate adaptation to the metabolic and physiologic stressors of postnatal life.

  10. Scattered light characterization of FORTIS

    Science.gov (United States)

    McCandliss, Stephan R.; Carter, Anna; Redwine, Keith; Teste, Stephane; Pelton, Russell; Hagopian, John; Kutyrev, Alexander; Li, Mary J.; Moseley, S. Harvey

    2017-08-01

    We describe our efforts to build a Wide-Field Lyman alpha Geocoronal simulator (WFLaGs) for characterizing the end-to-end sensitivity of FORTIS (Far-UV Off Rowland-circle Telescope for Imaging and Spectroscopy) to scattered Lyman α emission from outside of the nominal (1/2 degree)2 field-of-view. WFLaGs is a 50 mm diameter F/1 aluminum parabolic collimator fed by a hollow cathode discharge lamp with a 80 mm clear MgF2 window housed in a vacuum skin. It creates emission over a 10 degree FOV. WFLaGS will allow us to validate and refine a recently developed scattered light model and verify our scatter light mitigation strategies, which will incorporate low scatter baffle materials, and possibly 3-d printed light traps, covering exposed scatter centers. We present measurements of scattering intensity of Lyman alpha as a function of angle with respect to the specular reflectance direction for several candidate baffle materials. Initial testing of WFLaGs will be described.

  11. Radon Daughters Background Reduction in Alpha Particles Counting System

    International Nuclear Information System (INIS)

    Dadon, S. S.; Pelled, O.; Orion, I.

    2014-01-01

    The ABPC method is using a serially occurring events of the beta decay of the 214Bi fallow by alpha decay of the 214Po that take place almost simultaneously to detect the Pseudo Coincidence Event (PCE) from the RDP, and to subtract them from the gross alpha counts. 267 This work showed that it is possible to improve the efficiency of RDP background reduction, including subtracting the 218Po contribution by using the ABPC method based on a single solid state silicon PIPS detector. False counts percentage obtained at the output of the PCE circuit were smaller than 0.1%. The results show that the PCE circuit was not influenced by non RDP alpha emitters. The PCE system did not reduce the non PCE of the 218Po. After 20 minutes the 218Po was strongly decayed, and its contribution became negligible. In order to overcome this disadvantage, a mathematical matching calculations for the 214Po and the 218Po decay equations were employed, and a constant ratio of the APo214(0) / APo218(0) was obtained. This ratio can be used to estimate the count rate of the 218Po at the first 20 minutes, and to subtract it from the total count rate in order to obtain correct RDP reduction

  12. The grand partition function Z ({alpha},{beta}) of a quantum system is studied, using diagrammatic representations of the perturbation expansion; La grande fonction de partition Z ({alpha},{beta}) d'un systeme quantique est etudies en utilisant des representations diagrammatiques du developpement en serie des perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Dominicis, C de [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    The grand partition function Z ({alpha},{beta}) of a quantum system is studied, using diagrammatic representations of the perturbation expansion. For a fermions system, it is possible to show, by proper resummation, without approximations but under some 'regularity hypothesis', that Log Z ({alpha},{beta}) takes a form where, besides trivial dependences, {alpha} and {beta} only appear through a statistical factor F{sub k}{sup -} = [1 + e{sup -{alpha}}{sup +{beta}}{sup {epsilon}{sub k}{sup 0}}{sup -{beta}}{sup W{sub k}}]{sup -1}. W{sub k} is a (real) self-consistent potential, generalized to all orders and can be defined by a stationary condition on Log Z ({alpha},{beta}) under variations of F{sub k}{sup -}. The thermodynamical quantities take a form analogous to the expressions Landau introduced for the Fermi liquids. The zero temperature limit (for isotropic systems) gives back Goldstone expressions for the ground state of a system. (author) [French] La grande fonction de partition Z ({alpha},{beta}) d'un systeme quantique est etudiee en utilisant des representations diagrammatiques du developpement en serie des perturbations. Pour un systeme de fermions on peut, par des resommations adequates, sans approximations mais sous reserve d'une 'hypothese de regularite', mettre Log Z ({alpha},{beta}) sous une forme ou, en dehors de dependances triviales, {alpha} et {beta} n'interviennent que par l'intermediaire d'un facteur statistique F{sub k}{sup -} = [1 + e{sup -{alpha}}{sup +{beta}}{sup {epsilon}{sub k}{sup 0}}{sup -{beta}}{sup W{sub k}}]{sup -1}. W{sub k} est ici un potentiel self-consistant (reel) generalise a tous les ordres et peut etre defini par une condition de stationnarite de Log Z ({alpha},{beta}) pour des variations de F{sub k}{sup -}. Les grandeurs thermodynamiques prennent une forme analogue aux expressions que LANDAU a introduites pour les liquides de FERMI. A la limite de la temperature nulle (et pour un systeme isotrope) on retrouve terme a terme les

  13. Exploring the Structure of the Distant Universe with MUSE Data Cubes

    Science.gov (United States)

    MacDougall, Mason; Christensen, Lise

    2018-01-01

    The mass distribution in intergalactic and circumgalactic space is not well known since it is difficult to characterize objects in the distant universe. An ideal tool for studying such distant structure is the Multi-Unit Spectroscopic Explorer (MUSE) of the Very Large Telescope array, which employs a wide field-of-view and a large spectral range to produce high spatial resolution datasets. Here we exploit the 2 spatial dimensions and 1 spectral dimension of a particular MUSE “data cube” to identify and characterize emission line sources near the line-of-sight to quasar PKS1937-101, which lies at a redshift of z=3.787. In particular, we search for galaxy companions to a z=3.572 Lyman-limit system measured in the quasar spectrum and find an associated Lyman-alpha emitter at z=3.556 with a projected distance of 30.2 kpc from the quasar line-of-sight. Through a combination of automated source extraction and manual investigation, we also identify 25 emission line galaxies and 1 other Lyman-alpha emitter in our field. The proximity of several of these objects to the quasar line-of-sight allows us to reliably identify absorption lines in the quasar spectrum that can be associated with observed emission lines with resolved fluxes. This will help characterize the metallicities and kinematics of galaxy halos and circumgalactic media in the early universe.

  14. Real time alpha value measurement with Feynman-α method utilizing time series data acquisition on low enriched uranium system

    International Nuclear Information System (INIS)

    Tonoike, Kotaro; Yamamoto, Toshihiro; Watanabe, Shoichi; Miyoshi, Yoshinori

    2003-01-01

    As a part of the development of a subcriticality monitoring system, a system which has a time series data acquisition function of detector signals and a real time evaluation function of alpha value with the Feynman-alpha method was established, with which the kinetic parameter (alpha value) was measured at the STACY heterogeneous core. The Hashimoto's difference filter was implemented in the system, which enables the measurement at a critical condition. The measurement result of the new system agreed with the pulsed neutron method. (author)

  15. Antagonizing the alpha(4)beta(1) Integrin, but Not alpha(4)beta(7), Inhibits Leukocytic Infiltration of the Central Nervous System in Rhesus Monkey Experimental Autoimmune Encephalomyelitis

    NARCIS (Netherlands)

    Haanstra, Krista G.; Hofman, Sam O.; Estevao, Dave M. Lopes; Blezer, Erwin L. A.; Bauer, Jan; Yang, Li-Li; Wyant, Tim; Csizmadia, Vilmos; 't Hart, Bert A.; Fedyk, Eric R.

    2013-01-01

    The immune system is characterized by the preferential migration of lymphocytes through specific tissues (i.e., tissue tropism). Tissue tropism is mediated, in part, by the alpha(4) integrins expressed by T lymphocytes. The alpha(4)beta(1) integrin mediates migration of memory T lymphocytes into the

  16. The first continuous coherent Lyman-alpha source

    NARCIS (Netherlands)

    Walz, J.; Pahl, A.; Eikema, K.S.E.; Hansch, T.W.

    2001-01-01

    Ultrahigh-resolution laser spectroscopy of antihydrogen atoms in a magnetic trap could open a new field of challenging tests of the fundamental CPT theorem. The required laser cooling and laser spectroscopy techniques are also essential for future experiments on the gravitational acceleration of

  17. Prediction of radiation-induced liver disease by Lyman normal-tissue complication probability model in three-dimensional conformal radiation therapy for primary liver carcinoma

    International Nuclear Information System (INIS)

    Xu ZhiYong; Liang Shixiong; Zhu Ji; Zhu Xiaodong; Zhao Jiandong; Lu Haijie; Yang Yunli; Chen Long; Wang Anyu; Fu Xiaolong; Jiang Guoliang

    2006-01-01

    Purpose: To describe the probability of RILD by application of the Lyman-Kutcher-Burman normal-tissue complication (NTCP) model for primary liver carcinoma (PLC) treated with hypofractionated three-dimensional conformal radiotherapy (3D-CRT). Methods and Materials: A total of 109 PLC patients treated by 3D-CRT were followed for RILD. Of these patients, 93 were in liver cirrhosis of Child-Pugh Grade A, and 16 were in Child-Pugh Grade B. The Michigan NTCP model was used to predict the probability of RILD, and then the modified Lyman NTCP model was generated for Child-Pugh A and Child-Pugh B patients by maximum-likelihood analysis. Results: Of all patients, 17 developed RILD in which 8 were of Child-Pugh Grade A, and 9 were of Child-Pugh Grade B. The prediction of RILD by the Michigan model was underestimated for PLC patients. The modified n, m, TD 5 (1) were 1.1, 0.28, and 40.5 Gy and 0.7, 0.43, and 23 Gy for patients with Child-Pugh A and B, respectively, which yielded better estimations of RILD probability. The hepatic tolerable doses (TD 5 ) would be MDTNL of 21 Gy and 6 Gy, respectively, for Child-Pugh A and B patients. Conclusions: The Michigan model was probably not fit to predict RILD in PLC patients. A modified Lyman NTCP model for RILD was recommended

  18. The tree-alpha Faddeev calculation on 12C bound states with a Pauli correct alpha-alpha potential

    International Nuclear Information System (INIS)

    Kamada, Hiroyuki; Oryu, Shinsho

    1986-01-01

    The three-alpha model of 12 C is investigated by the Faddeev formalism with the UIM alpha-alpha potential, in which the Pauli effect between two-alpha system was taken into account adequately. The potential can reproduce the on- and off-shell effects of the alpha-alpha interaction by the rank-4 separable type for the S-wave, the rank-3 one for the D-wave, and the rank-2 one for the G-wave, in which two of the ranks in the S-wave, and one in the D-wave are prepared to eliminate the Pauli forbidden states. We obtained three even states J π = 0 + , 2 + , 4 + , and two odd states 1 - , 3 - , below the alpha- 8 Be(0 + g.s) threshold energy. The even parity states gain larger binding energies than those which have been obtained by former Faddeev calculation with the rank-1 Kukulin and Neudatchin (KN) potential. On the other hand, for the odd parity states, we obtained smaller binding energies than the former one. It is found that our Faddeev calculation with the UIM potential does not miss any important low-lying levels of 12 C, in which any spurious states do not appear. (author)

  19. New miniaturized alpha/beta spectrometric system for the surface contamination monitoring and radon personal dosimeter

    International Nuclear Information System (INIS)

    Streil, T.; Oeser, V.; Holfeld, G.

    1998-01-01

    The heart of the new miniaturized alpha/beta spectroscopic system is a Smart Card MCA having a 12 bit resolution and a 32 bit memory for each channel with the size of a cheque card. The system consists of a single or up to 12 alpha spectrometers in a battery powered casing with connectors for direct detector/amplifier module plugging. Surface contamination in the order of 1 Bq/cm 2 of 239 Pu can be measured. (M.D.)

  20. A Method Validation for Determination of Gross Alpha and Gross Beta in Water Sample Using Low Background Gross Alpha/ Beta Counting System

    International Nuclear Information System (INIS)

    Zal Uyun Wan Mahmood; Norfaizal Mohamed; Nita Salina Abu Bakar

    2016-01-01

    Method validation (MV) for the measurement of gross alpha and gross beta activity in water (drinking, mineral and environmental) samples using Low Background Gross Alpha/ Beta Counting System was performed to characterize precision, accuracy and reliable results. The main objective of this assignment is to ensure that both the instrument and method always good performed and resulting accuracy and reliable results. Generally, almost the results of estimated RSD, z-score and U_s_c_o_r_e were reliable which are recorded as ≤30 %, less than 2 and less than 1.5, respectively. Minimum Detected Activity (MDA) was estimated based on the counting time of 100 minutes and present background counting value of gross alpha (0.01 - 0.35 cpm) and gross beta (0.50 - 2.18 cpm). Estimated Detection Limit (DL) was 0.1 Bq/ L for gross alpha and 0.2 Bq/ L for gross beta and expended uncertainty was relatively small of 9.77 % for gross alpha and 10.57 % for gross beta. Align with that, background counting for gross alpha and gross beta was ranged of 0.01 - 0.35 cpm and 0.50 - 2.18 cpm, respectively. While, sample volume was set at minimum of 500 mL and maximum of 2000 mL. These proven the accuracy and precision result that are generated from developed method/ technique is satisfactory and method is recommended to be used. Therefore, it can be concluded that the MV found no doubtful on the ability of the developed method. The test result showed the method is suitable for all types of water samples which are contained several radionuclides and elements as well as any impurities that interfere the measurement analysis of gross alpha and gross beta. (author)

  1. Radial-velocity variations in Alpha Ori, Alpha Sco, and Alpha Her

    International Nuclear Information System (INIS)

    Smith, M.A.; Patten, B.M.; Goldberg, L.

    1989-01-01

    Radial-velocity observations of Alpha Ori, Alpha Sco A, and Alpha Her A are used to study radial-velocity periodicities in M supergiants. The data refer to several metallic lines in the H-alpha region and to H-alpha itself. It is shown that Alpha Ori and Alpha Sco A have cycle lengths of about 1 yr and semiamplitudes of 2 km/s. It is suggested that many semiregular red supergiant varibles such as Alpha Ori may be heading toward chaos. All three stars show short-term stochastic flucutations with an amplitude of 1-2 km/s. It is found that the long-term variability of H-alpha velocities may be a consequence of intermittent failed ejections. 58 refs

  2. A Faraday rotation search for magnetic fields in quasar damped Ly alpha absorption systems

    Science.gov (United States)

    Oren, Abraham L.; Wolfe, Arthur M.

    1995-01-01

    We present the results of a Faraday rotation survey of 61 radio-bright QSOs conducted at the National Radio Astronomy Observatory (NRAO) Very Large Array (VLA). The Galactic contribution to the Faraday rotation is estimated and subtracted to determine the extragalactic rotation measure (RRM) for each source. Eleven of these QSOs are known to exhibit damped Ly alpha absorption. The rate of incidence of significant Faraday rotation of these 11 sources is compared to the remaining 50 and is found to be higher at the 99.8% confidence level. However, as this is based upon only two detections of Faraday rotation in the damped Ly alpha sample, the result is only tentative. If the two detections in the damped Ly alpha sample are dug to the absorbing systems, then the inferred rotation measure induced by these systems is roughly 250 rad/sq m. The two detections were for the two lowest redshift absorbers in the sample. We find that a rotation measure of 250 rad/sq m would have gone undetected for any other absorber in the damped Ly alpha sample due to the 1/(1 + 2) squared dilution of the observed RRM with redshift. Thus the data are consistent with, but do not prove, the hypothesis that Faraday rotation is a generic property of damped Ly alpha absorbers. We do not confirm the suggestion that the amplitude of RRMs increases with redshift. Rather, the data are consistent with no redshift evolution. We find that the uncertainty in the estimation of the Galactic rotation measure (GRM) is a more serious problem than previously realized for extra-galactic Faraday rotation studies of QSO absorbers. A careful analysis of current methods for estimating GRM indicate that it can be determined to an accuracy of about 15 - 20 rad/sq m. Previous studies underestimated this uncertainty by more than a factor of 2. Due to this uncertainty, rotation measures such as we suspect are associated with damped Ly alpha absorption systems can only be detected at redshifts less than z approximately

  3. ALPHA/PHOENIX-P/ANC system validation for Angra-1 neutronic calculations

    International Nuclear Information System (INIS)

    Ponzoni Filho, Pedro; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso; Fernandes, Vanderlei Borba; Fetterman, R.J.

    1995-01-01

    The ALPHA/PHOENIX-P/ANC (APA) code package is an advanced neutronic calculation system for pressurized water reactor (PWR). PHOENIX-P generates the required cross sections for the fuel, burnable absorbers, control rods and baffle/reflector region. The ALPHA code is used to automate the generation of these cross-sections as well as process the PHOENIX-P results to generate the ANC model input. ANC is a three dimensional advanced nodal code used for the modeling of the, depletion of the fuel in the core, and for the calculation of power distributions, rod worths and other reactivity parameters. This paper provides brief overview of the APA methodology for reload core design of Angra Unit 1 Cycles 1 and 2. Results included are predicted power distributions, control rod worths and other reactivity parameters compared to plant measurements. These results demonstrate that the APA system can be used for the reload core design. (author). 7 refs, 9 figs

  4. ALPHA/PHOENIX-P/ANC system validation for Angra-1 neutronic calculations

    Energy Technology Data Exchange (ETDEWEB)

    Ponzoni Filho, Pedro; Sato, Sadakatu; Santos, Teresinha Ipojuca Cardoso; Fernandes, Vanderlei Borba [FURNAS, Rio de Janeiro, RJ (Brazil); Fetterman, R.J. [Westinghouse Electric Corp., Pittsburgh, PA (United States)

    1995-12-31

    The ALPHA/PHOENIX-P/ANC (APA) code package is an advanced neutronic calculation system for pressurized water reactor (PWR). PHOENIX-P generates the required cross sections for the fuel, burnable absorbers, control rods and baffle/reflector region. The ALPHA code is used to automate the generation of these cross-sections as well as process the PHOENIX-P results to generate the ANC model input. ANC is a three dimensional advanced nodal code used for the modeling of the, depletion of the fuel in the core, and for the calculation of power distributions, rod worths and other reactivity parameters. This paper provides brief overview of the APA methodology for reload core design of Angra Unit 1 Cycles 1 and 2. Results included are predicted power distributions, control rod worths and other reactivity parameters compared to plant measurements. These results demonstrate that the APA system can be used for the reload core design. (author). 7 refs, 9 figs.

  5. The Lyman alpha reference sample VII. Spatially resolved H alpha kinematics

    Czech Academy of Sciences Publication Activity Database

    Herenz, E.Ch.; Gruyters, P.; Orlitová, Ivana; Hayes, M.; Ostlin, G.; Cannon, J.M.; Roth, M.M.; Bik, A.; Pardy, S.; Oti-Floranes, H.; Mas-Hesse, J. M.; Adamo, A.; Atek, H.; Duval, F.; Guaita, L.; Kunth, D.; Laursen, P.; Melinder, J.; Puschnig, J.; Rivera-Thorsen, T.; Schaerer, D.; Verhamme, A.

    2016-01-01

    Roč. 587, March (2016), A78/1-A78/27 ISSN 0004-6361 R&D Projects: GA ČR(CZ) GP14-20666P Institutional support: RVO:67985815 Keywords : galaxies * ISM * starburst Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 4.378, year: 2014

  6. The grand partition function Z ({alpha},{beta}) of a quantum system is studied, using diagrammatic representations of the perturbation expansion; La grande fonction de partition Z ({alpha},{beta}) d'un systeme quantique est etudies en utilisant des representations diagrammatiques du developpement en serie des perturbations

    Energy Technology Data Exchange (ETDEWEB)

    Dominicis, C. de [Commissariat a l' Energie Atomique, Saclay (France).Centre d' Etudes Nucleaires

    1961-07-01

    The grand partition function Z ({alpha},{beta}) of a quantum system is studied, using diagrammatic representations of the perturbation expansion. For a fermions system, it is possible to show, by proper resummation, without approximations but under some 'regularity hypothesis', that Log Z ({alpha},{beta}) takes a form where, besides trivial dependences, {alpha} and {beta} only appear through a statistical factor F{sub k}{sup -} = [1 + e{sup -{alpha}}{sup +{beta}}{sup {epsilon}{sub k}{sup 0}}{sup -{beta}}{sup W{sub k}}]{sup -1}. W{sub k} is a (real) self-consistent potential, generalized to all orders and can be defined by a stationary condition on Log Z ({alpha},{beta}) under variations of F{sub k}{sup -}. The thermodynamical quantities take a form analogous to the expressions Landau introduced for the Fermi liquids. The zero temperature limit (for isotropic systems) gives back Goldstone expressions for the ground state of a system. (author) [French] La grande fonction de partition Z ({alpha},{beta}) d'un systeme quantique est etudiee en utilisant des representations diagrammatiques du developpement en serie des perturbations. Pour un systeme de fermions on peut, par des resommations adequates, sans approximations mais sous reserve d'une 'hypothese de regularite', mettre Log Z ({alpha},{beta}) sous une forme ou, en dehors de dependances triviales, {alpha} et {beta} n'interviennent que par l'intermediaire d'un facteur statistique F{sub k}{sup -} = [1 + e{sup -{alpha}}{sup +{beta}}{sup {epsilon}{sub k}{sup 0}}{sup -{beta}}{sup W{sub k}}]{sup -1}. W{sub k} est ici un potentiel self-consistant (reel) generalise a tous les ordres et peut etre defini par une condition de stationnarite de Log Z ({alpha},{beta}) pour des variations de F{sub k}{sup -}. Les grandeurs thermodynamiques prennent une forme analogue aux expressions que LANDAU a introduites pour les liquides de FERMI. A la limite de la temperature nulle (et pour un

  7. Design and construction of a system for determining Radon-222 through Alpha spectroscopy

    International Nuclear Information System (INIS)

    Bonifacio, J.; Iturbe, J.L.

    1992-02-01

    The study of the present work consists on designing a system to measure gas 222 Rn, using a surface barrier detector, in order to obtaining a more accuracy measure of this isotope by means of an alpha particle spectra and thus to try to avoid the influence of the radioactivity of the isotope descendants of short half life, which are also emitting of alpha particles, since by other methods its should make a series of corrections to obtain the real value of the radon activity. (Author)

  8. Theory of Feynman-alpha technique with masking window for accelerator-driven systems

    International Nuclear Information System (INIS)

    Kitamura, Yasunori; Misawa, Tsuyoshi

    2017-01-01

    Highlights: • A theory of the modified Feynman-alpha technique for the ADS was developed. • The experimental conditions under which this technique works were discussed. • It is expected this technique is applied to the subcriticality monitor for the ADS. - Abstract: Recently, a modified Feynman-alpha technique for the subcritical system driven by periodically triggered neutron bursts was developed. One of the main features of this technique is utilization of a simple formula that is advantageous in evaluating the subcriticality. However, owing to the absence of the theory of this technique, this feature has not been fully investigated yet. In the present study, a theory of this technique is provided. Furthermore, the experimental conditions under which the simple formula works are discussed to apply this technique to the subcriticality monitor for the accelerator-driven system.

  9. Lyman Break Analogs: Constraints on the Formation of Extreme Starbursts at Low and High Redshift

    Science.gov (United States)

    Goncalves, Thiago S.; Overzier, Roderik; Basu-Zych, Antara; Martin, D. Christopher

    2011-01-01

    Lyman Break Analogs (LBAs), characterized by high far-UV luminosities and surface brightnesses as detected by GALEX, are intensely star-forming galaxies in the low-redshift universe (z approximately equal to 0.2), with star formation rates reaching up to 50 times that of the Milky Way. These objects present metallicities, morphologies and other physical properties similar to higher redshift Lyman Break Galaxies (LBGs), motivating the detailed study of LBAs as local laboratories of this high-redshift galaxy population. We present results from our recent integral-field spectroscopy survey of LBAs with Keck/OSIRIS, which shows that these galaxies have the same nebular gas kinematic properties as high-redshift LBGs. We argue that such kinematic studies alone are not an appropriate diagnostic to rule out merger events as the trigger for the observed starburst. Comparison between the kinematic analysis and morphological indices from HST imaging illustrates the difficulties of properly identifying (minor or major) merger events, with no clear correlation between the results using either of the two methods. Artificial redshifting of our data indicates that this problem becomes even worse at high redshift due to surface brightness dimming and resolution loss. Whether mergers could generate the observed kinematic properties is strongly dependent on gas fractions in these galaxies. We present preliminary results of a CARMA survey for LBAs and discuss the implications of the inferred molecular gas masses for formation models.

  10. Immunostimulatory effects of natural human interferon-alpha (huIFN-alpha) on carps Cyprinus carpio L.

    Science.gov (United States)

    Watanuki, Hironobu; Chakraborty, Gunimala; Korenaga, Hiroki; Kono, Tomoya; Shivappa, R B; Sakai, Masahiro

    2009-10-15

    Human interferon-alpha (huIFN-alpha) is an important immunomodulatory substance used in the treatment and prevention of numerous infectious and immune-related diseases in animals. However, the immunostimulatory effects of huIFN-alpha in fish remain to be investigated. In the current study, the immune responses of the carp species Cyprinus carpio L. to treatment with huIFN-alpha were analyzed via measurement of superoxide anion production, phagocytic activity and the expression of cytokine genes including interleukin-1beta, tumor necrosis factor-alpha and interleukin 10. Low doses of huIFN-alpha were administered orally once a day for 3 days, and sampling was carried out at 1, 3 and 5 days post-treatment. Our results indicate that a low dose of huIFN-alpha significantly increased phagocytic activity and superoxide anion production in the carp kidney. The huIFN-alpha-treated fish also displayed a significant upregulation in cytokine gene expression. The current study demonstrates the stimulatory effects of huIFN-alpha on the carp immune system and highlights the immunomodulatory role of huIFN-alpha in fish.

  11. Design and construction of a system to analyze Radon 222 by means of alpha spectroscopy

    International Nuclear Information System (INIS)

    Martinez, J.B.

    1991-01-01

    Design and construction of a system to measure gaseous Radon 222 which arise from a source of Radium 226 electrodeposited in a stainless disc is described. Such a system allows to differentiate the energies of radium where they come from, as well as energies of daughter products. In this way it is possible to have a more precise measure of the alpha activity of this isotope. The system was constructed in a stainless steel hermetic container made of the camera, a cape and a valve, the used sample was a standards of Radium 226 attained from carnotite ore. The Radon 222 alpha particles, as well as the alpha particles of its decay products namely Polonium 210. Polonium 218 and Polonium 214 were identified by a surface barrier detector. The results in this manner obtained shows clearly well definite peaks of Radon 222 and also peaks of the Radon 222 daughter products with energies of 5.43, 5.31, 6.0 and 7.69 Mev respectively. The system allows to separate and to indentify the energies of Radon and its daughter products coming directly from a standard solid sample of Radium 226 (Author)

  12. High-pressure phase equilibrium data for systems with carbon dioxide, {alpha}-humulene and trans-caryophyllene

    Energy Technology Data Exchange (ETDEWEB)

    Michielin, Eliane M.Z.; Rosso, Sibele R [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil); Franceschi, Elton; Borges, Gustavo R; Corazza, Marcos L; Oliveira, J Vladimir [Department of Food Engineering, URI - Campus de Erechim, Av. Sete de Setembro, 1621, Erechim, RS, 99700-000 (Brazil); Ferreira, Sandra R.S. [EQA/UFSC, Chemical and Food Engineering Department, Federal University of Santa Catarina, C.P. 476, CEP 88040-900, Florianopolis, SC (Brazil)], E-mail: sandra@enq.ufsc.br

    2009-01-15

    The aim of this work is to report phase equilibrium data for the binary systems (CO{sub 2} + {alpha}-humulene) and (CO{sub 2} + trans-caryophyllene), and for the ternary system (CO{sub 2} + {alpha}-humulene + trans-caryophyllene). Results from literature show that {alpha}-humulene and trans-caryophyllene are the main compounds responsible for the anti-inflammatory and anti-allergic characteristics attributed to the medicinal plant Cordia verbenacea D.C., hence giving importance to the phase behaviour investigation performed in this work. Phase equilibrium experiments were performed in a high-pressure, variable-volume view cell over the temperature range of T = (303 to 343) K and pressures up to 20 MPa. (Liquid + liquid) and (vapour + liquid + liquid) equilibrium were observed at T = 303 K, while (vapour + liquid) phase transitions were verified to occur from T = (313 to 343) K, for all systems studied. Thermodynamic modelling was performed using the Peng-Robinson equation of state and the classical quadratic mixing rules, with a satisfactory agreement between experimental and calculated values.

  13. Crystalline anhydrous {alpha},{alpha}-trehalose (polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose: A calorimetric study

    Energy Technology Data Exchange (ETDEWEB)

    Pinto, Susana S. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: susanapinto@ist.utl.pt; Diogo, Herminio P. [Centro de Quimica Estrutural, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: hdiogo@ist.utl.pt; Moura-Ramos, Joaquim J. [Centro de Quimica-Fisica Molecular, Complexo Interdisciplinar, Instituto Superior Tecnico, 1049-001 Lisbon (Portugal)]. E-mail: mouraramos@ist.utl.pt

    2006-09-15

    The mean values of the standard massic energy of combustion of crystalline anhydrous {alpha},{alpha}-trehalose (C{sub 12}H{sub 22}O{sub 11}, polymorph {beta}) and crystalline dihydrate {alpha},{alpha}-trehalose (C{sub 12}H{sub 26}O{sub 13}) measured by static-bomb combustion calorimetry in oxygen, at the temperature T=298.15K, are {delta}{sub c}u{sup o}=-(16434.05+/-4.50)J.g{sup -1} and {delta}{sub c}u{sup o}=-(14816.05+/-3.52)J.g{sup -1}, respectively. The standard (p{sup o}=0.1MPa) molar enthalpy of formation of these compounds were derived from the corresponding standard molar enthalpies of combustion, respectively, {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 22}O{sub 11},cr)=-(2240.9+/-3.9)kJ.mol{sup -1}, and {delta}{sub f}H{sub m}{sup o} (C{sub 12}H{sub 26}O{sub 13},cr)=-(2832.6+/-3.6)kJ.mol{sup -1}. The values of the standard enthalpies of formation obtained in this work, together with data on enthalpies of solution at infinite dilution ({delta}{sub sol}H{sup {approx}}) for crystalline dihydrate and amorphous anhydrous trehalose, allow a better insight on the thermodynamic description of the trehalose system which can provide, together with the future research on the subject, a contribution for understanding the metabolism in several organisms, as well as the phase transition between the different polymorphs.

  14. Direct Detection of The Lyman Continuum of Star-forming Galaxies at z~3

    Science.gov (United States)

    Vasei, Kaveh; Siana, Brian; Shapley, Alice; Alavi, Anahita; Rafelski, Marc

    2018-01-01

    Star-forming galaxies are widely believed to be responsible for the reionization of the Universe and much of the ionizing background at z>3. Therefore, there has been much interest in quantifying the escape fraction of the Lyman continuum (LyC) radiation of the star-forming galaxies. Yet direct detection of LyC has proven to be exceptionally challenging. Despite numerous efforts only 7 galaxies at z2 have been robustly confirmed as LyC leakers. To avoid these challenges many studies use indirect methods to infer the LyC escape fraction. We tested these indirect methods by attempting to detect escaping LyC with a 10-orbit Hubble near-UV (F275W) image that is just below the Lyman limit at the redshift of the Cosmic Horseshoe (a lensed galaxy at z=2.4). We concluded that the measured escape fraction is lower, by more than a factor of five, than the expected escape fraction based on the indirect methods. This emphasizes that indirect determinations should only be interpreted as upper-limits. We also investigated the deepest near-UV Hubble images of the SSA22 field to detect LyC leakage from a large sample of candidate star-forming galaxies at z~3.1, whose redshift was obtained by deep Keck/LRIS spectroscopy and for which Keck narrow-band imaging was showing possible LyC leakage. The high spatial resolution of Hubble images is crucial to confirm our detections are clean from foreground contaminating galaxies, and also to ascertain the escape fraction of our final candidates. We identify five clean LyC emitting star-forming galaxies. The follow up investigation of these galaxies will significantly increase our knowledge of the LyC escape fraction and the mechanisms allowing for LyC escape.

  15. Cosmic Metal Production and the Contribution of QSO Absorption Systems to the Ionizing Background

    Science.gov (United States)

    Madau, Piero; Shull, J. Michael

    1996-01-01

    The recent discovery by Cowie et al. (1995) and Tytler et al. (1995) of metals in the Ly alpha clouds shows that the intergalactic medium (IGM) at high redshift is contaminated by the products of stars and suggests that ionizing photons from massive star formation may be a significant contributor to the UV background radiation at early epochs. We assess the validity of the stellar photoionization hypothesis. Based on recent computations of metal yields and 0-star Lyman continuum (Lyc) fluxes, we find that 0.2 percent of the rest-mass energy of the metals produced is radiated as Lyc. By modeling the transfer of ionizing radiation through the IGM and the rate of chemical enrichment, we demonstrate that the background intensity of photons at 1 ryd that accompanies the production of metals in the Ly alpha forest clouds may be significant, approaching 0.5 x 10(exp -21) ergs cm squared s(-1) Hz(-1) sr(-1) at z approximately equals 3 if the Lyc escape fraction is greater than of equal to 0.25. Together with quasars, massive stars could then, in principle, provide the hydrogen and helium Lyc photons required to ionize the universe at high redshifts. We propose that observations of the He2 Gunn-Peterson effect and of the metal ionization states of the Ly alpha forest and Lyman-limit absorbers should show the signature of a stellar spectrum. We also note that the stellar photoionization model fails if a large fraction of the UV radiation emitted from stars cannot escape into the IGM, as suggested by the recent Hopkins Ultraviolet Telescope observations by Leitherer et al. (1995) of low-redshift starburst galaxies, or if most of the metals observed at z is approximately 3 were produced at much earlier epochs.

  16. A bar-code reader for an alpha-beta automatic counting system - FAG

    Energy Technology Data Exchange (ETDEWEB)

    Levinson, S; Shemesh, Y; Ankry, N; Assido, H; German, U; Peled, O [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    A bar-code laser system for sample number reading was integrated into the FAG Alpha-Beta automatic counting system. The sample identification by means of an attached bar-code label enables unmistakable and reliable attribution of results to the counted sample. Installation of the bar-code reader system required several modifications: Mechanical changes in the automatic sample changer, design and production of new sample holders, modification of the sample planchettes, changes in the electronic system, update of the operating software of the system (authors).

  17. A bar-code reader for an alpha-beta automatic counting system - FAG

    International Nuclear Information System (INIS)

    Levinson, S.; Shemesh, Y.; Ankry, N.; Assido, H.; German, U.; Peled, O.

    1996-01-01

    A bar-code laser system for sample number reading was integrated into the FAG Alpha-Beta automatic counting system. The sample identification by means of an attached bar-code label enables unmistakable and reliable attribution of results to the counted sample. Installation of the bar-code reader system required several modifications: Mechanical changes in the automatic sample changer, design and production of new sample holders, modification of the sample planchettes, changes in the electronic system, update of the operating software of the system (authors)

  18. Direct method gas-phase oxygen abundances of four Lyman break analogs

    Energy Technology Data Exchange (ETDEWEB)

    Brown, Jonathan S.; Croxall, Kevin V.; Pogge, Richard W. [Department of Astronomy, The Ohio State University, Columbus, OH 43201 (United States)

    2014-09-10

    We measure the gas-phase oxygen abundances in four Lyman break analogs using auroral emission lines to derive direct abundances. The direct method oxygen abundances of these objects are generally consistent with the empirically derived strong-line method values, confirming that these objects are low oxygen abundance outliers from the mass-metallicity (MZ) relation defined by star forming Sloan Digital Sky Survey galaxies. We find slightly anomalous excitation conditions (Wolf-Rayet features) that could potentially bias the empirical estimates toward high values if caution is not exercised in the selection of the strong-line calibration. The high rate of star formation and low oxygen abundance of these objects is consistent with the predictions of the fundamental metallicity relation, in which the infall of relatively unenriched gas simultaneously triggers an episode of star formation and dilutes the interstellar medium of the host galaxy.

  19. Deuterium Abundance Toward G191-B2B: Results from the Far Ultraviolet Spectroscopic Explorer (FUSE) Mission

    Science.gov (United States)

    Lemoine, M.; Vidal-Madjar, A.; Hebrard, G.; Desert, J.-M.; Ferlet, R.; LecavelierdesEtangs, A.; Howk, J. C.; Andre, M.; Blair, W. P.; Friedman, S. D.; hide

    2002-01-01

    High-resolution spectra of the hot white dwarf G191-B2B covering the wavelength region 905-1187A were obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). This data was used in conjunction with existing high-resolution Hubble Space Telescope STIS observations to evaluate the total H(sub I), D(sub I), O(sub I) and N(sub I) column densities along the line of sight. Previous determinations of N(D(sub I)) based upon GHRS (Goddard High Resolution Spectrograph) and STIS (Space Telescope Imaging Spectrograph) observations were controversial due to the saturated strength of the D(sub I) Lyman alpha line. In the present analysis the column density of D(sub I) has been measured using only the unsaturated Lyman beta and Lyman gamma lines observed by FUSE. A careful inspection of possible systematic uncertainties tied to the modeling of the stellar continuum or to the uncertainties in the FUSE instrumental character series has been performed. The column densities derived are: log N(D(sub I)) = 13.40+/-0.07, log N(O(sub I)) = 14.86+/-0.07, and log N(N(sub I)) = 13.87+/-0.07 quoted with 2sigma, uncertainties. The measurement of the H(sub I) column density by profile fitting of the Lyman alpha line has been found to be unsecure. If additional weak hot interstellar components are added to the three detected clouds along the line of sight, the H(sub I)) column density can be reduced quite significantly, even though the signal-to-noise ratio and spectral resolution at Lyman alpha are excellent. The new estimate of N(H(sub I)) toward G191-B2B reads: logN(H (sub I)) = 18.18+/-0.18 (2sigma uncertainty), so that the average (D/H) ratio on the line of sight is: (D/H)= 1.66(+0.9/-0.6) x 10(exp -5) (2sigma uncertainty).

  20. First Constraints on Fuzzy Dark Matter from Lyman-α Forest Data and Hydrodynamical Simulations.

    Science.gov (United States)

    Iršič, Vid; Viel, Matteo; Haehnelt, Martin G; Bolton, James S; Becker, George D

    2017-07-21

    We present constraints on the masses of extremely light bosons dubbed fuzzy dark matter (FDM) from Lyman-α forest data. Extremely light bosons with a de Broglie wavelength of ∼1  kpc have been suggested as dark matter candidates that may resolve some of the current small scale problems of the cold dark matter model. For the first time, we use hydrodynamical simulations to model the Lyman-α flux power spectrum in these models and compare it to the observed flux power spectrum from two different data sets: the XQ-100 and HIRES/MIKE quasar spectra samples. After marginalization over nuisance and physical parameters and with conservative assumptions for the thermal history of the intergalactic medium (IGM) that allow for jumps in the temperature of up to 5000 K, XQ-100 provides a lower limit of 7.1×10^{-22}  eV, HIRES/MIKE returns a stronger limit of 14.3×10^{-22}  eV, while the combination of both data sets results in a limit of 20×10^{-22}  eV (2σ C.L.). The limits for the analysis of the combined data sets increases to 37.5×10^{-22}  eV (2σ C.L.) when a smoother thermal history is assumed where the temperature of the IGM evolves as a power law in redshift. Light boson masses in the range 1-10×10^{-22}  eV are ruled out at high significance by our analysis, casting strong doubts that FDM helps solve the "small scale crisis" of the cold dark matter models.

  1. Alpha detection on moving surfaces

    International Nuclear Information System (INIS)

    MacArthur, D.; Orr, C.; Luff, C.

    1998-01-01

    Both environmental restoration (ER) and decontamination and decommissioning (D and D) require characterization of large surface areas (walls, floors, in situ soil, soil and rubble on a conveyor belt, etc.) for radioactive contamination. Many facilities which have processed alpha active material such as plutonium or uranium require effective and efficient characterization for alpha contamination. Traditional methods for alpha surface characterization are limited by the short range and poor penetration of alpha particles. These probes are only sensitive to contamination located directly under the probe. Furthermore, the probe must be held close to the surface to be monitored in order to avoid excessive losses in the ambient air. The combination of proximity and thin detector windows can easily cause instrument damage unless extreme care is taken. The long-range alpha detection (LRAD) system addresses these problems by detecting the ions generated by alpha particles interacting with ambient air rather than the alpha particle directly. Thus, detectors based on LRAD overcome the limitations due to alpha particle range (the ions can travel many meters as opposed to the several-centimeter alpha particle range) and penetrating ability (an LRAD-based detector has no window). Unfortunately, all LRAD-based detectors described previously are static devices, i.e., these detectors cannot be used over surfaces which are continuously moving. In this paper, the authors report on the first tests of two techniques (the electrostatic ion seal and the gridded electrostatic LRAD detector) which extend the capabilities of LRAD surface monitors to use over moving surfaces. This dynamic surface monitoring system was developed jointly by Los Alamos National Laboratory and at BNFL Instruments. All testing was performed at the BNFL Instruments facility in the UK

  2. Alpha-in-air monitor for continuous monitoring based on alpha to beta ratio

    International Nuclear Information System (INIS)

    Somayaji, K.S.; Venkataramani, R.; Swaminathan, N.; Pushparaja

    1997-01-01

    Measurement of long-lived alpha activity collected on a filter paper in continuous air monitoring of ambient working environment is difficult due to interference from much larger concentrations of short-lived alpha emitting daughter products of 222 Rn and 220 Rn. However, the ratio between the natural alpha and beta activity is approximately constant and this constancy of the ratio is used to discriminate against short-lived natural radioactivity in continuous air monitoring. Detection system was specially designed for the purpose of simultaneous counting of alpha and beta activity deposited on the filter paper during continuous monitoring. The activity ratios were calculated and plotted against the monitoring duration up to about six hours. Monitoring was carried out in three facilities with different ventilation conditions. Presence of any long-lived alpha contamination on the filter paper results in increase in the alpha to beta ratio. Long-lived 239 Pu contamination of about 16 DAC.h could be detected after about 45 minutes of commencement of the sampling. The experimental results using prototype units have shown that the approach of using alpha to beta activity ratio method to detect long-lived alpha activity in the presence of short-lived natural activity is satisfactory. (author)

  3. DETECTIONS OF LYMAN CONTINUUM FROM STAR-FORMING GALAXIES AT z ∼ 3 THROUGH SUBARU/SUPRIME-CAM NARROW-BAND IMAGING

    International Nuclear Information System (INIS)

    Iwata, I.; Inoue, A. K.; Matsuda, Y.; Furusawa, H.; Akiyama, M.; Hayashino, T.; Kousai, K.; Yamada, T.; Burgarella, D.; Deharveng, J.-M.

    2009-01-01

    Knowing the amount of ionizing photons from young star-forming galaxies is of particular importance to understanding the reionization process. Here we report initial results of a Subaru/Suprime-Cam deep imaging observation of the SSA22 proto-cluster region at z = 3.09, using a special narrow-band filter to optimally trace ionizing radiation from galaxies at z ∼ 3. The unique wide field-of-view of Suprime-Cam enabled us to search for ionizing photons from 198 galaxies (73 Lyman break galaxies (LBGs) and 125 Lyα emitters (LAEs)) with spectroscopically measured redshifts z ≅ 3.1. We detected ionizing radiation from 7 LBGs, as well as from 10 LAE candidates. Some of the detected galaxies show significant spatial offsets of ionizing radiation from nonionizing UV emission. For some LBGs the observed nonionizing UV to Lyman continuum flux density ratios are smaller than values expected from population synthesis models with a standard Salpeter initial mass function (IMF) with moderate dust attenuation (which is suggested from the observed UV slopes), even if we assume very transparent intergalactic medium along the sightlines of these objects. This implies an intrinsically bluer spectral energy distribution, e.g., that produced by a top-heavy IMF, for these LBGs. The observed flux density ratios of nonionizing UV to ionizing radiation of 7 detected LBGs range from 2.4 to 23.8 and the median is 6.6. The observed flux density ratios of the detected LAEs are even smaller than LBGs, if they are truly at z ≅ 3.1. We find that the median value of the flux density ratio for the detected LBGs suggests that their escape fractions are likely to be higher than 4%, if the Lyman continuum escape is isotropic. The results imply that some of the LBGs in the proto-cluster at z ∼ 3 have escape fraction significantly higher than that of galaxies (in a general field) at z ∼ 1 studied previously.

  4. Evidence for Black Hole Growth in Local Analogs to Lyman Break Galaxies

    Science.gov (United States)

    Jia, Jianjun; Ptak, Andrew; Heckman, Timothy M.; Overzier, Roderik A.; Hornschemeier, Ann; LaMassa, Stephanie M.

    2011-01-01

    We have used XMM-Newton to observe six Lyman break analogs (LBAs): members of the rare population of local galaxies that have properties that are very similar to distant Lyman break galaxies. Our six targets were specifically selected because they have optical emission-line properties that are intermediate between starbursts and Type 2 (obscured) active galactic nuclei (AGNs). Our new X-ray data provide an important diagnostic of the presence of an AGN. We find X-ray luminosities of order 10(sup 42) erg per second and ratios of X-ray to far-IR lummositles that are higher than values in pure starburst galaxies by factors ranging from approximately 3 to 30. This strongly suggests the presence of an AGN in at least some of the galaxies. The ratios of the luminosities of the hard (2-10 keV) X-ray to [O III] emission line are low by about an order of magnitude compared with Type 1 AGN, but are consistent with the broad range seen in Type 2 AGN. Either the AGN hard X-rays are significantly obscured or the [O III] emission is dominated by the starburst. We searched for an iron emission line at approximately 6.4 ke V, which is a key feature of obscured AGNs, but only detected emission at the approximately 2sigma level. Finally, we find that the ratios of the mid-infrared (24 micrometer) continuum to [O III]lambda 5007 luminosities in these LBAs are higher than the values for Type 2 AGN by an average of 0.8 dex. Combining all these clues, we conclude that an AGN is likely to be present, but that the bolometric luminosity is produced primarily by an intense starburst. If these black holes are radiating at the Eddington limit, their masses would lie in the range of 10(sup 5) - 10(sup 6) solar mass. These objects may offer ideal local laboratories to investigate the processes by which black holes grew in the early universe.

  5. The low-ion QSO absorption-line systems

    International Nuclear Information System (INIS)

    Lanzetta, K.M.

    1988-01-01

    Various techniques are used to investigate the class of QSO absorption-line systems that exhibit low-ion absorption lines. Four separate investigations are conducted as follows: Spectroscopy of 32 QSOs at red wavelengths is presented and used to investigate intermediate-redshift MgII absorption. A total of 22 Mg II doublets are detected, from which properties of the Mg II absorbers are derived. Marginal evidence for intrinsic evolution of the number density of the Mg II absorbers with redshift is found. The data are combined with previous observations of C IV and C II seen in the same QSOs at blue wavelengths, and the properties of Mg II- and C IV-selected systems are compared. A sample is constructed of 129 QSOs for which are available published data suitable for detecting absorption-line systems that are optically thick to Lyman continuum radiation. A total of 53 such Lyman-limit systems are found, from which properties of the Lyman-limit systems are derived. It is found that the rate of incidence of the systems does not strongly evolved with redshift. This result is contrasted with the evolution found previously for systems selected on the basis of Mg II absorption. Spectroscopy at red wavelengths of eight QSOs with known damped Lyα absorption systems is presented. Spectroscopic and spectrophotometric observations aimed at detecting molecular hydrogen and dust in the z = 2.796 damped Lyα absorber toward Q1337 + 113 are presented

  6. SCORE - Sounding-rocket Coronagraphic Experiment

    Science.gov (United States)

    Fineschi, Silvano; Moses, Dan; Romoli, Marco

    The Sounding-rocket Coronagraphic Experiment - SCORE - is a The Sounding-rocket Coronagraphic Experiment - SCORE - is a coronagraph for multi-wavelength imaging of the coronal Lyman-alpha lines, HeII 30.4 nm and HI 121.6 nm, and for the broad.band visible-light emission of the polarized K-corona. SCORE has flown successfully in 2009 acquiring the first images of the HeII line-emission from the extended corona. The simultaneous observation of the coronal Lyman-alpha HI 121.6 nm, has allowed the first determination of the absolute helium abundance in the extended corona. This presentation will describe the lesson learned from the first flight and will illustrate the preparations and the science perspectives for the second re-flight approved by NASA and scheduled for 2016. The SCORE optical design is flexible enough to be able to accommodate different experimental configurations with minor modifications. This presentation will describe one of such configurations that could include a polarimeter for the observation the expected Hanle effect in the coronal Lyman-alpha HI line. The linear polarization by resonance scattering of coronal permitted line-emission in the ultraviolet (UV) can be modified by magnetic fields through the Hanle effect. Thus, space-based UV spectro-polarimetry would provide an additional new tool for the diagnostics of coronal magnetism.

  7. The effect of asymmetric solar wind on the Lyman α sky background

    International Nuclear Information System (INIS)

    Joselyn, J.A.; Holzer, T.E.

    1975-01-01

    The Lyman α (Ly α) sky background arises from the scattering of solar Ly α from a spatial distribution of neutral hydrogen in interplanetary space. This distribution is partially determined by the solar wind proton flux, which provides the principal mechanism of loss by charge exchange of the neutral hydrogen. By generating isophotal maps of scattered Ly α for several choices of interstellar wind direction and solar wind proton flux distributions, the results show that latitudinal variations of the solar wind proton flux can have a significant effect on the observed location and shape of the Ly α intensity maximum. This fact should aid in the interpretation of Ly α maps and also indicates a possible method for inferring values for the average solar wind proton flux out of the ecliptic plane

  8. EUV properties of two diffraction gratings

    International Nuclear Information System (INIS)

    Cotton, D.; Chakrabarti, S.; Edelstein, J.; Pranke, J.; Christensen, A.B.

    1988-01-01

    The efficiency and scattering characteristics of a mechanically ruled grating (MRG) and a holographically ruled grating (HRG) are presented. One of these gratings will be employed in the Extreme Ultraviolet Spectrometer, an instrument of the Remote Atmospheric and Ionospheric Detector System to be flown aboard a TIROS satellite in 1991. The HRG showed much less Lyman alpha scattering, while the MRG had the better efficiency over most of the spectral range covered. 8 refs

  9. Stability of Multi-Planet Systems in the Alpha Centauri System

    Science.gov (United States)

    Lissauer, Jack J.

    2017-01-01

    We evaluate the extent of the regions within the alpha Centauri AB star system where small planets are able to orbit for billion-year timescales (Quarles & Lissauer 2016, Astron. J. 151, 111), as well as how closely-spaced planetary orbits can be within those regions in which individual planets can survive. Although individual planets on low inclination, low eccentricity, orbits can survive throughout the habitable zones of both stars, perturbations from the companion star imply that the spacing of planets in multi-planet systems within the habitable zones of each star must be significantly larger than the spacing of similar multi-planet systems orbiting single stars in order to be long-lived. Because the binary companion induces a forced eccentricity upon the orbits of planets in orbit around either star, appropriately-aligned circumstellar orbits with small initial eccentricities are stable to slightly larger initial semimajor axes than are initially circular orbits. Initial eccentricities close to forced eccentricities can have a much larger affect on how closely planetary orbits can be spaced, and therefore on how many planets may remain in the habitable zones, although the required spacing remains significantly higher than for planets orbiting single stars.

  10. Expression and functional importance of collagen-binding integrins, alpha 1 beta 1 and alpha 2 beta 1, on virus-activated T cells

    DEFF Research Database (Denmark)

    Andreasen, Susanne Ø; Thomsen, Allan R; Koteliansky, Victor E

    2003-01-01

    decreased responses were seen upon transfer of alpha(1)-deficient activated/memory T cells. Thus, expression of alpha(1)beta(1) and alpha(2)beta(1) integrins on activated T cells is directly functionally important for generation of inflammatory responses within tissues. Finally, the inhibitory effect......Adhesive interactions are crucial to cell migration into inflammatory sites. Using murine lymphocytic choriomeningitis virus as an Ag model system, we have investigated expression and function of collagen-binding integrins, alpha(1)beta(1) and alpha(2)beta(1), on activated and memory T cells. Using...... this system and MHC tetramers to define Ag-specific T cells, we demonstrate that contrary to being VLAs, expression of alpha(1)beta(1) and alpha(2)beta(1) can be rapidly induced on acutely activated T cells, that expression of alpha(1)beta(1) remains elevated on memory T cells, and that expression of alpha(1...

  11. Alpha spectral analysis via artificial neural networks

    International Nuclear Information System (INIS)

    Kangas, L.J.; Hashem, S.; Keller, P.E.; Kouzes, R.T.; Troyer, G.L.

    1994-10-01

    An artificial neural network system that assigns quality factors to alpha particle energy spectra is discussed. The alpha energy spectra are used to detect plutonium contamination in the work environment. The quality factors represent the levels of spectral degradation caused by miscalibration and foreign matter affecting the instruments. A set of spectra was labeled with a quality factor by an expert and used in training the artificial neural network expert system. The investigation shows that the expert knowledge of alpha spectra quality factors can be transferred to an ANN system

  12. Stationary inverted Lyman population formed from incandescently heated hydrogen gas with certain catalysts

    International Nuclear Information System (INIS)

    Mills, Randell L; Ray, Paresh C; Mayo, Robert M

    2003-01-01

    A new chemically generated plasma source is reported. The presence of gaseous Rb + or K + ions with thermally dissociated hydrogen formed a low applied temperature, extremely low voltage plasma called a resonant transfer or rt-plasma having strong vacuum ultraviolet emission. We propose an energetic catalytic reaction involving a resonant energy transfer between hydrogen atoms and Rb + or 2K + since Rb + to Rb 2+ , 2K + to K + K 2+ , and K to K 3+ each provide a reaction with a net enthalpy equal to the potential energy of atomic hydrogen. Remarkably, a stationary inverted Lyman population was observed; thus, these catalytic reactions may pump a cw HI laser as predicted by a collisional radiative model used to determine that the observed overpopulation was above threshold

  13. A comparison of photospheric electric current and ultraviolet and X-ray emission in a solar active region

    Science.gov (United States)

    Haisch, B. M.; Bruner, M. E.; Hagyard, M. J.; Bonnet, R. M.

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft X-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region.

  14. Comparison of photospheric electric current and ultraviolet and x-ray emission in a solar active region

    International Nuclear Information System (INIS)

    Haisch, B.M.; Bruner, M.E.; Hagyard, M.J.; Bonnet, R.M.; NASA, Marshall Space Flight Center, Huntsville, AL; ESA, Paris, France)

    1986-01-01

    This paper presents an extensive set of coordinated observations of a solar active region, taking into account spectroheliograms obtained with the aid of the Solar Maximum Mission (SMM) Ultraviolet Spectrometer Polarimeter (UVSP) instrument, SMM soft x-ray polychromator (XRP) raster maps, and high spatial resolution ultraviolet images of the sun in Lyman-alpha and in the 1600 A continuum. These data span together the upper solar atmosphere from the temperature minimum to the corona. The data are compared to maps of the inferred photospheric electric current derived from the Marshall Space Flight Center (MSFC) vector magnetograph observations. Some empirical correlation is found between regions of inferred electric current density and the brightest features in the ultraviolet continuum and to a lesser extent those seen in Lyman-alpha within an active region. 29 references

  15. Development of thermal conditioning technology for Alpha-containment wastes: Alpha-contaminated waste incineration technology

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Joon Hyung; Kim, Jeong Guk; Yang, Hee Chul; Choi, Byung Seon; Jeong, Myeong Soo

    1999-03-01

    As the first step of a 3-year project named 'development of alpha-contaminated waste incineration technology', the basic information and data were reviewed, while focusing on establishment of R and D direction to develop the final goal, self-supporting treatment of {alpha}- wastes that would be generated from domestic nuclear industries. The status on {alpha} waste incineration technology of advanced states was reviewed. A conceptual design for {alpha} waste incineration process was suggested. Besides, removal characteristics of volatile metals and radionuclides in a low-temperature dry off-gas system were investigated. Radiation dose assessments and some modification for the Demonstration-scale Incineration Plant (DSIP) at Korea Atomic Energy Research Institute (KAERI) were also done.

  16. Determination of alpha activity and fissile mass content in solid waste by systems using neutron interrogation

    International Nuclear Information System (INIS)

    Romeyer Dherbey, J.; Lacruche, G.; Berne, R.; Auge, J.; Martin Deidier, L.; Butez, M.

    1990-01-01

    The Quantitative control (determination of heavy nuclides and alpha activity) of alpha radioactive wastes is necessary, particularly to determine if the waste is in accordance with the surface storage limits. In order to reduce the uncertainty on the alpha activity resulting from unknown isotopic composition, inhomogeneity of heavy nuclides in the matrix, combination of several methods is necessary. In the paper we present the Cadarache development work in the NDA of solid waste using the Californium shuffler, 14 Mev neutron generator, and also passive techniques such as neutron emission measurement and gamma spectrometry. Experimental systems combining active and passive methods are presented (COSAC, BANCO, DANAIDE, PROMETHEE)

  17. Orbital Eccentricity and the Stability of Planets in the Alpha Centauri System

    Science.gov (United States)

    Lissauer, Jack

    2016-01-01

    Planets on initially circular orbits are typically more dynamically stable than planets initially having nonzero eccentricities. However, the presence of a major perturber that forces periodic oscillations of planetary eccentricity can alter this situation. We investigate the dependance of system lifetime on initial eccentricity for planets orbiting one star within the alpha Centauri system. Our results show that initial conditions chosen to minimize free eccentricity can substantially increase stability compared to planets on circular orbits.

  18. Alpha particles spectrometer with photodiode PIN

    International Nuclear Information System (INIS)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R.; Ramirez G, J.

    2009-10-01

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  19. Weak lensing of the Lyman α forest

    Science.gov (United States)

    Croft, Rupert A. C.; Romeo, Alessandro; Metcalf, R. Benton

    2018-06-01

    The angular positions of quasars are deflected by the gravitational lensing effect of foreground matter. The Lyman α (Lyα) forest seen in the spectra of these quasars is therefore also lensed. We propose that the signature of weak gravitational lensing of the Lyα forest could be measured using similar techniques that have been applied to the lensed cosmic microwave background (CMB), and which have also been proposed for application to spectral data from 21-cm radio telescopes. As with 21-cm data, the forest has the advantage of spectral information, potentially yielding many lensed `slices' at different redshifts. We perform an illustrative idealized test, generating a high-resolution angular grid of quasars (of order arcminute separation), and lensing the Lyα forest spectra at redshifts z = 2-3 using a foreground density field. We find that standard quadratic estimators can be used to reconstruct images of the foreground mass distribution at z ˜ 1. There currently exists a wealth of Lyα forest data from quasar and galaxy spectral surveys, with smaller sightline separations expected in the future. Lyα forest lensing is sensitive to the foreground mass distribution at redshifts intermediate between CMB lensing and galaxy shear, and avoids the difficulties of shape measurement associated with the latter. With further refinement and application of mass reconstruction techniques, weak gravitational lensing of the high-redshift Lyα forest may become a useful new cosmological probe.

  20. CAMEX-4 NOAA LYMAN-ALPHA HYGROMETER V1

    Data.gov (United States)

    National Aeronautics and Space Administration — Ozone is measured in situ using a photometer consisting of a mercury lamp, two sample chambers and two detectors. The detectors measure the 254nm radiation...

  1. High-resolution Lyman-alpha filtergrams of the sun

    International Nuclear Information System (INIS)

    Bonnet, R.M.; Bruner, E.C. Jr.; Acton, L.W.; Brown, W.A.; Decaudin, M.

    1980-01-01

    1'' resolution Lα pictures of the Sun have been obtained during the flight of a Black Brant rocket which took place on 1979 July 3. These pictures reveal many new structures never seen before on Lα spectroheliograms. The instrumentation, flight conditions, and preliminary results are described

  2. Radon compensation for alpha air monitoring systems

    International Nuclear Information System (INIS)

    Fleming, D.M.; Rising, F.L.; Zuerner, L.V.

    1975-01-01

    Continuous alpha air monitors, employing solid state detectors and single channel analyzers, for the detection of alpha particles of a specific energy have been available commercially for several years. The single channel pulse height analyzers provide good sensitivity to the isotope of interest and reject much of the unwanted activity from other isotopes such as naturally occurring radon and daughters. A small percentage of the radon daughters are degraded in energy by the air between the collecting filter and the diode to the extent that they coincide with energy of the isotope being measured and are counted as unwanted background. When 239 Pu is the isotope being measured the activity in the Pu channel resulting from radon is typically 2 percent of the total radon background. The majority of this unwanted background results from the degradation of the 6.0 MeV 218 Po (RaA) peak. This background is sufficient to cause instrument alarms during periods of radon activity. In attempts to reduce the frequency of false alarms, background subtraction circuits have been added as standard equipment to most of the alpha air monitors available on the market for the past several years. A method for calibrating these background subtraction circuits using a radon generator is described. (U.S.)

  3. Multi-isotopic gamma-ray assay system for alpha-contaminated waste

    International Nuclear Information System (INIS)

    Close, D.A.; Pratt, J.C.; Caldwell, J.T.; Kunz, W.E.; Schultz, F.J.; Haff, K.W.

    1983-01-01

    The capability of an existing segmented gamma-ray system is being expanded for the analysis of alpha-contaminated waste drums. A cursory assay of 114 transuranic waste drums of 208-l capacity has been made. Analysis of these data indicates a detection limit better than 100 nCi/g of waste for 237 Np/ 233 Pa, 239 Pu, 241 Am, 243 Am/ 239 Np, 60 Co, 125 Sb, 134 137 Cs, and 154 Eu. A pending Code of Federal Regulation (10CFR61) stipulates that the nuclear industry quantify not only its transuranic waste, but also certain beta- and gamma-ray-emitting fission products. An assay system based on gamma-ray spectroscopy is the only system that can meet this requirement for the fission products

  4. Extrasynaptic location of alpha-2 and noninnervated beta-2 adrenoceptors in the vascular system of the pithed normotensive rat

    NARCIS (Netherlands)

    Wilffert, B.; Timmermans, P.B.M.W.M.; Van Zwieten, P.A.

    1982-01-01

    The receptors involved in the pressor and tachycardic effects of catecholamines applied systemically or released from sympathetic nerve endings were compared. Intravenously administered (-)-epinephrine activated alpha-1, alpha-2, beta-1 and beta-2 adrenoceptors as demonstrated in pithed rats, using

  5. The Lyman continuum escape fraction of galaxies at z = 3.3 in the VUDS-LBC/COSMOS field

    Science.gov (United States)

    Grazian, A.; Giallongo, E.; Gerbasi, R.; Fiore, F.; Fontana, A.; Le Fèvre, O.; Pentericci, L.; Vanzella, E.; Zamorani, G.; Cassata, P.; Garilli, B.; Le Brun, V.; Maccagni, D.; Tasca, L. A. M.; Thomas, R.; Zucca, E.; Amorín, R.; Bardelli, S.; Cassarà, L. P.; Castellano, M.; Cimatti, A.; Cucciati, O.; Durkalec, A.; Giavalisco, M.; Hathi, N. P.; Ilbert, O.; Lemaux, B. C.; Paltani, S.; Ribeiro, B.; Schaerer, D.; Scodeggio, M.; Sommariva, V.; Talia, M.; Tresse, L.; Vergani, D.; Bonchi, A.; Boutsia, K.; Capak, P.; Charlot, S.; Contini, T.; de la Torre, S.; Dunlop, J.; Fotopoulou, S.; Guaita, L.; Koekemoer, A.; López-Sanjuan, C.; Mellier, Y.; Merlin, E.; Paris, D.; Pforr, J.; Pilo, S.; Santini, P.; Scoville, N.; Taniguchi, Y.; Wang, P. W.

    2016-01-01

    Context. The ionizing Lyman continuum flux escaping from high-redshift galaxies into the intergalactic medium is a fundamental quantity to understand the physical processes involved in the reionization epoch. However, from an observational point of view, direct detections of HI ionizing photons at high redshifts are feasible for galaxies mainly in the interval z ~ 3-4. Aims: We have investigated a sample of star-forming galaxies at z ~ 3.3 to search for possible detections of Lyman continuum ionizing photons escaping from galaxy halos. Methods: We used deep ultraviolet (UV) imaging in the COSMOS field, obtained with the prime focus camera LBC at the LBT telescope, along with a catalogue of spectroscopic redshifts obtained by the VIMOS Ultra Deep Survey (VUDS) to build a sample of 45 galaxies at z ~ 3.3 with L> 0.5 L∗. We obtained deep LBC images of galaxies with spectroscopic redshifts in the interval 3.27 28%, but a detailed analysis of their properties reveals that, with the exception of two marginal detections (S/N ~ 2) in the U-band, all the other eight galaxies are most likely contaminated by the UV flux of low-redshift interlopers located close (in angular position) to the high-z targets. The average escape fraction derived from the stacking of the cleaned sample was constrained to fescrel Chile, under Large Programme 185.A-0791 and on observations made at the Large Binocular Telescope (LBT) at Mt. Graham (Arizona, USA).

  6. Treatment of alpha bearing wastes

    International Nuclear Information System (INIS)

    1988-01-01

    This report deals with the current state of the art of alpha waste treatment, which is an integral part of the overall nuclear waste management system. The International Atomic Energy Agency (IAEA) defines alpha bearing waste as 'waste containing one or more alpha emitting radionuclides, usually actinides, in quantities above acceptable limits'. The limits are established by national regulatory bodies. The limits above which wastes are considered as alpha contaminated refer to the concentrations of alpha emitters that need special consideration for occupational exposures and/or potential safety, health, or environmental impact during one or more steps from generation through disposal. Owing to the widespread use of waste segregation by source - that is, based upon the 'suspect origin' of the material - significant volumes of waste are being handled as alpha contaminated which, in fact, do not require such consideration by reason of risk or environmental concern. The quantification of de minimis concepts by national regulatory bodies could largely contribute to the safe reduction of waste volumes and associated costs. Other factors which could significantly contribute to the reduction of alpha waste arisings are an increased application of assaying and sorting, instrumentation and the use of feedback mechanisms to control or modify the processes which generate these wastes. Alpha bearing wastes are generated during fabrication and reprocessing of nuclear fuels, decommissioning of alpha contaminated facilities, and other activities. Most alpha wastes are contact handled, but a small portion may require shielding or remote handling because of high levels of neutron (n), beta (β), or gamma (γ) emissions associated with the waste material. This report describes the sources and characteristics of alpha wastes and strategies for alpha waste management. General descriptions of treatment processes for solid and liquid alpha wastes are included. 71 refs, 14 figs, 9 tabs

  7. Lyman continuum escape fraction of faint galaxies at z 3.3 in the CANDELS/GOODS-North, EGS, and COSMOS fields with LBC

    Science.gov (United States)

    Grazian, A.; Giallongo, E.; Paris, D.; Boutsia, K.; Dickinson, M.; Santini, P.; Windhorst, R. A.; Jansen, R. A.; Cohen, S. H.; Ashcraft, T. A.; Scarlata, C.; Rutkowski, M. J.; Vanzella, E.; Cusano, F.; Cristiani, S.; Giavalisco, M.; Ferguson, H. C.; Koekemoer, A.; Grogin, N. A.; Castellano, M.; Fiore, F.; Fontana, A.; Marchi, F.; Pedichini, F.; Pentericci, L.; Amorín, R.; Barro, G.; Bonchi, A.; Bongiorno, A.; Faber, S. M.; Fumana, M.; Galametz, A.; Guaita, L.; Kocevski, D. D.; Merlin, E.; Nonino, M.; O'Connell, R. W.; Pilo, S.; Ryan, R. E.; Sani, E.; Speziali, R.; Testa, V.; Weiner, B.; Yan, H.

    2017-06-01

    Context. The reionization of the Universe is one of the most important topics of present-day astrophysical research. The most plausible candidates for the reionization process are star-forming galaxies, which according to the predictions of the majority of the theoretical and semi-analytical models should dominate the H I ionizing background at z ≳ 3. Aims: We measure the Lyman continuum escape fraction, which is one of the key parameters used to compute the contribution of star-forming galaxies to the UV background. It provides the ratio between the photons produced at λ ≤ 912 Å rest-frame and those that are able to reach the inter-galactic medium, I.e. that are not absorbed by the neutral hydrogen or by the dust of the galaxy's inter-stellar medium. Methods: We used ultra-deep U-band imaging (U = 30.2 mag at 1σ) from Large Binocular Camera at the Large Binocular Telescope (LBC/LBT) in the CANDELS/GOODS-North field and deep imaging in the COSMOS and EGS fields in order to estimate the Lyman continuum escape fraction of 69 star-forming galaxies with secure spectroscopic redshifts at 3.27 ≤ z ≤ 3.40 to faint magnitude limits (L = 0.2L∗, or equivalently M1500 - 19). The narrow redshift range implies that the LBC U-band filter exclusively samples the λ ≤ 912 Å rest-frame wavelengths. Results: We measured through stacks a stringent upper limit (L∗), while for the faint population (L = 0.2L∗) the limit to the escape fraction is ≲ 10%. We computed the contribution of star-forming galaxies to the observed UV background at z 3 and find that it is not sufficient to keep the Universe ionized at these redshifts unless their escape fraction increases significantly (≥ 10%) at low luminosities (M1500 ≥ - 19). Conclusions: We compare our results on the Lyman continuum escape fraction of high-z galaxies with recent estimates in the literature, and discuss future prospects to shed light on the end of the Dark Ages. In the future, strong gravitational

  8. Summary of [alpha]-FLOW, a general purpose three-dimensional fluid analyzing system. Han[prime]yo sanjigen ryutai kaiseki system [alpha]-FLOW no gaiyo

    Energy Technology Data Exchange (ETDEWEB)

    Koike, H [Fuji Research Institute Corporation, Tokyo (Japan)

    1992-08-01

    The [alpha]-FLOW is a three-dimensional fluid analyzing software developed from cooperations among research institutes of private business companies and universities in Japan under the assistance from the Ministry of International Trade and Industry. This paper describes its summary and features. The system is a discrete system utilizing a supercomputer and a work station. The analysis modules incorporated in the system include those for non-compressive fluid analysis, compressive fluid analysis, analysis of non-compressive fluid including free surface, analysis of flows including combustion and chemical reactions, substance migration analysis, and heat transfer analysis. It has a feature that even non-specialists can analyze fluids easily as a result of the development of an expert system to support the numerical analysis. Development of the input data preparing system enables to utilize the work station to process from shape modeling to grid generation, and from inputting analyzing condition data to calculating the flows and outputting the calculation result, all in dialogue modes. An open architecture was adopted. 27 refs., 7 figs., 10 tabs.

  9. STELLAR POPULATIONS OF LYMAN BREAK GALAXIES AT z ≅ 1-3 IN THE HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS

    International Nuclear Information System (INIS)

    Hathi, N. P.; McCarthy, P. J.; Cohen, S. H.; Windhorst, R. A.; Rutkowski, M. J.; Ryan, R. E. Jr.; Koekemoer, A. M.; Bond, H. E.; Finkelstein, S. L.; Yan, H.; O'Connell, R. W.; Straughn, A. N.; Kimble, R. A.; Balick, B.; Calzetti, D.; Disney, M. J.; Dopita, M. A.; Frogel, Jay A.; Hall, D. N. B.; Holtzman, J. A.

    2013-01-01

    We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z ≅ 1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 arcmin 2 in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z ≅ 1-3 are selected using dropout selection criteria similar to high-redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout-selected LBGs is accurate to within few percent; (2) the UV spectral slope β is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at z ≅ 1-3 are massive, dustier, and more highly star forming, compared to LBGs at higher redshifts with similar luminosities (0.1L* ∼ 3, a true Lyman break selection at z ≅ 2 is essential. The future HST UV surveys, both wider and deeper, covering a large luminosity range are important to better understand LBG properties and their evolution.

  10. Effects of local anesthetics on cholinergic agonist binding affinity of central nervous system. cap alpha. -bungarotoxin receptors

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, R.L.; Bennett, E.L.

    1979-12-01

    In general, pharmacological effects of local anesthetics may be attributed to their ability to reversibly block the propagation of nerve and muscle action potentials. At physiologically potent concentrations, local anesthetics (LA) also act as noncompetitive antagonists of the physiological response of post-synaptic nicotinic acetylcholine receptors (nAChR) to cholinergic agonists, and increase agonist binding affinities of nAChR from electric organ. It is postulated that the primary site of LA action on nAChR function is at the receptor-coupled ionophore. Furthermore, LA-nAChR ionophore interactions are thought to accelerate physiological desensitization of nAChR, manifest biochemically as increased affinity of nAChR for agonist. Specific receptors for ..cap alpha..-bungarotoxin (..cap alpha..-Bgt), a potent competitive antagonist at nAChR sites in the periphery, have been detected in rat central nervous system membrane preparations. The affinity of these central ..cap alpha..-Bgt receptors (..cap alpha..-BgtR) for cholinergic agonists is found to increase on exposure to agonist. Nevertheless, on the basis of inconsistent pharmacological and physiological results, uncertainty remains regarding the relationship between ..cap alpha..-BgtR and authentic nAChR in the CNS, despite a wide body of biochemical and histological evidence consistent with their identity. Reasoning that if CNS ..cap alpha..-BgtR are true in nAChR, coupled to functional ion channels, LA might be expected to cause biochemically measurable increases in ..cap alpha..-BgtR affinity for cholinergic agonists, we have undertaken a study of the effects of LA on the ability of acetylcholine (ACh) to inhibit interaction of ..cap alpha..-BgtR with /sup 3/H-labeled ..cap alpha..-Bgt.

  11. Geocoronal imaging with Dynamics Explorer

    Science.gov (United States)

    Rairden, R. L.; Frank, L. A.; Craven, J. D.

    1986-01-01

    The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer.

  12. Alpha oscillations and early stages of visual encoding

    Directory of Open Access Journals (Sweden)

    Wolfgang eKlimesch

    2011-05-01

    Full Text Available For a long time alpha oscillations have been functionally linked to the processing of visual information. Here we propose an new theory about the functional meaning of alpha. The central idea is that synchronized alpha reflects a basic processing mode that controls access to information stored in a complex long-term memory system, which we term knowledge system (KS in order to emphasize that it comprises not only declarative memories but any kind of knowledge comprising also procedural information. Based on this theoretical background, we assume that during early stages of perception, alpha ‘directs the flow of information’ to those neural structures which represent information that is relevant for encoding. The physiological function of alpha is interpreted in terms of inhibition. We assume that alpha enables access to stored information by inhibiting task irrelevant neuronal structures and by timing cortical activity in task relevant neuronal structures. We discuss a variety findings showing that evoked alpha and phase locking reflect successful encoding of global stimulus features in an early poststimulus interval of about 0 - 150 ms.

  13. Distribution of alpha3, alpha5 and alpha(v) integrin subunits in mature and immature human oocytes.

    Science.gov (United States)

    Capmany, G; Mart, M; Santaló, J; Bolton, V N

    1998-10-01

    The distribution of three integrin subunits, alpha3, alpha5 and alpha(v), in immature and mature human oocytes has been examined using immunofluorescence and confocal microscopy. The results demonstrate that both alpha5 and alpha(v) are present at the germinal vesicle stage, while alpha3 was only detected in oocytes after germinal vesicle breakdown, in metaphase I and II stage oocytes. The cortical concentration of integrin subunits alpha3 and alpha5 is consistent with their localization in the oolemma. In contrast, the homogeneous distribution of alpha(v) throughout the oocyte suggests the existence of cytoplasmic reservoirs of this protein in the oocyte.

  14. Low-Cost alpha Alane for Hydrogen Storage

    Energy Technology Data Exchange (ETDEWEB)

    Fabian, Tibor [Ardica Technologies, San Francisco, CA (United States); Petrie, Mark [SRI International, Menlo Park, CA (United States); Crouch-Baker, Steven [SRI International, Menlo Park, CA (United States); Fong, Henry [SRI International, Menlo Park, CA (United States)

    2017-10-10

    This project was directed towards the further development of the Savannah River National Laboratory (SRNL) lab-scale electrochemical synthesis of the hydrogen storage material alpha-alane and Ardica Technologies-SRI International (SRI) chemical downstream processes that are necessary to meet DoE cost metrics and transition alpha-alane synthesis to an industrial scale. Ardica has demonstrated the use of alpha-alane in a fuel-cell system for the U.S. Army WFC20 20W soldier power system that has successfully passed initial field trials with individual soldiers. While alpha-alane has been clearly identified as a desirable hydrogen storage material, cost-effective means for its production and regeneration on a scale of use applicable to the industry have yet to be established. We focused on three, principal development areas: 1. The construction of a comprehensive engineering techno-economic model to establish the production costs of alpha-alane by both electrochemical and chemical routes at scale. 2. The identification of critical, cost-saving design elements of the electrochemical cell and the quantification of the product yields of the primary electrochemical process. A moving particle-bed reactor design was constructed and operated. 3. The experimental quantification of the product yields of candidate downstream chemical processes necessary to produce alpha-alane to complete the most cost-effective overall manufacturing process. Our techno-economic model shows that under key assumptions most 2015 and 2020 DOE hydrogen storage system cost targets for low and medium power can be achieved using the electrochemical alane synthesis process. To meet the most aggressive 2020 storage system cost target, $1/g, our model indicates that 420 metric tons per year (MT/y) production of alpha-alane is required. Laboratory-scale experimental work demonstrated that the yields of two of the three critical component steps within the overall “electrochemical process” were

  15. Innovations in Los Alamos alpha box design

    International Nuclear Information System (INIS)

    Ledbetter, J.M.; Dowler, K.E.; Cook, J.H.

    1985-01-01

    Destructive examinations of irradiated fuel pins containing plutonium fuel must be performed in shielded hot cells with strict provisions for containing the plutonium. Alpha boxes provide containment for the plutonium, toxic fission products, and other hazardous highly radioactive materials. The alpha box contains windows for viewing and a variety of transfer systems specially designed to allow transfers in and out of the alpha box without spread of the hazardous materials that are contained in the box. Alpha boxes have been in use in the Wing 9 hot cells at Los Alamos National Laboratory for more than 20 years. Features of the newly designed alpha boxes are presented

  16. Space Station alpha joint bearing

    Science.gov (United States)

    Everman, Michael R.; Jones, P. Alan; Spencer, Porter A.

    1987-01-01

    Perhaps the most critical structural system aboard the Space Station is the Solar Alpha Rotary Joint which helps align the power generation system with the sun. The joint must provide structural support and controlled rotation to the outboard transverse booms as well as power and data transfer across the joint. The Solar Alpha Rotary Joint is composed of two transition sections and an integral, large diameter bearing. Alpha joint bearing design presents a particularly interesting problem because of its large size and need for high reliability, stiffness, and on orbit maintability. The discrete roller bearing developed is a novel refinement to cam follower technology. It offers thermal compensation and ease of on-orbit maintenance that are not found in conventional rolling element bearings. How the bearing design evolved is summarized. Driving requirements are reviewed, alternative concepts assessed, and the selected design is described.

  17. Photoionization pathways and thresholds in generation of Lyman-α radiation by resonant four-wave mixing in Kr-Ar mixture

    OpenAIRE

    Oleg A. Louchev; Norihito Saito; Yu Oishi; Koji Miyazaki; Kotaro Okamura; Jumpei Nakamura; Masahiko Iwasaki; Satoshi Wada

    2016-01-01

    We develop a set of analytical approximations for the estimation of the combined effect of various photoionization processes involved in the resonant four-wave mixing generation of ns pulsed Lyman-α (L-α) radiation by using 212.556 nm and 820-845 nm laser radiation pulses in Kr-Ar mixture: (i) multi-photon ionization, (ii) step-wise (2+1)-photon ionization via the resonant 2-photon excitation of Kr followed by 1-photon ionization and (iii) laser-induced avalanche ionization produced by genera...

  18. Development of low level alpha particle counting system

    International Nuclear Information System (INIS)

    Minobe, Masao; Kondo, Hiraku; Chinuki, Takashi; Hirano, Hiromichi

    1987-01-01

    Much attention has been paid to the trace analysis of uranium and thorium contained in the base material of LSI or VLSI, since the so-called ''soft-error'' of the memory device was known to be due to alpha particles emitted from these radioactive elements. We have developed an apparatus to meet the needs of estimating such a very small quantity of U and Th of the level of ppb, by directly counting alpha particles using a gas-flow type proportional counter. This method requires no sophisticated analytical skill, and the accuracy of the result is satisfactory. The instrumentation and some application of this apparatus are described. (author)

  19. Stationary inverted Lyman population formed from incandescently heated hydrogen gas with certain catalysts

    Energy Technology Data Exchange (ETDEWEB)

    Mills, Randell L; Ray, Paresh C; Mayo, Robert M [BlackLight Power, Inc., 493 Old Trenton Road, Cranbury, NJ 08512 (United States)

    2003-07-07

    A new chemically generated plasma source is reported. The presence of gaseous Rb{sup +} or K{sup +} ions with thermally dissociated hydrogen formed a low applied temperature, extremely low voltage plasma called a resonant transfer or rt-plasma having strong vacuum ultraviolet emission. We propose an energetic catalytic reaction involving a resonant energy transfer between hydrogen atoms and Rb{sup +} or 2K{sup +} since Rb{sup +} to Rb{sup 2+}, 2K{sup +} to K + K{sup 2+}, and K to K{sup 3+} each provide a reaction with a net enthalpy equal to the potential energy of atomic hydrogen. Remarkably, a stationary inverted Lyman population was observed; thus, these catalytic reactions may pump a cw HI laser as predicted by a collisional radiative model used to determine that the observed overpopulation was above threshold.

  20. The determination of $\\alpha_s$ by the ALPHA collaboration

    CERN Document Server

    Bruno, Mattia

    2016-01-01

    We review the ALPHA collaboration strategy for obtaining the QCD coupling at high scale. In the three-flavor effective theory it avoids the use of perturbation theory at $\\alpha > 0.2$ and at the same time has the physical scales small compared to the cutoff $1/a$ in all stages of the computation. The result $\\Lambda_\\overline{MS}^{(3)}=332(14)$~MeV is translated to $\\alpha_\\overline{MS}(m_Z)=0.1179(10)(2)$ by use of (high order) perturbative relations between the effective theory couplings at the charm and beauty quark "thresholds". The error of this perturbative step is discussed and estimated as $0.0002$.

  1. Rocket borne solar eclipse experiment to measure the temperature structure of the solar corona via lyman-α line profile observations

    International Nuclear Information System (INIS)

    Argo, H.V.

    1981-01-01

    A rocket borne experiment to measure the temperature structure of the inner solar corona via the doppler broadening of the resonance hydrogen Lyman-α (lambda1216A) radiation scattered by ambient neutral hydrogen atoms was attempted during the 16 Feb 1980 solar eclipse. Two Nike-Black Brant V sounding rockets carrying instrumented payloads were launched into the path of the advancing eclipse umbra from the San Marco satellite launch platform 3 miles off the east coast of Kenya

  2. Polarization Calibration of the Chromospheric Lyman-Alpha SpectroPolarimeter for a 0.1% Polarization Sensitivity in the VUV Range. Part II: In-Flight Calibration

    Czech Academy of Sciences Publication Activity Database

    Giono, G.; Ishikawa, R.; Narukage, N.; Kano, R.; Katsukawa, Y.; Kubo, M.; Ishikawa, S.; Bando, T.; Hara, H.; Suematsu, Y.; Winebarger, A.; Kobayashi, K.; Auchere, F.; Trujillo Bueno, J.; Tsuneta, S.; Shimizu, T.; Sakao, T.; Cirtain, J.; Champey, P.; Asensio Ramos, A.; Štěpán, Jiří; Belluzzi, L.; Sainz, R.M.; de Pontieu, B.; Ichimoto, K.; Carlsson, M.; Casini, R.; Goto, M.

    2017-01-01

    Roč. 292, č. 4 (2017), 57/1-57/19 ISSN 0038-0938 R&D Projects: GA ČR(CZ) GA16-16861S Institutional support: RVO:67985815 Keywords : solar transition region * ly-alpha * magnetohydrodynamic model Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics OBOR OECD: Astronomy (including astrophysics,space science) Impact factor: 2.682, year: 2016

  3. Efficient four-wave mixing by usage of resonances in mercury; Effizientes Vierwellenmischen durch Ausnutzen von Resonanzen in Quecksilber

    Energy Technology Data Exchange (ETDEWEB)

    Kolbe, Daniel

    2011-05-05

    A continuous, coherent radiation source in the vacuum ultraviolet spectral region is presented. It is based on four-wave-mixing in mercury vapor with fundamental beams at 253.7 nm, 407.9 nm und 545.5 nm wavelength. The fundamental beams are produced by frequency doubling and quadrupling of beams from solid-state laser-systems respectively. Due to the 6{sup 1}S-7{sup 1}S two-photon resonance and additionally the 6{sup 1}S-6{sup 3}P one-photon resonance the efficiency can be increased compared to former sources. A near one-photon resonance reduces the optimal phasematching temperature of the four-wave-mixing process. This leads to smaller Doppler and pressure broadening resulting in a higher four-wave-mixing efficiency. A maximum power of 0.3 nW at 121.56 nm wavelength, the 1S-2P Lyman-{alpha} transition in hydrogen, can be obtained. This Lyman-{alpha} source is needed for future laser cooling of antihydrogen. Apart from the Lyman-{alpha} generation, four-wave-mixing with a slightly different third fundamental wavelength results in radiation near a one-photon resonance in the VUV at the 6{sup 1}S-12{sup 1}P transition in mercury. Due to this additional one-photon resonance the nonlinear susceptibility, responsible for the four-wave-mixing, can be strongly increased without an influence on the phasematching. With such a mixing process the efficiency can be enlarged by three orders of magnitude and powers up to 6 {mu}W in the VUV could be realised. This is an improvement of a factor of 30 to former laser sources in this VUV regime. Furthermore the two-photon resonance of mercury could be investigated in detail. We observed a velocity-selective double resonance at small Rabi frequencies of the fundamental beams, which has the same origin as dark resonances in {lambda}-systems. At high Rabi frequencies excitation to the two-photon level can be high enough to initiate a laser process on the 7{sup 1}S-6{sup 1}P transition. This process could be observed with continuouswave

  4. Real-time monitoring for alpha emitters in high-airflow environments

    International Nuclear Information System (INIS)

    Koster, J.E.; MacArthur, D.W.; Bounds, J.A.; Rawool-Sullivan, M.; Whitley, C.R.; Conaway, J.G.; Steadman, P.A.

    1996-01-01

    Key problems in detecting alpha contamination for site characterization and decontamination and decommissioning that remain to be solved include measurement of airborne contamination, material holdup within pipes, and leakage of material containers. These problems are very difficult using traditional alpha detectors and systems. The ionization detection method (long-range alpha detection of LRAD) offers a number of specific advantages for these environmental measurements. An LRAD system detects the air molecules ionized by alpha-emitting contamination rather than the alpha particles. Thus, LRAD-based detectors are not limited by the short range of alpha particles and can be used to detect contamination anywhere that air can penetrate. Extending this technology to large enclosures of long pipes requires a system optimized for large airflows. In this paper we will present designs and preliminary results for high-volume flow-through air monitors based on the LRAD technique. In addition, we will discuss the behavior of the monitors and their potential applications

  5. Alpha decay and various problems related to it

    International Nuclear Information System (INIS)

    Katori, Kenji

    1992-01-01

    On the proton-excessive nucleus side of lanthanide and actinide, alpha decay is the main decay mode. In lanthanide region, alpha decay has been measured to the drip line for most even-even nuclei. In the measurement of alpha decay, emitted energy and life are measured, but the measurement of converted alpha width remains in the limited range. In order to obtain the converted alpha width of high accuracy, the nucleus formation in larger quantity on the drip line and the simultaneous measurement with a multiple detector system including gamma ray and beta ray are required. In this paper, three topics related to alpha cluster and alpha decay and the problems that confront at present are discussed. The continuation to exist of alpha cluster structure to heavy nuclei, the analysis of lanthanide nucleus region by the alpha giant resonance model, and the new data on the alpha ray decaying from the mass of 175, 176 and 177 are reported. In lanthanide nucleus region, remarkable interference was not observed between beta-2 and beta-3 modes in the converted alpha width measured between the ground states. The present problems in alpha decay are enumerated. (K.I.)

  6. [Anti-TNF alpha in dermatology].

    Science.gov (United States)

    Mahe, E; Descamps, V

    2002-12-01

    The discovery of the major role of TNF alpha in the physiopathology of certain inflammatory diseases and notably in rheumatoid arthritis and Crohn's disease has led to the development of anti-TNF alpha drugs. These new therapeutic arms issued from bio-technology have rapidly demonstrated their efficacy in the treatment of these two diseases. The anti-TNF alpha arsenal is currently dominated by etanercept, a fusion protein composed of a soluble TNF alpha receptor, and infliximab, a chimeric monoclonal antibody. However, new molecules will soon enrich this arsenal. TNF alpha is a major cytokine of inflammatory diseases of the skin. Many dermatological diseases will probably benefit from these new treatments. Two studies have already demonstrated their interest in cutaneous and articular psoriasis. Encouraging sporadic results suggest other potential indications (Behcet's disease, bullous dermatitis, neutrophilic dermatitis, toxic epidermal necrolysis, systemic vascularitis,.). These promising new treatments, although expensive, and with yet unknown long term side effects, justify rigorous assessment of their efficacy and tolerance in each indication. Here again the dermatologist has a major role to play in post-marketing pharmacovigilance.

  7. Geocoronal imaging with Dynamics Explorer - A first look

    Science.gov (United States)

    Rairden, R. L.; Frank, L. A.; Craven, J. D.

    1983-01-01

    The ultraviolet photometer of the University of Iowa spin-scan auroral imaging instrumentation on board Dynamics Explorer-1 has returned numerous hydrogen Lyman alpha images of the geocorona from altitudes of 570 km to 23,300 km (1.09 R sub E to 4.66 R sub E geocentric radial distance). The hydrogen density gradient is shown by a plot of the zenith intensities throughout this range, which decrease to near celestial background values as the spacecraft approaches apogee. Characterizing the upper geocorona as optically thin (single-scattering), the zenith intensity is converted directly to vertical column density. This approximation loses its validity deeper in the geocorona, where the hydrogen is demonstrated to be optically thick in that there is no Lyman alpha limb brightening. Further study of the geocoronal hydrogen distribution will require computer modeling of the radiative transfer. Previously announced in STAR as N83-20889

  8. Chromospheric LAyer SpectroPolarimeter (CLASP2)

    Science.gov (United States)

    Narukage, Noriyuki; Cirtain, Jonathan W.; Ishikawa, Ryoko; Trujillo-Bueno, Javier; De Pontieu, Bart; Kubo, Masahito; Ishikawa, Shinnosuke; Kano, Ryohei; Suematsu, Yoshinori; Yoshida, Masaki; hide

    2016-01-01

    The sounding rocket Chromospheric Lyman-Alpha SpectroPolarimeter (CLASP) was launched on September 3rd, 2015, and successfully detected (with a polarization accuracy of 0.1 %) the linear polarization signals (Stokes Q and U) that scattering processes were predicted to produce in the hydrogen Lyman-alpha line (Ly; 121.567 nm). Via the Hanle effect, this unique data set may provide novel information about the magnetic structure and energetics in the upper solar chromosphere. The CLASP instrument was safely recovered without any damage and we have recently proposed to dedicate its second ight to observe the four Stokes profiles in the spectral region of the Mg II h and k lines around 280 nm; in these lines the polarization signals result from scattering processes and the Hanle and Zeeman effects. Here we describe the modifications needed to develop this new instrument called the "Chromospheric LAyer SpectroPolarimeter" (CLASP2).

  9. Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters

    International Nuclear Information System (INIS)

    Garcia, F.; Goncalves, M.; Duarte, S.B.; Tavares, O.A.P.

    2000-02-01

    Alpha-decay half-life for ground-state transitions of 174 even-even alpha emitters has been calculated from a simple, Gamow-like model in which the quadrupole deformation of the product nucleus (assumed to have an ellipsoidal shape) is taken into account. The assumption made is that before tunneling through a purely Coulomb potential barrier the two-body system oscillates isotropically, thus giving rise to an equivalent, average polar direction θ (referred to the symmetry axis of the ellipsoid) for alpha emission. It is shown that the experimental half-life data are much better reproduced by the present description than in the spherical-shaped approximation for the daughter nucleus. (author)

  10. Alpha decay and nuclear deformation: the case for favoured alpha transitions of even-even emitters

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, F. [Universidade Estadual de Santa Cruz, Ilheus, BA (Brazil). Dept. de Ciencias Exatas e Tecnologicas; Rodriguez, O.; Guzman, F. [Instituto Superior de Ciencias y Tecnologia Nucleares (ISCTN), La Habana (Cuba); Goncalves, M. [Instituto de Radioprotecao e Dosimetria IRD/CNEN, Rio de Janeiro, RJ (Brazil); Duarte, S.B.; Tavares, O.A.P. [Centro Brasileiro de Pesquisas Fisicas (CBPF), Rio de Janeiro, RJ (Brazil). E-mail: sbd@cbpf.br

    2000-02-01

    Alpha-decay half-life for ground-state transitions of 174 even-even alpha emitters has been calculated from a simple, Gamow-like model in which the quadrupole deformation of the product nucleus (assumed to have an ellipsoidal shape) is taken into account. The assumption made is that before tunneling through a purely Coulomb potential barrier the two-body system oscillates isotropically, thus giving rise to an equivalent, average polar direction {theta} (referred to the symmetry axis of the ellipsoid) for alpha emission. It is shown that the experimental half-life data are much better reproduced by the present description than in the spherical-shaped approximation for the daughter nucleus. (author)

  11. Differentiation of the mRNA transcripts originating from the alpha 1- and alpha 2-globin loci in normals and alpha-thalassemics.

    OpenAIRE

    Liebhaber, S A; Kan, Y W

    1981-01-01

    The alpha-globin polypeptide is encoded by two adjacent genes, alpha 1 and alpha 2. In the normal diploid state (alpha alpha/alpha alpha) all four alpha-globin genes are expressed. Loss or dysfunction of one or more of these genes leads to deficient alpha-globin production and results in alpha-thalassemia. We present a technique to differentially assess the steady-state levels of the alpha 1- and alpha-2-globin messenger RNA (mRNA) transcripts and thus delineate the relative level of expressi...

  12. Absorber Model: the Halo-like model for the Lyman-α forest

    Science.gov (United States)

    Iršič, Vid; McQuinn, Matthew

    2018-04-01

    We present a semi-analytic model for the Lyman-α forest that is inspired by the Halo Model. This model is built on the absorption line decomposition of the forest. Flux correlations are decomposed into those within each absorption line (the 1-absorber term) and those between separate lines (the 2-absorber term), treating the lines as biased tracers of the underlying matter fluctuations. While the nonlinear exponential mapping between optical depth and flux requires an infinite series of moments to calculate any statistic, we show that this series can be re-summed (truncating at the desired order in the linear matter overdensity). We focus on the z=2–3 line-of-sight power spectrum. Our model finds that 1-absorber term dominates the power on all scales, with most of its contribution coming from H I columns of 1014–1015 cm‑2, while the smaller 2-absorber contribution comes from lower columns that trace overdensities of a few. The prominence of the 1-absorber correlations indicates that the line-of-sight power spectrum is shaped principally by the lines' number densities and their absorption profiles, with correlations between lines contributing to a lesser extent. We present intuitive formulae for the effective optical depth as well as the large-scale limits of 1-absorber and 2-absorber terms, which simplify to integrals over the H I column density distribution with different equivalent-width weightings. With minimalist models for the bias of absorption systems and their peculiar velocity broadening, our model predicts values for the density bias and velocity gradient bias that are consistent with those found in simulations.

  13. Emission of Lyman α radiation in H2 + H*(2s) collisions at thermal energies

    International Nuclear Information System (INIS)

    Stern, B.

    1991-01-01

    A previously-published study of the thermal-energy collision between H 2 and metastable H*(2s), which could lead to the emission of Lyman α radiation, is reconsidered to take into account possible polarization effects. The total was function of the system is expanded in terms of the molecular states of the intermediate complex H 2 * , which constitute the minimal basis of the four adiabatic states dissociating into H 2 + H*(n=2) where they are normally degenerate in energy. The results of the calculation show the existence, between three of those states, of average values of the separation distance R (R ≅ 10 atomic units) of long range (ΔR ≅ 2 au) electronic interactions which depend on the geometric form of the H 2 * molecule. From the molecular data the hypothesis of no longer considering H 2 with H*(2s) as a rigid rotator is postulated and justified, after a purely quantum mechanical treatment of the radial equations. The mean ratio of the (oscillating) polarization angular differential cross sections tot he elastic ones is found important (> ∼ 1/10). The inelastic phenomena are anticipated to be more marked in the ortho than in the para hydrogen at a low collision energy (75 meV). (15 refs., 2 tabs., 9 figs.)

  14. A New Population of High-z, Dusty Lyman-alpha Emitters and Blobs Discovered by WISE: Feedback Caught in the Act?

    Science.gov (United States)

    Bridge, Carrie R.; Blain, Andrew; Borys, Colin J. K.; Petty, Sara; Benford, Dominic; Eisenhardt, Peter; Farrah, Duncan; Griffith, Roger, L.; Jarrett, Tom; Lonsdale, Carol; hide

    2013-01-01

    By combining data from the NASA Wide-field Infrared Survey Explorer (WISE) mission with optical spectroscopy from the W. M. Keck telescope, we discover a mid-IR color criterion that yields a 78% success rate in identifying rare, typically radio-quiet, 1.6 approx. 10(exp 13)-10(exp 14) Solar L) and have warm colors. They are typically more luminous and warmer than other dusty, z approx.. 2 populations such as submillimeter-selected galaxies and dust-obscured galaxies. These traits are commonly associated with the dust being illuminated by intense active galactic nucleus activity. We hypothesize that the combination of spatially extended Ly-alpha, large amounts of warm IR-luminous dust, and rarity (implying a short-lived phase) can be explained if the galaxies are undergoing brief, intense "feedback" transforming them from an extreme dusty starburst/QSO into a mature galaxy.

  15. A pragmatic approach to estimate alpha factors for common cause failure analysis

    International Nuclear Information System (INIS)

    Hassija, Varun; Senthil Kumar, C.; Velusamy, K.

    2014-01-01

    Highlights: • Estimation of coefficients in alpha factor model for common cause analysis. • A derivation of plant specific alpha factors is demonstrated. • We examine sensitivity of common cause contribution to total system failure. • We compare beta factor and alpha factor models for various redundant configurations. • The use of alpha factors is preferable, especially for large redundant systems. - Abstract: Most of the modern technological systems are deployed with high redundancy but still they fail mainly on account of common cause failures (CCF). Various models such as Beta Factor, Multiple Greek Letter, Binomial Failure Rate and Alpha Factor exists for estimation of risk from common cause failures. Amongst all, alpha factor model is considered most suitable for high redundant systems as it arrives at common cause failure probabilities from a set of ratios of failures and the total component failure probability Q T . In the present study, alpha factor model is applied for the assessment of CCF of safety systems deployed at two nuclear power plants. A method to overcome the difficulties in estimation of the coefficients viz., alpha factors in the model, importance of deriving plant specific alpha factors and sensitivity of common cause contribution to the total system failure probability with respect to hazard imposed by various CCF events is highlighted. An approach described in NUREG/CR-5500 is extended in this study to provide more explicit guidance for a statistical approach to derive plant specific coefficients for CCF analysis especially for high redundant systems. The procedure is expected to aid regulators for independent safety assessment

  16. Extracellular overexpression of recombinant Thermobifida fusca cutinase by alpha-hemolysin secretion system in E. coli BL21(DE3

    Directory of Open Access Journals (Sweden)

    Su Lingqia

    2012-01-01

    Full Text Available Abstract Background Extracellular expression of proteins has an absolute advantage in a large-scale industrial production. In our previous study, Thermobifida fusca cutinase, an enzyme mainly utilized in textile industry, was expressed via type II secretory system in Escherichia coli BL21(DE3, and it was found that parts of the expressed protein was accumulated in the periplasmic space. Due to the fact that alpha-hemolysin secretion system can export target proteins directly from cytoplasm across both cell membrane of E. coli to the culture medium, thus in the present study we investigated the expression of cutinase using this alpha-hemolysin secretion system. Results T. fusca cutinase was fused with the specific signal peptide of alpha-hemolysin scretion system and expressed in E. coli BL21(DE3. In addition, HlyB and HlyD, strain-specific translocation components of alpha-hemolysin secretion system, were coexpressed to facilitate the enzyme expression. The cultivation of this engineered cell showed that cutinase activity in the culture medium reached 334 U/ml, which is 2.5 times that from type II secretion pathway under the same culture condition. The recombinant cutinase was further purified. Biochemical characterization of purified enzyme, which had an α-hemolysin secretion pathway signal peptide attached, had substrate specificity, pH and temperature profile, as well as application capability in bioscouring similar to that of wild-type cutinase. Conclusions In the present study, T. fusca cutinase was successfully secreted to the culture media by α-hemolysin secretion system. This is the first report of cutinase being efficiently secreted by this pathway. Due to the limited cases of successful expression of industrial enzyme by E. coli α-hemolysin secretion system, our study further explored the utilization of this pathway in industrial enzymes.

  17. Alternative splicing of T cell receptor (TCR) alpha chain transcripts containing V alpha 1 or V alpha 14 elements.

    Science.gov (United States)

    Mahotka, C; Hansen-Hagge, T E; Bartram, C R

    1995-10-01

    Human acute lymphoblastic leukemia cell lines represent valuable tools to investigate distinct steps of the complex regulatory pathways underlying T cell receptor recombination and expression. A case in point are V delta 2D delta 3 and subsequent V delta 2D delta 3J alpha rearrangements observed in human leukemic pre-B cells as well as in normal lymphopoiesis. The functional expression of these unusual (VD) delta (JC) alpha hybrids is almost exclusively prevented by alternative splicing events. In this report we show that alternative splicing at cryptic splice donor sites within V elements is not a unique feature of hybrid TCR delta/alpha transcripts. Among seven V alpha families analyzed by RT-PCR, alternatively spliced products were observed in TCR alpha recombinations containing V alpha 1 or V alpha 14 elements. In contrast to normal peripheral blood cells and thymocytes, the leukemia cell line JM expressing functional V alpha 1J alpha 3C alpha transcripts lacked evidence of aberrant TCR alpha RNA species.

  18. Effects of x-ray irradiation on the induction of. cap alpha. -amylase synthesis by gibberelic acid in the aleurone system of barley

    Energy Technology Data Exchange (ETDEWEB)

    Zellner, H

    1974-01-01

    The influence of ionizing radiation on a system without DNA replication and cell division was investigated with the aid of GA/sub 3/-induced ..cap alpha..-amylase synthesis in aleurone cells of barley. The reaction of the system was determined by dose effect curves (after irradiation of one half of the endosperms in rest) for the synthesis and secretion of ..cap alpha..-amylase, protein, and reducing sugars. The system proves to be highly radiation-resistant. The course of the synthesis of ..cap alpha..-amylase after X-ray irradiation with varying doses during enzyme synthesis suggests that transcription occurs in the middle of the lag-phase and is the most sensitive stage in enzyme synthesis, while translation alone is less sensitive to radiation.

  19. Molecular Mechanism of AHSP-Mediated Stabilization of Alpha-Hemoglobin

    Energy Technology Data Exchange (ETDEWEB)

    Feng,L.; Gell, D.; Zhou, S.; Gu, L.; Kong, Y.; Li, J.; Hu, M.; Yan, N.; Lee, C.; et al.

    2005-01-01

    Hemoglobin A (HbA), the oxygen delivery system in humans, comprises two alpha and two beta subunits. Free alpha-hemoglobin (alphaHb) is unstable, and its precipitation contributes to the pathophysiology of beta thalassemia. In erythrocytes, the alpha-hemoglobin stabilizing protein (AHSP) binds alphaHb and inhibits its precipitation. The crystal structure of AHSP bound to Fe(II)-alphaHb reveals that AHSP specifically recognizes the G and H helices of alphaHb through a hydrophobic interface that largely recapitulates the alpha1-beta1 interface of hemoglobin. The AHSP-alphaHb interactions are extensive but suboptimal, explaining why beta-hemoglobin can competitively displace AHSP to form HbA. Remarkably, the Fe(II)-heme group in AHSP bound alphaHb is coordinated by the distal but not the proximal histidine. Importantly, binding to AHSP facilitates the conversion of oxy-alphaHb to a deoxygenated, oxidized [Fe(III)], nonreactive form in which all six coordinate positions are occupied. These observations reveal the molecular mechanisms by which AHSP stabilizes free alphaHb.

  20. ALPHA/AMPU, Radionuclide Radioactivity from Alpha Spectrometer Measurements

    International Nuclear Information System (INIS)

    Sill, D.S.

    1990-01-01

    1 - Description of program or function: The two computer programs, ALPHA and AMPU, take raw data obtained from alpha spectrometry and from these calculate activities and uncertainties of the radionuclides present in the sample. ALPHA determines activities of any alpha emitter in a sample that has been directly precipitated with NdF 3 . AMPU determines the Pu-239, Pu-238,and Am-241 activities using Pu-236 and Am-243 tracers. 2 - Method of solution: These programs propagate all random and systematic uncertainties, found anywhere in the experimental process, to the final result. The result is rounded and is in decimal agreement with the uncertainty. 3 - Restrictions on the complexity of the problem: In ALPHA, a chemical yield of 98% is assumed

  1. Resting alpha activity predicts learning ability in alpha neurofeedback

    Directory of Open Access Journals (Sweden)

    Wenya eNan

    2014-07-01

    Full Text Available Individuals differ in their ability to learn how to regulate the alpha activity by neurofeedback. This study aimed to investigate whether the resting alpha activity is related to the learning ability of alpha enhancement in neurofeedback and could be used as a predictor. A total of 25 subjects performed 20 sessions of individualized alpha neurofeedback in order to learn how to enhance activity in the alpha frequency band. The learning ability was assessed by three indices respectively: the training parameter changes between two periods, within a short period and across the whole training time. It was found that the resting alpha amplitude measured before training had significant positive correlations with all learning indices and could be used as a predictor for the learning ability prediction. This finding would help the researchers in not only predicting the training efficacy in individuals but also gaining further insight into the mechanisms of alpha neurofeedback.

  2. Altered TNF-Alpha, Glucose, Insulin and Amino Acids in Islets Langerhans Cultured in a Microgravity Model System

    Science.gov (United States)

    Tobin, Brian W.; Leeper-Woodford, Sandra K.; Hashemi, Brian B.; Smith, Scott M.; Sams, Clarence F.

    2001-01-01

    The present studies were designed to determine effects of a microgravity model system upon lipopolysaccharide (LPS) stimulated tumor necrosis factor alpha (TNF-alpha) activity and indices of insulin and fuel homeostasis of pancreatic islets of Langerhans. Islets (1726+/-1 17,150 u IEU) from Wistar Furth rats were treated as: 1) HARV (High Aspect Ratio Vessel cell culture) , 2) HARV plus LPS, 3) static culture, 4) static culture plus LPS. TNF-alpha (L929 cytotoxicity assay) was significantly increased in LPS-induced HARV and static cultures, yet the increase was more pronounced in the static culture group (palpha production of pancreatic islets of Langerhans, favoring a lesser TNF activity in the HARV. These alterations in fuel homeostasis may be promulgated by gravity averaged cell culture methods or by three dimensional cell assembly.

  3. Reggeon field theory for alpha (0)>1

    CERN Document Server

    Amati, Daniele; Le Bellac, M; Marchesini, G

    1976-01-01

    The asymptotic behaviour of the scattering amplitude is obtained when the pomeron has intercept alpha (0) larger than one. The reggeon field theory is studied by introducing a lattice in impact parameter space. Use is made of a previous result showing that asymptotically the dynamics is controlled at each lattice site ( alpha '=0 case) by a two-level structure. This leads to a non-Hermitean Hamiltonian expressed in terms of spin operators in which the intersite interaction term is proportional to the pomeron slope alpha '. The spectrum of such a system shows a degenerate ground state for alpha (0)> alpha /sub c/>or approximately=1 and a continuum with vanishing excitation gap at alpha (0)= alpha /sub c/. The vacuum does not change structure at the critical value. The criticality is shown by an order parameter which is given by the matrix element of a field operator between the vacuum and its degenerate companion. The nature of this critical phenomenon is better understood by continuously transforming the Hami...

  4. 5 alpha-reductase inhibitors and prostatic disease.

    Science.gov (United States)

    Schröder, F H

    1994-08-01

    5 alpha-Reductase inhibitors are a new class of substances with very specific effects on type I and type II 5 alpha R which may be of use in the treatment of skin disease, such as male pattern baldness, male acne and hirsutism, as well as prostatic hyperplasia and prostate cancer. At least two types of 5 alpha R inhibitors with a different pH optimum have been described. cDNA encoding for both the type I and the type II enzyme has been cloned. Most of the orally effective 5 alpha R inhibitors belong to the class of 4-azasteroids. The radical substituted in the 17 position of the steroid ring seems to be related to species specific variations and to the types of 5 alpha R enzymes in different species and organ systems. 5 alpha R inhibitors lead to a decrease of plasma DHT by about 65% while there is a slight rise in plasma testosterone. The decrease of tissue DHT in the ventral prostate of the intact rat, the dog and in humans is more pronounced and amounts to about 85%. There is a reciprocal rise of tissue T in these systems. The application of an inhibitor of 5 alpha R type II leads to a shrinkage of BPH in men by about 30%. In the rat a similar shrinkage accompanied by a significant decrease of total organ DNA occurs. This decrease, however, is not as pronounced as can be achieved with castration.(ABSTRACT TRUNCATED AT 250 WORDS)

  5. Molecular basis for nondeletion alpha-thalassemia in American blacks. Alpha 2(116GAG----UAG).

    OpenAIRE

    Liebhaber, S A; Coleman, M B; Adams, J G; Cash, F E; Steinberg, M H

    1987-01-01

    An American black woman was found to have the phenotype of moderately severe alpha-thalassemia normally associated with the loss of two to three alpha-globin genes despite an alpha-globin gene map that demonstrated the loss of only a single alpha-globin gene (-alpha/alpha alpha). Several individuals in her kindred with normal alpha-globin gene mapping studies (alpha alpha/alpha alpha) had mild alpha-thalassemia hematologic values consistent with the loss of one to two alpha-globin genes. Thes...

  6. A new scanning system for alpha decay events as calibration sources for range-energy relation in nuclear emulsion

    Science.gov (United States)

    Yoshida, J.; Kinbara, S.; Mishina, A.; Nakazawa, K.; Soe, M. K.; Theint, A. M. M.; Tint, K. T.

    2017-03-01

    A new scanning system named "Vertex picker" has been developed to rapid collect alpha decay events, which are calibration sources for the range-energy relation in nuclear emulsion. A computer-controlled optical microscope scans emulsion layers exhaustively, and a high-speed and high-resolution camera takes their micrographs. A dedicated image processing picks out vertex-like shapes. Practical operations of alpha decay search were demonstrated by emulsion sheets of the KEK-PS E373 experiment. Alpha decays of nearly 28 events were detected in eye-check work on a PC monitor per hour. This yield is nearly 20 times more effective than that by the conventional eye-scan method. The speed and quality is acceptable for the coming new experiment, J-PARC E07.

  7. A new scanning system for alpha decay events as calibration sources for range-energy relation in nuclear emulsion

    International Nuclear Information System (INIS)

    Yoshida, J.; Kinbara, S.; Mishina, A.; Nakazawa, K.; Soe, M.K.; Theint, A.M.M.; Tint, K.T.

    2017-01-01

    A new scanning system named “Vertex picker” has been developed to rapid collect alpha decay events, which are calibration sources for the range-energy relation in nuclear emulsion. A computer-controlled optical microscope scans emulsion layers exhaustively, and a high-speed and high-resolution camera takes their micrographs. A dedicated image processing picks out vertex-like shapes. Practical operations of alpha decay search were demonstrated by emulsion sheets of the KEK-PS E373 experiment. Alpha decays of nearly 28 events were detected in eye-check work on a PC monitor per hour. This yield is nearly 20 times more effective than that by the conventional eye-scan method. The speed and quality is acceptable for the coming new experiment, J-PARC E07.

  8. New evaluation of alpha decay half-life of 190Pt isotope for the Pt-Os dating system

    International Nuclear Information System (INIS)

    Tavares, O.A.P.; Medeiros, E.L.; Terranova, M.L.

    2005-08-01

    A semiempirical model based on the quantum mechanical tunnelling mechanism of alpha emission from nuclei has been used to evaluate the half-life of the Pt isotopes. For the important naturally occurring 190 Pt isotope, the radiogenic parent in the 190 Pt → 186 Os dating system, the model yielded a half-life value of (3.7± 0.3) versus 10 11 y. This is comparable to (3.2±0.1) versus 10 11 y which was obtained in the last direct counting experiment to measure the alpha activity of 190 Pt (Tavares and Terranova, Rad. Measurem. 27 (1997) 19). A literature survey of available alpha decay half-life values for 190 Pt isotope is also reported. The significant discrepancies found between data obtained by direct counting, indirect geological methods and different calculation models are analysed and discussed. (author)

  9. Optimizing BAO measurements with non-linear transformations of the Lyman-α forest

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Xinkang; Font-Ribera, Andreu; Seljak, Uroš, E-mail: xinkang.wang@berkeley.edu, E-mail: afont@lbl.gov, E-mail: useljak@berkeley.edu [Department of Physics, University of California, South Hall Rd, Berkeley (United States)

    2015-04-01

    We explore the effect of applying a non-linear transformation to the Lyman-α forest transmitted flux F=e{sup −τ} and the ability of analytic models to predict the resulting clustering amplitude. Both the large-scale bias of the transformed field (signal) and the amplitude of small scale fluctuations (noise) can be arbitrarily modified, but we were unable to find a transformation that increases significantly the signal-to-noise ratio on large scales using Taylor expansion up to the third order. In particular, however, we achieve a 33% improvement in signal to noise for Gaussianized field in transverse direction. On the other hand, we explore an analytic model for the large-scale biasing of the Lyα forest, and present an extension of this model to describe the biasing of the transformed fields. Using hydrodynamic simulations we show that the model works best to describe the biasing with respect to velocity gradients, but is less successful in predicting the biasing with respect to large-scale density fluctuations, especially for very nonlinear transformations.

  10. Evolution of the intergalactic medium - What happened during the epoch z = 3-10?

    Science.gov (United States)

    Ikeuchi, S.; Ostriker, J. P.

    1986-01-01

    An attempt is made to model consistently the thermal and dynamic history of the intergalactic medium (IGM) from the era of reheating (z = 10-5) to the present, and to provide a unified explanation for the origin of ordinary galaxies, blue compact objects, and Lyman-alpha clouds. The evolution of the intergalactic gas is analyzed, treating the IGM as perfectly homogeneous at every epoch and taking into account radiative and Compton cooling, adiabatic cooling, shock heating, and heating produced by the diffuse UV flux. It is suggested that the IGM must have been heated to higher than a 10 to the 6th K by shock heasting caused either by explosions of pregalactic objects or expanding voids. The formation of intergalactic clouds by fragmentation of the resulting shells and the subsequent collapse of the shells to form galaxies are studied. An attempt is made to determine model parameters on the basis of an analysis of Lyman-alpha absorption lines.

  11. Was Proxima captured by Alpha Centauri A and B?

    Science.gov (United States)

    Feng, F.; Jones, H. R. A.

    2018-01-01

    The nearest stellar system consists of the stars Proxima, Alpha Centauri A and B and at least one planet Proxima b. The habitability of Proxima b and any other planets are likely to be significantly influenced by the orbital evolution of the system. To study the dynamical evolution of the system, we simulate the motions of Proxima and Alpha Centauri A and B due to the perturbations from the Galactic tide and stellar encounters in a Monte Carlo fashion. From 100 clones, we find that 74 per cent orbits of Proxima Centauri are bound to Alpha Centauri A and B while 17 per cent and 9 per cent orbits become unbound in the simulations over the past and future 5 Gyr. If the system migrated outward in the Milky Way to its current location, more than 50 per cent of clones could become unstable in backward simulations. The ratio of unstable clones increases with the simulation time-scale and encounter rate. This provides some evidence for a capture scenario for the formation of the current triple system. Despite large uncertainties, the metallicity difference between Proxima and Alpha Centauri A and B is also suggestive of their different origin. None the less, further improvements in the available data and models will be necessary for a reliable assessment of the history of the Proxima-Alpha Centauri system and its impact on the habitability of Proxima b.

  12. Lyman NTCP model analysis of radiation-induced liver disease in hypofractionated conformal radiotherapy for primary liver carcinoma

    International Nuclear Information System (INIS)

    Xu Zhiyong; Zhu Yi; Zhao Jiaodong; Fu Xiaolong; Jiang Guoliang; Liang Shixiong; Zhu Xiaodong

    2006-01-01

    Objective: To identify the factors associated with radiation-induced liver disease (RILD) and to describe the probability of RILD using the Lyman normal tissue complication(NTCP) model for primary liver carcinoma(PLC) treated with hypofractionated conformal therapy (CRT). Methods: A total of 109 PLC patients treated with hypofractionated CRT were prospectively followed according to the Child-Pugh classification for liver cirrhosis, 93 patients in class A and 16 in class B. The mean dose of radiation to the isocenter was (53.5±5.5) Gy, fractions of (4.8±0.5) Gy, with interfraction interval of 48 hours and irradiation 3 times per week. Maximal likelihood analysis yielded the best estimates of parameters of the Lyman NTCP model for all patients; Child-Pugh A and Child-Pugh B patients, respectively. Results: Of all the patients, 17 developed RILD (17/109), 8 in Child-Pugh A (8/93) and 9 in Child-Pugh B (9/16). By multivariate analysis, only the Child-Pugh Grade of liver cirrhosis was the independent factor (P=0.000) associated with the developing of BILD. The best estimates of the NTCP parameters for all 109 patients were n=1.1, m=0.35 and TD 50 (1)=38.5 Gy. The n, m, TD 50 (1) estimated from patients with Child-Pugh A was 1.1, 0.28, 40.5 Gy, respectively, compared with 0.7, 0.43, 23 Gy respectively, for patients with Child-Pugh B. Conclusions: Primary liver cancer patients who possess Child-Pugh B cirrhosis would present a significantly greater susceptibility to RILD after hypofractionated CRT than patients with Child-Pugh A cirrhosis. The predominant risk factor for developing RILD is the severity of hepatic cirrhosis in the liver of PLC patients. (authors)

  13. Anti-pp,. cap alpha cap alpha. and p. cap alpha. elastic scattering at high energies and Chou-Yang conjecture

    Energy Technology Data Exchange (ETDEWEB)

    Saleem, M.; Fazal-e-Aleem; Rifique, M.

    1987-03-01

    The recent experimental measurements for anti-pp and ..cap alpha cap alpha.. elastic scattering at high energies have shown that the Chou-Yang conjecture regarding the relationship between the electromagnetic and the hadronic form factor of a particle is only an approximation. A new ansatz has been proposed to obtain hadronic form factors of proton and the ..cap alpha..-particle. These form factors have been used to explain the various characteristics of anti-pp, ..cap alpha cap alpha.. and p..cap alpha.. elastic scattering at high energies.

  14. Developmental changes in the role of a pertussis toxin sensitive guanine nucleotide binding protein in the rat cardiac alpha1-adrenergic system

    International Nuclear Information System (INIS)

    Han, H.M.

    1989-01-01

    During development, the cardiac alpha 1 -adrenergic chronotropic response changes from positive in the neonate to negative in the adult. This thesis examined the possibility of a developmental change in coupling of a PT-sensitive G-protein to the alpha 1 -adrenergic receptor. Radioligand binding experiments performed with the iodinated alpha 1 -selective radioligand [ 125 I]-I-2-[β-(4-hydroxphenyl)ethylaminomethyl]tetralone ([ 125 I]-IBE 2254) demonstrated that the alpha 1 -adrenergic receptor is coupled to a G-protein in both neonatal and adult rat hearts. However, in the neonate the alpha 1 -adrenergic receptor is coupled to a PT-insensitive G-protein, whereas in the adult the alpha 1 -adrenergic receptor is coupled to both a PT-insensitive and a PT-sensitive G-protein. Consistent with the results from binding experiments, PT did not have any effect on the alpha 1 -mediated positive chronotropic response in the neonate, whereas in the adult the alpha 1 -mediated negative chronotropic response was completely converted to a positive one after PT-treatment. This thesis also examined the possibility of an alteration in coupling of the alpha 1 -adrenergic receptor to its effector under certain circumstances such as high potassium (K + ) depolarization in nerve-muscle (NM) co-cultures, a system which has been previously shown to be a convenient in vitro model to study the mature inhibitory alpha 1 -response

  15. Operating program for an automatic alpha-beta counting system-FAG

    Energy Technology Data Exchange (ETDEWEB)

    German, U; Levinson, L; Shemesh, Y; Peled, O; Weistein, M [Israel Atomic Energy Commission, Beersheba (Israel). Nuclear Research Center-Negev

    1996-12-01

    An alpha and beta counting system - FAG, for planchette samples is operated at the Health Physics department`s laboratory of the NRCN. The system consists of a proportional detector of 8`` diameter operated in coincidence with a guard detector, an automatic sample changer (FAG-FHT770E) and electronics (FAG- FHT1100 digital counter and controller). The original operation mode of the system was based on manual tasks handled by the FHT1100 electronics. Pin option for a basic computer keyboard operation was available too. A computer with appropriate 110 card was connected to the system and a new operating program was developed which enables full automatic control of the various components. The program includes activity calculations and statistical checks as well as data management. The program which was developed enables computer control of all components of the system, based on bi-directional communication. The computer software controls the FHT1100 electronics using the R5232 protocol and the sample changer by an additional 110 card Contec Inodel PIO-48W(PC). The computer controls the whole operation of the system: change of samples, high voltage change, start, stop etc. It handles in the appropriate order the different commands and operates the electronic and mechanic components accordingly (authors).

  16. Operating program for an automatic alpha-beta counting system-FAG

    International Nuclear Information System (INIS)

    German, U.; Levinson, L.; Shemesh, Y.; Peled, O.; Weistein, M.

    1996-01-01

    An alpha and beta counting system - FAG, for planchette samples is operated at the Health Physics department's laboratory of the NRCN. The system consists of a proportional detector of 8'' diameter operated in coincidence with a guard detector, an automatic sample changer (FAG-FHT770E) and electronics (FAG- FHT1100 digital counter and controller). The original operation mode of the system was based on manual tasks handled by the FHT1100 electronics. Pin option for a basic computer keyboard operation was available too. A computer with appropriate 110 card was connected to the system and a new operating program was developed which enables full automatic control of the various components. The program includes activity calculations and statistical checks as well as data management. The program which was developed enables computer control of all components of the system, based on bi-directional communication. The computer software controls the FHT1100 electronics using the R5232 protocol and the sample changer by an additional 110 card Contec Inodel PIO-48W(PC). The computer controls the whole operation of the system: change of samples, high voltage change, start, stop etc. It handles in the appropriate order the different commands and operates the electronic and mechanic components accordingly (authors)

  17. Activity monitoring of alpha-bearing wastes

    International Nuclear Information System (INIS)

    Birkhoff, G.; Bondar, L.

    1980-01-01

    The paper aims at the survey on the actual situation in activity monitoring of alpha-bearing wastes. Homogeneous materials such as liquid-, gaseous- and homogeneous solid wastes are amenable to destructive analyses of representative samples. Available destructive analyses methods are sensitive and precise enough to cope with all requirements in alpha-waste monitoring. The more difficult problems are encountered with alpha-contaminated solids, when representative sampling is not practicable. Non-destructive analysis techniques are applied for monitoring this category of solid wastes. The techniques for nondestructive analysis of alpha-bearing wastes are based on the detection of gamma and/or neutron-emission of actinides. Principles and a theory of non-destructive radiometric assay of plutonium contaminated solid waste streams are explained. Guidelines for the calibration of instruments and interpretation of experimental data are given. Current theoretical and experimental development work in this problem area is reviewed. Evaluations concerning capabilities and limitations of monitoring systems for alpha-bearing solid wastes are very complex and out of the scope of this paper

  18. Contribution to the study of alpha-alpha interaction; Contribution a l'etude de l'interaction alpha - alpha

    Energy Technology Data Exchange (ETDEWEB)

    Darriulai, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1965-03-01

    Two sets of measurements of the {alpha}-{alpha} elastic scattering differential cross section are presented. The first set - angular distributions from 50 up to 120 MeV - shows two new resonances, 6{sup +} and 8{sup +}, at 25 and 57 MeV. Complex phase shifts are extracted from the data and a phenomenological potential is given. A description of the 3 {alpha}-particle 0{sup +} states in C{sup 12} is made with this interaction potential. The second set - excitation curves between 20 and 50 MeV - allows investigation of the Be{sup 8} level structure within this energy range - It identifies the 16.6 and 16.9 MeV states as 2{sup +}, but the rise of inelastic processes at higher energies makes further identification of spins and parities more and more difficult. (author) [French] Deux series de mesures de la section efficace differentielle de diffusion {alpha}-{alpha} sont presentees. La premiere - distributions angulaires entre 50 et 120 MeV - fait apparaitre deux nouvelles resonances, 6{sup +} et 8{sup +}, a 25 et 57 MeV d'excitation. Des dephasages complexes en sont extraits et un potentiel phenomenologique est presente. Une etude des etats 0{sup +} a parentage (3{alpha}) de {sup 12}C est faite a partir de ce potentiel. La seconde - courbes d'excitation s'etendant de 20 a 50 MeV - met en evidence la structure de {sup 8}Be dans cette region. Elle montre que les niveaux a 16,6 et 16,9 MeV sont des 2{sup +} mais l'importance des processus inelastiques rend difficile l'identification des niveaux d'excitation plus elevee. (auteur)

  19. Fitting methods for baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

    Energy Technology Data Exchange (ETDEWEB)

    Kirkby, David; Margala, Daniel; Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, 92697 (United States); Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton NY 11375 (United States); Bailey, Stephen; Carithers, Bill [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Busca, Nicolás G.; Bautista, Julian E. [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Delubac, Timothée; Rich, James; Palanque-Delabrouille, Nathalie [CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette (France); Brownstein, Joel R.; Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Croft, Rupert A.C. [Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Font-Ribera, Andreu [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); Miralda-Escudé, Jordi [Institució Catalana de Recerca i Estudis Avançats, Barcelona, Catalonia (Spain); Myers, Adam D. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82071 (United States); Nichol, Robert C. [Institute of Cosmology and Gravitation, Dennis Sciama Building, University of Portsmouth, Portsmouth, PO1 3FX (United Kingdom); Pâris, Isabelle; Petitjean, Patrick, E-mail: dkirkby@uci.edu [Université Paris 6 et CNRS, Institut d' Astrophysique de Paris, 98bis blvd. Arago, 75014 Paris (France); and others

    2013-03-01

    We describe fitting methods developed to analyze fluctuations in the Lyman-α forest and measure the parameters of baryon acoustic oscillations (BAO). We apply our methods to BOSS Data Release 9. Our method is based on models of the three-dimensional correlation function in physical coordinate space, and includes the effects of redshift-space distortions, anisotropic non-linear broadening, and broadband distortions. We allow for independent scale factors along and perpendicular to the line of sight to minimize the dependence on our assumed fiducial cosmology and to obtain separate measurements of the BAO angular and relative velocity scales. Our fitting software and the input files needed to reproduce our main BOSS Data Release 9 results are publicly available.

  20. Diagnostics of MCF plasmas using Lyman-α fluorescence excited by one or two photons

    International Nuclear Information System (INIS)

    Voslamber, D.

    1998-11-01

    Laser-induced Lyman-α fluorescence of the hydrogen isotopes is investigated with regard to diagnostic applications in magnetically confined fusion plasmas. A formal analysis is presented for two excitation schemes: one-photon and Doppler-free two-photon excitation. The analysis includes estimates of the expected experimental errors arising from the photon noise and from the sensitivity of the observed fluorescence signals to variations of the plasma and laser parameters. Both excitation schemes are suitable primarily for application in the plasma edge, but even in the plasma bulk of large machines they can still be applied in combination with a diagnostic neutral beam. The two-photon excitation scheme is particularly attractive because it involves absorption spectra that are resolved within the Doppler width. This implies a large diagnostic potential and in particular offers a way to measure the deuterium-tritium fuel mix in fusion reactors. (author)

  1. High-Reflectivity Multi-Layer Coatings for the CLASP Sounding Rocket Project

    Science.gov (United States)

    Narukage, Noriyuki; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Kubo, Masahito; Katsukawa, Yukio; Ishikawa, Shin-nosuke; Kobiki, Toshihiko; Giono, Gabriel; Auchere, Frederic; hide

    2015-01-01

    We are planning an international rocket experiment Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) is (2015 planned) that Lyman alpha line (Ly alpha line) polarization spectroscopic observations from the sun. The purpose of this experiment, detected with high accuracy of the linear polarization of the Ly alpha lines to 0.1% by using a Hanle effect is to measure the magnetic field of the chromosphere-transition layer directly. For polarization photometric accuracy achieved that approximately 0.1% required for CLASP, it is necessary to realize the monitoring device with a high throughput. On the other hand, Ly alpha line (vacuum ultraviolet rays) have a sensitive characteristics that is absorbed by the material. We therefore set the optical system of the reflection system (transmission only the wavelength plate), each of the mirrors, subjected to high efficiency of the multilayer coating in accordance with the role. Primary mirror diameter of CLASP is about 30 cm, the amount of heat about 30,000 J is about 5 minutes of observation time is coming mainly in the visible light to the telescope. In addition, total flux of the sun visible light overwhelmingly large and about 200 000 times the Ly alpha line wavelength region. Therefore, in terms of thermal management and 0.1% of the photometric measurement accuracy achieved telescope, elimination of the visible light is essential. We therefore, has a high reflectivity (greater than 50%) in Ly alpha line, visible light is a multilayer coating be kept to a low reflectance (less than 5%) (cold mirror coating) was applied to the primary mirror. On the other hand, the efficiency of the polarization analyzer required chromospheric magnetic field measurement (the amount of light) Conventional (magnesium fluoride has long been known as a material for vacuum ultraviolet (MgF2) manufactured ellipsometer; Rs = 22%) about increased to 2.5 times were high efficiency reflective polarizing element analysis. This device, Bridou et al

  2. Investigation of the Pygmy Dipole Resonance in (alpha, alpha 'gamma) coincidence experiments

    NARCIS (Netherlands)

    Savran, D.; Babilon, M.; van den Berg, A. M.; Harakeh, M. N.; Hasper, J.; Wortche, H. J.; Zilges, A.

    2007-01-01

    We report on first results from experiments using the (alpha, alpha'gamma) reaction at E alpha = 136 MeV to investigate bound electric dipole (El) excitations building the so-called Pygmy Dipole Resonance (PDR) in the semi-magic nucleus Ce-140. The method of (alpha, alpha'gamma) allows the

  3. Haro 11: Where is the Lyman Continuum Source?

    Energy Technology Data Exchange (ETDEWEB)

    Keenan, Ryan P.; Oey, M. S. [Department of Astronomy, University of Michigan, 1085 South University Avenue, Ann Arbor, MI 48109 (United States); Jaskot, Anne E. [Department of Astronomy, Smith College, Northampton, MA 01063 (United States); James, Bethan L. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States)

    2017-10-10

    Identifying the mechanism by which high-energy Lyman continuum (LyC) photons escaped from early galaxies is one of the most pressing questions in cosmic evolution. Haro 11 is the best known local LyC-leaking galaxy, providing an important opportunity to test our understanding of LyC escape. The observed LyC emission in this galaxy presumably originates from one of the three bright, photoionizing knots known as A, B, and C. It is known that Knot C has strong Ly α emission, and Knot B hosts an unusually bright ultraluminous X-ray source, which may be a low-luminosity active galactic nucleus. To clarify the LyC source, we carry out ionization-parameter mapping (IPM) by obtaining narrow-band imaging from the Hubble Space Telescope WFC3 and ACS cameras to construct spatially resolved ratio maps of [O iii]/[O ii] emission from the galaxy. IPM traces the ionization structure of the interstellar medium and allows us to identify optically thin regions. To optimize the continuum subtraction, we introduce a new method for determining the best continuum scale factor derived from the mode of the continuum-subtracted, image flux distribution. We find no conclusive evidence of LyC escape from Knots B or C, but instead we identify a high-ionization region extending over at least 1 kpc from Knot A. This knot shows evidence of an extremely young age (≲1 Myr), perhaps containing very massive stars (>100 M {sub ⊙}). It is weak in Ly α , so if it is confirmed as the LyC source, our results imply that LyC emission may be independent of Ly α emission.

  4. Enteric alpha defensins in norm and pathology

    Directory of Open Access Journals (Sweden)

    Lisitsyn Nikolai A

    2012-01-01

    Full Text Available Abstract Microbes living in the mammalian gut exist in constant contact with immunity system that prevents infection and maintains homeostasis. Enteric alpha defensins play an important role in regulation of bacterial colonization of the gut, as well as in activation of pro- and anti-inflammatory responses of the adaptive immune system cells in lamina propria. This review summarizes currently available data on functions of mammalian enteric alpha defensins in the immune defense and changes in their secretion in intestinal inflammatory diseases and cancer.

  5. Review of measurement techniques for stack monitoring of long-lived alpha emitters

    International Nuclear Information System (INIS)

    Kordas, J.F.; Phelps, P.L.

    1978-01-01

    As a result of the promulgation of new guidelines by the Environmental Protection Agency (40 CFR 190) for releases of long-lived, alpha-emitting substances, the stack-monitoring requirements for measuring long-lived alpha particles may change in terms of both monitored isotopes and the detection levels. This paper briefly reviews stack-monitoring requirements for long-lived alpha-emitting particles. It also examines the currently deployed alpha-particulate, stack-monitoring systems and discusses prototype systems that may be applicable to stack monitoring

  6. Study of transfer reactions ({alpha},t), ({alpha},{sup 3}He) in the f-p shell: mechanism and spectroscopic use; Etude des reactions de transfert ({alpha},t), ({alpha},{sup 3}He) dans la couche f-p mecanisme et utilisation spectroscopique

    Energy Technology Data Exchange (ETDEWEB)

    Roussel, P [Commissariat a l' Energie Atomique, Saclay (France). Centre d' Etudes Nucleaires

    1968-05-01

    We describe an experimental study of ({alpha},t), ({alpha},{sup 3}He) reactions at 44 MeV using a solid-state identifier, on the target-nuclei {sup 54}Fe and {sup 58,60,62,64}Ni. A critical study of optical model and of disturbed wave analysis has been performed. We show the complementarity of different transfer-reactions, the ambiguity of spectroscopic factors, the importance of the problem of the reaction mechanism. (author) [French] On decrit une etude experimentale des reactions ({alpha},t), ({alpha},{sup 3}He) a 44 MeV utilisant un systeme identificateur de particules sur les noyaux-cibles {sup 54}Fe et {sup 58,60,62,64}Ni. Une etude critique de modele optique et d'analyse en ondes deformees (D.W.B.A.) a ete entreprise. On montre la complementarite des differentes reactions de transfert, l'ambiguite des facteurs spectroscopiques, l'importance du probleme du mecanisme. (auteur)

  7. Measurement of baryon acoustic oscillations in the Lyman-α forest fluctuations in BOSS data release 9

    Energy Technology Data Exchange (ETDEWEB)

    Slosar, Anže [Brookhaven National Laboratory, Blgd 510, Upton NY 11375 (United States); Iršič, Vid [Faculty of Mathematics and Physics, University of Ljubljana, Jadranska 19, 1000 Ljubljana (Slovenia); Kirkby, David; Blomqvist, Michael [Department of Physics and Astronomy, University of California, Irvine, CA 92697 (United States); Bailey, Stephen; Carithers, Bill [Lawrence Berkeley National Laboratory, 1 Cyclotron Road, Berkeley, CA 94720 (United States); Busca, Nicolás G.; Aubourg, Éric; Bautista, Julian E. [APC, Université Paris Diderot-Paris 7, CNRS/IN2P3, CEA, Observatoire de Paris, 10, rue A. Domon and L. Duquet, Paris (France); Delubac, Timothée; Rich, James; Goff, J.-M. Le [CEA, Centre de Saclay, IRFU, F-91191 Gif-sur-Yvette (France); Bhardwaj, Vaishali [Department of Astronomy, University of Washington, Box 351580, Seattle, WA 09195 (United States); Bolton, Adam S.; Brownstein, Joel; Dawson, Kyle S. [Department of Physics and Astronomy, University of Utah, 115 S 1400 E, Salt Lake City, UT 84112 (United States); Bovy, Jo [Institute for Advanced Study, Einstein Drive, Princeton, NJ 08540 (United States); Croft, Rupert A.C.; Ho, Shirley [Bruce and Astrid McWilliams Center for Cosmology, Carnegie Mellon University, Pittsburgh, PA 15213 (United States); Font-Ribera, Andreu, E-mail: anze@bnl.gov [Institute of Theoretical Physics, University of Zurich, 8057 Zurich (Switzerland); and others

    2013-04-01

    We use the Baryon Oscillation Spectroscopic Survey (BOSS) Data Release 9 (DR9) to detect and measure the position of the Baryonic Acoustic Oscillation (BAO) feature in the three-dimensional correlation function in the Lyman-α flux fluctuations at a redshift z{sub eff} = 2.4. The feature is clearly detected at significance between 3 and 5 sigma (depending on the broadband model and method of error covariance matrix estimation) and is consistent with predictions of the standard ΛCDM model. We assess the biases in our method, stability of the error covariance matrix and possible systematic effects. We fit the resulting correlation function with several models that decouple the broadband and acoustic scale information. For an isotropic dilation factor, we measure 100 × (α{sub iso} − 1) = −1.6{sup +2.0+4.3+7.4}{sub −2.0−4.1−6.8} (stat.) ±1.0 (syst.) (multiple statistical errors denote 1,2 and 3 sigma confidence limits) with respect to the acoustic scale in the fiducial cosmological model (flat ΛCDM with Ω{sub m} = 0.27, h = 0.7). When fitting separately for the radial and transversal dilation factors we find marginalised constraints 100 × (α{sub ||} − 1) = −1.3{sup +3.5+7.6+12.3}{sub −3.3−6.7−10.2} (stat.) ±2.0 (syst.) and 100 × (α{sub p}erpendicular − 1) = −2.2{sup +7.4+17}{sub −7.1−15} (stat.) ±3.0 (syst.). The dilation factor measurements are significantly correlated with cross-correlation coefficient of ∼ −0.55. Errors become significantly non-Gaussian for deviations over 3 standard deviations from best fit value. Because of the data cuts and analysis method, these measurements give tighter constraints than a previous BAO analysis of the BOSS DR9 Lyman-α sample, providing an important consistency test of the standard cosmological model in a new redshift regime.

  8. Physical and morphological properties of z ~ 3 Lyman break galaxies: dependence on Lyα line emission

    Science.gov (United States)

    Pentericci, L.; Grazian, A.; Scarlata, C.; Fontana, A.; Castellano, M.; Giallongo, E.; Vanzella, E.

    2010-05-01

    Aims: We investigate the physical and morphological properties of Lyman break galaxies (LBGs) at redshift ~2.5 to ~3.5, to determine if and how they depend on the nature and strength of the Lyα emission. Methods: We selected U-dropout galaxies from the z-detected GOODS-MUSIC catalog by adapting the classical Lyman break criteria on the GOODS filter set. We kept only those galaxies with spectroscopic confirmation, mainly from VIMOS and FORS public observations. Using the full multi-wavelength 14-bands information (U to IRAC), we determined the physical properties of the galaxies through a standard spectral energy distribution fitting procedure with the updated Charlot & Bruzual (2009) templates. We also added other relevant observations of the GOODS field, i.e. the 24 μm observations from Spitzer/MIPS and the 2 MSec Chandra X-ray observations. Finally, using non parametric diagnostics (Gini, Concentration, Asymmetry, M20 and ellipticity), we characterized the rest-frame UV morphologies of the galaxies. We then analyzed how these physical and morphological properties correlate with the presence of the Lyα emission line in the optical spectra. Results: We find that unlike at higher redshift, the dependence of physical properties on the Lyα line is milder: galaxies without Lyα in emission tend to be more massive and dustier than the rest of the sample, but all other parameters, ages, star formation rates (SFR), X-ray emission and UV morphology do not depend strongly on the presence of the Lyα emission. A simple scenario where all LBGs have intrinsically high Lyα emission, but where the dust and neutral hydrogen content (which shapes the final appearance of the Lyα) depend on the mass of the galaxies, is able to reproduce the majority of the observed properties at z˜3. Some modification might be needed to account for the observed evolution of these properties with cosmic epoch, which is also discussed.

  9. Synthesis and antimicrobial evaluation of new 3-alkyl/aryl-2-[((alpha,alpha-diphenyl-alpha-hydroxy)acetyl)hydrazono]-5-methyl-4-thiazolidinones.

    Science.gov (United States)

    Güzeldemirci, Nuray Ulusoy; Ilhan, Eser; Küçükbasmaci, Omer; Satana, Dilek

    2010-01-01

    New 4-thiazolidinone derivatives of benzilic acid (alpha,alpha-diphenyl-alpha-hydroxyacetic acid) have been synthesized and evaluated for antibacterial and antifungal activities. The reaction of 1- (alpha,alpha-diphenyl-alpha-hydroxy)acetyl-4-alkyl/arylthiosemicarbazides with ethyl 2-bromopropionate gave 3-alkyl/aryl-2-[((alpha,alpha-diphenyl-alpha-hydroxy)acetyl)hydrazono]-5-methyl-4-thiazolidinone derivatives. Their antibacterial and antifungal activities were evaluated against S. aureus ATCC 29213, P. aeruginosa ATCC 27853, E. coli ATCC 25922, C. albicans ATCC 10231, C. parapsilosis ATCC 22019, C. krusei ATCC 6258, T. mentagrophytes var. erinacei NCPF 375, M. gypseum NCPF 580 and T. tonsurans NCPF 245. 3e, 3f, 3g and 3h showed the highest antibacterial activity. Particularly 3a and 3e showed the highest antifungal activities against C. parapsilosis ATCC 22019, T. tonsurans NCPF 245 and M. gypseum NCPF 580.

  10. The Cosmic Dawn and Epoch of Reionisation with SKA

    NARCIS (Netherlands)

    Koopmans, L.; Pritchard, J.; Mellema, G.; Aguirre, J.; Ahn, K.; Barkana, R.; van Bemmel, I.; Bernardi, G.; Bonaldi, A.; Briggs, F.; de Bruyn, A. G.; Chang, T. C.; Chapman, E.; Chen, X.; Ciardi, B.; Dayal, P.; Ferrara, A.; Fialkov, A.; Fiore, F.; Ichiki, K.; Illiev, I. T.; Inoue, S.; Jelic, V.; Jones, M.; Lazio, J.; Maio, U.; Majumdar, S.; Mack, K. J.; Mesinger, A.; Morales, M. F.; Parsons, A.; Pen, U. L.; Santos, M.; Schneider, R.; Semelin, B.; de Souza, R. S.; Subrahmanyan, R.; Takeuchi, T.; Vedantham, H.; Wagg, J.; Webster, R.; Wyithe, S.; Datta, K. K.; Trott, C.

    2014-01-01

    Concerted effort is currently ongoing to open up the Epoch of Reionization (EoR) ($z\\sim$15-6) for studies with IR and radio telescopes. Whereas IR detections have been made of sources (Lyman-$\\alpha$ emitters, quasars and drop-outs) in this redshift regime in relatively small fields of view, no

  11. The Cosmic Dawn and Epoch of Reionisation with SKA

    NARCIS (Netherlands)

    Koopmans, L.; Pritchard, J.; Mellema, G.; Aguirre, J.; Ahn, K.; Barkana, R.; van Bemmel, I.; Bernardi, G.; Bonaldi, A.; Briggs, F.; de Bruyn, A. G.; Chang, T. C.; Chapman, E.; Chen, X.; Ciardi, B.; Dayal, P.; Ferrara, A.; Fialkov, A.; Fiore, F.; Ichiki, K.; Illiev, I. T.; Inoue, S.; Jelic, V.; Jones, M.; Lazio, J.; Maio, U.; Majumdar, S.; Mack, K. J.; Mesinger, A.; Morales, M. F.; Parsons, A.; Pen, U. L.; Santos, M.; Schneider, R.; Semelin, B.; de Souza, R. S.; Subrahmanyan, R.; Takeuchi, T.; Vedantham, H.; Wagg, J.; Webster, R.; Wyithe, S.; Datta, K. K.; Trott, C.

    2015-01-01

    Concerted effort is currently ongoing to open up the Epoch of Reionization (EoR) ($z\\sim$15-6) for studies with IR and radio telescopes. Whereas IR detections have been made of sources (Lyman-$\\alpha$ emitters, quasars and drop-outs) in this redshift regime in relatively small fields of view, no

  12. Design of a preamplifier for an alpha particles spectrometer

    International Nuclear Information System (INIS)

    Murillo O, R.; Hernandez D, V. M.; Chacon R, A.; Vega C, H. R.

    2010-09-01

    To detect radiation diverse detector types are used, when these are alpha particles proportional type detectors are used, semiconductor, of scintillation or traces. In this work the design results, the construction and the first tests of a spectrometer (preamplifier) are presented for alpha particles that was designed starting from a Pin type photodiode. The system was designed and simulated with a program for electronic circuits. With the results of the simulation phase was constructed the electronics that is coupled to a spectroscopic amplifier and a multichannel analyzer. The total of the system is evaluated analyzing its performance before a triple source of alphas and that they are produced by two smoke detectors of domestic use. Of the tests phase we find that the system allows to obtain in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  13. Alpha-tocopheryl phosphate: a novel, natural form of vitamin E.

    Science.gov (United States)

    Gianello, Robert; Libinaki, Roksan; Azzi, Angelo; Gavin, Paul D; Negis, Yesim; Zingg, Jean-Marc; Holt, Phillip; Keah, Hooi-Hong; Griffey, Annike; Smallridge, Andrew; West, Simon M; Ogru, Esra

    2005-10-01

    We have detected alpha-tocopheryl phosphate in biological tissues including liver and adipose tissue, as well as in a variety of foods, suggesting a ubiquitous presence in animal and plant tissue. Alpha-tocopheryl phosphate is a water-soluble molecule that is resistant to both acid and alkaline hydrolysis, making it undetectable using standard assays for vitamin E. A new method was therefore developed to allow the extraction of both alpha-tocopheryl phosphate and alpha-tocopherol from a single specimen. We used ESMS to detect endogenous alpha-tocopheryl phosphate in biological samples that also contained alpha-tocopherol. Due to the significance of these findings, further proof was required to unequivocally demonstrate the presence of endogenous alpha-tocopheryl phosphate in biological samples. Four independent methods of analysis were examined: HPLC, LCMS, LCMS/MS, and GCMS. Alpha-tocopherol phosphate was identified in all instances by comparison between standard alpha-tocopheryl phosphate and extracts of biological tissues. The results show that alpha-tocopheryl phosphate is a natural form of vitamin E. The discovery of endogenous alpha-tocopheryl phosphate has implications for the expanding knowledge of the roles of alpha-tocopherol in biological systems.

  14. Alpha particle radiography of small insects

    International Nuclear Information System (INIS)

    Chingshen Su

    1993-01-01

    Radiographies of ants, mosquitoes, cockroaches and small bugs have been done with a radioisotope 244 Cm alpha source. Energy of alpha particles was varied by attenuating the 5.81 MeV alpha particles with adjustable air spacings from the source to the sample. The LR-115 was used to register radiographs. The image of the insect registered on the LR-115 was etched out in a 2.5 N NaOH solution at 52 o C for certain minutes, depending on various irradiation conditions for the insects. For larger insects, a scanning device for the alpha particle irradiation has been fabricated to take the radiograph of whole body of the insect, and the scanning period can be selected to give desired irradiation dosage. A CCDTV camera system connected to a microscope interfaced to an IBM/AT computer is used to register the microscopic image of the radiograph and to print it out with a video copy processor. (Author)

  15. Evolution in the Continuum Morphological Properties of Ly alpha-Emitting Galaxies from Z=3.1 to Z=2.1

    Science.gov (United States)

    Bond, Nicholas A.; Gawiser, Eric; Guaita, Lucia; Padilla, Nelson; Gronwall, Chile Caryl; Ciardullo, Robin; Lai, Kamson

    2011-01-01

    We present a rest-frame ultraviolet morphological analysis of 108 z = 2.1 Lyman Alpha Emitters (LAEs) in the Extended Chandra Deep Field South (ECDF-S) and compare it to a similar sample of 171 LAEs at z = 3.1 . Using Hubble Space Telescope (HST) images taken as part of the Galaxy Evolution From Morphology and SEDs survey, Great Observatories Origins Deep Survey, and Hubble Ultradeep Field surveys, we measure the size and photometric component distributions, where photo- metric components are defined as distinct clumps of UV-continuum emission. At both redshifts, the majority of LAEs have observed half-light radii physical properties derived from its SED. LAEs are found to be larger for galaxies with larger stellar mass, larger star formation rate, and larger dust obscuration, but there is no evidence for a trend between equivalent width and half-light radius at either redshift. The presence of these correlations suggests that a wide range of objects are being selected by LAE surveys at that redshift, including a significant fraction of objects for which a massive and moderately extended population of old stars underlies the young starburst giving rise to the Lya emission.

  16. THE BIVARIATE SIZE-LUMINOSITY RELATIONS FOR LYMAN BREAK GALAXIES AT z {approx} 4-5

    Energy Technology Data Exchange (ETDEWEB)

    Huang, Kuang-Han; Su, Jian [Johns Hopkins University, 3400 North Charles Street, Baltimore, MD 21218 (United States); Ferguson, Henry C. [Space Telescope Science Institute, 3700 San Martin Drive, Baltimore, MD 21218 (United States); Ravindranath, Swara, E-mail: kuanghan@pha.jhu.edu [The Inter-University Center for Astronomy and Astrophysics, Pune University Campus, Pune 411007, Maharashtra (India)

    2013-03-01

    We study the bivariate size-luminosity distribution of Lyman break galaxies (LBGs) selected at redshifts around 4 and 5 in GOODS and the HUDF fields. We model the size-luminosity distribution as a combination of log-normal distribution (in size) and Schechter function (in luminosity), therefore it enables a more detailed study of the selection effects. We perform extensive simulations to quantify the dropout-selection completenesses and measurement biases and uncertainties in two-dimensional size and magnitude bins, and transform the theoretical size-luminosity distribution to the expected distribution for the observed data. Using maximum-likelihood estimator, we find that the Schechter function parameters for B {sub 435}-dropouts and are consistent with the values in the literature, but the size distributions are wider than expected from the angular momentum distribution of the underlying dark matter halos. The slope of the size-luminosity (RL) relation is similar to those found for local disk galaxies, but considerably shallower than local early-type galaxies.

  17. THE BIVARIATE SIZE-LUMINOSITY RELATIONS FOR LYMAN BREAK GALAXIES AT z ∼ 4-5

    International Nuclear Information System (INIS)

    Huang, Kuang-Han; Su, Jian; Ferguson, Henry C.; Ravindranath, Swara

    2013-01-01

    We study the bivariate size-luminosity distribution of Lyman break galaxies (LBGs) selected at redshifts around 4 and 5 in GOODS and the HUDF fields. We model the size-luminosity distribution as a combination of log-normal distribution (in size) and Schechter function (in luminosity), therefore it enables a more detailed study of the selection effects. We perform extensive simulations to quantify the dropout-selection completenesses and measurement biases and uncertainties in two-dimensional size and magnitude bins, and transform the theoretical size-luminosity distribution to the expected distribution for the observed data. Using maximum-likelihood estimator, we find that the Schechter function parameters for B 435 -dropouts and are consistent with the values in the literature, but the size distributions are wider than expected from the angular momentum distribution of the underlying dark matter halos. The slope of the size-luminosity (RL) relation is similar to those found for local disk galaxies, but considerably shallower than local early-type galaxies.

  18. The applicability of ALPHA/PHOENIX/ANC nuclear design code system on Korean standard PWR's

    International Nuclear Information System (INIS)

    Lee, Kookjong; Choi, Kie-Yong; Lee, Hae-Chan; Roh, Eun-Rae

    1996-01-01

    For the Korean Standard Nuclear Power Plant (KSNPP) designed based on Combustion Engineering (CE) System 80, the Westinghouse nuclear design code system ALPHA/PHOENIX/ANC was applied to the follow-up design of initial and reload core of KSNPP. The follow-up design results of Yonggwang Unit 3 Cycle 1, 2 and Yonggwang Unit 4 Cycle 1 have shown good agreements with the measured data. The assemblywise power distributions have shown less than 2% average differences and critical boron concentrations have shown less than 20 ppm differences. All the low power physics test parameters are in good agreement. Consequently, APA design code system can be applied to KNSPP cores. (author)

  19. Alpha - Skew Pi - Armendariz Rings

    Directory of Open Access Journals (Sweden)

    Areej M Abduldaim

    2018-03-01

    Full Text Available In this article we introduce a new concept called Alpha-skew Pi-Armendariz rings (Alpha - S Pi - ARas a generalization of the notion of Alpha-skew Armendariz rings.Another important goal behind studying this class of rings is to employ it in order to design a modern algorithm of an identification scheme according to the evolution of using modern algebra in the applications of the field of cryptography.We investigate general properties of this concept and give examples for illustration. Furthermore, this paperstudy the relationship between this concept and some previous notions related to Alpha-skew Armendariz rings. It clearly presents that every weak Alpha-skew Armendariz ring is Alpha-skew Pi-Armendariz (Alpha-S Pi-AR. Also, thisarticle showsthat the concepts of Alpha-skew Armendariz rings and Alpha-skew Pi- Armendariz rings are equivalent in case R is 2-primal and semiprime ring.Moreover, this paper proves for a semicommutative Alpha-compatible ringR that if R[x;Alpha] is nil-Armendariz, thenR is an Alpha-S Pi-AR. In addition, if R is an Alpha - S Pi -AR, 2-primal and semiprime ring, then N(R[x;Alpha]=N(R[x;Alpha]. Finally, we look forwardthat Alpha-skew Pi-Armendariz rings (Alpha-S Pi-ARbe more effect (due to their properties in the field of cryptography than Pi-Armendariz rings, weak Armendariz rings and others.For these properties and characterizations of the introduced concept Alpha-S Pi-AR, we aspire to design a novel algorithm of an identification scheme.

  20. Binding of benzo(a)pyrene and (+/-)-7 beta,8 alpha-dihydroxy-9 alpha, 10 alpha-epoxy-7,8,9, 10-tetrahydrobenzo(a)pyrene to histones

    International Nuclear Information System (INIS)

    Sculley, T.B.; Zytkovicz, T.H.

    1983-01-01

    AKR-2B mouse embryo cells were incubated for 24 hr with [3H]benzo(a)pyrene, and the histones were isolated and analyzed using one- and two-dimensional gel electrophoresis and autoradiography. The results revealed that (a) histones H1, H2A, and H3 incorporated significant amounts of label whereas little or no label was associated with histones H2B and H4 and (b) electrophoresis of the histones in the Triton: acid: urea gel system caused labeled histones to have a slower migration than did the corresponding unlabeled histones. Additional studies such as incubation of (+/-)-7 beta,8 alpha-[3H]dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene with nuclei resulted in radioactive labeling of histones H1, H2A, H2B, and H3 and of high-mobility-group proteins HMG1 and HMG2. The low levels of label associated with histone H4 in the whole-cell and nuclear studies were further investigated by incubating isolated histones with (+/-)-7 beta,8 alpha-[3H]dihydroxy-9 alpha,10 alpha-epoxy-7,8,9,10-tetrahydrobenzo(a)pyrene. Under these conditions, negligible amounts of radioactivity were associated with H4, while significant labeling of H1, H2A, H2B, and H3 and other nuclear proteins was observed. The results suggest that factors other than the presence of suitable nucleophilic acceptor sites on the histones may be necessary for carcinogen binding

  1. Evaluation of GABAergic neuroactive steroid 3alpha-hydroxy-5alpha-pregnane-20-one as a neurobiological substrate for the anti-anxiety effect of ethanol in rats.

    Science.gov (United States)

    Hirani, Khemraj; Sharma, Ajay N; Jain, Nishant S; Ugale, Rajesh R; Chopde, Chandrabhan T

    2005-07-01

    Acute systemic ethanol administration is known to elevate plasma and cerebral levels of neuroactive steroid 3alpha-hydroxy-5alpha-pregnane-20-one (3alpha, 5alpha-THP; allopregnanolone) to a concentration sufficient to potentiate GABA(A) receptors. We have earlier demonstrated that 3alpha, 5alpha-THP mediates the antidepressant-like effect of ethanol in Porsolt forced swim test. The aim of the present study is to explain the relationship between endogenous GABAergic neurosteroids and anxiolytic effect of ethanol in Sprague-Dawley rats. The mediation of 3alpha, 5alpha-THP in the anti-anxiety effect of ethanol was assessed by pharmacological interactions of ethanol with various endogenous neurosteroidal modulators and using simulated physiological conditions of altered neurosteroid content in elevated plus maze (EPM) test. Pretreatment of 3alpha, 5alpha-THP (0.5-2.5 mug/rat, i.c.v.) or neurosteroidogenic agents such as 3alpha, 5alpha-THP precursor progesterone (5 or 10 mg/kg, i.p.), 11-beta hydroxylase inhibitor metyrapone (50 or 100 mg/kg, i.p.) or the GABA(A) receptor agonist muscimol (25 ng/rat, i.c.v.) significantly potentiated the anti-anxiety effect of ethanol (1 g/kg, i.p.). On the other hand, the GABAergic antagonistic neurosteroid dehydroepiandrosterone sulphate (DHEAS) (1 mg/kg, i.p.), the GABA(A) receptor blocker bicuculline (1 mg/kg, i.p.), the 5alpha-reductase inhibitor finasteride (50 x 2 mg/kg, s.c.) or the mitochondrial diazepam binding inhibitory receptor antagonist PK11195 (1 mg/kg, i.p.) reduced ethanol-induced preference of time spent and number of entries into open arms. Anti-anxiety effect of ethanol was abolished in adrenalectomized (ADX) rats as compared to sham-operated control. This ADX-induced blockade was restored by prior systemic injection of progesterone, signifying the contribution of peripheral steroidogenesis in ethanol anxiolysis. Socially isolated animals known to exhibit decreased brain 3alpha, 5alpha-THP and GABA(A) receptor

  2. E-PERM alpha surface monitor

    International Nuclear Information System (INIS)

    Fricke, V.

    1999-01-01

    Innovative Technology Summary Reports are designed to provide potential users with the information they need to quickly determine if a technology would apply to a particular environmental management problem. They are also designed for readers who may recommend that a technology be considered by prospective users. Each report describes a technology, system, or process that has been developed and tested with funding from DOE's Office of Science and Technology (OST). The E-PERMreg s ign Alpha Surface Monitor is an integrating electret ion chamber innovative technology used to measure alpha radiation on surfaces of materials. The technology is best used on surfaces with low contamination levels such as areas with potential for free release, but can also be used in areas with higher levels of contamination. Measurement accuracy and production of the E-PERM reg s ign Alpha Surface Monitor compared favorably with the baseline technology. The innovative technology cost is approximately 28% higher than the baseline with an average unit cost per reading costing %6.04 vs. $4.36; however, the flexibility of the E-PERMreg s ign Alpha Surface Monitor may offer advantages in ALARA, reduction of operator error, waste minimization, and measurement accuracy

  3. The ALPHA detector : Module Production and Assembly

    CERN Document Server

    Andresen, G; Bowe, P D; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Fujiwara, M C; Gill, D R; Hangst, J S; Hydomako, R; Jenkins, M J; Kurchaninov, L; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Povilus, A; Robicheaux, F; Sarid, E; Silveira, D M; Storey, J W; Thompson, R I; van der Werf, D P; Wurtele, J S; Yamazaki, Y; Ashkezari, M D; Baquero-Ruiz, M; Butler, E; Deller, A; Eriksson, S; Friesen, T; Gutierrez, A; Hardy, W N; Hayden, M E; Humphries, A J; Jonsell, S; McKenna, J T K; Menary, S; Pusa, P; Sampson, J; Seddon, D; Seif el Nasr, S; So, C; Thornhill, J; Wells, D; Jorgensen, L V

    2012-01-01

    ALPHA is one of the experiments situated at CERN's Antiproton Decelerator (AD). A Silicon Vertex Detector (SVD) is placed to surround the ALPHA atom trap. The main purpose of the SVD is to detect and locate antiproton annihilation events by means of the emitted charged pions. The SVD system is presented with special focus given to the design, fabrication and performance of the modules.

  4. How to estimate the 3D power spectrum of the Lyman-α forest

    Science.gov (United States)

    Font-Ribera, Andreu; McDonald, Patrick; Slosar, Anže

    2018-01-01

    We derive and numerically implement an algorithm for estimating the 3D power spectrum of the Lyman-α (Lyα) forest flux fluctuations. The algorithm exploits the unique geometry of Lyα forest data to efficiently measure the cross-spectrum between lines of sight as a function of parallel wavenumber, transverse separation and redshift. We start by approximating the global covariance matrix as block-diagonal, where only pixels from the same spectrum are correlated. We then compute the eigenvectors of the derivative of the signal covariance with respect to cross-spectrum parameters, and project the inverse-covariance-weighted spectra onto them. This acts much like a radial Fourier transform over redshift windows. The resulting cross-spectrum inference is then converted into our final product, an approximation of the likelihood for the 3D power spectrum expressed as second order Taylor expansion around a fiducial model. We demonstrate the accuracy and scalability of the algorithm and comment on possible extensions. Our algorithm will allow efficient analysis of the upcoming Dark Energy Spectroscopic Instrument dataset.

  5. Alpha-synuclein in cutaneous small nerve fibers

    Directory of Open Access Journals (Sweden)

    Siepmann T

    2016-10-01

    Full Text Available Timo Siepmann,1 Ben Min-Woo Illigens,2 Kristian Barlinn1 1Department of Neurology, University Hospital Carl Gustav Carus, Technische Universität Dresden, Dresden, Germany; 2Department of Neurology, Beth Israel Deaconess Medical Center, Harvard Medical School, Boston, MA, USA Abstract: Despite progression in the development of pharmacological therapy, treatment of alpha synucleinopathies, such as Parkinson’s disease (PD and some atypical parkinsonism syndromes, is still challenging. To date, our knowledge of the mechanisms whereby the pathological form of alpha-synuclein causes structural and functional damage to the nervous system is limited and, consequently, there is a lack of specific diagnostic tools to evaluate pathology in these patients and differentiate PD from other neurodegenerative proteinopathies. Recent studies indicated that alpha-synuclein deposition in cutaneous small nerve fibers assessed by skin biopsies might be a valid disease marker of PD and facilitate early differentiation of PD from atypical parkinsonism syndromes. This observation is relevant since early diagnosis may enable timely treatment and improve quality of life. However, challenges include the necessity of standardizing immunohistochemical analysis techniques and the identification of potential distinct patterns of intraneural alpha-synuclein deposition among synucleinopathies. In this perspective, we explore the scientific and clinical opportunities arising from alpha-synuclein assessment using skin biopsies. These include elucidation of the peripheral nervous system pathology of PD and other synucleinopathies, identification of novel targets to study response to neuroprotective treatment, and improvement of clinical management. Furthermore, we discuss future challenges in exploring the diagnostic value of skin biopsy assessment for alpha-synuclein deposition and implementing the technique in clinical practice. Keywords: Parkinson’s disease, diagnosis, skin

  6. Liquid scintillation alpha particle spectrometry. Progress report

    International Nuclear Information System (INIS)

    Bell, L.L.; Hakooz, S.A.; Johnson, L.O.; Nieschmidt, E.B.; Meikrantz, D.H.

    1979-12-01

    Objective to develop a technique whereby Pu may be put into solution, extracted by solvent extraction into a suitable extractive scintillant and subsequently counted. Presented here are results of attempts to separate beta and alpha activities through pulse shape discrimination. A qualitative discussion is given which yields alpha particle peak widths, resolution and response. The detection efficiency for alpha particles in a liquid scintillant is 100%. Present detection sensitivities of the equipment being used are: 4.5 x 10 -6 μCi (100 s), 1.2 x 10 -6 μCi (1000 s), and 4.0 x 10 -7 μCi (10,000 s) at the 3 sigma level. The detectability of a particular alpha-emitting species is strongly dependent upon the population of other species. The ability to discriminate depends upon the system resolution. 14 figures, 2 tables

  7. Synthesis of tritiated 1-alpha-methadol and 1-alpha-acetylmethadol

    Energy Technology Data Exchange (ETDEWEB)

    Thang, D.C.; Nam, N.H.; Pontikis, R. (Institut National de la Sante et de la Recherche Medicale (INSERM), Hopital Fernand Widal, 75 - Paris (France)); Pichat, L. (CEA Centre d' Etudes Nucleaires de Saclay, 91 - Gif-sur-Yvette (France). Service des Molecules Marquees)

    1982-04-01

    dl-Methadone was resolved by crystallization of its ammonium d- ..cap alpha.. -bromocamphor-..pi..-sulfonate salt to give d-methadone. The latter in ethyl acetate solution was reduced with tritium gas to 1-..cap alpha..-methadol /sup 3/H in presence of Adams platinum oxide at normal temperature and pressure. Acetylation of 1-..cap alpha..-carbinol hydrochloride by means of acetyl chloride afforded 1-..cap alpha..-acetylmethadol /sup 3/H, specific activity: 20 Ci/mMole. The positions and extent of tritium labelling were determined by /sup 3/H NMR spectroscopy.

  8. The effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine, and antagonists yohimbine and efaroxan, on the spinal cholinergic receptor system in the rat

    DEFF Research Database (Denmark)

    Abelson, Klas S P; Höglund, A Urban

    2004-01-01

    Cholinergic agonists produce spinal antinociception via mechanisms involving an increased release of intraspinal acetylcholine. The cholinergic receptor system interacts with several other receptor types, such as alpha2-adrenergic receptors. To fully understand these interactions, the effects...... of various receptor ligands on the cholinergic system must be investigated in detail. This study was initiated to investigate the effects of the alpha2-adrenergic receptor agonists clonidine and rilmenidine and the alpha2-adrenergic receptor antagonists yohimbine and efaroxan on spinal cholinergic receptors......, all ligands possessed affinity for nicotinic receptors. Clonidine and yohimbine binding was best fit to a one site binding curve and rilmenidine and efaroxan to a two site binding curve. The present study demonstrates that the tested alpha2-adrenergic receptor ligands affect intraspinal acetylcholine...

  9. Non-LTE hydrogen-line formation in moving prominences

    Science.gov (United States)

    Heinzel, P.; Rompolt, B.

    1986-01-01

    The behavior of hydrogen-line brightness variations, depending on the prominence-velocity changes were investigated. By solving the NON-Local thermodynamic equilibrium (LTE) problem for hydrogen researchers determine quantitatively the effect of Doppler brightening and/or Doppler dimming (DBE, DDE) in the lines of Lyman and Balmer series. It is demonstrated that in low-density prominence plasmas, DBE in H alpha and H beta lines can reach a factor of three for velocities around 160 km/sec, while the L alpha line exhibits typical DDE. L beta brightness variations follow from a combined DBE in the H alpha and DDE in L alpha and L beta itself, providing that all relevant multilevel interlocking processes are taken into account.

  10. Towards laser spectroscopy of antihydrogen

    NARCIS (Netherlands)

    Walz, J.; Pahl, A.; Eikema, K.S.E.; Hansch, T.W.

    2000-01-01

    The development of the first continuous coherent source at 121.56 nm is described. Radiation at this wavelength of Lyman-alpha can be used for laser-cooling of antihydrogen on the strong 1S-2P transition. It also opens up a possibility for precision spectroscopy that requires just a few antihydrogen

  11. First Attempts at Antihydrogen Trapping in ALPHA

    CERN Document Server

    Andresen, G B; Bowe, P D; Bray, C C; Butler, E; Cesar, C L; Chapman, S; Charlton, M; Fajans, J; Funakoshi, R; Gill, D R; Hangst, J S; Hardy, W N; Hayano, R S; Hayden, M E; Humphries, A J; Hydomako, R; Jenkins, M J; Jørgensen, L V; Kurchaninov, L; Lambo, R; Madsen, N; Nolan, P; Olchanski, K; Olin, A; Page, R D; Povilus, A; Pusa, P; Robicheaux, F; Sarid, E; Seif El Nasr, S; Silveira, D M; Storey, J W; Thompson, R I; Van der Werf, D P; Wasilenko, L; Wurtele, J S; Yamazaki, Y; Fujiwara, M C

    2008-01-01

    We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

  12. A Lyman Break Galaxy Candidate at z ~ 9

    Science.gov (United States)

    Henry, Alaina L.; Malkan, Matthew A.; Colbert, James W.; Siana, Brian; Teplitz, Harry I.; McCarthy, Patrick

    2008-06-01

    We report the discovery of a z ~ 9 Lyman break galaxy candidate, selected from the NICMOS Parallel Imaging Survey as a J-dropout with J110 - H160 = 1.7. Spitzer/IRAC photometry reveals that the galaxy has a blue H160 - 3.6 μm color and a spectral break between 3.6 and 4.5 μm. We interpret this break as the Balmer break and derive a best-fit photometric redshift of z ~ 9. We use Monte Carlo simulations to test the significance of this photometric redshift, and we show that there is a 96% probability of z >= 7. We estimate that the lower limit to the comoving number density of such galaxies at z ~ 9 is phi > 3.8 × 10-6 Mpc-3. If the high redshift of this galaxy is confirmed, this will indicate that the luminous end of the rest-frame UV luminosity function has not evolved substantially from z ~ 9 to z ~ 3. Still, some small degeneracy remains between this z ~ 9 model and models at z ~ 2-3 deep optical imaging (reaching IAB ~ 29) can rule out the lower z models. This work is based in part on observations made with the Spitzer Space Telescope, which is operated by the Jet Propulsion Laboratory (JPL), California Institute of Technology, under a contract with NASA. Support for this work was provided by NASA through an award issued by JPL/Caltech. This work is also based in part on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposals 9484, 9865, 10226, and 10899.

  13. Test plan for FY-91 alpha CAM evaluation

    International Nuclear Information System (INIS)

    Winberg, M.R.

    1991-03-01

    This report describes the test plan for evaluating the Merlin Gerin, Inc., Edgar alpha continuous air monitor (CAM) and associated analysis system to be conducted by Idaho National Engineering Laboratory (INEL) for the Department of Energy. INEL has evaluated other commercial alpha CAM systems to detect transuranic contaminants during waste handling and retrieval operations. This test plan outlines experimental methods, sampling methods, sampling and analysis techniques, and equipment needed and safety and quality requirements to test the commercial CAM. 8 refs., 3 figs

  14. Pollen Dispersal by Catapult: Experiments of Lyman J. Briggs on the Flower of Mountain Laurel

    Science.gov (United States)

    Nimmo, John R.; Hermann, Paula M.; Kirkham, M. B.; Landa, Edward R.

    2014-09-01

    The flower of Kalmia latifolia L. employs a catapult mechanism that flings its pollen to considerable distances. Physicist Lyman J. Briggs investigated this phenomenon in the 1950s after retiring as longtime director of the National Bureau of Standards, attempting to explain how hydromechanical effects inside the flower's stamen could make it possible. Briggs's unfinished manuscript implies that liquid under negative pressure generates stress, which, superimposed on the stress generated from the flower's growth habit, results in force adequate to propel the pollen as observed. With new data and biophysical understanding to supplement Briggs's experimental results and research notes, we show that his postulated negative-pressure mechanism did not play the exclusive and crucial role that he credited to it, though his revisited investigation sheds light on various related processes. Important issues concerning the development and reproductive function of Kalmia flowers remain unresolved, highlighting the need for further biophysical advances.

  15. Regulation and function of the alpha2 adrenergic autoreceptor in the central nervous system

    International Nuclear Information System (INIS)

    Spengler, R.N.

    1987-01-01

    The purpose of this investigation was to determine whether changes observed in the number of alpha 2 adrenergic receptors in the brain as measured by radioligand binding experiments reflect changes in the function of alpha 2 autoregulatory receptors which are located on noradrenergic nerve terminals. Inhibition by clonidine of field stimulated 3 H-norepinephrine ( 3 H-NE) release from rat hippocampal slices before and after several drug treatments was analyzed to investigate changes in alpha 2 adrenergic receptor function. Clonidine in a concentration-dependent manner inhibited 3 H-NE release. The effect of clonidine was blocked by the specific alpha 2 adrenergic receptor antagonist, idazoxan. The cumulative administration of clonidine generated a smooth and well-fitted log-concentration-effect curve. Results are presented which demonstrate that this technique can be employed to investigate the role of changes in the function of the alpha 2 autoregulatory receptor. The present investigation also examined representatives of four drug classes which have been shown to alter the specific binding of 3 H-clonidine to neural membranes to determine whether changes in the alpha 2 autoregulatory receptor function also occur

  16. Development of the prototype data management system of the solar H-alpha full disk observation

    Science.gov (United States)

    Wei, Ka-Ning; Zhao, Shi-Qing; Li, Qiong-Ying; Chen, Dong

    2004-06-01

    The Solar Chromospheric Telescope in Yunnan Observatory generates about 2G bytes fits format data per day. Huge amounts of data will bring inconvenience for people to use. Hence, data searching and sharing are important at present. Data searching, on-line browsing, remote accesses and download are developed with a prototype data management system of the solar H-alpha full disk observation, and improved by the working flow technology. Based on Windows XP operating system and MySQL data management system, a prototype system of browse/server model is developed by JAVA and JSP. Data compression, searching, browsing, deletion need authority and download in real-time have been achieved.

  17. Tumor necrosis factor-alpha modulates human in vivo lipolysis

    DEFF Research Database (Denmark)

    Plomgaard, Peter; Fischer, Christian P; Ibfelt, Tobias

    2008-01-01

    CONTEXT: Low-grade systemic inflammation is a feature of most lifestyle-related chronic diseases. Enhanced TNF-alpha concentrations have been implicated in the development of hyperlipidemia. OBJECTIVE: We hypothesized that an acute elevation of TNF-alpha in plasma would cause an increase...... in lipolysis, increasing circulatory free fatty acid (FFA) levels. SUBJECTS AND METHODS: Using a randomized controlled, crossover design, healthy young male individuals (n = 10) received recombinant human (rh) TNF-alpha (700 ng/m(-2).h(-1)) for 4 h, and energy metabolism was evaluated using a combination...... of tracer dilution methodology and arterial-venous differences over the leg. RESULTS: Plasma TNF-alpha levels increased from 0.7 +/- 0.04 to 16.7 +/- 1.8 pg/ml, and plasma IL-6 increased from 1.0 +/- 0.2 to 9.2 +/- 1.0 pg/ml (P alpha infusion. Here, we demonstrate that 4-h rhTNF-alpha...

  18. Hippocampal 3alpha,5alpha-THP may alter depressive behavior of pregnant and lactating rats.

    Science.gov (United States)

    Frye, Cheryl A; Walf, Alicia A

    2004-07-01

    The 5alpha-reduced metabolite of progesterone (P), 5alpha-pregnan-3alpha-ol-20-one (3alpha,5alpha-THP), may mediate progestins' effects to reduce depressive behavior of female rats in part through actions in the hippocampus. To investigate, forced swim test behavior and plasma and hippocampal progestin levels were assessed in groups of rats expected to differ in their 3alpha,5alpha-THP levels due to endogenous differences (pregnant and postpartum), administration of a 5alpha-reductase inhibitor (finasteride; 50 mg/kg sc), and/or gestational stress [prenatal stress (PNS)], an animal model of depression. Pregnant rats had higher plasma and hippocampal 3alpha,5alpha-THP levels and less depressive behavior (decreased immobility, increased struggling and swimming) in the forced swim test than did postpartum rats. Finasteride, compared to vehicle-administration, reduced plasma and hippocampal 3alpha,5alpha-THP levels and increased depressive behavior (increased immobility, decreased struggling and swimming). PNS was associated with lower hippocampal, but not plasma, 3alpha,5alpha-THP levels and increased swimming compared to that observed in control rats. Together, these data suggest that 3alpha,5alpha-THP in the hippocampus may mediate antidepressive behavior of female rats.

  19. Anisotropy of favoured alpha transitions producing even-even deformed nuclei

    International Nuclear Information System (INIS)

    Tavares, O.A.P.

    1997-05-01

    The anisotropy in favoured alpha transitions which produce even-even deformed nuclei is discussed. A simple, Gamow's-like model which takes into account the quadrupole deformation of the product nucleus has been formulated to calculate the alpha decay half-life. It is assumed that before tunneling into a purely Coulomb potential barrier the two-body system oscillated isotropically, thus giving rise to an equivalent, average preferential polar direction θ 0 (referred to the symmetry axis of the ellipsoidal shape of the product nucleus) for alpha emission in favoured alpha transitions of even-even nuclei. (author)

  20. Advanced computer-controlled automatic alpha-beta air sample counter

    International Nuclear Information System (INIS)

    Howell, W.P.; Bruinekool, D.J.; Stapleton, E.E.

    1983-01-01

    An improved computer controlled automatic alpha-beta air sample counter was developed, based upon an earlier automatic air sample counter design. The system consists of an automatic sample changer, an electronic counting system utilizing a large silicon diode detector, a small desk-type microcomputer, a high speed matrix printer, and the necessary data interfaces. The system is operated by commands from the keyboard and programs stored on magnetic tape cassettes. The programs provide for background counting, Chi 2 test, radon subtraction, and sample counting for sample periods of one day to one week. Output data are printed by the matrix printer on standard multifold paper. The data output includes gross beta, gross alpha, and plutonium results. Data are automatically corrected for background, counter efficiency, and in the gross alpha and plutonium channels, for the presence of radon

  1. A Lyman Break Galaxy in the Epoch of Reionization from Hubble Space Telescope (HST) Grism Spectroscopy

    Science.gov (United States)

    Rhoads, James E.; Malhotra, Sangeeta; Stern, Daniel K.; Gardner, Jonathan P.; Dickinson, Mark; Pirzkal, Norbert; Spinrad, Hyron; Reddy, Naveen; Dey, Arjun; Hathi, Nimish; hide

    2013-01-01

    Slitless grism spectroscopy from space offers dramatic advantages for studying high redshift galaxies: high spatial resolution to match the compact sizes of the targets, a dark and uniform sky background, and simultaneous observation over fields ranging from five square arcminutes (HST) to over 1000 square arcminutes (Euclid). Here we present observations of a galaxy at z = 6.57 the end of the reioinization epoch identified using slitless HST grism spectra from the PEARS survey (Probing Evolution And Reionization Spectroscopically) and reconfirmed with Keck + DEIMOS. This high redshift identification is enabled by the depth of the PEARS survey. Substantially higher redshifts are precluded for PEARS data by the declining sensitivity of the ACS grism at greater than lambda 0.95 micrometers. Spectra of Lyman breaks at yet higher redshifts will be possible using comparably deep observations with IR-sensitive grisms.

  2. Probing slowly exchanging protein systems via {sup 13}C{sup {alpha}}-CEST: monitoring folding of the Im7 protein

    Energy Technology Data Exchange (ETDEWEB)

    Hansen, Alexandar L.; Bouvignies, Guillaume; Kay, Lewis E., E-mail: kay@pound.med.utoronto.ca [University of Toronto, Departments of Molecular Genetics, Biochemistry and Chemistry (Canada)

    2013-03-15

    A {sup 13}C{sup {alpha}} chemical exchange saturation transfer based experiment is presented for the study of protein systems undergoing slow interconversion between an 'observable' ground state and one or more 'invisible' excited states. Here a labeling strategy whereby [2-{sup 13}C]-glucose is the sole carbon source is exploited, producing proteins with {sup 13}C at the C{sup {alpha}} position, while the majority of residues remain unlabeled at CO or C{sup {beta}}. The new experiment is demonstrated with an application to the folding reaction of the Im7 protein that involves an on-pathway excited state. The obtained excited state {sup 13}C{sup {alpha}} chemical shifts are cross validated by comparison to values extracted from analysis of CPMG relaxation dispersion profiles, establishing the utility of the methodology.

  3. Lyman Break Galaxies At z 2 In The GOODS Fields

    Science.gov (United States)

    Haberzettl, Lutz; Williger, G.; Lehnert, M.; Nesvadba, N.

    2009-12-01

    Lyman Break Galaxies (LBGs) have been the benchmarks against which other samples of high redshift galaxies have been compared for the last 2 decades. They are unique in that no other selection mechanism allows us to study galaxies selected in a consistent manner over the span of redshifts from z=0 to 7. An important remaining gap is the redshift range z ˜ 1.5-2.5, which includes near UV (NUV)-band drop-outs. We present first results of a search for LBGs at these redshifts using very sensitive multi-frequency data from the far UV to mid-IR of the GOODS CDF-S and HDF-N. We modelled colors of star-forming galaxies, and found only a small overlap with the BM/BX selection method (Adelberger et al. 2004, ApJ, 607, 226). We developed new color selection criteria using GALEX NUV and optical photometry to identify high star formation galaxies, including NUV-dropouts for 2.0methods, we identified a sample of ? z˜ 2 LBG candidates in both the GOODS CDF-S and the HDF-N. A first analysis of the mean SED of our LBG candidate sample shows results consistent with red LBGs at z ˜ 1, indicating massive galaxies with high star formation rates. Nearly 10% of our selected LBG candidates have mid-IR (IRAC+MIPS) colors comparable both to z ˜ 3 IR-luminous LBGs, which are believed to be dusty, vigorously star-forming massive progenitors of modern ellipticals.

  4. Absorption of lower hybrid waves by alpha particles in ITER

    International Nuclear Information System (INIS)

    Imbeaux, F.; Peysson, Y.; Eriksson, L.G.

    2003-01-01

    Absorption of lower hybrid (LH) waves by alpha particles may reduce significantly the current drive efficiency of the waves in a reactor or burning plasma experiment. This absorption is quantified for ITER using the ray-tracing+2D relativistic Fokker-Planck code Delphine. The absorption is calculated as a function of the superthermal alpha particle density, which is constant in these simulations, for two candidate frequencies for the LH system of ITER. Negligible absorption by alpha particles at 3.7 GHz requires n(alpha,supra) = 7.5 10 16 m -3 , while no significant impact on the driven current is found at 5 GHz, even if n(alpha,supra) = 1.5 10 18 m -3 . (authors)

  5. The heavy quarkonium spectrum at order $m\\alpha_{s}^{5}\\ln\\alpha_{s}$

    CERN Document Server

    Brambilla, Nora; Soto, Joan; Vairo, Antonio

    1999-01-01

    We compute the complete leading-log terms of the next-to-next-to-next-to-leading-order corrections to potential NRQCD. As a by-product we obtain the leading logs at $O(m\\alpha_s^5)$ in the heavy quarkonium spectrum. These leading logs, when $\\Lambda_{QCD} \\ll m\\alpha_s^2$, give the complete $O(m\\alpha_s^5 \\ln \\alpha_s)$ corrections to the heavy quarkonium spectrum.

  6. Conditioning of alpha bearing wastes

    International Nuclear Information System (INIS)

    1991-01-01

    Alpha bearing wastes are generated during the reprocessing of spent fuel, mixed oxide fuel fabrication, decommissioning and other activities. The safe and effective management of these wastes is of particular importance owing to the radiotoxicity and long lived characteristics of certain transuranic (TRU) elements. The management of alpha bearing wastes involves a number of stages which include collection, characterization, segregation, treatment, conditioning, transport, storage and disposal. This report describes the currently available matrices and technologies for the conditioning of alpha wastes and relates them to their compatibility with the other stages of the waste management process. The selection of a specific immobilization process is dependent on the waste treatment state and the subsequent handling, transport, storage and disposal requirements. The overall objectives of immobilization are similar for all waste producers and processors, which are to produce: (a) Waste forms with sufficient mechanical, physical and chemical stability to satisfy all stages of handling, transport and storage (referred to as the short term requirements), and (b) Waste forms which will satisfy disposal requirements and inhibit the release of radionuclides to the biosphere (referred to as the long term requirements). Cement and bitumen processes have already been successfully applied to alpha waste conditioning on the industrial scale in many of the IAEA Member States. Cement systems based on BFS and pozzolanic cements have emerged as the principal encapsulation matrices for the full range of alpha bearing wastes. Alternative technologies, such as polymers and ceramics, are being developed for specific waste streams but are unlikely to meet widespread application owing to cost and process complexity. The merits of alpha waste conditioning are improved performance in transport, storage and disposal combined with enhanced public perception of waste management operations. These

  7. Methods to Directly Image Exoplanets around Alpha Centauri and Other Multi-Star Systems

    Science.gov (United States)

    Belikov, R.; Sirbu, D.; Bendek, E.; Pluzhnik, E.

    2017-12-01

    The majority of FGK stars exist as multi-star star systems, and thus form a potentially rich target sample for direct imaging of exoplanets. A large fraction of these stars have starlight leakage from their companion that is brighter than rocky planets. This is in particular true of Alpha Centauri, which is 2.4x closer and about an order of magnitude brighter than any other FGK star, and thus may be the best target for any direct imaging mission, if the light of both stars can be suppressed. Thus, the ability to suppress starlight from two stars improves both the quantity and quality of Sun-like targets for missions such as WFIRST, LUVOIR, and HabEx. We present an analysis of starlight leak challenges in multi-star systems and techniques to solve those challenges, with an emphasis on imaging Alpha Centauri with WFIRST. For the case of internal coronagraphs, the fundamental problem appears to be independent wavefront control of multiple stars (at least if the companion is close enough or bright enough that it cannot simply be removed by longer exposure times or post-processing). We present a technique called Multi-Star Wavefront Control (MSWC) as a solution to this challenge and describe the results of our technology development program that advanced MSWC to TRL 3. Our program consisted of lab demonstrations of dark zones in two-star systems, validated simulations, as well as simulated predictions demonstrating that with this technology, contrasts needed for Earth-like planets are in principle achievable. We also demonstrate MSWC in Super-Nyquist mode, which allows suppression of multiple stars at separations greater than the spatial Nyquist limit of the deformable mirror.

  8. Can sterile neutrinos be ruled out as warm dark matter candidates?

    CERN Document Server

    Viel, M; Hähnelt, M G; Matarrese, S; Riotto, Antonio; Viel, Matteo; Lesgourgues, Julien; Haehnelt, Martin G.; Matarrese, Sabino; Riotto, Antonio

    2006-01-01

    We present constraints on the mass of Warm Dark Matter (WDM) particles from a combined analysis of the matter power spectrum inferred from the SDSS (Sloan Digital Sky Survey) Lyman-alpha flux power spectrum at 2.2 10 keV (2 sigma) if the WDM consists of sterile neutrinos and m_wdm > 2 keV (2 sigma) for early decoupled thermal relics. These results significantly improve our previous estimates based on high-resolution Lyman-alpha forest data at lower redshift. Our new limits are consistent with those of Seljak et al. (2006), albeit ~ 30 % smaller. If we combine this bound with the constraint derived from X-ray flux observations in the Coma cluster periphery (Boyarsky et al.), we find that the only allowed sterile neutrino mass is ~ 10 keV (in the standard production scenario with non-resonant neutrino oscillations). Adding constraints based on X-ray fluxes from the Andromeda galaxy or the Milky Way, we find that dark matter particles cannot be sterile neutrinos, unless the latter are produced by resonant oscill...

  9. Stochastic resonance in underdamped periodic potential systems with alpha stable Lévy noise

    Science.gov (United States)

    Liu, Ruo-Nan; Kang, Yan-Mei

    2018-06-01

    In this paper, we investigate the effect of alpha stable Lévy noise with alpha stability index α (0 noise (0 noise has a more notable impact on the resonant effect of the asymmetric ratchet potential than that of the symmetric sinusoidal potential because of symmetry breaking.

  10. Penetration of HEPA-filters by alpha recoil aerosols

    International Nuclear Information System (INIS)

    McDowell, W.J.; Seeley, F.G.; Ryan, M.P.

    1977-01-01

    Results of work confirming that alpha-emitting particulate matter penetrates high-efficiency filter media much more effectively than do nonradioactive or beta-gamma-active aerosols are reported. Filter retention efficiencies appreciably lower than the 99.97% expected for ordinary particulate matter have been observed with 212 Pb, 253 Es, 238 Pu and 239 Pu sources, indicating that the phenomenon is common to all of these. Similar amounts of a beta-gamma-active material placed in the test filter system showed no migration, but when homogeneously mixed with alpha-active material, the gamma activity migrated along with the alpha material. (U.K.)

  11. Agonist-induced affinity alterations of a central nervous system. cap alpha. -bungarotoxin receptor

    Energy Technology Data Exchange (ETDEWEB)

    Lukas, R.J.; Bennett, E.L.

    1979-01-01

    The ability of cholinergic agonists to block the specific interaction of ..cap alpha..-bungarotoxin (..cap alpha..-Bgt) with membrane-bound sites derived from rat brain is enhanced when membranes are preincubated with agonist. Thus, pretreatment of ..cap alpha..-Bgt receptors with agonist (but not antagonist) causes transformation of sites to a high-affinity form toward agonist. This change in receptor state occurs with a half-time on the order of minutes, and is fully reversible on dilution of agonist. The results are consistent with the identity of ..cap alpha..-Bgt binding sites as true central nicotinic acetylcholine receptors. Furthermore, this agonist-induced alteration in receptor state may represent an in vitro correlate of physiological desensitization. As determined from the effects of agonist on toxin binding isotherms, and on the rate of toxin binding to specific sites, agonist inhibition of toxin binding to the high-affinity state is non-competitive. This result suggests that there may exist discrete toxin-binding and agonist-binding sites on central toxin receptors.

  12. Energy dependence of event shapes and of $\\alpha_s$ at LEP 2

    CERN Document Server

    Abreu, P; Adye, T; Adzic, P; Albrecht, Z; Alderweireld, T; Alekseev, G D; Alemany, R; Allmendinger, T; Allport, P P; Almehed, S; Amaldi, Ugo; Amapane, N; Amato, S; Anassontzis, E G; Andersson, P; Andreazza, A; Andringa, S; Antilogus, P; Apel, W D; Arnoud, Y; Åsman, B; Augustin, J E; Augustinus, A; Baillon, Paul; Bambade, P; Barão, F; Barbiellini, Guido; Barbier, R; Bardin, Dimitri Yuri; Barker, G; Baroncelli, A; Battaglia, Marco; Baubillier, M; Becks, K H; Begalli, M; Behrmann, A; Beillière, P; Belokopytov, Yu A; Belous, K S; Benekos, N C; Benvenuti, Alberto C; Bérat, C; Berggren, M; Bertini, D; Bertrand, D; Besançon, M; Bianchi, F; Bigi, M; Bilenky, S M; Bizouard, M A; Bloch, D; Blom, H M; Bonesini, M; Bonivento, W; Boonekamp, M; Booth, P S L; Borgland, A W; Borisov, G; Bosio, C; Botner, O; Boudinov, E; Bouquet, B; Bourdarios, C; Bowcock, T J V; Boyko, I; Bozovic, I; Bozzo, M; Branchini, P; Brenke, T; Brenner, R A; Brückman, P; Brunet, J M; Bugge, L; Buran, T; Burgsmüller, T; Buschbeck, Brigitte; Buschmann, P; Cabrera, S; Caccia, M; Calvi, M; Camporesi, T; Canale, V; Carena, F; Carroll, L; Caso, Carlo; Castillo-Gimenez, M V; Cattai, A; Cavallo, F R; Chabaud, V; Chapkin, M M; Charpentier, P; Chaussard, L; Checchia, P; Chelkov, G A; Chierici, R; Chliapnikov, P V; Chochula, P; Chorowicz, V; Chudoba, J; Cieslik, K; Collins, P; Contri, R; Cortina, E; Cosme, G; Cossutti, F; Cowell, J H; Crawley, H B; Crennell, D J; Crépé, S; Crosetti, G; Cuevas-Maestro, J; Czellar, S; Davenport, Martyn; Da Silva, W; Deghorain, A; Della Ricca, G; Delpierre, P A; Demaria, N; De Angelis, A; de Boer, Wim; De Clercq, C; De Lotto, B; De Min, A; De Paula, L S; Dijkstra, H; Di Ciaccio, Lucia; Dolbeau, J; Doroba, K; Dracos, M; Drees, J; Dris, M; Duperrin, A; Durand, J D; Eigen, G; Ekelöf, T J C; Ekspong, Gösta; Ellert, M; Elsing, M; Engel, J P; Erzen, B; Espirito-Santo, M C; Falk, E; Fanourakis, G K; Fassouliotis, D; Fayot, J; Feindt, Michael; Fenyuk, A; Ferrari, P; Ferrer, A; Ferrer-Ribas, E; Ferro, F; Fichet, S; Firestone, A; Flagmeyer, U; Föth, H; Fokitis, E; Fontanelli, F; Franek, B J; Frodesen, A G; Frühwirth, R; Fulda-Quenzer, F; Fuster, J A; Galloni, A; Gamba, D; Gamblin, S; Gandelman, M; García, C; Gaspar, C; Gaspar, M; Gasparini, U; Gavillet, P; Gazis, E N; Gelé, D; Ghodbane, N; Gil, I; Glege, F; Gokieli, R; Golob, B; Gómez-Ceballos, G; Gonçalves, P; González-Caballero, I; Gopal, Gian P; Gorn, L; Górski, M; Guz, Yu; Gracco, Valerio; Grahl, J; Graziani, E; Green, C; Grimm, H J; Gris, P; Grosdidier, G; Grzelak, K; Günther, M; Guy, J; Hahn, F; Hahn, S; Haider, S; Hallgren, A; Hamacher, K; Hansen, J; Harris, F J; Hedberg, V; Heising, S; Hernández, J J; Herquet, P; Herr, H; Hessing, T L; Heuser, J M; Higón, E; Holmgren, S O; Holt, P J; Hoorelbeke, S; Houlden, M A; Hrubec, Josef; Huet, K; Hughes, G J; Hultqvist, K; Jackson, J N; Jacobsson, R; Jalocha, P; Janik, R; Jarlskog, C; Jarlskog, G; Jarry, P; Jean-Marie, B; Johansson, E K; Jönsson, P E; Joram, C; Juillot, P; Kapusta, F; Karafasoulis, K; Katsanevas, S; Katsoufis, E C; Keränen, R; Kersevan, Borut P; Khomenko, B A; Khovanskii, N N; Kiiskinen, A P; King, B J; Kinvig, A; Kjaer, N J; Klapp, O; Klein, H; Kluit, P M; Kokkinias, P; Koratzinos, M; Kostyukhin, V; Kourkoumelis, C; Kuznetsov, O; Krammer, Manfred; Kriznic, E; Krstic, J; Krumshtein, Z; Kubinec, P; Kurowska, J; Kurvinen, K L; Lamsa, J; Lane, D W; Langefeld, P; Lapin, V; Laugier, J P; Lauhakangas, R; Leder, Gerhard; Ledroit, F; Lefébure, V; Leinonen, L; Leisos, A; Leitner, R; Lemonne, J; Lenzen, Georg; Lepeltier, V; Lesiak, T; Lethuillier, M; Libby, J; Liko, D; Lipniacka, A; Lippi, I; Lörstad, B; Loken, J G; Lopes, J H; López, J M; López-Fernandez, R; Loukas, D; Lutz, P; Lyons, L; MacNaughton, J N; Mahon, J R; Maio, A; Malek, A; Malmgren, T G M; Maltezos, S; Malychev, V; Mandl, F; Marco, J; Marco, R P; Maréchal, B; Margoni, M; Marin, J C; Mariotti, C; Markou, A; Martínez-Rivero, C; Martínez-Vidal, F; Martí i García, S; Mastroyiannopoulos, N; Matorras, F; Matteuzzi, C; Matthiae, Giorgio; Masik, J; Mazzucato, F; Mazzucato, M; McCubbin, M L; McKay, R; McNulty, R; McPherson, G; Meroni, C; Meyer, W T; Migliore, E; Mirabito, L; Mitaroff, Winfried A; Mjörnmark, U; Moa, T; Moch, M; Møller, R; Mönig, K; Monge, M R; Moreau, X; Morettini, P; Morton, G A; Müller, U; Münich, K; Mulders, M; Mulet-Marquis, C; Muresan, R; Murray, W J; Muryn, B; Myatt, Gerald; Myklebust, T; Naraghi, F; Nassiakou, M; Navarria, Francesco Luigi; Navas, S; Nawrocki, K; Negri, P; Némécek, S; Neufeld, N; Neumeister, N; Nicolaidou, R; Nielsen, B S; Nikolenko, M; Nomokonov, V P; Normand, Ainsley; Nygren, A; Obraztsov, V F; Olshevskii, A G; Onofre, A; Orava, Risto; Orazi, G; Österberg, K; Ouraou, A; Paganoni, M; Paiano, S; Pain, R; Paiva, R; Palacios, J; Palka, H; Papadopoulou, T D; Papageorgiou, K; Pape, L; Parkes, C; Parodi, F; Parzefall, U; Passeri, A; Passon, O; Pegoraro, M; Peralta, L; Pernicka, Manfred; Perrotta, A; Petridou, C; Petrolini, A; Phillips, H T; Pierre, F; Pimenta, M; Piotto, E; Podobnik, T; Pol, M E; Polok, G; Poropat, P; Pozdnyakov, V; Privitera, P; Pukhaeva, N; Pullia, Antonio; Radojicic, D; Ragazzi, S; Rahmani, H; Ratoff, P N; Read, A L; Rebecchi, P; Redaelli, N G; Regler, Meinhard; Reid, D; Reinhardt, R; Renton, P B; Resvanis, L K; Richard, F; Rídky, J; Rinaudo, G; Røhne, O M; Romero, A; Ronchese, P; Rosenberg, E I; Rosinsky, P; Roudeau, Patrick; Rovelli, T; Royon, C; Ruhlmann-Kleider, V; Ruiz, A; Saarikko, H; Sacquin, Yu; Sadovskii, A; Sajot, G; Salt, J; Sampsonidis, D; Sannino, M; Schneider, H; Schwemling, P; Schwering, B; Schwickerath, U; Schyns, M A E; Scuri, F; Seager, P; Sedykh, Yu; Segar, A M; Sekulin, R L; Shellard, R C; Sheridan, A; Siebel, M; Simard, L C; Simonetto, F; Sissakian, A N; Smadja, G; Smirnov, N; Smirnova, O G; Smith, G R; Sopczak, André; Sosnowski, R; Spassoff, Tz; Spiriti, E; Sponholz, P; Squarcia, S; Stanescu, C; Stanic, S; Stevenson, K; Stocchi, A; Strub, R; Stugu, B; Szczekowski, M; Szeptycka, M; Tabarelli de Fatis, T; Tegenfeldt, F; Terranova, F; Thomas, J; Timmermans, J; Tinti, N; Tkatchev, L G; Todorova-Nová, S; Tomaradze, A G; Tomé, B; Tonazzo, A; Tortora, L; Tranströmer, G; Treille, D; Tristram, G; Trochimczuk, M; Troncon, C; Tsirou, A L; Turluer, M L; Tyapkin, I A; Tzamarias, S; Ullaland, O; Uvarov, V; Valenti, G; Vallazza, E; Van der Velde, C; van Apeldoorn, G W; van Dam, P; Van Doninck, W K; Van Eldik, J; Van Lysebetten, A; Van Vulpen, I B; Vassilopoulos, N; Vegni, G; Ventura, L; Venus, W A; Verbeure, F; Verlato, M; Vertogradov, L S; Verzi, V; Vilanova, D; Vitale, L; Vlasov, E; Vodopyanov, A S; Vollmer, C F; Voulgaris, G; Vrba, V; Wahlen, H; Walck, C; Weiser, C; Wicke, D; Wickens, J H; Wilkinson, G R; Winter, M; Witek, M; Wolf, G; Yi, J; Yushchenko, O P; Zaitsev, A; Zalewska-Bak, A; Zalewski, Piotr; Zavrtanik, D; Zevgolatakos, E; Zimin, N I; Zucchelli, G C; Zumerle, G

    1999-01-01

    Infrared and collinear safe event shape distributions and their mean values are determined using the data taken at ve di erent centre of mass energies above $M_Z$ with the DELPHI detector at LEP. From the event shapes, the strong coupling $\\alpha_s$ is extracted in $O(\\alpha^2_s)$, NLLA and a combined scheme using hadronisation corrections evaluated with fragmentation model generators as well as using an analytical power ansatz. Comparing these measurements to those obtained at MZ, the energy dependence (running) of $\\alpha_s$ is accessible. The logarithmic energy slope of the inverse strong coupling is measured to be $d\\alpha_{s}^{-1}/d log(E_{cm}) = 1.39 \\pm 0.34(stat) \\pm 0.17(syst)$, in good agreement with the QCD expectation of 1.27.

  13. Alpha oscillations correlate with the successful inhibition of unattended stimuli.

    Science.gov (United States)

    Händel, Barbara F; Haarmeier, Thomas; Jensen, Ole

    2011-09-01

    Because the human visual system is continually being bombarded with inputs, it is necessary to have effective mechanisms for filtering out irrelevant information. This is partly achieved by the allocation of attention, allowing the visual system to process relevant input while blocking out irrelevant input. What is the physiological substrate of attentional allocation? It has been proposed that alpha activity reflects functional inhibition. Here we asked if inhibition by alpha oscillations has behavioral consequences for suppressing the perception of unattended input. To this end, we investigated the influence of alpha activity on motion processing in two attentional conditions using magneto-encephalography. The visual stimuli used consisted of two random-dot kinematograms presented simultaneously to the left and right visual hemifields. Subjects were cued to covertly attend the left or right kinematogram. After 1.5 sec, a second cue tested whether subjects could report the direction of coherent motion in the attended (80%) or unattended hemifield (20%). Occipital alpha power was higher contralateral to the unattended side than to the attended side, thus suggesting inhibition of the unattended hemifield. Our key finding is that this alpha lateralization in the 20% invalidly cued trials did correlate with the perception of motion direction: Subjects with pronounced alpha lateralization were worse at detecting motion direction in the unattended hemifield. In contrast, lateralization did not correlate with visual discrimination in the attended visual hemifield. Our findings emphasize the suppressive nature of alpha oscillations and suggest that processing of inputs outside the field of attention is weakened by means of increased alpha activity.

  14. Alpha Blockers

    Science.gov (United States)

    ... quickly, but their effects last only a few hours. Long-acting medications take longer to work, but their effects last longer. Which alpha blocker is best for you depends on your health and the condition being treated. Alpha blockers are ...

  15. [Acetylcholine activation of alpha-ketoglutarate oxidation in liver mitochondria].

    Science.gov (United States)

    Shostakovskaia, I V; Doliba, N M; Gordiĭ, S K; Babskiĭ, A M; Kondrashova, M N

    1986-01-01

    Activation of alpha-ketoglutarate oxidation in the rat liver mitochondria takes place 15 and 30 min after intraperitoneal injection of acetyl choline. This mediator in doses of 25, 50 and 100 micrograms per 100 g of body weight causes a pronounced stimulation of phosphorylation respiration rate and calcium capacity of mitochondria with alpha-ketoglutarate oxidation. Acetyl choline is found to have a moderate inhibitory action on oxidation of lower (physiological) concentrations of succinate. Its stimulating action on alpha-ketoglutarate oxidation is associated with activation of M-cholinoreceptors; atropine, a choline-blocker, removes completely this effect. It is supposed that alpha-ketoglutarate and succinate are included into the composition of two reciprocal hormonal-substrate nucleotide systems.

  16. PREVAIL-EPL alpha tool electron optics subsystem

    Science.gov (United States)

    Pfeiffer, Hans C.; Dhaliwal, Rajinder S.; Golladay, Steven D.; Doran, Samuel K.; Gordon, Michael S.; Kendall, Rodney A.; Lieberman, Jon E.; Pinckney, David J.; Quickle, Robert J.; Robinson, Christopher F.; Rockrohr, James D.; Stickel, Werner; Tressler, Eileen V.

    2001-08-01

    The IBM/Nikon alliance is continuing pursuit of an EPL stepper alpha tool based on the PREVAIL technology. This paper provides a status report of the alliance activity with particular focus on the Electron Optical Subsystem developed at IBM. We have previously reported on design features of the PREVAIL alpha system. The new state-of-the-art e-beam lithography concepts have since been reduced to practice and turned into functional building blocks of a production level lithography tool. The electron optical alpha tool subsystem has been designed, build, assembled and tested at IBM's Semiconductor Research and Development Center (SRDC) in East Fishkill, New York. After demonstrating subsystem functionality, the electron optical column and all associated control electronics hardware and software have been shipped during January 2001 to Nikon's facility in Kumagaya, Japan, for integration into the Nikon commercial e-beam stepper alpha tool. Early pre-shipment results obtained with this electron optical subsystem are presented.

  17. Project Longshot: A mission to Alpha Centauri

    Science.gov (United States)

    West, Curtis; Chamberlain, Sally; Pagan, Neftali; Stevens, Robert

    1989-01-01

    Project Longshot, an exercise in the Advanced Design Program for Space, had as its destination Alpha Centauri, the closest star system to our own solar system. Alpha Centauri, a trinary star system, is 4.34 light years from earth. Although Project Longshot is impossible based on existing technologies, areas that require further investigation in order to make this feat possible are identified. Three areas where advances in technology are needed are propulsion, data processing for autonomous command and control functions, and reliability. Propulsion, possibly by antimatter annihilation; navigation and navigation aids; reliable hardware and instruments; artificial intelligence to eliminate the need for command telemetry; laser communication; and a reliable, compact, and lightweight power system that converts energy efficiently and reliably present major challenges. Project Longshot promises exciting advances in science and technology and new information concerning the universe.

  18. Uranium analysis in Cypriot groundwaters by total alpha-radiometry and alpha-spectroscopy

    International Nuclear Information System (INIS)

    Efstathiou, Maria; Kiliari, Tasoula; Pashalidis, Ioannis

    2011-01-01

    Two different alpha-radiometric methods (e.g. alpha-spectroscopy and alpha-particle counting) have been applied to the determination of uranium in Cypriot groundwater samples after separation of the radionuclides by cation exchange using Chelex-100 and its electrodeposition on stainless steel planchettes. The data obtained were compared to show the advantages and disadvantages of the two radiometric methods, determine the alpha-radioactivity concentration and the radiation dose associated with the use of the studied groundwaters. Calibration of the methods was performed by means of uranium standard solutions and the corresponding data were used to evaluate linear range, detector efficiency, detection limits, value of the information obtained, and time of analysis of the methods. Comparison of the data obtained from calibration and natural sample measurements has shown that alpha-particle counting with a simple alpha-radiometer (equipped with a semiconductor detector) may offer only an activity value and not detailed information about the isotopic composition but it is the fastest method and the method of choice if only a screening method for the alpha-radioactivity measurement is required. Based on the alpha-radioactivity data, the corresponding radiation dose was estimated for situations where the groundwaters are used for drinking water purposes.

  19. Increased severity of experimental autoimmune encephalomyelitis, chronic macrophage/microglial reactivity, and demyelination in transgenic mice producing tumor necrosis factor-alpha in the central nervous system

    DEFF Research Database (Denmark)

    Taupin, V; Renno, T; Bourbonnière, L

    1997-01-01

    are a target of immune attack. TNF-alpha also regulates macrophage activity which could contribute to autoimmune inflammation. We have expressed TNF-alpha at disease-equivalent levels in the central nervous system of transgenic mice, using a myelin basic protein (MBP) promoter. These mice were normal...

  20. Development and testing of prototype alpha waste incinerator off-gas systems

    International Nuclear Information System (INIS)

    Freed, E.J.; Becker, G.W.

    1982-01-01

    A test program is in progress at Savannah River Laboratory (SRL) to confirm and develop incinerator design technology for an SRP production Alpha Waste Incinerator (AWI) to be built in the mid-1980's. The Incinerator Components Test Facility (ICTF) is a full-scale (5 kg/h), electrically heated, controlled-air prototype incinerator built to burn nonradioactive solid waste. The incinerator has been operating successfully at SRL since March 1979 and has met or exceeded all design criteria. During the first 1-1/2 years of operation, liquid scrubbers were used to remove particulates and hydrochloric acid from the incinerator exhaust gases. A dry off-gas system is currently being tested to provide data to Savannah River Plant's proposed AWI

  1. Influence of fast alpha diffusion and thermal alpha buildup on tokamak reactor performance

    International Nuclear Information System (INIS)

    Uckan, N.A.; Tolliver, J.S.; Houlberg, W.A.; Attenberger, S.E.

    1988-01-01

    The effect of fast alpha diffusion and thermal alpha accumulation on the confinement capability of a candidate Engineering Test Reactor plasma (Tokamak Ignition/Burn Experimental Reactor) in achieving ignition and steady-state driven operation has been assessed using both global and 1-1/2-dimensional transport models. Estimates are made of the threshold for radial diffusion of fast alphas and thermal alpha buildup. It is shown that a relatively low level of radial transport, when combined with large gradients in the fast alpha density, leads to a significant radial flow with a deleterious effect on plasma performance. Similarly, modest levels of thermal alpha concentration significantly influence the ignition and steady-state burn capability

  2. Non-LTE effects on the strength of the Lyman edge in quasar accretion disks

    Science.gov (United States)

    Stoerzer, H.; Hauschildt, P. H.; Allard, F.

    1994-01-01

    We have calculated UV/EUV (300 A which is less than or equal to lambda which is less than or equal to 1500 A) continuous energy distributions of accretion disks in the centers of active galactic nuclei (AGNs) for disk luminosities in the range 0.1 L(sub Edd) less than or equal to L(sub acc) less than 1.0 L(sub Edd) and central masses ranging from 10(exp 8) solar mass to 10(exp 9) solar mass. The vertical gas pressure structure of the disk and the disk height are obtained analytically; the temperature stratification and the resulting continuum radiation fields are calculated numerically. We have included non-Local Thermodynamic Equilibrium (LTE) effects of both the ionization equilibrium and the level populations of hydrogen and helium. We show that these non-LTE effects reduce the strength of the Lyman edge when comapred to the LTE case. In non-LTE we find that the edge can be weakly in emission or absorption for disks seen face-on, depending on the disk parameters.

  3. Detection of baryon acoustic oscillations in the Lyman-α forests of BOSS quasar spectra

    International Nuclear Information System (INIS)

    Delubac, Timothee

    2013-01-01

    Baryon acoustic oscillations (BAO) form a standard ruler that can be used to constrain different cosmological models. This thesis reports the first measurement of the BAO feature in the correlation function of the transmitted flux fraction in the Lyman-α forests of high redshift quasars. This detection uses 89322 quasar spectra measured by the Baryon Oscillation Spectroscopic Survey (BOSS) of the third generation of the Sloan Digital Sky Survey (SDSS-III). Redshift of used quasars belong to the range 2.1≤z≤3.5. A peak in the correlation function is seen at 1.043"+"0"."0"2"1_-_0_._0_2_0 times the expected BAO peak position for a concordance ΛCDM model. In addition this thesis presents a new method of quasar selection through their variability. This method is applied to the Stripe 82 region where an important number of multi-epoch photometric data is available. On this region it achieves a quasar density of 30 deg"-"2 to be compared with the 18 deg"-"2 of usual color selections. (author) [fr

  4. Alpha scintillation radon counting

    International Nuclear Information System (INIS)

    Lucas, H.F. Jr.

    1977-01-01

    Radon counting chambers which utilize the alpha-scintillation properties of silver activated zinc sulfide are simple to construct, have a high efficiency, and, with proper design, may be relatively insensitive to variations in the pressure or purity of the counter filling. Chambers which were constructed from glass, metal, or plastic in a wide variety of shapes and sizes were evaluated for the accuracy and the precision of the radon counting. The principles affecting the alpha-scintillation radon counting chamber design and an analytic system suitable for a large scale study of the 222 Rn and 226 Ra content of either air or other environmental samples are described. Particular note is taken of those factors which affect the accuracy and the precision of the method for monitoring radioactivity around uranium mines

  5. Alpha detection in pipes using an inverting membrane scintillator

    International Nuclear Information System (INIS)

    Kendrick, D.T.; Cremer, C.D.; Lowry, W.; Cramer, E.

    1995-01-01

    Characterization of surface alpha emitting contamination inside enclosed spaces such as piping systems presents an interesting radiological measurement challenge. Detection of these alpha particles from the exterior of the pipe is impossible since the alpha particles are completely absorbed by the pipe wall. Traditional survey techniques, using hand-held instruments, simply can not be used effectively inside pipes. Science and Engineering Associates, Inc. is currently developing an enhancement to its Pipe Explorer trademark system that will address this challenge. The Pipe Explorer trademark uses a unique sensor deployment method where an inverted tubular membrane is propagated through complex pipe runs via air pressure. The inversion process causes the membrane to fold out against the pipe wall, such that no part of the membrane drags along the pipe wall. This deployment methodology has been successfully demonstrated at several DOE sites to transport specially designed beta and gamma scintillation detectors into pipes ranging in length up to 250 ft. The measurement methodology under development overcomes the limitations associated with conventional hand-held survey instruments by remotely emplacing an alpha scintillator in direct contact with the interior pipe surface over the entire length to be characterized. This is accomplished by incorporating a suitable scintillator into the otherwise clear membrane material. Alpha particles emitted from the interior pipe surface will intersect the membrane, resulting in the emission of light pulses from the scintillator. A photodetector, towed by the inverting membrane, is used to count these light pulses as a function of distance into the pipe, thereby producing a log of the surface alpha contamination levels. It is anticipated that the resulting system will be able to perform measurements in pipes as small as two inches in diameter, and several hundred feet in length

  6. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    International Nuclear Information System (INIS)

    Sardini, Paul; Angileri, Axel; Descostes, Michael; Duval, Samuel; Oger, Tugdual; Patrier, Patricia; Rividi, Nicolas; Siitari-Kauppi, Marja; Toubon, Hervé; Donnard, Jérôme

    2016-01-01

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as 226 Ra, are complicated to localize in geo-materials. Because of its high specific activity, 226 Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  7. Quantitative autoradiography of alpha particle emission in geo-materials using the Beaver™ system

    Energy Technology Data Exchange (ETDEWEB)

    Sardini, Paul; Angileri, Axel [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Descostes, Michael [AREVA Mines, R& D Department, Paris (France); Duval, Samuel; Oger, Tugdual [AI4R SAS, Nantes (France); Patrier, Patricia [IC2MP Equipe HydrASA, 6 Rue Michel Brunet, B35, TSA 51106 Poitiers Cedex 9 (France); Rividi, Nicolas [Service Camparis, Université Pierre et Marie Curie, Paris (France); Siitari-Kauppi, Marja [Radiochemistry Laboratory, University of Helsinki, Helsinki (Finland); Toubon, Hervé [AREVA Mines, R& D Department, Paris (France); Donnard, Jérôme [AI4R SAS, Nantes (France)

    2016-10-11

    In rocks or artificial geo-materials, radioactive isotopes emitting alpha particles are dispersed according to the mineralogy. At hand specimen scale, the achievement of quantitative chemical mapping of these isotopes takes on a specific importance. Knowledge of the distribution of the uranium and thorium series radionuclides is of prime interest to several disciplines, from the geochemistry of uranium deposits, to the dispersion of uranium mill tailings in the biosphere. The disequilibrium of these disintegration chains is also commonly used for dating. However, some prime importance isotopes, such as {sup 226}Ra, are complicated to localize in geo-materials. Because of its high specific activity, {sup 226}Ra is found in very low concentrations (~ppq), preventing its accurate localization in rock forming minerals. This paper formulates a quantitative answer to the following question: at hand specimen scale, how can alpha emitters in geo-materials be mapped quantitatively? In this study, we tested a new digital autoradiographic method (called the Beaver™) based on a Micro Patterned Gaseous Detector (MPGD) in order to quantitatively map alpha emission at the centimeter scale rock section. Firstly, for two thin sections containing U-bearing minerals at secular equilibrium, we compared the experimental and theoretical alpha count rates, measured by the Beaver™ and calculated from the uranium content, respectively. We found that they are very similar. Secondly, for a set of eight homemade standards made up of a mixture of inactive sand and low-radioactivity mud, we compared the count rates obtained by the Beaver™ and by an alpha spectrometer. The results indicate (i) a linearity between both count rates, and (ii) that the count obtained by the Beaver™ can be estimated from the count obtained by the alpha spectrometry using a factor of 0.82.

  8. [Age-related change in the alpha-tocopherolquinone/alpha-tocopherol ratio in the rat erythrocyte membrane].

    Science.gov (United States)

    Yanagawa, K; Takeda, H; Matsumiya, T; Takasaki, M

    1999-05-01

    alpha-Tocopherol (alpha-Toc), a lipophilic phenolic antioxidant that is localized mainly in the biomembrane, protects cells against oxidation-associated cytotoxicity by prevention of membrane lipid peroxidation, maintenance of the redox balance intracellular thiols and stabilization of the membrane structure. We investigated the age-related changes in redox dynamics of alpha-Toc in plasma and erythrocyte membrane of an elderly (66 weeks old) and young group (10 weeks old). Total, alpha-, beta + gamma-, delta-Toc and alpha-tocopherolquinone (alpha-TocQ) in plasma and erythrocyte membrane were determined by high-performance liquid chromatography (HPLC) with a series of multiple coulometric working electrodes (CWE). Rat venous blood sample was divided into plasma and erythrocyte layers by centrifugation, and then erythrocyte membrane sample was prepared according to the method of Dodge et al. under a stream of nitrogen. In plasma, total and alpha-Toc concentrations were increased, and beta + gamma-, delta-Toc and alpha-TocQ concentrations were decreased age-dependently. In the erythrocyte membrane, total, alpha-TocQ concentrations and three fractions of tocopherols decreased age-dependently. Also, a decrease in the alpha-TocQ/alpha-Toc ratio in erythrocyte membrane was observed in the elderly group. These findings suggest that the alpha-Toc uptake in erythrocyte membrane and utilization rate of alpha-Toc in erythrocyte membrane decline age-dependently. This decline may promote membrane lipid peroxidation. alpha-Toc redox dynamics in erythrocyte membrane were useful to investigate the pathophysiology of aging mechanisms related to oxidative stress.

  9. Effect of alpha particles on Toroidal Alfven Eigenmodes

    International Nuclear Information System (INIS)

    Berk, H.L.

    1992-11-01

    An overview is given of the analytic structure for the linear theory of the Toroidal Alfven Eigenmode (TAE), where multiple gap structures occur. A discussion is given of the alpha particle drive and the various dissipation mechanisms that can stabilize the system. A self-consistent calculation of the TAE mode, for a low-beta high-aspect-ratio plasma, indicates that though the alpha particle drive is comparable to the dissipation mechanisms, overall stability is still achieved for ignited ITER-like plasma. A brief discussion is given of the nonlinear theory for the TAE mode and how nonlinear alpha particle dynamics can be treated by mapping methods

  10. Particularisation of Alpha Contamination using CR-39 Track Detectors

    International Nuclear Information System (INIS)

    Zakia, M.F.; El-Shaer, Y.H.

    2008-01-01

    Solid-state nuclear track detectors have found wide use in various domains of science and technology, e.g. in environmental experiments. The measurement of alpha activity on sources in an environment, such as air is not easy because of short penetration range of the alpha particles. Furthermore, the measurement of alpha activity by most gas ionization detectors suffers from the high background induced by the accompanying gamma radiation. Solid State Nuclear Track Detectors (SSNTDs) have been used successfully as detecting devices as passive system to detect the alpha contamination different surfaces. This work presents the response of CR-39 (for two types) to alpha particles from two sources, 238 Pu with energy 5 MeV and 241 Am with energy 5.4 MeV. The methods of etching and counting are investigated, along with the achievable linearity, efficiency and reproducibility. The sensitivity to low activity and energy resolution are studied

  11. Applications of alpha particles detectors made of nitrocellulose film

    International Nuclear Information System (INIS)

    Segovia, N.; Salinas, B.; Pineda, H.

    1978-01-01

    We describe the experiments realized in order to probe the response of the alpha particles detectors manufactured in our laboratory and their suitability to some important applications. The detection system is a nitrocellulose film which register the transit of the charged particles. The traces left by the particles during their transit are manifested through a controlled chemical attack and counted after that with a microscope. This monitor system was utilized in the following applications: 1) uranium prospection 2) alpha autoradiography 4) determination of air pollution by alpha emitters. The results which were obtained are satisfactory and in spite that in these first applications only qualitative measurements were made the method could be used for quantitative determinations when we will have a better knowledge of the effect of factors which are not under our control. (author)

  12. The effect of stellar evolution uncertainties on the rest-frame ultraviolet stellar lines of C IV and He II in high-redshift Lyman-break galaxies

    Science.gov (United States)

    Eldridge, John J.; Stanway, Elizabeth R.

    2012-01-01

    Young, massive stars dominate the rest-frame ultraviolet (UV) spectra of star-forming galaxies. At high redshifts (z > 2), these rest-frame UV features are shifted into the observed-frame optical and a combination of gravitational lensing, deep spectroscopy and spectral stacking analysis allows the stellar population characteristics of these sources to be investigated. We use our stellar population synthesis code Binary Population and Spectral Synthesis (BPASS) to fit two strong rest-frame UV spectral features in published Lyman-break galaxy spectra, taking into account the effects of binary evolution on the stellar spectrum. In particular, we consider the effects of quasi-homogeneous evolution (arising from the rotational mixing of rapidly rotating stars), metallicity and the relative abundance of carbon and oxygen on the observed strengths of He IIλ1640 Å and C IVλ1548, 1551 Å spectral lines. We find that Lyman-break galaxy spectra at z ˜ 2-3 are best fitted with moderately sub-solar metallicities, and with a depleted carbon-to-oxygen ratio. We also find that the spectra of the lowest metallicity sources are best fitted with model spectra in which the He II emission line is boosted by the inclusion of the effect of massive stars being spun-up during binary mass transfer so these rapidly rotating stars experience quasi-homogeneous evolution.

  13. Identification of a novel bile acid in swans, tree ducks, and geese: 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid.

    Science.gov (United States)

    Kakiyama, Genta; Iida, Takashi; Goto, Takaaki; Mano, Nariyasu; Goto, Junichi; Nambara, Toshio; Hagey, Lee R; Schteingart, Claudio D; Hofmann, Alan F

    2006-07-01

    By HPLC, a taurine-conjugated bile acid with a retention time different from that of taurocholate was found to be present in the bile of the black-necked swan, Cygnus melanocoryphus. The bile acid was isolated and its structure, established by (1)H and (13)C NMR and mass spectrometry, was that of the taurine N-acyl amidate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid. The compound was shown to have chromatographic and spectroscopic properties that were identical to those of the taurine conjugate of authentic 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid, previously synthesized by us from ursodeoxycholic acid. By HPLC, the taurine conjugate of 3alpha,7alpha,15alpha-trihydroxy-5beta-cholan-24-oic acid was found to be present in 6 of 6 species in the subfamily Dendrocygninae (tree ducks) and in 10 of 13 species in the subfamily Anserinae (swans and geese) but not in other subfamilies in the Anatidae family. It was also not present in species from the other two families of the order Anseriformes. 3alpha,7alpha,15alpha-Trihydroxy-5beta-cholan-24-oic acid is a new primary bile acid that is present in the biliary bile acids of swans, tree ducks, and geese and may be termed 15alpha-hydroxy-chenodeoxycholic acid.

  14. [Engineering of a System for the Production of Mutant Human Alpha-Fetoprotein in the Methylotrophic Yeast Pichia pastoris].

    Science.gov (United States)

    Morozkina, E V; Vavilova, E A; Zatsepin, S S; Klyachko, E V; Yagudin, T A; Chulkin, A M; Dudich, I V; Semenkova, L N; Churilova, I V; Benevolenskii, S V

    2016-01-01

    A system for the production of mutant recombinant human alpha-fetoprotein (rhAFPO) lacking the glycosylation site has been engineered in the yeast Pichia pastoris. A strain of the methylotrophic yeast Pichia pastoris GS 115/pPICZ?A/rhAFP0, which produces unglycosylated rhAFPO and secretes it to the culture medium, has been constructed. Optimization and scale-up of the fermentation technology have resulted in an increase in the rhAFP0 yield to 20 mg/L. A scheme of isolation and purification of biologically active rhAFP0 has been developed. The synthesized protein has the antitumor activity, which is analogous to the activity of natural human embryonic alpha-fetoprotein.

  15. Alpha-2 adrenergic stimulation triggers Achilles tenocyte hypercellularity: Comparison between two model systems.

    Science.gov (United States)

    Backman, L J; Andersson, G; Fong, G; Alfredson, H; Scott, A; Danielson, P

    2013-12-01

    The histopathology of tendons with painful tendinopathy is often tendinosis, a fibrosis-like condition of unclear pathogenesis characterized by tissue changes including hypercellularity. The primary tendon cells (tenocytes) have been shown to express adrenoreceptors (mainly alpha-2A) as well as markers of catecholamine production, particularly in tendinosis. It is known that adrenergic stimulation can induce proliferation in other cells. The present study investigated the effects of an exogenously administered alpha-2 adrenergic agonist in an established in vivo Achilles tendinosis model (rabbit) and also in an in vitro human tendon cell culture model. The catecholamine producing enzyme tyrosine hydroxylase and the alpha-2A-adrenoreceptor (α2A AR) were expressed by tenocytes, and alpha-2 adrenergic stimulation had a proliferative effect on these cells, in both models. The proliferation was inhibited by administration of an α2A AR antagonist, and the in vitro model further showed that the proliferative alpha-2A effect was mediated via a mitogenic cell signaling pathway involving phosphorylation of extracellular-signal-regulated kinases 1 and 2. The results indicate that catecholamines produced by tenocytes in tendinosis might contribute to the proliferative nature of the pathology through stimulation of the α2A AR, pointing to a novel target for future therapies. The study furthermore shows that animal models are not necessarily required for all aspects of this research. © 2013 The Authors. Scand J Med Sci Sports published by John Wiley & Sons Ltd.

  16. An advanced computer-controlled automatic alpha-beta air sample counter

    International Nuclear Information System (INIS)

    Howell, W.P.; Bruinekool, D.J.; Stapleton, E.E.

    1984-01-01

    An improved computer-controlled automatic alpha-beta air sample counter was developed, based upon an earlier automatic air sample counter design. The system consists of an automatic sample changer, an electronic counting system utilizing a large silicon diode detector, a small desk-type microcomputer, a high-speed matrix printer and the necessary data interfaces. The system is operated by commands from the keyboard and programs stored on magnetic tape cassettes. The programs provide for background counting, Chi 2 test, radon subtraction and sample counting for sample periods of one day to one week. Output data are printed by the matrix printer on standard multifold paper. The data output includes gross beta, gross alpha and plutonium results. Data are automatically corrected for background, counter efficiency, and in the gross alpha and plutonium channels, for the presence of radon

  17. Angular distributions of the alpha particle production in the 7Li+144Sm system at near-barrier energies

    International Nuclear Information System (INIS)

    Carnelli, P F F; Arazi, A; Capurro, O A; Niello, J O Fernández; Heimann, D Martinez; Pacheco, A J; Cardona, M A; De Barbará, E; Figueira, J M; Hojman, D L; Martí, G V; Negri, A E

    2015-01-01

    We have studied the production of alpha particles in reactions induced by 7 Li projectiles on a 144 Sm target at bombarding energies of 18, 24 and 30 MeV over the 15°-140° angular range. The purpose of the investigation has been to determine the contribution of different mechanisms in reactions that involve weakly bound projectiles. We have included in our analysis several processes that can either directly or sequentially lead to the emission of alpha particles: complete fusion, direct transfer of 3 H, capture breakup (incomplete fusion, sequential complete fusion) and non-capture breakup. In order to distinguish alpha particles stemming from these processes it is necessary to determine the mass and charge of the reaction products and to obtain precise measurements of their energies and scattering angles over relatively wide ranges of these variables. We have done this using a detection system consisting of an ionization chamber plus three position sensitive detectors. We present results of these measurements and a preliminary interpretation based on kinematical considerations and comparisons with predictions from a statistical model. (paper)

  18. Rossi Alpha Method

    International Nuclear Information System (INIS)

    Hansen, G.E.

    1985-01-01

    The Rossi Alpha Method has proved to be valuable for the determination of prompt neutron lifetimes in fissile assemblies having known reproduction numbers at or near delayed critical. This workshop report emphasizes the pioneering applications of the method by Dr. John D. Orndoff to fast-neutron critical assemblies at Los Alamos. The value of the method appears to disappear for subcritical systems where the Rossi-α is no longer an α-eigenvalue

  19. Buffett's Alpha

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Kabiller, David; Heje Pedersen, Lasse

    Berkshire Hathaway has realized a Sharpe ratio of 0.76, higher than any other stock or mutual fund with a history of more than 30 years, and Berkshire has a significant alpha to traditional risk factors. However, we find that the alpha becomes insignificant when controlling for exposures to Betting...

  20. Sterol synthesis. A novel reductive rearrangement of an alpha,beta-unsaturated steroidal epoxide; a new chemical synthesis of 5alpha-cholest-8(14)-en-3beta, 15alpha-diol.

    Science.gov (United States)

    Parish, E J; Schroepfer, G J

    1977-04-01

    Reduction of 3beta-benzoyloxy-14alpha,15alpha-epoxy-5alpha-cholest-7-ene with either lithium triethylboro-hydride or lithium aluminum hydride (4 molar excess) gave 5-alpha-cholest-8(14)-en-3beta,15alpha-diol in high yield. Reduction of the epoxy ester with lithium triethylborodeuteride or lithium aluminum deuteride (4 molar excess) gave [7alpha-2-H]-5alpha-cholest-8(14)-en-3beta,15alpha-diol. Reduction of 2beta-benzoyloxy-14alpha,15alpha-epoxy-5alpha-cholest-7-ene with a large excess (24 molar excess) of lithium aluminum hydride gave, in addition to the expected 5alpha-cholest-8(14)-en-3beta,15alpha-diol, a significant yield (33%) of 5alpha-cholest-8(14)-en-3beta-o1. Reduction of the epoxy ester with a large excess (24 molar excess) of lithium aluminum deuteride gave [7alpha-2H]-5alpha-cholest-8(14)-en-3beta,15alpha-diol and 5alpha-cholest-8(14)-en-3beta-o1 which contained two atoms of stably bound deuterium.

  1. Drugs interacting with alpha adrenoceptors

    NARCIS (Netherlands)

    van Zwieten, P. A.

    1989-01-01

    Alpha adrenoceptors should be divided into various subtypes, comprising pre/postsynaptic and alpha 1/alpha 2-subpopulations, respectively. This classification implicates important functional differences between the various alpha-receptor subtypes, including certain differences in signal transduction

  2. Continuous air monitor for alpha-emitting aerosol particles

    International Nuclear Information System (INIS)

    McFarland, A.R.; Ortiz, C.A.; Rodgers, J.C.; Nelson, D.C.

    1991-01-01

    A new alpha continuous air monitor (CAM) sampler is being developed for use in detecting the presence of alpha-emitting aerosol particles. The effort involves design, fabrication and evaluation of systems for the collection of aerosol and for the processing of data to speciate and quantify the alpha emitters of the interest. At the present time the authors have a prototype of the aerosol sampling system and they have performed wind tunnel tests to characterize the performance of the device for different particle sizes, wind speeds, flow rates and internal design parameters. The results presented herein deal with the aerosol sampling aspects of the new CAM sampler. Wind tunnel tests show that ≥ 50% of 10 μm aerodynamic equivalent diameter (AED) particles penetrate the flow system from the ambient air to the collection filter when the flow rate is 57 L/min (2 cfm) and the wind speed is 1 m/s. The coefficient of variation of deposits of 10 μm AED aerosol particles on the collection filter is 7%. An inlet fractionator for removing high mobility background aerosol particles has been designed and successfully tested. The results show that it is possible to strip 95% of freshly formed radon daughters and 33% of partially aged radon daughters from the aerosol sample. This approach offers the opportunity to improve the signal-to-noise ratio in the alpha energy spectrum region of interest thereby enhancing the performance of background compensation algorithms

  3. Absolute generalized oscillator strength for the Lyman--Birge--Hopfield band of N2 as determined by high energy electron impact spectroscopy

    International Nuclear Information System (INIS)

    Wong, T.C.; Lee, J.S.; Wellenstein, H.F.; Bonham, R.A.

    1975-01-01

    The absolute generalized oscillator strength for the dipole forbidden quadrupole allowed Lyman--Birge--Hopfield band a 1 Pi/subg/ reverse arrow X 1 Σ + /subg/ in molecular nitrogen at an energy loss of 9.35 eV is observed by electron impact spectroscopy using 25 keV electrons over the momentum transfer range 0.04less than or equal toK 2 less than or equal to10 a.u. The results agree in the zero angle (zero momentum transfer) limit with the previous observations of Skerbele and Lassettre, but are in disagreement with previous theoretical and experimental results for K 2 >0.5. (auth)

  4. Analyses of Alpha-Alpha Elastic Scattering Data in the Energy Range 140 - 280 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Shehadeh, Zuhair F. [Taif University, Taif (Saudi Arabia)

    2017-01-15

    The differential and the reaction cross-sections for 4He-4He elastic scattering data have been nicely obtained at four energies ranging from 140 MeV to 280 MeV (lab system), namely, 140, 160, 198 and 280 MeV, by using a new optical potential with a short-range repulsive core. The treatment has been handled relativistically as υ/c > 0.25 for the two lower energies and υ/c > 0.31 for the two higher ones. In addition to explaining the elastic angular distributions, the adopted potentials accounted for the structure that may exist at angles close to 90◦ , especially for the 198 and the 280-MeV incident energies. No renormalization has been used, and all our potential parameters are new. The necessity of including a short-range repulsive potential term in our real nuclear potential part has been demonstrated. Our results contribute to solving a long-standing problem concerning the nature of the alpha-alpha potential. This is very beneficial in explaining unknown alpha-nucleus and nucleus-nucleus relativistic reactions by using the cluster formalism.

  5. Alpha detection for decontamination and decommissioning: Results and possibilities

    International Nuclear Information System (INIS)

    MacArthur, D.

    1995-01-01

    Alpha detectors based on the long-range alpha detection (LRAD) technology have numerous uses, both potential and demonstrated, in facility D ampersand D. These monitors operate by detecting the ions created by alpha particles interacting with ambient air. Thus, detection is not limited by the short range of the alpha particle and no window is required between the contamination and the detection region. These properties make LRAD-based detectors ideal for operation in field environments where complex objects to be monitored are the norm and reliability is crucial. Three monitors of particular interest in D ampersand D operations are the building surface monitor, the internal volume monitor for use on the inner surfaces of pipes, ducts, and tanks, and the conveyer belt monitor for concrete rubble and structural steel. Surface monitors have been used extensively, both in laboratory and field environments, internal volume monitors have been tested in the laboratory, and the conveyer system is still a conceptual design. These monitors and related applications demonstrate the utility of LRAD-based monitors for D ampersand D operations as well as exploring some of the new ways that fieldable monitoring systems can be used for D ampersand D. Ion collection sensing technology can be used to solve many of the alpha detection problems unique to the D ampersand D field

  6. Screening alpha-glucosidase and alpha-amylase inhibitors from natural compounds by molecular docking in silico.

    Science.gov (United States)

    Jhong, Chien-Hung; Riyaphan, Jirawat; Lin, Shih-Hung; Chia, Yi-Chen; Weng, Ching-Feng

    2015-01-01

    The alpha-glucosidase inhibitor is a common oral anti-diabetic drug used for controlling carbohydrates normally converted into simple sugars and absorbed by the intestines. However, some adverse clinical effects have been observed. The present study seeks an alternative drug that can regulate the hyperglycemia by down-regulating alpha-glucosidase and alpha-amylase activity by molecular docking approach to screen the hyperglycemia antagonist against alpha-glucosidase and alpha-amylase activities from the 47 natural compounds. The docking data showed that Curcumin, 16-hydroxy-cleroda-3,13-dine-16,15-olide (16-H), Docosanol, Tetracosanol, Antroquinonol, Berberine, Catechin, Quercetin, Actinodaphnine, and Rutin from 47 natural compounds had binding ability towards alpha-amylase and alpha-glucosidase as well. Curcumin had a better biding ability of alpha-amylase than the other natural compounds. Analyzed alpha-glucosidase activity reveals natural compound inhibitors (below 0.5 mM) are Curcumin, Actinodaphnine, 16-H, Quercetin, Berberine, and Catechin when compared to the commercial drug Acarbose (3 mM). A natural compound with alpha-amylase inhibitors (below 0.5 mM) includes Curcumin, Berberine, Docosanol, 16-H, Actinodaphnine/Tetracosanol, Catechin, and Quercetin when compared to Acarbose (1 mM). When taken together, the implication is that molecular docking is a fast and effective way to screen alpha-glucosidase and alpha-amylase inhibitors as lead compounds of natural sources isolated from medicinal plants. © 2015 International Union of Biochemistry and Molecular Biology.

  7. Continuous monitoring for airborne alpha emitters in a dusty environment

    International Nuclear Information System (INIS)

    Seiler, F.A.; Newton, G.J.; Guilmette, R.A.

    1988-01-01

    Disposal of radioactive wastes in underground facilities requires continuous monitoring for airborne radioactive materials, both on the surface and underground. In addition to a natural background of nonradioactive and radioactive aerosols, there may be a sizeable dust contribution from ongoing work such as mining and vehicular traffic. In the monitoring of alpha-emitting radionuclides, these aerosols may lead to self-absorption in the source and a deterioration of the energy spectrum of the detected alpha particles. In this paper, the influence of a realistic background aerosol on the performance of an alpha monitoring system is evaluated theoretically. It is shown that depositing alpha emitters and background aerosol on a surface for counting leads rapidly to a considerable loss of counts, a deterioration of the alpha spectra, an eventual saturation of the count rates, and interference from the natural background of Rn daughters

  8. Long-range alpha detector

    International Nuclear Information System (INIS)

    MacArthur, D.W.; McAtee, J.L.

    1991-01-01

    Historically, alpha-particle and alpha-contamination detectors have been limited by the very short range of alpha particles in air and by relatively poor sensitivity even if the particles are intercepted. Alpha detectors have had to be operated in a vacuum or in close proximity to the source if reasonable efficiency is desired. Alpha particles interact with the ambient air, producing ionization in the air at the rate of ∼30,000 ion pairs per mega-electron-volt of alpha energy. These charges can be transported over significant distances (several meters) in a moving current of air generated by a small fan. An ion chamber located in front of the fan measures the current carried by the moving ions. The long-range alpha detector (LRAD) offers several advantages over more traditional alpha detectors. First and foremost, it can operate efficiently even if the contamination is not easily accessible. Second, ions generated by contamination in crevices and other unmonitorable locations can be detected if the airflow penetrates those areas. Third, all of the contamination on a large surface will generate ions that can be detected in a single detector; hence, the detector's sensitivity to distributed sources is not limited by the size of the probe. Finally, a simple ion chamber can detect very small electric currents, making this technique potentially quite sensitive

  9. Brain Computer Interface-Controlling Devices Utilizing The Alpha Brain Waves

    Directory of Open Access Journals (Sweden)

    Rohan Hundia

    2015-01-01

    Full Text Available Abstract This paper describes the development and testing of an interface system whereby one can control external devices by voluntarily controlling alpha waves that is through eye movement. Such a system may be used for the control of prosthetics robotic arms and external devices like wheelchairs using the alpha brain waves and the Mu rhythm. The response generated through the movement of the eye detecting and controlling the amplitude of the alpha brain waves is interfaced and processed to control Robotic systems and smart home control. In order to measure the response of alpha waves over different lobes of the brain initially I measured these signals over 32 regions using silver chloride plated electrodes. By the opening and the closure of the eyes and the movement in the up-down left-right directions and processing these movements measuring them over the occipital region I was able to differentiate the amplitude of the alpha waves generated due to these several movements. In the First session testing period subjects were asked to close and open their eyes and they were able to control limited movements of a Robot and a prosthetic arm. In the Second 2session the movement of the eyes was also considered left-right up-down along with the opening and closure during this time span they were able to control more dimensions of the robot several devices at the same time using different eye movements.

  10. Contributions to the study of heavy and superheavy nuclei stability in alpha-decay

    International Nuclear Information System (INIS)

    Silisteanu, I.

    1978-01-01

    Alpha-decay is treated in this work on the complete analogy of transfer reactions by means of nuclear shell models with continuous spectrum nucleons. Certain phenomenologically obtained or microscope evaluated data on low energy interactions between alpha-particles and nuclei, when related to nuclear structure data within the unified theory of nuclear reactions, allow of an improved accuracy in determining the alpha-particle wave function as well as of an estimation of alpha-probabilities in good keeping with experimental ones. The problem of alpha lifetimes thus narrows to the resolution of some homogeneous and inhomogeneous differential equations systems including the optic potential and the alpha formfactors. (author)

  11. Benchmarking the Geant4 full system simulation of an associated alpha-particle detector for use in a D-T neutron generator.

    Science.gov (United States)

    Zhang, Xiaodong; Hayward, Jason P; Cates, Joshua W; Hausladen, Paul A; Laubach, Mitchell A; Sparger, Johnathan E; Donnald, Samuel B

    2012-08-01

    The position-sensitive alpha-particle detector used to provide the starting time and initial direction of D-T neutrons in a fast-neutron imaging system was simulated with a Geant4-based Monte Carlo program. The whole detector system, which consists of a YAP:Ce scintillator, a fiber-optic faceplate, a light guide, and a position-sensitive photo-multiplier tube (PSPMT), was modeled, starting with incident D-T alphas. The scintillation photons, whose starting time follows the distribution of a scintillation decay curve, were produced and emitted uniformly into a solid angle of 4π along the track segments of the alpha and its secondaries. Through tracking all photons and taking into account the quantum efficiency of the photocathode, the number of photoelectrons and their time and position distributions were obtained. Using a four-corner data reconstruction formula, the flood images of the alpha detector with and without optical grease between the YAP scintillator and the fiber-optic faceplate were obtained, which show agreement with the experimental results. The reconstructed position uncertainties of incident alpha particles for both cases are 1.198 mm and 0.998 mm respectively across the sensitive area of the detector. Simulation results also show that comparing with other faceplates composed of 500 μm, 300 μm, and 100 μm fibers, the 10-μm-fiber faceplate is the best choice to build the detector for better position performance. In addition, the study of the background originating inside the D-T generator suggests that for 500-μm-thick YAP:Ce coated with 1-μm-thick aluminum, and very good signal-to-noise ratio can be expected through application of a simple threshold. Copyright © 2012 Elsevier Ltd. All rights reserved.

  12. Genetic variants of the alpha-synuclein gene SNCA are associated with multiple system atrophy.

    Directory of Open Access Journals (Sweden)

    Ammar Al-Chalabi

    Full Text Available BACKGROUND: Multiple system atrophy (MSA is a progressive neurodegenerative disorder characterized by parkinsonism, cerebellar ataxia and autonomic dysfunction. Pathogenic mechanisms remain obscure but the neuropathological hallmark is the presence of alpha-synuclein-immunoreactive glial cytoplasmic inclusions. Genetic variants of the alpha-synuclein gene, SNCA, are thus strong candidates for genetic association with MSA. One follow-up to a genome-wide association of Parkinson's disease has identified association of a SNP in SNCA with MSA. METHODOLOGY/FINDINGS: We evaluated 32 SNPs in the SNCA gene in a European population of 239 cases and 617 controls recruited as part of the Neuroprotection and Natural History in Parkinson Plus Syndromes (NNIPPS study. We used 161 independently collected samples for replication. Two SNCA SNPs showed association with MSA: rs3822086 (P = 0.0044, and rs3775444 (P = 0.012, although only the first survived correction for multiple testing. In the MSA-C subgroup the association strengthened despite more than halving the number of cases: rs3822086 P = 0.0024, OR 2.153, (95% CI 1.3-3.6; rs3775444 P = 0.0017, OR 4.386 (95% CI 1.6-11.7. A 7-SNP haplotype incorporating three SNPs either side of rs3822086 strengthened the association with MSA-C further (best haplotype, P = 8.7 x 10(-4. The association with rs3822086 was replicated in the independent samples (P = 0.035. CONCLUSIONS/SIGNIFICANCE: We report a genetic association between MSA and alpha-synuclein which has replicated in independent samples. The strongest association is with the cerebellar subtype of MSA. TRIAL REGISTRATION: ClinicalTrials.gov NCT00211224.

  13. In vitro bioactivity of 17alpha-estradiol.

    Science.gov (United States)

    Sievernich, André; Wildt, Ludwig; Lichtenberg-Fraté, Hella

    2004-12-01

    A miniaturised short-term in vitro assay based on the activation of the human estrogen receptor alpha and genetically modified yeast (Saccharomyces cerevisiae) cells was performed to explore the capacity of this system to monitor the bioactivity of estrogenic compounds, particularly 17alpha- and 17beta-estradiol. Together with the human estrogen receptor (hER)-alpha plasmid, the reporter plasmid containing a yeast-optimised version of the green fluorescent protein (yEGFP) linked to three repeats of the cis-acting estrogen hormone-responsive element (ERE) were expressed in a strain being deleted in the pleiotropic drug resistance transporters Pdr5, Snq2 and Yor1, known to facilitate efflux of organic compounds including steroids and chemotherapeutics. Agonists that bind to hER in vitro trigger estrogen receptor-mediated transcriptional activation of the GFP reporter gene monitored by fluorescence emission at 535 nm. The sensitivity of the assay was tested with various 17alpha- and 17beta-estradiol concentrations, yielding a detection limit of 5 pg/ml (0.018 nM) for the agonist 17beta-E2 in solvent and in human charcoal-stripped serum using a S. cerevisiae pdr5, snq2 and yor1 mutant strain. For 17alpha-estradiol only, at approximately 1500 pg/ml a similar fluorescence response compared to 100 pg/ml 17beta-E2 was observed implicating a much weaker potency of this stereoisomer. The specificity of the system was tested by expression of a truncated hER lacking the ligand-binding domain E and by administration of the androgen, 4-androsten 3,17 dione. Both controls did not yield an increase in fluorescence emission. This fluorescence emission assay enables detection of estrogenic biological activity induced by direct agonists, such as 17beta-E2 at concentrations similar to those found in human sera or by estrogen-like chemicals.

  14. Response of noctilucent cloud brightness to daily solar variations

    Science.gov (United States)

    Dalin, P.; Pertsev, N.; Perminov, V.; Dubietis, A.; Zadorozhny, A.; Zalcik, M.; McEachran, I.; McEwan, T.; Černis, K.; Grønne, J.; Taustrup, T.; Hansen, O.; Andersen, H.; Melnikov, D.; Manevich, A.; Romejko, V.; Lifatova, D.

    2018-04-01

    For the first time, long-term data sets of ground-based observations of noctilucent clouds (NLC) around the globe have been analyzed in order to investigate a response of NLC to solar UV irradiance variability on a day-to-day scale. NLC brightness has been considered versus variations of solar Lyman-alpha flux. We have found that day-to-day solar variability, whose effect is generally masked in the natural NLC variability, has a statistically significant effect when considering large statistics for more than ten years. Average increase in day-to-day solar Lyman-α flux results in average decrease in day-to-day NLC brightness that can be explained by robust physical mechanisms taking place in the summer mesosphere. Average time lags between variations of Lyman-α flux and NLC brightness are short (0-3 days), suggesting a dominant role of direct solar heating and of the dynamical mechanism compared to photodissociation of water vapor by solar Lyman-α flux. All found regularities are consistent between various ground-based NLC data sets collected at different locations around the globe and for various time intervals. Signatures of a 27-day periodicity seem to be present in the NLC brightness for individual summertime intervals; however, this oscillation cannot be unambiguously retrieved due to inevitable periods of tropospheric cloudiness.

  15. In vitro and preclinical targeted alpha therapy for cancer

    International Nuclear Information System (INIS)

    Allen, B.J.; Rizvi, S.; Li, Y.; Tian, Z.; University of Wollongong, NSW; Ranson, M.; Russell, P.J.

    2000-01-01

    Full text: Targeted Alpha therapy (TAT) offers the potential to inhibit the growth of micrometastases by selectively killing isolated and preangiogenic clusters of cancer cells. The alpha emitting radioisotope Bi-213 is produced by generator and chelated to a cancer affined monoclonal antibody or protein to form the alpha-conjugate (AC) against melanoma, leukaemia, colorectal, bladder, breast and prostate cancers. These ACs are tested for stability, specificity and cytotoxicity. Subcutaneous inoculation of 1.5 million cells into the flanks of nude mice causes tumours to grow in all mice. The tumour growth is compared between untreated controls, nonspecific RIC and specific RIC, for local (subcutaneous) and systemic (tail vein or intraperitoneal) injection models. Results: Stable alpha-ACs can be produced which are highly specific and cytotoxic in vitro. Local TAT at 2 days post-inoculation completely prevents tumour formation for all cancers tested so far. Local TAT can also completely regress (11/12) sc melanoma but is less successful for breast and prostate cancers. Systemic TAT inhibits the growth of sc melanoma xenografts. These results point to the potential application of local TAT and systemic TAT in the management of these cancers. A phase 1 and 2 clinical trial is planned for local TAT of sc recurrent melanoma. Copyright (2000) Australasian College of Physical Scientists and Engineers in Medicine

  16. New ALPHA-2 magnet

    CERN Multimedia

    Anaïs Schaeffer

    2012-01-01

    On 21 June, members of the ALPHA collaboration celebrated the handover of the first solenoid designed for the ALPHA-2 experiment. The magnet has since been successfully installed and is working well.   Khalid Mansoor, Sumera Yamin and Jeffrey Hangst in front of the new ALPHA-2 solenoid. “This was the first of three identical solenoids that will be installed between now and September, as the rest of the ALPHA-2 device is installed and commissioned,” explains ALPHA spokesperson Jeffrey Hangst. “These magnets are designed to allow us to transfer particles - antiprotons, electrons and positrons - between various parts of the new ALPHA-2 device by controlling the transverse size of the particle bunch that is being transferred.” Sumera Yamin and Khalid Mansoor, two Pakistani scientists from the National Centre for Physics in Islamabad, came to CERN in February specifically to design and manufacture these magnets. “We had the chance to work on act...

  17. ALPHA-2: the sequel

    CERN Multimedia

    Katarina Anthony

    2012-01-01

    While many experiments are methodically planning for intense works over the long shutdown, there is one experiment that is already working at full steam: ALPHA-2. Its final components arrived last month and will completely replace the previous ALPHA set-up. Unlike its predecessor, this next generation experiment has been specifically designed to measure the properties of antimatter.   The ALPHA team lower the new superconducting solenoid magnet into place. The ALPHA collaboration is working at full speed to complete the ALPHA-2 set-up for mid-November – this will give them a few weeks of running before the AD shutdown on 17 December. “We really want to get some experience with this device this year so that, if we need to make any changes, we will have time during the long shutdown in which to make them,” says Jeffrey Hangst, ALPHA spokesperson. “Rather than starting the 2014 run in the commissioning stage, we will be up and running from the get go.&...

  18. Technical Basis for the Use of Alpha Absorption Corrections on RCF Gross Alpha Data

    International Nuclear Information System (INIS)

    Ceffalo, G.M.

    1999-01-01

    This document provides the supporting data and rationale for making absorption corrections to gross alpha data to correct alpha data for loss due to absorption in the sample matrix. For some time there has been concern that the gross alpha data produced by the Environmental Restoration Contractor Radiological Counting Facility, particularly gross alpha analysis on soils, has been biased toward low results, as no correction for self-absorption was applied to the counting data. The process was investigated, and a new methodology for alpha self-absorption has been developed

  19. Certification of model spectrometric alpha sources (MSAS) and problems of the MSAS system improvement

    International Nuclear Information System (INIS)

    Belyatskij, A.F.; Gejdel'man, A.M.; Egorov, Yu.S.; Nedovesov, V.G.; Chechev, V.P.

    1984-01-01

    Results of certification of standard spectrometric alpha sources (SSAS) of industrial production are presented: methods for certification by main radiation physical parameters: proper halfwidth of α-lines, activity of radionuclides in the source, energies of α-particle emitting sources and relative intensity of different energy α-particle groups - are analysed. The advantage for the SSAS system improvement - a set of model measures for α-radiation, a collection of interconnected data units on physical, engineering and design characteristics of SSAS, methods for their obtaining and determination, on instruments used, is considered

  20. Cloning, expression, and mapping of allergenic determinants of alphaS1-casein, a major cow's milk allergen.

    Science.gov (United States)

    Schulmeister, Ulrike; Hochwallner, Heidrun; Swoboda, Ines; Focke-Tejkl, Margarete; Geller, Beate; Nystrand, Mats; Härlin, Annika; Thalhamer, Josef; Scheiblhofer, Sandra; Keller, Walter; Niggemann, Bodo; Quirce, Santiago; Ebner, Christoph; Mari, Adriano; Pauli, Gabrielle; Herz, Udo; Valenta, Rudolf; Spitzauer, Susanne

    2009-06-01

    Milk is one of the first components introduced into human diet. It also represents one of the first allergen sources, which induces IgE-mediated allergies in childhood ranging from gastrointestinal, skin, and respiratory manifestations to severe life-threatening manifestations, such as anaphylaxis. Here we isolated a cDNA coding for a major cow's milk allergen, alphaS1-casein, from a bovine mammary gland cDNA library with allergic patients' IgE Abs. Recombinant alphaS1-casein was expressed in Escherichia coli, purified, and characterized by circular dichroism as a folded protein. IgE epitopes of alphaS1-casein were determined with recombinant fragments and synthetic peptides spanning the alphaS1-casein sequence using microarrayed components and sera from 66 cow's milk-sensitized patients. The allergenic activity of ralphaS1-casein and the alphaS1-casein-derived peptides was determined using rat basophil leukemia cells transfected with human FcepsilonRI, which had been loaded with the patients' serum IgE. Our results demonstrate that ralphaS1-casein as well as alphaS1-casein-derived peptides exhibit IgE reactivity, but mainly the intact ralphaS1-casein induced strong basophil degranulation. These results suggest that primarily intact alphaS1-casein or larger IgE-reactive portions thereof are responsible for IgE-mediated symptoms of food allergy. Recombinant alphaS1-casein as well as alphaS1-casein-derived peptides may be used in clinical studies to further explore pathomechanisms of food allergy as well as for the development of new diagnostic and therapeutic strategies for milk allergy.

  1. Alpha damage in non-reference waste form matrix materials

    International Nuclear Information System (INIS)

    Burnay, S.G.

    1987-05-01

    Although bitumen is the matrix material currently used for European α-bearing intermediate level waste streams, polymer and polymer-modified cement matrices could have advantages over bitumen for such wastes. Two organic matrix systems have been studied - an epoxide resin, and an epoxide modified cement. Alpha irradiations were carried out by incorporating 241 Am at approx. 0.9 Ci/l. Comparisons have been made with unirradiated material and with materials which had been γ-irradiated to the same dose as the α-irradiated samples. Measurements were made of dimensional changes, mechanical properties and the leaching behaviour of 241 Am and 137 Cs. A limited amount of swelling (< 3%) was observed in α-irradiated epoxide resin; none was observed in the epoxide modified cement. Gamma irradiation to 300 kGy has no significant effect on the mechanical properties of either system. However, alpha irradiation to the same dose produced significant changes in flexural strength, an increase for the polymer and a decrease for the polymer-cement. Leaching in these systems was found to be a diffusion-controlled process; alpha irradiation to approx. 250 kGy has little effect on the leaching behaviour of either system. (author)

  2. Alpha Shapes and Proteins

    DEFF Research Database (Denmark)

    Winter, Pawel; Sterner, Henrik; Sterner, Peter

    2009-01-01

    We provide a unified description of (weighted) alpha shapes, beta shapes and the corresponding simplicialcomplexes. We discuss their applicability to various protein-related problems. We also discuss filtrations of alpha shapes and touch upon related persistence issues.We claim that the full...... potential of alpha-shapes and related geometrical constructs in protein-related problems yet remains to be realized and verified. We suggest parallel algorithms for (weighted) alpha shapes, and we argue that future use of filtrations and kinetic variants for larger proteins will need such implementation....

  3. Alpha Momentum and Price Momentum

    Directory of Open Access Journals (Sweden)

    Hannah Lea Hühn

    2018-05-01

    Full Text Available We analyze a novel alpha momentum strategy that invests in stocks based on three-factor alphas which we estimate using daily returns. The empirical analysis for the U.S. and for Europe shows that (i past alpha has power in predicting the cross-section of stock returns; (ii alpha momentum exhibits less dynamic factor exposures than price momentum and (iii alpha momentum dominates price momentum only in the U.S. Connecting both strategies to behavioral explanations, alpha momentum is more related to an underreaction to firm-specific news while price momentum is primarily driven by price overshooting due to momentum trading.

  4. The development of an innovative, real-time monitor for airborne alpha emissions

    International Nuclear Information System (INIS)

    Gritzo, R.; Fowler, M.; Wouters, J.

    1994-01-01

    Los Alamos National Laboratory (LANL) is developing a technology for on-line, real-time monitoring of incinerator stacks for low levels of airborne alpha activity. Referred to as the Large-Volume Flow Thru Detector System (LVFTDS), this technology uses a unique design for sensitive, real-time measurements of alpha particle emissions. Scintillating plates are stacked close together so that alpha-particle emissions in the flowing gas stream strike a plate. The light pulses produced when the alpha particle strikes the plate are registered by photomultiplier tubes and processed to determine the concentration of alpha emitting radionuclides present in the air. This technology directly addresses the public's demand for fast responding, high sensitivity effluent monitoring systems. With Department of Energy (DOE) EM-50 funding LANL has fabricated a beach-top proof of concept detector system and is conducting tests to evaluate its performance. A second generation prototype is being designed, based on requirements driven by potential field test sites. An industrial partner is being solicited to license the technology. Field trials of a full-scale detector system are planned for fiscal year 1995. In this paper the LVFTDS technology is explained, including the measured performance of a prototype detector. The advantages, disadvantages, and other ramifications of applying this technology to incinerator effluent monitoring are also discussed. An overview of the development effort is also provided

  5. /sup 58,60,62/Ni (. cap alpha. ,p) three--nucleon transfer reactions and. cap alpha. optical potential ambiguities

    Energy Technology Data Exchange (ETDEWEB)

    Yuanda, Wang; Xiuming, Bao; Zhiqiang, Mao; Rongfang, Yuan; Keling, Wen; Binyin, Huang; Zhifu, Wang; Shuming, Li; Jianan, Wang; Zuxun, Sun; others, and

    1985-11-01

    The differential cross sections are measured using 26.0 MeV ..cap alpha.. particle for /sup 58,62/Ni(..cap alpha.., ..cap alpha..) /sup 58,62/Ni and /sup 58,62/Ni(..cap alpha..,p) /sup 61,65/Cu reactions as well as 25.4 MeV ..cap alpha.. particle for /sup 60/Ni(..cap alpha.., ..cap alpha..)/sup 69/Ni and /sup 60/Ni(..cap alpha.., p)/sup 63/Cu reactions. Consistent calculations with optical model and ZR DWBA are made for (..cap alpha.., ..cap alpha..) and (..cap alpha.., p) reactions by using of single, two, three and four nucleon optical potential parameters. For elastic scattering due to the ..cap alpha.. optical potential ambiguities, all the above optical potential can reproduce the experimental angular distributions. However, the single, two and three nucleon potential, including the Baird's mass systematics and the Chang's energy systematics of ..cap alpha.. potentials, obviously can not provide a reasonable fitting with the (..cap alpha..,p) reaction experimental data. Only the results from the four nucleon potential is in good agreement with the (..cap alpha..,p) reaction experimental data. This reveals that in the ..cap alpha..-particle induced transfer reactions, the real depth of the ..cap alpha..-nucleus optical potential should be rather deep.

  6. Study on molecular epidemiology of the alpha-thalassemias in Liuzhou City, Guangxi Autonomous Region, China.

    Science.gov (United States)

    Cai, Ren; Liu, Jingzhong; Wang, Lirong; Liang, Xin; Xiao, Bai; Su, Liu; Zhou, Yan; Pan, Lizhen

    2004-01-01

    Guangxi is one of the provinces of Southern China with the highest incidence of alpha-thalassemia (thal). Liuzhou is the second biggest city in Guangxi. To find out the incidence of the various alpha-thal genotypes, and their distribution in the Liuzhou area, an F820 Blood Cell Analysis System was used to measure the parameters of red blood cells. A SPIFE Rapid Auto-Electrophoresis System was used to analyze the normal and abnormal hemoglobins (Hbs). Multiplex polymerase chain reaction (mPCR) was used to detect the alpha-globin genotypes. Thirty-two (2.05%) out of 7805 young couples undergoing pre-marriage counseling, were diagnosed as having an Hb H (beta4) disease. The study of 1228 cord blood samples revealed 138 newborn children carrying an alpha-thal determinant with nine different genotypes, thus making the total incidence of alpha-thal 11.24%. Among 185 cases of Hb H, 119 (64.1%) were confirmed as being deletional, and 66 cases (35.7%) nondeletional types. The severity of the Hb H diseases could be classified in the following order: alphaCSalpha/--SEA (alphaConstant (Spring)alpha/--Southeast Asia); alpha(-4.2)/--SEA; alpha(-3.7)/--SEA. Ten cases of alpha-thal determinants were found in combination with beta-thal. The mPCR technique can detect all kinds of combinations of the three common large deletions (--SEA, alpha(-4.2) and alpha(-3.7)) accurately and conveniently.

  7. Developing linear-alpha-olefins technology. From laboratory to a commercial plant

    Energy Technology Data Exchange (ETDEWEB)

    Meiswinkel, A.; Woehl, A.; Mueller, W.; Boelt, H. [Linde AG, Pullach (Germany)

    2011-07-01

    Linear {alpha}-Olefins (LAOs) are used in several applications in chemical industry. Together with SABIC (Saudi Basic Industries Corporation) Linde jointly developed the {alpha}-SABLIN technology for a full range LAO plant as well as a 1-Hexene selective ''On Purpose'' technology (LAO OP) to cover the rapidly increasing demand for this specific comonomer. The {alpha}-SABLIN as well as the OP technology are both homogenously catalyzed systems. This is raising special challenges concerning process and reactor design compared to much more established heterogeneous systems in chemical industry. E.g., the reactor concept is a bubble-column which allows efficient mixing as well as cooling of the reaction mixture. The development of the process was based on laboratory experiments which - based on an initial conceptual design for a large scale technical process - were first transformed into a pilot device before the commercial plant was designed, engineered and successfully started up and declared as commercialized. Today the {alpha}-SABLIN technology is the only LAO technology with a commercial reference which is free for licensing. A lot of experience and knowledge from the {alpha}-SABLIN development and commercial operation was gained. Although newly developed OP technology is based on a different catalytic system, this experience is now utilized and transformed within the commercialization of this new technological development. (orig.)

  8. Targeted Alpha Therapy: From Alpha to Omega

    International Nuclear Information System (INIS)

    Allen, Barry J; Clarke, Raymond; Huang Chenyu

    2013-01-01

    This review covers the broad spectrum of Targeted Alpha Therapy (TAT) research in Australia; from in vitro and in vivo studies to clinical trials. The principle of tumour anti-vascular alpha therapy (TAVAT) is discussed in terms of its validation by Monte Carlo calculations of vascular models and the potential role of biological dosimetry is examined. Summmary of this review is as follows: 1. The essence of TAT 2. Therapeutic objectives 3. TAVAT and Monte Carlo microdosimetry 4. Biological dosimetry 5. Preclinical studies 6. Clinical trials 7. What next? 8. Obstacles. (author)

  9. Developmental expression of the alpha-skeletal actin gene

    Directory of Open Access Journals (Sweden)

    Vonk Freek J

    2008-06-01

    Full Text Available Abstract Background Actin is a cytoskeletal protein which exerts a broad range of functions in almost all eukaryotic cells. In higher vertebrates, six primary actin isoforms can be distinguished: alpha-skeletal, alpha-cardiac, alpha-smooth muscle, gamma-smooth muscle, beta-cytoplasmic and gamma-cytoplasmic isoactin. Expression of these actin isoforms during vertebrate development is highly regulated in a temporal and tissue-specific manner, but the mechanisms and the specific differences are currently not well understood. All members of the actin multigene family are highly conserved, suggesting that there is a high selective pressure on these proteins. Results We present here a model for the evolution of the genomic organization of alpha-skeletal actin and by molecular modeling, illustrate the structural differences of actin proteins of different phyla. We further describe and compare alpha-skeletal actin expression in two developmental stages of five vertebrate species (mouse, chicken, snake, salamander and fish. Our findings confirm that alpha-skeletal actin is expressed in skeletal muscle and in the heart of all five species. In addition, we identify many novel non-muscular expression domains including several in the central nervous system. Conclusion Our results show that the high sequence homology of alpha-skeletal actins is reflected by similarities of their 3 dimensional protein structures, as well as by conserved gene expression patterns during vertebrate development. Nonetheless, we find here important differences in 3D structures, in gene architectures and identify novel expression domains for this structural and functional important gene.

  10. 5alphaDH-DOC (5alpha-dihydro-deoxycorticosterone) activates androgen receptor in castration-resistant prostate cancer.

    Science.gov (United States)

    Uemura, Motohide; Honma, Seijiro; Chung, Suyoun; Takata, Ryo; Furihata, Mutsuo; Nishimura, Kazuo; Nonomura, Norio; Nasu, Yasutomo; Miki, Tsuneharu; Shuin, Taro; Fujioka, Tomoaki; Okuyama, Akihiko; Nakamura, Yusuke; Nakagawa, Hidewaki

    2010-08-01

    Prostate cancer often relapses during androgen-depletion therapy, even under the castration condition in which circulating androgens are drastically reduced. High expressions of androgen receptor (AR) and genes involved in androgen metabolism indicate a continued role for AR in castration-resistant prostate cancers (CRPCs). There is increasing evidence that some amounts of 5alpha-dihydrotestosterone (DHT) and other androgens are present sufficiently to activate AR within CRPC tissues, and enzymes involved in the androgen and steroid metabolism, such as 5alpha-steroid reductases, are activated in CRPCs. In this report, we screened eight natural 5alphaDH-steroids to search for novel products of 5alpha-steroid reductases, and identified 11-deoxycorticosterone (DOC) as a novel substrate for 5alpha-steroid reductases in CRPCs. 11-Deoxycorticosterone (DOC) and 5alpha-dihydro-deoxycorticosterone (5alphaDH-DOC) could promote prostate cancer cell proliferation through AR activation, and type 1 5alpha-steroid reductase (SRD5A1) could convert from DOC to 5alphaDH-DOC. Sensitive liquid chromatography-tandem mass spectrometric analysis detected 5alphaDH-DOC in some clinical CRPC tissues. These findings implicated that under an extremely low level of DHT, 5alphaDH-DOC and other products of 5alpha-steroid reductases within CRPC tissues might activate the AR pathway for prostate cancer cell proliferation and survival under castration.

  11. The alpha channeling effect

    Science.gov (United States)

    Fisch, N. J.

    2015-12-01

    Alpha particles born through fusion reactions in a tokamak reactor tend to slow down on electrons, but that could take up to hundreds of milliseconds. Before that happens, the energy in these alpha particles can destabilize on collisionless timescales toroidal Alfven modes and other waves, in a way deleterious to energy confinement. However, it has been speculated that this energy might be instead be channeled into useful energy, so as to heat fuel ions or to drive current. Such a channeling needs to be catalyzed by waves Waves can produce diffusion in energy of the alpha particles in a way that is strictly coupled to diffusion in space. If these diffusion paths in energy-position space point from high energy in the center to low energy on the periphery, then alpha particles will be cooled while forced to the periphery. The energy from the alpha particles is absorbed by the wave. The amplified wave can then heat ions or drive current. This process or paradigm for extracting alpha particle energy collisionlessly has been called alpha channeling. While the effect is speculative, the upside potential for economical fusion is immense. The paradigm also operates more generally in other contexts of magnetically confined plasma.

  12. Low-redshift Lyman continuum leaking galaxies with high [O III]/[O II] ratios

    Science.gov (United States)

    Izotov, Y. I.; Worseck, G.; Schaerer, D.; Guseva, N. G.; Thuan, T. X.; Fricke, K. J.; Verhamme, A.; Orlitová, I.

    2018-05-01

    We present observations with the Cosmic Origins Spectrograph onboard the Hubble Space Telescope of five star-forming galaxies at redshifts z in the range 0.2993 - 0.4317 and with high emission-line flux ratios O32 = [O III]λ5007/[O II]λ3727 ˜ 8 - 27 aiming to detect the Lyman continuum (LyC) emission. We detect LyC emission in all galaxies with the escape fractions fesc(LyC) in a range of 2 - 72 per cent. A narrow Lyα emission line with two peaks in four galaxies and with three peaks in one object is seen in medium-resolution COS spectra with a velocity separation between the peaks Vsep varying from ˜153 km s-1 to ˜ 345 km s-1. We find a general increase of the LyC escape fraction with increasing O32 and decreasing stellar mass M⋆, but with a large scatter of fesc(LyC). A tight anti-correlation is found between fesc(LyC) and Vsep making Vsep a good parameter for the indirect determination of the LyC escape fraction. We argue that one possible source driving the escape of ionizing radiation is stellar winds and radiation from hot massive stars.

  13. Central powering of the largest Lyman-α nebula is revealed by polarized radiation.

    Science.gov (United States)

    Hayes, Matthew; Scarlata, Claudia; Siana, Brian

    2011-08-17

    High-redshift Lyman-α (Lyα) blobs are extended, luminous but rare structures that seem to be associated with the highest peaks in the matter density of the Universe. Their energy output and morphology are similar to those of powerful radio galaxies, but the source of the luminosity is unclear. Some blobs are associated with ultraviolet or infrared bright galaxies, suggesting an extreme starburst event or accretion onto a central black hole. Another possibility is gas that is shock-excited by supernovae. But not all blobs are associated with galaxies, and these ones may instead be heated by gas falling into a dark-matter halo. The polarization of the Lyα emission can in principle distinguish between these options, but a previous attempt to detect this signature returned a null detection. Here we report observations of polarized Lyα from the blob LAB1 (ref. 2). Although the central region shows no measurable polarization, the polarized fraction (P) increases to ∼20 per cent at a radius of 45 kiloparsecs, forming an almost complete polarized ring. The detection of polarized radiation is inconsistent with the in situ production of Lyα photons, and we conclude that they must have been produced in the galaxies hosted within the nebula, and re-scattered by neutral hydrogen.

  14. Alpha Centauri's siren call has frustrated planet hunters

    Science.gov (United States)

    Clery, Daniel

    2018-04-01

    Alpha Centauri, a three-star system just 4 light-years away that is the sun's nearest neighbor, ought to be a great place to look for Earth-like planets. But last week, at a meeting of the European Astronomical Society here, astronomers lamented that the system has so far thwarted discovery efforts—and announced new schemes to probe it. The two sunlike stars, Alpha Centauri A and B, orbit each other closely while Proxima Centauri, a tempestuous red dwarf, hangs onto the system tenuously in a much more distant orbit. In 2016, astronomers discovered an Earth-mass planet around Proxima Centauri, but few think the planet, blasted by radiation and fierce stellar winds, is habitable. Astrobiologists believe the other two stars are more likely to host temperate, Earth-like worlds.

  15. Compensatory increase in alpha 1-globin gene expression in individuals heterozygous for the alpha-thalassemia-2 deletion.

    OpenAIRE

    Liebhaber, S A; Cash, F E; Main, D M

    1985-01-01

    alpha-Globin is encoded by the two adjacent genes, alpha 1 and alpha 2. Although it is clearly established that both alpha-globin genes are expressed, their relative contributions to alpha-globin messenger RNA (mRNA) and protein synthesis are not fully defined. Furthermore, changes that may occur in alpha-globin gene activity secondarily to the loss of function of one or more of these genes (alpha-thalassemia [Thal]) have not been directly investigated. This study further defines the expressi...

  16. Resting-State Alpha in Autism Spectrum Disorder and Alpha Associations with Thalamic Volume

    Science.gov (United States)

    Edgar, J. Christopher; Heiken, Kory; Chen, Yu-Han; Herrington, John D.; Chow, Vivian; Liu, Song; Bloy, Luke; Huang, Mingxiong; Pandey, Juhi; Cannon, Katelyn M.; Qasmieh, Saba; Levy, Susan E.; Schultz, Robert T.; Roberts, Timothy P. L.

    2015-01-01

    Alpha circuits (8-12 Hz), necessary for basic and complex brain processes, are abnormal in autism spectrum disorder (ASD). The present study obtained estimates of resting-state (RS) alpha activity in children with ASD and examined associations between alpha activity, age, and clinical symptoms. Given that the thalamus modulates cortical RS alpha…

  17. Excess alpha chains are lost from beta-thalassemic reticulocytes by proteolysis

    International Nuclear Information System (INIS)

    Testa, U.; Hinard, N.; Beuzard, Y.; Tsapis, A.; Galacteros, F.; Thomopoulos, P.; Rosa, J.

    1981-01-01

    During incubation of reticulocytes from patients with beta-thalassemia, after labeling of the hemoglobin with radioactive amino acids, the excess alpha chains are gradually lost from the cells. The aim of this study was to investigate the mechanism of this phenomenon. A system was developed in which reticulocytes from beta-thalassemia patients are labeled with [3H]leucine, washed several times in nonradioactive medium, and then incubated in the same medium containing puromycin added in order to stop further protein synthesis. The results have clearly shown that excess alpha chains are gradually degraded by proteolysis. N-ethylmaleimide or epsilon-aminocaproic acid inhibited the proteolysis of free alpha chains. The addition of either ATP or hemin did not change the rate of alpha chain degradation. The time required to degrade 50% of the pool of free alpha chains was directly dependent on the initial value of this pool. This finding suggests the absence of a significant individual variation in the ability to proteolyse free alpha chains

  18. Constraints on dark radiation from cosmological probes

    CERN Document Server

    Rossi, Graziano; Palanque-Delabrouille, Nathalie; Lesgourgues, Julien

    2015-01-01

    We present joint constraints on the number of effective neutrino species N_eff and the sum of neutrino masses M_nu, based on a technique which exploits the full information contained in the one-dimensional Lyman-Alpha forest flux power spectrum, complemented by additional cosmological probes. In particular, we obtain N_eff=2.91(+0.21)(-0.22) (95% CL) and M_nu<0.15 eV (95% CL) when we combine BOSS Lyman-Alpha forest data with CMB (Planck+ACT+SPT+WMAP polarization) measurements, and N_eff=2.88(+0.20)(-0.20) (95% CL) and M_nu<0.14 eV (95% CL) when we further add baryon acoustic oscillations. Our results provide evidence for the Cosmic Neutrino Background from N_eff~3 (N_eff=0 is rejected at more than 14 sigma), and rule out the possibility of a sterile neutrino thermalized with active neutrinos (i.e., N_eff=4) - or more generally any decoupled relativistic relic with Delta N_eff ~ 1 - at a significance of over 5 sigma, the strongest bound to date, implying that there is no need for exotic neutrino physics ...

  19. Cytokine vaccination: neutralising IL-1alpha autoantibodies induced by immunisation with homologous IL-1alpha

    DEFF Research Database (Denmark)

    Svenson, M; Hansen, M B; Thomsen, Allan Randrup

    2000-01-01

    with IL-1alpha coupled to purified protein derivative of tuberculin (PPD). Both unprimed and primed animals developed IgG aAb to IL-1alpha. These aAb persisted at high levels more than 100 days after vaccination and did not cross-react with murine IL-1beta. The induced anti-IL-1alpha aAb inhibited binding...... in mice by vaccination with recombinant murine IL-1alpha conjugated to PPD. Studies of the effects of IL-1alpha aAb in such animals may help clarify the importance of naturally occurring IL-1alpha aAb in humans and permit the evaluation of future therapies with cytokine aAb in patients...

  20. Neurofeedback training of alpha-band coherence enhances motor performance.

    Science.gov (United States)

    Mottaz, Anais; Solcà, Marco; Magnin, Cécile; Corbet, Tiffany; Schnider, Armin; Guggisberg, Adrian G

    2015-09-01

    Neurofeedback training of motor cortex activations with brain-computer interface systems can enhance recovery in stroke patients. Here we propose a new approach which trains resting-state functional connectivity associated with motor performance instead of activations related to movements. Ten healthy subjects and one stroke patient trained alpha-band coherence between their hand motor area and the rest of the brain using neurofeedback with source functional connectivity analysis and visual feedback. Seven out of ten healthy subjects were able to increase alpha-band coherence between the hand motor cortex and the rest of the brain in a single session. The patient with chronic stroke learned to enhance alpha-band coherence of his affected primary motor cortex in 7 neurofeedback sessions applied over one month. Coherence increased specifically in the targeted motor cortex and in alpha frequencies. This increase was associated with clinically meaningful and lasting improvement of motor function after stroke. These results provide proof of concept that neurofeedback training of alpha-band coherence is feasible and behaviorally useful. The study presents evidence for a role of alpha-band coherence in motor learning and may lead to new strategies for rehabilitation. Copyright © 2014 International Federation of Clinical Neurophysiology. Published by Elsevier Ireland Ltd. All rights reserved.

  1. Applications of the Long-Range Alpha Detector (LRAD) technology to low-level radioactive waste management

    International Nuclear Information System (INIS)

    Johnson, J.D.; Allander, K.S.; Bounds, J.A.; Garner, S.E.; Johnson, J.P.; MacArthur, D.W.

    1993-01-01

    Long-Range Alpha Detector (LRAD) systems are designed to monitor alpha contamination by measuring the number of ions in the air. Alpha particles are a form of ionizing radiation and a typical 5-MeV alpha particle will create about 150,000 ion pairs in air. Field tests at various DOE sites have shown that LRAD Surface Soil Monitors (SSM), Sample Monitors, and Object Monitors are faster and more sensitive than traditional alpha detectors for measuring alpha contamination. This paper discusses the various applications of LRAD technology to low-level radioactive waste management

  2. Proceedings, High-Precision $\\alpha_s$ Measurements from LHC to FCC-ee

    Energy Technology Data Exchange (ETDEWEB)

    d' Enterria, David [CERN; Skands, Peter Z. [Monash U.

    2015-01-01

    This document provides a writeup of all contributions to the workshop on "High precision measurements of $\\alpha_s$: From LHC to FCC-ee" held at CERN, Oct. 12--13, 2015. The workshop explored in depth the latest developments on the determination of the QCD coupling $\\alpha_s$ from 15 methods where high precision measurements are (or will be) available. Those include low-energy observables: (i) lattice QCD, (ii) pion decay factor, (iii) quarkonia and (iv) $\\tau$ decays, (v) soft parton-to-hadron fragmentation functions, as well as high-energy observables: (vi) global fits of parton distribution functions, (vii) hard parton-to-hadron fragmentation functions, (viii) jets in $e^\\pm$p DIS and $\\gamma$-p photoproduction, (ix) photon structure function in $\\gamma$-$\\gamma$, (x) event shapes and (xi) jet cross sections in $e^+e^-$ collisions, (xii) W boson and (xiii) Z boson decays, and (xiv) jets and (xv) top-quark cross sections in proton-(anti)proton collisions. The current status of the theoretical and experimental uncertainties associated to each extraction method, the improvements expected from LHC data in the coming years, and future perspectives achievable in $e^+e^-$ collisions at the Future Circular Collider (FCC-ee) with $\\cal{O}$(1--100 ab$^{-1}$) integrated luminosities yielding 10$^{12}$ Z bosons and jets, and 10$^{8}$ W bosons and $\\tau$ leptons, are thoroughly reviewed. The current uncertainty of the (preliminary) 2015 strong coupling world-average value, $\\alpha_s(m_Z)$ = 0.1177 $\\pm$ 0.0013, is about 1\\%. Some participants believed this may be reduced by a factor of three in the near future by including novel high-precision observables, although this opinion was not universally shared. At the FCC-ee facility, a factor of ten reduction in the $\\alpha_s$ uncertainty should be possible, mostly thanks to the huge Z and W data samples available.

  3. Strategy for Realizing High-Precision VUV Spectro-Polarimeter

    Science.gov (United States)

    Ishikawa, R.; Narukage, N.; Kubo, M.; Ishikawa, S.; Kano, R.; Tsuneta, S.

    2014-12-01

    Spectro-polarimetric observations in the vacuum ultraviolet (VUV) range are currently the only means to measure magnetic fields in the upper chromosphere and transition region of the solar atmosphere. The Chromospheric Lyman-Alpha Spectro-Polarimeter (CLASP) aims to measure linear polarization at the hydrogen Lyman- α line (121.6 nm). This measurement requires a polarization sensitivity better than 0.1 %, which is unprecedented in the VUV range. We here present a strategy with which to realize such high-precision spectro-polarimetry. This involves the optimization of instrument design, testing of optical components, extensive analyses of polarization errors, polarization calibration of the instrument, and calibration with onboard data. We expect that this strategy will aid the development of other advanced high-precision polarimeters in the UV as well as in other wavelength ranges.

  4. Determination of alpha-naphthol by an oscillating chemical reaction using the analyte pulse perturbation technique

    International Nuclear Information System (INIS)

    Yang Wu; Sun Kanjun; Lv Weilian; Bo Lili; He Xiaoyan; Suo Nan; Gao Jinzhang

    2005-01-01

    An analytical method for the determination of alpha-naphthol (α-NP) is proposed by the sequential perturbation caused by different amounts of alpha-naphthol on the oscillating chemical system involving the Cu(II)-catalyzed oscillating reaction between hydrogen peroxide and sodium thiocyanate in an alkaline medium with the aid of continuous-flow stirred tank reactor (CSTR). The method relies on the linear relationship between the changes in the oscillation amplitude of the chemical system and the concentration of alpha-naphthol. The use of the analyte pulse perturbation technique permits sequential determinations in the same oscillating system owing to the expeditiousness with which the steady state is regained after each perturbation. The calibration curve obeys a linear equation very well when the concentration of alpha-naphthol is over the range 0.034-530 umol/L (r = 0.9991). Influences of temperature, injection points, flow rate and reaction variables on the oscillating system are investigated in detail and the possible mechanism of action of alpha-naphthol to the chemical oscillating system is also discussed. The method has been successfully used for the determination of α-naphthol in carbaryl hydrolysates

  5. Alpha detection in pipes using an inverting membrane scintillator

    Energy Technology Data Exchange (ETDEWEB)

    Kendrick, D.T.; Cremer, C.D.; Lowry, W. [Science and Engineering Associates, Inc., Albuquerque, NM (United States)] [and others

    1995-10-01

    Characterization of surface alpha emitting contamination inside enclosed spaces such as piping systems presents an interesting radiological measurement challenge. Detection of these alpha particles from the exterior of the pipe is impossible since the alpha particles are completely absorbed by the pipe wall. Traditional survey techniques, using hand-held instruments, simply can not be used effectively inside pipes. Science and Engineering Associates, Inc. is currently developing an enhancement to its Pipe Explorer{trademark} system that will address this challenge. The Pipe Explorer{trademark} uses a unique sensor deployment method where an inverted tubular membrane is propagated through complex pipe runs via air pressure. The inversion process causes the membrane to fold out against the pipe wall, such that no part of the membrane drags along the pipe wall. This deployment methodology has been successfully demonstrated at several DOE sites to transport specially designed beta and gamma, scintillation detectors into pipes ranging in length up to 250 ft.

  6. Workshop on Precision Measurements of $\\alpha_s$

    Energy Technology Data Exchange (ETDEWEB)

    Bethke, Siegfried; /Munich, Max Planck Inst.; Hoang, Andre H.; /Vienna U.; Kluth, Stefan; /Munich, Max Planck Inst.; Schieck, Jochen; /Munich U.; Stewart, Iain W.; Aoki, S.; Beneke, M.; Bethke, S.; Blumlein, J.; Brambilla, N.; Brodsky, S.; /MIT, LNS

    2011-10-01

    These are the proceedings of the Workshop on Precision Measurements of {alpha}{sub s} held at the Max-Planck-Institute for Physics, Munich, February 9-11, 2011. The workshop explored in depth the determination of {alpha}{sub s}(m{sub Z}) in the {ovr MS} scheme from the key categories where high precision measurements are currently being made, including DIS and global PDF fits, {tau}-decays, electro-weak precision observables and Z-decays, event-shapes, and lattice QCD. These proceedings contain a short summary contribution from the speakers, as well as the lists of authors, conveners, participants, and talks.

  7. p25alpha relocalizes in oligodendroglia from myelin to cytoplasmic inclusions in multiple system atrophy

    DEFF Research Database (Denmark)

    Song, Yun Ju C; Lundvig, Ditte M S; Huang, Yue

    2007-01-01

    cytoplasmic inclusions. Overall, the data indicate that changes in the cellular interactions between MBP and p25alpha occur early in MSA and contribute to abnormalities in myelin and subsequent alpha-synuclein aggregation and the ensuing neuronal degeneration that characterizes this disease....

  8. Performance comparison of scintillators for alpha particle detectors

    Energy Technology Data Exchange (ETDEWEB)

    Morishita, Yuki [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Yamamoto, Seiichi [Graduate School of Medicine, Nagoya University, 1-1-20 Daiko-Minami, Higashi-ku, Nagoya, Aichi 461-8673 (Japan); Izaki, Kenji [Japan Atomic Energy Agency, Muramatsu 4-33, Tokai-mura, Ibaraki 319-1194 (Japan); Kaneko, Junichi H.; Toui, Kohei; Tsubota, Youichi; Higuchi, Mikio [Graduate School of Engineering, Hokkaido University, Kita 13, Nishi 8, Kita-ku, Sapporo, Hokkaido 060-8628 (Japan)

    2014-11-11

    Scintillation detectors for alpha particles are often used in nuclear fuel facilities. Alpha particle detectors have also become important in the research field of radionuclide therapy using alpha emitters. ZnS(Ag) is the most often used scintillator for alpha particle detectors because its light output is high. However, the energy resolution of ZnS(Ag)-based scintillation detectors is poor because they are not transparent. A new ceramic sample, namely the cerium doped Gd{sub 2}Si{sub 2}O{sub 7} (GPS) scintillator, has been tested as alpha particle detector and its performances have been compared to that one of three different scintillating materials: ZnS(Ag), GAGG and a standard plastic scintillator. The different scintillating materials have been coupled to two different photodetectors, namely a photomultiplier tube (PMT) and a Silicon Photo-multiplier (Si-PM): the performances of each detection system have been compared. Promising results as far as the energy resolution performances (10% with PMT and 14% with Si-PM) have been obtained in the case of GPS and GAGG samples. Considering the quantum efficiencies of the photodetectors under test and their relation to the emission wavelength of the different scintillators, the best results were achieved coupling the GPS with the PMT and the GAGG with the Si-PM.

  9. The escape of Lyman photons from a young starburst: the case of Haro11†

    Science.gov (United States)

    Hayes, Matthew; Östlin, Göran; Atek, Hakim; Kunth, Daniel; Mas-Hesse, J. Miguel; Leitherer, Claus; Jiménez-Bailón, Elena; Adamo, Angela

    2007-12-01

    Lyman α (Lyα) is one of the dominant tools used to probe the star-forming galaxy population at high redshift (z). However, astrophysical interpretations of data drawn from Lyα alone hinge on the Lyα escape fraction which, due to the complex radiative transport, may vary greatly. Here, we map the Lyα emission from the local luminous blue compact galaxy Haro11, a known emitter of Lyα and the only known candidate for low-z Lyman continuum emission. To aid in the interpretation, we perform a detailed ultraviolet and optical multiwavelength analysis and model the stellar population, dust distribution, ionizing photon budget, and star-cluster population. We use archival X-ray observations to further constrain properties of the starburst and estimate the neutral hydrogen column density. The Lyα morphology is found to be largely symmetric around a single young star-forming knot and is strongly decoupled from other wavelengths. From general surface photometry, only very slight correlation is found between Lyα and Hα, E(B - V), and the age of the stellar population. Only around the central Lyα bright cluster do we find the Lyα/Hα ratio at values predicted by the recombination theory. The total Lyα escape fraction is found to be just 3 per cent. We compute that ~90 per cent of the Lyα photons that escape do so after undergoing multiple resonance scattering events, masking their point of origin. This leads to a largely symmetric distribution and, by increasing the distance that photons must travel to escape, decreases the escape probability significantly. While dust must ultimately be responsible for the destruction of Lyα, it plays a little role in governing the observed morphology, which is regulated more by interstellar medium kinematics and geometry. We find tentative evidence for local Lyα equivalent width in the immediate vicinity of star clusters being a function of cluster age, consistent with hydrodynamic studies. We estimate the intrinsic production

  10. GABA regulates the rat hypothalamic-pituitary-adrenocortical axis via different GABA-A receptor alpha-subtypes

    DEFF Research Database (Denmark)

    Mikkelsen, Jens D; Bundzikova, Jana; Larsen, Marianne Hald

    2008-01-01

    dependent on the composition of the GABA-A receptor subunits through which they act. We show here that positive modulators of alpha(1)-subtype containing GABA-A receptors with zolpidem (10 mg/kg) increase HPA activity in terms of increase in plasma corticosterone and induction of Fos in the PVN, whereas...... after positive modulation of GABA-A receptors composed of alpha(1)-subunit(s) affects a selective afferent system than the PVN, which is distinct from another afferent system(s) activated by non alpha(1)-containing GABA-A receptors....

  11. Alpha particles spectrometer with photodiode PIN; Espectrometro de particulas alfa con fotodiodo PIN

    Energy Technology Data Exchange (ETDEWEB)

    Chacon R, A.; Hernandez V, R.; Hernandez D, V. M.; Vega C, H. R. [Universidad Autonoma de Zacatecas, Unidades Academicas de Estudios Nucleares e Ingenieria Electrica, Calle Cipres No. 10, Fracc. La Penuela, 09869 Zacatecas (Mexico); Ramirez G, J. [Instituto Nacional de Estadistica Geografia e Informatica, Direccion General de Innovacion y Tecnologia de Informacion, Av. Heroes de Nacozari Sur 2301, Fracc. Jardines del Parque, 20276 Aguascalientes (Mexico)], e-mail: achruiz@hotmail.com

    2009-10-15

    The radiation propagates in form of electromagnetic waves or corpuscular radiation; if the radiation energy causes ionization in environment that crosses it is considered ionizing radiation. To detect radiation several detectors types are used, if the radiation are alpha particles are used detectors proportional type or trace elements. In this work the design results, construction and tests of an alpha particles spectrometer are presented, which was designed starting from a photodiode PIN type. The system design was simulated with a code for electronic circuits. With results of simulation phase was constructed the electronic phase that is coupled to a multichannel analyzer. The resulting electronic is evaluated analyzing the electronic circuit performance before an alphas triple source and alpha radiation that produce two smoke detectors of domestic use. On the tests phase we find that the system allows obtain, in a multichannel, the pulses height spectrum, with which we calibrate the system. (Author)

  12. 13 native human interferon-alpha species assessed for immunoregulatory properties

    DEFF Research Database (Denmark)

    Heron, I; Hokland, M; Berg, K

    1983-01-01

    Human leukocytes treated with Sendai virus yield interferon predominantly of the alpha-type (HuIFN-alpha). Successful attempts to purify these "native" species have been performed and the final analysis, which included an SDS-PAGE disclosed 13 stained and separated IFN-proteins in the molecular...... by IFN titration on human cells, the "immunological efficacies" of the 13 different HuIFN-alpha species were determined in three different immunological systems with the following results: (1) Augmentation of the NK function was a property of all species, although the two lower species (16.6 kD, 16.9 k...

  13. Combining Alphas via Bounded Regression

    Directory of Open Access Journals (Sweden)

    Zura Kakushadze

    2015-11-01

    Full Text Available We give an explicit algorithm and source code for combining alpha streams via bounded regression. In practical applications, typically, there is insufficient history to compute a sample covariance matrix (SCM for a large number of alphas. To compute alpha allocation weights, one then resorts to (weighted regression over SCM principal components. Regression often produces alpha weights with insufficient diversification and/or skewed distribution against, e.g., turnover. This can be rectified by imposing bounds on alpha weights within the regression procedure. Bounded regression can also be applied to stock and other asset portfolio construction. We discuss illustrative examples.

  14. Genetics Home Reference: alpha thalassemia

    Science.gov (United States)

    ... Facebook Twitter Home Health Conditions Alpha thalassemia Alpha thalassemia Printable PDF Open All Close All Enable Javascript to view the expand/collapse boxes. Description Alpha thalassemia is a blood disorder that reduces the production ...

  15. Coaching the alpha male.

    Science.gov (United States)

    Ludeman, Kate; Erlandson, Eddie

    2004-05-01

    Highly intelligent, confident, and successful, alpha males represent about 70% of all senior executives. Natural leaders, they willingly take on levels of responsibility most rational people would find overwhelming. But many of their quintessential strengths can also make alphas difficult to work with. Their self-confidence can appear domineering. Their high expectations can make them excessively critical. Their unemotional style can keep them from inspiring their teams. That's why alphas need coaching to broaden their interpersonal tool kits while preserving their strengths. Drawing from their experience coaching more than 1,000 senior executives, the authors outline an approach tailored specifically for the alpha. Coaches get the alpha's attention by inundating him with data from 360-degree feedback presented in ways he will find compelling--both hard-boiled metrics and vivid verbatim comments from colleagues about his strengths and weaknesses. A 360-degree assessment is a wake-up call for most alphas, providing undeniable proof that their behavior doesn't work nearly as well as they think it does. That paves the way for a genuine commitment to change. In order to change, the alpha must venture into unfamiliar--and often uncomfortable--psychological territory. He must admit vulnerability, accept accountability not just for his own work for others', connect with his underlying emotions, learn to motivate through a balance of criticism and validation, and become aware of unproductive behavior patterns. The goal of executive coaching is not simply to treat the alpha as an individual problem but to improve the entire team dynamic. Initial success creates an incentive to persevere, and the virtuous cycle reverberates throughout the entire organization.

  16. Taraxacum officinale induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells.

    Science.gov (United States)

    Koo, Hyun-Na; Hong, Seung-Heon; Song, Bong-Keun; Kim, Cheorl-Ho; Yoo, Young-Hyun; Kim, Hyung-Min

    2004-01-16

    Taraxacum officinale (TO) has been frequently used as a remedy for women's disease (e.g. breast and uterus cancer) and disorders of the liver and gallbladder. Several earlier studies have indicated that TO exhibits anti-tumor properties, but its mechanism remains to be elucidated. In this study, we investigated the effect of TO on the cytotoxicity and production of cytokines in human hepatoma cell line, Hep G2. Our results show that TO decreased the cell viability by 26%, and significantly increased the tumor necrosis factor (TNF)-alpha and interleukin (IL)-1alpha production compared with media control (about 1.6-fold for TNF-alpha, and 2.4-fold for IL-1alpha, P < 0.05). Also, TO strongly induced apoptosis of Hep G2 cells as determined by flow cytometry. Increased amounts of TNF-alpha and IL-1alpha contributed to TO-induced apoptosis. Anti-TNF-alpha and IL-1alpha antibodies almost abolished it. These results suggest that TO induces cytotoxicity through TNF-alpha and IL-1alpha secretion in Hep G2 cells.

  17. Experimentation Using the Mir Station as a Space Laboratory

    Science.gov (United States)

    1998-01-01

    Institute for Machine Building (TsNIIMASH) Korolev, Moscow Region, Russia V. Teslenko and N. Shvets Energia Space Corporation Korolev, Moscow...N. Shvets Energia Space Corporation Korolev, Moscow Region, Russia J. A. Drakes/ D. G. Swann, and W. K. McGregor* Sverdrup Technology, Inc...and plume computations. Excitation of the plume gas molecular electronic states by solar radiation, geo- corona Lyman-alpha, and electronic impact

  18. Nuclear Track Detector Characterization via Alpha-Spectrometry for Radioprotection Use

    Energy Technology Data Exchange (ETDEWEB)

    Morelli, D.; Imme, G.; Catalano, R. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, via S. Sofia, 64- 95123 Catania (Italy); Istituto Nazionale di Fisica Nucleare - Sezione di Catania, via S. Sofia, 64- 95123 Catania (Italy); Aranzulla, M. [Istituto Nazionale Geofisica e Vulcanologia - Sezione di Catania, piazza Roma, 2- 95127 Catania (Italy); Tazzer, A. L. Rosselli; Mangano, G. [Dipartimento di Fisica e Astronomia, Universita degli Studi di Catania, via S. Sofia, 64- 95123 Catania (Italy)

    2011-12-13

    Solid Nuclear Track Detectors (SNTDs), CR-39 type, are usually adopted to monitor radon gas concentrations. In order to characterize the detectors according to track geometrical parameters, detectors were irradiated inside a vacuum chamber by alpha particles at twelve energy values, obtained by different Mylar foils in front of a {sup 241}Am source. The alpha energy values were verified using a Si detector. After the exposure to the alpha particles, the detectors were chemically etched to enlarge the tracks, which were then analyzed by means of a semiautomatic system composed of an optical microscope equipped with a CCD camera connected to a personal computer to store images. A suitable routine analyzed the track parameters: major and minor axis length and mean grey level, allowing us to differentiate tracks according to the incident alpha energy and then to individuate the discrimination factors for radon alpha tracks. The combined use of geometrical and optical parameters allows one to overcome the ambiguity in the alpha energy determination due to the non-monotonicity of each parameter versus energy. After track parameter determination, a calibration procedure was performed by means of a radon chamber. The calibration was verified through an inter-comparing survey.

  19. In-flight performance of the polarization modulator in the CLASP rocket experiment

    Science.gov (United States)

    Ishikawa, Shin-nosuke; Shimizu, Toshifumi; Kano, Ryohei; Bando, Takamasa; Ishikawa, Ryoko; Giono, Gabriel; Beabout, Dyana L.; Beabout, Brent L.; Nakayama, Satoshi; Tajima, Takao

    2016-07-01

    We developed a polarization modulation unit (PMU), a motor system to rotate a waveplate continuously. In polarization measurements, the continuous rotating waveplate is an important element as well as a polarization analyzer to record the incident polarization in a time series of camera exposures. The control logic of PMU was originally developed for the next Japanese solar observation satellite SOLAR-C by the SOLAR-C working group. We applied this PMU for the Chromospheric Lyman-alpha SpectroPolarimeter (CLASP). CLASP is a sounding rocket experiment to observe the linear polarization of the Lyman-alpha emission (121.6 nm vacuum ultraviolet) from the upper chromosphere and transition region of the Sun with a high polarization sensitivity of 0.1 % for the first time and investigate their vector magnetic field by the Hanle effect. The driver circuit was developed to optimize the rotation for the CLASP waveplate (12.5 rotations per minute). Rotation non- uniformity of the waveplate causes error in the polarization degree (i.e. scale error) and crosstalk between Stokes components. We confirmed that PMU has superior rotation uniformity in the ground test and the scale error and crosstalk of Stokes Q and U are less than 0.01 %. After PMU was attached to the CLASP instrument, we performed vibration tests and confirmed all PMU functions performance including rotation uniformity did not change. CLASP was successfully launched on September 3, 2015, and PMU functioned well as designed. PMU achieved a good rotation uniformity, and the high precision polarization measurement of CLASP was successfully achieved.

  20. Immunodetection of Thyroid Hormone Receptor (Alpha1/Alpha2) in the Rat Uterus and Oviduct

    International Nuclear Information System (INIS)

    Öner, Jale; Öner, Hakan

    2007-01-01

    The aim of this study was to investigate the immunolocalization and the existence of thyroid hormone receptors (THR) (alpha1/alpha2) in rat uterus and oviduct. For this purpose 6 female Wistar albino rats found in estrous period were used. Tissue samples fixed in 10% neutral formalin were examined immunohistochemically. Sections were incubated with primary mouse-monoclonal THR (alpha1/alpha2) antibody. In uterus, THR (alpha1/alpha2) immunoreacted strongly with uterine luminal epithelium, endometrial gland epithelium and endometrial stromal cells and, moderately with myometrial smooth muscle. In oviduct, they were observed moderately in the epithelium of the tube and the smooth muscle cells of the muscular layer. In conclusion, the presence of THR in uterus and oviduct suggests that these organs are an active site of thyroid hormones

  1. Alpha particle emitters in medicine

    International Nuclear Information System (INIS)

    Fisher, D.R.

    1989-09-01

    Radiation-induced cancer of bone, liver and lung has been a prominent harmful side-effect of medical applications of alpha emitters. In recent years, however, the potential use of antibodies labeled with alpha emitting radionuclides against cancer has seemed promising because alpha particles are highly effective in cell killing. High dose rates at high LET, effectiveness under hypoxic conditions, and minimal expectancy of repair are additional advantages of alpha emitters over antibodies labeled with beta emitting radionuclides for cancer therapy. Cyclotron-produced astatine-211 ( 211 At) and natural bismuth-212 ( 212 Bi) have been proposed and are under extensive study in the United States and Europe. Radium-223 ( 223 Ra) also has favorable properties as a potential alpha emitting label, including a short-lived daughter chain with four alpha emissions. The radiation dosimetry of internal alpha emitters is complex due to nonuniformly distributed sources, short particle tracks, and high relative specific ionization. The variations in dose at the cellular level may be extreme. Alpha-particle radiation dosimetry, therefore, must involve analysis of statistical energy deposition probabilities for cellular level targets. It must also account fully for nonuniform distributions of sources in tissues, source-target geometries, and particle-track physics. 18 refs., 4 figs

  2. Alpha-synuclein gene deletion decreases brain palmitate uptake and alters the palmitate metabolism in the absence of alpha-synuclein palmitate binding

    DEFF Research Database (Denmark)

    Golovko, Mikhail Y; Færgeman, Nils J.; Cole, Nelson B

    2005-01-01

    Alpha-synuclein is an abundant protein in the central nervous system that is associated with a number of neurodegenerative disorders, including Parkinson's disease. Its physiological function is poorly understood, although recently it was proposed to function as a fatty acid binding protein. To b......, alpha-synuclein has effects on 16:0 uptake and metabolism similar to those of an FABP, but unlike FABP, it does not directly bind 16:0; hence, the mechanism underlying these effects is different from that of a classical FABP....

  3. Stabilization of {alpha}-amylase by using anionic surfactant during the immobilization process

    Energy Technology Data Exchange (ETDEWEB)

    El-Batal, A.I. [National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt); Atia, K.S. [Nuclear Research Center, Radioisotopes Applications Division, Abo-Zable, P.O. Box 13759, Cairo (Egypt)]. E-mail: ks_atia@yahoo.com; Eid, M. [National Center for Radiation Research and Technology, P.O. Box 29, Nasr City, Cairo (Egypt)

    2005-10-01

    This work describes the entrapment of {alpha}-amylase into butylacrylate-acrylic acid copolymer (BuA/AAc) using {gamma} irradiation. The effect of an anionic surfactant (AOT), the reuse efficiency, and kinetic behavior of immobilized {alpha}-amylase were studied. Covering of {alpha}-amylase with bis-(2-ethylhexyl)sulfosuccinate sodium salt (AOT) made the enzyme more stable than the uncovered form. The hydrolytic activity of the pre-coated immobilized {alpha}-amylase was increased below the critical micelle concentration (cmc) (10mmol/L). The results showed an increase in the relative activity with increase in the degree of hydration. The pre-coated immobilized {alpha}-amylase showed a higher k{sub cat}/K{sub m} and lower activation energy compared to the free and uncoated-immobilized preparation, respectively. The results suggest that the immobilization of {alpha}-amylase is a potentially useful approach for commercial starch hydrolysis in two-phase systems.

  4. Synergetic fMRI-EEG brain mapping in alpha-rhythm voluntary control mode.

    Science.gov (United States)

    Shtark, M B; Verevkin, E G; Kozlova, L I; Mazhirina, K G; Pokrovskii, M A; Petrovskii, E D; Savelov, A A; Starostin, A S; Yarosh, S V

    2015-03-01

    For the first time in neurobiology-related issues, the synergistic spatial dynamics of EEG and fMRI (BOLD phenomenon) was studied during cognitive alpha biofeedback training in the operant conditioning mode (acoustic reinforcement of alpha-rhythm development and stability). Significant changes in alpha-rhythm intensity were found in T6 electrode area (Brodmann area 37). Brodmann areas related to solving alpha-training tasks and maximally involved in the formation of new neuronal network were middle and superior temporal gyri (areas 21, 22, and 37), fusiform gyrus, inferior frontal gyrus (areas 4, 6, and 46), anterior cingulate gyrus (areas 23 and 24), cuneus, and precuneus (area 7). Wide involvement of Brodmann areas is determined by psychological architecture of alpha-rhythm generating system control that includes complex cognitive activities: decision making, retrieval of long-term memory, evaluation of the reward and control efficiency during alpha-EEG biofeedback.

  5. A practical relation between atomic numbers and alpha coefficients

    International Nuclear Information System (INIS)

    Lachance, G.R.

    1980-01-01

    A first approximation indicates that fundamental alpha coefficients for a given analyte vary as a function of the ratio of their respective atomic number raised to a power. This simple rule applies mainly at the limits (i.e., when the weight fraction of analyte i, Wsub(i) is of the order of 0.0 or 1.0) in cases of absorption and weak enhancement. The relation thus provides a means of generating coefficients for the system i-k from experimental data obtained on system i-j and a means of verifying experimental alphas, since arrays of coefficients must show a high degree of concordance. (author)

  6. Aqueous suspensions of {alpha}Al{sub 2}O{sub 3}/SiC mixed systems

    Energy Technology Data Exchange (ETDEWEB)

    Pagnoux, C.; Baklouti, S.; Chartier, T.; Baumard, J.F. [ENSCI, Limoges (France). LMCTS

    1997-12-31

    The preparation of aqueous {alpha}-Al{sub 2}O{sub 3}, {alpha}-SiO{sub 2} and {alpha}-SiC suspensions with polyelectrolytes, respectively the NH{sub 4}{sup +} salt of polymethacrylic acid (PMA-NH{sub 4}{sup +}) and acidic form polyethylene imine (PEI-H{sup +}) is investigated. It is based on the adsorption of these polyelectrolytes which in turn depends mainly on the nature of the polyelectrolyte, and the charge density which develops on the powder surface in water. Good dispersion and stability of dispersions are then obtained through electrostatic and steric stabilization. As an application, the preparation of an Al{sub 2}O{sub 3}-SiC aqueous mixed slurry was investigated as a preliminary step for processing of Al{sub 2}O{sub 3}/SiC nanocomposites. (orig.) 2 refs.

  7. Antihydrogen detection in ALPHA

    Energy Technology Data Exchange (ETDEWEB)

    Hydomako, Richard, E-mail: rhydomako@phas.ucalgary.ca [University of Calgary, Department of Physics and Astronomy (Canada); Bruun Andresen, Gorm [Aarhus University, Department of Physics and Astronomy (Denmark); Ashkezari, Mohammad Dehghani [Simon Fraser University, Department of Physics (Canada); Baquero-Ruiz, Marcelo [University of California, Department of Physics (United States); Bertsche, William [Swansea University, Department of Physics (United Kingdom); Butler, Eoin [CERN, European Laboratory for Particle Physics (Switzerland); Bowe, Paul David [Aarhus University, Department of Physics and Astronomy (Denmark); Cesar, Claudo Lenz [Universidade Federal do Rio de Janeiro, Instituto de Fsica (Brazil); Chapman, Steve [University of California, Department of Physics (United States); Charlton, Michael [Swansea University, Department of Physics (United Kingdom); Fajans, Joel [University of California, Department of Physics (United States); Friesen, Tim; Fujiwara, Makoto C. [University of Calgary, Department of Physics and Astronomy (Canada); Gill, David Russell [TRIUMF (Canada); Hangst, Jeffrey Scott [Aarhus University, Department of Physics and Astronomy (Denmark); Hardy, Walter Newbold [University of British Columbia, Department of Physics and Astronomy (Canada); Hayano, Ryugo S. [University of Tokyo, Department of Physics (Japan); Hayden, Michael Edward [Simon Fraser University, Department of Physics (Canada); Humphries, Andrew James [Swansea University, Department of Physics (United Kingdom); Jonsell, Svante [Stockholm University, Fysikum (Sweden); Collaboration: ALPHA Collaboration; and others

    2012-12-15

    The ALPHA project is an international collaboration, based at CERN, with the experimental goal of performing precision spectroscopic measurements on antihydrogen. As part of this endeavor, the ALPHA experiment includes a silicon tracking detector. This detector consists of a three-layer array of silicon modules surrounding the antihydrogen trapping region of the ALPHA apparatus. Using this device, the antihydrogen annihilation position can be determined with a spatial resolution of better than 5 mm. Knowledge of the annihilation distribution was a critical component in the recently successful antihydrogen trapping effort. This paper will describe the methods used to reconstruct annihilation events in the ALPHA detector. Particular attention will be given to the description of the background rejection criteria.

  8. Long-range alpha detection applied to soil surface monitoring

    International Nuclear Information System (INIS)

    Caress, R.W.; Allander, K.S.; Bounds, J.A.; Catlett, M.M.; MacArthur, D.W.; Rutherford, D.A.

    1992-01-01

    The long-range alpha detection (LRAD) technique depends on the detection of ion pairs generated by alpha particles losing energy in air rather than on detection of the alpha particles themselves. Typical alpha particles generated by uranium will travel less than 3 cm in air. In contrast, the ions have been successfully detected many inches or feet away from the contamination. Since LRAD detection systems are sensitive to all ions simultaneously, large LRAD soil surface monitors (SSMS) can be used to collect all of the ions from a large sample. The LRAD SSMs are designed around the fan-less LRAD detector. In this case a five-sided box with an open bottom is placed on the soil surface. Ions generated by alpha decays on the soil surface are collected on a charged copper plate within the box. These ions create a small current from the plate to ground which is monitored with a sensitive electrometer. The current measured is proportional to the number of ions in the box, which is, in turn, proportional to the amount of alpha contamination on the surface of the soil. This report includes the design and construction of a 1-m by 1-m SSM as well as the results of a study at Fernald, OH, as part of the Uranium in Soils Integrated Demonstration

  9. Buffett’s Alpha

    DEFF Research Database (Denmark)

    Frazzini, Andrea; Kabiller, David; Heje Pedersen, Lasse

    Berkshire Hathaway has realized a Sharpe ratio of 0.76, higher than any other stock or mutual fund with a history of more than 30 years, and Berkshire has a significant alpha to traditional risk factors. However, we find that the alpha becomes insignificant when controlling for exposures to Betting...

  10. Alpha1 and Alpha2 Integrins Mediate Invasive Activity of Mouse Mammary Carcinoma Cells through Regulation of Stromelysin-1 Expression

    Energy Technology Data Exchange (ETDEWEB)

    Lochter, Andre; Navre, Marc; Werb, Zena; Bissell, Mina J

    1998-06-29

    Tumor cell invasion relies on cell migration and extracellular matrix proteolysis. We investigated the contribution of different integrins to the invasive activity of mouse mammary carcinoma cells. Antibodies against integrin subunits {alpha}6 and {beta}1, but not against {alpha}1 and {alpha}2, inhibited cell locomotion on a reconstituted basement membrane in two-dimensional cell migration assays, whereas antibodies against {beta}1, but not against a6 or {alpha}2, interfered with cell adhesion to basement membrane constituents. Blocking antibodies against {alpha}1 integrins impaired only cell adhesion to type IV collagen. Antibodies against {alpha}1, {alpha}2, {alpha}6, and {beta}1, but not {alpha}5, integrin subunits reduced invasion of a reconstituted basement membrane. Integrins {alpha}1 and {alpha}2, which contributed only marginally to motility and adhesion, regulated proteinase production. Antibodies against {alpha}1 and {alpha}2, but not {alpha}6 and {beta}1, integrin subunits inhibited both transcription and protein expression of the matrix metalloproteinase stromelysin-1. Inhibition of tumor cell invasion by antibodies against {alpha}1 and {alpha}2 was reversed by addition of recombinant stromelysin-1. In contrast, stromelysin-1 could not rescue invasion inhibited by anti-{alpha}6 antibodies. Our data indicate that {alpha}1 and {alpha}2 integrins confer invasive behavior by regulating stromelysin-1 expression, whereas {alpha}6 integrins regulate cell motility. These results provide new insights into the specific functions of integrins during tumor cell invasion.

  11. Infliximab TNF-alpha antagonist decreases intraabdominal adhesions

    International Nuclear Information System (INIS)

    Kurukahvecioglu, O.; Koksal, H.; Yazicioglu, O.; Kerem, M.; Taneri, F.; Gulbahar, O.; Erdem, O.; Engin, D.

    2007-01-01

    Objective was to evaluate the effect of infliximab on adhesion formation and its associated morbidity and complications. This study was performed in the Faculty of Medicine, Gaze University, Turkey between July 2005 and October 2005. Thirty-five rats were randomly divided into 4 groups. Laparotomy was performed in the Sham group (n=5), whereas cecal abrasion was carried out in all other groups. After cecal abrasion 0.9% sodium chloride was administered in the saline group (n=10), infliximab was administered to the study group (n=10) and nothing was administered to the last group (n=10). Adhesion formation was evaluated with macroscopic adhesion scoring systems. Peritoneal fluid samples and mesenteric lymph node biopsies were taken to rule out bacterial peritonitis. Blood and peritoneal irrigation fluids samples were taken to measure the Tumor necrosis factor-alpha (TNF-alpha) levels. Macroscopic adhesion scores showed fewer adhesions in the infliximab group. The infliximab group had significantly fewer adhesions than the abrasion control and saline groups. According to the histological findings, there were no statistically significant differences between the groups. Early blocking of the activity of TNF-alpha after cecal abrasion resulted in lower rates of adhesion formation, macroscopically. The TNF-alpha, a proinflammatory cytokine appears to be an important mediator for postoperative adhesion formation. (author)

  12. Determination of $\\alpha_{s}$ using Jet Rates at LEP with the OPAL detector

    CERN Document Server

    Abbiendi, G.; Akesson, P.F.; Alexander, G.; Anagnostou, G.; Anderson, K.J.; Asai, S.; Axen, D.; Bailey, I.; Barberio, E.; Barillari, T.; Barlow, R.J.; Batley, R.J.; Bechtle, P.; Behnke, T.; Bell, Kenneth Watson; Bell, P.J.; Bella, G.; Bellerive, A.; Benelli, G.; Bethke, S.; Biebel, O.; Boeriu, O.; Bock, P.; Boutemeur, M.; Braibant, S.; Brown, Robert M.; Burckhart, H.J.; Campana, S.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, D.G.; Ciocca, C.; Csilling, A.; Cuffiani, M.; Dado, S.; De Roeck, A.; De Wolf, E.A.; Desch, K.; Dienes, B.; Donkers, M.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Etzion, E.; Fabbri, F.; Ferrari, P.; Fiedler, F.; Fleck, I.; Ford, M.; Frey, A.; Gagnon, P.; Gary, John William; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Giunta, Marina; Goldberg, J.; Gross, E.; Grunhaus, J.; Gruwe, M.; Gunther, P.O.; Gupta, A.; Hajdu, C.; Hamann, M.; Hanson, G.G.; Harel, A.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herten, G.; Heuer, R.D.; Hill, J.C.; Horvath, D.; Igo-Kemenes, P.; Ishii, K.; Jeremie, H.; Jovanovic, P.; Junk, T.R.; Kanzaki, J.; Karlen, D.; Kawagoe, K.; Kawamoto, T.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kluth, S.; Kobayashi, T.; Kobel, M.; Komamiya, S.; Kramer, T.; Krasznahorkay, A.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kupper, M.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lellouch, D.; Lettso, J.; Levinson, L.; Lillich, J.; Lloyd, S.L.; Loebinger, F.K.; Lu, J.; Ludwig, A.; Ludwig, J.; Mader, W.; Marcellini, S.; Martin, A.J.; Mashimo, T.; Mattig, Peter; McKenna, J.; McPherson, R.A.; Meijers, F.; Menges, W.; Merritt, F.S.; Mes, H.; Meyer, Niels T.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Mori, T.; Mutter, A.; Nagai, K.; Nakamura, I.; Nanjo, H.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oh, A.; Oreglia, M.J.; Orito, S.; Pahl, C.; Pasztor, G.; Pater, J.R.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Pooth, O.; Przybycien, M.; Quadt, A.; Rabbertz, K.; Rembser, C.; Renkel, P.; Roney, J.M.; Rossi, A.M.; Rozen, Y.; Runge, K.; Sachs, K.; Saeki, T.; Sarkisyan, E.K.G.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schorner-Sadenius, T.; Schroder, Matthias; Schumacher, M.; Seuster, R.; Shears, T.G.; Shen, B.C.; Sherwood, P.; Skuja, A.; Smith, A.M.; Sobie, R.; Soldner-Rembold, S.; Spano, F.; Stahl, A.; Strom, David M.; Strohmer, R.; Tarem, S.; Tasevsky, M.; Teuscher, R.; Thomson, M.A.; Torrence, E.; Toya, D.; Tran, P.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Ujvari, B.; Vollmer, C.F.; Vannerem, P.; Vertesi, R.; Verzocchi, M.; Voss, H.; Vossebeld, J.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wengler, T.; Wermes, N.; Wilson, G.W.; Wilson, J.A.; Wolf, G.; Wyatt, T.R.; Yamashita, S.; Zer-Zion, D.; Zivkovic, Lidija

    2006-01-01

    Hadronic events produced in e+e- collisions by the LEP collider and recorded by the OPAL detector were used to form distributions based on the number of reconstructed jets. The data were collected between 1995 and 2000 and correspond to energies of 91 GeV, 130-136 GeV and 161-209 GeV. The jet rates were determined using four different jet-finding algorithms (Cone, JADE, Durham and Cambridge). The differential two-jet rate and the average jet rate with the Durham and Cambridge algorithms were used to measure alpha(s) in the LEP energy range by fitting an expression in which order alpah_2s calculations were matched to a NLLA prediction and fitted to the data. Combining the measurements at different centre-of-mass energies, the value of alpha_s (Mz) was determined to be alpha(s)(Mz)=0.1177+-0.0006(stat.)+-0.0012$(expt.)+-0.0010(had.)+-0.0032

  13. Bacterial expression and one-step purification of an isotope-labeled heterotrimeric G-protein {alpha}-subunit

    Energy Technology Data Exchange (ETDEWEB)

    Abdulaev, Najmoutin G. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States); Zhang Cheng; Dinh, Andy [University of Texas Health Science Center, Center for Membrane Biology, Department of Biochemistry and Molecular Biology (United States); Ngo, Tony; Bryan, Philip N. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States); Brabazon, Danielle M. [Loyola College in Maryland, Department of Chemistry (United States); Marino, John P. [University of Maryland Biotechnology Institute, Center for Advanced Research in Biotechnology (United States)], E-mail: marino@carb.nist.gov; Ridge, Kevin D. [University of Texas Health Science Center, Center for Membrane Biology, Department of Biochemistry and Molecular Biology (United States)

    2005-05-15

    Heterologous expression systems are often employed to generate sufficient quantities of isotope-labeled proteins for high-resolution NMR studies. Recently, the interaction between the prodomain region of subtilisin and an active, mutant form of the mature enzyme has been exploited to develop a cleavable affinity tag fusion system for one-step generation and purification of full-length soluble proteins obtained by inducible prokaryotic expression. As a first step towards applying high-resolution NMR methods to study heterotrimeric G-protein {alpha}-subunit (G{sub {alpha}}) conformation and dynamics, the utility of this subtilisin prodomain fusion system for expressing and purifying an isotope-labeled G{sub {alpha}} chimera ({approx}40 kDa polypeptide) has been tested. The results show that a prodomain fused G{sub {alpha}} chimera can be expressed to levels approaching 6-8 mg/l in minimal media and that the processed, mature protein exhibits properties similar to those of G{sub {alpha}} isolated from natural sources. To assay for the functional integrity of the purified G{sub {alpha}} chimera at NMR concentrations and probe for changes in the structure and dynamics of G{sub {alpha}} that result from activation, {sup 15}N-HSQC spectra of the GDP/Mg{sup 2+} bound form of G{sub {alpha}} obtained in the absence and presence of aluminum fluoride, a well known activator of the GDP bound state, have been acquired. Comparisons of the {sup 15}N-HSQC spectra reveals a number of changes in chemical shifts of the {sup 1}HN, {sup 15}N crosspeaks that are discussed with respect to expected changes in the protein conformation associated with G{sub {alpha}} activation.

  14. Coincidence study of alpha particle fragmentation at E/sub alpha/ = 140 MeV

    International Nuclear Information System (INIS)

    Koontz, R.W.

    1980-01-01

    Results of an experimental study of the interaction of 140 MeV alpha particles with 90 Zr nuclei resulting in fragmentation of the alpha particle are reported. The experimental observations of the study are analyzed and are found to show that alpha particle breakup reactions leading to at least 4-body final states, composed of two charged alpha particle fragments, contribute significantly to the singles yield of charged fragments observed at a fixed forward angle. The conclusions are based on coincidence measurements where one charged fragment is detected at a small forward angle which remains fixed, while the second charged fragment is detected at a series of coplanar secondary angles. The largest coincidence charged particle yield for the multiparticle final state events results from 90 Zr(α,pp)X reactions, where both of the measured protons have energy distributions similar to the proton singles energy distributions. The second largest observed coincidence yield involving two charged fragments arises from 90 Zr(α,pd)X reactions, where the p and d fragments, as in the 90 Zr(α,pp)X reactions also have energy distribution similar to the singles energy distributions. Analysis of additional measurements, where alpha particle fragments at the fixed angle are detected in coincidence with evaporation and nonequilibrium particles at many coplanar angles, show that the alpha particle fragmentation reactions are also generally associated with large energy transfer to the target nucleus. A multiple scattering model of the fragmentation reaction is employed, in conjunction with the experimental observations, to estimate the cross sections for alpha particle fragmentation into multi-particle final states resulting in n, 2n, p, pp, d, dn, dp, t and 3 He fragments. The estimated total cross section for all fragmentation reactions is 755 mb or approximately 38% of the total reaction cross section for 140 MeV alpha particle interactions with 90 Zr

  15. alpha-MSH and its receptors in regulation of tumor necrosis factor-alpha production by human monocyte/macrophages.

    Science.gov (United States)

    Taherzadeh, S; Sharma, S; Chhajlani, V; Gantz, I; Rajora, N; Demitri, M T; Kelly, L; Zhao, H; Ichiyama, T; Catania, A; Lipton, J M

    1999-05-01

    The hypothesis that macrophages contain an autocrine circuit based on melanocortin [ACTH and alpha-melanocyte-stimulating hormone (alpha-MSH)] peptides has major implications for neuroimmunomodulation research and inflammation therapy. To test this hypothesis, cells of the THP-1 human monocyte/macrophage line were stimulated with lipopolysaccharide (LPS) in the presence and absence of alpha-MSH. The inflammatory cytokine tumor necrosis factor (TNF)-alpha was inhibited in relation to alpha-MSH concentration. Similar inhibitory effects on TNF-alpha were observed with ACTH peptides that contain the alpha-MSH amino acid sequence and act on melanocortin receptors. Nuclease protection assays indicated that expression of the human melanocortin-1 receptor subtype (hMC-1R) occurs in THP-1 cells; Southern blots of RT-PCR product revealed that additional subtypes, hMC-3R and hMC-5R, also occur. Incubation of resting macrophages with antibody to hMC-1R increased TNF-alpha concentration; the antibody also markedly reduced the inhibitory influence of alpha-MSH on TNF-alpha in macrophages treated with LPS. These results in cells known to produce alpha-MSH at rest and to increase secretion of the peptide when challenged are consistent with an endogenous regulatory circuit based on melanocortin peptides and their receptors. Targeting of this neuroimmunomodulatory circuit in inflammatory diseases in which myelomonocytic cells are prominent should be beneficial.

  16. Recent developments for field monitoring of alpha-emitting contaminants in the environment

    International Nuclear Information System (INIS)

    Ahlquist, A.J.; Umbarger, C.J.; Stoker, A.K.

    1978-01-01

    The Los Alamos Scientific Laboratory has adapted two field methods to assess rapidly locations and concentrations of alpha-emitting contaminants in soil. (1) A ZnS scintillator is used for gross-alpha measurements on soil samples. Sample preparation and the calibration and detection limits of the system are discussed, and results of gross-alpha analysis are compared with results of a 239 Pu radiochemistry analysis. (2) A Phoswich detector is used as a field survey instrument because it can detect lower levels of radioactivity than the FIDLER probe. The electronics are carried in a truck and the probe is connected by an umbilical cord. The system electronics are calibrated with an energy window of 12-40 keV which allows detection of Pu, Am, Th (using daughter L X-rays of the alpha-emitters) and 137 Cs (using its daughter 32 keV X-rays). The bremsstrahlung from 90 Sr can also be detected. (author)

  17. Particle Physics Aspects of Antihydrogen Studies with ALPHA at CERN

    CERN Document Server

    Fujiwara, M.C.; Bertsche, W.; Bowe, P.D.; Bray, C.C.; Butler, E.; Cesar, C.L.; Chapman, S.; Charlton, M.; Fajans, J.; Funakoshi, R.; Gill, D.R.; Hangst, J.S.; Hardy, W.N.; Hayano, R.S.; Hayden, M.E.; Humphries, A.J.; Hydomako, R.; Jenkins, M.J.; Jorgensen, L.V.; Kurchaninov, L.; Lai, W.; Lambo, R.; Madsen, N.; Nolan, P.; Olchanski, K.; Olin, A.; Povilus, A.; Pusa, P.; Robicheaux, F.; Sarid, E.; Seif El Nasr, S.; Silveira, D.M.; Storey, J.W.; Thompson, R.I.; van der Werf, D.P.; Wasilenko, L.; Wurtele, J.S.; Yamazaki, Y.

    2008-01-01

    We discuss aspects of antihydrogen studies, that relate to particle physics ideas and techniques, within the context of the ALPHA experiment at CERN's Antiproton Decelerator facility. We review the fundamental physics motivations for antihydrogen studies, and their potential physics reach. We argue that initial spectroscopy measurements, once antihydrogen is trapped, could provide competitive tests of CPT, possibly probing physics at the Planck Scale. We discuss some of the particle detection techniques used in ALPHA. Preliminary results from commissioning studies of a partial system of the ALPHA Si vertex detector are presented, the results of which highlight the power of annihilation vertex detection capability in antihydrogen studies.

  18. EEG-based alpha neurofeedback training for mood enhancement.

    Science.gov (United States)

    Phneah, Swee Wu; Nisar, Humaira

    2017-06-01

    The aim of this paper is to develop a preliminary neurofeedback system to improve the mood of the subjects using audio signals by enhancing their alpha brainwaves. Assessment of the effect of music on the human subjects is performed using three methods; subjective assessment of mood with the help of a questionnaire, the effect on brain by analysing EEG signals, and the effect on body by physiological assessment. In this study, two experiments have been designed. The first experiment was to determine the short-term effect of music on soothing human subjects, whereas the second experiment was to determine its long-term effect. Two types of music were used in the first experiment, the favourite music selected by the participants and a relaxing music with alpha wave binaural beats. The research findings showed that the relaxing music has a better soothing effect on the participants psychologically and physiologically. However, the one-way analysis of variance (ANOVA) results showed that the short-term soothing effect of both favourite music and relaxing music was not significant in changing the mean alpha absolute power and mean physiological measures (blood pressure and heart rate) at the significance level of 0.05. The second experiment was somewhat similar to an alpha neurofeedback training whereby the participants trained their brains to produce more alpha brainwaves by listening to the relaxing music with alpha wave binaural beats for a duration of 30 min daily. The results showed that the relaxing music has a long-term psychological and physiological effect on soothing the participants, as can be observed from the increase in alpha power and decrease in physiological measures after each session of training. The training was found to be effective in increasing the alpha power significantly [F(2,12) = 11.5458 and p = 0.0016], but no significant reduction in physiological measures was observed at the significance level of 0.05.

  19. Test of the Flavour Independence of $\\alpha_{s}$ using Next-to-Leading Order Calculations for Heavy Quarks

    CERN Document Server

    Abbiendi, G.; Alexander, G.; Allison, John; Altekamp, N.; Anderson, K.J.; Anderson, S.; Arcelli, S.; Asai, S.; Ashby, S.F.; Axen, D.; Azuelos, G.; Ball, A.H.; Barberio, E.; Barlow, Roger J.; Batley, J.R.; Baumann, S.; Bechtluft, J.; Behnke, T.; Bell, Kenneth Watson; Bella, G.; Bellerive, A.; Bentvelsen, S.; Bethke, S.; Betts, S.; Biebel, O.; Biguzzi, A.; Bloodworth, I.J.; Bock, P.; Bohme, J.; Bonacorsi, D.; Boutemeur, M.; Braibant, S.; Bright-Thomas, P.; Brigliadori, L.; Brown, Robert M.; Burckhart, H.J.; Capiluppi, P.; Carnegie, R.K.; Carter, A.A.; Carter, J.R.; Chang, C.Y.; Charlton, David G.; Chrisman, D.; Ciocca, C.; Clarke, P.E.L.; Clay, E.; Cohen, I.; Conboy, J.E.; Cooke, O.C.; Couchman, J.; Couyoumtzelis, C.; Coxe, R.L.; Cuffiani, M.; Dado, S.; Dallavalle, G.Marco; Davis, R.; De Jong, S.; de Roeck, A.; Dervan, P.; Desch, K.; Dienes, B.; Dixit, M.S.; Dubbert, J.; Duchovni, E.; Duckeck, G.; Duerdoth, I.P.; Estabrooks, P.G.; Etzion, E.; Fabbri, F.; Fanfani, A.; Fanti, M.; Faust, A.A.; Fiedler, F.; Fierro, M.; Fleck, I.; Frey, A.; Furtjes, A.; Futyan, D.I.; Gagnon, P.; Gary, J.W.; Gascon-Shotkin, S.M.; Gaycken, G.; Geich-Gimbel, C.; Giacomelli, G.; Giacomelli, P.; Gibson, V.; Gibson, W.R.; Gingrich, D.M.; Glenzinski, D.; Goldberg, J.; Gorn, W.; Grandi, C.; Graham, K.; Gross, E.; Grunhaus, J.; Gruwe, M.; Hajdu, C.; Hanson, G.G.; Hansroul, M.; Hapke, M.; Harder, K.; Harel, A.; Hargrove, C.K.; Harin-Dirac, M.; Hauschild, M.; Hawkes, C.M.; Hawkings, R.; Hemingway, R.J.; Herndon, M.; Herten, G.; Heuer, R.D.; Hildreth, M.D.; Hill, J.C.; Hobson, P.R.; Hocker, James Andrew; Hoffman, Kara Dion; Homer, R.J.; Honma, A.K.; Horvath, D.; Hossain, K.R.; Howard, R.; Huntemeyer, P.; Igo-Kemenes, P.; Imrie, D.C.; Ishii, K.; Jacob, F.R.; Jawahery, A.; Jeremie, H.; Jimack, M.; Jones, C.R.; Jovanovic, P.; Junk, T.R.; Kanaya, N.; Kanzaki, J.; Karlen, D.; Kartvelishvili, V.; Kawagoe, K.; Kawamoto, T.; Kayal, P.I.; Keeler, R.K.; Kellogg, R.G.; Kennedy, B.W.; Kim, D.H.; Klier, A.; Kobayashi, T.; Kobel, M.; Kokott, T.P.; Kolrep, M.; Komamiya, S.; Kowalewski, Robert V.; Kress, T.; Krieger, P.; von Krogh, J.; Kuhl, T.; Kyberd, P.; Lafferty, G.D.; Landsman, H.; Lanske, D.; Lauber, J.; Lawson, I.; Layter, J.G.; Lellouch, D.; Letts, J.; Levinson, L.; Liebisch, R.; List, B.; Littlewood, C.; Lloyd, A.W.; Lloyd, S.L.; Loebinger, F.K.; Long, G.D.; Losty, M.J.; Lu, J.; Ludwig, J.; Lui, D.; Macchiolo, A.; Macpherson, A.; Mader, W.; Mannelli, M.; Marcellini, S.; Martin, A.J.; Martin, J.P.; Martinez, G.; Mashimo, T.; Mattig, Peter; McDonald, W.John; McKenna, J.; Mckigney, E.A.; McMahon, T.J.; McPherson, R.A.; Meijers, F.; Mendez-Lorenzo, P.; Merritt, F.S.; Mes, H.; Michelini, A.; Mihara, S.; Mikenberg, G.; Miller, D.J.; Mohr, W.; Montanari, A.; Mori, T.; Nagai, K.; Nakamura, I.; Neal, H.A.; Nisius, R.; O'Neale, S.W.; Oakham, F.G.; Odorici, F.; Ogren, H.O.; Okpara, A.; Oreglia, M.J.; Orito, S.; Pasztor, G.; Pater, J.R.; Patrick, G.N.; Patt, J.; Perez-Ochoa, R.; Petzold, S.; Pfeifenschneider, P.; Pilcher, J.E.; Pinfold, J.; Plane, David E.; Poffenberger, P.; Poli, B.; Polok, J.; Przybycien, M.; Quadt, A.; Rembser, C.; Rick, H.; Robertson, S.; Robins, S.A.; Rodning, N.; Roney, J.M.; Rosati, S.; Roscoe, K.; Rossi, A.M.; Rozen, Y.; Runge, K.; Runolfsson, O.; Rust, D.R.; Sachs, K.; Saeki, T.; Sahr, O.; Sang, W.M.; Sarkisian, E.K.G.; Sbarra, C.; Schaile, A.D.; Schaile, O.; Scharff-Hansen, P.; Schieck, J.; Schmitt, S.; Schoning, A.; Schroder, Matthias; Schumacher, M.; Schwick, C.; Scott, W.G.; Seuster, R.; Shears, T.G.; Shen, B.C.; Shepherd-Themistocleous, C.H.; Sherwood, P.; Siroli, G.P.; Sittler, A.; Skuja, A.; Smith, A.M.; Snow, G.A.; Sobie, R.; Soldner-Rembold, S.; Spagnolo, S.; Sproston, M.; Stahl, A.; Stephens, K.; Steuerer, J.; Stoll, K.; Strom, David M.; Strohmer, R.; Surrow, B.; Talbot, S.D.; Taras, P.; Tarem, S.; Teuscher, R.; Thiergen, M.; Thomas, J.; Thomson, M.A.; Torrence, E.; Towers, S.; Trigger, I.; Trocsanyi, Z.; Tsur, E.; Turner-Watson, M.F.; Ueda, I.; Van Kooten, Rick J.; Vannerem, P.; Verzocchi, M.; Voss, H.; Wackerle, F.; Wagner, A.; Ward, C.P.; Ward, D.R.; Watkins, P.M.; Watson, A.T.; Watson, N.K.; Wells, P.S.; Wermes, N.; Wetterling, D.; White, J.S.; Wilson, G.W.; Wilson, J.A.; Wyatt, T.R.; Yamashita, S.; Zacek, V.; Zer-Zion, D.

    1999-01-01

    We present a test of the flavour independence of the strong coupling constant for charm and bottom quarks with respect to light (uds) quarks, based on a hadronic event sample obtained with the OPAL detector at LEP. Five observables related to global event shapes were used to measure alpha_s in three flavour tagged samples (uds, c and b). The event shape distributions were fitted by Order(alpha_s**2) calculations of jet production taking into account mass effects for the c and b quarks. We find: = 0.997 +- 0.038(stat.) +- 0.030(syst.) +- 0.012(theory) and = 0.993 +- 0.008(stat.) +- 0.006(syst.) +- 0.011(theory) for the ratios alpha_s(charm)/alpha_s(uds) and alpha_s(b)/alpha_s(uds) respectively.

  20. Event-related frontal alpha asymmetries: electrophysiological correlates of approach motivation.

    Science.gov (United States)

    Schöne, Benjamin; Schomberg, Jessica; Gruber, Thomas; Quirin, Markus

    2016-02-01

    Over the last decades, frontal alpha asymmetries observed during resting state periods of several minutes have been used as a marker of affective-motivational states. To date, there is no evidence that alpha asymmetries can be observed in response to brief affective-motivational stimuli, as typically presented in event-related designs. As we argue, frontal alpha asymmetry might indeed be elicited by brief events if they are salient enough. In an event-related design, we used erotic pictures, i.e., highly salient incentives to elicit approach motivation, and contrasted them with pictures of dressed attractive women. As expected, we found significant alpha asymmetries for erotic pictures as compared to control pictures. Our findings suggest that the highly reactive reward system can lead to immediate, phasic changes in frontal alpha asymmetries. We discuss the findings with respect to the notion that high salience of erotic pictures derives from their potential of satisfying an individuals' need by mere visual inspection, which is not the case for pictures showing other types of motivational stimuli such as food.

  1. Alpha decay of {sup 181}Pb

    Energy Technology Data Exchange (ETDEWEB)

    Davids, C.N.; Henderson, D.J.; Hermann, R. [and others

    1995-08-01

    The {alpha}-decay energy of {sup 181}Pb was measured as 7211(10) keV and 7044(15). In the first study the isotope was produced in {sup 90}Zr bombardments of {sup 94}Mo and, after traversing a velocity filter, implanted in a position-sensitive Si detector; no half life for {sup 181}Pb was reported. In the second study the isotope was produced in {sup 40}Ca bombardments of {sup 144}Sm and transported to a position in front of a Si(Au) surface barrier detector with a fast He-gas-jet capillary system; an estimate of 50 ms was determined for the {sup 181}Pb half life. Recently we investigated {sup 181}Pb {alpha} decay at ATLAS as part of a survey experiment in which a l-pnA beam of 400-MeV {sup 92}Mo was used to irradiate targets of {sup 89}Y, {sup 90,92,94}Zr, and {sup 92}Mo to examine yields for one- and two-nucleon evaporation products from symmetric cold-fusion reactions. Recoiling nuclei of interest were passed through the Fragment Mass Analyzer and implanted in a double-sided silicon strip detector for {alpha}-particle assay. With the {sup 90}Zr target we observed a group at 7065(20) keV which was correlated with A = 181 recoils and had a half life of 45(20) ms. Our new results for {sup 181}Pb therefore agreed with those of the second study. There was no indication in the {sup 90}Zr + {sup 92}Mo data of the 7211(10)-keV {alpha} particles seen by Keller et al. The interested reader is referred to the 1993 atomic mass evaluation wherein the input {alpha}-decay energies and resultant masses of the light Pb isotopes (including {sup 181}Pb) are discussed.

  2. Classification of alpha 1-adrenoceptor subtypes

    NARCIS (Netherlands)

    Michel, M. C.; Kenny, B.; Schwinn, D. A.

    1995-01-01

    Two alpha 1-adrenoceptor subtypes (alpha 1A and alpha 1B) have been detected in various tissues by pharmacological techniques, and three distinct cDNAs encoding alpha 1-adrenoceptor subtypes have been cloned. The profile of an increasing number of subtype-selective compounds at cloned and endogenous

  3. Liquid scintillation alpha spectrometry techniques

    International Nuclear Information System (INIS)

    McKlveen, J.W.; McDowell, W.J.

    1984-01-01

    Accurate, quantitative determinations of alpha emitting nuclides by conventional plate counting methods are difficult, because of sample self-absorption problems in counting and because of non-reproducible losses in conventional sample separation methods. Liquid scintillation alpha spectrometry offers an attractive alternative with no sample self-absorption or geometry problems and with 100% counting efficiency. Sample preparation may include extraction of the alpha emitter of interest by a specific organic phase-soluble compound directly into the liquid scintillation counting medium. Detection electronics use energy and pulse-shape discrimination, to yield alpha spectra without beta and gamma background interference. Specific procedures have been developed for gross alpha, uranium, plutonium, thorium and colonium assay. Possibilities for a large number of other applications exist. Accuracy and reproducibility are typically in the 1% range. Backgrounds of the order of 0.01 cpm are readily achievable. The paper will present an overview of liquid scintillation alpha counting techniques and some of the results achieved for specific applications. (orig.)

  4. Laser scattering off of alpha particle cyclotron harmonic resonances: Annual performance report

    International Nuclear Information System (INIS)

    Aamodt, R.E.

    1988-01-01

    The active probing of burning plasmas to quantitatively determine high energy alpha particle characteristics is the main purpose of the laser and gyroton scattering program. Progress to date includes a systematic evaluation of homogeneous results, analytical study of alpha particle harmonic resonances, and investigations of finite size detection systems

  5. Eight per cent leakage of Lyman continuum photons from a compact, star-forming dwarf galaxy.

    Science.gov (United States)

    Izotov, Y I; Orlitová, I; Schaerer, D; Thuan, T X; Verhamme, A; Guseva, N G; Worseck, G

    2016-01-14

    One of the key questions in observational cosmology is the identification of the sources responsible for ionization of the Universe after the cosmic 'Dark Ages', when the baryonic matter was neutral. The currently identified distant galaxies are insufficient to fully reionize the Universe by redshift z ≈ 6 (refs 1-3), but low-mass, star-forming galaxies are thought to be responsible for the bulk of the ionizing radiation. As direct observations at high redshift are difficult for a variety of reasons, one solution is to identify local proxies of this galaxy population. Starburst galaxies at low redshifts, however, generally are opaque to Lyman continuum photons. Small escape fractions of about 1 to 3 per cent, insufficient to ionize much surrounding gas, have been detected only in three low-redshift galaxies. Here we report far-ultraviolet observations of the nearby low-mass star-forming galaxy J0925+1403. The galaxy is leaking ionizing radiation with an escape fraction of about 8 per cent. The total number of photons emitted during the starburst phase is sufficient to ionize intergalactic medium material that is about 40 times as massive as the stellar mass of the galaxy.

  6. A Search for Lyman Break Galaxies at z>8 in the NICMOS Parallel Imaging Survey

    Science.gov (United States)

    Henry, Alaina L.; Malkan, Matthew A.; Colbert, James W.; Siana, Brian; Teplitz, Harry I.; McCarthy, Patrick; Yan, Lin

    2007-02-01

    We have selected 14 J-dropout Lyman break galaxy (LBG) candidates with J110-H160>=2.5 from the NICMOS Parallel Imaging Survey. This survey consists of 135 arcmin2 of imaging in 228 independent sight lines, reaching average 5 σ sensitivities of J110=25.8 and H160=25.6 (AB). Distinguishing these candidates from dust-reddened star-forming galaxies at z~2-3 is difficult and will require longer wavelength observations. We consider the likelihood that any J-dropout LBGs exist in this survey and find that if L*z=9.5 is significantly brighter than L*z=6 (a factor of 4), then a few J-dropout LBGs are likely. A similar increase in luminosity has been suggested by Eyles et al. and Yan et al., but the magnitude of this increase is uncertain. Based on observations made with the NASA/ESA Hubble Space Telescope, obtained from the Space Telescope Science Institute, which is operated by the Association of Universities for Research in Astronomy, Inc., under NASA contract NAS 5-26555. These observations are associated with proposals 9484, 9865, and 10226.

  7. FORTRAN data files transference from VAX/VMS to ALPHA/UNIX; Traspaso de ficheros FORTRAN de datos de VAX/VMS a ALPHA/UNIX

    Energy Technology Data Exchange (ETDEWEB)

    Sanchez, E.; Milligen, B. Ph van [CIEMAT (Spain)

    1997-09-01

    Several tools have been developed to access the TJ-IU databases, which currently reside in VAX/VMS servers, from the TJ-II Data Acquisition System DEC ALPHA 8400 server. The TJ-I/TJ-IU databases are not homogeneous and contain several types of data files, namely, SADE, CAMAC and FORTRAN unformatted files. The tools presented in this report allow one to transfer CAMAC and those FORTRAN unformatted files defined herein, from a VAX/VMS server, for data manipulation on the ALPHA/Digital UNIX server. (Author)

  8. Two food-borne heterocyclic amines: Metabolism and DNA adduct formation of amino-alpha-carbolines

    DEFF Research Database (Denmark)

    Frederiksen, Hanne

    2005-01-01

    or proteins of animal or vegetable origin, furthermore they are found in many cooked foods, such as fish, meat, and chicken. The specific mutagenicity of the amino-a-carbolines are lower in the Ames Salmonella assay than other heterocyclic amines, but in rodent studies the carcinogenicity of the aminoa, alpha......The amino-alpha-carbolines 2-amino-9H-pyrido[2,3-b]indole (A alpha C) and 2-amino-3-methyl-9H-pyrido-[2,3-b]indole (MeA alpha C) are two mutagenic and carcinogenic heterocyclic amines formed during ordinary cooking. Amino-alpha-carbolines can be formed in model systems by pyrolyzing tryptophan...

  9. Transforming growth factor alpha and epidermal growth factor in laryngeal carcinomas demonstrated by immunohistochemistry

    DEFF Research Database (Denmark)

    Christensen, M E; Therkildsen, M H; Poulsen, Steen Seier

    1993-01-01

    the basal cell layer. The present investigation and our previous results confirm the existence of EGF receptors, TGF-alpha and EGF in laryngeal carcinomas. In addition, we conclude that the conditions do exist for growth factors to act through an autocrine system in poorly differentiated tumours and through......Fifteen laryngeal squamous cell carcinomas were investigated for the presence of transforming growth factor alpha (TGF-alpha) and epidermal growth factor (EGF) using immunohistochemical methods. In a recent study the same material was characterized for epidermal growth factor receptors (EGF...... receptors) which were confined predominantly to the undifferentiated cells. The expression of this growth factor system in malignant cells may play a role in carcinogenesis and/or tumour growth. All carcinomas were positive for TGF-alpha and 12 were positive for EGF. In moderately-to-well differentiated...

  10. Study of ({alpha}, {sup 3}He) and ({alpha}, t) reactions on {sup 28}Si at 45 MeV

    Energy Technology Data Exchange (ETDEWEB)

    Darshan, V.P.; Sathyavathiamma, M.P.; Ramaswamy, C.R.; Raja Rao, M.; Puttaswamy, N.G.; Banerjee, S.R.; Chintalapudi, S.N. [Dept. of Phys., Bangalore Univ. (India)

    1995-03-01

    The {sup 28}Si({alpha}, {sup 3}He){sup 29}Si, {sup 28}Si({alpha}, t){sup 29}P and Si({alpha}, {alpha})Si reactions were studied at E{sub {alpha}} = 45 MeV. Exact finite-range (EFR) DWBA analysis was carried out for the transitions to the ground state and to five excited states in {sup 29}Si and {sup 29}P. Spectroscopic strengths G were extracted for all the states and were compared with the predictions from shell-model and quasi-particle core-coupling calculations. Similar EFR-DWBA analyses were carried out from available (unpublished) data for the {sup 28}Si({alpha}, {sup 3}He){sup 29}Si reaction at E{sub {alpha}} = 64.9 and 120 MeV, and for the {sup 28}Si({alpha}, t){sup 29}P reaction at E{sub {alpha}} = 50 and 64.9 MeV. The comparison of experimental and theoretical values of G are provided. (author)

  11. STAR FORMATION FROM DLA GAS IN THE OUTSKIRTS OF LYMAN BREAK GALAXIES AT z ∼ 3

    International Nuclear Information System (INIS)

    Rafelski, Marc; Wolfe, Arthur M.; Chen, Hsiao-Wen

    2011-01-01

    We present evidence for spatially extended low surface brightness emission around Lyman break galaxies (LBGs) in the V-band image of the Hubble Ultra Deep Field, corresponding to the z ∼ 3 rest-frame far-UV (FUV) light, which is a sensitive measure of star formation rates (SFRs). We find that the covering fraction of molecular gas at z ∼ 3 is not adequate to explain the emission in the outskirts of LBGs, while the covering fraction of neutral atomic-dominated hydrogen gas at high redshift is sufficient. We develop a theoretical framework to connect this emission around LBGs to the expected emission from neutral H I gas, i.e., damped Lyα systems (DLAs), using the Kennicutt-Schmidt (KS) relation. Working under the hypothesis that the observed FUV emission in the outskirts of LBGs is from in situ star formation in atomic-dominated hydrogen gas, the results suggest that the SFR efficiency in such gas at z ∼ 3 is between factors of 10 and 50 lower than predictions based on the local KS relation. The total SFR density in atomic-dominated gas at z ∼ 3 is constrained to be ∼10% of that observed from the inner regions of LBGs. In addition, the metals produced by in situ star formation in the outskirts of LBGs yield metallicities comparable to those of DLAs, which is a possible solution to the 'Missing Metals' problem for DLAs. Finally, the atomic-dominated gas in the outskirts of galaxies at both high and low redshifts has similar reduced SFR efficiencies and is consistent with the same power law.

  12. alpha AD alpha hybrids of Cryptococcus neoformans: evidence of same-sex mating in nature and hybrid fitness.

    Directory of Open Access Journals (Sweden)

    Xiaorong Lin

    2007-10-01

    Full Text Available Cryptococcus neoformans is a ubiquitous human fungal pathogen that causes meningoencephalitis in predominantly immunocompromised hosts. The fungus is typically haploid, and sexual reproduction involves two individuals with opposite mating types/sexes, alpha and a. However, the overwhelming predominance of mating type (MAT alpha over a in C. neoformans populations limits alpha-a mating in nature. Recently it was discovered that C. neoformans can undergo same-sex mating under laboratory conditions, especially between alpha isolates. Whether same-sex mating occurs in nature and contributes to the current population structure was unknown. In this study, natural alpha AD alpha hybrids that arose by fusion between two alpha cells of different serotypes (A and D were identified and characterized, providing definitive evidence that same-sex mating occurs naturally. A novel truncated allele of the mating-type-specific cell identity determinant SXI1 alpha was also identified as a genetic factor likely involved in this process. In addition, laboratory-constructed alpha AD alpha strains exhibited hybrid vigor both in vitro and in vivo, providing a plausible explanation for their relative abundance in nature despite the fact that AD hybrids are inefficient in meiosis/sporulation and are trapped in the diploid state. These findings provide insights on the origins, genetic mechanisms, and fitness impact of unisexual hybridization in the Cryptococcus population.

  13. Plasma alpha-defensin is associated with cardiovascular morbidity and mortality in type 1 diabetic patients

    DEFF Research Database (Denmark)

    Joseph, G.; Tarnow, L.; Astrup, A.S.

    2008-01-01

    CONTEXT: alpha-Defensins are antimicrobial peptides of the innate immune system. In addition, experimental evidence suggests that alpha-defensins are proatherogenic. OBJECTIVE: The objective of the study was to examine the predictive value of plasma alpha-defensin as a clinical marker of cardiova...... to the development of CVD or an innocent bystander Udgivelsesdato: 2008/4...

  14. Biochemical characterization of CK2alpha and alpha' paralogues and their derived holoenzymes: evidence for the existence of a heterotrimeric CK2alpha'-holoenzyme forming trimeric complexes

    DEFF Research Database (Denmark)

    Olsen, Birgitte; Rasmussen, Tine; Niefind, Karsten

    2008-01-01

    Altogether 2 holoenzymes and 4 catalytic CK2 constructs were expressed and characterized i.e. CK2alpha (2) (1-335) beta(2); CK2alpha'-derived holoenzyme; CK2alpha(1-335); MBP-CK2alpha'; His-tagged CK2alpha and His-tagged CK2alpha'. The two His-tagged catalytic subunits were expressed in insect...... cells, all others in Escherichia coli. IC(50) studies involving the established CK2 inhibitors DMAT, TBBt, TBBz, apigenin and emodin were carried out and the K(i) values calculated. Although the differences in the K(i) values found were modest, there was a general tendency showing that the CK2...... holoenzymes were more sensitive towards the inhibitors than the free catalytic subunits. Thermal inactivation experiments involving the individual catalytic subunits showed an almost complete loss of activity after only 2 min at 45 degrees C. In the case of the two holoenzymes, the CK2alpha...

  15. Cellular localization of transforming growth factor-alpha mRNA in rat forebrain.

    Science.gov (United States)

    Seroogy, K B; Lundgren, K H; Lee, D C; Guthrie, K M; Gall, C M

    1993-05-01

    The cellular localization of transforming growth factor-alpha (TGF alpha) mRNA in juvenile and adult rat forebrain was examined using in situ hybridization with a 35S-labeled cRNA probe. TGF alpha cRNA-labeled neuronal perikarya were distributed across many forebrain regions including the olfactory bulb, caudate-putamen, nucleus accumbens, olfactory tubercle, ventral pallidum, amygdala, hippocampal stratum granulosum and CA3 stratum pyramidale, and piriform, entorhinal, and retrosplenial cortices. TGF alpha cRNA-hybridizing cells were also localized to several thalamic nuclei and to the suprachiasmatic, dorsomedial, and ventromedial nuclei of the hypothalamus. In addition, labeled cells were present in regions of white matter including the corpus callosum, anterior commissure, internal and external capsules, optic tract, and lateral olfactory tract. Thus, both neurons and glia appear to synthesize TGF alpha in normal brain. Hybridization densities were greater in neuronal fields at 2 weeks of age compared with the adult, suggesting a role for TGF alpha in the development of several forebrain systems. Our results demonstrating the prominent and wide-spread expression of TGF alpha mRNA in forebrain, combined with the extremely low abundance of epidermal growth factor mRNA in brain, support the argument that TGF alpha is the principal endogenous ligand for the epidermal growth factor receptor in normal brain.

  16. Flavonoids-induced accumulation of hypoxia-inducible factor (HIF)-1alpha/2alpha is mediated through chelation of iron.

    Science.gov (United States)

    Park, Sung-Soo; Bae, Insoo; Lee, Yong J

    2008-04-15

    Hypoxia-inducible factor-1 alpha (HIF-1alpha) is the regulatory subunit of the heterodimeric transcription factor HIF-1 that is the key regulator of cellular response to low oxygen tension. Under normoxic conditions, HIF-1alpha is continuously degraded by the ubiquitin-proteasome pathway through pVHL (von Hippel-Lindau tumor suppressor protein). Under hypoxic conditions, HIF-1alpha is stabilized and induces the transcription of HIF-1 target genes. Quercetin, a flavonoid with anti-oxidant, anti-inflammatory, and kinase modulating properties, has been found to induce HIF-1alpha accumulation and VEGF secretion in normoxia. In this study, the molecular mechanisms of quercetin-mediated HIF-1alpha accumulation were investigated. Previous studies have shown that, in addition to being induced by hypoxia, HIF-1alpha can be induced through the phosphatidylinositol 3-kinase (PI3K)/Akt and p53 signaling pathways. But our study revealed, through p53 mutant-type as well as p53 null cell lines, that neither the PI3K/Akt nor the p53 signaling pathway is required for quercetin-induced HIF-1alpha accumulation. And we observed that HIF-1alpha accumulated by quercetin is not ubiquitinated and the interaction of HIF-1alpha with pVHL is reduced, compared with HIF-1alpha accumulated by the proteasome inhibitor MG132. The use of quercetin's analogues showed that only quercetin and galangin induce HIF-1/2alpha accumulation and this effect is completely reversed by additional iron ions. This is because quercetin and galangin are able to chelate cellular iron ions that are cofactors of HIF-1/2alpha proline hydroxylase (PHD). These data suggest that quercetin inhibits the ubiquitination of HIF-1/2alpha in normoxia by hindering PHD through chelating iron ions.

  17. Free hydrogen atom collision cross sections of interest in controlled thermonuclear research

    Energy Technology Data Exchange (ETDEWEB)

    Fite, W L [John Jay Hopkins Laboratory for Pure and Applied Science, General Atomic Division of General Dynamics Corporation, San Diego, CA (United States)

    1958-07-01

    The present paper summarizes the results of measurements of the cross sections of hydrogen atoms for: (1) ionization, (2) excitation of Lyman alpha radiation on electron impact, and (3) elastic scattering of electrons of energy less than 10 eV; and also describes the approach of measurements now in progress on (4) charge-exchange between deuterons and deuterium atoms and (5) ionization of the hydrogen atom on proton impact.

  18. Gamma power is phase-locked to posterior alpha activity.

    Directory of Open Access Journals (Sweden)

    Daria Osipova

    Full Text Available Neuronal oscillations in various frequency bands have been reported in numerous studies in both humans and animals. While it is obvious that these oscillations play an important role in cognitive processing, it remains unclear how oscillations in various frequency bands interact. In this study we have investigated phase to power locking in MEG activity of healthy human subjects at rest with their eyes closed. To examine cross-frequency coupling, we have computed coherence between the time course of the power in a given frequency band and the signal itself within every channel. The time-course of the power was calculated using a sliding tapered time window followed by a Fourier transform. Our findings show that high-frequency gamma power (30-70 Hz is phase-locked to alpha oscillations (8-13 Hz in the ongoing MEG signals. The topography of the coupling was similar to the topography of the alpha power and was strongest over occipital areas. Interestingly, gamma activity per se was not evident in the power spectra and only became detectable when studied in relation to the alpha phase. Intracranial data from an epileptic subject confirmed these findings albeit there was slowing in both the alpha and gamma band. A tentative explanation for this phenomenon is that the visual system is inhibited during most of the alpha cycle whereas a burst of gamma activity at a specific alpha phase (e.g. at troughs reflects a window of excitability.

  19. Salivary Alpha-Amylase Correlates with Subjective Heat Pain Perception.

    Science.gov (United States)

    Wittwer, Amrei; Krummenacher, Peter; La Marca, Roberto; Ehlert, Ulrike; Folkers, Gerd

    2016-06-01

    Self-reports of pain are important for an adequate therapy. This is a problem with patients and infants who are restricted in providing an accurate verbal estimation of their pain. Reliable, real-time, economical, and non-invasive physiological correlates might contribute to a more comprehensive description of pain. Salivary alpha-amylase constitutes one candidate biomarker, which reflects predominantly sympathetic nervous system alterations under stressful conditions and can be measured non-invasively. The current study investigated the effects of acute heat pain on salivary alpha-amylase activity. Heat pain tolerance was measured on the non-dominant forearm. Participants completed visual analog scales on pain intensity and unpleasantness. Saliva samples were collected directly after pain induction. Twenty-seven healthy volunteers were recruited for this study. While salivary alpha-amylase levels correlated positively with intensity and unpleasantness ratings in response to acute heat pain stimuli, there was no corresponding association with pain tolerance. Salivary alpha-amylase is suggested to be an indirect physiologic correlate of subjective heat pain perception. Future studies should address the role of salivary alpha-amylase depending on the origin of pain, the concerned tissue, and other pain assessment methods. © 2016 American Academy of Pain Medicine. All rights reserved. For permissions, please e-mail: journals.permissions@oup.com.

  20. HIF-1alpha and HIF-2alpha are differentially activated in distinct cell populations in retinal ischaemia.

    Directory of Open Access Journals (Sweden)

    Freya M Mowat

    2010-06-01

    Full Text Available Hypoxia plays a key role in ischaemic and neovascular disorders of the retina. Cellular responses to oxygen are mediated by hypoxia-inducible transcription factors (HIFs that are stabilised in hypoxia and induce the expression of a diverse range of genes. The purpose of this study was to define the cellular specificities of HIF-1alpha and HIF-2alpha in retinal ischaemia, and to determine their correlation with the pattern of retinal hypoxia and the expression profiles of induced molecular mediators.We investigated the tissue distribution of retinal hypoxia during oxygen-induced retinopathy (OIR in mice using the bio-reductive drug pimonidazole. We measured the levels of HIF-1alpha and HIF-2alpha proteins by Western blotting and determined their cellular distribution by immunohistochemistry during the development of OIR. We measured the temporal expression profiles of two downstream mediators, vascular endothelial growth factor (VEGF and erythropoietin (Epo by ELISA. Pimonidazole labelling was evident specifically in the inner retina. Labelling peaked at 2 hours after the onset of hypoxia and gradually declined thereafter. Marked binding to Müller glia was evident during the early hypoxic stages of OIR. Both HIF-1alpha and HIF-2alpha protein levels were significantly increased during retinal hypoxia but were evident in distinct cellular distributions; HIF-1alpha stabilisation was evident in neuronal cells throughout the inner retinal layers whereas HIF-2alpha was restricted to Müller glia and astrocytes. Hypoxia and HIF-alpha stabilisation in the retina were closely followed by upregulated expression of the downstream mediators VEGF and EPO.Both HIF-1alpha and HIF-2alpha are activated in close correlation with retinal hypoxia but have contrasting cell specificities, consistent with differential roles in retinal ischaemia. Our findings suggest that HIF-2alpha activation plays a key role in regulating the response of Müller glia to hypoxia.

  1. Application of four anti-human interferon-alpha monoclonal antibodies for immunoassay and comparative analysis of natural interferon-alpha mixtures

    International Nuclear Information System (INIS)

    Andersson, G.; Lundgren, E.; Ekre, H.P.

    1991-01-01

    Four different mouse monoclonal antibodies to human interferon-alpha (IFN-alpha) were evaluated for application in quantitative and comparative analysis of natural IFN-alpha mixtures. Binding to IFN-alpha subtypes in solution revealed individual reactivity patterns. These patterns changed if the IFN-alpha molecules were immobilized either passively to a surface or bound by another antibody. Also, substitution of a single amino acid in IFN-alpha 2 affected the binding, apparently by altering the conformation. Isoelectric focusing of three natural IFN-alpha preparations from different sources, followed by immunoblotting, resulted in individual patterns with each of the four mAbs and also demonstrated variation in the composition of the IFN-alpha preparations. None of the mAbs was subtype specific, but by combining the different mAbs, and also applying polyclonal anti-human IFN-alpha antibodies, it was possible to design sensitive sandwich ELISAs with broad or more limited IFN-alpha subtype specificity

  2. Alpha and beta detection and spectrometry

    International Nuclear Information System (INIS)

    Saro, S.

    1984-01-01

    The theory of alpha and beta radioactive decay, the interaction of alpha and beta particles with matter, and their detection and spectrometry are dealt with in seven chapters: 1. Alpha transformation of atomic nuclei; 2. Basic properties of detectors and statistics of detection; 3. Alpha detectors and spectrometers; 4. Applications of alpha detection and spectrometry; 5. Beta transformation of atomic nuclei; 6. Beta particle detectors and spectrometers; 7. Detection of low energy beta particles. Chapter 8 is devoted to sampling and preparation of samples for radiometry. (E.F.)

  3. The alpha effect

    International Nuclear Information System (INIS)

    Anon.

    1982-01-01

    Much of the recent interest in RAM system reliability stems from concern over alpha particle soft error rates reported for the initial 64 k RAMs. With increasing memory density likely in the next few years the problem of soft errors is rearing its head again. A few years ago ITT carried out experiments on 16k RAMs and found no significant problems. However, recent tests have shown a raise in the number of soft errors with 64k RAMs, and the launch of 256k and 512k memories is likely to make the problem acute

  4. HNF4alpha dysfunction as a molecular rational for cyclosporine induced hypertension.

    Science.gov (United States)

    Niehof, Monika; Borlak, Jürgen

    2011-01-27

    Induction of tolerance against grafted organs is achieved by the immunosuppressive agent cyclosporine, a prominent member of the calcineurin inhibitors. Unfortunately, its lifetime use is associated with hypertension and nephrotoxicity. Several mechanism for cyclosporine induced hypertension have been proposed, i.e. activation of the sympathetic nervous system, endothelin-mediated systemic vasoconstriction, impaired vasodilatation secondary to reduction in prostaglandin and nitric oxide, altered cytosolic calcium translocation, and activation of the renin-angiotensin system (RAS). In this regard the molecular basis for undue RAS activation and an increased signaling of the vasoactive oligopeptide angiotensin II (AngII) remain elusive. Notably, angiotensinogen (AGT) is the precursor of AngII and transcriptional regulation of AGT is controlled by the hepatic nuclear factor HNF4alpha. To better understand the molecular events associated with cyclosporine induced hypertension, we investigated the effect of cyclosporine on HNF4alpha expression and activity and searched for novel HNF4alpha target genes among members of the RAS cascade. Using bioinformatic algorithm and EMSA bandshift assays we identified angiotensin II receptor type 1 (AGTR1), angiotensin I converting enzyme (ACE), and angiotensin I converting enzyme 2 (ACE2) as genes targeted by HNF4alpha. Notably, cyclosporine represses HNF4alpha gene and protein expression and its DNA-binding activity at consensus sequences to AGT, AGTR1, ACE, and ACE2. Consequently, the gene expression of AGT, AGTR1, and ACE2 was significantly reduced as evidenced by quantitative real-time RT-PCR. While RAS is composed of a sophisticated interplay between multiple factors we propose a decrease of ACE2 to enforce AngII signaling via AGTR1 to ultimately result in vasoconstriction and hypertension. Taken collectively we demonstrate cyclosporine to repress HNF4alpha activity through calcineurin inhibitor mediated inhibition of nuclear

  5. HNF4alpha dysfunction as a molecular rational for cyclosporine induced hypertension.

    Directory of Open Access Journals (Sweden)

    Monika Niehof

    Full Text Available Induction of tolerance against grafted organs is achieved by the immunosuppressive agent cyclosporine, a prominent member of the calcineurin inhibitors. Unfortunately, its lifetime use is associated with hypertension and nephrotoxicity. Several mechanism for cyclosporine induced hypertension have been proposed, i.e. activation of the sympathetic nervous system, endothelin-mediated systemic vasoconstriction, impaired vasodilatation secondary to reduction in prostaglandin and nitric oxide, altered cytosolic calcium translocation, and activation of the renin-angiotensin system (RAS. In this regard the molecular basis for undue RAS activation and an increased signaling of the vasoactive oligopeptide angiotensin II (AngII remain elusive. Notably, angiotensinogen (AGT is the precursor of AngII and transcriptional regulation of AGT is controlled by the hepatic nuclear factor HNF4alpha. To better understand the molecular events associated with cyclosporine induced hypertension, we investigated the effect of cyclosporine on HNF4alpha expression and activity and searched for novel HNF4alpha target genes among members of the RAS cascade. Using bioinformatic algorithm and EMSA bandshift assays we identified angiotensin II receptor type 1 (AGTR1, angiotensin I converting enzyme (ACE, and angiotensin I converting enzyme 2 (ACE2 as genes targeted by HNF4alpha. Notably, cyclosporine represses HNF4alpha gene and protein expression and its DNA-binding activity at consensus sequences to AGT, AGTR1, ACE, and ACE2. Consequently, the gene expression of AGT, AGTR1, and ACE2 was significantly reduced as evidenced by quantitative real-time RT-PCR. While RAS is composed of a sophisticated interplay between multiple factors we propose a decrease of ACE2 to enforce AngII signaling via AGTR1 to ultimately result in vasoconstriction and hypertension. Taken collectively we demonstrate cyclosporine to repress HNF4alpha activity through calcineurin inhibitor mediated inhibition

  6. Human alpha-N-acetylgalactosaminidase (alpha-NAGA) deficiency: no association with neuroaxonal dystrophy?

    NARCIS (Netherlands)

    Bakker, H. D.; de Sonnaville, M. L.; Vreken, P.; Abeling, N. G.; Groener, J. E.; Keulemans, J. L.; van Diggelen, O. P.

    2001-01-01

    Two new individuals with alpha-NAGA deficiency are presented. The index patient, 3 years old, has congenital cataract, slight motor retardation and secondary demyelinisation. Screening of his sibs revealed an alpha-NAGA deficiency in his 7-year-old healthy brother who had no clinical or neurological

  7. alpha7 and non-alpha7 nicotinic acetylcholine receptors modulate dopamine release in vitro and in vivo in the rat prefrontal cortex.

    Science.gov (United States)

    Livingstone, Phil D; Srinivasan, Jayaraman; Kew, James N C; Dawson, Lee A; Gotti, Cecilia; Moretti, Milena; Shoaib, Mohammed; Wonnacott, Susan

    2009-02-01

    Nicotine enhances attentional and working memory aspects of executive function in the prefrontal cortex (PFC) where dopamine plays a major role. Here, we have determined the nicotinic acetylcholine receptor (nAChR) subtypes that can modulate dopamine release in rat PFC using subtype-selective drugs. Nicotine and 5-Iodo-A-85380 (beta2* selective) elicited [(3)H]dopamine release from both PFC and striatal prisms in vitro and dopamine overflow from medial PFC in vivo. Blockade by dihydro-beta-erythroidine supports the participation of beta2* nAChRs. However, insensitivity of nicotine-evoked [(3)H]dopamine release to alpha-conotoxin-MII in PFC prisms suggests no involvement of alpha6beta2* nAChRs, in contrast to the striatum, and this distinction is supported by immunoprecipitation of nAChR subunits from these tissues. The alpha7 nAChR-selective agonists choline and Compound A also promoted dopamine release from PFC in vitro and in vivo, and their effects were enhanced by the alpha7 nAChR-selective allosteric potentiator PNU-120596 and blocked by specific antagonists. DNQX and MK801 inhibited [(3)H]dopamine release evoked by choline and PNU-120596, suggesting crosstalk between alpha7 nAChRs, glutamate and dopamine in the PFC. In vivo, systemic (but not local) administration of PNU-120596, in the absence of agonist, facilitated dopamine overflow in the medial PFC, consistent with the activation of extracortical alpha7 nAChRs by endogenous acetylcholine or choline. These data establish that both beta2* and alpha7 nAChRs can modulate dopamine release in the PFC in vitro and in vivo. Through their distinct actions on dopamine release, these nAChR subtypes could contribute to executive function, making them specific therapeutic targets for conditions such as schizophrenia and attention deficit hyperactivity disorder.

  8. Applying alpha-channeling to mirror machines

    Energy Technology Data Exchange (ETDEWEB)

    Zhmoginov, A. I.; Fisch, N. J. [Department of Astrophysical Sciences, Princeton University, Princeton, New Jersey 08544 (United States)

    2012-05-15

    The {alpha}-channeling effect entails the use of radio-frequency waves to expel and cool high-energetic {alpha} particles born in a fusion reactor; the device reactivity can then be increased even further by redirecting the extracted energy to fuel ions. Originally proposed for tokamaks, this technique has also been shown to benefit open-ended fusion devices. Here, the fundamental theory and practical aspects of {alpha} channeling in mirror machines are reviewed, including the influence of magnetic field inhomogeneity and the effect of a finite wave region on the {alpha}-channeling mechanism. For practical implementation of the {alpha}-channeling effect in mirror geometry, suitable contained weakly damped modes are identified. In addition, the parameter space of candidate waves for implementing the {alpha}-channeling effect can be significantly extended through the introduction of a suitable minority ion species that has the catalytic effect of moderating the transfer of power from the {alpha}-channeling wave to the fuel ions.

  9. STELLAR POPULATIONS OF LYMAN BREAK GALAXIES AT z {approx_equal} 1-3 IN THE HST/WFC3 EARLY RELEASE SCIENCE OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Hathi, N. P.; McCarthy, P. J. [Observatories of the Carnegie Institution for Science, Pasadena, CA 91101 (United States); Cohen, S. H.; Windhorst, R. A.; Rutkowski, M. J. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287-1404 (United States); Ryan, R. E. Jr.; Koekemoer, A. M.; Bond, H. E. [Space Telescope Science Institute, Baltimore, MD 21218 (United States); Finkelstein, S. L. [Department of Astronomy, University of Texas, Austin, TX 78712 (United States); Yan, H. [Department of Physics and Astronomy, University of Missouri, Columbia, MO 65211 (United States); O' Connell, R. W. [Department of Astronomy, University of Virginia, Charlottesville, VA 22904-4325 (United States); Straughn, A. N.; Kimble, R. A. [NASA-Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Balick, B. [Department of Astronomy, University of Washington, Seattle, WA 98195-1580 (United States); Calzetti, D. [Department of Astronomy, University of Massachusetts, Amherst, MA 01003 (United States); Disney, M. J. [School of Physics and Astronomy, Cardiff University, Cardiff CF24 3AA (United Kingdom); Dopita, M. A. [Research School of Astronomy and Astrophysics, Australian National University, Weston Creek, ACT 2611 (Australia); Frogel, Jay A. [Astronomy Department, King Abdulaziz University, P.O. Box 80203, Jeddah (Saudi Arabia); Hall, D. N. B. [Institute for Astronomy, University of Hawaii, Honolulu, HI 96822 (United States); Holtzman, J. A., E-mail: nhathi@obs.carnegiescience.edu [Department of Astronomy, New Mexico State University, Las Cruces, NM 88003 (United States); and others

    2013-03-10

    We analyze the spectral energy distributions (SEDs) of Lyman break galaxies (LBGs) at z {approx_equal} 1-3 selected using the Hubble Space Telescope (HST) Wide Field Camera 3 (WFC3) UVIS channel filters. These HST/WFC3 observations cover about 50 arcmin{sup 2} in the GOODS-South field as a part of the WFC3 Early Release Science program. These LBGs at z {approx_equal} 1-3 are selected using dropout selection criteria similar to high-redshift LBGs. The deep multi-band photometry in this field is used to identify best-fit SED models, from which we infer the following results: (1) the photometric redshift estimate of these dropout-selected LBGs is accurate to within few percent; (2) the UV spectral slope {beta} is redder than at high redshift (z > 3), where LBGs are less dusty; (3) on average, LBGs at z {approx_equal} 1-3 are massive, dustier, and more highly star forming, compared to LBGs at higher redshifts with similar luminosities (0.1L* {approx}< L {approx}< 2.5L*), though their median values are similar within 1{sigma} uncertainties. This could imply that identical dropout selection technique, at all redshifts, finds physically similar galaxies; and (4) the stellar masses of these LBGs are directly proportional to their UV luminosities with a logarithmic slope of {approx}0.46, and star formation rates are proportional to their stellar masses with a logarithmic slope of {approx}0.90. These relations hold true-within luminosities probed in this study-for LBGs from z {approx_equal} 1.5 to 5. The star-forming galaxies selected using other color-based techniques show similar correlations at z {approx_equal} 2, but to avoid any selection biases, and for direct comparison with LBGs at z > 3, a true Lyman break selection at z {approx_equal} 2 is essential. The future HST UV surveys, both wider and deeper, covering a large luminosity range are important to better understand LBG properties and their evolution.

  10. Characterization of alpha low level waste in 118 litre drums by passive and active neutron measurements in the promethee assay system

    Energy Technology Data Exchange (ETDEWEB)

    Jallu, F.; Passard, C.; Mariani, A.; Ma, J.L.; Baudry, G.; Romeyer-Dherbey, J.; Recroix, H.; Rodriguez, M.; Loridon, J.; Denis, C. [French Atomic Energy Commission (C.E.A./Cadarache), DED/SCCD/LDMN, Durance (France); Toubon, H. [COGEMA, VELIZY-VILLACOUBLAY (France)

    2003-07-01

    This paper deals with the PROMETHEE (PROMpt, epithermal and THErmal interrogation experiment) waste assay system for alpha low level waste (LLW) characterization. This device, including both passive and active neutron measurement methods, is developed at the French Atomic Energy Commission (C.E.A.), Cadarache Centre, in cooperation with COGEMA. Its purpose is to reach the requirements for incinerating alpha waste (less than 50 Bq[{alpha}], i.e. about 50 {mu}g of Pu per gram of raw waste) in 118 litre-<> drums. The PROMETHEE development and progress are performed with the help of simulation based on the Monte Carlo code MCNP4 [1]. These calculations are coupled with specific experiments in order to confirm calculated results and to obtain characteristics that can not be approached by the simulation (background for example). This paper presents the PROMETHEE measurement cell, its current performances, and studies performed at the laboratory about the most limiting parameters such as the matrix of the drum - its composition (H, Cl..), its density and its heterogeneity degree -the localization and the self-shielding properties of the contaminant. (orig.)

  11. DT results of TFTR's alpha collector

    International Nuclear Information System (INIS)

    Herrmann, H.W.; Zweben, S.J.; Darrow, D.S.; Timberlake, J.R.; Macaulay-Newcombe, R.G.

    1996-01-01

    An escaping alpha collector probe has been developed for TFTR's DT phase to complement the results of the lost alpha scintillator detectors which have been operating on TFTR since 1988. Measurements of the energy distribution of escaping alphas have been made by measuring the range of alphas implanted into nickel foils located within the alpha collector. Exposed samples have been analyzed for 4 DT plasma discharges at plasma currents of 1.0 and 1.8 MA. The results at 1.0 MA are in good agreement with predictions for first orbit alpha loss at 3.5 MeV. The 1.8 MA results, however, indicate a large anomalous loss of partially thermalized alphas at an energy ∼30% below the birth energy and at a total fluence nearly an order of magnitude above expected first orbit loss. This anomalous loss is not observed with the lost alpha scintillator detectors in DT plasmas but does resemble the anomalous delayed loss seen in DD plasmas. Several potential explanations for this loss process are examined. None of the candidate explanations proposed thus far are fully consistent with the anomalous loss observations

  12. An Anomaly in the Inglis-Teller Limits of the C VI Lyman and Balmer Series in Laser-Produced Plasmas

    Science.gov (United States)

    Elton, R.; Iglesias, E.; Griem, H.; Weaver, J.; Pien, G.; Mancini, R.

    2002-11-01

    Soft x-ray spectra from thin carbon layers heated by the OMEGA and NIKE lasers have been obtained with both spherical and planar targets, respectively, using a flat-field grazing incidence spectrograph equipped with a gated microchannel plate for temporal resolution. In both experiments, late-time (recombining) hydrogenic C VI spectra show an n-to-1 Lyman spectral series blending with the continuum at n=4, contrary to n=9 in the n-to-2 Balmer series. It appears unlikely that plasma inhomogeneities are the sole cause of this anomaly, given the difference in the experimental configurations. Other explanations for the line-to-continuum merging (other than the usual Stark-broadened Inglis-Teller effect) under consideration include non-thermal Doppler broadening, deviations from statistical sublevel population distributions, and opacity effects. Collisional-radiative and hydrodynamic modeling, including cascades, is employed to further understand this phenomenon.

  13. Coded aperture imaging of alpha source spatial distribution

    International Nuclear Information System (INIS)

    Talebitaher, Alireza; Shutler, Paul M.E.; Springham, Stuart V.; Rawat, Rajdeep S.; Lee, Paul

    2012-01-01

    The Coded Aperture Imaging (CAI) technique has been applied with CR-39 nuclear track detectors to image alpha particle source spatial distributions. The experimental setup comprised: a 226 Ra source of alpha particles, a laser-machined CAI mask, and CR-39 detectors, arranged inside a vacuum enclosure. Three different alpha particle source shapes were synthesized by using a linear translator to move the 226 Ra source within the vacuum enclosure. The coded mask pattern used is based on a Singer Cyclic Difference Set, with 400 pixels and 57 open square holes (representing ρ = 1/7 = 14.3% open fraction). After etching of the CR-39 detectors, the area, circularity, mean optical density and positions of all candidate tracks were measured by an automated scanning system. Appropriate criteria were used to select alpha particle tracks, and a decoding algorithm applied to the (x, y) data produced the de-coded image of the source. Signal to Noise Ratio (SNR) values obtained for alpha particle CAI images were found to be substantially better than those for corresponding pinhole images, although the CAI-SNR values were below the predictions of theoretical formulae. Monte Carlo simulations of CAI and pinhole imaging were performed in order to validate the theoretical SNR formulae and also our CAI decoding algorithm. There was found to be good agreement between the theoretical formulae and SNR values obtained from simulations. Possible reasons for the lower SNR obtained for the experimental CAI study are discussed.

  14. Improving the limits of detection of low background alpha emission measurements

    Science.gov (United States)

    McNally, Brendan D.; Coleman, Stuart; Harris, Jack T.; Warburton, William K.

    2018-01-01

    Alpha particle emission - even at extremely low levels - is a significant issue in the search for rare events (e.g., double beta decay, dark matter detection). Traditional measurement techniques require long counting times to measure low sample rates in the presence of much larger instrumental backgrounds. To address this, a commercially available instrument developed by XIA uses pulse shape analysis to discriminate alpha emissions produced by the sample from those produced by other surfaces of the instrument itself. Experience with this system has uncovered two residual sources of background: cosmogenics and radon emanation from internal components. An R&D program is underway to enhance the system and extend the pulse shape analysis technique further, so that these residual sources can be identified and rejected as well. In this paper, we review the theory of operation and pulse shape analysis techniques used in XIA's alpha counter, and briefly explore data suggesting the origin of the residual background terms. We will then present our approach to enhance the system's ability to identify and reject these terms. Finally, we will describe a prototype system that incorporates our concepts and demonstrates their feasibility.

  15. Effect of coexistent hydrogen isotopes on tracer diffusion of tritium in alpha phase of group-V metal-hydrogen systems

    International Nuclear Information System (INIS)

    Sakamoto, Kan; Hashizume, Kenichi; Sugisaki, Masayasu

    2009-01-01

    Tracer diffusion coefficients of tritium in the alpha phase of group-V metal-hydrogen systems, α-MH(D)xTy (M=V and Ta; x>>y), were measured in order to clarify the effects of coexistent hydrogen isotopes on the tritium diffusion behavior. The hydrogen concentration dependence of such behavior and the effects of the coexistent hydrogen isotopes (protium and deuterium) were determined. The results obtained in the present (for V and Ta) and previous (for Nb) studies revealed that tritium diffusion was definitely dependent on hydrogen concentration but was not so sensitive to the kind of coexistent hydrogen isotopes. By summarizing those data, it was found that the hydrogen concentration dependence of the tracer diffusion coefficient of tritium in the alpha phase of group-V metals could be roughly expressed by a single empirical curve. (author)

  16. Alpha Thalassemia (For Parents)

    Science.gov (United States)

    ... Safe Videos for Educators Search English Español Alpha Thalassemia KidsHealth / For Parents / Alpha Thalassemia What's in this ... Symptoms Diagnosis Treatment Print en español Alfa talasemia Thalassemias Thalassemias are a group of blood disorders that ...

  17. No survival of Nonlocalilty of fermionic quantum states with alpha vacuum in the infinite acceleration limit

    Energy Technology Data Exchange (ETDEWEB)

    Kwon, Younghun, E-mail: yyhkwon@hanyang.ac.kr

    2015-09-02

    In this article, we investigate the nonlocal behavior of the quantum state of fermionic system having the alpha vacuum. We evaluate the maximum violation of CHSH inequality in the quantum state. Even when the maximally entangled quantum state is initially shared it cannot violate the CHSH inequality, regardless of any alpha vacuum, when the infinite acceleration is applied. It means that the nonlocality of the quantum state in fermionic system with the alpha vacuum cannot survive in the infinite acceleration limit.

  18. Combinations of ERK and p38 MAPK inhibitors ablate tumor necrosis factor-alpha (TNF-alpha ) mRNA induction. Evidence for selective destabilization of TNF-alpha transcripts.

    Science.gov (United States)

    Rutault, K; Hazzalin, C A; Mahadevan, L C

    2001-03-02

    Tumor necrosis factor-alpha (TNF-alpha) is a potent proinflammatory cytokine whose synthesis and secretion are implicated in diverse pathologies. Hence, inhibition of TNF-alpha transcription or translation and neutralization of its protein product represent major pharmaceutical strategies to control inflammation. We have studied the role of ERK and p38 mitogen-activated protein (MAP) kinase in controlling TNF-alpha mRNA levels in differentiated THP-1 cells and in freshly purified human monocytes. We show here that it is possible to produce virtually complete inhibition of lipopolysaccharide-stimulated TNF-alpha mRNA accumulation by using a combination of ERK and p38 MAP kinase inhibitors. Furthermore, substantial inhibition is achievable using combinations of 1 microm of each inhibitor, whereas inhibitors used individually are incapable of producing complete inhibition even at high concentrations. Finally, addressing mechanisms involved, we show that inhibition of p38 MAP kinase selectively destabilizes TNF-alpha transcripts but does not affect degradation of c-jun transcripts. These results impinge on the controversy in the literature surrounding the mode of action of MAP kinase inhibitors on TNF-alpha mRNA and suggest the use of combinations of MAP kinase inhibitors as an effective anti-inflammatory strategy.

  19. Tumor necrosis factor-alpha-independent downregulation of hepatic cholesterol 7alpha-hydroxylase gene in mice treated with lead nitrate.

    Science.gov (United States)

    Kojima, Misaki; Sekikawa, Kenji; Nemoto, Kiyomitsu; Degawa, Masakuni

    2005-10-01

    We previously reported that lead nitrate (LN), an inducer of hepatic tumor necrosis factor-alpha (TNF-alpha), downregulated gene expression of cholesterol 7alpha-hydroxylase. Herein, to clarify the role of TNF-alpha in LN-induced downregulation of cholesterol 7alpha-hydroxylase, effects of LN on gene expression of hepatic cholesterol 7alpha-hydroxylase (Cyp7a1) in TNF-alpha-knockout (KO) and TNF-alpha-wild-type (WT) mice were comparatively examined. Gene expression of hepatic Cyp7a1 in both WT and KO mice decreased to less than 5% of the corresponding controls at 6-12 h after treatment with LN (100 mumol/kg body weight, iv). Levels of hepatic TNF-alpha protein in either WT or KO mice were below the detection limit, although expression levels of the TNF-alpha gene markedly increased at 6 h in WT mice by LN treatment, but not in KO mice. In contrast, in both WT and KO mice, levels of hepatic IL-1beta protein, which is known to be a suppressor of the cholesterol 7alpha-hydroxylase gene in hamsters, were significantly increased 3-6 h after LN treatment. Furthermore, LN-induced downregulation of the Cyp7a1 gene did not necessarily result from altered gene expression of hepatic transcription factors, including positive regulators (liver X receptor alpha, retinoid X receptor alpha, fetoprotein transcription factor, and hepatocyte nuclear factor 4alpha) and a negative regulator small heterodimer partner responsible for expression of the Cyp7a1 gene. The present findings indicated that LN-induced downregulation of the Cyp7a1 gene in mice did not necessarily occur through a TNF-alpha-dependent pathway and might occur mainly through an IL-1beta-dependent pathway.

  20. Reverse-phase HPLC analysis of human alpha crystallin.

    Science.gov (United States)

    Swamy, M S; Abraham, E C

    1991-03-01

    A rapid and highly sensitive reverse-phase HPLC (RP-HPLC) method was used to separate crystallin subunits from human alpha crystallin. Three distinct peaks were separated; by electrophoretic and immunological analyses the first and second peaks were identified as alpha B and alpha A respectively. On the other hand, peak 3 appeared to be a modified form of alpha crystallin. The ratio of alpha A and alpha B proteins was 3:1 in 1 day old lenses which gradually changed to 2:1 in 17 year old lenses and to 1:1 in the 50 and 82 year old whole lenses and 82 year old lens cortex, with a concomitant increase in the modified alpha, suggesting that alpha A subunits are relatively more involved in aggregation. Analysis of the 82 year old lens nucleus also supported this conclusion. The RP-HPLC analysis of the HMW aggregate fraction showed substantial enrichment of the modified alpha. The alpha A and alpha B subunits independently reassociated to form polymeric alpha crystallin whereas the modified alpha reassociated to form HMW aggregates as shown by molecular sieve HPLC. Hence it appears that the HMW aggregate peak was constituted by modified alpha crystallin. Only in the peak 3 material the 280 nm absorbance was about 2-fold higher than what was expected from the actual protein content. The data suggest that the changes induced by post-translational modifications may have some role in the formation of modified alpha. The present RP-HPLC method is useful in separating these modified alpha from the unmodified alpha A and alpha B subunits.