WorldWideScience

Sample records for d-asteroid spectral counterpart

  1. VizieR Online Data Catalog: ADAM: 3D asteroid shape reconstruction code (Viikinkoski+, 2015)

    Science.gov (United States)

    Viikinkoski, M.; Kaasalainen, M.; Durech, J.

    2015-02-01

    About the code: ADAM is a collection of routines for 3D asteroid shape reconstruction from disk-resolved observations. Any combination of lightcurves, adaptive optics images, HST/FGS data, range-Doppler radar images and disk-resolved thermal images may be used as data sources. The routines are implemented in a combination of MATLAB and C. (2 data files).

  2. Quantum experiments without classical counterparts

    International Nuclear Information System (INIS)

    Pavicic, M.

    2005-01-01

    Full text: We present a generalized and exhaustive method of finding the directions of the quantization axes of the measured eigenstates within experiments which have no classical counterparts. The method relies on a constructive and exhaustive definition of sets of such directions (which we call Kochen-Specker vectors) in a Hilbert space of any dimension as well as of all the remaining vectors of the space. Kochen-Specker vectors are elements of any set of orthonormal states, i.e., vectors in n-dim Hilbert space, Hn, n > 2 to which it is impossible to assign 1s and 0s in such a way that no two mutually orthogonal vectors from the set are both assigned 1 and that not all mutually orthogonal vectors are assigned 0. Our constructive definition of such Kochen-Specker vectors is based on algorithms that generate MMP diagrams corresponding to blocks of orthogonal vectors in Rn, on algorithms that single out those diagrams on which algebraic to 0-1 states cannot be defined, and on algorithms that solve nonlinear equations describing the orthogonalities of the vectors by means of statistically polynomially complex interval analysis and self-teaching programs. The algorithms are limited neither by the number of dimensions nor by the number of vectors. To demonstrate the power of the algorithms, all 4-dim KS vector systems containing up to 24 vectors were generated and described, all 3-dim vector systems containing up to 30 vectors were scanned, and several general properties of KS vectors were found. (author)

  3. OPTICAL COUNTERPARTS OF THE NEAREST ULTRALUMINOUS X-RAY SOURCES

    Energy Technology Data Exchange (ETDEWEB)

    Gladstone, Jeanette C.; Heinke, Craig O.; Cartwright, Taylor F. [Department of Physics, University of Alberta, 11322-89 Avenue, Edmonton, Alberta T6G 2G7 (Canada); Copperwheat, Chris [Department of Physics, Liverpool John Moores University, Wirral CH41 1LD (United Kingdom); Roberts, Timothy P. [Department of Physics, University of Durham, South Road, Durham DH1 3LE (United Kingdom); Levan, Andrew J. [Department of Physics, University of Warwick, Coventry CV4 7VL (United Kingdom); Goad, Mike R., E-mail: j.c.gladstone@ualberta.ca [Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7AL (United Kingdom)

    2013-06-01

    We present a photometric survey of the optical counterparts of ultraluminous X-ray sources (ULXs) observed with the Hubble Space Telescope (HST) in nearby ({approx}<5 Mpc) galaxies. Of the 33 ULXs with HST and Chandra data, 9 have no visible counterpart, placing limits on their M{sub V} of {approx} -4 to -9, enabling us to rule out O-type companions in 4 cases. The refined positions of two ULXs place them in the nucleus of their host galaxy. They are removed from our sample. Of the 22 remaining ULXs, 13 have one possible optical counterpart, while multiple are visible within the error regions of other ULXs. By calculating the number of chance coincidences, we estimate that 13 {+-} 5 are the true counterparts. We attempt to constrain the nature of the companions by fitting the spectral energy distribution and M{sub V} to obtain candidate spectral types. We can rule out O-type companions in 20 cases, while we find that one ULX (NGC 253 ULX2) excludes all OB-type companions. Fitting with X-ray irradiated models provides constraints on the donor star mass and radius. For seven ULXs, we are able to impose inclination-dependent upper and/or lower limits on the black holes' mass, if the extinction to the assumed companion star is not larger than the Galactic column. These are NGC 55 ULX1, NGC 253 ULX1, NGC 253 ULX2, NGC 253 XMM6, Ho IX X-1, IC342 X-1, and NGC 5204 X-1. This suggests that 10 ULXs do not have O companions, while none of the 18 fitted rule out B-type companions.

  4. ACCOUNTING TREATMENTS SPECIFIC TO COUNTERPART COMMERCIAL TRANSACTIONS

    Directory of Open Access Journals (Sweden)

    Lucia PALIU - POPA

    2010-12-01

    Full Text Available Given the lack of availability of funds in foreign currency, felt in many countries, especially in the developing and developed countries and the economic or financial crisis in the global foreign exchange, counterpart commercial transactions were imposed as a “disarming” condition of the international trade. In the counterpart a purchase transaction is combined with a sale transaction, an import with an export in order to ensure balanced trade between the partners, trade that involves eliminating or reducing the currency as a payment source and its replacement with trade of goods and services. Thus, in the context of an acute need to export of greatly industrialized countries, where the overproduction phenomenon tends to have a chronic character, the counterpart has become a highly complex and sustainable phenomenon, which has seen a steady increase in the volume of amounts, with a geographical area and large variety of forms and mechanisms of implementation. Based on the characteristics and structure of counterpart transactions, we shall describe in this paper the accounting models specific to international trade, as part of the combined foreign trade transactions without neglecting the tax treatments that influence the entry in the accounts

  5. X-ray Counterparts of Infrared Faint Radio Sources

    Science.gov (United States)

    Schartel, Norbert

    2011-10-01

    Infrared Faint Radio Sources (IFRS) are radio sources with extremely faint or even absent infrared emission in deep Spitzer Surveys. Models of their spectral energy distributions, the ratios of radio to infrared flux densities and their steep radio spectra strongly suggest that IFRS are AGN at high redshifts (2IFRS, but if confirmed, the increased AGN numbers at these redshifts will account for the unresolved part of the X-ray background. The identification of X-ray counterparts of IFRS is considered to be the smoking gun for this hypothesis. We propose to observe 8 IFRS using 30ks pointed observations. X-ray detections of IFRS with different ratios of radio-to-infrared fluxes, will constrain the class-specific SED.

  6. Electromagnetic Counterparts to Black Hole Mergers

    Science.gov (United States)

    Schnittman, Jeremy D.

    2011-01-01

    During the final moments of a binary black hole (BH) merger, the gravitational wave (GW) luminosity of the system is greater than the combined electromagnetic (EM) output of the entire observable universe. However, the extremely weak coupling between GWs and ordinary matter makes these waves very difficult to detect directly. Fortunately, the inspirating BH system will interact strongly-on a purely Newtonian level-with any surrounding material in the host galaxy, and this matter can in turn produce unique EM signals detectable at Earth. By identifying EM counterparts to GW sources, we will be able to study the host environments of the merging BHs, in turn greatly expanding the scientific yield of a mission like LISA. Here we present a comprehensive review of the recent literature on the subject of EM counterparts, as well as a discussion of the theoretical and observational advances required to fully realize the scientific potential of the field.

  7. Kilonova Counterparts of Binary Neutron Star Mergers

    Science.gov (United States)

    Metzger, Brian

    2018-01-01

    The merger of a binary neutron star is accompanied by the ejection of neutron-rich matter into space at velocities up to several tenths that of light, which synthesizes rare heavy isotopes through the rapid neutron capture process (r-process). The radioactive decay of these nuclei was predicted by Metzger et al. (2010) to power an optical transient roughly 1000 times more luminous than a classical nova (a "kilonova"), which is among the most promising electromagnetic counterparts to accompany gravitational wave signal from the merger. I will describe how the luminosities, color, and spectra of the kilonova emission inform the properties of the merging binary (neutron star masses/radii and inclination angle) and the long sought origin of the heaviest elements in the Universe. Results will be discussed in the context of recent discoveries by Advanced LIGO/Virgo.

  8. UMCP MIST counter-part test

    International Nuclear Information System (INIS)

    di Marzo, M.; Almenas, K.; Hsu, Y.Y.; Pertmer, G.A.

    1990-01-01

    Two small break loss-of-coolant accident (LOCA) transients are compared to illustrate a scaling methodology for reduced pressure integral facilities. Mapping test 3004 is conducted in the Multiloop Integral System Test (MIST) full pressure, full height facility. The counter-part test MISO3l7 is scaled and performed in the reduced height, reduced pressure UMCP facility. Inventory is used as the chronological scale and pressure, normalized with the initial and system saturation pressures, is used as characteristic parameter to describe the system behavior. The appropriately normalized results conclusively demonstrate that: (a) the same phenomena are observed in the two facilities; (b) the sequence of events is analogous and (c) the trends described by the normalized pressure versus inventory traces are in good quantitative agreement. Each energy transport mode traversed by the two facilities is compared and the phenomena present are described in detail. The differences between the high and reduced pressure tests are outlined. The findings clearly indicate that pressure and height can be scaled for transient where limited boundary conditions are applied and where the break is subcooled. A statement on sensitivity to the initial conditions is also included to define the limitations of the quantitative results

  9. Total spectral distributions from Hawking radiation

    Science.gov (United States)

    Broda, Bogusław

    2017-11-01

    Taking into account the time dependence of the Hawking temperature and finite evaporation time of the black hole, the total spectral distributions of the radiant energy and of the number of particles have been explicitly calculated and compared to their temporary (initial) blackbody counterparts (spectral exitances).

  10. Total spectral distributions from Hawking radiation

    Energy Technology Data Exchange (ETDEWEB)

    Broda, Boguslaw [University of Lodz, Department of Theoretical Physics, Faculty of Physics and Applied Informatics, Lodz (Poland)

    2017-11-15

    Taking into account the time dependence of the Hawking temperature and finite evaporation time of the black hole, the total spectral distributions of the radiant energy and of the number of particles have been explicitly calculated and compared to their temporary (initial) blackbody counterparts (spectral exitances). (orig.)

  11. A possible human counterpart of the principle of increasing entropy

    International Nuclear Information System (INIS)

    Liang, Y.; An, K.N.; Yang, G.; Huang, J.P.

    2014-01-01

    It is well-known that the principle of increasing entropy holds for isolated natural systems that contain non-adaptive molecules. Here we present, for the first time, an experimental evidence for a possible human counterpart of the principle in an isolated social system that involves adaptive humans. Our work shows that the human counterpart is valid even though interactions among humans in social systems are distinctly different from those among molecules in natural systems. Thus, it becomes possible to understand social systems from this natural principle, at least to some extent.

  12. 76 FR 61090 - Endangered and Threatened Species; Counterpart Regulations

    Science.gov (United States)

    2011-10-03

    ..., National Fire Plan Counterpart Regulation Alternative Consultation Agreements (ACAs). DATES: This is effective on October 1, 2011. ADDRESSES: The final decision of revocation is available on the internet at http://www.nmfs.noaa.gov/pr/laws/esa/policies.htm#consultation and http://www.fws.gov/endangered/esa...

  13. Search for infrared counterparts of gamma-ray bursters

    International Nuclear Information System (INIS)

    Schaefer, B.E.; Cline, T.L.

    1985-01-01

    The result of two searches for infrared counterparts of Gamma-ray Bursters (GRB's) is reported. The first search was made using data from the Infrared Astronomy Satellite and covered 23 positions. The second search was made with the Kitt Peak 1.5 m telescope and covered 3 positions. In neither of these two searches was any infrared candidate detected

  14. THE VARIABLE NEAR-INFRARED COUNTERPART OF THE MICROQUASAR GRS 1758–258

    Energy Technology Data Exchange (ETDEWEB)

    Luque-Escamilla, Pedro L. [Departamento de Ingeniería Mecánica y Minera, EPSJ, Universidad de Jaén, Campus Las Lagunillas s/n, A3-008, 23071 Jaén (Spain); Martí, Josep [Departamento de Física, EPSJ, Universidad de Jaén, Campus Las Lagunillas s/n, A3-420, 23071 Jaén (Spain); Muñoz-Arjonilla, Álvaro J., E-mail: peter@ujaen.es, E-mail: jmarti@ujaen.es, E-mail: ajmunoz@ujaen.es [Grupo de Investigación FQM-322, Universidad de Jaén, Campus Las Lagunillas s/n, A3-065, 23071 Jaén (Spain)

    2014-12-10

    We present a new study of the microquasar system GRS 1758–258 in the near-infrared domain based on archival observations with the Hubble Space Telescope and the NICMOS camera. In addition to confirming the near-infrared counterpart pointed out by Muñoz-Arjonilla et al., we show that this object displays significant photometric variability. From its average magnitudes, we also find that GRS 1758–258 fits well within the correlation between the optical/near-infrared and X-ray luminosity known to exist for low-mass, black-hole candidate X-ray binaries in a hard state. Moreover, the spectral energy distribution built using all radio, near-infrared, and X-ray data available closest in time to the NICMOS observations can be reasonably interpreted in terms of a self-absorbed radio jet and an irradiated accretion disk model around a stellar-mass black hole. All these facts match the expected behavior of a compact binary system and strengthen our confidence in the counterpart identification.

  15. Benzene and superior counterpart; Benzene et homologues superieurs

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-07-01

    A century ago, the first case of purpura and acute anemia provoked by benzene was described. Afterwards, others important toxic effects in relation with the exposure to this solvent were known: medullar aplasia, acute leukemia,carcinogenesis. The chronic intoxication by benzene is called benzenism, the term of benzolism is devoted to the intoxication provoked by the mixture of benzene and superior counterparts: toluene, xylenes. (N.C.)

  16. Electromagnetic counterparts to structured jets from gravitational wave detected mergers

    Science.gov (United States)

    Lamb, Gavin P.; Kobayashi, Shiho

    2017-12-01

    We show the peak magnitude for orphan afterglows from the jets of gravitational wave (GW) detected black hole/neutron star - neutron star (BH/NS-NS) mergers highly depend on the jet half-opening angle θj. Short γ-ray bursts (GRBs) with a homogeneous jet structure and θj > 10°, the orphan afterglow viewed at the typical inclination for a GW detected event, 38°, are brighter at optical frequencies than the comparable macronova emission. Structured jets, where the energetics and Lorentz factor Γ vary with angle from the central axis, may have low-Γ components where the prompt emission is suppressed; GW electromagnetic (EM) counterparts may reveal a population of failed-GRB orphan afterglows. Using a Monte Carlo method assuming an NS-NS detection limit we show the fraction of GW-EM counterparts from homogeneous, two-component, power-law structured and Gaussian jets where the variable structure models include a wide low energy and Γ component: for homogeneous jets, with a θj = 6° and typical short GRB parameters, we find r-band magnitude mr ≤ 21 counterparts for ∼13.6 per cent of GW detected mergers; where jet structure extends to a half-opening angle of 25°, two-component jets produce mr ≤ 21 counterparts in ∼30 per cent of GW detected mergers, power-law structured-jets result in ∼37 per cent and Gaussian jets with our parameters ∼13 per cent. We show the features in the light curves from orphan afterglows can be used to indicate the presence of extended structure.

  17. Search for Gravitational Wave Counterparts with Fermi GBM

    Science.gov (United States)

    Hui, C. M.

    2017-01-01

    The progenitor of short gamma-ray bursts (GRBs) is believed to be the merger of two compact objects. This type of events will also produce gravitational waves. Since the gravitational waves discovery by LIGO, the search for a joint detection with an electromagnetic counterpart has been ongoing. Fermi GBM detects approximately 40 short GRBs per year, and we have been expanding our search looking for faint events in the GBM data that did not trigger onboard.

  18. Seeking Counterparts to Advanced LIGO/Virgo Transients with Swift

    Science.gov (United States)

    Kanner, Jonah; Camp, Jordan; Racusin, Judith; Gehrels, Neil; White, Darren

    2012-01-01

    Binary neutron star (NS) mergers are among the most promising astrophysical sources of gravitational wave emission for Advanced LIGO and Advanced Virgo, expected to be operational in 2015 . Finding electromagnetic counterparts to these signals will be essential to placing them in an astronomical context. The Swift satellite carries a sensitive X-ray telescope (XRT), and can respond to target-of-opportunity requests within 1-2 hours, and so is uniquely poised to find the X-ray counterparts to LIGO / Virgo triggers. Assuming NS mergers are the progenitors of short gamma-ray bursts (GRBs), some percentage of LIGO/Virgo triggers will be accompanied by X-ray band afterglows that are brighter than 10(exp -12) ergs/s/sq cm in the XRT band one day after the trigger time. We find that a soft X-ray transient of this flux is bright enough to be extremely rare, and so could be confidently associated with even a moderately localized GW signal. We examine two possible search strategies with the Swift XRT to find bright transients in LIGO/Virgo error boxes. In the first strategy, XRT could search a volume of space with a approx.100 Mpc radius by observing approx 30 galaxies over the course of a day, with sufficient depth to observe the expected X-ray afterglow. For an extended LIGO / Virgo horizon distance, the XRT could employ very short 100 s exposures to cover an area of approx 35 square degrees in about a day, and still be sensitive enough to image GW discovered GRB afterglows. These strategies demonstrate that the high X-ray luminosity of short GRBs and the relatively low X-ray transient background combine to make high confidence discoveries of X-ray band counterparts to GW triggers possible, though challenging, with current satellite facilities.

  19. Spectral Pollution

    OpenAIRE

    Davies, E B; Plum, M

    2003-01-01

    We discuss the problems arising when computing eigenvalues of self-adjoint operators which lie in a gap between two parts of the essential spectrum. Spectral pollution, i.e. the apparent existence of eigenvalues in numerical computations, when no such eigenvalues actually exist, is commonplace in problems arising in applied mathematics. We describe a geometrically inspired method which avoids this difficulty, and show that it yields the same results as an algorithm of Zimmermann and Mertins.

  20. Capability of detecting ultraviolet counterparts of gravitational waves with GLUV

    Science.gov (United States)

    Ridden-Harper, Ryan; Tucker, B. E.; Sharp, R.; Gilbert, J.; Petkovic, M.

    2017-12-01

    With the discovery of gravitational waves (GWs), attention has turned towards detecting counterparts to these sources. In discussions on counterpart signatures and multimessenger follow-up strategies to the GW detections, ultraviolet (UV) signatures have largely been neglected, due to UV facilities being limited to SWIFT, which lacks high-cadence UV survey capabilities. In this paper, we examine the UV signatures from merger models for the major GW sources, highlighting the need for further modelling, while presenting requirements and a design for an effective UV survey telescope. Using the u΄-band models as an analogue, we find that a UV survey telescope requires a limiting magnitude of m_{u^' }}(AB)≈ 24 to fully complement the aLIGO range and sky localization. We show that a network of small, balloon-based UV telescopes with a primary mirror diameter of 30 cm could be capable of covering the aLIGO detection distance from ∼60 to 100 per cent for BNS events and ∼40 per cent for the black hole and a neutron star events. The sensitivity of UV emission to initial conditions suggests that a UV survey telescope would provide a unique data set, which can act as an effective diagnostic to discriminate between models.

  1. Driving protocol for a Floquet topological phase without static counterpart

    Science.gov (United States)

    Quelle, A.; Weitenberg, C.; Sengstock, K.; Morais Smith, C.

    2017-11-01

    Periodically driven systems play a prominent role in optical lattices. In these ultracold atomic systems, driving is used to create a variety of interesting behaviours, of which an important example is provided by topological states of matter. Such Floquet topological phases have a richer classification than their equilibrium counterparts. Although there exist analogues of the equilibrium topological phases that are characterised by a Chern number, the corresponding Hall conductivity, and protected edge states, there is an additional possibility. This is a phase that has a vanishing Chern number and no Hall conductivity, but nevertheless hosts anomalous topological edge states (Rudner et al (2013 Phys. Rev. X 3 031005)). Due to experimental difficulties associated with the observation of such a phase, it has not been experimentally realised in optical lattices so far. In this paper, we show that optical lattices prove to be a good candidate for its realisation and observation, because they can be driven in a controlled manner. Specifically, we present a simple shaking protocol that serves to realise this special Floquet phase, discuss the specific properties that it has, and propose a method to experimentally detect this fascinating topological phase that has no counterpart in equilibrium systems.

  2. Cat Mammary Tumors: Genetic Models for the Human Counterpart

    Directory of Open Access Journals (Sweden)

    Filomena Adega

    2016-08-01

    Full Text Available The records are not clear, but Man has been sheltering the cat inside his home for over 12,000 years. The close proximity of this companion animal, however, goes beyond sharing the same roof; it extends to the great similarity found at the cellular and molecular levels. Researchers have found a striking resemblance between subtypes of feline mammary tumors and their human counterparts that goes from the genes to the pathways involved in cancer initiation and progression. Spontaneous cat mammary pre-invasive intraepithelial lesions (hyperplasias and neoplasias and malignant lesions seem to share a wide repertoire of molecular features with their human counterparts. In the present review, we tried to compile all the genetics aspects published (i.e., chromosomal alterations, critical cancer genes and their expression regarding cat mammary tumors, which support the cat as a valuable alternative in vitro cell and animal model (i.e., cat mammary cell lines and the spontaneous tumors, respectively, but also to present a critical point of view of some of the issues that really need to be investigated in future research.

  3. A radio counterpart to a neutron star merger.

    Science.gov (United States)

    Hallinan, G; Corsi, A; Mooley, K P; Hotokezaka, K; Nakar, E; Kasliwal, M M; Kaplan, D L; Frail, D A; Myers, S T; Murphy, T; De, K; Dobie, D; Allison, J R; Bannister, K W; Bhalerao, V; Chandra, P; Clarke, T E; Giacintucci, S; Ho, A Y Q; Horesh, A; Kassim, N E; Kulkarni, S R; Lenc, E; Lockman, F J; Lynch, C; Nichols, D; Nissanke, S; Palliyaguru, N; Peters, W M; Piran, T; Rana, J; Sadler, E M; Singer, L P

    2017-12-22

    Gravitational waves have been detected from a binary neutron star merger event, GW170817. The detection of electromagnetic radiation from the same source has shown that the merger occurred in the outskirts of the galaxy NGC 4993, at a distance of 40 megaparsecs from Earth. We report the detection of a counterpart radio source that appears 16 days after the event, allowing us to diagnose the energetics and environment of the merger. The observed radio emission can be explained by either a collimated ultrarelativistic jet, viewed off-axis, or a cocoon of mildly relativistic ejecta. Within 100 days of the merger, the radio light curves will enable observers to distinguish between these models, and the angular velocity and geometry of the debris will be directly measurable by very long baseline interferometry. Copyright © 2017, American Association for the Advancement of Science.

  4. Follow Up of GW170817 and Its Electromagnetic Counterpart by Australian-Led Observing Programmes

    Science.gov (United States)

    Andreoni, I.; Ackley, K.; Cooke, J.; Acharyya, A.; Allison, J. R.; Anderson, G. E.; Ashley, M. C. B.; Baade, D.; Bailes, M.; Bannister, K.; Beardsley, A.; Bessell, M. S.; Bian, F.; Bland, P. A.; Boer, M.; Booler, T.; Brandeker, A.; Brown, I. S.; Buckley, D. A. H.; Chang, S.-W.; Coward, D. M.; Crawford, S.; Crisp, H.; Crosse, B.; Cucchiara, A.; Cupák, M.; de Gois, J. S.; Deller, A.; Devillepoix, H. A. R.; Dobie, D.; Elmer, E.; Emrich, D.; Farah, W.; Farrell, T. J.; Franzen, T.; Gaensler, B. M.; Galloway, D. K.; Gendre, B.; Giblin, T.; Goobar, A.; Green, J.; Hancock, P. J.; Hartig, B. A. D.; Howell, E. J.; Horsley, L.; Hotan, A.; Howie, R. M.; Hu, L.; Hu, Y.; James, C. W.; Johnston, S.; Johnston-Hollitt, M.; Kaplan, D. L.; Kasliwal, M.; Keane, E. F.; Kenney, D.; Klotz, A.; Lau, R.; Laugier, R.; Lenc, E.; Li, X.; Liang, E.; Lidman, C.; Luvaul, L. C.; Lynch, C.; Ma, B.; Macpherson, D.; Mao, J.; McClelland, D. E.; McCully, C.; Möller, A.; Morales, M. F.; Morris, D.; Murphy, T.; Noysena, K.; Onken, C. A.; Orange, N. B.; Osłowski, S.; Pallot, D.; Paxman, J.; Potter, S. B.; Pritchard, T.; Raja, W.; Ridden-Harper, R.; Romero-Colmenero, E.; Sadler, E. M.; Sansom, E. K.; Scalzo, R. A.; Schmidt, B. P.; Scott, S. M.; Seghouani, N.; Shang, Z.; Shannon, R. M.; Shao, L.; Shara, M. M.; Sharp, R.; Sokolowski, M.; Sollerman, J.; Staff, J.; Steele, K.; Sun, T.; Suntzeff, N. B.; Tao, C.; Tingay, S.; Towner, M. C.; Thierry, P.; Trott, C.; Tucker, B. E.; Väisänen, P.; Krishnan, V. Venkatraman; Walker, M.; Wang, L.; Wang, X.; Wayth, R.; Whiting, M.; Williams, A.; Williams, T.; Wolf, C.; Wu, C.; Wu, X.; Yang, J.; Yuan, X.; Zhang, H.; Zhou, J.; Zovaro, H.

    2017-12-01

    The discovery of the first electromagnetic counterpart to a gravitational wave signal has generated follow-up observations by over 50 facilities world-wide, ushering in the new era of multi-messenger astronomy. In this paper, we present follow-up observations of the gravitational wave event GW170817 and its electromagnetic counterpart SSS17a/DLT17ck (IAU label AT2017gfo) by 14 Australian telescopes and partner observatories as part of Australian-based and Australian-led research programs. We report early- to late-time multi-wavelength observations, including optical imaging and spectroscopy, mid-infrared imaging, radio imaging, and searches for fast radio bursts. Our optical spectra reveal that the transient source emission cooled from approximately 6 400 K to 2 100 K over a 7-d period and produced no significant optical emission lines. The spectral profiles, cooling rate, and photometric light curves are consistent with the expected outburst and subsequent processes of a binary neutron star merger. Star formation in the host galaxy probably ceased at least a Gyr ago, although there is evidence for a galaxy merger. Binary pulsars with short (100 Myr) decay times are therefore unlikely progenitors, but pulsars like PSR B1534+12 with its 2.7 Gyr coalescence time could produce such a merger. The displacement ( 2.2 kpc) of the binary star system from the centre of the main galaxy is not unusual for stars in the host galaxy or stars originating in the merging galaxy, and therefore any constraints on the kick velocity imparted to the progenitor are poor.

  5. A dynamic counterpart of Lamb vector in viscous compressible aerodynamics

    International Nuclear Information System (INIS)

    Liu, L Q; Wu, J Z; Shi, Y P; Zhu, J Y

    2014-01-01

    The Lamb vector is known to play a key role in incompressible fluid dynamics and vortex dynamics. In particular, in low-speed steady aerodynamics it is solely responsible for the total force acting on a moving body, known as the vortex force, with the classic two-dimensional (exact) Kutta–Joukowski theorem and three-dimensional (linearized) lifting-line theory as the most famous special applications. In this paper we identify an innovative dynamic counterpart of the Lamb vector in viscous compressible aerodynamics, which we call the compressible Lamb vector. Mathematically, we present a theorem on the dynamic far-field decay law of the vorticity and dilatation fields, and thereby prove that the generalized Lamb vector enjoys exactly the same integral properties as the Lamb vector does in incompressible flow, and hence the vortex-force theory can be generalized to compressible flow with exactly the same general formulation. Moreover, for steady flow of polytropic gas, we show that physically the force exerted on a moving body by the gas consists of a transverse force produced by the original Lamb vector and a new longitudinal force that reflects the effects of compression and irreversible thermodynamics. (paper)

  6. The Hunt for a Counterpart to GW150914

    Science.gov (United States)

    Kohler, Susanna

    2016-07-01

    On 14 September 2015, the Laser Interferometer Gravitational-wave Observatory (LIGO) in a pre-operative testing state at the time detected its first sign of gravitational-waves. The LIGO team sprang into action, performing data-quality checks on this unexpected signal. Within two days, they had sent a notification to 63 observing teams at observatories representing the entire electromagnetic spectrum, from radio to gamma-ray wavelengths.Illustration of a binary neutron star merger. The neutron stars 1) inspiral, 2) can produce a short gamma-ray burst, 3) can fling out hot, radioactive material in the form of a kilonova, and 4) form a massive neutron star or black hole with a possible remnant debris disk around it. [NASA/ESA/A. Feild (STScI)]Thus began the very first hunt for an electromagnetic counterpart to a detected gravitational wave signal.What were they looking for?As two compact objects in a binary system merge, the system is expected to emit energy in the form of gravitational waves. If both of the compact objects are black holes, were unlikely to see any electromagnetic radiation in the process, unless the merger is occurring in an (improbable) environment filled with gas and dust.But if one or both of the two compact objects is a neutron star, then there are a number of electromagnetic signatures that could occur due to energetic outflows. If a relativistic jet forms, we could see a short gamma-ray burst and X-ray, optical, and radio afterglows. Sub-relativistic outflows could produce optical and near-infrared signals, or a radio blast wave.Timeline of observations of GW150914, separated by wavelength band, and relative to the time of the gravitational-wave trigger. The top row shows LIGO information releases. The bottom four rows show high-energy, optical, near-infrared, and radio observations, respectively. Click for a closer look! [Abbott et al. 2016]Surprise SignalSince LIGO and Virgo (LIGOs European counterpart), wereprimarily expecting to detect

  7. ELECTROMAGNETIC COUNTERPARTS TO BLACK HOLE MERGERS DETECTED BY LIGO

    Energy Technology Data Exchange (ETDEWEB)

    Loeb, Abraham, E-mail: aloeb@cfa.harvard.edu [Department of Astronomy, Harvard University, 60 Garden St., Cambridge, MA 02138 (United States)

    2016-03-10

    Mergers of stellar-mass black holes (BHs), such as GW150914 observed by Laser Interferometer Gravitational Wave Observatory (LIGO), are not expected to have electromagnetic counterparts. However, the Fermi GBM detector identified a γ-ray transient 0.4 s after the gravitational wave (GW) signal GW150914 with consistent sky localization. I show that the two signals might be related if the BH binary detected by LIGO originated from two clumps in a dumbbell configuration that formed when the core of a rapidly rotating massive star collapsed. In that case, the BH binary merger was followed by a γ-ray burst (GRB) from a jet that originated in the accretion flow around the remnant BH. A future detection of a GRB afterglow could be used to determine the redshift and precise localization of the source. A population of standard GW sirens with GRB redshifts would provide a new approach for precise measurements of cosmological distances as a function of redshift.

  8. Unidentified EGRET sources and their possible Fermi counterparts

    International Nuclear Information System (INIS)

    Lyapin, A R; Arkhangelskaja, I V; Larin, D S

    2017-01-01

    Unidentified EGRET sources from 3EG catalog have been analyzed. Preliminary data analysis has shown at least 23 of these sources coincide with those in 3FGL Fermi catalogue within 1, 2 and 3 sigma error intervals of the coordinates and fluxes. Their properties are discussed in the presented work. Even 3-sigma difference allows supposing sources similarity because of more than 3-sigma distinctions in values of fluxes between identified EGRET sources and their Fermi counterparts. For instance, the coincidence between 3EG J1255-0549 and 3FGL J1256.1-0547 was reported in Fermi catalogues 1FGL, 2FGL, 3FGL. However, these sources fluxes (in units of 10 −8 photons × cm −2 × s −1 ) in the energy band E > 100 MeV were 179.7 ± 6.7 (3EG), 44.711 ± 0.724 (3FGL), 53.611 ± 0.997 (2FGL) and 67.939 ± 1.861 (1FGL). Such effect was observed for sufficient portion of identified EGRET sources. It could cause by troubles of particles identification by Fermi/LAT trigger system. Very often charged particles recognized as gamma-quanta because of wrong backsplash analysis. Nevertheless, gammas counts as charged particles due analogous reason and rejected during ground data processing. For example, it appears as geomagnetic modulation presence on gamma-quanta count rate latitudinal profiles in energy band E > 20 MeV. (paper)

  9. X-ray counterpart candidates for six new γ-ray pulsars

    Science.gov (United States)

    Zyuzin, Dmitry A.; Karpova, Anna V.; Shibanov, Yuriy A.

    2018-05-01

    Using archival X-ray data, we have found point-like X-ray counterpart candidates positionally coincident with six γ-ray pulsars discovered recently in the Fermi Gamma-ray Space Telescope data by the Einstein@Home project. The candidates for PSRs J0002+6216, J0554+3107, J1844-0346, and J1105-6037 are detected with Swift, and those for PSRs J0359+5414 and J2017+3625 are detected with Chandra. Despite a low count statistics for some candidates, assuming plausible constraints on the absorbing column density towards the pulsars, we show that X-ray spectral properties for all of them are consistent with those observed for other pulsars. J0359+5414 is the most reliably identified object. We detect a nebula around it, whose spectrum and extent suggest that this is a pulsar wind nebula powered by the pulsar. Associations of J0002+6216 and J1844-0346 with supernova remnants CTB 1 and G28.6-0.1 are proposed.

  10. Spectral Decomposition Algorithm (SDA)

    Data.gov (United States)

    National Aeronautics and Space Administration — Spectral Decomposition Algorithm (SDA) is an unsupervised feature extraction technique similar to PCA that was developed to better distinguish spectral features in...

  11. Spectral Imaging by Upconversion

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin; Pedersen, Christian; Tidemand-Lichtenberg, Peter

    2011-01-01

    We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard sili...... silicon based cameras designed for visible/near infrared radiation to be used for spectral images in the mid infrared. This can lead to much lower costs for such imaging devices, and a better performance.......We present a method to obtain spectrally resolved images using upconversion. By this method an image is spectrally shifted from one spectral region to another wavelength. Since the process is spectrally sensitive it allows for a tailored spectral response. We believe this will allow standard...

  12. TOWARD UNDERSTANDING THE B[e] PHENOMENON. III. PROPERTIES OF THE OPTICAL COUNTERPART OF IRAS 00470+6429

    International Nuclear Information System (INIS)

    Miroshnichenko, A. S.; Chentsov, E. L.; Klochkova, V. G.; Zharikov, S. V.; Grankin, K. N.; Kusakin, A. V.; Gandet, T. L.; Klingenberg, G.; Kildahl, S.; Rudy, R. J.; Lynch, D. K.; Venturini, C. C.; Mazuk, S.; Puetter, R. C.; Perry, R. B.; Carciofi, A. C.; Bjorkman, K. S.; Gray, R. O.; Bernabei, S.; Polcaro, V. F.

    2009-01-01

    FS CMa type stars are a group of Galactic objects with the B[e] phenomenon. They exhibit strong emission-line spectra and infrared excesses, which are most likely due to recently formed circumstellar dust. The group content and identification criteria were described in the first two papers of the series. In this paper we report our spectroscopic and photometric observations of the optical counterpart of IRAS 00470+6429 obtained in 2003-2008. The optical spectrum is dominated by emission lines, most of which have P Cyg type profiles. We detected significant brightness variations, which may include a regular component, and variable spectral line profiles in both shape and position. The presence of a weak Li I 6708 A line in the spectrum suggests that the object is most likely a binary system with a B2-B3 spectral-type primary companion of a luminosity log L/L sun = 3.9 ± 0.3 and a late-type secondary companion. We estimate a distance toward the object to be 2.0 ± 0.3 kpc from the Sun.

  13. VizieR Online Data Catalog: Selecting IRAC counterparts to SMGs (Alberts+, 2013)

    Science.gov (United States)

    Alberts, S.; Wilson, G. W.; Lu, Y.; Johnson, S.; Yun, M. S.; Scott, K. S.; Pope, A.; Aretxaga, I.; Ezawa, H.; Hughes, D. H.; Kawabe, R.; Kim, S.; Kohno, K.; Oshima, T.

    2014-05-01

    We present a new submm/mm galaxy counterpart identification technique which builds on the use of Spitzer Infrared Array Camera (IRAC) colours as discriminators between likely counterparts and the general IRAC galaxy population. Using 102 radio- and Submillimeter Array-confirmed counterparts to AzTEC sources across three fields [Great Observatories Origins Deep Survey-North, -South and Cosmic Evolution Survey (COSMOS)], we develop a non-parametric IRAC colour-colour characteristic density distribution, which, when combined with positional uncertainty information via likelihood ratios, allows us to rank all potential IRAC counterparts around submillimetre galaxies (SMGs) and calculate the significance of each ranking via the reliability factor. We report all robust and tentative radio counterparts to SMGs, the first such list available for AzTEC/COSMOS, as well as the highest ranked IRAC counterparts for all AzTEC SMGs in these fields as determined by our technique. We demonstrate that the technique is free of radio bias and thus applicable regardless of radio detections. For observations made with a moderate beam size (~18"), this technique identifies ~85% of SMG counterparts. For much larger beam sizes (>~30"), we report identification rates of 33-49%. Using simulations, we demonstrate that this technique is an improvement over using positional information alone for observations with facilities such as AzTEC on the Large Millimeter Telescope and Submillimeter Common User Bolometer Array 2 on the James Clerk Maxwell Telescope. (3 data files).

  14. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. I. Discovery of the Optical Counterpart Using the Dark Energy Camera

    Science.gov (United States)

    Soares-Santos, M.; Holz, D. E.; Annis, J.; Chornock, R.; Herner, K.; Berger, E.; Brout, D.; Chen, H.-Y.; Kessler, R.; Sako, M.; Allam, S.; Tucker, D. L.; Butler, R. E.; Palmese, A.; Doctor, Z.; Diehl, H. T.; Frieman, J.; Yanny, B.; Lin, H.; Scolnic, D.; Cowperthwaite, P.; Neilsen, E.; Marriner, J.; Kuropatkin, N.; Hartley, W. G.; Paz-Chinchón, F.; Alexander, K. D.; Balbinot, E.; Blanchard, P.; Brown, D. A.; Carlin, J. L.; Conselice, C.; Cook, E. R.; Drlica-Wagner, A.; Drout, M. R.; Durret, F.; Eftekhari, T.; Farr, B.; Finley, D. A.; Foley, R. J.; Fong, W.; Fryer, C. L.; García-Bellido, J.; Gill, M. S. S.; Gruendl, R. A.; Hanna, C.; Kasen, D.; Li, T. S.; Lopes, P. A. A.; Lourenço, A. C. C.; Margutti, R.; Marshall, J. L.; Matheson, T.; Medina, G. E.; Metzger, B. D.; Muñoz, R. R.; Muir, J.; Nicholl, M.; Quataert, E.; Rest, A.; Sauseda, M.; Schlegel, D. J.; Secco, L. F.; Sobreira, F.; Stebbins, A.; Villar, V. A.; Vivas, K.; Walker, A. R.; Wester, W.; Williams, P. K. G.; Zenteno, A.; Zhang, Y.; Abbott, T. M. C.; Abdalla, F. B.; Banerji, M.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Brooks, D.; Buckley-Geer, E.; Burke, D. L.; Carnero Rosell, A.; Carrasco Kind, M.; Carretero, J.; Castander, F. J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; Desai, S.; Dietrich, J. P.; Doel, P.; Eifler, T. F.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gaztanaga, E.; Gerdes, D. W.; Giannantonio, T.; Goldstein, D. A.; Gruen, D.; Gschwend, J.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Kent, S.; Krause, E.; Kron, R.; Kuehn, K.; Kuhlmann, S.; Lahav, O.; Lima, M.; Maia, M. A. G.; March, M.; McMahon, R. G.; Menanteau, F.; Miquel, R.; Mohr, J. J.; Nichol, R. C.; Nord, B.; Ogando, R. L. C.; Petravick, D.; Plazas, A. A.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Thomas, R. C.; Troxel, M. A.; Vikram, V.; Wechsler, R. H.; Weller, J.; Dark Energy Survey; Dark Energy Camera GW-EM Collaboration

    2017-10-01

    We present the Dark Energy Camera (DECam) discovery of the optical counterpart of the first binary neutron star merger detected through gravitational-wave emission, GW170817. Our observations commenced 10.5 hr post-merger, as soon as the localization region became accessible from Chile. We imaged 70 deg2 in the I and z bands, covering 93% of the initial integrated localization probability, to a depth necessary to identify likely optical counterparts (e.g., a kilonova). At 11.4 hr post-merger we detected a bright optical transient located 10\\buildrel{\\prime\\prime}\\over{.} 6 from the nucleus of NGC 4993 at redshift z = 0.0098, consistent (for {H}0=70 km s-1 Mpc-1) with the distance of 40 ± 8 Mpc reported by the LIGO Scientific Collaboration and the Virgo Collaboration (LVC). At detection the transient had magnitudes of I=17.3 and z=17.4, and thus an absolute magnitude of {M}I=-15.7, in the luminosity range expected for a kilonova. We identified 1500 potential transient candidates. Applying simple selection criteria aimed at rejecting background events such as supernovae, we find the transient associated with NGC 4993 as the only remaining plausible counterpart, and reject chance coincidence at the 99.5% confidence level. We therefore conclude that the optical counterpart we have identified near NGC 4993 is associated with GW170817. This discovery ushers in the era of multi-messenger astronomy with gravitational waves and demonstrates the power of DECam to identify the optical counterparts of gravitational-wave sources.

  15. Search for Electromagnetic Counterparts to LIGO-Virgo Candidates: Expanded Very Large Array Observations

    Science.gov (United States)

    Lazio, Joseph; Keating, Katie; Jenet, F. A.; Kassim, N. E.

    2011-01-01

    This paper summarizes a search for radio wavelength counterparts to candidate gravitational wave events. The identification of an electromagnetic counterpart could provide a more complete understanding of a gravitational wave event, including such characteristics as the location and the nature of the progenitor. We used the Expanded Very Large Array (EVLA) to search six galaxies which were identified as potential hosts for two candidate gravitational wave events. We summarize our procedures and discuss preliminary results.

  16. An Instructor’s Guide for the Building and Sustaining Foreign Counterpart Organizations Curriculum

    Science.gov (United States)

    2016-02-01

    Collectivist values and perspectives may differ from ours, thus advisors should take time to understand the viewpoint( s) of counterparts. • A counterpart-led...2003). Levels of organizational trust in individualist versus collectivist societies: A seven-nation study. Organizational Science, 14, 81-90. Keller...strategies that work in collectivist cultures where U.S. military advisors and other senior U.S. government leaders are likely to be assigned. Based on the

  17. Adaptive Spectral Doppler Estimation

    DEFF Research Database (Denmark)

    Gran, Fredrik; Jakobsson, Andreas; Jensen, Jørgen Arendt

    2009-01-01

    . The methods can also provide better quality of the estimated power spectral density (PSD) of the blood signal. Adaptive spectral estimation techniques are known to pro- vide good spectral resolution and contrast even when the ob- servation window is very short. The 2 adaptive techniques are tested......In this paper, 2 adaptive spectral estimation techniques are analyzed for spectral Doppler ultrasound. The purpose is to minimize the observation window needed to estimate the spectrogram to provide a better temporal resolution and gain more flexibility when designing the data acquisition sequence...... and compared with the averaged periodogram (Welch’s method). The blood power spectral capon (BPC) method is based on a standard minimum variance technique adapted to account for both averaging over slow-time and depth. The blood amplitude and phase estimation technique (BAPES) is based on finding a set...

  18. Massive scalar counterpart of gravitational waves in scalarized neutron star binaries

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Jing [Sun Yat-sen University, School of Physics and Astronomy, Guangzhou (China)

    2017-09-15

    In analogy with spontaneous magnetization of ferromagnets below the Curie temperature, a neutron star (NS), with a compactness above a certain critical value, may undergo spontaneous scalarization and exhibit an interior nontrivial scalar configuration. Consequently, the exterior spacetime is changed, and an external scalar field appears, which subsequently triggers a scalarization of its companion. The dynamical interplay produces a gravitational scalar counterpart of tensor gravitational waves. In this paper, we resort to scalar-tensor theory and demonstrate that the gravitational scalar counterpart from a double neutron star (DNS) and a neutron star-white dwarf (NS-WD) system become massive. We report that (1) a gravitational scalar background field, arising from convergence of external scalar fields, plays the role of gravitational scalar counterpart in scalarized DNS binary, and the appearance of a mass-dimensional constant in a Higgs-like gravitational scalar potential is responsible for a massive gravitational scalar counterpart with a mass of the order of the Planck scale; (2) a dipolar gravitational scalar radiated field, resulting from differing binding energies of NS and WD, plays the role of a gravitational scalar counterpart in scalarized orbital shrinking NS-WDs, which oscillates around a local and scalar-energy-density-dependent minimum of the gravitational scalar potential and obtains a mass of the order of about 10{sup -21} eV/c{sup 2}. (orig.)

  19. Observations of the First Electromagnetic Counterpart to a Gravitational-wave Source by the TOROS Collaboration

    Science.gov (United States)

    Díaz, M. C.; Macri, L. M.; Garcia Lambas, D.; Mendes de Oliveira, C.; Nilo Castellón, J. L.; Ribeiro, T.; Sánchez, B.; Schoenell, W.; Abramo, L. R.; Akras, S.; Alcaniz, J. S.; Artola, R.; Beroiz, M.; Bonoli, S.; Cabral, J.; Camuccio, R.; Castillo, M.; Chavushyan, V.; Coelho, P.; Colazo, C.; Costa-Duarte, M. V.; Cuevas Larenas, H.; DePoy, D. L.; Domínguez Romero, M.; Dultzin, D.; Fernández, D.; García, J.; Girardini, C.; Gonçalves, D. R.; Gonçalves, T. S.; Gurovich, S.; Jiménez-Teja, Y.; Kanaan, A.; Lares, M.; Lopes de Oliveira, R.; López-Cruz, O.; Marshall, J. L.; Melia, R.; Molino, A.; Padilla, N.; Peñuela, T.; Placco, V. M.; Quiñones, C.; Ramírez Rivera, A.; Renzi, V.; Riguccini, L.; Ríos-López, E.; Rodriguez, H.; Sampedro, L.; Schneiter, M.; Sodré, L.; Starck, M.; Torres-Flores, S.; Tornatore, M.; Zadrożny, A.

    2017-10-01

    We present the results of prompt optical follow-up of the electromagnetic counterpart of the gravitational-wave event GW170817 by the Transient Optical Robotic Observatory of the South Collaboration. We detected highly significant dimming in the light curves of the counterpart ({{Δ }}g=0.17+/- 0.03 mag, {{Δ }}r=0.14+/- 0.02 mag, {{Δ }}I=0.10+/- 0.03 mag) over the course of only 80 minutes of observations obtained ˜35 hr after the trigger with the T80-South telescope. A second epoch of observations, obtained ˜59 hr after the event with the EABA 1.5 m telescope, confirms the fast fading nature of the transient. The observed colors of the counterpart suggest that this event was a “blue kilonova” relatively free of lanthanides.

  20. Chronic Lymphocytic Leukemia B-Cell Normal Cellular Counterpart: Clues From a Functional Perspective.

    Science.gov (United States)

    Darwiche, Walaa; Gubler, Brigitte; Marolleau, Jean-Pierre; Ghamlouch, Hussein

    2018-01-01

    Chronic lymphocytic leukemia (CLL) is characterized by the clonal expansion of small mature-looking CD19+ CD23+ CD5+ B-cells that accumulate in the blood, bone marrow, and lymphoid organs. To date, no consensus has been reached concerning the normal cellular counterpart of CLL B-cells and several B-cell types have been proposed. CLL B-cells have remarkable phenotypic and gene expression profile homogeneity. In recent years, the molecular and cellular biology of CLL has been enriched by seminal insights that are leading to a better understanding of the natural history of the disease. Immunophenotypic and molecular approaches (including immunoglobulin heavy-chain variable gene mutational status, transcriptional and epigenetic profiling) comparing the normal B-cell subset and CLL B-cells provide some new insights into the normal cellular counterpart. Functional characteristics (including activation requirements and propensity for plasma cell differentiation) of CLL B-cells have now been investigated for 50 years. B-cell subsets differ substantially in terms of their functional features. Analysis of shared functional characteristics may reveal similarities between normal B-cell subsets and CLL B-cells, allowing speculative assignment of a normal cellular counterpart for CLL B-cells. In this review, we summarize current data regarding peripheral B-cell differentiation and human B-cell subsets and suggest possibilities for a normal cellular counterpart based on the functional characteristics of CLL B-cells. However, a definitive normal cellular counterpart cannot be attributed on the basis of the available data. We discuss the functional characteristics required for a cell to be logically considered to be the normal counterpart of CLL B-cells.

  1. Precise localizations and counterpart searches of GRBs from the 2nd interplanetary network

    International Nuclear Information System (INIS)

    Hack, F.; Hurley, K.; Atteia, J.; Barat, C.; Niel, M.; Cline, T.; Dennis, B.; Kouveliotou, C.; Klebesadel, R.; Laros, J.; Kurt, V.; Kuznetsov, A.; Zenchenko, V.

    1994-01-01

    The second interplanetary network of GRB detectors operated between 1981 and 1984. It consisted of the Venera 13 and V14 spacecraft (SIGNE detectors), PVO, ICE, and SMM (HXRBS detector). Many of the approximately 90 cosmic GRBs it detected can be localized to a high accuracy. Such localizations will make a better estimate of the burster recurrence time possible and contribute to the search for quiescent counterparts. We will present a number of localizations to illustrate the potential of this network, discuss the techniques we use to perform multi-wavelength counterpart searches, and compare present and promising future localization techniques

  2. Discovery of the optical counterpart and early optical observations of GRB 990712

    DEFF Research Database (Denmark)

    Sahu, K.C.; Vreesvijk, P.; Bakos, G.

    2000-01-01

    We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands during the first similar to 35 days after the outburst. The observed light curves were fitted with a po......We present the discovery observations of the optical counterpart of the gamma-ray burst GRB 990712 taken 4.16 hr after the outburst and discuss its light curve observed in the V, R, and I bands during the first similar to 35 days after the outburst. The observed light curves were fitted...

  3. Spectral radius of graphs

    CERN Document Server

    Stevanovic, Dragan

    2015-01-01

    Spectral Radius of Graphs provides a thorough overview of important results on the spectral radius of adjacency matrix of graphs that have appeared in the literature in the preceding ten years, most of them with proofs, and including some previously unpublished results of the author. The primer begins with a brief classical review, in order to provide the reader with a foundation for the subsequent chapters. Topics covered include spectral decomposition, the Perron-Frobenius theorem, the Rayleigh quotient, the Weyl inequalities, and the Interlacing theorem. From this introduction, the

  4. Counterpart experimental study of ISP-42 PANDA tests on PUMA facility

    International Nuclear Information System (INIS)

    Yang, Jun; Choi, Sung-Won; Lim, Jaehyok; Lee, Doo-Yong; Rassame, Somboon; Hibiki, Takashi; Ishii, Mamoru

    2013-01-01

    Highlights: ► Counterpart tests were performed on two large-scale BWR integral facilities. ► Similarity of post-LOCA system behaviors observed between two tests. ► Passive core and containment cooling systems work as design in both tests. -- Abstract: A counterpart test to the Passive Nachwärmeabfuhr und Druckabbau Test Anlage (Passive Decay Heat Removal and Depressurization Test Facility, PANDA) International Standard Problem (ISP)-42 test was conducted at the Purdue University Multi-Dimensional Integral Test Assembly (PUMA) facility. Aimed to support code validation on a range of light water reactor (LWR) containment issues, the ISP-42 test consists of six sequential phases (Phases A–F) with separately defined initial and boundary conditions, addressing different stages of anticipated accident scenario and system responses. The counterpart test was performed from Phases A to D, which are within the scope of the normal integral tests performed on the PUMA facility. A scaling methodology was developed by using the PANDA facility as prototype and PUMA facility as test model, and an engineering scaling has been applied to the PUMA facility. The counterpart test results indicated that functions of passive safety systems, such as passive containment cooling system (PCCS) start-up, gravity-driven cooling system (GDCS) discharge, PCCS normal operation and overload function were confirmed in both the PANDA and PUMA facilities with qualitative similarities

  5. Unmixing of spectrally similar minerals

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available techniques is complicated when considering very similar spectral signatures. Iron-bearing oxide/hydroxide/sulfate minerals have similar spectral signatures. The study focuses on how could estimates of abundances of spectrally similar iron-bearing oxide...

  6. Vowel Inherent Spectral Change

    CERN Document Server

    Assmann, Peter

    2013-01-01

    It has been traditional in phonetic research to characterize monophthongs using a set of static formant frequencies, i.e., formant frequencies taken from a single time-point in the vowel or averaged over the time-course of the vowel. However, over the last twenty years a growing body of research has demonstrated that, at least for a number of dialects of North American English, vowels which are traditionally described as monophthongs often have substantial spectral change. Vowel Inherent Spectral Change has been observed in speakers’ productions, and has also been found to have a substantial effect on listeners’ perception. In terms of acoustics, the traditional categorical distinction between monophthongs and diphthongs can be replaced by a gradient description of dynamic spectral patterns. This book includes chapters addressing various aspects of vowel inherent spectral change (VISC), including theoretical and experimental studies of the perceptually relevant aspects of VISC, the relationship between ar...

  7. High Resolution Spectral Analysis

    Science.gov (United States)

    2006-10-25

    liable methods for high resolution spectral analysis of multivariable processes, as well as to distance measures for quantitative assessment of...called "modern nonlinear spectral analysis methods " [27]. An alternative way to reconstruct /„(#), based on Tn, is the periodogram/correlogram f{6...eie). A homotopy method was proposed in [8, 9] leading to a differential equation for A(T) in a homotopy variable r. If the statistics are consistent

  8. Spectrally selective glazings

    Energy Technology Data Exchange (ETDEWEB)

    NONE

    1998-08-01

    Spectrally selective glazing is window glass that permits some portions of the solar spectrum to enter a building while blocking others. This high-performance glazing admits as much daylight as possible while preventing transmission of as much solar heat as possible. By controlling solar heat gains in summer, preventing loss of interior heat in winter, and allowing occupants to reduce electric lighting use by making maximum use of daylight, spectrally selective glazing significantly reduces building energy consumption and peak demand. Because new spectrally selective glazings can have a virtually clear appearance, they admit more daylight and permit much brighter, more open views to the outside while still providing the solar control of the dark, reflective energy-efficient glass of the past. This Federal Technology Alert provides detailed information and procedures for Federal energy managers to consider spectrally selective glazings. The principle of spectrally selective glazings is explained. Benefits related to energy efficiency and other architectural criteria are delineated. Guidelines are provided for appropriate application of spectrally selective glazing, and step-by-step instructions are given for estimating energy savings. Case studies are also presented to illustrate actual costs and energy savings. Current manufacturers, technology users, and references for further reading are included for users who have questions not fully addressed here.

  9. IDENTIFYING ELUSIVE ELECTROMAGNETIC COUNTERPARTS TO GRAVITATIONAL WAVE MERGERS: AN END-TO-END SIMULATION

    International Nuclear Information System (INIS)

    Nissanke, Samaya; Georgieva, Alexandra; Kasliwal, Mansi

    2013-01-01

    Combined gravitational wave (GW) and electromagnetic (EM) observations of compact binary mergers should enable detailed studies of astrophysical processes in the strong-field gravity regime. This decade, ground-based GW interferometers promise to routinely detect compact binary mergers. Unfortunately, networks of GW interferometers have poor angular resolution on the sky and their EM signatures are predicted to be faint. Therefore, a challenging goal will be to unambiguously pinpoint the EM counterparts of GW mergers. We perform the first comprehensive end-to-end simulation that focuses on: (1) GW sky localization, distance measures, and volume errors with two compact binary populations and four different GW networks; (2) subsequent EM detectability by a slew of multiwavelength telescopes; and (3) final identification of the merger counterpart amidst a sea of possible astrophysical false positives. First, we find that double neutron star binary mergers can be detected out to a maximum distance of 400 Mpc (or 750 Mpc) by three (or five) detector GW networks, respectively. Neutron-star-black-hole binary mergers can be detected a factor of 1.5 further out; their median to maximum sky localizations are 50-170 deg 2 (or 6-65 deg 2 ) for a three (or five) detector GW network. Second, by optimizing depth, cadence, and sky area, we quantify relative fractions of optical counterparts that are detectable by a suite of different aperture-size telescopes across the globe. Third, we present five case studies to illustrate the diversity of scenarios in secure identification of the EM counterpart. We discuss the case of a typical binary, neither beamed nor nearby, and the challenges associated with identifying an EM counterpart at both low and high Galactic latitudes. For the first time, we demonstrate how construction of low-latency GW volumes in conjunction with local universe galaxy catalogs can help solve the problem of false positives. We conclude with strategies that would

  10. Discovery, Follow-up, and Implications of the Optical/Infrared Counterpart to GW170817

    Science.gov (United States)

    Drout, Maria

    2018-01-01

    On August 17th, 2017, the field of multi-messenger, gravitational-wave, astronomy was born. On this date, Advanced LIGO and Advanced Virgo observed gravitational waves from the coalescence of a neutron star binary with a false alarm probability of 1 per 10000 years and electromagnetic counterparts were subsequently identified across the entire electromagnetic spectrum. In this talk, I will give a broad review of the optical and infrared emission associated with the binary neutron star merger, GW170817. I will describe the process of the discovery and localization of the optical counterpart, and review the extensive follow-up observations obtained over the following three weeks. Finally, I will place these results in context. I will discuss the implications of these observations on our understanding of the ejecta from neutron star mergers, the origin of r-process elements, and the prospects for the identification of similar transients in upcoming surveys.

  11. The prompt acquisition of gamma ray optical counterparts with the Bradford Robotic Telescope

    Science.gov (United States)

    Baruch, J. E. F.; Bennett, C.; Cox, M. J.; Davis, R.

    1996-08-01

    The Bradford Robotic Telescope was conceived as an instrument to work with observers in other wavebands and specifically to monitor gamma sources and acquire optical counterparts to gamma-bursters. Its main line of support has been to provide an automated robotic photometry service on the Internet. Its first light was in the autumn of 1993. The telescope and its development are described (http://www.telescope.org/rti). The development of instrumentation for astronomy in an engineering department is discussed and the evolution of the networking and communications is described to the point where a fast link to the Internet BACODINE system can be achieved. The current performance is detailed with estimates of its efficiency. Images of BATSE error boxes are discussed. Current plans are to better match the field of the telescope to the BATSE error boxes and to monitor optical counterparts on a fractional second time scale.

  12. HST/ACS Imaging of Omega Centauri: Optical Counterparts of Chandra X-Ray Sources

    Science.gov (United States)

    Cool, Adrienne M.; Haggard, Daryl; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Anderson, Jay

    2013-02-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ~10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ~40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  13. Finding X-ray counterparts for unidentified sources in the 105 months BAT survey - 1

    Science.gov (United States)

    Stephen, J. B.; Bassani, L.; Malizia, A.; Masetti, N.; Ubertini, P.

    2018-02-01

    We provide X-ray counterparts for the unidentified Swift/BAT sources listed in the 105 month catalogue (Oh et al. 2018, ApJS in press). These associations were found by cross-correlating the list of U1,U2 and U3 sources with the ROSAT Bright (RASSBSC, Voges et al. 1999, A & A, 349, 389) and the XMM-Newton Slew (XMMSlew, Saxton et al. 2008, A & A, 480, 611) catalogues.

  14. Finding X-ray counterparts for unidentified sources in the 105 months BAT survey - 2

    Science.gov (United States)

    Stephen, J. B.; Bassani, L.; Malizia, A.; Masetti, N.; Ubertini, P.

    2018-02-01

    We provide X-ray counterparts for unidentified Swift/BAT sources in the 105 month catalogue (Oh et al. 2018, ApJS in press). They were found by cross-correlating the list of U1,U2 and U3 sources with the ROSAT Bright (RASSBSC, Voges et al. 1999, A & A, 349, 389) and XMM-Newton Slew (XMMSlew, Saxton et al. 2008, A & A, 480, 611) catalogues and optically identified as reported in Atel #11340.

  15. Strategic Wholesale Pricing for an Incumbent Supplier Facing with a Competitive Counterpart

    OpenAIRE

    Sun, Jianwu

    2014-01-01

    We introduce a wholesale pricing strategy for an incumbent supplier facing with a competitive counterpart. We propose a profit function which considers both the present loss and future loss from a wholesale price and then study the optimal wholesale prices for different objectives about this profit function for the incumbent supplier. First, we achieve an optimal wholesale price for the incumbent supplier to maximize his expected profit. Then, to reduce the risk originating from the fluctuati...

  16. Counterpart synchronization of duplex networks with delayed nodes and noise perturbation

    International Nuclear Information System (INIS)

    Wei, Xiang; Wu, Xiaoqun; Lu, Jun-an; Zhao, Junchan

    2015-01-01

    In the real world, many complex systems are represented not by single networks but rather by sets of interdependent ones. In these specific networks, nodes in one network mutually interact with nodes in other networks. This paper focuses on a simple representative case of two-layer networks (the so-called duplex networks) with unidirectional inter-layer couplings. That is, each node in one network depends on a counterpart in the other network. Accordingly, the former network is called the response layer and the latter network is the drive layer. Specifically, synchronization between each node in the drive layer and its counterpart in the response layer (counterpart synchronization (CS)) in these kinds of duplex networks with delayed nodes and noise perturbation is investigated. Based on the LaSalle-type invariance principle, a control technique is proposed and a sufficient condition is developed for realizing CS of duplex networks. Furthermore, two corollaries are derived as special cases. In addition, node dynamics within each layer can be varied and topologies of the two layers are not necessarily identical. Therefore, the proposed synchronization method can be applied to a wide range of multiplex networks. Numerical examples are provided to illustrate the feasibility and effectiveness of the results. (paper)

  17. CRISS power spectral density

    International Nuclear Information System (INIS)

    Vaeth, W.

    1979-04-01

    The correlation of signal components at different frequencies like higher harmonics cannot be detected by a normal power spectral density measurement, since this technique correlates only components at the same frequency. This paper describes a special method for measuring the correlation of two signal components at different frequencies: the CRISS power spectral density. From this new function in frequency analysis, the correlation of two components can be determined quantitatively either they stem from one signal or from two diverse signals. The principle of the method, suitable for the higher harmonics of a signal as well as for any other frequency combinations is shown for the digital frequency analysis technique. Two examples of CRISS power spectral densities demonstrates the operation of the new method. (orig.) [de

  18. Parametric Explosion Spectral Model

    Energy Technology Data Exchange (ETDEWEB)

    Ford, S R; Walter, W R

    2012-01-19

    Small underground nuclear explosions need to be confidently detected, identified, and characterized in regions of the world where they have never before occurred. We develop a parametric model of the nuclear explosion seismic source spectrum derived from regional phases that is compatible with earthquake-based geometrical spreading and attenuation. Earthquake spectra are fit with a generalized version of the Brune spectrum, which is a three-parameter model that describes the long-period level, corner-frequency, and spectral slope at high-frequencies. Explosion spectra can be fit with similar spectral models whose parameters are then correlated with near-source geology and containment conditions. We observe a correlation of high gas-porosity (low-strength) with increased spectral slope. The relationship between the parametric equations and the geologic and containment conditions will assist in our physical understanding of the nuclear explosion source.

  19. Spectral analysis by correlation

    International Nuclear Information System (INIS)

    Fauque, J.M.; Berthier, D.; Max, J.; Bonnet, G.

    1969-01-01

    The spectral density of a signal, which represents its power distribution along the frequency axis, is a function which is of great importance, finding many uses in all fields concerned with the processing of the signal (process identification, vibrational analysis, etc...). Amongst all the possible methods for calculating this function, the correlation method (correlation function calculation + Fourier transformation) is the most promising, mainly because of its simplicity and of the results it yields. The study carried out here will lead to the construction of an apparatus which, coupled with a correlator, will constitute a set of equipment for spectral analysis in real time covering the frequency range 0 to 5 MHz. (author) [fr

  20. Plasmonic spectral tunability of conductive ternary nitrides

    Energy Technology Data Exchange (ETDEWEB)

    Kassavetis, S.; Patsalas, P., E-mail: ppats@physics.auth.gr [Department of Physics, Aristotle University of Thessaloniki, GR-54124 Thessaloniki (Greece); Bellas, D. V.; Lidorikis, E. [Department of Materials Science and Engineering, University of Ioannina, GR-45110 Ioannina (Greece); Abadias, G. [Institut Pprime, Département Physique et Mécanique des Matériaux, Université de Poitiers-CNRS-ENSMA, 86962 Chasseneuil-Futuroscope (France)

    2016-06-27

    Conductive binary transition metal nitrides, such as TiN and ZrN, have emerged as a category of promising alternative plasmonic materials. In this work, we show that ternary transition metal nitrides such as Ti{sub x}Ta{sub 1−x}N, Ti{sub x}Zr{sub 1−x}N, Ti{sub x}Al{sub 1−x}N, and Zr{sub x}Ta{sub 1−x}N share the important plasmonic features with their binary counterparts, while having the additional asset of the exceptional spectral tunability in the entire visible (400–700 nm) and UVA (315–400 nm) spectral ranges depending on their net valence electrons. In particular, we demonstrate that such ternary nitrides can exhibit maximum field enhancement factors comparable with gold in the aforementioned broadband range. We also critically evaluate the structural features that affect the quality factor of the plasmon resonance and we provide rules of thumb for the selection and growth of materials for nitride plasmonics.

  1. Spectral Ensemble Kalman Filters

    Czech Academy of Sciences Publication Activity Database

    Mandel, Jan; Kasanický, Ivan; Vejmelka, Martin; Fuglík, Viktor; Turčičová, Marie; Eben, Kryštof; Resler, Jaroslav; Juruš, Pavel

    2014-01-01

    Roč. 11, - (2014), EMS2014-446 [EMS Annual Meeting /14./ & European Conference on Applied Climatology (ECAC) /10./. 06.10.2014-10.10.2014, Prague] R&D Projects: GA ČR GA13-34856S Grant - others:NSF DMS -1216481 Institutional support: RVO:67985807 Keywords : data assimilation * spectral filter Subject RIV: DG - Athmosphere Sciences, Meteorology

  2. A Simple Spectral Observer

    Directory of Open Access Journals (Sweden)

    Lizeth Torres

    2018-05-01

    Full Text Available The principal aim of a spectral observer is twofold: the reconstruction of a signal of time via state estimation and the decomposition of such a signal into the frequencies that make it up. A spectral observer can be catalogued as an online algorithm for time-frequency analysis because is a method that can compute on the fly the Fourier transform (FT of a signal, without having the entire signal available from the start. In this regard, this paper presents a novel spectral observer with an adjustable constant gain for reconstructing a given signal by means of the recursive identification of the coefficients of a Fourier series. The reconstruction or estimation of a signal in the context of this work means to find the coefficients of a linear combination of sines a cosines that fits a signal such that it can be reproduced. The design procedure of the spectral observer is presented along with the following applications: (1 the reconstruction of a simple periodical signal, (2 the approximation of both a square and a triangular signal, (3 the edge detection in signals by using the Fourier coefficients, (4 the fitting of the historical Bitcoin market data from 1 December 2014 to 8 January 2018 and (5 the estimation of a input force acting upon a Duffing oscillator. To round out this paper, we present a detailed discussion about the results of the applications as well as a comparative analysis of the proposed spectral observer vis-à-vis the Short Time Fourier Transform (STFT, which is a well-known method for time-frequency analysis.

  3. Hunting Electromagnetic Counterparts of Gravitational-wave Events Using the Zwicky Transient Facility

    Science.gov (United States)

    Ghosh, Shaon; Chatterjee, Deep; Kaplan, David L.; Brady, Patrick R.; Van Sistine, Angela

    2017-11-01

    Detections of coalescing binary black holes by LIGO have opened a new window of transient astronomy. With increasing sensitivity of LIGO and participation of the Virgo detector in Cascina, Italy, we expect to soon detect coalescence of compact binary systems with one or more neutron stars. These are the prime targets for electromagnetic follow-up of gravitational wave triggers, which holds enormous promise of rich science. However, hunting for electromagnetic counterparts of gravitational wave events is a non-trivial task due to the sheer size of the error regions, which could span hundreds of square degrees. This may require deep observation with large field-of-view telescopes and/or use of galaxy catalogs. The Zwicky Transient facility (ZTF), scheduled to begin operation in 2017, is designed to cover such large sky-localization areas. In this work, we present the strategies of efficiently tiling the sky to facilitate the observation of the gravitational wave error regions using ZTF. To do this, we used simulations consisting of 475 binary neutron star coalescences detected using a mix of two- and three-detector networks. Our studies reveal that, using two overlapping sets of ZTF tiles and a (modified) ranked-tiling algorithm, we can cover the gravitational-wave sky-localization regions with half as many pointings as a simple contour-covering algorithm. We then incorporated the ranked-tiling strategy to study our ability to observe the counterparts. This requires optimization of observation depth and localization area coverage. Our results show that observation in r-band with ˜600 seconds of integration time per pointing seems to be optimum for typical assumed brightnesses of electromagnetic counterparts, if we plan to spend equal amount of time per pointing. However, our results also reveal that we can gain by as much as 50% in detection efficiency if we linearly scale our integration time per pointing based on the tile probability.

  4. DISCOVERY OF A TRANSIENT GAMMA-RAY COUNTERPART TO FRB 131104

    Energy Technology Data Exchange (ETDEWEB)

    DeLaunay, J. J.; Murase, K.; Mészáros, P.; Keivani, A.; Messick, C.; Mostafá, M. A.; Oikonomou, F.; Tešić, G.; Turley, C. F. [Department of Physics, Pennsylvania State University, University Park, PA 16802 (United States); Fox, D. B., E-mail: jjd330@psu.edu [Department of Astronomy and Astrophysics, Pennsylvania State University, University Park, PA 16802 (United States)

    2016-11-20

    We report our discovery in Swift satellite data of a transient gamma-ray counterpart (3.2 σ confidence) to the fast radio burst (FRB) FRB 131104, the first such counterpart to any FRB. The transient has a duration T {sub 90} ≳ 100 s and a fluence S{sub γ} ≈ 4 × 10{sup −6} erg cm{sup −2}, increasing the energy budget for this event by more than a billion times; at the nominal z ≈ 0.55 redshift implied by its dispersion measure, the burst’s gamma-ray energy output is E{sub γ} ≈ 5 × 10{sup 51} erg. The observed radio to gamma-ray fluence ratio for FRB 131104 is consistent with a lower limit we derive from Swift observations of another FRB, which is not detected in gamma-rays, and with an upper limit previously derived for the brightest gamma-ray flare from SGR 1806−20, which was not detected in the radio. X-ray, ultraviolet, and optical observations beginning two days after the FRB do not reveal any associated afterglow, supernova, or transient; Swift observations exclude association with the brightest 65% of Swift gamma-ray burst (GRB) X-ray afterglows, while leaving the possibility of an associated supernova at much more than 10% the FRB’s nominal distance, D ≳ 320 Mpc, largely unconstrained. Transient high-luminosity gamma-ray emission arises most naturally in a relativistic outflow or shock breakout, such as, for example, from magnetar flares, GRBs, relativistic supernovae, and some types of galactic nuclear activity. Our discovery thus bolsters the case for an extragalactic origin for some FRBs and suggests that future rapid-response observations might identify long-lived counterparts, resolving the nature of these mysterious phenomena and realizing their promise as probes of cosmology and fundamental physics.

  5. Energy metabolism in human pluripotent stem cells and their differentiated counterparts.

    Directory of Open Access Journals (Sweden)

    Sandra Varum

    Full Text Available Human pluripotent stem cells have the ability to generate all cell types present in the adult organism, therefore harboring great potential for the in vitro study of differentiation and for the development of cell-based therapies. Nonetheless their use may prove challenging as incomplete differentiation of these cells might lead to tumoregenicity. Interestingly, many cancer types have been reported to display metabolic modifications with features that might be similar to stem cells. Understanding the metabolic properties of human pluripotent stem cells when compared to their differentiated counterparts can thus be of crucial importance. Furthermore recent data has stressed distinct features of different human pluripotent cells lines, namely when comparing embryo-derived human embryonic stem cells (hESCs and induced pluripotent stem cells (IPSCs reprogrammed from somatic cells.We compared the energy metabolism of hESCs, IPSCs, and their somatic counterparts. Focusing on mitochondria, we tracked organelle localization and morphology. Furthermore we performed gene expression analysis of several pathways related to the glucose metabolism, including glycolysis, the pentose phosphate pathway and the tricarboxylic acid (TCA cycle. In addition we determined oxygen consumption rates (OCR using a metabolic extracellular flux analyzer, as well as total intracellular ATP levels by high performance liquid chromatography (HPLC. Finally we explored the expression of key proteins involved in the regulation of glucose metabolism.Our results demonstrate that, although the metabolic signature of IPSCs is not identical to that of hESCs, nonetheless they cluster with hESCs rather than with their somatic counterparts. ATP levels, lactate production and OCR revealed that human pluripotent cells rely mostly on glycolysis to meet their energy demands. Furthermore, our work points to some of the strategies which human pluripotent stem cells may use to maintain high

  6. A comparison between SALT/SAAO observations and kilonova models for AT 2017gfo: the first electromagnetic counterpart of a gravitational wave transient - GW170817

    Science.gov (United States)

    Buckley, David A. H.; Andreoni, Igor; Barway, Sudhanshu; Cooke, Jeff; Crawford, Steven M.; Gorbovskoy, Evgeny; Gromadzki, Mariusz; Lipunov, Vladimir; Mao, Jirong; Potter, Stephen B.; Pretorius, Magaretha L.; Pritchard, Tyler A.; Romero-Colmenero, Encarni; Shara, Michael M.; Väisänen, Petri; Williams, Ted B.

    2018-02-01

    We report on SALT low-resolution optical spectroscopy and optical/IR photometry undertaken with other SAAO telescopes (MASTER-SAAO and IRSF) of the kilonova AT 2017gfo (a.k.a. SSS17a) in the galaxy NGC4993 during the first 10 d of discovery. This event has been identified as the first ever electromagnetic counterpart of a gravitational wave event, namely GW170817, which was detected by the LIGO and Virgo gravitational wave observatories. The event is likely due to a merger of two neutron stars, resulting in a kilonova explosion. SALT was the third observatory to obtain spectroscopy of AT 2017gfo and the first spectrum, 1.2 d after the merger, is quite blue and shows some broad features, but no identifiable spectral lines and becomes redder by the second night. We compare the spectral and photometric evolution with recent kilonova simulations and conclude that they are in qualitative agreement for post-merger wind models with proton:nucleon ratios of Ye = 0.25-0.30. The blue colour of the first spectrum is consistent with the lower opacity of the lanthanide-free r-process elements in the ejecta. Differences between the models and observations are likely due to the choice of system parameters combined with the absence of atomic data for more elements in the ejecta models.

  7. Wavelength conversion based spectral imaging

    DEFF Research Database (Denmark)

    Dam, Jeppe Seidelin

    There has been a strong, application driven development of Si-based cameras and spectrometers for imaging and spectral analysis of light in the visible and near infrared spectral range. This has resulted in very efficient devices, with high quantum efficiency, good signal to noise ratio and high...... resolution for this spectral region. Today, an increasing number of applications exists outside the spectral region covered by Si-based devices, e.g. within cleantech, medical or food imaging. We present a technology based on wavelength conversion which will extend the spectral coverage of state of the art...... visible or near infrared cameras and spectrometers to include other spectral regions of interest....

  8. HST/ACS IMAGING OF OMEGA CENTAURI: OPTICAL COUNTERPARTS OF CHANDRA X-RAY SOURCES

    International Nuclear Information System (INIS)

    Cool, Adrienne M.; Arias, Tersi; Brochmann, Michelle; Dorfman, Jason; Gafford, April; White, Vivian; Haggard, Daryl; Anderson, Jay

    2013-01-01

    We present results of a search for optical counterparts of X-ray sources in and toward the globular cluster Omega Centauri (NGC 5139) using the Advanced Camera for Surveys (ACS) on the Hubble Space Telescope. The ACS data consist of a mosaic of Wide Field Channel images obtained using F625W, F435W, and F658N filters; with nine pointings we cover the central ∼10' × 10' of the cluster and encompass 109 known Chandra sources. We find promising optical counterparts for 59 of the sources, ∼40 of which are likely to be associated with the cluster. These include 27 candidate cataclysmic variables (CVs), 24 of which are reported here for the first time. Fourteen of the CV candidates are very faint, with absolute magnitudes in the range M 625 =10.4-12.6, making them comparable in brightness to field CVs near the period minimum discovered in the Sloan Digital Sky Survey. Additional optical counterparts include three BY Dra candidates, a possible blue straggler, and a previously reported quiescent low-mass X-ray binary. We also identify 3 foreground stars and 11 probable active galactic nuclei. Finally, we report the discovery of a group of seven stars whose X-ray properties are suggestive of magnetically active binaries, and whose optical counterparts lie on or very near the metal-rich anomalous giant and subgiant branches in ω Cen. If the apparent association between these seven stars and the RGB/SGB-a stars is real, then the frequency of X-ray sources in this metal-rich population is enhanced by a factor of at least five relative to the other giant and subgiant populations in the cluster. If these stars are not members of the metal-rich population, then they bring the total number of red stragglers (also known as sub-subgiants) that have been identified in ω to Cen 20, the largest number yet known in any globular cluster.

  9. Understanding possible electromagnetic counterparts to loud gravitational wave events: Binary black hole effects on electromagnetic fields

    International Nuclear Information System (INIS)

    Palenzuela, Carlos; Lehner, Luis; Yoshida, Shin

    2010-01-01

    In addition to producing loud gravitational waves, the dynamics of a binary black hole system could induce emission of electromagnetic radiation by affecting the behavior of plasmas and electromagnetic fields in their vicinity. We study how the electromagnetic fields are affected by a pair of orbiting black holes through the merger. In particular, we show how the binary's dynamics induce a variability in possible electromagnetically induced emissions as well as an enhancement of electromagnetic fields during the late-merge and merger epochs. These time dependent features will likely leave their imprint in processes generating detectable emissions and can be exploited in the detection of electromagnetic counterparts of gravitational waves.

  10. Observations of optical counterparts of high-energy sources with ESA Gaia

    Czech Academy of Sciences Publication Activity Database

    Hudec, René; Šimon, Vojtěch; Hudec, L.

    2008-01-01

    Roč. 8, spec. iss. (2008), s. 386-392 ISSN 1009-9271. [International workshop on multifrequency behaviour of high energy cosmic sources. Vulcano, 28.05.2007-02.06.2007] R&D Projects: GA AV ČR IAA3003206; GA ČR GA205/05/2167 Grant - others:ESA(XE) ESA-PECS project No. 98023; ESA(CZ) ESA-PECS project No. 98058 Institutional research plan: CEZ:AV0Z10030501 Keywords : high-energy sources * optical counterparts Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics Impact factor: 0.689, year: 2008

  11. Do Lower Calorie or Lower Fat Foods Have More Sodium Than Their Regular Counterparts?

    Directory of Open Access Journals (Sweden)

    Katherine A. John

    2016-08-01

    Full Text Available The objective of this study was to compare the sodium content of a regular food and its lower calorie/fat counterpart. Four food categories, among the top 20 contributing the most sodium to the US diet, met the criteria of having the most matches between regular foods and their lower calorie/fat counterparts. A protocol was used to search websites to create a list of “matches”, a regular and comparable lower calorie/fat food(s under each brand. Nutrient information was recorded and analyzed for matches. In total, 283 matches were identified across four food categories: savory snacks (N = 44, cheese (N = 105, salad dressings (N = 90, and soups (N = 44. As expected, foods modified from their regular versions had significantly reduced average fat (total fat and saturated fat and caloric profiles. Mean sodium content among modified salad dressings and cheeses was on average 8%–12% higher, while sodium content did not change with modification of savory snacks. Modified soups had significantly lower mean sodium content than their regular versions (28%–38%. Consumers trying to maintain a healthy diet should consider that sodium content may vary in foods modified to be lower in calories/fat.

  12. Probing extra dimension through gravitational wave observations of compact binaries and their electromagnetic counterparts

    Science.gov (United States)

    Yu, Hao; Gu, Bao-Min; Huang, Fa Peng; Wang, Yong-Qiang; Meng, Xin-He; Liu, Yu-Xiao

    2017-02-01

    The future gravitational wave (GW) observations of compact binaries and their possible electromagnetic counterparts may be used to probe the nature of the extra dimension. It is widely accepted that gravitons and photons are the only two completely confirmed objects that can travel along null geodesics in our four-dimensional space-time. However, if there exist extra dimensions and only GWs can propagate freely in the bulk, the causal propagations of GWs and electromagnetic waves (EMWs) are in general different. In this paper, we study null geodesics of GWs and EMWs in a five-dimensional anti-de Sitter space-time in the presence of the curvature of the universe. We show that for general cases the horizon radius of GW is longer than EMW within equal time. Taking the GW150914 event detected by the Advanced Laser Interferometer Gravitational-Wave Observatory and the X-ray event detected by the Fermi Gamma-ray Burst Monitor as an example, we study how the curvature k and the constant curvature radius l affect the horizon radii of GW and EMW in the de Sitter and Einstein-de Sitter models of the universe. This provides an alternative method for probing extra dimension through future GW observations of compact binaries and their electromagnetic counterparts.

  13. Off-axis short GRBs from structured jets as counterparts to GW events

    Science.gov (United States)

    Kathirgamaraju, Adithan; Barniol Duran, Rodolfo; Giannios, Dimitrios

    2018-01-01

    Binary neutron star mergers are considered to be the most favourable sources that produce electromagnetic (EM) signals associated with gravitational waves (GWs). These mergers are the likely progenitors of short duration gamma-ray bursts (GRBs). The brief gamma-ray emission (the 'prompt' GRB emission) is produced by ultrarelativistic jets, as a result, this emission is strongly beamed over a small solid angle along the jet. It is estimated to be a decade or more before a short GRB jet within the Laser Interferometer Gravitational-Wave observatory (LIGO) volume points along our line of sight. For this reason, the study of the prompt signal as an EM counterpart to GW events has been sparse. We argue that for a realistic jet model, one whose luminosity and Lorentz factor vary smoothly with angle, the prompt signal can be detected for a significantly broader range of viewing angles. This can lead to an 'off-axis' short GRB as an EM counterpart. Our estimates and simulations show that it is feasible to detect these signals with the aid of the temporal coincidence from a LIGO trigger, even if the observer is substantially misaligned with respect to the jet.

  14. A CANDIDATE OPTICAL COUNTERPART TO THE MIDDLE AGED γ -RAY PULSAR PSR J1741–2054

    Energy Technology Data Exchange (ETDEWEB)

    Mignani, R. P.; Marelli, M.; Luca, A. De; Salvetti, D.; Belfiore, A. [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica Milano, via E. Bassini 15, I-20133, Milano (Italy); Testa, V. [INAF—Osservatorio Astronomico di Roma, via Frascati 33, I-00040, Monteporzio (Italy); Pierbattista, M. [Department of Astrophysics and Theory of Gravity, Maria Curie-Sklodowska University, ul. Radziszewskiego 10, 20-031 Lublin (Poland); Razzano, M. [Istituto Nazionale di Fisica Nucleare, Sezione di Pisa, I-56127 Pisa (Italy); Shearer, A.; Moran, P. [Centre for Astronomy, National University of Ireland, Newcastle Road, Galway (Ireland)

    2016-07-10

    We carried out deep optical observations of the middle aged γ -ray pulsar PSR J1741−2054 with the Very Large Telescope (VLT). We identified two objects, of magnitudes m {sub v} = 23.10 ± 0.05 and m {sub v} = 25.32 ± 0.08, at positions consistent with the very accurate Chandra coordinates of the pulsar, the faintest of which is more likely to be its counterpart. From the VLT images we also detected the known bow-shock nebula around PSR J1741−2054. The nebula is displaced by ∼0.″9 (at the 3 σ confidence level) with respect to its position measured in archival data, showing that the shock propagates in the interstellar medium consistently with the pulsar proper motion. Finally, we could not find evidence of large-scale extended optical emission associated with the pulsar wind nebula detected by Chandra , down to a surface brightness limit of ∼28.1 mag arcsec{sup −2}. Future observations are needed to confirm the optical identification of PSR J1741−2054 and characterize the spectrum of its counterpart.

  15. Characterization of maize allergens - MON810 vs. its non-transgenic counterpart.

    Science.gov (United States)

    Fonseca, Cátia; Planchon, Sébastien; Renaut, Jenny; Oliveira, Maria Margarida; Batista, Rita

    2012-04-03

    One of the main concerns about genetically modified foods and their potential impacts on human health is that the introduction of a new/ altered gene may putatively alter the expression of others, namely endogenous allergens. We intended to evaluate, and to compare, using quantitative real time RT-PCR technique, the expression of 5 already known maize allergens (Zea m14, Zea m25, Zea m27kD, 50kD Zein and trypsin inhibitor) in MON 810 vs. its non-transgenic counterpart, throughout seed development (10, 16 and 23days after pollination). We have shown that none of the tested allergen genes presented differential expression, with statistic significance, along all tested seed development stages, in MON810 vs. its conventional counterpart. We have also used bidimensional gel electrophoresis followed by Western blotting with plasma from two maize allergic subjects to characterize their immunologic responses against MON 810 vs. its non-transgenic control. Immunoreactive spots were characterized by MS. We have identified fourteen new IgE-binding proteins present in both transgenic and non-transgenic maize. Copyright © 2012 Elsevier B.V. All rights reserved.

  16. Acute mixture toxicity of halogenated chemicals and their next generation counterparts on zebrafish embryos.

    Science.gov (United States)

    Godfrey, Amy; Abdel-Moneim, Ahmed; Sepúlveda, Maria S

    2017-08-01

    Perfluorinated chemicals and flame retardants are halogenated compounds commonly used in food packaging and in clothing and electronics, respectively. Due to the hazardous effects of many of these chemicals, manufacturers are developing next generation potential less toxic alternatives. The objective of this study was to assess the toxicity of potentially "safer" alternatives, singly and in mixtures, in relation to their first generation counterparts. We used zebrafish embryos as our model organism due to its high structural and functional homology to other vertebrates and its suitability for early developmental studies. We tested three well studied halogens, perfluorooctanoic acid (PFOA), tris (1,3-dichloro-2-propyl) phosphate (TDCPP) and tetrabromobisphenal A (TBBPA), and two less-studied next generation chemicals, 9,10-Dihydro-9-oxa-10-phosphaphenanthrene 10-oxide (DOPO) and perfluorobutyric acid (PFBA). First, we identified their lethal concentration (LC 50 ) under 96 h exposures using zebrafish embryos; chemical LC50 values ranged from 1.3 to 13,795 ppm. Next, we tested the toxicity of tertiary mixtures containing the estimated LC 50 values for each chemical which ranged from 126 to 5,094 ppm. We found that chemicals within these mixtures displayed concentration addition suggesting a similar mode of toxic action. Importantly, next generation chemicals were less acutely toxic singly and in mixtures than their first generation counterpart. Copyright © 2017 Elsevier Ltd. All rights reserved.

  17. Tribological Response of Heat Treated AISI 52100 Steels Against Steel and Ceramic Counterparts

    Directory of Open Access Journals (Sweden)

    Türedi E.

    2017-09-01

    Full Text Available AISI 52100 bearing steels are commonly used in applications requiring high hardness and abrasion resistance. The bearing steels are working under dynamic loads in service conditions and their toughness properties become important. In order to provide the desired mechanical properties, various heat treatments (austenizing, quenching and tempering are usually applied. In this study, AISI 52100 bearing steel samples were austenized at 900°C for ½ h and water quenched to room temperature. Then tempering was carried out at 795°C, 400°C and 200°C for ½ h. In order to investigate the effect of heat treatment conditions on wear behavior, dry friction tests were performed according to ASTM G99-05 Standard with a ‘ball-on-disk’ type tribometer. The samples were tested against steel and ceramic counterparts using the parameters of 100 m distance and 30 N load and 0.063 m/s rotational speed. After wear test, the surface characterization was carried out using microscopy. Wear loss values were calculated using a novel optical method on both flat and counterpart specimens.

  18. Hybrid spectral CT reconstruction

    Science.gov (United States)

    Clark, Darin P.

    2017-01-01

    Current photon counting x-ray detector (PCD) technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID). In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM). Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with a spectral

  19. Context Dependent Spectral Unmixing

    Science.gov (United States)

    2014-08-01

    remote sensing [1–13]. It is also used in food safety [14–17], pharmaceutical process monitoring and quality control [18–22], as well as in biomedical...23,24], industrial [25], biometric [26] and forensic applications [27]. Hyperspectral sensors capture both the spatial and spectral information of a...imagery,” IEEE Signal Processing Magazine, vol. 19, no. 1, pp. 58–69, 2002. [12] A. Plaza, J. A. Benediktsson, J. W. Boardman, J. Brazile , L. Bruzzone, G

  20. Hybrid spectral CT reconstruction.

    Directory of Open Access Journals (Sweden)

    Darin P Clark

    Full Text Available Current photon counting x-ray detector (PCD technology faces limitations associated with spectral fidelity and photon starvation. One strategy for addressing these limitations is to supplement PCD data with high-resolution, low-noise data acquired with an energy-integrating detector (EID. In this work, we propose an iterative, hybrid reconstruction technique which combines the spectral properties of PCD data with the resolution and signal-to-noise characteristics of EID data. Our hybrid reconstruction technique is based on an algebraic model of data fidelity which substitutes the EID data into the data fidelity term associated with the PCD reconstruction, resulting in a joint reconstruction problem. Within the split Bregman framework, these data fidelity constraints are minimized subject to additional constraints on spectral rank and on joint intensity-gradient sparsity measured between the reconstructions of the EID and PCD data. Following a derivation of the proposed technique, we apply it to the reconstruction of a digital phantom which contains realistic concentrations of iodine, barium, and calcium encountered in small-animal micro-CT. The results of this experiment suggest reliable separation and detection of iodine at concentrations ≥ 5 mg/ml and barium at concentrations ≥ 10 mg/ml in 2-mm features for EID and PCD data reconstructed with inherent spatial resolutions of 176 μm and 254 μm, respectively (point spread function, FWHM. Furthermore, hybrid reconstruction is demonstrated to enhance spatial resolution within material decomposition results and to improve low-contrast detectability by as much as 2.6 times relative to reconstruction with PCD data only. The parameters of the simulation experiment are based on an in vivo micro-CT experiment conducted in a mouse model of soft-tissue sarcoma. Material decomposition results produced from this in vivo data demonstrate the feasibility of distinguishing two K-edge contrast agents with

  1. Spectral distributions and symmetries

    International Nuclear Information System (INIS)

    Quesne, C.

    1980-01-01

    As it is now well known, the spectral distribution method has both statistical and group theoretical aspects which make for great simplifications in many-Fermion system calculations with respect to more conventional ones. Although both aspects intertwine and are equally essential to understand what is going on, we are only going to discuss some of the group theoretical aspects, namely those connected with the propagation of information, in view of their fundamental importance for the actual calculations of spectral distributions. To be more precise, let us recall that the spectral distribution method may be applied in principle to many-Fermion spaces which have a direct-product structure, i.e., are obtained by distributing a certain number n of Fermions over N single-particle states (O less than or equal to n less than or equal to N), as it is the case for instance for the nuclear shell model spaces. For such systems, the operation of a central limit theorem is known to provide us with a simplifying principle which, when used in conjunction with exact or broken symmetries, enables us to make definite predictions in those cases which are not amendable to exact shell model diagonalizations. The distribution (in energy) of the states corresponding to a fixed symmetry is then defined by a small number of low-order energy moments. Since the Hamiltonian is defined in few-particle subspaces embedded in the n-particlespace, the low-order moments, we are interested in, can be expressed in terms of simpler quantities defined in those few-particle subspaces: the information is said to propagate from the simple subspaces to the more complicated ones. The possibility of actually calculating spectral distributions depends upon the finding of simple ways to propagate the information

  2. Spectral and Diffraction Tomography

    OpenAIRE

    Lionheart, William

    2016-01-01

    We discuss several cases of what we call "Rich Tomography" problems in which more data is measured than a scalar for each ray. We give examples of infra red spectral tomography and Bragg edge neutron tomography in which the data is insufficient. For diffraction tomography of strain for polycrystaline materials we give an explicit reconstruction procedure. We go on to describe a way to find six independent rotation axes using Pascal's theorem of projective geometry

  3. Mechanical spectral shift reactor

    International Nuclear Information System (INIS)

    Wilson, J.F.; Sherwood, D.G.

    1982-01-01

    A mechanical spectral shift reactor comprises a reactive core having fuel assemblies accommodating both water displacer elements and neutron absorbing control rods for selectively changing the volume of water-moderator in the core. The fuel assemblies with displacer and control rods are arranged in alternating fashion so that one displacer element drive mechanism may move displacer elements in more than one fuel assembly without interfering with the movement of control rods of a corresponding control rod drive mechanisms. (author)

  4. The isolated neutron star RBS1774 revisited. Revised XMM-Newton X-ray parameters and an optical counterpart from deep LBT-observations

    Science.gov (United States)

    Schwope, A. D.; Erben, T.; Kohnert, J.; Lamer, G.; Steinmetz, M.; Strassmeier, K.; Zinnecker, H.; Bechtold, J.; Diolaiti, E.; Fontana, A.; Gallozzi, S.; Giallongo, E.; Ragazzoni, R.; de Santis, C.; Testa, V.

    2009-05-01

    We report optical B-band observations with the Large Binocular Telescope (LBT) of the isolated neutron star RBS1774. The stacked image with a total exposure of 2fh5 reveals a candidate optical counterpart at mB = 26.96 ± 0.20 at position α (2000) = 21^h43^m03fs40, δ(2000) = +06degr54^prime17farcs5, within the joint Chandra and XMM-Newton error circles. We analyse archival XMM-Newton observations and derive revised spectral and positional parameters. The predicted optical flux from the extrapolated X-ray spectrum is likely twice as high as reported before. The measured optical flux exceeds the extrapolated X-ray spectral flux by a factor ˜40 (15-60 at 1σ confidence). We interpret our detection and the spectral energy distribution as further evidence of a temperature structure over the neutron star's surface and present a pure thermal model reflecting both the SED and the pulsed fraction of the light curve. Based on observations obtained with XMM-Newton, an ESA science mission with instruments and contributions directly funded by ESA Member States and NASA. Based on data acquired using the Large Binocular Telescope (LBT). The LBT is an international collaboration among institutions in the US, Italy, and Germany. LBT Corporation partners are the University of Arizona, on behalf of the Arizona university system; Istituto Nazionale di Astrofisica, Italy; LBT Beteiligungsgesellschaft, Germany, representing the Max Planck Society, the Astrophysical Institute Potsdam, and Heidelberg University; Ohio State University; and the Research Corporation, on behalf of the University of Notre Dame, the University of Minnesota, and the University of Virginia.

  5. New spectral types in NGC 3603

    Science.gov (United States)

    Morrell, N.; Melena, N.; Massey, P.; Zangari, A.

    NGC 3603 is a giant H II region known to harbor a large population of massive stars. Its central cluster is the closest galactic counterpart to the R136 cluster in 30 Dor, in the Large Magellanic Cloud (Walborn 1973). It is very compact (76 arcsecs in diameter) which makes it an extremely difficult target for individual stars spectroscopy. Some stars lying mostly in the periphery of NGC 3603 have been classified from the ground by Moffat (1983), but for the highly crowded core only one study was available at present (Drissen et al. 1995), which was performed with the Faint Object Spectrograph on board of the Hubble Space Telescope (HST). Among the massive members of NGC 3603 there are some of the objects showing H-rich WN + abs spectra, also found in the R136 cluster in 30 Doradus (Massey & Hunter 1998). During 2 nights in April 2006, we have made use of the excellent seeing and large aperture of the Magellan telescopes to obtain individual spectroscopy for stars in the crowded core of NGC 3603. We used the IMACS spectrograph in F4 mode at the Baade (Magellan I) telescope, with a 600 l/mm grating and a 0.7 arcsec long slit. From these observations we were able to derive new spectral types for 26 stars: 16 of which are classified here for the first time, while for the remaining 10 we have revised previous spectral classifications, finding very good general agreement, but exact coincidence for only 2 of them. This rises to 38 the number of stars in this massive star forming region, for which spectral classification is available. Not surprisingly, most of the newly classified spectra belong to the earliest O-subtypes. This work is part of a more comprehensive study (Melena et al. 2007) in which archival HST/ACS-HRC images (P.I. Maiz-Apellaniz) have been used to derive new photometry for stars in the cluster, including those for which there is spectroscopy. Having new spectral types and improved photometry, allowed us to determine new values for the reddening (E (B

  6. Experiment data report for semiscale Mod-1 Test S-06-2 (LOFT counterpart test). [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Patton, Jr., M. L.; Collins, B. L.; Sackett, K. E.

    1977-08-01

    Recorded test data are presented for Test S-06-2 of the Semiscale Mod-1 LOFT counterpart test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying an hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-06-2 was conducted from initial conditions of 15 513 kPa and 563 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact loop to simulate emergency core coolant injection in a PWR. The heater rods in the electrically heated core were operated at an axial peak power density which was 50% of the maximum peak power density (52.5 kW/m).

  7. Experiment data report for semiscale Mod-1 test S-06-1 (LOFT counterpart test). [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Collins, B. L.; Patton, Jr., M. L.; Sackett, K. E.

    1977-07-01

    Recorded test data are presented for Test S-06-1 of the Semiscale Mod-1 LOFT counterpart test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying an hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-06-1 was conducted from initial conditions of 15 568 kPa and 564 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact loop to simulate emergency core coolant injection in a PWR. The heater rods in the electrically heated core were operated at an axial peak power density which was 30% of the maximum peak power density (52.5 kW/m).

  8. Experiment data report for semiscale Mod-1 test S-06-4 (LOFT counterpart test)

    Energy Technology Data Exchange (ETDEWEB)

    Gillins, R. L.; Sackett, K. E.; Coppin, C. E.

    1977-12-01

    Recorded test data are presented for Test S-06-4 of the Semiscale Mod-1 LOFT counterpart test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-06-4 was conducted from initial conditions of 15,653 kPa and 564 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact loop to simulate emergency core coolant injection in a PWR. The heater rods in the electrically heated core were operated at an axial peak power density which was 100 percent of the maximum peak power density (52.5 kW/m).

  9. Spatial integration by a dielectric slab and its planar graphene-based counterpart.

    Science.gov (United States)

    Zangeneh-Nejad, Farzad; Khavasi, Amin

    2017-05-15

    In this contribution a new approach to perform spatial integration is presented using a dielectric slab. Our approach is indeed based on the fact that the transmission coefficient of a simple dielectric slab at its mode excitation angle matches the Fourier-Green's function of first-order integration. Inspired by the mentioned dielectric-based integrator, we further demonstrate its graphene-based counterpart. The latter is not only reconfigurable but also highly miniaturized in contrast to the previously reported designs [Opt. Commun.338, 457 (2015)OPCOB80030-401810.1016/j.optcom.2014.11.007]. Such integrators have the potential to be used in ultrafast analog computation and signal processing.

  10. Chitosan nanoparticles and their Tween 80 modified counterparts disrupt the developmental profile of zebrafish embryos.

    Science.gov (United States)

    Yuan, Zhongyue; Li, Ying; Hu, Yulan; You, Jian; Higashisaka, Kazuma; Nagano, Kazuya; Tsutsumi, Yasuo; Gao, Jianqing

    2016-12-30

    Chitosan nanoparticles (CS-NPs) and their Tween 80 modified counterparts (TmCS-NPs) are among the most commonly used brain-targeted vehicles. However, their potential developmental toxicity is poorly understood. In this study, zebrafish embryos are introduced as an in vivo platform. Both NPs showed a dose-dependent increase in developmental toxicity (decreased hatching rate, increased mortality and incidences of malformation). Neurobehavioral changes included decreased spontaneous movement in TmCS-NP treated embryos and hyperactive effect in CS-NP treated larvae. Both NPs remarkably inhibited axonal development of primary and secondary motor neurons, and affected the muscle structure. Overall, this study demonstrated that CS-NPs and TmCS-NPs could affect embryonic development, disrupt neurobehavior of zebrafish larvae and affect muscle and neuron development, suggesting more attention on biodegradable chitosan nanoparticles. Copyright © 2016 Elsevier B.V. All rights reserved.

  11. Comparison of occupational hearing losses among military engineers and their civilian counterparts.

    Science.gov (United States)

    Fletcher, J L; Chandler, D W

    1983-10-01

    A previous study (Chandler and Fletcher, J. Aud. Res., 1983, 23, 23-32) examined group hearing loss of 209 U.S. Army engineers by comparing current with reference audiograms. The sample was categorized by military occupation specialty, age, and time on job. The present study reports comparable data for 187 civilian engineers on the same Army post exposed to essentially the same noise. These had less hearing loss than their military counterparts. Some reasons are suggested, such as attrition of the civilian workforce because of hearing problems, and a likely greater exposure of the military engineers to noises not job-related. Age was less important than time on the job. Both groups, however, exhibited significantly lower hearing levels than the industrial population of Glorig et al (Am. Acad. Ophthalmol. Otolaryngol., 1957) at the 1954 Wisconsin State Fair, possibly because both military and civilian personnel at this Army post had been for some years in an aggressive hearing conservation program.

  12. CONSTRUCTIVISM AND REFLECTIVISM AS THE LOGICAL COUNTERPARTS IN TESOL: LEARNING THEORY VERSUS TEACHING METHODOLOGY

    Directory of Open Access Journals (Sweden)

    Abdullah al Mahmud

    2013-07-01

    Full Text Available The gist of the entire constructivist learning theory is that learners are self-builders of their learning that occurs through a mental process in a social context or communication setting, and teachers as facilitators generate learning by creating the expected environment and/or utilizing the process. This article theoretically proves reflectivism as the logical counterpart of constructivism through establishing their complete interdependence andthen suggests certain strategies of reflection to be used in language teaching for ensuring the best possible constructivist learning of language learners. In doing so, the basic tenets of constructivism and reflective thoughts are elaborated, examining their mutual connection thoroughly in terms of constructivist recommendations. The research also focuses on three case studies to depict how the theory of constructivist learning principles comes into practice through judicious reviews or reflective process.

  13. Analysis of counterpart tests performed in boiling water reactor experimental simulators

    Energy Technology Data Exchange (ETDEWEB)

    Bovalini, R.; D' Auria, F.; De Varti, A.; Maugeri, P.; Mazzini, M. (Univ. degli Studi di Pisa, Dept. di Construzioni Meccaniche e Nucleari, Via Diotisalvi 2, 56100 Pisa (IT))

    1992-01-01

    In this paper the main results obtained at the University of Pisa on small-break loss-of-coolant accident counterpart experiments carried out in boiling water reactor (BWR) experimental simulators are summarized. In particular, the results of similar experiments performed in the PIPER-ONE, Full Integral Simulation Test (FIST), and ROSA-III facilities are analyzed. The tests simulate a transient originated by a small break in the recirculation line of a BWR-6 with the high-pressure injection systems unavailable. RELAPS/MOD2 nodalizations have been set up for these facilities and for the reference BWR plant. The calculated results are compared among each other and with the experimental data. Finally, the merits and the limitations of such a program are discussed in view of the evaluation of code scaling capabilities and uncertainty.

  14. Nonrelativistic counterparts of twistors and the realizations of Galilean conformal algebra

    Energy Technology Data Exchange (ETDEWEB)

    Fedoruk, S., E-mail: fedoruk@theor.jinr.r [Bogoliubov Laboratory of Theoretical Physics, JINR, 141980 Dubna, Moscow region (Russian Federation); Kosinski, P., E-mail: pkosinsk@uni.lodz.p [Department of Theoretical Physics II, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland); Lukierski, J., E-mail: lukier@ift.uni.wroc.p [Institute for Theoretical Physics, University of Wroclaw, pl. Maxa Borna 9, 50-204 Wroclaw (Poland); Maslanka, P., E-mail: pmaslan@uni.lodz.p [Department of Theoretical Physics II, University of Lodz, Pomorska 149/153, 90-236 Lodz (Poland)

    2011-05-02

    Using the notion of Galilean conformal algebra (GCA) in arbitrary space dimension d, we introduce for d=3 quantized nonrelativistic counterpart of twistors as the spinorial representation of SO(2,1)+SO(3) which is the maximal semisimple subalgebra of three-dimensional GCA. The GC-covariant quantization of such nonrelativistic spinors, which shall be called also Galilean twistors, is presented. We consider for d=3 the general spinorial matrix realizations of GCA, which are further promoted to quantum-mechanical operator representations, expressed as bilinears in quantized Galilean twistors components. For arbitrary Hermitian quantum-mechanical Galilean twistor realizations we obtain the result that the representations of GCA with positive-definite Hamiltonian do not exist. For non-positive H we construct for N{>=}2 the Hermitian Galilean N-twistor realizations of GCA; for N=2 such realization is provided explicitly.

  15. Strategic Wholesale Pricing for an Incumbent Supplier Facing with a Competitive Counterpart

    Directory of Open Access Journals (Sweden)

    Jianwu Sun

    2014-01-01

    Full Text Available We introduce a wholesale pricing strategy for an incumbent supplier facing with a competitive counterpart. We propose a profit function which considers both the present loss and future loss from a wholesale price and then study the optimal wholesale prices for different objectives about this profit function for the incumbent supplier. First, we achieve an optimal wholesale price for the incumbent supplier to maximize his expected profit. Then, to reduce the risk originating from the fluctuation in the competitive supplier’s wholesale price, we integrate the conditional value-at-risk (CVaR measure in financial risk management into this study and derive an optimal wholesale price to maximize CVaR about profit for the incumbent supplier. Besides, the properties of the two optimal wholesale prices are discussed. Finally, some management insights are suggested for the incumbent supplier in a competitive setting.

  16. Strategic wholesale pricing for an incumbent supplier facing with a competitive counterpart.

    Science.gov (United States)

    Sun, Jianwu

    2014-01-01

    We introduce a wholesale pricing strategy for an incumbent supplier facing with a competitive counterpart. We propose a profit function which considers both the present loss and future loss from a wholesale price and then study the optimal wholesale prices for different objectives about this profit function for the incumbent supplier. First, we achieve an optimal wholesale price for the incumbent supplier to maximize his expected profit. Then, to reduce the risk originating from the fluctuation in the competitive supplier's wholesale price, we integrate the conditional value-at-risk (CVaR) measure in financial risk management into this study and derive an optimal wholesale price to maximize CVaR about profit for the incumbent supplier. Besides, the properties of the two optimal wholesale prices are discussed. Finally, some management insights are suggested for the incumbent supplier in a competitive setting.

  17. A Search for Optical Counterparts of Chandra Sources in Omega Centauri using ACS

    Science.gov (United States)

    Haggard, D.; Fuller, A. D.; Dorfman, J. L.; Cool, A. M.; Anderson, J.; Edmonds, P. D.; Davies, M. B.

    2002-12-01

    The globular cluster Omega Centauri, with its high mass and large, moderate density core, is of interest both for its population of primordial binaries and for the large number of tidal-capture and/or exchange-collision binaries it may harbor. We have obtained a 3x3 mosaic of Wide Field Camera pointings with HST's Advanced Camera for Surveys, covering a 10'x10' field out to the cluster's half-mass radius. Containing ~1.7 million detected stars, the resulting mosaic represents the most complete image of Omega Cen yet obtained. Here we report preliminary findings of a search in these data for optical counterparts to more than 100 faint X-ray sources (Lx ~ 2 x 1030 - 5 x 1032 erg-s-1) detected in our prior study of Omega Cen using the Chandra X-ray Observatory. Cluster X-ray sources are likely to consist primarily of accreting binary stars and close detached binaries with active coronae. Significant numbers of active galaxies in the background are also expected to be present. Using B, R, and H-alpha images, we are searching for optical counterparts that are H-alpha-bright and blue, as signatures of accretion in cataclysmic variables and/or quiescent low-mass X-ray binaries. Active binaries (e.g., BY Draconis stars) may appear as weaker H-alpha emitters lying on or slightly redward of the main sequence. This work is supported by NASA grant GO-9442 from the Space Telescope Science Institute.

  18. Subaru Hyper Suprime-Cam Survey for an optical counterpart of GW170817

    Science.gov (United States)

    Tominaga, Nozomu; Tanaka, Masaomi; Morokuma, Tomoki; Utsumi, Yousuke; Yamaguchi, Masaki S.; Yasuda, Naoki; Tanaka, Masayuki; Yoshida, Michitoshi; Fujiyoshi, Takuya; Furusawa, Hisanori; Kawabata, Koji S.; Lee, Chien-Hsiu; Motohara, Kentaro; Ohsawa, Ryou; Ohta, Kouji; Terai, Tsuyoshi; Abe, Fumio; Aoki, Wako; Asakura, Yuichiro; Barway, Sudhanshu; Bond, Ian A.; Fujisawa, Kenta; Honda, Satoshi; Ioka, Kunihito; Itoh, Youichi; Kawai, Nobuyuki; Kim, Ji Hoon; Koshimoto, Naoki; Matsubayashi, Kazuya; Miyazaki, Shota; Saito, Tomoki; Sekiguchi, Yuichiro; Sumi, Takahiro; Tristram, Paul J.

    2018-03-01

    We perform a z-band survey for an optical counterpart of the binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers 23.6 deg2 corresponding to the 56.6% credible region of GW170817 and reaches the 50% completeness magnitude of 20.6 mag on average. As a result, we find 60 candidate extragalactic transients, including J-GEM17btc (also known as SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993, which is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database. Among 59 of the candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, z-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located within the 3D skymap of GW170817. The probability for J-GEM17btc is 64%, which is much higher than for the other 59 candidates (9.3 × 10-3-2.1 × 10-1%). Furthermore, the possibility that at least one of the other 59 candidates is located within the 3D skymap is only 3.2%. Therefore, we conclude that J-GEM17btc is the most likely and distinguished candidate to be the optical counterpart of GW170817.

  19. Subaru Hyper Suprime-Cam Survey for an optical counterpart of GW170817‡

    Science.gov (United States)

    Tominaga, Nozomu; Tanaka, Masaomi; Morokuma, Tomoki; Utsumi, Yousuke; Yamaguchi, Masaki S.; Yasuda, Naoki; Tanaka, Masayuki; Yoshida, Michitoshi; Fujiyoshi, Takuya; Furusawa, Hisanori; Kawabata, Koji S.; Lee, Chien-Hsiu; Motohara, Kentaro; Ohsawa, Ryou; Ohta, Kouji; Terai, Tsuyoshi; Abe, Fumio; Aoki, Wako; Asakura, Yuichiro; Barway, Sudhanshu; Bond, Ian A.; Fujisawa, Kenta; Honda, Satoshi; Ioka, Kunihito; Itoh, Youichi; Kawai, Nobuyuki; Kim, Ji Hoon; Koshimoto, Naoki; Matsubayashi, Kazuya; Miyazaki, Shota; Saito, Tomoki; Sekiguchi, Yuichiro; Sumi, Takahiro; Tristram, Paul J.

    2018-02-01

    We perform a z-band survey for an optical counterpart of the binary neutron star coalescence GW170817 with Subaru/Hyper Suprime-Cam. Our untargeted transient search covers 23.6 deg2 corresponding to the 56.6% credible region of GW170817 and reaches the 50% completeness magnitude of 20.6 mag on average. As a result, we find 60 candidate extragalactic transients, including J-GEM17btc (also known as SSS17a/DLT17ck). While J-GEM17btc is associated with NGC 4993, which is firmly located inside the 3D skymap of GW170817, the other 59 candidates do not have distance information in the GLADE v2 catalog or NASA/IPAC Extragalactic Database. Among 59 of the candidates, 58 are located at the center of extended objects in the Pan-STARRS1 catalog, while one candidate has an offset. We present location, z-band apparent magnitude, and time variability of the candidates and evaluate the probabilities that they are located within the 3D skymap of GW170817. The probability for J-GEM17btc is 64%, which is much higher than for the other 59 candidates (9.3 × 10-3-2.1 × 10-1%). Furthermore, the possibility that at least one of the other 59 candidates is located within the 3D skymap is only 3.2%. Therefore, we conclude that J-GEM17btc is the most likely and distinguished candidate to be the optical counterpart of GW170817.

  20. QCD spectral sum rules

    CERN Document Server

    Narison, Stéphan

    The aim of the book is to give an introduction to the method of QCD Spectral Sum Rules and to review its developments. After some general introductory remarks, Chiral Symmetry, the Historical Developments of the Sum Rules and the necessary materials for perturbative QCD including the MS regularization and renormalization schemes are discussed. The book also gives a critical review and some improvements of the wide uses of the QSSR in Hadron Physics and QSSR beyond the Standard Hadron Phenomenology. The author has participated actively in this field since 1978 just before the expanding success

  1. Spectral signatures of chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We present a new way of measuring chirality, via the spectral shift of photonic band gaps in one-dimensional structures. We derive an explicit mapping of the problem of oblique incidence of circularly polarized light on a chiral one-dimensional photonic crystal with negligible index contrast...... to the formally equivalent problem of linearly polarized light incident on-axis on a non-chiral structure with index contrast. We derive analytical expressions for the first-order shifts of the band gaps for negligible index contrast. These are modified to give good approximations to the band gap shifts also...

  2. On spectral pollution

    International Nuclear Information System (INIS)

    Llobet, X.; Appert, K.; Bondeson, A.; Vaclavik, J.

    1990-01-01

    Finite difference and finite element approximations of eigenvalue problems, under certain circumstances exhibit spectral pollution, i.e. the appearance of eigenvalues that do not converge to the correct value when the mesh density is increased. In the present paper this phenomenon is investigated in a homogeneous case by means of discrete dispersion relations: the polluting modes belong to a branch of the dispersion relation that is strongly distorted by the discretization method employed, or to a new, spurious branch. The analysis is applied to finite difference methods and to finite element methods, and some indications about how to avoiding polluting schemes are given. (author) 5 figs., 10 refs

  3. Intensity Conserving Spectral Fitting

    Science.gov (United States)

    Klimchuk, J. A.; Patsourakos, S.; Tripathi, D.

    2015-01-01

    The detailed shapes of spectral line profiles provide valuable information about the emitting plasma, especially when the plasma contains an unresolved mixture of velocities, temperatures, and densities. As a result of finite spectral resolution, the intensity measured by a spectrometer is the average intensity across a wavelength bin of non-zero size. It is assigned to the wavelength position at the center of the bin. However, the actual intensity at that discrete position will be different if the profile is curved, as it invariably is. Standard fitting routines (spline, Gaussian, etc.) do not account for this difference, and this can result in significant errors when making sensitive measurements. Detection of asymmetries in solar coronal emission lines is one example. Removal of line blends is another. We have developed an iterative procedure that corrects for this effect. It can be used with any fitting function, but we employ a cubic spline in a new analysis routine called Intensity Conserving Spline Interpolation (ICSI). As the name implies, it conserves the observed intensity within each wavelength bin, which ordinary fits do not. Given the rapid convergence, speed of computation, and ease of use, we suggest that ICSI be made a standard component of the processing pipeline for spectroscopic data.

  4. Spectral clustering for water body spectral types analysis

    Science.gov (United States)

    Huang, Leping; Li, Shijin; Wang, Lingli; Chen, Deqing

    2017-11-01

    In order to study the spectral types of water body in the whole country, the key issue of reservoir research is to obtain and to analyze the information of water body in the reservoir quantitatively and accurately. A new type of weight matrix is constructed by utilizing the spectral features and spatial features of the spectra from GF-1 remote sensing images comprehensively. Then an improved spectral clustering algorithm is proposed based on this weight matrix to cluster representative reservoirs in China. According to the internal clustering validity index which called Davies-Bouldin(DB) index, the best clustering number 7 is obtained. Compared with two clustering algorithms, the spectral clustering algorithm based only on spectral features and the K-means algorithm based on spectral features and spatial features, simulation results demonstrate that the proposed spectral clustering algorithm based on spectral features and spatial features has a higher clustering accuracy, which can better reflect the spatial clustering characteristics of representative reservoirs in various provinces in China - similar spectral properties and adjacent geographical locations.

  5. Spectral Automorphisms in Quantum Logics

    Science.gov (United States)

    Ivanov, Alexandru; Caragheorgheopol, Dan

    2010-12-01

    In quantum mechanics, the Hilbert space formalism might be physically justified in terms of some axioms based on the orthomodular lattice (OML) mathematical structure (Piron in Foundations of Quantum Physics, Benjamin, Reading, 1976). We intend to investigate the extent to which some fundamental physical facts can be described in the more general framework of OMLs, without the support of Hilbert space-specific tools. We consider the study of lattice automorphisms properties as a “substitute” for Hilbert space techniques in investigating the spectral properties of observables. This is why we introduce the notion of spectral automorphism of an OML. Properties of spectral automorphisms and of their spectra are studied. We prove that the presence of nontrivial spectral automorphisms allow us to distinguish between classical and nonclassical theories. We also prove, for finite dimensional OMLs, that for every spectral automorphism there is a basis of invariant atoms. This is an analogue of the spectral theorem for unitary operators having purely point spectrum.

  6. A COMPREHENSIVE STUDY OF DETECTABILITY AND CONTAMINATION IN DEEP RAPID OPTICAL SEARCHES FOR GRAVITATIONAL WAVE COUNTERPARTS

    Energy Technology Data Exchange (ETDEWEB)

    Cowperthwaite, P. S.; Berger, E., E-mail: pcowpert@cfa.harvard.edu [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States)

    2015-11-20

    The first direct detection of gravitational waves (GWs) by the ground-based Advanced LIGO/Virgo interferometers is expected to occur within the next few years. These interferometers are designed to detect the mergers of compact object binaries composed of neutron stars and/or black holes to a fiducial distance of ∼200 Mpc and a localization region of ∼100 deg{sup 2}. To maximize the science gains from such GW detections it is essential to identify electromagnetic counterparts. Among the wide range of proposed counterparts, the most promising is optical/IR emission powered by the radioactive decay of r-process elements synthesized in the neutron-rich merger ejecta—a “kilonova.” Here we present detailed simulated observations that encompass a range of strategies for kilonova searches during GW follow-up. We utilize these simulations to assess both the detectability of kilonovae and our ability to distinguish them from a wide range of contaminating transients in the large GW localization regions. We find that if pre-existing deep template images for the GW localization region are available, then nightly observations to a depth of i ≈ 24 mag and z ≈ 23 mag are required to achieve a 95% detection rate; observations that commence within ∼12 hr of trigger will also capture the kilonova peak and provide stronger constraints on the ejecta properties. We also find that kilonovae can be robustly separated from other known and hypothetical types of transients utilizing cuts on color (i − z ≳ 0.3 mag) and rise time (t{sub rise} ≲ 4 days). In the absence of a pre-existing template the observations must reach ∼1 mag deeper to achieve the same kilonova detection rate, but robust rejection of contaminants can still be achieved. Motivated by the results of our simulations we discuss the expected performance of current and future wide-field telescopes in achieving these observational goals, and find that prior to LSST the Dark Energy Camera on the Blanco 4 m

  7. Rectangular spectral collocation

    KAUST Repository

    Driscoll, Tobin A.

    2015-02-06

    Boundary conditions in spectral collocation methods are typically imposed by removing some rows of the discretized differential operator and replacing them with others that enforce the required conditions at the boundary. A new approach based upon resampling differentiated polynomials into a lower-degree subspace makes differentiation matrices, and operators built from them, rectangular without any row deletions. Then, boundary and interface conditions can be adjoined to yield a square system. The resulting method is both flexible and robust, and avoids ambiguities that arise when applying the classical row deletion method outside of two-point scalar boundary-value problems. The new method is the basis for ordinary differential equation solutions in Chebfun software, and is demonstrated for a variety of boundary-value, eigenvalue and time-dependent problems.

  8. [Review of digital ground object spectral library].

    Science.gov (United States)

    Zhou, Xiao-Hu; Zhou, Ding-Wu

    2009-06-01

    A higher spectral resolution is the main direction of developing remote sensing technology, and it is quite important to set up the digital ground object reflectance spectral database library, one of fundamental research fields in remote sensing application. Remote sensing application has been increasingly relying on ground object spectral characteristics, and quantitative analysis has been developed to a new stage. The present article summarized and systematically introduced the research status quo and development trend of digital ground object reflectance spectral libraries at home and in the world in recent years. Introducing the spectral libraries has been established, including desertification spectral database library, plants spectral database library, geological spectral database library, soil spectral database library, minerals spectral database library, cloud spectral database library, snow spectral database library, the atmosphere spectral database library, rocks spectral database library, water spectral database library, meteorites spectral database library, moon rock spectral database library, and man-made materials spectral database library, mixture spectral database library, volatile compounds spectral database library, and liquids spectral database library. In the process of establishing spectral database libraries, there have been some problems, such as the lack of uniform national spectral database standard and uniform standards for the ground object features as well as the comparability between different databases. In addition, data sharing mechanism can not be carried out, etc. This article also put forward some suggestions on those problems.

  9. Spectral Theory of Chemical Bonding

    National Research Council Canada - National Science Library

    Langhoff, P. W; Boatz, J. A; Hinde, R. J; Sheehy, J. A

    2004-01-01

    New theoretical methods are reported for obtaining the binding energies of molecules and other chemical aggregates employing the spectral eigenstates and related properties of their atomic constituents...

  10. Experiment data report for semiscale Mod-1 test S-06-6 (LOFT counterpart test). [PWR

    Energy Technology Data Exchange (ETDEWEB)

    Esparza, V.; Sackett, K. E.

    1977-09-01

    Recorded test data are presented for Test S-06-6 of the Semiscale Mod-1 LOFT counterpart test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-06-6 was conducted from initial conditions of 15 792 kPa and 563 K to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold leg of the intact loop to simulate emergency core coolant injection in a PWR. The heater rods in the electrically heated core were operated at an axial peak power density which was 75% of the maximum peak power density (52.5 kW/m). Test S-06-6 also evaluated the effect of special hardware assumptions on the core response.

  11. Experiment data report for semiscale Mod-1 Test S-06-5. (LOFT counterpart test). [PWR

    Energy Technology Data Exchange (ETDEWEB)

    None

    1977-06-01

    Recorded test data are presented for Test S-06-5 of the Semiscale Mod-1 LOFT counterpart test series. These tests are among several Semiscale Mod-1 experiments conducted to investigate the thermal and hydraulic phenomena accompanying a hypothesized loss-of-coolant accident in a pressurized water reactor (PWR) system. Test S-06-5 was conducted from initial conditions of 2272 psia and 536/sup 0/F to investigate the response of the Semiscale Mod-1 system to a depressurization and reflood transient following a simulated double-ended offset shear of the broken loop cold leg piping. During the test, cooling water was injected into the cold legs of the intact and broken loops to simulate emergency core coolant injection in a PWR. The purpose of Test S-06-5 was to assess the influence of the break nozzle geometry on core thermal and system response and on the subcooled and low quality mass flow rates at the break locations.

  12. Moringa oleifera Root Induces Cancer Apoptosis more Effectively than Leave Nanocomposites and Its Free Counterpart

    Science.gov (United States)

    Abd-Rabou, Ahmed A; Abdalla, Aboelfetoh M; Ali, Naglaa A; Zoheir, Khairy MA

    2017-01-01

    Medicinal plants are important elements of indigenous medical system that have persisted in developing countries. Many of the botanical chemo-preventions currently used as potent anticancer agents. However, some important anticancer agents are still extracted from plants because they cannot be synthesized chemically on a commercial scale due to their complex structures that often contain several chiral centers. The aim of this study was to test different extracts from the Moringa oleifera leaves (ML), its PLGA-CS-PEG nanocomposites (MLn), as well as root core (Rc) and outer (Ro) parts for activity against hepatocarcinoma HepG2, breast MCF7, and colorectal HCT 116/ Caco-2 cells in vitro. Nano-composites were prepared and characterized. Then, the nanocomposites and the free counterparts were screened on different propagated cancer cell lines. The underlying cytotoxic impact was followed using apoptosis measurements. All extracts kill the different cancer cells with different ratios, but intriguingly, the root core extract could kill the majority of cancer cells (approximately 70-80%), while sparing normal BHK-21 cells with minimal inhibitory effect (approximately 30-40%). Apoptotic cell increment came to confirm the cytotoxic effects of these extracts on HCT 116 cells (Rc: 212% and Ro: 180%, respectively) and HepG2 cells (ML: 567.5% and MLn: 608%, respectively) compared to control (100%) mechanistically wise. Moringa oleifera nanocomposites may have potential for use as a natural source of anti-cancer compounds. PMID:28843248

  13. Elaboration of a guideline for counterpart testing of integral loop systems

    International Nuclear Information System (INIS)

    Karwat, H.

    1988-01-01

    A previous study on the problems of scaling and extrapolation of experimental results indicated the necessity to overcome some uncertainty in the achievable code accuracy when applied to full size reactor systems. The empirical approach in simulating interfacial relationships within systems behaviour codes in combination with the liberty of nodalisation requires a careful assessment of the overall validity of the code verification concept. Several new test facilities are presently under construction to study fluid-dynamic effects of interest for the behaviour of PWRs under small break LOCA conditions in a larger dimension and with somewhat modified scaling considerations. The test results expected from these new facilities may be useful to assess the overall validity of the analytical simulation concept of the applied computer codes. Test facilities of interest within the European Community are the - LOBI Test Facility (vol. scaling 1/700) at JRC-Ispra - SPES Test Facility (vol. scaling 1/425) in Italy - BETHSY Facility (vol scaling 1/100) in France and outside Europe the - ROSA IV Facility (vol. scaling 1/50) in Japan. Main objective of the study was the elaboration of a guideline for the particular requirements of meaningful counterpart testing with the final aim to qualify the overall validity of code simulation concepts and the expected predictive accuracy of code applications for full size prototype PWRs

  14. Combining Gravitational Wave Events with their Electromagnetic Counterparts: A Realistic Joint False-Alarm Rate

    Science.gov (United States)

    Ackley, Kendall; Eikenberry, Stephen; Klimenko, Sergey; LIGO Team

    2017-01-01

    We present a false-alarm rate for a joint detection of gravitational wave (GW) events and associated electromagnetic (EM) counterparts for Advanced LIGO and Virgo (LV) observations during the first years of operation. Using simulated GW events and their recostructed probability skymaps, we tile over the error regions using sets of archival wide-field telescope survey images and recover the number of astrophysical transients to be expected during LV-EM followup. With the known GW event injection coordinates we inject artificial electromagnetic (EM) sources at that site based on theoretical and observational models on a one-to-one basis. We calculate the EM false-alarm probability using an unsupervised machine learning algorithm based on shapelet analysis which has shown to be a strong discriminator between astrophysical transients and image artifacts while reducing the set of transients to be manually vetted by five orders of magnitude. We also show the performance of our method in context with other machine-learned transient classification and reduction algorithms, showing comparability without the need for a large set of training data opening the possibility for next-generation telescopes to take advantage of this pipeline for LV-EM followup missions.

  15. Comparative evaluation of corrosion behaviour of type K thin film thermocouple and its bulk counterpart

    International Nuclear Information System (INIS)

    Mukherjee, S.K.; Barhai, P.K.; Srikanth, S.

    2011-01-01

    Highlights: → Anodic vacuum arc deposited chromel and alumel films are more 'noble' in 5% NaCl solution than their respective wires. → Chromel undergoes localised corrosion while alumel shows uniform corrosion. → Virgin samples of chromel-alumel TFTCs exhibit good thermoelectric response. → Their thermoelectric outputs remain largely unaffected when shelved under normal atmospheric conditions. → After 288 h of exposure in salt spray environment, their thermoelectric outputs show noticeable change due to size effects. - Abstract: This paper investigates the corrosion behaviour of type K thermoelements and their thin films, and compares the performance of chromel-alumel thin film thermocouple with its wire counterpart before and after exposure to 5% NaCl medium. Potentiodynamic polarisation tests reveal that chromel and alumel films are more 'noble' than their respective wires. Alumel corrodes faster when coupled with chromel in films than as wires. Secondary electron micrographs and electrochemical impedance spectroscopy measurements suggest that chromel shows localised corrosion while alumel undergoes uniform corrosion. Corrosion adversely affects the thermocouple output and introduces an uncertainty in the measurement.

  16. BurstCube: A CubeSat for Gravitational Wave Counterparts

    Science.gov (United States)

    Perkins, Jeremy S.; Racusin, Judith; Briggs, Michael; de Nolfo, Georgia; Caputo, Regina; Krizmanic, John; McEnery, Julie E.; Shawhan, Peter; Morris, David; Connaughton, Valerie; Kocevski, Dan; Wilson-Hodge, Colleen A.; Hui, Michelle; Mitchell, Lee; McBreen, Sheila

    2018-01-01

    We present BurstCube, a novel CubeSat that will detect and localize Gamma-ray Bursts (GRBs). BurstCube is a selected mission that will detect long GRBs, attributed to the collapse of massive stars, short GRBs (sGRBs), resulting from binary neutron star mergers, as well as other gamma-ray transients in the energy range 10-1000 keV. sGRBs are of particular interest because they are predicted to be the counterparts of gravitational wave (GW) sources soon to be detectable by LIGO/Virgo. BurstCube contains 4 CsI scintillators coupled with arrays of compact low-power Silicon photomultipliers (SiPMs) on a 6U Dellingr bus, a flagship modular platform that is easily modifiable for a variety of 6U CubeSat architectures. BurstCube will complement existing facilities such as Swift and Fermi in the short term, and provide a means for GRB detection, localization, and characterization in the interim time before the next generation future gamma-ray mission flies, as well as space-qualify SiPMs and test technologies for future use on larger gamma-ray missions. The ultimate configuration of BurstCube is to have a set of ~10 BurstCubes to provide all-sky coverage to GRBs for substantially lower cost than a full-scale mission.

  17. Do Asian women do as well as their Caucasian counterparts in IVF treatment: Cohort study.

    Science.gov (United States)

    Kan, Andrew; Leung, Peter; Luo, Kehui; Fay, Louise; Tan, Chunyan Leeann

    2015-06-01

    To evaluate if there is a difference in pregnancy rate between Asian and Caucasian women when they undergo in vitro fertilization (IVF). This was a retrospective cohort study set in a private reproductive medicine clinic. The study consisted of a total of 2594 patients (Asian, n = 522; Caucasian, n = 2072) undergoing IVF managed by a single doctor over a 10 year period. The main outcome measures were clinical pregnancy rate and live birth rate. Logistic regression was used to control for confounding factors. Asian women achieved a significantly lower clinical pregnancy and live birth rate than their Caucasian counterparts, despite replacement of more embryos. This difference was not significant after controlling for age and duration of infertility. Despite higher doses of gonadotrophin, they achieved fewer oocytes and had resultant fewer embryos for transfer or cryopreservation. In a study designed to reduce the effect of confounding factors by looking at a large number of patients from a single IVF unit under the care of a single doctor, there does not appear to be a difference in IVF pregnancy rate as a result of race. Asian women tend to present for IVF treatment at a later age after having tried for a longer period of time and this contributes significantly to their lower pregnancy rate. © 2014 The Authors. Journal of Obstetrics and Gynaecology Research © 2014 Japan Society of Obstetrics and Gynecology.

  18. J-GEM observations of an electromagnetic counterpart to the neutron star merger GW170817

    Science.gov (United States)

    Utsumi, Yousuke; Tanaka, Masaomi; Tominaga, Nozomu; Yoshida, Michitoshi; Barway, Sudhanshu; Nagayama, Takahiro; Zenko, Tetsuya; Aoki, Kentaro; Fujiyoshi, Takuya; Furusawa, Hisanori; Kawabata, Koji S.; Koshida, Shintaro; Lee, Chien-Hsiu; Morokuma, Tomoki; Motohara, Kentaro; Nakata, Fumiaki; Ohsawa, Ryou; Ohta, Kouji; Okita, Hirofumi; Tajitsu, Akito; Tanaka, Ichi; Terai, Tsuyoshi; Yasuda, Naoki; Abe, Fumio; Asakura, Yuichiro; Bond, Ian A.; Miyazaki, Shota; Sumi, Takahiro; Tristram, Paul J.; Honda, Satoshi; Itoh, Ryosuke; Itoh, Yoichi; Kawabata, Miho; Morihana, Kumiko; Nagashima, Hiroki; Nakaoka, Tatsuya; Ohshima, Tomohito; Takahashi, Jun; Takayama, Masaki; Aoki, Wako; Baar, Stefan; Doi, Mamoru; Finet, Francois; Kanda, Nobuyuki; Kawai, Nobuyuki; Kim, Ji Hoon; Kuroda, Daisuke; Liu, Wei; Matsubayashi, Kazuya; Murata, Katsuhiro L.; Nagai, Hiroshi; Saito, Tomoki; Saito, Yoshihiko; Sako, Shigeyuki; Sekiguchi, Yuichiro; Tamura, Yoichi; Tanaka, Masayuki; Uemura, Makoto; Yamaguchi, Masaki S.

    2017-12-01

    GW170817 is the first detected gravitational wave source from a neutron star merger. We present the Japanese collaboration for gravitational-wave electro-magnetic (J-GEM) follow-up observations of SSS17a, an electromagnetic counterpart of GW170817. SSS17a shows a 2.5 mag decline in the z band during the period between 1.7 and 7.7 d after the merger. Such a rapid decline is not comparable with supernovae light curves at any epoch. The color of SSS17a also evolves rapidly and becomes redder during later epochs: the z - H color has changed by approximately 2.5 mag during the period between 0.7 and 7.7 d. The rapid evolutions of both the color and the optical brightness are consistent with the expected properties of a kilonova that is powered by the radioactive decay of newly synthesized r-process nuclei. Kilonova models with Lanthanide elements can reproduce the aforementioned observed properties well, which suggests that r-process nucleosynthesis beyond the second peak takes place in SSS17a. However, the absolute magnitude of SSS17a is brighter than the expected brightness of the kilonova models with an ejecta mass of 0.01 M⊙, which suggests a more intense mass ejection (˜0.03 M⊙) or possibly an additional energy source.

  19. Superatom spectroscopy and the electronic state correlation between elements and isoelectronic molecular counterparts.

    Science.gov (United States)

    Peppernick, Samuel J; Gunaratne, K D Dasitha; Castleman, A W

    2010-01-19

    Detailed in the present investigation are results pertaining to the photoelectron spectroscopy of negatively charged atomic ions and their isoelectronic molecular counterparts. Experiments utilizing the photoelectron imaging technique are performed on the negative ions of the group 10 noble metal block (i.e. Ni-, Pd-, and Pt-) of the periodic table at a photon energy of 2.33 eV (532 nm). The accessible electronic transitions, term energies, and orbital angular momentum components of the bound electronic states in the atom are then compared with photoelectron images collected for isoelectronic early transition metal heterogeneous diatomic molecules, M-X- (M = Ti,Zr,W; X = O or C). A superposition principle connecting the spectroscopy between the atomic and molecular species is observed, wherein the electronic structure of the diatomic is observed to mimic that present in the isoelectronic atom. The molecular ions studied in this work, TiO-, ZrO-, and WC- can then be interpreted as possessing superatomic electronic structures reminiscent of the isoelectronic elements appearing on the periodic table, thereby quantifying the superatom concept.

  20. Real-time Automatic Search for Multi-wavelength Counterparts of DWF Transients

    Science.gov (United States)

    Murphy, Christopher; Cucchiara, Antonino; Andreoni, Igor; Cooke, Jeff; Hegarty, Sarah

    2018-01-01

    The Deeper Wider Faster (DWF) survey aims to find and classify the fastest transients in the Universe. DWF utilizes the Dark Energy Camera (DECam), collecting a continuous sequence of 20s images over a 3 square degree field of view.Once an interesting transient is detected during DWF observations, the DWF collaboration has access to several facilities for rapid follow-up in multiple wavelengths (from gamma to radio).An online web tool has been designed to help with real-time visual classification of possible astrophysical transients in data collected by the DWF observing program. The goal of this project is to create a python-based code to improve the classification process by querying several existing archive databases. Given the DWF transient location and search radius, the developed code will extract a list of possible counterparts and all available information (e.g. magnitude, radio fluxes, distance separation).Thanks to this tool, the human classifier can make a quicker decision in order to trigger the collaboration rapid-response resources.

  1. Multiwavelength counterparts of the point sources in the Chandra Source Catalog

    Science.gov (United States)

    Reynolds, Michael; Civano, Francesca Maria; Fabbiano, Giuseppina; D'Abrusco, Raffaele

    2018-01-01

    The most recent release of the Chandra Source Catalog (CSC) version 2.0 comprises more than $\\sim$350,000 point sources, down to fluxes of $\\sim$10$^{-16}$ erg/cm$^2$/s, covering $\\sim$500 deg$^2$ of the sky, making it one of the best available X-ray catalogs to date. There are many reasons to have multiwavelength counterparts for sources, one such reason is that X-ray information alone is not enough to identify the sources and divide them between galactic and extragalactic origin, therefore multiwavelength data associated to each X-ray source is crucial for classification and scientific analysis of the sample. To perform this multiwavelength association, we are going to employ the recently released versatile tool NWAY (Salvato et al. 2017), based on a Bayesian algorithm for cross-matching multiple catalogs. NWAY allows the combination of multiple catalogs at the same time, provides a probability for the matches, even in case of non-detection due to different depth of the matching catalogs, and it can be used by including priors on the nature of the sources (e.g. colors, magnitudes, etc). In this poster, we are presenting the preliminary analysis using the CSC sources above the galactic plane matched to the WISE All-Sky catalog, SDSS, Pan-STARRS and GALEX.

  2. “The Scum of the Earth”? Foreign People Smugglers and Their Local Counterparts in Indonesia

    Directory of Open Access Journals (Sweden)

    Antje Missbach

    2011-01-01

    Full Text Available Since 2008, the number of asylum seekers and refugees trying to reach Australia from Indonesia by boat has increased. With many of them hailing from conflict-ridden countries such as Afghanistan, Iraq and Sri Lanka, most entered Indonesia with short-term tourist visas or fraudulent papers or no documents at all. It is widely known that a significant number of these ‘irregular’ migrants pay various types of brokers (often labelled, accurately or otherwise, ‘human smugglers’ at least at one stage – either to enter the country or to escape it. As a non-signatory to the UN Refugee Convention, Indonesia does not permit local integration. While a substantial part of these migrants are detained in the 13 immigration detention centres scattered around the archipelago, many roam freely, looking for opportunities for onward migration. Due to the restrictive border protection arrangements between Australia and Indonesia and a number of bilateral intelligence measures for deterring ‘unwanted’ migrants, human smugglers have been gradually forced to adapt strategies, routes and prices. According to much of the available data, most human smugglers are not Indonesians but foreigners who have been lingering in Indonesia for many years. This article demonstrates, moreover, that these foreigners depend upon local contacts to successfully carry out their risky business. Most often, the Indonesian counterparts are solely facilitators or handymen, but in a number of cases Indonesian authorities have also been involved in this highly lucrative business.

  3. Holocene reef associated carbonate sediments and their Pleistocene counterparts, Miyako Islands, Ryukyus, southwest of Japan

    Energy Technology Data Exchange (ETDEWEB)

    Tsuji, Y.; Yamamura, T.; Kodato, T.; Sunouchi, H.

    1988-01-01

    Holocene carbonate sedimentary facies distribution, from sea level to shelf slope about 1,000 m in depth, and its relationship to bathymeltry, off Miyako Island, Ryukyus, southwest of Japan were clarified by surveys with sidescan sonar, sparker, uniboom, sea-bottom camera, and sediment sampler. Six facies were recognized using the acoustic data, sample analytical data, and sea-bottom photographs. These are as follows: (A) Reef facies: made mainly of autochthonous hermatypic corals and encrusting algae, 0-60 m deep. (B) Inter-reef muddy facies: consists of very fine sand-size carbonate fraction and line mud, 20-60 m deep surrounded area be reefal relief and islands. (C) Inter-reef and near-reef sandy facies: characterized by tests of shallow benthic foraminifera Calcarina and Marginopora, and Halimeda fragments, 0-90 m deep. (D) Rhodolith and large foraminiferal gravelly shelf facies: contains pebble to cobble-size rhodolith and/and foraminifera Cycloclypeus and Operculina, 60-200 m deep. (E) Bryozoan sandy shelf facies: rich in byrozoan fragments, 80-200 m deep. (F) Shelf slope pelagic foraminiferal facies: dominated by pelagic foraminifera and pteropod molluscan tests, deeper than 200 m. Counterparts of these facies in emerged Pleistocene limestone sequences have been recognized in outcrops and core samples. The results of the marine survey on Holocene deposits made it easy to interpret the Pleistocene depositional environments and sea level changes.

  4. The cocoon emission - an electromagnetic counterpart to gravitational waves from neutron star mergers

    Science.gov (United States)

    Gottlieb, Ore; Nakar, Ehud; Piran, Tsvi

    2018-01-01

    Short gamma-ray bursts are believed to arise from compact binary mergers (either neutron star-neutron star or black hole-neutron star). If so, their jets must penetrate outflows that are ejected during the merger. As a jet crosses the ejecta, it dissipates its energy, producing a hot cocoon that surrounds it. We present here 3D numerical simulations of jet propagation in mergers' outflows, and we calculate the resulting emission. This emission consists of two components: the cooling emission, the leakage of the thermal energy of the hot cocoon, and the cocoon macronova that arises from the radioactive decay of the cocoon's material. This emission gives a brief (∼1 h) blue, wide angle signal. While the parameters of the outflow and jet are uncertain, for the configurations we have considered, the signal is bright (∼-14 to -15 absolute magnitude) and outshines all other predicted ultraviolet-optical signals. The signal is brighter when the jet breakout time is longer, and its peak brightness does not depend strongly on the highly uncertain opacity. A rapid search for such a signal is a promising strategy to detect an electromagnetic merger counterpart. A detected candidate could be then followed by deep infrared searches for the longer but weaker macronova arising from the rest of the ejecta.

  5. Identification of the Infrared Counterpart of SGR 1935+2154 with the Hubble Space Telescope

    Science.gov (United States)

    Levan, Andrew; Kouveliotou, Chryssa; Fruchter, Andrew

    2018-02-01

    We present deep Hubble Space Telescope observations of a new magnetar source, the soft gamma-repeater SGR 1935+2154, discovered by Swift. We obtained three epochs of observations: while the source was active in 2015 March, during a quiescent period in 2015 August, and during a further active phase in 2016 May. Close to the center of the X-ray error region identified by Chandra, we find a faint (F140W(AB) = 25.3) source, which fades by a factor of ∼2 over the course of 5 months between the first two epochs of observations, before rebrightening during the second active period. If this source is indeed the counterpart to SGR 1935+2154, then it is among the faintest yet located for a magnetar. Our observations are spaced over 1.3 years and enable us to place limits on the source velocity of μ = (60 ± 40) km s‑1 kpc‑1 observations on timescales of a decade can hence probe proper motion limits smaller than the velocities observed for the majority of pulsars. The comparison of the optical/IR and X-ray light curves of the source suggests that emission in the two regimes is associated but not directly correlated, offering support for a magnetospheric versus a fallback disk origin.

  6. Understanding Soliton Spectral Tunneling as a Spectral Coupling Effect

    DEFF Research Database (Denmark)

    Guo, Hairun; Wang, Shaofei; Zeng, Xianglong

    2013-01-01

    Soliton eigenstate is found corresponding to a dispersive phase profile under which the soliton phase changes induced by the dispersion and nonlinearity are instantaneously counterbalanced. Much like a waveguide coupler relying on a spatial refractive index profile that supports mode coupling...... between channels, here we suggest that the soliton spectral tunneling effect can be understood supported by a spectral phase coupler. The dispersive wave number in the spectral domain must have a coupler-like symmetric profile for soliton spectral tunneling to occur. We show that such a spectral coupler...... exactly implies phase as well as group-velocity matching between the input soliton and tunneled soliton, namely a soliton phase matching condition. Examples in realistic photonic crystal fibers are also presented....

  7. Tribological responses of the WC/a-C film to sliding against different counterparts in air, water and oil

    Science.gov (United States)

    Sun, Shangqi; Wang, Yongxin; Ye, Yuwei; Liu, Xiang; Lu, Xia; Li, Jinlong

    2017-10-01

    The WC/a-C film prepared using a reactive magnetron sputtering system was investigated. The film structure and properties were characterized, and the friction response mechanism between this film and several counterparts was investigated under different environments. The hardness and surface roughness of the counterpart as well as the match between the properties of the counterpart and the film were identified as factors that play a critical role in the friction behaviour. The environment affected the extent of wear through physical and chemical reactions, and mechanical wear with friction chemical reactions was found to be the major mechanism of influence. This study is of great practical interest, as it will help to extend the service life of WC/a-C films and minimize loss during the initial running-in period.

  8. Search for High-Confidence Blazar Candidates and Their MWL Counterparts in the Fermi-LAT Catalog Using Machine Learning

    Directory of Open Access Journals (Sweden)

    Sabrina Einecke

    2016-08-01

    Full Text Available A large fraction of the gamma-ray sources presented in the Third Fermi-LAT source catalog (3FGL is affiliated with counterparts and source types, but 1010 sources remain unassociated and 573 sources are associated with active galaxies of uncertain type. The purpose of this study is to assign blazar classes to these unassociated and uncertain sources, and to link counterparts to the unassociated. A machine learning algorithm is used for the classification, based on properties extracted from the 3FGL, an infrared and an X-ray catalog. To estimate the reliability of the classification, performance measures are considered through validation techniques. The classification yielded purity values around 90% with efficiency values of roughly 50%. The prediction of high-confidence blazar candidates has been conducted successfully, and the possibility to link counterparts in the same procedure has been proven. These findings confirm the relevance of this novel multiwavelength approach.

  9. SPECTRAL ANALYSIS OF EXCHANGE RATES

    Directory of Open Access Journals (Sweden)

    ALEŠA LOTRIČ DOLINAR

    2013-06-01

    Full Text Available Using spectral analysis is very common in technical areas but rather unusual in economics and finance, where ARIMA and GARCH modeling are much more in use. To show that spectral analysis can be useful in determining hidden periodic components for high-frequency finance data as well, we use the example of foreign exchange rates

  10. Intersection numbers of spectral curves

    CERN Document Server

    Eynard, B

    2011-01-01

    We compute the symplectic invariants of an arbitrary spectral curve with only 1 branchpoint in terms of integrals of characteristic classes in the moduli space of curves. Our formula associates to any spectral curve, a characteristic class, which is determined by the laplace transform of the spectral curve. This is a hint to the key role of Laplace transform in mirror symmetry. When the spectral curve is y=\\sqrt{x}, the formula gives Kontsevich--Witten intersection numbers, when the spectral curve is chosen to be the Lambert function \\exp{x}=y\\exp{-y}, the formula gives the ELSV formula for Hurwitz numbers, and when one chooses the mirror of C^3 with framing f, i.e. \\exp{-x}=\\exp{-yf}(1-\\exp{-y}), the formula gives the topological vertex formula, i.e. the generating function of Gromov-Witten invariants of C^3. In some sense this formula generalizes ELSV formula, and Mumford formula.

  11. Spectral imagery collection experiment

    Science.gov (United States)

    Romano, Joao M.; Rosario, Dalton; Farley, Vincent; Sohr, Brian

    2010-04-01

    The Spectral and Polarimetric Imagery Collection Experiment (SPICE) is a collaborative effort between the US Army ARDEC and ARL for the collection of mid-wave and long-wave infrared imagery using hyperspectral, polarimetric, and broadband sensors. The objective of the program is to collect a comprehensive database of the different modalities over the course of 1 to 2 years to capture sensor performance over a wide variety of adverse weather conditions, diurnal, and seasonal changes inherent to Picatinny's northern New Jersey location. Using the Precision Armament Laboratory (PAL) tower at Picatinny Arsenal, the sensors will autonomously collect the desired data around the clock at different ranges where surrogate 2S3 Self-Propelled Howitzer targets are positioned at different viewing perspectives at 549 and 1280m from the sensor location. The collected database will allow for: 1) Understand of signature variability under the different weather conditions; 2) Development of robust algorithms; 3) Development of new sensors; 4) Evaluation of hyperspectral and polarimetric technologies; and 5) Evaluation of fusing the different sensor modalities. In this paper, we will present the SPICE data collection objectives, the ongoing effort, the sensors that are currently deployed, and how this work will assist researches on the development and evaluation of sensors, algorithms, and fusion applications.

  12. Isospectrals of non-uniform Rayleigh beams with respect to their uniform counterparts

    Science.gov (United States)

    Bhat K, Srivatsa; Ganguli, Ranjan

    2018-02-01

    In this paper, we look for non-uniform Rayleigh beams isospectral to a given uniform Rayleigh beam. Isospectral systems are those that have the same spectral properties, i.e. the same free vibration natural frequencies for a given boundary condition. A transformation is proposed that converts the fourth-order governing differential equation of non-uniform Rayleigh beam into a uniform Rayleigh beam. If the coefficients of the transformed equation match with those of the uniform beam equation, then the non-uniform beam is isospectral to the given uniform beam. The boundary-condition configuration should be preserved under this transformation. We present the constraints under which the boundary configurations will remain unchanged. Frequency equivalence of the non-uniform beams and the uniform beam is confirmed by the finite-element method. For the considered cases, examples of beams having a rectangular cross section are presented to show the application of our analysis.

  13. Community Stroke Rehabilitation: How Do Rural Residents Fare Compared With Their Urban Counterparts?

    Science.gov (United States)

    Allen, Laura; McIntyre, Amanda; Janzen, Shannon; Richardson, Marina; Meyer, Matthew; Ure, David; Teasell, Robert

    2016-01-01

    Rural living has been demonstrated to have an effect on a person's overall health status, and rural residing individuals often have decreased access to health and specialized rehabilitation services. The aim of this study was to determine if there are differences in recovery from stroke between urban and rural-dwelling stroke survivors accessing an in-home, community-based, interdisciplinary, stroke rehabilitation program. Data from a cohort of 1222 stroke survivors receiving care from the Community Stroke Rehabilitation Teams between January 2009 and June 2013 was analyzed. This program delivers stroke rehabilitation care directly in a person's home and community. Functional and psychosocial outcomes were evaluated at baseline, discharge, and six -month follow-up. A series of multiple linear regression analyses was performed to determine if rural versus urban status was a significant predictor of discharge and 6-month health outcomes. The mean age of the rural cohort was 68.8 (±13.1) years (53.6% male), and the urban cohort was 68.4 (±13.0) years (44.8% male). A total of 278 (35.4%) individuals were classified as living in a rural area using the Rurality Index for Ontario. In multivariate linear regression analysis, no significant differences on the Functional Independence Measure, the Stroke Impact Scale, the Hospital Anxiety and Depression Scale, or the Reintegration to Normal Living Index were found between urban and rural cohorts. When provided with access to a home-based, specialized stroke rehabilitation program, rural dwelling stroke survivors make and maintain functional gains comparable to their urban-living counterparts.

  14. Optical Counterparts for Low-Luminosity X-ray Sources in Omega Centauri

    Science.gov (United States)

    Cool, Adrienne

    2002-07-01

    We propose to use narrow-band HAlpha imaging with ACS to search for the optical counterparts of low-luminosity X-ray sources {Lx 2 x 10^30 - 5 x 10^32 erg/s} in the globular cluster Omega Centauri. With 9 WFC fields, we will cover the inner two core radii of the cluster, and encompass about 90 of the faint sources we have identified with Chandra. Approximately 30-50 of these sources should be cluster members, the remainder being mostly background galaxies plus a smaller number of foreground stars. This large population of low-Lx cluster X-ray sources is second only to the more than 100 faint sources recently discovered in 47 Tuc with Chandra {Grindlay et al. 2001a}, which have been identified as a mixture of cataclysmic variables, quiescent low-mass X-ray binaries, millisecond pulsars, and coronally active main-sequence binaries. Our Cycle 6 WFPC2 program successfully identified 2 of the 3 then-known faint X-ray sources in the core of Omega Cen using H-alpha imaging. We now propose to expand the areal coverage by a factor of about 18 to encompass the much larger number of sources that have since been discovered with Chandra. The extreme crowding in the central regions of Omega Cen requires the resolution of HST to obtain optical IDs. These identifications are key to making meaningful comparisons between the populations of faint X-ray sources in different clusters, in an effort to understand their origins and role in cluster dynamics.

  15. Genomic variations in the counterpart normal controls of lung squamous cell carcinomas.

    Science.gov (United States)

    Qu, Liwei; Zhou, Bo; Wang, Guizhen; Zhou, Guangbiao

    2017-11-28

    Lung squamous cell carcinoma (LUSC) causes approximately 400 000 deaths each year worldwide. The occurrence of LUSC is attributed to exposure to cigarette smoke, which induces the development of numerous genomic abnormalities. However, few studies have investigated the genomic variations that occur only in normal tissues that have been similarly exposed to tobacco smoke as tumor tissues. In this study, we sequenced the whole genomes of three normal lung tissue samples and their paired adjacent squamous cell carcinomas.We then called genomic variations specific to the normal lung tissues through filtering the genomic sequence of the normal lung tissues against that of the paired tumors, the reference human genome, the dbSNP138 common germline variants, and the variations derived from sequencing artifacts. To expand these observations, the whole exome sequences of 478 counterpart normal controls (CNCs) and paired LUSCs of The Cancer Genome Atlas (TCGA) dataset were analyzed. Sixteen genomic variations were called in the three normal lung tissues. These variations were confirmed by Sanger capillary sequencing. A mean of 0.5661 exonic variations/Mb and 7.7887 altered genes per sample were identified in the CNC genome sequences of TCGA. In these CNCs, C:G→T:A transitions, which are the genomic signatures of tobacco carcinogen N-methyl-N-nitro-N-nitrosoguanidine, were the predominant nucleotide changes. Twenty five genes in CNCs had a variation rate that exceeded 2%, including ARSD (18.62%), MUC4 (8.79%), and RBMX (7.11%). CNC variations in CTAGE5 and USP17L7 were associated with the poor prognosis of patients with LUSC. Our results uncovered previously unreported genomic variations in CNCs, rather than LUSCs, that may be involved in the development of LUSC.

  16. Binary Black Hole Mergers within the LIGO Horizon: Statistical Properties and prospects for detecting Electromagnetic Counterparts

    Science.gov (United States)

    Perna, Rosalba; Chruslinska, Martyna; Corsi, Alessandra; Belczynski, Krzysztof

    2018-03-01

    Binary black holes (BBHs) are one of the endpoints of isolated binary evolution, and their mergers a leading channel for gravitational wave events. Here, using the evolutionary code STARTRACK, we study the statistical properties of the BBH population from isolated binary evolution for a range of progenitor star metallicities and BH natal kicks. We compute the mass function and the distribution of the primary BH spin a as a result of mass accretion during the binary evolution, and find that this is not an efficient process to spin up BHs, producing an increase by at most a ˜ 0.2-0.3 for very low natal BH spins. We further compute the distribution of merger sites within the host galaxy, after tracking the motion of the binaries in the potentials of a massive spiral, a massive elliptical, and a dwarf galaxy. We find that a fraction of 70-90% of mergers in massive galaxies and of 40-60% in dwarfs (range mostly sensitive to the natal kicks) is expected to occur inside of their hosts. The number density distribution at the merger sites further allows us to estimate the broadband luminosity distribution that BBH mergers would produce, if associated with a kinetic energy release in an outflow, which, as a reference, we assume at the level inferred for the Fermi GBM counterpart to GW150914, with the understanding that current limits from the O1 and O2 runs would require such emission to be produced within a jet of angular size within ≲ 50°.

  17. Life-cycle Analysis of Bioproducts and Their Conventional Counterparts in GREET

    Energy Technology Data Exchange (ETDEWEB)

    Dunn, Jennifer B. [Argonne National Lab. (ANL), Argonne, IL (United States); Adom, Felix [Argonne National Lab. (ANL), Argonne, IL (United States); Sather, Norm [Argonne National Lab. (ANL), Argonne, IL (United States); Han, Jeongwoo [Argonne National Lab. (ANL), Argonne, IL (United States); Snyder, Seth [Argonne National Lab. (ANL), Argonne, IL (United States); He, Chang [Northwestern Univ., Evanston, IL (United States); Gong, Jian [Northwestern Univ., Evanston, IL (United States); Yue, Dajun [Northwestern Univ., Evanston, IL (United States); You, Fengqi [Northwestern Univ., Evanston, IL (United States)

    2015-09-01

    To further expand upon the literature in this field and to develop a platform for bioproduct LCA, we developed LCA results for ten bioproducts produced either from algal glycerol or from corn stover-derived sugars. We used Argonne National Laboratory’s Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREETTM) model as the platform for this study. The data and calculations reported herein are available to GREET users in a bioproducts module included in the fall 2015 GREET release. This report documents our approach to this analysis and the results. In Chapter 2, we review the process we underwent to select the bioproducts for analysis based on market and technology readiness criteria. In Chapter 3, we review key parameters for production of the two feedstocks we considered: corn stover and algae. Given the lack of publicly available information about the production of bioproducts, which is caused in large part by the emerging nature of the industry, we developed Aspen Plus® simulations of the processes that could be used to produce each bioproduct. From these simulations, we extracted the energy and material flows of these processes, which were important inputs to the GREET bioproducts module. Chapter 4 provides the details of these Aspen Plus simulations. It is important to compare the LCA results for bioproducts to those for their petroleum counterparts. We therefore also developed material and energy flow data for conventional products based mostly on the literature. These data are described in Chapter 5 and are also included in the GREET bioproducts module. In Chapter 6, we present results from this analysis and examine areas for refinement and future research.

  18. Multiband counterparts of two eclipsing ultraluminous X-ray sources in M 51

    Science.gov (United States)

    Urquhart, R.; Soria, R.; Johnston, H. M.; Pakull, M. W.; Motch, C.; Schwope, A.; Miller-Jones, J. C. A.; Anderson, G. E.

    2018-04-01

    We present the discovery and interpretation of ionized nebulae around two ultraluminous X-ray sources in M 51; both sources share the rare property of showing X-ray eclipses by their companion stars and are therefore prime targets for follow-up studies. Using archival Hubble Space Telescope images, we found an elongated, 100-pc-long emission-line structure associated with one X-ray source (CXOM51 J132940.0+471237; ULX-1 for simplicity), and a more circular, ionized nebula at the location of the second source (CXOM51 J132939.5+471244; ULX-2 for simplicity). We observed both nebulae with the Large Binocular Telescope's Multi-Object Double Spectrograph. From our analysis of the optical spectra, we argue that the gas in the ULX-1 bubble is shock-ionized, consistent with the effect of a jet with a kinetic power of ≈2 × 1039 erg s-1. Additional X-ray photoionization may also be present, to explain the strength of high-ionization lines such as He II λ4686 and [Ne V] λ3426. On the other hand, the emission lines from the ULX-2 bubble are typical for photoionization by normal O stars suggesting that the nebula is actually an H II region not physically related to the ULX but is simply a chance alignment. From archival Very Large Array data, we also detect spatially extended, steep-spectrum radio emission at the location of the ULX-1 bubble (consistent with its jet origin), but no radio counterpart for ULX-2 (consistent with the lack of shock-ionized gas around that source).

  19. Refractive predictability of a 3-piece intraocular lens platform versus its 1-piece counterpart.

    Science.gov (United States)

    Mednick, Zale D; Varma, Devesh K; Campos-Möller, Xavier; Ahmed, Iqbal Ike K

    2017-04-01

    To compare the refractive outcomes of a 3-piece acrylic intraocular lens (IOL) with its 1-piece counterpart after phacoemulsification with in-the-bag implantation. Retrospective chart review. One-hundred twenty-six eyes of 95 patients were analyzed in the study, including 60 eyes of 43 patients receiving a 3-piece IOL and 66 eyes of 52 patients receiving a 1-piece IOL. Randomized chart review of all patients who underwent uncomplicated phacoemulsification with in-the-bag IOL implantation with either a 3-piece hydrophobic acrylic IOL (Tecnis ZA9003) or a 1-piece hydrophobic acrylic IOL (Tecnis ZCB00) between 2006 and 2014 in a tertiary ophthalmology care centre in Mississauga, Ontario. Preoperative visual acuity and refraction, anterior chamber depth, axial length, IOL design and power, predicted refraction, postoperative visual acuity, and refraction were recorded. Mean absolute error was 0.40 ± 0.27 in the ZA9003 group and 0.39 ± 0.35 in the ZCB00 group, with no statistically significant difference between the 2 IOLs (p = 0.86). Mean arithmetic error was 0.11 ± 0.47 D in the ZA9003 group and 0.01 ± 0.47 D in the ZCB00 group (p = 0.019). In the ZA9003 group, 23 (38%), 42 (70%), and 52 (87%) of 60 eyes were within 0.25, 0.50, and 0.75 D, respectively, of predicted postoperative refraction. In the ZCB00 group, 32 (48%), 46 (70%), and 56 (85%) of 66 eyes were within 0.25, 0.50, and 0.75 D, respectively, of predicted postoperative refraction (p = 0.2836, p = 1.00, p = 0.8044). The ZA9003 and the ZCB00 have similar mean absolute error and thus appear to have similar refractive predictability. Copyright © 2017 Canadian Ophthalmological Society. Published by Elsevier Inc. All rights reserved.

  20. Independent introductions and admixtures have contributed to adaptation of European maize and its American counterparts.

    Directory of Open Access Journals (Sweden)

    Jean-Tristan Brandenburg

    2017-03-01

    Full Text Available Through the local selection of landraces, humans have guided the adaptation of crops to a vast range of climatic and ecological conditions. This is particularly true of maize, which was domesticated in a restricted area of Mexico but now displays one of the broadest cultivated ranges worldwide. Here, we sequenced 67 genomes with an average sequencing depth of 18x to document routes of introduction, admixture and selective history of European maize and its American counterparts. To avoid the confounding effects of recent breeding, we targeted germplasm (lines directly derived from landraces. Among our lines, we discovered 22,294,769 SNPs and between 0.9% to 4.1% residual heterozygosity. Using a segmentation method, we identified 6,978 segments of unexpectedly high rate of heterozygosity. These segments point to genes potentially involved in inbreeding depression, and to a lesser extent to the presence of structural variants. Genetic structuring and inferences of historical splits revealed 5 genetic groups and two independent European introductions, with modest bottleneck signatures. Our results further revealed admixtures between distinct sources that have contributed to the establishment of 3 groups at intermediate latitudes in North America and Europe. We combined differentiation- and diversity-based statistics to identify both genes and gene networks displaying strong signals of selection. These include genes/gene networks involved in flowering time, drought and cold tolerance, plant defense and starch properties. Overall, our results provide novel insights into the evolutionary history of European maize and highlight a major role of admixture in environmental adaptation, paralleling recent findings in humans.

  1. Reversal of functional disorders by aspiration, expiration and cough reflexes and their voluntary counterparts

    Directory of Open Access Journals (Sweden)

    Zoltan eTomori

    2012-12-01

    Full Text Available Agonal gasping provoked by asphyxia can save ~15% of mammals even from untreated ventricular fibrillation, but it fails to revive infants with sudden infant death syndrome. Our systematic study of airway reflexes in cats and other animals indicated that in addition to cough, there are 2 distinct airway reflexes that may contribute to auto-resuscitation. Gasp- and sniff-like spasmodic inspirations can be elicited by nasopharyngeal stimulation, strongly activating the brainstem generator for inspiration, which is also involved in the control of gasping. This aspiration reflex (AspR is characterized by spasmodic inspiration without subsequent active expiration and can be elicited during agonal gasping, caused by brainstem trans-sections in cats. Stimulation of the larynx can activate the generator for expiration to evoke the expiration reflex, manifesting with prompt expiration without preceding inspiration. Stimulation of the oro-pharynx and lower airways provokes the cough reflex which results from activating of both generators. The powerful potential of the AspR resembling auto-resuscitation by gasping can influence the control mechanisms of vital functions, mediating reversal of various functional disorders.The AspR in cats interrupted hypoxic apnea, laryngo- and bronchospasm, apneusis and even transient asphyxic coma, and can normalize various hypo- and hyper-functional disorders. Introduction of a nasogastric catheter evoked similar spasmodic inspirations in premature infants and interrupted hiccough attacks in adults. Coughing on demand can prevent anaphylactic shock and resuscitate the pertinent subject. Sniff representing nasal inspiratory pressure and maximal inspiratory and expiratory pressures are voluntary counterparts of airway reflexes, and are useful for diagnosis and therapy of various cardio-respiratory and neuromuscular disorders.

  2. Energetic particle counterparts for geomagnetic pulsations of Pc1 and IPDP types

    Directory of Open Access Journals (Sweden)

    T. A. Yahnina

    2003-12-01

    Full Text Available Using the low-altitude NOAA satellite particle data, we study two kinds of localised variations of energetic proton fluxes at low altitude within the anisotropic zone equatorward of the isotropy boundary. These flux variation types have a common feature, i.e. the presence of precipitating protons measured by the MEPED instrument at energies more than 30 keV, but they are distinguished by the fact of the presence or absence of the lower-energy component as measured by the TED detector on board the NOAA satellite. The localised proton precipitating without a low-energy component occurs mostly in the morning-day sector, during quiet geomagnetic conditions, without substorm injections at geosynchronous orbit, and without any signatures of plasmaspheric plasma expansion to the geosynchronous distance. This precipitation pattern closely correlates with ground-based observations of continuous narrow-band Pc1 pulsations in the frequency range 0.1–2 Hz (hereafter Pc1. The precipitation pattern containing the low energy component occurs mostly in the evening sector, under disturbed geomagnetic conditions, and in association with energetic proton injections and significant increases of cold plasma density at geosynchronous orbit. This precipitation pattern is associated with geomagnetic pulsations called Intervals of Pulsations with Diminishing Periods (IPDP, but some minor part of the events is also related to narrow-band Pc1. Both Pc1 and IPDP pulsations are believed to be the electromagnetic ion-cyclotron waves generated by the ion-cyclotron instability in the equatorial plane. These waves scatter energetic protons in pitch angles, so we conclude that the precipitation patterns studied here are the particle counterparts of the ion-cyclotron waves.Key words. Ionosphere (particle precipitation – Magnetospheric physics (energetic particles, precipitating – Space plasma physics (wave-particle interactions

  3. Molecular Characteristics of Malignant Ovarian Germ Cell Tumors and Comparison With Testicular Counterparts: Implications for Pathogenesis

    Science.gov (United States)

    Kraggerud, Sigrid Marie; Hoei-Hansen, Christina E.; Alagaratnam, Sharmini; Skotheim, Rolf I.; Abeler, Vera M.

    2013-01-01

    This review focuses on the molecular characteristics and development of rare malignant ovarian germ cell tumors (mOGCTs). We provide an overview of the genomic aberrations assessed by ploidy, cytogenetic banding, and comparative genomic hybridization. We summarize and discuss the transcriptome profiles of mRNA and microRNA (miRNA), and biomarkers (DNA methylation, gene mutation, individual protein expression) for each mOGCT histological subtype. Parallels between the origin of mOGCT and their male counterpart testicular GCT (TGCT) are discussed from the perspective of germ cell development, endocrinological influences, and pathogenesis, as is the GCT origin in patients with disorders of sex development. Integrated molecular profiles of the 3 main histological subtypes, dysgerminoma (DG), yolk sac tumor (YST), and immature teratoma (IT), are presented. DGs show genomic aberrations comparable to TGCT. In contrast, the genome profiles of YST and IT are different both from each other and from DG/TGCT. Differences between DG and YST are underlined by their miRNA/mRNA expression patterns, suggesting preferential involvement of the WNT/β-catenin and TGF-β/bone morphogenetic protein signaling pathways among YSTs. Characteristic protein expression patterns are observed in DG, YST and IT. We propose that mOGCT develop through different developmental pathways, including one that is likely shared with TGCT and involves insufficient sexual differentiation of the germ cell niche. The molecular features of the mOGCTs underline their similarity to pluripotent precursor cells (primordial germ cells, PGCs) and other stem cells. This similarity combined with the process of ovary development, explain why mOGCTs present so early in life, and with greater histological complexity, than most somatic solid tumors. PMID:23575763

  4. ULTRAVIOLET RAMAN SPECTRAL SIGNATURE ACQUISITION: UV RAMAN SPECTRAL FINGERPRINTS.

    Energy Technology Data Exchange (ETDEWEB)

    SEDLACEK,III, A.J.FINFROCK,C.

    2002-09-01

    As a member of the science-support part of the ITT-lead LISA development program, BNL is tasked with the acquisition of UV Raman spectral fingerprints and associated scattering cross-sections for those chemicals-of-interest to the program's sponsor. In support of this role, the present report contains the first installment of UV Raman spectral fingerprint data on the initial subset of chemicals. Because of the unique nature associated with the acquisition of spectral fingerprints for use in spectral pattern matching algorithms (i.e., CLS, PLS, ANN) great care has been undertaken to maximize the signal-to-noise and to minimize unnecessary spectral subtractions, in an effort to provide the highest quality spectral fingerprints. This report is divided into 4 sections. The first is an Experimental section that outlines how the Raman spectra are performed. This is then followed by a section on Sample Handling. Following this, the spectral fingerprints are presented in the Results section where the data reduction process is outlined. Finally, a Photographs section is included.

  5. The second Herschel-ATLAS Data Release - III. Optical and near-infrared counterparts in the North Galactic Plane field

    Science.gov (United States)

    Furlanetto, C.; Dye, S.; Bourne, N.; Maddox, S.; Dunne, L.; Eales, S.; Valiante, E.; Smith, M. W.; Smith, D. J. B.; Ivison, R. J.; Ibar, E.

    2018-05-01

    This paper forms part of the second major public data release of the Herschel Astrophysical Terahertz Large Area Survey (H-ATLAS). In this work, we describe the identification of optical and near-infrared counterparts to the submillimetre detected sources in the 177 deg2 North Galactic Plane (NGP) field. We used the likelihood ratio method to identify counterparts in the Sloan Digital Sky Survey and in the United Kingdom InfraRed Telescope Imaging Deep Sky Survey within a search radius of 10 arcsec of the H-ATLAS sources with a 4σ detection at 250 μm. We obtained reliable (R ≥ 0.8) optical counterparts with r performance of the likelihood ratio method to identify optical and near-infrared counterparts taking into account the depth and area of both input catalogues. Using catalogues with the same surface density of objects in the overlapping ˜25 deg2 area, we obtained that the reliable fraction in the near-infrared (54.8 per cent) is significantly higher than in the optical (36.4 per cent). Finally, using deep radio data which covers a small region of the NGP field, we found that 80-90 per cent of our reliable identifications are correct.

  6. Search for the NIR counterpart to GRB130807A/SWIFTJ1759.2-2736 in quiescence

    NARCIS (Netherlands)

    Greiss, S.; Steeghs, D.; Jonker, P.G.; Maccarone, T.; Torres, M.A.P.; Heinke, C.; Wijnands, R.

    2013-01-01

    In order to search for the counterpart of the transient source SWIFTJ1759.2-2736 (Atel #5268), we investigated near-infrared (NIR) data of the Galactic Bulge region obtained as part of the VVV survey (Minniti et al. 2010, New Astronomy, Volume 15, 433). The observations took place while the source

  7. The Effect of Counterpart Material on the Sliding Wear of TiAlN Coatings Deposited by Reactive Cathodic Pulverization

    Directory of Open Access Journals (Sweden)

    Michell Felipe Cano Ordoñez

    2015-11-01

    Full Text Available This work aims to study the effect of the counterpart materials (100Cr6, Al2O3 and WC-Co on the tribological properties of TiAlN thin films deposited on AISI H13 steel substrate by reactive magnetron co-sputtering. The structural characterization of the TiAlN films, performed by X-ray diffraction, showed (220 textured fcc crystalline structure. The values of hardness and elastic modulus obtained by nanoindentation were 27 GPa and 420 GPa, respectively, which resulted in films with a relatively high resistance to plastic deformation. Ball-on-disk sliding tests were performed using normal loads of 1 N and 3 N, and 0.10 m/s of tangential velocity. The wear coefficient of the films was determined by measuring the worn area using profilometry every 1000 cycles. The mechanical properties and the chemical stability of the counterpart material, debris formation and the contact stress influences the friction and the wear behavior of the studied tribosystems. Increasing the hardness of the counterpart decreases the coefficient of friction (COF due to lower counterpart material transference and tribofilm formation, which is able to support the contact pressure. High shear stress concentration at the coating/substrate interface was reported for higher load promoting failure of the film-substrate system for all tribopairs

  8. Subaru/FOCAS Optical Spectroscopy for a possible IceCube-170922A counterpart TXS 0506+056

    Science.gov (United States)

    Morokuma, Tomoki; Tanaka, Yasuyuki T.; Ohta, Kouji; Matsuoka, Yoshiki; Yamashita, Takuji; Kato, Nanako

    2017-10-01

    We performed optical spectroscopic observations on September 30 and October 1, 2017 (UT) with the 8.2-m Subaru telescope and Faint Object Camera and Spectrograph (FOCAS) for TXS 0506+056 which is a possible counterpart to the IceCube-170922A high-energy neutrino event (Tanaka et al. 2017, ATel #10791).

  9. Coronal type III radio bursts and their X-ray flare and interplanetary type III counterparts

    Science.gov (United States)

    Reid, Hamish A. S.; Vilmer, Nicole

    2017-01-01

    Context. Type III bursts and hard X-rays are both produced by flare energetic electron beams. The link between both emissions has been investigated in many previous studies, but no statistical studies have compared both coronal and interplanetary type III bursts with X-ray flares. Aims: Using events where the coronal radio emission above 100 MHz is exclusively from type III bursts, we revisited some long-standing questions regarding the relation between type III bursts and X-ray flares: Do all coronal type III bursts have X-ray counterparts? What correlation, if any, occurs between radio and X-ray intensities? What X-ray and radio signatures above 100 MHz occur in connection with interplanetary type III bursts below 14 MHz? Methods: We analysed ten years of data from 2002 to 2011 starting with a selection of coronal type III bursts above 100 MHz. We used X-ray flare information from RHESSI >6 keV to make a list of 321 events that have associated type III bursts and X-ray flares, encompassing at least 28% of the initial sample of type III events. We then examined the timings, intensities, associated GOES class, and whether there was an associated interplanetary radio signature in both radio and X-rays. Results: For our 321 events with radio and X-ray signatures, the X-ray emission at 6 keV usually lasted much longer than the groups of type III bursts at frequencies >100 MHz. The selected events were mostly associated with GOES B and C class flares. A weak correlation was found between the type III radio flux at frequencies below 327 MHz and the X-ray intensity at 25-50 keV, with an absence of events at high X-ray intensity and low type III radio flux. The weakness of the correlation is related to the coherent emission mechanism of radio type IIIs which can produce high radio fluxes by low density electron beams. Interplanetary type III bursts (103 SFU), relating to electron beams with more energetic electrons above 25 keV and events where magnetic flux tubes extend

  10. Post-test analysis of the ROSA/LSTF and PKL counterpart test

    Energy Technology Data Exchange (ETDEWEB)

    Carlos, S., E-mail: scarlos@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Querol, A., E-mail: anquevi@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camí de Vera, 14, València (Spain); Gallardo, S., E-mail: sergalbe@iqn.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); Instituto de Seguridad Industrial, Radiofísica y Medioambiental, Universitat Politècnica de València, Camí de Vera, 14, València (Spain); Sanchez-Saez, F., E-mail: frasansa@etsii.upv.es [Departament d’Enginyeria Química i Nuclear, Universitat Politècnica de València, Camí de Vera, 14, València Spain (Spain); and others

    2016-02-15

    Highlights: • TRACE modelization for PKL and ROSA/LSTF installations. • Secondary-side depressurization as accident management action. • CET vs PCT relation. • Analysis of differences in the vessel models. - Abstract: Experimental facilities are scaled models of commercial nuclear power plants, and are of great importance to improve nuclear power plants safety. Thus, the results obtained in the experiments undertaken in such facilities are essential to develop and improve the models implemented in the thermal-hydraulic codes, which are used in safety analysis. The experiments and inter-comparisons of the simulated results are usually performed in the frame of international programmes in which different groups of several countries simulate the behaviour of the plant under the accidental conditions established, using different codes and models. The results obtained are compared and studied to improve the knowledge on codes performance and nuclear safety. Thus, the Nuclear Energy Agency (NEA), in the nuclear safety work area, auspices several programmes which involve experiments in different experimental facilities. Among the experiments proposed in NEA programmes, one on them consisted of performing a counterpart test between ROSA/LSTF and PKL facilities, with the main objective of determining the effectiveness of late accident management actions in a small break loss of coolant accident (SBLOCA). This study was proposed as a result of the conclusion obtained by the NEA Working Group on the Analysis and Management of Accidents, which analyzed different installations and observed differences in the measurements of core exit temperature (CET) and maximum peak cladding temperature (PCT). In particular, the transient consists of a small break loss of coolant accident (SBLOCA) in a hot leg with additional failure of safety systems but with accident management measures (AM), consisting of a fast secondary-side depressurization, activated by the CET. The paper

  11. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r-process Nucleosynthesis with Gemini-South

    Science.gov (United States)

    Chornock, R.; Berger, E.; Kasen, D.; Cowperthwaite, P. S.; Nicholl, M.; Villar, V. A.; Alexander, K. D.; Blanchard, P. K.; Eftekhari, T.; Fong, W.; Margutti, R.; Williams, P. K. G.; Annis, J.; Brout, D.; Brown, D. A.; Chen, H.-Y.; Drout, M. R.; Farr, B.; Foley, R. J.; Frieman, J. A.; Fryer, C. L.; Herner, K.; Holz, D. E.; Kessler, R.; Matheson, T.; Metzger, B. D.; Quataert, E.; Rest, A.; Sako, M.; Scolnic, D. M.; Smith, N.; Soares-Santos, M.

    2017-10-01

    We present a near-infrared spectral sequence of the electromagnetic counterpart to the binary neutron star merger GW170817 detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo. Our data set comprises seven epochs of J+H spectra taken with FLAMINGOS-2 on Gemini-South between 1.5 and 10.5 days after the merger. In the initial epoch, the spectrum is dominated by a smooth blue continuum due to a high-velocity, lanthanide-poor blue kilonova component. Starting the following night, all of the subsequent spectra instead show features that are similar to those predicted in model spectra of material with a high concentration of lanthanides, including spectral peaks near 1.07 and 1.55 μm. Our fiducial model with 0.04 M ⊙ of ejecta, an ejection velocity of v = 0.1c, and a lanthanide concentration of X lan = 10-2 provides a good match to the spectra taken in the first five days, although it over-predicts the late-time fluxes. We also explore models with multiple fitting components, in each case finding that a significant abundance of lanthanide elements is necessary to match the broad spectral peaks that we observe starting at 2.5 days after the merger. These data provide direct evidence that binary neutron star mergers are significant production sites of even the heaviest r-process elements.

  12. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. IV. Detection of Near-infrared Signatures of r -process Nucleosynthesis with Gemini-South

    Energy Technology Data Exchange (ETDEWEB)

    Chornock, R. [Astrophysical Institute, Department of Physics and Astronomy, 251B Clippinger Lab, Ohio University, Athens, OH 45701 (United States); Berger, E.; Cowperthwaite, P. S.; Nicholl, M.; Villar, V. A.; Alexander, K. D.; Blanchard, P. K.; Eftekhari, T.; Williams, P. K. G. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Kasen, D. [Departments of Physics and Astronomy, and Theoretical Astrophysics Center, University of California, Berkeley, CA 94720-7300 (United States); Fong, W.; Margutti, R. [Center for Interdisciplinary Exploration and Research in Astrophysics (CIERA) and Department of Physics and Astronomy, Northwestern University, Evanston, IL 60208 (United States); Annis, J.; Frieman, J. A. [Fermi National Accelerator Laboratory, P.O. Box 500, Batavia, IL 60510 (United States); Brout, D. [Department of Physics and Astronomy, University of Pennsylvania, Philadelphia, PA 19104 (United States); Brown, D. A. [Department of Physics, Syracuse University, Syracuse NY 13224 (United States); Chen, H.-Y. [Department of Astronomy and Astrophysics, University of Chicago, Chicago, IL 60637 (United States); Drout, M. R. [The Observatories of the Carnegie Institution for Science, 813 Santa Barbara Street, Pasadena, CA 91101 (United States); Farr, B. [Department of Physics, University of Oregon, Eugene, OR 97403 (United States); Foley, R. J., E-mail: chornock@ohio.edu [Department of Astronomy and Astrophysics, University of California, Santa Cruz, CA 95064 (United States); and others

    2017-10-20

    We present a near-infrared spectral sequence of the electromagnetic counterpart to the binary neutron star merger GW170817 detected by Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo. Our data set comprises seven epochs of J + H spectra taken with FLAMINGOS-2 on Gemini-South between 1.5 and 10.5 days after the merger. In the initial epoch, the spectrum is dominated by a smooth blue continuum due to a high-velocity, lanthanide-poor blue kilonova component. Starting the following night, all of the subsequent spectra instead show features that are similar to those predicted in model spectra of material with a high concentration of lanthanides, including spectral peaks near 1.07 and 1.55 μ m. Our fiducial model with 0.04 M {sub ⊙} of ejecta, an ejection velocity of v = 0.1 c , and a lanthanide concentration of X {sub lan} = 10{sup −2} provides a good match to the spectra taken in the first five days, although it over-predicts the late-time fluxes. We also explore models with multiple fitting components, in each case finding that a significant abundance of lanthanide elements is necessary to match the broad spectral peaks that we observe starting at 2.5 days after the merger. These data provide direct evidence that binary neutron star mergers are significant production sites of even the heaviest r -process elements.

  13. Infrared Spectra of Protonated Pyrene and Its Neutral Counterpart in Solid para-Hydrogen.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Yu-Jong; Lee, Yuan-Pern

    2013-06-20

    Protonated polycyclic aromatic hydrocarbons (H(+)PAHs) have been reported to have infrared (IR) bands at wavenumbers near those of unidentified infrared (UIR) emission bands from interstellar objects. We produced 1-C16H11(+) and 1-C16H11 upon electron bombardment during matrix deposition of p-H2 containing pyrene (C16H10) in a small proportion. Intensities of absorption features of 1-C16H11(+) decreased after the matrix was maintained in darkness or irradiated with light at 365 nm, whereas those of 1-C16H11 increased. The observed line wavenumbers and relative intensities of 1-C16H11(+) and 1-C16H11 agree satisfactorily with the scaled vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. Our method, being relatively clean with negligible fragmentation, is applicable to larger H(+)PAH; it has the advantages of producing excellent IR spectra covering a broad spectral range with narrow lines and accurate intensities, so that structural identification among various isomers is feasible.

  14. Formation and infrared absorption of protonated naphthalenes (1-C10H9+ and 2-C10H9+) and their neutral counterparts in solid para-hydrogen.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Yu-Jong; Lee, Yuan-Pern

    2013-02-14

    Protonated naphthalene (C(10)H(9)(+)) and its neutral counterparts (hydronaphthyl radicals, C(10)H(9)) are important intermediates in the reactions of aromatic compounds and in understanding the unidentified infrared (IR) emissions from interstellar media. We report the IR spectra of 1-C(10)H(9)(+), 2-C(10)H(9)(+), 1-C(10)H(9), and 2-C(10)H(9) trapped in solid para-hydrogen (p-H(2)); the latter three are new. These species were produced upon electron bombardment of a mixture of naphthalene (C(10)H(8)) and p-H(2) during matrix deposition. The intensities of IR features of 1-C(10)H(9)(+) decreased after the matrix was maintained in darkness for 19 h, whereas those of 1-C(10)H(9) and 2-C(10)H(9) increased. Irradiation of this matrix sample with light at 365 nm diminished lines of 1-C(10)H(9)(+) and 2-C(10)H(9) and enhanced lines of 1-C(10)H(9) and 2-C(10)H(9)(+); the latter species was unstable and converted to 1-C(10)H(9)(+) in less than 30 min and 2-C(10)H(9) was converted to 1-C(10)H(9) at 365 nm. Observed wavenumbers and relative intensities of these species agree satisfactorily with the anharmonic vibrational wavenumbers and IR intensities predicted with the B3PW91/6-311++G(2d,2p) method. Compared with spectra recorded previously with IR photodissociation of Ar-tagged C(10)H(9)(+) or IR multiphoton dissociation of C(10)H(9)(+), our method has the advantages of producing high-resolution IR spectra with a wide spectral coverage, true IR intensity and excellent ratio of signal to noise; both protonated species and their neutral counterparts are produced with little interference from other fragments. With these advantages, the IR spectra of 1-C(10)H(9)(+), 2-C(10)H(9)(+), 1-C(10)H(9), and 2-C(10)H(9) are here clearly characterized.

  15. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models

    Science.gov (United States)

    Cowperthwaite, P. S.; Berger, E.; Villar, V. A.; Metzger, B. D.; Nicholl, M.; Chornock, R.; Blanchard, P. K.; Fong, W.; Margutti, R.; Soares-Santos, M.; Alexander, K. D.; Allam, S.; Annis, J.; Brout, D.; Brown, D. A.; Butler, R. E.; Chen, H.-Y.; Diehl, H. T.; Doctor, Z.; Drout, M. R.; Eftekhari, T.; Farr, B.; Finley, D. A.; Foley, R. J.; Frieman, J. A.; Fryer, C. L.; García-Bellido, J.; Gill, M. S. S.; Guillochon, J.; Herner, K.; Holz, D. E.; Kasen, D.; Kessler, R.; Marriner, J.; Matheson, T.; Neilsen, E. H., Jr.; Quataert, E.; Palmese, A.; Rest, A.; Sako, M.; Scolnic, D. M.; Smith, N.; Tucker, D. L.; Williams, P. K. G.; Balbinot, E.; Carlin, J. L.; Cook, E. R.; Durret, F.; Li, T. S.; Lopes, P. A. A.; Lourenço, A. C. C.; Marshall, J. L.; Medina, G. E.; Muir, J.; Muñoz, R. R.; Sauseda, M.; Schlegel, D. J.; Secco, L. F.; Vivas, A. K.; Wester, W.; Zenteno, A.; Zhang, Y.; Abbott, T. M. C.; Banerji, M.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Castander, F. J.; Crocce, M.; Cunha, C. E.; D'Andrea, C. B.; da Costa, L. N.; Davis, C.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Eifler, T. F.; Evrard, A. E.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gaztanaga, E.; Gerdes, D. W.; Giannantonio, T.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Kent, S.; Krause, E.; Kron, R.; Kuehn, K.; Nuropatkin, N.; Lahav, O.; Lima, M.; Lin, H.; Maia, M. A. G.; March, M.; Martini, P.; McMahon, R. G.; Menanteau, F.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nichol, R. C.; Ogando, R. L. C.; Plazas, A. A.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Thomas, R. C.; Troxel, M. A.; Vikram, V.; Walker, A. R.; Wechsler, R. H.; Weller, J.; Yanny, B.; Zuntz, J.

    2017-10-01

    We present UV, optical, and near-infrared (NIR) photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at 0.47-18.5 days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), and the Hubble Space Telescope (HST). The spectral energy distribution (SED) inferred from this photometry at 0.6 days is well described by a blackbody model with T≈ 8300 K, a radius of R≈ 4.5× {10}14 cm (corresponding to an expansion velocity of v≈ 0.3c), and a bolometric luminosity of {L}{bol}≈ 5× {10}41 erg s-1. At 1.5 days we find a multi-component SED across the optical and NIR, and subsequently we observe rapid fading in the UV and blue optical bands and significant reddening of the optical/NIR colors. Modeling the entire data set, we find that models with heating from radioactive decay of 56Ni, or those with only a single component of opacity from r-process elements, fail to capture the rapid optical decline and red optical/NIR colors. Instead, models with two components consistent with lanthanide-poor and lanthanide-rich ejecta provide a good fit to the data; the resulting “blue” component has {M}{ej}{blue}≈ 0.01 {M}⊙ and {v}{ej}{blue}≈ 0.3 {{c}}, and the “red” component has {M}{ej}{red}≈ 0.04 {M}⊙ and {v}{ej}{red}≈ 0.1 {{c}}. These ejecta masses are broadly consistent with the estimated r-process production rate required to explain the Milky Way r-process abundances, providing the first evidence that binary neutron star (BNS) mergers can be a dominant site of r-process enrichment.

  16. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. II. UV, Optical, and Near-infrared Light Curves and Comparison to Kilonova Models

    Energy Technology Data Exchange (ETDEWEB)

    Cowperthwaite, P. S.; Berger, E.; Villar, V. A.; Metzger, B. D.; Nicholl, M.; Chornock, R.; Blanchard, P. K.; Fong, W.; Margutti, R.; Soares-Santos, M.; Alexander, K. D.; Allam, S.; Annis, J.; Brout, D.; Brown, D. A.; Butler, R. E.; Chen, H. -Y.; Diehl, H. T.; Doctor, Z.; Drout, M. R.; Eftekhari, T.; Farr, B.; Finley, D. A.; Foley, R. J.; Frieman, J. A.; Fryer, C. L.; García-Bellido, J.; Gill, M. S. S.; Guillochon, J.; Herner, K.; Holz, D. E.; Kasen, D.; Kessler, R.; Marriner, J.; Matheson, T.; Neilsen, E. H.; Quataert, E.; Palmese, A.; Rest, A.; Sako, M.; Scolnic, D. M.; Smith, N.; Tucker, D. L.; Williams, P. K. G.; Balbinot, E.; Carlin, J. L.; Cook, E. R.; Durret, F.; Li, T. S.; Lopes, P. A. A.; Lourenço, A. C. C.; Marshall, J. L.; Medina, G. E.; Muir, J.; Muñoz, R. R.; Sauseda, M.; Schlegel, D. J.; Secco, L. F.; Vivas, A. K.; Wester, W.; Zenteno, A.; Zhang, Y.; Abbott, T. M. C.; Banerji, M.; Bechtol, K.; Benoit-Lévy, A.; Bertin, E.; Buckley-Geer, E.; Burke, D. L.; Capozzi, D.; Carnero Rosell, A.; Carrasco Kind, M.; Castander, F. J.; Crocce, M.; Cunha, C. E.; D’Andrea, C. B.; Costa, L. N. da; Davis, C.; DePoy, D. L.; Desai, S.; Dietrich, J. P.; Drlica-Wagner, A.; Eifler, T. F.; Evrard, A. E.; Fernandez, E.; Flaugher, B.; Fosalba, P.; Gaztanaga, E.; Gerdes, D. W.; Giannantonio, T.; Goldstein, D. A.; Gruen, D.; Gruendl, R. A.; Gutierrez, G.; Honscheid, K.; Jain, B.; James, D. J.; Jeltema, T.; Johnson, M. W. G.; Johnson, M. D.; Kent, S.; Krause, E.; Kron, R.; Kuehn, K.; Nuropatkin, N.; Lahav, O.; Lima, M.; Lin, H.; Maia, M. A. G.; March, M.; Martini, P.; McMahon, R. G.; Menanteau, F.; Miller, C. J.; Miquel, R.; Mohr, J. J.; Neilsen, E.; Nichol, R. C.; Ogando, R. L. C.; Plazas, A. A.; Roe, N.; Romer, A. K.; Roodman, A.; Rykoff, E. S.; Sanchez, E.; Scarpine, V.; Schindler, R.; Schubnell, M.; Sevilla-Noarbe, I.; Smith, M.; Smith, R. C.; Sobreira, F.; Suchyta, E.; Swanson, M. E. C.; Tarle, G.; Thomas, D.; Thomas, R. C.; Troxel, M. A.; Vikram, V.; Walker, A. R.; Wechsler, R. H.; Weller, J.; Yanny, B.; Zuntz, J.

    2017-10-16

    We present UV, optical, and NIR photometry of the first electromagnetic counterpart to a gravitational wave source from Advanced LIGO/Virgo, the binary neutron star merger GW170817. Our data set extends from the discovery of the optical counterpart at $0.47$ days to $18.5$ days post-merger, and includes observations with the Dark Energy Camera (DECam), Gemini-South/FLAMINGOS-2 (GS/F2), and the {\\it Hubble Space Telescope} ({\\it HST}). The spectral energy distribution (SED) inferred from this photometry at $0.6$ days is well described by a blackbody model with $T\\approx 8300$ K, a radius of $R\\approx 4.5\\times 10^{14}$ cm (corresponding to an expansion velocity of $v\\approx 0.3c$), and a bolometric luminosity of $L_{\\rm bol}\\approx 5\\times10^{41}$ erg s$^{-1}$. At $1.5$ days we find a multi-component SED across the optical and NIR, and subsequently we observe rapid fading in the UV and blue optical bands and significant reddening of the optical/NIR colors. Modeling the entire data set we find that models with heating from radioactive decay of $^{56}$Ni, or those with only a single component of opacity from $r$-process elements, fail to capture the rapid optical decline and red optical/NIR colors. Instead, models with two components consistent with lanthanide-poor and lanthanide-rich ejecta provide a good fit to the data, the resulting "blue" component has $M_\\mathrm{ej}^\\mathrm{blue}\\approx 0.01$ M$_\\odot$ and $v_\\mathrm{ej}^\\mathrm{blue}\\approx 0.3$c, and the "red" component has $M_\\mathrm{ej}^\\mathrm{red}\\approx 0.04$ M$_\\odot$ and $v_\\mathrm{ej}^\\mathrm{red}\\approx 0.1$c. These ejecta masses are broadly consistent with the estimated $r$-process production rate required to explain the Milky Way $r$-process abundances, providing the first evidence that BNS mergers can be a dominant site of $r$-process enrichment.

  17. Spectral Unmixing With Multiple Dictionaries

    Science.gov (United States)

    Cohen, Jeremy E.; Gillis, Nicolas

    2018-02-01

    Spectral unmixing aims at recovering the spectral signatures of materials, called endmembers, mixed in a hyperspectral or multispectral image, along with their abundances. A typical assumption is that the image contains one pure pixel per endmember, in which case spectral unmixing reduces to identifying these pixels. Many fully automated methods have been proposed in recent years, but little work has been done to allow users to select areas where pure pixels are present manually or using a segmentation algorithm. Additionally, in a non-blind approach, several spectral libraries may be available rather than a single one, with a fixed number (or an upper or lower bound) of endmembers to chose from each. In this paper, we propose a multiple-dictionary constrained low-rank matrix approximation model that address these two problems. We propose an algorithm to compute this model, dubbed M2PALS, and its performance is discussed on both synthetic and real hyperspectral images.

  18. Special topics in spectral distributions

    International Nuclear Information System (INIS)

    French, J.B.

    1980-01-01

    We discuss two problems which relate to the foundations of the subject, and a third about asymptotic properties of spectral distributions. We give also a brief list of topics which should be further explored

  19. Substitution dynamical systems spectral analysis

    CERN Document Server

    Queffélec, Martine

    2010-01-01

    This volume mainly deals with the dynamics of finitely valued sequences, and more specifically, of sequences generated by substitutions and automata. Those sequences demonstrate fairly simple combinatorical and arithmetical properties and naturally appear in various domains. As the title suggests, the aim of the initial version of this book was the spectral study of the associated dynamical systems: the first chapters consisted in a detailed introduction to the mathematical notions involved, and the description of the spectral invariants followed in the closing chapters. This approach, combined with new material added to the new edition, results in a nearly self-contained book on the subject. New tools - which have also proven helpful in other contexts - had to be developed for this study. Moreover, its findings can be concretely applied, the method providing an algorithm to exhibit the spectral measures and the spectral multiplicity, as is demonstrated in several examples. Beyond this advanced analysis, many...

  20. Spectral dimensionality reduction for HMMs

    OpenAIRE

    Foster, Dean P.; Rodu, Jordan; Ungar, Lyle H.

    2012-01-01

    Hidden Markov Models (HMMs) can be accurately approximated using co-occurrence frequencies of pairs and triples of observations by using a fast spectral method in contrast to the usual slow methods like EM or Gibbs sampling. We provide a new spectral method which significantly reduces the number of model parameters that need to be estimated, and generates a sample complexity that does not depend on the size of the observation vocabulary. We present an elementary proof giving bounds on the rel...

  1. Compressive spectroscopy by spectral modulation

    Science.gov (United States)

    Oiknine, Yaniv; August, Isaac; Stern, Adrian

    2017-05-01

    We review two compressive spectroscopy techniques based on modulation in the spectral domain that we have recently proposed. Both techniques achieve a compression ratio of approximately 10:1, however each with a different sensing mechanism. The first technique uses a liquid crystal cell as a tunable filter to modulate the spectral signal, and the second technique uses a Fabry-Perot etalon as a resonator. We overview the specific properties of each of the techniques.

  2. Spectral unmixing: estimating partial abundances

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-01-01

    Full Text Available the ingredients for this chocolate cake? Debba (CSIR) Spectral Unmixing LQM 2009 3 / 22 Background and Research Question Ingredients Quantity unsweetened chocolate unsweetened cocoa powder boiling water flour baking powder baking soda salt unsalted... butter white sugar eggs pure vanilla extract milk Table: Chocolate cake ingredients Debba (CSIR) Spectral Unmixing LQM 2009 4 / 22 Background and Research Question Ingredients Quantity unsweetened chocolate 120 grams unsweetened cocoa powder 28...

  3. Change Detection Analysis With Spectral Thermal Imagery

    National Research Council Canada - National Science Library

    Behrens, Richard

    1998-01-01

    ... (LWIR) region. This study used analysis techniques of differencing, histograms, and principal components analysis to detect spectral changes and investigate the utility of spectral change detection...

  4. DA 495: An Aging Pulsar Wind Nebula with Possible TeV Gamma-Ray Counterpart

    Science.gov (United States)

    Coerver, Anna; Mori, Kaya; Hailey, Charles; Gotthelf, Eric; Mukherjee, Reshmi; Hui, Michelle; Dingus, Brenda; Goodman, Jordan; NuSTAR, HAWC, VERITAS

    2018-01-01

    A pulsar wind nebula is created when a high-mass star collapses and forms an isolated neutron star surrounded by a relativistic particle wind. DA 495 is thought to be such an object, although no pulsations have been detected. DA 495 was first detected in the radio band and is characterized by an annular radio morphology with a radio emission dip in the center. It has been theorized that the wind nebula has an unusually high magnetization of 1.3 mG, and the age of the PWN has been estimated from the 1.3 GHz energy break to be approximately 20 kyr. With such a high wind magnetization, one would expect synchrotron radiation to fall off fairly quickly, yet NuSTAR (the Nuclear Spectroscopic Telescope Array) detected hard X-rays at energies greater than 10 keV, and a study of the Galactic Plane by the HAWC very-high-energy (VHE) gamma-ray telescope revealed a source coincident with DA 495 at energies greater than 10 TeV. This source was also detected at TeV energies by the VERITAS gamma-ray telescope. DA 495 was detected in the X-ray up to 10 keV by both Chandra and XMM-Newton X-ray telescopes before NuSTAR performed follow-up observations of the region in June 2017. DA 495 is one of the first TeV sources observed by the NuSTAR-HAWC-VERITAS Galactic Legacy collaboration. We carried out spectral and imaging analysis of both NuSTAR and Chandra data on DA 495 and will present results of our study of DA 495.

  5. Gamma-ray Burst and Gravitational Wave Counterpart Prospects in the MeV Band with AMEGO

    Science.gov (United States)

    Racusin, Judith; AMEGO Team

    2018-01-01

    The All-sky Medium Energy Gamma-ray Observatory (AMEGO) Probe mission concept is uniquely suited to address open questions in Gamma-ray Burst (GRB) science including the search for counterparts to gravitational-wave events. AMEGO is a wide field of view instrument (~60 deg radius) with a broad energy range (~200 keV to >10 GeV) and excellent continuum sensitivity. The sensitivity improvement will allow for probes of GRB emission mechanisms and jet composition in ways that have not been accessible with previous instruments. Potential for polarization measurement may also have profound impacts on the understanding of GRB mechanisms. AMEGO will also be an excellent facility for the search for gravitational wave counterparts to binary mergers including at least one neutron star, which are thought to produce short duration GRBs. This poster will describe how the AMEGO will advance these fields.

  6. Comparison of Physical Fitness Parameters with EUROFIT Test Battery of Male Adolescent Soccer Players and Sedentary Counterparts

    Directory of Open Access Journals (Sweden)

    Özgür ERİKOĞLU

    2015-09-01

    Full Text Available The aim of this study was to compare physical fitness parameters of male adolescent soccer players and sedentary counterparts. A total of 26 male adolescents participated in this study voluntarily: Active soccer players (n: 3, age x : 13,00 ± 0,00 and sedentary counterparts (n: 13, age x :12,92 ± 0,75. The EUROFIT test battery was used to determine physical fitness. The test battery includes body height and weight measurements, touching the discs, flamingo balan ce, throwing health ball, vertical jumping, sit and reach, sit - up for 30 s, 20 meter sprint run, and 20 meter shuttle run tests. Data were analyzed by Mann Whitney U test. Significance was defined as p.05. In conclusion, children who do sports are more successful on most of the fitness parameters than sedentary children.

  7. Search of MeV-GeV counterparts of TeV sources with AGILE in pointing mode

    Science.gov (United States)

    Rappoldi, A.; Lucarelli, F.; Pittori, C.; Longo, F.; Cattaneo, P. W.; Verrecchia, F.; Tavani, M.; Bulgarelli, A.; Chen, A. W.; Colafrancesco, S.; Donnarumma, I.; Giuliani, A.; Morselli, A.; Sabatini, S.; Vercellone, S.

    2016-03-01

    Context. Known TeV sources detected by major Čerenkov telescopes are investigated to identify possible MeV-GeV γ-ray counterparts. Aims: A systematic study of the known sources in the web-based TeVCat catalog has been performed to search for possible γ-ray counterparts on the AGILE data collected during the first period of operations in observing pointing mode. Methods: For each TeV source, a search for a possible γ-ray counterpart that is based on a multi-source maximum likelihood algorithm is performed on the AGILE data taken with the GRID instrument from July 2007 to October 2009. Results: In the case of high-significance detection, the average γ-ray flux is estimated. For cases of low-significance detection the 95% confidence level (CL) flux upper limit is given. 52 TeV sources out of 152 (corresponding to ~34% of the analysed sample) show a significant excess in the AGILE data covering the pointing observation period. Conclusions: This analysis found 26 new AGILE sources with respect to the AGILE reference catalogs, 15 of which are galactic, 7 are extragalactic and 4 are unidentified. Detailed tables with all available information on the analysed sources are presented. An interactive online version of the considered source list including all the analysis results is also available at the website http://www.asdc.asi.it/agiletevcat/

  8. VLT observations of the magnetar CXO J164710.2-455216 and the detection of a candidate infrared counterpart

    Science.gov (United States)

    Testa, V.; Mignani, R. P.; Hummel, W.; Rea, N.; Israel, G. L.

    2018-01-01

    We present deep observations of the field of the magnetar CXO J164710.2-455216 in the star cluster Westerlund 1, obtained in the near-infrared with the adaptive optics camera NACO@VLT. We detected a possible candidate counterpart at the Chandra position of the magnetar, of magnitudes J = 23.5 ± 0.2, H = 21.0 ± 0.1 and KS = 20.4 ± 0.1. The KS-band measurements available for two epochs (2006 and 2013) do not show significant signs of variability but only a marginal indication that the flux varied (at the 2σ level), consistent with the fact that the observations were taken when CXO J164710.2-455216 was in quiescence. At the same time, we also present colour-magnitude and colour-colour diagrams in the J, H and KS bands from the 2006 epoch only, the only one with observations in all three bands, showing that the candidate counterpart lies in the main bulk of objects describing a relatively well-defined sequence. Therefore, based on its colours and lack of variability, we cannot yet associate the candidate counterpart to CXO J164710.2-455216. Future near-infrared observations of the field, following up a source outburst, would be crucial to confirm the association with the detection of near-infrared variability and colour evolution.

  9. Health and functional status and utilization of health care services among holocaust survivors and their counterparts in Israel.

    Science.gov (United States)

    Iecovich, Esther; Carmel, Sara

    2010-01-01

    To examine differences in health and functional status and in utilization of health services between holocaust survivors and their counterparts; and (b) to investigate if holocaust survivor status is a significant predictor of health status, functional status, and utilization of health services. The study included 1255 respondents of whom 272 were holocaust survivors. Interviews were conducted face-to-face at the respondents' homes. Participants were asked about their health (self-rated health and comorbidity) and functional (ADL and IADL) status, utilization of inpatient and outpatient health care services, age, gender, education, marital status, length of residence in Israel, and if they were holocaust survivors. Holocaust survivors, who were frailer and more chronically ill compared to their counterparts, visited their family physician and the nurse at the health care clinic more often than their counterparts did, and received more homecare services. Yet, there were no differences between them in the utilization of other health care services such as visits to specialists, emergency department, and hospitalizations. Holocaust survivors are more homebound due to more morbidity and functional limitations and therefore receive more health home care services that offset the utilization of other health services. Copyright © 2010 Elsevier Ireland Ltd. All rights reserved.

  10. Spectral filtering for plant production

    Energy Technology Data Exchange (ETDEWEB)

    Young, R.E.; McMahon, M.J.; Rajapakse, N.C.; Becoteau, D.R.

    1994-12-31

    Research to date suggests that spectral filtering can be an effective alternative to chemical growth regulators for altering plant development. If properly implemented, it can be nonchemical and environmentally friendly. The aqueous CuSO{sub 4}, and CuCl{sub 2} solutions in channelled plastic panels have been shown to be effective filters, but they can be highly toxic if the solutions contact plants. Some studies suggest that spectral filtration limited to short EOD intervals can also alter plant development. Future research should be directed toward confirmation of the influence of spectral filters and exposure times on a broader range of plant species and cultivars. Efforts should also be made to identify non-noxious alternatives to aqueous copper solutions and/or to incorporate these chemicals permanently into plastic films and panels that can be used in greenhouse construction. It would also be informative to study the impacts of spectral filters on insect and microbal populations in plant growth facilities. The economic impacts of spectral filtering techniques should be assessed for each delivery methodology.

  11. Solar Spectral Irradiance and Climate

    Science.gov (United States)

    Pilewskie, P.; Woods, T.; Cahalan, R.

    2012-01-01

    Spectrally resolved solar irradiance is recognized as being increasingly important to improving our understanding of the manner in which the Sun influences climate. There is strong empirical evidence linking total solar irradiance to surface temperature trends - even though the Sun has likely made only a small contribution to the last half-century's global temperature anomaly - but the amplitudes cannot be explained by direct solar heating alone. The wavelength and height dependence of solar radiation deposition, for example, ozone absorption in the stratosphere, absorption in the ocean mixed layer, and water vapor absorption in the lower troposphere, contribute to the "top-down" and "bottom-up" mechanisms that have been proposed as possible amplifiers of the solar signal. New observations and models of solar spectral irradiance are needed to study these processes and to quantify their impacts on climate. Some of the most recent observations of solar spectral variability from the mid-ultraviolet to the near-infrared have revealed some unexpected behavior that was not anticipated prior to their measurement, based on an understanding from model reconstructions. The atmospheric response to the observed spectral variability, as quantified in climate model simulations, have revealed similarly surprising and in some cases, conflicting results. This talk will provide an overview on the state of our understanding of the spectrally resolved solar irradiance, its variability over many time scales, potential climate impacts, and finally, a discussion on what is required for improving our understanding of Sun-climate connections, including a look forward to future observations.

  12. Spectral element simulation of ultrafiltration

    DEFF Research Database (Denmark)

    Hansen, M.; Barker, Vincent A.; Hassager, Ole

    1998-01-01

    A spectral element method for simulating stationary 2-D ultrafiltration is presented. The mathematical model is comprised of the Navier-Stokes equations for the velocity field of the fluid and a transport equation for the concentration of the solute. In addition to the presence of the velocity...... vector in the transport equation, the system is coupled by the dependency of the fluid viscosity on the solute concentration and by a concentration-dependent boundary condition for the Navier-Stokes equations at the membrane surface. The spectral element discretization yields a nonlinear algebraic system....... The performance of the spectral element code when applied to several ultrafiltration problems is reported. (C) 1998 Elsevier Science Ltd. All rights reserved....

  13. Spectrally Compatible Iterative Water Filling

    Science.gov (United States)

    Verlinden, Jan; Bogaert, Etienne Vanden; Bostoen, Tom; Zanier, Francesca; Luise, Marco; Cendrillon, Raphael; Moonen, Marc

    2006-12-01

    Until now static spectrum management has ensured that DSL lines in the same cable are spectrally compatible under worst-case crosstalk conditions. Recently dynamic spectrum management (DSM) has been proposed aiming at an increased capacity utilization by adaptation of the transmit spectra of DSL lines to the actual crosstalk interference. In this paper, a new DSM method for downstream ADSL is derived from the well-known iterative water-filling (IWF) algorithm. The amount of boosting of this new DSM method is limited, such that it is spectrally compatible with ADSL. Hence it is referred to as spectrally compatible iterative water filling (SC-IWF). This paper focuses on the performance gains of SC-IWF. This method is an autonomous DSM method (DSM level 1) and it will be investigated together with two other DSM level-1 algorithms, under various noise conditions, namely, iterative water-filling algorithm, and flat power back-off (flat PBO).

  14. Spectrally Compatible Iterative Water Filling

    Directory of Open Access Journals (Sweden)

    Cendrillon Raphael

    2006-01-01

    Full Text Available Until now static spectrum management has ensured that DSL lines in the same cable are spectrally compatible under worst-case crosstalk conditions. Recently dynamic spectrum management (DSM has been proposed aiming at an increased capacity utilization by adaptation of the transmit spectra of DSL lines to the actual crosstalk interference. In this paper, a new DSM method for downstream ADSL is derived from the well-known iterative water-filling (IWF algorithm. The amount of boosting of this new DSM method is limited, such that it is spectrally compatible with ADSL. Hence it is referred to as spectrally compatible iterative water filling (SC-IWF. This paper focuses on the performance gains of SC-IWF. This method is an autonomous DSM method (DSM level 1 and it will be investigated together with two other DSM level-1 algorithms, under various noise conditions, namely, iterative water-filling algorithm, and flat power back-off (flat PBO.

  15. Spectral scheme for spacetime physics

    International Nuclear Information System (INIS)

    Seriu, Masafumi

    2002-01-01

    Based on the spectral representation of spatial geometry, we construct an analysis scheme for spacetime physics and cosmology, which enables us to compare two or more universes with each other. In this scheme the spectral distance plays a central role, which is the measure of closeness between two geometries defined in terms of the spectra. We apply this scheme for analyzing the averaging problem in cosmology; we explicitly investigate the time evolution of the spectra, distance between two nearby spatial geometries, simulating the relation between the real Universe and its model. We then formulate the criteria for a model to be a suitable one

  16. Spectral ellipsometry of nanodiamond composite

    International Nuclear Information System (INIS)

    Yastrebov, S.G.; Ivanov-Omskij, V.I.; Gordeev, S.K.; Garriga, M.; Alonso, I.A.

    2006-01-01

    Methods of spectral ellipsometry were applied for analysis of optical properties of nanodiamond based composite in spectral region 1.4-5 eV. The nanocomposite was synthesized by molding of ultradispersed nanodiamond powder in the course of heterogeneous chemical reaction of decomposition of methane, forming pyrocarbon interconnecting nanodiamond grains. The energy of σ + π plasmon of pyrocarbon component of nanodiamond composite was restored which proves to be ∼ 24 eV; using this value, an estimation was done of pyrocarbon matrix density, which occurs to be 2 g/cm 3 [ru

  17. SPECTRAL DEPENDENT ELECTRICAL CHARACTERISTICS OF ...

    African Journals Online (AJOL)

    ABSTRACT: The illuminated current-voltage characteristics of thin film a-Si:H. p-i-n solar cells were measured for the visible and near infrared spectral regions. The fill factor, the conversion efficiency, the open circuit Voltage and the short circuit current were compared to the parameters of crystalline silicon pit-junction.

  18. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Abstract. Information is carried in changes of a signal. The paper starts with revis- iting Dudley's concept of the carrier nature of speech. It points to its close connection to modulation spectra of speech and argues against short-term spectral envelopes as dominant carriers of the linguistic information in speech. The history of ...

  19. Optical Spectral Variability of Blazars

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... It is well established that blazars show flux variations in the complete electromagnetic (EM) spectrum on all possible time scales ranging from a few tens of minutes to several years. Here, we report the review of optical flux and spectral variability properties of different classes of blazars on IDV and STV ...

  20. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Some of the history of gradual infusion of the modulation spectrum concept into Automatic recognition of speech (ASR) comes next, pointing to the relationship of modulation spectrum processing to wellaccepted ASR techniques such as dynamic speech features or RelAtive SpecTrAl (RASTA) filtering. Next ...

  1. Spectral problems for operator matrices

    NARCIS (Netherlands)

    Bátkai, A.; Binding, P.; Dijksma, A.; Hryniv, R.; Langer, H.

    2005-01-01

    We study spectral properties of 2 × 2 block operator matrices whose entries are unbounded operators between Banach spaces and with domains consisting of vectors satisfying certain relations between their components. We investigate closability in the product space, essential spectra and generation of

  2. Spectral Methods for Numerical Relativity

    Directory of Open Access Journals (Sweden)

    Grandclément Philippe

    2009-01-01

    Full Text Available Equations arising in general relativity are usually too complicated to be solved analytically and one must rely on numerical methods to solve sets of coupled partial differential equations. Among the possible choices, this paper focuses on a class called spectral methods in which, typically, the various functions are expanded in sets of orthogonal polynomials or functions. First, a theoretical introduction of spectral expansion is given with a particular emphasis on the fast convergence of the spectral approximation. We then present different approaches to solving partial differential equations, first limiting ourselves to the one-dimensional case, with one or more domains. Generalization to more dimensions is then discussed. In particular, the case of time evolutions is carefully studied and the stability of such evolutions investigated. We then present results obtained by various groups in the field of general relativity by means of spectral methods. Work, which does not involve explicit time-evolutions, is discussed, going from rapidly-rotating strange stars to the computation of black-hole–binary initial data. Finally, the evolution of various systems of astrophysical interest are presented, from supernovae core collapse to black-hole–binary mergers.

  3. Functional Analysis-Spectral Theoryl

    Indian Academy of Sciences (India)

    Home; Journals; Resonance – Journal of Science Education; Volume 6; Issue 4. Functional Analysis - Spectral Theory1. Cherian Varughese. Book Review Volume 6 Issue 4 April 2001 pp 91-92 ... Author Affiliations. Cherian Varughese1. Indian Statistical Institute, 8th Mile, Mysore Road, Bangalore 560 059, India.

  4. Spectral Diagonal Ensemble Kalman Filters

    Czech Academy of Sciences Publication Activity Database

    Kasanický, Ivan; Mandel, Jan; Vejmelka, Martin

    2015-01-01

    Roč. 22, č. 4 (2015), s. 485-497 ISSN 1023-5809 R&D Projects: GA ČR GA13-34856S Grant - others:NSF(US) DMS -1216481 Institutional support: RVO:67985807 Keywords : data assimilation * ensemble Kalman filter * spectral representation Subject RIV: DG - Athmosphere Sciences, Meteorology Impact factor: 1.321, year: 2015

  5. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    Some of the history of gradual infusion of the modulation spectrum concept into Automatic recognition of speech (ASR) comes next, pointing to the relationship of modulation spectrum processing to wellaccepted ASR techniques such as dynamic speech features or RelAtive SpecTrAl (RASTA) filtering. Next, the frequency ...

  6. Speech recognition from spectral dynamics

    Indian Academy of Sciences (India)

    automatic recognition of speech (ASR). Instead, likely for historical reasons, envelopes of power spectrum were adopted as main carrier of linguistic information in ASR. However, the relationships between phonetic values of sounds and their short-term spectral envelopes are not straightforward. Consequently, this asks for ...

  7. Spectral representation of Gaussian semimartingales

    DEFF Research Database (Denmark)

    Basse-O'Connor, Andreas

    2009-01-01

    The aim of the present paper is to characterize the spectral representation of Gaussian semimartingales. That is, we provide necessary and sufficient conditions on the kernel K for X t =∫ K t (s) dN s to be a semimartingale. Here, N denotes an independently scattered Gaussian random measure...

  8. Assessing FRET using Spectral Techniques

    Science.gov (United States)

    Leavesley, Silas J.; Britain, Andrea L.; Cichon, Lauren K.; Nikolaev, Viacheslav O.; Rich, Thomas C.

    2015-01-01

    Förster resonance energy transfer (FRET) techniques have proven invaluable for probing the complex nature of protein–protein interactions, protein folding, and intracellular signaling events. These techniques have traditionally been implemented with the use of one or more fluorescence band-pass filters, either as fluorescence microscopy filter cubes, or as dichroic mirrors and band-pass filters in flow cytometry. In addition, new approaches for measuring FRET, such as fluorescence lifetime and acceptor photobleaching, have been developed. Hyperspectral techniques for imaging and flow cytometry have also shown to be promising for performing FRET measurements. In this study, we have compared traditional (filter-based) FRET approaches to three spectral-based approaches: the ratio of acceptor-to-donor peak emission, linear spectral unmixing, and linear spectral unmixing with a correction for direct acceptor excitation. All methods are estimates of FRET efficiency, except for one-filter set and three-filter set FRET indices, which are included for consistency with prior literature. In the first part of this study, spectrofluorimetric data were collected from a CFP–Epac–YFP FRET probe that has been used for intracellular cAMP measurements. All comparisons were performed using the same spectrofluorimetric datasets as input data, to provide a relevant comparison. Linear spectral unmixing resulted in measurements with the lowest coefficient of variation (0.10) as well as accurate fits using the Hill equation. FRET efficiency methods produced coefficients of variation of less than 0.20, while FRET indices produced coefficients of variation greater than 8.00. These results demonstrate that spectral FRET measurements provide improved response over standard, filter-based measurements. Using spectral approaches, single-cell measurements were conducted through hyperspectral confocal microscopy, linear unmixing, and cell segmentation with quantitative image analysis

  9. A challenge to identify an optical counterpart of the gravitational wave event GW151226 with Hyper Suprime-Cam†

    Science.gov (United States)

    Utsumi, Yousuke; Tominaga, Nozomu; Tanaka, Masaomi; Morokuma, Tomoki; Yoshida, Michitoshi; Asakura, Yuichiro; Finet, François; Furusawa, Hisanori; Kawabata, Koji S.; Liu, Wei; Matsubayashi, Kazuya; Moritani, Yuki; Motohara, Kentaro; Nakata, Fumiaki; Ohta, Kouji; Terai, Tsuyoshi; Uemura, Makoto; Yasuda, Naoki

    2018-01-01

    We present the results of detailed analysis of an optical imaging survey conducted using the Subaru/Hyper Suprime-Cam (HSC) that aimed to identify an optical counterpart to the gravitational wave event GW151226. In half a night, the i- and z-band imaging survey by HSC covered 63.5 deg2 of the error region, which contains about 7% of the LIGO localization probability, and the same field was observed in three different epochs. The detectable magnitude of the candidates in a differenced image is evaluated as i ˜ 23.2 mag for the requirement of at least two 5 σ detections, and 1744 candidates are discovered. Assuming a kilonova as an optical counterpart, we compare the optical properties of the candidates with model predictions. A red and rapidly declining light curve condition enables the discrimination of a kilonova from other transients, and a small number of candidates satisfy this condition. The presence of stellar-like counterparts in the reference frame suggests that the surviving candidates are likely to be flare stars. The fact that most of those candidates are in the galactic plane, |b| < 5°, supports this interpretation. We also check whether the candidates are associated with the nearby GLADE galaxies, which reduces the number of contaminants even with a looser color cut. When a better probability map (with localization accuracy of ˜50 deg2) is available, kilonova searches of up to approximately 200 Mpc will become feasible by conducting immediate follow-up observations with an interval of 3-6 d.

  10. DISCOVERY OF THE OPTICAL/ULTRAVIOLET/GAMMA-RAY COUNTERPART TO THE ECLIPSING MILLISECOND PULSAR J1816+4510

    Energy Technology Data Exchange (ETDEWEB)

    Kaplan, D. L.; Kotulla, R.; Biwer, C. M.; Day, D. F. [Physics Department, University of Wisconsin-Milwaukee, Milwaukee WI 53211 (United States); Stovall, K.; Dartez, L.; Ford, A. J.; Garcia, A.; Jenet, F. A. [Center for Advanced Radio Astronomy and Department of Physics and Astronomy, University of Texas at Brownsville, Brownsville, TX 78520 (United States); Ransom, S. M. [National Radio Astronomy Observatory, 520 Edgemont Road, Charlottesville, VA 22901 (United States); Roberts, M. S. E. [Eureka Scientific, Inc., 2452 Delmer Street, Suite 100, Oakland, CA 94602-3017 (United States); Archibald, A. M.; Karako, C.; Kaspi, V. M.; Lynch, R. S. [Department of Physics, McGill University, 3600 University Street, Montreal, QC H3A 2T8 (Canada); Boyles, J.; Lorimer, D. R.; McLaughlin, M. A. [Department of Physics, West Virginia University, White Hall, 115 Willey Street, Morgantown, WV 26506 (United States); Hessels, J. W. T.; Kondratiev, V. I., E-mail: kaplan@uwm.edu [ASTRON, the Netherlands Institute for Radio Astronomy, Postbus 2, 7990 AA, Dwingeloo (Netherlands); and others

    2012-07-10

    The energetic, eclipsing millisecond pulsar J1816+4510 was recently discovered in a low-frequency radio survey with the Green Bank Telescope. With an orbital period of 8.7 hr and a minimum companion mass of 0.16 M{sub Sun }, it appears to belong to an increasingly important class of pulsars that are ablating their low-mass companions. We report the discovery of the {gamma}-ray counterpart to this pulsar and present a likely optical/ultraviolet counterpart as well. Using the radio ephemeris, we detect pulsations in the unclassified {gamma}-ray source 2FGL J1816.5+4511, implying an efficiency of {approx}25% in converting the pulsar's spin-down luminosity into {gamma}-rays and adding PSR J1816+4510 to the large number of millisecond pulsars detected by Fermi. The likely optical/UV counterpart was identified through position coincidence (<0.''1) and unusual colors. Assuming that it is the companion, with R = 18.27 {+-} 0.03 mag and effective temperature {approx}> 15,000 K, it would be among the brightest and hottest of low-mass pulsar companions and appears qualitatively different from other eclipsing pulsar systems. In particular, current data suggest that it is a factor of two larger than most white dwarfs of its mass but a factor of four smaller than its Roche lobe. We discuss possible reasons for its high temperature and odd size, and suggest that it recently underwent a violent episode of mass loss. Regardless of origin, its brightness and the relative unimportance of irradiation make it an ideal target for a mass, and hence a neutron star mass, determination.

  11. QUEST FOR COSMOS SUBMILLIMETER GALAXY COUNTERPARTS USING CARMA AND VLA: IDENTIFYING THREE HIGH-REDSHIFT STARBURST GALAXIES

    International Nuclear Information System (INIS)

    Smolčić, V.; Navarrete, F.; Bertoldi, F.; Aravena, M.; Sheth, K.; Ilbert, O.; Yun, M. S.; Salvato, M.; Finoguenov, A.; McCracken, H. J.; Diener, C.; Aretxaga, I.; Hughes, D.; Wilson, G.; Riechers, D. A.; Capak, P.; Scoville, N. Z.; Karim, A.; Schinnerer, E.

    2012-01-01

    We report on interferometric observations at 1.3 mm at 2''-3'' resolution using the Combined Array for Research in Millimeter-wave Astronomy. We identify multi-wavelength counterparts of three submillimeter galaxies (SMGs; F 1m > 5.5 mJy) in the COSMOS field, initially detected with MAMBO and AzTEC bolometers at low, ∼10''-30'', resolution. All three sources—AzTEC/C1, Cosbo-3, and Cosbo-8—are identified to coincide with positions of 20 cm radio sources. Cosbo-3, however, is not associated with the most likely radio counterpart, closest to the MAMBO source position, but with that farther away from it. This illustrates the need for intermediate-resolution (∼2'') mm-observations to identify the correct counterparts of single-dish-detected SMGs. All of our three sources become prominent only at NIR wavelengths, and their mm-to-radio flux based redshifts suggest that they lie at redshifts z ∼> 2. As a proof of concept, we show that photometric redshifts can be well determined for SMGs, and we find photometric redshifts of 5.6 ± 1.2, 1.9 +0.9 –0.5 , and ∼4 for AzTEC/C1, Cosbo-3, and Cosbo-8, respectively. Using these we infer that these galaxies have radio-based star formation rates of ∼> 1000 M ☉ yr –1 and IR luminosities of ∼10 13 L ☉ consistent with properties of high-redshift SMGs. In summary, our sources reflect a variety of SMG properties in terms of redshift and clustering, consistent with the framework that SMGs are progenitors of z ∼ 2 and today's passive galaxies.

  12. Comparison of nutritional value of transgenic peanut expressing bar and rcg3 genes with non-transgenic counterparts

    International Nuclear Information System (INIS)

    Robab, U.E.; )

    2014-01-01

    The transgenic peanut plants expressing bar and rcg3 genes were subjected to assessment of any change in nutritional value of the crop at various locations. The protein and fat contents of transgenic lines were compared with the non-transgenic parent varieties. Protein content in the transgenic lines was higher as compared to that in non-transgenic counterparts and differences among locations for fat and protein content were significant. No differences among fatty acids were recorded for genes, events and locations. Irrespective of small differences, all the values were in range described for this crop and transgenic lines appeared to be substantially equivalent to non-transgenic parent varieties. (author)

  13. Interstimulus interval dependence of the auditory vertex response and its magnetic counterpart: implications for their neural generation.

    Science.gov (United States)

    Hari, R; Kaila, K; Katila, T; Tuomisto, T; Varpula, T

    1982-11-01

    Auditory vertex responses elicited by short tone bursts were compared with their magnetic counter parts. Special attention was paid to the behaviour of the N100 deflection of the response. Electrical responses were recorded from scalp locations Fp2, Fz, Cz, Pz, C4 and T4 and the magnetic responses half way between P4 and T6, at a point where the response has one of its amplitude extrema. Different ISIs (from 1 to 16 sec) were applied in order to differentiate specific and nonspecific evoked potential components from each other. The main results were as follows: (1) The scalp distsribution of the electical vertex response depends on the ISI used: with frequent stimulation there are no marked differences in the amplitudes of N100 between frontal and central areas but with long ISIs the amplitude maxima move to the vertex. (2) The magnetic responses also show a clear ISI dependence. The magnetic counterpart of N100 saturates at shorter ISIs than N100 recorded from the vertex. Independent of the ISI the magnetic counterpart of P200 is constantly very small. On the basis of the different sensitivities of the EEG and MEG to current sources of different orientations it is concluded that the auditory vertex response contains both modality specific and non-specific components. Experimental conditions, especially the ISI used, determine the relative contributions of these components to the potential recorded on the scalp.

  14. An Enhanced Method for Scheduling Observations of Large Sky Error Regions for Finding Optical Counterparts to Transients

    Energy Technology Data Exchange (ETDEWEB)

    Rana, Javed; Singhal, Akshat; Gadre, Bhooshan; Bhalerao, Varun; Bose, Sukanta, E-mail: javed@iucaa.in [Inter-University Centre for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411 007 (India)

    2017-04-01

    The discovery and subsequent study of optical counterparts to transient sources is crucial for their complete astrophysical understanding. Various gamma-ray burst (GRB) detectors, and more notably the ground-based gravitational wave detectors, typically have large uncertainties in the sky positions of detected sources. Searching these large sky regions spanning hundreds of square degrees is a formidable challenge for most ground-based optical telescopes, which can usually image less than tens of square degrees of the sky in a single night. We present algorithms for better scheduling of such follow-up observations in order to maximize the probability of imaging the optical counterpart, based on the all-sky probability distribution of the source position. We incorporate realistic observing constraints such as the diurnal cycle, telescope pointing limitations, available observing time, and the rising/setting of the target at the observatory’s location. We use simulations to demonstrate that our proposed algorithms outperform the default greedy observing schedule used by many observatories. Our algorithms are applicable for follow-up of other transient sources with large positional uncertainties, such as Fermi -detected GRBs, and can easily be adapted for scheduling radio or space-based X-ray follow-up.

  15. Detection of an Optical Counterpart to the ALFALFA Ultra-compact High-velocity Cloud AGC 249525

    Science.gov (United States)

    Janesh, William; Rhode, Katherine L.; Salzer, John J.; Janowiecki, Steven; Adams, Elizabeth A. K.; Haynes, Martha P.; Giovanelli, Riccardo; Cannon, John M.

    2017-03-01

    We report on the detection at >98% confidence of an optical counterpart to AGC 249525, an ultra-compact high-velocity cloud (UCHVC) discovered by the Arecibo Legacy Fast ALFA survey blind neutral hydrogen survey. UCHVCs are compact, isolated H I clouds with properties consistent with their being nearby low-mass galaxies, but without identified counterparts in extant optical surveys. Analysis of the resolved stellar sources in deep g- and I-band imaging from the WIYN pODI camera reveals a clustering of possible red giant branch stars associated with AGC 249525 at a distance of 1.64 ± 0.45 Mpc. Matching our optical detection with the H I synthesis map of AGC 249525 from Adams et al. shows that the stellar overdensity is exactly coincident with the highest-density H I contour from that study. Combining our optical photometry and the H I properties of this object yields an absolute magnitude of -7.1≤slant {M}V≤slant -4.5, a stellar mass between 2.2+/- 0.6× {10}4 {M}⊙ and 3.6+/- 1.0× {10}5 {M}⊙ , and an H I to stellar mass ratio between 9 and 144. This object has stellar properties within the observed range of gas-poor ultra-faint dwarfs in the Local Group, but is gas-dominated.

  16. Life-cycle fossil energy consumption and greenhouse gas emissions of bioderived chemicals and their conventional counterparts.

    Science.gov (United States)

    Adom, Felix; Dunn, Jennifer B; Han, Jeongwoo; Sather, Norm

    2014-12-16

    Biomass-derived chemical products may offer reduced environmental impacts compared to their fossil-derived counterparts and could improve profit margins at biorefineries when coproduced with higher-volume, lower-profit margin biofuels. It is important to assess on a life-cycle basis the energy and environmental impacts of these bioproducts as compared to conventional, fossil-derived products. We undertook a life-cycle analysis of eight bioproducts produced from either algal-derived glycerol or corn stover-derived sugars. Selected on the basis of technology readiness and market potential, the bioproducts are propylene glycol, 1,3-propanediol, 3-hydroxypropionic acid, acrylic acid, polyethylene, succinic acid, isobutanol, and 1,4-butanediol. We developed process simulations to obtain energy and material flows in the production of each bioproduct and examined sensitivity of these flows to process design assumptions. Conversion process data for fossil-derived products were based on the literature. Conversion process data were combined with upstream parameters in the Greenhouse gases, Regulated Emissions, and Energy use in Transportation (GREET) model to generate life-cycle greenhouse gas (GHG) emissions and fossil energy consumption (FEC) for each bioproduct and its corresponding petroleum-derived product. The bioproducts uniformly offer GHG emissions reductions compared to their fossil counterparts ranging from 39 to 86% on a cradle-to-grave basis. Similarly, FEC was lower for bioproducts than for conventional products.

  17. The Effect of the Negotiator's Social Power as a Function of the Counterpart's Emotional Reactions in a Computer Mediated Negotiation

    Directory of Open Access Journals (Sweden)

    Shlomo Hareli

    2013-11-01

    Full Text Available A negotiator’s own power and their counterpart’s emotional reaction to the negotiation both influence the outcome of negotiations. The present research addressed the question of their relative importance. On one hand, social power should be potent regardless of the other’s emotions. On the other hand, the counterpart’s emotional reactions inform about the ongoing state of the negotiation, and as such are more diagnostic than the more distal power cue. In a simulated computer mediated negotiation, 248 participants assumed the role of a vendor of computerized avionics test equipment and their objective was to negotiate the price, the warranty period, and the number of software updates that the buyer will receive free of charge. Participants negotiated the sale after being primed with either high or low power or not primed at all (control condition. They received information that their counterpart was either happy or angry or emotionally neutral. The findings showed that even though power was an important factor at the start of negotiations, the informative value of emotion information took precedence over time. This implies that emotional information may erase any advantage that counterparts have in a negotiation thanks to their higher social power.

  18. Spectral Tensor-Train Decomposition

    DEFF Research Database (Denmark)

    Bigoni, Daniele; Engsig-Karup, Allan Peter; Marzouk, Youssef M.

    2016-01-01

    discretizations of the target function. We assess the performance of the method on a range of numerical examples: a modified set of Genz functions with dimension up to 100, and functions with mixed Fourier modes or with local features. We observe significant improvements in performance over an anisotropic......The accurate approximation of high-dimensional functions is an essential task in uncertainty quantification and many other fields. We propose a new function approximation scheme based on a spectral extension of the tensor-train (TT) decomposition. We first define a functional version of the TT.......e., the “cores”) comprising the functional TT decomposition. This result motivates an approximation scheme employing polynomial approximations of the cores. For functions with appropriate regularity, the resulting spectral tensor-train decomposition combines the favorable dimension-scaling of the TT...

  19. Spectral computations for bounded operators

    CERN Document Server

    Ahues, Mario; Limaye, Balmohan

    2001-01-01

    Exact eigenvalues, eigenvectors, and principal vectors of operators with infinite dimensional ranges can rarely be found. Therefore, one must approximate such operators by finite rank operators, then solve the original eigenvalue problem approximately. Serving as both an outstanding text for graduate students and as a source of current results for research scientists, Spectral Computations for Bounded Operators addresses the issue of solving eigenvalue problems for operators on infinite dimensional spaces. From a review of classical spectral theory through concrete approximation techniques to finite dimensional situations that can be implemented on a computer, this volume illustrates the marriage of pure and applied mathematics. It contains a variety of recent developments, including a new type of approximation that encompasses a variety of approximation methods but is simple to verify in practice. It also suggests a new stopping criterion for the QR Method and outlines advances in both the iterative refineme...

  20. Biomarkers and Biological Spectral Imaging

    Science.gov (United States)

    2001-01-23

    karyotyping (SKY) in hematological neoplasia [4259-13] B. S. Preiss, R. K. Pedersen, G. B. Kerndrup, Odense Univ. Hospital (Denmark) 60 Structure of...astronomy and airborne monitoring to forensic and biomedical sciences or industrial qualit\\ and process monitoring. There is growing need for a sensitive...SPIE Vol. 4259 55 Spectral Karyotyping (SKY) in Hematologic Neoplasia. Birgitte S. Preiss*a, Rikke K. Pedersena, Gitte B. Kerndrupa aInstitute of

  1. Chebyshev and Fourier spectral methods

    CERN Document Server

    Boyd, John P

    2001-01-01

    Completely revised text focuses on use of spectral methods to solve boundary value, eigenvalue, and time-dependent problems, but also covers Hermite, Laguerre, rational Chebyshev, sinc, and spherical harmonic functions, as well as cardinal functions, linear eigenvalue problems, matrix-solving methods, coordinate transformations, methods for unbounded intervals, spherical and cylindrical geometry, and much more. 7 Appendices. Glossary. Bibliography. Index. Over 160 text figures.

  2. Abundance estimation of spectrally similar minerals

    CSIR Research Space (South Africa)

    Debba, Pravesh

    2009-07-01

    Full Text Available This paper evaluates a spectral unmixing method for estimating the partial abundance of spectrally similar minerals in complex mixtures. The method requires formulation of a linear function of individual spectra of individual minerals. The first...

  3. Relevance of Spectral Cues for Auditory Spatial Processing in the Occipital Cortex of the Blind

    Science.gov (United States)

    Voss, Patrice; Lepore, Franco; Gougoux, Frédéric; Zatorre, Robert J.

    2011-01-01

    We have previously shown that some blind individuals can localize sounds more accurately than their sighted counterparts when one ear is obstructed, and that this ability is strongly associated with occipital cortex activity. Given that spectral cues are important for monaurally localizing sounds when one ear is obstructed, and that blind individuals are more sensitive to small spectral differences, we hypothesized that enhanced use of spectral cues via occipital cortex mechanisms could explain the better performance of blind individuals in monaural localization. Using positron-emission tomography (PET), we scanned blind and sighted persons as they discriminated between sounds originating from a single spatial position, but with different spectral profiles that simulated different spatial positions based on head-related transfer functions. We show here that a sub-group of early blind individuals showing superior monaural sound localization abilities performed significantly better than any other group on this spectral discrimination task. For all groups, performance was best for stimuli simulating peripheral positions, consistent with the notion that spectral cues are more helpful for discriminating peripheral sources. PET results showed that all blind groups showed cerebral blood flow increases in the occipital cortex; but this was also the case in the sighted group. A voxel-wise covariation analysis showed that more occipital recruitment was associated with better performance across all blind subjects but not the sighted. An inter-regional covariation analysis showed that the occipital activity in the blind covaried with that of several frontal and parietal regions known for their role in auditory spatial processing. Overall, these results support the notion that the superior ability of a sub-group of early-blind individuals to localize sounds is mediated by their superior ability to use spectral cues, and that this ability is subserved by cortical processing in

  4. Calibration with near-continuous spectral measurements

    DEFF Research Database (Denmark)

    Nielsen, Henrik Aalborg; Rasmussen, Michael; Madsen, Henrik

    2001-01-01

    In chemometrics traditional calibration in case of spectral measurements express a quantity of interest (e.g. a concentration) as a linear combination of the spectral measurements at a number of wavelengths. Often the spectral measurements are performed at a large number of wavelengths and in thi...... by an example in which the octane number of gasoline is related to near infrared spectral measurements. The performance is found to be much better that for the traditional calibration methods....

  5. USGS Spectral Library Version 7

    Science.gov (United States)

    Kokaly, Raymond F.; Clark, Roger N.; Swayze, Gregg A.; Livo, K. Eric; Hoefen, Todd M.; Pearson, Neil C.; Wise, Richard A.; Benzel, William M.; Lowers, Heather A.; Driscoll, Rhonda L.; Klein, Anna J.

    2017-04-10

    We have assembled a library of spectra measured with laboratory, field, and airborne spectrometers. The instruments used cover wavelengths from the ultraviolet to the far infrared (0.2 to 200 microns [μm]). Laboratory samples of specific minerals, plants, chemical compounds, and manmade materials were measured. In many cases, samples were purified, so that unique spectral features of a material can be related to its chemical structure. These spectro-chemical links are important for interpreting remotely sensed data collected in the field or from an aircraft or spacecraft. This library also contains physically constructed as well as mathematically computed mixtures. Four different spectrometer types were used to measure spectra in the library: (1) Beckman™ 5270 covering the spectral range 0.2 to 3 µm, (2) standard, high resolution (hi-res), and high-resolution Next Generation (hi-resNG) models of Analytical Spectral Devices (ASD) field portable spectrometers covering the range from 0.35 to 2.5 µm, (3) Nicolet™ Fourier Transform Infra-Red (FTIR) interferometer spectrometers covering the range from about 1.12 to 216 µm, and (4) the NASA Airborne Visible/Infra-Red Imaging Spectrometer AVIRIS, covering the range 0.37 to 2.5 µm. Measurements of rocks, soils, and natural mixtures of minerals were made in laboratory and field settings. Spectra of plant components and vegetation plots, comprising many plant types and species with varying backgrounds, are also in this library. Measurements by airborne spectrometers are included for forested vegetation plots, in which the trees are too tall for measurement by a field spectrometer. This report describes the instruments used, the organization of materials into chapters, metadata descriptions of spectra and samples, and possible artifacts in the spectral measurements. To facilitate greater application of the spectra, the library has also been convolved to selected spectrometer and imaging spectrometers sampling and

  6. Calibrating spectral images using penalized likelihood

    NARCIS (Netherlands)

    Heijden, van der G.W.A.M.; Glasbey, C.

    2003-01-01

    A new method is presented for automatic correction of distortions and for spectral calibration (which band corresponds to which wavelength) of spectral images recorded by means of a spectrograph. The method consists of recording a bar-like pattern with an illumination source with spectral bands

  7. Spectral properties of generalized eigenparameter dependent ...

    African Journals Online (AJOL)

    Jost function, spectrum, the spectral singularities, and the properties of the principal vectors corresponding to the spectral singularities of L, if. ∞Σn=1 n(∣1 - an∣ + ∣bnl) < ∞. Mathematics Subject Classication (2010): 34L05, 34L40, 39A70, 47A10, 47A75. Key words: Discrete equations, eigenparameter, spectral analysis, ...

  8. Spectral Lag Evolution among -Ray Burst Pulses

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... We analyse the spectral lag evolution of -ray burst (GRB) pulses with observations by CGRO/BATSE. No universal spectral lag evolution feature and pulse luminosity-lag relation within a GRB is observed.Our results suggest that the spectral lag would be due to radiation physics and dynamics of a given ...

  9. Spectral multitude and spectral dynamics reflect changing conjugation length in single molecules of oligophenylenevinylenes

    KAUST Repository

    Kobayashi, Hiroyuki

    2012-01-01

    Single-molecule study of phenylenevinylene oligomers revealed distinct spectral forms due to different conjugation lengths which are determined by torsional defects. Large spectral jumps between different spectral forms were ascribed to torsional flips of a single phenylene ring. These spectral changes reflect the dynamic nature of electron delocalization in oligophenylenevinylenes and enable estimation of the phenylene torsional barriers. © 2012 The Owner Societies.

  10. [Spectral analysis in nanometer material science].

    Science.gov (United States)

    Chen, Wei; Sun, Shi-gang

    2002-06-01

    Spectral analysis is an important means in studies of nanometer scale systems, and is essential for deep understanding the structure and properties of nanometer materials. This paper reviews the recent progresses made in studies of nanometer materials using spectral analysis methods such as UV-Visible spectroscopy, FTIR spectroscopy, Raman spectroscopy, Mössbauer spectroscopy, positron annihilation and photoacoustic spectroscopy. The principle, characteristics and applications of most frequently employed spectral methods are introduced briefly and illustrated with typical examples. Future perspectives of spectral analysis in nanometer field are discussed. New directions of establishing spectral analysis methods at nanometer scale resolution and developing new spectroscopy technology in nanometer material studies are also emphasized.

  11. Distribution of apparent activation energy counterparts during thermo - And thermo-oxidative degradation of Aronia melanocarpa (black chokeberry).

    Science.gov (United States)

    Janković, Bojan; Marinović-Cincović, Milena; Janković, Marija

    2017-09-01

    Kinetics of degradation for Aronia melanocarpa fresh fruits in argon and air atmospheres were investigated. The investigation was based on probability distributions of apparent activation energy of counterparts (ε a ). Isoconversional analysis results indicated that the degradation process in an inert atmosphere was governed by decomposition reactions of esterified compounds. Also, based on same kinetics approach, it was assumed that in an air atmosphere, the primary compound in degradation pathways could be anthocyanins, which undergo rapid chemical reactions. A new model of reactivity demonstrated that, under inert atmospheres, expectation values for ε a occured at levels of statistical probability. These values corresponded to decomposition processes in which polyphenolic compounds might be involved. ε a values obeyed laws of binomial distribution. It was established that, for thermo-oxidative degradation, Poisson distribution represented a very successful approximation for ε a values where there was additional mechanistic complexity and the binomial distribution was no longer valid. Copyright © 2017 Elsevier Ltd. All rights reserved.

  12. Differential production of proteolytic enzymes by normal human fibroblasts and their counterparts transformed by treatment with 60Co gamma rays

    International Nuclear Information System (INIS)

    Nishitani, Koji; Namba, Masayoshi; Ohkubo, Shigeki; Kimoto, Tetsuo

    1985-01-01

    Production of proteolytic enzymes by human fibroblasts in the process of transformation was investigated. The cells used were normal human fibroblasts (KSM-6) and their in vitro counterparts transformed by treatment with 60 Co gamma rays (KMST-6). Cells seeded by treatment with EDTA were cultured in a serum free medium. Proteolytic enzymes in the culture medium of cells were assayed using a synthetic substrate, N-α-(p-tosyl)-L-arginine ( 3 H) methyl ester hydrochloride. The transformed cells (KMST-6) produced a larger amount of enzymes than normal cells (KMS-6). The enzyme production in both cell lines was high in the exponential growth stage and then decreased as the cells reached confluency. The proteolytic enzymes produced by these cells were trypsin- and thrombin-like enzymes. Cell growth of KMST-6 or KMS-6 was not inhibited by the addition of protease inhibitors to the culture medium. (author)

  13. Using Penelope to assess the correctness of NASA Ada software: A demonstration of formal methods as a counterpart to testing

    Science.gov (United States)

    Eichenlaub, Carl T.; Harper, C. Douglas; Hird, Geoffrey

    1993-01-01

    Life-critical applications warrant a higher level of software reliability than has yet been achieved. Since it is not certain that traditional methods alone can provide the required ultra reliability, new methods should be examined as supplements or replacements. This paper describes a mathematical counterpart to the traditional process of empirical testing. ORA's Penelope verification system is demonstrated as a tool for evaluating the correctness of Ada software. Grady Booch's Ada calendar utility package, obtained through NASA, was specified in the Larch/Ada language. Formal verification in the Penelope environment established that many of the package's subprograms met their specifications. In other subprograms, failed attempts at verification revealed several errors that had escaped detection by testing.

  14. RODOS - The domestic counterpart

    International Nuclear Information System (INIS)

    Vamanu, Dan V.

    1999-01-01

    One term of reference for validly teaming up with Project RODOS (Real-Time-On-Line Decision Support System for Nuclear Emergencies in Europe) is to institutionally - contribute research initiatives geared towards emulating the RODOS functions on novel conceptual pathways, expand system's coverage of issues that are relevant in a nuclear crisis management and bring in a domestic perspective on how the system may best perform in each and every national - i.e. legal, managerial, logistic and cultural environment. On this line, one reviews the approach taken in the IFIN-HH RODOS Group to address the challenge, as well a number of representative outputs. These include: i) A phase-one, pre-RODOS, period (1990 - 1994), involving topical field orientation, feasibility demonstrations and expertise acquisition by hands-on training in environmental radiology modeling and DSS code development, the resulting products - codes in the 'APUD' and 'ACA-IFA' family, including custom versions developed by appointment of the IAEA Safety Section and AECL-Research, Ontario, Canada - being favourably reviewed by the NEA/OECD Data Bank; ii) A phase-two, upgrading and consolidation period (1994 -1996), assisted by the IAEA fellowship system and the US Government via the Nuclear Regulatory Commission in Washington, D.C, having on record an effective participation in the development of the US NRC, EPA, and DOE's 'FRMAC Assessment Manual - The Federal manual for Assessing Environmental Data during a Radiological Emergency', and the 'RTM-95 International Technical Response Manual', and the research initiative of developing a software support for the manuals' implementation - the codes 'ROBOT' (Rule-Oriented Basic Operational Tool); iii) A phase-three period (1996 - ), evolving within the RODOS framework and featuring, inter alia: (a) the application of the ROBOT concept in the development of a standalone software platform, code-named NOTEPAD for DSS support in field operations, nuclear accident drills, expert service provision on issues such as siting and health and environmental impact assessment, mainly targeting the accident source near-field; (b) a likewise experiment in the summary assessment of the far-field consequences of an atmospheric release ('QuickFIX'); (c) a research initiative in modeling the dispersion in complex topography terrains, using linearized equations of the mesoscale meteorology and heuristic concepts; (d) the development, by appointment of the Swiss Federal Institute of Technology ETH-Zurich and under the joint guidance of Institut de protection et de surete nucleaire CEA-IPSN and Kernforschungszentrum Karlsruhe, of the technical specifications and working - prototypes of the 'CONTAINMENT' module in the software package 'STEPS' (Source Term Estimation based on Plant Status). (author)

  15. Biological characteristics and clinical outcome of triple negative primary breast cancer in older women - comparison with their younger counterparts.

    Directory of Open Access Journals (Sweden)

    Binafsha M Syed

    Full Text Available Triple negative (ER, PgR and HER2 negative breast cancers (TNBCs are often considered as a poor prognostic phenotype. There is dearth of evidence showing the prevalence and biological behaviour of TNBCs in older women. This study aimed to analyse their biological characteristics in comparison with a well characterised younger series from a single centre with long term clinical follow-up. Over 37 years (1973-2010, 1,758 older (≥70 years women with early operable (<5 cm primary breast cancer were managed in a dedicated clinic and have complete clinical information available. Of these 813 patients underwent primary surgery and 575 had good quality tumour samples available for tissue microarray analysis using indirect immunohistochemistry. A total of 127 patients (22.1% had TNBCs and full biological analysis of 15 biomarkers was performed. The results were compared with those of their younger (<70 years counterparts 342 (18.9% from a previously characterised, consecutive series of primary breast cancer treated in the same unit (1986-1998. The 127 older patients with TNBCs showed lower rates of Ki67 and CK 7/8 positivity and high rates of bcl2 and CK18 positivity when compared with their younger counterparts (p<0.05. There was no significant difference in the long term clinical outcome between the two age groups, despite the fact that 47% of the younger patients had adjuvant chemotherapy, while none in the older cohort received such treatment. EGFR, axillary stage and pathological size showed prognostic significance in older women with TNBCs on univariate analysis. Despite not having received adjuvant chemotherapy, the older series had clinical outcome similar to the younger patients almost half of whom had chemotherapy. This appears to be related to other biomarkers (in addition to ER/PgR/HER2 eg Ki67, bcl2 and cytokeratins which have different expression patterns influencing prognosis.

  16. The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck

    Science.gov (United States)

    Valenti, Stefano; David; Sand, J.; Yang, Sheng; Cappellaro, Enrico; Tartaglia, Leonardo; Corsi, Alessandra; Jha, Saurabh W.; Reichart, Daniel E.; Haislip, Joshua; Kouprianov, Vladimir

    2017-10-01

    During the second observing run of the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with a binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by a coincident short gamma-ray burst trigger detected by the Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations of a sample of galaxies regularly monitored by the survey that fell within the combined LIGO+Virgo localization region and the larger Fermi gamma-ray burst error box. Here we report the discovery of a new optical transient (DLT17ck, also known as SSS17a; it has also been registered as AT 2017gfo) spatially and temporally coincident with GW170817. The photometric and spectroscopic evolution of DLT17ck is unique, with an absolute peak magnitude of M r = -15.8 ± 0.1 and an r-band decline rate of 1.1 mag day-1. This fast evolution is generically consistent with kilonova models, which have been predicted as the optical counterpart to binary neutron star coalescences. Analysis of archival DLT40 data does not show any sign of transient activity at the location of DLT17ck down to r ˜ 19 mag in the time period between 8 months and 21 days prior to GW170817. This discovery represents the beginning of a new era for multi-messenger astronomy, opening a new path by which to study and understand binary neutron star coalescences, short gamma-ray bursts, and their optical counterparts.

  17. Bimodal Long-lasting Components in Short Gamma-Ray Bursts: Promising Electromagnetic Counterparts to Neutron Star Binary Mergers

    Energy Technology Data Exchange (ETDEWEB)

    Kisaka, Shota; Sakamoto, Takanori [Department of Physics and Mathematics, Aoyama Gakuin University, Sagamihara, Kanagawa, 252-5258 (Japan); Ioka, Kunihito, E-mail: kisaka@phys.aoyama.ac.jp, E-mail: tsakamoto@phys.aoyama.ac.jp, E-mail: kunihito.ioka@yukawa.kyoto-u.ac.jp [Center for Gravitational Physics, Yukawa Institute for Theoretical Physics, Kyoto University, Kyoto 606-8502 (Japan)

    2017-09-10

    Long-lasting emission of short gamma-ray bursts (GRBs) is crucial to reveal the physical origin of the central engine as well as to detect electromagnetic (EM) counterparts to gravitational waves (GWs) from neutron star binary mergers. We investigate 65 X-ray light curves of short GRBs, which is six times more than previous studies, by combining both Swift /BAT and XRT data. The light curves are found to consist of two distinct components at >5 σ with bimodal distributions of luminosity and duration, i.e., extended (with a timescale of ≲10{sup 3} s) and plateau emission (with a timescale of ≳10{sup 3} s), which are likely the central engine activities, but not afterglows. The extended emission has an isotropic energy comparable to the prompt emission, while the plateau emission has ∼0.01–1 times this energy. Half (50%) of our sample has both components, while the other half is consistent with having both components. This leads us to conjecture that almost all short GRBs have both the extended and plateau emission. The long-lasting emission can be explained by the jets from black holes with fallback ejecta, and could power macronovae (or kilonovae) like GRB 130603B and GRB 160821B. Based on the observed properties, we quantify the detectability of EM counterparts to GWs, including the plateau emission scattered to the off-axis angle, with CALET /HXM, INTEGRAL /SPI-ACS, Fermi /GBM, MAXI /GSC, Swift /BAT, XRT, the future ISS-Lobster /WFI, Einstein Probe /WXT, and eROSITA .

  18. The Discovery of the Electromagnetic Counterpart of GW170817: Kilonova AT 2017gfo/DLT17ck

    Energy Technology Data Exchange (ETDEWEB)

    Valenti, Stefano; Yang, Sheng; Tartaglia, Leonardo [Department of Physics, University of California, 1 Shields Avenue, Davis, CA 95616-5270 (United States); Sand, David J. [Department of Astronomy/Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721-0065 (United States); Cappellaro, Enrico [INAF Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Corsi, Alessandra [Physics and Astronomy Department, Texas Tech University, Lubbock, TX 79409 (United States); Jha, Saurabh W. [Department of Physics and Astronomy, Rutgers, The State University of New Jersey, Piscataway, NJ 08854 (United States); Reichart, Daniel E.; Haislip, Joshua; Kouprianov, Vladimir [Department of Physics and Astronomy, University of North Carolina at Chapel Hill, Chapel Hill, NC 27599 (United States)

    2017-10-20

    During the second observing run of the Laser Interferometer Gravitational-wave Observatory (LIGO) and Virgo Interferometer, a gravitational-wave signal consistent with a binary neutron star coalescence was detected on 2017 August 17th (GW170817), quickly followed by a coincident short gamma-ray burst trigger detected by the Fermi satellite. The Distance Less Than 40 (DLT40) Mpc supernova search performed pointed follow-up observations of a sample of galaxies regularly monitored by the survey that fell within the combined LIGO+Virgo localization region and the larger Fermi gamma-ray burst error box. Here we report the discovery of a new optical transient (DLT17ck, also known as SSS17a; it has also been registered as AT 2017gfo) spatially and temporally coincident with GW170817. The photometric and spectroscopic evolution of DLT17ck is unique, with an absolute peak magnitude of M {sub r} = −15.8 ± 0.1 and an r -band decline rate of 1.1 mag day{sup −1}. This fast evolution is generically consistent with kilonova models, which have been predicted as the optical counterpart to binary neutron star coalescences. Analysis of archival DLT40 data does not show any sign of transient activity at the location of DLT17ck down to r ∼ 19 mag in the time period between 8 months and 21 days prior to GW170817. This discovery represents the beginning of a new era for multi-messenger astronomy, opening a new path by which to study and understand binary neutron star coalescences, short gamma-ray bursts, and their optical counterparts.

  19. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta

    Science.gov (United States)

    Alexander, K. D.; Berger, E.; Fong, W.; Williams, P. K. G.; Guidorzi, C.; Margutti, R.; Metzger, B. D.; Annis, J.; Blanchard, P. K.; Brout, D.; Brown, D. A.; Chen, H.-Y.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Eftekhari, T.; Frieman, J.; Holz, D. E.; Nicholl, M.; Rest, A.; Sako, M.; Soares-Santos, M.; Villar, V. A.

    2017-10-01

    We present Very Large Array (VLA) and Atacama Large Millimeter/submillimeter Array (ALMA) radio observations of GW170817, the first Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo gravitational wave (GW) event from a binary neutron star merger and the first GW event with an electromagnetic (EM) counterpart. Our data include the first observations following the discovery of the optical transient at both the centimeter (13.7 hr post-merger) and millimeter (2.41 days post-merger) bands. We detect faint emission at 6 GHz at 19.47 and 39.23 days after the merger, but not in an earlier observation at 2.46 days. We do not detect cm/mm emission at the position of the optical counterpart at frequencies of 10-97.5 GHz at times ranging from 0.6 to 30 days post-merger, ruling out an on-axis short gamma-ray burst (SGRB) for energies ≳ {10}48 erg. For fiducial SGRB parameters, our limits require an observer viewer angle of ≳20°. The radio and X-ray data can be jointly explained as the afterglow emission from an SGRB with a jet energy of ˜ {10}49{--}{10}50 erg that exploded in a uniform density environment with n˜ {10}-4{--}{10}-2 cm-3, viewed at an angle of ˜20°-40° from the jet axis. Using the results of our light curve and spectral modeling, in conjunction with the inference of the circumbinary density, we predict the emergence of late-time radio emission from the deceleration of the kilonova (KN) ejecta on a timescale of ˜5-10 years that will remain detectable for decades with next-generation radio facilities, making GW170817 a compelling target for long-term radio monitoring.

  20. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VI. Radio Constraints on a Relativistic Jet and Predictions for Late-time Emission from the Kilonova Ejecta

    Energy Technology Data Exchange (ETDEWEB)

    Alexander, K. D.; Berger, E.; Fong, W.; Williams, P. K. G.; Guidorzi, C.; Margutti, R.; Metzger, B. D.; Annis, J.; Blanchard, P. K.; Brout, D.; Brown, D. A.; Chen, H. -Y.; Chornock, R.; Cowperthwaite, P. S.; Drout, M.; Eftekhari, T.; Frieman, J.; Holz, D. E.; Nicholl, M.; Rest, A.; Sako, M.; Soares-Santos, M.; Villar, V. A.

    2017-10-16

    We present Very Large Array (VLA) and Atacama Large Millimeter/sub-millimeter Array ALMA radio observations of GW\\,170817, the first Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo gravitational wave (GW) event from a binary neutron star merger and the first GW event with an electromagnetic (EM) counterpart. Our data include the first observations following the discovery of the optical transient at both the centimeter ($13.7$ hours post merger) and millimeter ($2.41$ days post merger) bands. We detect faint emission at 6 GHz at 19.47 and 39.23 days after the merger, but not in an earlier observation at 2.46 d. We do not detect cm/mm emission at the position of the optical counterpart at frequencies of 10-97.5 GHz at times ranging from 0.6 to 30 days post merger, ruling out an on-axis short gamma-ray burst (SGRB) for energies $\\gtrsim 10^{48}$ erg. For fiducial SGRB parameters, our limits require an observer viewer angle of $\\gtrsim 20^{\\circ}$. The radio and X-ray data can be jointly explained as the afterglow emission from an SGRB with a jet energy of $\\sim 10^{49}-10^{50}$ erg that exploded in a uniform density environment with $n\\sim 10^{-4}-10^{-2}$ cm$^{-3}$, viewed at an angle of $\\sim 20^{\\circ}-40^{\\circ}$ from the jet axis. Using the results of our light curve and spectral modeling, in conjunction with the inference of the circumbinary density, we predict the emergence of late-time radio emission from the deceleration of the kilonova (KN) ejecta on a timescale of $\\sim 5-10$ years that will remain detectable for decades with next-generation radio facilities, making GW\\,170817 a compelling target for long-term radio monitoring.

  1. Semiclassical Theory of Spectral Rigidity

    Science.gov (United States)

    Berry, M. V.

    1985-08-01

    The spectral rigidity Δ(L) of a set of quantal energy levels is the mean square deviation of the spectral staircase from the straight line that best fits it over a range of L mean level spacings. In the semiclassical limit (hslash-> 0), formulae are obtained giving Δ(L) as a sum over classical periodic orbits. When L ~= Lmax, where Lmax ~ hslash-(N-1) for a system of N freedoms, Δ(L) is shown to display the following universal behaviour as a result of properties of very long classical orbits: if the system is classically integrable (all periodic orbits filling tori), Δ(L) = 1/15L (as in an uncorrelated (Poisson) eigenvalue sequence); if the system is classically chaotic (all periodic orbits isolated and unstable) and has no symmetry, Δ(L) = ln L/2π^2 + D if 1 ~= L ~= Lmax (as in the gaussian unitary ensemble of random-matrix theory); if the system is chaotic and has time-reversal symmetry, Δ(L) = ln L/π^2 + E if 1 ~= L ~= Lmax (as in the gaussian orthogonal ensemble). When L >> Lmax, Δ(L) saturates non-universally at a value, determined by short classical orbits, of order hslash-(N-1) for integrable systems and ln (hslash-1) for chaotic systems. These results are obtained by using the periodic-orbit expansion for the spectral density, together with classical sum rules for the intensities of long orbits and a semiclassical sum rule restricting the manner in which their contributions interfere. For two examples Δ(L) is studied in detail: the rectangular billiard (integrable), and the Riemann zeta function (assuming its zeros to be the eigenvalues of an unknown quantum system whose unknown classical limit is chaotic).

  2. Planck 2013 results. IX. HFI spectral response

    CERN Document Server

    Ade, P A R; Armitage-Caplan, C; Arnaud, M; Ashdown, M; Atrio-Barandela, F; Aumont, J; Baccigalupi, C; Banday, A J; Barreiro, R B; Battaner, E; Benabed, K; Benoît, A; Benoit-Lévy, A; Bernard, J -P; Bersanelli, M; Bielewicz, P; Bobin, J; Bock, J J; Bond, J R; Borrill, J; Bouchet, F R; Boulanger, F; Bridges, M; Bucher, M; Burigana, C; Cardoso, J -F; Catalano, A; Challinor, A; Chamballu, A; Chary, R -R; Chen, X; Chiang, L -Y; Chiang, H C; Christensen, P R; Church, S; Clements, D L; Colombi, S; Colombo, L P L; Combet, C; Comis, B; Couchot, F; Coulais, A; Crill, B P; Curto, A; Cuttaia, F; Danese, L; Davies, R D; de Bernardis, P; de Rosa, A; de Zotti, G; Delabrouille, J; Delouis, J -M; Désert, F -X; Dickinson, C; Diego, J M; Dole, H; Donzelli, S; Doré, O; Douspis, M; Dupac, X; Efstathiou, G; Enßlin, T A; Eriksen, H K; Falgarone, E; Finelli, F; Forni, O; Frailis, M; Franceschi, E; Galeotta, S; Ganga, K; Giard, M; Giraud-Héraud, Y; González-Nuevo, J; Górski, K M; Gratton, S; Gregorio, A; Gruppuso, A; Hansen, F K; Hanson, D; Harrison, D; Henrot-Versillé, S; Hernández-Monteagudo, C; Herranz, D; Hildebrandt, S R; Hivon, E; Hobson, M; Holmes, W A; Hornstrup, A; Hovest, W; Huffenberger, K M; Hurier, G; Jaffe, T R; Jaffe, A H; Jones, W C; Juvela, M; Keihänen, E; Keskitalo, R; Kisner, T S; Kneissl, R; Knoche, J; Knox, L; Kunz, M; Kurki-Suonio, H; Lagache, G; Lamarre, J -M; Lasenby, A; Laureijs, R J; Lawrence, C R; Leahy, J P; Leonardi, R; Leroy, C; Lesgourgues, J; Liguori, M; Lilje, P B; Linden-Vørnle, M; López-Caniego, M; Lubin, P M; Macías-Pérez, J F; Maffei, B; Mandolesi, N; Maris, M; Marshall, D J; Martin, P G; Martínez-González, E; Masi, S; Matarrese, S; Matthai, F; Mazzotta, P; McGehee, P; Melchiorri, A; Mendes, L; Mennella, A; Migliaccio, M; Mitra, S; Miville-Deschênes, M -A; Moneti, A; Montier, L; Morgante, G; Mortlock, D; Munshi, D; Murphy, J A; Naselsky, P; Nati, F; Natoli, P; Netterfield, C B; Nørgaard-Nielsen, H U; North, C; Noviello, F; Novikov, D; Novikov, I; Osborne, S; Oxborrow, C A; Paci, F; Pagano, L; Pajot, F; Paoletti, D; Pasian, F; Patanchon, G; Perdereau, O; Perotto, L; Perrotta, F; Piacentini, F; Piat, M; Pierpaoli, E; Pietrobon, D; Plaszczynski, S; Pointecouteau, E; Polenta, G; Ponthieu, N; Popa, L; Poutanen, T; Pratt, G W; Prézeau, G; Prunet, S; Puget, J -L; Rachen, J P; Reinecke, M; Remazeilles, M; Renault, C; Ricciardi, S; Riller, T; Ristorcelli, I; Rocha, G; Rosset, C; Roudier, G; Rusholme, B; Santos, D; Savini, G; Shellard, E P S; Spencer, L D; Starck, J -L; Stolyarov, V; Stompor, R; Sudiwala, R; Sureau, F; Sutton, D; Suur-Uski, A -S; Sygnet, J -F; Tauber, J A; Tavagnacco, D; Terenzi, L; Tomasi, M; Tristram, M; Tucci, M; Umana, G; Valenziano, L; Valiviita, J; Van Tent, B; Vielva, P; Villa, F; Vittorio, N; Wade, L A; Wandelt, B D; Yvon, D; Zacchei, A; Zonca, A

    2014-01-01

    The Planck High Frequency Instrument (HFI) spectral response was determined through a series of ground based tests conducted with the HFI focal plane in a cryogenic environment prior to launch. The main goal of the spectral transmission tests was to measure the relative spectral response (including out-of-band signal rejection) of all HFI detectors. This was determined by measuring the output of a continuously scanned Fourier transform spectrometer coupled with all HFI detectors. As there is no on-board spectrometer within HFI, the ground-based spectral response experiments provide the definitive data set for the relative spectral calibration of the HFI. The spectral response of the HFI is used in Planck data analysis and component separation, this includes extraction of CO emission observed within Planck bands, dust emission, Sunyaev-Zeldovich sources, and intensity to polarization leakage. The HFI spectral response data have also been used to provide unit conversion and colour correction analysis tools. Ver...

  3. Spectral fluctuations and zeta functions

    International Nuclear Information System (INIS)

    Balazs, N.L.; Schmit, C.; Voros, A.

    1987-01-01

    The study theoretically and numerically the role of the fluctuations of eigenvalue spectra {μ/sub n} in a particular analytical continuation process applied to the (generalized) zeta function Z(s) = Σ/sub n/μ/sub n//sup -s/ for s large and positive. A particularly interesting example is the spectrum of the Laplacian on a triangular domain which tessellates a compact surface of constant negative curvature (of genus two). The authors indeed find that the fluctuations restrict the abscissa of convergence, and also affect the rate of convergence. This then initiates a new approach to the exploration of spectral fluctuations through the convergence of analytical continuation processes

  4. XMMFITCAT-Z: The enhanced XMM-Newton spectral-fit database by the inclusion of photometric redshifts

    Science.gov (United States)

    Corral, A.; Georgantopoulos, I.; Mountrichas, G.; Ruiz, A.; Carrera, F.; Fotopoulou, S.; Watson, M.; Rosen, S.; Webb, N.

    2017-10-01

    I will present XMMFITCAT-Z, an unique tool for the astronomical community to construct large and representative samples of X-ray sources by selecting them according to their spectral properties. XMMFITCAT-Z is an enhanced version of XMMFITCAT, the XMM-Newton spectral-fit database, which contains automated spectral-fitting results for the X-ray sources within the XMM-Newton serendipitous source catalogue for which spectral data were pipe-line extracted, ˜ 120,000 source detetections corresponding to ˜ 80,000 unique sources. XMMFITCAT-Z is aimed to the derivation of photometric redshifts and redshift-dependent spectral fits by using up to 10 photometric points, from the optical to the mid-infrared, and machine learnig techniques. We have already made use of the photometric data from the SDSS, UKIDSS, 2MASS and WISE surveys to evaluate the reliability of our photometric redshifts, and we are currently implementing the recently released data from the Pan-STARRS survey to further increase the number of X-ray sources with optical counterparts. The final database will contain photometric redshifts for more than 40,000 extragalactic X-ray sources, and redshift-dependent spectral fits for those with extracted spectra.

  5. Efficient single-pixel multispectral imaging via non-mechanical spatio-spectral modulation.

    Science.gov (United States)

    Li, Ziwei; Suo, Jinli; Hu, Xuemei; Deng, Chao; Fan, Jingtao; Dai, Qionghai

    2017-01-27

    Combining spectral imaging with compressive sensing (CS) enables efficient data acquisition by fully utilizing the intrinsic redundancies in natural images. Current compressive multispectral imagers, which are mostly based on array sensors (e.g, CCD or CMOS), suffer from limited spectral range and relatively low photon efficiency. To address these issues, this paper reports a multispectral imaging scheme with a single-pixel detector. Inspired by the spatial resolution redundancy of current spatial light modulators (SLMs) relative to the target reconstruction, we design an all-optical spectral splitting device to spatially split the light emitted from the object into several counterparts with different spectrums. Separated spectral channels are spatially modulated simultaneously with individual codes by an SLM. This no-moving-part modulation ensures a stable and fast system, and the spatial multiplexing ensures an efficient acquisition. A proof-of-concept setup is built and validated for 8-channel multispectral imaging within 420~720 nm wavelength range on both macro and micro objects, showing a potential for efficient multispectral imager in macroscopic and biomedical applications.

  6. Auditory evoked fields elicited by spectral, temporal, and spectral-temporal changes in human cerebral cortex

    Directory of Open Access Journals (Sweden)

    Hidehiko eOkamoto

    2012-05-01

    Full Text Available Natural sounds contain complex spectral components, which are temporally modulated as time-varying signals. Recent studies have suggested that the auditory system encodes spectral and temporal sound information differently. However, it remains unresolved how the human brain processes sounds containing both spectral and temporal changes. In the present study, we investigated human auditory evoked responses elicited by spectral, temporal, and spectral-temporal sound changes by means of magnetoencephalography (MEG. The auditory evoked responses elicited by the spectral-temporal change were very similar to those elicited by the spectral change, but those elicited by the temporal change were delayed by 30 – 50 ms and differed from the others in morphology. The results suggest that human brain responses corresponding to spectral sound changes precede those corresponding to temporal sound changes, even when the spectral and temporal changes occur simultaneously.

  7. Light distribution system comprising spectral conversion means

    DEFF Research Database (Denmark)

    2012-01-01

    System (200, 300) for the distribution of white light, having a supply side (201, 301, 401) and a delivery side (202, 302, 402), the system being configured for guiding light with a multitude of visible wavelengths in a propagation direction P from the supply side to the distribution side...... fibre being operationally connected to the spectral conversion fibre having a length extending from an input end (221, 321)to an output end (222, 322), the spectral conversion fibre comprising a photoluminescent agent (511, 611, 711) for converting light of a first wavelength to light of a second......, longer wavelength,a spectral conversion characteristics of the spectral conversion fibre being essentially determined by the spectral absorption and emission properties of the photoluminescent agent, the amount of photo- luminescent agent,and the distribution of the photoluminescent agent in the spectral...

  8. Spectral functions in mathematics and physics

    CERN Document Server

    Kirsten, Klaus

    2002-01-01

    The literature on the spectral analysis of second order elliptic differential operators contains a great deal of information on the spectral functions for explicitly known spectra. The same is not true, however, for situations where the spectra are not explicitly known. Over the last several years, the author and his colleagues have developed new, innovative methods for the exact analysis of a variety of spectral functions occurring in spectral geometry and under external conditions in statistical mechanics and quantum field theory. Spectral Functions in Mathematics and Physics presents a detailed overview of these advances. The author develops and applies methods for analyzing determinants arising when the external conditions originate from the Casimir effect, dielectric media, scalar backgrounds, and magnetic backgrounds. The zeta function underlies all of these techniques, and the book begins by deriving its basic properties and relations to the spectral functions. The author then uses those relations to d...

  9. Quantitative spectral comparison by weighted spectral difference for protein higher order structure confirmation.

    Science.gov (United States)

    Dinh, Nikita N; Winn, Bradley C; Arthur, Kelly K; Gabrielson, John P

    2014-11-01

    Previously, different approaches of spectral comparison were evaluated, and the spectral difference (SD) method was shown to be valuable for its linearity with spectral changes and its independence on data spacing (Anal. Biochem. 434 (2013) 153-165). In this note, we present an enhancement of the SD calculation, referred to as the "weighted spectral difference" (WSD), by implementing a weighting function based on relative signal magnitude. While maintaining the advantages of the SD method, WSD improves the method sensitivity to spectral changes and tolerance for baseline inclusion. Furthermore, a generalized formula is presented to unify further development of approaches to quantify spectral difference. Copyright © 2014 Elsevier Inc. All rights reserved.

  10. Radiometric sensitivity contrast metrics for spectral remote sensors

    Science.gov (United States)

    Silny, John F.; Zellinger, Louis

    2017-08-01

    The calculation, interpretation, and implications of radiometric sensitivity metrics for Earth-observing multispectral and hyperspectral imaging sensors are discussed. The most commonly used sensor performance metric is signal-to-noise ratio, from which additional noise equivalent quantities can be computed, including noise equivalent spectral radiance (NESR), noise equivalent delta reflectance (NEΔρ), noise equivalent delta emittance (NEΔɛ), and noise equivalent delta temperature (NEΔT). For hyperspectral sensors, these metrics are typically calculated from an at-aperture radiance (typically generated by MODTRAN) that includes both target radiance and nontarget (atmosphere and background) radiance. Unfortunately, these calculations treat the entire at-aperture radiance as the desired signal, even when the target radiance is only a fraction of the total (such as when sensing through a long or optically dense atmospheric path). To overcome this limitation, an augmented set of metrics based on a contrast signal-to-noise ratio, including their noise equivalent counterparts (CNESR, CNEΔρ, CNEΔɛ, and CNEΔT), is developed. These contrast metrics better quantify sensor performance in an operational environment that includes remote sensing through the atmosphere.

  11. Spectral properties of nuclear matter

    International Nuclear Information System (INIS)

    Bozek, P

    2006-01-01

    We review self-consistent spectral methods for nuclear matter calculations. The in-medium T-matrix approach is conserving and thermodynamically consistent. It gives both the global and the single-particle properties the system. The T-matrix approximation allows to address the pairing phenomenon in cold nuclear matter. A generalization of nuclear matter calculations to the super.uid phase is discussed and numerical results are presented for this case. The linear response of a correlated system going beyond the Hartree-Fock+ Random-Phase-Approximation (RPA) scheme is studied. The polarization is obtained by solving a consistent Bethe-Salpeter (BS) equation for the coupling of dressed nucleons to an external field. We find that multipair contributions are important for the spin(isospin) response when the interaction is spin(isospin) dependent

  12. Signature spectrale des grains interstellaires.

    Science.gov (United States)

    Léger, A.

    Notre connaissance de la nature des grains interstellaires reposait sur un nombre très restreint de signatures spectrales dans la courbe d'extinction du milieu interstellaire. Une information considérable est contenue dans les 40 bandes interstellaires diffuses dans le visible, mais reste inexploitée. L'interprétation récente des cinq bandes IR en émission, en terme de molécules d'hydrocarbures aromatiques polycycliques, est développée. Elle permet l'utilisation d'une information spectroscopique comparable, à elle seule, à ce sur quoi était basée jusqu'alors notre connaissance de la matière interstellaire condensée. Différentes implications de cette mise en évidence sont proposées.

  13. Elementary principles of spectral distributions

    International Nuclear Information System (INIS)

    French, J.B.

    1980-01-01

    It is a common observation that as we add particles, one by one, to a simple system, things get steadily more and more complicated. For example if the system is describable in shell-model terms, i.e., with a model space in which m particles are distributed over N single-particle states, then as long as m << N, the dimensionality increases rapidly with particle number. On the other hand, for the usual (1 + 2)-body Hamiltonian, the (m greater than or equal to 2)-particle spectrum and wave functions are determined by operators defined in the one-particle space (for the single-particle energies) and the two-particle space (for the interactions). We may say then that the input information becomes more and more fragmented as the particle number increases, the fixed amount of information being distributed over more and more matrix elements. On the other hand there arise also new simplicities whose origin is connected with the operation of statistical laws. There is a macroscopic simplicity corresponding to the fact that the smoothed spectrum takes on a characteristic shape defined by a few parameters (low-order moments) of the spectrum. There is a microscopic simplicity corresponding to a remarkable spectral rigidity which extends over the entire spectrum and guarantees us that the fluctuations from uniformity in the spectrum are small and in many cases carry little information. The purpose of spectral-distribution theory, as applied to these problems, is to deal with the complexities by taking advantage of the simplicities

  14. Buckling feedback of the spectral calculations

    International Nuclear Information System (INIS)

    Jing Xingqing; Shan Wenzhi; Luo Jingyu

    1992-01-01

    This paper studies the problems about buckling feedback of spectral calculations in physical calculations of the reactor and presents a useful method by which the buckling feedback of spectral calculations is implemented. The effect of the buckling feedback in spectra and the broad group cross section, convergence of buckling feedback iteration and the effect of the spectral zones dividing are discussed in the calculations. This method has been used for the physical design of HTR-10 MW Test Module

  15. Spectral mapping theorems a bluffer's guide

    CERN Document Server

    Harte, Robin

    2014-01-01

    Written by an author who was at the forefront of developments in multi-variable spectral theory during the seventies and the eighties, this guide sets out to describe in detail the spectral mapping theorem in one, several and many variables. The basic algebraic systems – semigroups, rings and linear algebras – are summarised, and then topological-algebraic systems, including Banach algebras, to set up the basic language of algebra and analysis. Spectral Mapping Theorems is written in an easy-to-read and engaging manner and will be useful for both the beginner and expert. It will be of great importance to researchers and postgraduates studying spectral theory.

  16. Spectrally-engineered solar thermal photovoltaic devices

    Energy Technology Data Exchange (ETDEWEB)

    Lenert, Andrej; Bierman, David; Chan, Walker; Celanovic, Ivan; Soljacic, Marin; Wang, Evelyn N.; Nam, Young Suk; McEnaney, Kenneth; Kraemer, Daniel; Chen, Gang

    2018-03-27

    A solar thermal photovoltaic device, and method of forming same, includes a solar absorber and a spectrally selective emitter formed on either side of a thermally conductive substrate. The solar absorber is configured to absorb incident solar radiation. The solar absorber and the spectrally selective emitter are configured with an optimized emitter-to-absorber area ratio. The solar thermal photovoltaic device also includes a photovoltaic cell in thermal communication with the spectrally selective emitter. The spectrally selective emitter is configured to permit high emittance for energies above a bandgap of the photovoltaic cell and configured to permit low emittance for energies below the bandgap.

  17. Global and local aspects of spectral actions

    Science.gov (United States)

    Iochum, B.; Levy, C.; Vassilevich, D. V.

    2012-09-01

    The principal object in noncommutative geometry is the spectral triple consisting of an algebra {A}, a Hilbert space {H} and a Dirac operator {D}. Field theories are incorporated in this approach by the spectral action principle, which sets the field theory action to Tr\\,f( {D}^2/\\Lambda ^2), where f is a real function such that the trace exists and Λ is a cutoff scale. In the low-energy (weak-field) limit, the spectral action reproduces reasonably well the known physics including the standard model. However, not much is known about the spectral action beyond the low-energy approximation. In this paper, after an extensive introduction to spectral triples and spectral actions, we study various expansions of the spectral actions (exemplified by the heat kernel). We derive the convergence criteria. For a commutative spectral triple, we compute the heat kernel on the torus up to the second order in gauge connection and consider limiting cases. This article is part of a special issue of Journal of Physics A: Mathematical and Theoretical in honour of Stuart Dowker’s 75th birthday devoted to ‘Applications of zeta functions and other spectral functions in mathematics and physics’.

  18. Kilonova from post-merger ejecta as an optical and near-Infrared counterpart of GW170817

    Science.gov (United States)

    Tanaka, Masaomi; Utsumi, Yousuke; Mazzali, Paolo A.; Tominaga, Nozomu; Yoshida, Michitoshi; Sekiguchi, Yuichiro; Morokuma, Tomoki; Motohara, Kentaro; Ohta, Kouji; Kawabata, Koji S.; Abe, Fumio; Aoki, Kentaro; Asakura, Yuichiro; Baar, Stefan; Barway, Sudhanshu; Bond, Ian A.; Doi, Mamoru; Fujiyoshi, Takuya; Furusawa, Hisanori; Honda, Satoshi; Itoh, Yoichi; Kawabata, Miho; Kawai, Nobuyuki; Kim, Ji Hoon; Lee, Chien-Hsiu; Miyazaki, Shota; Morihana, Kumiko; Nagashima, Hiroki; Nagayama, Takahiro; Nakaoka, Tatsuya; Nakata, Fumiaki; Ohsawa, Ryou; Ohshima, Tomohito; Okita, Hirofumi; Saito, Tomoki; Sumi, Takahiro; Tajitsu, Akito; Takahashi, Jun; Takayama, Masaki; Tamura, Yoichi; Tanaka, Ichi; Terai, Tsuyoshi; Tristram, Paul J.; Yasuda, Naoki; Zenko, Tetsuya

    2017-12-01

    Recent detection of gravitational waves from a neutron star (NS) merger event GW170817 and identification of an electromagnetic counterpart provide a unique opportunity to study the physical processes in NS mergers. To derive properties of ejected material from the NS merger, we perform radiative transfer simulations of kilonova, optical and near-infrared emissions powered by radioactive decays of r-process nuclei synthesized in the merger. We find that the observed near-infrared emission lasting for >10 d is explained by 0.03 M⊙ of ejecta containing lanthanide elements. However, the blue optical component observed at the initial phases requires an ejecta component with a relatively high electron fraction (Ye). We show that both optical and near-infrared emissions are simultaneously reproduced by the ejecta with a medium Ye of ˜0.25. We suggest that a dominant component powering the emission is post-merger ejecta, which exhibits that the mass ejection after the first dynamical ejection is quite efficient. Our results indicate that NS mergers synthesize a wide range of r-process elements and strengthen the hypothesis that NS mergers are the origin of r-process elements in the Universe.

  19. Hubble Space Telescope observations of the optical counterpart to a ultra-compact high-velocity cloud

    Science.gov (United States)

    Sand, David J.

    2017-01-01

    As part of a comprehensive archival search for optical counterparts to ultra-compact high-velocity clouds (UCHVCs), our team has uncovered five Local Volume dwarf galaxies, two of which were not previously known. Among these was AGC 226067, also known as ALFALFA-Dw1, which appeared to be made up of several HI and blue optical clumps based on ground-based data, with at least one HII region. Here we present Hubble Space Telescope Advanced Camera for Surveys data of AGC 226067. The data show that AGC 226067 is made up of a ~7-30 Myr old stellar population with a [Fe/H]~-0.6. Further, there is no evidence for an old stellar population associated with the system, down to a limit of MV>-8. Based on this and the position of AGC 226067 in the outskirts of the M86 subgroup of the Virgo cluster we present various arguments for the origin of this strange stellar system.

  20. A Dark Energy Camera Search for an Optical Counterpart to the First Advanced LIGO Gravitational Wave Event GW150914

    Science.gov (United States)

    Soares-Santos, M.; Kessler, R.; Burger, E.; Annis, J.; Brout, D.; Buckley-Geer, E.; Chen, H.; Cowperthwaite, P. S.; Diehl, H.T.; Doctor, Z.; hide

    2016-01-01

    We report the results of a deep search for an optical counterpart to the gravitational wave (GW) event GW150914, the first trigger from the Advanced LIGO GW detectors. We used the Dark Energy Camera (DECam) to image a 102 deg(exp 2) area, corresponding to 38% of the initial trigger high-probability sky region and to 11% of the revised high-probability region. We observed in the i and z bands at 4-5, 7, and 24 days after the trigger. The median 5(sigma) point-source limiting magnitudes of our search images are i = 22.5 and z = 21.8 mag. We processed the images through a difference-imaging pipeline using templates from pre-existing Dark Energy Survey data and publicly available DECam data. Due to missing template observations and other losses, our effective search area subtends 40 deg(exp 2), corresponding to a 12% total probability in the initial map and 3% in the final map. In this area, we search for objects that decline significantly between days 4-5 and day 7, and are undetectable by day 24, finding none to typical magnitude limits of i = 21.5, 21.1, 20.1 for object colors (i-z)= 1, 0, -1, respectively. Our search demonstrates the feasibility of a dedicated search program with DECam and bodes well for future research in this emerging field.

  1. Thermodynamic Stability of Ice II and Its Hydrogen-Disordered Counterpart: Role of Zero-Point Energy.

    Science.gov (United States)

    Nakamura, Tatsuya; Matsumoto, Masakazu; Yagasaki, Takuma; Tanaka, Hideki

    2016-03-03

    We investigate why no hydrogen-disordered form of ice II has been found in nature despite the fact that most of hydrogen-ordered ices have hydrogen-disordered counterparts. The thermodynamic stability of a set of hydrogen-ordered ice II variants relative to ice II is evaluated theoretically. It is found that ice II is more stable than the disordered variants so generated as to satisfy the simple ice rule due to the lower zero-point energy as well as the pair interaction energy. The residual entropy of the disordered ice II phase gradually compensates the unfavorable free energy with increasing temperature. The crossover, however, occurs at a high temperature well above the melting point of ice III. Consequently, the hydrogen-disordered phase does not exist in nature. The thermodynamic stability of partially hydrogen-disordered ices is also scrutinized by examining the free-energy components of several variants obtained by systematic inversion of OH directions in ice II. The potential energy of one variant is lower than that of the ice II structure, but its Gibbs free energy is slightly higher than that of ice II due to the zero-point energy. The slight difference in the thermodynamic stability leaves the possibility of the partial hydrogen-disorder in real ice II.

  2. UNVEILING THE NATURE OF THE UNIDENTIFIED GAMMA-RAY SOURCES. III. GAMMA-RAY BLAZAR-LIKE COUNTERPARTS AT LOW RADIO FREQUENCIES

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F.; Funk, S. [SLAC National Laboratory and Kavli Institute for Particle Astrophysics and Cosmology, 2575 Sand Hill Road, Menlo Park, CA 94025 (United States); D' Abrusco, R.; Paggi, A. [Harvard-Smithsonian Astrophysical Observatory, 60 Garden Street, Cambridge, MA 02138 (United States); Giroletti, M. [INAF Istituto di Radioastronomia, via Gobetti 101, I-40129 Bologna (Italy); Masetti, N. [INAF-Istituto di Astrofisica Spaziale e Fisica Cosmica di Bologna, via Gobetti 101, I-40129 Bologna (Italy); Tosti, G. [Dipartimento di Fisica, Universita degli Studi di Perugia, I-06123 Perugia (Italy); Nori, M. [Department of Physics and Astronomy, University of Bologna, viale Berti Pichat 6/2, I-40127 Bologna (Italy)

    2013-07-01

    About one-third of the {gamma}-ray sources listed in the second Fermi Large Area Telescope catalog (2FGL) have no firmly established counterpart at lower energies and so are classified as unidentified gamma-ray sources (UGSs). Here, we propose a new approach to find candidate counterparts for the UGSs based on the 325 MHz radio survey performed with the Westerbork Synthesis Radio Telescope in the northern hemisphere. First, we investigate the low-frequency radio properties of blazars, the largest known population of {gamma}-ray sources; then we search for sources with similar radio properties combining the information derived from the Westerbork Northern Sky Survey (WENSS) with those of the NRAO Very Large Array Sky Survey. We present a list of candidate counterparts for 32 UGSs with at least one counterpart in the WENSS. We also performed an extensive research in the literature to look for infrared and optical counterparts of the {gamma}-ray blazar candidates selected using the low-frequency radio observations to confirm their nature. On the basis of our multifrequency research, we identify 23 new {gamma}-ray blazar candidates out of the 32 UGSs investigated. Comparison with previous results on the UGSs is also presented. Finally, we speculate on the advantages of using low-frequency radio observations to associate UGSs and to search for {gamma}-ray pulsar candidates.

  3. Spectral filtering for plant production

    Science.gov (United States)

    Young, Roy E.; Mcmahon, Margaret J.; Rajapakse, Nihal C.; Decoteau, Dennis R.

    1994-01-01

    Both plants and animals have one general commonality in their perception of light. They both are sensitive primarily to the 400 to 700 nm wavelength portion of the electromagnetic spectrum. This is referred to as the visible spectrum for animals and as the photosynthetically active radiation (PAR) spectrum for plants. Within this portion of the spectrum, animals perceive colors. Relatively recently it has been learned that within this same spectral range plants also demonstrate varying responses at different wavelengths, somewhat analogous to the definition of various colors at specific wavelengths. Although invisible to the human eye, portions of the electromagnetic spectrum on either side of the visible range are relatively inactive photosynthetically but have been found to influence important biological functions. These portions include the ultraviolet (UV approximately equal to 280-400 nm) and the far-red (FR approximately equal to 700-800 nm). The basic photoreceptor of plants for photosynthesis is chlorophyll. It serves to capture radiant energy which combined with carbon dioxide and water produces oxygen and assimulated carbon, used for the synthesis of cell wall polysaccarides, proteins, membrane lipids and other cellular constituents. The energy and carbon building blocks of photosynthesis sustain growth of plants. On the other hand, however, there are other photoreceptors, or pigments, that function as signal transducers to provide information that controls many physiological and morphological responses of how a plant grows. Known photomorphogenic receptors include phytochrome (the red/far-red sensor in the narrow bands of 655-665 nm and 725-735 nm ranges, respectively) and 'cryptochrome' (the hypothetical UV-B sensor in the 280-320 nm range). Since the USDA team of W. L. Butler, S. B. Hendricks, H. A. Borthwick, H. A. Siegleman and K. Norris in Beltsville, MD detected by spectroscopy, extracted and identified phytochrome as a protein in the 1950's, many

  4. A Black Hole Spectral Signature

    Science.gov (United States)

    Titarchuk, Lev; Laurent, Philippe

    2000-03-01

    An accreting black hole is, by definition, characterized by the drain. Namely, the matter falls into a black hole much the same way as water disappears down a drain matter goes in and nothing comes out. As this can only happen in a black hole, it provides a way to see ``a black hole'', an unique observational signature. The accretion proceeds almost in a free-fall manner close to the black hole horizon, where the strong gravitational field dominates the pressure forces. In this paper we present analytical calculations and Monte-Carlo simulations of the specific features of X-ray spectra formed as a result of upscattering of the soft (disk) photons in the converging inflow (CI) into the black hole. The full relativistic treatment has been implemented to reproduce these spectra. We show that spectra in the soft state of black hole systems (BHS) can be described as the sum of a thermal (disk) component and the convolution of some fraction of this component with the CI upscattering spread (Greens) function. The latter boosted photon component is seen as an extended power-law at energies much higher than the characteristic energy of the soft photons. We demonstrate the stability of the power spectral index over a wide range of the plasma temperature 0 - 10 keV and mass accretion rates (higher than 2 in Eddington units). We also demonstrate that the sharp high energy cutoff occurs at energies of 200-400 keV which are related to the average energy of electrons mec2 impinging upon the event horizon. The spectrum is practically identical to the standard thermal Comptonization spectrum when the CI plasma temperature is getting of order of 50 keV (the typical ones for the hard state of BHS). In this case one can see the effect of the bulk motion only at high energies where there is an excess in the CI spectrum with respect to the pure thermal one. Furthermore we demonstrate that the change of spectral shapes from the soft X-ray state to the hard X-ray state is clearly to be

  5. Spectral affinity in protein networks.

    Science.gov (United States)

    Voevodski, Konstantin; Teng, Shang-Hua; Xia, Yu

    2009-11-29

    Protein-protein interaction (PPI) networks enable us to better understand the functional organization of the proteome. We can learn a lot about a particular protein by querying its neighborhood in a PPI network to find proteins with similar function. A spectral approach that considers random walks between nodes of interest is particularly useful in evaluating closeness in PPI networks. Spectral measures of closeness are more robust to noise in the data and are more precise than simpler methods based on edge density and shortest path length. We develop a novel affinity measure for pairs of proteins in PPI networks, which uses personalized PageRank, a random walk based method used in context-sensitive search on the Web. Our measure of closeness, which we call PageRank Affinity, is proportional to the number of times the smaller-degree protein is visited in a random walk that restarts at the larger-degree protein. PageRank considers paths of all lengths in a network, therefore PageRank Affinity is a precise measure that is robust to noise in the data. PageRank Affinity is also provably related to cluster co-membership, making it a meaningful measure. In our experiments on protein networks we find that our measure is better at predicting co-complex membership and finding functionally related proteins than other commonly used measures of closeness. Moreover, our experiments indicate that PageRank Affinity is very resilient to noise in the network. In addition, based on our method we build a tool that quickly finds nodes closest to a queried protein in any protein network, and easily scales to much larger biological networks. We define a meaningful way to assess the closeness of two proteins in a PPI network, and show that our closeness measure is more biologically significant than other commonly used methods. We also develop a tool, accessible at http://xialab.bu.edu/resources/pnns, that allows the user to quickly find nodes closest to a queried vertex in any protein

  6. Spectral affinity in protein networks

    Directory of Open Access Journals (Sweden)

    Teng Shang-Hua

    2009-11-01

    Full Text Available Abstract Background Protein-protein interaction (PPI networks enable us to better understand the functional organization of the proteome. We can learn a lot about a particular protein by querying its neighborhood in a PPI network to find proteins with similar function. A spectral approach that considers random walks between nodes of interest is particularly useful in evaluating closeness in PPI networks. Spectral measures of closeness are more robust to noise in the data and are more precise than simpler methods based on edge density and shortest path length. Results We develop a novel affinity measure for pairs of proteins in PPI networks, which uses personalized PageRank, a random walk based method used in context-sensitive search on the Web. Our measure of closeness, which we call PageRank Affinity, is proportional to the number of times the smaller-degree protein is visited in a random walk that restarts at the larger-degree protein. PageRank considers paths of all lengths in a network, therefore PageRank Affinity is a precise measure that is robust to noise in the data. PageRank Affinity is also provably related to cluster co-membership, making it a meaningful measure. In our experiments on protein networks we find that our measure is better at predicting co-complex membership and finding functionally related proteins than other commonly used measures of closeness. Moreover, our experiments indicate that PageRank Affinity is very resilient to noise in the network. In addition, based on our method we build a tool that quickly finds nodes closest to a queried protein in any protein network, and easily scales to much larger biological networks. Conclusion We define a meaningful way to assess the closeness of two proteins in a PPI network, and show that our closeness measure is more biologically significant than other commonly used methods. We also develop a tool, accessible at http://xialab.bu.edu/resources/pnns, that allows the user to

  7. A Spectral Emissivity Library of Spoil Substrates

    Czech Academy of Sciences Publication Activity Database

    Pivovarník, Marek; Pikl, Miroslav; Frouz, J.; Zemek, František; Kopačková, V.; Notesco, G.; Ben Dor, E.

    2016-01-01

    Roč. 1, č. 2 (2016) E-ISSN 2306-5729 R&D Projects: GA MŠk(CZ) LO1415 Institutional support: RVO:86652079 Keywords : post- mining sites * spectral emissivity * spectral library * spoil substrates Subject RIV: EH - Ecology, Behaviour OBOR OECD: Environmental sciences (social aspects to be 5.7)

  8. Relaxation schemes for Chebyshev spectral multigrid methods

    Science.gov (United States)

    Kang, Yimin; Fulton, Scott R.

    1993-01-01

    Two relaxation schemes for Chebyshev spectral multigrid methods are presented for elliptic equations with Dirichlet boundary conditions. The first scheme is a pointwise-preconditioned Richardson relaxation scheme and the second is a line relaxation scheme. The line relaxation scheme provides an efficient and relatively simple approach for solving two-dimensional spectral equations. Numerical examples and comparisons with other methods are given.

  9. Active spectral imaging nondestructive evaluation (SINDE) camera

    Energy Technology Data Exchange (ETDEWEB)

    Simova, E.; Rochefort, P.A., E-mail: eli.simova@cnl.ca [Canadian Nuclear Laboratories, Chalk River, Ontario (Canada)

    2016-06-15

    A proof-of-concept video camera for active spectral imaging nondestructive evaluation has been demonstrated. An active multispectral imaging technique has been implemented in the visible and near infrared by using light emitting diodes with wavelengths spanning from 400 to 970 nm. This shows how the camera can be used in nondestructive evaluation to inspect surfaces and spectrally identify materials and corrosion. (author)

  10. Stellar Spectral Classification with Locality Preserving Projections ...

    Indian Academy of Sciences (India)

    With the help of computer tools and algorithms, automatic stellar spectral classification has become an area of current interest. The process of stellar spectral classification mainly includes two steps: dimension reduction and classification. As a popular dimensionality reduction technique, Principal Component Analysis (PCA) ...

  11. Basic Functional Analysis Puzzles of Spectral Flow

    DEFF Research Database (Denmark)

    Booss-Bavnbek, Bernhelm

    2011-01-01

    We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles.......We explain an array of basic functional analysis puzzles on the way to general spectral flow formulae and indicate a direction of future topological research for dealing with these puzzles....

  12. Measurement of spectral linewidths of semiconductor lasers

    Energy Technology Data Exchange (ETDEWEB)

    Du Xiaocheng; He Zhengchuan; Tang Sulan

    1987-03-01

    Based on the van der Pol equation, formulas describing the measurement of spectral linewidths of semiconductor lasers with the delayed self-heterodyne method were deduced and the influence of the spectral parameters on the measurement are given. Experimental results of single frequency semiconductor lasers are reported.

  13. Online Multi-Spectral Meat Inspection

    DEFF Research Database (Denmark)

    Nielsen, Jannik Boll; Larsen, Anders Boesen Lindbo

    2013-01-01

    We perform an explorative study on multi-spectral image data from a prototype device developed for fast online quality inspection of meat products. Because the camera setup is built for speed, we sacrifice exact pixel correspondences between the different bands of the multi-spectral images. Our...

  14. Sums of two-dimensional spectral triples

    DEFF Research Database (Denmark)

    Christensen, Erik; Ivan, Cristina

    2007-01-01

    We study countable sums of two dimensional modules for the continuous complex functions on a compact metric space and show that it is possible to construct a spectral triple which gives the original metric back. This spectral triple will be finitely summable for any positive parameter. We also co...

  15. Spectral features : How to reduce them

    NARCIS (Netherlands)

    Brug, H. van; Bloemendal, D. ten; Goeij, B. de; Vink, R.; Maresi, L.

    2009-01-01

    Spectral features are introduced by the diffuser that is used during on-board sun calibration. New findings are presented on how to reduce the size of these spectral features. Reduction can be obtained via optical design of the calibration unit, but also in creating a better diffuser. A novel

  16. Spectral Learning for Supervised Topic Models.

    Science.gov (United States)

    Ren, Yong; Wang, Yining; Zhu, Jun

    2018-03-01

    Supervised topic models simultaneously model the latent topic structure of large collections of documents and a response variable associated with each document. Existing inference methods are based on variational approximation or Monte Carlo sampling, which often suffers from the local minimum defect. Spectral methods have been applied to learn unsupervised topic models, such as latent Dirichlet allocation (LDA), with provable guarantees. This paper investigates the possibility of applying spectral methods to recover the parameters of supervised LDA (sLDA). We first present a two-stage spectral method, which recovers the parameters of LDA followed by a power update method to recover the regression model parameters. Then, we further present a single-phase spectral algorithm to jointly recover the topic distribution matrix as well as the regression weights. Our spectral algorithms are provably correct and computationally efficient. We prove a sample complexity bound for each algorithm and subsequently derive a sufficient condition for the identifiability of sLDA. Thorough experiments on synthetic and real-world datasets verify the theory and demonstrate the practical effectiveness of the spectral algorithms. In fact, our results on a large-scale review rating dataset demonstrate that our single-phase spectral algorithm alone gets comparable or even better performance than state-of-the-art methods, while previous work on spectral methods has rarely reported such promising performance.

  17. GISS GCMAM Modeled Climate Responses to Total and Spectral Solar Forcing on Decadal and Centennial Time Scales

    Science.gov (United States)

    Wen, G.; Cahalan, R. F.; Rind, D. H.; Jonas, J.; Pilewskie, P.; Harder, J. W.; Krivova, N.

    2014-12-01

    We examine the influence of the SORCE (Solar Radiation and Climate Experiment) SIM (Spectral Irradiance Monitor) observed spectral solar irradiance (SSI) variations on Earth's climate. We apply two reconstructed spectral solar forcing scenarios, one SIM based, the other based on the SATIRE (Spectral And Total Irradiance REconstruction) model, as inputs to the GISS (Goddard Institute for Space Studies) GCMAM (Global Climate Middle Atmosphere Model) to examine the climate responses on decadal and centennial time scales. We show that the atmosphere has different temperature, ozone, and dynamic responses to the two solar spectral forcing scenarios, even when the variations in TSI (Total Solar Irradiance) are the same. We find that solar variations under either scenario contribute a small fraction of the observed temperature increase since the industrial revolution. The trend of global averaged surface air temperature response to the SIM-based solar forcing is 0.02 °C/century, about half of the temperature trend to the SATIRE-based SSI. However the temporal variation of the surface air temperature for the SIM-based solar forcing scenario is much larger compared to its SATIRE counterpart. Further research is required to examine TSI and SSI variations in the ascending phase of solar cycle 24, to assess their implications for the solar influence on climate.

  18. First-principles study of SO2 sensors based on phosphorene and its isoelectronic counterparts: GeS, GeSe, SnS, SnSe

    Science.gov (United States)

    Guo, Shiying; Yuan, Lu; Liu, Xuhai; Zhou, Wenhan; Song, Xiufeng; Zhang, Shengli

    2017-10-01

    Phosphorene and its isoelectronic counterparts, such as GeS, GeSe, SnS and SnSe monolayers, show great potential in electrical and sensing applications. Here, we study the SO2 sensing properties of phosphorene and its isoelectronic counterparts by first-principles calculations. Results predict that the SO2 molecule as electron acceptor holds high adsorption strength with the five monolayer substrates, especially for SnS and SnSe monolayers. Moreover, the electronic properties of the five substrates can be modified by the SO2 molecule, together with distinct charge transfer, rendering them promising for application as a high-performance gas sensor.

  19. Definition of the Cattle Killer Cell Ig–like Receptor Gene Family: Comparison with Aurochs and Human Counterparts

    Science.gov (United States)

    Sanderson, Nicholas D.; Norman, Paul J.; Guethlein, Lisbeth A.; Ellis, Shirley A.; Williams, Christina; Breen, Matthew; Park, Steven D. E.; Magee, David A.; Babrzadeh, Farbod; Warry, Andrew; Watson, Mick; Bradley, Daniel G.; MacHugh, David E.; Parham, Peter

    2014-01-01

    Under selection pressure from pathogens, variable NK cell receptors that recognize polymorphic MHC class I evolved convergently in different species of placental mammal. Unexpectedly, diversified killer cell Ig–like receptors (KIRs) are shared by simian primates, including humans, and cattle, but not by other species. Whereas much is known of human KIR genetics and genomics, knowledge of cattle KIR is limited to nine cDNA sequences. To facilitate comparison of the cattle and human KIR gene families, we determined the genomic location, structure, and sequence of two cattle KIR haplotypes and defined KIR sequences of aurochs, the extinct wild ancestor of domestic cattle. Larger than its human counterpart, the cattle KIR locus evolved through successive duplications of a block containing ancestral KIR3DL and KIR3DX genes that existed before placental mammals. Comparison of two cattle KIR haplotypes and aurochs KIR show the KIR are polymorphic and the gene organization and content appear conserved. Of 18 genes, 8 are functional and 10 were inactivated by point mutation. Selective inactivation of KIR3DL and activating receptor genes leaves a functional cohort of one inhibitory KIR3DL, one activating KIR3DX, and six inhibitory KIR3DX. Functional KIR diversity evolved from KIR3DX in cattle and from KIR3DL in simian primates. Although independently evolved, cattle and human KIR gene families share important function-related properties, indicating that cattle KIR are NK cell receptors for cattle MHC class I. Combinations of KIR and MHC class I are the major genetic factors associated with human disease and merit investigation in cattle. PMID:25398326

  20. Paying for convenience: comparing the cost of takeaway meals with their healthier home-cooked counterparts in New Zealand.

    Science.gov (United States)

    Mackay, Sally; Vandevijvere, Stefanie; Xie, Pei; Lee, Amanda; Swinburn, Boyd

    2017-09-01

    Convenience and cost impact on people's meal decisions. Takeaway and pre-prepared foods save preparation time but may contribute to poorer-quality diets. Analysing the impact of time on relative cost differences between meals of varying convenience contributes to understanding the barrier of time to selecting healthy meals. Six popular New Zealand takeaway meals were identified from two large national surveys and compared with similar, but healthier, home-made and home-assembled meals that met nutrition targets consistent with New Zealand Eating and Activity Guidelines. The cost of each complete meal, cost per kilogram, and confidence intervals of the cost of each meal type were calculated. The time-inclusive cost was calculated by adding waiting or preparation time cost at the minimum wage. A large urban area in New Zealand. For five of six popular meals, the mean cost of the home-made and home-assembled meals was cheaper than the takeaway meals. When the cost of time was added, all home-assembled meal options were the cheapest and half of the home-made meals were at least as expensive as the takeaway meals. The home-prepared meals were designed to provide less saturated fat and Na and more vegetables than their takeaway counterparts; however, the home-assembled meals provided more Na than the home-made meals. Healthier home-made and home-assembled meals were, except one, cheaper options than takeaways. When the cost of time was added, either the home-made or the takeaway meal was the most expensive. This research questions whether takeaways are better value than home-prepared meals.

  1. Acetylcholinesterase immobilization and characterization, and comparison of the activity of the porous silicon-immobilized enzyme with its free counterpart

    Science.gov (United States)

    Saleem, Muhammad; Rafiq, Muhammad; Seo, Sung-Yum; Lee, Ki Hwan

    2016-01-01

    A successful prescription is presented for acetylcholinesterase physically adsorbed on to a mesoporous silicon surface, with a promising hydrolytic response towards acetylthiocholine iodide. The catalytic behaviour of the immobilized enzyme was assessed by spectrophotometric bioassay using neostigmine methyl sulfate as a standard acetycholinesterase inhibitor. The surface modification was studied through field emission SEM, Fourier transform IR spectroscopy, energy-dispersive X-ray spectroscopy, cathode luminescence and X-ray photoelectron spectroscopy analysis, photoluminescence measurement and spectrophotometric bioassay. The porous silicon-immobilized enzyme not only yielded greater enzyme stability, but also significantly improved the native photoluminescence at room temperature of the bare porous silicon architecture. The results indicated the promising catalytic behaviour of immobilized enzyme compared with that of its free counterpart, with a greater stability, and that it aided reusability and easy separation from the reaction mixture. The porous silicon-immobilized enzyme was found to retain 50% of its activity, promising thermal stability up to 90°C, reusability for up to three cycles, pH stability over a broad pH of 4–9 and a shelf-life of 44 days, with an optimal hydrolytic response towards acetylthiocholine iodide at variable drug concentrations. On the basis of these findings, it was believed that the porous silicon-immobilized enzyme could be exploited as a reusable biocatalyst and for screening of acetylcholinesterase inhibitors from crude plant extracts and synthesized organic compounds. Moreover, the immobilized enzyme could offer a great deal as a viable biocatalyst in bioprocessing for the chemical and pharmaceutical industries, and bioremediation to enhance productivity and robustness. PMID:26839417

  2. Meson spectral functions at finite temperature

    International Nuclear Information System (INIS)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

    2002-01-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature

  3. Meson spectral functions at finite temperature

    International Nuclear Information System (INIS)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S.

    2001-10-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T c . The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64) 3 x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

  4. Meson spectral functions at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S

    2002-03-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature.

  5. Meson spectral functions at finite temperature

    Energy Technology Data Exchange (ETDEWEB)

    Wetzorke, I.; Karsch, F.; Laermann, E.; Petreczky, P.; Stickan, S. [Bielefeld Univ. (Germany). Fakultaet fuer Physik

    2001-10-01

    The Maximum Entropy Method provides a Bayesian approach to reconstruct the spectral functions from discrete points in Euclidean time. The applicability of the approach at finite temperature is probed with the thermal meson correlation function. Furthermore the influence of fuzzing/smearing techniques on the spectral shape is investigated. We present first results for meson spectral functions at several temperatures below and above T{sub c}. The correlation functions were obtained from quenched calculations with Clover fermions on large isotropic lattices of the size (24 - 64){sup 3} x 16. We compare the resulting pole masses with the ones obtained from standard 2-exponential fits of spatial and temporal correlation functions at finite temperature and in the vacuum. The deviation of the meson spectral functions from free spectral functions is examined above the critical temperature. (orig.)

  6. Extracting attosecond delays from spectrally overlapping interferograms

    Science.gov (United States)

    Jordan, Inga; Wörner, Hans Jakob

    2018-02-01

    Attosecond interferometry is becoming an increasingly popular technique for measuring the dynamics of photoionization in real time. Whereas early measurements focused on atomic systems with very simple photoelectron spectra, the technique is now being applied to more complex systems including isolated molecules and solids. The increase in complexity translates into an augmented spectral congestion, unavoidably resulting in spectral overlap in attosecond interferograms. Here, we discuss currently used methods for phase retrieval and introduce two new approaches for determining attosecond photoemission delays from spectrally overlapping photoelectron spectra. We show that the previously used technique, consisting in the spectral integration of the areas of interest, does in general not provide reliable results. Our methods resolve this problem, thereby opening the technique of attosecond interferometry to complex systems and fully exploiting its specific advantages in terms of spectral resolution compared to attosecond streaking.

  7. Spectral analysis of bedform dynamics

    DEFF Research Database (Denmark)

    Winter, Christian; Ernstsen, Verner Brandbyge; Noormets, Riko

    Successive multibeam echo sounder surveys in tidal channels off Esbjerg (Denmark) on the North Sea coast reveal the dynamics of subaquatic compound dunes. Mainly driven by tidal currents, dune structures show complex migration patterns in all temporal and spatial scales. Common methods for the an....... The proposed method overcomes the above mentioned problems of common descriptive analysis as it is an objective and straightforward mathematical process. The spectral decomposition of superimposed dunes allows a detailed description and analysis of dune patterns and migration.......Successive multibeam echo sounder surveys in tidal channels off Esbjerg (Denmark) on the North Sea coast reveal the dynamics of subaquatic compound dunes. Mainly driven by tidal currents, dune structures show complex migration patterns in all temporal and spatial scales. Common methods...... allows the application of a procedure, which has been a standard for the analysis of water waves for long times: The bathymetric signal of a cross-section of subaquatic compound dunes is approximated by the sum of a set of harmonic functions, derived by Fourier transformation. If the wavelength...

  8. Spectral Interferometry with Electron Microscopes.

    Science.gov (United States)

    Talebi, Nahid

    2016-09-21

    Interference patterns are not only a defining characteristic of waves, but also have several applications; characterization of coherent processes and holography. Spatial holography with electron waves, has paved the way towards space-resolved characterization of magnetic domains and electrostatic potentials with angstrom spatial resolution. Another impetus in electron microscopy has been introduced by ultrafast electron microscopy which uses pulses of sub-picosecond durations for probing a laser induced excitation of the sample. However, attosecond temporal resolution has not yet been reported, merely due to the statistical distribution of arrival times of electrons at the sample, with respect to the laser time reference. This is however, the very time resolution which will be needed for performing time-frequency analysis. These difficulties are addressed here by proposing a new methodology to improve the synchronization between electron and optical excitations through introducing an efficient electron-driven photon source. We use focused transition radiation of the electron as a pump for the sample. Due to the nature of transition radiation, the process is coherent. This technique allows us to perform spectral interferometry with electron microscopes, with applications in retrieving the phase of electron-induced polarizations and reconstructing dynamics of the induced vector potential.

  9. Method of photon spectral analysis

    Science.gov (United States)

    Gehrke, Robert J.; Putnam, Marie H.; Killian, E. Wayne; Helmer, Richard G.; Kynaston, Ronnie L.; Goodwin, Scott G.; Johnson, Larry O.

    1993-01-01

    A spectroscopic method to rapidly measure the presence of plutonium in soils, filters, smears, and glass waste forms by measuring the uranium L-shell x-ray emissions associated with the decay of plutonium. In addition, the technique can simultaneously acquire spectra of samples and automatically analyze them for the amount of americium and .gamma.-ray emitting activation and fission products present. The samples are counted with a large area, thin-window, n-type germanium spectrometer which is equally efficient for the detection of low-energy x-rays (10-2000 keV), as well as high-energy .gamma. rays (>1 MeV). A 8192- or 16,384 channel analyzer is used to acquire the entire photon spectrum at one time. A dual-energy, time-tagged pulser, that is injected into the test input of the preamplifier to monitor the energy scale, and detector resolution. The L x-ray portion of each spectrum is analyzed by a linear-least-squares spectral fitting technique. The .gamma.-ray portion of each spectrum is analyzed by a standard Ge .gamma.-ray analysis program. This method can be applied to any analysis involving x- and .gamma.-ray analysis in one spectrum and is especially useful when interferences in the x-ray region can be identified from the .gamma.-ray analysis and accommodated during the x-ray analysis.

  10. Spectral partitioning in equitable graphs.

    Science.gov (United States)

    Barucca, Paolo

    2017-06-01

    Graph partitioning problems emerge in a wide variety of complex systems, ranging from biology to finance, but can be rigorously analyzed and solved only for a few graph ensembles. Here, an ensemble of equitable graphs, i.e., random graphs with a block-regular structure, is studied, for which analytical results can be obtained. In particular, the spectral density of this ensemble is computed exactly for a modular and bipartite structure. Kesten-McKay's law for random regular graphs is found analytically to apply also for modular and bipartite structures when blocks are homogeneous. An exact solution to graph partitioning for two equal-sized communities is proposed and verified numerically, and a conjecture on the absence of an efficient recovery detectability transition in equitable graphs is suggested. A final discussion summarizes results and outlines their relevance for the solution of graph partitioning problems in other graph ensembles, in particular for the study of detectability thresholds and resolution limits in stochastic block models.

  11. Spectral statistics of 'cellular' billiards

    International Nuclear Information System (INIS)

    Gutkin, Boris

    2011-01-01

    For a bounded domain Ω 0 subset of R 2 whose boundary contains a number of flat pieces Γ i , i = 1, ..., l we consider a family of non-symmetric billiards Ω constructed by patching several copies of Ω 0 along Γ i s. It is demonstrated that the length spectrum of the periodic orbits in Ω is degenerate with the multiplicities determined by a matrix group G. We study the energy spectrum of the corresponding quantum billiard problem in Ω and show that it can be split into a number of uncorrelated subspectra corresponding to a set of irreducible representations α of G. Assuming that the classical dynamics in Ω 0 are chaotic, we derive a semiclassical trace formula for each spectral component and show that their energy level statistics are the same as in standard random matrix ensembles. Depending on whether α is real, pseudo-real or complex, the spectrum has either Gaussian orthogonal, Gaussian symplectic or Gaussian unitary types of statistics, respectively

  12. Spectral characterization of Quillaja saponaria (Mol.

    Directory of Open Access Journals (Sweden)

    T. Acuña

    2016-12-01

    Full Text Available This paper presents a spectral reflectance characterization of the specie Quillaja saponaria (Mol., endemic tree of Chile and valued by society due to its provision of several ecosystem services that gives to society and also for its high concentration of saponins in cortex widely used in the pharmacological industry. For spectral characterization a foliar spectral signatures protocol was designed which included standardized instrumental and environmental parameters. The spectral response of different individuals was measured to evaluate the spectral behaviour and degree of variability within species in the visible and near infrared ranges (VNIR; 400-990 nm with two hyperspectral sensors (ASD HH and camera PDF-65-V10E. The resulting spectral signatures obtained with ASD HH showed a variation less than 5% of reflectance in VNIR and lesser than that in the transition zone from red to near infrared (red-edge; 680-730 nm. Additionally, two distinctive spectral features were detected for the specie, the first is related to a fast increase of reflectance in bands 450-480 nm and the second, to a marked decrease in the 920-970 nm range associated with water absorption features. At branch level, these distinctive features are maintained but with a smaller magnitude of reflectance, which could indicate that they are useful characteristic spectral patterns that can eventually be used for monitoring the physical health state of the specie using remote sensing. On the other hand, we used a PDF-65 camera for study the plant vigour from different health states (healthy, ill, died with spectral vegetation index. The Plant Senescence Reflectance Index detected stress on leaves, and Triangular Vegetation Index allows for a gradually characterization of every state. This work provides the first spectral reference for one of the most important sclerophyll species of Chile.

  13. X-Ray Spectral Properties of Seven Heavily Obscured Seyfert 2 Galaxies

    Energy Technology Data Exchange (ETDEWEB)

    Marchesi, S.; Ajello, M. [Department of Physics and Astronomy, Clemson University, Clemson, SC 29634 (United States); Comastri, A. [INAF—Osservatorio Astronomico di Bologna, via Ranzani 1, I-40127 Bologna (Italy); Cusumano, G.; Parola, V. La; Segreto, A., E-mail: smarche@clemson.edu [INAF—Istituto di Astrofisica Spaziale e Fisica Cosmica, Via U. La Malfa 153, I-90146 Palermo (Italy)

    2017-02-10

    We present the combined Chandra and Swift -BAT spectral analysis of seven Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog. We selected nearby ( z ≤ 0.03) sources lacking a ROSAT counterpart that never previously been observed with Chandra in the 0.3–10 keV energy range, and targeted these objects with 10 ks Chandra ACIS-S observations. The X-ray spectral fitting over the 0.3–150 keV energy range allows us to determine that all the objects are significantly obscured, with N{sub H} ≥ 10{sup 23} cm{sup −2} at a >99% confidence level. Moreover, one to three sources are candidate Compton-thick Active Galactic Nuclei (CT-AGNs; i.e., N{sub H}≥10{sup 24} cm{sup −2}). We also test the recent spectral curvature method developed by Koss et al. to find candidate CT-AGNs, finding a good agreement between our results and their predictions. Because the selection criteria we adopted were effective in detecting highly obscured AGNs, further observations of these and other Seyfert 2 galaxies selected from the Swift -BAT 100 month catalog will allow us to create a statistically significant sample of highly obscured AGNs, therefore providing a better understanding of the physics of the obscuration processes.

  14. SPECTRAL SMILE CORRECTION IN CRISM HYPERSPECTRAL IMAGES

    Science.gov (United States)

    Ceamanos, X.; Doute, S.

    2009-12-01

    The Compact Reconnaissance Imaging Spectrometer for Mars (CRISM) is affected by a common artifact in "push-broom" sensors, the so-called "spectral smile". As a consequence, both central wavelength and spectral width of the spectral response vary along the across-track dimension, thus giving rise to a shifting and smoothing of spectra (see Fig. 1 (left)). In fact, both effects are greater for spectra on the edges, while they are minimum for data acquired by central detectors, the so-called "sweet spot". The prior artifacts become particularly critical for Martian observations which contain steep spectra such as CO2 ice-rich polar images. Fig. 1 (right) shows the horizontal brightness gradient which appears in every band corresponding to a steep portion of spectra. The correction of CRISM spectral smile is addressed using a two-step method which aims at modifying data sensibly in order to mimic the optimal CRISM response. First, all spectra, which are previously interpolated by cubic splines, are resampled to the "sweet spot" wavelengths in order to overcome the spectra shift. Secondly, the non-uniform spectral width is overcome by mimicking an increase of spectral resolution thanks to a spectral sharpening. In order to minimize noise, only bands particularly suffering from smile are selected. First, bands corresponding to the outliers of the Minimum Noise Transformation (MNF) eigenvector, which corresponds to the MNF band related to smile (MNF-smile), are selected. Then, a spectral neighborhood Θi, which takes into account the local spectral convexity or concavity, is defined for every selected band in order to maximize spectral shape preservation. The proposed sharpening technique takes into account both the instrument parameters and the observed spectra. First, every reflectance value belonging to a Θi is reevaluated by a sharpening which depends on a ratio of the spectral width of the current detector and the "sweet spot" one. Then, the optimal degree of

  15. Spectrally selective solar energy materials

    International Nuclear Information System (INIS)

    Sikkens, M.

    1981-01-01

    The performance and properties of spectrally selective materials are considered and, in particular, the selective absorption of solar radiation by free electrons is discussed, both in a homogeneous material in which these electrons are strongly scattered, and in a composite material consisting of small metal particles in a dielectric host. Such materials can be used as selective absorbers if they are deposited as a thin film onto a metal substrate, the latter providing the required low emittance. This type of selective surfaces is produced by reactive sputtering of Ni in an Ar/CH 4 gas mixture. This method can yield Ni films with a considerable carbon concentration. The carbon concentration can be varied over a wide range by adjusting the partial methane pressure. The associated experimental techniques are discussed. As the carbon concentration increases, the structure of the films changes from a Ni phase in which carbon is dissolved, via an intermediate Ni 3 C phase into an amorphous carbon phase with a high electrical resistivity in which small nickel particles are embedded. Both mechanisms of selective absorption by free electrons are observed and are found to be well described by rather simple models. The best selectivity is obtained at high carbon concentrations where the films consist of nickel particles in carbon. Depending on the film thickness and the substrate material, the solar absorptance varies between 0.78 and 0.90, while the thermal emittance varies between 0.025 and 0.04. Since the films are found to be stable at 400 0 C in vacuum, it appears that these films are good candidates for application in photothermal solar energy conversion at temperature levels around 200 0 C and higher. (Auth.)

  16. Overweight and obesity among Ghanaian residents in the Netherlands: How do they weigh against their urban and rural counterparts in Ghana?

    NARCIS (Netherlands)

    Agyemang, C.; Owusu-Dabo, E.; Jonge, A. de; Martins, D.; Ogedegbe, G.; Stronks, K.

    2009-01-01

    Objective: To investigate differences in overweight and obesity between first-generation Dutch-Ghanaian migrants in The Netherlands and their rural and urban counterparts in Ghana. Design: Cross-sectional study. Subjects: A total of 1471 Ghanaians (rural Ghanaians, n 532; urban Ghanaians, n 787;

  17. Overweight and obesity among Ghanaian residents in The Netherlands: how do they weigh against their urban and rural counterparts in Ghana?

    NARCIS (Netherlands)

    Agyemang, Charles; Owusu-Dabo, Ellis; de Jonge, Ank; Martins, David; Ogedegbe, Gbenga; Stronks, Karien

    2009-01-01

    OBJECTIVE: To investigate differences in overweight and obesity between first-generation Dutch-Ghanaian migrants in The Netherlands and their rural and urban counterparts in Ghana. DESIGN: Cross-sectional study. SUBJECTS: A total of 1471 Ghanaians (rural Ghanaians, n 532; urban Ghanaians, n 787;

  18. Comparison of Scores on the WAIS and Its Puerto Rican Counterpart, Escala de Inteligencia Wechsler para Adultos, in an Institutionalized Latin American Psychiatric Population.

    Science.gov (United States)

    Davis, Todd McLin; Rodriguez, Vene L.

    1979-01-01

    Compared vocabulary and block design subtests of the Wechsler Adult Intelligence Scale (WAIS) and its Puerto Rican counterpart, the Escala de Inteligencia Wechsler para Adultos (EIWA), in hospitalized Latins and Trans-Caribbean Blacks. EIWA scores were significantly higher than WAIS scores. Equivalence of EIWA and WAIS estimates is questioned.…

  19. The cost of blocking the mirror generalization process in reading: evidence for the role of inhibitory control in discriminating letters with lateral mirror-image counterparts.

    Science.gov (United States)

    Borst, Grégoire; Ahr, Emmanuel; Roell, Margot; Houdé, Olivier

    2015-02-01

    Mirror generalization is detrimental for identifying letters with lateral mirror-image counterparts ('b/d'). In the present study, we investigated whether the discrimination of this type of letters in expert readers might be rooted in the ability to inhibit the mirror-generalization process. In our negative priming paradigm, participants judged whether two letters were identical on the prime and two animals (or buildings) were identical on the probe. In Experiment 1, participants required more time when determining that two animals (but not two buildings) were mirror images of each other when preceded by letters with mirror-image counterparts than without mirror-image counterparts ('a/h'). In Experiment 2, we replicated the results with different letters without mirror-image counterparts and with the type of probe stimuli (animal or building) manipulated as a within-subject factors. Our results suggest that expert readers never completely "unlearn" the mirror-generalization process and still need to inhibit this heuristic to overcome mirror errors.

  20. Nonlinear spectral imaging of biological tissues

    Science.gov (United States)

    Palero, J. A.

    2007-07-01

    The work presented in this thesis demonstrates live high resolution 3D imaging of tissue in its native state and environment. The nonlinear interaction between focussed femtosecond light pulses and the biological tissue results in the emission of natural autofluorescence and second-harmonic signal. Because biological intrinsic emission is generally very weak and extends from the ultraviolet to the visible spectral range, a broad-spectral range and high sensitivity 3D spectral imaging system is developed. Imaging the spectral characteristics of the biological intrinsic emission reveals the structure and biochemistry of the cells and extra-cellular components. By using different methods in visualizing the spectral images, discrimination between different tissue structures is achieved without the use of any stain or fluorescent label. For instance, RGB real color spectral images of the intrinsic emission of mouse skin tissues show blue cells, green hair follicles, and purple collagen fibers. The color signature of each tissue component is directly related to its characteristic emission spectrum. The results of this study show that skin tissue nonlinear intrinsic emission is mainly due to the autofluorescence of reduced nicotinamide adenine dinucleotide (phosphate), flavins, keratin, melanin, phospholipids, elastin and collagen and nonlinear Raman scattering and second-harmonic generation in Type I collagen. In vivo time-lapse spectral imaging is implemented to study metabolic changes in epidermal cells in tissues. Optical scattering in tissues, a key factor in determining the maximum achievable imaging depth, is also investigated in this work.

  1. Chicken embryonic stem cells and primordial germ cells display different heterochromatic histone marks than their mammalian counterparts.

    Science.gov (United States)

    Kress, Clémence; Montillet, Guillaume; Jean, Christian; Fuet, Aurélie; Pain, Bertrand

    2016-01-01

    differentiated chicken ESCs and embryonic fibroblasts, and DNMT3A was strongly expressed in ESCs, differentiated ESCs and BCs. Chicken ESCs and PGCs differ from their mammalian counterparts with respect to H3K27 methylation. High enrichment of H3K27me3 at PCH is specific to pluripotent cells in chicken. Our results demonstrate that the dynamics in chromatin constitution described during mouse development is not universal to all vertebrate species.

  2. Near-infrared diffuse interstellar bands in APOGEE telluric standard star spectra . Weak bands and comparisons with optical counterparts

    Science.gov (United States)

    Elyajouri, M.; Lallement, R.; Monreal-Ibero, A.; Capitanio, L.; Cox, N. L. J.

    2017-04-01

    Aims: Information on the existence and properties of diffuse interstellar bands (DIBs) outside the optical domain is still limited. Additional infra-red (IR) measurements and IR-optical correlative studies are needed to constrain DIB carriers and locate various absorbers in 3D maps of the interstellar matter. Methods: We extended our study of H-band DIBs in Apache Point Observatory Galactic Evolution Experiment (APOGEE) Telluric Standard Star (TSS) spectra. We used the strong λ15273 band to select the most and least absorbed targets. We used individual spectra of the former subsample to extract weaker DIBs, and we searched the two stacked series for differences that could indicate additional bands. High-resolution NARVAL and SOPHIE optical spectra for a subsample of 55 TSS targets were additionally recorded for NIR/optical correlative studies. Results: From the TSS spectra we extract a catalog of measurements of the poorly studied λλ15617, 15653, and 15673 DIBs in ≃300 sightlines, we obtain a first accurate determination of their rest wavelength and constrained their intrinsic width and shape. In addition, we studied the relationship between these weak bands and the strong λ15273 DIB. We provide a first or second confirmation of several other weak DIBs that have been proposed based on different instruments, and we add new constraints on their widths and locations. We finally propose two new DIB candidates. Conclusions: We compared the strength of the λ15273 absorptions with their optical counterparts λλ5780, 5797, 6196, 6283, and 6614. Using the 5797-5780 ratio as a tracer of shielding against the radiation field, we showed that the λ15273 DIB carrier is significantly more abundant in unshielded (σ-type) clouds, and it responds even more strongly than the λ5780 band carrier to the local ionizing field. Full Table 5 is available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc

  3. The Intestinal Mycobiota in Wild Zebrafish Comprises Mainly Dothideomycetes While Saccharomycetes Predominate in Their Laboratory-Reared Counterparts

    Directory of Open Access Journals (Sweden)

    Prabhugouda Siriyappagouder

    2018-03-01

    Full Text Available As an integral part of the resident microbial community of fish intestinal tract, the mycobiota is expected to play important roles in health and disease resistance of the host. The composition of the diverse fungal communities, which colonize the intestine, is greatly influenced by the host, their diet and geographic origin. Studies of fungal communities are rare and the majority of previous studies have relied on culture-based methods. In particular, fungal communities in fish are also poorly characterized. The aim of this study was to provide an in-depth overview of the intestinal mycobiota in a model fish species (zebrafish, Danio rerio and to determine differences in fungal composition between wild and captive specimens. We have profiled the intestinal mycobiota of wild-caught (Sharavati River, India, laboratory-reared (Bodø, Norway and wild-caught-laboratory-kept (Uttara, India zebrafish by sequencing the fungal internal transcribed spacer 2 region on the Illumina MiSeq platform. Wild fish were exposed to variable environmental factors, whereas both laboratory groups were kept in controlled conditions. There were also differences in husbandry practices at Bodø and Uttara, particularly diet. Zebrafish from Bodø were reared in the laboratory for over 10 generations, while wild-caught-laboratory-kept fish from Uttara were housed in the laboratory for only 2 months before sample collection. The intestine of zebrafish contained members of more than 15 fungal classes belonging to the phyla Ascomycota, Basidiomycota, and Zygomycota. Fungal species richness and diversity distinguished the wild-caught and laboratory-reared zebrafish communities. Wild-caught zebrafish-associated mycobiota comprised mainly Dothideomycetes in contrast to their Saccharomycetes-dominated laboratory-reared counterparts. The predominant Saccharomycetes in laboratory-reared fish belonged to the saprotrophic guild. Another characteristic feature of laboratory-reared fish

  4. ON Bipolar Cells in Macaque Retina: Type-Specific Synaptic Connectivity with Special Reference to OFF Counterparts

    Science.gov (United States)

    Tsukamoto, Yoshihiko; Omi, Naoko

    2016-01-01

    To date, 12 macaque bipolar cell types have been described. This list includes all morphology types first outlined by Polyak (1941) using the Golgi method in the primate retina and subsequently identified by other researchers using electron microscopy (EM) combined with the Golgi method, serial section transmission EM (SSTEM), and immunohistochemical imaging. We used SSTEM for the rod-dense perifoveal area of macaque retina, reconfirmed ON (cone) bipolar cells to be classified as invaginating midget bipolar (IMB), diffuse bipolar (DB)4, DB5, DB6, giant bipolar (GB), and blue bipolar (BB) types, and clarified their type-specific connectivity. DB4 cells made reciprocal synapses with a kind of ON-OFF lateral amacrine cell, similar to OFF DB2 cells. GB cells contacted rods and cones, similar to OFF DB3b cells. Retinal circuits formed by GB and DB3b cells are thought to substantiate the psychophysical finding of fast rod signals in mesopic vision. DB6 cell output synapses were directed to ON midget ganglion (MG) cells at 70% of ribbon contacts, similar to OFF DB1 cells that directed 60% of ribbon contacts to OFF MG cells. IMB cells contacted medium- or long-wavelength sensitive (M/L-) cones but not short-wavelength sensitive (S-) cones, while BB cells contacted S-cones but not M/L-cones. However, IMB and BB dendrites had similar morphological architectures, and a BB cell contacting a single S-cone resembled an IMB cell. Thus, both IMB and BB may be the ON bipolar counterparts of the OFF flat midget bipolar (FMB) type, likewise DB4 of DB2, DB5 of DB3a, DB6 of DB1, and GB of DB3b OFF bipolar type. The ON DB plus GB, and OFF DB cells predominantly contacted M/L-cones and their outputs were directed mainly to parasol ganglion (PG) cells but also moderately to MG cells. BB cells directed S-cone-driven outputs almost exclusively to small bistratified ganglion (SBG) cells. Some FMB cells predominantly contacted S-cones and their outputs were directed to OFF MG cells. Thus, two

  5. NEAR-INFRARED COUNTERPARTS TO CHANDRA X-RAY SOURCES TOWARD THE GALACTIC CENTER. I. STATISTICS AND A CATALOG OF CANDIDATES

    International Nuclear Information System (INIS)

    Mauerhan, J. C.; Muno, M. P.; Morris, M. R.; Bauer, F. E.; Nishiyama, S.; Nagata, T.

    2009-01-01

    We present a catalog of 5184 candidate infrared counterparts to X-ray sources detected toward the Galactic center. The X-ray sample contains 9017 point sources detected in this region by the Chandra X-ray Observatory during the past decade, including data from a recent deep survey of the central 2 0 x 0. 0 8 of the Galactic plane. A total of 6760 of these sources have hard X-ray colors, and the majority of them lie near the Galactic center, while most of the remaining 2257 soft X-ray sources lie in the foreground. We cross-correlated the X-ray source positions with the 2MASS and SIRIUS near-infrared catalogs, which collectively contain stars with a 10σ limiting flux of K s ≤ 15.6 mag. In order to distinguish absorbed infrared sources near the Galactic center from those in the foreground, we defined red and blue sources as those which have H - K s ≥ 0.9 and <0.9 mag, respectively. We find that 5.8% ± 1.5% (2σ) of the hard X-ray sources have real infrared counterparts, of which 228 ± 99 are red and 166 ± 27 are blue. The red counterparts are probably comprised of Wolf-Rayet and O stars, high-mass X-ray binaries, and symbiotic binaries located near the Galactic center. Foreground X-ray binaries suffering intrinsic X-ray absorption could be included in the sample of blue infrared counterparts to hard X-ray sources. We also find that 39.4% ± 1.0% of the soft X-ray sources have blue infrared counterparts; most of these are probably coronally active dwarfs in the foreground. There is a noteworthy collection of ∼20 red counterparts to hard X-ray sources near the Sagittarius B H II region, which are probably massive binaries that have formed within the last several Myr. For each of the infrared matches to X-ray sources in our catalog we derived the probability that the association is real, based on the source properties and the results of the cross-correlation analysis. These data are included in our catalog and will serve spectroscopic surveys to identify

  6. Spectral modeling of magnetohydrodynamic turbulent flows.

    Science.gov (United States)

    Baerenzung, J; Politano, H; Ponty, Y; Pouquet, A

    2008-08-01

    We present a dynamical spectral model for large-eddy simulation of the incompressible magnetohydrodynamic (MHD) equations based on the eddy damped quasinormal Markovian approximation. This model extends classical spectral large-eddy simulations for the Navier-Stokes equations to incorporate general (non-Kolmogorovian) spectra as well as eddy noise. We derive the model for MHD flows and show that the introduction of an eddy damping time for the dynamics of spectral tensors, in the absence of equipartition between the velocity and magnetic fields, leads to better agreement with direct numerical simulations, an important point for dynamo computations.

  7. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VIII. A Comparison to Cosmological Short-duration Gamma-Ray Bursts

    Science.gov (United States)

    Fong, W.; Berger, E.; Blanchard, P. K.; Margutti, R.; Cowperthwaite, P. S.; Chornock, R.; Alexander, K. D.; Metzger, B. D.; Villar, V. A.; Nicholl, M.; Eftekhari, T.; Williams, P. K. G.; Annis, J.; Brout, D.; Brown, D. A.; Chen, H.-Y.; Doctor, Z.; Diehl, H. T.; Holz, D. E.; Rest, A.; Sako, M.; Soares-Santos, M.

    2017-10-01

    We present a comprehensive comparison of the properties of the radio through X-ray counterpart of GW170817 and the properties of short-duration gamma-ray bursts (GRBs). For this effort, we utilize a sample of 36 short GRBs spanning a redshift range of z≈ 0.12{--}2.6 discovered over 2004-2017. We find that the counterpart to GW170817 has an isotropic-equivalent luminosity that is ≈ 3000 times less than the median value of on-axis short GRB X-ray afterglows, and ≳104 times less than that for detected short GRB radio afterglows. Moreover, the allowed jet energies and particle densities inferred from the radio and X-ray counterparts to GW170817 and on-axis short GRB afterglows are remarkably similar, suggesting that viewing angle effects are the dominant, and perhaps only, difference in their observed radio and X-ray behavior. From comparison to previous claimed kilonovae following short GRBs, we find that the optical and near-infrared (NIR) counterpart to GW170817 is comparatively under-luminous by a factor of ≈ 3{--}5, indicating a range of kilonova luminosities and timescales. A comparison of the optical limits following short GRBs on ≲ 1 day timescales also rules out a “blue” kilonova of comparable optical isotropic-equivalent luminosity in one previous short GRB. Finally, we investigate the host galaxy of GW170817, NGC 4993, in the context of short GRB host galaxy stellar population properties. We find that NGC 4993 is superlative in terms of its large luminosity, old stellar population age, and low star formation rate compared to previous short GRB hosts. Additional events within the Advanced Laser Interferometer Gravitational-wave Observatory (LIGO)/Virgo volume will be crucial in delineating the properties of the host galaxies of neutron star-neutron star (NS-NS) mergers, and connecting them to their cosmological counterparts.

  8. Finding counterparts for all-sky X-ray surveys with NWAY: a Bayesian algorithm for cross-matching multiple catalogues

    Science.gov (United States)

    Salvato, M.; Buchner, J.; Budavári, T.; Dwelly, T.; Merloni, A.; Brusa, M.; Rau, A.; Fotopoulou, S.; Nandra, K.

    2018-02-01

    We release the AllWISE counterparts and Gaia matches to 106 573 and 17 665 X-ray sources detected in the ROSAT 2RXS and XMMSL2 surveys with |b| > 15°. These are the brightest X-ray sources in the sky, but their position uncertainties and the sparse multi-wavelength coverage until now rendered the identification of their counterparts a demanding task with uncertain results. New all-sky multi-wavelength surveys of sufficient depth, like AllWISE and Gaia, and a new Bayesian statistics based algorithm, NWAY, allow us, for the first time, to provide reliable counterpart associations. NWAY extends previous distance and sky density based association methods and, using one or more priors (e.g. colours, magnitudes), weights the probability that sources from two or more catalogues are simultaneously associated on the basis of their observable characteristics. Here, counterparts have been determined using a Wide-field Infrared Survey Explorer (WISE) colour-magnitude prior. A reference sample of 4524 XMM/Chandra and Swift X-ray sources demonstrates a reliability of ∼94.7 per cent (2RXS) and 97.4 per cent (XMMSL2). Combining our results with Chandra-COSMOS data, we propose a new separation between stars and AGN in the X-ray/WISE flux-magnitude plane, valid over six orders of magnitude. We also release the NWAY code and its user manual. NWAY was extensively tested with XMM-COSMOS data. Using two different sets of priors, we find an agreement of 96 per cent and 99 per cent with published Likelihood Ratio methods. Our results were achieved faster and without any follow-up visual inspection. With the advent of deep and wide area surveys in X-rays (e.g. SRG/eROSITA, Athena/WFI) and radio (ASKAP/EMU, LOFAR, APERTIF, etc.) NWAY will provide a powerful and reliable counterpart identification tool.

  9. Infrared spectra of protonated coronene and its neutral counterpart in solid parahydrogen: implications for unidentified interstellar infrared emission bands.

    Science.gov (United States)

    Bahou, Mohammed; Wu, Yu-Jong; Lee, Yuan-Pern

    2014-01-20

    Large protonated polycyclic aromatic hydrocarbons (H(+) PAHs) are possible carriers of unidentified infrared (UIR) emission bands from interstellar objects, but the characterization of infrared (IR) spectra of large H(+) PAHs in the laboratory is challenging. IR absorption spectra of protonated coronene (1-C24 H13 (+) ) and mono-hydrogenated coronene (1-C24 H13 (.) ), which were produced upon electron bombardment of parahydrogen containing a small proportion of coronene (C24 H12 ) during matrix deposition, were recorded. The spectra are of a much higher resolution than those obtained by IR multiphoton dissociation by Dopfer and co-workers. The IR spectra of protonated pyrene and coronene collectively appear to have the required chromophores for features of the UIR bands, and the spectral shifts on an increase in the number of benzenoid rings point in the correct direction towards the positions of the UIR bands. Larger protonated peri-condensed PAHs might thus be key species among the carriers of UIR bands. Copyright © 2014 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  10. Multi-Configuration Matched Spectral Filter Core Project

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes an open-architecture spectral gas sensor based on compressive sensing concepts employed for both spatial and spectral domains. Our matched spectral...

  11. Multi-Configuration Matched Spectral Filter Core, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes an open-architecture spectral gas sensor based on compressive sensing concepts employed for both spatial and spectral domains. Our matched spectral...

  12. Spectral Shifting in Nondestructive Assay Instrumentation

    Energy Technology Data Exchange (ETDEWEB)

    Trellue, Holly Renee [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Nettleton, Anthony Steven [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tutt, James Robert [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Menlove, Howard Olsen [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); LaFleur, Adrienne Marie [Los Alamos National Lab. (LANL), Los Alamos, NM (United States); Tobin, Stephen Joseph [Los Alamos National Lab. (LANL), Los Alamos, NM (United States)

    2016-11-17

    This project involves spectrum tailoring research that endeavors to better distinguish energies of gamma rays using different spectral material thicknesses and determine neutron energies by coating detectors with various materials.

  13. [Hygiene and the spectral energtic light pattern].

    Science.gov (United States)

    Kaptsov, V A; Deynego, V N; SoshMn, N P; Ulasyuk, V N

    There are considered methodological bases of multicriteria synthesis of a spectral energetic pattern for the evaluation of the excessive share of blue and red light in the spectrum of artificial energy sources. The basis of this methodology is relied upon on the hygienic approach to the spectrum analysis of solar and led light. Relying upon on "photobiological paradox of vision" according to M. A. Ostrovsky, conditions of "melanopsin cross" and mechanisms of adverse impact of light on vision, all the spectral-energy characteristics of solar light were divided into subspaces. The border between them became a spectral energy pattern for the evaluation of artificial sources on the security of their impact on eye and human health according to criteria of the excessive dose of blue or red light. On two examples there was shown the effectiveness and clarity of this estimation with the using of the spectral energetic pattern of light.

  14. Spectral properties of supersymmetric shape invariant potentials

    Indian Academy of Sciences (India)

    SIPs). Although the folded spectrum is completely random, unfolded spectrum shows that energy levels are highly correlated and absolutely rigid. All the SIPs exhibit harmonic oscillator-type spectral statistics in the unfolded spectrum.

  15. Salinity and spectral reflectance of soils

    Science.gov (United States)

    Szilagyi, A.; Baumgardner, M. F.

    1991-01-01

    The basic spectral response related to the salt content of soils in the visible and reflective IR wavelengths is analyzed in order to explore remote sensing applications for monitoring processes of the earth system. The bidirectional reflectance factor (BRF) was determined at 10 nm of increments over the 520-2320-nm spectral range. The effect of salts on reflectance was analyzed on the basis of 162 spectral measurements. MSS and TM bands were simulated within the measured spectral region. A strong relationship was found in variations of reflectance and soil characteristics pertaining to salinization and desalinization. Although the individual MSS bands had high R-squared values and 75-79 percent of soil/treatment combinations were separable, there was a large number of soil/treatment combinations not distinguished by any of the four highly correlated MSS bands under consideration.

  16. SSBUV middle ultraviolet solar spectral irradiance measurements

    Science.gov (United States)

    Cebula, Richard P.; Hilsenrath, Ernest

    1994-01-01

    The Shuttle Solar Backscatter Ultraviolet (SSBUV) instrument performs multiple solar spectral irradiance measurements in the wavelength region 200 to 400 nm at 1.1 nm resolution during yearly Space Shuttle flights. Solar spectral irradiance observations from the first three SSBUV Shuttle flights, October 1989, October 1990, and August 1991, are compared with one another and with solar measurements made by the NOAA-11 SBUV/2 instrument. The repeated SSBUV solar spectral observations, which agree to within plus or minus 1-2 percent from 200 to 400 nm, are valuable not only as a means of validating and calibrating the satellite-based solar irradiance measurements, but also as a distinct set of stand-alone solar measurements for monitoring long-term changes in the solar spectral irradiance, which are important for ozone photochemistry.

  17. Broadband Advanced Spectral System, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — NovaSol proposes to develop an advanced hyperspectral imaging system for earth science missions named BRASS (Broadband Advanced Spectral System). BRASS combines...

  18. Algorithms for Spectral Decomposition with Applications

    Data.gov (United States)

    National Aeronautics and Space Administration — The analysis of spectral signals for features that represent physical phenomenon is ubiquitous in the science and engineering communities. There are two main...

  19. Ultra-High Density Spectral Storage Materials

    National Research Council Canada - National Science Library

    Hasan, Zameer U

    2002-01-01

    .... Being atomic scale storage, spectral storage has the potential of providing orders of magnitude denser memories than present day memories that depend on the hulk properties of the storage medium...

  20. Chromosome analysis using spectral karyotyping (SKY).

    Science.gov (United States)

    Imataka, George; Arisaka, Osamu

    2012-01-01

    Spectral karyotyping is a novel technique for chromosome analysis that has been developed based on the approach of the fluorescence in situ hybridization technique. Spectral karyotyping makes it feasible to diagnose a variety of diseases, because of its technology in painting each of the 24 human chromosomes with different colors. In recent years, it has become possible to adopt the usage of spectral karyotyping for research in general clinical practice, and its usability has attracted particular attention in the diagnosis of different diseases. In this review, we will explain the principle of the spectral karyotyping, as well as its specificity and limitation in detecting the genetic defects within clinical application by presenting two case reports.

  1. Computer-assisted spectral design and synthesis

    Science.gov (United States)

    Vadakkumpadan, Fijoy; Wang, Qiqi; Sun, Yinlong

    2005-01-01

    In this paper, we propose a computer-assisted approach for spectral design and synthesis. This approach starts with some initial spectrum, modifies it interactively, evaluates the change, and decides the optimal spectrum. Given a requested change as function of wavelength, we model the change function using a Gaussian function. When there is the metameric constraint, from the Gaussian function of request change, we propose a method to generate the change function such that the result spectrum has the same color as the initial spectrum. We have tested the proposed method with different initial spectra and change functions, and implemented an interactive graphics environment for spectral design and synthesis. The proposed approach and graphics implementation for spectral design and synthesis can be helpful for a number of applications such as lighting of building interiors, textile coloration, and pigment development of automobile paints, and spectral computer graphics.

  2. Spectral properties of almost-periodic Hamiltonians

    International Nuclear Information System (INIS)

    Lima, R.

    1983-12-01

    We give a description of some spectral properties of almost-periodic hamiltonians. We put the stress on some particular points of the proofs of the existence of absolutely continuous or pure point spectrum [fr

  3. HIRES NIMS IDA SPECTRAL IMAGE CUBES

    Data.gov (United States)

    National Aeronautics and Space Administration — This data volume contains 17 channel spectral image cubes of asteroid 243 Ida ranging from 0.7 to 5.2 micrometers in wavelength in cgs units of radiance. These data...

  4. GALILEO NIMS SPECTRAL IMAGE CUBES: JUPITER OPERATIONS

    Data.gov (United States)

    National Aeronautics and Space Administration — The natural form of imaging spectrometer data is the spectral image cube. It is normally in band sequential format, but has a dual nature. It is a series of 'images'...

  5. GALILEO NIMS SPECTRAL IMAGE TUBES: JUPITER OPERATIONS

    Data.gov (United States)

    National Aeronautics and Space Administration — The natural form of imaging spectrometer data is the spectral image cube. It is normally in band sequential format, but has a dual nature. It is a series of 'images'...

  6. Learning theory of distributed spectral algorithms

    Science.gov (United States)

    Guo, Zheng-Chu; Lin, Shao-Bo; Zhou, Ding-Xuan

    2017-07-01

    Spectral algorithms have been widely used and studied in learning theory and inverse problems. This paper is concerned with distributed spectral algorithms, for handling big data, based on a divide-and-conquer approach. We present a learning theory for these distributed kernel-based learning algorithms in a regression framework including nice error bounds and optimal minimax learning rates achieved by means of a novel integral operator approach and a second order decomposition of inverse operators. Our quantitative estimates are given in terms of regularity of the regression function, effective dimension of the reproducing kernel Hilbert space, and qualification of the filter function of the spectral algorithm. They do not need any eigenfunction or noise conditions and are better than the existing results even for the classical family of spectral algorithms.

  7. Matched Spectral Filter Imager, Phase I

    Data.gov (United States)

    National Aeronautics and Space Administration — OPTRA proposes the development of an imaging spectrometer for greenhouse gas and volcanic gas imaging based on matched spectral filtering and compressive imaging....

  8. Precise Multi-Spectral Dermatological Imaging

    DEFF Research Database (Denmark)

    Gomez, David Delgado; Carstensen, Jens Michael; Ersbøll, Bjarne Kjær

    2004-01-01

    In this work, an integrated imaging system to obtain accurate and reproducible multi-spectral dermatological images is proposed. The system is made up of an integrating sphere, light emitting diodes and a generic monochromatic camera. The system can collect up to 10 different spectral bands....... These spectral bands vary from ultraviolet to near infrared. The welldefined and diffuse illumination of the optically closed scene aims to avoid shadows and specular reflections. Furthermore, the system has been developed to guarantee the reproducibility of the collected images. This allows for comparative...... studies of time series of images. Two experiments are conducted to show the ability of the system to acquire highly precise and standardized multi-spectral images. The first experiment aims to show the capacity of the system to collect reproducible images. The second experiment demonstrates that the multi...

  9. Learning theory of distributed spectral algorithms

    International Nuclear Information System (INIS)

    Guo, Zheng-Chu; Lin, Shao-Bo; Zhou, Ding-Xuan

    2017-01-01

    Spectral algorithms have been widely used and studied in learning theory and inverse problems. This paper is concerned with distributed spectral algorithms, for handling big data, based on a divide-and-conquer approach. We present a learning theory for these distributed kernel-based learning algorithms in a regression framework including nice error bounds and optimal minimax learning rates achieved by means of a novel integral operator approach and a second order decomposition of inverse operators. Our quantitative estimates are given in terms of regularity of the regression function, effective dimension of the reproducing kernel Hilbert space, and qualification of the filter function of the spectral algorithm. They do not need any eigenfunction or noise conditions and are better than the existing results even for the classical family of spectral algorithms. (paper)

  10. Spectral properties of 441 radio pulsars

    Science.gov (United States)

    Jankowski, F.; van Straten, W.; Keane, E. F.; Bailes, M.; Barr, E. D.; Johnston, S.; Kerr, M.

    2018-02-01

    We present a study of the spectral properties of 441 pulsars observed with the Parkes radio telescope near the centre frequencies of 728, 1382 and 3100 MHz. The observations at 728 and 3100 MHz were conducted simultaneously using the dual-band 10-50 cm receiver. These high-sensitivity, multifrequency observations provide a systematic and uniform sample of pulsar flux densities. We combine our measurements with spectral data from the literature in order to derive the spectral properties of these pulsars. Using techniques from robust regression and information theory, we classify the observed spectra in an objective, robust and unbiased way into five morphological classes: simple or broken power law, power law with either low- or high-frequency cut-off and log-parabolic spectrum. While about 79 per cent of the pulsars that could be classified have simple power-law spectra, we find significant deviations in 73 pulsars, 35 of which have curved spectra, 25 with a spectral break and 10 with a low-frequency turn-over. We identify 11 gigahertz-peaked spectrum (GPS) pulsars, with 3 newly identified in this work and 8 confirmations of known GPS pulsars; 3 others show tentative evidence of GPS, but require further low-frequency measurements to support this classification. The weighted mean spectral index of all pulsars with simple power-law spectra is -1.60 ± 0.03. The observed spectral indices are well described by a shifted log-normal distribution. The strongest correlations of spectral index are with spin-down luminosity, magnetic field at the light-cylinder and spin-down rate. We also investigate the physical origin of the observed spectral features and determine emission altitudes for three pulsars.

  11. Spectral Feature Selection for Data Mining

    CERN Document Server

    Zhao, Zheng Alan

    2011-01-01

    Spectral Feature Selection for Data Mining introduces a novel feature selection technique that establishes a general platform for studying existing feature selection algorithms and developing new algorithms for emerging problems in real-world applications. This technique represents a unified framework for supervised, unsupervised, and semisupervised feature selection. The book explores the latest research achievements, sheds light on new research directions, and stimulates readers to make the next creative breakthroughs. It presents the intrinsic ideas behind spectral feature selection, its th

  12. Measuring Collimator Infrared (IR) Spectral Transmission

    Science.gov (United States)

    2016-05-01

    TECHNICAL REPORT RDMR-WD-16-15 MEASURING COLLIMATOR INFRARED ( IR ) SPECTRAL TRANSMISSION Christopher L. Dobbins Weapons...AND DATES COVERED Final 4. TITLE AND SUBTITLE Measuring Collimator Infrared ( IR ) Spectral Transmission 5. FUNDING NUMBERS 6. AUTHOR(S) Christopher L...release; distribution is unlimited. 12b. DISTRIBUTION CODE A 13. ABSTRACT (Maximum 200 Words) Several Infrared ( IR ) imaging systems have been measured

  13. Biomimetic joint spatial-spectral pattern recognition

    Science.gov (United States)

    Caulfield, H. John

    2003-08-01

    Most animals use color and shape to recognize things in their worlds. Shapes are properties of objects inferable from their 2D images. Colors are spectral discriminants computed by their brains using data sensed in 2-4 broad, spectrally overlapping bands. So color is not an object property. Both shape and color combine to make discrimination work well. I will describe Artificial Color and then ways to recognize an Artificially colored image.

  14. A high throughput spectral image microscopy system

    Science.gov (United States)

    Gesley, M.; Puri, R.

    2018-01-01

    A high throughput spectral image microscopy system is configured for rapid detection of rare cells in large populations. To overcome flow cytometry rates and use of fluorophore tags, a system architecture integrates sample mechanical handling, signal processors, and optics in a non-confocal version of light absorption and scattering spectroscopic microscopy. Spectral images with native contrast do not require the use of exogeneous stain to render cells with submicron resolution. Structure may be characterized without restriction to cell clusters of differentiation.

  15. Spectral evolution of galaxies: current views

    International Nuclear Information System (INIS)

    Bruzual, A.G.

    1985-01-01

    A summary of current views on the interpretation of the various evolutionary tests aimed at detecting spectral evolution in galaxies is presented. It is concluded that the evolution taking place in known galaxy samples is a slow process (perhaps consistent with no evolution at all), and that the early phases of rapid spectral evolution in early-type galaxies have not yet been detected. (author)

  16. Mechanism elucidation of the cis-trans isomerization of an azole ruthenium-nitrosyl complex and its osmium counterpart.

    Science.gov (United States)

    Gavriluta, Anatolie; Büchel, Gabriel E; Freitag, Leon; Novitchi, Ghenadie; Tommasino, Jean Bernard; Jeanneau, Erwann; Kuhn, Paul-Steffen; González, Leticia; Arion, Vladimir B; Luneau, Dominique

    2013-06-03

    mechanisms have been considered. The value for the activation energy found for the dissociative mechanism is in good agreement with experimental activation enthalpy. Electrochemical investigation provides further evidence for higher reactivity of ruthenium complexes compared to that of osmium counterparts and shows that intramolecular electron transfer reactions do not affect the isomerization process. A dissociative mechanism of cis↔trans isomerization has been proposed for both ruthenium and osmium complexes.

  17. Mechanism Elucidation of the cis–trans Isomerization of an Azole Ruthenium–Nitrosyl Complex and Its Osmium Counterpart

    Science.gov (United States)

    2013-01-01

    been considered. The value for the activation energy found for the dissociative mechanism is in good agreement with experimental activation enthalpy. Electrochemical investigation provides further evidence for higher reactivity of ruthenium complexes compared to that of osmium counterparts and shows that intramolecular electron transfer reactions do not affect the isomerization process. A dissociative mechanism of cis↔trans isomerization has been proposed for both ruthenium and osmium complexes. PMID:23675748

  18. The Effect of Field Spectral Reflectance Measurement Distance to the Spectral Reflectance of Rhizophora stylosa

    Science.gov (United States)

    Kamal, M.; Ningam, M. U. L.; Alqorina, F.

    2017-12-01

    Mapping mangrove species from remote sensing data through its spectral reflectance pattern collected in the field is challenging. There are high variations in light condition, leaf orientation, canopy structure, background objects and measurement distance when measuring mangrove spectral reflectance in the field. Spectral measurement distance to the object is one of the most important aspects controlling the result of spectral reflectance pattern. This research is aimed to assess the effect of spectral reflectance pattern of Rhizophora stylosa collected at various distances. Specific objectives of this research are to collect samples of mangrove spectral reflectance pattern in the field, to assess the effect of the observation scale to the result of the spectral reflectance pattern, and to characterize the mangrove spectral reflectance pattern resulted from different observation scales. Spectral reflectance data collection in the field was conducted using JAZ EL-350 field spectrometer at 2cm, 50cm, 1m, 2m, and 5m distance and was conducted in Karimunjawa Island, Jepara, Central Java, Indonesia. A visual comparison of the spectral reflectance curve was conducted to understand the effect of measurement distance. The results of this study indicate that the difference in the measurement distance of Rhizophora stylosa species was highly influential to the resulting spectral reflectance curve. The spectral reflectance curve recorded at close range to the leaf (i.e. 2 cm) has the lowest curve variation, as well as the furthest distance (i.e. 5 m). This study is a basic study that supports the development of the use of remote sensing imagery for mangrove species mapping.

  19. A radio spectral index map and catalogue at 147-1400 MHz covering 80 per cent of the sky

    Science.gov (United States)

    de Gasperin, F.; Intema, H. T.; Frail, D. A.

    2018-03-01

    The radio spectral index is a powerful probe for classifying cosmic radio sources and understanding the origin of the radio emission. Combining data at 147 MHz and 1.4 GHz from the TIFR GMRT Sky Survey (TGSS) and the NRAO VLA Sky Survey (NVSS), we produced a large-area radio spectral index map of ˜80 per cent of the sky (Dec. > - 40 deg), as well as a radio spectral index catalogue containing 1396 515 sources, of which 503 647 are not upper or lower limits. Almost every TGSS source has a detected counterpart, while this is true only for 36 per cent of NVSS sources. We released both the map and the catalogue to the astronomical community. The catalogue is analysed to discover systematic behaviours in the cosmic radio population. We find a differential spectral behaviour between faint and bright sources as well as between compact and extended sources. These trends are explained in terms of radio galaxy evolution. We also confirm earlier reports of an excess of steep-spectrum sources along the galactic plane. This corresponds to 86 compact and steep-spectrum source in excess compared to expectations. The properties of this excess are consistent with normal non-recycled pulsars, which may have been missed by pulsation searches due to larger than average scattering along the line of sight.

  20. USGS Digital Spectral Library splib06a

    Science.gov (United States)

    Clark, Roger N.; Swayze, Gregg A.; Wise, Richard A.; Livo, K. Eric; Hoefen, Todd M.; Kokaly, Raymond F.; Sutley, Stephen J.

    2007-01-01

    Introduction We have assembled a digital reflectance spectral library that covers the wavelength range from the ultraviolet to far infrared along with sample documentation. The library includes samples of minerals, rocks, soils, physically constructed as well as mathematically computed mixtures, plants, vegetation communities, microorganisms, and man-made materials. The samples and spectra collected were assembled for the purpose of using spectral features for the remote detection of these and similar materials. Analysis of spectroscopic data from laboratory, aircraft, and spacecraft instrumentation requires a knowledge base. The spectral library discussed here forms a knowledge base for the spectroscopy of minerals and related materials of importance to a variety of research programs being conducted at the U.S. Geological Survey. Much of this library grew out of the need for spectra to support imaging spectroscopy studies of the Earth and planets. Imaging spectrometers, such as the National Aeronautics and Space Administration (NASA) Airborne Visible/Infra Red Imaging Spectrometer (AVIRIS) or the NASA Cassini Visual and Infrared Mapping Spectrometer (VIMS) which is currently orbiting Saturn, have narrow bandwidths in many contiguous spectral channels that permit accurate definition of absorption features in spectra from a variety of materials. Identification of materials from such data requires a comprehensive spectral library of minerals, vegetation, man-made materials, and other subjects in the scene. Our research involves the use of the spectral library to identify the components in a spectrum of an unknown. Therefore, the quality of the library must be very good. However, the quality required in a spectral library to successfully perform an investigation depends on the scientific questions to be answered and the type of algorithms to be used. For example, to map a mineral using imaging spectroscopy and the mapping algorithm of Clark and others (1990a, 2003b

  1. Solar spectral irradiance changes during cycle 24

    Energy Technology Data Exchange (ETDEWEB)

    Marchenko, S. V.; DeLand, M. T. [Also at NASA/Goddard Space Flight Center, Greenbelt, MD, USA. (United States)

    2014-07-10

    We use solar spectra obtained by the Ozone Monitoring Instrument (OMI) on board the Aura satellite to detect and follow long-term (years) and short-term (weeks) changes in the solar spectral irradiance (SSI) in the 265-500 nm spectral range. During solar Cycle 24, in the relatively line-free regions the SSI changed by ∼0.6% ± 0.2% around 265 nm. These changes gradually diminish to 0.15% ± 0.20% at 500 nm. All strong spectral lines and blends, with the notable exception of the upper Balmer lines, vary in unison with the solar 'continuum'. Besides the lines with strong chromospheric components, the most involved species include Fe I blends and all prominent CH, NH, and CN spectral bands. Following the general trend seen in the solar 'continuum', the variability of spectral lines also decreases toward longer wavelengths. The long-term solar cycle SSI changes are closely, to within the quoted 0.1%-0.2% uncertainties, matched by the appropriately adjusted short-term SSI variations derived from the 27 day rotational modulation cycles. This further strengthens and broadens the prevailing notion about the general scalability of the UV SSI variability to the emissivity changes in the Mg II 280 nm doublet on timescales from weeks to years. We also detect subtle deviations from this general rule: the prominent spectral lines and blends at λ ≳ 350 nm show slightly more pronounced 27 day SSI changes when compared to the long-term (years) trends. We merge the solar data from Cycle 21 with the current Cycle 24 OMI and GOME-2 observations and provide normalized SSI variations for the 170-795 nm spectral region.

  2. a Variable Resolution Global Spectral Model.

    Science.gov (United States)

    Hardiker, Vivek Manohar

    A conformal transformation suggested by F. Schimdt is followed to implement a global spectral model with variable horizontal resolution. A conformal mapping is defined between the real physical sphere (Earth) to a transformed (Computational) sphere. The model equations are discretized on the computational sphere and the conventional spectral technique is applied to solve the model equations. There are two types of transformations used in the present study, namely, the Stretching transformation and the Rotation of the horizontal grid points. Application of the stretching transformation results in finer resolution along the meridional direction. The stretching is controlled by a parameter C. The rotation transformation can be used to relocate the North Pole of the model to any point on the geographic sphere. The idea is now to rotate the pole to the area of interest and refine the resolution around the new pole by applying the stretching transformation. The stretching transformation can be applied alone without the rotation. A T-42 Spectral Shallow-Water model is transformed by applying the stretching transformation alone as well as the two transformations together. A T-42 conventional Spectral Shallow-Water model is run as the control experiment and a conventional T-85 Spectral Shallow-Water model run is treated as the benchmark (Truth) solution. RMS error analysis for the geopotential field as well as the wind field is performed to evaluate the forecast made by the transformed model. It is observed that the RMS error of the transformed model is lower than that of the control run in a latitude band, for the case of stretching transformation alone, while for the total transformation (rotation followed by stretching), similar results are obtained for a rectangular domain. A multi-level global spectral model is designed from the current FSU global spectral model in order to implement the conformal transformation. The transformed T-85 model is used to study Hurricane

  3. Schrodinger Eigenmaps for spectral target detection

    Science.gov (United States)

    Dorado-Munoz, Leidy P.; Messinger, David W.

    2015-05-01

    Spectral imagery such as multispectral and hyperspectral data could be seen as a set of panchromatic images stacked as a 3d cube, with two spatial dimensions and one spectral. For hyperspectral imagery, the spectral dimension is highly sampled, which implies redundant information and a high spectral dimensionality. Therefore, it is necessary to use transformations on the data not only to reduce processing costs, but also to reveal some features or characteristics of the data that were hidden in the original space. Schrodinger Eigenmaps (SE) is a novel mathematical method for non-linear representation of a data set that attempts to preserve the local structure while the spectral dimension is reduced. SE could be seen as an extension of Laplacian Eigenmaps (LE), where the diffusion process could be steered in certain directions determined by a potential term. SE was initially introduced as a semi supervised classification technique and most recently, it has been applied to target detection showing promising performance. In target detection, only the barrier potential has been used, so different forms to define barrier potentials and its influence on the data embedding are studied here. In this way, an experiment to assess the target detection vs. how strong the influence of potentials is and how many eigenmaps are used in the detection, is proposed. The target detection is performed using a hyperspectral data set, where several targets with different complexity are presented in the same scene.

  4. Efficient uncertainty minimization for fuzzy spectral clustering.

    Science.gov (United States)

    White, Brian S; Shalloway, David

    2009-11-01

    Spectral clustering uses the global information embedded in eigenvectors of an inter-item similarity matrix to correctly identify clusters of irregular shape, an ability lacking in commonly used approaches such as k -means and agglomerative clustering. However, traditional spectral clustering partitions items into hard clusters, and the ability to instead generate fuzzy item assignments would be advantageous for the growing class of domains in which cluster overlap and uncertainty are important. Korenblum and Shalloway [Phys. Rev. E 67, 056704 (2003)] extended spectral clustering to fuzzy clustering by introducing the principle of uncertainty minimization. However, this posed a challenging nonconvex global optimization problem that they solved by a brute-force technique unlikely to scale to data sets having more than O(10;{2}) items. Here we develop a method for solving the minimization problem, which can handle data sets at least two orders of magnitude larger. In doing so, we elucidate the underlying structure of uncertainty minimization using multiple geometric representations. This enables us to show how fuzzy spectral clustering using uncertainty minimization is related to and generalizes clustering motivated by perturbative analysis of almost-block-diagonal matrices. Uncertainty minimization can be applied to a wide variety of existing hard spectral clustering approaches, thus transforming them to fuzzy methods.

  5. Spectral line polarimetry with a channeled polarimeter.

    Science.gov (United States)

    van Harten, Gerard; Snik, Frans; Rietjens, Jeroen H H; Martijn Smit, J; Keller, Christoph U

    2014-07-01

    Channeled spectropolarimetry or spectral polarization modulation is an accurate technique for measuring the continuum polarization in one shot with no moving parts. We show how a dual-beam implementation also enables spectral line polarimetry at the intrinsic resolution, as in a classic beam-splitting polarimeter. Recording redundant polarization information in the two spectrally modulated beams of a polarizing beam-splitter even provides the possibility to perform a postfacto differential transmission correction that improves the accuracy of the spectral line polarimetry. We perform an error analysis to compare the accuracy of spectral line polarimetry to continuum polarimetry, degraded by a residual dark signal and differential transmission, as well as to quantify the impact of the transmission correction. We demonstrate the new techniques with a blue sky polarization measurement around the oxygen A absorption band using the groundSPEX instrument, yielding a polarization in the deepest part of the band of 0.160±0.010, significantly different from the polarization in the continuum of 0.2284±0.0004. The presented methods are applicable to any dual-beam channeled polarimeter, including implementations for snapshot imaging polarimetry.

  6. The Sturm-Liouville inverse spectral problem with boundary conditions depending on the spectral parameter

    Directory of Open Access Journals (Sweden)

    Cornelis van der Mee

    2005-01-01

    Full Text Available We present the complete version including proofs of the results announced in [van der Mee C., Pivovarchik V.: A Sturm-Liouville spectral problem with boundary conditions depending on the spectral parameter. Funct. Anal. Appl. 36 (2002, 315–317 [Funkts. Anal. Prilozh. 36 (2002, 74–77 (Russian

  7. Metallicity and the spectral energy distribution and spectral types of dwarf O-stars

    NARCIS (Netherlands)

    Mokiem, M.R.; Martín-Hernández, N.L.; Lenorzer, A.; de Koter, A.; Tielens, A.G.G.M.

    2004-01-01

    We present a systematic study of the effect of metallicity on the stellar spectral energy distribution (SED) of O main sequence (dwarf) stars, focussing on the hydrogen and helium ionizing continua, and on the optical and near-IR lines used for spectral classification. The spectra are based on

  8. Spectral image reconstruction using an edge preserving spatio-spectral Wiener estimation.

    Science.gov (United States)

    Urban, Philipp; Rosen, Mitchell R; Berns, Roy S

    2009-08-01

    Reconstruction of spectral images from camera responses is investigated using an edge preserving spatio-spectral Wiener estimation. A Wiener denoising filter and a spectral reconstruction Wiener filter are combined into a single spatio-spectral filter using local propagation of the noise covariance matrix. To preserve edges the local mean and covariance matrix of camera responses is estimated by bilateral weighting of neighboring pixels. We derive the edge-preserving spatio-spectral Wiener estimation by means of Bayesian inference and show that it fades into the standard Wiener reflectance estimation shifted by a constant reflectance in case of vanishing noise. Simulation experiments conducted on a six-channel camera system and on multispectral test images show the performance of the filter, especially for edge regions. A test implementation of the method is provided as a MATLAB script at the first author's website.

  9. Spectral resolution measurement technique for Czerny-Turner spectrometers based on spectral interferometry

    Science.gov (United States)

    Contreras Martínez, Ramiro; Garduño Mejía, Jesús; Rosete Aguilar, Martha; Román Moreno, Carlos J.

    2016-08-01

    We propose the design of a new technique for measuring the spectral resolution of a Czerny-Turner Spectrometer based on spectral interferometry of ultrashort laser pulses. It is well known that ultrashort pulse measurement like SPIDER and TADPOLE techniques requires a precise and well characterized spectrum, especially in fringe resolution. We developed a new technique, to our knowledge, in which by measuring the nominal fringe spacing of a spectral interferogram one can characterize the spectral resolution in a Czerny-Turner spectrometer using Ryleigh's criteria. This technique was tested in a commercial Czerny-Turner spectrometer. The results demonstrate a consistent spectral resolution between what was reported by the manufacturer. The actual calibration technique was applied in a homemade broadband astigmatism-free Czerny-Turner spectrometer. Theory and experimental results are presented.

  10. Listening talkers produce great spectral tilt contrasts

    DEFF Research Database (Denmark)

    Christiansen, Thomas Ulrich; Heegård, Jan; Henrichsen, Peter Juel

    It is well known that the envelope of the long-term average speech spectrum flattens with vocal effort. A recent study [1] showed that content words had a flatter spectral envelope than content words at the same overall level for a specific Danish speech material. The present paper investigates...... of colored geometrical shapes taken from DanPASS [2]. The spectral tilt was gauged by calculating the band-level difference in dB between two frequency bands with pass-bands 150 to 803 Hz and 803 to 1358 Hz respectively in 5 ms intervals. This was done separately for intervals containing content words...... and function words and grouped by talker. The spectral tilt difference was then calculated as the average band-level difference for function words minus the average band-level difference for content words. This calculation was grouped per talker. For the monologues these differences ranged between 5 and 8 d...

  11. Automated spectral classification and the GAIA project

    Science.gov (United States)

    Lasala, Jerry; Kurtz, Michael J.

    1995-01-01

    Two dimensional spectral types for each of the stars observed in the global astrometric interferometer for astrophysics (GAIA) mission would provide additional information for the galactic structure and stellar evolution studies, as well as helping in the identification of unusual objects and populations. The classification of the large quantity generated spectra requires that automated techniques are implemented. Approaches for the automatic classification are reviewed, and a metric-distance method is discussed. In tests, the metric-distance method produced spectral types with mean errors comparable to those of human classifiers working at similar resolution. Data and equipment requirements for an automated classification survey, are discussed. A program of auxiliary observations is proposed to yield spectral types and radial velocities for the GAIA-observed stars.

  12. Spectrally resolved longitudinal spatial coherence inteferometry

    Science.gov (United States)

    Woodard, Ethan R.; Kudenov, Michael W.

    2017-05-01

    We present an alternative imaging technique using spectrally resolved longitudinal spatial coherence interferometry to encode a scene's angular information onto the source's power spectrum. Fourier transformation of the spectrally resolved channeled spectrum output yields a measurement of the incident scene's angular spectrum. Theory for the spectrally resolved interferometric technique is detailed, demonstrating analogies to conventional Fourier transform spectroscopy. An experimental proof of concept system and results are presented using an angularly-dependent Fabry-Perot interferometer-based optical design for successful reconstruction of one-dimensional sinusoidal angular spectra. Discussion for a potential future application of the technique, in which polarization information is encoded onto the source's power spectrum is also given.

  13. Multiple spectral splits of supernova neutrinos.

    Science.gov (United States)

    Dasgupta, Basudeb; Dighe, Amol; Raffelt, Georg G; Smirnov, Alexei Yu

    2009-07-31

    Collective oscillations of supernova neutrinos swap the spectra f(nu(e))(E) and f(nu[over ](e))(E) with those of another flavor in certain energy intervals bounded by sharp spectral splits. This phenomenon is far more general than previously appreciated: typically one finds one or more swaps and accompanying splits in the nu and nu[over ] channels for both inverted and normal neutrino mass hierarchies. Depending on an instability condition, swaps develop around spectral crossings (energies where f(nu(e))=f(nu(x)), f(nu[over ](e))=f(nu[over ](x)) as well as E-->infinity where all fluxes vanish), and the widths of swaps are determined by the spectra and fluxes. Washout by multiangle decoherence varies across the spectrum and splits can survive as sharp spectral features.

  14. Spectral Trends of Titan's Tropical Surface

    Science.gov (United States)

    Griffith, Caitlin Ann; Penteado, Paulo F.; Turner, Jake; Montiel, Nicholas; Schoenfeld, Ashley; Lopes, Rosaly M. C.; Soderblom, Laurence A.; Neish, Catherine; Radebaugh, Jani

    2016-10-01

    Titan's surface can be observed most clearly at 8 spectral regions that lie in between the strong methane bands in Titan's spectrum. Within these "windows", between 0.9 to 5 microns, the surface is nonetheless obscured by methane and haze, the latter of which is optically thick at lower wavelengths. Thus studies of Titan's surface must eliminate the effects of atmospheric extinction and extract the subtle spectral features that underlie the dominant spectral trends.To determine the subtle spectral features of Titan's tropical surface (30S--30N) we conducted a Principal Components Analysis (PCA) of the I/F at the 1.1, 1.3, 1.6 and 2.0 um wavelength windows, recorded by Cassini/VIMS. The PCA analysis identifies the spectral trend that defines the highest variance in the data (the principal component), as well as successively weaker orthogonal trends, without a priori assumptions about the surface composition, e.g. as needed in radiative transfer analyses.Our analysis derives the spectral features at the four wavelengths that describe Titan's tropical surface. We detect a large almost contiguous region that extends roughly 160 degrees in longitude and which exhibits absorption features at 1.6 and 2.0, as well as 2.8 um (characteristic of water ice). This vast and perhaps tectonic feature is, in part, associated with terrain that is hypothesized to be some of the oldest surfaces on Titan. In addition, the PCA analysis indicates at least 2 separate organic spectra signatures, potentially due to the separation of liquid and refractory sediments or to their chemically alteration over time. Here we discuss the PCA analysis and compare our derived compositional maps of Titan's surface with Radar maps of the topography and morphology, to entertain questions regarding the geology of Titan's surface the age of its atmosphere.

  15. Beam profile assessment in spectral CT scanners.

    Science.gov (United States)

    Anjomrouz, Marzieh; Shamshad, Muhammad; Panta, Raj K; Broeke, Lieza Vanden; Schleich, Nanette; Atharifard, Ali; Aamir, Raja; Bheesette, Srinidhi; Walsh, Michael F; Goulter, Brian P; Bell, Stephen T; Bateman, Christopher J; Butler, Anthony P H; Butler, Philip H

    2018-03-01

    In this paper, we present a method that uses a combination of experimental and modeled data to assess properties of x-ray beam measured using a small-animal spectral scanner. The spatial properties of the beam profile are characterized by beam profile shape, the angular offset along the rotational axis, and the photon count difference between experimental and modeled data at the central beam axis. Temporal stability of the beam profile is assessed by measuring intra- and interscan count variations. The beam profile assessment method was evaluated on several spectral CT scanners equipped with Medipix3RX-based detectors. On a well-calibrated spectral CT scanner, we measured an integral count error of 0.5%, intrascan count variation of 0.1%, and an interscan count variation of less than 1%. The angular offset of the beam center ranged from 0.8° to 1.6° for the studied spectral CT scanners. We also demonstrate the capability of this method to identify poor performance of the system through analyzing the deviation of the experimental beam profile from the model. This technique can, therefore, aid in monitoring the system performance to obtain a robust spectral CT; providing the reliable quantitative images. Furthermore, the accurate offset parameters of a spectral scanner provided by this method allow us to incorporate a more realistic form of the photon distribution in the polychromatic-based image reconstruction models. Both improvements of the reliability of the system and accuracy of the volume reconstruction result in a better discrimination and quantification of the imaged materials. © 2018 MARS Bioimaging Ltd. Journal of Applied Clinical Medical Physics published by Wiley Periodicals, Inc. on behalf of American Association of Physicists in Medicine.

  16. Universal fermionic spectral functions from string theory.

    Science.gov (United States)

    Gauntlett, Jerome P; Sonner, Julian; Waldram, Daniel

    2011-12-09

    We carry out the first holographic calculation of a fermionic response function for a strongly coupled d=3 system with an explicit D=10 or D=11 supergravity dual. By considering the supersymmetry current, we obtain a universal result applicable to all d=3 N=2 SCFTs with such duals. Surprisingly, the spectral function does not exhibit a Fermi surface, despite the fact that the system is at finite charge density. We show that it has a phonino pole and at low frequencies there is a depletion of spectral weight with a power-law scaling which is governed by a locally quantum critical point.

  17. Glue Film Thickness Measurements by Spectral Reflectance

    Energy Technology Data Exchange (ETDEWEB)

    B. R. Marshall

    2010-09-20

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 μm, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  18. Glue Film Thickness Measurements by Spectral Reflectance

    International Nuclear Information System (INIS)

    Marshall, B.R.

    2010-01-01

    Spectral reflectance was used to determine the thickness of thin glue layers in a study of the effect of the glue on radiance and reflectance measurements of shocked-tin substrates attached to lithium fluoride windows. Measurements based on profilometry of the components were found to be inaccurate due to flatness variations and deformation of the tin substrate under pressure during the gluing process. The accuracy of the spectral reflectance measurements were estimated to be ±0.5 (micro)m, which was sufficient to demonstrate a convincing correlation between glue thickness and shock-generated light.

  19. Quantum BCH Codes Based on Spectral Techniques

    International Nuclear Information System (INIS)

    Guo Ying; Zeng Guihua

    2006-01-01

    When the time variable in quantum signal processing is discrete, the Fourier transform exists on the vector space of n-tuples over the Galois field F 2 , which plays an important role in the investigation of quantum signals. By using Fourier transforms, the idea of quantum coding theory can be described in a setting that is much different from that seen that far. Quantum BCH codes can be defined as codes whose quantum states have certain specified consecutive spectral components equal to zero and the error-correcting ability is also described by the number of the consecutive zeros. Moreover, the decoding of quantum codes can be described spectrally with more efficiency.

  20. Spectral methods in numerical plasma simulation

    International Nuclear Information System (INIS)

    Coutsias, E.A.; Hansen, F.R.; Huld, T.; Knorr, G.; Lynov, J.P.

    1989-01-01

    An introduction is given to the use of spectral methods in numerical plasma simulation. As examples of the use of spectral methods, solutions to the two-dimensional Euler equations in both a simple, doubly periodic region, and on an annulus will be shown. In the first case, the solution is expanded in a two-dimensional Fourier series, while a Chebyshev-Fourier expansion is employed in the second case. A new, efficient algorithm for the solution of Poisson's equation on an annulus is introduced. Problems connected to aliasing and to short wavelength noise generated by gradient steepening are discussed. (orig.)

  1. Spectral Methods in Numerical Plasma Simulation

    DEFF Research Database (Denmark)

    Coutsias, E.A.; Hansen, F.R.; Huld, T.

    1989-01-01

    in a two-dimensional Fourier series, while a Chebyshev-Fourier expansion is employed in the second case. A new, efficient algorithm for the solution of Poisson's equation on an annulus is introduced. Problems connected to aliasing and to short wavelength noise generated by gradient steepening are discussed.......An introduction is given to the use of spectral methods in numerical plasma simulation. As examples of the use of spectral methods, solutions to the two-dimensional Euler equations in both a simple, doubly periodic region, and on an annulus will be shown. In the first case, the solution is expanded...

  2. Bedform characterization through 2D spectral analysis

    DEFF Research Database (Denmark)

    Lefebvre, Alice; Ernstsen, Verner Brandbyge; Winter, Christian

    2011-01-01

    characteristics using twodimensional (2D) spectral analysis is presented and tested on seabed elevation data from the Knudedyb tidal inlet in the Danish Wadden Sea, where large compound bedforms are found. The bathymetric data were divided into 20x20 m areas on which a 2D spectral analysis was applied. The most...... energetic peak of the 2D spectrum was found and its energy, frequency and direction were calculated. A power-law was fitted to the average of slices taken through the 2D spectrum; its slope and y-intercept were calculated. Using these results the test area was morphologically classified into 4 distinct...

  3. Krein Spectral Triples and the Fermionic Action

    International Nuclear Information System (INIS)

    Dungen, Koen van den

    2016-01-01

    Motivated by the space of spinors on a Lorentzian manifold, we define Krein spectral triples, which generalise spectral triples from Hilbert spaces to Krein spaces. This Krein space approach allows for an improved formulation of the fermionic action for almost-commutative manifolds. We show by explicit calculation that this action functional recovers the correct Lagrangians for the cases of electrodynamics, the electro-weak theory, and the Standard Model. The description of these examples does not require a real structure, unless one includes Majorana masses, in which case the internal spaces also exhibit a Krein space structure.

  4. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, C.; Ma, Y. H.; Zhao, H. B.; Lu, X. P.

    2016-09-01

    With the increasing asteroid spectral and photometric data, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations of Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. With the training data derived from the taxonomies of Tholen, Bus, Lazzaro, DeMeo, and Principal Component Analysis, we classify 48642 asteroids according to g, r, i, and z SDSS magnitudes. In this way, asteroids are divided into 8 spectral classes (C, X, S, B, D, K, L, and V).

  5. Spectral Analysis of Large Particle Systems

    DEFF Research Database (Denmark)

    Dahlbæk, Jonas

    2017-01-01

    is on obtaining a framework which unifies and generalizes frameworks that have appeared previously in the literature. The end result is a calculus for creation/annihilation symbols, where Wick’s theorem provides a formula for the product of finitely many symbols. The framework is then applied to the Fröhlich...... polaron model. The framework is also applied to the spin boson model. The application to the spin boson model is based on the spectral renormalization group. It is shown that the spectral renormalization group scheme can be natu- rally posed as an iterated Grushin problem. While it is already known...

  6. Bordism, stable homotopy and adams spectral sequences

    CERN Document Server

    Kochman, Stanley O

    1996-01-01

    This book is a compilation of lecture notes that were prepared for the graduate course "Adams Spectral Sequences and Stable Homotopy Theory" given at The Fields Institute during the fall of 1995. The aim of this volume is to prepare students with a knowledge of elementary algebraic topology to study recent developments in stable homotopy theory, such as the nilpotence and periodicity theorems. Suitable as a text for an intermediate course in algebraic topology, this book provides a direct exposition of the basic concepts of bordism, characteristic classes, Adams spectral sequences, Brown-Peter

  7. Novel spectral features of nanoelectromechanical systems

    KAUST Repository

    Tahir, M.

    2014-02-17

    Electron transport through a quantum dot or single molecule coupled to a quantum oscillator is studied by the Keldysh nonequilibrium Green\\'s function formalism to obtain insight into the quantum dynamics of the electronic and oscillator degrees of freedom. We tune the electronic level of the quantum dot by a gate voltage, where the leads are kept at zero temperature. Due to the nonequilibrium distribution of the electrons in the quantum dot, the spectral function becomes a function of the gate voltage. Novel spectral features are identified for the ground and excited states of nanomechanical oscillators that can be used to enhance the measurement sensitivity.

  8. Planck 2013 results. IX. HFI spectral response

    DEFF Research Database (Denmark)

    Planck Collaboration,; Ade, P. A. R.; Aghanim, N.

    2013-01-01

    -of-band signal rejection) of all HFI detectors to a known source of electromagnetic radiation individually. This was determined by measuring the output of all detection channels for radiation propagated through a continuously scanned polarizing Fourier transform spectrometer. As there is no on-board spectrometer......, this paper focuses on the analysis of the pre-flight spectral response measurements and the derivation of data products, e.g. band-average spectra, unit conversion coefficients, and colour correction coefficients, all with related uncertainties. Verifications of the HFI spectral response data are provided...

  9. Reducing the spectral index in supernatural inflation

    International Nuclear Information System (INIS)

    Lin, C.-M.; Cheung, Kingman

    2009-01-01

    Supernatural inflation is an attractive model based on just a flat direction with soft supersymmetry breaking mass terms in the framework of supersymmetry. The beauty of the model is that it needs no fine-tuning. However, the prediction of the spectral index is n s > or approx. 1, in contrast to experimental data. In this paper, we discuss supernatural inflation with the spectral index reduced to n s =0.96 without any fine-tuning, considering the general feature that a flat direction is lifted by a nonrenormalizable term with an A-term.

  10. Reducing the spectral index in supernatural inflation

    Science.gov (United States)

    Lin, Chia-Min; Cheung, Kingman

    2009-04-01

    Supernatural inflation is an attractive model based on just a flat direction with soft supersymmetry breaking mass terms in the framework of supersymmetry. The beauty of the model is that it needs no fine-tuning. However, the prediction of the spectral index is ns≳1, in contrast to experimental data. In this paper, we discuss supernatural inflation with the spectral index reduced to ns=0.96 without any fine-tuning, considering the general feature that a flat direction is lifted by a nonrenormalizable term with an A-term.

  11. Spectrally-Temporally Adapted Spectrally Modulated Spectrally Encoded (SMSE) Waveform Design for Coexistent CR-Based SDR Applications

    Science.gov (United States)

    2010-03-01

    Only and Spectrally-Temporally adapted SMSE signals at var - ious levels channel estimate MSE. Results based on a maximum BER constraint of PB = 10 −2...57. Tian, Z. and G. B. Giannakis. “A Wavelet Approach to Wideband Spectrum Sensing for Cognitive Radios”. Proceedings of the 1st International

  12. Prediction of traffic convective instability with spectral analysis of the Aw–Rascle–Zhang model

    Energy Technology Data Exchange (ETDEWEB)

    Belletti, Francois, E-mail: francois.belletti@berkeley.edu [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley (United States); Huo, Mandy, E-mail: mhuo@berkeley.edu [Department of Physics, University of California, Berkeley (United States); Department of Mathematics, University of California, Berkeley (United States); Litrico, Xavier, E-mail: xavier.litrico@lyonnaise-des-eaux.fr [LyRE, R& D center of SUEZ environnement, Bordeaux (France); Bayen, Alexandre M., E-mail: bayen@berkeley.edu [Department of Electrical Engineering and Computer Sciences, University of California, Berkeley (United States); Department of Civil and Environmental Engineering, University of California, Berkeley (United States); Institute of Transportation Studies, University of California, Berkeley (United States)

    2015-10-09

    Highlights: • We linearize and diagonalize the ARZ model. We give a Froude number for traffic. • Spectral domain transfer functions are derived and decompose the model. • The linearized system is convectively unstable in the free-flow regime. • We conduct experiments with the linearized model on the NGSIM dataset. • We show that the linearization does not destroy the accuracy of the model. - Abstract: This article starts from the classical Aw–Rascle–Zhang (ARZ) model for freeway traffic and develops a spectral analysis of its linearized version. A counterpart to the Froude number in hydrodynamics is defined that enables a classification of the nature of vehicle traffic flow using the explicit solution resulting from the analysis. We prove that our linearization about an equilibrium is stable for congested regimes and unstable otherwise. NGSIM data for congested traffic trajectories is used so as to confront the linearized model's predictions to actual macroscopic behavior of traffic. The model is shown to achieve good accuracy for speed and flow. In particular, it accounts for the advection of oscillations on boundaries into the interior domain where the PDE under study is solved.

  13. Spectral variability of 4U1145-619 during X-ray outburst

    International Nuclear Information System (INIS)

    Cook, M.C.; Warwick, R.S.

    1987-01-01

    A series of observations of the X-ray pulsar 4U1145-619 were performed by EXOSAT during successive X-ray outbursts on this source in 1984 July and 1985 January. On all occasions the source exhibited a very hard power-law X-ray spectrum (photon spectral index approx. 1.0) with a high-energy cut-off above approx. 6 keV. The low-energy cut-off in the X-ray spectrum, in contrast to the other spectral parameters, exhibited significant variations over the observations. Optical spectroscopy of the Be star Hen 715, identified as the optical counterpart of 4U1145-619, was performed during the 1985 January X-ray outburst. The resulting spectra revealed a marked decrease in the strength of the broad blue component of the dominant Hα emission line as the X-ray outburst progressed. There was, however, no evidence for any pulse phase dependency or short-term variability in either the Hα or Hβ emission lines. (author)

  14. Cis–Trans Configuration of Coumaric Acid Acylation Affects the Spectral and Colorimetric Properties of Anthocyanins

    Directory of Open Access Journals (Sweden)

    Gregory T. Sigurdson

    2018-03-01

    Full Text Available The color expression of anthocyanins can be affected by a variety of environmental factors and structural characteristics. Anthocyanin acylation (type and number of acids is known to be key, but the influence of acyl isomers (with unique stereochemistries remains to be explored. The objective of this study was to investigate the effects of cis–trans configuration of the acylating group on the spectral and colorimetric properties of anthocyanins. Petunidin-3-rutinoside-5-glucoside (Pt-3-rut-5-glu and Delphinidin-3-rutinoside-5-glucoside (Dp-3-rut-5-glu and their cis and trans coumaroylated derivatives were isolated from black goji and eggplant, diluted in pH 1–9 buffers, and analyzed spectrophotometrically (380–700 nm and colorimetrically (CIELAB during 72 h of storage (25 °C, dark. The stereochemistry of the acylating group strongly impacted the spectra, color, and stability of the Dp and Pt anthocyanins. Cis acylated pigments exhibited the greatest λmax in all pH, as much as 66 nm greater than their trans counterparts, showing bluer hues. Cis acylation seemed to reduce hydration across pH, increasing color intensity, while trans acylation generally improved color retention over time. Dp-3-cis-p-cou-rut-5-glu exhibited blue hues even in pH 5 (C*ab = 10, hab = 256° where anthocyanins are typically colorless. Cis or trans double bond configurations of the acylating group affected anthocyanin spectral and stability properties.

  15. Design of a Novel Spectral Albedometer for Validating the MODerate Resolution Imaging Spectroradiometer Spectral Albedo Product

    Directory of Open Access Journals (Sweden)

    Hongmin Zhou

    2018-01-01

    Full Text Available Land surface shortwave broadband albedo is a key parameter in general circulation models and surface energy budget models. Multispectral satellite data are typically used to generate broadband albedo products in a three-step process: atmospheric correction, for converting the top-of-atmosphere observations to surface directional reflectance; angular modeling, for converting the surface directional reflectance to spectral albedo of each individual band; and finally, narrowband-to-broadband conversion, for transforming the spectral albedos to broadband albedos. Spectroradiometers can be used for validating surface directional reflectance products and pyranometers or broadband albedometers, for validating broadband albedo products, but spectral albedo products are rarely validated using ground measurements. In this study, we designed a new type of albedometer that can measure spectral albedos. It consists of multiple interference filters and a silicon detector, for measuring irradiance from 400–1100 nm. The linearity of the sensors is 99%, and the designed albedometer exhibits consistency up to 0.993, with a widely-used commercial instrument. A field experiment for measuring spectral albedo of grassland using this new albedometer was conducted in Yudaokou, China and the measurements are used for validating the MODerate Resolution Imaging Spectroradiometer (MODIS spectral albedos. The results show that the biases of the MODIS spectral albedos of the first four bands are −0.0094, 0.0065, 0.0159, and −0.0001, respectively. This new instrument provides an effective technique for validating spectral albedos of any satellite sensor in this spectral range, which is critical for improving satellite broadband albedo products.

  16. Spectral evolution of gamma-ray bursts

    Science.gov (United States)

    Band, D.; Matteson, J.; Ford, L.; Schaefer, B.; Teegarden, B.; Cline, T.; Paciesas, W.; Pendleton, G.; Fishman, G.; Meegan, C.

    1992-01-01

    BATSE's Spectral Detectors provide a series of high resolution spectra over the duration of a gamma-ray burst; fits to these spectra show the evolution of the continuum as the burst progresses. The burst continuum can usually be fit by the spectral form AE sup alpha exp(-E/kT) from around 25 keV to more than 3 MeV, with varying trends in the value and evolution of the spectral parameters. As a result of limited statistics for E greater than 1 - 2 MeV in the individual spectra, a high energy power law is not required. Only long duration strong bursts can be studied by fitting a series of spectra, and therefore our conclusions concern only this class of burst. The bursts we analyzed tend to be characterized by a hard-to-soft trend both for individual intensity spikes and for the burst as a whole: the hardness leads the count rate in spectra which resolve the temporal variations, while the hardness of successive spikes decreases. We also summarize the performance of the Spectral Detectors and the development of analysis tools to date.

  17. On Spectral Triples in Quantum Gravity I

    DEFF Research Database (Denmark)

    Aastrup, Johannes; M. Grimstrup, Jesper; Nest, Ryszard

    2009-01-01

    This paper establishes a link between Noncommutative Geometry and canonical quantum gravity. A semi-finite spectral triple over a space of connections is presented. The triple involves an algebra of holonomy loops and a Dirac type operator which resembles a global functional derivation operator. ...

  18. Holonomy loops, spectral triples and quantum gravity

    DEFF Research Database (Denmark)

    Johannes, Aastrup; Grimstrup, Jesper Møller; Nest, Ryszard

    2009-01-01

    We review the motivation, construction and physical interpretation of a semi-finite spectral triple obtained through a rearrangement of central elements of loop quantum gravity. The triple is based on a countable set of oriented graphs and the algebra consists of generalized holonomy loops...

  19. Spectral triples and the geometry of fractals

    DEFF Research Database (Denmark)

    Christensen, Erik; Ivan, Cristina; Schroe, Elmar

    2012-01-01

    It is shown that one can construct a spectral triple for the Sierpinski gasket such that it represents any given K-homology class, On the other hand if the geodesic distance and the dimension has to be part of the data from the triple, there are certain restriction....

  20. Stellar Spectral Classification with Locality Preserving Projections ...

    Indian Academy of Sciences (India)

    type and 3 subclasses of F-type spectra from. Sloan Digital Sky Survey (SDSS). Lastly, the performance of LPP+SVM is compared with that of PCA+SVM in stellar spectral classification, and we found that LPP does better than PCA. Key words.

  1. Spectral analysis for differential operators with singularities

    Directory of Open Access Journals (Sweden)

    Vjacheslav Anatoljevich Yurko

    2004-01-01

    Full Text Available Nonselfadjoint boundary value problems for second-order differential equations on a finite interval with nonintegrable singularities inside the interval are considered under additional sewing conditions for solutions at the singular point. We study properties of the spectrum, prove the completeness of eigen- and associated functions, and investigate the inverse problem of recovering the boundary value problem from its spectral characteristics.

  2. Synthesis, spectral characterization and in vitro antibacterial ...

    African Journals Online (AJOL)

    Shafqat Nadeem

    2015-12-17

    Dec 17, 2015 ... Petra/Osiris/Molinspiration analysis. Abstract The paper emphasizes on the synthesis of Palladium(II) iodide complexes containing based ligands. The new compounds .... The spectral conditions were as follows: 32 K data points,. 1.822 s acquisition time, 2.00 s pulse delay and 6.00 ls pulse width. The 13C ...

  3. Prediction formula for the spectral wave period

    NARCIS (Netherlands)

    Hofland, B.; Chen, X.; Altomare, Corrado; Oosterlo, P.

    2017-01-01

    During the last decades, the spectral wave period Tm-1,0 has become accepted as a characteristic wave period when describing the hydraulic attack on coastal structures, especially over shallow foreshores. In this study, we derive an empirical prediction formula for

  4. Low-Cost Spectral Sensor Development Description.

    Energy Technology Data Exchange (ETDEWEB)

    Armijo, Kenneth Miguel; Yellowhair, Julius

    2014-11-01

    Solar spectral data for all parts of the US is limited due in part to the high cost of commercial spectrometers. Solar spectral information is necessary for accurate photovoltaic (PV) performance forecasting, especially for large utility-scale PV installations. A low-cost solar spectral sensor would address the obstacles and needs. In this report, a novel low-cost, discrete- band sensor device, comprised of five narrow-band sensors, is described. The hardware is comprised of commercial-off-the-shelf components to keep the cost low. Data processing algorithms were developed and are being refined for robustness. PV module short-circuit current ( I sc ) prediction methods were developed based on interaction-terms regression methodology and spectrum reconstruction methodology for computing I sc . The results suggest the computed spectrum using the reconstruction method agreed well with the measured spectrum from the wide-band spectrometer (RMS error of 38.2 W/m 2 -nm). Further analysis of computed I sc found a close correspondence of 0.05 A RMS error. The goal is for ubiquitous adoption of the low-cost spectral sensor in solar PV and other applications such as weather forecasting.

  5. Spectral Radius and Hamiltonicity of Graphs

    Czech Academy of Sciences Publication Activity Database

    Fiedler, Miroslav; Nikiforov, V.

    2010-01-01

    Roč. 432, č. 9 (2010), s. 2170-2173 ISSN 0024-3795 Institutional research plan: CEZ:AV0Z10300504 Keywords : Hamiltonian cycle * Hamiltonian path * spectral radius Subject RIV: BA - General Mathematics Impact factor: 1.005, year: 2010

  6. Sparsity and spectral properties of dual frames

    DEFF Research Database (Denmark)

    Krahmer, Felix; Kutyniok, Gitta; Lemvig, Jakob

    2013-01-01

    We study sparsity and spectral properties of dual frames of a given finite frame. We show that any finite frame has a dual with no more than $n^2$ non-vanishing entries, where $n$ denotes the ambient dimension, and that for most frames no sparser dual is possible. Moreover, we derive an expressio...

  7. SYNTHESIS, SPECTRAL AND THERMAL PROPERTIES OF SOME ...

    African Journals Online (AJOL)

    The infrared spectral studies reveal that the ligand HNAAPTS is coordinated in neutral tridentate (N,N,S) fashion. The coordination number of Th(IV) in these coordination compounds varies from 6, 8, 10 or 11; while for U(VI) the coordination number are 8, 9 or 10. Thermal stabilities of these complexes were investigated ...

  8. Spectral Gaps in Graphene Antidot Lattices

    DEFF Research Database (Denmark)

    Barbaroux, Jean-Marie; Cornean, Decebal Horia; Stockmeyer, Edgardo

    2017-01-01

    We consider the gap creation problem in an antidot graphene lattice, i.e. a sheet of graphene with periodically distributed obstacles. We prove several spectral results concerning the size of the gap and its dependence on different natural parameters related to the antidot lattice....

  9. Some spectral equivalences between Schroedinger operators

    International Nuclear Information System (INIS)

    Dunning, C; Hibberd, K E; Links, J

    2008-01-01

    Spectral equivalences of the quasi-exactly solvable sectors of two classes of Schroedinger operators are established, using Gaudin-type Bethe ansatz equations. In some instances the results can be extended leading to full isospectrality. In this manner we obtain equivalences between PT-symmetric problems and Hermitian problems. We also find equivalences between some classes of Hermitian operators

  10. The 3XMM spectral fit database

    Science.gov (United States)

    Georgantopoulos, I.; Corral, A.; Watson, M.; Carrera, F.; Webb, N.; Rosen, S.

    2016-06-01

    I will present the XMMFITCAT database which is a spectral fit inventory of the sources in the 3XMM catalogue. Spectra are available by the XMM/SSC for all 3XMM sources which have more than 50 background subtracted counts per module. This work is funded in the framework of the ESA Prodex project. The 3XMM catalog currently covers 877 sq. degrees and contains about 400,000 unique sources. Spectra are available for over 120,000 sources. Spectral fist have been performed with various spectral models. The results are available in the web page http://xraygroup.astro.noa.gr/ and also at the University of Leicester LEDAS database webpage ledas-www.star.le.ac.uk/. The database description as well as some science results in the joint area with SDSS are presented in two recent papers: Corral et al. 2015, A&A, 576, 61 and Corral et al. 2014, A&A, 569, 71. At least for extragalactic sources, the spectral fits will acquire added value when photometric redshifts become available. In the framework of a new Prodex project we have been funded to derive photometric redshifts for the 3XMM sources using machine learning techniques. I will present the techniques as well as the optical near-IR databases that will be used.

  11. Spectral methods applied to Ising models

    International Nuclear Information System (INIS)

    DeFacio, B.; Hammer, C.L.; Shrauner, J.E.

    1980-01-01

    Several applications of Ising models are reviewed. A 2-d Ising model is studied, and the problem of describing an interface boundary in a 2-d Ising model is addressed. Spectral methods are used to formulate a soluble model for the surface tension of a many-Fermion system

  12. Fingerprint Verification Using Spectral Minutiae Representations

    NARCIS (Netherlands)

    Xu, H.; Veldhuis, Raymond N.J.; Bazen, A.M.; Kevenaar, Tom A.M.; Akkermans, Ton A.H.M.; Gökberk, B.

    2009-01-01

    Most fingerprint recognition systems are based on the use of a minutiae set, which is an unordered collection of minutiae locations and orientations suffering from various deformations such as translation, rotation, and scaling. The spectral minutiae representation introduced in this paper is a

  13. Power Spectral Density Conversions and Nonlinear Dynamics

    Directory of Open Access Journals (Sweden)

    Mostafa Rassaian

    1994-01-01

    Full Text Available To predict the vibration environment of a payload carried by a ground or air transporter, mathematical models are required from which a transfer function to a prescribed input can be calculated. For sensitive payloads these models typically include linear shock isolation system stiffness and damping elements relying on the assumption that the isolation system has a predetermined characteristic frequency and damping ratio independent of excitation magnitude. In order to achieve a practical spectral analysis method, the nonlinear system has to be linearized when the input transportation and handling vibration environment is in the form of an acceleration power spectral density. Test data from commercial isolators show that when nonlinear stiffness and damping effects exist the level of vibration input causes a variation in isolator resonant frequency. This phenomenon, described by the stationary response of the Duffing oscillator to narrow-band Gaussian random excitation, requires an alternative approach for calculation of power spectral density acceleration response at a shock isolated payload under random vibration. This article details the development of a plausible alternative approach for analyzing the spectral response of a nonlinear system subject to random Gaussian excitations.

  14. ICRAF-ISRIC Soil VNIR Spectral Library

    NARCIS (Netherlands)

    Batjes, N.H.

    2014-01-01

    The ICRAF-ISRIC Soil VNIR Spectral Library contains visible near infrared spectra of 4,438 soils selected from the Soil Information System (ISIS) of the International Soil Reference and Information Centre (ISRIC). The samples consist of all physically archived samples at ISRIC in 2004 for which soil

  15. Electrophysiological measurements of spectral sensitivities: a review

    Directory of Open Access Journals (Sweden)

    R.D. DeVoe

    1997-02-01

    Full Text Available Spectral sensitivities of visual systems are specified as the reciprocals of the intensities of light (quantum fluxes needed at each wavelength to elicit the same criterion amplitude of responses. This review primarily considers the methods that have been developed for electrophysiological determinations of criterion amplitudes of slow-wave responses from single retinal cells. Traditional flash methods can require tedious dark adaptations and may yield erroneous spectral sensitivity curves which are not seen in such modifications as ramp methods. Linear response methods involve interferometry, while constant response methods involve manual or automatic adjustments of continuous illumination to keep response amplitudes constant during spectral scans. In DC or AC computerized constant response methods, feedback to determine intensities at each wavelength is derived from the response amplitudes themselves. Although all but traditional flash methods have greater or lesser abilities to provide on-line determinations of spectral sensitivities, computerized constant response methods are the most satisfactory due to flexibility, speed and maintenance of a constant adaptation level

  16. Women's preferences of dynamic spectral imaging colposcopy

    NARCIS (Netherlands)

    Louwers, J.A.; Zaal, Afra; Kocken, M.; Papagiannakis, E.; Meijer, C.J.; Verheijen, RHM

    2015-01-01

    Background: The focus of testing the dynamic spectral imaging (DSI) colposcope has been on the technical characteristics and clinical performance. However, aspects from a patient’s perspective are just as important. Methods: This study was designed as a substudy of the DSI validation study, a

  17. Synthesis, spectral, thermal, optical dispersion and dielectric ...

    Indian Academy of Sciences (India)

    2016-08-26

    Aug 26, 2016 ... Home; Journals; Bulletin of Materials Science; Volume 39; Issue 1. Synthesis, spectral, thermal, optical dispersion and dielectric properties of nanocrystalline dimer complex (PEPyr–diCd) thin films as novel organic semiconductor. Ahmed Farouk Al-Hossainy. Volume 39 Issue 1 February 2016 pp 209-222 ...

  18. Testing a missing spectral link in turbulence

    NARCIS (Netherlands)

    Kellay, H.; Tran, Tuan; Goldburg, W.; Goldenfeld, N.; Gioia, G.; Chakraborty, P.

    2012-01-01

    Although the cardinal attribute of turbulence is the velocity fluctuations, these fluctuations have been ignored in theories of the frictional drag of turbulent flows. Our goal is to test a new theory that links the frictional drag to the spectral exponent , a property of the velocity fluctuations

  19. Fast Fourier Transform Spectral Analysis Program

    Science.gov (United States)

    Daniel, J. A., Jr.; Graves, M. L.; Hovey, N. M.

    1969-01-01

    Fast Fourier Transform Spectral Analysis Program is used in frequency spectrum analysis of postflight, space vehicle telemetered trajectory data. This computer program with a digital algorithm can calculate power spectrum rms amplitudes and cross spectrum of sampled parameters at even time increments.

  20. TP89 - SIRZ Decomposition Spectral Estimation

    Energy Technology Data Exchange (ETDEWEB)

    Seetho, Isacc M. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Azevedo, Steve [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Smith, Jerel [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Brown, William D. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States); Martz, Jr., Harry E. [Lawrence Livermore National Lab. (LLNL), Livermore, CA (United States)

    2016-12-08

    The primary objective of this test plan is to provide X-ray CT measurements of known materials for the purposes of generating and testing MicroCT and EDS spectral estimates. These estimates are to be used in subsequent Ze/RhoE decomposition analyses of acquired data.

  1. Aspiring to Spectral Ignorance in Earth Observation

    Science.gov (United States)

    Oliver, S. A.

    2016-12-01

    Enabling robust, defensible and integrated decision making in the Era of Big Earth Data requires the fusion of data from multiple and diverse sensor platforms and networks. While the application of standardised global grid systems provides a common spatial analytics framework that facilitates the computationally efficient and statistically valid integration and analysis of these various data sources across multiple scales, there remains the challenge of sensor equivalency; particularly when combining data from different earth observation satellite sensors (e.g. combining Landsat and Sentinel-2 observations). To realise the vision of a sensor ignorant analytics platform for earth observation we require automation of spectral matching across the available sensors. Ultimately, the aim is to remove the requirement for the user to possess any sensor knowledge in order to undertake analysis. This paper introduces the concept of spectral equivalence and proposes a methodology through which equivalent bands may be sourced from a set of potential target sensors through application of equivalence metrics and thresholds. A number of parameters can be used to determine whether a pair of spectra are equivalent for the purposes of analysis. A baseline set of thresholds for these parameters and how to apply them systematically to enable relation of spectral bands amongst numerous different sensors is proposed. The base unit for comparison in this work is the relative spectral response. From this input, determination of a what may constitute equivalence can be related by a user, based on their own conceptualisation of equivalence.

  2. Spectral Compressive Sensing with Polar Interpolation

    DEFF Research Database (Denmark)

    Fyhn, Karsten; Dadkhahi, Hamid; F. Duarte, Marco

    2013-01-01

    Existing approaches to compressive sensing of frequency-sparse signals focuses on signal recovery rather than spectral estimation. Furthermore, the recovery performance is limited by the coherence of the required sparsity dictionaries and by the discretization of the frequency parameter space...

  3. Spectral solution of the inverse Mie problem

    Science.gov (United States)

    Romanov, Andrey V.; Konokhova, Anastasiya I.; Yastrebova, Ekaterina S.; Gilev, Konstantin V.; Strokotov, Dmitry I.; Chernyshev, Andrei V.; Maltsev, Valeri P.; Yurkin, Maxim A.

    2017-10-01

    We developed a fast method to determine size and refractive index of homogeneous spheres from the power Fourier spectrum of their light-scattering patterns (LSPs), measured with the scanning flow cytometer. Specifically, we used two spectral parameters: the location of the non-zero peak and zero-frequency amplitude, and numerically inverted the map from the space of particle characteristics (size and refractive index) to the space of spectral parameters. The latter parameters can be reliably resolved only for particle size parameter greater than 11, and the inversion is unique only in the limited range of refractive index with upper limit between 1.1 and 1.25 (relative to the medium) depending on the size parameter and particular definition of uniqueness. The developed method was tested on two experimental samples, milk fat globules and spherized red blood cells, and resulted in accuracy not worse than the reference method based on the least-square fit of the LSP with the Mie theory. Moreover, for particles with significant deviation from the spherical shape the spectral method was much closer to the Mie-fit result than the estimated uncertainty of the latter. The spectral method also showed adequate results for synthetic LSPs of spheroids with aspect ratios up to 1.4. Overall, we present a general framework, which can be used to construct an inverse algorithm for any other experimental signals.

  4. Synthesis and Spectral Characterization of Some New ...

    African Journals Online (AJOL)

    NJD

    O=P and N-H....O=C hydrogen bonds in1aand4b, respectively. In all the synthesized molecules, similar spectral patterns were obtained in the 13C NMR spectra for carbon atoms of cyclic amines with 2JPNC = 0 and 3JPNC ranging from 4 to 6 Hz. KEYWORDS. Carbacylamidophosphates, hydrogen bonds, IR spectroscopy, ...

  5. Improvement of electrophoresis performance by spectral analysis ...

    African Journals Online (AJOL)

    This paper describes a new design of standard agarose gel electrophoresis procedure for nucleic acids analysis. The electrophoresis was improved by using the real-time spectral analysis of the samples to increase its performance. A laser beam illuminated the analysed sample at wavelength with the highest absorption of ...

  6. Spectral Representations of Fingerprint Minutiae Subsets

    NARCIS (Netherlands)

    Xu, H.; Veldhuis, Raymond N.J.

    2009-01-01

    The investigation of the privacy protection of biometric templates gains more and more attention. The spectral minutiae representation is a novel method to represent a minutiae set as a fixed-length feature vector, which is invariant to translation, and in which rotation and scaling become

  7. SpecViz: Interactive Spectral Data Analysis

    Science.gov (United States)

    Earl, Nicholas Michael; STScI

    2016-06-01

    The astronomical community is about to enter a new generation of scientific enterprise. With next-generation instrumentation and advanced capabilities, the need has arisen to equip astronomers with the necessary tools to deal with large, multi-faceted data. The Space Telescope Science Institute has initiated a data analysis forum for the creation, development, and maintenance of software tools for the interpretation of these new data sets. SpecViz is a spectral 1-D interactive visualization and analysis application built with Python in an open source development environment. A user-friendly GUI allows for a fast, interactive approach to spectral analysis. SpecViz supports handling of unique and instrument-specific data, incorporation of advanced spectral unit handling and conversions in a flexible, high-performance interactive plotting environment. Active spectral feature analysis is possible through interactive measurement and statistical tools. It can be used to build wide-band SEDs, with the capability of combining or overplotting data products from various instruments. SpecViz sports advanced toolsets for filtering and detrending spectral lines; identifying, isolating, and manipulating spectral features; as well as utilizing spectral templates for renormalizing data in an interactive way. SpecViz also includes a flexible model fitting toolset that allows for multi-component models, as well as custom models, to be used with various fitting and decomposition routines. SpecViz also features robust extension via custom data loaders and connection to the central communication system underneath the interface for more advanced control. Incorporation with Jupyter notebooks via connection with the active iPython kernel allows for SpecViz to be used in addition to a user’s normal workflow without demanding the user drastically alter their method of data analysis. In addition, SpecViz allows the interactive analysis of multi-object spectroscopy in the same straight

  8. The spectral irradiance traceability chain at PTB

    International Nuclear Information System (INIS)

    Sperfeld, P.; Pape, S.; Nevas, S.

    2013-01-01

    Spectral irradiance is a fundamental radiometric unit. Its application to measurement results requires qualified traceability to basic units of the international system of units (Système international d’unités, SI). The Physikalisch-Technische Bundesanstalt (PTB) is amongst other national metrological institutes (NMIs) responsible for the realization, maintenance and dissemination of various radiometric and photometric units based on and traceable to national standards. The unit of spectral irradiance is realized and represented by a blackbody-radiator as the national primary standard of the PTB. Based on Planck’s radiation law, the irradiance is calculated and realized for any wavelength taking into account the exact knowledge of the radiation temperature and the geometrical parameters. Using a double-monochromator-based spectroradiometer system, secondary standard lamps can be calibrated by direct comparison to the blackbody-radiator (substitution method). These secondary standard lamps are then used at the PTB to calibrate standard lamps of customers. The customers themselves use these so-called transfer standards to calibrate their working standard lamps. These working standards are then used to calibrate own spectroradiometers or sources. This rather complex calibration chain is a common procedural method that for the customers generally leads to satisfying measurement results on site. Nevertheless, the standard lamps in use have to fulfill highest requirements concerning stability and reproducibility. Only this allows achieving comparably low transfer measurement uncertainties, which occur at each calibration step. Thus, the PTB is constantly investigating the improvement and further development of transfer standards and measurement methods for various spectral regions. The realization and dissemination of the spectral irradiance using the blackbody-radiator at the PTB is accomplished with worldwide approved minimized measurement uncertainties confirmed

  9. The Open Spectral Database: an open platform for sharing and searching spectral data

    OpenAIRE

    Chalk, Stuart J.

    2016-01-01

    Background A number of websites make available spectral data for download (typically as JCAMP-DX text files) and one (ChemSpider) that also allows users to contribute spectral files. As a result, searching and retrieving such spectral data can be time consuming, and difficult to reuse if the data is compressed in the JCAMP-DX file. What is needed is a single resource that allows submission of JCAMP-DX files, export of the raw data in multiple formats, searching based on multiple chemical iden...

  10. Assessment of spectral and temporal resolution in cochlear implant users using psychoacoustic discrimination and speech cue categorization

    Science.gov (United States)

    Winn, Matthew B.; Won, Jong Ho; Moon, Il Joon

    2016-01-01

    categorization of the controlled speech cues than with performance on the psychophysical discrimination tasks. Conclusions When evaluating people with cochlear implants, controlled speech-based stimuli are feasible to use in tests of auditory cue categorization, to complement traditional measures of auditory discrimination. Stimuli based on specific speech cues correspond to counterpart non-linguistic measures of discrimination, but potentially show better correspondence with speech perception more generally. The ubiquity of the spectral (formant transition) and temporal (VOT) stimulus dimensions across languages highlights the potential to use this testing approach even in cases where English is not the native language. PMID:27438871

  11. Digital staining for histopathology multispectral images by the combined application of spectral enhancement and spectral transformation.

    Science.gov (United States)

    Bautista, Pinky A; Yagi, Yukako

    2011-01-01

    In this paper we introduced a digital staining method for histopathology images captured with an n-band multispectral camera. The method consisted of two major processes: enhancement of the original spectral transmittance and the transformation of the enhanced transmittance to its target spectral configuration. Enhancement is accomplished by shifting the original transmittance with the scaled difference between the original transmittance and the transmittance estimated with m dominant principal component (PC) vectors;the m-PC vectors were determined from the transmittance samples of the background image. Transformation of the enhanced transmittance to the target spectral configuration was done using an nxn transformation matrix, which was derived by applying a least square method to the enhanced and target spectral training data samples of the different tissue components. Experimental results on the digital conversion of a hematoxylin and eosin (H&E) stained multispectral image to its Masson's trichrome stained (MT) equivalent shows the viability of the method.

  12. KK -theory and spectral flow in von Neumann algebras

    DEFF Research Database (Denmark)

    Kaad, Jens; Nest, Ryszard; Rennie, Adam

    2012-01-01

    We present a definition of spectral flow for any norm closed ideal J in any von Neumann algebra N. Given a path of selfadjoint operators in N which are invertible in N/J, the spectral flow produces a class in Ko (J). Given a semifinite spectral triple (A, H, D) relative to (N, t) with A separable......, we construct a class [D] ¿ KK1 (A, K(N)). For a unitary u ¿ A, the von Neumann spectral flow between D and u*Du is equal to the Kasparov product [u] A[D], and is simply related to the numerical spectral flow, and a refined C* -spectral flow....

  13. Optimization design of spectral discriminator for high-spectral-resolution lidar based on error analysis.

    Science.gov (United States)

    Di, Huige; Zhang, Zhanfei; Hua, Hangbo; Zhang, Jiaqi; Hua, Dengxin; Wang, Yufeng; He, Tingyao

    2017-03-06

    Accurate aerosol optical properties could be obtained via the high spectral resolution lidar (HSRL) technique, which employs a narrow spectral filter to suppress the Rayleigh or Mie scattering in lidar return signals. The ability of the filter to suppress Rayleigh or Mie scattering is critical for HSRL. Meanwhile, it is impossible to increase the rejection of the filter without limitation. How to optimize the spectral discriminator and select the appropriate suppression rate of the signal is important to us. The HSRL technology was thoroughly studied based on error propagation. Error analyses and sensitivity studies were carried out on the transmittance characteristics of the spectral discriminator. Moreover, ratwo different spectroscopic methods for HSRL were described and compared: one is to suppress the Mie scattering; the other is to suppress the Rayleigh scattering. The corresponding HSRLs were simulated and analyzed. The results show that excessive suppression of Rayleigh scattering or Mie scattering in a high-spectral channel is not necessary if the transmittance of the spectral filter for molecular and aerosol scattering signals can be well characterized. When the ratio of transmittance of the spectral filter for aerosol scattering and molecular scattering is less than 0.1 or greater than 10, the detection error does not change much with its value. This conclusion implies that we have more choices for the high-spectral discriminator in HSRL. Moreover, the detection errors of HSRL regarding the two spectroscopic methods vary greatly with the atmospheric backscattering ratio. To reduce the detection error, it is necessary to choose a reasonable spectroscopic method. The detection method of suppressing the Rayleigh signal and extracting the Mie signal can achieve less error in a clear atmosphere, while the method of suppressing the Mie signal and extracting the Rayleigh signal can achieve less error in a polluted atmosphere.

  14. STUDY OF CHARACTERISTICS OF SPECTRAL INTERFERENCE SIGNALS IN THE NEAR INFRARED SPECTRAL RANGE

    Directory of Open Access Journals (Sweden)

    I. P. Gurov

    2014-01-01

    Full Text Available Peculiarities of signals formation in spectral interferometry and optical coherence tomography are considered. Basic relations are given defining minimal depth coordinate value of an investigated object, where single period of spectral interference signal is acquired and a value of the wave length increment set according to the depth range, where spectral interference signals are registered. The estimate of resolving power of the spectral interfereometry and optical coherence tomography systems with tunable wave length is given taking into account a spectral range of wave length tuning. It is shown that the ratio of the wave length mean value and the range of the wave length tuning defines the resolving power in depth of an investigated object, while the maximum depth range, within which investigation of an object’s micro structure by the spectral optical coherence tomography is possible does not depend on the range of the wave length tuning being determined by the wave length (wave number tuning step. Numerical estimates of the parameters mentioned above are presented when using light sources in near infrared range, as well as relations and estimates of interference fringe visibility dependent on registered relative intensity of a measuring wave.

  15. (LMRG): Microscope Resolution, Objective Quality, Spectral Accuracy and Spectral Un-mixing

    Science.gov (United States)

    Bayles, Carol J.; Cole, Richard W.; Eason, Brady; Girard, Anne-Marie; Jinadasa, Tushare; Martin, Karen; McNamara, George; Opansky, Cynthia; Schulz, Katherine; Thibault, Marc; Brown, Claire M.

    2012-01-01

    The second study by the LMRG focuses on measuring confocal laser scanning microscope (CLSM) resolution, objective lens quality, spectral imaging accuracy and spectral un-mixing. Affordable test samples for each aspect of the study were designed, prepared and sent to 116 labs from 23 countries across the globe. Detailed protocols were designed for the three tests and customized for most of the major confocal instruments being used by the study participants. One protocol developed for measuring resolution and objective quality was recently published in Nature Protocols (Cole, R. W., T. Jinadasa, et al. (2011). Nature Protocols 6(12): 1929–1941). The first study involved 3D imaging of sub-resolution fluorescent microspheres to determine the microscope point spread function. Results of the resolution studies as well as point spread function quality (i.e. objective lens quality) from 140 different objective lenses will be presented. The second study of spectral accuracy looked at the reflection of the laser excitation lines into the spectral detection in order to determine the accuracy of these systems to report back the accurate laser emission wavelengths. Results will be presented from 42 different spectral confocal systems. Finally, samples with double orange beads (orange core and orange coating) were imaged spectrally and the imaging software was used to un-mix fluorescence signals from the two orange dyes. Results from 26 different confocal systems will be summarized. Time will be left to discuss possibilities for the next LMRG study.

  16. Real-Time Optical Flux Limits from Gamma-Ray Bursts Measured by the Gamma-Ray Optical Counterpart Search Experiment

    Science.gov (United States)

    Park, H. S. (Editor); Ables, E. (Editor); Band, D. L. (Editor); Barthelmy, S. D. (Editor); Bionta, R. M. (Editor); Butterworth, P. S. (Editor); Cline, T. L. (Editor); Ferguson, D. H. (Editor); Fishman, G. J. (Editor); Gehrels, N. (Editor); hide

    1997-01-01

    The Gamma-Ray Optical Counterpart Search Experiment presents new experimental upper limits on the optical flux from gamma-ray bursts (GRBs). Our experiment consisted of a fully automated very wide-field opto-electronic detection system that imaged locations of GRBs within a few seconds of receiving trigger signals provided by BATSE's real-time burst coordinate distribution network. The experiment acquired 3800 observing hours, recording 22 gamma-ray burst triggers within approx. 30 s of the start of the burst event. Some of these bursts were imaged while gamma-ray radiation was being detected by BATSE. We identified no optical counterparts associated with gamma-ray bursts among these events at the mV approx. 7.0-8.3 sensitivity level. We find the ratio of the upper limit to the V-band optical flux, F nu, to the gamma-ray fluence, Phi gamma, from these data to be 1 x 10(exp-18) less than F nu Phi gamma less than 2 x 10(exp -16).

  17. Inverse Compton Scattered Merger-nova: Late X-Ray Counterpart of Gravitational-wave Signals from NS–NS/BH Mergers

    Science.gov (United States)

    Ai, Shunke; Gao, He

    2018-01-01

    The recent observations of GW170817 and its electromagnetic (EM) counterparts show that double neutron star mergers could lead to rich and bright EM emissions. Recent numerical simulations suggest that neutron star and neutron star/black hole (NS–NS/BH) mergers would leave behind a central remnant surrounded by a mildly isotropic ejecta. The central remnant could launch a collimated jet and when the jet propagates through the ejecta, a mildly relativistic cocoon would be formed and the interaction between the cocoon and the ambient medium would accelerate electrons via external shock in a wide angle, so that the merger-nova photons (i.e., thermal emission from the ejecta) would be scattered into higher frequency via an inverse Compton (IC) process when they propagate through the cocoon shocked region. We find that the IC scattered component peaks at the X-ray band and it will reach its peak luminosity on the order of days (simultaneously with the merger-nova emission). With current X-ray detectors, such a late X-ray component could be detected out to 200 Mpc, depending on the merger remnant properties. It could serve as an important electromagnetic counterpart of gravitational-wave signals from NS–NS/BH mergers. Nevertheless, simultaneous detection of such a late X-ray signal and the merger-nova signal could shed light on the cocoon properties and the concrete structure of the jet.

  18. Molecular alterations in lesions of anogenital mammary-like glands and their mammary counterparts including hidradenoma papilliferum, intraductal papilloma, fibroadenoma and phyllodes tumor.

    Science.gov (United States)

    Konstantinova, Anastasia M; Vanecek, Tomas; Martinek, Petr; Kyrpychova, Liubov; Spagnolo, Dominic V; Stewart, Colin J R; Portelli, Francesca; Michal, Michal; Kazakov, Dmitry V

    2017-06-01

    Lesions affecting anogenital mammary-like glands (AGMLG) are histopathologically very similar to those seen in the breast but whether this morphological similarity is also reflected at the genetic level is unknown. To compare the underlying molecular mechanisms in lesions of AGMLG and their mammary counterparts, we analyzed the mutational profile of 16 anogenital neoplasms including 5 hidradenomas papilliferum (HP), 1 lesion with features of HP and fibroadenoma (FA), 7 FA, 3 phyllodes tumors (PhT)) and 18 analogous breast lesions (6 intraductal papillomas (IDP), 9 FA, and 3 PhT) by high-coverage next generation sequencing (NGS) using a panel comprising 50 cancer-related genes. Additionally, all cases were analyzed for the presence of a mutation in the MED12 gene. All detected mutations with allele frequencies over 20% were independently validated by Sanger sequencing (concordance: 100%). Mutations in PIK3CA, AKT1, MET, ABL1 and TP53 genes were found in lesions of AGMLG and also their mammary counterparts. The PI3K-AKT cascade plays a role in tumors arising at both sites. It appears that some histopathologically similar anogenital and breast lesions develop along similar molecular pathways. Copyright © 2017 Elsevier Inc. All rights reserved.

  19. Comparison of visual working memory in deaf and hearing-impaired students with normal counterparts: A research in people without sign language

    Directory of Open Access Journals (Sweden)

    Farideh Tangestani Zadeh

    2015-02-01

    Full Text Available Background and Aim: The hearing defects in deaf and hearing-impaired students also affect their cognitive skills such as memory in addition to communication skills. Hence, the aim of this study was to compare visual working memory in deaf and hearing-impaired students with that in normal counterparts.Method: In the present study, which was a causal-comparative study using the André Rey test, 30 deaf and 30 hearing-impaired students were compared with 30 students in a normal group, and they were matched based on gender, intelligence, educational grade, and socioeconomic status.Findings: Findings show that there is significant difference between the three groups’ subjects (p0.05.Conclusion: Function of deaf or hard-of-hearing students in the visual working memory task was weaker in comparison with the normal counterparts, while the two deaf and hard-of-hearing groups have similar functions. With a better identification and understanding of the factors that affect the development of this cognitive ability, we can offer new methods of teaching and reduce many of the disadvantages of this group of people in the different fields of cognitive science.

  20. XMM-Newton Observations Reveal the X-ray Counterpart of the Very-high-energy gamma-ray Source HESS J1640-465

    Energy Technology Data Exchange (ETDEWEB)

    Funk, S.; Hinton, J.A.; Puhlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.; /KIPAC, Menlo Park /Heidelberg, Max Planck Inst. /Leeds U. /Dublin Inst. /Stanford U., HEPL; Funk, S.; Hinton, J.A.; Puehlhofer, G.; Aharonian, F.A.; Hofmann, W.; Reimer, O.; Wagner, S.

    2007-03-05

    We present X-ray observations of the as of yet unidentified very high-energy (VHE) {gamma}-ray source HESS J1640-465 with the aim of establishing a counterpart of this source in the keV energy range, and identifying the mechanism responsible for the VHE emission. The 21.8 ksec XMM-Newton observation of HESS J1640-465 in September 2005 represents a significant improvement in sensitivity and angular resolution over previous ASCA studies in this region. These new data show a hard-spectrum X-ray emitting object at the centroid of the H.E.S.S. source, within the shell of the radio Supernova Remnant (SNR) G338.3-0.0. This object is consistent with the position and flux previously measured by both ASCA and Swift-XRT but is now shown to be significantly extended. We argue that this object is very likely the counterpart to HESS J1640-465 and that both objects may represent the Pulsar Wind Nebula of an as of yet undiscovered pulsar associated with G338.3-0.0.

  1. Discovery of the near-infrared counterpart to the luminous neutron-star low-mass X-ray binary GX 3+1

    Energy Technology Data Exchange (ETDEWEB)

    Van den Berg, Maureen; Fridriksson, Joel K. [Anton Pannekoek Institute for Astronomy, University of Amsterdam, Science Park 904, 1098 XH Amsterdam (Netherlands); Homan, Jeroen [Massachusetts Institute of Technology, Kavli Institute for Astrophysics and Space Research, 70 Vassar Street, Cambridge, MA 02139 (United States); Linares, Manuel, E-mail: M.C.vandenBerg@uva.nl [Instituto de Astrofísica de Canarias (IAC), Vía Láctea s/n, La Laguna, E-38205, S/C de Tenerife (Spain)

    2014-10-01

    Using the High Resolution Camera on board the Chandra X-ray Observatory, we have measured an accurate position for the bright persistent neutron star X-ray binary and atoll source GX 3+1. At a location that is consistent with this new position, we have discovered the near-infrared (NIR) counterpart to GX 3+1 in images taken with the PANIC and FourStar cameras on the Magellan Baade Telescope. The identification of this K{sub s} = 15.8 ± 0.1 mag star as the counterpart is based on the presence of a Br γ emission line in an NIR spectrum taken with the Folded-port InfraRed Echelette spectrograph on the Baade Telescope. The absolute magnitude derived from the best available distance estimate to GX 3+1 indicates that the mass donor in the system is not a late-type giant. We find that the NIR light in GX 3+1 is likely dominated by the contribution from a heated outer accretion disk. This is similar to what has been found for the NIR flux from the brighter class of Z sources, but unlike the behavior of atolls fainter (L{sub X} ≈ 10{sup 36}-10{sup 37} erg s{sup –1}) than GX 3+1, where optically thin synchrotron emission from a jet probably dominates the NIR flux.

  2. Strategies for Prompt Searches for GRB Afterglows: The Discovery of GRB 001011 Optical/Near-Infrared Counterpart Using Colour-Colour Selection

    Science.gov (United States)

    Gorosabel, J.; Fynbo, J. U.; Hjorth, J.; Wolf, C.; Andersen, M. I.; Pedersen, H.; Christensen, L.; Jensen, B. L.; Moller, P.; Afonso, J.; hide

    2001-01-01

    We report the discovery of the optical and near-infrared counterpart to GRB 001011. The GRB 001011 error box determined by Beppo-SAX was simultaneously imaged in the near-infrared by the 3.58-m. New Technology Telescope and in the optical by the 1.54-m Danish Telescope - 8 hr after the gamma-ray event. We implement the colour-colour discrimination technique proposed by Rhoads (2001) and extend it using near-IR data as well. We present the results provided by an automatic colour-colour discrimination pipe-line developed to discern the different populations of objects present in the GRB 001011 error box. Our software revealed three candidates based on single-epoch images. Second-epoch observations carried out approx. 3.2 days after the burst revealed that the most likely candidate had faded thus identifying it with the counterpart to the GRB. In deep R-band images obtained 7 months after the burst a faint (R=25.38 plus or minus 0.25) elongated object, presumably the host galaxy of GRB 001011, was detected at the position of the afterglow. The GRB 001011 afterglow is the first discovered with the assistance of colour-colour diagram techniques. We discuss the advantages of using this method and its application to boxes determined by future missions.

  3. Mental wellbeing amongst younger and older migrant workers in comparison to their urban counterparts in Guangzhou city, China: a cross-sectional study.

    Science.gov (United States)

    Li, Jie; Chang, Shu-Sen; Yip, Paul S F; Li, Juan; Jordan, Lucy P; Tang, Yunge; Hao, Yuantao; Huang, Xingmei; Yang, Ning; Chen, Chaoqi; Zeng, Qiaomei

    2014-12-16

    There has been a dramatic increase in internal migrant workers in China over recent decades, and there is a recent concern of poor mental health particularly amongst younger or "new generation" migrants who were born in 1980 or later. A cross-sectional study was conducted in Guangzhou city between May and July in 2012. Mental wellbeing was measured using the World Health Organization Five-item Well-Being Index Scale and the 36 Item Short Form Health Survey mental health scale. Linear and logistic regression models were used to investigate the differences between migrant workers and their urban counterparts and between younger and older migrants. Migrant workers (n = 914) showed a small but significant advantage in mental wellbeing compared to their urban counterparts (n = 814). There was some evidence for age modification effect (p for interaction = 0.055-0.095); better mental wellbeing in migrants than urbanites were mainly seen in the older compared to the younger group, and the difference attenuated somewhat after controlling for income satisfaction. Older migrants showed better mental health than younger migrants. Factors that were independently associated with poor mental health in migrants included being male, longer working hours, and income dissatisfaction, whilst older age, factory job, high income, and increased use of social support resources were associated with reduced risk. Efforts to promote mental health amongst migrant workers may be usefully targeted on younger migrants and include measures aimed to improve working conditions, strengthen the social support network, and address age-specific needs.

  4. Functional analysis, spectral theory, and applications

    CERN Document Server

    Einsiedler, Manfred

    2017-01-01

    This textbook provides a careful treatment of functional analysis and some of its applications in analysis, number theory, and ergodic theory. In addition to discussing core material in functional analysis, the authors cover more recent and advanced topics, including Weyl’s law for eigenfunctions of the Laplace operator, amenability and property (T), the measurable functional calculus, spectral theory for unbounded operators, and an account of Tao’s approach to the prime number theorem using Banach algebras. The book further contains numerous examples and exercises, making it suitable for both lecture courses and self-study. Functional Analysis, Spectral Theory, and Applications is aimed at postgraduate and advanced undergraduate students with some background in analysis and algebra, but will also appeal to everyone with an interest in seeing how functional analysis can be applied to other parts of mathematics.

  5. Intelligent multi-spectral IR image segmentation

    Science.gov (United States)

    Lu, Thomas; Luong, Andrew; Heim, Stephen; Patel, Maharshi; Chen, Kang; Chao, Tien-Hsin; Chow, Edward; Torres, Gilbert

    2017-05-01

    This article presents a neural network based multi-spectral image segmentation method. A neural network is trained on the selected features of both the objects and background in the longwave (LW) Infrared (IR) images. Multiple iterations of training are performed until the accuracy of the segmentation reaches satisfactory level. The segmentation boundary of the LW image is used to segment the midwave (MW) and shortwave (SW) IR images. A second neural network detects the local discontinuities and refines the accuracy of the local boundaries. This article compares the neural network based segmentation method to the Wavelet-threshold and Grab-Cut methods. Test results have shown increased accuracy and robustness of this segmentation scheme for multi-spectral IR images.

  6. Spectral functions from anisotropic lattice QCD

    Science.gov (United States)

    Aarts, G.; Allton, C.; Amato, A.; Evans, W.; Giudice, P.; Harris, T.; Kelly, A.; Kim, S. Y.; Lombardo, M. P.; Praki, K.; Ryan, S. M.; Skullerud, J.-I.

    2016-12-01

    The FASTSUM collaboration has been carrying out lattice simulations of QCD for temperatures ranging from one third to twice the crossover temperature, investigating the transition region, as well as the properties of the Quark Gluon Plasma. In this contribution we concentrate on quarkonium correlators and spectral functions. We work in a fixed scale scheme and use anisotropic lattices which help achieving the desirable fine resolution in the temporal direction, thus facilitating the (ill posed) integral transform from imaginary time to frequency space. We contrast and compare results for the correlators obtained with different methods, and different temporal spacings. We observe robust features of the results, confirming the sequential dissociation scenario, but also quantitative differences indicating that the methods' systematic errors are not yet under full control. We briefly outline future steps towards accurate results for the spectral functions and their associated statistical and systematic errors.

  7. Spectral emissivity of surface blackbody calibrators

    DEFF Research Database (Denmark)

    Clausen, Sønnik

    2007-01-01

    in emissivity using similar materials can be reduced to 0.5-1% by optimizing the coating process and the surface geometry. Results are discussed and an equation for calculation of the equivalent blackbody surface temperature from FTIR spectra is presented, including reflected ambient radiation. It is in most......The normal spectral emissivity of commercial infrared calibrators is compared with measurements of anodized aluminum samples and grooved aluminum surfaces coated with Pyromark. Measurements performed by FTIR spectroscopy in the wavelength interval from 2 to 20 mu m and at temperatures between 5...... and 550 degrees C are presented with absolute uncertainties from 0.25% to 1% in spectral regions with sufficient signal and no significant atmospheric gas absorption. A large variation in emissivity with wavelength is observed for some surfaces, i.e., from 1% to 3% to more than 10%. The variation...

  8. Decimative Spectral Estimation with Unconstrained Model Order

    Directory of Open Access Journals (Sweden)

    Stavroula-Evita Fotinea

    2012-01-01

    Full Text Available This paper presents a new state-space method for spectral estimation that performs decimation by any factor, it makes use of the full set of data and brings further apart the poles under consideration, while imposing almost no constraints to the size of the Hankel matrix (model order, as decimation increases. It is compared against two previously proposed techniques for spectral estimation (along with derived decimative versions, that lie among the most promising methods in the field of spectroscopy, where accuracy of parameter estimation is of utmost importance. Moreover, it is compared against a state-of-the-art purely decimative method proposed in literature. Experiments performed on simulated NMR signals prove the new method to be more robust, especially for low signal-to-noise ratio.

  9. Quantum Probability and Spectral Analysis of Graphs

    CERN Document Server

    Hora, Akihito

    2007-01-01

    This is the first book to comprehensively cover the quantum probabilistic approach to spectral analysis of graphs. This approach has been developed by the authors and has become an interesting research area in applied mathematics and physics. The book can be used as a concise introduction to quantum probability from an algebraic aspect. Here readers will learn several powerful methods and techniques of wide applicability, which have been recently developed under the name of quantum probability. The exercises at the end of each chapter help to deepen understanding. Among the topics discussed along the way are: quantum probability and orthogonal polynomials; asymptotic spectral theory (quantum central limit theorems) for adjacency matrices; the method of quantum decomposition; notions of independence and structure of graphs; and asymptotic representation theory of the symmetric groups.

  10. Spectral signature selection for mapping unvegetated soils

    Science.gov (United States)

    May, G. A.; Petersen, G. W.

    1975-01-01

    Airborne multispectral scanner data covering the wavelength interval from 0.40-2.60 microns were collected at an altitude of 1000 m above the terrain in southeastern Pennsylvania. Uniform training areas were selected within three sites from this flightline. Soil samples were collected from each site and a procedure developed to allow assignment of scan line and element number from the multispectral scanner data to each sampling location. These soil samples were analyzed on a spectrophotometer and laboratory spectral signatures were derived. After correcting for solar radiation and atmospheric attenuation, the laboratory signatures were compared to the spectral signatures derived from these same soils using multispectral scanner data. Both signatures were used in supervised and unsupervised classification routines. Computer-generated maps using the laboratory and multispectral scanner derived signatures resulted in maps that were similar to maps resulting from field surveys. Approximately 90% agreement was obtained between classification maps produced using multispectral scanner derived signatures and laboratory derived signatures.

  11. Stochastic Spectral and Conjugate Descent Methods

    KAUST Repository

    Kovalev, Dmitry

    2018-02-11

    The state-of-the-art methods for solving optimization problems in big dimensions are variants of randomized coordinate descent (RCD). In this paper we introduce a fundamentally new type of acceleration strategy for RCD based on the augmentation of the set of coordinate directions by a few spectral or conjugate directions. As we increase the number of extra directions to be sampled from, the rate of the method improves, and interpolates between the linear rate of RCD and a linear rate independent of the condition number. We develop and analyze also inexact variants of these methods where the spectral and conjugate directions are allowed to be approximate only. We motivate the above development by proving several negative results which highlight the limitations of RCD with importance sampling.

  12. Luminosity and spectral evolution of QSOs

    CERN Document Server

    Choi, Y Y; Yi, I S

    1999-01-01

    We apply the observed spectral states of the Galactic black hole candidates (GBHCs) to the quasi-stellar object (QSO) luminosity evolution based on the correlation between luminosity and the spectrum, which is strongly supported by the similarities of emission mechanisms in GBHCs and QSOs. We derive the QSO luminosity evolution trends in the UV/optical and the X-ray energy bands and demonstrate that their trends are significantly affected by the spectral evolution. Each energy band shows distinct evolution properties. We test one of the widely discussed cosmological evolution scenarios of QSOs, in which QSOs evolve as a single long-lived population, and show that the resulting luminosity functions seen in different energy bands exhibit distinguishable and potentially observable evolution signatures in the X-ray energy bands.

  13. On Spectral Triples in Quantum Gravity I

    DEFF Research Database (Denmark)

    Aastrup, Johannes; M. Grimstrup, Jesper; Nest, Ryszard

    2009-01-01

    This paper establishes a link between Noncommutative Geometry and canonical quantum gravity. A semi-finite spectral triple over a space of connections is presented. The triple involves an algebra of holonomy loops and a Dirac type operator which resembles a global functional derivation operator....... The interaction between the Dirac operator and the algebra reproduces the Poisson structure of General Relativity. Moreover, the associated Hilbert space corresponds, up to a discrete symmetry group, to the Hilbert space of diffeomorphism invariant states known from Loop Quantum Gravity. Correspondingly......, the square of the Dirac operator has, in terms of canonical quantum gravity, the form of a global area-squared operator. Furthermore, the spectral action resembles a partition function of Quantum Gravity. The construction is background independent and is based on an inductive system of triangulations...

  14. Multifrequency electrical impedance tomography using spectral constraints.

    Science.gov (United States)

    Malone, Emma; Sato Dos Santos, Gustavo; Holder, David; Arridge, Simon

    2014-02-01

    Multifrequency electrical impedance tomography (MFEIT) exploits the dependence of tissue impedance on frequency to recover an image of conductivity. MFEIT could provide emergency diagnosis of pathologies such as acute stroke, brain injury and breast cancer. We present a method for performing MFEIT using spectral constraints. Boundary voltage data is employed directly to reconstruct the volume fraction distribution of component tissues using a nonlinear method. Given that the reconstructed parameter is frequency independent, this approach allows for the simultaneous use of all multifrequency data, thus reducing the degrees of freedom of the reconstruction problem. Furthermore, this method allows for the use of frequency difference data in a nonlinear reconstruction algorithm. Results from empirical phantom measurements suggest that our fraction reconstruction method points to a new direction for the development of multifrequency EIT algorithms in the case that the spectral constraints are known, and may provide a unifying framework for static EIT imaging.

  15. Nonparametric Collective Spectral Density Estimation and Clustering

    KAUST Repository

    Maadooliat, Mehdi

    2017-04-12

    In this paper, we develop a method for the simultaneous estimation of spectral density functions (SDFs) for a collection of stationary time series that share some common features. Due to the similarities among the SDFs, the log-SDF can be represented using a common set of basis functions. The basis shared by the collection of the log-SDFs is estimated as a low-dimensional manifold of a large space spanned by a pre-specified rich basis. A collective estimation approach pools information and borrows strength across the SDFs to achieve better estimation efficiency. Also, each estimated spectral density has a concise representation using the coefficients of the basis expansion, and these coefficients can be used for visualization, clustering, and classification purposes. The Whittle pseudo-maximum likelihood approach is used to fit the model and an alternating blockwise Newton-type algorithm is developed for the computation. A web-based shiny App found at

  16. Spectral theory and nonlinear functional analysis

    CERN Document Server

    Lopez-Gomez, Julian

    2001-01-01

    This Research Note addresses several pivotal problems in spectral theory and nonlinear functional analysis in connection with the analysis of the structure of the set of zeroes of a general class of nonlinear operators. It features the construction of an optimal algebraic/analytic invariant for calculating the Leray-Schauder degree, new methods for solving nonlinear equations in Banach spaces, and general properties of components of solutions sets presented with minimal use of topological tools. The author also gives several applications of the abstract theory to reaction diffusion equations and systems.The results presented cover a thirty-year period and include recent, unpublished findings of the author and his coworkers. Appealing to a broad audience, Spectral Theory and Nonlinear Functional Analysis contains many important contributions to linear algebra, linear and nonlinear functional analysis, and topology and opens the door for further advances.

  17. Spectral Networks and Fenchel-Nielsen Coordinates

    Science.gov (United States)

    Hollands, Lotte; Neitzke, Andrew

    2016-06-01

    It is known that spectral networks naturally induce certain coordinate systems on moduli spaces of flat SL( K)-connections on surfaces, previously studied by Fock and Goncharov. We give a self-contained account of this story in the case K = 2 and explain how it can be extended to incorporate the complexified Fenchel-Nielsen coordinates. As we review, the key ingredient in the story is a procedure for passing between moduli of flat SL(2)-connections on C (equipped with a little extra structure) and moduli of equivariant GL(1)-connections over a covering {Σ to C}; taking holonomies of the equivariant GL(1)-connections then gives the desired coordinate systems on moduli of SL(2)-connections. There are two special types of spectral network, related to ideal triangulations and pants decompositions of C; these two types of network lead to Fock-Goncharov and complexified Fenchel-Nielsen coordinate systems, respectively.

  18. Flatfield correction errors due to spectral mismatching

    Science.gov (United States)

    Hagen, Nathan

    2014-12-01

    Flat field calibration of broadband imaging systems is widely used, and it has been said that users should try to make the spectrum of the flatfield calibration light source as close as possible to that of the measurement object. However, a quantitative analysis of the error induced by a mismatch of calibration and object spectra has been lacking. In order to develop this quantitative analysis, we provide a theoretical radiometric model for flatfield calibration and show how this spectral mismatching error arises. Simulations covering a variety of measurement scenarios indicate that spectral mismatching can create quantitative errors of up to a factor of 5 in situations that are regularly encountered by researchers performing quantitative work.

  19. Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) II: Spectral Homogeneity Among Hungaria Family Asteroids

    Science.gov (United States)

    Lucas, Michael P.; Emery, Joshua; Pinilla-Alonso, Noemi; Lindsay, Sean S.; MacLennan, Eric M.; Cartwright, Richard; Reddy, Vishnu; Sanchez, Juan A.; Thomas, Cristina A.; Lorenzi, Vania

    2017-10-01

    Spectral observations of asteroid family members provide valuable information regarding parent body interiors, the source regions of near-Earth asteroids, and the link between meteorites and their parent bodies. Hungaria family asteroids constitute the closest samples to the Earth from a collisional family (~1.94 AU), permitting observations of smaller fragments than accessible for Main Belt families. We have carried out a ground-based observational campaign - Hungaria Asteroid Region Telescopic Spectral Survey (HARTSS) - to record reflectance spectra of these preserved samples from the inner-most primordial asteroid belt. During HARTSS phase one (Lucas et al. [2017]. Icarus 291, 268-287) we found that ~80% of the background population is comprised of stony S-complex asteroids that exhibit considerable spectral and mineralogical diversity. In HARTSS phase two, we turn our attention to family members and hypothesize that the Hungaria collisional family is homogeneous. We test this hypothesis through taxonomic classification, albedo estimates, and spectral properties.During phase two of HARTSS we acquired near-infrared (NIR) spectra of 50 new Hungarias (19 family; 31 background) with SpeX/IRTF and NICS/TNG. We analyzed X-type family spectra for NIR color indices (0.85-J J-K), and a subtle ~0.9 µm absorption feature that may be attributed to Fe-poor orthopyroxene. Surviving fragments of an asteroid collisional family typically exhibit similar taxonomies, albedos, and spectral properties. Spectral analysis of X-type Hungaria family members and independently calculated WISE albedo determinations for 428 Hungaria asteroids is consistent with this scenario. Furthermore, ~1/4 of the background population exhibit similar spectral properties and albedos to family X-types.Spectral observations of 92 Hungaria region asteroids acquired during both phases of HARTSS uncover a compositionally heterogeneous background and spectral homogeneity down to ~2 km for collisional family

  20. Artifacts Of Spectral Analysis Of Instrument Readings

    Science.gov (United States)

    Wise, James H.

    1995-01-01

    Report presents experimental and theoretical study of some of artifacts introduced by processing outputs of two nominally identical low-frequency-reading instruments; high-sensitivity servo-accelerometers mounted together and operating, in conjunction with signal-conditioning circuits, as seismometers. Processing involved analog-to-digital conversion with anti-aliasing filtering, followed by digital processing including frequency weighting and computation of different measures of power spectral density (PSD).

  1. SURFACE ALBEDO AND SPECTRAL VARIABILITY OF CERES

    Energy Technology Data Exchange (ETDEWEB)

    Li, Jian-Yang; Reddy, Vishnu; Corre, Lucille Le; Sykes, Mark V.; Prettyman, Thomas H. [Planetary Science Institute, 1700 E. Ft. Lowell Road, Suite 106, Tucson, AZ 85719 (United States); Nathues, Andreas; Hoffmann, Martin; Schaefer, Michael [Max Planck Institute for Solar System Research, Göttingen (Germany); Izawa, Matthew R. M.; Cloutis, Edward A. [University of Winnipeg, Winnipeg, Manitoba (Canada); Carsenty, Uri; Jaumann, Ralf; Krohn, Katrin; Mottola, Stefano; Schröder, Stefan E. [German Aerospace Center (DLR), Institute of Planetary Research, Berlin (Germany); Castillo-Rogez, Julie C. [Jet Propulsion Laboratory, California Institute of Technology, Pasadena, CA 91109 (United States); Schenk, Paul [Lunar and Planetary Institute, Houston, TX 77058 (United States); Williams, David A. [School of Earth and Space Exploration, Arizona State University, Tempe, AZ 85287 (United States); Smith, David E. [Solar System Exploration Division, NASA Goddard Space Flight Center, Greenbelt, MD 20771 (United States); Zuber, Maria T. [Department of Earth, Atmospheric and Planetary Sciences, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); and others

    2016-02-01

    Previous observations suggested that Ceres has active, but possibly sporadic, water outgassing as well as possibly varying spectral characteristics over a timescale of months. We used all available data of Ceres collected in the past three decades from the ground and the Hubble Space Telescope, as well as the newly acquired images by the Dawn  Framing Camera, to search for spectral and albedo variability on Ceres, on both a global scale and in local regions, particularly the bright spots inside the Occator crater, over timescales of a few months to decades. Our analysis has placed an upper limit on the possible temporal albedo variation on Ceres. Sporadic water vapor venting, or any possibly ongoing activity on Ceres, is not significant enough to change the albedo or the area of the bright features in the Occator crater by >15%, or the global albedo by >3% over the various timescales that we searched. Recently reported spectral slope variations can be explained by changing Sun–Ceres–Earth geometry. The active area on Ceres is less than 1 km{sup 2}, too small to cause global albedo and spectral variations detectable in our data. Impact ejecta due to impacting projectiles of tens of meters in size like those known to cause observable changes to the surface albedo on Asteroid Scheila cannot cause detectable albedo change on Ceres due to its relatively large size and strong gravity. The water vapor activity on Ceres is independent of Ceres’ heliocentric distance, ruling out the possibility of the comet-like sublimation process as a possible mechanism driving the activity.

  2. Evolutionary Computing Methods for Spectral Retrieval

    Science.gov (United States)

    Terrile, Richard; Fink, Wolfgang; Huntsberger, Terrance; Lee, Seugwon; Tisdale, Edwin; VonAllmen, Paul; Tinetti, Geivanna

    2009-01-01

    A methodology for processing spectral images to retrieve information on underlying physical, chemical, and/or biological phenomena is based on evolutionary and related computational methods implemented in software. In a typical case, the solution (the information that one seeks to retrieve) consists of parameters of a mathematical model that represents one or more of the phenomena of interest. The methodology was developed for the initial purpose of retrieving the desired information from spectral image data acquired by remote-sensing instruments aimed at planets (including the Earth). Examples of information desired in such applications include trace gas concentrations, temperature profiles, surface types, day/night fractions, cloud/aerosol fractions, seasons, and viewing angles. The methodology is also potentially useful for retrieving information on chemical and/or biological hazards in terrestrial settings. In this methodology, one utilizes an iterative process that minimizes a fitness function indicative of the degree of dissimilarity between observed and synthetic spectral and angular data. The evolutionary computing methods that lie at the heart of this process yield a population of solutions (sets of the desired parameters) within an accuracy represented by a fitness-function value specified by the user. The evolutionary computing methods (ECM) used in this methodology are Genetic Algorithms and Simulated Annealing, both of which are well-established optimization techniques and have also been described in previous NASA Tech Briefs articles. These are embedded in a conceptual framework, represented in the architecture of the implementing software, that enables automatic retrieval of spectral and angular data and analysis of the retrieved solutions for uniqueness.

  3. Spectral Element Multigrid. Part 2. Theoretical Justification

    Science.gov (United States)

    1988-12-01

    R.VERFORTH - A note on multigrid methods for nonconforming finite element methods, Stochastische Mathematische Modellenumber 453, Mars 1988. Preprint...submitted to SIAM J. Numer. Anal. [MM] J. F. MAITRE & F. MUSY - Multigrid methods : Convergence theory in a variational framework, SINUM 21, 4,(1984) pp...Equations-M, SIAM (1984). [ZWHl] T.A. ZANG, Y. S. WONG & M.Y. HUSSAINI - Spectral multigrid methods for elliptic equations, J.CP. 49,(1982) pp485-50l

  4. Theory of atomic spectral emission intensity

    International Nuclear Information System (INIS)

    Yngstroem, S.

    1989-02-01

    The theoretical derivation of a new spectral line intensity formula for atomic radiative emission is presented. The theory is based on first principles of quantum physics and statistical physics. It is argued that the formulation of the theory provides a very good example of the manner in which quantum logic transforms into common sense logic. The theory is strongly supported by experimental evidence. (author) (16 refs.)

  5. Advanced Spectral Library (ASTRAL): Cool stars edition

    Science.gov (United States)

    Ayres, T. R.

    2013-02-01

    ASTRAL is a project to create high-resolution, high-S/N UV (1150-3200 Å) atlases of bright stars utilizing {HST}/STIS. During Cycle 18 (2010-2011), eight cool star targets were observed, including key objects like Procyon and Betelgeuse, churning through 146 orbits in the process. The new spectral atlases are publically available through the project website. Data were obtained with the Hubble Space Telescope.

  6. A spectral route to determining chirality

    DEFF Research Database (Denmark)

    Pedersen, Jesper Goor; Mortensen, Asger

    2009-01-01

    We show how one-dimensional structured media can be used to measure chirality, via the spectral shift of the photonic band gap edges. Analytically, we show that a chiral contrast can, in some cases, be mapped unto an index contrast, thereby greatly simplifying the analysis of such structures. Using...... this mapping, we derive a first-order shift of the band gap edges with chirality. Potentially, this effect could be used for measuring enantiomeric excess....

  7. Spectral converters and luminescent solar concentrators

    Energy Technology Data Exchange (ETDEWEB)

    Scudo, Petra F.; Abbondanza, Luigi; Fusco, Roberto; Caccianotti, Luciano [Eni S.p.A, Research Center for Non-Conventional Energies - Istituto ENI Donegani, Via G.Fauser 4, 28100 Novara (Italy)

    2010-07-15

    In this paper we present a comprehensive theoretical description of molecular spectral converters in the specific context of luminescent solar concentrators (LSCs). The theoretical model is an extension to a three-level system interacting with a solar radiation bath of the standard quantum theory of atomic radiative processes. We derive the equilibrium equations of the conversion process and provide specific examples of application of this principle to the development of solar concentration devices. (author)

  8. Temporal and spectral interaction in loudness perception

    DEFF Research Database (Denmark)

    Pedersen, Benjamin; Ellermeier, Wolfgang

    An experiment was conducted to investigate how changes in spectral content influence loudness judgments. Six listeners were asked to discriminate sounds, which were of one second duration and changing in level every 0.1 s. In one condition the first half of the sound was low-pass filtered and the....... This outcome is inconsistent with overall temporal integration, and argues for a cognitive mechanism allocating attention to changes in an event sequence....

  9. Spectrally efficient polymer optical fiber transmission

    Science.gov (United States)

    Randel, Sebastian; Bunge, Christian-Alexander

    2011-01-01

    The step-index polymer optical fiber (SI-POF) is an attractive transmission medium for high speed communication links in automotive infotainment networks, in industrial automation, and in home networks. Growing demands for quality of service, e.g., for IPTV distribution in homes and for Ethernet based industrial control networks will necessitate Gigabit speeds in the near future. We present an overview on recent advances in the design of spectrally efficient and robust Gigabit-over-SI-POF transmission systems.

  10. New Spectral Features from Bound Dark Matter

    DEFF Research Database (Denmark)

    Catena, Riccardo; Kouvaris, Chris

    2016-01-01

    We demonstrate that dark matter particles gravitationally bound to the Earth can induce a characteristic nuclear recoil signal at low energies in direct detection experiments. The new spectral feature we predict can provide the ultimate smoking gun for dark matter discovery for experiments...... with positive signal but unclear background. The new feature is universal, in that the ratio of bound over halo dark matter event rates at detectors is independent of the dark matter-nucleon cross section....

  11. Non-Redundant Spectral Dimensionality Reduction

    OpenAIRE

    Blau, Yochai; Michaeli, Tomer

    2016-01-01

    Spectral dimensionality reduction algorithms are widely used in numerous domains, including for recognition, segmentation, tracking and visualization. However, despite their popularity, these algorithms suffer from a major limitation known as the "repeated Eigen-directions" phenomenon. That is, many of the embedding coordinates they produce typically capture the same direction along the data manifold. This leads to redundant and inefficient representations that do not reveal the true intrinsi...

  12. Multiple Kernel Spectral Regression for Dimensionality Reduction

    OpenAIRE

    Liu, Bing; Xia, Shixiong; Zhou, Yong

    2013-01-01

    Traditional manifold learning algorithms, such as locally linear embedding, Isomap, and Laplacian eigenmap, only provide the embedding results of the training samples. To solve the out-of-sample extension problem, spectral regression (SR) solves the problem of learning an embedding function by establishing a regression framework, which can avoid eigen-decomposition of dense matrices. Motivated by the effectiveness of SR, we incorporate multiple kernel learning (MKL) into SR for dimensionality...

  13. Spectral analysis of blood flow in rat

    International Nuclear Information System (INIS)

    Arnautovic, M.; Jerkic, M.; Gal, V.

    1997-01-01

    Blood flow was continuously monitored in carotid, femoral and renal arteries in rats with acute renal failure and in the animals of control group. The spectral analysis of data were done using fast Fourier transform. Two characteristic peaks were obtained. The dominant component has frequency corresponding to heart rate, (4-7)Hz, while the frequency of the other peak is about 1 Hz. A physiological interpretation of the data is presented. (author)

  14. Power Spectral Density and Hilbert Transform

    Science.gov (United States)

    2016-12-01

    2002. Pierce J. An introduction to information theory : symbols, signals , and noise. New York (NY): Dover Publications; 1980. Soumekh M. Fourier array...NOTES 14. ABSTRACT This technical report focuses on the Hilbert transform and some of its applications for digital signal processing. Herein we...review power spectral density and complex exponentials, and illustrate how the Hilbert transform converts a real signal (real in the sense of a real time

  15. Canopy spectral invariants for remote sensing and model applications

    NARCIS (Netherlands)

    Huang, D.; Knyazikhin, Y.; Dickinson, R.E.; Rautiainen, M.; Stenberg, P.; Disney, M.; Lewis, P.; Cescatti, A.; Tian, Y.; Verhoef, W.; Martonchik, J.V.; Myneni, R.B.

    2007-01-01

    The concept of canopy spectral invariants expresses the observation that simple algebraic combinations of leaf and canopy spectral transmittance and reflectance become wavelength independent and determine a small set of canopy structure specific variables. This set includes the canopy interceptance,

  16. Spectral entropy and haemodynamic response to surgery during ...

    African Journals Online (AJOL)

    Adele

    Spectral entropy and haemodynamic response to surgery during sevoflurane anaesthesia. Introduction. Apart from somatic responses, surgery also evokes autonomic responses, including haemodynamic responses. Spectral entropy has been validated as a means to monitor the hypnotic state during sevoflurane ...

  17. COFFEE - Coherent Optical System Field Trial for Spectral Efficiency Enhancement

    DEFF Research Database (Denmark)

    Imran, Muhammad; Fresi, Francesco; Rommel, Simon

    2016-01-01

    The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented.......The scope, aims, and contributions of the COFFEE project for spectral efficiency enhancement and market exposure are presented....

  18. Spectral factorization using the delta operator

    DEFF Research Database (Denmark)

    Rostgaard, Morten; Poulsen, Niels Kjølstad; Ravn, Ole

    1994-01-01

    In recent years many papers have been published abouth the gamma-operator, mostly caused by the better numerical properties and the rapprochement between continuous and discrete time. A major problem within the LQG-design of a delta-based input-output relation has been how to spectral-factorize i......In recent years many papers have been published abouth the gamma-operator, mostly caused by the better numerical properties and the rapprochement between continuous and discrete time. A major problem within the LQG-design of a delta-based input-output relation has been how to spectral......-factorize in an efficient way. The discrete-time method of Kuccera will not be applied since numerical word-length characteristics will be poor for fast sampling rates. In this paper a new approach is considered. A new gamma-operator (Tustin operator) is introduced, in order to make an iterative and numerical stable...... solution to the spectral factorization problem. The key idea is to use the gamma-operator resembled by its behavior to the differential operator....

  19. A spectral algorithm for the seriation problem

    Energy Technology Data Exchange (ETDEWEB)

    Atkins, J.E. [Michigan Univ., Ann Arbor, MI (United States). Dept. of Mathematics; Boman, E.G. [Stanford Univ., CA (United States). Dept. of Computer Science; Hendrickson, B. [Sandia National Labs., Albuquerque, NM (United States)

    1994-11-01

    Given a set of objects and a correlation function f reflecting the desire for two items to be near each other, find all sequences {pi} of the items so that correlation preferences are preserved; that is if {pi}(i) < {pi}(j) < {pi}(k) then f(i,j) {ge} f(i,k) and f(j,k) {ge} f(i,k). This seriation problem has numerous applications, for instance, solving it yields a solution to the consecutive ones problem. We present a spectral algorithm for this problem that has a number of interesting features. Whereas most previous applications of spectral techniques provided bounds or heuristics, our result is an algorithm for a nontrivial combinatorial problem. Our analysis introduces powerful tools from matrix theory to the theoretical computer science community. Also, spectral methods are being applied as heuristics for a variety of sequencing problems and our result helps explain and justify these applications. Although the worst case running time for our approach is not competitive with that of existing methods for well posed problem instances, unlike combinatorial approaches our algorithm remains a credible heuristic for the important cases where there are errors in the data.

  20. The Advanced Spectral Library (ASTRAL) Project

    Science.gov (United States)

    Ayres, Thomas R.; The ASTRAL I & Science Teams, II

    2014-01-01

    The Advanced Spectral Library (ASTRAL) is an HST Treasury Program whose aim is to secure definitive ultraviolet (115-310 nm) spectra of representative bright stars utilizing the venerable -- yet still state-of-the-art -- Space Telescope Imaging Spectrograph (STIS). The initial Cycle 18 installment of the program (146 orbits in 2010-2011) focused on late-type (``cool’’) stars, acquiring high-S/N, high spectral resolution measurements of eight pivotal targets, including iconic objects like Betelgeuse and Procyon. The latest episode, in current Cycle 21 (230 orbits in 2013-2014), is designed to record very high-S/N (>100) STIS echellegrams, at the highest resolution feasible ( 30,000-100,000), of 21 representative bright early-type (``hot’’) stars, including equally iconic objects like Vega, Sirius, Regulus, and Zeta Puppis. The targets span a broad range of spectral types between early-O and early-A, encompassing main sequence and evolved stars, fast and slow rotators, as well as chemically peculiar and magnetic objects. These high-quality STIS UV spectra will be publicly available immediately after observation from the HST archive; and, in post-processed and merged form, at the project website: http://casa.colorado.edu ayres/ASTRAL/. The UV "atlases" produced by the ASTRAL Program will enable investigations of a broad range of astrophysical problems -- stellar, interstellar, and beyond -- for many years to come. Supported by Guest Observer grants from STScI.

  1. The spectral imaging facility: Setup characterization

    Energy Technology Data Exchange (ETDEWEB)

    De Angelis, Simone, E-mail: simone.deangelis@iaps.inaf.it; De Sanctis, Maria Cristina; Manzari, Paola Olga [Institute for Space Astrophysics and Planetology, INAF-IAPS, Via Fosso del Cavaliere, 100, 00133 Rome (Italy); Ammannito, Eleonora [Institute for Space Astrophysics and Planetology, INAF-IAPS, Via Fosso del Cavaliere, 100, 00133 Rome (Italy); Department of Earth, Planetary and Space Sciences, University of California, Los Angeles, Los Angeles, California 90095-1567 (United States); Di Iorio, Tatiana [ENEA, UTMEA-TER, Rome (Italy); Liberati, Fabrizio [Opto Service SrL, Campagnano di Roma (RM) (Italy); Tarchi, Fabio; Dami, Michele; Olivieri, Monica; Pompei, Carlo [Selex ES, Campi Bisenzio (Italy); Mugnuolo, Raffaele [Italian Space Agency, ASI, Spatial Geodesy Center, Matera (Italy)

    2015-09-15

    The SPectral IMager (SPIM) facility is a laboratory visible infrared spectrometer developed to support space borne observations of rocky bodies of the solar system. Currently, this laboratory setup is used to support the DAWN mission, which is in its journey towards the asteroid 1-Ceres, and to support the 2018 Exo-Mars mission in the spectral investigation of the Martian subsurface. The main part of this setup is an imaging spectrometer that is a spare of the DAWN visible infrared spectrometer. The spectrometer has been assembled and calibrated at Selex ES and then installed in the facility developed at the INAF-IAPS laboratory in Rome. The goal of SPIM is to collect data to build spectral libraries for the interpretation of the space borne and in situ hyperspectral measurements of planetary materials. Given its very high spatial resolution combined with the imaging capability, this instrument can also help in the detailed study of minerals and rocks. In this paper, the instrument setup is first described, and then a series of test measurements, aimed to the characterization of the main subsystems, are reported. In particular, laboratory tests have been performed concerning (i) the radiation sources, (ii) the reference targets, and (iii) linearity of detector response; the instrumental imaging artifacts have also been investigated.

  2. Remote Sensing of Landscapes with Spectral Images

    Science.gov (United States)

    Adams, John B.; Gillespie, Alan R.

    2006-05-01

    Remote Sensing of Landscapes with Spectral Images describes how to process and interpret spectral images using physical models to bridge the gap between the engineering and theoretical sides of remote-sensing and the world that we encounter when we venture outdoors. The emphasis is on the practical use of images rather than on theory and mathematical derivations. Examples are drawn from a variety of landscapes and interpretations are tested against the reality seen on the ground. The reader is led through analysis of real images (using figures and explanations); the examples are chosen to illustrate important aspects of the analytic framework. This textbook will form a valuable reference for graduate students and professionals in a variety of disciplines including ecology, forestry, geology, geography, urban planning, archeology and civil engineering. It is supplemented by a web-site hosting digital color versions of figures in the book as well as ancillary images (www.cambridge.org/9780521662214). Presents a coherent view of practical remote sensing, leading from imaging and field work to the generation of useful thematic maps Explains how to apply physical models to help interpret spectral images Supplemented by a website hosting digital colour versions of figures in the book, as well as additional colour figures

  3. Asteroids: spectral reflectance and color characteristics. II

    International Nuclear Information System (INIS)

    McCord, T.B.; Chapman, C.R.

    1975-01-01

    We present new spectrophotometry for 31 asteroids, and improved data for nine previously observed, raising our total sample to 98. Several important new spectral types have been found. Asteroid 349 Dembowska is the first large main-belt asteroid found to resemble ordinary chondritic meteorites in spectral properties (it is similar to LL6 chondrites in pyroxene/olivine content). The first two measured Trojan asteroids show unusual spectra not compatible with carbonaceous chondrites or other known meteorites. The spectrum of Mars-crosser 887 Alinda is compatible with unequilibrated chondrites. Most fainter asteroids (especially those in the outer half of the belt) have flat spectra indicating probable carbonaceous composition. Compositional heterogeneity of Hirayama families is common among the 16 families studied to date. But individual asteroids seem to have remarkably uniform surface compositions, indicated by the usual lack of spectral changes with rotation. Spectra of a preliminary sample of proposed meteorite source-bodies are consistent with derivation of meteorites by proposed mechanics, but further observations are needed

  4. Estimating the Spectral Width of a Narrowband Optical Signal

    DEFF Research Database (Denmark)

    Lading, Lars; Skov Jensen, A.

    1980-01-01

    Methods for estimating the spectral width of a narrowband optical signal are investigated. Spectral analysis and Fourier spectroscopy are compared. Optimum and close-to-optimum estimators are developed under the constraint of having only one photodetector.......Methods for estimating the spectral width of a narrowband optical signal are investigated. Spectral analysis and Fourier spectroscopy are compared. Optimum and close-to-optimum estimators are developed under the constraint of having only one photodetector....

  5. Spectral beam combining of diode lasers with high efficiency

    DEFF Research Database (Denmark)

    Müller, André; Vijayakumar, Deepak; Jensen, Ole Bjarlin

    2012-01-01

    Based on spectral beam combining we obtain 16 W of output power, combining two 1063 nm DBR-tapered diode lasers. The spectral separation within the combined beam can be used for subsequent sum-frequency generation.......Based on spectral beam combining we obtain 16 W of output power, combining two 1063 nm DBR-tapered diode lasers. The spectral separation within the combined beam can be used for subsequent sum-frequency generation....

  6. SPECTRAL SETS AND TILES IN CARTESIAN PRODUCTS OVER ...

    Indian Academy of Sciences (India)

    41

    Spectral set conjecture: A Borel set Ω ⊂ Rd of positive and finite. Lebesgue measure is a spectral set if and only if it ... Ω ⊂ G of positive and finite Haar measure is a spectral set if and only if it is a translational tile. ... Key words and phrases. p-adic number field, Cartesian product, tile, spectral set. This work was supported by ...

  7. Spectral functions of a time-periodically driven Falicov-Kimball model: Real-space Floquet dynamical mean-field theory study

    Science.gov (United States)

    Qin, Tao; Hofstetter, Walter

    2017-08-01

    We present a systematic study of the spectral functions of a time-periodically driven Falicov-Kimball Hamiltonian. In the high-frequency limit, this system can be effectively described as a Harper-Hofstadter-Falicov-Kimball model. Using real-space Floquet dynamical mean-field theory (DMFT), we take into account the interaction effects and contributions from higher Floquet bands in a nonperturbative way. Our calculations show a high degree of similarity between the interacting driven system and its effective static counterpart with respect to spectral properties. However, as also illustrated by our results, one should bear in mind that Floquet DMFT describes a nonequilibrium steady state, while an effective static Hamiltonian describes an equilibrium state. We further demonstrate the possibility of using real-space Floquet DMFT to study edge states on a cylinder geometry.

  8. Stability estimates for hp spectral element methods for general ...

    Indian Academy of Sciences (India)

    Home; Journals; Proceedings – Mathematical Sciences; Volume 113; Issue 4. Stability Estimates for ℎ- Spectral ... We establish basic stability estimates for a non-conforming ℎ- spectral element method which allows for simultaneous mesh refinement and variable polynomial degree. The spectral element functions are ...

  9. Spectral control of diode lasers using external waveguide circuits

    NARCIS (Netherlands)

    Oldenbeuving, Ruud

    2013-01-01

    We investigated spectral control of diode lasers using external waveguide circuits. The purpose of this work is to investigate such external control for providing a new class of diode lasers with technologically interesting properties, such as a narrow spectral bandwidth and spectrally tunable

  10. Introduction to finite and spectral element methods using Matlab

    CERN Document Server

    Pozrikidis, Constantine

    2014-01-01

    The Finite Element Method in One Dimension. Further Applications in One Dimension. High-Order and Spectral Elements in One Dimension. The Finite Element Method in Two Dimensions. Quadratic and Spectral Elements in Two Dimensions. Applications in Mechanics. Viscous Flow. Finite and Spectral Element Methods in Three Dimensions. Appendices. References. Index.

  11. Relation of Core Dominance Parameter and Extended Spectral ...

    Indian Academy of Sciences (India)

    2016-01-27

    Jan 27, 2016 ... The correlations between differences of two core dominance parameters and core/extended spectral index are investigated. The extended spectral index is associated with the differences very well, while there is a weak relationship between core spectral index and the differences. The average core ...

  12. Application of combined temporal and spectral processing methods ...

    Indian Academy of Sciences (India)

    error (MMSE) short term spectral amplitude (STSA) estimators) first estimate the spectral characteristics .... band spectral subtraction (Kamath & Loizou 2002) or STSA–MMSE estimator (Ephraim &. Malah 1984) ...... Greenberg S, Kingsbury B E D 1997 The modulation spectrogram: in pursuit of an invariant repre- sentation of ...

  13. Relation of Core Dominance Parameter and Extended Spectral ...

    Indian Academy of Sciences (India)

    Relation of Core Dominance Parameter and Extended Spectral Index for Radio Sources. J. H. Yang1,2,∗, J. J. ... nance parameters and core/extended spectral index are investigated. The extended spectral index is ... (10JJ3020), and the research fund of Hunan University of Arts and Science (JJZD. 201101). References.

  14. Spectral Action for Torsion with and without Boundaries

    DEFF Research Database (Denmark)

    Iochum, B.; Levy, Cyril Olivier; Vassilevich, D.

    2012-01-01

    We derive a commutative spectral triple and study the spectral action for a rather general geometric setting which includes the (skew-symmetric) torsion and the chiral bag conditions on the boundary. The spectral action splits into bulk and boundary parts. In the bulk, we clarify certain issues...

  15. Spectral Information System for Australian Spectroscopy Data

    Science.gov (United States)

    Chisholm, L. A.; Ong, C.; Hueni, A.; Suarez, L.; Restrepo-Coupe, N.

    2013-12-01

    Inherently field spectroscopy involves the study of the interrelationships between the spectral characteristics of objects and their biophysical attributes in the field environment (Bauer et al., 1986; Milton, 1987). Spectroscopy measurements taken of vegetated surfaces provide spectral characteristics indicative of the status, composition and structure of the components measured. However, additional elements are present that add undesired effects to the overall signal such as the soil background or the viewing and illumination geometry (Suarez etal 2013). Further, the leaf spectrum is affected by several factors including leaf age, phenology, a highly variable range of stressors, any of which may be the actual focus of study, and additionally influenced by a range of environmental conditions. There is a critical need to use acquired spectra to infer vegetation function, understand phenological cycles, characterise biodiversity or as part of the process to assess biogeochemical processes. However the collection of leaf spectra during field campaigns is undertaken on a project basis, where a large number of spectra tend to be collected, yet the value and ability to share and confidently re-use such collections is often restricted. Often this is because the data are stored in disparate silos with little, if any, consistency in formatting and content, and most importantly, lack metadata to aid their discovery and re-use. These datasets have significant potential for vegetation scientists but also benefit the wider earth observation remote sensing and other earth science communities. In Australia this problem has been addressed by the adoption and enhancement of the existing SPECCHIO system (Hueni et al. 2009) as a suitable standard for spectral data exchange. As a spectral database, the system provides storage of spectra and associated metadata, retrieval of spectral data using metadata space queries, information on provenance, all of which facilitate repeatability of

  16. Recent Advances in Polymer Organic Light-Emitting Diodes (PLED) Using Non-conjugated Polymers as the Emitting Layer and Contrasting Them with Conjugated Counterparts

    Science.gov (United States)

    Wong, Michael Y.

    2017-11-01

    Polymer organic light-emitting diodes (PLED) are one of the most studied subjects in flexible electronics thanks to their economical wet fabrication procedure for enhanced price advantage of the product device. In order to optimize PLED efficiency, correlating the polymer structure with the device performance is essential. An important question for the researchers in this field is whether the polymer backbone is conjugated or not as it affects the device performance. In this review, recent advances in non-conjugated polymers employed as the emitting layer in PLED devices are first discussed, followed by their contrast with the conjugated counterparts in terms of polymer synthesis, sample quality, physical properties and device performances. Such comparison between conjugated and non-conjugated polymers for PLED applications is rarely attempted, and; hence, this review shall provide a useful insight of emitting polymers employed in PLEDs.

  17. Estimating detection rates for the LIGO-Virgo search for gravitational-wave burst counterparts to gamma-ray bursts using inferred local GRB rates

    International Nuclear Information System (INIS)

    Leonor, I; Frey, R; Sutton, P J; Jones, G; Marka, S; Marka, Z

    2009-01-01

    One of the ongoing searches performed using the LIGO-Virgo network of gravitational-wave interferometers is the search for gravitational-wave burst (GWB) counterparts to gamma-ray bursts (GRBs). This type of analysis makes use of GRB time and position information from gamma-ray satellite detectors to trigger the GWB search, and the GWB detection rates possible for such an analysis thus strongly depend on the GRB detection efficiencies of the satellite detectors. Using local GRB rate densities inferred from observations which are found in the science literature, we calculate estimates of the GWB detection rates for different configurations of the LIGO-Virgo network for this type of analysis.

  18. Life Disparity before, during and after Stagnation of Danish Female Life Expectancy. a Cause of Death Analysis and a Comparison with Their Scandinavian Counterparts

    DEFF Research Database (Denmark)

    Aburto, José Manuel; Wensink, Maarten Jan; Lindahl-Jacobsen, Rune

    Low lifespan tends to go with high lifespan inequality. We find that stagnation in lifespan of Danish women (roughly 1975-1995) was accompanied by a similar albeit shorter period of stagnation in lifespan inequality. Cause-specifically, we find that this stagnation results largely from death from...... cancers and non-infectious respiratory diseases, offsetting continuous improvement in cardiovascular mortality. Before and after stagnation, life expectancy increased as disparity decreased, as the cardiovascular revolution unfolded. Comparing Denmark and its Scandinavian counterparts, we find...... that as Norway increasingly came to resemble Sweden in terms of high life expectancy, it also came to resemble Sweden in terms of low lifespan inequality. Next, we aim to make similar decompositions for Sweden and Norway, and aim to disentangle cohort effects from the question: what can Denmark do now...

  19. The Electromagnetic Counterpart of the Binary Neutron Star Merger LIGO/Virgo GW170817. VII. Properties of the Host Galaxy and Constraints on the Merger Timescale

    Energy Technology Data Exchange (ETDEWEB)

    Blanchard, P. K.; Berger, E.; Fong, W.; Nicholl, M.; Leja, J.; Conroy, C.; Alexander, K. D.; Margutti, R.; Williams, P. K. G.; Doctor, Z.; Chornock, R.; Villar, V. A.; Cowperthwaite, P. S.; Annis, J.; Brout, D.; Brown, D. A.; Chen, H. -Y.; Eftekhari, T.; Frieman, J. A.; Holz, D. E.; Metzger, B. D.; Rest, A.; Sako, M.; Soares-Santos, M.

    2017-10-16

    We present the properties of NGC 4993, the host galaxy of GW170817, the first gravitational wave (GW) event from the merger of a binary neutron star (BNS) system and the first with an electromagnetic (EM) counterpart. We use both archival photometry and new optical/near-IR imaging and spectroscopy, together with stellar population synthesis models to infer the global properties of the host galaxy. We infer a star formation history peaked at $\\gtrsim 10$ Gyr ago, with subsequent exponential decline leading to a low current star formation rate of 0.01 M$_{\\odot}$ yr$^{-1}$, which we convert into a binary merger timescale probability distribution. We find a median merger timescale of $11.2^{+0.7}_{-1.4}$ Gyr, with a 90% confidence range of $6.8-13.6$ Gyr. This in turn indicates an initial binary separation of $\\approx 4.5$ R$_{\\odot}$, comparable to the inferred values for Galactic BNS systems. We also use new and archival $Hubble$ $Space$ $Telescope$ images to measure a projected offset of the optical counterpart of $2.1$ kpc (0.64$r_{e}$) from the center of NGC 4993 and to place a limit of $M_{r} \\gtrsim -7.2$ mag on any pre-existing emission, which rules out the brighter half of the globular cluster luminosity function. Finally, the age and offset of the system indicates it experienced a modest natal kick with an upper limit of $\\sim 200$ km s$^{-1}$. Future GW$-$EM observations of BNS mergers will enable measurement of their population delay time distribution, which will directly inform their viability as the dominant source of $r$-process enrichment in the Universe.

  20. Enzyme activity measurement via spectral evolution profiling and PARAFAC

    DEFF Research Database (Denmark)

    Baum, Andreas; Meyer, Anne S.; Garcia, Javier Lopez

    2013-01-01

    The recent advances in multi-way analysis provide new solutions to traditional enzyme activity assessment. In the present study enzyme activity has been determined by monitoring spectral changes of substrates and products in real time. The method relies on measurement of distinct spectral...... fingerprints of the reaction mixture at specific time points during the course of the whole enzyme catalyzed reaction and employs multi-way analysis to detect the spectral changes. The methodology is demonstrated by spectral evolution profiling of Fourier Transform Infrared (FTIR) spectral fingerprints using...

  1. Atmospheric parameters, spectral indexes and their relation to CPV spectral performance

    Energy Technology Data Exchange (ETDEWEB)

    Núñez, Rubén, E-mail: ruben.nunez@ies-def.upm.es; Antón, Ignacio, E-mail: ruben.nunez@ies-def.upm.es; Askins, Steve, E-mail: ruben.nunez@ies-def.upm.es; Sala, Gabriel, E-mail: ruben.nunez@ies-def.upm.es [Instituto de Energía Solar - Universidad Politécnica de Madrid, Instituto de Energía Solar, ETSI Telecomunicación, Ciudad Universitaria 28040 Madrid (Spain)

    2014-09-26

    Air Mass and atmosphere components (basically aerosol (AOD) and precipitable water (PW)) define the absorption of the sunlight that arrive to Earth. Radiative models such as SMARTS or MODTRAN use these parameters to generate an equivalent spectrum. However, complex and expensive instruments (as AERONET network devices) are needed to obtain AOD and PW. On the other hand, the use of isotype cells is a convenient way to characterize spectrally a place for CPV considering that they provide the photocurrent of the different internal subcells individually. Crossing data from AERONET station and a Tri-band Spectroheliometer, a model that correlates Spectral Mismatch Ratios and atmospheric parameters is proposed. Considering the amount of stations of AERONET network, this model may be used to estimate the spectral influence on energy performance of CPV systems close to all the stations worldwide.

  2. Spectrally based mapping of riverbed composition

    Science.gov (United States)

    Legleiter, Carl; Stegman, Tobin K.; Overstreet, Brandon T.

    2016-01-01

    Remote sensing methods provide an efficient means of characterizing fluvial systems. This study evaluated the potential to map riverbed composition based on in situ and/or remote measurements of reflectance. Field spectra and substrate photos from the Snake River, Wyoming, USA, were used to identify different sediment facies and degrees of algal development and to quantify their optical characteristics. We hypothesized that accounting for the effects of depth and water column attenuation to isolate the reflectance of the streambed would enhance distinctions among bottom types and facilitate substrate classification. A bottom reflectance retrieval algorithm adapted from coastal research yielded realistic spectra for the 450 to 700 nm range; but bottom reflectance-based substrate classifications, generated using a random forest technique, were no more accurate than classifications derived from above-water field spectra. Additional hypothesis testing indicated that a combination of reflectance magnitude (brightness) and indices of spectral shape provided the most accurate riverbed classifications. Convolving field spectra to the response functions of a multispectral satellite and a hyperspectral imaging system did not reduce classification accuracies, implying that high spectral resolution was not essential. Supervised classifications of algal density produced from hyperspectral data and an inferred bottom reflectance image were not highly accurate, but unsupervised classification of the bottom reflectance image revealed distinct spectrally based clusters, suggesting that such an image could provide additional river information. We attribute the failure of bottom reflectance retrieval to yield more reliable substrate maps to a latent correlation between depth and bottom type. Accounting for the effects of depth might have eliminated a key distinction among substrates and thus reduced discriminatory power. Although further, more systematic study across a broader

  3. Quality evaluation of tandem mass spectral libraries.

    Science.gov (United States)

    Oberacher, Herbert; Weinmann, Wolfgang; Dresen, Sebastian

    2011-06-01

    Tandem mass spectral libraries are gaining more and more importance for the identification of unknowns in different fields of research, including metabolomics, forensics, toxicology, and environmental analysis. Particularly, the recent invention of reliable, robust, and transferable libraries has increased the general acceptance of these tools. Herein, we report on results obtained from thorough evaluation of the match reliabilities of two tandem mass spectral libraries: the MSforID library established by the Oberacher group in Innsbruck and the Weinmann library established by the Weinmann group in Freiburg. Three different experiments were performed: (1) Spectra of the libraries were searched against their corresponding library after excluding either this single compound-specific spectrum or all compound-specific spectra prior to searching; (2) the libraries were searched against each other using either library as reference set or sample set; (3) spectra acquired on different mass spectrometric instruments were matched to both libraries. Almost 13,000 tandem mass spectra were included in this study. The MSforID search algorithm was used for spectral matching. Statistical evaluation of the library search results revealed that principally both libraries enable the sensitive and specific identification of compounds. Due to higher mass accuracy of the QqTOF compared with the QTrap instrument, matches to the MSforID library were more reliable when comparing spectra with both libraries. Furthermore, only the MSforID library was shown to be efficiently transferable to different kinds of tandem mass spectrometers, including "tandem-in-time" instruments; this is due to the coverage of a large range of different collision energy settings-including the very low range-which is an outstanding characteristics of the MSforID library.

  4. Spectral properties of electromagnetic turbulence in plasmas

    Directory of Open Access Journals (Sweden)

    D. Shaikh

    2009-03-01

    Full Text Available We report on the nonlinear turbulent processes associated with electromagnetic waves in plasmas. We focus on low-frequency (in comparison with the electron gyrofrequency nonlinearly interacting electron whistlers and nonlinearly interacting Hall-magnetohydrodynamic (H-MHD fluctuations in a magnetized plasma. Nonlinear whistler mode turbulence study in a magnetized plasma involves incompressible electrons and immobile ions. Two-dimensional turbulent interactions and subsequent energy cascades are critically influenced by the electron whisters that behave distinctly for scales smaller and larger than the electron skin depth. It is found that in whistler mode turbulence there results a dual cascade primarily due to the forward spectral migration of energy that coexists with a backward spectral transfer of mean squared magnetic potential. Finally, inclusion of the ion dynamics, resulting from a two fluid description of the H-MHD plasma, leads to several interesting results that are typically observed in the solar wind plasma. Particularly in the solar wind, the high-time-resolution databases identify a spectral break at the end of the MHD inertial range spectrum that corresponds to a high-frequency regime. In the latter, turbulent cascades cannot be explained by the usual MHD model and a finite frequency effect (in comparison with the ion gyrofrequency arising from the ion inertia is essentially included to discern the dynamics of the smaller length scales (in comparison with the ion skin depth. This leads to a nonlinear H-MHD model, which is presented in this paper. With the help of our 3-D H-MHD code, we find that the characteristic turbulent interactions in the high-frequency regime evolve typically on kinetic-Alfvén time-scales. The turbulent fluctuation associated with kinetic-Alfvén interactions are compressive and anisotropic and possess equipartition of the kinetic and magnetic energies.

  5. Infrared spectral reflectances of asteroid surfaces

    Science.gov (United States)

    Larson, H. P.; Veeder, G. J.

    1979-01-01

    This review compares the types of compositional information produced by three complementary techniques used in infrared observations of asteroid surfaces: broadband JHKL photometry, narrow band photometry, and multiplex spectroscopy. The high information content of these infrared observations permits definitive interpretations of asteroid surface compositions in terms of the major meteoritic minerals (olivine, pyroxene, plagioclase feldspar, hydrous silicates, and metallic Ni-Fe). These studies emphasize the individuality of asteroid surface compositions, the inadequacy of simple comparisons with spectra of meteorites, and the need to coordinate spectral measurements of all types to optimize diagnostic capabilities.

  6. Storage and retrieval of mass spectral information

    Science.gov (United States)

    Hohn, M. E.; Humberston, M. J.; Eglinton, G.

    1977-01-01

    Computer handling of mass spectra serves two main purposes: the interpretation of the occasional, problematic mass spectrum, and the identification of the large number of spectra generated in the gas-chromatographic-mass spectrometric (GC-MS) analysis of complex natural and synthetic mixtures. Methods available fall into the three categories of library search, artificial intelligence, and learning machine. Optional procedures for coding, abbreviating and filtering a library of spectra minimize time and storage requirements. Newer techniques make increasing use of probability and information theory in accessing files of mass spectral information.

  7. Spectral Classification of Asteroids by Random Forest

    Science.gov (United States)

    Huang, Chao; Ma, Yue-hua; Zhao, Hai-bin; Lu, Xiao-ping

    2017-10-01

    With the increasing spectral and photometric data of asteroids, a variety of classification methods for asteroids have been proposed. This paper classifies asteroids based on the observations in the Sloan Digital Sky Survey (SDSS) Moving Object Catalogue (MOC) by using the random forest algorithm. In combination with the present taxonomies of Tholen, Bus, Lazzaro, and DeMeo, and the principal component analysis, we have classified 48642 asteroids according to their SDSS magnitudes at the g, r, i, and z wavebands. In this way, these asteroids are divided into 8 (C, X, S, B, D, K, L, and V) classes.

  8. Deformation effect on spectral statistics of nuclei

    Science.gov (United States)

    Sabri, H.; Jalili Majarshin, A.

    2018-02-01

    In this study, we tried to get significant relations between the spectral statistics of atomic nuclei and their different degrees of deformations. To this aim, the empirical energy levels of 109 even-even nuclei in the 22 ≤ A ≤ 196 mass region are classified as their experimental and calculated quadrupole, octupole, hexadecapole and hexacontatetrapole deformations values and analyzed by random matrix theory. Our results show an obvious relation between the regularity of nuclei and strong quadrupole, hexadecapole and hexacontatetrapole deformations and but for nuclei that their octupole deformations are nonzero, we have observed a GOE-like statistics.

  9. Mixed-Precision Spectral Deferred Correction: Preprint

    Energy Technology Data Exchange (ETDEWEB)

    Grout, Ray W. S.

    2015-09-02

    Convergence of spectral deferred correction (SDC), where low-order time integration methods are used to construct higher-order methods through iterative refinement, can be accelerated in terms of computational effort by using mixed-precision methods. Using ideas from multi-level SDC (in turn based on FAS multigrid ideas), some of the SDC correction sweeps can use function values computed in reduced precision without adversely impacting the accuracy of the final solution. This is particularly beneficial for the performance of combustion solvers such as S3D [6] which require double precision accuracy but are performance limited by the cost of data motion.

  10. YGFP: a spectral variant of GFP

    DEFF Research Database (Denmark)

    Hansen, Flemming G.; Atlung, Tove

    2011-01-01

    We describe YGFP, a slow bleaching green fluorescent protein (GFP) with unique spectral properties. YGFP is derived from an Escherichia coli codon-optimized synthetic gfp, mutant 2 derivative. In addition to the GFP-mut 2 changes, it also carries S202F and T203I substitutions. YGFP can be used...... as a substitute for yellow fluorescent protein (YFP) in experiments in which two or more fluorescent proteins are fused to different cellular protein components, expanding the ability to study multiple labeled proteins in a cell at once....

  11. An experiment of spectral induced polarization

    Directory of Open Access Journals (Sweden)

    L. Sambuelli

    1994-06-01

    Full Text Available A Spectral Induced Polarization (SIP survey was carried out in a mining test site in Sardinia (Italy. Measurements were developed along a profile by using an axial dipole-dipole array with 10 AB positions and 6 MN positions for cach AB. The amplitude and phase spectra of the apparent resistivity were acquired in the 0.25-4096 Hz frequeney range. The results obtained through the processing and inversion step seem to confirm that, with respect to the classical TD/FD Induced Polarization, SIP allows better discrimination of some important characteristics of mineral deposits such as mineral content and grain size.

  12. 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

  13. Spectral difference methods for solving differential equations

    Science.gov (United States)

    Mazziotti, David A.

    1999-01-01

    A family of recently developed techniques is explored for achieving both matrix sparsity and rapid convergence when numerically solving differential and eigenvalue equations without domain decomposition. These methods, which we call spectral differences, include Boyd's sum acceleration techniques and the Lagrange distributed approximating functional (LDAF) approach. A formula is developed for estimating the unknown Gaussian parameter within LDAF. We implement these methods to calculate the Morse vibrational energies for diatomic iodine. For equivalent bandwidths the sum acceleration with finite difference weights generates energies which are between two and three orders of magnitude more accurate than those from LDAF.

  14. Improving dimensionality reduction with spectral gradient descent.

    Science.gov (United States)

    Memisevic, Roland; Hinton, Geoffrey

    2005-01-01

    We introduce spectral gradient descent, a way of improving iterative dimensionality reduction techniques. The method uses information contained in the leading eigenvalues of a data affinity matrix to modify the steps taken during a gradient-based optimization procedure. We show that the approach is able to speed up the optimization and to help dimensionality reduction methods find better local minima of their objective functions. We also provide an interpretation of our approach in terms of the power method for finding the leading eigenvalues of a symmetric matrix and verify the usefulness of the approach in some simple experiments.

  15. Semiclassical universality of parametric spectral correlations

    International Nuclear Information System (INIS)

    Kuipers, Jack; Sieber, Martin

    2007-01-01

    We consider quantum systems with a chaotic classical limit that depends on an external parameter, and study correlations between the spectra at different parameter values. In particular, we consider the parametric spectral form factor K(τ, x) which depends on a scaled parameter difference x. For parameter variations that do not change the symmetry of the system we show by using semiclassical periodic orbit expansions that the small τ expansion of the form factor agrees with random matrix theory for systems with and without time reversal symmetry

  16. Spectral density regression for bivariate extremes

    KAUST Repository

    Castro Camilo, Daniela

    2016-05-11

    We introduce a density regression model for the spectral density of a bivariate extreme value distribution, that allows us to assess how extremal dependence can change over a covariate. Inference is performed through a double kernel estimator, which can be seen as an extension of the Nadaraya–Watson estimator where the usual scalar responses are replaced by mean constrained densities on the unit interval. Numerical experiments with the methods illustrate their resilience in a variety of contexts of practical interest. An extreme temperature dataset is used to illustrate our methods. © 2016 Springer-Verlag Berlin Heidelberg

  17. Programmable spectral design and the binary supergrating

    Science.gov (United States)

    Levner, Daniel

    Spectral operations such as wavelength selection, power level manipulation, and chromatic dispersion control are key to many processes in optical telecommunication, spectroscopy, and sensing. In their simplest forms, these functions can be performed using a number of successful devices such as the Fraunhofer ("diffraction") grating, Bragg grating, thin-film filter (TFF), and dispersion-compensating fiber (DCF). More complicated manipulations, however, often require either problematic cascades of many simple elements, the use of custom technologies that offer little adjustment, or the implementation of fully programmable devices, which allow for the desired spectral function to be synthesized ab initio. Here, I present the Binary Supergrating (BSG), a novel technology that permits the programmable and near-arbitrary control of optical amplitude and phase using a simple, robust and practical form. This guided-wave form consists of an aperiodic sequence of binary elements; the sequence, determined through the process of BSG synthesis, encodes an optical program that defines device functionality. The ability to derive optical programs that address broad spectral demands is central to the BSG's extensive capabilities. In consequence, I present a powerful approach to synthesis that exploits existing knowledge in the design of "analog" gratings. This approach is based on a two-step process, which first derives an analog diffractive structure using the best available methods and then transforms it into binary form. Accordingly, I discuss the notion of diffractive structure transformation and introduce the principle of key information. I identify such key information and illustrate its application in grating quantizers based on an atypical form of Delta-Sigma modulation. As a digital approach to spectral engineering, the BSG presents many of the same advantages offered by the digital approach to electronic signal processing (DSP) over its analog predecessors. As such, it

  18. Spectral Analysis Methods of Social Networks

    Directory of Open Access Journals (Sweden)

    P. G. Klyucharev

    2017-01-01

    Full Text Available Online social networks (such as Facebook, Twitter, VKontakte, etc. being an important channel for disseminating information are often used to arrange an impact on the social consciousness for various purposes - from advertising products or services to the full-scale information war thereby making them to be a very relevant object of research. The paper reviewed the analysis methods of social networks (primarily, online, based on the spectral theory of graphs. Such methods use the spectrum of the social graph, i.e. a set of eigenvalues of its adjacency matrix, and also the eigenvectors of the adjacency matrix.Described measures of centrality (in particular, centrality based on the eigenvector and PageRank, which reflect a degree of impact one or another user of the social network has. A very popular PageRank measure uses, as a measure of centrality, the graph vertices, the final probabilities of the Markov chain, whose matrix of transition probabilities is calculated on the basis of the adjacency matrix of the social graph. The vector of final probabilities is an eigenvector of the matrix of transition probabilities.Presented a method of dividing the graph vertices into two groups. It is based on maximizing the network modularity by computing the eigenvector of the modularity matrix.Considered a method for detecting bots based on the non-randomness measure of a graph to be computed using the spectral coordinates of vertices - sets of eigenvector components of the adjacency matrix of a social graph.In general, there are a number of algorithms to analyse social networks based on the spectral theory of graphs. These algorithms show very good results, but their disadvantage is the relatively high (albeit polynomial computational complexity for large graphs.At the same time it is obvious that the practical application capacity of the spectral graph theory methods is still underestimated, and it may be used as a basis to develop new methods.The work

  19. Spectral evolution of dwarf nova outbursts

    International Nuclear Information System (INIS)

    Cannizzo, J.K.; Kenyon, S.J.

    1987-01-01

    The disk instability model for dwarf nova eruptions is investigated by computing the spectral development of the accretion disk through a complete limit cycle. Observed stellar spectra are used to model the radiation emitted by optically thick annuli within the disc. The general findings agree with those of Smak (1984) and Pringle et al. (1986). It is suggested that the dwarf nova oscillations might be a source of information concerning the evolution of the inner disk and that detailed observations of this phenomenon can be used to test various outburst mechanisms. 74 references

  20. Spectral Hounsfield units: a new radiological concept

    International Nuclear Information System (INIS)

    Hurrell, Michael Anthony; Butler, Anthony Philip Howard; Cook, Nicholas James; Butler, Philip Howard; Ronaldson, J.P.; Zainon, Rafidah

    2012-01-01

    Computed tomography (CT) uses radiographical density to depict different materials; although different elements have different absorption fingerprints across the range of diagnostic X-ray energies, this spectral absorption information is lost in conventional CT. The recent development of dual energy CT (DECT) allows extraction of this information to a useful but limited extent. However, the advent of new photon counting chips that have energy resolution capabilities has put multi-energy or spectral CT (SCT) on the clinical horizon. This paper uses a prototype SCT system to demonstrate how CT density measurements vary with kilovoltage. While radiologists learn about linear attenuation curves during radiology training, they do not usually need a detailed understanding of this phenomenon in their clinical practice. However SCT requires a paradigm shift in how radiologists think about CT density. Because radiologists are already familiar with the Hounsfield Unit (HU), it is proposed that a modified HU be used that includes the mean energy used to obtain the image, as a conceptual bridge between conventional CT and SCT. A suggested format would be: HU keV . (orig.)

  1. Recursive and Fast Recursive Capon Spectral Estimators

    Directory of Open Access Journals (Sweden)

    Chen Jingdong

    2007-01-01

    Full Text Available The Capon algorithm, which was originally proposed for wavenumber estimation in array signal processing, has become a powerful tool for spectral analysis. Over several decades, a significant amount of research attention has been devoted to the estimation of the Capon spectrum. Most of the developed algorithms thus far, however, rely on the direct computation of the inverse of the input correlation (or covariance matrix, which can be computationally very expensive particularly when the dimension of the matrix is large. This paper deals with fast and efficient algorithms in computing the Capon spectrum. Inspired from the recursive idea established in adaptive signal processing theory, we first derive a recursive Capon algorithm. This new algorithm does not require an explicit matrix inversion, and hence it is more efficient to implement than the direct-inverse approach. We then develop a fast version of the recursive algorithm based on techniques used in fast recursive least-squares adaptive algorithms. This new fast algorithm can further reduce the complexity of the recursive Capon algorithm by an order of magnitude. Although our focus is on the Capon spectral estimation, the ideas shown in this paper can also be generalized and applied to other applications. To illustrate this, we will show how to apply the recursive idea to the estimation of the magnitude squared coherence function, which plays an important role for problems like time-delay estimation, signal-to-noise ratio estimation, and doubletalk detection in echo cancellation.

  2. Multitaper spectral analysis of atmospheric radar signals

    Directory of Open Access Journals (Sweden)

    V. K. Anandan

    2004-11-01

    Full Text Available Multitaper spectral analysis using sinusoidal taper has been carried out on the backscattered signals received from the troposphere and lower stratosphere by the Gadanki Mesosphere-Stratosphere-Troposphere (MST radar under various conditions of the signal-to-noise ratio. Comparison of study is made with sinusoidal taper of the order of three and single tapers of Hanning and rectangular tapers, to understand the relative merits of processing under the scheme. Power spectra plots show that echoes are better identified in the case of multitaper estimation, especially in the region of a weak signal-to-noise ratio. Further analysis is carried out to obtain three lower order moments from three estimation techniques. The results show that multitaper analysis gives a better signal-to-noise ratio or higher detectability. The spectral analysis through multitaper and single tapers is subjected to study of consistency in measurements. Results show that the multitaper estimate is better consistent in Doppler measurements compared to single taper estimates. Doppler width measurements with different approaches were studied and the results show that the estimation was better in the multitaper technique in terms of temporal resolution and estimation accuracy.

  3. Kernel spectral clustering with memory effect

    Science.gov (United States)

    Langone, Rocco; Alzate, Carlos; Suykens, Johan A. K.

    2013-05-01

    Evolving graphs describe many natural phenomena changing over time, such as social relationships, trade markets, metabolic networks etc. In this framework, performing community detection and analyzing the cluster evolution represents a critical task. Here we propose a new model for this purpose, where the smoothness of the clustering results over time can be considered as a valid prior knowledge. It is based on a constrained optimization formulation typical of Least Squares Support Vector Machines (LS-SVM), where the objective function is designed to explicitly incorporate temporal smoothness. The latter allows the model to cluster the current data well and to be consistent with the recent history. We also propose new model selection criteria in order to carefully choose the hyper-parameters of our model, which is a crucial issue to achieve good performances. We successfully test the model on four toy problems and on a real world network. We also compare our model with Evolutionary Spectral Clustering, which is a state-of-the-art algorithm for community detection of evolving networks, illustrating that the kernel spectral clustering with memory effect can achieve better or equal performances.

  4. ALEPH Tau Spectral Functions and QCD

    CERN Document Server

    Davier, M; Zhang, Z; Davier, Michel; Hoecker, Andreas; Zhang, Zhiqing

    2007-01-01

    Hadronic $\\tau$ decays provide a clean laboratory for the precise study of quantum chromodynamics (QCD). Observables based on the spectral functions of hadronic $\\tau$ decays can be related to QCD quark-level calculations to determine fundamental quantities like the strong coupling constant, quark and gluon condensates. Using the ALEPH spectral functions and branching ratios, complemented by some other available measurements, and a revisited analysis of the theoretical framework, the value $\\asm = 0.345 \\pm 0.004_{\\rm exp} \\pm 0.009_{\\rm th}$ is obtained. Taken together with the determination of \\asZ from the global electroweak fit, this result leads to the most accurate test of asymptotic freedom: the value of the logarithmic slope of $\\alpha_s^{-1}(s)$ is found to agree with QCD at a precision of 4%. The value of \\asZ obtained from $\\tau$ decays is $\\asZ = 0.1215 \\pm 0.0004_{\\rm exp} \\pm 0.0010_{\\rm th} \\pm 0.0005_{\\rm evol} = 0.1215 \\pm 0.0012$.

  5. Spectral analysis and the Riemann hypothesis

    Science.gov (United States)

    Lachaud, Gilles

    2003-11-01

    The explicit formulas of Riemann and Guinand-Weil relate the set of prime numbers with the set of nontrivial zeros of the zeta function of Riemann. We recall Alain Connes' spectral interpretation of the critical zeros of the Riemann zeta function as eigenvalues of the absorption spectrum of an unbounded operator in a suitable Hilbert space. We then give a spectral interpretation of the zeros of the Dedekind zeta function of an algebraic number field K of degree n in an automorphic setting. If K is a complex quadratic field, the torical forms are the functions defined on the modular surface X, such that the sum of this function over the "Gauss set" of K is zero, and Eisenstein series provide such torical forms. In the case of a general number field, one can associate to K a maximal torus T of the general linear group G. The torical forms are the functions defined on the modular variety X associated to G, such that the integral over the subvariety induced by T is zero. Alternately, the torical forms are the functions which are orthogonal to orbital series on X. We show here that the Riemann hypothesis is equivalent to certain conditions bearing on spaces of torical forms, constructed from Eisenstein series, the torical wave packets. Furthermore, we define a Hilbert space and a self-adjoint operator on this space, whose spectrum equals the set of critical zeros of the Dedekind zeta function of K.

  6. Function of snake mobbing in spectral tarsiers.

    Science.gov (United States)

    Gursky, Sharon

    2006-04-01

    Numerous species are known for their tendency to approach and confront their predators as a group. This behavior is known as mobbing. Snakes seem to be one of the more consistent recipients of this type of predator-directed behavior. This paper explores individual differences (sex and age) in the mobbing behavior of the spectral tarsier toward live and model snakes. This study was conducted at Tangkoko Nature Reserve (Sulawesi, Indonesia) during 2003-2004. During this research, 11 natural mobbing events and 31 artificially induced mobbing events were observed. The mean number of individuals at a mobbing was 5.7. The duration of mobbing events was strongly correlated with the number of assembled mobbers. Adults were more likely than other age classes to participate in mobbings. Males were more likely than females to participate in mobbings. Mobbing groups often contained more than one adult male, despite the fact that no spectral tarsier group contains more than one adult male. No difference in body size between extragroup males and resident males was observed, refuting the "attract the mightier" hypothesis. The number of mobbers did not affect whether the tarsier or the snake retreated first, countering the "move-on" hypothesis. The "perception advertisement" hypothesis was tentatively supported, in that live snakes were rarely seen in the area following mobbing calls, in comparison to when tarsiers either ignored the snake or alarm call. Copyright 2006 Wiley-Liss, Inc.

  7. Mercury's Pyroclastic Deposits and their spectral variability

    Science.gov (United States)

    Besse, Sebastien; Doressoundiram, Alain

    2016-10-01

    Observations of the MESSENGER spacecraft in orbit around Mercury have shown that volcanism is a very important process that has shaped the surface of the planet, in particular in its early history.In this study, we use the full range of the MASCS spectrometer (300-1400nm) to characterize the spectral properties of the pyroclastic deposits. Analysis of deposits within the Caloris Basin, and on other location of Mercury's surface (e.g., Hesiod, Rachmaninoff, etc.) show two main results: 1) Spectral variability is significant in the UV and VIS range between the deposits themselves, and also with respect to the rest of the planet and other features like hollows, 2) Deposits exhibit a radial variability similar to those found with the lunar pyroclastic deposits of floor fractured craters.These results are put in context with the latest analysis of other instruments of the MESSENGER spacecraft, in particular the visible observations from the imager MDIS, and the elemental composition given by the X-Ray spectrometer. Although all together, the results do not allow pointing to compositional variability of the deposits for certain, information on the formation mechanisms, the weathering and the age formation can be extrapolated from the radial variability and the elemental composition.

  8. EXOPLANETARY DETECTION BY MULTIFRACTAL SPECTRAL ANALYSIS

    Energy Technology Data Exchange (ETDEWEB)

    Agarwal, Sahil; Wettlaufer, John S. [Program in Applied Mathematics, Yale University, New Haven, CT (United States); Sordo, Fabio Del [Department of Astronomy, Yale University, New Haven, CT (United States)

    2017-01-01

    Owing to technological advances, the number of exoplanets discovered has risen dramatically in the last few years. However, when trying to observe Earth analogs, it is often difficult to test the veracity of detection. We have developed a new approach to the analysis of exoplanetary spectral observations based on temporal multifractality, which identifies timescales that characterize planetary orbital motion around the host star and those that arise from stellar features such as spots. Without fitting stellar models to spectral data, we show how the planetary signal can be robustly detected from noisy data using noise amplitude as a source of information. For observation of transiting planets, combining this method with simple geometry allows us to relate the timescales obtained to primary and secondary eclipse of the exoplanets. Making use of data obtained with ground-based and space-based observations we have tested our approach on HD 189733b. Moreover, we have investigated the use of this technique in measuring planetary orbital motion via Doppler shift detection. Finally, we have analyzed synthetic spectra obtained using the SOAP 2.0 tool, which simulates a stellar spectrum and the influence of the presence of a planet or a spot on that spectrum over one orbital period. We have demonstrated that, so long as the signal-to-noise-ratio ≥ 75, our approach reconstructs the planetary orbital period, as well as the rotation period of a spot on the stellar surface.

  9. Exploratory Item Classification Via Spectral Graph Clustering.

    Science.gov (United States)

    Chen, Yunxiao; Li, Xiaoou; Liu, Jingchen; Xu, Gongjun; Ying, Zhiliang

    2017-01-01

    Large-scale assessments are supported by a large item pool. An important task in test development is to assign items into scales that measure different characteristics of individuals, and a popular approach is cluster analysis of items. Classical methods in cluster analysis, such as the hierarchical clustering, K-means method, and latent-class analysis, often induce a high computational overhead and have difficulty handling missing data, especially in the presence of high-dimensional responses. In this article, the authors propose a spectral clustering algorithm for exploratory item cluster analysis. The method is computationally efficient, effective for data with missing or incomplete responses, easy to implement, and often outperforms traditional clustering algorithms in the context of high dimensionality. The spectral clustering algorithm is based on graph theory, a branch of mathematics that studies the properties of graphs. The algorithm first constructs a graph of items, characterizing the similarity structure among items. It then extracts item clusters based on the graphical structure, grouping similar items together. The proposed method is evaluated through simulations and an application to the revised Eysenck Personality Questionnaire.

  10. Spectral intensities in trivalent lanthanide systems

    Energy Technology Data Exchange (ETDEWEB)

    Acevedo, Roberto [Facultad de Ingenieria, Universidad Mayor, Avenida Manuel Montt 367, Postal code 7500994, Providencia, Santiago (Chile)], E-mail: roberto.acevedo@umayor.cl; Soto-Bubert, Andres; Bosch, Paul [Instituto de Ciencias Basicas, Facultad de Ingenieria, Universidad Diego Portales, Avenida Ejercito 441, Casilla 298-V, Santiago (Chile); Strek, Wieslaw [Institute of Low Temperature and Structure Research, Polish Academy of Sciences, Okoelna 2, 50-422 Wroclaw (Poland)

    2008-08-11

    The main goal of this research work is to rationalize the rich vibronic structure of lanthanide type crystals, such as Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6}, in the space group Fm3m(O{sub h}{sup 5}). These systems are known to be highly relativistic and as a consequence, major corrections to previous model calculations should be taken into account so as to explain from a semi-quantitative viewpoint, the observed spectral intensities. We have decided to tackle this study taking special care, of both the physics and the chemistry involved with special emphasis on the theoretical model to be employed as well as, in the strategy to be followed to rationalize the available experimental data. This paper aims to advance our understanding of the intensity mechanisms, associated with observed radiative transitions, say for complex highly relativistic systems, in the solid state physics. The spectral intensities associated with superpositions (juxtapositions) of peaks and/or bands in the absortion and emission spectra are considered in detail and a preliminary working methodology is put forward with reference to the Cs{sub 2}NaDyCl{sub 6} and Cs{sub 2}NaHoCl{sub 6} crystals.

  11. CMB spectral distortion constraints on thermal inflation

    Energy Technology Data Exchange (ETDEWEB)

    Cho, Kihyun; Stewart, Ewan D. [Department of Physics, KAIST, Daejeon 34141 (Korea, Republic of); Hong, Sungwook E. [Korea Astronomy and Space Science Institute, Daejeon 34055 (Korea, Republic of); Zoe, Heeseung, E-mail: cho_physics@kaist.ac.kr, E-mail: heezoe@dgist.ac.kr, E-mail: jcap@profstewart.org, E-mail: heezoe@dgist.ac.kr [School of Undergraduate Studies, College of Transdisciplinary Studies, Daegu Gyeongbuk Institute of Science and Technology (DGIST), Daegu 42988 (Korea, Republic of)

    2017-08-01

    Thermal inflation is a second epoch of exponential expansion at typical energy scales V {sup 1/4} ∼ 10{sup 6} {sup ∼} {sup 8} GeV. If the usual primordial inflation is followed by thermal inflation, the primordial power spectrum is only modestly redshifted on large scales, but strongly suppressed on scales smaller than the horizon size at the beginning of thermal inflation, k > k {sub b} = a {sub b} H {sub b}. We calculate the spectral distortion of the cosmic microwave background generated by the dissipation of acoustic waves in this context. For k {sub b} || 10{sup 3} Mpc{sup −1}, thermal inflation results in a large suppression of the μ-distortion amplitude, predicting that it falls well below the standard value of μ ≅ 2× 10{sup −8}. Thus, future spectral distortion experiments, similar to PIXIE, can place new limits on the thermal inflation scenario, constraining k {sub b} ∼> 10{sup 3} Mpc{sup −1} if μ ≅ 2× 10{sup −8} were found.

  12. Spectrally resolved single-molecule electrometry

    Science.gov (United States)

    Ruggeri, F.; Krishnan, M.

    2018-03-01

    Escape-time electrometry is a recently developed experimental technique that offers the ability to measure the effective electrical charge of a single biomolecule in solution with sub-elementary charge precision. The approach relies on measuring the average escape-time of a single charged macromolecule or molecular species transiently confined in an electrostatic fluidic trap. Comparing the experiments with the predictions of a mean-field model of molecular electrostatics, we have found that the measured effective charge even reports on molecular conformation, e.g., folded or disordered state, and non-uniform charge distribution in disordered proteins or polyelectrolytes. Here we demonstrate the ability to use the spectral dimension to distinguish minute differences in electrical charge between individual molecules or molecular species in a single simultaneous measurement, under identical experimental conditions. Using one spectral channel for referenced measurement, this kind of photophysical distinguishability essentially eliminates the need for accurate knowledge of key experimental parameters, otherwise obtained through intensive characterization of the experimental setup. As examples, we demonstrate the ability to detect small differences (˜5%) in the length of double-stranded DNA fragments as well as single amino acid exchange in an intrinsically disordered protein, prothymosin α.

  13. Spectral Clustering of Hermean craters hollows

    Science.gov (United States)

    Lucchetti, Alice; Pajola, Maurizio; Cremonese, Gabriele; Carli, Cristian; Marzo, Giuseppe; Roush, Ted

    2017-04-01

    The Mercury Dual Imaging System (MDIS, Hawkins et al., 2007) onboard NASA MESSENGER (MErcury Surface, Space ENvironment, GEochemistry, and Ranging) spacecraft, provided high-resolution images of "hollows", i.e. shallow, irregular, rimless, flat-floored depressions with bright interiors and halos, often found on crater walls, rims, floors and central peaks (Blewett et al., 2011, 2013). The formation mechanism of these features was suggested to be related to the depletion of subsurface volatiles (Blewett et al., 2011, Vaughan et al., 2012). To understand the hollows' mineralogical composition, which can provide new insights on Mercury's surface characterization, we applied a spectral clustering method to different craters where hollows are present. We chose, as first test case, the 20 km wide Dominici crater due to previous multiple spectral detection (Vilas et al., 2016). We used the MDIS WAC dataset covering Dominici crater with a scale of 935 m/pixel through eight filters, ranging from 0.433 to 0.996 μm. First, the images have been photometrically corrected using the Hapke parameters (Hapke et al., 2002) derived in Domingue et al. (2015). We then applied a statistical clustering over the entire dataset based on a K-means partitioning algorithm (Marzo et al., 2006). This approach was developed and evaluated by Marzo et al. (2006, 2008, 2009) and makes use of the Calinski and Harabasz criterion (Calinski, T., Harabasz, J., 1974) to identify the intrinsically natural number of clusters, making the process unsupervised. The natural number of ten clusters was identified and spectrally separates the Dominici surrounding terrains from its interior, as well as the two hollows from their edges. The units located on the brightest part of the south wall/rim of Dominici crater clearly present a wide absorption band between 0.558 and 0.828 μm. Hollows surrounding terrains typically present a red slope in the VNIR with a possible weak absorption band centered at 0.748

  14. High speed parallel spectral-domain OCT using spectrally encoded line-field illumination

    Science.gov (United States)

    Lee, Kye-Sung; Hur, Hwan; Bae, Ji Yong; Kim, I. Jong; Kim, Dong Uk; Nam, Ki-Hwan; Kim, Geon-Hee; Chang, Ki Soo

    2018-01-01

    We report parallel spectral-domain optical coherence tomography (OCT) at 500 000 A-scan/s. This is the highest-speed spectral-domain (SD) OCT system using a single line camera. Spectrally encoded line-field scanning is proposed to increase the imaging speed in SD-OCT effectively, and the tradeoff between speed, depth range, and sensitivity is demonstrated. We show that three imaging modes of 125k, 250k, and 500k A-scan/s can be simply switched according to the sample to be imaged considering the depth range and sensitivity. To demonstrate the biological imaging performance of the high-speed imaging modes of the spectrally encoded line-field OCT system, human skin and a whole leaf were imaged at the speed of 250k and 500k A-scan/s, respectively. In addition, there is no sensitivity dependence in the B-scan direction, which is implicit in line-field parallel OCT using line focusing of a Gaussian beam with a cylindrical lens.

  15. Spectral analysis of a class of Schrodinger operators exhibiting a parameter-dependent spectral transition

    Czech Academy of Sciences Publication Activity Database

    Barseghyan, Diana; Exner, Pavel; Khrabustovskyi, A.; Tater, Miloš

    2016-01-01

    Roč. 49, č. 16 (2016), s. 165302 ISSN 1751-8113 R&D Projects: GA ČR(CZ) GA14-06818S Institutional support: RVO:61389005 Keywords : Schrodinger operator * eigenvalue estimates * spectral transition Subject RIV: BE - Theoretical Physics Impact factor: 1.857, year: 2016

  16. Upconversion based spectral imaging in 6 to 8 μm spectral regime

    DEFF Research Database (Denmark)

    Junaid, Saher; Tidemand-Lichtenberg, Peter; Pedersen, Christian

    2017-01-01

    Spectral imaging in the 6 to 8μm range has great potential for medical diagnostics. Here a novel technique based on frequency upconversion of the infrared images to the near visible for subsequent acquisition using a Si-CCD camera is investigated. The upconversion unit consists of an AgGaS2 crystal...

  17. Magnetotelluric (MT) data smoothing based on B-Spline algorithm and qualitative spectral analysis

    Science.gov (United States)

    Handyarso, Accep; Grandis, Hendra

    2017-07-01

    Data processing is one of the essential steps to obtain optimum response function of the Earth's subsurface. The MT Data processing is based on the Fast Fourier Transform (FFT) algorithm which converts the time series data into its frequency domain counterpart. The FFT combined with statistical algorithm constitute the Robust Processing algorithm which is widely implemented in MT data processing software. The Robust Processing has three variants, i.e. No Weight (NW), Rho Variance (RV), and Ordinary Coherency (OC). The RV and OC options allow for denoising the data but in many cases the Robust Processing still results in not so smooth sounding curve due to strong noise presence during measurement, such that the Crosspower (XPR) analysis must be conducted in the data processing. The XPR analysis is very time consuming step within the data processing. The collaboration of B-Spline algorithm and Qualitative Spectral Analysis in the frequency domain could be of advantages as an alternative for these steps. The technique is started by using the best coherency from the Robust Processing results. In the Qualitative Spectral Analysis one can determine which part of the data based on frequency that is more or less reliable, then the next process invokes B-Spline algorithm for data smoothing. This algorithm would select the best fit of the data trend in the frequency domain. The smooth apparent resistivity and phase sounding curves can be considered as more appropriate to represent the subsurface. This algorithm has been applied to the real MT data from several survey and give satisfactory results.

  18. Spectral signature verification using statistical analysis and text mining

    Science.gov (United States)

    DeCoster, Mallory E.; Firpi, Alexe H.; Jacobs, Samantha K.; Cone, Shelli R.; Tzeng, Nigel H.; Rodriguez, Benjamin M.

    2016-05-01

    In the spectral science community, numerous spectral signatures are stored in databases representative of many sample materials collected from a variety of spectrometers and spectroscopists. Due to the variety and variability of the spectra that comprise many spectral databases, it is necessary to establish a metric for validating the quality of spectral signatures. This has been an area of great discussion and debate in the spectral science community. This paper discusses a method that independently validates two different aspects of a spectral signature to arrive at a final qualitative assessment; the textual meta-data and numerical spectral data. Results associated with the spectral data stored in the Signature Database1 (SigDB) are proposed. The numerical data comprising a sample material's spectrum is validated based on statistical properties derived from an ideal population set. The quality of the test spectrum is ranked based on a spectral angle mapper (SAM) comparison to the mean spectrum derived from the population set. Additionally, the contextual data of a test spectrum is qualitatively analyzed using lexical analysis text mining. This technique analyzes to understand the syntax of the meta-data to provide local learning patterns and trends within the spectral data, indicative of the test spectrum's quality. Text mining applications have successfully been implemented for security2 (text encryption/decryption), biomedical3 , and marketing4 applications. The text mining lexical analysis algorithm is trained on the meta-data patterns of a subset of high and low quality spectra, in order to have a model to apply to the entire SigDB data set. The statistical and textual methods combine to assess the quality of a test spectrum existing in a database without the need of an expert user. This method has been compared to other validation methods accepted by the spectral science community, and has provided promising results when a baseline spectral signature is

  19. The Open Spectral Database: an open platform for sharing and searching spectral data.

    Science.gov (United States)

    Chalk, Stuart J

    2016-01-01

    A number of websites make available spectral data for download (typically as JCAMP-DX text files) and one (ChemSpider) that also allows users to contribute spectral files. As a result, searching and retrieving such spectral data can be time consuming, and difficult to reuse if the data is compressed in the JCAMP-DX file. What is needed is a single resource that allows submission of JCAMP-DX files, export of the raw data in multiple formats, searching based on multiple chemical identifiers, and is open in terms of license and access. To address these issues a new online resource called the Open Spectral Database (OSDB) http://osdb.info/ has been developed and is now available. Built using open source tools, using open code (hosted on GitHub), providing open data, and open to community input about design and functionality, the OSDB is available for anyone to submit spectral data, making it searchable and available to the scientific community. This paper details the concept and coding, internal architecture, export formats, Representational State Transfer (REST) Application Programming Interface and options for submission of data. The OSDB website went live in November 2015. Concurrently, the GitHub repository was made available at https://github.com/stuchalk/OSDB/, and is open for collaborators to join the project, submit issues, and contribute code. The combination of a scripting environment (PHPStorm), a PHP Framework (CakePHP), a relational database (MySQL) and a code repository (GitHub) provides all the capabilities to easily develop REST based websites for ingestion, curation and exposure of open chemical data to the community at all levels. It is hoped this software stack (or equivalent ones in other scripting languages) will be leveraged to make more chemical data available for both humans and computers.

  20. Development of Jet Noise Power Spectral Laws

    Science.gov (United States)

    Khavaran, Abbas; Bridges, James

    2011-01-01

    High-quality jet noise spectral data measured at the Aero-Acoustic Propulsion Laboratory (AAPL) at NASA Glenn is used to develop jet noise scaling laws. A FORTRAN algorithm was written that provides detailed spectral prediction of component jet noise at user-specified conditions. The model generates quick estimates of the jet mixing noise and the broadband shock-associated noise (BBSN) in single-stream, axis-symmetric jets within a wide range of nozzle operating conditions. Shock noise is emitted when supersonic jets exit a nozzle at imperfectly expanded conditions. A successful scaling of the BBSN allows for this noise component to be predicted in both convergent and convergent-divergent nozzles. Configurations considered in this study consisted of convergent and convergent- divergent nozzles. Velocity exponents for the jet mixing noise were evaluated as a function of observer angle and jet temperature. Similar intensity laws were developed for the broadband shock-associated noise in supersonic jets. A computer program called sJet was developed that provides a quick estimate of component noise in single-stream jets at a wide range of operating conditions. A number of features have been incorporated into the data bank and subsequent scaling in order to improve jet noise predictions. Measurements have been converted to a lossless format. Set points have been carefully selected to minimize the instability-related noise at small aft angles. Regression parameters have been scrutinized for error bounds at each angle. Screech-related amplification noise has been kept to a minimum to ensure that the velocity exponents for the jet mixing noise remain free of amplifications. A shock-noise-intensity scaling has been developed independent of the nozzle design point. The computer program provides detailed narrow-band spectral predictions for component noise (mixing noise and shock associated noise), as well as the total noise. Although the methodology is confined to single