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Sample records for regular solar occultation

  1. A variational regularization of Abel transform for GPS radio occultation

    Directory of Open Access Journals (Sweden)

    T.-K. Wee

    2018-04-01

    Full Text Available In the Global Positioning System (GPS radio occultation (RO technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical lower troposphere. An alternative to AI is the numerical inversion of the forward Abel transform, which does not incur the integration of error-possessing measurement and thus precludes the error propagation. The variational regularization (VR proposed in this study approximates the inversion of the forward Abel transform by an optimization problem in which the regularized solution describes the measurement as closely as possible within the measurement's considered accuracy. The optimization problem is then solved iteratively by means of the adjoint technique. VR is formulated with error covariance matrices, which permit a rigorous incorporation of prior information on measurement error characteristics and the solution's desired behavior into the regularization. VR holds the control variable in the measurement space to take advantage of the posterior height determination and to negate the measurement error due to the mismodeling of the refractional radius. The advantages of having the solution and the measurement in the same space are elaborated using a purposely corrupted synthetic sounding with a known true solution. The competency of VR relative to AI is validated with a large number of actual RO soundings. The comparison to nearby radiosonde observations shows that VR attains considerably smaller random and systematic errors compared to AI. A noteworthy finding is that in the heights and areas that the measurement bias is supposedly small, VR follows AI very closely in the

  2. A variational regularization of Abel transform for GPS radio occultation

    Science.gov (United States)

    Wee, Tae-Kwon

    2018-04-01

    In the Global Positioning System (GPS) radio occultation (RO) technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI) is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical lower troposphere. An alternative to AI is the numerical inversion of the forward Abel transform, which does not incur the integration of error-possessing measurement and thus precludes the error propagation. The variational regularization (VR) proposed in this study approximates the inversion of the forward Abel transform by an optimization problem in which the regularized solution describes the measurement as closely as possible within the measurement's considered accuracy. The optimization problem is then solved iteratively by means of the adjoint technique. VR is formulated with error covariance matrices, which permit a rigorous incorporation of prior information on measurement error characteristics and the solution's desired behavior into the regularization. VR holds the control variable in the measurement space to take advantage of the posterior height determination and to negate the measurement error due to the mismodeling of the refractional radius. The advantages of having the solution and the measurement in the same space are elaborated using a purposely corrupted synthetic sounding with a known true solution. The competency of VR relative to AI is validated with a large number of actual RO soundings. The comparison to nearby radiosonde observations shows that VR attains considerably smaller random and systematic errors compared to AI. A noteworthy finding is that in the heights and areas that the measurement bias is supposedly small, VR follows AI very closely in the mean refractivity

  3. A variational regularization of Abel transform for GPS radio occultation

    OpenAIRE

    T.-K. Wee

    2018-01-01

    In the Global Positioning System (GPS) radio occultation (RO) technique, the inverse Abel transform of measured bending angle (Abel inversion, hereafter AI) is the standard means of deriving the refractivity. While concise and straightforward to apply, the AI accumulates and propagates the measurement error downward. The measurement error propagation is detrimental to the refractivity in lower altitudes. In particular, it builds up negative refractivity bias in the tropical ...

  4. Precise pointing knowledge for SCIAMACHY solar occultation measurements

    Directory of Open Access Journals (Sweden)

    K. Bramstedt

    2012-11-01

    Full Text Available We present a method to precisely determine the viewing direction for solar occultation instruments from scans over the solar disk. Basic idea is the fit of the maximum intensity during the scan, which corresponds to the center of the solar disk in the scanning direction. We apply this method to the solar occultation measurements of the satellite instrument SCIAMACHY, which scans the Sun in elevation direction. The achieved mean precision is 0.46 mdeg, which corresponds to an tangent height error of about 26 m for individual occultation sequences. The deviation of the derived elevation angle from the geolocation information given along with the product has a seasonal cycle with an amplitude of 2.26 mdeg, which is in tangent height an amplitude of about 127 m. The mean elevation angle offset is −4.41 mdeg (249 m. SCIAMACHY's sun follower device controls the azimuth viewing direction during the occultation measurements. The derived mean azimuth direction has an standard error of 0.65 mdeg, which is about 36 m in horizontal direction at the tangent point. We observe also a seasonal cycle of the azimuth mispointing with an amplitude of 2.3 mdeg, which is slightly increasing with time. The almost constant mean offset is 88 mdeg, which is about 5.0 km horizontal offset at the tangent point.

  5. Digital solar edge tracker for the Halogen Occultation Experiment

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    Mauldin, L. E., III; Moore, A. S.; Stump, C. W.; Mayo, L. S.

    1987-01-01

    The optical and electronic design of the Halogen Occultation Experiment (Haloe) elevation sun sensor is described. The Haloe instrument is a gas-correlation radiometer now being developed at NASA Langley for the Upper Atmosphere Research Satellite. The system uses a Galilean telescope to form a solar image on a linear silicon photodiode array. The array is a self-scanned monolithic CCD. The addresses of both solar edges imaged on the array are used by the control/pointing system to scan the Haloe science instantaneous field of view (IFOV) across the vertical solar diameter during instrument calibration and then to maintain the science IFOV 4 arcmin below the top edge during the science data occultation event. Vertical resolution of 16 arcsec and a radiometric dynamic range of 100 are achieved at the 700-nm operating wavelength. The design provides for loss of individual photodiode elements without loss of angular tracking capability.

  6. Exploring small bodies in the outer solar system with stellar occultations

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    Elliot, Jim L.; Dunham, Edward W.; Olkin, C. B.

    1995-01-01

    Stellar occultation observations probe the atmospheric structure and extinction of outer solar system bodies with a spatial resolution of a few kilometers, and an airborne platform allows the observation of occultations by small bodies that are not visible from fixed telescopes. Results from occultations by Triton, Pluto, and Chiron observed with KAO are discussed, and future directions for this program are presented.

  7. Cassini-VIMS at Jupiter: Solar occultation measurements using Io

    Science.gov (United States)

    Formisano, V.; D'Aversa, E.; Bellucci, G.; Baines, K.H.; Bibring, J.-P.; Brown, R.H.; Buratti, B.J.; Capaccioni, F.; Cerroni, P.; Clark, R.N.; Coradini, A.; Cruikshank, D.P.; Drossart, P.; Jaumann, R.; Langevin, Y.; Matson, D.L.; McCord, T.B.; Mennella, V.; Nelson, R.M.; Nicholson, P.D.; Sicardy, B.; Sotin, Christophe; Chamberlain, M.C.; Hansen, G.; Hibbits, K.; Showalter, M.; Filacchione, G.

    2003-01-01

    We report unusual and somewhat unexpected observations of the jovian satellite Io, showing strong methane absorption bands. These observations were made by the Cassini VIMS experiment during the Jupiter flyby of December/January 2000/2001. The explanation is straightforward: Entering or exiting from Jupiter's shadow during an eclipse, Io is illuminated by solar light which has transited the atmosphere of Jupiter. This light, therefore becomes imprinted with the spectral signature of Jupiter's upper atmosphere, which includes strong atmospheric methane absorption bands. Intercepting solar light refracted by the jovian atmosphere, Io essentially becomes a "miffor" for solar occultation events of Jupiter. The thickness of the layer where refracted solar light is observed is so large (more than 3000 km at Io's orbit), that we can foresee a nearly continuous multi-year period of similar events at Saturn, utilizing the large and bright ring system. During Cassini's 4-year nominal mission, this probing tecnique should reveal information of Saturn's atmosphere over a large range of southern latitudes and times. ?? 2003 Elsevier Inc. All rights reserved.

  8. SOLAR OCCULTATION BY TITAN MEASURED BY CASSINI/UVIS

    Energy Technology Data Exchange (ETDEWEB)

    Capalbo, Fernando J.; Benilan, Yves [Laboratoire Interuniversitaire des Systemes Atmospheriques (LISA), UMR 7583 du CNRS, Universites Paris Est Creteil (UPEC) and Paris Diderot - UPD, 61 avenue du General de Gaulle, 94010 Creteil Cedex (France); Yelle, Roger V.; Koskinen, Tommi T.; Sandel, Bill R. [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States); Holsclaw, Gregory M.; McClintock, William E., E-mail: fernando.capalbo@lisa.u-pec.fr [Laboratory for Atmospheric and Space Physics, University of Colorado, 3665 Discovery Drive, Boulder, CO 80303 (United States)

    2013-04-01

    We present the first published analysis of a solar occultation by Titan's atmosphere measured by the Ultraviolet Imaging Spectrograph on board Cassini. The data were measured during flyby T53 in 2009 April and correspond to latitudes between 21 Degree-Sign and 28 Degree-Sign south. The analysis utilizes the absorption of two solar emission lines (584 A and 630 A) in the ionization continuum of the N{sub 2} absorption cross section and solar emission lines around 1085 A where absorption is due to CH{sub 4}. The measured transmission at these wavelengths provides a direct estimate of the N{sub 2} and CH{sub 4} column densities along the line of sight from the spacecraft to the Sun, which we inverted to obtain the number densities. The high signal-to-noise ratio of the data allowed us to retrieve density profiles in the altitude range 1120-1400 km for nitrogen and 850-1300 km for methane. We find an N{sub 2} scale height of {approx}76 km and a temperature of {approx}153 K. Our results are in general agreement with those from previous work, although there are some differences. Particularly, our profiles agree, considering uncertainties, with the density profiles derived from the Voyager 1 Ultraviolet Spectrograph data, and with in situ measurements by the Ion Neutral Mass Spectrometer with revised calibration.

  9. James Webb Space Telescope Observations of Stellar Occultations by Solar System Bodies and Rings

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    Santos-Sanz, P.; French, R. G.; Pinilla-Alonso, N.; Stansberry, J.; Lin, Z-Y.; Zhang, Z-W.; Vilenius, E.; Mueller, Th.; Ortiz, J. L.; Braga-Ribas, F.; hide

    2016-01-01

    In this paper, we investigate the opportunities provided by the James Webb Space Telescope (JWST) for significant scientific advances in the study of Solar System bodies and rings using stellar occultations. The strengths and weaknesses of the stellar occultation technique are evaluated in light of JWST's unique capabilities. We identify several possible JWST occultation events by minor bodies and rings and evaluate their potential scientific value. These predictions depend critically on accurate a priori knowledge of the orbit of JWST near the Sun–Earth Lagrange point 2 (L2). We also explore the possibility of serendipitous stellar occultations by very small minor bodies as a byproduct of other JWST observing programs. Finally, to optimize the potential scientific return of stellar occultation observations, we identify several characteristics of JWST's orbit and instrumentation that should be taken into account during JWST's development.

  10. Scaled model guidelines for solar coronagraphs' external occulters with an optimized shape.

    Science.gov (United States)

    Landini, Federico; Baccani, Cristian; Schweitzer, Hagen; Asoubar, Daniel; Romoli, Marco; Taccola, Matteo; Focardi, Mauro; Pancrazzi, Maurizio; Fineschi, Silvano

    2017-12-01

    One of the major challenges faced by externally occulted solar coronagraphs is the suppression of the light diffracted by the occulter edge. It is a contribution to the stray light that overwhelms the coronal signal on the focal plane and must be reduced by modifying the geometrical shape of the occulter. There is a rich literature, mostly experimental, on the appropriate choice of the most suitable shape. The problem arises when huge coronagraphs, such as those in formation flight, shall be tested in a laboratory. A recent contribution [Opt. Lett.41, 757 (2016)OPLEDP0146-959210.1364/OL.41.000757] provides the guidelines for scaling the geometry and replicate in the laboratory the flight diffraction pattern as produced by the whole solar disk and a flight occulter but leaves the conclusion on the occulter scale law somehow unjustified. This paper provides the numerical support for validating that conclusion and presents the first-ever simulation of the diffraction behind an occulter with an optimized shape along the optical axis with the solar disk as a source. This paper, together with Opt. Lett.41, 757 (2016)OPLEDP0146-959210.1364/OL.41.000757, aims at constituting a complete guide for scaling the coronagraphs' geometry.

  11. Optimization of the occulter for the Solar Orbiter/METIS coronagraph

    Science.gov (United States)

    Landini, Federico; Vivès, Sébastien; Romoli, Marco; Guillon, Christophe; Pancrazzi, Maurizio; Escolle, Clement; Focardi, Mauro; Antonucci, Ester; Fineschi, Silvano; Naletto, Giampiero; Nicolini, Gianalfredo; Nicolosi, Piergiorgio; Spadaro, Daniele

    2012-09-01

    METIS (Multi Element Telescope for Imaging and Spectroscopy investigation), selected to fly aboard the Solar Orbiter ESA/NASA mission, is conceived to perform imaging (in visible, UV and EUV) and spectroscopy (in EUV) of the solar corona, by means of an integrated instrument suite located on a single optical bench and sharing the same aperture on the satellite heat shield. As every coronagraph, METIS is highly demanding in terms of stray light suppression. Coronagraphs history teaches that a particular attention must be dedicated to the occulter optimization. The METIS occulting system is of particular interest due to its innovative concept. In order to meet the strict thermal requirements of Solar Orbiter, METIS optical design has been optimized by moving the entrance pupil at the level of the external occulter on the S/C thermal shield, thus reducing the size of the external aperture. The scheme is based on an inverted external-occulter (IEO). The IEO consists of a circular aperture on the Solar Orbiter thermal shield. A spherical mirror rejects back the disk-light through the IEO. A breadboard of the occulting assembly (BOA) has been manufactured in order to perform stray light tests in front of two solar simulators (in Marseille, France and in Torino, Italy). A first measurement campaign has been carried on at the Laboratoire d'Astrophysique de Marseille. In this paper we describe the BOA design, the laboratory set-up and the preliminary results.

  12. Hard X-Ray Emission from Partially Occulted Solar Flares: RHESSI Observations in Two Solar Cycles

    Energy Technology Data Exchange (ETDEWEB)

    Effenberger, Frederic; Costa, Fatima Rubio da; Petrosian, Vahé [Department of Physics and KIPAC, Stanford University, Stanford, CA 94305 (United States); Oka, Mitsuo; Saint-Hilaire, Pascal; Krucker, Säm [Space Sciences Laboratory, University of California, Berkeley, CA 94720-7450 (United States); Liu, Wei [Bay Area Environmental Research Institute, 625 2nd Street, Suite 209, Petaluma, CA 94952 (United States); Glesener, Lindsay, E-mail: feffen@stanford.edu, E-mail: frubio@stanford.edu [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States)

    2017-02-01

    Flares close to the solar limb, where the footpoints are occulted, can reveal the spectrum and structure of the coronal looptop source in X-rays. We aim at studying the properties of the corresponding energetic electrons near their acceleration site, without footpoint contamination. To this end, a statistical study of partially occulted flares observed with Reuven Ramaty High-Energy Solar Spectroscopic Imager is presented here, covering a large part of solar cycles 23 and 24. We perform detailed spectra, imaging, and light curve analyses for 116 flares and include contextual observations from SDO and STEREO when available, providing further insights into flare emission that were previously not accessible. We find that most spectra are fitted well with a thermal component plus a broken power-law, non-thermal component. A thin-target kappa distribution model gives satisfactory fits after the addition of a thermal component. X-ray imaging reveals small spatial separation between the thermal and non-thermal components, except for a few flares with a richer coronal source structure. A comprehensive light curve analysis shows a very good correlation between the derivative of the soft X-ray flux (from GOES ) and the hard X-rays for a substantial number of flares, indicative of the Neupert effect. The results confirm that non-thermal particles are accelerated in the corona and estimated timescales support the validity of a thin-target scenario with similar magnitudes of thermal and non-thermal energy fluxes.

  13. Helios-1 Faraday rotation experiment - Results and interpretations of the solar occultations in 1975

    Science.gov (United States)

    Volland, H.; Bird, M. K.; Levy, G. S.; Stelzried, C. T.; Seidel, B. L.

    1977-01-01

    The first of two solar occultations of the satellite Helios-1 in 1975 occurred in April when the satellite's ray path approached the west limb of the sun to a minimum distance of 1.63 solar radii. The second occultation took place in late August/early September when Helios-1 was totally eclipsed by the photosphere. Measurements of the polarization angle of the linearly polarized telemetry signal were performed with automatic tracking polarimeters at the 64 m Goldstone Tracking Station in California and also at the 100 m radio telescope in Effelsberg, West Germany. The coronal Faraday rotation as a function of the solar offset for both occultations is shown in graphs. The theoretical significance of the observations is investigated.

  14. Influence of misalignments on the performance of externally occulted solar coronagraphs. Application to PROBA-3/ASPIICS

    Science.gov (United States)

    Shestov, S. V.; Zhukov, A. N.

    2018-05-01

    Context. The ASPIICS instrument is a novel externally occulted coronagraph that will be launched on board the PROBA-3 mission of the European Space Agency. The external occulter will be placed on one satellite 150 m ahead of the second satellite that will carry an optical instrument. During 6 h out of 19.38 h of orbit, the satellites will fly in a precise (accuracy around a few millimeters) formation, constituting a giant externally occulted coronagraph. The large distance between the external occulter and the primary objective will allow observations of the white-light solar corona starting from extremely low heights 1.1R⊙. Aims: We intend to analyze influence of shifts of the satellites and misalignments of optical elements on the ASPIICS performance in terms of diffracted light. Based on the quantitative influence of misalignments on diffracted light, we provide a recipe for choosing the size of the internal occulter (IO) to achieve a trade-off between the minimal height of observations and sustainability to possible misalignments. Methods: We considered different types of misalignments and analyzed their influence from optical and computational points of view. We implemented a numerical model of the diffracted light and its propagation through the optical system and computed intensities of diffracted light throughout the instrument. Our numerical approach is based on a model from the literature that considered the axisymmetrical case. Here we extend the model to include nonsymmetrical cases and possible misalignments. Results: The numerical computations fully confirm the main properties of the diffracted light that we obtained from semi-analytical consideration. We obtain that relative influences of various misalignments are significantly different. We show that the internal occulter with RIO = 1.694 mm = 1.1R⊙ is large enough to compensate possible misalignments expected to occur in PROBA-3/ASPIICS. Besides that we show that apodizing the edge of the

  15. Theoretical performance of serrated external occulters for solar coronagraphy. Application to ASPIICS

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    Rougeot, R.; Aime, C.

    2018-04-01

    Context. This study is made in the context of the future solar coronagraph ASPIICS of the ESA formation-flying mission Proba-3. Aims: In the context of solar coronagraphy, we provide a comparative study of the theoretical performance of serrated (or toothed) external occulters by varying the number and size of the teeth, which we compare to the sharp-edged and apodized disks. The tooth height is small (a few centimeters), to avoid hindering the observation of the solar corona near the limb. We first analyze the diffraction pattern produced by such occulters. In a second step, we compute the umbra profile by integration over the Sun. Methods: We explored a few methods to compute the diffraction pattern. Two of them were implemented. The first is based on 2D fast Fourier transformation (FFT) routines and a multiplication by the Fresnel filter of the form exp(-iπλzu2). Simple rules were derived and discussed to set the sampling conditions. The Maggi-Rubinowicz representation is then proposed as an alternative method, and is proven to be very efficient for this study. Results: Serrated occulters tend to create a two-level intensity pattern, the inner being the darker, which perfectly matches a previously reported geometrical prediction. The diffraction in this central region is lower by two to four orders of magnitude when compared to the sharp-edged disk. The achieved umbra level at the center ranges from 10-4 to below 10-7, depending on the geometry of the teeth. Conclusions: Our study shows that serrated occulters can achieve a high rejection and can almost reach the performance of the apodized disk when very many teeth are used. We prove that shaped occulters must be preferred to simple disks in solar and stellar coronagraphy.

  16. Retrieval of temperature and pressure using broadband solar occultation: SOFIE approach and results

    Directory of Open Access Journals (Sweden)

    B. T. Marshall

    2011-05-01

    Full Text Available Measurement of atmospheric temperature as a function of pressure, T(P, is key to understanding many atmospheric processes and a prerequisite for retrieving gas mixing ratios and other parameters from solar occultation measurements. This paper gives a brief overview of the solar occultation measurement technique followed by a detailed discussion of the mechanisms that make the measurement sensitive to temperature. Methods for retrieving T(P using both broadband transmittance and refraction are discussed. Investigations using measurements of broadband transmittance in two CO2 absorption bands (the 4.3 and 2.7 μm bands and refractive bending are then presented. These investigations include sensitivity studies, simulated retrieval studies, and examples from SOFIE.

  17. TITAN’S UPPER ATMOSPHERE FROM CASSINI/UVIS SOLAR OCCULTATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Capalbo, Fernando J.; Bénilan, Yves [Laboratoire Inter-Universitaire des Systèmes Atmosphériques (LISA), UMR 7583 du CNRS, Universités Paris Est Créteil (UPEC) and Paris Diderot - UPD, 61 avenue du Général de Gaulle, F-94010, Créteil Cédex (France); Yelle, Roger V.; Koskinen, Tommi T., E-mail: fernando.capalbo@lisa.u-pec.fr [Lunar and Planetary Laboratory, University of Arizona, 1629 E. University Blvd., Tucson, AZ 85721 (United States)

    2015-12-01

    Titan’s atmosphere is composed mainly of molecular nitrogen, methane being the principal trace gas. From the analysis of 8 solar occultations measured by the Extreme Ultraviolet channel of the Ultraviolet Imaging Spectrograph (UVIS) on board Cassini, we derived vertical profiles of N{sub 2} in the range 1100–1600 km and vertical profiles of CH{sub 4} in the range 850–1300 km. The correction of instrument effects and observational effects applied to the data are described. We present CH{sub 4} mole fractions, and average temperatures for the upper atmosphere obtained from the N{sub 2} profiles. The occultations correspond to different times and locations, and an analysis of variability of density and temperature is presented. The temperatures were analyzed as a function of geographical and temporal variables, without finding a clear correlation with any of them, although a trend of decreasing temperature toward the north pole was observed. The globally averaged temperature obtained is (150 ± 1) K. We compared our results from solar occultations with those derived from other UVIS observations, as well as studies performed with other instruments. The observational data we present confirm the atmospheric variability previously observed, add new information to the global picture of Titan’s upper atmosphere composition, variability, and dynamics, and provide new constraints to photochemical models.

  18. Cassini UVIS solar occultations by Saturn's F ring and the detection of collision-produced micron-sized dust

    Science.gov (United States)

    Becker, Tracy M.; Colwell, Joshua E.; Esposito, Larry W.; Attree, Nicholas O.; Murray, Carl D.

    2018-05-01

    We present an analysis of eleven solar occultations by Saturn's F ring observed by the Ultraviolet Imaging Spectrograph (UVIS) on the Cassini spacecraft. In four of the solar occultations we detect an unambiguous signal from diffracted sunlight that adds to the direct solar signal just before or after the occultations occur. The strongest detection was a 10% increase over the direct signal that was enabled by the accidental misalignment of the instrument's pointing. We compare the UVIS data with images of the F ring obtained by the Cassini Imaging Science Subsystem (ISS) and find that in each instance of an unambiguous diffraction signature in the UVIS data, the ISS data shows that there was a recent disturbance in that region of the F ring. Similarly, the ISS images show a quiescent region of the F ring for all solar occultations in which no diffraction signature was detected. We therefore conclude that collisions in the F ring produce a population of small ring particles that can produce a detectable diffraction signal immediately interior or exterior to the F ring. The clearest example of this connection comes from the strong detection of diffracted light in the 2007 solar occultation, when the portion of the F ring that occulted the Sun had suffered a large collisional event, likely with S/2004 S 6, several months prior. This collision was observed in a series of ISS images (Murray et al., 2008). Our spectral analysis of the data shows no significant spectral features in the F ring, indicating that the particles must be at least 0.2 μm in radius. We apply a forward model of the solar occultations, accounting for the effects of diffracted light and the attenuated direct solar signal, to model the observed solar occultation light curves. These models constrain the optical depth, radial width, and particle size distribution of the F ring. We find that when the diffraction signature is present, we can best reproduce the occultation data using a particle population

  19. Titan's Surface Composition from Cassini VIMS Solar Occultation Observations

    Science.gov (United States)

    McCord, Thomas; Hayne, Paul; Sotin, Christophe

    2013-04-01

    Titan's surface is obscured by a thick absorbing and scattering atmosphere, allowing direct observation of the surface within only a few spectral win-dows in the near-infrared, complicating efforts to identify and map geologi-cally important materials using remote sensing IR spectroscopy. We there-fore investigate the atmosphere's infrared transmission with direct measure-ments using Titan's occultation of the Sun as well as Titan's reflectance measured at differing illumination and observation angles observed by Cas-sini's Visual and Infrared Mapping Spectrometer (VIMS). We use two im-portant spectral windows: the 2.7-2.8-mm "double window" and the broad 5-mm window. By estimating atmospheric attenuation within these windows, we seek an empirical correction factor that can be applied to VIMS meas-urements to estimate the true surface reflectance and map inferred composi-tional variations. Applying the empirical corrections, we correct the VIMS data for the viewing geometry-dependent atmospheric effects to derive the 5-µm reflectance and 2.8/2.7-µm reflectance ratio. We then compare the cor-rected reflectances to compounds proposed to exist on Titan's surface. We propose a simple correction to VIMS Titan data to account for atmospheric attenuation and diffuse scattering in the 5-mm and 2.7-2.8 mm windows, generally applicable for airmass water ice for the majority of the low-to-mid latitude area covered by VIMS measurements. Four compositional units are defined and mapped on Titan's surface based on the positions of data clusters in 5-mm vs. 2.8/2.7-mm scatter plots; a simple ternary mixture of H2O, hydrocarbons and CO2 might explain the reflectance properties of these surface units. The vast equatorial "dune seas" are compositionally very homogeneous, perhaps suggesting transport and mixing of particles over very large distances and/or and very consistent formation process and source material. The composi-tional branch characterizing Tui Regio and Hotei Regio is

  20. The effect of solar radio bursts on the GNSS radio occultation signals

    Science.gov (United States)

    Yue, Xinan; Schreiner, William S.; Kuo, Ying-Hwa; Zhao, Biqiang; Wan, Weixing; Ren, Zhipeng; Liu, Libo; Wei, Yong; Lei, Jiuhou; Solomon, Stan; Rocken, Christian

    2013-09-01

    radio burst (SRB) is the radio wave emission after a solar flare, covering a broad frequency range, originated from the Sun's atmosphere. During the SRB occurrence, some specific frequency radio wave could interfere with the Global Navigation Satellite System (GNSS) signals and therefore disturb the received signals. In this study, the low Earth orbit- (LEO-) based high-resolution GNSS radio occultation (RO) signals from multiple satellites (COSMIC, CHAMP, GRACE, SAC-C, Metop-A, and TerraSAR-X) processed in University Corporation for Atmospheric Research (UCAR) were first used to evaluate the effect of SRB on the RO technique. The radio solar telescope network (RSTN) observed radio flux was used to represent SRB occurrence. An extreme case during 6 December 2006 and statistical analysis during April 2006 to September 2012 were studied. The LEO RO signals show frequent loss of lock (LOL), simultaneous decrease on L1 and L2 signal-to-noise ratio (SNR) globally during daytime, small-scale perturbations of SNR, and decreased successful retrieval percentage (SRP) for both ionospheric and atmospheric occultations during SRB occurrence. A potential harmonic band interference was identified. Either decreased data volume or data quality will influence weather prediction, climate study, and space weather monitoring by using RO data during SRB time. Statistically, the SRP of ionospheric and atmospheric occultation retrieval shows ~4% and ~13% decrease, respectively, while the SNR of L1 and L2 show ~5.7% and ~11.7% decrease, respectively. A threshold value of ~1807 SFU of 1415 MHz frequency, which can result in observable GNSS SNR decrease, was derived based on our statistical analysis.

  1. Validation of Earth atmosphere models using solar EUV observations from the CORONAS and PROBA2 satellites in occultation mode

    Science.gov (United States)

    Slemzin, Vladimir; Ulyanov, Artyom; Gaikovich, Konstantin; Kuzin, Sergey; Pertsov, Andrey; Berghmans, David; Dominique, Marie

    2016-02-01

    Aims: Knowledge of properties of the Earth's upper atmosphere is important for predicting the lifetime of low-orbit spacecraft as well as for planning operation of space instruments whose data may be distorted by atmospheric effects. The accuracy of the models commonly used for simulating the structure of the atmosphere is limited by the scarcity of the observations they are based on, so improvement of these models requires validation under different atmospheric conditions. Measurements of the absorption of the solar extreme ultraviolet (EUV) radiation in the upper atmosphere below 500 km by instruments operating on low-Earth orbits (LEO) satellites provide efficient means for such validation as well as for continuous monitoring of the upper atmosphere and for studying its response to the solar and geomagnetic activity. Method: This paper presents results of measurements of the solar EUV radiation in the 17 nm wavelength band made with the SPIRIT and TESIS telescopes on board the CORONAS satellites and the SWAP telescope on board the PROBA2 satellite in the occulted parts of the satellite orbits. The transmittance profiles of the atmosphere at altitudes between 150 and 500 km were derived from different phases of solar activity during solar cycles 23 and 24 in the quiet state of the magnetosphere and during the development of a geomagnetic storm. We developed a mathematical procedure based on the Tikhonov regularization method for solution of ill-posed problems in order to retrieve extinction coefficients from the transmittance profiles. The transmittance profiles derived from the data and the retrieved extinction coefficients are compared with simulations carried out with the NRLMSISE-00 atmosphere model maintained by Naval Research Laboratory (USA) and the DTM-2013 model developed at CNES in the framework of the FP7 project ATMOP. Results: Under quiet and slightly disturbed magnetospheric conditions during high and low solar activity the extinction coefficients

  2. Validation of the Earth atmosphere models using the EUV solar occultation data from the CORONAS and PROBA 2 instruments

    Science.gov (United States)

    Slemzin, Vladimir; Kuzin, Sergey; Berghmans, David; Pertsov, Andrey; Dominique, Marie; Ulyanov, Artyom; Gaikovich, Konstantin

    Absorption in the atmosphere below 500 km results in attenuation of the solar EUV flux, variation of its spectra and distortion of solar images acquired by solar EUV instruments operating on LEO satellites even on solar synchronous orbits. Occultation measurements are important for planning of solar observations from these satellites, and can be used for monitoring the upper atmosphere as well as for studying its response to the solar activity. We present the results of the occultation measurements of the solar EUV radiation obtained by the CORONAS-F/SPIRIT telescope at high solar activity (2002), by the CORONAS-Photon/TESIS telescope at low activity (2009), and by the SWAP telescope and LYRA radiometer onboard the PROBA 2 satellite at moderate activity (2010). The measured attenuation profiles and the retrieved linear extinction coefficients at the heights 200-500 km are compared with simulations by the NRLMSIS-00 and DTM2013 atmospheric models. It was shown that the results of simulations by the DTM2013 model are well agreed with the data of measurements at all stages of solar activity and in presence of the geomagnetic storm, whereas the results of the NRLMSISE-00 model significantly diverge from the measurements, in particular, at high and low activity. The research leading to these results has received funding from the European Union’s Seventh Programme for Research, Technological Development and Demonstration under Grant Agreement “eHeroes” (project No.284461, www.eheroes.eu).

  3. Modeling of the Enceladus water vapor jets for interpreting UVIS star and solar occultation observations

    Science.gov (United States)

    Portyankina, Ganna; Esposito, Larry W.; Aye, Klaus-Michael; Hansen, Candice J.

    2015-11-01

    One of the most spectacular discoveries of the Cassini mission is jets emitting from the southern pole of Saturn’s moon Enceladus. The composition of the jets is water vapor and salty ice grains with traces of organic compounds. Jets, merging into a wide plume at a distance, are observed by multiple instruments on Cassini. Recent observations of the visible dust plume by the Cassini Imaging Science Subsystem (ISS) identified as many as 98 jet sources located along “tiger stripes” [Porco et al. 2014]. There is a recent controversy on the question if some of these jets are “optical illusion” caused by geometrical overlap of continuous source eruptions along the “tiger stripes” in the field of view of ISS [Spitale et al. 2015]. The Cassini’s Ultraviolet Imaging Spectrograph (UVIS) observed occultations of several stars and the Sun by the water vapor plume of Enceladus. During the solar occultation separate collimated gas jets were detected inside the background plume [Hansen et al., 2006 and 2011]. These observations directly provide data about water vapor column densities along the line of sight of the UVIS instrument and could help distinguish between the presence of only localized or also continuous sources. We use Monte Carlo simulations and Direct Simulation Monte Carlo (DSMC) to model the plume of Enceladus with multiple (or continuous) jet sources. The models account for molecular collisions, gravitational and Coriolis forces. The models result in the 3-D distribution of water vapor density and surface deposition patterns. Comparison between the simulation results and column densities derived from UVIS observations provide constraints on the physical characteristics of the plume and jets. The specific geometry of the UVIS observations helps to estimate the production rates and velocity distribution of the water molecules emitted by the individual jets.Hansen, C. J. et al., Science 311:1422-1425 (2006); Hansen, C. J. et al, GRL 38:L11202 (2011

  4. Low-Cost Small Satellite Atmospheric Rotating Solar Occultation Imager (ROI)

    Data.gov (United States)

    National Aeronautics and Space Administration — Utilizing a unique, new occultation technique involving imaging, the ROI concept will meet or exceed the quality of SAGE measurements at a small fraction of the...

  5. Water vapour and methane coupling in the stratosphere observed using SCIAMACHY solar occultation measurements

    Directory of Open Access Journals (Sweden)

    S. Noël

    2018-04-01

    Full Text Available An improved stratospheric water vapour data set has been retrieved from SCIAMACHY/ENVISAT solar occultation measurements. It is similar to that successfully applied to methane and carbon dioxide. There is now a consistent set of data products for the three constituents covering the altitudes 17–45 km, the latitude range between about 50 and 70° N, and the period August 2002 to April 2012. The new water vapour concentration profiles agree with collocated results from ACE-FTS and MLS/Aura to within  ∼  5 %. A significant positive linear change in water vapour for the time 2003–2011 is observed at lower stratospheric altitudes with a value of about 0.015 ± 0.008 ppmv year−1 around 17 km. Between 30 and 37 km the changes become significantly negative (about −0.01 ± 0.008 ppmv year−1; all errors are 2σ values. The combined analysis of the SCIAMACHY methane and water vapour time series shows the expected anti-correlation between stratospheric methane and water vapour and a clear temporal variation related to the Quasi-Biennial Oscillation (QBO. Above about 20 km most of the additional water vapour is attributed to the oxidation of methane. In addition short-term fluctuations and longer-term variations on a timescale of 5–6 years are observed. The SCIAMACHY data confirm that at lower altitudes the amount of water vapour and methane are transported from the tropics to higher latitudes via the shallow branch of the Brewer–Dobson circulation.

  6. Poster 7: Could PAH or HAC explain the Titan's stratosphere absorption around 3.4 µm revealed by solar occultations?

    Science.gov (United States)

    Cordier, Daniel; Cours, Thibaud; Rey, Michael; Maltagliati, Luca; Seignovert, Benoit; Biennier, Ludovic

    2016-06-01

    In 2006, during Cassini's 10th flyby of Titan (T10), Bellucci et al. (2009) observed a solar occultation by Titan's atmosphere through the solar port of the Cassini/VIMS instrument. These authors noticed the existence of an unexplained additional absorption superimposed to the CH4 3.3 µm band. Because they were unable to model this absorption with gases, they attributed this intriguing feature to the signature of solid state organic components. Kim et al. (2011) revisited the data collected by Bellucci et al. (2009) and they considered the possible contribution of aerosols formed by hydrocarbon ices. They specifically took into account C2H6, CH4, CH3CN, C5H12 and C6H12 ices. More recently, Maltagliati et al. (2015) analyzed a set of four VIMS solar occultations, corresponding to flybys performed between January 2006 and September 2011 at different latitudes. They confirmed the presence of the 3.3 µm absorption in all occultations and underlined the possible importance of gaseous ethane, which has a strong plateau of absorption lines in that wavelength range.In this work, we show that neither hydrocarbon ices nor molecular C2H6 cannot satisfactorily explain the observed absorption. Our simulations speak in favor of an absorption due to the presence of PAH molecules or HAC in the stratosphere of Titan. PAH have been already considered by Lopes-Puertas et al. (2013) at altitudes larger than ˜900 km and tentatively identified in the stratosphere by Maltagliati et al. (2015); PAH and HAC are good candidates for Titan's aerosols precursors.

  7. Solar occultation images analysis using Zernike polynomials ­— an ALTIUS imaging spectrometer application

    Science.gov (United States)

    Dekemper, Emmanuel; Fussen, Didier; Loodts, Nicolas; Neefs, Eddy

    The ALTIUS (Atmospheric Limb Tracker for the Investigation of the Upcoming Stratosphere) instrument is a major project of the Belgian Institute for Space Aeronomy (BIRA-IASB) in Brussels, Belgium. It has been designed to profit from the benefits of the limb scattering ge-ometry (vertical resolution, global coverage,...), while providing better accuracy on the tangent height knowledge than classical "knee" methods used by scanning spectrometers. The optical concept is based on 3 AOTF's (UV-Vis-NIR) responsible for the instantaneous spectral filtering of the incoming image (complete FOV larger than 100km x 100km at tangent point), ranging from 250nm to 1800nm, with a moderate resolution of a few nm and a typical acquisition time of 1-10s per image. While the primary goal of the instrument is the measurement of ozone with a good vertical resolution, the ability to record full images of the limb can lead to other applications, like solar occultations. With a pixel FOV of 200rad, the full high-sun image is formed of 45x45 pixels, which is sufficient for pattern recognition using moments analysis for instance. The Zernike polynomials form a complete othogonal set of functions over the unit circle. It is well suited for images showing circular shape. Any such image can then be decomposed into a finite set of weighted polynomials, the weighting is called the moments. Due to atmospheric refraction, the sun shape is modified during apparent sunsets and sunrises. The sun appears more flattened which leads to a modification of its zernike moment description. A link between the pressure or the temperature profile (equivalent to air density through the perfect gas law and the hydrostatic equation) and the Zernike moments of a given image can then be made and used to retrieve these atmospheric parameters, with the advantage that the whole sun is used and not only central or edge pixels. Some retrievals will be performed for different conditions and the feasibility of the method

  8. Signal noise ratio analysis and on-orbit performance estimation of a solar occultation Fourier transform spectrometer

    Science.gov (United States)

    Li, Bicen; Xu, Pengmei; Hou, Lizhou; Wang, Caiqin

    2017-10-01

    Taking the advantages of high spectral resolution, high sensitivity and wide spectral coverage, space borne Fourier transform infrared spectrometer (FTS) plays more and more important role in atmospheric composition sounding. The combination of solar occultation and FTS technique improves the sensitivity of instrument. To achieve both high spectral resolution and high signal to noise ratio (SNR), reasonable allocation and optimization for instrument parameters are the foundation and difficulty. The solar occultation FTS (SOFTS) is a high spectral resolution (0.03 cm-1) FTS operating from 2.4 to 13.3 μm (750-4100cm-1), which will determine the altitude profile information of typical 10-100km for temperature, pressure, and the volume mixing ratios for several dozens of atmospheric compositions. As key performance of SOFTS, SNR is crucially important to high accuracy retrieval of atmospheric composition, which is required to be no less than 100:1 at the radiance of 5800K blackbody. Based on the study of various parameters and its interacting principle, according to interference theory and operation principle of time modulated FTS, a simulation model of FTS SNR has been built, which considers satellite orbit, spectral radiometric features of sun and atmospheric composition, optical system, interferometer and its control system, measurement duration, detector sensitivity, noise of detector and electronic system and so on. According to the testing results of SNR at the illuminating of 1000 blackbody, the on-orbit SNR performance of SOFTS is estimated, which can meet the mission requirement.

  9. Time delay occultation data of the Helios spacecraft for probing the electron density distribution in the solar corona

    Science.gov (United States)

    Edenhofer, P.; Lueneburg, E.; Esposito, P. B.; Martin, W. L.; Zygielbaum, A. I.; Hansen, R. T.; Hansen, S. F.

    1978-01-01

    S-band time delay measurements were collected from the spacecraft Helios A and B during three solar occultations in 1975/76 within heliocentric distances of about 3 and 215 earth radius in terms of range, Doppler frequency shift, and electron content. Characteristic features of measurement and data processing are described. Typical data sets are discussed to probe the electron density distribution near the sun (west and east limb as well) including the outer and extended corona. Steady-state and dynamical aspects of the solar corona are presented and compared with earth-bound-K-coronagraph measurements. Using a weighted least squares estimation, parameters of an average coronal electron density profile are derived in a preliminary analysis to yield electron densities at r = 3, 65, 215 earth radius. Transient phenomena are discussed and a velocity of propagation v is nearly equal to 900 km/s is determined for plasma ejecta from a solar flare observed during an extraordinary set of Helios B electron content measurements.

  10. A regularization method for extrapolation of solar potential magnetic fields

    Science.gov (United States)

    Gary, G. A.; Musielak, Z. E.

    1992-01-01

    The mathematical basis of a Tikhonov regularization method for extrapolating the chromospheric-coronal magnetic field using photospheric vector magnetograms is discussed. The basic techniques show that the Cauchy initial value problem can be formulated for potential magnetic fields. The potential field analysis considers a set of linear, elliptic partial differential equations. It is found that, by introducing an appropriate smoothing of the initial data of the Cauchy potential problem, an approximate Fourier integral solution is found, and an upper bound to the error in the solution is derived. This specific regularization technique, which is a function of magnetograph measurement sensitivities, provides a method to extrapolate the potential magnetic field above an active region into the chromosphere and low corona.

  11. Faraday rotation fluctutation spectra observed during solar occultation of the Helios spacecraft

    Science.gov (United States)

    Andreev, V.; Efimov, A. I.; Samoznaev, L.; Bird, M. K.

    1995-01-01

    Faraday rotation (FR) measurements using linearly polarized radio signals from the two Helios spacecraft were carried out during the period from 1975 to 1984. This paper presents the results of a spectral analysis of the Helios S-band FR fluctuations observed at heliocentric distances from 2.6 to 15 solar radii during the superior conjunctions 1975-1983. The mean intensity of the FR fluctuations does not exceed the noise level for solar offsets greater than ca. 15 solar radii. The rms FR fluctuation amplitude increases rapidly as the radio ray path approaches the Sun, varying according to a power law (exponent: 2.85 +/- 0.15) at solar distances 4-12 solar radii. At distances inside 4 solar radii the increase is even steeper (exponent: 5.6 +/- 0.2). The equivalent two-dimensional FR fluctuation spectrum is well modeled by a single power-law over the frequency range from 5 to 50 mHz. For heliocentric distances larger than 4 solar radii the spectral index varies between 1.1 and 1.6 with a mean value of 1.4 +/- 0.2, corresponding to a 3-D spectral index p = 2.4. FR fluctuations thus display a somwhat lower spectral index compared with phase and amplitude fluctuations. Surprisingly high values of the spectral index were found for measurements inside 4 solar radii (p = 2.9 +/- 0.2). This may arise from the increasingly dominant effect of the magnetic field on radio wave propagation at small solar offsets. Finally, a quasiperiodic component, believed to be associated with Alfven waves, was discovered in some (but not all!) fluctuation spectra observed simultaneously at two ground stations. Characteristic periods and bulk velocities of this component were 240 +/- 30 sec and 300 +/- 60 km/s, respectively.

  12. Validation of SCIAMACHY limb NO2 profiles using solar occultation measurements

    Directory of Open Access Journals (Sweden)

    H. Bovensmann

    2012-05-01

    Full Text Available The increasing amounts of reactive nitrogen in the stratosphere necessitate accurate global measurements of stratospheric nitrogen dioxide (NO2. Over the past decade, the SCIAMACHY (SCanning Imaging Absorption spectroMeter for Atmospheric CHartographY instrument on ENVISAT (European Environmental Satellite has been providing global coverage of stratospheric NO2 every 6 days. In this study, the vertical distributions of NO2 retrieved from SCIAMACHY limb measurements of the scattered solar light are validated by comparison with NO2 products from three different satellite instruments (SAGE II, HALOE and ACE-FTS. The retrieval algorithm based on the information operator approach is discussed, and the sensitivity of the SCIAMACHY NO2 limb retrievals is investigated. The photochemical corrections needed to make this validation feasible, and the chosen collocation criteria are described. For each instrument, a time period of two years is analyzed with several hundreds of collocation pairs for each year. As NO2 is highly variable, the comparisons are performed for five latitudinal bins and four seasons. In the 20 to 40 km altitude range, mean relative differences between SCIAMACHY and other instruments are found to be typically within 20 to 30%. The mean partial NO2 columns in this altitude range agree typically within 15% (both global monthly and zonal annual means. Larger differences are seen for SAGE II comparisons, which is consistent with the results presented by other authors. For SAGE II and ACE-FTS, the observed differences can be partially attributed to the diurnal effect error.

  13. Dependence of regular background noise of VLF radiation and thunder-storm activity on solar wind proton density

    International Nuclear Information System (INIS)

    Sobolev, A.V.; Kozlov, V.I.

    1997-01-01

    Correlation of the intensity of slowly changing regular background noise within 9.7 kHz frequency in Yakutsk (L = 3) and of the solar wind density protons was determined. This result explains the reverse dependence of the intensity of the regular background noise on the solar activity, 27-day frequency, increase before and following geomagnetic storms, absence of relation with K p index of geomagnetic activity. Conclusion is made that growth of density of the solar wind protons results in increase of the regular background noise and thunderstorm activity

  14. First results from stellar occultations in the "GAIA era"

    Science.gov (United States)

    Benedetti-Rossi, G.; Vieira-Martins, R.; Sicardy, B.

    2017-09-01

    Stellar occultation is a powerful technique to study distant solar system bodies. It allows high angular resolution of the occulting body from the analysis of a light curve acquired with high temporal resolution with uncertainties comparable as probes. In the "GAIA era", stellar occultations is now able to obtain even more impressive results such as the presence of atmosphere, rings and topographic features.

  15. Efficient Regular Perovskite Solar Cells Based on Pristine [70]Fullerene as Electron-Selective Contact.

    Science.gov (United States)

    Collavini, Silvia; Kosta, Ivet; Völker, Sebastian F; Cabanero, German; Grande, Hans J; Tena-Zaera, Ramón; Delgado, Juan Luis

    2016-06-08

    [70]Fullerene is presented as an efficient alternative electron-selective contact (ESC) for regular-architecture perovskite solar cells (PSCs). A smart and simple, well-described solution processing protocol for the preparation of [70]- and [60]fullerene-based solar cells, namely the fullerene saturation approach (FSA), allowed us to obtain similar power conversion efficiencies for both fullerene materials (i.e., 10.4 and 11.4 % for [70]- and [60]fullerene-based devices, respectively). Importantly, despite the low electron mobility and significant visible-light absorption of [70]fullerene, the presented protocol allows the employment of [70]fullerene as an efficient ESC. The [70]fullerene film thickness and its solubility in the perovskite processing solutions are crucial parameters, which can be controlled by the use of this simple solution processing protocol. The damage to the [70]fullerene film through dissolution during the perovskite deposition is avoided through the saturation of the perovskite processing solution with [70]fullerene. Additionally, this fullerene-saturation strategy improves the performance of the perovskite film significantly and enhances the power conversion efficiency of solar cells based on different ESCs (i.e., [60]fullerene, [70]fullerene, and TiO2 ). Therefore, this universal solution processing protocol widens the opportunities for the further development of PSCs. © 2016 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

  16. Occultations for probing atmosphere and climate

    CERN Document Server

    Foelsche, Ulrich; Steiner, Andrea

    2004-01-01

    Use of occultation methodology for observing the Earth's atmosphere and climate has become so broad as to comprise solar, lunar, stellar, navigation and satellite­ crosslink occultation methods. The atmospheric parameters obtained extend from the fundamental variables temperature, density, pressure, water vapor, and ozone via a multitude of trace gas species to particulate species such as aerosols and cloud liquid water. Ionospheric electron density is sensed as well. The methods all share the key properties of self-calibration, high accuracy and vertical resolution, global coverage, and (if using radio signals) all-weather capability. Occultation data are thus of high value in a wide range of fields including climate monitoring and research, atmospheric physics and chemistry, operational meteorology, and other fields such as space weather and planetary science. This wide area of variants and uses of the occultation method has led to a diversi­ fication of the occultation-related scientific community into a...

  17. Optical performance of the New Worlds Occulter

    Science.gov (United States)

    Arenberg, Jonathan W.; Lo, Amy S.; Glassman, Tiffany M.; Cash, Webster

    2007-04-01

    The New Worlds Observer (NWO) is a multiple spacecraft mission that is capable of detecting and characterizing extra-solar planets and planetary systems. NWO consists of an external occulter and a generic space telescope, flying in tandem. The external occulter has specific requirements on its shape and size, while the telescope needs no special modification beyond that required to do high-quality astrophysical observations. The occulter is a petal-shaped, opaque screen that creates a high-suppression shadow large enough to accommodate the telescope. This article reports on the optical performance of the novel New Worlds occulter design. It also introduces two new aspects of its optical performance which enhance the detectability of extra-solar planets. We also include a brief discussion of the buildability and the tolerances of the occulter. It is also shown that an occulter design can be found for any set of science requirements. We show that NWO is a viable mission concept for the study of extra-solar planets. To cite this article: J.W. Arenberg et al., C. R. Physique 8 (2007).

  18. Contrary interfacial exciton dissociation at metal/organic interface in regular and reverse configuration organic solar cells

    Energy Technology Data Exchange (ETDEWEB)

    Wu, Bo; Wu, Zhenghui; Tam, Hoi Lam; Zhu, Furong, E-mail: frzhu@hkbu.edu.hk [Department of Physics, Institute of Advanced Materials, and Institute of Research and Continuing Education (Shenzhen), Hong Kong Baptist University, 224 Waterloo Road, Kowloon Tong, NT (Hong Kong)

    2014-09-08

    An opposite interfacial exciton dissociation behavior at the metal (Al)/organic cathode interface in regular and inverted organic solar cells (OSCs) was analyzed using transient photocurrent measurements. It is found that Al/organic contact in regular OSCs, made with the blend layer of poly[[4,8-bis[(2-ethylhexyl)oxy]benzo[1,2-b:4,5-b′]dithiophene-2,6-diyl] -[3-fluoro-2-[(2-ethylhexyl)carbonyl]thieno[3,4-b]-thiophenediyl

  19. REGULARITY OF THE NORTH–SOUTH ASYMMETRY OF SOLAR ACTIVITY: REVISITED

    International Nuclear Information System (INIS)

    Zhang, J.; Feng, W.

    2015-01-01

    Extended time series of Solar Activity Indices (ESAI) extended the Greenwich series of sunspot area from the year 1874 back to 1821. The ESAI's yearly sunspot area in the northern and southern hemispheres from 1821 to 2013 is utilized to investigate characteristics of the north–south hemispherical asymmetry of sunspot activity. Periodical behavior of about 12 solar cycles is also confirmed from the ESAI data set to exist in dominant hemispheres, linear regression lines of yearly asymmetry values, and cumulative counts of yearly sunspot areas in the hemispheres for solar cycles. The period is also inferred to appear in both the cumulative difference in the yearly sunspot areas in the hemispheres over the entire time interval and in its statistical Student's t-test. The hemispherical bias of sunspot activity should be regarded as an impossible stochastic phenomenon over a long time period

  20. Long-term Regularities in Distribution of Global Solar and Interplanetary Magnetic Fields

    Czech Academy of Sciences Publication Activity Database

    Ambrož, Pavel

    2013-01-01

    Roč. 37, č. 2 (2013), s. 637-642 ISSN 1845-8319. [Hvar Astrophysical Colloquium /12./. Hvar, 03.09.2012-07.09.2012] R&D Projects: GA AV ČR IAA300030808 Institutional support: RVO:67985815 Keywords : interplanetary magnetic field * solar wind Subject RIV: BN - Astronomy, Celestial Mechanics, Astrophysics

  1. Some problems concerning the regularities in the development of the latitudinal distribution of solar magnetic fields

    International Nuclear Information System (INIS)

    Bumba, V.; Hejna, L.

    1988-01-01

    From the comparison of several modes of time development of the latitudinal distribution of solar magnetic fields, obtained by different authors using different basic observational material and different methods, the following results were obtained: At high solar latitudes (|φ|> or ∼ 40deg) all distributions agree irrespective of the method of construction. In zones of activity around the solar equator, there is a qualitatively good but quantitatively poor agreement of the integrated, directly observed fields (from Mt. Wilson Observatory) and of the highly integrated fields derived from Hα synoptic charts. The mode of field distribution at high latitudes, more uniform and unipolar, is probably different from the field distribution at low latitudes where the more concentrated leading polarity occupies practically the same area as the less concentrated following polarity fields, if they are highly integrated. The large difference between Makarov's distribution and other modes of distribution seems to be natural if we take the method of construction into account, and very probably represents its close relationship with the smaller magnetic field elements connected with newer activity, while the other types of distribution demonstrate larger-scale, redistributed, older fields. The areas covered by the positive and negative polarities on the whole Sun during the investigated one and a half solar cycles (No 20 and 21) are practically equal. (author). 5 figs., 10 refs

  2. Measurement of stellar occultations

    Science.gov (United States)

    Eberle, Andreas

    2008-09-01

    Whenever an asteroid occults a star, we have the opportunity to study that asteroid in great detail. As frequently shown in the past, amateur astronomers1 have the necessary equipment to measure such events successfully2. Combined with the dense net of amateur observatories and online coordination tools3 for movable stations, they can create fine grids to detect even small bodies. The analysis of these events gives us the possibility to receive high precision astrometry data, to determine the asteroids size and shape (and therefore its albedo), and even to collect information on the star itself.4 While usually a set of several light curves is required to do so, a single recording5 of (10734) Wieck's occultation of HIP 22157 on 2008 Feb 08 was sufficient to retrieve the necessary data6. 1 Observation campaigns are organized by the International Occultation Timing Association (IOTA), http://www.iota-es.de/ 2 for results see e.g. euraster.net by E. Frappa, http://www.euraster.net/ 3 Occult Watcher by H. Pavlov, http://www.hristopavlov.net/OccultWatcher/OccultWatcher.html 4 see K. Miyashita's analysis of the observation of the occultation of TYC 1886-01206-1 by Kalliope and Linus, http://www005.upp.so-net.ne.jp/k miyash/occ02/kalliope/doublestar en.html 5 recording obtained by H. Michels, MPC Station Code 240 6 using Limovie by K. Miyashita

  3. Zinc oxide modified with benzylphosphonic acids as transparent electrodes in regular and inverted organic solar cell structures

    Energy Technology Data Exchange (ETDEWEB)

    Lange, Ilja; Reiter, Sina; Kniepert, Juliane; Piersimoni, Fortunato; Brenner, Thomas; Neher, Dieter, E-mail: neher@uni-potsdam.de [Institute of Physics and Astronomy, University of Potsdam, Karl-Liebknecht-Strasse 24-25, 14476 Potsdam (Germany); Pätzel, Michael; Hildebrandt, Jana; Hecht, Stefan [Department of Chemistry and IRIS Adlershof, Humboldt-Universität zu Berlin, Brook-Taylor-Str. 2, 12489 Berlin (Germany)

    2015-03-16

    An approach is presented to modify the work function of solution-processed sol-gel derived zinc oxide (ZnO) over an exceptionally wide range of more than 2.3 eV. This approach relies on the formation of dense and homogeneous self-assembled monolayers based on phosphonic acids with different dipole moments. This allows us to apply ZnO as charge selective bottom electrodes in either regular or inverted solar cell structures, using poly(3-hexylthiophene):phenyl-C71-butyric acid methyl ester as the active layer. These devices compete with or even surpass the performance of the reference on indium tin oxide/poly(3,4-ethylenedioxythiophene) polystyrene sulfonate. Our findings highlight the potential of properly modified ZnO as electron or hole extracting electrodes in hybrid optoelectronic devices.

  4. A visibility-based approach using regularization for imaging-spectroscopy in solar X-ray astronomy

    Energy Technology Data Exchange (ETDEWEB)

    Prato, M; Massone, A M; Piana, M [CNR - INFM LAMIA, Via Dodecaneso 33 1-16146 Genova (Italy); Emslie, A G [Department of Physics, Oklahoma State University, Stillwater, OK 74078 (United States); Hurford, G J [Space Sciences Laboratory, University of California at Berkeley, 8 Gauss Way, Berkeley, CA 94720-7450 (United States); Kontar, E P [Department of Physics and Astronomy, The University, Glasgow G12 8QQ, Scotland (United Kingdom); Schwartz, R A [CUA - Catholic University and LSSP at NASA Goddard Space Flight Center, code 671.1 Greenbelt, MD 20771 (United States)], E-mail: massone@ge.infm.it

    2008-11-01

    The Reuven Ramaty High-Energy Solar Spectroscopic Imager (RHESSI) is a nine-collimators satellite detecting X-rays and {gamma}-rays emitted by the Sun during flares. As the spacecraft rotates, imaging information is encoded as rapid time-variations of the detected flux. We recently proposed a method for the construction of electron flux maps at different electron energies from sets of count visibilities (i.e., direct, calibrated measurements of specific Fourier components of the source spatial structure) measured by RHESSI. The method requires the application of regularized inversion for the synthesis of electron visibility spectra and of imaging techniques for the reconstruction of two-dimensional electron flux maps. The method, already tested on real events registered by RHESSI, is validated in this paper by means of simulated realistic data.

  5. David Levy's Guide to Eclipses, Transits, and Occultations

    Science.gov (United States)

    Levy, David H.

    2010-08-01

    Introduction; Part I. The Magic and History of Eclipses: 1. Shakespeare, King Lear, and the Great Eclipse of 1605; 2. Three centuries later: Einstein, relativity, and the solar eclipse of 1919; 3. What causes solar and lunar eclipses; Part II. Observing Solar Eclipses: 4. Safety considerations; 5. What to expect during a partial eclipse; 6. Annular eclipses and what to see in them; 7. Total eclipse of the Sun: introduction to the magic; 8. The onset: temperature drop, Baily's Beads, Diamond Ring; 9. Totality: Corona, Prominences, Chromosphere, and surrounding area; 10. Photographing and imaging a solar eclipse; Part III. Observing Lunar Eclipses: 11. Don't forget the penumbral eclipses!; 12. Partial lunar eclipses; 13. Total lunar eclipses; 14. Photographing and imaging lunar eclipses; Part IV. Occultations: 15. When the Moon occults a star; Part V. Transits: 16. When planets cross the Sun; Part VI. My Favorite Eclipses: 17. A personal canon of eclipses, occultations, and transits I have seen; Appendices; Index.

  6. Results from occultations by minor planets

    International Nuclear Information System (INIS)

    Taylor, G.E.

    1982-01-01

    Since the minor planets are believed to consist of primordial matter dating from the time of the formation of the solar system there is great interest in determining their composition. It is therefore necessary to calculate their densities, for which we need accurate masses and sizes. On the rare occasions when a minor planet occults a star, timed observations of the event from a number of observing sites enable an accurate size of the minor planet to be determined. (Auth.)

  7. Occult spinal dysraphism

    African Journals Online (AJOL)

    paediatricians, paediatric neurosurgeons, urologists, orthopaedic surgeons, occupational ... Occult spinal dysraphism refers to a diverse group of congenital abnormalities resulting from varying degrees of disordered neuro- embryogenesis. Several terms have .... can image the whole spine. T1-weighted sagittal and axial ...

  8. Occult Macular Dystrophy

    Directory of Open Access Journals (Sweden)

    Işıl Sayman Muslubaş

    2016-04-01

    Full Text Available Occult macular dystrophy is an inherited macular dystrophy characterized by a progressive decline of bilateral visual acuity with normal fundus appearance, fluorescein angiogram and full-field electroretinogram. This case report presents a 20-year-old female patient with bilateral progressive decline of visual acuity for six years. Her visual acuity was 3-4/10 in both eyes. Anterior segment and fundus examination, fluorescein angiogram and full-field electroretinogram were normal. She could read all Ishihara pseudoisochromatic plates. Fundus autofluorescence imaging was normal. There was a mild central hyporeflectance on fundus infrared reflectance imaging in both eyes. Reduced foveal thickness and alterations of the photoreceptor inner and outer segment junction were observed by optical coherence tomography in both eyes. Central scotoma was also found by microperimetry and reduced central response was revealed by multifocal electroretinogram in both eyes. These findings are consistent with the clinical characteristics of occult macular dystrophy

  9. Occult carbon monoxide poisoning.

    Science.gov (United States)

    Kirkpatrick, J N

    1987-01-01

    A syndrome of headache, fatigue, dizziness, paresthesias, chest pain, palpitations and visual disturbances was associated with chronic occult carbon monoxide exposure in 26 patients in a primary care setting. A causal association was supported by finding a source of carbon monoxide in a patient's home, workplace or vehicle; results of screening tests that ruled out other illnesses; an abnormally high carboxyhemoglobin level in 11 of 14 patients tested, and abatement or resolution of symptoms when the source of carbon monoxide was removed. Exposed household pets provided an important clue to the diagnosis in some cases. Recurrent occult carbon monoxide poisoning may be a frequently overlooked cause of persistent or recurrent headache, fatigue, dizziness, paresthesias, abdominal pain, diarrhea and unusual spells.

  10. Occult Carbon Monoxide Poisoning

    OpenAIRE

    Kirkpatrick, John N.

    1987-01-01

    A syndrome of headache, fatigue, dizziness, paresthesias, chest pain, palpitations and visual disturbances was associated with chronic occult carbon monoxide exposure in 26 patients in a primary care setting. A causal association was supported by finding a source of carbon monoxide in a patient's home, workplace or vehicle; results of screening tests that ruled out other illnesses; an abnormally high carboxyhemoglobin level in 11 of 14 patients tested, and abatement or resolution of symptoms ...

  11. Occult pneumothorax, revisited

    OpenAIRE

    Mangar Devanand; Abdelmalak Hany; Omar Hesham R; Rashad Rania; Helal Engy; Camporesi Enrico M

    2010-01-01

    Abstract Pneumothorax is a recognized cause of preventable death following chest wall trauma where a simple intervention can be life saving. In cases of trauma patients where cervical spine immobilization is mandatory, supine AP chest radiograph is the most practical initial study. It is however not as sensitive as CT chest for early detection of a pneumothorax. "Occult" pneumothorax is an accepted definition of an existing but usually a clinically and radiologically silent disturbance that i...

  12. GAMBARAN RADIOLOGIS PADA OCCULT PNEUMOTHORAKS

    Directory of Open Access Journals (Sweden)

    Putu Aditha Satya Putra

    2013-02-01

    Full Text Available Pneumothorax is a recognized cause of death in chest wall trauma. Radiological examination is the key factor to establish the existence of a pneumothorax. Occult pneumothorax is pneumothorax that undiagnosed clinically and with thoracic x-ray, but it can be tolerated while other more urgent trauma. Occult pneumothorax can be detected by CT (Computed tomography. Occult pneumothorax may progress to tension pneumothorax in certain circumstances. Missing in diagnosed pneumothorax will cause death. This literature will discuss radiological examination for diagnosing, early detection, and management of occult pneumothorax. If thoracic x-ray examination did not reveal the occult pneumothorax, it can be dangerous if existence of pneumothorax was not known. In this case, the examination of thoracic CT-Scan is gold standard for determining the presence of occult pneumothorax and can provide appropriate care.

  13. Characterization and evolution of distant planetary atmospheres using stellar occultations

    Science.gov (United States)

    Young, L. A.

    2008-09-01

    Ground-based or near-Earth (e.g., HST) stellar occultations of every atmosphere in our solar system has been observed: Venus, Mars, Jupiter, Saturn, Titan, Uranus, Neptune, Triton, and Pluto [1]. These observations probe the atmospheres at roughly 0.1 to 100 microbar. I will talk about three aspects of stellar occultations: one-dimensional vertical profiles of the atmosphere, two- or three-dimensional atmospheric states, and the time evolution of atmosphere. In all three, I will draw on recent observations, with an emphasis on Pluto. Occultations are particularly important for the study of Pluto's atmosphere, which is impossible to study with imaging, and extremely difficult to study with spectroscopy. It was discovered by stellar occultation in 1988 [2]. No subsequent Pluto occultations were observed until two events in 2002 [3]. Pluto is now crossing the galactic plane, and there have been several additional occultations observed since 2006. These include a high signal-to-noise observation from the Anglo Australian Observatory in 2006 [4] (Fig 1), densely spaced visible and infrared observations of Pluto's upper atmosphere from telescopes in the US and Mexico in March, 2007 [5] (Fig. 2), and a dualwavelength central flash observation from Mt. John in July, 2007 [6] (Fig 3). The flux from a star occulted by an atmosphere diminishes primarily due to the increase in refraction with depth in the atmosphere, defocusing the starlight, although absorption and tangential focusing can also contribute. Because the atmospheric density, to first order, follows an exponential, it is feasible to derive a characteristic pressure and temperature from isothermal fits to even low-quality occultation light curves. Higher quality light curves allow fits with more flexible models, or light curve inversions that derive temperatures limited by the resolution of the data. These allow the derivation of one-dimensional profiles of temperature and pressure vs. altitude, which are critical

  14. GAMBARAN RADIOLOGIS PADA OCCULT PNEUMOTHORAKS

    OpenAIRE

    Putu Aditha Satya Putra; Nyoman Srie Laksminingsih

    2013-01-01

    Pneumothorax is a recognized cause of death in chest wall trauma. Radiological examination is the key factor to establish the existence of a pneumothorax. Occult pneumothorax is pneumothorax that undiagnosed clinically and with thoracic x-ray, but it can be tolerated while other more urgent trauma. Occult pneumothorax can be detected by CT (Computed tomography). Occult pneumothorax may progress to tension pneumothorax in certain circumstances. Missing in diagnosed pneumothorax will cause deat...

  15. Beamsteerable GNSS Radio Occultation ASIC

    Data.gov (United States)

    National Aeronautics and Space Administration — We will develop an integrated RF ASIC to enable high quality radio occultation (RO) weather observations using the Global Navigations System Satellite (GNSS)...

  16. The stellar occultation by the dwarf planet Haumea

    Science.gov (United States)

    Santos-Sanz, Pablo; Ortiz, Jose Luis; Sicardy, Bruno; Rossi, Gustavo; Berard, Diane; Morales, Nicolas; Duffard, Rene; Braga-Ribas, Felipe; Hopp, Ulrich; Ries, Christoph; Nascimbeni, Valerio; Marzari, Francesco; Granata, Valentina; Pál, András; Kiss, Csaba; Pribulla, Theodor; Milan Komzík, Richard; Hornoch, Kamil; Pravec, Petr; Bacci, Paolo; Maestripieri, Martina; Nerli, Luca; Mazzei, Leonardo; Bachini, Mauro; Martinelli, Fabio; Succi, Giacomo; Ciabattari, Fabrizio; Mikuz, Herman; Carbognani, Albino; Gaehrken, Bernd; Mottola, Stefano; Hellmich, Stephan; Rommel, Flavia; Fernández-Valenzuela, Estela; Campo Bagatin, Adriano; Haumea occultation international Collaboration: https://cloud.iaa.csic.es/public.php?service=files&t=d9276f8ab1a316cef13bee28bef75add

    2017-10-01

    The dwarf planet Haumea is a very peculiar Trans-Neptunian Object (TNO) with unique and exotic characteristics. It is currently classified as one of the five dwarf planets of the solar system, and it is the only one for which size, shape, albedo, density and other basic properties were not accurately known. To solve that we predicted an occultation of the star GaiaDR1 1233009038221203584 by Haumea and organized observations within the expected shadow path. Medium/large telescopes were needed to record the occultation with enough signal to noise ratio because the occulted star is of similar brightness as Haumea (R~17.7 mag). We will report results derived from this successful stellar occultation by Haumea on 2017 January 21st. The occultation was positive from 12 telescopes at 10 observing stations in Europe: the Asiago Observatory 1.8m telescope (Italy), the Mount Agliale Observatory 0.5m telescope (Italy), the Lajatico Astronomical Centre 0.5m telescope (Italy), the S.Marcello Pistoiese Observatory 0.6m telescope (Italy), the Crni Vrh Observatory 0.6m telescope (Slovenia), the Ondrejov Observatory 0.65m telescope (Czech Republic), the Bavarian Public Observatory 0.81m telescope (Germany), the Konkoly Observatory 1m and 0.6m telescopes (Hungary), the Skalnate Pleso Observatory 1.3m telescope (Slovakia), and the Wendelstein Observatory 2m and 0.4m telescopes (Germany). This is the occultation by a TNO with the largest number of chords ever recorded.Part of this work has received funding from the European Union’s Horizon 2020 Research and Innovation Programme under Grant Agreement No. 687378.

  17. Predictions of stellar occultations by TNOs/Centaurs using Gaia

    Science.gov (United States)

    Desmars, Josselin; Camargo, Julio; Berard, Diane; Sicardy, Bruno; Leiva, Rodrigo; Vieira-Martins, Roberto; Braga-Ribas, Felipe; Assafin, Marcelo; Rossi, Gustavo; Chariklo occultations Team, Rio Group, Lucky Star Occultation Team, Granada Occultation Team

    2017-10-01

    Stellar occultations are the unique technique from the ground to access physical parameters of the distant solar system objects, such as the measure of the size and the shape at kilometric level, the detection of tenuous atmospheres (few nanobars), and the investigation of close vicinity (satellites, rings, jets).Predictions of stellar occultations require accurate positions of the star and the object.The Gaia DR1 catalog now allows to get stellar position to the milliarcsecond (mas) level. The main uncertainty in the prediction remains in the position of the object (tens to hundreds of mas).Now, we take advantage of the NIMA method for the orbit determination that uses the most recent observations reduced by the Gaia DR1 catalog and the astrometric positions derived from previous positive occultations.Up to now, we have detected nearly 50 positive occultations for about 20 objects that provide astrometric positions of the object at the time of the occultation. The uncertainty of these positions only depends on the uncertainty on the position of the occulted stars, which is a few mas with the Gaia DR1 catalog. The main limitation is now on the proper motion of the star which is only given for bright stars in the Tycho-Gaia Astrometric Solution. This limitation will be solved with the publicationof the Gaia DR2 expected on April 2018 giving proper motions and parallaxes for the Gaia stars. Until this date, we use hybrid stellar catalogs (UCAC5, HSOY) that provide proper motions derived from Gaia DR1 and another stellar catalog.Recently, the Gaia team presented a release of three preliminary Gaia DR2 stellar positions involved in the occultations by Chariklo (22 June and 23 July 2017) and by Triton (5 October 2017).Taking the case of Chariklo as an illustration, we will present a comparison between the proper motions of DR2 and the other catalogs and we will show how the Gaia DR2 will lead to a mas level precision in the orbit and in the prediction of stellar

  18. Occult Phenomena in Sherlock Holmes the Movie

    OpenAIRE

    NAMAZCARRA, CHRIESHER

    2014-01-01

    Keywords: Occult phenomena, Sherlock Holmes, movie. Lately, it is not difficult for people to find occult practices. There are many television programs and movie which air mystical programme aggressively to raise the rating and attract the viewers. A movie that raise occultism theme is Sherlock Holmes, the Movie. This movie tells about the struggle of detective Sherlock Holmes to fight the black magic power of Lord Blackwood.To carry out the study, the theories of Occultism such as the secrec...

  19. Progress on the occulter experiment at Princeton

    Science.gov (United States)

    Cady, Eric; Balasubramanian, Kunjithapatham; Carr, Michael; Dickie, Matthew; Echternach, Pierre; Groff, Tyler; Kasdin, Jeremy; Laftchiev, Christian; McElwain, Michael; Sirbu, Dan; Vanderbei, Robert; White, Victor

    2009-08-01

    An occulter is used in conjunction with a separate telescope to suppress the light of a distant star. To demonstrate the performance of this system, we are building an occulter experiment in the laboratory at Princeton. This experiment will use an etched silicon mask as the occulter, with some modifications to try to improve the performance. The occulter is illuminated by a diverging laser beam to reduce the aberrations from the optics before the occulter. We present the progress of this experiment and expectations for future work.

  20. Radioimmune localization of occult carcinoma

    International Nuclear Information System (INIS)

    Duda, R.B.; Zimmer, A.M.; Rosen, S.T.; Gilyon, K.A.; Webber, D.; Spies, S.; Spies, W.; Merchant, B.

    1990-01-01

    Patients with a rising serum carcinoembryonic antigen level and no clinical or roentgenographic evidence of recurrent or metastatic cancer present a treatment dilemma. Eleven such patients, 10 with a previously treated colorectal carcinoma and 1 with a previously treated breast carcinoma, received an injection of the anticarcinoembryonic antigen monoclonal antibody ZCE-025 labeled with the radioisotope indium 111. Nuclear scintigraphy was performed on days 3 and 5 through 7 to detect potential sites of tumor recurrence. The monoclonal antibody scan accurately predicted the presence or absence of occult malignancy in 7 (64%) patients. Second-look laparotomy confirmed the monoclonal antibody scan results in the patients with colorectal cancer, and magnetic resonance imaging confirmed metastatic breast cancer. This study demonstrates that In-ZCE-025 can localize occult carcinoma and may assist the surgeon in facilitating the operative exploration. In-ZCE-025 assisted in the initiation of adjuvant therapy for the patient with breast cancer

  1. Adaptive regularization

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Rasmussen, Carl Edward; Svarer, C.

    1994-01-01

    Regularization, e.g., in the form of weight decay, is important for training and optimization of neural network architectures. In this work the authors provide a tool based on asymptotic sampling theory, for iterative estimation of weight decay parameters. The basic idea is to do a gradient desce...

  2. OCCULT POWER AND AFRICA'S SOCIO-ECONOMIC PROBLEMS ...

    African Journals Online (AJOL)

    Dr Ike

    people believe in the existence of occult powers and this belief affects their ... make use of occult powers to solve their problems. For example, ... existence and influence of paranormal and occult powers, argues that ..... and friends.

  3. Error analysis for mesospheric temperature profiling by absorptive occultation sensors

    Directory of Open Access Journals (Sweden)

    M. J. Rieder

    Full Text Available An error analysis for mesospheric profiles retrieved from absorptive occultation data has been performed, starting with realistic error assumptions as would apply to intensity data collected by available high-precision UV photodiode sensors. Propagation of statistical errors was investigated through the complete retrieval chain from measured intensity profiles to atmospheric density, pressure, and temperature profiles. We assumed unbiased errors as the occultation method is essentially self-calibrating and straight-line propagation of occulted signals as we focus on heights of 50–100 km, where refractive bending of the sensed radiation is negligible. Throughout the analysis the errors were characterized at each retrieval step by their mean profile, their covariance matrix and their probability density function (pdf. This furnishes, compared to a variance-only estimation, a much improved insight into the error propagation mechanism. We applied the procedure to a baseline analysis of the performance of a recently proposed solar UV occultation sensor (SMAS – Sun Monitor and Atmospheric Sounder and provide, using a reasonable exponential atmospheric model as background, results on error standard deviations and error correlation functions of density, pressure, and temperature profiles. Two different sensor photodiode assumptions are discussed, respectively, diamond diodes (DD with 0.03% and silicon diodes (SD with 0.1% (unattenuated intensity measurement noise at 10 Hz sampling rate. A factor-of-2 margin was applied to these noise values in order to roughly account for unmodeled cross section uncertainties. Within the entire height domain (50–100 km we find temperature to be retrieved to better than 0.3 K (DD / 1 K (SD accuracy, respectively, at 2 km height resolution. The results indicate that absorptive occultations acquired by a SMAS-type sensor could provide mesospheric profiles of fundamental variables such as temperature with

  4. Error analysis for mesospheric temperature profiling by absorptive occultation sensors

    Directory of Open Access Journals (Sweden)

    M. J. Rieder

    2001-01-01

    Full Text Available An error analysis for mesospheric profiles retrieved from absorptive occultation data has been performed, starting with realistic error assumptions as would apply to intensity data collected by available high-precision UV photodiode sensors. Propagation of statistical errors was investigated through the complete retrieval chain from measured intensity profiles to atmospheric density, pressure, and temperature profiles. We assumed unbiased errors as the occultation method is essentially self-calibrating and straight-line propagation of occulted signals as we focus on heights of 50–100 km, where refractive bending of the sensed radiation is negligible. Throughout the analysis the errors were characterized at each retrieval step by their mean profile, their covariance matrix and their probability density function (pdf. This furnishes, compared to a variance-only estimation, a much improved insight into the error propagation mechanism. We applied the procedure to a baseline analysis of the performance of a recently proposed solar UV occultation sensor (SMAS – Sun Monitor and Atmospheric Sounder and provide, using a reasonable exponential atmospheric model as background, results on error standard deviations and error correlation functions of density, pressure, and temperature profiles. Two different sensor photodiode assumptions are discussed, respectively, diamond diodes (DD with 0.03% and silicon diodes (SD with 0.1% (unattenuated intensity measurement noise at 10 Hz sampling rate. A factor-of-2 margin was applied to these noise values in order to roughly account for unmodeled cross section uncertainties. Within the entire height domain (50–100 km we find temperature to be retrieved to better than 0.3 K (DD / 1 K (SD accuracy, respectively, at 2 km height resolution. The results indicate that absorptive occultations acquired by a SMAS-type sensor could provide mesospheric profiles of fundamental variables such as temperature with

  5. Celestial shadows eclipses, transits, and occultations

    CERN Document Server

    Westfall, John

    2015-01-01

    Much of what is known about the universe comes from the study of celestial shadows—eclipses, transits, and occultations.  The most dramatic are total eclipses of the Sun, which constitute one of the most dramatic and awe-inspiring events of nature.  Though once a source of consternation or dread, solar eclipses now lead thousands of amateur astronomers and eclipse-chasers to travel to remote points on the globe to savor their beauty and the adrenaline-rush of experiencing totality, and were long the only source of information about the hauntingly beautiful chromosphere and corona of the Sun.   Long before Columbus, the curved shadow of the Earth on the Moon during a lunar eclipse revealed that we inhabit a round world. The rare and wonderful transits of Venus, which occur as it passes between the Earth and the Sun, inspired eighteenth century expeditions to measure the distance from the Earth to the Sun, while the recent transits of 2004 and 2012 were the most widely observed ever--and still produced re...

  6. First Ionospheric Results From the MAVEN Radio Occultation Science Experiment (ROSE)

    Science.gov (United States)

    Withers, Paul; Felici, M.; Mendillo, M.; Moore, L.; Narvaez, C.; Vogt, M. F.; Jakosky, B. M.

    2018-05-01

    Radio occultation observations of the ionosphere of Mars can span the full vertical extent of the ionosphere, in contrast to in situ measurements that rarely sample the main region of the ionosphere. However, most existing radio occultation electron density profiles from Mars were acquired without clear context for the solar forcing or magnetospheric conditions, which presents challenges for the interpretation of these profiles. Here we present 48 ionospheric electron density profiles acquired by the Mars Atmosphere and Volatile EvolutioN mission (MAVEN) Radio Occultation Science Experiment (ROSE) from 5 July 2016 to 27 June 2017 at solar zenith angles of 54° to 101°. Latitude coverage is excellent, and comprehensive context for the interpretation of these profiles is provided by other MAVEN instruments. The profiles show a 9-km increase in ionospheric peak altitude in January 2017 that is associated with a lower atmospheric dust storm, variations in electron densities in the M1 layer that cannot be explained by variations in the solar soft X-ray flux, and topside electron densities that are larger in strongly magnetized regions than in weakly magnetized regions. MAVEN Radio Occultation Science Experiment electron density profiles are publicly available on the NASA Planetary Data System.

  7. Sociology of religion and the occult revival

    Directory of Open Access Journals (Sweden)

    Lennart Ejerfeldt

    1975-01-01

    Full Text Available The "new" that makes the cults of the occult revival to "new religions" of the Western world, is their recently increased social significance. Historically most of modern occultism is anything but new. From the research and theorizing about the occult revival we have picked up some main themes. The first is the social diffusion of the new occultism. In this field, we find some studies of superstition, especially astrology. These illuminate the differences in social connotation between the consumers of superstition and the followers of institutional religion. Secondly the study of the occult revival has made valuable contributions to the conceptualizing of "cult" and the cultic phenomenon. Thirdly, we will look upon the connection between the occult revival and the counter-culture. The problem of the rise of cults as a symptom of socio-cultural change will be briefly discussed with reference to Bell's thesis of "the disjuntion of culture and social structure". Lastly, we proffer some reflections on the occult revival and the new spiritual trends in the churches, which so sharply contrast with the theology and churchmanship of the sixties.

  8. Effect of January 15, 2010 annular solar eclipse on meteorological parameters over Goa, India

    Digital Repository Service at National Institute of Oceanography (India)

    Muraleedharan, P.M.; Nisha, P.G.; Mohankumar, K.

    of the Sun. As a result an occultation of the solar disc takes place regularly every 223 lunar revolutions when the Moon is interposed between the Earth and the Sun. This process leads to sudden cut off of radiation for few minutes that can cause... disturbance on the thermal balance of the atmosphere. Radiative changes during a partial eclipse was measured by Abbot (1958) and found that the fractional decrease in net radiation was much greater than the fractional obscuration of the Sun’s disc...

  9. Reflective Occultation Mask for Evaluation of Occulter Designs for Planet Finding

    Science.gov (United States)

    Hagopian, John; Lyon, Richard; Shiri, Shahram; Roman, Patrick

    2011-01-01

    Advanced formation flying occulter designs utilize a large occulter mask flying in formation with an imaging telescope to block and null starlight to allow imaging of faint planets in exosolar systems. A paper describes the utilization of subscale reflective occultation masks to evaluate formation flying occulter designs. The use of a reflective mask allows mounting of the occulter by conventional means and simplifies the test configuration. The innovation alters the test set-up to allow mounting of the mask using standard techniques to eliminate the problems associated with a standard configuration. The modified configuration uses a reflective set-up whereby the star simulator reflects off of a reflective occulting mask and into an evaluation telescope. Since the mask is sized to capture all rays required for the imaging test, it can be mounted directly to a supporting fixture without interfering with the beam. Functionally, the reflective occultation mask reflects light from the star simulator instead of transmitting it, with a highly absorptive carbon nanotube layer simulating the occulter blocking mask. A subscale telescope images the star source and companion dim source that represents a planet. The primary advantage of this is that the occulter can be mounted conventionally instead of using diffractive wires or magnetic levitation.

  10. McDonald's and the Occult.

    Science.gov (United States)

    Singer, Barry

    1979-01-01

    Discusses "occult" and "paranormal" literature which is often mistaken for nonfiction. Suggests that most publishers are unwilling to publish scientific perspectives on the paranormal because such writings would be unmarketable. Journal availability: see SO 507 190. (KC)

  11. UNFOLDED REGULAR AND SEMI-REGULAR POLYHEDRA

    Directory of Open Access Journals (Sweden)

    IONIŢĂ Elena

    2015-06-01

    Full Text Available This paper proposes a presentation unfolding regular and semi-regular polyhedra. Regular polyhedra are convex polyhedra whose faces are regular and equal polygons, with the same number of sides, and whose polyhedral angles are also regular and equal. Semi-regular polyhedra are convex polyhedra with regular polygon faces, several types and equal solid angles of the same type. A net of a polyhedron is a collection of edges in the plane which are the unfolded edges of the solid. Modeling and unfolding Platonic and Arhimediene polyhedra will be using 3dsMAX program. This paper is intended as an example of descriptive geometry applications.

  12. The ionosphere of Europa from Galileo radio occultations

    Science.gov (United States)

    Kliore, A. J.; Hinson, D. P.; Flasar, F. M.; Nagy, A. F.; Cravens, T. E.

    1997-01-01

    The Galileo spacecraft performed six radio occultation observations of Jupiter's Galilean satellite Europa during its tour of the jovian system. In five of the six instances, these occultations revealed the presence of a tenuous ionosphere on Europa, with an average maximum electron density of nearly 10(4) per cubic centimeter near the surface and a plasma scale height of about 240 +/- 40 kilometers from the surface to 300 kilometers and of 440 +/- 60 kilometers above 300 kilometers. Such an ionosphere could be produced by solar photoionization and jovian magnetospheric particle impact in an atmosphere having a surface density of about 10(8) electrons per cubic centimeter. If this atmosphere is composed primarily of O2, then the principal ion is O2+ and the neutral atmosphere temperature implied by the 240-kilometer scale height is about 600 kelvin. If it is composed of H2O, the principal ion is H3O+ and the neutral temperature is about 340 kelvin. In either case, these temperatures are much higher than those observed on Europa's surface, and an external heating source from the jovian magnetosphere is required.

  13. Oligometastasis as a predictor for occult disease.

    Science.gov (United States)

    Kendal, Wayne S

    2014-05-01

    Oligometastasis can be defined as a state of limited metastases that is potentially amenable to ablative local therapy; the success of such therapy depends on whether or not additional occult metastases exist. A model is presented here to predict occult metastases given detectable oligometastases. Predictions were based on Bayes' theorem, in conjunction with descriptions of the statistical distributions for the sizes and numbers of hematogenous metastases. The background probability for occult metastases in individuals with oligometastases increased markedly with relatively minor increases in metastatic potential. With each additional metastasis detected the chance of further occult metastases increased. These latter increases were incremental and proportionately smaller with the more metastatic tumors. Long disease free intervals had a major effect to decrease in the probability of further occult disease. Demonstration of oligometastases depends heavily upon the sensitivity of radiological imaging techniques, where the proportion of detectable metastases relates to the position of the distribution of metastasis growth times with respect to the detection threshold. Given the limitations of radiological methods, and the possibility that the oligometastases detected may be the only disease, an aggressive approach appears indicated. Copyright © 2014 Elsevier Inc. All rights reserved.

  14. Unraveling current hysteresis effects in regular-type C60-CH3NH3PbI3 heterojunction solar cells.

    Science.gov (United States)

    Chen, Lung-Chien; Lin, Yu-Shiang; Tang, Po-Wen; Tai, Chao-Yi; Tseng, Zong-Liang; Lin, Ja-Hon; Chen, Sheng-Hui; Kuo, Hao-Chung

    2017-11-23

    Comprehensive studies were carried out to understand the origin of the current hysteresis effects in highly efficient C 60 -CH 3 NH 3 PbI 3 (MAPbI 3 ) heterojunction solar cells, using atomic-force microscopy, transmittance spectra, photoluminescence spectra, X-ray diffraction patterns and a femtosecond time-resolved pump-probe technique. The power conversion efficiency (PCE) of C 60 -MAPbI 3 solar cells can be increased to 18.23% by eliminating the point (lattice) defects in the MAPbI 3 thin film which is fabricated by using the one-step spin-coating method with toluene washing treatment. The experimental results show that the point defects and surface defects of the MAPbI 3 thin films can be minimized by varying the dropping time of the washing solvent. The point defects (surface defects) can be reduced with an (a) increase (decrease) in the dropping time, resulting in an optimized dropping time for obtaining the defect-minimized MAPbI 3 thin film deposited on top of the C 60 thin film. Consequently, the formation of the defect-minimized MAPbI 3 thin film allows for high-efficiency MAPbI 3 solar cells.

  15. Boundary diffraction wave integrals for diffraction modeling of external occulters

    OpenAIRE

    Cady, E.

    2012-01-01

    An occulter is a large diffracting screen which may be flown in conjunction with a telescope to image extrasolar planets. The edge is shaped to minimize the diffracted light in a region beyond the occulter, and a telescope may be placed in this dark shadow to view an extrasolar system with the starlight removed. Errors in position, orientation, and shape of the occulter will diffract additional light into this region, and a challenge of modeling an occulter system is to accurately and quickly...

  16. Coordinate-invariant regularization

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1987-01-01

    A general phase-space framework for coordinate-invariant regularization is given. The development is geometric, with all regularization contained in regularized DeWitt Superstructures on field deformations. Parallel development of invariant coordinate-space regularization is obtained by regularized functional integration of the momenta. As representative examples of the general formulation, the regularized general non-linear sigma model and regularized quantum gravity are discussed. copyright 1987 Academic Press, Inc

  17. Strong scintillations during atmospheric occultations Theoretical intensity spectra. [radio scattering during spacecraft occultations by planetary atmospheres

    Science.gov (United States)

    Hinson, D. P.

    1986-01-01

    Each of the two Voyager spacecraft launched in 1977 has completed a reconnaissance of the Jovian and Saturnian systems. In connection with occultation experiments, strong scintillations were observed. Further theoretical work is required before these scintillations can be interpreted. The present study is, therefore, concerned with the derivation of a theory for strong scattering during atmospheric occultation experiments, taking into account as fundamental quantity of interest the spatial spectrum (or spectral density) of intensity fluctuations. Attention is given to a theory for intensity spectra, and numerical calculations. The new formula derived for Phi-i accounts for strong scattering of electromagnetic waves during atmospheric occultations.

  18. Occult spondyloarthritis in inflammatory bowel disease.

    Science.gov (United States)

    Bandinelli, Francesca; Manetti, Mirko; Ibba-Manneschi, Lidia

    2016-02-01

    Spondyloarthritis (SpA) is a frequent extra-intestinal manifestation in patients with inflammatory bowel disease (IBD), although its real diffusion is commonly considered underestimated. Abnormalities in the microbioma and genetic predisposition have been implicated in the link between bowel and joint inflammation. Otherwise, up to date, pathogenetic mechanisms are still largely unknown and the exact influence of the bowel activity on rheumatic manifestations is not clearly explained. Due to evidence-based results of clinical studies, the interest on clinically asymptomatic SpA in IBD patients increased in the last few years. Actually, occult enthesitis and sacroiliitis are discovered in high percentages of IBD patients by different imaging techniques, mainly enthesis ultrasound (US) and sacroiliac joint X-ray examinations. Several diagnostic approaches and biomarkers have been proposed in an attempt to correctly classify and diagnose clinically occult joint manifestations and to define clusters of risk for patient screening, although definitive results are still lacking. The correct recognition of occult SpA in IBD requires an integrated multidisciplinary approach in order to identify common diagnostic and therapeutic strategies. The use of inexpensive and rapid imaging techniques, such as US and X-ray, should be routinely included in daily clinical practice and trials to correctly evaluate occult SpA, thus preventing future disability and worsening of quality of life in IBD patients.

  19. The Taiwanese-American occultation survey project stellar variability. III. Detection of 58 new variable stars

    Energy Technology Data Exchange (ETDEWEB)

    Ishioka, R.; Wang, S.-Y.; Zhang, Z.-W.; Lehner, M. J.; Cook, K. H.; King, S.-K.; Lee, T.; Marshall, S. L.; Schwamb, M. E.; Wang, J.-H.; Wen, C.-Y. [Institute of Astronomy and Astrophysics, Academia Sinica, 11F of Astronomy-Mathematics Building, National Taiwan University, No. 1, Sec. 4, Roosevelt Road, Taipei 10617, Taiwan (China); Alcock, C.; Protopapas, P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Axelrod, T. [Steward Observatory, 933 North Cherry Avenue, Room N204, Tucson, AZ 85721 (United States); Bianco, F. B. [Center for Cosmology and Particle Physics, New York University, 4 Washington Place, New York, NY 10003 (United States); Byun, Y.-I. [Department of Astronomy and University Observatory, Yonsei University, 134 Shinchon, Seoul 120-749 (Korea, Republic of); Chen, W. P.; Ngeow, C.-C. [Institute of Astronomy, National Central University, No. 300, Jhongda Road, Jhongli City, Taoyuan County 320, Taiwan (China); Kim, D.-W. [Max Planck Institute for Astronomy, Königstuhl 17, D-69117 Heidelberg (Germany); Rice, J. A., E-mail: ishioka@asiaa.sinica.edu.tw [Department of Statistics, University of California Berkeley, 367 Evans Hall, Berkeley, CA 94720 (United States)

    2014-04-01

    The Taiwanese-American Occultation Survey project is designed for the detection of stellar occultations by small-size Kuiper Belt Objects, and it has monitored selected fields along the ecliptic plane by using four telescopes with a 3 deg{sup 2} field of view on the sky since 2005. We have analyzed data accumulated during 2005-2012 to detect variable stars. Sixteen fields with observations of more than 100 epochs were examined. We recovered 85 variables among a total of 158 known variable stars in these 16 fields. Most of the unrecovered variables are located in the fields observed less frequently. We also detected 58 variable stars which are not listed in the International Variable Star Index of the American Association of Variable Star Observers. These variable stars are classified as 3 RR Lyrae, 4 Cepheid, 1 δ Scuti, 5 Mira, 15 semi-regular, and 27 eclipsing binaries based on the periodicity and the profile of the light curves.

  20. Occult hepatitis B infection: an evolutionary scenario

    Directory of Open Access Journals (Sweden)

    Lukashov Vladimir V

    2008-12-01

    Full Text Available Abstract Background Occult or latent hepatitis B virus (HBV infection is defined as infection with detectable HBV DNA and undetectable surface antigen (HBsAg in patients' blood. The cause of an overt HBV infection becoming an occult one is unknown. To gain insight into the mechanism of the development of occult infection, we compared the full-length HBV genome from a blood donor carrying an occult infection (d4 with global genotype D genomes. Results The phylogenetic analysis of polymerase, core and X protein sequences did not distinguish d4 from other genotype D strains. Yet, d4 surface protein formed the evolutionary outgroup relative to all other genotype D strains. Its evolutionary branch was the only one where accumulation of substitutions suggests positive selection (dN/dS = 1.3787. Many of these substitutiions accumulated specifically in regions encoding the core/surface protein interface, as revealed in a 3D-modeled protein complex. We identified a novel RNA splicing event (deleting nucleotides 2986-202 that abolishes surface protein gene expression without affecting polymerase, core and X-protein related functions. Genotype D strains differ in their ability to perform this 2986-202 splicing. Strains prone to 2986-202 splicing constitute a separate clade in a phylogenetic tree of genotype D HBVs. A single substitution (G173T that is associated with clade membership alters the local RNA secondary structure and is proposed to affect splicing efficiency at the 202 acceptor site. Conclusion We propose an evolutionary scenario for occult HBV infection, in which 2986-202 splicing generates intracellular virus particles devoid of surface protein, which subsequently accumulates mutations due to relaxation of coding constraints. Such viruses are deficient of autonomous propagation and cannot leave the host cell until it is lysed.

  1. Occult diaphragmatic injuries caused by stab wounds.

    Science.gov (United States)

    Leppäniemi, Ari; Haapiainen, Reijo

    2003-10-01

    Missed diaphragmatic perforation caused by penetrating trauma can lead to subsequent strangulation of a hollow viscus, which has prompted the use of invasive diagnostic procedures to exclude occult diaphragmatic injuries in asymptomatic, high-risk patients. The objective of this study was to determine the incidence of occult diaphragmatic injuries caused by stab wounds of the lower chest and upper abdomen, and to examine the natural history and consequences of missed diaphragmatic injuries. On the basis of patient data from two previous randomized studies from our institution, a retrospective analysis was performed on 97 patients treated for anterior stab wounds located between the nipple line, the umbilical level, and the posterior axillary lines not having indications for immediate surgical exploration. The patients were divided into two groups on the basis of their initial randomized management (open or laparoscopic exploration vs. expectant observation). In the exploration group (n = 47), four diaphragmatic injuries (9%) were detected (three left-sided and one right-sided). Excluding patients with associated injuries requiring surgical repair, the incidence of occult diaphragmatic injuries was 3 of 43 (7%). In the observation group (n = 50), there were two patients (4%) with delayed presentation of missed left-sided diaphragmatic injury 2 and 23 months later, respectively. Both injuries resulted from stab wounds of the left flank and presented with herniation of the stomach or small bowel and colon. The overall incidence of occult diaphragmatic injuries in left-sided thoracoabdominal stab wounds was 4 of 24 (17%), and was much lower after stab wounds of left epigastrium (0%), right lower chest (0%), and right epigastrium (4%). In asymptomatic patients with anterior or flank stab wounds of the lower chest or upper abdominal area, the risk of an occult diaphragmatic injury is approximately 7% which, if undetected, is associated with a high risk of subsequent

  2. Atmospheric diurnal variations observed with GPS radio occultation soundings

    Directory of Open Access Journals (Sweden)

    F. Xie

    2010-07-01

    Full Text Available The diurnal variation, driven by solar forcing, is a fundamental mode in the Earth's weather and climate system. Radio occultation (RO measurements from the six COSMIC satellites (Constellation Observing System for Meteorology, Ionosphere and Climate provide nearly uniform global coverage with high vertical resolution, all-weather and diurnal sampling capability. This paper analyzes the diurnal variations of temperature and refractivity from three-year (2007–2009 COSMIC RO measurements in the troposphere and stratosphere between 30° S and 30° N. The RO observations reveal both propagating and trapped vertical structures of diurnal variations, including transition regions near the tropopause where data with high vertical resolution are critical. In the tropics the diurnal amplitude in refractivity shows the minimum around 14 km and increases to a local maximum around 32 km in the stratosphere. The upward propagating component of the migrating diurnal tides in the tropics is clearly captured by the GPS RO measurements, which show a downward progression in phase from stratopause to the upper troposphere with a vertical wavelength of about 25 km. At ~32 km the seasonal variation of the tidal amplitude maximizes at the opposite side of the equator relative to the solar forcing. The vertical structure of tidal amplitude shows strong seasonal variations and becomes asymmetric along the equator and tilted toward the summer hemisphere in the solstice months. Such asymmetry becomes less prominent in equinox months.

  3. Occult fractures of the knee: tomographic evaluation

    International Nuclear Information System (INIS)

    Apple, J.S.; Martinez, S.; Allen, N.B.; Caldwell, D.S.; Rice, J.R.

    1983-01-01

    Seven adults with painful effusions of the knee were examined for occult fractures using pluridirectional tomograph in the coronal and lateral planes. Six patients (ages 50 to 82 years) were osteopenic and gave histories ranging from none to mild trauma; one 26-year-old man was not osteopenic and had severe trauma. In all cases, routine radiographs were interpreted as negative, but tomography demonstrated a fracture. Five fractures were subchondral. Bone scans in 2 patients were positive. The authors conclude that osteopenic patients with a painful effusion of the knee should be considered to have an occult fracture. While bone scans may be helpful, tomography is recommended as the procedure of choice to define the location and extent of the fracture

  4. Paraneoplastic retinopathy associated with occult bladder cancer

    DEFF Research Database (Denmark)

    Nivean, M; Muttuvelu, Danson V; Afzelius, Pia Maria Tullia

    2016-01-01

    (ERG), serology including serum antibodies for CAR, and positron emission tomography-computed tomography (PET-CT) scan. The patient was diagnosed with bladder carcinoma revealed by PET-CT. Timely recognition of this entity may be crucial for an increased patient survival thus adult onset progressive...... photoreceptor dysfunction, confirmed by ERG, should alert to a possible remote effect of known or occult malignancy. In the latter, PET-CT may be exploited as a powerful diagnostic tool....

  5. ASTEROID SIZING BY RADIOGALAXY OCCULTATION AT 5 GHZ

    Energy Technology Data Exchange (ETDEWEB)

    Lehtinen, K.; Muinonen, K.; Poutanen, M. [Finnish Geospatial Research Institute FGI, Geodeetinrinne 2, FI-02430 Masala (Finland); Bach, U. [Max-Planck-Institut für Radioastronomie, Radioobservatorium Effelsberg, Max-Planck-Str. 28, D-53902 Bad Münstereifel-Effelsberg (Germany); Petrov, L., E-mail: kimmo.lehtinen@nls.fi [Astrogeo Center, Falls Church, VA 22043 (United States)

    2016-05-10

    Stellar occultations by asteroids observed at visual wavelengths have been an important tool for studying the size and shape of asteroids and for revising the orbital parameters of asteroids. At radio frequencies, a shadow of an asteroid on the Earth is dominated by diffraction effects. Here, we show, for the first time, that a single observation of an occultation of a compact radio source at a frequency of 5 GHz can be used to derive the effective size of the occulting object and to derive the distance between the observer and the center of the occultation path on the Earth. The derived diameter of the occulting object, asteroid (115) Thyra, is 75 ± 6 km. The observed occultation profile shows features that cannot be explained by diffraction of a single asteroid.

  6. OCCULTISM AND MEDIUMSHIP IN FERNANDO PESSOA

    Directory of Open Access Journals (Sweden)

    Alisson Diêgo Dias de Medeiros

    2016-03-01

    Full Text Available This work is the result of a research on the influence that the occultism had on the work of the Portuguese poet Fernando Pessoa. To delimitate the study, we selected papers of Fernando Pessoa, which  suggested that the poet considered himself medium, and hence influenced his work, building his depersonalization. This work presents, thus, as main objectiveto analyze personal papers of Fernando Pessoa, whose outstanding characteristic is the presence of occultism and the supposed mediumship defended by him in response to non-literary and heteronymic manifestations. To this end, I focused on specific objectives, which are: a to study the speech of Fernando Pessoa on his supposed mediumship / occultism b to analyze specific texts that are, for the poet, mediumistic manifestations c to study excerpts from a set of personal letters in which Fernando Pessoa suggested being a medium. It is true that this dissertation will address many discussions already made by scholars and specialists in Fernando Pessoa, but we consider the possibility to deepen issues and contribute to the critical fortune of the poet.

  7. Ultrasound detection of nonpalpable mammographically occult malignancy

    International Nuclear Information System (INIS)

    Simpson, W.L.; Hermann, G.; Rausch, D.R.; Sherman, J.; Feig, S.A.; Bleiweiss, I.J.; Jaffer, S.

    2008-01-01

    To evaluate the prevalence of occult malignancy with screening breast ultrasound. All ultrasound-guided core needle breast biopsies performed between January 1, 1999, and June 30, 2001, were retrospectively reviewed. Lesions were identified during screening breast ultrasound in high-risk women with no mammographic or palpable abnormality in either breast, a unilateral mammographic or palpable abnormality in the contralateral breast, or a unilateral mammographic or palpable abnormality in a different quadrant of the same breast. All ultrasound-detected lesions were histologically verified. Six hundred and fifty-two women with a mean age of 49 years underwent 698 biopsies during the study period. Three hundred and forty-nine of these lesions were detected at screening breast ultrasound. Out of 349, 11 (3.2%) had a mammographically and clinically occult malignancy. Nine cancers were found in women with no mammographic or palpable abnormality. Two cancers were found in the same breast as the mammographic or palpable abnormality. None were found in the breast contralateral to a palpable or mammographic abnormality. Screening breast ultrasound of high-risk women has a similar detection rate for occult carcinoma as screening mammography, but has a low positive predictive value in cases where biopsy is performed. (author)

  8. OCCULT-ORSER complete conversational user-language translator

    Science.gov (United States)

    Ramapriyan, H. K.; Young, K.

    1981-01-01

    Translator program (OCCULT) assists non-computer-oriented users in setting up and submitting jobs for complex ORSER system. ORSER is collection of image processing programs for analyzing remotely sensed data. OCCULT is designed for those who would like to use ORSER but cannot justify acquiring and maintaining necessary proficiency in Remote Job Entry Language, Job Control Language, and control-card formats. OCCULT is written in FORTRAN IV and OS Assembler for interactive execution.

  9. Distance-regular graphs

    NARCIS (Netherlands)

    van Dam, Edwin R.; Koolen, Jack H.; Tanaka, Hajime

    2016-01-01

    This is a survey of distance-regular graphs. We present an introduction to distance-regular graphs for the reader who is unfamiliar with the subject, and then give an overview of some developments in the area of distance-regular graphs since the monograph 'BCN'[Brouwer, A.E., Cohen, A.M., Neumaier,

  10. LL-regular grammars

    NARCIS (Netherlands)

    Nijholt, Antinus

    1980-01-01

    Culik II and Cogen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this paper we consider an analogous extension of the LL(k) grammars called the LL-regular grammars. The relation of this class of grammars to other classes of grammars will be shown. Any LL-regular

  11. Regular Expression Pocket Reference

    CERN Document Server

    Stubblebine, Tony

    2007-01-01

    This handy little book offers programmers a complete overview of the syntax and semantics of regular expressions that are at the heart of every text-processing application. Ideal as a quick reference, Regular Expression Pocket Reference covers the regular expression APIs for Perl 5.8, Ruby (including some upcoming 1.9 features), Java, PHP, .NET and C#, Python, vi, JavaScript, and the PCRE regular expression libraries. This concise and easy-to-use reference puts a very powerful tool for manipulating text and data right at your fingertips. Composed of a mixture of symbols and text, regular exp

  12. Prevalence of occult inflammatory bowel disease in ankylosing spondylitis.

    Science.gov (United States)

    Costello, P B; Alea, J A; Kennedy, A C; McCluskey, R T; Green, F A

    1980-10-01

    Fifty-five patients with ankylosing spondylitis and 16 control patients matched for sex and age were examined for evidence of occult inflammatory bowel disease. In all patients evaluation included history and physical examination, barium enema, sigmoidoscopy, and rectal biopsy. The results of this study suggest that there is no increased prevalence of occult inflammatory bowel disease in patients with ankylosing spondylitis.

  13. 21 CFR 864.6550 - Occult blood test.

    Science.gov (United States)

    2010-04-01

    ... 21 Food and Drugs 8 2010-04-01 2010-04-01 false Occult blood test. 864.6550 Section 864.6550 Food and Drugs FOOD AND DRUG ADMINISTRATION, DEPARTMENT OF HEALTH AND HUMAN SERVICES (CONTINUED) MEDICAL DEVICES HEMATOLOGY AND PATHOLOGY DEVICES Manual Hematology Devices § 864.6550 Occult blood test. (a...

  14. Molecular and serological detection of occult hepatitis B virus ...

    African Journals Online (AJOL)

    Background: Occult hepatitis B infections are becoming a major global threat, but the available data on its prevalence in various parts of the world are often divergent. Objective: This study aimed to detect occult hepatitis B virus in hepatitis B surface antigen-negative serum using anti-HBc as a marker of previous infection.

  15. Occult Hepatitis B Virus in Gezira State Sudan | Gasmelseed ...

    African Journals Online (AJOL)

    Background: Occult hepatitis B infection (OBI) is simply defined as serologically undetectable hepatitis B surface antigen (HBsAg-ve), despite the presence of circulating HBV DNA. Objective: The aim of this study was to determine the prevalence of occult HBV among Screened HBsAg subjects in Gezira State, Sudan.

  16. Radio Occultation Bending Angle Anomalies During Tropical Cyclones

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, Stig

    signature in radio occultation profiles in the tropical tropopause layer. Using tropical cyclone best track database and data from the Constellation Observing System for Meteorology, Ionosphere and Climate (COSMIC), we show that the bending angle anomaly of a GPS radio occultation signal is typically larger...

  17. Esophageal Metastasis From Occult Lung Cancer

    Directory of Open Access Journals (Sweden)

    Po-Kuei Hsu

    2010-06-01

    Full Text Available A 66-year-old man with dysphagia was found to have a poorly differentiated esophageal carcinoma by incision biopsy. Following esophagectomy, reconstruction with a gastric tube was performed. Pathological examination and immunohisto-chemistry showed infiltration of adenocarcinoma cells with positive thyroid transcription factor 1-staining in the submucosal layer, which indicated metastatic esophageal carcinoma. Although no pulmonary lesion could be visualized by imaging or bronchoscopy, pulmonary origin was highly suspected as a result of positive thyroid transcription factor 1-staining. To the best of our knowledge, this is the first reported case of metastatic esophageal carcinoma from occult lung cancer (AJCC TNM stage TX.

  18. Neurogenic bladder from occult herpes zoster.

    Science.gov (United States)

    Rothrock, J F; Walicke, P A; Swenson, M R

    1986-11-01

    Active infection with herpes zoster may cause acute urinary retention, especially when it involves sacral dermatomes. Although frank retention usually develops days to weeks after eruption of the typical rash, bladder incompetence infrequently develops first, raising concern over other, more ominous etiologies. In the case presented, rash appearance was delayed until six weeks after the initial onset of urinary retention, a much longer interval than previously reported. Occult herpes zoster infection should be considered in patients presenting with an acute neurogenic bladder of obscure cause.

  19. Regularization by External Variables

    DEFF Research Database (Denmark)

    Bossolini, Elena; Edwards, R.; Glendinning, P. A.

    2016-01-01

    Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind of regula......Regularization was a big topic at the 2016 CRM Intensive Research Program on Advances in Nonsmooth Dynamics. There are many open questions concerning well known kinds of regularization (e.g., by smoothing or hysteresis). Here, we propose a framework for an alternative and important kind...

  20. Regular expressions cookbook

    CERN Document Server

    Goyvaerts, Jan

    2009-01-01

    This cookbook provides more than 100 recipes to help you crunch data and manipulate text with regular expressions. Every programmer can find uses for regular expressions, but their power doesn't come worry-free. Even seasoned users often suffer from poor performance, false positives, false negatives, or perplexing bugs. Regular Expressions Cookbook offers step-by-step instructions for some of the most common tasks involving this tool, with recipes for C#, Java, JavaScript, Perl, PHP, Python, Ruby, and VB.NET. With this book, you will: Understand the basics of regular expressions through a

  1. Lunar occultation observations of the Crab Nebula

    International Nuclear Information System (INIS)

    Maloney, F.P.

    1977-01-01

    Three lunar of occultations of the Crab Nebula were observed, two at 114 MHz and one at 26.3 MHz, during the 1974 series of events. The higher frequency observations were deconvolved of diffraction effects to yield four strip integrated brightness profiles of the Nebula, with an effective resolution of 30 arc-seconds. These four profiles were Fourier inverted and cleaned of sidelobe structure to synthesize a two-dimensional map of the Nebula. At 114 MHz, the Nebula is composed of a broad envelope of emission which contains several smaller sources. The attenuation of the low radio frequency radiation by the thermal hydrogen in the filaments is considered as a possible mechanism to explain these new data. The 26.3 MHz observations indicate the presence of a bright, localized source containing greater than 80% of the flux of the Nebula. The position of the source is confined by the data to a narrow strip centered at the pulsar position. Both sets of data are compared with past occultation observations

  2. Air-cooling mathematical analysis as inferred from the air-temperature observation during the 1st total occultation of the Sun of the 21st century at Lusaka, Zambia

    Science.gov (United States)

    Peñaloza-Murillo, Marcos A.; Pasachoff, Jay M.

    2015-04-01

    We analyze mathematically air temperature measurements made near the ground by the Williams College expedition to observe the first total occultation of the Sun [TOS (commonly known as a total solar eclipse)] of the 21st century in Lusaka, Zambia, in the afternoon of June 21, 2001. To do so, we have revisited some earlier and contemporary methods to test their usefulness for this analysis. Two of these methods, based on a radiative scheme for solar radiation modeling and that has been originally applied to a morning occultation, have successfully been combined to obtain the delay function for an afternoon occultation, via derivation of the so-called instantaneous temperature profiles. For this purpose, we have followed the suggestion given by the third of these previously applied methods to calculate this function, although by itself it failed to do so at least for this occultation. The analysis has taken into account the limb-darkening, occultation and obscuration functions. The delay function obtained describes quite fairly the lag between the solar radiation variation and the delayed air temperature measured. Also, in this investigation, a statistical study has been carried out to get information on the convection activity produced during this event. For that purpose, the fluctuations generated by turbulence has been studied by analyzing variance and residuals. The results, indicating an irreversible steady decrease of this activity, are consistent with those published by other studies. Finally, the air temperature drop due to this event is well estimated by applying the empirical scheme given by the fourth of the previously applied methods, based on the daily temperature amplitude and the standardized middle time of the occultation. It is demonstrated then that by using a simple set of air temperature measurements obtained during solar occultations, along with some supplementary data, a simple mathematical analysis can be achieved by applying of the four

  3. Current management of occult bacteremia in infants

    Directory of Open Access Journals (Sweden)

    Eduardo Mekitarian Filho

    2015-11-01

    Full Text Available Objectives: To summarize the main clinical entities associated with fever without source (FWS in infants, as well as the clinical management of children with occult bacteremia, emphasizing laboratory tests and empirical antibiotics. Sources: A non-systematic review was conducted in the following databases – PubMed, EMBASE, and SciELO, between 2006 and 2015. Summary of the findings: The prevalence of occult bacteremia has been decreasing dramatically in the past few years, due to conjugated vaccination against Streptococcus pneumoniae and Neisseria meningitidis. Additionally, fewer requests for complete blood count and blood cultures have been made for children older than 3 months presenting with FWS. Urinary tract infection is the most prevalent bacterial infection in children with FWS. Some known algorithms, such as Boston and Rochester, can guide the initial risk stratification for occult bacteremia in febrile infants younger than 3 months. Conclusions: There is no single algorithm to estimate the risk of occult bacteremia in febrile infants, but pediatricians should strongly consider outpatient management in fully vaccinated infants older than 3 months with FWS and good general status. Updated data about the incidence of occult bacteremia in this environment after conjugated vaccination are needed. Resumo: Objetivos: Listar as principais entidades clínicas associadas a quadros de febre sem sinais localizatórios (FSSL em lactentes, bem como o manejo dos casos de bacteremia oculta com ênfase na avaliação laboratorial e na antibioticoterapia empírica. Fonte dos dados: Foi realizada revisão não sistemática da literatura nas bases de dados PubMed, EMBASE e Scielo no período de 2006 a 2015. Síntese dos dados: A ocorrência de bacteremia oculta vem diminuindo sensivelmente em lactentes com FSSL, principalmente devido à introdução da vacinação conjugada contra Streptococcus pneumoniae e Neisseria meningitidis nos últimos anos

  4. Regularities of Multifractal Measures

    Indian Academy of Sciences (India)

    First, we prove the decomposition theorem for the regularities of multifractal Hausdorff measure and packing measure in R R d . This decomposition theorem enables us to split a set into regular and irregular parts, so that we can analyze each separately, and recombine them without affecting density properties. Next, we ...

  5. Stochastic analytic regularization

    International Nuclear Information System (INIS)

    Alfaro, J.

    1984-07-01

    Stochastic regularization is reexamined, pointing out a restriction on its use due to a new type of divergence which is not present in the unregulated theory. Furthermore, we introduce a new form of stochastic regularization which permits the use of a minimal subtraction scheme to define the renormalized Green functions. (author)

  6. Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation (ADONIS mission proposal

    Directory of Open Access Journals (Sweden)

    Hettrich Sebastian

    2015-01-01

    Full Text Available The Atmospheric Drag, Occultation ‘N’ Ionospheric Scintillation mission (ADONIS studies the dynamics of the terrestrial thermosphere and ionosphere in dependency of solar events over a full solar cycle in Low Earth Orbit (LEO. The objectives are to investigate satellite drag with in-situ measurements and the ionospheric electron density profiles with radio occultation and scintillation measurements. A constellation of two satellites provides the possibility to gain near real-time data (NRT about ionospheric conditions over the Arctic region where current coverage is insufficient. The mission shall also provide global high-resolution data to improve assimilative ionospheric models. The low-cost constellation can be launched using a single Vega rocket and most of the instruments are already space-proven allowing for rapid development and good reliability. From July 16 to 25, 2013, the Alpbach Summer School 2013 was organised by the Austrian Research Promotion Agency (FFG, the European Space Agency (ESA, the International Space Science Institute (ISSI and the association of Austrian space industries Austrospace in Alpbach, Austria. During the workshop, four teams of 15 students each independently developed four different space mission proposals on the topic of “Space Weather: Science, Missions and Systems”, supported by a team of tutors. The present work is based on the mission proposal that resulted from one of these teams’ efforts.

  7. Fecal Occult Blood Test and Gastrointestinal Parasitic Infection

    Directory of Open Access Journals (Sweden)

    Majed H. Wakid

    2010-01-01

    Full Text Available Stool specimens of 1238 workers in western region of Saudi Arabia were examined for infection with intestinal parasites and for fecal occult blood (FOB to investigate the possibility that enteroparasites correlate to occult intestinal bleeding. Direct smears and formal ether techniques were used for detection of diagnostic stages of intestinal parasites. A commercially available guaiac test was used to detect fecal occult blood. 47.01% of the workers were infected with intestinal parasites including eight helminthes species and eight protozoan species. The results provided no significant evidence (P-value=0.143 that intestinal parasitic infection is in association with positive guaiac FOB test.

  8. CT detection of occult pneumothorax in head trauma

    International Nuclear Information System (INIS)

    Tocino, I.M.; Miller, M.H.; Frederick, P.R.; Bahr, A.L.; Thomas, F.

    1984-01-01

    A prospective evaluation for occult pneumothorax was performed in 25 consecutive patients with serious head trauma by combining a limited chest CT examination with the emergency head CT examination. Of 21 pneuomothoraces present in 15 patients, 11 (52%) were found only by chest CT and were not identified clinically or by supine chest radiograph. Because of pending therapeutic measures, chest tubes were placed in nine of the 11 occult pneumothoraces, regardless of the volume. Chest CT proved itself as the most sensitive method for detection of occult pneumothorax, permitting early chest tube placement to prevent transition to a tension pneumothorax during subsequent mechanical ventilation or emergency surgery under general anesthesia

  9. CT detection of occult pneumothorax in head trauma

    Energy Technology Data Exchange (ETDEWEB)

    Tocino, I.M.; Miller, M.H.; Frederick, P.R.; Bahr, A.L.; Thomas, F.

    1984-11-01

    A prospective evaluation for occult pneumothorax was performed in 25 consecutive patients with serious head trauma by combining a limited chest CT examination with the emergency head CT examination. Of 21 pneuomothoraces present in 15 patients, 11 (52%) were found only by chest CT and were not identified clinically or by supine chest radiograph. Because of pending therapeutic measures, chest tubes were placed in nine of the 11 occult pneumothoraces, regardless of the volume. Chest CT proved itself as the most sensitive method for detection of occult pneumothorax, permitting early chest tube placement to prevent transition to a tension pneumothorax during subsequent mechanical ventilation or emergency surgery under general anesthesia.

  10. Profiling Saturn's rings by radio occultation

    International Nuclear Information System (INIS)

    Marouf, E.A.; Tyler, G.L.; Rosen, P.A.

    1986-01-01

    The development of reconstruction algorithms that correct for diffraction effects in radio occultation measurements is described. The reciprocal Fresnel transform relationship between the complex amplitude of the observed coherent signal and the complex microwave transmittance of the rings is derived using the Huygens-Fresnel formulation of the diffraction problem. The effects of the finite data segment width, the uncertainties in the Fresnel scale, systematic phase errors in the kernel of the inverse transform, reference oscillator instabilities, and random noise measurements on the resolution of the reconstructed transmittance are analyzed. Examples of reconstructed opacity profiles for some regions of Saturn's rings derived by applying the reconstruction theory to Voyager 1 at Saturn data are presented. 35 references

  11. Diagnosis of occult abdominal abscesses using radioisotopes

    International Nuclear Information System (INIS)

    Koch, B.; Schroth, H.J.; Wolf, N.; Wilhelm, H.; Universitaet des Saarlandes, Homburg/Saar

    1983-01-01

    Occult intraperitoneal abscesses are difficult to localize and dispose of. Therefore, a method of examination is needed that is specific, can be used at any time, is not expensive, and yields early results within 2-3 h. This seems possible with a new method of examination. sup(99m)Tc-Sn-colloid was used to label autologous polymorphonuclear leukocytes which, when reinjected, emigrate to the site of the suspected abscess. Standard scintigraphy localizes the labeled inflammatory cells. Scans were performed in 57 surgical patients with good results. 23 (40,4%) patients had true negative results; 28 (49,1%) scans represented intraperitoneal abscesses; 5 (8,8%) scans demonstrated true positive extraperitoneal inflammations. Only 1 (1,7%) scan was false positive. (orig.) [de

  12. Sparse structure regularized ranking

    KAUST Repository

    Wang, Jim Jing-Yan; Sun, Yijun; Gao, Xin

    2014-01-01

    Learning ranking scores is critical for the multimedia database retrieval problem. In this paper, we propose a novel ranking score learning algorithm by exploring the sparse structure and using it to regularize ranking scores. To explore the sparse

  13. Regular expression containment

    DEFF Research Database (Denmark)

    Henglein, Fritz; Nielsen, Lasse

    2011-01-01

    We present a new sound and complete axiomatization of regular expression containment. It consists of the conventional axiomatiza- tion of concatenation, alternation, empty set and (the singleton set containing) the empty string as an idempotent semiring, the fixed- point rule E* = 1 + E × E......* for Kleene-star, and a general coin- duction rule as the only additional rule. Our axiomatization gives rise to a natural computational inter- pretation of regular expressions as simple types that represent parse trees, and of containment proofs as coercions. This gives the axiom- atization a Curry......-Howard-style constructive interpretation: Con- tainment proofs do not only certify a language-theoretic contain- ment, but, under our computational interpretation, constructively transform a membership proof of a string in one regular expres- sion into a membership proof of the same string in another regular expression. We...

  14. Supersymmetric dimensional regularization

    International Nuclear Information System (INIS)

    Siegel, W.; Townsend, P.K.; van Nieuwenhuizen, P.

    1980-01-01

    There is a simple modification of dimension regularization which preserves supersymmetry: dimensional reduction to real D < 4, followed by analytic continuation to complex D. In terms of component fields, this means fixing the ranges of all indices on the fields (and therefore the numbers of Fermi and Bose components). For superfields, it means continuing in the dimensionality of x-space while fixing the dimensionality of theta-space. This regularization procedure allows the simple manipulation of spinor derivatives in supergraph calculations. The resulting rules are: (1) First do all algebra exactly as in D = 4; (2) Then do the momentum integrals as in ordinary dimensional regularization. This regularization procedure needs extra rules before one can say that it is consistent. Such extra rules needed for superconformal anomalies are discussed. Problems associated with renormalizability and higher order loops are also discussed

  15. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yunji; Jing, Bing-Yi; Gao, Xin

    2015-01-01

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  16. Regularized maximum correntropy machine

    KAUST Repository

    Wang, Jim Jing-Yan

    2015-02-12

    In this paper we investigate the usage of regularized correntropy framework for learning of classifiers from noisy labels. The class label predictors learned by minimizing transitional loss functions are sensitive to the noisy and outlying labels of training samples, because the transitional loss functions are equally applied to all the samples. To solve this problem, we propose to learn the class label predictors by maximizing the correntropy between the predicted labels and the true labels of the training samples, under the regularized Maximum Correntropy Criteria (MCC) framework. Moreover, we regularize the predictor parameter to control the complexity of the predictor. The learning problem is formulated by an objective function considering the parameter regularization and MCC simultaneously. By optimizing the objective function alternately, we develop a novel predictor learning algorithm. The experiments on two challenging pattern classification tasks show that it significantly outperforms the machines with transitional loss functions.

  17. Atmospheric stability index using radio occultation refractivity profiles

    Indian Academy of Sciences (India)

    A new stability index based on atmospheric refractivity at ∼500 hPa level and surface measurements of temperature ... able at different heights rather than pressure levels. However ..... the radio occultation technique being a limb sound-.

  18. UARS Halogen Occultation Experiment (HALOE) Level 2 V001

    Data.gov (United States)

    National Aeronautics and Space Administration — The HALOE home page on the WWW is http://haloe.gats-inc.com/home/index.php The Halogen Occultation Experiment (HALOE) on NASA's Upper Atmosphere Research Satellite...

  19. Photoreceptor atrophy in acute zonal occult outer retinopathy

    DEFF Research Database (Denmark)

    Zibrandtsen, N.; Munch, I.C.; Klemp, K.

    2006-01-01

    Purpose: To assess retinal morphology in acute zonal occult outer retinopathy (AZOOR). Methods: Three patients with a normal ophthalmoscopic fundus appearance, a history of photopsia, and visual field loss compatible with AZOOR were examined using optical coherence tomography, automated perimetry...

  20. Diagnostic strategy for occult hepatitis B virus infection

    Science.gov (United States)

    Ocana, Sara; Casas, Maria Luisa; Buhigas, Ingrid; Lledo, Jose Luis

    2011-01-01

    In 2008, the European Association for the study of the liver (EASL) defined occult hepatitis B virus infection (OBI) as the “presence of hepatitis B virus (HBV) DNA in the liver (with detectable or undetectable HBV DNA in the serum) of individuals testing hepatitis B surface antigen (HBsAg) negative by currently available assays”. Several aspects of occult HBV infection are still poorly understood, including the definition itself and a standardized approach for laboratory-based detection, which is the purpose of this review. The clinical significance of OBI has not yet been established; however, in terms of public health, the clinical importance arises from the risk of HBV transmission. Consequently, it is important to detect high-risk groups for occult HBV infection to prevent transmission. The main issue is, perhaps, to identify the target population for screening OBI. Viremia is very low or undetectable in occult HBV infection, even when the most sensitive methods are used, and the detection of the viral DNA reservoir in hepatocytes would provide the best evaluation of occult HBV prevalence in a defined set of patients. However, this diagnostic approach is obviously unsuitable: blood detection of occult hepatitis B requires assays of the highest sensitivity and specificity with a lower limit of detection < 10 IU/mL for HBV DNA and < 0.1 ng/mL for HBsAg. PMID:21472120

  1. Possible occultation by Pluto from US East Coast

    Science.gov (United States)

    Waagen, Elizabeth O.

    2012-06-01

    We have been asked to help disseminate the news of a possible occultation by Pluto visible to observers on the US East coast. Although the AAVSO does not ordinarily issue announcements of upcoming occultations, in this case the object is Pluto and the NASA New Horizons mission (http://www.nasa.gov/mission_pages/newhorizons/main/index.html) will be visiting Pluto in 2015. The information below has been supplied by Dr. Leslie Young (Southwest Research Institute), who is coordinating this observing campaign on Pluto. Dr. Young is also Deputy Project Scientist for the New Horizons mission. ALERT: Possible Pluto occultation Wednesday night (2012/06/14 03:28 UT) from US East coast. CONTACT: Leslie Young (layoung@boulder.swri.edu; work: 303-546-6057; skype: drpluto). Also see our planning pages in progress at http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation. Pluto's thin, nitrogen atmosphere is in vapor-pressure equilibrium with the surface ice, and changes seasonally. We've seen it double since 1988, and now we measure its pressure once or twice a year. The technique we use is stellar occultation, when a star passes behind Pluto's atmosphere. The atmosphere defocuses the starlight. By the timing of the fading of the star, we measure the pressure and temperature in Pluto's atmosphere at ~10 km resolution. MORE INFORMATION: See http://wiki.boulder.swri.edu/mediawiki/index.php/2012-06-14_Pluto_occultation.

  2. Astr 101 Students' Attitudes Towards Essays On Transits, Eclipses And Occultations

    Science.gov (United States)

    D'Cruz, Noella L.

    2012-05-01

    Joliet Junior College, Joliet, IL offers a one semester introductory astronomy course each semester. We teach over 110 primarily non-science major students each semester. We use proven active learning strategies such lecture tutorials, think-pair-share questions and small group discussions to help these students develop and retain a good understanding of astrophysical concepts. Occasionally, we offer projects that allow students to explore course topics beyond the classroom. We hope that such projects will increase students' interest in astronomy. We also hope that these assignments will help students to improve their critical thinking and writing skills. In Spring 12, we are offering three short individual essay assignments in our face-to-face sections. The essays focus on transits, eclipses and occultations to highlight the 2012 transit of Venus. For the first essay, students will find images of transit and occultation events using the Astronomy Picture of the Day website and describe their chosen events. In addition, students will predict how variations in certain physical and orbital parameters would alter their particular events. The second essay involves transits, eclipses and occultations observed by spacecraft. Students will describe their transit event, their spacecraft's mission, orbital path, how the orbital path was achieved, etc. The third essay deals with transiting exoplanets. Students will choose at least two exoplanets from an exoplanet database, one of which has been discovered through the transit method. This essay will enable students to learn about detecting exoplanets and how they compare with our solar system. Details of the essay assignments and students' reactions to them will be presented at the meeting.

  3. Manifold Regularized Reinforcement Learning.

    Science.gov (United States)

    Li, Hongliang; Liu, Derong; Wang, Ding

    2018-04-01

    This paper introduces a novel manifold regularized reinforcement learning scheme for continuous Markov decision processes. Smooth feature representations for value function approximation can be automatically learned using the unsupervised manifold regularization method. The learned features are data-driven, and can be adapted to the geometry of the state space. Furthermore, the scheme provides a direct basis representation extension for novel samples during policy learning and control. The performance of the proposed scheme is evaluated on two benchmark control tasks, i.e., the inverted pendulum and the energy storage problem. Simulation results illustrate the concepts of the proposed scheme and show that it can obtain excellent performance.

  4. Occult pneumomediastinum in blunt chest trauma: clinical significance.

    Science.gov (United States)

    Rezende-Neto, J B; Hoffmann, J; Al Mahroos, M; Tien, H; Hsee, L C; Spencer Netto, F; Speers, V; Rizoli, S B

    2010-01-01

    Thoracic injuries are potentially responsible for 25% of all trauma deaths. Chest X-ray is commonly used to screen patients with chest injury. However, the use of computed tomography (CT) scan for primary screening is increasing, particularly for blunt trauma. CT scans are more sensitive than chest X-ray in detecting intra-thoracic abnormalities such as pneumothoraces and pneumomediastinums. Pneumomediastinum detected by chest X-ray or "overt pneumomediastinum", raises the concern of possible aerodigestive tract injuries. In contrast, there is scarce information on the clinical significance of pneumomediastinum diagnosed by CT scan only or "occult pneumomediastinum". Therefore we investigated the clinical consequences of occult pneumomediastinum in our blunt trauma population. A 2-year retrospective chart review of all blunt chest trauma patients with initial chest CT scan admitted to a level I trauma centre. Data extracted from the medical records include; demographics, occult, overt, or no pneumomediastinum, the presence of intra-thoracic aerodigestive tract injuries (trachea, bronchus, and/or esophagus), mechanism and severity of injury, endotracheal intubation, chest thoracostomy, operations and radiological reports by an attending radiologist. All patients with intra-thoracic aerodigestive tract injuries from 1994 to 2004 were also investigated. Of 897 patients who met the inclusion criteria 839 (93.5%) had no pneumomediastinum. Five patients (0.6%) had overt pneumomediastinum and 53 patients (5.9%) had occult pneumomediastinum. Patients with occult pneumomediastinum had significantly higher ISS and AIS chest (pchest thoracostomy tube was more common (ppneumothorax. None of the patients with occult pneumomediastinum had aerodigestive tract injuries (95%CI 0-0.06). Follow up CT scan of patients with occult pneumomediastinum showed complete resolution in all cases, in average 3 h after the initial exam. Occult pneumomediastinum occurred in approximately 6% of

  5. Greater trochanteric fracture with occult intertrochanteric extension.

    Science.gov (United States)

    Reiter, Michael; O'Brien, Seth D; Bui-Mansfield, Liem T; Alderete, Joseph

    2013-10-01

    Proximal femoral fractures are frequently encountered in the emergency department (ED). Prompt diagnosis is paramount as delay will exacerbate the already poor outcomes associated with these injuries. In cases where radiography is negative but clinical suspicion remains high, magnetic resonance imaging (MRI) is the study of choice as it has the capability to depict fractures which are occult on other imaging modalities. Awareness of a particular subset of proximal femoral fractures, namely greater trochanteric fractures, is vital for both radiologists and clinicians since it has been well documented that they invariably have an intertrochanteric component which may require surgical management. The detection of intertrochanteric or cervical extension of greater trochanteric fractures has been described utilizing MRI but is underestimated with both computed tomography (CT) and bone scan. Therefore, if MRI is unavailable or contraindicated, the diagnosis of an isolated greater trochanteric fracture should be met with caution. The importance of avoiding this potential pitfall is demonstrated in the following case of an elderly woman with hip pain and CT demonstrating an isolated greater trochanteric fracture who subsequently returned to the ED with a displaced intertrochanteric fracture.

  6. Visible and occult microscopic lesions of endometriosis

    Directory of Open Access Journals (Sweden)

    Khaleque Newaz Khan

    2014-11-01

    Full Text Available Endometriosis is a multifactorial disease mostly affecting women of reproductive age and is associated with chronic pelvic pain and infertility. Even after 300 years, most of the literature claims that pathogenesis and/or pathophysiology of endometriosis is still elusive. Recurrence of pain and lesion continues to occur after effective medical or surgical therapies. Once generated within the pelvis due to retrograde entry of menstrual debris, peritoneal endometriotic lesions time-dependently change their color appearance resulting from certain biochemical change within lesions. A variable pattern of endometriotic lesions within the pelvis can be detected by laparoscopy as visible peritoneal endometriosis. It is generally believed that besides ovarian steroid hormones, the growth of endometriosis can be regulated by the innate immune system in the pelvic microenvironment by their interaction with endometrial cells and immune cells. Even with the careful eyes of an expert surgeon, we may sometimes miss detecting peritoneal lesion within the peritoneal cavity or deep into the peritoneum. In such a case, random collection of normal peritoneum may carry the possibility to identify some hidden endometriotic lesions by microscopy and these lesions can be named as occult (invisible microscopic endometriosis (OME. Here, we discuss the color appearance of peritoneal lesions and activity of these lesions by analysis of a panel of activity markers. Finally we discuss our recent findings on OME, their biological and clinical significance, and try to make a possible link in the origin between visible endometriosis and OME.

  7. Diverse Regular Employees and Non-regular Employment (Japanese)

    OpenAIRE

    MORISHIMA Motohiro

    2011-01-01

    Currently there are high expectations for the introduction of policies related to diverse regular employees. These policies are a response to the problem of disparities between regular and non-regular employees (part-time, temporary, contract and other non-regular employees) and will make it more likely that workers can balance work and their private lives while companies benefit from the advantages of regular employment. In this paper, I look at two issues that underlie this discussion. The ...

  8. Sparse structure regularized ranking

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-04-17

    Learning ranking scores is critical for the multimedia database retrieval problem. In this paper, we propose a novel ranking score learning algorithm by exploring the sparse structure and using it to regularize ranking scores. To explore the sparse structure, we assume that each multimedia object could be represented as a sparse linear combination of all other objects, and combination coefficients are regarded as a similarity measure between objects and used to regularize their ranking scores. Moreover, we propose to learn the sparse combination coefficients and the ranking scores simultaneously. A unified objective function is constructed with regard to both the combination coefficients and the ranking scores, and is optimized by an iterative algorithm. Experiments on two multimedia database retrieval data sets demonstrate the significant improvements of the propose algorithm over state-of-the-art ranking score learning algorithms.

  9. Recent progress on external occulter technology for imaging exosolar planets

    Science.gov (United States)

    Kasdin, N. J.; Vanderbei, R. J.; Sirbu, D.; Samuels, J.; Shaklan, S.; Lisman, D.; Thomson, M.; Cady, E.; Martin, S.

    Imaging planets orbiting nearby stars requires a system for suppressing the host starlight by at least ten orders of magnitude. One such approach uses an external occulter, a satellite flying far from the telescope and employing a large screen, or starshade, to suppress the incoming starlight. This trades the added complexity of building the precisely shaped starshade and flying it in formation against simplifications in the telescope since extremely precise wavefront control is no longer necessary. Much progress has been made recently in designing, testing and manufacturing starshade technology. In this paper we describe the design of starshades and report on recent accomplishments in manufacturing and measuring a prototype occulter petal as part of NASA's first Technology Development for Exoplanet Missions (TDEM) program. We demonstrate that the as-built petal is consistent with a full-size occulter achieving better than 10-10 contrast. We also discuss laboratory testing at the Princeton Occulter Testbed. These experiments use sub-scale, long-distance beam propagation to verify the diffraction analysis associated with occulter starlight suppression. We demonstrate roughly 10-10 suppression in the laboratory and discuss the important challenges and limitations.

  10. Crosslink Radio Occultation for the Remote Sensing of Planetary Atmospheres

    Science.gov (United States)

    Mannucci, A. J.; Ao, C. O.; Asmar, S.; Edwards, C. D.; Kahan, D. S.; Paik, M.; Pi, X.; Williamson, W.

    2015-12-01

    Radio occultation utilizing deep space telecommunication signals has been used with great success in the profiling of planetary atmospheres and ionospheres since the 1960s. A shortcoming of this technique, however, is the limited temporal and spatial sampling that it provides. We consider a different approach where radio occultation measurements are taken between two spacecraft orbiting an extra-terrestrial body. Such "crosslink" radio occultations between the Global Positioning System satellites and low-earth orbiting spacecraft have been routinely acquired to provide global observations of the Earth's atmosphere and ionosphere that are used for weather forecast, climate analysis, and space weather applications. The feasibility of applying this concept to other planets has recently been demonstrated for the first time, where crosslink occultation measurements have been acquired between the Mars Odyssey and Mars Reconnaissance Orbiter spacecraft. These measurements leverage the proximity link telecommunication payloads on each orbiter, which are nominally used to provide relay communication and navigation services to Mars landers and rovers. In this presentation, we will describe the Mars crosslink experiments and the corresponding data analysis in detail. In addition, we will discuss how the crosslink occultation concepts can be effectively applied in future space exploration missions.

  11. [Occultism, parapsychology and the esoteric from the perspective of psychopathology].

    Science.gov (United States)

    Scharfetter, C

    1998-10-01

    The concepts and main themes of occultism, parapsychology and esoterics are set in comparison to religion, spirituality, mysticism. The cultural relativity of these concepts is emphasised. Occultism means dealing with phenomena, processes, and/or powers which are not accessible to "normal perception". The manipulation of such powers is effected via (white, black, grey) magic. Parapsychology, in its popular sense, deals with occult phenomena, whereas scientific parapsychology investigates them empirically. Esoterics is a complex of beliefs within a hermetic tradition about occult processes and about desting after death. Transpersonal psychology deals with these issues while calling them "spiritual". Effects of paranormal experiences and actions on the side of the actor as well as the adept are discussed: personality types, interpersonal effects, crises and psychoses (mediumistic psychoses). The concept of dissociation of subpersonalities (subselves) appears to be a viable perspective to explain these phenomena. In mediumistic psychoses, the splitting of non-ego parts of the psyche leads to a manifestation of schizophrenic symptoms. Dangers for mental health are an ego inflation by self-attribution of "superhuman" power. A personality disposition for parapsychological perception and/or action may be seen in schizotypia and similar near-psychotic "personalities up the border". Adepts of occultism may present with a "false self" in the sense of Winnicott.

  12. 'Regular' and 'emergency' repair

    International Nuclear Information System (INIS)

    Luchnik, N.V.

    1975-01-01

    Experiments on the combined action of radiation and a DNA inhibitor using Crepis roots and on split-dose irradiation of human lymphocytes lead to the conclusion that there are two types of repair. The 'regular' repair takes place twice in each mitotic cycle and ensures the maintenance of genetic stability. The 'emergency' repair is induced at all stages of the mitotic cycle by high levels of injury. (author)

  13. Regularization of divergent integrals

    OpenAIRE

    Felder, Giovanni; Kazhdan, David

    2016-01-01

    We study the Hadamard finite part of divergent integrals of differential forms with singularities on submanifolds. We give formulae for the dependence of the finite part on the choice of regularization and express them in terms of a suitable local residue map. The cases where the submanifold is a complex hypersurface in a complex manifold and where it is a boundary component of a manifold with boundary, arising in string perturbation theory, are treated in more detail.

  14. Regularizing portfolio optimization

    International Nuclear Information System (INIS)

    Still, Susanne; Kondor, Imre

    2010-01-01

    The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

  15. Regularizing portfolio optimization

    Science.gov (United States)

    Still, Susanne; Kondor, Imre

    2010-07-01

    The optimization of large portfolios displays an inherent instability due to estimation error. This poses a fundamental problem, because solutions that are not stable under sample fluctuations may look optimal for a given sample, but are, in effect, very far from optimal with respect to the average risk. In this paper, we approach the problem from the point of view of statistical learning theory. The occurrence of the instability is intimately related to over-fitting, which can be avoided using known regularization methods. We show how regularized portfolio optimization with the expected shortfall as a risk measure is related to support vector regression. The budget constraint dictates a modification. We present the resulting optimization problem and discuss the solution. The L2 norm of the weight vector is used as a regularizer, which corresponds to a diversification 'pressure'. This means that diversification, besides counteracting downward fluctuations in some assets by upward fluctuations in others, is also crucial because it improves the stability of the solution. The approach we provide here allows for the simultaneous treatment of optimization and diversification in one framework that enables the investor to trade off between the two, depending on the size of the available dataset.

  16. Regular Single Valued Neutrosophic Hypergraphs

    Directory of Open Access Journals (Sweden)

    Muhammad Aslam Malik

    2016-12-01

    Full Text Available In this paper, we define the regular and totally regular single valued neutrosophic hypergraphs, and discuss the order and size along with properties of regular and totally regular single valued neutrosophic hypergraphs. We also extend work on completeness of single valued neutrosophic hypergraphs.

  17. The geometry of continuum regularization

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1987-03-01

    This lecture is primarily an introduction to coordinate-invariant regularization, a recent advance in the continuum regularization program. In this context, the program is seen as fundamentally geometric, with all regularization contained in regularized DeWitt superstructures on field deformations

  18. First operations of the SOIR occultation infrared spectrometer in Venus orbit.

    Science.gov (United States)

    Nevejans, D.; Neefs, E.; Vandaele, A. C.; Muller, C.; Fussen, D.; Berkenbosch, S.; Clairquin, R.; Korablev, O.; Federova, A.; Bertaux, J. L.

    Since May 2006, the Venus-Express spacecraft is in its nominal orbit around VENUS and the SPICAV optical package has begun to acquire spectra. The SOIR extension to SPICAV is an echelle spectrometer associated to an AOTF (Acousto-Optical Tunable Filter) for the order selection, which performs solar occultation measurements in the IR region (2.2-4.3 µm) at a resolution of 0.1 cm-1 . The detailed optical study and design as well as the manufacturing were performed at the BIRA/IASB in collaboration with its industrial partners OIP and PEDEO. It was funded by the Belgian Federal Science Policy Office under the ESA PRODEX programme. The wavelength range allows a detailed chemical inventory of the Venus atmosphere above the cloud layer with an emphasis on vertical distribution of gases. The first results look promising and will be qualitatively presented.

  19. The atmosphere of Neptune - Results of radio occultation measurements with the Voyager 2 spacecraft

    Science.gov (United States)

    Lindal, G. F.; Lyons, J. R.; Sweetnam, D. N.; Eshleman, V. R.; Hinson, D. P.

    1990-01-01

    This paper presents the vertical temperature and composition profiles of Neptune's troposphere and stratosphere, covering an altitude of 250 km, obtained from radio tracking data that were acquired during Voyager-2's occultation by Neptune, which began near 62 deg N planetographic latitude and ended near 45 deg S latitude. In the computations, the He/H2 abundance ratio 15/85 was adapted, which is consistent with solar abundance estimates and with recent results from Uranus. It was assumed that aerosols and heavier gases such as CH4, NH3, H2S, and H2O have a negligible effect on the microwave refractivity above the 0.5 bar pressure level.

  20. Operation of the Radio Occultation Mission in KOMPSAT-5

    Directory of Open Access Journals (Sweden)

    Mansoo Choi

    2010-12-01

    Full Text Available Korea multi-purpose satellite-5 (KOMPSAT-5 is a low earth orbit (LEO satellite scheduled to be launched in 2010. To satisfy the precision orbit determination (POD requirement for a high resolution synthetic aperture radar image of KOMPSAT-5, KOMPSAT-5 has atmosphere occultation POD (AOPOD system which consists of a space-borne dual frequency global positioning system (GPS receiver and a laser retro reflector array. A space-borne dual frequency GPS receiver on a LEO satellite provides position data for the POD and radio occultation data for scientific applications. This paper describes an overview of AOPOD system and operation concepts of the radio occultation mission in KOMPSAT-5. We showed AOPOD system satisfies the requirements of KOMPSAT-5 in performance and stability.

  1. Categorizing the Occult: Vodun, Sorcery and Religious Beliefs In Benin

    DEFF Research Database (Denmark)

    Strandsbjerg, Camilla

    2011-01-01

    In everyday life in Benin as well as in academic research on the topic, the terms of vodun, witchcraft and the occult are often used in a non distinct way covering quite similar phenomena while at the same time referring to different kinds of beliefs and practices. The problem of understanding...... confronted with this difficulty. Both because the vodun, as a recognized religion in the country - equal to Islam and Christianity - , plays an important role in society as well as in individual life, but also because all area of social life are on one level or another influenced by beliefs and practices...... characterized as witchcraft or occult. Reflecting upon earlier research and particularly on the choice of terminology of the occult in writing on religion and political change in Benin (PhD thesis 2008), this paper seeks to clarify some of the epistemological, academic and historical reasons that have formed...

  2. Atmospheric influences on infrared-laser signals used for occultation measurements between Low Earth Orbit satellites

    Directory of Open Access Journals (Sweden)

    S. Schweitzer

    2011-10-01

    Full Text Available LEO-LEO infrared-laser occultation (LIO is a new occultation technique between Low Earth Orbit (LEO satellites, which applies signals in the short wave infrared spectral range (SWIR within 2 μm to 2.5 μm. It is part of the LEO-LEO microwave and infrared-laser occultation (LMIO method that enables to retrieve thermodynamic profiles (pressure, temperature, humidity and altitude levels from microwave signals and profiles of greenhouse gases and further variables such as line-of-sight wind speed from simultaneously measured LIO signals. Due to the novelty of the LMIO method, detailed knowledge of atmospheric influences on LIO signals and of their suitability for accurate trace species retrieval did not yet exist. Here we discuss these influences, assessing effects from refraction, trace species absorption, aerosol extinction and Rayleigh scattering in detail, and addressing clouds, turbulence, wind, scattered solar radiation and terrestrial thermal radiation as well. We show that the influence of refractive defocusing, foreign species absorption, aerosols and turbulence is observable, but can be rendered small to negligible by use of the differential transmission principle with a close frequency spacing of LIO absorption and reference signals within 0.5%. The influences of Rayleigh scattering and terrestrial thermal radiation are found negligible. Cloud-scattered solar radiation can be observable under bright-day conditions, but this influence can be made negligible by a close time spacing (within 5 ms of interleaved laser-pulse and background signals. Cloud extinction loss generally blocks SWIR signals, except very thin or sub-visible cirrus clouds, which can be addressed by retrieving a cloud layering profile and exploiting it in the trace species retrieval. Wind can have a small influence on the trace species absorption, which can be made negligible by using a simultaneously retrieved or a moderately accurate background wind speed profile. We

  3. Presentation of Axillary Metastases from Occult Breast Carcinoma

    Institute of Scientific and Technical Information of China (English)

    Xin Wang

    2007-01-01

    Axillary presentation from occult breast cancer is uncommon and continues to be a diagnostic and therapeutic challenge to physicians.Once the diagnosis of adenocarcinoma metastatic to an axillary lymph node has been confirmed,a preoperative workup should be done.The current experience is based on several relatively small retrospective reviews and case reports.It is difficult to determine the best management of occult breast cancer.However,treatmenl of axillary Iymph node dissection is recommended for local control and complete staging information.Treatment of breast should be a choice between breast conservation with whole-breast radiotherapy and mastectomy.Adjuvant systemic treatment should be offered.

  4. Detection of occult abscesses with 111In-labeled leukocytes

    International Nuclear Information System (INIS)

    Martin, W.R.; Gurevich, N.; Goris, M.L.; McDougall, I.R.

    1979-01-01

    Clinicians are frequently faced with the problem of a patient in whom they suspect an occult abscess. In such a situation, there may be no clinical signs to localize the site of the abscess and often extensive investigations do not provide additional useful information. This report illustrates the efficacy of autologous leukocytes labeled with 111 In oxine in detecting the site and extent of occult abscesses in two patients. The technique of in vitro lebeling of leukocytes is simple and has been mastered by all of our nuclear medicine technologists

  5. Annotation of Regular Polysemy

    DEFF Research Database (Denmark)

    Martinez Alonso, Hector

    Regular polysemy has received a lot of attention from the theory of lexical semantics and from computational linguistics. However, there is no consensus on how to represent the sense of underspecified examples at the token level, namely when annotating or disambiguating senses of metonymic words...... and metonymic. We have conducted an analysis in English, Danish and Spanish. Later on, we have tried to replicate the human judgments by means of unsupervised and semi-supervised sense prediction. The automatic sense-prediction systems have been unable to find empiric evidence for the underspecified sense, even...

  6. Regularity of Minimal Surfaces

    CERN Document Server

    Dierkes, Ulrich; Tromba, Anthony J; Kuster, Albrecht

    2010-01-01

    "Regularity of Minimal Surfaces" begins with a survey of minimal surfaces with free boundaries. Following this, the basic results concerning the boundary behaviour of minimal surfaces and H-surfaces with fixed or free boundaries are studied. In particular, the asymptotic expansions at interior and boundary branch points are derived, leading to general Gauss-Bonnet formulas. Furthermore, gradient estimates and asymptotic expansions for minimal surfaces with only piecewise smooth boundaries are obtained. One of the main features of free boundary value problems for minimal surfaces is t

  7. Regularities of radiation heredity

    International Nuclear Information System (INIS)

    Skakov, M.K.; Melikhov, V.D.

    2001-01-01

    One analyzed regularities of radiation heredity in metals and alloys. One made conclusion about thermodynamically irreversible changes in structure of materials under irradiation. One offers possible ways of heredity transmittance of radiation effects at high-temperature transformations in the materials. Phenomenon of radiation heredity may be turned to practical use to control structure of liquid metal and, respectively, structure of ingot via preliminary radiation treatment of charge. Concentration microheterogeneities in material defect structure induced by preliminary irradiation represent the genetic factor of radiation heredity [ru

  8. Radio occultation studies of the Venus atmosphere with the Magellan spacecraft. 2: Results from the October 1991 experiments

    Science.gov (United States)

    Jenkins, Jon M.; Steffes, Paul G.; Hinson, David P.; Twicken, Joseph D.; Tyler, G. Leonard

    1994-01-01

    On October 5 and 6, 1991, three dual-frequency ingress radio occultation experiments were conducted at Venus during consecutive orbits of the Magellan spacecraft. The radio signals probed a region of the atmosphere near 65 deg N, with a solar zenith angle of 108 deg, reaching below 35 km at 3.6 cm, and below 34 km at 13 cm (above a mean radius of 6052 km). The high effective isotropic radiated power (EIRP) of the Magellan spacecraft and highly successful attitude maneuvers allowed these signals to probe deeper than any previous radio occultation experiment and also resulted in the most accurate thermal and sulfuric acid vapor abundance profiles ever obtained at Venus through radio occultation techniques. The performance of the spacecraft and the experiment design are discussed in an accompanying paper. Average electron density profiles retrieved from the data possess peaks between 2600 and 6000/cu cm, well below typical values of 10,000/cu cm retrieved in 1979 by Pioneer Venus at similar solar zenith angles. Other basic results include vertical profiles of temperature, pressure, and density in the neutral atmosphere, 13- and 3.6-cm absorpttivity, and H2SO4 (g) abundance below the main cloud layer. H2SO4 (g) becomes significant below 50 km, reaching peaks between 18 and 24 ppm near 39 km before dropping precipitously below 38 km. These sharp decreases confirm the thermal decomposition of sulfuric acid vapor below 39 km. Since the Venus atmosphere rotated approximately 10 deg between experiments, the data contain information about the horizontal variability of the atmosphere. All derived profiles exhibit significant variations from orbit to orbit, indicating the presence of dynamical processes between 33 and 200 km. In particular, the orbit-to-orbit variations in temperature and in H2SO4 (g) abundance appear to be correlated, suggesting that a common mechanism may be responsible for the observed spatial variations.

  9. Molecular and serological detection of occult hepatitis B virus ...

    African Journals Online (AJOL)

    hepatitis B surface antigen-negative blood donors in Malaysia. ... Objective: This study aimed to detect occult hepatitis B virus in hepatitis B surface .... of the standard HBV-positive serum and the detection ... in general population ranges from 1.5 to 9.8% but report- .... Putra, Malaysia for their financial support of this research.

  10. Occult hepatitis B among Iranian hepatitis C patients

    Directory of Open Access Journals (Sweden)

    Ahmad shavakhi

    2009-02-01

    Full Text Available

    • BACKGROUND: Occult hepatitis B is defined as presence of HBV DNA in tissue or serum without hepatitis B surface antigen. The aim of this study is to determine frequency of occult hepatitis B among hepatitis C patients in Tehran and compare the route of transmission and liver enzymes between positive and negative HBV DNA patients.
    • METHODS: In a cross sectional study, serum of 103 hepatitis C cases (79.6% men and 20.4% women were analyzed for s, x and core genes via a nested polymerase chain reaction technique.
    • RESULTS: HBV DNA was detectable in serum of 20 patients (19.4%. No significant difference in age, sex and route of transmission were seen in HBV DNA positive and negative patients. In HBV DNA positive and negative groups, mean of AST was 73, 47 (p < 0.05 and mean of ALT was 76 and 36 respectively (p < 0.05.
    • CONCLUSION: Occult hepatitis B was observed in a considerable number of hepatitis C patients in Tehran. It was associated with elevation in liver enzyme but was not related to route of transmission.
    • KEY WORD: Occult hepatitis B, hepatitis C, cirrhosis.

  11. Detection of occult HBV infection by nested PCR assay among ...

    African Journals Online (AJOL)

    Occult hepatitis B virus infection (OBI) has been reported among patients with chronic hepatitis C virus (HCV) infection and hepatocellular carcinoma (HCC). This study aimed to evaluate the prevalence of OBI in chronic hepatitis C patients with and without hepatocellular carcinoma. A total of 40 chronic hepatitis C patients ...

  12. Occult hepatitis B virus infection in immunocompromised patients

    Directory of Open Access Journals (Sweden)

    Ruth Nogueira Cordeiro Moraes Jardim

    Full Text Available Occult hepatitis B infection is characterized by hepatitis B virus (HBV DNA in the serum in the absence of hepatitis B surface antigen (HBsAg. We assessed occult HBV infection prevalence in two groups of immunocompromised patients (maintenance hemodialysis patients and HIV-positive patients presenting HBsAg-negative and anti-HBc positive serological patterns, co-infected or not by HCV. Thirty-four hemodialysis anti-HIV negative patients, 159 HIV-positive patients and 150 blood donors who were anti-HBc positive (control group were selected. HBV-DNA was detected by nested-PCR. Occult hepatitis B infection was not observed in the hemodialysis patients group but was found in 5% of the HIV-patients and in 4% of the blood donors. Immunosuppression in HIV positive patients was not a determining factor for occult HBV infection. In addition, no significant relationship between HBV-DNA and HCV co-infection in the HIV-positive patient group was found. A lack of significant associations was also observed between positivity for HBV-DNA and CD4 count, viral load and previous lamivudine treatment in these HIV-positive patients.

  13. Occult spontaneous lateral intrasphenoidal encephalocele: A rare presentation

    Directory of Open Access Journals (Sweden)

    Shahina Bano

    2013-01-01

    Full Text Available Basal encephaloceles are extremely rare congenital malformations. Advanced cross-sectional imaging modalities like computed tomography and magnetic resonance imaging are necessary for diagnosing the asymptomatic, occult basal encephalocele and planning the surgical approach. We present an interesting case of clinically silent right-sided lateral intrasphenoidal encephalocele through a large bony defect.

  14. Occurrence of occult CSF leaks during standard FESS procedures.

    Science.gov (United States)

    Bucher, S; Kugler, A; Probst, E; Epprecht, L; Stadler, R S; Holzmann, D; Soyka, M B

    2018-03-18

    To determine the incidence of occult cerebrospinal fluid leaks (CSF) after functional endoscopic sinus surgery (FESS) and to evaluate the diagnostic performance of beta2-transferrin in blood-contaminated conditions. Prospective cohort study. An analysis of 57 intraoperative samples using hydrogel 6 beta2-transferrin assay after FESS was undertaken. In case of CSF positive samples and continuing rhinorrhea, reanalysis after more than 1 year was conducted. In-vivo analysis of a primary spontaneous CSF leak sample took place to verify difficulties in detecting beta2-transferrin in blood-contaminated settings. Own titrations were performed to evaluate detection limits of CSF by beta2-transferrin and beta-trace protein assays in these settings. An incidence of 13% for occult CSF leaks after FESS was found. In blood-contaminated conditions, routine beta2-transferrin assays showed low sensitivity. In over 1 year follow-up, all samples were negative for CSF and none of them developed clinical relevant CSF leaks or meningitis. Occult and clinically irrelevant CSF leaks do occur in a significant proportion of patients during and shortly after FESS. Intra- and postoperatively, routine beta2-transferrin assays show low sensitivity. They should not be used in these settings. The clinical course of patients with occult CSF leaks indicated possibility of an uneventful follow-up.

  15. Pluto-Charon Stellar Occultation Candidates: 1990-1995

    Science.gov (United States)

    Dunham, E. W.; McDonald, S. W.; Elliot, J. L.

    1991-01-01

    We have carried out a search to identify stars that might be occulted by Pluto or Charon during the period 1990-1995 and part of 1996. This search was made with an unfiltered CCD camera operated in the strip scanning mode, and it reaches an R magnitude of approximately 17.5-about 1.5 mag fainter than previous searches. Circumstances for each of the 162 potential occultations are given, including an approximate R magnitude of the star, which allows estimation of the signal-to-noise ratio (S/N) for observation of each occultation. The faintest stars in our list would yield an S/N of about 20 for a 1 S integration when observed with a CCD detector on an 8 m telescope under a dark sky. Our astrometric precision (+/- 0.2 arcsec, with larger systematic errors possible for individual cases) is insufficient to serve as a final prediction for these potential occultations, but is sufficient to identify stars deserving of further, more accurate, astrometric observations. Statistically, we expect about 32 of these events to be observable somewhere on Earth. The number of events actually observed will be substantially smaller because of clouds and the sparse distribution of large telescopes. Finder charts for each of the 91 stars involved are presented.

  16. Radio occultation bending angle anomalies during tropical cyclones

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, S.

    2011-01-01

    -located radiosondes, climatology of tropopause altitudes and GOES analyses are also shown to support the hypothesis that the bending angle anomaly can be used as an indicator of convective towers. The results are discussed in connection to the GPS radio occultation receiver which will be part of the Atomic Clock...

  17. Past and future of radio occultation studies of planetary atmospheres

    Science.gov (United States)

    Eshleman, Von R.; Hinson, David P.; Tyler, G. Leonard; Lindal, Gunnar F.

    1987-01-01

    Measurements of radio waves that have propagated through planetary atmospheres have provided exploratory results on atmospheric constituents, structure, dynamics, and ionization for Venus, Mars, Titan, Jupiter, Saturn, and Uranus. Highlights of past results are reviewed in order to define and illustrate the potential of occultation and related radio studies in future planetary missions.

  18. A method to detect occult pneumothorax with chest radiography.

    Science.gov (United States)

    Matsumoto, Shokei; Kishikawa, Masanobu; Hayakawa, Koichi; Narumi, Atsushi; Matsunami, Katsutoshi; Kitano, Mitsuhide

    2011-04-01

    Small pneumothoraces are often not visible on supine screening chest radiographs because they develop anteriorly to the lung. These pneumothoraces are termed occult. Occult pneumothoraces account for an astonishingly high 52% to 63% of all traumatic pneumothoraces. A 19-year-old obese woman was involved in a head-on car accident. The admission anteroposterior chest radiographs were unremarkable. Because of the presence of right chest tenderness and an abrasion, we suspected the presence of a pneumothorax. Thus, we decided to take a supine oblique chest radiograph of the right side of the thorax, which clearly revealed a visceral pleural line, consistent with a diagnosis of traumatic pneumothorax. A pneumothorax may be present when a supine chest radiograph reveals either an apparent deepening of the costophrenic angle (the "deep sulcus sign") or the presence of 2 diaphragm-lung interfaces (the "double diaphragm sign"). However, in practice, supine chest radiographs have poor sensitivity for occult pneumothoraces. Oblique chest radiograph is a useful and fast screening tool that should be considered for cases of blunt chest trauma, especially when transport of critically ill patients to the computed tomographic suite is dangerous or when imminent transfer to another hospital is being arranged and early diagnosis of an occult pneumothorax is essential. Copyright © 2010 American College of Emergency Physicians. Published by Mosby, Inc. All rights reserved.

  19. Occult Metabolic Bone Disease in Chronic Pancreatitis | Hari Kumar ...

    African Journals Online (AJOL)

    Background: Chronic pancreatitis (CP) leads to malabsorption and metabolic bone disease (MBD). Alcoholic CP (ACP) and tropical CP (TCP) are the two common types of CP. Objective: We investigated the presence of occult MBD in patients with CP and compared the same between ACP and TCP. Materials and Methods: ...

  20. Effective field theory dimensional regularization

    International Nuclear Information System (INIS)

    Lehmann, Dirk; Prezeau, Gary

    2002-01-01

    A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed

  1. Effective field theory dimensional regularization

    Science.gov (United States)

    Lehmann, Dirk; Prézeau, Gary

    2002-01-01

    A Lorentz-covariant regularization scheme for effective field theories with an arbitrary number of propagating heavy and light particles is given. This regularization scheme leaves the low-energy analytic structure of Greens functions intact and preserves all the symmetries of the underlying Lagrangian. The power divergences of regularized loop integrals are controlled by the low-energy kinematic variables. Simple diagrammatic rules are derived for the regularization of arbitrary one-loop graphs and the generalization to higher loops is discussed.

  2. Sensing Water Vapon via Spacecraft Radio Occultation Observations

    Science.gov (United States)

    Kursinski, E. Robert; Hajj, George A.

    2000-01-01

    The radio occultation technique has been used to characterize planetary atmospheres since the 1960's spanning atmospheric pressures from 16 microbars to several bars. In 1988, the use of GPS signals to make occultation observations of Earth's atmosphere was realized by Tom Yunck and Gunnar Lindal at JPL. In the GPS to low-Earth-orbiter limb- viewing occultation geometry, Fresnel diffraction yield a unique combination of high vertical resolution of 100 m to 1 km at long wavelengths (approx. 20 cm) insensitive to particulate scattering which allows routine limb sounding from the lower mesosphere through the troposphere. A single orbiting GPS/GLONASS receiver can observe - 1000 to 1400 daily occultations providing as many daily, high vertical resolution soundings as the present global radiosonde network, but with far more evenly distributed, global coverage. The occultations yield profiles of refractivity as a function of height. In the cold, dry conditions of the upper troposphere and above (T less than 240 K), profiles of density, pressure (geopotential), and temperature can be derived. Given additional temperature information, water vapor can be derived in the midddle and lower troposphere with a unique combination of vertical resolution, global distribution and insensitivity to clouds and precipitation to an accuracy of approx. 0.2 g/kg. At low latitudes, moisture profiles will be accurate to 1-5% within the convective boundary layer and better than 20% below 6 to 7 km. Accuracies of climatological averages should be approx. 0. 1 g/kg limited by the biases in the temperature estimates. To use refractivity to constrain water vapor, knowledge of temperature is required. The simplest approach is to use the temperature field from an analysis such as the 6 hour ECMWF global analysis interpolated to the locations of each occultation. A better approach is to combine the temperature and moisture fields from such an analysis with the occultation refractivity in a weighting

  3. 75 FR 76006 - Regular Meeting

    Science.gov (United States)

    2010-12-07

    ... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. ACTION: Regular meeting. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held...

  4. Occult Pneumothoraces in Acute Trauma Patients

    Directory of Open Access Journals (Sweden)

    Chad Berryman

    2012-12-01

    Full Text Available Introduction: Many traumatic pneumothoraces (PTX are not seen on initial chest radiograph (CR(occult PTX but are detected only on computed tomography (CT. Although CR remains the first toolfor detecting PTX, most trauma patients with significant thoracoabdominal injuries will receive both CTand CR. The primary objective of this study was to retrospectively determine the effectiveness of CR fordetecting PTX in trauma patients. Our hypotheses were that CR is a sensitive indicator of PTX on CT,that chest pain and shortness of breath are good predictors of PTX on CR, and that we could determineother predictors of PTX on CR.Methods: All trauma patients presenting to our Level I trauma center with a CT-diagnosed PTX over a2-year period who had both a CR and a chest CT were included. The CT reading was considered thegold standard for PTX diagnosis. Electronic medical records were searched using key words fordiagnoses, symptoms, demographics, and radiologic results. We recorded the official radiologistreadings for both CR and CT (positive or negative and the size of the PTX on CT (large, moderate,small, or tiny. The outcome variable was dichotomized based on presence or absence of PTXdetected on CR. Descriptive statistics and v2 tests were used for univariate analysis. A regressionanalysis was performed to determine characteristics predictive of a PTX on CR, and 1 variable wasadded to the model for every 10 positive CRs. With equal-size groups, this study has the power of 80%to detect a 10% absolute difference in single predictors of PTX on CR with 45 subjects in each group.Results: There were 134 CT-documented PTXs included in the study. Mean age was 42, and 74%were men. For 66 (49% patients, PTX was detected on CR (sensitivity¼50%. The CR detected 30%of small PTX, 35% of moderate PTX, and 33% of large PTX. Comparing patients with and without PTXon CR, there were no significant differences in shortness of breath or chest pain. There no

  5. Occult pneumothoraces in acute trauma patients.

    Science.gov (United States)

    Ernst, Amy A; McIntyre, William A; Weiss, Steven J; Berryman, Chad

    2012-11-01

    Many traumatic pneumothoraces (PTX) are not seen on initial chest radiograph (CR) (occult PTX) but are detected only on computed tomography (CT). Although CR remains the first tool for detecting PTX, most trauma patients with significant thoracoabdominal injuries will receive both CT and CR. The primary objective of this study was to retrospectively determine the effectiveness of CR for detecting PTX in trauma patients. Our hypotheses were that CR is a sensitive indicator of PTX on CT, that chest pain and shortness of breath are good predictors of PTX on CR, and that we could determine other predictors of PTX on CR. All trauma patients presenting to our Level I trauma center with a CT-diagnosed PTX over a 2-year period who had both a CR and a chest CT were included. The CT reading was considered the gold standard for PTX diagnosis. Electronic medical records were searched using key words for diagnoses, symptoms, demographics, and radiologic results. We recorded the official radiologist readings for both CR and CT (positive or negative) and the size of the PTX on CT (large, moderate, small, or tiny). The outcome variable was dichotomized based on presence or absence of PTX detected on CR. Descriptive statistics and χ(2) tests were used for univariate analysis. A regression analysis was performed to determine characteristics predictive of a PTX on CR, and 1 variable was added to the model for every 10 positive CRs. With equal-size groups, this study has the power of 80% to detect a 10% absolute difference in single predictors of PTX on CR with 45 subjects in each group. There were 134 CT-documented PTXs included in the study. Mean age was 42, and 74% were men. For 66 (49%) patients, PTX was detected on CR (sensitivity = 50%). The CR detected 30% of small PTX, 35% of moderate PTX, and 33% of large PTX. Comparing patients with and without PTX on CR, there were no significant differences in shortness of breath or chest pain. There no relationships between PTX detected

  6. Selection of regularization parameter for l1-regularized damage detection

    Science.gov (United States)

    Hou, Rongrong; Xia, Yong; Bao, Yuequan; Zhou, Xiaoqing

    2018-06-01

    The l1 regularization technique has been developed for structural health monitoring and damage detection through employing the sparsity condition of structural damage. The regularization parameter, which controls the trade-off between data fidelity and solution size of the regularization problem, exerts a crucial effect on the solution. However, the l1 regularization problem has no closed-form solution, and the regularization parameter is usually selected by experience. This study proposes two strategies of selecting the regularization parameter for the l1-regularized damage detection problem. The first method utilizes the residual and solution norms of the optimization problem and ensures that they are both small. The other method is based on the discrepancy principle, which requires that the variance of the discrepancy between the calculated and measured responses is close to the variance of the measurement noise. The two methods are applied to a cantilever beam and a three-story frame. A range of the regularization parameter, rather than one single value, can be determined. When the regularization parameter in this range is selected, the damage can be accurately identified even for multiple damage scenarios. This range also indicates the sensitivity degree of the damage identification problem to the regularization parameter.

  7. Ensemble manifold regularization.

    Science.gov (United States)

    Geng, Bo; Tao, Dacheng; Xu, Chao; Yang, Linjun; Hua, Xian-Sheng

    2012-06-01

    We propose an automatic approximation of the intrinsic manifold for general semi-supervised learning (SSL) problems. Unfortunately, it is not trivial to define an optimization function to obtain optimal hyperparameters. Usually, cross validation is applied, but it does not necessarily scale up. Other problems derive from the suboptimality incurred by discrete grid search and the overfitting. Therefore, we develop an ensemble manifold regularization (EMR) framework to approximate the intrinsic manifold by combining several initial guesses. Algorithmically, we designed EMR carefully so it 1) learns both the composite manifold and the semi-supervised learner jointly, 2) is fully automatic for learning the intrinsic manifold hyperparameters implicitly, 3) is conditionally optimal for intrinsic manifold approximation under a mild and reasonable assumption, and 4) is scalable for a large number of candidate manifold hyperparameters, from both time and space perspectives. Furthermore, we prove the convergence property of EMR to the deterministic matrix at rate root-n. Extensive experiments over both synthetic and real data sets demonstrate the effectiveness of the proposed framework.

  8. Letter to the EditorAbel transform inversion of radio occultation measurements made with a receiver inside the Earth’s atmosphere

    Directory of Open Access Journals (Sweden)

    S. B. Healy

    2002-08-01

    Full Text Available Radio occultation measurements made with a receiver inside the Earth’s atmosphere can be inverted, assuming local spherical symmetry, with an Abel transform to provide an estimate of the atmospheric refractive index profile. The measurement geometry is closely related to problems encountered when inverting seismic time-travel data and solar occultation measurements, where the Abel solution is well known. The method requires measuring both rays that originate from above and below the local horizon of the receiver. The Abel transform operates on a profile of "partial bending angles" found by subtracting the positive elevation measurement from the negative elevation value with the same impact parameter. In principle, the refractive index profile can be derived from measurements with a single frequency GPS receiver because the ionospheric bending is removed when the partial bending angle is evaluated.Key words. Atmospheric composition and structure (pressure, density and temperature – Radio science (remote sensing

  9. Letter to the EditorAbel transform inversion of radio occultation measurements made with a receiver inside the Earth’s atmosphere

    Directory of Open Access Journals (Sweden)

    J. Haase

    Full Text Available Radio occultation measurements made with a receiver inside the Earth’s atmosphere can be inverted, assuming local spherical symmetry, with an Abel transform to provide an estimate of the atmospheric refractive index profile. The measurement geometry is closely related to problems encountered when inverting seismic time-travel data and solar occultation measurements, where the Abel solution is well known. The method requires measuring both rays that originate from above and below the local horizon of the receiver. The Abel transform operates on a profile of "partial bending angles" found by subtracting the positive elevation measurement from the negative elevation value with the same impact parameter. In principle, the refractive index profile can be derived from measurements with a single frequency GPS receiver because the ionospheric bending is removed when the partial bending angle is evaluated.Key words. Atmospheric composition and structure (pressure, density and temperature – Radio science (remote sensing

  10. NEOCE: a new external occulting coronagraph experiment for ultimate observations of the chromosphere, corona and interface

    Science.gov (United States)

    Damé, Luc; Fineschi, Silvano; Kuzin, Sergey; Von Fay-Siebenburgen, Erdélyi Robert

    Several ground facilities and space missions are currently dedicated to the study of the Sun at high resolution and of the solar corona in particular. However, and despite significant progress with the advent of space missions and UV, EUV and XUV direct observations of the hot chromosphere and million-degrees coronal plasma, much is yet to be achieved in the understanding of these high temperatures, fine dynamic dissipative structures and of the coronal heating in general. Recent missions have shown the definite role of a wide range of waves and of the magnetic field deep in the inner corona, at the chromosphere-corona interface, where dramatic and physically fundamental changes occur. The dynamics of the chromosphere and corona is controlled and governed by the emerging magnetic field. Accordingly, the direct measurement of the chromospheric and coronal magnetic fields is of prime importance. The solar corona consists of many localised loop-like structures or threads with the plasmas brightening and fading independently. The plasma evolution in each thread is believed to be related to the formation of filaments, each one being dynamic, in a non-equilibrium state. The mechanism sustaining this dynamics, oscillations or waves (Alfvén or other magneto-plasma waves), requires both very high-cadence, multi-spectral observations, and high resolution and coronal magnetometry. This is foreseen in the future Space Mission NEOCE (New External Occulting Coronagraph Experiment), the ultimate new generation high-resolution coronagraphic heliospheric mission, to be proposed for ESA M4. NEOCE, an evolution of the HiRISE mission, is ideally placed at the L5 Lagrangian point (for a better follow-up of CMEs), and provides FUV imaging and spectro-imaging, EUV and XUV imaging and spectroscopy, and ultimate coronagraphy by a remote external occulter (two satellites in formation flying 375 m apart minimizing scattered light) allowing to characterize temperature, densities and

  11. Imprint of the Sun on the Solar Wind

    Science.gov (United States)

    Woo, R.; Habbal, S. R.

    1998-01-01

    Observations of the inner corona in polarized brightness by the Mauna Loa MkIII K-coronameter and soft X-ray by Yohkoh of the inner corona are combined with Ulysses radio occultation measurements of the solar wind to demonstrate that the signature of active regions and bright points is present in the heliocentric distance range of 10-30 Ro.

  12. Adaptive Regularization of Neural Classifiers

    DEFF Research Database (Denmark)

    Andersen, Lars Nonboe; Larsen, Jan; Hansen, Lars Kai

    1997-01-01

    We present a regularization scheme which iteratively adapts the regularization parameters by minimizing the validation error. It is suggested to use the adaptive regularization scheme in conjunction with optimal brain damage pruning to optimize the architecture and to avoid overfitting. Furthermo......, we propose an improved neural classification architecture eliminating an inherent redundancy in the widely used SoftMax classification network. Numerical results demonstrate the viability of the method...

  13. Sensitivity of GPS occultation to the stratopause height

    DEFF Research Database (Denmark)

    Schrøder, Thomas Morville; Ao, Chi; de la Torre Juárez, Manuel

    2007-01-01

    We scrutinize temperature profiles collected with radio occultation measurement for an imprint of the stratopause. In the retrieval step that integrates bending angle data to atmospheric refractivity, the falloff toward infinite altitude is constrained in a boundary condition with statistical opt...... rate, not isothermal conditions. Keeping the model seed for temperature conversion to subsequent retrieval steps eliminates external information from the deconvolved refractivity. It will help argue for radio occultation as independent vehicle for climate monitoring....... height gradient. On the basis of noise free simulation using a climatology covering all latitudes, seasons, and hours and on the basis of validation against data collected with weather balloons, laser imaging, and limb sounding, we find that adaptation to the fluctuating stratopause is crucial...

  14. Dusty Dwarfs Galaxies Occulting A Bright Background Spiral

    Science.gov (United States)

    Holwerda, Benne

    2017-08-01

    The role of dust in shaping the spectral energy distributions of low mass disk galaxies remains poorly understood. Recent results from the Herschel Space Observatory imply that dwarf galaxies contain large amounts of cool (T 20K) dust, coupled with very modest optical extinctions. These seemingly contradictory conclusions may be resolved if dwarfs harbor a variety of dust geometries, e.g., dust at larger galactocentric radii or in quiescent dark clumps. We propose HST observations of six truly occulting dwarf galaxies drawn from the Galaxy Zoo catalog of silhouetted galaxy pairs. Confirmed, true occulting dwarfs are rare as most low-mass disks in overlap are either close satellites or do not have a confirmed redshift. Dwarf occulters are the key to determining the spatial extent of dust, the small scale structure introduced by turbulence, and the prevailing dust attenuation law. The recent spectroscopic confirmation of bona-fide low mass occulting dwarfs offers an opportunity to map dust in these with HST. What is the role of dust in the SED of these dwarf disk galaxies? With shorter feedback scales, how does star-formation affect their morphology and dust composition, as revealed from their attenuation curve? The resolution of HST allows us to map the dust disks down to the fine scale structure of molecular clouds and multi-wavelength imaging maps the attenuation curve and hence dust composition in these disks. We therefore ask for 2 orbits on each of 6 dwarf galaxies in F275W, F475W, F606W, F814W and F125W to map dust from UV to NIR to constrain the attenuation curve.

  15. [Occult pneumothorax: Does it take drain before elective surgery?].

    Science.gov (United States)

    Bensghir, M; Moutaoukil, M; Meziane, M; Jaafari, A; Hemmaoui, B; Haimeur, C

    2016-08-01

    Pneumothorax occult is defined by the presence of a non-visible to standard asymptomatic pneumothorax and pulmonary diagnosed only by X-ray computed tomography. The presence of this type of pneumothorax before planned surgery is a rare situation. What to do remains non-consensual. Through two clinic cases and a literature review, the authors discuss the modalities of management of this entity. Copyright © 2016 Elsevier Masson SAS. All rights reserved.

  16. Implementation of immunochemical faecal occult blood test in general practice

    DEFF Research Database (Denmark)

    Juul, Jakob Søgaard; Bro, Flemming; Hornung, Nete

    2016-01-01

    anvendelsen af immunochemical faecal occult blood test (iFOBT) i almen praksis. iFOBT detekterer humant globin i fæces og indikerer gastrointestinal blødning. Studiet udgør en del af et ph.d.-studie, der bidrager med ny viden til at optimere udredningen af patienter med tarmkræft. Der er et stort behov...

  17. [Results of conservative treatment in patients with occult pneumothorax].

    Science.gov (United States)

    Llaquet Bayo, Heura; Montmany Vioque, Sandra; Rebasa, Pere; Navarro Soto, Salvador

    2016-04-01

    An occult pneumothorax is found in 2-15% trauma patients. Observation (without tube thoracostomy) in these patients presents still some controversies in the clinical practice. The objective of the study is to evaluate the efficacy and the adverse effects when observation is performed. A retrospective observational study was undertaken in our center (university hospital level II). Data was obtained from a database with prospective registration. A total of 1087 trauma patients admitted in the intensive care unit from 2006 to 2013 were included. In this period, 126 patients with occult pneumothorax were identified, 73 patients (58%) underwent immediate tube thoracostomy and 53 patients (42%) were observed. Nine patients (12%) failed observation and required tube thoracostomy for pneumothorax progression or hemothorax. No patient developed a tension pneumothorax or experienced another adverse event related to the absence of tube thoracostomy. Of the observed patients 16 were under positive pressure ventilation, in this group 3 patients (19%) failed observation. There were no differences in mortality, hospital length of stay or intensive care length of stay between the observed and non-observed group. Observation is a safe treatment in occult pneumothorax, even in pressure positive ventilated patients. Copyright © 2014 AEC. Publicado por Elsevier España, S.L.U. All rights reserved.

  18. Lunar occultation observation of μ Sgr: A progress report

    Energy Technology Data Exchange (ETDEWEB)

    Jatmiko, A. T. P. [Bosscha Observatory, Institut Teknologi Bandung (Indonesia); Puannandra, G. P.; Hapsari, R. D.; Putri, R. A.; Arifin, Z. M.; Haans, G. K.; Hadiputrawan, I. P. W. [Bosscha Observatory, Institut Teknologi Bandung, Indonesia and Astronomy Study Program, Institut Teknologi Bandung (Indonesia)

    2014-03-24

    Lunar Occultation (LO) is an event where limb of the Moon passing over a particular heavenly bodies such as stars, asteroids, or planets. In other words, during the event, stars, asteroids and planets are occulted by the Moon. When occulted objects contact the lunar limb, there will be a diffraction fringe(s) which can be measured photometrically, until the signal vanishes into noise. This event will give us a valuable information about binarities (of stars) and/or angular diameters estimation (of stars, planets, asteroids) in milliarcsecond resolution, by fitting with theoretical LO pattern. CCDs are common for LO observation because of its fast read out, and recently are developed for sub-meter class telescope. In this paper, our LO observation attempt of μ Sgr and its progress report are presented. The observation was conducted on July 30{sup th}, 2012 at Bosscha Observatory, Indonesia, using 45cm f/12 GOTO telescope combined with ST-9 XE CCD camera and Bessel B filter. We used drift-scan method to obtain light curve of the star as it was disappearing behind Moon's dark limb. Our goal is to detect binarity (or multiplicity) of this particular object.

  19. Developing an Optical Lunar Occultation Measurement Reduction System for Observations at Kaau Observatory

    Science.gov (United States)

    Malawi, Abdulrahman A.

    2013-06-01

    We present here a detailed explanation of the reduction method that we use to determine the angular diameters of the stars occulted by the dark limb of the moon. This is a main part of the lunar occultation observation program running at King Abdul Aziz University observatory since late 1993. The process is based on the least square model fitting method of analyzing occultation data, first introduced by Nather et al. (Astron. J. 75:963, 1970).

  20. Lunar occultation of Saturn. IV - Astrometric results from observations of the satellites

    Science.gov (United States)

    Dunham, D. W.; Elliot, J. L.

    1978-01-01

    The method of determining local lunar limb slopes, and the consequent time scale needed for diameter studies, from accurate occultation timings at two nearby telescopes is described. Results for photoelectric observations made at Mauna Kea Observatory during the occultation of Saturn's satellites on March 30, 1974, are discussed. Analysis of all observations of occultations of Saturn's satellites during 1974 indicates possible errors in the ephemerides of Saturn and its satellites.

  1. Diagnostic accuracy of oblique chest radiograph for occult pneumothorax: comparison with ultrasonography

    OpenAIRE

    Matsumoto, Shokei; Sekine, Kazuhiko; Funabiki, Tomohiro; Orita, Tomohiko; Shimizu, Masayuki; Hayashida, Kei; Kazamaki, Taku; Suzuki, Tatsuya; Kishikawa, Masanobu; Yamazaki, Motoyasu; Kitano, Mitsuhide

    2016-01-01

    Backgraound An occult pneumothorax is a pneumothorax that is not seen on a supine chest X-ray but is detected by computed tomography scanning. However, critical patients are difficult to transport to the computed tomography suite. We previously reported a method to detect occult pneumothorax using oblique chest radiography (OXR). Several authors have also reported that ultrasonography is an effective technique for detecting occult pneumothorax. The aim of this study was to evaluate the useful...

  2. 75 FR 53966 - Regular Meeting

    Science.gov (United States)

    2010-09-02

    ... FARM CREDIT SYSTEM INSURANCE CORPORATION Regular Meeting AGENCY: Farm Credit System Insurance Corporation Board. SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). DATE AND TIME: The meeting of the Board will be held at the offices of the Farm...

  3. Online co-regularized algorithms

    NARCIS (Netherlands)

    Ruijter, T. de; Tsivtsivadze, E.; Heskes, T.

    2012-01-01

    We propose an online co-regularized learning algorithm for classification and regression tasks. We demonstrate that by sequentially co-regularizing prediction functions on unlabeled data points, our algorithm provides improved performance in comparison to supervised methods on several UCI benchmarks

  4. Continuum-regularized quantum gravity

    International Nuclear Information System (INIS)

    Chan Huesum; Halpern, M.B.

    1987-01-01

    The recent continuum regularization of d-dimensional Euclidean gravity is generalized to arbitrary power-law measure and studied in some detail as a representative example of coordinate-invariant regularization. The weak-coupling expansion of the theory illustrates a generic geometrization of regularized Schwinger-Dyson rules, generalizing previous rules in flat space and flat superspace. The rules are applied in a non-trivial explicit check of Einstein invariance at one loop: the cosmological counterterm is computed and its contribution is included in a verification that the graviton mass is zero. (orig.)

  5. Solar irridiance variations and solar activity

    International Nuclear Information System (INIS)

    Willson, R.C.

    1982-01-01

    A mean value for the 1 AU total solar irradiance of 1368.2 W/m 2 and a downward trend of 0.05% per year were derived from measurements by the Active Cavity Radiometer Irradiance Monitor (ACRIM) experiment on the Solar Maximum Mission during 1980. Distinct temporary solar irradiance decreases associated with solar activity maxima were observed with a series of nine dips from April to October recurring at fairly regular intervals averaging 24 days. The decreases correlate inversely with sunspot area, 2800-MHz flux, and Zurich sunspot number. Dominant periods common to the irradiance and sunspot area power spectra link the irradiance decreases to sunspot flux deficit in solar active regions. Evidence of significant total irradiance modulation by facular flux excess is cited. A persistent radiative cycle of active regions consistent with the ACRIM irradiance results and the morphology of solar active regions was found. The pattern of regularly recurrent active region maxima between April and October suggests an asymmetry in solar activity generation during this period

  6. New regular black hole solutions

    International Nuclear Information System (INIS)

    Lemos, Jose P. S.; Zanchin, Vilson T.

    2011-01-01

    In the present work we consider general relativity coupled to Maxwell's electromagnetism and charged matter. Under the assumption of spherical symmetry, there is a particular class of solutions that correspond to regular charged black holes whose interior region is de Sitter, the exterior region is Reissner-Nordstroem and there is a charged thin-layer in-between the two. The main physical and geometrical properties of such charged regular black holes are analyzed.

  7. Regular variation on measure chains

    Czech Academy of Sciences Publication Activity Database

    Řehák, Pavel; Vitovec, J.

    2010-01-01

    Roč. 72, č. 1 (2010), s. 439-448 ISSN 0362-546X R&D Projects: GA AV ČR KJB100190701 Institutional research plan: CEZ:AV0Z10190503 Keywords : regularly varying function * regularly varying sequence * measure chain * time scale * embedding theorem * representation theorem * second order dynamic equation * asymptotic properties Subject RIV: BA - General Mathematics Impact factor: 1.279, year: 2010 http://www.sciencedirect.com/science/article/pii/S0362546X09008475

  8. Manifold Regularized Correlation Object Tracking

    OpenAIRE

    Hu, Hongwei; Ma, Bo; Shen, Jianbing; Shao, Ling

    2017-01-01

    In this paper, we propose a manifold regularized correlation tracking method with augmented samples. To make better use of the unlabeled data and the manifold structure of the sample space, a manifold regularization-based correlation filter is introduced, which aims to assign similar labels to neighbor samples. Meanwhile, the regression model is learned by exploiting the block-circulant structure of matrices resulting from the augmented translated samples over multiple base samples cropped fr...

  9. On geodesics in low regularity

    Science.gov (United States)

    Sämann, Clemens; Steinbauer, Roland

    2018-02-01

    We consider geodesics in both Riemannian and Lorentzian manifolds with metrics of low regularity. We discuss existence of extremal curves for continuous metrics and present several old and new examples that highlight their subtle interrelation with solutions of the geodesic equations. Then we turn to the initial value problem for geodesics for locally Lipschitz continuous metrics and generalize recent results on existence, regularity and uniqueness of solutions in the sense of Filippov.

  10. Condition Number Regularized Covariance Estimation.

    Science.gov (United States)

    Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

    2013-06-01

    Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the "large p small n " setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required.

  11. Condition Number Regularized Covariance Estimation*

    Science.gov (United States)

    Won, Joong-Ho; Lim, Johan; Kim, Seung-Jean; Rajaratnam, Bala

    2012-01-01

    Estimation of high-dimensional covariance matrices is known to be a difficult problem, has many applications, and is of current interest to the larger statistics community. In many applications including so-called the “large p small n” setting, the estimate of the covariance matrix is required to be not only invertible, but also well-conditioned. Although many regularization schemes attempt to do this, none of them address the ill-conditioning problem directly. In this paper, we propose a maximum likelihood approach, with the direct goal of obtaining a well-conditioned estimator. No sparsity assumption on either the covariance matrix or its inverse are are imposed, thus making our procedure more widely applicable. We demonstrate that the proposed regularization scheme is computationally efficient, yields a type of Steinian shrinkage estimator, and has a natural Bayesian interpretation. We investigate the theoretical properties of the regularized covariance estimator comprehensively, including its regularization path, and proceed to develop an approach that adaptively determines the level of regularization that is required. Finally, we demonstrate the performance of the regularized estimator in decision-theoretic comparisons and in the financial portfolio optimization setting. The proposed approach has desirable properties, and can serve as a competitive procedure, especially when the sample size is small and when a well-conditioned estimator is required. PMID:23730197

  12. Geometry of solar corona expansion and solar wind parameters

    International Nuclear Information System (INIS)

    Krajnev, M.B.

    1980-01-01

    The character of the parameter chanqe of solar wind plasma in the region of the Earth orbit is studied. The main regularities in the parametep behaviour of solar wind (plasma velocity and density) are qualitatively explained in the framework of a model according to which solar corona expansion stronqly differs from radial expansion, that is: the solar wind current lines are focused towards helioequator during the period of low solar activity with gradual transfer to radial expansion during the years of high solar activity. It is shown that the geometry of the solar wind current tubes and its change with the solar activity cycle can not serve an explanation of the observed change of the solar wind parameters

  13. [Management of occult malformations at the lateral skull base].

    Science.gov (United States)

    Bryson, E; Draf, W; Hofmann, E; Bockmühl, U

    2005-12-01

    Occult malformations of the lateral skull base are rare anomalies, but can cause severe complications such as recurrent meningitis. Therefore, they need to be precisely delineated and sufficient surgical closure is mandatory. Between 1986 and 2004 twenty patients (10 children and 10 adults) with occult malformations at the lateral skull base were treated surgically at the ENT-Department of the Hospital Fulda gAG. Of these 3 Mondini-malformations, 11 defects of the tegmen tympani or the mastoidal roof, 2 dural lesions to the posterior fossa and 4 malformations within the pyramidal apex have been found. Four patients have had multiple anomalies. Routing symptom was in all cases at least one previous meningitis. Radiological diagnostics included high-resolution computed tomography (CT) and magnetic resonance imaging (MRI) as well as CT- or MR-cisternography. Depending on type and localisation of the defect the following surgical algorithm was carried out: The trans-mastoidal approach was used in all cases of Mondini-malformation (including obliteration of the ear), in case of lesions to the posterior fossa as well as partly in anomalies at the tegmen tympani and mastoidal roof, respectively. Defects of the pyramidal apex should be explored via the trans-mastoidal way if the lesion is located caudally to the inner auditory canal (IAC), whereas the trans-temporal approach should be used if the lesion is situated ventral to the IAC and dorso-medially to the internal carotid artery (ICA). The trans-temporal approach was also performed in large defects of the tegmen tympani and mastoidal roof as well as in recurrences. In all cases of recurrent meningitis caused by agents of the upper airway tract the basic principle should be to search for occult skull base malformations radiologically as well as by sodium fluorescein endoscopy as long as the anomaly is detected.

  14. A 2017 stellar occultation by Orcus/Vanth

    Science.gov (United States)

    Sickafoose, Amanda A.; Bosh, Amanda S.; Levine, Stephen; Zuluaga, Carlos A.; Genade, Anja; Schindler, Karsten; Lister, Tim; Person, Michael J.

    2017-10-01

    (90482) Orcus is a large trans-Neptunian object (TNO) of diameter ~900 km, located in the 3:2 orbital resonance with Neptune. This plutino has a satellite, Vanth, approximately 280 km in diameter. Vanth orbits roughly 9000 km from Orcus in a ~9.5-day period. This system is particularly interesting, as Orcus falls between the small, spectrally-bland TNOs and the large TNOs having spectra rich in volatile features, while Vanth might have resulted from either collision or capture.A stellar occultation by Orcus was predicted to occur on 07 March 2017. Observations were made from five sites: the 0.6-m Astronomical Telescope of the University of Stuttgart (ATUS) at Sierra Remote Observatories (SRO), California; Las Cumbres Observatory’s 1-m telescope (ELP) at McDonald Observatory, Fort Davis, Texas; NASA’s 3-m InfraRed Telescope Facility (IRTF) on Mauna Kea, Hawaii; the 4.1-m Southern Astrophysical Research telescope (SOAR) on Cerro Pachón, Chile; and the 0.6-m Southeastern Association for Research in Astronomy telescope (SARA-CT) at Cerro Tololo, Chile. High-speed, visible-wavelength images were taken at all sites, in addition to simultaneous K-band images at the IRTF. A solid-body occultation was observed at both ELP and the IRTF. Offset midtimes and incompatible light ratios suggest that two different stars were occulted by two different bodies, likely Orcus and Vanth. See Bosh et al. this conference for details of the astrometry for the event. Here, we present results from the observations, including light curves, size and albedo estimates, and upper limits on a possible atmosphere.

  15. External occulter edge scattering control using metamaterials for exoplanet detection

    Science.gov (United States)

    Bendek, Eduardo A.; Sirbu, Dan; Liu, Zhaowei; Martin, Stefan; Lu, Dylan

    2015-09-01

    Direct imaging of earth-like exoplanets in the Habitable Zone of sun-like stars requires image contrast of ~10^10 at angular separations of around a hundred milliarcseconds. One approach for achieving this performance is to fly a starshade at a long distance in front of the telescope, shading the telescope from the direct starlight, but allowing planets around the star to be seen. The starshade is positioned so that sunlight falls on the surface away from the telescope, so the sun does not directly illuminate it. However, sunlight scattered from the starshade edge can enter the telescope, raising the background light level and potentially preventing the starshade from delivering the required contrast. As a result, starshade edge design has been identified as one of the highest priority technology gaps for external occulter missions in the NASAs Exoplanet Exploration Program Technology Plan 2013. To reduce the sunlight edge scatter to an acceptable level, the edge Radius Of Curvature (ROC) should be 1μm or less (commercial razor blades have ROC of a few hundred nanometer). This poses a challenging manufacturing requirement and may make the occulter difficult to handle. In this paper we propose an alternative approach to controlling the edge scattering by applying a flexible metamaterial to the occulter edge. Metamaterials are artificially structured materials, which have been designed to display properties not found in natural materials. Metamaterials can be designed to direct the scatter at planned incident angles away from the space telescope, thereby directly decreasing the contaminating background light. Reduction of the background light translates into shorter integration time to characterize a target planet and therefore improves the efficiency of the observations. As an additional benefit, metamaterials also have potential to produce increased tolerance to edge defects.

  16. Multiple surface antigen mutations in five blood donors with occult hepatitis B virus infection

    NARCIS (Netherlands)

    Zaaijer, H. L.; Torres, P.; Ontañón, A.; Ponte, L. González; Koppelman, M. H. G. M.; Lelie, P. N.; Hemert, F. J. van; Boot, H. J.

    2008-01-01

    Occult hepatitis B virus (HBV) infection is characterized by the presence of HBV DNA while the HBV surface antigen (HBsAg) remains undetectable. The HBV genomes in five asymptomatic blood donors with occult HBV infection and low viremia ( <10 to 1,000 HBV DNA copies/mL, genotype D) were studied. An

  17. Trio of Stellar Occultations by Pluto One Year Prior to New Horizons’ Arrival

    Science.gov (United States)

    2016-04-02

    stellar signal, both with 20 s exposures with our frame-transfer Portable Occultation, Eclipse, and Transit System. Since Pluto had a geocentric velocity...and for New Horizons’s 2015 approach . For the July 31 event, though for our atmospheric studies we are glad to have detected the occultation of this

  18. Spectral irradiance curve calculations for any type of solar eclipse

    International Nuclear Information System (INIS)

    Deepak, A.; Merrill, J.E.

    1974-01-01

    A simple procedure is described for calculating the eclipse function (EF), alpha, and hence the spectral irradiance curve (SIC), (1-alpha), for any type of solar eclipse: namely, the occultation (partial/total) eclipse and the transit (partial/annular) eclipse. The SIC (or the EF) gives the variation of the amount (or the loss) of solar radiation of a given wavelength reaching a distant observer for various positions of the moon across the sun. The scheme is based on the theory of light curves of eclipsing binaries, the results of which are tabulated in Merrill's Tables, and is valid for all wavelengths for which the solar limb-darkening obeys the cosine law: J = /sub c/(1 - X + X cost gamma). As an example of computing the SIC for an occultation eclipse which may be total, the calculations for the March 7, 1970, eclipse are described in detail. (U.S.)

  19. Combined parathyroid adenoma and an occult papillary carcinoma

    International Nuclear Information System (INIS)

    Meshikhes, Abdul-Wahid N.; Al-Saihati, Basima A.; Butt, Mohammad S.

    2004-01-01

    Although the pathological association of thyroid and parathyroid disease is common, the association of both parathyroid adenoma and thyroid cancer is rare. We report here a case of a 45-year-old saudi women who diagnosed to have primary hyperparathyrodism due to single parathyroid adenoma as confirmed biochemically and radiologically. At operation, the adenoma was found to be an intrathyroid and therefore a thyroid lobectomy was performed. Histology of the excised lobe revealed in addition to the intrathyroid parathyroid adenoma a concurrent occult thyroid papillary carcinoma. The interesting association is discussed based on a literature review. (author)

  20. MR imaging of occult fractures of the knee

    International Nuclear Information System (INIS)

    Mink, J.H.; Deutsch, A.L.

    1988-01-01

    The authors encountered 65 radiographically occult fractures that they classified into five types. Bone bruises were a result of direct trauma or were associated with ligamentous injury. They were characterized by geographic foci of decreased signal on short repetition time (TR), short echo time (TE) sequences. Stress fractures were linear or globular foci of low signal on short TR, short TE sequences. Osteochondral fractures were displaced or impacted types; the latter were often associated with an anterior cruciate ligament tear. Tibial fractures were minimally displaced, vertically oriented fractures extending into the plateaus. Femoral fractures were Y-shaped, extending across the supracondylar region

  1. Laser fluorescence bronchoscope for localization of occult lung tumors

    International Nuclear Information System (INIS)

    Profio, A.E.; Doiron, D.R.; King, E.G.

    1979-01-01

    A system for imaging occult bronchogenic carcinoma by the fluorescence of previously-injected, tumor-specific compound hematoporphyrin-derivative has been assembled and successfully used to locate a tumor l mm thick. The violet excitation source is a krypton ion laser coupled to fused quartz fiber light conductor. An electrostatic image intensifier attached to a standard flexible fiberoptic bronchoscope provides a bright image even at relatively low irradiance. A red secondary filter rejects most reflected background and autofluorescence. Sensitivity and contrast capability of the system should permit detection of a tumor less than 0.1 mm thick

  2. Occult microscopic endometriosis: undetectable by laparoscopy in normal peritoneum.

    Science.gov (United States)

    Khan, Khaleque Newaz; Fujishita, Akira; Kitajima, Michio; Hiraki, Koichi; Nakashima, Masahiro; Masuzaki, Hideaki

    2014-03-01

    Is there any occurrence of hidden (occult) endometriotic lesions in normal peritoneum of women with and without visible endometriosis? We detected a slightly higher occurrence of occult microscopic endometriosis (OME) in normal peritoneum of women with visible endometriosis than in control women. Based on a small number of cases, the concept of invisible microscopic endometriosis in visually normal peritoneum has been reported for more than a decade but there is controversy regarding their tissue activity and clinical significance. This case-controlled research study was conducted with prospectively collected normal peritoneal samples from 151 women with and 62 women without visible endometriosis. Normal peritoneal biopsy specimens from different pelvic sites of were collected during laparoscopy. A histological search of all peritoneal biopsy specimens for the detection of invisible endometriosis was done by immunoreaction to Ber-EP4 (epithelial cell marker), CD10 (stromal cell marker) and Calretinin (mesothelial cell marker). Tissue expression of estrogen/progesterone receptors (ER/PR) and cell proliferation marker, Ki-67, was performed by immunohistochemistry to identify tissue activity. Three different patterns of OME were detected based on (I) the presence of typical gland/stroma, (II) reactive hyperplastic change of endometrioid epithelial cells with surrounding stroma and (III) single-layered epithelium-lined cystic lesions with surrounding stroma. A higher tendency toward the occurrence of OME was found in women with visible endometriosis (15.2%, 23/151) compared with control women (6.4%, 4/62) (P = 0.06, χ(2) test). The epithelial cells and/or stromal cells of OME lesions were immunoreactive to Ber-EP4 and CD10 but not reactive to Calretinin. ER and PR expression was observed in all patterns of OME lesions. Ki-67 index was significantly higher in pattern I/II OME lesions than in pattern III OME lesions (Pendometriosis due to the presence of adhesions in

  3. Significance of mammographic signs in clinically occult disease

    Energy Technology Data Exchange (ETDEWEB)

    Waal, J.C. de; Steil, B.; Baltzer, J.; Vaillant, W.; Zander, J.

    1987-10-01

    The significance of various radiographic signs in 183 patients with clinically occult breast disease is described. 30.6% hat a carcinoma of the breast or a carcinoma in situ. The radiological features have varying predictive values and there is variation in the incidence of lymph node metastases. It is considered useful to classify the radiological appearances under the headings of round foci, star-shaped opacities, diffuse opacities, opacities with calcification and groups of micro-calcification. Despite the early diagnosis, 24% of patients already had lymph node metastases.

  4. Occult lung malignancy presenting with finger pain: a case report

    Directory of Open Access Journals (Sweden)

    Embley Matthew A

    2008-12-01

    Full Text Available Abstract Introduction Lung cancer is currently one of the most common malignancies in the world. Early detection is an important prognostic factor. Unfortunately, initial symptoms may be vague and a substantial proportion of cases present with the effects of metastases. Case presentation We discuss a case of occult lung malignancy in a 61-year-old man. The only symptom at presentation was pain in the right ring finger due to metastasis from the lung primary. Conclusion This case highlights the need for vigilance when a patient presents with unusual or unexplained symptoms, especially if they have known risk factors for cancer.

  5. Geometric continuum regularization of quantum field theory

    International Nuclear Information System (INIS)

    Halpern, M.B.

    1989-01-01

    An overview of the continuum regularization program is given. The program is traced from its roots in stochastic quantization, with emphasis on the examples of regularized gauge theory, the regularized general nonlinear sigma model and regularized quantum gravity. In its coordinate-invariant form, the regularization is seen as entirely geometric: only the supermetric on field deformations is regularized, and the prescription provides universal nonperturbative invariant continuum regularization across all quantum field theory. 54 refs

  6. Wave propagation simulation of radio occultations based on ECMWF refractivity profiles

    DEFF Research Database (Denmark)

    von Benzon, Hans-Henrik; Høeg, Per

    2015-01-01

    This paper describes a complete radio occultation simulation environment, including realistic refractivity profiles, wave propagation modeling, instrument modeling, and bending angle retrieval. The wave propagator is used to simulate radio occultation measurements. The radio waves are propagated...... of radio occultations. The output from the wave propagator simulator is used as input to a Full Spectrum Inversion retrieval module which calculates geophysical parameters. These parameters can be compared to the ECMWF atmospheric profiles. The comparison can be used to reveal system errors and get...... a better understanding of the physics. The wave propagation simulations will in this paper also be compared to real measurements. These radio occultations have been exposed to the same atmospheric conditions as the radio occultations simulated by the wave propagator. This comparison reveals that precise...

  7. PREVALENCE OF OCCULT DEPRESSION IN ELDERLY WITH CHRONIC CO - MORBIDS

    Directory of Open Access Journals (Sweden)

    Sachin

    2015-02-01

    Full Text Available BACKGROUND: Growth in elderly population has led to an increase in age related diseases and mainly depression which is affecting the quality of life. Depression is more prevalent amongst elderly individuals with medical illnesses and emerging public health problem leading to increased morbidity and disability worldwide. AIMS AND OBJE CTIVES: To assess the prevalence of occult depression in elderly patients with chronic co - morbid medical conditions. MATERIALS AND METHODS: It was a cross - sectional study conducted in tertiary hospital. Total 100 elderly patients with underlying chronic me dical illnesses were included. Depression in study population was assessed by geriatric depression scale and analyzed. RESULT: Out of 100 patients 23(23% had depression. Females 12/39(30.76% were affected more than males 11/61 (18.03%. Depression was mo re prevalent among patients with 3 or more co - morbid conditions (45.4% as compared to <3 (11.9%. CONCLUSION: Elderly patients with multiple chronic medical illnesses may have associated occult depression. Screening of these patients for depression couple d with appropriate psychiatric referral should be an integral part of Geriatric service

  8. Fluctuations of radio occultation signals in sounding the Earth's atmosphere

    Directory of Open Access Journals (Sweden)

    V. Kan

    2018-02-01

    Full Text Available We discuss the relationships that link the observed fluctuation spectra of the amplitude and phase of signals used for the radio occultation sounding of the Earth's atmosphere, with the spectra of atmospheric inhomogeneities. Our analysis employs the approximation of the phase screen and of weak fluctuations. We make our estimates for the following characteristic inhomogeneity types: (1 the isotropic Kolmogorov turbulence and (2 the anisotropic saturated internal gravity waves. We obtain the expressions for the variances of the amplitude and phase fluctuations of radio occultation signals as well as their estimates for the typical parameters of inhomogeneity models. From the GPS/MET observations, we evaluate the spectra of the amplitude and phase fluctuations in the altitude interval from 4 to 25 km in the middle and polar latitudes. As indicated by theoretical and experimental estimates, the main contribution into the radio signal fluctuations comes from the internal gravity waves. The influence of the Kolmogorov turbulence is negligible. We derive simple relationships that link the parameters of internal gravity waves and the statistical characteristics of the radio signal fluctuations. These results may serve as the basis for the global monitoring of the wave activity in the stratosphere and upper troposphere.

  9. Progress in turbulence detection via GNSS occultation data

    Directory of Open Access Journals (Sweden)

    L. B. Cornman

    2012-04-01

    Full Text Available The increased availability of radio occultation (RO data offers the ability to detect and study turbulence in the Earth's atmosphere. An analysis of how RO data can be used to determine the strength and location of turbulent regions is presented. This includes the derivation of a model for the power spectrum of the log-amplitude and phase fluctuations of the permittivity (or index of refraction field. The bulk of the paper is then concerned with the estimation of the model parameters. Parameter estimators are introduced and some of their statistical properties are studied. These estimators are then applied to simulated log-amplitude RO signals. This includes the analysis of global statistics derived from a large number of realizations, as well as case studies that illustrate various specific aspects of the problem. Improvements to the basic estimation methods are discussed, and their beneficial properties are illustrated. The estimation techniques are then applied to real occultation data. Only two cases are presented, but they illustrate some of the salient features inherent in real data.

  10. Influence of Ionospheric Weather on GNSS Radio Occultation Signals

    Science.gov (United States)

    Yue, X.; Schreiner, W. S.; Pedatella, N. M.; Kuo, Y. H.

    2016-12-01

    Transient loss of lock (LOL) is one of the key space weather effects on the Global Navigation Satellite System (GNSS). Based on the Constellation Observing System for Meteorology, Ionosphere, and Climate (COSMIC) Global Positioning System (GPS) radio occultation (RO) observations during 2007-2011, we have analyzed the signal cycle slip (CS) occurrence comprehensively and its correlation to the ionospheric weather phenomena such as sporadic E (Es), equatorial F region irregularity (EFI), and the ionospheric equatorial ionization anomaly (EIA). The high vertical resolution of RO observations enables us to distinguish the CS resulting from different ionospheric layers clearly on a global scale. In the E layer, the CS is dominated by the Es occurrence, while in the F layer, the CS is mainly related to the EIA and EFI at low and equatorial latitudes. In the polar region, the CS is primarily related to polar cap electron density gradients. The overall average CS (> 6 cycles) occurrence is 23% per occultation, with the E (50-150 km) and F (150-600 km) layers contributing 8.3% and 14.7%, respectively. Awareness of the effect of the ionospheric weather on the CS of the low-Earth-orbit (LEO)-based GNSS signal could be beneficial to a variety of applications, including the LEO-based GNSS data processing and the corresponding hardware/firmware design.

  11. Occulting Light Concentrators in Liquid Scintillator Neutrino Detectors

    Science.gov (United States)

    Buizza Avanzini, Margherita; Cabrera, Anatael; Dusini, Stefano; Grassi, Marco; He, Miao; Wu, Wenjie

    2017-09-01

    The experimental efforts characterizing the era of precision neutrino physics revolve around collecting high-statistics neutrino samples and attaining an excellent energy and position resolution. Next generation liquid-based neutrino detectors, such as JUNO, HyperKamiokande, etc, share the use of a large target mass, and the need of pushing light collection to the edge for maximal calorimetric information. Achieving high light collection implies considerable costs, especially when considering detector masses of several kt. A traditional strategy to maximize the effective photo-coverage with the minimum number of PMTs relies on Light Concentrators (LC), such as Winston Cones. In this paper, the authors introduce a novel concept called Occulting Light Concentrators (OLC), whereby a traditional LC gets tailored to a conventional PMT, by taking into account its single-photoelectron collection efficiency profile and thus occulting the worst performing portion of the photocathode. Thus, the OLC shape optimization takes into account not only the optical interface of the PMT, but also the maximization of the PMT detection performances. The light collection uniformity across the detector is another advantage of the OLC system. By considering the case of JUNO, we will show OLC capabilities in terms of light collection and energy resolution.

  12. Image guidance improves localization of sonographically occult colorectal liver metastases

    Science.gov (United States)

    Leung, Universe; Simpson, Amber L.; Adams, Lauryn B.; Jarnagin, William R.; Miga, Michael I.; Kingham, T. Peter

    2015-03-01

    Assessing the therapeutic benefit of surgical navigation systems is a challenging problem in image-guided surgery. The exact clinical indications for patients that may benefit from these systems is not always clear, particularly for abdominal surgery where image-guidance systems have failed to take hold in the same way as orthopedic and neurosurgical applications. We report interim analysis of a prospective clinical trial for localizing small colorectal liver metastases using the Explorer system (Path Finder Technologies, Nashville, TN). Colorectal liver metastases are small lesions that can be difficult to identify with conventional intraoperative ultrasound due to echogeneity changes in the liver as a result of chemotherapy and other preoperative treatments. Interim analysis with eighteen patients shows that 9 of 15 (60%) of these occult lesions could be detected with image guidance. Image guidance changed intraoperative management in 3 (17%) cases. These results suggest that image guidance is a promising tool for localization of small occult liver metastases and that the indications for image-guided surgery are expanding.

  13. 'Trick', 'manipulation' and 'farce': Albert Moll's critique of occultism.

    Science.gov (United States)

    Wolffram, Heather

    2012-04-01

    In July 1925, the psychiatrist Albert Moll appeared before the district court in Berlin-Schöneberg charged with having defamed the medium Maria Vollhardt (alias Rudloff) in his 1924 book Der Spiritismus [Spiritism]. Supported by some of Berlin's most prominent occultists, the plaintiff--the medium's husband--argued that Moll's use of terms such as 'trick', 'manipulation' and 'farce' in reference to Vollhardt's phenomena had been libellous. In the three-part trial that followed, however, Moll's putative affront to the medium--of which he was eventually acquitted--was overshadowed, on the one hand, by a debate over the scientific status of parapsychology, and on the other, by the question of who--parapsychologists, occultists, psychiatrists or jurists--was entitled to claim epistemic authority over the occult. This paper will use the Rudloff-Moll trial as a means of examining Moll's critique of occultism, not only as it stood in the mid-1920s, but also as it had developed since the 1880s. It will also provide insight into the views of Germany's occultists and parapsychologists, who argued that their legitimate bid for scientific credibility was hindered by Dunkelmänner [obscurantists] such as Albert Moll.

  14. Advanced Electrocardiography Can Identify Occult Cardiomyopathy in Doberman Pinschers

    Science.gov (United States)

    Spiljak, M.; Petric, A. Domanjko; Wilberg, M.; Olsen, L. H.; Stepancic, A.; Schlegel, T. T.; Starc, V.

    2011-01-01

    Recently, multiple advanced resting electrocardiographic (A-ECG) techniques have improved the diagnostic value of short-duration ECG in detection of dilated cardiomyopathy (DCM) in humans. This study investigated whether 12-lead A-ECG recordings could accurately identify the occult phase of DCM in dogs. Short-duration (3-5 min) high-fidelity 12-lead ECG recordings were obtained from 31 privately-owned, clinically healthy Doberman Pinschers (5.4 +/- 1.7 years, 11/20 males/females). Dogs were divided into 2 groups: 1) 19 healthy dogs with normal echocardiographic M-mode measurements: left ventricular internal diameter in diastole (LVIDd . 47mm) and in systole (LVIDs . 38mm) and normal 24-hour ECG recordings (100 VPCs/24h; 1/12 dogs had only abnormal 24-hour ECG recordings (>100 VPCs/24h). ECG recordings were evaluated via custom software programs to calculate multiple parameters of high-frequency (HF) QRS ECG, heart rate variability, QT variability, waveform complexity and 3-D ECG. Student's t-tests determined 19 ECG parameters that were significantly different (P canine DCM as five selected ECG parameters can with reasonable accuracy identify occult DCM in Doberman Pinschers. Future extensive clinical studies need to clarify if 12-lead A-ECG could be useful as an additional screening test for canine DCM.

  15. Ex Luna Scientia: The Lunar Occultation Explorer (LOX)

    Science.gov (United States)

    Miller, Richard

    2017-01-01

    The Lunar Occultation Explorer (LOX) is a next-generation mission concept that provides new capabilities for time-domain astrophysics and established the Moon as a platform for nuclear astrophysics. Performance requirements are driven by Type-Ia supernova (SNeIa) science goals that seek to revel details of these profoundly radioactive objects, including their diversity. Primary science objectives include, but are not limited to, probing the fundamental thermonuclear physics processes, performing a census of progenitors and their explosion mechanisms, and evaluating the environmental conditions and intrinsic systematics of these enigmatic objects. LOX provides new capabilities for all-sky, continuous monitoring in the MeV regime (0.1-10 MeV) by leveraging the Lunar Occultation Technique (LOT). Key benefits of the LOX/LOT approach include maximizing the ratio of sensitive-to-total deployed mass, low implementation risk, and demonstrated operational simplicity that leverages extensive experience with planetary orbital geochemistry investigations; LOX also enables long-term monitoring of MeV gamma-ray sources, a critical capability for SNeIa science. Proof-of-principle efforts validated all aspects of the mission using previously deployed lunar science assets, and led to the first high-energy gamma-ray source detected at the Moon. LOX mission performance, development progress, and expectations for science investigations will be presented.

  16. Waves in the Martian Atmosphere: Results from MGS Radio Occultations

    Science.gov (United States)

    Flasar, F. M.; Hinson, D. P.; Tyler, G. L.

    1999-01-01

    Temperatures retrieved from Mars Global Surveyor radio occultations have been searched for evidence of waves. Emphasis has been on the initial series of occultations between 29 deg N and 64 deg S, obtained during the early martian southern summer, L(sub s) = 264 deg - 308 deg. The profiles exhibit an undulatory behavior that is suggestive of vertically propagating waves. wavelengths approximately 10 km are often dominant, but structure on smaller scales is evident. The undulatory structure is most pronounced between latitudes 29 deg N and 10 deg S, usually in regions of "interesting" topography, e.g., in the Tharsis region and near the edge of Syrtis Major. Several temperature profiles, particularly within 30 deg of the equator, exhibit lapse rates that locally become superadiabatic near the 0.4-mbar level or at higher altitudes. This implies that the waves are "breaking" and depositing horizontal momentum into the atmosphere. Such a deposition may play an important role in modulating the atmospheric winds, and characterizing the spatial and temporal distribution of these momentum transfers can provide important clues to understanding how the global circulation is maintained.

  17. The floating cardiac fat pad-sign of occult pneumothorax.

    Science.gov (United States)

    Kaufman, Claire; Bokhari, S A Jamal

    2016-08-01

    Pneumothoraces are a possible sequela of chest trauma with potential morbidity and mortality if not recognized and treated promptly. A portable supine chest radiograph is frequently the first radiologic study performed in the setting of trauma. While large pneumothoraces can be readily recognized on these radiographs, smaller pneumothoraces are missed in up to 15 % of trauma patients. There are many radiographic signs of occult pneumothoraces, and we are presenting a new radiographic sign of occult pneumothorax. The floating cardiac fat pad sign occurs when pleural air collects anteriorly and superiorly in the most non-dependent portion of the chest lifting the pericardial fat pad off the diaphragm. Lung markings are still seen surrounding the pericardial fat pad due to the inflated lower lobe of the lung resting dependently. Rapid and accurate identification of pneumothoraces is critical but often difficult on chest radiographs. Although there are many existing radiographic signs for identification of pneumothorax, prospective identification of small pneumothoraces is still relatively poor. Here, we describe an additional sign which aides in the detection of pneumothoraces, the floating cardiac fat pad. When present, this should prompt further evaluation with chest CT or upright chest radiograph.

  18. Metric regularity and subdifferential calculus

    International Nuclear Information System (INIS)

    Ioffe, A D

    2000-01-01

    The theory of metric regularity is an extension of two classical results: the Lyusternik tangent space theorem and the Graves surjection theorem. Developments in non-smooth analysis in the 1980s and 1990s paved the way for a number of far-reaching extensions of these results. It was also well understood that the phenomena behind the results are of metric origin, not connected with any linear structure. At the same time it became clear that some basic hypotheses of the subdifferential calculus are closely connected with the metric regularity of certain set-valued maps. The survey is devoted to the metric theory of metric regularity and its connection with subdifferential calculus in Banach spaces

  19. Manifold Regularized Correlation Object Tracking.

    Science.gov (United States)

    Hu, Hongwei; Ma, Bo; Shen, Jianbing; Shao, Ling

    2018-05-01

    In this paper, we propose a manifold regularized correlation tracking method with augmented samples. To make better use of the unlabeled data and the manifold structure of the sample space, a manifold regularization-based correlation filter is introduced, which aims to assign similar labels to neighbor samples. Meanwhile, the regression model is learned by exploiting the block-circulant structure of matrices resulting from the augmented translated samples over multiple base samples cropped from both target and nontarget regions. Thus, the final classifier in our method is trained with positive, negative, and unlabeled base samples, which is a semisupervised learning framework. A block optimization strategy is further introduced to learn a manifold regularization-based correlation filter for efficient online tracking. Experiments on two public tracking data sets demonstrate the superior performance of our tracker compared with the state-of-the-art tracking approaches.

  20. Dimensional regularization in configuration space

    International Nuclear Information System (INIS)

    Bollini, C.G.; Giambiagi, J.J.

    1995-09-01

    Dimensional regularization is introduced in configuration space by Fourier transforming in D-dimensions the perturbative momentum space Green functions. For this transformation, Bochner theorem is used, no extra parameters, such as those of Feynman or Bogoliubov-Shirkov are needed for convolutions. The regularized causal functions in x-space have ν-dependent moderated singularities at the origin. They can be multiplied together and Fourier transformed (Bochner) without divergence problems. The usual ultraviolet divergences appear as poles of the resultant functions of ν. Several example are discussed. (author). 9 refs

  1. Regular algebra and finite machines

    CERN Document Server

    Conway, John Horton

    2012-01-01

    World-famous mathematician John H. Conway based this classic text on a 1966 course he taught at Cambridge University. Geared toward graduate students of mathematics, it will also prove a valuable guide to researchers and professional mathematicians.His topics cover Moore's theory of experiments, Kleene's theory of regular events and expressions, Kleene algebras, the differential calculus of events, factors and the factor matrix, and the theory of operators. Additional subjects include event classes and operator classes, some regulator algebras, context-free languages, communicative regular alg

  2. Matrix regularization of 4-manifolds

    OpenAIRE

    Trzetrzelewski, M.

    2012-01-01

    We consider products of two 2-manifolds such as S^2 x S^2, embedded in Euclidean space and show that the corresponding 4-volume preserving diffeomorphism algebra can be approximated by a tensor product SU(N)xSU(N) i.e. functions on a manifold are approximated by the Kronecker product of two SU(N) matrices. A regularization of the 4-sphere is also performed by constructing N^2 x N^2 matrix representations of the 4-algebra (and as a byproduct of the 3-algebra which makes the regularization of S...

  3. Solar wind modulation of the Martian ionosphere observed by Mars Global Surveyor

    Directory of Open Access Journals (Sweden)

    J.-S. Wang

    2004-06-01

    Full Text Available Electron density profiles in the Martian ionosphere observed by the radio occultation experiment on board Mars Global Surveyor have been analyzed to determine if the densities are influenced by the solar wind. Evidence is presented that the altitude of the maximum ionospheric electron density shows a positive correlation to the energetic proton flux in the solar wind. The solar wind modulation of the Martian ionosphere can be attributed to heating of the neutral atmosphere by the solar wind energetic proton precipitation. The modulation is observed to be most prominent at high solar zenith angles. It is argued that this is consistent with the proposed modulation mechanism.

  4. Regularization of Nonmonotone Variational Inequalities

    International Nuclear Information System (INIS)

    Konnov, Igor V.; Ali, M.S.S.; Mazurkevich, E.O.

    2006-01-01

    In this paper we extend the Tikhonov-Browder regularization scheme from monotone to rather a general class of nonmonotone multivalued variational inequalities. We show that their convergence conditions hold for some classes of perfectly and nonperfectly competitive economic equilibrium problems

  5. Lattice regularized chiral perturbation theory

    International Nuclear Information System (INIS)

    Borasoy, Bugra; Lewis, Randy; Ouimet, Pierre-Philippe A.

    2004-01-01

    Chiral perturbation theory can be defined and regularized on a spacetime lattice. A few motivations are discussed here, and an explicit lattice Lagrangian is reviewed. A particular aspect of the connection between lattice chiral perturbation theory and lattice QCD is explored through a study of the Wess-Zumino-Witten term

  6. 76 FR 3629 - Regular Meeting

    Science.gov (United States)

    2011-01-20

    ... Meeting SUMMARY: Notice is hereby given of the regular meeting of the Farm Credit System Insurance Corporation Board (Board). Date and Time: The meeting of the Board will be held at the offices of the Farm... meeting of the Board will be open to the [[Page 3630

  7. Forcing absoluteness and regularity properties

    NARCIS (Netherlands)

    Ikegami, D.

    2010-01-01

    For a large natural class of forcing notions, we prove general equivalence theorems between forcing absoluteness statements, regularity properties, and transcendence properties over L and the core model K. We use our results to answer open questions from set theory of the reals.

  8. Globals of Completely Regular Monoids

    Institute of Scientific and Technical Information of China (English)

    Wu Qian-qian; Gan Ai-ping; Du Xian-kun

    2015-01-01

    An element of a semigroup S is called irreducible if it cannot be expressed as a product of two elements in S both distinct from itself. In this paper we show that the class C of all completely regular monoids with irreducible identity elements satisfies the strong isomorphism property and so it is globally determined.

  9. Fluid queues and regular variation

    NARCIS (Netherlands)

    Boxma, O.J.

    1996-01-01

    This paper considers a fluid queueing system, fed by N independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index ¿. We show that its fat tail gives rise to an even

  10. Fluid queues and regular variation

    NARCIS (Netherlands)

    O.J. Boxma (Onno)

    1996-01-01

    textabstractThis paper considers a fluid queueing system, fed by $N$ independent sources that alternate between silence and activity periods. We assume that the distribution of the activity periods of one or more sources is a regularly varying function of index $zeta$. We show that its fat tail

  11. Empirical laws, regularity and necessity

    NARCIS (Netherlands)

    Koningsveld, H.

    1973-01-01

    In this book I have tried to develop an analysis of the concept of an empirical law, an analysis that differs in many ways from the alternative analyse's found in contemporary literature dealing with the subject.

    1 am referring especially to two well-known views, viz. the regularity and

  12. Interval matrices: Regularity generates singularity

    Czech Academy of Sciences Publication Activity Database

    Rohn, Jiří; Shary, S.P.

    2018-01-01

    Roč. 540, 1 March (2018), s. 149-159 ISSN 0024-3795 Institutional support: RVO:67985807 Keywords : interval matrix * regularity * singularity * P-matrix * absolute value equation * diagonally singilarizable matrix Subject RIV: BA - General Mathematics Impact factor: 0.973, year: 2016

  13. Regularization in Matrix Relevance Learning

    NARCIS (Netherlands)

    Schneider, Petra; Bunte, Kerstin; Stiekema, Han; Hammer, Barbara; Villmann, Thomas; Biehl, Michael

    A In this paper, we present a regularization technique to extend recently proposed matrix learning schemes in learning vector quantization (LVQ). These learning algorithms extend the concept of adaptive distance measures in LVQ to the use of relevance matrices. In general, metric learning can

  14. Diffraction-based analysis of tunnel size for a scaled external occulter testbed

    Science.gov (United States)

    Sirbu, Dan; Kasdin, N. Jeremy; Vanderbei, Robert J.

    2016-07-01

    For performance verification of an external occulter mask (also called a starshade), scaled testbeds have been developed to measure the suppression of the occulter shadow in the pupil plane and contrast in the image plane. For occulter experiments the scaling is typically performed by maintaining an equivalent Fresnel number. The original Princeton occulter testbed was oversized with respect to both input beam and shadow propagation to limit any diffraction effects due to finite testbed enclosure edges; however, to operate at realistic space-mission equivalent Fresnel numbers an extended testbed is currently under construction. With the longer propagation distances involved, diffraction effects due to the edge of the tunnel must now be considered in the experiment design. Here, we present a diffraction-based model of two separate tunnel effects. First, we consider the effect of tunnel-edge induced diffraction ringing upstream from the occulter mask. Second, we consider the diffraction effect due to clipping of the output shadow by the tunnel downstream from the occulter mask. These calculations are performed for a representative point design relevant to the new Princeton occulter experiment, but we also present an analytical relation that can be used for other propagation distances.

  15. Occult HBV infection in HIV-infected adults and evaluation of pooled NAT for HBV.

    Science.gov (United States)

    Dinesha, T R; Boobalan, J; Sivamalar, S; Subashini, D; Solomon, S S; Murugavel, K G; Balakrishnan, P; Smith, D M; Saravanan, S

    2018-01-06

    The study aimed to determine the prevalence of occult hepatitis B virus infection among HIV-infected persons and to evaluate the use of a pooling strategy to detect occult HBV infection in the setting of HIV infection. Five hundred and two HIV-positive individuals were tested for HBV, occult HBV and hepatitis C and D with serologic and nucleic acid testing (NAT). We also evaluated a pooled NAT strategy for screening occult HBV infection among the HIV-positive individuals. The prevalence of HBV infection among HIV-positive individuals was 32 (6.4%), and occult HBV prevalence was 10%. The pooling HBV NAT had a sensitivity of 66.7% and specificity of 100%, compared to HBV DNA NAT of individual samples. In conclusion, this study found a high prevalence of occult HBV infection among our HIV-infected population. We also demonstrated that pooled HBV NAT is highly specific, moderately sensitive and cost-effective. As conventional HBV viral load assays are expensive in resource-limited settings such as India, pooled HBV DNA NAT might be a good way for detecting occult HBV infection and will reduce HBV-associated complications. © 2018 John Wiley & Sons Ltd.

  16. Noninvasive Prenatal Testing and Incidental Detection of Occult Maternal Malignancies.

    Science.gov (United States)

    Bianchi, Diana W; Chudova, Darya; Sehnert, Amy J; Bhatt, Sucheta; Murray, Kathryn; Prosen, Tracy L; Garber, Judy E; Wilkins-Haug, Louise; Vora, Neeta L; Warsof, Stephen; Goldberg, James; Ziainia, Tina; Halks-Miller, Meredith

    2015-07-14

    Understanding the relationship between aneuploidy detection on noninvasive prenatal testing (NIPT) and occult maternal malignancies may explain results that are discordant with the fetal karyotype and improve maternal clinical care. To evaluate massively parallel sequencing data for patterns of copy-number variations that might prospectively identify occult maternal malignancies. Case series identified from 125,426 samples submitted between February 15, 2012, and September 30, 2014, from asymptomatic pregnant women who underwent plasma cell-free DNA sequencing for clinical prenatal aneuploidy screening. Analyses were conducted in a clinical laboratory that performs DNA sequencing. Among the clinical samples, abnormal results were detected in 3757 (3%); these were reported to the ordering physician with recommendations for further evaluation. NIPT for fetal aneuploidy screening (chromosomes 13, 18, 21, X, and Y). Detailed genome-wide bioinformatics analysis was performed on available sequencing data from 8 of 10 women with known cancers. Genome-wide copy-number changes in the original NIPT samples and in subsequent serial samples from individual patients when available are reported. Copy-number changes detected in NIPT sequencing data in the known cancer cases were compared with the types of aneuploidies detected in the overall cohort. From a cohort of 125,426 NIPT results, 3757 (3%) were positive for 1 or more aneuploidies involving chromosomes 13, 18, 21, X, or Y. From this set of 3757 samples, 10 cases of maternal cancer were identified. Detailed clinical and sequencing data were obtained in 8. Maternal cancers most frequently occurred with the rare NIPT finding of more than 1 aneuploidy detected (7 known cancers among 39 cases of multiple aneuploidies by NIPT, 18% [95% CI, 7.5%-33.5%]). All 8 cases that underwent further bioinformatics analysis showed unique patterns of nonspecific copy-number gains and losses across multiple chromosomes. In 1 case, blood was

  17. Regular and conformal regular cores for static and rotating solutions

    Energy Technology Data Exchange (ETDEWEB)

    Azreg-Aïnou, Mustapha

    2014-03-07

    Using a new metric for generating rotating solutions, we derive in a general fashion the solution of an imperfect fluid and that of its conformal homolog. We discuss the conditions that the stress–energy tensors and invariant scalars be regular. On classical physical grounds, it is stressed that conformal fluids used as cores for static or rotating solutions are exempt from any malicious behavior in that they are finite and defined everywhere.

  18. Regular and conformal regular cores for static and rotating solutions

    International Nuclear Information System (INIS)

    Azreg-Aïnou, Mustapha

    2014-01-01

    Using a new metric for generating rotating solutions, we derive in a general fashion the solution of an imperfect fluid and that of its conformal homolog. We discuss the conditions that the stress–energy tensors and invariant scalars be regular. On classical physical grounds, it is stressed that conformal fluids used as cores for static or rotating solutions are exempt from any malicious behavior in that they are finite and defined everywhere.

  19. First light of an external occulter testbed at flight Fresnel numbers

    Science.gov (United States)

    Kim, Yunjong; Sirbu, Dan; Hu, Mia; Kasdin, Jeremy; Vanderbei, Robert J.; Harness, Anthony; Shaklan, Stuart

    2017-01-01

    Many approaches have been suggested over the last couple of decades for imaging Earth-like planets. One of the main candidates for creating high-contrast for future Earth-like planets detection is an external occulter. The external occulter is a spacecraft flown along the line-of-sight of a space telescope to suppress starlight and enable high-contrast direct imaging of exoplanets. The occulter is typically tens of meters in diameter and the separation from the telescope is of the order of tens of thousands of kilometers. Optical testing of a full-scale external occulter on the ground is impossible because of the long separations. Therefore, laboratory verification of occulter designs is necessary to validate the optical models used to design and predict occulter performance. At Princeton, we have designed and built a testbed that allows verification of scaled occulter designs whose suppressed shadow is mathematically identical to that of space occulters. The goal of this experiment is to demonstrate a pupil plane suppression of better than 1e-9 with a corresponding image plane contrast of better than 1e-11. The occulter testbed uses a 77.2 m optical propagation distance to realize the flight Fresnel number of 14.5. The scaled mask is placed at 27.2 m from the artificial source and the camera is located 50.0 m from the scaled mask. We will use an etched silicon mask, manufactured by the Microdevices Lab(MDL) of the Jet Propulsion Laboratory(JPL), as the occulter. Based on conversations with MDL, we expect that 0.5 μm feature size is an achievable resolution in the mask manufacturing process and is therefore likely the indicator of the best possible performance. The occulter is illuminated by a diverging laser beam to reduce the aberrations from the optics before the occulter. Here, we present first light result of a sample design operating at a flight Fresnel number and the experimental setup of the testbed. We compare the experimental results with simulations

  20. Heparin as a pharmacologic intervention to induce positive scintiscan in occult gastrointestinal bleeding

    International Nuclear Information System (INIS)

    Chaudhuri, T.K.; Brantly, M.

    1984-01-01

    The value of using heparin as a pharmacologic intervention to induce a positive scintiscan was studied in a patient with chronic occult gastrointestinal bleeding. When all standard diagnostic tests (upper and lower gastrointestinal series, upper and lower endoscopy, and conventional noninterventional Tc-99m RBC imaging) fail to detect and localize gastrointestinal bleeding in a patient who has definite clinical evidence (guaiac positive stool and dropping hemoglobin, hematocrit) of chronic occult gastrointestinal oozing, heparin may be used (with proper precaution) as a last resort to aid in the scintigraphic detection and localization of chronic occult gastrointestinal bleeding

  1. Acute Zonal Occult Outer Retinopathy with Atypical Findings

    Directory of Open Access Journals (Sweden)

    Dimitrios Karagiannis

    2014-01-01

    Full Text Available Background. To report a case of acute zonal occult outer retinopathy (AZOOR with atypical electrophysiology findings. Case Presentation. A 23-year-old-female presented with visual acuity deterioration in her right eye accompanied by photopsia bilaterally. Corrected distance visual acuity at presentation was 20/50 in the right eye and 20/20 in the left eye. Fundus examination was unremarkable. Visual field (VF testing revealed a large scotoma. Pattern and full-field electroretinograms (PERG and ERG revealed macular involvement associated with generalized retinal dysfunction. Electrooculogram (EOG light rise and the Arden ratio were within normal limits bilaterally. The patient was diagnosed with AZOOR due to clinical findings, visual field defect, and ERG findings. Conclusion. This is a case of AZOOR with characteristic VF defects and clinical symptoms presenting with atypical EOG findings.

  2. Radiosensitive orbital metastasis as presentation of occult colonic adenocarcinoma.

    Science.gov (United States)

    Ludmir, Ethan B; McCall, Shannon J; Czito, Brian G; Palta, Manisha

    2014-09-19

    An 82-year-old man presented with progressive right frontal headaches. The patient's history was significant for benign polyps on surveillance colonoscopy 2 years prior, without high-grade dysplasia or carcinoma. MRI revealed an enhancing lesion arising within the superomedial aspect of the right orbit. Lesion biopsy demonstrated histological appearance and immunophenotype suggestive of colonic adenocarcinoma. Staging positron emission tomography/CT showed visceral metastases and diffuse activity in the posterior rectosigmoid, consistent with metastatic colon cancer. Treatment of the orbital lesion with external beam radiotherapy to 30 Gy resulted in significant palliation of the patient's headaches. The patient expired 2 months following treatment completion due to disease progression. Orbital metastasis as the initial presentation of an occult colorectal primary lesion is exceedingly rare, and occurred in this patient despite surveillance colonoscopy. Radiotherapy remains an efficacious modality for treatment of orbital metastases. 2014 BMJ Publishing Group Ltd.

  3. Lunar occultations for gamma-ray source measurements

    Science.gov (United States)

    Koch, David G.; Hughes, E. B.; Nolan, Patrick L.

    1990-01-01

    The unambiguous association of discrete gamma-ray sources with objects radiating at other wavelengths, the separation of discrete sources from the extended emission within the Galaxy, the mapping of gamma-ray emission from nearby galaxies and the measurement of structure within a discrete source cannot presently be accomplished at gamma-ray energies. In the past, the detection processes used in high-energy gamma-ray astronomy have not allowed for good angular resolution. This problem can be overcome by placing gamma-ray detectors on the moon and using the horizon as an occulting edge to achieve arcsec resolution. For purposes of discussion, this concept is examined for gamma rays above 100 MeV for which pair production dominates the detection process and locally-generated nuclear gamma rays do not contribute to the background.

  4. Management of occult stress urinary incontinence with prolapse surgery.

    Science.gov (United States)

    Al-Mandeel, H; Al-Badr, A

    2013-08-01

    Pelvic organ prolapse (POP) and stress urinary incontinence (SUI), are two common health-related conditions, each affecting up to 50% women worldwide. Stress urinary incontinence only observed after the reduction of co-existent prolapse is called occult SUI (OSUI), and is found in up to 80% of women with advanced POP. Although there is no consensus on how to diagnose OSUI, there are several reported methods to better diagnose. Counseling symptomatically continent women with POP concerning the potential risk for developing SUI postoperatively cannot be overstated. Evidence suggests that positive OSUI in symptomatically continent women who are planning to have POP repair is associated with a high risk of POSUI, furthermore, adding continence procedure is found to reduce postoperative SUI. Therefore, adding continence surgery at the time of POP surgery in patients who are found to have OSUI preoperatively is advocated.

  5. Adolescent Occultism and the Philosophy of Things in Three Novels

    Directory of Open Access Journals (Sweden)

    Samuel Finegan

    2015-11-01

    Full Text Available Shirley Jackson’s 1962 We Have Always Lived in the Castle, Iain Banks’s 1984 The Wasp Factory and Sonya Hartnett’s 2009 Butterfly are novels separated not only by decades, but by distance being produced in the United States, Scotland and Australia respectively. Despite this, each of these texts depicts a young adult in a mimetically recognisable world struggling to reconcile their intuitive occultism with that world. The mediation of magic through assemblages of charged objects creates a philosophy of things – modelling in intuitive and narrative terms the essence and nature of objects familiar from the philosophies of Martin Heidegger and Walter Benjamin. As such, the supernaturalism of Iain Banks, Shirley Jackson and Sonya Hartnett’s narratives implicates their readers – breaking the boundaries of fiction to comment on the material world itself, not through analogy or metaphor but through direct modelling of the potential power and worth of things.

  6. Radiographically Occult and Subtle Fractures: A Pictorial Review

    International Nuclear Information System (INIS)

    Jarraya, M.; Hayashi, D.; Roemer, F.W.; Crema, M.D.; Conlin, J.; Marra, M.D.; Guermazi, A.; Roemer, F.W.; Crema, M.D.; Diaz, L.; Conlin, J.; Jomaah, N.

    2013-01-01

    Radiographically occult and subtle fractures are a diagnostic challenge. They may be divided into (1) high energy trauma fracture, (2) fatigue fracture from cyclical and sustained mechanical stress, and (3) insufficiency fracture occurring in weakened bone (e.g., in osteoporosis and post radiotherapy). Independently of the cause, the initial radiographic examination can be negative either because the findings seem normal or are too subtle. Early detection of these fractures is crucial to explain the patients symptoms and prevent further complications. Advanced imaging tools such as computed tomography, magnetic resonance imaging, and scintigraphy are highly valuable in this context. Our aim is to raise the awareness of radiologists and clinicians in these cases by presenting illustrative cases and a discussion of the relevant literature.

  7. Solar Indices - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  8. Solar Indices - Solar Ultraviolet

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  9. Solar Indices - Solar Corona

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  10. Solar Indices - Solar Irradiance

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  11. Small Spacecraft Constellation Concept for Mars Atmospheric Radio Occultations

    Science.gov (United States)

    Asmar, S. W.; Mannucci, A. J.; Ao, C. O.; Kobayashi, M. M.; Lazio, J.; Marinan, A.; Massone, G.; McCandless, S. E.; Preston, R. A.; Seubert, J.; Williamson, W.

    2017-12-01

    First demonstrated in 1965 when Mariner IV flew by Mars and determined the salient features of its atmosphere, radio occultation experiments have been carried out on numerous planetary missions with great discoveries. These experiments utilize the now classic configuration of a signal from a single planetary spacecraft to Earth receiving stations, where the science data are acquired. The Earth science community advanced the technique to utilizing a constellation of spacecraft with the radio occultation links between the spacecraft, enabled by the infrastructure of the Global Positioning System. With the advent of small and less costly spacecraft, such as planetary CubeSats and other variations, such as the anticipated innovative Mars Cube One mission, crosslinks among small spacecraft can be used to study other planets in the near future. Advantages of this type of experiment include significantly greater geographical coverage, which could reach global coverage over a few weeks with a small number of spacecraft. Repeatability of the global coverage can lead to examining temperature-pressure profiles and ionospheric electron density profiles, on daily, seasonal, annual, or other time scales of interest. The higher signal-to-noise ratio for inter-satellite links, compared to a link to Earth, decreases the design demands on the instrumentation (smaller antennas and transmitters, etc.). After an actual Mars crosslink demonstration, this concept has been in development using Mars as a possible target. Scientific objectives, delivery methods, operational scenarios and end-to-end configuration have been documented. Science objectives include determining the state and variability of the lower Martian atmosphere, which has been an identified as a high priority objective by the Mars Exploration Program Analysis Group, particularly as it relates to entry, descent, and landing and ascent for future crewed and robotic missions. This paper will present the latest research on the

  12. The prototype cameras for trans-Neptunian automatic occultation survey

    Science.gov (United States)

    Wang, Shiang-Yu; Ling, Hung-Hsu; Hu, Yen-Sang; Geary, John C.; Chang, Yin-Chang; Chen, Hsin-Yo; Amato, Stephen M.; Huang, Pin-Jie; Pratlong, Jerome; Szentgyorgyi, Andrew; Lehner, Matthew; Norton, Timothy; Jorden, Paul

    2016-08-01

    The Transneptunian Automated Occultation Survey (TAOS II) is a three robotic telescope project to detect the stellar occultation events generated by TransNeptunian Objects (TNOs). TAOS II project aims to monitor about 10000 stars simultaneously at 20Hz to enable statistically significant event rate. The TAOS II camera is designed to cover the 1.7 degrees diameter field of view of the 1.3m telescope with 10 mosaic 4.5k×2k CMOS sensors. The new CMOS sensor (CIS 113) has a back illumination thinned structure and high sensitivity to provide similar performance to that of the back-illumination thinned CCDs. Due to the requirements of high performance and high speed, the development of the new CMOS sensor is still in progress. Before the science arrays are delivered, a prototype camera is developed to help on the commissioning of the robotic telescope system. The prototype camera uses the small format e2v CIS 107 device but with the same dewar and also the similar control electronics as the TAOS II science camera. The sensors, mounted on a single Invar plate, are cooled to the operation temperature of about 200K as the science array by a cryogenic cooler. The Invar plate is connected to the dewar body through a supporting ring with three G10 bipods. The control electronics consists of analog part and a Xilinx FPGA based digital circuit. One FPGA is needed to control and process the signal from a CMOS sensor for 20Hz region of interests (ROI) readout.

  13. Between occultism and drama. Henrik Ibsen and Aleister Crowley

    Directory of Open Access Journals (Sweden)

    Giuliano D' Amico

    2015-02-01

    Full Text Available The article investigates the references to the works of Henrik Ibsen that the writer and occultist Aleister Crowley scattered in his writings around the turn of the 20th century, in the early phase of his career as a writer and occultist. Crowley’s reading of Ibsen has a marked a socio-political bent, especially in his interpretation of the work of the Norwegian playwright as an act of rebellion against the bourgeois (and for Crowley, Victorian system of values. Also, such view is enriched by a spiritual and individualistic interpretation of Ibsen as an “Artist”, i.e., in the light of Crowley’s occult doctrine, Thelema, of an individual who has found his own “Will” and can inspire others to do so. Such social and spiritual interpretations of Ibsen on Crowley’s part found their literary realization in his one-act play The Mother’s Tragedy (1899. The article claims that Crowley’s reading of Ibsen can give some new insight in the mechanisms of reception of the Norwegian playwright, by opening up for a reading of some of his plays within an occult discourse. Also, it is an occasion to treat Crowley – a figure that was constantly present in the European cultural and literary life of the last decade of the 19th century and of the first five decades of the 20th – with a different attitude than the irony and disdain to which he is often exposed.

  14. Mapping Pluto's Temperature Distribution Through Twenty Years of Stellar Occultations

    Science.gov (United States)

    Zangari, Amanda; Binzel, R. P.; Person, M. J.

    2012-10-01

    Multi-chord, high signal-to-noise Pluto occultations have been observed several times over the past two decades, including events in 1988, 2002, 2006, 2007, 2010 and 2011 (Elliot et al. 1989, 2003, 2007; Person et al. 2008, 2010, 2011). We fit separate immersion and emersion occultation light-curve models to each of the individual light curves obtained from these efforts. Asymmetries in the light curves result in the half-light temperatures for opposite sides of a single chord to differ by up to 20 Kelvin in the largest case. The temperature difference for each chord is consistent using both isothermal (b=0) and non-isothermal (e.g. b=-2.2) models based on the methodology described by Elliot & Young (1992). We examine the relationship between the location of immersion and emersion points on Pluto and these temperatures at the half-light radius and will present results for correlations between these location/temperature data and surface composition maps, Pluto geometry, and accumulated insolation patterns. This work was supported by NASA Planetary Astronomy Grant to MIT (NNX10AB27G), and NSF Astronomy and Astrophysics Grant to MIT (0707609). The authors would like to acknowledge the late Professor James L. Elliot for his efforts in beginning this work. References: Elliot, J. L., Dunham, E. W., Bosh, A. S., et al. 1989, Icarus, 77,148 Elliot, J. L., Ates, A., Babcock, B. A., et al. 2003, Nature, 424,165 Elliot, J. L., Person, M. J., Gulbis, A. A. S., et al. 2007, AJ, 134, 1 Elliot, J. L., & Young, L. A. 1992, AJ, 103, 991. Person, M. J., Elliot, J. L., Gulbis, A. A. S., et al. 2008, AJ, 136, 1510 Person, M. J., Elliot, J. L., Bosh, A. S., et al. 2010, Bulletin of the American Astronomical Society, 42, 983 Person, M. J., Dunham, E. W., Bida, T., et al. 2011, EPSC-DPS Joint Meeting 2011, 1374.

  15. Magellan radio occultation measurements of atmospheric waves on Venus

    Science.gov (United States)

    Hinson, David P.; Jenkins, J. M.

    1995-01-01

    Radio occultation experiments were conducted at Venus on three consecutive orbits of the Magellan spacecraft in October 1991. Each occultation occurred over the same topography (67 deg N, 127 deg E) and at the same local time (22 hr 5 min), but the data are sensitive to zonal variations because the atmosphere rotates significantly during one orbit. Through comparisons between observations and predictions of standard wave theory, we have demonstrated that small-scale oscillations in retrieved temperature profiles as well as scintillations in received signal intensity are caused by a spectrum of vertically propagating internal gravity waves. There is a strong similarity between the intensity scintillations observed here and previous measurements, which pertain to a wide range of locations and experiment dates. This implies that the same basic phenomenon underlies all the observations and hence that gravity waves are a persistent, global feature of Venus' atmosphere. We obtained a fairly complete characterization of a gravity wave that appears above the middle cloud in temperature measurements on all three orbits. The amplitude and vertical wavelength are about 4 K and 2.5 km respectively, at 65 km. A model for radiative damping implies that the wave intrinsic frequency is approximately 2 x 10(exp 4) rad/sec, the corresponding ratio between horizontal and vertical wavelengths is approximately 100. The wave is nearly stationary relative to the surface or the Sun. Radiative attenuation limits the wave amplitude at altitudes above approximately 65 km, leading to wave drag on the mean zonal winds of about +0.4 m/sec per day (eastward). The sign, magnitude, and location of this forcing suggest a possible role in explaining the decrease with height in the zonal wind speed that is believed to occur above the cloud tops. Temperature oscillations with larger vertical wavelengths (5-10 km) were also observed on all three orbits, but we are able unable to interpret these

  16. Energy functions for regularization algorithms

    Science.gov (United States)

    Delingette, H.; Hebert, M.; Ikeuchi, K.

    1991-01-01

    Regularization techniques are widely used for inverse problem solving in computer vision such as surface reconstruction, edge detection, or optical flow estimation. Energy functions used for regularization algorithms measure how smooth a curve or surface is, and to render acceptable solutions these energies must verify certain properties such as invariance with Euclidean transformations or invariance with parameterization. The notion of smoothness energy is extended here to the notion of a differential stabilizer, and it is shown that to void the systematic underestimation of undercurvature for planar curve fitting, it is necessary that circles be the curves of maximum smoothness. A set of stabilizers is proposed that meet this condition as well as invariance with rotation and parameterization.

  17. Physical model of dimensional regularization

    Energy Technology Data Exchange (ETDEWEB)

    Schonfeld, Jonathan F.

    2016-12-15

    We explicitly construct fractals of dimension 4-ε on which dimensional regularization approximates scalar-field-only quantum-field theory amplitudes. The construction does not require fractals to be Lorentz-invariant in any sense, and we argue that there probably is no Lorentz-invariant fractal of dimension greater than 2. We derive dimensional regularization's power-law screening first for fractals obtained by removing voids from 3-dimensional Euclidean space. The derivation applies techniques from elementary dielectric theory. Surprisingly, fractal geometry by itself does not guarantee the appropriate power-law behavior; boundary conditions at fractal voids also play an important role. We then extend the derivation to 4-dimensional Minkowski space. We comment on generalization to non-scalar fields, and speculate about implications for quantum gravity. (orig.)

  18. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan

    2014-09-07

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  19. Maximum mutual information regularized classification

    KAUST Repository

    Wang, Jim Jing-Yan; Wang, Yi; Zhao, Shiguang; Gao, Xin

    2014-01-01

    In this paper, a novel pattern classification approach is proposed by regularizing the classifier learning to maximize mutual information between the classification response and the true class label. We argue that, with the learned classifier, the uncertainty of the true class label of a data sample should be reduced by knowing its classification response as much as possible. The reduced uncertainty is measured by the mutual information between the classification response and the true class label. To this end, when learning a linear classifier, we propose to maximize the mutual information between classification responses and true class labels of training samples, besides minimizing the classification error and reducing the classifier complexity. An objective function is constructed by modeling mutual information with entropy estimation, and it is optimized by a gradient descend method in an iterative algorithm. Experiments on two real world pattern classification problems show the significant improvements achieved by maximum mutual information regularization.

  20. Regularized strings with extrinsic curvature

    International Nuclear Information System (INIS)

    Ambjoern, J.; Durhuus, B.

    1987-07-01

    We analyze models of discretized string theories, where the path integral over world sheet variables is regularized by summing over triangulated surfaces. The inclusion of curvature in the action is a necessity for the scaling of the string tension. We discuss the physical properties of models with extrinsic curvature terms in the action and show that the string tension vanishes at the critical point where the bare extrinsic curvature coupling tends to infinity. Similar results are derived for models with intrinsic curvature. (orig.)

  1. Circuit complexity of regular languages

    Czech Academy of Sciences Publication Activity Database

    Koucký, Michal

    2009-01-01

    Roč. 45, č. 4 (2009), s. 865-879 ISSN 1432-4350 R&D Projects: GA ČR GP201/07/P276; GA MŠk(CZ) 1M0545 Institutional research plan: CEZ:AV0Z10190503 Keywords : regular languages * circuit complexity * upper and lower bounds Subject RIV: BA - General Mathematics Impact factor: 0.726, year: 2009

  2. Long-term comparison of the ionospheric F2 layer electron density peak derived from ionosonde data and Formosat-3/COSMIC occultations

    Directory of Open Access Journals (Sweden)

    Limberger Marco

    2015-01-01

    Full Text Available Electron density profiles (EDPs derived from GNSS radio occultation (RO measurements provide valuable information on the vertical electron density structure of the ionosphere and, among others, allow the extraction of key parameters such as the maximum electron density NmF2 and the corresponding peak height hmF2 of the F2 layer. An efficient electron density retrieval method, developed at the UPC (Barcelona, Spain, has been applied in this work to assess the accuracy of NmF2and hmF2 as determined from Formosat-3/COSMIC (F-3/C radio occultation measurements for a period of more than half a solar cycle between 2006 and 2014. Ionosonde measurements of the Space Physics Interactive Data Resource (SPIDR network serve as a reference. Investigations on the global trend as well as comparisons of the F2 layer electron density peaks derived from both occultations and ionosonde measurements are carried out. The studies are performed in the global domain and with the distinction of different latitude sectors around the magnetic equator ±[0°, 20°], ±]20°, 60°] and ±]60°, 90°] and local times (LT accounting for different ionospheric conditions at night (02:00 LT ± 2 h, dawn (08:00 LT ± 2 h, and day (14:00 LT ± 2 h. The mean differences of F2 layer electron density peaks observed by F-3/C and ionosondes are found to be insignificant. Relative variations of the peak differences are determined in the range of 22%–30% for NmF2 and 10%–15% for hmF2. The consistency of observations is generally high for the equatorial and mid-latitude sectors at daytime and dawn whereas degradations have been detected in the polar regions and during night. It is shown, that the global averages of NmF2 and hmF2 derived from F-3/C occultations appear as excellent indicators for the solar activity.

  3. General inverse problems for regular variation

    DEFF Research Database (Denmark)

    Damek, Ewa; Mikosch, Thomas Valentin; Rosinski, Jan

    2014-01-01

    Regular variation of distributional tails is known to be preserved by various linear transformations of some random structures. An inverse problem for regular variation aims at understanding whether the regular variation of a transformed random object is caused by regular variation of components ...

  4. Harmonic analysis of the ionospheric electron densities retrieved from FORMOSAT-3/COSMIC radio occultation measurements

    Science.gov (United States)

    Masoumi, S.; Safari, A.; Sharifi, M.; Sam Khaniani, A.

    2011-12-01

    In order to investigate regular variations of the ionosphere, the least-squares harmonic estimation is applied to the time series of ionospheric electron densities in the region of Iran derived from about five years of Global Positioning System Radio Occultation (GPS RO) observations by FORMOSAT-3/COSMIC satellites. Although the obtained results are slightly different from the expected ones due to the low horizontal resolution of RO measurements, high vertical resolution of the observations enables us to detect not only the Total Electron Content (TEC) variations, but also periodic patterns of electron densities in different altitudes of the ionosphere. Dominant diurnal and annual signals, together with their Fourier series decompositions, and also periods close to 27 days are obtained, which is consistent with the previous analyses on TEC. In the equatorial anomaly band, the annual component is weaker than its Fourier decomposition periods. In particular, the semiannual period dominates the annual component, which is probably due to the effect of geomagnetic field. By the investigation of the frequencies at different local times, the semiannual signal is more significant than the annual one in the daytime, while the annual frequency is dominant at night. By the detection of the phases of the components, it is revealed that the annual signal has its maximum in summer at high altitudes, and in winter at lower altitudes. This suggests the effect of neutral compositions in the lower atmosphere. Further, the semiannual component peaks around equinox during the day, while its maximum mostly occurs in solstice at night. Since RO measurements can be used to derive TEC along the signal path between a GPS satellite and a receiver, study on the potentiality of using these observations for the prediction of electron densities and its application to the ionospheric correction of the single frequency receivers is suggested.

  5. Fecal Occult Blood Test (FOBT): MedlinePlus Lab Test Information

    Science.gov (United States)

    ... caused by a variety of conditions, including: Polyps Hemorrhoids Diverticulosis Ulcers Colitis , a type of inflammatory bowel ... on a fecal occult blood test include ulcers, hemorrhoids, polyps, and benign tumors. If your test results ...

  6. Observations of Hot-Jupiter occultations combining Spitzer and Kepler photometry

    Directory of Open Access Journals (Sweden)

    Knutson H.

    2011-02-01

    Full Text Available We present the status of an ongoing program which aim at measuring occultations by their parent stars of transiting hot giant exoplanets discovered recently by Kepler. The observations are obtained in the near infrared with WarmSpitzer Space Telescope and at optical wavelengths by combining more than a year of Kepler photometry. The investigation consists of measuring the mid-occultation times and the relative occultation depths in each band-passes. Our measurements of occultations depths in the Kepler bandpass is turned into the determination of the optical geometric albedo Ag in this wavelength domain. The brightness temperatures of these planets are deduced from the infrared observations. We combine the optical and near infrared planetary emergent fluxes to obtain broad band emergent spectra of individual planet. We finally compare these spectra to hot Jupiter atmospheric models in order broadly distinguishing these atmospheres between different classes of models.

  7. Parapsychology on the couch: the psychology of occult belief in Germany, c. 1870-1939.

    Science.gov (United States)

    Wolffram, Heather

    2006-01-01

    This article considers the attempts of academic psychologists and critical occultists in Germany during the late nineteenth and early twentieth centuries to construct a psychology of occult belief. While they claimed that the purpose of this new subdiscipline was to help evaluate the work of occult researchers, the emergence of a psychology of occult belief in Germany served primarily to pathologize parapsychology and its practitioners. Not to be outdone, however, parapsychologists argued that their adversaries suffered from a morbid inability to accept the reality of the paranormal. Unable to resolve through experimental means the dispute over who should be allowed to mold the public's understanding of the occult, both sides resorted to defaming their opponent. (c) 2006 Wiley Periodicals, Inc.

  8. Metastatic Squamous Neck Cancer with Occult Primary Treatment (PDQ®)—Health Professional Version

    Science.gov (United States)

    Metastatic squamous neck cancer with occult primary treatment options include surgery, radiation therapy or a combination of both. Get detailed information about newly diagnosed or recurrent metastatic squamous neck cancer in this summary for clinicians.

  9. Metastatic Squamous Neck Cancer with Occult Primary Treatment (PDQ®)—Patient Version

    Science.gov (United States)

    Metastatic squamous neck cancer with occult primary (unknown primary) treatment options include surgery, radiation therapy, or a combination of both. Learn more about the diagnosis and treatment of these tumors in this expert-reviewed summary.

  10. Prevalence of Visible and Occult Blood on the Surfaces of Fiberoptic Bronchoscopes

    National Research Council Canada - National Science Library

    McKamey, Jeffrey

    2000-01-01

    .... This study was conducted to determine if current cleaning, disinfection and sterilization procedures used at one medical center was adequate to remove visible and occult blood from fiberoptic bronchoscopes...

  11. Detection of an occult transclival cerebrospinal fluid fistula by CT and MRI

    International Nuclear Information System (INIS)

    Schick, B.; Brors, D.; Draf, W.; Goedecke, A.; Prescher, A.

    1998-01-01

    We describe an unusual occult transclival cerebrospinal fluid (CSF) fistula to the sphenoid sinus demonstrated by MRI. CT was performed because of a posterior cerebral infarct caused by cardiac arrhythmia. Axial sections showed fluid in the sphenoid sinus. High-resolution scans revealed a bony defect 3 mm in diameter of the posterior wall of the sphenoid sinus, and MRI showed a transclival CSF fistula. This occult lesion was confirmed by surgery and duraplasty was successfully performed via an endonasal approach. (orig.)

  12. Multi-thermal dynamics and energetics of a coronal mass ejection in the low solar atmosphere

    Science.gov (United States)

    Hannah, I. G.; Kontar, E. P.

    2013-05-01

    Aims: The aim of this work is to determine the multi-thermal characteristics and plasma energetics of an eruptive plasmoid and occulted flare observed by the Solar Dynamics Observatory's Atmospheric Imaging Assembly (SDO/AIA). Methods: We study a 2010 Nov. 3 event (peaking at 12:20 UT in GOES soft X-rays) of a coronal mass ejection and occulted flare that demonstrates the morphology of a classic erupting flux rope. The high spatial and time resolution and six coronal channels of the SDO/AIA images allows the dynamics of the multi-thermal emission during the initial phases of eruption to be studied in detail. The differential emission measure is calculated, using an optimized version of a regularized inversion method, for each pixel across the six channels at different times, resulting in emission measure maps and movies in a variety of temperature ranges. Results: We find that the core of the erupting plasmoid is hot (8-11, 11-14 MK) with a similarly hot filamentary "stem" structure connecting it to the lower atmosphere, which could be interpreted as the current sheet in the flux rope model, though is wider than these models suggest. The velocity of the leading edge of the eruption is 597-664 km s-1 in the temperature range ≥3-4 MK and between 1029-1246 km s-1 for ≤2-3 MK. We estimate the density (in 11-14 MK) of the erupting core and stem during the impulsive phase to be about 3 × 109 cm-3, 6 × 109 cm-3, 9 × 108 cm-3 in the plasmoid core, stem, and surrounding envelope of material. This gives thermal energy estimates of 5 × 1029 erg, 1 × 1029 erg, and 2 × 1030 erg. The kinetic energy for the core and envelope is slightly lower. The thermal energy of the core and current sheet grows during the eruption, suggesting continuous influx of energy presumably via reconnection. Conclusions: The combination of the optimized regularized inversion method and SDO/AIA data allows the multi-thermal characteristics (i.e. velocity, density, and thermal energies) of the

  13. A prospective evaluation of occult disorders in obstructed defecation using the 'iceberg diagram'.

    Science.gov (United States)

    Pescatori, M; Spyrou, M; Pulvirenti d'Urso, A

    2007-06-01

    Surgical treatment of constipation and obstructed defecation (OD) carries frequent recurrences, as OD is an 'iceberg syndrome' characterized by 'underwater rocks' or occult diseases which may affect the outcome of surgery. The aim of this study was to evaluate occult disorders, in order to alert the clinician of these and minimize failures. One hundred consecutive constipated patients with OD symptoms, 81 women, median age 52 years, underwent perineal examination, proctoscopy, anorectal manometry and anal/vaginal ultrasound (US). Anorectal physiology and imaging tests were also carried out when indicated, as well as psychological and urogynaecological consultations. Symptoms were graded using a modified 1-20 constipation score. Both evident (e.g. rectocele) and occult (e.g. anismus) diseases were prospectively evaluated using a novel 'iceberg diagram'. The type of treatment, whether conservative or surgical, was also recorded. Fifty-four (54%) patients had both mucosal prolapse and rectocele. All patients had at least two occult OD-related diseases, 66 patients had at least three of them: anxiety-depression, anismus and rectal hyposensation were the most frequent (66%, 44% and 33%, respectively). The median constipation score was 11 (range 2-20), the median number of 'occult disorders' was 5 (range 2-8). Conservative treatment was carried out in most cases. Surgery was carried out in 14 (14%) patients. The novel 'iceberg diagram' allowed the adequate evaluation of OD-related occult diseases and better selection of patients for treatment. Most were managed conservatively, and only a minority were treated by surgery.

  14. Regularized Statistical Analysis of Anatomy

    DEFF Research Database (Denmark)

    Sjöstrand, Karl

    2007-01-01

    This thesis presents the application and development of regularized methods for the statistical analysis of anatomical structures. Focus is on structure-function relationships in the human brain, such as the connection between early onset of Alzheimer’s disease and shape changes of the corpus...... and mind. Statistics represents a quintessential part of such investigations as they are preluded by a clinical hypothesis that must be verified based on observed data. The massive amounts of image data produced in each examination pose an important and interesting statistical challenge...... efficient algorithms which make the analysis of large data sets feasible, and gives examples of applications....

  15. Regularization methods in Banach spaces

    CERN Document Server

    Schuster, Thomas; Hofmann, Bernd; Kazimierski, Kamil S

    2012-01-01

    Regularization methods aimed at finding stable approximate solutions are a necessary tool to tackle inverse and ill-posed problems. Usually the mathematical model of an inverse problem consists of an operator equation of the first kind and often the associated forward operator acts between Hilbert spaces. However, for numerous problems the reasons for using a Hilbert space setting seem to be based rather on conventions than on an approprimate and realistic model choice, so often a Banach space setting would be closer to reality. Furthermore, sparsity constraints using general Lp-norms or the B

  16. Academic Training Lecture - Regular Programme

    CERN Multimedia

    PH Department

    2011-01-01

    Regular Lecture Programme 9 May 2011 ACT Lectures on Detectors - Inner Tracking Detectors by Pippa Wells (CERN) 10 May 2011 ACT Lectures on Detectors - Calorimeters (2/5) by Philippe Bloch (CERN) 11 May 2011 ACT Lectures on Detectors - Muon systems (3/5) by Kerstin Hoepfner (RWTH Aachen) 12 May 2011 ACT Lectures on Detectors - Particle Identification and Forward Detectors by Peter Krizan (University of Ljubljana and J. Stefan Institute, Ljubljana, Slovenia) 13 May 2011 ACT Lectures on Detectors - Trigger and Data Acquisition (5/5) by Dr. Brian Petersen (CERN) from 11:00 to 12:00 at CERN ( Bldg. 222-R-001 - Filtration Plant )

  17. Extent and kinetics of recovery of occult spinal cord injury

    International Nuclear Information System (INIS)

    Ang, K. Kian; Jiang, G.-L.; Feng Yan; Stephens, L. Clifton; Tucker, Susan L.; Price, Roger E.

    2001-01-01

    Purpose: To obtain clinically useful quantitative data on the extent and kinetics of recovery of occult radiation injury in primate spinal cord, after a commonly administered elective radiation dose of 44 Gy, given in about 2 Gy per fraction. Methods and Materials: A group of 56 rhesus monkeys was assigned to receive two radiation courses to the cervical and upper thoracic spinal cord, given in 2.2 Gy per fraction. The dose of the initial course was 44 Gy in all monkeys. Reirradiation dose was 57.2 Gy, given after 1-year (n 16) or 2-year (n = 20) intervals, or 66 Gy, given after 2-year (n = 4) or 3-year (n = 14) intervals. Two animals developed intramedullary tumors before reirradiation and, therefore, did not receive a second course. The study endpoint was myeloparesis, manifesting predominantly as lower extremity weakness and decrease in balance, occurring within 2.5 years after reirradiation, complemented by histologic examination of the spinal cord. The data obtained were analyzed along with data from a previous study addressing single-course tolerance, and data from a preliminary study of reirradiation tolerance. Results: Only 4 of 45 monkeys completing the required observation period (2-2.5 years after reirradiation, 3-5.5 years total) developed myeloparesis. The data revealed a substantial recovery of occult injury induced by 44 Gy within the first year, and suggested additional recovery between 1 and 3 years. Fitting the data with a model, assuming that all (single course and reirradiation) dose-response curves were parallel, yielded recovery estimates of 33.6 Gy (76%), 37.6 Gy (85%), and 44.6 Gy (101%) of the initial dose, after 1, 2, and 3 years, respectively, at the 5% incidence (D 5 ) level. The most conservative estimate, using a model in which it was assumed that there was no recovery between 1 and 3 years following initial irradiation and that the combined reirradiation curve was not necessarily parallel to the single-course curve, still showed an

  18. RES: Regularized Stochastic BFGS Algorithm

    Science.gov (United States)

    Mokhtari, Aryan; Ribeiro, Alejandro

    2014-12-01

    RES, a regularized stochastic version of the Broyden-Fletcher-Goldfarb-Shanno (BFGS) quasi-Newton method is proposed to solve convex optimization problems with stochastic objectives. The use of stochastic gradient descent algorithms is widespread, but the number of iterations required to approximate optimal arguments can be prohibitive in high dimensional problems. Application of second order methods, on the other hand, is impracticable because computation of objective function Hessian inverses incurs excessive computational cost. BFGS modifies gradient descent by introducing a Hessian approximation matrix computed from finite gradient differences. RES utilizes stochastic gradients in lieu of deterministic gradients for both, the determination of descent directions and the approximation of the objective function's curvature. Since stochastic gradients can be computed at manageable computational cost RES is realizable and retains the convergence rate advantages of its deterministic counterparts. Convergence results show that lower and upper bounds on the Hessian egeinvalues of the sample functions are sufficient to guarantee convergence to optimal arguments. Numerical experiments showcase reductions in convergence time relative to stochastic gradient descent algorithms and non-regularized stochastic versions of BFGS. An application of RES to the implementation of support vector machines is developed.

  19. Regularized Label Relaxation Linear Regression.

    Science.gov (United States)

    Fang, Xiaozhao; Xu, Yong; Li, Xuelong; Lai, Zhihui; Wong, Wai Keung; Fang, Bingwu

    2018-04-01

    Linear regression (LR) and some of its variants have been widely used for classification problems. Most of these methods assume that during the learning phase, the training samples can be exactly transformed into a strict binary label matrix, which has too little freedom to fit the labels adequately. To address this problem, in this paper, we propose a novel regularized label relaxation LR method, which has the following notable characteristics. First, the proposed method relaxes the strict binary label matrix into a slack variable matrix by introducing a nonnegative label relaxation matrix into LR, which provides more freedom to fit the labels and simultaneously enlarges the margins between different classes as much as possible. Second, the proposed method constructs the class compactness graph based on manifold learning and uses it as the regularization item to avoid the problem of overfitting. The class compactness graph is used to ensure that the samples sharing the same labels can be kept close after they are transformed. Two different algorithms, which are, respectively, based on -norm and -norm loss functions are devised. These two algorithms have compact closed-form solutions in each iteration so that they are easily implemented. Extensive experiments show that these two algorithms outperform the state-of-the-art algorithms in terms of the classification accuracy and running time.

  20. Solar systems

    International Nuclear Information System (INIS)

    1987-01-01

    During 1986 the South African Astronomical Observatory (SAAO) was part of a collaboration that studied Halley's Comet. At SAAO, direct photographs and infrared photometry of Halley's Comet were obtained as part of a world-wide network. Various occultations of planets were also studied in 1986. 1 fig

  1. Solar building

    OpenAIRE

    Zhang, Luxin

    2014-01-01

    In my thesis I describe the utilization of solar energy and solar energy with building integration. In introduction it is also mentioned how the solar building works, trying to make more people understand and accept the solar building. The thesis introduces different types of solar heat collectors. I compared the difference two operation modes of solar water heating system and created examples of solar water system selection. I also introduced other solar building applications. It is conv...

  2. Solar energy

    International Nuclear Information System (INIS)

    Anon.

    1992-01-01

    This chapter discusses the role solar energy may have in the energy future of the US. The topics discussed in the chapter include the solar resource, solar architecture including passive solar design and solar collectors, solar-thermal concentrating systems including parabolic troughs and dishes and central receivers, photovoltaic cells including photovoltaic systems for home use, and environmental, health and safety issues

  3. Detection of Occult Erythrocytic Membrane Damages upon Pharmacological Exposures

    Directory of Open Access Journals (Sweden)

    P. Yu. Alekseyeva

    2007-01-01

    Full Text Available Blood administration of pharmaceuticals may cause occult effects of these agents on erythrocytic membranes. These effects may damage and cause additional membrane defects, but may strengthen. The type and degree of the effects of an agent were detected by calibrated irreversible electroporation with a pulsed electric field (PEF. The paper considers the erythrocytic membranous effects of a wide concentration range of agents used in anesthesiology, such as esmerone, tracrium, and mar-caine-adrenaline. Under the action of PEF and esmerone at the normal concentration N, the rate of erythrocytic hemolysis increased by several times as compared with the control. The similar effect also occurred when esmerone was added at the concentration C=10N. Tracrium exerted a fixing effect on erythrocytic membranes. Upon a combined exposure to PEF and tracrium in the normal concentration C=N; erythrocytic hemolysis was slow. So was with the concentration C=10N. The rate of hemolysis of the red blood cells subjected to a combined action of marcaine adrenaline at the normal concentration C=N and even at the concentration C=10N and PEF was comparable with the hemolytic rate of the reference suspension. 

  4. Exploring atmospheric blocking with GPS radio occultation observations

    Directory of Open Access Journals (Sweden)

    L. Brunner

    2016-04-01

    Full Text Available Atmospheric blocking has been closely investigated in recent years due to its impact on weather and climate, such as heat waves, droughts, and flooding. We use, for the first time, satellite-based observations from Global Positioning System (GPS radio occultation (RO and explore their ability to resolve blocking in order to potentially open up new avenues complementing models and reanalyses. RO delivers globally available and vertically highly resolved profiles of atmospheric variables such as temperature and geopotential height (GPH. Applying a standard blocking detection algorithm, we find that RO data robustly capture blocking as demonstrated for two well-known blocking events over Russia in summer 2010 and over Greenland in late winter 2013. During blocking episodes, vertically resolved GPH gradients show a distinct anomalous behavior compared to climatological conditions up to 300 hPa and sometimes even further up into the tropopause. The accompanying increase in GPH of up to 300 m in the upper troposphere yields a pronounced tropopause height increase. Corresponding temperatures rise up to 10 K in the middle and lower troposphere. These results demonstrate the feasibility and potential of RO to detect and resolve blocking and in particular to explore the vertical structure of the atmosphere during blocking episodes. This new observation-based view is available globally at the same quality so that blocking in the Southern Hemisphere can also be studied with the same reliability as in the Northern Hemisphere.

  5. Occult radiological effects of lipomatosis of the lumbosacral plexus

    Energy Technology Data Exchange (ETDEWEB)

    Mahan, Mark A. [Barrow Neurological Institute, Phoenix, AZ (United States); Howe, B.M.; Amrami, Kimberly K. [Mayo Clinic, Department of Radiology, Rochester, MN (United States); Spinner, Robert J. [Mayo Clinic, Department of Neurosurgery, Rochester, MN (United States); Mayo Clinic, Department of Orthopedics, Rochester, MN (United States); Mayo Clinic, Rochester, MN (United States)

    2014-07-15

    Lipomatosis of nerve (LN) is a condition of massive peripheral nerve enlargement frequently associated with hypertrophy within the distribution of the nerve, and most commonly affecting the distal limbs. We sought to understand if LN of the lumbosacral plexus would be associated with the trophic effects of LN on surrounding tissue within the pelvis, which may be clinically occult, but present on MRI. Fifty-one cases of LN, confirmed by pathology or pathognomonic appearance on MRI, were reviewed. Patients with LN of the sciatic nerve were investigated for radiological signs suggestive of overgrowth. Five patients had involvement of the sciatic nerve, 4 of whom had MR imaging of the pelvis. Three patients had LN involving the lumbosacral plexus, and one patient had isolated involvement of the sciatic nerve. All patients with involvement of the lumbosacral plexus demonstrated previously unrecognized evidence of nerve territory overgrowth in the pelvis, including: LN, profound adipose proliferation, muscle atrophy and fatty infiltration, and bone hypertrophy and ankylosis. The patient with LN involving the intrapelvic sciatic nerve, but not the lumbosacral plexus did not demonstrate any radiological evidence of pelvic overgrowth. LN is broader in anatomical reach than previously understood. Proximal plexal innervation may be involved, with a consequent effect on axial skeleton and intrapelvic structures. (orig.)

  6. Occult hepatitis B infection and transfusion-transmission risk.

    Science.gov (United States)

    Candotti, D; Boizeau, L; Laperche, S

    2017-09-01

    Advances in serology and viral nucleic acid testing (NAT) over the last decades significantly reduced the risk of transfusion-transmitted hepatitis B virus (HBV). The combination of HBsAg testing and NAT efficiently prevents the majority of HBV transmission. However, a specific residual risk remains associated with extremely low viral DNA levels in blood donors with occult HBV infection (OBI) that are intermittently or not detectable even by highly sensitive individual donation (ID) NAT. Studies have reported HBV transfusion-transmission with blood components from donors with OBI that contained low amount of viruses (transfusion-transmission seems to depend on a combination of several factors including the volume of plasma associated with the infected blood components transfused, the anti-HBV immune status of both recipient and donor, and possibly the viral fitness of the infecting HBV strain. Models based on clinical and experimental evidences estimate a residual transmission risk of 3-14% associated with OBI donations testing HBsAg and ID-NAT non-reactive. Anti-HBc testing has the potential to improve further blood safety but it may also compromise blood availability in settings with medium/high HBV prevalence. Pathogen reduction procedures might be considered. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

  7. Ectoparasites of the occult bat, Myotis occultus (Chiroptera: Vespertilionidae)

    Science.gov (United States)

    Valdez, Ernest W.; Ritzi, Christopher M.; Whitaker, John O.

    2009-01-01

    Only a single previous study has examined ectoparasites of the occult bat (Myotis occultus), from which only 2 species of fleas were identified. For our study, we examined 202 individuals, 52 fresh hosts and 150 museum specimens, from New Mexico and southern Colorado for ectoparasites. We recorded 2158 ectoparasites, 634 from fresh hosts and 1524 from museum specimens. Ectoparasites belonged to 10 families and 13 genera of insect or acari and represent new host and locality records. In general, ectoparasites collected from fresh hosts and museum specimens were represented by 4 major species of mite: Macronyssus crosbyi, Alabidocarpus calcaratus, Acanthophthirius lucifugus, and Alabidocarpus nr. eptesicus. From our study, we found fresh hosts to have significantly greater prevalence values for Myodopsylla gentilis (flea), Chiroptonyssus robustipes (mite), and Leptotrombidium myotis (chigger), whereas museum specimens had significantly greater prevalence values for A. calcaratus(mite) and A. nr. eptesicus (mite). There were no significant differences between prevalence values for 4 mites including M. crosbyi, A. lucifugus, Pteracarus nr. minutus, and Cryptonyssussp. Our study represents the only extensive study of ectoparasites on M. occultus and provides evidence for the importance of examining fresh hosts and museum specimens in future ectoparasite studies.

  8. MRI of occult sacral insufficiency fractures following radiotherapy

    International Nuclear Information System (INIS)

    Mammone, J.F.; Schweitzer, M.E.

    1995-01-01

    Following radiation therapy, marrow abnormalities noted on magnetic resonance imaging (MRI) are frequent and may mimic metastases. Specific radiotherapy changes are usually easily identifiable; however, traumatic lesions cause more interpretive difficulties. We assessed the incidence and MRI characteristics of insufficiency fractures in this population. During a 5-year span (1987-1991), 546 patients received pelvic radiotherapy for primary malignancies. MRI was performed in 25 of these patients at least 3 months after treatment. The mean dose in this group was 53 Gy. These MRI scans were retrospectively reviewed for the appearance of the sacrum with particular attention to the presence of insufficiency fractures. This was correlated with clinical course and scintigraphic findings. Presumed insufficiency fractures on MRI paralleled the sacral side of the sacroiliac joint, enhanced with Gd-DTPA, were most prominent or initially seen anteriorly, and had ill-defined margins on all imaging sequences. The incidence of occult sacral insufficiency fractures was at least 20%. Insufficiency fractures of the sacrum in the post-radiotherapy patient are a relatively frequent occurrence which can mimic metastases. Consideration of this phenomenon and knowledge of differential features may avoid overdiagnosis of osseous metastases. (orig.)

  9. Assimilation of GNSS radio occultation observations in GRAPES

    Science.gov (United States)

    Liu, Y.; Xue, J.

    2014-07-01

    This paper reviews the development of the global navigation satellite system (GNSS) radio occultation (RO) observations assimilation in the Global/Regional Assimilation and PrEdiction System (GRAPES) of China Meteorological Administration, including the choice of data to assimilate, the data quality control, the observation operator, the tuning of observation error, and the results of the observation impact experiments. The results indicate that RO data have a significantly positive effect on analysis and forecast at all ranges in GRAPES not only in the Southern Hemisphere where conventional observations are lacking but also in the Northern Hemisphere where data are rich. It is noted that a relatively simple assimilation and forecast system in which only the conventional and RO observation are assimilated still has analysis and forecast skill even after nine months integration, and the analysis difference between both hemispheres is gradually reduced with height when compared with NCEP (National Centers for Enviromental Prediction) analysis. Finally, as a result of the new onboard payload of the Chinese FengYun-3 (FY-3) satellites, the research status of the RO of FY-3 satellites is also presented.

  10. Information content in reflected signals during GPS Radio Occultation observations

    Science.gov (United States)

    Aparicio, Josep M.; Cardellach, Estel; Rodríguez, Hilda

    2018-04-01

    The possibility of extracting useful information about the state of the lower troposphere from the surface reflections that are often detected during GPS radio occultations (GPSRO) is explored. The clarity of the reflection is quantified, and can be related to properties of the surface and the low troposphere. The reflected signal is often clear enough to show good phase coherence, and can be tracked and processed as an extension of direct non-reflected GPSRO atmospheric profiles. A profile of bending angle vs. impact parameter can be obtained for these reflected signals, characterized by impact parameters that are below the apparent horizon, and that is a continuation at low altitude of the standard non-reflected bending angle profile. If there were no reflection, these would correspond to tangent altitudes below the local surface, and in particular below the local mean sea level. A forward operator is presented, for the evaluation of the bending angle of reflected GPSRO signals, given atmospheric properties as described by a numerical weather prediction system. The operator is an extension, at lower impact parameters, of standard bending angle operators, and reproduces both the direct and reflected sections of the measured profile. It can be applied to the assimilation of the reflected section of the profile as supplementary data to the direct section. Although the principle is also applicable over land, this paper is focused on ocean cases, where the topographic height of the reflecting surface, the sea level, is better known a priori.

  11. From inactive to regular jogger

    DEFF Research Database (Denmark)

    Lund-Cramer, Pernille; Brinkmann Løite, Vibeke; Bredahl, Thomas Viskum Gjelstrup

    study was conducted using individual semi-structured interviews on how a successful long-term behavior change had been achieved. Ten informants were purposely selected from participants in the DANO-RUN research project (7 men, 3 women, average age 41.5). Interviews were performed on the basis of Theory...... of Planned Behavior (TPB) and The Transtheoretical Model (TTM). Coding and analysis of interviews were performed using NVivo 10 software. Results TPB: During the behavior change process, the intention to jogging shifted from a focus on weight loss and improved fitness to both physical health, psychological......Title From inactive to regular jogger - a qualitative study of achieved behavioral change among recreational joggers Authors Pernille Lund-Cramer & Vibeke Brinkmann Løite Purpose Despite extensive knowledge of barriers to physical activity, most interventions promoting physical activity have proven...

  12. Tessellating the Sphere with Regular Polygons

    Science.gov (United States)

    Soto-Johnson, Hortensia; Bechthold, Dawn

    2004-01-01

    Tessellations in the Euclidean plane and regular polygons that tessellate the sphere are reviewed. The regular polygons that can possibly tesellate the sphere are spherical triangles, squares and pentagons.

  13. On the equivalence of different regularization methods

    International Nuclear Information System (INIS)

    Brzezowski, S.

    1985-01-01

    The R-circunflex-operation preceded by the regularization procedure is discussed. Some arguments are given, according to which the results may depend on the method of regularization, introduced in order to avoid divergences in perturbation calculations. 10 refs. (author)

  14. The uniqueness of the regularization procedure

    International Nuclear Information System (INIS)

    Brzezowski, S.

    1981-01-01

    On the grounds of the BPHZ procedure, the criteria of correct regularization in perturbation calculations of QFT are given, together with the prescription for dividing the regularized formulas into the finite and infinite parts. (author)

  15. The value of MR imaging of PDFASAT sequence in the diagnosis of extremities occult fractures

    International Nuclear Information System (INIS)

    Lu Lingquan; Xu Mingshen; Wu Qianzhi; Mao Chunnan; Wang Shuzi; Zhou Xingfan; Wang Liping

    2004-01-01

    Objective: To investigate the value of MR imaging of proton density weighted-fat saturated (PDFASAT) sequence in detecting the occult fracture of extremities. Methods: Thirty-one patients with acute trauma were studied using radiography and MR imaging within 45 days. MR sequences included FSE T 1 WI, T 2 WI, and PDFASAT. 21 occult fractures occurred in the knee joint, 6 in the hip joint, 1 in the elbow joint, 2 in the shoulder, and 1 in the ankle. Results: All 31 cases had normal radiographic results. 10 cases with proximal fibula, 4 with proximal tibia and 7 with femur condyle occult fractures were found in 21 knee joint acute trauma cases. 2 cases with intertrochanteric, 2 with femoral neck and 2 with cotyle occult fractures were found in 6 hip joint trauma cases. 2 proximal humerus occult fractures were found in 2 shoulder cases. 1 distal humerus and 1 distal fibula occult fracture was found in elbow and ankle cases. MR imaging demonstrated irregular linear low signal in the subcortical region on both T 1 WI and T 2 WI, and high signal changes around low signal were seen on T 2 WI in some cases. The high signal in PDFASAT sequence was more remarkable and wider than that on both T 1 WI and T 2 WI. Conclusion: MR imaging could determine the diagnosis of acute and chronic occult fractures. MRI should be the next choice when plain films fail to reveal suspected fractures in setting of suggestive symptoms and positive physical examination. PDFASAT would be the best effective sequence among the T 1 WI, T 2 WI, and PDFASAT. (author)

  16. Application of Turchin's method of statistical regularization

    Science.gov (United States)

    Zelenyi, Mikhail; Poliakova, Mariia; Nozik, Alexander; Khudyakov, Alexey

    2018-04-01

    During analysis of experimental data, one usually needs to restore a signal after it has been convoluted with some kind of apparatus function. According to Hadamard's definition this problem is ill-posed and requires regularization to provide sensible results. In this article we describe an implementation of the Turchin's method of statistical regularization based on the Bayesian approach to the regularization strategy.

  17. Regular extensions of some classes of grammars

    NARCIS (Netherlands)

    Nijholt, Antinus

    Culik and Cohen introduced the class of LR-regular grammars, an extension of the LR(k) grammars. In this report we consider the analogous extension of the LL(k) grammers, called the LL-regular grammars. The relations of this class of grammars to other classes of grammars are shown. Every LL-regular

  18. Thermal infrared laser heterodyne spectroradiometry for solar occultation atmospheric CO2 measurements

    Science.gov (United States)

    Hoffmann, Alex; Macleod, Neil A.; Huebner, Marko; Weidmann, Damien

    2016-12-01

    This technology demonstration paper reports on the development, demonstration, performance assessment, and initial data analysis of a benchtop prototype quantum cascade laser heterodyne spectroradiometer, operating within a narrow spectral window of ˜ 1 cm-1 around 953.1 cm-1 in transmission mode and coupled to a passive Sun tracker. The instrument has been specifically designed for accurate dry air total column, and potentially vertical profile, measurements of CO2. Data from over 8 months of operation in 2015 near Didcot, UK, confirm that atmospheric measurements with noise levels down to 4 times the shot noise limit can be achieved with the current instrument. Over the 8-month period, spectra with spectral resolutions of 60 MHz (0.002 cm-1) and 600 MHz (0.02 cm-1) have been acquired with median signal-to-noise ratios of 113 and 257, respectively, and a wavenumber calibration uncertainty of 0.0024 cm-1.Using the optimal estimation method and RFM as the radiative transfer forward model, prior analysis and theoretical benchmark modelling had been performed with an observation system simulator (OSS) to target an optimized spectral region of interest. The selected narrow spectral window includes both CO2 and H2O ro-vibrational transition lines to enable the measurement of dry air CO2 column from a single spectrum. The OSS and preliminary retrieval results yield roughly 8 degrees of freedom for signal (over the entire state vector) for an arbitrarily chosen a priori state with relatively high uncertainty ( ˜ 4 for CO2). Preliminary total column mixing ratios obtained are consistent with GOSAT monthly data. At a spectral resolution of 60 MHz with an acquisition time of 90 s, instrumental noise propagation yields an error of around 1.5 ppm on the dry air total column of CO2, exclusive of biases and geophysical parameters errors at this stage.

  19. Fecal occult blood test for colorectal cancer screening: an evidence-based analysis.

    Science.gov (United States)

    2009-01-01

    The colorectal cancer (CRC) screening project was undertaken by the Medical Advisory Secretariat (MAS) in collaboration with the Cancer Care Ontario (CCO).In November 2007, the Ontario Health Technology Advisory Committee (OHTAC) MAS to conduct an evidence-based analysis of the available data with respect to colorectal cancer diagnosis and prevention. The general purpose of the project was to investigate the effectiveness, cost effectiveness, and safety of the various methods and techniques used for colorectal cancer screening in average risk people, 50 years of age and older.The options currently offered for colorectal cancer screening were reviewed and five technologies were selected for review:Computed tomographic (CT) colonographyMagnetic resonance (MR) colonographyWireless capsule endoscopy (PillCam Colon)Fecal occult blood test (FOBT)Flexible sigmoidoscopyIn this review, colonoscopy was considered as the "gold standard" technique by which the effectiveness of all other modalities could be evaluated. An economic analysis was also conducted to determine cost-effectiveness of different screening modalities.Evidence-based analyses have been prepared for each of these technologies, as well as summary document that includes an economic analysis, all of which are presented at the MAS Web site: http://www.health.gov.on.ca/english/providers/program/mas/tech/techmn.html The objective of this evidence review is to examine the effectiveness and cost-effectiveness of fecal occult blood testing (FOBT), including guaiac FOBT (gFOBT) and immunochemical FOBT (iFOBT), for use in colorectal cancer (CRC) screening in asymptomatic, average-risk adults. Specifically: Is the use of gFOBT or iFOBT associated with a reduction in CRC and overall mortality?What are the sensitivity and specificity of gFOBT and iFOBT for the detection of 1) CRC and 2) large polyps (≥ 1 cm)? CRC is the most common cause of non-tobacco related cancer death in Canada. It has been estimated that in 2007, 7

  20. Recurring sets of recurring starspot occultations on exoplanet host Qatar-2

    Science.gov (United States)

    Močnik, T.; Southworth, J.; Hellier, C.

    2017-10-01

    We announce the detection of recurring sets of recurring starspot occultation events in the short-cadence K2 light curve of Qatar-2, a K dwarf star transited every 1.34 d by a hot Jupiter. In total, we detect 34 individual starspot occultation events, caused by five different starspots, occulted in up to five consecutive transits or after a full stellar rotation. The longest recurring set of recurring starspot occultations spans over three stellar rotations, setting a lower limit for the longest starspot lifetime of 58 d. Starspot analysis provided a robust stellar rotational period measurement of 18.0 ± 0.2 d and indicates that the system is aligned, having a sky-projected obliquity of 0° ± 8°. A pronounced rotational modulation in the light curve has a period of 18.2 ± 1.6 d, in agreement with the rotational period derived from the starspot occultations. We tentatively detect an ellipsoidal modulation in the phase curve, with a semi-amplitude of 18 ppm, but cannot exclude the possibility that this is the result of red noise or imperfect removal of the rotational modulation. We detect no transit-timing and transit-duration variations with upper limits of 15 s and 1 min, respectively. We also reject any additional transiting planets with transit depths above 280 ppm in the orbital period region 0.5-30 d.

  1. Retrieval of Electron Density Profile for KOMPSAT-5 GPS Radio Occultation

    Directory of Open Access Journals (Sweden)

    Woo-Kyoung Lee

    2007-12-01

    Full Text Available The AOPOD (Atmosphere Occultation and Precision Orbit Determination system, the secondary payload of KOMPSAT (KOrea Multi-Purpose SATellite-5 scheduled to be launched in 2010, shall provide GPS radio occultation data. In this paper, we simulated the GPS radio occultation characteristic of KOMPSAT-5 and retrieved electron density profiles using KROPS (KASI Radio Occultation Processing Software. The electron density retrieved from CHAMP (CHAllenging Minisatellite Payload GPS radio occultation data on June 20, 2004 was compared with IRI (International Reference Ionosphere - 2001, PLP (Planar Langmuir Probe, and ionosonde measurements. When the result was compared with ionosonde measurements, the discrepancies were 5 km on the F_2 peak height (hmF_2 and 3×10^{10} el/m^3 on the electron density of the F_2 peak height (NmF_2. By comparing with the Langmuir Probe measurements of CHAMP satellite (PLP, both agrees with 1.6×10^{11} el/m^3 at the height of 365.6 km.

  2. [Surgical Diagnosis and Treatment of Primary Hyperthyroidism Complicated with Occult Thyroid Carcinoma].

    Science.gov (United States)

    Wu, Xin; Yu, Jian-chun; Kang, Wei-ming; Ma, Zhi-qiang; Ye, Xin

    2015-08-01

    To evaluate the surgical diagnosis and treatment of primary hyperthyroidism complicated with occult thyroid carcinoma. Data of 51 cases of primary hyperthyroidism complicated with occult thyroid carcinoma admitted during January 2004 to November 2014 were analyzed retrospectively. The incidence of occult thyroid carcinoma was 5.03% in hyperthyroidism,and 47 cases (92.16%) were female. The preoperative diagnosis of all these 51 cases was primary hyperthyroidism and 11 cases were diagnosed thyroid carcinoma at the same time;25 cases were diagnosed thyroid carcinoma by frozen section and the remaining 26 cases were diagnosed by postoperative pathology. Finally,26 cases underwent subtotal thyroidectomy,4 cases underwent total thyroidectomy, and 21 cases underwent total thyroidectomy with lymphadenectomy. The tumor size ranged from 0.1 to 1.0 cm [mean:(0.63 ± 0.35) cm]. The lesions were less than or equal to 0.5 cm in 28 cases (54.9%). The follow-up lasted from 1 to 121 months [mean:(28.6 ± 22.7)months] in 43 patients,and all of them survived. Primary hyperthyroidism complicated with occult thyroid carcinoma is commonly found in female patients. Preoperative diagnosis is difficult. Ultrasound is the major examining method. Frozen section can increase the detection rate. The postoperative prognosis of hyperthyroidism complicated with occult thyroid carcinoma is satisfactory.

  3. Prevalence of occult hepatitis B virus infection in haemodialysis patients from central Greece

    Science.gov (United States)

    Mina, Paraskevi; Georgiadou, Sarah P; Rizos, Christos; Dalekos, George N; Rigopoulou, Eirini I

    2010-01-01

    AIM: To assess the hepatitis B virus (HBV)-DNA and the prevalence of occult HBV infection in end-stage renal failure (ESRF) patients from Central Greece. METHODS: Sera from 366 ESRF patients attending five out of six dialysis units from Central Greece were investigated for HBV-DNA by real-time polymerase chain reaction. Only serum samples with repeatedly detectable HBV-DNA were considered positive. IgG antibodies to hepatitis C virus (anti-HCV) were tested by a third generation enzyme linked immunosorbent assay (ELISA), while IgG antibodies to hepatitis E virus (anti-HEV) were tested by two commercially available ELISAs. RESULTS: HBV-DNA was detected in 15/366 patients (4.1%) and HBsAg in 20/366 (5.5%). The prevalence of occult HBV infection was 0.9% (3/346 HBsAg-negative patients). Occult HBV was not associated with a specific marker of HBV infection or anti-HCV or anti-HEV reactivity. There was no significant difference in HBV-DNA titres, demographic and biochemical features, between patients with occult HBV infection and those with HBsAg-positive chronic HBV infection. CONCLUSION: In central Greece, 4% of ESRF patients had detectable HBV-DNA, though in this setting, the prevalence of occult HBV seems to be very low (0.9%). PMID:20066742

  4. Outcome of Concurrent Occult Hemothorax and Pneumothorax in Trauma Patients Who Required Assisted Ventilation

    Directory of Open Access Journals (Sweden)

    Ismail Mahmood

    2015-01-01

    Full Text Available Background. The management and outcomes of occult hemopneumothorax in blunt trauma patients who required mechanical ventilation are not well studied. We aimed to study patients with occult hemopneumothorax on mechanical ventilation who could be carefully managed without tube thoracostomy. Methods. Chest trauma patients with occult hemopneumothorax who were on mechanical ventilation were prospectively evaluated. The presence of hemopneumothorax was confirmed by CT scanning. Hospital length of stay, complications, and outcome were recorded. Results. A total of 56 chest trauma patients with occult hemopneumothorax who were on ventilatory support were included with a mean age of 36 ± 13 years. Hemopneumothorax was managed conservatively in 72% cases and 28% underwent tube thoracostomy as indicated. 29% of patients developed pneumonia, 16% had Acute Respiratory Distress Syndrome (ARDS, and 7% died. Thickness of hemothorax, duration of mechanical ventilation, and development of ARDS were significantly associated with tube thoracostomy in comparison to no-chest tube group. Conclusions. The majority of occult hemopneumothorax can be carefully managed without tube thoracostomy in patients who required positive pressure ventilation. Tube thoracotomy could be restricted to those who had evidence of increase in the size of the hemothorax or pneumothorax on follow-up chest radiographs or developed respiratory compromise.

  5. [Prevalence of occult hepatitis B virus infection and its phylogenetic features among mother-teenager pairs].

    Science.gov (United States)

    Dong, Xiao-lian; Yao, Qing-qing; Wang, Xue-cai; Xu, Hai-tao; Wang, Xiao-li; Chen, Sheng-yu; Tang, Zhi-feng; Zheng, Ying-Jie

    2013-03-01

    Prevalence of occult hepatitis B virus (HBV) infection (OBI) was investigated in a paired mother-teenager population and HBV S gene variation including overt and occult HBV, was determined. A follow-up study based on an initial survey of 135 mother-teenager pairs was carried out through collection of questionnaires and blood samples HBsAg were detected by ELISA method, viral load by PCR amplification and HBV S gene by phylogenetic analysis. 102 pairs of subjects were followed-up. Blood samples from 94 mothers and 101 children were collected. OBI prevalence in mothers was 10.0% (6/60), significantly higher than 2.0% (2/101) in teenagers. Medians of viral load were 399.9 IU/ml and 247.6 IU/ml in overt and occult HBV strains, but without significant difference. 1 occult HBV strain belonged to genotype B with serotype adw while the other 7 were genotype C with serotype adr. 15 of the overt HBV strains belonged to genotype B with serotype adw and the other 8 were genotype C with serotype adr. Proportions of genotype-C strains were significantly higher in occult HBV strains than in overt HBV strains. OBI was seen in teenage-mother population.

  6. Disparities in the receipt of fecal occult blood test versus endoscopy among Filipino American immigrants.

    Science.gov (United States)

    Maxwell, Annette E; Danao, Leda L; Crespi, Catherine M; Antonio, Cynthia; Garcia, Gabriel M; Bastani, Roshan

    2008-08-01

    This report examines disparities associated with the type of colorectal screening test, fecal occult blood test versus endoscopy, within a particular racial/ethnic group, Filipino American immigrants. Between July 2005 and October 2006, Filipino Americans aged 50 to 75 years from 31 community organizations in Los Angeles completed a 15-minute survey in English (65%) or Filipino (35%). Of the 487 respondents included in this analysis, 257 (53%) had never received any type of colorectal cancer screening. Among the 230 subjects who had ever received a routine screening test, 78 had fecal occult blood test only (16% of the total sample), and 152 had endoscopy with or without fecal occult blood test (31% of the total sample). After controlling for access to care and key demographic variables in a multivariate analysis, only two characteristics distinguished between respondents who had fecal occult blood test only versus those who had endoscopy: acculturation, assessed by percent lifetime in the United States and language of interview, and income. Our data suggest a two-tier system, fecal occult blood test for less acculturated Filipino Americans with lower income versus endoscopy for Filipino immigrants with higher levels of acculturation and income. The disparity persists after adjusting for access to care. Instead of treating minority groups as monolithic, differences within groups need to be examined so that interventions can be appropriately targeted.

  7. Class of regular bouncing cosmologies

    Science.gov (United States)

    Vasilić, Milovan

    2017-06-01

    In this paper, I construct a class of everywhere regular geometric sigma models that possess bouncing solutions. Precisely, I show that every bouncing metric can be made a solution of such a model. My previous attempt to do so by employing one scalar field has failed due to the appearance of harmful singularities near the bounce. In this work, I use four scalar fields to construct a class of geometric sigma models which are free of singularities. The models within the class are parametrized by their background geometries. I prove that, whatever background is chosen, the dynamics of its small perturbations is classically stable on the whole time axis. Contrary to what one expects from the structure of the initial Lagrangian, the physics of background fluctuations is found to carry two tensor, two vector, and two scalar degrees of freedom. The graviton mass, which naturally appears in these models, is shown to be several orders of magnitude smaller than its experimental bound. I provide three simple examples to demonstrate how this is done in practice. In particular, I show that graviton mass can be made arbitrarily small.

  8. The Return of Congenital Rickets, Are We Missing Occult Cases?

    Science.gov (United States)

    Elidrissy, Abdelwahab T H

    2016-09-01

    Congenital rickets is the term given to fetus born with clinical features of rickets, but those born with biochemical evidence of rickets without obvious clinical features still can be considered occult congenital rickets. Some of the affected babies with this disease have the intrauterine rachitic environment, but a calcium trans-placental pump prevents the fetus from having clinical features of rickets. They may present with hypocalcemia few days after birth or later with more florid features of rickets. Congenital rickets cases born with florid features reported over the last 40 years are few and can be divided into two groups. The first due to severe maternal osteomalacia in which their bones were so decalcified to have enough calcium to be pumped to their fetus. Another group in which newborn babies were hypocalcemic due to other maternal diseases as malabsorption, celiac disease, pre-eclampsia, and prematurity. All inherited rickets cases per se, or as part of other syndromes can be considered congenital rickets. Most cases seen in our region are due to maternal vitamin D deficiency with symptoms becoming obvious when the infants are breastfed, or may present with hypocalcemic convulsions or craniotabes. This is a review of congenital rickets with the aim of shedding light on this potentially acute disease that needs more attention and awareness in the neonatal period to avoid rare serious complications as cardiomyopathy or myelofibrosis and the complications of hypocalcemic convulsions. Congenital rickets cases seen simulate a tip of an ice-burg and its prevention is an important issue, especially with the tremendous urbanization with tall buildings living in sun-deprived flats as the commonest type of residence leading to the increasing incidence of maternal osteomalacia and rickets.

  9. Clues to occult cancer in patients with ischemic stroke.

    Directory of Open Access Journals (Sweden)

    Suk Jae Kim

    Full Text Available BACKGROUND: We hypothesized that hidden malignancy could be detected in patients with cryptogenic stroke without active cancer when they showed the distinctive characteristics of cancer-related stroke. METHODS AND FINDINGS: Among 2,562 consecutive patients with acute ischemic stroke, patients with cryptogenic stroke were analyzed and categorized into two groups according to the presence of active cancer: cryptogenic stroke with active cancer (cancer-related stroke, CA-stroke group and without active cancer (CR-stroke group. Patients with active lung cancer without stroke were also recruited for comparison purposes (CA-control. Clinical factors, lesion patterns on diffusion-weighted MRI (DWI, and laboratory findings were analyzed among groups. A total of 348 patients with cryptogenic stroke were enrolled in this study. Among them, 71 (20.4% patients had active cancer at the time of stroke. The D-dimer levels were significantly higher in patients with CA-stroke than those with CR-stroke or CA-control (both p<0.001. Regarding lesion patterns, patients with CA-stroke mostly had multiple lesions in multiple vascular territories, while more than 80% of patients with CR-stroke had single/multiple lesions in a single vascular territory (P<0.001. D-dimer levels (OR 1.11 per 1 µg/mL increase; 95% CI 1.06-1.15; P<0.001 and DWI lesion patterns (OR 7.13; 95% CI 3.42-14.87; P<0.001 were independently associated with CA-stroke. Workup for hidden malignancy was performed during hospitalization in 10 patients who showed elevated D-dimer levels and multiple infarcts involving multiple vascular territories but had no known cancer, and it revealed hidden malignancies in all the patients. CONCLUSION: Patients with CA-stroke have distinctive D-dimer levels and lesion patterns. These characteristics can serve as clues to occult cancer in patients with cryptogenic stroke.

  10. Clinical presentations and MRI findings of angiographically occult vascular malformations

    International Nuclear Information System (INIS)

    Kida, Yoshihisa; Kobayashi, Tatsuya; Tanaka, Takayuki; Oyama, Hirofumi; Iwakoshi, Takayasu

    1994-01-01

    Various clinical features as well as MRI findings of AOVM (angiographically occult vascular malformation) were studied. Amongst out patients, since January 1988, there have been 30 cases of symptomatic AOVM (20 males, 10 females) including 4 cases with multiple lesions. The age ranged from 3 to 60 years of age, with a mean of 33.4 years. The locations of symptomatic lesions were in the cerebral hemisphere (15), the thalamus (4), the brain stem (8) and in the cerebellum (3). The initial presentations of these 30 cases were either by hemorrhage (18), convulsive seizure (9) or by progressive neurological deficits (3). The initial presentation was not related to the patient's age and the size of the lesion, but apparently related to the location of AOVM. Most of the lesions in the cerebral hemisphere presented seizures, but all of the lesions in the thalamus, the brain stem and the cerebellum disclosed hemorrhage as an initial presentation. In fact it was noticed that brain stem lesions tend to cause repetitive hemorrhage in a relatively short period. AOVM lesions were clearly visualized with T2-weighted MRI images, consisting of high intensity cores with surrounding low intensity rims. Most of the symptomatic lesions were partially enhanced by Gd-DTPA with varied intensity. Dynamic changes in size and enhancement pattern on MRI were occasionally seen, usually accompanied with episodes such as hemorrhage or neurological deterioration. Although AOVMs were angiographically negative some strands indicating draining veins were observed on MRI in several cases. In contrast, none of the nonsymptomatic lesions (22 lesions) demonstrated enhancement effects with Gd-DTPA. (author)

  11. Occult hepatitis B infection in children with chronic liver disease.

    Science.gov (United States)

    Srivastava, Anshu; Mathias, Amrita; Yachha, Surender K; Aggarwal, Rakesh

    2015-04-01

    Occult hepatitis B infection (OBI) may adversely affect the outcome of patients with chronic liver disease (CLD). There are no data on OBI and CLD in children. This study determined the prevalence and effect of OBI in HBsAg-negative CLD children. CLD children were prospectively evaluated with a demographic, clinical, and investigative proforma. All HBsAg-negative CLD cases were tested for exposure to hepatitis B (total anti-HBc, anti-HBs). Serum hepatitis B virus DNA was measured in exposed (total anti-HBc positive) patients. A total of 115 HBsAg-negative CLD children (59 boys, age 9.0±3.6 years) were enrolled. The etiology of CLD was known in 94 cases and 21 children had cryptogenic CLD. Of these, 45 (39.1%) had evidence of HBV exposure (23 total anti-HBc positive, 17 total anti-HBc and anti-HBs positive, five only anti-HBs positive without previous vaccination). The anti-HBc-positive children had a higher Child's score than the anti-HBc-negative children [11 (5-13) vs. 7 (5-13); P=0.00]. A total of 4/45 children had seropositive OBI with serum HBV DNA of 8, 36, 133, and 156 IU/ml, respectively. The proportion of total anti-HBc positivity (8/21 vs. 32/94; P=0.8) and OBI (2/21 vs. 2/94; P=0.1) was similar in cryptogenic CLD and known cause CLD. Seropositive OBI is infrequent in Indian children with CLD. The prevalence is similar in cryptogenic and CLD of known etiology.

  12. TWENTY-FIVE SUBARCSECOND BINARIES DISCOVERED BY LUNAR OCCULTATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Richichi, A. [National Astronomical Research Institute of Thailand, 191 Siriphanich Bldg., Huay Kaew Rd., Suthep, Muang, Chiang Mai 50200 (Thailand); Fors, O. [Departament Astronomia i Meteorologia and Institut de Ciencies del Cosmos (ICC), Universitat de Barcelona (UB/IEEC), Marti i Franques 1, E-08028 Barcelona (Spain); Cusano, F. [INAF-Osservatorio Astronomico di Bologna, Via Ranzani 1, I-40127 Bologna (Italy); Moerchen, M., E-mail: andrea4work@gmail.com [European Southern Observatory, Casilla 19001, Santiago 19 (Chile)

    2013-09-15

    We report on 25 subarcsecond binaries, detected for the first time by means of lunar occultations in the near-infrared (near-IR) as part of a long-term program using the ISAAC instrument at the ESO Very Large Telescope. The primaries have magnitudes in the range K = 3.8-10.4, and the companions in the range K = 6.4-12.1. The magnitude differences have a median value of 2.8, with the largest being 5.4. The projected separations are in the range 6-748 mas and with a median of 18 mas, or about three times less than the diffraction limit of the telescope. Among our binary detections are a pre-main-sequence star and an enigmatic Mira-like variable previously suspected to have a companion. Additionally, we quote an accurate first-time near-IR detection of a previously known wider binary. We discuss our findings on an individual basis as far as made possible by the available literature, and we examine them from a statistical point of view. We derive a typical frequency of binarity among field stars of Almost-Equal-To 10%, in the resolution and sensitivity range afforded by the technique ( Almost-Equal-To 0.''003 to Almost-Equal-To 0.''5, and K Almost-Equal-To 12 mag, respectively). This is in line with previous results using the same technique but we point out interesting differences that we can trace up to sensitivity, time sampling, and average distance of the targets. Finally, we discuss the prospects for further follow-up studies.

  13. Occult carcinoma discovered after simple hysterectomy treated with postoperative radiotherapy

    International Nuclear Information System (INIS)

    Crane, Christopher H.; Schneider, Bernard F.

    1999-01-01

    Purpose: Treatment of patients with occult carcinoma of the cervix discovered after simple hysterectomy is controversial. The purpose of this review is to examine our results with postoperative radiotherapy and to compare them to similar reports and to reports of treatment with radical parametrectomy. Methods and Materials: Between November 1979 and April:, 18 patients were treated with radiotherapy at the University of Virginia for invasive carcinoma of the cervix discovered after simple hysterectomy. Simple hysterectomy was performed in all 18 patients for a variety of indications. After surgery gross residual carcinoma remained in four patients; and microscopic disease was present at the surgical margins in two patients. The remaining patients had no evidence of residual disease. All 18 patients had postoperative radiotherapy with or without brachytherapy. The endpoints for this study were local control, survival, and treatment-related toxicity. Actuarial rates were calculated using the Life method. Results: Median follow-up for all 18 patients was 42 months (range 2-202 months). Both the 5 and the 10-year actuarial local control rates were 88%. Five and 10-year actuarial overall survival rates were both 93%. Two patients had both local and distant cancer recurrences. There were no recurrences among the six patients treated with external beam alone. The remaining patients are all alive without evidence of disease, including two patients who had gross residual disease after surgery, and one patient with both microscopic positive margin and a positive lymph node (the only patient to undergo lymph node sampling). There was no severe acute morbidity and only one patient had severe late morbidity. Conclusions: Invasive carcinoma found after simple hysterectomy may be treated safely and effectively with postoperative radiotherapy. Patients with known residual disease following surgery do poorly with either radiotherapy or reoperation, but treatment with radiotherapy

  14. [MRI findings and pathological features of occult breast cancer].

    Science.gov (United States)

    Zhang, J J; Yang, X T; Du, X S; Zhang, J X; Hou, L N; Niu, J L

    2018-01-23

    Objective: To investigate the magnetic resonance imaging (MRI) findings and clinicopathological features of primary lesions in patients with occult breast cancer (OBC). Methods: The imaging reports from the Breast Imaging Reporting and Data System in 2013 were retrospectively analyzed to investigate the morphology and the time signal intensity curve (TIC) of breast lesions in patients with OBC. The clinical and pathological characteristics of these patients were also included. Results: A total of 34 patients were enrolled. Among these patients, 24 patients underwent modified radical mastectomy and 18 of them had primary breast carcinoma in pathological sections. MRI detected 17 cases of primary lesions, including six masse lesions with a diameter of 0.6-1.2 cm (average 0.9 cm), and 11 non-mass lesions with four linear distributions, three segmental distributions, three focal distributions, and one regions distribution. Five patients had TIC typeⅠprimary lesions, ten had TIC type Ⅱ primary lesions, and two had TIC type Ⅲ primary lesions. Among all 34 cases, 23 of them had complete results of immunohistochemistry: 11 estrogen receptor (ER) positive lesions (47.8%), tenprogesterone receptor (PR) positive lesions (43.5%), seven human epidermal growth factor receptor 2 (HER-2) positive lesions (30.4%), and 20high expression(>14%) of Ki-67 (87.0%). The proportion of type luminal A was 4.3%, type luminal B was 43.5%, triple negative breast cancer (TNBC) was 30.4%, and HER-2 over expression accounted for 21.7%. Conclusions: The primary lesions of OBC usually manifested as small mass lesions, or focal, linear or segmental distribution of non-mass lesions. The positive rate of ER and PR was low, but the positive rate of HER-2 and the proliferation index of Ki-67 was high. Type luminal B is the most common molecular subtype.

  15. Waves in Saturn's rings probed by radio occultation

    International Nuclear Information System (INIS)

    Rosen, P.A.

    1989-01-01

    Thirty wave features, observed in 3.6 and 13 cm-wavelength optical depth profiles of Saturn's rings obtained by Voyager 1 radio occultation, are analyzed individually and comparatively. Many are the signature of spiral density waves and bending waves excited by gravitational resonances with Saturn's satellites. A new technique for locating waveform extrema, which fits a sinusoid to each half cycle of wave data, quantifies the wavelength variation across a feature. Fitting dispersion models to the derived wavelengths provides new estimates of ambient surface mass density σ in each wave region. For fourteen weak density waves in Ring A, modelling of the waveform near resonance with linear density wave theory gives independent estimates of σ, as well as reliable estimates of resonance location. Measurements of wave amplitude damping give an upper bound for ring thickness 2H, where H is the ring scale height. In the wave regions studied, Rings A, B, and C have 30 approx-lt σ approx-lt 70, σ approx-gt 65, and σ ∼ 1 g/cm 2 , respectively. Mass loading estimates from waveform modelling are 20 to 40% larger than dispersion-derived values, suggesting accumulation of mass in the wave regions. The average offset of derived wave location from theoretical resonance is about 1 km. Model waveforms of overlapping waves excited by the satellites Janus and Epimethenus agree well with observed morphologies in the linear region near resonance. In Ring C, dispersion analysis indicates that the most prominent wave feature, previously unidentified, is a one-armed spiral wave

  16. Occult HBV infection status among chronic hepatitis C and hemodialysis patients in Northeastern Egypt: regional and national overview.

    Science.gov (United States)

    Mandour, Mohamed; Nemr, Nader; Shehata, Atef; Kishk, Rania; Badran, Dahlia; Hawass, Nashaat

    2015-01-01

    Occult hepatitis B infection (OBI) is considered to be one of the major risks for patients suffering from end-stage renal disease (ESRD) on regular hemodialysis (HD) and patients with chronic hepatitis C virus (HCV) infection. This study compared the prevalence of OBI among these two high-risk groups in the Suez Canal region, Northeastern Egypt, to obtain a better national overview of the magnitude of OBI in this region. Serum samples were collected from 165 HD patients and 210 chronic HCV-infected patients. Anti-HCV antibody, hepatitis B surface antigen (HBsAg), total hepatitis B core (anti-HBc) antibody, and hepatitis B surface antibody (anti-HBs) were detected by enzyme-linked immunosorbent assay (ELISA). HCV RNA was detected using a quantitative real-time RT-PCR assay, and HBV was detected using a nested PCR. All patients were negative for HBsAg. A total of 49.1% and 25.2% of the patients in the HD and HCV groups, respectively, were anti-HBc-positive. In addition, more anti-HBs-positive patients were detected in the HD group compared to the HCV group (52.1% and 11.4%, respectively). Three cases were positive for HBV DNA in the HD group, while eighteen positive cases were detected in the HCV group. Both study groups showed significant differences in serum alanine aminotransferase (ALT) and aspartate aminotransferase (AST) level as well as anti-HBc, anti-HBs and HBV-DNA positivity. OBI was more prevalent among chronic HCV patients than HD patients in the Suez Canal region, Egypt, with rates of 8.5% and 1.8%, respectively. However, more precise assessment of this infection requires regular patient follow-up using HBV DNA detection methods.

  17. Lowest-order average effect of turbulence on atmospheric profiles derived from radio occultation

    International Nuclear Information System (INIS)

    Eshleman, V.R.; Haugstad, B.S.

    1977-01-01

    Turbulence in planetary atmospheres and ionospheres causes changes in angles of refraction of radio waves used in occultation experiments. Atmospheric temperature and pressure profiles, and ionospheric electron concentration profiles, derived from radio occultation measurements of Doppler frequency contain errors due to such angular offsets. The lowest-order average errors are derived from a geometrical-optics treatment of the radio-wave phase advance caused by the addition of uniform turbulence to an initially homogeneous medium. It is concluded that the average profile errors are small and that precise Doppler frequency measurements at two or more wavelengths could be used to help determine characteristics of the turbulence, as well as accuracy limits and possible correction terms for the profiles. However, a more detailed study of both frequency and intensity characteristics in radio and optical occultation measurements of turbulent planetary atmospheres and ionospheres is required to realize the full potential of such measurements

  18. An integration time adaptive control method for atmospheric composition detection of occultation

    Science.gov (United States)

    Ding, Lin; Hou, Shuai; Yu, Fei; Liu, Cheng; Li, Chao; Zhe, Lin

    2018-01-01

    When sun is used as the light source for atmospheric composition detection, it is necessary to image sun for accurate identification and stable tracking. In the course of 180 second of the occultation, the magnitude of sun light intensity through the atmosphere changes greatly. It is nearly 1100 times illumination change between the maximum atmospheric and the minimum atmospheric. And the process of light change is so severe that 2.9 times per second of light change can be reached. Therefore, it is difficult to control the integration time of sun image camera. In this paper, a novel adaptive integration time control method for occultation is presented. In this method, with the distribution of gray value in the image as the reference variable, and the concepts of speed integral PID control, the integration time adaptive control problem of high frequency imaging. The large dynamic range integration time automatic control in the occultation can be achieved.

  19. Magnetic field orientations in Saturn's upper ionosphere inferred from Voyager radio occultations

    Science.gov (United States)

    Hinson, D. P.

    1984-01-01

    The radio scintillations observed during occultations of Voyagers 1 and 2 by Saturn are analyzed to determine the morphology of plasma irregularities and hence the magnetic field orientation in Saturn's upper atmosphere. The measurement techniques, the weak scattering theory, and the method used to relate the observed radio scintillations to physical properties of the ionospheric irregularities are briefly described. Results on the spatial characteristics of the irregularities are presented, and the magnetic field orientation in Saturn's ionosphere is inferred. Although the occultation measurements generally confirm the accuracy of the Saturnian magnetic field model of Connerney et al. (1982), it is found that a small adjustment of the coefficients in that model's zonal harmonic expansion would remove the discrepancy between the model predictions and the measurements. A strategy for obtaining improved measurements of Saturn's magnetic field from radio occultation observations of scintillations and Faraday rotation using an orbiting spacecraft is briefly discussed.

  20. Do X-ray-occult fractures play a role in chronic pain following a whiplash injury?

    DEFF Research Database (Denmark)

    Hertzum-Larsen, Rasmus; Petersen, Henrik; Kasch, Helge

    2014-01-01

    symptoms following an MVA was invited to have a cervical SPECT shortly post injury and again 6 months later. Associations between occult fractures and pain levels at baseline, 6 and 12 months of follow-up were analyzed. Eighty-eight patients had baseline SPECT performed at median 15 days (range 3-28) post......Whiplash trauma in motor vehicle accidents (MVA) may involve various painful soft tissue damages, but weeks/months later a minority of victims still suffers from various long-lasting and disabling symptoms, whiplash-associated disorders (WAD). The etiology is currently unknown, but X......-ray-occult fractures may be one cause in some cases. The purpose of this prospective study was to examine the association between occult fractures, as seen on bone single photon emission computed tomography (SPECT), with neck-, head- and arm pain. An inception cohort of 107 patients presenting with acute whiplash...

  1. Solar Features - Solar Flares

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — A solar flare is a short-lived sudden increase in the intensity of radiation emitted in the neighborhood of sunspots. For many years it was best monitored in the...

  2. Double-layer model of the venus night-side ionosphere formation from the radio occultation data

    International Nuclear Information System (INIS)

    Osmolovskij, I.K.; Savich, N.A.; Samoznaev, L.N.

    1984-01-01

    The results of the radio occultation experiments performed with the Venera space probes - 9, 10(1975) and Pioneer - Venus satellite (1978) have shown that in most of the cases the electron concentration distribution in the Venus night-side ionosphere in the low solar activity years has two maxima (double-layer profile) whereas in the high activity years - one maximum. The two-component (O + and O 2 + ) diffusion model is suggested that describes naturally the formation of one or two maxima depending on physical conditions in the Venus upper atmosphere. At initial hypothesis accepted is the well-known hypothesis of the night-side ionosphere formation for account of the O + plasma overflow from the day side to the night one. The main idea of the study consists in finding conditions when the upper maximum formed in the O + ion downward current is spaced by height at a certain distance from the lower current caused by the O 2 + ions being formed as a result of O + ion chemical reactions with CO 2 molecules

  3. White Light Demonstration of One Hundred Parts per Billion Irradiance Suppression in Air by New Starshade Occulters

    Science.gov (United States)

    Levinton, Douglas B.; Cash, Webster C.; Gleason, Brian; Kaiser, Michael J.; Levine, Sara A.; Lo, Amy S.; Schindhelm, Eric; Shipley, Ann F.

    2007-01-01

    A new mission concept for the direct imaging of exo-solar planets called the New Worlds Observer (NWO) has been proposed. The concept involves flying a meter-class space telescope in formation with a newly-conceived, specially-shaped, deployable star-occulting shade several meters across at a separation of some tens of thousands of kilometers. The telescope would make its observations from behind the starshade in a volume of high suppression of incident irradiance from the star around which planets orbit. The required level of irradiance suppression created by the starshade for an efficacious mission is of order 0.1 to 10 parts per billion in broadband light. This paper discusses the experimental setup developed to accurately measure the suppression ratio of irradiance produced at the null position behind candidate starshade forms to these levels. It also presents results of broadband measurements which demonstrated suppression levels of just under 100 parts per billion in air using the Sun as a light source. Analytical modeling of spatial irradiance distributions surrounding the null are presented and compared with photographs of irradiance captured in situ behind candidate starshades.

  4. Occult Pelvic Lymph Node Involvement in Bladder Cancer: Implications for Definitive Radiation

    Energy Technology Data Exchange (ETDEWEB)

    Goldsmith, Benjamin; Baumann, Brian C.; He, Jiwei; Tucker, Kai; Bekelman, Justin; Deville, Curtiland; Vapiwala, Neha [Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania (United States); Vaughn, David; Keefe, Stephen M. [Department of Medical Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania (United States); Guzzo, Thomas; Malkowicz, S. Bruce [Department of Urology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania (United States); Christodouleas, John P., E-mail: christojo@uphs.upenn.edu [Department of Radiation Oncology, Hospital of the University of Pennsylvania, Philadelphia, Pennsylvania (United States)

    2014-03-01

    Purpose: To inform radiation treatment planning for clinically staged, node-negative bladder cancer patients by identifying clinical factors associated with the presence and location of occult pathologic pelvic lymph nodes. Methods and Materials: The records of patients with clinically staged T1-T4N0 urothelial carcinoma of the bladder undergoing radical cystectomy and pelvic lymphadenectomy at a single institution were reviewed. Logistic regression was used to evaluate associations between preoperative clinical variables and occult pathologic pelvic or common iliac lymph nodes. Percentages of patient with involved lymph node regions entirely encompassed within whole bladder (perivesicular nodal region), small pelvic (perivesicular, obturator, internal iliac, and external iliac nodal regions), and extended pelvic clinical target volume (CTV) (small pelvic CTV plus common iliac regions) were calculated. Results: Among 315 eligible patients, 81 (26%) were found to have involved pelvic lymph nodes at the time of surgery, with 38 (12%) having involved common iliac lymph nodes. Risk of occult pathologically involved lymph nodes did not vary with clinical T stage. On multivariate analysis, the presence of lymphovascular invasion (LVI) on preoperative biopsy was significantly associated with occult pelvic nodal involvement (odds ratio 3.740, 95% confidence interval 1.865-7.499, P<.001) and marginally associated with occult common iliac nodal involvement (odds ratio 2.307, 95% confidence interval 0.978-5.441, P=.056). The percentages of patients with involved lymph node regions entirely encompassed by whole bladder, small pelvic, and extended pelvic CTVs varied with clinical risk factors, ranging from 85.4%, 95.1%, and 100% in non-muscle-invasive patients to 44.7%, 71.1%, and 94.8% in patients with muscle-invasive disease and biopsy LVI. Conclusions: Occult pelvic lymph node rates are substantial for all clinical subgroups, especially patients with LVI on biopsy. Extended

  5. Solar storms; Tormentas solares

    Energy Technology Data Exchange (ETDEWEB)

    Collaboration: Pereira Cuesta, S.; Pereira Pagan, B.

    2016-08-01

    Solar storms begin with an explosion, or solar flare, on the surface of the sun. The X-rays and extreme ultraviolet radiation from the flare reach the Earths orbit minutes later-travelling at light speed. The ionization of upper layers of our atmosphere could cause radio blackouts and satellite navigation errors (GPS). Soon after, a wave of energetic particles, electrons and protons accelerated by the explosion crosses the orbit of the Earth, and can cause real and significant damage. (Author)

  6. Detection of an occult transclival cerebrospinal fluid fistula by CT and MRI

    Energy Technology Data Exchange (ETDEWEB)

    Schick, B.; Brors, D.; Draf, W. [Department of Ear, Nose and Throat Diseases, Head, Neck and Facial Plastic Surgery, Marburg Univ. (Germany); Goedecke, A. [Department of Radiology, Academic Teaching Hospital, Fulda (Germany); Prescher, A. [Department of Anatomy and Embryology, University Medical School, RWTH, Aachen (Germany)

    1998-12-01

    We describe an unusual occult transclival cerebrospinal fluid (CSF) fistula to the sphenoid sinus demonstrated by MRI. CT was performed because of a posterior cerebral infarct caused by cardiac arrhythmia. Axial sections showed fluid in the sphenoid sinus. High-resolution scans revealed a bony defect 3 mm in diameter of the posterior wall of the sphenoid sinus, and MRI showed a transclival CSF fistula. This occult lesion was confirmed by surgery and duraplasty was successfully performed via an endonasal approach. (orig.) With 3 figs., 19 refs.

  7. Occult Invasive Lobular Carcinoma of Breast Detected by Stomach Metastasis: A Case Report

    International Nuclear Information System (INIS)

    KIm, So Jung; Jung, Hae Kyoung; Ko, Kyung Hee; Yoon, Jung Hyun

    2012-01-01

    Gastric metastasis from primary breast cancer is a rare phenomenon that is more prevalent in the invasive lobular type of breast cancer. We describe a very rare case of occult invasive lobular cancer of the breast detected by the initial presentation of gastric metastasis in a patient without a history of breast cancer. A 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) which showed increased FDG uptake in the stomach, abdominal mesentery and the right breast, and played pivotal roles in the detection of occult primary breast cancer and a diagnosis of gastric metastasis as an ancillary method for obtaining histological results and immunohistochemical stains.

  8. Occult injuries of the femoral neck in osteoporosis of aged patients

    International Nuclear Information System (INIS)

    Reichelt, H.G.

    1985-01-01

    Fractures of the femoral neck in elderly patients are often a complication in osteoporosis. Diagnosis of fractures with displacement and compression of fragments is quite easy. The negative radiograph in old patients complaining of hip pain is generally considered a characteristic feature of presensile osteoporotic pain. Clinical examples present patients with hip pain caused by occult injuries of the femoral neck. They should be regarded as imminent fractures and adequately treated. Bone scan is very helpful in the early detection of such occult osteroporotic injuries. (orig.) [de

  9. Occult Invasive Lobular Carcinoma of Breast Detected by Stomach Metastasis: A Case Report

    Energy Technology Data Exchange (ETDEWEB)

    KIm, So Jung; Jung, Hae Kyoung; Ko, Kyung Hee; Yoon, Jung Hyun [Dept. of Radiology, Bundang CHA general Hospital, CHA University College of Medicine, Seongnam (Korea, Republic of)

    2012-02-15

    Gastric metastasis from primary breast cancer is a rare phenomenon that is more prevalent in the invasive lobular type of breast cancer. We describe a very rare case of occult invasive lobular cancer of the breast detected by the initial presentation of gastric metastasis in a patient without a history of breast cancer. A 18F-fluorodeoxyglucose positron-emission tomography/computed tomography (FDG PET/CT) which showed increased FDG uptake in the stomach, abdominal mesentery and the right breast, and played pivotal roles in the detection of occult primary breast cancer and a diagnosis of gastric metastasis as an ancillary method for obtaining histological results and immunohistochemical stains.

  10. Naturally occurring mutations in large surface genes related to occult infection of hepatitis B virus genotype C.

    Directory of Open Access Journals (Sweden)

    Hong Kim

    Full Text Available Molecular mechanisms related to occult hepatitis B virus (HBV infection, particularly those based on genotype C infection, have rarely been determined thus far in the ongoing efforts to determine infection mechanisms. Therefore, we aim to elucidate the mutation patterns in the surface open reading frame (S ORF underlying occult infections of HBV genotype C in the present study. Nested PCRs were applied to 624 HBV surface antigen (HBsAg negative Korean subjects. Cloning and sequencing of the S ORF gene was applied to 41 occult cases and 40 control chronic carriers. Forty-one (6.6% of the 624 Korean adults with HBsAg-negative serostatus were found to be positive for DNA according to nested PCR tests. Mutation frequencies in the three regions labeled here as preS1, preS2, and S were significantly higher in the occult subjects compared to the carriers in all cases. A total of two types of deletions, preS1 deletions in the start codon and preS2 deletions as well as nine types of point mutations were significantly implicated in the occult infection cases. Mutations within the "a" determinant region in HBsAg were found more frequently in the occult subjects than in the carriers. Mutations leading to premature termination of S ORF were found in 16 occult subjects (39.0% but only in one subject from among the carriers (2.5%. In conclusion, our data suggest that preS deletions, the premature termination of S ORF, and "a" determinant mutations are associated with occult infections of HBV genotype C among a HBsAg-negative population. The novel mutation patterns related to occult infection introduced in the present study can help to broaden our understanding of HBV occult infections.

  11. Adaptive regularization of noisy linear inverse problems

    DEFF Research Database (Denmark)

    Hansen, Lars Kai; Madsen, Kristoffer Hougaard; Lehn-Schiøler, Tue

    2006-01-01

    In the Bayesian modeling framework there is a close relation between regularization and the prior distribution over parameters. For prior distributions in the exponential family, we show that the optimal hyper-parameter, i.e., the optimal strength of regularization, satisfies a simple relation: T......: The expectation of the regularization function, i.e., takes the same value in the posterior and prior distribution. We present three examples: two simulations, and application in fMRI neuroimaging....

  12. Higher derivative regularization and chiral anomaly

    International Nuclear Information System (INIS)

    Nagahama, Yoshinori.

    1985-02-01

    A higher derivative regularization which automatically leads to the consistent chiral anomaly is analyzed in detail. It explicitly breaks all the local gauge symmetry but preserves global chiral symmetry and leads to the chirally symmetric consistent anomaly. This regularization thus clarifies the physics content contained in the consistent anomaly. We also briefly comment on the application of this higher derivative regularization to massless QED. (author)

  13. Regularity effect in prospective memory during aging

    Directory of Open Access Journals (Sweden)

    Geoffrey Blondelle

    2016-10-01

    Full Text Available Background: Regularity effect can affect performance in prospective memory (PM, but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults. Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30, 16 intermediate adults (40–55, and 25 older adults (65–80. The task, adapted from the Virtual Week, was designed to manipulate the regularity of the various activities of daily life that were to be recalled (regular repeated activities vs. irregular non-repeated activities. We examine the role of several cognitive functions including certain dimensions of executive functions (planning, inhibition, shifting, and binding, short-term memory, and retrospective episodic memory to identify those involved in PM, according to regularity and age. Results: A mixed-design ANOVA showed a main effect of task regularity and an interaction between age and regularity: an age-related difference in PM performances was found for irregular activities (older < young, but not for regular activities. All participants recalled more regular activities than irregular ones with no age effect. It appeared that recalling of regular activities only involved planning for both intermediate and older adults, while recalling of irregular ones were linked to planning, inhibition, short-term memory, binding, and retrospective episodic memory. Conclusion: Taken together, our data suggest that planning capacities seem to play a major role in remembering to perform intended actions with advancing age. Furthermore, the age-PM-paradox may be attenuated when the experimental design is adapted by implementing a familiar context through the use of activities of daily living. The clinical

  14. Regularity effect in prospective memory during aging

    OpenAIRE

    Blondelle, Geoffrey; Hainselin, Mathieu; Gounden, Yannick; Heurley, Laurent; Voisin, Hélène; Megalakaki, Olga; Bressous, Estelle; Quaglino, Véronique

    2016-01-01

    Background: Regularity effect can affect performance in prospective memory (PM), but little is known on the cognitive processes linked to this effect. Moreover, its impacts with regard to aging remain unknown. To our knowledge, this study is the first to examine regularity effect in PM in a lifespan perspective, with a sample of young, intermediate, and older adults.Objective and design: Our study examined the regularity effect in PM in three groups of participants: 28 young adults (18–30), 1...

  15. Models of Solar Irradiance Variations: Current Status Natalie A ...

    Indian Academy of Sciences (India)

    Abstract. Regular monitoring of solar irradiance has been carried out since 1978 to show that solar total and spectral irradiance varies at different time scales. Whereas variations on time scales of minutes to hours are due to solar oscillations and granulation, variations on longer time scales are driven by the evolution of the ...

  16. Regularization and error assignment to unfolded distributions

    CERN Document Server

    Zech, Gunter

    2011-01-01

    The commonly used approach to present unfolded data only in graphical formwith the diagonal error depending on the regularization strength is unsatisfac-tory. It does not permit the adjustment of parameters of theories, the exclusionof theories that are admitted by the observed data and does not allow the com-bination of data from different experiments. We propose fixing the regulariza-tion strength by a p-value criterion, indicating the experimental uncertaintiesindependent of the regularization and publishing the unfolded data in additionwithout regularization. These considerations are illustrated with three differentunfolding and smoothing approaches applied to a toy example.

  17. Iterative Regularization with Minimum-Residual Methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2007-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  18. Iterative regularization with minimum-residual methods

    DEFF Research Database (Denmark)

    Jensen, Toke Koldborg; Hansen, Per Christian

    2006-01-01

    subspaces. We provide a combination of theory and numerical examples, and our analysis confirms the experience that MINRES and MR-II can work as general regularization methods. We also demonstrate theoretically and experimentally that the same is not true, in general, for GMRES and RRGMRES - their success......We study the regularization properties of iterative minimum-residual methods applied to discrete ill-posed problems. In these methods, the projection onto the underlying Krylov subspace acts as a regularizer, and the emphasis of this work is on the role played by the basis vectors of these Krylov...... as regularization methods is highly problem dependent....

  19. Scaled-model guidelines for formation-flying solar coronagraph missions.

    Science.gov (United States)

    Landini, Federico; Romoli, Marco; Baccani, Cristian; Focardi, Mauro; Pancrazzi, Maurizio; Galano, Damien; Kirschner, Volker

    2016-02-15

    Stray light suppression is the main concern in designing a solar coronagraph. The main contribution to the stray light for an externally occulted space-borne solar coronagraph is the light diffracted by the occulter and scattered by the optics. It is mandatory to carefully evaluate the diffraction generated by an external occulter and the impact that it has on the stray light signal on the focal plane. The scientific need for observations to cover a large portion of the heliosphere with an inner field of view as close as possible to the photospheric limb supports the ambition of launching formation-flying giant solar coronagraphs. Their dimension prevents the possibility of replicating the flight geometry in a clean laboratory environment, and the strong need for a scaled model is thus envisaged. The problem of scaling a coronagraph has already been faced for exoplanets, for a single point source on axis at infinity. We face the problem here by adopting an original approach and by introducing the scaling of the solar disk as an extended source.

  20. Solar Energy.

    Science.gov (United States)

    Eaton, William W.

    Presented is the utilization of solar radiation as an energy resource principally for the production of electricity. Included are discussions of solar thermal conversion, photovoltic conversion, wind energy, and energy from ocean temperature differences. Future solar energy plans, the role of solar energy in plant and fossil fuel production, and…

  1. A regularized stationary mean-field game

    KAUST Repository

    Yang, Xianjin

    2016-01-01

    In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

  2. A regularized stationary mean-field game

    KAUST Repository

    Yang, Xianjin

    2016-04-19

    In the thesis, we discuss the existence and numerical approximations of solutions of a regularized mean-field game with a low-order regularization. In the first part, we prove a priori estimates and use the continuation method to obtain the existence of a solution with a positive density. Finally, we introduce the monotone flow method and solve the system numerically.

  3. On infinite regular and chiral maps

    OpenAIRE

    Arredondo, John A.; Valdez, Camilo Ramírez y Ferrán

    2015-01-01

    We prove that infinite regular and chiral maps take place on surfaces with at most one end. Moreover, we prove that an infinite regular or chiral map on an orientable surface with genus can only be realized on the Loch Ness monster, that is, the topological surface of infinite genus with one end.

  4. From recreational to regular drug use

    DEFF Research Database (Denmark)

    Järvinen, Margaretha; Ravn, Signe

    2011-01-01

    This article analyses the process of going from recreational use to regular and problematic use of illegal drugs. We present a model containing six career contingencies relevant for young people’s progress from recreational to regular drug use: the closing of social networks, changes in forms...

  5. Automating InDesign with Regular Expressions

    CERN Document Server

    Kahrel, Peter

    2006-01-01

    If you need to make automated changes to InDesign documents beyond what basic search and replace can handle, you need regular expressions, and a bit of scripting to make them work. This Short Cut explains both how to write regular expressions, so you can find and replace the right things, and how to use them in InDesign specifically.

  6. Regularization modeling for large-eddy simulation

    NARCIS (Netherlands)

    Geurts, Bernardus J.; Holm, D.D.

    2003-01-01

    A new modeling approach for large-eddy simulation (LES) is obtained by combining a "regularization principle" with an explicit filter and its inversion. This regularization approach allows a systematic derivation of the implied subgrid model, which resolves the closure problem. The central role of

  7. 29 CFR 779.18 - Regular rate.

    Science.gov (United States)

    2010-07-01

    ... employee under subsection (a) or in excess of the employee's normal working hours or regular working hours... Relating to Labor (Continued) WAGE AND HOUR DIVISION, DEPARTMENT OF LABOR STATEMENTS OF GENERAL POLICY OR... not less than one and one-half times their regular rates of pay. Section 7(e) of the Act defines...

  8. Treatment for occult hepatocellular carcinoma: does it offer survival advantages over symptom-driven treatment?

    Science.gov (United States)

    Kim, Kwang Min; Kim, Jiyu; Sinn, Dong Hyun; Kim, Hye Seung; Kim, Kyunga; Kang, Wonseok; Gwak, Geum-Youn; Paik, Yong-Han; Choi, Moon Seok; Lee, Joon Hyeok; Koh, Kwang Cheol; Paik, Seung Woon

    2018-04-03

    In order to claim a benefit of screen-based diagnosis for asymptomatic individuals, treatment of occult disease needs to offer survival advantages compared to the treatment of symptomatic disease, yet information on this issue is scarce with regard to hepatocellular carcinoma (HCC) screening. A total of 3353 treatment-naïve, consecutive, newly diagnosed HCC patients [age: 57.9 ± 10.3, male: 2,689 (80.2%), hepatitis B virus: 2555 (76.2%)], diagnosed between 2010 and 2013 were analyzed. Data on the mode of detection was prospectively collected at the time of HCC diagnosis and was used to group patients into occult or symptomatic cases. Overall, 643 (19.2%) patients were symptomatic cases. The proportion of patients undergoing resection, radiofrequency ablation or transplantation were lower in symptomatic cases than occult cases (20.8 vs. 56.2%, p offered a survival benefit to patients over symptomatic cases. These data support screening practices for asymptomatic individuals to diagnose occult HCC.

  9. Endoscopic Follow-Up of Positive Fecal Occult Blood Testing in the Ontario FOBT Project

    Directory of Open Access Journals (Sweden)

    Lawrence Paszat

    2007-01-01

    Full Text Available BACKGROUND: The Ontario FOBT Project is a pilot study of fecal occult blood testing (FOBT for colorectal cancer screening conducted among age-eligible volunteers (50 to 75 years in 12 of 37 public health regions in Ontario.

  10. Occult hepatitis B virus among the patients with abnormal alanine transaminase.

    Science.gov (United States)

    Makvandi, Manoochehr; Neisi, Niloofar; Khalafkhany, Davod; Makvandi, Kamyar; Hajiani, Eskandar; Shayesteh, Ali Akbar; Masjedi Zadeh, Abdolrahim; Sina, Amir Hosein; Hamidifard, Mojtaba; Rasti, Mojtaba; Aryan, Ehsan; Ahmadi, Kambiz; Yad Yad, Mohammad Jafar

    2014-08-01

    The occult hepatitis B infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in the sera or in the liver biopsy and the absence of hepatitis B surface antigen (HBsAg) by serological test. The current study aimed to evaluate the occult HBV infection by polymerase chain reaction (PCR) and determine HBV genotyping among the patients with abnormal alanine transaminase (ALT) in Ahvaz city, Iran. The sera of 120 patients, 54 (45%) females and 66 (55%) males, with abnormal ALT 40-152 IU were collected. All the patients were negative for HBsAg for more than one year. The patients` sera were tested by PCR using primers specified for the S region of HBV. Then the positive PCR products were sequenced to determine HBV genotyping and phylogenic tree. Of these 120 subjects, 12 (10%) patients including 6 (5%) males and 6 (5%) females were found positive for HBV DNA by PCR, which indicated the presence of occult HBV infection among these patients. The sequencing results revealed that genotype D was predominant with sub-genotyping D1 among OBI patients. Occult hepatitis B infection is remarkably prevalent in Ahvaz, Iran, and should be considered as a potential risk factor for the transmission of Hepatitis B Virus throughout the community by the carriers.

  11. Lunar occultation of the Galactic center at 2.2 microns

    NARCIS (Netherlands)

    Adams, D. J.; Becklin, E. E.; Jameson, R. F.; Longmore, A. J.; Sandqvist, Aa.; Valentijn, E.

    1988-01-01

    Results of the lunar occultation of IRS 16 on 1986 September 11 are reported. Sixty percent of the observed flux in a 6arcsec.5 beam comes from four discrete sources. Three sources are unresolved pointlike objects (<0arcsec.05) and are assumed to be individual stars. The fourth object is well

  12. Occult Hepatitis B Virus Among the Patients With Abnormal Alanine Transaminase

    Science.gov (United States)

    Makvandi, Manoochehr; Neisi, Niloofar; Khalafkhany, Davod; Makvandi, Kamyar; Hajiani, Eskandar; Shayesteh, Ali Akbar; Masjedi Zadeh, Abdolrahim; Sina, Amir Hosein; Hamidifard, Mojtaba; Rasti, Mojtaba; Aryan, Ehsan; Ahmadi, Kambiz; Yad Yad, Mohammad Jafar

    2014-01-01

    Background: The occult hepatitis B infection (OBI) is defined as the presence of hepatitis B virus (HBV) DNA in the sera or in the liver biopsy and the absence of hepatitis B surface antigen (HBsAg) by serological test. Objectives: The current study aimed to evaluate the occult HBV infection by polymerase chain reaction (PCR) and determine HBV genotyping among the patients with abnormal alanine transaminase (ALT) in Ahvaz city, Iran. Patients and Methods: The sera of 120 patients, 54 (45%) females and 66 (55%) males, with abnormal ALT 40-152 IU were collected. All the patients were negative for HBsAg for more than one year. The patients` sera were tested by PCR using primers specified for the S region of HBV. Then the positive PCR products were sequenced to determine HBV genotyping and phylogenic tree. Results: Of these 120 subjects, 12 (10%) patients including 6 (5%) males and 6 (5%) females were found positive for HBV DNA by PCR, which indicated the presence of occult HBV infection among these patients. The sequencing results revealed that genotype D was predominant with sub-genotyping D1 among OBI patients. Conclusions: Occult hepatitis B infection is remarkably prevalent in Ahvaz, Iran, and should be considered as a potential risk factor for the transmission of Hepatitis B Virus throughout the community by the carriers. PMID:25485052

  13. Post traumatic urinary extravasation in occult urinary obstruction: Report of three cases

    Directory of Open Access Journals (Sweden)

    Jyoti Bothra

    2016-01-01

    Full Text Available Urinary extravastion after blunt abdominal trauma is seen often and generally treated conservatively. However a blunt renal trauma causing huge amount of extravasations and symptoms disproportionate to the severity of trauma should alarm the surgeon towards an underlying occult renal pathology usually an obstruction. In this case series, we share three such experiences and their management.

  14. Detection of occult hepatitis B virus among chronic hepatitis C patients

    African Journals Online (AJOL)

    Background: Concurrent infections with hepatitis B virus (HBV) and hepatitis C virus (HCV) are increasingly recognized in patients with chronic hepatitis. In Egypt, the last decade showed a remarkable decline in HBV infection associated with remarkable rise in HCV infection. The probable impact of occult HBV in patients ...

  15. Earlier stages of colorectal cancer detected with immunochemical faecal occult blood tests

    NARCIS (Netherlands)

    van Rossum, L. G. M.; van Rijn, A. F.; van Munster, I. P.; Jansen, J. B. M. J.; Fockens, P.; Laheij, R. J. F.; Dekker, E.

    2009-01-01

    Background: The aim of colorectal cancer screening is to improve prognosis by the detection of early cancer and precursor stages. We compared the stage distribution of asymptomatic colorectal cancer patients detected by a positive immunochemical or guaiac-based faecal occult blood test (FOBT) with

  16. Aplastic crisis in occult hereditary spherocytosis caused by human parvovirus (HPV B19).

    Science.gov (United States)

    Rappaport, E S; Quick, G; Ransom, D; Helbert, B; Frankel, L S

    1989-02-01

    We have reported a case of aplastic crisis occurring in an 11-year-old black boy with occult hereditary spherocytosis. An etiologic diagnosis of human parvovirus (HPV) B19 infection was confirmed serologically. The Coulter Model S + IV proved useful for both diagnosis and treatment monitoring through serial histograms. The relationship of HPV infection and aplastic crisis is discussed.

  17. Clinical relevance of occult tumor cells in lymph nodes from gastric cancer patients.

    NARCIS (Netherlands)

    Doekhie, F.S.; Mesker, W.H.; Krieken, J.H.J.M. van; Kok, N.F.; Hartgrink, H.H.; Kranenbarg, E.K.; Putter, H.; Kuppen, P.J.; Tanke, H.J.; Tollenaar, R.A.E.M.; Velde, C.J. van de

    2005-01-01

    The current method for staging in gastric cancer is not sufficient as even after a complete primary tumor resection, patients with node-negative gastric cancer suffer from disease recurrence. In this study, the relation between disease recurrence and the presence of occult tumor cells (OTC) in lymph

  18. Design and Verification of External Occulters for Direct Imaging of Extrasolar Planets

    Science.gov (United States)

    Cady, Eric

    2011-01-01

    An occulter is an optical element which is placed in front of the telescope to block most of the light from a star before it reaches the optics inside, without blocking the planet.In our case, we use two spacecraft ying in formation: First has its edge shaped to cancel the starlight Second is the telescope which images the star and planet

  19. Inappropriate use of the faecal occult blood test in a university hospital in the Netherlands

    NARCIS (Netherlands)

    van Rijn, Anne F.; Stroobants, An K.; Deutekom, Marije; Lauppe, Corinne; Sturk, Auguste; Bossuyt, Patrick M. M.; Fockens, Paul; Dekker, Evelien

    2012-01-01

    Objectives Although all international guidelines state that there is no indication to perform a faecal occult blood test (FOBT) in symptomatic patients, we believe the test is frequently used as a diagnostic test. The objective of this study was to investigate whether the current guidelines for FOBT

  20. Tropical cyclone cloud‐top height and vertical temperature structure detection using GPS radio occultation measurements

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Ho, Shu‐Peng; Randel, William

    2013-01-01

    The accurate determination of tropical cyclone (TC) cloud-top height and its vertical thermal structure using the GPS radio occultation (RO) technique is demonstrated in this study. Cloud-top heights are determined by using the bending angle anomaly and the temperature anomaly profiles during...

  1. Indeling occulte tumorcellen in de lymfklieren bij patiënten met darmkanker onvoldoende betrouwbaar

    NARCIS (Netherlands)

    van der Zaag, E. S.; Welling, L.; Peters, H. M.; van de Vijver, M. J.; Bemelman, W. A.; Buskens, C. J.

    2011-01-01

    OBJECTIVE: To assess interobserver agreement between pathologists in judging photographs of lymph node preparations of occult tumour cells of patients with colon cancer. DESIGN: Descriptive and comparative study of interobserver variability. METHODS: All lymph nodes of 82 pN0 patients with colon

  2. GPS radio occultation technique for measurement of the atmosphere above tropical cyclones

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Neubert, Torsten; Syndergaard, Stig

    2009-01-01

    Water vapour transport to the upper troposphere (UT) and lower stratosphere (LS) by deep convective storms affects the radiation balance of the atmosphere and has been proposed as an important component of climate change. The aim of the work presented here is to understand if the GPS Radio Occult...... 2008 and reached a maximum intensity of Category 3....

  3. Solar energy

    Science.gov (United States)

    Rapp, D.

    1981-01-01

    The book opens with a review of the patterns of energy use and resources in the United States, and an exploration of the potential of solar energy to supply some of this energy in the future. This is followed by background material on solar geometry, solar intensities, flat plate collectors, and economics. Detailed attention is then given to a variety of solar units and systems, including domestic hot water systems, space heating systems, solar-assisted heat pumps, intermediate temperature collectors, space heating/cooling systems, concentrating collectors for high temperatures, storage systems, and solar total energy systems. Finally, rights to solar access are discussed.

  4. Solar Combisystems

    DEFF Research Database (Denmark)

    Thür, Alexander

    2006-01-01

    This note first introduces what is a solar combisystem, the structure how a solar combisystem is build up and what are criteria’s to evaluate a solar combisystem concept. Further on the main components of a solar combisystem, the main characteristics and possible advantages and disadvantages...... compared to each other are described. It is not the goal of this note to explain the technical details how to design all components of a solar combisystem. This is done during other lectures of the solar course and in other basic courses as well. This note tries to explain how a solar combisystem...

  5. Solar Systems

    Science.gov (United States)

    1979-01-01

    The solar collectors shown are elements of domestic solar hot water systems produced by Solar One Ltd., Virginia Beach, Virginia. Design of these systems benefited from technical expertise provided Solar One by NASA's Langley Research Center. The company obtained a NASA technical support package describing the d e sign and operation of solar heating equipment in NASA's Tech House, a demonstration project in which aerospace and commercial building technology are combined in an energy- efficient home. Solar One received further assistance through personal contact with Langley solar experts. The company reports that the technical information provided by NASA influenced Solar One's panel design, its selection of a long-life panel coating which increases solar collection efficiency, and the method adopted for protecting solar collectors from freezing conditions.

  6. Estimation and evaluation of COSMIC radio occultation excess phase using undifferenced measurements

    Science.gov (United States)

    Xia, Pengfei; Ye, Shirong; Jiang, Kecai; Chen, Dezhong

    2017-05-01

    In the GPS radio occultation technique, the atmospheric excess phase (AEP) can be used to derive the refractivity, which is an important quantity in numerical weather prediction. The AEP is conventionally estimated based on GPS double-difference or single-difference techniques. These two techniques, however, rely on the reference data in the data processing, increasing the complexity of computation. In this study, an undifferenced (ND) processing strategy is proposed to estimate the AEP. To begin with, we use PANDA (Positioning and Navigation Data Analyst) software to perform the precise orbit determination (POD) for the purpose of acquiring the position and velocity of the mass centre of the COSMIC (The Constellation Observing System for Meteorology, Ionosphere and Climate) satellites and the corresponding receiver clock offset. The bending angles, refractivity and dry temperature profiles are derived from the estimated AEP using Radio Occultation Processing Package (ROPP) software. The ND method is validated by the COSMIC products in typical rising and setting occultation events. Results indicate that rms (root mean square) errors of relative refractivity differences between undifferenced and atmospheric profiles (atmPrf) provided by UCAR/CDAAC (University Corporation for Atmospheric Research/COSMIC Data Analysis and Archive Centre) are better than 4 and 3 % in rising and setting occultation events respectively. In addition, we also compare the relative refractivity bias between ND-derived methods and atmPrf profiles of globally distributed 200 COSMIC occultation events on 12 December 2013. The statistical results indicate that the average rms relative refractivity deviation between ND-derived and COSMIC profiles is better than 2 % in the rising occultation event and better than 1.7 % in the setting occultation event. Moreover, the observed COSMIC refractivity profiles from ND processing strategy are further validated using European Centre for Medium

  7. Sizes of the Smallest Particles at Saturn Ring Edges from Diffraction in UVIS Stellar Occultations

    Science.gov (United States)

    Eckert, S.; Colwell, J. E.; Becker, T. M.; Esposito, L. W.

    2017-12-01

    Cassini's Ultraviolet Imaging Spectrograph (UVIS) has observed more than 150 ring stellar occultations since its arrival at Saturn in 2004. We use stellar occultation data from the UVIS High Speed Photometer (HSP) to identify diffraction signals at ring edges caused by small particles diffracting light into the detector and consequently increasing the signal above that of the unocculted star. The shape of a diffraction signal is indicative of the particle size distribution at the ring edge, which may be a dynamically perturbed region. Becker et al. (2015 Icarus doi:10.1016/j.icarus.2015.11.001) analyzed diffraction signals at the outer edge of the A Ring and the edges of the Encke Gap. We apply the Becker et al. (2015) model to the outer edge of the B Ring as well as the edges of ringlets within the C Ring and Cassini Division. In addition, we analyze diffraction signatures at the A Ring outer edge in 2 new occultations. The best-fit model signals to these occultations are consistent with the findings of Becker et al. (2015) who found an average minimum particle size amin =4.5 mm and average power law slope q=3.2. At the B Ring outer edge, we detect a diffraction signal in 10 of 28 occultations in which the diffraction signal would be observable according to our criteria for star brightness and observation geometry. We find a mean amin =11 mm and a mean q=3.0. At both edges of the so-called "Strange" ringlet (R6) we find a mean amin = 20 mm and mean q values of 3.0 and 2.8 at the inner and outer edges, respectively. In contrast, we do not observe any clear diffraction signals at either edge of the wider Huygens ringlet. This could imply an absence of cm-scale or smaller particles and indicates that collisions here may be less vigorous than at the other ring edges analyzed in this study. We detect diffraction in a small fraction ( 10%) of occultations at 3 ringlets within the Cassini Division: the Herschel ringlet, the Laplace ringlet, and the Barnard ringlet. We

  8. Partially Transparent Petaled Mask/Occulter for Visible-Range Spectrum

    Science.gov (United States)

    Shiri, Ron Shahram; Wasylkiwskyj, Wasyl

    2013-01-01

    The presence of the Poisson Spot, also known as the spot of Arago, has been known since the 18th century. This spot is the consequence of constructive interference of light diffracted by the edge of the obstacle where the central position can be determined by symmetry of the object. More recently, many NASA missions require the suppression of this spot in the visible range. For instance, the exoplanetary missions involving space telescopes require telescopes to image the planetary bodies orbiting central stars. For this purpose, the starlight needs to be suppressed by several orders of magnitude in order to image the reflected light from the orbiting planet. For the Earth-like planets, this suppression needs to be at least ten orders of magnitude. One of the common methods of suppression involves sharp binary petaled occulters envisioned to be placed many thousands of miles away from the telescope blocking the starlight. The suppression of the Poisson Spot by binary sharp petal tips can be problematic when the thickness of the tips becomes smaller than the wavelength of the incident beam. First they are difficult to manufacture and also it invalidates the laws of physical optics. The proposed partially transparent petaled masks/occulters compensate for this sharpness with transparency along the surface of the petals. Depending on the geometry of the problem, this transparency can be customized such that only a small region of the petal is transparent and the remaining of the surface is opaque. This feature allows easy fabrication of this type of occultation device either as a mask or occulter. A partially transparent petaled mask/ occulter has been designed for the visible spectrum range. The mask/occulter can suppress the intensity along the optical axis up to ten orders of magnitude. The design process can tailor the mask shape, number of petals, and transparency level to the near-field and farfield diffraction region. The mask/occulter can be used in space

  9. Histopathological Parameters predicting Occult Nodal Metastases in Tongue Carcinoma Cases: An Indian Perspective.

    Science.gov (United States)

    Jacob, Tina Elizabeth; Malathi, N; Rajan, Sharada T; Augustine, Dominic; Manish, N; Patil, Shankargouda

    2016-01-01

    It is a well-established fact that in squamous cell carcinoma cases, the presence of lymph node metastases decreased the 5-year survival rate by 50% and also caused the recurrence of the primary tumor with development of distant metastases. Till date, the predictive factors for occult cervical lymph nodes metastases in cases of tongue squamous cell carcinoma remain inconclusive. Therefore, it is imperative to identify patients who are at the greatest risk for occult cervical metastases. This study was thus performed with the aim to identify various histopathologic parameters of the primary tumor that predict occult nodal metastases. The clinicopathologic features of 56 cases of lateral tongue squamous cell carcinoma with cT1NoMo/cT2NoMo as the stage and without prior radiotherapy or chemotherapy were considered. The surgical excision of primary tumor was followed by elective neck dissection. The glossectomy specimen along with the neck nodes were fixed in formalin and 5 urn thick sections were obtained. The hematoxylin & eosin stained sections were then subjected to microscopic examination. The primary tumor characteristics that were analyzed include tumor grade, invading front, depth of tumor, lymphovascular invasion, perineural invasion and inflammatory response. The nodes were examined for possible metastases using hematoxylin & eosin followed by cytokeratin immunohistochemistry. A total of 12 cases were found with positive occult nodal metastases. On performing univariate analysis, the histopathologic parameters that were found to be statistically significant were lymphovascular invasion (p = 0.004) and perineural invasion (p = 0.003) along with a cut-off depth of infiltration more than 5 mm (p = 0.01). Histopathologic assessment of the primary tumor specimen therefore continues to provide information that is central to guide clinical management, particularly in cases of occult nodal metastases. Clinical significance The study highlights the importance of

  10. Solar radiophysics

    International Nuclear Information System (INIS)

    McLean, D.J.; Labrum, N.R.

    1985-01-01

    This book treats all aspects of solar radioastronomy at metre wavelengths, particularly work carried out on the Australian radioheliograph at Culgoora, with which most of the authors have been associated in one way or another. After an introductory section on historical aspects, the solar atmosphere, solar flares, and coronal radio emission, the book deals with instrumentation, theory, and details of observations and interpretations of the various aspects of metrewave solar radioastronomy, including burst types, solar storms, and the quiet sun. (U.K.)

  11. Occult pneumothorax in trauma patients: should this be sought in the focused assessment with sonography for trauma examination?

    Science.gov (United States)

    Tam, Michael M K

    2005-01-01

    At present, CT scan is the gold standard for detecting occult traumatic pneumothorax not apparent on supine chest X-ray radiograph. Recently there were suggestions to expand focused assessment with sonography for trauma (FAST) to include thoracic ultrasound for detecting pneumothorax. The aim of the present study is to determine the incidence of occult pneumothorax (as shown by CT) in the subgroup of trauma patients undergoing FAST. Review of all trauma patients with FAST done from 1 June 2001 to 31 October 2002. Incidence of occult pneumothorax as diagnosed by CT was determined. Patients were not counted as having true occult pneumothorax if they had chest drains inserted before arrival or imaging studies. Selected clinical findings were tested for association with occult pneumothorax. In total, 143 patients underwent FAST, of whom 137 (95.8%) had chest X-ray examination performed. Of the 137 patients 59 required CT abdomen and/or thorax. Occult pneumothorax was found in three patients (2.1%). A history of thorax and/or abdominal injury plus one or more of: (i) mechanisms potentially causing major trauma; (ii) abnormal chest examination; and (iii) chest X-ray radiograph abnormality in the absence of pneumothorax, was significantly associated with the presence of occult pneumothorax (P = 0.03, Fisher's exact test; sensitivity: 100%; specificity: 71%; likelihood ratio: 3.42). The incidence of occult pneumothorax in the subgroup of trauma patients undergoing FAST is low. It implies that routine screening for its presence by adding thoracic ultrasound to FAST is unnecessary. Identifying those at risk of occult pneumothorax for further investigation appeared feasible.

  12. Stellar Occultations by TNOs and Centaurs: first results in the “Gaia era”

    Science.gov (United States)

    Rossi, Gustavo; Vieira-Martins, Roberto; Sicardy, Bruno; Ortiz, Jose Luis; Rio Group, Lucky Star Occultation Team, Granada Occultation Team

    2017-10-01

    After the first release of the GAIA catalog (in September/2016), stellar positions are now known with unprecedented accuracy, reaching values of the order of milliarcseconds. This improvement reflected into a stunning accuracy on the astrometry of moving objects, such as TNOs. Unfortunately, Gaia stars proper motions will be only available on the second data release (DR2) next year, so there is still a need to use hybrid stellar catalogs for occultation predictions until then. Despite that, stellar occultations predictions are now much more accurate, and the biggest uncertainties comes mainly from the object ephemerides. This issue will be overcome by large surveys such as the LSST, which will provide positions for the known TNOs and it is expected to increase the number of known TNOs by nearly 40,000, with an unprecedent amount of acquired information.This huge amount of data also poses a new era in stellar occultations: predictions will be very accurate and the participation of professional astronomers, laboratories, and the amateur community will be crucial to observe the predicted events; observation campaigns will need to be selected according to a specific scientific purpose such as the probability to detect rings or archs around a body, the presence of atmosphere or even the detection of topographic features; the development of softwares capable of reducing the data more efficiently and an easier method to coordinate observation campaigns are needed.Here we present some impressive results obtained from predictions and observed occultations in 2017 (among them we have Pluto, Chariklo and Haumea), the problems we are starting to face in the beginning of the “Gaia era” and the future challenges of stellar occultation.

  13. Predictive factors of occult neck metastasis in patients with oral squamous cell carcinoma

    Directory of Open Access Journals (Sweden)

    Renato Fortes Bittar

    Full Text Available ABSTRACT INTRODUCTION: It is well established that cervical lymph node metastasis is the most important prognostic factor in patients with oral squamous cell carcinoma of the upper aerodigestive tract. The definition of parameters and classifications that could separate patients in groups of low, intermediate and high-risk is being attempted for several years. OBJECTIVE: The objective of this study was to determine possible predictive factors related to the occurrence of occult cervical lymph node metastasis through the analysis of histopathological reports of surgical specimens obtained after oral squamous cell carcinoma resection and selective neck dissections of patients initially classified as N0. METHODS: This was a primary, retrospective, observational, case-control study. Histopathological reports were reviewed to determine if some findings were related to the occurrence of occult lymph node metastasis. The events analyzed were oral cavity subsites, pT-stage, muscular infiltration, desmoplasia, vascular emboli, perineural infiltration, tumor thickness and compromised margins. RESULTS: Occult cervical metastasis accounted for 19.10 percent of the cases. Desmoplasia, perineural infiltration, tumor thickness and pT4a stage are predictive factors of occult neck metastasis (p-value = 0.0488, 0.0326, 0.0395, 0.0488, respectively. CONCLUSION: The accurate definition of predictive factors of occult cervical metastasis may guide the selection of patients that should be referred to radiotherapy, avoiding the unnecessary exposure of low-risk patients to radiation and allowing a better regional control of the disease in those of moderate or high risk.

  14. An iterative method for Tikhonov regularization with a general linear regularization operator

    NARCIS (Netherlands)

    Hochstenbach, M.E.; Reichel, L.

    2010-01-01

    Tikhonov regularization is one of the most popular approaches to solve discrete ill-posed problems with error-contaminated data. A regularization operator and a suitable value of a regularization parameter have to be chosen. This paper describes an iterative method, based on Golub-Kahan

  15. Multiple graph regularized protein domain ranking

    KAUST Repository

    Wang, Jim Jing-Yan

    2012-11-19

    Background: Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods.Results: To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods.Conclusion: The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications. 2012 Wang et al; licensee BioMed Central Ltd.

  16. Multiple graph regularized protein domain ranking

    KAUST Repository

    Wang, Jim Jing-Yan; Bensmail, Halima; Gao, Xin

    2012-01-01

    Background: Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods.Results: To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods.Conclusion: The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications. 2012 Wang et al; licensee BioMed Central Ltd.

  17. Hierarchical regular small-world networks

    International Nuclear Information System (INIS)

    Boettcher, Stefan; Goncalves, Bruno; Guclu, Hasan

    2008-01-01

    Two new networks are introduced that resemble small-world properties. These networks are recursively constructed but retain a fixed, regular degree. They possess a unique one-dimensional lattice backbone overlaid by a hierarchical sequence of long-distance links, mixing real-space and small-world features. Both networks, one 3-regular and the other 4-regular, lead to distinct behaviors, as revealed by renormalization group studies. The 3-regular network is planar, has a diameter growing as √N with system size N, and leads to super-diffusion with an exact, anomalous exponent d w = 1.306..., but possesses only a trivial fixed point T c = 0 for the Ising ferromagnet. In turn, the 4-regular network is non-planar, has a diameter growing as ∼2 √(log 2 N 2 ) , exhibits 'ballistic' diffusion (d w = 1), and a non-trivial ferromagnetic transition, T c > 0. It suggests that the 3-regular network is still quite 'geometric', while the 4-regular network qualifies as a true small world with mean-field properties. As an engineering application we discuss synchronization of processors on these networks. (fast track communication)

  18. Multiple graph regularized protein domain ranking.

    Science.gov (United States)

    Wang, Jim Jing-Yan; Bensmail, Halima; Gao, Xin

    2012-11-19

    Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods. To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods. The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications.

  19. Coupling regularizes individual units in noisy populations

    International Nuclear Information System (INIS)

    Ly Cheng; Ermentrout, G. Bard

    2010-01-01

    The regularity of a noisy system can modulate in various ways. It is well known that coupling in a population can lower the variability of the entire network; the collective activity is more regular. Here, we show that diffusive (reciprocal) coupling of two simple Ornstein-Uhlenbeck (O-U) processes can regularize the individual, even when it is coupled to a noisier process. In cellular networks, the regularity of individual cells is important when a select few play a significant role. The regularizing effect of coupling surprisingly applies also to general nonlinear noisy oscillators. However, unlike with the O-U process, coupling-induced regularity is robust to different kinds of coupling. With two coupled noisy oscillators, we derive an asymptotic formula assuming weak noise and coupling for the variance of the period (i.e., spike times) that accurately captures this effect. Moreover, we find that reciprocal coupling can regularize the individual period of higher dimensional oscillators such as the Morris-Lecar and Brusselator models, even when coupled to noisier oscillators. Coupling can have a counterintuitive and beneficial effect on noisy systems. These results have implications for the role of connectivity with noisy oscillators and the modulation of variability of individual oscillators.

  20. Multiple graph regularized protein domain ranking

    Directory of Open Access Journals (Sweden)

    Wang Jim

    2012-11-01

    Full Text Available Abstract Background Protein domain ranking is a fundamental task in structural biology. Most protein domain ranking methods rely on the pairwise comparison of protein domains while neglecting the global manifold structure of the protein domain database. Recently, graph regularized ranking that exploits the global structure of the graph defined by the pairwise similarities has been proposed. However, the existing graph regularized ranking methods are very sensitive to the choice of the graph model and parameters, and this remains a difficult problem for most of the protein domain ranking methods. Results To tackle this problem, we have developed the Multiple Graph regularized Ranking algorithm, MultiG-Rank. Instead of using a single graph to regularize the ranking scores, MultiG-Rank approximates the intrinsic manifold of protein domain distribution by combining multiple initial graphs for the regularization. Graph weights are learned with ranking scores jointly and automatically, by alternately minimizing an objective function in an iterative algorithm. Experimental results on a subset of the ASTRAL SCOP protein domain database demonstrate that MultiG-Rank achieves a better ranking performance than single graph regularized ranking methods and pairwise similarity based ranking methods. Conclusion The problem of graph model and parameter selection in graph regularized protein domain ranking can be solved effectively by combining multiple graphs. This aspect of generalization introduces a new frontier in applying multiple graphs to solving protein domain ranking applications.

  1. Diagrammatic methods in phase-space regularization

    International Nuclear Information System (INIS)

    Bern, Z.; Halpern, M.B.; California Univ., Berkeley

    1987-11-01

    Using the scalar prototype and gauge theory as the simplest possible examples, diagrammatic methods are developed for the recently proposed phase-space form of continuum regularization. A number of one-loop and all-order applications are given, including general diagrammatic discussions of the nogrowth theorem and the uniqueness of the phase-space stochastic calculus. The approach also generates an alternate derivation of the equivalence of the large-β phase-space regularization to the more conventional coordinate-space regularization. (orig.)

  2. J-regular rings with injectivities

    OpenAIRE

    Shen, Liang

    2010-01-01

    A ring $R$ is called a J-regular ring if R/J(R) is von Neumann regular, where J(R) is the Jacobson radical of R. It is proved that if R is J-regular, then (i) R is right n-injective if and only if every homomorphism from an $n$-generated small right ideal of $R$ to $R_{R}$ can be extended to one from $R_{R}$ to $R_{R}$; (ii) R is right FP-injective if and only if R is right (J, R)-FP-injective. Some known results are improved.

  3. Generalized regular genus for manifolds with boundary

    Directory of Open Access Journals (Sweden)

    Paola Cristofori

    2003-05-01

    Full Text Available We introduce a generalization of the regular genus, a combinatorial invariant of PL manifolds ([10], which is proved to be strictly related, in dimension three, to generalized Heegaard splittings defined in [12].

  4. Geometric regularizations and dual conifold transitions

    International Nuclear Information System (INIS)

    Landsteiner, Karl; Lazaroiu, Calin I.

    2003-01-01

    We consider a geometric regularization for the class of conifold transitions relating D-brane systems on noncompact Calabi-Yau spaces to certain flux backgrounds. This regularization respects the SL(2,Z) invariance of the flux superpotential, and allows for computation of the relevant periods through the method of Picard-Fuchs equations. The regularized geometry is a noncompact Calabi-Yau which can be viewed as a monodromic fibration, with the nontrivial monodromy being induced by the regulator. It reduces to the original, non-monodromic background when the regulator is removed. Using this regularization, we discuss the simple case of the local conifold, and show how the relevant field-theoretic information can be extracted in this approach. (author)

  5. Fast and compact regular expression matching

    DEFF Research Database (Denmark)

    Bille, Philip; Farach-Colton, Martin

    2008-01-01

    We study 4 problems in string matching, namely, regular expression matching, approximate regular expression matching, string edit distance, and subsequence indexing, on a standard word RAM model of computation that allows logarithmic-sized words to be manipulated in constant time. We show how...... to improve the space and/or remove a dependency on the alphabet size for each problem using either an improved tabulation technique of an existing algorithm or by combining known algorithms in a new way....

  6. Regular-fat dairy and human health

    DEFF Research Database (Denmark)

    Astrup, Arne; Bradley, Beth H Rice; Brenna, J Thomas

    2016-01-01

    In recent history, some dietary recommendations have treated dairy fat as an unnecessary source of calories and saturated fat in the human diet. These assumptions, however, have recently been brought into question by current research on regular fat dairy products and human health. In an effort to......, cheese and yogurt, can be important components of an overall healthy dietary pattern. Systematic examination of the effects of dietary patterns that include regular-fat milk, cheese and yogurt on human health is warranted....

  7. Deterministic automata for extended regular expressions

    Directory of Open Access Journals (Sweden)

    Syzdykov Mirzakhmet

    2017-12-01

    Full Text Available In this work we present the algorithms to produce deterministic finite automaton (DFA for extended operators in regular expressions like intersection, subtraction and complement. The method like “overriding” of the source NFA(NFA not defined with subset construction rules is used. The past work described only the algorithm for AND-operator (or intersection of regular languages; in this paper the construction for the MINUS-operator (and complement is shown.

  8. Regularities of intermediate adsorption complex relaxation

    International Nuclear Information System (INIS)

    Manukova, L.A.

    1982-01-01

    The experimental data, characterizing the regularities of intermediate adsorption complex relaxation in the polycrystalline Mo-N 2 system at 77 K are given. The method of molecular beam has been used in the investigation. The analytical expressions of change regularity in the relaxation process of full and specific rates - of transition from intermediate state into ''non-reversible'', of desorption into the gas phase and accumUlation of the particles in the intermediate state are obtained

  9. Online Manifold Regularization by Dual Ascending Procedure

    OpenAIRE

    Sun, Boliang; Li, Guohui; Jia, Li; Zhang, Hui

    2013-01-01

    We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offline to online in this paper. Our algorithms are derived by gradient ascent in the dual function. For practical purpose, we propose two buffering strategies and two sparse approximations to reduce the computational complexity. Detailed experiments verify the utility of our approache...

  10. Waiting for Shadows from the Distant Solar System

    Science.gov (United States)

    Kohler, Susanna

    2016-03-01

    How can we hope to measure the hundreds of thousands of objects in our distant solar system? A team of astronomers is harnessing citizen science to begin to tackle this problem!A light curve from an occultation collected by a RECON site in Quincy, California. As the objects shadow passes, the background stars light dims. [RECON/Charley Arrowsmith (Feather River College)]Occultation InformationEstimates currently place the number of Kuiper belt objects larger than 100 km across at over 100,000. Knowing the sizes and characteristics of these objects is important for understanding the composition of the outer solar system and constraining models of the solar systems formation and evolution.Unfortunately, measuring small, dim bodies at large distances is incredibly difficult! One of the best ways to obtain the sizes of these objects is to watch as they occult a distant star. Timing the object as it passes across the face of the star can give us a good measure of its size and shape, when observed from multiple stations in the path of the shadow.An Extended NetworkOccultations by nearby objects (like main-belt asteroids) can be predicted fairly accurately, but those by trans-Neptunian objects are much more poorly constrained. Only ~900 trans-Neptunian objects have approximately known paths, and occultation-shadow predictions for these objects are often only accurate to ~1000km on the Earths surface. So how can we ensure that theres a telescope in the right location, ready to observe when an occultation occurs?Map of the 56 RECON sites distributed over 2000 km in the western United States. [Buie et al. 2016]The simplest answer is to set up a huge network of observing stations, and wait for the shadows to come to the network. With this approach, even if the predicted path isnt precisely known, some of the stations will still observe the occultation.Due to the number of stations needed, this project lends itself perfectly to citizen science. In a recently published paper by

  11. Mathematical modelling of the complete metrology of the PROBA-3/ASPIICS formation flying solar coronagraph

    Science.gov (United States)

    Stathopoulos, F.; Vives, S.; Damé, L.; Tsinganos, K.

    2017-11-01

    Formation flying, with ESA's mission PROBA-3, is providing the chance of creating a giant solar coronagraph in Space. The scientific payload, the solar coronagraph ASPIICS, has been selected in January 2009 [1]. The advantages of formation flying are: 1) larger dimensions for the coronagraph, which leads to better spatial resolution and lower straylight level and 2) possibility of continuous observations of the inner corona. The PROBA-3/ASPIICS mission is composed of two spacecrafts (S/Cs) at 150 meters distance, the Occulter-S/C (O-S/C) which holds the external occulter, and the Coronagraph-S/C (C-S/C) which holds the main instrument, i.e. the telescope. In addition of the scientific capabilities of the instrument, it will continuously monitor the exact position and pointing of both S/Cs in 3D space, via two additional metrology units: the Shadow Position Sensor (SPS) and the Occulter Position Sensor (OPS). In this paper we are presenting the metrology of this formation flying mission combining the outputs of the above mentioned sensors, SPS and OPS. This study has been conducted in the framework of an ESA "STARTIGER" initiative, a novel approach aimed at demonstrating the feasibility of a new and promising technology concept (in our case formation flying applied to solar coronagraphy, cf. [2, 3]) on a short time scale (six months study).

  12. Solar energy

    International Nuclear Information System (INIS)

    Kruisheer, N.

    1992-01-01

    In five brief articles product information is given on solar energy applications with special attention to the Netherlands. After an introduction on solar energy availability in the Netherlands the developments in solar boiler techniques are dealt with. Solar water heaters have advantages for the environment, and government subsidies stimulate different uses of such water heaters. Also the developments of solar cells show good prospects, not only for developing countries, but also for the industrialized countries. In brief the developments in solar energy storage and the connection of solar equipment to the grid are discussed. Finally attention is paid to the applications of passive solar energy in the housing construction, the use of transparent thermal insulation and the developments of translucent materials. 18 figs., 18 ills

  13. Solar Imagery

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar photographic and illustrated datasets contributed by a number of national and private solar observatories located worldwide....

  14. Solar Features

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of solar feature datasets contributed by a number of national and private solar observatories located worldwide.

  15. Solar Indices

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  16. Prediction of occult hepatitis B virus infection in liver transplant donors through hepatitis B virus blood markers.

    Science.gov (United States)

    Tandoi, Francesco; Caviglia, Gian Paolo; Pittaluga, Fabrizia; Abate, Maria Lorena; Smedile, Antonina; Romagnoli, Renato; Salizzoni, Mauro

    2014-11-01

    Occult hepatitis B virus infection is defined as detectable HBV-DNA in liver of HBsAg-negative individuals, with or without detectable serum HBV-DNA. In deceased liver donors, results of tissue analysis cannot be obtained prior to allocation for liver transplantation. we investigated prevalence and predictability of occult hepatitis B using blood markers of viral exposure/infection in deceased liver donors. In 50 consecutive HBsAg-negative/anti-HBc-positive and 20 age-matched HBsAg-negative/anti-HBc-negative donors, a nested-PCR assay was employed in liver biopsies for diagnosis of occult hepatitis B according to Taormina criteria. All donors were characterized for plasma HBV-DNA and serum anti-HBs/anti-HBe. In liver tissue, occult hepatitis B was present in 30/50 anti-HBc-positive (60%) and in 0/20 anti-HBc-negative donors (pdonors with detectable HBV-DNA in plasma (n=5) or anti-HBs>1,000 mIU/mL (n=5) eventually showed occult infection, i.e, 10/30 occult hepatitis B-positive donors which could have been identified prior to transplantation. In the remaining 40 anti-HBc-positive donors, probability of occult infection was 62% for anti-HBe-positive and/or anti-HBs ≥ 58 mIU/mL; 29% for anti-HBe-negative and anti-HBsdonors, combining anti-HBc with other blood markers of hepatitis B exposure/infection allows to predict occult hepatitis B with certainty and speed in one third of cases. These findings might help refine the allocation of livers from anti-HBc-positive donors. Copyright © 2014 Editrice Gastroenterologica Italiana S.r.l. Published by Elsevier Ltd. All rights reserved.

  17. Solar Special

    International Nuclear Information System (INIS)

    Van Roekel, A.; Osborne, J.; Schroeter, S.; De Jong, R.; De Saint Jacob, Y.

    2009-01-01

    Solar power is growing much faster than most policymakers and analysts realise. As costs come down and feed-in tariffs go up across Europe, a number of countries have started in pursuit of market leader Germany. But in Germany criticism is growing of the multi-billion-euro support schemes that keep the solar industry booming. In this section of the magazine several articles are dedicated to developments in solar energy in Europe. The first article is an overview story on the strong growing global market for solar cells, mainly thanks to subsidy schemes. The second article is on the position of foreign companies in the solar market in Italy. Article number three is dedicated to the conditions for solar technology companies to establish themselves in the German state of Saxony. Also the fifth article deals with the development of solar cells in Saxony: scientists, plant manufacturers and module producers in Saxony are working on new technologies that can be used to produce solar electricity cost-effectively. The goal is to bring the price down to match that of conventionally generated electricity within the next few years. The sixth article deals with the the solar power market in Belgium, which may be overheated or 'oversubsidized'. Article seven is on France, which used to be a pioneer in solar technology, but now produces only a fraction of the solar output of market leader Germany. However, new attractive feed-in-tariffs are changing the solar landscape drastically

  18. Regularized Biot-Savart Laws for Modeling Magnetic Flux Ropes

    Science.gov (United States)

    Titov, Viacheslav; Downs, Cooper; Mikic, Zoran; Torok, Tibor; Linker, Jon A.

    2017-08-01

    Many existing models assume that magnetic flux ropes play a key role in solar flares and coronal mass ejections (CMEs). It is therefore important to develop efficient methods for constructing flux-rope configurations constrained by observed magnetic data and the initial morphology of CMEs. As our new step in this direction, we have derived and implemented a compact analytical form that represents the magnetic field of a thin flux rope with an axis of arbitrary shape and a circular cross-section. This form implies that the flux rope carries axial current I and axial flux F, so that the respective magnetic field is a curl of the sum of toroidal and poloidal vector potentials proportional to I and F, respectively. The vector potentials are expressed in terms of Biot-Savart laws whose kernels are regularized at the rope axis. We regularized them in such a way that for a straight-line axis the form provides a cylindrical force-free flux rope with a parabolic profile of the axial current density. So far, we set the shape of the rope axis by tracking the polarity inversion lines of observed magnetograms and estimating its height and other parameters of the rope from a calculated potential field above these lines. In spite of this heuristic approach, we were able to successfully construct pre-eruption configurations for the 2009 February13 and 2011 October 1 CME events. These applications demonstrate that our regularized Biot-Savart laws are indeed a very flexible and efficient method for energizing initial configurations in MHD simulations of CMEs. We discuss possible ways of optimizing the axis paths and other extensions of the method in order to make it more useful and robust.Research supported by NSF, NASA's HSR and LWS Programs, and AFOSR.

  19. Amplification and protein overexpression of cyclin D1: Predictor of occult nodal metastasis in early oral cancer.

    Science.gov (United States)

    Noorlag, Rob; Boeve, Koos; Witjes, Max J H; Koole, Ronald; Peeters, Ton L M; Schuuring, Ed; Willems, Stefan M; van Es, Robert J J

    2017-02-01

    Accurate nodal staging is pivotal for treatment planning in early (stage I-II) oral cancer. Unfortunately, current imaging modalities lack sensitivity to detect occult nodal metastases. Chromosomal region 11q13, including genes CCND1, Fas-associated death domain (FADD), and CTTN, is often amplified in oral cancer with nodal metastases. However, evidence in predicting occult nodal metastases is limited. In 158 patients with early tongue and floor of mouth (FOM) squamous cell carcinomas, both CCND1 amplification and cyclin D1, FADD, and cortactin protein expression were correlated with occult nodal metastases. CCND1 amplification and cyclin D1 expression correlated with occult nodal metastases. Cyclin D1 expression was validated in an independent multicenter cohort, confirming the correlation with occult nodal metastases in early FOM cancers. Cyclin D1 is a predictive biomarker for occult nodal metastases in early FOM cancers. Prospective research on biopsy material should confirm these results before implementing its use in routine clinical practice. © 2016 Wiley Periodicals, Inc. Head Neck 39: 326-333, 2017. © 2016 Wiley Periodicals, Inc.

  20. Improvements in GRACE Gravity Fields Using Regularization

    Science.gov (United States)

    Save, H.; Bettadpur, S.; Tapley, B. D.

    2008-12-01

    The unconstrained global gravity field models derived from GRACE are susceptible to systematic errors that show up as broad "stripes" aligned in a North-South direction on the global maps of mass flux. These errors are believed to be a consequence of both systematic and random errors in the data that are amplified by the nature of the gravity field inverse problem. These errors impede scientific exploitation of the GRACE data products, and limit the realizable spatial resolution of the GRACE global gravity fields in certain regions. We use regularization techniques to reduce these "stripe" errors in the gravity field products. The regularization criteria are designed such that there is no attenuation of the signal and that the solutions fit the observations as well as an unconstrained solution. We have used a computationally inexpensive method, normally referred to as "L-ribbon", to find the regularization parameter. This paper discusses the characteristics and statistics of a 5-year time-series of regularized gravity field solutions. The solutions show markedly reduced stripes, are of uniformly good quality over time, and leave little or no systematic observation residuals, which is a frequent consequence of signal suppression from regularization. Up to degree 14, the signal in regularized solution shows correlation greater than 0.8 with the un-regularized CSR Release-04 solutions. Signals from large-amplitude and small-spatial extent events - such as the Great Sumatra Andaman Earthquake of 2004 - are visible in the global solutions without using special post-facto error reduction techniques employed previously in the literature. Hydrological signals as small as 5 cm water-layer equivalent in the small river basins, like Indus and Nile for example, are clearly evident, in contrast to noisy estimates from RL04. The residual variability over the oceans relative to a seasonal fit is small except at higher latitudes, and is evident without the need for de-striping or

  1. Observing Tropospheric Water Vapor by Radio Occultation using the Global Positioning System

    Science.gov (United States)

    Kursinski, E. R.; Hajj, G. A.; Hardy, K. R.; Romans, L. J.; Schofield, J. T.

    1995-01-01

    Given the importance of water vapor to weather, climate and hydrology, global humidity observations from satellites are critical. At low latitudes, radio occultation observations of Earth's atmosphere using the Global Positioning System (GPS) satellites allow water vapor profiles to be retrieved with accuracies of 10 to 20% below 6 to 7 km altitude and approx. 5% or better within the boundary layer. GPS observations provide a unique combination of accuracy, vertical resolution (less than or equal to 1 km) and insensitivity to cloud and aerosol particles that is well suited to observations of the lower troposphere. These characteristics combined with the inherent stability of radio occultation observations make it an excellent candidate for the measurement of long term trends.

  2. Photometry of occultation candidate stars. I - Uranus 1985 and Saturn 1985-1991

    Science.gov (United States)

    French, L. M.; Morales, G.; Dalton, A. S.; Klavetter, J. J.; Conner, S. R.

    1985-01-01

    Photometric observations of five stars to be occulted by the rings around Uranus are presented. The four stars to be occulted by Saturn or its rings during the period 1985-1991 were also observed. The observations were carried out with a CCD detector attached to the Kitt Peak McGraw-Hill 1.30-m telescope. Landolt standards of widely ranging V-I color indices were used to determine the extinction coefficients, transformation coefficients, and zero points of the stars. Mean extinction coefficients are given for each night of observation. K magnitudes for each star were estimated on the basis of the results of Johnson (1967). The complete photometric data set is given in a series of tables.

  3. Lunar occultation of Saturn. II - The normal reflectance of Rhea, Titan, and Iapetus

    Science.gov (United States)

    Elliot, J. L.; Dunham, E. W.; Veverka, J.; Goguen, J.

    1978-01-01

    An inversion procedure to obtain the reflectance of the central region of a satellite's disk from lunar occultation data is presented. The scheme assumes that the limb darkening of the satellite depends only on the radial distance from the center of the disk. Given this assumption, normal reflectances can be derived that are essentially independent of the limb darkening and the diameter of the satellite. The procedure has been applied to our observations of the March 1974 lunar occultation of Tethys, Dione, Rhea, Titan, and Iapetus. In the V passband we derive the following normal reflectances: Rhea (0.97 plus or minus 0.20), Titan (0.24 plus or minus 0.03), Iapetus, bright face (0.60 plus or minus 0.14). For Tethys and Dione the values derived have large uncertainties, but are consistent with our result for Rhea.

  4. Solar Indices - Solar Radio Flux

    Data.gov (United States)

    National Oceanic and Atmospheric Administration, Department of Commerce — Collection includes a variety of indices related to solar activity contributed by a number of national and private solar observatories located worldwide. This...

  5. Incidence of occult leiomyosarcoma in presumed morcellation cases: a database study.

    Science.gov (United States)

    Rodriguez, Ana M; Asoglu, Mehmet R; Sak, Muhammet Erdal; Tan, Alai; Borahay, Mostafa A; Kilic, Gokhan S

    2016-02-01

    Our objective was to estimate the incidence of uterine leiomyosarcoma in patients with leiomyomas following laparoscopic supracervical hysterectomy and myomectomy procedures. For this study, we analyzed records of 13,964 women aged 25-64 years who underwent laparoscopic supracervical hysterectomies or myomectomies for leiomyomas from 2002 to 2011 using Clinformatics DataMart. Patient records were divided into two groups: history of laparoscopic supracervical hysterectomy and history of myomectomy. Subjects were tracked to identify diagnosis of leiomyosarcoma within 1 year of the procedure. We analyzed data from the 25-39, 40-49, and 50-64 age brackets. Evidence was obtained from a cohort study from national private insurance claims in the US. Our results showed the incidence of occult leiomyosarcoma developing within 1 year following supracervical hysterectomy using a laparoscopic-assisted approach are 9.8, 10.7, and 33.4 per 10,000 for the 25-39, 40-49, and 50-64 age brackets, respectively; the overall incidence rate is 13.1 per 10,000. The incidence rate of occult leiomyosarcoma developing within 1 year following myomectomy using a laparoscopic-assisted approach are 0.0, 33.8, and 90.1 per 10,000 for the 25-39, 40-49, and 50-64 age brackets, respectively; the overall incidence rate is 17.3 per 10,000. Our analysis shows the overall risk of being diagnosed with occult leiomyosarcoma is 12.9 per 10,000 in laparoscopic-assisted supracervical hysterectomy and myomectomy for patients younger than 49. There is no evidence of occult leiomyosarcoma 1 year after operation for patients younger than 40 who underwent laparoscopic myomectomy. Copyright © 2015. Published by Elsevier Ireland Ltd.

  6. The occult nature of intramedullary spinal cord metastases from renal cell carcinoma.

    LENUS (Irish Health Repository)

    Zakaria, Zaitun

    2012-01-01

    Renal cell carcinomas (RCC) are characterised by a tendency to metastasise widely, often while remaining occult. Intramedullary spinal cord metastases (ISCM) from RCC may be the presenting feature of the disease or present at any time in the disease course. This case report discusses an ISCM from RCC which became manifested at the time of resection of the primary tumour. We review the literature published on ISCM from RCC from 1990 to date comparing disease characteristics and presentations.

  7. High prevalence of occult left heart disease in scleroderma-pulmonary hypertension.

    Science.gov (United States)

    Fox, Benjamin D; Shimony, Avi; Langleben, David; Hirsch, Andrew; Rudski, Lawrence; Schlesinger, Robert; Eisenberg, Mark J; Joyal, Dominique; Hudson, Marie; Boutet, Kim; Serban, Alexandrina; Masetto, Ariel; Baron, Murray

    2013-10-01

    Our study aimed to determine the prevalence of occult left-heart disease in patients with scleroderma and pulmonary hypertension. In patients with pulmonary hypertension (mean pulmonary artery pressure (mean PAP)≥25 mmHg), differentiation between pre- and post-capillary pulmonary hypertension has been made according to pulmonary artery wedge pressure (PAWP) less than or more than 15 mmHg, respectively. We performed a retrospective chart review of 107 scleroderma patients. All patients with suspected pulmonary hypertension had routine right or left heart catheterisation with left ventricular end-diastolic pressure (LVEDP) measurement pre-/post-fluid challenge. We extracted demographic, haemodynamic and echocardiographic data. Patients were classified into one of four groups: haemodynamically normal (mean PAP15 mmHg); occult PVH (mean PAP≥25 mmHg, PAWP≤15 mmHg, LVEDP>15 mmHg before or after fluid challenge); and pulmonary arterial hypertension (PAH) (mean PAP≥25 mmHg, PAWP≤15 mmHg and LVEDP≤15 mmHg before or after fluid challenge). 53 out of 107 patients had pulmonary hypertension. Based on the PAWP-based definition, 29 out of 53 had PAH and 24 out of 53 had PVH. After considering the resting and post-fluid-challenge LVEDP, 11 PAH patients were reclassified as occult PVH. The occult PVH group was haemodynamically, echocardiographically and demographically closer to the PVH group than the PAH group. PVH had high prevalence in our scleroderma-pulmonary hypertension population. Distinguishing PAH from PVH with only PAWP may result in some PVH patients being misclassified as having PAH.

  8. Significance of occult hbv infection in patients with chronic hepatitis c

    International Nuclear Information System (INIS)

    Anwar, W.; Sarwar, M.; Saif, M.; Hussain, A.B.; Tariq, W.Z.

    2006-01-01

    Objective: To determine the frequency of occurrence of occult Hepatitis B infection in chronic hepatitis C patients and its impact (if any) on the effectivity of standard chronic hepatitis C treatment. Design: Quasi-experimental study. Place and Duration of Study: The study was conducted at the Department of Medicine, Military Hospital, Rawalpindi, and Virology Department, Armed Forces Institute of Pathology, Rawalpindi, for a period of nine months from January 2003 to September 2003. Patients and Methods: This study was conducted on 30 HBsAg negative patients with chronic hepatitis C liver disease who were receiving combination therapy with interferon and ribavirin. Occult hepatitis B infection was assessed by carrying out HBV DNA by polymerase chain reaction (PCR) in the sera of these patients. Markers of previous hepatitis B infection Le; anti-HBs and total anti-HBc antibodies were also tested. Response to treatment for hepatitis C (with interferon and ribavirin) was assessed at the end of six months of therapy by measuring ALT levels and HCV RNA by PCR in the serum. Results: In our study only one patient (3.33%) was found to be harbouring HBV DNA in the serum detectable by PCR, with markers of previous HBV infection (both anti HBc antibodies and anti HBs antibodies were positive). A total 14 patients (46.67%) had markers of previous HBV infection, while 16 patients (53.33%) had no such sero markers. Twenty five out of 30 patients (83.33%) responded to treatment and 5 (16.66%) turned out to be non-responders. The single case of occult hepatitis B detected in this study responded to hepatitis C treatment. Conclusion: Occult hepatitis B is not a common occurrence in chronic hepatitis C patients and it did not alter the outcome of treatment for hepatitis C in our study. (author)

  9. Outcome of early detection and radiotherapy for occult spinal cord compression

    International Nuclear Information System (INIS)

    Venkitaraman, Ramachandran; Barbachano, Yolanda; Dearnaley, David P.; Parker, Christopher C.; Khoo, Vincent; Huddart, Robert A.; Eeles, Rosalind; Horwich, Alan; Aslam Sohaib, S.

    2007-01-01

    Retrospective analysis in 150 patients with metastatic prostate cancer was conducted to determine whether early detection with MRI spine and treatment of clinically occult spinal cord compromise (SCC) facilitate preservation of neurologic function. Our results suggest that prophylactic radiotherapy for patients with back pain or radiological SCC without neurologic deficit may facilitate preservation of neurologic function. Thus MRI surveillance for SCC may be important for prostate cancer patients with bone metastases

  10. Anemia and thrombocytopenia as initial symptoms of occult breast cancer with bone marrow metastasis

    OpenAIRE

    Liu, Lulu; Zhang, Jingjing; Chen, Mingtai; Ren, Saisai; Liu, Haihui; Zhang, Hao

    2017-01-01

    Abstract Rationale: Occult breast cancer (OBC) is a rare type of breast cancer without any symptoms in the breast and is often presented with initial symptoms of axillary lymph node metastasis or other metastases. The low incidence rates of OBC make it a great challenge to diagnose and cure. Patient concerns: Our case was a 58-year-old female affected by dizziness and fatigue for nearly a month. Blood tests revealed anemia and thrombocytopenia, and pathological results of a bone marrow biopsy...

  11. Efficacy of benazepril hydrochloride to delay the progression of occult dilated cardiomyopathy in Doberman Pinschers.

    Science.gov (United States)

    O'Grady, M R; O'Sullivan, M L; Minors, S L; Horne, R

    2009-01-01

    Angiotensin converting enzyme inhibitors (ACEIs) are recommended in people to treat asymptomatic (occult) dilated cardiomyopathy (DCM). Efficacy of therapy in occult DCM in dogs is unknown. ACEIs, specifically benazepril hydrochloride (BH), will delay the onset of overt DCM in Doberman Pinschers. Ninety-one Doberman Pinschers were studied, 57 dogs received BH, and 34 dogs no ACEI. Retrospective study of the medical records of all Doberman Pinschers with occult DCM that received BH or no ACEI between April 1989 and February 2003. Two criteria of left ventricular enlargement were used for enrollment: one independent of body weight (BW) (C1) and the other indexed to BW (C2). Cox proportional hazards analyses were used to identify variables associated with the onset of overt DCM. On univariate analysis the median time to onset of overt DCM was significantly longer for the benazepril group (for C1: 425 days for BH, 95% confidence interval [CI] 264-625 days; 339 days for no ACEI, CI 172-453 days, P= .02; for C2: 454 days for BH, CI 264-628 days; 356 days for no ACEI, CI 181-547 days, P= .02). The hazard ratio (HR) (benazepril/no ACEI) was 0.57, CI 0.35-0.94, P= .03 for C1; HR = 0.56, CI 0.34-0.93, P= .02 for C2. On multivariate analysis, BH significantly delayed onset of overt DCM (HR [benazepril/no ACEI] = 0.45, CI 0.26-0.78, P < .01, for C1; HR = 0.36, CI 0.21-0.63, P < .01, for C2). BH in particular and ACEIs in general might delay the progression of occult DCM. Prospective studies are warranted to test this theory.

  12. Thermal structure of intense convective clouds derived from GPS radio occultations

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Randel, W. J.; Ho, S. -P.

    2012-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...

  13. Thermal structure of intense convective clouds derived from GPS radio occultations

    DEFF Research Database (Denmark)

    Biondi, Riccardo; Randel, W. J.; Ho, S.-P.

    2011-01-01

    Thermal structure associated with deep convective clouds is investigated using Global Positioning System (GPS) radio occultation measurements. GPS data are insensitive to the presence of clouds, and provide high vertical resolution and high accuracy measurements to identify associated temperature...... behavior. Deep convective systems are identified using International Satellite Cloud Climatology Project (ISCCP) satellite data, and cloud tops are accurately measured using Cloud-Aerosol Lidar with Orthogonal Polarization (CALIPSO) lidar observations; we focus on 53 cases of near-coincident GPS...

  14. Regular Expression Matching and Operational Semantics

    Directory of Open Access Journals (Sweden)

    Asiri Rathnayake

    2011-08-01

    Full Text Available Many programming languages and tools, ranging from grep to the Java String library, contain regular expression matchers. Rather than first translating a regular expression into a deterministic finite automaton, such implementations typically match the regular expression on the fly. Thus they can be seen as virtual machines interpreting the regular expression much as if it were a program with some non-deterministic constructs such as the Kleene star. We formalize this implementation technique for regular expression matching using operational semantics. Specifically, we derive a series of abstract machines, moving from the abstract definition of matching to increasingly realistic machines. First a continuation is added to the operational semantics to describe what remains to be matched after the current expression. Next, we represent the expression as a data structure using pointers, which enables redundant searches to be eliminated via testing for pointer equality. From there, we arrive both at Thompson's lockstep construction and a machine that performs some operations in parallel, suitable for implementation on a large number of cores, such as a GPU. We formalize the parallel machine using process algebra and report some preliminary experiments with an implementation on a graphics processor using CUDA.

  15. Regularities, Natural Patterns and Laws of Nature

    Directory of Open Access Journals (Sweden)

    Stathis Psillos

    2014-02-01

    Full Text Available  The goal of this paper is to sketch an empiricist metaphysics of laws of nature. The key idea is that there are regularities without regularity-enforcers. Differently put, there are natural laws without law-makers of a distinct metaphysical kind. This sketch will rely on the concept of a natural pattern and more significantly on the existence of a network of natural patterns in nature. The relation between a regularity and a pattern will be analysed in terms of mereology.  Here is the road map. In section 2, I will briefly discuss the relation between empiricism and metaphysics, aiming to show that an empiricist metaphysics is possible. In section 3, I will offer arguments against stronger metaphysical views of laws. Then, in section 4 I will motivate nomic objectivism. In section 5, I will address the question ‘what is a regularity?’ and will develop a novel answer to it, based on the notion of a natural pattern. In section 6, I will raise the question: ‘what is a law of nature?’, the answer to which will be: a law of nature is a regularity that is characterised by the unity of a natural pattern.

  16. Coupled solar still, solar heater

    Energy Technology Data Exchange (ETDEWEB)

    Davison, R R; Harris, W B; Moor, D H; Delyannis, A; Delyannis, E [eds.

    1976-01-01

    Computer simulation of combinations of solar stills and solar heaters indicates the probable economic advantage of such an arrangement in many locations if the size of the heater is optimized relative to that of the still. Experience with various low cost solar heaters is discussed.

  17. Solar Magnetism eXplorer (Solme X)

    Science.gov (United States)

    Peter, Hardi; Abbo, L.; Andretta, V.; Auchere, F.; Bemporad, A.; Berrilli, F.; Bommier, V.; Cassini, R.; Curdt, W.; Davila, J.; hide

    2011-01-01

    The magnetic field plays a pivotal role in many fields of Astrophysics. This is especially true for the physics of the solar atmosphere. Measuring the magnetic field in the upper solar atmosphere is crucial to understand the nature of the underlying physical processes that drive the violent dynamics of the solar corona-that can also affect life on Earth. SolmeX, a fully equipped solar space observatory for remote-sensing observations, will provide the first comprehensive measurements of the strength and direction of the magnetic field in the upper solar atmosphere. The mission consists of two spacecraft, one carrying the instruments, and another one in formation flight at a distance of about 200 m carrying the occulter to provide an artificial total solar eclipse. This will ensure high-quality coronagraphic observations above the solar limb. SolmeX integrates two spectro-polarimetric coronagraphs for off-limb observations, one in the EUV and one in the IR, and three instruments for observations on the disk. The latter comprises one imaging polarimeter in the EUV for coronal studies, a spectro-polarimeter in the EUV to investigate the low corona, and an imaging spectro-polarimeter in the UV for chromospheric studies. SOHO and other existing missions have investigated the emission of the upper atmosphere in detail (not considering polarization), and as this will be the case also for missions planned for the near future. Therefore it is timely that SolmeX provides the final piece of the observational quest by measuring the magnetic field in the upper atmosphere through polarimetric observations

  18. The prevalence of visible and/or occult blood on anesthesia and monitoring equipment.

    Science.gov (United States)

    Perry, S M; Monaghan, W P

    2001-02-01

    The Occupational Safety and Health Administration (OSHA) and the Centers for Disease Control and Prevention (CDC) have attempted to stop the spread of blood-borne pathogens by issuing several recommendations and regulations. However, unless healthcare workers comply with these standards, they are not effective. In the anesthesia care environment, the anesthetist is responsible for ensuring that the equipment is clean, and disinfected, before use. We studied the prevalence of visible and occult blood on 6 types of anesthesia and monitoring equipment identified as ready for use in 28 operating suites, in 2 facilities. The sample consisted of 336 observations of the 6 types of equipment. The equipment was inspected for visible blood and then tested for occult blood using a 3-stage phenolphthalein test. Of the 336 observations, 110 (32.7%), were positive for occult blood with only 6 showing visible blood. The presence of blood on this equipment may be in direct violation of the OSHA Blood-borne Pathogen Standard and the infection control guidelines of the American Association of Nurse Anesthetists. Furthermore, the presence of blood on this equipment may increase the risk for nosocomial and occupational exposure to viral and bacterial pathogens. Recommendations were made to decrease the risks from this contamination by redesigning equipment, increasing the use of disposable equipment, and ensuring compliance with effective infection control practices.

  19. The use of MRI and CT in Imaging Occult Hip Fractures

    Directory of Open Access Journals (Sweden)

    Obadă B.

    2014-11-01

    Full Text Available Diagnosis of hip fractures is particularly important due to the high dependence on the integrity of this structure for people to function in their daily lives. Left unrecognized, patients face increasing morbidity and mortality as time from the original injury lengthens. A delay of just 2 days in surgical treatment for an acute hip fracture doubles mortality. In addition, an unrecognized non-displaced fracture may displace, requiring surgery of much higher risk. This may be part of the reason that the most frequent lawsuit against Emergency Physicians is for missed orthopedic injury. We reviewed the use of MRI and CT for occult hip fractures (OHF detection at a major urban trauma unit. Our study is a retrospective review. Inclusion criteria: all patients presenting to the Emergency Clinical Hospital of Constanta with a suspected, posttraumatic, occult hip fracture, over a 5 years period were included. All patients had negative initial radiographs and underwent further imaging with either CT or MRI. A total of 185 cases meeting the inclusion criteria were identified. 72 occult hip fractures were detected with both imaging modalities. Although MRI certainly enables greater image detail, in our experience both modalities are able to provide satisfactory fracture characterization. The choice of imaging should be determined by availability and indication. MRI provides superior imaging of soft tissue but is less sensitive for degenerative changes in presence of bone edema.

  20. Verify Occulter Deployment Tolerances as Part of NASA's Technology Development for Exoplanet Missions

    Science.gov (United States)

    Kasdin, N. J.; Shaklan, S.; Lisman, D.; Thomson, M.; Webb, D.; Cady, E.; Marks, G. W.; Lo, A.

    2013-01-01

    In support of NASA's Exoplanet Exploration Program and the Technology Development for Exoplanet Missions (TDEM), we recently completed a 2 year study of the manufacturability and metrology of starshade petals. An external occult is a satellite employing a large screen, or starshade, that flies in formation with a spaceborne telescope to provide the starlight suppression needed for detecting and characterizing exoplanets. Among the advantages of using an occulter are the broadband allowed for characterization and the removal of light before entering the observatory, greatly relaxing the requirements on the telescope and instrument. This poster presents the results of our successful first TDEM that demonstrated an occulter petal could be built and measured to an accuracy consistent with close to 10^-10 contrast. We also present the progress in our second TDEM to demonstrate the next critical technology milestone: precision deployment of the central truss and petals to the necessary accuracy. We have completed manufacture of four sub-scale petals and a central hub to fit with an existing deployable truss. We show the plans for repeated stow and deploy tests of the assembly and the metrology to confirm that each deploy repeatably meets the absolute positioning requirements of the petals (better than 1.0 mm).

  1. Verifying occulter deployment tolerances as part of NASA's technology development for exoplanet missions

    Science.gov (United States)

    Kasdin, N. J.; Lisman, D.; Shaklan, S.; Thomson, M.; Webb, D.; Cady, E.; Marks, G. W.; Lo, A.

    2013-09-01

    An external occulter is a satellite employing a large screen, or starshade, that flies in formation with a spaceborne telescope to provide the starlight suppression needed for detecting and characterizing exoplanets. Among the advantages of using an occulter are the broadband allowed for characterization and the removal of light before entering the observatory, greatly relaxing the requirements on the telescope and instrument. In support of NASA's Exoplanet Exploration Program and the Technology Development for Exoplanet Missions (TDEM), we recently completed a 2 year study of the manufacturability and metrology of starshade petals. In this paper we review the results of that successful first TDEM which demonstrated an occulter petal could be built and measured to an accuracy consistent with close to 10-10 contrast. We then present the results of our second TDEM to demonstrate the next critical technology milestone: precision deployment of the central truss and petals to the necessary accuracy. We show the deployment of an existing deployable truss outfitted with four sub-scale petals and a custom designed central hub.

  2. The Centaur Chariklo and its rings system from stellar occultations in 2017

    Science.gov (United States)

    Leiva, Rodrigo; Sicardy, Bruno; Camargo, Julio; Ortiz, Jose Luis; Berard, Diane; Desmars, Josselin; Chariklo Occultations Team; Rio Group; Lucky Star Occultation Team; Granada Occultation Team

    2017-10-01

    A stellar occultation in June 3, 2013 revealed the presence of a dense ring system around the Centaur object (10199) Chariklo (Braga-Ribas et al., Nature 2014). Subsequent analysis of occultation data and long-term photometric variations indicate that Chariklo's body is elongated (Leiva et al. 2017, submitted) and that the main ring exhibits significant longitudinal variations of the radial width (Bérard et al. 2017, in press). We report three multi-chord high-quality stellar occultation by Chariklo on April 9, 2017 and June 22, 2017 from Namibia, and July 23 2017 from South America. The analysis of this new data set is underway, but preliminary results are consistent with triaxial ellipsoidal models. From this analysis we will:-present refined models for the size and shape of Chariklo's main body andevaluate the heights and slopes of its topographic features.-give constraints on the longitudinal width variations of Chariklo's rings andexplore the possibility to obtain the rings apsidal precession rate.Chariklo's shape and topography have strong consequences on the dynamics of the rings through Lindblad-type resonances between mean motion of the ring particles and the spin of the main body, while the rings precession rate gives constraints on the dynamical oblateness of the main body.**Part of the research leading to these results has received funding from the European Research Council under the European Community’s H2020 (2014-2020/ ERC Grant Agreement n 669416 ”LUCKY STAR”).

  3. First lunar occultation results from the 2.4 m Thai national telescope equipped with ULTRASPEC

    Energy Technology Data Exchange (ETDEWEB)

    Richichi, A.; Irawati, P.; Soonthornthum, B. [National Astronomical Research Institute of Thailand, 191 Siriphanich Building, Huay Kaew Road, Suthep, Muang, Chiang Mai 50200 (Thailand); Dhillon, V. S. [Department of Physics and Astronomy, University of Sheffield, Sheffield S3 7RH (United Kingdom); Marsh, T. R., E-mail: andrea4work@gmail.com [Department of Physics, University of Warwick, Gibbet Hill Road, Coventry CV4 7AL (United Kingdom)

    2014-11-01

    The recently inaugurated 2.4 m Thai National Telescope (TNT) is equipped with, among other instruments, the ULTRASPEC low-noise, frame-transfer EMCCD camera. At the end of its first official observing season, we report on the use of this facility to record high time resolution imaging using small detector subarrays with a sampling as fast as several 10{sup 2} Hz. In particular, we have recorded lunar occultations of several stars that represent the first contribution to this area of research made from Southeast Asia with a telescope of this class. Among the results, we discuss an accurate measurement of α Cnc, which has been reported previously as a suspected close binary. Attempts by several authors to resolve this star have so far met with a lack of unambiguous confirmation. With our observation we are able to place stringent limits on the projected angular separation (<0.''003) and brightness (Δm > 5) of a putative companion. We also present a measurement of the binary HR 7072, which extends considerably the time coverage available for its yet undetermined orbit. We discuss our precise determination of the flux ratio and projected separation in the context of other available data. We conclude by providing an estimate of the performance of ULTRASPEC at TNT for lunar occultation work. This facility can help to extend the lunar occultation technique in a geographical area where no comparable resources were available until now.

  4. Astrometry of the Orcus/Vanth occultation on UT 7 March 2017

    Science.gov (United States)

    Bosh, Amanda S.; Zuluaga, Carlos; Levine, Stephen; Sickafoose, Amanda A.; Genade, Anja; Schindler, Karsten; Lister, Tim; Person, Michael J.

    2017-10-01

    On UT 7 March 2017, Orcus was predicted to occult a star with m=14.3. Observations were made at five observatories: the 0.6-m Astronomical Telescope of the University of Stuttgart (ATUS) at Sierra Remote Observatories (SRO), California; Las Cumbres Observatory’s 1-m telescope (ELP) at McDonald Observatory, Fort Davis, Texas; NASA’s 3-m InfraRed Telescope Facility (IRTF) on Mauna Kea, Hawaii; the 4.1-m Southern Astrophysical Research telescope (SOAR) on Cerro Pachón, Chile; and the 0.6-m Southeastern Association for Research in Astronomy telescope (SARA-CT) at Cerro Tololo, Chile. While observations at all sites were successful, only two—ELP and IRTF—observed solid-body occultation signatures. We will discuss the various predictions for this event and the reasons for the differences among them, including an offset of 130 mas for the star position from the position in the Gaia catalog. The sum of the positive and negative detections place constraints on the geometry of the Orcus/Vanth system, and we present our astrometric results for the geometric solution for this occultation. The implications of the light curve analyses are presented by Sickafoose et al., this conference.

  5. Usefullness of routine use of fecal occult blood test in a hospital setting

    Directory of Open Access Journals (Sweden)

    Simona Ravnik

    2006-12-01

    Full Text Available Background: Fecal occult blood test, hematest, is a well excepted non-invasive method used for detecting different diseases of the gastrointestinal tract. It was proven in different randomized studies that usage of this simple method may facilitate further diagnostic and therapeutic treatment.Patients and methods: The retrospective analysis includes patients, which were admitted to the gastroenterological and endoscopy department of the General hospital Maribor in the last quarter of the year 2005. In all patients fecal occult blood test was performed.Results: We examined 200 patients, 104 women and 96 men, average age 63.9 years, SD±16.9, ranging from 21 to 97 years. Positive hematest was discovered in 76 patients (38 %. The source of hemorrhage from the upper digestive tract was confirmed in 37 patients (48.6 % of all positive tests and from the lower digestive tract in 34 patients (46 % of all positive tests. The most frequent causes of hemorrhage from the lower digestive tract were chronic inflammatory bowel disease (13.1 % of all positive tests, colorectal cancer (10.5 % and polyps (6.6 %. The source of hemorrhage was not located in five patients (6.6 % of all positive tests despite the accurate diagnostic procedure.Conclusions: By performing a fecal occult blood screening in non-symptomatic patients, we can make an essential step towards discovering different gastrointestinal diseases, even colorectal cancer in its early, limited form, when the effect of treatment is greatest.

  6. Solar Sailing

    Science.gov (United States)

    Johnson, Les

    2009-01-01

    Solar sailing is a topic of growing technical and popular interest. Solar sail propulsion will make space exploration more affordable and offer access to destinations within (and beyond) the solar system that are currently beyond our technical reach. The lecture will describe solar sails, how they work, and what they will be used for in the exploration of space. It will include a discussion of current plans for solar sails and how advanced technology, such as nanotechnology, might enhance their performance. Much has been accomplished recently to make solar sail technology very close to becoming an engineering reality and it will soon be used by the world s space agencies in the exploration of the solar system and beyond. The first part of the lecture will summarize state-of-the-art space propulsion systems and technologies. Though these other technologies are the key to any deep space exploration by humans, robots, or both, solar-sail propulsion will make space exploration more affordable and offer access to distant and difficult destinations. The second part of the lecture will describe the fundamentals of space solar sail propulsion and will describe the near-, mid- and far-term missions that might use solar sails as a propulsion system. The third part of the lecture will describe solar sail technology and the construction of current and future sailcraft, including the work of both government and private space organizations.

  7. Fractional Regularization Term for Variational Image Registration

    Directory of Open Access Journals (Sweden)

    Rafael Verdú-Monedero

    2009-01-01

    Full Text Available Image registration is a widely used task of image analysis with applications in many fields. Its classical formulation and current improvements are given in the spatial domain. In this paper a regularization term based on fractional order derivatives is formulated. This term is defined and implemented in the frequency domain by translating the energy functional into the frequency domain and obtaining the Euler-Lagrange equations which minimize it. The new regularization term leads to a simple formulation and design, being applicable to higher dimensions by using the corresponding multidimensional Fourier transform. The proposed regularization term allows for a real gradual transition from a diffusion registration to a curvature registration which is best suited to some applications and it is not possible in the spatial domain. Results with 3D actual images show the validity of this approach.

  8. Regular non-twisting S-branes

    International Nuclear Information System (INIS)

    Obregon, Octavio; Quevedo, Hernando; Ryan, Michael P.

    2004-01-01

    We construct a family of time and angular dependent, regular S-brane solutions which corresponds to a simple analytical continuation of the Zipoy-Voorhees 4-dimensional vacuum spacetime. The solutions are asymptotically flat and turn out to be free of singularities without requiring a twist in space. They can be considered as the simplest non-singular generalization of the singular S0-brane solution. We analyze the properties of a representative of this family of solutions and show that it resembles to some extent the asymptotic properties of the regular Kerr S-brane. The R-symmetry corresponds, however, to the general lorentzian symmetry. Several generalizations of this regular solution are derived which include a charged S-brane and an additional dilatonic field. (author)

  9. Online Manifold Regularization by Dual Ascending Procedure

    Directory of Open Access Journals (Sweden)

    Boliang Sun

    2013-01-01

    Full Text Available We propose a novel online manifold regularization framework based on the notion of duality in constrained optimization. The Fenchel conjugate of hinge functions is a key to transfer manifold regularization from offline to online in this paper. Our algorithms are derived by gradient ascent in the dual function. For practical purpose, we propose two buffering strategies and two sparse approximations to reduce the computational complexity. Detailed experiments verify the utility of our approaches. An important conclusion is that our online MR algorithms can handle the settings where the target hypothesis is not fixed but drifts with the sequence of examples. We also recap and draw connections to earlier works. This paper paves a way to the design and analysis of online manifold regularization algorithms.

  10. Regular transport dynamics produce chaotic travel times.

    Science.gov (United States)

    Villalobos, Jorge; Muñoz, Víctor; Rogan, José; Zarama, Roberto; Johnson, Neil F; Toledo, Benjamín; Valdivia, Juan Alejandro

    2014-06-01

    In the hope of making passenger travel times shorter and more reliable, many cities are introducing dedicated bus lanes (e.g., Bogota, London, Miami). Here we show that chaotic travel times are actually a natural consequence of individual bus function, and hence of public transport systems more generally, i.e., chaotic dynamics emerge even when the route is empty and straight, stops and lights are equidistant and regular, and loading times are negligible. More generally, our findings provide a novel example of chaotic dynamics emerging from a single object following Newton's laws of motion in a regularized one-dimensional system.

  11. Regularity of difference equations on Banach spaces

    CERN Document Server

    Agarwal, Ravi P; Lizama, Carlos

    2014-01-01

    This work introduces readers to the topic of maximal regularity for difference equations. The authors systematically present the method of maximal regularity, outlining basic linear difference equations along with relevant results. They address recent advances in the field, as well as basic semigroup and cosine operator theories in the discrete setting. The authors also identify some open problems that readers may wish to take up for further research. This book is intended for graduate students and researchers in the area of difference equations, particularly those with advance knowledge of and interest in functional analysis.

  12. PET regularization by envelope guided conjugate gradients

    International Nuclear Information System (INIS)

    Kaufman, L.; Neumaier, A.

    1996-01-01

    The authors propose a new way to iteratively solve large scale ill-posed problems and in particular the image reconstruction problem in positron emission tomography by exploiting the relation between Tikhonov regularization and multiobjective optimization to obtain iteratively approximations to the Tikhonov L-curve and its corner. Monitoring the change of the approximate L-curves allows us to adjust the regularization parameter adaptively during a preconditioned conjugate gradient iteration, so that the desired solution can be reconstructed with a small number of iterations

  13. Matrix regularization of embedded 4-manifolds

    International Nuclear Information System (INIS)

    Trzetrzelewski, Maciej

    2012-01-01

    We consider products of two 2-manifolds such as S 2 ×S 2 , embedded in Euclidean space and show that the corresponding 4-volume preserving diffeomorphism algebra can be approximated by a tensor product SU(N)⊗SU(N) i.e. functions on a manifold are approximated by the Kronecker product of two SU(N) matrices. A regularization of the 4-sphere is also performed by constructing N 2 ×N 2 matrix representations of the 4-algebra (and as a byproduct of the 3-algebra which makes the regularization of S 3 also possible).

  14. Atmospheric gravity wave detection following the 2011 Tohoku earthquakes combining COSMIC occultation and GPS observations

    Science.gov (United States)

    Yan, X.; Tao, Y.; Xia, C.; Qi, Y.; Zuo, X.

    2017-12-01

    Several studies have reported the earthquake-induced atmospheric gravity waves detected by some new technologies such as airglow (Makela et al., 2011), GOCE (Garcia et al., 2013), GRACE (Yang et al., 2014), F3/C radio occultation sounding (Coïsson et al., 2015). In this work, we collected all occultation events on 11 March, and selected four events to analyze at last. The original and filtered podTEC is represented as function of the altitude of the impact parameter and UT of the four events. Then, the travel time diagrams of filtered podTEC derived from the events were analyzed. The occultation signal from one event (marked as No.73) is consistent with the previous results reported by Coïsson. 2015, which is corresponds to the ionospheric signal induced from tsunami gravity wave. What is noticeable, in this work, is that three occultation events of No.403, 77 and 118 revealed a disturbance of atmospheric gravity wave with velocity 300m/s, preceding the tsunami. It would probably be correspond to the gravity waves caused by seismic rupture but not tsunami. In addition, it can be seen that the perturbation height of occultation observation TEC is concentrated at 200-400km, corresponding ionosphere F region. The signals detected above are compared with GPS measurements of TEC from GEONET and IGS. From GPS data, traveling ionospheric disturbances were observed spreading out from the epicenter as a quasi-circular propagation pattern with the time. Exactly, we observed an acoustic wave coupled with Rayleigh wave starting from the epicenter with a speed of 3.0km/s and a superimposed acoustic-gravity wave moving with a speed of 800m/s. The acoustic-gravity wave generated at the epicenter and gradually attenuated 800km away, then it is replaced by a gravity wave coupled with the tsunami that moves with a speed of between 100 and 300m/s. It is necessary to confirm the propagation process of the waves if we attempt to evaluate the use of ionospheric seismology as a

  15. On a correspondence between regular and non-regular operator monotone functions

    DEFF Research Database (Denmark)

    Gibilisco, P.; Hansen, Frank; Isola, T.

    2009-01-01

    We prove the existence of a bijection between the regular and the non-regular operator monotone functions satisfying a certain functional equation. As an application we give a new proof of the operator monotonicity of certain functions related to the Wigner-Yanase-Dyson skew information....

  16. Occult Intra-articular Knee Injuries in Children With Hemarthrosis.

    Science.gov (United States)

    Askenberger, Marie; Ekström, Wilhelmina; Finnbogason, Thröstur; Janarv, Per-Mats

    2014-07-01

    Hemarthrosis after acute knee trauma is a sign of a potentially serious knee injury. Few studies have described the epidemiology and detailed injury spectrum of acute knee injuries in a general pediatric population. To document the current injury spectrum of acute knee injuries with hemarthrosis in children aged 9 to 14 years and to describe the distribution of sex, age at injury, type of activity, and activity frequency in this population. Descriptive epidemiology study. All patients in the Stockholm County area aged 9 to 14 years who suffered acute knee trauma with hemarthrosis were referred to Astrid Lindgren Children's Hospital, Karolinska University Hospital, from September 2011 to April 2012. The patients underwent clinical examination, radiography, and magnetic resonance imaging (MRI). The type of activity when injured, regular sports activity/frequency, and patient sex and age were registered. The diagnoses were classified into minor and serious injuries. The study included 117 patients (47 girls and 70 boys; mean age, 13.2 years). Seventy percent had a serious knee injury. Lateral patellar dislocations, anterior cruciate ligament ruptures, and anterior tibial spine fractures were the most common injuries, with an incidence of 0.6, 0.2, and 0.1 per 1000 children, respectively. The sex distribution was equal up to age 13 years; twice as many boys were seen at the age of 14 years. The majority of injuries occurred during sports. Forty-six patients (39%) had radiographs without a bony injury but with a serious injury confirmed on MRI. Seventy percent of the patients aged 9 to 14 years with traumatic knee hemarthrosis had a serious intra-articular injury that needed specific medical attention. Fifty-six percent of these patients had no visible injury on plain radiographs. Physicians who treat this group of patients should consider MRI to establish the diagnosis when there is no or minimal radiographic findings. The most common serious knee injury was a lateral

  17. Occult hepatitis B virus coinfection in HIV-positive African migrants to the UK: a point prevalence study.

    Science.gov (United States)

    Chadwick, D; Doyle, T; Ellis, S; Price, D; Abbas, I; Valappil, M; Geretti, A M

    2014-03-01

    Occult (surface antigen-negative/DNA-positive) hepatitis B virus (HBV) infection is common in areas of the world where HBV is endemic. The main objectives of this study were to determine the prevalence of occult HBV infection in HIV-infected African migrants to the UK and to determine factors associated with occult coinfection. This anonymized point-prevalence study identified Africans attending three HIV clinics, focussing on patients naïve to antiretroviral therapy (ART). Stored blood samples were tested for HBV DNA. Prevalence was calculated in the entire cohort, as well as in subpopulations. Risk factors for occult HBV coinfection were identified using logistic regression analysis. Among 335 HIV-positive African migrants, the prevalence of occult HBV coinfection was 4.5% [95% confidence interval (CI) 2.8-7.4%] overall, and 6.5% (95% CI 3.9-10.6%) and 0.8% (95% CI 0.2-4.6%) in ART-naïve and ART-experienced patients, respectively. Among ART-naïve anti-HBV core (anti-HBc)-positive patients, the prevalence was 16.4% (95% CI 8.3-25.6%). The strongest predictor of occult coinfection was anti-HBc positivity [odds ratio (OR) 7.4; 95% CI 2.0-27.6]. Median HBV DNA and ALT levels were 54 IU/mL [interquartile range (IQR) 33-513 IU/mL] and 22 U/L (IQR 13-27 U/L), respectively. Occult HBV coinfection remains under-diagnosed in African HIV-infected patients in the UK. Given the range of HBV DNA levels observed, further studies are warranted to determine its clinical significance and to guide screening strategies and ART selection in these patients. © 2013 British HIV Association.

  18. Regularity and irreversibility of weekly travel behavior

    NARCIS (Netherlands)

    Kitamura, R.; van der Hoorn, A.I.J.M.

    1987-01-01

    Dynamic characteristics of travel behavior are analyzed in this paper using weekly travel diaries from two waves of panel surveys conducted six months apart. An analysis of activity engagement indicates the presence of significant regularity in weekly activity participation between the two waves.

  19. Regular and context-free nominal traces

    DEFF Research Database (Denmark)

    Degano, Pierpaolo; Ferrari, Gian-Luigi; Mezzetti, Gianluca

    2017-01-01

    Two kinds of automata are presented, for recognising new classes of regular and context-free nominal languages. We compare their expressive power with analogous proposals in the literature, showing that they express novel classes of languages. Although many properties of classical languages hold ...

  20. Faster 2-regular information-set decoding

    NARCIS (Netherlands)

    Bernstein, D.J.; Lange, T.; Peters, C.P.; Schwabe, P.; Chee, Y.M.

    2011-01-01

    Fix positive integers B and w. Let C be a linear code over F 2 of length Bw. The 2-regular-decoding problem is to find a nonzero codeword consisting of w length-B blocks, each of which has Hamming weight 0 or 2. This problem appears in attacks on the FSB (fast syndrome-based) hash function and

  1. Complexity in union-free regular languages

    Czech Academy of Sciences Publication Activity Database

    Jirásková, G.; Masopust, Tomáš

    2011-01-01

    Roč. 22, č. 7 (2011), s. 1639-1653 ISSN 0129-0541 Institutional research plan: CEZ:AV0Z10190503 Keywords : Union-free regular language * one-cycle-free-path automaton * descriptional complexity Subject RIV: BA - General Mathematics Impact factor: 0.379, year: 2011 http://www.worldscinet.com/ijfcs/22/2207/S0129054111008933.html

  2. Regular Gleason Measures and Generalized Effect Algebras

    Science.gov (United States)

    Dvurečenskij, Anatolij; Janda, Jiří

    2015-12-01

    We study measures, finitely additive measures, regular measures, and σ-additive measures that can attain even infinite values on the quantum logic of a Hilbert space. We show when particular classes of non-negative measures can be studied in the frame of generalized effect algebras.

  3. Regularization of finite temperature string theories

    International Nuclear Information System (INIS)

    Leblanc, Y.; Knecht, M.; Wallet, J.C.

    1990-01-01

    The tachyonic divergences occurring in the free energy of various string theories at finite temperature are eliminated through the use of regularization schemes and analytic continuations. For closed strings, we obtain finite expressions which, however, develop an imaginary part above the Hagedorn temperature, whereas open string theories are still plagued with dilatonic divergences. (orig.)

  4. A Sim(2 invariant dimensional regularization

    Directory of Open Access Journals (Sweden)

    J. Alfaro

    2017-09-01

    Full Text Available We introduce a Sim(2 invariant dimensional regularization of loop integrals. Then we can compute the one loop quantum corrections to the photon self energy, electron self energy and vertex in the Electrodynamics sector of the Very Special Relativity Standard Model (VSRSM.

  5. Continuum regularized Yang-Mills theory

    International Nuclear Information System (INIS)

    Sadun, L.A.

    1987-01-01

    Using the machinery of stochastic quantization, Z. Bern, M. B. Halpern, C. Taubes and I recently proposed a continuum regularization technique for quantum field theory. This regularization may be implemented by applying a regulator to either the (d + 1)-dimensional Parisi-Wu Langevin equation or, equivalently, to the d-dimensional second order Schwinger-Dyson (SD) equations. This technique is non-perturbative, respects all gauge and Lorentz symmetries, and is consistent with a ghost-free gauge fixing (Zwanziger's). This thesis is a detailed study of this regulator, and of regularized Yang-Mills theory, using both perturbative and non-perturbative techniques. The perturbative analysis comes first. The mechanism of stochastic quantization is reviewed, and a perturbative expansion based on second-order SD equations is developed. A diagrammatic method (SD diagrams) for evaluating terms of this expansion is developed. We apply the continuum regulator to a scalar field theory. Using SD diagrams, we show that all Green functions can be rendered finite to all orders in perturbation theory. Even non-renormalizable theories can be regularized. The continuum regulator is then applied to Yang-Mills theory, in conjunction with Zwanziger's gauge fixing. A perturbative expansion of the regulator is incorporated into the diagrammatic method. It is hoped that the techniques discussed in this thesis will contribute to the construction of a renormalized Yang-Mills theory is 3 and 4 dimensions

  6. Gravitational lensing by a regular black hole

    International Nuclear Information System (INIS)

    Eiroa, Ernesto F; Sendra, Carlos M

    2011-01-01

    In this paper, we study a regular Bardeen black hole as a gravitational lens. We find the strong deflection limit for the deflection angle, from which we obtain the positions and magnifications of the relativistic images. As an example, we apply the results to the particular case of the supermassive black hole at the center of our galaxy.

  7. Gravitational lensing by a regular black hole

    Energy Technology Data Exchange (ETDEWEB)

    Eiroa, Ernesto F; Sendra, Carlos M, E-mail: eiroa@iafe.uba.ar, E-mail: cmsendra@iafe.uba.ar [Instituto de Astronomia y Fisica del Espacio, CC 67, Suc. 28, 1428, Buenos Aires (Argentina)

    2011-04-21

    In this paper, we study a regular Bardeen black hole as a gravitational lens. We find the strong deflection limit for the deflection angle, from which we obtain the positions and magnifications of the relativistic images. As an example, we apply the results to the particular case of the supermassive black hole at the center of our galaxy.

  8. Analytic stochastic regularization and gange invariance

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Lima-Santos, A.

    1986-05-01

    A proof that analytic stochastic regularization breaks gauge invariance is presented. This is done by an explicit one loop calculation of the vaccum polarization tensor in scalar electrodynamics, which turns out not to be transversal. The counterterm structure, Langevin equations and the construction of composite operators in the general framework of stochastic quantization, are also analysed. (Author) [pt

  9. Annotation of regular polysemy and underspecification

    DEFF Research Database (Denmark)

    Martínez Alonso, Héctor; Pedersen, Bolette Sandford; Bel, Núria

    2013-01-01

    We present the result of an annotation task on regular polysemy for a series of seman- tic classes or dot types in English, Dan- ish and Spanish. This article describes the annotation process, the results in terms of inter-encoder agreement, and the sense distributions obtained with two methods...

  10. Stabilization, pole placement, and regular implementability

    NARCIS (Netherlands)

    Belur, MN; Trentelman, HL

    In this paper, we study control by interconnection of linear differential systems. We give necessary and sufficient conditions for regular implementability of a-given linear, differential system. We formulate the problems of stabilization and pole placement as problems of finding a suitable,

  11. 12 CFR 725.3 - Regular membership.

    Science.gov (United States)

    2010-01-01

    ... UNION ADMINISTRATION CENTRAL LIQUIDITY FACILITY § 725.3 Regular membership. (a) A natural person credit....5(b) of this part, and forwarding with its completed application funds equal to one-half of this... 1, 1979, is not required to forward these funds to the Facility until October 1, 1979. (3...

  12. Supervised scale-regularized linear convolutionary filters

    DEFF Research Database (Denmark)

    Loog, Marco; Lauze, Francois Bernard

    2017-01-01

    also be solved relatively efficient. All in all, the idea is to properly control the scale of a trained filter, which we solve by introducing a specific regularization term into the overall objective function. We demonstrate, on an artificial filter learning problem, the capabil- ities of our basic...

  13. On regular riesz operators | Raubenheimer | Quaestiones ...

    African Journals Online (AJOL)

    The r-asymptotically quasi finite rank operators on Banach lattices are examples of regular Riesz operators. We characterise Riesz elements in a subalgebra of a Banach algebra in terms of Riesz elements in the Banach algebra. This enables us to characterise r-asymptotically quasi finite rank operators in terms of adjoint ...

  14. Regularized Discriminant Analysis: A Large Dimensional Study

    KAUST Repository

    Yang, Xiaoke

    2018-04-28

    In this thesis, we focus on studying the performance of general regularized discriminant analysis (RDA) classifiers. The data used for analysis is assumed to follow Gaussian mixture model with different means and covariances. RDA offers a rich class of regularization options, covering as special cases the regularized linear discriminant analysis (RLDA) and the regularized quadratic discriminant analysis (RQDA) classi ers. We analyze RDA under the double asymptotic regime where the data dimension and the training size both increase in a proportional way. This double asymptotic regime allows for application of fundamental results from random matrix theory. Under the double asymptotic regime and some mild assumptions, we show that the asymptotic classification error converges to a deterministic quantity that only depends on the data statistical parameters and dimensions. This result not only implicates some mathematical relations between the misclassification error and the class statistics, but also can be leveraged to select the optimal parameters that minimize the classification error, thus yielding the optimal classifier. Validation results on the synthetic data show a good accuracy of our theoretical findings. We also construct a general consistent estimator to approximate the true classification error in consideration of the unknown previous statistics. We benchmark the performance of our proposed consistent estimator against classical estimator on synthetic data. The observations demonstrate that the general estimator outperforms others in terms of mean squared error (MSE).

  15. Complexity in union-free regular languages

    Czech Academy of Sciences Publication Activity Database

    Jirásková, G.; Masopust, Tomáš

    2011-01-01

    Roč. 22, č. 7 (2011), s. 1639-1653 ISSN 0129-0541 Institutional research plan: CEZ:AV0Z10190503 Keywords : Union-free regular language * one-cycle-free- path automaton * descriptional complexity Subject RIV: BA - General Mathematics Impact factor: 0.379, year: 2011 http://www.worldscinet.com/ijfcs/22/2207/S0129054111008933.html

  16. Bit-coded regular expression parsing

    DEFF Research Database (Denmark)

    Nielsen, Lasse; Henglein, Fritz

    2011-01-01

    the DFA-based parsing algorithm due to Dub ´e and Feeley to emit the bits of the bit representation without explicitly materializing the parse tree itself. We furthermore show that Frisch and Cardelli’s greedy regular expression parsing algorithm can be straightforwardly modified to produce bit codings...

  17. Tetravalent one-regular graphs of order 4p2

    DEFF Research Database (Denmark)

    Feng, Yan-Quan; Kutnar, Klavdija; Marusic, Dragan

    2014-01-01

    A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified.......A graph is one-regular if its automorphism group acts regularly on the set of its arcs. In this paper tetravalent one-regular graphs of order 4p2, where p is a prime, are classified....

  18. Solar Photovoltaic

    OpenAIRE

    Wang, Chen; Lu, Yuefeng

    2016-01-01

    In the 21st century, human demand for new energy sources is urgent, because the traditional fossil energy is unable to meet human needs, and the fossil resource will make pollution, in this situation, solar energy gradually into the vision of scientists. As science advances, humans can already extensive use of solar energy to generate electricity. Solar energy is an inexhaustible and clean energy. In the global energy crisis, environmental pollution is the growing problem of today. The us...

  19. Solar magnetohydrodynamics

    International Nuclear Information System (INIS)

    Priest, E.R.

    1982-01-01

    The book serves several purposes. First set of chapters gives a concise general introduction to solar physics. In a second set the basic methods of magnetohydrodynamics are developed. A third set of chapters is an account of current theories for observed phenomena. The book is suitable for a course in solar physics and it also provides a comprehensive review of present magnetohydrodynamical models in solar physics. (SC)

  20. Solar constraints

    International Nuclear Information System (INIS)

    Provost, J.

    1984-01-01

    Accurate tests of the theory of stellar structure and evolution are available from the Sun's observations. The solar constraints are reviewed, with a special attention to the recent progress in observing global solar oscillations. Each constraint is sensitive to a given region of the Sun. The present solar models (standard, low Z, mixed) are discussed with respect to neutrino flux, low and high degree five-minute oscillations and low degree internal gravity modes. It appears that actually there do not exist solar models able to fully account for all the observed quantities. (Auth.)

  1. Solar Simulator

    Science.gov (United States)

    1981-01-01

    Oriel Corporation's simulators have a high pressure xenon lamp whose reflected light is processed by an optical system to produce a uniform solar beam. Because of many different types of applications, the simulators must be adjustable to replicate many different areas of the solar radiation spectrum. Simulators are laboratory tools for such purposes as testing and calibrating solar cells, or other solar energy systems, testing dyes, paints and pigments, pharmaceuticals and cosmetic preparations, plant and animal studies, food and agriculture studies and oceanographic research.

  2. A Remarkable Recent Transition in the Solar Dynamo

    NARCIS (Netherlands)

    de Jager, C.; Akasofu, S.-I.; Duhau, S.; Livingston, W.C.; Nieuwenhuijzen, H.; Potgieter, M.S.

    2016-01-01

    We summarize the major aspects of the remarkable, fairly long lasting period(∼ 2005 to ∼ 2010) of low solar activity, that we will call the Transition. It is the transitionalstage between the Grand Maximum of the 20th century and a forthcoming (most probablyRegular) episode of solar activity. The

  3. Occultism in an African context: a case for the Vhavenda-speaking people of the Limpopo Province

    Directory of Open Access Journals (Sweden)

    T. D. Mashau

    2007-07-01

    Full Text Available Occultism in Africa is as old as the primal religion itself, or what came to be known as African Traditional Religion (ATR in mo- dern times. It dates back to time immemorial. Occultism in Africa has taken various forms and has manifested in different ways over the ages, i.e. spiritism, divination, witchcraft and ma- gic. The underlying premise of African occultism is the belief in a spiritual world with spiritual forces that have power to inflict harm on the living. In the traditional African worldview suffering of every sort – illness, barrenness, drought and death – is nor- mally explained in personal terms: “there is always somebody”. This “somebody” often belongs to the world of the occult: a “spirit” has brought pain to human beings and must therefore be repelled or accommodated. This is very common among the Vhavenda-speaking people of the Limpopo Province. This ar- ticle seeks to investigate how occultism is practised among these people and to provide a reformed perspective as to how people who are suffering under demonic attacks can be helped. Contrary to other Christian traditions that see exorcism as the only way out, reformed theology suggests a missio-pastoral approach in dealing with the problem.

  4. Spatial patterns of whole brain grey and white matter injury in patients with occult spastic diplegic cerebral palsy.

    Science.gov (United States)

    Mu, Xuetao; Nie, Binbin; Wang, Hong; Duan, Shaofeng; Zhang, Zan; Dai, Guanghui; Ma, Qiaozhi; Shan, Baoci; Ma, Lin

    2014-01-01

    Spastic diplegic cerebral palsy (SDCP) is a common type of cerebral palsy (CP), which presents as a group of motor-impairment syndromes. Previous conventional MRI studies have reported abnormal structural changes in SDCP, such as periventricular leucomalacia. However, there are roughly 27.8% SDCP patients presenting normal appearance in conventional MRI, which were considered as occult SDCP. In this study, sixteen patients with occult SDCP and 16 age- and sex-matched healthy control subjects were collected and the data were acquired on a 3T MR system. We applied voxel-based morphometry (VBM) and tract-based spatial statistics (TBSS) analysis to investigate whole brain grey and white matter injury in occult SDCP. By using VBM method, the grey matter volume reduction was revealed in the bilateral basal ganglia regions, thalamus, insula, and left cerebral peduncle, whereas the white matter atrophy was found to be located in the posterior part of corpus callosum and right posterior corona radiata in the occult SDCP patients. By using TBSS, reduced fractional anisotropy (FA) values were detected in multiple white matter regions, including bilateral white matter tracts in prefrontal lobe, temporal lobe, internal and external capsule, corpus callosum, cingulum, thalamus, brainstem and cerebellum. Additionally, several regions of white matter tracts injury were found to be significantly correlated with motor dysfunction. These results collectively revealed the spatial patterns of whole brain grey and white matter injury in occult SDCP.

  5. Using Tikhonov Regularization for Spatial Projections from CSR Regularized Spherical Harmonic GRACE Solutions

    Science.gov (United States)

    Save, H.; Bettadpur, S. V.

    2013-12-01

    It has been demonstrated before that using Tikhonov regularization produces spherical harmonic solutions from GRACE that have very little residual stripes while capturing all the signal observed by GRACE within the noise level. This paper demonstrates a two-step process and uses Tikhonov regularization to remove the residual stripes in the CSR regularized spherical harmonic coefficients when computing the spatial projections. We discuss methods to produce mass anomaly grids that have no stripe features while satisfying the necessary condition of capturing all observed signal within the GRACE noise level.

  6. Uptake of a colorectal cancer screening blood test in people with elevated risk for cancer who cannot or will not complete a faecal occult blood test.

    Science.gov (United States)

    Symonds, Erin L; Cock, Charles; Meng, Rosie; Cole, Stephen R; Fraser, Robert J L; Young, Graeme P

    2017-03-31

    Participation rates in colorectal cancer (CRC) screening programmes using faecal occult blood tests (FOBTs) are low. Nonparticipation is commonly attributed to psychosocial factors, but some medical conditions also prevent screening. These barriers might be partially overcome if a blood test for CRC screening was available. This study determined whether people who had always declined screening by FOBT would participate if offered a blood test. An audit of registrants within a personalized CRC screening programme was undertaken to determine the reasons for regular nonparticipation in FOBT. Consistent nonparticipants (n=240) were randomly selected and invited for CRC screening with a blood test. Demographic characteristics and the reasons for prior FOBT nonparticipation were collected by means of a questionnaire. Nonparticipation in the screening programme could be classified as either behavioural (8.6%), with consistent noncompliance, or due to medical contraindications (8.5%), which included chronic rectal bleeding, being deemed unsuitable by a health professional, and needing personal assistance. Blood test uptake was 25%, with participation in the medical contraindications group greater than that in the behavioural group (43 vs. 12%, Pprocrastination and dislike of the test, but these were not associated with blood test uptake (P>0.05). There is a subgroup of the community who have medical reasons for nonparticipation in CRC screening with FOBT but will participate if offered a blood test. The option of a blood test does not, however, improve uptake in those who admit to behavioural reasons for noncompliance with screening.

  7. Extreme values, regular variation and point processes

    CERN Document Server

    Resnick, Sidney I

    1987-01-01

    Extremes Values, Regular Variation and Point Processes is a readable and efficient account of the fundamental mathematical and stochastic process techniques needed to study the behavior of extreme values of phenomena based on independent and identically distributed random variables and vectors It presents a coherent treatment of the distributional and sample path fundamental properties of extremes and records It emphasizes the core primacy of three topics necessary for understanding extremes the analytical theory of regularly varying functions; the probabilistic theory of point processes and random measures; and the link to asymptotic distribution approximations provided by the theory of weak convergence of probability measures in metric spaces The book is self-contained and requires an introductory measure-theoretic course in probability as a prerequisite Almost all sections have an extensive list of exercises which extend developments in the text, offer alternate approaches, test mastery and provide for enj...

  8. Stream Processing Using Grammars and Regular Expressions

    DEFF Research Database (Denmark)

    Rasmussen, Ulrik Terp

    disambiguation. The first algorithm operates in two passes in a semi-streaming fashion, using a constant amount of working memory and an auxiliary tape storage which is written in the first pass and consumed by the second. The second algorithm is a single-pass and optimally streaming algorithm which outputs...... as much of the parse tree as is semantically possible based on the input prefix read so far, and resorts to buffering as many symbols as is required to resolve the next choice. Optimality is obtained by performing a PSPACE-complete pre-analysis on the regular expression. In the second part we present...... Kleenex, a language for expressing high-performance streaming string processing programs as regular grammars with embedded semantic actions, and its compilation to streaming string transducers with worst-case linear-time performance. Its underlying theory is based on transducer decomposition into oracle...

  9. Describing chaotic attractors: Regular and perpetual points

    Science.gov (United States)

    Dudkowski, Dawid; Prasad, Awadhesh; Kapitaniak, Tomasz

    2018-03-01

    We study the concepts of regular and perpetual points for describing the behavior of chaotic attractors in dynamical systems. The idea of these points, which have been recently introduced to theoretical investigations, is thoroughly discussed and extended into new types of models. We analyze the correlation between regular and perpetual points, as well as their relation with phase space, showing the potential usefulness of both types of points in the qualitative description of co-existing states. The ability of perpetual points in finding attractors is indicated, along with its potential cause. The location of chaotic trajectories and sets of considered points is investigated and the study on the stability of systems is shown. The statistical analysis of the observing desired states is performed. We focus on various types of dynamical systems, i.e., chaotic flows with self-excited and hidden attractors, forced mechanical models, and semiconductor superlattices, exhibiting the universality of appearance of the observed patterns and relations.

  10. Chaos regularization of quantum tunneling rates

    International Nuclear Information System (INIS)

    Pecora, Louis M.; Wu Dongho; Lee, Hoshik; Antonsen, Thomas; Lee, Ming-Jer; Ott, Edward

    2011-01-01

    Quantum tunneling rates through a barrier separating two-dimensional, symmetric, double-well potentials are shown to depend on the classical dynamics of the billiard trajectories in each well and, hence, on the shape of the wells. For shapes that lead to regular (integrable) classical dynamics the tunneling rates fluctuate greatly with eigenenergies of the states sometimes by over two orders of magnitude. Contrarily, shapes that lead to completely chaotic trajectories lead to tunneling rates whose fluctuations are greatly reduced, a phenomenon we call regularization of tunneling rates. We show that a random-plane-wave theory of tunneling accounts for the mean tunneling rates and the small fluctuation variances for the chaotic systems.

  11. Least square regularized regression in sum space.

    Science.gov (United States)

    Xu, Yong-Li; Chen, Di-Rong; Li, Han-Xiong; Liu, Lu

    2013-04-01

    This paper proposes a least square regularized regression algorithm in sum space of reproducing kernel Hilbert spaces (RKHSs) for nonflat function approximation, and obtains the solution of the algorithm by solving a system of linear equations. This algorithm can approximate the low- and high-frequency component of the target function with large and small scale kernels, respectively. The convergence and learning rate are analyzed. We measure the complexity of the sum space by its covering number and demonstrate that the covering number can be bounded by the product of the covering numbers of basic RKHSs. For sum space of RKHSs with Gaussian kernels, by choosing appropriate parameters, we tradeoff the sample error and regularization error, and obtain a polynomial learning rate, which is better than that in any single RKHS. The utility of this method is illustrated with two simulated data sets and five real-life databases.

  12. Contour Propagation With Riemannian Elasticity Regularization

    DEFF Research Database (Denmark)

    Bjerre, Troels; Hansen, Mads Fogtmann; Sapru, W.

    2011-01-01

    Purpose/Objective(s): Adaptive techniques allow for correction of spatial changes during the time course of the fractionated radiotherapy. Spatial changes include tumor shrinkage and weight loss, causing tissue deformation and residual positional errors even after translational and rotational image...... the planning CT onto the rescans and correcting to reflect actual anatomical changes. For deformable registration, a free-form, multi-level, B-spline deformation model with Riemannian elasticity, penalizing non-rigid local deformations, and volumetric changes, was used. Regularization parameters was defined...... on the original delineation and tissue deformation in the time course between scans form a better starting point than rigid propagation. There was no significant difference of locally and globally defined regularization. The method used in the present study suggests that deformed contours need to be reviewed...

  13. Thin accretion disk around regular black hole

    Directory of Open Access Journals (Sweden)

    QIU Tianqi

    2014-08-01

    Full Text Available The Penrose′s cosmic censorship conjecture says that naked singularities do not exist in nature.So,it seems reasonable to further conjecture that not even a singularity exists in nature.In this paper,a regular black hole without singularity is studied in detail,especially on its thin accretion disk,energy flux,radiation temperature and accretion efficiency.It is found that the interaction of regular black hole is stronger than that of the Schwarzschild black hole. Furthermore,the thin accretion will be more efficiency to lost energy while the mass of black hole decreased. These particular properties may be used to distinguish between black holes.

  14. Convex nonnegative matrix factorization with manifold regularization.

    Science.gov (United States)

    Hu, Wenjun; Choi, Kup-Sze; Wang, Peiliang; Jiang, Yunliang; Wang, Shitong

    2015-03-01

    Nonnegative Matrix Factorization (NMF) has been extensively applied in many areas, including computer vision, pattern recognition, text mining, and signal processing. However, nonnegative entries are usually required for the data matrix in NMF, which limits its application. Besides, while the basis and encoding vectors obtained by NMF can represent the original data in low dimension, the representations do not always reflect the intrinsic geometric structure embedded in the data. Motivated by manifold learning and Convex NMF (CNMF), we propose a novel matrix factorization method called Graph Regularized and Convex Nonnegative Matrix Factorization (GCNMF) by introducing a graph regularized term into CNMF. The proposed matrix factorization technique not only inherits the intrinsic low-dimensional manifold structure, but also allows the processing of mixed-sign data matrix. Clustering experiments on nonnegative and mixed-sign real-world data sets are conducted to demonstrate the effectiveness of the proposed method. Copyright © 2014 Elsevier Ltd. All rights reserved.

  15. Solar cooking

    Science.gov (United States)

    Over two billion people face fuel wood shortages, causing tremendous personal and environmental stress. Over 4 million people die prematurely from indoor air pollution. Solar cooking can reduce fuel wood consumption and indoor air pollution. Solar cooking has been practiced and published since th...

  16. Solar Sprint

    Science.gov (United States)

    Tabor, Richard; Anderson, Stephen

    2007-01-01

    In the "Solar Sprint" activity, students design, test, and race a solar-powered car built with Legos. The use of ratios is incorporated to simulate the actual work of scientists and engineers. This method encourages fourth-grade students to think about multiple variables and stimulates their curiosity when an activity doesn't come out as…

  17. A short proof of increased parabolic regularity

    Directory of Open Access Journals (Sweden)

    Stephen Pankavich

    2015-08-01

    Full Text Available We present a short proof of the increased regularity obtained by solutions to uniformly parabolic partial differential equations. Though this setting is fairly introductory, our new method of proof, which uses a priori estimates and an inductive method, can be extended to prove analogous results for problems with time-dependent coefficients, advection-diffusion or reaction diffusion equations, and nonlinear PDEs even when other tools, such as semigroup methods or the use of explicit fundamental solutions, are unavailable.

  18. Regular black hole in three dimensions

    OpenAIRE

    Myung, Yun Soo; Yoon, Myungseok

    2008-01-01

    We find a new black hole in three dimensional anti-de Sitter space by introducing an anisotropic perfect fluid inspired by the noncommutative black hole. This is a regular black hole with two horizons. We compare thermodynamics of this black hole with that of non-rotating BTZ black hole. The first-law of thermodynamics is not compatible with the Bekenstein-Hawking entropy.

  19. Sparse regularization for force identification using dictionaries

    Science.gov (United States)

    Qiao, Baijie; Zhang, Xingwu; Wang, Chenxi; Zhang, Hang; Chen, Xuefeng

    2016-04-01

    The classical function expansion method based on minimizing l2-norm of the response residual employs various basis functions to represent the unknown force. Its difficulty lies in determining the optimum number of basis functions. Considering the sparsity of force in the time domain or in other basis space, we develop a general sparse regularization method based on minimizing l1-norm of the coefficient vector of basis functions. The number of basis functions is adaptively determined by minimizing the number of nonzero components in the coefficient vector during the sparse regularization process. First, according to the profile of the unknown force, the dictionary composed of basis functions is determined. Second, a sparsity convex optimization model for force identification is constructed. Third, given the transfer function and the operational response, Sparse reconstruction by separable approximation (SpaRSA) is developed to solve the sparse regularization problem of force identification. Finally, experiments including identification of impact and harmonic forces are conducted on a cantilever thin plate structure to illustrate the effectiveness and applicability of SpaRSA. Besides the Dirac dictionary, other three sparse dictionaries including Db6 wavelets, Sym4 wavelets and cubic B-spline functions can also accurately identify both the single and double impact forces from highly noisy responses in a sparse representation frame. The discrete cosine functions can also successfully reconstruct the harmonic forces including the sinusoidal, square and triangular forces. Conversely, the traditional Tikhonov regularization method with the L-curve criterion fails to identify both the impact and harmonic forces in these cases.

  20. Analytic stochastic regularization and gauge theories

    International Nuclear Information System (INIS)

    Abdalla, E.; Gomes, M.; Lima-Santos, A.

    1987-04-01

    We prove that analytic stochatic regularization braks gauge invariance. This is done by an explicit one loop calculation of the two three and four point vertex functions of the gluon field in scalar chromodynamics, which turns out not to be geuge invariant. We analyse the counter term structure, Langevin equations and the construction of composite operators in the general framework of stochastic quantization. (author) [pt

  1. Preconditioners for regularized saddle point matrices

    Czech Academy of Sciences Publication Activity Database

    Axelsson, Owe

    2011-01-01

    Roč. 19, č. 2 (2011), s. 91-112 ISSN 1570-2820 Institutional research plan: CEZ:AV0Z30860518 Keywords : saddle point matrices * preconditioning * regularization * eigenvalue clustering Subject RIV: BA - General Mathematics Impact factor: 0.533, year: 2011 http://www.degruyter.com/view/j/jnma.2011.19.issue-2/jnum.2011.005/jnum.2011.005. xml

  2. Analytic stochastic regularization: gauge and supersymmetry theories

    International Nuclear Information System (INIS)

    Abdalla, M.C.B.

    1988-01-01

    Analytic stochastic regularization for gauge and supersymmetric theories is considered. Gauge invariance in spinor and scalar QCD is verified to brak fown by an explicit one loop computation of the two, theree and four point vertex function of the gluon field. As a result, non gauge invariant counterterms must be added. However, in the supersymmetric multiplets there is a cancellation rendering the counterterms gauge invariant. The calculation is considered at one loop order. (author) [pt

  3. Regularized forecasting of chaotic dynamical systems

    International Nuclear Information System (INIS)

    Bollt, Erik M.

    2017-01-01

    While local models of dynamical systems have been highly successful in terms of using extensive data sets observing even a chaotic dynamical system to produce useful forecasts, there is a typical problem as follows. Specifically, with k-near neighbors, kNN method, local observations occur due to recurrences in a chaotic system, and this allows for local models to be built by regression to low dimensional polynomial approximations of the underlying system estimating a Taylor series. This has been a popular approach, particularly in context of scalar data observations which have been represented by time-delay embedding methods. However such local models can generally allow for spatial discontinuities of forecasts when considered globally, meaning jumps in predictions because the collected near neighbors vary from point to point. The source of these discontinuities is generally that the set of near neighbors varies discontinuously with respect to the position of the sample point, and so therefore does the model built from the near neighbors. It is possible to utilize local information inferred from near neighbors as usual but at the same time to impose a degree of regularity on a global scale. We present here a new global perspective extending the general local modeling concept. In so doing, then we proceed to show how this perspective allows us to impose prior presumed regularity into the model, by involving the Tikhonov regularity theory, since this classic perspective of optimization in ill-posed problems naturally balances fitting an objective with some prior assumed form of the result, such as continuity or derivative regularity for example. This all reduces to matrix manipulations which we demonstrate on a simple data set, with the implication that it may find much broader context.

  4. Minimal length uncertainty relation and ultraviolet regularization

    Science.gov (United States)

    Kempf, Achim; Mangano, Gianpiero

    1997-06-01

    Studies in string theory and quantum gravity suggest the existence of a finite lower limit Δx0 to the possible resolution of distances, at the latest on the scale of the Planck length of 10-35 m. Within the framework of the Euclidean path integral we explicitly show ultraviolet regularization in field theory through this short distance structure. Both rotation and translation invariance can be preserved. An example is studied in detail.

  5. Rotation of the Solar Equator

    Science.gov (United States)

    Kotov, V. A.

    2017-06-01

    Regular measurements of the general magnetic field of the Sun, performed over about half a century at the Crimean Astrophysical Observatory, the J. Wilcox Solar Observatory, and five other observatories, are considered in detail for the time 1968 - 2016. They include more than twenty-six thousand daily values of the mean line-of-sight field strength of the visible solar hemisphere. On the basis of these values, the equatorial rotation period of the Sun is found to be 26.926(9) d (synodic). It is shown that its half-value coincides within error limits with both the main period of the magnetic four-sector structure, 13.4577(25) d, and the best-commensurate period of the slow motions of the major solar system bodies, 13.479(22) d (sidereal). The probability that the two periods coincide by chance is estimated to be about 10^{-7}. The true origin of this odd resonance is unknown.

  6. Regularity and chaos in cavity QED

    International Nuclear Information System (INIS)

    Bastarrachea-Magnani, Miguel Angel; López-del-Carpio, Baldemar; Chávez-Carlos, Jorge; Lerma-Hernández, Sergio; Hirsch, Jorge G

    2017-01-01

    The interaction of a quantized electromagnetic field in a cavity with a set of two-level atoms inside it can be described with algebraic Hamiltonians of increasing complexity, from the Rabi to the Dicke models. Their algebraic character allows, through the use of coherent states, a semiclassical description in phase space, where the non-integrable Dicke model has regions associated with regular and chaotic motion. The appearance of classical chaos can be quantified calculating the largest Lyapunov exponent over the whole available phase space for a given energy. In the quantum regime, employing efficient diagonalization techniques, we are able to perform a detailed quantitative study of the regular and chaotic regions, where the quantum participation ratio (P R ) of coherent states on the eigenenergy basis plays a role equivalent to the Lyapunov exponent. It is noted that, in the thermodynamic limit, dividing the participation ratio by the number of atoms leads to a positive value in chaotic regions, while it tends to zero in the regular ones. (paper)

  7. Solution path for manifold regularized semisupervised classification.

    Science.gov (United States)

    Wang, Gang; Wang, Fei; Chen, Tao; Yeung, Dit-Yan; Lochovsky, Frederick H

    2012-04-01

    Traditional learning algorithms use only labeled data for training. However, labeled examples are often difficult or time consuming to obtain since they require substantial human labeling efforts. On the other hand, unlabeled data are often relatively easy to collect. Semisupervised learning addresses this problem by using large quantities of unlabeled data with labeled data to build better learning algorithms. In this paper, we use the manifold regularization approach to formulate the semisupervised learning problem where a regularization framework which balances a tradeoff between loss and penalty is established. We investigate different implementations of the loss function and identify the methods which have the least computational expense. The regularization hyperparameter, which determines the balance between loss and penalty, is crucial to model selection. Accordingly, we derive an algorithm that can fit the entire path of solutions for every value of the hyperparameter. Its computational complexity after preprocessing is quadratic only in the number of labeled examples rather than the total number of labeled and unlabeled examples.

  8. Regularizations: different recipes for identical situations

    International Nuclear Information System (INIS)

    Gambin, E.; Lobo, C.O.; Battistel, O.A.

    2004-03-01

    We present a discussion where the choice of the regularization procedure and the routing for the internal lines momenta are put at the same level of arbitrariness in the analysis of Ward identities involving simple and well-known problems in QFT. They are the complex self-interacting scalar field and two simple models where the SVV and AVV process are pertinent. We show that, in all these problems, the conditions to symmetry relations preservation are put in terms of the same combination of divergent Feynman integrals, which are evaluated in the context of a very general calculational strategy, concerning the manipulations and calculations involving divergences. Within the adopted strategy, all the arbitrariness intrinsic to the problem are still maintained in the final results and, consequently, a perfect map can be obtained with the corresponding results of the traditional regularization techniques. We show that, when we require an universal interpretation for the arbitrariness involved, in order to get consistency with all stated physical constraints, a strong condition is imposed for regularizations which automatically eliminates the ambiguities associated to the routing of the internal lines momenta of loops. The conclusion is clean and sound: the association between ambiguities and unavoidable symmetry violations in Ward identities cannot be maintained if an unique recipe is required for identical situations in the evaluation of divergent physical amplitudes. (author)

  9. Clinical features of secondary glaucoma caused by lens suspensory ligament laxity or occult subluxation

    Directory of Open Access Journals (Sweden)

    Yi Ma

    2018-04-01

    Full Text Available AIM: To investigate the clinical characteristics of secondary glaucoma caused by lens suspensory ligament laxity or occult subluxation, and to analyze the influence of operation on visual acuity and intraocular pressure(IOP. METHODS: Totally 38 cases(38 eyesof the secondary glaucoma caused by lens suspensory ligament laxity or occult subluxation in ophthalmology department of our hospital from December 2014 to December 2016 were enrolled and their medical records were analyzed retrospectively to observe the clinical characteristics of glaucoma. Preoperative mydriasis was carried out and surgical methods were chosen according to the lenses location and extent of suspensory ligament. Preoperative and postoperative anterior chamber depth, corneal endothelial cell density, IOP, visual field, visual acuity and complications were analyzed. RESULTS: The average intraocular pressure was 18.17±1.43mmHg at postoperatively 10d, which was significantly lower than 38.77±2.45mmHg before operation, the difference had statistical significance(PP>0.05. The postoperative anterior chamber depth was 2.45±0.44mm, which was significantly higher than 1.23±0.35mm before operation, the difference had statistical significance(P2 and decreased significantly, compared with 1735.32±340.32/mm2 before operation, the difference had statistical significance(PCONCLUSION: Clinical symptoms and signs of secondary glaucoma in patients with lens suspensory ligament laxity or occult subluxation are more complex, which needs to be distinguished with other types of glaucoma in clinical treatment, and its surgical methods shall be chosen according to different suspensory ligament site and lens subluxation scope.

  10. Prognosis for Mammographically Occult, Early-Stage Breast Cancer Patients Treated With Breast-Conservation Therapy

    International Nuclear Information System (INIS)

    Yang, Tzu-I. J.; Yang Qifeng; Haffty, Bruce G.; Moran, Meena S.

    2010-01-01

    Purpose: To compare mammographically occult (MamOcc) and mammographically positive (MamPos) early-stage breast cancer patients treated with breast-conservation therapy (BCT), to analyze differences between the two cohorts. Methods and Materials: Our two cohorts consisted of 214 MamOcc and 2168 MamPos patients treated with BCT. Chart reviews were conducted to assess mammogram reports and method of detection. All clinical-pathologic and outcome parameters were analyzed to detect differences between the two cohorts. Results: Median follow-up was 7 years. There were no differences in final margins, T stage, nodal status, estrogen/progesterone receptor status, or 'triple-negative' status. Significant differences included younger age at diagnosis (p o histology (p < 0.0001). At 10 years, the differences in overall survival, cause-specific survival, and distant relapse between the two groups did not differ significantly. The MamOcc cohort had more breast relapses (15% vs. 8%; p = 0.0357), but on multivariate analysis this difference was not significant (hazard ratio 1.0, 95% confidence interval 0.993-1.007, p = 0.9296). Breast relapses were mammographically occult in 32% of the MamOcc and 12% of the MamPos cohorts (p = 0.0136). Conclusions: Although our study suggests that there are clinical-pathologic variations for the MamOcc cohort vs. MamPos patients that may ultimately affect management, breast relapse after BCT was not significantly different. Breast recurrences were more often mammographically occult in the MamOcc cohort; consideration should be given to closer follow-up and alternative imaging strategies (ultrasound, breast MRI) for routine posttreatment examination. To our knowledge, this represents the largest series addressing the prognostic significance of MamOcc cancers treated with BCT.

  11. Ionospheric Remote Sensing using GPS Radio Occultation and Ultraviolet Photometry aboard the ISS

    Science.gov (United States)

    Budzien, S. A.; Powell, S. P.; O'Hanlon, B.; Humphreys, T.; Bishop, R. L.; Stephan, A. W.; Gross, J.; Chakrabarti, S.

    2017-12-01

    The GPS Radio Occultation and Ultraviolet Photometer Co-located (GROUP-C) experiment launched to the International Space Station (ISS) on February 19, 2017 as part of the Space Test Program Houston #5 payload (STP-H5). After early orbit testing, GROUP-C began routine science operations in late April. GROUP-C includes a high-sensitivity far-ultraviolet photometer measuring horizontal nighttime ionospheric gradients and an advanced software-defined GPS receiver providing ionospheric electron density profiles, scintillation measurements, and lower atmosphere profiles. GROUP-C and a companion experiment, the Limb-Imaging Ionospheric and Thermospheric Extreme-Ultraviolet Spectrograph (LITES), offer a unique capability to study spatial and temporal variability of the thermosphere and ionosphere using multi-sensor approaches, including ionospheric tomography. Data are collected continuously across low- and mid-latitudes as the ISS orbit precesses through all local times every 60 days. The GROUP-C GPS sensor routinely collects dual-frequency GPS occultations, makes targeted raw signal captures of GPS and Galileo occultations, and includes multiple antennas to characterize multipath in the ISS environment. The UV photometer measures the 135.6 nm ionospheric recombination airglow emision along the nightside orbital track. We present the first analysis of ionospheric observations, discuss the challenges and opportunities of remote sensing from the ISS platform, and explore how these new data help address questions regarding the complex and dynamic features of the low and middle latitude ionosphere-thermosphere relevant to the upcoming GOLD and ICON missions.

  12. Detection of occult vertebral fractures by quantitative assessment of bone marrow attenuation values at MDCT

    International Nuclear Information System (INIS)

    Henes, Frank Oliver; Groth, Michael; Kramer, Harald; Schaefer, Christian; Regier, Marc; Derlin, Thorsten; Adam, Gerhard; Bannas, Peter

    2014-01-01

    Objectives: To determine a cut-off value of Hounsfield attenuation units (HU) at multidetector computed tomography (MDCT) for valid and reliable detection of bone marrow oedema (BME) related to occult vertebral fractures. Methods: 36 patients underwent both MDCT and Magnetic Resonance Imaging (MRI) for evaluation of vertebral fractures of the thoracolumbar spine and were included in this retrospective study. Two readers independently assessed HU values at MDCT in a total of 196 vertebrae. Reliability was assessed by intraclass correlation coefficient and Bland–Altman analysis. For each patient we determined the vertebra with the lowest HU value and calculated the HU-difference to each other vertebral body. HU-differences were subjected to receiver operating characteristic (ROC) curve analysis to determine the diagnostic accuracy for detection of BME as determined by MRI, which served as the reference standard. Results of HU-measurements were compared with standard visual evaluation of MDCT. Results: HU measurements demonstrated a high interrater reliability (ICC = 0.984). ROC curve analysis (AUC = 0.978) exhibited an ideal cut-off value of 29.6 HU for detection of BME associated with vertebral fractures with an accuracy of 97.4% as compared to 93.4% accuracy of visual evaluation. Particularly, HU-measurements increased the sensitivity for detection of vertebral fractures from 78.0% to 92.7% due to the detection of 7 of 9 occult fractures that were missed by visual evaluation alone. Conclusions: Assessing bone marrow density by HU measurements using the cut-off of 29.6 HU is a valid and reliable tool for detection of BME related to occult vertebral fractures in MDCT. The introduced technique may allow more accurate treatment decisions and may make further diagnostic work-up with MRI unnecessary

  13. Detection of occult vertebral fractures by quantitative assessment of bone marrow attenuation values at MDCT

    Energy Technology Data Exchange (ETDEWEB)

    Henes, Frank Oliver, E-mail: f.henes@uke.de [Department of Diagnostic and Interventional Radiology, Center for Radiology and Endoscopy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Groth, Michael [Department of Diagnostic and Interventional Neuroradiology, Center for Radiology and Endoscopy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany); Kramer, Harald [Department of Clinical Radiology, Ludwig-Maximilians-University Hospital Munich, Marchioninistr. 15, 81377 Munich (Germany); Department of Radiology, University of Wisconsin – Madison, Clinical Science Center, 600 Highland Avenue, Madison, WI 53792 (United States); Schaefer, Christian [Department of Trauma-, Hand- and Reconstructive Surgery, Spine Center, Center for Surgical Sciences, University Medical Center Hamburg-Eppendorf, Martinistraße 52, 20246 Hamburg (Germany); Regier, Marc; Derlin, Thorsten; Adam, Gerhard; Bannas, Peter [Department of Diagnostic and Interventional Radiology, Center for Radiology and Endoscopy, University Medical Center Hamburg-Eppendorf, Martinistr. 52, 20246 Hamburg (Germany)

    2014-01-15

    Objectives: To determine a cut-off value of Hounsfield attenuation units (HU) at multidetector computed tomography (MDCT) for valid and reliable detection of bone marrow oedema (BME) related to occult vertebral fractures. Methods: 36 patients underwent both MDCT and Magnetic Resonance Imaging (MRI) for evaluation of vertebral fractures of the thoracolumbar spine and were included in this retrospective study. Two readers independently assessed HU values at MDCT in a total of 196 vertebrae. Reliability was assessed by intraclass correlation coefficient and Bland–Altman analysis. For each patient we determined the vertebra with the lowest HU value and calculated the HU-difference to each other vertebral body. HU-differences were subjected to receiver operating characteristic (ROC) curve analysis to determine the diagnostic accuracy for detection of BME as determined by MRI, which served as the reference standard. Results of HU-measurements were compared with standard visual evaluation of MDCT. Results: HU measurements demonstrated a high interrater reliability (ICC = 0.984). ROC curve analysis (AUC = 0.978) exhibited an ideal cut-off value of 29.6 HU for detection of BME associated with vertebral fractures with an accuracy of 97.4% as compared to 93.4% accuracy of visual evaluation. Particularly, HU-measurements increased the sensitivity for detection of vertebral fractures from 78.0% to 92.7% due to the detection of 7 of 9 occult fractures that were missed by visual evaluation alone. Conclusions: Assessing bone marrow density by HU measurements using the cut-off of 29.6 HU is a valid and reliable tool for detection of BME related to occult vertebral fractures in MDCT. The introduced technique may allow more accurate treatment decisions and may make further diagnostic work-up with MRI unnecessary.

  14. Occult progression by Apc-deficient intestinal crypts as a target for chemoprevention

    Science.gov (United States)

    Liskay, R.Michael

    2014-01-01

    Although Apc mutation is widely considered an initiating event in colorectal cancer, little is known about the earliest stages of tumorigenesis following sporadic Apc loss. Therefore, we have utilized a novel mouse model that facilitates the sporadic inactivation of Apc via frameshift reversion of Cre in single, isolated cells and subsequently tracks the fates of Apc-deficient intestinal cells. Our results suggest that consistent with Apc being a ‘gatekeeper’, loss of Apc early in life during intestinal growth leads to adenomas or increased crypt fission, manifested by fields of mutant but otherwise normal-appearing crypts. In contrast, Apc loss occurring later in life has minimal consequences, with mutant crypts being less prone to either increased crypt fission or adenoma formation. Using the stem cell-specific Lgr5-CreER mouse, we generated different sized fields of Apc-deficient crypts via independent recombination events and found that field size correlates with progression to adenoma. To evaluate this early stage prior to adenoma formation as a therapeutic target, we examined the chemopreventive effects of sulindac on Apc-deficient occult crypt fission. We found that sulindac treatment started early in life inhibits the morphologically occult spread of Apc-deficient crypts and thus reduces adenoma numbers. Taken together these results suggest that: (i) earlier Apc loss promotes increased crypt fission, (ii) a field of Apc-deficient crypts, which can form via occult crypt fission or independent neighboring events, is an important intermediate between loss of Apc and adenoma formation and (iii) normal-appearing Apc-deficient crypts are potential unappreciated targets for cancer screening and chemoprevention. PMID:23996931

  15. Prediction of Occult Invasive Disease in Ductal Carcinoma in Situ Using Deep Learning Features.

    Science.gov (United States)

    Shi, Bibo; Grimm, Lars J; Mazurowski, Maciej A; Baker, Jay A; Marks, Jeffrey R; King, Lorraine M; Maley, Carlo C; Hwang, E Shelley; Lo, Joseph Y

    2018-03-01

    The aim of this study was to determine whether deep features extracted from digital mammograms using a pretrained deep convolutional neural network are prognostic of occult invasive disease for patients with ductal carcinoma in situ (DCIS) on core needle biopsy. In this retrospective study, digital mammographic magnification views were collected for 99 subjects with DCIS at biopsy, 25 of which were subsequently upstaged to invasive cancer. A deep convolutional neural network model that was pretrained on nonmedical images (eg, animals, plants, instruments) was used as the feature extractor. Through a statistical pooling strategy, deep features were extracted at different levels of convolutional layers from the lesion areas, without sacrificing the original resolution or distorting the underlying topology. A multivariate classifier was then trained to predict which tumors contain occult invasive disease. This was compared with the performance of traditional "handcrafted" computer vision (CV) features previously developed specifically to assess mammographic calcifications. The generalization performance was assessed using Monte Carlo cross-validation and receiver operating characteristic curve analysis. Deep features were able to distinguish DCIS with occult invasion from pure DCIS, with an area under the receiver operating characteristic curve of 0.70 (95% confidence interval, 0.68-0.73). This performance was comparable with the handcrafted CV features (area under the curve = 0.68; 95% confidence interval, 0.66-0.71) that were designed with prior domain knowledge. Despite being pretrained on only nonmedical images, the deep features extracted from digital mammograms demonstrated comparable performance with handcrafted CV features for the challenging task of predicting DCIS upstaging. Copyright © 2017 American College of Radiology. Published by Elsevier Inc. All rights reserved.

  16. The size, shape, density and ring of the dwarf planet Haumea from a stellar occultation.

    Science.gov (United States)

    Ortiz, J L; Santos-Sanz, P; Sicardy, B; Benedetti-Rossi, G; Bérard, D; Morales, N; Duffard, R; Braga-Ribas, F; Hopp, U; Ries, C; Nascimbeni, V; Marzari, F; Granata, V; Pál, A; Kiss, C; Pribulla, T; Komžík, R; Hornoch, K; Pravec, P; Bacci, P; Maestripieri, M; Nerli, L; Mazzei, L; Bachini, M; Martinelli, F; Succi, G; Ciabattari, F; Mikuz, H; Carbognani, A; Gaehrken, B; Mottola, S; Hellmich, S; Rommel, F L; Fernández-Valenzuela, E; Bagatin, A Campo; Cikota, S; Cikota, A; Lecacheux, J; Vieira-Martins, R; Camargo, J I B; Assafin, M; Colas, F; Behrend, R; Desmars, J; Meza, E; Alvarez-Candal, A; Beisker, W; Gomes-Junior, A R; Morgado, B E; Roques, F; Vachier, F; Berthier, J; Mueller, T G; Madiedo, J M; Unsalan, O; Sonbas, E; Karaman, N; Erece, O; Koseoglu, D T; Ozisik, T; Kalkan, S; Guney, Y; Niaei, M S; Satir, O; Yesilyaprak, C; Puskullu, C; Kabas, A; Demircan, O; Alikakos, J; Charmandaris, V; Leto, G; Ohlert, J; Christille, J M; Szakáts, R; Farkas, A Takácsné; Varga-Verebélyi, E; Marton, G; Marciniak, A; Bartczak, P; Santana-Ros, T; Butkiewicz-Bąk, M; Dudziński, G; Alí-Lagoa, V; Gazeas, K; Tzouganatos, L; Paschalis, N; Tsamis, V; Sánchez-Lavega, A; Pérez-Hoyos, S; Hueso, R; Guirado, J C; Peris, V; Iglesias-Marzoa, R

    2017-10-11

    Haumea-one of the four known trans-Neptunian dwarf planets-is a very elongated and rapidly rotating body. In contrast to other dwarf planets, its size, shape, albedo and density are not well constrained. The Centaur Chariklo was the first body other than a giant planet known to have a ring system, and the Centaur Chiron was later found to possess something similar to Chariklo's rings. Here we report observations from multiple Earth-based observatories of Haumea passing in front of a distant star (a multi-chord stellar occultation). Secondary events observed around the main body of Haumea are consistent with the presence of a ring with an opacity of 0.5, width of 70 kilometres and radius of about 2,287 kilometres. The ring is coplanar with both Haumea's equator and the orbit of its satellite Hi'iaka. The radius of the ring places it close to the 3:1 mean-motion resonance with Haumea's spin period-that is, Haumea rotates three times on its axis in the time that a ring particle completes one revolution. The occultation by the main body provides an instantaneous elliptical projected shape with axes of about 1,704 kilometres and 1,138 kilometres. Combined with rotational light curves, the occultation constrains the three-dimensional orientation of Haumea and its triaxial shape, which is inconsistent with a homogeneous body in hydrostatic equilibrium. Haumea's largest axis is at least 2,322 kilometres, larger than previously thought, implying an upper limit for its density of 1,885 kilograms per cubic metre and a geometric albedo of 0.51, both smaller than previous estimates. In addition, this estimate of the density of Haumea is closer to that of Pluto than are previous estimates, in line with expectations. No global nitrogen- or methane-dominated atmosphere was detected.

  17. Radioguided breast surgery for occult lesion localization – correlation between two methods

    Directory of Open Access Journals (Sweden)

    Gutfilen Bianca

    2008-08-01

    Full Text Available Abstract Background The detection of sub-clinical breast lesions has increased with screening mammography. Biopsy techniques can offer precision and agility in its execution, as well as patient comfort. This trial compares radioguided occult lesion localization (ROLL and wire-guided localization (WL of breast lesions. We investigate if a procedure at the ambulatorial level (ROLL could lead to a better aesthetic result and less postoperative pain. In addition, we intend to demonstrate the efficacy of radioguided localization and removal of occult breast lesions using radiopharmaceuticals injected directly into the lesions and correlate radiological and histopathological findings. Methods One hundred and twenty patients were randomized into two groups (59 WL and 61 ROLL. The patients were requested to score the cosmetic appearance of their breast after surgery, and a numerical rating scale was used to measure pain on the first postoperative day. Clearance margins were considered at ≥ 10 mm for invasive cancer, ≥ 5 mm for ductal carcinoma in situ, and ≥ 1 mm for benign disease. Patients were subsequently treated according to the definitive histological result. When appropriate, different statistical tests were used in order to test the significance between the two groups, considering a P value Results WL and ROLL located all the occult breast lesions successfully. In the ROLL group, the specimen volume was smaller and there were more cases with clear margins (P Conclusion ROLL is an effective method for the excision of non-palpable breast lesions. It enables more careful planning of the cutaneous incision, leading to better aesthetic results, less postoperative symptoms, and smaller volumes of excised tissue.

  18. Bypassing the Limits of Ll Regularization: Convex Sparse Signal Processing Using Non-Convex Regularization

    Science.gov (United States)

    Parekh, Ankit

    Sparsity has become the basis of some important signal processing methods over the last ten years. Many signal processing problems (e.g., denoising, deconvolution, non-linear component analysis) can be expressed as inverse problems. Sparsity is invoked through the formulation of an inverse problem with suitably designed regularization terms. The regularization terms alone encode sparsity into the problem formulation. Often, the ℓ1 norm is used to induce sparsity, so much so that ℓ1 regularization is considered to be `modern least-squares'. The use of ℓ1 norm, as a sparsity-inducing regularizer, leads to a convex optimization problem, which has several benefits: the absence of extraneous local minima, well developed theory of globally convergent algorithms, even for large-scale problems. Convex regularization via the ℓ1 norm, however, tends to under-estimate the non-zero values of sparse signals. In order to estimate the non-zero values more accurately, non-convex regularization is often favored over convex regularization. However, non-convex regularization generally leads to non-convex optimization, which suffers from numerous issues: convergence may be guaranteed to only a stationary point, problem specific parameters may be difficult to set, and the solution is sensitive to the initialization of the algorithm. The first part of this thesis is aimed toward combining the benefits of non-convex regularization and convex optimization to estimate sparse signals more effectively. To this end, we propose to use parameterized non-convex regularizers with designated non-convexity and provide a range for the non-convex parameter so as to ensure that the objective function is strictly convex. By ensuring convexity of the objective function (sum of data-fidelity and non-convex regularizer), we can make use of a wide variety of convex optimization algorithms to obtain the unique global minimum reliably. The second part of this thesis proposes a non-linear signal

  19. Solar thermal

    International Nuclear Information System (INIS)

    Jones, J.

    2006-01-01

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m 3 - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become increasingly important as

  20. Solar thermal

    Energy Technology Data Exchange (ETDEWEB)

    Jones, J.

    2006-07-15

    While wind power is widely acknowledged as the most developed of the 'new' renewables, the number two technology, in terms of installed capacity functioning worldwide, is solar heating, or solar thermal. The author has investigated recent industry reports on how these markets are developing. The authors of an International Energy Agency (IEA) survey studied 41 countries in depth at the end of 2004, revealing that 141 million m{sup 3} - corresponding to an installed capacity of 98.4 GWth - were installed in the sample countries (these nations represent 3.74 billion people, about 57% of the world's population). The installed capacity within the areas studied represents approximately 85%-90% of the solar thermal market worldwide. The use of solar heating varies greatly between countries - even close neighbours - and between economic regions. Its uptake often has more to do with policy than solar resource. There is also different uptake of technology. In China, Europe and Japan, plants with flat-plate and evacuated tube collectors are used, mainly to heat water and for space heating. Unglazed plastic collectors, used mainly for swimming pool heating, meanwhile, dominate the North American markets. Though the majority of solar heating installations today are installed on domestic rooftops, the larger-scale installations should not be overlooked. One important part of the market is the hotel sector - in particular hotels in locations that serve the seasonal summer holiday market, where solar is extremely effective. Likewise hospitals and residential homes, multi-family apartment blocks and sports centres are all good examples of places where solar thermal can deliver results. There are also a growing number of industrial applications, where solar thermal can meet the hot water needs (and possibly more) of a range of industries, such as food processing and agriculture. The ability of solar to provide a heat source for cooling is expected to become