WorldWideScience

Sample records for 4c obs survey

  1. Integrated geophysical interpretation of the Valhall 4C OBS survey

    Energy Technology Data Exchange (ETDEWEB)

    Thomsen, Leon A.; Barkved, Olav I; Mueller, Michael C.; Haggard, Bill W.; Kommedal, Jan H.; Rosland, Boerge O.

    1998-12-31

    This presentation gives a brief classic example of a North Sea reservoir which cannot be imaged by conventional P-wave techniques. In two-dimensional P-wave sections, extending across the crest of the structure, the top of the chalk reservoir is depressed in time, and has low amplitude and coherency so that even its identification is uncertain. The classical interpretation of these effects is that, over geologic time, gas has leaked from the reservoir into the overburden, in the zone above the reservoir. This gas, while present in uneconomic concentrations, has the effect of lowering seismic velocities and increasing seismic attenuation. Efficient methods of seismic surveying were used for oil prediction in the reservoir. 6 refs.

  2. The B Fields in OB Stars (BOB) Survey

    NARCIS (Netherlands)

    Kholtygin, A.F.; Castro, N.; Fossati, L.; Hubrig, S.; Langer, N.; Morel, T.; Przybilla, N.; Schöller, M.; Carroll, T.; Ilyin, I.; Irrgang, A.; Oskinova, L.; Schneider, F.R.N.; Simon Díaz, S.; Briquet, M.; González, J.F.; Kharchenko, N.; Nieva, M.-F.; Scholz, R.-D.; de Koter, A.; Hamann, W.-R.; Herrero, A.; Maíz Apellániz, J.; Sana, H.; Arlt, R.; Barbá, R.; Dufton, P.; Mathys, G.; Piskunov, A.; Reisenegger, A.; Spruit, H.; Yoon, S. -C

    2015-01-01

    The B fields in OB stars (BOB) survey is an ESO large program collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects we

  3. The B Fields in OB Stars (BOB) Survey

    NARCIS (Netherlands)

    Morel, T.; Castro, N.; Fossati, L.; Hubrig, S.; Langer, N.; Przybilla, N.; Schöller, M.; Carroll, T.; Ilyin, I.; Irrgang, A.; Oskinova, L.; Schneider, F.R.N.; Simon Díaz, S.; Briquet, M.; González, J.F.; Kharchenko, N.; Nieva, M.-F.; Scholz, R.-D.; de Koter, A.; Hamann, W.-R.; Herrero, A.; Maíz Apellániz, J.; Sana, H.; Arlt, R.; Barbá, R.; Dufton, P.; Kholtygin, A.; Mathys, G.; Piskunov, A.; Reisenegger, A.; Spruit, H.; Yoon, S. -C

    2015-01-01

    The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects

  4. The B Fields in OB Stars (BOB) Survey

    CERN Document Server

    Morel, T; Fossati, L; Hubrig, S; Langer, N; Przybilla, N; Scholler, M; Carroll, T; Ilyin, I; Irrgang, A; Oskinova, L; Schneider, F R N; Diaz, S Simon; Briquet, M; Gonzalez, J F; Kharchenko, N; Nieva, M -F; Scholz, R -D; de Koter, A; Hamann, W -R; Herrero, A; Apellaniz, J Maiz; Sana, H; Arlt, R; Barba, R; Dufton, P; Kholtygin, A; Mathys, G; Piskunov, A; Reisenegger, A; Spruit, H; Yoon, S -C

    2014-01-01

    The B fields in OB stars (BOB) survey is an ESO large programme collecting spectropolarimetric observations for a large number of early-type stars in order to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. As of July 2014, a total of 98 objects were observed over 20 nights with FORS2 and HARPSpol. Our preliminary results indicate that the fraction of magnetic OB stars with an organised, detectable field is low. This conclusion, now independently reached by two different surveys, has profound implications for any theoretical model attempting to explain the field formation in these objects. We discuss in this contribution some important issues addressed by our observations (e.g., the lower bound of the field strength) and the discovery of some remarkable objects.

  5. Variability survey of brightest stars in selected OB associations

    CERN Document Server

    Laur, Jaan; Eenmäe, Tõnis; Tuvikene, Taavi; Leedjärv, Laurits

    2016-01-01

    The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed numerous variable stars but most of the luminous stars are often overexposed. Targeted campaigns can improve the time base of photometric data for those objects. The aim of this investigation is to study the variability of luminous stars at different timescales in young open clusters and OB associations. We monitored 22 open clusters and associations from 2011 to 2013 using a 0.25-m telescope. Variable stars were detected by comparing the overall light-curve scatter with measurement uncertainties. Variability was analysed by the light curve feature extraction tool FATS. Periods of pulsating stars were determined using the discrete Fourier transform code SigSpec. We then classified the variable stars based on their pulsation periods and available spectral information. We obtaine...

  6. A Photometric Survey of Ori OB1b

    Science.gov (United States)

    Merritt, Allison T.; Sherry, W.

    2011-01-01

    Several mechanisms have been suggested to describe the formation of sub-stellar mass objects (SSMOs), specifically brown dwarfs. Each proposed mechanism predicts a unique spatial distribution of the brown dwarfs relative to the O and B stars of the association. We have 9 square degrees of optical (VRI) data and 7 square degrees of NIR (JHK) data of Orion OB1b. The purpose of the survey is to obtain the photometric data that will allow us to determine the spatial distribution of brown dwarfs in this region and constrain the various formation theories. We present an overview of the survey, with an emphasis on the NIR data, as well as color-magnitude diagrams. This research was supported by the NOAO/KPNO Research Experiences for Undergraduates (REU) Program which is funded by the National Science Foundation Research Experiences for Undergraduates Program and the Department of Defense ASSURE program through Scientific Program Order No. 13 (AST-0754223) of the Cooperative Agreement No. AST-0132798 between the Association of Universities for Research in Astronomy (AURA) and the NSF.

  7. Variability survey of brightest stars in selected OB associations

    Science.gov (United States)

    Laur, Jaan; Kolka, Indrek; Eenmäe, Tõnis; Tuvikene, Taavi; Leedjärv, Laurits

    2017-02-01

    Context. The stellar evolution theory of massive stars remains uncalibrated with high-precision photometric observational data mainly due to a small number of luminous stars that are monitored from space. Automated all-sky surveys have revealed numerous variable stars but most of the luminous stars are often overexposed. Targeted campaigns can improve the time base of photometric data for those objects. Aims: The aim of this investigation is to study the variability of luminous stars at different timescales in young open clusters and OB associations. Methods: We monitored 22 open clusters and associations from 2011 to 2013 using a 0.25-m telescope. Variable stars were detected by comparing the overall light-curve scatter with measurement uncertainties. Variability was analysed by the light curve feature extraction tool FATS. Periods of pulsating stars were determined using the discrete Fourier transform code SigSpec. We then classified the variable stars based on their pulsation periods and available spectral information. Results: We obtained light curves for more than 20 000 sources of which 354 were found to be variable. Amongst them we find 80 eclipsing binaries, 31 α Cyg, 13 β Cep, 62 Be, 16 slowly pulsating B, 7 Cepheid, 1 γ Doradus, 3 Wolf-Rayet and 63 late-type variable stars. Up to 55% of these stars are potential new discoveries as they are not present in the Variable Star Index (VSX) database. We find the cluster membership fraction for variable stars to be 13% with an upper limit of 35%. Variable star catalogue (Tables A.1-A.10) and light curves are only available at the CDS via anonymous ftp to http://cdsarc.u-strasbg.fr (http://130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/598/A108

  8. THE CIDA-VISTA SURVEY IN ORION OB1

    Directory of Open Access Journals (Sweden)

    C. Briceño

    2011-01-01

    Full Text Available Presentamos los resultados preliminares de un sondeo óptico-infrarrojo sobre un área de -30 grados2 en la asociación Orión OB1, en las regiones extra-nube, donde las poblaciones estelares jóvenes son más evolucionadas. La combinación de un sondeo óptico multi-época con un mapeo profundo en el cercano infrarrojo, abre una ventana a lo que podemos esperar de la nueva generación de sondeos a gran escala como VISTA y LSST.

  9. Photometric Survey of Intermediate Mass Members of the Orion OB1 Association

    Science.gov (United States)

    Sherry, William; Walter, Frederick; Brittain, Sean; Kim, Jinyoung Serena

    2009-08-01

    We propose to survey 15 deg^2 of the OB1a and OB1b groups of the Orion OB1 association to measure UBVRI photometry of high and intermediate mass members of the association. This survey will address two goals. First, it will extend the photometric coverage of association members to cover the full spectrum of masses between 0.01 M_⊙ and 40 M_⊙ - extant photometry misses most stars in the range 1 M_⊙ to 3 M_⊙ (10B stars of the association (7B-V color-magnitude diagram made from published UBV photometry has association members distributed over a 2 magnitude wide swath. This surprisingly wide distribution suggests that there may be some problems with the published photometry. Few of these stars have measured Cousins R and I photometry, and the photoelectric UBV photometry comes from a variety of sources incorporating work spanning 2 or more decades.

  10. The Chandra Cygnus OB2 Legacy Survey: Design and X-ray Point Source Catalog

    CERN Document Server

    Wright, Nicholas J; Guarcello, Mario G; Aldcroft, Tom L; Kashyap, Vinay L; Damiani, Francesco; DePasquale, Joe; Fruscione, Antonella

    2014-01-01

    The Cygnus OB2 association is the largest concentration of young and massive stars within 2 kpc of the Sun, including an estimated 65 O-type stars and hundreds of OB stars. The Chandra Cygnus OB2 Legacy Survey is a large imaging program undertaken with the Advanced CCD Imaging Spectrometer onboard the Chandra X-ray Observatory. The survey has imaged the central 0.5 deg^2 of the Cyg OB2 association with an effective exposure of 120ks and an outer 0.35 deg^2 area with an exposure of 60ks. Here we describe the survey design and observations, the data reduction and source detection, and present a catalog of 8,000 X-ray point sources. The survey design employs a grid of 36 heavily (~50%) overlapping pointings, a method that overcomes Chandra's low off-axis sensitivity and produces a highly uniform exposure over the inner 0.5 deg^2. The full X-ray catalog is described here and is made available online.

  11. Large Scale Variability Surveys from Venezuela: Orion OB1 and beyond

    Science.gov (United States)

    Briceño, C.; Calvet, N.; Vivas, A. K.; Hartmann, L.

    We present our scheme and initial results for variability surveys spanning hundreds of square degrees near the celestial equator, carried out with an 8k x 8k CCD Mosaic Camera optimized for drift-scanning, installed on the 1m Schmidt telescope at the Venezuela National Astronomical Observatory. In the Orion OB1 association, one of the nearest and most active regions of star formation, we are conducting a 120 sqr.deg. VRIHalpha survey to map the low mass young stellar population in this region. The absence of dust and gas around the young stars in the ˜ 10 Myr Ori OB 1a sub-association suggests that star formation is a rapid process, and that molecular clouds do not last more than a few million years after the first stars are born. The lack of accretion indicators or near IR emission from inner dusty disks among stars in Ori OB 1a suggests that significant disk dissipation has occurred in a few Myr, possibly due to the coagulation/agglomeration of dust particles into larger bodies like planetesimals or planets. The results of our variability surveys will be made available through a massive database equipped with web-based data mining tools, as part of the effort leading to the International Virtual Observatory.

  12. The deep OB star population in Carina from the VST Photometric Hα Survey (VPHAS+)

    Science.gov (United States)

    Mohr-Smith, M.; Drew, J. E.; Napiwotzki, R.; Simón-Díaz, S.; Wright, N. J.; Barentsen, G.; Eislöffel, J.; Farnhill, H. J.; Greimel, R.; Monguió, M.; Kalari, V.; Parker, Q. A.; Vink, J. S.

    2017-02-01

    Massive OB stars are critical to the ecology of galaxies and yet our knowledge of OB stars in the Milky Way, fainter than V ˜ 12, remains patchy. Data from the VST Photometric Hα Survey (VPHAS+) permit the construction of the first deep catalogues of blue excess-selected OB stars, without neglecting the stellar field. A total of 14 900 candidates with 2MASS cross-matches are blue-selected from a 42 deg2 region in the Galactic plane, capturing the Carina Arm over the Galactic longitude range 282° ≲ ℓ ≲ 293°. Spectral energy distribution fitting is performed on these candidates' combined VPHAS+ u, g, r, i and 2MASS J, H, K magnitudes. This delivers effective temperature constraints, statistically separating O from early-B stars and high-quality extinction parameters, A0 and RV (random errors typically ˜0.1). The high-confidence O-B2 candidates number 5915 and a further 5170 fit to later B spectral type. Spectroscopy of 276 of the former confirms 97 per cent of them. The fraction of emission-line stars among all candidate B stars is 7-8 per cent. Greyer (RV > 3.5) extinction laws are ubiquitous in the region, over the distance range 2.5-3 to ˜10 kpc. Near prominent massive clusters, RV tends to rise, with particularly large and chaotic excursions to RV ˜ 5 seen in the Carina Nebula. The data reveal a hitherto unnoticed association of 108 O-B2 stars around the O5If+ star LSS 2063 (ℓ = 289.77°, b = -1.22°). Treating the OB star scaleheight as a constant within the thin disc, we find an orderly mean relation between extinction (A0) and distance in the Galactic longitude range, 287.6° < ℓ < 293.5°, and infer the subtle onset of thin-disc warping. A halo around NGC 3603, roughly a degree in diameter, of ˜500 O-B2 stars with 4 < A0(mag) < 7 is noted.

  13. The deep OB star population in Carina from the VST Photometric H$\\alpha$ Survey (VPHAS+)

    CERN Document Server

    Mohr-Smith, M; Napiwotzki, R; Simón-Díaz, S; Wright, N J; Barentsen, G; Eislöffel, J; Farnhill, H J; Greimel, R; Monguió, M; Kalari, V; Parker, Q A; Vink, J S

    2016-01-01

    Massive OB stars are critical to the ecology of galaxies, and yet our knowledge of OB stars in the Milky Way, fainter than $V \\sim 12$, remains patchy. Data from the VST Photometric H$\\alpha$ Survey (VPHAS+) permit the construction of the first deep catalogues of blue excess-selected OB stars, without neglecting the stellar field. A total of 14900 candidates with 2MASS cross-matches are blue-selected from a 42 square-degree region in the Galactic Plane, capturing the Carina Arm over the Galactic longitude range $282^{\\circ} \\lesssim \\ell \\lesssim 293^{\\circ}$. Spectral energy distribution fitting is performed on these candidates' combined VPHAS+ $u,g,r,i$ and 2MASS $J,H,K$ magnitudes. This delivers: effective temperature constraints, statistically separating O from early-B stars; high-quality extinction parameters, $A_0$ and $R_V$ (random errors typically $ 3.5$) extinction laws are ubiquitous in the region, over the distance range 2.5--3 kpc to $\\sim$10~kpc. Near prominent massive clusters, $R_V$ tends to ri...

  14. Optical and infrared counterparts of the X-ray sources detected in the Chandra Cygnus OB2 Legacy Survey

    CERN Document Server

    Guarcello, M G; Wright, N J; Naylor, T; Flaccomio, E; Kashyap, V L; Garcia-Alvarez, D

    2015-01-01

    The young massive OB association Cygnus OB2, in the Cygnus X complex, is the closest (1400 pc) star forming region to the Sun hosting thousands of young low mass stars and up to 1000 OB stars, among which are some of the most massive stars known in our Galaxy. This region holds great importance for several fields of modern astrophysics, such as the study of the physical properties of massive and young low-mass stars and the feedback provided by massive stars on star and planet formation process. Cygnus OB2 has been recently observed with Chandra/ACIS-I as part of the 1.08Msec Chandra Cygnus OB2 Legacy Project. This survey detected 7924 X-ray sources in a square degree area centered on Cyg OB2. Since a proper classification and study of the observed X-ray sources also requires the analysis of their optical and infrared counterparts, we combined a large and deep set of optical and infrared catalogs available for this region with our new X-ray catalog. In this paper we describe the matching procedure and present...

  15. Massive open star clusters using the VVV survey V. Young clusters with an OB stellar population

    CERN Document Server

    Alegría, S Ramírez; Chené, A -N; Bonatto, C; Kurtev, R; Amigo, P; Kuhn, M; Gromadzki, M; Carballo-Bello, J A

    2016-01-01

    The ESO public survey VISTA Variables in the V\\'ia L\\'actea (VVV) has contributed with deep multi-epoch photometry of the Galactic bulge and the adjacent part of the disk over 526 square degrees. More than a hundred cluster candidates have been reported thanks to this survey. We present the fifth article in a series of papers focused on young and massive clusters discovered in the VVV survey. In this paper, we present the physical characterization of five clusters with a spectroscopically confirmed OB-type stellar population. To characterize the clusters, we used near-infrared photometry ($J$, $H,$ and $K_S$) from the VVV survey and near-infrared $K$-band spectroscopy from ISAAC at VLT, following the methodology presented in the previous articles of the series. All clusters in our sample are very young (ages between 1-20 Myr), and their total mass are between $(1.07^{+0.40}_{-0.30})\\cdot10^2$ $M_{\\odot}$ and $(4.17^{+4.15}_{-2.08})\\cdot10^3$ $M_{\\odot}$. We observed a relation between the clusters total mass ...

  16. A Deuteration Survey of the Clump Population in the Gemini OB1 Molecular Cloud

    Science.gov (United States)

    Henrici, Andrew Scott; Shirley, Yancy L.; Svoboda, Brian E.

    2017-01-01

    Recent maps of dust continuum emission from entire molecular clouds at submillimeter wavelengths have made it possible to survey and study the chemistry of entire core and clump populations within a single cloud. One very strong chemical process in star-forming regions is the fractionation of deuterium in molecules, which results in an increase in the deuterium ratio many orders of magnitude over the ISM [D]/[H] ratio and provides a chemical probe of cold, dense regions. We present a survey of DCO+ 3-2 and N2D+ 3-2 toward the clump population in the high-mass, star-forming Gemini OB1 Molecular Cloud identified from 1.1 mm continuum imaging by the Bolocam Galactic Plane Survey. The peak 1.1 mm continuum positions of 52 clumps in the range 188°≤ l ≤194° were observed with the 10m Heinrich Hertz Submillimeter Telescope. We find that DCO+ emission is detected toward 90% of the clumps with a median deuterium ratio of 0.01 while N2D+ emission is detected toward only 25% of the clumps. The DCO+ fractionation anti-correlates with gas kinetic temperature and linewidth, a measure of the amount of turbulence within the clumps. We compare the deuteration ratios of with physical properties of the clumps and their evolutionary stage.

  17. The CIDA-QUEST Large Scale Variability Survey in the Orion OB Association initial results

    CERN Document Server

    Briceño, C; Calvet, N; Hartmann, L; Briceno, Cesar; Calvet, Nuria; Hartmann, Lee

    1999-01-01

    Using the 8k x 8k CCD Mosaic Camera on the 1m Schmidt telescope in Venezuela, we are conducting a large-scale, deep optical, multiepoch, photometric (BVRIHa) survey over 120 sq.deg. in the Orion OB association, aimed at identifying the low mass stellar populations with ages less than about 10 Myr. We present initial results for a 34 sq.deg. area spanning Orion 1b, 1a and the B Cloud. Using variability as our main selection criterion we derive much cleaner samples than with the usual single-epoch photometric selection, allowing us to attain a much higher efficiency in follow up spectroscopy and resulting in an preliminary list of 74 new low-mass (~ 0.4 Msun) pre-main sequence stars. Though preliminary, this list of new T Tauri stars already suggests that the fraction of accreting young stars in 1a is much lower than in 1b, which would be expected if 1a is indeed older than 1b. We are analyzing in detail the light curves of these new stars, and spectroscopy of further candidates is under way.

  18. A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors

    Science.gov (United States)

    2014-02-01

    Printed in the U.S.A. A HIGH ANGULAR RESOLUTION SURVEY OF MASSIVE STARS IN CYGNUS OB2: RESULTS FROM THE HUBBLE SPACE TELESCOPE FINE GUIDANCE SENSORS...angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the fine guidance sensor 1R (FGS1r) on the Hubble Space...al. 2009) and imaging observations (Maı́z Apellániz 2010). The fine guidance sensors (FGSs) aboard the Hubble Space Telescope (HST) provide us with

  19. A High Angular Resolution Survey of Massive Stars in Cygnus OB2: Results from the Hubble Space Telescope Fine Guidance Sensors

    CERN Document Server

    Caballero-Nieves, Saida M; Gies, Douglas R; Wallace, Debra J; DeGioia-Eastwood, Katherine; Herrero, Artemio; Jao, Wei-Chun; Mason, Brian D; Massey, Philip; Moffat, Anthony F J; Walborn, Nolan R

    2013-01-01

    We present results of a high angular resolution survey of massive OB stars in the Cygnus OB2 association that we conducted with the Fine Guidance Sensor 1R (FGS1r) on the Hubble Space Telescope. FGS1r is able to resolve binary systems with a magnitude difference delta-V 60%. One of the new discoveries is a companion to the hypergiant star MT 304 = Cyg OB2-12, and future measurements of orbital motion should provide mass estimates for this very luminous star.

  20. Toward Complete Statistics of Massive Binary Stars: Penultimate Results from the Cygnus OB2 Radial Velocity Survey

    Science.gov (United States)

    Kobulnicky, Henry A.; Kiminki, Daniel C.; Lundquist, Michael J.; Burke, Jamison; Chapman, James; Keller, Erica; Lester, Kathryn; Rolen, Emily K.; Topel, Eric; Bhattacharjee, Anirban; Smullen, Rachel A.; Vargas Álvarez, Carlos A.; Runnoe, Jessie C.; Dale, Daniel A.; Brotherton, Michael M.

    2014-08-01

    We analyze orbital solutions for 48 massive multiple-star systems in the Cygnus OB2 association, 23 of which are newly presented here, to find that the observed distribution of orbital periods is approximately uniform in log P for P power law provides a statistically compelling prescription, but if features are ignored, a power law with exponent β ~= -0.22 provides a crude approximation over P = 1.4-2000 days, as does a piece-wise linear function with a break near 45 days. The cumulative period distribution flattens at P > 45 days, even after correction for completeness, indicating either a lower binary fraction or a shift toward low-mass companions. A high degree of similarity (91% likelihood) between the Cyg OB2 period distribution and that of other surveys suggests that the binary properties at P period P < 45 days. Completeness corrections imply a binary fraction near 55% for P < 5000 days. The observed distribution of mass ratios 0.2 < q < 1 is consistent with uniform, while the observed distribution of eccentricities 0.1 < e < 0.6 is consistent with uniform plus an excess of e ~= 0 systems. We identify six stars, all supergiants, that exhibit aperiodic velocity variations of ~30 km s-1 attributed to atmospheric fluctuations.

  1. Toward Complete Statistics of Massive Binary Stars: Penultimate Results from the Cygnus OB2 Radial Velocity Survey

    CERN Document Server

    Kobulnicky, Henry A; Lundquist, Michael J; Burke, Jamison; Chapman, James; Keller, Erica; Lester, Kathryn; Rolen, Emily K; Topel, Eric; Bhattacharjee, Anirban; Smullen, Rachel A; Alvarez, Carlos A Vargas; Runnoe, Jessie C; Dale, Daniel A; Brotherton, Michael M

    2014-01-01

    We analyze orbital solutions for 48 massive multiple-star systems in the Cygnus OB2 Association, 23 of which are newly presented here, to find that the observed distribution of orbital periods is approximately uniform in log P for P 45 d, even after correction for completeness, indicating either a lower binary fraction or a shift toward low-mass companions. A high degree of similarity (91% likelihood) between the Cyg OB2 period distribution and that of other surveys suggests that the binary properties at P<25 d are determined by local physics of disk/clump fragmentation and are relatively insensitive to environmental and evolutionary factors. Fully 30% of the unbiased parent sample is a binary with period P < 45 d. Completeness corrections imply a binary fraction near 55% for P < 5000 d. The observed distribution of mass ratios 0.2

  2. An ALMA Continuum Survey of Circumstellar Disks in the Upper Scorpius OB Association

    CERN Document Server

    Carpenter, John M; Isella, Andrea

    2014-01-01

    We present ALMA 880 micron continuum observations of 20 K and M-type stars in the Upper Scorpius OB association that are surrounded by protoplanetary disks. These data are used to measure the dust content in disks around low mass stars (0.1-1.6 Msun) at a stellar age of 5-11 Myr. Thirteen sources were detected in the 880 micron dust continuum at >3 sigma with inferred dust masses between 0.3 and 52 Mearth. The dust masses tend to be higher around the more massive stars, but the significance is marginal in that the probability of no correlation is p ~ 0.03. The evolution in the dust content in disks was assessed by comparing the Upper Sco observations with published continuum measurements of disks around ~ 1-2 Myr stars in the Class II stage in the Taurus molecular cloud. While the dust masses in the Upper Sco disks are on average lower than in Taurus, any difference in the dust mass distributions is significant at less than 3sigma. For stellar masses between 0.49 Msun and 1.6 Msun, the mean dust mass in disks...

  3. The CIDA-QUEST large-scale survey of Orion OB1: evidence for rapid disk dissipation in a dispersed stellar population.

    Science.gov (United States)

    Briceño, C; Vivas, A K; Calvet, N; Hartmann, L; Pacheco, R; Herrera, D; Romero, L; Berlind, P; Sánchez, G; Snyder, J A; Andrews, P

    2001-01-05

    We are conducting a large-scale, multiepoch, optical photometric survey [Centro de Investigaciones de Astronomia-Quasar Equatorial Survey Team (CIDA-QUEST)] covering about 120 square degrees to identify the young low-mass stars in the Orion OB1 association. We present results for an area of 34 square degrees. Using photometric variability as our main selection criterion, as well as follow-up spectroscopy, we confirmed 168 previously unidentified pre-main sequence stars that are about 0.6 to 0.9 times the mass of the sun (Mo), with ages of about 1 million to 3 million years (Ori OB1b) and about 3 million to 10 million years (Ori OB1a). The low-mass stars are spatially coincident with the high-mass (at least 3 Mo) members of the associations. Indicators of disk accretion such as Halpha emission and near-infrared emission from dusty disks fall sharply from Ori OB1b to Ori OB1a, indicating that the time scale for disk dissipation and possibly the onset of planet formation is a few million years.

  4. The Gaia-ESO Survey: Discovery of a spatially extended low-mass population in the Vela OB2 association

    CERN Document Server

    Sacco, G G; Randich, S; Franciosini, E; Jackson, R J; Cottaar, M; Spina, L; Palla, F; Mapelli, M; Alfaro, E J; Bonito, R; Damiani, F; Frasca, A; Klutsch, A; Lanzafame, A; Bayo, A; Barrado, D; Jimenez-Esteban, F; Gilmore, G; Micela, G; Vallenari, A; Prieto, C Allende; Flaccomio, E; Carraro, G; Costado, M T; Jofre, P; Lardo, C; Magrini, L; Morbidelli, L; Prisinzano, L; Sbordone, L

    2015-01-01

    The nearby (distance~350-400 pc), rich Vela OB2 association, includes $\\gamma^2$ Velorum, one of the most massive binaries in the solar neighbourhood and an excellent laboratory for investigating the formation and early evolution of young clusters. Recent Gaia-ESO survey observations have led to the discovery of two kinematically distinct populations in the young (10-15 Myr) cluster immediately surrounding $\\gamma^2$ Velorum. Here we analyse the results of Gaia-ESO survey observations of NGC 2547, a 35 Myr cluster located two degrees south of $\\gamma^2$ Velorum. The radial velocity distribution of lithium-rich pre-main sequence stars shows a secondary population that is kinematically distinct from and younger than NGC 2547. The radial velocities, lithium absorption lines, and the positions in a colour-magnitude diagram of this secondary population are consistent with those of one of the components discovered around $\\gamma^2$ Velorum. This result shows that there is a young, low-mass stellar population spread...

  5. VizieR Online Data Catalog: RIOTS4: spectroscopic survey of SMC field OB stars (Lamb+, 2016)

    Science.gov (United States)

    Lamb, J. B.; Oey, M. S.; Segura-Cox, D. M.; Graus, A. S.; Kiminki, D. C.; Golden-Marx, J. B.; Parker, J. W.

    2016-04-01

    Runaways and Isolated O-Type Star Spectroscopic Survey of the SMC (RIOTS4) targets a spatially complete sample of 374 uniformly selected candidate field OB stars in the SMC. Our targets are identified by Oey et al. (2004, J/AJ/127/1632). We observed the RIOTS4 survey targets over a five-year period from 2006 September to 2011 October using spectrographs on the Magellan telescopes at Las Campanas Observatory. The majority of our observations were obtained with the Inamori-Magellan Areal Camera and Spectrograph (IMACS) in the f/4 multi-slit mode on the Magellan Baade telescope (slit widths of either 0.7" or 1.0", yielding spectral resolutions of R~3700 and R~2600, respectively). With IMACS f/4 out of commission during our 2011 observations, we also operated IMACS in f/2 mode (we used either a 0.5" or 0.7" slit width, which yield spectral resolutions of R~1000 and R~1300, respectively). The remaining targets were observed using the Magellan Inamori Kyocera Echelle (MIKE) Spectrograph on the Magellan Clay telescope (R~28000). All MIKE observations occurred in 2010 November. (2 data files).

  6. Long-Baseline Interferometric Multiplicity Survey of the Sco-Cen OB Association

    CERN Document Server

    Rizzuto, A C; Robertson, J G; Kok, Y; Tuthill, P G; Warrington, B A; Haubois, X; Tango, W J; Norris, B; Brummelaar, T ten; Kraus, A L; Jacob, A; Laliberte-Houdeville, C

    2013-01-01

    We present the first multiplicity-dedicated long baseline optical interferometric survey of the Scorpius-Centaurus-Lupus-Crux association. We used the Sydney University Stellar Interferometer to undertake a survey for new companions to 58 Sco-Cen B- type stars and have detected 24 companions at separations ranging from 7-130mas, 14 of which are new detections. Furthermore, we use a Bayesian analysis and all available information in the literature to determine the multiplicity distribution of the 58 stars in our sample, showing that the companion frequency is F = 1.35 and the mass ratio distribution is best described as a power law with exponent equal to -0.46, agreeing with previous Sco-Cen high mass work and differing significantly from lower-mass stars in Tau-Aur. Based on our analysis, we estimate that among young B-type stars in moving groups, up to 23% are apparently single stars. This has strong implications for the understanding of high-mass star formation, which requires angular momentum dispersal thr...

  7. The VLT-FLAMES Tarantula Survey XVI. The optical+NIR extinction laws in 30 Doradus and the photometric determination of the effective temperatures of OB stars

    CERN Document Server

    Apellániz, J Maíz; Barbá, R H; Gräfener, G; Bestenlehner, J M; Crowther, P A; García, M; Herrero, A; Sana, H; Simón-Díaz, S; Taylor, W D; van Loon, J Th; Vink, J S; Walborn, N R

    2014-01-01

    Context: The commonly used extinction laws of Cardelli et al. (1989) have limitations that, among other issues, hamper the determination of the effective temperatures of O and early B stars from optical+NIR photometry. Aims: We aim to develop a new family of extinction laws for 30 Doradus, check their general applicability within that region and elsewhere, and apply them to test the feasibility of using optical+NIR photometry to determine the effective temperature of OB stars. Methods: We use spectroscopy and NIR photometry from the VLT-FLAMES Tarantula Survey and optical photometry from HST/WFC3 of 30 Doradus and we analyze them with the software code CHORIZOS using different assumptions such as the family of extinction laws. Results: We derive a new family of optical+NIR extinction laws for 30 Doradus and confirm its applicability to extinguished Galactic O-type systems. We conclude that by using the new extinction laws it is possible to measure the effective temperatures of OB stars with moderate uncertain...

  8. The Primordial Binary Population in OB Associations

    NARCIS (Netherlands)

    Kouwenhoven, M.B.N.; Brown, A.G.A.; Gualandris, A.; Kaper, L.; Portegies Zwart, S.F.; Zinnecker, H.; Allen, C.; Scarfe, C.

    2004-01-01

    We present the first results of our adaptive optics survey of 200 (mainly) A-type stars in the nearby OB association Sco OB2, which we will use, together with literature data and detailed simulations of young star clusters, to determine the primordial binary population.

  9. A Hectochelle Radial Velocity Survey of Cep OB3b: An ONC like cluster at late gas dispersal phase

    Science.gov (United States)

    Karnath, Nicole; Allen, Thomas; Prchlik, Jakub; Gutermuth, Robert A.; Megeath, Samuel Thomas; Pipher, Judith; Wolk, Scott J.

    2016-01-01

    Cep OB3b is a young (~3-5 Myr), late gas dispersal cluster of roughly 3000 members broken into two sub-clusters (Eastern and Western) at a distance of 700pc; it is a rare example of nearby cluster in the late stages of gas dispersal and appears to be a more evolved analog to the Orion Nebular Cluster. As part of an ongoing multi wavelength study, we focus on Hectochelle data from the MMT to measure the radial velocities of 499 stars. After removing binaries, outliers, and imposing a minimum R value to the cross correlation, we obtain radial velocities of 57 previously identified members, with an average error of 1.7 km/s. There is no observed variation in radial velocity across the cluster in right ascension or declination. The preferred mechanism for this type of kinematic evolution is that any initial kinematic structure from formation may have been erased and that minimal or no rotation is present in the cluster. However, the Eastern sub-cluster, containing the most massive star in the field, an O7 star, has a higher velocity dispersion than the Western sub-cluster, which contains several B stars. We will compare these results to CO maps of the residual gas in the cluster and discuss possible reasons for this difference. Finally, we will assess whether the cluster is bound or in a state of expansion.

  10. The Bolocam Galactic Plane Survey -- III. Characterizing Physical Properties of Massive Star-Forming Regions in the Gemini OB1 Molecular Cloud

    CERN Document Server

    Dunham, Miranda K; Evans, Neal J; Cyganowski, Claudia J; Aguirre, James; Bally, John; Battersby, Cara; Bradley, Eric Todd; Dowell, Darren; Drosback, Meredith; Ginsburg, Adam; Glenn, Jason; Harvey, Paul; Merello, Manuel; Schlingman, Wayne; Shirley, Yancy L; Stringfellow, Guy S; Walawender, Josh; Williams, Jonathan P

    2010-01-01

    We present the 1.1 millimeter Bolocam Galactic Plane Survey (BGPS) observations of the Gemini OB1 molecular cloud complex, and targeted ammonia observations of the BGPS sources. When paired with molecular spectroscopy of a dense gas tracer, millimeter observations yield physical properties such as masses, radii, mean densities, kinetic temperatures and line widths. We detect 34 distinct BGPS sources above 5-sigma=0.37 Jy/beam with corresponding 5-sigma detections in the ammonia (1,1) transition. Eight of the objects show water maser emission (20%). We find a mean millimeter source FWHM of 1.12 pc, and a mean kinetic temperature of 20 K for the sample of 34 BGPS sources. The observed ammonia line widths are dominated by non-thermal motions, typically found to be a few times the thermal sound speed expected for the derived kinetic temperature. We calculate the mass for each source from the millimeter flux assuming the sources are isothermal and find a mean isothermal mass within a 120" aperture of 230 +/- 180 s...

  11. Balanced {C_4, C_5}-Quatrefoil Systems

    OpenAIRE

    USHIO, Kazuhiko

    2004-01-01

    In graph theory, the decomposition problems of graphs are very important topics. Various types of decompositions of many graphs can be seen in the literature of gaph theory. We give the necessary and sufficient condition for the existence of a balanced {C_4, C_5}-quatrefoil decomposition of K_n for each of (C_4, C_4, C_4, C_4)-quatrefoil, (C_4, C_4, C_4, C_5)-quatrefoil, (C_4, C_4, C_5, C_5)-quatrefoil, (C_4, C_5, C_5, C_5)-quatrefoil, and (C_5, C_5, C_5, C_5)-quatrefoil. These decompositions...

  12. e-MERLIN 21 cm constraints on the mass-loss rates of OB stars in Cyg OB2

    Science.gov (United States)

    Morford, J. C.; Fenech, D. M.; Prinja, R. K.; Blomme, R.; Yates, J. A.

    2016-11-01

    We present e-MERLIN 21 cm (L-band) observations of single luminous OB stars in the Cygnus OB2 association, from the Cyg OB2 Radio Survey Legacy programme. The radio observations potentially offer the most straightforward, least model-dependent, determinations of mass-loss rates, and can be used to help resolve current discrepancies in mass-loss rates via clumped and structured hot star winds. We report here that the 21 cm flux densities of O3 to O6 supergiant and giant stars are less than ˜70 μJy. These fluxes may be translated to `smooth' wind mass-loss upper limits of ˜4.4-4.8 × 10-6 M⊙ yr -1 for O3 supergiants and ≲2.9 × 10-6 M⊙ yr -1 for B0 to B1 supergiants. The first ever resolved 21 cm detections of the hypergiant (and luminous blue variable candidate) Cyg OB2 #12 are discussed; for multiple observations separated by 14 d, we detect an ˜69 per cent increase in its flux density. Our constraints on the upper limits for the mass-loss rates of evolved OB stars in Cyg OB2 support the model that the inner wind region close to the stellar surface (where Hα forms) is more clumped than the very extended geometric region sampled by our radio observations.

  13. Ice Jams the Ob River

    Science.gov (United States)

    2007-01-01

    Russia's Ob River flows from south to north, and each summer, it thaws in the same direction. The result is that an ice jam sits downstream from thawed portions of the river, which is laden with heavy runoff from melted snow. On June 29, 2007, the Moderate Resolution Imaging Spectroradiometer (MODIS) flying on NASA's Terra satellite captured this image of the almost completely thawed Ob River. The scene is typical for early summer. South of the ice jam, the Gulf of Ob is swollen with pent-up run-off, and upstream from that, the river is widened as well. Unable to carve through frozen land, the river has little choice but to overflow its banks. For a comparison of early summer and autumn conditions, see Flooding on the Ob River in the Earth Observatory's Natural Hazards section. Besides the annual overflow, this image captures other circumstances of early summer. Sea ice is retreating from the Kara Sea. A lingering line of snow cover snakes its way along the Ob River, to the west. And while the land is lush and green in the south, it appears barren and brown in the north. Near the mouth of the river and the Kara Sea, the land is cold-adapted tundra, with diminutive plants and a short growing season. Just as the ice plugging the river had yet to thaw in the Far North's short summer, the tundra had not yet to greened up either. In this image it still appears lifeless beige. NASA image courtesy Jeff Schmaltz, MODIS Rapid Response Team, Goddard Space Flight Center

  14. The Low-mass Populations in OB Associations

    CERN Document Server

    Briceño, C; Sherry, W; Mamajek, E; Mathieu, R; Walter, F; Zinnecker, H; Briceno, Cesar; Preibisch, Thomas; Sherry, William; Mamajek, Eric; Mathieu, Robert; Walter, Frederick; Zinnecker, Hans

    2006-01-01

    Low-mass stars 0.1 ~< M ~< 1 Msun) in OB associations are key to addressing some of the most fundamental problems in star formation. The low-mass stellar populations of OB associations provide a snapshot of the fossil star-formation record of giant molecular cloud complexes. Large scale surveys have identified hundreds of members of nearby OB associations, and revealed that low-mass stars exist wherever high-mass stars have recently formed. The spatial distribution of low-mass members of OB associations demonstrate the existence of significant substructure ("subgroups"). This "discretized" sequence of stellar groups is consistent with an origin in short-lived parent molecular clouds within a Giant Molecular Cloud Complex. The low-mass population in each subgroup within an OB association exhibits little evidence for significant age spreads on time scales of ~10 Myr or greater, in agreement with a scenario of rapid star formation and cloud dissipation. The Initial Mass Function (IMF) of the stellar popula...

  15. No evidence of disk destruction by OB stars

    Science.gov (United States)

    Richert, Alexander J. W.; Feigelson, Eric

    2015-01-01

    It has been suggested that the hostile environments observed in massive star forming regions are inhospitable to protoplanetary disks and therefore to the formation of planets. The Orion Proplyds show disk evaporation by extreme ultraviolet (EUV) photons from Theta1 Orionis C (spectral type O6). In this work, we examine the spatial distributions of disk-bearing and non-disk bearing young stellar objects (YSOs) relative to OB stars in 17 massive star forming regions in the MYStIX (Massive Young Star-Forming Complex Study in Infrared and X-ray) survey. Any tendency of disky YSOs, identified by their infrared excess, to avoid OB stars would reveal complete disk destruction.We consider a sample of MYStIX that includes 78 O3-O9 stars, 256 B stars, 5,606 disky YSOs, and 5,794 non-disky YSOs. For each OB star, we compare the cumulative distribution functions of distances to disky and non-disky YSOs. We find no significant avoidance of OB stars by disky YSOs. This result indicates that OB stars are not sufficiently EUV-luminous and long-lived to completely destroy a disk within its ordinary lifetime. We therefore conclude that massive star forming regions are not clearly hostile to the formation of planets.

  16. Chandra observations of Cygnus OB2

    CERN Document Server

    Wright, Nicholas J; Drew, Janet E; Vink, Jorick S

    2011-01-01

    Cygnus OB2 is the nearest example of a massive star forming region, containing over 50 O-type stars and hundreds of B-type stars. We have analyzed two Chandra pointings in Cyg OB2, detecting ~1700 X-ray sources, of which ~1450 are thought to be members of the association. Optical and near-IR photometry has been obtained for ~90% of these sources from recent deep Galactic plane surveys. We have performed isochrone fits to the near-IR color-magnitude diagram, deriving ages of 3.5(+0.75,-1.0) and 5.25(+1.5,-1.0) Myrs for sources in the two fields, both with considerable spreads around the pre-MS isochrones. The presence of a second population in the region, somewhat older than the present-day O-type stars, has been suggested by other authors and fits with the ages derived here. The fraction of sources with inner circumstellar disks (as traced by the K-band excess) is found to be very low, but appropriate for a population of age ~5 Myrs. We measure the stellar mass functions and find a power-law slope of Gamma = ...

  17. The Nearest OB Association: Scorpius-Centaurus (Sco OB2)

    CERN Document Server

    Preibisch, Thomas

    2008-01-01

    We summarize observational results on the stellar population and star formation history of the Scorpius-Centaurus OB Association (Sco OB2), the nearest region of recent massive star formation. It consists of three subgroups, Upper Scorpius (US), Upper Centaurus-Lupus (UCL), and Lower Centaurus-Crux (LCC) which have ages of about 5, 17, and 16 Myr. In Upper Scorpius, numerous studies have recently revealed hundreds of low-mass association members, including dozens of brown dwarfs. The empirical mass function could be established over the full stellar mass range from 0.1 M_sun up to 20 M_sun, and was found to be consistent with recent determinations of the field initial mass function. A narrow range of ages around 5 Myr was found for the low-mass stars, the same age as had previously (and independently) been derived for the high-mass members. This supports earlier indications that the star formation process in US was triggered, and agrees with previous conjectures that the triggering event was a supernova- and ...

  18. The Puppis region and the last crusade for faint OB stars

    Science.gov (United States)

    Orsatti, Ana M.

    1992-08-01

    UBV photoelectric and photographic measurements of OB stars from a list of 397 OB stars and 5 early-type supergiants and from the Luminous Stars Survey are presented. The galactic distribution of the OB stars in the region shows concentrations around the open clusters Ruprecht 44 and Ruprecht 55, and the presence of an important grouping of young stars located far below the plane. The distribution in latitude shows that young stars in the region are not restricted to a thin sheet around the plane but are spread over negative latitudes reaching at least b = -5 deg. In longitude, the OB distribution exhibits a concentration of Ob stars in the interval 244-251 deg; this is argued to be due to the presence of the local arm extension.

  19. The Dynamics of an Expanding OB Association

    CERN Document Server

    Wright, Nicholas J; Drake, Jeremy J; Drew, Janet E; Guarcello, Mario; Navacues, David Barrado y

    2012-01-01

    We present 3-dimensional kinematical observations of the massive OB association Cygnus OB2 to identify the mechanisms responsible for disrupting young star clusters. The picture revealed by these observations is of a highly-substructured, dynamically unmixed OB association that does not exhibit the position-velocity correlations predicted by the theories of infant mortality or tidal stripping. These observations would appear to support a picture of hierarchical star formation.

  20. Were All Massive Stars Born in OB Associations and Clusters?

    CERN Document Server

    Chu, You-Hua

    2007-01-01

    It has been commonly conjectured that all massive >10 Msun stars are born in OB associations or clusters. Many O and B stars in the Galaxy or the Magellanic Clouds appear to exist in isolation, however. While some of these field OB stars have been ejected from their birthplaces, some are too far away from massive star forming regions to be runaways. Can massive stars form in isolation? The Spitzer survey of the Large Magellanic Cloud (aka SAGE) provides a unique opportunity for us to investigate and characterize the formation sites of massive stars for an entire galaxy. We have identified all massive young stellar objects (YSOs) in the Large Magellanic Cloud. We find that ~85% of the massive YSOs are in giant molecular clouds and ~65% are in OB associations. Only ~7% of the massive YSOs are neither in OB associations nor in giant molecular clouds. This fraction of isolated massive stars in the Large Magellanic Cloud is comparable to the 5-10% found in the Galaxy.

  1. MULTIWAVELENGTH SYSTEMATICS OF OB SPECTRA

    Directory of Open Access Journals (Sweden)

    Nolan R. Walborn

    2008-01-01

    Full Text Available La sistematica de los espectros OB es resumida, en el rango optico dominado por líneas fotosféricas, y en el lejano ultravioleta (tanto de IUE como de FUSE donde dominan perfiles de los vientos estelares. Primero, las tendencias bidimensionales (temperatura, luminosidad en los espectros normales son examinadas. Luego, establecida la estructura de referencia normal, se pueden reconocer relativo a ésta varias categorías de objetos peculiares, las cuales revelan sendos fenómenos de importancia estructural y/o evolutiva. Se incluyen anomalías de CNO en tipos O tempranos y tardíos, tres variedades de rotadores rápidos, objetos de transición Of/WN de alta y baja temperatura, y la recientemente descubierta segunda estrella magnética de tipo O conocida. Aunque se han adelantado y se siguen adelantando las interpretaciones físicas de estas tendencias y anomalías, mayor atención al modelaje de la sistemática aceleraría el progreso a futuro en la opinión de este autor. Finalmente, se presentan resultados preliminares de un estudio con Chandra en alta resolución de los espectros OB en el rangode rayos X. Éstos proveen evidencias de que, tal como sucedió anteriormente en el UV, tendencias morfológicas sistemáticas existen en el dominio de rayos X, las cuales son correlacionadas con los tipos espectrales ´opticos, y de allá con los parámetros estelares fundamentales, al contrario de la opinión especialista prevaleciente.

  2. The primordial binary population in ob associations

    Directory of Open Access Journals (Sweden)

    M. B. N. Kouwenhoven

    2004-01-01

    Full Text Available Presentamos los primeros resultados de nuestro sondeo con optica adaptativa de 200 estrellas principalmente de tipo A en la asociaci on OB cercana Sco OB2. Estos resultados, junto con datos de la literatura y simulaciones detalladas de c umulos j ovenes, ser an utilizados para determinar la poblaci on primordial de binarias.

  3. Open Clusters and OB Associations: a Review

    Directory of Open Access Journals (Sweden)

    Anthony G. A. Brown

    2001-01-01

    Full Text Available In this review on open clusters and OB associations I discuss some recent developments to which Latin American astronomers have contributed. Subsequently, results from the Hipparcos mission concerning OB associations, the Hyades and other nearby open clusters will be discussed. I end with a brief discussion of current theories of star cluster formation and prospects for future research.

  4. Efforts to Improve Immunization Coverage during Pregnancy among Ob-Gyns

    Directory of Open Access Journals (Sweden)

    Katherine M. Jones

    2016-01-01

    Full Text Available Background. Influenza and Tdap vaccines are vital factors for improving maternal and neonatal health outcomes. Methods. A prospective, longitudinal study was conducted to determine whether the American College of Obstetricians and Gynecologists’ (ACOG’s efforts to increase ob-gyn use of their immunization toolkits and vaccination administration were successful. Pre- and postintervention questionnaires were mailed to a random sample of 1,500 ACOG members between August 2012 and July 2015. Results. Significantly more postintervention survey ob-gyns reported that they received the immunization toolkits than preintervention survey ob-gyns (84.5% versus 67.0%, p<.001. The large majority of ob-gyns from both surveys (76.9% versus 78.9% reported that they offered or planned to offer influenza vaccinations to their patients for the 2012-2013 and 2014-2015 flu seasons. Postintervention survey respondents were significantly more likely than preintervention survey participants to report that they routinely offer Tdap vaccinations to all patients during pregnancy (76.8% versus 59.3%, p<.001. Conclusion. ACOG’s efforts to improve ob-gyn use of immunization toolkits and vaccine administration appear to have been successful in several ways. ACOG’s toolkits are an example of an effective intervention to overcome barriers to offering vaccines and help improve influenza and Tdap immunization coverage for pregnant women.

  5. Impaired Muscle Regeneration in Ob/ob and Db/db Mice

    Directory of Open Access Journals (Sweden)

    Mai-Huong Nguyen

    2011-01-01

    Full Text Available In obesity and type 2 diabetes, efficient skeletal muscle repair following injury may be required, not only for restoring muscle structure and function, but also for maintaining exercise capacity and insulin sensitivity. The hypothesis of this study was that muscle regeneration would be impaired in ob/ob and db/db mice, which are common mouse models of obesity and type 2 diabetes. Muscle injury was produced by cardiotoxin injection, and regeneration was assessed by morphological and immunostaining techniques. Muscle regeneration was delayed in ob/ob and db/db mice, but not in a less severe model of insulin resistance – feeding a high-fat diet to wild-type mice. Angiogenesis, cell proliferation, and myoblast accumulation were also impaired in ob/ob and db/db mice, but not the high-fat diet mice. The impairments in muscle regeneration were associated with impaired macrophage accumulation; macrophages have been shown previously to be required for efficient muscle regeneration. Impaired regeneration in ob/ob and db/db mice could be due partly to the lack of leptin signaling, since leptin is expressed both in damaged muscle and in cultured muscle cells. In summary, impaired muscle regeneration in ob/ob and db/db mice was associated with reduced macrophage accumulation, angiogenesis, and myoblast activity, and could have implications for insulin sensitivity in the skeletal muscle of obese and type 2 diabetic patients.

  6. HSL Attenuates the Follicular Oxidative Stress and Enhances the Hair Growth in ob/ob Mice

    Directory of Open Access Journals (Sweden)

    Takeo Minematsu, PhD

    2013-10-01

    Full Text Available Summary: We demonstrated enhanced hair regeneration following topical administration of N-(3-oxododecanoyl-L-homoserine lactone (HSL in ob/ob mice. The ob/ob mice showed delayed hair regeneration (more than 6 wk after depilation, which rapidly induced transition to anagen in the hair cycle in wild-type mice. Vehicle and HSL solutions were applied to the depilated dorsal skin of ob/ob mice. The depilated skin of the HSL-treated mice was fully covered with hair, whereas no macroscopic alteration was observed in vehicle-treated group by the fourth week after depilation. Oxidative stress was drastically decreased and the expression of the antioxidative enzymes PON1 and PON3 was increased in the HSL-treated skin with highly proliferative anagen follicles. These results suggest that HSL is a candidate therapeutic agent for alopecia in metabolic syndrome.

  7. OBS development and data analysis in Taiwan

    Science.gov (United States)

    Lin, C.; Wang, C.; Chen, P.; Chang, H.; Jang, J.; Kuo, B.

    2012-12-01

    Since 1991 there have been various types of ocean bottom seismometers (OBS) deployed in the waters around Taiwan with different scientific goals. A few years of experiences taught us that many aspects of the instruments can be improved without too much effort. These include extension of deployment time, extension of the recording bandwidth of a short period OBS, and more flexibly to accommodate scientific demands without instrumental overhaul. Scientists will not burden themselves by these tasks, and sending back the instrument to original manufactory for modifications is usually impractical budget-wise, in timeline, and for mission goals. It is thus necessary to develop a sustainable OBS program in Taiwan. Academia Sinica has been collaborating with Taiwan Ocean Research Institute (TORI) and National Sun Yat-sen University (NSYSU) to build a new short-period OBS which has passed a series of tests and have been deployed in the Okinawa trough, Bashi channel, east Korea offshore and on service in Huatung basin. This paper describes the design goal of this OBS, component specification, and reports the preliminary analyses of data and the future directions of instrument development. Keywords: Ocean bottom seismometer, OBS

  8. PHOTOEVAPORATING PROPLYD-LIKE OBJECTS IN CYGNUS OB2

    Energy Technology Data Exchange (ETDEWEB)

    Wright, Nicholas J.; Drake, Jeremy J.; Guarcello, Mario G.; Hora, Joseph L. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Drew, Janet E. [Centre for Astronomy Research, Science and Technology Research Institute, University of Hertfordshire, Hatfield AL10 9AB (United Kingdom); Gutermuth, Robert A. [Department of Astronomy, University of Massachusetts, Amherst, MA (United States); Kraemer, Kathleen E., E-mail: nwright@cfa.harvard.edu [Boston College, Institute for Scientific Research, 140 Commonwealth Avenue, Chestnut Hill, MA 02467 (United States)

    2012-02-20

    We report the discovery of 10 proplyd-like objects in the vicinity of the massive OB association Cygnus OB2. They were discovered in IPHAS H{alpha} images and are clearly resolved in broadband Hubble Space Telescope/Advanced Camera for Surveys, near-IR, and Spitzer mid-IR images. All exhibit the familiar tadpole shape seen in photoevaporating objects such as the Orion proplyds, with a bright ionization front at the head facing the central cluster of massive stars and a tail stretching in the opposite direction. Many also show secondary ionization fronts, complex tail morphologies, or multiple heads. We consider the evidence that these are either proplyds or 'evaporating gaseous globules' (EGGs) left over from a fragmenting molecular cloud, but find that neither scenario fully explains the observations. Typical sizes are 50,000-100,000 AU, larger than the Orion proplyds, but in agreement with the theoretical scaling of proplyd size with distance from the ionizing source. These objects are located at projected separations of {approx}6-14 pc from the OB association, compared to {approx}0.1 pc for the Orion proplyds, but are clearly being photoionized by the {approx}65 O-type stars in Cyg OB2. Central star candidates are identified in near- and mid-IR images, supporting the proplyd scenario, though their large sizes and notable asymmetries are more consistent with the EGG scenario. A third possibility is therefore considered that these are a unique class of photoevaporating partially embedded young stellar objects that have survived the destruction of their natal molecular cloud. This has implications for the properties of stars that form in the vicinity of massive stars.

  9. Neural Network Pruning Algorithm with Penalty OBS Process

    Institute of Scientific and Technical Information of China (English)

    MENG Jiang; WANG Yao-cai; LIU Tao

    2005-01-01

    Aimed at the great computing complexity of optimal brain surgeon (OBS) process, a pruning algorithm with penalty OBS process is presented. Compared with sensitive and regularized methods, the penalty OBS algorithm not only avoids time-consuming defect and low pruning efficiency in OBS process, but also keeps higher generalization and pruning accuracy than Levenberg-Marquardt method.

  10. Ablation of ghrelin receptor in leptin-deficient ob/ob mice has paradoxical effects on glucose homeostasis when compared with ablation of ghrelin in ob/ob mice

    Science.gov (United States)

    The orexigenic hormone ghrelin is important in diabetes because it has an inhibitory effect on insulin secretion. Ghrelin ablation in leptin-deficient ob/ob (Ghrelin(-/-):ob/ob) mice increases insulin secretion and improves hyperglycemia. The physiologically relevant ghrelin receptor is the growth ...

  11. Post-T Tauri Stars in the Nearest OB Association

    CERN Document Server

    Mamajek, E E; Liebert, J; Mamajek, Eric E.; Meyer, Michael R.; Liebert, James

    2002-01-01

    We present results of a spectroscopic survey of X-ray- and proper motion-selected samples of late-type stars in the Lower Cen-Cru (LCC) and Upper Cen-Lup (UCL) subgroups of the nearest OB association: Sco-Cen. The primary goals of the survey are to determine the star-formation history of the OB subgroups, and to assess the frequency of accreting stars in a sample dominated by ``post-T Tauri'' pre-MS stars. We investigate two samples: (1) ACT and TRC proper motion candidates with X-ray counterparts in the ROSAT All-Sky Survey BSC, and (2) G and K-type Hipparcos candidate members (de Zeeuw et al. 1999). We obtained optical spectra of 130 candidates with the MSSSO 2.3-m DBS. Pre-MS stars were identified by (1) strong Li 6707A absorption, (2) subgiant surface gravities, (3) proper motions consistent with Sco-Cen membership, and (4) HRD positions consistent with being pre-MS. We demonstrate that measuring the gravity-sensitive band-ratio of Sr II 4077A to Fe I 4071A is a valuable means of discriminating pre-MS and...

  12. Leptin differentially regulates STAT3 activation in the ob/ob mice adipose mesenchymal stem cells

    Science.gov (United States)

    Leptin-deficient genetically obese ob/ob mice exhibit adipocyte hypertrophy and hyperplasia as well as elevated adipose tissue and systemic inflammation. Studies have shown that multipotent stem cells isolated from adult adipose tissue can differentiate into adipocytes ex vivo and thereby contribute...

  13. Adipose tissue gene expression profiles in ob/ob mice treated with leptin.

    Science.gov (United States)

    Zhang, Wei; Della-Fera, Mary Anne; Hartzell, Diane L; Hausman, Dorothy; Baile, Clifton A

    2008-07-04

    Leptin plays a critical role in regulating body weight, lipid metabolism, apoptosis and microvasculature of adipose tissue. To explore multiple signaling pathways of leptin action on adipose tissue, real-time PCR utilizing TaqMan low-density arrays was performed to compare mRNA expression in adipose tissue of ob/ob mice treated with vehicle or leptin (2.5 microg/d or 10 microg/d) for 14 days via subcutaneous osmotic minipumps. Of the 24 target genes selected for characterization, many were differentially expressed between control ob/ob mice and leptin-treated ob/ob mice. Increases in mRNA expression were found for hormone sensitive lipase (HSL), uncoupling protein 2 (UCP2), adrenergic receptor 3 (ADR3), mitofusin 2 (Mfn2), sirtuin 3 (Sirt3), transcription factor sterol regulatory element binding factor 1 (SREBF1), Bcl-2, Bax, Caspase 3, tumor necrosis factor alpha (TNFalpha), adiponectin and angiopoietin 2 (Ang-2). Decreases in expression were found for stearoyl-coenzyme A desaturase 1 (SCD1), fatty acid synthase (FAS), and retinol binding protein 4 (RBP4). There were no changes in expression of transcription factors involved in adipocyte differentiation (C/EBPalpha, PPARalpha, and PPARgamma). These results confirm that alterations in the expression of specific adipose tissue genes including those associated with the promotion of lipid mobilization, energy dissipation, and apoptosis may mediate leptin-induced fat loss in ob/ob mice.

  14. The MicrOBS study around Taiwan

    Science.gov (United States)

    Liang, C.; Lee, C.

    2007-12-01

    Since 2005, we have managed 16 MicrOBS, designed by the French IFREMER, to study the earthquake and crustal structute around Taiwan. The instrument itself is very light (20 kgs) and easy to operate. This OBS has a measuring period up to 2 weeks in the seafloor. We have conducted the works, aiming to get a better understanding of the ¡§marine¡¨ earthquakes, from the in situ small event to the big earthquake. For example, a study of the seismic gaps in the offshore region becomes workable as compare with the time when we only have the land seismological instruments. We have also used this instrument to obtain a detail study of the gas hydrate and free gas zone. Whenever a large seismic source is available, we then conduct the local and regional crustal studies, such as in the Philippine Sea and South China Sea. In the last 3 years, we have directed 285 deployments of MicrOBS around Taiwan. More than 80 per cent of the natural earthquakes in Taiwan (in an average of about 15,000 events of Mm greater than 2 events per year) were occurred in offshore area. Big earthquakes (i.e. Mm greater than 6) are more often happen in the offshore area than that in the onshore region. Therefore, the tools (MicrOBS and OBS) to measure these ¡§marine¡¨ earthquakes become essential to understand the character and origin of crustal dynamics, particularly in the seismogenic zone.

  15. Very Low Mass Objects in Orion OB1a and b

    Science.gov (United States)

    Walter, Frederick M.; Faherty, Jacqueline K.; Sherry, William H.; Brittain, Sean

    2009-02-01

    We present initial results of a search for the substellar mass population of the Orion OB1 a and b associations, based on a deep optical/near-IR survey. We are complete to about 1 magnitude fainter than the 2MASS survey at K. Global comparison of the K vs. J-K color-magnitude diagram shows an excess of objects with K>14.4 (the substellar limit in Orion OB1b) and 0.8Orion OB1b. Near-IR spectra confirm spectral types near M7, and show the triangular H-band continuum shape associated with young (low gravity) objects. Space densities of these objects exceed a few hundred/deg2 near δ Orionis.

  16. Leptin differentially regulate STAT3 activation in ob/ob mouse adipose mesenchymal stem cells

    Directory of Open Access Journals (Sweden)

    Zhou Zhou

    2012-12-01

    Full Text Available Abstract Background Leptin-deficient ob/ob mice exhibit adipocyte hypertrophy and hyperplasia as well as elevated adipose tissue and systemic inflammation. Multipotent stem cells isolated from adult adipose tissue can differentiate into adipocytes ex vivo and thereby contribute toward increased adipocyte cell numbers, obesity, and inflamm ation. Currently, information is lacking regarding regulation of adipose stem cell numbers as well as leptin-induced inflammation and its signaling pathway in ob/ob mice. Methods Using leptin deficient ob/ob mice, we investigated whether leptin injection into ob/ob mice increases adipose stem cell numbers and adipose tissue inflammatory marker MCP-1 mRNA and secretion levels. We also determined leptin mediated signaling pathways in the adipose stem cells. Results We report here that adipose stem cell number is significantly increased following leptin injection in ob/ob mice and with treatment of isolated stem cells with leptin in vitro. Leptin also up-regulated MCP-1 secretion in a dose- and time-dependent manner. We further showed that increased MCP-1 mRNA levels were due to increased phosphorylation of Signal Transducer and Activator of Transcription 3 (STAT3 Ser727 but not STAT3 Tyr705 phosphorylation, suggesting differential regulation of MCP-1 gene expression under basal and leptin-stimulated conditions in adipose stem cells. Conclusions Taken together, these studies demonstrate that leptin increases adipose stem cell number and differentially activates STAT3 protein resulting in up-regulation of MCP-1 gene expression. Further studies of mechanisms mediating adipose stem cell hyperplasia and leptin signaling in obesity are warranted and may help identify novel anti-obesity target strategies.

  17. Spectroscopy of Intermediate Mass Members of the Orion OB1a and b associations

    Science.gov (United States)

    Walter, Frederick M.; Sherry, William; Kim, Serena; Brittain, Sean

    2010-08-01

    OB associations are ideal sites for probing the formation of low mass stars. There has been little systematic study of the low mass stars in the largest nearby OB association, Orion OB1, aside from the Orion Nebula and σ Ori clusters. In an attempt to map the mass function and its spatial variation from 40 to below 0.01 M_⊙, we have completed a near-IR (JHK) survey of about 18 square degrees in the Orion OB1a and OB1b associations using the CPAPIR camera on the SMARTS/CTIO 1.5m telescope, supplemented by a VRI survey using the Steward Observatory Bok/90Prime and the KPNO 4m/MOSAIC cameras, as well as deep 4m/NEWFIRM images. The photometry reveals thousands of candidate association members. We request time with HYDRA to obtain spectra of the brighter candidate members (V<19), in order to confirm youth and membership from Li abundances, chromospheric activity, and radial velocities.

  18. Structure and Evolution of Nearby OB Associations

    NARCIS (Netherlands)

    Brown, A. G. A.; Bruijne, J. H. J. de; Hoogerwerf, R.; Lub, J.; Le Poole, R. S.; Blaauw, A.

    1997-01-01

    Abstract: We present the first results of a comprehensive census of the stellar content of the nearby OB associations based on Hipparcos positions, proper motions and parallaxes for 12842 candidate member stars distributed over 21 fields on the sky. We use a new method to identify moving groups in t

  19. Synergistic Impairment of Glucose Homeostasis in ob/ob Mice Lacking Functional Serotonin 2C Receptors

    OpenAIRE

    Wade, Jennifer M.; Juneja, Punita; Mackay, Adrienne W.; Graham, James; Havel, Peter J.; Tecott, Laurence H.; Goulding, Evan H.

    2007-01-01

    To investigate how serotonin and leptin interact in the regulation of energy balance and glucose homeostasis, we generated a genetic mouse model, the OB2C mouse, which lacks functional serotonin 2C receptors and the adipocyte hormone leptin. The OB2C mice exhibited a dramatic diabetes phenotype, evidenced by a synergistic increase in serum glucose levels and water intake. The severity of the animals’ diabetes phenotype would not have been predicted from the phenotypic characterization of mice...

  20. Cordyceps militaris alleviates non-alcoholic fatty liver disease in ob/ob mice

    Science.gov (United States)

    Choi, Ha-Neul; Jang, Yang-Hee; Kim, Min-Joo; Seo, Min Jeong; Kang, Byoung Won; Jeong, Yong Kee

    2014-01-01

    BACKGROUND/OBJECTIVES Non-alcoholic fatty liver disease (NAFLD) is becoming an important public health problem as metabolic syndrome and type 2 diabetes have become epidemic. In this study we investigated the protective effect of Cordyceps militaris (C. militaris) against NAFLD in an obese mouse model. MATERIALS/METHODS Four-week-old male ob/ob mice were fed an AIN-93G diet or a diet containing 1% C. militaris water extract for 10 weeks after 1 week of adaptation. Serum glucose, insulin, free fatty acid (FFA), alanine transaminase (ALT), and proinflammatory cytokines were measured. Hepatic levels of lipids, glutathione (GSH), and lipid peroxide were determined. RESULTS Consumption of C. militaris significantly decreased serum glucose, as well as homeostasis model assessment for insulin resistance (HOMA-IR), in ob/ob mice. In addition to lowering serum FFA levels, C. militaris also significantly decreased hepatic total lipids and triglyceride contents. Serum ALT activities and tumor necrosis factor-α (TNF-α) and interleukin-6 (IL-6) levels were reduced by C. militaris. Consumption of C. militaris increased hepatic GSH and reduced lipid peroxide levels. CONCLUSIONS These results indicate that C. militaris can exert protective effects against development of NAFLD, partly by reducing inflammatory cytokines and improving hepatic antioxidant status in ob/ob mice. PMID:24741401

  1. Young Stars in the Cygnus OB2 Association

    Science.gov (United States)

    Hartigan, Patrick; Cleeves, Ilse

    2009-08-01

    Cygnus OB2 is by far the dominant region of massive star formation within 2-3 kpc of the Sun, but its stellar content is almost completely unknown owing to large amounts of visual extinction. Using NEWFIRM last fall we surveyed a large area of over two square degrees centered on the main cluster of O and B stars, and found the central part of the cluster to be teeming with at least several hundred, and probably over a thousand stars with near-IR excesses typical of circumstellar disks. With this proposal we aim to begin the process of acquiring spectral types for the entire sample of IR-excess and X-ray bright stars. This census will lead to masses, ages, and accretion rates for each object. With over 100 O stars, Cyg OB2 dwarfs the young clusters in Orion, and promises to provide a truly unique large sample of young stars that can address many of the major outstanding questions of star formation, such as IMF variations, binarity, triggering, mass segregation, accretion history, and disk evolution in a statistically significant way.

  2. Short-term lenalidomide (Revlimid) administration ameliorates cardiomyocyte contractile dysfunction in ob/ob obese mice.

    Science.gov (United States)

    Li, Linlin; Hua, Yinan; Dong, Maolong; Li, Quan; Smith, Derek T; Yuan, Ming; Jones, Kyla R; Ren, Jun

    2012-11-01

    Lenalidomide is a potent immunomodulatory agent capable of downregulating proinflammatory cytokines such as tumor necrosis factor-α (TNF-α) and upregulating anti-inflammatory cytokines. Lenalidomide has been shown to elicit cardiovascular effects, although its impact on cardiac function remains obscure. This study was designed to examine the effect of lenalidomide on cardiac contractile function in ob/ob obese mice. C57BL lean and ob/ob obese mice were given lenalidomide (50 mg/kg/day, p.o.) for 3 days. Body fat composition was assessed by dual-energy X-ray absorptiometry. Cardiomyocyte contractile and intracellular Ca(2+) properties were evaluated. Expression of TNF-α, interleukin-6 (IL-6), Fas, Fas ligand (FasL), the short-chain fatty acid receptor GPR41, the NFκB regulator IκB, endoplasmic reticulum (ER) stress, the apoptotic protein markers Bax, Bcl-2, caspase-8, tBid, cytosolic cytochrome C, and caspase-12; and the stress signaling molecules p38 and extracellular signal-regulated kinase (ERK) were evaluated by western blot. ob/ob mice displayed elevated serum TNF-α and IL-6 levels, fat composition and glucose intolerance, the effects of which except glucose intolerance and fat composition were attenuated by lenalidomide. Cardiomyocytes from ob/ob mice exhibited depressed peak shortening (PS) and maximal velocity of shortening/relengthening, prolonged time-to-PS and time-to-90% relengthening as well as intracellular Ca(2+) mishandling, which were ablated by lenalidomide. Western blot analysis revealed elevated levels of TNF-α, IL-6, Fas, Bip, Bax, caspase-8, tBid, cleaved caspase-3 caspase-12, cytochrome C, phosphorylation of p38, and ERK in ob/ob mouse hearts, the effects of which with the exception of Bip, Bax, and caspase-12 were alleviated by lenalidomide. Taken together, these data suggest that lenalidomide is protective against obesity-induced cardiomyopathy possibly through antagonism of cytokine/Fas-induced activation of stress signaling and

  3. Bown dwarf and very low mass stars search in orion ob1a and ob1b asociations

    Directory of Open Access Journals (Sweden)

    J. J. Downes

    2006-01-01

    Full Text Available Se presentan los resultados iniciales de la primera b usqueda optica e infrarroja a gran escala de enanas marrones en la regi on de formaci on estelar de Ori on. Las observaciones opticas fueron hechas con el telescopio Schmidt Jurgen Stock y la c amara QUEST-1 del Observatorio Astron omico Nacional de Venezuela y cubren un area de 180 grad2 de los cuales 32grad2, que incluyen una porci on de la subregi on OB1a y la casi totalidad de OB1b, se estudian en este trabajo. Las observaciones en las bandas R e I fueron procesadas mediante una t ecnica de suma de im agenes incrementando las magnitudes l mite a I = 20.5 y R = 21.5 con completitud hasta I = 19.0 y R = 20.0. La fotometr a infrarroja en las bandas J, H and K se obtuvo de la base de datos del sondeo Two Micron All Sky Survey. Observaciones espectrosc opicas de una primera muestra de candidatas, realizadas con HECTOSPEC, permitieron la con rmaci on de 15 estrellas de muy baja masa y 9 enanas marrones.

  4. Analysis list: Kdm4c [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Kdm4c Embryonic fibroblast,Pluripotent stem cell + mm9 http://dbarchive.bioscienced...bc.jp/kyushu-u/mm9/target/Kdm4c.1.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kdm4c.5.tsv http...://dbarchive.biosciencedbc.jp/kyushu-u/mm9/target/Kdm4c.10.tsv http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kdm4c....Embryonic_fibroblast.tsv,http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/colo/Kdm4c

  5. Antidiabetic effect of a novel non-thiazolidinedione PPAR γ/α agonist on ob/ob mice

    Institute of Scientific and Technical Information of China (English)

    Xi HU; Ying FENG; Yu SHEN; Xiao-feng ZHAO; Juan-hong YU; Yu-she YANG; Ying LENG

    2006-01-01

    Aim: To study whether T33, a new synthesized non-thiazolidinedione (TZD) peroxisome proliferator-activated receptor (PPAR) γ/α dual agonist has an antidiabetic effect on ob/ob mice. Methods: Ob/ob mice were treated with 4 mg/kg or 8 mg/kg T33 by gavage for 20 d. Blood glucose levels were measured regularly. An oral glucose tolerance test (OGTT) and an insulin tolerance test (ITT) were preformed on d 8 and d 12, respectively. The levels of insulin, triglyceride and free fatty acid (FFA) in the serum were measured at the end of administration. The intramuscular and liver triglyceride content was also determined. Results: T33 reduced the hyperglycemia, hyperinsulinemia and hyperlipidemia of the ob/ob mice. The OGTT and ITT showed that the insulin resistance state of the ob/ob mice was obviously ameliorated after T33 treatment. After 20 d treatment with 8 mg/kg T33, the triglyceride content in the gastrocnemius muscle decreased significantly. T33 did not have any effect on triglyceride content in the liver, whereas rosiglitazone significantly increased the hepatocyte lipid deposition. Conclusion: The PPARγ/α dual agonist T33 has antidiabetic and insulin-sensitizing effects in ob/ob mice. It has the potential to be a new therapeutic candidate for the treatment of type 2 diabetes.

  6. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lep{sup ob/ob} mice

    Energy Technology Data Exchange (ETDEWEB)

    Sekiya, Motohiro [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Yahagi, Naoya, E-mail: nyahagi-tky@umin.ac.jp [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Laboratory of Molecular Physiology on Energy Metabolism, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Tamura, Yoshiaki; Okazaki, Hiroaki; Igarashi, Masaki; Ohta, Keisuke; Takanashi, Mikio; Kumagai, Masayoshi; Takase, Satoru; Nishi, Makiko; Takeuchi, Yoshinori; Izumida, Yoshihiko; Kubota, Midori; Ohashi, Ken; Iizuka, Yoko [Department of Metabolic Diseases, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Yagyu, Hiroaki [Division of Endocrinology and Metabolism, Department of Medicine, Jichi Medical University, Tochigi 329-0498 (Japan); Gotoda, Takanari [Department of Nephrology and Endocrinology, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Nagai, Ryozo [Department of Cardiovascular Medicine, Graduate School of Medicine, University of Tokyo, Tokyo 113-8655 (Japan); Shimano, Hitoshi; Yamada, Nobuhiro [Advanced Biomedical Applications, Graduate School of Comprehensive Human Sciences, University of Tsukuba, Ibaragi 305-8575 (Japan); and others

    2009-09-25

    It has long been a matter of debate whether the hormone-sensitive lipase (HSL)-mediated lipolysis in pancreatic {beta}-cells can affect insulin secretion through the alteration of lipotoxicity. We generated mice lacking both leptin and HSL (Lep{sup ob/ob}/HSL{sup -/-}) and explored the role of HSL in pancreatic {beta}-cells in the setting of obesity. Lep{sup ob/ob}/HSL{sup -/-} developed elevated blood glucose levels and reduced plasma insulin levels compared with Lep{sup ob/ob}/HSL{sup +/+} in a fed state, while the deficiency of HSL did not affect glucose homeostasis in Lep{sup +/+} background. The deficiency of HSL exacerbated the accumulation of triglycerides in Lep{sup ob/ob} islets, leading to reduced glucose-stimulated insulin secretion. The deficiency of HSL also diminished the islet mass in Lep{sup ob/ob} mice due to decreased cell proliferation. In conclusion, HSL affects insulin secretary capacity especially in the setting of obesity.

  7. Unimpaired thermogenic response to noradrenaline in genetic (ob/ob) and hypothalamic (MSG) obese mice.

    Science.gov (United States)

    Duloo, A G; Miller, D S

    1984-04-01

    The thermogenic response to noradrenaline administration was investigated at 25 degrees C in two models of obese mice (genetic ob/ob obesity of the ' QEC ' strain and monosodium-glutamate-induced obesity) and in their respective lean littermates. Subcutaneous injections of a low dose of noradrenaline (100 micrograms/kg body wt.) elevated metabolic rate by about 30% in both obese models but not in their respective lean counterparts. In contrast, the increase in metabolic rate after injections of a high dose of noradrenaline (600 micrograms/kg body wt.) was of a similar magnitude in both lean and obese animals: metabolic rate was increased by 70-80%. These results indicate that the overall whole body thermogenic capacity is unimpaired at room temperature in this ' QEC ' strain of ob/ob mice and in the hypothalamic damaged obese mice. Obesity in these models is therefore not associated with a reduced ability to respond to noradrenaline but could rather be due to a failure to release noradrenaline.

  8. A Fresh Catch of Massive Binaries in the Cygnus OB2 Association

    CERN Document Server

    Kobulnicky, Henry A; Kiminki, Daniel C; Runnoe, Jessie C; Wood, Earl S; Long, Garrett; Alexander, Michael J; Lundquist, Michael J; Vargas-Alvarez, Carlos A

    2012-01-01

    Massive binary stars may constitute a substantial fraction of progenitors to supernovae and gamma-ray bursts, and the distribution of their orbital characteristics holds clues to the formation process of massive stars. As a contribution to securing statistics on OB-type binaries, we report the discovery and orbital parameters for five new systems as part of the Cygnus OB2 Radial Velocity Survey. Four of the new systems (MT070, MT174, MT267, and MT734 (a.k.a. VI Cygni #11) are single-lined spectroscopic binaries while one (MT103) is a double-lined system (B1V+B2V). MT070 is noteworthy as the longest period system yet measured in Cyg OB2, with P=6.2 yr. The other four systems have periods ranging between 4 and 73 days. MT174 is noteworthy for having a probable mass ratio q<0.1, making it a candidate progenitor to a low-mass X-ray binary. These measurements bring the total number of massive binaries in Cyg OB2 to 25, the most currently known in any single cluster or association.

  9. Leptin Administration Downregulates the Increased Expression Levels of Genes Related to Oxidative Stress and Inflammation in the Skeletal Muscle of ob/ob Mice

    Science.gov (United States)

    Sáinz, Neira; Rodríguez, Amaia; Catalán, Victoria; Becerril, Sara; Ramírez, Beatriz; Gómez-Ambrosi, Javier; Frühbeck, Gema

    2010-01-01

    Obese leptin-deficient ob/ob mice exhibit a low-grade chronic inflammation together with a low muscle mass. Our aim was to analyze the changes in muscle expression levels of genes related to oxidative stress and inflammatory responses in leptin deficiency and to identify the effect of in vivo leptin administration. Ob/ob mice were divided in three groups as follows: control ob/ob, leptin-treated ob/ob (1 mg/kg/d) and leptin pair-fed ob/ob mice. Gastrocnemius weight was lower in control ob/ob than in wild type mice (P < .01) exhibiting an increase after leptin treatment compared to control and pair-fed (P < .01) ob/ob animals. Thiobarbituric acid reactive substances, markers of oxidative stress, were higher in serum (P < .01) and gastrocnemius (P = .05) of control ob/ob than in wild type mice and were significantly decreased (P < .01) by leptin treatment. Leptin deficiency altered the expression of 1,546 genes, while leptin treatment modified the regulation of 1,127 genes with 86 of them being involved in oxidative stress, immune defense and inflammatory response. Leptin administration decreased the high expression of Crybb1, Hspb3, Hspb7, Mt4, Cat, Rbm9, Serpinc1 and Serpinb1a observed in control ob/ob mice, indicating that it improves inflammation and muscle loss. PMID:20671928

  10. Preliminary results of the Source China Sea passive source OBS array experiment

    Science.gov (United States)

    Yang, T.; Liu, C.; Pei, Y.; Xia, S.

    2013-12-01

    The Scarborough, or Huangyan, Seamount chain in South China Sea (SCS) represents an extreme case of the global mid-ocean ridge system where the magmatism continues for many million years after the cessation of spreading. To understand this unique process, the South China Sea Deep (SCSD) program funded an experiment deploying a passive source OBS array to image the lithospheric structure beneath the extinct ridge. In April 2012, 18 passive source OBSs, including 15 Guralp CMG-40T OBS and 3 I-4C OBS, were deployed around the Huangyan Island for one year. 11 OBSs were successfully recovered this April, and their data are being processed. Here we present some preliminary results from analyses of this dataset, including the general quality of three-component seismograms, characteristics of seafloor ambient noise spectra, determining the OBS orientation from the Rayleigh wave polarization, and the dispersion analysis of Rayleigh waves. We found that, for most stations, seismograms from teleseismic, regional and local events are generally good with the horizontal records being comparable with vertical component. The noise levels in these seafloor stations are much higher than land-based stations, especially in shorter periods, likely suggesting the direct and stronger impact from the tempestuous SCS. Applications of more sophisticated seismic techniques such as surface wave tomography, seismic anisotropy, receiver function and ambient noise cross-correlation are underway. In addition to the low recovery rate, there are other lessons learned from this experiment. For example, at least two stations have detectable timing problems; Airgun shots should have been used to constrain the timings and orientations in both deployment and recovery. It is still challenging and costly to carry out long-term passive source seismic observations in deep sea.

  11. TNF-alpha is required for the attraction of mesenchymal precursors to white adipose tissue in Ob/ob mice.

    Directory of Open Access Journals (Sweden)

    Beatriz G Gálvez

    Full Text Available Most adult tissues harbour a stem cell subpopulation (Mesenchymal Precursors or MPs that represent a small proportion of the total cell number and have the potential to differentiate into several cell types within the mesenchymal lineage. In adipose tissue, adipocytes account for two-thirds of the total cell number. The remaining cells include blood and endothelial cells, along with adipocyte precursors (adipose MPs. Obesity is defined as an excess of body fat that frequently results in a significant impairment of health. The ob/ob mice bear a mutation in the ob gene that causes a deficiency in the hormone leptin and hence obesity. Here, we present evidence that ob/ob mice have a dramatic decrease in the resident MP pool of several tissues, including squeletal muscle, heart, lung and adipose tissue. Moreover, we show that that there is a migration of MP cells from distant organs, as well as homing of these cells to the adipose tissue mass of the ob/ob mice. We call this process adipotaxis. Once in the adipose tissue, migrant MPs undergoe adipose differentiation, giving rise to new differentiated adipocytes within the adipose mass. Finally, we provide evidence that adipotaxis is largely explained by the production of high levels of Tumor Necrosis Factor-alpha (TNF-alpha within the ob/ob adipose tissue. The therapeutic implications for human obesity as well as for regenerative medicine are further discussed in this paper.

  12. Open clusters in Auriga OB2

    Science.gov (United States)

    Marco, Amparo; Negueruela, Ignacio

    2016-06-01

    We study the area around the H II region Sh 2-234, including the young open cluster Stock 8, to investigate the extent and definition of the association Aur OB2 and the possible role of triggering in massive cluster formation. We obtained Strömgren and J, H, KS photometry for Stock 8 and Strömgren photometry for two other cluster candidates in the area, which we confirm as young open clusters and name Alicante 11 and Alicante 12. We took spectroscopy of ˜33 early-type stars in the area, including the brightest cluster members. We calculate a common distance of 2.80^{+0.27}_{-0.24} kpc for the three open clusters and surrounding association. We derive an age 4-6 Ma for Stock 8, and do not find a significantly different age for the other clusters or the association. The star LS V +34°23, with spectral type O8 II(f), is likely the main source of ionization of Sh 2-234. We observe an important population of pre-main-sequence stars, some of them with discs, associated with the B-type members lying on the main sequence. We interpret the region as an area of recent star formation with some residual and very localized ongoing star formation. We do not find evidence for sequential star formation on a large scale. The classical definition of Aur OB2 has to be reconsidered, because its two main open clusters, Stock 8 and NGC 1893, are not at the same distance. Stock 8 is probably located in the Perseus arm, but other nearby H II regions whose distances also place them in this arm show quite different distances and radial velocities and, therefore, are not connected.

  13. Deflection routing scheme for GMPLS-based OBS networks

    DEFF Research Database (Denmark)

    Eid, Arafat; Mahmood, Waqar; Alomar, Anwar;

    2010-01-01

    Integrating the Generalized Multi-Protocol Label Switching (GMPLS) framework into an Optical Burst Switching (OBS) Control Plane is a promising solution to alleviating most of OBS performance and design issues. However, implementing the already proposed OBS deflection routing schemes is not appli......Integrating the Generalized Multi-Protocol Label Switching (GMPLS) framework into an Optical Burst Switching (OBS) Control Plane is a promising solution to alleviating most of OBS performance and design issues. However, implementing the already proposed OBS deflection routing schemes...... is not applicable in such an integrated solution. This is due to the existence of already established Label Switched Paths (LSPs) between edge nodes in a GMPLS-based OBS network which guide the Data Burst Headers (DBHs) through the network. In this paper we propose a novel deflection routing scheme which can...... be implemented in GMPLS-based OBS Control Plane. In this scheme, deflection routes or LSPs are designed and pre-established for the whole network. The ingress nodes are responsible for enabling DBHs for deflection at contending core ports prior to DBHs transmission. Moreover, we propose an object extension...

  14. Odor-Induced Neuronal Rhythms in the Olfactory Bulb Are Profoundly Modified in ob/ob Obese Mice

    Science.gov (United States)

    Chelminski, Yan; Magnan, Christophe; Luquet, Serge H.; Everard, Amandine; Meunier, Nicolas; Gurden, Hirac; Martin, Claire

    2017-01-01

    Leptin, the product of the Ob(Lep) gene, is a peptide hormone that plays a major role in maintaining the balance between food intake and energy expenditure. In the brain, leptin receptors are expressed by hypothalamic cells but also in the olfactory bulb, the first central structure coding for odors, suggesting a precise function of this hormone in odor-evoked activities. Although olfaction plays a key role in feeding behavior, the ability of the olfactory bulb to integrate the energy-related signal leptin is still missing. Therefore, we studied the fate of odor-induced activity in the olfactory bulb in the genetic context of leptin deficiency using the obese ob/ob mice. By means of an odor discrimination task with concomitant local field potential recordings, we showed that ob/ob mice perform better than wild-type (WT) mice in the early stage of the task. This behavioral gain of function was associated in parallel with profound changes in neuronal oscillations in the olfactory bulb. The distribution of the peaks in the gamma frequency range was shifted toward higher frequencies in ob/ob mice compared to WT mice before learning. More notably, beta oscillatory activity, which has been shown previously to be correlated with olfactory discrimination learning, was longer and stronger in expert ob/ob mice after learning. Since oscillations in the olfactory bulb emerge from mitral to granule cell interactions, our results suggest that cellular dynamics in the olfactory bulb are deeply modified in ob/ob mice in the context of olfactory learning.

  15. Enhanced glucose cycling and suppressed de novo synthesis of glucose-6-phosphate result in a net unchanged hepatic glucose output in ob/ob mice

    NARCIS (Netherlands)

    Bandsma, RHJ; Grefhorst, A; van Dijk, TH; van der Sluijs, FH; Hammer, A; Reijngoud, DJ; Kuipers, F

    2004-01-01

    Aims/hypothesis. Leptin-deficient ob/ob mice are hyperinsulinaemic and hyperglycaemic; however, the cause of hyperglycaemia remains largely unknown. Methods. Glucose metabolism in vivo in 9-h fasted ob/ob mice and lean littermates was studied by infusing [U-C-13]-glucose, [2-C-13]-glycerol, [1-H-2]-

  16. Leptin Increases Striatal Dopamine D2 Receptor Binding in Leptin-Deficient Obese (ob/ob) Mice

    Energy Technology Data Exchange (ETDEWEB)

    Pfaffly, J.; Michaelides, M.; Wang, G-J.; Pessin, J.E.; Volkow, N.D.; Thanos, P.K.

    2010-06-01

    Peripheral and central leptin administration have been shown to mediate central dopamine (DA) signaling. Leptin-receptor deficient rodents show decreased DA D2 receptor (D2R) binding in striatum and unique DA profiles compared to controls. Leptin-deficient mice show increased DA activity in reward-related brain regions. The objective of this study was to examine whether basal D2R-binding differences contribute to the phenotypic behaviors of leptin-deficient ob/ob mice, and whether D2R binding is altered in response to peripheral leptin treatment in these mice. Leptin decreased body weight, food intake, and plasma insulin concentration in ob/ob mice but not in wild-type mice. Basal striatal D2R binding (measured with autoradiography [{sup 3}H] spiperone) did not differ between ob/ob and wild-type mice but the response to leptin did. In wild-type mice, leptin decreased striatal D2R binding, whereas, in ob/ob mice, leptin increased D2R binding. Our findings provide further evidence that leptin modulates D2R expression in striatum and that these effects are genotype/phenotype dependent.

  17. OB protein binds specifically to the choroid plexus of mice and rats.

    Science.gov (United States)

    Devos, R; Richards, J G; Campfield, L A; Tartaglia, L A; Guisez, Y; van der Heyden, J; Travernier, J; Plaetinck, G; Burn, P

    1996-05-28

    Binding studies were conducted to identify the anatomical location of brain target sites for OB protein, the ob gene product. 125I-labeled recombinant mouse OB protein or alkaline phosphatase-OB fusion proteins were used for in vitro and in vivo binding studies. Coronal brain sections or fresh tissue from lean, obese ob/ob, and obese db/db mice as well as lean and obese Zucker rats were probed to identify potential central OB protein-binding sites. We report here that recombinant OB protein binds specifically to the choroid plexus. The binding of OB protein (either radiolabeled or the alkaline phosphatase-OB fusion protein) and its displacement by unlabeled OB protein was similar in lean, obese ob/ob, and obese db/db mice as well as lean and obese Zucker rats. These findings suggest that OB protein binds with high affinity to a specific receptor in the choroid plexus. After binding to the choroid plexus receptor, OB protein may then be transported across the blood-brain barrier into the cerebrospinal fluid. Alternatively, binding of OB protein to a specific receptor in the choroid plexus may activate afferent neural inputs to the neural network that regulates feeding behavior and energy balance or may result in the clearance or degradation of OB protein. The identification of the choroid plexus as a brain binding site for OB protein will provide the basis for the construction of expression libraries and facilitate the rapid cloning of the choroid plexus OB receptor.

  18. Coordinated regulation of the ESCRT-III component CHMP4C by the chromosomal passenger complex and centralspindlin during cytokinesis

    Science.gov (United States)

    Capalbo, Luisa; Mela, Ioanna; Abad, Maria Alba; Jeyaprakash, A. Arockia; Edwardson, J. Michael

    2016-01-01

    The chromosomal passenger complex (CPC)—composed of Aurora B kinase, Borealin, Survivin and INCENP—surveys the fidelity of genome segregation throughout cell division. The CPC has been proposed to prevent polyploidy by controlling the final separation (known as abscission) of the two daughter cells via regulation of the ESCRT-III CHMP4C component. The molecular details are, however, still unclear. Using atomic force microscopy, we show that CHMP4C binds to and remodels membranes in vitro. Borealin prevents the association of CHMP4C with membranes, whereas Aurora B interferes with CHMP4C's membrane remodelling activity. Moreover, we show that CHMP4C phosphorylation is not required for its assembly into spiral filaments at the abscission site and that two distinctly localized pools of phosphorylated CHMP4C exist during cytokinesis. We also characterized the CHMP4C interactome in telophase cells and show that the centralspindlin complex associates preferentially with unphosphorylated CHMP4C in cytokinesis. Our findings indicate that gradual dephosphorylation of CHMP4C triggers a ‘relay’ mechanism between the CPC and centralspindlin that regulates the timely distribution and activation of CHMP4C for the execution of abscission. PMID:27784789

  19. Mass loss rate determinations of southern OB stars

    CERN Document Server

    Benaglia, P; Koribalski, B S

    2001-01-01

    A sample of OB stars (eleven Of, one O and one B supergiant) has been surveyed with the Australia Telescope Compact Array at 4.8 and 8.64 GHz with a resolution of 2'' -- 4''. Five stars were detected; three of them have negative spectral indices, consistent with non-thermal emission, and two have positive indices. The thermal radiation from HD 150135 and HD 163181 can be explained as coming from an optically thick ionized stellar wind. The non-thermal radiation from CD-47 4551, HD 124314 and HD 150136 possibly comes from strong shocks in the wind itself and/or in the wind colliding region if the stars have a massive early-type companion. The percentage of non-thermal emitters among detected O stars has increased up to ~50%. The Of star HD 124314 clearly shows flux density variations. Mass loss rates (or upper limits) were derived for all the observed stars and the results compared with non-radio measurements and theoretical predictions.

  20. Spatial Distribution and Kinematics of OB Stars

    CERN Document Server

    Gontcharov, George

    2016-01-01

    The sample of 37 485 suspected OB stars selected by Gontcharov (2008) from the Tycho-2 catalogue has been cleaned of the stars that are not of spectral types OV--A0V. For this purpose, the apparent magnitude $V_T$ from Tycho-2, the absolute magnitude $M_{V_T}$ calibrated as a function of the dereddened color index $(B_T-V_T)_0$, the interstellar extinction $A_{V_T}$ calculated from the 3D analytical model by Gontcharov (2009) as a function of the Galactic coordinates, and the photometric distance $r_{ph}$ calculated as a function of $V_T$, $M_{V_T}$, and $A_{V_T}$ have been reconciled in an iterative process. The 20 514 stars that passed the iterations have $(B_T-V_T)_0-5$ and are considered as a sample of OV--A0V stars complete within 350 pc of the Sun. Based on the theoretical relation between the dereddened color and age of the stars, the derived sample has been divided into three subsamples: $(B_T-V_T)_0<-0.2^m$, $-0.2^m<(B_T-V_T)_0<-0.1^m$, and $-0.1^m<(B_T-V_T)_0<0^m$, younger than 100, $...

  1. Open clusters in AurOB2

    CERN Document Server

    Marco, A

    2016-01-01

    We study the area around the HII region Sh 2-234, including the young open cluster Stock 8, to investigate the extent and definition of the association Aur OB2 and the possible role of triggering in massive cluster formation. We obtained Str\\"omgren and J,H,Ks photometry for Stock 8 and Str\\"omgren photometry for two other cluster candidates in the area, which we confirm as young open clusters and name Alicante 11 and Alicante 12. We took spectroscopy of 33 early-type stars in the area, including the brightest cluster members. We calculate a common distance of $2.80^{+0.27}_{-0.24}$ kpc for the three open clusters and surrounding association. We derive an age 4-6 Ma for Stock 8, and do not find a significantly different age for the other clusters or the association. The star LSV +34 23, with spectral type O8 II(f), is likely the main source of ionization of Sh 2-234. We observe an important population of pre-main sequence stars, some of them with disks, associated with the B-type members lying on the main-seq...

  2. Strömgren and Hß photometry of O and B type stars in star-forming regions. II. Moneceros OB2, Canis Major OB1 and Collinder 121

    DEFF Research Database (Denmark)

    Kaltcheva, N.T.; Olsen, Erik Heyn; Clausen, J.V.

    1999-01-01

    Stars: Early-type - Galaxy: Open clusters and associations: Individual: Mon OB2, CMa OB1, Col 121......Stars: Early-type - Galaxy: Open clusters and associations: Individual: Mon OB2, CMa OB1, Col 121...

  3. 4C-ker: A Method to Reproducibly Identify Genome-Wide Interactions Captured by 4C-Seq Experiments.

    Science.gov (United States)

    Raviram, Ramya; Rocha, Pedro P; Müller, Christian L; Miraldi, Emily R; Badri, Sana; Fu, Yi; Swanzey, Emily; Proudhon, Charlotte; Snetkova, Valentina; Bonneau, Richard; Skok, Jane A

    2016-03-01

    4C-Seq has proven to be a powerful technique to identify genome-wide interactions with a single locus of interest (or "bait") that can be important for gene regulation. However, analysis of 4C-Seq data is complicated by the many biases inherent to the technique. An important consideration when dealing with 4C-Seq data is the differences in resolution of signal across the genome that result from differences in 3D distance separation from the bait. This leads to the highest signal in the region immediately surrounding the bait and increasingly lower signals in far-cis and trans. Another important aspect of 4C-Seq experiments is the resolution, which is greatly influenced by the choice of restriction enzyme and the frequency at which it can cut the genome. Thus, it is important that a 4C-Seq analysis method is flexible enough to analyze data generated using different enzymes and to identify interactions across the entire genome. Current methods for 4C-Seq analysis only identify interactions in regions near the bait or in regions located in far-cis and trans, but no method comprehensively analyzes 4C signals of different length scales. In addition, some methods also fail in experiments where chromatin fragments are generated using frequent cutter restriction enzymes. Here, we describe 4C-ker, a Hidden-Markov Model based pipeline that identifies regions throughout the genome that interact with the 4C bait locus. In addition, we incorporate methods for the identification of differential interactions in multiple 4C-seq datasets collected from different genotypes or experimental conditions. Adaptive window sizes are used to correct for differences in signal coverage in near-bait regions, far-cis and trans chromosomes. Using several datasets, we demonstrate that 4C-ker outperforms all existing 4C-Seq pipelines in its ability to reproducibly identify interaction domains at all genomic ranges with different resolution enzymes.

  4. Reverse time migration of multiples for OBS data

    KAUST Repository

    Zhang, Dongliang

    2014-08-05

    Reverse time migration of multiples (RTMM) is applied to OBS data with sparse receiver spacing. RTMM for OBS data unlike a marine streamer acquisition is implemented in the common receiver gathers (CRG) and provides a wider and denser illumination for each CRG than the conventional RTM of primaries. Hence, while the the conventional RTM image contains strong aliasing artifacts due to a sparser receiver interval, the RTMM image suffers from this artifacts less. This benefit of RTMM is demonstrated with numerical test on the Marmousi model for sparsely sampled OBS data.

  5. Variability monitoring of OB stars during the Mons campaign

    CERN Document Server

    Morel, T; Eversberg, T; Alves, F; Arnold, W; Bergmann, T; Viegas, N G Correia; Fahed, R; Fernando, A; Carreira, L F Gouveia; Hunger, T; Knapen, J H; Leadbeater, R; Dias, F Marques; Moffat, A F J; Reinecke, N; Ribeiro, J; Romeo, N; Gallego, J Sanchez; Santos, E M dos; Schanne, L; Stahl, O; Stober, Ba; Stober, Be; Vollmann, K; Corcoran, M F; Dougherty, S M; Hamaguchi, K; Pittard, J M; Pollock, A M T; Williams, P M

    2010-01-01

    We present preliminary results of a 3-month campaign carried out in the framework of the Mons project, where time-resolved Halpha observations are used to study the wind and circumstellar properties of a number of OB stars.

  6. IPHAS discoveries of young stars towards Cyg OB2 and its southern periphery

    CERN Document Server

    Vink, Jorick S; Steeghs, Danny; Wright, Nick J; Martin, Eduardo L; Gaensicke, Boris T; Greimel, Robert; Drake, Jeremy

    2008-01-01

    We report on the discovery of over 50 strong Halpha emitting objects towards the large OB association Cyg OB2 and the HII region DR 15 on its southern periphery. This was achieved using the INT Photometric Halpha Survey of the Northern Galactic Plane (IPHAS), combined with follow-up spectroscopy using the MMT multi-object spectrometer HectoSpec. We present optical spectra, supplemented with optical r', i' and Halpha photometry from IPHAS, and near-infrared J, H, and K photometry from 2MASS. The position of the objects in the (J - H) versus (H - K) diagram strongly suggests most of them are young. Many show CaII IR triplet emission indicating that they are in a pre-main sequence phase of evolution of T Tauri and Herbig Ae nature. Among these, we have uncovered pronounced clustering of T Tauri stars roughly a degree south of the centre of Cyg OB2, in an arc close to the HII region DR 15, and the radio ring nebula G79.29+0.46, for which we discuss its candidacy as a luminous blue variable (LBV). The emission lin...

  7. Brown Adipose Tissue Transplantation Reverses Obesity in Ob/Ob Mice.

    Science.gov (United States)

    Liu, Xiaomeng; Wang, Siping; You, Yilin; Meng, Minghui; Zheng, Zongji; Dong, Meng; Lin, Jun; Zhao, Qianwei; Zhang, Chuanhai; Yuan, Xiaoxue; Hu, Tao; Liu, Lieqin; Huang, Yuanyuan; Zhang, Lei; Wang, Dehua; Zhan, Jicheng; Jong Lee, Hyuek; Speakman, John R; Jin, Wanzhu

    2015-07-01

    Increasing evidence indicates that brown adipose tissue (BAT) transplantation enhances whole-body energy metabolism in a mouse model of diet-induced obesity. However, it remains unclear whether BAT also has such beneficial effects on genetically obese mice. To address this issue, we transplanted BAT from C57/BL6 mice into the dorsal subcutaneous region of age- and sex-matched leptin deficient Ob/Ob mice. Interestingly, BAT transplantation led to a significant reduction of body weight gain with increased oxygen consumption and decreased total body fat mass, resulting in improvement of insulin resistance and liver steatosis. In addition, BAT transplantation increased the level of circulating adiponectin, whereas it reduced the levels of circulating free T3 and T4, which regulate thyroid hormone sensitivity in peripheral tissues. BAT transplantation also increased β3-adrenergic receptor and fatty acid oxidation related gene expression in subcutaneous and epididymal (EP) white adipose tissue. Accordingly, BAT transplantation increased whole-body thermogenesis. Taken together our results demonstrate that BAT transplantation may reduce obesity and its related diseases by activating endogenous BAT.

  8. Preliminary performance report of the RHUM-RUM OBS network

    Science.gov (United States)

    Stähler, Simon C.; Crawford, Wayne; Barruol, Guilhem; Sigloch, Karin; Mechita, Schmidt-Aursch

    2015-04-01

    RHUM-RUM is a German-French seismological experiment based on the seafloor surrounding the hotspot of La Réunion, western Indian Ocean. Its primary objective is to clarify the presence or absence of a mantle plume beneath the Reunion hotspot. RHUM-RUM's central component is a one-year deployment (Oct 2012 - Nov 2013) of 57 broadband ocean-bottom seismometers (OBS) and hydrophones on an area of 2000x2000 km2 surrounding the hotspot. The OBS pool contained 48 instruments from the German DEPAS pool and 9 French stations from INSU. All OBS have been successfully recovered. Preliminary analysis of the seismometer recordings show large differences in long-period (>10s) noise levels between the German and the French OBS. These differences are strongest on the horizontal components and can be probably explained by dynamic tilt of the instrument itself. The noise level of the German instruments is >20dB higher in this period range compared to the French ones. A reason could be that for the German OBS, the seismometer is integrated into the OBS frame and therefore affected by its movement due to currents. The high noise level on the horizontal components will have to be considered in future experiment design, when using this instrument type for three-component waveform tomography.

  9. Signals embedded in the OBS records, in light of Gabor Spectral Analysis

    Science.gov (United States)

    Chang, T.; Wang, Y.; Chang, C.; Lee, C.

    2005-12-01

    Since the last decades, seismological survey has been expanded to marine area, with goal of making up the deficiency of seismogenic study outside the land. Although teleseismic data can resolve plate boundaries location and certain seismic parameters for great earthquake, local seismogenic frame can be merely emerged by the seismic network in situ. The Ocean Bottom Seismometer (OBS), therefore, is developing for this kind of purpose and becoming an important facility for seismological study. This work introduces a synthesized spectral method to analyze the seismograms recorded by 15 OBS deployed at the Okinawa trough in 14 days (Nov. 19 ~Dec. 2, 2003). Geological background of Okinawa trough is well known to correspond with the back-arc spreading in the regime of the Philippine Sea plate subducting northward beneath the Eurasia plate. As the complex affections at sea bottom, for instance, strong current, slope slumping, turbidite flow, and even sea animal attack, the OBS seismogram show a rather noisy sequence in comparison with the record on land. However, hundreds of tectonic earthquake can be extracted from such noisy records (done by Drs. Lin and Sibuet). Our job is to sort out the signals with the distinguishable sources by means of a systematically spectral analysis. The continuous wavelet transform and short-term Fourier transform, both taking Gaussian function as kernel, are synthesized as the Gabor transform in data process. The use of a limited Gaussian window along time axis with negligible low frequency error can largely enhance the stability of discrete Fourier spectrum. With a proper window factor selection, the Gabor transform can improve the resolution of spectrogram in time domain. We have converted the OBS records into spectrograms to detect the variation of signal causes. Up-to-date, some tremors signals and strong current oscillations have been told apart from these continuous records with varied frequency composing. We anticipate the further

  10. The large scale view of the young stellar populations in the Orion OB1 Association

    Science.gov (United States)

    Briceno, Cesar; Calvet, Nuria

    2016-06-01

    The Orion OB1 association, at ~400 pc and with a wide range of ages (~1-10 Myr) and environmental conditions, is an ideal place to look at how stars form, first evolve and disperse among the general population of field stars. Also to study disk dispersal and the duration of the planet formation phase.However, despite spanning nearly 200 deg2 on the sky, almost all we know about Orion comes from studies of a limited fraction of the entire region, mostly of the youngest objects (~B molecular clouds and the ~3 Myr old sigma Ori cluster.We will present here the results of our 180 sq deg photometric multi-epoch survey across the Orion OB1 association, using the known variability of T Tauri stars to pick them among the general field population, and following with spectroscopy to confirm members and characterize them.The ~2000 newly identified young low-mass stars are mostly located away from the molecular clouds, across tens of sq. deg. in the Orion OB1a and OB1b sub-associations, with ages in the range ~4-10 Myr. But within this general population we identify a significant fraction concentrated in distinct overdensities, most notably the ~7 Myr old 25 Orionis cluster. These stellar aggregates point to a previously unknown degree of substructure that has survived the dissipation of the parent molecular clouds. We also find that the Orion Nebula Cluster is surrounded by a few sq.deg. halo of young stars, as has been suggested by recent sudies.

  11. Isomerisation of c4-c6 aldoses with zeolites

    DEFF Research Database (Denmark)

    2014-01-01

    The present invention relates to isomerization of C4-C6 aldoses to their corresponding C4-C6 ketoses. In particular, the invention concerns isomerization of C4-C6 aldoses over solid zeolite catalysts free of any metals other than aluminum, in the presence of suitable solvent(s) at suitable elevated...... temperatures. C6 and C5 aldose sugars such as glucose and xylose, which are available in large amounts from biomass precursors, are isomerized to fructose and xylulose respectively, in a one or two-step process over inexpensive commercially available zeolite catalysts, containing aluminum as the only metal...

  12. Important role of alkali atoms in A4C60

    OpenAIRE

    Gunnarsson, O.; Erwin, S. C.; Koch, E.; Martin, R. M.

    1997-01-01

    We show that hopping via the alkali atoms plays an important role for the t1u band of A4C60 (A=K, Rb), in strong contrast to A3C60. Thus the t1u band is broadened by more than 40 % by the presence of the alkali atoms. The difference between A4C60 and A3C60 is in particular due to the less symmetric location of the alkali atoms in A4C60.

  13. Tumour necrosis factor-α inhibition with lenalidomide alleviates tissue oxidative injury and apoptosis in ob/ob obese mice.

    Science.gov (United States)

    Zhu, Xiaoling; Jiang, Shasha; Hu, Nan; Luo, Fuling; Dong, Hailong; Kang, Yu-Ming; Jones, Kyla R; Zou, Yunzeng; Xiong, Lize; Ren, Jun

    2014-07-01

    Lenalidomide (Revlimid; Selleck Chemicals, Houston, TX, USA), an analogue of thalidomide, possesses potent cytokine modulatory capacity through inhibition of cytokines such as tumour necrosis factor (TNF)-α, a cytokine pivotal for the onset and development of complications in obesity and diabetes mellitus. The present study was designed to evaluate the effect of lenalidomide on oxidative stress, protein and DNA damage in multiple organs in an ob/ob murine model of obesity. To this end, C57BL/6 lean and ob/ob obese mice were administered lenalidomide (50 mg/kg per day, p.o.) for 5 days. Oxidative stress, protein and DNA damage were assessed using the conversion of reduced glutathione (GSH) to oxidized glutathione (GSSG), carbonyl formation and Comet assay, respectively. Apoptosis was evaluated using caspase 3 activity, and levels of Bax, Bcl-2, Bip, caspase 8, caspase 9 and TNF-α were assessed using western blot analysis. Lenalidomide treatment did not affect glucose clearance in lean or ob/ob mice. Obese mice exhibited a reduced GSH/GSSG ratio in the liver, gastrocnemius skeletal muscle and small intestine, as well as enhanced protein carbonyl formation, DNA damage and caspase 3 activity in the liver, kidney, skeletal muscle and intestine; these effects were alleviated by lenalidomide, with the exception of obesity-associated DNA damage in the liver and kidney. Western blot analysis revealed elevated TNF-α, Bax, Bcl-2, Bip, caspase 8 and caspase 9 in ob/ob mice with various degrees of reversal by lenalidomide treatment. Together, these data indicate that lenalidomide protects against obesity-induced tissue injury and protein damage, possibly in association with antagonism of cytokine production and cytokine-induced apoptosis and oxidative stress.

  14. Carnosine Attenuates the Development of both Type 2 Diabetes and Diabetic Nephropathy in BTBR ob/ob Mice

    Science.gov (United States)

    Albrecht, Thomas; Schilperoort, Maaike; Zhang, Shiqi; Braun, Jana D.; Qiu, Jiedong; Rodriguez, Angelica; Pastene, Diego O.; Krämer, Bernhard K.; Köppel, Hannes; Baelde, Hans; de Heer, Emile; Anna Altomare, Alessandra; Regazzoni, Luca; Denisi, Alessandra; Aldini, Giancarlo; van den Born, Jacob; Yard, Benito A.; Hauske, Sibylle J.

    2017-01-01

    We previously demonstrated that polymorphisms in the carnosinase-1 gene (CNDP1) determine the risk of nephropathy in type 2 diabetic patients. Carnosine, the substrate of the enzyme encoded by this gene, is considered renoprotective and could possibly be used to treat diabetic nephropathy (DN). In this study, we examined the effect of carnosine treatment in vivo in BTBR (Black and Tan, BRachyuric) ob/ob mice, a type 2 diabetes model which develops a phenotype that closely resembles advanced human DN. Treatment of BTBR ob/ob mice with 4 mM carnosine for 18 weeks reduced plasma glucose and HbA1c, concomitant with elevated insulin and C-peptide levels. Also, albuminuria and kidney weights were reduced in carnosine-treated mice, which showed less glomerular hypertrophy due to a decrease in the surface area of Bowman’s capsule and space. Carnosine treatment restored the glomerular ultrastructure without affecting podocyte number, resulted in a modified molecular composition of the expanded mesangial matrix and led to the formation of carnosine-acrolein adducts. Our results demonstrate that treatment with carnosine improves glucose metabolism, albuminuria and pathology in BTBR ob/ob mice. Hence, carnosine could be a novel therapeutic strategy to treat patients with DN and/or be used to prevent DN in patients with diabetes. PMID:28281693

  15. Boron carbide (B4C) coating. Deposition and testing

    Science.gov (United States)

    Azizov, E.; Barsuk, V.; Begrambekov, L.; Buzhinsky, O.; Evsin, A.; Gordeev, A.; Grunin, A.; Klimov, N.; Kurnaev, V.; Mazul, I.; Otroshchenko, V.; Putric, A.; Sadovskiy, Ya.; Shigin, P.; Vergazov, S.; Zakharov, A.

    2015-08-01

    Boron carbide was proposed as a material of in-situ protecting coating for tungsten tiles of ITER divertor. To prove this concept the project including investigation of regimes of plasma deposition of B4C coating on tungsten and tests of boron carbide layer in ITER-like is started recently. The paper contends the first results of the project. The results of B4C coating irradiation by the plasma pulses of QSPU-T plasma accelerator are presented. The new device capable of B4C film deposition on tungsten and testing of the films and materials with ITER-like heat loads and ion- and electron irradiation is described. The results of B4C coating deposition and testing of both tungsten substrate and coating are shown and discussed.

  16. The Orion OB1 Association II. The Orion-Eridanus Bubble

    OpenAIRE

    Brown, A. G. A.; Hartmann, D; Burton, W. B.

    1995-01-01

    Observations of the interstellar medium in the vicinity of the Orion OB1 association show a cavity filled with hot ionized gas, surrounded by an expanding shell of neutral hydrogen (the Orion-Eridanus Bubble). In this paper we examine this cavity and the surrounding bubble with the aid of data from the Leiden/Dwingeloo HI survey. We present neutral-hydrogen maps for the Orion-Eridanus region which allow identification of the HI filaments and arcs delineating the Bubble and derivation of its e...

  17. Hypothalamic Leptin Gene Therapy Reduces Bone Marrow Adiposity in ob/ob Mice Fed Regular and High-Fat Diets

    Science.gov (United States)

    Lindenmaier, Laurence B.; Philbrick, Kenneth A.; Branscum, Adam J.; Kalra, Satya P.; Turner, Russell T.; Iwaniec, Urszula T.

    2016-01-01

    Low bone mass is often associated with elevated bone marrow adiposity. Since osteoblasts and adipocytes are derived from the same mesenchymal stem cell (MSC) progenitor, adipocyte formation may increase at the expense of osteoblast formation. Leptin is an adipocyte-derived hormone known to regulate energy and bone metabolism. Leptin deficiency and high-fat diet-induced obesity are associated with increased marrow adipose tissue (MAT) and reduced bone formation. Short-duration studies suggest that leptin treatment reduces MAT and increases bone formation in leptin-deficient ob/ob mice fed a regular diet. Here, we determined the long-duration impact of increased hypothalamic leptin on marrow adipocytes and osteoblasts in ob/ob mice following recombinant adeno-associated virus (rAAV) gene therapy. Eight- to 10-week-old male ob/ob mice were randomized into four groups: (1) untreated, (2) rAAV-Lep, (3) rAAV-green fluorescent protein (rAAV-GFP), or (4) pair-fed to rAAV-Lep. For vector administration, mice were injected intracerebroventricularly with either rAAV-leptin gene therapy (rAAV-Lep) or rAAV-GFP (9 × 107 particles) and maintained for 30 weeks. In a second study, the impact of increased hypothalamic leptin levels on MAT was determined in mice fed high-fat diets; ob/ob mice were randomized into two groups and treated with either rAAV-Lep or rAAV-GFP. At 7 weeks post-vector administration, half the mice in each group were switched to a high-fat diet for 8 weeks. Wild-type (WT) controls included age-matched mice fed regular or high-fat diet. High-fat diet resulted in a threefold increase in MAT in WT mice, whereas MAT was increased by leptin deficiency up to 50-fold. Hypothalamic leptin gene therapy increased osteoblast perimeter and osteoclast perimeter with minor change in cancellous bone architecture. The gene therapy decreased MAT levels in ob/ob mice fed regular or high-fat diet to values similar to WT mice fed regular diet. These findings suggest

  18. Wind collisions in three massive stars of Cyg OB2

    CERN Document Server

    Cazorla, Constantin; Rauw, Gregor

    2013-01-01

    Aims: We wish to study the origin of the X-ray emission of three massive stars in the Cyg OB2 association: Cyg OB2 #5, #8A, #12. Methods: To this aim, dedicated X-ray observations from XMM and Swift are used, as well as archival ROSAT and Suzaku data. Results: Our results on Cyg OB2 #8A improve the phase coverage of the orbit and confirm previous studies: the signature of a wind-wind collision is conspicuous. In addition, signatures of a wind-wind collision are also detected in Cyg OB2 #5, but the X-ray emission appears to be associated with the collision between the inner binary and the tertiary component orbiting it with a 6.7yr period, without a putative collision inside the binary. The X-ray properties strongly constrain the orbital parameters, notably allowing us to discard some proposed orbital solutions. To improve the knowledge of the orbit, we revisit the light curves and radial velocity of the inner binary, looking for reflex motion induced by the third star. Finally, the X-ray emission of Cyg OB2 #...

  19. Calorimetric measurements on Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60}

    Energy Technology Data Exchange (ETDEWEB)

    Inaba, Akira; Miyazaki, Yuji [Research Center for Structural Thermodynamics, Graduate School of Science, Osaka University, Toyonaka, Osaka 560-0043 (Japan); Michałowski, Paweł P.; Gracia-Espino, Eduardo; Wågberg, Thomas, E-mail: Thomas.wagberg@physics.umu.se [Department of Physics, Umeå University, S-90187 Umeå (Sweden); Sundqvist, Bertil [Department of Physics, Umeå University, S-90187 Umeå (Sweden); State Key Laboratory for Superhard Materials, Jilin University, Changchun 130012 (China)

    2015-04-28

    We show specific heat data for Na{sub 4}C{sub 60} and Li{sub 4}C{sub 60} in the range 0.4-350 K for samples characterized by Raman spectroscopy and X-ray diffraction. At high temperatures, the two different polymer structures have very similar specific heats both in absolute values and in general trend. The specific heat data are compared with data for undoped polymeric and pristine C{sub 60}. At high temperatures, a difference in specific heat between the intercalated and undoped C{sub 60} polymers of 100 J K{sup −1} mol{sup −1} is observed, in agreement with the Dulong-Petit law. At low temperatures, the specific heat data for Li{sub 4}C{sub 60} and Na{sub 4}C{sub 60} are modified by the stiffening of vibrational and librational molecular motion induced by the polymer bonds. The covalent twin bonds in Li{sub 4}C{sub 60} affect these motions to a somewhat higher degree than the single intermolecular bonds in Na{sub 4}C{sub 60}. Below 1 K, the specific heats of both materials become linear in temperature, as expected from the effective dimensionality of the structure. The contribution to the total specific heat from the inserted metal ions can be well described by Einstein functions with T{sub E} = 386 K for Li{sub 4}C{sub 60} and T{sub E} = 120 K for Na{sub 4}C{sub 60}, but for both materials we also observe a Schottky-type contribution corresponding to a first approximation to a two-level system with ΔE = 9.3 meV for Li{sub 4}C{sub 60} and 3.1 meV for Na{sub 4}C{sub 60}, probably associated with jumps between closely spaced energy levels inside “octahedral-type” ionic sites. Static magnetic fields up to 9 T had very small effects on the specific heat below 10 K.

  20. Increasing the number and signal-to-noise ratio of OBS traces with supervirtual refraction interferometry and free-surface multiples

    KAUST Repository

    Bharadwaj, P.

    2013-01-10

    The theory of supervirtual interferometry is modified so that free-surface related multiple refractions can be used to enhance the signal-to-noise ratio (SNR) of primary refraction events by a factor proportional to√Ns, where Ns is the number of post-critical sources for a specified refraction multiple. We also show that refraction multiples can be transformed into primary refraction events recorded at virtual hydrophones located between the actual hydrophones. Thus, data recorded by a coarse sampling of ocean bottom seismic (OBS) stations can be transformed, in principle, into a virtual survey with P times more OBS stations, where P is the order of the visible free-surface related multiple refractions. The key assumption is that the refraction arrivals are those of head waves, not pure diving waves. The effectiveness of this method is validated with both synthetic OBS data and an OBS data set recorded offshore from Taiwan. Results show the successful reconstruction of far-offset traces out to a source-receiver offset of 120 km. The primary supervirtual traces increase the number of pickable first arrivals from approximately 1600 to more than 3100 for a subset of the OBS data set where the source is only on one side of the recording stations. In addition, the head waves associated with the first-order free-surface refraction multiples allow for the creation of six new common receiver gathers recorded at virtual OBS station located about half way between the actual OBS stations. This doubles the number of OBS stations compared to the original survey and increases the total number of pickable traces from approximately 1600 to more than 6200. In summary, our results with the OBS data demonstrate that refraction interferometry can sometimes more than quadruple the number of usable traces, increase the source-receiver offsets, fill in the receiver line with a denser distribution of OBS stations, and provide more reliable picking of first arrivals. Apotential liability

  1. Obs4MIPS: Satellite Observations for Model Evaluation

    Science.gov (United States)

    Ferraro, R.; Waliser, D. E.; Gleckler, P. J.

    2015-12-01

    This poster will review the current status of the obs4MIPs project, whose purpose is to provide a limited collection of well-established and documented datasets for comparison with Earth system models (https://www.earthsystemcog.org/projects/obs4mips/). These datasets have been reformatted to correspond with the CMIP5 model output requirements, and include technical documentation specifically targeted for their use in model output evaluation. There are currently over 50 datasets containing observations that directly correspond to CMIP5 model output variables. We will review recent additions to the obs4MIPs collection, and provide updated download statistics. We will also provide an update on changes to submission and documentation guidelines, the work of the WCRP Data Advisory Council (WDAC) Observations for Model Evaluation Task Team, and engagement with the CMIP6 MIP experiments.

  2. e-MERLIN 21cm constraints on the mass-loss rates of OB stars in Cyg OB2

    CERN Document Server

    Morford, Jack; Prinja, Raman; Blomme, Ronnie; Yates, Jeremy

    2016-01-01

    We present e-MERLIN 21 cm (L-band) observations of single luminous OB stars in the Cygnus OB2 association, from the COBRaS Legacy programme. The radio observations potentially offer the most straightforward, least model-dependent, determinations of mass-loss rates, and can be used to help resolve current discrepancies in mass-loss rates via clumped and structured hot star winds. We report here that the 21 cm flux densities of O3 to O6 supergiant and giant stars are less than ~ 70 microJy. These fluxes may be translated to `smooth' wind mass-loss upper limits of ~ 4.4 - 4.8 x 10^(-6) M_sol/yr for O3 supergiants and < 2.9 x 10^(-6) M_sol/yr for B0 to B1 supergiants. The first ever resolved 21 cm detections of the hypergiant (and LBV candidate) Cyg OB2 #12 are discussed; for multiple observations separated by 14 days, we detect a ~ 69% increase in its flux density. Our constraints on the upper limits for the mass-loss rates of evolved OB stars in Cyg OB2 support the model that the inner wind region close to t...

  3. LiFePO_4/C via fluoride doping

    Institute of Scientific and Technical Information of China (English)

    2012-01-01

    Non-stoichiometric compound fluoride-doped LiFePO4/C cathode materials were synthesized via solid-state reaction using MgF2 and AlF3 as dopant. The fluoride-doped LiFePO4/C samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), and electrochemical testing. The results show that the materials are well crystallized and fluoride doping cannot change the space structure of LiFePO4. Slight amounts of Fe2O3 with no fluoride impurity were ...

  4. Variable time-period optical switching: a novel OBS implementation

    Institute of Scientific and Technical Information of China (English)

    Jinsong Zhang(张劲松); Mingcui Cao(曹明翠); Fengguang Luo(罗风光); Tao Chen(陈涛)

    2003-01-01

    In this paper, we proposed a novel optical switching method based on optical burst switching (OBS), we call it variable time-period optical switching (VTPOS). It can both support circuit services and other immerged packet services. It has better usability of bandwidth, shorter offset and latency time than others of unidirectional transport signaling mechanisms for OBS. It supports deflection switching for improve blocking performance without the need of schedule buffer. It introduces a time pointer and phase indicator that made synchronous more precisely and requires less guard time, it also classifies the different services classes with a relative QoS model.

  5. A zero burst loss architecture for star OBS networks

    OpenAIRE

    Mountrouidou, Xenia; Puttasubbappa, Vishwas; Perros, Harry

    2006-01-01

    Performance studies point to the fact that in an OBS network, the link utilization has to be kept very low in order for the burst loss probability to be within an acceptable level. Various congestion control schemes have been proposed, such as the use of converters, fiber delay lines, and deflection routing. However, these schemes do not alleviate this problem. It is our position that in order for OBS to become commercially viable, new schemes have to be devised that will either guarantee zer...

  6. O2CC6H4C6H4CO2(SnPh32∙4H2O AND HO2CC6H4C6H4CO2SnBu2Cl: SYNTHESIS AND INFRARED STUDY

    Directory of Open Access Journals (Sweden)

    ABDOU MBAYE

    2015-02-01

    Full Text Available When the diphenic acid HO2CC6H4C6H4CO2H is allowed to react with SnBu2Cl2 or SnPh3OH, HO2CC6H4C6H4CO2. SnBu2Cl (A and O2CC6H4C6H4CO2(SnPh32∙4H2O(B were obtained and characterized by infrared spectroscopy. The structures are an infinite chain or an oligomer, the diphenic anion being a monodentate or a monochelating ligand. The environment around the tin centers is trigonal bipyramidal or octahedral.

  7. Syntheses of DNA Duplexes That Contain a N4C-alkyl-N4C Interstrand Cross-Link

    Science.gov (United States)

    Miller, Paul S.

    2011-01-01

    A simple procedure is described for preparing short DNA duplexes that contain a single N4C-alkyl-N4C interstrand cross-link. The synthesis is carried out on an automated DNA synthesizer using standard phosphoramidite chemistry. The cross-link is introduced during the synthesis of the duplex. The method can be used to prepare mg quantities of cross-linked duplexes suitable for physical studies and for the preparation of larger DNA molecules that can be used as substrates to study DNA repair in whole cell extracts and in living cells in culture. PMID:21400705

  8. Secure Optical Internet: A Novel Attack Prevention Mechanism for an OBS node in TCP/OBS Networks

    Directory of Open Access Journals (Sweden)

    K. Muthuraj

    2013-01-01

    Full Text Available Optical Internet has become a strong development and its commercial use is growing rapidly. Due to transparency and virtual sharing infrastructure, they provide ultra-fast data rates with the help of optical burst switching technology, which transmits data in the form of bursts. From the security perspective, one of the OBS nodes in the optical network is compromised, causes the vulnerability. This paper is dealt to identify the vulnerabilities and named as burst hijacking attack and provide the prevention mechanism for the same. The NSFnet 14 nodes and the ns2 simulator with modified nOBS patch is used to simulate and verify the security parameters.

  9. IFN-γ secretion in gut of Ob/Ob mice after vertical sleeve gastrectomy and its function in weight loss mechanism.

    Science.gov (United States)

    Du, Jin-Peng; Wang, Geng; Hu, Chao-Jie; Wang, Qing-Bo; Li, Hui-Qing; Xia, Wen-Fang; Shuai, Xiao-Ming; Tao, Kai-Xiong; Wang, Guo-Bin; Xia, Ze-Feng

    2016-06-01

    Vertical sleeve gastrectomy (VSG) is becoming more and more popular among the world. Despite its dramatic efficacy, however, the mechanism of VSG remains largely undetermined. This study aimed to test interferon (IFN)-γ secretion n of mesenteric lymph nodes in obese mice (ob/ob mice), a model of VSG, and its relationship with farnesoid X receptor (FXR) expression in the liver and small intestine, and to investigate the weight loss mechanism of VSG. The wild type (WT) mice and ob/ob mice were divided into four groups: A (WT+Sham), B (WT+VSG), C (ob/ob+Sham), and D (ob/ob+VSG). Body weight values were monitored. The IFN-γ expression in mesenteric lymph nodes of ob/ob mice pre- and post-operation was detected by flow cytometry (FCM). The FXR expression in the liver and small intestine was detected by Western blotting. The mouse AML-12 liver cells were stimulated with IFN-γ at different concentrations in vitro. The changes of FXR expression were also examined. The results showed that the body weight of ob/ob mice was significantly declined from (40.6±2.7) g to (27.5±3.8) g on the 30th day after VSG (Psecretion of IFN-γ in mesenteric lymph nodes of ob/ob mice than that pre-operation (Psmall intestine after VSG were respectively 0.97±0.07 and 0.84±0.07 fold of GAPDH, which were significantly higher than pre-operative levels of 0.50±0.06 and 0.48±0.06 respectively (Psecretion of mesenteric lymph nodes, which then increases the FXR expression of the liver and small intestine.

  10. Hepatic VLDL production in ob/ob mice is not stimulated by massive de novo lipogenesis but is less sensitive to the suppressive effects of insulin.

    Science.gov (United States)

    Wiegman, Coen H; Bandsma, Robert H J; Ouwens, Margriet; van der Sluijs, Fjodor H; Havinga, Rick; Boer, Theo; Reijngoud, Dirk-Jan; Romijn, Johannes A; Kuipers, Folkert

    2003-05-01

    Type 2 diabetes in humans is associated with increased de novo lipogenesis (DNL), increased fatty acid (FA) fluxes, decreased FA oxidation, and hepatic steatosis. In this condition, VLDL production is increased and resistant to suppressive effects of insulin. The relationships between hepatic FA metabolism, steatosis, and VLDL production are incompletely understood. We investigated VLDL-triglyceride and -apolipoprotein (apo)-B production in relation to DNL and insulin sensitivity in female ob/ob mice. Hepatic triglyceride (5-fold) and cholesteryl ester (15-fold) contents were increased in ob/ob mice compared with lean controls. Hepatic DNL was increased approximately 10-fold in ob/ob mice, whereas hepatic cholesterol synthesis was not affected. Basal rates of hepatic VLDL-triglyceride and -apoB100 production were similar between the groups. Hyperinsulinemic clamping reduced VLDL-triglyceride and -apoB100 production rates by approximately 60% and approximately 75%, respectively, in lean mice but only by approximately 20% and approximately 20%, respectively, in ob/ob mice. No differences in hepatic expression of genes encoding apoB and microsomal triglyceride transfer protein were found. Hepatic expression and protein phosphorylation of insulin receptor and insulin receptor substrate isoforms were reduced in ob/ob mice. Thus, strongly induced hepatic DNL is not associated with increased VLDL production in ob/ob mice, possibly related to differential hepatic zonation of apoB synthesis (periportal) and lipid accumulation (perivenous) and/or relatively low rates of cholesterogenesis. Insulin is unable to effectively suppress VLDL-triglyceride production in ob/ob mice, presumably because of impaired insulin signaling.

  11. Nonspherical supernova remnants. IV - Sequential explosions in OB associations

    Science.gov (United States)

    Tenorio-Tagle, G.; Bodenheimer, P.; Rozyczka, M.

    1987-01-01

    Multisupernova remnants, driven by sequential supernova explosions in OB associations, are modelled by means of two-dimensional hydrodynamical calculations. It is shown that due to the Rayleigh-Taylor instability the remnants quickly evolve into highly irregular structures. A critical evaluation of the multisupernova model as an explanation for supershells is given.

  12. A Hipparcos census of the nearby OB associations

    NARCIS (Netherlands)

    Zeeuw, P. T.; Hoogerwerf, R. D; Bruijne, J. H. J. de; Brown, A. G. A.; Blaauw, A.

    1999-01-01

    Published in: Astron. J. 117 (1999) 354 citations recorded in [Science Citation Index] Abstract: A comprehensive census of the stellar content of the nearby OB associations is presented, based on Hipparcos positions, proper motions, and parallaxes. Moving groups are identified by combining de Bruijn

  13. A Multi-Fiber Spectroscopic Search for Low-mass Young Stars in Orion OB1

    Science.gov (United States)

    Loerincs, Jacqueline; Briceno, Cesar; Calvet, Nuria; Mateo, Mario L.; Hernandez, Jesus

    2017-01-01

    We present here results of a low resolution spectroscopic followup of candidate low-mass pre-main sequence stars in the Orion OB1 association. Our targets were selected from the CIDA Variability Survey of Orion (CVSO), and we used the Michigan/Magellan Fiber Spectrograph (M2FS) on the Magellan Clay 6.5m telescope to obtain spectra of 500 candidate T Tauri stars distributed in seven 0.5 deg diameter fields, adding to a total area of ~5.5 deg2. We identify young stars by looking at the distinctive Hα 6563 Å emission and Lithium Li I 6707 Å absorption features characteristic of young low mass pre-main sequence stars. Furthermore, by measuring the strength of their Hα emission lines, confirmed T Tauri stars can be classified as either Classical T Tauris (CTTS) or Weak-line T Tauris (WTTS), which give indication of whether the star is actively accreting material from a gas and dust disk surrounding the star, which may be the precursor of a planetary system. We confirm a total of 90 T Tauri stars, of which 50% are newly identified young members of Orion; out of the 49 new detections,15 are accreting CTTS, and of these all but one are found in the OB1b sub-region. This result is in line with our previous findings that this region is much younger than the more extended Orion OB1a sub-association. The M2FS results add to our growing census of young stars in Orion, that is allowing us to characterize in a systematic and consistent way the distribution of stellar ages across the entire complex, in order to building a complete picture of star formation in this, one of nearest most active sites of star birth.

  14. MUG-OBS - Multiparameter Geophysical Ocean Bottom System : a new instrumental approach to monitor earthquakes.

    Science.gov (United States)

    hello, yann; Charvis, Philippe; Yegikyan, Manuk; verfaillie, Romain; Rivet, Diane

    2016-04-01

    Real time monitoring of seismic activity is a major issue for early warning of earthquakes and tsunamis. It can be done using regional scale wired nodes, such as Neptune in Canada and in the U.S, or DONET in Japan. Another approach to monitor seismic activity at sea is to deploying repeatedly OBS array like during the amphibious Cascadia Initiative (four time 1-year deployments), the Japanese Pacific Array (broadband OBSs "ocean-bottom broadband dispersion survey" with 2-years autonomy), the Obsismer program in the French Lesser Antilles (eight time 6-months deployments) and the Osisec program in Ecuador (four time 6-months deployments). These autonomous OBSs are self-recovered or recovered using an ROV. These systems are costly including ship time, and require to recover the OBS before to start working on data. Among the most recent alternative we developed a 3/4 years autonomy ocean bottom system with 9 channels (?) allowing the acquisition of different seismic or environmental parameters. MUG-OBS is a free falling instrument rated down to 6000 m. The installation of the sensor is monitored by acoustic commands from the surface and a health bulletin with data checking is recovered by acoustic during the installation. The major innovation is that it is possible to recover the data any time on demand (regularly every 6-months or after a crisis) using one of the 6 data-shuttles released from the surface by acoustic command using a one day fast cruise boat of opportunity. Since sensors stayed at the same location for 3 years, it is a perfect tool to monitor large seismic events, background seismic activity and aftershock distribution. Clock, drift measurement and GPS localization is automatic when the shuttle reaches the surface. For remote areas, shuttles released automatically and a seismic events bulletin is transmitted. Selected data can be recovered by two-way Iridium satellite communication. After a period of 3 years the main station is self-recovered by

  15. A Spitzer view of the giant molecular cloud Mon OB1 East/NGC 2264

    Energy Technology Data Exchange (ETDEWEB)

    Rapson, V. A. [School of Physics and Astronomy, Rochester Institute of Technology, Rochester, NY 14623 (United States); Pipher, J. L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Gutermuth, R. A. [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States); Megeath, S. T.; Allen, T. S. [Lowell Observatory, Flagstaff, AZ 86001 (United States); Myers, P. C. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA 02138 (United States); Allen, L. E., E-mail: var5998@rit.edu [National Optical Astronomy Observatories, Tucson, AZ 85719 (United States)

    2014-10-20

    We present Spitzer 3.6, 4.5, 5.8, 8.0, and 24 μm images of the Mon OB1 East giant molecular cloud, which contains the young star forming region NGC 2264, as well as more extended star formation. With Spitzer data and Two Micron All Sky Survey photometry, we identify and classify young stellar objects (YSOs) with dusty circumstellar disks and/or envelopes in Mon OB1 East by their infrared-excess emission and study their distribution with respect to cloud material. We find a correlation between the local surface density of YSOs and column density of molecular gas as traced by dust extinction that is roughly described as a power law in these quantities. NGC 2264 follows a power-law index of ∼2.7, exhibiting a large YSO surface density for a given gas column density. Outside of NGC 2264 where the surface density of YSOs is lower, the power law is shallower and the region exhibits a larger gas column density for a YSO surface density, suggesting the star formation is more recent. In order to measure the fraction of cloud members with circumstellar disks/envelopes, we estimate the number of diskless pre-main-sequence stars by statistical removal of background star detections. We find that the disk fraction of the NGC 2264 region is 45%, while the surrounding, more distributed regions show a disk fraction of 19%. This may be explained by the presence of an older, more dispersed population of stars. In total, the Spitzer observations provide evidence for heterogenous, non-coeval star formation throughout the Mon OB1 cloud.

  16. ObsPy: A Python Toolbox for Seismology

    Science.gov (United States)

    Wassermann, J. M.; Krischer, L.; Megies, T.; Barsch, R.; Beyreuther, M.

    2013-12-01

    Python combines the power of a full-blown programming language with the flexibility and accessibility of an interactive scripting language. Its extensive standard library and large variety of freely available high quality scientific modules cover most needs in developing scientific processing workflows. ObsPy is a community-driven, open-source project extending Python's capabilities to fit the specific needs that arise when working with seismological data. It a) comes with a continuously growing signal processing toolbox that covers most tasks common in seismological analysis, b) provides read and write support for many common waveform, station and event metadata formats and c) enables access to various data centers, webservices and databases to retrieve waveform data and station/event metadata. In combination with mature and free Python packages like NumPy, SciPy, Matplotlib, IPython, Pandas, lxml, and PyQt, ObsPy makes it possible to develop complete workflows in Python, ranging from reading locally stored data or requesting data from one or more different data centers via signal analysis and data processing to visualization in GUI and web applications, output of modified/derived data and the creation of publication-quality figures. All functionality is extensively documented and the ObsPy Tutorial and Gallery give a good impression of the wide range of possible use cases. ObsPy is tested and running on Linux, OS X and Windows and comes with installation routines for these systems. ObsPy is developed in a test-driven approach and is available under the LGPLv3 open source licence. Users are welcome to request help, report bugs, propose enhancements or contribute code via either the user mailing list or the project page on GitHub.

  17. An anomalous extinction law in the Cep OB3b young cluster: Evidence for dust processing during gas dispersal

    Energy Technology Data Exchange (ETDEWEB)

    Allen, Thomas S.; Prchlik, Jakub J.; Megeath, S. Thomas [University of Toledo, Ritter Astrophysical Observatory, Department of Physics and Astronomy, Toledo, OH 43606 (United States); Gutermuth, Robert A. [Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States); Pipher, Judith L. [Department of Physics and Astronomy, University of Rochester, Rochester, NY 14627 (United States); Naylor, Tim [School of Physics, University of Exeter, Exeter, UK EX4 4QL (United Kingdom); Jeffries, R. D. [Astrophysics Group, School of Physical and Geographical Sciences, Keele University, Keele, Staffordshire, UK ST5 5BG (United Kingdom)

    2014-05-10

    We determine the extinction law through Cep OB3b, a young cluster of 3000 stars undergoing gas dispersal. The extinction is measured toward 76 background K giants identified with MMT/Hectospec spectra. Color excess ratios were determined toward each of the giants using V and R photometry from the literature, g, r, i, and z photometry from the Sloan Digital Sky Survey and J, H, and K{sub s} photometry from the Two Micron All Sky Survey. These color excess ratios were then used to construct the extinction law through the dusty material associated with Cep OB3b. The extinction law through Cep OB3b is intermediate between the R{sub V} = 3.1 and R{sub V} = 5 laws commonly used for the diffuse atomic interstellar medium and dense molecular clouds, respectively. The dependence of the extinction law on line-of-sight A{sub V} is investigated and we find the extinction law becomes shallower for regions with A{sub V} > 2.5 mag. We speculate that the intermediate dust law results from dust processing during the dispersal of the molecular cloud by the cluster.

  18. Diminished Chondrogenesis and Enhanced Osteoclastogenesis in Leptin-Deficient Diabetic Mice (ob/ob) Impair Pathologic, Trauma-Induced Heterotopic Ossification

    Science.gov (United States)

    Agarwal, Shailesh; Loder, Shawn; Li, John; Brownley, Cameron; Peterson, Jonathan R.; Oluwatobi, Eboda; Drake, James; Cholok, David; Ranganathan, Kavitha; Sung, Hsiao Hsin; Goulet, James; Li, Shuli

    2015-01-01

    Diabetic trauma patients exhibit delayed postsurgical wound, bony healing, and dysregulated bone development. However, the impact of diabetes on the pathologic development of ectopic bone or heterotopic ossification (HO) following trauma is unknown. In this study, we use leptin-deficient mice as a model for type 2 diabetes to understand how post-traumatic HO development may be affected by this disease process. Male leptin-deficient (ob/ob) or wild-type (C57BL/6 background) mice aged 6–8 weeks underwent 30% total body surface area burn injury with left hind limb Achilles tenotomy. Micro-CT (μCT) imaging showed significantly lower HO volumes in diabetic mice compared with wild-type controls (0.70 vs. 7.02 mm3, P < 0.01) 9 weeks after trauma. Ob/ob mice showed evidence of HO resorption between weeks 5 and 9. Quantitative real time PCR (qRT-PCR) demonstrated high Vegfa levels in ob/ob mice, which was followed by disorganized vessel growth at 7 weeks. We noted diminished chondrogenic gene expression (SOX9) and diminished cartilage formation at 5 days and 3 weeks, respectively. Tartrate-resistant acid phosphatase stain showed increased osteoclast presence in normal native bone and pathologic ectopic bone in ob/ob mice. Our findings suggest that early diminished HO in ob/ob mice is related to diminished chondrogenic differentiation, while later bone resorption is related to osteoclast presence. PMID:26413838

  19. Photometric Identification of the low-Mass Population of Orion OB1b I: The sigma Ori Cluster

    CERN Document Server

    Sherry, W H; Wolk, S J

    2004-01-01

    We report an optical photometric survey of 0.89 sq. degrees of the Orion OB1b association centered on sigma Ori. This region includes most of the sigma Ori cluster, the highest density region within Orion OB1b. We have developed a statistical procedure to identify the young, low-mass pre-main sequence population of the association. We estimate that the cluster has ~160 members in the mass range (0.2

  20. Navy Officials Justified the MQ-4C Triton Procurement Quantity

    Science.gov (United States)

    2015-09-16

    Naval Air Systems Command internal controls over Triton quantity requirements were effective as they applied to the audit objectives, because Navy...Visit us at www.dodig.mil September 16, 2015 Objective This is the first in a series of audits on the Navy MQ-4C Triton (Triton) Unmanned Aircraft...System (UAS) Program. Our overall objective for the series of audits was to determine whether the Navy effectively managed the Triton UAS

  1. The Orion OB1 association; 2, the Orion-Eridanus bubble

    CERN Document Server

    Brown, A G A; Burton, W B; Brown, Anthony G A; Hartmann, D; Burton, W B

    1995-01-01

    Observations of the interstellar medium in the vicinity of the Orion OB1 association show a cavity filled with hot ionized gas, surrounded by an expanding shell of neutral hydrogen (the Orion-Eridanus Bubble). In this paper we examine this cavity and the surrounding bubble with the aid of data from the Leiden/Dwingeloo HI survey. We present neutral-hydrogen maps for the Orion-Eridanus region which allow identification of the HI filaments and arcs delineating the Bubble and derivation of its expansion velocity. The HI data are compared to X-ray, CO and IRAS 100 micron data. Using models of wind blown bubbles that take the density stratification of the Galactic HI layer into account we show that the stellar winds and supernovae from stars in Orion OB1 can account for the size as well as the expansion velocity of the HI shell. However, density inhomogeneities in the ambient interstellar medium cause significant discrepancies between our model and the observed shell.

  2. iPLA2β deficiency attenuates obesity and hepatic steatosis in ob/ob mice through hepatic fatty-acyl phospholipid remodeling.

    Science.gov (United States)

    Deng, Xiuling; Wang, Jiliang; Jiao, Li; Utaipan, Tanyarath; Tuma-Kellner, Sabine; Schmitz, Gerd; Liebisch, Gerhard; Stremmel, Wolfgang; Chamulitrat, Walee

    2016-05-01

    PLA2G6 or GVIA calcium-independent PLA2 (iPLA2β) is identified as one of the NAFLD modifier genes in humans, and thought to be a target for NAFLD therapy. iPLA2β is known to play a house-keeping role in phospholipid metabolism and remodeling. However, its role in NAFLD pathogenesis has not been supported by results obtained from high-fat feeding of iPLA2β-null (PKO) mice. Unlike livers of human NAFLD and genetically obese rodents, fatty liver induced by high-fat diet is not associated with depletion of hepatic phospholipids. We therefore tested whether iPLA2β could regulate obesity and hepatic steatosis in leptin-deficient mice by cross-breeding PKO with ob/ob mice to generate ob/ob-PKO mice. Here we observed an improvement in ob/ob-PKO mice with significant reduction in serum enzymes, lipids, glucose, insulin as well as improved glucose tolerance, and reduction in islet hyperplasia. The improvement in hepatic steatosis measured by liver triglycerides, fatty acids and cholesterol esters was associated with decreased expression of PPARγ and de novo lipogenesis genes, and the reversal of β-oxidation gene expression. Notably, ob/ob livers contained depleted levels of lysophospholipids and phospholipids, and iPLA2β deficiency in ob/ob-PKO livers lowers the former, but replenished the latter particularly phosphatidylethanolamine (PE) and phosphatidylcholine (PC) that contained arachidonic (AA) and docosahexaenoic (DHA) acids. Compared with WT livers, PKO livers also contained increased PE and PC containing AA and DHA. Thus, iPLA2β deficiency protected against obesity and ob/ob fatty liver which was associated with hepatic fatty-acyl phospholipid remodeling. Our results support the deleterious role of iPLA2β in severe obesity associated NAFLD.

  3. OB stars in the Leading Arm of the Magellanic Stream

    CERN Document Server

    Bidin, C Moni; Mendez, R A; Girard, T M; Vieira, K; Korchagin, V I; van Altena, W F

    2013-01-01

    We present our spectroscopic program aimed to study some new interesting features recently discovered in the Magellanic Cloud System. These were revealed by the spatial distribution of OB-type candidate stars, selected based on UV, optical and IR photometry and proper motions from existing large-area catalogs. As a pilot study of our project, we are studying OB-star candidates in the Leading Arm (LA) of the Magellanic Stream, a gaseous tidal structure with no stellar counterpart known so far. Our targets group in three clumps near regions of high HI density in the LA. If confirmed, these young stars would evidence recent star formation in the LA, and they would help better understand and constrain the formation of the LA and its interactions with the Milky Way.

  4. Velocity Space of Galactic O-B Stars

    Institute of Scientific and Technical Information of China (English)

    Zi Zhu

    2006-01-01

    Based on the Hipparcos proper motions and available radial velocity data of O-B stars, we have re-examined the local kinematical structure of the young disk population of ~ 1500 O-B stars not including the Gould-belt stars. A systematic warping motion of the stars about the direction to the Galactic center has been reconfirmed. A negative K-term implying a systematic contraction of stars in the solar vicinity has been detected. Two different distance scales are used in order to find out their impact on the kinematical parameters, and we conclude that the adopted distance scale plays an important role in characterizing the kinematical parameters at the present level of the measurement uncertainty.

  5. Photoevaporating Proplyd-like objects in Cygnus OB2

    CERN Document Server

    Wright, Nicholas J; Drew, Janet E; Guarcello, Mario G; Gutermuth, Robert A; Hora, Joseph L; Kraemer, Kathleen E

    2012-01-01

    We report the discovery of ten proplyd-like objects in the vicinity of the massive OB association Cygnus OB2. They were discovered in IPHAS H-Alpha images and are clearly resolved in broad-band HST/ACS, near-IR and Spitzer mid-IR images. All exhibit the familiar tadpole shape seen in photoevaporating objects such as the Orion proplyds, with a bright ionization front at the head facing the central cluster of massive stars, and a tail stretching in the opposite direction. Many also show secondary ionization fronts, complex tail morphologies or multiple heads. We consider the evidence that these are either proplyds or `evaporating gaseous globules' (EGGs) left over from a fragmenting molecular cloud, but find that neither scenario fully explains the observations. Typical sizes are 50,000--100,000 AU, larger than the Orion proplyds, but in agreement with the theoretical scaling of proplyd size with distance from the ionizing source. These objects are located at projected separations of 6-14pc from the OB associat...

  6. Leptin reduces the expression and increases the phosphorylation of the negative regulators of GLUT4 traffic TBC1D1 and TBC1D4 in muscle of ob/ob mice.

    Directory of Open Access Journals (Sweden)

    Neira Sáinz

    Full Text Available Leptin improves insulin sensitivity in skeletal muscle. Our goal was to determine whether proteins controlling GLUT4 traffic are altered by leptin deficiency and in vivo leptin administration in skeletal muscle of wild type and ob/ob mice. Leptin-deficient ob/ob mice were divided in three groups: control, leptin-treated (1 mg/kg/d and leptin pair-fed ob/ob mice. Microarray analysis revealed that 1,546 and 1,127 genes were regulated by leptin deficiency and leptin treatment, respectively. Among these, we identified 24 genes involved in intracellular vesicle-mediated transport in ob/ob mice. TBC1 domain family, member 1 (Tbc1d1, a negative regulator of GLUT4 translocation, was up-regulated (P = 0.001 in ob/ob mice as compared to wild types. Importantly, leptin treatment reduced the transcript levels of Tbc1d1 (P<0.001 and Tbc1d4 (P = 0.004 in the leptin-treated ob/ob as compared to pair-fed ob/ob animals. In addition, phosphorylation levels of TBC1D1 and TBC1D4 were enhanced in leptin-treated ob/ob as compared to control ob/ob (P = 0.015 and P = 0.023, respectively and pair-fed ob/ob (P = 0.036 and P = 0.034, respectively mice. Despite similar GLUT4 protein expression in wild type and ob/ob groups a different immunolocalization of this protein was evidenced in muscle sections. Leptin treatment increased GLUT4 immunoreactivity in gastrocnemius and extensor digitorum longus sections of leptin-treated ob/ob mice. Moreover, GLUT4 protein detected in immunoprecipitates from TBC1D4 was reduced by leptin replacement compared to control ob/ob (P = 0.013 and pair-fed ob/ob (P = 0.037 mice. Our findings suggest that leptin enhances the intracellular GLUT4 transport in skeletal muscle of ob/ob animals by reducing the expression and activity of the negative regulators of GLUT4 traffic TBC1D1 and TBC1D4.

  7. Leptin Reduces the Expression and Increases the Phosphorylation of the Negative Regulators of GLUT4 Traffic TBC1D1 and TBC1D4 in Muscle of ob/ob Mice

    Science.gov (United States)

    Sáinz, Neira; Rodríguez, Amaia; Catalán, Victoria; Becerril, Sara; Ramírez, Beatriz; Lancha, Andoni; Burgos-Ramos, Emma; Gómez-Ambrosi, Javier; Frühbeck, Gema

    2012-01-01

    Leptin improves insulin sensitivity in skeletal muscle. Our goal was to determine whether proteins controlling GLUT4 traffic are altered by leptin deficiency and in vivo leptin administration in skeletal muscle of wild type and ob/ob mice. Leptin-deficient ob/ob mice were divided in three groups: control, leptin-treated (1 mg/kg/d) and leptin pair-fed ob/ob mice. Microarray analysis revealed that 1,546 and 1,127 genes were regulated by leptin deficiency and leptin treatment, respectively. Among these, we identified 24 genes involved in intracellular vesicle-mediated transport in ob/ob mice. TBC1 domain family, member 1 (Tbc1d1), a negative regulator of GLUT4 translocation, was up-regulated (P = 0.001) in ob/ob mice as compared to wild types. Importantly, leptin treatment reduced the transcript levels of Tbc1d1 (P<0.001) and Tbc1d4 (P = 0.004) in the leptin-treated ob/ob as compared to pair-fed ob/ob animals. In addition, phosphorylation levels of TBC1D1 and TBC1D4 were enhanced in leptin-treated ob/ob as compared to control ob/ob (P = 0.015 and P = 0.023, respectively) and pair-fed ob/ob (P = 0.036 and P = 0.034, respectively) mice. Despite similar GLUT4 protein expression in wild type and ob/ob groups a different immunolocalization of this protein was evidenced in muscle sections. Leptin treatment increased GLUT4 immunoreactivity in gastrocnemius and extensor digitorum longus sections of leptin-treated ob/ob mice. Moreover, GLUT4 protein detected in immunoprecipitates from TBC1D4 was reduced by leptin replacement compared to control ob/ob (P = 0.013) and pair-fed ob/ob (P = 0.037) mice. Our findings suggest that leptin enhances the intracellular GLUT4 transport in skeletal muscle of ob/ob animals by reducing the expression and activity of the negative regulators of GLUT4 traffic TBC1D1 and TBC1D4. PMID:22253718

  8. Leptin reduces the expression and increases the phosphorylation of the negative regulators of GLUT4 traffic TBC1D1 and TBC1D4 in muscle of ob/ob mice.

    Science.gov (United States)

    Sáinz, Neira; Rodríguez, Amaia; Catalán, Victoria; Becerril, Sara; Ramírez, Beatriz; Lancha, Andoni; Burgos-Ramos, Emma; Gómez-Ambrosi, Javier; Frühbeck, Gema

    2012-01-01

    Leptin improves insulin sensitivity in skeletal muscle. Our goal was to determine whether proteins controlling GLUT4 traffic are altered by leptin deficiency and in vivo leptin administration in skeletal muscle of wild type and ob/ob mice. Leptin-deficient ob/ob mice were divided in three groups: control, leptin-treated (1 mg/kg/d) and leptin pair-fed ob/ob mice. Microarray analysis revealed that 1,546 and 1,127 genes were regulated by leptin deficiency and leptin treatment, respectively. Among these, we identified 24 genes involved in intracellular vesicle-mediated transport in ob/ob mice. TBC1 domain family, member 1 (Tbc1d1), a negative regulator of GLUT4 translocation, was up-regulated (P = 0.001) in ob/ob mice as compared to wild types. Importantly, leptin treatment reduced the transcript levels of Tbc1d1 (P<0.001) and Tbc1d4 (P = 0.004) in the leptin-treated ob/ob as compared to pair-fed ob/ob animals. In addition, phosphorylation levels of TBC1D1 and TBC1D4 were enhanced in leptin-treated ob/ob as compared to control ob/ob (P = 0.015 and P = 0.023, respectively) and pair-fed ob/ob (P = 0.036 and P = 0.034, respectively) mice. Despite similar GLUT4 protein expression in wild type and ob/ob groups a different immunolocalization of this protein was evidenced in muscle sections. Leptin treatment increased GLUT4 immunoreactivity in gastrocnemius and extensor digitorum longus sections of leptin-treated ob/ob mice. Moreover, GLUT4 protein detected in immunoprecipitates from TBC1D4 was reduced by leptin replacement compared to control ob/ob (P = 0.013) and pair-fed ob/ob (P = 0.037) mice. Our findings suggest that leptin enhances the intracellular GLUT4 transport in skeletal muscle of ob/ob animals by reducing the expression and activity of the negative regulators of GLUT4 traffic TBC1D1 and TBC1D4.

  9. The effect of leptin replacement on sleep-disordered breathing in the leptin-deficient ob/ob mouse.

    Science.gov (United States)

    Pho, H; Hernandez, A B; Arias, R S; Leitner, E B; Van Kooten, S; Kirkness, J P; Schneider, H; Smith, P L; Polotsky, V Y; Schwartz, A R

    2016-01-01

    Obese leptin-deficient (ob/ob) mice demonstrate defects in upper airway structural and neuromuscular control. We hypothesized that these defects predispose to upper airway obstruction during sleep, and improve with leptin administration. High-fidelity polysomnographic recordings were conducted to characterize sleep and breathing patterns in conscious, unrestrained ob/ob mice (23 wk, 67.2 ± 4.1 g, n = 13). In a parallel-arm crossover study, we compared responses to subcutaneous leptin (1 μg/h) vs. vehicle on respiratory parameters during NREM and REM sleep. Upper airway obstruction was defined by the presence of inspiratory airflow limitation (IFL), as characterized by an early inspiratory plateau in airflow at a maximum level (V̇Imax) with increasing effort. The severity of upper airway obstruction (V̇Imax) was assessed along with minute ventilation (V̇E), tidal volume (VT), respiratory rate (RR), inspiratory duty cycle, and mean inspiratory flow at each time point. IFL occurred more frequently in REM sleep (37.6 ± 0.2% vs. 1.1 ± 0.0% in NREM sleep, P leptin did not alter its frequency. V̇Imax (3.7 ± 1.1 vs. 2.7 ± 0.8 ml/s, P leptin vs. vehicle administration. The increase in V̇E was due to a significant increase in VT (0.20 ± 0.06 vs. 0.16 ± 0.05 ml, P leptin stabilized pharyngeal patency and increased drive to both the upper airway and diaphragm during sleep.

  10. An assessment of the MCNP4C weight window

    Energy Technology Data Exchange (ETDEWEB)

    Christopher N. Culbertson; John S. Hendricks

    1999-12-01

    A new, enhanced weight window generator suite has been developed for MCNP version 4C. The new generator correctly estimates importances in either a user-specified, geometry-independent, orthogonal grid or in MCNP geometric cells. The geometry-independent option alleviates the need to subdivide the MCNP cell geometry for variance reduction purposes. In addition, the new suite corrects several pathologies in the existing MCNP weight window generator. The new generator is applied in a set of five variance reduction problems. The improved generator is compared with the weight window generator applied in MCNP4B. The benefits of the new methodology are highlighted, along with a description of its limitations. The authors also provide recommendations for utilization of the weight window generator.

  11. Differential effects of pharmacological liver X receptor activation on hepatic and peripheral insulin sensitivity in lean and ob/ob mice

    NARCIS (Netherlands)

    Grefhorst, A; van Dijk, TH; Hammer, A; van der Sluijs, FH; Havinga, R; Havekes, LM; Romijn, JA; Groot, PH; Reijngoud, DJ; Kuipers, F

    2005-01-01

    Liver X receptor (LXR) agonists have been proposed to act as anti-diabetic drugs. However, pharmacological LXR activation leads to severe hepatic steatosis, a condition usually associated with insulin resistance and type 2 diabetes mellitus. To address this apparent contradiction, lean and ob/ob mic

  12. NEAR-IR Spectroscopy of Young Stars in the Braid Nebula Star Formation Region in Cygnus Ob7

    OpenAIRE

    Aspin, Colin; Beck, Tracy L.; Pyo, Tae-Soo; Davis, Chris J.; Schieven, G. M.; Khanzadyan, Tigran; Magakian, Tigran; Movsessian, Tigran; NIkogossian, Elena G.; Mitchison, Sharon; Smith, Michael D.

    2008-01-01

    We present 1.4 to 2.5 um integral field spectroscopy of 16 stars in the Braid Nebula star formation region in Cygnus OB7. These data forms one aspect of a large-scale multi-wavelength survey aimed at determining an unbiased estimate of the number, mass distribution, and evolutionary state of the young stars within this one square degree area of the previously poorly studied Lynds 1003 molecular cloud. Our new spectroscopic data, when combined with 2MASS near-IR photometry, provide evidence of...

  13. Hepatic Macrosteatosis Is Partially Converted to Microsteatosis by Melatonin Supplementation in ob/ob Mice Non-Alcoholic Fatty Liver Disease.

    Directory of Open Access Journals (Sweden)

    Alessandra Stacchiotti

    Full Text Available Obesity is a common risk factor for non-alcoholic fatty liver disease (NAFLD. Currently, there are no specific treatments against NAFLD. Thus, examining any molecule with potential benefits against this condition emerged melatonin as a molecule that influences metabolic dysfunctions. The aim of this study was to determine whether melatonin would function against NAFDL, studying morphological, ultrastuctural and metabolic markers that characterize the liver of ob/ob mice.Lean and ob/ob mice were supplemented with melatonin in the drinking water for 8 weeks. Histology and stereology were performed to assess hepatic steatosis and glycogen deposition. Ultrastructural features of mitochondria, endoplasmic reticulum (ER and their juxtapositions were evaluated in livers of all experimental groups. Furthermore, hepatic distribution and expression of markers of ER and mitochondria (calnexin, ATP sintase β, GRP78 and CHOP and metabolic dysfunction (RPB4, β-catenin and cellular longevity (SIRT1 were analyzed.Melatonin significantly reduced glycemia, identified also by a decrease of hepatic RBP4 expression, reversed macrosteatosis in microsteatosis at the hepatic pericentral zone, enlarged ER-mitochondrial distance and ameliorated the morphology and organization of these organelles in ob/ob mouse liver. Furthermore, in ob/ob mice, calnexin and ATP synthase β were partially restored, GRP78 and CHOP decreased in periportal and midzonal hepatocytes and β-catenin expression was, in part, restored in peripheral membranes of hepatocytes. Melatonin supplementation to ob/ob mice improves hepatic morphological, ultrastructural and metabolic damage that occurs as a result of NAFLD.Melatonin may be a potential adjuvant treatment to limit NAFLD and its progression into irreversible complications.

  14. OBS FOMAR POOL: Gibraltar and ALERTES-RIM experiments.

    Science.gov (United States)

    Pazos, Antonio; Martín Davila, Jose; Buforn, Elisa; Cabieces, Roberto; Santos, Jose; Sandoval, Nicolas; Roca, Antoni; Dahm, Torsten

    2016-04-01

    The Eurasian-African plate boundary crosses the called "Ibero-Maghrebian" region from the San Vicente Cape (SW Portugal) to Tunisia including the south Iberia, Alboran Sea, and northern of Morocco and Algeria. The low convergence rate at this plate boundary produces a continuous moderate seismic activity of low magnitude and shallow depth, where the occurrence of large earthquakes is separated by long time intervals, even with associated tsunamis, like the 1755 Lisbon earthquake. In this region, there are also intermediate and very deep earthquakes. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), Royal Spanish Navy Observatory (ROA) acquired three "LOSTERN" broad band (CMG-40T sensors) OBS, manufactured by KUM (Kiel, Germany), and, more recently (2014), the Complutense University of Madrid (UCM) acquired another three with Trillium 120 sensors. All of them conform the OBS FOMAR pool. Since January to November 2014, the FOMAR pool has been deployed along the Gibraltar strait (Gibraltar experiment), in collaboration with SECEGSA (Spanish society to study the fix communication through the Gibraltar Strait), to study the local microseismicity in the Gibraltar strait area. Also, since September 2015, the FOMAR pool has been deployed for 8 months in SW of the San Vicente Cape with an hexagonal array configuration as a part of ALERTES-RIM project. In this work the some preliminary results of the Gibraltar strait and ALERTES-RIM OBS experiment are shown.

  15. Determining OBS Instrument Orientations: A Comparison of Algorithms

    Science.gov (United States)

    Doran, A. K.; Laske, G.

    2015-12-01

    The alignment of the orientation of the horizontal seismometer components with the geographical coordinate system is critical for a wide variety of seismic analyses, but the traditional deployment method of ocean bottom seismometers (OBS) precludes knowledge of this parameter. Current techniques for determining the orientation predominantly rely on body and surface wave data recorded from teleseismic events with sufficiently large magnitudes. Both wave types experience lateral refraction between the source and receiver as a result of heterogeneity and anisotropy, and therefore the arrival angle of any one phase can significantly deviate from the great circle minor arc. We systematically compare the results and uncertainties obtained through current determination methods, as well as describe a new algorithm that uses body wave, surface wave, and differential pressure gauge data (where available) to invert for horizontal orientation. To start with, our method is based on the easily transportable computer code of Stachnik et al. (2012) that is publicly available through IRIS. A major addition is that we utilize updated global dispersion maps to account for lateral refraction, as was done by Laske (1995). We also make measurements in a wide range of frequencies, and analyze surface wave trains of repeat orbits. Our method has the advantage of requiring fewer total events to achieve high precision estimates, which is beneficial for OBS deployments that can be as short as weeks. Although the program is designed for the purpose of use with OBS instruments, it also works with standard land installations. We intend to provide the community with a program that is easy to use, requires minimal user input, and is optimized to work with data cataloged at the IRIS DMC.

  16. Effects of the switching time in OPS/OBS networks

    Institute of Scientific and Technical Information of China (English)

    Harald (φ)verby; Norvald Stol

    2004-01-01

    In this paper we present an analytical model, which considers the effects of the switching time on the network performance in service differentiated optical packet/burst switching (OPS/OBS) networks. Our results indicate that the switching time must be less than 10 % of the packet/burst duration in order to avoid any significant reductions in the network performance. Furthermore, regarding a network with full wavelength conversion, we show that the benefits of statistical resource sharing are almost non-existent for low priority traffic when the switching time is large.

  17. The Seismic Broad Band Western Mediterranean (wm) Network and the Obs Fomar Pool: Current state and Obs activities.

    Science.gov (United States)

    Pazos, Antonio; Davila, Jose Martin; Buforn, Elisa; Bezzeghoud, Mourad; Harnafi, Mimoun; Mattesini, Mauricio; Caldeira, Bento; Hanka, Winfried; El Moudnib, Lahcen; Strollo, Angelo; Roca, Antoni; Lopez de Mesa, Mireya; Dahm, Torsten; Cabieces, Roberto

    2016-04-01

    The Western Mediterranean (WM) seismic network started in 1996 as an initiative of the Royal Spanish Navy Observatory (ROA) and the Universidad Complutense de Madrid (UCM), with the collaboration of the GeoForschungsZentrum (GFZ) of Potsdam. A first broad band seismic station (SFUC) was installed close to Cádiz (South Spain). Since then, additional stations have been installed in the Ibero-Moghrebian region. In 2005, the "WM" code was assigned by the FDSN and new partners were jointed: Evora University (UEVO, Portugal), the Scientifique Institute of Rabat (ISRABAT, Morocco), and GFZ. Now days, the WM network is composed by 15 BB stations, all of them with Streckaisen STS-2 or STS-2.5 sensors, Quanterra or Earthdata digitizers and SeiscomP. Most them have co-installed a permanent geodetic GPS stations, and some them also have an accelerometer. There are 10 stations deployed in Spanish territory (5 in the Iberian peninsula, 1 in Balearic islands and 4 in North Africa Spanish places) with VSAT or Internet communications, 2 in Portugal (one of them without real time), and 3 in Morocco (2 VSAT and 1 ADSL). Additionally, 2 more stations (one in South Spain and one in Morocco) will be installed along this year. Additionally ROA has deployed a permanent real time VBB (CMG-3T: 360s) station at the Alboran Island. Due to the fact that part of the seismic activity is located at marine areas, and also because of the poor geographic azimuthal coverage at some zones provided by the land stations (specially in the SW of the San Vicente Cape area), ROA and UCM have acquired six broad band "LOBSTERN" OBS, manufactured by KUM (Kiel, Germany), conforming the OBS FOMAR pool. Three of them with CMG-40T sensor and the other with Trillium 120. These OBS were deployed along the Gibraltar strait since January to November 2014 to study the microseismicity in the Gibraltar strait area. In September 2015 FOMAR network has been deployed in SW of the San Vicente Cape for 8 months as a part of

  18. On the observability of bow shocks of Galactic runaway OB stars

    Science.gov (United States)

    Meyer, D. M.-A.; van Marle, A.-J.; Kuiper, R.; Kley, W.

    2016-06-01

    Massive stars that have been ejected from their parent cluster and supersonically sailing away through the interstellar medium (ISM) are classified as exiled. They generate circumstellar bow-shock nebulae that can be observed. We present two-dimensional, axisymmetric hydrodynamical simulations of a representative sample of stellar wind bow shocks from Galactic OB stars in an ambient medium of densities ranging from nISM = 0.01 up to 10.0 cm- 3. Independently of their location in the Galaxy, we confirm that the infrared is the most appropriated waveband to search for bow shocks from massive stars. Their spectral energy distribution is the convenient tool to analyse them since their emission does not depend on the temporary effects which could affect unstable, thin-shelled bow shocks. Our numerical models of Galactic bow shocks generated by high-mass ( ≈ 40 M⊙) runaway stars yield H α fluxes which could be observed by facilities such as the SuperCOSMOS H-Alpha Survey. The brightest bow-shock nebulae are produced in the denser regions of the ISM. We predict that bow shocks in the field observed at H α by means of Rayleigh-sensitive facilities are formed around stars of initial mass larger than about 20 M⊙. Our models of bow shocks from OB stars have the emission maximum in the wavelength range 3 ≤ λ ≤ 50 μm which can be up to several orders of magnitude brighter than the runaway stars themselves, particularly for stars of initial mass larger than 20 M⊙.

  19. Ccontrolling the Transition Between "Higher" and "Lower" State of OB in Coherent Atomic Mediumntrolling the Transition Between "Higher" and "Lower" State of OB in Coherent Atomic Medium

    Institute of Scientific and Technical Information of China (English)

    WANG Hai; CHANG Hong; WU Haibin; XIE Chande

    2004-01-01

    @@ We present a new experimental demonstration that the threshold points and shape of OB hysteresis curve in a four-level Rb atomic system inside an optical cavity were controllably changed by optical signals.Tuning the triggering optical signal to two different transitions of the atomic system we found that the OB threshold points shift toward different direction and at the same time the shape of the OB curve is also changed.For a given intensity of probe laser the OB system can be reliably inversed from its lower stable state to upper state under the triggering of a suitably tuned optical pulse signal (we named it up-controlling signal).More interesting, the inversed OB state does not drop to its initial lower stable state after the triggering pulse signal has passed, but moves to the upper branch of the initial OB curve and stably stays there until another optical signal tuned on other atomic transition (named down-controlling signal) coming.The result shows that there is the ability of information storage in the OB system.The experiments are reasonably explained with the change of cavity resonant condition resulting from the enhanced third-order nonlinearity in multilevel atomic system owing to atomic coherence.

  20. Reduction of obesity, as induced by leptin, reverses endothelial dysfunction in obese (Lep(ob)) mice

    Science.gov (United States)

    Winters, B.; Mo, Z.; Brooks-Asplund, E.; Kim, S.; Shoukas, A.; Li, D.; Nyhan, D.; Berkowitz, D. E.

    2000-01-01

    Obesity is a major health care problem and is associated with significant cardiovascular morbidity. Leptin, a neuroendocrine hormone released by adipose tissue, is important in modulating obesity by signaling satiety and increasing metabolism. Moreover, leptin receptors are expressed on vascular endothelial cells (ECs) and mediate angiogenesis. We hypothesized that leptin may also play an important role in vasoregulation. We investigated vasoregulatory mechanisms in the leptin-deficient obese (ob/ob) mouse model and determined the influence of leptin replacement on endothelial-dependent vasorelaxant responses. The direct effect of leptin on EC nitric oxide (NO) production was also tested by using 4, 5-diaminofluorescein-2 diacetate staining and measurement of nitrate and nitrite concentrations. Vasoconstrictor responses to phenylephrine, norepinephrine, and U-46619 were markedly enhanced in aortic rings from ob/ob mice and were modulated by NO synthase inhibition. Vasorelaxant responses to ACh were markedly attenuated in mesenteric microvessels from ob/ob mice. Leptin replacement resulted in significant weight loss and reversal of the impaired endothelial-dependent vasorelaxant responses observed in ob/ob mice. Preincubation of ECs with leptin enhanced the release of NO production. Thus leptin-deficient ob/ob mice demonstrate marked abnormalities in vasoregulation, including impaired endothelial-dependent vasodilation, which is reversed by leptin replacement. These findings may be partially explained by the direct effect of leptin on endothelial NO production. These vascular abnormalities are similar to those observed in obese, diabetic, leptin-resistant humans. The ob/ob mouse may, therefore, be an excellent new model for the study of the cardiovascular effects of obesity.

  1. Expression pattern of leptin and leptin receptor (OB-R) in human gastric cancer

    Institute of Scientific and Technical Information of China (English)

    Makoto Ishikawa; Joji Kitayama; Hirokazu Nagawa

    2006-01-01

    AIM: To examine the expression of leptin and its receptor, OB-R, in normal gastric mucosa and neoplasia.METHODS: By immunohistochemical staining using specific antibodies, we evaluated the expression of leptin and OB-R in 207 gastric carcinomas (100 early and 107 advanced carcinomas) and analyzed their relationship with clinicopathological features.RESULTS: Both normal gastric epithelium and carcinoma cells expressed a significant level of leptin. In cases with OB-R staining, carcinoma cells showed OB-Rpositive expression, but the intensity was weaker than that in normal mucosa. The expression of OB-R showed a significant correlation with the level of leptin expression. The expression levels of both leptin and OB-R tend ed to increase as the depth of tumor invasion or TMN stage increased (P < 0.01). Lymph node metastasis was detected in 49.5% (47/95) of leptin-strong cases and in 50.5% (48/95) of OB-R-positive cases, and the rate was 33% (37/112) in leptin-weak cases and 17% (19/112) in OB-R-negative cases. Both venous and lymphatic invasion also tended to be observed frequently in positive tumors as compared with negative tumors. Interestingly,in the 96 leptin- or OB-R-positive tumors, hematogenous metastasis was detected preoperatively in 3 (3.1%) patients. In contrast, none of the carcinomas that lacked expression of leptin and OB-R showed hematogenous metastasis.CONCLUSION: Overexpression of leptin and expression of OB-R may play a positive role in the process of progression in gastric cancer. Functional upregulation of leptin/OB-R may have a positive role in the development and initial phase of progression in gastric cancer.

  2. Study of Eclipsing Binary and Multiple Systems in OB Associations IV: Cas OB6 Member DN Cas

    CERN Document Server

    Bakis, V; Bilir, S; Eker, Z

    2016-01-01

    An early-type, massive, short-period ($P_{\\rm orb}=2^{\\rm d}.310951$) eclipsing spectroscopic binary DN Cas has been re-visited with new spectral and photometric data. The masses and radii of the components have been obtained as $M_1=19.04\\pm0.07 M_\\odot$, $M_2=13.73\\pm 0.05M_\\odot$ and $R_1=7.22\\pm0.06 R_\\odot$, $R_2=5.79\\pm0.06R_\\odot$, respectively. Both components present synchronous rotation ($V_{\\rm rot1}=160\\,$km s$^{-1}$, $V_{\\rm rot2}=130\\,$km s$^{-1}$) with their orbit. Orbital period analysis yielded a physically bound additional component in the system with a minimum mass of $M_3=0.88 M_\\odot$ orbiting in an eccentric orbit ($e=0.37\\pm0.2$) with an orbital period of $P_{12}=42\\pm9$ yrs. High precision absolute parameters of the system allowed us to derive a distance to DN Cas as 1.7$\\pm$0.2 kpc which locates the system within the borders of the Cas OB6 association (d=1.8 kpc; Mel'nik & Dambis, 2009). The space velocities and the age of DN Cas are in agreement with those of Cas OB6. The age of ...

  3. X-ray properties and interface study of B4C/Mo and B4C/Mo2C periodic multilayers

    Science.gov (United States)

    Choueikani, F.; Bridou, F.; Lagarde, B.; Meltchakov, E.; Polack, F.; Mercere, P.; Delmotte, F.

    2013-04-01

    We present a comparative study of B4C/Mo and B4C/Mo2C periodic multilayer structures deposited by magnetron sputtering. The characterization was performed by grazing incidence X-ray reflectometry at two different energies and high resolution transmission electron microscopy. The experimental results indicate the existence of an interdiffusion layer at the B4C-on-Mo interface in the B4C/Mo system. Thus, the B4C/Mo multilayers were modeled by an asymmetric structure with three layers in each period. The thickness of B4C-on-Mo interfacial layer was estimated about 1.1 nm. The B4C/Mo2C multilayers present less interdiffusion and are well modeled by a symmetric structure without interfacial layers. This study shows that B4C/Mo2C structure is an interesting alternative to B4C/Mo multilayer for X-ray optic applications.

  4. The Ob Estuary (Kara Sea) Coastal Dynamics Interannual Variability Assessment

    Science.gov (United States)

    Kopa-Ovdienko, N.; Volobueva, N.; Ogorodov, S.

    2012-04-01

    There are several promising gas fields in the Ob Estuary. For their development comprehensive research, including coastal dynamics assessment, is required. To estimate current and speak about future coastal dynamics rates we need to investigate its interannual variability connecting it with variability of major coastal dynamics factors. It is known that in this region one of the main coastal dynamics factors is wave action, which, in turn, depends on wind velocity and direction. Wind data for ice-free period were derived from nearby hydro-meteorological stations. The research was conducted for two sections of the Ob Estuary coast. One section is located on the eastern coast of the estuary (Taz peninsula); the other is located on the western one (Yamal peninsula). Each of these sections is 10 km length. For key-sites of the coast wave-dangerous rhumbs were determined. For ice-free period of each year accumulated summer storm duration (ASSD) - number of hours with strong winds (≥10 m/s) from wave-dangerous directions - was calculated for both sections of coast. Supposing that coast retreat rate is proportional to number of hours with strong winds from wave-dangerous rhumbs, we can approximately assess interannual variability of coast retreat rate. Our research revealed that: 1)There are significant (from hours to a few hundreds of hours) differences in ASSD from year to year due to short ice-free period and high variability of wind velocity and direction. So, we can expect sharp interannual differences in coastal retreat rate. 2)The duration of strong winds from wave-dangerous rhumbs during ice-free period is more on the eastern coast of the estuary than on the western. This goes from the predominance of northern and northwestern winds during ice-free period. These winds cause waves leading to coastal erosion on the eastern coast of estuary and don't cause such waves on the western one. However, we can't draw conclusions about the comparative rates of coastal

  5. New Low-Mass Wide Companions to Members of the Sco-Cen OB Association

    Science.gov (United States)

    Finn, Molly; Mamajek, Eric E.; Luhman, Kevin; Murphy, Simon

    2017-01-01

    We have conducted a survey for wide common proper motion companions to 512 members of the Upper Cen-Lup (UCL) and Lower Cen-Cru (LCC) subgroups of the Sco-Cen OB association using astrometry and photometry from the SPM4 catalog. Companion candidates were selected within 3 arcminutes (23 kau = 0.11 pc at d = 130 pc). We find that 12% of the Sco-Cen members have stellar companions in the separation range 3-20 kau. Optical spectra of 16 candidate companions were taken with the new COSMOS spectrograph on the Blanco 4-m telescope and the Wide Field Spectrograph on the Australian National University 2.3-m telescope. The spectroscopic survey yielded 14 M-type stars with Na I surface gravity index indicative of pre-MS status, of which half were Li-rich (along with two background giant interlopers). Seven stars in the range M1-M4.5 appear to be Li depleted, but otherwise seem to be pre-MS due to their chromospheric activity, low surface gravity via the Na I index, and their co- movement with other young stars in Sco-Cen. We suggest that these stars represent the Li depletion boundary for UCL and LCC. We acknowledge support from NSF award AST-1313029 and the REU Site in Physics and Astrophysics at the University of Rochester supported by NSF award PHY-1156339.

  6. 3D MHD simulations of subsurface convection in OB stars

    CERN Document Server

    Cantiello, Matteo; Brandenburg, Axel; Del Sordo, Fabio; Käpylä, Petri; Langer, Norbert

    2010-01-01

    During their main sequence evolution, massive stars can develop convective regions very close to their surface. These regions are caused by an opacity peak associated with iron ionization. Cantiello et al. (2009) found a possible connection between the presence of sub-photospheric convective motions and small scale stochastic velocities in the photosphere of early-type stars. This supports a physical mechanism where microturbulence is caused by waves that are triggered by subsurface convection zones. They further suggest that clumping in the inner parts of the winds of OB stars could be related to subsurface convection, and that the convective layers may also be responsible for stochastic excitation of non-radial pulsations. Furthermore, magnetic fields produced in the iron convection zone could appear at the surface of such massive stars. Therefore subsurface convection could be responsible for the occurrence of observable phenomena such as line profile variability and discrete absorption components. These p...

  7. Dropping Probability Reduction in OBS Networks: A Simple Approach

    KAUST Repository

    Elrasad, Amr

    2016-08-01

    In this paper, we propose and derive a slotted-time model for analyzing the burst blocking probability in Optical Burst Switched (OBS) networks. We evaluated the immediate and delayed signaling reservation schemes. The proposed model compares the performance of both just-in-time (JIT) and just-enough-time (JET) signaling protocols associated with of void/non-void filling link scheduling schemes. It also considers none and limited range wavelength conversions scenarios. Our model is distinguished by being adaptable to different offset-time and burst length distributions. We observed that applying a limited range of wavelength conversion, burst blocking probability is reduced by several orders of magnitudes and yields a better burst delivery ratio compared with full wavelength conversion.

  8. 9 cenas, algumas obs-cenas, da rua

    Directory of Open Access Journals (Sweden)

    Robert Moses Pechman

    2009-08-01

    Full Text Available Importa aqui tomar o acontecimento urbano como sintoma da cidade. Mas de que sofre a cidade? De excesso de individualismo e do escasseamento da vida pública na rua. Mas se o que caracteriza a cidade é o acolhimento do Outro, que se desdobra em convivialidades e em sociabilidades, como podemos pensar numa cidade sem que a questão da hospitalidade venha à tona? À propósito dessa contradição entre cidade e individualismo e privativismo e hospitalidade, me ponho a observar nossas ruas e a divisar certas cenas urbanas, depreendendo daí o que essas cenas podem nos contar de um ethos citadino. E, sim, elas nos contam muitas coisas de uma nova paisagem urbana/humana que insiste em desmanchar a imagem do acolhimento como a cena primordial da cidade, impondo sua obscena verdade, sua cena obs-cena.

  9. Performance analysis of signaling protocols on OBS switches

    Science.gov (United States)

    Kirci, Pinar; Zaim, A. Halim

    2005-10-01

    In this paper, Just-In-Time (JIT), Just-Enough-Time (JET) and Horizon signalling schemes for Optical Burst Switched Networks (OBS) are presented. These signaling schemes run over a core dWDM network and a network architecture based on Optical Burst Switches (OBS) is proposed to support IP, ATM and Burst traffic. In IP and ATM traffic several packets are assembled in a single packet called burst and the burst contention is handled by burst dropping. The burst length distribution in IP traffic is arbitrary between 0 and 1, and is fixed in ATM traffic at 0,5. Burst traffic on the other hand is arbitrary between 1 and 5. The Setup and Setup ack length distributions are arbitrary. We apply the Poisson model with rate λ and Self-Similar model with pareto distribution rate α to identify inter-arrival times in these protocols. We consider a communication between a source client node and a destination client node over an ingress and one or more multiple intermediate switches.We use buffering only in the ingress node. The communication is based on single burst connections in which, the connection is set up just before sending a burst and then closed as soon as the burst is sent. Our analysis accounts for several important parameters, including the burst setup, burst setup ack, keepalive messages and the optical switching protocol. We compare the performance of the three signalling schemes on the network under as burst dropping probability under a range of network scenarios.

  10. Augmenting the Stability of OB Dump by Using Fly Ash: A Geo Technical Approach to Sustainably Manage OB Dump at Jharia Coal Field, India

    Directory of Open Access Journals (Sweden)

    Anup Kumar Gupta*

    2016-04-01

    Full Text Available This paper is mainly focused over the possible utilization of fly ash along with OB dump to enhance the stability of OB dump and thus provide a sustainable approach for better waste management of both these materials simultaneously. Instability of coal mine overburden (OB dumps is an important problem in most of the coal mines like Jharia coalfields in India. This is mainly occurring due to sliding nature of the rock material, lack of vegetation etc. Numbers of Environmental and health issues are associated with these unstable OB dumps. As it may easily flow with running water can contaminate the nearby water resource as well as carbonaceous content of the dump causes air pollution due to simultaneous combustion. On the other hand management of coal ash that is produced from thermal plants is also an important task. Dumping of fly ash in open may cause number of environmental problems. Various geotechnical and physical parameters such as particle size analysis, specific gravity, density, and friction angle/cohesion test have been performed to check the stability of OB dump and to analyze impacts of fly ash utilization to stabilize the OB dump.

  11. Leptin Administration Favors Muscle Mass Accretion by Decreasing FoxO3a and Increasing PGC-1α in ob/ob Mice

    Science.gov (United States)

    Sáinz, Neira; Rodríguez, Amaia; Catalán, Victoria; Becerril, Sara; Ramírez, Beatriz; Gómez-Ambrosi, Javier; Frühbeck, Gema

    2009-01-01

    Absence of leptin has been associated with reduced skeletal muscle mass in leptin-deficient ob/ob mice. The aim of our study was to examine the effect of leptin on the catabolic and anabolic pathways regulating muscle mass. Gastrocnemius, extensor digitorum longus and soleus muscle mass as well as fiber size were significantly lower in ob/ob mice compared to wild type littermates, being significantly increased by leptin administration (P<0.001). This effect was associated with an inactivation of the muscle atrophy-related transcription factor forkhead box class O3 (FoxO3a) (P<0.05), and with a decrease in the protein expression levels of the E3 ubiquitin-ligases muscle atrophy F-box (MAFbx) (P<0.05) and muscle RING finger 1 (MuRF1) (P<0.05). Moreover, leptin increased (P<0.01) protein expression levels of peroxisome proliferator-activated receptor γ coactivator-1α (PGC-1α), a regulator of muscle fiber type, and decreased (P<0.05) myostatin protein, a negative regulator of muscle growth. Leptin administration also activated (P<0.01) the regulators of cell cycle progression proliferating cell nuclear antigen (PCNA) and cyclin D1, and increased (P<0.01) myofibrillar protein troponin T. The present study provides evidence that leptin treatment may increase muscle mass of ob/ob mice by inhibiting myofibrillar protein degradation as well as enhancing muscle cell proliferation. PMID:19730740

  12. Leptin administration restores the altered adipose and hepatic expression of aquaglyceroporins improving the non-alcoholic fatty liver of ob/ob mice.

    Science.gov (United States)

    Rodríguez, Amaia; Moreno, Natalia R; Balaguer, Inmaculada; Méndez-Giménez, Leire; Becerril, Sara; Catalán, Victoria; Gómez-Ambrosi, Javier; Portincasa, Piero; Calamita, Giuseppe; Soveral, Graça; Malagón, María M; Frühbeck, Gema

    2015-07-10

    Glycerol is an important metabolite for the control of lipid accumulation in white adipose tissue (WAT) and liver. We aimed to investigate whether exogenous administration of leptin improves features of non-alcoholic fatty liver disease (NAFLD) in leptin-deficient ob/ob mice via the regulation of AQP3 and AQP7 (glycerol channels mediating glycerol efflux in adipocytes) and AQP9 (aquaglyceroporin facilitating glycerol influx in hepatocytes). Twelve-week-old male wild type and ob/ob mice were divided in three groups as follows: control, leptin-treated (1 mg/kg/d) and pair-fed. Leptin deficiency was associated with obesity and NAFLD exhibiting an AQP3 and AQP7 increase in WAT, without changes in hepatic AQP9. Adipose Aqp3 and hepatic Aqp9 transcripts positively correlated with markers of adiposity and hepatic steatosis. Chronic leptin administration (4-weeks) was associated with improved body weight, whole-body adiposity, and hepatosteatosis of ob/ob mice and to a down-regulation of AQP3, AQP7 in WAT and an up-regulation of hepatic AQP9. Acute leptin stimulation in vitro (4-h) induced the mobilization of aquaglyceroporins towards lipid droplets (AQP3) and the plasma membrane (AQP7) in murine adipocytes. Our results show that leptin restores the coordinated regulation of fat-specific AQP7 and liver-specific AQP9, a step which might prevent lipid overaccumulation in WAT and liver in obesity.

  13. Leptin administration favors muscle mass accretion by decreasing FoxO3a and increasing PGC-1alpha in ob/ob mice.

    Directory of Open Access Journals (Sweden)

    Neira Sáinz

    Full Text Available Absence of leptin has been associated with reduced skeletal muscle mass in leptin-deficient ob/ob mice. The aim of our study was to examine the effect of leptin on the catabolic and anabolic pathways regulating muscle mass. Gastrocnemius, extensor digitorum longus and soleus muscle mass as well as fiber size were significantly lower in ob/ob mice compared to wild type littermates, being significantly increased by leptin administration (P<0.001. This effect was associated with an inactivation of the muscle atrophy-related transcription factor forkhead box class O3 (FoxO3a (P<0.05, and with a decrease in the protein expression levels of the E3 ubiquitin-ligases muscle atrophy F-box (MAFbx (P<0.05 and muscle RING finger 1 (MuRF1 (P<0.05. Moreover, leptin increased (P<0.01 protein expression levels of peroxisome proliferator-activated receptor gamma coactivator-1alpha (PGC-1alpha, a regulator of muscle fiber type, and decreased (P<0.05 myostatin protein, a negative regulator of muscle growth. Leptin administration also activated (P<0.01 the regulators of cell cycle progression proliferating cell nuclear antigen (PCNA and cyclin D1, and increased (P<0.01 myofibrillar protein troponin T. The present study provides evidence that leptin treatment may increase muscle mass of ob/ob mice by inhibiting myofibrillar protein degradation as well as enhancing muscle cell proliferation.

  14. A specific assay for quantification of human C4c by use of an anti-C4c monoclonal antibody

    DEFF Research Database (Denmark)

    Pilely, Katrine; Skjoedt, Mikkel-Ole; Nielsen, Christian;

    2014-01-01

    and samples from factor I deficient patients. The specificity of the mAb was further evaluated by immunoprecipitation techniques and by analysis of eluted fragments of C4 after immunoaffinity chromatography. The anti-C4c mAb was confirmed to be C4c specific, as it showed no cross-reactivity with native (un...

  15. Technical Memorandum: A Training Evaluation Framework for PSTC MilObs Course

    Science.gov (United States)

    2009-09-01

    une situation de violation des droits de la personne. Dans ce scénario, les stagiaires non armés rencontrent des policiers armés (un sergent et un...Manage a MilObs team • Ability to organize team site • Ability to operate communications equipment • Managing diversity Direct a MilObs team

  16. Transcriptional activation of the mouse obese (ob) gene by CCAAT/enhancer binding protein alpha

    DEFF Research Database (Denmark)

    Hwang, C S; Mandrup, S; MacDougald, O A

    1996-01-01

    Like other adipocyte genes that are transcriptionally activated by CCAAT/enhancer binding protein alpha (C/EBP alpha) during preadipocyte differentiation, expression of the mouse obese (ob) gene is immediately preceded by the expression of C/EBP alpha. While the 5' flanking region of the mouse ob...

  17. Data of evolutionary structure change: 1MRVA-1OB3A [Confc[Archive

    Lifescience Database Archive (English)

    Full Text Available 1MRVA-1OB3A 1MRV 1OB3 A A VTMNDFDYLKLLGKGTFGKVILVREKATGRYYAMKILR-...ndex> 1MRV A 1MRVA H...entryChain> 1MRV A 1MRVA PEVLE-DN...entryChain> 1MRV A 1MRVA VREKATGR...bID> A 1MRVA ANGGELFFHLS

  18. Performance and cost analysis of all-optical switching: OBS and OCS

    Directory of Open Access Journals (Sweden)

    Ekularn Dhavarudha

    2011-08-01

    Full Text Available This paper presents a study of performance and cost analysis of optical circuit switching (OCS and optical burstswitching (OBS by proposing the clear images of their node architectures and cost formulations. Then, we apply servicelevel agreement (SLA of the high quality of service application in the terms of network blocking probability and averagenetwork delay to demonstrate OCS and OBS performances, their investment costs, and network dimensioning methodology.Applying SLA to our studies can illustrate the impact of contention resolution and blocking resolution schemes to theperformances and costs of OBS and OCS, accordingly. The simulations illustrate that OBS applying WC gives the bestperformance among all architectures deploying the same offered bandwidth. The investigations also show that WC is a majortechnique contributing high performance gain to both OCS and OBS. Especially for OBS, WC is an important scheme allowingOBS high data grooming property as its performance gain contributing to OBS is much higher than those of OCS. For thecost analysis, OCS is the most economic among all architectures. BA provides the most cost effectiveness among all OBScontention resolution schemes. Lastly, FDL is the least cost effective scheme as it gives little performance enhancement butadds more cost to the network.

  19. MW-OBS: An Improved Pruning Method for Topology Design of Neural Networks

    Institute of Scientific and Technical Information of China (English)

    ZHU Yan; LU Yingrong; LI Qian

    2006-01-01

    Topology design of artificial neural networks (ANNs) is an important problem for large scale applications. This paper describes a new efficient pruning method, the multi-weight optimal brain surgeon (MW-OBS) method, to optimize neural network topologies. The advantages and disadvantages of the OBS and unit-OBS were analyzed to develop the method. Actually, optimized topologies are difficult to get within reasonable times for complex problems. Motivating by the mechanism of natural neurons, the MW-OBS method balances the accuracy and the time complexity to achieve better neural network performance. The method will delete multiple connections among neurons according to the second derivative of the error function, so the arithmetic converges rapidly while the accuracy of the neural network remains high. The stability and generalization ability of the method are illustrated in a Java program. The results show that the MW-OBS method has the same accuracy as OBS, but time is similar to that of unit-OBS. Therefore, the MW-OBS method can be used to efficiently optimize structures of neural networks for large scale applications.

  20. Irradiated Interfaces in the Ara OB1, Carina, Eagle Nebula, and Cyg OB2 Massive Star Formation Regions

    CERN Document Server

    Hartigan, P; Cleeves, L I

    2013-01-01

    Regions of massive star formation offer some of the best and most easily-observed examples of radiation hydrodynamics. Boundaries where fully-ionized H II regions transition to neutral/molecular photodissociation regions (PDRs) are of particular interest because marked temperature and density contrasts across the boundaries lead to evaporative flows and fluid dynamical instabilities that can evolve into spectacular pillar-like structures. When detached from their parent clouds, pillars become ionized globules that often harbor one or more young stars. H2 molecules at the interface between a PDR and an H II region absorb ultraviolet light from massive stars, and the resulting fluoresced infrared emission lines are an ideal way to trace this boundary independent of obscuring dust. This paper presents H2 images of four regions of massive star formation that illustrate different types of PDR boundaries. The Ara OB1 star formation region contains a striking long wall that has several wavy structures which are pres...

  1. Analysis of the kinematic structure in the Cygnus OB1 association

    Science.gov (United States)

    Costado, M. T.; Alfaro, E. J.; González, M.; Sampedro, L.

    2017-03-01

    The Cygnus OB1 association is part of a larger star-forming complex located in the direction of Cygnus, but whose main sub-systems may be distributed at different distances from the sun. We have collected radial velocity (RV) data for more than 300 stars in an area of 5 x 5 squared degrees centered in the Cygnus OB1 association from the literature. This area also covers part of the Cygnus OB3 and OB9 associations, because of the diffuse limits between them. In this poster, we present the results of a clustering analysis in the subspace of the phase space formed by angular coordinates and RV in the field of the Cygnus OB1 association using the current available data. Three main groups have been detected corresponding to different RV and distances.

  2. File list: Oth.ALL.50.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.50.Kdm4c.AllCell mm9 TFs and others Kdm4c All cell types SRX424019,SRX42401...8,SRX424007,SRX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.ALL.50.Kdm4c.AllCell.bed ...

  3. File list: Oth.ALL.05.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.05.Kdm4c.AllCell mm9 TFs and others Kdm4c All cell types SRX424019,SRX42401...8,SRX424007,SRX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.ALL.05.Kdm4c.AllCell.bed ...

  4. File list: Oth.ALL.10.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.ALL.10.Kdm4c.AllCell mm9 TFs and others Kdm4c All cell types SRX424018,SRX42401...9,SRX424007,SRX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.ALL.10.Kdm4c.AllCell.bed ...

  5. File list: Oth.PSC.50.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.50.Kdm4c.AllCell mm9 TFs and others Kdm4c Pluripotent stem cell SRX424007,S...RX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.50.Kdm4c.AllCell.bed ...

  6. File list: Oth.PSC.20.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.20.Kdm4c.AllCell mm9 TFs and others Kdm4c Pluripotent stem cell SRX424007,S...RX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.20.Kdm4c.AllCell.bed ...

  7. File list: Oth.PSC.05.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.05.Kdm4c.AllCell mm9 TFs and others Kdm4c Pluripotent stem cell SRX424007,S...RX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.05.Kdm4c.AllCell.bed ...

  8. File list: Oth.PSC.10.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.PSC.10.Kdm4c.AllCell mm9 TFs and others Kdm4c Pluripotent stem cell SRX424007,S...RX424008 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.PSC.10.Kdm4c.AllCell.bed ...

  9. File list: Oth.ALL.20.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

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  10. Selective activation of FGFR4 by an FGF19 variant does not improve glucose metabolism in ob/ob mice.

    Science.gov (United States)

    Wu, Xinle; Ge, Hongfei; Lemon, Bryan; Weiszmann, Jennifer; Gupte, Jamila; Hawkins, Nessa; Li, Xiaofan; Tang, Jie; Lindberg, Richard; Li, Yang

    2009-08-25

    FGF19 is a hormone that regulates bile acid and glucose homeostasis. Progress has been made in identifying cofactors for receptor activation. However, several functions of FGF19 have not yet been fully defined, including the actions of FGF19 on target tissues, its FGF receptor specificity, and the contributions of other cofactors, such as heparin. Here, we explore the requirements for FGF19-FGFR/co-receptor interactions and signaling in detail. We show that betaKlotho was essential for FGF19 interaction with FGFRs 1c, 2c, and 3c, but FGF19 was able to interact directly with FGFR4 in the absence of betaKlotho in a heparin-dependent manner. Further, FGF19 activated FGFR4 signaling in the presence or absence of betaKlotho, but activation of FGFRs 1c, 2c, or 3c was completely betaKlotho dependent. We then generated an FGF19 molecule, FGF19dCTD, which has a deletion of the C-terminal region responsible for betaKlotho interaction. We determined that betaKlotho-dependent FGFR1c, 2c, and 3c interactions and activation were abolished, and betaKlotho-independent FGFR4 activation was preserved; therefore, FGF19dCTD is an FGFR4-specific activator. This unique FGF19 molecule specifically activated FGFR4-dependent signaling in liver and suppressed CYP7A1 expression in vivo, but was unable to activate signaling in adipose where FGFR4 expression is very low. Interestingly, unlike FGF19, treatment of ob/ob mice with FGF19dCTD failed to improve glucose levels and insulin sensitivity. These results suggest that FGF19-regulated liver bile acid metabolism could be independent of its glucose-lowering effect, and direct FGFR activation in adipose tissue may play an important role in the regulation of glucose homeostasis.

  11. LiFePO4/C nanocomposites for lithium-ion batteries

    Science.gov (United States)

    Eftekhari, Ali

    2017-03-01

    LiFePO4, as the most famous member of the family of olivine-type lithium transition metal phosphates, is one of the promising candidates for the cathodes of lithium-ion batteries. However, its battery performance is limited by its low electrical conductivity and slow Li solid-state diffusion. Various methods have been attempted to improve the battery performance of lithium iron phosphate. Among them, compositing the LiFePO4 with carbon nanomaterials seems to be the most promising, as it is facile and efficient. Carbon nanomaterials usually serve as a conductive agent to improve the electrical conductivity while increasing the material porosity in which the solid-state diffusion distances are significantly shortened. Owing to the popularity of various carbonaceous nanomaterials, there is no straightforward line of research for comparing the LiFePO4/C nanocomposites. This review aims to provide a general perspective based on the research achievements reported in the literature. While surveying the research findings reported in the literature, controversial issues are also discussed. The possible contribution of pseudocapacitance as a result of functionalized carbon or LiFePO4 lattice defects is described, since from a practical perspective, a LiFePO4/C electrode can be considered as a supercapacitor at high C rates (with a specific capacitance as large as 200 F g-1). The Li diffusion in LiFePO4 has not been well understood yet; while the Li diffusion within the LiFePO4 lattice seems to be quite fast, the peculiar interfacial electrochemistry of LiFePO4 slows down the diffusion within the entire electrode by a few orders of magnitude.

  12. Insulin resistance, steatohepatitis, and hepatocellular carcinoma in a new congenic strain of Fatty Liver Shionogi (FLS) mice with the Lep(ob) gene.

    Science.gov (United States)

    Soga, Masahiko; Hashimoto, Setsuko; Kishimoto, Yoshio; Hirasawa, Tsutomu; Makino, Susumu; Inagaki, Shuichiro

    2010-01-01

    In order to examine the influence of obesity on metabolic disorder and liver pathogenesis of the Fatty Liver Shionogi (FLS) mouse, which develops hereditary fatty liver and spontaneous liver tumors, we established a new congenic strain named FLS-Lep(ob). The Lep(ob) gene of the C57BL/6JWakShi (B6)-Lep(ob)/Lep(ob) mouse was transferred into the genome of the FLS mouse, by backcross mating. FLS-Lep(ob)/Lep(ob) mice were maintained by intercrossing between Lep(ob)-heterozygous littermates. The FLS-Lep(ob)/Lep(ob) mice of both sexes developed remarkable hyperphagia, obesity and type 2 diabetes mellitus. At 12 weeks of age, glucosuria was detected in all male and female FLS-Lep(ob)/Lep(ob) mice. Biochemical examination demonstrated that the FLS-Lep(ob)/Lep(ob) mice have severe hyperlipidemia and hyperinsulinemia. The livers of FLS-Lep(ob)/Lep(ob) mice showed microvesicular steatosis and deposition of large lipid droplets in hepatocytes throughout the lobules. The steatohepatitis-like lesions including the multifocal mononuclear cell infiltration and clusters of foamy cells were observed earlier in FLS-Lep(ob)/ Lep(ob) mice than in FLS mice. B6-Lep(ob)/Lep(ob) mice did not show hepatic inflammatory change. Furthermore, FLS-Lep(ob)/Lep(ob) mice developed multiple hepatic tumors including hepatocellular adenomas and carcinomas following steatohepatitis. In conclusion, the FLS-Lep(ob)/Lep(ob) mice developed steatohepatitis and hepatic tumors following hepatic steatosis. The FLS-Lep(ob)/Lep(ob) mouse with obesity and type 2 diabetes mellitus might be a useful animal model for human non-alcoholic steatohepatitis (NASH).

  13. Search for OB stars running away from young star clusters. II. The NGC 6357 star-forming region

    Science.gov (United States)

    Gvaramadze, V. V.; Kniazev, A. Y.; Kroupa, P.; Oh, S.

    2011-11-01

    Dynamical few-body encounters in the dense cores of young massive star clusters are responsible for the loss of a significant fraction of their massive stellar content. Some of the escaping (runaway) stars move through the ambient medium supersonically and can be revealed via detection of their bow shocks (visible in the infrared, optical or radio). In this paper, which is the second of a series of papers devoted to the search for OB stars running away from young ( ≲ several Myr) Galactic clusters and OB associations, we present the results of the search for bow shocks around the star-forming region NGC 6357. Using the archival data of the Midcourse Space Experiment (MSX) satellite and the Spitzer Space Telescope, and the preliminary data release of the Wide-Field Infrared Survey Explorer (WISE), we discovered seven bow shocks, whose geometry is consistent with the possibility that they are generated by stars expelled from the young (~1-2 Myr) star clusters, Pismis 24 and AH03 J1725-34.4, associated with NGC 6357. Two of the seven bow shocks are driven by the already known OB stars, HD 319881 and [N78] 34. Follow-up spectroscopy of three other bow-shock-producing stars showed that they are massive (O-type) stars as well, while the 2MASS photometry of the remaining two stars suggests that they could be B0 V stars, provided that both are located at the same distance as NGC 6357. Detection of numerous massive stars ejected from the very young clusters is consistent with the theoretical expectation that star clusters can effectively lose massive stars at the very beginning of their dynamical evolution (long before the second mechanism for production of runaway stars, based on a supernova explosion in a massive tight binary system, begins to operate) and lends strong support to the idea that probably all field OB stars have been dynamically ejected from their birth clusters. A by-product of our search for bow shocks around NGC 6357 is the detection of three circular

  14. Central stars of planetary nebulae. II. New OB-type and emission-line stars

    Science.gov (United States)

    Weidmann, W. A.; Gamen, R.

    2011-07-01

    Context. There are more than 3000 confirmed and probably known Galactic planetary nebulae (PNe), but central star spectroscopic information is available for only 13% of them. Aims: We have undertaken a spectroscopic survey of the central stars in PNe to identify their spectral types. Methods: We performed spectroscopic observations at low resolution with the 2-m telescope at CASLEO, Argentina. Results: We present the spectra of 46 central stars of PNe, most of them are OB-type and emission-line stars. Based on data collected at the Complejo Astronómico El Leoncito (CASLEO), which is operated under agreement between the Consejo Nacional de Investigaciones Científicas y Técnicas de la República Argentina y Universidades Nacionales de La Plata, Córdoba y San Juan, Argentina.The reduced spectra (FITS files) are available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/531/A172

  15. A photometric variability study of massive stars in Cygnus OB2

    CERN Document Server

    Salas, J; Barbá, R H

    2014-01-01

    We have conducted a 1.5 year-long variability study of the stars in the Cygnus OB2 association, the region in the northern hemisphere with the highest density of optically visible massive stars. The survey was conducted using four pointings in the Johnson $R$ and $I$ bands with a 35 cm Meade LX200-ACF telescope equipped with a 3.2 Mpixel SBIG ST10-XME CCD camera and includes 300+ epochs in each filter. A total of 1425 objects were observed with limiting magnitudes of 15 in $R$ and 14 in $I$. The photometry was calibrated using reference stars with existing $UBVJHK$ photometry. Bright stars have precisions better than 0.01 magnitudes, allowing us to detect 52 confirmed and 19 candidate variables, many of them massive stars without previous detections as variables. Variables are classified as eclipsing, pulsating, irregular/long period, and Be. We derive the phased light curves for the eclipsing binaries, with periods ranging from 1.3 to 8.5 days.

  16. On the observability of bow shocks of Galactic runaway OB stars

    CERN Document Server

    Meyer, D M -A; Kuiper, R; Kley, W

    2016-01-01

    Massive stars that have been ejected from their parent cluster and supersonically sailing away through the interstellar medium (ISM) are classified as exiled. They generate circumstellar bow shock nebulae that can be observed. We present two-dimensional, axisymmetric hydrodynamical simulations of a representative sample of stellar wind bow shocks from Galactic OB stars in an ambient medium of densities ranging from n_ISM=0.01 up to 10.0/cm3. Independently of their location in the Galaxy, we confirm that the infrared is the most appropriated waveband to search for bow shocks from massive stars. Their spectral energy distribution is the convenient tool to analyze them since their emission does not depend on the temporary effects which could affect unstable, thin-shelled bow shocks. Our numerical models of Galactic bow shocks generated by high-mass (~40 Mo) runaway stars yield H$\\alpha$ fluxes which could be observed by facilities such as the SuperCOSMOS H-Alpha Survey. The brightest bow shock nebulae are produc...

  17. No evidence for protoplanetary disk destruction by OB stars in the MYStIX sample

    CERN Document Server

    Richert, Alexander J W; Getman, Konstantin V; Kuhn, Michael A

    2015-01-01

    HST images of proplyds in the Orion Nebula, as well as submillimeter/radio measurements, show that the dominant O7 star Theta1 Ori C photoevaporates nearby disks around pre-main sequence stars. Theory predicts that massive stars photoevaporate disks within distances of order 0.1 pc. These findings suggest that young, OB-dominated massive H II regions are inhospitable to the survival of protoplanetary disks, and subsequently to the formation and evolution of planets. In the current work, we test this hypothesis using large samples of pre-main sequence stars in 20 massive star-forming regions selected with X-ray and infrared photometry in the MYStIX survey. Complete disk destruction would lead to a deficit of cluster members with excess in JHKs and Spitzer/IRAC bands in the vicinity of O stars. In four MYStIX regions containing O stars and a sufficient surface density of disk-bearing sources to reliably test for spatial avoidance, we find no evidence for the depletion of inner disks around pre-main sequence sta...

  18. Constraints on Massive Star Formation: Cygnus OB2 was always an Association

    CERN Document Server

    Wright, Nicholas J; Goodwin, Simon P; Drake, Jeremy J

    2013-01-01

    We examine substructure and mass segregation in the massive OB association Cygnus OB2 to better understand its initial conditions. Using a well understood Chandra X-ray selected sample of young stars we find that Cyg OB2 exhibits considerable physical substructure and has no evidence for mass segregation, both indications that the association is not dynamically evolved. Combined with previous kinematical studies we conclude that Cyg OB2 is dynamically very young, and what we observe now is very close to its initial conditions: Cyg OB2 formed as a highly substructured, unbound association with a low volume density (< 100 stars/pc^3). This is inconsistent with the idea that all stars form in dense, compact clusters. The massive stars in Cyg OB2 show no evidence for having formed particularly close to one another, nor in regions of higher than average density. Since Cyg OB2 contains stars as massive as ~100 Mo this result suggests that very massive stars can be born in relatively low-density environments. Thi...

  19. A Novel Congestion Detection Scheme in TCP Over OBS Networks

    KAUST Repository

    Shihada, Basem

    2009-02-01

    This paper introduces a novel congestion detection scheme for high-bandwidth TCP flows over optical burst switching (OBS) networks, called statistical additive increase multiplicative decrease (SAIMD). SAIMD maintains and analyzes a number of previous round-trip time (RTTs) at the TCP senders in order to identify the confidence with which a packet loss event is due to network congestion. The confidence is derived by positioning short-term RTT in the spectrum of long-term historical RTTs. The derived confidence corresponding to the packet loss is then taken in the developed policy for TCP congestion window adjustment. We will show through extensive simulation that the proposed scheme can effectively solve the false congestion detection problem and significantly outperform the conventional TCP counterparts without losing fairness. The advantages gained in our scheme are at the expense of introducing more overhead in the SAIMD TCP senders. Based on the proposed congestion control algorithm, a throughput model is formulated, and is further verified by simulation results.

  20. The interstellar medium towards the Ara OB1 region

    CERN Document Server

    Henderson, Christopher D; Hearnshaw, John B

    2008-01-01

    We present high resolution (R ~ 4 km/s) absorption measurements of the interstellar NaI and CaII lines measured towards 14 early-type stars of distance 123 pc - 1650 pc, located in the direction of the Ara OB1 stellar cluster. The line profiles can broadly be split into four distinct groupings of absorption component velocity, and we have attempted to identify an origin and distance to each of these interstellar features. For gas with absorption covering the velocity range -10 km/s < V_helio < +10 km/s, we can identify the absorbing medium with local gas belonging to the Lupus-Norma interstellar cavity located between 100 and 485 pc in this galactic direction. Gas with velocities spanning the range -20 km/s < V_helio < +20 km/s is detected towards stars with distances of 570-800 pc. We identify a wide-spread interstellar feature at V_helio ~ -15 km/s with the expanding HI shell called GSH 337+00-05, which is now placed at a distance of ~530 pc.

  1. D Recording of a 19-CENTURY OB River Ship

    Science.gov (United States)

    Pushkarev, A. A.; Zaytceva, O. V.; Vavulin, M. V.; Skorobogatova, A. Y.

    2016-06-01

    A 3D recording of a 19-century wooden ship discovered on the bank of the river Ob (Western Siberia) was performed in autumn 2015. The archaeologized ship was partly under water, partly lying ashore, buried under fluvial deposits. The 3D recording was performed in October, when the water level was at its lowest after clearing the area around the ship. A 3D recording at the place of discovery was required as part of the ship museumification and reconstruction project. The works performed were primarily aimed at preserving as much information about the object as possible. Given the location and peculiar features of the object, a combination of close-range photogrammetry and aerial photography was considered to be the best possible solution for creating a high-quality 3D model. The dismantled ship was delivered to Nizhnevartovsk Museum of Local History in October 2015. The ship is going to be reassembled using the created 3D model to be exhibited in the museum. The resulting models are also going to be used to make a virtual 3D reconstruction of the ship in the future. We shot a stereoscopic video for Nizhnevartovsk Museum of Local History to let visitors see the place of discovery and explore the ship in greater details. Besides, 3D printing allowed for creating a miniature of the ship, which is also going to be included in the exposition devoted to this unique discovery.

  2. 3D RECORDING OF A 19-CENTURY OB RIVER SHIP

    Directory of Open Access Journals (Sweden)

    A. A. Pushkarev

    2016-06-01

    Full Text Available A 3D recording of a 19-century wooden ship discovered on the bank of the river Ob (Western Siberia was performed in autumn 2015. The archaeologized ship was partly under water, partly lying ashore, buried under fluvial deposits. The 3D recording was performed in October, when the water level was at its lowest after clearing the area around the ship. A 3D recording at the place of discovery was required as part of the ship museumification and reconstruction project. The works performed were primarily aimed at preserving as much information about the object as possible. Given the location and peculiar features of the object, a combination of close-range photogrammetry and aerial photography was considered to be the best possible solution for creating a high-quality 3D model. The dismantled ship was delivered to Nizhnevartovsk Museum of Local History in October 2015. The ship is going to be reassembled using the created 3D model to be exhibited in the museum. The resulting models are also going to be used to make a virtual 3D reconstruction of the ship in the future. We shot a stereoscopic video for Nizhnevartovsk Museum of Local History to let visitors see the place of discovery and explore the ship in greater details. Besides, 3D printing allowed for creating a miniature of the ship, which is also going to be included in the exposition devoted to this unique discovery.

  3. Microstructural analyses of B{sub 4}C-CeO{sub 2} and B{sub 4}C-La{sub 2}O{sub 3} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sakamoto, Tatsuaki, E-mail: sakamoto.tatsuaki@eng.ehime-u.ac.jp [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Sun, Shu-Chen [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Furuno, Tomoya; Kajioka, Michio [Graduate Student of Ehime Univerisity, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Nakai, Kiyomichi [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Kurishita, Hiroaki [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Kobayashi, Sengo [Department of Materials Science and Biotechnology, Ehime University, 3 Bunkyo-cho, Matsuyama 790-8577 (Japan); Wu, Wen-Yuan; Tu, Gan-Feng [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Matsuda, Seiji [Department of Anatomy and Embryology, Ehime University, Shizugawa, Toon 791-0295 (Japan)

    2011-10-01

    Effects of additions of CeO{sub 2} and La{sub 2}O{sub 3} on microstructure and mechanical properties of B{sub 4}C fabricated under and without hot press have been investigated. Vickers hardness and fracture strength are increased by hot press due to the reduction of porosity because the sintering rate is enhanced. Hardness is increased by the reduction of porosity because crack probably occurs when the hardness is measured due to pore as an initiation point of crack. Hardness increases with increasing additions of CeO{sub 2} and La{sub 2}O{sub 3} because porosity decreases due to the formation of CeB{sub 6} and LaB{sub 6} on the grain boundary of B{sub 4}C, respectively. The borides are formed through reaction between solid phases, which might induce coherent boundary between boride and B{sub 4}C. Such coherency also contributes to strengthening the grain boundary of B{sub 4}C. The addition of CeO{sub 2} enhances the sintering rate more than that of La{sub 2}O{sub 3}, resulting in higher hardness of B{sub 4}C-CeO{sub 2} than that of B{sub 4}C-La{sub 2}O{sub 3}.

  4. Attenuated pain response of obese mice (B6.Cg-lep(ob)) is affected by aging and leptin but not sex.

    Science.gov (United States)

    Rodgers, Helen M; Liban, Suadi; Wilson, Linda M

    2014-01-17

    Genetically obese mice (B6.Cg-lep(ob)) manifest decreased responses to noxious thermal stimuli (hotplate test) suggesting endogenous analgesia (Roy et al., 1981). To examine further the analgesic response of these mice, we conducted 4 experiments. Experiment 1 assessed the response of ob/ob mice to tail flick, another noxious thermal test. Tail-flick testing was performed on B6.Cg-lep(ob) mice (n=14) and B6.Cg-lep(OB/?) (n=12) across a range of temperatures. Ob/ob mice exhibited longer latencies than control mice at all temperatures tested. In Experiment 2, potential sex differences were examined. Tail-flick latencies in male and female ob/ob mice (n=6/group) did not differ. The final 2 experiments examined factors that could modulate endogenous analgesia. Experiment 3 assessed the effects of aging in ob/ob mice (n=10/group). Older mice displayed longer tail-flick latencies than did younger mice. Experiment 4 examined the effect of leptin administration in the leptin-deficient ob/ob mice. Two groups (n=10/group) of ob/ob mice received osmotic pump implants filled with either leptin or vehicle, and were tail-flick tested at days 7 and 14 post-implantation. Ob/ob mice receiving leptin showed shorter latencies than did vehicle-receiving ob/ob mice. Taken together, these results support earlier reports of heightened analgesia in ob/ob mice and suggest that aging further reduces the already impaired pain response. Furthermore, leptin deficiency partially contributes to decreased pain sensation of ob/ob mice.

  5. Expression of the P2X2 receptor in different classes of ileum myenteric neurons in the female obese ob/ob mouse

    Institute of Scientific and Technical Information of China (English)

    Márcia Sanae Mizuno; Amanda Rabello Crisma; Primavera Borelli; Patricia Castelucci

    2012-01-01

    AIM:To examine whether the ob/ob mouse model of obesity is accompanied by enteric nervous system abnormalities such as altered motility.METHODS:The study examined the distribution of the P2X2 receptor (P2X2R) in myenteric neurons of female ob/ob mice.Specifically,we used immunohistochemistry to analyze the co-expression of the P2X2R with neuronal nitric oxide synthase (nNOS),choline acetyltransferase (ChAT),and calretinin (CalR) in neurons of the small intestine myenteric plexus in ob/ob and control female mice.In these sections,we used scanning confocal microscopy to analyze the co-localization of these markers as well as the neuronal density (cm2) and area profile (μm2) of P2X2R-positive neurons.In addition,enteric neurons were labeled using the nicotinamide adenine dinucleotide (NADH) diaphorase method and analyzed with light microscopy as an alternate means by which to analyze neuronal density and area.RESULTS:In the present study,we observed a 29.6% increase in the body weight of the ob/ob animals (OG)compared to the control group (CG).In addition,the average small intestine area was increased by approximately 29.6% in the OG compared to the CG.Immunoreactivity (IR) for the P2X2R,nNOS,ChAT and CalR was detectable in the myenteric plexus,as well as in the smooth muscle,in both groups.This IR appeared to be mainly cytoplasmic and was also associated with the cell membrane of the myenteric plexus neurons,where it outlined the neuronal cell bodies and their processes.P2X2R-IR was observed to co-localize 100% with that for nNOS,ChAT and CalR in neurons of both groups.In the ob/ob group,however,we observed that the neuronal density (neuron/cm2) of P2X2R-IR cells was increased by 62% compared to CG,while that of NOS-IR and ChAT-IR neurons was reduced by 49% and 57%,respectively,compared to control mice.The neuronal density of CalR-IR neurons was not different between the groups.Morphometric studies further demonstrated that the cell body profile area (

  6. 某医院护士专业自我概念与职业倦怠和离职意愿的相关性调查%A survey on thecorrelation of nurses professional self-concept on j ob burnout and turnover intention in a hospital

    Institute of Scientific and Technical Information of China (English)

    白琼

    2016-01-01

    目的探讨护士的专业自我概念对护士职业倦怠、离职意愿的影响。方法2014年10月,选取某医院护士492名,采用专业自我概念量表、职业倦怠问卷量表和离职意愿量表进行匿名问卷调查。结果护士中出现职业倦怠的比例高达77.64%,职业倦怠护士在情感耗竭(27.15±7.18)、去人格化(9.32±4.07)、职业效能(18.76±7.61)3个维度方面与无职业倦怠护士对比差异有统计学意义(P<0.05),且护士的护龄越长、学历越高、加班时间越久,职业倦怠情况越严重(P<0.05)。护士中具有离职意愿的比例达80%,且离职意愿随着学历、加班时间呈上升趋势(P<0.05),随着护龄呈下降趋势(P<0.05)。具有职业倦怠和离职意愿的护士的专业自我概念与无职业倦怠、无离职意愿比较,差异有统计学意义(P<0.05)。结论护士的专业自我概念与职业倦怠、离职意愿均呈高度相关,可对护士的职业倦怠、离职意愿采取针对性的干预措施,增强护士的专业自我评分。%Objective To explore the impact of nurses�professional self-concept on occupational burnout and turnover intention.Methods 492 nurses were chosen in a hospital in October 2014,and anonymous questionnaire survey of the nurses� professional self-concept,job burnout and turnover intention were conducted.Results The prevalence of the job burnout among the nurses were 77.64% and the score of the emotional exhaustion(27.15±7.18),depersonalization(9.32±4.07)and professional efficacy(18.76±7.61) in 3 articles of job burnout questionnaire were significantly worse than the score of nurse with no job burnout (P<0.05).The longer of working year and working overtime,the higher educational attainment,the more serious situation of the job burnout(P<0.05).The will of turnover in the nurses was almost 80%,and increased with higher educational attainment and longer working overtime were (P<0.05),while declined with longer

  7. Divergent effects of a CLA-enriched beef diet on metabolic health in ApoE-/- and ob/ob mice.

    Science.gov (United States)

    Reynolds, Clare M; Toomey, Sinead; McBride, Rachael; McMonagle, Jolene; Morine, Melissa J; Belton, Orina; Moloney, Aidan P; Roche, Helen M

    2013-02-01

    Conjugated linoleic acid (CLA) is found naturally in meat and dairy products, and represents a potential therapeutic functional nutrient. However, given the discrepancies in isomer composition and concentration, controversy surrounds its proposed antidiabetic, antiobesity effects. This study focused on the effects of CLA-enriched beef (composed predominantly of c9, t11-CLA) in two separate models of metabolic disease: proatherosclerotic ApoE(-/-) mice and diabetic, leptin-deficient ob/ob mice. Animals were fed CLA-enriched beef for 28 days, and markers of the metabolic syndrome and atherosclerosis were assessed. Comprehensive hepatic transcriptomic analysis was completed to understand divergent metabolic effects of CLA. CLA-enriched beef significantly reduced plasma glucose, insulin, nonesterified fatty acid and triacylglycerol and increased adiponectin levels in ob/ob mice. In contrast, plasma lipid profiles and glucose homeostasis deteriorated and promoted atherosclerosis following the CLA-enriched beef diet in ApoE(-/-) mice. Hepatic transcriptomic profiling revealed divergent effects of CLA-enriched beef on insulin signaling and lipogenic pathways, which were adversely affected in ApoE(-/-) mice. This study demonstrated clear divergence in the effects of CLA. CLA-enriched beef improved metabolic flexibility in ob/ob mice, resulting in enhanced insulin sensitivity. However, CLA-enriched diet increased expression of lipogenic genes, resulting in inefficient fatty acid storage which increases lipotoxicity in peripheral organs, and led to profound metabolic dysfunction in ApoE(-/-) mice. While CLA may have potential health effects, in some circumstances, caution must be exercised in presenting this bioactive lipid as a potential functional food for the treatment of metabolic disease.

  8. Characterization of NCAM expression and function in BT4C and BT4Cn glioma cells

    DEFF Research Database (Denmark)

    1991-01-01

    -substratum binding assay in which the binding of BT4C and BT4Cn cells to NCAM immobilized to glass was assessed. We found that BT4C cells adhere specifically to NCAM, and that adhesion is inhibited by anti-NCAM Fab'-fragments, while no specific binding of BT4Cn cells to NCAM was observed. The BT4C and BT4Cn cell...

  9. The role of eIF-4C in protein synthesis initiation complex formation

    NARCIS (Netherlands)

    Goumans, H.; Thomas, A.; Verhoeven, H.; Voorma, H.O.; Benne, R.

    1980-01-01

    eIF-4C has a pronounced stimulatory effect on initiation complex formation with native 80-S ribosomes (80-Sn) as the only source of ribosomal subunits, but only a small effect when washed 40-S subunits are used. eIF-4C is accessary to eIF-3 in dissociating 80-Sn ribosomes. eIF-4C is present on 40-

  10. 32 CFR 1630.42 - Class 4-C: Alien or dual national.

    Science.gov (United States)

    2010-07-01

    ... 32 National Defense 6 2010-07-01 2010-07-01 false Class 4-C: Alien or dual national. 1630.42... CLASSIFICATION RULES § 1630.42 Class 4-C: Alien or dual national. In Class 4-C shall be placed any registrant who... service in the United States. (b) Is an alien and who has departed from the United States prior to...

  11. Emodin, an 11β-hydroxysteroid dehydrogenase type 1 inhibitor, regulates adipocyte function in vitro and exerts anti-diabetic effect in ob/ob mice

    Institute of Scientific and Technical Information of China (English)

    Yue-jing WANG; Su-ling HUANG; Ying FENG; Meng-meng NING; Ying LENG

    2012-01-01

    Aim:Emodin (1,3,8-trihydroxy 6-methylanthraquinone) is a potent and selective inhibitor of 11β-hydroxysteroid dehydrogenase type 1 (11β-HSD1) with the ability to ameliorate metabolic disorders in diet-induced obese mice.In the present study,we investigated the effects of emodin on adipocyte function and the underlying mechanisms in vitro,and its anti-diabetic effects in ob/ob mice.Methods:3T3-L1 adipocytes were used for in vitro studies.11β-HSD1A activity was evaluated with a scintillation proximity assay.The adipogenesis,glucose uptake,lipolysis and adiponectin secretion were investigated in 3T3-L1 adipocytes treated with emodin in the presence of active (corticosterone) or inactive glucocorticoid (11-dehydrocorticosterone).For in vivo studies,ob/ob mice were administered emodin (25 and 50 mg.kg-1·d-1,ip) for 26 d.On the last day of administration,the serum was collected and the mesenteric and perirenal fat were dissected for analyses.Results:Emodin inhibited the 11β-HSD1 activity in 3T3-L1 adipocytes in concentration- and time dependent manners (the IC50 values were 7,237 and 4.204 μmol/L,respectively,after 1 and 24 h treatment,in 3T3-L1 adipocytes,emodin (30 μmol/L) suppressed 11-dehydrocorticosterone-induced adipogenesis without affecting corticosterone-induced adipogenesis; emodin (3 μmol/L) reduced 11-dehydrocorticosterone-stimulated lipolysis,but had no effect on corticosterone-induced lipolysis.Moreover,emodin (3 μmol/L)partly reversed the impaired insulin-stimulated glucose uptake and adiponectin secretion induced by 11-dehydrocorticosterone but not those induced by corticosterone.In ob/ob mice,long-term emodin administration decreased 11β-HSD1 activity in mesenteric adipose tissues,lowered non-fasting and fasting blood glucose levels,and improved glucose tolerance.Conclusion:Emodin improves the inactive glucocorticoid-induced adipose tissue dysfunction by selective inhibition on 11β-HSD1 in adipocyte in vitro and improves glycemic control in ob/ob

  12. Enzyme kinetic studies of histone demethylases KDM4C and KDM6A

    DEFF Research Database (Denmark)

    Kristensen, Jan B L; Nielsen, Anders L; Jørgensen, Lars;

    2011-01-01

    To investigate ligand selectivity between the oncogenic KDM4C and tumor repressor protein KDM6A histone demethylases, KDM4C and KDM6A were enzymatically characterized, and subsequently, four compounds were tested for inhibitory effects. 2,4-dicarboxypyridine and (R)-N-oxalyl-O-benzyltyrosine (3......) are both known to bind to a close KDM4C homolog and 3 binds in the part of the cavity that accommodates the side chain in position 11 of histone 3. The inhibition measurements showed significant selectivity between KDM4C and KDM6A. This demonstrates that despite very similar active site topologies...

  13. Comparative Precise Parameters for OB Stars in Three Galaxies

    Science.gov (United States)

    Walborn, Nolan

    2014-10-01

    The chemical abundances, wind terminal velocities, and mass-loss rates of OB stars in the Small and Large Magellanic Clouds will be determined homogeneously from high-resolution spectroscopic data in the Mikulski Archive; and they will be further compared with analogous determinations in the Solar Neighborhood. As is well known, the three systems offer a metallicity sequence with values in solar units generally given as 0.2, 0.5, and 1, respectively, which should have corresponding effects on the metallic-line-driven winds. However, the quantitative basis for that general result can and should be improved for various reasons. For instance, it is based on heterogeneous analyses, some dated, of data with varying quality. Moreover, there is not a single metallicity but different relative values for different elements, seldom available for individual stars, with CNO significantly affected by internal evolutionary processes. We propose advances with state-of-the-art analyses of the best data, primarily from STIS and COS in the UV, but also incorporating FUSE observations of the same stars, and IUE high-resolution of a few. We shall also analyze correlative groundbased optical data. J-CB and collaborators have already published recent results for Galactic supergiants and SMC dwarfs, while work on the SMC giants/supergiants is in progress. We shall build upon that work with further Galactic and SMC data, and especially with the still relatively small but significant LMC UV sample, with detailed spectral-type matching insofar as possible. We shall also produce an atlas of all spectra analyzed, to be placed in the Archive as a high-level product to guide future work.

  14. Abortion training to be required in standard Ob / Gyn curriculum.

    Science.gov (United States)

    1995-02-24

    On February 15, (1995) the Accreditation Council for Graduate Medical Education announced that it will now require medical schools seeking accreditation to provide abortion training for all residents in obstetrics and gynecology. The new "Program Requirements for Residency Education in Obstetrics and Gynecology," approved unanimously, will take effect on January 1, 1996. According to the Council, the newly issued standards are the first to refer specifically to abortion. The language states, "Experience with induced abortion must be part of residency training, except for residents with moral or religious objections .... Experience with management of complications of abortion must be provided to all residents." The Council also mandates that if a medical school itself has "a religious, moral or legal" objection to teaching the procedure, it must "ensure that residents ... who do not have a religious or moral objection receive education and experience in performing abortion at another institution." Other revisions provide for expanded resident education in "primary and preventive care," due to the fact that many women rely on their obstetricians and gynecologists as their primary care physicians, as well as additional training experience in family planning, including "all reversible methods of contraception" and sterilization. In order to be certified by the American Board of Obstetrics and Gynecology, ob/gyns must graduate from an accredited residency program. In addition, teaching hospitals must be accredited to secure federal reimbursements for the medical services patients receive from residents. The Accreditation Council for Graduate Medical Education operates under the aegis of the American Medical Association, the American Board of Medical Specialties, the American Hospital Association, the Association of American Medical Colleges, and the Council of Medical Specialty Societies. Both the American Board of Obstetrics and Gynecology and the American College of

  15. OB-RL silencing inhibits the thermoregulatory ability of Great Roundleaf Bats (Hipposideros armiger).

    Science.gov (United States)

    Zhu, Tengteng; Yuan, Lihong; Jones, Gareth; Hua, Panyu; He, Guimei; Chen, Jinping; Zhang, Shuyi

    2014-08-01

    Previous studies have shown that the hormone Leptin has an important role in mammalian heterothermy by regulating metabolism and food intake via lipolysis, as well as adaptive evolution of Leptin in heterothermic bats driven by selected pressure. However, the mechanism of Leptin in heterothermic regulation in mammals is unknown. By combining previous results, we speculated that the Leptin signaling pathway mediated by OB-RL (Leptin receptor long form) in the hypothalamus is important. OB-RL is one of the products of db gene and mainly distributed in the hypothalamus. In this study, we used OB-RL as a molecular marker, combining with the RNA interference technology and physiological/molecular analyses with Hipposideros armiger (a hibernating bat species) as an animal model, to explore the mechanism of Leptin in heterothermic regulation. Our data showed that all of four anti-OB-RL shRNA lentivirus significantly inhibited OB-RL expression (>90%), and the interference efficiency of PSC1742 lentivirus reached the highest value. In situ hybridization proved that PSC1742 lentivirus significantly decreased the OB-RL expression in the hypothalamus, especially in the ventromedial hypothalamic nucleus (VHM, 86.6%). Physiological analysis demonstrated that the thermoregulatory ability of bats (e.g., reducing core body temperature and heart rate) was significantly depressed after OB-RL silencing in the hypothalamus, and animals could not enter torpor state. Our study for the first time proved that the knock-down of OB-RL expression in hypothalamus inhibits heterothermic regulation of bats, and also provided the clues for further analyzing the mechanism of Leptin in the heterothermic regulation of mammals.

  16. PARTICLE SIZE-DEPENDENT PULVERIZATION OF B4C AND GENERATION OF B4C/STS NANOPARTICLES USED FOR NEUTRON ABSORBING COMPOSITES

    Directory of Open Access Journals (Sweden)

    JAEWOO KIM

    2014-10-01

    Full Text Available Pulverization of two different sized micro-B4C particles (∼10 μm and ∼150 μm was investigated using a STS based high energy ball milling system. Shapes, generation of the impurities, and reduction of the particle size dependent on milling time and initial particle size were investigated using various analytic tools including SEM-EDX, XRD, and ICP-MS. Most of impurity was produced during the early stage of milling, and impurity content became independent on the milling time after the saturation. The degree of particle size reduction was also dependent on the initial B4C size. It was found that the STS nanoparticles produced from milling is strongly bounded with the B4C particles forming the B4C/STS composite particles that can be used as a neutron absorbing nanocomposite. Based on the morphological evolution of the milled particles, a schematic pulverization model for the B4C particles was constructed.

  17. ALASKA1964_OBS - Alaska 1964 Tsunami Observations at Seaside, Oregon

    Data.gov (United States)

    U.S. Geological Survey, Department of the Interior — This data set is a point shapefile representing observations of inundation and water levels from the Alaska 1964 event obtained by Tom Horning (1997). The geospatial...

  18. A Catalog of New Spectroscopically Confirmed Massive OB Stars in Carina

    CERN Document Server

    Alexander, Michael J; Povich, Matthew S; McSwain, M Virginia

    2016-01-01

    The Carina star-forming region is one of the largest in the Galaxy, and its massive star population is still being unveiled. The large number of stars combined with high, and highly variable, interstellar extinction makes it inherently difficult to find OB stars in this type of young region. We present the results of a spectroscopic campaign to study the massive star population of the Carina Nebula, with the primary goal to confirm or reject previously identified Carina OB star candidates. A total of 141 known O- and B-type stars and 94 candidates were observed, of which 73 candidates had a high enough signal-to-noise ratio to classify. We find 23 new OB stars within the Carina Nebula, a 32% confirmation rate. One of the new OB stars has blended spectra and is suspected to be a double-lined spectroscopic binary (SB2). We also reclassify the spectral types of the known OB stars and discover nine new SB2s among this population. Finally, we discuss the spatial distribution of these new OB stars relative to known...

  19. Osteoarthitis of Leptin-Deficient ob/ob Mice in Response to Biomechanical Loading in Micro-CT

    Directory of Open Access Journals (Sweden)

    Hansjoerg Heep, Gero Hilken, Sebastian Hofmeister, Christian Wedemeyer

    2009-01-01

    Full Text Available Objective: Mechanotransduction is the mechanism that due to reacting chondrocytes on biomechanical loading of body mass. Higher biomechanical loading lead to increased degeneration of chondrocytes, whereas moderate loading is protecting. This suggests that body fat regulates bone metabolism first by means of hormonal factors and second that the effects of muscle and loading are signaling factors in mechanotransduction. Leptin, a peptide hormone produced predominantly by white fat cells, is one of these hormonal factors. The aim of this study was to investigate and measure the different effects of weight-bearing on trabecular bone formation in mice without the stimulation of leptin and with or without osteoarthritis. Materials and methods: 40 C57BL/ 6J ob/ob-mice in the age of 20 weeks have been devided into two groups with an ad-libitum-diet and with reduced diet. The hip- and knee-joints have been examinated in micro-CT-scan and histomorphologically. Results: Animals with an ad-libitum-diet were found to increase body weight significantly at the age of six weeks in comparison with lean mice. At the age of twenty weeks the obese mice were almost twice as heavy as the lean mice. Significant statistical differences are shown between the two groups for body weight and bone mineral density. Examination of trabecular bone in micro-CT revealed that the only statistically significant difference between the two groups was the trabecular number for the proximal femur. High weight-bearing insignificantly improved all trabecular bone parameters in the obese mice. Correlation was found between trabecular number and bone mineral density on the one hand and body weight on the other hand. The correlation between body weight and osteoarthritis shows a significant increase in grade of osteoarthritis as body weight increases in hip-joint and knee-joint but not in osteoarthritis-positive (OP versus osteoarthritis-negative (ON mices. The correlation of the hip

  20. Microstructures and mechanical properties in B{sub 4}C-CeO{sub 2} ceramics

    Energy Technology Data Exchange (ETDEWEB)

    Sun Shuchen, E-mail: sunsc@smm.neu.edu.cn [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Sakamoto, Tatsuaki; Nakai, Kiyomichi [Department of Materials Science and Biotechnology, Ehime University, 3Bunkyo-cho, Matsuyama 790-8577 (Japan); Kurishita, Hiroaki [International Research Center for Nuclear Materials Science, Institute for Materials Research, Tohoku University, Oarai, Ibaraki 311-1313 (Japan); Kobayashi, Sengo [Department of Materials Science and Biotechnology, Ehime University, 3Bunkyo-cho, Matsuyama 790-8577 (Japan); Xu Jingyu; Cao Hui; Gao Bo; Bianxue; Wu Wenyuan; Tu Ganfeng [School of Materials and Metallurgy, Northeastern University, Shenyang 110004 (China); Matsuda, Seiji [Department of Anatomy and Embryology, Ehime University, Shizugawa, Toon 791-0295 (Japan)

    2011-10-01

    B{sub 4}C-CeO{sub 2} composite ceramics with various concentrations of CeO{sub 2} were fabricated by hot press. The effects of CeO{sub 2} on the microstructures and mechanical properties of the B{sub 4}C-CeO{sub 2} ceramics have been investigated. During hot press, CeB{sub 6} was formed by the reaction between CeO{sub 2} and B{sub 4}C. The B{sub 4}C-CeO{sub 2} ceramics had higher levels of density, fracture toughness, flexural strength and Vickers hardness than those in monolithic B{sub 4}C. The microstructures of the B{sub 4}C-CeO{sub 2} ceramics were observed and analyzed by transmission electron microscopy. In-situ synthesized CeB{sub 6} indicated whisker-like shape and grew along the interface with B{sub 4}C, and different boron carbides with different content of C existed at/around the interface of CeB{sub 6} with B{sub 4}C in the composite ceramics. It made mechanical properties greatly improved.

  1. Synthesis and Electrochemical Properties of LiFePO4/C for Lithium Ion Batteries.

    Science.gov (United States)

    Gao, Hong; Wang, Jiazhao; Yin, Shengyu; Zheng, Hao; Wang, Shengfu; Feng, Chuanqi; Wang, Shiquan

    2015-03-01

    LiFePO4/C was prepared through a facile rheological phase reaction method by using Fe3(PO4)2, Li3PO4 · 8H2O, and glucose as reactants. The LiFePO4/C samples were characterized by X-ray diffraction, scanning electron microscopy, and thermogravimetric analysis. The electrochemical properties of the samples were investigated. The results show that the LiFePO4/C samples have single-phase olivine-type structure, and their particles feature a spherical shape. The carbon coating on the particles of LiFePO4 is about 1.8% of the LiFePO4/C by weight. The particle size was distributed from 0.2 to 1 µm. The initial discharge capacity of LiFePO4/C reached 154 mA h/g at 0.1 C. The retained discharge capacity of LiFePO4/C was 152.9 mA h g(-1) after 50 cycles. The LiFePO4/C also showed better cycling performance than that of the bare LiPeO4 at a higher charge/discharge rate (1 C). The LIFePO4/C prepared in this way could be a promising cathode material for lithium ion battery application.

  2. Integration and communication for the continuity of cardiac care (I4C)

    NARCIS (Netherlands)

    Bemmel, J.H. van; Ginneken, A.M. van; Stam, H.; Assanelli, D.; Macfarlane, P.W.; Maglaveras, N.; Rubel, P.; Zeelenberg, C.; Zywietz, Chr.

    1998-01-01

    The project I4C (Integration and Communication for the Continuity of Cardiac Care) is carried out for the advancement of cardiac care, from prevention to follow-up. The goals of I4C are: (1) integrated access to patient data, wherever they are stored; (2) support of evidence-based care; (3) consiste

  3. Pycnogenol supplementation promotes lipolysis via activation of cAMP-dependent PKA in ob/ob mice and primary-cultured adipocytes.

    Science.gov (United States)

    Ho, Jin-Nyoung; Kim, Ok-Kyung; Nam, Da-Eun; Jun, Woojin; Lee, Jeongmin

    2014-01-01

    This study investigated the PKA-dependent inhibitory effect of pycnogenol (Pyc) on lipolysis using ob/ob mice and primary mouse adipocytes. Supplementation of Pyc at 30 mg/kg significantly reduced body weight gain and visceral fat mass. The serum and hepatic triglyceride (TG) and total cholesterol (TC) levels were reduced by Pyc supplementation, and high density lipoprotein (HDL)-cholesterol level significantly increased. In addition, hormone sensitive lipase (HSL) and adipose triglyceride lipase (ATGL) mRNA levels increased with Pyc supplementation in adipose tissue of ob/ob mice. The treatment of primary cultured adipocytes with Pyc at 100 μg/mL significantly increased glycerol release, cAMP level by reduction of phosphodiestersae-3B (PDE3B), and HSL levels, but decreased protein levels of perilipin A and fatty acid synthetase (FAS). The PKA inhibitor (H89) clearly blocked the cellular levels of perilipin A and HSL, suggesting that Pyc promotes lipolysis of adipocytes through activation of cAMP-dependent PKA, resulting in induction of HSL and reduction of perilipin A. Therefore, this study may elucidate the possible mechanism of Pyc, which is a candidate for weight loss through stimulation of lipolysis.

  4. (CH4)-C-14 Measurements in Greenland Ice: Investigating Last Glacial Termination CH4 Sources

    DEFF Research Database (Denmark)

    Petrenko, V. V.; Smith, A. M.; Brook, E. J.;

    2009-01-01

    The cause of a large increase of atmospheric methane concentration during the Younger Dryas-Preboreal abrupt climatic transition (similar to 11,600 years ago) has been the subject of much debate. The carbon-14 (C-14) content of methane ((CH4)-C-14) should distinguish between wetland and clathrate...... contributions to this increase. We present measurements of (CH4)-C-14 in glacial ice, targeting this transition, performed by using ice samples obtained from an ablation site in west Greenland. Measured (CH4)-C-14 values were higher than predicted under any scenario. Sample (CH4)-C-14 appears to be elevated...... by direct cosmogenic C-14 production in ice. C-14 of CO was measured to better understand this process and correct the sample (CH4)-C-14. Corrected results suggest that wetland sources were likely responsible for the majority of the Younger Dryas-Preboreal CH4 rise....

  5. Comparative Study on the Marketing Theories of 4P and 4C%4P 与4C 营销理论的比较研究

    Institute of Scientific and Technical Information of China (English)

    尹坤; 李欣

    2015-01-01

    The marketing theories of 4P and 4C can’t be replaced by each other from the perspectives of the theories and the application related with the origination and development of marketing mix.They are origi-nated in different marketing environment and are not contradicted in essence.Hence,it is claimed that the theories of 4P and 4C should be mixed in application according to the industry peculiarities,market compe-tition condition and the different stages of the products.%从营销组合的产生与发展以及理论和应用层面分析认为,4P 和4C 营销理论之间不存在谁取代谁的关系,它们产生于不同的营销环境,没有本质的矛盾。在此基础上提出应该根据具体的行业特征、市场竞争状况和产品所处的不同的生命周期阶段来对4P 和4C 进行组合运用。

  6. NEAR-INFRARED VARIABILITY AMONG YOUNG STELLAR OBJECTS IN THE STAR FORMATION REGION CYGNUS OB7

    Energy Technology Data Exchange (ETDEWEB)

    Wolk, Scott J.; Rice, Thomas S. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Aspin, Colin [Institute for Astronomy, University of Hawaii at Manoa, 640 North Aohoku Place, Hilo, HI 96720 (United States)

    2013-08-20

    We present an analysis of near-infrared time-series photometry in J, H, and K bands for about 100 epochs of a 1 Degree-Sign Multiplication-Sign 1 Degree-Sign region of the Lynds 1003/1004 dark cloud in the Cygnus OB7 region. Augmented by data from the Wide-field Infrared Survey Explorer, we identify 96 candidate disk bearing young stellar objects (YSOs) in the region. Of these, 30 are clearly Class I or earlier. Using the Wide-Field Imaging Camera on the United Kingdom Infrared Telescope, we were able to obtain photometry over three observing seasons, with photometric uncertainty better than 0.05 mag down to J Almost-Equal-To 17. We study detailed light curves and color trajectories of {approx}50 of the YSOs in the monitored field. We investigate the variability and periodicity of the YSOs and find the data are consistent with all YSOs being variable in these wavelengths on timescales of a few years. We divide the variability into four observational classes: (1) stars with periodic variability stable over long timescales, (2) variables which exhibit short-lived cyclic behavior, (3) long-duration variables, and (4) stochastic variables. Some YSO variability defies simple classification. We can explain much of the observed variability as being due to dynamic and rotational changes in the disk, including an asymmetric or changing blocking fraction, changes to the inner disk hole size, as well as changes to the accretion rate. Overall, we find that the Class I:Class II ratio of the cluster is consistent with an age of <1 Myr, with at least one individual, wildly varying source {approx}100, 000 yr old. We have also discovered a Class II eclipsing binary system with a period of 17.87 days.

  7. Preparedness of Ob/Gyn residents for fellowship training in gynecologic oncology

    Directory of Open Access Journals (Sweden)

    David W. Doo

    2015-04-01

    Full Text Available Residency training in obstetrics and gynecology is being challenged by increasingly stringent regulations and decreased operative experience. We sought to determine the perception of preparedness of incoming gynecologic oncology fellows for advanced surgical training in gynecologic oncology. An online survey was sent to gynecologic oncologists involved in fellowship training in the United States. They were asked to evaluate their most recent incoming clinical fellows in the domains of professionalism, level of independence/graduated responsibility, psychomotor ability, clinical evaluation and management, and academia and scholarship using a standard Likert-style scale. The response rate among attending physicians was 40% (n = 105/260 and 61% (n = 28/46 for program directors. Of those who participated, 49% reported that their incoming fellows could not independently perform a hysterectomy, 59% reported that they could not independently perform 30 min of a major procedure, 40% reported that they could not control bleeding, 40% reported that they could not recognize anatomy and tissue planes, and 58% reported that they could not dissect tissue planes. Fellows lacked an understanding of pathophysiology, treatment recommendations, and the ability to identify and treat critically ill patients. In the academic domain, respondents agreed that fellows were deficient in the areas of protocol design (54%, statistical analysis (54%, and manuscript writing (65%. These results suggest that general Ob/Gyn residency is ineffective in preparing fellows for advanced training in gynecologic oncology and should prompt a revision of the goals and objectives of resident education to correct these deficiencies.

  8. Discovering Massive Runaway Stars with Infrared Bow Shock Nebulae: Four OB Stars Found in WISE

    Science.gov (United States)

    Wernke, Heather N.; Kobulnicky, Henry A.; Dale, Daniel A.; Povich, Matthew S.; Andrews, Julian E.; Chick, William T.; Munari, Stephan; Olivier, Grace M.; Schurhammer, Danielle; Sorber, Rebecca L.

    2016-01-01

    Supernovae, pulsars, and gamma-ray bursts are examples of the result of the death of massive (late-O and early-B type) stars. Determining stellar mass loss rates can help us predict the type of death the star will endure. We focus on stars that are located at the center of an infrared bow shock nebula, indicating that the star was flung from its birthplace at supersonic speed. Observing these massive, high-velocity, runaway stars with bow shock nebulae to determine their spectral type will help in the measurements of their stellar mass loss rates. The spectra of four OB stars driving bow shock candidates are presented. These four candidates were found by searching through the Wide-field Infrared Survey Explorer (WISE) All-Sky Data Release and were the most visible in the WISE 21µm band. The spectrum for each star was obtained with the Longslit Spectrograph at the Wyoming Infrared Observatory (WIRO). The spectral types of G077.3617+01.16 (HD 229159), G079.8219+00.096 ([CPR2002]A10), G092.7265+00.18, and G076.0752-02.2044 (TYC 2697-1046-1) were found to be B1.0I, O9.0V, B0.0V, and B0.0V respectively. As predicted, the candidates are all either late-O or early-B type stars. Now that the spectral types of these stars are known, further analysis can be done to determine the velocities, temperatures, masses, and stellar mass loss rates.This work is supported by the National Science Foundation under grants AST-1063146 (REU), AST-1411851 (RUI), and AST-1412845.

  9. Fabrication and Characterization of AL-AL4C3 Nanocomposite by Mechanical Alloying

    Science.gov (United States)

    Mohammad Sharifi, E.; Enayati, M. H.; Karimzadeh, F.

    Aluminum carbide (Al4C3) seems to be an ideal reinforcement for producing aluminum matrix composites. Al4C3 has high hardness and shear strength as well as a high melting point. The dispersion of Al4C3 particles in the matrix produces a pinning effect that reduces aluminum grain growth, which improves the mechanical properties. In this study, aluminum powders were mixed with 4.5 wt.% graphite and mechanically alloyed using a high-energy ball mill in order to produce Al-Al4C3 nanocomposite. The structural evaluation of powder particles after different milling times was studied by X-ray diffractometry, scanning electron microscopy and microhardness measurements. The aluminum crystallite size estimated with broadening of XRD peaks by Williamson-Hall formula. XRD results suggested that the grain size of aluminum decreased to nanometer range (30 nm) during ball milling. No Al4C3 formed during the mechanical alloying process. Milled powders were then annealed at 300-600 °C for 1 h under argon atmosphere. Annealing at temperatures higher than 300 °C led to formation of Al4C3 phase which increased as annealing temperature increased. Aluminum grain size remained in nanometer range after annealing process. The microhardness of powder particles increased after annealing. Both effects are due to the formation of nanosized Al4C3 particles.

  10. Ocean Battlespace Sensing (OBS) S&T Department Annual Report

    Science.gov (United States)

    2014-09-30

    survey relative to a propagating background internal wave field. In the case of the Bay of Bengal, an energetic internal tide, apparently generated at the...Geophysical Union, 95(30), 269270. doi:10.1002/2014EO300001 6 Figure 4: Six days of along-drift variability in mixing and bio -optical quantities from the

  11. Synthesis and characterisation of substrate-based peptides as inhibitors of histone demethylase KDM4C

    DEFF Research Database (Denmark)

    Nielsen, Simon D; Leurs, Ulrike; Bergner, Magnus;

    2016-01-01

    The design and synthesis of modified pentapeptides based on a truncated version of the substrate for KDM4C, a histone lysine demethylase (KDM), and investigation of their inhibitory activity at KDM4C is reported. By modifying the lysine residue corresponding to lysine 9 at histone 3 (H3K9), three...... containing deprotected pentapeptide, thus demonstrating a highly facile and convergent synthetic strategy for making substrate-based inhibitors. One of the 14 peptides showed inhibitory activity at KDM4C demonstrating the need for an iron chelator in the pentapeptide series....

  12. Substrate- and Cofactor-independent Inhibition of Histone Demethylase KDM4C

    DEFF Research Database (Denmark)

    Leurs, Ulrike; Lohse, Brian; Rand, Kasper Dyrberg;

    2014-01-01

    sequence, or inhibit through substrate competition. Through screening of DNA-encoded peptide libraries against KDM1 and -4 histone demethylases by phage display, two cyclic peptides targeting the histone demethylase KDM4C were identified and developed as inhibitors by amino acid replacement, truncation...... and chemical modifications. Hydrogen/deuterium exchange mass spectrometry revealed that the peptide-based inhibitors target KDM4C through substrate-independent interactions located on the surface remote from the active site within less conserved regions of KDM4C. The sites discovered in this study provide...... a new approach of targeting KDM4C through substrate- and cofactor-independent interactions, and may be further explored to develop potent selective inhibitors and biological probes for the KDM4 family....

  13. w4CSeq: software and web application to analyze 4C-seq data.

    Science.gov (United States)

    Cai, Mingyang; Gao, Fan; Lu, Wange; Wang, Kai

    2016-11-01

    Circularized Chromosome Conformation Capture followed by deep sequencing (4C-Seq) is a powerful technique to identify genome-wide partners interacting with a pre-specified genomic locus. Here, we present a computational and statistical approach to analyze 4C-Seq data generated from both enzyme digestion and sonication fragmentation-based methods. We implemented a command line software tool and a web interface called w4CSeq, which takes in the raw 4C sequencing data (FASTQ files) as input, performs automated statistical analysis and presents results in a user-friendly manner. Besides providing users with the list of candidate interacting sites/regions, w4CSeq generates figures showing genome-wide distribution of interacting regions, and sketches the enrichment of key features such as TSSs, TTSs, CpG sites and DNA replication timing around 4C sites.

  14. Boron carbide (B{sub 4}C) coating. Deposition and testing

    Energy Technology Data Exchange (ETDEWEB)

    Azizov, E.; Barsuk, V. [Troitsk Institute for Innovation and Fusion Research (TRINITI), Moscow Region (Russian Federation); Begrambekov, L., E-mail: lbb@plasma.mephi.ru [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Buzhinsky, O. [Troitsk Institute for Innovation and Fusion Research (TRINITI), Moscow Region (Russian Federation); Evsin, A.; Gordeev, A.; Grunin, A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Klimov, N. [Troitsk Institute for Innovation and Fusion Research (TRINITI), Moscow Region (Russian Federation); Kurnaev, V. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation); Mazul, I. [Federal State Unitary Interprise Efremov Scientific Research Institute of Electrophysical Apparatus (NIIEFA Efremov), St-Peterburg (Russian Federation); Otroshchenko, V.; Putric, A. [Troitsk Institute for Innovation and Fusion Research (TRINITI), Moscow Region (Russian Federation); Sadovskiy, Ya.; Shigin, P.; Vergazov, S.; Zakharov, A. [National Research Nuclear University MEPhI (Moscow Engineering Physics Institute), Moscow (Russian Federation)

    2015-08-15

    Boron carbide was proposed as a material of in-situ protecting coating for tungsten tiles of ITER divertor. To prove this concept the project including investigation of regimes of plasma deposition of B{sub 4}C coating on tungsten and tests of boron carbide layer in ITER-like is started recently. The paper contends the first results of the project. The results of B{sub 4}C coating irradiation by the plasma pulses of QSPU-T plasma accelerator are presented. The new device capable of B{sub 4}C film deposition on tungsten and testing of the films and materials with ITER-like heat loads and ion- and electron irradiation is described. The results of B{sub 4}C coating deposition and testing of both tungsten substrate and coating are shown and discussed.

  15. Microstructure and Tensile Behaviour of B4C Reinforced ZA43 Alloy Composites

    Science.gov (United States)

    Adaveesh, B.; Halesh, G. M.; Nagaral, Madeva; Mohan Kumar, T. S.

    2016-09-01

    The work is carried out to investigate and study the mechanical properties of B4C reinforced ZA43 alloy metal matrix composites. In the present work ZA43 alloy is taken as the base matrix and B4C particulates as reinforcement material to prepare metal matrix composites by stir casting method. For metal matrix composites the reinforcement material was varied from 0 to 6 wt.% in steps of 3 wt.%. For each composite, the reinforcement particulates were preheated to a temperature of 300°C and dispersed into a vortex of molten ZA43 alloy. The microstructural characterization was done using scanning electron microscope. Mechanical properties like hardness, ultimate tensile strength and yield strength were evaluated as per ASTM standards. Further, scanning electron microphotographs revealed that there was uniform distribution of B4C particulates in ZA43 alloy matrix. Hardness, ultimate tensile strength and yield strength increased as wt.% of B4C increased in the base matrix.

  16. The Top 10 Things I LOVE about p4c Hawai'i

    Science.gov (United States)

    Ikeda, Jolyn

    2012-01-01

    In 2001, Dr. Thomas Jackson, or Dr. J as the author and her colleagues affectionately call him, spoke to the faculty at Waikiki Elementary. He described philosophy for children (p4c) Hawai'i and encouraged them to try P4C if something about it "resonated" with them. In the beginning, Dr. J held a p4t (philosophy for teachers)…

  17. TL and OSL studies of carbon doped magnesium aluminate (MgAl2O4:C)

    Science.gov (United States)

    Raj, Sanu S.; Mishra, D. R.; Soni, Anuj; Grover, V.; Polymeris, G. S.; Muthe, K. P.; Jha, S. K.; Tyagi, A. K.

    2016-10-01

    The MgAl2O4:C has been synthesized by using two different methods by electron gun and vacuum assisted melting of MgAl2O4 in presence of graphite. The MgAl2O4:C phosphor thus developed by these two different methods have similar types of the TL/OSL defects with multiple overlapping TL glow peaks from 100 °C to 400 °C. The Computerized Curve De-convolution Analysis (CCDA) has been used to measure TL parameters such as thermal trap depth, frequency factor and order of kinetic associated with charge transfer process in TL phenomenon. The investigated TL/OSL results show that these two methods of incorporating carbon in MgAl2O4 have generated closely resemble the defects of similar types in MgAl2O4:C lattice. However, the MgAl2O4:C synthesized by electron gun shows relatively larger concentration of the TL/OSL defects as compared to MgAl2O4:C synthesized using vacuum assisted melting method. The photo-ionization cross-section (PIC) associated with fastest OSL component of MgAl2O4: C is found to be ∼ 0.5 times than that of fastest OSL component of commercially available dosimetric grade α-Al2O3:C. The MgAl2O4:C thus developed shows good dynamic OSL dose linearity from few mGy to 1 Gy. This work reveals that MgAl2O4:C could be developed as potential tissue equivalent OSL / TL material.

  18. A multi-epoch XMM-Newton campaign on the core of the massive Cyg OB2 association

    CERN Document Server

    Rauw, Gregor

    2011-01-01

    Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have been conducted to more clearly understand this association. X-ray observations provide a powerful tool to overcome the effect of interstellar absorption and study the most energetic processes associated with the stars in Cyg OB2. We analyse XMM-Newton data to investigate the X-ray and UV properties of massive O-type stars as well as low-mass pre-main sequence stars in Cyg OB2. We obtained six XMM-Newton observations of the core of Cyg OB2. In our analysis, we pay particular attention to the variability of the X-ray bright OB stars, especially the luminous blue variable candidate Cyg OB2 #12. We find that X-ray variability is quite common among the stars in Cyg OB2. Whilst short-term variations are restricted mostly to low-mass pre-main sequence stars, one third of the OB stars display long-term variations. The X-ray fl...

  19. The superluminal radio source 4c 39. 25 as relativistic jet prototype. El cuasar superluminal 4C 93. 25 como prototipo de jet relativistia

    Energy Technology Data Exchange (ETDEWEB)

    Alberdi, A.; Gomez, J.L.; Marcaide, J.M.

    1993-01-01

    We have developed a numerical code which solves the synchrotron radiation transfer equations to compute the total and polarized emission of bent shocked relativistic jets, and we have applied it to reproduce the compact structure, kinematic evolution of the superluminal radio source 4C 39.25 contains a bent relativistic jet which is misaligned relative to the observer near the core region, leading to a relatively low core brightness. (Author) 12 refs.

  20. Simulation of a nuclear densimeter using the Monte Carlo MCNP-4C code; Simulacao de um densimetro nuclear utilizando o codigo Monte Carlo MCNP-4C

    Energy Technology Data Exchange (ETDEWEB)

    Penna, Rodrigo [UNI-BH, Belo Horizonte, MG (Brazil). Dept. de Ciencias Biologicas, Ambientais e da Saude (DCBAS/DCET); Silva, Clemente Jose Gusmao Carneiro da [Universidade Estadual de Santa Cruz, UESC, Ilheus, BA (Brazil); Gomes, Paulo Mauricio Costa [Universidade FUMEC, Belo Horizonte, MG (Brazil)

    2008-07-01

    Viability of building a nuclear wood densimeter based on low energy photons Compton scattering was done using Monte Carlo code (MCNP- 4C). It is simulated a collimated 60 keV beam of gamma rays emitted by {sup 241}Am source reaching wood blocks. Backscattered radiation by these blocks was calculated. Photons scattered were correlated with blocks of different wood densities. Results showed a linear relationship on wood density and scattered photons, therefore the viability of this wood densimeter. (author)

  1. Characterization of NCAM expression and function in BT4C and BT4Cn glioma cells

    DEFF Research Database (Denmark)

    1991-01-01

    The neural cell adhesion molecule, NCAM, plays an important role in cell-cell adhesion. Therefore, we have studied NCAM expression in the glioma cell lines BT4C and BT4Cn. We demonstrate that the 2 cell lines differ in their metastatic ability; while BT4C cells have a very low capacity...... for producing experimental metastases, that of BT4Cn cells is high. In BT4C cells NCAM is synthesized as 4 polypeptides with Mr's of 190,000, 140,000, 115,000 and 97,000. The 140,000, 115,000 and 97,000 polypeptides are glycosylated and for the 140,000 and 115,000 polypeptides sulfatation is observed......-substratum binding assay in which the binding of BT4C and BT4Cn cells to NCAM immobilized to glass was assessed. We found that BT4C cells adhere specifically to NCAM, and that adhesion is inhibited by anti-NCAM Fab'-fragments, while no specific binding of BT4Cn cells to NCAM was observed. The BT4C and BT4Cn cell...

  2. Jean-Pierre Poulain, Sociologie de l’obésité

    OpenAIRE

    Séguy, Laure

    2015-01-01

    L'ambition du présent ouvrage est de formuler la question de l'obésité du point de vue des sciences sociales. Il ne se réduit pas à la recherche de réponses à des hypothèses formulées par l'épidémiologie, mais se donne pour objectif de re-problématiser la question de l'obésité d'un point de vue sociologique et anthropologique. Les dimensions sociales de la question sont donc investies dans une triple perspective ; il s'agit pour Jean-Pierre Poulain de proposer une sociologie de l'obésité, une...

  3. ESTIMATION OF BURSTS LENGTH AND DESIGN OF A FIBER DELAY LINE BASED OBS ROUTER

    Directory of Open Access Journals (Sweden)

    RICHA AWASTHI

    2017-03-01

    Full Text Available The demand for higher bandwidth is increasing day by day and this ever growing demand cannot be catered to with current electronic technology. Thus new communication technology like optical communication needs to be used. In the similar context OBS (optical burst switching is considered as next generation data transfer technology. In OBS information is transmitted in forms of optical bursts of variable lengths. However, contention among the bursts is a major problem in OBS system, and for contention resolution defection routing is mostly preferred. However, deflection routing increases delay. In this paper, it is shown that the arrival of very large bursts is rare event, and for moderate burst length the buffering of contending burst can provide very effective solution. However, in case of arrival of large bursts deflection can be used.

  4. The performance study of oxide by-passed(OB) lateral double diffused MOSFET

    Science.gov (United States)

    Tang, Pan-pan

    2016-10-01

    An SOI LDMOS device structure with Oxide By-passed(OB) was investigated and its breakdown mechanism and characteristic of structure was analyzed. Its performance was verified by 3D numerical simulation with SILVACO TCAD software. The simulated results show that the electrical field element of the device is modulated by the concept of similar Superjunction(SJ) structure. Compared with the SJ LDMOS device, OB LDMOS obtains the same breakdown voltage, simultaneously the specific on-resistance of the OB LDMOS reduces from 3.81mΩ·cm2 to 1.96mΩ·cm2, except for achieving comparable performance and overcoming the high aspect ratio of fabrication structure and the difficulty of accurate concentration match of SJ LDMOS.

  5. Long-Acting PASylated Leptin Ameliorates Obesity by Promoting Satiety and Preventing Hypometabolism in Leptin-Deficient Lep(ob/ob) Mice.

    Science.gov (United States)

    Bolze, Florian; Morath, Volker; Bast, Andrea; Rink, Nadine; Schlapschy, Martin; Mocek, Sabine; Skerra, Arne; Klingenspor, Martin

    2016-01-01

    Body weight loss of Lep(ob/ob) mice in response to leptin is larger than expected from the reduction in energy intake alone, suggesting a thermogenic action of unknown magnitude. We exploited the superior pharmacological properties of a novel long-acting leptin prepared via PASylation to study the contribution of its anorexigenic and thermogenic effects. PASylation, the genetic fusion of leptin with a conformationally disordered polypeptide comprising 600 Pro/Ala/Ser (PAS) residues, provides a superior way to increase the hydrodynamic volume of the fusion protein, thus retarding kidney filtration and extending plasma half-life. Here a single PAS(600)-leptin injection (300 pmol/g) resulted in a maximal weight reduction of 21% 6 days after application. The negative energy balance of 300 kJ/(4 d) was driven by a decrease in energy intake, whereas energy expenditure remained stable. Mice that were food restricted to the same extent showed an energy deficit of only 220 kJ/(4 d) owing to recurring torpor bouts. Therefore, the anorexigenic effect of PAS(600)-leptin contributes 75% to weight loss, whereas the thermogenic action accounts for 25% by preventing hypometabolism. In a second experiment, just four injections of PAS(600)-leptin (100 pmol/g) administered in 5- to 6-day intervals rectified the Lep(ob/ob) phenotype. In total, 16 nmol of PAS(600)-leptin per mouse triggered a weight loss of 43% within 20 days and normalized hypothermia and glucose homeostasis as well as hepatic steatosis. The beneficial properties of PAS(600)-leptin are substantiated by a comparison with previous studies in which approximately 400 nmol (∼25-fold) unmodified leptin was mandatory to achieve similar improvements.

  6. NEAR INFRARED DIFFUSE INTERSTELLAR BANDS TOWARD THE CYGNUS OB2 ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Hamano, Satoshi; Kondo, Sohei; Sameshima, Hiroaki; Nakanishi, Kenshi; Kawakita, Hideyo [Laboratory of Infrared High-resolution Spectroscopy, Koyama Astronomical Observatory, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Kobayashi, Naoto [Institute of Astronomy, School of Science, University of Tokyo, 2-21-1 Osawa, Mitaka, Tokyo 181-0015 (Japan); Ikeda, Yuji [Photocoding, 460-102 Iwakura-Nakamachi, Sakyo-ku, Kyoto, 606-0025 (Japan); Yasui, Chikako; Mizumoto, Misaki; Matsunaga, Noriyuki; Fukue, Kei; Yamamoto, Ryo; Izumi, Natsuko [Department of Astronomy, Graduate School of Science, University of Tokyo, Bunkyo-ku, Tokyo 113-0033 (Japan); Mito, Hiroyuki [Kiso Observatory, Institute of Astronomy, School of Science, The University of Tokyo, 10762-30 Mitake, Kiso-machi, Kiso-gun, Nagano, 397-0101 (Japan); Nakaoka, Tetsuya; Kawanishi, Takafumi; Kitano, Ayaka; Otsubo, Shogo [Department of Physics, Faculty of Sciences, Kyoto Sangyo University, Motoyama, Kamigamo, Kita-ku, Kyoto 603-8555 (Japan); Kinoshita, Masaomi, E-mail: hamano@cc.kyoto-su.ac.jp [Solar-Terrestrial Environment Laboratory, Nagoya University, Furo-cho, Chikusa-ku, Nagoya, Aichi, 464-8601 (Japan)

    2016-04-10

    We obtained the near-infrared (NIR) high-resolution (R ≡ λ/Δλ ∼ 20,000) spectra of the seven brightest early-type stars in the Cygnus OB2 association for investigating the environmental dependence of diffuse interstellar bands (DIBs). The WINERED spectrograph mounted on the Araki 1.3 m telescope in Japan was used to collect data. All 20 of the known DIBs within the wavelength coverage of WINERED (0.91 < λ < 1.36 μm) were clearly detected along all lines of sight because of their high flux density in the NIR wavelength range and the large extinction. The equivalent widths (EWs) of DIBs were not correlated with the column densities of C{sub 2} molecules, which trace the patchy dense component, suggesting that the NIR DIB carriers are distributed mainly in the diffuse component. On the basis of the correlations among the NIR DIBs both for stars in Cyg OB2 and stars observed previously, λλ10780, 10792, 11797, 12623, and 13175 are found to constitute a “family,” in which the DIBs are correlated well over the wide EW range. In contrast, the EW of λ10504 is found to remain almost constant over the stars in Cyg OB2. The extinction estimated from the average EW of λ10504 (A{sub V} ∼ 3.6 mag) roughly corresponds to the lower limit of the extinction distribution of OB stars in Cyg OB2. This suggests that λ10504 is absorbed only by the foreground clouds, implying that the carrier of λ10504 is completely destroyed in Cyg OB2, probably by the strong UV radiation field. The different behaviors of the DIBs may be caused by different properties of the DIB carriers.

  7. Reconstruction of Ob River, Russia, discharge from ring widths of floodplain trees

    Science.gov (United States)

    Agafonov, Leonid I.; Meko, David M.; Panyushkina, Irina P.

    2016-12-01

    The Ob is the third largest Eurasian river supplying heat and freshwater to the Arctic Ocean. These inputs influence water salinity, ice coverage, ocean temperatures and ocean circulation, and ultimately the global climate system. Variability of Ob River flow on long time scales is poorly understood, however, because gaged flow records are short. Eleven tree-ring width chronologies of Pinus sibirica and Larix sibirica are developed from the floodplain of the Lower Ob River, analyzed for hydroclimatic signal and applied as predictors in a regression model to reconstruct 8-month average (December-July) discharge of the Ob River at Salekhard over the interval 1705-2012 (308 yrs). Correlation analysis suggests the signal for discharge comes through air temperature: high discharge and floodplain water levels favor cool growing-season air temperature, which limits tree growth for the sampled species at these high latitudes. The reconstruction model (R2 = 0.31, 1937-2009 calibration period) is strongly supported by cross-validation and analysis of residuals. Correlation of observed with reconstructed discharge improves with smoothing. The long-term reconstruction correlates significantly with a previous Ob River reconstruction from ring widths of trees outside the Ob River floodplain and extends that record by another century. Results suggest that large multi-decadal swings in discharge have occurred at irregular intervals, that variations in the 20th and 21st centuries have been within the envelope of natural variability of the past 3 centuries, and that discharge data for 1937-2009 underestimate both the variability and persistence of discharge in the last 3 centuries. The reconstruction gives ecologists, climatologists and water resource planners a long-term context for assessment of climate change impacts.

  8. Analyzing the Effects of Nitrogen Deficiency on the PHB Production of Methylosinus trichosporium OB3b

    Science.gov (United States)

    Kyauk, E.

    2011-12-01

    Polyhydroxybutyrate (PHB) is a biodegradable thermoplastic that is produced by various microorganisms. Because of its potential to replace conventional plastics, it has been closely researched in the past few years. Methanotrophic bacteria, bacteria that consume methane, produce this bioplastic when it lacks certain nutrients. The utilization of methane to produce PHB shows much promise as methane is a cheap, plentiful gas. In this study, we observed the methanotroph, Methylosinus trichosporium OB3b , and its yield of PHB in the absence of nitrogen. The optical density of Methylosinus trichosporium OB3b was measured in order to observe cell growth and PHB production patterns over a 48 hour period.

  9. Nov način simuliranja občutka vožnje

    OpenAIRE

    ZAJC, MATIC

    2015-01-01

    To diplomsko delo predstavlja nov način simuliranja občutka vožnje. V ta namen na trgu obstajajo različni simulatorji. Tem je skupno, da za generiranje sile uporabljajo gravitacijo, kar za seboj prinese številne omejitve, predvsem pri simuliranju dolgotrajnih pospeškov. Naš način simuliranja občutka vožnje pa deluje na principu generiranje sile na glavo uporabnika s pomočjo aktuatorjev. V prvem delu si bomo na kratko ogledali zgodovino razvoja simulatorjev. Simulatorji so bili v zadnjih de...

  10. 促红细胞生成素改善ob/ob小鼠肝脏脂质沉积%Protective effects of erythropoietin on lipid metabolism in the liver of ob/ob mice

    Institute of Scientific and Technical Information of China (English)

    洪汀; 毕艳; 葛智娟; 汤孙寅焱; 汤文娟; 朱大龙

    2016-01-01

    目的:研究促红细胞生成素(EPO)对肝脏脂质沉积的影响及可能的分子机制。方法12只雄性8周龄遗传型肥胖小鼠(ob/ob)随机数字表法分为2组:一组腹腔注射EPO(3000 U/kg),即EPO组(ob/ob+EPO,n=6);另一组注射等量磷酸盐缓冲液(PBS),即PBS组(ob/ob+PBS,n=6);同窝野生型C57BL/6小鼠作为正常对照组(C57BL/6,n=6),药物干预5周。以棕榈酸(PA,0.5 mmol/L)及不同浓度EPO处理人肝癌细胞株HepG2,分为对照组(不处理)、PA组、PA+EPO (5 U/ml)组及PA+EPO (10 U/ml)组。油红O染色观察各组小鼠肝组织及HepG2细胞内脂质沉积。Western blotting法检测各组小鼠肝脏及HepG2细胞中EPO受体(EPOR)、固醇调节元件结合蛋白1c(SREBP-1c)、脂肪酸合酶(FAS)、乙酰辅酶A羧化酶(ACC)及肉毒碱棕榈酰基转移酶1a(CPT-1a)的蛋白表达。多组间数据比较采用单因素方差分析,两两比较采用最小显著差异法。结果油红O染色显示EPO干预的小鼠肝脏组织及HepG2细胞内脂质沉积均较各自对照组减少。与PBS组相比,EPO组小鼠肝脏SREBP-1c、FAS、ACC蛋白水平显著下降(分别为0.78±0.08比1.23±0.03、1.03±0.08比1.16±0.01、1.10±0.33比1.69±0.02,t=-6.906、-2.756、-8.794,均P<0.05),EPOR和CPT-1a蛋白水平明显升高(分别为1.28±0.14比0.97±0.06、0.77±0.06比0.60±0.12,t=2.749、2.655,均P<0.05)。在HepG2细胞中,与PA组相比,PA+EPO(10 U/ml)组中SREBP-1c、FAS、ACC蛋白水平显著下降(t=-10.731、-2.760、-9.618,均P<0.05), EPOR和CPT-1a蛋白水平升高(t=7.556、2.674,均P<0.05)。结论 EPO可能通过抑制肝脏脂质合成,促进脂肪酸氧化,从而减少肝脏脂质过度沉积。%Objective To investigate the effects of erythropoietin (EPO) on hepatic lipid metabolism and explore the underlying mechanism. Methods Twelve eight-week female ob/ob mice were randomly divided

  11. Al4C3 Hydration Thermochemical Analysis for Burned Carbon-containing Refractories with Al

    Institute of Scientific and Technical Information of China (English)

    YANG Ding'ao; YU Zhiming; FAN Liuwu

    2003-01-01

    In this paper, X-ray diffractogram analysis and SEM observation of Al4 C3 formed at high temperature from carbon-containing refractories with Al have been carried out.Aluminum added to carbon-containing refractories reacts with C(s)to form Al4 C3(s) gradually during heating from 600 ℃ to 1200℃.It is considered that the interlocked structure of Al4 C3 plate crystals promotes the outstanding increase of hot modulus of rupture of carbon-containing refractories with Al. The HMOR of carbon-containing refractories added with Al additive from 0 to 5wt% increases by 2.8 times being from 6.5MPa to 18.2MPa.After a thermochemical calculation for hydration reaction processes of Al4 C3 and H2O(g), the equilibrium partial pressure chart of H2O(g)in H2O-Al4C3-Al(OH)3 system vs various temperatures has been attained . The H2O (g) partial pressure in the air needed for the Al4 C3 hydration reaction is no more than 10~18 atm at the temperature below 120℃.It is considered that the burned carbon-containing refractories with Al is extremely easy to hydrate and the cracking of burned carbon-containing refractories is generated because that the hydration expansion is 2.11 times during transforming from Al4 C3 to Al(OH)3.The fundamental measure against hydration of the refractories is to insulate the refractories from H2O(g)by various means such as pitch impregnation or other sealing materials.

  12. Advective transport observations with MODPATH-OBS--documentation of the MODPATH observation process

    Science.gov (United States)

    Hanson, R.T.; Kauffman, L.K.; Hill, M.C.; Dickinson, J.E.; Mehl, S.W.

    2013-01-01

    The MODPATH-OBS computer program described in this report is designed to calculate simulated equivalents for observations related to advective groundwater transport that can be represented in a quantitative way by using simulated particle-tracking data. The simulated equivalents supported by MODPATH-OBS are (1) distance from a source location at a defined time, or proximity to an observed location; (2) time of travel from an initial location to defined locations, areas, or volumes of the simulated system; (3) concentrations used to simulate groundwater age; and (4) percentages of water derived from contributing source areas. Although particle tracking only simulates the advective component of conservative transport, effects of non-conservative processes such as retardation can be approximated through manipulation of the effective-porosity value used to calculate velocity based on the properties of selected conservative tracers. This program can also account for simple decay or production, but it cannot account for diffusion. Dispersion can be represented through direct simulation of subsurface heterogeneity and the use of many particles. MODPATH-OBS acts as a postprocessor to MODPATH, so that the sequence of model runs generally required is MODFLOW, MODPATH, and MODPATH-OBS. The version of MODFLOW and MODPATH that support the version of MODPATH-OBS presented in this report are MODFLOW-2005 or MODFLOW-LGR, and MODPATH-LGR. MODFLOW-LGR is derived from MODFLOW-2005, MODPATH 5, and MODPATH 6 and supports local grid refinement. MODPATH-LGR is derived from MODPATH 5. It supports the forward and backward tracking of particles through locally refined grids and provides the output needed for MODPATH_OBS. For a single grid and no observations, MODPATH-LGR results are equivalent to MODPATH 5. MODPATH-LGR and MODPATH-OBS simulations can use nearly all of the capabilities of MODFLOW-2005 and MODFLOW-LGR; for example, simulations may be steady-state, transient, or a combination

  13. Cytolipotoxicity-induced involution of the female reproductive tract following expression of obese (ob/ob) and diabetes (db/db) genotype mutations: progressive, hyperlipidemic transformation into adipocytic tissues.

    Science.gov (United States)

    Garris, David R; Garris, Bryan L

    2004-01-01

    Both diabetes (db/db) and obese (ob/ob) single gene mutations induce a progressive, hyperglycemic-hyperinsulinemic endometabolic environment which promotes hypercytolipidemic, utero-ovarian involution in C57BL/KsJ mice. The progressive expression of the induced diabetes-obesity syndrome (DOS) results in female reproductive sterility and eventual organoatrophy. In order to define the intra-cytoplasmic alterations induced by the progressive cytolipidemia on cellular vitality, utero-ovarian tissue samples were collected from both control (+/?) and littermate-matched ob/ob or db/db C57BL/KsJ mice at either 4 weeks (initial-onset DOS phase), 8 weeks (progressive, overt DOS phase), or 16 weeks (chronic-DOS phase) of age for cytolipid distribution analysis. All db/db and ob/ob mutant groups exhibited phenotypic obesity and systemic hyperglycemia-hyperinsulinemia relative to age-matched littermate +/? groups. In all db/db and ob/ob age groups, a progressive hypercytolipidemia was noted relative to +/? groups. When analyzed for lipid channeling, a progressive perinuclear mapping pattern of cytolipid distribution was noted. The primary locus of initial db/db and ob/ob cytolipid deposition was localized to the baso-polar regions in endometrial epithelia samples, or to the interstitium-thecal layer border of ovarian follicular compartments, during the initial-onset DOS phase. Progressively, intra-cytoplasmic lipid mobilization promoted a consistent perinuclear channeling of lipid vacuoles, ultimately isolating nuclear loci from the peripherally displaced cytoplasmic organelles within uterine epithelial layers. In db/db and ob/ob ovarian tissue samples, a progressive, gradient-related lipid infiltration of interstitial, thecal and, ultimately, granulosa cell layers promoted an enhanced rate of follicular-lipidemic atresia relative to +/? groups. In each tissue layer, the cytolipidemia promoted a dramatic perinuclear lipid-isolation barrier from intra-cytoplasmic organelle

  14. Homologous Transcription Factors DUX4 and DUX4c Associate with Cytoplasmic Proteins during Muscle Differentiation.

    Directory of Open Access Journals (Sweden)

    Eugénie Ansseau

    Full Text Available Hundreds of double homeobox (DUX genes map within 3.3-kb repeated elements dispersed in the human genome and encode DNA-binding proteins. Among these, we identified DUX4, a potent transcription factor that causes facioscapulohumeral muscular dystrophy (FSHD. In the present study, we performed yeast two-hybrid screens and protein co-purifications with HaloTag-DUX fusions or GST-DUX4 pull-down to identify protein partners of DUX4, DUX4c (which is identical to DUX4 except for the end of the carboxyl terminal domain and DUX1 (which is limited to the double homeodomain. Unexpectedly, we identified and validated (by co-immunoprecipitation, GST pull-down, co-immunofluorescence and in situ Proximal Ligation Assay the interaction of DUX4, DUX4c and DUX1 with type III intermediate filament protein desmin in the cytoplasm and at the nuclear periphery. Desmin filaments link adjacent sarcomere at the Z-discs, connect them to sarcolemma proteins and interact with mitochondria. These intermediate filament also contact the nuclear lamina and contribute to positioning of the nuclei. Another Z-disc protein, LMCD1 that contains a LIM domain was also validated as a DUX4 partner. The functionality of DUX4 or DUX4c interactions with cytoplasmic proteins is underscored by the cytoplasmic detection of DUX4/DUX4c upon myoblast fusion. In addition, we identified and validated (by co-immunoprecipitation, co-immunofluorescence and in situ Proximal Ligation Assay as DUX4/4c partners several RNA-binding proteins such as C1QBP, SRSF9, RBM3, FUS/TLS and SFPQ that are involved in mRNA splicing and translation. FUS and SFPQ are nuclear proteins, however their cytoplasmic translocation was reported in neuronal cells where they associated with ribonucleoparticles (RNPs. Several other validated or identified DUX4/DUX4c partners are also contained in mRNP granules, and the co-localizations with cytoplasmic DAPI-positive spots is in keeping with such an association. Large muscle RNPs

  15. Mitochondrial haplogroup C4c: a rare lineage entering America through the ice-free corridor?

    Science.gov (United States)

    Hooshiar Kashani, Baharak; Perego, Ugo A; Olivieri, Anna; Angerhofer, Norman; Gandini, Francesca; Carossa, Valeria; Lancioni, Hovirag; Semino, Ornella; Woodward, Scott R; Achilli, Alessandro; Torroni, Antonio

    2012-01-01

    Recent analyses of mitochondrial genomes from Native Americans have brought the overall number of recognized maternal founding lineages from just four to a current count of 15. However, because of their relative low frequency, almost nothing is known for some of these lineages. This leaves a considerable void in understanding the events that led to the colonization of the Americas following the Last Glacial Maximum (LGM). In this study, we identified and completely sequenced 14 mitochondrial DNAs belonging to one extremely rare Native American lineage known as haplogroup C4c. Its age and geographical distribution raise the possibility that C4c marked the Paleo-Indian group(s) that entered North America from Beringia through the ice-free corridor between the Laurentide and Cordilleran ice sheets. The similarities in ages andgeographical distributions for C4c and the previously analyzed X2a lineage provide support to the scenario of a dual origin for Paleo-Indians. Taking into account that C4c is deeply rooted in the Asian portion of the mtDNA phylogeny and is indubitably of Asian origin, the finding that C4c and X2a are characterized by parallel genetic histories definitively dismisses the controversial hypothesis of an Atlantic glacial entry route into North America.

  16. Wetting of B{sub 4}C, TiC and graphite substrates by molten Mg

    Energy Technology Data Exchange (ETDEWEB)

    Zhang Dan [Key Laboratory of Automobile Materials, Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Shen Ping, E-mail: shenping@jlu.edu.cn [Key Laboratory of Automobile Materials, Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China); Shi Laixin; Jiang Qichuan [Key Laboratory of Automobile Materials, Department of Materials Science and Engineering, Jilin University, No. 5988 Renmin Street, Changchun 130025 (China)

    2011-10-17

    Highlights: {yields} The wettability of TiC, B4C and C by molten Mg was determined using an improved sessile drop method. {yields} A new method to evaluate the wetting behavior coupled with evaporation and reaction was proposed. {yields} The bonding characteristics in the Mg/B4C, Mg/TiC and Mg/graphite systems were evaluated. - Abstract: The isotherm wetting of B{sub 4}C, TiC and graphite substrates by molten Mg was studied in a flowing Ar atmosphere at 973-1173 K using an improved sessile drop method. The initial contact angles are in the ranges of 95-87 deg., 74-60 deg. and 142-124 deg., respectively, moderately depending on the temperature. All the systems are non-reactive in nature; however, the presence of impurity of free boron at the B{sub 4}C surface gave rise to the chemical reaction with molten Mg and thus promoted the wettability to a certain degree. A new method was proposed to evaluate the wetting behavior coupled with evaporation and chemical reaction. Furthermore, based on the comparison of the work of adhesion and cohesion, the bonding in the Mg/B{sub 4}C and Mg/TiC systems is presumably mainly chemical while that in the Mg/graphite system is physical.

  17. WSRT 1.4 and 5-GHz light curves for WR 147 (AS 431, WN8(h)+OB)

    NARCIS (Netherlands)

    Gunawan, DYAS; de Bruyn, AG; van der Hucht, KA; Williams, PM

    2001-01-01

    The results of more than 8-yr monitoring (1988-1997) of the Wolf-Rayet binary WR 147 (WN8(h)-OB) with the Westerbork Synthesis Radio Telescope (WSRT) are presented. When the strong winds of the Wolf-Rayet (WR) and OB binary components collide. they produce non-thermal excess radiation in the region

  18. The protoplanetary disks in the nearby massive star forming region Cygnus OB2

    CERN Document Server

    Guarcello, M G; Wright, N J; Drew, J E; Gutermuth, R A; Hora, J L; Naylor, T; Aldcroft, T; Fruscione, A; Garcia-Alvarez, D; Kashyap, V L; King, R

    2013-01-01

    The formation of stars in massive clusters is one of the main modes of the star formation process. However, the study of massive star forming regions is hampered by their typically large distances to the Sun. One exception to this is the massive star forming region Cygnus OB2 in the Cygnus X region, at the distance of about 1400 pc. Cygnus OB2 hosts very rich populations of massive and low-mass stars, being the best target in our Galaxy to study the formation of stars, circumstellar disks, and planets in presence of massive stars. In this paper we combine a wide and deep set of photometric data, from the r band to 24 micron, in order to select the disk bearing population of stars in Cygnus OB2 and identify the class I, class II, and stars with transition and pre-transition disks. We selected 1843 sources with infrared excesses in an area of 1 degree x 1 degree centered on Cyg OB2 in several evolutionary stages: 8.4% class I, 13.1% flat-spectrum sources, 72.9% class II, 2.3% pre-transition disks, and 3.3% tran...

  19. OB Associations, Wolf-Rayet Stars, and the Origin of Galactic Cosmic Rays

    CERN Document Server

    Binns, W R; Arnould, M; Cummings, A C; De Nolfo, G A; Goriely, S; Israel, M H; Leske, R A; Mewaldt, R A; Meynet, G; Scott, L M; Stone, E C; Von Rosenvinge, T T

    2007-01-01

    We have measured the isotopic abundances of neon and a number of other species in the galactic cosmic rays (GCRs) using the Cosmic Ray Isotope Spectrometer (CRIS) aboard the ACE spacecraft. Our data are compared to recent results from two-component Wolf-Rayet (WR) models. The three largest deviations of galactic cosmic ray isotope ratios from solar-system ratios predicted by these models, 12C/16O, 22Ne/20Ne, and 58Fe/56Fe, are very close to those observed. All of the isotopic ratios that we have measured are consistent with a GCR source consisting of ~20% of WR material mixed with ~80% material with solar-system composition. Since WR stars are evolutionary products of OB stars, and most OB stars exist in OB associations that form superbubbles, the good agreement of our data with WR models suggests that OB associations within superbubbles are the likely source of at least a substantial fraction of GCRs. In previous work it has been shown that the primary 59Ni (which decays only by electron-capture) in GCRs has...

  20. ObsPack: a framework for the preparation, delivery, and attribution of atmospheric greenhouse gas data

    NARCIS (Netherlands)

    Masarie, K. A.; Peters, W.; Jacobson, A. R.; Tans, P. P.

    2014-01-01

    Observation Package (ObsPack) is a framework designed to bring together atmospheric greenhouse gas observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. Data products creat

  1. ObsPack: a framework for the preparation, delivery, and attribution of atmospheric greenhouse gas measurements

    NARCIS (Netherlands)

    Masarie, K. A.; Peters, W.; Jacobson, A. R.; Tans, P. P.

    2014-01-01

    Observation Package (ObsPack) is a framework designed to bring together atmospheric greenhouse gas observations from a variety of sampling platforms, prepare them with specific applications in mind, and package and distribute them in a self-consistent and well-documented product. Data products creat

  2. The Galaxy Kinematics from OB Stars with Proper Motions from the Gaia DR1 Catalog

    CERN Document Server

    Bobylev, V V

    2016-01-01

    We consider two previously studied samples of OB stars with different distance scales. The first one consists of 98 massive spectroscopic binary stars with photometric distances, and the second one consists on 140 OB stars with the distances determined along the lines of interstellar calcium. The OB stars are located at distances up to 7 kpc from the Sun. They are identified with the Gaia DR1 catalog. It is shown that the use of the proper motions, taken from the Gaia DR1 catalog, allows to reduce random errors of determination of the Galactic rotation parameters in comparison with the previously known ones. From the analysis of 208 OB stars from the Gaia DR1 catalog with proper motions and parallaxes with relative errors less than 200% we found the Galactic kinematic parameters. In addition the Galactic rotation parameters were obtained from only line-of-sight velocities of the same stars. From the comparison of the two values of \\Omega^{'}_0 a distance scale of the Gaia DR1 catalog was determined as a value...

  3. Spin Evolution of Neutron Stars in OB/X-ray Binaries

    Institute of Scientific and Technical Information of China (English)

    Fan Zhang; Xiang-Dong Li; Zhen-Ru Wang

    2004-01-01

    We have investigated the relation between the orbital period Porb and the spin period Ps of neutron stars in OB/X-ray binaries.By simulating the timedevelopment of the mass loss rate and radius expansion of a 20M(◎)donor star,we have calculated the detailed spin evolution of the neutron star before steady wind accretion occurs(that is,when the break spin period is reached),or when the OB star begins evolving off the main sequence or has filled its Roche lobe.Our results are compatible with the observations of OB/X-ray binaries.We find that in relatively narrow systems with orbital periods less than tens of days,neutron stars with initial magnetic field B0 stronger than about 3 × 1012 G can reach the break spin period to allow steady wind accretion in the main sequence time,whereas neutron stars with B0 < 3 × 1012 G and/or in wide systems would still be in one of the pulsar,rapid rotator or propeller phases when the companion evolves off the main sequence or fills its Roche lobe.Our results may help understand the various characteristics of the observed OB/neutron star binaries along with their distributions in the Ps -Porb diagram.

  4. Kinetics of Chlorinated Hydrocarbon Degradation by Methylosinus trichosporium OB3b and Toxicity of Trichloroethylene

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Oedzes, Johannes Y.; Waarde, Jacob J. van der; Janssen, Dick B.

    1991-01-01

    The kinetics of the degradation of trichloroethylene (TCE) and seven other chlorinated aliphatic hydrocarbons by Methylosinus trichosporium OB3b were studied. All experiments were performed with cells grown under copper stress and thus expressing soluble methane monooxygenase. Compounds that were re

  5. Degradation of Chlorinated Aliphatic Hydrocarbons by Methylosinus trichosporium OB3b Expressing Soluble Methane Monooxygenase

    NARCIS (Netherlands)

    Oldenhuis, Roelof; Vink, Ruud L.J.M.; Janssen, Dick B.; Witholt, Bernard

    1989-01-01

    Degradation of trichloroethylene (TCE) by the methanotrophic bacterium Methylosinus trichosporium OB3b was studied by using cells grown in continuous culture. TCE degradation was a strictly cometabolic process, requiring the presence of a cosubstrate, preferably formate, and oxygen. M. trichosporium

  6. High-mass X-ray binaries and OB runaway stars

    NARCIS (Netherlands)

    Kaper, L.; van der Meer, A.; Tijani, A.H.; Allen, C.; Scarfe, C.

    2004-01-01

    High-mass X-ray binaries (HMXBs) represent an important phase in the evolution of massive binary systems and provide fundamental information on the properties of the OB-star primaries and their compact secondaries (neutron star, black hole). Recent observations indicate that the neutron stars in som

  7. Hot pressing of B{sub 4}C/SiC composites

    Energy Technology Data Exchange (ETDEWEB)

    Sahin, F.C.; Turhan, E.; Yesilcubuk, S.A.; Addemir, O. [Ystanbul Technical University, Faculty of Chemistry and Metallurgy, Materials and Metallurgical Engineering Dept., Maslak-Ystanbul (Turkey)

    2005-07-01

    B{sub 4}C/SiC ceramic composites containing 10-20-30 vol % SiC were prepared by hot pressing method. The effect of SiC addition and hot pressing temperature on sintering behaviour and mechanical properties of hot pressed composites were investigated. Microstructures of hot pressed samples were examined by SEM technique. Three different temperatures (2100 deg. C, 2200 deg. C and 2250 deg. C) were used to optimize hot pressing temperature applying 100 MPa pressure under argon atmosphere during the sintering procedure. The highest relative density of 98.44 % was obtained by hot pressing at 2250 deg. C. However, bending strengths of B{sub 4}C/SiC composite samples were lower than monolithic B{sub 4}C in all experimental conditions. (authors)

  8. Neutron absorption of Al-Si-Mg-B{sub 4}C composite

    Energy Technology Data Exchange (ETDEWEB)

    Abdullah, Yusof, E-mail: yusofabd@nuclearmalaysia.gov.my; Yusof, Mohd Reusmaazran [Malaysian Nuclear Agency, 43000, Bangi Selangor (Malaysia); Ibrahim, Anis Syukriah; Daud, Abdul Razak [Department of Applied Physics, Faculty of Science & Technology, National University of Malaysia, 43600, Bangi Selangor (Malaysia)

    2016-01-22

    Al-Si-Mg-B{sub 4}C composites containing 2-8 wt% of B{sub 4}C were prepared by stir casting technique. Homogenization treatment was carried out at temperatures of 540°C for 4 houra and followed by ageing at 180°C for 2 houra. Microstructure and phase identification were studied by scanning electron microscopy (SEM) and X-ray diffraction (XRD) respectively. Neutron absorption study was investigated using neutron source Am/Be{sup 241}. The result indicated that higher B{sub 4}C content improved the neutron absorption property. Meanwhile homogeneity of the composite was increased by ageing processes. This composite is potential to be used as neutron shielding material especially for nuclear reactor application.

  9. In situ carbon coated LiFePO4/C microrods with improved lithium intercalation behavior.

    Science.gov (United States)

    Bhuvaneswari, D; Kalaiselvi, N

    2014-01-28

    LiFePO4/C microrods consisting of building blocks of interconnected nanoparticles surrounded by a thin and amorphous coating of carbon have been prepared by a customized hydrothermal method. Appreciable discharge capacity values of 168 mA h g(-1) at 0.1 C and 130 mA h g(-1) at 5 C rates have been exhibited by the currently synthesized LiFePO4/C cathode. The study enumerates the feasibility of exploiting the hydrothermal method to prepare an in situ carbon coated LiFePO4/C compound with tunable morphological properties and desirable electrochemical properties observed for up to 100 cycles at a 5 C rate.

  10. Epidémie d’obésité : comment lutter

    Directory of Open Access Journals (Sweden)

    Poulain Jean‐Pierre

    2003-03-01

    Full Text Available L’obésité peut être l’objet d’un double regard sociologique. Le premier, adoptant la posture de recherche empiriste, positiviste et déterministe de l’épidémiologie médicale, accepte l’idée que l’obésité est un problème de santé publique et prend en charge l’identification des dimensions sociales associées à cette morbidité. Il s’intéresse à la distribution sociale de l’obésité, repère le rôle de la stigmatisation des obèses dans les sociétés développées. Il s’attache à identifier les fonctions de l’alimentation dans la transition épidémiologique et cherche à comprendre l’impact de la modernité alimentaire sur le développement de cette pathologie. Mais le regard sociologique peut aussi prendre l’obésité comme une construction sociale. Il met alors l’accent sur le relativisme historique et culturel des représentations qui s’agrégent sur cet état. Il cherche à décrire l’émergence, la diffusion et l’acceptation de l’idée que l’obésité est un problème de santé publique. Il montre comment la médicalisation de l’obésité déborde aujourd’hui sur l’alimentation en général et déconstruit les hypothèses implicites des campagnes nutritionnelles de prévention. De cette confrontation, un champ de recherche nouveau émerge, à l’interface des sciences de la nutrition et de la socio‐anthropologie de l’alimentation, dont l’objet est de mettre au jour la complexité des décisions alimentaires

  11. Purification and characterization of oligonucleotide binding (OB)-fold protein from medicinal plant Tinospora cordifolia.

    Science.gov (United States)

    Amir, Mohd; Haque, Md Anzarul; Wahiduzzaman; Dar, Mohammad Aasif; Islam, Asimul; Ahmad, Faizan; Hassan, Md Imtaiyaz

    2016-01-01

    The oligonucleotide binding fold (OB-fold) is a small structural motif present in many proteins. It is originally named for its oligonucleotide or oligosaccharide binding properties. These proteins have been identified as essential for replication, recombination and repair of DNA. We have successfully purified a protein contains OB-fold from the stem of Tinospora cordifolia, a medicinal plants of north India. Stems were crushed and centrifuged, and fraction obtained at 60% ammonium sulphate was extensively dialyzed and applied to the weak anion exchange chromatography on Hi-Trap DEAE-FF in 50mM Tris-HCl buffer at pH 8.0. Eluted fractions were concentrated and applied to gel filtration column to get pure protein. We observed a single band of 20-kDa on SDS-PAGE. Finally, the protein was identified as OB-fold by MALDI-TOF. The purified OB-fold protein was characterized for its secondary structural elements using circular dichroism (CD) in the far-UV region. Generally the OB-fold has a characteristic feature as five-stranded beta-sheet coiled to form a closed beta- barrel. To estimate its chemical stability, guanidinium chloride-induced denaturation curve was followed by observing changes in the far-UV CD as a function of the denaturant concentration. Analysis of this denaturation curve gave values of 8.90±0.25kcalmol(-1) and 3.78±0.18M for ΔGD° (Gibbs free energy change at 25°C) and Cm (midpoint of denaturation), respectively. To determine heat stability parameters of OB-fold protein, differential scanning calorimetry was performed. Calorimetric values of ΔGD°, Tm (midpoint of denaturation), ΔHm (enthalpy change at Tm), and ΔCp (constant-pressure heat capacity change) are 9.05±0.27kcalmol(-1), 85.2±0,3°C, 105±4kcalmol(-1) and 1.6±0.08kcalmol(-1)K(-1). This is the first report on the isolation, purification and characterization of OB-fold protein from a medicinal plant T. cordifolia.

  12. Synthesis and characterisation of substrate-based peptides as inhibitors of histone demethylase KDM4C

    DEFF Research Database (Denmark)

    Nielsen, Simon D; Leurs, Ulrike; Bergner, Magnus;

    2016-01-01

    The design and synthesis of modified pentapeptides based on a truncated version of the substrate for KDM4C, a histone lysine demethylase (KDM), and investigation of their inhibitory activity at KDM4C is reported. By modifying the lysine residue corresponding to lysine 9 at histone 3 (H3K9), three...... different series of peptides were designed and synthesized. One series contained N-acylated H3K9 and two series introduced triazoles in this position via click chemistry to enable facile variation of headgroups. As the click reaction is compatible with free amino acids this was performed on an azido...

  13. Formation of a 4c tetraquark in J/{psi}-meson pair production at LHC

    Energy Technology Data Exchange (ETDEWEB)

    Berezhnoy, A. V., E-mail: Alexander.Berezhnoy@cern.ch [Moscow State University, Skobeltsyn Institute of Nuclear Physics (Russian Federation); Likhoded, A. K., E-mail: Anatolii.Likhoded@ihep.ru; Luchinsky, A. V., E-mail: Alexey.Luchinsky@ihep.ru; Novoselov, A. A., E-mail: Alexey.Novoselov@cern.ch [Institute for High Energy Physics (Russian Federation)

    2012-08-15

    Cross sections for J{psi}-meson pair production in proton-proton interaction at the c.m. collision energy of {radical}a = 7 TeV were theoretically predicted under conditions of various kinematical cuts. The possible contribution to this process from the decays of 4c tetraquarks, new hypothetic particles consisting of two valence c quarks and two valence c-bar antiquarks, was studied. It is shown that at least one such state (tensor 4c tetraquark) can in principle be observed experimentally under conditions of the LNCb experiment.

  14. RECENT INTERVIEWS WITH PHILOSOPHY FOR CHILDREN (P4C) SCHOLARS AND PRACTITIONERS

    OpenAIRE

    naji, saeed

    2013-01-01

    In these two long-distance interviews, Iranian Saeed Naji, founder of the Philosophy for Children (P4C) movement in Iran, questions two veteran practitioners of philosophy for children/community of philosophical inquiry (CPI). He raises issues related to P4C/CPI as representative of a larger educational paradigm, which he calls “reflective education,” and weighs its prospects for replacing what he calls the “traditional paradigm” worldwide. He also queries the two scholars on i...

  15. sup 1 sup 4 C dating of the Niya site in the Tarim Basin

    CERN Document Server

    Yonenobu, H

    2000-01-01

    The sup 1 sup 4 C ages were determined for wood samples collected from the Niya site in the Tarim Basin, China. The calendar sup 1 sup 4 C ages are the oldest in the northern part (800-100 cal BC) and the youngest (140-620 cal AD) in the southern part. The results suggest that ancient Niya had moved southward during the period of ca. 2300-1600 BP. The ages in the middle and the southern parts are consistent with the previous studies of old documents.

  16. Synthesis, Characterization and Properties of LiFePO4/C Cathode Material

    Institute of Scientific and Technical Information of China (English)

    ZHOU Xin-wen; ZHAN Dan; WANG Li-na; LIU Qiao-yun; ZONG Hong-xing; ZHANG Ke-li

    2005-01-01

    Lithium iron phosphate coated with carbon(LiFePO4/C) was synthesized by improved solid-state reaction using comparatively lower temperature and fewer sintering time. The carbon came from citric acid, which acted as a new carbon source. It was characterized by thermogravimetry and differential thermal analysis (TG/DTA), X ray diffractometer (XRD), Element Analysis (EA) and Scanning electron microscope (SEM). We also studied the electrochemical properties of the material. The first discharge capacity of the and retained 95 % of the initial capacity after 100 cycles. The LiFePO4/C obtained shows a good electrochemical capacity and cycle ability at a large current density.

  17. ObsPy: A Python Toolbox for Seismology - Recent Developments and Applications

    Science.gov (United States)

    Megies, T.; Krischer, L.; Barsch, R.; Sales de Andrade, E.; Beyreuther, M.

    2014-12-01

    ObsPy (http://www.obspy.org) is a community-driven, open-source project dedicated to building a bridge for seismology into the scientific Python ecosystem. It offersa) read and write support for essentially all commonly used waveform, station, and event metadata file formats with a unified interface,b) a comprehensive signal processing toolbox tuned to the needs of seismologists,c) integrated access to all large data centers, web services and databases, andd) convenient wrappers to legacy codes like libtau and evalresp.Python, currently the most popular language for teaching introductory computer science courses at top-ranked U.S. departments, is a full-blown programming language with the flexibility of an interactive scripting language. Its extensive standard library and large variety of freely available high quality scientific modules cover most needs in developing scientific processing workflows. Together with packages like NumPy, SciPy, Matplotlib, IPython, Pandas, lxml, and PyQt, ObsPy enables the construction of complete workflows in Python. These vary from reading locally stored data or requesting data from one or more different data centers through to signal analysis and data processing and on to visualizations in GUI and web applications, output of modified/derived data and the creation of publication-quality figures.ObsPy enjoys a large world-wide rate of adoption in the community. Applications successfully using it include time-dependent and rotational seismology, big data processing, event relocations, and synthetic studies about attenuation kernels and full-waveform inversions to name a few examples. All functionality is extensively documented and the ObsPy tutorial and gallery give a good impression of the wide range of possible use cases.We will present the basic features of ObsPy, new developments and applications, and a roadmap for the near future and discuss the sustainability of our open-source development model.

  18. ObsPy: A Python Toolbox for Seismologists, Seismological Observatories and Data Centers

    Science.gov (United States)

    Megies, T.; Barsch, R.; Beyreuther, M.; Krischer, L.; Wassermann, J.

    2012-04-01

    Python combines the possibilities of a full-blown programming language with the flexibility of an interactive scripting language. Its extensive standard library and many freely available high quality scientific modules cover most needs in developing scientific processing workflows. ObsPy extends Python's capabilities to fit the specific needs that arise when working with seismological data. It a) comes with a continuously growing signal processing toolbox that covers the most common tasks in seismological analysis, b) provides read and write support for many common waveform and metadata file formats and c) enables access to various data centers, webservices and databases to retrieve waveform data and station/event metadata. In combination with widely used, free Python packages like NumPy, SciPy, Matplotlib, IPython and PyQt, ObsPy makes it possible to develop complete workflows in Python, ranging from reading locally stored data or requesting data from one or more different data centers via signal analysis and data processing to visualization in GUI applications, output of modified/derived data and creating publication-quality figures. All functionality is extensively documented and the ObsPy Gallery/Tutorial give a good impression of the wide range of use cases. ObsPy is tested and running on Linux, MacOSX and Windows XP/Vista/7 and comes with installation routines for these systems. ObsPy is developed in a test-driven approach and is available under the GPL/LGPLv3 licences. Users are welcome to request help, report bugs or propose enhancements via the user mailing list or the Trac ticket system.

  19. ObsPy: A Python Toolbox for Seismology and Seismological Observatories

    Science.gov (United States)

    Krischer, Lion; Megies, Tobias; Barsch, Robert; Beyreuther, Moritz; Wassermann, Joachim

    2013-04-01

    Python combines the power of a full-blown programming language with the flexibility and accessibility of an interactive scripting language. Its extensive standard library and large variety of freely available high quality scientific modules cover most needs in developing scientific processing workflows. ObsPy extends Python's capabilities to fit the specific needs that arise when working with seismological data. It a) comes with a continuously growing signal processing toolbox that covers most tasks common in seismological analysis, b) provides read and write support for many common waveform, station and event metadata formats and c) enables access to various data centers, webservices and databases to retrieve waveform data and station/event metadata. In combination with mature and free Python packages like NumPy, SciPy, Matplotlib, IPython and PyQt, ObsPy makes it possible to develop complete workflows in Python, ranging from reading locally stored data or requesting data from one or more different data centers via signal analysis and data processing to visualization in GUI and web applications, output of modified/derived data and the creation of publication-quality figures. All functionality is extensively documented and the ObsPy Tutorial and Gallery give a good impression of the wide range of possible use cases. ObsPy is tested and running on Linux, OS X and Windows and comes with installation routines for these systems. ObsPy is developed in a test-driven approach and is available under the GPL/LGPLv3 open source licences. Users are welcome to request help, report bugs, propose enhancements or contribute code via either the user mailing list or the project page on GitHub.

  20. IMPROVEMENT ON SYNTHETIC TECHNOLOGY OF FLUORESCENT BRIGHTENER OB-1%荧光增白剂OB-1合成新工艺

    Institute of Scientific and Technical Information of China (English)

    邓继勇; 易兵

    2001-01-01

    以对甲苯甲腈为原料,经氯化、环化和缩合三步反应合成了荧光增白剂OB-1,通过对化合物进行元素分析、红外光谱以及在DMF中紫外吸收光谱的测定,确定了目标分子.经HPLC测定,产品纯度大于99%.同时,对影响反应的主要工艺条件进行了探讨 .

  1. File list: Oth.EmF.10.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.EmF.10.Kdm4c.AllCell mm9 TFs and others Kdm4c Embryonic fibroblast SRX424018,SR...X424019 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.EmF.10.Kdm4c.AllCell.bed ...

  2. File list: Oth.EmF.05.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.EmF.05.Kdm4c.AllCell mm9 TFs and others Kdm4c Embryonic fibroblast SRX424019,SR...X424018 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.EmF.05.Kdm4c.AllCell.bed ...

  3. File list: Oth.EmF.50.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.EmF.50.Kdm4c.AllCell mm9 TFs and others Kdm4c Embryonic fibroblast SRX424019,SR...X424018 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.EmF.50.Kdm4c.AllCell.bed ...

  4. File list: Oth.EmF.20.Kdm4c.AllCell [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available Oth.EmF.20.Kdm4c.AllCell mm9 TFs and others Kdm4c Embryonic fibroblast SRX424019,SR...X424018 http://dbarchive.biosciencedbc.jp/kyushu-u/mm9/assembled/Oth.EmF.20.Kdm4c.AllCell.bed ...

  5. Synthesis and cytotoxic activity of 2,5-disubstituted pyrimido [5,4-c] quinoline derivatives

    Institute of Scientific and Technical Information of China (English)

    Fan Zhang; Xin Zhai; Li Juan Chen; Jian Guo Qi; Bo Cui; Yu Cheng Gu; Ping Gong

    2011-01-01

    A series of 2,5-disubstituted pyrimido[5,4-c]quinoline derivatives were synthesized and their cytotoxic activity against H460, HT-29 and MDA-MB-231 cell lines was evaluated in vitro. It was found that most of the tested compounds especially compound 17, shown stronger activity to the selected three cell lines than ZM447439.

  6. Thermally induced decomposition of B4C barrier layers in Mo/Si multilayer structures

    NARCIS (Netherlands)

    Bruijn, S.; van de Kruijs, R. W. E.; Yakshin, A. E.; Zoethout, E.; F. Bijkerk,

    2010-01-01

    We investigate the influence of the Mo crystalline state (quasi-amorphous or crystalline) on the thermal stability of Mo/Si thin film multilayers with B4C diffusion barrier layers at either of the two interfaces. We find that multilayers containing amorphous Mo layers are more stable than those cont

  7. Electrochemical Behavior of Al-B4C Metal Matrix Composites in NaCl Solution

    Directory of Open Access Journals (Sweden)

    Yu-Mei Han

    2015-09-01

    Full Text Available Aluminum based metal matrix composites (MMCs have received considerable attention in the automotive, aerospace and nuclear industries. One of the main challenges using Al-based MMCs is the influence of the reinforcement particles on the corrosion resistance. In the present study, the corrosion behavior of Al-B4C MMCs in a 3.5 wt.% NaCl solution were investigated using potentiodynamic polarization (PDP and electrochemical impedance spectroscopy (EIS techniques. Results indicated that the corrosion resistance of the composites decreased when increasing the B4C volume fraction. Al-B4C composite was susceptible to pitting corrosion and two types of pits were observed on the composite surface. The corrosion mechanism of the composite in the NaCl solution was primarily controlled by oxygen diffusion in the solution. In addition, the galvanic couples that formed between Al matrix and B4C particles could also be responsible for the lower corrosion resistance of the composites.

  8. Evaluation plan for a cardiological multi-media workstation (I4C project)

    NARCIS (Netherlands)

    J.W. van der Hofstede (J.); A.B.W.M. Quak (A. B W M); A.M. van Ginneken (Astrid); P.W. MacFarlane (Peter); J. Watson (J.); P.R.H. Hendriks (P. R H); C. Zeelenberg

    1997-01-01

    textabstractThe goal of the I4C project (Integration and Communication for the Continuity of Cardiac Care) is to build a multi-media workstation for cardiac care and to assess its impact in the clinical setting. This paper describes the technical evaluation plan for the prototype.

  9. Evaluation plan for a cardiological multi-media workstation (I4C project)

    NARCIS (Netherlands)

    Hofstede, J.W. van der; Quak, A.B.; Ginneken, A.M. van; Macfarlane, P.W.; Watson, J.; Hendriks, P.R.; Zeelenberg, C.

    1997-01-01

    The goal of the I4C project (Integration and Communication for the Continuity of Cardiac Care) is to build a multi-media workstation for cardiac care and to assess its impact in the clinical setting. This paper describes the technical evaluation plan for the prototype.

  10. Anti-oxidation mechanism of SiC-B4C-C composites

    Institute of Scientific and Technical Information of China (English)

    LIU Qi-cheng; XU Xie-wen; HUANG Qi-zhong; HUANG Bai-yun

    2005-01-01

    Mixture of green petroleum coke, B4C and SiC together with short carbon fiber were employed as starting materials, the mixture was press-formed without any binder after grinding, dense and homogeneous binderless SiC-B4C-C(carbon/ceramic) composites were then obtained after sintering. Composites thus prepared possess excellent anti-oxidation property, that is, mass loss less than 1% within the temperature range from 900 to 1100℃ for 10h. Anti-oxidation mechanism was also discussed from the viewpoint of thermodynamics, excellent anti-oxidation property of materials thus prepared can be discribed to 1) solid SiO2 formed from SiC, which restrains the filtering of oxygen and simultaneously, its volume expansion brought about by the reaction takes roles both walling up the original pores and making the material more compact; 2) liquid B2O3 from the reaction of B4C not only makes the combination with C, B4C and SiC tighter through forming solid solution, but also effect of reaction SiC(s)+2CO(g)=SiO2(s)+3C(s) is an expansive process, which improves the microstructure of the material.

  11. Tribological behavior of liquid metallurgy-processed AA 6061-B4C composites

    Science.gov (United States)

    Monikandan, V. V.; Joseph, M. A.; Rajendrakumar, P. K.; Sreejith, M.

    2015-01-01

    Aluminum metal matrix composites (AMMCs) possess improved properties compared to their monolithic counterparts and serve as a reliable alternative to replace them for applications that are considered as their niche. In the present investigation, 6061 Al alloy-10 wt% B4C composite is fabricated through liquid metallurgy stir casting technique and analyzed for its tribological characteristics. The uniform distribution of B4C reinforcement particles in the composite is achieved by the above route and is characterized using microstructure analysis and x-ray diffraction spectrum. The dry wear tests have been conducted under ambient conditions using a pin-on-disc tribometer. The worn surface and debris of the composite are also characterized using a scanning electron microscope (SEM) and energy-dispersive x-ray spectroscopy (EDS). It is found that the combination of adhesion, delamination and abrasion constitute the predominant wear mechanism and this is influenced by the B4C particles, applied load, sliding distance and speed. The wear and friction coefficient increase with increase in applied load for all the load conditions studied. While the sliding speed fosters the engendering of a mechanically mixed layer (MML) to reduce the wear and friction coefficient, in contrast, the increase in sliding distance scuttles the MML formation owing to abrasion induced by the hard B4C particles.

  12. Verification of the predictive capabilities of the 4C code cryogenic circuit model

    Science.gov (United States)

    Zanino, R.; Bonifetto, R.; Hoa, C.; Richard, L. Savoldi

    2014-01-01

    The 4C code was developed to model thermal-hydraulics in superconducting magnet systems and related cryogenic circuits. It consists of three coupled modules: a quasi-3D thermal-hydraulic model of the winding; a quasi-3D model of heat conduction in the magnet structures; an object-oriented a-causal model of the cryogenic circuit. In the last couple of years the code and its different modules have undergone a series of validation exercises against experimental data, including also data coming from the supercritical He loop HELIOS at CEA Grenoble. However, all this analysis work was done each time after the experiments had been performed. In this paper a first demonstration is given of the predictive capabilities of the 4C code cryogenic circuit module. To do that, a set of ad-hoc experimental scenarios have been designed, including different heating and control strategies. Simulations with the cryogenic circuit module of 4C have then been performed before the experiment. The comparison presented here between the code predictions and the results of the HELIOS measurements gives the first proof of the excellent predictive capability of the 4C code cryogenic circuit module.

  13. Soil Moisture Active Passive Mission L4_C Data Product Assessment (Version 2 Validated Release)

    Science.gov (United States)

    Kimball, John S.; Jones, Lucas A.; Glassy, Joseph; Stavros, E. Natasha; Madani, Nima; Reichle, Rolf H.; Jackson, Thomas; Colliander, Andreas

    2016-01-01

    The SMAP satellite was successfully launched January 31st 2015, and began acquiring Earth observation data following in-orbit sensor calibration. Global data products derived from the SMAP L-band microwave measurements include Level 1 calibrated and geolocated radiometric brightness temperatures, Level 23 surface soil moisture and freezethaw geophysical retrievals mapped to a fixed Earth grid, and model enhanced Level 4 data products for surface to root zone soil moisture and terrestrial carbon (CO2) fluxes. The post-launch SMAP mission CalVal Phase had two primary objectives for each science product team: 1) calibrate, verify, and improve the performance of the science algorithms, and 2) validate accuracies of the science data products as specified in the L1 science requirements. This report provides analysis and assessment of the SMAP Level 4 Carbon (L4_C) product pertaining to the validated release. The L4_C validated product release effectively replaces an earlier L4_C beta-product release (Kimball et al. 2015). The validated release described in this report incorporates a longer data record and benefits from algorithm and CalVal refinements acquired during the SMAP post-launch CalVal intensive period. The SMAP L4_C algorithms utilize a terrestrial carbon flux model informed by SMAP soil moisture inputs along with optical remote sensing (e.g. MODIS) vegetation indices and other ancillary biophysical data to estimate global daily net ecosystem CO2 exchange (NEE) and component carbon fluxes for vegetation gross primary production (GPP) and ecosystem respiration (Reco). Other L4_C product elements include surface (10 cm depth) soil organic carbon (SOC) stocks and associated environmental constraints to these processes, including soil moisture and landscape freeze/thaw (FT) controls on GPP and respiration (Kimball et al. 2012). The L4_C product encapsulates SMAP carbon cycle science objectives by: 1) providing a direct link between terrestrial carbon fluxes and

  14. Influence of synthesis parameters on the properties of LiFePO4/C cathode material☆

    Institute of Scientific and Technical Information of China (English)

    Zhengwei Xiao; Yingjie Zhang; Guorong Hu

    2016-01-01

    The influence of sintering temperature, carbon content and dispersive agent in bal-milling was investigated on the properties of LiFePO4/C prepared using Fe2O3, NH4H2PO4, Li2CO3 and glucose via solid state reaction. X-ray powder diffraction, scanning electron microscopy and charge–discharge test were applied to the characterization of the LiFePO4/C samples synthesized under different conditions. Sintering temperature affects the crystallite/particle size and degree of crystal inity of LiFePO4, formation of Fe2P and maintenance of carbon in LiFePO4/C. Car-bon maintenance is favored by low sintering temperature, and 700 °C is optimum for synthesis of LiFePO4/C with superior electrochemical performance. A higher carbon content in the range of 4.48%–11.03%results in a better rate capability for LiFePO4/C. The dispersive agent used in ball-milling impacts the existent state of carbon in the final product which subsequently determines its charge–discharge behavior. The sample prepared at 700 °C by using acetone as the dispersive agent in bal-milling exhibits an excellent rate capability and capacity retention without any fade at 0.1C, 1C and 2C, with corresponding average discharge capacities of 153.8, 128.3 and 121.0 mA·h·g−1, respectively, in the first 50 cycles.

  15. Adult Workplace Learning Based on 4C Marketing Theory%基于营销学4C 理论的成人工作场所学习

    Institute of Scientific and Technical Information of China (English)

    徐君; 邵庆

    2015-01-01

    Compared with other forms of learning approach , workplace learning has various advantages ,such as clear goals , various forms , obvious effects and so on . It has been one of the important methods of adult learning ,and is being paid attention to increasingly . The 4C marketing theory includes 4 parts :customer ,cost ,convenience ,communication .It has theoretical guidance and practical value to open up the new field - adult workplace learning ,and promote the development of workplace learning theory . On the basics of the 4C marketing theory , we should promote adult workplace learning by the means of meeting consumers’ requirements , reducing cost , providing convenience and effective communication .%工作场所学习相对于其他成人学习方式而言具有目标明确、形式多样、效果明显等优势,已成为成人学习的一种重要方式并日益受到重视。营销学的4C理论由消费者、成本、便利和沟通四个基本要素构成,对于开辟成人工作场所这一“新疆域”,促进工作场所学习的大力发展具有理论指导和实践操作价值。基于此,应从满足双方需求、降低物质和精神成本、提供各种便利条件以及有效沟通四个方面促进成人工作场所学习。

  16. An eclipsing double-line spectroscopic binary at the stellar/substellar boundary in the Upper Scorpius OB association

    CERN Document Server

    Lodieu, N; Hernandez, J I Gonzalez; Sanchis-Ojeda, R; Narita, N; Kawashima, Y; Kawauchi, K; Mascareño, A Suarez; Deeg, H; Arranz, J Prieto; Rebolo, R; Palle, E; Bejar, V J S; Ferragamo, A; Rubiño-Martin, J A

    2015-01-01

    We aim at constraining evolutionary models at low mass and young ages by identifying interesting transiting system members of the nearest OB association to the Sun, Upper Scorpius, targeted by the Kepler mission. We produced light curves for M dwarf members of the USco region surveyed during the second campaign of the Kepler K2 mission. We identified 'by eye' a transiting system, UScoJ161630.68-251220.1 (=EPIC203710387) with a combined spectral type of M5.25 whose photometric, astrometric, and spectroscopic properties makes it a member of USco. We conducted an extensive photometric and spectroscopic follow-up of this transiting system with a suite of telescopes and instruments to characterise the properties of each component of the system. We calculated a transit duration of about 2.42 hours occuring every 2.88 days with a slight difference in transit depth and phase between the two components. We estimated a mass ratio of 0.922+/-0.015 from the semi-amplitudes of the radial velocity curves for each component...

  17. Constraints on the Magellanic Clouds' Interaction from the Distribution of OB Stars and the Kinematics of Giants

    CERN Document Server

    Casetti-Dinescu, Dana I; Girard, Terrence M; van Altena, William F

    2012-01-01

    Young, OB-type candidates are identified in a ~7900 sq-deg. region encompassing the Large and Small Magellanic Clouds (LMC/SMC) periphery, the Bridge, part of the Magellanic Stream (MS) and Leading Arm (LA). Selection is based on UV, optical and IR photometry from existing large-area surveys and proper motions from the Southern Proper Motion 4 catalog (SPM4). The spatial distribution of these young star candidates shows: 1) a well-populated SMC wing which continues westward with two branches partially surrounding the SMC, 2) a rather narrow path from the SMC wing eastward toward the LMC which is offset by 1 to 2 deg. from the high-density H I ridge in the Bridge, 3) a well-populated periphery of the LMC dominated by clumps of stars at the ends of the LMC bar and 4) a few scattered candidates in the MS and two overdensities in the LA regions above and below the Galactic plane. Additionally, a proper-motion analysis is made of a radial-velocity selected sample of red giants and supergiants in the LMC, previousl...

  18. Disc Frequencies for Brown Dwarfs in the Upper Scorpius OB Association: Implications for Brown Dwarf Formation Theories

    CERN Document Server

    Riaz, B; Goodwin, S; Stamatellos, D; Thompson, M

    2011-01-01

    We have investigated the brown dwarf (BD) and stellar disc fractions in the Upper Scorpius OB Association (USco) and compared them with several other young regions. We have compiled the most complete sample of of all spectroscopically confirmed BDs in USco, and have made use of the WISE catalog to identify the disc candidates. We report on the discovery of 12 new BD discs in USco, with spectral type (SpT) between M6 and M8.5. The WISE colors for the new discs are similar to the primordial (transition) discs earlier detected in USco. Combining with previous surveys, we find the lowest inner disc fractions (~20-25%) for a wide range in stellar masses (~0.01-4.0 Msun) in the USco association. The low disc fractions for high-mass stars in USco (and the other clusters) are consistent with an evolutionary decline in inner disc frequency with age. However, BD disc fractions are higher than those for the stars in 1-3 Myr clusters, but very low in the ~5 Myr old USco. Also, primordial BD discs are still visible in the...

  19. Continuous flow microcalorimetric measurement of heat production in white adipose tissue from obese (ob/ob) mice and their lean littermates.

    Science.gov (United States)

    Hansen, E S; Knudsen, J

    1982-12-30

    Heat production, free fatty acid and glycerol release from white adipose tissue fat pads from obese (ob/ob) mice and their lean littermates are determined. Heat production was significantly lower in obese mice compared to lean mice when expressed on wet weight basis but not when expressed on DNA basis. Noradrenaline significantly increased the heat production in fat pads from both groups of animals. However, the increase in heat production due to noradrenaline addition in fat pads from lean mice was significantly higher than in fat pads from obese mice. The release of free fatty acids and glycerol before incubation with noradrenaline was similar from fat pads from both groups of animals. Addition of noradrenaline to the fat pads increased the release of free fatty acids and glycerol in both groups of animals, but the increase was significantly larger from fat pads from lean mice. In the absence of noradrenaline the free fatty acid/glycerol ratio (mol/mol) in the effluent was 7.9:1 and 4.8:1 for lean mice and obese mice, respectively. In the presence of noradrenaline the ratio decreased to 3:1 for both groups of animals.

  20. Multifunctional Bi2ZnOB2O6 single crystals for second and third order nonlinear optical applications

    Science.gov (United States)

    Iliopoulos, K.; Kasprowicz, D.; Majchrowski, A.; Michalski, E.; Gindre, D.; Sahraoui, B.

    2013-12-01

    Bi2ZnOB2O6 nonlinear optical single crystals were grown by means of the Kyropoulos method from stoichiometric melt. The second and third harmonic generation (SHG/THG) of Bi2ZnOB2O6 crystals were investigated by the SHG/THG Maker fringes technique. Moreover, SHG microscopy studies were carried out providing two-dimensional SHG images as a function of the incident laser polarization. The high nonlinear optical efficiency combined with the possibility to grow high quality crystals make Bi2ZnOB2O6 an excellent candidate for photonic applications.

  1. Batch conversion of methane to methanol using Methylosinus trichosporium OB3b as biocatalyst.

    Science.gov (United States)

    Hwang, In Yeub; Hur, Dong Hoon; Lee, Jae Hoon; Park, Chang-Ho; Chang, In Seop; Lee, Jin Won; Lee, Eun Yeol

    2015-03-01

    Recently, methane has attracted much attention as an alternative carbon feedstock since it is the major component of abundant shale and natural gas. In this work, we produced methanol from methane using whole cells of Methylosinus trichosporium OB3b as the biocatalyst. M. trichosporium OB3b was cultured on NMS medium with a supply of 7:3 air/methane ratio at 30°C. The optimal concentrations of various methanol dehydrogenase inhibitors such as potassium phosphate and EDTA were determined to be 100 and 0.5 mM, respectively, for an efficient production of methanol. Sodium formate (40 mM) as a reducing power source was added to enhance the conversion efficiency. A productivity of 49.0 mg/l·h, titer of 0.393 g methanol/l, and conversion of 73.8% (mol methanol/mol methane) were obtained under the optimized batch condition.

  2. BOREAS TGB-8 Photosynthetic Rate Data over the SSA-OBS and the SSA-OJP

    Science.gov (United States)

    Hall, Forrest G. (Editor); Conrad, Sara K. (Editor); Lerdau, Manuel

    2000-01-01

    The BOREAS TGB-8 team collected data to investigate the controls over NMHC fluxes from boreal forest tree species. This data set includes measurements of photosynthetic rates at mature jack pine and black spruce sites. The data were collected at the OJP and OBS tower flux locations in the BOREAS SSA. These areas contained mature stands of jack pine and black spruce and were the focal sites in the BOREAS program for studies of biosphere/atmosphere exchange from these two habitat types. The OBS site is situated in a black spruce/sphagnum bog with the largest trees 155 years old and 10-15 m tall. The OJP site is in a jack pine forest, 80 to 120 years old, which lies on a sandy bench of glacial outwash with the largest tree standing 15 m tall. Temporally, the data cover the period of 24-May-1994 to 19-Sep-1994. The data are stored in tabular ASCII files.

  3. Mathematical Simulation of Flow Phenomena in CAS-OB Refining Ladle

    Institute of Scientific and Technical Information of China (English)

    ZHOU Yun; DONG Yuan-chi; WANG Hai-chuan; WANG Shi-jun; LIU Yong-bing

    2003-01-01

    A mathematical model which describes the fluid flow in a gas stirred original ladle and CAS-OB ladle was introduced. The fluid field analysis was obtained through mathematical simulation. In order to decrease the ladle refractory wearing and increase the heating speed of liquid steel, some measures should be adopted. The result shows that the flow fields in CAS-OB ladle and original ladle are different. With a fixed gas flow rate, the flow field is related to the plug position and the snorkel depth. When the nozzle is located at 0.45 r, where r is the radius of ladle bottom, the fluid field predicted by water modeling is quite satisfactory for improving the quality of liquid steel.

  4. Wavelength assignment algorithm considering the state of neighborhood links for OBS networks

    Science.gov (United States)

    Tanaka, Yu; Hirota, Yusuke; Tode, Hideki; Murakami, Koso

    2005-10-01

    Recently, Optical WDM technology is introduced into backbone networks. On the other hand, as the future optical switching scheme, Optical Burst Switching (OBS) systems become a realistic solution. OBS systems do not consider buffering in intermediate nodes. Thus, it is an important issue to avoid overlapping wavelength reservation between partially interfered paths. To solve this problem, so far, the wavelength assignment scheme which has priority management tables has been proposed. This method achieves the reduction of burst blocking probability. However, this priority management table requires huge memory space. In this paper, we propose a wavelength assignment algorithm that reduces both the number of priority management tables and burst blocking probability. To reduce priority management tables, we allocate and manage them for each link. To reduce burst blocking probability, our method announces information about the change of their priorities to intermediate nodes. We evaluate its performance in terms of the burst blocking probability and the reduction rate of priority management tables.

  5. High-mass x-ray binaries and ob runaway stars

    Directory of Open Access Journals (Sweden)

    L. Kaper

    2004-01-01

    Full Text Available Las binarias masivas de rayos X (HMXBs representan una fase evolutiva importante, y proporcionan infor- maci on sobre las propiedades de las primarias OB y de las secundarias compactas (estrellas de neutrones, agujeros negros. Observaciones recientes indican que las estrellas de neutrones en algunos sistemas (Vela X-1, 4U 1700-37 tienen masas mayores que la masa can onica 1.35 M . Estas observaciones tienen consecuencias importantes para la ecuaci on de estado a densidades supranucleares y para la formaci on de estrellas de neu- trones y agujeros negros (supernovas y estallidos de rayos gama. A consecuencia de la explosi on de supernova que produjo el objeto compacto, las HMXBs tienen velocidades espaciales altas, y son desbocadas. Alter- nativamente, las desbocadas OB pueden ser expelidas de un c umulo mediante interacciones din amicas. Las observaciones del Hipparcos indican que ambos mecanismos entran en juego.

  6. Evaluation of leptin level and Ob gene polymorphism in patients with Behcet's disease.

    Science.gov (United States)

    Okudan, Nilsel; Acar, Hasan; Gökbel, Hakki; Mevlitoğlu, Inci; Sari, Fatih

    2006-08-01

    The present study was aimed to evaluate serum leptin level and the frequency of oligopolymorphic codon 25 (CAA/CAG) of Ob gene in Behcet's disease. Eighty-seven patients with Behcet's disease and 85 healthy controls with matched age, gender and body mass index were included in the study. Serum leptin level was determined and genotype of codon 25 of Ob gene was performed by using the PCR amplification after DNA extraction. Serum leptin concentration of the patients with Behcet's disease (23.8 +/- 22.8 ng/ml) was higher than that of the control groups (17.1 +/- 14.7 ng/ml). The patients with Behcet's disease and control subjects showed CAA/CAA genotype, indicating the presence of no polymorphism. Neither Behcet's disease nor serum leptin level was found to be related to codon 25 polymorphism. We concluded that leptin 25CAG polymorphism is not associated with Behcet's disease and serum leptin level.

  7. ObStruct: a method to objectively analyse factors driving population structure using Bayesian ancestry profiles.

    Directory of Open Access Journals (Sweden)

    Velimir Gayevskiy

    Full Text Available Bayesian inference methods are extensively used to detect the presence of population structure given genetic data. The primary output of software implementing these methods are ancestry profiles of sampled individuals. While these profiles robustly partition the data into subgroups, currently there is no objective method to determine whether the fixed factor of interest (e.g. geographic origin correlates with inferred subgroups or not, and if so, which populations are driving this correlation. We present ObStruct, a novel tool to objectively analyse the nature of structure revealed in Bayesian ancestry profiles using established statistical methods. ObStruct evaluates the extent of structural similarity between sampled and inferred populations, tests the significance of population differentiation, provides information on the contribution of sampled and inferred populations to the observed structure and crucially determines whether the predetermined factor of interest correlates with inferred population structure. Analyses of simulated and experimental data highlight ObStruct's ability to objectively assess the nature of structure in populations. We show the method is capable of capturing an increase in the level of structure with increasing time since divergence between simulated populations. Further, we applied the method to a highly structured dataset of 1,484 humans from seven continents and a less structured dataset of 179 Saccharomyces cerevisiae from three regions in New Zealand. Our results show that ObStruct provides an objective metric to classify the degree, drivers and significance of inferred structure, as well as providing novel insights into the relationships between sampled populations, and adds a final step to the pipeline for population structure analyses.

  8. The complete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C

    Directory of Open Access Journals (Sweden)

    Andrey V. Mardanov

    2016-12-01

    Full Text Available Complete mitochondrial genome of the acid-tolerant fungus Penicillium ShG4C, isolated from oxidized sediments of an abandoned polymetallic mine site, has been sequenced using high-throughput sequencing approach. The mitochondrial genome represents a circular DNA molecule with size of 26,725 bp. It encodes a usual set of mitochondrial genes, including 15 protein coding genes, large and small ribosomal RNAs and 27 tRNA genes. All genes are located on H-strand DNA and transcribed in one direction. Taxonomic analysis based on concatenated sequences of mitochondrial proteins confirmed taxonomic position of this fungus within the genus Penicillium. The sequence of the complete mitochondrial genome of Penicillium ShG4C was deposited in DBBJ/EMBL/GenBank under accession number KX931017.

  9. B4C protective coating under irradiation by QSPA-T intensive plasma fluxes

    Science.gov (United States)

    Buzhinskij, O. I.; Barsuk, V. A.; Begrambekov, L. B.; Klimov, N. S.; Otroshchenko, V. G.; Putric, A. B.

    2016-12-01

    The effect of the QSPA-T pulsed plasma irradiation on the crystalline boron carbide B4C coating was examined. The duration of the rectangular plasma pulses was 0.5 ms with an interval of 5-10 min between pulses. The maximum power density in the central part of plasma stream was 1 GW/m2. The coating thickness varied from 20 to 40 μm on different surface areas. Modification of the surface layers and transformation of the coating at elevated temperature under plasma pulse irradiation during four successive series of impulses are described. It is shown that the boron carbide coating withstood the full cycle of tests under irradiation with 100 plasma pulses with peak power density of 1GW/m2. Constitutive surface deterioration was not detected and the boron carbide coating kept crystal structure B4C throughout the irradiation zone at the surface depth no less 2 μm.

  10. Synthesis and characterization of LiFePO4/C composite used as lithium storage electrodes

    Institute of Scientific and Technical Information of China (English)

    胡国荣; 张新龙; 彭忠东; 廖刚; 禹筱元

    2004-01-01

    LiFePO4/C composites with good rate capability and high energy density were prepared by adding sugar to the synthetic precursor. A significant improvement in electrode performance was achieved. The resulting carbon contents in the sample 1 and sample 2 are 3.06% and 4.95% (mass fraction), respectively. It is believed that the synthesis of LiFePO4 with sugar added before heating is a good method because the synthesized particles having uniform small size are covered by carbon. The performance of the cathodes was evaluated using coin cells. The samples were characterized by X-ray diffraction and scanning electron microscope observation. The addition of carbon limits the particles size growth and enables high electron conductivity. The LiFePO4/C composites show very good electrochemical performance delivering about 142 mAh/g specific capacity when being cycled at the C/10 rate. The capacity fade upon cycling is very small.

  11. Cr/B4C multilayer mirrors: Study of interfaces and X-ray reflectance

    Science.gov (United States)

    Burcklen, C.; Soufli, R.; Dennetiere, D.; Polack, F.; Capitanio, B.; Gullikson, E.; Meltchakov, E.; Thomasset, M.; Jérome, A.; de Rossi, S.; Delmotte, F.

    2016-03-01

    We present an experimental study of the effect of layer interfaces on the x-ray reflectance in Cr/B4C multilayer interference coatings with layer thicknesses ranging from 0.7 nm to 5.4 nm. The multilayers were deposited by magnetron sputtering and by ion beam sputtering. Grazing incidence x-ray reflectometry, soft x-ray reflectometry, and transmission electron microscopy reveal asymmetric multilayer structures with a larger B4C-on-Cr interface, which we modeled with a 1-1.5 nm thick interfacial layer. Reflectance measurements in the vicinity of the Cr L2,3 absorption edge demonstrate fine structure that is not predicted by simulations using the currently tabulated refractive index (optical constants) values for Cr.

  12. Determination of Optimum Cutting Parameters for Surface Roughness in Turning AL-B4C Composites

    Science.gov (United States)

    Channabasavaraja, H. K.; Nagaraj, P. M.; Srinivasan, D.

    2016-09-01

    Many materials such as alloys, composites find their applications on the basis of machinability, cost and availability. In the present work, machinability of Aluminium 1100 and Boron carbide (AL+ B4C) composite material is examined by using lathe tool dynometers (BANKA Lathe) by varying the cutting parameters like spindle speed, Depth of cut and Feed rate in 3 levels. Also, surface roughness is measured against the weight % of reinforcement in the composite (0, 4 and 8 %). From the study it is observed that the hardness of a composite material increases with increase in weight % of reinforcement material (B4C) by 26.27 and 66.7 % respectively. The addition of reinforcement materials influences the machinability. The cutting force in both X and Z direction were also found increment with the reinforcement percentage.

  13. Reaction behavior between B4C, 304 grade of stainless steel and Zircaloy at 1473 K

    Science.gov (United States)

    Sasaki, Ryosuke; Ueda, Shigeru; Kim, Sun-Joong; Gao, Xu; Kitamura, Shin-ya

    2016-08-01

    For a better understanding of the decommissioning of the Fukushima-daiichi nuclear power plant, the melting behavior of the control blade and the channel box should be clarified. In Fukushima nuclear reactor, the channel box was made of Zircaloy-4, and the control rode is made of B4C together with stainless steel cladding and sheath. In the study, the interaction among B4C, stainless steel (SUS), and Zircaloy-4 was investigated at 1473 K in either argon or air atmosphere. In argon, Zircaloy is melted by the diffusion of elements from SUS, and SUS was melted at 1473 K by the diffusion of C and B. In air, SUS reacted with B2O3 and formed an oxides melt firstly. Then, the oxidized Zircaloy contacted with this melt and fused. Moreover, the progress of core melting process during severe accident under different atmospheres was firstly discussed.

  14. M4C9 +(M = Ti, V): New gas phase clusters

    Indian Academy of Sciences (India)

    R Selvan; L Gowrishankar; T Pradeep

    2001-10-01

    New metal-carbon clusters, M4C9 +(M = Ti, V), generated using a combined thermal arc discharge evaporation set-up, have been studied with quadrupole mass spectrometry. Reactivities of these clusters have been investigated by means of association reactions with H2O. Metal-carbon clusters of other compositions have also been studied. We speculate on the mechanism of formation of larger metal-carbon clusters.

  15. 美的营销战略转向4C'S

    Institute of Scientific and Technical Information of China (English)

    文武

    2003-01-01

    @@ 在世人关注伊拉克战争、石油价格浮动、欧元对美元不断攀升之时,一场革命已悄悄来临--营销理念的转换席卷中外大企业,4P'S被逐渐抛弃,4C'S大行其道.

  16. The 4C framework for making reasonable adjustments for people with learning disabilities.

    Science.gov (United States)

    Marsden, Daniel; Giles, Rachel

    2017-01-18

    Background People with learning disabilities experience significant inequalities in accessing healthcare. Legal frameworks, such as the Equality Act 2010, are intended to reduce such disparities in care, and require organisations to make 'reasonable adjustments' for people with disabilities, including learning disabilities. However, reasonable adjustments are often not clearly defined or adequately implemented in clinical practice. Aim To examine and synthesise the challenges in caring for people with learning disabilities to develop a framework for making reasonable adjustments for people with learning disabilities in hospital. This framework would assist ward staff in identifying and managing the challenges of delivering person-centred, safe and effective healthcare to people with learning disabilities in this setting. Method Fourth-generation evaluation, collaborative thematic analysis, reflection and a secondary analysis were used to develop a framework for making reasonable adjustments in the hospital setting. The authors attended ward manager and matron group meetings to collect their claims, concerns and issues, then conducted a collaborative thematic analysis with the group members to identify the main themes. Findings Four main themes were identified from the ward manager and matron group meetings: communication, choice-making, collaboration and coordination. These were used to develop the 4C framework for making reasonable adjustments for people with learning disabilities in hospital. Discussion The 4C framework has provided a basis for delivering person-centred care for people with learning disabilities. It has been used to inform training needs analyses, develop audit tools to review delivery of care that is adjusted appropriately to the individual patient; and to develop competencies for learning disability champions. The most significant benefit of the 4C framework has been in helping to evaluate and resolve practice-based scenarios. Conclusion Use of

  17. FY-3A Launched Atop A LM-4C Launch Vehicle

    Institute of Scientific and Technical Information of China (English)

    Rain.L

    2008-01-01

    @@ FY-3A,the first satellite of China's new generation of polar-orbiting meteorological satellites,was launched into space atop a modified LM-4C launch vehicle.The satellite separated from the rocket 19 minutes after the takeoff.Flying at an altitude of 807km with an inclination of 98.8 degrees,the satellite circles in polar orbit 14 times everyday,covering the whole globe twice a day.

  18. Grazing incidence Fe-line telescopes using W/B4C multilayers

    DEFF Research Database (Denmark)

    Joensen, K. D.; Gorenstein, P.; Christensen, Finn Erland;

    1995-01-01

    The loss of throughput observed at higher energies for traditional grazing-incidence X-ray telescopes coated with high-Z elements can be partly countered by employing multilayers on the outermost reflectors. Using 8-keV reflectivity data from a periodic W/B4C multilayer, the expected performance ...... reflectors required by the Kirkpatrick-Baez telescope exists, so that an Fe-line multilayer telescope could be built today...

  19. Characterization of Al–Al{sub 4}C{sub 3} nanocomposites produced by mechanical milling

    Energy Technology Data Exchange (ETDEWEB)

    Santos-Beltrán, A., E-mail: asantos@utchsur.edu.mx [Universidad Tecnológica de Chihuahua Sur, Carr. Chihuahua a Aldama km. 3 S/N, Col. Colinas del León, CP. 31313 Chihuahua, Chih. (Mexico); Goytia-Reyes, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Morales-Rodriguez, H.; Gallegos-Orozco, V. [Universidad Tecnológica de Chihuahua Sur, Carr. Chihuahua a Aldama km. 3 S/N, Col. Colinas del León, CP. 31313 Chihuahua, Chih. (Mexico); Santos-Beltrán, M. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico); Baldenebro-Lopez, F. [Universidad Tecnológica de Chihuahua Sur, Carr. Chihuahua a Aldama km. 3 S/N, Col. Colinas del León, CP. 31313 Chihuahua, Chih. (Mexico); Martínez-Sánchez, R. [Centro de Investigación en Materiales Avanzados (CIMAV), Laboratorio Nacional de Nanotecnología, Miguel de Cervantes No. 120, C.P. 31109 Chihuahua, Chih. (Mexico)

    2015-08-15

    In this work, a mixture of Al–C–Al{sub 4}C{sub 3} nanopowder previously synthesized by mechanical milling and subsequent thermal treatment was used to reinforce the Al matrix. The nanocomposites were fabricated via high-energy ball milling and subsequent sintering process for different periods of time at 550 °C. Hardness and compression tests were performed to evaluate the mechanical properties of the nanocomposites in the as-milled and sintered conditions. According to the results the reinforcement located in the grain boundaries is responsible for the brittle behavior observed in the nanocomposites during the compression test. The combined effect of sintering and precipitation mechanisms produced an evident increase of the strength of the Al matrix at a relatively short sintering time. By using the Rietveld method the crystallite size and microstrain measurements were determined and correlated with the microhardness values. For the proper characterization of the nanoparticles present in the Al matrix, atomic force microscopy and high resolution electron microscopy were used. - Highlights: • Nanostructured Al{sub 4}C{sub 3} reinforcement was fabricated via mechanical milling and heat treatment. • We found a significant increase of the mechanical properties at short sintering times. • The formation of Al{sub 4}C{sub 3} with during sintering time restricted the excessive growth of the crystallite. • Al{sub 4}C{sub 3} located in the grain boundaries causes brittle fracture observed in compression tests. • There is a correlation between, crystallite size and microstrain values with microhardness.

  20. El cúmulo abierto NGC 6167 en la Asociación Ara OB1

    Science.gov (United States)

    Folatelli, G.; Morrell, N. I.; Barbá, R. H.

    We have carried out a spectrophotometric study of the central region of the open cluster NGC 6167. We were motivated to do so by the fact that this cluster could have had a main role in the star formation history of Ara OB1 Association (Arnal et al., 1987, A&A 174, 78), though it had not been thoroughly studied. Particularly, there was no previous research based on CCD data, and even the existence of the cluster itself had been discussed by some authors. By means of CCD photometry and intermediate resolution spectroscopy on images obtained at the Complejo Astronómico El Leoncito (CASLEO, San Juan) we have obtained B and V magnitudes down to V=19 in the central region of the cluster, along with spectral types and radial velocities for 85 stars. This information allowed us to determine for NGC 6167 a distance modulus of 10.5 ± 0.3 and a mean radial velocity of -39 ± 14 km s-1, which are in agreement with the values corresponding to the open cluster NGC 6193 and with the Ara OB1 Association as a whole. We discuss the role of NGC 6167 in the context of Ara OB1.

  1. RGB-D Hand-Held Ob ject Recognition Based on Heterogeneous Feature Fusion

    Institute of Scientific and Technical Information of China (English)

    吕雄; 蒋树强; 王双

    2015-01-01

    Ob ject recognition has many applications in human-machine interaction and multimedia retrieval. However, due to large intra-class variability and inter-class similarity, accurate recognition relying only on RGB data is still a big challenge. Recently, with the emergence of inexpensive RGB-D devices, this challenge can be better addressed by leveraging additional depth information. A very special yet important case of object recognition is hand-held object recognition, as manipulating objects with hands is common and intuitive in human-human and human-machine interactions. In this paper, we study this problem and introduce an effective framework to address it. This framework first detects and segments the hand-held ob ject by exploiting skeleton information combined with depth information. In the ob ject recognition stage, this work exploits heterogeneous features extracted from different modalities and fuses them to improve the recognition accuracy. In particular, we incorporate handcrafted and deep learned features and study several multi-step fusion variants. Experimental evaluations validate the effectiveness of the proposed method.

  2. B fields in OB stars (BOB): Concluding the FORS 2 observing campaign

    Science.gov (United States)

    Schöller, M.; Hubrig, S.; Fossati, L.; Carroll, T. A.; Briquet, M.; Oskinova, L. M.; Järvinen, S.; Ilyin, I.; Castro, N.; Morel, T.; Langer, N.; Przybilla, N.; Nieva, M.-F.; Kholtygin, A. F.; Sana, H.; Herrero, A.; Barbá, R. H.; de Koter, A.; BOB Collaboration

    2017-03-01

    Aims: The B fields in OB stars (BOB) Collaboration is based on an ESO Large Programme to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. Methods: In the framework of this program, we carried out low-resolution spectropolarimetric observations of a large sample of massive stars using FORS 2 installed at the ESO VLT 8 m telescope. Results: We determined the magnetic field values with two completely independent reduction and analysis pipelines. Our in-depth study of the magnetic field measurements shows that differences between our two pipelines are usually well within 3σ errors. From the 32 observations of 28 OB stars, we were able to monitor the magnetic fields in CPD -57° 3509 and HD 164492C, confirm the magnetic field in HD 54879, and detect a magnetic field in CPD -62° 2124. We obtain a magnetic field detection rate of 6 ± 3% for the full sample of 69 OB stars observed with FORS 2 within the BOB program. For the preselected objects with a v sin i below 60 km s-1, we obtain a magnetic field detection rate of 5 ± 5%. We also discuss X-ray properties and multiplicity of the objects in our FORS 2 sample with respect to the magnetic field detections. Based on observations made with ESO Telescopes at the La Silla Paranal Observatory under program ID 191.D-0255(E,G).

  3. On the nature of high reddening of Cygnus OB2 #12 hypergiant

    CERN Document Server

    Maryeva, O V; Goranskij, V P; Dyachenko, V V; Karpov, S V; Malogolovets, E V; Rastegaev, D A

    2016-01-01

    To explain the nature of the high reddening (Av~10 mag) towards one of the most luminous stars in the Galaxy - Cyg OB2 #12 (B5 Ia-0), also known as MT304, we carried out spectro-photometric observations of 24 stars located in its vicinity. We included five new B-stars among the members of Cygnus OB2, and for five more photometrically selected stars we spectroscopically confirmed their membership. We constructed the map of interstellar extinction within 2.5 arcmin radius and found that interstellar extinction increases towards MT304. According to our results the most reddened OB-stars in the association after MT304 are J203240.35+411420.1 and J203239.90+411436.2, located about 15 arcsec away from it. Interstellar extinction towards these stars is about 9 mag. The increase of reddening towards MT304 suggests that the reddening excess may be caused by the circumstellar shell ejected by the star during its evolution. This shell absorbs 1 mag, but its chemical composition and temperature are unclear. We also repor...

  4. B fields in OB stars (BOB): Concluding the FORS2 observing campaign

    CERN Document Server

    Schoeller, M; Fossati, L; Carroll, T A; Briquet, M; Oskinova, L M; Jarvinen, S; Ilyin, I; Castro, N; Morel, T; Langer, N; Przybilla, N; Nieva, M F; Kholtygin, A F; Sana, H; Herrero, A; Barba, R H; de Koter, A

    2016-01-01

    The "B fields in OB stars" (BOB) collaboration is based on an ESO Large Programme, to study the occurrence rate, properties, and ultimately the origin of magnetic fields in massive stars. In the framework of this programme, we carried out low-resolution spectropolarimetric observations of a large sample of massive stars using FORS2 installed at the ESO VLT 8-m telescope. We determined the magnetic field values with two completely independent reduction and analysis pipelines. Our in-depth study of the magnetic field measurements shows that differences between our two pipelines are usually well within 3sigma errors. From the 32 observations of 28 OB stars, we were able to monitor the magnetic fields in CPD-57 3509 and HD164492C, confirm the magnetic field in HD54879, and detect a magnetic field in CPD-62 2124. We obtain a magnetic field detection rate of 6+-3% for the full sample of 69 OB stars observed with FORS2 within the BOB programme. For the pre-selected objects with a v sin i below 60 km/s, we obtain a m...

  5. Cosmic Ray Acceleration by Stellar Associations? The Case of Cygnus OB2

    CERN Document Server

    Butt, Y; Combi, J; Corcoran, M; Dame, T M; Drake, J; Bernado, M M K; Milne, P; Miniati, F; Pohl, M; Reimer, O; Romero, G; Rupen, M P; Butt, Yousaf; Benaglia, Paula; Combi, Jorge; Corcoran, Michael; Dame, Thomas; Drake, Jeremy; Bernado, Marina Kaufman; Milne, Peter; Miniati, Francesco; Pohl, Martin; Reimer, Olaf; Romero, Gustavo; Rupen, Michael

    2003-01-01

    The origins of all extra-solar cosmic rays -- both the ultra high-energy and lower energy Galactic variety -- remain unclear. It has been argued that the large scale shocks and turbulence induced by the multiple interacting supersonic winds from the many hot stars in young stellar associations may play a role in accelerating Galactic cosmic rays -- with or without the associated multiple supernova remnants (eg. Cesarsky & Montmerle, 1983; Bykov 2001). In this context, the report by the HEGRA Cherenkov telescope group of a steady and extended unidentified TeV gamma-ray source lying at the outskirts of Cygnus OB2 is particularly significant. This is the most massive stellar association known in the Galaxy, estimated to contain ~2600 OB type members alone indeed, Cyg OB2 also coincides with the non-variable MeV-GeV range unidentified EGRET source, 3EG 2033+4118. We summarise here the near-simultaneous follow-up observations of the extended TeV source region with the CHANDRA X-ray Observatory and the Very Lar...

  6. Relative Stabilities of Conserved and Non-Conserved Structures in the OB-Fold Superfamily

    Directory of Open Access Journals (Sweden)

    Andrei T. Alexandrescu

    2009-05-01

    Full Text Available The OB-fold is a diverse structure superfamily based on a β-barrel motif that is often supplemented with additional non-conserved secondary structures. Previous deletion mutagenesis and NMR hydrogen exchange studies of three OB-fold proteins showed that the structural stabilities of sites within the conserved β-barrels were larger than sites in non-conserved segments. In this work we examined a database of 80 representative domain structures currently classified as OB-folds, to establish the basis of this effect. Residue-specific values were obtained for the number of Cα-Cα distance contacts, sequence hydrophobicities, crystallographic B-factors, and theoretical B-factors calculated from a Gaussian Network Model. All four parameters point to a larger average flexibility for the non-conserved structures compared to the conserved β-barrels. The theoretical B-factors and contact densities show the highest sensitivity.Our results suggest a model of protein structure evolution in which novel structural features develop at the periphery of conserved motifs. Core residues are more resistant to structural changes during evolution since their substitution would disrupt a larger number of interactions. Similar factors are likely to account for the differences in stability to unfolding between conserved and non-conserved structures.

  7. Cloud Structure of Galactic OB Cluster Forming Regions from Combining Ground and Space Based Bolometric Observations

    CERN Document Server

    Lin, Yuxin; Li, Di; Zhang, Zhiyu; Ginsburg, Adam; Pineda, Jaime E; Qian, Lei; Galván-Madrid, Roberto; McLeod, Anna Faye; Rosolowsky, Erik; Dale, James E; Immer, Katharina; Koch, Eric; Longmore, Steve; Walker, Daniel; Testi, Leonardo

    2016-01-01

    We have developed an iterative procedure to systematically combine the millimeter and submillimeter images of OB cluster-forming molecular clouds, which were taken by ground based (CSO, JCMT, APEX, IRAM-30m) and space telescopes (Herschel, Planck). For the seven luminous ($L$$>$10$^{6}$ $L_{\\odot}$) Galactic OB cluster-forming molecular clouds selected for our analyses, namely W49A, W43-Main, W43-South, W33, G10.6-0.4, G10.2-0.3, G10.3-0.1, we have performed single-component, modified black-body fits to each pixel of the combined (sub)millimeter images, and the Herschel PACS and SPIRE images at shorter wavelengths. The $\\sim$10$"$ resolution dust column density and temperature maps of these sources revealed dramatically different morphologies, indicating very different modes of OB cluster-formation, or parent molecular cloud structures in different evolutionary stages. The molecular clouds W49A, W33, and G10.6-0.4 show centrally concentrated massive molecular clumps that are connected with approximately radia...

  8. Galactic OB associations in the northern Milky Way Galaxy. I - Longitudes 55 deg to 150 deg

    Science.gov (United States)

    Garmany, C. D.; Stencel, R. E.

    1992-01-01

    The literature on all OB associations was reviewed, and their IRAS point source content was studied, between galactic longitude 55 and 150 deg. Only one third of the 24 associations listed by Ruprecht et al. (1981) have been the subject of individual studies designed to identify the brightest stars. Distances to all of these were recomputed using the method of cluster fitting of the B main sequence stars, which makes it poossible to reexamine the absolute magnitude calibration of the O stars, as well as for the red supergiant candidate stars. Also examined was the composite HR diagram for these associations. Associations with the best defined main sequences, which also tend to contain very young clusters, referred to here as OB clusters, have extremely few evolved B and A or red supergiants. Associations with poorly defined main sequences and few OB clusters have many more evolved stars. They also show an effect in the upper HR diagram referred to as a ledge by Fitzpatrick and Garmany (1990) in similar data for the Large Magellanic Cloud. It is suggested that the differences in the associations are not just observational selection effects but represent real differences in age and formation history.

  9. ObsPy – What can it do for data centers and observatories?

    Directory of Open Access Journals (Sweden)

    Joachim Wassermann

    2011-04-01

    Full Text Available Data acquisition by seismic centers relies on real-time systems, like SeisComP3, Antelope and Earthworm. However, these are complex systems that are designed for fast and precisely defined standard real-time analyses. Therefore, it is not a simple task to access or modify internal routines, and to integrate them into custom-processing workflows or to perform in-depth data analyses. Often a library is necessary that provides convenient access to data and allows easy control over all of the operations that are to be performed on the data. ObsPy is such a library, which is designed to access and process seismological waveform data and metadata. We use short and simple examples here to demonstrate how effective it is to use Python for seismological data analysis. Then, we illustrate the general capabilities of ObsPy, and highlight some of its specific aspects that are relevant for seismological data centers and observatories, through presentation of real-world examples. Finally, we demonstrate how the ObsPy library can be used to develop custom graphical user interface applications.

  10. VizieR Online Data Catalog: Deep OB star population in Carina (Mohr-Smith+, 2017)

    Science.gov (United States)

    Mohr-Smith, M.; Drew, J. E.; Napiwotzki, R.; Simon-Diaz, S.; Wright, N. J.; Barentsen, G.; Eisloeffel, J.; Farnhill, H. J.; Greimel, R.; Monguio, M.; Kalari, V.; Parker, Q. A.; Vink, J. S.

    2016-11-01

    The sky positions and photometric measurements from VPHAS+ (and 2MASS) for 14900 candidate OB stars blue-selected from the Carina region of the Galactic plane are set out in the first 24 columns. The optical magnitudes are expressed in the Vega system. These are followed by the parameters and their error estimates obtained from main-sequence fits to the optical/NIR magnitudes, along with the chi-squared measure of goodness of fit (columns 25 to 33). For the 3 degrees of freedom involved, chi-squared values up to 7.82 may be regarded as 'good fits': 5915 objects are good fits in this sense and have estimated effective temperatures high enough to place them into the O-B2 range. The fitting process delivers effective temperatures, (highly uncertain) distance moduli, and the extinction parameters, A0 and RV. Subsequent columns (34 to 37) identify which candidates are: good O-B2 fits; likely to be emission line stars (based on r-Halpha excess); candidate sub-luminous stars; candidate higher-luminosity evolved objects. The 'Notes' in column 38 provide information on cross-identifications to known objects, where these exist. Columns 39 to 49 present spectroscopically-derived parameters and associated errors for the subset of 276 stars with spectra. (1 data file).

  11. RMI, a new OB-fold complex essential for Bloom syndrome protein to maintain genome stability.

    Science.gov (United States)

    Xu, Dongyi; Guo, Rong; Sobeck, Alexandra; Bachrati, Csanad Z; Yang, Jay; Enomoto, Takemi; Brown, Grant W; Hoatlin, Maureen E; Hickson, Ian D; Wang, Weidong

    2008-10-15

    BLM, the helicase mutated in Bloom syndrome, associates with topoisomerase 3alpha, RMI1 (RecQ-mediated genome instability), and RPA, to form a complex essential for the maintenance of genome stability. Here we report a novel component of the BLM complex, RMI2, which interacts with RMI1 through two oligonucleotide-binding (OB)-fold domains similar to those in RPA. The resulting complex, named RMI, differs from RPA in that it lacks obvious DNA-binding activity. Nevertheless, RMI stimulates the dissolution of a homologous recombination intermediate in vitro and is essential for the stability, localization, and function of the BLM complex in vivo. Notably, inactivation of RMI2 in chicken DT40 cells results in an increased level of sister chromatid exchange (SCE)--the hallmark feature of Bloom syndrome cells. Epistasis analysis revealed that RMI2 and BLM suppress SCE within the same pathway. A point mutation in the OB domain of RMI2 disrupts the association between BLM and the rest of the complex, and abrogates the ability of RMI2 to suppress elevated SCE. Our data suggest that multi-OB-fold complexes mediate two modes of BLM action: via RPA-mediated protein-DNA interaction, and via RMI-mediated protein-protein interactions.

  12. OB stars at the lowest Local Group metallicity: GTC-OSIRIS observations of Sextans A

    CERN Document Server

    Camacho, I; Herrero, A; Simón-Díaz, S

    2016-01-01

    Our aim is to find and classify OB stars in Sextans A, to later determine accurate stellar parameters of these blue massive stars in this low metallicity region $(Z \\sim 0.1 \\rm Z_{\\odot})$. Using UBV photometry, the reddening-free index Q and GALEX imaging, we built a list of blue massive star candidates in Sextans A. We obtained low resolution (R $\\sim$ 1000) GTC-OSIRIS spectra for a fraction of them and carried out spectral classification. For the confirmed O-stars we derive preliminary stellar parameters. The target selection criteria and observations were successful and have produced the first spectroscopic atlas of OB-type stars in Sextans A. From the whole sample of 18 observed stars, 12 were classified as early OB-types, including 5 O-stars. The radial velocities of all target stars are in agreement with their Sextans A membership, although three of them show significant deviations. We determined the stellar parameters of the O-type stars using the stellar atmosphere code FASTWIND, and revisited the s...

  13. Structural modifications induced by ion irradiation and temperature in boron carbide B4C

    Science.gov (United States)

    Victor, G.; Pipon, Y.; Bérerd, N.; Toulhoat, N.; Moncoffre, N.; Djourelov, N.; Miro, S.; Baillet, J.; Pradeilles, N.; Rapaud, O.; Maître, A.; Gosset, D.

    2015-12-01

    Already used as neutron absorber in the current French nuclear reactors, boron carbide (B4C) is also considered in the future Sodium Fast Reactors of the next generation (Gen IV). Due to severe irradiation conditions occurring in these reactors, it is of primary importance that this material presents a high structural resistance under irradiation, both in the ballistic and electronic damage regimes. Previous works have shown an important structural resistance of boron carbide even at high neutron fluences. Nevertheless, the structural modification mechanisms due to irradiation are not well understood. Therefore the aim of this paper is to study structural modifications induced in B4C samples in different damage regimes. The boron carbide pellets were shaped and sintered by using spark plasma sintering method. They were then irradiated in several conditions at room temperature or 800 °C, either by favoring the creation of ballistic damage (between 1 and 3 dpa), or by favoring the electronic excitations using 100 MeV swift iodine ions (Se ≈ 15 keV/nm). Ex situ micro-Raman spectroscopy and Doppler broadening of annihilation radiation technique with variable energy slow positrons were coupled to follow the evolution of the B4C structure under irradiation.

  14. Evaluation of drilling Al/B4C composites with carbide drills

    Directory of Open Access Journals (Sweden)

    Ali Rıza Motorcu

    2016-08-01

    Full Text Available In this study, cutting forces and torque was evaluated through Taguchi Method (TM in the drilling of the high density B4C particle reinforced composites, which were produced through powder metallurgy-hot pressing method, with coated and uncoated carbide drills. Cutting speed (18, 25 and 35 m/min, feed rate (0.08, 0.112 and 0.16 mm/rev, coating properties (coated and uncoated and the amounts of particle reinforcement (5%, 10% and 15% B4C were used as the control factors. It was observed that the increased feed rate and particle reinforcement increased the axial force and torque, and decreased the cutting speed. The uncoated drills had a better performance than the coated drills. The amount of B4C reinforcement was observed to be the most effective parameter on the axial force and torque with the contribution ratios of 96.6% and 49.1%, respectively. Moreover, the correlation coefficients (R2 of the first order predictive equations developed for the axial force and torque were calculated as 0.895 and 0.854, respectively.

  15. Wetting of B{sub 4}C by molten Ni–Ti alloys at 1753 K

    Energy Technology Data Exchange (ETDEWEB)

    Lin, Qiaoli, E-mail: lqllinqiaoli@163.com [State Key Laboratory of Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050 (China); Key Laboratory of Automobile Materials, Department of Materials Science and Engineering, Jilin University, Changchun 130025 (China); Sui, Ran [State Key Laboratory of Advanced Non-ferrous Metal Materials, Lanzhou University of Technology, Lanzhou 730050 (China)

    2013-11-15

    Highlights: •The wettability of Ni−B{sub 4}C was significantly improved by Ti addition. •Interfacial microstructures was varied with the increasing of Ti addition. •A bimodal interface was formed by dissolution and reaction at interface. -- Abstract: We investigated the wetting of B{sub 4}C by molten Ni–Ti alloys at 1753 K using a modified sessile drop method. The improved final wettability and the interface microstructure evolution were observed with the increasing of Ti addition. The mechanism of improvement can be mainly ascribed to the formation and distribution of reaction product TiB{sub 2} at liquid–solid interface. Generally, the spreading was driven by the reaction at liquid–solid interface. For Ni–10 at.% Ti/B{sub 4}C, with the dissolution of substrate (i.e., the accumulation of B in liquid) at first, the system then breaking through the thermodynamic conditions for the precipitation of a continuous reaction product layer, and a distinctive bimodal interface was observed finally. The addition of Ti, as a surface-active element, reduced the initial contact angle, and the dissolved B also segregate at surface, and then reduced the final contact angle.

  16. Location of gamma-ray flaring region in quasar 4C +21.35

    CERN Document Server

    Lei, Maichang

    2015-01-01

    4C +21.35 is a flat-spectrum-radio-quasar-type blazar, in which the rapid variability of very high energy (VHE, $E_{\\gamma}\\gtrsim 100$\\,GeV) emission as short as $\\sim$ 10 minutes was observed by MAGIC Cherenkov telescopes, and the VHE spectrum extends up to at least 400\\,GeV. In this paper, by using a flat broad-line region (BLR) structure, we study the location and properties of $\\gamma$-ray emitting region of 4C +21.35 under the constraints of multiwavelength data. We fit three quasi-simultaneous spectral energy distributions (SEDs) using homogeneous one-zone leptonic model, in which the flat BLR with the aperture angle of $\\alpha=25^{\\circ}$ and a spherically symmetric hot dusty torus with the temperature of $T_{\\rm sub}=1200$\\,K, are assumed. The results show that the jet structure of 4C +21.35 is nearly conical with a half-opening angle of $\\theta_{\\rm j}\\simeq 0.29^{\\circ}-0.6^{\\circ}$. Furthermore, the emitting region is located within the BLR clouds and approaches to outer radius of the BLR during t...

  17. Sintering of B{sub 4}C by pressureless liquid phase sintering

    Energy Technology Data Exchange (ETDEWEB)

    Rocha, Rosa Maria da; Melo, Francisco Cristovao Lourenco de, E-mail: rosarocha@iae.cta.br, E-mail: frapi@iae.cta.br [Instituto de Aeronautica e Espaco (IAE/CTA/IAE), Sao Jose dos Campos, SP (Brazil). Comando-Geral de Tecnologia Aeroespacial. Divisao de Materiais

    2009-07-01

    The effect of three different sintering additive systems on densification of boron carbide powder was investigated. The sintering additives were Al{sub 2}O{sub 3}:Y{sub 2}O{sub 3}, AlN:Y{sub 2}O{sub 3} and BN:Y{sub 2}O{sub 3} compositions. Powder mixtures were prepared with 10 vol% of sintering aids following conventional powder technology processes. Samples were sintered by pressureless sintering at 2050 deg C/30min in argon atmosphere. Sintered samples were compared to a sintered B{sub 4}C without sintering additive. Samples were characterized by XRD to analyze the crystalline phases after sintering and SEM to observe the microstructure and the second phase distribution. YB{sub 4} and YB{sub 2}C{sub 2} were identified in all samples, indicating a reaction between Y{sub 2}O{sub 3}, B{sub 4}C and B{sub 2}O{sub 3} present at the B{sub 4}C particle surface. The best densification result was achieved with Al{sub 2}O{sub 3}:Y{sub 2}O{sub 3} additive system, showing 92.0 % of theoretical density, low porosity and 15.2 % of linear shrinkage. But this sample showed the highest weight loss. (author)

  18. Preparation and investigation of Al–4 wt% B4C nanocomposite powders using mechanical milling

    Indian Academy of Sciences (India)

    A Alizadeh; E Taheri-Nassaj; H R Baharvandi

    2011-08-01

    Boron carbide nanoparticles were produced using commercially available boron carbide powder (0.8 m).Mechanical milling was used to synthesize Al nanostructured powder in a planetary ball-mill under argon atmosphere up to 20 h. The same process was applied for Al–4 wt% B4C nanocomposite powders to explore the role of nanosize reinforcements on mechanical milling stages. Scanning electron microscopy (SEM) analysis as well as apparent density measurements were used to optimize the milling time needed for completion of the mechanical milling process. The results show that the addition of boron carbide particles accelerate the milling process, leading to a faster work hardening rate and fracture of aluminum matrix. FE-SEM images show that distribution of boron carbide particles in aluminum matrix reaches a full homogeneity when steady state takes place. The better distribution of reinforcement throughout the matrix would increase hardness of the powder. To study the compressibility of milled powder, modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles. For better distribution of reinforcement throughout the matrix, , modified heckel equation was used to consider the pressure effect on yield strength as well as reinforcing role of B4C particles.

  19. Effect of different carbon precursors on properties of LiFePO4/C

    Institute of Scientific and Technical Information of China (English)

    肖政伟; 张英杰; 胡国荣

    2015-01-01

    The anoxic decomposition and influence of carbon precursors on the properties of LiFePO4/C prepared by using Fe2O3 were investigated. X-ray powder diffractometry, Fourier transform infrared spectroscopy (FTIR), scanning electron microscopy (SEM) and carbon content and charge–discharge tests were applied to the characterization of the as-synthesized cathodes. Partial carbon is lost in the anaerobic decomposition of organic precursors and a high hydrogen content leads to a high residual carbon rate. Pyromellitic anhydride and citric acid participate in reactions before and in ball-milling. All the chosen carbon precursors are capable of producing LiFePO4 with high degree of crystallinity and purity. The carbon derived fromα-D-glucose, pyromellitic anhydride, soluble starch, citric acid and polyacrylamide has a loose and porous texture in LiFePO4/C which forms conduction on and between LiFePO4 particles. LiFePO4/C prepared by usingα-D-glucose, pyromellitic anhydride, citric acid and sucrose exhibits appreciable electrochemical performance. Graphite alone is able to enhance the electrochemical performance of LiFePO4 to a limited extent but incapable of preparing practical cathode.

  20. Preparation and characterization of B4C coatings for advanced research light sources.

    Science.gov (United States)

    Störmer, Michael; Siewert, Frank; Sinn, Harald

    2016-01-01

    X-ray optical elements are required for beam transport at the current and upcoming free-electron lasers and synchrotron sources. An X-ray mirror is a combination of a substrate and a coating. The demand for large mirrors with single layers consisting of light or heavy elements has increased during the last few decades; surface finishing technology is currently able to process mirror lengths up to 1 m with microroughness at the sub-nanometre level. Additionally, thin-film fabrication is able to deposit a suitable single-layer material, such as boron carbide (B4C), some tens of nanometres thick. After deposition, the mirror should provide excellent X-ray optical properties with respect to coating thickness errors, microroughness values and slope errors; thereby enabling the mirror to transport the X-ray beam with high reflectivity, high beam flux and an undistorted wavefront to an experimental station. At the European XFEL, the technical specifications of the future mirrors are extraordinarily challenging. The acceptable shape error of the mirrors is below 2 nm along the whole length of 1 m. At the Helmholtz-Zentrum Geesthacht (HZG), amorphous layers of boron carbide with thicknesses in the range 30-60 nm were fabricated using the HZG sputtering facility, which is able to cover areas up to 1500 mm long by 120 mm wide in one step using rectangular B4C sputtering targets. The available deposition area is suitable for the specified X-ray mirror dimensions of upcoming advanced research light sources such as the European XFEL. The coatings produced were investigated by means of X-ray reflectometry and interference microscopy. The experimental results for the B4C layers are discussed according to thickness uniformity, density, microroughness and thermal stability. The variation of layer thickness in the tangential and sagittal directions was investigated in order to estimate the achieved level of uniformity over the whole deposition area, which is considerably

  1. Preparation and characterization of B4C coatings for advanced research light sources

    Science.gov (United States)

    Störmer, Michael; Siewert, Frank; Sinn, Harald

    2016-01-01

    X-ray optical elements are required for beam transport at the current and upcoming free-electron lasers and synchrotron sources. An X-ray mirror is a combination of a substrate and a coating. The demand for large mirrors with single layers consisting of light or heavy elements has increased during the last few decades; surface finishing technology is currently able to process mirror lengths up to 1 m with microroughness at the sub-nanometre level. Additionally, thin-film fabrication is able to deposit a suitable single-layer material, such as boron carbide (B4C), some tens of nanometres thick. After deposition, the mirror should provide excellent X-ray optical properties with respect to coating thickness errors, microroughness values and slope errors; thereby enabling the mirror to transport the X-ray beam with high reflectivity, high beam flux and an undistorted wavefront to an experimental station. At the European XFEL, the technical specifications of the future mirrors are extraordinarily challenging. The acceptable shape error of the mirrors is below 2 nm along the whole length of 1 m. At the Helmholtz-Zentrum Geesthacht (HZG), amorphous layers of boron carbide with thicknesses in the range 30–60 nm were fabricated using the HZG sputtering facility, which is able to cover areas up to 1500 mm long by 120 mm wide in one step using rectangular B4C sputtering targets. The available deposition area is suitable for the specified X-ray mirror dimensions of upcoming advanced research light sources such as the European XFEL. The coatings produced were investigated by means of X-ray reflectometry and interference microscopy. The experimental results for the B4C layers are discussed according to thickness uniformity, density, microroughness and thermal stability. The variation of layer thickness in the tangential and sagittal directions was investigated in order to estimate the achieved level of uniformity over the whole deposition area, which is

  2. Characterization of the Young Open Cluster G144.9+0.4 in the Camelopardalis OB1 Association

    CERN Document Server

    Lin, Chien-Cheng; Panwar, Neelam

    2013-01-01

    Our star-count analysis of the 2MASS point sources resulted in an identification of the star cluster G144.9+0.4. The cluster was found, but not characterized, by \\citet{glu10}. We show that the cluster is physically associated with the Cam\\,OB1 association at a distance of about 1 kpc and with an age of 1--2 Myr. Pre-main sequence stars are identified, on the basis of photometric and proper motion data. A total of 91 additional OB star candidates were found in the subgroup 1A and 1B, a significant increase from the currently known 43 OB stars. The OB members show an age spread that indicates a sustained star formation for at least the last 10--15 years. The young cluster G144.9+0.4 represents the latest episode of sequence star formation in this cloud complex.

  3. ObsPy: A Python Toolbox for Seismology/Seismological Observatories

    Science.gov (United States)

    Megies, T.; Barsch, R.; Beyreuther, M.; Krischer, L.; Wassermann, J. M.; ObsPy Development Team

    2011-12-01

    Python enables the user to combine the possibilities of a full-blown programming language with the flexibility of an interactive scripting language. Its extensive standard library and many freely available high quality scientific modules cover most needs in developing scientific processing workflows. The goal of the ObsPy project (http://www.obspy.org) is to facilitate rapid application development for seismology by extending Python's capabilities to fit the specific needs that arise when working with seismological data. It provides read and write support for many common waveform file formats (e.g. MiniSEED, SAC, GSE2, SEISAN, ...) and metadata formats (e.g. SEED, Dataless SEED, XML-SEED, RESP, ...). Several available client modules make it possible to directly acquire waveform data and metadata as well as earthquake event data from data centers communicating with ArcLink (http://www.webdc.eu), Fissures (http://www.iris.edu/dhi) and SeisHub servers (http://www.seishub.org) and by connecting to webservices provided by IRIS (http://www.iris.edu/ws/) and NERIES (http://www.seismicportal.eu/). Finally there is a growing signal processing toolbox that covers many often needed routines for filtering, triggering, instrument correction/simulation, complex trace analysis, array analysis and many more. Recent additions to ObsPy include calculation of probabilistic power spectral densities, relative instrument calibration and wrappers for the IASPEI-tau traveltime package and IRIS's evalresp. In combination with well developed, free Python packages like NumPy (http://numpy.scipy.org), SciPy (http://scipy.org), IPython (http://ipython.scipy.org), Matplotlib (http://matplotlib.sourceforge.net) and PyQt (http://www.riverbankcomputing.co.uk/software/pyqt), ObsPy makes it possible to develop complete workflows in Python, ranging from reading/requesting data via signal analysis and data processing to visualization in GUI applications and output of modified or derived data. ObsPy is

  4. A multi-epoch XMM-Newton campaign on the core of the massive Cygnus OB2 association

    Science.gov (United States)

    Rauw, G.

    2011-12-01

    Context. Cyg OB2 is one of the most massive associations of O-type stars in our Galaxy. Despite the large interstellar reddening towards Cyg OB2, many studies, spanning a wide range of wavelengths, have been conducted to more clearly understand this association. X-ray observations provide a powerful tool to overcome the effect of interstellar absorption and study the most energetic processes associated with the stars in Cyg OB2. Aims: We analyse XMM-Newton data to investigate the X-ray and UV properties of massive O-type stars as well as low-mass pre-main sequence stars in Cyg OB2. Methods: We obtained six XMM-Newton observations of the core of Cyg OB2. In our analysis, we pay particular attention to the variability of the X-ray bright OB stars, especially the luminous blue variable candidate Cyg OB2 #12. Results: We find that X-ray variability is quite common among the stars in Cyg OB2. Whilst short-term variations are restricted mostly to low-mass pre-main sequence stars, one third of the OB stars display long-term variations. The X-ray flux of Cyg OB2 #12 varies by 37%, over timescales from days to years, whilst its mean log LX/Lbol amounts to - 6.10. Conclusions: These properties suggest that Cyg OB2 #12 is either an interacting-wind system or displays a magnetically confined wind. Two other X-ray bright O-type stars (MT91 516 and CPR2002 A11) display variations that suggest they are interacting wind binary systems. Based on observations collected with XMM-Newton, an ESA Science Mission with instruments and contributions directly funded by ESA Member States and the USA (NASA).Full Table 2 and Table 4 are only available in electronic form at the CDS via anonymous ftp to cdsarc.u-strasbg.fr (130.79.128.5) or via http://cdsarc.u-strasbg.fr/viz-bin/qcat?J/A+A/536/A31

  5. Lifetime Estimation of the Nanophosphate LiFePO4/C Battery Chemistry Used in Fully Electric Vehicles

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Loan; Stroe, Ana-Irina

    2015-01-01

    , and intrinsic safety of the nanophosphate LiFePO4/C Li-ion chemistry make it possible to consider this chemistry for electric vehicle (EV) applications. This paper investigates the lifetime of the nanophosphate LiFePO4/C battery chemistry when it is used for full electrical vehicles. The investigation...... is used to study the capacity and power capability degradation behavior of the tested nanophosphate LiFePO4/C battery for two EV operational scenarios....

  6. Suitability of the Nanophosphate LiFePO4/C Battery Chemistry for the Fully Electric Vehicle

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Ioan; Stan, Ana-Irina

    2014-01-01

    , and intrinsic safety of the nanophosphate LiFePO4/C lithium ion chemistry make it possible to consider this chemistry for electric vehicle applications. This paper investigates the lifetime of the nanophosphate LiFePO4/C battery chemistry when it is used for full electrical vehicles. The investigation...... is used to study the capacity and power capability degradation behaviour of the tested nanophosphate LiFePO4/C battery for two electric vehicle operational scenarios....

  7. Synthetic LiFePO4/C without using inert gas

    Institute of Scientific and Technical Information of China (English)

    Guo Rong Hu; Xu Guang Gao; Zhong Dong Peng; Ke Du; Yan Jun Liu

    2007-01-01

    LiFePO4/C was synthesized by high temperature solid-state method with cheap Fe2O3, LiH2PO4 and glucose as raw materials in absence of inert gas. The sample had ordered olivine-type structure other impurities characterized by the test of X-ray diffraction(XRD). The charge-discharge test showed the sample could demonstrate 120.5 mAh/g at 0.2C rate with good cyclic capability. The powder microelectrode cyclic voltammetry test indicated that the redox process of the sample had good reversibility.

  8. Preparation of AlB sub 4 C composites for image analysis

    Energy Technology Data Exchange (ETDEWEB)

    Kelly, A.M.; Reiswig, R.D.; Hill, M.A.; Blumenthal, W.R.

    1990-01-01

    Composites made by infiltrating B{sub 4}C networks with aluminium, or its alloys are of interest for lightweight armor applications. Image analysis plays an important part in correlating the microstructures of such composites with their mechanical properties. Accurate image analysis requires a high degree of perfection in the metallographic preparation, which is particularly difficult where the phases present have such disparate hardness and reactivities. Two preparation procedures have been developed that produce adequate contrast and definition for analysis of key microstructural features. 8 refs., 5 figs., 1 tab.

  9. CT image digital measurement and clinical significance of C4 -C6 anterior fixed parameter

    Institute of Scientific and Technical Information of China (English)

    LI Xiaohe; LI Zhijun; GAO Shang

    2015-01-01

    Objective:To measure C3-C5 anterior fixed parametersment for the segmental anterior fixation surgery. Methods:The examination of the cervical spine in patients with CT imaging data were randomly selected from January 2009 - December 2012 , C4 - C6 cervical no lesions in 35 cases of imaging data were selected (20 males and 5 females , 25 to 50 years old, average 41. 2 years) ,The image data were rebuilded and measured di-ameter by Mimics 16. 01 software, vertebral body height, vertebrae transverse process hole diameter and diameter around, the left and right sides of the horizontal distance between the flange hole inside, left and right sides of the axis of the pedicle and sagittal axis and the horizontal axis angle and length were measured. Results and conclu-sion:the vertebral body diameter of C4-C6, (26. 67±0. 25) mm gradually increased to (32. 89±0. 12) mm, an-terior and posterior diameter of C4 -C6 ,(6. 89±0. 12) mm gradually increased to (8. 85±0. 44) mm, comparing differences between different segments were statistical significance;Vertebral body midline sagittal anterior, middle and posterior height from C4 [anterior was (7. 99 ±0. 51) mm, middle was(7. 09±0. 42) mm, posterior was (7. 76±0. 49) mm]. To C6 [anterior was (9. 89±0. 45 mm, middle was (8. 42±0. 75) mm, posterior was (8. 84±0. 26) mm], vertebral bodies were significant difference (P<0. 05); the vertebrae transverse process hole diameter and diameter around anterior and posterior were gradually increased with the increase of the sequence; on both sides of C4~C6 were by transverse process hole inside edge distance ( 25 . 10 ± 0 . 45 ) mm gradually increased to (28. 89±0. 56) mm, comparing differences between different segments were statistical significance;Pedicle axis , the sagittal axis and horizontal axis angle and length were gradually increasing with the increase of the cervical spine ordinal, difference is statistically significant.

  10. Fermi LAT and Swift flare of the FSRQ 4C +40.25

    Science.gov (United States)

    Carpenter, Bryce; Ojha, Roopesh; Pivato, Giovanna; Fermi Large Area Telescope Collaboration

    2015-11-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed a gamma-ray flare from a source positionally consistent with the flat spectrum radio quasar (FSRQ) 4C +40.25 (also known as B2 1020+40 and 3FGL J1023.1+3952, Acero et al. 2015, ApJS 218, 23) with coordinates RA: 10h 23m 11.5661s, Dec: 39d 48m 15.378s, J2000, (Helmboldt et al. 2007, ApJ, 658, 203) and a redshift of 1.254 (Xu et al. 1994, AJ, 108, 395).

  11. Massive Variability Surveys from Venezuela

    OpenAIRE

    Briceno, Cesar

    2003-01-01

    At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formatio...

  12. 4C 的(r1,r2,r3,r4)−冠的优美性%The gracefulness of the (r1, r2, r3, r4)−corona of the cycle 4C

    Institute of Scientific and Technical Information of China (English)

    吴跃生

    2012-01-01

      讨论了圈4C 的( r r 21,,, r r 43)−冠的优美性,用构造性的方法给出了圈4C 的( r r 21,,, r r 43)−冠的优美标号。证明了圈4C 的( r r 21,,, r r 43)−冠都是交错图。%  Discussed the gracefulness of the( r r 2 1 , , , r r 4 3 )−corona of the cycle 4C .The graceful labeling was given.Proved that the( r r 2 1 , , , r r 4 3 )−corona of the cycle 4C are graceful graph.

  13. Proteomic analysis of male 4C germ cell proteins involved in mouse meiosis.

    Science.gov (United States)

    Guo, Xuejiang; Zhang, Ping; Qi, Yujuan; Chen, Wen; Chen, Xiangxiang; Zhou, Zuomin; Sha, Jiahao

    2011-01-01

    Male meiosis is a specialized type of cell division that gives rise to sperm. Errors in this process can result in the generation of aneuploid gametes, which are associated with birth defects and infertility in humans. Until now, there has been a lack of a large-scale identification of proteins involved in male meiosis in mammals. In this study, we report the high-confidence identification of 3625 proteins in mouse male germ cells with 4C DNA content undergoing meiosis I. Of these, 397 were found to be testis specific. Bioinformatics analysis of the proteome led to the identification of 28 proteins known to be essential for male meiosis in mice. We also found 172 proteins that had yeast orthologs known to be essential for meiosis. Chromosome distribution analysis of the proteome showed underrepresentation of the identified proteins on the X chromosome, which may be due to meiotic sex chromosome inactivation. Characterization of the proteome of 4C germ cells from mouse testis provides an inventory of proteins, which is useful for understanding meiosis and the mechanisms of male infertility.

  14. Multifrequency Studies of the Peculiar Quasar 4C +21.35 During the 2010 Flaring Activity

    CERN Document Server

    Ackermann, M; Allafort, A; Antolini, E; Barbiellini, G; Bastieri, D; Bellazzini, R; Bissaldi, E; Bonamente, E; Bregeon, J; Brigida, M; Bruel, P; Buehler, R; Buson, S; Caliandro, G A; Cameron, R A; Caraveo, P A; Cavazzuti, E; Cecchi, C; Chaves, R C G; Chekhtman, A; Chiang, J; Chiaro, G; Ciprini, S; Claus, R; Cohen-Tanugi, J; Conrad, J; Cutini, S; D'Ammando, F; de Palma, F; Dermer, C D; Silva, E do Couto e; Donato, D; Drell, P S; Favuzzi, C; Finke, J; Focke, W B; Franckowiak, A; Fukazawa, Y; Fusco, P; Gargano, F; Gasparrini, D; Gehrels, N; Giglietto, N; Giordano, F; Giroletti, M; Godfrey, G; Grenier, I A; Guiriec, S; Hayashida, M; Hewitt, J W; Horan, D; Hughes, R E; Iafrate, G; Johnson, A S; Knodlseder, J; Kuss, M; Lande, J; Larsson, S; Latronico, L; Longo, F; Loparco, F; Lovellette, M N; Lubrano, P; Mayer, M; Mazziotta, M N; McEnery, J E; Michelson, P F; Mizuno, T; Monzani, M E; Morselli, A; Moskalenko, I V; Murgia, S; Nemmen, R; Nuss, E; Ohsugi, T; Orienti, M; Orlando, E; Perkins, J S; Pesce-Rollins, M; Piron, F; Pivato, G; Porter, T A; Rainò, S; Razzano, M; Reimer, A; Reimer, O; Sanchez, D A; Schulz, A; Sgrò, C; Siskind, E J; Spandre, G; Spinelli, P; Stawarz, L; Takahashi, H; Takahashi, T; Thayer, J G; Thayer, J B; Thompson, D J; Tinivella, M; Torres, D F; Tosti, G; Troja, E; Usher, T L; Vandenbroucke, J; Vasileiou, V; Vianello, G; Vitale, V; Werner, M; Winer, B L; Wood, D L; Wood, K S; Aleksic, J; Ansoldi, S; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; de Almeida, U Barres; Barrio, J A; Gonzalez, J Becerra; Bednarek, W; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; Fidalgo, D Carreto; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Covino, S; Da Vela, P; Dazzi, F; De Angelis, A; De Caneva, G; De Lotto, B; Mendez, C Delgado; Doert, M; Dominguez, A; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Farina, E; Ferenc, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Lopez, R J Garcia; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Giavitto, G; Godinovic, N; Munoz, A Gonzalez; Gozzini, S R; Hadasch, D; Herrero, A; Hildebrand, D; Hose, J; Hrupec, D; Idec, W; Kadenius, V; Kellermann, H; Knoetig, M L; Kodani, K; Konno, Y; Krause, J; Kubo, H; Kushida, J; La Barbera, A; Lelas, D; Lewandowska, N; Lindfors, E; Lombardi, S; Lopez, M; Lopez-Coto, R; Lopez-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martinez, M; Mazin, D; Menzel, U; Meucci, M; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Niedzwiecki, A; Nishijima, K; Nilsson, K; Nowak, N; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Partini, S; Persic, M; Prada, F; Moroni, P G Prada; Prandini, E; Preziuso, S; Puljak, I; Reinthal, R; Rhode, W; Ribo, M; Rico, J; Garcia, J Rodriguez; Rugamer, S; Saggion, A; Saito, T; Saito, K; Salvati, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpaa, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Stamatescu, V; Stamerra, A; Steinbring, T; Storz, J; Sun, S; Suric, T; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzic, T; Tescaro, D; Teshima, M; Thaele, J; Tibolla, O; Toyama, T; Treves, A; Vogler, P; Wagner, R M; Zandanel, F; Zanin, R; Aller, M F; Angelakis, E; Blinov, D A; Djorgovski, S G; Drake, A J; Efimova, N V; Gurwell, M A; Homan, D C; Jordan, B; Kopatskaya, E N; Kovalev, Y Y; Kurtanidze, O M; Lahteenmaki, A; Larionov, V M; Lister, M L; Nieppola, E; Nikolashvili, M G; Ros, E; Savolainen, T; Sigua, L A; Tornikoski, M; .,

    2014-01-01

    The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) gamma-ray emission from 4C +21.35 (PKS 1222+216) by MAGIC on 2010 June 17, triggered by the high activity detected by the Fermi Large Area Telescope (LAT) in high energy (HE; E > 100 MeV) gamma-rays, poses intriguing questions on the location of the gamma-ray emitting region in this flat spectrum radio quasar (FSRQ). We present multifrequency data of 4C +21.35 collected from centimeter to VHE during 2010 to investigate the properties of this source and discuss a possible emission model. The first hint of detection at VHE was observed by MAGIC on 2010 May 3, soon after a gamma-ray flare detected by Fermi-LAT that peaked on April 29. The same emission mechanism may therefore be responsible for both the HE and VHE emission during the 2010 flaring episodes. Two optical peaks were detected on 2010 April 20 and June 30, close in time but not simultaneous with the two gamma-ray peaks, while no clear connection was observed between the X-ray an gam...

  15. On the Merging Cluster Abell 578 and Its Central Radio Galaxy 4C +67.13

    CERN Document Server

    Hagino, K; Siemiginowska, A; Cheung, C C; Koziel-Wierzbowska, D; Szostek, A; Madejski, G; Harris, D E; Simionescu, A; Takahashi, T

    2015-01-01

    Here we analyze radio, optical, and X-ray data for a peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy, CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation $\\sim$10 kpc, the brighter of which hosts the radio source 4C +67.13. The Fanaroff-Riley type-II radio morphology of 4C +67.13 is unusual for central radio galaxies in local Abell clusters. Our new optical spectroscopy revealed that both nuclei of the CGPG 0719.8+6704 pair are active, albeit at low accretion rates corresponding to the Eddington ratio $\\sim10^{-4}$ (for the estimated black hole masses of $\\sim 3 \\times 10^8\\,M_\\odot$ and $\\sim 10^9 \\, M_\\odot$). The gathered X-ray ({\\it Chandra}) data allowed us to confirm and to quantify robustly the previously noted elongation of the gaseous atmosphere in the dominant sub-cluster, as well as a large spatial offset ($\\sim 60$\\,kpc projected) between the position of the brightest cluster galaxy and...

  16. Consolidation of B4C-TaB2 eutectic composites by spark plasma sintering

    Directory of Open Access Journals (Sweden)

    Dmytro Demirskyi

    2015-12-01

    Full Text Available The in situ synthesis/consolidation of B4C-TaB2 eutectic composites by spark plasma sintering (SPS is reported. The microstructure–property relations were determined for composites with the B4C-TaB2 eutectic composition as functions of TaB2 content, and TaB2-TaB2 interlamellar spacing. A clear maximum in fracture toughness was identified (∼4.5 MPa m1/2 for eutectic composites with interlamellar spacing between 0.9 and 1.1 μm. The composites with the hypereutectic composition of 40 mol.% TaB2 obtained by SPS exhibited lower Vickers hardness (25–26 GPa but higher indentation fracture toughness (up to 4.9 MPa m1/2 than eutectic composites with 30–35 mol.% of TaB2.

  17. Synthesis of LiFePO4/C composite electrode with enhanced electrochemical performance

    Institute of Scientific and Technical Information of China (English)

    HU Guo-rong; GAO Xu-guang; PENG Zhong-dong; CHEN Zhao-yong; TAN Xian-yan; YU Xiao-yuan

    2005-01-01

    LiFePO4/C composite was synthesized by high temperature solid-state reaction using iron( Ⅱ ) oxalate,ammonium di-hydrogen phosphate and lithium carbonate with a kind of carbohydrate dissolved in the dispersant(ethanol) as carbon sources added to the synthetic precursor. The samples were characterized by X-ray diffraction (XRD), scanning electron microscopy observations(SEM), charge/discharge test, cyclic voltammetry(CV) and carbon analysis. The results show that the synthesis of LiFePO4/C has ordered olivine structure. The carbon has two advantages: optimizing particle size of LiFePO4 and increasing the electronic conductivity and high Li+ diffusivity.The cathode material can demonstrate a charge/discharge flat voltage of 3.4 V(vs Li+/Li). Especially the active material with 15 % and 20% carbohydrate added according to the final product of lithium iron phosphate shows very respectively at 0. 1 C rate and the carbon contents in the final production are only 5.17% and 5.29%, respectively.

  18. Synthesis and electrochemical performance of nano-metastructured LiFePO4/C cathode material.

    Science.gov (United States)

    Zhi, Xiaoke; Liang, Guangchuan; Wang, Li; Cui, Junyan; Yang, Limei

    2010-11-01

    The nano-metastructured LiFePO4/C composites were synthesized by carbothermal reduction method using starch gel as carbon source and dispersing media to obtain high tap density LiFePO4 with excellent electrochemical performance. The raw materials were coated by starch gel as compact precursors, which was sintered at 750 degrees C for 8 h to obtain high-density LiFePO4/C composite aggregated with nano-sized particles. Scanning electron microscopy (SEM) and transmission electron microscopy (TEM) observations showed that the primary particles had an average size of about 50-80 nm and the aggregates had a homogeneous particle size distribution of about 400 nm. The asprepared samples had a shortened lithium-ion diffusion length but with higher tap density, thus leading to the excellent electrochemical performance of the cathode materials. Electrochemical results showed that the samples delivered high discharge capacities of 155.6 and 120.7 mAh/g at 0.2C and 5C rates, respectively, with excellent cycling performance.

  19. AGN Spectral Energy Distribution of GLAST Telescope Network Program Object 4C 29.45

    Science.gov (United States)

    Adkins, J.; Stefaniak, L.; Rapp, S.; Hinckley, B.; Lacy, M.

    2006-06-01

    The Gamma-Ray Large Area Space Telescope (GLAST) to be launched in 2006 has a proposed observing list that includes AGNs and Polars bright enough to be observed optically by amateurs and students. This observing list is maintained by the GLAST Telescope Network (GTN) and includes a number of objects that have yet to be observed by the Spitzer Space Telescope. Our project observed one of these objects, 4C 29.45, with the Spitzer MIPS and the IRAC instruments and also using ground based telescopes. Observations were made in seven infrared bands with Spitzer. Additional observations made from the ground by students, amateur astronomers, and small college observatories in R,V, and I were nearly simultaneous with the Spitzer observations. We have used this data to construct the Spectral Energy Distribution (SED) of 4C 29.45. We compare these data to models of the dust emission from the torus, sychrotron emission from the radio core, and thermal emission from the accretion disk to determine the relative importance of the different emission mechanisms in this object as a function of wavelength.

  20. Preparation and characterization of B{sub 4}C coatings for advanced research light sources

    Energy Technology Data Exchange (ETDEWEB)

    Störmer, Michael, E-mail: michael.stoermer@hzg.de [Helmholtz-Zentrum Geesthacht, Max-Planck-Strasse 1, D-21502 Geesthacht (Germany); Siewert, Frank [Helmholtz-Zentrum Berlin, Albert-Einstein-Strasse 15, 12489 Berlin (Germany); Sinn, Harald [European XFEL GmbH, Albert-Einstein-Ring 19, 22761 Hamburg (Germany)

    2016-01-01

    The challenging specifications for long X-ray mirrors for upcoming free-electron lasers can be achieved, especially for maintaining below 2 nm peak-to-valley shape error along the optical aperture of approximately 1 m-long mirrors. X-ray optical elements are required for beam transport at the current and upcoming free-electron lasers and synchrotron sources. An X-ray mirror is a combination of a substrate and a coating. The demand for large mirrors with single layers consisting of light or heavy elements has increased during the last few decades; surface finishing technology is currently able to process mirror lengths up to 1 m with microroughness at the sub-nanometre level. Additionally, thin-film fabrication is able to deposit a suitable single-layer material, such as boron carbide (B{sub 4}C), some tens of nanometres thick. After deposition, the mirror should provide excellent X-ray optical properties with respect to coating thickness errors, microroughness values and slope errors; thereby enabling the mirror to transport the X-ray beam with high reflectivity, high beam flux and an undistorted wavefront to an experimental station. At the European XFEL, the technical specifications of the future mirrors are extraordinarily challenging. The acceptable shape error of the mirrors is below 2 nm along the whole length of 1 m. At the Helmholtz-Zentrum Geesthacht (HZG), amorphous layers of boron carbide with thicknesses in the range 30–60 nm were fabricated using the HZG sputtering facility, which is able to cover areas up to 1500 mm long by 120 mm wide in one step using rectangular B{sub 4}C sputtering targets. The available deposition area is suitable for the specified X-ray mirror dimensions of upcoming advanced research light sources such as the European XFEL. The coatings produced were investigated by means of X-ray reflectometry and interference microscopy. The experimental results for the B{sub 4}C layers are discussed according to thickness uniformity, density

  1. Perception oro-sensorielle des lipides alimentaires et obésité

    Directory of Open Access Journals (Sweden)

    Besnard Philippe

    2016-05-01

    Full Text Available La gustation est un système dynamique capable d’une adaptation physiologique rapide en réponse aux changements environnementaux permanents qui caractérisent notre alimentation (rythme, qualité, quantité. Basé sur la modulation des seuils de sensibilité gustative, ce système homéostatique contribue à la construction du comportement alimentaire en orientant les choix de consommation. On peut donc penser qu’un dysfonctionnement de ce système régulateur peut avoir un impact sur les habitudes alimentaires et donc, à terme, sur la santé. La mise en évidence récente chez le rongeur (rat, souris qu’une obésité induite par le régime non seulement entraîne une détérioration de la détection orale des lipides mais se traduit également par une préférence accrue pour le «gras», plaide en faveur de cette thèse. Chez l’homme, nos travaux indiquent que les sujets obèses, dont la détection oro-sensorielle des lipides est défectueuse, surconsomment des aliments riches en graisse. Ces données murines et humaines suscitent une question fondamentale : quel est le lien entre lipides, obésité et désordres gustatifs? Cette mini-revue se propose de faire le point des connaissances actuelles sur ce sujet.

  2. ObsPy: A Python toolbox for seismology - Current state, applications, and ecosystem around it

    Science.gov (United States)

    Lecocq, Thomas; Megies, Tobias; Krischer, Lion; Sales de Andrade, Elliott; Barsch, Robert; Beyreuther, Moritz

    2016-04-01

    ObsPy (http://www.obspy.org) is a community-driven, open-source project offering a bridge for seismology into the scientific Python ecosystem. It provides * read and write support for essentially all commonly used waveform, station, and event metadata formats with a unified interface, * a comprehensive signal processing toolbox tuned to the needs of seismologists, * integrated access to all large data centers, web services and databases, and * convenient wrappers to third party codes like libmseed and evalresp. Python, in contrast to many other languages and tools, is simple enough to enable an exploratory and interactive coding style desired by many scientists. At the same time it is a full-fledged programming language usable by software engineers to build complex and large programs. This combination makes it very suitable for use in seismology where research code often has to be translated to stable and production ready environments. It furthermore offers many freely available high quality scientific modules covering most needs in developing scientific software. ObsPy has been in constant development for more than 5 years and nowadays enjoys a large rate of adoption in the community with thousands of users. Successful applications include time-dependent and rotational seismology, big data processing, event relocations, and synthetic studies about attenuation kernels and full-waveform inversions to name a few examples. Additionally it sparked the development of several more specialized packages slowly building a modern seismological ecosystem around it. This contribution will give a short introduction and overview of ObsPy and highlight a number of use cases and software built around it. We will furthermore discuss the issue of sustainability of scientific software.

  3. L’obésité : aspects physiologiques, cellulaires et moléculaires

    Directory of Open Access Journals (Sweden)

    Ferre Pascal

    2003-03-01

    Full Text Available L’obésité est devenu un problème majeur de santé publique avec une prévalence qui dépasse les 30 % dans certaines sociétés occidentales. L’obésité est un reflet du développement excessif du tissu adipeux lié à un stockage massif de lipides sous forme de triglycérides (hypertrophie et hyperplasie adipocytaires et due à un déséquilibre de la balance énergétique (apport\\\\dépenses caloriques. Pour perdre du poids, il faut alors augmenter les dépenses ou diminuer les apports énergétiques. Bien qu’il existe des mécanismes de régulation de la prise alimentaire, leur efficacité dans le sens du stockage est bien plus grande que dans le sens du déstockage. Chez l’homme une régulation de la dépense énergétique qui permettrait de brûler les calories en excès ne semble pas développée. En résumé, nous sommes programmés pour stocker et non pour dépenser, ce qui aurait pu représenter un avantage évolutif important en cas de périodes de famines, seuls survivant alors les plus « gras ». A l’heure actuelle, il n’existe pas de traitement pharmacologique efficace de l’obésité et il paraît donc plus raisonnable d’essayer de prévenir que de guérir.

  4. Winds of low-metallicity OB-type stars: HST-COS spectroscopy in IC 1613

    Energy Technology Data Exchange (ETDEWEB)

    Garcia, Miriam; Najarro, Francisco [Centro de Astrobiología, CSIC-INTA. Ctra. Torrejón a Ajalvir km.4, E-28850 Torrejón de Ardoz, Madrid (Spain); Herrero, Artemio [Instituto de Astrofísica de Canarias. Vía Láctea s/n, E-38200 La Laguna (S. C. Tenerife) (Spain); Lennon, Daniel J. [European Space Astronomy Centre, Camino Bajo del Castillo, E-28692 Villanueva de la Cañada, Madrid (Spain); Urbaneja, Miguel Alejandro [Institute for Astro- and Particle Physics, University of Innsbruck, Technikerstr. 25/8, A-6020 Innsbruck (Austria)

    2014-06-10

    We present the first quantitative ultraviolet spectroscopic analysis of resolved OB stars in IC 1613. Because of its alleged very low metallicity (≲1/10 Z {sub ☉}, from H II regions), studies in this Local Group dwarf galaxy could become a significant step forward from the Small Magellanic Cloud (SMC) toward the extremely metal-poor massive stars of the early universe. We present HST-COS data covering the ∼1150-1800 Å wavelength range with resolution R ∼ 2500. We find that the targets do exhibit wind features, and these are similar in strength to SMC stars. Wind terminal velocities were derived from the observed P Cygni profiles with the Sobolev plus Exact Integration method. The v {sub ∞}-Z relationship has been revisited. The terminal velocity of IC 1613 O stars is clearly lower than Milky Way counterparts, but there is no clear difference between IC 1613 and SMC or LMC analog stars. We find no clear segregation with host galaxy in the terminal velocities of B-supergiants, nor in the v {sub ∞}/v {sub esc} ratio of the whole OB star sample in any of the studied galaxies. Finally, we present the first evidence that the Fe-abundance of IC 1613 OB stars is similar to the SMC, which is in agreement with previous results on red supergiants. With the confirmed ∼1/10 solar oxygen abundances of B-supergiants, our results indicate that IC 1613's α/Fe ratio is sub-solar.

  5. CONSTRAINTS ON THE MAGELLANIC CLOUDS' INTERACTION FROM THE DISTRIBUTION OF OB STARS AND THE KINEMATICS OF GIANTS

    Energy Technology Data Exchange (ETDEWEB)

    Casetti-Dinescu, Dana I.; Girard, Terrence M.; Van Altena, William F. [Astronomy Department, Yale University, P.O. Box 208101, New Haven, CT 06520-8101 (United States); Vieira, Katherine, E-mail: dana.casetti@yale.edu, E-mail: terry.girard@yale.edu, E-mail: william.vanaltena@yale.edu, E-mail: kvieira@cida.ve [Centro de Investigaciones de Astronomia, Apartado Postal 264, Merida 5101-A (Venezuela, Bolivarian Republic of)

    2012-07-10

    Young, OB-type candidates are identified in a {approx}7900 deg{sup 2} region encompassing the Large and Small Magellanic Clouds (LMC/SMC) periphery, the Bridge, part of the Magellanic Stream (MS), and Leading Arm (LA). Selection is based on UV, optical, and IR photometry from existing large-area surveys and proper motions from the Southern Proper Motion 4 (SPM4) catalog. The spatial distribution of these young star candidates shows (1) a well-populated SMC wing which continues westward with two branches partially surrounding the SMC, (2) a rather narrow path from the SMC wing eastward toward the LMC which is offset by 1 Degree-Sign -2 Degree-Sign from the high-density H I ridge in the Bridge, (3) a well-populated periphery of the LMC dominated by clumps of stars at the ends of the LMC bar, and (4) a few scattered candidates in the MS and two overdensities in the LA regions above and below the Galactic plane. Additionally, a proper-motion analysis is made of a radial-velocity-selected sample of red giants and supergiants in the LMC, previously shown to be a kinematically and chemically distinct subgroup, most likely captured from the SMC. SPM4 proper motions of these stars also indicate they are distinct from the LMC population. The observational results presented here, combined with the known orbits of the Clouds and other aspects of the LMC morphology, suggest an off-center, moderate to highly inclined collision between the SMC and the LMC's disk that took place between 100 and 200 Myr ago.

  6. The design, microstructure and tensile properties of B{sub 4}C particulate reinforced 6061Al neutron absorber composites

    Energy Technology Data Exchange (ETDEWEB)

    Chen, H.S. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Wang, W.X., E-mail: Wangwenxian@tyut.edu.cn [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Li, Y.L.; Zhang, P. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China); Nie, H.H. [Shanxi Coal-Mining Administrators College, Taiyuan 030024 (China); Wu, Q.C. [School of Materials Science and Engineering, Taiyuan University of Technology, Taiyuan 030024 (China)

    2015-05-25

    Highlights: • B{sub 4}C/Al composites for neutron shielding were designed by MCNP program. • B{sub 4}C/Al composite were fabricated by vacuum hot pressing followed by hot rolling. • The properties can be enhanced by vacuum hot pressing followed by hot rolling. - Abstract: Based on the Monte Carlo Particle transport program MCNP, a novel boron carbide particulate reinforced 6061Al composite for neutron shielding (B{sub 4}C/6061Al NACs) with high strength and low density was designed. The NACs with four volume fractions (10%, 20%, 30% and 40%) were successfully fabricated by vacuum hot pressing followed by hot rolling (VPHR) in atmospheric environments. The calculation results indicated that the neutron transmission ratio decreased with the increasing of B{sub 4}C content and the thickness of plates. B{sub 4}C particle is uniformly distributed in the matrix, exhibiting the good bonding in interface. The phases of neutron absorbers were mainly B{sub 4}C and Al, and a spot of AlB{sub 2} and Al{sub 3}BC. The grain of the matrix was refined and the dislocation was formed around the particles. With increasing the B{sub 4}C content, the particles gathered, breakage appeared, and the tensile strength of composite first increased and then decreased. The failure mode of B{sub 4}C/6061Al NACs included: the interfacial debonding and the cleavage fracture of particles.

  7. Stagnant Shells in the Vicinity of the Dusty Wolf-Rayet-OB Binary WR 112

    OpenAIRE

    Lau, R. M.; Hankins, M. J.; Schödel, R.; Sanchez-Bermudez, J.; A. F. J. Moffat; Ressler, M. E.

    2016-01-01

    We present high spatial resolution mid-infrared images of the nebula around the late-type carbon-rich Wolf-Rayet (WC)-OB binary system WR~112 taken by the recently upgraded VLT spectrometer and imager for the mid-infrared (VISIR) with the PAH1, NeII\\_2, and Q3 filters. The observations reveal a morphology resembling a series of arc-like filaments and broken shells. Dust temperatures and masses are derived for each of the identified filamentary structures, which exhibit temperatures ranging fr...

  8. Nature vs. Nurture: The influence of OB star environments on proto-planetary disk evolution

    Science.gov (United States)

    Bouwman, Jeroen

    2006-09-01

    We propose a combined IRAC/IRS study of a large, well-defined and unbiased X-ray selected sample of pre-main-sequence stars in three OB associations: Pismis 24 in NGC 6357, NGC 2244 in the Rosette Nebula, and IC 1795 in the W3 complex. The samples are based on recent Chandra X-ray Observatory studies which reliably identify hundreds of cluster members and were carefully chosen to avoid high infrared nebular background. A new Chandra exposure of IC 1795 is requested, and an optical followup to characterise the host stars is planned.

  9. Formation of Al/B4C Surface Nano-composite Layers on 7075 Al Alloy Employing Friction Stir Processing

    Science.gov (United States)

    Kashani-Bozorg, S. F.; Jazayeri, K.

    2009-06-01

    Al/B4C surface nano-composite layers was achieved on commercial 7075 Al substrate employing friction stir processing technique. Agglomeration of B4C particles was occurred after a single pass. The dispersion of B4C particles was found to be affected by the number of FSP passes. A distribution of nano-size B4C particle was achieved after four passes. Moreover, the increasing in number of FSP passes causes a decreasing in matrix grain size of the surface nano-composite layer. The micro hardness of the surface nano-composite layer improves by almost two times as compared to that of the as-received substrate; this is attributed to the finer matrix grains and dispersion of nano-sized B4C particles.

  10. VizieR Online Data Catalog: Periods of 4-10 Myr old T Tauri members of Orion OB1 (Karim+, 2016)

    Science.gov (United States)

    Karim, M. T.; Stassun, K. G.; Briceno, C.; Vivas, A. K.; Raetz, S.; Mateu, C.; Downes, J. J.; Calvet, N.; Hernandez, J.; Neuhauser, R.; Mugrauer, M.; Takahashi, H.; Tachihara, K.; Chini, R.; Cruz-Dias, G. A.; Aarnio, A.; James, D. J.; Hackstein, M.

    2017-02-01

    The Astronomia Variability Survey of Orion (CVSO) was carried out at the Llano del Hato National Astronomical Observatory in Venezuela, with the QUEST CCD mosaic camera (8000*8000pixels) on the 1m (clear aperture) Schmidt telescope, with a plate scale of 1.02''/pixel and field of view of 5.4 deg2. This V-, RC-, and IC-band multi-epoch survey, covering ~180deg2 of the Orion OB1 association, spans a time baseline of 12yr, from 1998 December to 2011 February. The 25 Ori cluster was observed by the 0.6/0.9m Schmidt-type telescope at Jena Observatory (Germany), the two 5.9'' telescopes at Observatorio Cerro Armazones (OCA, Chile), and the 1.5m reflector at the Gunma Astronomical Observatory in Japan, over four observing campaigns during the years 2010-2013. The Jena Schmidt-type telescope was equipped with the optical Schmidt Telescope Camera (STK), with an e2v 42-10 2048*2048 detector, yielding a plate scale of 1.55''/pixel and a field of view of 53'*53', thus encompassing most of the cluster. The Jena 50s exposures, all taken through the R filter, were centered on 25 Ori. A total of 8506 individual exposures were obtained in 108 nights. The Gunma 1.5m reflector observations were carried out by obtaining 60s integrations in R with the Gunma Low-resolution Spectrograph and Imager (GLOWS), which has an e2v CCD55-30 1250*1152 pixel detector with a 0.6''/pixel scale, covering a field of view of 12.5'*11.5'. Observations were obtained during four nights in year 2010. The Observatorio Cerro Armazones observations were done in the R band using the RoBoTT (Robotic Bochum TWin Telescope), which consists of twin Takahashi 150mm aperture apochromatic astrographs, each equipped with an Apogee U16M camera with a KAF-16803 4096*4096 pixel CCD, providing a 2.7°*2.7° field of view with 2.37''/pixel scale. The 60s exposures were centered on 25 Ori, spanning an area much larger than the cluster. OCA data were obtained during all YETI seasons. During the nights of 2006 January 8-15, we

  11. Characterization of LiFePO4/C Composite Thin Films Using Electrochemical Impedance Spectroscopy

    Science.gov (United States)

    Bajars, G.; Kucinskis, G.; Smits, J.; Kleperis, J.; Lusis, A.

    2012-08-01

    The composite LiFePO4/C thin films were prepared on steel substrate by radio frequency (RF) magnetron sputtering. Electrochemical properties of the obtained thin films were investigated by cyclic voltammetry charge-discharge measurements and electrochemical impedance spectroscopy (EIS). The films annealed at 550 °C exhibited a couple of redox peaks at 3.45 V vs. Li/Li+ characteristic for the electrochemical lithium insertion/extraction in LiFePO4. At low current rate such composite thin film showed a discharge capacity of over 110 mAh g-1. The dependence of charge transfer resistance, double layer capacitance and lithium diffusion coefficients on applied electrode potential were calculated from EIS data. Determined values of lithium diffusion coefficient were in the range from 8.3-10-13 cm2 s1 to 1.2-10-13 cm2 s-1 at 3.4 V and 3.7 V, respectively.

  12. Revisiting the electrochemical impedance behaviour of the LiFePO4/C cathode

    Indian Academy of Sciences (India)

    Hua Ju; Jun Wu; Yanhui Xu

    2013-05-01

    In the present work, the electrochemical behaviour of LiFePO4/C electrode has been reported. Specially, the electrochemical impedance spectroscopies (EIS) have been studied in detail. The discharge capacity is more than 120 mAh/g. There are two semicircles being found in the Nyquist plot for the cycled electrode and one semicircle for the as-prepared electrode. It is found that the interface capacitance is in an order of magnitude of 10 F/cm2 for the high-frequency semicircle, while for the second semicircle the interface capacitance is 5.3 ∼ 45.4 × 103 F/cm2. It could be concluded that the high-frequency semicircle is to correspond to the charge transfer process. The function of the carbon layer is also briefly discussed.

  13. Dry Sliding Tribological Studies of AA6061-B4C-Gr Hybrid Composites

    Science.gov (United States)

    Monikandan, V. V.; Joseph, M. A.; Rajendrakumar, P. K.

    2016-10-01

    The dry sliding behavior of stir-cast AA6061-10 wt.% B4C composites containing 2.5, 5 and 7.5 wt.% graphite particles was studied as a function of applied load, sliding speed and sliding distance on a pin-on-disk tribotester. The wear rate and friction coefficient increased with increase in applied load and sliding distance. The increase in graphite addition reduced the increase in wear rate and friction coefficient in the sliding speed range 2-2.5 m/s. Scanning electron microscopy of the worn pin revealed a graphite tribolayer, and transmission electron microscopy revealed overlapping deformation bands under 30 N applied load. Upon increasing the applied load to 40 N, welded region with fine crystalline structure was formed due to dynamic recrystallization of AA6061 alloy matrix.

  14. Solubility of alkali metal halides in the ionic liquid [C4C1im][OTf].

    Science.gov (United States)

    Kuzmina, O; Bordes, E; Schmauck, J; Hunt, P A; Hallett, J P; Welton, T

    2016-06-28

    The solubilities of the metal halides LiF, LiCl, LiBr, LiI, NaF, NaCl, NaBr, NaI, KF, KCl, KBr, KI, RbCl, CsCl, CsI, were measured at temperatures ranging from 298.15 to 378.15 K in the ionic liquid 1-butyl-3-methylimidazolium trifluoromethanesulfonate ([C4C1im][OTf]). Li(+), Na(+) and K(+) salts with anions matching the ionic liquid have also been investigated to determine how well these cations dissolve in [C4C1im][OTf]. This study compares the influence of metal cation and halide anion on the solubility of salts within this ionic liquid. The highest solubility found was for iodide salts, and the lowest solubility for the three fluoride salts. There is no outstanding difference in the solubility of salts with matching anions in comparison to halide salts. The experimental data were correlated employing several phase equilibria models, including ideal mixtures, van't Hoff, the λh (Buchowski) equation, the modified Apelblat equation, and the non-random two-liquid model (NRTL). It was found that the van't Hoff model gave the best correlation results. On the basis of the experimental data the thermodynamic dissolution parameters (ΔH, ΔS, and ΔG) were determined for the studied systems together with computed gas phase metathesis parameters. Dissolution depends on the energy difference between enthalpies of fusion and dissolution of the solute salt. This demonstrates that overcoming the lattice energy of the solid matrix is the key to the solubility of inorganic salts in ionic liquids.

  15. Study of improved electrochemical performance of LiFePO4/C electrode for LIB

    Institute of Scientific and Technical Information of China (English)

    HU; Guo-rong; GAO; Xu-guang; PENG; Zhong-dong

    2005-01-01

    Lithium iron phosphate is a most promising cathode material for Li-ion batteries(LIB).But the key barrier limiting its application is extremely low electronic conductivity. Meanwhile the low electron conductivity can be improved by preparing LiFePO4 with carbon modified. LiFePO4/C was synthesized by high temperature solid-state reaction using iron (Ⅱ) oxalate, ammonium di-hydrogen phosphate and lithium carbonate with a kind of organic compound (CR) that can be dissolved in the dispersant (ethanol) as carbon sources added to the synthetic precursor in this paper.The samples were characterized by X-ray diffraction, scanning electron microscope observations,charge/discharge test, cyclic voltammetry and carbon analysis. It was believed that the synthesized LiFePO4/C with perfect olivine structure by X-ray diffraction. The carbon brought about two advantages: (i) an optimized particle size of LiFePO4, and (ii) increasing the electronic conductivity and Li+ diffusivity. The cathode material could demonstrate a charge/discharge flat voltage of 3.4V (Vs Li+/Li). Especially the active material with 20% organic added according to the final product of LiFePO4 showed very good electrochemical performance reaching about initial 162.0 mAh/g specific capacity at 0. 1C rate and could also keep excellent discharge capacity even at 3C rate (510 mA/g) current and good cycle performance. The carbon content in the final production was only 5.29%(mass fraction).

  16. Englerin A Agonizes the TRPC4/C5 Cation Channels to Inhibit Tumor Cell Line Proliferation.

    Directory of Open Access Journals (Sweden)

    Cheryl Carson

    Full Text Available Englerin A is a structurally unique natural product reported to selectively inhibit growth of renal cell carcinoma cell lines. A large scale phenotypic cell profiling experiment (CLiP of englerin A on ¬over 500 well characterized cancer cell lines showed that englerin A inhibits growth of a subset of tumor cell lines from many lineages, not just renal cell carcinomas. Expression of the TRPC4 cation channel was the cell line feature that best correlated with sensitivity to englerin A, suggesting the hypothesis that TRPC4 is the efficacy target for englerin A. Genetic experiments demonstrate that TRPC4 expression is both necessary and sufficient for englerin A induced growth inhibition. Englerin A induces calcium influx and membrane depolarization in cells expressing high levels of TRPC4 or its close ortholog TRPC5. Electrophysiology experiments confirmed that englerin A is a TRPC4 agonist. Both the englerin A induced current and the englerin A induced growth inhibition can be blocked by the TRPC4/C5 inhibitor ML204. These experiments confirm that activation of TRPC4/C5 channels inhibits tumor cell line proliferation and confirms the TRPC4 target hypothesis generated by the cell line profiling. In selectivity assays englerin A weakly inhibits TRPA1, TRPV3/V4, and TRPM8 which suggests that englerin A may bind a common feature of TRP ion channels. In vivo experiments show that englerin A is lethal in rodents near doses needed to activate the TRPC4 channel. This toxicity suggests that englerin A itself is probably unsuitable for further drug development. However, since englerin A can be synthesized in the laboratory, it may be a useful chemical starting point to identify novel modulators of other TRP family channels.

  17. The Adult Ventricular-Subventricular Zone (V-SVZ) and Olfactory Bulb (OB) Neurogenesis.

    Science.gov (United States)

    Lim, Daniel A; Alvarez-Buylla, Arturo

    2016-05-02

    A large population of neural stem/precursor cells (NSCs) persists in the ventricular-subventricular zone (V-SVZ) located in the walls of the lateral brain ventricles. V-SVZ NSCs produce large numbers of neuroblasts that migrate a long distance into the olfactory bulb (OB) where they differentiate into local circuit interneurons. Here, we review a broad range of discoveries that have emerged from studies of postnatal V-SVZ neurogenesis: the identification of NSCs as a subpopulation of astroglial cells, the neurogenic lineage, new mechanisms of neuronal migration, and molecular regulators of precursor cell proliferation and migration. It has also become evident that V-SVZ NSCs are regionally heterogeneous, with NSCs located in different regions of the ventricle wall generating distinct OB interneuron subtypes. Insights into the developmental origins and molecular mechanisms that underlie the regional specification of V-SVZ NSCs have also begun to emerge. Other recent studies have revealed new cell-intrinsic molecular mechanisms that enable lifelong neurogenesis in the V-SVZ. Finally, we discuss intriguing differences between the rodent V-SVZ and the corresponding human brain region. The rapidly expanding cellular and molecular knowledge of V-SVZ NSC biology provides key insights into postnatal neural development, the origin of brain tumors, and may inform the development regenerative therapies from cultured and endogenous human neural precursors.

  18. A Spitzer View of Mon OB1 East/NGC 2264

    CERN Document Server

    Rapson, Valerie A; Gutermuth, Robert A; Megeath, S Thomas; Allen, Thomas S; Myers, Philip C; Allen, Lori E

    2014-01-01

    We present Spitzer 3.6, 4.5, 5.8, 8.0, and 24 micron images of the Mon OB1 East giant molecular cloud, which contains the young star forming region NGC 2264, as well as more extended star formation. With Spitzer data and 2MASS photometry, we identify and classify young stellar objects (YSOs) with dusty circumstellar disks and/or envelopes in Mon OB1 East by their infrared-excess emission and study their distribution with respect to cloud material. We find a correlation between the local surface density of YSOs and column density of molecular gas as traced by dust extinction that is roughly described as a power law in these quantities. NGC 2264 follows a power law index of ~2.7, exhibiting a large YSO surface density for a given gas column density. Outside of NGC 2264 where the surface density of YSOs is lower, the power law is shallower and the region exhibits a larger gas column density for a YSO surface density, suggesting the star formation is more recent. In order to measure the fraction of cloud members ...

  19. The population of OB supergiants in the starburst cluster Westerlund 1

    CERN Document Server

    Negueruela, Ignacio; Ritchie, Ben W

    2010-01-01

    After leaving the main sequence, massive stars undergo complex evolution, still poorly understood. With a population of 100s OB stars, the starburst cluster Westerlund~1 offers an unparallelled environment to study their evolutionary tracks. We used the VLT/FORS2 to obtain intermediate-resolution spectroscopy over the range 5800-9000A of ~ 100 likely members. We developed criteria for their spectral classification using only spectral features in the range observed. We discuss these criteria, useful for spectral classification of early-type stars in the GAIA spectral region, in the appendix. Using these criteria, we obtain spectral classifications, probably accurate to one subtype, for 57 objects, most of which had no previous classification or a generic classification. We identify more than 50 objects as OB supergiants. We find almost 30 luminous early-B supergiants and a number of less luminous late-O supergiants. In addition, we find a few mid B supergiants with very high luminosity, some of them displaying...

  20. BOREAS TGB-8 Starch Concentration Data Over the SSA-OBS and the SSA-OJP

    Science.gov (United States)

    Lerdau, Manuel; Hall, Forrest G. (Editor); Conrad, Sara K. (Editor)

    2000-01-01

    The BOREAS TGB-8 team collected data to investigate the controls over NMHC fluxes from boreal forest tree species. This data set includes measurements of starch concentrations in foliar samples at mature jack pine and black spruce sites. The data were collected at the OJP and OBS tower flux locations in the BOREAS SSA. These areas contained mature stands of jack pine and black spruce and were the focal sites in the BOREAS program for studies of biosphere/atmosphere exchange from these two habitat types. The OBS site is situated in a black spruce/sphagnum bog with the largest trees 155 years old and 10-15 m tall. The OJP site is in a jack pine forest, 80 to 120 years old, which lies on a sandy bench of glacial outwash with the largest tree standing 15 m tall. Temporally, the data cover the period of 24-May-1994 to 19-Sep-1994. The data are stored in tabular ASCII files.

  1. Accretion and outflow in the proplyd-like objects near Cygnus OB2

    CERN Document Server

    Guarcello, M G; Wright, N J; Garcìa-Alvarez, D; Kraemer, K E

    2014-01-01

    Cygnus OB2 is the most massive association within 2kpc from the Sun, hosting hundreds of massive stars, thousands of young low mass members, and some sights of active star formation in the surrounding cloud. Recently, 10 photoevaporating proplyd-like objects with tadpole-shaped morphology were discovered in the outskirts of the OB association, approximately 6-14pc away from its center. The classification of these objects is ambiguous, being either evaporating residuals of the parental cloud which are hosting a protostar inside, or disk-bearing stars with an evaporating disk, such as the evaporating proplyds observed in the Trapezium Cluster in Orion. In this paper we present a study based on low resolution optical spectroscopic observations made with the Optical System for Imaging and low Resolution Integrated Spectroscopy (OSIRIS), mounted on the 10.4m Gran Telescopio CANARIAS (GTC), of two of these protostars. The spectrum of one of the objects shows evidence of accretion but not of outflows. In the latter ...

  2. Magnetic field measurements and wind-line variability of OB-type stars

    CERN Document Server

    Schnerr, R S; Neiner, C; Verdugo, E; de Jong, J; Geers, V C; Wiersema, K; van Dalen, B; Tijani, A; Plaggenborg, B; Rygl, K L J

    2010-01-01

    Context. The first magnetic fields in O- and B-type stars that do not belong to the Bp-star class, have been discovered. The cyclic UV wind-line variability, which has been observed in a significant fraction of early-type stars, is likely to be related to such magnetic fields. Aims. We attempt to improve our understanding of massive-star magnetic fields, and observe twenty-five carefully-selected, OB-type stars. Methods. Of these stars we obtain 136 magnetic field strength measurements. We present the UV wind-line variability of all selected targets and summarise spectropolarimetric observations acquired using the MUSICOS spectropolarimeter, mounted at the TBL, Pic du Midi, between December 1998 and November 2004. From the average Stokes I and V line profiles, derived using the LSD method, we measure the magnetic field strengths, radial velocities, and first moment of the line profiles. Results. No significant magnetic field is detected in any OB-type star that we observed. Typical 1{\\sigma} errors are betwee...

  3. Stellar Parameters of A- and B-type Members of the Scorpius-Centaurus OB Association

    Science.gov (United States)

    Eckelkamp, Grant; Smith, Skylar; Pecaut, Mark; Mamajek, Eric E.

    2017-01-01

    Advances in high-contrast imaging and radio interferometry are allowing new avenues for circumstellar disk studies as well as direct imaging exoplanet searches. The most promising targets in these studies are intermediate mass B/A/F type members of the Scorpius-Centaurus OB association at a distance of ~100-200 pc and an age of 10-20 Myr old. However, many of the most interesting stellar members of Sco-Cen have poorly constrained stellar properties, including luminosities, distances and masses. In order to address this, we have obtained low resolution spectra from the SMARTS 1.5 m telescope and have obtained new spectral classifications for 106 stars. Using these new spectral classifications along with visual and near-infrared photometry from GAIA, Hipparcos, Tycho2, APASS and 2MASS, we obtained new reddening and extinction estimates. We then placed the stars on a Hertzsprung-Russell diagram and compared with stellar evolutionary tracks to obtain individual masses and ages. These improved stellar parameters will provide essential data for improving our understanding of high contrast imaging targets of B/A/F type members within the nearest OB association. We acknowledge support from NSF awards AST-1008908 and AST-1313029.

  4. Observations of SNR CTA 1 and the Cyg OB1 region with VERITAS

    CERN Document Server

    Aliu, Ester

    2011-01-01

    The Cygnus region is a nearby very active star forming region, containing several OB associations, considered as tracers of young pulsars. Above 12 TeV, the Milagro Collaboration has reported the discovery of a very large source, MGRO J2019+37, lying towards the Cyg OB1 association, at the edge of the Cygnus region. The young and energetic pulsar PSR J2021+3651 has been proposed to power this emission. We present here the result of deep VERITAS observations of this region at energies above 650 GeV. These observations unveil extended and complex TeV emission compatible with MGRO J2019+37, likely made of multiple sources, and a clearly separated point source emission from the direction of CTB 87, a pulsar wind nebula candidate. We will also report on the detection of TeV emission from the young Galactic SNR CTA 1, likely powered by the first pulsar discovered through its gamma-ray radiation.

  5. La binaria LSS 3074 y su entorno: ?`una nueva asociación OB?

    Science.gov (United States)

    Niemela, V.; Morrell, N.; Corti, M.

    En este trabajo presentamos un nuevo análisis orbital de LSS~3074, junto con tipos espectrales y velocidades radiales de estrellas que podrían constituir con ella una nueva asociación OB. La estrella O4f LSS3074 fue descubierta como binaria espectroscópica de corto período y líneas dobles por Morrell & Niemela (1990, ASP Conf. Ser. 7, 57). Posteriormente, Haefner et~al.(1994, IBVS 3969) encontraron variaciones fotométricas, estimando una inclinación orbital entre 50o y 55o. Teniendo en cuenta la importancia de obtener valores empíricos para las masas de estrellas O tempranas, y considerando la gran dispersión existente entre los valores observados y su discrepancia con los predichos por los modelos teóricos, hemos obtenido nuevas observaciones espectroscópicas de este sistema, con el propósito de mejorar los elementos orbitales derivados en la solución preliminar. Además, como las estrellas O tempranas suelen formar parte de cúmulos y asociaciones OB, hemos llevado a cabo una investigación espectroscópica de varias estrellas tempranas que podrían estar físicamente relacionadas con LSS~3074.

  6. Analysis of the Kinematic Structure of the Cygnus OB1 association

    CERN Document Server

    Costado, M T; Gonzalez, M; Sampedro, L

    2016-01-01

    The main objective of this study is the characterization of the velocity field in the Cygnus OB1 association using the radial velocity data currently available in the literature. This association is part of a larger star-forming complex located in the direction of the Cygnus region, but whose main subsystems may be distributed at different distances from the sun. We have collected radial velocity data for more than 300 stars in the area of 5 x 5 square degrees centred on the Cygnus OB1 association. We present the results of a kinematic clustering analysis in the subspace of the phase space formed by angular coordinates and radial velocity using two independent methodologies. We have found evidence of structure in the phase space with the detection of two main groups, corresponding to different radial velocity and distance values, belonging to the association, and associated with two main shells defined by the Halpha emission. A third grouping well separated from the other two in velocity appears to occupy the...

  7. Investigation of CygOB2 #11 (O5 Ifc) by modeling its atmosphere

    CERN Document Server

    Maryeva, Olga; Malogolovets, Eugene

    2014-01-01

    We continue the study of O-supergiants belonging to the association Cyg OB2 using moderate-resolution spectra. In this paper we present results of the modeling of the stellar atmosphere of Cyg OB2 #11. This object belongs to the spectral class Ofc, which was recently introduced and yet small in numbers. Ofc class consists of stars with normal spectra with CIII {\\lambda}{\\lambda}4647,4650,4652 emission lines of comparable intensity to those of the Of-defining lines NIII {\\lambda}{\\lambda}4634,4640,4642. We combined new spectral data obtained by the 1.5-m Russian-Turkish telescope with spectra from MAST and CASU archives and determined physical parameters of the wind and chemical composition of the stellar atmosphere using CMFGEN code. The estimated nitrogen abundance is lower than one in atmospheres of normal O-supergiants (i.e. O4-6 supergiants without additional spectral index "n" or "c") and carbon abundance is solar. Also we find an excess in silicon. We present an illustrative comparison of our modeling r...

  8. The 2.35 year itch of Cyg OB2 #9. II. Radio monitoring

    CERN Document Server

    Blomme, R; Volpi, D; De Becker, M; Prinja, R K; Pittard, J M; Parkin, E R; Absil, O

    2012-01-01

    Cyg OB2 #9 is one of a small set of non-thermal radio emitting massive O-star binaries. The non-thermal radiation is due to synchrotron emission in the colliding-wind region. Cyg OB2 #9 was only recently discovered to be a binary system and a multi-wavelength campaign was organized to study its 2011 periastron passage. We report here on the results of the radio observations obtained in this monitoring campaign. We used the Expanded Very Large Array (EVLA) radio interferometer to obtain 6 and 20 cm continuum fluxes. The observed radio light curve shows a steep drop in flux sometime before periastron. The fluxes drop to a level that is comparable to the expected free-free emission from the stellar winds, suggesting that the non-thermal emitting region is completely hidden at that time. After periastron passage, the fluxes slowly increase. We introduce a simple model to solve the radiative transfer in the stellar winds and the colliding-wind region, and thus determine the expected behaviour of the radio light cu...

  9. Near infrared diffuse interstellar bands toward the Cygnus OB2 association

    CERN Document Server

    Hamano, Satoshi; Kondo, Sohei; Sameshima, Hiroaki; Nakanishi, Kenshi; Ikeda, Yuji; Yasui, Chikako; Mizumoto, Misaki; Matsunaga, Noriyuki; Fukue, Kei; Yamamoto, Ryo; Izumi, Natsuko; Mito, Hiroyuki; Nakaoka, Tetsuya; Kawanishi, Takafumi; Kitano, Ayaka; Otsubo, Shogo; Kinoshita, Masaomi; Kawakita, Hideyo

    2016-01-01

    We obtained the near-infrared (NIR) high-resolution ($R\\equiv\\lambda/\\Delta\\lambda\\sim20,000$) spectra of the seven brightest early-type stars in the Cygnus OB2 association for investigating the environmental dependence of diffuse interstellar bands (DIBs). The WINERED spectrograph mounted on the Araki 1.3m telescope in Japan was used to collect data. All 20 of the known DIBs within the wavelength coverage of WINERED ($0.91<\\lambda<1.36\\mu$m) were clearly detected along all lines of sight because of their high flux density in the NIR wavelength range and the large extinction. The equivalent widths (EWs) of DIBs were not correlated with the column densities of C$_2$ molecules, which trace the patchy dense component, suggesting that the NIR DIB carriers are distributed mainly in the diffuse component. On the basis of the correlations among the NIR DIBs both for stars in Cyg OB2 and stars observed previously, $\\lambda\\lambda$10780, 10792, 11797, 12623, and 13175 are found to constitute a "family", in which...

  10. ObsPy: a bridge for seismology into the scientific Python ecosystem

    Science.gov (United States)

    Krischer, Lion; Megies, Tobias; Barsch, Robert; Beyreuther, Moritz; Lecocq, Thomas; Caudron, Corentin; Wassermann, Joachim

    2015-01-01

    The Python libraries NumPy and SciPy are extremely powerful tools for numerical processing and analysis well suited to a large variety of applications. We developed ObsPy (http://obspy.org), a Python library for seismology intended to facilitate the development of seismological software packages and workflows, to utilize these abilities and provide a bridge for seismology into the larger scientific Python ecosystem. Scientists in many domains who wish to convert their existing tools and applications to take advantage of a platform like the one Python provides are confronted with several hurdles such as special file formats, unknown terminology, and no suitable replacement for a non-trivial piece of software. We present an approach to implement a domain-specific time series library on top of the scientific NumPy stack. In so doing, we show a realization of an abstract internal representation of time series data permitting I/O support for a diverse collection of file formats. Then we detail the integration and repurposing of well established legacy codes, enabling them to be used in modern workflows composed in Python. Finally we present a case study on how to integrate research code into ObsPy, opening it to the broader community. While the implementations presented in this work are specific to seismology, many of the described concepts and abstractions are directly applicable to other sciences, especially to those with an emphasis on time series analysis.

  11. Accretion and outflow in the proplyd-like objects near Cygnus OB2

    Energy Technology Data Exchange (ETDEWEB)

    Guarcello, M. G. [INAF-Osservatorio Astronomico di Palermo, Piazza del Parlamento 1, I-90134 Palermo (Italy); Drake, J. J.; Wright, N. J. [Smithsonian Astrophysical Observatory, MS-67, 60 Garden Street, Cambridge, MA 02138 (United States); García-Alvarez, D. [Dpto. de Astrofísica, Universidad de La Laguna, E-38206 E-La Laguna, Tenerife (Spain); Kraemer, K. E. [Institute for Scientific Research, Boston College, Kenny Cottle L106B, Newton, MA 02459-1161 (United States)

    2014-09-20

    Cygnus OB2 is the most massive association within 2 kpc from the Sun, hosting hundreds of massive stars, thousands of young low mass members, and some sights of active star formation in the surrounding cloud. Recently, 10 photoevaporating proplyd-like objects with tadpole-shaped morphology were discovered in the outskirts of the OB association, approximately 6-14 pc away from its center. The classification of these objects is ambiguous, being either evaporating residuals of the parental cloud that are hosting a protostar inside or disk-bearing stars with an evaporating disk, such as the evaporating proplyds observed in the Trapezium Cluster in Orion. In this paper, we present a study based on low-resolution optical spectroscopic observations made with the Optical System for Imaging and low Resolution Integrated Spectroscopy, mounted on the 10.4 m Gran Telescopio CANARIAS, of two of these protostars. The spectrum of one of the objects shows evidence of accretion but not of outflows. In the latter object, the spectra show several emission lines indicating the presence of an actively accreting disk with outflow. We present estimates of the mass loss rate and the accretion rate from the disk, showing that the former exceeds the latter as observed in other known objects with evaporating disks. We also show evidence of a strong variability in the integrated flux observed in these objects as well as in the accretion and outflow diagnostics.

  12. A quantitative study of O stars in NGC2244 and the Mon OB2 association

    CERN Document Server

    Martins, F; Rauw, G; Hillier, D J

    2011-01-01

    Our goal is to determine the stellar and wind properties of seven O stars in the cluster NGC2244 and three O stars in the OB association MonOB2. These properties give us insight into the mass loss rates of O stars, allow us to check the validity of rotational mixing in massive stars, and to better understand the effects of the ionizing flux and wind mechanical energy release on the surrounding interstellar medium and its influence on triggered star formation. We collect optical and UV spectra of the target stars which are analyzed by means of atmosphere models computed with the code CMFGEN. The spectra of binary stars are disentangled and the components are studied separately. All stars have an evolutionary age less than 5 million years, with the most massive stars being among the youngest. Nitrogen surface abundances show no clear relation with projected rotational velocities. Binaries and single stars show the same range of enrichment. This is attributed to the youth and/or wide separation of the binary sys...

  13. 25 Orionis: A Kinematically Distinct 10 Myr Old Group in Orion OB1a

    CERN Document Server

    Briceño, C; Hernández, J; Calvet, N; Vivas, A K; Furesz, G; Szentgyorgyi, A; Briceno, Cesar; Hartmann, Lee; Hernandez, Jesus; Calvet, Nuria; Furesz, Gabor; Szentgyorgyi, Andrew

    2007-01-01

    We report here on the photometric and kinematic properties of a well defined group of nearly 200 low-mass pre-main sequence stars, concentrated within ~ 1 deg of the early-B star 25 Ori, in the Orion OB1a sub-association. We refer to this stellar aggregate as the 25 Orionis group. The group also harbors the Herbig Ae/Be star V346 Ori and a dozen other early type stars with photometry, parallaxes, and some with IR excess emission, consistent with group membership. The number of high and low-mass stars is in agreement with expectations from a standard Initial Mass Function. The velocity distribution for the young stars in 25 Ori shows a narrow peak centered at 19.7 km/s, very close to the velocity of the star 25 Ori. Our results provide new and compelling evidence that the 25 Ori group is a distinct kinematic entity, and that considerable space and velocity structure is present in the Ori OB1a sub-association. The low-mass members follow a well defined band in the color-magnitude diagram, consistent with an iso...

  14. Central (ICV) leptin injection increases bone formation, bone mineral density, muscle mass, serum IGF-1, and the expression of osteogenic genes in leptin-deficient ob/ob mice.

    Science.gov (United States)

    Bartell, Shoshana M; Rayalam, Srujana; Ambati, Suresh; Gaddam, Dhanunjaya R; Hartzell, Diane L; Hamrick, Mark; She, Jin-Xiong; Della-Fera, Mary Anne; Baile, Clifton A

    2011-08-01

    Both central and peripheral leptin administrations reduce body weight, food intake, and adiposity in ob/ob mice. In this study we compared effects of intracerebroventricular (ICV) and subcutaneous (SC) administration of leptin on bone metabolism in the appendicular and axial skeleton and adipose tissue gene expression and determined the effects of ICV leptin on bone marrow gene expression in ob/ob mice. In experiment 1, leptin (1.5 or 0.38 µg/d) or control was continuously injected ICV for 12 days. Gene expression analysis of femoral bone marrow stromal cells showed that expression of genes associated with osteogenesis was increased after ICV injection, whereas those associated with osteoclastogenesis, adipogenesis, and adipocyte lipid storage were decreased. In experiment 2, leptin was injected continuously ICV (0.0 or 1.5 µg/d) or SC (0.0 or 10 µg/d) for 12 days. In both experiments, regardless of mode of administration, leptin decreased body weight, food intake, and body fat and increased muscle mass, bone mineral density, bone mineral content, bone area, marrow adipocyte number, and mineral apposition rate. Serum insulin was decreased, whereas serum osteocalcin, insulin-like growth factor 1, osteoprotegerin, pyridinoline, and receptor activator of nuclear factor κB ligand concentrations were increased. In experiment 2, expression of genes in adipose tissue associated with apoptosis, lipid mobilization, insulin sensitivity, and thermogenesis was increased, whereas expression of genes associated with cell differentiation and maturation was decreased regardless of mode of administration. Thus ICV injection of leptin promotes expression of pro-osteogenic factors in bone marrow, leading to enhanced bone formation in ob/ob mice.

  15. Ocena jakości obsługi klienta w procesie kształtowania jego satysfakcji

    OpenAIRE

    2012-01-01

    Celem pracy jest analiza wybranych sposobów oceny jakości obsługi klienta w procesie kształtowania jego satysfakcji. W pracy skupiono się na istocie i zastosowaniu mystery shopping. W części teoretycznej pracy zostały przedstawione wybrane zagadnienia z zakresu marketingu usług, satysfakcji klienta, standardów obsługi klienta, a także metodologia badań satysfakcji klienta. W części praktycznej pracy znajduje się opis badania jakości obsługi klientów ING Banku Śląskiego, kt...

  16. Leptin and the obesity receptor (OB-R) in the small intestine and colon: a colocalization study

    DEFF Research Database (Denmark)

    Hansen, Gert H; Niels-Christiansen, Lise-Lotte; Danielsen, E Michael

    2008-01-01

    Leptin is a hormone that plays an important role in overall body energy homeostasis, and the obesity receptor, OB-R, is widely distributed in the organism. In the intestine, a multitude of leptin actions have been reported, but it is currently unclear to what extent the hormone affects...... the intestinal epithelial cells by an endocrine or exocrine signaling pathway. To elucidate this, the localization of endogenous porcine leptin and OB-R in enterocytes and colonocytes was studied. By immunofluorescence microscopy, both leptin and OB-R were mainly observed in the basolateral membrane...... of enterocytes and colonocytes but also in the apical microvillar membrane of the cells. By electron microscopy, coclustering of hormone and receptor in the plasma membrane and localization in endosomes was frequently detected at the basolateral surface of the epithelial cells, indicative of leptin signaling...

  17. The oligonucleotide binding (OB-fold domain of KREPA4 is essential for stable incorporation into editosomes.

    Directory of Open Access Journals (Sweden)

    Smriti Kala

    Full Text Available Most mitochondrial mRNAs in trypanosomatid parasites require uridine insertion/deletion RNA editing, a process mediated by guide RNA (gRNA and catalyzed by multi-protein complexes called editosomes. The six oligonucleotide/oligosaccharide binding (OB-fold proteins (KREPA1-A6, are a part of the common core of editosomes. They form a network of interactions among themselves as well as with the insertion and deletion sub-complexes and are essential for the stability of the editosomes. KREPA4 and KREPA6 proteins bind gRNA in vitro and are known to interact directly in yeast two-hybrid analysis. In this study, using several approaches we show a minimal interaction surface of the KREPA4 protein that is required for this interaction. By screening a series of N- and C-terminally truncated KREPA4 fragments, we show that a predicted α-helix of KREPA4 OB-fold is required for its interaction with KREPA6. An antibody against the KREPA4 α-helix or mutations of this region can eliminate association with KREPA6; while a peptide fragment corresponding to the α-helix can independently interact with KREPA6, thereby supporting the identification of KREPA4-KREPA6 interface. We also show that the predicted OB-fold of KREPA4; independent of its interaction with gRNA, is responsible for the stable integration of KREPA4 in the editosomes, and editing complexes co-purified with the tagged OB-fold can catalyze RNA editing. Therefore, we conclude that while KREPA4 interacts with KREPA6 through the α-helix region of its OB-fold, the entire OB-fold is required for its integration in the functional editosome, through additional protein-protein interactions.

  18. Ocean Basalt Simulator version 1 (OBS1): Trace element mass balance in adiabatic melting of a pyroxenite-bearing peridotite

    Science.gov (United States)

    Kimura, Jun-Ichi; Kawabata, Hiroshi

    2015-01-01

    present a new numerical trace element mass balance model for adiabatic melting of a pyroxenite-bearing peridotite for estimating mantle potential temperature, depth of melting column, and pyroxenite fraction in the source mantle for a primary ocean basalt/picrite. The Ocean Basalt Simulator version 1 (OBS1) uses a thermodynamic model of adiabatic melting of a pyroxenite-bearing peridotite with experimentally/thermodynamically parameterized liquidus-solidus intervals and source mineralogy. OBS1 can be used to calculate a sequence of adiabatic melting with two melting models, including (1) melting of peridotite and pyroxenite sources with simple mixing of their fractional melts (melt-melt mixing model), and (2) pyroxenite melting, melt metasomatism in the host peridotite, and melting of the metasomatized peridotite (source-metasomatism model). OBS1 can be used to explore (1) the fractions of peridotite and pyroxenite, (2) mantle potential temperature, (3) pressure of termination of melting, (4) degree of melting, and (5) residual mode of the sources. In order to constrain these parameters, the model calculates a mass balance for 26 incompatible trace elements in the sources and in the generated basalt/picrite. OBS1 is coded in an Excel spreadsheet and runs with VBA macros. Using OBS1, we examine the source compositions and conditions of the mid-oceanic ridge basalts, Loihi-Koolau basalts in the Hawaiian hot spot, and Jurassic Shatsky Rise and Mikabu oceanic plateau basalts and picrites. The OBS1 model shows the physical conditions, chemical mass balance, and amount of pyroxenite in the source peridotite, which are keys to global mantle recycling.

  19. Cloning and expression analysis of human reticulon 4c cDNA

    Institute of Scientific and Technical Information of China (English)

    2000-01-01

    RTNs (reticulons) is a gene family related to the growth and differentiation of neuroendocrine cell. This family is composed of several members such as RTN1, RTN2 and RTN3. RTN1 and RTN2 have been proved to have 3 transcripts with different length. Because the RTN1c cDNA was involved in the sologenesis of small cell lung carcinoma (SCLC), it was selected as a bioinformatic probe to clone novel members of RTN family with the electric hybridization assistant new-gene cloning method (EHAC). A 1677-bp cDNA was identified from human brain cDNA library. The cDNA contains an intact open reading frame (ORF) which encodes a protein of 199 amino acids. This deduced protein is highly homologous to RTN1c, RTN2c and RTN3 with identities of 64.4%, 45.8% and 50.0% respectively. This new gene was named RTN4c (GenBank accession number: AF087901). Northern hybridization showed that the full length of RTN4c transcript is about 1.8 kb. It is hardly expressed in heart, placenta, lung, spleen, thymus, testis, ovary, small intestine and peripheral blood white cells; but it is highly expressed in the tissues of skeletal muscle, brain, liver and kidney, and less expressed in the pancreas, prostate and colon. Furthermore, Northern results also showed that there is a 2.3 kb transcript expressed in 14 tissues except liver and skeletal muscle; while another 5.0 kb transcript in brain, skeletal muscle and testis. By the electric hybridization walking, we obtained two full-length contigs with a length of 4632 and 2235 bp respectively. The former encodes a protein with 1192 amino acids and was defined as RTN4a; the latter encodes another protein with 373 amino acids, and was named RTN4b. The RTN4 gene was mapped to human chromosome 2p14-p13 region by the radiation hybridization (RH).

  20. VizieR Online Data Catalog: Cep OB2 Herschel/PACS view (Sicilia-Aguilar+, 2015)

    Science.gov (United States)

    Sicilia-Aguilar, A.; Roccatagliata, V.; Getman, K.; Riviere-Marichalar, P.; Birnstiel, T.; Merin, B.; Fang, M.; Henning, T.; Eiroa, C.; Currie, T.

    2015-02-01

    The Cep OB2 clusters, Tr 37 (centered at 21:38:09, +57:26:48, J2000) and NGC 7160 (centered at 21:53:40, 62:36:10, J2000), were observed with the ESA Herschel Space Observatory using the Photodetector Array Camera and Spectrometer (PACS), as part of the open time (OT) program "Disk dispersal in Cep OB2" (PI A. Sicilia-Aguilar). We obtained a total of 23h observing time in parallel mode at 70 and 160um. Observations took place between November 2012 and January 2013. (4 data files).

  1. Processing and characterization of B4C/Cu graded composite as plasma facing component for fusion reactors

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    A new approach for fabricating B4C/Cu graded composite by rapid self-resistance sintering under ultra-high pressure was presented, by which a near dense B4C/Cu graded composite with a compositional spectrum of 0-100% was successfully fabricated. Plasma relevant performances ofsintered B4C/Cu composite were preliminarily characterized, it is found that its chemical sputtering yield is 70% lower than that of SMF800 nuclear graphite under 2.7 keV D+ irradiation, and almost no damages after 66 shots of in situ plasma discharge in HL-1 Tokamak facility, which indicates B4C/Cu plasma facing component has a good physical and chemical sputtering resistance performance compared with nuclear graphite.

  2. Electronic structure and electrical transport characteristics of C60, 2C60 and 4C60 fullerene molecules

    Institute of Scientific and Technical Information of China (English)

    SHEN Haijun; MU Xiancai

    2007-01-01

    The extended Hückel method and the Green's function method were used to calculate the electronic struc-ture and electrical transport of Au electrode-C60,2C60 or 4C60 fullerene-Au electrode systems.Furthermore,their electronic structure and electrical transport characteristics were com-pared and analyzed.The results show that (I) owing to the contact with the Au electrodes,the C60,2C60 and 4C60 mole-cules change in their electronic structures ignificantly,and their energy gaps between LUMO and HOMO are narrow;(ii) the bonding between C60,2C60 or 4C60 fullerene and Au electrodes is partially covalent and partially electrovalent;and (iii) the conductance of the three fullerenes conforms to the order of C60>2C60>4C60.

  3. Kinetic Behavior of LiFePO4/C Thin Film Cathode Material for Lithium-Ion Batteries

    OpenAIRE

    Kucinskis, G; Bajārs, G; Kleperis, J.; Smits, J.

    2010-01-01

    LiFePO4 was prepared in a solid state synthesis with various levels of carbon content. LiFePO4/C thin films were obtained via magnetron sputtering. The surface morphology and structure was examined. Electrochemical properties of LiFePO4/C were studied, by using cyclic voltammetry, chronopotentiometry and electrochemical impedance spectroscopy. Thin films acquired show a potential use as a cathode in lithium ion batteries, displaying charge capacity up to 34 mAh g-1.

  4. A simulation of a pebble bed reactor core by the MCNP-4C computer code

    Directory of Open Access Journals (Sweden)

    Bakhshayesh Moshkbar Khalil

    2009-01-01

    Full Text Available Lack of energy is a major crisis of our century; the irregular increase of fossil fuel costs has forced us to search for novel, cheaper, and safer sources of energy. Pebble bed reactors - an advanced new generation of reactors with specific advantages in safety and cost - might turn out to be the desired candidate for the role. The calculation of the critical height of a pebble bed reactor at room temperature, while using the MCNP-4C computer code, is the main goal of this paper. In order to reduce the MCNP computing time compared to the previously proposed schemes, we have devised a new simulation scheme. Different arrangements of kernels in fuel pebble simulations were investigated and the best arrangement to decrease the MCNP execution time (while keeping the accuracy of the results, chosen. The neutron flux distribution and control rods worth, as well as their shadowing effects, have also been considered in this paper. All calculations done for the HTR-10 reactor core are in good agreement with experimental results.

  5. Investigation of defects in sputtered W/B{sub 4}C multilayers

    Energy Technology Data Exchange (ETDEWEB)

    Jiang, Hui, E-mail: jianghui@sinap.ac.cn [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Zhangheng Road 239, Pudong District, Shanghai 201204 (China); Yan, Shuai [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Zhangheng Road 239, Pudong District, Shanghai 201204 (China); Zhu, Jingtao [Key Laboratory of Advanced Microstructure Materials, Ministry of Education, Institute of Precision Optical Engineering, Tongji University, Shanghai 200092 (China); Dong, Zhaohui; Zheng, Yi; He, Yumei; Li, Aiguo [Shanghai Synchrotron Radiation Facility, Shanghai Institute of Applied Physics, Chinese Academy of Sciences, Zhangheng Road 239, Pudong District, Shanghai 201204 (China)

    2015-12-01

    Highlights: • Three sputtered multilayer samples were stored into a dry cabinet for four months. • It was revealed that serious oxidation existed in interior layers for the multilayer with the surface turning white. • The bands at ∼689 and ∼802 cm{sup −1} appearing at the blister, pit or buckling defects can be interpreted as W-O stretching modes. • The oxide-induced microvoids led to strong oxidation, expanded volume and produced compressive stress. • The spot reflected from the multilayer with serious buckling defects had more intensity fluctuation and became narrow. - Abstract: Sputtered W/B{sub 4}C multilayers were determined by X-ray photoelectron spectroscopy, Raman scattering spectroscopy, scanning electron microscopy and atomic force microscopy synthetically. Two defect modes were observed in multilayers: buckle delamination and oxidation. This paper compares the chemical composition varies along multilayer depth and at different regions and tries to interpret the mechanism of defect evolution. The X-ray grazing incidence reflection profiles were compared to the theoretical value to estimate the influences from different defects.

  6. The peculiar radio galaxy 4C 35.06: a case for recurrent AGN activity?

    CERN Document Server

    Shulevski, A; Barthel, P D; Murgia, M; van Weeren, R J; White, G J; Brüggen, M; Kunert-Bajraszewska, M; Jamrozy, M; Best, P N; Röttgering, H J A; Chyzy, K T; de Gasperin, F; Bîrzan, L; Brunetti, G; Brienza, M; Rafferty, D A; Anderson, J; Beck, R; Deller, A; Zarka, P; Schwarz, D; Mahony, E; Orrú, E; Bell, M E; Bentum, M J; Bernardi, G; Bonafede, A; Breitling, F; Broderick, J W; Butcher, H R; Carbone, D; Ciardi, B; de Geus, E; Duscha, S; Eislöffel, J; Engels, D; Falcke, H; Fallows, R A; Fender, R; Ferrari, C; Frieswijk, W; Garrett, M A; Grießmeier, J; Gunst, A W; Heald, G; Hoeft, M; Hörandel, J; Horneffer, A; van der Horst, A J; Intema, H; Juette, E; Karastergiou, A; Kondratiev, V I; Kramer, M; Kuniyoshi, M; Kuper, G; Maat, P; Mann, G; McFadden, R; McKay-Bukowski, D; McKean, J P; Meulman, H; Mulcahy, D D; Munk, H; Norden, M J; Paas, H; Pandey-Pommier, M; Pizzo, R; Polatidis, A G; Reich, W; Rowlinson, A; Scaife, A M M; Serylak, M; Sluman, J; Smirnov, O; Steinmetz, M; Swinbank, J; Tagger, M; Tang, Y; Tasse, C; Thoudam, S; Toribio, M C; Vermeulen, R; Vocks, C; Wijers, R A M J; Wise, M W; Wucknitz, O

    2015-01-01

    Using observations obtained with the LOw Fequency ARray (LOFAR), the Westerbork Synthesis Radio Telescope (WSRT) and archival Very Large Array (VLA) data, we have traced the radio emission to large scales in the complex source 4C 35.06 located in the core of the galaxy cluster Abell 407. At higher spatial resolution (~4"), the source was known to have two inner radio lobes spanning 31 kpc and a diffuse, low-brightness extension running parallel to them, offset by about 11 kpc (in projection). At 62 MHz, we detect the radio emission of this structure extending out to 210 kpc. At 1.4 GHz and intermediate spatial resolution (~30"), the structure appears to have a helical morphology. We have derived the characteristics of the radio spectral index across the source. We show that the source morphology is most likely the result of at least two episodes of AGN activity separated by a dormant period of around 35 Myr. The AGN is hosted by one of the galaxies located in the cluster core of Abell 407. We propose that it ...

  7. Intermittent Jet Activity in the Radio Galaxy 4C29.30?

    Energy Technology Data Exchange (ETDEWEB)

    Jamrozy, M.; /Jagiellonian U., Astron. Observ.; Konar, C.; Saikia, D.J.; /NCRA, Ganeshkhind; Stawarz, L.; /Jagiellonian U., Astron. Observ. /KIPAC, Menlo Park /SLAC; Mack,; /Bologna, Ist. Radioastronomia; Siemiginowska, A.; /Harvard-Smithsonian Ctr. Astrophys.

    2007-04-02

    We present radio observations at frequencies ranging from 240 to 8460 MHz of the radio galaxy 4C29.30 (J0840+2949) using the Giant Metrewave Radio Telescope (GMRT), the Very Large Array (VLA) and the Effelsberg telescope. We report the existence of weak extended emission with an angular size of {approx} 520 arcsec (639 kpc) within which a compact edge-brightened double-lobed source with a size of 29 arcsec (36 kpc) is embedded. We determine the spectrum of the inner double from 240 to 8460 MHz and show that it has a single power-law spectrum with a spectral index is {approx} 0.8. Its spectral age is estimated to be 33 Myr. The extended diffuse emission has a steep spectrum with a spectral index of {approx} 1.3 and a break frequency 240 MHz. The spectral age is {approx}>200 Myr, suggesting that the extended diffuse emission is due to an earlier cycle of activity. We reanalyze archival x-ray data from Chandra and suggest that the x-ray emission from the hotspots consists of a mixture of nonthermal and thermal components, the latter being possibly due to gas which is shock heated by the jets from the host galaxy.

  8. The unfriendly ISM in the radio galaxy 4C12.50 (PKS 1345+12)

    CERN Document Server

    Morganti, R

    2004-01-01

    The radio source 4C12.50 has often been suggested to be a prime candidate for the link between ultraluminous infrared galaxies and young radio galaxies. A VLBI study of the neutral hydrogen in the nuclear regions of this object shows that most of the gas detected close to the systemic velocity is associated with an off-nuclear cloud (~50 to 100 pc from the radio core) with a column density of ~10^22 T_spin/100 K) cm^(-2) and an HI mass of a few times 10^5 to 10^6 M_sun. We consider a number of possibilities to explain the results. In particular, we discus the possibility that this cloud indicates the presence of a rich and clumpy interstellar medium in the centre, likely left over from the merger that triggered the activity and that this medium influences the growth of the radio source. The location of the cloud -- at the edge of the northern radio jet/lobe -- suggests that the radio jet might be interacting with a gas cloud. This interaction could be responsible for bending the young radio jet. The velocity ...

  9. Performance of the MTR core with MOX fuel using the MCNP4C2 code.

    Science.gov (United States)

    Shaaban, Ismail; Albarhoum, Mohamad

    2016-08-01

    The MCNP4C2 code was used to simulate the MTR-22 MW research reactor and perform the neutronic analysis for a new fuel namely: a MOX (U3O8&PuO2) fuel dispersed in an Al matrix for One Neutronic Trap (ONT) and Three Neutronic Traps (TNTs) in its core. Its new characteristics were compared to its original characteristics based on the U3O8-Al fuel. Experimental data for the neutronic parameters including criticality relative to the MTR-22 MW reactor for the original U3O8-Al fuel at nominal power were used to validate the calculated values and were found acceptable. The achieved results seem to confirm that the use of MOX fuel in the MTR-22 MW will not degrade the safe operational conditions of the reactor. In addition, the use of MOX fuel in the MTR-22 MW core leads to reduce the uranium fuel enrichment with (235)U and the amount of loaded (235)U in the core by about 34.84% and 15.21% for the ONT and TNTs cases, respectively.

  10. High energy properties of the flat spectrum radio quasar 4C 50.11

    CERN Document Server

    Zhou, Jianeng; Liang, Chen; Wang, Zhongxiang

    2016-01-01

    We investigate the $\\gamma$-ray and X-ray properties of the flat spectrum radio quasar (FSRQ) \\4c50 at redshift $z= 1.517$. The {\\it Fermi} Large Area Telescope (LAT) data indicate that this source was in an active state since 2013 July. During the active period, the $\\gamma$-ray flux increased by more than a factor of three and two distinct flares were detected with the variability timescale as short as several hours. The $\\gamma$-ray spectra can be well fitted by a log-parabola. From the fitting, we find a correlation between the peak energy and spectral curvature for the $\\gamma$-ray spectra, which is the first time seen in $\\gamma$-ray emission from a blazar. The {\\it Swift} X-ray Telescope (XRT) data show that the source was variable at X-ray energies, but no evidence shows flux or spectral changes related to the $\\gamma$-ray activity. The broad-band X-ray spectrum obtained with {\\it Swift} XRT and {\\it NuSTAR} is well described by a broken PL model, with an extremely hard spectrum ($\\Gamma_{1} \\sim 0.1$...

  11. REVERSIBLE HYDROGEN STORAGE IN A LiBH{sub 4}-C{sub 60} NANOCOMPOSITE

    Energy Technology Data Exchange (ETDEWEB)

    Teprovich, J.; Zidan, R.; Peters, B.; Wheeler, J.

    2013-08-06

    Reversible hydrogen storage in a LiBH{sub 4}:C{sub 60} nanocomposite (70:30 wt. %) synthesized by solvent-assisted mixing has been demonstrated. During the solvent-assisted mixing and nanocomposite formation, a chemical reaction occurs in which the C{sub 60} cages are significantly modified by polymerization as well as by hydrogenation (fullerane formation) in the presence of LiBH{sub 4}. We have determined that two distinct hydrogen desorption events are observed upon rehydrogenation of the material, which are attributed to the reversible formation of a fullerane (C{sub 60}H{sub x}) as well as a LiBH4 species. This system is unique in that the carbon species (C{sub 60}) actively participates in the hydrogen storage process which differs from the common practice of melt infiltration of high surface area carbon materials with LiBH{sub 4} (nanoconfinment effect). This nanocomposite demonstrated good reversible hydrogen storage properties as well as the ability to absorb hydrogen under mild conditions (pressures as low as 10 bar H{sub 2} or temperatures as low as 150°C). The nanocomposite was characterized by TGA-RGA, DSC, XRD, LDI-TOF-MS, FTIR, 1H NMR, and APPI MS.

  12. The warm absorber in the radio-loud quasar 4C +74.26

    CERN Document Server

    Di Gesu, L

    2016-01-01

    Outflows of photoionized gas are commonly detected in the X-ray spectra of Seyfert 1 galaxies. However, the evidence for this phenomenon in broad line radio galaxies, which are analogous to Seyfert 1 galaxies in the radio-loud regime, has so far been scarce. Here, we present the analysis of the X-ray absorption in the radio-loud quasar 4C +74.26. With the aim of characterizing the kinetic and the ionization conditions of the absorbing material, we fitted jointly the XMM-Newton Reflection Grating Spectrometer (RGS) and the Chandra High Energy Transmission Grating Spectrometer (HETGS) spectra, which were taken 4 months apart. The intrinsic continuum flux did not vary significantly during this time lapse. The spectrum shows the absorption signatures (e.g., Fe-UTA, \\ion{O}{vii}, and \\ion{Ne}{vii}--\\ion{Ne}{x}) of a photoionized gas outflow ($N_{\\rm H} \\sim 3.5 \\times 10^{21} \\rm cm^{-2}$, $\\log \\xi \\sim 2.6$, $v_{\\rm out}\\sim 3600 \\, \\rm km \\, s^{-1}$) located at the redshift of source. We estimate that the gas i...

  13. Microstructure and Dry-Sliding Wear Behavior of B4C Ceramic Particulate Reinforced Al 5083 Matrix Composite

    Directory of Open Access Journals (Sweden)

    Qian Zhao

    2016-09-01

    Full Text Available B4C ceramic particulate–reinforced Al 5083 matrix composite with various B4C content was fabricated successfully via hot-press sintering under Argon atmosphere. B4C particles presented relative high wettability, bonding strength and symmetrical distribution in the Al 5083 matrix. The hardness value, friction coefficient and wear resistance of the composite were higher than those of the Al 5083 matrix. The augment of the B4C content resulted in the increase of the friction coefficient and decrease of the wear mass loss, respectively. The 30 wt % B4C/Al 5083 composite exhibited the highest wear resistance. At a low load of 50 N, the dominant wear mechanisms of the B4C/Al 5083 composite were micro-cutting and abrasive wear. At a high load of 200 N, the dominant wear mechanisms were micro-cutting and adhesion wear associated with the formation of the delamination layer which protected the composite from further wear and enhanced the wear resistance under the condition of high load.

  14. A formation scenario of young stellar groups in the region of the Scorpio Centaurus OB association

    CERN Document Server

    Ortega, V G; De la Reza, R; Bazzanella, B

    2009-01-01

    The main objective of this work is to investigate the role played by Lower Centaurus Crux (LCC) and Upper Centaurus Lupus (UCL), both subcomponents of the Scorpio Centaurus OB association (Sco-Cen), in the formation of the groups beta Pictoris, TW Hydrae and the eta Chamaeleontis cluster. The dynamical evolution of all the stellar groups involved and of the bubbles and shells blown by LCC and UCL are calculated and followed from the past to the present. This leads to a formation scenario in which (1) the groups beta Pictoris, TW Hydrae were formed in the wake of the shells created by LCC and UCL, (2) the young cluster eta Chamaeleontis was born as a consequence of the collision of the shells of LCC and UCL, and (3) the formation of Upper Scorpius (US), the other main subcomponent of the Sco-Cen association, may have been started by the same process that created eta Chamaeleontis.

  15. ACCURATE QUANTITATIVE SPECTROSCOPY OF OB STARS: C AND N ABUNDANCES NEAR THE MAIN SEQUENCE

    Directory of Open Access Journals (Sweden)

    M. F. Nieva

    2008-01-01

    Full Text Available We present a state-of-the-art analysis technique able to simultaneously reproduce the entire H and He spectra of OB-type stars in the visual and the near-IR and to derive highly accurate metal abundances (so far C and N. The spectrum synthesis relies on a hybrid non-LTE approach involving our most recent model atoms. Accurate atmospheric parameters, practically free of systematic errors, are derived spectroscopically (from Stark-broadened H lines and ionization equilibria of He i/ii and Cii-iv for a sample of randomly distributed stars in the solar vicinity. Highly consistent abundances are found in contrast to previous reports indicating broad scatter and large uncertainties. The improvements result from avoidance of systematic errors in the parameter determination, which may be larger than expected in previous work, and a critical evaluation of atomic data for the model atom construction

  16. Distributed Reservation Protocol and QoS Method in WR-OBS System

    Institute of Scientific and Technical Information of China (English)

    LAN Zhou; GUO Hong-xiang; WU Jian; LIN Jin-tong

    2005-01-01

    Starting from centralized control model used in wavelength routed optical burst switching network, a distributed control model and correspondent wavelength resource reservation protocol are proposed in this paper. Two Quality-of-Service (QoS) methods, Based on the resource reservation protocol, are discussed. Also, computer simulation is implemented to investigate the performance of the newly proposed reservation protocol and QoS methods. Simulation results demonstrate that the QoS methods can efficiently provide different level service quality to traffic with different priorities. Furthermore, performances of the two QoS methods are compared concerning the QoS distinguished level, burst lost probability and implementation difficulty. It has been shown that the newly propose reservation protocol and QoS methods is a high qualified candidate for the future OBS networks.

  17. Distribution of global fallouts cesium-137 in taiga and tundra catenae at the Ob River basin

    Science.gov (United States)

    Semenkov, I. N.; Usacheva, A. A.; Miroshnikov, A. Yu.

    2015-03-01

    The classification of soil catenae at the Ob River basin is developed and applied. This classification reflects the diverse geochemical conditions that led to the formation of certain soil bodies, their combinations and the migration fields of chemical elements. The soil and geochemical diversity of the Ob River basin catenae was analyzed. The vertical and lateral distribution of global fallouts cesium-137 was studied using the example of the four most common catenae types in Western Siberia tundra and taiga. In landscapes of dwarf birches and dark coniferous forests on gleysols, cryosols, podzols, and cryic-stagnosols, the highest 137Cs activity density and specific activity are characteristic of the upper soil layer of over 30% ash, while the moss-grass-shrub cover is characterized by low 137Cs activity density and specific activity. In landscapes of dwarf birches and pine woods on podzols, the maximum specific activity of cesium-137 is typical for moss-grass-shrub cover, while the maximum reserves are concentrated in the upper soil layer of over 30% ash. Bog landscapes and moss-grass-shrub cover are characterized by a minimum activity of 137Cs, and its reserves in soil generally decrease exponentially with depth. The cesium-137 penetration depth increases in oligotrophic histosols from northern to middle taiga landscapes from 10-15 to 40 cm. 137Cs is accumulated in oligotrophic histosols for increases in pH from 3.3 to 4.0 and in concretionary interlayers of pisoplinthic-cryic-histic-stagnosols. Cryogenic movement, on the one hand, leads to burying organic layers enriched in 137Cs and, on the other hand, to deducing specific activity when mixed with low-active material from lower soil layers.

  18. Stagnant Shells in the Vicinity of the Dusty Wolf–Rayet–OB Binary WR 112

    Science.gov (United States)

    Lau, R. M.; Hankins, M. J.; Schödel, R.; Sanchez-Bermudez, J.; Moffat, A. F. J.; Ressler, M. E.

    2017-02-01

    We present high spatial resolution mid-infrared images of the nebula around the late-type carbon-rich Wolf–Rayet (WC)–OB binary system WR 112 taken by the recently upgraded VLT spectrometer and imager for the mid-infrared (VISIR) with the PAH1, Ne ii_2, and Q3 filters. The observations reveal a morphology resembling a series of arc-like filaments and broken shells. Dust temperatures and masses are derived for each of the identified filamentary structures, which exhibit temperatures ranging from {179}-6+8 K at the exterior W2 filament to {355}-25+37 K in the central 3″. The total dust mass summed over the features is 2.6 ± 0.4 × 10‑5 M⊙. A multi-epoch analysis of mid-IR photometry of WR 112 over the past ∼20 years reveals no significant variability in the observed dust temperature and mass. The morphology of the mid-IR dust emission from WR 112 also exhibits no significant expansion from imaging data taken in 2001, 2007, and 2016, which disputes the current interpretation of the nebula as a high expansion velocity (∼1200 km s‑1) “pinwheel”-shaped outflow driven by the central WC–OB colliding-wind binary. An upper limit of ≲120 km s‑1 is derived for the expansion velocity assuming a distance of 4.15 kpc. The upper limit on the average total mass-loss rate from the central 3″ of WR 112 is estimated to be ≲8 × 10‑6 M⊙ year‑1. We leave its true nature as an open question, but propose that the WR 112 nebula may have formed in the outflow during a previous red or yellow supergiant phase of the central Wolf–Rayet star.

  19. STN1 OB Fold Mutation Alters DNA Binding and Affects Selective Aspects of CST Function

    Science.gov (United States)

    Bhattacharjee, Anukana; Stewart, Jason; Chaiken, Mary; Price, Carolyn M.

    2016-01-01

    Mammalian CST (CTC1-STN1-TEN1) participates in multiple aspects of telomere replication and genome-wide recovery from replication stress. CST resembles Replication Protein A (RPA) in that it binds ssDNA and STN1 and TEN1 are structurally similar to RPA2 and RPA3. Conservation between CTC1 and RPA1 is less apparent. Currently the mechanism underlying CST action is largely unknown. Here we address CST mechanism by using a DNA-binding mutant, (STN1 OB-fold mutant, STN1-OBM) to examine the relationship between DNA binding and CST function. In vivo, STN1-OBM affects resolution of endogenous replication stress and telomere duplex replication but telomeric C-strand fill-in and new origin firing after exogenous replication stress are unaffected. These selective effects indicate mechanistic differences in CST action during resolution of different replication problems. In vitro binding studies show that STN1 directly engages both short and long ssDNA oligonucleotides, however STN1-OBM preferentially destabilizes binding to short substrates. The finding that STN1-OBM affects binding to only certain substrates starts to explain the in vivo separation of function observed in STN1-OBM expressing cells. CST is expected to engage DNA substrates of varied length and structure as it acts to resolve different replication problems. Since STN1-OBM will alter CST binding to only some of these substrates, the mutant should affect resolution of only a subset of replication problems, as was observed in the STN1-OBM cells. The in vitro studies also provide insight into CST binding mechanism. Like RPA, CST likely contacts DNA via multiple OB folds. However, the importance of STN1 for binding short substrates indicates differences in the architecture of CST and RPA DNA-protein complexes. Based on our results, we propose a dynamic DNA binding model that provides a general mechanism for CST action at diverse forms of replication stress. PMID:27690379

  20. The warm absorber in the radio-loud quasar 4C +74.26

    Science.gov (United States)

    Di Gesu, L.; Costantini, E.

    2016-10-01

    Outflows of photoionized gas are commonly detected in the X-ray spectra of Seyfert 1 galaxies. However, the evidence for this phenomenon in broad line radio galaxies, which are analogous to Seyfert 1 galaxies in the radio-loud regime, has so far been scarce. Here, we present the analysis of the X-ray absorption in the radio-loud quasar 4C +74.26. With the aim of characterizing the kinetic and the ionization conditions of the absorbing material, we fitted jointly the XMM-Newton Reflection Grating Spectrometer (RGS) and the Chandra High Energy Transmission Grating Spectrometer (HETGS) spectra, which were taken 4 months apart. The intrinsic continuum flux did not vary significantly during this time lapse. The spectrum shows the absorption signatures (e.g., Fe-UTA, O vii, and Ne vii-Ne x) of a photoionized gas outflow (NH ~ 3.5 × 1021 cm-2, log ξ ~ 2.6, vout ~ 3600 km s-1) located at the redshift of source. We estimate that the gas is located outside the broad line region but within the boundaries of the putative torus. This ionized absorber is consistent with the X-ray counterpart of a polar scattering outflow reported in the optical band for this source. The kinetic luminosity carried by the outflow is insufficient to produce a significant feedback is this quasar. Finally, we show that the heavy soft X-ray absorption that was noticed in the past for this source arises mostly in the Galactic interstellar medium.

  1. 4C code analysis of thermal-hydraulic transients in the KSTAR PF1 superconducting coil

    Science.gov (United States)

    Savoldi Richard, L.; Bonifetto, R.; Chu, Y.; Kholia, A.; Park, S. H.; Lee, H. J.; Zanino, R.

    2013-01-01

    The KSTAR tokamak, in operation since 2008 at the National Fusion Research Institute in Korea, is equipped with a full superconducting magnet system including the central solenoid (CS), which is made of four symmetric pairs of coils PF1L/U-PF4L/U. Each of the CS coils is pancake wound using Nb3Sn cable-in-conduit conductors with a square Incoloy jacket. The coils are cooled with supercritical He in forced circulation at nominal 4.5 K and 5.5 bar inlet conditions. During different test campaigns the measured temperature increase due to AC losses turned out to be higher than expected, which motivates the present study. The 4C code, already validated against and applied to different types of thermal-hydraulic transients in different superconducting coils, is applied here to the thermal-hydraulic analysis of a full set of trapezoidal current pulses in the PF1 coils, with different ramp rates. We find the value of the coupling time constant nτ that best fits, at each current ramp rate, the temperature increase up to the end of the heating at the coil outlet. The agreement between computed results and the whole set of measured data, including temperatures, pressures and mass flow rates, is then shown to be very good both at the inlet and at the outlet of the coil. The nτ values needed to explain the experimental results decrease at increasing current ramp rates, consistently with the results found in the literature.

  2. A Facile Route for Synthesis of LiFePO4/C Cathode Material with Nano-sized Primary Particles

    Institute of Scientific and Technical Information of China (English)

    肖政伟; 胡国荣; 杜柯; 彭忠东

    2014-01-01

    A facile and practical route was introduced to prepare LiFePO4/C cathode material with nano-sized primary particles and excellent electrochemical performance. LiH2PO4 was synthesized by using H3PO4 and LiOH as raw materials. Then, as-prepared LiH2PO4, reduced iron powder andα-D-glucose were ball-milled, dried and sin-tered to prepare LiFePO4/C. X-ray diffractometry was used to characterize LiH2PO4, ball-milled product and LiFePO4/C. Differential scanning calorimeter-thermo gravimetric analysis was applied to investigate possible reac-tions in sintering and find suitable temperature for LiFePO4 formation. Scanning electron microscopy was em-ployed for the morphology of LiFePO4/C. As-prepared LiH2PO4 is characterized to be in P21cn(33) space group, which reacts with reduced iron powder to form Li3PO4, Fe3(PO4)2 and H2 in ball-milling and sintering. The appro-priate temperature for LiFePO4/C synthesis is 541.3-976.7 °C. LiFePO4/C prepared at 700 °C presents nano-sized primary particles forming aggregates. Charge-discharge examination indicates that as-prepared LiFePO4/C displays appreciable discharge capacities of 145 and 131 mA·h·g-1 at 0.1 and 1 C respectively and excellent discharge ca-pacity retention.

  3. Obésité: aube hésitée, et quoi pour moi demain

    OpenAIRE

    Battisti, Oreste

    2006-01-01

    cette journée aborde le cocnept familial, l'aspect communautaire, l'épidémiologie, l'aspect nutritionnel, l'aspect somatique et l'aspect psychologique de l'obésité de l'enfant dans le cadre familial. Peer reviewed

  4. Crystal Structures of RMI1 and RMI2, Two OB-Fold Regulatory Subunits of the BLM Complex

    Energy Technology Data Exchange (ETDEWEB)

    Wang, Feng; Yang, Yuting; Singh, Thiyam Ramsing; Busygina, Valeria; Guo, Rong; Wan, Ke; Wang, Weidong; Sung, Patrick; Meetei, Amom Ruhikanta; Lei, Ming (Yale-MED); (NIH); (Michigan-Med); (UCIN-MED)

    2010-11-05

    Mutations in BLM, a RecQ-like helicase, are linked to the autosomal recessive cancer-prone disorder Bloom's syndrome. BLM associates with topoisomerase (Topo) III{alpha}, RMI1, and RMI2 to form the BLM complex that is essential for genome stability. The RMI1-RMI2 heterodimer stimulates the dissolution of double Holliday junction into non-crossover recombinants mediated by BLM-Topo III{alpha} and is essential for stabilizing the BLM complex. However, the molecular basis of these functions of RMI1 and RMI2 remains unclear. Here we report the crystal structures of multiple domains of RMI1-RMI2, providing direct confirmation of the existence of three oligonucleotide/oligosaccharide binding (OB)-folds in RMI1-RMI2. Our structural and biochemical analyses revealed an unexpected insertion motif in RMI1N-OB, which is important for stimulating the dHJ dissolution. We also revealed the structural basis of the interaction between RMI1C-OB and RMI2-OB and demonstrated the functional importance of the RMI1-RMI2 interaction in genome stability maintenance.

  5. Structure-guided mutational analysis of the OB, HhH, and BRCT domains of Escherichia coli DNA ligase.

    Science.gov (United States)

    Wang, Li Kai; Nair, Pravin A; Shuman, Stewart

    2008-08-22

    NAD(+)-dependent DNA ligases (LigAs) are ubiquitous in bacteria and essential for growth. LigA enzymes have a modular structure in which a central catalytic core composed of nucleotidyltransferase and oligonucleotide-binding (OB) domains is linked via a tetracysteine zinc finger to distal helix-hairpin-helix (HhH) and BRCT (BRCA1-like C-terminal) domains. The OB and HhH domains contribute prominently to the protein clamp formed by LigA around nicked duplex DNA. Here we conducted a structure-function analysis of the OB and HhH domains of Escherichia coli LigA by alanine scanning and conservative substitutions, entailing 43 mutations at 22 amino acids. We thereby identified essential functional groups in the OB domain that engage the DNA phosphodiester backbone flanking the nick (Arg(333)); penetrate the minor grove and distort the nick (Val(383) and Ile(384)); or stabilize the OB fold (Arg(379)). The essential constituents of the HhH domain include: four glycines (Gly(455), Gly(489), Gly(521), Gly(553)), which bind the phosphate backbone across the minor groove at the outer margins of the LigA-DNA interface; Arg(487), which penetrates the minor groove at the outer margin on the 3 (R)-OH side of the nick; and Arg(446), which promotes protein clamp formation via contacts to the nucleotidyltransferase domain. We find that the BRCT domain is required in its entirety for effective nick sealing and AMP-dependent supercoil relaxation.

  6. Facile synthesis of Fe3O4@C hollow nanospheres and their application in polluted water treatment

    Science.gov (United States)

    Zhang, Yuanguang; Xu, Shihao; Xia, Hongyu; Zheng, Fangcai

    2016-11-01

    Nanostructured carbon-based materials, such as carbon nanotube arrays have shown respectable removal ability for heavy metal ions and organic dyes in aqueous solution. Although the carbon-based materials exhibited excellent removal ability, the separation of them from the aqueous solution is difficult and time-consuming. Here we demonstrated a novel and facile route for the large-scale fabrication of Fe3O4@C hollow nanospheres, with using ferrocene as a single reagent and SiO2 as a template. The as-prepared Fe3O4@C hollow nanospheres exhibited adsorption ability for heavy metal ions and organic dyes from aqueous solution, and can be easily separated by an external magnet. When the as-prepared Fe3O4@C hollow nanospheres were mixed with the aqueous solution of Hg2+ within 15 min, the removal efficiency was 90.3%. The as-prepared Fe3O4@C hollow nanospheres were also exhibited a high adsorption capacity (100%) as the adsorbent for methylene blue (MB). In addition, the as-prepared Fe3O4@C hollow nanospheres can be used as the recyclable sorbent for water treatment via a simple magnetic separation.

  7. g4c2c: A Model for Citizen Engagement at Arms’ Length from Government

    Directory of Open Access Journals (Sweden)

    Axel Bruns

    2011-03-01

    Full Text Available Normal 0 false false false EN-AU X-NONE X-NONE MicrosoftInternetExplorer4 /* Style Definitions */ table.MsoNormalTable {mso-style-name:"Table Normal"; mso-tstyle-rowband-size:0; mso-tstyle-colband-size:0; mso-style-noshow:yes; mso-style-priority:99; mso-style-qformat:yes; mso-style-parent:""; mso-padding-alt:0cm 5.4pt 0cm 5.4pt; mso-para-margin:0cm; mso-para-margin-bottom:.0001pt; mso-pagination:widow-orphan; font-size:11.0pt; font-family:"Calibri","sans-serif"; mso-ascii-font-family:Calibri; mso-ascii-theme-font:minor-latin; mso-fareast-font-family:"Times New Roman"; mso-fareast-theme-font:minor-fareast; mso-hansi-font-family:Calibri; mso-hansi-theme-font:minor-latin; mso-bidi-font-family:"Times New Roman"; mso-bidi-theme-font:minor-bidi;} The recognition that Web 2.0 applications and social media sites will strengthen and improve interaction between governments and citizens has resulted in a global push into new e-democracy or Government 2.0 spaces. These typically follow government-to-citizen (g2c or citizen-to-citizen (c2c models, but both these approaches are problematic: g2c is often concerned more with service delivery to citizens as clients, or exists to make a show of ‘listening to the public’ rather than to genuinely source citizen ideas for government policy, while c2c often takes place without direct government participation and therefore cannot ensure that the outcomes of citizen deliberations are accepted into the government policy-making process. Building on recent examples of Australian Government 2.0 initiatives, we suggest a new approach based on government support for citizen-to-citizen engagement, or g4c2c, as a workable compromise, and suggest that public service broadcasters should play a key role in facilitating this model of citizen engagement.

  8. Phase Constitution in Mixed Gd2O3 and B4C by Sintering at High Temperature

    Institute of Scientific and Technical Information of China (English)

    Wu Wenyuan; Xu Jingyu; Bian Xue; Hu Guangyong; Sun Shuchen; Tu Ganfeng

    2005-01-01

    The phase constitution in mixed Gd2O3 and B4C by sintering in graphite tube furnace at the temperature of 100~1489 ℃ in argon atmosphere was studied by means of XRD and TG-DTA. The results show that the impurity C reacts with O in the B4C at the temperature of 367~458 ℃. When the temperature is 800 ℃, Gd2O3 reacts with B4C, and the reaction products include GdB6, GdB4, GdBO3, GdBC and B. GdBC changes into GdB4 at 1200 ℃. When the temperature is 1470 ℃, GdB6 is obtained by the reaction of GdB4 with elemental B. The content of GdB6 is increasing with the prolonging time.

  9. Fabrication and Properties of SiB6-B4C with Phenolic Resin as a Carbon Source

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Si-B-C ceramic composites were synthesized using SiB6, B4C, and phenolic resin as a carbon source by pressureless sintering in an Ar atmosphere. Then, the Si-B-C ceramic composites were fabricated to determine their potential for applications as high hardness and high temperature composites. The X-ray diffraction patterns of sintered bodies of SiB6-B4C with carbonized phenolic resin can be seen that SiB6 and C changed to B4C and SiC. In this study, it is obtained that carbonized phenolic resin is good addition material as a reaction material comparing to carbon powder at 1683 K for 1 h by pressureless sintering in an Ar atmosphere.

  10. [Continuous cell subline A4C2/9K and its application to the african swine fever virus study].

    Science.gov (United States)

    Balysheva, V I; Prudnikova, E Yu; Galnbek, T V; Balyshev, V M

    2015-01-01

    A new continuous cell subline A4C2/9K highly sensitive to the african swine fever virus (ASFV) was prepared. All the tested ASFV strains isolated in the Russian Federation in 2008-2013 proliferated in this cell culture exhibiting hemadsorption and accumulated at a titer of up to 6.5 Ig HAU50/cm3. The cell culture A4C2/9K can be used for ASFV isolation or determination of its infectious activity and serotype identity. The culture versions of the ASFV strain Stavropol 01/08 at passages 24 and 33 in the cell culture A4C2/9K lost their pathogenicity for pigs.

  11. Temperature, gravity, and bolometric correction scales for non-supergiant OB stars

    Science.gov (United States)

    Nieva, M.-F.

    2013-02-01

    Context. Precise and accurate determinations of the atmospheric parameters effective temperature and surface gravity are mandatory to derive reliable chemical abundances in OB stars. Furthermore, fundamental parameters like distances, masses, radii, luminosities can also be derived from the temperature and gravity of the stars. Aims: Atmospheric parameters recently determined at high precision with several independent spectroscopic indicators in non-local thermodynamic equilibrium, with typical uncertainties of ~300 K for temperature and of ~0.05 dex for gravity, are employed to calibrate photometric relationships. This is in order to investigate whether a faster tool to estimate atmospheric parameters can be provided. Methods: Temperatures and gravities of 30 calibrators, i.e. well-studied OB main sequence to giant stars in the solar neighbourhood, are compared to reddening-independent quantities of the Johnson and Strömgren photometric systems, assuming normal reddening. In addition, we examine the spectral and luminosity classification of the star sample and compute bolometric corrections. Results: Calibrations of temperatures and gravities are proposed for various photometric indices and spectral types. Once the luminosity of the stars is well known, effective temperatures can be determined at a precision of ~400 K for luminosity classes III/IV and ~800 K for luminosity class V. Furthermore, surface gravities can reach internal uncertainties as low as ~0.08 dex when using our calibration to the Johnson Q-parameter. Similar precision is achieved for gravities derived from the β-index and the precision is lower for both atmospheric parameters when using the Strömgren indices [c1] and [u - b] . In contrast, external uncertainties are larger for the Johnson than for the Strömgren calibrations. Our uncertainties are smaller than typical differences among other methods in the literature, reaching values up to ± 2000 K for temperature and ± 0.25 dex for gravity

  12. Actions of a proline analogue, L-thiazolidine-4-carboxylic acid (T4C, on Trypanosoma cruzi.

    Directory of Open Access Journals (Sweden)

    Anahí Magdaleno

    Full Text Available It is well established that L-proline has several roles in the biology of trypanosomatids. In Trypanosoma cruzi, the etiological agent of Chagas' disease, this amino acid is involved in energy metabolism, differentiation processes and resistance to osmotic stress. In this study, we analyzed the effects of interfering with L-proline metabolism on the viability and on other aspects of the T. cruzi life cycle using the proline analogue L- thiazolidine-4-carboxylic acid (T4C. The growth of epimastigotes was evaluated using different concentrations of T4C in standard culture conditions and at high temperature or acidic pH. We also evaluated possible interactions of this analogue with stress conditions such as those produced by nutrient starvation and oxidative stress. T4C showed a dose-response effect on epimastigote growth (IC(50 = 0.89+/-0.02 mM at 28 degrees C, and the inhibitory effect of this analogue was synergistic (p<0.05 with temperature (0.54+/-0.01 mM at 37 degrees C. T4C significantly diminished parasite survival (p<0.05 in combination with nutrient starvation and oxidative stress conditions. Pre-incubation of the parasites with L-proline resulted in a protective effect against oxidative stress, but this was not seen in the presence of the drug. Finally, the trypomastigote bursting from infected mammalian cells was evaluated and found to be inhibited by up to 56% when cells were treated with non-toxic concentrations of T4C (between 1 and 10 mM. All these data together suggest that T4C could be an interesting therapeutic drug if combined with others that affect, for example, oxidative stress. The data also support the participation of proline metabolism in the resistance to oxidative stress.

  13. Synthesis of LiFePO{sub 4}/C cathode materials through an ultrasonic-assisted rheological phase method

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Hyun-Ju; Kim, Jeong-Min [Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of); Kim, Woo-Seong [Daejung EM Co., Incheon 429-450 (Korea, Republic of); Koo, Hoe-Jin [Battery R and D Association of Korea, Seoul 137-894 (Korea, Republic of); Bae, Dong-Sik [Changwon National University, Changwon 641-773 (Korea, Republic of); Kim, Hyun-Soo, E-mail: hskim@keri.re.kr [Korea Electrotechnology Research Institute, Changwon 641-120 (Korea, Republic of)

    2011-05-05

    Graphical abstract: Display Omitted Highlights: > LiFePO{sub 4}/C active material was synthesized using an ultrasonic-assisted rheological phase method. > In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO{sub 4} particles for enhanced electrical conductivity. > The synthesized particle had a size range of 100 {approx} 150 nm and a carbon layer of about 8 nm. > The LiFePO{sub 4}/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. - Abstract: LiFePO{sub 4}/C active material was synthesized using an ultrasonic-assisted rheological phase method. In addition, polyvinyl butyral (PVB) was added in various concentrations to provide carbon coating on the surface of the LiFePO{sub 4} particles for enhanced electrical conductivity. The crystal structure, morphology, and carbon coating layer of the synthesized LiFePO{sub 4}/C was analyzed using X-ray diffraction (XRD), scanning electron microscopy (SEM), and transmission electron microscopy (TEM), respectively. The electrochemical performance of LiFePO{sub 4}/C, such as initial capacity, rate capability, cycling performance and EIS, were also evaluated. The synthesized particle had a size range of 100-150 nm and a carbon layer of about 8 nm. The LiFePO{sub 4}/C (5 wt% PVB) delivered an initial discharge capacity of 167.5 mAh/g at a 0.1 C rate. It also showed an excellent capacity retention ratio of 100% after the 50th charging/discharging. EIS results demonstrate that the charge transfer resistance of the sample decreases greatly by coating with 5 wt% PVB.

  14. DUX4c is up-regulated in FSHD. It induces the MYF5 protein and human myoblast proliferation.

    Directory of Open Access Journals (Sweden)

    Eugénie Ansseau

    Full Text Available Facioscapulohumeral muscular dystrophy (FSHD is a dominant disease linked to contractions of the D4Z4 repeat array in 4q35. We have previously identified a double homeobox gene (DUX4 within each D4Z4 unit that encodes a transcription factor expressed in FSHD but not control myoblasts. DUX4 and its target genes contribute to the global dysregulation of gene expression observed in FSHD. We have now characterized the homologous DUX4c gene mapped 42 kb centromeric of the D4Z4 repeat array. It encodes a 47-kDa protein with a double homeodomain identical to DUX4 but divergent in the carboxyl-terminal region. DUX4c was detected in primary myoblast extracts by Western blot with a specific antiserum, and was induced upon differentiation. The protein was increased about 2-fold in FSHD versus control myotubes but reached 2-10-fold induction in FSHD muscle biopsies. We have shown by Western blot and by a DNA-binding assay that DUX4c over-expression induced the MYF5 myogenic regulator and its DNA-binding activity. DUX4c might stabilize the MYF5 protein as we detected their interaction by co-immunoprecipitation. In keeping with the known role of Myf5 in myoblast accumulation during mouse muscle regeneration DUX4c over-expression activated proliferation of human primary myoblasts and inhibited their differentiation. Altogether, these results suggested that DUX4c could be involved in muscle regeneration and that changes in its expression could contribute to the FSHD pathology.

  15. Og4C3 circulating antigen: a marker of infection and adult worm burden in Wuchereria bancrofti filariasis.

    Science.gov (United States)

    Chanteau, S; Moulia-Pelat, J P; Glaziou, P; Nguyen, N L; Luquiaud, P; Plichart, C; Martin, P M; Cartel, J L

    1994-07-01

    Og4C3 circulating filarial antigen was detected in the sera of 94.5% (259/274) of microfilaremic patients, 32% (239/751) of persons with presumption of filariasis, and 23% (11/48) of chronic filariasis patients. The antigen level was correlated with the microfilariae (Mf) density and patient age (P < .01). It remained stable in patients treated with microfilaricidal drugs. Og4C3 antigen, undetectable in Mf culture media, was demonstrated to be a rare somatic Mf antigen. It appears to be an excreted or secreted antigen from adult filaria. It could be used as a marker of infection and an indicator of adult worm burden.

  16. On the possibility of the reaction (CuMoO4 + C, using the apparent activation energy method

    Directory of Open Access Journals (Sweden)

    A. D. Mekhtiev

    2015-07-01

    Full Text Available This article discusses the calculation of the apparent activation energy (CuМоO4 + C on the DTA (Differential Thermal Analysis curve, to study and optimize the time-temperature synthesis mode, in particular, the activation energy. Activation energy allows us to investigate the elementary act of chemical interaction. Thus, we propose to use this method to calculate the interaction of Eact (CuМоO4 + C in the solid phase of hardening occurring during synthesis. These results allow us to trace how much energy is expended to start the reaction.

  17. Synthesis of LiFePO_4/C Composite Cathode Materials Using High Surface Area Carbon as Carbon Sources

    Institute of Scientific and Technical Information of China (English)

    George; Ting-kuo; Fey; Kai-Lun; Chiang

    2007-01-01

    1 Results The pyrolyzed product of peanut shells was utilized as a carbon source to synthesize a LiFePO4/C composite.The advantages of using agricultural wastes such as peanut shells are low costs,easy processing,and environmentally benigness.Peanut shell was first treated with a porogenic agent to produce a precursor with high porosity and surface area (>2 000 m2·g-1).A small amount of precursor was mixed with LiFePO4 fine powders and heated.The optimum calcination process for synthesizing LiFePO4/C co...

  18. Effect of Al4C3 on Microstructure and Properties of AM60A Magnesium Alloy%Al4C3对AM60A镁合金组织和性能的影响

    Institute of Scientific and Technical Information of China (English)

    陈欣; 秦建军; 欧耀辉; 陈阳; 孙伟

    2012-01-01

    The microstructures and properties of AM60A magnesium alloy with different content of ALA were studied using the optical microscope (OM), scanning electron microscope (SEM) and energy-dispersive X-ray spectroscopy (EDS). It was found that the addition of AI4C3 can promote the refinement of AM60A magnesium alloy. A best refining result can be gained when 0.5 wt% ALA was added, and the best mechanical properties and corrosion resistance of the alloy can be reached. Based on the calculation of the planar disregistry between ALA and a-Mg, AI4C3 particles can act as the heterogeneous nucleus of primary ot-Mg phase. But when the addition amount of ALA is over the range of 0.5% to 0.7%, the agglomeration and precipitation of ALA can decrease the grain refinement effect.%采用光学显微镜(OM)、扫描电镜(SEM)及能谱分析(EDS)等测试手段研究了不同含量的Al4C3对AM60A镁合金组织和性能的影响.结果表明,Al4C3的加入可以显著细化AM60A镁合金的晶粒;当其含量为0.5%时,晶粒最为细小,合金的强韧性与耐腐蚀性能得到最大改善.通过能谱分析及面错配度的计算证实:Al4C3可作为初生α-Mg的良好异质核心,但当Al4C3的加入量超过一定范围(大于0.5%~0.7%)时,大量的Al4C3生团聚和沉淀,造成晶粒细化效果下降.

  19. Fatigue performance and fracture mechanism of B4C/6061Al composites%B4C/6061铝基复合材料疲劳性能及断裂机制

    Institute of Scientific and Technical Information of China (English)

    秦艳兵; 王文先; 李宇力; 张鹏; 王保东

    2014-01-01

    基于轻质、高强和耐磨等诸多优势,铝基碳化硼复合材料已成为集结构/功能一体化的新型材料。本文采用粉末冶金及轧制方法,制备出厚度3.5 mm、碳化硼质量分数为33%的B4C/Al复合材料板材,并对其疲劳性能和断裂机制进行分析。在1×107循环次数下,铝基碳化硼复合材料板材的疲劳强度达到110 MPa。采用SEM对疲劳断口进行观察,结果表明B4C/Al复合材料疲劳断口可清楚的看到裂纹的萌生、扩展和失稳断裂的典型特征,但存在多种形式的疲劳启裂源。疲劳裂纹扩展路径取决于裂纹尖端塑性区的半径和B4C颗粒的间距大小,当增强颗粒的间距小于塑性区半径时,裂纹主要沿着颗粒的连接界面或断裂的碳化硼颗粒扩展,当增强颗粒的间距大于塑性区半径时,有利于裂纹尖端钝化,减缓裂纹的扩展和方向改变。%With the advantages of low density, high strength and wear resistance, etc, the aluminum matrix composite reinforced by ceramic particles has became a new material which integrating structure and function. The B4C/Al composite with mass fraction of 33% of boron carbide and the plates of thickness 3.5 mm were manufactured by powder metallurgy and rolling. The fatigue performance and fracture mechanism of B4C/Al composite were studied. Fatigue experiment concludes that the fatigue limit of B4C/Al composite is 110 MPa under 1×107 fatigue cycles. SEM and EDS were used to observe the fatigue fracture and analyze the fracture points. The characteristics of crack initiation, crack propagation, unstability to breakdown were found on the fatigue fracture surface, and different kinds of fatigue source exist in the B4C/Al composite; The fatigue crack extension path of B4C/aluminium composites with a high content of boron carbide depends on the particle interval of B4C and radius of the crack tip plastic zone. When the radius of crack tip is bigger than the

  20. The rotation period distributions of 4--10 Myr T Tauri stars in Orion OB1: New constraints on pre-main-sequence angular momentum evolution

    CERN Document Server

    Karim, Md Tanveer; Briceno, Cesar; Vivas, A Katherina; Raetz, Stefanie; Mateu, Cecilia; Downes, Juan Jose; Calvet, Nuria; Hernandez, Jesus; Neuhauser, Ralph; Mugrauer, Markus; Takahashi, Hidenori; Tachihara, Kengo; Chini, Rolf; Cruz-Dias, Gustavo A; Aarnio, Alicia; James, David J; Hackstein, Moritz

    2016-01-01

    Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (1-3 Myr) T Tauri stars. In contrast, the angular momentum distributions of older T Tauri stars (4-10 Myr) have been less studied, even though they hold key insight to understanding stellar angular momentum evolution at a time when protoplanetary disks have largely dissipated and when models therefore predict changes in the rotational evolution that can in principle be tested. We present a study of photometric variability among 1,974 confirmed T Tauri members of various sub-regions of the Orion OB1 association, and with ages spanning 4-10 Myr, using optical time-series from three different surveys. For 564 of the stars (~32% of the weak-lined T Tauri stars and ~13% of the classical T Tauri stars in our sample) we detect statistically significant periodic variations which we attribute to the stellar rotation periods, making this one of the largest samples of T Tauri star rotation periods yet publis...

  1. The Star-formation History and Accretion-Disk Fraction Among the K-Type Members of the Scorpius-Centaurus OB Association

    CERN Document Server

    Pecaut, Mark J

    2016-01-01

    We present results of a spectroscopic survey for new K- and M-type members of Scorpius-Centaurus (Sco-Cen), the nearest OB Association (~100-200 pc). Using an X-ray, proper motion and color-magnitude selected sample, we obtained spectra for 361 stars, for which we report spectral classifications and Li and Halpha equivalent widths. We identified 156 new members of Sco-Cen, and recovered 51 previously published members. We have combined these with previously known members to form a sample of 493 solar-mass (~0.7-1.3 Msun) members of Sco-Cen. We investigated the star-formation history of this sample, and re-assessed the ages of the massive main-sequence turn-off and the G-type members in all three subgroups. We performed a census for circumstellar disks in our sample using WISE infrared data and find a protoplanetary disk fraction for K-type stars of 4.4$^{+1.6}_{-0.9}$% for Upper Centaurus-Lupus and Lower Centaurus-Crux at ~16 Myr and 9.0$^{+4.0}_{-2.2}$% for Upper Scorpius at ~10 Myr. These data are consisten...

  2. The Rotation Period Distributions of 4-10 Myr T Tauri Stars in Orion OB1: New Constraints on Pre-main-sequence Angular Momentum Evolution

    Science.gov (United States)

    Karim, Md Tanveer; Stassun, Keivan G.; Briceño, César; Vivas, A. Katherina; Raetz, Stefanie; Mateu, Cecilia; José Downes, Juan; Calvet, Nuria; Hernández, Jesús; Neuhäuser, Ralph; Mugrauer, Markus; Takahashi, Hidenori; Tachihara, Kengo; Chini, Rolf; Cruz-Dias, Gustavo A.; Aarnio, Alicia; James, David J.; Hackstein, Moritz

    2016-12-01

    Most existing studies of the angular momentum evolution of young stellar populations have focused on the youngest (≲1-3 Myr) T Tauri stars. In contrast, the angular momentum distributions of older T Tauri stars (˜4-10 Myr) have been less studied, even though they hold key insights to understanding stellar angular momentum evolution at a time when protoplanetary disks have largely dissipated and when models therefore predict changes in the rotational evolution that can in principle be tested. We present a study of photometric variability among 1974 confirmed T Tauri members of various subregions of the Orion OB1 association, and with ages spanning 4-10 Myr, using optical time series from three different surveys. For 564 of the stars (˜32% of the weak-lined T Tauri stars and ˜13% of the classical T Tauri stars in our sample) we detect statistically significant periodic variations, which we attribute to the stellar rotation periods, making this one of the largest samples of T Tauri star rotation periods yet published. We observe a clear change in the overall rotation period distributions over the age range 4-10 Myr, with the progressively older subpopulations exhibiting systematically faster rotation. This result is consistent with angular momentum evolution model predictions of an important qualitative change in the stellar rotation periods starting at ˜5 Myr, an age range for which very few observational constraints were previously available.

  3. ob/ob 与野生型小鼠脂肪组织的磁共振波谱研究%In vivo detection of fat quantitative and qualitative study using 1 H-MRS in ob/ob and WT mice

    Institute of Scientific and Technical Information of China (English)

    彭新桂; 柏盈盈; 居胜红

    2014-01-01

    Objective: To evaluate hydrogen MR spectroscopy ( 1 H-MRS ) in estimating lipid content of whole body and measuring fat content in white and brown adipose tissue ( WAT and BAT ) of obese and normal mice in vivo.Methods:A single pulse 1 H-MRS and a localized proton 1 H-MRS were performed to measure the triglyceride from the whole body and the lipid contents in WAT and BAT of six ob/ob and six wild type(WT) mice using 7T micro-MR scanner . Fractions of unsaturated fatty acids ( FU ) , diunsaturated fatty acids ( FDU ) and polyunsaturation degree ( PUD) in WAT and BAT were calculated by using MRS .Independent-sample t test was performed in comparison .Results:In vivo total body spectroscopy showed the liquid lipid accumulation degree on the whole body in ob/ob mice was significantly higher than that of controls ( P0.05).PUD value and FDU of WAT in ob/ob mice were significantly lower than those of WT mice ( P0.05).Conclusion: 1H-MRS is efficient method in fat quantification at 7.0 T MR.In additions, MRS analyses PUD value and FU of WAT or BAT.They have the potential for further application quantization of lipid composition and lipometabolism in longitudinal studies .%目的:探讨超高场强磁共振氢质子波谱( hydrogen MR spectroscopy ,1 H-MRS)在全面评价ob/ob鼠及野生对照组小鼠白色脂肪组织和棕色脂肪脂质成分中的作用。方法:运用整体和单体素1 H-MRS方法对ob/ob及野生对照鼠进行活体波谱分析,整体1 H-MRS波谱定量全身脂质;单体素波谱计算白色和棕色脂肪的脂质含量,饱和及不饱和脂肪酸、双不饱和脂肪酸的相对含量及多聚不饱和程度。结果:整体1 H-MRS结果显示ob/ob鼠全身脂质含量显著高于野生型对照组,单体素1 H-MRS显示ob/ob鼠棕色脂肪脂质含量显著高于野生对照组,而两组鼠白色脂肪脂质含量的差异无统计学意义,ob/ob鼠白色脂肪的双不饱和脂肪酸及多聚不饱和程度均低

  4. A Correlation Between Circumstellar Disks and Rotation in the Upper Scorpius OB Association

    CERN Document Server

    Dahm, S E; White, R J

    2011-01-01

    We present projected rotational velocities for 20 early-type (B8-A9) and 74 late-type (F2-M8) members of the ~5 Myr old Upper Scorpius OB Association derived from high dispersion optical spectra obtained with the High Resolution Echelle Spectrometer (HIRES) on Keck I and the Magellan Inamori Kyocera Echelle (MIKE) on the Magellan Clay telescope. The spectroscopic sample is composed of stars and brown dwarfs with infrared signatures of circumstellar disks, both primordial and debris, and non-excess sources of comparable spectral type. We merge projected rotational velocities, accretion diagnostics, and Spitzer Space Telescope Infrared Array Camera (IRAC) and Multiband Imaging Photometer for Spitzer (MIPS) 24 micron photometry to examine the relationship between rotation and circumstellar disks. The rotational velocities are strongly correlated with spectral type, a proxy for mass, such that the median vsini for B8-A9 type stars is: 195(+/-)70 km/s, F2-K4: 37.8(+/-)7.4 km/s, K5-K9: 13.8(+21.3/-8.2) km/s, M0-M5:...

  5. The Escape of Ionizing Photons from OB Associations in Disk Galaxies Radiation Transfer Through Superbubbles

    CERN Document Server

    Dove, J B; Ferrara, A; Dove, James B.; Ferrara, Andrea

    1999-01-01

    By solving the time-dependent radiation transfer problem of stellar radiation through evolving superbubbles within a smoothly varying H I distribution, we have estimated the fraction of ionizing photons emitted by OB associations that escapes the H I disk of our Galaxy. We considered a coeval star-formation history and a Gaussian star-formation history with a time spread sigma_t = 2 Myr. We find that the shells of the expanding superbubbles quickly trap or attenuate the ionizing flux, such that most of the escaping radiation escapes shortly after the formation of the superbubble. Superbubbles of large associations can blowout of the H I disk and form dynamic chimneys, which allow the ionizing radiation directly to escape the H I disk. However, blowout occurs when the ionizing photon luminosity has dropped well below the association's maximum luminosity. For the coeval star-formation history, the fraction of photons that escape each side of the disk in the solar vicinity is f_esc approx 6% (the total fraction ...

  6. New Version of SeismicHandler (SHX) based on ObsPy

    Science.gov (United States)

    Stammler, Klaus; Walther, Marcus

    2016-04-01

    The command line version of SeismicHandler (SH), a scientific analysis tool for seismic waveform data developed around 1990, has been redesigned in the recent years, based on a project funded by the Deutsche Forschungsgemeinschaft (DFG). The aim was to address new data access techniques, simplified metadata handling and a modularized software design. As a result the program was rewritten in Python in its main parts, taking advantage of simplicity of this script language and its variety of well developed software libraries, including ObsPy. SHX provides an easy access to waveforms and metadata via arclink and FDSN webservice protocols, also access to event catalogs is implemented. With single commands whole networks or stations within a certain area may be read in, the metadata are retrieved from the servers and stored in a local database. For data processing the large set of SH commands is available, as well as the SH scripting language. Via this SH language scripts or additional Python modules the command set of SHX is easily extendable. The program is open source, tested on Linux operating systems, documentation and download is found at URL "https://www.seismic-handler.org/".

  7. An Updated Look at Binary Characteristics of Massive Stars in the Cygnus OB2 Association

    CERN Document Server

    Kiminki, Daniel C

    2012-01-01

    This work provides a statistical analysis of the massive star binary characteristics in the Cygnus OB2 Association using radial velocity information of 114 B3-O3 primary stars and orbital properties for the 24 known binaries. We compare these data to a series of Monte Carlo simulations to infer the intrinsic binary fraction and distributions of mass ratios, periods, and eccentricities. We model the distribution of mass ratio, log-period, and eccentricity as power-laws and find best fitting indices of alpha=0.1+/-0.5, beta=0.2+/-0.4, and gamma=-0.6+/-0.3 respectively. These distributions indicate a preference for massive companions, short periods, and low eccentricities. Our analysis indicates that the binary fraction of the cluster is 44+/-8% if all binary systems are (artificially) assumed to have P<1000 days; if the power-law period distribution is extrapolated to 10^4 years, a plausible upper limit for bound systems, the binary fraction is ~90+/-10%. Of these binary (or higher order) systems, ~45% will ...

  8. DIRECT IMAGING AND SPECTROSCOPY OF A YOUNG EXTRASOLAR KUIPER BELT IN THE NEAREST OB ASSOCIATION

    Energy Technology Data Exchange (ETDEWEB)

    Currie, Thayne [National Astronomical Observatory of Japan, Subaru Telescope, Hilo, HI (United States); Lisse, Carey M. [Applied Physics Laboratory, The Johns Hopkins University, Laurel, MD (United States); Kuchner, Marc [NASA Goddard Space Flight Center, Greenbelt, MD (United States); Madhusudhan, Nikku [Institute for Astronomy, University of Cambridge, Cambridge (United Kingdom); Kenyon, Scott J. [Harvard-Smithsonian Center for Astrophysics, Cambridge, MA (United States); Thalmann, Christian [ETH-Zurich, Zurich (Switzerland); Carson, Joseph [Department of Physics and Astronomy, The College of Charleston, Charleston, SC (United States); Debes, John [Space Telescope Science Institute, Baltimore, MD (United States)

    2015-07-01

    We describe the discovery of a bright, young Kuiper belt–like debris disk around HD 115600, a ∼1.4–1.5 M{sub ⊙}, ∼15 Myr old member of the Sco–Cen OB Association. Our H-band coronagraphy/integral field spectroscopy from the Gemini Planet Imager shows the ring has a (luminosity-scaled) semimajor axis of (∼22 AU) ∼ 48 AU, similar to the current Kuiper belt. The disk appears to have neutral-scattering dust, is eccentric (e ∼ 0.1–0.2), and could be sculpted by analogs to the outer solar system planets. Spectroscopy of the disk ansae reveal a slightly blue to gray disk color, consistent with major Kuiper belt chemical constituents, where water ice is a very plausible dominant constituent. Besides being the first object discovered with the next generation of extreme adaptive optics systems (i.e., SCExAO, GPI, SPHERE), HD 115600's debris ring and planetary system provide a key reference point for the early evolution of the solar system, the structure, and composition of the Kuiper belt and the interaction between debris disks and planets.

  9. Direct Imaging and Spectroscopy of a Young Extrasolar Kuiper Belt in the Nearest OB Association

    CERN Document Server

    Currie, Thayne; Kuchner, Marc J; Madhusudhan, Nikku; Kenyon, Scott J; Thalmann, Christian; Carson, Joseph; Debes, John H

    2015-01-01

    We describe the discovery of a bright, young Kuiper belt-like debris disk around HD 115600, a $\\sim$ 1.4--1.5 M$_\\mathrm{\\odot}$, $\\sim$ 15 Myr old member of the Sco-Cen OB Association. Our H-band coronagraphy/integral field spectroscopy from the \\textit{Gemini Planet Imager} shows the ring has a (luminosity scaled) semi major axis of ($\\sim$ 22 AU) $\\sim$ 48 AU, similar to the current Kuiper belt. The disk appears to have neutral scattering dust, is eccentric (e $\\sim$ 0.1--0.2), and could be sculpted by analogues to the outer solar system planets. Spectroscopy of the disk ansae reveal a slightly blue to gray disk color, consistent with major Kuiper belt chemical constituents, where water-ice is a very plausible dominant constituent. Besides being the first object discovered with the next generation of extreme adaptive optics systems (i.e. SCExAO, GPI, SPHERE), HD 115600's debris ring and planetary system provides a key reference point for the early evolution of the solar system, the structure and compositio...

  10. Targeting the OB-Folds of Replication Protein A with Small Molecules

    Directory of Open Access Journals (Sweden)

    Victor J. Anciano Granadillo

    2010-01-01

    Full Text Available Replication protein A (RPA is the main eukaryotic single-strand (ss DNA-binding protein involved in DNA replication and repair. We have identified and developed two classes of small molecule inhibitors (SMIs that show in vitro inhibition of the RPA-DNA interaction. We present further characterization of these SMIs with respect to their target binding, mechanism of action, and specificity. Both reversible and irreversible modes of inhibition are observed for the different classes of SMIs with one class found to specifically interact with DNA-binding domains A and B (DBD-A/B of RPA. In comparison with other oligonucleotide/oligosaccharide binding-fold (OB-fold containing ssDNA-binding proteins, one class of SMIs displayed specificity for the RPA protein. Together these data demonstrate that the specific targeting of a protein-DNA interaction can be exploited towards interrogating the cellular activity of RPA as well as increasing the efficacy of DNA-damaging chemotherapeutics used in cancer treatment.

  11. ALMA Observations of Circumstellar Disks in the Upper Scorpius OB Association

    CERN Document Server

    Barenfeld, Scott A; Ricci, Luca; Isella, Andrea

    2016-01-01

    We present ALMA observations of 106 G-, K-, and M-type stars in the Upper Scorpius OB Association hosting circumstellar disks. With these data, we measure the 0.88 mm continuum and $^{12}$CO $J = 3-2$ line fluxes of disks around low mass ($0.14-1.66$ $M_{\\odot}$) stars at an age of 5-11 Myr. Of the 75 primordial disks in the sample, 53 are detected in the dust continuum and 26 in CO. Of the 31 disks classified as debris/evolved transitional disks, 5 are detected in the continuum and none in CO. The lack of CO emission in approximately half of the disks with detected continuum emission can be explained if CO is optically thick but has a compact emitting area ($\\lesssim 40$ AU), or if the CO is heavily depleted by a factor of at least $\\sim1000$ relative to interstellar medium abundances and is optically thin. The continuum measurements are used to estimate the dust mass of the disks. We find a correlation between disk dust mass and stellar host mass consistent with a power-law relation of $M_{dust}\\propto M_*^...

  12. The eclipsing, double-lined, Of supergiant binary Cygnus OB2-B17

    Science.gov (United States)

    Stroud, V. E.; Clark, J. S.; Negueruela, I.; Roche, P.; Norton, A. J.; Vilardell, F.

    2010-02-01

    Context. Massive, eclipsing, double-lined, spectroscopic binaries are not common but are necessary to understand the evolution of massive stars as they are the only direct way to determine stellar masses. They are also the progenitors of energetic phenomena such as X-ray binaries and γ-ray bursts. Aims: We present a photometric and spectroscopic analysis of the candidate binary system Cyg OB2-B17 to show that it is indeed a massive evolved binary. Methods: We utilise V band and white-light photometry to obtain a light curve and period of the system, and spectra at different resolutions to calculate preliminary orbital parameters and spectral classes for the components. Results: Our results suggest that B17 is an eclipsing, double-lined, spectroscopic binary with a period of 4.0217±0.0004 days, with two massive evolved components with preliminary classifications of O7 and O9 supergiants. The radial velocity and light curves are consistent with a massive binary containing components with similar luminosities, and in turn with the preliminary spectral types and age of the association.

  13. The eclipsing, double-lined, Of supergiant binary Cyg OB2-B17

    CERN Document Server

    Stroud, V E; Negueruela, I; Roche, P; Norton, A J; Vilardell, F

    2010-01-01

    Massive, eclipsing, double-lined, spectroscopic binaries are not common but are necessary to understand the evolution of massive stars as they are the only direct way to determine stellar masses. They are also the progenitors of energetic phenomena such as X-ray binaries and gamma-ray bursts. We present a photometric and spectroscopic analysis of the candidate binary system Cyg OB2-B17 to show that it is indeed a massive evolved binary. We utilise V band and white-light photometry to obtain a light curve and period of the system, and spectra at different resolutions to calculate preliminary orbital parameters and spectral classes for the components. Our results suggest that B17 is an eclipsing, double-lined, spectroscopic binary with a period of 4.0217+/-0.0004 days, with two massive evolved components with preliminary classifications of O7 and O9 supergiants. The radial velocity and light curves are consistent with a massive binary containing components with similar luminosities, and in turn with the prelimi...

  14. Isolation and Purification of Cu-free Methanobactin from Methylosinus trichosporium OB3b

    Energy Technology Data Exchange (ETDEWEB)

    M Pesch; I Christl; K Barmettler; S Kraemer; R Kretzschmar

    2011-12-31

    The isolation of highly pure copper-free methanobactin is a prerequisite for the investigation of the biogeochemical functions of this chalkophore molecule produced by methane oxidizing bacteria. Here, we report a purification method for methanobactin from Methylosinus trichosporium OB3b cultures based on reversed-phase HPLC fractionation used in combination with a previously reported resin extraction. HPLC eluent fractions of the resin extracted product were collected and characterized with UV-vis, FT-IR, and C-1s NEXAFS spectroscopy, as well as with elemental analysis and ESI-MS. The results showed that numerous compounds other than methanobactin were present in the isolate obtained with resin extraction. Molar C/N ratios, mass spectrometry measurements, and UV-vis spectra indicated that methanobactin was only present in one of the HPLC fractions. On a mass basis, methanobactin carbon contributed only 32% to the total organic carbon isolated with resin extraction. Our spectroscopic results implied that besides methanobactin, the organic compounds in the resin extract comprised breakdown products of methanobactin as well as polysaccharide-like substances. Our results demonstrate that a purification step is indispensable in addition to resin extraction in order to obtain pure methanobactin. The proposed HPLC purification procedure is suitable for semi-preparative work and provides copper-free methanobactin.

  15. Isolation and purification of Cu-free methanobactin from Methylosinus trichosporium OB3b

    Directory of Open Access Journals (Sweden)

    Kraemer Stephan M

    2011-02-01

    Full Text Available Abstract Background The isolation of highly pure copper-free methanobactin is a prerequisite for the investigation of the biogeochemical functions of this chalkophore molecule produced by methane oxidizing bacteria. Here, we report a purification method for methanobactin from Methylosinus trichosporium OB3b cultures based on reversed-phase HPLC fractionation used in combination with a previously reported resin extraction. HPLC eluent fractions of the resin extracted product were collected and characterized with UV-vis, FT-IR, and C-1s NEXAFS spectroscopy, as well as with elemental analysis and ESI-MS. Results The results showed that numerous compounds other than methanobactin were present in the isolate obtained with resin extraction. Molar C/N ratios, mass spectrometry measurements, and UV-vis spectra indicated that methanobactin was only present in one of the HPLC fractions. On a mass basis, methanobactin carbon contributed only 32% to the total organic carbon isolated with resin extraction. Our spectroscopic results implied that besides methanobactin, the organic compounds in the resin extract comprised breakdown products of methanobactin as well as polysaccharide-like substances. Conclusion Our results demonstrate that a purification step is indispensable in addition to resin extraction in order to obtain pure methanobactin. The proposed HPLC purification procedure is suitable for semi-preparative work and provides copper-free methanobactin.

  16. Inversion of ocean-bottom seismometer (OBS) waveforms for oceanic crust structure: a synthetic study

    Science.gov (United States)

    Li, Xueyan; Wang, Yanbin; Chen, Yongshun John

    2016-08-01

    The waveform inversion method is applied—using synthetic ocean-bottom seismometer (OBS) data—to study oceanic crust structure. A niching genetic algorithm (NGA) is used to implement the inversion for the thickness and P-wave velocity of each layer, and to update the model by minimizing the objective function, which consists of the misfit and cross-correlation of observed and synthetic waveforms. The influence of specific NGA method parameters is discussed, and suitable values are presented. The NGA method works well for various observation systems, such as those with irregular and sparse distribution of receivers as well as single receiver systems. A strategy is proposed to accelerate the convergence rate by a factor of five with no increase in computational complexity; this is achieved using a first inversion with several generations to impose a restriction on the preset range of each parameter and then conducting a second inversion with the new range. Despite the successes of this method, its usage is limited. A shallow water layer is not favored because the direct wave in water will suppress the useful reflection signals from the crust. A more precise calculation of the air-gun source signal should be considered in order to better simulate waveforms generated in realistic situations; further studies are required to investigate this issue.

  17. Targeting the OB-Folds of Replication Protein A with Small Molecules

    Science.gov (United States)

    Anciano Granadillo, Victor J.; Earley, Jennifer N.; Shuck, Sarah C.; Georgiadis, Millie M.; Fitch, Richard W.; Turchi, John J.

    2010-01-01

    Replication protein A (RPA) is the main eukaryotic single-strand (ss) DNA-binding protein involved in DNA replication and repair. We have identified and developed two classes of small molecule inhibitors (SMIs) that show in vitro inhibition of the RPA-DNA interaction. We present further characterization of these SMIs with respect to their target binding, mechanism of action, and specificity. Both reversible and irreversible modes of inhibition are observed for the different classes of SMIs with one class found to specifically interact with DNA-binding domains A and B (DBD-A/B) of RPA. In comparison with other oligonucleotide/oligosaccharide binding-fold (OB-fold) containing ssDNA-binding proteins, one class of SMIs displayed specificity for the RPA protein. Together these data demonstrate that the specific targeting of a protein-DNA interaction can be exploited towards interrogating the cellular activity of RPA as well as increasing the efficacy of DNA-damaging chemotherapeutics used in cancer treatment. PMID:21188165

  18. Extended Non-Thermal Emission Possibly Associated with Cyg OB2 #5

    CERN Document Server

    Ortiz-Leon, G N; Tapia, M

    2011-01-01

    Cyg OB2 #5 is a contact binary system (O6.5-7+O5.5-6) with associated radio continuum emission. Two compact ($\\leq 0\\rlap.{"}3$) radio continuum components have been reported previously: the primary one is associated with the contact binary and the secondary one is an arc-like source $\\sim 0\\rlap.{"}8$ to the NE of the primary. This arc-like source results from the interaction of the winds of the contact binary and a B-type star in the region. In this paper we report the detection of an extended ($\\sim 30"$), non-thermal component to the NE of the compact components. We propose that this extended emission could be an unresolved background source (i. e. a radio galaxy), extended galactic emission, or non-thermal emission related with relativistic electrons that are produced in the shock between the contact binary and the B-type star and that are carried away to large distances by the wind from the contact binary.

  19. Escape fraction of ionizing photons during reionization: effects due to supernova feedback and runaway OB stars

    CERN Document Server

    Kimm, Taysun

    2014-01-01

    The fraction of hydrogen ionizing photons escaping from galaxies into the intergalactic medium is a critical ingredient in the theory of reionization. We use two zoomed-in, high-resolution (4 pc), cosmological radiation hydrodynamic simulations with adaptive mesh refinement to investigate the impact of two physical mechanisms (supernova feedback and runaway OB stars) on the escape fraction (f_esc) at the epoch of reionization (z>7). We implement a new, physically motivated supernova feedback model that can approximate the Sedov solutions at all (from the free expansion to snowplow) stages. We find that there is a significant time delay of about ten million years between the peak of star formation and that of escape fraction, due to the time required for the build-up and subsequent destruction of the star-forming cloud by supernova feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 10^8-10^10.5 Msun is found to be ~11%, although instantaneous values of f...

  20. Occupational exposure to Am-Be neutron calibration source mounted in OB26 shielding container

    Directory of Open Access Journals (Sweden)

    Szewczak Kamil

    2014-08-01

    Full Text Available Laboratory for Dosimetric and Radon Instruments Calibration which is a part of Central Laboratory for Radiological Protection (CLRP in Warsaw is equipped with 241Am-Be neutron calibration source with activity of 185 GBq since 1999. The capsule was mounted in the OB26 type shielding container. The control room is separated from the above source by a concrete wall of 0.5 m in thickness. The calibration hall is adjacent to one side of the offi ce room. To comply with the requirements of the radiological protection system, the occupational exposure of persons that are working both in the offi ce and control room needs to be assessed. Two methods were involved for ambient dose equivalent rate determination. The active instrument measurements (AIMs performed with the Berthold LB6411 neutron probe and the Monte Carlo simulation method (MCS based on MCNP5 code. These estimations were completed for fi ve reference points. Additionally the γ radiation component was measured by RSS131 ionisation chamber. An increased value of the ambient dose equivalent rate from neutrons was observed in two reference positions. The fi rst observation was done in the control room while the second one in the offi ce room. Expected individual dose equivalents were evaluated based on the results of the AIM and on the expected working time in particular reference points. The annual individual dose equivalent associated with calibration activities using mentioned neutron source was estimated at maximum 0.8 mSv.

  1. Modeling the early evolution of massive OB stars with an experimental wind routine

    CERN Document Server

    Keszthelyi, Zsolt; Wade, Gregg

    2016-01-01

    Stellar evolution models of massive stars are very sensitive to the adopted mass-loss scheme. The magnitude and evolution of mass-loss rates significantly affect the main sequence evolution, and the properties of post-main sequence objects, including their rotational velocities. Driven by potential discrepancies between theoretically predicted and observationally derived mass-loss rates in the OB star range, we particularly aim to investigate the response to mass-loss rates that are lower than currently adopted, in parallel with the mass-loss behavior at the "first" bi-stability jump. We perform 1D hydrodynamical model calculations of single $20 - 60 \\, M_{\\odot}$ Galactic ($Z = 0.014$) stars where the effects of stellar winds are already significant during the main sequence phase. We develop an experimental wind routine to examine the behavior and response of the models under the influence of different mass-loss rates. This observationally guided, simple and flexible wind routine is not a new mass-loss descr...

  2. BOREAS TE-1 CO2 and CH4 Flux Data Over the SSA-OBS Site

    Science.gov (United States)

    Anderson, Darwin; Papagno, Andrea; Hall, Forrest G. (Editor); Newcomer, Jeffrey A. (Editor)

    2000-01-01

    The BOREAS TE-1 team collected various data to characterize the soil-plant systems in the BOREAS SSA. Particular emphasis was placed on nutrient biochemistry, the stores and transfers of organic carbon, and how the characteristics were related to measured methane fluxes. The overall transect in the Prince Albert National Park (Saskatchewan, Canada) included the major plant communities and related soils that occurred in that section of the boreal forest. Soil physical, chemical, and biological measurements along the transect were used to characterize the static environment, which allowed them to be related to methane fluxes. Chamber techniques were used to provide a measure of methane production/uptake. Chamber measurements coupled with flask sampling were used to determine the seasonality of methane fluxes. This particular data set contains carbon dioxide and methane flux values from the SSA-OBS site. The data were collected from 09-Jun to 04-Sep-1994. The data are stored in tabular ASCII files. The data files are available on a CD-ROM (see document number 20010000884), or from the Oak Ridge National Laboratory (ORNL) Distributed Active Archive Center (DAAC).

  3. IRS Spectra of Debris Disks in the Scorpius-Centaurus OB Association

    CERN Document Server

    Jang-Condell, Hannah; Manoj, P; Watson, Dan; Lisse, Carey M; Nesvold, Erika; Kuchner, Marc

    2015-01-01

    We analyze Spitzer/IRS spectra of 110 B-, A-, F-, and G-type stars with optically thin infrared excess in the Scorpius-Centaurus (ScoCen) OB association. The age of these stars ranges from 11-17 Myr. We fit the infrared excesses observed in these sources by Spitzer/IRS and Spitzer/MIPS to simple dust models according to Mie theory. We find that nearly all the objects in our study can be fit by one or two belts of dust. Dust around lower mass stars appears to be closer in than around higher mass stars, particularly for the warm dust component in the two-belt systems, suggesting mass-dependent evolution of debris disks around young stars. For those objects with stellar companions, all dust distances are consistent with trunction of the debris disk by the binary companion. The gaps between several of the two-belt systems can place limits on the planets that might lie between the belts, potentially constraining the mass and locations of planets that may be forming around these stars.

  4. Ethanol production from D-lactic acid by lactic acid-assimilating Saccharomyces cerevisiae NAM34-4C.

    Science.gov (United States)

    Wakamatsu, Makoto; Tani, Tatsunori; Taguchi, Hisataka; Matsuoka, Masayoshi; Kida, Kenji; Akamatsu, Takashi

    2013-07-01

    The lactic acid-assimilating yeast Saccharomyces cerevisiae NAM34-4C grew rapidly in minimal D-lactate medium (pH 3.5) at 35°C, compared with minimal L-lactate medium. A laboratory strain, S. cerevisiae S288C, did not grow in either medium at pH 3.5. Strain NAM34-4C produced remarkably high levels of ethanol in YPDL medium at pH 3.5, but not at pH 5.5, when D-lactate was provided as the carbon source. Optimal cultivation conditions for ethanol production from D-lactate by strain NAM34-4C were as follows: shaking speed, 60 rpm; initial pH, 3.0; cultivation temperature, 35°C; yeast extract, 5 g/L; peptone, 10 g/L; and D-lactate, 30 g/L. Under these conditions, strain NAM34-4C produced 2.7 g/L ethanol, which is 18% of the theoretical maximal yield (0.51 3 initial D-lactate concentration).

  5. The Use of Spray-Dried Mn3O4/C Composites as Electrocatalysts for Li–O2 Batteries

    Directory of Open Access Journals (Sweden)

    Hong-Kai Yang

    2016-11-01

    Full Text Available The electrocatalytic activities of Mn3O4/C composites are studied in lithium–oxygen (Li–O2 batteries as cathode catalysts. The Mn3O4/C composites are fabricated using ultrasonic spray pyrolysis (USP with organic surfactants as the carbon sources. The physical and electrochemical performance of the composites is characterized by X-ray diffraction, scanning electron microscopy, particle size analysis, Brunauer–Emmett–Teller (BET measurements, elemental analysis, galvanostatic charge–discharge methods and rotating ring-disk electrode (RRDE measurements. The electrochemical tests demonstrate that the Mn3O4/C composite that is prepared using Trition X-114 (TX114 surfactant has higher activity as a bi-functional catalyst and delivers better oxygen reduction reaction (ORR and oxygen evolution reaction (OER catalytic performance in Li–O2 batteries because there is a larger surface area and particles are homogeneous with a meso/macro porous structure. The rate constant (kf for the production of superoxide radical (O2•− and the propylene carbonate (PC-electrolyte decomposition rate constant (k for M3O4/C and Super P electrodes are measured using RRDE experiments and analysis in the 0.1 M tetrabutylammonium hexafluorophosphate (TBAPF6/PC electrolyte. The results show that TX114 has higher electrocatalytic activity for the first step of ORR to generate O2•− and produces a faster PC-electrolyte decomposition rate.

  6. Resonant soft x-ray reflectivity of Me/B(4)C multilayers near the boron K edge.

    Science.gov (United States)

    Ksenzov, Dmitriy; Schlemper, Christoph; Pietsch, Ullrich

    2010-09-01

    Energy dependence of the optical constants of boron carbide in the short period Ru/B(4)C and Mo/B(4)C multilayers (MLs) are evaluated from complete reflectivity scans across the boron K edge using the energy-resolved photon-in-photon-out method. Differences between the refractive indices of the B(4)Cmaterial inside and close to the surface are obtained from the peak profile of the first order ML Bragg peak and the reflection profile near the critical angle of total external reflection close to the surface. Where a Mo/B(4)C ML with narrow barrier layers appears as a homogeneous ML at all energies, a Ru/B(4)C ML exhibits another chemical nature of boron at the surface compared to the bulk. From evaluation of the critical angle of total external reflection in the energy range between 184 and 186eV, we found an enriched concentration of metallic boron inside the Ru-rich layer at the surface, which is not visible in other energy ranges.

  7. Effects of different iron sources on the performance of LiFePO4/C composite cathode materials

    Institute of Scientific and Technical Information of China (English)

    2008-01-01

    Olivine LiFePO4/C composite cathode materials were synthesized by a solid state method in N2 + 5vo1% H2 atmosphere.The effects of different iron sources,including Fe(OH)3 and FeC2O4·2H2O,on the performance of as-synthesized cathode materials were investigated and the causes were also analyzed.The crystal structure,the morphology,and the electrochemical performance of the prepared samples were characterized by X-ray diffractometry (XRD),scanning electron microscopy (SEM),laser particle-size distribution measurement,and other electrochemical techniques.The results demonstrate that the LiFePO4/C materials obtained from Fe(OH)3 at 800℃ and FeCeO4·2H2O at 700℃ have the similar electrochemical performances.The initial discharge capacities of LiFePO4/C synthesized from Fe(OH)3 and FeC2O4·2H2O are 134.5 mAh·g-1 and 137.4 mAh.g-1 at the C/5 rate,respectively.However,the tap density of the LiFePO4/C materials obtained from Fe(OH)3 are higher,which is significant for the improvement of the capacity of the battery.

  8. Rapid Polyol-Assisted Microwave Synthesis of Nanocrystalline LiFePO4/C Cathode for Lithium-Ion Batteries.

    Science.gov (United States)

    Paul, Baboo Joseph; Gim, Jihyeon; Baek, Sora; Kang, Jungwon; Song, Jinju; Kim, Sungjin; Kim, Jaekook

    2015-08-01

    Nanocrystalline LiFePO4/C has been synthesized under a very short period of time (90 sec) using a polyol-assisted microwave heating synthesis technique. The X-ray diffraction (XRD) data indicates that the rapidly synthesized materials correspond to phase pure olivine. Post-annealing of the as-prepared sample at 600 °C in argon atmosphere yields highly crystalline LiFePO4/C. The morphology of the samples studied using scanning electron microscopy (SEM) reveals the presence of secondary particles formed from aggregation of primary particles in the range of 30-50 nm. Transmission electron microscopy (TEM) images reveal a thin carbon layer coating on the surface of the primary particle. The charge/discharge studies indicate that the as-prepared and annealed LiFePO4/C samples delivered initial discharge capacities of 126 and 160 mA h g-1, respectively, with good capacity retentions at 0.05 mA cm-2 current densities. The post-annealing process indeed improves the crystallinity of the LiFePO4 nanocrystals, which enhances the electrode performance of LiFePO4/C.

  9. Preparation of V-Doped LiFePO4/C as the Optimized Cathode Material for Lithium Ion Batteries.

    Science.gov (United States)

    Sun, Pingping; Zhang, Haiyang; Shen, Kai; Fan, Qi; Xu, Qingyu

    2015-04-01

    LiFe1-x,Vx,PO4/C composites were synthesized by solid state reaction. The effect of carbon coating and V doping on the performance of LiFePO4 has been systematically investigated by X-ray diffraction (XRD), Raman spectroscopy, X-ray photoelectron spectroscopy (XPS), transmission electron microscope (TEM), charge/discharge and cyclic voltammetry (CV) measurement. The results show that carbon coating and proper amount of V incorporation do not significantly change the host crystal structure of LiFePO4, while the electrochemical performance of LiFePO4 can be significantly improved. Particularly, the LiFe0.96V0.04PO4/C exhibits the best performance with a specific discharge capacity of 105.5 mA h/g at 5.0 C, 90.3 mA h/g at 10 C and 66.7 mA h/g at 30 C with stable cycle performance, which is significantly improved compared with the pure LiFePO4/C. The cyclic voltammograms result reveals that V doping could decrease the resistance of LiFePO4/C composite electrode drastically and improve its reversibility.

  10. Investigation on the Self-discharge of the LiFePO4/C nanophosphate battery chemistry at different conditions

    DEFF Research Database (Denmark)

    Swierczynski, Maciej Jozef; Stroe, Daniel Ioan; Stan, Ana-Irina

    2014-01-01

    it allows also for more precise determination of the actual battery SOC after prolonged storage. In this paper the self-discharge of the nanophosphate LiFePO4/C is studied at different temperature, SOC conditions and at different SOH levels of the battery. Moreover, cell to cell differences in self...

  11. Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating

    Directory of Open Access Journals (Sweden)

    Jianjun Song

    2013-01-01

    Full Text Available Supervalent cation doping and metal oxide coating are the most efficacious and popular methods to optimize the property of LiFePO4 lithium battery material. Mg-doped and MgO-coated LiFePO4/C were synthesized to analyze their individual influence on the electrochemical performance of active material. The specific capacity and rate capability of LiFePO4/C are improved by both MgO coating and Mg doping, especially the Mg-doped sample—Li0.985Mg0.015FePO4/C, whose discharge capacity is up to 163 mAh g−1, 145.5 mAh g−1, 128.3 mAh g−1, and 103.7 mAh g−1 at 1 C, 2 C, 5 C, and 10 C, respectively. The cyclic life of electrode is obviously increased by MgO surface modification, and the discharge capacity retention rate of sample LiFePO4/C-MgO2.5 is up to 104.2% after 100 cycles. Comparing samples modified by these two methods, Mg doping is more prominent on prompting the capacity and rate capability of LiFePO4, while MgO coating is superior in terms of improving cyclic performance.

  12. Low band gap and ionic bonding with charge transfer, threshold in the polymeric lithium fulleride Li(4)C(60)

    NARCIS (Netherlands)

    Macovez, Roberto; Savage, Rebecca; Schiessling, Joachim; Kamaras, Katalin; Rudolf, Petra; Venema, L.C.

    2008-01-01

    We demonstrate the growth of crystalline Li(4)C(60) films. The low-energy electron diffraction pattern of the films indicates the formation of polymer chains in the plane of the surface, consistent with the reported crystal structure. Electron energy loss and photoemission spectra identify the Li(4)

  13. Thermodynamic and kinetic characterization of duplex formation between 2'-O, 4'-C-methylene-modified oligoribonucleotides, DNA and RNA

    DEFF Research Database (Denmark)

    Christensen, Ulla

    2007-01-01

    2'-O,4'-C-methylene-linked ribonucleotide derivatives, named LNA (locked nucleic acid) and BNA (bridged nucleic acid) are nucleic acid analogoues that have shown high-affinity recognition of DNA and RNA, and the employment of LNA oligomers for antisense activity, gene regulation and nucleic acid...... the strength of duplexes formed with the complementary DNA and RNA....

  14. Neutron irradiation tests on B4C/epoxy composite for neutron shielding application and the parameters assay

    Science.gov (United States)

    Adeli, Ruhollah; Shirmardi, Seyed Pezhman; Ahmadi, Seyed Javad

    2016-10-01

    In this investigation, epoxy resin with a low viscosity amine-based curing agent was chosen as matrix and additives were added to epoxy resin using low speed stirring with ultrasonic waves approach. The chemical stability of resin during fabrication of composites was studied with Fourier transform infrared spectroscopy (FTIR). The effect of B4C particle size (20 and 150 μm) on neutron shielding was investigated. Besides, in order to develop the high performance composites, the effect of ATH (flame retardant) and WO3 powders (for shielding from against gamma rays) on neutron shielding property is considered. The neutron experiments were based on foil activation analysis in thermal column of Tehran Research Reactor (TRR). According to experimental data, required shield thickness (B4C, 150 μm, 3 wt%) for 80% absorption of neutron fluence was calculated about 9.8 mm. Consequently, data show thermal neutron absorption is dependent also on the size of the boron compound filler and show a significant enhancement in shielding performance when using smaller particle size of B4C filler. Furthermore, data obviously show that the neutron attenuation coefficient of reinforced composites increases to 0.345 cm-1 for B4C (20 μm, 5 wt%)/ Epoxy composite shield. As clearly data indicate, adding WO3 and ATH additive had a significant influence on the thermal neutron attenuation property and hybrid shield shows an enhancement of more than 60% in shielding performance.

  15. Learning Electrical Circuits: The Effects of the 4C-ID Instructional Approach in the Acquisition and Transfer of Knowledge

    Science.gov (United States)

    Melo, Mário; Miranda, Guilhermina Lobato

    2015-01-01

    This study was designed to investigate the effects of two instructional approaches (4C-ID versus conventional) on learners' knowledge-acquisition and learning transfer of the electrical circuits content in Physics. Participants were 129 9th graders from a secondary school in Lisbon, M = 14.3 years, SD = 0.54. The participants were divided in two…

  16. Preparation and electrochemical characterization of PPy-LiFePO{sub 4}/C composites via vapor-phase polymerization

    Energy Technology Data Exchange (ETDEWEB)

    Gong, Q.; Liao, X.Z.; He, Y.; Yang, Y.; Ma, Z.F. [Shanghai Jiao Tong Univ. (China). Dept. of Chemical Engineering

    2010-07-01

    Polypyrrole (PPy) is now being used as a means of improving the electrochemical performance of lithium-iron (LiFePO{sub 4}/C) composite electrode materials for Li-ion batteries. In this study, core-shell LiFePO{sub 4}/C-PPy composites were prepared using a chemical vapor-phase polymerization technique. Transmission electron microscopy (TEM) analyses demonstrated that the LiFePO{sub 4}/C particles were encapsulated with 7.5-nm thick PPy shells. Electrochemical analyses indicated that the high rate capacities and cycle stability of the composite materials was improved when compared with the performance of LiFePO{sub 4}/C composites. Tests on an MCMB/LiFePO{sub 4}-PPy fuel cell showed that the PPy coating reduced Fe dissolution from the LiFePO{sub 4} cathode, and alleviated subsequent Fe deposition on the MCMB anode, thereby enhancing the cell's life cycle. 7 refs., 2 figs.

  17. Lentivirus-mediated RNA interference targeting the ObR gene in human breast cancer MCF-7 cells in a nude mouse xenograft model

    Institute of Scientific and Technical Information of China (English)

    XUE Rong-quan; GU Jun-chao; DU Song-tao; YU Wei; WANG Yu; ZHANG Zhong-tao; BAI Zhi-gang; MA Xue-mei

    2012-01-01

    Background There is a significant association between obesity and breast cancer,which is possibly due to the expression of leptin.Therefore,it is important to clarify the role of leptin/ObR (leptin receptor) signaling during the progression of human breast cancer.Methods Nude mice with xenografts of MCF-7 human breast cancer cells were administered recombinant human leptin subcutaneous via injection around the tumor site.Mice in the experimental group were intratumorally injected with ObR-RNAi-lentivirus,while negative control group mice were injected with the same dose of negative-lentivirus.Tumor size was blindly measured every other day,and mRNA and protein expression levels of ObR,estrogen receptor α(ERα),and vascular endothelial growth factor (VEGF) for each group were determined.Results Knockdown of ObR-treated xenografted nude mice with a high leptin microenvironment was successfully established.Local injection of ObR-RNAi-lentivirus significantly suppressed the established tumor growth in nude mice.ObR level was significantly lower in the experimental group than in the negative control group,while the amounts of ERα and VEGF expression were significantly lower in the leptin group than in the control group (P <0.01 for all).Conclusions Inhibition of leptin/ObR signaling is essential to breast cancer proliferation and possible crosstalk between ObR and ERα,and VEGF,and may lead to novel therapeutic treatments aiming at targeting ObR in breast cancers.

  18. Effects of leptin on in vitro maturation, fertilization and embryonic cleavage after ICSI and early developmental expression of leptin (Ob and leptin receptor (ObR proteins in the horse

    Directory of Open Access Journals (Sweden)

    Arrighi Silvana

    2009-10-01

    Full Text Available Abstract Background The identification of the adipocyte-derived obesity gene product, leptin (Ob, and subsequently its association with reproduction in rodents and humans led to speculations that leptin may be involved in the regulation of oocyte and preimplantation embryo development. In mice and pigs, in vitro leptin addition significantly increased meiotic resumption and promoted preimplantation embryo development in a dose-dependent manner. This study was conducted to determine whether leptin supplementation during in vitro maturation (IVM to horse oocytes could have effects on their developmental capacity after fertilization by IntraCytoplasmic Sperm Injection (ICSI. Methods Compact and expanded-cumulus horse oocytes were matured in medium containing different concentrations (1, 10, 100, 1000 ng/ml of recombinant human leptin and the effects on maturation, fertilization and embryo cleavage were evaluated. Furthermore, early developmental expression of Ob and leptin receptor (Ob-R was investigated by immunocytochemical staining. Results In expanded-cumulus oocytes, the addition of leptin in IVM medium improved maturation (74% vs 44%, for 100 ng/ml leptin-treated and control groups, respectively; P Conclusion Leptin plays a cumulus cell-mediated role in the regulation of oocyte maturation in the mare. Species-specific differences may exist in oocyte sensitivity to leptin.

  19. Stability, elastic and magnetostrictive properties of γ-Fe{sub 4}C and its derivatives from first principles theory

    Energy Technology Data Exchange (ETDEWEB)

    Zhang, Yun; Wang, Zhe [Department of Physics, Xiangtan University, Xiangtan, 411105 Hunan (China); Cao, Juexian, E-mail: jxcao@xtu.edu.cn [Department of Physics, Xiangtan University, Xiangtan, 411105 Hunan (China); Beijing Computational Science Reasearch Center, 100084 Beijing (China)

    2014-11-15

    Using the first-principles full-potential linearized augmented plane-wave method, we investigated the stability, elastic and magnetostrictive properties of γ-Fe{sub 4}C and its derivatives. From the formation energy, we show that the most preferable configuration for MFe{sub 3}C (M=Pd, Pt, Rh, Ir) is that the M atom occupies the corner 1a position rather than 3c position. These derivatives are ductile due to high B/G values except for IrFe{sub 3}C. The calculated tetragonal magnetostrictive coefficient λ{sub 001} value for γ-Fe{sub 4}C is −380 ppm, which is larger than the value of Fe{sub 83}Ga{sub 17} (+207 ppm). Due to the strong SOC coupling strength constant (ξ) of Pt, the calculated λ{sub 001} of PtFe{sub 3}C is −691 ppm, which is increased by 80% compared to that of γ-Fe{sub 4}C. We demonstrate the origin of giant magnetostriction coefficient in terms of electronic structures and their responses to the tetragonal lattice distortion. - Highlights: • The most preferable site for M atom of MFe{sub 3}C (M=Pd, Pt, Rh, Ir) is the corner position. • The magnetostrictive coefficient for γ-Fe{sub 4}C is −380 ppm, larger than the value of Fe{sub 83}Ga{sub 17}. • The calculated λ{sub 001} of PtFe{sub 3}C is −691 ppm, which is increased by 80% compared to that of γ-Fe{sub 4}C.

  20. Study on the Blistering of B4C/Al Neutron Absorber Plate in the Course of Corrosion%B4C/Al中子吸收板腐蚀过程中的起泡研究

    Institute of Scientific and Technical Information of China (English)

    李刚; 王美玲; 王贯春; 简敏

    2012-01-01

    The corrosion model of cladding blistering on B4C/A1 neutron absorber plate was established by Henry's law, and by means of the model to investigate the relationship between pore radius and temperature factors for blistering. Influence of pore size for the neutron absorber plate blistering was analyzed by using the pore capillary effects. The results show that the hydrogen pressure produced in small radius pores is higher due to Al corrosion, which contributed to B4C/A1 neutron absorber plate cladding blistering. Influence of temperature on the corrosion generated hydrogen pressure is very small, but the main factors affecting the hydrogen pressure is the pore radius sizes. Blistering power of the cladding is hydrogen continuous generation and accumulating in the pore capillary. The water diffuses easily through the pore capillary in B4C/A1 cores, which will cause the cladding blistering because of Al corrosion.%根据亨利定律,建立了B4C/Al中子吸收板包壳腐蚀起泡的模型,计算了孔隙半径、温度对起泡的影响,并利用孔隙毛细管效应分析了孔隙对中子吸收板起泡的影响.结果表明:孔隙半径越小,腐蚀产生的氢气压力越大,B4C/Al中子吸收板包壳更易起泡;温度对腐蚀产生的氢气压力影响非常小,而孔隙半径是影响氢气压力的主要因素;氢气持续产生并在孔隙毛细管中积聚,是包壳产生起泡的动力;水分容易通过孔隙毛细管在B4C/Al芯体中扩散,可导致Al腐蚀,引起包壳起泡.

  1. 海底地震仪数据处理方法及其在海洋油气资源探测中的发展趋势%Data processing methods of OBS and its development tendency in detection of offshore oil and gas resources

    Institute of Scientific and Technical Information of China (English)

    刘丽华; 吕川川; 郝天珧; 游庆瑜; 郑彦鹏; 支鹏遥; 潘军; 刘少华

    2012-01-01

    The technology of ocean bottom seismograph (OBS) was an newly developed geophysics technology! and it was mainly used in the monitoring of ocean seismic, the surveying of ocean bottom structure and the detection of offshore oil and gas. The prospect of this technology is closely linked with the development of OBS instrument and the progress of OBS data processing. Presently, the processing of OBS data mainly uses the wide-angle seismic sounding data processing method, complementary with natural seismic tomography imaging technology, and eventually inversed the deep velocity structure. This paper makes a simple summarization on the evolution of OBS at the beginning; then introduces the data processing methods of OBS in detail, such as spectrum analysis and its application; environment noise analysis; gain, band-pass filtering, deconvolution and some other conventional processing; time correction; seismic phase picking and inversion methods, based on the instance of the OBS data processing of Bohai onshore-offshore seismic survey in 2010 and 2011 and the development on OBS data processing achieved by some other scholars. Furthermore, this paper makes a discussion on the application and the development tendency of OBS in the detection of offshore oil and gas. Through the spectrum analysis, we found that the advantage frequency band of air gun signal is 3-15 Hz, and the near offset spectrum of vertical component of OBS record can objectively reflect whether the OBS and the sea floor are well coupled with each other. While through the noise analysis, we found that the noise strength will decrease when depth and offset increase, and noise level is closely related to the sedimentary environment. This article thinks that OBS data processing and platform construction still have a long way to go, and they are one of the key link in the introduction of OBS to exploration of oil-gas resources earlier, which need much more forward research work.%海底地震仪(Ocean Bottom

  2. Adipokines : rôle dans l’obésité et l’insulino‐résistance

    Directory of Open Access Journals (Sweden)

    Aubert Roberte

    2003-03-01

    Full Text Available Le tissu adipeux longtemps considéré comme un organe de stockage est maintenant reconnu comme un organe endocrine. Cette revue étudie l’action de 3 adipokines sécrétées par le tissu adipeux et impliquées dans le contrôle de l’homéostasie énergétique et l’insulino‐résistance, la leptine, l’adiponectine et la résistine. La découverte de la leptine a permis la compréhension des mécanismes centraux de la prise alimentaire et de la dépense énergétique. L’espoir que la leptine puisse intervenir dans le traitement de l’obésité a été déçu, mais elle joue un rôle important dans l’insulino‐sensibilité. L’adiponectine circulante est diminuée dans l’obésité et la perte pondérale augmente son taux. Elle améliore la sensibilité à l’insuline en agissant sur le métabolisme glucidique et lipidique. Bien que pour le moment le rôle de la résistine soit encore mal défini, les études chez l’animal suggèrent qu’elle soit impliqués dans l’insulino‐résistance. Chez l’homme il n’y a pas de relation entre l’expression de la résistine et l’obésité. On peut donc se demander si la résistine, dans l’espèce humaine, est bien le lien entre obésité et diabète de type 2.

  3. Application of flood index in monitoring Flood-plain ecosystems (by the example of the Middle Ob flood-plain)

    OpenAIRE

    Bolotnov, V. P.

    2007-01-01

    The concept of regional hydroecological monitoring has been developed for the flood-plain of the Middle Ob. Its object is to control the state of flood-plain ecosystem productivity for organization of scientific, regional-adopted and ecologically regulated nature management. For this purpose hydroecological zoning of flood-plain territory performed, the most representative stations of water-gauge observations for each flood-plain zone organized, the scheme of flood-plain flooding was prepared...

  4. Triggering risk factors of the burnout syndrome in OB/GYN physicians from a reference public university of Brazil.

    Science.gov (United States)

    Ferreira Bortoletti, Fátima; Teresa Benevides-Pereira, Ana Maria; Vasconcellos, Esdras Guerreiro; Siqueira, José Oliveira; Araujo Júnior, Edward; Nardozza, Luciano Marcondes Machado; Sebastiani, Ricardo Werner; Moron, Antonio Fernandes

    2012-01-01

    Objective. To identify the risk factors to the development of Burnout Syndrome in Ob/Gyn Brazilian physicians in four dimensions: emotional exhaustion (EE), professional repression (PR), dehumanization (De), and emotional distancing (EmD). Methods. A prospective cross-sectional study was realized with 48 Ob/Gyn physicians (12 lecturers, 12 attending physicians, 12 medical residents, and 12 graduate students) from Department of Obstetrics, São Paulo Federal University (UNIFESP). We used a sociodemographic questionnaire focusing on the activities (administrative, educational, healthcare, and research). We applied a Burnout Syndrome Inventory (BSI) composed of two parts: triggering factors (ISB1) and the Burnout Syndrome (ISB2). The ISB1 is composed of two scales: positive organizational conditions (POC) and negative organizational conditions (NOC). The ISB2 is composed of four scales: EE, PR, De, and EmD. Results. We observed a rate below and above average to POC and NOC, respectively. The dimensions recorded a level above average to EE, an index at the upper limit of the average to De, a median index to EmD, and a median index to PR. Conclusions. The Ob/Gyn physicians are in an area of vulnerability for the development of Burnout Syndrome due to the high level of EE and De, associated with a median index of PR. The high rate of NOC contributes to the triggering of this scenery.

  5. The massive eclipsing system ALS 1135 and variable stars in the field of the distant OB association Bochum 7

    CERN Document Server

    Michalska, G; Pigulski, A; Steslicki, M; Williams, A

    2012-01-01

    Using photometric and spectroscopic observations of the double-lined early-type eclipsing binary system ALS 1135, a member of the distant OB association Bochum 7, we derived the new physical and orbital parameters of its components. The masses of both components were derived with an accuracy better than 1 per cent, their radii, with an accuracy better than 3 per cent. Since the primary's mass is equal to about 25 sun masses, its radius was subsequently used to derive the age of the system which is equal to 4.3+/-0.5 Myr. The result shows that this method represents a viable alternative to isochrone fitting. A photometric search of the field of ALS 1135 resulted in the discovery of 17 variable stars, including seven pulsating ones. One of them is an SPB star belonging to Vel OB1, the other six are delta Scuti stars. Of the six delta Scuti stars three might belong to Vel OB1, the other two are likely members of Bochum 7. Given the age of Bochum 7, these two stars are probably pre-main sequence pulsators. In add...

  6. Effects of leptin on the expression of Ob-Rb mRNA in the cultured adipocytes of newborn calf

    Institute of Scientific and Technical Information of China (English)

    NIU Shuling; ZHANG Cai; XIA Cheng; WANG Zhe; LIANG Guansheng; XU Chuang

    2007-01-01

    The effects of additional leptin on the long type receptor (Ob-Rb mRNA) for adipocytes of new born calf were tested by means of competitive reverse transcription polymerase chain reaction (RT-PCR).A sample of fine monolayer adipose cells were first obtained and recombination leptins of calf (5 ng/mL.12 h) were added.No additive was adopted as tester in the adipose cell.Total RNA was determined at 4,12,24,36,48 and 72 h,and duplicated three times in every treatment in the single factor duplicating test.The result,compared with the group of testers,was that the quantity of Ob-Rb mRNA in adipose cell cultures was also significantly higher (P<0.01) at the beginning stage.Following this tendency,the quantity was gradually lower with cultured time going on in 12-24 h,and the quantity was in stable level (P>0.05) from 48 to 72 h.It was shown that leptin could improve the level of expression of Ob-Rb in cultured adipose cells of new born calf within a definite time.

  7. Photoevaporation and close encounters: how the environment around Cygnus OB2 affects the evolution of protoplanetary disks

    CERN Document Server

    Guarcello, M G; Wright, N J; Albacete-Colombo, J F; Clarke, C; Ercolano, B; Flaccomio, E; Kashyap, V; Micela, G; Naylor, T; Schneider, N; Sciortino, S; Vink, J S

    2016-01-01

    In our Galaxy, star formation occurs in a variety of environments, with a large fraction of stars formed in clusters hosting massive stars. OB stars have an important feedback on the evolution of protoplanetary disks around nearby young stars and likely on the process of planet formation occurring in them. The nearby massive association Cygnus OB2 is an outstanding laboratory to study this feedback. It is the closest massive association to our Sun, and hosts hundreds of massive stars and thousands of low mass members. In this paper, we analyze the spatial variation of the disk fraction in Cygnus OB2 and we study its correlation with the local values of Far and Extreme ultraviolet radiation fields and the local stellar surface density. We present definitive evidence that disks are more rapidly dissipated in the regions of the association characterized by intense local UV field and large stellar density. In particular, the FUV radiation dominates disks dissipation timescales in the proximity (i.e. within 0.5 pc...

  8. The Massive Star Forming Region Cygnus OB2. II. Integrated Stellar Properties and the Star Formation History

    CERN Document Server

    Wright, Nicholas J; Drew, Janet E; Vink, Jorick S

    2010-01-01

    Cygnus OB2 is the nearest example of a massive star forming region, containing over 50 O-type stars and hundreds of B-type stars. We have analysed the properties of young stars in two fields in Cyg OB2 using the recently published deep catalogue of Chandra X-ray point sources with complementary optical and near-IR photometry. Our sample is complete to 1 Msun (excluding A and B-type stars that do not emit X-rays), making this the deepest study of the stellar properties and star formation history in Cyg OB2 to date. From Siess et al. (2000) isochrone fits to the near-IR color-magnitude diagram, we derive ages of 3.5 (+0.75/-1.0) and 5.25 (+1.5/-1.0) Myrs for sources in the two fields, both with considerable spreads around the pre-MS isochrones. The presence of a stellar population somewhat older than the present-day O-type stars, also fits in with the low fraction of sources with inner circumstellar disks (as traced by the K-band excess) that we find to be very low, but appropriate for a population of age ~5 My...

  9. Quantitative variation in obesity-related traits and insulin precursors linked to the OB gene region on human chromosome 7

    Energy Technology Data Exchange (ETDEWEB)

    Duggirala, R.; Stern, M.P.; Reinhart, L.J. [Univ. of Texas Health Science Center, San Antonio, TX (United States)] [and others

    1996-09-01

    Despite the evidence that human obesity has strong genetic determinants, efforts at identifying specific genes that influence human obesity have largely been unsuccessful. Using the sibship data obtained from 32 low-income Mexican American pedigrees ascertained on a type II diabetic proband and a multipoint variance-components method, we tested for linkage between various obesity-related traits plus associated metabolic traits and 15 markers on human chromosome 7. We found evidence for linkage between markers in the OB gene region and various traits, as follows: D7S514 and extremity skinfolds (LOD = 3.1), human carboxypeptidase A1 (HCPA1) and 32,33-split proinsulin level (LOD = 4.2), and HCPA1 and proinsulin level (LOD = 3.2). A putative susceptibility locus linked to the marker D7S514 explained 56% of the total phenotypic variation in extremity skinfolds. Variation at the HCPA1 locus explained 64% of phenotypic variation in proinsulin level and {approximately}73% of phenotypic variation in split proinsulin concentration, respectively. Weaker evidence for linkage to several other obesity-related traits (e.g., waist circumference, body-mass index, fat mass by bioimpedance, etc.) was observed for a genetic location, which is {approximately}15 cM telomeric to OB. In conclusion, our study reveals that the OB region plays a significant role in determining the phenotypic variation of both insulin precursors and obesity-related traits, at least in Mexican Americans. 66 refs., 3 figs., 4 tabs.

  10. Effect of microstructure on low temperature electrochemical properties of LiFePO{sub 4}/C cathode material

    Energy Technology Data Exchange (ETDEWEB)

    Zhao, Nannan; Zhi, Xiaoke; Wang, Li; Liu, Yanhui; Liang, Guangchuan, E-mail: liangguangchuan@hebut.edu.cn

    2015-10-05

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO{sub 4}/C composites was discussed. A conclusion that cathode material is the main limitation for the low temperature performance was come up, by comparing the low temperature performance of 18650 Li-ion batteries with LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2} and LiFePO{sub 4}/C as cathode materials. The low temperature performance results indicate the LiFePO{sub 4}/C microstructure is the main factor influencing the low temperature performance of LiFePO{sub 4}. A new LiFePO{sub 4}/C with pomegranate-like spherical structure was proposed in this paper, which shows superior low temperature performance, which can be attributed to its uniform fine primary particles and smaller primary particles. - Highlights: • Low temperature performance of Li-ion battery and LiFePO{sub 4}/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO{sub 4}/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO{sub 4}/C has good low temperature performance. - Abstract: The low-temperature electrochemical performance of Li-ion batteries is mainly determined by the choice of cathode material, as evident from a comparison of the low-temperature electrochemical performance of the 18650 batteries with the LiMn{sub 2}O{sub 4}, LiNi{sub 1/3}Co{sub 1/3}Mn{sub 1/3}O{sub 2}, and LiFePO{sub 4}/C as the cathode, respectively, at −20 °C. LiFePO{sub 4}/C materials with different morphologies and microstructures were prepared by different methods. The samples were characterized by X-ray diffraction (XRD), scanning electron microscope (SEM), transmission electron microscope (TEM), galvanostatic charge–discharge measurements and EIS. The low-temperature performance of the samples and those of the coin cells utilizing the materials as cathodes were measured. The results

  11. Massive Variability Surveys from Venezuela

    CERN Document Server

    Briceño, C

    2003-01-01

    At the Venezuela National Astronomical Observatory we are carrying out variability surveys spanning many hundreds of square degrees near the celestial equator, using an 8k x 8k CCD Mosaic Camera optimized for drift-scanning on a 1m Schmidt telescope. Among the initial efforts was a project to obtain the first moderately deep, homogeneous sample of young stars over an area of ~180sqr.deg. encompassing the entire Orion OB1 association, one of the nearest and most active regions of star formation. The results show that variability is a powerful technique to identify pre-main sequence populations, specially in sparse areas devoid of gas and dust. We are currently developing a massive database, equipped with web-based data mining tools, that will make our data and results available to the astronomical community.

  12. EXPLORATION OF RESIDENTIAL AREA PLANNING IDEOLOGY FROM THE PERSPECTIVE OF 4C MARKETING THEORY%基于"4C"营销理论的居住区规划理念探索

    Institute of Scientific and Technical Information of China (English)

    任英; 李桂文; 詹雪红

    2007-01-01

    将"4C"营销理论引入居住区规划设计,认为在居住区规划时要从消费者的需求、消费者的成本、消费者的方便和沟通四个方面出发,才能规划出合理和人性化的居住空间.

  13. 高含量B4C/Al基复合材料磨损行为研究%Adhesive Wear Behavior of High Content B4C-Aluminium Metal Matrix Composite

    Institute of Scientific and Technical Information of China (English)

    张鹏; 张哲维; 陈洪胜; 王文先; 王保东

    2014-01-01

    对质量分数分别为20%、30%和40%的高含量B4C/Al基复合材料的磨损行为进行了研究,分析了颗粒含量、载荷变化以及磨损时间对该复合材料磨损性能的影响,探索了该复合材料磨损过程的微观机制.结果表明:B4C/Al基复合材料的磨擦系数随B4C含量的增加而减小,材料耐磨损性能随B4C硬质颗粒含量的增加而提高;随载荷从30 N增加到70 N,B4C/Al复合材料的磨擦系数先减小再增加,材料磨损速率随载荷增加而增大.随磨损进行,整个磨损过程体现出阶段性的变化,复合材料的摩擦系数先减小再增加,磨损速率先缓慢增大,然后较快增长.高含量B4C/Al基复合材料磨损过程主要表现为犁削磨损和黏着磨损的磨损方式,同时还伴随有氧化磨损机制.

  14. 4 C Theory and“Hercy Morning News” Distribution Marketing Strategy%4C 理论与《海西晨报》发行营销策略的构建

    Institute of Scientific and Technical Information of China (English)

    张涛

    2015-01-01

    从营销学看4C 营销理论,强调读者的中心地位,符合市场经济条件下报业经济发展的要求,4C营销理论对《海西晨报》社的发行营销策略具有重要启发。可以从生产读者欲求的报纸产品、降低读者满足阅读和购买需求的成本、提高读者阅读和购买报纸的方便程度、与读者加强沟通等四个方面进行设计和构想。%4C marketing theory emphasizes the central position of readers , to meet the requirements of the develop-ment of newspaper industry under the market economy condition .The 4C marketing theory has important inspiration to “Hercy Morning News” agency distribution marketing strategy .Specifically , it is from four aspects as issuing the newspaper for reader's desire , reducing reading cost , improving convenience of purchase , and strengthening com-munication with readers to design the marketing strategy .

  15. An Updated Look at Binary Characteristics of Massive Stars in the Cygnus OB2 Association

    Science.gov (United States)

    Kiminki, Daniel C.; Kobulnicky, Henry A.

    2012-05-01

    This work provides a statistical analysis of the massive star binary characteristics in the Cygnus OB2 association using radial velocity information of 114 B3-O5 primary stars and orbital properties for the 24 known binaries. We compare these data to a series of Monte Carlo simulations to infer the intrinsic binary fraction and distributions of mass ratios, periods, and eccentricities. We model the distribution of mass ratio, log-period, and eccentricity as power laws and find best-fitting indices of α = 0.1 ± 0.5, β = 0.2 ± 0.4, and γ = -0.6 ± 0.3, respectively. These distributions indicate a preference for massive companions, short periods, and low eccentricities. Our analysis indicates that the binary fraction of the cluster is 44% ± 8% if all binary systems are (artificially) assumed to have P power-law period distribution is extrapolated to 104 years, then a plausible upper limit for bound systems, the binary fraction is ~90% ± 10%. Of these binary (or higher order) systems, ~45% will have companions close enough to interact during pre- or post-main-sequence evolution (semi-major axis lsim4.7 AU). The period distribution for P power law owing to an excess of systems with periods around 3-5 days (0.08-0.31 AU) and a relative shortage of systems with periods around 7-14 days (0.14-0.62 AU). We explore the idea that these longer-period systems evolved to produce the observed excess of short-period systems. The best-fitting binary parameters imply that secondaries generate, on average, ~16% of the V-band light in young massive populations. This means that photometrically based distance measurements for young massive clusters and associations will be systematically low by ~8% (0.16 mag in the distance modulus) if the luminous contributions of unresolved secondaries are not taken into account.

  16. ALMA Observations of Circumstellar Disks in the Upper Scorpius OB Association

    Science.gov (United States)

    Barenfeld, Scott A.; Carpenter, John M.; Ricci, Luca; Isella, Andrea

    2016-08-01

    We present ALMA observations of 106 G-, K-, and M-type stars in the Upper Scorpius OB Association hosting circumstellar disks. With these data, we measure the 0.88 mm continuum and 12CO J = 3-2 line fluxes of disks around low-mass (0.14-1.66 M ⊙) stars at an age of 5-11 Myr. Of the 75 primordial disks in the sample, 53 are detected in the dust continuum and 26 in CO. Of the 31 disks classified as debris/evolved transitional disks, five are detected in the continuum and none in CO. The lack of CO emission in approximately half of the disks with detected continuum emission can be explained if CO is optically thick but has a compact emitting area (≲40 au), or if the CO is heavily depleted by a factor of at least ˜1000 relative to interstellar medium abundances and is optically thin. The continuum measurements are used to estimate the dust mass of the disks. We find a correlation between disk dust mass and stellar host mass consistent with a power-law relation of {M}{dust}\\propto {M}* 1.67+/- 0.37. Disk dust masses in Upper Sco are compared to those measured in the younger Taurus star-forming region to constrain the evolution of disk dust mass. We find that the difference in the mean of {log}({M}{dust}/{M}* ) between Taurus and Upper Sco is 0.64 ± 0.09, such that M dust/M * is lower in Upper Sco by a factor of ˜4.5.

  17. Crustal structure in Gulf of Mexico from OBS refraction and multichannel reflection data

    Energy Technology Data Exchange (ETDEWEB)

    Ibrahim, A.K.; Carye, J.; Latham, G.; Buffler, R.T.

    1981-07-01

    Results from 12 reversed refraction profiles each 110 km long have been combined with multichannel reflection data to produce a series of crustal structure sections across the Gulf of Mexico. The refraction data were collected using ocean bottom seismographs (OBS) and explosive charges ranging in size from 1 to 120 lb (0.45 to 54.42 kg). These data show as many as three layers of sedimentary rocks with total thickness between 5 and 9 km and layer velocities between 1.7 and 3.5 km/sec. Beneath most of the Gulf, this sedimentary section is underlain by a layer with velocity between 4.5 and 5.4 km/sec. The acoustic basement as defined by reflection data is confined within this layer. This basement layer, which may be the top of volcanic layer 2, is too thin to be detected in the refraction results. Beneath this layer in most of the deep Gulf is an oceanic crustal layer (layer 3), 3 to 6 km thick which thickens to about 12 km under the Mississippi fan and 10 km in the southeastern Gulf where it is interpreted to be transitional crust. Oceanic layer 3 has a velocity between 6.4 and 7.0 km/sec and overlies a mantle with velocity between 7.6 and 8.2 km/sec. The top of oceanic layer 3 was not observed on regional multichannel seismic profiles. These data confirm earlier refraction interpretation that most of the deep Gulf basin is underlain by an oceanic crustal layer flanked by transitional crust. This layer may have been formed by a mantle thermal event accompanied by a period of rapid sea-floor spreading. 16 figures, 1 table.

  18. Preparation and electrochemical properties of LiFePO4/C composite with network structure for lithium ion batteries

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The bare LiFePO4 and LiFePO4/C composites with network structure were prepared by solid-state reaction. The crystalline structures, morphologies and specific surface areas of the materials were investigated by X-ray diffractometry(XRD), scanning electron microscopy(SEM) and multi-point brunauer emmett and teller(BET) method. The results show that the LiFePO4/C composite with the best network structure is obtained by adding 10% phenolic resin carbon. Its electronic conductivity increases to 2.86×10-2 S/cm. It possesses the highest specific surface area of 115.65 m2/g, which exhibits the highest discharge specific capacity applied again.

  19. Synthesis and characterization of LiFePO4/C cathode materials by sol-gel method.

    Science.gov (United States)

    Liu, Shuxin; Yin, Hengbo; Wang, Haibin; Wang, Hong

    2014-09-01

    The carbon coated LiFePO4 cathode materials (LiFePO4/C) were successfully synthesized by sol-gel method with glucose, citric acid and PEG-4000 as dispersant and carbon source, respectively. The microstructure and grain size of LiFePO4/C composite were characterized by X-ray diffraction, Raman spectroscopy, transmission electron microscopy. The results showed that the carbon source and calcination temperature had important effect on the graphitization degree of carbon; the carbon decomposed by citric acid had higher graphitization degree; with calcination temperature rising, the graphitization degree of carbon increased and the particles size increased. The graphitization degree and grain size were very important for improving the electrochemical performance of LiFePO4 cathode materials, according to the experimental results, the sample LFP-700 (LFP-C) which was synthesized with citric acid as dispersant at 700 degree C had lower polarization and larger discharge capacity.

  20. Study of influence content of TiB{sub 2} by reaction in situ B{sub 4}C and TiC in mechanical properties on B4C ceramics; Estudo da infuencia do teor de TIB{sub 2}, obtido pela reacao in sutu de B{sub 4}C de TiC, nas propriedades mecanicas de ceramicas a base de B{sub 4}C

    Energy Technology Data Exchange (ETDEWEB)

    Coelho, M.L. Ramos; Bressiani, J.C. [Instituto de Pesquisa Energeticas e Nucleares (IPEN/CNEN-SP), Sao Paulo, SP (Brazil); Gomide, R.G.; Andrade, F.A. de, E-mail: maluraco@usp.br, E-mail: gomide@ctmsp.mar.mil.br, E-mail: fernando.andrade@ctmsp.mar.mil.br, E-mail: jbressia@ipen.br [Centro Tecnologico da Marinha em Sao Paulo (CTMS), Sao Paulo, SP (Brazil)

    2012-07-01

    The low density of ceramic materials promoted a change in research lines in the defense field. Research efforts and development directed to obtaining products of high density sintered of Al2O3, SiC and B4C, using different routes, both traditional as innovative, led to promising initial results, which justify the convergence of skills for the consolidation of research lines and the nationalization that sintered components of B4C with characteristics and properties compatible with the technical requirements established for the ballistic application. The low density of boron carbide (2.52 g/cm{sup 3}) gives in the final product a weight approximately 30% lower than armor made of alumina (3.96 g/cm{sup 3}). (author)

  1. Synthesis, Crystal Structure and Reactivity of (2,4-C7H11)2Yb*DME

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    (2,4-C7H11)2Yb*DME was synthesized by the reaction of YbCl3 with K(2,4-C7H11)(2,4-dimethylpentadienyl potassium), and the single crystal X-ray diffraction showed that the complex exists in a cis- staggered conformation. The crystal of the compound belongs to the monoclinic space group P21/n with a=0.875 2 (1) nm, b=1.490 6(1) nm, c=1.529 3(2) nm, β=97.55(2)°, V=1.977 79(4) nm3, Z=4, F(000)=735.8 e, μ=49.49 cm-1, R=0.033 and Rw=0.032. The title complex can be used as a catalyst for the polymerization of methyl methacrylate(MMA).

  2. Preparation and electrochemical properties of LiFePO4/C composite cathodes for lithium-ion batteries

    Indian Academy of Sciences (India)

    Han Chen; Shao-Chang Han; Wen-Zhi Yu; Hong-Zhi Bo; Chang-Ling Fan; Zhong-Yu Xu

    2006-12-01

    Three kinds of LiFePO4/C composites for lithium-ion batteries were prepared by solid-state reaction. The crystalline structure, morphology and specific surface area of the composites were investigated by X-ray diffraction, scanning electron microscopy and multi-point Brunauer, Emmett and Teller. The results showed that the samples were all well-ordered olivine structures. A network structure, LiFePO4/C composite, was obtained using phenolic resin as carbon source. It possessed the highest specific surface area of 115.65 m2/g, exhibited the highest discharge capacity of 164.89 and 149.12 mAh/g at 0.1 C and 1 C rates, respectively. The discharge capacity was completely recovered when 0.1 C rate was applied again.

  3. Surface Nb-ALLOYING on 0.4C-13Cr Stainless Steel: Microstructure and Tribological Behavior

    Science.gov (United States)

    Yu, Shengwang; You, Kai; Liu, Xiaozhen; Zhang, Yihui; Wang, Zhenxia; Liu, Xiaoping

    2016-02-01

    0.4C-13Cr stainless steel was alloyed with niobium using double glow plasma surface alloying and tribological properties of Nb-alloyed steel such as hardness, friction and wear were measured. Effects of the alloying temperature on microstructure and the tribological behavior of the alloyed steel were investigated compared with untreated steel. Formation mechanisms of Nb-alloyed layers and increased wear resistance were also studied. The result shows that after surface Nb-alloying treatment, the 0.4C-13Cr steel exhibits a diffusion adhesion at the alloyed layer/substrate interface and improved tribological property. The friction coefficient of Nb-alloyed steel is decreased by about 0.3-0.45 and the wear rate after Nb-alloying is only 2-5% of untreated steel.

  4. Two-step infiltration of aluminum melts into Al-Ti-B4C-CuO powder mixture pellets

    Science.gov (United States)

    Zhang, Jingjing; Lee, Jung-Moo; Cho, Young-Hee; Kim, Su-Hyeon; Yu, Huashun

    2016-03-01

    Aluminum matrix composites with a high volume fraction of B4C and TiB2 were fabricated by a novel processing technique - a quick spontaneous infiltration process. The process combines a pressureless infiltration with the combustion reaction of Al-Ti-B4C-CuO in molten aluminum. The process is realized in a simple and economical way in which the whole process is performed in air in a few minutes. To verify the rapidity of the process, the infiltration kinetics was calculated based on the Washburn equation in which melt flows into a porous skeleton. However, there was a noticeable deviation from the calculated results with the experimental results. Considering the cross-sections of the samples at different processing times, a new infiltration model (two step infiltration) consisting of macro-infiltration and micro-infiltration is suggested. The calculated kinetics results in light of the proposed model agree well with the experimental results.

  5. Effects of Nb-doped on the structure and electrochemical performance of LiFePO{sub 4}/C composites

    Energy Technology Data Exchange (ETDEWEB)

    Ma, Zhipeng [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); Shao, Guangjie, E-mail: shaoguangjie@ysu.edu.cn [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China); State Key Laboratory of Metastable Materials Science and Technology, Qinhuangdao 066004 (China); Wang, Guiling; Zhang, Ying; Du, Jianping [Hebei Key Laboratory of Applied Chemistry, College of Environmental and Chemical Engineering, Yanshan University, Qinhuangdao 066004 (China)

    2014-02-15

    The olivine-type niobium doping Li{sub 1−x}Nb{sub x}FePO{sub 4}/C (x=0, 0.005, 0.010, 0.015, 0.025) cathode materials were synthesized via a two-step ball milling solid state reaction. The effects of Nb doping were charactered by X-ray diffraction (XRD), field-emission scanning electron microscopy (FE-SEM), galvanostatic intermittent titration technique (GITT), cyclic voltammetry (CV), electrochemical impedance spectra (EIS) and galvanostatic charge–discharge. It is found that Nb doping enlarges the interplanar distance of crystal plane parallel to [0 1 0] direction in LiFePO{sub 4}. In other words, it widens the one dimensional diffusion channels of Li{sup +} along the [0 1 0] direction. Electrochemical test results indicate that the Li{sub 0.99}Nb{sub 0.01}FePO{sub 4}/C composite exhibits the best electrochemical performance with initial special discharge capacity of 139.3 mA h g{sup −1} at 1 C rate. The present synthesis route is promising in making the solid state reaction method more practical for preparation of the LiFePO{sub 4} material. - Graphical abstract: The proper amount of Nb doping widens the one dimensional diffusion channels of Li{sup +} along the [0 1 0] direction. Display Omitted - Highlights: • The Nb doping LiFePO{sub 4}/C is prepared by a facile two-step ball milling solid state reaction. • The sample possesses the better high-rate performance. • The tap density of Li{sub 0.99}Nb{sub 0.01}FePO{sub 4}/C sample is 1.76 g cm{sup −3}.

  6. Formation mechanism of LiFePO 4/C composite powders investigated by X-ray absorption spectroscopy

    Science.gov (United States)

    Hsu, Kuei-Feng; Hu, Shao-Kang; Chen, Chinh-Hsiang; Cheng, Ming-Yao; Tsay, Sun-Yuan; Chou, Tse-Chuan; Sheu, Hwo-Shuenn; Lee, Jyh-Fu; Hwang, Bing-Joe

    The local structure and oxidation states for both the precursors and the LiFePO 4/C composite powders were investigated by X-ray absorption spectroscopy (XAS) to provide a deep insight into their formation mechanism. It was found that the local structure and oxidation states of the precursors and the synthesized LiFePO 4/C powders as well as the electrochemical properties of the synthesized powders were strongly influenced by the R ratio (R: molar ratio of citric acid to total metal ions). The oxidation states of iron ions of the precursors for R = 1 and 0.75 consist mainly of Fe(II) and traces of Fe(III). However, the oxidation state of iron ions of the precursor for R = 0.5 comprises mainly of Fe(III). The oxidation state of iron ions of all the synthesized powders is Fe(II). The structure of the precursors and the synthesized powders for R = 1 and 0.75 is more ordering than that for R = 0.5. It is in good agreement with the observation of the cation mixing obtained from the Riteveld analysis of the XRD data. The better the electrochemical performance is, the more ordering the structure or the less the cation mixing. However, the effect of the R values on the carbon content is also essential for the electrochemical properties of the synthesized LiFePO 4/C composite powders. Increasing the carbon content leads to the increase in the electronic conductivity but impedes the Li + ion diffusion of the composite materials. Consequently, the powders synthesized at the optimal R ratio of 0.75 exhibited the highest initial capacity, about 150 mAh g -1 when cycled at 1/40 C rate at room temperature. The structural scheme of the precursors and the synthesized powders and the formation mechanism of the LiFePO 4/C composite powders are also addressed in this work.

  7. Characterization of Nanocrystallizatin Surface Layer of 0.4C-1Cr Low Alloy Steel Prepared by Ultrasonic Particulate Peening

    Institute of Scientific and Technical Information of China (English)

    ZHANG Jun-bao; LIU Yu-liang; ZHAO Xin-qi; WU Jie; SONG Hong-wei; XIONG Tian-ying

    2004-01-01

    A nanostructured surface layer was fabricated in a quenched and tempered 0.4C-1Cr low alloy steel by ultrasonic particulate peening technique. The microstructure of the nanocrystalline surface layer was characterized by means of TEM and Mossbauer spectroscopy. Experimental results reveal that both cementite and ferrite nanocrystals with an average size of 5 nm were formed in the surface layer of the steel, phase transformation of austenite and dissolution of cementite maybe occur in the process of ultrasonic particulate peening.

  8. Characterization of Nanocrystallizatin Surface Layer of 0.4C-1Cr Low Alloy Steel Prepared by Ultrasonic Particulate Peening

    Institute of Scientific and Technical Information of China (English)

    ZHANGJun-bao; LIUYu-liang; ZHAOXin-qi; WUJie; SONGHong-wei; XIONGTian-ying

    2004-01-01

    A nanostructured surface layer was fabricated in a quenched and tempered 0.4C-ICr low alloy steel by ultrasonic particulate peening technique. The microstructure of the nanocrystalline surface layer was characterized by means of TEM and Moessbauer spectroscopy. Experimental results reveal that both cementite and ferrite nanocrystals with an average size of 5 nm were formed in the surface layer of the steel, phase transformation of austenite and dissolution of cementite maybe occur in the process of ultrasonic particulate peening.

  9. Synthesis of Fe3O4/C/TiO2 Magnetic Photocatalyst via Vapor Phase Hydrolysis

    Directory of Open Access Journals (Sweden)

    Fuzhi Shi

    2012-01-01

    Full Text Available A core/multi-shell-structured Fe3O4/C/TiO2 magnetic photocatalyst is prepared via vapor phase hydrolysis process. The as-synthesized core/multi-shell-structured composite is characterized by X-ray diffraction (XRD, field emission scanning electron microscopy (FE-SEM, transmission electron microscopy (TEM, high-resolution electron microscopy (HRTEM, N2 adsorption-desorption isotherm analyses, vibrating sample magnetometer (VSM, and ultraviolet-visible (UV-Vis absorption spectroscopy. TEM and HRTEM show that well-crystallized anatase TiO2 nanocrystals are immobilized on the surface of as-prepared Fe3O4/C microspheres with dimensions around 200 nm. N2 adsorption-desorption isotherm analysis shows that the obtained photocatalyst exists disorderedly mesoporous structure. The photocatalytic efficiency of the catalyst in degradation of methylene blue is evaluated, and the Fe3O4/C/TiO2 photocatalyst with low TiO2 content (37% has a relatively higher activity than commercial anatase TiO2. The intermediate carbon layer avoids the photodissolution of Fe3O4 effectively, and the recycling property is largely improved due to the existence of magnetic Fe3O4 core.

  10. Learning Electrical Circuits: The Effects of the 4C-ID Instructional Approach in the Acquisition and Transfer of Knowledge

    Directory of Open Access Journals (Sweden)

    Mario Melo

    2015-07-01

    Full Text Available This study was designed to investigate the effects of two instructional approaches (4C-ID versus conventional on learners’ knowledge-acquisition and learning transfer of the electrical circuits content in Physics. Participants were 129 9th graders from a secondary school in Lisbon, M = 14.3 years, SD = 0.54. The participants were divided in two groups: an experimental group constituted three intact classes (n = 78; and a control group constituted two intact classes (n = 51. The experimental group was taught using a digital learning environment designed with the 4C-ID model principles while the control group learned the same contents through a conventional method. We assessed the students’ performance (knowledge-acquisition and transfer, the perceived cognitive load, and the instructional efficiency. Results indicated that the experimental group performed significantly better than the control group on a knowledge-acquisition test and in a learning transfer test. They also perceived a less cognitive load in the transfer test and the learning environment developed with the 4C-ID model proved to be more instructional efficient than the conventional method.

  11. A 100-kpc inverse Compton X-ray halo around 4C60.07 at z=3.79

    CERN Document Server

    Smail, Ian; Ivison, R J; Alexander, D M; Bower, R G; Stevens, J A; Geach, J E; Schärf, C A; Coppin, K E K; Van Breugel, W J M

    2009-01-01

    We analyse a 100-ks Chandra observation of the powerful radio galaxy, 4C60.07 at z=3.79. We identify extended X-ray emission with Lx~10^45 erg/s across a ~90-kpc region around the radio galaxy. The energetics of this X-ray halo and its morphological similarity to the radio emission from the galaxy suggest that it arises from inverse Compton (IC) scattering, by relativistic electrons in the radio jets, of Cosmic Microwave Background photons and potentially far-infrared photons from the dusty starbursts around this galaxy. The X-ray emission has a similar extent and morphology to the Ly-alpha halo around the galaxy, suggesting that it may be ionising this halo. Indeed we find that the GHz-radio and X-ray and Ly-alpha luminosities of the halo around 4C60.07 are identical to those of 4C41.17 (also at z=3.8) implying that these three components are linked by a single physical process. This is only the second example of highly-extended IC emission known at z>3, but it underlines the potential importance of IC emiss...

  12. Enhancement of thermal neutron attenuation of nano-B{sub 4}C, -BN dispersed neutron shielding polymer nanocomposites

    Energy Technology Data Exchange (ETDEWEB)

    Kim, Jaewoo, E-mail: kimj@kaeri.re.kr [Nuclear Materials Research Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); WCI Quantum Beam based Radiation Research Center, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Missouri University Research Reactor, University of Missouri-Columbia, Columbia, MO 65211 (United States); Lee, Byung-Chul [Nuclear Reactor Core Design Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Uhm, Young Rang [Radioisotopes Research Division, Korea Atomic Energy Research Institute, 111-989 Daeduck-daero, Yuseong-gu, Daejeon-si 305-353 (Korea, Republic of); Miller, William H. [Missouri University Research Reactor, University of Missouri-Columbia, Columbia, MO 65211 (United States)

    2014-10-15

    Highlights: • Preparation of B{sub 4}C and BN nanopowders using a simple ball milling process. • Homogeneous dispersion and strong adhesion of nano-B{sub 4}C and -BN with polymer matrix. • Enhancement of mechanical properties of the nanocomposites compared to their micro counterparts. • Enhancement of thermal neutron attenuation of the nanocomposites. - Abstract: Nano-sized boron carbide (B{sub 4}C) and boron nitride (BN) powder were prepared using ball milling. Micro- and milled nano-powders were melt blended with high density polyethylene (HDPE) using a polymer mixer followed by hot pressing to fabricate sheet composites. The tensile and flexural strengths of HDPE nanocomposites were ∼20% higher than their micro counterparts, while those for latter decreased compared to neat HDPE. Thermal neutrons attenuation of the prepared HDPE nanocomposites was evaluated using a monochromatic ∼0.025 eV neutron beam. Thermal neutron attenuation of the HDPE nanocomposites was greatly enhanced compared to their micro counterparts at the same B-10 areal densities. Monte Carlo n-Particles (MCNP) simulations based on the lattice structure modeling also shows the similar filler size dependent thermal neutron absorption.

  13. Impact of incorporation of chromium on electrochemical properties of LiFePO4/C for Li-ion batteries

    Directory of Open Access Journals (Sweden)

    Naik Amol

    2015-12-01

    Full Text Available LiFe0.95Cr0.05PO4/C was successfully synthesized by one-step solid-state reaction using a single mode microwave reactor. The effect of incorporation of chromium on LiFePO4 lattice parameters was systematically investigated by X-ray diffraction. Surface analysis was done by scanning electron microscopy and transmission electron microscopy. The ratio of amorphous to graphitic carbon was determined from Raman spectroscopic data. The influence of chromium incorporation on electrochemical properties was studied by recording charge/discharge cycles combined with electrochemical impedance spectroscopy (EIS and cyclic voltammetry. It was found that Cr incorporation significantly enhanced the electrochemical performance of LiFePO4 at all current densities up to 10 C. LiFe0.95Cr0.05PO4/C prepared exhibited the best performance with an initial specific discharge capacity of 157.7, 144.8, 138.3, 131.0, 124.1 and 111.1 mAh·g−1 at 0.1 C, 0.5 C, 1.0 C, 2.0 C, 5 C and 10 C, respectively. The doped sample displayed excellent capacity retention, which was substantially superior than that of pristine LiFePO4/C at a higher current rate.

  14. Effect of carbon source on the morphology and electrochemical performances of LiFePO4/C nanocomposites.

    Science.gov (United States)

    Liu, Shuxin; Wang, Haibin; Yin, Hengbo; Wang, Hong; He, Jichuan

    2014-03-01

    The carbon coated LiFePO4 (LiFePO4/C) nanocomposites materials were successfully synthesized by sol-gel method. The microstructure and morphology of LiFePO4/C nanocomposites were characterized by X-ray diffraction, Raman spectroscopy and scanning electron microscopy. The results showed that the carbon layers decomposed by different dispersant and carbon source had different graphitization degree, and the sugar could decompose to form more graphite-like structure carbon. The carbon source and heat-treatment temperature had some effect on the particle size and morphology, the sample LFP-S700 synthesized by adding sugar as carbon source at 700 degrees C had smaller particle size, uniform size distribution and spherical shape. The electrochemical behavior of LiFePO4/C nanocomposites was analyzed using galvanostatic measurements and cyclic voltammetry (CV). The results showed that the sample LFP-S700 had higher discharge specific capacities, higher apparent lithium ion diffusion coefficient and lower charge transfer resistance. The excellent electrochemical performance of sample LFP-S700 could be attributed to its high graphitization degree of carbon, smaller particle size and uniform size distribution.

  15. Nd sub 2 Fe sub 1 sub 4 C processed by the hydrogenation, disproportionation, desorption and recombination (HDDR) process

    CERN Document Server

    Sui, Y C; Liu, W; Xiao, Q F; Zhao, X G; Zhao, T; Chuang, Y C

    1998-01-01

    The hydrogenation, disproportionation, desorption and recombination (HDDR) process has been employed to produce Nd sub 2 Fe sub 1 sub 4 C-based permanent magnets. The master alloys for HDDR are Nd sub 2 Fe sub 1 sub 4 C-based alloys which are obtained by annealing mechanically alloyed (MA) Nd sub 1 sub 6 Fe sub 7 sub 5 C sub 9 powder at 850 deg. C. The disproportionation reaction at 850 deg. C results in the formation of an intimate mixture of Nd-hydride, alpha-Fe and Nd sub 2 Fe sub 2 C sub 3. On desorbing the hydrogen at the same temperature, different constituents recombine to form the thermodynamically stable Nd sub 2 Fe sub 1 sub 4 C and the Nd-rich phase, depending sensitively on recombination time and slightly on hydrogenation time. The phases obtained by HDDR at 950 deg. C consist of Nd sub 2 Fe sub 1 sub 7 C sub x , alpha-Fe, the Nd-rich phase and Nd sub 2 C sub 3 , whereas those obtained at 700 deg. C are of Nd sub 2 Fe sub 1 sub 7 C sub x , the Nd-rich phase and a small amount of alpha-Fe. For comp...

  16. Study of CaSO4-C-H2O System: Simulation Experiments and Thermodynamic Assessment%CaSO4-C-H2O体系研究:模拟实验与热力学探讨

    Institute of Scientific and Technical Information of China (English)

    丁康乐; 罗跃; 单敬福; 关富佳; 王莎莎

    2013-01-01

    It has been traditionally believed that the TSR solid bitumens (pyrobitumen) are the direct product of thermochemical process and has less effect over the process of thermochemical sulfate reduction (TSR) compared with hydrogen sulfide (H2S). In this study, thermochemical simulation experiment of the CaSO4-C-H2O system was conducted to investigate thermodynamic characteristics of STR in the CaSo4-C-H2O system using activated carbon (C) as a model compound of solid bitumen. The results show that CaSO4-C-H2O system initiated TSR process at the temperature of 300°C , generating products like CaCO3, H2S and CO2. The threshold temperature (300°C) is much lower than temperature range of the TSR simulation tests using hydrocarbons in both gaseous and aqueous states, and consistent with the result through thermodynamic calculations. Process simulation of TSR was conducted using the software of HSC Chemistry 5. 0. It was found that TSR in the CaSOf-C-H2O system initiated at reservoir temperatures of 25~200°C was completely controlled by kinetic factors and increasing pressure is unfavorable to initiation of TSR under a constant temperature. The intensity of TSR is likely associated with saturation concentration of CaSO4 in water: a small amount of water may contribute to better oxidizing conditions while excessive water likely restrains the process of TSR. Under the conditions of pH≤2 and certain temperature, amount of sulfate decreased with decreasing pH. However, for pH range (pH>4) formation water in sedimentary basins, effect of pH on TSR can be negligible. TSR in the system of CaSO4-C-H2O is an exothermic process, and the reaction heat increases with the increasing temperatures. It was established that reaction heat of TSR is about 12. 9-133 J/mol CaSO4 at 25~200°C. Thermodynamic studies and experimental results imply that solid bitumens (pyrobitumen) are much easily involved in TSR than gaseous or aqueous hydrocarbons.%传统认为TSR成因的固态沥青(焦

  17. Investigating the potential magnetic origin of wind variability in OB stars

    Science.gov (United States)

    David-Uraz, Alexandre

    2016-05-01

    In this thesis, the origin of large-scale structures in hot star winds, believed to be responsible for the presence of discrete absorption components (DACs) in the absorption troughs of ultraviolet resonance lines, is constrained using both observations and numerical simulations. These structures are understood as arising from bright regions on the stellar surface, although their physical cause remains unknown. First, we use high quality circular spectropolarimetric observations of 13 well-studied OB stars to evaluate the potential role of dipolar magnetic fields in producing DACs. We perform longitudinal field measurements and place limits on the field strength using Bayesian inference, assuming that it is dipolar. No magnetic field was detected within this sample. The derived constraints statistically refute any significant dynamical influence from a magnetic dipole on the wind for all of these stars, ruling out such fields as a cause for DACs. Second, we perform numerical simulations using bright spots constrained by broadband optical photometric observations. We calculate hydrodynamical wind models using three sets of spot sizes and strengths. Co-rotating interaction regions are yielded in each model, and radiative transfer shows that the properties of the variations in the UV resonance lines synthesized from these models are consistent with those found in observed UV spectra, establishing the first consistent link between UV spectroscopic line profile variability and photometric variations and thus supporting the bright spot paradigm (BSP). Finally, we develop and apply a phenomenological model to quantify the measurable effects co-rotating bright spots would have on broadband optical photometry and on the profiles of photospheric lines in optical spectra. This model can be used to evaluate the existence of these spots, and, in the event of their detection, characterize them. Furthermore, a tentative spot evolution model is presented. A preliminary analysis of

  18. Judging the Golden Shield Press's Rural Book Marketing from the "4C" Theory%从"4C"看金盾出版社的农村图书营销

    Institute of Scientific and Technical Information of China (English)

    黄超; 李苓

    2007-01-01

    顾客需求、购买成本、便利与沟通是中国出版产业挖掘和培养农村图书市场必须研究的四个关键性问题.本文以市场营销学中的"4C"理论对金盾出版社做的个案分析所折射出的农村图书营销智慧,对其他出版社有一定的示范效应.

  19. 从4P'S到4C'S:从传统营销到现代营销的转变%From 4p's to 4c's: the Shift from Traditional Marketing to Modern Marketing

    Institute of Scientific and Technical Information of China (English)

    于宝琴

    2001-01-01

    本文利用事实阐述了营销理念从4P'S到4C'S的变化.网络营销伴随着Internet和电子商务的发展而发生并发展起来.本文从多个方面说明了基于电子商务的营销特性、网络营销关键性的问题,指出了电子商务必将人类真正带入信息社会.

  20. Perpendicular magnetic anisotropy of FePt film on Si substrate with SiO{sub 2} underlayer and B{sub 4}C interlayers

    Energy Technology Data Exchange (ETDEWEB)

    Wang, H. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)], E-mail: nanoguy@126.com; Yang, F.J. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)], E-mail: yangfujun77@sina.com; Mo, Q.; Zhang, J.; Wang, H.B.; Wang, Y. [Faculty of Physics and Electronic Technology, Hubei University, Wuhan 430062 (China)

    2009-09-15

    FePt multilayer composite films with and without B{sub 4}C interlayer have been prepared by magnetron sputtering, respectively, and subsequent annealing in vacuum. It was found that the B{sub 4}C layers effectively serve as spacers to separate the FePt layers, enhancing (0 0 1) orientation of FePt alloy. Our results show that highly (0 0 1) oriented FePt/B{sub 4}C films have significant potential as perpendicular recording media.