WorldWideScience

Sample records for 4c obs survey

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

    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

    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.

  3. VizieR Online Data Catalog: Fourth Cambridge Survey (4C) (Pilkington+ 1965; Gower+ 1967)

    Pilkington, J. D. H.; Scott, P. F.

    1996-04-01

    The Fourth Cambridge Radio Survey (4C) Catalogue contains all survey data from the papers of Pilkington and Scott (1965MmRAS..69..183P) and Gower, Scott and Wills (1967MmRAS..71...49G). These data result from a survey of radio sources between declinations -07 and +80 degrees using the large Cambridge interferometer at 178 MHz. The computerized catalog contains for each source the 4C number, 1950 position, measured flux density, accuracy class, galactic coordinates, and remarks. For some sources miscellaneous brief comments such as cross identifications to the 3C catalog or remarks on contamination from nearby sources are given at the ends of the data records. A flag (*) is included if there are additional remarks in the published catalog. (1 data file).

  4. Technical development and scientific preparation for the e-MERLIN Cygnus OB2 radio survey

    Peck, L. W.

    2014-01-01

    e-MERLIN is a recent upgrade to the MERLIN radio array. This enhanced facility utilises recent developments in wide bandwidth receivers, a new WIDAR correlator, and a new optical fibre network. This upgrade provides an increase in sensitivity and image fidelity, but also results in a significant increase in data volume. This thesis is motivated by the Cygnus OB2 Radio Survey (COBRaS), an e-MERLIN Legacy project observing the core region of the largest OB association in the northern hemisphere...

  5. The CIDA Variability Survey of Orion OB1. I: the low-mass population of Ori OB 1a and 1b

    Briceño, C; Hernández, J; Vivas, A K; Hartmann, L; Downes, J J; Berlind, P; Briceno, Cesar; Calvet, Nuria; Hernandez, Jesus; Hartmann, Lee; Downes, Juan J.; Berlind, Perry

    2004-01-01

    We present results of a large scale, multi-epoch optical survey of the Ori OB1 association, carried out with the QuEST camera at the Venezuela National Astronomical Observatory. We identify for the first time the widely spread low-mass, young population in the Orion OB1a and OB1b sub-associations. Candidate members were picked up by their variability in the V-band and position in color-magnitude diagrams. We obtained spectra to confirm membership. In a region spanning ~ 68 deg^2 we found 197 new young stars; of these, 56 are located in the Ori OB1a subassociation and 142 in Ori OB1b. Comparison with the spatial extent of molecular gas and extinction maps indicates that the subassociation Ori 1b is concentrated within a ring-like structure of radius ~2 deg (~15 pc at 440 pc), centered roughly on the star epsilon Ori in the Orion belt. The ring is apparent in 13CO and corresponds to a region with an extinction Av>=1. The stars exhibiting strong Ha emission, an indicator of active accretion, are found along this...

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

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

    2016-04-01

    Context. The ESO public survey VISTA Variables in the Vía Láctea (VVV) has contributed with deep multi-epoch photometry of the Galactic bulge and the adjacent part of the disk over 526 sq. deg. More than a hundred cluster candidates have been reported thanks to this survey. Aims: 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. Methods: To characterize the clusters, we used near-infrared photometry (J, H, and KS) 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. Results: 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)×102 M⊙ and (4.17+4.15-2.08)×103 M⊙. We observed a relation between the clusters total mass Mecl and the mass of their most massive stellar member mmax, for clusters with an age <10 Myr. Based on observations taken within the ESO VISTA Public Survey VVV (programme ID 179.B-2002), and with ISAAC/VLT (programme 087.D-0341(A)).

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

    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 ...

  8. New massive X-ray binary candidates from the ROSAT Galactic Plane Survey I - Results from a cross-correlation with OB star catalogues

    Motch, C.; Haberl, F.; Dennerl, K.; Pakull, M.; Janot-Pacheco, E.

    1996-01-01

    We report the discovery of several new OB/X-ray accreting binary candidates. These massive systems were found by cross-correlating in position SIMBAD OB star catalogues with the part of the ROSAT all-sky survey located at low galactic latitudes (|b| 10^31 erg/s. Fol...

  9. Infrared properties of Active OB stars in the Magellanic Clouds from the Spitzer SAGE Survey

    Bonanos, A. Z.; Lennon, D.J.; Massa, D. L.; Sewilo, M.; Köhlinger, F.; Panagia, N.; van Loon, J. Th.; Evans, C. J.; Smith, L J; Meixner, M.; Gordon, K; teams, the SAGE

    2010-01-01

    We present a study of the infrared properties of 4922 spectroscopically confirmed massive stars in the Large and Small Magellanic Clouds, focusing on the active OB star population. Besides OB stars, our sample includes yellow and red supergiants, Wolf-Rayet stars, Luminous Blue Variables (LBVs) and supergiant B[e] stars. We detect a distinct Be star sequence, displaced to the red, and find a higher fraction of Oe and Be stars among O and early-B stars in the SMC, respectively, when compared t...

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

    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

  11. TOWARD COMPLETE STATISTICS OF MASSIVE BINARY STARS: PENULTIMATE RESULTS FROM THE CYGNUS OB2 RADIAL VELOCITY SURVEY

    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 days, but it is not scale-free. Inflections in the cumulative distribution near 6 days, 14 days, and 45 days suggest key physical scales of ≅0.2, ≅0.4, and ≅1 A.U. where yet-to-be-identified phenomena create distinct features. No single 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 ≲ 25 days 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 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

  12. TOWARD COMPLETE STATISTICS OF MASSIVE BINARY STARS: PENULTIMATE RESULTS FROM THE CYGNUS OB2 RADIAL VELOCITY SURVEY

    Kobulnicky, Henry A.; Lundquist, Michael J.; Burke, Jamison; Chapman, James; Keller, Erica; Lester, Kathryn; Rolen, Emily K.; Topel, Eric; Bhattacharjee, Anirban; Smullen, Rachel A.; Álvarez, Carlos A. Vargas; Runnoe, Jessie C.; Dale, Daniel A.; Brotherton, Michael M. [Department of Physics and Astronomy, University of Wyoming, Laramie, WY 82070 (United States); Kiminki, Daniel C., E-mail: chipk@uwyo.edu, E-mail: jburke2@swarthmore.edu, E-mail: jc6380@mcla.edu, E-mail: kelle22e@mtholyoke.edu, E-mail: kvl214@lehigh.edu, E-mail: emily.k.rolen@vanderbilt.edu, E-mail: topel@stolaf.edu [Department of Astronomy, University of Arizona, Tucson, AZ 85721 (United States)

    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 < 45 days, but it is not scale-free. Inflections in the cumulative distribution near 6 days, 14 days, and 45 days suggest key physical scales of ≅0.2, ≅0.4, and ≅1 A.U. where yet-to-be-identified phenomena create distinct features. No single 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 ≲ 25 days 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 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{sup –1} attributed to atmospheric fluctuations.

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

    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...

  14. OB Stellar Associations in the Large Magellanic Cloud Survey of young stellar systems

    Gouliermis, D; Kontizas, E; Korakitis, R

    2003-01-01

    The method developed by Gouliermis et al. (2000, Paper I), for the detection and classification of stellar systems in the LMC, was used for the identification of stellar associations and open clusters in the central area of the LMC. This method was applied on the stellar catalog produced from a scanned 1.2m UK Schmidt Telescope Plate in U with a field of view almost 6.5 deg x 6.5 deg, centered on the Bar of this galaxy. The survey of the identified systems is presented here followed by the results of the investigation on their spatial distribution and their structural parameters, as were estimated according to our proposed methodology in Paper I. The detected open clusters and stellar associations show to form large filamentary structures, which are often connected with the loci of HI shells. The derived mean size of the stellar associations in this survey was found to agree with the average size found previously by other authors, for stellar associations in different galaxies. This common size of about 80 pc...

  15. A high angular resolution survey of massive stars in Cygnus OB2: Results from the Hubble space telescope fine guidance sensors

    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 ΔV < 4 down to separations as small as 0.''01. The sample includes 58 of the brighter members of Cyg OB2, one of the closest examples of an environment containing a large number of very young and massive stars. We resolved binary companions for 12 targets and confirmed the triple nature of one other target, and we offer evidence of marginally resolved companions for two additional stars. We confirm the binary nature of 11 of these systems from complementary adaptive optics imaging observations. The overall binary frequency in our study is 22% to 26% corresponding to orbital periods ranging from 20 to 20,000 yr. When combined with the known short-period spectroscopic binaries, the results support the hypothesis that the binary fraction among massive stars is >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.

  16. Documentation for the machine-readable version of the Fourth Cambridge Radio Survey Catalogue (4C) (Pilkington, Gower, Scott and Wills 1965, 1967)

    Warren, W. H., Jr.

    1983-09-01

    The machine readable catalogue contains survey data from the papers of Pilkington and Scott and Gower, Scott and Wills. These data result from a survey of radio sources between declinations -07 deg and +80 deg using the large Cambridge interferometer at 178 MHz. The computerized catalog contains for each source the 4C number, 1950 position, measured flux density, and accuracy class. For some sources miscellaneous brief comments such as cross identifications to the 3C catalog or remarks on contamination from nearby sources are given at the ends of the data records. A detailed description of the machine readable catalog as it is currently being distributed by the Astronomical Data Center is given to enable users to read and process the data.

  17. 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

    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...

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

    Maíz Apellániz, J.; Evans, C. J.; 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.

    2014-04-01

    Context. The commonly used extinction laws of Cardelli et al. (1989, ApJ, 345, 245) have limitations that, among other issues, hamper the determination of the effective temperatures of O and early B stars from optical and near-infrared (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 and 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 and 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 uncertainties and only a small bias, at least up to E(4405-5495) ~ 1.5 mag. Appendices are available in electronic form at http://www.aanda.org

  19. The OBS Survey of Seismogenic Processes: Using 2010 Chile M=8.8 Mega Earthquake as example

    Lee, C.; Wei, H.; Wang, S.

    2012-12-01

    In the early morning of February 27, 2010, a mega-earthquake now known as the "Maule Earthquake" (M=8.8) took place in central Chile. In May 1960, Chile was hit by the largest earthquake ever recorded with a magnitude of 9.5. In general, the west coast of Chile is a convergent boundary between the Nazca and South American Plates, with the Nazca Plate subducting beneath the South American Plate in a NE direction. With a convergence rate of 6-7 cm per year, stress accumulates in the lower part of the oceanic plate to a certain extent resulting in huge destructive earthquakes. In 2010, our team deployed two OBS arrays (the A and B arrays), with a total of 33 deployments to record the aftershocks along the rupture area. We collected data for a total of 46 days (July 15 to August 7 for the A array and August 14 to September 6 for the B array). The aim of our study was to analyze the distribution and characteristics of the aftershocks to get a better understanding of the tectonic activity after the main event, and conjecture on the seismogenic processes that occurred during the rupture. Using the Antelope software on the data we picked the P- and S-wave arrivals and located the events. To obtain more accurate earthquake epicenter locations we also applied the HypoDD software. We recognized a total of 3,807 events in 46 days of monitoring (in average of 80 some earthquakes per day) with many of them distributed along both sides of the trench. Immediately behind the trench axis, along the frontal accretionary prism, there is an aseismic zone, possibly due to the high content of water in the sedimentary strata. On the other hand, the paleo-accretionary prism on the landward side of the trench accumulated most of the earthquakes. These events focus at depths of 50-100 km in the subduction zone. This is called the seismogenic zone. The comparison of events before the main shock and the HypoDD results of this study show that most of the events cluster along the edge of the

  20. Initial highlights of the HOBYS key program, the Herschel imaging survey of OB young stellar objects

    Motte, F; Zavagno, A.; Bontemps, S.; Schneider, N.; Hennemann, M.; Di Francesco, J.; André, Ph.; Saraceno, P.; Griffin, M; Marston, A.; Ward-Thompson, D.; White, G.; Minier, V.; Men'shchikov, A.; Hill, T.

    2010-01-01

    We present the initial highlights of the HOBYS key program, which are based on Herschel images of the Rosette molecular complex and maps of the RCW120 H II region. Using both SPIRE at 250/350/500 μm and PACS at 70/160 μm or 100/160 μm, the HOBYS survey provides an unbiased and complete census of intermediate- to high-mass young stellar objects, some of which are not detected by Spitzer. Key core properties, such as bolometric luminosity and mass (as derived from spectral energy distributions)...

  1. The 4C model

    Knox, Jeanette Bresson Ladegaard

    2014-01-01

    -care unit, my project was to develop a method that could stimulate systematically dialogical moral inquiry within everyday clinical practice. My four months of ethnographic fieldwork at the neonatal intensive-care unit generated four fundamental themes that make up the scaffold of the developed model for...... ethical deliberation and decision making. The model is a reflective tool to be used by health care professionals in situ. It provides a structured and a systematic framework for dialogue that can clarify the obscurities of a case and give argumentative support for ethical decisions. This article explains...... how the 4C model was developed and whereof it consists....

  2. Recent results on associations: anatomy of CMa OB1 and Mon OB1

    Three types of associations are presently recognized. These are OB, R, and T, and represent, respectively, concentrations of O and B-type stars, reflection nebulae, and T Tauri stars, in certain regions of the sky. OB and T associations are identified on objective prism plates; R associations may be found using direct plates such as those of the Palomar Sky Survey. All associations are intimately connected with what appear optically as dark clouds and are now detected as sources of molecular line emission and known as molecular clouds. Often, all three types of associations are found within the same cloud complex (eg. Mon OB1). However, there are also examples of T associations (Taurus) and R associations (Mon R2) which are not connected with recognized OB associations. (Auth.)

  3. Glucose metabolism and recycling by hepatocytes of OB/OB and ob/ob mice

    Hepatocytes were prepared from livers of ob/ob (obese diabetic) mice and their lean (OB/OB) siblings that had been fasted for 24 h. The hepatocytes were incubated with [U-14C, 2-3H]-, [U-14C, 3-3H]-, and [U-14C, 6-3H]glucose at concentrations from 20 to 120 mM. 14C was recovered mainly in CO2, glycogen, and lactate. Tritium was recovered in water and glycogen. The yield in labeled products from [2-3H]glucose ranged from two to three times that from [U-14C]glucose. The yields from [3-3H]- and [6-3H]glucose were similar, and 1.3-1.7 times that from [U-14C]glucose. At 40 mM, total utilization of glucose by obese mice was about twice that for lean mice, but there was little difference at 120 mM. The rate of recycling between glucose and glucose 6-phosphate was calculated. An equation to calculate the rate of recycling of glucose from the 2-3H/U-14C ratio in glycogen is derived in the APPENDIX. Our results show that (1) the utilization of glucose by hepatocytes from obese diabetic mice exceeds that of their lean controls, (2) the rate of glucose phosphorylation in both groups greatly exceeds glucose uptake and the rate of glycogen synthesis, (3) glucose phosphorylation represents a difference between a high glucokinase rate and hydrolysis of glucose 6-phosphate, and (4) recycling of glucose carbon between glucose 6-phosphate and pyruvate occurs within mouse hepatocytes

  4. Balanced {C_4, C_5}-Quatrefoil Systems

    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...

  5. Race and satisfaction in general OB/GYN clinics

    Rohrer James E; Lund Jon D; Goldfarb Susan

    2005-01-01

    Abstract Background The purpose of this study was to test the hypothesis that racial differences in satisfaction can be found among OB/GYN patients on a US naval base. Methods Cross-sectional surveys assessing satisfaction with services were obtained from 838 patients who were seen in one of the two general OB/GYN clinics (455 in the base hospital clinic and 391 in a satellite clinic). Multiple logistic regression analysis was used to identify subgroups of patients who were not very satisfied...

  6. Disk evolution in the Ori OB1 association

    Calvet, N; Hernández, J; Hoyer, S; Hartmann, L; Sicilia-Aguilar, A; Megeath, S T; D'Alessio, P; Calvet, Nuria; Briceno, Cesar; Hernandez, Jesus; Hoyer, Sergio; Hartmann, Lee; Sicilia-Aguilar, Aurora; Alessio, Paola D'

    2004-01-01

    We analyze multi-band photometry of a subsample of low mass stars in the associations Ori OB1a and 1b discovered during the CIDA Orion Variability Survey, which have ages of 7 - 10 Myr and 3 - 5 Myr, respectively. We obtained UBVRcIc photometry at Mt. Hopkins for 6 Classical T Tauri stars (CTTS) and 26 Weak T Tauri stars (WTTS) in Ori OB1a, and for 21 CTTS and 2 WTTS in Ori OB1b. We also obtained L band photometry for 14 CTTS at Mt. Hopkins, and 10um and 18um photometry with OSCIR at Gemini for 6 CTTS; of these, all 6 were detected at 10um while only one was detected at 18um. We estimate mass accretion rates from the excess luminosity at U, and find that they are consistent with determinations for a number of other associations, with or without high mass star formation. The observed decrease of mass accretion rate with age is qualitatively consistent with predictions of viscous evolution of accretion disks. We find an overall decrease of disk emission from Taurus to Ori OB1b to Ori OB1a. This decrease implies...

  7. A Search for Pulsar Companions to OB Runaway Stars

    Sayer, R. W.; Nice, D. J.; Kaspi, V. M.

    1996-04-01

    We have searched for radio pulsar companions to 40 nearby OB runaway stars. Observations were made at 575 and 770 MHz with the NRAO 140 foot (43 m) telescope. The survey was sensitive to long- period pulsars with flux densities of 1 mJy or more. No pulsar companions to OB runaways were discovered. One previously unknown pulsar was discovered, PSR J2044 +4614, while observing toward target 0 star BD +45°3260. Follow-up timing observations of the pulsar measured its position to high precision, revealing a 9' separation between the pulsar and the target star, unequivocally indicating they are not associated. The pulsar is ordinary, except that its dispersion measure, 315 pc cm-3, is unusually high given its Galactic longitude, l = 85°. The nondetection of pulsars bound to target stars places an upper limit of 8% (95% confidence) for the fraction of runaway OB stars with pulsar companions detectable via pulsed radio emission by surveys such as ours. Assuming standard models for the pulsar beaming fraction and luminosity function, we conclude most OB runaways do not have pulsar companions.

  8. Refraction Interferometry and Free-surface Multiples for Large-offset OBS Data

    Schuster, G. T.; Bharadwaj, P.; McIntosh, K.

    2011-12-01

    We present successful results for applying refraction interferometry to ocean bottom seismic (OBS) data. The OBS data were recorded by six inline OBS stations with a 15 km station spacing and a source ship shooting every 150 meters; the maximum source offset from an OBS station is 181 km. Each virtual trace was created by correlating and stacking up to 150 trace pairs to create a super-virtual refraction arrival having a theoretical signal-to-noise ratio (SNR) enhancement of up to 12:1. Free-surface refraction multiples were also utilized to enhance the SNR of primary refractions and virtually double the number of OBS sites from six to twelve stations. Results show the successful reconstruction of far-offset traces out to a source-receiver offset of 120 km. The super-virtual traces increase the number of pickable first arrivals from approximately 1,600 to more than 3,100 for a subset of the OBS data where the source is only on one side of the recording stations. In addition, the head waves associated with the first-order free-surface multiples allow for the creation of six new common receiver gathers (CRGs) recorded at virtual OBS stations, located about 5 km from any of the actual OBS stations. These new traces double the number of OBS stations compared to the original survey and increases the number of pickable traces from 1600 to 6200. In summary, our results with this OBS data set demonstrate that refraction interferometry can more than triple the number of pickable first arrivals in long-offset traces. This suggests the possibility that the number of independent OBS stations can be increased by N-fold if the free-surface refraction multiples up to the Nth-order are of high SNR and if the recording time is appropriately lengthened.

  9. Progress of homemade OBS and its application on ocean bottom structure survey%国产海底地震仪研制现状及其在海底结构探测中的应用

    郝天珧; 游庆瑜

    2011-01-01

    海底地震仪(Ocean Bottom Seismographs,OBS)及由其组成的海底流动地震观测台阵是近年来发展起来的高新技术,在油气探测、科学研究、防灾减灾等方面有广泛的用途,是地球物理仪器与探测技术发展中的一个新增长点.本文介绍了由中国科学院地质与地球物理研究所研制成功的宽频带、7通道海底地震仪((I-7C) OBS)的性能、指标以及关键技术的实现.同时,介绍了(I-7C) OBS近年来在渤海、南海以及西南印度洋的5次海上试验与应用的结果.5次应用试验中均有国外同类型的一起参加,(I-7C) OBS在性能指标、回收率和数据质量等方面都有较好的表现.2010年以来,国产OBS在我国各海区经过上百台次的海上作业(超过半数工作水深在2000m以上),仅丢失一台.仪器回收率超过98%,数据完整率超过950%.一些航次的首席科学家认为我国国产OBS已经达到国际先进水平.%Ocean Bottom Seismographs (OBS) and the seabed mobile seismic observation array composed by them was recently developed high-tech. It s a new growth point in the geophysical instruments and exploration technology, and it has a wide range of uses, such as in oil and gas exploration, scientific research, disaster prevention and mitigation and so on. The performance, technical data, and key techniques of the I-7C Ocean Bottom Seismograph (OBS) is introduced in this paper. The wideband 7-channel OBS is designed and produced by Institute of Geology and Geophysics, Chinese Academy of Sciences. In recent years we have conducted five marine tests in the Bohai Sea, South China Sea, and southwestern Indian Ocean. OBS instruments made in western countries were also used in the five tests. The results indicate the good performance of the (I-7C) OBS in technical data, recovery operation ratio, and data quality. Since 2010,homemade OBS were tested over one hundred times in different seas, more than half worked in over 2000 meters

  10. Black Rice with Giant Embryo Attenuates Obesity-Associated Metabolic Disorders in ob/ob Mice.

    Lee, Yoon-Mi; Han, Sank-Ik; Won, Yu-Jin; Lee, Eunji; Park, Eunju; Hwang, Seock-Yeon; Yeum, Kyung-Jin

    2016-03-30

    Obesity is closely associated with metabolic disorders such as hyperglycemia and dyslipidemia. Leptin-deficient ob/ob mice (C57BL/6J-ob/ob) and C57BL/6J mice were randomly assigned to a diet of black rice with giant embryo (BR), white rice (WR), or AIN-93G (control) and pair-fed for 14 weeks. Although there was no significant difference in body weight, BR-fed ob/ob mice had (1) significantly lower body fat mass than WR- and control-fed ob/ob mice determined by dual-energy X-ray absorptiometry; (2) significantly lower blood glucose, serum insulin, and triacylglycerol levels than control-fed ob/ob mice; and (3) significantly lower liver weight, hepatic triacylglycerol, and hepatic lipid droplets than both WR- and control-fed ob/ob mice. Furthermore, DNA damage in the liver, determined by phosphorylated H2AX protein, and in the kidney, determined by single-cell gel electrophoresis, was significantly lower in BR-fed than WR- and control-fed ob/ob mice. This study indicates that BR ameliorates obesity and its related metabolic disorders. PMID:26653400

  11. New OBS network deployment offshore Ireland

    Le Pape, Florian; Bean, Chris; Craig, David; Jousset, Philippe; Horan, Clare; Hogg, Colin; Donne, Sarah; McCann, Hannah; Möllhoff, Martin; Kirk, Henning; Ploetz, Aline

    2016-04-01

    With the presence of the stormy NE Atlantic, Ireland is ideally located to investigate further our understanding of ocean generated microseisms and use noise correlation methods to develop seismic imaging in marine environments as well as time-lapse monitoring. In order to study the microseismic activity offshore Ireland, 10 Broad Band Ocean Bottom Seismographs (OBSs) units including hydrophones have been deployed in January 2016 across the shelf offshore Donegal and out into the Rockall Trough. This survey represents the first Broadband passive study in this part of the NE Atlantic. The instruments will be recovered in August 2016 providing 8 months worth of data to study microseisms but also the offshore seismic activity in the area. One of the main goal of the survey is to investigate the spatial and temporal distributions of dominant microseism source regions, close to the microseism sources. Additionally we will study the coupling of seismic and acoustic signals at the sea bed and its evolution in both the deep water and continental shelf areas. Furthermore, the survey also aims to investigate further the relationship between sea state conditions (e.g. wave height, period), seafloor pressure variations and seismic data recorded on both land and seafloor. Finally, the deployed OBS network is also the first ever attempt to closely monitor local offshore earthquakes in Ireland. Ireland seismicity although relatively low can reduce slope stability and poses the possibility of triggering large offshore landslides and local tsunamis.

  12. New very massive stars in Cygnus OB2

    Negueruela, I.; Marco, A.; Herrero, A.; Clark, J. S.

    2008-08-01

    Context: The compact association Cygnus OB2 is known to contain a large population of massive stars, but its total mass is currently a matter of debate. While recent surveys have uncovered large numbers of OB stars in the area around Cyg OB2, detailed study of the optically brightest among them suggests that most are not part of the association. Aims: We observed an additional sample of optically faint OB star candidates, with the aim of checking if more obscured candidates are correspondingly more likely to be members of Cyg OB2. Methods: Low resolution spectra of 9 objects allow the rejection of one foreground star and the selection of four O-type stars, which were later observed at higher resolution. In a subsequent run, we observed three more stars in the classification region and three other stars in the far red. Results: We identify five (perhaps six) new evolved very massive stars and three main sequence O-type stars, all of which are likely to be members of Cyg OB2. The new findings allow a much better definition of the upper HR diagram, suggesting an age ~2.5 Myr for the association and hinting that the O3-5 supergiants in the association are blue stragglers, either younger or following a different evolutionary path from other cluster members. Though the bulk of the early stars seems to belong to an (approximately) single-age population, there is ample evidence for the presence of somewhat older stars at the same distance. Conclusions: Our results suggest that, even though Cyg OB2 is unlikely to contain as many as 100 O-type stars, it is indeed substantially more massive than was thought prior to recent infrared surveys. Figure [see full textsee full textsee full textsee full textsee full textsee full textsee full text] and Table [see full textsee full textsee full textsee full textsee full textsee full textsee full text] are only available in electronic form at http://www.aanda.org

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

    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 ...

  14. ZAZNANO TVEGANJE OB SPLETNEM NAKUPOVANJU

    Mihurko, Kaja

    2011-01-01

    Zaradi številnih prednosti, ki jih splet nudi, se število spletnih trgovin iz dneva v dan nenehno veča. Poznavanje vedenja kupcev pomaga izvajalcem marketinga pri prodobivanju in zaržanju kupcev. Zelo pomembno je tudi to, da se izvajalci marketinga zavedajo vloge, ki jo ima zaznavanje tveganje ob spletnem nakupovanju. V prvem teoretičnem delu je opisan pomen in prednosti spletnega poslovanja ter spletnega nakupovanja. Drugi del govori o vedenju kupcev na spletu, zadnji del pa o tveganju, ...

  15. Improved distances to several Galactic OB associations

    Kaltcheva, Nadia; Golev, Valeri

    2011-01-01

    Based on uvbybeta photometry we study the structure of several Galactic star-forming fields. Lac OB1 is a compact association at 520+/-20 pc spatially correlated with a region of intense HII emission in Sh2-126. Loden 112 is a compact OB group at 1630+/-82 pc, probably connected to an extended feature of OB stars located toward the Carina tangent. The field toward Car OB1 is complex and likely contains apparent concentrations representing parts of long segments of the Carina arm projected alo...

  16. Upregulated Expression of AQP 7 in the Skeletal Muscles of Obese ob/ob Mice

    Aquaporin (AQP) is suggested to be regulated by leptin through the phosphatidylinositol 3-kinase/Akt/mammalian target of rapamycin pathway. AQP7 and AQP9 are membrane proteins with water and glycerol channels, the latter of which is essential for triglyceride synthesis. We conjectured that the expression of AQP7 and AQP9 would be altered in the skeletal myofibers in obese leptin deficient ob/ob mice as compared with that of wild mice. RNA and protein levels were studied in the quadriceps femoris muscles of ob/ob and wild mice. Real time quantitative RT-PCR analysis showed that mouse AQP7 mRNA levels in skeletal muscles were significantly higher in ob/ob mice than in wild mice (P<0.01), whereas mouse AQP9 mRNA level was not different between the two groups (P>0.05). Histologically the type 1 myofibers of ob/ob mice contained numerous lipid droplets in oil red O stain samples. Immunohistochemical staining of ob/ob mouse muscles revealed enhanced expression of AQP7 at myofiber surface membranes, while AQP9 expression appeared to be similar to that of wild mice. The findings suggest that the upregulated expression of AQP7 in ob/ob mouse muscles facilitates the secretion of glycerol from myocytes

  17. The primordial binary population in ob associations

    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.

  18. Improved Distances to Several Galactic OB Associations

    Kaltcheva, N.; Golev, V.

    Based on uvbyBeta photometry we study the structure of several Galactic star-forming fields. Lac OB1 is a compact association at 520 ± 20 pc spatially correlated with a region of intense Hii emission in Sh2-126. Lodén 112 is a compact OB group at 1630 ± 82 pc, probably connected to an extended feature of OB stars located toward the Carina tangent. The field toward Car OB1 is complex and likely contains apparent concentrations representing parts of long segments of the Carina arm projected along the line of sight. Within the classical Mon OB2 association we separate a relatively compact group at 1.26 kpc, that is spatially correlated to the Monoceros Loop SN remnant.

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

    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.

  20. Chemical evolution of OB associations

    Schramm, D. N.; Olive, K. A.

    1982-01-01

    It is determined that the existence of Al-26 and Pd-107 in meteorites in the early solar system indicates that our solar system probably formed inside an OB association that had been contaminated by the debris of at least one supernova. In addition to these radioactive tracers, the contamination of the material out of which the solar system formed would have significantly enriched the heavy element composition of the solar system relative to that of the average interstellar medium. It is found that the solar system would be enriched in those isotopes which are produced by the more massive stars, such as O-16, C-12, Ne-20, and some other r-process material. It is proposed that specific isotopic ratios and elemental ratios reflecting these differences would include the Ne-20/Ne-22 ratio, which would be higher in the solar system than in the interstellar medium and the cosmic rays, the C-12/C-13 ratio which would be higher in the solar system than in the interstellar medium, and the oxygen-to-carbon ratio, which would also be higher in the solar system than in the typical interstellar medium.

  1. Sintering of boron carbide (B4C)

    Boron carbide (B4C) is used as a control element in different types of reactors due to the high fast and thermal neutron absorption cross-section of B-10. Requirements of the Advanced Reactor Division of the Bariloche Atomic Center triggered the study of the possibilities of fabricating B4C pellets by cold-pressing and sintering. The results of essays of sinterability of two different commercial boron carbide powders, sintered at temperatures between 1200 and 2200 deg C, are given. Characterizations of the samples were made to determine the evolution of density, porosity, microstructure and boron content as a function of sintering temperature. (Author)

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

    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.

  3. Preemption window for burst differentiation in OBS

    Klinkowski, Miroslaw; Careglio, Davide; Morató, Daniel; Solé Pareta, Josep

    2008-01-01

    This paper presents a novel control architecture for optical burst switching networks to efficiently apply burst preemption without the resources overbooking, which is specific to conventional OBS. Simulation results prove the effectiveness of this proposal.

  4. Differences in early acetaminophen hepatotoxicity between obese ob/ob and db/db mice.

    Aubert, Jacinthe; Begriche, Karima; Delannoy, Matthieu; Morel, Isabelle; Pajaud, Julie; Ribault, Catherine; Lepage, Sylvie; McGill, Mitchell R; Lucas-Clerc, Catherine; Turlin, Bruno; Robin, Marie-Anne; Jaeschke, Hartmut; Fromenty, Bernard

    2012-09-01

    Clinical investigations suggest that hepatotoxicity after acetaminophen (APAP) overdose could be more severe in the context of obesity and nonalcoholic fatty liver disease. The pre-existence of fat accumulation and CYP2E1 induction could be major mechanisms accounting for such hepatic susceptibility. To explore this issue, experiments were performed in obese diabetic ob/ob and db/db mice. Preliminary investigations performed in male and female wild-type, ob/ob, and db/db mice showed a selective increase in hepatic CYP2E1 activity in female db/db mice. However, liver triglycerides in these animals were significantly lower compared with ob/ob mice. Next, APAP (500 mg/kg) was administered in female wild-type, ob/ob, and db/db mice, and investigations were carried out 0.5, 2, 4, and 8 h after APAP intoxication. Liver injury 8 h after APAP intoxication was higher in db/db mice, as assessed by plasma transaminases, liver histology, and terminal deoxynucleotidyl transferase-mediated dUTP nick-end labeling assay. In db/db mice, however, the extent of hepatic glutathione depletion, levels of APAP-protein adducts, c-Jun N-terminal kinase activation, changes in gene expression, and mitochondrial DNA levels were not greater compared with the other genotypes. Furthermore, in the db/db genotype plasma lactate and β-hydroxybutyrate were not specifically altered, whereas the plasma levels of APAP-glucuronide were intermediary between wild-type and ob/ob mice. Thus, early APAP-induced hepatotoxicity was greater in db/db than ob/ob mice, despite less severe fatty liver and similar basal levels of transaminases. Hepatic CYP2E1 induction could have an important pathogenic role when APAP-induced liver injury occurs in the context of obesity and related metabolic disorders. PMID:22647274

  5. Serotonin transporter (SERT and translocator protein (TSPO expression in the obese ob/ob mouse

    Santini Ferruccio

    2011-02-01

    Full Text Available Abstract Background An ever growing body of evidences is emerging concerning metabolism hormones, neurotransmitters or stress-related biomarkers as effective modulators of eating behavior and body weight in mammals. The present study sought at examining the density and affinity of two proteins related to neurotransmission and cell metabolism, the serotonin transporter SERT and the cholesterol import-benzodiazepine site TSPO (translocator protein, in a rodent leptin-lacking mutant, the obese ob/ob mouse. Binding studies were thus carried out in brain or peripheral tissues, blood platelets (SERT and kidneys (TSPO, of ob/ob and WT mice supplied with a standard diet, using the selective radiochemical ligands [3H]-paroxetine and [3H]-PK11195. Results We observed comparable SERT number or affinity in brain and platelets of ob/ob and WT mice, whilst a significantly higher [3H]-PK11195 density was reported in the brain of ob/ob animals. TSPO binding parameters were similar in the kidneys of all tested mice. By [3H]-PK11195 autoradiography of coronal hypothalamic-hippocampal sections, an increased TSPO signal was detected in the dentate gyrus (hippocampus and choroids plexus of ob/ob mice, without appreciable changes in the cortex or hypothalamic-thalamic regions. Conclusions These findings show that TSPO expression is up-regulated in cerebral regions of ob/ob leptin-deficient mice, suggesting a role of the translocator protein in leptin-dependent CNS trophism and metabolism. Unchanged SERT in mutant mice is discussed herein in the context of previous literature as the forerunner to a deeper biochemical investigation.

  6. Autonomic dysregulation in ob/ob mice is improved by inhibition of angiotensin-converting enzyme

    Hilzendeger, A.M.; da Costa Goncalves, A.C.; Plehm, R.; Diedrich, A.; Gross, V; J.B. Pesquero; Bader, M

    2010-01-01

    The leptin-deficient ob/ob mice are insulin resistant and obese. However, the control of blood pressure in this model is not well defined. The goal of this study was to evaluate the role of leptin and of the renin-angiotensin system in the cardiovascular abnormalities observed in obesity using a model lacking leptin. To this purpose, we measured blood pressure in ob/ob and control animals by radiotelemetry combined with fast Fourier transformation before and after both leptin and enalapril tr...

  7. K-band spectroscopy of deeply embedded, young OB stars

    Bik, A.; Kaper, L.; Hanson, M.M.; Waters, L. B. F. M.

    2006-01-01

    We have obtained high resolution (R = 10,000) K-band spectra of candidate young massive stars deeply embedded in high-mass star-forming regions. These objects were selected from a near-infrared survey of 44 regions of high-mass star-formation (Kaper et al, 2006). In these clusters, 38 OB stars are identified whose K-band spectra are dominated by photospheric emission. In almost all those stars, the K-band spectra are indistinguishable from field stars. However, in some stars the profile of th...

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

    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...

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

    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.

  10. Chemical modification of B4C cap layers on Pd/B4C multilayers

    Supruangnet, Ratchadaporn; Morawe, Christian; Peffen, Jean-Christophe; Nakajima, Hideki; Rattanasuporn, Surachet; Photongkam, Pat; Jearanaikoon, Nichada; Busayaporn, Wutthikri

    2016-03-01

    Chemical modifications of B4C cap layers on sputtered Pd/B4C multilayer coatings for X-ray optical applications were investigated using X-ray reflectivity, photoemission electron spectroscopy, photoemission electron microscopy, transmission electron microscopy, energy dispersive X-ray spectroscopy, and infrared spectroscopy. The results indicate oxidation down to probing depths of about 10 nm and strong evidence for the formation of B2O3 crystals at the sample surface, while B4C like compounds are absent.

  11. Transplantation of wild-type white adipose tissue normalizes metabolic, immune and inflammatory alterations in leptin-deficient ob/ob mice

    Sennello, Joseph A.; Fayad, Raja; Pini, Maria; Gove, Melissa E.; Fantuzzi, Giamila

    2006-01-01

    Leptin-deficient ob/ob mice exhibit several metabolic and immune abnormalities, including thymus atrophy and markedly reduced inflammatory responses. We evaluated whether transplantation of wild type (WT) white adipose tissue (WAT) into ob/ob mice could mimic the effect of recombinant leptin administration in normalizing metabolic, immune and inflammatory abnormalities. Female ob/ob mice received a subcutaneous transplantation of WAT obtained from WT littermates. A separate group of ob/ob mic...

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

    Vink, Jorick S.; Drew, Janet E.; 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. T...

  13. 129I in the Ob river

    The aim of this study was: 1) to determine 129I concentrations in the Ob river, and 2) to determine 129I concentrations in surficial sediments in the river. Some results from the study are summarized in the present paper. 5 refs., 3 figs

  14. American Ginseng Berry Juice Intake Reduces Blood Glucose and Body Weight in ob/ob Mice

    Xie, J.T.; Wang, C.Z.; Ni, M.; Wu, J.A.; Mehendale, S.R.; Aung, H.H.; Foo, A.; Yuan, C.S.

    2007-01-01

    Diabetes is a serious chronic metabolic disease and has a significant impact on patients' lives and the health care system. We previously observed that the organic solvent extract of American ginseng berry possessed significant antidiabetic effects in obese diabetic ob/ob mice after intraperitoneal injection. If American ginseng berry is useful as a dietary supplement, simple preparation and oral intake would be a convenient, safe, and practical means for consumers. In this study, the simply ...

  15. The Physiology of Obese-Hyperglycemic Mice [ob/ob Mice

    Per Lindström

    2007-01-01

    This review summarizes key aspects of what has been learned about the physiology of leptin deficiency as it can be observed in obese-hyperglycemic ob/ob mice. These mice lack functional leptin. They are grossly overweight and hyperphagic, particularly at young ages, and develop severe insulin resistance. They have been used as a model for obesity and as a rich source of pancreatic islets with high insulin release capacity. The leptin deficiency manifests also with regard to immune function, t...

  16. Deflection routing scheme for GMPLS-based OBS networks

    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...

  17. Alpha-1 adrenoceptors in brown adipose tissue of lean and ob/ob mice

    Obese (ob/ob) mice have a low capacity to increase thyroxine 5'-deiodinase (T4 5'-D) in brown adipose tissue (BAT) when exposed to cold. This effect is mediated by alpha-1 (A-1) adrenoceptors. The authors objective was to find out whether BAT of the ob/ob mouse has normal A-1 receptors. Saturation analysis of binding of [3H]-WB4101 at 0.05 nM to 10 μM to crude membrane preparations (100,000 g pellets from Polytron homogenates) using the LIGAND program of Munson and Rodbard, showed two populations of binding sites in BAT of lean (+/+, 11-15 wk old) mice. Acute exposure (12 h, 140C) or acclimation to cold (3 wk, 140C) did not alter affinity or concentration of sites. Displacement with yohimbine and prazosin indicated binding of WB4101 to A-1 receptors. Very young (5 wk) lean (+/.) and obese mice had similar affinity constants (lean 0.13 +/- 0.043 and 34.2 +/- 14.9; obese, 0.12 +/- 0.028 and 20.9 +/- 5.48 nM) and concentrations (lean 22.4 +/- 3.8 and 647 +/- 137; obese, 28.6 +/- 4.6 and 547 +/- 105 fmol/mg protein) of sites. Old (1 yr) mice had high affinity sites similar to those in younger animals (KD lean 0.19 +/- 0.028, obese, 0.25 +/- 0.075; Bmax lean, 60.2 +/- 12.1; obese, 63.1 +/- 13.5 fmol/mg protein). The authors conclude that the ob/ob mouse has normal high affinity A-1 receptors in BAT. Anomalous properties of low affinity binding in old ob/ob mice could not be characterized because of high nonspecific binding. BAT of the ob/ob mouse does not lack A-1 receptors but may have a post-receptor alteration in the A-1 adrenoceptor-mediated response

  18. Alleviation of ischemia/reperfusion injury in ob/ob mice by inhibiting UCP-2 expression in fatty liver

    Chi-Dan Wan; Chun-You Wang; Tao Liu; Rui Cheng; Hong-Bo Wang

    2008-01-01

    AIM: To investigate the protective effect of target suppression of uncoupling protein-2 (UCP-2) on ischemia/ reperfusion (I/R) injury in fatty liver in ob/ob mice.METHODS: Plasmids suppressing UCP-2 expression were constructed, and transfected into fatty liver cells cultured in vitro and the ob/ob mouse I/R injury model. Serum tumor necrosis factor (TNF)-α levels, UCP-2 mRNA expression, alanine aminotransferase (ALT) levels in ob/ob mice were tested, and the pathological changes in fatty liver were observed in experimental and control groups.RESULTS: In ob/ob mouse I/R models, serum TNF-α levels were significantly higher than in normal controls. After the plasmids were transfected into the cultured cells and animal models, expression of UCP-2 mRNA was significantly reduced as compared with that in the control group (2156±015 vs 2"0-45±0-15, P < 0.05). In ob/ob mouse models, in which expression of UCP-2 was suppressed, serum ALT levels were significantly lower than those of other groups, and pathological analysis revealed that injury of liver tissues was significantly alleviated.CONCLUSION: The target suppression of UCP-2 expression in fatty liver can alleviate the I/R injury in the ob/ob mice.

  19. Adrenalectomy in genetically obese ob/ob and db/db mice increases the proton conductance pathway.

    Shargill, N S; Lupien, J R; Bray, G A

    1989-09-01

    Adrenalectomy (ADX) prevents the excessive weight gain in the genetically obese ob/ob and db/db mice. To test the possibility that this results from increased energy expenditure due to increased thermogenesis in brown adipose tissue (BAT), we measured GDP binding to mitochondria from interscapular brown adipose tissue (BAT) in db/db and ob/ob mice and their lean controls after adrenalectomy, with and without corticosterone replacement. Both the vehicle treated and corticosterone treated db/db and ob/ob mice had lower body weights than the sham-operated mice GDP binding to mitochondria from IBAT was significantly lower in both the db/db and ob/ob mice than in their lean controls. Adrenalectomy significantly increased GDP binding in all mice compared to the respective sham-operated mice, but, the percentage increase was always greater in the db/db and ob/ob mice. Corticosterone treatment of adrenalectomized db/db, ob/ob or lean mice lowered GDP binding to sham levels. Our data confirm previous findings that adrenalectomy results in increased GDP binding to mitochondria from IBAT. Injections of corticosterone into adrenalectomized mice results in a decrease in GDP binding to values which are similar to values in sham-operated mice. Thus adrenalectomy may inhibit the development of obesity by increasing the thermic activity in IBAT. PMID:2583669

  20. Solar-Type Post-T Tauri Stars in the Nearest OB Subgroups

    Mamajek, E E

    2003-01-01

    I discuss results from the recent spectroscopic survey for solar-type pre-MS stars in the Lower Centaurus-Crux (LCC) and Upper Centaurus-Lupus (UCL) OB subgroups by Mamajek, Meyer, & Liebert (2002, AJ, 124, 1670). LCC and UCL are subgroups of the Sco-Cen OB association, and the two nearest OB subgroups to the Sun. In the entire survey of 110 pre-main sequence stars, there exists only one Classical T Tauri star (PDS 66), implying that only ~1% of ~1 Msun stars are still accreting at age 13$\\pm$7 (1$\\sigma$) Myr. Accounting for observational errors, the HRD placement of the pre-MS stars is consistent with the bulk of star-formation taking place within 5-10 Myr. In this contribution, I estimate conservative upper limits to the intrinsic velocity dispersions of the post-T Tauri stars in the LCC and UCL subgroups (<1.6 km/s and <2.2 km/s, respectively; 95% CL) using Monte-Carlo simulations of Tycho-2 proper motions for candidate subgroup members. I also demonstrate that a new OB subgroup recently propose...

  1. The Origin of OB Runaway Stars

    Fujii, Michiko; Zwart, Simon Portegies

    2011-01-01

    About 20% of all massive stars in the Milky Way have unusually high velocities, the origin of which has puzzled astronomers for half a century. We argue that these velocities originate from strong gravitational interactions between single stars and binaries in the centers of star clusters. The ejecting binary forms naturally during the collapse of a young ($\\aplt 1$\\,Myr) star cluster. This model replicates the key characteristics of OB runaways in our galaxy and it explains the $\\apgt 100$\\,...

  2. Time stability of ocean bottom seismometers (OBS)

    Shariat Panahi, Shahram; Manuel Lázaro, Antonio; Corrêa Alegría, Francisco

    2010-01-01

    During the past decades, Ocean Bottom Seismometers (OBS) have played a key role in permanent seismic activity monitoring at sea as well as allowing a better understating of the earth interior. Data collected by the instrument can provide information on the ocean bottom sub-layers down to a depth of 40 km beneath the ocean floor. The accuracy of the results directly depends on the temperature stability of the crystal used as the main time base of the equipment. This paper pre...

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

    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.

  4. DUSTY OB STARS IN THE SMALL MAGELLANIC CLOUD. I. OPTICAL SPECTROSCOPY REVEALS PREDOMINANTLY MAIN-SEQUENCE OB STARS

    We present the results of optical spectroscopic follow-up of 125 candidate main sequence OB stars in the Small Magellanic Cloud (SMC) that were originally identified in the S3MC infrared imaging survey as showing an excess of emission at 24 μm indicative of warm dust, such as that associated with a transitional or debris disks. We use these long-slit spectra to investigate the origin of the 24 μm emission and the nature of these stars. A possible explanation for the observed 24 μm excess, that these are emission line stars with dusty excretion disks, is disproven for the majority of our sources. We find that 88 of these objects are normal stars without line emission, with spectral types mostly ranging from late-O to early-B; luminosity classes from the literature for a sub-set of our sample indicate that most are main-sequence stars. We further identify 17 emission-line stars, 7 possible emission-line stars, and 5 other objects with forbidden-line emission in our sample. We discover a new O6 Iaf star; it exhibits strong He II 4686 Å emission but relatively weak N III 4640 Å emission which we attribute to the lower nitrogen abundance in the SMC. Two other objects are identified with planetary nebulae, one with a young stellar object, and two with X-ray binaries. To shed additional light on the nature of the observed 24 μm excess we use optical and infrared photometry to estimate the dust properties of the objects with normal O and B star spectra and compare these properties to those of a sample of hot spots in the Galactic interstellar medium (ISM). We find that the dust properties of the dusty OB star sample resemble the properties of the Galactic sample of hot spots. Some may be runaway systems with bow-shocks resulting from a large velocity difference between star and ISM. We further investigate the nature of these dusty OB stars in a companion paper presenting mid-infrared spectroscopy and additional imaging.

  5. B4C thin films for neutron detection

    Höglund, Carina; Birch, Jens; Andersen, Ken; Bigault, Thierry; Buffet, Jean-Claude; Correa, Jonathan; Van Esch, Patrick; Guerard, Bruno; Hall-Wilton, Richard; Jensen, Jens; Khaplanov, Anton; Piscitelli, Francesco; Vettier, Christian; Vollenberg, Wilhelmus; Hultman, Lars

    2012-01-01

    Due to the very limited availability of He-3, new kinds of neutron detectors, not based on 3He, are urgently needed. Here, we present a method to produce thin films of (B4C)-B-10, with maximized detection efficiency, intended to be part of a new generation of large area neutron detectors. B4C thin Films have been deposited onto Al-blade and Si wafer substrates by dc magnetron sputtering from (B4C)-B-nat and (B4C)-B-10 targets in an Ar discharge, using an industrial deposition system. The film...

  6. Data acquisition system for a cabled ocean bottom seismometer (OBS)

    Rogalski, Tomasz; Shariat Panahi, Shahram; Río Fernandez, Joaquín del; Manuel Lázaro, Antonio

    2010-01-01

    Ocean Bottom Seismometers (OBS) are highly used to monitor seismic activities at sea. They are also used to detect tsunamis and generate warning alarms. This paper presents a data acquisition system built for an OBS with capability to synchronize time through IEEE-1588 protocol. This acquisition system provides real time data through the Ethernet making it suitable for OBSs deployed at seafloor observatories.

  7. The origin of OB runaway stars.

    Fujii, Michiko S; Portegies Zwart, Simon

    2011-12-01

    About 20% of all massive stars in the Milky Way have unusually high velocities, the origin of which has puzzled astronomers for half a century. We argue that these velocities originate from strong gravitational interactions between single stars and binaries in the centers of star clusters. The ejecting binary forms naturally during the collapse of a young (≤1 million years old) star cluster. This model replicates the key characteristics of OB runaways in our galaxy, and it explains the presence of runaway stars of ≥100 solar masses (M(⊙)) around young star clusters, such as R136 and Westerlund 2. The high proportion and the distributions in mass and velocity of runaways in the Milky Way are reproduced if the majority of massive stars are born in dense and relatively low-mass (5000 to 10,000 M(⊙)) clusters. PMID:22096104

  8. SUPER STAR CLUSTERS VERSUS OB ASSOCIATIONS

    Super star clusters (Mecl > 105 Msun) are the largest stellar nurseries in our local Universe, containing hundreds of thousands to millions of young stars within a few light years. Many of these systems are found in external galaxies, especially in pairs of interacting galaxies, and in some dwarf galaxies, but relatively few in disk galaxies like our own Milky Way. We show that a possible explanation for this difference is the presence of shear in normal spiral galaxies which impedes the formation of the very large and dense super star clusters but prefers the formation of loose OB associations possibly with a less massive cluster at the center. In contrast, in interacting galaxies and in dwarf galaxies, regions can collapse without having a large-scale sense of rotation. This lack of rotational support allows the giant clouds of gas and stars to concentrate into a single, dense, and gravitationally bound system.

  9. Open clusters in Auriga OB2

    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.

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

    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.

  11. Nonlinear waveform analysis for water-layer response and its application to high-frequency receiver function analysis using OBS array

    Akuhara, Takeshi; Mochizuki, Kimihiro; Kawakatsu, Hitoshi; Takeuchi, Nozomu

    2016-07-01

    Determination of a response of the seawater column to teleseismic plane wave is important to suppress adverse effects of water reverberations in calculating receiver functions (RFs) using ocean-bottom seismometer (OBS) records. We present a novel nonlinear-waveform analysis method using the simulated annealing algorithm to determine such a water-layer response recorded by an OBS array. We then demonstrate its usefulness for the RF estimation through its application to synthetic and observed data. Synthetic experiments suggest that the water-layer response constrained in this way has a potential to improve RFs of OBS records drastically even in the high-frequency range (to 4 Hz). By applying it to data observed by the OBS array around the Kii Peninsula, southwestern Japan, we identified a low-velocity zone at the top of the subducting Philippine Sea plate. This zone may represent the incoming fluid-rich sediment layer that has been reported by active source seismic survey.

  12. Retention of deuterium implanted into B4C-overlaid isotropic graphites and hot-pressed B4C

    Retention characteristics of two kinds of B4C-overlaid graphites and hot-pressed B4C were investigated. An ion beam of 3 keV D2+ was implanted into the specimens at room temperature. The amount of retained deuteriums was measured as function of the implantation fluence and temperature by elastic recoil detection analysis. Thermal release behavior of implanted deuteriums was also measured by isochronal annealing. The concentration of retained deuterium reaches saturation similarly in three kinds of B4C-overlaid specimens at the fluences over 1018 D+/cm2 as in isotropic graphite. The release temperature, at which the number of retained deuterium decreases to one half in isochronal annealing are about 250 K lower for three kinds of B4C specimens than for graphite. The release temperature of deuterium from unsaturated hot-pressed B4C isochronal annealing is about 500 K higher than that from saturated one. (orig.)

  13. The radial distribution of OB star formation in the Galaxy

    Bronfman, L; May, J; Nyman, L A A

    2000-01-01

    We present the azimuthally averaged radial distribution of 748 regions of OB star formation in the whole galactic disk, based on our previous CS(2-1) survey of UC H II regions. Embedded massive stars produce a total FIR luminosity of 1.39E8 Lsun within the range 0.2

  14. A M2FS Spectroscopic Study of Low-mass Young Stars in Orion OB1

    Kaleida, Catherine C.; Briceno, Cesar; Calvet, Nuria; Mateo, Mario L.; Hernandez, Jesus

    2015-01-01

    Surveys of pre-main sequence stars in the ~4-10 Myr range provide a window into the decline of the accretion phase of stars and the formation of planets. Nearby star clusters and stellar associations allow for the study of these young stellar populations all the way down to the lowest mass members. One of the best examples of nearby 4-10 Myr old stellar populations is the Orion OB1 association. The CIDA Variability Survey of Orion OB1 (CVSO - Briceño et al. 2001) has used the variability properties of low-mass pre-main-sequence (PMS) stars to identify hundreds of K and M-type stellar members of the Orion OB1 association, a number of them displaying IR-excess emission and thought to be representative of more evolved disk-bearing young stars. Characterizing these young, low-mass objects using spectroscopy is integral to understanding the accretion phase in young stars. We present preliminary results of a spectroscopic survey of candidate and confirmed Orion OB1 low-mass members taken during November 2014 and February 2014 using the Michigan/Magellan Fiber Spectrograph (M2FS), a PI instrument on the Magellan Clay Telescope (PI: M. Matteo). Target fields located in the off-cloud regions of Orion were identified in the CVSO, and observed using the low and high-resolution modes of M2FS. Both low and high-resolution spectra are needed in order to confirm membership and derive masses, ages, kinematics and accretion properties. Initial analysis of these spectra reveal many new K and M-type members of the Orion OB1 association in these low extinction, off-cloud areas. These are the more evolved siblings of the youngest stars still embedded in the molecular clouds, like those in the Orion Nebula Cluster. With membership and spectroscopic indicators of accretion we are building the most comprehensive stellar census of this association, enabling us to derive a robust estimate of the fraction of young stars still accreting at a various ages, a key constraint for the end of

  15. Isomerisation of c4-c6 aldoses with zeolites

    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 elevat...... the catalyst. The ketoses obtained are used as sweeteners in the food and/or brewery industry, or treated to obtain downstream platform chemicals such as lactic acid, HMF, levulinic acid, furfural, MMHB, and the like....

  16. Reverse time migration of multiples for OBS data

    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.

  17. Performance of a distributed WR-OBS control architecture

    Zhou Lan; Hongxiang Guo; Jian Wu; Jintong Lin

    2005-01-01

    This paper proposes a new distributed wavelength-routed optical burst switching (WR-OBS) network architecture and two corresponding control protocols. By taking advantage of merits from both just enough time (JET) protocol and two-way signaling method, this new control architecture outperforms traditional JET OBS network in points of burst loss probability, system throughput and centralized WROBS network in network scalability confirmed by computer simulations. Further simulation is developed to compare the performance of the two control protocols, which leads to instructive discussion in real WR-OBS network design.

  18. ESTIMATION OF THE BURST LENGTH IN OBS NETWORKS

    Pallavi S.; M. Lakshmi

    2014-01-01

    This paper presents an overview of the optical burst switching (OBS) and discusses the major components. In OBS, the length of the burst arriving at a particular node is unknown, and hence, node design is very complex. In OBS first control, packet is transmitted and reserve the path as in circuit switching, thereafter, the data bursts is transmitted. In this paper, a poisson arrival of packets is considered and estimation is made on the size of the burst length. The results presented in the p...

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

    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

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

    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.

  1. Spatial Distribution and Kinematics of OB Stars

    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, $...

  2. Open clusters in AurOB2

    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...

  3. Analysis of methane biodegradation by Methylosinus trichosporium OB3b

    Rodrigues, Andréa dos Santos; Salgado, Belkis Valdman e Andréa Medeiros

    2009-01-01

    The microbial oxidation of methane in the atmosphere is performed by methanotrophic bacteria that use methane as a unique source of carbon and energy. The objective of this work consisted of the investigation of the best conditions of methane biodegradation by methanotrophic bacteria Methylosinus trichosporium OB3b that oxidize it to carbon dioxide, and the use of these microorganisms in monitoring methods for methane. The results showed that M. trichosporium OB3b was capable to degrade metha...

  4. Il nuovo OBS/H dell’INGV

    D'Anna, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Mangano, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; D'Alessandro, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; D'Anna, R.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Passafiume, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Speciale, S.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Amato, A.

    2009-01-01

    In 2005, thanks to the 3-year agreement between Dipartimento Nazionale della Protezione Civile (DPC) and Istituto Nazionale di Geofisica e Vulcanologia (INGV) - Centro Nazionale Terremoti (CNT), the project of the first Italian “Ocean Bottom Seismometer with Hydrophone” (OBS/H) for long-term deployment was developed at the OBS Lab of the Gibilmanna Observatory (Sicily). The drawing of the instrument started in January 2005 and, after 18 months, the prototype was ready for test in ...

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

    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. PMID:25830704

  6. Cygnus OB2 DANCe: A high precision proper motion study of the Cygnus OB2 association

    Wright, Nicholas J; Drew, Janet E; Sarro, Luis Manuel; Bertin, Emmanuel; Cuillandre, Jean-Charles; Barrado, David

    2016-01-01

    We present a high-precision proper motion study of 873 X-ray and spectroscopically selected stars in the massive OB association Cygnus OB2 as part of the DANCe project. These were calculated from images spanning a 15 year baseline and have typical precisions < 1 mas/yr. We calculate the velocity dispersion in the two axes to be $\\sigma_\\alpha(c) = 13.0^{+0.8}_{-0.7}$ and $\\sigma_\\delta(c) = 9.1^{+0.5}_{-0.5}$ km/s, using a 2-component, 2-dimensional model that takes into account the uncertainties on the measurements. This gives a 3-dimensional velocity dispersion of $\\sigma_{3D} = 17.8 \\pm 0.6$ km/s implying a virial mass significantly larger than the observed stellar mass, confirming that the association is gravitationally unbound. The association appears to be dynamically unevolved, as evidenced by considerable kinematic substructure, non-isotropic velocity dispersions and a lack of energy equipartition. The proper motions show no evidence for a global expansion pattern, with approximately the same amoun...

  7. Deferoxamine ameliorates hepatosteatosis via several mechanisms in ob/ob mice.

    Xue, Han; Chen, Di; Zhong, Yan-Ke; Zhou, Zhen-Diao; Fang, Shi-Xin; Li, Ming-Yao; Guo, Chuang

    2016-07-01

    Hepatic iron accumulation may be responsible for the pathology of nonalcoholic fatty liver disease (NAFLD), which is both increasingly prevalent in conjunction with obesity and associated with comorbidities. The efficacy of iron reduction therapies, such as phlebotomy or dietary iron restriction, has been demonstrated in patient and animal models, including models of diabetes and obesity; however, the effects on and exact mechanisms responsible for iron depletion in NAFLD have not been clearly elucidated. Our study investigated the role of iron depletion by deferoxamine (DFO) treatment of ob/ob mice with hepatic steatosis. We found that DFO reduced hepatic iron deposition and regulated intracellular iron concentration in a homeostatic process following 15 days of treatment. Compared with vehicle treatment, DFO significantly improved hepatic steatosis by upregulating proteins related to lipid metabolism. Meanwhile, the reduction of free radical formation and proinflammatory cytokines, as well as the increase of hypoxia-inducible factor-1α pathway proteins and Bcl2/Bax ratio, further indicated that DFO was effective for liver protection and hepatic adaptation. These findings show that the intraperitoneal delivery of DFO provides a potential means of both preventing the progression of NAFLD and accelerating healing of hepatic steatosis, with the potential for rapid clinical application. PMID:27447538

  8. Nuclear triiodothyronine receptor binding characteristics and occupancy in obese (ob/ob) mice

    Hillgartner, F.B.; Romsos, D.R.

    1987-03-01

    Obese (ob/ob) mice exhibit reduced adaptive thermogenesis associated with an impairment of thyroid hormone action. The mechanism underlying the latter defect was investigated by comparing the binding characteristics and occupancy of solubilized nuclear 3,5,3'-triiodothyronine (T/sub 3/) receptors from livers of lean and obese mice. T/sub 3/ concentration was measured by radioimmunoassay. Scatchard analysis showed minimal differences in B/sub max/ and K/sub d/ between phenotypes at both 4 and 8-10 wk of age, indicating that reduced hepatic thyroid hormone expression in obese mice is not caused by alterations in nuclear receptor concentration or affinity. In contrast, nuclear T/sub 3/ receptor occupancy (endogenous T/sub 3/ associated with the specific receptor divided by B/sub max/) was 14 and 23% lower in 4- and 8- to 10-wk old obese mice, respectively. Together with reported changes in hepatic thyroid hormone-sensitive enzymes, these data are consistent with a diminished nuclear T/sub 3/ signal initiating thyroid hormone action in obese mice. Decreased nuclear T/sub 3/ receptor occupancy may be secondary to a low transport of plasma T/sub 3/ to the nuclear pool. In conclusion, impaired hepatic thyroid hormone action in obese mice is mediated in part at least by a reduction in nuclear T/sub 3/ receptor occupancy.

  9. Nuclear triiodothyronine receptor binding characteristics and occupancy in obese (ob/ob) mice

    Obese (ob/ob) mice exhibit reduced adaptive thermogenesis associated with an impairment of thyroid hormone action. The mechanism underlying the latter defect was investigated by comparing the binding characteristics and occupancy of solubilized nuclear 3,5,3'-triiodothyronine (T3) receptors from livers of lean and obese mice. T3 concentration was measured by radioimmunoassay. Scatchard analysis showed minimal differences in B/sub max/ and K/sub d/ between phenotypes at both 4 and 8-10 wk of age, indicating that reduced hepatic thyroid hormone expression in obese mice is not caused by alterations in nuclear receptor concentration or affinity. In contrast, nuclear T3 receptor occupancy (endogenous T3 associated with the specific receptor divided by B/sub max/) was 14 and 23% lower in 4- and 8- to 10-wk old obese mice, respectively. Together with reported changes in hepatic thyroid hormone-sensitive enzymes, these data are consistent with a diminished nuclear T3 signal initiating thyroid hormone action in obese mice. Decreased nuclear T3 receptor occupancy may be secondary to a low transport of plasma T3 to the nuclear pool. In conclusion, impaired hepatic thyroid hormone action in obese mice is mediated in part at least by a reduction in nuclear T3 receptor occupancy

  10. Impaired transport of thyroid hormones into livers of obese (ob/ob) mice

    Obese (ob/ob) mice exhibit impaired hepatic thyroid hormone action that is mediated, at least in part, by a reduced nuclear 3,5,3'-triiodothyronine (T3) receptor occupancy. The possibility that lowered occupancy in obese mice may be caused by decreased transport of T3 across the hepatic plasma membrane was examined by measuring the unidirectional influx of [125I]T3 into livers of 8- to 10-wk-old obese and lean mice using a tissue-sampling portal vein-injection technique. Influx of [125I]thyroxine (T4), a substrate for T4 5'-deiodinase, was also measured. Unidirectional clearance of T3 and T4 was 64 and 80% lower, respectively, in obese mice than in lean mice. Hepatic T3 and T4 uptake was nonsaturable in both lean and obese mice, suggesting that transport occurs by lipid-mediated free diffusion. Clearance of another lipid-soluble hormone, hydrocortisone, was also lower in obese mice than in lean mice. Decreased membrane permeability to the above hormones in obese mice may result from reported changes in membrane lipid composition. In conclusion, decreased hepatic thyroid hormone uptake may contribute to impaired thyroid hormone action and T3 production in livers of obese mice

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

    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.

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

    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.

  13. Gender-specific metabolomic profiling of obesity in leptin-deficient ob/ob mice by 1H NMR spectroscopy.

    Eun-Young Won

    Full Text Available Despite the numerous metabolic studies on obesity, gender bias in obesity has rarely been investigated. Here, we report the metabolomic analysis of obesity by using leptin-deficient ob/ob mice based on the gender. Metabolomic analyses of urine and serum from ob/ob mice compared with those from C57BL/6J lean mice, based on the (1H NMR spectroscopy in combination with multivariate statistical analysis, revealed clear metabolic differences between obese and lean mice. We also identified 48 urine and 22 serum metabolites that were statistically significantly altered in obese mice compared to lean controls. These metabolites are involved in amino acid metabolism (leucine, alanine, ariginine, lysine, and methionine, tricarbocylic acid cycle and glucose metabolism (pyruvate, citrate, glycolate, acetoacetate, and acetone, lipid metabolism (cholesterol and carnitine, creatine metabolism (creatine and creatinine, and gut-microbiome-derived metabolism (choline, TMAO, hippurate, p-cresol, isobutyrate, 2-hydroxyisobutyrate, methylamine, and trigonelline. Notably, our metabolomic studies showed distinct gender variations. The obese male mice metabolism was specifically associated with insulin signaling, whereas the obese female mice metabolism was associated with lipid metabolism. Taken together, our study identifies the biomarker signature for obesity in ob/ob mice and provides biochemical insights into the metabolic alteration in obesity based on gender.

  14. Hot pressing of B4C/SiC composites

    B4C/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 B4C/SiC composite samples were lower than monolithic B4C in all experimental conditions. (authors)

  15. B4C thin films for neutron detection

    Due to the very limited availability of 3He, new kinds of neutron detectors, not based on 3He, are urgently needed. Here, we present a method to produce thin films of 10B4C, with maximized detection efficiency, intended to be part of a new generation of large area neutron detectors. B4C thin films have been deposited onto Al-blade and Si wafer substrates by dc magnetron sputtering from natB4C and 10B4C targets in an Ar discharge, using an industrial deposition system. The films were characterized with scanning electron microscopy, elastic recoil detection analysis, x-ray reflectivity, and neutron radiography. We show that the film-substrate adhesion and film purity are improved by increased substrate temperature and deposition rate. A deposition rate of 3.8 A/s and substrate temperature of 400 deg. C result in films with a density close to bulk values and good adhesion to film thickness above 3 μm. Boron-10 contents of almost 80 at. % are obtained in 6.3 m2 of 1 μm thick 10B4C thin films coated on Al-blades. Initial neutron absorption measurements agree with Monte Carlo simulations and show that the layer thickness, number of layers, neutron wavelength, and amount of impurities are determining factors. The study also shows the importance of having uniform layer thicknesses over large areas, which for a full-scale detector could be in total ∼1000 m2 of two-side coated Al-blades with ∼1 μm thick 10B4C films.

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

    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

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

    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 × 10(7) 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. OB protein binds specifically to the choroid plexus of mice and rats.

    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. PMID:8643634

  19. Directional crystallization of B4C-NbB2 and B4C-MoB2 eutectic compositions

    We studied the directional crystallization of different compositions in B4C-NbB2 and B4C-MoB2 systems. The eutectic compositions for both systems are evaluated. It is shown that in the first system the rod-like eutectic structure is formed, in second, the 'Chinese hieroglyphics'. In both cases high hardness and high microplasticity are observed, which are much more than for individual component phases. These compositions may be considered as a new kind of self-strengthening composite materials

  20. Herbig Ae/Be Stars in nearby OB associations

    Hernández, J; Hartmann, L; Briceño, C; Sicilia-Aguilar, A; Berlind, P; Hernandez, Jesus; Calvet, Nuria; Hartmann, Lee; Briceno, Cesar; Sicilia-Aguilar, Aurora; Berlind, Perry

    2004-01-01

    We have carried out a study of the early type stars in nearby OB associations spanning an age range of $\\sim$ 3 to 16 Myr, with the aim of determining the fraction of stars which belong to the Herbig Ae/Be class. We studied the B, A, and F stars in the nearby ($\\le 500$ pc) OB associations Upper Scorpius, Perseus OB2, Lacerta OB1, and Orion OB1, with membership determined from Hipparcos data. We obtained spectra for 440 Hipparcos stars in these associations, from which we determined accurate spectral types, visual extinctions, effective temperatures, luminosities and masses, using Hipparcos photometry. Using colors corrected for reddening, we find that the Herbig Ae/Be stars and the Classical Be stars (CBe) occupy clearly different regions in the JHK diagram. Thus, we use the location on the JHK diagram, as well as the presence of emission lines and of strong 12 microns flux relative to the visual to identify the Herbig Ae/Be stars in the associations. We find that the Herbig Ae/Be stars constitute a small fr...

  1. Obs4MIPS: Satellite Observations for Model Evaluation

    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. JAVOBS: A Flexible Simulator for OBS Network Architectures

    Oscar Pedrola

    2010-02-01

    Full Text Available Since the OBS paradigm has become a potential candidate to cope with the needs of the future all optical networks, it has really caught the attention from both academia and industry worldwide. In this direction, OBS networks have been investigated under many different scenarios comprising numerous architectures and strategies. This heterogeneous context encouraged the development of various simulation tools. In this paper we present our novel Java-based OBS network simulator called JAVOBS. We discuss its architecture, study its performance and provide some exemplary results that point out its remarkable flexibility. This flexibility should permit an easy integration of upcoming new network protocol designs but also support changing and evolving research goals.

  3. ESTIMATION OF THE BURST LENGTH IN OBS NETWORKS

    Pallavi S.

    2014-05-01

    Full Text Available This paper presents an overview of the optical burst switching (OBS and discusses the major components. In OBS, the length of the burst arriving at a particular node is unknown, and hence, node design is very complex. In OBS first control, packet is transmitted and reserve the path as in circuit switching, thereafter, the data bursts is transmitted. In this paper, a poisson arrival of packets is considered and estimation is made on the size of the burst length. The results presented in the paper clearly reveal that, the very large burst length is un-common. Therefore, most of the times, very short or average length burst is expected. Therefore it is concluded in this paper, buffering of burst at the contending nodes is a good option which increases the throughput and reduces the average delay. Finally, the buffering in conjunction with deflection of bursts will provide very effective solution.

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

    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...

  5. Marine TAIGER OBS Experiment and its future prospects

    Lee, C.; Wang, T.; van Avendonk, H. J.; Huang, Y.; Lin, J.; Lallemand, S.; Klingelhoeher, F.

    2009-12-01

    A total of 260 OBSs were deployed in the marine TAIGER program from late March to late July, 2009. These data were collected by US Columbia University’s R/V Langseth as the big-power seismic shooting ship and 10 Taiwanese ships to take terms for supporting of the OBS experiment in the entire seismic cruises. The OBS were provided by the National Taiwan Ocean University, French IFREMER and Scripps Institution of Oceanography. During these 4 months, we have worked around Taiwan in the South China Sea, Luzon Arc, East Taiwan and West Philippine Basin. All efforts are put together by many earth scientists from Taiwan, USA and France under one major purpose, to get a better understanding of the Taiwan mountain building processes. As a result, these new data will provide as a base to combine with many other disciplinal studies, such as the multi-channel seismic, land recorded seismometer data, gravity and magnetic as well as the natural earthquake data recorded by the OBS during the experiment time. Four very preliminary OBS data analyses will be presented in the same T25 postal section. Beside the research, we also carried out our teaching to our students on board a Taiwanese student training ship, Yu-Yin No.2. Therefore, an educational post is also to be shown in the ED01 section. Even the data analyses are in an early stage, but we are exciting about it. For example, 3 OBS profiles (T4, T5 and T6) in the East Taiwan were shot twice in normal and reversed directions with different shot intervals (30 and 60 seconds per shot). This exercise will be important to interpret the complicate collision/subduction structures in the East Taiwan. Two OBS profiles (T1 and T2) in the Luzon Arc were shot 5 times in the separated R/V Langseth cruises (due to the typhoon effects), again with different shot intervals (20 and 60 seconds per shot). These will provide us more opportunities to examine the collisional features in between Taiwan and Luzon. One OBS long profile (550 km) was

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

    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.

  7. Octonionic Representations of GL(8,R) and GL(4,C)

    Stefano De LeoDip. di Fisica, INFN, Lecce; Khaled Abdel-Khalek(Dip. di Fisica, INFN, Lecce)

    2015-01-01

    Octonionic algebra being nonassociative is difficult to manipulate. We introduce left-right octonionic barred operators which enable us to reproduce the associative GL(8,R) group. Extracting the basis of GL(4,C), we establish an interesting connection between the structure of left-right octonionic barred operators and generic 4x4 complex matrices. As an application we give an octonionic representation of the 4-dimensional Clifford algebra.

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

    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.

  9. Anti-obesity activity of diglyceride containing conjugated linoleic acid in C57BL/6J ob/ob mice

    Hue, Jin-Joo; Lee, Ki Nam; Jeong, Jae-Hwang; Lee, Sang-Hwa; Lee, Young Ho; Jeong, Seong-woon; Nam, Sang Yoon; Yun, Young Won; Lee, Beom Jun

    2009-01-01

    This study was to investigate the anti-obesity effects of diglyceride (DG)-conjugated linoleic acid (CLA) containing 22% CLA as fatty acids in C57BL/6J ob/ob male mice. There were four experimental groups including vehicle control, DG, CLA, and DG-CLA. The test solutions of 750 mg/kg dose were orally administered to the mice everyday for 5 weeks. CLA treatments significantly decreased mean body weight in the obese mice throughout the experimental period compared to the control (p < 0.01). All...

  10. Sitagliptin can inhibit the development of hepatic steatosis in high-fructose diet-fed ob/ob mice

    Sujishi, Tetsuya; Fukunishi, Shinya; Ii, Masaaki; Nakamura, Ken; Yokohama, Keisuke; Ohama, Hideko; Tsuchimoto, Yusuke; Asai, Akira; Tsuda, Yasuhiro; Higuchi, Kazuhide

    2015-01-01

    The beneficial effect of dipeptidyl peptidase-4 inhibition on diet-induced extra-pancreatic effects, especially on liver tissue remains poorly understood. Thus, we made the experimental designs as follows; five-week-old male ob/ob mice, which develop type 2 diabetic mellitus and nonalcoholic fatty liver disease by taking a high-carbohydrate diet (HCD), were divided into a group in which a HCD was given for 8 weeks as control, and another in which a HCD added with 0.0018% sitagliptin was given...

  11. OB Associations at the Upper End of the Milky Way Luminosity Function

    Rahman, Mubdi; Matzner, Christopher D.; Moon, Dae-Sik

    2013-04-01

    The Milky Way's most luminous, young, and massive (M gsim 104 M ⊙) star clusters and OB associations have largely evaded detection despite knowledge of their surrounding H II regions. We search for these clusters and associations within the 40 star-forming complexes from Rahman & Murray in the 13 most luminous Wilkinson Microwave Anisotropy Probe (WMAP) free-free emission sources of the Galaxy. Selecting for objects with the dust-reddened colors of OB stars, we identify new candidate associations using the Two Micron All Sky Survey point-source catalog. In 40 star-forming complexes searched, 22 contain cluster/association candidates with sizes and masses in the range of 3'-26' and 102.3-105 M ⊙. Of the 22 candidates, at least seven have estimated masses >~ 104 M ⊙, doubling the number of such massive clusters known in the Galaxy. Only one of the searched WMAP sources remains without a candidate. Applying our method to a statistically similar set of test locations, we estimate that 3.0 ± 0.6 of our 22 candidate associations are unrelated to the star-forming complexes. In addition, the apparent extinctions of our candidate associations correlate well with the predictions from a Galactic model. These facts, along with the clear detection of a known OB association and the previous spectral verification of one cluster found by this method, validate our method. In eight of the most luminous WMAP sources, the candidate associations can account for the observed free-free flux. With our new compilation, the Galactic census of young, massive stellar associations may now be about half complete.

  12. OB ASSOCIATIONS AT THE UPPER END OF THE MILKY WAY LUMINOSITY FUNCTION

    Rahman, Mubdi; Matzner, Christopher D.; Moon, Dae-Sik, E-mail: mubdi@pha.jhu.edu [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H8 (Canada)

    2013-04-01

    The Milky Way's most luminous, young, and massive (M {approx}> 10{sup 4} M{sub Sun }) star clusters and OB associations have largely evaded detection despite knowledge of their surrounding H II regions. We search for these clusters and associations within the 40 star-forming complexes from Rahman and Murray in the 13 most luminous Wilkinson Microwave Anisotropy Probe (WMAP) free-free emission sources of the Galaxy. Selecting for objects with the dust-reddened colors of OB stars, we identify new candidate associations using the Two Micron All Sky Survey point-source catalog. In 40 star-forming complexes searched, 22 contain cluster/association candidates with sizes and masses in the range of 3'-26' and 10{sup 2.3}-10{sup 5} M{sub Sun }. Of the 22 candidates, at least seven have estimated masses {approx}> 10{sup 4} M{sub Sun }, doubling the number of such massive clusters known in the Galaxy. Only one of the searched WMAP sources remains without a candidate. Applying our method to a statistically similar set of test locations, we estimate that 3.0 {+-} 0.6 of our 22 candidate associations are unrelated to the star-forming complexes. In addition, the apparent extinctions of our candidate associations correlate well with the predictions from a Galactic model. These facts, along with the clear detection of a known OB association and the previous spectral verification of one cluster found by this method, validate our method. In eight of the most luminous WMAP sources, the candidate associations can account for the observed free-free flux. With our new compilation, the Galactic census of young, massive stellar associations may now be about half complete.

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

    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

  14. ADC Module built for an ocean bottom seismometer (OBS)

    Carreras, Normandino; Shariat Panahi, Shahram; Manuel Lázaro, Antonio

    2010-01-01

    This paper presents the new data acquisition system designed for autonomous Ocean Bottom Seismometers (OBS) to study the earth dynamics and internal structure. This part is the responsible to acquire the signals from two different sensors to be processed. The analog-to-digital converter module is based on input amplifiers, modulator and digital filter.

  15. ObsPy: A Python Toolbox for Seismology

    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.

  16. The massive star population of Cygnus OB2

    Wright, Nicholas J.; Drew, Janet E.; Mohr-Smith, Michael

    2015-05-01

    We have compiled a significantly updated and comprehensive census of massive stars in the nearby Cygnus OB2 association by gathering and homogenizing data from across the literature. The census contains 169 primary OB stars, including 52 O-type stars and 3 Wolf-Rayet stars. Spectral types and photometry are used to place the stars in a Hertzsprung-Russell diagram, which is compared to both non-rotating and rotating stellar evolution models, from which stellar masses and ages are calculated. The star formation history and mass function of the association are assessed, and both are found to be heavily influenced by the evolution of the most massive stars to their end states. We find that the mass function of the most massive stars is consistent with a `universal' power-law slope of Γ = 1.3. The age distribution inferred from stellar evolutionary models with rotation and the mass function suggest the majority of star formation occurred more or less continuously between 1 and 7 Myr ago, in agreement with studies of low- and intermediate-mass stars in the association. We identify a nearby young pulsar and runaway O-type star that may have originated in Cyg OB2 and suggest that the association has already seen its first supernova. Finally we use the census and mass function to calculate the total mass of the association of 16 500^{+3800}_{-2800} M⊙, at the low end, but consistent with, previous estimates of the total mass of Cyg OB2. Despite this Cyg OB2 is still one of the most massive groups of young stars known in our Galaxy making it a prime target for studies of star formation on the largest scales.

  17. Separation of B4C powder by air classification

    Large quantities of bulk powder can be separated according to particle size and density by air classifiers. Classifiers disperse the powder and usually achieve size differentiation by drag and centrifugal forces acting on individual particles in the gas stream. A Donaldson ''acucut'' Classifier for the separation of B4C powder is evaluated. Experimental tests were conducted to determine the particle cut sizes and powder yields obtained by variation of operating parameters. To assess the classifier's performance further results of the sharpness of the powder cuts were evaluated and compared with the vendor's prediction. 7 figures, 3 tables

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

    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 duty cycle. Similar increases in V̇E and its components were observed in non-flow-limited breaths during NREM and REM sleep. These responses suggest that leptin stabilized pharyngeal patency and increased drive to both the upper airway and diaphragm during sleep. PMID:26472867

  19. The stellar association around Gamma Velorum and its relationship with Vela OB2

    Jeffries, R D; Walter, F M; Pozzo, M P; Devey, C R

    2008-01-01

    We present the results of a photometric BVI survey of 0.9 square degrees around the Wolf-Rayet binary gamma^2 Vel and its early-type companion gamma^1 Vel. Several hundred PMS stars are identified and the youth of a subset of these is confirmed by the presence of lithium, H-alpha emission and X-ray activity. We show that the PMS stars are kinematically coherent and spatially concentrated around gamma Vel. The PMS stars have similar proper motions to gamma Vel, to main-sequence stars around gammaVel and to early-type stars of the wider Vela OB2 association of which gamma^2 Vel is the brightest member. The ratio of main-sequence stars to low-mass (0.1-0.6 Msun) PMS stars is consistent with a Kroupa mass function. Main-sequence fitting to stars around gamma Vel gives a distance modulus of 7.76+/-0.07 mag, consistent with a similarly-determined distance for Vela OB2 and with interferometric distances to gamma^2 Vel. High-mass stellar models indicate an age of 3-4 Myr for gamma^2 Vel, but the low-mass PMS stars ha...

  20. Cool neutral hydrogen in the direction of an anonymous OB association

    H I self-absorption is seen in the direction l = 55.06 probably physically associated with an anonymous OB association which has the Cepheid GY Sagittae as a member. The cool H I is in two clouds at least 15 pc in diameter located 3.25 kpc from the Sun. If their temperature is approx. =50 K, the cloud masses are approx. =103 M/sub sun/. The neutral atomic hydrogen clouds are probably warm envelopes surrounding cold molecular cloud cores because CO observations in this region show two molecular clouds nearly coincident with the absorbing H i gas. Since the OB association is only approx. =107 years old, these clouds are likely to be part of the original cloud complex from which the stellar cluster formed. The H i clouds are part of the larger Arecibo survey of self-absorption which suggests that many of the Arecibo clouds are associated with heretofore unidentified star clusters. Even if this is generally not the case, the Arecibo objects have accurate kinematic distances and thus provide a new sample of cool H I clouds whose thermodynamic properties can be studied

  1. Effects of caloric restriction on O-GlcNAcylation, Ca(2+) signaling, and learning impairment in the hippocampus of ob/ob mice.

    Jeon, Byeong Tak; Heo, Rok Won; Jeong, Eun Ae; Yi, Chin-Ok; Lee, Jong Youl; Kim, Kyung Eun; Kim, Hwajin; Roh, Gu Seob

    2016-08-01

    Diabetes may adversely affect cognitive function and, conversely, caloric restriction (CR) increases longevity and improves memory. To shed light on the unknown underlying mechanisms involved in these observations, we examined the effects of CR on serum metabolic parameters and hippocampal protein expression in the ob/ob mice model of obesity-induced diabetes. We found that CR reduced hepatic steatosis and insulin resistance in ob/ob mice. In addition, CR increased the levels of hippocampal O-linked-N-acetylglucosamine (O-GlcNAc) and GlcNAc transferase and decreased the expression of calcium/calmodulin-dependent protein kinase II, lipocalin-2, and phosphorylated tau. Furthermore, CR lessened the learning deficits that are typically seen in ob/ob mice. These findings indicate that CR may reverse obesity-related brain glucose impairment and intracellular Ca(2+) dysfunction and relieve learning impairment associated with diabetes. PMID:27318140

  2. Loss of FXR protects against diet-induced obesity and accelerates liver carcinogenesis in ob/ob mice.

    Zhang, Yanqiao; Ge, Xuemei; Heemstra, Lydia A; Chen, Wei-Dong; Xu, Jiesi; Smith, Joseph L; Ma, Huiyan; Kasim, Neda; Edwards, Peter A; Novak, Colleen M

    2012-02-01

    Farnesoid X receptor (FXR) is known to play important regulatory roles in bile acid, lipid, and carbohydrate metabolism. Aged (>12 months old) Fxr(-/-) mice also develop spontaneous liver carcinomas. In this report, we used three mouse models to investigate the role of FXR deficiency in obesity. As compared with low-density lipoprotein receptor (Ldlr) knockout (Ldlr(-/-)) mice, the Ldlr(-/-)Fxr(-/-) double-knockout mice were highly resistant to diet-induced obesity, which was associated with increased expression of genes involved in energy metabolism in the skeletal muscle and brown adipose tissue. Such a striking effect of FXR deficiency on obesity on an Ldlr(-/-) background led us to investigate whether FXR deficiency alone is sufficient to affect obesity. As compared with wild-type mice, Fxr(-/-) mice showed resistance to diet-induced weight gain. Interestingly, only female Fxr(-/-) mice showed significant resistance to diet-induced obesity, which was accompanied by increased energy expenditure in these mice. Finally, we determined the effect of FXR deficiency on obesity in a genetically obese and diabetic mouse model. We generated ob(-/-)Fxr(-/-) mice that were deficient in both Leptin and Fxr. On a chow diet, ob(-/-)Fxr(-/-) mice gained less body weight and had reduced body fat mass as compared with ob/ob mice. In addition, we observed liver carcinomas in 43% of young (<11 months old) Ob(-/-)Fxr(-/-) mice. Together these data indicate that loss of FXR prevents diet-induced or genetic obesity and accelerates liver carcinogenesis under diabetic conditions. PMID:22261820

  3. Upper air teleconnections to Ob River flows and tree rings

    Meko, David; Panyushkina, Irina; Agafonov, Leonid

    2015-04-01

    The Ob River, one of the world's greatest rivers, with a catchment basin about the size of Western Europe, contributes 12% or more of the annual freshwater inflow to the Arctic Ocean. The input of heat and fresh water is important to the global climate system through effects on sea ice, salinity, and the thermohaline circulation of the ocean. As part of a tree-ring project to obtain multi-century long information on variability of Ob River flows, a network of 18 sites of Pinus, Larix, Populus and Salix has been collected along the Ob in the summers of 2013 and 2014. Analysis of collections processed so far indicates a significant relationship of tree-growth to river discharge. Moderation of the floodplain air temperature regime by flooding appears to be an important driver of the tree-ring response. In unraveling the relationship of tree-growth to river flows, it is important to identify atmospheric circulation features directly linked to observed time series variations of flow and tree growth. In this study we examine statistical links between primary teleconnection modes of Northern Hemisphere upper-air (500 mb) circulation, Ob River flow, and tree-ring chronologies. Annual discharge at the mouth of the Ob River is found to be significantly positively related to the phase of the East Atlantic (EA) pattern, the second prominent mode of low-frequency variability over the North Atlantic. The EA pattern, consisting of a north-south dipole of pressure-anomaly centers spanning the North Atlantic from east to west, is associated with a low-pressure anomaly centered over the Ob River Basin, and with a pattern of positive precipitation anomaly of the same region. The positive correlation of discharge and EA is consistent with these know patterns, and is contrasted with generally negative (though smaller) correlations between EA and tree-ring chronologies. The signs of correlations are consistent with a conceptual model of river influence on tree growth through air

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

    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

  5. An assessment of the MCNP4C weight window

    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.

  6. An assessment of the MCNP4C weight window

    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

  7. Radio observations of the CMa OB1 H II regions

    A sensitive 100 x 150 13-cm map made of the CMa OB1 H II regions' radio emission shows a strong similarity to Hα emission photographs. Sharpless 296 is shown to consist of a prominent central and western arc completed by a weaker southern loop, and with a faint northern bar. The emission is thermal, superimposed over a predominantly non-thermal background. The H142α recombination line has been detected at eight positions in S296, and in S292 and S297. The average electron temperature in S296 is 6900 +- 1300 K. The UV fluxes from the CMa OB1 stars account for the observed emission measures of the H II regions. The H142α 1sr velocities indicate that the ionized material is in contact with the molecular clouds. (author)

  8. Time base stability of ocean bottom seismometers (OBS)

    Shariat Panahi, Shahram; Manuel Lázaro, Antonio; Corrêa Alegría, Francisco

    2009-01-01

    During the past decades, Ocean Bottom Seismometers (OBS) have played a key role in permanent seismic activity monitoring at sea as well as allowing a better understating of the earth interior. Data collected by the instrument can provide information on the ocean bottom sub-layers down to a depth of 40 km beneath the ocean floor. The accuracy of the results directly depends on the temperature stability of the crystal used as the main time base of the equipment. This paper pre...

  9. Ensuring QOS Gurantees in a hybrid OCS/OBS Network

    Sunish Kumar O S

    2012-01-01

    The bursting aggregation assembly in edge nodes is one of the key technologies in OBS (Optical Burst Switching) network, which has a direct impact on flow characteristics and packet loss rate. An opticalburst assembly technique supporting QoS is presented through this paper, which can automatically adjust the threshold along with the increasing and decreasing volume of business, reduce the operational burst, and generate corresponding BDP (Burst Data Packet) and BCP (Burst Control Packet). ...

  10. Ensuring QOS Guarantees in a Hybrid OCS/OBS Network

    S, Sunish Kumar O

    2012-01-01

    The bursting aggregation assembly in edge nodes is one of the key technologies in OBS (Optical Burst Switching) network, which has a direct impact on flow characteristics and packet loss rate. An optical burst assembly technique supporting QoS is presented through this paper, which can automatically adjust the threshold along with the increasing and decreasing volume of business, reduce the operational burst, and generate corresponding BDP (Burst Data Packet) and BCP (Burst Control Packet). I...

  11. Fault Tolerant Congestion based Algorithms in OBS Network

    Hardeep Singh

    2011-12-01

    Full Text Available In Optical Burst Switched networks, each light path carry huge amount of traffic, path failures may damage the user application. Hence fault-tolerance becomes an important issue on these networks. Blocking probability is a key index of quality of service in Optical Burst Switched (OBS network. The Erlang formula has been used extensively in the traffic engineering of optical communication to calculate the blocking probability. The paper revisits burst contention resolution problems in OBS networks. When the network is overloaded, no contention resolution scheme would effectively avoid the collision and cause blocking. It is important to first decide, a good routing algorithm and then to choose a wavelength assignment scheme. In this paper we have developed two algorithms, Fault Tolerant Optimized Blocking Algorithm (FTOBA and Fault Tolerant Least Congestion Algorithm (FTLCA and then compare the performance of these algorithms on the basis of blocking probability. These algorithms are based upon the congestion on path in OBS network and based on the simulation results, we shows that the reliable and fault tolerant routing algorithms reduces the blocking probability.

  12. Analiza posedanja magnetno občutljivih mikrodelcev in določitev magnetne občutljivosti

    Černec, Dean

    2016-01-01

    Magistrska naloga podaja izsledke eksperimentov s posedanjem magnetno občutljivih mikrodelcev. Pri raziskavah, katerih namen je ugotavljanje različnih fizikalnih lastnosti delcev, se v praksi pogosto uporabljajo sedimentacijski procesi. Če se delci pri posedanju odzivajo tudi na delovanje zunanjega magnetnega polja, pa lahko določamo tudi njihove magnetne lastnosti. Začetne analize so bile narejene na podlagi eksperimentov s posedanjem steklenih kroglic, za kontrolo končnih hitrosti posedanja...

  13. Cygnus OB2 DANCe: A high-precision proper motion study of the Cygnus OB2 association

    Wright, Nicholas J.; Bouy, Herve; Drew, Janet E.; Sarro, Luis Manuel; Bertin, Emmanuel; Cuillandre, Jean-Charles; Barrado, David

    2016-08-01

    We present a high-precision proper motion study of 873 X-ray and spectroscopically selected stars in the massive OB association Cygnus OB2 as part of the DANCe project. These were calculated from images spanning a 15 yr baseline and have typical precisions <1 mas yr-1. We calculate the velocity dispersion in the two axes to be σ _α (c) = 13.0^{+0.8}_{-0.7} and σ _δ (c) = 9.1^{+0.5}_{-0.5} km s-1, using a two-component, two-dimensional model that takes into account the uncertainties on the measurements. This gives a three-dimensional velocity dispersion of σ3D = 17.8 ± 0.6 km s-1 implying a virial mass significantly larger than the observed stellar mass, confirming that the association is gravitationally unbound. The association appears to be dynamically unevolved, as evidenced by considerable kinematic substructure, non-isotropic velocity dispersions and a lack of energy equipartition. The proper motions show no evidence for a global expansion pattern, with approximately the same amount of kinetic energy in expansion as there is in contraction, which argues against the association being an expanded star cluster disrupted by process such as residual gas expulsion or tidal heating. The kinematic substructures, which appear to be close to virial equilibrium and have typical masses of 40-400 M⊙, also do not appear to have been affected by the expulsion of the residual gas. We conclude that Cyg OB2 was most likely born highly substructured and globally unbound, with the individual subgroups born in (or close to) virial equilibrium, and that the OB association has not experienced significant dynamical evolution since then.

  14. Mogat1 deletion does not ameliorate hepatic steatosis in lipodystrophic (Agpat2-/-) or obese (ob/ob) mice.

    Agarwal, Anil K; Tunison, Katie; Dalal, Jasbir S; Yen, Chi-Liang Eric; Farese, Robert V; Horton, Jay D; Garg, Abhimanyu

    2016-04-01

    Reducing triacylglycerol (TAG) in the liver continues to pose a challenge in states of nonalcoholic hepatic steatosis. MonoacylglycerolO-acyltransferase (MOGAT) enzymes convert monoacylglycerol (MAG) to diacylglycerol, a precursor for TAG synthesis, and are involved in a major pathway of TAG synthesis in selected tissues, such as small intestine. MOGAT1 possesses MGAT activity in in vitro assays, but its physiological function in TAG metabolism is unknown. Recent studies suggest a role for MOGAT1 in hepatic steatosis in lipodystrophic [1-acylglycerol-3-phosphateO-acyltransferase (Agpat)2(-/-)] and obese (ob/ob) mice. To test this, we deletedMogat1in theAgpat2(-/-)andob/obgenetic background to generateMogat1(-/-);Agpat2(-/-)andMogat1(-/-);ob/obdouble knockout (DKO) mice. Here we report that, despite the absence ofMogat1in either DKO mouse model, we did not find any decrease in liver TAG by 16 weeks of age. Additionally, there were no measureable changes in plasma glucose (diabetes) and insulin resistance. Our data indicate a minimal role, if any, of MOGAT1 in liver TAG synthesis, and that TAG synthesis in steatosis associated with lipodystrophy and obesity is independent of MOGAT1. Our findings suggest that MOGAT1 likely has an alternative function in vivo. PMID:26880786

  15. Effect of the Ti/B4C mole ratio on the reaction products and reaction mechanism in an Al–Ti–B4C powder mixture

    The effect of the Ti/B4C mole ratio on the fabrication behavior of Al composites is investigated using Al–Ti–B4C powder mixtures as reactants. The quick spontaneous infiltration (QSI) process combined with the combustion reaction and DTA analysis were used. According to the thermodynamic predictions, which are verified in the experimental results, TiB2 is formed in all the samples whereas TiC is only formed in reactants with a Ti/B4C mole ratio of more than two. The C atoms from the reacted B4C do not move into TiC but instead they move into Al3BC or Al4C3 when the Ti/B4C mole ratio is less than two. In addition, the reaction mechanism with a Ti/B4C mole ratio of 0.75 is investigated extensively. - Highlights: • The critical role of the Ti/B4C mole ratio on the reaction products of Al–Ti–B4C was studied using experiments. • The experimental results are also supported by thermodynamic calculations presented in this paper. • The reaction mechanism with a Ti/B4C mole ratio of 0.75 is investigated extensively

  16. Optical and radio properties of 4C galaxies

    The relations between the optical and radio properties of a sample of 4C radio galaxies of intermediate radio luminosity have been investigated. Optical spectra were taken with the Hale 5-m telescope and radio maps of a subset of the galaxies were made with the Cambridge 1-mile and 5-km telescopes. The optical activity of the nuclear region was characterized by the strength of the emission lines and by the luminosity of the non-thermal component obtained from a decomposition of the optical continuum into a non-thermal power law and the spectrum of a giant elliptical galaxy. The percentage of sources showing strong emission features is markedly less than for high-luminosity objects. The radio morphology appears to be closely related to the degree of optical activity, in that classical double sources have high activity whereas complex radio sources show little or no activity. This correlation is discussed in terms of (1) an intrinsic relationship between the energy spectrum of the relativistic electrons in the nucleus and the optical and radio properties of the galaxy, and (2) the modifications of this relationship due to the motion of the galaxy through the intergalactic medium. (author)

  17. Stress evolution in B4C and Cr mono-layer and B4C/Cr multilayer films with variable layer thickness for neutron detectors

    A serial of Cr-, B4C-monolayer and B4C/Cr multilayer films with variable layer thickness were deposited on BK-7 glass substrates using magnetron sputtering to study the stress evolution by detecting the changes of the substrate curvature with the optical interferometry technique. The stress of Cr-monolayer is tensile and decreases as its thickness increases, while the stress of B4C-monolayer is compressive and almost independent on its thickness. The residual stresses of B4C/Cr multilayer films are dependent not only on the stresses of B4C and Cr layers, but also on the interface stress between two neighboring layers. If the B4C layer thickness is kept constant, the stresses of B4C/Cr multilayer films change from compressive to tensile with the increasing of Cr layer thickness. Based on the theoretical analysis, the interface stress is mostly affected by the thickness of B4C layer and nearly negligible on the thickness of Cr layer. When the thicknesses of B4C and Cr layers are both 60 nm, the multilayer has very low residual stress, even with the period up to 17. - Highlights: ► The low residual stress of thick B4C film is achieved by inserting the Cr layers. ► The residual stresses of B4C/Cr multilayer films depend on their interface stress. ► The interface stress is dependent on the B4C layer thickness in multilayer. ► The interface stress is independent on the Cr layer thickness in multilayer

  18. X-ray properties and interface study of B{sub 4}C/Mo and B{sub 4}C/Mo{sub 2}C periodic multilayers

    Choueikani, F. [Univ Paris Sud, Laboratoire Charles Fabry, Institut d' Optique, CNRS, Palaiseau Cedex (France); Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, Gif-sur-Yvette (France); Bridou, F.; Meltchakov, E.; Delmotte, F. [Univ Paris Sud, Laboratoire Charles Fabry, Institut d' Optique, CNRS, Palaiseau Cedex (France); Lagarde, B.; Polack, F.; Mercere, P. [Synchrotron SOLEIL, L' Orme des Merisiers, Saint-Aubin, BP48, Gif-sur-Yvette (France)

    2013-04-15

    We present a comparative study of B{sub 4}C/Mo and B{sub 4}C/Mo{sub 2}C 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 B{sub 4}C-on-Mo interface in the B{sub 4}C/Mo system. Thus, the B{sub 4}C/Mo multilayers were modeled by an asymmetric structure with three layers in each period. The thickness of B{sub 4}C-on-Mo interfacial layer was estimated about 1.1 nm. The B{sub 4}C/Mo{sub 2}C multilayers present less interdiffusion and are well modeled by a symmetric structure without interfacial layers. This study shows that B{sub 4}C/Mo{sub 2}C structure is an interesting alternative to B{sub 4}C/Mo multilayer for X-ray optic applications. (orig.)

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

    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.

  20. The object SNO 74 in the association Ara OB 1

    Gyulbudaghian, A. L.

    2013-06-01

    The star formation region SNO 74 embedded in a dark cloud in the association Ara OB 1 is studied. This object is coupled to a compact HII region visible in the IR and to a close cluster of IR stars. 12CO(1-0) observations reveal the existence of red and blue molecular outflows; i.e., this is a bipolar outflow. An image taken with the SIMBA detector at 1.2 mm contains a second active region and a bridge lying to the W of the first active region and accompanied by strong absorption. The red molecular outflow is directed toward this second active region and the bridge.

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

    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.

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

    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.

  3. Fabrication and evaluation of B4C/Cu FGM as plasma facing materials

    B4C is a promising candidate for using as plasma-facing material in fusion devices. In this paper, both B4C/Cu coating FGM (Functionally graded material) and B4C/Cu bulk FGM containing a spectrum of 0-100% compositional distributions of B4C were fabricated by atmosphere plasma spray and ultra-high pressure consolidation respectively. The microstructure of B4C/Cu FGM showed good graded composition distribution. Water quenching and high heat loading experiments using an electron beam were carried out to evaluate the high heat load resistance of B4C/Cu FGMs. The in situ plasma irradiation in a Tokamak facility showed that the B4C/Cu bulk FGM has higher physical sputtering performance than that of B4C/Cu coating FGM. (orig.)

  4. TAKTIKA OB PREKINITVAH IGRE PRI MLAJŠIH SELEKCIJAH U9 - U15

    Kolar, Borut

    2014-01-01

    V diplomskem delu Taktika ob prekinitvah igre pri mlajših selekcijah U9 – U15 sem predstavil, prikazal in raziskal problem ob prekinitvah igre pri nogometu. Z nalogo sem hotel zbrati vaje za urjenje taktike ob prekinitvah igre in jih razvrstiti po težavnosti in po starostnih kategorijah od U9 do U15, da bi bile trenerjem v pomoč pri treniranju. Pomembnosti taktike ob prekinitvah igre ni treba posebej izpostavljati, saj vemo, da se v sodobnem nogometu veliko zadetkov doseže prav iz prekinitev...

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

    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

  6. The Massive Star Population of Cygnus OB2

    Wright, Nicholas J; Mohr-Smith, Michael

    2015-01-01

    We have compiled a significantly updated and comprehensive census of massive stars in the nearby Cygnus OB2 association by gathering and homogenising data from across the literature. The census contains 169 primary OB stars, including 52 O-type stars and 3 Wolf-Rayet stars. Spectral types and photometry are used to place the stars in a Hertzprung-Russell diagram, which is compared to both non-rotating and rotating stellar evolution models, from which stellar masses and ages are calculated. The star formation history and mass function of the association are assessed, and both are found to be heavily influenced by the evolution of the most massive stars to their end states. We find that the mass function of the most massive stars is consistent with a `universal' power-law slope of Gamma = 1.3. The age distribution inferred from stellar evolutionary models with rotation and the mass function suggest the majority of star formation occurred more or less continuously between 1 and 7 Myr ago, in agreement with studi...

  7. Ensuring QOS Gurantees in a hybrid OCS/OBS Network

    Sunish Kumar O S

    2012-04-01

    Full Text Available The bursting aggregation assembly in edge nodes is one of the key technologies in OBS (Optical Burst Switching network, which has a direct impact on flow characteristics and packet loss rate. An opticalburst assembly technique supporting QoS is presented through this paper, which can automatically adjust the threshold along with the increasing and decreasing volume of business, reduce the operational burst, and generate corresponding BDP (Burst Data Packet and BCP (Burst Control Packet. In addition to theburst aggregation technique a packet recovery technique by restoration method is also described. The data packet loss due to the physical optical link failure is not currently included in the QoS descriptions. This link failure is also a severe problem which reduces the data throughput of the transmitter node. A mechanism for data recovery from this link failure is vital for guaranteeing the QoS demanded by each user. So this paper will also discusses a specific protocol for reducing the packet loss by utilizing the features of both optical circuit switching (OCS and Optical Burst switching (OBS techniques.

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

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

    2009-01-01

    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...

  9. Physical evidence for a Saccharomyces cerevisiae transposable element which carries the his4C gene.

    de Bruijn, F; Greer, H

    1981-01-01

    A Saccharomyces cerevisiae transposable element which carries the his4C structural gene and which is capable of transposition, excision, and mutator activity is described. Physical evidence is presented for transposition of the his4C deoxyribonucleic acid sequences to a new location in the genome and for precise excision of these transposed deoxyribonucleic acid sequences in spontaneous his4C- segregants.

  10. The Luminosity Function of OB Associations in the Galaxy

    McKee, Christopher F.; Williams, Jonathan P.

    1997-02-01

    OB associations ionize the interstellar medium, producing both localized H II regions and diffuse ionized gas. The supernovae resulting from these associations pressurize and stir the interstellar medium. Using Smith, Biermann, & Mezger's compilation of radio H II regions in the Galaxy, and Kennicutt, Edgar, & Hodge's optical study of H II regions in nearby galaxies, we show that the luminosity distribution of giant OB associations in the Galaxy can be fit by a truncated power law of the form \\Nscra(>S)=\\Nscrau[(Su/S)-1], where S is the ionizing photon luminosity, \\Nscra(>S) is the number of associations with a luminosity of at least S, and Su is the upper limit to the distribution. The coefficient \\Nscrau is the number of the most luminous associations, with a luminosity between 0.5Su and Su. For the Galaxy, \\Nscrau=6.1 the fact that the number of the most luminous associations is significantly larger than unity indicates that there is a physical limit to the maximum size of H II regions in the Galaxy. To extend the luminosity distribution to small H II regions, we assume that the birthrate of associations, \\Nscr\\dota(>\\Nscr*), is also a truncated power law, \\Nscr\\dota(>\\Nscr*)~[(\\Nscr*u/\\Nscr*)-1], where \\Nscr* is the number of stars in the association. For large associations, the ionizing luminosity is proportional to the number of stars, S~\\Nscr* for smaller associations, we use both an analytic and a Monte Carlo approach to find the resulting luminosity distribution \\Nscra(>S). H II regions are generally centrally concentrated, with only the dense central regions being bright enough to appear in radio catalogs. Anantharamaiah postulated that radio H II regions have extended envelopes in order to account for diffuse radio recombination line emission in the Galaxy. Some of these envelopes are visible as the ionized ``worms'' discussed by Heiles and coworkers. We estimate that on the average the envelopes of radio H II regions absorb about twice

  11. Decreased triiodothyronine receptor binding in skeletal muscle nuclei and erythrocyte membranes of obese (ob/ob) mice

    Hindlimb skeletal muscle weights and binding of L-tri-iodothyronine (T3) to isolated nuclei of this tissue were investigated in obese (ob/ob) mice and their lean littermates. Maximal binding capacities (Bmax) and dissociation constants (Kd) were determined by incubating isolated muscle nuclei with increasing conc. of 125I-T3 (0.4 nM to 4nM). At 12 wks. of age, although weighing substantially more, obese mice had only 55% as much muscle mass as their lean littermates. There was no phenotype effect observed for Kd, however, Bmax was significantly less for the obese mice. In a second experiment, a 16-wk. feeding study was conducted with 4 groups of mice according to the following design: lean mice fed rodent chow; obese mice fed rodent chow; obese mice, n-6 fatty acid (FA)-rich diet; and obese mice, n-3FA-rich diet. Erythrocyte T3 receptor binding capacities were measured by incubating red cell ghosts from mice of these 4 groups with 125I-T3. As with skeletal muscle nuclei there were no phenotype effects observed for Kd between any two groups. In contrasts obese mice fed chow and n-6FA-rich diets both exhibited lower Bmax than their lean counterparts, while no significant difference was observed between the latter group and the obese mice fed an n-3FA-rich diet. Bmax values of the n-6 group were also decreased compared to the n-3 group

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

    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 ...

  13. LXR activation by GW3965 alters fat tissue distribution and adipose tissue inflammation in ob/ob female mice[S

    Archer, Amena; Stolarczyk, Émilie; Doria, Maria Luisa; Helguero, Luisa; Domingues, Rosário; Howard, Jane K; Mode, Agneta; Korach-André, Marion; Gustafsson, Jan-Åke

    2013-01-01

    To investigate the role of liver X receptor (LXR) in adipose tissue metabolism during obesity, ob/ob mice were treated for 5 weeks with the synthetic LXR agonist GW3965. MRI analysis revealed that pharmacological activation of LXR modified fat distribution by decreasing visceral (VS) fat and inversely increasing subcutaneous (SC) fat storage without affecting whole body fat content. This was concordant with opposite regulation by GW3965 of the lipolytic markers hormone-sensitive lipase (HSL) ...

  14. Association between diencephalic thyroliberin and arterial blood pressure in agouti-yellow and ob/ob mice may be mediated by leptin.

    Burgueño, Adriana L; Landa, Maria S; Schuman, Mariano L; Alvarez, Azucena L; Carabelli, Julieta; García, Silvia I; Pirola, Carlos J

    2007-10-01

    Leptin, a hormone secreted by the adipose tissue, stimulates anorexigenic peptides and also inhibits orexigenic peptides in hypothalamic arcuate nuclei-located neurons. It also counteracts the starvation-induced suppression of thyroid hormones by up-regulating the expression of preproTRH gene. On the other hand, in addition to its role as a modulator of the thyroid-hypothalamic-hypophysial axis, thyrotropin-releasing hormone (TRH) acts as a modulator of the cardiovascular system. In fact, we reported that overexpression of diencephalic TRH (dTRH) induces hypertension. We have recently shown that, in rats with obesity-induced hypertension, hyperleptinemia may produce an increase of dTRH together with an elevation of arterial blood pressure (ABP) through an increase of sympathetic activity and that these alterations were reversed by antisense oligonucleotide and small interfering RNA against preproTRH treatments. Here we explore the possible role of dTRH as a mediator involved in leptin-induced hypertension in 2 obesity mouse models: agouti-yellow mice, which are hyperleptinemic and hypertensive, and ob/ob mice, which lack functional circulating leptin. These 2 models share some characteristics, but ob/ob mice show lower ABP and plasma catecholamines levels. Then, for the first time, we report that there is a clear association between ABP and dTRH levels in both mouse models, as we have found that dTRH content was elevated in agouti-yellow mice and diminished in ob/ob mice compared with their controls. We also show that, after 3 days of subcutaneous leptin injections (10 microg/12 hours), ABP and dTRH increased significantly in ob/ob mice with no alterations of thyroid hormone levels. These results add evidence to the putative molecular mechanisms for the strong association between obesity and hypertension. PMID:17884458

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

    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.

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

    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.

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

    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.

  18. Glacier Area and River Runoff Changes in the Head of Ob River Basins During the Last 50 Years

    Surazakov, A. B.; Aizen, V. B.; Aizen, E. M.; Nikitin, S. A.; Narojniy, J. K.

    2006-12-01

    The Altai mountains in Siberia define southern periphery of the Asian Arctic Basin, and the Ob River is a major Siberian river fed by fresh water from Altai glaciers. Intensification of glacier melt in the head of Ob River since the middle of 20th century may have a considerable influence on the water resources and hydrological regime of Siberian rivers, and freshwater budget of the Arctic Ocean. In our research we estimated glacier area and runoff changes in the Aktru River basin (34.9 km2, 45% covered by glaciers) in the Central Altai using remote sensing data and in situ glaciological and hydrological observations. The measurements of the glacier mass-balance started in this basin in 1952 as a part of the World Glacier Monitoring Service, however an accurate estimation of the glacier area change in the last two decades have not been accomplished. In our research we used aerial photographs (1952, 1975), Corona (1968) and ASTER (2004) images, and Ground Control Points collected with DGPS in 2005 and 2006 field surveys. Preliminary analysis shows that area of the studied glaciers reduced up to 7% and glacier tongues retreated up to 600 m from 1952 to 2004. The rate of the glacier recession doubled between 1975 and 2004 and the river runoff increased by 30 mm/year at the head of Ob river tributaries fed by snow and glacier melt water. During the period from 1954 to 2004 annual (mainly summer) air temperature increased by 0.1 C° a decade and precipitation (mainly spring and summer) increased by 50 mm at an elevation of 2000 m.

  19. A Cornucopia of Massive Binary Star Systems in the Cygnus OB2 Association: Fifty and Counting

    Kobulnicky, Henry A.; Kiminki, D. C.; Burke, J. F.; Chapman, J. E.; Keller, E.; Lester, K. V.; Rolen, E.; Topel, E.; Lundquist, M. J.; Bhattacharjee, A.; Vargas Alvarez, C. A.; Runnoe, J. C.; Dale, D. A.

    2014-01-01

    Massive binary star systems produce nature's most energetic events, including some classes of supernovae, gamma-ray bursts, X-ray binaries, and double-degenerate objects that generate gravitational wave radiation. The Cygnus OB2 Association is the largest nearby collection of massive stars, consisting of several hundred O and early B stars at a distance of just 1.4 kpc. Our Cygnus OB2 Radial Velocity Survey team at the University of Wyoming has spectroscopically monitored 115 stars of type B2 or earlier between 1999 and 2013, accruing an average of 12 observations per star at a velocity precision of 2-6 km/s. We have identified fifty massive binary systems, nearly all of which have full orbital solutions. Periods range from 1.4 days - 12.5 years and velocity semi-amplitudes span 4-300 km/s. Monte-Carlo modeling indicates that as many as 90% of massive systems contain multiple stars and that 45% of these can be characterized as ``close'' binaries that will interact, exchanging matter during main-sequence or post-main-sequence evolution. Statistical analysis of the orbital parameters reveals a striking surplus of close, short-period systems with periods P=1.4--7 days, with fully 30% (17 out of 50 systems) of the known binaries falling in this tight range; their typical orbital separations are just a small fraction of an astronomical unit. The remainder of the binary systems are consistent with a period distribution described as flat in log(P) out to several thousand day periods. The mass ratio distribution appears flat over the interval q=M2/M1=0.1-1.0, meaning that massive stars preferentially have massive companions. These data constitute the largest and most complete homogeneous database on any single collection of massive stars in a common formation environment covering the full range of stars expected to explode as supernovae (B2V and earlier). As such, the Survey provides the raw data for modeling rates of cosmic supernova, gamma-ray bursts, and X-ray binaries

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

    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.

  1. EC 11481-2303 - A Peculiar Subdwarf OB Star Revisited

    Rauch, T; Kruk, J W

    2010-01-01

    EC 11481-2303 is a peculiar, hot, high-gravity pre-white dwarf. Previous optical spectroscopy revealed that it is a sdOB star with an effective temperature (Teff) of 41790 K, a surface gravity log(g)= 5.84, and He/H = 0.014 by number. We present an on-going spectral analysis by means of non-LTE model-atmosphere techniques based on high-resolution, high-S/N optical (VLT-UVES) and ultraviolet (FUSE, IUE) observations. We are able to reproduce the optical and UV observations simultaneously with a chemically homogeneous NLTE model atmosphere with a significantly higher effective temperature and lower He abundance (Teff = 55000 K, log (g) = 5.8, and He / H = 0.0025 by number). While C, N, and O appear less than 0.15 times solar, the iron-group abundance is strongly enhanced by at least a factor of ten.

  2. 3D MHD simulations of subsurface convection in OB stars

    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...

  3. The OB association LH 58 in the Large Magellanic Cloud

    Garmany, Catharine D.; Massey, Philip; Parker, Joel WM.

    1994-01-01

    We present charge coupled device (CCD) photometry and spectroscopy for stars in Lucke-Hodge 58, an isolated OB association in the Large Magellanic Cloud (LMC) northwest of 30 Doradus. The photometric catalog contains 839 stars with UBV magnitudes complete to V approximately = 19. We have obtained spectra and classified 35 stars; combined with previous published spectral types, we find 22 O-type stars. The earliest type is O3-4 V, and there are three Wolf-Rayet (WR) stars in the association. The slope of the initial mass function, Gamma = -1.7 +/- 0.3, is in good agreement with other LMC associations. The presence of several evolved supergiants with masses about 15-25 solar mass suggests that some star formation took place as early as 10 million years ago, but the majority of stars formed coevally within the past few million years.

  4. Hormone-sensitive lipase deficiency suppresses insulin secretion from pancreatic islets of Lepob/ob mice

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

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

    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}.

  6. Acquisition of Multicomponent-4C Seismic Data from Unconventional Marine Reservoirs to Improve Exploration and Risk Attenuation in Reservoir Characterization

    Aluka, I. J.

    2013-12-01

    The move to explore for commercial oil and gas from unconventional reservoirs such as shale/mudstone and tight gas sand reservoirs is having serious technical challenges. Multicomponent- 4C seismic data acquisition in marine settings will go a long way to assist oil and gas companies to discover unconventional resources with significant commercial value in the marine environments. Multicomponent technology has been proved to be effective in exploration and reservoir characterization and risk reduction. The technology provides enhanced strata images by reflecting independent subsurfaces, direct lithofacies and hydrocarbon indication compared to only conventional P-wave seismic stratigraphy. Multi component seismic data can be acquired in the marine settings by utilizing energy from towed air-gun arrays, and 4-component ocean bottom sensor (4-C OBS) packages deployed on the seafloor. Because the S waves do not travel through liquids, the sensors have to be deployed on the seafloor. The 4-component ocean bottom sensor comprises of a hydrophone, a gimbaled 3-component geophone as opposed to ungimbaled 3-component geophone. This gimbaled 3-component geophone is continually rotated by gravity to make sure that the moving-coil elements are placed in the crossline horizontal, and vertical, inline horizontal directions. Two or more vessels are used in marine multicompnent data acquisition. One vessel is a source vessel and the others are connected to the seafloor cable and record the 4-C seismic data. Every receiver on the seafloor is composed of a single 4-C sensor package, which is stationary during data recording. P-wave data are combination of particle-velocity wavefield recorded by the vertical geophone and pressure wavefield recorded by the hydrophone. The inline and crossline horizontal geophones record the particle-velocity data which are used to generate the upgoing reflected SV wavefield arriving at the seafloor. The downgoing P wavefield at non normal angles of

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

    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...

  8. Pressure effect on structural, elastic, and thermodynamic properties of tetragonal B4C4

    The compressibility, elastic anisotropy, and thermodynamic properties of the recently proposed tetragonal B4C4 (t-B4C4) are investigated under high temperature and high pressure by using of first-principles calculations method. The elastic constants, bulk modulus, shear modulus, Young’s modulus, Vickers hardness, Pugh’s modulus ratio, and Poisson’s ratio for t-B4C4 under various pressures are systematically explored, the obtained results indicate that t-B4C4 is a stiffer material. The elastic anisotropies of t-B4C4 are discussed in detail under pressure from 0 GPa to 100 GPa. The thermodynamic properties of t-B4C4, such as Debye temperature, heat capacity, and thermal expansion coefficient are investigated by the quasi-harmonic Debye model

  9. Pressure effect on structural, elastic, and thermodynamic properties of tetragonal B4C4

    Baobing Zheng

    2015-03-01

    Full Text Available The compressibility, elastic anisotropy, and thermodynamic properties of the recently proposed tetragonal B4C4 (t-B4C4 are investigated under high temperature and high pressure by using of first-principles calculations method. The elastic constants, bulk modulus, shear modulus, Young’s modulus, Vickers hardness, Pugh’s modulus ratio, and Poisson’s ratio for t-B4C4 under various pressures are systematically explored, the obtained results indicate that t-B4C4 is a stiffer material. The elastic anisotropies of t-B4C4 are discussed in detail under pressure from 0 GPa to 100 GPa. The thermodynamic properties of t-B4C4, such as Debye temperature, heat capacity, and thermal expansion coefficient are investigated by the quasi-harmonic Debye model.

  10. Globules and pillars in Cygnus X. I. Herschel far-infrared imaging of the Cygnus OB2 environment

    Schneider, N.; Bontemps, S.; Motte, F.; Blazere, A.; André, Ph.; Anderson, L. D.; Arzoumanian, D.; Comerón, F.; Didelon, P.; Di Francesco, J.; Duarte-Cabral, A.; Guarcello, M. G.; Hennemann, M.; Hill, T.; Könyves, V.; Marston, A.; Minier, V.; Rygl, K. L. J.; Röllig, M.; Roy, A.; Spinoglio, L.; Tremblin, P.; White, G. J.; Wright, N. J.

    2016-06-01

    The radiative feedback of massive stars on molecular clouds creates pillars, globules and other features at the interface between the H II region and molecular cloud. Optical and near-infrared observations from the ground as well as with the Hubble or Spitzer satellites have revealed numerous examples of such cloud structures. We present here Herschel far-infrared observations between 70 μm and 500 μm of the immediate environment of the rich Cygnus OB2 association, performed within the Herschel imaging survey of OB Young Stellar objects (HOBYS) program. All of the observed irradiated structures were detected based on their appearance at 70 μm, and have been classified as pillars, globules, evaporating gasous globules (EGGs), proplyd-like objects, and condensations. From the 70 μm and 160 μm flux maps, we derive the local far-ultraviolet (FUV) field on the photon dominated surfaces. In parallel, we use a census of the O-stars to estimate the overall FUV-field, that is 103-104 G0 (Habing field) close to the central OB cluster (within 10 pc) and decreases down to a few tens G0, in a distance of 50 pc. From a spectral energy distribution (SED) fit to the four longest Herschel wavelengths, we determine column density and temperature maps and derive masses, volume densities and surface densities for these structures. We find that the morphological classification corresponds to distinct physical properties. Pillars and globules are massive (~500 M⊙) and large (equivalent radius r ~ 0.6 pc) structures, corresponding to what is defined as "clumps" for molecular clouds. EGGs and proplyd-likeobjects are smaller (r ~ 0.1 and 0.2 pc) and less massive (~10 and ~30 M⊙). Cloud condensations are small (~0.1 pc), have an average mass of 35 M⊙, are dense (~6 × 104 cm-3), and can thus be described as molecular cloud "cores". All pillars and globules are oriented toward the Cyg OB2 association center and have the longest estimated photoevaporation lifetimes, a few million

  11. 32 CFR 1630.42 - Class 4-C: Alien or dual national.

    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...

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

    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...

  13. A WISE Census of Young Stellar Objects in Perseus OB2 Association

    Azimlu, Mohaddesseh; Muench, August A

    2015-01-01

    We have performed a WISE (Wide-Field Infrared Survey Explorer) based study to identify and characterize young stellar objects (YSOs) in 12x12 degree Perseus OB2 association. Spectral energy distribution (SED) slope in range of 3.4-12 micron and a 5sigma selection criteria were used to select our initial sample. Further manual inspection reduced our final catalog to 156 known and 119 YSO candidate. The spatial distribution of newly found YSOs all over the field shows an older generation of star formation which most of its massive members have evolved into main sequence stars. In contrast, the majority of younger members lie within the Perseus molecular cloud and currently active star forming clusters such as NGC1333 and IC348. We also identified additional 66 point sources which passed YSO selection criteria but are likely AGB stars. However their spatial distribution suggests that they may contain a fraction of the YSOs. Comparing our results with the commonly used color-color selections, we found that while ...

  14. La Asociación OB Bochum7 combinando datos IR y ópticos

    Corti, M. A.; Bosch, G. L.; Niemela, V. S.

    We present the results of an analysis of IR data in the region of the galactic OB association Bo7, obtained from the archives of the IRAS satellite mission and the 2MASS survey. Bo7 is located at the end of Perseus spiral arm. Distances of possible members of the Bo7 association were determined calculating the absorption from the E(V-K) colour excess. These members had been previously selected according to their UBV colours and spectra. The distance values obtained with IR excess have a smaller error than those obtained considering the E(B-V) excess. An extended interstellar dust cloud (detected in IRAS maps) is found to be probably associated with the members of Bo7. Two IRAS point sources observed in the region have characteristics of star formation sites. One of these point sources has been observed in CS(2-1) by Bronfman et al. (1996), who determined a value of (LSR) velocity of 44 km/s, close to the velocity of stars in Bo7 (Corti et al. 2003). A group of main sequence O - B0.5 stars appear near the location of the aforementioned IRAS point source, suggesting sequential star formation in the Bo7 region.

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

    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...

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

    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.

  17. Design, Synthesis, and Application of OB2C Combinatorial Peptide and Peptidomimetic Libraries

    Liu, Ruiwu; Shih, Tsung-Chieh; Deng, Xiaojun; Anwar, Lara; Ahadi, Sara; Kumaresan, Pappanaicken; Lam, Kit S.

    2015-01-01

    The “one-bead two-compound” (OB2C) combinatorial library is constructed on topologically segregated trifunctional bilayer beads such that each bead has a fixed cell-capturing ligand and a random library compound co-displayed on its surface and a chemical coding tag (bar code) inside the bead. An OB2C library containing thousands to millions of compounds can be synthesized and screened concurrently within a short period of time. When live cells are incubated with such OB2C libraries, every bead will be coated with a monolayer of cells. The cell membranes of the captured cells facing the bead surface are exposed to the library compounds tethered to each bead. A specific biochemical or cellular response can be detected with an appropriate reporter system. The OB2C method enables investigators to rapidly discover synthetic molecules that not only interact with cell-surface receptors but can also stimulate or inhibit downstream cell signaling. To demonstrate this powerful method, one OB2C peptide library and two OB2C peptidomimetic libraries were synthesized and screened against Molt-4 lymphoma cells to discover “death ligands.” Apoptosis of the bead-bound cells was detected with immunocytochemistry using horseradish peroxidase (HRP)-conjugated anti-cleaved caspase-3 antibody and 3,3′-diaminobenzidine as a substrate. Two novel synthetic “death ligands” against Molt-4 cells were discovered using this OB2C library approach. PMID:25616322

  18. Comparison of nanostructured Al/B4C composite produced by ARB and Al/B4C composite produced by RRB process

    Research highlights: → The SEM microstructures revealed the well distributed B4C particles in the aluminum matrix for both the composites. → The TEM analysis showed the nanostructured Al/B4C composite was produced by the ARB process successfully. → The ductility (elongation) of the RRB processed composite is higher than that of the ARB processed composite. → The microhardness of the ARB processed composite is higher than that of the RRB processed composite. - Abstract: In the present study, Al/B4C composites were produced and compared in the form of sheets, through accumulative roll bonding (ARB) and repeated roll bonding (RRB) processes. The microstructure of the composites fabricated by both the methods, revealed by scanning electron microscopy (SEM), showed the B4C particles properly distributed in the aluminum matrix. The average grain size of the ARB processed composite was about 186 nm by linear intercept method, based on transmission electron microscopy (TEM) observations. Mechanical properties of the Al/B4C composites produced by two methods were investigated by tensile and hardness tests. The results showed that the tensile strength and hardness of the ARB and RRB processed composites increase with the number of cycles. However, the tensile strength and hardness of the ARB processed composite are much higher than those of the RRB processed composite. The tensile test results revealed that the elongation of the ARB processed composite is lower than that of the RRB processed composite.

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

    Pilely, Katrine; Skjoedt, Mikkel-Ole; Nielsen, Christian; Andersen, Thomas Emil; Åbom, Anne; Vitved, Lars; Koch, Claus; Skjødt, Karsten; Palarasah, Yaseelan

    2014-01-01

    The increasing evidence of the implication of the complement system in the pathogenesis of several diseases has emphasized the need for the development of specific and valid assays, optimized for quantitative detection of complement activation in vivo. In the present study, we have developed a...... 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-cleaved) C4, C4b, iC4b, or C4d. Also, no reaction was observed with C4 fragments in factor I deficient plasma or serum samples. We established and validated a sandwich ELISA based on this C4c specific antibody. The normal range of C4c in EDTA/futhan plasma collected from 100 Danish blood...

  20. Heat release from B4C oxidation in steam and air

    BWR and some PWR cores contain boron carbide (B4C) as neutron absorber. During a severe accident, the B4C can potentially react with steam under release of heat and hydrogen. Although models for B4C oxidation already exist in MELCOR and SCDAP/RELAP5, a development of a new model for another computer code seems to be difficult due to a missing comprehensive description of the current modelling methodology and scarce experimental data. The aim of this paper is to highlight the key points of the B4C oxidation using the existing available experimental data and to perform a simple heat balance analysis of the B4C/steam and B4C/air chemical reactions. The analysis of literature data shows that the B4C oxidation phenomenon is qualitatively well described below 1000 deg. C. However, no reliable data exist for the reaction kinetics especially above this temperature. It was found that the experimental results strongly depend on the experimental arrangement. The reaction heats, calculated in this study, indicate that the B4C oxidation is an exothermic reaction, releasing more heat in air than in steam. The formation of boric acids from the boron oxide increases the heat release from B4C by ∼ 10%, in the worst case. Although the total heat, released in a PWR core from the B4C oxidation, is probably much smaller than the heat released from the Zr/steam reaction, it is not excluded that the B4C oxidation can locally contribute to the damage of the control elements due to local overheating. Modelling of these phenomena is, however, very difficult due to the complex geometry of the liquefied control elements and due to absence of suitable data on the reaction kinetics. (author). 25 refs, 2 figs, 3 tabs

  1. COSMIC ORIGINS SPECTROGRAPH OBSERVATIONS OF TRANSLUCENT CLOUDS: Cyg OB2 8A

    Data from the Cosmic Origins Spectrograph (COS) are presented for the first highly reddened target (Cyg OB2 8A) under the COS Science Team's guaranteed time allocation. Column densities of ionic, atomic, and molecular species are reported and implications are discussed. Data from Cyg OB2 8A demonstrate the ability to analyze highly reddened interstellar sight lines with the COS that were unavailable to previous UV instruments. Measured column densities indicate that the Cyg OB2 8A line of sight contains multiple diffuse clouds rather than a dominant translucent cloud.

  2. Impairment-aware QoS provisioning in dual-header OBS networks

    Yuqi Fan; Bin Wang; Lian Li

    2011-01-01

    Signal degradation due to physical impairments may result in unacceptable bit-error rates of received signals at the destination.Based on earlier work,we study the impairment-aware quality of service(QoS)provisioning problem in dual-header optical burst switching(OBS) networks that employ two control packets for each data burst.At an OBS node,the proposed algorithm schedule bursts for transmission by searching for available resources using admission control and preemption.The algorithm also verifies signal quality.Simulation results show that this algorithm is effective in providing QoS support in OBS networks while considering physical impairment effects.

  3. Enzyme kinetic studies of histone demethylases KDM4C and KDM6A

    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......, selectivity between Jumonji family histone demethylases can be obtained even with small molecule ligands....

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

    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. PMID:26413648

  5. First-principles calculations on Mg/Al4C3 interfaces

    In order to explore the interfacial structure of Mg/Al4C3 interface and clarify the heterogeneous nucleation potential of Al4C3 particles in Mg melt. The atomic structure, bonding, and interfacial energy of Mg/Al4C3 interfaces were studied by first-principles calculations to analyze the sequence of Mg atoms onto the surface of Al4C3 (0 0 0 1) slab. Surface energy calculations show that the outmost layer of Al4C3 free surface having a preference of C atom termination. And polar covalent/ionic mixed bonds are formed across interface during the combination of Mg atoms with C-terminated Al4C3 surface. The calculated interfacial energy of Mg/Al4C3 interface is much smaller than that between α-Mg and magnesium melts, proving the excellent nucleation potency of Al4C3 particles for α-Mg grains from interfacial atomic structure and atomic bonding energy considerations.

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

    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.

  7. The interstellar medium towards the Ara OB1 region

    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.

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

    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.

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

    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.

  10. Determination of the Galactic Rotation Curve from OB Stars

    Bobylev, V V

    2015-01-01

    We consider three samples of O- and B-type stars from the solar neighborhood 0.6--4 kpc for which we have taken the distances, line-of-sight velocities, and proper motions from published sources. The first sample contains 120 massive spectroscopic binaries. O stars with spectroscopic distances from Patriarchi et al. constitute the second sample. The third sample consists of 168 OB3 stars whose distances have been determined from interstellar calcium lines. The angular velocity of Galactic rotation at the solar distance $\\Omega_0,$ its two derivatives $\\Omega'_0$ and $\\Omega"_0,$ and the peculiar velocity components of the Sun $(U,V,W)_\\odot$ are shown to be well determined from all three samples of stars. They are determined with the smallest errors from the sample of spectroscopic binary stars and the sample of stars with the calcium distance scale. The fine structure of the velocity field associated with the influence of the Galactic spiral density wave clearly manifests itself in the radial velocities of s...

  11. Ensuring QOS Guarantees in a Hybrid OCS/OBS Network

    S, Sunish Kumar O

    2012-01-01

    The bursting aggregation assembly in edge nodes is one of the key technologies in OBS (Optical Burst Switching) network, which has a direct impact on flow characteristics and packet loss rate. An optical burst assembly technique supporting QoS is presented through this paper, which can automatically adjust the threshold along with the increasing and decreasing volume of business, reduce the operational burst, and generate corresponding BDP (Burst Data Packet) and BCP (Burst Control Packet). In addition to the burst aggregation technique a packet recovery technique by restoration method is also described. The data packet loss due to the physical optical link failure is not currently included in the QoS descriptions. This link failure is also a severe problem which reduces the data throughput of the transmitter node. A mechanism for data recovery from this link failure is vital for guaranteeing the QoS demanded by each user. So this paper will also discusses a specific protocol for reducing the packet loss by u...

  12. THE INITIAL MASS FUNCTION OF FIELD OB STARS IN THE SMALL MAGELLANIC CLOUD

    Some theories of star formation suggest massive stars may only form in clustered environments, which would create a deficit of massive stars in low-density environments. Observationally, Massey finds such a deficit in samples of the field population in the Small and Large Magellanic Clouds, with an initial mass function (IMF) slope of ΓIMF ∼ 4. These IMF measurements represent some of the largest known deviations from the standard Salpeter IMF slope of ΓIMF = 1.35. Here, we carry out a comprehensive investigation of the mass function above 20 M ☉ for the entire field population of the Small Magellanic Cloud (SMC), based on data from the Runaways and Isolated O Type Star Spectroscopic Survey of the SMC (RIOTS4). This is a spatially complete census of the entire field OB star population of the SMC obtained with the IMACS multi-object spectrograph and MIKE echelle spectrograph on the Magellan telescopes. Based on Monte Carlo simulations of the evolved present-day mass function, we find the slope of the field IMF above 20 M ☉ is ΓIMF = 2.3 ± 0.4. We extend our IMF measurement to lower masses using BV photometry from the OGLE II survey. We use a statistical approach to generate a probability distribution for the mass of each star from the OGLE photometry, and we again find ΓIMF = 2.3 ± 0.6 for stellar masses from 7 M ☉ to 20 M ☉. The discovery and removal of ten runaways in our RIOTS4 sample steepens the field IMF slope to ΓIMF = 2.8 ± 0.5. We discuss the possible effects of binarity and star formation history on our results, and conclude that the steep field massive star IMF is most likely a real effect.

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

    Andersson, A M; Moran, N; Gaardsvoll, H; Linnemann, D; Bjerkvig, R; Laerum, O D; Bock, Elisabeth Marianne

    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......-substratum binding assay in which the binding of BT4C and BT4Cn cells to NCAM immobilized to glass was assessed. We found thatBT4C 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...... lines thus constitute an important new model system for the study of tumor invasion and metastasis and of the role of cell adhesion molecules in these processes....

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

    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 (

  15. Study of eclipsing binary and multiple systems in ob associations. II. The cygnus ob region: V443 Cyg, V456 Cyg, and V2107 Cyg

    Bakış, V.; Bakış, H. [Faculty of Science, Department of Space Sciences and Technologies, Akdeniz University, Antalya (Turkey); Hensberge, H. [Royal Observatory of Belgium, Ringlaan 3, B-1180 Brussels (Belgium); Bilir, S. [Science Faculty, Department of Astronomy and Space Sciences, İstanbul University, 34119 University-İstanbul (Turkey); Yılmaz, F. [Physics Department, Çanakkale Onsekiz Mart University, Terzioǧlu Campus, TR-17020 Çanakkale (Turkey); Kıran, E. [Faculty of Science, Department of Astronomy and Space Sciences, Ege University, İzmir (Turkey); Demircan, O. [Department of Space Sciences and Technologies, Çanakkale Onsekiz Mart University, Terzioǧlu Campus, TR-17020 Çanakkale (Turkey); Zejda, M.; Mikulášek, Z. [Department of Theoretical Physics and Astrophysics, Masaryk University, Brno (Czech Republic)

    2014-06-01

    Three presumably young eclipsing binary systems in the direction of the Cygnus OB1, OB3, and OB9 associations are studied. Component spectra are reconstructed and their orbits are determined using light curves and spectra disentangling techniques. V443 Cyg and V456 Cyg have circular orbits while the light curve of V2107 Cyg imposes a slightly eccentric orbit (e = 0.045 ± 0.03). V443 Cyg harbors F-type stars, not young early-A stars as previously suggested in the literature based solely on photometry. It appears to be situated in the foreground (distance 0.6 ± 0.2 kpc) of the young stellar populations in Cygnus. V456 Cyg, at a distance of 0.50 ± 0.03 kpc, consists of a slightly metal-weak A-type star and an early-F star. The age of both systems, on or very near to the main sequence, remains uncertain by an order of magnitude. V2107 Cyg is a more massive system (8.9 ± 2 and 4.5 ± 1.2 M {sub ☉}) at 1.5 ± 0.5 kpc and, also kinematically, a strong candidate-member of Cyg OB1. The more massive component is slightly evolved and appears to undergo non-radial βCep-type pulsations. The Doppler signal of the secondary is barely detectable. A more extensive, asteroseismological study is necessary to fix masses more precisely. Nevertheless, the position of the primary in the H-R diagram confines the age reasonably well to 20 ± 5 Myr, indicating that for Cyg OB1 has a similar extent of star formation history as that established for Cyg OB2.

  16. Study of eclipsing binary and multiple systems in ob associations. II. The cygnus ob region: V443 Cyg, V456 Cyg, and V2107 Cyg

    Three presumably young eclipsing binary systems in the direction of the Cygnus OB1, OB3, and OB9 associations are studied. Component spectra are reconstructed and their orbits are determined using light curves and spectra disentangling techniques. V443 Cyg and V456 Cyg have circular orbits while the light curve of V2107 Cyg imposes a slightly eccentric orbit (e = 0.045 ± 0.03). V443 Cyg harbors F-type stars, not young early-A stars as previously suggested in the literature based solely on photometry. It appears to be situated in the foreground (distance 0.6 ± 0.2 kpc) of the young stellar populations in Cygnus. V456 Cyg, at a distance of 0.50 ± 0.03 kpc, consists of a slightly metal-weak A-type star and an early-F star. The age of both systems, on or very near to the main sequence, remains uncertain by an order of magnitude. V2107 Cyg is a more massive system (8.9 ± 2 and 4.5 ± 1.2 M ☉) at 1.5 ± 0.5 kpc and, also kinematically, a strong candidate-member of Cyg OB1. The more massive component is slightly evolved and appears to undergo non-radial βCep-type pulsations. The Doppler signal of the secondary is barely detectable. A more extensive, asteroseismological study is necessary to fix masses more precisely. Nevertheless, the position of the primary in the H-R diagram confines the age reasonably well to 20 ± 5 Myr, indicating that for Cyg OB1 has a similar extent of star formation history as that established for Cyg OB2.

  17. Spectroscopic Confirmation of the Dragonfish Association: The Galaxy's Most Luminosity OB Association

    Rahman, Mubdi; Matzner, Christopher D

    2011-01-01

    Young OB associations with masses greater than 10$^4$ M$_{\\sun}$ have been inferred to exist in the Galaxy but have largely evaded detection. Recently, a candidate OB association has been identified within the most luminous star forming complex in the Galaxy, the Dragonfish Nebula. We identify 18 young, massive stars with near-infrared spectroscopy from a sample of 50 members within the candidate OB association, including 15 O-type, and three Luminous Blue Variables or Wolf-Rayet stars. This number matches the expected yield of massive stars from the candidate association, confirming its existence and ability to power the parent star forming complex. These results demonstrate the existence of a 10$^5$ M$_{\\sun}$ OB association, more powerful than any previously known in the Galaxy, comparable in mass only to Westerlund 1. Further, the results also validate the color selection method used to identify the association, adding credence to others discovered in the same way.

  18. Spectroscopic Confirmation of the Dragonfish Association: The Galaxy's Most Luminous OB Association

    Rahman, Mubdi; Moon, Dae-Sik; Matzner, Christopher D.

    2011-12-01

    Young OB associations with masses greater than 104 M ⊙ have been inferred to exist in the Galaxy but have largely evaded detection. Recently, a candidate OB association has been identified within the most luminous star-forming complex in the Galaxy, the Dragonfish Nebula. We identify 18 young, massive stars with near-infrared spectroscopy from a sample of 50 members within the candidate OB association, including 15 O-type and 3 luminous blue variables or Wolf-Rayet stars. This number matches the expected yield of massive stars from the candidate association, confirming its existence and ability to power the parent star-forming complex. These results demonstrate the existence of a 105 M ⊙ OB association, more powerful than any previously known in the Galaxy, comparable in mass only to Westerlund 1. Further, the results also validate the color selection method used to identify the association, adding credence to others discovered in the same way.

  19. Gamma Ray Bursts versus OB Associations: do they trigger star formation?

    Efremov, Yu. N.; Ehlerova, S.; Palous, J.

    1999-01-01

    We discuss differences in shapes, expansion velocities and fragmentation times of structures created by an energy deposition from a single Gamma Ray Burst (GRB) or an OB association to the ISM. After the initial inflation, supershells produced by GRBs are almost static or slowly expanding, contrary to more rapidly expanding supershells created by OB associations. We discuss the position of the energy source relative to the symmetry plane of the galaxy: observed arc-like structures can be the ...

  20. A Theory and Typology of Possession in Ob-Yenissei Languages

    Potanina, Olga Sergeevna; Filchenko, Andrey Yurievich

    2015-01-01

    The paper outlines the on-going study of possession in Ob-Yenissei languages. The languages of the project represent the endangered indigenous idioms belonging to diverse language families and united in the study by their areal affiliation with the posited linguistic area delimited by Ob and Yenissei river basins in Western Siberia. The analysis stems from extended original and legacy fieldwork data, and addresses the key morphosyntactic and semantic features of possession within a contempora...

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

    Ekularn Dhavarudha; Chalie Charoenlarpnopparut; Suwan Runggeratigul

    2011-01-01

    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 ...

  2. Kolesarjenje na območju Mestne občine Ptuj

    Cajnko, Uroš

    2012-01-01

    Diplomsko delo obravnava kolesarjenje v Mestni občini Ptuj. Najprej so v uvodnem poglavju predstavljene prednosti kolesarjenja s poudarkom na okoljskem vidiku. V nadaljevanju je predstavljen kolesarski promet v Republiki Sloveniji ter njegova navezava na kolesarske poti v Mestni občini Ptuj. Predstavljene so tudi smernice razvoja kolesarskega omrežja. Prav tako so predstavljene najnovejše ureditve kolesarskega prometa iz tujine, njihovi izvedeni ukrepi in predstavljeni rezultati, na podlagi k...

  3. Evaulation of B{sub 4}C as an ablator material for NIF capsules. Revision 1

    Burnham, A.K.; Alford, C.S.; Makowiecki, D.M.; Dittrich, T.R.; Wallace, R.J.; Honea, E.C.; King, C.M. [Lawrence Livermore National Lab., CA (United States); Steinman, D. [General Atomics, San Diego, CA (United States)

    1997-03-26

    Boron carbide (B{sub 4}C) is examined as a potential fuel container and ablator for implosion capsules on the National Ignition Facility (NIF). A capsule of pure B{sub 4}C encasing a layer of solid DT implodes stably and ignites with anticipated NIF x-ray drives, producing 18 MJ of energy. Thin films of B{sub 4}C were found to be resistant to oxidation and modestly transmitting in the infrared (IR), possibly enabling IR fuel characterization and enhancement for thin permeation barriers but not for full-thickness capsules. Polystyrene mandrels 0.5 mm in diameter were successfully coated with 0.15-2.0 micrometers of B{sub 4}C. Thickness estimated from optical density agreed well with those measured by scanning electron microscopy (SEM). The B{sub 4}C microstructure was columnar but finer than for Be made at the same conditions. B{sub 4}C is a very strong material, with a fiber tensile strength capable of holding NIF fill pressures at room temperature, but it is also very brittle, and microscopic flaws or grain structure may limit the noncryogenic fill pressure. Argon (Ar) permeation rates were measured for a few capsules that had been further coated with 5 micrometers of plasma polymer. The B{sub 4}C coatings tended to crack under tensile load. Some shells filled more slowly than they leaked, suggesting that the cracks open and close under opposite pressure loading. As observed earlier for Ti coatings, 0.15-micrometer layers of B{sub 4}C had better gas retention properties than 2-micrometer layers, possibly because of fewer cracks. Permeation and fill strength issues for capsules with a full ablator thickness of B{sub 4}C are unresolved. 21 refs., 6 figs.

  4. CHMP4C Disruption Sensitizes the Human Lung Cancer Cells to Irradiation

    Kang Li

    2015-12-01

    Full Text Available Human lung cancer is highly invasive and the most malignant among human tumors. Adenocarcinoma as a specific type of non-small cell lung cancer occurs with high frequency and is also highly resistant to radiation therapy. Thus, how to avoid radiation resistance and improve radiotherapy effectiveness is a crucial question. In the present study, human lung cancer A549 and H1299 cells were irradiated using γ-rays from a Co60 irradiator. Protein expression was detected by Western blotting. Cell cycle and apoptosis were measured by flow cytometry. Surviving fraction was determined by colony formation assay. γH2AX and 53BP1 foci formation were examined by fluorescence microscopy. In the results, we show that CHMP4C, a subunit of Endosomal sorting complex-III (ESCRT-III, is involved in radiation-induced cellular response. Radiation-induced Aurora B expression enhances CHMP4C phosphorylation in non-small cell lung cancer (NSCLC cells, maintaining cell cycle check-point and cellular viability as well as resisting apoptosis. CHMP4C depletion enhances cellular sensitivity to radiation, delays S-phase of cell cycle and reduces ionizing radiation (IR-induced γH2AX foci formation. We found that Aurora B targets CHMP4C and inhibition of Aurora B exhibits similar effects with silencing of CHMP4C in radioresistance. We also confirm that CHMP4C phosphorylation is elevated after IR both in p53-positive and-negative cells, indicating that the close correlation between CHMP4C and Aurora B signaling pathway in mediating radiation resistance is not p53 dependent. Together, our work establishes a new function of CHMP4C in radiation resistance, which will offer a potential strategy for non-small cell lung cancer by disrupting CHMP4C.

  5. CHMP4C Disruption Sensitizes the Human Lung Cancer Cells to Irradiation.

    Li, Kang; Liu, Jianxiang; Tian, Mei; Gao, Gang; Qi, Xuesong; Pan, Yan; Ruan, Jianlei; Liu, Chunxu; Su, Xu

    2016-01-01

    Human lung cancer is highly invasive and the most malignant among human tumors. Adenocarcinoma as a specific type of non-small cell lung cancer occurs with high frequency and is also highly resistant to radiation therapy. Thus, how to avoid radiation resistance and improve radiotherapy effectiveness is a crucial question. In the present study, human lung cancer A549 and H1299 cells were irradiated using γ-rays from a Co60 irradiator. Protein expression was detected by Western blotting. Cell cycle and apoptosis were measured by flow cytometry. Surviving fraction was determined by colony formation assay. γH2AX and 53BP1 foci formation were examined by fluorescence microscopy. In the results, we show that CHMP4C, a subunit of Endosomal sorting complex-III (ESCRT-III), is involved in radiation-induced cellular response. Radiation-induced Aurora B expression enhances CHMP4C phosphorylation in non-small cell lung cancer (NSCLC) cells, maintaining cell cycle check-point and cellular viability as well as resisting apoptosis. CHMP4C depletion enhances cellular sensitivity to radiation, delays S-phase of cell cycle and reduces ionizing radiation (IR)-induced γH2AX foci formation. We found that Aurora B targets CHMP4C and inhibition of Aurora B exhibits similar effects with silencing of CHMP4C in radioresistance. We also confirm that CHMP4C phosphorylation is elevated after IR both in p53-positive and-negative cells, indicating that the close correlation between CHMP4C and Aurora B signaling pathway in mediating radiation resistance is not p53 dependent. Together, our work establishes a new function of CHMP4C in radiation resistance, which will offer a potential strategy for non-small cell lung cancer by disrupting CHMP4C. PMID:26712741

  6. 胆汁酸核受体激动剂对瘦素及OB-Rb的影响%Effects of FXR agonist on leptin and OB-Rb

    辛小敏; 张珊珊; 钟慕晓; 杨公利; 彭瑶; 朱薇; 张亚历

    2014-01-01

    目的:观察胆汁酸核受体激动剂GW4064对3T3-L1前脂肪细胞分化过程中瘦素及长型瘦素受体(OB-Rb)和对HepG2细胞 OB-Rb 的影响。方法:用 GW4064干预3T3-L1前脂肪细胞的分化过程,采用荧光real-time PCR 法检测分化过程中第0、2、4、6、8天瘦素及OB-Rb mRNA 相对表达量及ELISA 法检测瘦素分泌情况,同时,用 GW4064干预饥饿后的 HepG2细胞0、12、24、48 h 后,荧光 real-time PCR 法检测 OB-Rb mRNA 相对表达量。结果:GW4064干预后,3T3-L1前脂肪细胞中瘦素 mRNA 相对表达量较对照组明显上升,瘦素蛋白分泌情况与其 mRNA 表达相似,差异均有统计学意义(均 P<0.05),而 OB-Rb mRNA 表达无明显改变(P>0.05);同时,HepG2细胞的OB-Rb mRNA 在干预后表达明显增加,差异有统计学意义(P<0.001)。结论:GW4064可上调脂肪细胞瘦素和HepG2细胞OB-Rb 的表达,目前瘦素在非酒精性脂肪性肝病中的作用及机制尚不明确,而 OB-Rb 的低表达则与非酒精性脂肪性肝病中的瘦素抵抗相关,因此,我们推测胆汁酸核受体激动剂可通过提高肝脏OB-Rb 的表达改善瘦素抵抗,从而达到治疗非酒精性脂肪性肝病的目的。%Objective To investigate the effects of GW4064,one FXR agonist,on the leptin and OB-Rb during the differentiation of 3T3-L1 preadipocytes and on the OB-Rb in the HepG2 cells. Methods The mRNA relative expression of leptin , OB-Rb and the protein of leptin on the day of 0 , 2 , 4 , 6 , 8 during the differentiation of 3T3-L1 preadipocytes after interfered with GW4064 were detected by fluorescent real-time PCR and ELISA , respectively. Meanwhile , the mRNA relative expression of OB-Rb of HepG2 cells after treated with GW4064 0 h , 12 h,24 h,48 h were also examined. Results The mRNA relative expression of leptin in the 3T3-L1 preadipocytes and OB-Rb in the HepG2 cells after treated with GW4064 were significantly

  7. RNA-Seq-basierte Isolierung des Resistenzgens Bs4C aus Paprika

    Strauß, Tina

    2015-01-01

    Das Paprika Resistenzgen Bs4C aus Capsicum pubescens vermittelt Resistenz gegenüber Xanthomonas campestris pv. vesicatoria (Xcv)-Stämmen, die den (transcription activator-like) TAL-Effektor AvrBs4 exprimieren. Vorangegangene Arbeiten ließen vermuten, dass AvrBs4 die Expression von Bs4C transkriptionell induziert. In einem “proof of principle”-Experiment, wurde Bs4C unter Verwendung eines RNA-Seq-basierten Ansatzes isoliert. Unter 68 differentiell AvrBs4-induzierten Paprikagenen war jedoch nur...

  8. Al/ B4C Composites with 5 and 10 wt% Reinforcement Content Prepared by Powder Metallurgy

    The preparation, physical and mechanical properties of Al/ B4C composites with 5 and 10 wt.% reinforcement content were investigated. In order to obtain the feedstock with a low powder loading, B4C mixtures containing fine powders were investigated to obtain the optimal particle packing. The experimental results indicated that the fine containing 5 and 10 wt.% particles are able to prepare the feedstock with a good flowability. The composites fabricated by powder metallurgy have low densities and homogeneous microstructures. Additionally there is no interface reaction observed between the reinforcement and matrix by XRD analysis. The hardness of Al/ B4C composites prepared by powder metallurgy was high. (Author)

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

    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. PMID:25866307

  10. Generation of tritiated methane using a CuO-Al4C3 bed

    With the supply of a constant flow rate of hydrogen with a constant tritium concentration to a CuO-Al4C3 bed at 573 K, methane with a constant radioactivity was generated at a high conversion ratio. Although tritiated methane was conventionally generated using a set of tritiated water vapor bubbler and an Al4C3 bed, its tritium radioactivity was limited by the saturated water vapor pressure and was dropped by a large decrease in density when water was vaporized. The present CuO-Al4C3 bed can substantially eliminate its limit because of the successive conversion from hydrogen to methane using a CuO-Al4C3 bed heated to 573 K. The difference in output between the ionization chamber and the gas chromatography was discussed based on the complete-mixing series-tank model. (author)

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

    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.

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

    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

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

    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) after-school seminar…

  14. Study of influence content of TiB2 by reaction in situ B4C and TiC in mechanical properties on B4C ceramics

    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/cm3) gives in the final product a weight approximately 30% lower than armor made of alumina (3.96 g/cm3). (author)

  15. Effects of temperature variation on LixFePO4/C (0

    肖政伟; 张英杰; 胡国荣

    2015-01-01

    LiFePO4/C was prepared via solid state reaction and characterized with X-ray powder diffraction and charge–discharge test. As-prepared LiFePO4/C has a triphylite structure and exhibits an excellent rate capability and capacity retention. Electrochemical impedance spectroscopy (EIS) was applied to investigate LixFePO4/C (04/C is deeply delithiated at a relatively high temperature. EIS examination indicates that a temperature rise leads to a better reversibility, lower charge transfer resistance, higher exchange current densityJ0 and greater Li+ ion diffusion coefficient for the LixFePO4/C electrode process. The Li+ ion concentration in LixFePO4/C is potential to impact the Li+ ion diffusion coefficient, and a decrease in the former results in an increase in the latter.

  16. A possible OB protostar associated with the molecular outflow in G34.4

    Bronfman, L.; May, J.; Nuernberger, D.; Shepherd, D.

    1999-10-01

    The most conspicuous massive molecular outflow candidate identified in our CS(2-1) survey of UC HII regions (Bronfman et al 1996) is G34.4 (IRAS 18507+0121) in the I Galactic quadrant. At a distance of 3.8 kpc, it is near (about 11') the very bright HII region G34.3 (Carral & Welch 1992), embedded in the same GMC with a VLSR of 57 km/s. The CS velocity profile obtained with SEST shows very broad wings, about 25 km/s wide at the 0.1 K level, indicating strong outflow activity. Near infrared images of the field, 90'' in size (0.35'' per pixel), obtained with the du Pont 100'' Telescope at Las Campanas, show a remarkably reddenned source visible only in the K' filter, elongated in shape, about 15'' in extent. We have recently observed the G34.4 region, using the OVRO array, in the 3 mm continuum band and in the H13CO+ line, at a resolution of 5''. Most of the H13CO+ flux (33.64 Jy) comes from two strong cores; while one of these cores is closely associated with the ! NIR source, the other one is associated with a single, unresolved continuum source that has a total flux of 56.8 mJy. The mass of gas and dust in this second, possibly "star-less" core is estimated from the millimeter continuum to be approximately 355 MSun, consistent with the presence of a massive, embedded OB protostar. Bronfman, L., May, J., & Nyman, L. 1996, A&AS 115, 81 Carral & Welch 1992, ApJ 385, 244

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

    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.

  18. Non-thermal radio emission from colliding-wind binaries: modelling Cyg OB2 No. 8A and No. 9

    Volpi, Delia; Blomme, Ronny; De Becker, Michael; Rauw, Gregor

    2010-01-01

    Some OB stars show variable non-thermal radio emission. The non-thermal emission is due to synchrotron radiation that is emitted by electrons accelerated to high energies. The electron acceleration occurs at strong shocks created by the collision of radiatively-driven stellar winds in binary systems. Here we present results of our modelling of two colliding wind systems: Cyg OB2 No. 8A and Cyg OB2 No. 9.

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

    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.

  20. Spitzer observations of the Orion OB1 association: disk census in the low mass stars

    Hernandez, Jesus; Briceño, C; Hartmann, L; Vivas, A K; Muzerolle, J; Downes, J; Allen, L; Gutermuth, R

    2007-01-01

    We present new Spitzer Space Telescope observations of two fields in the Orion OB1 association. We report here IRAC/MIPS observations for 115 confirmed members and 41 photometric candidates of the ~10 Myr 25 Orionis aggregate in the OB1a subassociation, and 106 confirmed members and 65 photometric candidates of the 5 Myr region located in the OB1b subassociation. The 25 Orionis aggregate shows a disk frequency of 6% while the field in the OB1b subassociation shows a disk frequency of 13%. Combining IRAC, MIPS and 2MASS photometry we place stars bearing disks in several classes: stars with optically thick disks (class II systems), stars with an inner transitional disks (transitional disk candidates) and stars with "evolved disks"; the last exhibit smaller IRAC/MIPS excesses than class II systems. In all, we identify 1 transitional disk candidate in the 25 Orionis aggregate and 3 in the OB1b field; this represents ~10% of the disk bearing stars, indicating that the transitional disk phase can be relatively fast...

  1. Leptin promotes proliferation and metastasis of human gallbladder cancer through OB-Rb leptin receptor.

    Zou, Hao; Liu, Yunxia; Wei, Dong; Wang, Tao; Wang, Kun; Huang, Songquan; Liu, Lixin; Li, Yuehua; Ge, Jiayun; Li, Xiao; Zhu, Hong; Wang, Lianmin; Zhao, Songling; Zhang, Xiaowen; Wang, Lin

    2016-07-01

    Emerging evidence has shown that leptin, an adipocyte-derived cytokine that is closely associated with obesity, play a significant role in carcinogenesis and tumorigenesis. However, its impact on gallbladder cancer (GBC) remains unclear. In this study, we firstly found that leptin and its functional receptor OB-Rb were significantly co-expressed in human GBC tissues and cell lines, the content of which were higher than those in normal human gallbladder tissues. Treatment with leptin promoted the proliferation, migration and invasion of GBC cells, which were attenuated by OB-Rb shRNA. Blocking in the G2/M period of cell cycle, increasing of MMP3 and MMP9, increasing of VEGF-C/D, activation of SOCS3/JAK2/p-STAT3 pathway was demonstrated after treatment with leptin. All of these positive responses were attenuated by OB-Rb receptor shRNA. Taken together, our findings suggest that leptin promoted the proliferation, migration and invasion of GBC cells by increasing OB-Rb expression through the SOCS3/JAK2/p-STAT3 signal pathway. Targeting the leptin/OB-Rb axis could be an attractive therapeutic strategy for treatment of GBC. PMID:27211817

  2. Predlog umestitve gorsko-kolesarskih poti v Občini Litija in Šmartno pri Litiji

    Elsner, Tanja

    2015-01-01

    V diplomskem delu smo podali predloge prostorske umestitve gorsko-kolesarskih poti na območju občine Litija in Šmartno pri Litiji. Občini sta hriboviti, saj sta obdani z gozdovi, njun teren je zanimiv in razgiban. Prav zaradi tega se je vse več ljudi začelo ukvarjati z gorskim kolesarstvom. Občini imata bogato kulturno in naravno dediščino vendar vlagata premalo truda v boljšo turistično prepoznavnost, turizem na tem območju je slabo razvit. Zaradi naravnih danosti občin in zaradi...

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

    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

  4. Synthesis and characterization of Fe 3 O 4 @C@Ag nanocomposites and their antibacterial performance

    Xia, Haiqing; Cui, Bin; Zhou, Junhong; Zhang, Lulu; Zhang, Ji; Guo, Xiaohui; Guo, Huilin

    2011-09-01

    We synthesized Fe 3O 4@C@Ag nanocomposites through a combination of solvothermal, hydrothermal, and chemical redox reactions. Characterization of the resulting samples by X-ray diffraction, Fourier-transform infrared spectroscopy, field-emission scanning and transmission electron microscopy, and magnetic measurement is reported. Compared to Fe 3O 4@Ag nanocomposites, the Fe 3O 4@C@Ag nanocomposites showed enhanced antibacterial activity. The Fe 3O 4@C@Ag nanocomposites were able to almost entirely prevent growth of Escherichia coli when the concentration of Ag nanoparticles was 10 μg/mL. Antibacterial activity of the Fe 3O 4@C@Ag nanocomposites was maintained for more than 40 h at 37 °C. The intermediate carbon layer not only protects magnetic core, but also improves the dispersion and antibacterial activity of the silver nanoparticles. The magnetic core can be used to control the specific location of the antibacterial agent (via external magnetic field) and to recycle the residual silver nanoparticles. The Fe 3O 4@C@Ag nanocomposites will have potential uses in many fields as catalysts, absorbents, and bifunctional magnetic-optical materials.

  5. Vestibular impairment in Charcot-Marie-Tooth disease type 4C.

    Pérez-Garrigues, Herminio; Sivera, Rafael; Vílchez, Juan Jesús; Espinós, Carmen; Palau, Francesc; Sevilla, Teresa

    2014-07-01

    Charcot-Marie-Tooth disease type 4C (CMT4C) is a hereditary neuropathy with prominent unsteadiness. The objective of the current study is to determine whether the imbalance in CMT4C is caused only by reduced proprioceptive input or if vestibular nerve involvement is an additional factor. We selected 10 CMT4C patients and 10 age-matched and sex-matched controls. We performed a comprehensive evaluation of the vestibular system, including video Head Impulse Test, bithermal caloric test, galvanic stimulation test and skull vibration-induced nystagmus test. None of the patients experienced dizziness, spontaneous or gaze-evoked nystagmus, but all had significant vestibular impairment when tested when compared to controls. Seven had completely unexcitable vestibular systems and abnormal vestibuloocular reflex. There was no correlation between the degree of vestibulopathy and age or clinical severity. Significant vestibular impairment is a consistent finding in CMT4C and is present early in disease evolution. The profound imbalance that is so disabling in these patients may result from a combination of proprioceptive loss and vestibular neuropathy, and this would modify the recommended rehabilitation strategies. PMID:24614092

  6. Interlayer growth in Mo/B4C multilayered structures upon thermal annealing

    Both multilayer period thickness expansion and compaction were observed in Mo/B4C multilayers upon annealing, and the physical causes for this were explored in detail. Using in situ time-dependent grazing incidence X-ray reflectometry, period changes down to picometer-scale were resolved. It was shown that the changes depend on the thickness of the B4C layers, annealing temperature, and annealing time. Although strong stress relaxation during annealing was observed, it was excluded as a cause for period expansion. Auger electron spectroscopy and wide angle X-ray diffraction measurements revealed the growth of interlayers, with associated period changes influenced by the supply of B and C atoms to the growing compound interlayers. For multilayers with a Mo thickness of 3 nm, two regimes were recognized, depending on the deposited B4C thickness: in multilayers with B4C ≤ 1.5 nm, the supply of additional Mo into the already formed MoBxCy interlayer was dominant and led to densification, resulting in period compaction. For multilayers with B4C ≥ 2 nm, the B and C enrichment of interlayers formed low density compounds and yielded period expansion.

  7. Wetting of B4C, TiC and graphite substrates by molten Mg

    Highlights: → The wettability of TiC, B4C and C by molten Mg was determined using an improved sessile drop method. → A new method to evaluate the wetting behavior coupled with evaporation and reaction was proposed. → The bonding characteristics in the Mg/B4C, Mg/TiC and Mg/graphite systems were evaluated. - Abstract: The isotherm wetting of B4C, 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 B4C 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/B4C and Mg/TiC systems is presumably mainly chemical while that in the Mg/graphite system is physical.

  8. Hierarchical system of shells blown by wind of Cyg OB1 stars

    The structure and kinematics of gas-dust complex connected with the Cyg OB1 association and open clusters NGC 6913 and IC 4996 have been investigated. the optical and radio brightness distribution along with the radial velocities field provided by the available observations in Hα, CO, HI and recombination radio lines is analyzed. Several new ring nebulae and/or cavities in CO - distribution around the WR and Of stars are distinguished. An hierarchial system of ''inclosed'' shells is revealed: the common shell around Cyg OB1 consists of two components - the shells around NGC 6913 and IC 4996 with small-size WR and Of ring nebulae inside. Interferometric Hα observations of the region provided the common shell expansion velocity Vexp < or approx. 15 km/s. The origin of the multi-stellar structure of the ISM around Cyg OB1 is discussed

  9. $\\gamma$ Ray Bursts versus OB Associations do they trigger star formation?

    Efremov, Yu N; Palous, J; Efremov, Yu.N.

    1999-01-01

    We discuss differences in shapes, expansion velocities and fragmentation times of structures created by an energy deposition from a single Gamma Ray Burst (GRB) or an OB association to the ISM. After the initial inflation, supershells produced by GRBs are almost static or slowly expanding, contrary to more rapidly expanding supershells created by OB associations. We discuss the position of the energy source relative to the symmetry plane of the galaxy: observed arc-like structures can be the most dense parts of structures formed by an expansion from a source above or below the galactic plane. Arcs may also form, if the expansion takes place inside a giant HI cloud. We try to reproduce the size, the age and the average distance between OB associations in the Sextant region at the edge of LMC 4.

  10. An X-ray and Infrared Hunt for New Candidate Galactic OB Stars

    Povich, Matthew S.; Alexander, Michael J.; Busk, Heather; Hanes, Richard J.; Feigelson, Eric; McSwain, M. Virginia; Townsley, Leisa K.

    2016-01-01

    Most young, massive OB stars produce X-ray emission through a variety of wind-driven shock processes, and individual massive stars are detectable out to several kpc distances in the Galactic plane using high-resolution imaging observations from the Chandra X-ray Observatory. We have developed a technique to identify known and new candidate OB stars by fitting model stellar atmospheres to the broadband infrared spectral energy distributions of X-ray-identified stars. Using this technique, we identified 94 candidate O- and early B-type stars in the Carina Nebula and an additional 98 candidates in 11 other Galactic Massive Star-Forming Regions. Visible-light and near-infrared follow-up spectroscopy of these candidates is ongoing, and initial results indicate that a majority of candidate massive stars will be spectroscopically confirmed as OB stars.

  11. Identification of current attacks and their counter measures in Optical Burst Switched (OBS network

    Siddharth Singh Chouhan

    2012-03-01

    Full Text Available As day by day application grows internet requires large amount of bandwidth. Optical Burst Switching (OBS is the next generation optical Internet with IP over WDM as the core architecture. It can achieve a balance between Optical Circuit Switching (OCS and Optical Packet Switching (OPS. Optical network supports huge bandwidth and transmits data at an average rate of 50Tb/s. But we need to exploit the fiber’s huge bandwidth through WDM which is the current favorite multiplexing technology in Optical communication networks. OBS is a trusted mechanism used for optical switching. Optical burst switching has been positioned as a viable means of implementing optical communication efficiently. This review paper identifies potential threats to security in OBS networks. Solutions in each category are examined, and research directions are presented.

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

    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)

  13. The design, fabrication and properties of B4C/Al neutron absorbers

    Neutron absorber is used for the criticality safety during the storage or transportation of spent nuclear fuel. In this work, the metal matrix composite with good mechanical property and thermal neutron absorbing ability was investigated based on B4C/Al neutron radiation shielding material. The composition ratio for B4C/Al composite was firstly designed and the dependence of the neutron transmission on the thickness of the material was calculated. By vacuum hot-pressing technique at a low temperature, the neutron absorbers with high concentration of B4C were fabricated. Furthermore, the corresponding microstructure, physical, mechanical and corrosion properties as well as fracture surface were analyzed, proving that the developed composites can shield the neutron radiation as effectively as cadmium materials

  14. Neutron absorption of Al-Si-Mg-B4C composite

    Al-Si-Mg-B4C composites containing 2-8 wt% of B4C 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/Be241. The result indicated that higher B4C 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

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

    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.

  16. Immunoneutralization of endogenous glucagon reduces hepatic glucose output and improves long-term glycemic control in diabetic ob/ob mice

    Sørensen, Heidi; Brand, Christian L; Neschen, Susanne;

    2006-01-01

    synthesis. Glucagon mAb treatment for 5 days lowered plasma glucose and triglyceride levels, whereas 14 days of glucagon mAb treatment reduced A1C. In conclusion, acute and subchronic neutralization of endogenous glucagon improves glycemic control, thus supporting the contention that glucagon antagonism may......In type 2 diabetes, glucagon levels are elevated in relation to the prevailing insulin and glucose levels. The relative hyperglucagonemia is linked to increased hepatic glucose output (HGO) and hyperglycemia. Antagonizing the effects of glucagon is therefore considered an attractive target for...... treatment of type 2 diabetes. In the current study, effects of eliminating glucagon signaling with a glucagon monoclonal antibody (mAb) were investigated in the diabetic ob/ob mouse. Acute effects of inhibiting glucagon action were studied by an oral glucose tolerance test (OGTT) and by measurement of HGO...

  17. Stability of 10B4C thin films under neutron radiation

    Thin films of 10B4C have shown to be very suitable as neutron-converting material in the next generation of neutron detectors, replacing the previous predominantly used 3He. In this contribution we show under realistic conditions that 10B4C films are not damaged by the neutron irradiation and interactions, which they will be exposed to under many years in a neutron detector. 1 μm thick 10B4C thin films were deposited onto Al or Si substrates using dc magnetron sputtering. As-deposited films were exposed to a cold neutron beam with fluences of up to 1.1×1014 cm−2 and a mean wavelength of 6.9 Å. Both irradiated and as-deposited reference samples were characterized with time-of-flight elastic recoil detection analysis, scanning electron microscopy, transmission electron microscopy, X-ray photoemission spectroscopy, and X-ray diffraction. We show that only 1.8 ppm of the 10B atoms were consumed and that the film composition does not change by the neutron interaction within the measurement accuracy. The irradiation does not deteriorate the film adhesion and there is no indication that it results in increased residual stress values of the as-deposited films of 0.095 GPa. From what is visible with the naked eye and down to atomic level studies, no change from the irradiation could be found using the above-mentioned characterization techniques. - Highlights: • 10B4C films are not damaged by radiation during many years in a neutron detector. • 1 μm 10B4C thin films were exposed to a 1.1×1014 cm−2 cold neutron beam. • Only 1.8 ppm of the 10B atoms were consumed. • No change in film composition, adhesion or residual stress. • 10B4C based neutron detectors are very suitable replacements for 3He detectors

  18. Interfacial reaction mechanism between matrix and reinforcement in B4C/6061Al composites

    The interfacial reaction mechanism in B4C/6061Al composites, fabricated by the powder metallurgy technique at 560 and 620 °C with various holding times, was subjected to detailed investigations using optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and hardness tests. Results showed that complicated interfacial reactions occurred in the B4C/6061Al composites, forming Al3BC, MgAl2O4, MgB7, Mg0.78Al0.75B14, AlB12C2 and Al4SiC4 as the main products, which clearly deteriorated the age-hardening ability of the composites. The interfacial reactions involving Mg and Si could be divided into two series. The oxidation of Mg occurred at both 560 and 620 °C, whereas other reactions only occurred at 620 °C. The existence of the liquid phase at 620 °C activated the reaction between Al and B4C, leading to the generation of free B, and subsequent reactions involving B and Mg occurred. After the reactions involving B and Mg was completed, the reaction involving Al, Si and C took place. It was determined that the reactions involving B and Mg rather than the oxidation of Mg or the reaction involving Si were the main reasons for the consumption of Mg and the deterioration of age-hardening ability of the B4C/6061Al composites at 620 °C. - Highlights: • Complicated interfacial reactions occurred in B4C/6061Al composites. • Reactions involving Mg and Si were divided into oxidation of Mg and other reactions. • Al/B4C reaction produced free B and then activated B/Mg reactions. • B/Mg reactions rather than Mg oxidation were main reasons for Mg consumption. • Interfacial reactions definitely deteriorate age-hardening ability of composites

  19. Note on thermodynamic instability of M4C3-type carbides of gallium group metals

    The paper deals with thermodynamic stability of hypothetical solid binary M4C3 carbides of gallium, indium and thallium. Heats of formation whose contribution to the stability of these compounds is dominant, were estimated by two independent methods: semiempirical theory of Miedema and empirical trends in the heats of formation of nitrides and carbides of Group III elements. Entropies were calculated with the use of the Cantor equation. The estimated values suggest that M4C3 carbides of gallium, indium and thallium are thermodynamically unstable with regard to their decomposition of elements. (Author)

  20. Chemical interactions of B4C pellets with Zr1%Nb and stainless steels

    Chemical interactions between B4C absorber material and X18H10T stainless steel absorber cladding of WWER type nuclear reactor, together with those between B4C and Zr1%Nb guide tube were investigated in the temperature range of 800-1200 and 1200-1600 deg C, respectively. After annealing, the specimens where exposed to metallograhical testing. The results show that the reaction obeys parabolic law, and the growth rate of the reaction layers can be described by an Arrhenius correlation. (author). 5 refs., 20 figs., 3 tabs

  1. Hardness and wear resistance of reaction bonded SiC-B4C composite

    Hardness and wear resistant characteristics of reaction-bonded silicon carbides with boron carbide additions are evaluated relative to those of reaction bonded silicon carbide (RBSC). The reaction-bonded SiC-B4C composites exhibit a distinctive improvement of hardness and wear resistance, indicative of high resistance against wear environment. Removal rates for the wear tests are decisively reduced by the addition of boron carbide in the composites. Controlling the amount of carbon content in the starting composition more enhances the hardness of the reaction-bonded composites. Implications concerning the partial decomposition of B4C during reaction process are considered. (orig.)

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

    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. PMID:26492472

  3. Genistein supplementation prevents weight gain but promotes oxidative stress and inflammation in the vasculature of female obese ob/ob mice.

    Simperova, Anna; Al-Nakkash, Layla; Faust, James J; Sweazea, Karen L

    2016-08-01

    Obesity, a state of chronic low-grade inflammation, is strongly associated with the development of hypertension and diabetes. Superoxide, a free radical elevated in obese individuals, promotes hypertension through scavenging the endogenous vasodilator nitric oxide. The hypothesis was a genistein-enriched diet would promote weight loss and reduce oxidative stress and inflammation in the vasculature of intact female ob/ob mice. Aortas and mesenteric arteries were isolated from female ob/ob mice fed genistein-free (0mg genistein/kg diet; n=6), standard chow (200-300mg genistein/kg diet; n=11) or genistein-enriched (600mg genistein/kg diet; n=9) diets for 4weeks. Sections of isolated vessels were labeled with the superoxide indicator dihydroethidium and fluorescence was measured by confocal microscopy. Protein expression of the inflammatory marker inducible nitric oxide synthase (iNOS) was measured in the perivascular adipose tissue (PVAT) surrounding each vessel and plasma concentrations of superoxide dismutase (SOD) were quantified. Genistein-enriched diet promoted less weight gain compared to animals fed standard chow (P=.008). Standard chow promoted increased superoxide in the aorta (P=.030) and mesenteric arteries (P=.024) compared to a diet devoid of genistein. At all tested concentrations, genistein significantly increased iNOS expression in mesenteric artery PVAT (vs. standard chow, P<.001; vs. genistein-enriched, P=.002) and tended to increase iNOS within the aortic PVAT (standard chow, P=.075) compared to the genistein-free group. Plasma SOD activity was significantly downregulated in genistein-enriched animals as compared to those fed a genistein-free diet (P=.028). In summary, although genistein prevents weight gain, it promotes vascular oxidative stress and inflammation in obese ovarian-intact female mice. PMID:27440533

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

    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.

  5. Organizacijska kultura občinskega redarstva : diplomsko delo univerzitetnega študija

    Rudnik, Kaja

    2013-01-01

    Organizacijska kultura je skupek vrednot, norm, prepričanj, ki so sprejete v organizaciji in prikazujejo, kako naj se ljudje znotraj nje vedejo, komunicirajo in kakšne delovne odnose naj razvijejo. Organizacijske kulture se med seboj razlikujejo, saj ima vsaka organizacija svoja pravila oblačenja, rituale, naloge, formalna pravila, procedure itd. Namen diplomske naloge je bil predstaviti organizacijsko kulturo občinskega redarstva. Preučevanje je potekalo v dveh slovenskih občinah, A in B...

  6. Evaluation of metal content in perch of the Ob River basin

    Osipova, Nina Aleksandrovna; Stepanova, Kristina Dmitrievna; Matveenko, Irina Alekseevna

    2015-01-01

    The geochemical features of river perch in the River Ob basin have been studied (the upper and middle reaches of the Ob River and the lower reach of the Tom River). The contents of Ag, Bi, Cd, Co, Cr, Cu, Fe, Mn, Mo, Ni, Pb, Sn, W, Zn, Hg in perch's soft tissue are defined by the methods of ICP AES and stripping voltammetry, that of mercury in bones - by the atomic absorption method using mercury analyzer РА-915+. The distribution series of metal absolute concentrations in perch's soft tissue...

  7. Large-scale coupled hydrologic and hydraulic modelling of the Ob river in Siberia

    Biancamaria, Sylvain; Bates, Paul; Boone, Aaron; Mognard, Nelly

    2009-01-01

    The Ob river in Western Siberia is one of the largest rivers in the Arctic and has a complex hydrological cycle mainly driven by snow melting in spring and rainfall and evapotranspiration in summer/autumn. The Ob is a source of fresh water for the Arctic Ocean and a change in its regime could affect the ocean thermohaline circulation. Due to the scarcity of in situ measurements in the Arctic and the size of the region, the hydrological modelling of large Arctic rivers is difficult to perform....

  8. Spatially resolved STIS spectra of WR+OB binaries with colliding winds

    Lepine, Sebastien; Wallace, Debra; Shara, Michael M.; Moffat, Anthony F. J.; Niemela, Virpi S.

    2001-01-01

    We present spatially resolved spectra of the visual WR+OB massive binaries WR86, WR146, and WR147, obtained with the Space Telescope Imaging Spectrograph on board the Hubble Space Telescope. The systems are classified as follows: WR86 = WC7 + B0 III, WR146 = WC6 + O8 I-IIf, WR147 = WN8 + O5-7 I-II(f). Both WR146 and WR147 are known to have strong non-thermal radio emission arising in a wind-wind collision shock zone between the WR and OB components. We find that the spectra of their O compani...

  9. Refined crystal structure of cubic skeletov zinc borate Zn4O[B6O12

    Cubic crystals of the Zn4O[B6O12] composition obtained from the ZnO-B2O3-Li2O(Na2O,K2O)-H2O system with the NnO addition are studied in the temperature range of 250-450 deg C and at the pressure of 1000 atm. It is established that stable crystallization zones are characteristic for the above compound. The crystals are colourless and possess luminescent properties. Interplane distances, cubic lattice parameters and interatomic distances in the Zn4O[B6O12] structure are determined

  10. Electrochemical Behavior of Spherical LiFePO4/C Nanomaterial in Aqueous Electrolyte, and Novel Aqueous Rechargeable Lithium Battery with LiFePO4/C anode

    We designed a novel aqueous rechargeable lithium battery with LiFePO4/C (LFP) and LiMn2O4/C (LMO) as the anode and cathode, respectively; then investigated the battery in Li2SO4 aqueous electrolyte. We also studied the electrochemical behavior of LFP in aqueous electrolyte using cyclic voltammetry (CV). The material exhibited excellent electrochemical performance in the aqueous electrolyte, including good oxidation/reduction reversibility and cycling stability; almost no decays were observable after 200CV cycles. The diffusion coefficients of Li ions through the interface between the liquid electrolyte and the solid LiFePO4 in terms of intercalation and deintercalation were 1.22 × 10−14 and 9.97 × 10−15 cm2/s, respectively. The material could be completely intercalated/deintercalated with Li ions in the aqueous electrolyte, indicating the excellent performance of LFP in an aqueous solution. Further, an aqueous rechargeable lithium battery (ARLB), which we fabricated using LFP as the anode and LMO as the cathode, also exhibited quite good performance in aqueous Li2SO4 solution: after 1,000 charge–discharge cycles at 2 C, the capacity loss was less than 30%, indicating that this type of ARLB has excellent cycling stability and may be promising for future research and application

  11. Sources and transport of anthropogenic radionuclides in the Ob River system, Siberia

    Cochran, J. Kirk; Moran, S. Bradley; Fisher, Nicholas S.; Beasley, Thomas M.; Kelley, James M.

    2000-06-01

    The potential sources of anthropogenic radionuclides to the Ob River system of western Siberia include global stratospheric fallout, tropospheric fallout from atomic weapons tests and releases from production and reprocessing facilities. Samples of water, suspended and bottom sediments collected in 1994 and 1995 have been used to characterize the sources and transport of 137Cs, Pu isotopes, 237Np and 129I through the system. For the radionuclides that associate with particles, isotope ratios provide clues to their sources, providing any geochemical fractionation can be taken into account. Activity ratios of 239,240Pu/ 137Cs in suspended sediments are lower than the global fallout ratio in the Irtysh River before its confluence with the Ob, comparable to fallout in the central reach of the Ob, and greater than the fallout values in the lower Ob and in the Taz River. This pattern mirrors the downriver decrease in dissolved organic carbon (DOC) concentrations. Laboratory adsorption experiments with Ob River sediment and water show that Kd values for Am (and presumably other actinides) are depressed by two orders of magnitude in the presence of Ob DOC concentrations, relative to values measured in DOC-free Ob water. Iodine and cesium Kd values show little or no (less than a factor of 2) dependence on DOC. Mixing plots using plutonium isotope ratios (atom ratios) show that Pu in suspended sediments of the Ob is a mixture of stratospheric global fallout at northern latitudes, tropospheric fallout from the former Soviet Union test site at Semipalatinsk and reprocessing of spent fuel at Tomsk-7. Plutonium from Semipalatinsk is evident in the Irtysh River above its confluence with the Tobal. Suspended sediment samples taken in the Ob above its confluence with the Irtysh indicate the presence of Pu derived from the Tomsk-7 reprocessing facilities. A mixing plot constructed using 237Np/ 239Pu vs. 240Pu/ 239Pu shows similar mixtures of stratospheric and tropospheric fallout

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

    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. 29 CFR 4.163 - Section 4(c) of the Act.

    2010-07-01

    ...) Collective bargaining agreement must be applicable to work performed on the predecessor contract. Section 4(c... contract of a wage determination based on the predecessor contractor's collective bargaining agreement... identifiable contract work requirements into new or consolidated contracts, provided that the new...

  14. Preparation of homogeneous B4C ceramics with high toughness by tape casting

    Highlights: ► The homogeneous B4C ceramics are prepared by tape casting and hot pressing. ► Phase, microstructure and mechanical properties of samples were investigated. ► The reasons for the improvement in mechanical properties were discussed. - Abstract: The homogeneous B4C ceramics are successfully prepared through tape casting, laminating and hot pressing. The obtained B4C slurry exhibited a shear thinning behavior. After tape casting, both sides of the green sheets were smooth and homogeneous. After lamination and decomposition treatment developed in argon, hot press sintering of laminated boron carbide was proceed at 2000 °C. The results indicate that the strength and fracture toughness of B4C specimens are 585 MPa and 4.9 MPa m1/2, respectively. The primary fracture mode is an intergranular type. The reasons for the improvement in mechanical properties should lie in the tape casting processing technique and the presence of carbonaceous residues in specimen.

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

    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. (paper)

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

    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.

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

    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.

  18. Hypovalency--a kinetic-energy density description of a 4c-2e bond.

    Jacobsen, Heiko

    2009-06-01

    A bond descriptor based on the kinetic energy density, the localized-orbital locator (LOL), is used to characterize the nature of the chemical bond in electron deficient multi-center bonds. The boranes B(2)H(6), B(4)H(4), B(4)H(10), [B(6)H(6)](2-), and [B(6)H(7)](-) serve as prototypical examples of hypovalent 3c-2e and 4c-2e bonding. The kinetic energy density is derived from a set of Kohn-Sham orbitals obtained from pure density functional calculations (PBE/TZVP), and the topology of LOL is analyzed in terms of (3,-3) attractors (Gamma). The B-B-B and B-H-B 3c-2e, and the B-B-H-B 4c-2e bonding situations are defined by their own characteristic LOL profiles. The presence of one attractor in relation to the three or four atoms that are engaged in electron deficient bonding provides sufficient indication of the type of 3c-2e or 4c-2e bond present. For the 4c-2e bond in [B(6)H(7)](-) the LOL analysis is compared to results from an experimental QTAIM study. PMID:19452076

  19. Gaseous swelling of B4C and UO2 fuel: similarities and differences

    A major factor limiting the resource of control rods (CRs) for WWER-1000 reactors is their radiation damage. Radiation induced embrittlement of the CRs cladding, core swelling and gaseous internal pressure in CRs result in mechanical core-cladding interaction. This work is devoted to the physical analysis of processes that control the structural changes in neutron absorber elements with B4C under irradiation in water reactors. Particularly, the analysis of mechanisms of the helium porosity formation in B4C is undertaken. In view of the deficiency of experimental data on the subject, a fruitful approach to the problem is a comparative analysis of the swelling mechanisms in B4C absorber and UO2 fuel. Using this similarity a phenomenological model of fission gas behavior in boron carbide is proposed. The model predictions for radial profile of 10B burnup under influence of thermal and epithermal neutrons are compared with experimental results. The main results show that despite the external similarity of the process of fission gas accumulation in UO2 and in B4C, phenomenology of gaseous swelling is much different for the fuel and the CR core. The reason for that difference is the distinction of physical conditions in irradiated fuel and CR core

  20. Characterization of Al–Al4C3 nanocomposites produced by mechanical milling

    In this work, a mixture of Al–C–Al4C3 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 Al4C3 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 Al4C3 with during sintering time restricted the excessive growth of the crystallite. • Al4C3 located in the grain boundaries causes brittle fracture observed in compression tests. • There is a correlation between, crystallite size and microstrain values with microhardness

  1. New neutron-shielding material SBR admixed with B4C

    Styrene-Butadiene-Rubber (SBR) admixed with similar quantity of B4C powder has been developed for shielding of thermal neutrons. The material has both high flexibility and good workability. It is successfully used as part of the shielding for a neutron spectrometer. (auth.)

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

    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

  3. 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

    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。

  4. Predicting GAIA's Parallax Distance to the Cygnus OB2 Association with Eclipsing Binaries

    Kiminki, Daniel C.; Kobulnicky, Henry A.; Vargas Álvarez, Carlos A.; Alexander, Michael J.; Lundquist, Michael J.

    2015-10-01

    The Cygnus OB2 Association is one of the nearest and largest collections of massive stars in the Galaxy. Situated at the heart of the “Cygnus X” complex of star-forming regions and molecular clouds, its distance has proven elusive owing to the ambiguous nature of kinematic distances along this ℓ ≃ 80° sightline and the heavy, patchy extinction. In an effort to refine the three-dimensional geometry of key Cygnus X constituents, we have measured distances to four eclipsing double-lined OB-type spectroscopic binaries that are probable members of Cyg OB2. We find distances of 1.33 ± 0.17, 1.32 ± 0.07, 1.44 ± 0.18, and 1.32 ± 0.13 kpc toward MT91 372, MT91 696, CPR2002 A36, and Schulte 3, respectively. We adopt a weighted average distance of 1.33 ± 0.06 kpc. This agrees well with spectrophotometric estimates for the Association as a whole and with parallax measurements of protostellar masers in the surrounding interstellar clouds, thereby linking the ongoing star formation in these clouds with Cyg OB2. We also identify Schulte 3C (O9.5V), a 4″ visual companion to the 4.75 day binary Schulte 3(A+B), as a previously unrecognized Association member.

  5. Uptake and effect of rare earth elements on gene expression in Methylosinus trichosporium OB3b.

    Gu, Wenyu; Farhan Ul Haque, Muhammad; DiSpirito, Alan A; Semrau, Jeremy D

    2016-07-01

    It is well known that Methylosinus trichosporium OB3b has two forms of methane monooxygenase (MMO) responsible for the initial conversion of methane to methanol, a cytoplasmic (soluble) methane monooxygenase and a membrane-associated (particulate) methane monooxygenase, and that copper strongly regulates expression of these alternative forms of MMO. More recently, it has been discovered that M. trichosporium OB3b has multiple types of the methanol dehydrogenase (MeDH), i.e. the Mxa-type MeDH (Mxa-MeDH) and Xox-type MeDH (Xox-MeDH), and the expression of these two forms is regulated by the availability of the rare earth element (REE), cerium. Here, we extend these studies and show that lanthanum, praseodymium, neodymium and samarium also regulate expression of alternative forms of MeDH. The effect of these REEs on MeDH expression, however, was only observed in the absence of copper. Further, a mutant of M. trichosporium OB3b, where the Mxa-MeDH was knocked out, was able to grow in the presence of lanthanum, praseodymium and neodymium, but was not able to grow in the presence of samarium. Collectively, these data suggest that multiple levels of gene regulation by metals exist in M. trichosporium OB3b, but that copper overrides the effect of other metals by an as yet unknown mechanism. PMID:27190151

  6. SPECTROSCOPIC CONFIRMATION OF THE DRAGONFISH ASSOCIATION: THE GALAXY'S MOST LUMINOUS OB ASSOCIATION

    Rahman, Mubdi; Moon, Dae-Sik; Matzner, Christopher D., E-mail: rahman@astro.utoronto.ca [Department of Astronomy and Astrophysics, University of Toronto, 50 St. George Street, Toronto, ON M5S 3H4 (Canada)

    2011-12-20

    Young OB associations with masses greater than 10{sup 4} M{sub Sun} have been inferred to exist in the Galaxy but have largely evaded detection. Recently, a candidate OB association has been identified within the most luminous star-forming complex in the Galaxy, the Dragonfish Nebula. We identify 18 young, massive stars with near-infrared spectroscopy from a sample of 50 members within the candidate OB association, including 15 O-type and 3 luminous blue variables or Wolf-Rayet stars. This number matches the expected yield of massive stars from the candidate association, confirming its existence and ability to power the parent star-forming complex. These results demonstrate the existence of a 10{sup 5} M{sub Sun} OB association, more powerful than any previously known in the Galaxy, comparable in mass only to Westerlund 1. Further, the results also validate the color selection method used to identify the association, adding credence to others discovered in the same way.

  7. The Unit control of an acquisition system for ocean bottom seismometer (OBS)

    Carreras Pons, Normandino; Roset Juan, Francesc Xavier; Shariat Panahi, Shahram; Artero Delgado, Carola; Manuel Lázaro, Antonio; Owen, Tim; Antonijuan Rull, Josefina

    2012-01-01

    In this paper we talk about an acquisition system for seismic data. The Ocean Bottom Seismometer (OBS) is equipment designed to obtain the seismic marine data from the seabed. The main part of this paper is based in an application which controls the acquisition data of four measurement channels. This system has been tested in lab, getting the corresponding results.

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

    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

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

    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

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

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

    1996-01-01

    /EBP alpha expression vector into 3T3-L1 cells with a series of 5' truncated ob gene promoter constructs activated reporter gene expression with all constructs containing the proximal C/EBP binding site (nucleotides -55 to -47). Mutation of this site blocked transactivation by C/EBP alpha. Taken together...

  11. Analytical model of a burst assembly algorithm for the VBR in the OBS networks

    This paper presents a proposed analytical model for the number of bursts aggregated in a period of time in OBS networks. The model considers the case of VBR traffic with two different sending rates, which are SCR and PCR. The model is validated using extensive simulations. Where results from simulations are in total agreement with the results obtained by the proposed model. (author)

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

    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. PMID:26613539

  13. Epidémie d’obésité : comment lutter

    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

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

    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.

  15. Photoionization of the diffuse interstellar medium and galactic halo by OB associtations

    Dove, James B.; Shull, J. Michael

    1994-01-01

    Assuming smoothly varying H I distributions in te Galactic disk, we have calculated the geometry of diffuse II regions due to OB associations in the Galactic plane. Near the solar circle, OB associations with a Lyman continuum (Lyc) photon luminosity Psi(sub Lyc) = 3.3 x 10(exp 7) cm(exp -2) s(exp -1), produce H II regions that are density bounded in the vertical direction (H II chimneys) allowing Lyc to escape the gaseous disk and penetrate into the Galactic halo. We provide analytic formulae for the Lyc escape fraction as functions of S(sub 0) O-star catalog of Garmany and a new Lyc stellar stellar Lyc stellar flux calibration, we find a production rate of Lyc photons by OB associations within 2.5 kpc of Psi(sub Lyc) = 3.3 x 10(exp 7) cm(exp -2) s(exp -1). Integrating the fraction of Lyc photons that escape the disk over our adopted luminosity function of OB associations, we estimate that approximately 7% of the ionizing photons, or Phi(sub Lyc) = 2.3 x 10(exp 6) cm(exp -2) s(exp -1), escape each side of the H I disk layer and penetrate the diffuse ionized medium ('Reynolds layer'). This flux is sufficient to explain the potoionization of this, although we have not constructed a model for the observed H-alpha emission and pulsar dispersion measures that is fully consistent with the absorption rate of Lyc in the H II layer. Since our quiescent model does not account for the effects of dynamic chimneys and superbubbles, which should enhance Lyc escape, we conclude the O stars are the probable source of ionizing radiation for the Reynolds layer. For a random distribution of OB associations throughout the disk, the Lyc flux is nearly uniform for heights Z is greater than approximately 0.8 kpc above the midplane.

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

    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.

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

    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.

  18. Interfacial reaction mechanism between matrix and reinforcement in B{sub 4}C/6061Al composites

    Li, Y.Z. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Wang, Q.Z., E-mail: qzwang@imr.ac.cn [Key Laboratory of Nuclear Materials and Safety Assessment, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Wang, W.G.; Xiao, B.L. [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China); Ma, Z.Y., E-mail: zyma@imr.ac.cn [Shenyang National Laboratory for Materials Science, Institute of Metal Research, Chinese Academy of Sciences, 72 Wenhua Road, Shenyang 110016 (China)

    2015-03-15

    The interfacial reaction mechanism in B{sub 4}C/6061Al composites, fabricated by the powder metallurgy technique at 560 and 620 °C with various holding times, was subjected to detailed investigations using optical microscopy, scanning electron microscopy, transmission electron microscopy, X-ray diffraction and hardness tests. Results showed that complicated interfacial reactions occurred in the B{sub 4}C/6061Al composites, forming Al{sub 3}BC, MgAl{sub 2}O{sub 4}, MgB{sub 7}, Mg{sub 0.78}Al{sub 0.75}B{sub 14}, AlB{sub 12}C{sub 2} and Al{sub 4}SiC{sub 4} as the main products, which clearly deteriorated the age-hardening ability of the composites. The interfacial reactions involving Mg and Si could be divided into two series. The oxidation of Mg occurred at both 560 and 620 °C, whereas other reactions only occurred at 620 °C. The existence of the liquid phase at 620 °C activated the reaction between Al and B{sub 4}C, leading to the generation of free B, and subsequent reactions involving B and Mg occurred. After the reactions involving B and Mg was completed, the reaction involving Al, Si and C took place. It was determined that the reactions involving B and Mg rather than the oxidation of Mg or the reaction involving Si were the main reasons for the consumption of Mg and the deterioration of age-hardening ability of the B{sub 4}C/6061Al composites at 620 °C. - Highlights: • Complicated interfacial reactions occurred in B{sub 4}C/6061Al composites. • Reactions involving Mg and Si were divided into oxidation of Mg and other reactions. • Al/B{sub 4}C reaction produced free B and then activated B/Mg reactions. • B/Mg reactions rather than Mg oxidation were main reasons for Mg consumption. • Interfacial reactions definitely deteriorate age-hardening ability of composites.

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

    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.

  20. Chemical compatibility of sodium exposed alloy D9 with B4C

    The control rods in India's first prototype fast breeder reactor (PFBR) would consist of high-density B4C (containing 67% 10B isotope) pellets enclosed in alloy D9 clad tubes. Enriched boron carbide required for control rod applications in PFBR is being produced indigenously by reacting elemental boron with graphite at high temperatures. The gap between the control rod material and the clad is filled with liquid sodium as the pins are of vented type. At the reactor operating temperatures of 773-873 K, the chemical interaction between B4C and D9 clad material surface modified by liquid sodium needs to be investigated and understood. Towards this, out-of-pile accelerated chemical compatibility experiments were carried out and the SEM/EDS, XRD and XPS results of the studies carried out at 973 K for 5000 h are presented in this paper

  1. Radio structures of a complete sample of quasars from the 4C catalog

    Radio observations are reported for 57 quasars. Included are all of the quasars of Schmidt's 1974 complete sample from the 4C catalog. The observations were made with the Green Bank interferometer at 2.7 and 8.1 GHz, with baselines ranging from 300 m to 35 km. Model brightness distributions are presented, consisting of one to four elliptical Gaussian components. Angular sizes range from <0.2 to 77 arcsec. Of 38 well-resolved sources 21 contain a compact central component coincident with the optical object. The quasar 4C32. 69=2349+328 appears to exhibit a jetlike structure connecting the central component to one of the outer lobes

  2. CODEX-B4C experiment. Core degradation test with boron carbide control rod

    The CODEX-B4C bundle test has been successfully performed on 25th May 2001 in the framework of the COLOSS project of the EU 5th FWP. The high temperature degradation of a VVER-1000 type bundle with B4C control rod was investigated with electrically heated fuel rods. The experiment was carried out according to a scenario selected in favour of methane formation. Degradation of control rod and fuel bundle took place at temperatures ∼2000 deg C, cooling down of the bundle was performed in steam atmosphere. The gas composition measurement indicated no methane production during the experiment. High release of aerosols was detected in the high temperature oxidation phase. The on-line measured data are collected into a database and are available for code validation and development. (author)

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

    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.

  4. Corrosion and tribocorrosion behavior of Ti-B4C composite intended for orthopaedic implants.

    Toptan, F; Rego, A; Alves, A C; Guedes, A

    2016-08-01

    Poor wear resistance of titanium is a major concern since relative movements due to the cyclic loads in body environment cause wear between the bone and the implant material leading to detachment of the wear debris and release of metal ions due to the simultaneous action of corrosion and wear, defined as tribocorrosion. In order to increase the tribocorrosion resistance, Grade 2 Ti matrix 24vol% B4C particle reinforced composites were processed by hot pressing. Corrosion behaviour was investigated by electrochemical impedance spectroscopy and potentiodynamic polarization in 9g/L NaCl solution at body temperature. Tribocorrosion tests were performed under open circuit potential, as well as under potentiodynamic polarization using a reciprocating ball-on-plate tribometer. Results suggested that the addition of B4C particles provided lower tendency to corrosion and lower corrosion kinetics under sliding, along with significantly reduced wear loss, mainly due to the load carrying effect given by the reinforcement particles. PMID:26866451

  5. Consolidation of B4C-TaB2 eutectic composites by spark plasma sintering

    Dmytro Demirskyi

    2015-01-01

    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.% TaB...

  6. A Comparative Survey on Optical Burst Switched Network Simulators

    Terrance Frederick Fernandez

    2014-04-01

    Full Text Available Optical Burst Switching (OBS is the future of optical internet which provides a promising architecture to efficiently utilize WDM and to fulfill today’s Internet traffic demands. Since this area is yet to mature there is a darn need to study its various protocols. Network simulator is an important tool for researchers and academicians to simulate and model the actual network at a reduced cost compared to the real test-bed experimentation. In this paper various OBS simulators are comparatively surveyed, while highlighting their merits and demerits.

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

    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.

  8. AGILE detection of enhanced gamma-ray emission from the FSRQ 4C +01.02

    Verrecchia, F.; Lucarelli, F.; Pittori, C.; Bulgarelli, A.; Tavani, M.; Fioretti, V.; Zoli, A.; Piano, G.; Striani, E.; Vercellone, S.; Donnarumma, I.; Cardillo, M.; Gianotti, F.; Trifoglio, M.; Giuliani, A.; Mereghetti, S.; Caraveo, P.; Perotti, F.; Chen, A.; Argan, A.; Costa, E.; Del Monte, E.; Evangelista, Y.; Feroci, M.; Lazzarotto, F.; Lapshov, I.; Pacciani, L.; Soffitta, P.; Sabatini, S.; Vittorini, V.; Pucella, G.; Rapisarda, M.; Di Cocco, G.; Fuschino, F.; Galli, M.; Labanti, C.; Marisaldi, M.; Pellizzoni, A.; Pilia, M.; Trois, A.; Barbiellini, G.; Vallazza, E.; Longo, F.; Morselli, A.; Picozza, P.; Prest, M.; Lipari, P.; Zanello, D.; Cattaneo, P. W.; Rappoldi, A.; Colafrancesco, S.; Parmiggiani, N.; Ferrari, A.; Antonelli, A.; Giommi, P.; Salotti, L.; Valentini, G.; D'Amico, F.

    2016-07-01

    AGILE is detecting increased gamma-ray emission above 100 MeV from a position consistent with the flat spectrum radio quasar 4C +01.02 (also known as 5BZQ J0108+0135, PKS 0106+01 and 3FGL J0108.7+0134), recently reported in flaring activity also by Fermi/LAT during the week Jun 6-12 (http://fermisky.blogspot.it).

  9. Brain pharmacokinetics of ganciclovir in rats with orthotopic BT4C glioma.

    Gynther, Mikko; Kääriäinen, Tiina M; Hakkarainen, Jenni J; Jalkanen, Aaro J; Petsalo, Aleksanteri; Lehtonen, Marko; Peura, Lauri; Kurkipuro, Jere; Samaranayake, Haritha; Ylä-Herttuala, Seppo; Rautio, Jarkko; Forsberg, Markus M

    2015-01-01

    Ganciclovir (GCV) is an essential part of the Herpes simplex virus thymidine kinase (HSV-tk) gene therapy of malignant gliomas. The purpose of this study was to investigate the brain pharmacokinetics and tumor uptake of GCV in the BT4C rat glioma model. GCV's brain and tumor uptakes were investigated by in vivo microdialysis in rats with orthotopic BT4C glioma. In addition, the ability of GCV to cross the blood-brain barrier and tumor vasculature was assessed with in situ rat brain perfusion. Finally, the extent to which GCV could permeate across the BT4C glioma cell membrane was assessed in vitro. The areas under the concentration curve of unbound GCV in blood, brain extracellular fluid (ECF), and tumor ECF were 6157, 1658, and 4834 μM⋅min, respectively. The apparent maximum unbound concentrations achieved within 60 minutes were 46.9, 11.8, and 25.8 μM in blood, brain, and tumor, respectively. The unbound GCV concentrations in brain and tumor after in situ rat brain perfusion were 0.41 and 1.39 nmol/g, respectively. The highly polar GCV likely crosses the fenestrated tumor vasculature by paracellular diffusion. Thus, GCV is able to reach the extracellular space around the tumor at higher concentrations than that in healthy brain. However, GCV uptake into BT4C cells at 100 μM was only 2.1 pmol/mg of protein, and no active transporter-mediated disposition of GCV could be detected in vitro. In conclusion, the limited efficacy of HSV-tk/GCV gene therapy may be due to the poor cellular uptake and rapid elimination of GCV. PMID:25349125

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

    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.

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

    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.

  12. Thermal safety analysis of aluminum matrix B4C irradiation in-pile

    Aluminum matrix B4C is a new structural material for spent fuel storage and related performances need in-depth research, especially the irradiation-resistance capability. The thermal calculations were completed by using the CFD software to ensure the safety of the in-pile irradiation test. Considering the characteristic of the irradiation project, the thermal safety feature of the in-pile test was analyzed, and the irradiation project was optimized. (authors)

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

    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. Experiment and analysis of B4C simulating control rod on FCA V-3 Assembly

    Reactivity worths of the B4C simulating control rods have been measured and analysed on FCA V-3 Assembly which was constructed as the engineering mock-up for Experimental Fast Reactor ''JOYO''. Assembly V-3 differs from JOYO in the blanket composition and the simulating control rod is 1/2 of that of JOYO in size. We have made efforts to check the adequacy of the nuclear design method and to improve the design accuracy for JOYO by determining the range of ratios of the theoretical to experimental values (C/E). The reactivity worth of the B4C control rod is obtained by the measurement of the sub-criticality of the system containing the control rod. In the present work the neutron source multiplication method was employed. In the calculation we employed the multigroup diffusion approximation for the core and blanket, and the collision probability method for the effective cross sections of the B4C simulating control rod region. The cross section set used in the calculation is JAERI-FAST Version II. The lowest limit of the sub-criticality of the system is -6% delta k/k and the C/E ranges from 1.00 to 1.03 in the present work. (author)

  15. Facile preparation of porous LiFePO4/C composite granules by mechanical process

    Lithium iron phosphate (LiFePO4) which is a promising cathode material for lithium-ion batteries requires particle size reduction, carbon coating and granulation to improve its electrochemical performances and increase the energy densities. In addition, their composite granules desire a porous structure in order to assist the penetration of liquid electrolyte. Here, we report a facile preparation of porous LiFePO4/C composite granules by a mechanical method using an attrition-type mill. By the mechanical treatment of starting materials, LiFePO4/C composite granules with an average pore size of 20–30 nm were synthesized in one-step process without atmosphere control and external heating. This simple mechanical technique does not require additional pore forming agents. According to the cell tests, a favorable cycle performance was exhibited. - Highlights: • Porous LiFePO4/C composite granule was synthesized by one-pot mechanical process. • LiFePO4 was formed without atmosphere control and external heating. • Gases released from raw materials act as pore forming agents. • A favorable cycle performance was exhibited

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

    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.

  17. AGN feedback and iron enrichment in the powerful radio galaxy, 4C+55.16

    Hlavacek-Larrondo, J; Sanders, J S; Taylor, G B

    2011-01-01

    We present a detailed X-ray analysis of 4C+55.16, an unusual and interesting radio galaxy, located at the centre of a cool core cluster of galaxies. 4C+55.16 is X-ray bright (~10^45 erg/s), radio powerful, and shows clear signs of interaction with the surrounding intracluster medium. By combining deep Chandra (100 ks) with 1.4 GHz VLA observations, we find evidence of multiple outbursts from the central AGN, providing enough energy to offset cooling of the ICM (P_bubbles=6.7x10^44 erg/s). Furthermore, 4C+55.16 has an unusual intracluster iron distribution showing a plume-like feature rich in Fe L emission that seems to run along one of the X-ray cavities. The excess of Fe associated with the plume is around 10^7M_sol. The metal abundances are consistent with being Solar-like, indicating that both SNIa and SNII contribute to the enrichment. The plume and southern cavity form a region of cool metal-rich gas. At the edge of this region, there is a clear discontinuity in temperature (from kT~2.5 keV to kT~5.0 keV...

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

    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. RC4c : A Secured Way to View Data Transmission in Wireless Communication Networks

    O. O Olakanmi,

    2012-04-01

    Full Text Available In spite of several crypto analytical criticisms on RC4 data encryption algorithm, its simplicity, speed has made it one of the popular encryption techniques employ in wireless communication networks. However, in recent time many experts no longer consider RC4 secure against attacks. This is due to some vulnerability detected through repetition of keys over a period of time. This exposes the weakness of the exclusive OR operator on which the RC4 technique is anchored. In recent time, another variant of RC4 was developed called RC42s. This encryption algorithm innovatively solves the problem of mutual exclusive of XOR operator in RC4; however, the experimental result shows the improvement rate of 68% over RC4. That is, 32% of encrypted messages are susceptible to hacking whenever there is key collision. In this paper, a novel method is developed to counter the negative effect of the mutual exclusiveness of the functional operator on RC4 and RC42s. The new technique called RC4c uses 2s complement and shifting operation to give a perfect and secured data encryption technique for wireless network. Performance analysis on speed and effect of mutual exclusiveness of XOR on RC4, RC42s and RC4c security was done. It was discovered that RC4c not only completely nullifies the weakness introduced by mutual exclusiveness of XOR in RC4 and RC42s but maintains the simplicity and throughput of the RC4 and RC42s.

  20. Laser controlled melting of HSLA steel surface with presence of B{sub 4}C particles

    Yilbas, B.S., E-mail: bsyilbas@kfupm.edu.sa [ME Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Patel, F., E-mail: faheemmp@kfupm.edu.sa [ME Department, King Fahd University of Petroleum and Minerals, Dhahran (Saudi Arabia); Karatas, C., E-mail: doc_cihan@hotmail.com [Engineering College, Hacettepe University (Turkey)

    2013-10-01

    Laser gas assisted melting of high strength low alloy steel surface is carried out. The alloy surface is pre-prepared to contain 5% B{sub 4}C particles in a 40 μm thick carbon film prior to laser treatment process. Metallurgical and morphological changes in the laser treated layer are examined by using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The residual stress developed and the microhardness of the resulting surface is measured. It is found that B{sub 4}C particles remain in solid phase in the surface region due to their high melting temperature. The dense layer consisting of fine grains are formed at the surface and the feathery like structure is observed below the surface vicinity, which consists of martensite and nitride precipitations. The use of nitrogen at high pressure causes the formation of nitride compounds at the surface, which contributes to the volume shrinkage in the dense layer. Surface microhardness increases considerably because of attainment of high cooling rates, formation of nitride compounds, and presence of B{sub 4}C particles at the surface. .

  1. Laser controlled melting of HSLA steel surface with presence of B4C particles

    Yilbas, B. S.; Patel, F.; Karatas, C.

    2013-10-01

    Laser gas assisted melting of high strength low alloy steel surface is carried out. The alloy surface is pre-prepared to contain 5% B4C particles in a 40 μm thick carbon film prior to laser treatment process. Metallurgical and morphological changes in the laser treated layer are examined by using scanning electron microscopy, energy dispersive spectroscopy, and X-ray diffraction. The residual stress developed and the microhardness of the resulting surface is measured. It is found that B4C particles remain in solid phase in the surface region due to their high melting temperature. The dense layer consisting of fine grains are formed at the surface and the feathery like structure is observed below the surface vicinity, which consists of martensite and nitride precipitations. The use of nitrogen at high pressure causes the formation of nitride compounds at the surface, which contributes to the volume shrinkage in the dense layer. Surface microhardness increases considerably because of attainment of high cooling rates, formation of nitride compounds, and presence of B4C particles at the surface.

  2. Evolution of reinforcement distribution in Al-B4C composites during accumulative roll bonding

    Highlights: → ARB developed a nanostructure in the matrix of the Al-B4C composite. → An improvement in the reinforcement distribution was found by increasing ARB passes. → By progression of ARB from one to seven passes, hardness increased from 60 to 82 HV. -- Abstract: The distribution of reinforcement particles in the matrix of a composite is one of the most important microstructural features affecting properties. In this study, nanostructured Al-B4C composite sheets were processed by accumulative roll bonding (ARB), and the effect of the number of ARB cycles on the distribution of the B4C particles in the Al matrix was evaluated. From optical microscopic studies accompanied by the radial distribution function analysis, it was realized that the microstructure uniformity is improved by increasing the number of ARB cycles. It was in good agreement with bulk hardness measurements in which the standard deviation of the hardness values was decreased by progression of the ARB process. In addition, the X-ray diffraction peak profile analysis revealed that the area weighted mean crystallite size of the Al matrix decreases to the nanometric scale (114 nm) after seven ARB cycles.

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

    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...

  4. VizieR Online Data Catalog: RVs & V-band LCs of probable members of Cyg OB2 (Kiminki+, 2015)

    Kiminki, D. C.; Kobulnicky, H. A.; Vargas Alvarez, C. A.; Alexander, M. J.; Lundquist, M. J.

    2016-01-01

    Optical spectroscopic observations of the four targets were obtained as part of the Cygnus OB2 Radial Velocity Survey on numerous dates between 2001 and 2011 using a variety of telescopes and instruments as described in Papers I-IV (see References section below) of this series. Several additional observations were obtained in 2012 October (on MT91 696 and Schulte 3) and 2013 May-June (on MT91 372) using the Wyoming Infrared Observatory (WIRO). Photometry of MT91 696 was obtained on nine nights between 2012 October 17 and November 10 at the University of Wyoming 0.6m Red Buttes Observatory (RBO). Data on Schulte 3 was obtained on 14 nights at RBO between 2012 October 17 and December 21, and data on CPR2002 A36 was obtained on four nights between 2012 December 10 and 22. Photometry of MT91 372 was also obtained at RBO on seven nights between 2013 June 14 and July 8. (6 data files).

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

    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

  6. Massive Variability Surveys from Venezuela

    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...

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

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

    2014-01-01

    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...... is used to study the capacity and power capability degradation behaviour of the tested nanophosphate LiFePO4/C battery for two electric vehicle operational scenarios....

  8. Measuring the rotation periods of 4-10 Myr T-Tauri stars in the Orion OB1 association

    Tanveer Karim, Md; Stassun, Keivan; Briceno, Cesar; Vivas, Kathy; Raetz, Stefanie; Calvet, Nuria; Mateu, Cecilia; Downes, Juan Jose; Hernandez, Jesus; Neuhäuser, Ralph; Mugrauer, Markus; Takahashi, Hidenori; Tachihara, Kengo; Chini, Rolf; YETI

    2016-01-01

    Most existing studies of young stellar populations have focused on the youngest (natal gas and hence easier to identify. In contrast, older T-Tauri stars (~ 4-10 Myr), being more difficult to find, have been less studied, even though they hold key insight to understanding evolution of lower-mass (0.1-2 M⊙) stars and of protoplanetary discs. We present a study of photometric variability of 1974 confirmed 4-10 Myr old T-Tauri stars in the Orion OB1 association using optical time-series from three different surveys: the Centro de Investigaciones de Astronomía-Quest Equatorial Survey Team (CIDA-QUEST), the Young Exoplanet Transit Initiative (YETI) and from a Kitt Peak National Observatory (KPNO) campaign. We investigated stellar rotation periods according to the type of stars (Classical or Weak-lined T-Tauri stars) and their locations, to look for population-wide trends. We detected 563 periodic variables and 1411 non-periodic variables by investigating the light curves of these stars. We find that ~ 30% of Weak-line T-Tauri stars (WTTS) and ~ 20% of Classical T-Tauri stars (CTTS) are periodic. Though we did not find any noticeable difference in rotation period between CTTS and WTTS, our study does show a change in the overall rotation periods of stars 4-10 Myr old, consistent with predictions of angular momentum evolution models, an important constraint for theoretical models for an age range for which no similar data existed.

  9. Highly Accelerated Diamagnetic Plasmoids: A New X-ray Production Mechanism for OB Stellar Winds

    Waldron, Wayne L

    2009-01-01

    The observed X-ray source temperature distributions in OB stellar winds, as determined from high energy resolution Chandra observations, show that the highest temperatures occur near the star, and then steadily decrease outward through the wind. To explain this unexpected behavior, we propose a shock model concept that utilizes a well-known magnetic propulsion mechanism; the surface ejection of "diamagnetic plasmoids" into a diverging external magnetic field. This produces rapidly accelerating self-contained structures that plow through an ambient wind and form bow shocks that generate a range in X-ray temperatures determined by the plasmoid-wind relative velocities. The model free parameters are the plasmoid initial Alfven speed, the initial plasma-beta of the external medium, and the divergence rate of the external field. These are determined by fitting the predicted bow shock temperatures with the observed OB supergiant X-ray temperature distribution. We find that the initial external plasma-beta has a ran...

  10. Ara OB1 - A stellar association formed by the action of an energetic event?

    Arnal, E. M.; Cersosimo, J. C.; May, J.; Bronfman, L.

    1987-01-01

    Neutral hydrogen (at the wavelength of 21 cm) and carbon monoxide (at 2.6 mm) line observations of the interstellar medium in the neighborhood of the association Ara OB1 are reported. The observed H I distribution indicates the presence of an expanding structure. The total H I mass associated with such feature amounts to 4800 solar masses, and its momentum and kinetic energy are about 40,000 solar mass km/s and 3 x 10 to the 48th erg, respectively. The H I structure, 42 pc in diameter, expands at a speed of 10 km/s. A possible origin for the expanding H I structure, and a genetic link between such structure and Ara OB1 are proposed.

  11. Proposal of a multi-layer network architecture for OBS/GMPLS network interworking

    Guo, Hongxiang; Tsuritani, Takehiro; Yin, Yawei; Otani, Tomohiro; Wu, Jian

    2007-11-01

    In order to enable the existing optical circuit switching (OCS) network to support both wavelength and subwavelength granularities, this paper proposes overlay-based multi-layer network architecture for interworking the generalized multi-protocol label switching (GMPLS) controlled OCS network with optical burst switching (OBS) networks. A dedicated GMPLS border controller with necessary GMPLS extensions, including group label switching path (LSP) provisioning, node capability advertisement, and standard wavelength label as well as wavelength availability advertisement, is introduced in this multi-layer network to enable a simple but flexible interworking operation. The feasibility of this proposal is experimentally confirmed by demonstrating an OBS/GMPLS testbed, in which the extended node capability advertisement and group LSP functions successfully enabled the burst header packet (BHP) and data burst (DB) to transmit over a GMPLS-controlled transparent OCS network.

  12. The genesis of hydrocarbons in the area of the Ob' River Mouth (Kara Sea)

    This paper reported on a study in which the spatial distribution of hydrocarbons in the surface waters of the Obskaya Guba and the Kara Sea was investigated, with particular reference to the area of the Ob'River mouth. Aliphatic hydrocarbons and polyaromatic hydrocarbons in dissolved and particulate forms and sediments were compared to the particulate matter and organic carbon in the area. The structure of hydrocarbons in the study area was found to be influenced by the mixture of fresh and salty waters that promotes the transformation of anthropogenic and natural compounds. The study showed that the highest accumulation of hydrocarbons was in the physicochemical area of the marginal filter in the field of avalanche sedimentation. The area of the Ob'River mouth significantly reduces the amount of hydrocarbon pollution released into the Kara Sea. 15 refs., 1 tab.

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

    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.

  14. Detection of a Large Arc of Ionized Hydrogen Far Above the Cas OB6 Association A Superbubble Blowout into the Galactic Halo?

    Reynolds, R J; Haffner, L M

    2001-01-01

    The Wisconsin H-Alpha Mapper (WHAM) Northern Sky Survey has revealed a loop of H II reaching 1300 pc from the Galactic midplane above the Cas OB6 association in the Perseus sprial arm. This enormous feature surrounds and extends far above the "W4 Chimney" identified by Normandeau et al. and appears to be associated with the star formation activity near the W3/W4/W5 H II region complex. The existence of this ionized structure suggests that past episodes of massive star formation have cleared the H I from an enormous volume above the Perseus arm, allowing Lyman continuum photons from O stars near the Galactic midplane to reach into the halo.

  15. Pharmacological Effects of the Water Fraction of Key Components in the Traditional Chinese Prescription Mai Tong Fang on 3T3-L1 Adipocytes and ob/ob Diabetic Mice

    Liang Ma; Li Huang; Heying Pei; Zhuowei Liu; Caifeng Xie; Lei Lei; Xiaoxin Chen; Haoyu Ye; Aihua Peng; Lijuan Chen

    2014-01-01

    Mai Tong Fang (MTF), a Chinese herbal combination, has been used for the treatment of diabetic nephropathy in traditional medical clinics in China. However, the anti-adipogenic and anti-hyperglycemic effects of MTF have not been fully elucidated, so this study explored these pharmacological activities in 3T3-L1 adipocytes and ob/ob mice, respectively, of the water fraction of milkvetch root, salviae miltiorrhizae and mulberry as key components of MTF. MTF was found to inhibit adipogenesis and...

  16. The asymmetric radio structure and record jet of giant quasar 4C 34.47

    Hocuk, S.; Barthel, P. D.

    2010-11-01

    Context. Unification models for active galactic nuclei, AGN, predict that all quasars (radio sources associated with quasi-stellar objects) should be at a substantial angle with the sky plane. Aims: We test the predictions of the orientation unification model with the morphological and polarization properties of a giant quasar. Methods: The giant double-lobed radio source 4C 34.47, which is associated with quasi-stellar object B1721+343, is mapped at arcsecond scale resolution, and the data are subsequently analyzed within the context of current models for extragalactic radio sources. Results: Quasar 4C 34.47 displays a straight one-sided jet, measuring a record length of 380 kpc in its double-lobed radio structure. Assuming an intrinsically symmetric two-sided jet structure the radio source jet axis must be at least 33° away from the sky plane, that is within 57° from the line of sight. The radio polarization properties indicate that this giant source has largely outgrown the depolarizing halo that is generally associated with the host galaxies of powerful radio sources. The measured small depolarization asymmetry nevertheless agrees with its inferred orientation. Conclusions: All data for this giant radio source agree with its preferred orientation as predicted within the unification scheme for powerful radio sources. Seen under a small aspect angle the radio source is large, but not excessively large. The global properties of 4C 34.47 do not differ from other giant (old) FR2 radio sources: it is a slowly expanding low-luminosity radio source.

  17. Influence on spacecraft control systems of evolving O/B technology and standards

    Creasey, Richard

    1990-10-01

    Analysis of the operation requirements of future spacecraft show that past approaches are not sufficient. The use of on board (O/B) technology and the development of the specific standards are proposed in order to meet those increasing requirements. The increase in on board decision making capability in spacecraft is discussed. Standardization of spacecraft operations and the impact on present and future ESA standards by this trend are considered.

  18. Escape fraction of ionizing photons during reionization: Effects due to supernova feedback and runaway ob stars

    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, SN, feedback, and runaway OB stars) on the escape fraction (f esc) at the epoch of reionization (z ≥ 7). We implement a new, physically motivated SN 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 SN feedback. Consequently, the photon number-weighted mean escape fraction for dwarf galaxies in halos of mass 108-1010.5 M ☉ is found to be 〈fesc〉∼11%, although instantaneous values of f esc > 20% are common when star formation is strongly modulated by the SN explosions. We find that the inclusion of runaway OB stars increases the mean escape fraction by 22% to 〈fesc〉∼14%. As SNe resulting from runaway OB stars tend to occur in less dense environments, the feedback effect is enhanced and star formation is further suppressed in halos with Mvir≳109 M⊙ in the simulation with runaway OB stars compared with the model without them. While both our models produce enough ionizing photons to maintain a fully ionized universe at z ≤ 7 as observed, a still higher amount of ionizing photons at z ≥ 9 appears necessary to accommodate the high observed electron optical depth inferred from cosmic microwave background observations.

  19. Detoxification of Mercury by Methanobactin from Methylosinus trichosporium OB3b

    Vorobev, Alexey; Jagadevan, Sheeja; Baral, Bipin S.; DiSpirito, Alan A.; Freemeier, Brittani C.; Bergman, Brandt H.; Bandow, Nathan L.; Semrau, Jeremy D.

    2013-01-01

    Many methanotrophs have been shown to synthesize methanobactin, a novel biogenic copper-chelating agent or chalkophore. Methanobactin binds copper via two heterocyclic rings with associated enethiol groups. The structure of methanobactin suggests that it can bind other metals, including mercury. Here we report that methanobactin from Methylosinus trichosporium OB3b does indeed bind mercury when added as HgCl2 and, in doing so, reduced toxicity associated with Hg(II) for both Alphaproteobacter...

  20. Hydraulic analysis of water supply system Šmartno ob Paki

    Stropnik, Petra

    2006-01-01

    The subject of the Graduation Project is the hydraulics of the Šmartno ob Paki water supply system. The primary focus is on the analysis of pressure and flow conditions using the appropriate software tools, and the optimisation of the existing situation. The Graduation Project features a theoretical and a practical part. The theoretical part includes all the bases required for hydraulic modelling, and the calculations and analysis of hydraulic conditions, while the practical part involves the...

  1. FUV Spectroscopy of the sdOB Primary of the Eclipsing Binary System AA Dor

    Fleig, Johannes; Werner, Klaus; Kruk, Jeffrey W

    2007-01-01

    AA Dor is an eclipsing, close, post common-envelope binary (PCEB). We present a detailed spectral analysis of its sdOB primary star based on observations obtained with the Far Ultraviolet Spectroscopic Explorer (FUSE). Due to a strong contamination by interstellar absorption, we had to model both, the stellar spectrum as well as the interstellar line absorption in order to reproduce the FUV observation well and to determine the photospheric parameters precisely.

  2. Degradation of Trichloroethylene by Methanol-Grown Cultures of Methylosinus trichosporium OB3b PP358

    Fitch, M. W.; Speitel, G. E.; Georgiou, G.

    1996-01-01

    A soluble methane monooxygenase-constitutive mutant strain of Methylosinus trichosporium OB3b, strain PP358, was grown with methanol as the carbon source, and the kinetics of trichloroethylene (TCE) degradation were determined. PP358 exhibited high TCE degradation rates under both oxygen- and carbon-limiting conditions. The optimal pseudo first-order rate constant for TCE was comparable to the values measured for cells grown with methane. We found that growth under oxygen-limiting conditions ...

  3. Kinetics of chlorinated hydrocarbon degradation by Methylosinus trichosporium OB3b and toxicity of trichloroethylene.

    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 readily degraded included chloroform, trans-1,2-dichloroethylene, and TCE, with V(max) values of 550, 330, and 290 nmol min-1 mg of cells-1, respectively. 1,1-Dichloroethylene was a very poor substra...

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

    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.

  5. American-Sino OB/GYN/Pediatrics Services (ASOG), Shanghai Business Plan 2012-16

    Ding, Haohong; Jacob, Mathew

    2012-01-01

    The sincere support from the Management leadership is highly appreciated for providing the fundamental operating information and knowledge on the professional industry technologies. The business plan analyses the current situation of ASOG, the trends of OB/GYN industry and customers’ needs. The results are further narrowed down to frame the mission and vision statements, identify a new strategy, develop and suggest implementing the feasible tactics that will lead the sustainable developmen...

  6. LOCALIZATION FEATURES OF GEOCHEMICAL TYPES OF UNDERGROUND WATER OF OB-TOMSKOYE INTERFLUVIAL

    Yankovich E. P.

    2015-03-01

    Full Text Available The chemical composition of neogen-quaternary, paleogene, cretaceous and paleozoic aquifer systems in the Ob-Tomskoye interfluves area is presented in the article. The water saturation with respect to secondary minerals is described. Authors show that the waters of all studied aquifer systems are saturated with respect to montmorillonites and calcite in a less degree. The geochemical water types are identified and their distribution is described

  7. The INGV's new OBS/H: Analysis of the signals recorded at the Marsili submarine volcano

    D'Alessandro, A.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione OV, Napoli, Italia; D'Anna, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia; Luzio, D.; CFTA, University of Palermo; Mangano, G.; Istituto Nazionale di Geofisica e Vulcanologia, Sezione CNT, Roma, Italia

    2009-01-01

    The ocean bottom seismometer with hydrophone deployed on the flat top of the Marsili submarine volcano (790 m deep) by the Gibilmanna OBS Lab (CNT–INGV) from 12th to 21st July, 2006, recorded more than 1000 transient seismic signals. Nineteen of these signals were associated with tectonic earthquakes: 1 teleseismic, 8 regional (located by INGV) and 10 small local seismic events (non located earthquakes). The regional events were used to determine sensor orientation. By comparing t...

  8. Identification of current attacks and their counter measures in Optical Burst Switched (OBS) network

    Siddharth Singh Chouhan; Prof. Sanjay Sharma

    2012-01-01

    As day by day application grows internet requires large amount of bandwidth. Optical Burst Switching (OBS) is the next generation optical Internet with IP over WDM as the core architecture. It can achieve a balance between Optical Circuit Switching (OCS) and Optical Packet Switching (OPS). Optical network supports huge bandwidth and transmits data at an average rate of 50Tb/s. But we need to exploit the fiber’s huge bandwidth through WDM which is the current favorite multiplexing technology i...

  9. Unusual character of the radioemission of the OB star association in the Scorpius constellation

    The results of the observations of the Sco OB 2 association at the wavelength of 7,6 cm are given. The catalogue of 82 sources was compiled, the great majority of which have small angular sizes. An excess of the objects with nonthermal spectra is revealed, the distribution of which in the map plane is nonuniform. 10% of the sources have inversion spectra; these are compact H II regions with the lifetime 3 years

  10. Synthetic LiFePO4/C without using inert gas

    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.

  11. Core and halo structure of the quasar 4C 18. 68

    Gower, A.C.; Hutchings, J.B.

    1986-08-01

    New VLA observations of the complex low-redshift quasar 4C 18.68, which was previously modeled as a precessing twin-jet source are presented. A 2-cm A configuration map fails to reveal the curvature of the jet near the nucleus predicted by this model. B and C configuration maps have been obtained to study the halo of the source, which is compact and shows no edge-brightened outer lobes. These results suggest that the radio source is not very old, and that it appears to have undergone two major changes of orientation in its less than 10 to the 7th yr history. 8 references.

  12. Core and halo structure of the quasar 4C 18.68

    New VLA observations of the complex low-redshift quasar 4C 18.68, which was previously modeled as a precessing twin-jet source are presented. A 2-cm A configuration map fails to reveal the curvature of the jet near the nucleus predicted by this model. B and C configuration maps have been obtained to study the halo of the source, which is compact and shows no edge-brightened outer lobes. These results suggest that the radio source is not very old, and that it appears to have undergone two major changes of orientation in its less than 10 to the 7th yr history. 8 references

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

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

    2014-01-01

    inhibitors developed up-to-date target either the cofactor- or substrate-binding sites of these enzymes, resulting in a lack of selectivity and off-target effects. This study describes the discovery of the first peptide-based inhibitors of KDM4 histone demethylases that do not share the histone peptide...... 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....

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

    Joensen, Karsten D.; Gorenstein, Paul; Christensen, Finn Erland; Gutman, George

    1994-01-01

    Traditional high-Z coated X-ray telescopes for the >= 1 keV range all have a loss of throughput with higher energies, owing to the inverse proportionality between the critical angle and energy. We have shown that this can, to some degree, be countered by employing multilayers on the outermost...... reflectors. A W/B4C multilayer has been fabricated and its 8 keV X-ray reflectivity measured and modeled, yielding an interface-roughness of 3.6 angstroms. This measurement and the resulting model-fit form the basis for computing the performance of `AXAF-S'-sized conical and Kirkpatrick-Baez telescopes...

  15. The warm absorber in the radio-loud quasar 4C +74.26

    Di Gesu, L.; Costantini, E.

    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 Grat...

  16. Morphological research on radio loud AGN 4C39.25 using KaVA observations

    Yoo, Hyemin; Sohn, Bong Won; Yi, Sukyoung; KaVA AGN WG members

    2016-01-01

    4C39.25 (0923+392) is a distant radio loud AGN placed at redshift 0.695. Its kilo-parsec scale jet observed by VLBA(Kollgaard et al. 1990) and parsec scale jet observed by VLBA(Kellermann et al. 1998) are misaligned. This might indicate episodic-jet activity which recently turned on. This object currently shows two stationary compact parsec-scale components:a bright jet component on the east and less luminous core on the west. Also, it is known that there have been superluminal jet components which are flowing from the core toward east, and then merging with the bright jet component (Marscher et al. 1991, Alberdi et al. 2000, Lister et al. 2013). Including the detection of broad emission lines(SDSS), its viewing angle was concluded to be small. However, the jet component being more luminous than the core is abnormal for a source with a small viewing angle. Furthermore, it has young radio galaxy-like properties such as non-variation in total flux(Alberdi et al. 1997, 2000, MOJAVE database) and a high frequency peak in the spectral energy distribution(Orienti et al 2007). In this case, it is more reliable to think that viewing angle of 4C39.25 is large. Korean VLBI Network (KVN) and VLBI Exploration of Radio Astronomy (VERA) Array (KaVA) is a cooperated VLBI system of Korea and Japan which provides high-frequency (23GHz and 43GHz) and high spatial resolution(1.2mas and 0.6mas). Their advantages of multi-wavelength and relatively high S/N ratio relative to its number of baseline allow us to discover the central region and dim structures of 4C39.25. We present results of several epochs observed during 2013 to 2014, focusing on morphological changes of 4C39.25 using KaVA images. According to these results, we were able to find a recently emitted counter-jet component for images of first 6 epochs. Also the counter-jet component propagates along a curved trajectory, and it shows an extreme superluminal motion. This might indicate a necessity of relatively large viewing

  17. Haploinsufficiency of p18INK4c Sensitizes Mice to Carcinogen-Induced Tumorigenesis

    Bai, Feng; Pei, Xin-Hai; Godfrey, Virginia L.; Xiong, Yue

    2003-01-01

    The INK4 family of cyclin-dependent kinase (CDK) inhibitors negatively regulates cyclin D-dependent CDK4 and CDK6 and thereby retains the growth-suppressive function of Rb family proteins. Mutations in the CDK4 gene conferring INK4 resistance are associated with familial and sporadic melanoma in humans and result in a wide spectrum of tumors in mice. Whereas loss of function of other INK4 genes in mice leads to little or no tumor development, targeted deletion of p18INK4c causes spontaneous p...

  18. 4C 的(r1,r2,r3,r4)−冠的优美性%The gracefulness of the (r1, r2, r3, r4)−corona of the cycle 4C

    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.

  19. Predicting Gaia's Parallax Distance to the Cygnus OB2 Association with Eclipsing Binaries

    Kiminki, Daniel C; Álvarez, Carlos A Vargas; Alexander, Michael J; Lundquist, Michael J

    2015-01-01

    The Cygnus OB2 Association is one of the nearest and largest collections of massive stars in the Galaxy. Situated at the heart of the "Cygnus X" complex of star-forming regions and molecular clouds, its distance has proven elusive owing to the ambiguous nature of kinematic distances along this $\\ell\\simeq80$ degree sightline and the heavy, patchy extinction. In an effort to refine the three-dimensional geometry of key Cygnus~X constituents, we have measured distances to four eclipsing double-lined OB-type spectroscopic binaries that are probable members of Cyg~OB2. We find distances of $1.33\\pm0.17$, $1.32\\pm0.07$, $1.44\\pm0.18$, and $1.32\\pm0.13$ kpc toward MT91~372, MT91~696, CPR2002~A36, and Schulte~3 respectively. We adopt a weighted average distance of 1.33$\\pm$0.06~kpc. This agrees well with spectrophotometric estimates for the Association as a whole and with parallax measurements of protostellar masers in the surrounding interstellar clouds, thereby linking the ongoing star formation in these clouds wi...

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

    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.

  1. New VI photometry of the sdOB binary AA Dor and an improved photometric model

    Hilditch, R W; Lynas-Gray, A E; Hill, G

    2003-01-01

    New VI CCD photometry, obtained with integration times of 20s, of the sdOB+degenerate-dwarf eclipsing binary system AA Dor has provided new complete light curves with an rms scatter about a mean curve of +/-0.004 mag. These data are analysed with an improved Light2 light curve synthesis code to yield more accurate determinations of the radii of both stars, the orbital inclination, and the flux ratio between the two components. These radii are only a little different from the values derived 25 years ago from less complete data, but the uncertainties on these values are improved by a factor of two. The apparent discrepancy remains between the surface gravity of the sdOB primary star obtained from the light-curve solution with the published spectroscopic orbit and that obtained from NLTE analysis of high-resolution spectra of the sdOB star. The substantial reflection effect in the system is adequately represented by the Light2 code with a bolometric albedo of unity in light curves extending from 0.35 microns to ...

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

    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...

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

    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...

  4. Clustering between high-mass X-ray binaries and OB associations in the Milky Way

    Bodaghee, Arash; Rodriguez, Jerome; James, J Berian

    2011-01-01

    We present the first direct measurement of the spatial cross-correlation function of high-mass X-ray binaries (HMXBs) and active OB star-forming complexes in the Milky Way. This result relied on a sample containing 79 hard X-ray selected HMXBs and 458 OB associations. Clustering between the two populations is detected with a significance above 7-sigmas for distances < 1 kpc. Thus, HMXBs closely trace the underlying distribution of the massive star-forming regions that are expected to produce the progenitor stars of HMXBs. The average offset of 0.4+-0.2 kpc between HMXBs and OB associations is consistent with being due to natal kicks at velocities of the order of 100+-50 km/s. The characteristic scale of the correlation function suggests an average kinematical age (since the supernova phase) of ~4 Myr for the HMXB population. Despite being derived from a global view of our Galaxy, these signatures of HMXB evolution are consistent with theoretical expectations as well as observations of individual objects.

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

    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.

  6. OB glue paste technique for establishing nude mouse human gastric cancer orthotopic transplantation models

    Jun Shi; Guo-Jing Zheng; Xiao-Mei Su; Ya-Lin Chen; Yan-Fang Liu; Ling Xu; Pin-Kang Wei; Shen Zhang; Zhi-Feng Qin; Jun Li; Da-Zhi Sun; Yan Xiao; Zhi-Hong Yu; Hui-Ming Lin

    2008-01-01

    AIM: To establish nude mouse human gastric cancer orthotopic transplantation models using OB glue paste technique.METHODS: Using OB glue paste technique,orthtopic transplantation models were established by implanting SGC-7901 and MKN-45 human gastric cancer cell strains into the gastric wall of nude mice.Biological features,growth of the implanted tumors,the success rate of transplantation and the rate of auto-metastasis of the two models were observed.RESULTS: The success rates of orthotopic transplantation of the two models were 94.20% and 96%.The rates of hepatic metastasis,pulmonary metastasis,peritoneal metastasis,lymphocytic metastasis and splenic metastasis were 42.13% and 94.20%,48.43% and 57.97%,30.83% and 36.96%,67.30% and 84.06%,and 59.75% and 10.53%,respectively.The occurrence of ascites was 47.80% and 36.96%.CONCLUSION: OB glue paste technique is easy to follow.The biological behaviors of the nude mouse human gastric cancer orthotopic transplantation models established with this technique are similar to the natural processes of growth and metastasis of human gastric cancer,and,therefore,can be used as an ideal model for experimental research of proliferative metastasis of tumors.

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

    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 (~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.

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

    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...

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

    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...

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

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

    2016-05-01

    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 spectrophotometric 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 report the detection of a second component of MT304, and discovery of an even fainter third component, based on data of speckle interferometric observations taken with the Russian 6-m telescope.

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

    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.

  12. A state-of-the-art report on the development of B{sub 4}C materials as neutron absorbers

    Jung, Choong Hwan; Kim, Sun Jae; Park, Jee Yun; Kang, Dae Kab [Korea Atomic Energy Research Institute, Taejon (Korea, Republic of)

    1994-01-01

    Boron of 10 atomic weight is one of the best neutron absorbing elements. Among the boron compounds, B{sub 4}C and its composites exhibit excellent material properties. Those materials absorb thermal and fast neutrons, are thermally and chemically very stable, and are very strong in mechanical properties. By neutron irradiation B-10 transforms into Li releasing one He atom. This He release causes swelling, cracking and fragmentation of B{sub 4}C bulks and results in degradation of the materials. The essence of technical developments of B{sub 4}C-based neutron absorbers is the minimization of the effects of He release, and this can be realized through microstructural optimizations of grain and porosity distributions. While pure B{sub 4}C is very difficult in sintering, new neutron absorbing materials of B{sub 4}C-cermets are being developed. B{sub 4}C-cermets are composite materials in which B{sub 4}C powders are dispersed in the metal matrix of Al or Cu. Those materials show easiness in sintering, mechanical forming, and B{sub 4}C content controlling. Neutron absorbing and shielding materials play an important role for the safety of reactor operations and environmental protections. Those materials are being used as monolithic pellets for control rods, burnable poison fuel rods, rack materials for spent fuel storages, shielding materials for shipping casks, and especially for shielding plates for liquid metal reactors. 37 figs., 12 tabs., 41 refs. (Author).

  13. C9orf72 G(4)C(2) repeat expansions in Alzheimer's disease and mild cognitive impairment

    Cacace, Rita; Van Cauwenberghe, Caroline; Bettens, Karolien; Gijselinck, Ilse; van der Zee, Julie; Engelborghs, Sebastiaan; Vandenbulcke, Mathieu; Van Dongen, Jasper; Baumer, Veerle; Dillen, Lubina; Mattheijssens, Maria; Peeters, Karin; Cruts, Marc; Vandenberghe, Rik; De Deyn, Peter P.; Van Broeckhoven, Christine; Sleegers, Kristel

    2013-01-01

    C9orf72 G(4)C(2) repeat expansion is a major cause of amyotrophic lateral sclerosis and frontotemporal lobar degeneration. Its role in Alzheimer's disease (AD) is less clear. We assessed the prevalence of G(4)C(2) pathogenic repeat expansions in Flanders-Belgian patients with clinical AD or mild cog

  14. The design, microstructure and tensile properties of B{sub 4}C particulate reinforced 6061Al neutron absorber composites

    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.

  15. Surface quality improvement of B4C particles for electroless copper coating by Cu activation and oxidation roughening methods

    Highlights: • Cu activation increases surface activity by depositing Cu nano-crystals on B4C. • The best result of Cu activation comes out at pH 12. • Oxidation roughening improves wettability of B4C by aqueous solution. • Oxidation roughening promotes Cu nucleation on B4C surface. - Abstract: Surface quality improvement by Cu activation and oxidation roughening process was studied during electroless coating Cu on boron carbide (B4C) particles. The surface morphology was characterized by scanning electron microscope (SEM) and the phase identification was determined by X-ray diffraction (XRD) analysis. Two aspects concluding surface activation and surface roughening were investigated to understand the effect of each on Cu coating. Cu activation process increased surface activity of B4C by pre-deposition Cu nano-crystals, which was effective and cost-saving when compared with conventional Pd activation method. The influence of activation pH on electroless Cu coating was discussed and a moderate pH 12 is suitable for Cu deposition. Surface roughening process availably promoted wettability of B4C particles with aqueous solution. Etched pits were formed on B4C surface and resulted in fresh surface exposed after oxidization roughening process, which was beneficial for Cu bonding and coating on B4C surface

  16. Al-Si/B4C composite coatings on Al-Si substrate by plasma spray technique

    Plasma-sprayed coatings of Al-Si/B4C have been prepared on Al-Si piston alloys for diesel engine motors. The Al-Si/B4C composite powders including 5-25 wt% B4C were prepared by mixing and ball-milling processes. These powders were deposited on Al-Si substrate using an atmospheric plasma spray technique. The coatings have been characterised with respect to phase composition, microstructure, microhardness, bond strength and thermal expansion. It was found that Al, Si, B4C and Al2O3 phases were determined in the coatings with approximately 600 μm thick by using X-ray diffraction analysis. Scanning electron microscope observation revealed that boron carbide particles were uniformly distributed in composite coatings and B4C particles were fully wetted by Al-Si alloy. Also, no reaction products were observed in Al-Si/B4C composite coatings. It was found that surface roughness, porosity, bond strength and thermal expansion coefficient of composite coatings decreased with increasing fraction of the boron carbide particle. It was demonstrated that the higher the B4C content, the higher the hardness of coatings because the hardness of B4C is higher than that of Al-Si

  17. Laser surface treatment of aluminum based composite mixed with B4C particles

    Yilbas, B. S.; Karatas, C.; Karakoc, Halil; Abdul Aleem, B. J.; Khan, S.; Al-Aqeeli, N.

    2015-03-01

    Laser treatment of hot pressed mixture of aluminum (85 wt%) and B4C (15 wt%) is carried out. Metallurgical and morphological changes at the laser treated surface are examined using the analytical tools. Microhardness and fracture toughness of the workpiece surfaces are determined prior to and after the laser treatment process. Texture and hydrophobicity of the laser treated surface is assessed incorporating the atomic force microscopy and contact angle measurements. It is found that a dense layer consisting of fine grains of sub-micron sizes (0.8-0.4 μm) and B4C particles is formed at the laser treated surface. Microhardness increases at the laser treated surface because of the presence of the dense layer and the formation of AlN compounds at the surface. Fracture toughness of the laser treated surface reduces slightly because of the microhardness enhancement at the surface. The textures of the laser treated surface compose of micro/nano poles, which result in higher contact angles than that of the untreated surface, and formation of AlN compound adds to the surface hydrophobicity enhancements.

  18. The asymmetric radio structure and record jet of giant quasar 4C34.47

    Hocuk, S

    2010-01-01

    Giant double-lobed radio source 4C34.47 displays a straight one-sided jet, measuring a record length of 380kpc, in its double-lobed radio structure. Assuming an intrinsically symmetric two-sided jet structure the radio source jet axis must be at least 33 degrees away from the sky plane, that is within 57 degrees from the line of sight. The radio polarization properties indicate that this giant source has largely outgrown the depolarizing halo generally associated with the host galaxies of powerful radio sources. The measured small depolarization asymmetry is nevertheless in accordance with its inferred orientation. All data for this giant radio source are in agreement with its preferred orientation as predicted within the unification scheme for powerful radio sources. Seen under a small aspect angle the radio source is large but not excessively large. The global properties of 4C34.47 do not differ from other giant (old) FR2 radio sources: it is a slowly expanding low-luminosity radio source.

  19. Multifrequency Studies of the Peculiar Quasar 4C +21.35 During the 2010 Flaring Activity

    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...

  20. On the Merging Cluster Abell 578 and Its Central Radio Galaxy 4C +67.13

    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...

  1. A group of neutronics calculations in the MNSR using the MCNP-4C code

    The MCNP-4C code was used to model the 3-D core configuration for the Syrian Miniature Neutron Source Reactor (MNSR). The continuous energy neutron cross sections were evaluated from ENDF/B-VI library to calculate the thermal and fast neutron fluxes in the MNSR inner and outer irradiation sites. The thermal fluxes in the MNSR inner irradiation sites were measured for the first time using the multiple foil activation method. Good agreements were noticed between the calculated and measured results. This model is used as well to calculate neutron flux spectrum in the reactor inner and outer irradiation sites and the reactor thermal power. Three 3-D neutronic models for the Syrian MNSR reactor using the MCNP-4C code were developed also to assess the possibility of fuel conversion from 89.87 % HEU fuel (UAl4-Al) to 19.75 % LEU fuel (UO2). This model is used in this paper to calculate the following reactor core physics parameters: clean cold core excess reactivity, calibration of the control rod worth and calculation its shut down margin, calibration of the top beryllium shim plate reflector, axial neutron flux distributions in the inner and outer irradiation sites and the kinetics parameters ( ιp l and βeff). (authors)

  2. Molecular dynamics simulation of nanoindentation of Fe3C and Fe4C

    Study of nanomechanical response of iron carbides is important because presence of iron carbides greatly influences the performance and longevity of steel components. This work contributes to the literature by exploring nanoindentation of Fe3C and tetrahedral-Fe4C using molecular dynamics simulation. The chemical interactions of iron and carbon were described through an analytical bond order inter-atomic potential (ABOP) energy function. The indentations were performed at an indentation speed of 50 m/s and a repeat trial was performed at 5 m/s. Load–displacement (P–h) curve for both these carbides showed residual indentation depth and maximum indentation depth (hf/hmax) ratio to be higher than 0.7 i.e. a circumstance where Oliver and Pharr method was not appropriate to be applied to evaluate the material properties. Alternate evaluation revealed Fe3C to be much harder than Fe4C. Gibbs free energy of formation and radial distribution function, coupled with state of the average local temperature and von Mises stresses indicate the formation of a new phase of iron-carbide. Formation of this newer phase was found to be due to deviatoric strain rather than the high temperature induced in the substrate during nanoindentation

  3. Thermally induced interface changes in W/B{sub 4}C multilayers

    Rao, P.N., E-mail: pnrao@rrcat.gov.in; Rai, S.K.; Sinha, A.K.; Singh, M.N.; Lodha, G.S.

    2015-08-31

    Multilayer period thickness changes for various thickness ratios, Γ (ratio of W layer thickness to period thickness) as a function of annealing temperatures were studied by grazing incidence X-ray reflectivity (GIXRR), and grazing incidence X-ray diffraction (GIXRD). Both period thickness expansion and compression were observed depending upon Γ and annealing temperatures. Multilayer with the W layer thickness close to the B{sub 4}C layer has undergone less period thickness changes. Successive appearance and disappearance of multilayer Bragg maxima in GIXRR were observed. Such behavior suggested that redistribution of atomic density within bilayer, the displacement of interface and the multilayer period thickness change as annealing proceeds. GIXRD measurements performed using synchrotron radiation suggested the formation of phases corresponding to tungsten boride and carbide. - Highlights: • We reported the influence of the layer thickness on thermal stability of W/B{sub 4}C multilayers. • Depending on the layer thickness ratio, the period variation can be positive or negative. • Diffusion induced structural changes can be minimized by optimizing layers thickness ratio. • Tungsten carbide and boride phases observed at elevated temperatures.

  4. Inflation and monopoles in supersymmetric SU(4)c x SU(2)L x SU(2)R

    We show how hybrid inflation can be successfully realized in a supersymmetric model with gauge group GPS = SU(4)c x SU(2)L x SU(2)R. By including a non-renormalizable superpotential term, we generate an inflationary valley along which GPS is broken to the standard model gauge group. Thus, catastrophic production of the doubly charged magnetic monopoles, which are predicted by the model, cannot occur at the end of inflation. The results of the cosmic background explorer can be reproduced with natural values (of order 10-3) of the relevant coupling constant, and symmetry breaking scale of GPS close to 1016 GeV. The spectral index of density perturbations lies between unity and 0.94. Moreover, the μ-term is generated via a Peccei-Quinn symmetry and proton is practically stable. Baryogenesis in the universe takes place via leptogenesis. The low deuterium abundance constraint on the baryon asymmetry, the gravitino limit on the reheat temperature and the requirement of almost maximal νμ - ντ mixing from SuperKamiokande can be simultaneously met with mνμ, mντ and heaviest Dirac neutrino mass determined from the large angle MSW resolution of the solar neutrino problem, the SuperKamiokande results and SU(4)c symmetry respectively. (author)

  5. Helium bubble evolution in ion irradiated Al/B4C metal matrix composite

    Graphical abstract: Scheme of combined irradiation includes a pre-implantation of 400 keV He+ to 1.0 × 1016 ions/cm2 followed by a 1.5 MeV proton irradiation to 2.2 × 1019 ions/cm2 on the perpendicular surface. TEM samples were prepared by FIB. The area suffered with both He+ pre-implantation and proton irradiation was marked as light blue. - Abstract: Helium behavior in Al/B4C metal matrix composite with two different sets of ion irradiation conditions has been investigated by transmission electron microscopy. Helium bubbles in Al were found to be much larger than those in B4C after a helium fluence of 1.5 × 1017 ions/cm2 at the room temperature. Also, bubbles at grain boundaries and their vicinity in aluminum are faceted. With additional proton irradiation, a bubble denuded zone along the aluminum grain boundary appears. The results are discussed in terms of the energetics of the material system

  6. Consolidation of B4C-TaB2 eutectic composites by spark plasma sintering

    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.

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

    Camacho, I.; Garcia, M.; Herrero, A.; Simón-Díaz, S.

    2016-01-01

    Context. Massive stars play an important role in the chemical and dynamical evolution of the Universe. The first metal-poor stars may have started the reionization of the Universe. To understand these early epochs it is necessary to know the behavior and the physical properties of massive stars in very metal-poor environments. We focus on the massive stellar content of the metal-poor irregular galaxy Sextans A. Aims: Our aim is to find and classify OB stars in Sextans A, so as to later determine accurate stellar parameters of these blue massive stars in this low-metallicity region (Z ~ 0.1 Z⊙). Methods: 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 ~ 1000) GTC-OSIRIS spectra for a fraction of them and carried out spectral classification. For the confirmed O-stars, we derived preliminary stellar parameters. Results: 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 sub-SMC temperature scale. Two of the O-stars are consistent with relatively strong winds and enhanced helium abundances, although results are not conclusive. We discuss the position of the OB stars in the HRD. Initial stellar masses run from slightly below 20 up to 40 solar masses. Conclusions: The target selection method worked well for Sextans A. The stellar temperatures are consistent with findings in other galaxies. Some of the targets deserve follow-up spectroscopy because of indications of a runaway nature, an enhanced helium abundance

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

    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

  9. Grain refinement of AZ91D magnesium alloy by a new Mg–50%Al4C3 master alloy

    A novel and simple method for preparing Mg–50%Al4C3 (hereafter in wt.%) master alloy has been developed by powder in-situ synthesis process under argon atmosphere. X-ray diffraction (XRD), scanning electron microscope (SEM) and energy dispersive X-ray spectroscopy (EDS) results show the existence of Al4C3 particles in this master alloy. After adding 1.8% Mg–50%Al4C3 master alloy, the average grain size of α-Mg decreased from 360 μm to 154 μm. Based on the DTA test results and calculation of the planar disregistry between Al4C3 and α-Mg, Al4C3 particles located in the central regions of magnesium grains can act as the heterogeneous nucleus of primary α-Mg phase

  10. Multifrequency Studies of the Peculiar Quasar 4C +21.35 during the 2010 Flaring Activity

    Ackermann, M.; Ajello, 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.; Knödlseder, 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, Ł.; 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.; Fermi Large Area Telescope Collaboration; Aleksić, J.; Ansoldi, S.; Antonelli, L. A.; Antoranz, P.; Babic, A.; Bangale, P.; Barres de Almeida, U.; Barrio, J. A.; Becerra González, J.; 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.; Carreto Fidalgo, D.; 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.; Delgado Mendez, C.; Doert, M.; Domínguez, A.; Dominis Prester, D.; Dorner, D.; Doro, M.; Einecke, S.; Eisenacher, D.; Elsaesser, D.; Farina, E.; Ferenc, D.; Fonseca, M. V.; Font, L.; Frantzen, K.; Fruck, C.; García López, R. J.; Garczarczyk, M.; Garrido Terrats, D.; Gaug, M.; Giavitto, G.; Godinović, N.; González Muñoz, A.; 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.; López, M.; López-Coto, R.; López-Oramas, A.; Lorenz, E.; Lozano, I.; Makariev, M.; Mallot, K.; Maneva, G.; Mankuzhiyil, N.; Mannheim, K.; Maraschi, L.; Marcote, B.; Mariotti, M.; Martínez, 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.; Prada Moroni, P. G.; Prandini, E.; Preziuso, S.; Puljak, I.; Reinthal, R.; Rhode, W.; Ribó, M.; Rico, J.; Rodriguez Garcia, J.; Rügamer, S.; Saggion, A.; Saito, T.; Saito, K.; Salvati, M.; Satalecka, K.; Scalzotto, V.; Scapin, V.; Schultz, C.; Schweizer, T.; Shore, S. N.; Sillanpää, A.; Sitarek, J.; Snidaric, I.; Sobczynska, D.; Spanier, F.; Stamatescu, V.; Stamerra, A.; Steinbring, T.; Storz, J.; Sun, S.; Surić, T.; Takalo, L.; Takami, H.; Tavecchio, F.; Temnikov, P.; Terzić, T.; Tescaro, D.; Teshima, M.; Thaele, J.; Tibolla, O.; Toyama, T.; Treves, A.; Vogler, P.; Wagner, R. M.; Zandanel, F.; Zanin, R.; MAGIC Collaboration; 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.; Lähteenmäki, A.; Larionov, V. M.; Lister, M. L.; Nieppola, E.; Nikolashvili, M. G.; Ros, E.; Savolainen, T.; Sigua, L. A.; Tornikoski, M.

    2014-05-01

    The discovery of rapidly variable Very High Energy (VHE; E > 100 GeV) γ-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) γ-rays, poses intriguing questions on the location of the γ-ray emitting region in this flat spectrum radio quasar. 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 γ-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 γ-ray peaks, while no clear connection was observed between the X-ray and γ-ray emission. An increasing flux density was observed in radio and mm bands from the beginning of 2009, in accordance with the increasing γ-ray activity observed by Fermi-LAT, and peaking on 2011 January 27 in the mm regime (230 GHz). We model the spectral energy distributions (SEDs) of 4C +21.35 for the two periods of the VHE detection and a quiescent state, using a one-zone model with the emission coming from a very compact region outside the broad line region. The three SEDs can be fit with a combination of synchrotron self-Compton and external Compton emission of seed photons from a dust torus, changing only the electron distribution parameters between the epochs. The fit of the optical/UV part of the spectrum for 2010 April 29 seems to favor an inner disk radius of

  11. On the Merging Cluster Abell 578 and Its Central Radio Galaxy 4C+67.13

    Hagino, K.; Stawarz, Ł.; Siemiginowska, A.; Cheung, C. C.; Kozieł-Wierzbowska, D.; Szostek, A.; Madejski, G.; Harris, D. E.; Simionescu, A.; Takahashi, T.

    2015-06-01

    Here we analyze radio, optical, and X-ray data for the peculiar cluster Abell 578. This cluster is not fully relaxed and consists of two merging sub-systems. The brightest cluster galaxy (BCG), CGPG 0719.8+6704, is a pair of interacting ellipticals with projected separation ˜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 ˜ {{10}-4} (for the estimated black hole masses of ˜ 3× {{10}8} {{M}⊙ } and ˜ {{10}9} {{M}⊙ }). The gathered X-ray (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 (˜60 kpc projected) between the position of the BCG and the cluster center inferred from the modeling of the X-ray surface brightness distribution. Detailed analysis of the brightness profiles and temperature revealed also that the cluster gas in the vicinity of 4C+67.13 is compressed (by a factor of about ˜1.4) and heated (from ≃ 2.0 keV up to 2.7 keV), consistent with the presence of a weak shock (Mach number ˜1.3) driven by the expanding jet cocoon. This would then require the jet kinetic power of the order of ˜ {{10}45} erg s-1, implying either a very high efficiency of the jet production for the current accretion rate, or a highly modulated jet/accretion activity in the system. Based on service observations made with the WHT operated on the island of La Palma by the Isaac Newton Group in the Spanish Observatorio del Roque de los Muchachos of the Instituto de Astrofísica de Canarias.

  12. Green tea extract protects against nonalcoholic steatohepatitis in ob/ob mice by decreasing oxidative and nitrative stress responses induced by proinflammatory enzymes.

    Chung, Min-Yu; Park, Hea Jin; Manautou, Jose E; Koo, Sung I; Bruno, Richard S

    2012-04-01

    Oxidative and nitrative stress responses resulting from inflammation exacerbate liver injury associated with nonalcoholic steatohepatitis (NASH) by inducing lipid peroxidation and protein nitration. The objective of this study was to investigate whether the anti-inflammatory properties of green tea extract (GTE) would protect against NASH by suppressing oxidative and nitrative damage mediated by proinflammatory enzymes. Obese mice (ob/ob) and their 5-week-old C57BL6 lean littermates were fed 0%, 0.5% or 1% GTE for 6 weeks (n=12-13 mice/group). In obese mice, hepatic lipid accumulation, inflammatory infiltrates and serum alanine aminotransferase activity were markedly increased, whereas these markers of hepatic steatosis, inflammation and injury were significantly reduced among obese mice fed GTE. GTE also normalized hepatic 4-hydroxynonenal and 3-nitro-tyrosine (N-Tyr) concentrations to those observed in lean controls. These oxidative and nitrative damage markers were correlated with alanine aminotransferase (P<.05; r=0.410-0.471). Improvements in oxidative and nitrative damage by GTE were also associated with lower hepatic nicotinamide adenine dinucleotide phosphate oxidase activity. Likewise, GTE reduced protein expression levels of hepatic myeloperoxidase and inducible nitric oxide synthase and decreased the concentrations of nitric oxide metabolites. Correlative relationships between nicotinamide adenine dinucleotide phosphate oxidase and hepatic 4-hydroxynonenal (r=0.364) as well as nitric oxide metabolites and N-Tyr (r=0.598) suggest that GTE mitigates lipid peroxidation and protein nitration by suppressing the generation of reactive oxygen and nitrogen species. Further study is warranted to determine whether GTE can be recommended as an effective dietary strategy to reduce the risk of obesity-triggered NASH. PMID:21543212

  13. Influence of graphite on the hardness and wear behavior of AA6061-B4C composite: Vpliv grafita na trdoto in vedenje kompozita AA6061-B4C pri obrabi:

    Chandramohan, Govindarajulu; Prabagaran, Subramaniam; Shanmughasundaram, Palanisamy

    2014-01-01

    Dry-sliding-wear behavior of AA6061, AA6061-B4C composite and AA6061-B4C-Gr hybrid composite was investigated by employing a pin-on-disc wear-test rig. Hardness tests were also carried out. Graphite was used as a solid lubricant since it is a soft, slippery and greyish-black substance. Because of the cleavage (crystal) loose interlamellar coupling, graphite has good lubricating properties. A comparative analysis was made on the hardness and wear behavior of AA6061, AA6061-B4C composite and AA...

  14. Microstructural development of B{sub 4}C-TiB{sub 2} composites by in situ reacting titanium with B{sub 4}C in the hot-press

    Pekin, S.; Zangvil, A.; Duemler, I. [Univ. of Illinois, Urbana-Champaign, IL (United States)

    1996-12-31

    Boron carbide-titanium diboride composites containing graphite have been prepared by in situ reaction of Ti and B{sub 4}C in the hot-press. Infiltration of initially spherical titanium particles into the B{sub 4}C matrix upon melting resulted in formation of TiB{sub 2} regions in the shape of hollow ellipsoids when the Ti particle size was much greater than the B{sub 4}C particle size. It was shown that these hollow ellipsoids could be broken by the uniaxial pressure to yield a composite with a modified microstructure.

  15. Inhibition of Leptin-ObR Interaction Does not Prevent Leptin Translocation Across a Human Blood-Brain Barrier Model.

    Gonzalez-Carter, D; Goode, A E; Fiammengo, R; Dunlop, I E; Dexter, D T; Porter, A E

    2016-06-01

    The adipocyte-derived hormone leptin regulates appetite and energy homeostasis through the activation of leptin receptors (ObR) on hypothalamic neurones; hence, leptin must be transported through the blood-brain barrier (BBB) to reach its target sites in the central nervous system. During obesity, however, leptin BBB transport is decreased, in part precluding leptin as a viable clinical therapy against obesity. Although the short isoform of the ObR (ObRa) has been implicated in the transport of leptin across the BBB as a result of its elevated expression in cerebral microvessels, accumulating evidence indicates that leptin BBB transport is independent of ObRa. In the present study, we employed an ObR-neutralising antibody (9F8) to directly examine the involvement of endothelial ObR in leptin transport across an in vitro human BBB model composed of the human endothelial cell line hCMEC/D3. Our results indicate that, although leptin transport across the endothelial monolayer was nonparacellular, and energy- and endocytosis-dependent, it was not inhibited by pre-treatment with 9F8, despite the ability of the latter to recognise hCMEC/D3-expressed ObR, prevent leptin-ObR binding and inhibit leptin-induced signal transducer and activator of transcription 3 (STAT-3) phosphorylation in hCMEC/D3 cells. Furthermore, hCMEC/D3 cells expressed the transporter protein low-density lipoprotein receptor-related protein-2 (LRP-2), which is capable of binding and endocytosing leptin. In conclusion, our results demonstrate that leptin binding to and signalling through ObR is not required for efficient transport across human endothelial monolayers, indicating that ObR is not the primary leptin transporter at the human BBB, a role which may fall upon LRP-2. A deeper understanding of leptin BBB transport will help clarify the exact causes for leptin resistance seen in obesity and aid in the development of more efficient BBB-penetrating leptin analogues. PMID:27037668

  16. B4C solid target boronization of the MST reversed-field pinch

    A solid rod of hot-pressed boron carbide is being used as the source of boron during boronization of MST. The most striking result of this procedure is the reduction in oxygen contamination of the plasma (O III radiation, characteristic of oxygen at the edge, falls by about a factor of 3 after boronization.). The radiated power fraction drops to about half its initial value. Particle reflux from the wall is also lowered, making density control simpler. The rod (12.7 mm diameter) is inserted into the edge plasma of normal high-power RFP discharges. B4C is ablated from the surface of the rod and deposited in a thin film (a-B/C:H) on the walls and limiters. The energy flux carried by ''superthermal'' (not ''runaway'') electrons at the edge of MST appears to enhance the efficient, non-destructive ablation of the boron carbide rod

  17. Distorted structure in the small high-redshift radio source 4C 29.50

    The powerful radio source 4C 29.50, which is identified with a quasar at redshift 1.927, has been mapped with a variety of instruments, frequencies, and resolutions. The highest resolution is 30 mas, corresponding to about 150 pc at this redshift. The projected overall dimensions of the radio source are subgalactic, and the structure is very distorted. There are apparent sudden deflections of a jet emerging from the quasar core, and it is proposed that these are due to interaction with a dense, clumpy interstellar eenvironment. The great power of the source and the small scales on which the deflections occur yield constraints on the properties of this environment. 31 references

  18. Oxidation of B4C by steam at high temperatures: New experiments and modelling

    The oxidation kinetics of various types of boron carbides (pellets, powder) were investigated in the temperature range between 1073 and 1873 K. Oxidation rates were measured in transient and isothermal tests by means of mass spectrometric gas analysis. It was found that oxidation is strongly influenced by the thermohydraulic boundary conditions and in particular by the steam partial pressure and flow rate. On the other hand, the microstructure of the B4C samples has a limited influence on oxidation. Very low amounts of methane were produced in these tests. On the basis of the experimental data obtained in the isothermal tests, a new model on boron carbide oxidation was developed. The model self-consistently simulates surface reaction kinetics and mass transport of various species in the multi-component gas phase as rate determining steps of the oxidation process. The model was implemented in the SVECHA/QUENCH code and verified against the transient tests

  19. Revisiting the electrochemical impedance behaviour of the LiFePO4/C cathode

    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.

  20. Processing and characterization of B4C-SiC-Si-TiB2 composites

    B4C-SiC-Si-TiB2 composites were synthesized by a two step process. TiB2 particles in the size range 2-5 μm were generated in situ in the first step and were distributed in the residual silicon present in the reaction bonded boron carbide, in the second step. The composites were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), electron probe micro analysis (EPMA) and micro-hardness testing. The density and average hardness of siliconized boron carbide samples with and without TiB2 particle reinforcement were found to be 2.67 g/cm3 and 25 GPa and 2.54 g/cm3 and 21 GPa, respectively.

  1. TEM characterization of La/B4C multilayer systems by the geometric phase method

    New La/B4C multilayer systems with layer thicknesses in the nanometer range have been deposited onto structured silicon (001) surfaces by magnetron sputtering and have been characterized by transmission electron microscopy (TEM). By applying a geometric phase method which has been originally developed for measuring displacement fields from high-resolution TEM images, we demonstrate that the structural perfection of multilayers, especially their local layer periods and local layer orientations, can be analyzed with high sensitivity from bright-field TEM images of cross-section specimens. The determination of these structure parameters is relevant for the assessment of the reflectivity properties of such multilayer systems in advanced X-ray optical components. (copyright 2005 WILEY-VCH Verlag GmbH and Co. KGaA, Weinheim) (orig.)

  2. DNA level in guard cells nuclei of Ornithogalum umbellatum ovary is 2C-4C

    Maria Kwiatkowska

    2011-04-01

    Full Text Available The DNA content after Feulgen reaction in the guard cells and epidermis of Omithogalum umbellatum ovary was cytophotometrically measured in different phases of flower development. Only in bud of flowers guard cells DNA content was 2C while in full blown flowers it was higher, between 2C-4C. This observation was supported by autoradiographic studies with 3H-thymidine which was incorporated into guard cell nuclei in the ovary epidermis of newly developed flowers. Thus DNA level in O. umbellatum guard cells was higher than those in other plants described in literature. On the other hand, DNA content in the epidermis cells increased gradually with ovary growth reaching the maximum level of 8C in some cells.

  3. Simulation of absorbed dose in human blood with MCNP 4C code

    Biological dosimetry, based on the analysis of solid stained dicentric chromosomes, has been used since the mid 1960s. The intervening years have seen great improvements bringing the technique to a point where dicentric analysis has become a routine component of the radiological protection programs of many countries. Experience of its application in thousands of cases of actual or suspected overexposures has proved the worth of the method. The aberrations scored in the lymphocytes are interpreted in terms of absorbed dose by reference to a dose response calibration curve. This curve will have been produced by exposure of blood in vitro to doses of the appropriate quality of radiation. The doses given to the specimens should be traceable via a physical instrument such as an ionization chamber, to a primary or secondary standard. An alternative to obtain the information about absorbed dose in a specific blood volume is through the Monte Carlo method. The use of such technique is worldwide when physical measurements are inconvenient or impossible, and particularly useful for the solution of complex problems that cannot be modeled by codes that use deterministic methods. It is applied to particle systems as neutrons and electrons, as well as photons or still in mixed systems. Due to difficulties that involve the use of neutrons, this technique has shown extreme importance for preliminary research and experimental arrangements with neutron sources. In this study, the main objective was to simulate the dose absorbed by a blood sample in an experimental arrangement through the irradiation with sources of 241AmBe. It was used the code Monte Carlo N-Particle version 4C (MCNP 4C) whose data had been processed parallel in a computational structure in a cluster. This method allowed estimating the absorbed dose in a specific blood volume, making possible the experimental setup arrangement. (author)

  4. Hard X-Ray Detection of the High Redshift Quasar 4C 71.07

    Malizia, A.; Bassani, L.; Dean, A. J.; McCollough, M. L.; Stephen, J. B.; Zhang, S. N.

    1999-01-01

    BATSE/OSSE observations of the high redshift quasar 4C 71.07 indicate that this is the brightest and furthest AGN so far detected 20 keV. BATSE Earth occultation data have been used to search for emission from 4C 71.07 from nearly 3 years of observation. The mean source flux over the- whole period in the BATSE energy range 20-100 keV is (13.2 +/- 1.06) x 10(exp -11) erg/square cm/s corresponding to a luminosity of 2 x 10(exp 48 erg/s. The BATSE light curve over the 3 years of observations shows several flare-like events, one of which (in January 1996) is associated with an optical flare (R=16.1) but with a delay of 55 days. The OSSE/BATSE spectral analysis indicates that the source is characterized by a flat power spectrum (Gamma is approximately 1.1- 1.3) when in a low state: this spectral form is consistent within errors with the ASCA and ROSAT spectra. This means that the power law observed from 0.1 to 10 keV extends up to at least 1 MeV but steepens soon after to meet EGRET high energy data. BATSE data taken around the January 1996 flare suggests that the spectrum could be steeper when the source is in a bright state. The upsilon-F-upsilon representation of the source is typical of a low frequency peaked/ gamma- ray dominated blazar, with the synchrotron peak in the mm-FIR band and the Compton peak in the MeV band. The BATSE and OSSE spectral data seem to favour a model in which the high energy - flux is due to the sum of the synchrotron self-Compton and the external Compton contributions: this is also supported by the- variability behaviour of the source.

  5. Englerin A Agonizes the TRPC4/C5 Cation Channels to Inhibit Tumor Cell Line Proliferation.

    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.

  6. Solubility of alkali metal halides in the ionic liquid [C4C1im][OTf].

    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. PMID:27264676

  7. The Swift Gamma-Ray Burst Host Galaxy Legacy Survey - I. Sample Selection and Redshift Distribution

    Perley, D. A.; Krühler, T.; Schulze, S.; De Ugarte Postigo, A.; Hjorth, J.; Berger, E.; Cenko, S. B.; Chary, R.; Cucchiara, A.; Ellis, R; Fong, W.; Fynbo, J. P. U.; J. Gorosabel; Greiner, J.; Jakobsson, P.

    2015-01-01

    We introduce the Swift Gamma-Ray Burst Host Galaxy Legacy Survey ("SHOALS"), a multi-observatory high-redshift galaxy survey targeting the largest unbiased sample of long-duration gamma-ray burst (GRB) hosts yet assembled (119 in total). We describe the motivations of the survey and the development of our selection criteria, including an assessment of the impact of various observability metrics on the success rate of afterglow-based redshift measurement. We briefly outline our host galaxy obs...

  8. Excellent Temperature Performance of Spherical LiFePO4/C Composites Modified with Composite Carbon and Metal Oxides

    2014-01-01

    Nanosized spherical LiFePO4/C composite was synthesized from nanosized spherical FePO4 ·2H2O, Li2C2O4, aluminum oxide, titanium oxide, oxalic acid, and sucrose by binary sintering process. The phases and morphologies of LiFePO4/C were characterized using SEM, TEM, CV, EIS, EDS, and EDX as well as charging and discharging measurements. The results showed that the as-prepared LiFePO4/C composite with good conductive webs from nanosized spherical FePO4 ·2H2O exhibits excellent electrochemical pe...

  9. Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating

    Jianjun Song; Ying Zhang; Guangjie Shao

    2013-01-01

    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 m...

  10. Model of deformation and fracture of TiB2+B4C based cermet under dynamic loading

    One introduces a mathematical model describing deformation and fracture of titanium diboride and boron carbide base (TiB2+B4C) cermet with a metal binder under impact loading. TiB2+B4C base cermet with a metal binder was prepared by means of self-propagating high-temperature synthesis. In terms of the mentioned model one solved the problem dealing with penetration of TiB2+B4C base cermet into aluminium semi-infinite barrier

  11. CONSTRAINTS ON THE MAGELLANIC CLOUDS' INTERACTION FROM THE DISTRIBUTION OF OB STARS AND THE KINEMATICS OF GIANTS

    Young, OB-type candidates are identified in a ∼7900 deg2 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°-2° 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.

  12. VLBI Measurements of Plasma Turbulence Associated with the Cygnus OB1 Association

    Spangler, Steven R.; Cordes, James M.

    1998-10-01

    We have made dual-frequency (1.67 and 5.00 GHz) VLBI observations of five compact, presumably extragalactic radio sources in the Galactic plane in the constellation of Cygnus. The lines of sight to these sources pass through a part of the interstellar medium that is modified by the Cygnus OB1 association. The VLBI observations were processed to yield measurements of the scattering measure due to interstellar plasma turbulence. The dual-frequency VLBI observations allowed estimates of the possible intrinsic structure contamination of the scattering measurements. Such an error is estimated to be less than 5% of the scattering measure for our two best-observed cases, and 15% to as high as 30% for a more weakly scattered source. Modeling the spatial power spectrum of the turbulence by Pδn(q) = C2Nq-α, where q is the spatial wavenumber of the turbulent fluctuations, our observations provide a measurement of 0LC2Ndz, where L is the thickness of the scattering medium and z is a coordinate along the line of sight. When combined with our earlier observations of the radio source 2013+370, we have a total of six lines of sight through the Cygnus OB1 association. Our observations show that the scattering through the Cygnus OB1 association is heavy and that the scattering measures vary from 0.14 to 2.21 m-20/3 kpc on lines of sight separated by as little as 1°-2°. When combined with measurements of the emission measure in the same directions, our scattering-measure results constrain properties of the turbulence in the Cygnus OB1 association. Specifically, if ε is the normalized amplitude of the density fluctuations, and l0 is the outer scale to the Kolmogorov spectrum, then our combined scattering measure-emission measure data set constrains the quantity ε2/(1+ε2)l2/30. The mean value is ~4.3 × 10-13 cm-2/3, with a range of about 0.5 in the logarithm. We do not have sufficient information to determine ε and l0 separately, but plausible ranges are ε < 1 and l0 < 3 pc

  13. Comparison of microstructural and mechanical properties of Al–TiC, Al–B4C and Al–TiC–B4C composites prepared by casting techniques

    In the present work, production of Al–10%TiC, Al–10% B4C, Al–5%TiC–5%B4C (volume fraction) composites by casting techniques were studied. However, casting techniques suffers from poor incorporation and distribution of the reinforcement particles in the matrix. These problems become especially significant as the reinforcement size decreases due to greater agglomeration tendency and reduced wettability of the particles with the melt. Microstructure characterization of the composite samples was investigated by using scanning electron microscopy (SEM) equipped with energy dispersive spectroscopy (EDS) and X-ray diffractometer (XRD).The results showed heat treatment of B4C particles and addition of TiC particles with the flux improved the wettability and incorporation of reinforcement particles into melt. Mechanical characterization of samples showed that maximum hardness had belonged to Al–5%TiC–5%B4C composite, maximum yield and tensile strength had belonged to Al–10%B4C composite and maximum elongation had belonged to Al–10%TiC composite. Furthermore, wear properties of composites revealed the better behavior for Al–B4C composite.

  14. The INGV's new OBS/H: Analysis of the signals recorded at the Marsili submarine volcano

    D'Alessandro, Antonino; D'Anna, Giuseppe; Luzio, Dario; Mangano, Giorgio

    2009-05-01

    The ocean bottom seismometer with hydrophone deployed on the flat top of the Marsili submarine volcano (790 m deep) by the Gibilmanna OBS Lab (CNT-INGV) from 12th to 21st July, 2006, recorded more than 1000 transient seismic signals. Nineteen of these signals were associated with tectonic earthquakes: 1 teleseismic, 8 regional (located by INGV) and 10 small local seismic events (non located earthquakes). The regional events were used to determine sensor orientation. By comparing the signals recorded with typical volcanic seismic activity, we were able to group all the other signals into three categories: 817 volcano-tectonic type B (VT-B) events, 159 occurrences of high frequency tremor (HFT) and 32 short duration events (SDE). Small-magnitude VT-B swarms, having a frequency band of 2-6 Hz and a mean length of about 30 s, were almost all recorded during the first 7 days. During the last 2 days, the OBS/H mainly recorded HFT events with frequencies of over 40 Hz and of a few minutes in length. Signals that have similar features in frequency and time domain are generally associated with hydrothermal activity. During the last two days a signal was recorded that had a frequency content similar to that of VT-B events was recorded. It will be referred to as continuous volcanic tremor (CVT). The SDE signals, characterized by a quasi-monochromatic waveform and having an exponential decaying envelope, may have been generated by oscillations of resonant bodies excited by magmatic or hydrothermal activity. By applying polarization and parametric spectral analyses, we inferred that the VT-B were probably multi P-phase events having shallow sources that were situated in narrow azimuthal windows in relation to the positions of the OBS/H. The parametric spectral analysis of the SDE signals allowed us to determine their dominant complex frequencies with high accuracy; these frequencies are distributed in two distinct clusters on the complex plane.

  15. OPTICAL PHOTOMETRIC GTC/OSIRIS OBSERVATIONS OF THE YOUNG MASSIVE ASSOCIATION CYGNUS OB2

    In order to fully understand the gravitational collapse of molecular clouds, the star formation process, and the evolution of circumstellar disks, these phenomena must be studied in different Galactic environments with a range of stellar contents and positions in the Galaxy. The young massive association Cygnus OB2, in the Cygnus-X region, is a unique target to study how star formation and the evolution of circumstellar disks proceed in the presence of a large number of massive stars. We present a catalog obtained with recent optical observations in the r, i, z filters with OSIRIS, mounted on the 10.4 m Gran Telescopio CANARIAS telescope, which is the deepest optical catalog of Cyg OB2 to date. The catalog consists of 64,157 sources down to M = 0.15 M☉ at the adopted distance and age of Cyg OB2. A total of 38,300 sources have good photometry in all three bands. We combined the optical catalog with existing X-ray data of this region, in order to define the cluster locus in the optical diagrams. The cluster locus in the r – i versus i – z diagram is compatible with an extinction of the optically selected cluster members in the 2.64m V m range. We derive an extinction map of the region, finding a median value of AV = 4.33m in the center of the association, decreasing toward the northwest. In the color-magnitude diagrams, the shape of the distribution of main-sequence stars is compatible with the presence of an obscuring cloud in the foreground ∼850 ± 25 pc from the Sun.

  16. Winds of low-metallicity OB-type stars: HST-COS spectroscopy in IC 1613

    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.

  17. Perception oro-sensorielle des lipides alimentaires et obésité

    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.

  18. ObsPy: A Python toolbox for seismology - Current state, applications, and ecosystem around it

    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.

  19. Semantic and grammatical features of o-/ob- in verbs of emotion in Slovene

    Będkowska-Kopczyk, Agnieszka

    2012-01-01

    This paper examines how the prefix o-/ob- reflects the spatial bases of emotion events that comprise emotion scripts in Slovene. It is suggested that the prefix and emotion predicates form constructions. It is shown that the spatially based metaphorical meaning of the prefix in verbs of emotion blends with the prefix’s temporal meaning (i.e., inchoative, resultative, and factitive). Thus, the prefix “cooperates” with the meanings of the emotion predicates in terms of the spatial and temporal ...

  20. DOSTOJANSTVO BOLNIKA OB KONCU ŽIVLJENJA: PRAVNI VIDIKI IN ETIČNE DILEME

    Ham Kacin, Klavdija

    2013-01-01

    Medicinske sestre imajo pomembno nalogo za ohranjanje dostojanstva pri pacientih v zadnjih dneh življenja in za njihovo dostojanstveno smrt. Za ohranjanje dostojanstva neozdravljivo bolnega in umirajočega pacienta naj bi zdravstvena nega zajemala širok spekter aktivnosti, ki vplivajo na odpravo ali zmanjšanje dejavnikov, ki lahko zmanjšajo pacientov občutek dostojanstva. Za uspešno ohranjanje dostojanstva je pomembno dobro poznavanje pravnih vidikov, pravic pacientov v zadnjem obdobju življen...

  1. Cyg OB2 #5: When three stars are just not enough

    Kennedy, M; Dougherty, S. M.; P.M. Williams; Fink, A.

    2010-01-01

    Archival observations from the Very Large Array (VLA) at frequencies between 1.4 GHz and 43 GHz of the 6.6-day O6.5-7+O5.5-6 binary Cyg OB2 #5 over 20 years are re-examined. The aim is to determine the location and character of its known variable radio emission. The radio emission consists of a primary component associated with the binary, and a non-thermal source (NE), $0.8" to the NE. This work reveals that NE shows no evidence of variation demonstrating that the variable emission arises in...

  2. Modelling the radio emission from Cyg OB2 #5: a quadruple system?

    Kennedy, M; Dougherty, S. M.; P.M. Williams; Fink, A.

    2009-01-01

    Fifty archival radio observations of the supergiant binary Cyg OB2 #5 using the Very Large Array over 20 years are re-examined to determine the location and character of the previously detected variable radio emission. The radio emission from the system consists of a primary component that is associated with the binary, and a non-thermal source (NE) that has been ascribed to a wind-collision region (WCR) between the stellar winds of the binary and that of a B-type star (Star D) to the NE. NE ...

  3. KARIERNE ZMOŽNOSTI MLADEGA DIPLOMANTA OB VSTOPU NA TRG DELA V 21. STOLETJU

    Šalamun, Nina

    2016-01-01

    V diplomskem delu smo skušali prikazati karierne zmožnosti mladih diplomantov ob vstopu na trg dela v 21. stoletju. Opisali smo teoretična spoznanja o karieri in kako so se ta spreminjala skozi zgodovino. Izpostavili smo teorijo kariernih sider, ki jo teoretiki ocenjujejo za najbolj celovito, in opisali nove vzorce karier, ki so se pojavili zaradi tržnih in ekonomskih sprememb. Prikazali smo, kakšna znanja in kompetence so potrebni današnjim diplomantom na trgu delovne sile in kakšen j...

  4. SISTEMIZACIJA DELOVNIH MEST V PODJETJU VIGIT D.O.O. ZAGORJE OB SAVI

    Podlesnik, Dunja

    2010-01-01

    V Zakonu o delovnih razmerjih je določeno, da mora delodajalec s splošnim aktom določiti pogoje za opravljanje dela na posameznem delovnem mestu oziroma za vrsto dela. Ta obveznost se sicer ne nanaša na manjše delodajalce, vendar smo se v podjetju Vigit d.o.o. Zagorje ob Savi odločili, da pripravimo učinkovit in pregleden pravilnik o organizaciji in sistemizaciji delovnih mest. Menimo namreč, da bo to prispevalo k boljšemu delu na kadrovskem področju in nasploh k doseganju poslovnih cilj...

  5. Non-LTE Abundances of Magnesium, Aluminum and Sulfur in OB Stars Near the Solar Circle

    Daflon, S.; Cunha, K.; Smith, V.V.; Butler, K.

    2002-01-01

    Non-LTE abundances of magnesium, aluminum and sulfur are derived for a sample of 23 low-v \\sin i stars belonging to six northern OB associations of the Galactic disk within 1 kpc of the Sun. The abundances are obtained from the fitting of synthetic line profiles to high resolution spectra. A comparison of our results with HII region abundances indicates good agreement for sulfur while the cepheid abundances are higher. The derived abundances of Mg show good overlap with the cepheid results. T...

  6. Posredovanje gasilcev ob ekološki nesreči

    Erjavec, Gregor

    2016-01-01

    Slovenija je zaradi svoje geografske lege izpostavljena številnim naravnim in drugim nesrečam. Zaradi vse večjega in hitrejšega razvoja tehnologije in industrializacije se na svetu pojavljajo nove oblike nevarnih snovi, ki ob nenadzorovanem transportu, skladiščenju ali uporabi povzročijo t. i. ekološko nesrečo, ki ima lahko tudi katastrofalne posledice. Slovenija ima za varstvo pred nesrečami vzpostavljeno Upravo Republike Slovenije za zaščito in reševanje, ki razpolaga z ogromno enotami, ki ...

  7. Nature vs. Nurture: The influence of OB star environments on proto-planetary disk evolution

    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.

  8. Processing and characterization of B4C/Cu graded composite as plasma facing component for fusion reactors

    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.

  9. Electronic structure and electrical transport characteristics of C60, 2C60 and 4C60 fullerene molecules

    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.

  10. Pressure mediated hypertrophy and mechanical stretch up-regulate expression of the long form of leptin receptor (ob-Rb in rat cardiac myocytes

    Matsui Hiroki

    2012-12-01

    Full Text Available Abstract Background Hyperleptinemia is known to participate in cardiac hypertrophy and hypertension, but the relationship between pressure overload and leptin is poorly understood. We therefore examined the expression of leptin (ob and the leptin receptor (ob-R in the pressure-overloaded rat heart. We also examined gene expressions in culture cardiac myocytes to clarify which hypertension-related stimulus induces these genes. Results Pressure overload was produced by ligation of the rat abdominal aorta, and ob and ob-R isoform mRNAs were measured using a real-time polymerase chain reaction (PCR. We also measured these gene expressions in neonatal rat cardiac myocytes treated with angiotensin II (ANGII, endothelin-1 (ET-1, or cyclic mechanical stretch. Leptin and the long form of the leptin receptor (ob-Rb gene were significantly increased 4 weeks after banding, but expression of the short form of the leptin receptor (ob-Ra was unchanged. ob-Rb protein expression was also detected by immunohistochemistry in hypertrophied cardiac myocytes after banding. Meanwhile, plasma leptin concentrations were not different between the control and banding groups. In cultured myocytes, ANGII and ET-1 increased only ob mRNA expression. However, mechanical stretch activated both ob and ob-Rb mRNA expression in a time-dependent manner, but ob-Ra mRNA was unchanged by any stress. Conclusions We first demonstrated that both pressure mediated hypertrophy and mechanical stretch up-regulate ob-Rb gene expression in heart and cardiac myocytes, which are thought to be important for leptin action in cardiac myocytes. These results suggest a new local mechanism by which leptin affects cardiac remodeling in pressure-overloaded hearts.

  11. Kinetic Behavior of LiFePO4/C Thin Film Cathode Material for Lithium-Ion Batteries

    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.

  12. Fabrication of Al5083/B4C surface composite by friction stir processing and its tribological characterization

    Narayana Yuvaraj; Sivanandam Aravindan; Vipin

    2015-01-01

    Improved surface properties with the retainment of bulk properties are necessary for a component for enhanced wear characteristics. Friction stir processing (FSP) is used to produce such surface composites. Fabrication of 5083 aluminum alloy with reinforced layers of boron carbide (B4C) through FSP was carried out. Micro and nano sized B4C particles were used as reinforcements. The friction processed surface composite layer was analyzed through optical and scanning electron microscopical stud...

  13. Solvothermal synthesis and electrochemical performance of Li2MnSiO4/C cathode materials for lithium ion batteries

    Highlights: • Li2MnSiO4/C nanocomposite has been synthesized by the solvothermal method. • The particles of Li2MnSiO4/C are much smaller and more uniform. • The presence of Ni improves discharge capacity of Li2MnSiO4/C cathode material. • The initial discharge capacity of Ni-modified Li2MnSiO4/C is 274.5 mAh g−1 at 25 °C. - Abstract: Orthorhombic structure Li2MnSiO4/C with Pmn21 space group is synthesized by the solvothermal method. Carbon coating and Ni2+ doping are used to improve the electronic conductivity and the cycling performance of Li2MnSiO4 cathode material, respectively. The particles of Li2MnSiO4/C are much smaller and more uniform than those of Li2MnSiO4 due to the carbon coating. It is shown that Ni2+ has been reduced into metal Ni during the synthesis process. The synthesized Ni-modified Li2MnSiO4/C (denoted as (LMS@Ni)/C) cathode material exhibits better electrochemical performance in comparison with Li2MnSiO4/C, attributing to higher lithium ion diffusion coefficient as well as electronic conductivity. The initial discharge capacity of (LMS@Ni)/C is 274.5 mA h g−1 and the reversible capacity after 20 cycles is 119.8 mA h g−1 at 25 °C

  14. Electrochemical properties of Li2 FeSiO4 /C nanocomposites prepared by sol-gel and hydrothermal methods

    Kumar, Ajay; Jayakumar, O. D.; Naik, Vaman M.; Nazri, Gholam A.; Naik, Ratna

    Li2FeSiO4 is considered as potential cathode material for next generation lithium ion batteries because of its high specific theoretical capacity, low cost, and safety. However, it suffers from poor electronic conductivity and slow lithium ion diffusion in the solid phase. To address these issues, we have studied mesoporous Li2FeSiO4/C composites synthesized by sol-gel (SG) and hydrothermal (HT) methods using tri-block copolymer (P123) as carbon source and structure directing agent. The structure and morphology of the composites were characterized by XRD, SEM and TEM and the surface area and pore size distribution were measured by using N2 adsorption/desorption. Galvanostatic cycling, electrochemical impedance spectroscopy, and cyclic voltammetry were used to evaluate the electrochemical performance of the Li2FeSiO4/C composites. The Li2FeSiO4/C (HT) composites show a superior electrochemical performance compared to Li2FeSiO4/C (SG). At C/30 rate, the discharge capacity of Li2FeSiO4/C (HT) reached ~276 mAh/g in the 1.5-4.6 V window and shows better rate capability and stability at high rates. We attribute the improved electrochemical performance of Li2FeSiO4/C (HT) to its large surface area and reduced particle size. The details of the study will be presented.

  15. Thermal stability studies of ion beam sputter deposited C/B4C X-ray multilayer mirror

    We report the results of thermal stability study carried out on C/B4C multilayer structure. We have analyzed the structure of as-deposited and vacuum annealed C/B4C multilayer film by soft X-ray reflectivity measurements. We observed that multilayer period expansion continues till 600 °C and slight contraction at higher annealing temperature. The results show that the multilayer structure is stable even after 700 °C annealing. Raman spectroscopy indicates graphitization of carbon layer with increasing annealing temperature. Graphitization of carbon results in increases of layer thickness and decreases in density as also observed by soft X-ray reflectivity. We observed reduction in measured soft X-ray reflectivity at 6.56 and 4.39 nm wavelengths after 800 °C annealing. C/B4C multilayer structure has been tested over a period of one year to investigate its temporal stability. - Highlights: ► We reported the experimental results on thermal stability of C/B4C combination. ► Multilayer structure is stable even after 700 °C annealing. ► C/B4C can be used as a stable multilayer mirror both in soft and hard X-ray regions. ► C/B4C multilayer structure has shown good temporal stability

  16. Characteristics of electrodeposited RE-Ni-W-B-B4C-MoS2 composite coating

    马克毅; 郭忠诚; 朱晓云; 徐瑞东

    2003-01-01

    The high temperature oxidation resistance of RE-Ni-W-B-B4C-MoS2 composite coating, the effects of electrodeposition conditions on the morphologies of the coating and the effect of heat treatment temperature on its hardness, abrasion resistance and phase structure were investigated by using scanning electron microscope(SEM), X-ray diffractometer, microhardness tester and abrasion machine. The results show that the oxidation degree of RE-Ni-W-B-B4C-MoS2 composite coating is small when the temperature is lower than 700 ℃, but it increases sharply when the temperature is higher than 700 ℃. The hardness of RE-Ni-W-B-B4C-MoS2 composite coating increases with increasing heat treatment temperature, it comes up to the maximum value at 400 ℃,but it decreases gradually if the temperature rises continuously. The most favourable abrasion resistance was attained after RE-Ni-W-B-B4C-MoS2 composite coating being heat treated at 400 ℃. Without heat treating, it is mainly amorphous and partially crystallized, but wholly crystallized after being heat treated at 500 ℃. RE in the composite coating is in the form of CeO2 and additions of CeO2 and B4C can enhance the thermostability of RE-Ni-W-B-B4C-MoS2 composite coating.

  17. Sintering of B4C powder obtained by a modified carbo-thermal reaction

    Boron carbide is one of the hardest materials and a highly refractory material that is of great interest for structural, electronic and nuclear applications. B4C is commercially manufactured by the carbo-thermal reduction of a mixture of boron oxide (B2O3) in an batch electric arc furnace process. However the carbo-thermal reaction on the stoichiometric starting composition results an excess carbon residue because of the boron loss in the form of B2O2. Thus, a modified carbo-thermal reaction is applied with an excess B2O3 to compensate the loss and to obtain stoichiometric powders. The aim of this work is to study the sinterability of this powder with the lower carbon residue acting as sintering additive. Pressureless sintering in the temperatures of 1900 deg. C/30 min and 2100 deg. C/30 min in argon atmosphere were applied. The synthesized powders were analysed by XRD and SEM. Density of 94% of theoretical density was achieved for sample prepared with the powder obtained with 50% B2O3 excess synthesized at 1700 deg. C/15 min. (authors)

  18. Eu2O3 and B4C worth calculations in fast reactor spectra

    Work is now in progress to design and fabricate europia (Eu2O3) control rods for irradiation testing in one of the early operating cycles of the Fast Test Reactor (FTR). These tests will provide data for evaluating europia as a possible control rod absorber material in fast reactors. Prediction of the reactivity worth of the europia rods is a necessary part of the design process. To improve the accuracy of these predictions, an experiment was performed in the FTR Engineering Mockup Critical (EMC) to determine the relative reactivity worth of Eu2O3 and boron carbide (B4C) in control rod size quantities. Upon completion of the experiment, calculations were performed to obtain reactivity worths for comparison with the measured worths. From this comparison, calculation-vs.-experiment (C/E) bias factors were obtained for use in correcting the computed reactivity worth of europia in the FTR. A brief description of the experiment is presented together with the experimental results, a description of the analytical methods, the calculated results, and a comparison of the calculated and experimental results. Also included are discussions of the effects of resonance self-shielding and mesh spacing on computed absorber rod worths

  19. REVERSIBLE HYDROGEN STORAGE IN A LiBH{sub 4}-C{sub 60} NANOCOMPOSITE

    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.

  20. The peculiar radio galaxy 4C 35.06: a case for recurrent AGN activity?

    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 ...

  1. The Extended Emission-Line Region of 4C 37.43

    Stockton, A; Hu, E M; Kim, T S; Stockton, Alan; Kenty, John W. Mac; Hu, Esther M.; Kim, Tae-Sun

    2002-01-01

    We have explored the nature of the extended emission-line region around the z=0.37 quasar 4C 37.43, using extensive ground-based and HST imaging and spectroscopy. The velocity field of the ionized gas shows gradual gradients within components but large jumps between components, with no obvious global organization. The HST [O III] image shows radial linear features on the east side of the QSO that appear to mark the edges of an ionization cone. Concentrating on the bright emission peaks ~4\\arcsec$ east of the quasar, we find through modeling that we require at least two density regimes contributing significantly to the observed emission-line spectrum: one with a density of ~2 cm^-3, having essentially unity filling factor, and one with a density of ~500 cm^-3, having a very small (~10^-5) filling factor. Because the temperatures of these two components are similar, they cannot be in pressure equilibrium, and there is no obvious source of confinement for the dense regions. We estimate that the dense regions wil...

  2. The structural and electronic evolution of Li4C60 through the polymer-monomer transformation

    In this paper, we combine synchrotron powder x-ray diffraction, 7Li nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR) experiments to study the structural evolution of Li4C60 and how its electronic ground state depends on the crystal symmetry. The compound in the two-dimensional polymer phase with mixed interfullerene bonding motifs is a band gap insulator. EPR, however, reveals the presence of intrinsic centers originating from broken C60-C60 bonds and local Li off-stoichiometry that create states in the band gap and account for the complex temperature dependence of the spin susceptibility as well as the residual temperature dependence of the 7Li NMR shift. At low temperatures, the Li+ ions are statically disordered on the 7Li NMR timescale. The observed 7Li NMR line narrowing at T>200 K is ascribed to the Li+ diffusion dynamics and above room temperature the polymer phase is already a good ionic conductor. Heating the sample to temperatures above ∼470 K results in gradual depolymerization to the metallic monomer fcc high temperature structure. The transformation is first order and polymer as well as monomer phases coexist over a broad temperature interval (130 K)

  3. The warm absorber in the radio-loud quasar 4C +74.26

    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...

  4. Performance of the MTR core with MOX fuel using the MCNP4C2 code.

    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. PMID:27213809

  5. 25 Orionis: A Kinematically Distinct 10 Myr Old Group in Orion OB1a

    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...

  6. Clustering of OB-fold domains of the partner protease complexed with trimeric stomatin from Thermococcales.

    Yokoyama, Hideshi; Matsui, Eriko; Hiramoto, Kana; Forterre, Patrick; Matsui, Ikuo

    2013-07-01

    The C-terminal soluble domain of stomatin operon partner protein (STOPP) of the hyperthermophilic archaeon Pyrococcus horikoshii has an oligonucleotide binding-fold (OB-fold). STOPP lacks the conserved surface residues necessary for binding to DNA/RNA. A tryptophan (W) residue is conserved instead at the molecular surface. Solvent-accessible W residues are often found at interfaces of protein-protein complexes, which suggested the possibility of self-assembling of STOPP. Protein-protein interactions among the C-terminal soluble domains of STOPP PH1510 (1510-C) were then analyzed by chemical linking and blue native polyacrylamide gel electrophoresis (BN-PAGE) methods. These results suggest that the soluble domains of STOPP could assemble into homo-oligomers. Since hexameric subcomplex I from archaeal proteasome consists of coiled-coil segments and OB-fold domains, molecular modeling of 1510-C was performed using hexameric subcomplex I as a template. Although 1510-C is a comparatively small polypeptide consisting of approximately 60 residues, numerous salt bridges and hydrophobic interactions were observed in the predicted hexamer of 1510-C, suggesting the stability of the homo-oligomeric structure. This oligomeric property of STOPP may be favorable for triplicate proteolysis of the trimer of prokaryotic stomatin. PMID:23587725

  7. Občianstvo po narodení a nie po smrti!

    Kissová Lenka

    2014-01-01

    Taliansko je jednou z európskych krajín, ktorá má bohatú emigračnú ako aj imigračnú minulosť. Zároveň je jednou zo vstupných brán do Európy pre ľudí utekajúcich primárne z krajín Afriky. Ročne prichádzajú na jeho brehy tisíce utečencov, zároveň ale nachádzajú pri jeho brehoch smrť mnohí z nich. Príspevok má za cieľ priblížiť imigračnú politiku tejto krajiny a podmienky pre nadobudnutia talianskeho občianstva. Záverom príspevku je krátka reflexia udelenia talianskeho občianstva ex post obetiam...

  8. Accretion and outflow in the proplyd-like objects near Cygnus OB2

    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.

  9. Magnetic field measurements and wind-line variability of OB-type stars

    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...

  10. On the importance of the wind emission to the optical continuum of OB supergiants

    Kraus, Michaela; Krticka, Jiri

    2008-01-01

    Thermal wind emission in the form of free-free and free-bound emission is known to show up in the infrared and radio continuum of hot and massive stars. For OB supergiants with moderate mass loss rates and a wind velocity distribution with \\beta = 0.8...1.0, no influence of the wind to the optical continuum, i.e. for \\lambda 1. For the case of a spherically symmetric, isothermal wind in local thermodynamical equilibrium (LTE) we calculate the free-free and free-bound processes and the emerging wind and total continuum spectra. We localize the generation region of the optical wind continuum and especially focus on the influence of a \\beta-type wind velocity distribution with \\beta > 1 on the formation of the wind continuum at optical wavelengths. The optical wind continuum is found to be generated within about 2 R_* which is exactly the wind region where \\beta strongly influences the density distribution. We find that for \\beta > 1, the continuum of a typical OB supergiant can indeed be contaminated with ther...

  11. A Candidate for the Most Luminous OB Association in the Galaxy

    Rahman, Mubdi; Matzner, Christopher; Moon, Dae-Sik

    2011-02-01

    The Milky Way harbors giant H II regions, which may be powered by star complexes more luminous than any known Galactic OB association. Being across the disk of the Galaxy, however, these brightest associations are severely extinguished and confused. We present a search for one such association toward the most luminous H II region in the recent catalog by Murray & Rahman, which, at ~9.7 kpc, has a recombination rate of ~7 × 1051 s-1. Prior searches have identified only small-scale clustering around the rim of this shell-like region, but the primary association has not previously been identified. We apply a near-infrared color selection and find an overdensity of point sources toward its southern central part. The colors and magnitudes of these excess sources are consistent with O- and early B-type stars at extinctions 0.96 < AK < 1.2, and they are sufficiently numerous (406 ± 102 after subtraction of field sources) to ionize the surrounding H II region, making this a candidate for the most luminous OB association in the Galaxy. We reject an alternate theory, in which the apparent excess is caused by localized extinction, as inconsistent with source demographics.

  12. OB Associations at the Upper End of the Milky Way Luminosity Function

    Rahman, Mubdi; Moon, Dae-Sik

    2012-01-01

    The Milky Way's most luminous, young and massive (M > 10^4 Msun) star clusters and OB associations have largely evaded detection despite knowledge of their surrounding H II regions. We search for these clusters and associations within the 40 star forming complexes from Rahman & Murray in the 13 most luminous WMAP free-free emission sources of the Galaxy. Selecting for objects with the dust-reddened colors of OB stars, we identify new candidate associations using the 2MASS point source catalog. In 40 star forming complexes searched, 22 contain cluster/association candidates with sizes and masses in the range of 3' - 26' and 10^{2.3} - 10^{5} Msun. Of the 22 candidates, at least 7 have estimated masses > 10^4 Msun, doubling the number of such massive clusters known in the Galaxy. Applying our method to a statistically similar set of test locations, we estimate that 3.0 +/- 0.6 of our 22 candidate associations are unrelated to the star forming complexes. In addition, the apparent extinctions of our candidate...

  13. The Adult Ventricular-Subventricular Zone (V-SVZ) and Olfactory Bulb (OB) Neurogenesis.

    Lim, Daniel A; Alvarez-Buylla, Arturo

    2016-01-01

    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. PMID:27048191

  14. Investigation of CygOB2 #11 (O5 Ifc) by modeling its atmosphere

    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...

  15. An Adaptive Loss-Aware Flow Control Scheme for Delay-Sensitive Applications in OBS Networks

    Jeong, Hongkyu; Choi, Jungyul; Mo, Jeonghoon; Kang, Minho

    Optical Burst Switching (OBS) is one of the most promising switching technologies for next generation optical networks. As delay-sensitive applications such as Voice-over-IP (VoIP) have recently become popular, OBS networks should guarantee stringent Quality of Service (QoS) requirements for such applications. Thus, this paper proposes an Adaptive Loss-aware Flow Control (ALFC) scheme, which adaptively decides on the burst offset time based on loss-rate information delivered from core nodes for assigning a high priority to delay-sensitive application traffic. The proposed ALFC scheme also controls the upper-bounds of the factors inducing delay and jitter for guaranteeing the delay and jitter requirements of delay-sensitive application traffic. Moreover, a piggybacking method used in the proposed scheme accelerates the guarantee of the loss, delay, and jitter requirements because the response time for flow control can be extremely reduced up to a quarter of the Round Trip Time (RTT) on average while minimizing the signaling overhead. Simulation results show that our mechanism can guarantee a 10-3 loss-rate under any traffic load while offering satisfactory levels of delay and jitter for delay-sensitive applications.

  16. Accretion and outflow in the proplyd-like objects near Cygnus OB2

    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.

  17. Občanská věda v ornitologii

    Voříšek, Petr; Vermouzek, Zdeněk

    2013-01-01

    Občanská věda je relativně nový termín pro taková vědecká bádání, na nichž se kromě profesionálních vědců významnou nebo rozhodující měrou podílejí i amatéři zabývající se danou problematikou ve svém volném čase. Přestože termín je nový, výzkumy podobného charakteru se prováděly a provádějí již dlouho. Právě ornitologie je jedním z oborů, kde má občanská věda dlouhou tradici a můžeme tak na řadě příkladů demonstrovat přínosy, úskalí i hlavní specifika tohoto způsobu vědeckého poznávání světa....

  18. Leptin and the obesity receptor (OB-R) in the small intestine and colon: a colocalization study

    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...

  19. Model prehoda v trajnostno krožno ekonomijo v občini Kočevje

    Pisk, Valter

    2016-01-01

    V magistrskem delu je predstavljen model prehoda v trajnostno krožno ekonomijo v občini Kočevje kot podlaga za izboljšanje gospodarskih in socialnih razmer v občini. Koncept krožnega gospodarstva temelji na načelu identifikacije in čim večjega izkoriščanja lokalnih potencialov ter dviga dodane vrednosti v lokalnem okolju z vsemi multiplikativnimi učinki, ki pri tem nastanejo. Največji razvojni potencial občine Kočevje predstavlja gozd, ki še ni izkoriščen v zadostni meri. Koncept temelji na i...

  20. Ocena jakości obsługi klienta w procesie kształtowania jego satysfakcji

    Kurnyta, Maciej

    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...

  1. The structure of KPN03535 (gi|152972051), a novel putative lipoprotein from Klebsiella pneumoniae, reveals an OB-fold

    KPN03535 is a protein unique to K. pneumoniae. The crystal structure reveals that KPN03535 represents a novel variant of the OB-fold and is likely to be a DNA-binding lipoprotein. KPN03535 (gi|152972051) is a putative lipoprotein of unknown function that is secreted by Klebsiella pneumoniae MGH 78578. The crystal structure reveals that despite a lack of any detectable sequence similarity to known structures, it is a novel variant of the OB-fold and structurally similar to the bacterial Cpx-pathway protein NlpE, single-stranded DNA-binding (SSB) proteins and toxins. K. pneumoniae MGH 78578 forms part of the normal human skin, mouth and gut flora and is an opportunistic pathogen that is linked to about 8% of all hospital-acquired infections in the USA. This structure provides the foundation for further investigations into this divergent member of the OB-fold family

  2. Effect of microstructure on low temperature electrochemical properties of LiFePO4/C cathode material

    Graphical abstract: The low temperature performance of Li-ion batteries and LiFePO4/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 LiMn2O4, LiNi1/3Co1/3Mn1/3O2 and LiFePO4/C as cathode materials. The low temperature performance results indicate the LiFePO4/C microstructure is the main factor influencing the low temperature performance of LiFePO4. A new LiFePO4/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 LiFePO4/C composite was discussed. • Cathode material mainly decided the low temperature performance of Li-ion battery. • LiFePO4/C microstructure mainly affects its low temperature performance. • Pomegranate-like spherical structure LiFePO4/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 LiMn2O4, LiNi1/3Co1/3Mn1/3O2, and LiFePO4/C as the cathode, respectively, at −20 °C. LiFePO4/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 indicate that the microstructure of LiFePO4/C is a key factor determining the low-temperature performance of LiFePO4/C. A new type of

  3. FERMI LARGE AREA TELESCOPE DETECTION OF BRIGHT γ-RAY OUTBURSTS FROM THE PECULIAR QUASAR 4C +21.35

    In this paper, we report on the two-year-long Fermi-Large Area Telescope observation of the peculiar blazar 4C +21.35 (PKS 1222+216). This source was in a quiescent state from the start of the science operations of the Fermi Gamma-ray Space Telescope in 2008 August until 2009 September, and then became more active, with gradually increasing flux and some moderately bright flares. In 2010 April and June, 4C +21.35 underwent a very strong GeV outburst composed of several major flares characterized by rise and decay timescales of the order of a day. During the outburst, the GeV spectra of 4C +21.35 displayed a broken power-law form with spectral breaks observed near 1-3 GeV photon energies. We demonstrate that, at least during the major flares, the jet in 4C +21.35 carried a total kinetic luminosity comparable to the total accretion power available to feed the outflow. We also discuss the origin of the break observed in the flaring spectra of 4C +21.35. We show that, in principle, a model involving annihilation of the GeV photons on the He II Lyman recombination continuum and line emission of 'broad-line region' clouds may account for such. However, we also discuss the additional constraint provided by the detection of 4C +21.35 at 0.07-0.4 TeV energies by the MAGIC telescope, which coincided with one of the GeV flares of the source. We argue that there are reasons to believe that the ∼17 cm from the nucleus), but instead originates further away from the active center, namely, around the characteristic scale of the hot dusty torus surrounding the 4C +21.35 nucleus (∼1019 cm).

  4. Microstructure and mechanical properties of pulsed electric current sintered B4C-TiB2 composites

    Research highlights: → Fast densification of B4C-TiB2 particulate composites. → Oxide impurity removal by evaporation. → Judiciously controlled loading cycle during pulsed electric current sintering. → High strength micrometer sized B4C-TiB2 composites. - Abstract: Monolithic B4C, TiB2 and B4C-TiB2 particulate composites were consolidated without sintering additives by means of pulsed electric current sintering in vacuum. Sintering studies on B4C-TiB2 composites were carried out to reveal the influence of the pressure loading cycle during pulsed electrical current sintering (PECS) on the removal of oxide impurities, i.e. boron oxide and titanium oxide, hereby influencing the densification behavior as well as microstructure evolvement. The critical temperature to evaporate the boron oxide impurities was determined to be 2000 deg. C. Fully dense B4C-TiB2 composites were achieved by PECS for 4 min at 2000 deg. C when applying the maximum external pressure of 60 MPa after volatilization of the oxide impurities, whereas a relative density of 95-97% was obtained when applying the external pressure below 2000 deg. C. Microstructural analysis showed that B4C and TiB2 grain growth was substantially suppressed due to the pinning effect of the secondary phase and the rapid sintering cycle, resulting in micrometer sized and homogeneous microstructures. Excellent properties were obtained for the 60 vol% TiB2 composite, combining a Vickers hardness of 29 GPa, a fracture toughness of 4.5 MPa m1/2 and a flexural strength of 867 MPa, as well as electrical conductivity of 3.39E+6 S/m.

  5. Ocean Basalt Simulator version 1 (OBS1): Trace element mass balance in adiabatic melting of a pyroxenite-bearing peridotite

    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.

  6. The oligonucleotide binding (OB-fold domain of KREPA4 is essential for stable incorporation into editosomes.

    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.

  7. The peculiar radio galaxy 4C 35.06: a case for recurrent AGN activity?

    Shulevski, A.; Morganti, R.; 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.

    2015-07-01

    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 outermost regions of radio emission have a steep spectral index (α< - 1), indicative of old plasma. We connect the spectral index properties of the resolved source structure with the integrated fluxdensity spectral index of 4C 35.06 and suggest an explanation for its unusual integrated flux density spectral shape (a moderately steep power law with no discernible spectral break), possibly providing a proxy for future studies of more distant radio sources through inferring their detailed spectral index properties and activity history from their integrated spectral indices. The AGN is hosted by one of the galaxies located in the cluster core of Abell 407. We propose that it is intermittently active as it moves in the dense environment in the cluster core. In this scenario, the AGN turned on sometime in the past, and has produced the helical pattern of emission, possibly a sign of jet precession/merger during that episode of activity. Using LOFAR, we can trace the relic plasma from that episode of activity out to greater distances from the core than ever

  8. Mechanism for amorphization of boron carbide B4C under uniaxial compression

    Aryal, Sitaram; Rulis, Paul; Ching, W. Y.

    2011-11-01

    Boron carbide undergoes an amorphization transition under high-velocity impacts, causing it to suffer a catastrophic loss in strength. The failure mechanism is not clear and this limits the ways to improve its resistance to impact. To help uncover the failure mechanism, we used ab initio methods to carry out large-scale uniaxial compression simulations on two polytypes of stoichiometric boron carbide (B4C), B11C-CBC, and B12-CCC, where B11C or B12 is the 12-atom icosahedron and CBC or CCC is the three-atom chain. The simulations were performed on large supercells of 180 atoms. Our results indicate that the B11C-CBC (B12-CCC) polytype becomes amorphous at a uniaxial strain s = 0.23 (0.22) and with a maximum stress of 168 (151) GPa. In both cases, the amorphous state is the consequence of structural collapse associated with the bending of the three-atom chain. Careful analysis of the structures after amorphization shows that the B11C and B12 icosahedra are highly distorted but still identifiable. Calculations of the elastic coefficients (Cij) at different uniaxial strains indicate that both polytypes may collapse under a much smaller shear strain (stress) than the uniaxial strain (stress). On the other hand, separate simulations of both models under hydrostatic compression up to a pressure of 180 GPa show no signs of amorphization, in agreement with experimental observation. The amorphized nature of both models is confirmed by detailed analysis of the evolution of the radial pair distribution function, total density of states, and distribution of effective charges on atoms. The electronic structure and bonding of the boron carbide structures before and after amorphization are calculated to further elucidate the mechanism of amorphization and to help form the proper rationalization of experimental observations.

  9. Posodobitev logistične infrastrukture v občini Radenci : diplomsko delo univerzitetnega študija

    Kranjc, Alen

    2011-01-01

    Diplomsko delo predstavlja raziskovalno delo na področju logistične infrastrukture v Občini Radenci, ki ima velik potencial v razvoju gospodarstva in turizma. S teoretičnim delom in raziskavo smo izpolnili cilje, ki smo si jih zastavili v uvodnem delu diplomske naloge ter predstavili kako bi z optimalnimi rešitvami na področju logistične infrastrukture v občini lahko posodobili in nudili oporo gospodarstvu in turizmu. Raziskava kaže, da vlada nezadovoljstvo z obstoječo logistič...

  10. The MiMeS Survey of Magnetism in Massive Stars

    Wade, G. A.; Grunhut, J. H.; collaboration, the MiMeS

    2012-01-01

    The Magnetism in Massive Stars (MiMeS) survey represents a high precision systematic search for magnetic fields in hot, massive OB stars. To date, MiMeS Large Programs (ESPaDOnS@CFHT, Narval@TBL, HARPSpol@ESO3.6) and associated PI programs (FORS@VLT) have yielded nearly 1200 circular spectropolarimetric observations of over 350 OB stars. Within this sample, 20 stars are detected as magnetic. Follow-up observations of new detections reveals (i) a large diversity of magnetic properties, (ii) ev...

  11. Facile Hydrothermal Synthesis of Fe3O4/C Core-Shell Nanorings for Efficient Low-Frequency Microwave Absorption.

    Wu, Tong; Liu, Yun; Zeng, Xiang; Cui, Tingting; Zhao, Yanting; Li, Yana; Tong, Guoxiu

    2016-03-23

    Using elliptical iron glycolate nanosheets as precursors, elliptical Fe3O4/C core-shell nanorings (NRs) [25 ± 10 nm in wall thickness, 150 ± 40 nm in length, and 1.6 ± 0.3 in long/short axis ratio] are synthesized via a one-pot hydrothermal route. The surface-poly(vinylpyrrolidone) (PVP)-protected-glucose reduction/carbonization/Ostwald ripening mechanism is responsible for Fe3O4/C NR formation. Increasing the glucose/precursor molar ratio can enhance carbon contents, causing a linear decrease in saturation magnetization (Ms) and coercivity (Hc). The Fe3O4/C NRs reveal enhanced low-frequency microwave absorption because of improvements to their permittivity and impedance matching. A maximum RL value of -55.68 dB at 3.44 GHz is achieved by Fe3O4/C NRs with 11.95 wt % C content at a volume fraction of 17 vol %. Reflection loss (RL) values (≤-20 dB) are observed at 2.11-10.99 and 16.5-17.26 GHz. Our research provides insights into the microwave absorption mechanism of elliptical Fe3O4/C core-shell NRs. Findings indicate that ring-like and core-shell nanostructures are promising structures for devising new and effective microwave absorbers. PMID:26915716

  12. Cupric ion substituted LiFePO4/C composites with enhanced electrochemical performance for Li-ion batteries

    Cupric ion substituted LiFePO4/C composites were successfully synthesized via a two-step solid state reaction method. The SEM mapping demonstrates that cupric is well substituted in LiFePO4. Interestingly, the XRD spectra indicate that the substituted cupric could enlarge the interplanar distance of planes that parallelled to [010] direction of LiFePO4 crystallines, which could widens the diffusion channels of Li+ along [010] direction. For further research, Lithium ion storage behavior of as-synthesized cupric ion substituted LiFePO4/C products were investigated via various electrochemical strategies, and the highest capacity of 152.4, 144.4, 126.7 and 110.5 mAh g−1 was achieved by LiFe0.985Cu0.015PO4/C at discharge rate of 1, 2, 5, and 10 C, respectively. Compared the result with that of LiFePO4/C, we can see that cupric ion substituted LiFePO4/C composites show enhanced electrochemical activity for Li+ storage with decreased overpotential and increased high rate capability for electrochemical reaction

  13. Preparation and performance of Nano-LiFePO4/C cathode material for lithium-ion battery

    Qin, Xianzhong; Yang, Gai; Ma, Feng; Cai, Feipeng

    2016-01-01

    A high energy density LiFePO4/C material for lithium batteries was synthesized by controlled crystallization-carbothermal reaction, which has been experienced as an effective process for mass production of electrode materials. The structure and morphology of the LiFePO4/C material were characterized by X-ray diffraction and Scanning Electron Microscope (SEM). The electrochemical properties of the synthesized nano-LiFePO4/C were investigated by charge-discharge processing and cyclic voltammetry (CV). The initial discharge capacities of the LiFePO4/C battery were 163.9, 158.4, 154.5, 151.4, and 142 mA h g-1 at 0.1C, 1C, 2C, 5C, and 10C, respectively. The capacity of LiFePO4/C material maintained 98.5% at the rate of 1C after 100 cycles, demonstrating excellent rate capability and cycling performance.

  14. Effect of gelatin concentration on the synthetize of the LiFePO4/C composite for lithium ion batteries

    Highlights: • Gelatin has been used to regulate and control the synthesis of LiFePO4/C composite. • Influence of gelatin concentration on crystal structure of LiFePO4 has been observed. • The shape transformation from sphere-like to rod-like structure of LiFePO4/C has been revealed. - Abstract: Gelatin is an effective additive of the cathode, which would regulate and control the crystal and morphology of LiFePO4/C composite for enhancing electrochemical performance of the lithium ion battery. The influence of gelatin concentration on the preparation of LiFePO4/C composite has been investigated. It is observed by SEM that the shape transformed from sphere-like to rod-like structure with the gelatin concentration increased from 1 wt.% to 5 wt.%; meanwhile, the lattice parameters first showed increase trend and then decrease. The LiFePO4/C composite obtained with the 2 wt.% gelatin solution shows the lowest polarization and excellent rate performance

  15. Histone Demethylases KDM4A and KDM4C Regulate Differentiation of Embryonic Stem Cells to Endothelial Cells

    Liangtang Wu

    2015-07-01

    Full Text Available Understanding epigenetic mechanisms regulating embryonic stem cell (ESC differentiation to endothelial cells may lead to increased efficiency of generation of vessel wall endothelial cells needed for vascular engineering. Here we demonstrated that the histone demethylases KDM4A and KDM4C played an indispensable but independent role in mediating the expression of fetal liver kinase (Flk1 and VE-cadherin, respectively, and thereby the transition of mouse ESCs (mESCs to endothelial cells. KDM4A was shown to bind to histones associated with the Flk1 promoter and KDM4C to bind to histones associated with the VE-cadherin promoter. KDM4A and KDM4C were also both required for capillary tube formation and vasculogenesis in mice. We observed in zebrafish that KDM4A depletion induced more severe vasculogenesis defects than KDM4C depletion, reflecting the early involvement of KDM4A in specifying endothelial cell fate. These findings together demonstrate the essential role of KDM4A and KDM4C in orchestrating mESC differentiation to endothelial cells through the activation of Flk1 and VE-cadherin promoters, respectively.

  16. Fission products measured from highly-enriched uranium irradiated under 10B4C in a research reactor

    Prior work has demonstrated the use of a natural B4C capsule for spectral-tailoring in a mixed spectrum reactor as an alternate and complementary method to critical assemblies for performing nuclear data measurements at near 235U fission-energy neutron spectrum. Previous fission product measurements showed that the neutron spectrum achievable with natural B4C was not as hard as what can be achieved with critical assemblies. New measurements performed with the Washington State University TRIGA reactor using a B4C capsule 96 % enriched in 10B resulted in a neutron spectrum very similar to a critical assembly and a pure 235U fission spectrum. Fission product yields measured following an irradiation of a sample with this new method and subsequent radiochemical separations are presented here. (author)

  17. Structure and characteristics of electrodeposited RE-Ni-W-P-B4C-PTFE composite coatings

    陈凌; 郭忠诚; 杨显万

    2001-01-01

    Hardness, friction and wear characteristics of electrodeposited RE-Ni-W-P-B4C-PTFE composite coatings were studied, and the reason for these fine characteristics was explained in respect of structure. The results show that 1)the structure of RE-Ni-W-P-B4C-PTFE composite coatings experiences a transformation process from amorphous to mixture then to crystal as the heat-treatment temperature rises; 2) incorporating of B4C greatly increases the hardness of the coating; 3) the wear resistance of the coating is best with heat-treatment for 1 h at 300 ℃, which is greatly superior to that of the other traditional coatings.

  18. Characterization of Co-60 sources to the treatment of the ophthalmic tumors using the MCNP-4C code

    Ophthalmic sources used in the treatment of ophthalmic tumors needed to be periodically controlled in order to have assurance of the administrated dose in the treatment. For this purpose, an human eye was simulated with all structures and composition was simulated by MCNP-4C with an ophthalmic source of Co-60 (model CKA-4 of Amersham). With this simulator, it was possible to determine the dose in the center-eye dephness and also the doses in the structures as retina, coroide, lenses, etc. To check the doses from MCNP-4C, it was realized measurements with radiological films type X-OMAT V of Kodak, with a Co-60 CKA-4 source and an acrylic simulator. The measurement allow the construction of the optical density versus the source distance. This curve will serve as a test data for the calculated dose values of MCNP-4C. (author)

  19. g4c2c: A Model for Citizen Engagement at Arms’ Length from Government

    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.

  20. Calibration of a foot borne spectrometry system using the MCNP 4C code

    The increased interest for the cycling of radioactive Caesium in natural ecosystems has gained need for rapid and reliable methods to investigate the deposition density in natural soils. One commonly used method, soil sampling, is a good method that correctly used gives information of both the horizontal and vertical distribution of the desired nuclide. The main disadvantage is that the method is time consuming regarding sampling, preparation and measurements. An alternative method is the use of semiconductors or scintillation detectors in the field i.e. in cars, airplanes, or helicopters. Theses methods are rapid and integrate over large areas which gives a more reliable mean value provided that the operator has some basic knowledge about the depth distribution of the radio nuclides and bulk density in the soil. To be effective the systems are often connected to a GPS to give the exact coordinate for each measurement. In a situation where the area of interest is too large to cover by soil samples and measurements by airplane not will give a spatial resolution good enough, one feasible method is to use a foot borne gamma spectrometry system. The advantage of a foot borne system is that the operator can cover a quite large area within a few hours and that the method can detect small anomalies in the deposition field which may be difficult to discover with soil samples. This abstract describes the calibration of a foot borne gamma-spectrometry system carried in a back-pack and consisting of a NaI-detector, a GPS and a system for logging activity and position. The detector system and surroundings has been modeled in the Monte Carlo code MCNP 4C (Figure 1). The Monte Carlo method gives the possibility to study the influence of complex geometries that are difficult to create for a practical calibration using real activity. The results of the MCNP calibration model, has been compared to foot borne gamma-spectrometry field measurements in a Cs-137 deposition area. A

  1. Actions of a proline analogue, L-thiazolidine-4-carboxylic acid (T4C, on Trypanosoma cruzi.

    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.

  2. Synthesis of Nano FePO4 and Electrochemical Characterization of Composite Cathode Material LiFePO4/C

    WU Yu-Ling, PU Wei-Hua, REN Jian-Guo, JIANG Chang-Yin, WAN Chun-Rong

    2012-04-01

    Full Text Available Nano FePO4·xH2O powders were synthesized by controlled crystallization method, using Fe(3) compound as the iron source. The nano FePO4·xH2O powders were pretreated at 500¡䟦or 4 h in air to obtain nano FePO4 precursor. Then the olivine nano LiFePO4/C composites were obtained through carbonthermal reduction process at different temperatures. The structure, morphology, physicochemical properties and electrochemical properties of the nano FePO4·xH2O powder, FePO4 precursor and LiFePO4/C composites synthesized at different temperatures were characterized in detail by thermogravimetric/differential scanning calorimeter (TG/DSC), X―ray diffraction (XRD), scanning?electron?microscope (SEM), Brunauer―Emmett―Teller (BET) surface area measurement and electrochemical measurement. The results show that the nano LiFePO4/C composite calcined at 700¡䟦or 10 h has fine particle sizes of about 40―100 nm .The BET test shows that the as―prepared nano LiFePO4/C composite has great specific surface area of 79.8 m2/g. The nano LiFePO4/C composite cathode material can deliver an initial discharge capacity of 156.5, 134.9, 105.8, 90.3 and 80.9 mAh/g in the voltage range of 2.5―4.2 V, at rate of 0.1C, 1C, 5C, 10C and 15C respectively, which exhibits good rate performance. The nano LiFePO4/C composite also demonstrates excellent cyclic performance.

  3. Preparation and electrochemical performance of LiFePO4/C microspheres by a facile and novel co-precipitation

    Graphical abstract: Display Omitted -- Highlights: •LiFePO4/C microspheres are synthesized via a facile co-precipitation in an elevated temperature oil. •PVA acts as a binder in co-precipitation reaction to restrain the free split of the droplets and promote the formation of uniform spherical precursor. •LiFePO4/C microspheres are composed of nanoparticles which are coated by a thin nano-carbon layer and imbedded into three-dimensional nano-carbon networks. •LiFePO4/C microspheres exhibit an high tap density (1.82 g cm−3), deliver large reversible discharge capacity of 106 mA h g−1 at 50C rate, and capacity retention rate over 98% after 20 cycles at various current densities. -- Abstract: LiFePO4 and LiFePO4/C microspheres are successfully synthesized via facile co-precipitation in an elevated temperature oil bath. Their morphologies and structures are investigated by X-ray diffractometer, scanning electron microscope and transmission electron microscope. LiFePO4/C microspheres are uniform between 2 and 4 μm in diameter and composed of nanoparticles from 30 to 80 nm in size. Nanoparticles are coated by a thin nano-carbon layer and imbedded into three-dimensional nano-carbon networks. LiFePO4/C microspheres exhibit a high tap density (1.82 g cm−3), deliver large reversible discharge capacity of 165 mA h g−1 at 0.1C rate, excellent rate capability of 106 mA h g−1 at 50C rate, and capacity retention over 98% after 20 cycles even applied 50C rate. Therefore, the material is a potential candidate for high-power lithium ion batteries

  4. Radioactive pollution of the Ob river system from Urals nuclear enterprise 'MAJAK'

    The Techa river belongs to the Iset-Tobol-Irtysh-Ob river system. Around 1950 the Techa was contaminated with medium and high level radioactive waste from the MAJAK nuclear installation. The total discharge amounted to 100 PBq; 90Sr and 137Cs contributed 11.6% and 12.2% respectively. Presently the Techa contains about 0.3 TBq 90Sr, more than 6 TBq 137Cs and about 8 GBq 239,240Pu. The levels of the radionuclides upstream are several orders of magnitude higher than those expected from global fallout. The activity concentrations decrease exponentially or by power functions with distance. The study has shown that the contamination of the soil of the Techa flood plain is 15-85 times higher than global fallout levels. There is an unexplained radioactive contamination in the Iset river after confluence with the Techa. (author)

  5. MODELING THE RADIO EMISSION FROM Cyg OB2 NO. 5: A QUADRUPLE SYSTEM?

    Fifty observations at frequencies between 1.4 GHz and 43 GHz of the 6.6 day O6.5-7+O5.5-6 binary Cyg OB2 No. 5 using the Very Large Array over 20 years are re-examined. The aim is to determine the location and character of the previously detected variable radio emission. The radio emission from the system consists of a primary component that is associated with the binary, and a non-thermal source (NE), 0.''8 to the NE of the binary that has been ascribed to a wind-collision region (WCR) between the stellar winds of the binary and that of a B-type star (Star D) to the NE. Previous studies have not accounted for the potential contribution of NE to the total radio emission, most especially in observations where the primary and NE sources are not resolved as separate sources. NE shows no evidence of variation in 23 epochs where it is resolved separately from the primary radio component, demonstrating that the variable emission arises in the primary component. Since NE is non-variable, the radio flux from the primary can now be well determined for the first time, most especially in observations that do not resolve both the primary and NE components. The variable radio emission from the primary component has a period of 6.7 ± 0.3 years which is described by a simple model of a non-thermal source orbiting within the stellar wind envelope of the binary. Such a model implies the presence of a third, unresolved stellar companion (Star C) orbiting the 6.6 day binary with a period of 6.7 years and independent of Star D to the NE. The variable non-thermal emission arises from either a WCR between Star C and the binary system, or possibly from Star C directly. The model gives a mass-loss rate of 3.4 x 10-5 Msun yr-1 for Cyg OB2 No. 5, unusually high for an Of supergiant and comparable to that of WR stars, and consistent with an unusually strong He I 1.083 μm emission line, also redolent of WR stars. An examination of radial velocity observations available from the literature

  6. Period change of massive binaries from combined photometric and spectroscopic data in Cygnus OB2

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

    2015-01-01

    Context. Mass loss is an important property in evolution models of massive stars. As up to 90% of the massive stars have a visual or spectroscopic companion and many of them exhibit mass exchange, mass-loss rates can be acquired through the period study of massive binaries. Aims. Using our own photometric observations as well as archival data, we look for variations in orbital periods of seven massive eclipsing binary systems in the Cygnus OB2 association and estimate their mass-loss rates and stellar parameters. Methods. We use a Bayesian parameter estimation method to simultaneously fit the period and period change to all available data and a stellar modelling tool to model the binary parameters from photometric and radial-velocity data. Results. Four out of the seven selected binaries show non-zero period change values at two-sigma confidence level. We also report for the first time the eclipsing nature of a star MT059.

  7. A formation scenario of young stellar groups in the region of the Scorpio Centaurus OB association

    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.

  8. Environmental pollutants in the Kara Sea and estuaries of Ob and Yenisey

    The Arctic has been identified as an area that is particularly vulnerable to adverse effects from environmental perturbations. Renewed attention has been focused on examining levels and assessing the effects of anthropogenic pollutants found in critical habitats within the Arctic. In 1993, the Russian-Norwegian oceanographic programme (RusNoP) launched the scientific program KAREX, an investigation in the Kara Sea and the estuaries of the Ob and Yenisey. RusNoP is a co-operation between the Arctic and Antarctic Research Institute and the Norwegian Polar Institute. The primary objective of the KAREX-94 program was to identify current levels of sediment-bound contaminants in the Kara Sea region and to elucidate possible contaminant transport routes. Pollutants measured in seabed sediment samples and an assessment of benthic macrofauna communities are presented in this paper. Pollutants examined are hydrocarbons, organics, pesticides, and heavy metals

  9. Effect of B sub(4)C addition on the sinterability of Al sub(2)O sub(3)

    In this paper, the densification of Al sub(2)O sub(3) pellets as a function of sintering temperature and B sub(4)C concentration has been studied. Additions of up to 15wt% B sub(4)C of two different granulometries have been considered. Sintering was carried out in a helium atmosphere in the temperature range 1400 to 1700 sup(o)C. Informations about the formation of aluminium carbide, resulting from the reaction of alumina with the graphite crucible have also been presented. (author)

  10. SYNTHESIS AND CHARACTERIZATION OF LiFePO4/C PREPARED VIA A SOL–GEL METHOD

    YAN LIN; HONGGE PAN; MINGXIA GAO; HE MIAO; SHOUQUAN LI; YUE WANG

    2008-01-01

    Carbon-coated lithium ion phosphate was synthesized from a gel precursor with ferric iron and a carbon source of organic chelating agent via a sol–gel method. The dependence of the microstructure and electrochemical performance of the synthesized LiFePO4/C on the pH value of the precursor solution during gel formation and the sintering time was investigated. The obtained LiFePO4/C particles were characterized by X-ray diffraction, field-emission scanning electron microscopy, and element analy...

  11. p73 G4C14 to A4T14 polymorphism is associated with colorectal cancer risk and survival

    Kyung-Eun; Lee; Young-Seoub; Hong; Byoung-Gwon; Kim; Na-Young; Kim; Kyoung-Mu; Lee; Jong-Young; Kwak; Mee-Sook; Roh

    2010-01-01

    AIM:To analyze the association between the p73 G4C14-to-A4T14 polymorphism(a.k.a.,the GC/AT variation) and colorectal cancer risk and survival in the Korean population,and to evaluate the relationships between p73 polymorphism and the p73 protein expression or clinicopathological characteristics of colorectal cancer.METHODS:Three hundred and eighty-three histologically confirmed cases and 469 healthy controls,recruited at one teaching hospital in Pusan,Korea from 2001 and 2007,were genotyped for p73 G4C14-t...

  12. Synthesis of LiFePO_4/C Composite Cathode Materials Using High Surface Area Carbon as Carbon Sources

    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...

  13. Constraints on Asian and European sources of methane from CH 4 -C 2 H 6 -CO correlations in Asian outflow

    Xiao, Yaping; Jacob, Daniel James; Wang, James; Logan, Jennifer A.; Palmer, Paul; Suntharalingam, Parvadha; Yantosca, Robert M.; Sachse, Glen; Blake, Donald; Streets, David

    2004-01-01

    Aircraft observations of Asian outflow from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the NW Pacific (March and April 2001) show large CH4 enhancements relative to background, as well as strong CH4-C2H6-CO correlations that provide signatures of regional sources. We apply a global chemical transport model simulation of the CH4-C2H6-CO system for the TRACE-P period to interpret these observations in terms of CH4 sources and to explore in particular t...

  14. SCUBA and HIRES Results for Protostellar Cores in the MON OB1 Dark Cloud

    Wolf-Chase, G.; Moriarty-Schieven, G.; Fich, M.; Barsony, M.

    1999-05-01

    We have used HIRES-processing of IRAS data and point-source modelling techniques (Hurt & Barsony 1996; O'Linger 1997; Barsony et al. 1998), together with submillimeter continuum imaging using the Submillimeter Common-User Bolometer Array (SCUBA) on the 15-meter James Clerk Maxwell Telescope (JCMT), to search CS cores in the Mon OB1 dark cloud (Wolf-Chase, Walker, & Lada 1995; Wolf-Chase & Walker 1995) for deeply embedded sources. These observations, as well as follow-up millimeter photometry at the National Radio Astronomy Observatory (NRAO) 12-meter telescope on Kitt Peak, have lead to the identification of two Class 0 protostellar candidates, which were previously unresolved from two brighter IRAS point sources (IRAS 06382+0939 & IRAS 06381+1039) in this cloud. Until now, only one Class 0 object had been confirmed in Mon OB1; the driving source of the highly-collimated outflow NGC 2264 G (Ward-Thompson, Eiroa, & Casali 1995; Margulis et al. 1990; Lada & Fich 1996), which lies well outside the extended CS cores. One of the new Class 0 candidates may be an intermediate-mass source associated with an H_2O maser, and the other object is a low-mass source which may be associated with a near-infrared jet, and possibly with a molecular outflow. We report accurate positions for the new Class 0 candidates, based on the SCUBA images, and present new SEDs for these sources, as well as for the brighter IRAS point sources. A portion of this work was performed while GWC held a President's Fellowship from the University of California. MB and GWC gratefully acknowledge financial support from MB's NSF CAREER Grant, AST97-9753229.

  15. Paris Santé Nutrition. Une approche transversale pour lutter contre le surpoids et l'obésité chez les enfants de 5 à 15 ans

    Laupeze, Alex

    2016-01-01

    Paris Santé Nutrition. Une approche transversale pour la lutte contre le surpoids et l’obésité chez les enfants de 5 à 15 ans. La question de l’obésité infantile est de plus en plus préoccupante en France. Cependant, une intervention précoce chez l’enfant en surpoids ou obèse est préconisée car elle limite l’évolution vers l’obésité à l’âge adulte. Depuis 2009, la ville de Paris, à travers le programme Paris Santé Nutrition, s’est donnée pour but de lutter contre l’obésité infantile. Elle mè...

  16. Distribution of global fallouts cesium-137 in taiga and tundra catenae at the Ob River basin

    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.

  17. Seismic location improvements from an OBS/H temporary network in Southern Tyrrhenian Sea

    G. Neri

    2006-06-01

    Full Text Available We present the first investigation performed on the seismicity of Southern Tyrrhenian Sea, off-shore Sicily with the contribution of data from broad-band ocean bottom seismometers and hydrophones (OBS/H. Offshore data were recorded during the TYrrhenian Deep sea Experiment (TYDE from December 2000 to May 2001 in the Southern Tyrrhenian Sea. Hypocenter locations of a cluster of 53 seismic events occurred in March 2001 in north-eastern Sicily were estimated by the integration of land (permanent network and offshore (temporary network data and compared with locations estimated from land data only. The scatter of the cluster was evaluated by dispersion parameters. The off-shore data significantly reduced the scatter of the swarm hypocenters also restricting the depth range of the cluster. Moreover, space trends of the event distribution originally shown by the land data were only partially confirmed by the land-sea joint data. In order to assess the efficiency in terms of hypocenter mislocations in the subject area, of a land-sea integrated network with respect to a land-based network, we performed simulations by assuming a grid distribution of earthquakes and a recent local 3D velocity model, computing synthetic arrival times of body waves to the stations of both network configurations (integrated and land-based perturbing the computed times and relocating earthquakes by inversion. The results of the synthetic tests demonstrated that the presence of sea bottom stations in the Tyrrhenian basin can reduce the mislocations of large magnitude and/or superficial earthquakes in the southernmost Calabria and Messina Strait and of low magnitude and/or deep earthquakes in north-eastern Sicily. The major accuracy of synthetic earthquake locations obtained including OBS/H data provides an additional support to the interpretation of the cluster occurred in March 2001 and to the opportunity of long-term installation of an off-shore network like TYDE in the

  18. Cerium regulates expression of alternative methanol dehydrogenases in Methylosinus trichosporium OB3b.

    Farhan Ul Haque, Muhammad; Kalidass, Bhagyalakshmi; Bandow, Nathan; Turpin, Erick A; DiSpirito, Alan A; Semrau, Jeremy D

    2015-11-01

    Methanotrophs have multiple methane monooxygenases that are well known to be regulated by copper, i.e., a "copper switch." At low copper/biomass ratios the soluble methane monooxygenase (sMMO) is expressed while expression and activity of the particulate methane monooxygenase (pMMO) increases with increasing availability of copper. In many methanotrophs there are also multiple methanol dehydrogenases (MeDHs), one based on Mxa and another based on Xox. Mxa-MeDH is known to have calcium in its active site, while Xox-MeDHs have been shown to have rare earth elements in their active site. We show here that the expression levels of Mxa-MeDH and Xox-MeDH in Methylosinus trichosporium OB3b significantly decreased and increased, respectively, when grown in the presence of cerium but the absence of copper compared to the absence of both metals. Expression of sMMO and pMMO was not affected. In the presence of copper, the effect of cerium on gene expression was less significant, i.e., expression of Mxa-MeDH in the presence of copper and cerium was slightly lower than in the presence of copper alone, but Xox-MeDH was again found to increase significantly. As expected, the addition of copper caused sMMO and pMMO expression levels to significantly decrease and increase, respectively, but the simultaneous addition of cerium had no discernible effect on MMO expression. As a result, it appears Mxa-MeDH can be uncoupled from methane oxidation by sMMO in M. trichosporium OB3b but not from pMMO. PMID:26296730

  19. 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

    Lange Consiglio, Anna; Dell'Aquila, Maria Elena; Fiandanese, Nadia; Ambruosi, Barbara; Cho, Yoon S; Bosi, Giampaolo; Arrighi, Silvana; Lacalandra, Giovanni M; Cremonesi, Fausto

    2009-01-01

    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 < 0.05) and fertilization after ICSI (56% vs 23% for 10 ng/ml leptin-treated and control groups, respectively; P < 0.05). However, the developmental rate and quality of 8-cell stage embryos derived from leptin-treated oocytes (100 ng/ml) was significantly reduced, in contrast to previous data in other species where leptin increased embryo cleavage. Ob and Ob-R proteins were detected up to the 8-cell stage with cortical and cytoplasmic granule-like distribution pattern in each blastomere. 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. PMID:19835605

  20. Rheologicai Behavior of Cationic Gemini Surfactant C18-4-C18·2Br%阳离子双子表面活性剂C18-4-C18·2Br的流变性

    陈洪; 叶仲斌; 韩利娟; 罗平亚

    2011-01-01

    The rheological behavior of cationic Gemini surfactant ( C18-4-C18'2Br) solution and the influencing factors, such as surfactant concentration, sodium salicylate concentration and temperature, on the viscosity and viscoelasticity of the solution were investigated. The viscosity of Gemini surfactant solution increases with the increase of surfactant concentration. Both the viscosity and the viscoelasticity of Gemini surfactant solution undergo a maximum with the addition of sodium salicylate. Temperature has a significant effect on the viscosity of Gemini surfactant solution. The addition of sodium salicylate can enhance the resistance performance of Gemini surfactant solution to temperature. TEM experiments show that appropriate dosage of sodium salicylate in the Gemini surfactant solution can lead to the transition of surfactant micelles from spherical micelles to wormlike micelles. However, overmuch addition of sodium salicylate will bring about the formation of vesicles in the Gemini surfactant solution.%对阳离子双子表面活性剂四亚甲基-1,2-双(十八烷基二甲基烷基溴化铵)( C18-4-C18·2Br)的流变特性进行了研究,考察了表面活性剂质量分数、水杨酸钠质量分数及温度对表面活性剂溶液黏度和黏弹性的影响.C18-4-C18·2Br溶液的黏度随着质量分数的增加而增加.随着水杨酸钠质量分数的增加,C18-4-C18·2Br溶液的黏度和黏弹性出现先增加后下降的过程.温度对C18-4-C18 ·2Br溶液的黏度有较大影响,水杨酸钠的加入可明显提高C18-4-C18·2Br溶液的抗温性.TEM结果表明,适量的水杨酸钠能够促进C18-4-C18·2Br胶束从球形向蠕虫状转变,过量的水杨酸钠又会使蠕虫状胶束向囊泡转变.

  1. Gas-and-dust complex NGC 7822 + S 171 (W1) connected with the Cep OB4 association

    The results of investigations of the gas-and-dust complex connected with the young association Cep OB4 and the cluster Be59 are presented. The monochromatic images of the bright emission nebulae S 171 (W 1) and NGC 7822 are obtained, the emission stratification typical for photoionization excitation has been revealed. The expansion velocity of faint extended shell around W1 and Cep OB4 is confirmed to be equal to 30-40 kmxs-1. The second ''inner'' shell is revealed on the basis of optical, IR and radio observations. The numerous molecular and dust clouds, emission nebulae and two faint extended shells in this region lead to a conclusion that they from the single complex associated with Cep OB4 and the young cluster Be 59. The shell-type morphology of the complex seems to be created by the stellar wind of Cep OB4 and Be 59. The expansion velocity could be explained by a supernova explosion about 3x105 years ago or by a short-lived (or invisible) source of a strong stellar wind. The expected synchrotron radioemission of this hypothetic supernova seems to be much fainter than the thermal radioemission of the ionized gas. The gas-and-dust complex mass determined from its IR emission is equal to ∼ 2x104 MSun. Mass of the gas swept out from the shell is as large as ∼ 103 MSun

  2. Vliv stočení oběžného kola na charakteristiku čerpadla

    Jelen, Richard

    2014-01-01

    Diplomová práce se zabývá změnou geometrie výstupní části oběžného kola u radiálních odstředivých čerpadel a jejímu vlivu na charakteristiku čerpadla. Při použití těchto radiálních odstředivých čerpadel v praxi je možno měnit jejich parametry na základě požadavků. Toto přizpůsobení parametrů se nazývá stočení oběžného kola. Jedná se o zmenšení průměru oběžného kola, čímž dochází ke snížení průtoku, dopravní výšky a účinnosti. Existující vztahy pro výpočet změny charakteristiky po stočení oběž...

  3. Searching for unconventional seismic signals on a subduction zone with a submerged forearc: OBS offshore the Lesser Antilles

    Bécel, Anne; Diaz, Jordi; Laigle, Mireille; Hirn, Alfred

    2013-09-01

    Detecting unconventional seismic signals related to subduction zone processes at depth in continuous ocean bottom seismometer (OBS) records requires the analysis and identification of noise due to instrumental problems, deployment sites or sea state conditions. The temporary OBS deployment at the Lesser Antilles subduction zone provides new insights into the feasibility of detecting unconventional signals such as non volcanic tremor (NVT), long-period (LP) or ultra-long period (ULP) events. Analysis of noise at an array comprising several sites and types of instruments and comparison with recordings on land shows transients in the noise. Episodes can be identified considering the diversity of sites and instrument types and comparing the seismic signals with meteorological and oceanographic data. In order to reliably detect NVT (1-10 Hz) originating from inside the solid Earth, one must first characterize noise induced by the activity of the atmosphere and hydrosphere at the sea-bottom as well as on land. The semidiurnal modulation of noise amplitude can be shown here not to be due to that of the NVT from a seismic source at depth which is related to the subduction interplate and whose activity is modulated by the tidal stresses as inferred for other megathrusts on emerged forearcs. Here, the semidiurnal modulation is rather due to the effect of the tides themselves, such as tidal currents, since they do not affect all types and all components of the unique multi-station array of OBS that could be deployed on this submerged forearc. The short period cut-off of the strong noise due to ocean surface infragravity waves increases to longer periods with OBS depth, thereby increasing the observational window with low noise to lower frequencies, and deep OBS sites may be advantageous for detecting LP events.

  4. Synthesis and electrochemical characterization of LiFePO4/C composites prepared by the microemulsion method

    Electroactive LiFePO4/C composite powders were successfully prepared by the microemulsion process under controlled conditions. A series of residual carbons on the surface of prepared LiFePO4 materials originating from the pyrolysis of various salt concentrations, Hydrophile-Lipophile-Balance (HLB) values, and structures of organic surfactants were characterized. All samples were characterized by X-ray diffraction (XRD), scanning electron microscopy (SEM), transmission electron microscopy (TEM), Raman spectral analysis, BET surface area, cyclic voltammetry (CV) and charge–discharge tests. The performance of the LiFePO4/C composite powders displayed a strong relationship between the emulsion conditions and structures of surfactants. Lower salt concentrations of the aqueous cores or a smaller HLB numbers cause the formation of small aqueous cores resulting in smaller particle sizes of LiFePO4/C composites after calcinating the cores. The molecular structures of surfactant affect the formation of micelle size and further influence the behavior of the LiFePO4/C composite. The OP-7 surfactant contains more branched structures on the lipophilic groups causing the formation of small aqueous cores and particle sizes of LiFePO4 after calcination of the cores. Small aqueous cores formed smaller particles with lower ID/IG values after pyrolysis yielding composites with higher discharge capacities.

  5. Using small punch testing method for the analysis of creep behaviour of Al-Al4C3 composites

    Besterci, M.; Dobeš, Ferdinand; Kulu, P.; Sülleiová, K.

    2010-01-01

    Roč. 16, č. 3 (2010), s. 243-254. ISSN 1736-6038 Grant ostatní: Science Grant Agency of Slovakia(SK) VEGA 2/0105/08 Institutional research plan: CEZ:AV0Z20410507 Keywords : dispersion-strengthened Al-Al4C3 composite * mechanical alloying * creep * small punch Subject RIV: JI - Composite Materials

  6. Additive synthesis with DIASS-M4C on Argonne National Laboratory`s IBM POWERparallel System (SP)

    Kaper, H.; Ralley, D.; Restrepo, J.; Tiepei, S.

    1995-12-31

    DIASS-M4C, a digital additive instrument was implemented on the Argonne National Laboratory`s IBM POWER parallel System (SP). This paper discusses the need for a massively parallel supercomputer and shows how the code was parallelized. The resulting sounds and the degree of control the user can have justify the effort and the use of such a large computer.

  7. 12 CFR 225.104 - “Services” under section 4(c)(1) of Bank Holding Company Act.

    2010-01-01

    ... company chooses to have done through another organization. Moreover, the report of the Senate Banking and... Holding Company Act. 225.104 Section 225.104 Banks and Banking FEDERAL RESERVE SYSTEM (CONTINUED) BOARD OF... Holding Company Act. (a) Section 4(c)(1) of the Bank Holding Company Act, among other things, exempts...

  8. Comparing the Electrochemical Performance of LiFePO4/C Modified by Mg Doping and MgO Coating

    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.

  9. Preparation of V-Doped LiFePO4/C as the Optimized Cathode Material for Lithium Ion Batteries.

    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. PMID:26353479

  10. Investigation on the Self-discharge of the LiFePO4/C nanophosphate battery chemistry at different conditions

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

    2014-01-01

    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. Rapid Polyol-Assisted Microwave Synthesis of Nanocrystalline LiFePO4/C Cathode for Lithium-Ion Batteries.

    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. PMID:26369219

  12. A W:B4C multilayer phase retarder for broadband polarization analysis of soft x-ray radiation

    MacDonald, Michael A.; Schaefers, Franz; Pohl, R.; Poole, Ian B.; Gaupp, Andreas; Quinn, Frances M.

    2008-01-01

    A W:B4C multilayer phase retarder has been designed and characterized which shows a nearly constant phase retardance between 640 and 850 eV photon energies when operated near the Bragg condition. This freestanding transmission multilayer was used successfully to determine, for the first time, the fu

  13. High reflectance Cr/V multilayer with B(4)C barrier layer for water window wavelength region.

    Huang, Qiushi; Fei, Jiani; Liu, Yang; Li, Pin; Wen, Mingwu; Xie, Chun; Jonnard, Philippe; Giglia, Angelo; Zhang, Zhong; Wang, Kun; Wang, Zhanshan

    2016-02-15

    To develop the high reflectance mirror for the short wavelength range of the water window region (λ=2.42-2.73  nm), Cr/V multilayers with B4C barrier layers are studied. The grazing incidence x-ray reflectometry results show that the multilayer interface widths are significantly reduced down to 0.21-0.31 nm, after the introduction of 0.1 nm B4C barrier layers at both interfaces. The [B4C/Cr/B4C/V] multilayer with a large number of bilayers of N=300 maintains the same small interface widths while the surface roughness is only 0.2 nm. According to the transmission electron microscope measurements, the layer structure improvement with barrier layers can be attributed to the suppression of the crystallization of vanadium inside the structure. Using the interface engineered multilayer, a maximum soft x-ray reflectance of 24.3% is achieved at λ=2.441  nm, under the grazing incidence of 42°. PMID:26872167

  14. Low band gap and ionic bonding with charge transfer, threshold in the polymeric lithium fulleride Li(4)C(60)

    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)

  15. Enhanced lithium storage in ZnFe2O4-C nanocomposite produced by a low-energy ball milling

    Thankachan, Rahul Mundiyaniyil; Rahman, Md Mokhlesur; Sultana, Irin; Glushenkov, Alexey M.; Thomas, Sabu; Kalarikkal, Nandakumar; Chen, Ying

    2015-05-01

    Preparation of novel nanocomposite structure of ZnFe2O4-C is achieved by combining a sol-gel and a low energy ball milling method. The crucial feature of the composite's structure is that sol-gel synthesised ZnFe2O4 nanoparticles are dispersed and attached uniformly along the chains of Super P Li™ carbon black matrix by adopting a low energy ball milling. The composite ZnFe2O4-C electrodes are capable of delivering a very stable reversible capacity of 681 mAh g-1 (96% retention of the calculated theoretical capacity of ∼710 mAh g-1) at 0.1 C after 100 cycles with a remarkable Coulombic efficiency (82%) improvement in the first cycle. The rate capability of the composite is significantly improved and obtained capacity was as high as 702 at 0.1, 648 at 0.5, 582 at 1, 547 at 2 and 469 mAh g-1 at 4 C (2.85 A g-1), respectively. When cell is returned to 0.1 C, the capacity recovery was still ∼98%. Overall, the electrochemical performance (in terms of cycling stability, high rate capability, and capacity retention) is outstanding and much better than those of the related reported works. Therefore, our smart electrode design enables ZnFe2O4-C sample to be a high quality anode material for lithium-ion batteries.

  16. Resonant soft x-ray reflectivity of Me/B(4)C multilayers near the boron K edge.

    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. PMID:20820220

  17. Synthesis and biological profiling of 6-or 7-(het)aryl-7-deazapurine 4 '-C-methylribonucleosides

    Nauš, Petr; Caletková, Olga; Perlíková, Pavla; Poštová Slavětínská, Lenka; Tloušťová, Eva; Hodek, Jan; Weber, Jan; Džubák, P.; Hajdúch, M.; Hocek, Michal

    2015-01-01

    Roč. 23, č. 23 (2015), s. 7422-7438. ISSN 0968-0896 R&D Projects: GA ČR GAP207/11/0344 Institutional support: RVO:61388963 Keywords : nucleosides * 4 '-C-methyl-ribonucleosides * branched nucleosides * nucleoside antivirals * prodrugs Subject RIV: CC - Organic Chemistry Impact factor: 2.793, year: 2014

  18. Novel magnetic Fe3O4-C nanoparticles as adsorbents for removal of organic dyes from aqueous solution

    Highlights: → In this work, novel magnetic Fe3O4-C nanoparticles have been synthesized and employed as high efficient adsorbent for removal cationic dyes from polluted water. → While up to now, little study is done on adsorption of dyes by the Fe3O4-C nanoparticles. → Hence, here we provide a simply and environment friendly method for removal of cationic dyes or other pollutants from water. - Abstract: The magnetic Fe3O4/C core-shell nanoparticles have been synthesized by a simple strategy and used as adsorbents for removal of organic dyes from aqueous solution. The resulting products are characterized by scanning electron microscope (SEM), energy dispersive X-ray spectrometry (EDX), X-ray photoelectron spectroscopy (XPS), X-ray diffraction (XRD), Raman spectra and Fourier transform infrared spectra (FTIR). Adsorption performances of the nanomaterial adsorbents are tested with removal of methylene blue (MB) and cresol red (CR) from aqueous solution. The effects of solution pH value, adsorption time and capacity of the nanocomposites have been fully investigated. The results reveal that the nanospheres can be easily manipulated by an external magnetic field with high separation efficiency. In addition, the process is clean and safe for purifying water pollution. The prepared Fe3O4/C complex nanomaterials could thus be used as promising adsorbents for the remove organic dyes, especially, cationic dye, from polluted water.

  19. Constraints on Asian and European sources of methane from CH4-C2H6-CO correlations in Asian outflow

    Xiao, Yaping; Jacob, Daniel J.; Wang, James S.; Logan, Jennifer A.; Palmer, Paul I.; Suntharalingam, Parvadha; Yantosca, Robert M.; Sachse, Glen W.; Blake, Donald R.; Streets, David G.

    2004-08-01

    Aircraft observations of Asian outflow from the Transport and Chemical Evolution Over the Pacific (TRACE-P) aircraft mission over the NW Pacific (March and April 2001) show large CH4 enhancements relative to background, as well as strong CH4-C2H6-CO correlations that provide signatures of regional sources. We apply a global chemical transport model simulation of the CH4-C2H6-CO system for the TRACE-P period to interpret these observations in terms of CH4 sources and to explore in particular the unique constraints from the CH4-C2H6-CO correlations. We use as a priori a global CH4 source inventory constrained with National Oceanic and Atmospheric Administration (NOAA) Climate Monitoring and Diagnostics Laboratory (CMDL) surface observations [Wang et al., 2004]. We find that the observed CH4 concentration enhancements and CH4-C2H6-CO correlations in Asian outflow in TRACE-P are determined mainly by anthropogenic emissions from China and Eurasia (defined here as Europe and eastern Russia), with only little contribution from tropical sources (wetlands and biomass burning). The a priori inventory overestimates the observed CH4 enhancements and shows regionally variable biases for the CH4/C2H6 slope. The CH4/CO slopes are simulated without significant bias. Matching both the observed CH4 enhancements and the CH4-C2H6-CO slopes in Asian outflow requires increasing the east Asian anthropogenic source of CH4, and decreasing the Eurasian anthropogenic source, by at least 30% for both. The need to increase the east Asian source is driven by the underestimate of the CH4/C2H6 slope in boundary layer Chinese outflow. The Streets et al. [2003] anthropogenic emission inventory for east Asia fits this constraint by increasing CH4 emissions from that region by 40% relative to the a priori, largely because of higher livestock and landfill source estimates. Eurasian sources (mostly European) then need to be reduced by 30-50% from the a priori value of 68 Tg yr-1. The decrease of

  20. NUCLEAR X-RAY PROPERTIES OF THE PECULIAR RADIO-LOUD HIDDEN AGN 4C+29.30

    We present results from a study of nuclear emission from a nearby radio galaxy, 4C+29.30, over a broad 0.5-200 keV X-ray band. This study used new XMM-Newton (∼17 ks) and Chandra (∼300 ks) data, and archival Swift/BAT data from the 58 month catalog. The hard (>2 keV) X-ray spectrum of 4C+29.30 can be decomposed into an intrinsic hard power law (Γ ∼ 1.56) modified by a cold absorber with an intrinsic column density N H,z ∼ 5 × 1023 cm–2, and its reflection (|Ω/2π| ∼ 0.3) from a neutral matter including a narrow iron Kα emission line at a rest-frame energy ∼6.4 keV. The reflected component is less absorbed than the intrinsic one with an upper limit on the absorbing column of N reflH,z 22 cm–2. The X-ray spectrum varied between the XMM-Newton and Chandra observations. We show that a scenario invoking variations of the normalization of the power law is favored over a model with variable intrinsic column density. X-rays in the 0.5-2 keV band are dominated by diffuse emission modeled with a thermal bremsstrahlung component with temperature ∼0.7 keV, and contain only a marginal contribution from the scattered power-law component. We hypothesize that 4C+29.30 belongs to a class of 'hidden' active galactic nuclei containing a geometrically thick torus. However, unlike the majority of hidden AGNs, 4C+29.30 is radio-loud. Correlations between the scattering fraction and Eddington luminosity ratio, and between black hole mass and stellar velocity dispersion, imply that 4C+29.30 hosts a black hole with ∼108 M ☉ mass.