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Sample records for bl lacertae object

  1. The Cosmological Evolution of BL Lacertae Objects

    CERN Document Server

    Giommi, P; Perri, M; Padovani, P

    2000-01-01

    We review the main results from several radio, X-ray and multi-frequency surveys on the topic of cosmological evolution of BL Lacertae objects. Updated findings on BL Lac evolution following the recent identification of many sources in the ``Sedentary Multi-Frequency survey'' are also discussed. By means of extensive Monte Carlo simulations we test some possible explanations for the peculiar cosmological evolution of BL Lacs. We find that a dependence of the relativistic Doppler factor on radio luminosity (as expected within the beaming scenario) may induce low values of V/V_max and that both edge effects at the low luminosity end of the BL Lacs radio luminosity function, and incompleteness at faint optical magnitudes may be the cause of the low V/V_max found for extreme HBL sources in X-ray selected samples.

  2. BL Lacertae Objects and the Extragalactic Gamma-Ray Background

    CERN Document Server

    Li, Fan

    2011-01-01

    A tight correlation between gamma-ray and radio emission is found for a sample of BL Lacertae (BL Lac) objects detected by Fermi Gamma-ray Space Telescope (Fermi) and the Energetic Gamma-Ray Experiment Telescope (EGRET). The gamma-ray emission of BL Lac objects exhibits strong variability, and the detection rate of gamma-ray BL Lac objects is low, which may be related to the gamma-ray duty cycle of BL Lac objects. We estimate the gamma-ray duty cycle ~ 0.11, for BL Lac objects detected by EGRET and Fermi. Using the empirical relation of gamma-ray emission with radio emission and the estimated gamma-ray duty cycle, we derive the gamma-ray luminosity function (LF) of BL Lac objects from their radio LF. Our derived gamma-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei (AGN) sample. We find that about 45% of the extragalactic diffuse gamma-ray background (EGRB) is contributed by BL Lac objects. Combining the estimate of the quasar contri...

  3. BL Lacertae objects and the extragalactic γ-ray background

    Institute of Scientific and Technical Information of China (English)

    Fan Li; Xin-Wu Cao

    2011-01-01

    A tight correlation between γ-ray and radio emission is found for a sample of BL Lacertae (BL Lac) objects detected by the Fermi Gamma-ray Space Telescope (Fermi) and the Energetic Gamma-Ray Experiment Telescope (EGRET).The γ-ray emission of BL Lac objects exhibits strong variability,and the detection rate of γ-ray BL Lac objects is low,which may be related to the γ-ray duty cycle of BL Lac objects.We estimate the γ-ray duty cycle,δγ (≌)0.11,for BL Lac objects detected by EGRET and Fermi.Using the empirical relation ofγ-ray emission with radio emission and the estimated γ-ray duty cycle δγ,we derive the γ-ray luminosity function (LF) of BL Lac objects from their radio LF.Our derived γ-ray LF of BL Lac objects can almost reproduce that calculated with the recently released Fermi bright active galactic nuclei (AGN) sample.Comparison of the derived LF of the γ-ray BL Lac objects in this work with that derived by Abdo et al.(2009a) requires the γ-ray duty cycle of BL Lac objects to be almost luminosity-independent.We find that ~ 45% of the extragalactic diffuse γ-ray background (EGRB) is contributed by BL Lac objects.Combining the estimate of the quasar contribution to the EGRB in the previous work,we find that ~ 77% of the EGRB is contributed by BL Lac objects and radio quasars.

  4. Relativistic Beaming and Orientation Effects in BL Lacertae Objects

    Indian Academy of Sciences (India)

    F. C. Odo; A. A. Ubachukwu; A. E. Chukwude

    2012-09-01

    We use the correlation between the core-to-lobe radio luminosity ratio () and the linear size () of a sample of BL Lacertae objects to investigate the relativistic beaming and radio source orientation paradigm for high peaked and low-peaked BL Lacs (X-ray and radio selected BL Lacs respectively) and to constrain relativistic beaming model for this extreme class of active galactic nuclei. We show that the - distributions of the BL Lac populations contradict blazar orientation sequence, with the X-ray selected BL Lacs (XBLs) being more consistent with the beaming and orientation model. On the premise that Fanaroff-Riley Type I radio galaxies are the unbeamed parent population of these objects, we derive the bulk Lorentz factor of the jets, ∼ 7-20 corresponding to a critical cone angle for optimum boosting, c of ∼ 1° - 4°, while on average, these objects are inclined at 5° - 12° to the line-of-sight. The implications of these results for the blazar unification sequence are discussed.

  5. On the relationship between BL Lacertae objects and radio galaxies

    CERN Document Server

    Landt, Hermine

    2008-01-01

    We present deep radio images at 1.4 GHz of a large and complete sample of BL Lacertae objects (BL Lacs) selected from the Deep X-ray Radio Blazar Survey (DXRBS). We have observed 24 northern sources with the Very Large Array (VLA) in both its A and C configurations and 15 southern sources with the Australia Telescope Compact Array (ATCA) in its largest configuration. We find that in the DXRBS, as in the 1-Jy survey, which has a radio flux limit roughly ten times higher than the DXRBS, a considerable number (about a third) of BL Lacs can be identified with the relativistically beamed counterparts of Fanaroff-Riley type II (FR II) radio galaxies. We attribute the existence of FR II-BL Lacs, which is not accounted for by current unified schemes, to an inconsistency in our classification scheme for radio-loud active galactic nuclei (AGN). Taking the extended radio power as a suitable measure of intrinsic jet power, we find similar average values for low- (LBL) and high-energy peaked BL Lacs (HBL), contrary to the...

  6. Infrared Variation of Radio Selected BL Lacertae Objects

    CERN Document Server

    Lin, R G

    1999-01-01

    In this paper, the historical infrared (JHK) data compiled from the published literature are presented in electronic form for 40 radio selected BL Lacertae objects (RBLs) for the first time. Largest variations are found and compared with the largest optical variation. Relations between color index and magnitude and between color-color indices are discussed individually. For the color-magnitude relation, some objects (0048-097, 0735+178, 0851+202, 1215+303, 1219+285, 1749+096, and perhaps 0219+428, 0537-441, 1514-241) show that color index increases with magnitude indicating that the spectrum flattens when the source brightens while some other objects (0754+100, 1147+245, 1418+546, and 1727+502) perhaps show an opposite behaviour, while remaining objects do not show any clear tendency; For color-color relation, it is found common that (J-K) is closely correlated with (J-H) while (J-H) is not correlated with (H-K).

  7. Optical polarimetry and photometry of X-ray selected BL Lacertae objects

    Science.gov (United States)

    Jannuzi, Buell T.; Smith, Paul S.; Elston, Richard

    1993-01-01

    We present the data from 3 years of monitoring the optical polarization and apparent brightness of 37 X-ray-selected BL Lacertae objects. The monitored objects include a complete sample drawn from the Einstein Extended Medium Sensitivity Survey. We confirm the BL Lac identifications for 15 of these 22 objects. We include descriptions of the objects and samples in our monitoring program and of the existing complete samples of BL Lac objects, highly polarized quasars, optically violent variable quasars, and blazars.

  8. A Search for Low-Luminosity BL Lacertae Objects

    Science.gov (United States)

    Rector, Travis A.; Stocke, John T.; Perlman, Eric S.

    1999-05-01

    Many properties of BL Lacs have become explicable in terms of the ``relativistic beaming'' hypothesis, whereby BL Lacs are FR 1 radio galaxies viewed nearly along the jet axis. However, a possible problem with this model is that a transition population between beamed BL Lacs and unbeamed FR 1 galaxies has not been detected. A transition population of ``low-luminosity BL Lacs'' was predicted to exist in abundance in X-ray-selected samples such as the Einstein Extended Medium Sensitivity Survey (EMSS) by Browne & Marcha. However, these BL Lacs may have been misidentified as clusters of galaxies. We have conducted a search for such objects in the EMSS with the ROSAT High-Resolution Imager (HRI) here we present ROSAT HRI images, optical spectra, and VLA radio maps for a small number of BL Lacs that were previously misidentified in the EMSS catalog as clusters of galaxies. While these objects are slightly lower in luminosity than other EMSS BL Lacs, their properties are too similar to the other BL Lacs in the EMSS sample to ``bridge the gap'' between BL Lacs and FR 1 radio galaxies. Also, the number of new BL Lacs found is too low to alter significantly the X-ray luminosity function or value for the X-ray-selected EMSS BL Lac sample. Thus, these observations do not explain fully the discrepancy between the X-ray- and radio-selected BL Lac samples.

  9. A Search for Low-Luminosity BL Lacertae Objects

    CERN Document Server

    Rector, T A; Perlman, E S; Rector, Travis A.; Stocke, John T.; Perlman, Eric S.

    1999-01-01

    Many properties of BL Lacs have become explicable in terms of the "relativistic beaming" hypothesis whereby BL Lacs are FR-1 radio galaxies viewed nearly along the jet axis. However, a possible problem with this model is that a transition population between beamed BL Lacs and unbeamed FR-1s has not been detected. A transition population of "low-luminosity BL Lacs" was predicted to exist in abundance in X-ray-selected samples such as the Einstein Extended Medium Sensitivity Survey (EMSS) by Browne & Marcha. However, these BL Lacs may have been misidentified as clusters of galaxies. We have conducted a search for such objects in the EMSS with the ROSAT HRI; and here we present ROSAT HRI images, optical spectra and VLA radio maps for a small number of BL Lacs which were previously misidentified in the EMSS catalog as clusters of galaxies. While these objects are slightly lower in luminosity than other EMSS BL Lacs, their properties are too similar to the other BL Lacs in the EMSS sample to "bridge the gap" b...

  10. 37 GHz observations of a large sample of BL Lacertae objects

    CERN Document Server

    Nieppola, E; Lähteenmäki, A; Valtaoja, E; Hakala, T; Hovatta, T; Kotiranta, M; Nummila, S; Ojala, T; Parviainen, M; Ranta, M; Saloranta, P -M; Torniainen, I; Tröller, M; 10.1086/512609

    2009-01-01

    We present 37 GHz data obtained at Metsahovi Radio Observatory in 2001 December - 2005 April for a large sample of BL Lacertae objects. We also report the mean variability indices and radio spectral indices in frequency intervals 5 - 37 GHz and 37 - 90 GHz. Approximately 34 % of the sample was detected at 37 GHz, 136 BL Lacertae objects in all. A large majority of the detected sources were low-energy BL Lacs (LBLs). The variability index values of the sample were diverse, the mean fractional variability of the sample being \\Delta S_2 = 0.31. The spectral indices also varied widely, but the average radio spectrum of the sample sources is flat. Our observations show that many of the high-energy BL Lacs (HBL), which are usually considered radio-quiet, can at times be detected at 37 GHz.

  11. The connection between black hole mass and Doppler boosted emission in BL Lacertae type objects

    OpenAIRE

    Leon-Tavares, J.; Valtaoja, E.; V. H. Chavushyan; Tornikoski, M.; Anorve, C.; Nieppola, E.; Lahteenmaki, A.

    2010-01-01

    We investigate the relationship between black hole mass (MBH) and Doppler boosted emission for BL Lacertae type objects (BL Lacs) detected in the SDSS and FIRST surveys. The synthesis of stellar population and bidimensional decomposition methods allows us to disentangle the components of the host galaxy from that of the nuclear black hole in their optical spectra and images, respectively. We derive estimates of black hole masses via stellar velocity dispersion and bulge luminosity. We find th...

  12. Long-Term Optical Spectra Variability of BL Lacertae Object S5 0716+714

    Indian Academy of Sciences (India)

    Zhang Hao Jing; Zhao Gang; Zhang Xiong; Bai Jing Ming; Tang Ling; Xu Yun Bing

    2011-03-01

    Based on the long-term data from observations, we present an evidence for its spectral index variability behaviour in optical bands for BL Lacertae object S5 0716+714.We find that the spectral index variability period is in agreement with the flux variability period of about 1180 days in optical bands.We also find that the spectral index variability has periods of about 71 and 60 days which cannot be compared with the amplitude of long-term variability.

  13. Broad Ly alpha Emission from Three Nearby BL Lacertae Objects

    CERN Document Server

    Stocke, John T; Perlman, Eric S

    2011-01-01

    We present far-UV HST/COS spectra of four nearby BL Lac Objects. BL Lac spectra are dominated by a smooth, power-law continuum which arises in a relativistic jet. However, the spectra are not necessarily featureless; weak, broad- and/or narrow-line emission is sometimes seen in high-quality optical spectra. We present detections of Lya emission in HST/COS spectra of Mrk421 (z=0.030) and PKS2005-489 (z=0.071) as well as an archival HST/GHRS observation of Mrk501 (z=0.0337). Archival HST/STIS observations of PKS2155-304 (z=0.116) show no Lya emission to a very low upper limit. Using the assumption that the broad-line region (BLR) clouds are asymmetrically placed around the AGN, we use these measured Lya emission features to constrain either the relativistic Gamma values for the ionizing continuum produced by the jet (in the ionization-bounded case) or the mass of warm gas (in the density-bounded case). While realistic Gamma values can be obtained for all four cases, the values for Mrk421 and PKS2155-304 are hig...

  14. Simultaneous observations of the BL Lacertae object I Zw 187

    Science.gov (United States)

    Bregman, J. N.; Glassgold, A. E.; Huggins, P. J.; Pollock, J. T.; Pica, A. J.; Smith, A. G.; Webb, J. R.; Ku, W. H.-M.; Rudy, R. J.; Levan, P. D.

    1982-01-01

    Two sets of simultaneous spectra consisting of data obtained with radio, IR, optical, UV and X-ray telescopes were obtained 10 months apart for the X-ray bright BL Lac object IZw 187. In addition, nonsimultaneous observations were made in several of the aforementioned observing bands in order to detect flux variations and galactic light contamination was removed from all observations. The BL Lac component is found to have a weak 3000 A bump superposed on an IR-optical-UV spectrum of slope 0.9. Consistent with the arising of the IR-through-X-ray continuum from a single synchrotron source, the X-ray data fall on or near an extrapolation of this power law. No flux variations have been detected in the flat radio spectrum. Optical and X-ray fluxes are observed to vary by a factor not greater than three, and the shortest variability time scales in these bands are comparable at about one week.

  15. Simultaneous multifrequency observations of the BL Lacertae object Markarian 421

    Science.gov (United States)

    Makino, F.; Tanaka, Y.; Matsuoka, M.; Koyama, K.; Inoue, H.; Makishima, K.; Hoshi, R.; Hayakawa, S.; Kondo, Y.

    1987-01-01

    Simultaneous multifrequency observations of the BL Lac object Mrk 421 covering radio through X-ray wavelengths were performed on two occasions separated by 5 weeks in January and March 1984, and each observation was coordinated for about 1 week. Composite multifrequency spectra of the central nonthermal component were obtained at the two epochs after subtracting the optical and infrared light of the underlying galaxy. The spectra show the gradual steepening toward high frequency; the power law indices are about 0.1, about 0.6, and about 1.0 for radio, infrared-optical, and UV bands, respectively. The UV and optical-infrared fluxes decreased by about 20 percent in 5 weeks, while the radio flux remained stable. The X-ray flux decreased by a factor of about 2, and the change was more pronounced at hard X-rays, which suggest that X-ray emission possibly consists of two components. The degree of polarization at the optical band varied on the time scale of a few days, while the position angle remained unchanged. Physical parameters of Mrk 421 are discussed in terms of the synchrotron self-Compton model.

  16. Effects of Redshift on the Classifying Criteria of BL Lacertae Objects

    Institute of Scientific and Technical Information of China (English)

    Li Ma; Luo-En Chen; Guang-Zhong Xie; Ji-Yang Ren; Zhao-Hua Xie; Shu-Bai Zhou; Hui Wu; Dong-Cheng Mei

    2007-01-01

    We have collected a sample of 70 BL Lacs(33 radio-selected BL Lacs and 37 X-ray selected BL Lacs) with multi-waveband data for investigating the classifying criteria of BL Lacertae Objects.For each source,we estimate its luminosities in radio.optical and X-ray,the broad-band spectral index from radio to X-ray and the peak frequency of the synchrotron emission,and make a statistical analysis of the data obtained.Our main results are as follows:(1)The broad-band spectral index and the peak frequency have no correlation with the redshift.while they are inversely correlated with each other and they could be regarded as equivalent classifying criteria of BL Lac objects.(2)There are significant effects of the luminosity/redshift relation on the observed luminosity distribution in our sample,hence,if the radio luminosity is to be used as a classifying criterion of BL Lac objects.it should not be regarded as equivalent to the broad-band spectral index or the peak frequency.(3)Our results supply a specific piece of evidence for the suggestion that the use of luminosities always introduces a redshift bias to the data and show that the location of the peak frequency is not always linked to the luminosity of any wave band.

  17. Fanaroff-Riley I galaxies as the parent population of BL Lacertae objects. I. X-ray constraints

    Energy Technology Data Exchange (ETDEWEB)

    Padovani, P.; Urry, C.M. (Space Telescope Science Institute, Baltimore, MD (USA))

    1990-06-01

    The hypothesis that BL Lacertae objects are a special subset of Fanaroff-Riley type I radio galaxies, namely, those dominated by beamed emission from a relativistic jet aligned with the line of sight, is examined by looking at the relative number densities. The calculation depends primarily on observed quantities, including the X-ray luminosity function of Fanaroff-Riley type I galaxies. The model predicts the X-ray luminosity function of BL Lacertae objects, the shape of the X-ray counts below currently observed fluxes, and the velocity of the X-ray emitting jet. With Fanaroff-Riley type I galaxies as the parent population the flat luminosity function, the observed X-ray number counts, and the partial redshift distribution of BL Lacertae objects can be explained. 41 refs.

  18. Filling the Infrared Gap: ISO Observations of 1 Jy BL Lacertae Objects

    CERN Document Server

    Padovani, P; Abraham, P; Csizmadia, S; Moor, A

    2006-01-01

    The large majority of BL Lacertae objects belonging to the 1 Jy sample, the class prototype for radio-selected sources, are thought to emit most of their synchrotron power in the far IR band. Ironically, this spectral region is very sparsely sampled, with only a minority of the objects having IRAS data (most of them being upper limits or low-quality detections). We aim at filling this IR gap by presenting new, simultaneous ISOCAM and ISOPHOT observations over the 7 - 200 micron range for half the sample. A measurement of the position of the synchrotron peak frequency, nu_peak, can provide information about particle acceleration mechanisms and constrain the inverse Compton radiation that will be detected by up-coming new gamma-ray missions. We have observed 17 1 Jy BL Lacertae objects with the camera and the photometer on board the Infrared Space Observatory (ISO) satellite. The ISOPHOT data reduction was done employing a novel correction, which mitigates the effect of chopping for faint sources. Using our new...

  19. VERITAS and Multiwavelength Observations of the BL Lacertae Object 1ES 1741+196

    CERN Document Server

    Abeysekara, A U; Archer, A; Benbow, W; Bird, R; Biteau, J; Buchovecky, M; Buckley, J H; Bugaev, V; Byrum, K; Cardenzana, J V; Cerruti, M; Chen, X; Christiansen, J L; Ciupik, L; Connolly, M P; Cui, W; Dickinson, H J; Dumm, J; Eisch, J D; Errando, M; Falcone, A; Feng, Q; Finley, J P; Fleischhack, H; Flinders, A; Fortin, P; Fortson, L; Furniss, A; Gillanders, G H; Griffin, S; Grube, J; Gyuk, G; Hütten, M; Hanna, D; Holder, J; Humensky, T B; Johnson, C A; Kaaret, P; Kar, P; Kelley-Hoskins, N; Kertzman, M; Kieda, D; Krause, M; Krennrich, F; Kumar, S; Lang, M J; Maier, G; McArthur, S; McCann, A; Meagher, K; Moriarty, P; Mukherjee, R; Nieto, D; O'Brien, S; de Bhróithe, A O'Faoláin; Ong, R A; Otte, A N; Park, N; Pelassa, V; Petrashyk, A; Pohl, M; Popkow, A; Pueschel, E; Quinn, J; Ragan, K; Ratliff, G; Reyes, L C; Reynolds, P T; Richards, G T; Roache, E; Rulten, C; Santander, M; Sembroski, G H; Shahinyan, K; Smith, A W; Staszak, D; Telezhinsky, I; Tucci, J V; Tyler, J; Vincent, S; Wakely, S P; Weiner, O M; Weinstein, A; Wilhelm, A; Williams, D A; Zitzer, B

    2016-01-01

    We present results from multiwavelength observations of the BL Lacertae object 1ES 1741+196, including results in the very-high-energy $\\gamma$-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well-modelled by a power law with a spectral index of $2.7\\pm0.7_{\\mathrm{stat}}\\pm0.2_{\\mathrm{syst}}$. The integral flux above 180 GeV is $(3.9\\pm0.8_{\\mathrm{stat}}\\pm1.0_{\\mathrm{syst}})\\times 10^{-8}$ m$^{-2}$ s$^{-1}$, corresponding to 1.6% of the Crab Nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state.

  20. VERITAS and multiwavelength observations of the BL Lacertae object 1ES 1741+196

    Science.gov (United States)

    Abeysekara, A. U.; Archambault, S.; Archer, A.; Benbow, W.; Bird, R.; Biteau, J.; Buchovecky, M.; Buckley, J. H.; Bugaev, V.; Byrum, K.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Christiansen, J. L.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Flinders, A.; Fortin, P.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Grube, J.; Gyuk, G.; Huetten, M.; Hanna, D.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kelley-Hoskins, N.; Kertzman, M.; Kieda, D.; Krause, M.; Krennrich, F.; Lang, M. J.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Moriarty, P.; Mukherjee, R.; Nieto, D.; O'Brien, S.; O'Faoláin de Bhróithe, A.; Ong, R. A.; Otte, A. N.; Park, N.; Pelassa, V.; Petrashyk, A.; Petry, D.; Pohl, M.; Popkow, A.; Pueschel, E.; Quinn, J.; Ragan, K.; Ratliff, G.; Reyes, L. C.; Reynolds, P. T.; Reynolds, K.; Richards, G. T.; Roache, E.; Rulten, C.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Vincent, S.; Wakely, S. P.; Weiner, O. M.; Weinstein, A.; Wilhelm, A.; Williams, D. A.; Zitzer, B.

    2016-07-01

    We present results from multiwavelength observations of the BL Lacertae object 1ES 1741 + 196, including results in the very high energy γ-ray regime using the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The VERITAS time-averaged spectrum, measured above 180 GeV, is well modelled by a power law with a spectral index of 2.7 ± 0.7stat ± 0.2syst. The integral flux above 180 GeV is (3.9 ± 0.8stat ± 1.0syst) × 10-8 m-2 s-1, corresponding to 1.6 per cent of the Crab nebula flux on average. The multiwavelength spectral energy distribution of the source suggests that 1ES 1741+196 is an extreme-high-frequency-peaked BL Lacertae object. The observations analysed in this paper extend over a period of six years, during which time no strong flares were observed in any band. This analysis is therefore one of the few characterizations of a blazar in a non-flaring state.

  1. BL Lacertae objects and radio-loud quasars within an evolutionary unified scheme

    Energy Technology Data Exchange (ETDEWEB)

    Vagnetti, F.; Cavaliere, A.; Giallongo, E. (Roma II Universita, Rome (Italy) Roma Osservatorio Astronomico, Rome (Italy))

    1991-02-01

    On the basis of a joint radio-optical analysis, different amounts of cosmological luminosity evolution in the optical band for flat- and steep-spectrum radio-loud quasars are found. Specifically, a slower evolution for the flat-spectrum quasars, evidence of a sluggish beamed component in the optical band additional to the canonical isotropic continuum is shown. The persistence of the beamed component in terms of a spectral evolution with the Doppler factor increasing somewhat in cosmic time is interpreted. The BL Lacertae objects are placed into this framework and an evolutionary unified scheme is proposed maintaining spectral and statistical continuity of BL Lacs with flat-spectrum quasars. Supportive observational evidence, and clues for the parent population, are discussed. 57 refs.

  2. Fanaroff-Riley I galaxies as the parent population of BL Lacertae objects. II - Optical constraints

    Energy Technology Data Exchange (ETDEWEB)

    Padovani, P.; Urry, C.M. (Space Telescope Science Institute, Baltimore, MD (USA))

    1991-02-01

    The hypothesis is investigated that BL Lacertae objects are a subset of Fanaroff-Riley (FR) I galaxies dominated by beamed emission from a relativistic jet aligned with the line of sight. It is found that FR I galaxies, although of low radio luminosity, are bright optical galaxies. If the beaming hypothesis is correct, the optical luminosity function of BL Lac objects, including the effect of the host galaxy, can be approximated by a double power law with a given differential index. New estimates of the number counts of BL Lac objects are made which constrain their local number density for L(B) greater than about 6 x 10 to the 43rd ergs/s to be in the range 110-720/cu Gpc. The corresponding ratio between the total number densities of BL Lac objects and FR I galaxies is 0.003 to 0.02. This limits the Lorentz factor of the optical emission to the range 8-20, larger than that of the X-ray emitting plasma and roughly of the same order as the radio Lorentz factor. 34 refs.

  3. Optical polarimetry of PKS 2155 - 304 and constraints on accretion disk models for BL Lacertae objects

    Science.gov (United States)

    Smith, Paul S.; Sitko, Michael L.

    1991-01-01

    Optical broad-band polarimetry and photometry of the BL Lacertae object PKS 2155 - 304 during late 1990 are presented. Variability in both flux and linear polarization was moderate during this period. The optical polarization ranged from 2 to 7 percent while photometric variations were within 0.2 mag (V = 13.2-13.4). Accurate multicolor measurements were made to study any wavelength dependence of the polarization with an eye to using these data to test the model of Wandel and Urry (1991) which proposes that the UV to soft X-ray continuum of this object arises from an accretion disk. Wavelength-dependent polarization (WDP) is observed in PKS 2155 - 304. However, the polarization is always seen to decrease with wavelength when WDP is observed. This is opposite to the expected sense of WDP if the UV continuum is dominated by an accretion disk.

  4. The Hubble Space Telescope Survey of BL Lacertae Objects. IV. Infrared Imaging of Host Galaxies

    Science.gov (United States)

    Scarpa, Riccardo; Urry, C. Megan; Padovani, Paolo; Calzetti, Daniela; O'Dowd, Matthew

    2000-11-01

    The Hubble Space Telescope NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with the WFPC2 in the R band by Urry and coworkers and Scarpa and coworkers. Ten of the 12 BL Lacs are clearly resolved, and the detected host galaxies are large, bright ellipticals with average absolute magnitude =-26.2+/-0.45 mag and effective radius =10+/-5 kpc. The rest-frame integrated color of the host galaxies is on average =2.3+/-0.3, consistent with the value for both radio galaxies and normal, nonactive elliptical galaxies and indicating that the dominant stellar population is old. The host galaxies tend to be bluer in their outer regions than in their cores, with average color gradient Δ(R-H)/Δlogr=-0.2 mag, again consistent with results for normal nonactive elliptical galaxies. The infrared Kormendy relation, derived for the first time for BL Lac host galaxies, is μe=3.8logre+14.8, fully in agreement with the relation for normal ellipticals. The close similarity between BL Lac host galaxies and normal ellipticals suggests that the active nucleus has surprisingly little effect on the host galaxy. This supports a picture in which all elliptical galaxies harbor black holes that can be actively accreting for some fraction of their lifetime.

  5. The Binary Black Hole Scenario for the BL Lacertae Object AO 0235+16

    Institute of Scientific and Technical Information of China (English)

    G. E. Romero; Jun-Hui Fan; S. E. Nuza

    2003-01-01

    Recent analysis of the long term radio light curve of the extremely variable BL Lacertae object AO 0235t16 by Raiteri et al. have revealed the presence of recurrent outbursts with a period of ~ 5.7 ± 0.5yr. Periodicity analysis of the optical light curve also shows evidence for a shorter period. Here we discuss whether such a behavior can be explained by a binary black hole model where the accretion disk of one of the supermassive black holes is precessing due to the tidal effects of the companion. We estimate the mass of the accreting hole and analyze constraints on the secondary mass and the orbital parameters of the system. It is possible to provide a viable interpretation of the available multiwavelength data.

  6. The HST Survey of BL~Lacertae Objects. IV. Infrared Imaging of Host Galaxies

    CERN Document Server

    Scarpa, R; Padovani, P; O'Dowd, M; Scarpa, Riccardo; Padovani, Paolo; O'Dowd, Matthew; Calzetti, Daniela

    2000-01-01

    The HST NICMOS Camera 2 was used for H-band imaging of 12 BL Lacertae objects taken from the larger sample observed with the WFPC2 in the R band (Urry et al. 2000; Scarpa et al. 2000). Ten of the 12 BL Lacs are clearly resolved, and the detected host galaxies are large, bright ellipticals with average H-band absolute magnitude M=-26.2+-0.45 mag and effective radius 10+-5 kpc. The rest-frame integrated color of the host galaxies is on average R-H=2.3+-0.3, consistent with the value for both radio galaxies and normal, non-active elliptical galaxies, and indicating the dominant stellar population is old. The host galaxies tend to be bluer in their outer regions than in their cores, with average color gradient Delta(R-H)/Delta(log r)=-0.2 mag, again consistent with results for normal non-active elliptical galaxies. The infrared Kormendy relation, derived for the first time for BL Lac host galaxies, is m(e) = 3.8*log(R)+14.8 (where m(e) is the surface brightness at the effective radius R), fully in agreement with ...

  7. Constraints on the Very High Energy Emission from BL Lacertae Objects

    CERN Document Server

    Horan, D; Bond, I H; Boyle, P J; Bradbury, S M; Buckley, J H; Carter-Lewis, A; Catanese, M; Celik, O; Cui, W; Daniel, M; D'Vali, M; dela Calle, I; Perez; Duke, C; Falcone, A; Fegan, D J; Fegan, S J; Finley, J P; Fortson, L F; Gaidos, A; Gammell, S; Gibbs, K; Gillanders, G H; Grube, J; Hall, J; Hall, T A; Hanna, D; Hillas, A M; Holder, J; Jarvis, A; Jordan, M; Kenny, G E; Kertzman, M; Kieda, D; Kildea, J; Knapp, J; Kosack, K; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Linton, E T; Lloyd-Evans, J; Milovanovic, A; Moriarty, P; Müller, D; Nagai, T; Nolan, S J; Ong, R A; Pallassini, R; Petry, D; Power-Mooney, B; Quinn, J; Quinn, M; Ragan, K; Rebillot, P; Reynolds, P T; Rose, J H; Schroedter, M; Sembroski, G H; Swordy, S P; Syson, A; Vasilev, V V; Wakely, S P; Walker, G; Weekes, T C; Zweerink, J

    2003-01-01

    We present results from observations of 29 BL Lacertae objects, taken with the Whipple Observatory 10 m Gamma-Ray Telescope between 1995 and 2000. The observed objects are mostly at low redshift (z < 0.2) but observations of objects of z up to 0.444 are also reported. Five of the objects are EGRET sources and two are unconfirmed TeV sources. Three of the confirmed sources of extragalactic TeV gamma rays were originally observed as part of this survey and have been reported elsewhere. No significant excesses are detected from any of the other objects observed, on time scales of days, months or years. We report 99.9% confidence level flux upper limits for the objects for each observing season. The flux upper limits are typically 20% of the Crab flux although, for some sources, limits as sensitive as 6% of the Crab flux were derived. The results are consistent with the synchrotron-self-Compton (SSC) model predictions considered in this work.

  8. Optically Identified BL Lacertae Objects From the Sloan Digital Sky Survey

    Science.gov (United States)

    2007-11-02

    386 BL Lacertae candidates identified from 2860 deg2 of the Sloan Digital Sky Survey ( SDSS ) spectroscopic database. The candidates are primarily...selected to have quasi-featureless optical spectra and low proper motions as measured from SDSS and USNO-B positions; however, our ability to separate...Sky Survey ( SDSS ; York et al. 2000) and the Two-Degree Field QSO Red- shift Survey (2QZ; Boyle et al. 2000), have the potential to reveal new

  9. Six-year Optical Monitoring of BL Lacertae Object 1ES 0806+52.4

    CERN Document Server

    Man, Zhongyi; Wu, Jianghua; Zhou, Xu; Yuan, Qirong

    2014-01-01

    We present the results of the first systematic long-term multi-color optical monitoring of the BL Lacertae object 1ES 0806+52.4. The monitoring was performed in multiple passbands with a 60/90 cm Schmidt telescope from December 2005 to February 2011. The overall brightness of this object decreased from 2005 December to 2008 December, and regained after that. A sharp outburst probably occurred around the end of our monitoring program. Overlapped on the long-term trend are some short-term small-amplitude oscillations. No intra-night variability was found in the object, which is in accord with the historical observations before 2005. By investigating the color behavior, we found strong bluer-when-brighter chromatism for the long-term variability of 1ES 0806+52.4. The total amplitudes at the c, i and o bands are 1.18, 1.12, and 1.02 mags, respectively. The amplitudes tend to increase toward shorter wavelength, which may be the major cause of bluer-when-brighter. Such bluer-when-brighter is also found in other bla...

  10. Simultaneous optical monitoring of BL Lacertae object S5 0716+714 with high temporal resolution

    CERN Document Server

    Man, Zhongyi; Wu, Jianghua; Yuan, Qirong

    2015-01-01

    We have monitored the BL Lacertae object S5 0716+714 simultaneously in the B, R and I bands on three nights in November 2014. The average time resolution is quite high (73s, 34s, 58s for the filters B, R and I), which can help us trace the profile of the variation and search for the short inter-band time delay. Intra-day variability was about 0.1 mag on the first two nights and more than 0.3 mag on the third. A bluer-when-brighter color behavior was found. An clear loop path can be seen on the color-magnitude diagram of the third night, revealing possible time delays between variations at high and low energies. It is the first time that the intra-day spectral hysteresis loop has been found so obviously in the optical band. We used the interpolated cross-correlation function method to further confirm the time delay and calculated the values of lag between light curves at different wavelengths on each night. On the third night, variations in the R and B bands is approximately 1.5 minutes lagging behind the I ba...

  11. Simultaneous optical monitoring of BL Lacertae object S5 0716+714 with high temporal resolution

    Science.gov (United States)

    Man, Zhongyi; Zhang, Xiaoyuan; Wu, Jianghua; Yuan, Qirong

    2016-03-01

    We have monitored the BL Lacertae object S5 0716+714 simultaneously in the B, R and I bands on three nights in 2014 November. The average time resolution is quite high (73, 34 and 58 s for the filters B, R and I), which can help us trace the profile of the variation and search for the short inter-band time delay. Intra-day variability was about 0.1 mag on the first two nights and more than 0.3 mag on the third. A bluer-when-brighter colour behaviour was found. A clear loop path can be seen on the colour-magnitude diagram of the third night, revealing possible time delays between variations at high and low energies. It is the first time that the intra-day spectral hysteresis loop has been found so obviously in the optical band. We used the interpolated cross-correlation function method to further confirm the time delay and calculated the values of lag between light curves at different wavelengths on each night. On the third night, variations in the R and B bands are approximately 1.5 min lagging behind the I band. Such optical time delay is probably due to the interplay of different processes of electrons in the jet of the blazar.

  12. Short Timescale Photometric and Polarimetric Behavior of two BL Lacertae Type Objects

    CERN Document Server

    Covino, S; Foschini, L; Sandrinelli, A; Tavecchio, F; Treves, A; Zhang, H; de Almeida, U Barres; Bonnoli, G; Boettcher, M; Cecconi, M; D'Ammando, F; di Fabrizio, L; Giarrusso, M; Leone, F; Lindfors, E; Lorenzi, V; Molinari, E; Paiano, S; Prandini, E; Raiteri, C M; Stamerra, A; Tagliaferri, G

    2015-01-01

    Blazars are astrophysical sources whose emission is dominated by non-thermal processes, typically interpreted as synchrotron and inverse Compton emission. Although the general picture is rather robust and consistent with observations, many aspects are still unexplored. Polarimetric monitoring can offer a wealth of information about the physical processes in blazars. Models with largely different physical ingredients can often provide almost indistinguishable predictions for the total flux, but usually are characterized by markedly different polarization properties. We explore, with a pilot study, the possibility to derive structural information about the emitting regions of blazars by means of a joint analysis of rapid variability of the total and polarized flux at optical wavelengths. Short timescale (from tens of seconds to a couple of minutes) optical linear polarimetry and photometry for two blazars, BL Lacertae and PKS 1424+240, was carried out with the PAOLO polarimeter at the 3.6m Telescopio Nazionale ...

  13. Ultraviolet polarimetry and spectroscopy of the BL Lacertae object PKS 2155-304

    Science.gov (United States)

    Allen, Richard G.; Smith, Paul S.; Angel, J. R. P.; Miller, Bryan W.; Anderson, Scott F.; Margon, Bruce

    1993-01-01

    HST and Faint Object Spectrograph spectropolarimetry is presented for the BL Lac object PKS 2155-304; attention is given to the wavelength dependence of the UV linear polarization in a BL Lac object. The UV polarimetry yields evidence that the UV polarized flux is generated by the synchrotron mechanism responsible for optical polarization. Both the UV and optical emission are produced in the same region of the source.

  14. Discovery of >350 GeV Gamma Rays from the BL Lacertae Object 1ES 2344+514

    CERN Document Server

    Catanese, M; Badran, H M; Biller, S D; Bond, I H; Boyle, P J; Bradbury, S M; Buckley, J H; Burdett, A M; Gordo, J B; Carter-Lewis, D A; Cawley, M F; Connaughton, V; Fegan, D J; Finley, J P; Gaidos, J A; Hall, T; Hillas, A M; Krennrich, F; Lamb, R C; Lessard, R W; Masterson, C; McEnery, J E; Mohanty, G B; Quinn, J; Rodgers, A J; Rose, H J; Samuelson, F W; Schubnell, M S; Sembroski, G H; Srinivasan, R; Weekes, T C; Wilson, C W; Zweerink, J A

    1997-01-01

    We present the discovery of >350 GeV gamma-ray emission from the BL Lacertae object 1ES 2344+514 with the Whipple Observatory 10m gamma-ray telescope. This is the third BL Lac object detected at gamma-ray energies above 300 Gev, the other two being Markarian 421 (Mrk 421) and Mrk501. These three active galactic nuclei are all X-ray selected and have the lowest known redshifts of any BL Lac objects currently identified. The evidence for emission derives primarily from an apparent flare on December 20, 1995 when a 6 sigma excess was detected with a flux approximately 63% of the very high energy gamma-ray emission from the Crab Nebula, the standard candle for TeV gamma-ray sources. Excluding the flare, observations between October 1995 and January 1996 yield a 4 sigma detection corresponding to 11% of the VHE Crab Nebula flux. Observations spanning September 1996 to January 1997 failed to yield a significant detection of a steady flux or any flaring. For this period, the 99.9% confidence level upper limit is <...

  15. Determining the nature of orbits in a three-dimensional galaxy model hosting a BL Lacertae object

    CERN Document Server

    Zotos, Euaggelos E

    2014-01-01

    A three-dimensional dynamical model for a galaxy hosting a BL Lacertae object is constructed. The model consists of a logarithmic potential representing an elliptical host galaxy with a bulge of radius $c_b$ and a dense massive nucleus. Using numerical experiments, we try to distinguish between regular and chaotic motion in both 2D and 3D system. In particular, we investigate how the basic parameters of our model, such as the mass of the nucleus, the internal perturbation and the flattening parameters influence the amount and the degree of chaos. Interesting correlations are presented for both 2D and 3D dynamical models. Our numerical results are explained and supported using elementary theoretical arguments and analytical calculations. Of particular interest, is the local integral of motion which have been found to exist in the vicinity of stable periodic points. The obtained numerical outcomes of the present research, are linked and also compared with several data derived from observations.

  16. Radio outburst of BL Lacertae

    Science.gov (United States)

    Buemi, C. S.; Leto, P.; Trigilio, C.; Umana, G.; Giroletti, M.; Orienti, M.; Raiteri, C. M.; Villata, M.; Bach, U.

    2013-04-01

    We report on extremely high radio flux of BL Lacertae at 43 and 8 GHz. Observations at 43 GHz with the 32 m radio telescope in Noto (Italy) revealed a flux density of 10.5 +/- 0.2 Jy on 2013 April 10.65, while observations at 8 GHz with the 32 m radio telescope in Medicina (Italy) detected a flux density of 8.2 +/- 0.7 Jy on April 12.22. These extremely high radio fluxes show that the radio activity likely correlated to the strong optical, near-infrared, and gamma-ray activity of 2011-2012 (see ATels #4028, #4031, #4155, #4271, #4277, #4349, #4565, #4600), and X-ray activity of late 2012 (ATels #4557, #4627), is far to be exhausted.

  17. The Lack of Torus Emission from BL Lacertae Objects: An Infrared View of Unification with WISE

    CERN Document Server

    Plotkin, Richard M; Brandt, W N; Markoff, Sera; Shemmer, Ohad; Wu, Jianfeng

    2011-01-01

    We use data from the Wide-Field Infrared Survey Explorer (WISE) to perform a statistical study on the mid-infrared (IR) properties of a large number ($\\sim10^2$) of BL Lac objects --- low-luminosity Active Galactic Nuclei (AGN) with a jet beamed toward the Earth. As expected, many BL Lac objects are so highly beamed that their jet synchrotron emission dominates their IR spectral energy distributions. In other BL Lac objects, however, the jet is not strong enough to completely dilute the rest of the AGN emission. We do not see observational signatures of the dusty torus from these weakly beamed BL Lac objects. The lack of observable torus emission is consistent with suggestions that BL Lac objects are fed by radiatively inefficient accretion disks. Implications for the "nature vs. nurture" debate for FR I and FR II radio galaxies are briefly discussed. Our study supports the notion that, beyond orientation, accretion rate plays an important role in AGN unification.

  18. A ubiquitous absorption feature in the X-ray spectra of BL Lacertae objects

    Science.gov (United States)

    Madejski, Greg M.; Mushotzky, Richard F.; Weaver, Kimberly A.; Arnaud, Keith A.; Urry, C. Megan

    1991-01-01

    The paper presents the broadband (0.5-20-keV) X-ray spectra of five X-ray bright BL Lac objects observed with the Einstein Observatory Solid State Spectrometer (SSS) and Monitor Proportional Counter (MPC) detectors. The combination of moderate energy resolution and broad spectral coverage makes it possible to confirm the presence of an absorption feature at an energy of 650 eV in the BL Lac object PKS 2155-304, originally reported by Canizares and Kruper (1984) based on higher resolution Einstein Objective Grating Spectrometer (OGS) data.

  19. Soft X-Ray Observations of a Complete Sample of X-Ray--selected BL Lacertae Objects

    Science.gov (United States)

    Perlman, Eric S.; Stocke, John T.; Wang, Q. Daniel; Morris, Simon L.

    1996-01-01

    We present the results of ROSAT PSPC observations of the X-ray selected BL Lacertae objects (XBLs) in the complete Einstein Extended Medium Sensitivity Survey (EM MS) sample. None of the objects is resolved in their respective PSPC images, but all are easily detected. All BL Lac objects in this sample are well-fitted by single power laws. Their X-ray spectra exhibit a variety of spectral slopes, with best-fit energy power-law spectral indices between α = 0.5-2.3. The PSPC spectra of this sample are slightly steeper than those typical of flat ratio-spectrum quasars. Because almost all of the individual PSPC spectral indices are equal to or slightly steeper than the overall optical to X-ray spectral indices for these same objects, we infer that BL Lac soft X-ray continua are dominated by steep-spectrum synchrotron radiation from a broad X-ray jet, rather than flat-spectrum inverse Compton radiation linked to the narrower radio/millimeter jet. The softness of the X-ray spectra of these XBLs revives the possibility proposed by Guilbert, Fabian, & McCray (1983) that BL Lac objects are lineless because the circumnuclear gas cannot be heated sufficiently to permit two stable gas phases, the cooler of which would comprise the broad emission-line clouds. Because unified schemes predict that hard self-Compton radiation is beamed only into a small solid angle in BL Lac objects, the steep-spectrum synchrotron tail controls the temperature of the circumnuclear gas at r ≤ 1018 cm and prevents broad-line cloud formation. We use these new ROSAT data to recalculate the X-ray luminosity function and cosmological evolution of the complete EMSS sample by determining accurate K-corrections for the sample and estimating the effects of variability and the possibility of incompleteness in the sample. Our analysis confirms that XBLs are evolving "negatively," opposite in sense to quasars, with Ve/Va = 0.331±0.060. The statistically significant difference between the values for X

  20. Optical imaging of the host galaxies of X-ray selected BL Lacertae objects

    CERN Document Server

    Falomo, R

    1999-01-01

    We investigate the properties of the host galaxies of X-ray selected (high frequency peaked) BL Lac objects using a large and homogeneous data set of high spatial resolution R-band observations of 52 BL Lacs in the EMSS and Slew samples. The redshift distribution of the BL Lacs ranges from z = 0.04 to z>0.7, with average and median redshifts z = 0.26 and z = 0.24, respectively. Eight objects are at unknown redshift. We are able to resolve 45 objects out of the 52 BL Lacs. For all the well-resolved sources, we find the host to be a luminous elliptical galaxy. In a few cases a disk is not ruled out but an elliptical model is still preferred. The average absolute magnitude of the host galaxies is = -23.9+-0.6, while the average scale length of the host is = 9+-5 kpc. There is no difference in the host properties between the EMSS and Slew samples. We find a good agreement between the results derived by the surveys of Wurtz et al. (ground-based data) and Urry et al. (HST data), and by our new deeper imaging. The...

  1. H 0323 + 022 - A new BL Lacertae object with extremely rapid variability

    Science.gov (United States)

    Feigelson, E. D.; Bradt, H.; McClintock, J.; Remillard, R.; Urry, C. M.; Tapia, S.; Geldzahler, B.; Johnston, K.; Romanishin, W.; Wehinger, P. A.; Wyckoff, S.; Madejski, G.; Schwartz, D. A.; Thorstensen, J.; Schaefer, B. E.

    1986-03-01

    H0323+022 is a highly variable X-ray source discovered in the HEAO 1 all-sky survey coincident with a 16th mag stellar object. Optical nebulosity around the object strongly suggests that it is a BL Lac object. This paper presents the results of a multiband, multiepoch series of observations that demonstrate beyond reasonable doubt that H0323+022 is a remarkably variable BL Lac object. The optical nebulosity around the stellar object is confirmed, the stellar optical radiation is polarized, and the radio characteristics and the overall electromagnetic spectrum resemble those of other BL Lac objects. Variability is seen in all bands, including radio and broad-band optical variations in days, optical polarization changes on time scales of tens of minutes, and X-ray changes on time scales of ≡30 s. H0323+022 is thus an active galactic nucleus with much of the observed emission emerging from a region ⪉1012 - 1014cm in size.

  2. Synchrotron and Inverse Compton Variability in the BL Lacertae object S5 0716+714

    CERN Document Server

    Giommi, P; Chiappetti, L; Ferrara, E C; Ghisellini, G; Jang, M; Maesano, M; Miller, H R; Montagni, F; Nesci, R; Padovani, P; Perlman, E S; Raiteri, C M; Sclavi, S; Tagliaferri, G; Tosti, G; Villata, M; Jang, Minhwan

    1999-01-01

    We report intensity variations of different spectral components in the BL Lac object S5 0716+714 detected during coordinated BeppoSAX and optical observations in 1996 and 1998. The transition between synchrotron and inverse Compton emission has been clearly detected as sharp X-ray spectral breaks at around 2-3 keV on both occasions. Correlated optical and soft X-ray variability was found during the second BeppoSAX pointing when intensive optical monitoring could be arranged. The hard (Compton) component changed by a factor of 2 between the two observations, but remained stable within each exposure. During events of rapid variability S5 0716+714 showed spectral steepening with intensity, a behaviour rarely observed in BL Lacs. We interpret these findings as the probable consequence of a shift of the synchrotron peak emission from the IR/optical band to higher energies, causing the synchrotron tail to push into the soft X-ray band more and more as the source brightens.

  3. Detection of Lyman continuum absorption in the BL Lacertae object PKS 0735+178

    Science.gov (United States)

    Bregman, J. N.; Glassgold, A. E.; Huggins, P. J.

    1981-01-01

    The detection of the Lyman edge in the BL Lac object PKS 0735+178 at the absorption red shift determined by optical measurements leads to a lower limit for the column density of atomic hydrogen, N(H I) not less than 4(17)/sq cm. The Lyman-alpha absorption line appears to have been detected, but only an approximate upper limit can be obtained from the data, of the order of 2(19)/sq cm. This amount of atomic hydrogen is less than that for a line of sight through the disk of a normal spiral galaxy. It is suggested that the absorbing material exists either in the halo of a galaxy or in the tenuous, extended, gaseous disk of a galaxy.

  4. The Optical Microvariability and Spectral Changes of the BL Lacertae Object S5 0716+714

    Indian Academy of Sciences (India)

    H. Poon; J. H. Fan; J. N. Fu

    2011-03-01

    The BL Lac object S5 0716+714 was monitored in the optical band during October 2008, December 2008 and February 2009. We achieved a best temporal resolution of about 5 min in the bands. The source was active during the whole monitoring campaign. It showed microvariability in 13 days out of 14 days of observation. Four fast flares were observed with amplitudes ranging from 0.3–0.75 mag. The overall amplitude changes during the whole campaign are ∼ 0. 89, ∼ 0. 80, ∼ 0. 73, and ∼ 0. 51. On internight time scales, strong bluer-when-brighter chromatism was found while different spectral behaviours were found on intranight time scales.

  5. The collective emission of electromagnetic waves from astrophysical jets - Luminosity gaps, BL Lacertae objects, and efficient energy transport

    Science.gov (United States)

    Baker, D. N.; Borovsky, Joseph E.; Benford, Gregory; Eilek, Jean A.

    1988-01-01

    A model of the inner portions of astrophysical jets is constructed in which a relativistic electron beam is injected from the central engine into the jet plasma. This beam drives electrostatic plasma wave turbulence, which leads to the collective emission of electromagnetic waves. The emitted waves are beamed in the direction of the jet axis, so that end-on viewing of the jet yields an extremely bright source (BL Lacertae object). The relativistic electron beam may also drive long-wavelength electromagnetic plasma instabilities (firehose and Kelvin-Helmholtz) that jumble the jet magnetic field lines. After a sufficient distance from the core source, these instabilities will cause the beamed emission to point in random directions and the jet emission can then be observed from any direction relative to the jet axis. This combination of effects may lead to the gap turn-on of astrophysical jets. The collective emission model leads to different estimates for energy transport and the interpretation of radio spectra than the conventional incoherent synchrotron theory.

  6. Erratic Jet Wobbling in the BL Lacertae Object OJ287 Revealed by Sixteen Years of 7mm VLBA Observations

    CERN Document Server

    Agudo, Ivan; Jorstad, Svetlana G; Gomez, Jose L; Perucho, Manel; Piner, B Glenn; Rioja, Maria; Dodson, Richard

    2011-01-01

    We present the results from an ultra-high-resolution 7mm Very Long Baseline Array (VLBA) study of the relativistic jet in the BL Lacertae object OJ287 from 1995 to 2011 containing 136 total intensity images. Analysis of the image sequence reveals a sharp jet-position-angle swing by >100 deg. during [2004,2006], as viewed in the plane of the sky, that we interpret as the crossing of the jet from one side of the line of sight to the other during a softer and longer term swing of the inner jet. Modulating such long term swing, our images also show for the first time a prominent erratic wobbling behavior of the innermost ~0.4mas of the jet with fluctuations in position angle of up to ~40 deg. over time scales ~2yr. This is accompanied by highly superluminal motions along non-radial trajectories, which reflect the remarkable non-ballistic nature of the jet plasma on these scales. The erratic nature and short time scales of the observed behavior rules out scenarios such as binary black hole systems, accretion disk ...

  7. The properties of X-ray selected and radio-selected BL Lacertae objects%X-选择和射电选择BL Lax天体的性质

    Institute of Scientific and Technical Information of China (English)

    樊军辉; 王洪光; 刘怡; 张江水; 袁聿海; 张永伟; 苏江波

    2007-01-01

    BL Lac天体表现出一系列特殊的观测性质.按照巡天方式可以分为X-选择和射电选择BL Lac天体.很多人讨论了这两者之间的关系.文章的主要工作是:①选取了两个样本;②收集了最高观测偏振读,寄主星系的绝对星等、核主导系数等;③计算了热光度、同步辐射峰频以及峰频所对应的光度、有效谱指数.基于这些数据,考察了两类BL Lac天体的性质.结果表明:X-选择和射电选择BL Lac天体在热光度、核主导系数以及有效谱指教等性质是不同的,但它们具有很相似的同步峰频光度.%BL Lacertae objects show some particularly observational properties. They were classified as radio-selected and X-ray selected BL Lacertae objects from surveys. Many authors have investigated maximum optical polarization, absolute magnitude of the host galaxy, and core-dominance parameter,cy, and the effective spectral indexes for some objects. Based on those data, we revisited the properties of BL Lacertae objects. The results show that radio-selected and X-ray selected BL Lacertae objects are different in the bolometric luminosity, the core-dominance parameters, and the effective spectral indexes, but they have similar peak-frequency luminosity.

  8. HESS J1943+213: a candidate extreme BL Lacertae object

    Science.gov (United States)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Bazer-Bachi, A. R.; Becherini, Y.; Becker, J.; Behera, B.; Bernlöhr, K.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Borrel, V.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Colom, P.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O.'C.; Dubois, F.; Dubus, G.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Goret, P.; Göring, D.; Häffner, S.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khangulyan, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Nguyen, N.; Moderski, R.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; Olive, J.-F.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Ryde, F.; Sahakian, V.; Santangelo, A.; Schlickeiser, R.; Schöck, F. M.; Schönwald, A.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Shalchi, A.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tibolla, O.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Vivier, M.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; Wierzcholska, A.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.; Burnett, T. H.; Hill, A. B.

    2011-05-01

    Context. The H.E.S.S. Cherenkov telescope array has been surveying the Galactic plane for new VHE (>100 GeV) gamma-ray sources. Aims: We report on a newly detected point-like source, HESS J1943+213. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. Methods: We combine new H.E.S.S., Fermi/LAT and Nançay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength observations of IGR J19443+2117 and discuss the likely source associations as well as the interpretation as an active galactic nucleus, a gamma-ray binary or a pulsar wind nebula. Results: HESS J1943+213 is detected at the significance level of 7.9σ (post-trials) at RA(J2000) = 19h 43m 55s ± 1^s_stat ± 1^s_sys, Dec(J2000) = +21° 18' 8'' ± 17''_stat ± 20 arcsec_sys. The source has a soft spectrum with photon index Γ = 3.1 ± 0.3stat ± 0.2sys and a flux above 470 GeV of (1.3 ± 0.2stat ± 0.3sys) × 10-12 cm-2 s-1. There is no Fermi/LAT counterpart down to a flux limit of 6 × 10-9 cm-2 s-1 in the 0.1-100 GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Γ = 2.0). The data from radio to VHE gamma-rays do not show any significant variability. Conclusions: The lack of a massive stellar counterpart disfavors the binary hypothesis, while the soft VHE spectrum would be very unusual in case of a pulsar wind nebula. In addition, the distance estimates for Galactic counterparts places them outside of the Milky Way. All available observations favor an interpretation as an extreme, high-frequency peaked BL Lac object with a redshift z > 0.14. This would be the first time a blazar is detected serendipitously from ground-based VHE observations, and the first VHE AGN detected in the Galactic Plane.

  9. ERRATIC JET WOBBLING IN THE BL LACERTAE OBJECT OJ287 REVEALED BY SIXTEEN YEARS OF 7 mm VLBA OBSERVATIONS

    Energy Technology Data Exchange (ETDEWEB)

    Agudo, Ivan; Gomez, Jose L. [Instituto de Astrofisica de Andalucia, CSIC, Apartado 3004, 18080 Granada (Spain); Marscher, Alan P.; Jorstad, Svetlana G. [Institute for Astrophysical Research, Boston University, 725 Commonwealth Avenue, Boston, MA 02215 (United States); Perucho, Manel [Departament d' Astronomia i Astrofisica, Universitat de Valencia, Dr. Moliner 50, E-46100 Burjassot, Valencia (Spain); Piner, B. Glenn [Department of Physics and Astronomy, Whittier College, 13406 East Philadelphia Street, Whittier, CA 90608 (United States); Rioja, Maria [Observatorio Astronomico Nacional, Apdo. 112, E-28803 Alcala de Henares, Madrid (Spain); Dodson, Richard, E-mail: iagudo@iaa.es [ICRAR/University of Western Australia, 35 Stirling Highway, Crawley, WA 6009 (Australia)

    2012-03-01

    We present the results from an ultra-high-resolution 7 mm Very Long Baseline Array study of the relativistic jet in the BL Lacertae object OJ287 from 1995 to 2011 containing 136 total intensity images. Analysis of the image sequence reveals a sharp jet-position-angle swing by >100 Degree-Sign during [2004,2006], as viewed in the plane of the sky, which we interpret as the crossing of the jet from one side of the line of sight to the other during a softer- and longer-term swing of the inner jet. Modulating such long-term swing, our images also show for the first time a prominent erratic wobbling behavior of the innermost {approx}0.4 mas of the jet with fluctuations in position angle of up to {approx}40 Degree-Sign over timescales {approx}2 yr. This is accompanied by highly superluminal motions along non-radial trajectories, which reflect the remarkable non-ballistic nature of the jet plasma on these scales. The erratic nature and short timescales of the observed behavior rule out scenarios such as binary black hole systems, accretion disk precession, and interaction with the ambient medium as possible origins of the phenomenon on the scales probed by our observations, although such processes may cause longer-term modulation of the jet direction. We propose that variable asymmetric injection of the jet flow, perhaps related to turbulence in the accretion disk, coupled with hydrodynamic instabilities leads to the non-ballistic dynamics that causes the observed non-periodic changes in the direction of the inner jet.

  10. Gamma-Ray and Multiwaveband Emission from Gamma-Ray-Loud BL Lacertae Objects

    Institute of Scientific and Technical Information of China (English)

    张雄; 赵刚; 郑广生; 张力

    2003-01-01

    We have collected 18 γ-ray-loud BL Lac with observed data in multiwavedand, we find that γ-ray flux densities correlate better with the near-IR flux densities than those with the optical or x-ray flux densities. There is no correlation between γ-ray and radio flux densities. Possible constraints on the γ-ray emission mechanism are discussed. We suggest that the main γ-ray radiation mechanism is probably the synchrotron self-Compton process. The inverse Compton scattering of the radiation from hot circumscribe dust, by beamed ultrarelativistic electrons, is likely to be an important complementary mechanism.

  11. Observations of BL Lacertae with MAGIC telescope

    Directory of Open Access Journals (Sweden)

    E. J. Lindfors

    2008-01-01

    Full Text Available BL Lacertae fue observado con el telescopio MAGIC de agosto a diciembre de 2005 (22.2 horas y de julio a septiembre de 2006 (26.0 horas. En 2005 se detectó, con un nivel de significación 5.1 σ, una fuerte emisión de rayos γ de muy alta energía (VHE. BL Lacertae es el primer objeto BL Lac con un pico de emisión a bajas frecuencias, en el cual se detecta este tipo de emisión. En los datos de 2006, no hay detección en la región de los rayos γ, lo que se atribuye a un menor nivel de flujo en este periodo. En este trabajo mostramos que también se observa una caida en el flujo óptico y milimétrico, lo cual sugiere una conexión entre estas tres bandas de emisión.

  12. Multifrequency observations of BL Lacertae

    Science.gov (United States)

    Bregman, Joel N.; Glassgold, A. E.; Huggins, P. J.; Neugebauer, G.; Soifer, B. T.

    1990-01-01

    Optical, IR, and radio monitoring data covering 20 years are presented for BL Lac. Also, four simultaneous multifrequency spectra are given, covering the range 10 to the 9th - 10 to the 18th Hz. These spectra include ground-based observations and data from the Einstein, Exosat, IUE, and IRAS satellites. From the monitoring data, the character of emission variability is determined using structure functions. The multifrequency spectra are used to study the origin of X-ray emission and to determine the physical parameters of emitting regions. The data show that the emitting region is inhomogeneous, with a small inner region of high density and magnetic field that eventually becomes a large, partially opaque radio emitting region with a low density and magnetic fields. Also, the two simple predictions of the synchrotron self-Compton model are reproduced by the multifrequency spectra.

  13. Optical and Radio Variability of BL Lacertae

    CERN Document Server

    Gaur, Haritma; Bachev, R; Strigachev, A; Semkov, E; Wiita, Paul J; Volvach, A E; Gu, Minfeng; Agarwal, A; Agudo, I; Aller, M F; Aller, H D; Kurtanidze, O M; Kurtanidze, S O; Lahteenmaki, A; Peneva, S; Nikolashvili, M G; Sigua, L A; Tornikoski, M; Volvach, L N

    2015-01-01

    We observed the prototype blazar, BL Lacertae, extensively in optical and radio bands during an active phase in the period 2010--2013 when the source showed several prominent outbursts. We searched for possible correlations and time lags between the optical and radio band flux variations using multifrequency data to learn about the mechanisms producing variability. During an active phase of BL Lacertae, we searched for possible correlations and time lags between multifrequency light curves of several optical and radio bands. We tried to estimate any possible variability timescales and inter-band lags in these bands. We performed optical observations in B, V, R and I bands from seven telescopes in Bulgaria, Georgia, Greece and India and obtained radio data at 36.8, 22.2, 14.5, 8 and 4.8 GHz frequencies from three telescopes in Ukraine, Finland and USA. Significant cross-correlations between optical and radio bands are found in our observations with a delay of cm-fluxes with respect to optical ones of ~250 days...

  14. An HST/COS Observation of Broad Ly$\\alpha$ Emission and Associated Absorption Lines of the BL Lacertae Object H 2356-309

    CERN Document Server

    Fang, Taotao; Buote, David A; Stocke, John T; Shull, J Michael; Canizares, Claude R; Gastaldello, Fabio

    2014-01-01

    Weak spectral features in BL Lacertae objects (BL Lac) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Ly$\\alpha$ emission line was detected. This is the fourth detection of a weak Ly$\\alpha$ emission feature in the ultraviolet (UV) band in the so-called "high energy peaked BL Lacs", after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor ($\\Gamma$) of the relativistic jet to be $\\geq 8.1$ with a maximum viewing angle of 3.6$^\\circ$. The derived $\\Gamma$ is somewhat larger than previous measurements of $\\Gamma \\approx 3 - 5$, implying a covering factor of $\\sim$ 3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be $\\sim 10^{-5}\\rm\\ M_{\\odot}$. ...

  15. BL Lacertae Objects Beyond Redshift 1.3 - UV-to-NIR Photometry and Photometric Redshift for Fermi/LAT Blazars

    Science.gov (United States)

    Rau, A.; Schady, P.; Greiner, J.; Salvato, M.; Ajello, M.; Bottacini, E.; Gehrels, N.; Afonso, P. M. J.; Elliott, J.; Filgas, R.; Kann, D. A.; Klose, S.; Kruehler, T.; Nardini, M.; Guelbenzu, A. Nicuesa; OlivaresE, F.; Rossi, A.; Sudilovsky. V.; Updike, A. C.; Hartmann, D. H.

    2011-01-01

    Context. Observations of the gamma-ray sky with Fermi led to significant advances towards understanding blazars, the most extreme class of Active Galactic Nuclei. A large fraction of the population detected by Fermi is formed by BL Lacertae (BL Lac) objects, whose sample has always suffered from a severe redshift incompleteness due to the quasi-featureless optical spectra. Aims. Our goal is to provide a significant increase of the number of confirmed high-redshift BL Lac objects contained in the 2 LAC Fermi/LAT catalog. Methods. For 103 Fermi/LAT blazars, photometric redshifts using spectral energy distribution fitting have been obtained. The photometry includes 13 broad-band filters from the far ultraviolet to the near-IR observed with Swift/UVOT and the multi-channel imager GROND at the MPG/ESO 2.2m telescope. Data have been taken quasi-simultaneously and the remaining source-intrinsic variability has been corrected for. Results. We release the UV-to-near-IR 13-band photometry for all 103 sources and provide redshift constraints for 75 sources without previously known redshift. Out of those, eight have reliable photometric redshifts at z > or approx. 1.3, while for the other 67 sources we provide upper limits. Six of the former eight are BL Lac objects, which quadruples the sample of confirmed high-redshift BL Lac. This includes three sources with redshifts higher than the previous record for BL Lac, including CRATES J0402-2615, with the best-fit solution at z approx. = 1.9.

  16. An HST/COS observation of broad Lyα emission and associated absorption lines of the BL Lacertae object H 2356-309

    Energy Technology Data Exchange (ETDEWEB)

    Fang, Taotao [Department of Astronomy and Institute of Theoretical Physics and Astrophysics, Xiamen University, Xiamen, Fujian 361005 (China); Danforth, Charles W.; Stocke, John T.; Shull, J. Michael [CASA, Department of Astrophysical and Planetary Sciences, University of Colorado, 389-UCB, Boulder, CO 80309 (United States); Buote, David A. [Department of Physics and Astronomy, 4129 Frederick Reines Hall, University of California, Irvine, CA 92697 (United States); Canizares, Claude R. [Department of Physics and Kavli Institute for Astrophysics and Space Research, Massachusetts Institute of Technology, Cambridge, MA 02139 (United States); Gastaldello, Fabio, E-mail: fangt@xmu.edu.cn [IASF-Milano, INAF, via Bassini 15, Milan I-20133 (Italy)

    2014-11-01

    Weak spectral features in BL Lacertae objects (BL Lacs) often provide a unique opportunity to probe the inner region of this rare type of active galactic nucleus. We present a Hubble Space Telescope/Cosmic Origins Spectrograph observation of the BL Lac H 2356-309. A weak Lyα emission line was detected. This is the fourth detection of a weak Lyα emission feature in the ultraviolet (UV) band in the so-called high-energy peaked BL Lacs, after Stocke et al. Assuming the line-emitting gas is located in the broad line region (BLR) and the ionizing source is the off-axis jet emission, we constrain the Lorentz factor (Γ) of the relativistic jet to be ≥8.1 with a maximum viewing angle of 3.°6. The derived Γ is somewhat larger than previous measurements of Γ ≈ 3-5, implying a covering factor of ∼3% of the line-emitting gas. Alternatively, the BLR clouds could be optically thin, in which case we constrain the BLR warm gas to be ∼10{sup –5} M {sub ☉}. We also detected two H I and one O VI absorption lines that are within |Δv| < 150 km s{sup –1} of the BL Lac object. The O VI and one of the H I absorbers likely coexist due to their nearly identical velocities. We discuss several ionization models and find a photoionization model where the ionizing photon source is the BL Lac object that can fit the observed ion column densities with reasonable physical parameters. This absorber can either be located in the interstellar medium of the host galaxy or in the BLR.

  17. Seven-Year Multi-Colour Optical Monitoring of BL Lacertae Object S5 0716+714

    Indian Academy of Sciences (India)

    Jianghua Wu; Yan Dai; Xu Zhou; Jun Ma

    2014-09-01

    We monitored the BL Lac object S5 0716+714 in five intermediate optical passbands from 2004 September to 2011 April. The object was active most of the time and intra-day variability was frequently observed. The total variation amplitude tended to decrease with decreasing frequency. Strong bluer-when-brighter chromatism was observed on both long and short timescales.

  18. Identification of gamma-ray emission from BZB J1450+5201: the most distant gamma-ray BL Lacertae object at z=2.47

    CERN Document Server

    Liao, N H; Liu, H T; Jiang, Ning; Yuan, Z L; Chen, Liang

    2013-01-01

    $\\gamma$-ray BL Lacertae objects (BL Lacs) with high redshifts ($z\\geq2$) are rarely detected. We report on an analysis of \\fermi data from five-year observation of 2FGL J1451.0+5159 whose $\\gamma$-ray emission is doubtful in the second \\fermi catalog (2FGL). It is detected at a higher energy, 3-10 GeV, with 6.7$\\sigma$ from our analysis than at 1-3 GeV from the 2FGL. The $\\gamma$-ray emission of the source is identified to be valid. Association presented in the 2FGL, between 2FGL J1451.0+5159 and BZB J1450+5201 whose redshift is suggested as 2.47, has been confirmed. BZB J1450+5201 appears to be the most distant $\\gamma$-ray BL Lac discovered to date. Multi-wavelength data from radio to $\\gamma$-ray energies are analyzed, indicating that this intermediate synchrotron peaked (ISP) source seems to be no difference from other ISP sources at lower redshifts in the second LAT AGN catalog. The pure SSC model is likely ruled out due to the extreme value of Doppler factor. Scattering of weak external emission plus S...

  19. Seven-Year Multi-Color Optical Monitoring of BL Lacertae Object S5 0716+714

    CERN Document Server

    Dai, Yan; Zhu, Zong-Hong; Zhou, Xu; Ma, Jun; Yuan, Qirong; Wang, Lingzhi

    2012-01-01

    We have monitored the BL Lac object S5 0716+714 in five intermediate optical wavebands from 2004 September to 2011 April. Here we present the data that include 8661 measurements which represents one of the largest databases obtained for an object at optical domain. A simple analysis of the data indicates that the object was active in most time, and intraday variability was frequently observed. In total, the object varied by 2.614 magnitudes in the $i$ band. Strong bluer-when-brighter chromatism was observed on long, intermediate, and short timescales.

  20. On the Location of the Gamma-ray Emission in the 2008 Outburst in the BL Lacertae Object AO 0235+164 through Observations across the Electromagnetic Spectrum

    CERN Document Server

    Agudo, Ivan; Jorstad, Svetlana G; Larionov, Valeri M; Gomez, Jose L; Lahteenmaki, Anne; Smith, Paul S; Nilsson, Kari; Readhead, Anthony C S; Aller, Margo F; Heidt, Jochen; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E; Aller, Hugh D; Benitez, Erika; Blinov, Dmitriy A; Hagen-Thorn, Vladimir A; Hiriart, David; Jannuzi, Buell T; Joshi, Manasvita; Lindfors, Elina; Molina, Sol N; Morozova, Daria A; Nieppola, Elina; Olmstead, Alice R; Reinthal, Riho; Roca--Sogorb, Mar; Schmidt, Gary D; Sillanpaa, Aimo; Takalo, Leo; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S; Zook, Alma C; Wiesemeyer, Helmut

    2011-01-01

    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array (VLBA) images at 7mm with 0.15 milliarcsecond resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte-Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight ...

  1. Optical variability of the BL Lacertae object GC 0109+224. Multiband behaviour and time scales from a 7-years monitoring campaign

    CERN Document Server

    Ciprini, S; Raiteri, C M; Villata, M; Ibrahimov, M A; Nucciarelli, G; Lanteri, L

    2003-01-01

    We present the most continuous data base of optical $BVR_{c}I_{c}$ observations ever published on the BL Lacertae object GC 0109+224, collected mainly by the robotic telescope of the Perugia University Observatory in the period November 1994-February 2002. These observations have been complemented by data from the Torino Observatory, collected in the period July 1995-January 1999, and Mt. Maidanak Observatory (December 2000). GC 0109+224 showed rapid optical variations and six major outbursts were observed at the beginning and end of 1996, in fall 1998, at the beginning and at the end of 2000, and at the beginning of 2002. Fast and large-amplitude drops characterized its flux behaviour. The $R_c$ magnitude ranged from 13.3 (16.16 mJy) to 16.46 (0.8 mJy), with a mean value of 14.9 (3.38 mJy). In the periods where we collected multi-filter observations, we analyzed colour and spectral indexes, and the variability patterns during some flares. The long-term behaviour seems approximatively achromatic, but during s...

  2. Discovery and characterization of the first low-peaked and intermediate-peaked BL Lacertae objects in the very high energy {gamma}-ray regime

    Energy Technology Data Exchange (ETDEWEB)

    Berger, Karsten

    2009-12-19

    20 years after the discovery of the Crab Nebula as a source of very high energy {gamma}-rays, the number of sources newly discovered above 100 GeV using ground-based Cherenkov telescopes has considerably grown, at the time of writing of this thesis to a total of 81. The sources are of different types, including galactic sources such as supernova remnants, pulsars, binary systems, or so-far unidentified accelerators and extragalactic sources such as blazars and radio galaxies. The goal of this thesis work was to search for {gamma}-ray emission from a particular type of blazars previously undetected at very high {gamma}-ray energies, by using the MAGIC telescope. Those blazars previously detected were all of the same type, the so-called high-peaked BL Lacertae objects. The sources emit purely non-thermal emission, and exhibit a peak in their radio-to-X-ray spectral energy distribution at X-ray energies. The entire blazar population extends from these rare, low-luminosity BL Lacertae objects with peaks at X-ray energies to the much more numerous, high-luminosity infrared-peaked radio quasars. Indeed, the low-peaked sources dominate the source counts obtained from space-borne observations at {gamma}-ray energies up to 10 GeV. Their spectra observed at lower {gamma}-ray energies show power-law extensions to higher energies, although theoretical models suggest them to turn over at energies below 100 GeV. This opened the quest for MAGIC as the Cherenkov telescope with the currently lowest energy threshold. In the framework of this thesis, the search was focused on the prominent sources BL Lac, W Comae and S5 0716+714, respectively. Two of the sources were unambiguously discovered at very high energy {gamma}-rays with the MAGIC telescope, based on the analysis of a total of about 150 hours worth of data collected between 2005 and 2008. The analysis of this very large data set required novel techniques for treating the effects of twilight conditions on the data quality

  3. Discovery of hard-spectrum γ-ray emission from the BL Lacertae object 1ES 0414+009

    Science.gov (United States)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Barres de Almeida, U.; Becherini, Y.; Becker, J.; Behera, B.; Bernloehr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Buesching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Chounet, L.-M.; Clapson, A. C.; Coignet, G.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataie, A.; Domainko, W.; Drury, L. O'c.; Dubois, F.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Farnier, C.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Foerster, A.; Fuesling, M.; Gallant, Y. A.; Gast, H.; Gerard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glueck, B.; Goret, P.; Goering, D.; Haeffner, S.; Hague, J. D.; Hampf, D.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hinton, J. A.; Hoffmann, A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzynski, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khangulyan, D.; Khelifi, B.; Klochkov, D.; Kluzniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Laffon, H.; Lamanna, G.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maurin, D.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Mehault, J.; Moderski, R.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Ona Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pedaletti, G.; Pelletier, G.; Petrucci, P.-O.; Pita, S.; Puehlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de Los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Ruppel, J.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schoeck, F. M.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Sikora, M.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, L.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Vialle, J. P.; Viana, A.; Vincent, P.; Voelk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S. L.; Costamante, L.; Fegan, S.; Ajello, M.

    2012-02-01

    Context. 1ES 0414 + 009 (z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high-energy (VHE, E > 100 GeV) γ-rays due to its high X-ray and radio flux. Aims: Observations in the VHE γ-ray band and across the electromagnetic spectrum can provide insights into the origin of highly energetic particles present in the source and the radiation processes at work. Because of the distance of the source, the γ-ray spectrum might provide further limits on the level of the extragalactic background light (EBL). Methods: We report observations made between October 2005 and December 2009 with H.E.S.S., an array of four imaging atmospheric Cherenkov telescopes. Observations at high energies (HE, 100 MeV-100 GeV) with the Fermi-LAT instrument in the first 20 months of its operation are also reported. To complete the multi-wavelength picture, archival UV and X-ray observations with the Swift satellite and optical observations with the ATOM telescope are also used. Results: Based on the observations with H.E.S.S., 1ES 0414 + 009 is detected for the first time in the VHE band. An excess of 224 events is measured, corresponding to a significance of 7.8σ. The photon spectrum of the source is well described by a power law, with photon index of ΓVHE = 3.45 ± 0.25stat ± 0.20syst. The integral flux above 200 GeV is (1.88 ± 0.20stat ± 0.38syst) × 10-12 cm-2 s-1. Observations with the Fermi-LAT in the first 20 months of operation show a flux between 200 MeV and 100 GeV of (2.3 ± 0.2stat) × 10-9 erg cm-2 s-1, and a spectrum well described by a power-law function with a photon index ΓHE = 1.85 ± 0.18. Swift/XRT observations show an X-ray flux between 2 and 10 keV of (0.8-1) × 10-11 erg cm-2 s-1, and a steep spectrum ΓX = (2.2-2.3). Combining X-ray with optical-UV data, a fit with a log-parabolic function locates the synchrotron peak around 0.1 keV. Conclusions: Although the GeV-TeV observations do not provide better

  4. On the Location of the gamma-Ray Outburst Emission in the BL Lacertae Object AO 0235 + 164 Through Observations Across the Electromagnetic Spectrum

    Science.gov (United States)

    Agudo, Ivan; Marscher, Alan P.; Jorstad, Svetlana G.; Larionov, Valeri M.; Gomez, Jose L.; Laehteenmaeki, Anne; Smith, Paul S.; Nilsson, Kari; Readhead, Anthony C. S.; Aller, Margo F.; Heidt, Jochien; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E.; Nikolashvili, Maria G.; Aller, Hugh D.; Benitez, Erika; Blinov, Dmitriy A.; Hagen-Thorn, Vladimir A.; Hiriart, David; Jannuzi, Buell T.; Joshi, Manasvita; Kimeridze, Givi N.; Kurtanidze, Omar M.; Kurtanidze, Sofia O.

    2011-01-01

    We present observations of a major outburst at centimeter, millimeter, optical, X-ray, and gamma-ray wavelengths of the BL Lacertae object AO 0235+164. We analyze the timing of multi-waveband variations in the flux and linear polarization, as well as changes in Very Long Baseline Array images at A = 7 mm with approx.0.15 milliarcsec resolution. The association of the events at different wavebands is confirmed at high statistical significance by probability arguments and Monte Carlo simulations. A series of sharp peaks in optical linear polarization, as well as a pronounced maximum in the 7 mm polarization of a superluminal jet knot, indicate rapid fluctuations in the degree of ordering of the magnetic field. These results lead us to conclude that the outburst occurred in the jet both in the quasi-stationary "core" and in the superluminal knot, both parsecs downstream of the supermassive black hole. We interpret the outburst as a consequence of the propagation of a disturbance, elongated along the line of sight by light-travel time delays, that passes through a standing recollimation shock in the core and propagates down the jet to create the superluminal knot. The multi-wavelength light curves vary together on long timescales (months/ years), but the correspondence is poorer on shorter timescales. This, as well as the variability of the polarization and the dual location of the outburst, agrees with the expectations of a multi-zone emission model in which turbulence plays a major role in modulating the synchrotron and inverse Compton fluxes.

  5. KEPLER OBSERVATIONS OF RAPID OPTICAL VARIABILITY IN THE BL LACERTAE OBJECT W2R1926+42

    Energy Technology Data Exchange (ETDEWEB)

    Edelson, R.; Mushotzky, R. [Department of Astronomy, University of Maryland, College Park, MD 20742-2421 (United States); Vaughan, S. [X-ray and Observational Astronomy Group, Department of Physics and Astronomy, University of Leicester, University Road, Leicester LE1 7RH (United Kingdom); Scargle, J. [Astrobiology and Space Science Division, NASA Ames Research Center, Moffet Field, CA 94035 (United States); Gandhi, P. [Institute of Space and Astronautical Science, Japan Aerospace Exploration Agency, 3-1-1 Yoshinodai, chuo-ku, Sagamihara, Kanagawa 252-5210 (Japan); Malkan, M. [Department of Physics and Astronomy, University of California Los Angeles, Los Angeles, CA 90095-1547 (United States); Baumgartner, W., E-mail: redelson@astro.umd.edu [Laboratory for High Energy Astrophysics, NASA/GSFC, Code 662, Greenbelt, MD 20771 (United States)

    2013-03-20

    We present the first Kepler monitoring of a strongly variable BL Lac, W2R1926+42. The light curve covers 181 days with {approx}0.2% errors, 30 minute sampling and >90% duty cycle, showing numerous {delta}I/I > 25% flares over timescales as short as a day. The flux distribution is highly skewed and non-Gaussian. The variability shows a strong rms-flux correlation with the clearest evidence to date for nonlinearity in this relation. We introduce a method to measure periodograms from the discrete autocorrelation function, an approach that may be well-suited to a wide range of Kepler data. The periodogram is not consistent with a simple power-law, but shows a flattening at frequencies below 7 Multiplication-Sign 10{sup -5} Hz. Simple models of the power spectrum, such as a broken power law, do not produce acceptable fits, indicating that the Kepler blazar light curve requires more sophisticated mathematical and physical descriptions than currently in use.

  6. Broadband Spectra and Variability of BL Lacertae in 2000

    CERN Document Server

    Böttcher, M; Aller, M F; Mang, O; Raiteri, C M; Ravasio, M; Tagliaferri, G; Teraesranta, H; Villata, M

    2002-01-01

    We have organized an extensive multiwavelength campaign on BL Lacertae in the second half of 2000. Simultaneous or quasi-simultaneous observations were taken at radio frequencies, in the optical - carried out by the WEBT collaboration -, in X-rays - using BeppoSAX and RXTE -, and at VHE gamma-rays with the CAT and HEGRA Cherenkov telescope facilities. In this paper, we are presenting first results from this campaign. The WEBT optical campaign achieved an unprecedented time coverage, virtually continuous over several 10 - 20 hour segments, and revealed intraday variability on time scales of ~ 1.5 hours. The X-ray observations of Nov. 1 - 2, 2000, revealed significant variability on similar time scales, and provided evidence for the synchrotron spectrum extending out to ~ 10 keV during that time. At higher energies, the onset of the hard power-law commonly observed in radio-loud quasars and radio-selected BL Lac objects is seen. From the energy-resolved X-ray variability patterns, we find evidence that electron...

  7. Location of gamma-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 more than 14pc from the Central Engine

    CERN Document Server

    Agudo, Ivan; Marscher, Alan P; Larionov, Valeri M; Gomez, Jose L; Lahteenmaki, Anne; Gurwell, Mark A; Smith, Paul S; Wiesemeyer, Helmut; Thum, Clemens; Heidt, Jochen; Blinov, Dmitriy A; D'Arcangelo, Francesca D; Hagen-Thorn, Vladimir A; Morozova, Daria A; Nieppola, Elina; Roca-Sogorb, Mar; Schmidt, Gary D; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S

    2010-01-01

    We combine time-dependent multi-waveband flux and linear polarization observations with sub-milliarcsecond-scale polarimetric images at lambda=7mm of the BL Lacertae-type blazar OJ287 to locate the gamma-ray emission in prominent flares in the jet of the source >14pc from the central engine. We demonstrate a highly significant correlation between the strongest gamma-ray and millimeter-wave flares through Monte-Carlo simulations. The two reported gamma-ray peaks occurred near the beginning of two major mm-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our Very Long Baseline Array observations indicate that the two mm-wave flares originated in the second of two features in the jet that are separated by >14 pc. The simultaneity of the peak of the higher-amplitude gamma-ray flare and the maximum in polarization of the second jet feature implies that the gamma-ray and mm-wave flares are co-spatial and occur >14 pc from the central engine. We also associate...

  8. Location of γ-ray Flare Emission in the Jet of the BL Lacertae Object OJ287 More than 14 pc from the Central Engine

    Science.gov (United States)

    Agudo, Iván; Jorstad, Svetlana G.; Marscher, Alan P.; Larionov, Valeri M.; Gómez, José L.; Lähteenmäki, Anne; Gurwell, Mark; Smith, Paul S.; Wiesemeyer, Helmut; Thum, Clemens; Heidt, Jochen; Blinov, Dmitriy A.; D'Arcangelo, Francesca D.; Hagen-Thorn, Vladimir A.; Morozova, Daria A.; Nieppola, Elina; Roca-Sogorb, Mar; Schmidt, Gary D.; Taylor, Brian; Tornikoski, Merja; Troitsky, Ivan S.

    2011-01-01

    We combine time-dependent multi-waveband flux and linear polarization observations with submilliarcsecond-scale polarimetric images at λ = 7 mm of the BL Lacertae type blazar OJ287 to locate the γ-ray emission in prominent flares in the jet of the source >14 pc from the central engine. We demonstrate a highly significant correlation between the strongest γ-ray and millimeter-wave flares through Monte Carlo simulations. The two reported γ-ray peaks occurred near the beginning of two major millimeter-wave outbursts, each of which is associated with a linear polarization maximum at millimeter wavelengths. Our very long baseline array observations indicate that the two millimeter-wave flares originated in the second of two features in the jet that are separated by >14 pc. The simultaneity of the peak of the higher-amplitude γ-ray flare and the maximum in polarization of the second jet feature implies that the γ-ray and millimeter-wave flares are cospatial and occur >14 pc from the central engine. We also associate two optical flares, accompanied by sharp polarization peaks, with the two γ-ray events. The multi-waveband behavior is most easily explained if the γ-rays arise from synchrotron self-Compton scattering of optical photons from the flares. We propose that flares are triggered by interaction of moving plasma blobs with a standing shock. The γ-ray and optical emission is quenched by inverse Compton losses as synchrotron photons from the newly shocked plasma cross the emission region. The millimeter-wave polarization is high at the onset of a flare, but decreases as the electrons emitting at these wavelengths penetrate less polarized regions.

  9. Analyses of the Light Variations of OJ 287, 0716+714 and BL Lacertae

    Science.gov (United States)

    Wang, Hong-tao; Pan, Yan-ping

    2013-01-01

    OJ 287 is a BL Lac object which exhibits intense activities of low peak-frequencies. Its energy spectrum in low frequency band is quite similar with those of two other TeV BL Lac objects (i.e., 0716+714 and BL Lacertae). However, the Cerenkov telescope did not detect its TeV rays. By using the observational data of these three heavenly bodies and comparing the discrepan- cies of their minimal periods of light variations and delays at 22 GHz, 37 GHz and B-waveband, we have further investigated the possible reason why the TeV gamma-rays of OJ 287 have not been observed. The results of analyses are as fol- lows. (1) For the minimal periods of light variations, the periods of OJ 287 at 37 GHZ and B-waveband are short. At 22 GHz the results of OJ 287 and 0716+714 are comparable, but the period of OJ 287 is much shorter in comparison with that of BL Lacertae, and this shows that its activity is more intense. However, the TeV gamma-rays of OJ 287 have not been detected, which implies that the radiation of OJ 287 in TeV waveband may have no connection with the minimal periods of light variations in these three low-energy wavebands. (2) In respect of delays, the delay of OJ 287 in the B waveband with respect to 37 GHz is longer than that of 0716+714, but shorter than that of BL Lacertae. Its delay at 37 GHz in respect to 22 GHz is shorter than that of 0716+714. Meanwhile, the delay of BL Lacertae at 37 GHz in respect to 22 GHz is negative, which implies that 22 GHz precedes 37 GHz. Via the comparison and analysis of delays, no obvious differences between OJ 287 and 0716+714 as well as BL Lacertae have been found. On the side of energy spectra, it is quite possible that due to the steep energy spectrum of OJ 287 in TeV waveband, the Cerenkov telescope has not detected the gamma radiation of OJ 287. However, nowadays it is still not clear whether the steep energy spectrum in TeV energy range has some influence on the light variations in low energy realm.

  10. A synchrotron self-Compton scenario for the very high energyγ-ray emission of the intermediate BL Lacertae object W Comae

    Institute of Scientific and Technical Information of China (English)

    Jin Zhang

    2009-01-01

    W Comae has significant variability in multi-wavelengthes, from radio to gamma-ray bands. A bright outburst in optical and X-ray bands was observed in 1998, and most recently, a strong TeV flare was detected by VERITAS in 2008. It is the first TeV intermediate-frequency-peaked BL Lacertae source. I find that both the broadband spectral energy distributions (SEDs) which were quasi-simultaneously obtained during the TeV flare and during the optical/X-ray outburst are well fit by using a single-zone synchrotron + synchrotron-self-Compton model. The satisfactory fitting requires a large beaming factor, i.e., δ~25 and δ~20 for the TeV flare and the optical/X-ray outburst, respectively, suggesting that both the optical/X-ray outburst and the TeV flare are from a relativistic jet. The size of the emission region of the TeV flare is three times larger than that of the optical/X-ray outburst, and the strength of the magnetic field for the TeV flare is~14 times smaller than that of the X-ray/optical outburst, likely indicating that the region of the TeV flare is more distant from the core than that of the X-ray/optical outburst. The inverse Compton component of the TeV flare peaks around 1.3 GeV, but it is around 0 MeV for the X-ray/optical outburst, lower than that for the TeV flare by two orders of magnitude. The model predicts that the optical/X-ray outburst might be accompanied by a strong MeV/GeV emission, but the TeV flare may be not associated with the X-ray/optical outburst. The GeV emission is critical for characterizing the SEDs of the optical/X-ray outburst and the TeV flare. The predicted GeV flux is above the sensitivity of Fermi/LAT, and it could be verified with the observations by Fermi/LAT in the near future.

  11. Parsec-scale jet precession in BL Lacertae (2200+420)

    OpenAIRE

    Caproni, Anderson; Abraham, Zulema; Monteiro, Hektor

    2012-01-01

    BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic ...

  12. X-Ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lacertae Objects

    Science.gov (United States)

    Krawczynski, H.

    2007-04-01

    In this paper we discuss models of the X-ray and TeV γ-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole, due to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constraints on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole (~100-1000 G). However, the model fits imply that the magnetic field in the emission region is only ~0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to ~20 TeV energies. Although the parallel beam model has its own problems, it explains some of the long-standing problems that plague models based on Fermi-type particle acceleration, such as the presence of a very high minimum Lorentz factor of accelerated particles. We conclude with a brief discussion of the implications of the model for the difference between the processes of jet formation in BL Lac-type objects and those in quasars.

  13. The WEBT BL Lacertae Campaign 2001 and its extension

    CERN Document Server

    Villata, M; Kurtanidze, O M; Nikolashvili, M G; Ibrahimov, M A; Papadakis, I E; Tosti, G; Hroch, F; Takalo, L O; Sillanpää, A; Hagen-Thorn, V A; Larionov, V M; Schwartz, R D; Basler, J; Brown, L F; Balonek, T J; Benítez, E; Ramírez, A; Sadun, A C; Boltwood, P; Carini, M T; Barnaby, D; Coloma, J M; Ros, J A; Dai, B Z; Xie, G Z; Mattox, J R; Rodríguez, D; Asfandiyarov, I M; Atkerson, A; Beem, J L; Bloom, S D; Chanturiya, S M; Ciprini, S; Crapanzano, S; De Diego, J A; Efimova, N V; Gardiol, D; Guerra, J C; Kahharov, B B; Kapanadze, B Z; Karttunen, H; Kato, T; Kimeridze, G N; Kudryavtseva, N A; Lainela, M; Lanteri, L; Larionova, E G; Maesano, M; Marchili, N; Massone, G; Monroe, T; Montagni, F; Nesci, R; Nilsson, K; Noble, J C; Nucciarelli, G; Ostorero, L; Papamastorakis, J; Pasanen, M; Peters, C S; Pursimo, T; Reig, P; Ryle, W; Sclavi, S; Sigua, L A; Uemura, M; Wills, W

    2004-01-01

    BL Lacertae has been the target of four observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration. In this paper we present $UBVRI$ light curves obtained by the WEBT from 1994 to 2002, including the last, extended BL Lac 2001 campaign. A total of about 7500 optical observations performed by 31 telescopes from Japan to Mexico have been collected, to be added to the $\\sim 15600$ observations of the BL Lac Campaign 2000. All these data allow one to follow the source optical emission behaviour with unprecedented detail. The analysis of the colour indices reveals that the flux variability can be interpreted in terms of two components: longer-term variations occurring on a few-day time scale appear as mildly-chromatic events, while a strong bluer-when-brighter chromatism characterizes very fast (intraday) flares. By decoupling the two components, we quantify the degree of chromatism inferring that longer-term flux changes imply moving along a $\\sim 0.1$ bluer-when-brighter slope in the $B-R$ vers...

  14. SIMULTANEOUS B'V'R' MONITORING OF BL LACERTAE OBJECT S5 0716+714 AND DETECTION OF INTER-BAND TIME DELAY

    Energy Technology Data Exchange (ETDEWEB)

    Wu Jianghua; He Xiangtao [Department of Astronomy, Beijing Normal University, Beijing 100875 (China); Boettcher, Markus [Astrophysical Institute, Department of Physics and Astronomy, Ohio University, Athens, OH 45701 (United States); Zhou Xu; Ma Jun; Jiang Zhaoji, E-mail: jhwu@bnu.edu.cn [Key Laboratory of Optical Astronomy, National Astronomical Observatories, Chinese Academy of Sciences, 20A Datun Road, Chaoyang District, Beijing 100012 (China)

    2012-05-15

    We present the results of our optical monitoring of the BL Lac object S5 0716+714 over seven nights in 2006 December. The monitoring was carried out simultaneously at three optical wavelengths with a novel photometric system. The object did not show large-amplitude internight variations during this period. Intranight variations were observed on four nights and probably on one more. Strong bluer-when-brighter chromatism was detected on both intranight and internight timescales. The intranight variation amplitude decreases in the wavelength sequence of B', R', and V'. Cross-correlation analyses revealed that the variability at the B' and V' bands leads that at the R' band by about 30 minutes on one night.

  15. Another look at the BL Lacertae flux and spectral variability

    CERN Document Server

    Raiteri, C M; Bruschini, L; Capetti, A; Kurtanidze, O M; Larionov, V M; Romano, P; Vercellone, S; Agudo, I; Aller, H D; Aller, M F; Arkharov, A A; Bach, U; Berdyugin, A; Blinov, D A; Böttcher, M; Buemi, C S; Calcidese, P; Carosati, D; Casas, R; Chen, W -P; Coloma, J; Diltz, C; Di Paola, A; Dolci, M; Efimova, N V; Forné, E; Gómez, J L; Gurwell, M A; Hakola, A; Hovatta, T; Hsiao, H Y; Jordan, B; Jorstad, S G; Koptelova, E; Kurtanidze, S O; Lähteenmäki, A; Larionova, E G; Leto, P; Lindfors, E; Ligustri, R; Marscher, A P; Morozova, D A; Nikolashvili, M G; Nilsson, K; Ros, J A; Roustazadeh, P; Sadun, A C; Sillanpää, A; Sainio, J; Takalo, L O; Tornikoski, M; Trigilio, C; Troitsky, I S; Umana, G

    2010-01-01

    The GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) monitored BL Lacertae in 2008-2009 at radio, near-IR, and optical frequencies. During this period, high-energy observations were performed by XMM-Newton, Swift, and Fermi. We analyse these data with particular attention to the calibration of Swift UV data, and apply a helical jet model to interpret the source broad-band variability. The GASP-WEBT observations show an optical flare in 2008 February-March, and oscillations of several tenths of mag on a few-day time scale afterwards. The radio flux is only mildly variable. The UV data from both XMM-Newton and Swift seem to confirm a UV excess that is likely caused by thermal emission from the accretion disc. The X-ray data from XMM-Newton indicate a strongly concave spectrum, as well as moderate flux variability on an hour time scale. The Swift X-ray data reveal fast (interday) flux changes, not correlated with those observed at lower energies. We compare the spectral energy distri...

  16. The jet of the BL Lacertae object PKS 2201+044: MAD near-IR adaptive optics observations and comparison with optical, radio and X-ray data

    Science.gov (United States)

    Liuzzo, E.; Falomo, R.; Treves, A.; Donato, D.; Sambruna, M.; Arcidiacono, C.; Giovannini, G.; Farinato, J.; Moretti, A.; Ragazzoni, R.; Diolaiti, E.; Lombini, M.; Brast, R.; Donaldson, R.; Kolb, J.; Marchetti, E.; Tordo, S.

    2011-04-01

    Context. Relativistic jets are a common feature of radio loud active galactic nuclei. Multifrequency observations are a unique tool to constrain their physics. Aims: We report on a detailed study of the properties of the jet of the nearby BL Lac object PKS 2201+044, one of the rare cases where the jet is detected from radio to X-rays. Methods: We use new adaptive optics near-IR observations of the source, obtained with the ESO multi-conjugated adaptive optics demonstrator (MAD) at the Very Large Telescope. These observations acquired in Ground-Layer Adaptive Optics mode are combined with images previously achieved by HST, VLA and Chandra to perform a morphological and photometric study of the jet. Results: We find a noticeable similarity in the morphology of the jet at radio, near-IR and optical wavelengths. We construct the spectral shape of the main knot of jet that appears dominated by synchrotron radiation. Conclusions: On the basis of the jet morphology and the weak lines spectrum we suggest that PKS 2201+044 belongs to the class of radio sources intermediate between FRIs and FRIIs.

  17. Discovery of VHE γ-ray emission and multi-wavelength observations of the BL Lacertae object 1RXS J101015.9-311909

    Science.gov (United States)

    H.E.S.S. Collaboration; Abramowski, A.; Acero, F.; Aharonian, F.; Akhperjanian, A. G.; Anton, G.; Balzer, A.; Barnacka, A.; Becherini, Y.; Becker, J.; Bernlöhr, K.; Birsin, E.; Biteau, J.; Bochow, A.; Boisson, C.; Bolmont, J.; Bordas, P.; Brucker, J.; Brun, F.; Brun, P.; Bulik, T.; Büsching, I.; Carrigan, S.; Casanova, S.; Cerruti, M.; Chadwick, P. M.; Charbonnier, A.; Chaves, R. C. G.; Cheesebrough, A.; Cologna, G.; Conrad, J.; Dalton, M.; Daniel, M. K.; Davids, I. D.; Degrange, B.; Deil, C.; Dickinson, H. J.; Djannati-Ataï, A.; Domainko, W.; Drury, L. O'C.; Dubus, G.; Dutson, K.; Dyks, J.; Dyrda, M.; Egberts, K.; Eger, P.; Espigat, P.; Fallon, L.; Fegan, S.; Feinstein, F.; Fernandes, M. V.; Fiasson, A.; Fontaine, G.; Förster, A.; Füßling, M.; Gallant, Y. A.; Gast, H.; Gérard, L.; Gerbig, D.; Giebels, B.; Glicenstein, J. F.; Glück, B.; Göring, D.; Häffner, S.; Hague, J. D.; Hahn, J.; Hampf, D.; Harris, J.; Hauser, M.; Heinz, S.; Heinzelmann, G.; Henri, G.; Hermann, G.; Hillert, A.; Hinton, J. A.; Hofmann, W.; Hofverberg, P.; Holler, M.; Horns, D.; Jacholkowska, A.; de Jager, O. C.; Jahn, C.; Jamrozy, M.; Jung, I.; Kastendieck, M. A.; Katarzyński, K.; Katz, U.; Kaufmann, S.; Keogh, D.; Khélifi, B.; Klochkov, D.; Kluźniak, W.; Kneiske, T.; Komin, Nu.; Kosack, K.; Kossakowski, R.; Krayzel, F.; Laffon, H.; Lamanna, G.; Lenain, J.-P.; Lennarz, D.; Lohse, T.; Lopatin, A.; Lu, C.-C.; Marandon, V.; Marcowith, A.; Masbou, J.; Maxted, N.; Mayer, M.; McComb, T. J. L.; Medina, M. C.; Méhault, J.; Moderski, R.; Mohamed, M.; Moulin, E.; Naumann, C. L.; Naumann-Godo, M.; de Naurois, M.; Nedbal, D.; Nekrassov, D.; Nguyen, N.; Nicholas, B.; Niemiec, J.; Nolan, S. J.; Ohm, S.; de Oña Wilhelmi, E.; Opitz, B.; Ostrowski, M.; Oya, I.; Panter, M.; Paz Arribas, M.; Pekeur, N. W.; Pelletier, G.; Perez, J.; Petrucci, P.-O.; Peyaud, B.; Pita, S.; Pühlhofer, G.; Punch, M.; Quirrenbach, A.; Raue, M.; Rayner, S. M.; Reimer, A.; Reimer, O.; Renaud, M.; de los Reyes, R.; Rieger, F.; Ripken, J.; Rob, L.; Rosier-Lees, S.; Rowell, G.; Rudak, B.; Rulten, C. B.; Sahakian, V.; Sanchez, D. A.; Santangelo, A.; Schlickeiser, R.; Schulz, A.; Schwanke, U.; Schwarzburg, S.; Schwemmer, S.; Sheidaei, F.; Skilton, J. L.; Sol, H.; Spengler, G.; Stawarz, Ł.; Steenkamp, R.; Stegmann, C.; Stinzing, F.; Stycz, K.; Sushch, I.; Szostek, A.; Tavernet, J.-P.; Terrier, R.; Tluczykont, M.; Valerius, K.; van Eldik, C.; Vasileiadis, G.; Venter, C.; Viana, A.; Vincent, P.; Völk, H. J.; Volpe, F.; Vorobiov, S.; Vorster, M.; Wagner, S. J.; Ward, M.; White, R.; Wierzcholska, A.; Zacharias, M.; Zajczyk, A.; Zdziarski, A. A.; Zech, A.; Zechlin, H.-S.

    2012-06-01

    1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus (called AGN) belonging to the class of bright BL Lac objects. Observations at high (HE, E > 100 MeV) and very high (VHE, E > 100 GeV) energies provide insights into the origin of very energetic particles present in such sources and the radiation processes at work. We report on results from VHE observations performed between 2006 and 2010 with the H.E.S.S. instrument, an array of four imaging atmospheric Cherenkov telescopes. H.E.S.S. data have been analysed with enhanced analysis methods, making the detection of faint sources more significant. VHE emission at a position coincident with 1RXS J101015.9-311909 is detected with H.E.S.S. for the first time. In a total good-quality livetime of about 49 h, we measure 263 excess counts, corresponding to a significance of 7.1 standard deviations. The photon spectrum above 0.2 TeV can be described by a power-law with a photon index of Γ = 3.08 ± 0.42stat ± 0.20sys. The integral flux above 0.2 TeV is about 0.8% of the flux of the Crab nebula and shows no significant variability over the time reported. In addition, public Fermi/LAT data are analysed to search for high energy emission from the source. The Fermi/LAT HE emission in the 100 MeV to 200 GeV energy range is significant at 8.3 standard deviations in the chosen 25-month dataset. UV and X-ray contemporaneous observations with the Swift satellite in May 2007 are also reported, together with optical observations performed with the atom telescope located at the H.E.S.S. site. Swift observations reveal an absorbed X-ray flux of F(0.3-7) keV = 1.04+0.04-0.05 × 10-11 erg cm-2 s-1 in the 0.3-7 keV range. Finally, all the available data are used to study the multi-wavelength properties of the source. The spectral energy distribution (SED) can be reproduced using a simple one-zone Synchrotron Self Compton (SSC) model with emission from a region with a Doppler factor of 30 and a

  18. Non-radial motion in the TeV blazar S5 0716+714. The pc-scale kinematics of a BL Lacertae object

    Science.gov (United States)

    Britzen, S.; Kam, V. A.; Witzel, A.; Agudo, I.; Aller, M. F.; Aller, H. D.; Karouzos, M.; Eckart, A.; Zensus, J. A.

    2009-12-01

    Context: Flat-spectrum radio sources often show a core-jet structure on pc-scales. Individual jet components reveal predominantly outward directed motion. For the BL Lac object S5 0716+714 conflicting apparent velocities have been reported in the literature. This object is an intra-day variable source and suited to investigate a possible correlation between kinematic properties and flux-density variability on different timescales. Aims: We study the kinematics in the pc-scale jet of S5 0716+714 to determine the apparent speeds of the jet components based on a much improved data set. In addition, we search for correlations between the radio flux-density light curves and the morphological changes detected along the VLBI jet. Methods: We (re-)analyze 50 VLBI observations obtained with the VLBA at 5 different frequencies (5-43 GHz) between 1992.73 and 2006.32. The data have been parameterized using circular Gaussian components. We analyze the jet component motion in detail taking care not only to account for motion in the radial but also in the orthogonal direction. We study the evolution of the jet ridge line and investigate the spectral properties of the individual components. We search for correlations between radio band light curves and the kinematic properties of the jet components. Results: We present an alternative kinematic scenario for jet component motion in S5 0716+714. We present evidence for the apparent stationarity of jet components (with regard to their core separation) with time. Jet components, however, do seem to move significantly non-radially with regard to their position angle and in a direction perpendicular to the major axis of the jet. We discuss a possible correlation between the long-term radio flux-density variability and apparent jet component motions. Conclusions: In S5 0716+714 an alternative motion scenario is proposed. With regard to the core separation, rather stationary components can fit the VLBI observations well. A new model to

  19. Parsec-scale jet precession in BL Lacertae (2200+420)

    Science.gov (United States)

    Caproni, A.; Abraham, Z.; Monteiro, H.

    2013-01-01

    BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic jet-precession model. The seven free parameters of our precession model were optimized via a heuristic cross-entropy method, comparing the projected precession helix with the positions of the jet components on the plane of the sky and imposing constraints on their maximum and minimum superluminal velocities. Our optimized best model is compatible with a jet having a bulk velocity of 0.9824c, which is precessing with a period of about 12.1 yr in the observer's reference frame and changing its orientation in relation to the line of sight between 4° and 5°, approximately. Assuming that the jet precession has its origin in a supermassive binary black hole system, we show that the 2.3-yr periodic variation in the structural position angle of the very-long-baseline interferometry (VLBI) core of BL Lacertae reported by Stirling et al. is compatible with a nutation phenomenon if the secondary black hole has a mass higher than about six times that of the primary black hole.

  20. Estudio de variabilidad del blazar BL Lacertae: desde radio hasta rayos gamma (2008-2015)

    Science.gov (United States)

    Pichel, A.; Rovero, A. C.

    2016-08-01

    The aim of this work is to study the blazar BL Lacertae during extended periods (greater than weeks), by characterizing the changes in flux and polarization at optical, radio, X-rays and gamma rays; also to investigate the possible correlations between different bands. We look for periodicity in the flux variations in different bands, looking for criteria to predict high activity states of the source. We use multi-frequency observations of BL Lacertae obtained during the years 2008--2015, from radio to very-high-energy gamma rays. During this period, the source remained mainly in a low state of activity at the high energy bands, with several episodes of high activity (flares) in different bands, some of them observed simultaneously in several bands.

  1. Analysis of the activity of the blazar BL Lacertae over the period 1998-2011

    Science.gov (United States)

    Strigunov, K. S.; Zhovtan, A. V.

    2016-07-01

    In 1998-2011 the blazar (active galactic nucleus) BL Lacertae was observed at Crimean Astrophysical Observatory (CrAO) with the second-generation GT-48 Cherenkov telescope at energies >1 TeV with a total significance of 11.8σ. More than 20 flares and a fourfold change in yearly mean fluxes (>1 TeV) were recorded. The optical ( B band) data obtained at CrAO and the TeV data are shown to correlate in some time intervals. The optical data are also compared with the X-ray RXTE/ASM (2-10 keV) data. In addition, the data from GT-48 are compared with the gamma-ray fluxes recorded by the Fermi LAT space telescope (0.1-300 GeV). The 2009 flare at TeV and Fermi energies has been studied. As a result, it has been found that as the activity rises the increase in flux at high energies exceeds its increase at low energies. This conclusion may be related to the conversion mechanism of particle acceleration. This is consistent with the results of studies for a similar object, 1ES 1426+428.

  2. Parsec-scale jet precession in BL Lacertae (2200+420)

    CERN Document Server

    Caproni, Anderson; Monteiro, Hektor

    2012-01-01

    BL Lacertae is the prototype of the BL Lac class of active galactic nuclei, exhibiting intensive activity on parsec (pc) scales, such as intense core variability and multiple ejections of jet components. In particular, in previous works the existence of precession motions in the pc-scale jet of BL Lacertae has been suggested. In this work we revisit this issue, investigating temporal changes of the observed right ascension and declination offsets of the jet knots in terms of our relativistic jet-precession model. The seven free parameters of our precession model were optimized via a heuristic cross-entropy method, comparing the projected precession helix with the positions of the jet components on the plane of the sky and imposing constraints on their maximum and minimum superluminal velocities. Our optimized best model is compatible with a jet having a bulk velocity of 0.9824c, which is precessing with a period of about 12.1 yr in the observer's reference frame and changing its orientation in relation to the...

  3. Synchrotron and Compton Components and their Variability in BL Lac Objects

    CERN Document Server

    Giommi, P; Padovani, P; Tagliaferri, G

    2000-01-01

    BL Lacertae objects are extreme extragalactic sources characterized by theemission of strong and rapidly variable nonthermal radiation over the entireelectromagnetic spectrum. Synchrotron emission followed by inverse Comptonscattering in a relativistic beaming scenario is generally thought to be themechanism powering these objects. ...

  4. Broad-Band Spectral Indices Variability of BL Lacertae by Wavelet Method

    Indian Academy of Sciences (India)

    Hao-Jing Zhang; Jing-Ming Bai; Yu-Ying Bao; Xiong Zhang

    2014-09-01

    BL Lacertae is one of the famous AGN that shows convincing evidence to support periodic variability. We compile R-band data and radio 22 GHz database from the available literature to build the light curves and to calculate broad-band spectral indices. This paper employs the wavelet periodic estimation method. The analysis results indicate that the most possible period is 7.02–7.36 yr in the selected wave-bands. The broad-band spectral indices have a possible period of 4.11 yr as a half value in selected wave-bands. The results confirm that the variability period in the radio 22 GHz is in agreement with the optical R band of about 7.01 yr, as also mentioned in other literatures.

  5. RAPID TeV GAMMA-RAY FLARING OF BL LACERTAE

    Energy Technology Data Exchange (ETDEWEB)

    Arlen, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Aune, T.; Bouvier, A. [Santa Cruz Institute for Particle Physics and Department of Physics, University of California, Santa Cruz, CA 95064 (United States); Beilicke, M.; Buckley, J. H.; Bugaev, V.; Dickherber, R. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Benbow, W. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Cesarini, A.; Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Cui, W.; Feng, Q.; Finley, J. P. [Department of Physics, Purdue University, West Lafayette, IN 47907 (United States); Dumm, J.; Fortson, L. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); Errando, M. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Falcone, A. [Department of Astronomy and Astrophysics, 525 Davey Lab, Pennsylvania State University, University Park, PA 16802 (United States); Federici, S. [DESY, Platanenallee 6, D-15738 Zeuthen (Germany); Finnegan, G., E-mail: qfeng@purdue.edu, E-mail: cui@purdue.edu [Department of Physics and Astronomy, University of Utah, Salt Lake City, UT 84112 (United States); Collaboration: VERITAS Collaboration; and others

    2013-01-10

    We report on the detection of a very rapid TeV gamma-ray flare from BL Lacertae on 2011 June 28 with the Very Energetic Radiation Imaging Telescope Array System (VERITAS). The flaring activity was observed during a 34.6 minute exposure, when the integral flux above 200 GeV reached (3.4 {+-} 0.6) Multiplication-Sign 10{sup -6} photons m{sup -2} s{sup -1}, roughly 125% of the Crab Nebula flux measured by VERITAS. The light curve indicates that the observations missed the rising phase of the flare but covered a significant portion of the decaying phase. The exponential decay time was determined to be 13 {+-} 4 minutes, making it one of the most rapid gamma-ray flares seen from a TeV blazar. The gamma-ray spectrum of BL Lacertae during the flare was soft, with a photon index of 3.6 {+-} 0.4, which is in agreement with the measurement made previously by MAGIC in a lower flaring state. Contemporaneous radio observations of the source with the Very Long Baseline Array revealed the emergence of a new, superluminal component from the core around the time of the TeV gamma-ray flare, accompanied by changes in the optical polarization angle. Changes in flux also appear to have occurred at optical, UV, and GeV gamma-ray wavelengths at the time of the flare, although they are difficult to quantify precisely due to sparse coverage. A strong flare was seen at radio wavelengths roughly four months later, which might be related to the gamma-ray flaring activities. We discuss the implications of these multiwavelength results.

  6. Rapid Synchrotron Flares from BL Lacertae Detected by ASCA and RXTE

    CERN Document Server

    Tanihata, C; Kataoka, J; Madejski, G M; Inoue, S; Kubo, H; Makino, F; Mattox, J R; Kawai, N

    2000-01-01

    We report the variable X-ray emission from BL Lacertae detected in the ASCA ToO observation conducted during the EGRET and RXTE pointings, coincident with the 1997 July outburst. The source showed a historically high state of X-ray, optical, and gamma-ray emission, with its 2-10 keV flux peaking at ~3.3 E-11 erg/cm2/s. This is more than 3 times higher than the value measured by ASCA in 1995. We detected two rapid flares which occured only in the soft X-ray band, while the hard X-ray flux also increased, but decayed with a much longer time scale. Together with the requirement of a very steep and varying power law dominating the soft X-ray band in addition to the hard power law, we suggest that both the high energy end of the synchrotron spectrum and the hard inverse Compton spectrum were visible in this source during the outburst. We discuss the possible origins of the observed variability time scales, and interpret the short time scales of the soft X-ray variability as reflecting the size of the emission regi...

  7. The awakening of BL Lacertae: observations by Fermi, Swift, and the GASP-WEBT

    CERN Document Server

    Raiteri, C M; D'Ammando, F; Larionov, V M; Gurwell, M A; Mirzaqulov, D O; Smith, P S

    2013-01-01

    Since the launch of the Fermi satellite, BL Lacertae has been moderately active at gamma-rays and optical frequencies until May 2011, when the source started a series of strong flares. The exceptional optical sampling achieved by the GLAST-AGILE Support Program (GASP) of the Whole Earth Blazar Telescope (WEBT) in collaboration with the Steward Observatory allows us to perform a detailed comparison with the daily gamma-ray observations by Fermi. Discrete correlation analysis between the optical and gamma-ray emission reveals correlation with a time lag of 0 +- 1 d, which suggests cospatiality of the corresponding jet emitting regions. A better definition of the time lag is hindered by the daily gaps in the sampling of the extremely fast flux variations. In general, optical flares present more structure and develop on longer time scales than corresponding gamma-ray flares. Observations at X-rays and at millimetre wavelengths reveal a common trend, which suggests that the region producing the mm and X-ray radiat...

  8. Optically Selected BL Lacertae Candidates from the Sloan Digital Sky Survey Data Release Seven

    CERN Document Server

    Plotkin, Richard M; Brandt, W N; Diamond-Stanic, A M; Fan, X; Hall, P B; Kimball, A E; Richmond, M W; Schneider, D P; Shemmer, O; Voges, W; York, D G; Bahcall, N A; Snedden, S; Bizyaev, D; Brewington, H; Malanushenko, V; Malanushenko, E; Oravetz, D; Pan, K; Simmonds, A

    2009-01-01

    We present a sample of 723 optically selected BL Lac candidates from the SDSS DR7 spectroscopic database encompassing 8250 deg^2 of sky; our sample constitutes one of the largest uniform BL Lac samples yet derived. Each BL Lac candidate has a high-quality SDSS spectrum from which we determine spectroscopic redshifts for ~60% of the objects. Redshift lower limits are estimated for the remaining objects utilizing the lack of host galaxy flux contamination in their optical spectra; we find that objects lacking spectroscopic redshifts are likely at systematically higher redshifts. Approximately 80% of our BL Lac candidates match to a radio source in FIRST/NVSS, and ~40% match to a ROSAT X-ray source. The homogeneous multiwavelength coverage allows subdivision of the sample into 637 radio-loud BL Lac candidates and 86 weak-featured radio-quiet objects. The radio-loud objects broadly support the standard paradigm unifying BL Lac objects with beamed radio galaxies. We propose that the majority of the radio-quiet obj...

  9. Comparison between TeV and non-TeV BL Lac Objects

    CERN Document Server

    Lin, C

    2016-01-01

    BL Lacertae objects (BL Lacs) is the dominant population of TeV emitting blazars. In this work, we investigate whether there is any special observational properties for TeV sources. To do so, we will compare the observational properties of TeV detected BL Lacs (TeV BLs) and non-TeV detected BL Lac objects (non-TeV BLs). From the 3rd $Fermi$/LAT catalog (3FGL), we can get 662 BL Lacs, out of which, 47 are TeV BLs and 615 are non-TeV BLs. Their multi-wavelength flux densities ($F_{\\rm R}$, $F_{\\rm O}$, $F_{\\rm X}$, $F_{\\gamma}$), photon spectral indexes ($\\alpha_{\\rm X}^{\\rm ph}$, $\\alpha_{\\gamma}^{\\rm ph}$), and effective spectral indexes ($\\alpha_{\\rm RO}$ and $\\alpha_{\\rm OX}$) are compiled from the available literatures. Then the luminosities ($\\log\\,{\

  10. Multifrequency observations of the BL Lacertae object 0735+178

    Science.gov (United States)

    Bregman, J. N.; Glassgold, A. E.; Huggins, P. J.; Aller, H. D.; Aller, M. F.; Hodge, P. E.; Rieke, G. H.; Lebofsky, M. J.; Pollock, J. T.; Pica, A. J.

    1984-01-01

    In each of the present four simultaneous spectra covering the radio-through-X-ray regimes, the IR-UV synchrotron continuum dominates the total observed power and presumably becomes opague between 10 to the 11th and 10 to the 13th Hz. Nonsimultaneous observations were also conducted, over a longer time period, in order to study long- and short-term variability at X-ray, optical, and radio frequencies. These data indicate that the rapid and dramatic variations evident at IR and optical wavelengths are absent at radio and X-ray frequencies, supporting a view of IR-UV flux emanation from a small region, while the X-rays are produced by the inverse Compton process in the radio-emitting region. Particles, photons and magnetic field may not be far from equipartition in this region. Theoretical suggestions are developed regarding the radial behavior of the electron density and magnetic field.

  11. Ondas de choque em jatos de quasares e objetos BL Lacertae

    Science.gov (United States)

    Melo, F. E.; Botti, L. C. L.

    2003-08-01

    Este trabalho é parte de um projeto que vem sendo realizado há dois anos no CRAAM, cujos objetivos principais são analisar e aplicar um modelo generalizado de ondas de choque em jatos relativísticos de plasma, presentes em quasares e objetos BL Lacertae, para explicar a variabilidade observada nestes objetos. O método consiste em uma decomposição de curvas de luz em séries de explosões similares, em várias freqüências, baseando-se em uma evolução espectro-temporal média das explosões. A partir da evolução média, um ajuste de cada explosão é feito com base em equações empíricas, modificando-se apenas parâmetros específicos de cada explosão. Inicialmente o modelo foi aplicado ajustando-se as curvas de luz a explosões delineadas por uma evolução do choque em três estágios, segundo a predominância do processo de emissão: síncrotron, Compton e adiabático. Entretanto, nesta nova fase de projeto, visando uma parametrização mais concisa, uma otimização do algoritmo de ajuste e uma convergência mais rápida, a formulação para cada evento foi assumida com uma evolução em apenas dois estágios: subida e descida. Isto possibilitou uma ótima delineação das curvas de luz das fontes OV236, OJ287, 3C273 e BL Lac, entre 1980 e 2000, nas freqüências 4.8, 8.0, 14.5 e 22 GHz, utilizando-se dados do Observatório da Universidade de Michigan, do Observatório do Itapetinga (Atibaia SP) e do Observatório Metsähovi. Como conclusões importantes, verificou-se que: os parâmetros ajustados descrevem o comportamento do jato; os valores do índice que descreve a expansão do jato sugerem que o mesmo se expande de uma forma não-cônica; o campo magnético é turbulento atrás da frente de choque; e as peculiaridades das explosões são devidas à influência de grandezas tais como o coeficiente da distribuição espectral de energia dos elétrons, a intensidade de campo magnético e o fator de feixe Doppler, no início do choque.

  12. Whipple Observations of BL Lac Objects

    CERN Document Server

    D'Vali, M; Bradbury, S M; Buckley, J H; Burdett, A M; Carter-Lewis, D A; Catanese, M; Cawley, M F; Fegan, D J; Fegan, S J; Finley, J P; Gaidos, J A; Hall, T A; Hillas, A M; Knapp, J; Krennrich, F; Le Bohec, S; Lessard, R W; Masterson, C; Myles, S D; Quinn, J; Rose, H J; Samuelson, F W; Sembroski, G H; Vasilev, V; Weekes, T C

    1999-01-01

    Only BL Lac objects have been detected as extragalactic sources of very high energy (E > 300 GeV) gamma rays. Using the Whipple Observatory Gamma-ray Telescope, we have attempted to detect more BL Lacs using three approaches. First, we have conducted surveys of nearby BL Lacs, which led to the detections of Mrk 501 and 1ES 2344+514. Second, we have observed X-ray bright BL Lacs when the RXTE All-Sky Monitor identifies high state X-ray emission in an object, in order to efficiently detect extended high emission states. Third, we have conducted rapid observations of several BL Lacs and QSOs located close together in the sky to search for very high flux, short time-scale flare states such as have been seen from Mrk 421. We will present the results of a survey using the third observational technique.

  13. Optically selected BL Lacertae candidates from the Sloan Digital Sky Survey Data Release Seven

    NARCIS (Netherlands)

    R.M. Plotkin; S.F. Anderson; W.N. Brandt; A.M. Diamond-Stanic; X. Fan; P.B. Hall; A.E. Kimball; M.W. Richmond; D.P. Schneider; O. Shemmer; W. Voges; D.G. York; N.A. Bahcall; S. Snedden; D. Bizyaev; H. Brewington; V. Malanushenko; E. Malanushenko; D. Oravetz; K. Pan; A. Simmons

    2010-01-01

    We present a sample of 723 optically selected BL Lac candidates from the Sloan Digital Sky Survey Data Release 7 (SDSS DR7) spectroscopic database encompassing 8250 deg(2) of sky; our sample constitutes one of the largest uniform BL Lac samples yet derived. Each BL Lac candidate has a high-quality S

  14. Very high energy observations of the BL Lac objects 3C 66A and OJ 287

    CERN Document Server

    Lindner, T; Kildea, J; Ball, J; Bramel, D A; Carson, J; Covault, C E; Driscoll, D; Fortin, P; Gingrich, D M; Jarvis, A; Müller, C; Mukherjee, R; Ong, R A; Ragan, K; Scalzo, R A; Williams, D A; Zweerink, J

    2007-01-01

    Using the Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE), we have observed the BL Lac objects 3C 66A and OJ 287. These are members of the class of low-frequency-peaked BL Lac objects (LBLs) and are two of the three LBLs predicted by Costamante and Ghisellini to be potential sources of very high energy (>100 GeV) gamma-ray emission. The third candidate, BL Lacertae, has recently been detected by the MAGIC collaboration. Our observations have not produced detections; we calculate a 99% CL upper limit of flux from 3C 66A of 0.15 Crab flux units and from OJ 287 our limit is 0.52 Crab. These limits assume a Crab-like energy spectrum with an effective energy threshold of 185 GeV.

  15. Intermediate Scale Structures in BL Lac objects

    CERN Document Server

    Reynolds, C; Gabuzda, D C

    2004-01-01

    The parsec-scale total intensity structures of BL Lac objects share many characteristics with quasars: e.g. well-collimated jets and superluminal motion. However, the jets of BL Lac objects appear to fade much more quickly than those in quasars and on VLA scales many BL Lacs have structures comparable to those of low luminosity (FR I) radio galaxies, in which kpc-scale flow speeds are non-relativistic. The region between parsec and kiloparsec scales is therefore one of transition in BL Lac objects. We have carried out VLBI observations of a small sample of BL Lac objects at frequencies between 2.3 GHz and 327 MHz in order to investigate this transition region. Preliminary results for two of these sources are presented here. Coherent structures are detected in these sources out to a distance of several tens of parsecs. We find evidence for significant changes in jet structure on scales of a few tens of milliarcseconds, both in terms of the orientation and collimation of the jets.

  16. Structure and flux variability in the VLBI jet of BL Lacertae during the WEBT campaigns (1995--2004)

    CERN Document Server

    Bach, U; Raiteri, C M; Agudo, I; Aller, H D; Aller, M F; Denn, G; Gómez, J L; Jorstad, S; Marscher, A; Mutel, R L; Terasranta, H

    2006-01-01

    BL Lacertae has been the target of several observing campaigns by the Whole Earth Blazar Telescope (WEBT) collaboration and is one of the best studied blazars at all accessible wavelengths. A recent analysis of the optical and radio variability indicates that part of the radio variability is correlated with the optical light curve. Here we present an analysis of a huge VLBI data set including 108 images at 15, 22, and 43 GHz obtained between 1995 and 2004. The aim of this study is to identify the different components contributing to the single-dish radio light curves. We obtain separate radio light curves for the VLBI core and jet and show that the radio spectral index of single-dish observations can be used to trace the core variability. Cross-correlation of the radio spectral index with the optical light curve indicates that the optical variations lead the radio by about 100 days at 15 GHz. By fitting the radio time lags vs. frequency, we find that the power law is steeper than expected for a freely expandi...

  17. Studies of the Jet in BL Lacertae I. Recollimation Shock and Moving Emission Features

    CERN Document Server

    Cohen, M H; Arshakian, T G; Homan, D C; Hovatta, T; Kovalev, Y Y; Lister, M L; Pushkarev, A B; Richards, J L; Savolainen, T

    2014-01-01

    Parsec-scale VLBA images of BL Lac at 15 GHz show that the jet contains a permanent quasi-stationary emission feature 0.26 mas (0.34 pc projected) from the core, along with numerous moving features. In projection, the tracks of the moving features cluster around an axis at position angle -166.6 deg that connects the core with the standing feature. The moving features appear to emanate from the standing feature in a manner strikingly similar to the results of numerical 2-D relativistic magneto-hydrodynamic (RMHD) simulations in which moving shocks are generated at a recollimation shock. Because of this, and the close analogy to the jet feature HST-1 in M87, we identify the standing feature in BL Lac as a recollimation shock. We assume that the magnetic field dominates the dynamics in the jet, and that the field is predominantly toroidal. From this we suggest that the moving features are compressions established by slow and fast mode magneto-acoustic MHD waves. We illustrate the situation with a simple model in...

  18. Studies of the Jet in BL Lacertae. II. Superluminal Alfv\\'en Waves

    CERN Document Server

    Cohen, M H; Arshakian, T G; Clausen-Brown, E; Homan, D C; Hovatta, T; Kovalev, Y Y; Lister, M L; Pushkarev, A B; Richards, J L; Savolainen, T

    2014-01-01

    Ridge lines on the pc-scale jet of the active galactic nucleus BL Lac display transverse patterns that move superluminally downstream. The patterns are not ballistic, but are analogous to waves on a whip. Their apparent speeds $\\beta_\\mathrm{app}$ (units of $c$) range from 4.2 to 13.5, corresponding to $\\beta_\\mathrm{wave}^\\mathrm{gal}= 0.981 - 0.998$ in the galaxy frame. We show that the magnetic field in the jet is well-ordered with a strong transverse component, and assume that it is helical and that the transverse patterns are longitudinal Alfv\\'en waves. The wave-induced transverse speed of the jet is non-relativistic ($\\beta_\\mathrm{tr}^\\mathrm{gal}\\sim 0.09$) and in agreement with our assumption of low-amplitude waves. In 2010 the wave activity subsided and the jet displayed a mild wiggle that had a complex oscillatory behavior. The waves are excited by changes in the position angle of the recollimation shock, in analogy to exciting a wave on a whip by shaking it. Simple models of the system are presen...

  19. Probing the innermost regions of AGN jets and their magnetic fields with RadioAstron. I. Imaging BL Lacertae at 21 microarcsecond resolution

    CERN Document Server

    Gómez, José L; Bruni, Gabriele; Kovalev, Yuri Y; Marscher, Alan P; Jorstad, Svetlana G; Mizuno, Yosuke; Bach, Uwe; Sokolovsky, Kirill V; Anderson, James M; Galindo, Pablo; Kardashev, Nikolay S; Lisakov, Mikhail M

    2016-01-01

    We present the first polarimetric space VLBI imaging observations at 22 GHz. BL Lacertae was observed in 2013 November 10 with the RadioAstron space VLBI mission, including a ground array of 15 radio telescopes. The instrumental polarization of the space radio telescope is found to be within 9%, demonstrating the polarimetric imaging capabilities of RadioAstron at 22 GHz. Ground-space fringes were obtained up to a projected baseline distance of 7.9 Earth's diameters in length, allowing us to image the jet in BL Lacertae with a maximum angular resolution of 21 $\\mu$as, the highest achieved to date. We find evidence for emission upstream of the radio core, which may correspond to a recollimation shock at about 40 $\\mu$as from the jet apex, in a pattern that includes other recollimation shocks at approximately 100 $\\mu$as and 250 $\\mu$as from the jet apex. Polarized emission is detected in two components within the innermost 0.5 mas from the core, as well as in some knots 3 mas downstream. Faraday rotation analy...

  20. The Megaparsec-Scale X-ray Jet of the BL Lac Object OJ287

    CERN Document Server

    Marscher, Alan P

    2010-01-01

    We present an X-ray image of the BL Lacertae object OJ287 revealing a long jet, curved by 55 degrees and extending 20 arcsec from the nucleus. This corresponds to a projected separation from the nucleus of 90 kpc, which de-projects to > 1 Mpc based on the viewing angle on parsec scales. Radio emission follows the general X-ray morphology but extends even farther from the nucleus. The upper limit to the isotropic radio luminosity, ~ 2E24 W/Hz, places the source in the Fanaroff-Riley 1 (FR 1) class, as expected for BL Lac objects. If the X-ray emission is from inverse Compton scattering of cosmic microwave background photons, as indicated by the spectral energy distribution, we derive a magnetic field B ~ 5 microgauss, minimum electron energy of 7-40mc^2, and Doppler factor of about 8 in a knot about 8 arcsec from the nucleus. The minimum total kinetic power of the jet is 1-2E45 erg/s, similar to the FR 1 radio galaxy 3C 120. The Doppler factor on parsec scales is about 2.5 times the value derived for the exten...

  1. Is Low-Frequency-Peaked BL Lac Object OJ 287 a TeV Emitter?

    Institute of Scientific and Technical Information of China (English)

    CHEN Liang; BAI Jin-Ming

    2010-01-01

    @@ It is well known that there are only two low-frequency-peaked BL Lac objects(LBLs:BL Lacertae and S5 0716+714)and one flat spectrum radio quasar(FSRQ:3C 279)among more than 30 active galactic nuclei (AGNs)with detected TeV emissions.We study the spectral energy distribution(SED)of a famous LBL OJ 287,whose light curve has a 12-y period.Using a homogeneous one-zone synchrotron + synchrotron-self Compton model,we model the quasi-simultaneous broad-band SED of OJ 287.With some reasonable assumptions,we extrapolate the model to the high state of OJ 287 and predict its γ-ray emissions.Taking into account the absorption of γ-ray by the extragalactic background light(EBL),we find that the TeV emission of OJ 287 in high state is slightly higher than the sensitivity of H.E.S.S.The study on SEDs of OJ 287 has implications to unveil the origin of jet activity during its 12-y period and the properties of EBL.

  2. Black hole masses of BL Lac objects

    OpenAIRE

    J. K. Kotilainen; Falomo, R.; Treves, A.

    2002-01-01

    The correlation between black hole mass M(BH) and the central stellar velocity dispersion sigma in nearby elliptical galaxies affords a novel way to determine M(BH) in active galaxies. We report on measurements of sigma from optical spectra of 7 BL Lac host galaxies. The range of sigma (160 - 290 km/s) corresponds to estimated M(BH) of 5 x 10^7 - 9 x 10^8 Mo. The average ratio of M(BH) to the host galaxy mass is 1.4 x 10^-3, consistent with that estimated in other active and inactive galaxies...

  3. The Megaparsec-scale X-ray Jet of The BL Lac Object OJ287

    Science.gov (United States)

    Marscher, Alan P.; Jorstad, Svetlana G.

    2011-03-01

    We present an X-ray image of the BL Lacertae (BL Lac) object OJ287 revealing a long jet, curved by 55° and extending 20'' or 90 kpc from the nucleus. This de-projects to >1 Mpc based on the viewing angle on parsec scales. Radio emission follows the general X-ray morphology but extends even farther from the nucleus. The upper limit to the isotropic radio luminosity, ~2 × 1024 W Hz-1, places the source in the Fanaroff-Riley 1 (FR 1) class, as expected for BL Lac objects. The spectral energy distribution indicates that the extended X-ray emission is from inverse Compton scattering of cosmic microwave background photons. In this case, the derived magnetic field is B ≈ 5 μG, the minimum electron energy is 7-40m e c 2, and the Doppler factor is δ ≈ 8 in a knot 8'' from the nucleus. The minimum total kinetic power of the jet is (1-2)×1045 erg s-1. Upstream of the bend, the width of the X-ray emission in the jet is about half the projected distance from the nucleus. This implies that the highly relativistic bulk motion is not limited to an extremely thin spine, as has been proposed previously for FR 1 sources. The bending of the jet, the deceleration of the flow from parsec to kiloparsec scales, and the knotty structure can all be caused by standing shocks inclined by ~7° to the jet axis. Moving shocks resulting from major changes in the flow properties can also reproduce the knotty structure, but such a model does not explain as many of the observational details.

  4. Variabilidade óptica de longo período e precessão de jato: o caso de BL Lacertae

    Science.gov (United States)

    Caproni, A.; Abraham, Z.

    2003-08-01

    Variabilidade é tipicamente uma característica de AGNs, sendo observada em toda a faixa eletromagnética. Em relação às escalas de tempo, variações desde horas até de algumas décadas foram encontradas por vários autores. Em alguns casos, análises temporais de curvas de luz mostram a existência de periodicidade nas variações observadas. Um exemplo de objeto que preenche as características mencionadas acima é BL Lacertae, o protótipo da classe BL Lac dos AGNs. Neste trabalho, nós interpretamos a variabilidade periódica de longo período detectada na curva de luz na banda B (~7,5 anos) como o resultado da periodicidade na amplificação da radiação oriunda do jato relativístico. Neste cenário, a amplificação periódica seria induzida pela precessão, que muda o ângulo entre o jato e a linha de visada. Com esta abordagem e vínculos adicionais fornecidos por observações em altas energias, nós podemos impor limites para os parâmetros do modelo de precessão, tais como o fator de Lorentz associado ao movimento global do jato, o ângulo de abertura do cone de precessão e o ângulo entre o eixo do cone e a linha de visada.

  5. Radio Detection of 18 RASS BL Lac Objects

    Directory of Open Access Journals (Sweden)

    Anderson M. W. B.

    2009-12-01

    Full Text Available We present the radio detection of 18 BL Lac objects from oursurvey of over 575 deg$^2$ of sky. These 18 objects are located within$20arcsec$ of the X-ray position, of which 11 have a measuredred-shift. All candidates are radio emitters above $sim$1 mJy and fall within the range of existing samples on the two colour, $alpha _mathrm{RO}$ vs $alpha _mathrm{OX}$, diagram with a transitional population of three evident. Two unusual sources have been identified, a candidate radio quiet BL Lac, RX J0140.9-4130, and an extreme HBL, RX J0109.9-4020, with $log( u _mathrm{peak}approx 19.2$. The BL Lac $log(N-log(S$ relation is consistent with other samples and indicates the ROSAT All Sky Survey (RASS could contain ($2000{pm}400$ BL Lac objects.

  6. Optical and radio variability of the BL Lac object AO 0235+16 a possible 5-6 year periodicity

    CERN Document Server

    Raiteri, C M; Aller, H D; Aller, M F; Heidt, J; Kurtanidze, O M; Lanteri, L; Maesano, M; Massaro, E; Montagni, F; Nesci, R; Nilsson, K; Nikolashvili, M G; Nurmi, P; Ostorero, L; Pursimo, T; Rekola, R; Sillanpää, A; Takalo, L O; Terasranta, H; Tosti, G; Balonek, T J; Feldt, M; McGrath, E J; Heines, A; Heisler, C A; Hu, J; Kidger, M; Mattox, J R; Pati, A K; Robb, R; Sadun, A C; Shastri, P; Wagner, S J; Wei, J; Wu, X

    2001-01-01

    New optical and radio data on the BL Lacertae object AO 0235+16 have been collected in the last four years by a wide international collaboration, which confirm the intense activity of this source. The optical data also include the results of the Whole Earth Blazar Telescope (WEBT) first-light campaign organized in November 1997. The optical spectrum is observed to basically steepen when the source gets fainter. We have investigated the existence of typical variability time scales and of possible correlations between the optical and radio emissions by means of visual inspection, Discrete Correlation Function analysis, and Discrete Fourier Transform technique. The major radio outbursts are found to repeat quasi-regularly with a periodicity of about 5.7 years; this period is also in agreement with the occurrence of some of the major optical outbursts, but not all of them.

  7. HESS J1943+213: a candidate extreme BL Lacertae object

    CERN Document Server

    Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Balzer, A; Barnacka, A; de Almeida, U Barres; Bazer-Bachi, A R; Becherini, Y; Becker, J; Behera, B; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Borrel, V; Brucker, J; Brun, F; Brun, P; Bulik, T; Büsching, I; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L -M; Clapson, A C; Coignet, G; Colom, P; Conrad, J; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fiasson, A; Fontaine, G; Förster, A; Fü\\ssling, M; Gallant, Y A; Gast, H; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Häffner, S; Hague, J D; Hampf, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Keogh, D; Khangulyan, D; Khélifi, B; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Laffon, H; Lamanna, G; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maurin, D; Maxted, N; McComb, T J L; Medina, M C; Méhault, J; Nguyen, N; Moderski, R; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Panter, M; Arribas, M Paz; Pedaletti, G; Pelletier, G; Petrucci, P -O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Rayner, S M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Ryde, F; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schönwald, A; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Spengler, G; Stawarz, \\L; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tibolla, O; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Viana, A; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; Wierzcholska, A; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S; Burnett, T H; Hill, A B

    2011-01-01

    We report on a newly detected point-like source, HESS J1943+213 located in the Galactic plane. This source coincides with an unidentified hard X-ray source IGR J19443+2117, which was proposed to have radio and infrared counterparts. HESS J1943+213 is detected at the significance level of 7.9 \\sigma (post-trials) at RA(J2000)=19h 43m 55s +- 1s (stat) +- 1s (sys), DEC(J2000) = +21deg 18' 8" +- 17" (stat) +- 20" (sys). The source has a soft spectrum with photon index Gamma = 3.1 +- 0.3 (stat) +- 0.2 (sys) and a flux above 470 GeV of 1.3 +- 0.2 (stat) +- 0.3 (sys) x 10^{-12} cm^{-2} s^{-1}. There is no Fermi/LAT counterpart down to a flux limit of 6 x 10^{-9} cm^{-2} s^{-1} in the 0.1-100 GeV energy range (95% confidence upper limit calculated for an assumed power-law model with a photon index Gamma=2.0). The data from radio to VHE gamma-rays do not show any significant variability. We combine new H.E.S.S., Fermi/LAT and Nancay Radio Telescope observations with pre-existing non-simultaneous multi-wavelength obser...

  8. Understanding BL Lac objects Structural & kinematic mode changes in the BL Lac object PKS 0735+178

    CERN Document Server

    Britzen, S; Gong, B P; Zhang, J W; Gopal-Krishna,; Goyal, Arti; Aller, M F; Aller, H D; Zensus, J A

    2010-01-01

    Context. We present evidence that parsec-scale jets in BL Lac objects may be significantly distinct in kinematics from their counterparts in quasars. We argued this previously for the BL lac sources 1803+784 and 0716+714, report here a similar pattern for another well-known BL Lac object, PKS 0735+178, whose nuclear jet is found to exhibit kinematics atypical of quasars. Aims. A detailed study of the jet components' motion reveals that the standard AGN paradigm of apparent superluminal motion does not always describe the kinematics in BL Lac objects. We study 0735+178 here to augment and improve the understanding of the peculiar motions in the jets of BL Lac objects as a class. Methods. We analyzed 15 GHz VLBA (Very Long Baseline Array) observations (2cm/MOJAVE survey) performed at 23 epochs between 1995.27 and 2008.91. Results. We found a drastic structural mode change in the VLBI jet of 0735+178, between 2000.4 and 2001.8 when its twice sharply bent trajectory turned into a linear shape.We further found tha...

  9. VLBI observations of seven BL Lac objects from RGB sample

    CERN Document Server

    Wu, Zhongzu; Gu, Minfeng; Liu, Yi

    2007-01-01

    We present EVN observations of seven BL Lac objects selected from the RGB sample. To investigate the intrinsic radiation property of BL Lac objects, we estimated the Doppler factor with the VLA or MERLIN core and the total 408 MHz luminosity for a sample of 170 BL Lac objects. The intrinsic (comoving) synchrotron peak frequency was then calculated by using the estimated Doppler factor. Assuming a Lorentz factor of 5, the viewing angle of jets was constrained. The high-resolution VLBI images of seven sources all show a core-jet structure. We estimated the proper motions of three sources with the VLBI archive data, and find that the apparent speed increases with the distance of components to the core for all of them. In our BL Lacs sample, the Doppler factor of LBLs is systematically larger than that of IBLs and HBLs. We find a significant anti-correlation between the total 408 MHz luminosity and the intrinsic synchrotron peak frequency. However, the scatter is much larger than for the blazar sequence. Moreover...

  10. Radio-weak BL Lac Objects in the Fermi Era

    Science.gov (United States)

    Massaro, F.; Marchesini, E. J.; D’Abrusco, R.; Masetti, N.; Andruchow, I.; Smith, Howard A.

    2017-01-01

    The existence of “radio-weak BL Lac objects” (RWBLs) has been an open question, and has remained unsolved since the discovery that quasars could be radio-quiet or radio-loud. Recently, several groups identified RWBL candidates, mostly found while searching for low-energy counterparts of the unidentified or unassociated gamma-ray sources listed in the Fermi catalogs. Confirming RWBLs is a challenging task since they could be confused with white dwarfs (WDs) or weak emission line quasars (WELQs) when there are not sufficient data to precisely draw their broadband spectral energy distribution, and their classification is mainly based on a featureless optical spectra. Motivated by the recent discovery that Fermi BL Lacs appear to have very peculiar mid-IR emission, we show that it is possible to distinguish between WDs, WELQs, and BL Lacs using the [3.4]–[4.6]–[12] μm color–color plot built using the WISE magnitudes when the optical spectrum is available. On the basis of this analysis, we identify WISE J064459.38+603131 and WISE J141046.00+740511.2 as the first two genuine RWBLs, both potentially associated with Fermi sources. Finally, to strengthen our identification of these objects as true RWBLs, we present multifrequency observations for these two candidates to show that their spectral behavior is indeed consistent with that of the BL Lac population.

  11. Variability of the Blazar BL Lac in 2001

    Science.gov (United States)

    Barnaby, D.; Carini, M.; Wills, W.; Atkerson, A.; Monroe, T.; Ryle, W.

    2002-06-01

    BL Lacertae (z=0.0686) is the archetype of a class of active galactic nuclei known as BL Lacertae objects. BL Lacertae objects are a branch of the class of objects known as blazars, and BL Lac is one of the best-observed blazars. It exhibits large amplitude (> 1 mag) variability at optical wavelengths over years, months, and weeks. In the last few years, BL Lac has returned to a highly active state, and a concerted effort is being made to discern the mechanism(s) responsible for this high-degree of variability. To do this many observatories have begun to monitor BL Lacertae regularly in an attempt to measure the light curve 24-hours per day in a collaboration called the Whole Earth Blazar Telescope (WEBT). To date the WEBT results show an approximately 7-hour time scale for short outbursts and suggest a measurable distinction between spectral changes during low-brightness and out-burst phases. Western Kentucky University's Bell Astrophysical Observatory began regularly monitoring BL Lacertae in the latter half of 2001 with our newly refurbished 0.6meter telescope. We present an R-band light curve derived from photometric CCD observations covering the monitoring period. Generally, the light curve ranges between R=13.6-14.4, which is similar to the range measured by WEBT observers during the low-brightness phase in 2000. In addition to the long-term light curve, we present R-band microvariability light curves derived from persistent monitoring over 2 different nights during the same period. These show monotonic changes in R-band brightness of up 0.25 magnitudes over 3 hours. We gratefully acknowledge NASA for funding this research through grant NAG5-8762, and Western Kentucky University for funds provided through the Applied Research and Technology Program of Distinction.

  12. Optical polarization of high-energy BL Lac objects

    CERN Document Server

    Hovatta, T; Blinov, D; Pavlidou, V; Nilsson, K; Kiehlmann, S; Angelakis, E; Ramazani, V Fallah; Liodakis, I; Myserlis, I; Panopoulou, G V; Pursimo, T

    2016-01-01

    We investigate the optical polarization properties of high-energy BL Lac objects using data from the RoboPol blazar monitoring program and the Nordic Optical Telescope. We wish to understand if there are differences in the BL Lac objects that are detected with the current-generation TeV instruments compared to those that have not yet been detected. The mean polarization fraction of the TeV-detected BL Lacs is 5% while the non-TeV sources show a higher mean polarization fraction of 7%. This difference in polarization fraction disappears when the dilution by the unpolarized light of the host galaxy is accounted for. The TeV sources show somewhat lower fractional polarization variability amplitudes than the non-TeV sources. Also the fraction of sources with a smaller spread in the Q/I - U/I -plane and a clumped distribution of points away from the origin, possibly indicating a preferred polarization angle, is larger in the TeV than in the non-TeV sources. These differences between TeV and non-TeV samples seems t...

  13. "Oscillating" components in the BL Lac object 0716+714?

    CERN Document Server

    Britzen, S; Witzel, A; Agudo, I; Aller, M F; Aller, H D; Eckart, A; Zensus, J A

    2006-01-01

    15 VLBA observations of the BL Lac object 0716+714, performed between 1994.67 and 2006.40 at 15 GHz, have been analyzed. Part of the data (12 epochs) were obtained within the Mojave-survey project and reanalyzed by us. We present a new motion scenario for jet model component motion in this source which suggests that no longterm-outward motion but rather an oscillation of components around an average core separation is taking place. Although no significant outward motion in the core separation can be found, motion with regard to the position angle is observed. We give lower limits for the derived apparent motions and Doppler factors and compare them with values published in the literature. We find a relation between the total flux-density evolution at 14.5 GHz (UMRAO data) and the position angle changes observed for the jet component closest to the core. We suggest a significant geometric contribution to the longterm flux-density variability in 0716+714.

  14. Quasi-simultaneous observations of the BL Lac object MK 501 in X-ray, UV, visible, IR and radio frequencies

    Science.gov (United States)

    Kondo, D. M.; Worrall, D. M.; Mushotzky, R. F.; Hackney, R. L.; Hackney, K. H.; Oke, J. B.; Yee, H.; Neugebauer, G.; Matthews, K.; Feldman, P. A.

    1980-01-01

    Quasi-simultaneous observations of the BL Lacertae (Lac) objects MK 501 were performed for the first time at X-ray, ultraviolet, visible, infrared, and radio frequencies. The observed spectral slope from the X-ray to UV regions is positive and continuous, but that from the mid UV to visible light region becomes gradually flat and possibly turns down toward lower frequencies; the optical radio emission can not be accounted for by a single power law. Several theoretical models were considered for the emission mechanism. A quantitative comparison was performed with the synchrotron-self-Compton model; the total spectrum is found consistent with this model. The spectrum from visible light to X-ray is consistent with synchrotron radiation or with inverse-Compton scattering by a hot thermal cloud of electrons. The continuity of the spectral slope from X-ray to UV implied by the current data suggests that the previous estimates of the total luminosity of this BL Lac object is underestimated by a factor of about three or four.

  15. Gamma-ray Emission from the γ-ray-loud BL Lac Objects

    Institute of Scientific and Technical Information of China (English)

    2001-01-01

    Using the HST observation data of BL Lac objects by Urry et al. and γγ-ray observation data, we find that there is a correlation between Fγ and FO nucleifor γ-ray-loud BL Lac objects (correlation coefficients: γ = 0.63,p = 4.0 × 10-2),but no correlation between Fγ and Fohost, where FO nuclei and Fohost are the fluxes ofnuclei and host galaxy in V-band. For 19 γ-ray-loud BL Lac objects with observedspectral index in multi-wavebands, the spectral index correlations between any twobands are as follow: (1) there is a strong correlation between αγ and αK for 15 BLLac objects(γ = 0.84,p = 3.11 × 10-4); (2) the correlation between αγ and αo for12 BL Lac objects is γ = 0.82,p = 1.5 × 10-3; (3) there is no correlation betweenαγ and αx for 16 BL Lac objects. The results, together with characteristic double-humped shape of their SEDs, show that the synchrotron self-Compton mechanismmight be a main mechanism for the γ-ray emission of the BL Lac objects. Theelectrons emitting IR and optical radiation via synchrotron are also responsible forupscattering these photons to γ-rays, and a variability in IR-optical regime shouldbe accompanied by a change in the γ-rays.

  16. VERITAS Discovery of >200GeV Gamma-ray Emission from the Intermediate-frequency-peaked BL Lac Object W Comae

    CERN Document Server

    Acciari, V A; Beilicke, M; Benbow, W; Bradbury, S M; Buckley, J H; Bugaev, V; Butt, Y; Celik, O; Cesarini, A; Ciupik, L; Chow, Y C K; Cogan, P; Colin, P; Cui, W; Daniel, M K; Ergin, T; Falcone, A D; Fegan, S J; Finley, J P; Finnegan, G; Fortin, P; Fortson, L F; Furniss, A; Gall, D; Gillanders, G H; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Hays, E; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, Philip; Karlsson, N; Kertzman, M; Kieda, D B; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Lee, K; Maier, G; McCann, A; McCutcheon, M; Moriarty, P; Mukherjee, R; Nagai, T; Niemiec, J; Ong, R A; Pandel, D; Perkins, J S; Petry, D; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, H J; Schroedter, M; Sembroski, G H; Smith, A W; Steele, D; Swordy, S P; Toner, J A; Vasilev, V V; Wagner, R; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; White, R J; Williams, D A; Wissel, S A; Wood, M; Zitzer, B

    2008-01-01

    We report the detection of very high-energy gamma-ray emission from the intermediate-frequency-peaked BL Lacertae object W Comae (z=0.102) by VERITAS. The source was observed between January and April 2008. A strong outburst of gamma-ray emission was measured in the middle of March, lasting for only four days. The energy spectrum measured during the two highest flare nights is fit by a power-law and is found to be very steep, with a differential photon spectral index of Gamma = 3.81 +- 0.35_stat +- 0.34_syst. The integral photon flux above 200GeV during those two nights corresponds to roughly 9% of the flux from the Crab Nebula. Quasi-simultaneous Swift observations at X-ray energies were triggered by the VERITAS observations. The spectral energy distribution of the flare data can be described by synchrotron-self-Compton (SSC) or external-Compton (EC) leptonic jet models, with the latter offering a more natural set of parameters to fit the data.

  17. The host galaxies of BL Lac objects in the near-infrared

    CERN Document Server

    Kotilainen, J K; Scarpa, R

    1998-01-01

    We present the results of near-infrared H band (1.65 microns) imaging of 11 BL Lac objects with redshifts ranging from z = 0.05 to 0.9. We are able to clearly detect the host galaxy in seven low redshift (z<=0.24) BL Lacs, while the four unresolved BL Lacs have either high or unknown redshift. The galaxies hosting the low redshift BL Lacs are large (average bulge scale length R(e) = 8.8+-9.9 kpc) and luminous (average M(H) = -25.8+-0.5), i.e. slightly brighter than the typical galaxy luminosity L* (M*(H) = -25.0+-0.2), and of similar luminosity to or slightly fainter than brightest cluster galaxies (M(H) = -26.3+-0.3). The average optical/near-infrared colour and colour gradient of the BL Lac hosts (R-H = 2.2+-0.5; d(R-H)/d(log r) = -0.09$+-0.04) are consistent with the hosts being normal ellipticals, indicating that the nuclear activity has only a marginal effect on the star formation history and other properties of the hosts. The BL Lac hosts appear slightly less luminous than those of higher redshift fl...

  18. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R. M.; Markoff, S.; Trager, S. C.; Anderson, S. F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z˜ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  19. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R.M.; Markoff, S.; Trager, S.C.; Anderson, S.F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hole mass -

  20. Dynamical Black Hole Masses of BL Lac Objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, Richard M.; Markoff, Sera; Trager, Scott C.; Anderson, Scott F.

    2012-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey (SDSS) with redshifts out to z ∼ 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black hol

  1. Dynamical black hole masses of BL Lac objects from the Sloan Digital Sky Survey

    NARCIS (Netherlands)

    Plotkin, R. M.; Markoff, S.; Trager, S. C.; Anderson, S. F.

    2011-01-01

    We measure black hole masses for 71 BL Lac objects from the Sloan Digital Sky Survey with redshifts out to z similar to 0.4. We perform spectral decompositions of their nuclei from their host galaxies and measure their stellar velocity dispersions. Black hole masses are then derived from the black h

  2. The physical properties of \\textit{Fermi} TeV BL Lac objects jets

    CERN Document Server

    Ding, N; Xiong, D R; Zhang, H J

    2016-01-01

    We investigate the physical properties of \\textit{Fermi} TeV BL Lac objects jets by modeling the quasi-simultaneous spectral energy distribution of 29 \\textit{Fermi} TeV BL Lacs in the frame of a one-zone leptonic synchrotron self-Compton model. Our main results are the following: (i) There is a negative correlation between $B$ and $\\delta$ in our sample, which suggests that $B$ and $\\delta$ are dependent on each other mainly in Thomson regime. (ii) There are negative correlations between $\

  3. Optical spectroscopy of SDSS J004054.65-0915268: three possible scenarios for the classification. A z \\sim 5 BL Lacertae, blue FSRQ or a weak emission line quasar

    CERN Document Server

    Landoni, M; Bianco, A; Tavecchio, F; Bonnoli, G; Ghisellini, G

    2015-01-01

    The haunt of high redshift BL Lacerate objects is day by day more compelling, to firmly understand their intrinsic nature and evolution. SDSS J004054.65-0915268 is, at the moment, one of the most distant BL Lac candidate at z \\sim 5 (Plotkin et al 2010). We present a new optical-near IR spectrum obtained with ALFOSC-NOT with a new, custom designed dispersive grating aimed to detect broad emission lines that could disprove this classification. In the obtained spectra we do not detect any emission features and we provide an upper limit to the luminosity of the C IV broad emission line. Therefore, the nature of the object is then discussed, building the overall spectral energy distribution and fitting it with three different models. Our fits, based on the SED modeling with different possible scenarios, cannot rule out the possibility that this source is indeed a BL Lac object although, the absence of optical variability and lack of strong radio flux, they seems to suggest that the observed optical emission origi...

  4. OPTICAL SPECTROSCOPY OF SDSS J004054.65-0915268: THREE POSSIBLE SCENARIOS FOR THE CLASSIFICATION. A z ∼ 5 BL LACERTAE, A BLUE FSRQ, OR A WEAK EMISSION LINE QUASAR

    Energy Technology Data Exchange (ETDEWEB)

    Landoni, M.; Zanutta, A.; Bianco, A.; Tavecchio, F.; Bonnoli, G.; Ghisellini, G. [INAF-Osservatorio Astronomico di Brera, Via Emilio Bianchi 46, I-23807 Merate (Italy)

    2016-02-15

    The haunt of high-redshift BL Lacerate objects is day by day more compelling to firmly understand their intrinsic nature and evolution. SDSS J004054.65-0915268 is, at the moment, one of the most distant BL Lac candidates, at z ∼ 5. We present a new optical-near-IR spectrum obtained with ALFOSC-NOT with a new, custom designed dispersive grating aimed to detect broad emission lines that could disprove this classification. In the obtained spectra, we do not detect any emission features and we provide an upper limit to the luminosity of the C iv broad emission line. Therefore, the nature of the object is then discussed, building the overall spectral energy distribution (SED) and fitting it with three different models. Our fits, based on SED modeling with different possible scenarios, cannot rule out the possibility that this source is indeed a BL Lac object, though the absence of optical variability and the lack of strong radio flux seem to suggest that the observed optical emission originates from a thermalized accretion disk.

  5. VLBA Observations of Low Luminosity Flat Spectrum Radio Galaxies and BL Lac Objects: Polarisation Properties

    Science.gov (United States)

    Bondi, M.; Dallacasa, D.; Stanghellini, C.; Marchã, M. J. M.

    We obtained two-epoch VLBA observations at 5 GHz of a list of radio galaxies drawn from the 200 mJy sample (Marcha et al. 1996). The objects selected for milli-arcsecond scale observations are classified, on the basis of their optical spectroscopic and polarimetric properties, as BL Lac objects, normal weak line radio galaxies, broad line radio galaxies, and transition objects (those with intermediate properties). We present preliminary results on the radio polarization properties, on the milli-arcsecond scale, of objects with different optical properties and discuss structural variations detected from the two epochs.

  6. SPECTRAL VARIABILITY AND TRANSIENT INJECTION OF RELATIVISTIC ELECTRONS FOR BL LAC OBJECTS

    Institute of Scientific and Technical Information of China (English)

    MEI DONG-CHENG; XIE GUANG-ZHONG; CHEN LUO-EN

    2000-01-01

    The spectral hardening with increasing intensity in optical range for four BL Lac objects have been found by analyzing our observed data. Making use of the synchrotron loss of transient injection of relativistic electrons, we succeeded in explaining the phenomenon of the spectral hardening in the outburst phase. The value of magnetic intensity and the limit condition of the transient injection of relativistic electrons seem to be reasonable.

  7. Unifying models for X-ray selected and Radio selected BL Lac Objects

    CERN Document Server

    Fossati, G; Ghisellini, G; Maraschi, L; Brera-Merate, O A

    1997-01-01

    We discuss alternative interpretations of the differences in the Spectral Energy Distributions (SEDs) of BL Lacs found in complete Radio or X-ray surveys. A large body of observations in different bands suggests that the SEDs of BL Lac objects appearing in X-ray surveys differ from those appearing in radio surveys mainly in having a (synchrotron) spectral cut-off (or break) at much higher frequency. In order to explain the different properties of radio and X-ray selected BL Lacs Giommi and Padovani proposed a model based on a common radio luminosity function. At each radio luminosity, objects with high frequency spectral cut-offs are assumed to be a minority. Nevertheless they dominate the X-ray selected population due to the larger X-ray-to-radio-flux ratio. An alternative model explored here (reminiscent of the orientation models previously proposed) is that the X-ray luminosity function is "primary" and that at each X-ray luminosity a minority of objects has larger radio-to-X-ray flux ratio. The prediction...

  8. Structured Jets in BL Lac Objects: Efficient PeV Neutrino Factories?

    Science.gov (United States)

    Tavecchio, Fabrizio; Ghisellini, Gabriele; Guetta, Dafne

    2014-09-01

    The origin of high-energy neutrinos (0.1-1 PeV range) detected by IceCube remains a mystery. In this work, we explore the possibility that efficient neutrino production can occur in structured jets of BL Lac objects, characterized by a fast inner spine surrounded by a slower layer. This scenario has been widely discussed in the framework of the high-energy emission models for BL Lac objects and radio galaxies. One of the relevant consequences of a velocity structure is the enhancement of the inverse Compton emission caused by the radiative coupling of the two zones. We show that a similar boosting could occur for the neutrino output of the spine through the photo-meson reaction of high-energy protons scattering off the amplified soft target photon field of the layer. Assuming the local density and the cosmological evolution of γ-ray BL Lac object derived from Fermi Large Area Telescope data, we calculate the expected diffuse neutrino intensity, which can match the IceCube data for a reasonable choice of parameters.

  9. STRUCTURED JETS IN BL LAC OBJECTS: EFFICIENT PeV NEUTRINO FACTORIES?

    Energy Technology Data Exchange (ETDEWEB)

    Tavecchio, Fabrizio; Ghisellini, Gabriele [INAF-Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Italy); Guetta, Dafne [INAF-Osservatorio astronomico di Roma, via Frascati 33, I-00040 Monte Porzio Catone (Italy)

    2014-09-20

    The origin of high-energy neutrinos (0.1–1 PeV range) detected by IceCube remains a mystery. In this work, we explore the possibility that efficient neutrino production can occur in structured jets of BL Lac objects, characterized by a fast inner spine surrounded by a slower layer. This scenario has been widely discussed in the framework of the high-energy emission models for BL Lac objects and radio galaxies. One of the relevant consequences of a velocity structure is the enhancement of the inverse Compton emission caused by the radiative coupling of the two zones. We show that a similar boosting could occur for the neutrino output of the spine through the photo-meson reaction of high-energy protons scattering off the amplified soft target photon field of the layer. Assuming the local density and the cosmological evolution of γ-ray BL Lac object derived from Fermi Large Area Telescope data, we calculate the expected diffuse neutrino intensity, which can match the IceCube data for a reasonable choice of parameters.

  10. Structured jets in BL Lac objects: efficient PeV neutrino factories?

    CERN Document Server

    Tavecchio, F; Guetta, D

    2014-01-01

    The origin of the high-energy neutrinos (0.1$-$1 PeV range) detected by IceCube remains a mystery. In this work we explore the possibility that efficient neutrino production can occur in structured jets of BL Lac objects, characterized by a fast inner spine surrounded by a slower layer. This scenario has been widely discussed in the framework of the high-energy emission models for BL Lacs and radiogalaxies. One of the relevant consequences of a velocity structure is the enhancement of the inverse Compton emission caused by the radiative coupling of the two zones. We show that a similar boosting could occur for the neutrino output of the spine through the photo-meson reaction of high-energy protons scattering off the amplified soft target photon field of the layer. Assuming the local density and the cosmological evolution of $\\gamma$-ray BL Lac derived from {\\it Fermi}-LAT data, we calculate the expected diffuse neutrino intensity, that can match the IceCube data for a reasonable choice of the parameters.

  11. VSOP monitoring of the compact BL Lac object AO 0235+164

    CERN Document Server

    Frey, S; Gabuzda, D C; Salter, C J; Altschüler, D R; Perillat, P; Aller, M F; Aller, H D; Hirabayashi, H; Davis, M M

    2005-01-01

    In 1999, the highly compact and variable BL Lac object AO 0235+164 was identified as the highest brightness temperature active galactic nucleus observed with the VLBI Space Observatory Programme (VSOP), with T_B > 5.8 x 10^{13} K. The sub-milliarcsecond radio structure of this source has been studied with dual-frequency (1.6 and 5 GHz), polarization-sensitive VSOP observations during 2001 and 2002. Here we present the results of this monitoring campaign. At the time of these observations, the source was weakly polarized and characterized by a radio core that is clearly resolved on space-ground baselines.

  12. Modelling the IDV Emissions of the BL Lac Objects with a Langevin Type Stochastic Differential Equation

    Indian Academy of Sciences (India)

    C. S. Leung; J. Y. Wei; T. Harko; Z. Kovacs

    2011-03-01

    In this paper, we introduce a simplified model for explaining the observations of optical intra-day variability (IDV) of the BL Lac Objects. We assume that the source of the IDV are the stochastic oscillations of an accretion disk around a supermassive black hole. The stochastic fluctuations on the vertical direction of the accretion disk are described by using a Langevin type equation with a damping term and a random, white noise type force. Furthermore, preliminary numerical simulation results are presented, which are based on the numerical analysis of the Langevin stochastic differential equation.

  13. Fermi LAT Detection of a Gamma-ray Flare from the BL Lac Object ON 246

    Science.gov (United States)

    Becerra, Josefa

    2015-06-01

    The Large Area Telescope (LAT) on board the Fermi Gamma-ray Space Telescope has observed increasing gamma-ray flux from a source positionally consistent with the BL Lac object ON 246 (RA=187.55871 deg, Dec=25.30198 deg, J2000, Beasley et al. 2002, ApJS, 141, 13; with redshift z=0.135, Nass et al. 1996, A&A, 309, 419), also known as S3 1227+25 and 3FGL J1230.3+2519 (3FGL; Acero et al. 2015, arXiv:1501.02003).

  14. The long-term optical behavior of BL Lac object S5 0716+714

    Institute of Scientific and Technical Information of China (English)

    2010-01-01

    BL Lac object S5 0716+714 is a well-studied object.In this paper,the available optical(BVRI) data of this source are compiled,and the B-,V-,R-and I-band light curves are constructed.Each of them is analyzed by means of the discrete correlation function(DCF) method,the structure function(SF) method and the z-transformed discrete correlation function(ZDCF) method.The results imply that there is a possible periodic variation of 1211 days in each passband light curve.The source varies violently and complicatedly,and exhibits a brightening trend in the light curves.

  15. Optical and Radio variability of the Northern VHE gamma-ray emitting BL Lac objects

    CERN Document Server

    Lindfors, E J; Nilsson, K; Reinthal, R; Ramazani, V Fallah; Pavlidou, V; Max-Moerbeck, W; Richards, J; Berdyugin, A; Takalo, L; Sillanpää, A; Readhead, A C S

    2016-01-01

    We compare the variability properties of very high energy gamma-ray emitting BL Lac objects in the optical and radio bands. We use the variability information to distinguish multiple emission components in the jet, to be used as a guidance for spectral energy distribution modelling. Our sample includes 32 objects in the Northern sky that have data for at least 2 years in both bands. We use optical R-band data from the Tuorla blazar monitoring program and 15 GHz radio data from the Owens Valley Radio Observatory blazer monitoring program. We estimate the variability amplitudes using the intrinsic modulation index, and study the time-domain connection by cross-correlating the optical and radio light curves assuming power law power spectral density. Our sample objects are in general more variable in the optical than radio. We find correlated flares in about half of the objects, and correlated long-term trends in more than 40% of the objects. In these objects we estimate that at least 10%-50% of the optical emiss...

  16. Analysis of Optical Variations of BL Lac Object AO 0235+164

    Indian Academy of Sciences (India)

    Wang Hong-tao

    2014-03-01

    Historical optical BVRI band data are combined on the BL Lac object AO 0235 + 164. In order to examine the possible existence of lags and correlations between variations in different optical bands from this source, a statistical analysis is performed through the Discrete Correlation Function (DCF) method. Monte Carlo simulations called Flux Redistribution/Random Subset Selection (FR/RSS) are performed to obtain statistically meaningful values for the cross-correlation time lags and their related uncertainties. The analysis confirms that the variations in different optical light curves are strongly correlated, with no or very weak lag within the errors. Long term variability of color indices are also analysed. No color variabilities are found.

  17. The physical properties of Fermi TeV BL Lac objects' jets

    Science.gov (United States)

    Ding, N.; Zhang, X.; Xiong, D. R.; Zhang, H. J.

    2017-01-01

    We investigate the physical properties of Fermi TeV BL Lac objects' jets by modelling the quasi-simultaneous spectral energy distribution of 29 Fermi TeV BL Lacs in the frame of a one-zone leptonic synchrotron self-Compton model. Our main results are the following. (i) There is a negative correlation between B and δ in our sample, which suggests that B and δ are dependent on each other mainly in the Thomson regime. (ii) There are negative correlations between νsy and r, the νIC and r, which is a signature of the energy-dependent statistical acceleration or the stochastic acceleration. There is a significant correlation between r and s, which suggests that the curvature of the electron energy distribution is attributed to the energy-dependent statistical acceleration mechanism. (iii) By assuming one proton per relativistic electron, we estimate the jet power and radiative power. A size relation Pe ˜ Pp > Pr ≳ PB is found in our sample. The Pe > PB suggests that the jets are particle dominated, and the Pe ˜ Pp means that the mean energy of relativistic electrons approaches mp/me. There are not significant correlations between Pjet and black hole mass in high or low state with a subsample of 18 sources, which suggests that the jet power weakly depends on the black hole mass. (iv) There is a correlation between the changes in the flux density at 1 TeV and the changes in the γpeak, which suggests that the change/evolution of electron energy distribution may be mainly responsible for the flux variation.

  18. VERITAS Observations of the BL Lac Object PG 1553+113

    CERN Document Server

    Aliu, E; Aune, T; Barnacka, A; Behera, B; Beilicke, M; Benbow, W; Berger, K; Bird, R; Buckley, J H; Bugaev, V; Byrum, K; Cardenzana, J V; Cerruti, M; Chen, X; Ciupik, L; Connolly, M P; Cui, W; Dickinson, H J; Dumm, J; Eisch, J D; Errando, M; Falcone, A; Federici, S; Feng, Q; Finley, J P; Fortin, P; Fortson, L; Furniss, A; Galante, N; Gillanders, G H; Griffin, S; Griffiths, S T; Grube, J; Gyuk, G; Håkansson, N; Hanna, D; Holder, J; Hughes, G; Humensky, T B; Johnson, C A; Kaaret, P; Kertzman, P Kar M; Khassen, Y; Kieda, D; Krawczynski, H; Krennrich, F; Kumar, S; Lang, M J; Madhavan, A; McArthur, S; McCann, A; Meagher, K; Millis, J; Moriarty, P; Nieto, D; de Bhróithe, A O'Faoláin; Ong, R A; Orr, M; Otte, A N; Park, N; Perkins, J S; Pohl, M; Popkow, A; Prokoph, H; Pueschel, E; Quinn, J; Ragan, K; Rajotte, J; Reyes, L C; Reynolds, P T; Richards, G T; Roache, E; Sembroski, G H; Shahinyan, K; Staszak, D; Telezhinsky, I; Tucci, J V; Tyler, J; Varlotta, A; Vassiliev, V V; Wakely, S P; Weinstein, A; Welsing, R; Wilhelm, A; Williams, D A; Zitzer, B

    2014-01-01

    We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560\\,GeV, is well described by a power law with a spectral index of $4.33 \\pm 0.09$. The time-averaged integral flux above $200\\,$GeV measured for this period was $(1.69 \\pm 0.06) \\times 10^{-11} \\, \\mathrm{ph} \\, \\mathrm{cm}^{-2} \\, \\mathrm{s}^{-1}$, corresponding to 6.9\\% of the Crab Nebula flux. We also present the combined $\\gamma$-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100~MeV to 560~GeV. The data are well fit by a power law with an exponential cutoff at $\\rm {101.9 \\pm 3.2 \\, \\mathrm{GeV}} $. The origin of the cutoff could be intrinsic to PG~1553+113 or be due to the $\\gamma$-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of $\\rm z \

  19. BL LAC OBJECT PKS B1144-379: AN EXTREME SCINTILLATOR

    Energy Technology Data Exchange (ETDEWEB)

    Turner, R. J.; Ellingsen, S. P.; Shabala, S. S.; Blanchard, J.; Lovell, J. E. J.; McCallum, J. N. [School of Mathematics and Physics, Private Bag 37, University of Tasmania, Hobart, TAS 7001 (Australia); Cimo, G. [Joint Institute for VLBI in Europe, Postbus 2, 7990 AA Dwingeloo (Netherlands)

    2012-08-01

    Rapid variability in the radio flux density of the BL Lac object PKS B1144-379 has been observed at four frequencies, ranging from 1.5 to 15 GHz, with the Very Large Array and the University of Tasmania's Ceduna antenna. Intrinsic and line-of-sight effects were examined as possible causes of this variability, with interstellar scintillation best explaining the frequency dependence of the variability timescales and modulation indices. This scintillation is consistent with a compact source 20-40 {mu}as or 0.15-0.3 pc in size. The inferred brightness temperature for PKS B1144-379 (assuming that the observed variations are due to scintillation) is 6.2 Multiplication-Sign 10{sup 12} K at 4.9 GHz, with approximately 10% of the total flux in the scintillating component. We show that scintillation surveys aimed at identifying variability timescales of days to weeks are an effective way to identify the active galactic nuclei with the highest brightness temperatures.

  20. Discovery of VHE gamma-rays from the BL Lac object PKS 0548-322

    CERN Document Server

    Akhperjanian, A G; de Almeida, U Barres; Bazer-Bachi, A R; Becherini, Y; Behera, B; Benbow, W; Bernlöhr, K; Bochow, A; Boisson, C; Bolmont, J; Borrel, V; Brucker, J; Brun, F; Brun, P; Bühler, R; Bulik, T; Büsching, I; Boutelier, T; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L -M; Clapson, A C; Coignet, G; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dyks, J; Dyrda, M; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Füssling, M; Gabici, S; Gallant, Y A; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Hauser, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; deJager, O C; Jahn, C; Jung, I; Katarzyński, K; Katz, U; Kaufmann, S; Kendziorra, E; Kerschhagg, M; Khangulyan, D; Khélifi, B; Keogh, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Lamanna, G; Lenain, J -P; Lohse, T; Marandon, V; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masbou, J; Maurin, D; McComb, T J L; Medina, M C; Moderski, R; Moulin, E; Naumann-Godo, M; deNaurois, M; Nedbal, D; Nekrassov, D; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Olive, J-F; Wilhelm, E de Oña; Orford, K J; Ostrowski, M; Panter, M; Arribas, M Paz; Pedaletti, G; Pelletier, G; Petrucci, P -O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Santangelo, A; Schlickeiser, R; Schöck, F M; Schröder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sikora, M; Skilton, J L; Sol, H; Spangler, D; Stawarz, L; Steenkamp, R; Stegmann, C; Stinzing, F; Superina, G; Szostek, A; Tam, P H; Tavernet, J -P; Terrier, R; Tibolla, O; Tluczykont, M; vanEldik, C; Vasileiadis, G; Venter, C; Venter, L; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volp, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2010-01-01

    PKS 0548-322 (z=0.069) is a ``high-frequency-peaked'' BL Lac object and a candidate very high energy (VHE, E>100 GeV) gamma-ray emitter, due to its high X-ray and radio flux. Observations at the VHE band provide insights into the origin of very energetic particles present in this source and the radiation processes at work. We report observations made between October 2004 and January 2008 with the H.E.S.S. array, a four imaging atmospheric-Cherenkov telescopes. Contemporaneous UV and X-ray observations with the Swift satellite in November 2006 are also reported. PKS 0548-322 is detected for the first time in the VHE band with H.E.S.S. We measure an excess of 216 gamma-rays corresponding to a significance of 5.6 standard deviations. The photon spectrum of the source is described by a power-law, with a photon index of Gamma=2.86 +/- 0.34 (stat) +/- 0.10 (sys). The integral flux above 200 GeV is 1.3 % of the flux of the Crab Nebula, and is consistent with being constant in time. Contemporaneous Swift/XRT observat...

  1. Contemporaneous broadband observations of three high-redshift BL Lac Objects

    CERN Document Server

    ,

    2016-01-01

    We have collected broadband spectral energy distributions (SEDs) of three BL Lac objects, 3FGL J0022.1$-$1855 (z=0.689), 3FGL J0630.9$-$2406 (z >~ 1.239), and 3FGL J0811.2$-$7529 (z=0.774), detected by Fermi with relatively flat GeV spectra. By observing simultaneously in the near-IR to hard X-ray band, we can well characterize the high end of the synchrotron component of the SED. Thus, fitting the SEDs to synchro-Compton models of the dominant emission from the relativistic jet, we can constrain the underlying particle properties and predict the shape of the GeV Compton component. Standard extragalactic background light (EBL) models explain the high-energy absorption well, with poorer fits for high UV models. The fits show clear evidence for EBL absorption in the Fermi spectrum of our highest redshift source 3FGL J0630.9$-$2406. While synchrotron self-Compton models adequately describe the SEDs, the situation may be complicated by possible external Compton components. For 3FGL J0811.2$-$7529, we also discove...

  2. Multiwavelength Observations of 6 BL Lac Objects in 2008-2012

    Directory of Open Access Journals (Sweden)

    Morozova D.A.

    2013-12-01

    Full Text Available We present results of 4 years of VLBA monitoring along with γ-ray and optical R-band photometric observations of 6 BL Lac objects (3C 66A, S5 0716+71, PKS 0735+17, S4 0954+68, W Com, and OT 081. We have analyzed total intensity images obtained with the VLBA at 43 GHz and investigated the kinematic evolution of the parsec scale jets of the sources. For all sources we compare flux variations in the VLBI core and bright superluminal knots with γ-ray and optical light curves. The majority of γ-ray flares have optical counterparts. 67% of the γ-ray events are coincident with the appearance of new superluminal knots and/or flares in the millimeter-wave core. These results support the conclusion that for many flares in blazars the region of the γ-ray and optical emission is located in the vicinity or downstream of the mm-wave VLBI core.

  3. BeppoSAX Observations of Unprecedented Synchrotron Activity in the BL Lac Object Mkn 501

    CERN Document Server

    Pian, E; Tagliaferri, G; Ghisellini, G; Maraschi, L; Treves, A; Urry, C M; Fiore, F; Giommi, P; Palazzi, E; Chiappetti, L; Sambruna, R M; Pian, Elena; Vacanti, Giuseppe; Tagliaferri, Gianpiero; Ghisellini, Gabriele; Maraschi, Laura; Treves, Aldo; Fiore, Fabrizio; Giommi, Paolo; Palazzi, Eliana; Chiappetti, Lucio; Sambruna, Rita M.

    1997-01-01

    The BL Lac object Mkn 501, one of the only three extragalactic sources (with Mkn 421 and 1ES 2344+514) so far detected at TeV energies, was observed with the BeppoSAX satellite on 7, 11, and 16 April 1997 during a phase of high activity at TeV energies, as monitored with the Whipple, HEGRA and CAT Cherenkov telescopes. Over the whole 0.1-200 keV range the spectrum was exceptionally hard (alpha =< 1, with F_nu ~ nu^{-alpha}) indicating that the X-ray power output peaked at (or above) ~100 keV. This represents a shift of at least two orders of magnitude with respect to previous observations of Mkn 501, a behavior never seen before in this or any other blazar. The overall X-ray spectrum hardens with increasing intensity and, at each epoch, it is softer at larger energies. The correlated variability from soft X-rays to the TeV band points to models in which the same population of relativistic electrons produces the X-ray continuum via synchrotron radiation and the TeV emission by inverse Compton scattering of ...

  4. VERITAS OBSERVATIONS OF THE BL LAC OBJECT PG 1553+113

    Energy Technology Data Exchange (ETDEWEB)

    Aliu, E. [Department of Physics and Astronomy, Barnard College, Columbia University, NY 10027 (United States); Archer, A.; Beilicke, M.; Buckley, J. H.; Bugaev, V. [Department of Physics, Washington University, St. Louis, MO 63130 (United States); Aune, T. [Department of Physics and Astronomy, University of California, Los Angeles, CA 90095 (United States); Barnacka, A. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Behera, B.; Chen, X. [DESY, Platanenallee 6, 15738 Zeuthen (Germany); Benbow, W.; Cerruti, M. [Fred Lawrence Whipple Observatory, Harvard-Smithsonian Center for Astrophysics, Amado, AZ 85645 (United States); Berger, K. [Department of Physics and Astronomy and the Bartol Research Institute, University of Delaware, Newark, DE 19716 (United States); Bird, R. [School of Physics, University College Dublin, Belfield, Dublin 4 (Ireland); Byrum, K. [Argonne National Laboratory, 9700 South Cass Avenue, Argonne, IL 60439 (United States); Cardenzana, J. V; Dickinson, H. J. [Department of Physics and Astronomy, Iowa State University, Ames, IA 50011 (United States); Ciupik, L. [Astronomy Department, Adler Planetarium and Astronomy Museum, Chicago, IL 60605 (United States); Connolly, M. P. [School of Physics, National University of Ireland Galway, University Road, Galway (Ireland); Cui, W. [Department of Physics and Astronomy, Purdue University, West Lafayette, IN 47907 (United States); Dumm, J. [School of Physics and Astronomy, University of Minnesota, Minneapolis, MN 55455 (United States); and others

    2015-01-20

    We present results from VERITAS observations of the BL Lac object PG 1553+113 spanning the years 2010, 2011, and 2012. The time-averaged spectrum, measured between 160 and 560 GeV, is well described by a power law with a spectral index of 4.33 ± 0.09. The time-averaged integral flux above 200 GeV measured for this period was (1.69 ± 0.06) × 10{sup –11} photons cm{sup –2} s{sup –1}, corresponding to 6.9% of the Crab Nebula flux. We also present the combined γ-ray spectrum from the Fermi Large Area Telescope and VERITAS covering an energy range from 100 MeV to 560 GeV. The data are well fit by a power law with an exponential cutoff at 101.9 ± 3.2 GeV. The origin of the cutoff could be intrinsic to PG 1553+113 or be due to the γ-ray opacity of our universe through pair production off the extragalactic background light (EBL). Given lower limits to the redshift of z > 0.395 based on optical/UV observations of PG 1553+113, the cutoff would be dominated by EBL absorption. Conversely, the small statistical uncertainties of the VERITAS energy spectrum have allowed us to provide a robust upper limit on the redshift of PG 1553+113 of z ≤ 0.62. A strongly elevated mean flux of (2.50 ± 0.14) × 10{sup –11} photons cm{sup –2} s{sup –1} (10.3% of the Crab Nebula flux) was observed during 2012, with the daily flux reaching as high as (4.44±0.71)×10{sup −11} photons cm{sup −2} s{sup −1} (18.3% of the Crab Nebula flux) on MJD 56048. The light curve measured during the 2012 observing season is marginally inconsistent with a steady flux, giving a χ{sup 2} probability for a steady flux of 0.03%.

  5. Fermi LAT detection of a GeV gamma-ray flare from the BL Lac object AP Librae

    Science.gov (United States)

    Ciprini, Stefano

    2016-08-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with the BL Lac object AP Lib (also known as PKS 1514-24 and 3FGL J1517.6-2422), with radio counterpart position R.A.: 229.424221 deg, Dec.: -24.372076 deg, (J2000.0, Johnston et al. 1995, AJ, 110, 880).

  6. The Luminosity Function of the Host Galaxies of QSOs and BL Lac Objects

    CERN Document Server

    Carangelo, N; Treves, A

    2001-01-01

    A clear insight of the galaxies hosting active galactic nuclei is of fundamental importance for understanding the processes of galaxies and nuclei formation and their cosmic evolution. A good characterization of the host galaxies properties requires images of excellent quality in order to disentangle the light of the galaxy from that of the bright nucleus. To this aim HST has provided a major improvement of data on QSOs (Disney et al. 1995; Bahcall et al. 1996, 1997; Boyce et al. 1998; McLure et al. 1999; Hamilton et al. 2000; Kukula et al. 2001) and BL Lacs (Scarpa et al. 2000, Urry et al. 2000). We present a comparative study of low redshift QSO and BL Lac host galaxy luminosity function (HGLF). To this aim we have considered samples of BL Lacs (Urry et al. 2000) and QSOs (Bahcall et al. 1997; Boyce et al. 1998; McLure et al. 1999) that have been well resolved by images obtained with WFPC2 on board of HST.

  7. Computing Optical Variable Periods of BL Lac Object S5 0716+714 with Period04 Analysis Method

    Indian Academy of Sciences (India)

    Junping Fu; Xiong Zhang; Dingrong Xiong

    2014-09-01

    From a large volume of literature, we have collected effective observation of BL Lac object S5 0716+714 in the optical band, and constructed its long-term light curve from 1994 to 2006 AD. The light curve shows that S5 0716+714 is very active and exhibits very complicated non-sinusoidal variations. We used Period04 to analyse the period of light curve variation. Our results show that for S5 0716+714, the long-term period of variation is 3.3 yr which is consistent with the result of Raiter et al. (2003).

  8. An Analysis of Light Periods of BL Lac Object S5 0716+714 with the MUSIC Algorithm

    Science.gov (United States)

    Tang, Jie

    2012-07-01

    The multiple signal classification (MUSIC) algorithm is introduced to the estimation of light periods of BL Lac objects. The principle of the MUSIC algorithm is given, together with a testing on its spectral resolution by using a simulative signal. From a lot of literature, we have collected a large number of effective observational data of the BL Lac object S5 0716+714 in the three optical wavebands V, R, and I from 1994 to 2008. The light periods of S5 0716+714 are obtained by means of the MUSIC algorithm and average periodogram algorithm, respectively. It is found that there exist two major periodic components, one is the period of (3.33±0.08) yr, another is the period of (1.24±0.01) yr. The comparison of the performances of periodicity analysis of two algorithms indicates that the MUSIC algorithm has a smaller requirement on the sample length, as well as a good spectral resolution and anti-noise ability, to improve the accuracy of periodicity analysis in the case of short sample length.

  9. Discovery of a variable broad absorption line in the BL Lac object PKS B0138-097

    Institute of Scientific and Technical Information of China (English)

    Shao-Hua Zhang; Hui-Yuan Wang; Hong-Yan Zhou; Ting-Gui Wang; Peng Jiang

    2011-01-01

    We report the discovery of a broad absorption line (BAL) of ~104 km s-1in width in the previously known BL Lac object PKS 0138-097,which we tentatively identified as an Mg Ⅱ BAL.This is the first detection of a BAL,which is sometimes seen in powerful quasars with high accretion rates,in a BL Lac object.The BAL was clearly detected in its spectra spanning two epochs at a high luminosity state taken in the Sloan Digital Sky Survey (SDSS),while it disappeared in three SDSS spectra taken at a low luminosity state.The BAL and its variability pattern were also found in its historical multi-epoch spectra in the literature,but have been overlooked previously.In its high resolution radio maps,PKS 0138-097 shows a core plus a onesided parsec-scale jet.The BAL variability can be interpreted as follows:The optical emission is dominated by the core in a high state and by the jet in a low state and the BAL material is located between the core and jet so that the BAL appears only when the core is shining.Our discovery suggests that outflows may also be produced in active galactic nuclei at a low accreting state.

  10. Connection between inner jet kinematics and broadband flux variability in the BL Lac object S5 0716+714

    CERN Document Server

    Rani, B; Marscher, A P; Hodgson, J A; Fuhrmann, L; Angelakis, E; Britzen, S; Zensus, J A

    2015-01-01

    We present a high-frequency very long baseline interferometry (VLBI) kinematical study of the BL Lac object S5 0716+714 over the time period of September 2008 to October 2010. The aim of the study is to investigate the relation of the jet kinematics to the observed broadband flux variability. We find significant non-radial motions in the jet outflow of the source. In the radial direction, the highest measured apparent speed is \\sim37 c, which is exceptionally high, especially for a BL Lac object. Patterns in the jet flow reveal a roughly stationary feature \\sim0.15 mas downstream of the core. The long-term fits to the component trajectories reveal acceleration in the sub-mas region of the jet. The measured brightness temperature, T_{B}, follows a continuous trend of decline with distance, T_B \\propto r_{jet}^{-(2.36\\pm0.41)}, which suggests a gradient in Doppler factor along the jet axis. Our analysis suggest that a moving disturbance (or a shock wave) from the base of the jet produces the high-energy (optica...

  11. Systematic search for VHE gamma-ray emission from X-ray bright high-frequency BL Lac objects

    CERN Document Server

    Albert, J

    2007-01-01

    Motivated by the fact that all but two (M87, BL Lac) extragalactic sources detected so far at VHE energies belong to the so-called HBL class of high-frequency peaked BL Lac objects, a systematic scan of the compilation of X-ray blazars by Donato et al. (2001) has been performed using the MAGIC telescope. The observations took place from December 2004 to March 2006 and cover sources on the northern sky visible under small zenith distances zd 2uJy) sources emitting at least the same energy flux at 200GeV as at 1keV. In order to avoid strong gamma-ray attenuation close to the energy threshold, the redshift of the sources was constrained to values z < 0.3. Of the 14 sources observed, 1ES 1218+30.4 (for the first time at very high energies) and 1ES 2344+51.4 (strong detection in a low flux state) have been detected in addition to the known bright TeV blazars Mrk 421 and Mrk 501. For the remaining sources, we present here the 99% confidence level upper limits on the integral flux above ~200GeV. A marginal exces...

  12. The Hybrid Nature of 0846+51W1: a BL Lac Object with a Narrow Line Seyfert 1 Nucleus

    Institute of Scientific and Technical Information of China (English)

    Hong-Yan Zhou; Ting-Gui Wang; Xiao-Bo Dong; Cheng Li; Xue-Guang Zhang

    2005-01-01

    We found a NLS1 nucleus in the extensively studied eruptive BL Lac object, 0846+51W1, out of a large sample of NLS1s compiled from the spectroscopic dataset of SDSS DR1. Its optical spectrum can be well decomposed into three components: a power law component from the relativistic jet, a stellar component from the host galaxy, and a component from a typical NLS1 nucleus. The emission line properties of 0846+51Wl, FWHM (Hβ)∽- 1710 km s-1 and [OⅢ]λ5007 /Hβ∽-0.32from its SDSS spectrum observed when it was in the faint state, fulfil the conventional definition of NLS1. Strong FelI emission is detected in the SDSS spectrum,which is also typical of NLS1s. We tried to estimate its central black hole mass using various techniques and found that 0846+51W1 is very likely emitting at a few × 10% of the Eddington luminosity. We speculate that Seyfert-like nuclei, including NLS1s, might be concealed in a significant fraction of BL Lacs but have remained largely unobserved because, often, their optical-UV continuum is overwhelmed by the synchrotron emission.

  13. VERITAS long-term (2006-2014) observations of the BL Lac object 1ES 0806+524

    CERN Document Server

    Cerruti, Matteo

    2015-01-01

    The discovery of the high-frequency-peaked BL Lac object 1ES 0806+524 (z=0.138) as a source of very-high-energy (VHE, E>100 GeV) gamma-ray photons was announced in 2008 by the VERITAS Collaboration, at a level of 1.8% of the Crab Nebula flux above 300 GeV. Since then, VERITAS has continued observing the source over multiple seasons, significantly improving the significance of the detection. We report the results of the analysis of the 2006-2014 VERITAS data, corresponding to a total exposure of about 70 hours. We present the new, average VHE spectrum of the source, together with the multi-year light-curve constraining long-term VHE variability.

  14. Chaotic Behaviour of Intra-Day Variability of BL Lac Object S5 0716+714

    Indian Academy of Sciences (India)

    Shuhong Li; Jianwen Ou; Zheng Liu

    2014-06-01

    An optical monitoring shows Blazar object S5 0716+714 has complex Intra-Day Variability (IDV) behaviour. In this paper, we introduce a method of non-linear time series analysis, and calculate the correlation dimension of the IDV light curves of S5 0716+714 over seven nights in the December of 2006. According to our calculations, the correlation dimension ≈ 1.993-5.178 for all of the observed data, it is implied that the IDV behaviour may be a chaotic system with some additional noise.

  15. The Sedentary Survey of Extreme High Energy Peaked BL Lacs III. Results from Optical Spectroscopy

    CERN Document Server

    Piranomonte, S; Giommi, P; Landt, H; Padovani, P

    2007-01-01

    The multi-frequency Sedentary Survey is a flux limited, statistically well-defined sample of highly X-ray dominated BL Lacertae objects (HBLs) which includes 150 sources. In this paper, the third of the series, we report the results of a dedicated optical spectroscopy campaign that, together with results from other independent optical follow up programs, led to the spectroscopic identification of all sources in the sample. We carried out a systematic spectroscopic campaign for the observation of all unidentified objects of the sample using the ESO 3.6m, the KPNO 4m, and the TNG optical telescopes. We present new identifications and optical spectra for 76 sources, 50 of which are new BL Lac objects, 18 are sources previously referred as BL Lacs but for which no redshift information was available, and 8 are broad emission lines AGNs. We find that the multi-frequency selection technique used to build the survey is highly efficient (about 90%) in selecting BL Lacs objects. We present positional and spectroscopic ...

  16. HST/COS Observations of the Ly alpha Forest toward the BL Lac Object 1ES1553+113

    CERN Document Server

    Danforth, Charles W; Stocke, John T; Shull, J Michael; Yao, Yangsen

    2010-01-01

    We present new far-ultraviolet spectra from the Cosmic Origins Spectrograph (HST/COS) of the BL Lac object 1ES1553+113 covering the wavelength range 1135-1795 A. The data show a smooth continuum with a wealth of narrow absorption features arising in the ISM and IGM. These features include 41 Lya absorbers at 00.6 for the strongest component of the absorber complex. Galaxy redshift surveys show a number of massive galaxies at approximately the same redshift as this absorption complex, suggesting that it arises in a large-scale galaxy filament. As one of the brightest extragalactic X-ray and gamma-ray sources, 1ES1553+113 is of great interest to the high-energy astrophysics community. With no intrinsic emission or absorption features, 1ES1553+113 has no direct redshift determination. We use intervening Lya absorbers to place a direct limit on the redshift: z_em>0.395 based on a confirmed Lya+OVI absorber and z_em>0.433 based on a single-line detection of Lya. COS/FUV data are only sensitive to Lya absorbers at ...

  17. Quasi-simultaneous observations of BL Lac object Mrk 501 in X-ray, UV, visible, IR, and radio frequencies

    Science.gov (United States)

    Kondo, Y.; Worrall, D. M.; Oke, J. B.; Yee, H. K. C.; Neugebauer, G.; Matthews, K.; Feldman, P. A.; Mushotzky, R. F.; Hackney, R. L.; Hackney, K. R. H.

    1981-01-01

    Observations in the X-ray, UV, visible, IR and radio regions of the BL Lac object Mrk 501 made over the course of two months are reported. The measurements were made with the A2 experiment on HEAO 1 (X-ray), the SWP and LWR cameras on IUE (UV), the 5-m Hale telescope (visible), the 2.5-m telescope at Mount Wilson (IR), the NRAO 92-m radio telescope at Green Bank (4750 MHz) and the 46-m radio telescope at the Algonquin Observatory (10275 and 10650 MHz). The quasi-simultaneously observed spectral slope is found to be positive and continuous from the X-ray to the UV, but to gradually flatten and possibly turn down from the mid-UV to the visible; the optical-radio emission cannot be accounted for by a single power law. The total spectrum is shown to be compatible with a synchrotron self-Compton emission mechanism, while the spectrum from the visible to the X-ray is consistent with synchrotron radiation or inverse-Compton scattering by a hot thermal electron cloud. The continuity of the spectrum from the UV to the X-ray is noted to imply a total luminosity greater than previous estimates by a factor of 3-4.

  18. Discovery of hard-spectrum \\gamma-ray emission from the BL Lac object 1ES 0414+009

    CERN Document Server

    Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Balzer, A; Barnacka, A; de Almeida, U Barres; Becherini, Y; Becker, J; Behera, B; Bernlöhr, K; Birsin, E; Biteau, J; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Büsching, I; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Chounet, L -M; Clapson, A C; Coignet, G; Cologna, G; Conrad, J; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubois, F; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Farnier, C; Feinstein, F; Fernandes, M V; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gallant, Y A; Gast, H; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Göring, D; Häffner, S; Hague, J D; Hampf, D; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzynski, K; Katz, U; Kaufmann, S; Keogh, D; Khangulyan, D; Khélifi, B; Kluźniak, D Klochkov W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Laffon, H; Lamanna, G; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maurin, D; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nguyen, N; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Wilhelmi, E de Ona; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Arribas, M Paz; Pedaletti, G; Pelletier, G; Petrucci, P -O; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Rayner, S M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Ruppel, J; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schöck, F M; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sheidaei, F; Sikora, M; Skilton, J L; Sol, H; Spengler, G; Stawarz, L; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; White, R; Wierzcholska, A; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S; Costamante, L; Fegan, S; Ajello, M

    2012-01-01

    1ES 0414+009 (z = 0.287) is a distant high-frequency-peaked BL Lac object, and has long been considered a likely emitter of very-high energy (VHE, E>100 GeV) gamma-rays due to its high X-ray and radio flux. Observations in the VHE gamma-ray band and across the electromagnetic spectrum can provide insights into the origin of highly energetic particles present in the source and the radiation processes at work. Because of the distance of the source, the gamma-ray spectrum might provide further limits on the level of the Extragalactic Background Light (EBL). We report observations made between October 2005 and December 2009 with H.E.S.S., an array of four imaging atmospheric Cherenkov telescopes. Observations at high energies (HE, 100 MeV - 100 GeV) with the Fermi-LAT instrument in the first 20 months of its operation are also reported. To complete the multi-wavelength picture, archival UV and X-ray observations with the Swift satellite and optical observations with the ATOM telescope are also used. Based on the ...

  19. Multi-wavelength study of flaring activity in BL Lac object S5 0716+714 during 2015 outburst

    CERN Document Server

    Chandra, Sunil; Kushwaha, Pankaj; Singh, K P; Bottcher, M; Kaur, Navpreet; Baliyan, K S

    2015-01-01

    We present a detailed investigation of the flaring activity observed from a BL Lac object, S5 0716+714 , during its brightest ever optical state in the second half of January 2015. Observed almost simultaneously in the optical, X-rays and {\\gamma}-rays, a significant change in the degree of optical polarization (PD) and a swing in the position angle (PA) of polarization were recorded. A detection in the TeV (VHE) was also reported by the MAGIC consortium during this flaring episode. Two prominent sub-flares, peaking about 5-days apart, were seen in almost all the energy bands. The multi-wavelength light-curves, spectral energy distribution (SED) and polarization are modeled using the time-dependent code developed by Zhang et al. (2014). This model assumes a straight jet threaded by large scale helical magnetic fields taking into account the light travel time effects, incorporating synchrotron flux and polarization in 3D geometry. The rapid variation in PD and rotation in PA are most likely due to re-connectio...

  20. Discovery of high and very high-energy emission from the BL Lac object SHBL J001355.9-185406

    CERN Document Server

    :,; Acero, F; Aharonian, F; Akhperjanian, A G; Angüner, E; Anton, G; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Tjus, J Becker; Bernlöhr, K; Birsin, E; Bissaldi, E; Biteau, J; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Chalme-Calvet, R; Chaves, R C G; Cheesebrough, A; Chrétien, M; Colafrancesco, S; Cologna, G; Conrad, J; Couturier, C; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; deWilt, P; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Edwards, T; Egberts, K; Eger, P; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gajdus, M; Gallant, Y A; Garrigoux, T; Gast, H; Giebels, B; Glicenstein, J F; Göring, D; Grondin, M -H; Grudzińska, M; Häffner, S; Hague, J D; Hahn, J; Harris, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; Jahn, C; Jamrozy, M; Janiak, M; Jankowsky, F; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Khélifi, B; Kieffer, M; Klepser, S; Klochkov, D; Kluźniak, W; Kneiske, T; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lefaucheur, J; Lemoine-Goumard, M; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Menzler, U; Meyer, M; Moderski, R; Mohamed, M; Moulin, E; Murach, T; Naumann, C L; de Naurois, M; Nedbal, D; Niemiec, J; Nolan, S J; Oakes, L; Ohm, S; Wilhelmi, E de O\; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Raue, M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spengler, G; Spieß, F; Stawarz, {Ł }; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Trichard, C; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorster, M; Wagner, S J; Wagner, P; Ward, M; Weidinger, M; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S

    2013-01-01

    The detection of the high-frequency peaked BL Lac object (HBL) SHBL J001355.9-185406 ($z$=0.095) at high (HE; 100 MeV$100\\,{\\rm GeV}$) with the \\fer\\ Large Area Telescope (LAT) and the High Energy Stereoscopic System (H.E.S.S.) is reported. Dedicated observations have been performed with the H.E.S.S. telescopes, leading to a detection at the $5.5\\,\\sigma$ significance level. The measured flux above 310 GeV is $(8.3 \\pm 1.7_{\\rm{stat}}\\pm 1.7_{\\rm{sys}})\\times 10^{-13}$ photons \\cms\\ (about 0.6% of that of the Crab Nebula), and the power law spectrum has a photon index of \\indexHESS. Using 3.5 years of publicly available \\fla\\ data, a faint counterpart has been detected in the LAT data at the $5.5\\,\\sigma$ significance level, with an integrated flux above 300 MeV of $(9.3 \\pm 3.4_{\\rm stat} \\pm 0.8_{\\rm sys})\\times 10^{-10}$ photons \\cms\\ and a photon index of $\\Gamma = 1.96 \\pm 0.20_{\\rm stat} \\pm 0.08_{\\rm sys}$. X-ray observations with \\textit{Swift}-XRT allow the synchrotron peak energy in $\

  1. Correlation between the TeV and X-ray emission in high--energy peaked BL Lac objects

    CERN Document Server

    Katarzynski, K; Tavecchio, F; Maraschi, L; Fossati, G; Mastichiadis, A

    2004-01-01

    We discuss the correlation between the evolution of the TeV emission and X-ray radiation observed in high-energy peaked BL Lac objects. We describe such a correlation by a simple power law. In the first part of this work we present correlations obtained for the activity of Mrk~501 observed in 1997 April and for the activity of Mrk~421 observed in 2000 February. We also discuss results of similar correlation obtained for this source by other authors. They report an almost quadratic correlations observed between the evolution of the TeV and X-ray emission. In the second part of this paper we present a phenomenological model which describes the evolution of the synchrotron and inverse Compton emission of a simple spherical homogeneous source. Neglecting the radiative cooling of the particles we derive analytical expressions that describe the evolution. Then we use a numerical code to investigate the impact of radiative cooling on the evolution. The quadratic correlation observed during the decay phase of the fla...

  2. Long term lightcurve of the BL Lac object 1ES 0229+200 at TeV energies

    CERN Document Server

    Cologna, Gabriele; Wagner, Stefan J; Wierzcholska, Alicja; Romoli, Carlo; Kurtanidze, Omar

    2015-01-01

    The high-frequency peaked BL Lac object 1ES 0229+200 (z = 0.14) was first detected in very high energy (VHE, E > 100 GeV) $\\gamma$-rays by the H.E.S.S. (High Energy Stereoscopic System) collaboration in 2006. No flux variability was reported in the initial study and its spectral characteristics have been used to derive constraints on the extragalactic background light (EBL) and on the intergalactic magnetic field (IGMF). 1ES 0229+200 has been observed with H.E.S.S. for $\\sim$130 hours from 2004 to 2013: the full dataset analysed with a more sensitive method will be presented here. The results indicate that the source is not constant and displays flux variability on yearly and monthly timescales. The existence of flux variability affects the derivation of the constraints on the IGMF. The H.E.S.S. observations cover several simultaneous multi-frequency campaigns and the VHE variations are compared with those reported in different bands.

  3. EVN Observations of HESS J1943+213: Evidence for an Extreme TeV BL Lac Object

    CERN Document Server

    Akiyama, Kazunori; Tanaka, Yasuyuki T; Nagai, Hiroshi; Giroletti, Marcello; Honma, Mareki

    2016-01-01

    We report on the 1.6 GHz (18 cm) VLBI observations of the unresolved, steady TeV source HESS J1943+213 located in the Galactic plane, performed with the European VLBI Network (EVN) in 2014. Our new observations with a nearly full EVN array provide the deepest image of HESS J1943+213 at the highest resolution ever achieved, enabling us to resolve the long-standing issues of the source identification. The milliarcsecond-scale structure of HESS J1943+213 has a clear asymmetric morphology, consisting of a compact core and a diffuse jet-like tail. This is broadly consistent with the previous e-EVN observations of the source performed in 2011, and re-analyzed in this work. The core component is characterized by the brightness temperature of $\\gtrsim1.8 \\times 10^9$ K, which is typical for low-luminosity blazars in general. Overall, radio properties of HESS J1943+213 are consistent with the source classification as an "extreme high-frequency-peaked BL Lac object". Remarkably, we note that since HESS J1943+213 does n...

  4. Fermi LAT detection of the first GeV gamma-ray flare from the BL Lac object S5 2007+77

    Science.gov (United States)

    Cutini, Sara

    2016-02-01

    The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope, has observed for the first time on daily time-scales gamma-ray outburst activity from a source positionally consistent with the BL Lac object S5 2007+77.

  5. Multiwavelength Variability Study of the Classical BL Lac Object PKS 0735+178 on Timescales Ranging from Decades to Minutes

    Science.gov (United States)

    Goyal, Arti; Stawarz, Łukasz; Ostrowski, Michał; Larionov, Valeri; Gopal-Krishna; Wiita, Paul J.; Joshi, Santosh; Soida, Marian; Agudo, Iván

    2017-03-01

    We present the results of our power spectral analysis for the BL Lac object PKS 0735+178, utilizing the Fermi-LAT survey at high-energy γ-rays, several ground-based optical telescopes, and single-dish radio telescopes operating at GHz frequencies. The novelty of our approach is that, by combining long-term and densely sampled intra-night light curves in the optical regime, we were able to construct for the first time the optical power spectrum of the blazar for a time domain extending from 23 years down to minutes. Our analysis reveals that: (1) the optical variability is consistent with a pure red noise, for which the power spectral density can be well approximated by a single power law throughout the entire time domain probed; (2) the slope of power spectral density at high-energy γ-rays (∼1) is significantly flatter than that found at radio and optical frequencies (∼2) within the corresponding time variability range; (3) for the derived power spectra, we did not detect any low-frequency flattening, nor do we see any evidence for cutoffs at the highest frequencies down to the noise floor levels due to measurement uncertainties. We interpret our findings in terms of a model where the blazar variability is generated by the underlying single stochastic process (at radio and optical frequencies), or a linear superposition of such processes (in the γ-ray regime). Along with the detailed PSD analysis, we also present the results of our extended (1998–2015) intra-night optical monitoring program and newly acquired optical photo-polarimetric data for the source.

  6. Jet/accretion and Unification for FSRQs/FRII and BL Lac objects/FRI radio galaxies

    CERN Document Server

    Chen, Yongyun; Zhang, Haojing; Xiong, Dingrong; Yu, Xiaoling; Cha, Yongjuan; Li, Bijun; Huang, Xia

    2015-01-01

    We compiled a sample of 24 flat-spectrum radio quasars (FSRQs), 21 BL Lacs, 13 FRI and 12 FRII radio galaxies to study the jet power and broad-line luminosity relation, and the jet power and black hole mass relation. Furthermore, we obtain the histograms of key parameters. Our main results are as the follows:(i) We found that the FSRQs are roughly separated from BL Lacs by the Ledlow-Owen FRI/FRII dividing line in the $\\rm{\\log{P_{jet}}-\\log{M}}$ plane. This result supports the unification model that BL Lacs unify with FRI radio galaxies and FSRQs unify with FRII radio galaxies.(ii)We found that the coefficient of the best-fit linear regression equation of $\\rm{\\log{L_{BLR}}-\\log{P_{jet}}}$ relation is very close to 1 for our sample. The correlation between broad line luminosity and jet power is significant which supports that jet power has a close link with accretion.

  7. X-ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lac Objects

    Science.gov (United States)

    Krawczynski, Henric

    2007-04-01

    In this contribution we discuss models of the X-rays and TeV gamma-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole owing to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constrains on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole 100-1000 G. However, the model fits imply that the magnetic field in the emission region is only 0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to 20 TeV energies. Although the parallel beam model has its own problems, it explains some of the long-standing problems that plague models based on Fermi type particle acceleration, like the presence of a very high minimum Lorentz factor of accelerated particles. We conclude with a brief discussion of the implications of the model for the difference between the processes of jet formation in BL Lac type objects and in quasars.

  8. New High-z Fermi BL Lacs with the Photometric Dropout Technique

    CERN Document Server

    Kaur, A; Ajello, M; Greiner, J; Hartmann, D H; Paliya, V S; Dominguez, A; Bolmer, J; Schady, P

    2016-01-01

    Determining redshifts for BL Lacertae (BL Lac) objects using the traditional spectroscopic method is challenging due to the absence of strong emission lines in their optical spectra. We employ the photometric dropout technique to determine redshifts for this class of blazars using the combined 13 broad-band filters from Swift-UVOT and the multi-channel imager GROND at the MPG 2.2 m telescope at ESO's La Silla Observatory. The wavelength range covered by these 13 filters extends from far ultraviolet to the near-Infrared. We report results on 40 new Fermi detected BL Lacs with the photometric redshifts determinations for 5 sources, with 3FGL J1918.2-4110 being the most distant in our sample at z=2.16. Reliable upper limits are provided for 20 sources in this sample. Using the highest energy photons for these Fermi-LAT sources, we evaluate the consistency with the Gamma-ray horizon due to the extragalactic background light.

  9. New High-z Fermi BL Lacs with the Photometric Dropout Technique

    Science.gov (United States)

    Kaur, A.; Rau, A.; Ajello, M.; Greiner, J.; Hartmann, D. H.; Paliya, V. S.; Domínguez, A.; Bolmer, J.; Schady, P.

    2017-01-01

    Determining redshifts for BL Lacertae (BL Lac) objects using the traditional spectroscopic method is challenging due to the absence of strong emission lines in their optical spectra. We employ the photometric dropout technique to determine redshifts for this class of blazars using the combined 13 broadband filters from Swift-UVOT and the multi-channel imager GROND at the MPG 2.2 m telescope at ESO's La Silla Observatory. The wavelength range covered by these 13 filters extends from far-ultraviolet to the near-infrared. We report results on 40 new Fermi-detected BL Lacs with the photometric redshift determinations for five sources, with 3FGL J1918.2–4110 being the most distant in our sample at z = 2.16. Reliable upper limits are provided for 20 sources in this sample. Using the highest energy photons for these Fermi-LAT sources, we evaluate the consistency with the gamma-ray horizon due to the extragalactic background light.

  10. Parsec-scale Magnetic-Field Structures in HEAO-1 BL Lacs

    CERN Document Server

    Kharb, P; Shastri, P

    2007-01-01

    We present very long baseline interferometry polarization images of an X-ray selected sample of BL Lacertae objects belonging to the first High Energy Astronomy Observatory (HEAO-1) and the ROSAT-Green Bank (RGB) surveys. These are primarily high-energy-peaked BL Lacs (HBLs) and exhibit core-jet radio morphologies on pc-scales. They show moderately polarized jet components, similar to those of low-energy-peaked BL Lacs (LBLs). The fractional polarization in the unresolved cores of the HBLs is, on average, lower than in the LBLs, while the fractional polarizations in the pc-scale jets of HBLs and LBLs are comparable. However a difference is observed in the orientation of the inferred jet magnetic fields -- while LBL jets are well-known to preferentially exhibit transverse magnetic fields, the HBL jets tend to display longitudinal magnetic fields. Although a `spine-sheath' jet velocity structure, along with larger viewing angles for HBLs could produce the observed magnetic field configuration, differences in ot...

  11. Fermi-LAT detection of hard spectrum and enhanced gamma-ray emission from the BL Lac object PKS 1717+177

    Science.gov (United States)

    Ciprini, Stefano

    2015-12-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed a gamma-ray flare from a source positionally consistent with the BL Lac object PKS 1717+177 (also known as S3 1717+17, OT 129, and 3FGL J1719.2+1744, Acero et al. 2015, ApJS, 218, 23), with radio coordinates (J2000.0), R.A.: 259.804368 deg, Dec.: 17.751788 deg (Johnston et al. 1995, AJ, 110, 880).

  12. Fermi LAT detection of the first GeV gamma-ray flare from the BL Lac object TXS 2241+406

    Science.gov (United States)

    Buson, Sara

    2015-02-01

    The Large Area Telescope (LAT) onboard the Fermi Gamma-ray Space Telescope, has observed for the first time on daily timescales gamma-ray outburst activity from a source positionally consistent with the BL Lac object TXS 2241+406 (a.k.a.3FGL J2244.1+4057, Acero et al. 2015, arXiv:1501.02003) at RA=341.05305 deg, Dec=40.95378 deg (J2000, Beasley et al. 2002, ApJS, 141, 13) with redshift z=1.171 (Shaw et al. 2012, ApJ, 748, 49).

  13. Fermi LAT detection of increasing GeV gamma-ray activity from the high-energy peaked BL Lac object 1ES 1959+650

    Science.gov (United States)

    Ciprini, Stefano; Fermi Large Area Telescope Collaboration

    2015-10-01

    The Large Area Telescope (LAT), one of two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray emission from a source positionally consistent with the very-high energy peaked BL Lac object 1ES 1959+650 (also known as TXS 1959+650 and 3FGL J2000.0+6509, Acero et al. 2015, ApJS 218, 23) with radio coordinates (J2000) R.A.: 299.999384 deg, Dec.: 65.148514 deg (Beasley et al. 2002, ApJS, 141, 13). This source has a redshift z=0.047 (Schachter et al. 1993, ApJ, 412, 541).

  14. Fermi-LAT, FACT, MAGIC and VERITAS detection of increasing gamma-ray activity from the high-energy peaked BL Lac object 1ES 1959+650

    Science.gov (United States)

    Buson, S.; Magill, J. D.; Dorner, D.; Biland, A.; Mirzoyan, R.; Mukherjee, R.

    2016-04-01

    The Fermi-LAT, FACT, MAGIC and VERITAS collaborations report the detection of enhanced gamma-ray activity from a source positionally consistent with the very-high-energy peaked BL Lac object 1ES 1959+650 (a.k.a 3FGL J2000.0+6509, in the 3rd LAT source catalog, 3FGL, Acero et al. 2015, ApJS 218, 23) with radio coordinates (J2000) R.A.: 299.999384 deg, Dec.: 65.148514 deg (Beasley et al. 2002, ApJS, 141, 13). This source has a redshift z=0.047 (Schachter et al. 1993, ApJ, 412, 541).

  15. Time Series Photometry of KZ Lacertae

    Science.gov (United States)

    Joner, Michael D.

    2016-01-01

    We present BVRI time series photometry of the high amplitude delta Scuti star KZ Lacertae secured using the 0.9-meter telescope located at the Brigham Young University West Mountain Observatory. In addition to the multicolor light curves that are presented, the V data from the last six years of observations are used to plot an O-C diagram in order to determine the ephemeris and evaluate evidence for period change. We wish to thank the Brigham Young University College of Physical and Mathematical Sciences as well as the Department of Physics and Astronomy for their continued support of the research activities at the West Mountain Observatory.

  16. MAGIC detection of short-term variability of the high-peaked BL Lac object 1ES 0806+524

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Babic, A; Bangale, P; Barrio, J A; González, J Becerra; Bednarek, W; Bernardini, E; Biasuzzi, B; Biland, A; Blanch, O; Bonnefoy, S; Bonnoli, G; Borracci, F; Bretz, T; Carmona, E; Carosi, A; 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; Wilhelmi, E de O na; Mendez, C Delgado; Di Pierro, F; Prester, D Dominis; Dorner, D; Doro, M; Einecke, S; Eisenacher, D; Elsaesser, D; Fernández-Barral, A; Fidalgo, D; Fonseca, M V; Font, L; Frantzen, K; Fruck, C; Galindo, D; López, R J García; Garczarczyk, M; Terrats, D Garrido; Gaug, M; Godinović, N; noz, A González Mu; Gozzini, S R; Hadasch, D; Hanabata, Y; Hayashida, M; Herrera, J; 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; Longo, F; López, M; López-Coto, R; López-Oramas, A; Lorenz, E; Lozano, I; Makariev, M; Mallot, K; Maneva, G; Mannheim, K; Maraschi, L; Marcote, B; Mariotti, M; Martínez, M; Mazin, D; Menzel, U; Miranda, J M; Mirzoyan, R; Moralejo, A; Munar-Adrover, P; Nakajima, D; Neustroev, V; Niedzwiecki, A; Rosillo, M Nievas; Nilsson, K; Nishijima, K; Noda, K; Orito, R; Overkemping, A; Paiano, S; Palatiello, M; Paneque, D; Paoletti, R; Paredes, J M; Paredes-Fortuny, X; Persic, M; Poutanen, J; Moroni, P G Prada; Prandini, E; Puljak, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Garcia, J Rodriguez; Saito, T; Saito, K; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Stamerra, A; Steinbring, T; Strzys, M; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Thaele, J; Torres, D F; Toyama, T; Treves, A; Vogler, P; Will, M; Zanin, R; Berger, K; Buson, S; D'Ammando, F; Gasparrini, D; Hovatta, T; Max-Moerbeck, W; Readhead, A; Richards, J

    2015-01-01

    The high-frequency-peaked BL Lac (HBL) 1ES 0806+524 (z = 0.138) was discovered in VHE $\\gamma$ rays in 2008. Until now, the broad-band spectrum of 1ES 0806+524 has been only poorly characterized, in particular at high energies. We analysed multiwavelength observations from $\\gamma$ rays to radio performed from 2011 January to March, which were triggered by the high activity detected at optical frequencies. These observations constitute the most precise determination of the broad-band emission of 1ES 0806+524 to date. The stereoscopic MAGIC observations yielded a $\\gamma$-ray signal above 250 GeV of $(3.7 \\pm 0.7)$ per cent of the Crab Nebula flux with a statistical significance of 9.9 $\\sigma$. The multiwavelength observations showed significant variability in essentially all energy bands, including a VHE $\\gamma$-ray flare that lasted less than one night, which provided unprecedented evidence for short-term variability in 1ES 0806+524. The spectrum of this flare is well described by a power law with a photon...

  17. On the redshift of the very high energy {\\gamma}-ray BL Lac object S2 0109+22

    CERN Document Server

    Paiano, Simona; Falomo, Renato; Scarpa, Riccardo; Treves, Aldo

    2016-01-01

    The determination of the redshift of extragalactic gamma ray sources is of fundamental importance for the interpretation of their emission models and extragalactic population studies, AGN classification schemes, and to study the interaction with the extragalactic background light. Here we focus on the BL Lac S2 0109+22, recently detected at very high energies. We obtained a high signal-to-noise optical spectrum at Gran Telescopio Canarias for the source over the spectral range 4000-10000 Angstrom, to search for spectral features of the host galaxy and/or of the nuclear source and it was compared with previous observations in order to confirm and/or dispute its redshift determination. We find the S2 0109+22 optical spectrum is well represented by a power law continuum without any absorption or emission feature of Equivalent Width >0.1 Angstrom. Based on the new optical spectrum we are able to set a redshift lower limit z>0.35, assuming the source is hosted by a massive elliptical galaxy typical for this class ...

  18. Photographic photometry of compact extragalactic objects. VI. [BL Lac OJ 287, B2 1101+38, IZw 1727+50, IZw 0051+12, 3C 351, 3C 120

    Energy Technology Data Exchange (ETDEWEB)

    Hagen-Thorn, V.A.; Perevozchikova, A.I.; Skulova, N.M.; Ershtadt, S.G.; Yakovleya, V.A.

    1978-01-01

    The results of photographic photometry in B band of 7 compact extragalactic objects for 1975 are given. The light curves of BL Lac (1968-1975) and OJ 287 (1971-1975) are investigated for periodicity. It is found that the light curves of both objects seem to have components with amplitudes of 0.5 m and periods of 178 days for BL Lac and 184 days for OJ 287. 11 figures, 1 table.

  19. X-ray and TeV Gamma-Ray Emission from Parallel Electron-Positron or Electron-Proton Beams in BL Lac Objects

    CERN Document Server

    Krawczynski, H

    2006-01-01

    In this paper we discuss models of the X-rays and TeV gamma-ray emission from BL Lac objects based on parallel electron-positron or electron-proton beams that form close to the central black hole owing to the strong electric fields generated by the accretion disk and possibly also by the black hole itself. Fitting the energy spectrum of the BL Lac object Mrk 501, we obtain tight constrains on the beam properties. Launching a sufficiently energetic beam requires rather strong magnetic fields close to the black hole 100-1000 G. However, the model fits imply that the magnetic field in the emission region is only 0.02 G. Thus, the particles are accelerated close to the black hole and propagate a considerable distance before instabilities trigger the dissipation of energy through synchrotron and self-Compton emission. We discuss various approaches to generate enough power to drive the jet and, at the same time, to accelerate particles to 20 TeV energies. Although the parallel beam model has its own problems, it ex...

  20. Discovery of VHE gamma-ray emission from the BL Lac object B3 2247+381 with the MAGIC telescopes

    CERN Document Server

    Aleksić, J; Antonelli, L A; Antoranz, P; Asensio, M; Backes, M; Barrio, J A; Bastieri, D; González, J Becerra; Bednarek, W; Berdyugin, A; Berger, K; Bernardini, E; Biland, A; Blanch, O; Bock, R K; Boller, A; Bonnoli, G; Tridon, D Borla; Braun, I; Bretz, T; Cañellas, A; Carmona, E; Carosi, A; Colin, P; Colombo, E; Contreras, J L; Cortina, J; Cossio, L; Covino, S; Dazzi, F; De Angelis, A; De Caneva, G; del Pozo, E De Cea; De Lotto, B; Mendez, C Delgado; Ortega, A Diago; Doert, M; Domínguez, A; Prester, D Dominis; Dorner, D; Doro, M; Elsaesser, D; Ferenc, D; Fonseca, M V; Font, L; Fruck, C; López, R J García; Garczarczyk, M; Garrido, D; Giavitto, G; Godinović, N; Hadasch, D; Häfner, D; Herrero, A; Hildebrand, D; Höhne-Mönch, D; Hose, J; Hrupec, D; Huber, B; Jogler, T; Kellermann, H; Klepser, S; Krähenbühl, T; Krause, J; La Barbera, A; Lelas, D; Leonardo, E; Lindfors, E; Lombardi, S; López, M; López-Oramas, A; Lorenz, E; Makariev, M; Maneva, G; Mankuzhiyil, N; Mannheim, K; Maraschi, L; Mariotti, M; Martínez, M; Mazin, D; Meucci, M; Miranda, J M; Mirzoyan, R; Miyamoto, H; Moldón, J; Moralejo, A; Munar-Adrover, P; Nieto, D; Nilsson, K; Orito, R; Oya, I; Paneque, D; Paoletti, R; Pardo, S; Paredes, J M; Partini, S; Pasanen, M; Pauss, F; Perez-Torres, M A; Persic, M; Peruzzo, L; Pilia, M; Pochon, J; Prada, F; Moroni, P G Prada; Prandini, E; Puljak, I; Reichardt, I; Reinthal, R; Rhode, W; Ribó, M; Rico, J; Rügamer, S; Saggion, A; Saito, K; Saito, T Y; Salvati, M; Satalecka, K; Scalzotto, V; Scapin, V; Schultz, C; Schweizer, T; Shayduk, M; Shore, S N; Sillanpää, A; Sitarek, J; Snidaric, I; Sobczynska, D; Spanier, F; Spiro, S; Stamatescu, V; Stamerra, A; Steinke, B; Storz, J; Strah, N; Surić, T; Takalo, L; Takami, H; Tavecchio, F; Temnikov, P; Terzić, T; Tescaro, D; Teshima, M; Tibolla, O; Torres, D F; Treves, A; Uellenbeck, M; Vankov, H; Vogler, P; Wagner, R M; Weitzel, Q; Zabalza, V; Zandanel, F; Zanin, R; Kadenius, V; Weidinger, M; Buson, S

    2012-01-01

    We study the non-thermal jet emission of the BL Lac object B3 2247+381 during a high optical state. The MAGIC telescopes observed the source during 13 nights between September 30th and October 30th 2010, collecting a total of 14.2 hours of good quality very high energy (VHE) $\\gamma$-ray data. Simultaneous multiwavelength data was obtained with X-ray observations by the Swift satellite and optical R-band observations at the KVA-telescope. We also use high energy $\\gamma$-ray (HE, 0.1 GeV-100 GeV) data from the Fermi satellite. The BL Lac object B3 2247+381 (z=0.119) was detected, for the first time, at VHE $\\gamma$-rays at a statistical significance of 5.6 $\\sigma$. A soft VHE spectrum with a photon index of -3.2 $\\pm$ 0.6 was determined. No significant short term flux variations were found. We model the spectral energy distribution using a one-zone SSC-model, which can successfully describe our data.

  1. The Sedentary Survey of Extreme High Energy Peaked BL Lacs. II. The Catalog and Spectral Properties

    CERN Document Server

    Giommi, P; Perri, M; Padovani, P

    2004-01-01

    The multi-frequency `Sedentary Survey' is a deep, statistically complete, radio flux limited sample comprising 150 BL Lacertae objects distinguished by their extremely high X-ray to radio flux ratio, ranging from five hundred to over five thousand times that of typical BL Lacs discovered in radio surveys. This paper presents the final, 100% identified, catalog together with the optical, X-ray and broad-band SEDs constructed combining literature multi-frequency data with non-simultaneous optical observations and BeppoSAX X-ray data, when available. The SEDs confirm that the peak of the synchrotron power in these objects is located at very high energies. BeppoSAX wide band X-ray observations show that, in most cases, the X-ray spectra are convex and well described by a logarithmic parabola model peaking (in a E f(E) vs E representation) between 0.02 to several keV. Owing to the high synchrotron energies involved most of the sources in the catalog are likely to be TeV emitters, with the closest and brightest one...

  2. Swift XRT and UVOT deep observations of the high energy peaked BL Lac object PKS 0548-322 close to its brightest state

    CERN Document Server

    Perri, M; Giommi, P; Massaro, E; Nesci, R; Tramacere, A; Capalbi, M; Cusumano, G; Chincarini, G; Tagliaferri, G; Burrows, D N; Vanden Berk, D E; Gehrels, N; Sambruna, R M

    2006-01-01

    We present the results of a spectral analysis of 5 Swift XRT and UVOT observations of the BL Lac object PKS 0548-322 carried out over the period April-June 2005. The X-ray flux of this high energy peaked BL Lac (HBL) source was found to be approximately constant at a level of F(2-10 keV) ~ 4x10^-11 erg cm^-2 s^-1, a factor of 2 brighter than when observed by BeppoSAX in 1999 and close to the maximum intensity reported in the Einstein Slew Survey. The very good statistics obtained in the 0.3-10 keV Swift X-ray spectrum allowed us to detect highly significant deviations from a simple power law spectral distribution. A log-parabolic model describes well the X-ray data and gives a best fit curvature parameter of 0.18 and peak energy in the Spectral Energy Distribution of about 2 keV. The UV spectral data from Swift UVOT join well with a power law extrapolation of the soft X-ray data points suggesting that the same component is responsible for the observed emission in the two bands. The combination of synchrotron ...

  3. VERITAS detection of $\\gamma$-ray flaring activity from the BL Lac object 1ES 1727+502 during bright moonlight observations

    CERN Document Server

    Archambault, S; Beilicke, M; Benbow, W; Bird, R; Biteau, J; Bouvier, A; Bugaev, V; Cardenzana, J V; Cerruti, M; Chen, X; Ciupik, L; Connolly, M P; Cui, W; Dickinson, H J; Dumm, J; Eisch, J D; Errando, M; Falcone, A; Feng, Q; Finley, J P; Fleischhack, H; Fortin, P; Fortson, L; Furniss, A; Gillanders, G H; Griffin, S; Griffiths, S T; Grube, J; Gyuk, G; Håkansson, N; Hanna, D; Holder, J; Humensky, T B; Johnson, C A; Kaaret, P; Kar, P; Kertzman, M; Khassen, Y; Kieda, D; Krause, M; Krennrich, F; Kumar, S; Lang, M J; Maier, G; McArthur, S; McCann, A; Meagher, K; Millis, J; Moriarty, P; Mukherjee, R; Nieto, D; de Bhróithe, A O'Faoláin; Ong, R A; Otte, A N; Park, N; Pohl, M; Popkow, A; Prokoph, H; Pueschel, E; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Richards, G T; Roache, E; Santander, M; Sembroski, G H; Shahinyan, K; Smith, A W; Staszak, D; Telezhinsky, I; Tucci, J V; Tyler, J; Varlotta, A; Vincent, S; Wakely, S P; Weinstein, A; Welsing, R; Wilhelm, A; Williams, D A; Zitzer, B; Hughes, Z D

    2015-01-01

    During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHE, $E>100$ GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background moonlight. Observations with the VERITAS telescopes in the standard configuration are performed only with a moon illumination less than 35$\\%$ of full moon. Since 2012, the VERITAS collaboration has implemented a new observing mode under bright moonlight, by either reducing the voltage applied to the PMTs (reduced-high-voltage configuration, RHV), or by utilizing UV-transparent filters. While these operating modes result in lower sensitivity and increased energy thresholds, the extension of the available observing time is useful for monitoring variable sources such as blazars and sources requiring spectral measurements at the highest energies. In this paper we report the detection of $\\gamma$-ray flaring activity from the BL Lac object 1ES 1727+502 during RHV observations. Thi...

  4. Fermi and Swift observations of a rapid flare in the BL Lac object SDSS J084411.67+531250.7 (NVSS J084411+531250)

    Science.gov (United States)

    Ciprini, Stefano

    2015-04-01

    The Large Area Telescope (LAT), one of the two instruments on the Fermi Gamma-ray Space Telescope, has observed increasing gamma-ray flux from a source positionally consistent with the optically-selected and polarized (Smith et al. 2007, ApJ, 663, 118) BL Lac object SDSS J084411.67+531250.7 (also known as NVSS J084411+531250, BZB J0844+5312, and 3FGL J0843.9+5311, Acero et al. 2015, arXiv:1501.02003), with optical counterpart coordinates (J2000.0) R.A.: 131.04872 deg, Dec.: 53.21407 deg (Adelman-McCarthy et. al 2008, ApJS, 175, 297).

  5. Studies of inverse-Compton emission in the Crab Nebula and the BL Lac object 1ES 1959+650

    Science.gov (United States)

    O'Faolain de Bhroithe, Anna

    This thesis concerns the study of inverse-Compton emission from two astrophysical sources. The first object, 1ES 1959+650, is a nearby active galactic nucleus. This source was observed as part of the VERITAS blazar monitoring programme in the hopes of detecting it in the midst of a dramatic flaring event. Over the course of these monitoring observations which span four years, a significant detection of the source in its low state was accumulated. The spectral energy distribution of this source was analysed from optical to VHE and was modelled with a synchrotron self-Compton model with an additional external Compton component. The parameters obtained cannot be fully explained by first-order Fermi acceleration at parallel shocks, and instead may suggest particle acceleration at oblique subluminal shocks, or that 1ES 1959+650 may consist of an inhomogeneous jet with a fast inner spine and slower-moving outer cocoon. The second source is the famous Crab Nebula, for years considered the standard candle of X-ray to VHE gamma-ray astronomy. VERITAS observed the Crab Nebula during the recent flare of the high-energy synchrotron component of the source in March 2013. No enhanced VHE emission was detected, but the observations facilitated the calculation of upper limits on any extra VHE spectral component emerging during the flare. A wealth of archival VHE Crab Nebula data also exists, spanning many years. An extended VHE data set of the source from 2000 to 2013 was compiled from Whipple 10m Telescope and VERITAS observations. This data set was searched for short-term flaring activity, but no evidence of this behaviour was found. A slight decrease in the long-term flux of the nebula was detected in the VERITAS data in 2011. This could possibly be correlated with increasing instability of the aerosol content of the local atmosphere around the VERITAS site.

  6. Non-radial motion in the TeV blazar S5 0716+714 The pc-scale kinematics of a BL Lac Object

    CERN Document Server

    Britzen, S; Witzel, A; Agudo, I; Aller, M F; Aller, H D; Karouzos, M; Eckart, A; Zensus, J A; 10.1051/0004-6361/200810875

    2010-01-01

    For the BL Lac object S5 0716+714 conflicting apparent velocities of jet component motion have been reported in the literature. This object is an intra-day variable source and suited to investigate a possible correlation between kinematic properties and flux-density variability on different timescales. We (re-)analyze 50 VLBI observations obtained with the VLBA at 5 different frequencies (5 to 43 GHz) between 1992.73 and 2006.32. We analyze the jet component motion in detail taking care not only to account for motion in the radial but also in the orthogonal direction. We study the evolution of the jet ridge line and search for correlations between radio band light curves and the kinematic properties of the jet components. We present an alternative kinematic scenario for jet component motion in S5 0716+714 with apparent stationarity of jet components (with regard to their core separation) with time. Jet components, however, do seem to move significantly non-radially with regard to their position angle and in a...

  7. Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects Superluminal Motion of Gamma-Ray Bright Blazars

    CERN Document Server

    Jorstad, S G; Mattox, J R; Wehrle, A E; Bloom, S D; Yurchenko, A V; Jorstad, Svetlana G; Marscher, Alan P; Mattox, John R; Wehrle, Ann E; Bloom, Steven D; Yurchenko, Alexei V

    2001-01-01

    We present the results of a program to monitor the structure of the radio emission in 42 $\\gamma$-ray bright blazars (31 quasars and 11 BL Lac objects) with the VLBA at 43, 22, and occasionally 15 and 8.4 GHz, over the period from November 1993 to July 1997. We determine proper motions in 33 sources and find that the apparent superluminal motions in $\\gamma$-ray sources are much faster than for the general population of bright compact radio sources. This follows the strong dependence of the $\\gamma$-ray flux on the level of relativistic beaming for both external-radiation Compton and synchrotron self-Compton emission. There is a positive correlation (correlation coefficient $r$=0.45) between the flux density of the VLBI core and the $\\gamma$-ray flux and a moderate correlation (partial correlation coefficient $r$=0.31) between $\\gamma$-ray apparent luminosity and superluminal velocities of jet components, as expected if the $\\gamma$-ray emission originates in a very compact region of the relativistic jet and ...

  8. Location of the Gamma-Ray Flaring Emission in the Parse-Scale Jet of the BL Lac Object AO 0235+164

    CERN Document Server

    Agudo, Ivan; Jorstad, Svetlana G; Larionov, Valeri M; Gomez, Jose L; Lahteenmaki, Anne; Smith, Paul S; Nilsson, Kari; Readhead, Anthony C S; Aller, Margo F; Heidt, Jochen; Gurwell, Mark; Thum, Clemens; Wehrle, Ann E; Kurtanidze, Omar M

    2011-01-01

    We locate the gamma-ray and lower frequency emission in flares of the BL Lac object AO 0235+164 at >12pc in the jet of the source from the central engine. We employ time-dependent multi-spectral-range flux and linear polarization monitoring observations, as well as ultra-high resolution (~0.15 milliarcsecond) imaging of the jet structure at lambda=7mm. The time coincidence in the end of 2008 of the propagation of the brightest superluminal feature detected in AO 0235+164 (Qs) with an extreme multi-spectral-range (gamma-ray to radio) outburst, and an extremely high optical and 7mm (for Qs) polarization degree provides strong evidence supporting that all these events are related. This is confirmed at high significance by probability arguments and Monte-Carlo simulations. These simulations show the unambiguous correlation of the gamma-ray flaring state in the end of 2008 with those in the optical, millimeter, and radio regime, as well as the connection of a prominent X-ray flare in October 2008, and of a series ...

  9. The WEBT campaign on the BL Lac object PG 1553+113 in 2013. An analysis of the enigmatic synchrotron emission

    CERN Document Server

    Raiteri, C M; Villata, M; Larionov, V M; Acosta-Pulido, J A

    2015-01-01

    A multifrequency campaign on the BL Lac object PG 1553+113 was organized by the Whole Earth Blazar Telescope (WEBT) in 2013 April-August, involving 19 optical, two near-IR, and three radio telescopes. The aim was to study the source behaviour at low energies during and around the high-energy observations by the Major Atmospheric Gamma-ray Imaging Cherenkov (MAGIC) telescopes in April-July. We also analyse the UV and X-ray data acquired by the Swift and XMM-Newton satellites in the same period. The WEBT and satellite observations allow us to detail the synchrotron emission bump in the source spectral energy distribution (SED). In the optical we found a general bluer-when-brighter trend. The X-ray spectrum remained stable during 2013, but a comparison with previous observations suggests that it becomes harder when the X-ray flux increases. The long XMM-Newton exposure reveals a curved X-ray spectrum. In the SED, the XMM-Newton data show a hard near-UV spectrum, while Swift data display a softer shape that is co...

  10. Discovery of VHE \\gamma-ray emission and multi-wavelength observations of the BL Lac object 1RXS J101015.9-311909

    CERN Document Server

    Abramowski, A; Aharonian, F; Akhperjanian, A G; Anton, G; Balzer, A; Barnacka, A; Becherini, Y; Becker, J; Bernlöhr, K; Birsin, E; Biteau, J; Bochow, A; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Büsching, I; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Charbonnier, A; Chaves, R C G; Cheesebrough, A; Cologna, G; Conrad, J; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Egberts, K; Eger, P; Espigat, P; Fallon, L; Fegan, S; Feinstein, F; Fernandes, M V; Fiasson, A; Fontaine, G; Förster, A; Füßling, M; Gallant, Y A; Gast, H; Gérard, L; Gerbig, D; Giebels, B; Glicenstein, J F; Glück, B; Göring, D; Häffner, S; Hague, J D; Hahn, J; Hampf, D; Harris, J; Hauser, M; Heinz, S; Heinzelmann, G; Henri, G; Hermann, G; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; de Jager, O C; Jahn, C; Jamrozy, M; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Keogh, D; Khélifi, B; Klochkov, D; Kluźniak, W; Kneiske, T; Komin, Nu; Kosack, K; Kossakowski, R; Krayzel, F; Laffon, H; Lamanna, G; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Masbou, J; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Moderski, R; Mohamed, M; Moulin, E; Naumann, C L; Naumann-Godo, M; de Naurois, M; Nedbal, D; Nekrassov, D; Nguyen, N; Nicholas, B; Niemiec, J; Nolan, S J; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Pühlhofer, G; Punch, M; Quirrenbach, A; Raue, M; Rayner, S M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Ripken, J; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sheidaei, F; Skilton, J L; Sol, H; Spengler, G; Stawarz, Ł; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorobiov, S; Vorster, M; Wagner, S J; Ward, M; White, R; Wierzcholska, A; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S

    2012-01-01

    1RXS J101015.9-311909 is a galaxy located at a redshift of z=0.14 hosting an active nucleus belonging to the class of bright BL Lac objects. Observations at high (HE, E > 100 MeV) and very high (VHE, E > 100 GeV) energies provide insights into the origin of very energetic particles present in such sources and the radiation processes at work. We report on results from VHE observations performed between 2006-10 with H.E.S.S. H.E.S.S. data have been analysed with enhanced analysis methods, making the detection of faint sources more significant. VHE emission at a position coincident with 1RXS J101015.9-311909 is detected with H.E.S.S. for the first time. In a total good-quality livetime of about 49 h, we measure 263 excess counts, corresponding to a significance of 7.1\\sigma. The photon spectrum above 0.2 TeV can be described by a power-law with a photon index of \\Gamma\\ = 3.08\\pm0.42_{stat}\\pm0.20_{sys}. The integral flux above 0.2 TeV is about 0.8% of the flux of the Crab nebula and shows no significant variabi...

  11. Constraining the parameter space of the one-zone synchrotron-self-Compton model for GeV-TeV detected BL Lac objects

    CERN Document Server

    Cerruti, Matteo; Zech, Andreas

    2013-01-01

    The one-zone synchrotron-self-Compton (SSC) model aims to describe the spectral energy distribution (SED) of BL Lac objects via synchrotron emission by a non-thermal population of electrons and positrons in a single homogeneous emission region, partially upscattered to gamma-rays by the particles themselves. The model is usually considered as degenerate, given that the number of free parameters is higher than the number of observables. It is thus common to model the SED by choosing a single set of values for the SSC-model parameters that provide a good description of the data, without studying the entire parameter space. We present here a new numerical algorithm which permits us to find the complete set of solutions, using the information coming from the detection in the GeV and TeV energy bands. The algorithm is composed of three separate steps: we first prepare a grid of simulated SEDs and extract from each SED the values of the observables; we then parametrize each observable as a function of the SSC param...

  12. Perplexing correlations between Gamma-ray emission and parsec-scale jet orientation variations in the BL Lac object S5 0716+714

    CERN Document Server

    Rani, B; Marscher, A P; Jorstad, S G; Hodgson, J A; Fuhrmann, L; Zensus, J A

    2015-01-01

    The analysis of $\\gamma$-ray flux variability along with the parsec-scale jet kinematics suggests that the high-energy radiation in the BL Lac object S5 0716+714 has a significant correlation with the mm-VLBI core flux density and with the local orientation of the inner jet flow. For the first time in any blazar, we report a significant correlation between the $\\gamma$-ray flux variations and the variations in the local orientation of the jet outflow (position angle). We find that the $\\gamma$-ray flux variations lead the 7~mm VLBI core flux variations by 82$\\pm$32~days, which suggests that the high-energy emission in S5 0716+714 is coming from a region located 3.8$\\pm$1.9~parsecs closer to the central black hole than the "core" seen on the mm-VLBI images. The results imply a strong physical and casual connection between $\\gamma$-ray emission and the inner jet morphology in the source.

  13. Discovery of very high energy gamma-ray emission from the BL Lac object PKS 0301-243 with H.E.S.S

    CERN Document Server

    Abramowski, A; Aharonian, F; Ait, F; Akhperjanian, A G; Angüner, E; Anton, G; Balenderan, S; Balzer, A; Barnacka, A; Becherini, Y; Becker, J; Bernlöhr, K; Birsin, E; Bissaldi, E; Biteau, J; Böttcher, M; Boisson, C; Bolmont, J; Bordas, P; Brucker, J; Brun, F; Brun, P; Bulik, T; Carrigan, S; Casanova, S; Cerruti, M; Chadwick, P M; Chalme-Calvet, R; Chaves, R C G; Cheesebrough, A; Chrétien, M; Colafrancesco, S; Cologna, G; Conrad, J; Couturier, C; Dalton, M; Daniel, M K; Davids, I D; Degrange, B; Deil, C; deWilt, P; Dickinson, H J; Djannati-Ataï, A; Domainko, W; Drury, L O'C; Dubus, G; Dutson, K; Dyks, J; Dyrda, M; Edwards, T; Egberts, K; Eger, P; Espigat, P; Farnier, C; Fegan, S; Feinstein, F; Fernandes, M V; Fernandez, D; Fiasson, A; Fontaine, G; Förster, A; Füssling, M; Gajdus, M; Gallant, Y A; Garrigoux, T; Giebels, B; Glicenstein, J F; Grondin, M -H; Grudzìnska, M; Häffner, S; Hague, J D; Hahn, J; Harris, J; Heinzelmann, G; Henri, G; Hermann, G; Hervet, O; Hillert, A; Hinton, J A; Hofmann, W; Hofverberg, P; Holler, M; Horns, D; Jacholkowska, A; Jahn, C; Jamrozy, M; Janiak, M; Jankowsky, F; Jung, I; Kastendieck, M A; Katarzyński, K; Katz, U; Kaufmann, S; Khélifi, B; Kieffer, M; Klepser, S; Klochkov, D; Kluźniak, W; Kneiske, T; Kolitzus, D; Komin, Nu; Kosack, K; Krakau, S; Krayzel, F; Krüger, P P; Laffon, H; Lamanna, G; Lefaucheur, J; Lemoine-Goumard, M; Lenain, J -P; Lennarz, D; Lohse, T; Lopatin, A; Lu, C -C; Marandon, V; Marcowith, A; Marx, R; Maurin, G; Maxted, N; Mayer, M; McComb, T J L; Medina, M C; Méhault, J; Menzler, U; Meyer, M; Moderski, R; Mohamed, M; Moulin, E; Murach, T; Naumann, C L; de Naurois, M; Nedbal, D; Niemiec, J; Nolan, S J; Oakes, L; Ohm, S; Wilhelmi, E de Oña; Opitz, B; Ostrowski, M; Oya, I; Panter, M; Parsons, R D; Arribas, M Paz; Pekeur, N W; Pelletier, G; Perez, J; Petrucci, P -O; Peyaud, B; Pita, S; Poon, H; Pühlhofer, G; Punch, M; Quirrenbach, A; Raab, S; Raue, M; Reimer, A; Reimer, O; Renaud, M; Reyes, R de los; Rieger, F; Rob, L; Rosier-Lees, S; Rowell, G; Rudak, B; Rulten, C B; Sahakian, V; Sanchez, D A; Santangelo, A; Schlickeiser, R; Schüssler, F; Schulz, A; Schwanke, U; Schwarzburg, S; Schwemmer, S; Sol, H; Spengler, G; Spies, F; Stawarz, L; Steenkamp, R; Stegmann, C; Stinzing, F; Stycz, K; Sushch, I; Szostek, A; Tavernet, J -P; Terrier, R; Tluczykont, M; Trichard, C; Valerius, K; van Eldik, C; Vasileiadis, G; Venter, C; Viana, A; Vincent, P; Völk, H J; Volpe, F; Vorster, M; Wagner, S J; Wagner, P; Ward, M; Weidinger, M; Weitzel, Q; White, R; Wierzcholska, A; Willmann, P; Wörnlein, A; Wouters, D; Zacharias, M; Zajczyk, A; Zdziarski, A A; Zech, A; Zechlin, H -S

    2013-01-01

    The active galactic nucleus PKS 0301-243 (z=0.266) is a high-synchrotron-peaked BL Lac object that is detected at high energies (HE, 100 MeV 100 GeV) by the High Energy Stereoscopic System (H.E.S.S.) from observations between September 2009 and December 2011 for a total live time of 34.9 hours. Gamma rays above 200 GeV are detected at a significance of 9.4{\\sigma}. A hint of variability at the 2.5{\\sigma} level is found. An integral flux I(E > 200 GeV) = (3.3 +/- 1.1_stat +/- 0.7_syst)e-12 ph cm^-2s^-1 and a photon index {\\Gamma} = 4.6 +/- 0.7_stat +/- 0.2_syst are measured. Multi-wavelength light curves in HE, X-ray and optical bands show strong variability, and a minimal variability timescale of eight days is estimated from the optical light curve. A single-zone leptonic synchrotron self-Compton scenario satisfactorily reproduces the multi-wavelength data. In this model, the emitting region is out of equipartition and the jet is particle dominated. Because of its high redshift compared to other sources obse...

  14. Observations of the high-energy peaked BL Lac object H 1426+428 with the solar tower atmospheric Cherenkov effect experiment

    Science.gov (United States)

    Mueller, Carsten

    The Solar Tower Atmospheric Cherenkov Effect Experiment (STACEE) was an atmospheric Cherenkov telescope operational until June 2007, which detected cosmic gamma rays by means of the wavefront-sampling technique. Using 64 of the large heliostats available at the National Solar Thermal Test Facility (NSTTF) near Albuquerque, New Mexico, its total mirror area of 2378 m 2 allowed it to achieve energy thresholds between 150 and 200 GeV. Following a review of the field of gamma-ray astrophysics and Active Galactic Nuclei, this work provides a detailed description of the detector, along with an introduction to simulation and data analysis techniques. During the springs of 2003 and 2004, STACEE observed the High-Energy-Peaked BL Lac object H 1426+428, an established emitter of gamma rays in the TeV energy range. A full analysis of these data reveals that STACEE did not detect a statistically significant gamma-ray excess from H 1426+428 in either data set. With the help of detailed detector simulations, upper limits on the integrated gamma ray fluxes, phi int, at the 95% confidence level are obtained for both observing seasons: phi int(E > 163 GeV) 165 GeV) < 0.78·10-6 m-2 s-1 for 2003 and 2004, respectively. The derived upper limits are discussed in the context of the results obtained by other gamma-ray observatories.

  15. VERITAS Detection of γ-Ray Flaring Activity From the BL Lac Object 1ES 1727+502 During Bright Moonlight Observations

    Science.gov (United States)

    Archambault, S.; Archer, A.; Beilicke, M.; Benbow, W.; Bird, R.; Biteau, J.; Bouvier, A.; Bugaev, V.; Cardenzana, J. V.; Cerruti, M.; Chen, X.; Ciupik, L.; Connolly, M. P.; Cui, W.; Dickinson, H. J.; Dumm, J.; Eisch, J. D.; Errando, M.; Falcone, A.; Feng, Q.; Finley, J. P.; Fleischhack, H.; Fortin, P.; Fortson, L.; Furniss, A.; Gillanders, G. H.; Griffin, S.; Griffiths, S. T.; Grube, J.; Gyuk, G.; Håkansson, N.; Hanna, D.; Holder, J.; Humensky, T. B.; Johnson, C. A.; Kaaret, P.; Kar, P.; Kertzman, M.; Khassen, Y.; Kieda, D.; Krause, M.; Krennrich, F.; Kumar, S.; Lang, M. J.; Maier, G.; McArthur, S.; McCann, A.; Meagher, K.; Millis, J.; Moriarty, P.; Mukherjee, R.; Nieto, D.; O'Faoláin de Bhróithe, A.; Ong, R. A.; Otte, A. N.; Park, N.; Pohl, M.; Popkow, A.; Prokoph, H.; Pueschel, E.; Quinn, J.; Ragan, K.; Reyes, L. C.; Reynolds, P. T.; Richards, G. T.; Roache, E.; Santander, M.; Sembroski, G. H.; Shahinyan, K.; Smith, A. W.; Staszak, D.; Telezhinsky, I.; Tucci, J. V.; Tyler, J.; Varlotta, A.; Vincent, S.; Wakely, S. P.; Weinstein, A.; Welsing, R.; Wilhelm, A.; Williams, D. A.; Zitzer, B.; Veritas Collaboration; Hughes, Z. D.

    2015-08-01

    During moonlit nights, observations with ground-based Cherenkov telescopes at very high energies (VHEs, E\\gt 100 GeV) are constrained since the photomultiplier tubes (PMTs) in the telescope camera are extremely sensitive to the background moonlight. Observations with the VERITAS telescopes in the standard configuration are performed only with a moon illumination less than 35% of full moon. Since 2012, the VERITAS collaboration has implemented a new observing mode under bright moonlight, by either reducing the voltage applied to the PMTs (reduced-high-voltage; RHV configuration), or by utilizing UV-transparent filters. While these operating modes result in lower sensitivity and increased energy thresholds, the extension of the available observing time is useful for monitoring variable sources such as blazars and sources requiring spectral measurements at the highest energies. In this paper we report the detection of γ-ray flaring activity from the BL Lac object 1ES 1727+502 during RHV observations. This detection represents the first evidence of VHE variability from this blazar. The integral flux is (1.1+/- 0.2)× {10}-11 {{cm}}-2 {{{s}}}-1 above 250 GeV, which is about five times higher than the low-flux state. The detection triggered additional VERITAS observations during standard dark-time. Multiwavelength observations with the FLWO 48″ telescope, and the Swift and Fermi satellites are presented and used to produce the first spectral energy distribution (SED) of this object during γ-ray flaring activity. The SED is then fitted with a standard synchrotron-self-Compton model, placing constraints on the properties of the emitting region and of the acceleration mechanism at the origin of the relativistic particle population in the jet.

  16. Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524

    CERN Document Server

    Aliu, E; Bautista, M; Beilicke, M; Benbow, W; Böttcher, M; Bradbury, S M; Buckley, J H; Bugaev, V; Butt, Y; Byrum, K; Cannon, A; Celik, O; Cesarini, A; Chow, Y C; Ciupik, L; Cogan, P; Colin, P; Cui, W; Dickherber, R; Duke, C; Ergin, T; Falcone, A; Fegan, S J; Finley, J P; Finnegan, G; Fortin, P; Fortson, L; Furniss, A; Gall, D; Gibbs, K; Gillanders, G H; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Hays, E; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, Philip; Karlsson, N; Kertzman, M; Kieda, D; Kildea, J; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Maier, G; McCann, A; McCutcheon, M; Millis, J; Moriarty, P; Mukherjee, R; Nagai, T; Ong, R A; Otte, A N; Pandel, D; Perkins, J S; Petry, D; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Roache, E; Rose, J; Schroedter, M; Sembroski, G H; Smith, A W; Steele, D; Swordy, S P; Theiling, M; Toner, J A; Valcarcel, L; Varlotta, A; Vasilev, V V; Wagner, R G; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; White, R J; Williams, D A; Wissel, S; Wood, M; Zitzer, B

    2008-01-01

    The high-frequency-peaked BL-Lacertae object \\objectname{1ES 0806+524}, at redshift z=0.138, was observed in the very-high-energy (VHE) gamma-ray regime by VERITAS between November 2006 and April 2008. These data encompass the two-, and three-telescope commissioning phases, as well as observations with the full four-telescope array. \\objectname{1ES 0806+524} is detected with a statistical significance of 6.3 standard deviations from 245 excess events. Little or no measurable variability on monthly time scales is found. The photon spectrum for the period November 2007 to April 2008 can be characterized by a power law with photon index $3.6 \\pm 1.0_{\\mathrm{stat}} \\pm 0.3_{\\mathrm{sys}}$ between $\\sim$300 GeV and $\\sim$700 GeV. The integral flux above 300 GeV is $(2.2\\pm0.5_{\\mathrm{stat}}\\pm0.4_{\\mathrm{sys}})\\times10^{-12}\\:\\mathrm{cm}^{2}\\:\\mathrm{s}^{-1}$ which corresponds to 1.8% of the Crab Nebula flux. Non contemporaneous multiwavelength observations are combined with the VHE data to produce a broadband ...

  17. Detection of Possible Quasi-periodic Oscillations in the Long-term Optical Light Curve of the BL Lac Object OJ 287

    CERN Document Server

    Bhatta, G; Stawarz, Ł; Ostrowski, M; Winiarski, M; Ogłoza, W; Dróżdz, M; Siwak, M; Liakos, A; Kozieł-Wierzbowska, D; Gazeas, K; Debski, B; Kundera, T; Stachowski, G; Paliya, V S

    2016-01-01

    Detection of periodicity in the broad-band non-thermal emission of blazars has so far been proven to be elusive. However, there are a number of scenarios which could lead to quasi-periodic variations in blazar light curves. For example, orbital or thermal/viscous period of accreting matter around central supermassive black holes could, in principle, be imprinted in the multi-wavelength emission of small-scale blazar jets, carrying as such crucial information about plasma conditions within the jet launching regions. In this paper, we present the results of our time series analysis of $\\sim 9.2$ year-long, and exceptionally well-sampled optical light curve of the BL Lac OJ 287. The study primarily uses the data from our own observations performed at the Mt. Suhora and Krak\\'ow Observatories in Poland, and at the Athens Observatory in Greece. Additionally, SMARTS observations were used to fill in some of the gaps in the data. The Lomb-Scargle Periodogram and the Weighted Wavelet Z-transform methods were employed...

  18. Observations of low and intermediate-frequency-peaked BL Lacs above 100 GeV with VERITAS

    Directory of Open Access Journals (Sweden)

    Errando M.

    2013-12-01

    Full Text Available Most of the ~ 50 blazars detected to date at TeV energies (E > 0.1 TeV are high-frequency-peaked BL Lacs (HBLs. Only a handful episodic detections of low- and intermediate-frequency-peaked BL Lacs (LBL/IBLs, with synchrotron peak frequencies in the infrared and optical regime have been reported by ground-based gamma-ray telescopes, typically during high-flux states. The VERITAS array located in southern Arizona has observed five known TeV LBL/IBLs since 2009: 3C 66A, WComae, PKS 1424+240, S5 0716+714 and BL Lacertae, with exposures of 5-10 hours/year, which so far resulted in the detection of a bright, sub-hour timescale gamma-ray flare of BL Lacertae in June 2011. We also report the detection and characterization of two new IBLs: VER J0521+211 and B2 1215+30.

  19. Observations of low- and intermediate-frequency-peaked BL Lacs above 100 GeV with VERITAS

    CERN Document Server

    Errando, M

    2013-01-01

    Most of the ~50 blazars detected to date at TeV energies (E>0.1 TeV) are high-frequency-peaked BL Lacs (HBLs). Only a handful episodic TeV detections of low- and intermediate-frequency-peaked BL Lacs (LBL/IBLs, with synchrotron peak frequencies in the infrared and optical regime) have been reported, typically during high-flux states. The VERITAS array, a ground-based TeV observatory located in southern Arizona has observed five known TeV LBL/IBLs since 2009: 3C 66A, W Comae, PKS 1424+240, S5 0716+714 and BL Lacertae, with at least 5-10 hours/year, which so far resulted in the detection of a bright, sub-hour timescale gamma-ray flare of BL Lacertae in June 2011. We also report the detection and characterization of two new IBLs: VER J0521+211 and B2 1215+30.

  20. Multi-Epoch VLBA Observations of EGRET-Detected Quasars and BL Lac Objects Connection between Superluminal Ejections and Gamma-Ray Flares in Blazars

    CERN Document Server

    Jorstad, S G; Mattox, J R; Aller, M F; Aller, H D; Wehrle, A E; Bloom, S D; Jorstad, Svetlana G; Marscher, Alan P; Mattox, John R; Aller, Margo F; Aller, Hugh D; Wehrle, Ann E; Bloom, Steven D

    2001-01-01

    We examine the coincidence of times of high $\\gamma$-ray flux and ejections of superluminal components from the core in EGRET blazars based on a VLBA monitoring program at 22 and 43 GHz from November 1993 to July 1997. In 23 cases of $\\gamma$-ray flares for which sufficient VLBA data exist, 16 of the flares (in 14 objects) fall within 3$\\sigma$ and 9 of these within 1$\\sigma$ uncertainties of the extrapolated epoch of zero separation from the core of a superluminal radio component. In each of two sources (0528+134 and 1730-130) two successive $\\gamma$-ray flares were followed by the appearance of new superluminal components. We carried out statistical simulations which show that if the number of coincidences $\\ge$ 7 the radio and $\\gamma$-ray events are associated with each other at >99.999% confidence. Our analysis of the observed behavior, including variability of the polarized radio flux, of the sources before, during, and after the $\\gamma$-ray flares suggests that the $\\gamma$-ray events occur in the sup...

  1. [The orbitotemporal region in the cranium of Chelydra serpentina Linnaeus (Chelonia) and Lacerta sicula Rafinesque (Lacertilia)].

    Science.gov (United States)

    Rieppel, O

    1976-01-01

    An analysis of the ontogenesis of the chondrocranium gives the following homologies in the skull of Lacerta and Chelydra: (see article). It is shown that the extracranial position of the cavum epiptericum in Lacerta corresponds to the stage of maximal development of the chondrocranium in Chelydra. But further development brings about a dermal sidewall in the orbitotemporal region, b,ilt up by descending parietal flanges which incorporate the epipterygoid. This not only allows the pila antotica to degenerate but also incorporates the cavum in the cranial cavity.

  2. BL LAC candidates for TeV observations

    Energy Technology Data Exchange (ETDEWEB)

    Massaro, F.; Paggi, A.; Errando, M.; D' Abrusco, R.; Masetti, N.; Tosti, G.; Funk, S.

    2013-07-01

    BL Lac objects are the most numerous class of extragalactic TeV-detected sources. One of the biggest difficulties in investigating their TeV emission is due to their limited number, since only 47 BL Lac objects are known to be TeV emitters. In this paper, we propose new criteria to select TeV BL Lac candidates based on infrared and X-ray observations. We apply our selection criteria to the BL Lac objects listed in the ROMA-BZCAT catalog, thereby identifying 41 potential TeV emitters. We then perform a search over a more extended sample combining the ROSAT bright source catalog and the WISE all-sky survey, revealing 54 additional candidates for TeV observations. Our investigation also led to a tentative classification of 16 unidentified X-ray sources as BL Lac candidates. This analysis provides new interesting BL Lac targets for future observations with ground-based Cherenkov telescopes.

  3. The Multi-periodic Blazhko Modulation of CZ Lacertae

    CERN Document Server

    Sódor, Á; Szeidl, B; Váradi, M; Henden, A; Vida, K; Hurta, Zs; Posztobányi, K; Dékány, I; Szing, A

    2010-01-01

    Thorough analysis of the multicolour CCD observations of the RRab-type variable, CZ Lacertae is presented. The observations were carried out in two consecutive observing seasons in 2004 and 2005 within the framework of the Konkoly Blazhko Survey of bright, northern, short-period RRab variables. The O-C variation of CZ Lac indicated that a significant period decrease took place just around the time of the CCD observations. Our data gave a unique opportunity to study the related changes in the pulsation and modulation properties of a Blazhko star in detail. Two different period components ($\\approx$14.6 d and $\\approx$18.6 d) of the Blazhko modulation were identified. Both modulation components had similar strength. The periods and amplitudes of the modulations changed significantly from the first season to the next, meanwhile, the mean pulsation amplitude slightly decreased. The modulation frequencies were in a 5:4 resonance ratio in the first observing season then the frequencies shifted in opposite direction...

  4. Phylogeography and demographic history of Lacerta lepida in the Iberian Peninsula

    DEFF Research Database (Denmark)

    Miraldo, Andreia; Hewitt, Godfrey M; Paulo, Octavio S;

    2011-01-01

    either on species with narrow distributions within the region or species groups that, although widely distributed, generally have a genetic structure that relates to pre-Quaternary cladogenetic events. In this study we undertake a detailed phylogeographic analysis of the lizard species, Lacerta lepida...

  5. The RGB Sample of Intermediate BL Lacs

    CERN Document Server

    Laurent-Mühleisen, S A; Feigelson, E D; Brinkmann, W; Siebert, J

    1999-01-01

    Combining newly identified and previously known BL Lacs from the RASS-Green Bank (RGB) catalog, we present a sample of 127 BL Lacs, the largest ever derived from a single uniform survey. A Complete sample of 33 objects brighter than O=18.0 mag is also presented. These samples are compared to other known BL Lac samples and are generally found to exhibit properties intermediate between those of the previously disparate classes of High and Low energy peaked BL Lacs (HBLs and LBLs, respectively). This result is most dramatic in the distribution of the X-ray to radio logarithmic flux ratios, where the RGB BL Lacs are shown to peak precisely where the sharp dichotomy between the two subclasses was previously seen. The alpha_ro vs alpha_ox diagram also shows the RGB sample smoothly bridges the gap between the previously distinct subclasses of LBLs and HBLs. We also find a weak, but statistically significant correlation between the composite X-ray spectral index alpha_xox and alpha_ro. This implies that the more LBL-...

  6. The Discovery of Low-Luminosity BL Lacs

    Science.gov (United States)

    Rector, Travis A.; Stocke, John T.

    1995-12-01

    Many of the properties of BL Lacs have become explicable in terms of the ``relativistic beaming'' hypothesis whereby BL Lacs are ``highly beamed'' FR-I radio galaxies (i.e. our line of sight to these objects is nearly along the jet axis). Further, radio-selected BL Lacs (RBLs) are believed to be seen nearly ``on-axis'' (the line-of-sight angle theta ~ 8deg ) while X-ray selected BL Lacs (XBLs) are seen at larger angles (theta ~ 30deg ; the X-ray emitting jet is believed to be less collimated). However, a major problem with this model was that a transition population between beamed BL Lacs and unbeamed FR-Is had not been detected. Low-luminosity BL Lacs may be such a transition population, and were predicted to exist by Browne and Marcha (1993). We present ROSAT HRI images, VLA radio maps and optical spectra which confirm the existence of low-luminosity BL Lacs, objects which were previously mis-identified in the EMSS catalog as clusters of galaxies. Thus our results strengthen the relativistic beaming hypothesis.

  7. Association of Mc1r variants with ecologically relevant phenotypes in the European ocellated lizard, Lacerta lepida

    DEFF Research Database (Denmark)

    Nunes, V. L.; Miraldo, A.; Beaumont, M. A.;

    2011-01-01

    range of vertebrate taxa, was assessed in European ocellated lizards (Lacerta lepida) to search for associations with melanin-based colour phenotypes. Lacerta lepida subspecies' distribution is associated with the three major bio-climatic regions in the Iberian Peninsula. A nonconserved and derived....... l. iberica. Extensive genotyping of Mc1r along the contact zone between L. l. nevadensis and L. l. lepida revealed low gene flow (only two hybrids detected). The implications of these findings are discussed in the context of previous knowledge about the evolutionary history of ocellated lizards....

  8. Blütenvielfalt auf dem Acker

    OpenAIRE

    Petersen, B.M.

    2011-01-01

    Früher zierten zahlreiche Blüten die Äcker. Heute sind die Äcker weitgehend blütenarm. Damit fehlt den Blütenbesuchern die Nahrungsquelle und den Landwirten die Blütenbestäuber. Blütenvielfalt bietet darüber hinaus noch viele weitere Vorteile - auch für den Landwirt. Das Merkblatt will Mut machen, wieder mehr Blüten- und Artenvielfalt auf den Acker zu bringen. Es liefert dem Landwirt dazu viele Ideen und Entscheidungshilfen.

  9. Den Blå Drage

    DEFF Research Database (Denmark)

    Ingerslev, Gitte Holten

    Denne publikation i serien Læselyst tjener tre formål. Den evaluerer læseprojektet Den blå drage i efteråret 2004 på Byskolen i Svendborg ? et projekt ledet af forfatteren Josefine Ottesen. Desuden gøres der rede for nogle af de teorier der støtter og begrunder arbejdsmåde og resultater i projektet...

  10. IDV Observations of BL0716+714 at 5 GHz

    Indian Academy of Sciences (India)

    H.-G Song; X. Liu; J. Liu; N. Marchili; T. P. Krichbaum

    2011-03-01

    A selected sample of intra-day variable AGN had been observed for 3–4 days per month at the Urumqi Observatory. The sample includes 7 target sources and 7 calibrators. The BL Lac object B0716+714 shows prominent intraday and long term variations.

  11. Flat radio-spectrum galaxies and BL Lacs I. Core properties

    NARCIS (Netherlands)

    Dennett-Thorpe, J; Marcha, MJ

    2000-01-01

    This paper concerns the relationship of BL Lacs and flat-spectrum weak emission-line galaxies. We compare the weak emission-line galaxies and the BL Lacs in a sample of 57 flat-spectrum objects (Marcha et al. 1996), using high-frequency radio and non-thermal optical flux densities, spectral indices

  12. Unbroken B-L Symmetry

    CERN Document Server

    Heeck, Julian

    2014-01-01

    The difference between baryon number B and lepton number L is the only anomaly-free global symmetry of the Standard Model, easily promoted to a local symmetry by introducing three right-handed neutrinos, which automatically make neutrinos massive. The non-observation of any (B-L)-violating processes leads us to scrutinize the case of unbroken gauged B-L; besides Dirac neutrinos, the model contains only three parameters, the gauge coupling strength g', the Stueckelberg mass $M_{Z'}$, and the kinetic mixing angle $\\chi$. The new force could manifest itself at any scale, and we collect and derive bounds on g' over the entire testable range $M_{Z'}$ = 0 - $10^{13}$ eV, also of interest for the more popular case of spontaneously broken B-L or other new light forces. We show in particular that successful Big Bang nucleosynthesis provides strong bounds for masses 10 eV < $M_{Z'}$ < 10 GeV due to resonant enhancement of the rate $\\overline{f} f \\leftrightarrow \\overline{\

  13. Infrared Polarization and Beaming Effect for BL Lac Objects

    Institute of Scientific and Technical Information of China (English)

    MEI Dong-Cheng; XIE Guang-Zhong

    2001-01-01

    With the idea of the beaming models, we derive a relation between the observed polarization and Dopplercorrected magnitude; that is, the observed polarization is in anti-correlation with the Doppler-corrected magnitude. Making use of the infrared data observed simultaneously by Impey et al. [Mon. Not. R. Astron. Soc.200 (1982) 19; 209 (1984) 245] and Holmes et al. [ibid. 210 (1984) 961] we found that: (1) there is a significant correlation between the observed maximum polarization and Doppler-corrected magnitude but the polarization is not in anti-correlation with the Doppler-corrected magnitude; (2) the maximum infrared polarization is strongly correlated with the maximum optical polarization. Our conclusion is that the infrared polarization depends only on the degree of ordering of the magnetic field in the synchrotron emission regions and not on the beaming effect.Both infrared and optical emissions originate from the synchrotron radiation.

  14. The importance of habitat resistance for movement decisions in the common lizard, Lacerta vivipara

    Directory of Open Access Journals (Sweden)

    Zajitschek Susanne RK

    2012-07-01

    Full Text Available Abstract Background Movement behaviour can be influenced by a multitude of biotic and abiotic factors. Here, we investigate the speed of movement in relation to environmental and individual phenotypic properties in subadult common lizards (Lacerta vivipara. We aim to disentangle the importance of substrate, cover, humidity, basking opportunity and individual phenotype on moving tendencies in 12 treatment combinations, at which each lizard was tested. Results We find that movement behaviour depends on the starting conditions, the physical properties of the dispersal corridor, and on the individuals’ phenotype. Specifically, the presence of cover and substrate providing suitable traction in the corridor had positive effects on individual movement decisions. Additionally, we find high phenotypic variation in the propensity to move dependent on the presence of cover. Individual back patterns also strongly affected movement decisions in interaction with the physical properties of the dispersal corridor. Conclusions Our results highlight the importance of understanding the habitat resistance for movement patterns, with humid habitats with covering vegetation providing the best conditions to initiate movement in the common lizard. In addition, population effects, differences in back pattern phenotype and individual plasticity were identified as key parameters influencing movement behaviour.

  15. Ultraviolet nuptial colour determines fight success in male European green lizards (Lacerta viridis).

    Science.gov (United States)

    Bajer, Katalin; Molnár, Orsolya; Török, János; Herczeg, Gábor

    2011-12-23

    Animal communication through colour signals is a central theme in sexual selection. Structural colours can be just as costly and honest signals as pigment-based colours. Ultraviolet (UV) is a structural colour that can be important both in intrasexual competition and mate choice. However, it is still unknown if a UV signal alone can determine the outcome of male-male fights. European green lizard (Lacerta viridis) males develop a nuptial throat coloration with a strong UV component. Among males differing only in their manipulated UV colour, females prefer males with higher UV. Here, we experimentally decreased the UV coloration of randomly chosen males from otherwise similar male pairs to test the hypothesis that a difference in UV colour alone can affect fight success during male-male competition. Our results fully supported the hypotheses: in almost 90 per cent of the contests the male with reduced UV lost the fight. Our results show that UV can be an important signal, affecting both female mate choice and determining male fight success.

  16. UV-deprived coloration reduces success in mate acquisition in male sand lizards (Lacerta agilis.

    Directory of Open Access Journals (Sweden)

    Mats Olsson

    Full Text Available BACKGROUND: Recent work on animal signals has revealed a wide occurrence of UV signals in tetrapods, in particular birds, but also in lizards (and perhaps other Squamate reptiles. Our previous work on the Swedish sand lizard (Lacerta agilis has verified, both in correlative selection analyses in the wild and with laboratory and field experiments, the importance of the green 'badge' on the body sides of adult males for securing mating opportunities, probably mostly through deterring rival males rather than attracting females. The role of UV in communication has, however, never been examined. METHODOLOGY/PRINCIPAL FINDINGS: Here we show that when measured immediately after spring skin shedding, there is also signaling in the UV. By UV-depriving the signal (reflectance with sun block chemicals fixated with permeable, harmless spray dressing, we show that males in the control group (spray dressing only had significantly higher success in mate acquisition than UV-deprived males. CONCLUSIONS/SIGNIFICANCE: These results suggest that at least two colour traits in sand lizards, badge area and UV, contribute to rival deterrence and/or female choice on UV characters, which elevates success in mate acquisition in UV intact male sand lizards.

  17. The REX survey as a Tool to Test the Beaming Model for BL Lacs

    Science.gov (United States)

    Caccianiga, A.; della Ceca, R.; Gioia, I. M.; Maccacaro, T.; Wolter, A.

    We present the preliminary properties of the BL Lacs discovered in the REX survey (Caccianiga et al. 1998). In particular, we discuss a few sources with optical spectral properties ``intermediate'' between those of BL Lacs and those of elliptical galaxies. These objects could harbour weak (in the optical band) sources of non-thermal continuum in their nuclei and, if confirmed, they could represent the faint tail of the BL Lac population. The existence of such ``weak'' BL Lacs is matter of discussion in recent literature (e.g. Marcha et al. 1996) and could lead to a revision of the defining criteria of a BL Lac and, consequently, of their cosmological and statistical properties.

  18. Blødningsforstyrrelser hos kvinder

    DEFF Research Database (Denmark)

    Astrup, Karen

    1994-01-01

    Efteruddannelsesartikel for praktiserende læger om undersøgelse og behandling af blødningsforstyrrelser hos kvinder i almen praksis. Udgivelsesdato: 1994......Efteruddannelsesartikel for praktiserende læger om undersøgelse og behandling af blødningsforstyrrelser hos kvinder i almen praksis. Udgivelsesdato: 1994...

  19. [Ultrastructure of the "rudimentary secretory photoreceptors" (RSP) of the embryonic pineal body of Lacerta vivipara J. (Reptilia, Lacertilia) and the origin of the RSP of Sauropsida].

    Science.gov (United States)

    Meiniel, A

    1975-10-20

    The "secretory rudimentary photoreceptor-cells" of Lacerta vivipara J., during embryonic stages, exhibit photosensory differentiations (disks). Our ontogenetic observations agree with the phylogenetic studies and support the concept of a "sensory cell line" (Colin, 1969) in the pineal organ of vertebrates.

  20. Sédentarité, déplacements et répartition des individus dans une population de Lacerta viridis (Laurenti, 1768) (Lacertilia, Lacertidae)

    NARCIS (Netherlands)

    Girons, Saint H.; Bradshaw, S.D.

    1989-01-01

    A mark-and-recapture study was undertaken in August 1983, May and September 1987, and May 1988 of a small discrete population of Lacerta viridis occupying an area of 260 x 11—25 m, along the length of a canal in western France. A total of 21 recaptures, over periods of time varying from four months

  1. Mating order-dependent female mate choice in the polygynandrous common lizard Lacerta vivipara.

    Science.gov (United States)

    Fitze, Patrick S; Cote, Julien; Clobert, Jean

    2010-02-01

    Recent studies indicate that directional female mate choice and order-dependent female mate choice importantly contribute to non-random mating patterns. In species where females prefer larger sized males, disentangling different hypotheses leading to non-random mating patterns is especially difficult, given that male size usually correlates with behaviours that may lead to non-random mating (e.g. size-dependent emergence from hibernation, male fighting ability). Here we investigate female mate choice and order-dependent female mate choice in the polygynandrous common lizard (Lacerta vivipara). By sequentially presenting males in random order to females, we exclude non-random mating patterns potentially arising due to intra-sexual selection (e.g. male-male competition), trait-dependent encounter probabilities, trait-dependent conspicuousness, or trait-dependent emergence from hibernation. To test for order-dependent female mate choice we investigate whether the previous mating history affects female choice. We show that body size and body condition of the male with which a female mated for the first time were bigger and better, respectively, than the average body size and body condition of the rejected males. There was a negative correlation between body sizes of first and second copulating males. This indicates that female mate choice is dependent on the previous mating history and it shows that the female's choice criteria are non-static, i.e. non-directional. Our study therefore suggests that context-dependent female mate choice may not only arise due to genotype-environment interactions, but also due to other female mating strategies, i.e. order-dependent mate choice. Thus context-dependent female mate choice might be more frequent than previously thought.

  2. GENERALIZED FUZZY FILTERS OF BL-ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    The concept of quasi-coincidence of a fuzzy interval value with an interval valued fuzzy set is considered. In fact, this is a generalization of quasi-coincidence of a fuzzy point with a fuzzy set. By using this new idea, the notion of interval valued (∈, ∈∨q)-fuzzy filters in BL-algebras which is a generalization of fuzzy filters of BL-algebras, is defined, and related properties are investigated. In particular, the concept of a fuzzy subgroup with thresholds is extended to the concept of an interval valued fuzzy filter with thresholds in BL-algebras.

  3. Varicus lacerta, a new species of goby (Teleostei, Gobiidae, Gobiosomatini, Nes subgroup) from a mesophotic reef in the southern Caribbean.

    Science.gov (United States)

    Tornabene, Luke; Robertson, D Ross; Baldwin, Carole C

    2016-01-01

    We describe a new species of goby, Varicus lacerta sp. n., which was collected from a mesophotic reef at Curacao, southern Caribbean. The new species is the tenth species of Varicus, all of which occur below traditional SCUBA depths in the wider Caribbean area. Its placement in the genus Varicus is supported by a molecular phylogenetic analysis of three nuclear genes and the mitochondrial gene cytochrome b. In addition, the new species has one anal-fin pterygiophore inserted anterior to the first haemal spine, which distinguishes Varicus species from most species in the closely related and morphologically similar genus Psilotris. Varicus lacerta sp. n. is distinguished from all other named species of Varicus by the absence of scales, having highly branched, feather-like pelvic-fin rays, and in its live coloration. We provide the cytochrome c oxidase I DNA barcode of the holotype and compare color patterns of all species of Varicus and Psilotris for which color photographs or illustrations are available. This study is one of several recent studies demonstrating the utility of manned submersibles in exploring the diversity of poorly studied but species-rich deep-reef habitats.

  4. On the magnetization of BL Lac jets

    CERN Document Server

    Tavecchio, F

    2015-01-01

    The current paradigm foresees that relativistic jets are launched as magnetically dominated flows, whose magnetic power is progressively converted to kinetic power of of the matter of the jet, until equipartition is reached. Therefore, at the end of the acceleration phase, the jet should still carry a substantial fraction ($\\approx$ half) of its power in the form of a Poynting flux. It has been also argued that, in these conditions, the best candidate particle acceleration mechanism is efficient reconnection of magnetic field lines, for which it is predicted that magnetic field and accelerated relativistic electron energy densities are in equipartition.Through the modeling of the jet non--thermal emission, we explore if equipartition is indeed possible in BL Lac objects, i.e. low-power blazars with weak or absent broad emission lines. We find that one-zone models (for which only one region is involved in the production of the radiation we observe) the particle energy density is largely dominating (by 1-2 orde...

  5. New results from the HRX BL Lac sample

    CERN Document Server

    Beckmann, V; Beckmann, Volker; Wolter, Anna

    2000-01-01

    We present results for the Hamburg BL Lac sample, based on data provided by the RASS-BSC. By fitting a single power law to the X-ray data we find, in a number of objects, an additional absorbing component to the galactic value of NH, which might be attributed to intrinsic absorption. A more probable cause seems however to be a curvature in the X-ray spectra in the sense that they are more curved for steeper slopes. The known relation between the X-ray spectral slope and the ratio between optical and X-ray flux alpha_ox also applies to this BL Lac sample, even though less significant than in previous works. We also find a dependence of X-ray luminosity on alpha_ox.

  6. Galactic membership of BL Her type variable stars

    CERN Document Server

    Jurkovic, Monika I; Ninković, Slobodan

    2016-01-01

    As the RR Lyrae stars evolve on the Hertzsprung-Russell diagram they are believed to become short period Type II Cepheids, known as BL Her type (with a pulsation period from $1$ to $3-8$ days). Assuming that their mass is around $0.5 - 0.6 {\\rm M}_{\\odot}$, and that they are low metallicity objects, they were thought to belong to the halo of the Milky Way. We investigated seven Galactic short period Type II Cepheids (BL Her, SW Tau, V553 Cen, DQ And, BD Cas, V383 Cyg, and KT Com) in order to establish their membership within the Galactic structure using the kinematic approach. $Gaia$ should provide us with more data needed to conduct the study of the whole sample.

  7. Galactic membership of BL Her type variable stars

    Science.gov (United States)

    Jurkovic, M. I.; Stojanovic, M.; Ninkovic, S.

    2016-05-01

    As the RR Lyrae stars evolve on the Hertzsprung-Russell diagram they are believed to become short period Type II Cepheids, known as BL Her type (with a pulsation period from 1 to 3-8 days). Assuming that their mass is around 0.5-0.6M_Sol, and that they are low metallicity objects, they were thought to belong to the halo of the Milky Way. We investigated seven Galactic short period Type II Cepheids (BL Her, SW Tau, V553 Cen, DQ And, BD Cas, V383 Cyg, and KT Com) in order to establish their membership within the Galactic structure using the kinematic approach. Gaia should provide us with more data needed to conduct the study of the whole sample.

  8. The CLASS BL Lac sample: The Radio Luminosity Function

    CERN Document Server

    Marcha, M J M

    2013-01-01

    This paper presents a new sample of BL Lac objects selected from a deep (30 mJy) radio survey of flat spectrum radio sources (the CLASS blazar survey, henceforth CBS). The sample is one of the largest well defined samples in the low power regime with a total of 130 sources of which 55 satisfy the 'classical' optical BL Lac selection criteria, and the rest have indistinguishable radio properties. The primary goal of this study is to establish the Radio Luminosity Function (RLF) on firm statistical ground at low radio luminosities where previous samples have not been able to investigate. The gain of taking a peek at lower powers is the possibility to search for the flattening of the LF which is a feature predicted by the beaming model but which has remained elusive to observational confirmation. In this study we extend for the first time the BL Lac RLF down to very low radio powers ~10^22 W/Hz, ie, two orders of magnitude below the RLF currently available in the literature. In the process we confirm the importa...

  9. Asteroseismology of the Beta Cephei star 12 (DD) Lacertae: photometric observations, pulsational frequency analysis and mode identification

    CERN Document Server

    Handler, G; Rodríguez, E; Uytterhoeven, K; Amado, P J; Dorokhova, T N; Dorokhov, N I; Poretti, E; Sareyan, J P; Parrao, L; Lorenz, D; Zsuffa, D; Drummond, R; Daszynska-Daszkiewicz, J; Verhoelst, T; De Ridder, J; Acke, B; Bourge, P O; Movchan, A I; Garrido, R; Paparo, M; Sahin, T; Antoci, V; Udovichenko, S N; Csorba, K; Crowe, R; Berkey, B; Stewart, S; Terry, D; Mkrtichian, D E; Aerts, C

    2006-01-01

    We report a multisite photometric campaign for the Beta Cephei star 12 Lacertae. 750 hours of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with 9 telescopes during 190 nights. Our frequency analysis results in the detection of 23 sinusoidal signals in the light curves. Eleven of those correspond to independent pulsation modes, and the remainder are combination frequencies. We find some slow aperiodic variability such as that seemingly present in several Beta Cephei stars. We perform mode identification from our colour photometry, derive the spherical degree l for the five strongest modes unambiguously and provide constraints on l for the weaker modes. We find a mixture of modes of 0 <= l <= 4. In particular, we prove that the previously suspected rotationally split triplet within the modes of 12 Lac consists of modes of different l; their equal frequency splitting must thus be accidental. One of the periodic signals we detected in the light c...

  10. [Increased variability of (TCC)n microsatelline loci in populations of the parthenogenetic lizard Lacerta unisexualis Darevsky].

    Science.gov (United States)

    Ryskov, A P; Kan, N G; Martirosian, I A; Darevskiĭ, I S; Danielian, F D; Petrosian, V G; Tokarskaia, O N

    2000-11-01

    In four isolated populations of parthenogenetic Caucasian rock lizard Lacerta unisexualis, variability of (TCC)n loci was examined using multilocus DNA fingerprinting. Unexpectedly high variability of (TCC)n microsatellites was found in all four populations. The mean similarity index was 0.825, which is higher than similarity estimates obtained for other mini- and microsatellite loci in L. unisexualis and parthenogenetic species L. dahli and L. armeniaca studied earlier. The high variation level of (TCC)n loci was shown to be at least partially associated with the presence of a diverged (TCC)n sequence fraction in the L. unisexualis genome. Mutations at some other genetically unstable (TCC)n loci may cause their structural diversity in populations of L. unisexualis.

  11. Numts help to reconstruct the demographic history of the ocellated lizard (Lacerta lepida) in a secondary contact zone

    DEFF Research Database (Denmark)

    Miraldo, Andreia; Hewitt, Godfrey M; Dear, Paul H

    2012-01-01

    In northwestern Iberia, two largely allopatric Lacerta lepida mitochondrial lineages occur, L5 occurring to the south of Douro River and L3 to the north, with a zone of putative secondary contact in the region of the Douro River valley. Cytochrome b sequence chromatograms with polymorphisms...... of secondary contact between the lineages. The additional incidence of these numts to the north of the putative contact zone is consistent with an earlier postglacial northward range expansion of L5, preceding that of L3. We show that genetic exchange between the lineages responsible for the origin...... of these numts in L3 after secondary contact occurred prior to, or coincident with, the northward expansion of L3. This study shows that, in the context of phylogeographic analysis, numts can provide evidence for past demographic events and can be useful tools for the reconstruction of complex evolutionary...

  12. Chaos in hydrodynamic BL Herculis models

    CERN Document Server

    Smolec, R

    2014-01-01

    We present non-linear, convective, BL Her-type hydrodynamic models that show complex variability characteristic for deterministic chaos. The bifurcation diagram reveals a rich structure, with many phenomena detected for the first time in hydrodynamic models of pulsating stars. The phenomena include not only period doubling cascades en route to chaos (detected in earlier studies) but also periodic windows within chaotic band, type-I and type-III intermittent behaviour, interior crisis bifurcation and others. Such phenomena are known in many textbook chaotic systems, from the simplest discrete logistic map, to more complex systems like Lorenz equations. We discuss the physical relevance of our models. Although except of period doubling such phenomena were not detected in any BL Her star, chaotic variability was claimed in several higher luminosity siblings of BL Her stars - RV Tau variables, and also in longer-period, luminous irregular pulsators. Our models may help to understand these poorly studied stars. Pa...

  13. Blå Barracuda -formidling for sjov?

    OpenAIRE

    Fjeldsted, Tobias; Tarp, Ditte Clement; Find, Ditte Vig; Lottrup, Gry; Espensen, Maia Linnea; Lilliedal, Mathilde Raad; Olsen, Rasmus; Storm, Søren

    2004-01-01

    (DK) Rapporten indeholder en undersøgelse af en 5. klasses faglige og interessemæssige udbytte, af henholdsvis indslaget Dagens Forsøg i det naturvidenskabelige tv-program Blå Barracuda, og en konstruktivistisk undervisningssituation svarende til Dagens Forsøg. Denne problemstilling løses ved en teoretisk indføring i læringsteorier og interviewteknikker, samt en analyse af Blå Barracudas formidlingsmetoder. Der udvælges to programmer, og der udføres to sideløbne praktiske forløb med 5. kla...

  14. The Radio-optical Spectra of BL Lacs and Possible Relatives

    Science.gov (United States)

    Dennett-Thorpe, J.

    I consider the suggestion that, in a complete sample of flat-spectrum radio sources with available optical spectra (Marcha et al 1996), the strong emission line objects, or those with passive elliptical spectra are close relatives of the BL Lacs. New observations at four frequencies from 8 to 43GHz are presented, together with evidence for radio variability. Combined with other radio and optical data from the literature, we are able to construct the non-thermal SEDs and use these to address the questions: are the optically passive objects potentially `unrecognised' BL Lacs (either intrinsically weak and/or hidden by starlight)? What is the relationship between the surprising number of strong emission-line objects and the BL Lacs?

  15. The hard synchrotron X-ray spectrum of the TeV BL Lac 1ES 1426+428

    CERN Document Server

    Wolter, A; Ghisellini, G; Tavecchio, F; Maraschi, L; Costamante, L; Celotti, A; Ghirlanda, G

    2007-01-01

    We have observed 1ES 1426+428 with INTEGRAL detecting it up to $\\sim$150 keV. The spectrum is hard, confirming that this source is an extreme BL Lac object, with a synchrotron component peaking, in a $\

  16. On Fuzzy Ideals of BL-Algebras

    Directory of Open Access Journals (Sweden)

    Biao Long Meng

    2014-01-01

    Full Text Available In this paper we investigate further properties of fuzzy ideals of a BL-algebra. The notions of fuzzy prime ideals, fuzzy irreducible ideals, and fuzzy Gödel ideals of a BL-algebra are introduced and their several properties are investigated. We give a procedure to generate a fuzzy ideal by a fuzzy set. We prove that every fuzzy irreducible ideal is a fuzzy prime ideal but a fuzzy prime ideal may not be a fuzzy irreducible ideal and prove that a fuzzy prime ideal ω is a fuzzy irreducible ideal if and only if ω0=1 and |Im⁡(ω|=2. We give the Krull-Stone representation theorem of fuzzy ideals in BL-algebras. Furthermore, we prove that the lattice of all fuzzy ideals of a BL-algebra is a complete distributive lattice. Finally, it is proved that every fuzzy Boolean ideal is a fuzzy Gödel ideal, but the converse implication is not true.

  17. Blöte and Nienhuis reply

    NARCIS (Netherlands)

    Blöte, H.W.; Nienhuis, B.

    1994-01-01

    A reply to the comment by Jané Kondev and Christopher L. Henley, Conformal Charge and Exact Exponents in the n=2 Fully Packed Loop Model, Phys. Rev. Lett. 73, 2786 (1994) on Original: H. W. Blöte and B. Nienhuis, Fully packed loop model on the honeycomb lattice, Phys. Rev. Lett. 72, 1372 (1994)

  18. On annihilators in BL-algebras

    Directory of Open Access Journals (Sweden)

    Zou Yu Xi

    2016-01-01

    Full Text Available In the paper, we introduce the notion of annihilators in BL-algebras and investigate some related properties of them. We get that the ideal lattice (I(L, ⊆ is pseudo-complemented, and for any ideal I, its pseudo-complement is the annihilator I⊥ of I. Also, we define the An (L to be the set of all annihilators of L, then we have that (An(L; ⋂,∧An(L,⊥,{0}, L is a Boolean algebra. In addition, we introduce the annihilators of a nonempty subset X of L with respect to an ideal I and study some properties of them. As an application, we show that if I and J are ideals in a BL-algebra L, then JI⊥$J_I^ \\bot $ is the relative pseudo-complement of J with respect to I in the ideal lattice (I(L, ⊆. Moreover, we get some properties of the homomorphism image of annihilators, and also give the necessary and sufficient condition of the homomorphism image and the homomorphism pre-image of an annihilator to be an annihilator. Finally, we introduce the notion of α-ideal and give a notation E(I . We show that (E(I(L, ∧E, ∨E, E(0, E(L is a pseudo-complemented lattice, a complete Brouwerian lattice and an algebraic lattice, when L is a BL-chain or a finite product of BL-chains.

  19. Extreme BL Lacs: probes for cosmology and UHECR candidates

    CERN Document Server

    Tavecchio, F

    2015-01-01

    High-energy observations of extreme BL Lac objects, such as 1ES0229+200 or 1ES 0347-121, recently focused interest both for blazar and jet physics and for the implication on the extragalactic background light and intergalactic magnetic field estimate. Moreover, their enigmatic properties have been interpreted in a scenario in which their primary high- energy output is through a beam of high-energy hadrons. However, despite their possible important role in all these topics, the number of these extreme highly peaked BL Lac objects (EHBL) is still rather small. Aiming at increase their number, we selected a group of EHBL candidates considering those undetected (or only barely detected) by the LAT onboard Fermi and characterized by a high X-ray versus radio flux ratio. We assembled the multi-wavelength spectral energy distribution of the resulting 9 sources, using available archival data of Swift, GALEX, and Fermi satellites, confirming their nature. Through a simple one-zone synchrotron self-Compton model we est...

  20. Hard synchrotron BL Lacs the case of 1ES 1101-232

    CERN Document Server

    Wolter, A; Tagliaferri, G; Tavecchio, F; Caccianiga, A; Wolter, Anna; Ghisellini, Gabriele; Tagliaferri, Gianpiero; Tavecchio, Fabrizio; Caccianiga, Alessandro

    2000-01-01

    The bright X-ray selected BL Lac object 1ES1101--232 shows a flat X-ray spectrum, making it detectable with high statistics over the wide BeppoSAX energy range. We have observed it in two different epochs with BeppoSAX, and found a variation of the flux of about 30% that can be explained by a change in the spectral index above the synchrotron peak. We present here the data and infer limits on the strength of the magnetic field based on models of emission for High-frequency peaked BL Lacs.

  1. BL-代数的严格滤子%On strict filters of BL-algebras

    Institute of Scientific and Technical Information of China (English)

    杨永伟; 贺鹏飞; 李毅君

    2014-01-01

    In order to study the filter theory of BL-algebras, the concept of strict filters is introduced, and relationships between strict filters and SBL-algebra are showed. It is proved that if F is both a fantastic and strict filter of a BL-alge-bra L, then L/F is a Göodel algebra. Finally, relationships among strict filters, integral filters, prime filters and other kinds of filters are displayed.%引入了严格滤子的概念,给出了严格滤子与SBL-代数的关系,证明了若BL-代数L的滤子F是奇异的和严格的,则L/F是Gödel代数。揭示了严格滤子与整滤子、素滤子等的关系。

  2. European green lizard (Lacerta viridis) personalities: Linking behavioural types to ecologically relevant traits at different ontogenetic stages.

    Science.gov (United States)

    Bajer, Katalin; Horváth, Gergely; Molnár, Orsolya; Török, János; Garamszegi, László Zsolt; Herczeg, Gábor

    2015-02-01

    Consistent individual differences within (animal personality) and across (behavioural syndrome) behaviours became well recognized during the past decade. Nevertheless, our knowledge about the evolutionary and developmental mechanisms behind the phenomena is still incomplete. Here, we explored if risk-taking and exploration were consistent and linked to different ecologically relevant traits in wild-caught adult male European green lizards (Lacerta viridis) and in their 2-3 weeks old laboratory-reared offspring. Both adults and juveniles displayed animal personality, consistency being higher in juveniles. We found correlation between risk-taking and exploration (suggestive of a behavioural syndrome) only in adults. Juveniles were more explorative than adults. Large or ectoparasite-free adult males were more explorative than small or parasitized males. Juvenile females tended to be more risk-taking than males. Behaviour of fathers and their offspring did not correlate. We conclude that European green lizards show high behavioural consistency and age is an important determinant of its strength and links to traits likely affecting fitness.

  3. Spotted fever group rickettsiae detected in immature stages of ticks parasitizing on Iberian endemic lizard Lacerta schreiberi Bedriaga, 1878.

    Science.gov (United States)

    Kubelová, Michaela; Papoušek, Ivo; Bělohlávek, Tomáš; de Bellocq, Joëlle Goüy; Baird, Stuart J E; Široký, Pavel

    2015-09-01

    Spotted fever rickettsioses are tick-borne diseases of growing public health concern. The prevalence of rickettsia-infected ticks and their ability to parasitize humans significantly influence the risk of human infection. Altogether 466 Ixodes ricinus ticks (428 nymphs and 38 larvae) collected from 73 Lacerta schreiberi lizards were examined by PCR targeting the citrate synthetase gene gltA for the presence of Rickettsia spp. Rickettsial DNA was detected in 47% of nymphs and 31.6% of larvae. They were subsequently subjected to a second PCR reaction using primers derived from the outer membrane protein rOmpA encoding gene (ompA) to detect spotted fever group rickettsiae (SFG). This analysis shows that 41.4% of nymphs and 7.9% of larvae collected from the lizards contain DNA of SFG rickettsiae. Sequencing of 43 randomly selected samples revealed two different haplotypes, both closely related to R. monacensis (39 and 4 samples, respectively). The remaining ompA negative Rickettsia spp. samples were determined to be R. helvetica based on sequencing of ompB and gltA fragments. Our results indicate that the role of Iberian endemic lizard L. schreiberi and its ectoparasites in the ecology and epidemiology of zoonotic SFG rickettsioses may be appreciable.

  4. Iridophores and not carotenoids account for chromatic variation of carotenoid-based coloration in common lizards (Lacerta vivipara).

    Science.gov (United States)

    San-Jose, Luis M; Granado-Lorencio, Fernando; Sinervo, Barry; Fitze, Patrick S

    2013-03-01

    Abstract Carotenoids typically need reflective background components to shine. Such components, iridophores, leucophores, and keratin- and collagen-derived structures, are generally assumed to show no or little environmental variability. Here, we investigate the origin of environmentally induced variation in the carotenoid-based ventral coloration of male common lizards (Lacerta vivipara) by investigating the effects of dietary carotenoids and corticosterone on both carotenoid- and background-related reflectance. We observed a general negative chromatic change that was prevented by β-carotene supplementation. However, chromatic changes did not result from changes in carotenoid-related reflectance or skin carotenoid content but from changes in background-related reflectance that may have been mediated by vitamin A1. An in vitro experiment showed that the encountered chromatic changes most likely resulted from changes in iridophore reflectance. Our findings demonstrate that chromatic variation in carotenoid-based ornaments may not exclusively reflect differences in integumentary carotenoid content and, hence, in qualities linked to carotenoid deposition (e.g., foraging ability, immune response, or antioxidant capacity). Moreover, skin carotenoid content and carotenoid-related reflectance were related to male color polymorphism, suggesting that carotenoid-based coloration of male common lizards is a multicomponent signal, with iridophores reflecting environmental conditions and carotenoids reflecting genetically based color morphs.

  5. The gamma-ray Doppler factor determinations for a Fermi blazar sample

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Jiang-He Yang; Yi Liu; Jing-Yi Zhang

    2013-01-01

    Observations suggest that γ-ray loud blazars are strongly beamed.The Fermi mission has detected many of blazars,which provide us with a good opportunity to investigate the emission mechanism and the beaming effect in the γ-ray region.We compiled the X-ray observations for 138 Fermi blazars (54 flat spectrum radio quasars,36 low-peaked BL Lacertae objects,and 48 high-peaked BL Lacertae objects) and calculated their Doppler factors,δγ.It is interesting that the calculated Doppler factors,δγ,are strongly correlated with the γ-ray luminosity.

  6. BL LAC PKSB1144-379 an extreme scintillator

    CERN Document Server

    Turner, R J; Shabala, S S; Blanchard, J; Lovell, J E J; McCallum, J N; Cimo, G

    2012-01-01

    Rapid variability in the radio flux density of the BL Lac object PKSB1144-379 has been observed at four frequencies, ranging from 1.5 to 15 GHz, with the VLA and the University of Tasmania's Ceduna antenna. Intrinsic and line of sight effects were examined as possible causes of this variability, with interstellar scintillation best explaining the frequency dependence of the variability timescales and modulation indices. This scintillation is consistent with a compact source 20-40 microarcseconds, or 0.15-0.3 pc in size. The inferred brightness temperature for PKSB1144-379 (assuming that the observed variations are due to scintillation) is 6.2e12 K at 4.9 GHz, with approximately 10 percent of the total flux in the scintillating component. We show that scintillation surveys aimed at identifying variability timescales of days to weeks are an effective way to identify the AGN with the highest brightness temperatures.

  7. EFFECTS OF MODERATE NOISE EXPOSURE ON HEARING FUNCTION IN C57BL/6J MICE

    Institute of Scientific and Technical Information of China (English)

    SHI Chuang; SHI Lei; JIANG Xuejun; YANG Shiming; LIU Ke

    2014-01-01

    Objective To study characteristics of hearing loss after exposure to moderate noise exposure in C57BL/6J mice. Methods Male C57BL/6J mice with normal hearing at age of 5-6 weeks were chosen for this study. The mice were randomly selected to be studied immediately after exposure (Group P0), or 1 day (Group P1), 3 days (Group P3), 7 days (Group P7) or 14 days (P14) after exposure. Their before exposure condition served as the normal control. All mice were exposed to a broad-band white noise at 100 dB SPL for 2 hours, ABR thresholds were used to estimate hearing status at each time point. Results ABR threshold elevation was seen at every tested frequency at P0 (P0.05). Conclusion There is a frequency specific re-sponse to 100 dB SPL broad-band white noise in C57BL/6J mice, with the high-frequency being more susceptible. Hearing loss induced by moderate noise exposure appears reversible in C57BL/6J mice.

  8. Establishment of Germ-line Competent C57BL/6J Embryonic Stem Cell Lines

    Institute of Scientific and Technical Information of China (English)

    Gui-jun YAN; Zheng GU; Jian WANG; Jia-ke TSO

    2004-01-01

    Objective To establish C57BL/6J embryonic stem (ES) cell lines with potential germline contribution Methods ES cells were isolated from blastocyst inner cell mass of C57BL/6J mice, and cultured for 15 passages, and then injected into blastococels of lCR mice blastocysts to establish chimeric mice.Results Three ES cell lines (mC57ESl,mC57ES3, mC57ES7) derived from the inner cell mass of C57BL/6J mice blastocysts were established. They were characteristic of undifferentiated state, including normal XY karyotype, expression of a specific cell surface marker "stage-specific embryonic antigen-1" and alkaline phosphatase in continuous passage. When injected into immunodeficient mice, mC5 7ES1 cells consis tently differentiated into derivatives of all three embryonic germ layers. When mC57ES1cells were transferred into ICR mice blastocysts, 4 chimeric mice have been obtained.One male of them revealed successful germ-line transmission. Conclussion We have obtained C57BL/6J ES cell lines with a potential germ-line contribution, which can be used to generate transgenic and gene knock-out mice.

  9. Quasi-BL-Algebras and Their Equivalence with BL-Algebras%QBL-代数及其与BL-代数的等价性

    Institute of Scientific and Technical Information of China (English)

    高李红; 吴洪博

    2011-01-01

    By means of the characters that the basic logic algebra BL is matched with the fuzzy propositional logic system BL, the new logic algebraic structure called QBL-algebra has been established from the algebraizing of the axioms of fuzzy propositional logic system BL.The equivalence between the QBL-algebras and the BL-logic algebras have been proved.Consequentely, the presentative theorem of the BL-logic algebras has been given with two kinds of binary operations (×),→ on a general set.%根据命题逻辑系统BL与基础逻辑代数BL在语义方面相匹配的特征,将基础逻辑系统BL中的部分公理代数化,建立一种新的代数结构QBL-代数,并证明了QBL-代数与BL-代数的等价性,以两种二元运算(╳),→为基础在一般集合上给出了基础逻辑代数BL的表示定理.

  10. Histopathological assessment of C57Bl/J mice organs exposed to tannery effluents

    OpenAIRE

    Joyce Moreira de Souza; Abraão Tiago Batista Guimarães; Wellington Alves Mizael da Silva; Bruna de Oliveira Mendes; Dieferson da Costa Estrela; Aline Sueli de Lima Rodrigues; Adriana da Silva Santos; Guilherme Malafaia

    2016-01-01

    The effluent produced in tanneries can cause environmental damage and public health problems when disposed of improperly. However, few toxicological studies have evaluated the effects of the intake of tannery wastewater by mammals. The objective of this study is the histological assessment of organs of C57Bl/J mice exposed to the intake of different concentrations of raw tannery effluents, beginning with the hypothesis that these effluents can cause damage to the histological structure of the...

  11. Effect of High-Fat Diet on Peripheral Neuropathy in C57BL/6 Mice

    OpenAIRE

    Lingling Xu; Dou Tang; Meiping Guan; Cuihua Xie; Yaoming Xue

    2014-01-01

    Objective. Dyslipidemia may contribute to the development of peripheral neuropathy, even in prediabetics; however, few studies have evaluated vascular dysfunction and oxidative stress in patients with peripheral neuropathy. Methods. Using high-fat diet- (HFD-) induced prediabetic C57BL/6 mice, we assessed motor and sensory nerve conduction velocity (NCV) using a BIOPAC System and thermal algesia with a Plantar Test (Hargreaves' method) Analgesia Meter. Intraepidermal nerve fiber density and m...

  12. Object and Objective Lost?

    DEFF Research Database (Denmark)

    Lopdrup-Hjorth, Thomas

    2015-01-01

    This paper explores the erosion and problematization of ‘the organization’ as a demarcated entity. Utilizing Foucault's reflections on ‘state-phobia’ as a source of inspiration, I show how an organization-phobia has gained a hold within Organization Theory (OT). By attending to the history...... of this organization-phobia, the paper argues that OT has become increasingly incapable of speaking about its core object. I show how organizations went from being conceptualized as entities of major importance to becoming theoretically deconstructed and associated with all kinds of ills. Through this history......, organizations as distinct entities have been rendered so problematic that they have gradually come to be removed from the center of OT. The costs of this have been rather significant. Besides undermining the grounds that gave OT intellectual credibility and legitimacy to begin with, the organization-phobia...

  13. Renal dopaminergic defect in C57Bl/6J mice.

    Science.gov (United States)

    Escano, Crisanto S; Armando, Ines; Wang, Xiaoyan; Asico, Laureano D; Pascua, Annabelle; Yang, Yu; Wang, Zheng; Lau, Yuen-Sum; Jose, Pedro A

    2009-12-01

    The C57Bl/6J mouse strain, the genetic background of many transgenic and gene knockout models, is salt sensitive and resistant to renal injury. We tested the hypothesis that renal dopaminergic function is defective in C57Bl/6J mice. On normal NaCl (0.8%, 1 wk) diet, anesthetized and conscious (telemetry) blood pressures were similar in C57Bl/6J and SJL/J mice. High NaCl (6%, 1 wk) increased blood pressure (approximately 30%) in C57Bl/6J but not in SJL/J mice and urinary dopamine to greater extent in SJL/J than in C57Bl/6J mice. Absolute and fractional sodium excretions were lower in SJL/J than in C57Bl/6J mice. The blood pressure-natriuresis plot was shifted to the right in C57Bl/6J mice. Renal expressions of D(1)-like (D(1)R and D(5)R) and angiotensin II AT(1) receptors were similar on normal salt, but high salt increased D(5)R only in C57Bl/6J. GRK4 expression was lower on normal but higher on high salt in C57Bl/6J than in SJL/J mice. Salt increased the excretion of microalbumin and 8-isoprostane (oxidative stress marker) and the degree of renal injury to a greater extent in SJL/J than in C57Bl/6J mice. A D(1)-like receptor agonist increased sodium excretion whereas a D(1)-like receptor antagonist decreased sodium excretion in SJL/J but not in C57Bl/6J mice. In contrast, parathyroid hormone had a similar natriuretic effect in both strains. These results show that defective D(1)-like receptor function is a major cause of salt sensitivity in C57Bl/6J mice, decreased renal dopamine production might also contribute. The relative resistance to renal injury of C57Bl/6J may be a consequence of decreased production of reactive oxygen species.

  14. The REX survey as a tool to test the beaming model for BL Lacs

    CERN Document Server

    Caccianiga, A; MacCacaro, T; Wolter, A; Gioia, I M

    1999-01-01

    In the context of the beaming model (BM) BL Lac and FR I radio galaxies are thought to be the same class of sources seen at different angles. If this picture is correct, we expect to find some transition objects with intermediate properties between the two classes. To date, this intermediate population of objects is missing, probably due to the limiting fluxes of the current X-ray/radio surveys and/or to the criteria used to separate BL Lacs from normal elliptical galaxies. As pointed out by Browne and Marcha (1993), the detection of the transition objects requires particular attention since the "weak" BL Lac nucleus is hidden by the light of the host elliptical galaxy. A useful criterion often used to assess the presence of a non-thermal source, in addition to the stellar emission of the host galaxy, is the Ca contrast at 4000 AA (K/sub 4000/). This quantity, which is defined as the relative depression of the spectrum across 4000 AA, is a typical feature observed in a "normal" elliptical galaxy; the samples ...

  15. VizieR Online Data Catalog: The CLASS BL Lac sample (Marcha+, 2013)

    Science.gov (United States)

    Marcha, M. J. M.; Caccianiga, A.

    2014-04-01

    This paper presents a new sample of BL Lac objects selected from a deep (30mJy) radio survey of flat spectrum radio sources (the CLASS blazar survey). The sample is one of the largest well-defined samples in the low-power regime with a total of 130 sources of which 55 satisfy the 'classical' optical BL Lac selection criteria, and the rest have indistinguishable radio properties. The primary goal of this study is to establish the radio luminosity function (RLF) on firm statistical ground at low radio luminosities where previous samples have not been able to investigate. The gain of taking a peek at lower powers is the possibility to search for the flattening of the luminosity function which is a feature predicted by the beaming model but which has remained elusive to observational confirmation. In this study, we extend for the first time the BL Lac RLF down to very low radio powers ~1022W/Hz, i.e. two orders of magnitude below the RLF currently available in the literature. In the process, we confirm the importance of adopting a broader, and more physically meaningful set of classification criteria to avoid the systematic missing of low-luminosity BL Lacs. Thanks to the good statistics we confirm the existence of weak but significant positive cosmological evolution for the BL Lac population, and we detect, for the first time the flattening of the RLF at L~1025W/Hz in agreement with the predictions of the beaming model. (1 data file).

  16. Behavioral profiles of three C57BL/6 substrains

    Directory of Open Access Journals (Sweden)

    Naoki Matsuo

    2010-06-01

    Full Text Available C57BL/6 inbred strains of mice are widely used in knockout and transgenic research. To evaluate the loss-of-function and gain-of-function effects of the gene of interest, animal behaviors are often examined. However, an issue of C57BL/6 substrains that is not always appreciated is that behaviors are known to be strongly influenced by genetic background. To investigate the behavioral characteristics of C57BL/6 substrains, we subjected C57BL/6J, C57BL/6N, and C57BL/6C mice to a behavior test battery. We performed both a regular-scale analysis, in which experimental conditions were tightly-controlled, and meta-analysis from large number of behavioral data that we have collected so far through the comprehensive behavioral test battery applied to 700-2,200 mice in total. Significant differences among the substrains were found in the results of various behavioral tests, including the open field, rotarod, elevated plus maze, prepulse inhibition, Porsolt forced swim, and spatial working memory version of the 8-arm radial maze. Our results show a divergence of behavioral performance in C57BL/6 substrains, which suggest that small genetic differences may have a great influence on behavioral phenotypes. Thus, the genetic background of different substrains should be carefully chosen, equated, and considered in the interpretation of mutant behavioral phenotypes.

  17. Dicty_cDB: FC-BL11 [Dicty_cDB

    Lifescience Database Archive (English)

    Full Text Available FC (Link to library) FC-BL11 (Link to dictyBase) - - - Contig-U15198-1 FC-BL11Z (Li...nk to Original site) - - FC-BL11Z 671 - - - - Show FC-BL11 Library FC (Link to library) Clone ID FC-BL11 (Li.../dictycdb.biol.tsukuba.ac.jp/CSM/FC/FC-BL/FC-BL11Q.Seq.d/ Representative seq. ID FC-BL1...1Z (Link to Original site) Representative DNA sequence >FC-BL11 (FC-BL11Q) /CSM/FC/FC-BL/FC-BL11Q.Seq....ALDNSCSLVDGTEDVYQQIFYSPSFQ*in*ifeitikkkkk Homology vs CSM-cDNA Score E Sequences producing significant align

  18. B-L assisted anomaly mediation and the radiative B-L symmetry breaking

    Energy Technology Data Exchange (ETDEWEB)

    Kikuchi, Tatsuru [Theory Division, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)], E-mail: tatsuru@post.kek.jp; Kubo, Takayuki [Theory Division, KEK, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan); Graduate University for Advanced Studies, Oho 1-1, Tsukuba, Ibaraki 305-0801 (Japan)], E-mail: kubotaka@post.kek.jp

    2008-10-30

    Anomaly mediated supersymmetry breaking implemented in the minimal supersymmetric standard model (MSSM) is known to suffer from the tachyonic slepton problem leading to breakdown of electric charge conservation. We show however that when MSSM is extended to explain small neutrino masses by gauging the B-L symmetry, the slepton masses can be positive due to the Z{sup '} mediation contributions. We obtain various soft supersymmetry breaking mass spectra, which are different from those obtained in the conventional anomaly mediation scenario. Then there would be a distinct signature of this scenario at the LHC.

  19. Construction of a recombinant plasmid pGEX-Sj26GST of Schistosoma japonicum and expression in Escherichia coli BL21( DE3)

    Institute of Scientific and Technical Information of China (English)

    张丽

    2014-01-01

    Objective To construct and express a recombinant plasmid pGEX-Sj26GST of Schistosoma japonicum(Sj)in Escherichia coli(E.coli)BL21(DE3).Methods Total RNA was extracted from Sj adult worms by RNeasy Mini kit,26 kilodalton glutathione-S-transferases of Schistosoma japonicum(Sj26GST)antigen gene was amplified by real-time PCR(RT-PCR)from the total RNA,then cloned into a prokaryotic expression plasmid pGEX-1λT and transformed into E.coli BL21(DE3)to construct pGEX-Sj26GST;BL21(pGEX-

  20. Multiwavelength study of quiescent states of MRK 421 with unprecedented hard x-ray coverage provided by NuSTAR in 2013

    DEFF Research Database (Denmark)

    Baloković, M.; Paneque, D.; Madejski, G.;

    2016-01-01

    We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy (VHE) γ-ray band...

  1. On the Superluminal Motion of Radio-Loud AGNs

    Indian Academy of Sciences (India)

    Zhi-Bin Zhang; Yi-Zhen Zhang

    2011-03-01

    Apparent superluminal motion of different radio-loud AGNs are similarly related with beaming effect. The cosmological expanding effect would play no part in the superluminal motion of radio galaxies, BL Lacertae objects as well as quasars.Meanwhile, we confirm that estimates for apparent velocity app and Doppler boosting factor based on multi-wavelength combination and variability are comparable.

  2. The Sedentary Multi-Frequency Survey; 1, Statistical Identification and Cosmological Properties of HBL BL Lacs

    CERN Document Server

    Giommi, P; Padovani, P

    1999-01-01

    We have assembled a multi-frequency database by cross-correlating the NVSS catalog of radio sources with the RASSBSC list of soft X-ray sources, obtaining optical magnitude estimates from the Palomar and UK Schmidt surveys as provided by the APM and COSMOS on-line services. By exploiting the nearly unique broad-band properties of High-Energy Peaked (HBL) BL Lacs we have statistically identified a sample of 218 objects that is expected to include about 85% of BL Lacs and that is therefore several times larger than all other published samples of HBLs. Using a subset (155 objects) that is radio flux limited and statistically well-defined we have derived the \\vovm distribution and the LogN-LogS of extreme HBLs (fx/fr >= 3E-10 erg/cm2/s/Jansky) down to 3.5 mJy. We find that the LogN-LogS flattens around 20 mJy and that = 0.42 +/- 0.02. This extends to the radio band earlier results, based on much smaller X-ray selected samples, about the anomalous cosmological observational properties of HBL BL Lacs. A comparison...

  3. Intuitionistic fuzzy filters of BL-algebras%BL-代数的直觉模糊滤子

    Institute of Scientific and Technical Information of China (English)

    房卫平

    2013-01-01

    Based on the theory of BL-algebras and intuitionistic fuzzy sets ,intuitionistic fuzzy filters and intuitionistic fuzzy prime filters are defined through the method of intuitionistic sets .Moreover ,some properties of intuitionistic fuzzy filters and intuitionistic fuzzy prime filters of BL-algebras are discussed and the relations between them are studied .Then ,the intuitionistic fuzzy filters generated by intuition-istic fuzzy set in BL-algebras is studied .Finally ,the algebraic structure of all intuitionistic fuzzy filters is discussed .%在 BL-代数和直觉模糊集理论的基础上,应用直觉模糊集的方法,定义了 BL-代数上直觉模糊滤子和直觉模糊素滤子。然后,讨论了直觉模糊滤子和直觉模糊素滤子的相关性质以及如何由直觉模糊集生成直觉模糊滤子的方法;最后,研究了 BL-代数上的直觉模糊滤子的全体的代数结构。

  4. C57BL/6J小鼠听力损失与认知功能下降的相关性%Correlation between age-related hearing loss and impairment of cognition in C57BL/6J mice

    Institute of Scientific and Technical Information of China (English)

    于亚峰; 翟丰; 戴春富; 胡金家

    2011-01-01

    Objective To explore the correlation of age-related hearing loss and cognition impairment in C57BL/6J mice by observing hearing, cognitive function and synapses. Methods C57BL/6J and CBA/CaJ mice were divided into 3 groups. The hearing and cognitive functions of each animal was tested. And the ultrastructure of synapses was simultaneously observed for C57BL/6J mice. Results The 24-26-week-old C57BL/6J mice developed moderate hearing loss while the 42- 44-week-old C57BL/6J counterparts suffered profound hearing loss. Whereas excellent hearing was maintained in 3 groups of CBA/CaJ mice within 44 weeks. During cognitive test, the performance of 42 -44-week-old C57BL/6J mice was significantly worse than CBA/CaJ mice. During probe test, the number of platform crossing of 42 - 44-week-old C57BL/6J mice was smaller than that of CBA/CaJ mice(0.5 ± 0.6 vs 1.9 ± 1.6; P < 0.05 ). The 42 -44-week-old C57BL/6J mice had a wider synaptic cleft and a thinner postsynaptic density than the 24 -26-week-old C57 BL/6J counterparts [synaptic cleft: ( 19.4 ± 0.5 ) nm vs ( 1 1. 9 ± 0.7 ) nm; postsynaptic density:(15.2 ±0. 5) nm vs (27.8 ±2.0) nm; both P <0.05]. Furthermore, the degeneration of synapses in hippocampus CA3 area of C57BL/6J mice were clearly observed at 42 -44 weeks of age, but not seen in CBA/CaJ mice. Conclusion Age-related hearing loss might impact on the cognition impairment in C57 BL/6J mice.%目的 通过对老年性聋模型鼠C57BL/6J和对照组CBA/CaJ小鼠听力检测,认知行为检测以及海马CA3区突触超微结构的观察,探讨C57BL/6J小鼠年龄相关性听力损失与认知功能下降的关系。方法 将C57BL/6J小鼠根据听力随年龄的变化,按年龄分为3组:6~8周、24~26周、42~44周,每组10只。CBA/CaJ小鼠按同样的年龄也分为3组,每组9只。以TDT-Ⅲ型ABR测试仪检测听力,Morris水迷宫实验检测认知行为,透射电镜观察海马突触超微结构。结果 C57 BL/6J小鼠24~ 26

  5. A study to investigate needle insertion atShenshu (BL23) to puncture psoas major muscle

    Institute of Scientific and Technical Information of China (English)

    Kwan Leung Chia; Rainer Viktor Haberberger

    2016-01-01

    OBJECTIVE: It is unknown whether the psoas major muscle, thought to be a key muscle for treatment of lower back pain, can be punctured at Shenshu (BL23). METHODS: Twelve dissected specimens were used for studying the needling pathway of BL23 by perpendicularly inserting the depth-measuring blade of a vernier caliper at BL23. Dimensions of psoas muscle were measured. Correlation studies were conducted. In addition, our samples were grouped by gender and underlying medical conditions for analysis. RESULTS:Half (50%) of the needle insertions successfully punctured psoas muscle. The mean depth of needle insertion to puncture psoas muscle (Dmin) in the group with short-term underlying medical conditions was 38.0 mm (interquartile range 29.0–51.8 mm), approximately 6 mm deeper than 32.0 (29.3–42.5) mm in the group with long-term health problems (P = 0.041). The cross-sectional area (CSA) of psoas muscle in the former group was on average approximately 1.5 times that of the latter group (P = 0.04). When the data were analysed by gender, the thickness of psoas muscle in the male group was 19.0 (6.5–24.0) mm compared to 19.5 (5.8–34.8) mm in the female group (P = 0.02). The age in the female group (P = 0.04) and the body length of the total group (P = 0.04) negatively correlated to Dmin. CONCLUSION: Needle insertion at BL23 might be able to puncture psoas muscle. Differences in the CSA of psoas muscle and Dmin were observed in groups with short-term and long-term underlying medical conditions.

  6. Estimation of the extragalactic background light using TeV observations of BL Lac objects

    Energy Technology Data Exchange (ETDEWEB)

    Sinha, Atreyee; Acharya, B. S. [Department of High Energy Physics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400005 (India); Sahayanathan, S.; Godambe, S. [Astrophysical Sciences Division, Bhabha Atomic Research Center, Mumbai (India); Misra, R., E-mail: atreyee@tifr.res.in, E-mail: acharya@tifr.res.in, E-mail: sunder@barc.ernet.in, E-mail: gsagar@barc.ernet.in, E-mail: rmisra@iucaa.ernet.in [Inter-University Center for Astronomy and Astrophysics, Post Bag 4, Ganeshkhind, Pune 411007 (India)

    2014-11-01

    The very high-energy (VHE) gamma-ray spectral index of high-energy peaked blazars correlates strongly with its corresponding redshift, whereas no such correlation is observed in the X-ray or GeV bands. We attribute this correlation to photon-photon absorption of TeV photons with the extragalactic background light (EBL), and utilizing this we compute the allowed flux range for the EBL, which is independent of previous estimates. The observed VHE spectrum of the sources in our sample can be well approximated by a power law, and if the de-absorbed spectrum is also assumed to be a power law, then we show that the spectral shape of EBL will be εn(ε) ∼ klog (ε/ε {sub p}). We estimate the range of values for the parameters defining the EBL spectrum, k and ε {sub p}, such that the correlation of the intrinsic VHE spectrum with redshift is nullified. The estimated EBL depends only on the observed correlation and the assumption of a power-law source spectrum. Specifically, it does not depend on the spectral modeling or radiative mechanism of the sources or on any theoretical shape of the EBL spectrum obtained through cosmological calculations. The estimated EBL spectrum is consistent with the upper and lower limits imposed by different observations. Moreover, it also agrees closely with the theoretical estimates obtained through cosmological evolution models.

  7. Fractal Property in the Light Curve of BL Lac Object S5 0716+714

    Indian Academy of Sciences (India)

    J. W. Ou; Y. G. Zheng

    2014-09-01

    In this paper, we compile the historical R-band data of S5 0716+714 from literature and obtain its fractal dimension by using a fractal method and then simulate the data with the Weierstrass–Mandelbrot (W–M) function. It is considered that the light curve has a fractal property.

  8. An active state of the BL Lac Object Markarian 421 detected by INTEGRAL in April 2013

    CERN Document Server

    Pian, E; Fiocchi, M; Bazzano, A; Foschini, L; Tavecchio, F; Bianchin, V; Boissay, R; Castignani, G; Ferrigno, C; Raiteri, C M; Villata, M; Beckmann, V; D'Ammando, F; Hudec, R; Malaguti, G; Maraschi, L; Pursimo, T; Romano, P; Soldi, S; Stamerra, A; Treves, A; Ubertini, P; Vercellone, S; Walter, R

    2013-01-01

    (abridged) Multi-wavelength variability of blazars offers effective insight into the mechanisms through which energy is propagated from the center down the jet. In this context, we activated INTEGRAL observations of the blazar Markarian 421 in an active state on 16-21 April 2013, and complemented them with Fermi-LAT data. We obtained well sampled optical, soft and hard X-ray light curves that show the presence of two flares, the first one reaching a brighter maximum than the second one at X-rays. The average flux in the 20-100 keV range is 9.1e-11 cgs and the nuclear average apparent magnitude, corrected for Galactic extinction, is V ~ 12.2. In the time-resolved JEMX+IBIS spectra we see a change of spectral slope at an energy that correlates with flux, as expected in refreshed energy injections in a population of electrons that cool thereafter via synchrotron radiation. During the observation, the variability level increases monotonically from the optical to the hard X-rays, and the cross-correlation analysis...

  9. Transcriptional analysis of oligosaccharide utilization by Bifidobacterium lactis Bl-04

    DEFF Research Database (Denmark)

    Andersen, Joakim Mark; Barrangou, Rodolphe; Abou Hachem, Maher

    2013-01-01

    transcriptomes of Bifidobacterium animalis subsp. lactis Bl-04, induced by 11 potential prebiotic oligosaccharides were analyzed to identify the genetic loci involved in the uptake and catabolism of α- and β-linked hexoses, and β-xylosides. RESULTS: The overall transcriptome was modulated dependent on the type...... in the breadth and selectivity of prebiotic utilization by bifidobacteria. CONCLUSION: This study identified the differential gene expression for utilization of potential prebiotics highlighting the extensive capabilities of Bifidobacterium lactis Bl-04 to utilize oligosaccharides. Results provide insights...

  10. New statistical results on the optical IDV data of BL Lac S5 0716+714

    CERN Document Server

    Danila, B; Mocanu, G

    2014-01-01

    This paper reports on the statistical behaviour of the optical IntraDay Variability of BL Lac S5 0716+714. Available IntraDay Variability data in the optical is tested to see whether or not the magnitude is log-normally distributed. It was consistently found that this is not the case. This is in agreement with a previous discussion for data for the same object but in a different observational period. Simultaneously, the spectral slope of the light curves is calculated. The implications of these findings for models which discuss both the location and the source of IntraDay Variability are presented.

  11. BL Lac A New Ultrahigh-Energy Gamma-Ray Source

    CERN Document Server

    Neshpor, Y I; Stepanian, A A; Kalekin, O R; Jogolev, N A; Fomin, V P; Shitov, V G; Neshpor, Yu. I.

    2001-01-01

    The active galactic nucleus BL Lac was observed with the Gt-48 atmospheric Cherenkov detector of the Crimean Astrophysical Observatory from July 23-September 1, 1998, in order to search for ultrahigh-energy gamma-ray (>1 TeV) emission. The object was in the field of view of the detector for more than 24 hours. The source was detected with a high level of confidence (7.2 sigma), with a flux equal to (2.1+/-0.4)x10^{-11} photons cm^{-2}s^{-1}.

  12. Object crowding.

    Science.gov (United States)

    Wallace, Julian M; Tjan, Bosco S

    2011-05-25

    Crowding occurs when stimuli in the peripheral fields become harder to identify when flanked by other items. This phenomenon has been demonstrated extensively with simple patterns (e.g., Gabors and letters). Here, we characterize crowding for everyday objects. We presented three-item arrays of objects and letters, arranged radially and tangentially in the lower visual field. Observers identified the central target, and we measured contrast energy thresholds as a function of target-to-flanker spacing. Object crowding was similar to letter crowding in spatial extent but was much weaker. The average elevation in threshold contrast energy was in the order of 1 log unit for objects as compared to 2 log units for letters and silhouette objects. Furthermore, we examined whether the exterior and interior features of an object are differentially affected by crowding. We used a circular aperture to present or exclude the object interior. Critical spacings for these aperture and "donut" objects were similar to those of intact objects. Taken together, these findings suggest that crowding between letters and objects are essentially due to the same mechanism, which affects equally the interior and exterior features of an object. However, for objects defined with varying shades of gray, it is much easier to overcome crowding by increasing contrast.

  13. Performance Objectives

    Science.gov (United States)

    1978-12-01

    objectives may direct students’ learning (Duchastel and Merrill, 1973; Kapfer , 1970; Kibler et al., 1974), since such objectives may provide...matter learning. Journal of Educational Psychology, 62(1): 67-70 (1971). Kapfer , P. G. Behavioral objectives and the curriculum processor. Educational

  14. The cloned 1-aminocyclopropane-1-carboxylate (ACC) deaminase gene from Sinorhizobium sp. strain BL3 in Rhizobium sp. strain TAL1145 promotes nodulation and growth of Leucaena leucocephala.

    Science.gov (United States)

    Tittabutr, Panlada; Awaya, Jonathan D; Li, Qing X; Borthakur, Dulal

    2008-06-01

    The objective of this study was to determine the role of 1-aminocyclopropane-1-carboxylate (ACC) deaminase of symbionts in nodulation and growth of Leucaena leucocephala. The acdS genes encoding ACC deaminase were cloned from Rhizobium sp. strain TAL1145 and Sinorhizobium sp. BL3 in multicopy plasmids, and transferred to TAL1145. The BL3-acdS gene greatly enhanced ACC deaminase activity in TAL1145 compared to the native acdS gene. The transconjugants of TAL1145 containing the native or BL3 acdS gene could grow in minimal media containing 1.5mM ACC, whereas BL3 could tolerate up to 3mM ACC. The TAL1145 acdS gene was inducible by mimosine and not by ACC, while the BL3 acdS gene was highly inducible by ACC and not by mimosine. The transconjugants of TAL1145 containing the native- and BL3-acdS genes formed nodules with greater number and sizes, and produced higher root mass on L. leucocephala than by TAL1145. This study shows that the introduction of multiple copies of the acdS gene increased ACC deaminase activities of TAL1145 and enhanced its symbiotic efficiency on L. leucocephala.

  15. The gravitational wave spectrum from cosmological B-L breaking

    Energy Technology Data Exchange (ETDEWEB)

    Buchmüller, W.; Domcke, V.; Kamada, K. [Deutsches Elektronen-Synchrotron DESY, 22607 Hamburg (Germany); Schmitz, K., E-mail: buchmuwi@mail.desy.de, E-mail: valerie.domcke@desy.de, E-mail: kohei.kamada@desy.de, E-mail: kai.schmitz@ipmu.jp [Kavli IPMU (WPI), University of Tokyo, Kashiwa 277-8583 (Japan)

    2013-10-01

    Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying Ω{sub GW}h{sup 2} ∼ 10{sup −13}–10{sup −8}, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO, ET, BBO and DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.

  16. The gravitational wave spectrum from cosmological B-L breaking

    Energy Technology Data Exchange (ETDEWEB)

    Buchmueller, W.; Domcke, V.; Kamada, K. [Deutsches Elektronen-Synchrotron (DESY), Hamburg (Germany); Schmitz, K. [Tokyo Univ., Kashiwa (Japan). Kavli IPMU (WPI)

    2013-05-15

    Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying {Omega}{sub GW}h{sup 2}{proportional_to}10{sup -13}-10{sup -8}, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eLISA, advanced LIGO and BBO/DECIGO will reach the sensitivity needed to test the predictions from cosmological B-L breaking.

  17. Probing classically conformal $B-L$ model with gravitational waves

    CERN Document Server

    Jinno, Ryusuke

    2016-01-01

    We study the cosmological history of the classical conformal $B-L$ gauge extension of the standard model, in which the physical scales are generated via the Coleman-Weinberg-type symmetry breaking. Especially, we consider the thermal phase transition of the U$(1)_{B-L}$ symmetry in the early universe and resulting gravitational-wave production. Due to the classical conformal invariance, the phase transition tends to be a first-order one with ultra-supercooling, which enhances the strength of the produced gravitational waves. We show that, requiring (1) U$(1)_{B-L}$ is broken after the reheating, (2) the $B-L$ gauge coupling does not blow up below the Planck scale, (3) the thermal phase transition completes in almost all the patches in the universe, the gravitational wave spectrum can be as large as $\\Omega_{\\rm GW} \\sim 10^{-8}$ at the frequency $f \\sim 0.01$-$1$Hz for some model parameters, and a vast parameter region can be tested by future interferometer experiments such as eLISA, LISA, BBO and DECIGO.

  18. Centronotus fasciatus Bl. & Schn. aan de Nederlandsche kust

    NARCIS (Netherlands)

    Popta, C.M.L.

    1916-01-01

    In de collectie van het Leidsche Museum bevindt zich een Centronotus fasciatus Bl. & Sch., volgens de opgave op het etiket afkomstig van de Hollandsche kust. De kenmerken van dit individu, dat 230 mm. lang is, zijn: De hoogte van het langwerpige lichaam gaat 9 7/12 en de lengte van den, evenals het

  19. On the redshifts of the BL Lac 3FGL J0909.0+2310 and its close companion

    Science.gov (United States)

    Rosa-González, D.; Coutiño de León, S.; Mayya, Y. D.; Carramiñana, A.; Aretxaga, I.; Becerra González, J.; Furniss, A.; Terlevich, E.; Vega, O.; Méndez-Abreu, J.; León Tavares, J.; Longinotti, A. L.; Terlevich, R.

    2017-04-01

    We report on the redshift of the BL Lac object 3FGL J0909.0+2310 based on observations obtained with the OSIRIS Multi-Object Spectrograph (MOS) mounted on the 10.4-m Gran Telescopio Canarias. A redshift of 0.432 ± 0.002 was obtained by the identification of three absorption features (Ca II K&H and the G band) detected in the spectrum of the BL Lac host galaxy. The closest object to the BL Lac at an angular separation of 3.8 arcsec (∼21 kpc at this distance) has a similar redshift of 0.431 ± 0.002. This companion galaxy could be the most likely cause of the nuclear activity as postulated by studies based on more extended data sets and cosmological models. MOS allows us to study the object's neighbourhood within a field of view of approximately 7 × 2 arcmin2 and we find two small groups of galaxies at redshifts 0.28 and 0.39 which are probably not related to the activity of 3FGL J0909.0+2310.

  20. On the Redshifts of the BL Lac 3FGL J0909.0+2310 and its Close Companion

    CERN Document Server

    Rosa-Gonzalez, D; Mayya, Y D; Carramiñana, A; Aretxaga, I; Gonzalez, J Becerra; Furniss, A; Terlevich, E; Vega, O; Mendez-Abreu, J; Tavares, J Leon; Longinotti, A L; Terlevich, R

    2016-01-01

    We report on the redshift of the BL Lac object 3FGL J0909.0+2310 based on observations obtained with the OSIRIS Multi Object Spectrograph (MOS) mounted on the 10.4-m Gran Telescopio Canarias. A redshift of 0.432+/-0.002 was obtained by the identification of three absorption features (CaII K&H and G-band) detected in the spectrum of the BL Lac host galaxy. The closest object to the BL Lac at an angular separation of 3.8" (~21 kpc at this distance) has a similar redshift of 0.431+/-0.002. This companion galaxy could be the most likely cause of the nuclear activity as postulated by studies based on more extended data sets and cosmological models. MOS allows us to study the object's neighbourhood within a field of view of approximately 7'x2' and we find two small groups of galaxies at redshifts 0.28 and 0.39 which are probably not related to the activity of 3FGL~J0909.0+2310.

  1. Temporal distributions, habitat associations and behaviour of the green lizard (Lacerta bilineata and wall lizard (Podarcis muralis on roads in a fragmented landscape in Western France

    Directory of Open Access Journals (Sweden)

    Roger Meek

    2014-12-01

    Full Text Available Observations of the green lizard (Lacerta bilineata and wall lizard (Podarcis muralis on roads in Western France indicated that basking close to the road edge was the predominant activity in L. bilineata but P. muralis mostly foraged. Spatial locations of road mortalities in both species reflected this with the median distances from the road edge greater in P. muralis. Temporal differences in road presence, based on mortality counts and those of live lizards, indicated significantly more lizards were present on roads during late summer and autumn, especially in P. muralis. A significant correlation was found between the monthly presence of live lizards and monthly road mortalities in P. muralis (r = 0.73 but not in L. bilineata (r = 0.64.  Numbers of L. bilineata found on roads bisecting low-density urban areas and roads bordered by hedgerows were higher than expected in relation to the occurrence of these habitats at roadsides. In P. muralis higher than expected numbers were found alongside low-density urban areas and roads bisecting woodland. Generally both species were less commonly seen on roads alongside agricultural areas with no hedgerow border.

  2. No Interstitial Telomeres on Autosomes but Remarkable Amplification of Telomeric Repeats on the W Sex Chromosome in the Sand Lizard (Lacerta agilis).

    Science.gov (United States)

    Matsubara, Kazumi; Uno, Yoshinobu; Srikulnath, Kornsorn; Matsuda, Yoichi; Miller, Emily; Olsson, Mats

    2015-01-01

    Telomeres are repeat (TTAGGG) n sequences that form terminal ends of chromosomes and have several functions, such as protecting the coding DNA from erosion at mitosis. Due to chromosomal rearrangements through evolutionary history (e.g., inversions and fusions), telomeric sequences are also found between the centromere and the terminal ends (i.e., at interstitial telomeric sites, ITSs). ITS telomere sequences have been implicated in heritable disease caused by genomic instability of ITS polymorphic variants, both with respect to copy number and sequence. In the sand lizard (Lacerta agilis), we have shown that telomere length is predictive of lifetime fitness in females but not males. To assess whether this sex specific fitness effect could be traced to ITSs differences, we mapped (TTAGGG) n sequences using fluorescence in situ hybridization in fibroblast cells cultured from 4 specimens of known sex. No ITSs could be found on autosomes in either sex. However, females have heterogametic sex chromosomes in sand lizards (ZW, 2n = 38) and the female W chromosome showed degeneration and remarkable (TTAGGG) n amplification, which was absent in the Z chromosomes. This work warrants further research on sex chromosome content, in particular of the degenerate W chromosome, and links to female fitness in sand lizards.

  3. Ultrastructural features of the differentiating thyroid primordium in the sand lizard (Lacerta agilis L.) from the differentiation of the cellular cords to the formation of the follicular lumen.

    Science.gov (United States)

    Rupik, Weronika; Kowalska, Magdalena; Swadźba, Elwira; Maślak, Robert

    2016-04-01

    The differentiation of the thyroid primordium of lacertilian species is poorly understood. The present study reports on the ultrastructural analysis of the developing thyroid primordium in the sand lizard (Lacerta agilis) during the early stages of differentiation. The early thyroid primordium of sand lizard embryos was composed of cellular cords that contained single cells with a giant lipid droplet, which were eliminated by specific autophagy (lipophagy). The follicular lumens at the periphery of the primordium differentiated even before the division of the cellular cords. When the single cells within the cords started to die through paraptosis, the adjacent cells started to polarise and junctional complexes began to form around them. After polarisation and clearing up after the formation of the lumens, the cellular cords divided into definitive follicles. The cellular cords in the central part of the primordium started to differentiate later than those at the periphery. The cellular cords divided into presumptive follicles first and only later differentiated into definitive follicles. During this process, a population of centrally located cells was removed through apoptosis to form the lumen. Although the follicular lumen in sand lizard embryos is differentiated by cavitation similar to that in the grass snake, there were very important differences during the early stages of the differentiation of the cellular cords and the formation of the thyroid follicles.

  4. Identification of the linkage group of the Z sex chromosomes of the sand lizard (Lacerta agilis, Lacertidae) and elucidation of karyotype evolution in lacertid lizards.

    Science.gov (United States)

    Srikulnath, Kornsorn; Matsubara, Kazumi; Uno, Yoshinobu; Nishida, Chizuko; Olsson, Mats; Matsuda, Yoichi

    2014-12-01

    The sand lizard (Lacerta agilis, Lacertidae) has a chromosome number of 2n = 38, with 17 pairs of acrocentric chromosomes, one pair of microchromosomes, a large acrocentric Z chromosome, and a micro-W chromosome. To investigate the process of karyotype evolution in L. agilis, we performed chromosome banding and fluorescent in situ hybridization for gene mapping and constructed a cytogenetic map with 86 functional genes. Chromosome banding revealed that the Z chromosome is the fifth largest chromosome. The cytogenetic map revealed homology of the L. agilis Z chromosome with chicken chromosomes 6 and 9. Comparison of the L. agilis cytogenetic map with those of four Toxicofera species with many microchromosomes (Elaphe quadrivirgata, Varanus salvator macromaculatus, Leiolepis reevesii rubritaeniata, and Anolis carolinensis) showed highly conserved linkage homology of L. agilis chromosomes (LAG) 1, 2, 3, 4, 5(Z), 7, 8, 9, and 10 with macrochromosomes and/or macrochromosome segments of the four Toxicofera species. Most of the genes located on the microchromosomes of Toxicofera were localized to LAG6, small acrocentric chromosomes (LAG11-18), and a microchromosome (LAG19) in L. agilis. These results suggest that the L. agilis karyotype resulted from frequent fusions of microchromosomes, which occurred in the ancestral karyotype of Toxicofera and led to the disappearance of microchromosomes and the appearance of many small macrochromosomes.

  5. The 2003-4 multisite photometric campaign for the Beta Cephei and eclipsing star 16 (EN) Lacertae with an Appendix on 2 Andromedae, the variable comparison star

    CERN Document Server

    Jerzykiewicz, M; Daszynska-Daszkiewicz, J; Pigulski, A; Poretti, E; Rodriguez, E; Amado, P J; Kolaczkowski, Z; Uytterhoeven, K; Dorokhova, T N; Dorokhov, N I; Lorenz, D; Zsuffa, D; Kim, S -L; Bourge, P -O; Acke, B; De Ridder, J; Verhoelst, T; Drummond, R; Movchan, A I; Lee, J -A; Steslicki, M; Molenda-Zakowicz, J; Garrido, R; Kim, S -H; Michalska, G; Paparo, M; Antoci, V; Aerts, C

    2015-01-01

    A multisite photometric campaign for the Beta Cephei and eclipsing variable 16 Lacertae is reported. 749 h of high-quality differential photoelectric Stromgren, Johnson and Geneva time-series photometry were obtained with ten telescopes during 185 nights. After removing the pulsation contribution, an attempt was made to solve the resulting eclipse light curve by means of the computer program EBOP. Although a unique solution was not obtained, the range of solutions could be constrained by comparing computed positions of the secondary component in the Hertzsprung-Russell diagram with evolutionary tracks. For three high-amplitude pulsation modes, the uvy and the Geneva UBG amplitude ratios are derived and compared with the theoretical ones for spherical-harmonic degrees l <= 4. The highest degree, l = 4, is shown to be incompatible with the observations. One mode is found to be radial, one is l = 1, while in the remaining case l = 2 or 3. The present multisite observations are combined with the archival photo...

  6. Anaplasmataceae and Borrelia burgdorferi sensu lato in the sand lizard Lacerta agilis and co-infection of these bacteria in hosted Ixodes ricinus ticks

    Directory of Open Access Journals (Sweden)

    Ekner Anna

    2011-09-01

    Full Text Available Abstract Background Anaplasmataceae and Borrelia burgdorferi s.l. are important tick-borne bacteria maintained in nature by transmission between ticks and vertebrate hosts. However, the potential role of lizards as hosts has not been sufficiently studied. Results The current study showed that 23 of 171 examined sand lizards Lacerta agilis were PCR positive for Anaplasmataceae. The nucleotide sequences of the several selected PCR products showed 100% homology with Anaplasma spp. found in Ixodes ricinus collected in Tunisia and Morocco (AY672415 - AY672420. 1.2% of lizard collar scale samples were PCR positive for B. lusitaniae. In addition, 12 of 290 examined I. ricinus were PCR positive for B. burgdorferi s.l. and 82 were PCR positive for Anaplasmatacea. The number of ticks per lizard and the number of ticks PCR positive for both microorganisms per lizard were strongly correlated. Moreover, we found a significant correlation between numbers of ticks infected with Anaplasmataceae and with B. burgdorferi s.l. living on the same lizard. However, there was no significant correlation between detection of both bacteria in the same tick. Conclusions To the best of our knowledge, this is the first report of Anaplasmataceae DNA and additionally the second report of B. burgdorferi s.l DNA detection in the sand lizard.

  7. Differential Behavioral Characterization Induced in SAMR1 and C57BL/6 Mice%SAMR1和C57BL/6品系阿尔茨海默病模型小鼠行为学比较

    Institute of Scientific and Technical Information of China (English)

    狄波; 李澎涛; 常诚; 都文渊; 贾静

    2012-01-01

    目的:比较SAMR1和C57BL/6两种品系小鼠,双侧海马注射β淀粉样肽段(beta-amyloid,Aβ)建立阿尔茨海默病动物模型后行为学差异,为建立中药复方药效评价体系提供证据.方法:选用SAMR1和C57BL/6小鼠,双侧海马注射Aβ1-40(每只400 pmol),通过Morris水迷宫、跳台实验检测小鼠行为学变化.结果:行为学显示,两种品系小鼠均出现不同程度学习记忆能力下降.两种品系比较,C57BL/6小鼠空间记忆能力优于SAMR1小鼠,但对电刺激的敏感性不如SAMR1小鼠.结论:SAMR1和C57BL/6小鼠神经行为学表现有差异,可根据不同品系小鼠特点选用相应功效中药复方进行深入研究.%Objective:To compare the effect of hippocampus injection of aggregated B-amyloid peptide-( 1-40) ( AB1-40) (400pmol/ mouse) on behavioral test and morphology in 8 months old male SAMR1 and C57BL/6 mice. Methods:Using Morris water maze test, passive avoidance test (step-down test). Results:SAMR1 and C57B1/6 mice presented spatial learning and memory impairments,de-cline of neuronal cells and accumulation of AB were observed in the hippocampus of both SAMR1 and C57BL/6 mice treated with AB1-40. C57BL/6 mice presented lower sensitivity in the passive avoidance test, whereas they perform better than SAMR1 mice in water maze teat. Conclusion:Differential strains may have diverse responses following A|J1-4O administration. In addition,these models could be useful to develop new drugs for AD.

  8. Radar imaging of binary near-Earth asteroid (357439) 2004 BL86

    Science.gov (United States)

    Benner, Lance A. M.; Brozovic, Marina; Giorgini, Jon D.; Taylor, Patrick A.; Howell, Ellen S.; Busch, Michael W.; Nolan, Michael C.; Jao, Joseph S.; Lee, Clement G.; Ford, H. Alyson; Ghigo, Frank D.

    2015-11-01

    We report radar imaging of near-Earth asteroid 2004 BL86 obtained at Goldstone, Arecibo, Green Bank, and elements of the Very Long Baseline Array between 2015 January 26-31. 2004 BL86 approached within 0.0080 au on January 26, the closest known approach by any object with an absolute magnitude brighter than ~19 until 2027. Prior to the encounter, virtually nothing was known about its physical properties other than its absolute magnitude of 19, which suggested a diameter within a factor of two of 500 m. 2004 BL86 was a very strong radar target that provided an outstanding opportunity for radar imaging and physical characterization. Delay-Doppler images with range resolutions as fine as 3.75 m placed thousands of pixels on the object and confirmed photometric results reported by Pravec et al. (2015, CBET 4063) that 2004 BL86 is a binary system. During the observations, the asteroid moved more than 90 deg and provided a range of viewing geometries. The bandwidth was relatively narrow on Jan. 26, reached a maximum on Jan. 27, and then narrowed on Jan. 28, a progression indicating that the subradar latitude moved across the equator during those days. The images reveal a rounded primary with an equatorial diameter of ~350 m, evidence for ridges, possible boulders, and a pronounced angular feature ~100 m in diameter near one of the poles. Images from Jan. 26 show arcs of radar-bright pixels on the approaching and receding limbs that extend well behind the trailing edge in the middle of the echo. This is the delay-Doppler signature of an oblate shape seen at least a few tens of degrees off the equator. A rough estimate for the diameter of the secondary is ~70 m and its narrow bandwidth is consistent with the 14-h orbital period reported by Pravec et al. (2015). The images are suitable for 3D shape, pole, orbit, and mass estimation. The observations utilized new data taking equipment at Green Bank to receive X-band (8560 MHz, 3.5 cm) transmissions from the 70 m DSS-14

  9. Object theatre

    DEFF Research Database (Denmark)

    Ryöppy, Merja; Heiberg, Andreas

    2015-01-01

    possibilities to emerge. We present a study in which the Object Theatre approach is applied to redesign socially shared everyday products that are located in public places. This project demonstrates how Object Theatre offers a broad perspective form which to explore and present product interactions....... In particular, it emphasises the understanding of a product by relating and changing perspectives, and takes into account context of use and diverse social settings....

  10. Trusted Objects

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL,PHILIP L.; PIERSON,LYNDON G.; WITZKE,EDWARD L.

    1999-10-27

    In the world of computers a trusted object is a collection of possibly-sensitive data and programs that can be allowed to reside and execute on a computer, even on an adversary's machine. Beyond the scope of one computer we believe that network-based agents in high-consequence and highly reliable applications will depend on this approach, and that the basis for such objects is what we call ''faithful execution.''

  11. Asymmetric Gepner Models III. B-L Lifting

    CERN Document Server

    Gato-Rivera, B

    2010-01-01

    In the same spirit as heterotic weight lifting, B-L lifting is a way of replacing the superfluous and ubiquitous U(1)_{B-L} with something else with the same modular properties, but different conformal weights and ground state dimensions. This method works in principle for all variants of (2,2) constructions, such as orbifolds, Calabi-Yau manifolds, free bosons and fermions and Gepner models, since it only modifies the universal SO(10) x E_8 part of the CFT. However, it can only yield chiral spectra if the ``internal" sector of the theory provides a simple current of order 5. Here we apply this new method to Gepner models. Including exceptional invariants, 86 of them have the required order 5 simple current, and 69 of these yield chiral spectra. Three family spectra occur abundantly.

  12. Variability Study of the SX Phoenicis Star BL Camelopardalis

    Institute of Scientific and Technical Information of China (English)

    Jian-Ning Fu; Chao Zhang; Kanokwan Marak; Chayan Boonyarak; Pongsak Khokhuntod; Shi-Yang Jiang

    2008-01-01

    New time-series photometric observations of BL Cam in the V band and white light were made during 2005 to 2007 at the Xinglong Station of China. The frequency analysis confirms two closely separated frequencies, 25.181 d-1 and 25.571 d-1, but the frequency of 31-32 d-1 reported in the literature was not detected in the new data. New times of maximum light were determined from both our light curves and those available on Internet, allowing a more comprehensive study of the O - C diagram, together with the times of maximum light in the literature. A new interpretation, including the period increasing before 1988 and decreasing since 1992 of BL Cam and the light-time effect in a binary system, looks plausible.

  13. Variability Study of the SX Phoenicis Star BL Camelopardalis

    Science.gov (United States)

    Fu, Jian-Ning; Zhang, Chao; Marak, Kanokwan; Boonyarak, Chayan; Khokhuntod, Pongsak; Jiang, Shi-Yang

    2008-04-01

    New time-series photometric observations of BL Cam in the V band and white light were made during 2005 to 2007 at the Xinglong Station of China. The frequency analysis confirms two closely separated frequencies, 25.181 d-1 and 25.571 d-1, but the frequency of 31-32 d-1 reported in the literature was not detected in the new data. New times of maximum light were determined from both our light curves and those available on Internet, allowing a more comprehensive study of the O-C diagram, together with the times of maximum light in the literature. A new interpretation, including the period increasing before 1988 and decreasing since 1992 of BL Cam and the light-time effect in a binary system, looks plausible.

  14. Asymmetric Gepner models III. B-L lifting

    Energy Technology Data Exchange (ETDEWEB)

    Gato-Rivera, B. [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands); Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); Schellekens, A.N., E-mail: t58@nikhef.n [NIKHEF Theory Group, Kruislaan 409, 1098 SJ Amsterdam (Netherlands); Instituto de Fisica Fundamental, CSIC, Serrano 123, Madrid 28006 (Spain); IMAPP, Radboud Universiteit, Nijmegen (Netherlands)

    2011-06-21

    In the same spirit as heterotic weight lifting, B-L lifting is a way of replacing the superfluous and ubiquitous U(1){sub B-L} with something else with the same modular properties, but different conformal weights and ground state dimensions. This method works in principle for all variants of (2,2) constructions, such as orbifolds, Calabi-Yau manifolds, free bosons and fermions and Gepner models, since it only modifies the universal SO(10)xE{sub 8} part of the CFT. However, it can only yield chiral spectra if the 'internal' sector of the theory provides a simple current of order 5. Here we apply this new method to Gepner models. Including exceptional invariants, 86 of them have the required order 5 simple current, and 69 of these yield chiral spectra. Three family spectra occur abundantly.

  15. Period doubling and Blazhko modulation in BL Herculis hydrodynamic models

    CERN Document Server

    Smolec, R

    2012-01-01

    We present the hydrodynamic BL Herculis-type models which display a long-term modulation of pulsation amplitudes and phases. The modulation is either strictly periodic or it is quasi-periodic, with the modulation period and modulation pattern varying from one cycle to the other. Such behaviour has not been observed in any BL Her variable so far, however, it is a common property of their lower luminosity siblings - RR Lyrae variables showing the Blazhko effect. These models provide a support for the recent mechanism proposed by Buchler & Kollath to explain this still mysterious phenomenon. In their model, a half-integer resonance that causes the period doubling effect, discovered recently in the Blazhko RR Lyrae stars, is responsible for the modulation of the pulsation as well. Although our models are more luminous than is appropriate for RR Lyrae stars, they clearly demonstrate, through direct hydrodynamic computation, that the mechanism can indeed be operational. Of great importance are models which show...

  16. File list: NoD.Bld.20.AllAg.BL-2 [Chip-atlas[Archive

    Lifescience Database Archive (English)

    Full Text Available NoD.Bld.20.AllAg.BL-2 hg19 No description Blood BL-2 ERX297416,ERX297448,ERX297434,...ERX297408,ERX297411,ERX297420,ERX297441 http://dbarchive.biosciencedbc.jp/kyushu-u/hg19/assembled/NoD.Bld.20.AllAg.BL-2.bed ...

  17. Period of Light Variability in BL Lac ON 231

    Indian Academy of Sciences (India)

    Xu Yun Bing; Zhang Hao Jing; Zhang Xiong; Mao Wei Ming; Dong Fu Tong

    2011-03-01

    In this paper, the authors have compiled the data of about 100 years in B-band of the BL Lac ON 231 and used this database to analyze periodicity signals in the optical light curve. Two different methods were applied: the wavelet analysis and the Discrete Correlation Function (DCF) method. We revealed the existence of periods of 13.5 years in the source variability.

  18. The Gravitational Wave Spectrum from Cosmological B-L Breaking

    CERN Document Server

    Buchmuller, Wilfried; Kamada, Kohei; Schmitz, Kai

    2013-01-01

    Cosmological B-L breaking is a natural and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase drives hybrid inflation, ending in tachyonic preheating. The decays of heavy B-L Higgs bosons and heavy neutrinos generate entropy, baryon asymmetry and dark matter and also control the reheating temperature. The different phases in the transition from inflation to the radiation dominated phase produce a characteristic spectrum of gravitational waves. We calculate the complete gravitational wave spectrum due to inflation, preheating and cosmic strings, which turns out to have several features. The production of gravitational waves from cosmic strings has large uncertainties, with lower and upper bounds provided by Abelian Higgs strings and Nambu-Goto strings, implying \\Omega_GW h^2 ~ 10^{-13} - 10^{-8}, much larger than the spectral amplitude predicted by inflation. Forthcoming gravitational wave detectors such as eL...

  19. Brain plasticity and cognitive functions after ethanol consumption in C57BL/6J mice

    Science.gov (United States)

    Stragier, E; Martin, V; Davenas, E; Poilbout, C; Mongeau, R; Corradetti, R; Lanfumey, L

    2015-01-01

    Acute or chronic administrations of high doses of ethanol in mice are known to produce severe cognitive deficits linked to hippocampal damage. However, we recently reported that chronic and moderate ethanol intake in C57BL/6J mice induced chromatin remodeling within the Bdnf promoters, leading to both enhanced brain-derived neurotrophic factor (BDNF) expression and hippocampal neurogenesis under free-choice protocol. We performed here a series of cellular and behavioral studies to analyze the consequences of these modifications. We showed that a 3-week chronic free-choice ethanol consumption in C57BL/6J mice led to a decrease in DNA methylation of the Bdnf gene within the CA1 and CA3 subfields of the hippocampus, and upregulated hippocampal BDNF signaling pathways mediated by ERK, AKT and CREB. However, this activation did not affect long-term potentiation in the CA1. Conversely, ethanol intake impaired learning and memory capacities analyzed in the contextual fear conditioning test and the novel object recognition task. In addition, ethanol increased behavioral perseveration in the Barnes maze test but did not alter the mouse overall spatial capacities. These data suggested that in conditions of chronic and moderate ethanol intake, the chromatin remodeling leading to BDNF signaling upregulation is probably an adaptive process, engaged via epigenetic regulations, to counteract the cognitive deficits induced by ethanol. PMID:26670281

  20. BL_Wiener Denoising Method for Removal of Speckle Noise in Ultrasound Image

    Directory of Open Access Journals (Sweden)

    Suhaila Sari

    2015-02-01

    Full Text Available Medical imaging techniques are extremely important tools in medical diagnosis. One of these important imaging techniques is ultrasound imaging. However, during ultrasound image acquisition process, the quality of image can be degraded due to corruption by speckle noise. The enhancement of ultrasound images quality from the 2D ultrasound imaging machines is expected to provide medical practitioners more reliable medical images in their patients’ diagnosis. However, developing a denoising technique which could remove noise effectively without eliminating the image’s edges and details is still an ongoing issue. The objective of this paper is to develop a new method that is capable to remove speckle noise from the ultrasound image effectively. Therefore, in this paper we proposed the utilization of Bilateral Filter and Adaptive Wiener Filter (BL_Wiener denoising method for images corrupted by speckle noise. Bilateral Filter is a non-linear filter effective in removing noise, while Adaptive Wiener Filter balances the tradeoff between inverse filtering and noise smoothing by removing additive noise while inverting blurring. From our simulation results, it is found that the BL_Wiener method has improved between 0.89 [dB] to 3.35 [dB] in terms of PSNR for test images in different noise levels in comparison to conventional methods.

  1. The 2003-2004 multisite photometric campaign for the β Cephei and eclipsing star 16 (EN) Lacertae with an appendix on 2 Andromedae, the variable comparison star

    Science.gov (United States)

    Jerzykiewicz, M.; Handler, G.; Daszyńska-Daszkiewicz, J.; Pigulski, A.; Poretti, E.; Rodríguez, E.; Amado, P. J.; Kołaczkowski, Z.; Uytterhoeven, K.; Dorokhova, T. N.; Dorokhov, N. I.; Lorenz, D.; Zsuffa, D.; Kim, S.-L.; Bourge, P.-O.; Acke, B.; De Ridder, J.; Verhoelst, T.; Drummond, R.; Movchan, A. I.; Lee, J.-A.; Stȩślicki, M.; Molenda-Żakowicz, J.; Garrido, R.; Kim, S.-H.; Michalska, G.; Paparó, M.; Antoci, V.; Aerts, C.

    2015-11-01

    A multisite photometric campaign for the β Cephei and eclipsing variable 16 Lacertae is reported. 749 h of high-quality differential photoelectric Strömgren, Johnson and Geneva time series photometry were obtained with 10 telescopes during 185 nights. After removing the pulsation contribution, an attempt was made to solve the resulting eclipse light curve by means of the computer program EBOP. Although a unique solution was not obtained, the range of solutions could be constrained by comparing computed positions of the secondary component in the Hertzsprung-Russell diagram with evolutionary tracks. For three high-amplitude pulsation modes, the uvy and the Geneva UBG amplitude ratios are derived and compared with the theoretical ones for spherical-harmonic degrees ℓ ≤ 4. The highest degree, ℓ = 4, is shown to be incompatible with the observations. One mode is found to be radial, one is ℓ = 1, while in the remaining case ℓ = 2 or 3. The present multisite observations are combined with the archival photometry in order to investigate the long-term variation of the amplitudes and phases of the three high-amplitude pulsation modes. The radial mode shows a non-sinusoidal variation on a time-scale of 73 yr. The ℓ = 1 mode is a triplet with unequal frequency spacing, giving rise to two beat-periods, 720.7 d and 29.1 yr. The amplitude and phase of the ℓ = 2 or 3 mode vary on time-scales of 380.5 d and 43 yr. The light variation of 2 And, one of the comparison stars, is discussed in the appendix.

  2. LACERTA I AND CASSIOPEIA III. TWO LUMINOUS AND DISTANT ANDROMEDA SATELLITE DWARF GALAXIES FOUND IN THE 3{pi} PAN-STARRS1 SURVEY

    Energy Technology Data Exchange (ETDEWEB)

    Martin, Nicolas F.; Laevens, Benjamin P. M. [Observatoire astronomique de Strasbourg, Universite de Strasbourg, CNRS, UMR 7550, 11 rue de l' Universite, F-67000 Strasbourg (France); Slater, Colin T.; Bell, Eric F. [Department of Astronomy, University of Michigan, 500 Church St., Ann Arbor, MI 48109 (United States); Schlafly, Edward F.; Morganson, Eric; Rix, Hans-Walter [Max-Planck-Institut fuer Astronomie, Koenigstuhl 17, D-69117 Heidelberg (Germany); Bernard, Edouard J.; Ferguson, Annette M. N. [Institute for Astronomy, University of Edinburgh, Royal Observatory, Blackford Hill, Edinburgh EH9 3HJ (United Kingdom); Finkbeiner, Douglas P. [Harvard-Smithsonian Center for Astrophysics, 60 Garden Street, Cambridge, MA 02138 (United States); Burgett, William S.; Chambers, Kenneth C.; Hodapp, Klaus W.; Kaiser, Nicholas; Kudritzki, Rolf-Peter; Magnier, Eugene A.; Morgan, Jeffrey S.; Tonry, John L.; Wainscoat, Richard J. [Institute for Astronomy, University of Hawaii at Manoa, Honolulu, HI 96822 (United States); Price, Paul A., E-mail: nicolas.martin@astro.unistra.fr [Department of Astrophysical Sciences, Princeton University, Princeton, NJ 08544 (United States)

    2013-07-20

    We report the discovery of two new dwarf galaxies, Lacerta I/Andromeda XXXI (Lac I/And XXXI) and Cassiopeia III/Andromeda XXXII (Cas III/And XXXII), in stacked Pan-STARRS1 r{sub P1}- and i{sub P1}-band imaging data. Both are luminous systems (M{sub V} {approx} -12) located at projected distances of 20. Degree-Sign 3 and 10. Degree-Sign 5 from M31. Lac I and Cas III are likely satellites of the Andromeda galaxy with heliocentric distances of 756{sup +44}{sub -28} kpc and 772{sup +61}{sub -56} kpc, respectively, and corresponding M31-centric distances of 275 {+-} 7 kpc and 144{sup +6}{sub -4} kpc. The brightest of recent Local Group member discoveries, these two new dwarf galaxies owe their late discovery to their large sizes (r{sub h} = 4.2{sup +0.4}{sub -0.5} arcmin or 912{sup +124}{sub -93} pc for Lac I; r{sub h} = 6.5{sup +1.2}{sub -1.0} arcmin or 1456 {+-} 267 pc for Cas III) and consequently low surface brightness ({mu}{sub 0} {approx} 26.0 mag arcsec{sup -2}), as well as to the lack of a systematic survey of regions at large radii from M31, close to the Galactic plane. This latter limitation is now alleviated by the 3{pi} Pan-STARRS1 survey, which could lead to the discovery of other distant Andromeda satellite dwarf galaxies.

  3. Searching for Rare Celestial Objects Automatically from Stellar Spectra of the Sloan Digital Sky Survey Data Release Eight%在 SDSS DR8恒星光谱中自动搜寻稀有天体

    Institute of Scientific and Technical Information of China (English)

    司建敏; 罗阿理; 吴福朝; 吴毅红

    2015-01-01

    There are many valuable rare and unusual objects in spectra dataset of Sloan Digital Sky Survey (SDSS)Data Release eight (DR8),such as special white dwarfs (DZ,DQ,DC),carbon stars,white dwarf main-sequence binaries (WDMS),cata-clysmic variable (CV)stars and so on,so it is extremely significant to search for rare and unusual celestial objects from massive spectra dataset.A novel algorithm based on Kernel dense estimation and K-nearest neighborhoods (KNN)has been presented, and applied to search for rare and unusual celestial objects from 546 383 stellar spectra of SDSS DR8.Their densities are esti-mated using Gaussian kernel density estimation,the top 5 000 spectra in descend order by their densities are selected as rare ob-jects,and the top 300 000 spectra in ascend order by their densities are selected as normal objects.Then,KNN were used to classify the rest objects,and simultaneously K nearest neighbors of the 5 000 rare spectra are also selected as rare objects.As a result,there are totally 21 193 spectra selected as initial rare spectra,which include error spectra caused by deletion,redden, bad calibration,spectra consisting of different physically irrelevant components,planetary nebulas,QSOs,special white dwarfs (DZ,DQ,DC),carbon stars,white dwarf main-sequence binaries (WDMS),cataclysmic variable (CV)stars and so on.By cross identification with SIMBAD,NED,ADS and major literature,it is found that three DZ white dwarfs,one WDMS,two CVs with company of G-type star,three CVs candidates,six DC white dwarfs,one DC white dwarf candidate and one BL Lacer-tae (BL lac)candidate are our new findings.We also have found one special DA white dwarf with emission lines of CaⅡ triple and MgⅠ,and one unknown object whose spectrum looks like a late M star with emission lines and its image looks like a galaxy or nebula.%SDSS DR8海量光谱中包含许多有研究价值的稀有天体,如特殊白矮星(DZ,DQ,DC)、碳星、白矮主序双星、激变变星等

  4. Fashion Objects

    DEFF Research Database (Denmark)

    Andersen, Bjørn Schiermer

    2009-01-01

    This article attempts to create a framework for understanding modern fashion phenomena on the basis of Durkheim's sociology of religion. It focuses on Durkheim's conception of the relation between the cult and the sacred object, on his notion of 'exteriorisation', and on his theory of the social...... symbol in an attempt to describe the peculiar attraction of the fashion object and its social constitution. However, Durkheim's notions of cult and ritual must undergo profound changes if they are to be used in an analysis of fashion. The article tries to expand the Durkheimian cult, radically enlarging...... -- an outline which at the same time indicates the need for transformations of the Durkheimian model on decisive points. Thus, thirdly, it returns to Durkheim and undertakes to develop his concepts in a direction suitable for a sociological theory of fashion. Finally, it discusses the theoretical implications...

  5. Objective becoming

    CERN Document Server

    Skow, Bradford

    2015-01-01

    Bradford Skow presents an original defense of the 'block universe' theory of time, often said to be a theory according to which time does not pass. Along the way, he provides in-depth discussions of alternative theories of time, including those in which there is 'robust passage' of time or 'objective becoming': presentism, the moving spotlight theory of time, the growing block theory of time, and the 'branching time' theory of time. Skow explains why the moving spotlight theory is the best of these arguments, and rebuts several popular arguments against the thesis that time passes. He surveys the problems that the special theory of relativity has been thought to raise for objective becoming, and suggests ways in which fans of objective becoming may reconcile their view with relativistic physics. The last third of the book aims to clarify and evaluate the argument that we should believe that time passes because, somehow, the passage of time is given to us in experience. He isolates three separate arguments thi...

  6. Surviving Objects

    OpenAIRE

    Murjas, Teresa

    2012-01-01

    Surviving Objects (2012) is a devised multi-media practice-as-research performance based on extensive interviews conducted with my elderly mother and recorded on a hand-held device. Our conversations concern her experiences as a child refugee following violent deportation by the Soviet Army from Eastern Poland to Siberia (1941), and her subsequent route, via Persia, to a British-run refugee camp in Northern Rhodesia, where she remained for 6 years before arriving in the UK. In order to aid my...

  7. Functional Analysis of the Lactobacillus casei BL23 Sortases

    Science.gov (United States)

    Muñoz-Provencio, Diego; Rodríguez-Díaz, Jesús; Collado, María Carmen; Langella, Philippe; Bermúdez-Humarán, Luis G.

    2012-01-01

    Sortases are a class of enzymes that anchor surface proteins to the cell wall of Gram-positive bacteria. Lactobacillus casei BL23 harbors four sortase genes, two belonging to class A (srtA1 and srtA2) and two belonging to class C (srtC1 and srtC2). Class C sortases were clustered with genes encoding their putative substrates that were homologous to the SpaEFG and SpaCBA proteins that encode mucus adhesive pili in Lactobacillus rhamnosus GG. Twenty-three genes encoding putative sortase substrates were identified in the L. casei BL23 genome with unknown (35%), enzymatic (30%), or adhesion-related (35%) functions. Strains disrupted in srtA1, srtA2, srtC1, and srtC2 and an srtA1 srtA2 double mutant were constructed. The transcription of all four sortase encoding genes was detected, but only the mutation of srtA1 resulted in a decrease in bacterial surface hydrophobicity. The β-N-acetyl-glucosaminidase and cell wall proteinase activities of whole cells diminished in the srtA1 mutant and, to a greater extent, in the srtA1 srtA2 double mutant. Cell wall anchoring of the staphylococcal NucA reporter protein fused to a cell wall sorting sequence was also affected in the srtA mutants, and the percentages of adhesion to Caco-2 and HT-29 intestinal epithelial cells were reduced for the srtA1 srtA2 strain. Mutations in srtC1 or srtC2 result in an undetectable phenotype. Together, these results suggest that SrtA1 is the housekeeping sortase in L. casei BL23 and SrtA2 would carry out redundant or complementary functions that become evident when SrtA1 activity is absent. PMID:23042174

  8. Effect of Crossing C57BL/6 and FVB Mouse Strains on Basal Cytokine Expression

    Directory of Open Access Journals (Sweden)

    Agata Szade

    2015-01-01

    Full Text Available C57BL/6 is the most often used laboratory mouse strain. However, sometimes it is beneficial to cross the transgenic mice on the C57BL/6 background to the other strain, such as FVB. Although this is a common strategy, the influence of crossing these different strains on homeostatic expression of cytokines is not known. Here we have investigated the differences in the expression of selected cytokines between C57BL/6J and C57BL/6JxFVB mice in serum and skeletal muscle. We have found that only few cytokines were altered by crossing of the strains. Concentrations of IL5, IL7, LIF, MIP-2, and IP-10 were higher in serum of C57BL/6J mice than in C57BL/6JxFVB mice, whereas concentration of G-CSF was lower in C57BL/6J. In the skeletal muscle only the concentration of VEGF was higher in C57BL/6J mice than in C57BL/6JxFVB mice. Concluding, the differences in cytokine expression upon crossing C57BL/6 and FVB strain in basal conditions are not profound.

  9. Objective thermomechanics

    CERN Document Server

    Fülöp, Tamás

    2015-01-01

    An irreversible thermodynamical theory of solids is presented where the kinematic quantities are defined in an automatically objective way. Namely, auxiliary elements like reference frame, reference time and reference configuration are avoided by formulating the motion of the continuum on spacetime directly, utilizing the Weyl-Matolcsi description of spacetime. This restricts the range of definable kinematic quantities heavily. Solids are distinguished from fluids by possessing not only an instantaneous metric tensor but a relaxed metric, too, that represents the natural geometric structure of the solid. The comparison of the instantaneous metric to the relaxed one is the basis of the definition of the elastic state variable, the elastic deformedness tensor. Thermal expansion is conceived as the temperature dependence of the relaxed metric. As opposed to this reversible type of change, plasticity means an irreversible change in the relaxed metric, and is describable via a plastic change rate tensor. The relat...

  10. Capric Acid Reduces Body Weight in C57BL/6J Mice Fed a High Fat Diet

    Institute of Scientific and Technical Information of China (English)

    Ying-hua LIU; Yong ZHANG; Qing XU; Xin-sheng ZHANG; Jin WANG; Xiao-ming YU; Xue-yan YANG; Chang-yong XUE

    2014-01-01

    Objective To compare the body weight reducing effect of two medium-chain fatty acids (MCFA), capric acid and caprylic acid, and the potential underlying mechanisms in C57BL/6J mice fed a high fat diet.Methods Obese C57BL/6J mice were developed on a high-fat diet containing 2% caprylic acid (C8:0), 2% capric acid (C10:0), or 2% oleic acid (C18:1). Body weight and diet intake were monitored twice a week. After 8 weeks of feeding, body fat composition and the protein or mRNA expression of lipolysis-related genes in the white adipose tissue (WAT) were analyzed.Results In the capric acid group, significant reductions were observed in body weight gain, Lee's index, BMI, and epididymal adipose tissue weight, while increased levels of adipose triglyceride lipase (ATGL), hormone-sensitive lipase (HSL), cyclic adenosine monophosphate (cAMP) and beta 3 adrenergic receptor (β3-AR) were found in the adipose tissue, compared to the oleic acid group. No significant differences in these parameters were found between caprylic acid and oleic acid groups.Conclusion Capric acid, but not caprylic acid, is effective in reducing body weight in obese C57BL/6J mice,possibly due to up-regulation of β3-AR, ATGL, and HSL in WAT.

  11. The labeling of C57BL/6j derived embryonic stem cells with enhanced green fluorescent protein

    Institute of Scientific and Technical Information of China (English)

    滕路; 张崇本; 尤洁芳; 尚克刚; 顾军

    2003-01-01

    Objective To labele MESPU35, a embryonic stem (ES) cell line derived from C57BL/6j mouse, with enhanced green fluorescent protein (EGFP) for further application.Methods The EGFP gene was controlled by the hybrid CA promoter/enhancer (CMV enhancer/ chicken beta-actin promoter/ beta-actin intron) to construct the vector of the transgene, pCA-EGFP. The vector was transfected into MESPU35 by electroporation.Results We generated EGFP expressing ES cells demonstrating normal properties. The green fluorescence of EGFP expressing cells was maintained in propagation of the ES cells for more than 30 passages as well as in differentiated cells. Cultured in suspension, the "green" ES cells aggregated, and formed embryoid bodies maintaining the green fluorescence at varying developmental stages. The "green" embryoid bodies could expand and differentiate into various types of cells, exhibiting ubiquitous green fluorescence. Conclusions The hybrid CA promoter/enhancer used to control the EGFP expressing ES cells, resulted in more intense and ubiquitous activity. The EGFP transfected cells yield bright green fluorescence, which can be visualized in real time and in situ. In addition, the ES cells, MESPU35, are derived from C57BL/6j mice, which are the most widely used in oncology, physiology and genetics. Compared to 129 substrains, C57BL/6j mice avoid a number of potential problems apparent in the other strains.

  12. Long-term artificial sweetener acesulfame potassium treatment alters neurometabolic functions in C57BL/6J mice.

    Directory of Open Access Journals (Sweden)

    Wei-na Cong

    Full Text Available With the prevalence of obesity, artificial, non-nutritive sweeteners have been widely used as dietary supplements that provide sweet taste without excessive caloric load. In order to better understand the overall actions of artificial sweeteners, especially when they are chronically used, we investigated the peripheral and central nervous system effects of protracted exposure to a widely used artificial sweetener, acesulfame K (ACK. We found that extended ACK exposure (40 weeks in normal C57BL/6J mice demonstrated a moderate and limited influence on metabolic homeostasis, including altering fasting insulin and leptin levels, pancreatic islet size and lipid levels, without affecting insulin sensitivity and bodyweight. Interestingly, impaired cognitive memory functions (evaluated by Morris Water Maze and Novel Objective Preference tests were found in ACK-treated C57BL/6J mice, while no differences in motor function and anxiety levels were detected. The generation of an ACK-induced neurological phenotype was associated with metabolic dysregulation (glycolysis inhibition and functional ATP depletion and neurosynaptic abnormalities (dysregulation of TrkB-mediated BDNF and Akt/Erk-mediated cell growth/survival pathway in hippocampal neurons. Our data suggest that chronic use of ACK could affect cognitive functions, potentially via altering neuro-metabolic functions in male C57BL/6J mice.

  13. Probing BL Lac and Cluster Evolution via a Wide-angle, Deep X-ray Selected Sample

    Science.gov (United States)

    Perlman, E.; Jones, L.; White, N.; Angelini, L.; Giommi, P.; McHardy, I.; Wegner, G.

    1994-12-01

    The WARPS survey (Wide-Angle ROSAT Pointed Survey) has been constructed from the archive of all public ROSAT PSPC observations, and is a subset of the WGACAT catalog. WARPS will include a complete sample of >= 100 BL Lacs at F_x >= 10(-13) erg s(-1) cm(-2) . A second selection technique will identify ~ 100 clusters at 0.15 = 0.304 +/- 0.062 for XBLs but = 0.60 +/- 0.05 for RBLs. Models of the X-ray luminosity function (XLF) are also poorly constrained. WARPS will allow us to compute an accurate XLF, decreasing the error bars above by over a factor of two. We will also test for low-luminosity BL Lacs, whose non-thermal nuclear sources are dim compared to the host galaxy. Browne and Marcha (1993) claim the EMSS missed most of these objects and is incomplete. If their predictions are correct, 20-40% of the BL Lacs we find will fall in this category, enabling us to probe the evolution and internal workings of BL Lacs at lower luminosities than ever before. By removing likely QSOs before optical spectroscopy, WARPS requires only modest amounts of telescope time. It will extend measurement of the cluster XLF both to higher redshifts (z>0.5) and lower luminosities (LX<1x10(44) erg s(-1) ) than previous measurements, confirming or rejecting the 3sigma detection of negative evolution found in the EMSS, and constraining Cold Dark Matter cosmologies. Faint NELGs are a recently discovered major contributor to the X-ray background. They are a mixture of Sy2s, starbursts and galaxies of unknown type. Detailed classification and evolution of their XLF will be determined for the first time.

  14. Exploring the magnetic field configuration in BL Lac using GMVA

    CERN Document Server

    Rani, B; Hodgson, J; Koyama, S; Zensus, J A; Fuhrmann, L; Marscher, A P; Jorstad, S G

    2016-01-01

    The high radio frequency polarization imaging of non-thermal emission from active galactic nuclei (AGN) is a direct way to probe the magnetic field strength and structure in the immediate vicinity of supermassive black holes (SMBHs) and is crucial in testing the jet-launching scenario. To explore the the magnetic field configuration at the base of jets in blazars, we took advantage of the full polarization capabilities of the Global Millimeter VLBI Array (GMVA). With an angular resolution of $\\sim$50 micro-arcseconds ($\\mu$as) at 86 GHz, one could resolve scales up to $\\sim$450 gravitational radii (for a 10$^9$ solar mass black hole at a redshift of 0.1). We present here the preliminary results of our study on the blazar BL~Lac. Our results suggest that on sub-mas scales the core and the central jet of BL Lac are significantly polarized with two distinct regions of polarized intensity. We also noted a great morphological similarity between the 7mm/3mm VLBI images at very similar angular resolution.

  15. 蓝氏贾第鞭毛虫C57BL/6N小鼠动物模型的建立%Establishment of a C57BL/6N mouse model of giardiasis

    Institute of Scientific and Technical Information of China (English)

    卢思奇; 王凤云; 罗晓冰; 陈小宁

    2002-01-01

    目的建立人源蓝氏贾第鞭毛虫C57BL/6N小鼠动物感染模型.方法用分离自河北和江苏两地蓝氏贾第鞭毛虫感染者的包囊(河北株,CD和江苏株,XZ)分别感染两组C57BL/6N小鼠,收集受染鼠粪便,用蔗糖梯度离心法分离纯化包囊,计算排囊数量 ,分析排囊规律;观察小肠病理组织学改变.结果 C57BL/6N小鼠对此2 株蓝氏贾第鞭毛虫具有很高的易感性,接受具有活力的1×104个包囊/只的36只小鼠,均获得感染,其中呈间歇性排囊者为32只(88.9%),连续性排囊者4只 (11.1%).排囊潜伏期为接种后第3d,高峰期为第7d.2小时所排粪便含包囊数最高可达2. 3×107个/g粪. 小肠粘膜出现表面分泌物增加,间质充血、水肿,炎性细胞浸润,粘膜坏死脱落等病理变化.结论 C57BL/6N小鼠可用做建立蓝氏贾第鞭毛虫感染的良好动物模型.%Objective To establish a C57BL/6N mouse model infected with Giardia lamblia (G. Lamblia) isolates from human origin.Method Two groups of C57BL/6N mouse were inoculated wit h purified cysts of two G. Lamblia isolates (CD and XZ) by gavage separately. Patterns and curves of cyst excretion of the infected mice were observed and sum marized. Histopathological changes of the small intestines of the infected mice were observed.Results Thirty-six mice receiving 1×104 cysts each were all infected. The C57BL/6N mouse showed high susceptibility to G. Lamb lia infection. There was no notable distinction between the two groups of the mice infected by the cysts of CD and XZ isolates. Cyst excretion occurred with int ermittence. Of 36 infected mice, 32 (89%) passed cysts intermittently and 4 (11 %) others persistently. The latent period of cyst excretion was 0-3 days p.I. (post-inoculation). The interruption of cyst excretion ranged from 12 to 20d ays p.I. The fastigium of the cyst excretion was on day 6 p.I. The peak count of the cysts passed during a 2h collection period was 2.3×107 /g fecal sp ecimen

  16. [Influence of temperature on the rate of spermatogenesis, duration of spermatogenic activity and development of secondary sex characteristics in the wall-lizard, Lacerta muralis L. (Reptilia, Lacertidae)].

    Science.gov (United States)

    Joly, J; Saint Girons, H

    1975-01-01

    A series of experiments was carried out primarily between the 22nd of March and the 27th of June, on 60 Lacerta muralis maintained either under semi-natural conditions in large enclosures or in constant-temperature cabinets maintained at 17.5 degrees C, 20 degrees C, 22.5 degrees C and 27.5 degrees C with a natural photoperiod. Following an injection of tritiated thymidine, the animals were sacrificed at regular intervals and the rate of spermatogenesis was deduced from the progression of the radioactive front in the seminiferous epithelium. The following results were obtained: 1. The rate of spermatogenesis is temperature dependent and increases by a factor of approximately 1.2 per degree centigrade between 17.5 and 27.5 degrees C. The rate is seven times greater at 27.5 degrees C than at 17.5 degrees C. 2. Under semi-natural conditions the interval leptotene-spermatozooid lasts 70 days, slightly less than that found at a constant temperature of 22.5 degrees C. 3. Under semi-natural conditions the rate of spermatogenesis was similar to that in August-September, April-May and May-June which indicates that the lizards were able to maintain their body temperature at an equivalent level by behavioural temperature regulation during the greater part of their activity period. 4. Under semi-natural conditions, or at temperatures in excess of 22 degrees C, spermiogenesis lasts 1.8 times as long as meiosis. 5. At constant temperatures lower than 21 degrees C the development of the cellular lineage is aressted at the young spermatid stage. 6. Constant temperatures between 17.5 and 22.5 degrees C had no effect on the time of involution of the testis at the start of summer. 7. At low constant temperatures, secondary sexual characteristics regress before the usual time: after 4 weeks at 20 degrees C and after 8 weeks at 17.5 degrees C. An expected regression after 8 weeks produced after exposure to a temperature of 22.5 degrees C is probably due to factors other than

  17. 委中穴区刮痧对本经同侧经脉线上皮肤微循环血流灌注量的影响%Effects of Weizhong (BL 40) Area Scraping on Blood Perfusion Level of the Skin Microcirculation of Qihaishu (BL 24) Region at the Ipsilateral Back of the Volunteer's Body

    Institute of Scientific and Technical Information of China (English)

    徐青燕; 杨金生; 杨莉; 王莹莹; 刘秀兰

    2013-01-01

    目的:观察正常人体委中穴区刮痧前后经脉线上皮肤微循环血流灌注量的变化,探讨穴区刮痧疗效的作用机制.方法:在10例健康人体膀胱经委中穴区刮痧,应用激光多普勒血流成像仪,观察刮痧前至刮痧后90 min内,委中穴区及本经同侧经脉线上气海俞区域的皮肤微循环血流灌注量变化情况,利用LDPI图像软件处理相关数据,进行组内比较和相关性统计学分析.结果:委中穴区刮痧后即刻至90 min各时间段血流灌注量与刮痧前相比均显著升高(P<0.001,P<0.01);委中穴区刮痧后15、60、90 min时,本经同侧经脉线气海俞穴区皮肤血流灌注量与刮痧前相比均有不同程度升高(P<0.05).委中穴区与气海俞穴区之间血流灌注量变化存在正相关关系(P<0.05).结论:穴区刮痧可明显增加本经经脉线上皮肤微循环血流灌注量,改善皮肤微循环,促进沿经组织新陈代谢,是刮痧活血化瘀、疏通经络以及畅通气血运行的机制之一.%Objective To observe the effect of Guasha (scraping) of Weizhong (BL 40) on the cutaneous blood perfusion of Qihaishu (BL 24) region of the Bladder Meridian on the back. Methods Ten healthy volunteer subjects were recuited in the present study. Weizhong (BL 40, at the politeal fossa) area was repeatedly scraped till regional flush using a cornu bubali scraping plate for 5 min after applying scraping oil to the regional skin. Then blood perfusion levels of the skin microcirculation a-round Weizhong (BL 40) and Qihaishu (BL 24) regions on the ipsilateral back were detected using a Laser Doppler flowmetry (PeriScan PIME ). Results Following scraping Weizhong (BL 40) region, the cutaneous blood perfusion levels in the stimulated region were increased significantly at the time-points of 0, 15, 60 and 90 min after scraping ( P<0. 001, P<0. 01), while those of Qihaishu (BL 24) area at the lumbar part also showed a remarkable increase 15, 60 and 90 min

  18. The estimations of four basic parameters for gamma-ray loud blazars

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Yu-Hai Yuan; Yi Liu; Jing-Yi Zhang; Yi-Ping Qin; Hua Liu; Yong Huang; Jiang-He Yang; Hong-Guang Wang; Jiang-Shui Zhang

    2009-01-01

    The method used in our previous papers is adopted to estimate four basic pa-rameters (the central black hole mass (M), the boosting factor (or Doppler factor) (δ), the (d)) for 59 γ-ray loud blazars (20 BL Lacertae objects and 39 fiat spectrum radio quasars).The central black hole masses estimated for this sample are in a range of from 107 M⊙to 109 M⊙. In the case of black hole mass, there is no clear difference between BL Lacertae objects and flat spectrum radio quasars, which is consistent with the previous results sug-gesting that the central black hole masses do not play an important role in the evolutionary sequence of blazars.

  19. Cornu cervi pantotrichum Pharmacopuncture Solution Facilitate Hair Growth in C57BL/6 Mice

    Directory of Open Access Journals (Sweden)

    Seon-Yong Lee

    2016-06-01

    Full Text Available Objectives: Cornu cervi pantotrichum (CCP has been widely used in Korean and China, as an anti-fatigue, anti-aging, and tonic agent to enhance the functions of the reproductive and the immune systems. Because CCP has various growth factors that play important roles in the development of hair follicles, we examined whether CCP pharmacopuncture solution (CCPPS was capable of promoting hair growth in an animal model. Methods: One day after hair depilation, CCPPS were topically applied to the dorsal skin of C57BL/6 mice once a day for 15 days. Hair growth activity was evaluated by using macro- and microscopic observations. Dorsal skin tissues were stained with hematoxylin and eosin. Expressions of bromodeoxyuridine (BrdU, proliferating cell nuclear antigen (PCNA, and fibroblast growth factor (FGF-7 were examined by using immunohistochemical staining. A reverse transcription polymerase chain reaction (RT-PCR analysis was also conducted to measure the messenger RNA (mRNA expression of FGF-7. Results: CCPPS induced more active hair growth than normal saline. Histologic analysis showed enlargement of the dermal papilla, elongation of the hair shaft, and expansion of hair thickness in CCPPS treated mice, indicating that CCPPS effectively induced the development of anagen. CCPPS treatment markedly increased the expressions of BrdU and PCNA in the hair follicles of C57BL/6 mice. In addition, CCPPS up regulated the expression of FGF-7, which plays an important role in the development of hair follicles. Conclusion: These results reveal that CCPPS facilitates hair re-growth by proliferation of hair follicular cells and up-regulation of FGF-7 and suggest that CCPPS can potentially be applied as an alternative treatment for patients with alopecia.

  20. AMPK基因在C57BL/6J小鼠糖脂代谢中的作用%The role of AMPK gene in glucose and lipid metabolism in C57BL/6J mice

    Institute of Scientific and Technical Information of China (English)

    张远远; 刘星; 何君; 姜晓亮; 杨志伟

    2011-01-01

    Objective To investigate the role of AMPK gene in regulating glucose and lipid metabolism. Methods We used 24 C57BL/6J mice and 24 AMPK gene knock-out mice (AMPK-KO) at five weeks old, fed with normal diet (ND)and high-glucose-fat diet (HFD)separately for 12 weeks. The blood glucose and fasting blood glucose were measured every 2 weeks. The capability of glucose tolerance was measured before the experiment was terminated. The blood/serum biochemical indicators, the enzyme activities and glycogen content were observed after 12-week's feeding. The expressions of P-AMPK, GluT-4 and PPARγ proteins in liver were detected. Result The blood glucose level, fasting blood glucose, the peak glucose of OGTT, the level of TC, LDL and HbA1 c, the activity of G6PD and GSK in serum and the expression of PPARγ proteins were higher in liver in AMPK-KO mice than in C57BL/6J control mice (P<0. 05). The level of hepatic and muscle's glycogen, the activity of lipase and GK, the expression of P-AMPK and GIuT-4 proteins were lower in AMPK-KO mice than in control C57BL/6J mice (F<0. 05). Conclusion The AMPK gene plays an important role in the pathogenesis of type 2 diabetes through regulating the glucose and lipid metabolism in C57BL/6J mice.%目的 研究腺苷酸活化蛋白激酶( AMPK)基因在C57BL/6J小鼠糖脂代谢中的作用.方法 分别取5周龄AMPK基因敲除(AMPK-KO)小鼠和C57BL/6J对照小鼠各24只,分为正常饲料(ND)喂养和高脂高糖饲料(HFD)喂养两组.喂养12周,每两周测定小鼠禁食4h血糖(FBG),实验结束前行口服糖耐量实验(OGTT),解剖取样,检测血生化指标、脂酶活性及相关蛋白的表达. 结果 AMPK-KO小鼠血糖、TC、LDL-C、HbA1 c、6-磷酸葡萄糖脱氢酶(G6PD)活性、糖原合成酶激酶(GSK)活性、肝脏PPARγ蛋白表达量明显高于对照小鼠(P<0.05);其胰岛素含量、肝糖原含量、肌糖原含量、肝脂酶(HL)活性、脂蛋白酯酶(LPL)活性、总脂酶活性、葡萄糖激酶(GK)

  1. Differential Localization of Pain-Related and Pain-Unrelated Neural Responses for Acupuncture at BL60 Using BOLD fMRI

    Directory of Open Access Journals (Sweden)

    Na-Hee Kim

    2013-01-01

    Full Text Available The objective of this study was to differentiate between pain-related and pain-unrelated neural responses of acupuncture at BL60 to investigate the specific effects of acupuncture. A total of 19 healthy volunteers were evaluated. fMRI was performed with sham or verum acupuncture stimulation at the left BL60 before and after local anesthesia. To investigate the relative BOLD signal effect for each session, a one-sample t-test was performed for individual contrast maps, and a paired t-test to investigate the differences between the pre- and post-anesthetic signal effects. Regarding verum acupuncture, areas that were more activated before local anesthesia included the superior, middle, and medial frontal gyri, inferior parietal lobule, superior temporal gyrus, thalamus, middle temporal gyrus, cingulate gyrus, culmen, and cerebellar tonsil. The postcentral gyrus was more deactivated before local anesthesia. After local anesthesia, the middle occipital gyrus, inferior temporal gyrus, postcentral gyrus, precuneus, superior parietal lobule, and declive were deactivated. Pre-anesthetic verum acupuncture at BL60 activated areas of vision and pain transmission. Post-anesthetic verum acupuncture deactivated brain areas of visual function, which is considered to be a pain-unrelated acupuncture response. It indicates that specific effects of acupoint BL60 are to control vision sense as used in the clinical setting.

  2. A Weakened Form of BL-Algebra%BL代数的一种弱化形式

    Institute of Scientific and Technical Information of China (English)

    周建仁; 吴洪博

    2014-01-01

    在对 BL-代数及其相关逻辑代数研究的基础上,通过加强 MTL-代数条件的方法建立BL-代数的一种弱化形式---WBL-代数,并给出 WBL-代数结构的实例;证明 BL-代数是WBL-代数,并通过实例说明 WBL-代数是BL-代数的真弱化形式,且是 MTL-代数的真加强形式;在MTL-代数的基础上给出 WBL-代数的一些特征定理。%On the basic of BL-algebra and other related logic algebras,a weaker logic algebric system than BL-algebra---WBL-algebra was established by strengthening the conditions of MTL-algebra and examples of WBL-algebra were given.It has been proved that BL-algebra is WBL-algebra and WBL-algebra is the truth weakening form of BL-algebra and the truth strengthening form of MTL-algebra.Some characteristic theorems of WBL-algebra were given based on MTL-algebra.

  3. Blæksprutter beskyttes på niveau med hvirveldyr

    DEFF Research Database (Denmark)

    Alstrup, Aage Kristian Olsen

    2015-01-01

    beskyttede. Et af de bedst studerede hvirvelløse dyr er blæksprutten, navnlig Octopus vulgaris. Vores viden om nerveimpulsen udbredelse stammer netop fra blæksprutter, da de har meget store nerveceller, der let lader sig undersøge. De to forskere fik faktisk Nobelprisen i 1963 for opdagelsen. Siden da har...

  4. $Z^\\prime_{BL}$ portal dark matter and LHC Run-2 results

    CERN Document Server

    Okada, Nobuchika

    2016-01-01

    We consider a concise dark matter scenario in the minimal gauged $B-L$ extension of the Standard Model (SM), where the global $B-L$ (baryon number minus lepton number) symmetry in the SM is gauged, and three generations of right-handed neutrinos and a $B-L$ Higgs field are introduced. Associated with the $B-L$ gauge symmetry breaking by a VEV of the $B-L$ Higgs field, the seesaw mechanism for generating the neutrino mass is automatically implemented after the electroweak symmetry breaking in the SM. In this model context, we introduce a $Z_2$-parity and assign an odd parity for one right-handed neutrino while even parities for the other fields. Therefore, the dark matter candidate is identified as the right-handed Majorana neutrino with odd $Z_2$ parity, keeping the minimality of the particle content intact. When the dark matter particle communicates with the SM particles mainly through the $B-L$ gauge boson ($Z^\\prime_{BL}$ boson), its relic abundance is determined by only three free parameters, the $B-L$ ga...

  5. The relationship between the radio core dominance parameter and the spectral index in different classes of extragalactic radio sources

    Institute of Scientific and Technical Information of China (English)

    Jun-Hui Fan; Jiang-He Yang; Jing Pan; Tong-Xu Hua

    2011-01-01

    Active galactic nuclei (AGNs) have two major classes,namely radio loud AGNs and radio quiet AGNs.A small subset of the radio-loud AGNs is called blazars,which display extreme observational properties,such as rapid variability,high Iuminosity,high and variable polarization,and superluminal motion.All of those observational properties are probably due to a relativistic beaming effect with the jet pointing close to the line of sight.Observations suggest that the orientation can be expressed by a core-dominance parameter,R.The R,to some extent,is associated with the beaming effect.Blazars are believed to be unified with Fanaroff & Riley type I/Ⅱ (FRI/Ⅱ)radio galaxies.In this work,we collected relevant observations from the literature for a sample of 1223 AGNs including 77 BL Lacertae objects,495 quasars,460 galaxies,119 FRs and 72 unidentified sources,and calculated the core-dominance parameters and spectral indexes,discussed the relationship between the two parameters,and gave some discussions.Our analysis suggests that the core-dominance parameters in BL Lacertae objects are larger than those in quasars and galaxies,and the radio spectral indexes in BL Lacertae objects are lower than those in quasars and galaxies.We also found that the core-dominance parameter-spectral index correlation exists for a large sample presented in this work,which may come from a relativistic beaming effect.

  6. VERITAS observations of the BL Lac 1ES 1218+304

    CERN Document Server

    Acciari, V A; Arlen, T; Beilicke, M; Benbow, W; Bradbury, S M; Buckley, J H; Bugaev, V; Butt, Y; Byrum, K L; Celik, O; Cesarini, A; Ciupik, L; Chow, Y C K; Cogan, P; Colin, P; Cui, W; Daniel, M K; Ergin, T; Falcone, A D; Fegan, S J; Finley, J P; Fortin, P; Fortson, L F; Furniss, A; Gillanders, G H; Grube, J; Guenette, R; Gyuk, G; Hanna, D; Hays, E; Holder, J; Horan, D; Hui, C M; Humensky, T B; Imran, A; Kaaret, Philip; Karlsson, N; Kertzman, M; Kieda, D B; Kildea, J; Konopelko, A; Krawczynski, H; Krennrich, F; Lang, M J; Le Bohec, S; Maier, G; McCann, A; McCutcheon, M; Moriarty, P; Mukherjee, R; Nagai, T; Niemiec, J; Ong, R A; Pandel, D; Perkins, J S; Pohl, M; Quinn, J; Ragan, K; Reyes, L C; Reynolds, P T; Rose, H J; Schroedter, M; Sembroski, G H; Smith, A W; Steele, D; Swordy, S P; Toner, J A; Valcarcel, L; Vasilev, V V; Wagner, R; Wakely, S P; Ward, J E; Weekes, T C; Weinstein, A; White, R J; Williams, D A; Wissel, S A; Wood, M; Zitzer, B

    2009-01-01

    The VERITAS collaboration reports the detection of very-high-energy (VHE) gamma-ray emission from the high-frequency-peaked BL Lac object 1ES 1218+304 located at a redshift of z=0.182. A gamma-ray signal was detected with a statistical significance of 10.4 standard deviations (10.4 sigma) for the observations taken during the first three months of 2007, confirming the discovery of this object made by the MAGIC collaboration. The photon spectrum between ~160 GeV and ~1.8 TeV is well described by a power law with an index of Gamma = 3.08 +/- 0.34_stat +/- 0.2_sys. The integral flux is Phi(E > 200 GeV) = (12.2 +/- 2.6) X 10^-12 cm^-2 s^-1, which corresponds to ~6% of that of the Crab Nebula. The light curve does not show any evidence for VHE flux variability. Using lower limits on the density of the extragalactic background light in the near to mid-infrared we are able to limit the range of intrinsic energy spectra for 1ES 1218+304. We show that the intrinsic photon spectrum has an index that is harder than Gamm...

  7. Differential Effects of Low-Phenylalanine Protein Sources on Brain Neurotransmitters and Behavior in C57Bl/6-Pahenu2 Mice

    OpenAIRE

    2014-01-01

    Phenylketonuria (PKU) is an inborn error of metabolism caused by a deficiency of the enzyme phenylalanine hydroxylase, which metabolizes phenylalanine (phe) to tyrosine. A low-phe diet plus amino acid (AA) formula is necessary to prevent cognitive impairment; glycomacropeptide (GMP) contains minimal phe and provides a palatable alternative to the AA formula. Our objective was to assess neurotransmitter concentrations in brain and the behavioral phenotype of PKU mice (Pahenu2 on the C57Bl/6 ba...

  8. Engraftment of bone marrow-derived cells after nonlethal radiation in syngeneic C57BL/6mice%Engraftment of bone marrow-derived cells after nonlethal radiation in syngeneic C57BL/6 mice

    Institute of Scientific and Technical Information of China (English)

    Wu Liao; Tan Li; Wang Yu; Liu Dengqun; Shi Chunmeng

    2015-01-01

    Objective To study the characteristics of cell engraftment in mice at a lower dose under nonlethal radiated condition.Methods A syngeneic C57BL/6 mouse model,transplanted with 1 × 107 bone marrow cells and exposed to 2.5 Gy whole body irradiation (WBI),was selected to study the chimerism of cells from green fluorescent protein positive (GFP +) transgenic mice.The control group was injected with GFP + cells without receiving irradiation.In addition,an allogenic transplantation model of BALB/c mice was also investigated which was infused by GFP + cells from C57BL/6 mice.The engraftment of bone marrow-derived cells (BMDCs) was detected by immunohistochemistry in bone marrow,liver,lung,small intestine and spleen.Results The transplanted bone marrow cells successfully grafted in the haematopoietic tissues from syngeneic GFP transgenic mice.The transplanted GFP+ cells were also detected in the non-haematopoietic tissues,such as the small intestine,liver,spleen and lung,after irradiation.However,a lethal dose irradiation of 8 Gy was required to establish successful chimerism in allogeneic transplantation model by infusing the bone marrow cells from C57BL/6 mice to BALB/c mice.Conclusions Bone marrow-derived cells can be successfully grafted into various recipient tissues receiving a 2.5 Gy dose of radiation in syngeneic mice,but not in allogeneic mice.This nonlethal model may help to further study the plasticity and mechanism of bone marrow-derived cells in tissue repair and regeneration after radiation injury.

  9. The B-L Phase Transition: Implications for Cosmology and Neutrinos

    CERN Document Server

    Schmitz, Kai

    2013-01-01

    We investigate the possibility that the hot thermal phase of the early universe is ignited in consequence of the B-L phase transition, which represents the cosmological realization of the spontaneous breaking of the Abelian gauge symmetry associated with B-L, the difference between baryon number B and lepton number L. Prior to the B-L phase transition, the universe experiences a stage of hybrid inflation. Towards the end of inflation, the false vacuum of unbroken B-L decays, which entails tachyonic preheating as well as the production of cosmic strings. The dynamics of the B-L breaking Higgs field and the B-L gauge degrees of freedom, in combination with thermal processes, generate an abundance of heavy (s)neutrinos. These (s)neutrinos decay into radiation, thereby reheating the universe, generating the baryon asymmetry of the universe and setting the stage for the thermal production of gravitinos. We study the B-L phase transition in the full supersymmetric Abelian Higgs model, for which we derive and discus...

  10. Electroweak vacuum stability in classically conformal $B-L$ extension of the Standard Model

    CERN Document Server

    Das, Arindam; Papapietro, Nathan

    2015-01-01

    We consider the minimal U(1)$_{B-L}$ extension of the Standard Model (SM) with the classically conformal invariance, where an anomaly free U(1)$_{B-L}$ gauge symmetry is introduced along with three generations of right-handed neutrinos and a U(1)$_{B-L}$ Higgs field. Because of the classically conformal symmetry, all dimensional parameters are forbidden. The $B-L$ gauge symmetry is radiatively broken through the Coleman-Weinberg mechanism, generating the mass for the $U(1)_{B-L}$ gauge boson ($Z^\\prime$ boson) and the right-handed neutrinos. Through a small negative coupling between the SM Higgs doublet and the $B-L$ Higgs field, the negative mass term for the SM Higgs doublet is generated and the electroweak symmetry is broken. In this model context, we investigate the electroweak vacuum instability problem in the SM. It is known that in the classically conformal U(1)$_{B-L}$ extension of the SM, the electroweak vacuum remains unstable in the renormalization group analysis at the one-loop level. In this pape...

  11. [Study on identification of Gastrodia elata Bl. by Fourier self-deconvolution infrared spectroscopy].

    Science.gov (United States)

    Cheng, Ze-Feng; Xu, Rui; Cheng, Cun-Gui

    2007-09-01

    In the present article the FTIR spectra of the wild and planting Gastrodia elata Bl. from different habitats and its confusable varieties such as Canna edulis Ker-Gawl, Colocasia esculenta (L.) Schott and Solanum tuberosum L. were obtained by horizontal attenuated total reflection infrared spectroscopy (HATR-FTIR), and were all transformed by Fourier self-deconvolution. The authors investigated the discrepancy extent of Fourier self-deconvolution of Gastrodia elata Bl and confusable varieties under various bandwidth and enhancement, and found that the discrepancy extent of Gastrodia elata Bl and confusable varieties was the most obvious when the bandwidth was between 75.0 and 76.0 and enhancement was 3.2. By adopting Fourier self-deconvolution infrared spectroscopy (FSD-IR) analytical method the samples were studied in detail. The results showed that we could find out the difference among them by means of Fourier self-deconvolution infrared spectroscopy, although it was very difficult to find out the difference in FSD-IR spectra of wild and planting Gastrodia elata Bl., and asexual reproduction and sexual reproduction Gastrodia elata Bl. The difference in FSD-IR spectra between Gastrodia elata Bl. and its confusable varieties is also very great. Therefore, this method can be used to recognize different Gastrodia elata Bl. and its confusable varieties simply, rapidly and accurately.

  12. DEVELOPMENTAL TOXICITY OF METHANOL: PATHOGENESIS IN CD-1 AND C57BL/6J MICE EXPOSED IN WHOLE EMBRYO CULTURE

    Science.gov (United States)

    BACKGROUND: Methanol causes axial skeleton and craniofacial defects in both CD-1 and C57BL/6J mice during gastrulation, but C57BL/6J embryos are more severely affected. We evaluated methanol-induced pathogenesis in CD-1 and C57BL/6J embryos exposed during gastrulation in whole em...

  13. X-Ray Spectral Variability of Extreme BL Lac AGN H1426+428

    CERN Document Server

    Falcone, A D; Finley, J P

    2004-01-01

    Between 7 March 2002 and 15 June 2002, intensive X-ray observations were carried out on the extreme BL Lac object H1426+428 with instruments on board the Rossi X-ray Timing Explorer (RXTE). These instruments provide measurements of H1426+428 in the crucial energy range that characterizes the first peak of its spectral energy distribution. This peak, which is almost certainly due to synchrotron emission, has previously been inferred to be in excess of 100 keV. By taking frequent observations over a four-month campaign, which included $\\sim$450 ksec of RXTE time, studies of flux and spectral variability on multiple timescales were performed, along with studies of spectral hysteresis. The 3-24 keV X-ray flux and spectra exhibited significant variability, implying variability in the location of the first peak of the spectral energy distribution. Hysteresis patterns were observed, and their characteristics have been discussed within the context of emission models.

  14. Multiwavelength Intraday Variability of the BL Lac S5 0716+714

    CERN Document Server

    Gupta, Alok C; Wiita, P J; Rani, B; Sokolovsky, K V; Mohan, P; Mangalam, A; Marchili, N; Fuhrmann, L; Agudo, I; Bach, U; Bachev, R; Böttcher, M; Gabanyi, K E; Gaur, H; Hawkins, K; Kimeridze, G N; Kurtanidze, O M; Kurtanidze, S O; Lee, C -U; Liu, X; McBreen, B; Nesci, R; Nestoras, G; Nikolashvili, M G; Ohlert, J M; Palma, N; Peneva, S; Pursimo, T; Semkov, E; Strigachev, A; Webb, J R; Wiesemeyer, H; Zensus, J A

    2012-01-01

    We report results from a 1 week multi-wavelength campaign to monitor the BL Lac object S5 0716+714 (on December 9-16, 2009). In the radio bands the source shows rapid (~ (0.5-1.5) day) intra-day variability with peak amplitudes of up to ~ 10 %. The variability at 2.8 cm leads by about 1 day the variability at 6 cm and 11 cm. This time lag and more rapid variations suggests an intrinsic contribution to the source's intraday variability at 2.8 cm, while at 6 cm and 11 cm interstellar scintillation (ISS) seems to predominate. Large and quasi-sinusoidal variations of ~ 0.8 mag were detected in the V, R and I-bands. The X-ray data (0.2-10 keV) do not reveal significant variability on a 4 day time scale, favoring reprocessed inverse-Compton over synchrotron radiation in this band. The characteristic variability time scales in radio and optical bands are similar. A quasi-periodic variation (QPO) of 0.9 - 1.1 days in the optical data may be present, but if so it is marginal and limited to 2.2 cycles. Cross-correlatio...

  15. Effect of High-Fat Diet on Peripheral Neuropathy in C57BL/6 Mice

    Directory of Open Access Journals (Sweden)

    Lingling Xu

    2014-01-01

    Full Text Available Objective. Dyslipidemia may contribute to the development of peripheral neuropathy, even in prediabetics; however, few studies have evaluated vascular dysfunction and oxidative stress in patients with peripheral neuropathy. Methods. Using high-fat diet- (HFD- induced prediabetic C57BL/6 mice, we assessed motor and sensory nerve conduction velocity (NCV using a BIOPAC System and thermal algesia with a Plantar Test (Hargreaves’ method Analgesia Meter. Intraepidermal nerve fiber density and mean dendrite length were tested following standard protocols. Vascular endothelial growth factor-A (VEGF-A and 12/15-lipoxygenase (12/15-LOX were evaluated by immunohistochemistry and Western blot, respectively. Results. HFD-fed mice showed deficits in motor and sensory NCV, thermal hyperalgesia, reduced mean dendrite length, and VEGF-A expression in the plantar skin and increased 12/15-LOX in the sciatic nerve (P<0.05 compared with controls. Conclusion. HFD may cause large myelinated nerve and small sensory nerve fiber damage, thus leading to neuropathy. The mean dendrite length may be a more sensitive marker for early detection of peripheral neuropathy. Reduced blood supply to the nerves and increased oxidative stress may contribute to the development and severity of peripheral neuropathy.

  16. Effect of high-fat diet on peripheral neuropathy in C57BL/6 mice.

    Science.gov (United States)

    Xu, Lingling; Tang, Dou; Guan, Meiping; Xie, Cuihua; Xue, Yaoming

    2014-01-01

    Objective. Dyslipidemia may contribute to the development of peripheral neuropathy, even in prediabetics; however, few studies have evaluated vascular dysfunction and oxidative stress in patients with peripheral neuropathy. Methods. Using high-fat diet- (HFD-) induced prediabetic C57BL/6 mice, we assessed motor and sensory nerve conduction velocity (NCV) using a BIOPAC System and thermal algesia with a Plantar Test (Hargreaves' method) Analgesia Meter. Intraepidermal nerve fiber density and mean dendrite length were tested following standard protocols. Vascular endothelial growth factor-A (VEGF-A) and 12/15-lipoxygenase (12/15-LOX) were evaluated by immunohistochemistry and Western blot, respectively. Results. HFD-fed mice showed deficits in motor and sensory NCV, thermal hyperalgesia, reduced mean dendrite length, and VEGF-A expression in the plantar skin and increased 12/15-LOX in the sciatic nerve (P < 0.05 compared with controls). Conclusion. HFD may cause large myelinated nerve and small sensory nerve fiber damage, thus leading to neuropathy. The mean dendrite length may be a more sensitive marker for early detection of peripheral neuropathy. Reduced blood supply to the nerves and increased oxidative stress may contribute to the development and severity of peripheral neuropathy.

  17. The pc-scale structure and evolution of BL Lac PKS 0003-066

    CERN Document Server

    Horiuchi, S; West, C J; Tzioumis, A K; Phillips, C J; Lovell, J E J; Reynolds, J E; Ellingsen, S P; Reid, P B; Cimo, G; Quick, J F H; Koyama, Y; Briggs, F H; Brisken, W F

    2006-01-01

    We present the results of global VLBI observations of the BL Lac object PKS 0003-066 at 2.3 and 8.6 GHz, over a 10 year period using data from new and archived VLBA, geodetic VLBI, and global VLBI (including the use of new disk-based recording and software correlation systems) observations. Inter-continental baselines resolve this source into a compact core and three jet components that move away from the core with proper motions ranging between \\~0.1 mas/yr for the outer jet component and ~1.4 mas/yr for the fastest inner jet component, i.e. apparent speeds of ~2.0 c to ~21.6 c respectively. This result is in contrast to previous studies of this source which did not reveal significant jet motions from limited data sets. We find that the fast inner jet components catch up to the more slowly moving outer jet components and interact strongly, causing local brightening of the jet in the interaction. We document the body of VLBI data for this source, as well as other supporting radio observations, as a basis for ...

  18. Discovery of VHE gamma-rays from the distant BL Lac 1ES 0347-121

    CERN Document Server

    Aharonian, F; Barres de Almeida, U; Bazer-Bachi, A R; Behera, B; Beilicke, M; Benbow, W; Bernlöhr, K; Boisson, C; Bolz, O; Borrel, V; Braun, I; Brion, E; Brown, A M; Buhler, R; Bulik, T; Büsching, I; Boutelier, T; Carrigan, S; Chadwick, P M; Chounet, L M; Clapson, A C; Coignet, G; Cornils, R; Costamante, L; Dalton, M; Degrange, B; Dickinson, H J; Djannati-Ata:, A; Domainko, W; O'Connor-Drury, L; Dubois, F; Dubus, G; Dyks, J; Egberts, K; Emmanoulopoulos, D; Espigat, P; Farnier, C; Feinstein, F; Fiasson, A; Förster, A; Fontaine, G; Funk, Seb; Fuling, M; Gallant, Y A; Giebels, B; Glicenstein, J F; Glück, B; Goret, P; Hadjichristidis, C; Hauser, D; Hauser, M; Heinzelmann, G; Henri, G; Hermann, G; Hinton, J A; Hoffmann, A; Hofmann, W; Holleran, M; Hoppe, S; Horns, D; Jacholkowska, A; De Jager, O C; Jung, I; Katarzynski, K; Kendziorra, E; Kerschhaggl, M; Khelifi, B; Keogh, D; Komin, Nu; Kosack, K; Lamanna, G; Latham, I J; Lemiere, A; Lemoine-Goumard, M; Lenain, J P; Lohse, T; Martin, J M; Martineau-Huynh, O; Marcowith, A; Masterson, C; Maurin, D; Maurin, G; McComb, T J L; Moderski, R; Moulin, E; De Naurois, Mathieu; Nedbal, D; Nolan, S J; Ohm, S; Olive, J P; De Ona Wilhelmi, E; Orford, K J; Osborne, J L; Ostrowski, M; Panter, M; Pedaletti, G; Pelletier, G; Petrucci, P O; Pita, S; Pühlhofer, G; Punch, M; Ranchon, S; Raubenheimer, B C; Raue, M; Rayner, S M; Renaud, M; Ripken, J; Rob, L; Rolland, L; Rosier-Lees, S; Rowell, G; Rudak, B; Ruppel, J; Sahakian, V V; Santangelo, A; Schlickeiser, R; Schock, F; Schroder, R; Schwanke, U; Schwarzburg, S; Schwemmer, S; Shalchi, A; Sol, H; Spangler, D; Stawarz,; Steenkamp, R; Stegmann, C; Superina, G; Tam, P H; Tavernet, J P; Terrier, R; Van Eldik, C; Vasileiadis, G; Venter, C; Vialle, J P; Vincent, P; Vivier, M; Völk, H J; Volpe, F; Wagner, S J; Ward, M; Zdziarski, A A; Zech, A

    2007-01-01

    Aims: Our aim is to study the production mechanism for very-high-energy (VHE; >100GeV) gamma-rays in distant active galactic nuclei (AGN) and use the observed VHE spectrum to derive limits on the Extragalactic Background Light (EBL). We also want to determine physical quantities through the modeling of the object's broad-band spectral energy distribution (SED). Methods: VHE observations (~25h live time) of the BL Lac 1ES 0347-121 (redshift z=0.188) were conducted with the High Energy Stereoscopic System (H.E.S.S.) between August and December 2006. Contemporaneous X-ray and UV/optical observations from the SWIFT satellite are used to interpret the SED of the source in terms of a synchrotron self Compton (SSC) model. Results: An excess of 327 events, corresponding to a statistical significance of 10.1 standard deviations, is detected from 1ES 0347-121. Its photon spectrum, ranging from ~250GeV to ~3TeV, is well described by a power law with a photon index of Gamma = 3.10 +/- 0.23_stat +/- 0.10_sys. The integral...

  19. Probiotics lower plasma glucose in the high-fat fed C57BL/6J mouse.

    Science.gov (United States)

    Andersson, U; Bränning, C; Ahrné, S; Molin, G; Alenfall, J; Onning, G; Nyman, M; Holm, C

    2010-06-01

    Today, the gut microbiota is considered a key organ in host nutritional metabolism and recent data have suggested that alterations in gut microbiota contribute to the development of type 2 diabetes and obesity. Accordingly, a whole range of beneficial effects relating to inflammation and gut health have been observed following administration of probiotics to both humans and different animal models. The objective of this study was to evaluate the metabolic effects of an oral probiotic supplement, Lactobacillus plantarum DSM 15313, to high-fat diet (HFD) fed C57BL/6J mice, a model of human obesity and early diabetes. The mice were fed the experimental diets for 20 weeks, after which the HFD had induced an insulin-resistant state in both groups compared to the start of the study. The increase in body weight during the HFD feeding was higher in the probiotic group than in the control group, however, there were no significant differences in body fat content. Fasting plasma glucose levels were lower in the group fed the probiotic supplement, whereas insulin and lipids were not different. Caecal levels of short-chain fatty acids were not significantly different between the groups. An oral glucose tolerance test showed that the group fed probiotics had a significantly lower insulin release compared to the control group, although the rate of glucose clearance was not different. Taken together, these data indicate that L. plantarum DSM 15313 has anti-diabetic properties when fed together with an HFD.

  20. Neural stem cell isolation and culture from C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    S Koirala

    2015-07-01

    Full Text Available INTRODUCTION A widely used in vitro culture, the neurosphere assay (NSA has provided a means to retrospectively identify neural progenitor cells as well as to determine both their selfrenewal capacity. Objective of study was to isolate and compare growth of the embryonic neuronal stem cell and adult neuronal stem cells in presence of Epidermal Growth Factor (EGF and Fibroblastic Growth Factor (FGF2. MATERIALS AND METHODS Embryonic neuronal stem cell were collected from cortical plate of dorsal telencephalon of fifteen C57BL/6 transgenic mice using stereoscopic microscope on 11th gestational day (GD. Adult mammalian neuronal stem cells taken from subventricular zone (SVZ of the lateral ventricles and subgranular layer of the dentate gyrus of the hippocampus were cultured. The growth for the neurosphere was then observed in interval of 24 and 72 hours. RESULT The adult stem cell culture showed few intact cells with high amount of debris and 9% heterogeneous sphere after 24 hours while only 20 % was observed at the end of 72 hours. Higher proliferation rate was observed in embryonic neurospheres than the adult stem cell culture. CONCLUSION Presence of EGF and basic FGF2 is essential for culture of neurospheres.DOI: http://dx.doi.org/10.3126/jcmsn.v10i2.12946 Journal of College of Medical Sciences-Nepal, 2014, Vol.10(2; 1-3

  1. Erionite induces production of autoantibodies and IL-17 in C57BL/6 mice

    Energy Technology Data Exchange (ETDEWEB)

    Zebedeo, Christian Nash; Davis, Chad [Department of Biological Sciences, Idaho State University, Pocatello, ID (United States); Peña, Cecelia [Northwest Nazarene University, Nampa, ID (United States); Ng, Kok Wei [Department of Biological Sciences, Idaho State University, Pocatello, ID (United States); Pfau, Jean C., E-mail: pfaujean@isu.edu [Department of Biological Sciences, Idaho State University, Pocatello, ID (United States)

    2014-03-15

    Background: Erionite has similar chemical and physical properties to amphibole asbestos, which induces autoantibodies in mice. Current exposures are occurring in North Dakota due to the use of erionite-contaminated gravel. While erionite is known to cause mesothelioma and other diseases associated with asbestos, there is little known about its effects on the immune system. Objectives: We performed this study to determine whether erionite evokes autoimmune reactions in mice. Methods: Bone marrow derived macrophages (BMDM) were used to measure toxicity induced by erionite. Cytokine production by BMDM and splenocytes of C57BL/6 mice was examined by bead arrays and ELISA following exposure to erionite, amphiboles and chrysotile. Wild type C57BL/6 mice were exposed to saline, erionite, amphibole asbestos (Libby 6-Mix) or chrysotile through intratracheal instillations at equal mass (60 μg/mouse). Seven months after exposure, sera were examined for anti-nuclear antibodies (ANA) and IL-17. Immunohistochemistry was used to detect immune complex deposition in the kidneys. Results: Erionite and tremolite caused increased cytokine production belonging to the T{sub H}17 profile including IL-17, IL-6, TGF-β, and TNF-α. The frequency of ANA was increased in mice treated with erionite or amphibole compared to saline-treated mice. IL-17 and TNF-α were elevated in the sera of mice treated with erionite. The frequency of immune complex deposition in the kidneys increased from 33% in saline-treated mice to 90% with erionite. Conclusions: These data demonstrate that both erionite and amphibole asbestos induce autoimmune responses in mice, suggesting a potential for adverse effects in exposed communities. - Highlights: • Erionite, a fibrous mineral, is a current public health concern in the western USA. • Erionite exposure induces antinuclear autoantibodies in exposed mice. • Erionite induces a clear Th17 cytokine response in vitro and in vivo. • These responses were

  2. The BL-Lac gamma-ray blazar PKS 1424+240 associated with a group of galaxies at z=0.6010

    CERN Document Server

    Rovero, A C; Donzelli, C; Pichel, A

    2016-01-01

    PKS 1424+240 is a BL-Lac blazar with unknown redshift that was detected at high-energy gamma rays by Fermi-LAT with a hard spectrum. At VHE, it was first detected by VERITAS and later confirmed by MAGIC. Its spectral energy distribution is highly attenuated at VHE gamma rays, which is coherent with distant sources. Several estimations enabled the redshift to be constrained to the range 0.6 < z < 1.3. These results place PKS 1424+240 in the very interesting condition of being probably the most distant blazar that has been detected at VHE. The ambiguity in the redshift is still large enough to prevent precise studies of the EBL and the intrinsic blazar spectrum. Given the difficulty of measuring spectroscopic redshifts for BL-Lac objects directly, we aim to establish a reliable redshift value for this blazar by finding its host group of galaxies. Elliptical galaxies are associated with groups, and BL-Lac objects are typically hosted by them, so we decided to search for the host group of the blazar. For th...

  3. Differential Mammary Gland Development in FVB and C57Bl/6 Mice: Implications for Breast Cancer Research

    Directory of Open Access Journals (Sweden)

    Breanne M. Anderson

    2011-10-01

    Full Text Available A growing body of research suggests a linkage between pubertal mammary gland development and environmental factors such as diet as modifiers of long term breast cancer risk. Much of this research is dependent upon mouse models, which may vary between studies. However, effects may be strain dependent and further modified by diet, which has not been previously examined. Therefore, the objective of the present study was to determine whether mammary gland development differs between FVB and C57Bl/6 strains on diets containing either n-6 or n-3 polyunsaturated fats. Developmental measures related to onset of puberty and mammary gland development differed between strains. Mice fed the n-3 polyunsaturated fatty acids (PUFA diet were shown to have lower numbers of terminal end buds, a marker of mammary gland development. This study helps to further clarify differences in development and dietary response between FVB and C57Bl/6 mice in order to more appropriately relate mammary gland research to human populations.

  4. A Statistical Study of XBLs, RBLs and FSRQs at 1.5 GHz

    Institute of Scientific and Technical Information of China (English)

    2007-01-01

    BL Lac objects are similar to the flat spectrum radio quasars in many aspects except regarding the emission lines. In order to study their relationship, we selected 56 BL Lacertae objects (33 X-ray-selected, 23 radio-selected) and 45 flat spectrum radio quasars, analyzed their radio luminosities and core-dominance parameters. We found that the radio luminosities of the radio selected BL Lac objects located in between the X-ray selected BL Lac objects and the flat spectrum radio quasars. However, this intermediate position does not hold for the core-dominance parameter: the RBLs have the largest core-dominance parameters. This suggests that the core-dominance parameter can not be taken as a sequencing criterion. We also investigated the correlation between the luminosity and the core-dominance parameter for the three subclasses. We concluded that, here, the sequence XBL-RBL-FSRQ still exists.

  5. PATHOGENESIS OF METHANOL-INDUCED CRANIOFACIAL DEFECTS IN C57BL/6J MICE

    Science.gov (United States)

    BACKGROUND: Methanol administered to C57BL/6J mice during gastrulation causes severe craniofacial dysmorphology. We describe dysmorphogenesis, cell death, cell cycle assessment, and effects on development of cranial ganglia and nerves observed following administration of methanol...

  6. Blóðhlutanotkun á íslenskum gjörgæsludeildum

    OpenAIRE

    Karl Erlingur Oddason 1983

    2013-01-01

    Inngangur: Blóðhlutagjafir eru mikilvægur hluti gjörgæslumeðferðar, en vegna aukaverkana er vaxandi áhersla lögð á aðhaldssemi við gjöf blóðhluta. Áherslur á aðhaldsemi endurspeglast í nýlegum klínískum leiðbeiningum á Landspítala. Ekki eru fyrir hendi upplýsingar um umfang blóðhlutagjafa á gjörgæsludeildum Landspítala og hversu vel leiðbeiningum er fylgt. Tilgangur rannsóknarinnar er að kanna notkun blóðhluta á gjörgæsludeildum Landspítala og fylgni við klínískar leiðbeiningar. Efniviður...

  7. Non-minimal B-L inflation with observable gravity waves

    Energy Technology Data Exchange (ETDEWEB)

    Okada, Nobuchika, E-mail: okadan@ua.edu [Department of Physics and Astronomy, University of Alabama, Tuscaloosa, AL 35487 (United States); Rehman, Mansoor Ur, E-mail: rehman@udel.edu [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States); Shafi, Qaisar, E-mail: shafi@bartol.udel.edu [Bartol Research Institute, Department of Physics and Astronomy, University of Delaware, Newark, DE 19716 (United States)

    2011-07-27

    We consider non-minimal {lambda}{phi}{sup 4} inflation in a gauged non-supersymmetric U(1){sub B-L} model containing the gravitational coupling {xi}R{Phi}{sup +}{Phi}, where R denotes the Ricci scalar and the standard model singlet inflaton field {Phi} spontaneously breaks the U(1){sub B-L} symmetry. Including radiative corrections, the predictions 0.956{<=}n{sub s}{<=}0.984 and 0.007{<=}r{<=}0.1 for the scalar spectral index and tensor to scalar ratio r lie within the current WMAP 1-{sigma} bounds. If the B-L symmetry breaking scale is of order a TeV or so, one of the three right handed neutrinos is a plausible cold dark matter candidate. Bounds on the dimensionless parameters {lambda}, {xi} and the gauge coupling g{sub B-L} are obtained.

  8. A discussion of $Bl$ conservation on a two dimensional magnetic field plane in watt balances

    CERN Document Server

    Li, Shisong; Huang, Songling

    2015-01-01

    The watt balance is an experiment being pursued in national metrology institutes for precision determination of the Planck constant $h$. In watt balances, the $1/r$ magnetic field, expected to generate a geometrical factor $Bl$ independent to any coil horizontal displacement, can be created by a strict two dimensional, symmetric (horizontal $r$ and vertical $z$) construction of the magnet system. In this paper, we present an analytical understanding of magnetic field distribution when the $r$ symmetry of the magnet is broken and the establishment of the $Bl$ conservation is shown. By using either Gauss's law on magnetism with monopoles or conformal transformations, we extend the $Bl$ conservation to arbitrary two dimensional magnetic planes where the vertical magnetic field component equals zero. The generalized $Bl$ conservation allows a relaxed physical alignment criteria for watt balance magnet systems.

  9. C57BL/6J小鼠初级听皮层神经元凋亡与caspase-3表达的年龄相关性改变%The Age-related Changes of the Expression of Caspase-3 and the apoptosis States of Neurons in Primary Auditory Cortex(AI) of C57BL/6J Mice

    Institute of Scientific and Technical Information of China (English)

    李洪波; 陈继川; 姬长友

    2009-01-01

    目的 探讨不同月龄C57BL/6J小鼠初级听皮层中caspase-3的表达及初级听皮层神经元凋亡情况,探讨两者之间的关系以及caspase-3、凋亡在老年性聋发生、发展中的作用.方法 分别选取2月龄(1 5~20克)和10月龄(45~60克)C57BL/6J小鼠各15只,免疫组织化学法染色检测两组C57BL/6J小鼠初级听皮层caspase-3的表达情况,末端转移酶介导的原位缺口末端标记染色(TUNEL)技术检测两组小鼠仞级听皮层神经元凋亡状况.结果 与2月龄组C57BL/6J小鼠相比,10月龄组C57BL/6J小鼠初级听皮层中caspase-3的表达显著增多,初级听皮层神经元凋亡数目明显增多(P值均<0.01),且caspase-3的表达与神经元的凋亡呈正相关(r=0.5202).结论 caspase-3的表达可能在老年性聋的发生、发展过程中起重要作用,它参与了小鼠初级听皮层神经元的凋亡调控过程,可能是老年性聋的发病机制中一个重要因素.%Objective This study is to study the age related changes of the expression of caspase-3 and the apoptosis states of neurons in primary auditory cortex of 15 young C57BL/6J mice(2 months, 15~20 g) and 15 old C57BL/6J mice(10 months, 50~60 g) and to determine probable physical effects underlying these changes. This paper also discusses the relationship of caspase-3 and apotosis states in primary auditory cortex, the possible role of caspase-3 in primary auditory cortex and the pathogenesis of presbycusis. Methods The immunohistochemical methods were applied to explore the differences of the expression of caspase-3 and the apoptosis states determined by TUNEI. method in the primary auditory cortex between young and old C57BL/6J mice. Results The expression of caspase-3 and apoptosis in Al of old C57BL/6J mice was significantly higher than that in the counterpart of young C57BL/6J mice. Conclusion The results presented a direct morphological evidence for the strengthening of caspase-3 in the primary auditory cortex in

  10. ON (∈, ∈∨q)-FUZZY FILTERS OF BL-ALGEBRAS

    Institute of Scientific and Technical Information of China (English)

    Xueling MA; Jianming ZHAN

    2008-01-01

    The authors introduce the notions of (∈, ∈∨q)-fuzzy Boolean (implicative, positive implica-tive, and fantastic) filters in BL-algebras, present some characterizations on these generalized fuzzy filters, and describe the relations among these generalized fuzzy filters. It is proved that an (∈, ∈∨q)-fuzzy filter in a BL-algebra is Boolean (implicative) if and only if it is both positive implicative and fantastic.

  11. [Prooxidant and cytotoxic action of N-acetylcysteine and glutathione combined with vitamin Bl2b].

    Science.gov (United States)

    Solov'eva, M E; Solov'ev, V V; Faskhutdinova, A A; Kudriavtsev, A A; Akatov, V S

    2007-01-01

    We studied the prooxidant and cytotoxic action of thiols N-acetylcystein (NAC) and glutathione (GSH) combined with vitamin Bl2b. The synergism of action of the thiols and Bl2b resulted in human carcinoma cell damage was found. It was shown that GSH and NAC in physiological doses combined with Bl2b caused the initiation of apoptosis. It was established that prooxidant action of the thiols combined with vitamin Bl2b, i. e. generation and accumulation of hydrogen peroxide in culture medium, led to intracellular oxidative stress and injury of cell redox system. These effects were completely abolished by nonthiol antioxidants catalase and pyruvate. The chelators of iron phenanthroline and deferoxamine did not suppress the H2O2 accumulation in culture medium but significantly inhibited the cell death induced by the thiols combined with Bl2b. Therefore, the thiols GSH and NAC widely used as antioxidants, in combination with vitamin Bl2b show prooxidant characteristics and induce, with the participation of intracellular iron, apoptotic HEp-2 cell death.

  12. Sound objects – Auditory objects – Musical objects

    DEFF Research Database (Denmark)

    Hjortkjær, Jens

    2015-01-01

    The auditory system transforms patterns of sound energy into perceptual objects but the precise definition of an ‘auditory object’ is much debated. In the context of music listening, Pierre Schaeffer argued that ‘sound objects’ are the fundamental perceptual units in ‘musical objects......’. In this paper, I review recent neurocognitive research suggesting that the auditory system is sensitive to structural information about real-world objects. Instead of focusing solely on perceptual sound features as determinants of auditory objects, I propose that real-world object properties are inherent...

  13. Sound objects – Auditory objects – Musical objects

    DEFF Research Database (Denmark)

    Hjortkjær, Jens

    2016-01-01

    The auditory system transforms patterns of sound energy into perceptual objects but the precise definition of an ‘auditory object’ is much debated. In the context of music listening, Pierre Schaeffer argued that ‘sound objects’ are the fundamental perceptual units in ‘musical objects......’. In this paper, I review recent neurocognitive research suggesting that the auditory system is sensitive to structural information about real-world objects. Instead of focusing solely on perceptual sound features as determinants of auditory objects, I propose that real-world object properties are inherent...

  14. Learning Vector Quantization for Classifying Astronomical Objects

    Institute of Scientific and Technical Information of China (English)

    2003-01-01

    The sizes of astronomical surveys in different wavebands are increas-ing rapidly. Therefore, automatic classification of objects is becoming ever moreimportant. We explore the performance of learning vector quantization (LVQ) inclassifying multi-wavelength data. Our analysis concentrates on separating activesources from non-active ones. Different classes of X-ray emitters populate distinctregions of a multidimensional parameter space. In order to explore the distributionof various objects in a multidimensional parameter space, we positionally cross-correlate the data of quasars, BL Lacs, active galaxies, stars and normal galaxiesin the optical, X-ray and infrared bands. We then apply LVQ to classify them withthe obtained data. Our results show that LVQ is an effective method for separatingAGNs from stars and normal galaxies with multi-wavelength data.

  15. Clinical Chemistry Reference Intervals for C57BL/6J, C57BL/6N, and C3HeB/FeJ Mice (Mus musculus).

    Science.gov (United States)

    Otto, Gordon P; Rathkolb, Birgit; Oestereicher, Manuela A; Lengger, Christoph J; Moerth, Corinna; Micklich, Kateryna; Fuchs, Helmut; Gailus-Durner, Valérie; Wolf, Eckhard; Hrabě de Angelis, Martin

    2016-01-01

    Although various mouse inbred strains are widely used to investigate disease mechanisms and to establish new therapeutic strategies, sex-specific reference intervals for laboratory diagnostic analytes that are generated from large numbers of animals have been unavailable. In this retrospective study, we screened data from more than 12,000 mice phenotyped in the German Mouse Clinic from January 2006 through June 2014 and selected animals with the genetic background of C57BL/6J, C57BL/6N, or C3HeB/FeJ. In addition, we distinguished between the C57BL/6NTac substrain and C57BL/6N mice received from other vendors. The corresponding data sets of electrolytes (sodium, potassium, calcium, chloride, inorganic phosphate), lipids (cholesterol, triglyceride), and enzyme activities (ALT, AST, ALP, α-amylase) and urea, albumin, and total protein levels were analyzed. Significant effects of age and sex on these analytes were identified, and strain- or substrain- and sex-specific reference intervals for 90- to 135-d-old mice were calculated. In addition, we include an overview of the literature that reports clinical chemistry values for wild-type mice of different strains. Our results support researchers interpreting clinical chemistry values from various mouse mutants and corresponding wild-type controls based on the examined strains and substrains.

  16. The B-L phase transition. Implications for cosmology and neutrinos

    Energy Technology Data Exchange (ETDEWEB)

    Schmitz, Kai

    2012-07-15

    We investigate the possibility that the hot thermal phase of the early universe is ignited in consequence of the B-L phase transition, which represents the cosmological realization of the spontaneous breaking of the Abelian gauge symmetry associated with B-L, the difference between baryon number B and lepton number L. Prior to the B-L phase transition, the universe experiences a stage of hybrid inflation. Towards the end of inflation, the false vacuum of unbroken B-L symmetry decays, which entails tachyonic preheating as well as the production of cosmic strings. Observational constraints on this scenario require the B-L phase transition to take place at the scale of grand unification. The dynamics of the B-L breaking Higgs field and the B-L gauge degrees of freedom, in combination with thermal processes, generate an abundance of heavy (s)neutrinos. These (s)neutrinos decay into radiation, thereby reheating the universe, generating the baryon asymmetry of the universe and setting the stage for the thermal production of gravitinos. The B-L phase transition along with the (s)neutrino-driven reheating process hence represents an intriguing and testable mechanism to generate the initial conditions of the hot early universe. We study the B-L phase transition in the full supersymmetric Abelian Higgs model, for which we derive and discuss the Lagrangian in arbitrary and unitary gauge. As for the subsequent reheating process, we formulate the complete set of Boltzmann equations, the solutions of which enable us to give a detailed and time-resolved description of the evolution of all particle abundances during reheating. Assuming the gravitino to be the lightest superparticle (LSP), the requirement of consistency between hybrid inflation, leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses, in particular a lower bound on the gravitino mass of 10GeV. As an alternative to gravitino dark matter, we consider the case of

  17. Quasi-objects, Cult Objects and Fashion Objects

    DEFF Research Database (Denmark)

    Andersen, Bjørn Schiermer

    2011-01-01

    This article attempts to rehabilitate the concept of fetishism and to contribute to the debate on the social role of objects as well as to fashion theory. Extrapolating from Michel Serres’ theory of the quasi-objects, I distinguish two phenomenologies possessing almost opposite characteristics....... These two phenomenologies are, so I argue, essential to quasi-object theory, yet largely ignored by Serres’ sociological interpreters. They correspond with the two different theories of fetishism found in Marx and Durkheim, respectively. In the second half of the article, I introduce the fashion object...... as a unique opportunity for studying the interchange between these two forms of fetishism and their respective phenomenologies. Finally, returning to Serres, I briefly consider the theoretical consequences of introducing the fashion object as a quasi-object....

  18. WHAT IS THE REDSHIFT OF THE GAMMA-RAY BL LAC SOURCE S4 0954+65?

    Energy Technology Data Exchange (ETDEWEB)

    Landoni, M. [INAF—Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Brera, Via E. Bianchi 46, I-23807 Merate (Italy); Falomo, R. [INAF—Istituto Nazionale di Astrofisica, Osservatorio Astronomico di Padova, Vicolo dell’Osservatorio 5, I-35122 Padova (Italy); Treves, A. [Universita’ degli Studi dell’Insubria, Via Valleggio 11, I-22100 (Italy); Scarpa, R.; Payá, D. Reverte, E-mail: marco.landoni@brera.inaf.it [Instituto de Astrofsica de Canarias, C/O Via Lactea, s/n E38205—La Laguna (Tenerife) (Spain)

    2015-12-15

    High signal-to-noise ratio spectroscopic observations of the BL Lac object S4 0954+65 at the alleged redshift z = 0.367 are presented. This source was detected at gamma frequencies by the MAGIC (TeV) and FERMI (GeV) telescopes during a remarkable outburst that occurred in 2015 February, making the determination of its distance particularly relevant for our understanding of the properties of the extragalactic background light. Contrary to previous reports on the redshift, we found that the optical spectrum is featureless at an equivalent width limit of ∼0.1 Å. A critical analysis of the existing observations indicates that the redshift is still unknown. Based on the new data we estimate a lower limit to the redshift at z ≥ 0.45.

  19. Dietary magnesium deficiency affects gut microbiota and anxiety-like behaviour in C57BL/6N mice

    DEFF Research Database (Denmark)

    Pyndt Jørgensen, Bettina; Winther, Gudrun; Kihl, Pernille;

    2015-01-01

    and whether there was a link between the two. A total of 20 C57BL/6 mice, fed either a standard diet or a magnesium-deficient diet for 6 weeks, were tested using the light-dark box anxiety test. Gut microbiota composition was analysed by denaturation gradient gel electrophoresis. RESULTS: We demonstrated......OBJECTIVE: Magnesium deficiency has been associated with anxiety in humans, and rodent studies have demonstrated the gut microbiota to impact behaviour. METHODS: We investigated the impact of 6 weeks of dietary magnesium deficiency on gut microbiota composition and anxiety-like behaviour...... that the gut microbiota composition correlated significantly with the behaviour of dietary unchallenged mice. A magnesium-deficient diet altered the gut microbiota, and was associated with altered anxiety-like behaviour, measured by decreased latency to enter the light box. CONCLUSION: Magnesium deficiency...

  20. X-Ray Luminosity and Spectral Variability in the TEV BL Lac 1ES2344+514

    CERN Document Server

    Giommi, P; Perlman, E S

    1998-01-01

    The results of a series of five \\sax observations of the TeV BL Lac object 1ES2344+514 are briefly presented. Large amplitude luminosity variability, associated to impressive spectral changes in the hard X-rays, have been found. The shape of the lightcurve depends on energy, with the flare starting and ending in the hard band, but with maximum intensity possibly reached earlier in the soft X-rays. The luminosity and spectral changes may be due to a shift of the peak of the synchrotron emission from the soft X-rays to the hard X-ray band similar to that detected during \\sax observations of MKN 501.

  1. Development of high spatial resolution X-ray CT system at BL47XU in SPring-8

    CERN Document Server

    Uesugi, K; Yagi, N; Tsuchiyama, A; Nakano, T

    2001-01-01

    High spatial resolution, micrometer range, X-ray CT system has been developed at SPring-8. The experiments were performed at the undulator beam line BL47XU. An 'in-vacuum type' undulator is employed as an X-ray source, and the X-rays are monochromatized with a liquid nitrogen cooled Si(1 1 1) double crystal monochromator. High precision rotation stage with air bearing was used for sample rotation. The transmitted images were obtained with a two-dimensional image detector, which consists of a single crystal phosphor screen (Lu sub 2 SiO sub 5 : Ce), an objective lens and a cooled CCD camera. In this system the smallest effective pixel size was set to 0.5 mu mx0.5 mu m. As a result of the experiments, three-dimensional images of a few micrometer-order texture has been successfully obtained with the developed CT system.

  2. C57BL/6J及NIH Swiss小鼠在抑郁模型中的行为学表现%Behavioral manifestations in animal models with depression between C57BL/6J and NIH Swiss mice

    Institute of Scientific and Technical Information of China (English)

    李亮萍; 王倩; 潘彦伶; 张怡慧; 魏佳优; 陈翌华; 高天明

    2012-01-01

    Objective To investigate behavioral differences in models with depression between C57BL/6J and NIH Swiss mice with different genetic backgrounds,to provide references for selection of examination animals in anti- depression drug researches,and to provide the useful animal models for invcstigating the effects of genetic factors on occurrence of depression.Methods Behavioral manifestations of depression in C57BI/6J and NIH Swiss mice (n=14 each) were detected under stress conditions using forced swimming test and tail suspension test.Open field test was used to detect the spontaneous motility of two kinds of mice.Results The immobility time of C57BL/6J mice was significantly longer than that of NIH Swiss mice [ (133.198 ± 5.749) s vs (80.265± 10.939) s,P=0.000] in forced swimming test,which was contrast to that in tail suspension test [ (151.315±12.161)s vs (95.107±14.649)s,P=0.007].Howevcr in open field test,no diffcrcncc was found in total distance,standing number,movement time,total distance in fringe area,movement time in fringe area,total distance in central area and movement time in central area between the two kinds of mice.Conclusion C57BL/6J mice are easier to show the depressive-like behavior under stress conditions,while NIH Swiss mice show a certain of depression resistance.These different behavioral manifestations in two different kinds of mice may be caused by genetic factors.%目的 探讨两种不同遗传背景的小鼠C57BL/6J及NIH Swiss在抑郁模型中的行为学差异,为抗抑郁药物研究的实验动物选择提供参考,为研究遗传学因素在抑郁症发病过程中的作用提供有用的动物模型.方法 C57BL/6J、NIH Swiss小鼠各14只,利用强迫游泳实验和悬尾实验检测两种小鼠在应激条件下的抑郁样行为表现;利用旷场实验检测两种小鼠的自主运动能力.结果 强迫游泳实验中,C57BL/6J小鼠的不动时间明显长于NIH Swiss小鼠[(133.198±5.749)s比(80.265±10.939)s,P=0

  3. Ⅰ型单纯疱疹病毒UL12基因在大肠杆菌BL21和Rosetta菌中的差异表达%The differential expression of HSV -1 UL12 gene in E.coil BL21 and E.coli Rosetta

    Institute of Scientific and Technical Information of China (English)

    陈恬; 李学东; 代富英; 张磊; 赖升凤; 余小平; 曹康

    2012-01-01

    目的 构建Ⅰ型单纯疱疹病毒(HSV -1)的UL12基因原核重组表达质粒pET32a - ULI2,比较重组表达质粒pET32a -UL12在E.coli BL21和E.coli Rosetta表达产量与生物学活性.方法 使用PCR的方法扩增出HSV -1的UL12基因,克隆至原核表达质粒pET32a(+),构建出重组质粒pET32a - UL12,分别转化E.coli BL21和E coli Rosetta菌.经SDS - PAGE鉴定分析目的蛋白的表达差异,并比较在两种菌中目的蛋白的活性.结果 重组质粒pET32a - UL12在E.coli BL21和E.coli Rosetta的包涵体中均表达出了碱性核酸酶融合蛋白,E.coli Rosetta中表达的碱性核酸酶融合蛋白表达量较大,而E.coliBL21中表达的碱性核酸酶活性更高.结论 成功构建了表达出了具有较高活性的HSV -1碱性核酸酶融合蛋白,为进一步研究抗HSV -1药物奠定了基础.%OBJECTIVE To construct the recombinant plasmid of pET32a - UL12 and to compare the expression level and biological activity of expression products of pET32a - UL12 in E. coli BL21 and E. coli Rosetta. METHODS The UL12 gene of HSV -1 was obtained by PCR,and was cloned into pET32a( + ). The recombinant plasmid of pET32a -UL12 was transformed into E. coli BL21 and E. coli Rosetta. The expressed proteins of the E. coli BL21 and E. coli Rosetta were identified by SDS - PAGE. Then, the expression level and the biological activity of the two proteins were compared in this study. RESULTS The UL12 gene was successfully expressed both in E. coli BL21 and in E. coli Rosetta. The UL12 gene expressed more proteins in E. coli Rosetta than that in E. coli BL21, while the biological activity of the proteins expressed in E. coli BL21 was higher than that in E. coli Rosetta. CONCLUSION The HSV - 1 alkaline nuclease with high biological activity was obtained in the study which is very important in the research of anti - virus remedies.

  4. High fat/high cholesterol diet induced lipid accumulation in pulmonary tissues of C57BL/6J mice%高脂高胆固醇饮食致C57BL/6J小鼠肺组织脂质蓄积的研究

    Institute of Scientific and Technical Information of China (English)

    王双; 朱婷婷; 方严; 陈婷; 张恋; 练雪梅

    2012-01-01

    目的:研究高脂高胆固醇饮食(Paigen 饮食)是否可以导致C57BL/6J小鼠肺组织的脂质蓄积.方法:66只C57BL/6J雄性6~8周龄小鼠随机分为2组,分别喂饲普通饮食和Paigen饮食,于喂养12、16、20周3个时间点,取主动脉做冰冻切片,油红O染色观察粥样硬化斑块形成情况;肺组织冰冻切片油红O染色,观察肺组织脂质蓄积情况;体外培养A549细胞观察用不同浓度低密度脂蛋白(Low density lipoprotein,LDL)处理后,A549细胞内脂质蓄积情况.结果:Paigen饮食可导致C57BL/6J小鼠主动脉粥样硬化;同时,不同时间点C57BL/6J小鼠肺组织油红O染色结果提示该饮食还可以导致C57BL/6J小鼠肺组织出现脂质蓄积,并随着时间延长而加剧;不同浓度LDL刺激A549细胞的油红O染色结果提示:A549细胞的脂质蓄积与LDL处理的浓度间存在剂最效应关系.结论:Paigen 饮食可以导致C57BL/6J小鼠肺脏出现时间依赖性的脂质蓄积,其机制可能与肺泡Ⅱ型上皮细胞的脂质代谢异常有关.%Objective: To investigate whether high fat/high cholesterol diet(Paigen diet) could lead lipid accumulation in pulmonary tissues of C57BL/6J mice. Methods: Sixty six C57BL/6J male mice were randomly divided into two groups and were treated with regular diet and high fat/high cholesterol diet respectively. The pulmonary tissues were collected at the 12lh,16th week and the 20th week alter feeding respectively. The aortas atherosclerotic plaque and lipidosis in pulmonary tissues were determined by oil red 0 staining. A549 cells were cultured in vitro and were treated with different concentrations of low density lipoprotein(LDL) to observe the effect of cholesterol loading on alveolar lipid accumulation in vitro. Results: Aorta atherosclerosis plaques were observed in high fat/high cholesterol diet treated C57BI76J mice. Oil red 0 staining of pulmonary tissues at different time points suggested that high fat/ high cholesterol diet

  5. Photohadronic origin of $\\gamma$-ray BL Lac emission: implications for IceCube neutrinos

    CERN Document Server

    Petropoulou, Maria; Padovani, Paolo; Mastichiadis, Apostolos; Resconi, Elisa

    2015-01-01

    The recent IceCube discovery of 0.1-1 PeV neutrinos of astrophysical origin opens up a new era for high-energy astrophysics. Although there are various astrophysical candidate sources, a firm association of the detected neutrinos with one (or more) of them is still lacking. A recent analysis of plausible astrophysical counterparts within the error circles of IceCube events showed that likely counterparts for nine of the IceCube neutrinos include mostly BL Lacs, among which Mrk 421. Motivated by this result and a previous independent analysis on the neutrino emission from Mrk 421, we test the BL Lac-neutrino connection in the context of a specific theoretical model for BL Lac emission. We model the spectral energy distribution (SED) of the BL Lacs selected as counterparts of the IceCube neutrinos using a one-zone leptohadronic model and mostly nearly simultaneous data. The neutrino flux for each BL Lac is self-consistently calculated, using photon and proton distributions specifically derived for every individ...

  6. U(1)B-L symmetry restoration and effective neutrino species

    Science.gov (United States)

    Ishida, Hiroyuki; Takahashi, Fuminobu

    2014-06-01

    The U(1)B-L symmetry could be restored during inflation, since the BICEP2 results suggest a GUT-scale inflation with the Hubble parameter, Hinf≃1014 GeV, close to the U(1)B-L breaking scale. We consider a scenario in which the B-L Higgs field dominates the Universe after inflation, and mainly decays into the U(1)B-L gauge bosons, whose subsequent decays reheat the Universe. Interestingly, if one of the right-handed neutrinos is extremely light and behaves as dark radiation or hot dark matter, its abundance is determined by the B-L charge assignment and the relativistic degree of freedom in plasma. We find that ΔNeff takes discrete values between 0.188 and 0.220 in the standard model plus three right-handed neutrinos, depending on whether the decay into heavier right-handed neutrinos is kinematically accessible or not. In the fiveness U(1)5 case, we find that ΔNeff takes discrete values between 0.313 and 0.423. The tension between BICEP2 and Planck can be partially relaxed by dark radiation.

  7. U(1)$_{B-L}$ Symmetry Restoration and Effective Neutrino Species

    CERN Document Server

    Ishida, Hiroyuki

    2014-01-01

    The U(1)$_{B-L}$ symmetry could be restored during inflation, since the BICEP2 results suggest a GUT-scale inflation with the Hubble parameter, $H_{\\rm inf} \\simeq 10^{14}$ GeV, close to the U(1)$_{B-L}$ breaking scale. If the ${B-L}$ Higgs field dominates the Universe after inflation, it can mainly decay into the U(1)$_{B-L}$ gauge bosons, whose subsequent decays reheat the Universe. Interestingly, if one (or more) of the right-handed neutrinos is extremely light and behaves as dark radiation or hot dark matter, its abundance is determined solely by the $B-L$ charge assignment and the relativistic degree of freedom in plasma. We find that $\\Delta N_{\\rm eff}$ takes discrete values between $0.188$ and $0.220$ in the standard model plus three right-handed neutrinos, depending on whether the decay into heavier right-handed neutrinos are kinematically accessible or not. In the fiveness U(1)$_{\\bf 5}$ case, we find that $\\Delta N_{\\rm eff}$ takes discrete values between $0.274$ and $0.386$. The tension between BI...

  8. Dyadic social interaction of C57BL/6 mice versus interaction with a toy mouse: conditioned place preference/aversion, substrain differences, and no development of a hierarchy.

    Science.gov (United States)

    Pinheiro, Barbara S; Seidl, Simon S; Habazettl, Eva; Gruber, Bernadette E; Bregolin, Tanja; Zernig, Gerald

    2016-04-01

    Impaired social interaction is a hallmark symptom of many psychiatric diseases, including dependence syndromes (substance use disorders). Helping the addict reorient her/his behavior away from the drug of abuse toward social interaction would be of considerable therapeutic benefit. To study the neural basis of such a reorientation, we have developed several animal models in which the attractiveness of a dyadic (i.e. one-to-one) social interaction (DSI) can be compared directly with that of cocaine as a prototypical drug of abuse. Our models are based on the conditioned place preference (CPP) paradigm. In an ongoing effort to validate our experimental paradigms in C57BL/6 mice to make use of the plethora of transgenic models available in this genus, we found the following: (a) DSI with a live mouse produced CPP, whereas an interaction with an inanimate mouse-like object (i.e. a 'toy mouse'; toy mouse interaction) led to conditioned place aversion - but only in the Jackson substrain (C57BL/6J). (b) In the NIH substrain (C57BL/6N), both DSI and toy mouse interaction produced individual aversion in more than 50% of the tested mice. (c) Four 15 min DSI episodes did not result in the development of an observable hierarchy, that is, dominance/subordination behavior in the overwhelming majority (i.e. 30 of 32) of the tested Jackson mouse pairs. Therefore, dominance/subordination does not seem to be a confounding variable in our paradigm, at least not in C57BL/6J mice. Respective data for NIH mice were too limited to allow any conclusion. The present findings indicate that (a) DSI with a live mouse produces CPP to a greater degree than an interaction with an inanimate object resembling a mouse and that (b) certain substrain differences with respect to CPP/aversion to DSI do exist between the Jax and NIH substrain of C57BL/6 mice. These differences have to be considered when choosing a proper mouse substrain model for investigating the neural basis of DSI reward versus

  9. Histopathological assessment of C57Bl/J mice organs exposed to tannery effluents

    Directory of Open Access Journals (Sweden)

    Joyce Moreira de Souza

    2016-03-01

    Full Text Available The effluent produced in tanneries can cause environmental damage and public health problems when disposed of improperly. However, few toxicological studies have evaluated the effects of the intake of tannery wastewater by mammals. The objective of this study is the histological assessment of organs of C57Bl/J mice exposed to the intake of different concentrations of raw tannery effluents, beginning with the hypothesis that these effluents can cause damage to the histological structure of the organs. The animals were divided into the following groups: control (0% effluent and exposed to 0.1%, 1%, and 5% raw tannery effluent diluted in water, for a period of 120 days. For the histopathological evaluations, samples of the liver, kidney, spleen, heart, and lung were collected, fixed, and stained by the hematoxylin and eosin staining techniques. No anomalies were observed in kidney, spleen, heart, and lung fragments. Alterations were observed only in liver fragments. Moderate hydropic degeneration was detected in animals exposed to tannery effluents, mainly in the periportal space. A large number of necrotic hepatocytes (p<0.05 were detected, especially in animals exposed to higher tannery effluent concentrations. Further, the largest number of hepatocytes with karyomegaly (p<0.05 was observed in animals exposed to the highest effluent concentrations. Our study suggests that the observed alterations are related to the intake of tannery effluents and that these effluents cause changes that lead to an increase of free radical production and direct aggressions to hepatocyte membranes as well as to the appearance of hepatocellular karyomegaly.

  10. Test Research on Drawing Property of BL1 Wire Rod%BL1盘条拉拔性能试验研究

    Institute of Scientific and Technical Information of China (English)

    刘泽亚; 周应其; 欧光清

    2004-01-01

    BL1盘条进行拉拔性能试验研究,通过结果对比,摸索出BL1盘条的最佳化学成分、力学性能,优化出钢丝最佳生产工艺参数.粗、中拉平均部分压缩率为23%,拉拔速度为2.4 m/s,细拉平均部分压缩率为14%,拉拔速度为3.5 m/s,保持良好的润滑和冷却,可将φ6.5 mm高线盘条拉拔到φ0.70mm以下,总压缩率超过99%.

  11. A new B-L model without right-handed neutrinos

    CERN Document Server

    Patra, Sudhanwa; Yaguna, Carlos E

    2016-01-01

    We propose and study a novel extension of the Standard Model based on the B-L gauge symmetry that can account for dark matter and neutrino masses. In this model, right-handed neutrinos are absent and the gauge anomalies are canceled instead by four chiral fermions with fractional B-L charges. After the breaking of $U(1)_{B-L}$, these fermions arrange themselves into two Dirac particles, the lightest of which is automatically stable and plays the role of the dark matter. We determine the regions of the parameter space consistent with the observed dark matter density and show that they can be partially probed via direct and indirect dark matter detection or collider searches at the LHC. Neutrino masses, on the other hand, can be explained by a variant of the type-II seesaw mechanism involving one of the two scalar fields responsible for the dark matter mass.

  12. Spontaneous B-L Breaking as the Origin of the Hot Early Universe

    CERN Document Server

    Buchmüller, Wilfried; Schmitz, Kai

    2012-01-01

    The decay of a false vacuum of unbroken B-L symmetry is an intriguing and testable mechanism to generate the initial conditions of the hot early universe. If B-L is broken at the grand unification scale, the false vacuum phase yields hybrid inflation, ending in tachyonic preheating. The dynamics of the B-L breaking Higgs field and thermal processes produce an abundance of heavy neutrinos whose decays generate entropy, baryon asymmetry and gravitino dark matter. We study the phase transition for the full supersymmetric Abelian Higgs model. For the subsequent reheating process we give a detailed time-resolved description of all particle abundances. The competition of cosmic expansion and entropy production leads to an intermediate period of constant 'reheating' temperature, during which baryon asymmetry and dark matter are produced. Consistency of hybrid inflation, leptogenesis and gravitino dark matter implies relations between neutrino parameters and superparticle masses, in particular a lower bound on the gr...

  13. Postnatal Hematopoiesis and Gut Microbiota in NOD Mice Deviate from C57BL/6 Mice

    Directory of Open Access Journals (Sweden)

    Dina Silke Malling Damlund

    2016-01-01

    Full Text Available Neonatal studies in different mouse strains reveal that early life colonization affects the development of adaptive immunity in mice. The nonobese diabetic (NOD mouse spontaneously develops autoimmune diabetes, but neonatal studies of NOD mice are lacking. We hypothesized that NOD mice deviate from another much used mouse strain, C57BL/6, with respect to postnatal microbiota and/or hematopoiesis and compared this in newborn mice of dams housed under the same conditions. A distinct bacteria profile rich in staphylococci was found at postnatal days (PND 1–4 in NOD mice. Furthermore, a distinct splenic cell profile high in a granulocytic phenotype was evident in the neonatal NOD mice whereas neonatal C57BL/6 mice showed a profile rich in monocytes. Neonatal expression of Reg3g and Muc2 in the gut was deviating in NOD mice and coincided with fewer bacteria attaching to the Mucosal surface in NOD compared to C57BL/6 mice.

  14. Blødningsforstyrrelser hos kvinder. Undersøgelse og behandling i almen praksis

    DEFF Research Database (Denmark)

    Astrup, Karen

    1994-01-01

    Artiklen omfatter resultaterne af en spørgeskemaundersøgelse til 200 praktiserende læger efteråret 1992 om lægernes undersøgelse og behandling af forskellige former for blødningsforstyrrelser hos kvinder i almen praksis. Undersøgelsen blev udført mhp. Karen Astrup's deltagelse i expertpanelet til...... konsensuskonferencen "Blødningsforstyrrelser hos kvinder" febr. 1993. Udgivelsesdato: 1994......Artiklen omfatter resultaterne af en spørgeskemaundersøgelse til 200 praktiserende læger efteråret 1992 om lægernes undersøgelse og behandling af forskellige former for blødningsforstyrrelser hos kvinder i almen praksis. Undersøgelsen blev udført mhp. Karen Astrup's deltagelse i expertpanelet til...

  15. Synchrotron total reflection X-ray fluorescence at BL-16 microfocus beamline of Indus-2

    Science.gov (United States)

    Tiwari, M. K.; Singh, A. K.; Das, Gangadhar; Chowdhury, Anupam; Lodha, G. S.

    2014-04-01

    Determination of ultra trace elements is important in many disciplines both in basic and applied sciences. Numerous applications show their importance in medical science, environmental science, materials science, food processing and semiconductor industries and in maintaining the quality control of ultra pure chemicals and reagents. We report commissioning of a synchrotron based total reflection x-ray fluorescence (TXRF) facility on the BL-16 microfocus beamline of Indus-2. This paper describes the performance of the BL-16 TXRF spectrometer and the detailed description of its capabilities through examples of measured results.

  16. Secondary Metabolites Analysis of Methanol Extract of Surian (Toona sureni (Bl. Merr Leaf as Antioxidant Potential.

    Directory of Open Access Journals (Sweden)

    Yuhernita

    2011-04-01

    Full Text Available Secondary Metabolites Analysis of Methanol Extract of Surian (Toona sureni (Bl. Merr Leaf as AntioxidantPotential. The study of performed secondary metabolites from the methanol extract of Surian (Toona sureni (Bl. Merrleaves have been done by thin-layer chromatography (TLC method. The result showed that methanol extract of Surianleaves consist of alkaloid, flavonoid, polyphenol and terpenoid. All of them positively have the ability to scavenge 2,2-diphenyl-1-picrylhydrazyl (DPPH. It has IC50 (4.80 are smaller than the ascorbat acid standard (IC50 = 9.23.

  17. Selecting a Reference Object

    Science.gov (United States)

    Miller, Jared E.; Carlson, Laura A.; Hill, Patrick L.

    2011-01-01

    One way to describe the location of an object is to relate it to another object. Often there are many nearby objects, each of which could serve as a candidate to be the reference object. A common theoretical assumption is that features that make a given object salient relative to the candidate set are instrumental in determining which is selected.…

  18. Effects of bixin in high-fat diet-fed-induced fatty liver in C57BL/6J mice

    Institute of Scientific and Technical Information of China (English)

    Rosa Martha Perez Gutierrez; Rita Valadez Romero

    2016-01-01

    Objective: To evaluate the anti-obesity activity of bixin (BIX) on C57BL/6J mice which were fed a high-fat diet (HFD) and to determine the mechanism of this effect. Methods: C57BL/6J mice were separately fed a high-calorie diet or a normal diet for 8 weeks, then they were treated with BIX for another 13 weeks. After administration for 13 weeks, the animals were sacrificed. Body adiposity, serum lipid level, and insulin resistance were evaluated. In addition, a histological assay of pancreas and liver, an evaluation of the inhibitory properties on pancreatic lipase, and a-amylase were conducted. Results: Administration of BIX significantly decreased the body weight gain, adipocyte size, fat pad weights, hepatic lipid levels in HFD-induced obese mice. In addition, reduced liver weight exhibited decreased serum leptin levels, malic enzyme, glucose-6-phosphate dehydrogenase, hepatic fatty acid synthase, aspartate aminotransferase, alanine aminotransferase and hepatic phosphatidate phosphohydrolase activity. However, superoxide dismutase, catalase, glutathione peroxidase, and glutathione levels were increased in hepatic tissue. BIX also decreased lipid and carbohydrates absorption due to inhibition of pancreatic lipase and a-amylase. Long term supplementation of BIX significantly decreased hyperlipidemia, insulin resistance and glucose level. Decreased levels of hepatic steatosis and the islets of Langerhans appeared less shrunken in HFD-fed mice. Conclusions: The antiobesity effect of BIX appears to be associated at least in part, to its inhibitory effect on lipids and carbohydrate digestion enzymes such as pancreatic lipase, a-glucosidase, and a-amylase. The results suggested that BIX also act as an antioxidant and may treat visceral obesity normalizing glucose levels, improving insulin resistance and increasing energy expenditure. Therefore, achiote which has a main component, the carotenoid BIX, could be a viable food for the treatment of obesity and diabetes.

  19. Caveolin-1敲除对C57BL/6小鼠繁殖性能及 子代离乳前体质量的影响%Effect of Caveolin-1 knockout on weight and reproductive performance before weaning in C57BL/6 mice

    Institute of Scientific and Technical Information of China (English)

    俞悦; 易健; 蔡光先; 刘柏炎

    2011-01-01

    目的 探讨小窝蛋白Caveolin-1敲除对C57BL/6小鼠离乳前繁殖性能及体质量的影响.方法 分别对Caveolin-1基因敲除小鼠和同源C57小鼠进行体质量、初产日龄、胎次间隔时间、平均产仔数及离乳存活率的观察及分析.结果 C57BL/6小鼠鼠仔平均体质量均高于Caveolin-1基因敲除鼠,在1、7、14 d时两者比较差异无统计学意义(P>0.05);21 d时,两者差异具有统计学意义(P<0.05);两组初产日龄、胎次间隔时间及平均产仔数差异无统计学意义(P>0.05),但C57BL/6小鼠离乳存活率明显高于基因敲除鼠,两者差异具有统计学意义(P<0.05).结论 Caveolin-1敲除小鼠的体质量下降、繁殖性能下降.%Objective evaluate the effects of Caveolin-1 knockout on weight and reproductive performance before weaning in C57BI76 mice. Methods The growth curves, primiparous age, parity time interval, the average litter sizes and weaning survival were observed and analyzed respectively in caveolin-1 knockout mice and C57 mice homologous. Results The average body weight of C57BL/6 newborn mice were higher than that of Caveolin-1 knockout mice in 1st, 7th and 14th days, but there were no significant differences (P>0.05); in 21st day, the difference was significant (P<0.05); the primiparous age, parity, litter size and the average interval between the two was no significant difference (P>0.05), but the survival rate of C57BL/6 mice was significantly higher than that of knockout mice(P<0.05). Conclusion Caveolin-1 knockout can slow the growth and decrease the reproductive ability of C57BL/6 mice.

  20. Specification of Concurrent Objects

    DEFF Research Database (Denmark)

    Sørensen, Morten U.

    Concurrent objects are named concurrent processes that interact by invoking each other's operations. We describe how such concurrent objects can be specified, how objects can be composed, and how it can be shown that one object refines another.First a model is defined, based on a transition...... relation over two objects and an event. In the model, objects can be composed by parallel composition, encapsulation, and hiding of operations. Refinement between objects is defined as fair trace inclusion.A specification language is presented where objects can be specified operationally by abstract...

  1. Mating Behavior of the Common Lizard Lacerta vivipara and the Relationship with Environment Factors%模拟生境中胎生蜥蜴的交配行为及其与环境因子的关系

    Institute of Scientific and Technical Information of China (English)

    李殿伟; 刘鹏; 赵文阁

    2011-01-01

    摘要:2007年和2008年的5月,采用瞬时扫描取样法和全事件观察法,对模拟生境中胎生蜥蝎(Lacerta vivipara)的交配行为进行了详细的研究。结果表明,胎生蜥蜴交配行为的基本模式为:①追逐;②咬腹;③环抱;④交媾;⑤分离。其中各交配行为持续时间占总交配时间的百分比分别为:追逐占2. 35%,咬腹占0.51%,环抱占8.44%,交媾占88.70%。交配活动主要发生在8:00时以后,其中9:00 ~ 13:00时比较集中,此间光照强度平均为(1 009.90±77.06) ×102 lx[(307.00×102)~(1 999.00×102)1x],气温平均为(31.53 ±0.36)℃(25. 10 ~39. 20℃),地表温度平均为(41.03±0.60)℃(28.30 ~56.30℃),湿度平均为27.54%±0.58%(20. 00% ~ 43. 50%)。经检验,交配活动受地表温度(r=0. 829,P<0.01)、光照强度(r =0.664,P<0. 05)与气温(r=0.606,P<0.05)的影响显著。%The mating behaviors of Lacerta viviparavteie studied in the May of 2007 and 2008 by the methods of instantaneous and scan sampling and of all-occurrence recording. The results show that the basic patterns of mating behavior of L vivipara are chasing; biting abdomen; encircling; sexual intercourse and separating. Chasing accounts for 2.35% of total time; biting abdomen for 0.51% ; encircling for 8.44% and sexual intercourse for 88. 70% . The mating activities begin at 8 a. M. And focus from 9 a. M. To 1 p. M. During the period, the average illumination intensity is ( 1 009. 90 ±77. 06) x 102 lx [ (307. 00 x 102 ) - (1 999. 00 x 102)lx]; the average air temperature is (31.53 ±0.36)% (25.10 - 39.2CC ) ; the average ground temperature is (41.03 ±0.60)1] (28.30 -56.30%); and the average humidity is 27.54% ±0.58% (20. 00% - 43. 50% ). Environment factors, such as ground temperature, illumination and air temperature, mainly affected the mating behaviors of L. Vivipara.

  2. The Minimal SUSY $B-L$ Model: From the Unification Scale to the LHC

    CERN Document Server

    Ovrut, Burt A; Spinner, Sogee

    2015-01-01

    This paper introduces a random statistical scan over the high-energy initial parameter space of the minimal SUSY $B-L$ model--denoted as the $B-L$ MSSM. Each initial set of points is renormalization group evolved to the electroweak scale--being subjected, sequentially, to the requirement of radiative $B-L$ and electroweak symmetry breaking, the present experimental lower bounds on the $B-L$ vector boson and sparticle masses, as well as the lightest neutral Higgs mass of $\\sim$125 GeV. The subspace of initial parameters that satisfies all such constraints is presented, shown to be robust and to contain a wide range of different configurations of soft supersymmetry breaking masses. The low-energy predictions of each such "valid" point - such as the sparticle mass spectrum and, in particular, the LSP - are computed and then statistically analyzed over the full subspace of valid points. Finally, the amount of fine-tuning required is quantified and compared to the MSSM computed using an identical random scan. The ...

  3. Galactic Gamma Ray Excess and Dark Matter Phenomenology in a $U(1)_{B-L}$ Model

    CERN Document Server

    Biswas, Anirban; Khan, Sarif

    2016-01-01

    In this work, we have considered a gauged $U(1)_{\\rm B-L}$ extension of the Standard Model (SM) with three right handed neutrinos for anomaly cancellation and two additional SM singlet complex scalars with non-trivial B-L charges. One of these is used to spontaneously break the $U(1)_{\\rm B-L}$ gauge symmetry, leading to Majorana masses for the neutrinos through the standard Type I seesaw mechanism, while the other becomes the dark matter (DM) candidate in the model. We test the viability of the model to simultaneously explain the DM relic density observed in the CMB data as well as the Galactic Centre (GC) $\\gamma$-ray excess seen by Fermi-LAT. We show that for DM masses in the range 40-55 GeV and for a wide range of $U(1)_{\\rm B-L}$ gauge boson masses, one can satisfy both these constraints if the additional neutral Higgs scalar has a mass around the resonance region. In studying the dark matter phenomenology and GC excess, we have taken into account theoretical as well as experimental constraints coming fr...

  4. The effect of altered gut flora on glucose intolerance in C57BL/6NTac mice

    DEFF Research Database (Denmark)

    Rune, Ida; Nielsen, Dennis Sandris; Hansen, Axel Jacob Kornerup;

    Background Recent studies have shown that long term broad spectrum antibiotic treatment improves glucose tolerance in mice. We hypothesize that it is primarily the early life altering of the gut microbiota, which will have an impact on glucose intolerance. Study setup 40 C57BL/6NTac mice were ran...

  5. Spectroscopy of the Largest Ever γ-Ray-selected BL Lac Sample

    Science.gov (United States)

    Shaw, Michael S.; Romani, Roger W.; Cotter, Garret; Healey, Stephen E.; Michelson, Peter F.; Readhead, Anthony C. S.; Richards, Joseph L.; Max-Moerbeck, Walter; King, Oliver G.; Potter, William J.

    2013-02-01

    We report on spectroscopic observations covering most of the 475 BL Lacs in the second Fermi Large Area Telescope (LAT) catalog of active galactic nuclei (AGNs). Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic \\tilde{z} from 0.23 to 0.33 and include redshifts as large as z = 2.471. Spectroscopic redshift minima from intervening absorbers have \\tilde{z}= 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M • ~ 108.5 - 109, substantially larger than the mean of optical AGNs and LAT Flat Spectrum Radio Quasar samples. A slow increase in M • with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the γ-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance.

  6. Radiative Symmetry Breaking in the Supersymmetric Minimal B-L Extended Standard Model

    CERN Document Server

    Burell, Zachary

    2016-01-01

    The Standard Model (SM) of particle physics is a precise model of electroweak interactions, however there is growing tension between the SM and observations (neutrino oscillations, dark matter, dark energy, baryogenesis, among others). There is no reason to expect the validity of the ad hoc SM to remain intact at energy scales above a few TeV, thus a more fundamental theory will almost certainly be required. Motivated by these considerations, we investigate a Supersymmetric version of a natural extension of the SM, the $U(1)_{B-L}$ model, that is obtained by gauging the accidental B-L symmetry that exists in the ordinary SM. The Supersymmetric $U(1)_{B-L}$ extended SM can resolve the neutrino mass problem, the dark matter problem, the hierarchy problem, and provides a mechanism for establishing the observed baryon asymmetry of the Universe. When we include quantum corrections to the Higgs potential of the model, we find that Radiative $B-L$ symmetry breaking occurs through the interplay between large Majorana...

  7. A spontaneous mutation characterized by chronic proliferative dermatitis in C57BL mice

    NARCIS (Netherlands)

    HogenEsch, H.; Gijbels, M.J.J.; Offerman, E.; Hooft, J. van; Bekkum, D.W. van; Zurcher, C.

    1993-01-01

    Chronic proliferative dermatitis is a new spontaneous mutation in C57BL/Ka mice. Breeding results suggest an autosomal recessive mode of inheritance. Mutant mice develop skin lesions at the age of 5 to 6 weeks. The lesions occur in the ventral and dorsal skin of the body, whereas ears, footpads, and

  8. SSC Model Fits to Simultaneous Fermi and CAO observations of Bl Lac's

    Science.gov (United States)

    Gordon, Tyler; Macomb, Daryl J.; Hand, Jared; Norris, Jay P.; Long, Min

    2016-01-01

    The Challis Astronomical Observatory (CAO) has been surveying a sample of blazar-type AGN since 2010. The CAO blazar sample includes4 3 sources - comprising 30 FSRQs, 15 BL Lacs, one radio galaxy and four unclassified sources - covering a redshift range 0.02 Potter and Cotter (MNRAS, 2012, 423, 756-765).

  9. SPECTROSCOPY OF THE LARGEST EVER {gamma}-RAY-SELECTED BL LAC SAMPLE

    Energy Technology Data Exchange (ETDEWEB)

    Shaw, Michael S.; Romani, Roger W.; Healey, Stephen E.; Michelson, Peter F. [Department of Physics/KIPAC, Stanford University, Stanford, CA 94305 (United States); Cotter, Garret; Potter, William J. [Department of Astrophysics, University of Oxford, Oxford OX1 3RH (United Kingdom); Readhead, Anthony C. S.; Richards, Joseph L.; Max-Moerbeck, Walter; King, Oliver G. [Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)

    2013-02-20

    We report on spectroscopic observations covering most of the 475 BL Lacs in the second Fermi Large Area Telescope (LAT) catalog of active galactic nuclei (AGNs). Including archival measurements (correcting several erroneous literature values) we now have spectroscopic redshifts for 44% of the BL Lacs. We establish firm lower redshift limits via intervening absorption systems and statistical lower limits via searches for host galaxies for an additional 51% of the sample leaving only 5% of the BL Lacs unconstrained. The new redshifts raise the median spectroscopic z-tilde from 0.23 to 0.33 and include redshifts as large as z = 2.471. Spectroscopic redshift minima from intervening absorbers have z-tilde = 0.70, showing a substantial fraction at large z and arguing against strong negative evolution. We find that detected BL Lac hosts are bright ellipticals with black hole masses M {sub .} {approx} 10{sup 8.5} - 10{sup 9}, substantially larger than the mean of optical AGNs and LAT Flat Spectrum Radio Quasar samples. A slow increase in M {sub .} with z may be due to selection bias. We find that the power-law dominance of the optical spectrum extends to extreme values, but this does not strongly correlate with the {gamma}-ray properties, suggesting that strong beaming is the primary cause of the range in continuum dominance.

  10. Right-handed neutrino dark matter under the B-L gauge interaction

    CERN Document Server

    Kaneta, Kunio; Lee, Hye-Sung

    2016-01-01

    We study the right-handed neutrino (RHN) dark matter candidate in the minimal U(1)_{B-L} gauge extension of the standard model. The U(1)_{B-L} gauge symmetry offers three RHNs which can address the origin of the neutrino mass, the relic dark matter, and the matter-antimatter asymmetry of the universe. The lightest among the three can be a sufficiently long-lived dark matter candidate, without an additional stability mechanism, which is under the B-L gauge interaction. We investigate various scenarios for this dark matter candidate with the correct relic density by means of the freeze-out or freeze-in mechanism. A viable RHN dark matter mass lies in a wide range including keV to TeV scale. We emphasize the sub-electroweak scale light B-L gauge boson case, and identify the parameter region motivated from the dark matter physics, which can be tested with the planned experiments including the CERN SHiP experiment.

  11. X-ray Crystal Structure of the B Component of Hemolysin BL from Bacillus cereus

    Energy Technology Data Exchange (ETDEWEB)

    Madegowda,M.; Eswaramoorthy, S.; Burley, S.; Swaminathan, S.

    2008-01-01

    Bacillus cereus Hemolysin BL enterotoxin, a ternary complex of three proteins, is the causative agent of food poisoning and requires all three components for virulence. The X-ray structure of the binding domain of HBL suggests that it may form a pore similar to other soluble channel forming proteins. A putative pathway of pore formation is discussed.

  12. B-L Violating Proton Decay Modes and New Baryogenesis Scenario in SO(10)

    CERN Document Server

    Babu, K S

    2012-01-01

    We show that grand unified theories based on SO(10) generate quite naturally baryon number violating dimension seven operators that violate (B-L), and lead to novel nucleon decay modes such as n \\to e^-K^+, e^- \\pi^+ and p \\to \

  13. Subcellular Localization and Differentiation-Induced Redistribution of the Protein Tyrosine Phosphatase PTP-BL in Neuroblastoma Cells.

    NARCIS (Netherlands)

    Ham, M. van der; Kemperman, L.; Wijers-Rouw, M.J.P.; Fransen, J.; Hendriks, W.J.A.J.

    2005-01-01

    1.In cells of epithelial origin the protein tyrosine phosphatase PTP-BL is predominantly localized at the apical membrane of polarized cells. This large submembranous multidomain PTP is also expressed in cells of neuronal origin. We studied the localization of PTP-BL in mouse neuroblastoma cells uti

  14. Detection of the specific antigens in the tissues of the C57BL/6 mouses infected with hantavirus%汉坦病毒感染C57BL/6小鼠组织中特异性抗原的检测

    Institute of Scientific and Technical Information of China (English)

    程林峰; 白露; 李凯; 李璞媛; 胡刚; 于澜; 吴兴安; 徐志凯; 张芳琳

    2011-01-01

    Objective To establish a system to evaluate the animals infected with hantavirus. Methods C57BL/6 mice were intramuscular infected with various doses of hantavirus ( 10-1 to 10-2 dilution of stock solution). Viral antigen in the mouse tissues was detected by ELISA method at day-3, 6, 9, 12, and 15 after infection. Results Viral antigens could be detected from the liver and spleen samples early after infection. The expression level was reduced gradually. Conclusion The results provided some information about the animals infected with hantavirus.%目的 通过检测汉坦病毒感染C57BL/6小鼠组织中特异性病毒抗原,以建立汉坦病毒感染动物的评价体系.方法 将汉坦病毒陈株按照原病毒液、10-1、10-2三个滴度经肌肉注射感染C57BL/6小鼠,在感染后的第3、6、9、12、15天,分别取小鼠的心、肝、脾、肺、肾、脑等组织研磨后制成病毒悬液,以ELISA法检测各组织中的病毒特异性抗原.结果 C57BL/6小鼠感染汉坦病毒后短期内在其肝脏和脾脏可以检测到特异性抗原,随着时间的延长,这些抗原逐步消失.结论 上述结果为建立汉坦病毒感染动物的评价体系提供了一种参考.

  15. Automatic object recognition

    Science.gov (United States)

    Ranganath, H. S.; Mcingvale, Pat; Sage, Heinz

    1988-01-01

    Geometric and intensity features are very useful in object recognition. An intensity feature is a measure of contrast between object pixels and background pixels. Geometric features provide shape and size information. A model based approach is presented for computing geometric features. Knowledge about objects and imaging system is used to estimate orientation of objects with respect to the line of sight.

  16. Object oriented methods

    CERN Document Server

    Graham, Ian

    1994-01-01

    This book is a revision of Ian Graham's successful survey of the whole area of object technology. It covers object- oriented programming, object-oriented design, object- oriented analysis, object-oriented databases and treats several related technologies. New to this edition are more applications of object-oriented methods and more coverage of object-oriented database products available. Graham has also doubled the design and analysis material that examines over 60 different approaches - making this the most comprehensive book on the market. Also new is the foreword by Grady Booch.

  17. Junctional adhesion molecule (JAM)-C deficient C57BL/6 mice develop a severe hydrocephalus.

    Science.gov (United States)

    Wyss, Lena; Schäfer, Julia; Liebner, Stefan; Mittelbronn, Michel; Deutsch, Urban; Enzmann, Gaby; Adams, Ralf H; Aurrand-Lions, Michel; Plate, Karl H; Imhof, Beat A; Engelhardt, Britta

    2012-01-01

    The junctional adhesion molecule (JAM)-C is a widely expressed adhesion molecule regulating cell adhesion, cell polarity and inflammation. JAM-C expression and function in the central nervous system (CNS) has been poorly characterized to date. Here we show that JAM-C(-/-) mice backcrossed onto the C57BL/6 genetic background developed a severe hydrocephalus. An in depth immunohistochemical study revealed specific immunostaining for JAM-C in vascular endothelial cells in the CNS parenchyma, the meninges and in the choroid plexus of healthy C57BL/6 mice. Additional JAM-C immunostaining was detected on ependymal cells lining the ventricles and on choroid plexus epithelial cells. Despite the presence of hemorrhages in the brains of JAM-C(-/-) mice, our study demonstrates that development of the hydrocephalus was not due to a vascular function of JAM-C as endothelial re-expression of JAM-C failed to rescue the hydrocephalus phenotype of JAM-C(-/-) C57BL/6 mice. Evaluation of cerebrospinal fluid (CSF) circulation within the ventricular system of JAM-C(-/-) mice excluded occlusion of the cerebral aqueduct as the cause of hydrocephalus development but showed the acquisition of a block or reduction of CSF drainage from the lateral to the 3(rd) ventricle in JAM-C(-/-) C57BL/6 mice. Taken together, our study suggests that JAM-C(-/-) C57BL/6 mice model the important role for JAM-C in brain development and CSF homeostasis as recently observed in humans with a loss-of-function mutation in JAM-C.

  18. Junctional adhesion molecule (JAM-C deficient C57BL/6 mice develop a severe hydrocephalus.

    Directory of Open Access Journals (Sweden)

    Lena Wyss

    Full Text Available The junctional adhesion molecule (JAM-C is a widely expressed adhesion molecule regulating cell adhesion, cell polarity and inflammation. JAM-C expression and function in the central nervous system (CNS has been poorly characterized to date. Here we show that JAM-C(-/- mice backcrossed onto the C57BL/6 genetic background developed a severe hydrocephalus. An in depth immunohistochemical study revealed specific immunostaining for JAM-C in vascular endothelial cells in the CNS parenchyma, the meninges and in the choroid plexus of healthy C57BL/6 mice. Additional JAM-C immunostaining was detected on ependymal cells lining the ventricles and on choroid plexus epithelial cells. Despite the presence of hemorrhages in the brains of JAM-C(-/- mice, our study demonstrates that development of the hydrocephalus was not due to a vascular function of JAM-C as endothelial re-expression of JAM-C failed to rescue the hydrocephalus phenotype of JAM-C(-/- C57BL/6 mice. Evaluation of cerebrospinal fluid (CSF circulation within the ventricular system of JAM-C(-/- mice excluded occlusion of the cerebral aqueduct as the cause of hydrocephalus development but showed the acquisition of a block or reduction of CSF drainage from the lateral to the 3(rd ventricle in JAM-C(-/- C57BL/6 mice. Taken together, our study suggests that JAM-C(-/- C57BL/6 mice model the important role for JAM-C in brain development and CSF homeostasis as recently observed in humans with a loss-of-function mutation in JAM-C.

  19. Organ culture of C57BL/6 mouse arteries with LPS as an in vitro model of vascular inflammation

    DEFF Research Database (Denmark)

    Outzen, Emilie Middelbo; Mehryar, Rahila; Boonen, Harrie C.M.

    57BL/6 MA along with increased expression of inflammatory markers in aorta. Conclusions: In C57BL/6 MA, maximum active wall tension was achieved with a normalisation factor of 0.9. Furthermore, organ culture with LPS induces vascular inflammation and functional changes in C57BL/6 arteries...... an in vitro model for studying vascular inflammation and function in cultured arteries from C57BL/6 mice. Methods: Segments of abdominal aorta and mesenteric arteries (MA) were incubated for 24 hours at 37̊C and 95% O2/5% CO2 in DMEM ± 100 ng/mL LPS. Aorta segments were frozen for molecular studies...... of inflammatory markers. MA segments were mounted in tissue baths for measurement of isometric contractile force. Functional studies of MA included characterisation of length-tension relationship and pharmacological reactivity to selected agonists. Results and discussion: Maximum active wall tension of C57BL/6 MA...

  20. Molecular replacement studies on crystal structure of DesBl-B2 Despentapeptide (B26-B30) insulin

    Institute of Scientific and Technical Information of China (English)

    刁家升; 万柱礼; 常文瑞; 梁栋材

    1997-01-01

    Using the crystal structure of Despentapeptide (B26-B30) insulin (DPI) as the search model, the crystal structure of DesBl-B2 Despentapeptide (B26-B30) insulin (DesBl-2 DPI) has been studied by the molecular replacement method. There is one DesBl-2 DPI molecule in each crystallographic asymmetric unit. The cross rotation function search and the translation function search show apparent peaks and thus determine the orientation and position of DesBl-2 DPI molecule in the cell respectively. The subsequent three-dimensional structural rebuilding and refine-ment of DesBl-2 DPI molecule confirm the results by molecular replacement method.

  1. Object reading: text recognition for object recognition

    NARCIS (Netherlands)

    Karaoglu, S.; van Gemert, J.C.; Gevers, T.

    2012-01-01

    We propose to use text recognition to aid in visual object class recognition. To this end we first propose a new algorithm for text detection in natural images. The proposed text detection is based on saliency cues and a context fusion step. The algorithm does not need any parameter tuning and can d

  2. Defining Learning Objectives

    Institute of Scientific and Technical Information of China (English)

    霍鑫红

    2014-01-01

    <正>This article attempts to introduce the teacher to developments in the area of specifying learning objectives.When you have studied this article carefully,you should be able to(a)distinguish between statements of aims and statements of objectives,(b)discuss the merits of writing objectives from the point of view of the learner,and(c)write both complete and abbreviated statements of learning objectives for different language skills,functions,and notions.

  3. Metabolic deficiences revealed in the biotechnologically important model bacterium Escherichia coli BL21(DE3.

    Directory of Open Access Journals (Sweden)

    Constanze Pinske

    Full Text Available The Escherichia coli B strain BL21(DE3 has had a profound impact on biotechnology through its use in the production of recombinant proteins. Little is understood, however, regarding the physiology of this important E. coli strain. We show here that BL21(DE3 totally lacks activity of the four [NiFe]-hydrogenases, the three molybdenum- and selenium-containing formate dehydrogenases and molybdenum-dependent nitrate reductase. Nevertheless, all of the structural genes necessary for the synthesis of the respective anaerobic metalloenzymes are present in the genome. However, the genes encoding the high-affinity molybdate transport system and the molybdenum-responsive transcriptional regulator ModE are absent from the genome. Moreover, BL21(DE3 has a nonsense mutation in the gene encoding the global oxygen-responsive transcriptional regulator FNR. The activities of the two hydrogen-oxidizing hydrogenases, therefore, could be restored to BL21(DE3 by supplementing the growth medium with high concentrations of Ni²⁺ (Ni²⁺-transport is FNR-dependent or by introducing a wild-type copy of the fnr gene. Only combined addition of plasmid-encoded fnr and high concentrations of MoO₄²⁻ ions could restore hydrogen production to BL21(DE3; however, to only 25-30% of a K-12 wildtype. We could show that limited hydrogen production from the enzyme complex responsible for formate-dependent hydrogen evolution was due solely to reduced activity of the formate dehydrogenase (FDH-H, not the hydrogenase component. The activity of the FNR-dependent formate dehydrogenase, FDH-N, could not be restored, even when the fnr gene and MoO₄²⁻ were supplied; however, nitrate reductase activity could be recovered by combined addition of MoO₄²⁻ and the fnr gene. This suggested that a further component specific for biosynthesis or activity of formate dehydrogenases H and N was missing. Re-introduction of the gene encoding ModE could only partially restore the

  4. 近交系小鼠C57BL/6和C57BL/10的转录组差异研究%Transcriptome profile difference between C57BL/6 and C57BL/10 inbred mouse strains

    Institute of Scientific and Technical Information of China (English)

    陈航; 岳秉飞

    2016-01-01

    目的:对近交系小鼠C57BL/6和C57BL/10进行转录组测序,对比其转录组差异,发现免疫反应相关差异基因,为药物体内活性评价动物选择提供参考.方法:采用Illumina Hiseq 2000测序平台进行测序,通过短序列分析获取转录本,通过基因功能分类(GO)和京都基因与基因组百科全书(KEGG)数据库进行测序结果分析.结果:获得38 553 614个C57BL/6小鼠的原始序列和37 721 318个C57BL/10小鼠的原始序列.获得118 002个转录本,注释了46 193个差异基因.38 106个转录本注释到2 196个GO分类中,GO分类主要分为3类:细胞成分,分子功能和生物过程.1 600个转录本注释到254个KEGG通路中.另外,发现了4 651个单核苷酸(SNP)位点.结论:通过二代测序方法发现近交系小鼠C57BL/6和C57BL/10转录组存在显著差异基因.在KEGG通路分析中筛选了一系列与小鼠免疫应答相关的差异基因,为建立小鼠免疫评价模型积累了数据,对药物实验动物体内活性检测分析具有参考意义,为生物制品评价用实验动物的标准化提供技术支撑.

  5. Ownership and Object History

    Science.gov (United States)

    Friedman, Ori; Neary, Karen R.; Defeyter, Margaret A.; Malcolm, Sarah L.

    2011-01-01

    Appropriate behavior in relation to an object often requires judging whether it is owned and, if so, by whom. The authors propose accounts of how people make these judgments. Our central claim is that both judgments often involve making inferences about object history. In judging whether objects are owned, people may assume that artifacts (e.g.,…

  6. Objects in Motion

    Science.gov (United States)

    Damonte, Kathleen

    2004-01-01

    One thing scientists study is how objects move. A famous scientist named Sir Isaac Newton (1642-1727) spent a lot of time observing objects in motion and came up with three laws that describe how things move. This explanation only deals with the first of his three laws of motion. Newton's First Law of Motion says that moving objects will continue…

  7. Birth of the Object: Detection of Objectness and Extraction of Object Shape through Object Action Complexes

    DEFF Research Database (Denmark)

    Kraft, Dirk; Pugeault, Nicolas; Baseski, Emre;

    2008-01-01

    interact. First, by making use of an object independent grasping mechanism, physical control over potential objects can be gained. Having evaluated the initial grasping mechanism as being successful, a second behavior extracts the object shape by making use of prediction based on the motion induced...

  8. Survivability via Control Objectives

    Energy Technology Data Exchange (ETDEWEB)

    CAMPBELL,PHILIP L.

    2000-08-11

    Control objectives open an additional front in the survivability battle. A given set of control objectives is valuable if it represents good practices, it is complete (it covers all the necessary areas), and it is auditable. CobiT and BS 7799 are two examples of control objective sets.

  9. Learning Objects and Gerontology

    Science.gov (United States)

    Weinreich, Donna M.; Tompkins, Catherine J.

    2006-01-01

    Virtual AGE (vAGE) is an asynchronous educational environment that utilizes learning objects focused on gerontology and a learning anytime/anywhere philosophy. This paper discusses the benefits of asynchronous instruction and the process of creating learning objects. Learning objects are "small, reusable chunks of instructional media" Wiley…

  10. On the Crime Object

    Science.gov (United States)

    Akutaev, Rasul M.; Magomedov, Guseyn B.

    2016-01-01

    The relevance of the research of this problem is caused by the theoretical and practical needs of a specific concept of the crime object as one of the corpus delicti signs essentially the determining and defining its object and objective side, thereby--the nature of socially dangerous act. Besides, being a facultative sign of corpus delicti, the…

  11. Isolation of Epstein-Barr virus (EBV)-negative cell clones from the EBV-positive Burkitt's lymphoma (BL) line Akata: malignant phenotypes of BL cells are dependent on EBV.

    OpenAIRE

    1994-01-01

    During cultivation of the Epstein-Barr virus (EBV)-positive Burkitt's lymphoma (BL) line Akata, it was noted that EBV DNA is lost from some of the cells. Isolation of EBV-positive and EBV-negative clones with the same origin made it possible to examine the effects of EBV in BL cells. The results indicate that malignant phenotypes of BL, such as growth in low serum, anchorage-independent growth in soft agar, and tumorigenicity in nude mice, are dependent on the presence of EBV genomes and unde...

  12. Allogeneic Bone Marrow Transplant from MRL/MpJ Super-Healer Mice Does Not Improve Articular Cartilage Repair in the C57Bl/6 Strain.

    Directory of Open Access Journals (Sweden)

    Catherine A Leonard

    Full Text Available Articular cartilage has been the focus of multiple strategies to improve its regenerative/ repair capacity. The Murphy Roths Large (MRL/MpJ "super-healer" mouse demonstrates an unusual enhanced regenerative capacity in many tissues and provides an opportunity to further study endogenous cartilage repair. The objective of this study was to test whether the super-healer phenotype could be transferred from MRL/MpJ to non-healer C57Bl/6 mice by allogeneic bone marrow transplant.The healing of 2mm ear punches and full thickness cartilage defects was measured 4 and 8 weeks after injury in control C57Bl/6 and MRL/MpJ "super-healer" mice, and in radiation chimeras reconstituted with bone marrow from the other mouse strain. Healing was assessed using ear hole diameter measurement, a 14 point histological scoring scale for the cartilage defect and an adapted version of the Osteoarthritis Research Society International scale for assessment of osteoarthritis in mouse knee joints.Normal and chimeric MRL mice showed significantly better healing of articular cartilage and ear wounds along with less severe signs of osteoarthritis after cartilage injury than the control strain. Contrary to our hypothesis, however, bone marrow transplant from MRL mice did not confer improved healing on the C57Bl/6 chimeras, either in regards to ear wound healing or cartilage repair.The elusive cellular basis for the MRL regenerative phenotype still requires additional study and may possibly be dependent on additional cell types external to the bone marrow.

  13. Identification of human cytomegalovirus phosphoprotein 65 in C57BL/6 and BXSB mice as a potential trigger of systemic lupus erythematosus related serum markers

    Institute of Scientific and Technical Information of China (English)

    Yuan; Zhang; Ting-Ting; Jia; Yang; Pan; Wen-Li; Li; Yu; Sun; Jin-Ming; Li; Lu-Nan; Wang

    2015-01-01

    Objective:To investigate the potential role of human cytomegalovirus lower matrix phosphoprotein 65(HCMV-pp65) in murine systemic lupus erythematosus(SLE).Methods:The prokaryotic plasmid pET-28b-pp65 was constructed to express the HCMVpp65 protein.BXSB mice and C57BL/6 mice were inoculated with pp65 eukarvotic plasmid pcDNA3.0-pp65 intramuscularly 5 times at 2-week intervals,and then the blood of the mice was subsequently collected via the retro-orbital vein.Indirect ELISAs were used to evaluate the concentration of anti-pp65 immunoglobulin G,anti-double-stranded DNA and antinuclear antibodies.lnterleukin-1β and tumor necrosis factor-α were also determined by competitive ELISA.At the same time,3 major SLE-related circulating microRNAs were examined by quantitative RT-PCR.Results:The early production of autoantibodies was observed in pp65-immunized male BXSB as well as C57BL/6 mice.Overexpression of interleukin-1β and tumor necrosis factor-a were detected in pp65-immunized male BXSB mice.Quantitative RT-PCR analyses showed that three SLE related microRNAs(microRNA-126,microRNA-125 a,and microRKA-146a) were dovvnrcgulatcd in peripheral blood mononuclear cells of pp65-immunizcd mice.Conclusions:Our findings indicate that HCMV-pp65 immunization strongly triggers the development and progression of" SLE-like disease in both BXSB and C57BL/6 mice,which indicates that the immune responses induced by HCMV-pp65 may be involved in the development of SLE.

  14. Extracts of pomelo peels prevent high-fat diet-induced metabolic disorders in c57bl/6 mice through activating the PPARα and GLUT4 pathway.

    Directory of Open Access Journals (Sweden)

    Xiaobo Ding

    Full Text Available OBJECTIVE: Metabolic syndrome is a serious health problem in both developed and developing countries. The present study investigated the anti-metabolic disorder effects of different pomelo varieties on obese C57BL/6 mice induced by high-fat (HF diet. DESIGN: The peels of four pomelo varieties were extracted with ethanol and the total phenols and flavonoids content of these extracts were measured. For the animal experiment, the female C57BL/6 mice were fed with a Chow diet or a HF diet alone or supplemented with 1% (w/w different pomelo peel extracts for 8 weeks. Body weight and food intake were measured every other day. At the end of the treatment, the fasting blood glucose, glucose tolerance and insulin (INS tolerance test, serum lipid profile and insulin levels, and liver lipid contents were analyzed. The gene expression analysis was performed with a quantitative real-time PCR assay. RESULT: The present study showed that the Citrus grandis liangpinyou (LP and beibeiyou (BB extracts were more potent in anti-metabolic disorder effects than the duanshiyou (DS and wubuyou (WB extracts. Both LP and BB extracts blocked the body weight gain, lowered fasting blood glucose, serum TC, liver lipid levels, and improved glucose tolerance and insulin resistance, and lowered serum insulin levels in HF diet-fed mice. Compared with the HF group, LP and BB peel extracts increased the mRNA expression of PPARα and its target genes, such as FAS, PGC-1α and PGC-1β, and GLUT4 in the liver and white adipocyte tissue (WAT. CONCLUSION: We found that that pomelo peel extracts could prevent high-fat diet-induced metabolic disorders in C57BL/6 mice through the activation of the PPARα and GLUT4 signaling. Our results indicate that pomelo peels could be used as a dietary therapy and the potential source of drug for metabolic disorders.

  15. Per Object statistical analysis

    DEFF Research Database (Denmark)

    2008-01-01

    Variable. This procedure was developed in order to be able to export objects as ESRI shape data with the 90-percentile of the Hue of each object's pixels as an item in the shape attribute table. This procedure uses a sub-level single pixel chessboard segmentation, loops for each of the objects......This RS code is to do Object-by-Object analysis of each Object's sub-objects, e.g. statistical analysis of an object's individual image data pixels. Statistics, such as percentiles (so-called "quartiles") are derived by the process, but the return of that can only be a Scene Variable, not an Object...... of a specific class in turn, and uses as pair of PPO stages to derive the statistics and then assign them to the objects' Object Variables. It may be that this could all be done in some other, simply way, but several other ways that were tried did not succeed. The procedure ouptut has been tested against...

  16. Early object relations into new objects.

    Science.gov (United States)

    Downey, T W

    2001-01-01

    Two strands of change are suggested by this review, one maturational, the other therapeutic or developmental (Hartmann and Kris, 1945). By "maturational" I mean to suggest energies that infuse the individual from earliest life in a manner that includes object relations, but for the healthy exercise of which object relations per se need not be of central and crucial importance. Within wide limits such energies may be delayed until growth conditions prevail without significant distortion of certain of the organism's ego functions. Therapeutic change is analogous to developmental change in that both involve the crucial presence of another to release energies. In therapeutic change these are energies that have been repressed beyond the reach of developmental dynamics. In everyday development crisis and synthesis alternate in conjunction with new and emerging objects to add to the psychological structures brought to the fore by maturation. In many instances, as we see with John, over time and in a less focussed manner, developmental changes can approximate therapeutic change and visa versa. Freud-Dann in their "experiment" pursued one line, in which the equipmental delay brought on by extremely adverse living circumstances was redressed by providing an interpersonally enriching, loving, developmentally facilitating milieu. The sketches of individual children and John's subsequent story provide a perspective into what becomes the stuff of growth and what remains the stuff of neurosis. The developmental reserves and ego resilience of these children were impressive but probably not extraordinary. Usual growth ensued as soon as they were provided with the rich soil of Bulldogs Bank instead of the desert sand of the Tereszin concentration camp. However, no one can escape such adverse circumstances without having taken in the stuff of neurosis. Affects and percepts that were not assimilatable or even available to consciousness at the time remain buried in the unconscious

  17. Hydrolyzed casein reduces diet-induced obesity in male C57BL/6J mice

    DEFF Research Database (Denmark)

    Lillefosse, Haldis Haukås; Tastesen, Hanne Sørup; Du, Zhen-Yu;

    2013-01-01

    The digestion rate of dietary protein is a regulating factor for postprandial metabolism both in humans and animal models. However, few data exist about the habitual consumption of proteins with different digestion rates with regard to the development of body mass and diet-induced obesity. Here, we...... used a factorial ANOVA design to investigate the effects of protein form (intact vs. hydrolyzed casein) and protein level (16 vs. 32 energy percent protein) on body mass gain and adiposity in obesity-prone male C57BL/6J mice fed Western diets with 35 energy percent fat. Mice fed the hydrolyzed casein...... by hydrolyzed casein ingestion translated into decreased body and adipose tissue masses. We conclude that chronic consumption of extensively hydrolyzed casein reduces body mass gain and diet-induced obesity in male C57BL/6J mice....

  18. Atomki anomaly and dark matter in a radiative seesaw model with gauged $B-L$ symmetry

    CERN Document Server

    Seto, Osamu

    2016-01-01

    Motivated by recently reported anomalies in a decay of an excited state of beryllium by the Atomki collaboration, we study a radiative seesaw model with gauged $B-L$ symmetry and a $Z_2$ parity. Assuming that the anomalies originate from the decay of the $B-L$ gauge boson followed by the nuclear decay, the mass of the lightest right-handed neutrino or the dark matter candidate can be determined below $10$ GeV. We show that for this mass range, the model can explain the anomalies in the beryllium decay and the relic dark matter abundance consistent with neutrino masses. We also predict its spin-independent cross section in direct detection experiments for this mass range.

  19. Identification of salt-tolerant Sinorhizobium sp. strain BL3 membrane proteins based on proteomics

    DEFF Research Database (Denmark)

    Tanthanuch, Waraporn; Tittabutr, Panlada; Mohammed, Shabaz;

    2010-01-01

    Sinorhizobium sp. BL3 is a salt-tolerant strain that can fix atmospheric nitrogen in symbiosis with leguminous host plants under salt-stress conditions. Since cell membranes are the first barrier to environmental change, it is interesting to explore the membrane proteins within this protective......-line SCX fractionation coupled to nanoLC-MS/MS. These techniques would be useful for further comparative analysis of membrane proteins that function in the response to environmental stress....... barrier under salt stress. The protein contents of membrane-enriched fractions obtained from BL3 were analyzed by nanoflow liquid chromatography interfaced with electrospray ionization tandem mass spectrometry. A total of 105 membrane proteins were identified. These proteins could be classified into 17...

  20. Muon Anomalous Magnetic Moment in SUSY B-L Model with Inverse Seesaw

    CERN Document Server

    Khalil, Shaaban

    2015-01-01

    Motivated by the tension between the Higgs mass and muon g-2 in minimal supersymmetric standard model (MSSM), we analyze the muon g-2 in supersymmertic B-L extension of the standard model (BLSSM) with inverse seesaw mechanism. In this model, the Higgs mass receives extra important radiative corrections proportional to large neutrino Yukawa coupling. We point out that muon g-2 also gets significant contribution, due to the constructive interferences of light neutralino effects. The light neutralinos are typically the MSSM Bino like and the supersymmetric partner of U(1)_B-L gauge boson (B'-ino). We show that with universal soft supersymmetry breaking terms, the muon g-2 resides within 2 sigma of the measured value, namely ~17 x 10^-10, with Higgs mass equal to 125 GeV .

  1. Segmentation of the C57BL/6J mouse cerebellum in magnetic resonance images.

    Science.gov (United States)

    Ullmann, Jeremy F P; Keller, Marianne D; Watson, Charles; Janke, Andrew L; Kurniawan, Nyoman D; Yang, Zhengyi; Richards, Kay; Paxinos, George; Egan, Gary F; Petrou, Steven; Bartlett, Perry; Galloway, Graham J; Reutens, David C

    2012-09-01

    The C57BL mouse is the centerpiece of efforts to use gene-targeting technology to understand cerebellar pathology, thus creating a need for a detailed magnetic resonance imaging (MRI) atlas of the cerebellum of this strain. In this study we present a methodology for systematic delineation of the vermal and hemispheric lobules of the C57BL/6J mouse cerebellum in magnetic resonance images. We have successfully delineated 38 cerebellar and cerebellar-related structures. The higher signal-to-noise ratio achieved by group averaging facilitated the identification of anatomical structures. In addition, we have calculated average region volumes and created probabilistic maps for each structure. The segmentation method and the probabilistic maps we have created will provide a foundation for future studies of cerebellar disorders using transgenic mouse models.

  2. Medieindustri og blå blok i parløb mod DR

    DEFF Research Database (Denmark)

    Hjarvard, Stig

    2016-01-01

    Et parløb mellem private medieinteresser og blå blok kan svække public service i almindelighed og DR i særdeleshed, potentielt den største svækkelse af DR siden monopolbruddet i 1988. Men hvorfor vil man svække en offentlig mediesucces i en situation, hvor det private mediemarked er voksende?...

  3. Objects, materiality and meaning

    DEFF Research Database (Denmark)

    Lenau, Torben Anker; Lindegaard, Hanne

    2008-01-01

    The present research work investigates the relation between physical objects, their materiality, understood as the physical substances they are made from, and the communication from the objects. In product design of physical objects the communicative aspects are just as important as the function ...... be written into the object. The materials are therefore carriers of communication, even though this is dependent of the cultural context and the environment which the object will be part of. However the designer has only minor influence on those.......The present research work investigates the relation between physical objects, their materiality, understood as the physical substances they are made from, and the communication from the objects. In product design of physical objects the communicative aspects are just as important as the function...... of the object, and the designers aim is therefore to tune both in order to achieve a desired goal. To do so the designer basically has 2 options: Alteration of the physical shape of the object and the selection of materials. Through the manipulation of shape and materials can symbolic and sensory information...

  4. Surface and interface analysis of nanomaterials at microfocus beamline (BL-16) of Indus-2

    Science.gov (United States)

    Das, Gangadhar; Khooha, Ajay; Kane, S. R.; Singh, A. K.; Tiwari, M. K.

    2016-05-01

    Analysis of chemical nature and electronic structure at the interface of a thin film medium is important in many technological applications as well as to understand overall efficiency of a thin film device. Synchrotron radiation based x-ray spectroscopy is a promising technique to study interface nature of the nanomaterials with atomic resolutions. A combined x-ray reflectivity and grazing incidence x-ray fluorescence measurement facility has been recently constructed at the BL-16 microfocus beamline of Indus-2 synchrotron facility to accomplish surface-interface microstructural characterization of thin layered materials. It is also possible to analyze contaminates or adsorbed ad-atoms on the surface of the thin nanostructure materials. The BL-16 beamline also provides an attractive platform to perform a variety of analytical research activities especially in the field of micro x-ray fluorescence and ultra-trace elements analysis using Synchrotron radiation. We describe various salient features of the BL-16 reflectometer experimental station and the detailed description of its capabilities through the measured results, obtained for various thin layered nanomaterials.

  5. Why are some BL Lacs detected by \\fermi, but others not ?

    CERN Document Server

    Wu, Zhongzu; Gu, Minfeng; Chen, Liang

    2014-01-01

    By cross-correlating an archival sample of 170 BL Lacs with 2 year \\fermilat AGN sample, we have compiled a sample of 100 BL Lacs with \\fermi detection (FBLs), and a sample of 70 non-\\fermi BL Lacs (NFBLs). We compared various parameters of FBLs with those of NFBLs, including the redshift, the low frequency radio luminosity at 408 MHz ($L_{\\rm 408MHz}$), the absolute magnitude of host galaxies ($M_{\\rm host}$), the polarization fraction from NVSS survey ($P_{\\rm NVSS}$), the observed arcsecond scale radio core flux at 5 GHz ($F_{\\rm core}$) and jet Doppler factor; all the parameters are directly \\textbf{measured} or derived from available data from literatures. We found that the Doppler factor is on average larger in FBLs than in NFBLs, and the $Fermi~ \\gamma$-ray detection rate is higher in sources with higher Doppler factor. In contrast, there are no significant differences in terms of the intrinsic parameters of redshift, $ L_{\\rm 408MHz}$, $ M_{\\rm host}$ and $ P_{\\rm NVSS}$. FBLs seem to have a higher pr...

  6. Identification of mutations through dominant screening for obesity using C57BL/6 substrains

    Science.gov (United States)

    Hossain, Mohammad Sarowar; Asano, Fuyuki; Fujiyama, Tomoyuki; Miyoshi, Chika; Sato, Makito; Ikkyu, Aya; Kanno, Satomi; Hotta, Noriko; Kakizaki, Miyo; Honda, Takato; Kim, Staci J.; Komiya, Haruna; Miura, Ikuo; Suzuki, Tomohiro; Kobayashi, Kimio; Kaneda, Hideki; Kumar, Vivek; Takahashi, Joseph S.; Wakana, Shigeharu; Funato, Hiromasa; Yanagisawa, Masashi

    2016-01-01

    The discovery of leptin substantiated the usefulness of a forward genetic approach in elucidating the molecular network regulating energy metabolism. However, no successful dominant screening for obesity has been reported, which may be due to the influence of quantitative trait loci between the screening and counter strains and the low fertility of obese mice. Here, we performed a dominant screening for obesity using C57BL/6 substrains, C57BL/6J and C57BL/6N, with the routine use of in vitro fertilization. The screening of more than 5000 mutagenized mice established two obese pedigrees in which single nucleotide substitutions in Mc4r and Sim1 genes were identified through whole-exome sequencing. The mutation in the Mc4r gene produces a premature stop codon, and the mutant SIM1 protein lacks transcriptional activity, showing that the haploinsufficiency of SIM1 and MC4R results in obesity. We further examined the hypothalamic neuropeptide expressions in the mutant pedigrees and mice with diet-induced obesity, which showed that each obesity mouse model has distinct neuropeptide expression profiles. This forward genetic screening scheme is useful and applicable to any research field in which mouse models work. PMID:27585985

  7. EXPERIMENTAL SUBCUTANEOUS CYSTICERCOSIS BY Taenia crassiceps IN BALB/c AND C57BL/6 MICE

    Directory of Open Access Journals (Sweden)

    Íria Márcia PEREIRA

    2016-01-01

    Full Text Available SUMMARY Human cysticercosis is one of the most severe parasitic infections affecting tissues. Experimental models are needed to understand the host-parasite dynamics involved throughout the course of the infection. The subcutaneous experimental model is the closest to what is observed in human cysticercosis that does not affect the central nervous system. The aim of this study was to evaluate macroscopically and microscopically the experimental subcutaneous cysticercosis caused by Taenia crassiceps cysticerci in BALB/c and C57BL/6 mice. Animals were inoculated in the dorsal subcutaneous region and macroscopic and microscopic aspects of the inflammatory process in the host-parasite interface were evaluated until 90 days after the inoculation (DAI. All the infected animals presented vesicles containing cysticerci in the inoculation site, which was translucent at 7 DAI and then remained opaque throughout the experimental days. The microscopic analysis showed granulation tissue in BALB/c mice since the acute phase of infection evolving to chronicity without cure, presenting 80% of larval stage cysticerci at 90 DAI. While C57BL/6 mice presented 67% of final stage cysticerci at 90 DAI, the parasites were surrounded by neutrophils evolving to the infection control. It is possible to conclude that the genetic features of susceptibility (BALB/c or resistance (C57BL/6 were confirmed in an experimental subcutaneous model of cysticercosis.

  8. EXPERIMENTAL SUBCUTANEOUS CYSTICERCOSIS BY Taenia crassiceps IN BALB/c AND C57BL/6 MICE.

    Science.gov (United States)

    Pereira, Íria Márcia; Lima, Sarah Buzaim; Freitas, Aline de Araújo; Vinaud, Marina Clare; Junior, Ruy de Souza Lino

    2016-07-11

    Human cysticercosis is one of the most severe parasitic infections affecting tissues. Experimental models are needed to understand the host-parasite dynamics involved throughout the course of the infection. The subcutaneous experimental model is the closest to what is observed in human cysticercosis that does not affect the central nervous system. The aim of this study was to evaluate macroscopically and microscopically the experimental subcutaneous cysticercosis caused by Taenia crassiceps cysticerci in BALB/c and C57BL/6 mice. Animals were inoculated in the dorsal subcutaneous region and macroscopic and microscopic aspects of the inflammatory process in the host-parasite interface were evaluated until 90 days after the inoculation (DAI). All the infected animals presented vesicles containing cysticerci in the inoculation site, which was translucent at 7 DAI and then remained opaque throughout the experimental days. The microscopic analysis showed granulation tissue in BALB/c mice since the acute phase of infection evolving to chronicity without cure, presenting 80% of larval stage cysticerci at 90 DAI. While C57BL/6 mice presented 67% of final stage cysticerci at 90 DAI, the parasites were surrounded by neutrophils evolving to the infection control. It is possible to conclude that the genetic features of susceptibility (BALB/c) or resistance (C57BL/6) were confirmed in an experimental subcutaneous model of cysticercosis.

  9. The C57BL/6J mouse exhibits sporadic congenital portosystemic shunts.

    Directory of Open Access Journals (Sweden)

    Cristina Cudalbu

    Full Text Available C57BL/6 mice are the most widely used strain of laboratory mice. Using in vivo proton Magnetic Resonance Spectroscopy ((1H MRS, we have repeatedly observed an abnormal neurochemical profile in the brains of both wild-type and genetically modified mice derived from the C57BL/6J strain, consisting of a several fold increase in cerebral glutamine and two fold decrease in myo-inositol. This strikingly abnormal neurochemical "phenotype" resembles that observed in chronic liver disease or portosystemic shunting and appeared to be independent of transgene, origin or chow and was not associated with liver failure. As many as 25% of animals displayed the abnormal neurochemical profile, questioning the reliability of this model for neurobiology. We conducted an independent study to determine if this neurochemical profile was associated with portosystemic shunting. Our results showed that 100% of the mice with high brain glutamine displayed portosystemic shunting by concomitant portal angiography while all mice with normal brain glutamine did not. Since portosystemic shunting is known to cause alterations in gene expression in many organs including the brain, we conclude that portosystemic shunting may be the most significant problem associated with C57BL/6J inbreeding both for its effect on the central nervous system and for its systemic repercussions.

  10. Lycopene pretreatment improves hepatotoxicity induced by acetaminophen in C57BL/6 mice.

    Science.gov (United States)

    Bandeira, Ana Carla Balthar; da Silva, Rafaella Cecília; Rossoni, Joamyr Victor; Figueiredo, Vivian Paulino; Talvani, André; Cangussú, Silvia Dantas; Bezerra, Frank Silva; Costa, Daniela Caldeira

    2017-02-01

    Acetaminophen (APAP) is an antipyretic and analgesic drug that, in high doses, leads to severe liver injury and potentially death. Oxidative stress is an important event in APAP overdose. Researchers are looking for natural antioxidants with the potential to mitigate the harmful effects of reactive oxygen species in different models. Lycopene has been widely studied for its antioxidant properties. The aim of this study was to evaluate the antioxidant potential of lycopene pretreatment in APAP-induced liver injury in C57BL/6 mice. C57BL/6 male mice were divided into the following groups: control (C); sunflower oil (CO); acetaminophen 500mg/kg (APAP); acetaminophen 500mg/kg+lycopene 10mg/kg (APAP+L10), and acetaminophen 500mg/kg+lycopene 100mg/kg (APAP+L100). Mice were pretreated with lycopene for 14 consecutive days prior to APAP overdose. Analyses of blood serum and livers were performed. Lycopene was able to improve redox imbalance, decrease thiobarbituric acid reactive species level, and increase CAT and GSH levels. In addition, it decreased the IL-1β expression and the activity of MMP-2. This study revealed that preventive lycopene consumption in C57BL/6 mice can attenuate the effects of APAP-induced liver injury. Furthermore, by improving the redox state, and thus indicating its potential antioxidant effect, lycopene was also shown to have an influence on inflammatory events.

  11. Conceivability Theses and Objections

    DEFF Research Database (Denmark)

    the thesis is more fashionable in the current debate than defending conceivability as anything but one psychological heuristic device among others with which we form beliefs about modality. In this paper, I shall offer a way of demarcating conceivability theses in a way that offers a concise overview, and I...... will try to provide an overview also of the different objections that have been and are leveled at the conceivability theses. A number of these are problems for an epistemology of modality generally. I will focus on the objections that are peculiar to conceivability theses: the Standard Objection...... and the Uselessness Objection. The Standard Objection targets the second premise in an argument for possibility from conceivability, that what is conceived is possible, typically by offering counterexamples in the form of conceivable impossibilities. The Uselessness Objection targets the first premise in an argument...

  12. Scaled-Free Objects

    CERN Document Server

    Grilliette, Will

    2010-01-01

    Several functional analysts and C*-algebraists have been moving toward a categorical means of understanding normed objects. In this work, I address a primary issue with adapting these abstract concepts to functional analytic settings, the lack of free objects. Using a new object, called a "crutched set", and associated categories, I devise generalized construction of normed objects as a left adjoint functor to a natural forgetful functor. Further, the universal property in each case yields a "scaled-free" mapping property, which extends previous notions of `"free" normed objects. In particular, I construct the following types of scaled-free objects: Banach spaces, Banach algebras, C*-algebras, operator spaces, and operator algebras. In subsequent papers, this scaled-free property, coupled with the associated functorial results, will give rise to a new view of presentation theory for C*-algebras, which inherits many properties and constructions from its algebraic counterpart.

  13. Object Duplicate Detection

    OpenAIRE

    Vajda, Péter

    2011-01-01

    With the technological evolution of digital acquisition and storage technologies, millions of images and video sequences are captured every day and shared in online services. One way of exploring this huge volume of images and videos is through searching a particular object depicted in images or videos by making use of object duplicate detection. Therefore, need of research on object duplicate detection is validated by several image and video retrieva...

  14. Propelling Extended Objects

    Science.gov (United States)

    Humbert, Richard

    2010-01-01

    A force acting on just part of an extended object (either a solid or a volume of a liquid) can cause all of it to move. That motion is due to the transmission of the force through the object by its material. This paper discusses how the force is distributed to all of the object by a gradient of stress or pressure in it, which creates the local…

  15. Kuiper Binary Object Formation

    OpenAIRE

    Nazzario, R. C.; Orr, K.; Covington, C.; Kagan, D.; Hyde, T. W.

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction betw...

  16. 近交系C57BL/6J小鼠的脱毛特征%The features of hair loss in the inbred strain of C57BL/6J

    Institute of Scientific and Technical Information of China (English)

    黄月玲; 侯敏; 戴丽军; 谭小军; 任韵; 叶炳飞; 朴金松; 高蔚樱; 劳淑贞; 周敏仪

    2012-01-01

    目的 了解近交系C57BL/6J小鼠脱毛的性质和脱毛的特征.方法 在各代鼠详细观察记录脱毛出现的时间、状况和缓解情况;利用对照组2对来自不同父母鼠的F1雌雄鼠进行交配实验和回盒饲养实验,观察脱毛和脱毛缓解的特征,在F2小鼠观察脱毛特征的遗传性,对脱毛区域皮肤进行病理分析.结果 脱毛(头、颈或背部)多出现在3~6只同养的雌性鼠中(对照组32.4%,实验组16.3%),脱毛-新毛生长的过程交替进行,交配有缓解脱毛的作用并能维持新毛的生长状态,脱毛的特征可以遗传.皮肤病理显示皮肤各层结构、毛囊和毛囊球上皮无明显病理性改变.结论 脱毛可能是本品系在特定饲养条件下适应环境压力失败及缺乏生理活动的一种表现,具有经过良性、可缓解、特征可遗传等特点.%Objective To characterize the nature and features of hair loss in the inbred strain C57BL/6J. Methods The development, manifestations and improving conditions of hair loss were closely observed and recorded in each generation. Two pairs of F1 female and male offspring that came from two different parental mice were used to mate in order to determine if hair loss would improve and at the same time to confirm if the features of hair loss would pass onto the F2 generation. After mating, the females continued to live with their corresponding sisters in the same cage so as to observe if hair loss would re-occur. The skin with hair loss was processed for pathologic examination. Results Hair loss most frequently developed spontaneously on the head, neck and dorsal areas in female mice that 3 to 6 lived together in the same cage (control group: 32.4%, experimental group: 16.3%). The process of hair loss-hair growth alternated constantly. Hair loss was significantly alleviated by mating, and mating could sustain the growth of hairs that re-grown after loss. The features of hair loss could pass onto the next

  17. Objective-C

    CERN Document Server

    DeVoe, Jiva

    2011-01-01

    A soup-to-nuts guide on the Objective-C programming language. Objective-C is the language behind Cocoa and Cocoa Touch, which is the Framework of applications written for the Macintosh, iPod touch, iPhone, and iPad platforms. Part of the Developer Reference series covering the hottest Apple topics, this book covers everything from the basics of the C language to advanced aspects of Apple development. You'll examine Objective-C and high-level subjects of frameworks, threading, networking, and much more.: Covers the basics of the C language and then quickly moves onto Objective-C and more advanc

  18. 自主运动后BALB/c和C57BL/6小鼠学习记忆行为学指标的分析比较%Learning and memory abilities between BALB/c and C57BL/6 mice after voluntary movement

    Institute of Scientific and Technical Information of China (English)

    刘雪芹; 李睿; 崔佳彬; 陆利; 赵云鹤

    2016-01-01

    BACKGROUND: BALB/c and C57BL/6 mice are two inbred strains, but after voluntary movement, there is no report on how to scientifical y reasonably select behavioral experiment methods and indicators and to evaluate the learning and memory abilities of mice. OBJECTIVE: To analyze and compare the behavioral indicators between BALB/c and C57BL/6 mice fol owing voluntary wheel running, to explore the effect of exercise on learning and memory, and to provide a reference for selecting reasonable behavioral indicators. METHODS: 2.5-month-old BALB/c and C57BL/6 mice were randomly divided into control and voluntary wheel running groups. Independent running wheel movement of mice was recorded with VitalView system. 4 weeks later, newborn neurons were labeled via DCX immunofluorescence. Spatial learning, memory and exploration abilities were compared through new arm test, new object recognition test and Morris water maze test. RESULTS AND CONCLUSION: (1) The mean spontaneous activity of BALB/c mice daily was 2.56 fold of that of C57BL/6 mice during wheel running (P   目的:分析比较自主运动后 BALB/c 和 C57BL/6小鼠与学习记忆相关的行为学指标差异,为探讨运动对学习记忆能力的影响,并选择合理的行为学指标提供参考。  方法:将2.5月龄 BALB/c 和 C57BL/6小鼠分别随机分为对照组和跑轮运动组,应用 VitalView 软件记录小鼠自主跑轮运动。跑轮运动4周后,通过 DCX 免疫荧光染色检测海马新生神经元;新异臂探索实验、新物体识别实验和水迷宫实验分析比较小鼠空间学习记忆和探索能力。  结果与结论:①BALB/c 小鼠平均每天运动量约是 C57BL/6小鼠的2.56倍(P <0.001)。②跑轮运动后两种品系小鼠海马 DCX 阳性细胞数较对照组增多。③跑轮运动后两种品系小鼠探索新异臂和新物体的次数、围绕新异臂和新物体探索的时间和距离均较对照组增高(P <0.001),其中 BALB/c

  19. Extract of Kuding tea prevents high-fat diet-induced metabolic disorders in C57BL/6 mice via liver X receptor (LXR β antagonism.

    Directory of Open Access Journals (Sweden)

    Shengjie Fan

    Full Text Available OBJECTIVE: To investigate the effects of ilex kudingcha C. J. Tseng (kuding tea, a traditional beverage in China, on the metabolic disorders in C57BL/6 mice induced by high-fat diets. DESIGN: For the preventive experiment, the female C57BL/6 mice were fed with a standard diet (Chow, high-fat diet (HF, and high-fat diet mixed with 0.05% ethanol extract of kuding tea (EK for 5 weeks. For the therapeutic experiment, the C57BL/6 mice were fed high-fat diet for 3 months, and then mice were split and EK was given with oral gavages for 2 weeks at 50 mg/day/kg. Body weight and daily food intake amounts were measured. At the end of treatment, the adipocyte images were assayed with a scanning electron microscope, and the fasting blood glucose, glucose tolerance test, serum lipid profile and lipids in the livers were analyzed. A reporter gene assay system was used to test the whether EK could act on nuclear receptor transcription factors, and the gene expression analysis was performed with a quantitative PCR assay. RESULTS: In the preventive treatment, EK blocked the body weight gain, reduced the size of the adipocytes, lowered serum triglyceride, cholesterol, LDL-cholesterol, fasting blood glucose levels and glucose tolerance in high-fat diet-fed C57BL/6 mice. In the therapeutic treatment, EK reduced the size of the white adipocytes, serum TG and fasting blood glucose levels in obese mice. With the reporter assay, EK inhibited LXRβ transactivity and mRNA expression of LXRβ target genes. CONCLUSION: We observed that EK has both preventive and therapeutic roles in metabolic disorders in mice induced with high-fat diets. The effects appear to be mediated through the antagonism of LXRβ transactivity. Our data indicate that kuding tea is a useful dietary therapy and a potential source for the development of novel anti-obesity and lipid lowering drugs.

  20. Effects of tail loss on locomotor ability and selected body temperature of common lizard Lacerta vivipara.%断尾对胎生蜥蜴运动能力和选择体温的影响

    Institute of Scientific and Technical Information of China (English)

    刘鹏; 刘琳琳; 刘志涛; 夏玉国; 计翔; 赵文阁

    2011-01-01

    尾自切是蜥蜴为了降低被捕食危险而采取的一种反捕食适应策略,但断尾可导致体重减轻、热量收支平衡改变,并影响蜥蜴的运动能力和体温调节.为检验断尾对蜥蜴运动能力和选择体温的影响,于2006年5月选取黑龙江省小兴安岭地区的一个胎生蜥蜴种群进行实验.结果表明:在30 ℃和24℃两个实验温度下,断尾后胎生蜥蜴的运动能力均明显下降,表现在停顿次数增多、最大可持续距离和最大疾跑速度减少等方面;断尾、温度和性别对胎生蜥蝎运动能力的影响在一定程度上是相互独立的,断尾是影响胎生蜥蜴运动能力的主要因素;断尾对胎生蜥蝎的选择体温没有显著影响.%Tail autotomy is an effective anti-predator strategy adopted by many lizards, but can induce the decrease of their body mass and the changes in their energy balance, giving effects on their locomotor ability and body temperature adjustment. In this paper, a common lizard {Lacerta vivipara) population was collected from Xiaoxing' an Mountains in Heilongjiang Province of Northeast China in May 2006 to examine the effects of tail loss on the L. Vivipara locomotor ability and selected body temperature. At experimental temperature 30 °C and 24 °C, the tail loss of L. Vivipara resulted in an obvious reduction in its locomotor performances. More specifically, the frequency of stopping locomotion increased whereas the maximum distance of continuous locomotion and the sprint speed decreased. To some extent, the effects of tail loss, experimental temperature , and sex on the locomotor ability of L. Vivipara were independently. Tail loss was the main factor affecting the locomotor ability, but had little effects on the selected body temperature.

  1. Pharmacokinetic characterization of mangosteen (Garcinia mangostana) fruit extract standardized to α-mangostin in C57BL/6 mice.

    Science.gov (United States)

    Petiwala, Sakina M; Li, Gongbo; Ramaiya, Atulkumar; Kumar, Anoop; Gill, Ravinder K; Saksena, Seema; Johnson, Jeremy J

    2014-04-01

    Previously, we have reported the pharmacokinetic (PK) properties of α-mangostin in mice. For this study, we evaluated the PK profile of α-mangostin using a standardized mangosteen extract in C57BL/6 mice. The primary objective was to determine the PK properties of α-mangostin when administered as an extract. This experiment was designed to test our primary hypothesis that α-mangostin in an extract should achieve a desirable PK profile. This is especially relevant as dietary supplements of mangosteen fruit are regularly standardized to α-mangostin. Mice received 100 mg/kg of mangosteen fruit extract orally, equivalent to 36 mg/kg of α-mangostin, and plasma samples were analyzed over a 24-hour period. Concentrations of α-mangostin were determined by liquid chromatography-tandem mass spectrometry. In addition, we evaluated the stability in the presence of phase I and phase II enzymes in liver and gastrointestinal microsomes. Furthermore, we identified evidence of phase II metabolism of α-mangostin. Further research will be required to determine if less abundant xanthones present in the mangosteen may modulate the PK parameters of α-mangostin.

  2. THE COCHlEAR RIBBON SYNAPTIC RESPONSE TO AMINOGIYCOSIDE OTOTOXICITY IN C57BL/6J MICE

    Institute of Scientific and Technical Information of China (English)

    LIU Ke; ZHAO Ning; SHI Chuang; WU Nan; LIU Huizhan; ZHANG Yue; YANG Weiyan; YANG Shiming

    2014-01-01

    Objective To investigate the early change of cochlear ribbon synapses on inner hair cells in response to aminoglycoside ototoxicity. Methods C57BL/6J mice received intraperitoneal injection of gentamicin (100 mg/kg/day), and the apical coil organ of Corti was examined on the 4th, 7th and 10th day (n=10). Litter-mates without gentamicin treatment served as controls (n=10). RIBEYE on the presynaptic membrane and AMPA receptors on the postsynaptic membrane were labeled with CtBP2 or GluR2/3 respectively. Three di-mension reconstruction was conducted using the 3DS MAX 8.0 software. Results There were no disruptions of outer or inner hair cells in all groups. However, the number of ribbon synapses on cochlear inner hair cells increased significantly within 7 days after gentamicin exposure (P<0.01), followed by a significant de-crease after 7 days.Conclusion During the early stage of aminoglycoside ototoxicity, increased population of cochlear ribbon synapses may indicate a significant down-regulation of synaptic function.

  3. Mono-jet, -photon and -Z Signals of a Supersymmetric (B-L) model at the Large Hadron Collider

    CERN Document Server

    Abdallah, W; Khalil, S; Moretti, S

    2015-01-01

    Search for invisible final states produced at the Large Hadron Collider (LHC) by new physics scenarios are normally carried out resorting to a variety of probes emerging from the initial state, in the form of single-jet, -photon and -$Z$ boson signatures. These are particularly effective for models of Supersymmetry (SUSY) in presence of $R$-parity conservation, owing to the presence in their spectra of a stable neutralino as dark matter candidate. We assume here as theoretical framework Supersymmetric ($B-L$) extension of the Standard Model (BLSSM), wherein a mediator for invisible decays can be $Z'$ boson. The peculiarity of the signal is thus that the final state objects carry a very large (transverse) missing energy, since the $Z'$ is naturally massive and constrained by direct searches and electro-weak precision tests to be at least in TeV scale region. Under these circumstances the efficiency in accessing the invisible final state and rejecting the standard model background is very high. This somehow com...

  4. Detection of Exceptional X-Ray Spectral Variability in the TeV BL Lac 1ES 2344+514

    CERN Document Server

    Giommi, P; Perlman, E S

    1999-01-01

    We present the results of six BeppoSAX observations of 1ES 2344+514, five of which were taken within a week. 1ES 2344+514, one of the few known TeV BL Lac objects, was detected by the BeppoSAX Narrow Field Instruments between 0.1 to large amplitude luminosity variability, associated with spectacular spectral changes, particularly when compared to the last observation when the source was found to be several times fainter, with a much steeper X-ray spectrum. The energy dependent shape of the lightcurve and the spectral changes imply a large shift (factor of 30 or more in frequency) of the peak of the synchrotron emission. At maximum flux the peak was located at or above 10 keV, making 1ES 2344+514 the second blazar (after MKN501) with the synchrotron peak in the hard X-ray band. The shift, and the corresponding increase in luminosity, might be due to the onset of a second synchrotron component extending from the soft to the hard X-ray band where most of the power is emitted. Rapid variability on a timescale of ...

  5. Genetic variation of carotenoids in Chinese bread wheat cultivars and the effect of the 1BL.1RS translocation

    Directory of Open Access Journals (Sweden)

    Wenshuang LI,Shengnan ZHAI,Hui JIN,Weie WEN,Jindong LIU,Xianchun XIA,Zhonghu HE

    2016-06-01

    Full Text Available Carotenoid content of wheat is an important criterion for prediction of the commercial and nutritional value of products made from bread wheat (Triticum aestivum cultivars. The objective of this study was to determine the major components of carotenoids in Chinese wheat using ultra performance liquid chromatography (UPLC including lutein, zeaxanthin, α-carotene and β-carotene. Grain carotenoid content was investigated in 217 cultivars from three major Chinese wheat regions and from seven other countries grown in two environments. Genotype contributed to the majority of variation in carotenoid components. Lutein, zeaxanthin and β-carotene concentrations varied from 18.3 to 100.1, 4.9 to 12.0 and 0.9 to 48.7 μg per 100 g in wheat flour with an average of 40.2, 7.2 and 18.2 μg per 100 g, respectively. Lutein (61.3% was the main carotenoid component, followed by β-carotene (27.7% and zeaxanthin (11.0%. No α-carotene was detected. Total carotenoids, lutein, zeaxanthin and β-carotene were all higher in cultivars with the 1BL.1RS translocation compared to those without the translocation. This is the first report on assay of lutein, zeaxanthin and β-carotene concentrations for a large number of wheat cultivars. These data will be useful for genetic improvement of wheat carotenoid content and for understanding of the carotenoid biosynthetic pathway in wheat.

  6. Inhibition of Aloperine on Dextran Sulphate Sodium-induced Chronic Colitis in C57BL/6 Mice

    Institute of Scientific and Technical Information of China (English)

    SONG Li-jun; ZHAO Wen-chang; DENG Hong-zhu

    2012-01-01

    Objective To investigate the effects of aloperine (ALO) on a model of dextran sulphate sodium (DSS)-induced chronic colitis in C57BL/6 mice.Methods Repeated colitis was induced by administration of four cycles of 4% DSS.The severity of colitis was assessed on the basis of clinical signs,ratio of colon weight and colon length,and histological grading scores.Moreover,secretory immunoglobulin A (S-IgA) and plasma haptoglobin (HP) were analyzed by enzyme-linked immunosorbent assay,and the changes of mRNA expression of ICAM-1and MIF gene in colorectal tissue were detected by quantitative reverse transcriptase real-time polymerase chain reaction using SYBR Green Ⅰ.Results ALO administration significantly attenuated the colon damage,caused substantial reductions of the rise in HP,and maintained the level of cecum S-IgA.ALO inhibited the ICAM-1mRNA expression and had no effect on MIF mRNA expression.Conclusion The effect of ALO on DSS-induced chronic colitis in mice is investigated for the first time,which suggests that ALO could be an attractive therapeutic candidate in the treatment of inflammatory bowel disease.

  7. Hypolipidemic action of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Micheli Stéfani Zarzecki

    2014-01-01

    Full Text Available Chrysin (5,7-dihydroxyflavone is a flavonoid, natural component of traditional medicinal herbs, present in honey, propolis and many plant extracts. The objective of this study was to investigate the hypolipidemic properties of chrysin on Triton WR-1339-induced hyperlipidemia in female C57BL/6 mice. Triton WR-1339 was administered intraperitoneally (400 mg/kg to overnight-fasted mice to develop acute hyperlipidemia. Chrysin was administered orally (10 mg/kg 30 min before Triton WR-1339. At 24 h after Triton WR-1339 injection, blood samples were collected to measure plasma lipid levels. The hepatic thiobarbituric acid reactive substances (TBARS, carbonyl content, non-protein sulfhydryl (NPSH and ascorbic acid (AA levels, as well as catalase (CAT and superoxide dismutase (SOD activity were recorded. Chrysin administration significantly decreased total cholesterol levels. In addition, it partially decreased non-high density lipoprotein-cholesterol and triglycerides levels in plasma of hyperlipidaemic mice. In addition chrysin administration prevented the increase on TBARS levels and prevented the decrease in SOD activity induced by Triton WR-1339. These findings indicated that chrysin was able to decrease plasma lipids concentration and that its antioxidant properties was, at least in part, involved in the hypolipidaemic action of chrysin.

  8. Pre-clinical evolutionary study of Clerodendrum phlomidis as an anti-obesity agent against high fat diet induced C57BL/6J mice

    Institute of Scientific and Technical Information of China (English)

    Vijay R Chidrawar; Krishnakant N Patel; Havagiray R Chitme; Shruti S Shiromwar

    2012-01-01

    Objective: Anti-obesity activity of alcoholic and methanolic extracts of roots of Clerodendrumphlomidis was evaluated against high fat diet (HFD) induced obesity in C57BL/6J female mice. Methods: Obesity was induced by feeding high fat diet for 13 weeks to C57BL/6J female mice and one group was kept on normal chow diet in order to evaluate the effect of Clerodendrumphlomidis on food intake, body weight changes, digestive enzyme activity, lipid metabolism, theromogenesis, adiposities diameter and histology of fat pad. Results: Among these two extracts methanolic extract of Clerodendrum phlomidis (MECP) have shown strong anti-obesity effect compare to alcoholic extract of Clerodendrum phlomidis (AECP). LD50 value was found to be more than 2000 mg/kg. Conclusions: MECP have shown more promising effects than AECP may be because of its multiple mechanisms. Anti-obesity activity produced by MECP is because of inhibition of pancreatic lipase activity which delays the intestinal absorption of dietary fat. Inhibition of pancreatic lipase activity was confirmed by in-vitro studies. MECP also containsβ-sitosterol in abundant amount which was confirmed by HPTLC analysis. Moreover flavonoid content in the plant has anorexic property. By this study we concluded that MECP is beneficial for the suppression of obesity and associated complications like T2DM.

  9. Programs as Data Objects

    DEFF Research Database (Denmark)

    This book constitutes the refereed proceedings of the Second Symposium on Programs as Data Objects, PADO 2001, held in Aarhus, Denmark, in May 2001. The 14 revised full papers presented were carefully reviewed and selected from 30 submissions. Various aspects of looking at programs as data objects...... are covered from the point of view of program analysis, program transformation, computational complexity, etc....

  10. On Objects and Events

    DEFF Research Database (Denmark)

    Eugster, Patrick Thomas; Guerraoui, Rachid; Damm, Christian Heide

    2001-01-01

    This paper presents linguistic primitives for publish/subscribe programming using events and objects. We integrate our primitives into a strongly typed object-oriented language through four mechanisms: (1) serialization, (2) multiple sub typing, (3) closures, and (4) deferred code evaluation. We...

  11. Choosing for learning objects

    NARCIS (Netherlands)

    Schoonenboom, Judith; Emans, Bruno; Meijer, Joost

    2006-01-01

    Choosing for learning objects discusses eight educational ambitions and the possible roles of learning objects in realising these ambitions. The eight educational ambitions are: (1) Creating independent learning pathways, for example for lifelong learners; (2) Making education more flexible; (3) Res

  12. Conscience and Conscientious Objections

    NARCIS (Netherlands)

    Schinkel, Anders

    2007-01-01

    In Western countries conscientious objection is usually accommodated in various ways, at least in certain areas (military conscription, medicine) and to some extent. It appears to be regarded as fundamentally different from other kinds of objection. But why? This study argues that conscientious obje

  13. Superlensing Microscope Objective Lens

    CERN Document Server

    Yan, Bing; Parker, Alan; Lai, Yukun; Thomas, John; Yue, Liyang; Monks, James

    2016-01-01

    Conventional microscope objective lenses are diffraction limited, which means that they cannot resolve features smaller than half the illumination wavelength. Under white light illumination, such resolution limit is about 250-300 nm for an ordinary microscope. In this paper, we demonstrate a new superlensing objective lens which has a resolution of about 100 nm, offering at least two times resolution improvement over conventional objectives in resolution. This is achieved by integrating a conventional microscope objective lens with a superlensing microsphere lens using a 3D printed lens adaptor. The new objective lens was used for label-free super-resolution imaging of 100 nm-sized engineering and biological samples, including a Blu-ray disc sample, semiconductor chip and adenoviruses. Our work creates a solid base for developing a commercially-viable superlens prototype, which has potential to transform the field of optical microscopy and imaging.

  14. Cultivating objects in interaction

    DEFF Research Database (Denmark)

    Hazel, Spencer

    2014-01-01

    is chapter explores patterns of repeated orientations to physical objects in interactants’ visuo-spatial and haptic surround. A number of examples are presented from advice-giving activities in various institutional settings, where participants-in-interaction initially draw on material objects...... at hand while pursuing a particular line of explanation, and then return to these objects at later intervals. e analysis suggests that the objects are afforded representational properties through their being anchored to some referent in the talk, and that participants subsequently draw...... on these associations for describing, disambiguating or clarifying aspects of the relatively complex procedural frameworks discussed in the settings. is suggests that the temporal stability of material objects available to participants makes them an ideal resource to be developed as visual motifs....

  15. Hardware Objects for Java

    DEFF Research Database (Denmark)

    Schoeberl, Martin; Thalinger, Christian; Korsholm, Stephan

    2008-01-01

    Java, as a safe and platform independent language, avoids access to low-level I/O devices or direct memory access. In standard Java, low-level I/O it not a concern; it is handled by the operating system. However, in the embedded domain resources are scarce and a Java virtual machine (JVM) without...... an underlying middleware is an attractive architecture. When running the JVM on bare metal, we need access to I/O devices from Java; therefore we investigate a safe and efficient mechanism to represent I/O devices as first class Java objects, where device registers are represented by object fields. Access...... to those registers is safe as Java’s type system regulates it. The access is also fast as it is directly performed by the bytecodes getfield and putfield. Hardware objects thus provide an object-oriented abstraction of low-level hardware devices. As a proof of concept, we have implemented hardware objects...

  16. Beginning Objective-C

    CERN Document Server

    Dovey, James

    2012-01-01

    Objective-C is today's fastest growing programming language, at least in part due to the popularity of Apple's Mac, iPhone and iPad. Beginning Objective-C is for you if you have some programming experience, but you're new to the Objective-C programming language and you want a modern-and fast-way forwards to your own coding projects. Beginning Objective-C offers you a modern programmer's perspective on Objective-C courtesy of two of the best iOS and Mac developers in the field today, and gets you programming to the best of your ability in this important language.  It gets you rolling fast into

  17. Kuiper Binary Object Formation

    CERN Document Server

    Nazzario, R C; Covington, C; Kagan, D; Hyde, T W

    2005-01-01

    It has been observed that binary Kuiper Belt Objects (KBOs) exist contrary to theoretical expectations. Their creation presents problems to most current models. However, the inclusion of a third body (for example, one of the outer planets) may provide the conditions necessary for the formation of these objects. The presence of a third massive body not only helps to clear the primordial Kuiper Belt but can also result in long lived binary Kuiper belt objects. The gravitational interaction between the KBOs and the third body causes one of four effects; scattering into the Oort cloud, collisions with the growing protoplanets, formation of binary pairs, or creation of a single Kuiper belt object. Additionally, the initial location of the progenitors of the Kuiper belt objects also has a significant effect on binary formation.

  18. The ultrastructure of cochlear afferent synapse of inner hair cells in C57BL/6J mice%C57BL/6J小鼠耳蜗内毛细胞传入神经突触的超微结构观察

    Institute of Scientific and Technical Information of China (English)

    施磊; 柳柯; 赵宁; 魏宏权; 刘红娟; 姜学钧

    2011-01-01

    目的 利用投射电镜观察C57Bl/6J小鼠耳蜗内毛细胞传人神经突触的形态和结构.方法 选择发育成熟的C57Bl/6J小鼠,ABR检测听力正常后获取耳蜗标本,分别经过半薄定位和超薄连续切片观察的方法寻找观察耳蜗内毛细胞传入神经突触的形态和结构,探讨发育成熟状态下小鼠耳蜗内毛细胞突触的形态和结构特点,并进一步分析它们可能出现的区域以及与周围解剖结构的关系.结果 在听力正常的C57Bl/6J小鼠的不同耳蜗内毛细胞核下区域可以观察到带状突触结构,包括ribbon、突触囊泡、突触间隙和突触后致密带等典型结构;然而有时即使是在听力正常的小鼠耳蜗内,也不能同时观察到这些结构的伞部,即内毛细胞带状突触的超微结构和形态可能表现出彼此之间存在明显区别的形式.结论 在听力正常的生理状态下,成熟小鼠(e57BL/6J)耳蜗内毛细胞突触的形态和结构处于动态变化之中,突触的个体形态和结构可以表现出不同的特点,而这种结构上的动态变化可能和突触功能的变化有关.%Objective To study the ultrastmctue of afferent synapse of inner hair cells ( IHCs ) in C57BL/6J mice. Method The adult c57BL/6J mice with normal hearing function were selected, and the cochleas were taken out and the semi and ultra sections were performed for the ultrastructural observation by transmission electron microscope(TEM). The ultrastructural properties within afferent synapses as well as structures nearby were analysized, and the potential correlation between the afferent synapses and other structures around was explored. Result The typical afferent synapse structure was observed including the presynaptic ribbon, synapse vesicles, the clear synapse cleft and the postsynaptic density(PSD) in mice with normal hearing ability. However, sometimes, those synaptic components could not be captured by TEM observation even in same cochlear section

  19. Tracking of deformable objects

    Science.gov (United States)

    Aswani, Parimal; Wong, K. K.; Chong, Man N.

    2000-12-01

    Tracking of moving-objects in image sequences is needed for several video processing applications such as content-based coding, object oriented compression, object recognition and more recently for video object plane extraction in MPEG-4 coding. Tracking is a natural follow-up of motion-based segmentation. It is a fast and efficient method to achieve coherent motion segments along the temporal axis. Segmenting out moving objects for each and every frame in a video sequence is a computationally expensive approach. Thus, for better performance, semi-automatic segmentation is an acceptable compromise as automatic segmentation approaches rely heavily on prior assumptions. In semi-automatic segmentation approaches, motion-segmentation is performed only on the initial frame and the moving object is tracked in subsequent frames using tracking algorithms. In this paper, a new model for object tracking is proposed, where the image features -- edges, intensity pattern, object motion and initial keyed-in contour (by the user) form the prior and likelihood model of a Markov Random Field (MRF) model. Iterated Conditional Mode (ICM) is used for the minimization of the global energy for the MRF model. The motion segment for each frame is initialized using the segment information from the previous frame. For the initial frame, the motion segment is obtained by manually keying in the object contour. The motion-segments obtained using the proposed model are coherent and accurate. Experimental results on tracking using the proposed algorithm for different sequences -- Bream, Alexis and Claire are presented in this paper. The results obtained are accurate and can be used for a variety of applications including MPEG-4 Video Object Plane (VOP) extraction.

  20. Crystal Structure of Crataeva tapia Bark Protein (CrataBL and Its Effect in Human Prostate Cancer Cell Lines.

    Directory of Open Access Journals (Sweden)

    Rodrigo da Silva Ferreira

    Full Text Available A protein isolated from the bark of Crataeva tapia (CrataBL is both a Kunitz-type plant protease inhibitor and a lectin. We have determined the amino acid sequence and three-dimensional structure of CrataBL, as well as characterized its selected biochemical and biological properties. We found two different isoforms of CrataBL isolated from the original source, differing in positions 31 (Pro/Leu; 92 (Ser/Leu; 93 (Ile/Thr; 95 (Arg/Gly and 97 (Leu/Ser. CrataBL showed relatively weak inhibitory activity against trypsin (Kiapp = 43 µM and was more potent against Factor Xa (Kiapp = 8.6 µM, but was not active against a number of other proteases. We have confirmed that CrataBL contains two glycosylation sites and forms a dimer at high concentration. The high-resolution crystal structures of two different crystal forms of isoform II verified the β-trefoil fold of CrataBL and have shown the presence of dimers consisting of two almost identical molecules making extensive contacts (∼645 Å(2. The structure differs from those of the most closely related proteins by the lack of the N-terminal β-hairpin. In experiments aimed at investigating the biological properties of CrataBL, we have shown that addition of 40 µM of the protein for 48 h caused maximum growth inhibition in MTT assay (47% of DU145 cells and 43% of PC3 cells. The apoptosis of DU145 and PC3 cell lines was confirmed by flow cytometry using Annexin V/FITC and propidium iodide staining. Treatment with CrataBL resulted in the release of mitochondrial cytochrome c and in the activation of caspase-3 in DU145 and PC3 cells.

  1. Identification of riboflavin: revealing different metabolic characteristics between Escherichia coli BL21(DE3) and MG1655.

    Science.gov (United States)

    Wang, Xinran; Wang, Qian; Qi, Qingsheng

    2015-06-01

    There are many physiological differences between Escherichia coli B and K-12 strains, owing to their different origins. Deeper insight into the metabolic and regulative mechanisms of these strains will inform improved usage of these industrial workhorses. In the present study, we observed that BL21 fermentation broth gradually turned yellow during cultivation. By spectral analysis and liquid chromatography-mass spectrometry identification, we confirmed for the first time that the yellow substance accumulated in the fermentation broth is riboflavin. Comparing the enzyme sequences involved in riboflavin metabolism between BL21 and MG1655, we identified a site mutation on the 115 residue of bifunctional riboflavin kinase/FMN adenylyltransferase (RibF) in BL21. This His115Leu mutation was found to reduce enzyme activity to 55% of that of MG1655, which is probably one reason for riboflavin accumulation in BL21. Quantitative PCR analysis showed that genes of the entire branch of the riboflavin and FAD biosynthesis pathways in BL21 were up-regulated. Several physiological and metabolic characteristics of BL21 and MG1655 were found to be different, and may also be related to the riboflavin accumulation.

  2. NLO+NLL Collider Bounds, Dirac Fermion and Scalar Dark Matter in the B-L Model

    CERN Document Server

    Klasen, Michael; Queiroz, Farinaldo S

    2016-01-01

    Baryon and lepton numbers being accidental global symmetries of the Standard Model (SM), it is natural to promote them to local symmetries. However, to preserve anomaly freedom, only combinations of B-L are viable. In this spirit, we investigate possible dark matter realizations in the context of the $U(1)_{B-L}$ model: (i) Dirac fermion with unbroken B-L; (ii) Dirac fermion with broken B-L; (iii) scalar dark matter; (iv) two component dark matter. We compute the relic abundance, direct and indirect detection observables and confront them with recent results from Planck, LUX-2016, and Fermi-LAT and prospects from XENON1T. In addition to the well known LEP bound $M_{Z^{\\prime}}/g_{BL} \\gtrsim 7$ TeV, we include often ignored LHC bounds using 13 TeV dilepton (dimuon+dielectron) data at next-to-leading order plus next-to-leading logarithmic accuracy. We show that, for gauge couplings smaller than $0.4$, the LHC gives rise to the strongest collider limit. In particular, we find $M_{Z^{\\prime}}/g_{BL} > 8.7$ TeV f...

  3. Two Interesting Southern Objects

    Science.gov (United States)

    Gyulbudaghian, A. L.

    2016-06-01

    Two southern objects are studied. The first, the planetary nebula PK 349-01.1, is of interest because it has a chain of jets ejected from the central star. 12C(1-0) observations of the vicinity of this object reveal red- and blue-shifted molecular outflows. The second object is a star formation region consisting of two groups of IR stars. These groups have a trapezium-like configuration. Two stars in one of these groups are associated with a ring-shaped nebulae. This star formation region is associated with a new radial system of dark globules.

  4. Cultivating objects in interaction

    DEFF Research Database (Denmark)

    Hazel, Spencer

    2014-01-01

    is chapter explores patterns of repeated orientations to physical objects in interactants’ visuo-spatial and haptic surround. A number of examples are presented from advice-giving activities in various institutional settings, where participants-in-interaction initially draw on material objects...... on these associations for describing, disambiguating or clarifying aspects of the relatively complex procedural frameworks discussed in the settings. is suggests that the temporal stability of material objects available to participants makes them an ideal resource to be developed as visual motifs....

  5. C57 BL/6J小鼠听力及耳蜗毛细胞活性的年龄相关性研究%Study of the Correction between the Age Related Hearing Loss and the Cytoactivity Factors of the Cochlear Hair Cell in C57BL/6J Mice

    Institute of Scientific and Technical Information of China (English)

    周良强; 吴绍苓; 王燕; 褚汉启; 崔永华

    2009-01-01

    Objective To establish the mice model of AHL, to investigate the relationship between AHL and the cytoactive factors of the cochlear hair cells in C57BL/6J mice, and to classify the presbycusis models of the C57BL/6J mice. Methods C57BL/6J mice were divided into 6 experimental groups by age (A: 3 months old(m), B: 8 m, C: 9 m, D: 10 m, F: 17 m, G: 18 m) . The auditory functions mice were measured by auditory brainstem response (ABR) with the stimulus click and toneburst at 6 kHz and 8 kHz. 3 months later, Groups C , G, E and H were tested again for ABR. After ABR testing, the cytoactive of the hair cells was detected by succinate dehydrogenase staining and surface preparation technique(two mice from each group except groups C and G). Results The ABR thresholds elevated with age, and the marked change of the cochlea was the degeneration of the cytoactive of the cochlear hair cells, especially those of the outer hair cells. In the beginning, the basement of the basal membrane suffered from the mitochondrion degeneration in the outer hair cells, then it spread to the top region. Subsequently, the inner hair cells were involved. Conclusion C57BL/6J mouse was a typical animal model for the AHL,and the main change of the cochlea was the degeneration of the hair cells, especially the outer hair cells. Thus, C57BL/6J mice can be used as a suitable animal model for the study of presbycusis.%目的 建立年龄相关性听力损失(age-related hearing loss,AHL)的小鼠动物模型,探讨C57BL/6J小鼠发生AHL与毛细胞活性变化的关系,并初步对C57BL/6J小鼠AHL模型进行AHL的病理分类.方法 按3、8、9、10、17、18月龄段分6组培育C57BL/6J小鼠,各组分别进行听性脑干反应(ABR)测试,对耳蜗毛细胞行琥珀酸脱氢酶染色并作基底膜硬铺片,观察各年龄段小鼠内外毛细胞线粒体琥珀酸脱氢酶的活性.结果 C57BL/6J小鼠随年龄增大,ABR阈值明显增高,在3月龄到9月龄期间ABR平均反应阈值增大

  6. Piles of objects

    KAUST Repository

    Hsu, Shu-Wei

    2010-01-01

    We present a method for directly modeling piles of objects in multi-body simulations. Piles of objects represent some of the more interesting, but also most time-consuming portion of simulation. We propose a method for reducing computation in many of these situations by explicitly modeling the piles that the objects may form into. By modeling pile behavior rather than the behavior of all individual objects, we can achieve realistic results in less time, and without directly modeling the frictional component that leads to desired pile shapes. Our method is simple to implement and can be easily integrated with existing rigid body simulations. We observe notable speedups in several rigid body examples, and generate a wider variety of piled structures than possible with strict impulse-based simulation. © 2010 ACM.

  7. Safety objectives for 2014

    CERN Multimedia

    HSE Unit

    2014-01-01

    This is the third year in which the CERN Management has presented annual safety objectives for the Organization, the “HSE Objectives”.   The HSE objectives for 2014, which were announced by the Director-General at his traditional New Year’s address to the staff and were presented at the first Enlarged Directorate meeting of the year, have been drawn up and agreed in close collaboration between the DSOs, the HSE Unit and the DG himself. From safety in the workplace to radiation and environmental protection, the document emphasises that “Safety is a priority for CERN” and that safety policy is a key element in how the Organization is run. And, like all policies, it generates objectives that “serve as a general framework for action”. The HSE objectives are broken down into the following fields: occupational health and safety on sites and in the workplace, radiation protection, radiation safety, environmental protection, emerge...

  8. This elusive objective existence

    CERN Document Server

    Mohrhoff, U

    2004-01-01

    Zurek's existential interpretation of quantum mechanics suffers from three classical prejudices, including the belief that space and time are intrinsically and infinitely differentiated. They compel him to relativize the concept of objective existence in two ways. The elimination of these prejudices makes it possible to recognize the quantum formalism's ontological implications - the relative and contingent reality of spatiotemporal distinctions and the extrinsic and finite spatiotemporal differentiation of the physical world - which in turn makes it possible to arrive at an unqualified objective existence. Contrary to a widespread misconception, viewing the quantum formalism as being fundamentally a probability algorithm does not imply that quantum mechanics is concerned with states of knowledge rather than states of Nature. On the contrary, it makes possible a complete and strongly objective description of the physical world that requires no reference to observers. What objectively exists, in a sense that r...

  9. Protected Objects in Java

    DEFF Research Database (Denmark)

    Løvengreen, Hans Henrik; Schwarzer, Jens Christian

    1998-01-01

    We present an implementation of Ada 95's notion of protected objects in Java. The implementation comprises a class library supporting entry queues and a (pre-) compiler translating slightly decorated Java classes to pure Java classes utilizing the library.......We present an implementation of Ada 95's notion of protected objects in Java. The implementation comprises a class library supporting entry queues and a (pre-) compiler translating slightly decorated Java classes to pure Java classes utilizing the library....

  10. Choosing for learning objects

    OpenAIRE

    Schoonenboom, Judith; Emans, Bruno; Meijer, Joost

    2006-01-01

    Choosing for learning objects discusses eight educational ambitions and the possible roles of learning objects in realising these ambitions. The eight educational ambitions are: (1) Creating independent learning pathways, for example for lifelong learners; (2) Making education more flexible; (3) Responding to differences between students; (4) The joint development of learning materials together with other institutions or external parties; (5) Attuning to professional practice; (6) Attuning to...

  11. Objects of consciousness.

    Science.gov (United States)

    Hoffman, Donald D; Prakash, Chetan

    2014-01-01

    Current models of visual perception typically assume that human vision estimates true properties of physical objects, properties that exist even if unperceived. However, recent studies of perceptual evolution, using evolutionary games and genetic algorithms, reveal that natural selection often drives true perceptions to extinction when they compete with perceptions tuned to fitness rather than truth: Perception guides adaptive behavior; it does not estimate a preexisting physical truth. Moreover, shifting from evolutionary biology to quantum physics, there is reason to disbelieve in preexisting physical truths: Certain interpretations of quantum theory deny that dynamical properties of physical objects have definite values when unobserved. In some of these interpretations the observer is fundamental, and wave functions are compendia of subjective probabilities, not preexisting elements of physical reality. These two considerations, from evolutionary biology and quantum physics, suggest that current models of object perception require fundamental reformulation. Here we begin such a reformulation, starting with a formal model of consciousness that we call a "conscious agent." We develop the dynamics of interacting conscious agents, and study how the perception of objects and space-time can emerge from such dynamics. We show that one particular object, the quantum free particle, has a wave function that is identical in form to the harmonic functions that characterize the asymptotic dynamics of conscious agents; particles are vibrations not of strings but of interacting conscious agents. This allows us to reinterpret physical properties such as position, momentum, and energy as properties of interacting conscious agents, rather than as preexisting physical truths. We sketch how this approach might extend to the perception of relativistic quantum objects, and to classical objects of macroscopic scale.

  12. Correlation between -Ray and Radio Bands for -Ray Loud Blazars

    Indian Academy of Sciences (India)

    D. X. Wu; J. H. Fan; S. H. Li

    2014-09-01

    The most identified sources observed by Fermi are blazars (Flat Spectrum Radio Quasars (FSRQs) and BL Lacertae objects (BLs). In this paper, we obtained 124 -ray loud blazars with available -ray and radio (core and total) data. It is interesting that the -ray luminosity have a good correlation with the radio luminosity. This phenomenon exists in the core radio luminosity (c) and total radio luminosity (t). The correlation between the -ray and the radio luminosities is still stronger even after we eliminated the redshift effect, which suggests that the -ray radiations in the -ray loud blazars are strongly beamed.

  13. A statistical classification of the unassociated gamma-ray sources in the second Fermi Large Area Telescope Catalog

    Institute of Scientific and Technical Information of China (English)

    Zhu Mao; Yun-Wei Yu

    2013-01-01

    With the assistance of the identified/associated sources in the second Fermi Large Area Telescope (LAT) catalog,we analyze and resolve the spatial distribution and the distributions of the gamma-ray spectral and variability indices of the remaining 575 unassociated Fermi LAT sources.Consequently,it is suggested that the unassociated sources could statistically consist of Galactic supernova remnants/pulsar wind nebulae,BL Lacertae objects,flat spectrum radio quasars and other types of active galaxies with fractions of 25%,29%,41% and 5 %,respectively.

  14. Multiwavelength study of quiescent states of MRK 421 with unprecedented hard x-ray coverage provided by NuSTAR in 2013

    DEFF Research Database (Denmark)

    Baloković, M.; Paneque, D.; Madejski, G.;

    2016-01-01

    We present coordinated multiwavelength observations of the bright, nearby BL Lacertae object Mrk 421 taken in 2013 January-March, involving GASP-WEBT, Swift, NuSTAR, Fermi-LAT, MAGIC, VERITAS, and other collaborations and instruments, providing data from radio to very high energy (VHE) γ-ray band...... in the NuSTAR light curves point toward in situ electron acceleration and suggest that there are multiple compact regions contributing to the broadband emission of Mrk 421 during low-activity states....

  15. Effect of Fenbendazole on Three Behavioral Tests in Male C57BL/6N Mice

    OpenAIRE

    Bharathi S. Gadad; Daher, João P.L.; Hutchinson, Eric K; Brayton, Cory F.; Dawson, Ted M.; Pletnikov, Mikhail V.; Watson, Julie

    2010-01-01

    Pinworms are highly contagious parasites of laboratory rodents that often are treated with fenbendazole. To our knowledge, the effect of fenbendazole at therapeutic dosages on behavioral tests in mice has not been evaluated. Here we studied 6-wk-old male C57BL/6N mice. We compared the behavior of control mice (fed regular diet) with 3 groups of mice treated with dietary fenbendazole. Treatment groups were 4 wk of fenbendazole, 2 wk of fenbendazole followed by 2 wk of regular diet, and 2 wk of...

  16. Transcriptional profiling of thymidine-producing strain recombineered from Escherichia coli BL21

    Directory of Open Access Journals (Sweden)

    Jin-Sook Kim

    2015-12-01

    Full Text Available DNA microarrays were used to compare the expression profiles of a thymidine overproducing strain (BLT013 and its isogenic parent, Escherichia coli BL21(DE3, when each was grown under well-defined thymidine production conditions with glycerol as carbon source. Here we describe the experimental procedures and methods in detail to reproduce the results and provide resource to be applied to similar engineering approach (available at Gene Expression Omnibus database under GSE69963. Taken together, the microarray data provide a basis for new testable hypotheses regarding enhancement of thymidine productivity and attaining a more complete understanding of nucleotide metabolism in bacteria.

  17. 抽象派代表 LG BL40 New Chocolate

    Institute of Scientific and Technical Information of China (English)

    2009-01-01

    2 朦胧的艺术气质、抽象的设计风格、国标化的设计理念.当这些词汇一起出现在同一款手机上时.你会用什么表情来迎接它?是否也和我们一样满怀期待与好奇?是的,这就是LG在时隔三年后-即将推出的新版巧克力手机-BL40。

  18. 耽美小说中的厌女情结%Misogyny in BL Novels

    Institute of Scientific and Technical Information of China (English)

    闫文菲

    2015-01-01

    耽美小说虽然是关于男男同性爱恋的文学作品,但与同性恋文学又有着很明显的差异,它更多的是女性作者对男性同性恋爱情的自我想象和审美期待。女性作者在这种想象和期待中描绘了一种纯粹美好的感情状态。然而,在表达对纯爱追求的同时,女性作者却普遍表现出了强烈的厌女情结———被丑化的第三者,被简化的“女朋友”和被雄化的女英雄,这三类女性形象无一不表现着女性作者对女性的冷漠和厌恶。而造成这种厌女倾向的原因,除耽美小说自身的限制之外,最重要的就是男权文化对女性作者的浸淫。%BL novels are mainly about homosexual stories,but they are quite different from homosexual literature. These novels are largely written by female writers to put their own illusions and the aesthetic expectations on the ho-mosexual love.With the imagination and the expectation,they′re drawing a pure and beautiful love state.Howev-er,while in pursuit of a pure love,the female authors generally show a strong misogyny in the BL novels:either the defamed mistresses,or the simplified female friends,or the masculinized heroines,presenting indifference and an-tipathy to the female images in BL novels.The reason why the misogyny emerges is not only that the BL novels are immature,but more importantly is that the patriarchal culture has imposed a profound influence on the females,in-cluding these female writers.

  19. Sweetener preference of C57BL/6ByJ and 129P3/J mice

    OpenAIRE

    2001-01-01

    Previous studies have shown large differences in taste responses to several sweeteners between mice from the C57BL/6ByJ (B6) and 129P3/J (129) inbred strains. The goal of this study was to compare behavioral responses of the B6 and 129 mice to a wider variety of sweeteners. Seventeen sweeteners were tested using two-bottle preference tests with water. Three main patterns of strain differences were evident. First, sucrose, maltose, saccharin, acesulfame, sucralose and SC-45647 were preferred b...

  20. Increase of the seizure threshold in C57BL/6 mice after citicoline administration.

    Science.gov (United States)

    Karpova, M N; Zin'kovskii, K A; Kuznetsova, L V; Klishina, N V

    2015-01-01

    We studied the dose-dependent effect of preventive intraperitoneal injection of citicoline (cytidine 5'-diphosphocholine) on acute generalized epileptiform activity in C57Bl/6 mice. The duration of citicoline action was also evaluated. Administration of citicoline in doses of 500 and 1000 mg/kg 1 h before treatment with the convulsant agent pentylenetetrazole produced an anticonvulsant effect. This effect was manifested in an increase of the threshold of clonic seizures and tonic phase of seizures with lethal outcome. Moreover, the latency of seizure development was elevated under these conditions. The anticonvulsant effect of citicoline persisted for 6 h after its injection.

  1. Near Earth Objects

    DEFF Research Database (Denmark)

    Wolff, Stefan

    2006-01-01

    The word planet comes from Greek planetes, wanderers, because the planets appear to wander across the celestial sphere, contrary to the fixed stars. This thesis presents several methods for using this motion to distinguish between stars and solar system objects in order to detect and track NEOs......, Near Earth Objects: Asteroids and comets following paths that bring them near the Earth. NEOs have collided with the Earth since its formation, some causing local devastation, some causing global climate changes, yet the threat from a collision with a near Earth object has only recently been recognised...... and accepted. The European Space Agency mission Gaia is a proposed space observatory, designed to perform a highly accurate census of our galaxy, the Milky Way, and beyond. Through accurate measurement of star positions, Gaia is expected to discover thousands of extra-solar planets and follow the bending...

  2. Invariance and Objectivity

    Science.gov (United States)

    Vollmer, Gerhard

    2010-10-01

    Scientific knowledge should not only be true, it should be as objective as possible. It should refer to a reality independent of any subject. What can we use as a criterion of objectivity? Intersubjectivity (i.e., intersubjective understandability and intersubjective testability) is necessary, but not sufficient. Other criteria are: independence of reference system, independence of method, non-conventionality. Is there some common trait? Yes, there is: invariance under some specified transformations. Thus, we say: A proposition is objective only if its truth is invariant against a change in the conditions under which it was formulated. We give illustrations from geometry, perception, neurobiology, relativity theory, and quantum theory. Such an objectivist position has many advantages.

  3. [Medicine and conscientious objection].

    Science.gov (United States)

    Martínez, K

    2007-01-01

    Conscientious objection to democratically accepted laws in democratic societies is a fact, both among citizens and among professionals. Due respect for laws is a prima facie duty in these societies. But democratic justice must at the same time respect peoples' conscience for it constitutes the ethical identity of individuals. And both law and ethics are necessary - although neither of them is sufficient - for its realization. The problem of conscientious objection among healthcare professionals is analysed from this standpoint and the conclusion is that objection is not an absolute right to exemption from several duties, but that the responsibility of the professional and of the institutions towards the citizenry must always be taken into account. Some solutions are suggested that try to protect both the professionals and the citizens in a bi-directional way.

  4. Million object spectrograph

    Science.gov (United States)

    Ditto, Thomas D.; Ritter, Joseph M.

    2008-07-01

    A new class of astronomical telescope with a primary objective grating (POG) has been studied as an alternative to mirrors. Nineteenth century POG telescopes suffered from low resolution and ambiguity of overlapping spectra as well as background noise. The present design uses a conventional secondary spectrograph to disambiguate all objects while enjoying a very wide instantaneous field-of-view, up to 40°. The POG competes with mirrors, in part, because diffraction gratings provide the very chromatic dispersion that mirrors defeat. The resulting telescope deals effectively with long-standing restrictions on multiple object spectrographs (MOS). The combination of a POG operating in the first-order, coupled to a spectrographic astronomical telescope, isolates spectra from all objects in the free spectral range of the primary. First disclosed as a concept in year 2002, a physical proof-of-principle is now reported. The miniature laboratory model used a 50 mm plane grating primary and was able to disambiguate between objects appearing at angular resolutions of 55 arcseconds and spectral spacings of 0.15 nm. Astronomical performance is a matter of increasing instrument size. A POG configured according to our specifications has no moving parts during observations and is extensible to any length that can be held flat to tolerances approaching float glass. The resulting telescope could record over one million spectra per night of objects in a line of right ascension. The novel MOS does not require pre-imaging to start acquisition of uncharted star fields. Problems are anticipated in calibration and integration time. We propose means to ameliorate them.

  5. Objective Eulerian Coherent Structures

    CERN Document Server

    Serra, M

    2015-01-01

    We define objective Eulerian Coherent Structures (OECSs) in two-dimensional, non-autonomous dynamical systems as instantaneously most influential material curves. Specifically, OECSs are stationary curves of the averaged instantaneous material stretching-rate or material shearing-rate functionals. From these objective (frame-invariant) variational principles, we obtain explicit differential equations for hyperbolic, elliptic and parabolic OECSs. As illustration, we compute OECSs in an unsteady ocean velocity data set. In comparison to structures suggested by other common Eulerian diagnostic tools, we find OECSs to be the correct short-term cores of observed trajectory deformation patterns.

  6. Sound Objects for SVG

    OpenAIRE

    Colbrant, Audrey; Lasorsa, Yohan; Lemordant, Jacques; Liodenot, David; Razafimahazo, Mathieu

    2010-01-01

    International audience; A sound object can be defined as a time structure of audio chunks whose duration is on the time scale of 100 ms to several seconds. Sound objects have heterogeneous and time-varying properties. They are the basic elements of any format for Interactive Audio (IA). We have designed an XML language, A2ML, for Interactive Audio which offers, concerning the sequencing of sounds, a level of capabilities similar to that of iXMF, the interactive audio file format defined by th...

  7. Pinocchio: Geppetto's transitional object

    Directory of Open Access Journals (Sweden)

    Gabriele Zeloni

    2015-01-01

    Full Text Available The literature has been considered by Freud and others after him, a form of unaware exploration of mind that can leads to discoveries similar to psychoanalysis’s discoveries. From this perspective, the author puts forward the following hypothesis: Pinocchio is a puppet who comes to life and is therefore, from a child's perception, a transitional object according to Winnicott. Consequently Geppetto is nothing more than the involuntary representation of any child interacting with the transitional object. The author explains the results of the analysis of the text in support of the hypothesis and reflects on the impact of The adventure of Pinocchio on the reader.

  8. Learning Objects Web

    DEFF Research Database (Denmark)

    Blåbjerg, Niels Jørgen

    2005-01-01

    Learning Objects Web er et DEFF projekt som Aalborg Universitetsbibliotek har initieret. Projektet tager afsæt i de resultater og erfaringer som er opnået med vores tidligere projekt Streaming Webbased Information Modules (SWIM). Vi har et internationalt netværk af interessenter som giver os...... sparring og feedback i forhold til udviklingskoncept både omkring de teoretiske rammer og i forhold til praktisk anvendelse af vores undervisningskoncept. Med disse rygstød og input har vi forfulgt ønsket om at videreudvikle SWIM i det nye projekt Learning Objects Web. Udgivelsesdato: juni...

  9. Capturing Near Earth Objects

    OpenAIRE

    Baoyin, Hexi; CHEN Yang; Li, Junfeng

    2011-01-01

    Recently, Near Earth Objects (NEOs) have been attracting great attention, and thousands of NEOs have been found to date. This paper examines the NEOs' orbital dynamics using the framework of an accurate solar system model and a Sun-Earth-NEO three-body system when the NEOs are close to Earth to search for NEOs with low-energy orbits. It is possible for such an NEO to be temporarily captured by Earth; its orbit would thereby be changed and it would become an Earth-orbiting object after a small...

  10. The Road to Objects

    Directory of Open Access Journals (Sweden)

    Graham Harman

    2011-09-01

    Full Text Available Harman presents an outline of how object-oriented ontology (OOO differentiates itself from other branches of speculative realism. Can OOO steer philosophy from an epistemological project that tends to reduce the discipline to "a series of small-time drug busts"?

  11. The Road to Objects

    OpenAIRE

    Graham Harman

    2011-01-01

    Harman presents an outline of how object-oriented ontology (OOO) differentiates itself from other branches of speculative realism. Can OOO steer philosophy from an epistemological project that tends to reduce the discipline to "a series of small-time drug busts"?

  12. Big Java late objects

    CERN Document Server

    Horstmann, Cay S

    2012-01-01

    Big Java: Late Objects is a comprehensive introduction to Java and computer programming, which focuses on the principles of programming, software engineering, and effective learning. It is designed for a two-semester first course in programming for computer science students.

  13. Forecasters' Objectives and Strategies

    DEFF Research Database (Denmark)

    Marinovic, Iván; Ottaviani, Marco; Sørensen, Peter Norman

    2013-01-01

    This chapter develops a unified modeling framework for analyzing the strategic behavior of forecasters. The theoretical model encompasses reputational objectives, competition for the best accuracy, and bias. Also drawing from the extensive lit- erature on analysts, we review the empirical evidence...

  14. Common Object Library Description

    Science.gov (United States)

    2012-08-01

    Information Modeling ( BIM ) technology to be successful, it must be consistently applied across many projects, by many teams. The National Building Information ...distribution is unlimited. 13. SUPPLEMENTARY NOTES 14. ABSTRACT For Building Information Modeling ( BIM ) technology to be successful, it must be... BIM standards and for future research projects. 15. SUBJECT TERMS building information modeling ( BIM ), object

  15. The Language of Objects

    DEFF Research Database (Denmark)

    Eskildsen, Kasper Risbjerg

    2012-01-01

    . The arrangement of artifacts not only helped him formulate his theories, but also allowed him to present his arguments in a language of objects. At the same time, Thomsen's definition of archaeology as a museum science placed his branch of archaeology in a closer relationship with other museum sciences...

  16. Testing object Interactions

    NARCIS (Netherlands)

    Grüner, Andreas

    2010-01-01

    In this thesis we provide a unit testing approach for multi-purposes object-oriented programming languages in the style of Java and C#. Our approach includes the definition of a test specification language which results from extending the programming language with new designated specification constr

  17. Lack of evidence for neonatal misoprostol neurodevelopmental toxicity in C57BL6/J mice.

    Directory of Open Access Journals (Sweden)

    Claire M Koenig

    Full Text Available Misoprostol is a synthetic analogue of prostaglandin E1 that is administered to women at high doses to induce uterine contractions for early pregnancy termination and at low doses to aid in cervical priming during labor. Because of the known teratogenic effects of misoprostol when given during gestation and its effects on axonal growth in vitro, we examined misoprostol for its potential as a neurodevelopmental toxicant when administered to neonatal C57BL6/J mice. Mice were injected subcutaneously (s.c. with 0.4, 4 or 40 µg/kg misoprostol on postnatal day 7, the approximate developmental stage in mice of human birth, after which neonatal somatic growth, and sensory and motor system development were assessed. These doses were selected to span the range of human exposure used to induce labor. In addition, adult mice underwent a battery of behavioral tests relevant to neurodevelopmental disorders such as autism including tests for anxiety, stereotyped behaviors, social communication and interactions, and learning and memory. No significant effects of exposure were found for any measure of development or behavioral endpoints. In conclusion, the results of the present study in C57BL/6J mice do not provide support for neurodevelopmental toxicity after misoprostol administration approximating human doses and timed to coincide with the developmental stage of human birth.

  18. XAS at the materials science X-ray beamline BL8 at the DELTA storage ring

    Energy Technology Data Exchange (ETDEWEB)

    Frahm, R; Wagner, R; Luetzenkirchen-Hecht, D [Fachbereich C - Physik, Bergische Universitaet Wuppertal, Gaussstrasse 20, 42097 Wuppertal (Germany); Herdt, A, E-mail: frahm@uni-wuppertal.d [Fachbereich Physik/DELTA, Technische Universitaet Dortmund, Maria-Goeppert-Mayer-Strasse 2, 44221 Dortmund (Germany)

    2009-11-15

    The hard X-ray beamline BL 8 at the 1.5 GeV electron storage ring DELTA is described, and experimental data of different fields of research are presented. Making use of the intense X-ray beam emitted by a superconducting wiggler, the beamline is dedicated to X-ray absorption experiments. Three different monochromator crystal pairs are permanently available for experiments in the spectral range from about 1 keV to ca. 25 keV photon energy. Results of reference materials show that high quality EXAFS data can be obtained using Si(111) and Si(311) monochromators. First measurements in the energy range between 1.2 and 5 keV have been accomplished using YB{sub 66}(400) monochromator crystals. The experimental hutch accommodates a unique 6-axis diffractometer which is well suited for all kinds of diffraction and absorption experiments, including the grazing incidence geometry. The diffractometer can carry heavy loads related to non-ambient sample environments such as e.g. ultrahigh vacuum sample stages or cryostats. Here we present typical results obtained at BL8 in different areas of materials science including investigations of dilute alloys by fluorescence mode EXAFS and the study of the structural changes associated with temperature induced spin transitions of metallo-supramolecular polyelectrolyte-amphiphile-complexes.

  19. Anomalous energy exchange in the gBL and quasilinear theories

    Science.gov (United States)

    Mynick, H. E.

    1992-05-01

    The rate of turbulence-induced energy exchange Ẇ0 between species is computed in the framework of the quasilinear and generalized Balescu-Lenard (gBL) transport theories, and the relationship between these two similar theories is thereby elucidated. For both theories, general formal expressions for Ẇ0 are developed and then applied to the trapped electron mode for illustration. The general expressions for Ẇ0 in the two theories are formally closely related, but can yield predictions of very different magnitude in concrete applications. The fact that quasilinear theory is not valid for saturated steady-state turbulence gives rise to certain peculiarities in its predictions for this normal experimental situation, such as permitting energy to flow from the cooler to the hotter species, even in the limit of thermal equilibrium, where real-space gradients vanish. The gBL theory may be viewed as a modification of quasilinear theory to be valid for steady-state turbulence, keeping extra terms due to the self-consistent back reaction of particles on the fluctuations, which are just such as to eliminate these peculiarities.

  20. Multi-walled carbon nanotube instillation impairs pulmonary function in C57BL/6 mice

    Directory of Open Access Journals (Sweden)

    Walters Dianne M

    2011-08-01

    Full Text Available Abstract Background Multi-walled carbon nanotubes (MWCNTs are widely used in many disciplines due to their unique physical and chemical properties. Therefore, some concerns about the possible human health and environmental impacts of manufactured MWCNTs are rising. We hypothesized that instillation of MWCNTs impairs pulmonary function in C57BL/6 mice due to development of lung inflammation and fibrosis. Methods MWCNTs were administered to C57BL/6 mice by oropharyngeal aspiration (1, 2, and 4 mg/kg and we assessed lung inflammation and fibrosis by inflammatory cell infiltration, collagen content, and histological assessment. Pulmonary function was assessed using a FlexiVent system and levels of Ccl3, Ccl11, Mmp13 and IL-33 were measured by RT-PCR and ELISA. Results Mice administered MWCNTs exhibited increased inflammatory cell infiltration, collagen deposition and granuloma formation in lung tissue, which correlated with impaired pulmonary function as assessed by increased resistance, tissue damping, and decreased lung compliance. Pulmonary exposure to MWCNTs induced an inflammatory signature marked by cytokine (IL-33, chemokine (Ccl3 and Ccl11, and protease production (Mmp13 that promoted the inflammatory and fibrotic changes observed within the lung. Conclusions These results further highlight the potential adverse health effects that may occur following MWCNT exposure and therefore we suggest these materials may pose a significant risk leading to impaired lung function following environmental and occupational exposures.