1,011 results on '"Celik, O."'
Search Results
2. MARAUDERS: A mission concept to probe volatile distribution and properties at the lunar poles with miniature impactors
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Riu, L., Ballouz, R.-L., Van wal, S., Çelik, O., Baresi, N., Boden, R., and Crites, S.
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- 2020
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3. Evaluation of Daily Patient Position Accuracy and Calculation of Setup Errors with Skin Markers and Surface-Guided Radiotherapy (SGRT) in Breast Cancer
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Bakıcıerler, G., primary, Karakoyun Celik, O., additional, Sindir, B., additional, Duran Can, Ö., additional, and Akgüngör, K., additional
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- 2023
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4. Constraints on the Emission Geometries and Spin Evolution of Gamma-ray Millisecond Pulsars
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Johnson, T. J., Venter, C., Harding, A. K., Guillemot, L., Smith, D. A., Kramer, M., Celik, O., Hartog, P. R. den, Ferrara, E. C., Hou, X., Lande, J., and Ray, P. S.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Millisecond pulsars (MSPs) are a growing class of gamma-ray emitters. Pulsed gamma-ray signals have been detected from more than 40 MSPs with the Fermi Large Area Telescope (LAT). The wider radio beams and more compact magnetospheres of MSPs enable studies of emission geometries over a broader range of phase space than non-recycled radio-loud gamma-ray pulsars. We have modeled the gamma-ray light curves of 40 LAT-detected MSPs using geometric emission models assuming a vacuum retarded-dipole magnetic field. We modeled the radio profiles using a single-altitude hollow-cone beam, with a core component when indicated by polarimetry; however, for MSPs with gamma-ray and radio light curve peaks occurring at nearly the same rotational phase we assume that the radio emission is co-located with the gamma rays and caustic in nature. The best-fit parameters and confidence intervals are determined using a maximum likelihood technique. We divide the light curves into three model classes, with gamma-ray peaks trailing (Class I), aligned (Class II) or leading (Class III) the radio peaks. Outer gap and slot gap (two-pole caustic) models best fit roughly equal numbers of Class I and II, while Class III are exclusively fit with pair-starved polar cap models. Distinguishing between the model classes based on typical derived parameters is difficult. We explore the evolution of magnetic inclination angle with period and spin-down power, finding possible correlations. While the presence of significant off-peak emission can often be used as a discriminator between outer gap and slot gap models, a hybrid model may be needed., Comment: Accepted for publication in ApJS, auxiliary files can be found at the entry for this paper at http://www-glast.stanford.edu/cgi-bin/pubpub
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- 2014
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5. Six millisecond pulsars detected by the Fermi Large Area Telescope and the radio/gamma-ray connection of millisecond pulsars
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Espinoza, C. M., Guillemot, L., Celik, O., Weltevrede, P., Stappers, B. W., Smith, D. A., Kerr, M., Zavlin, V. E., Cognard, I., Eatough, R. P., Freire, P. C. C., Janssen, G. H, Camilo, F., Desvignes, G., Hewitt, J. W., Hou, X., Johnston, S., Keith, M., Kramer, M., Lyne, A., Manchester, R. N., Ransom, S. M., Ray, P. S., Shannon, R., Theureau, G., and Webb, N.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
We report on the discovery of gamma-ray pulsations from five millisecond pulsars (MSPs) using the Fermi Large Area Telescope (LAT) and timing ephemerides provided by various radio observatories. We also present confirmation of the gamma-ray pulsations from a sixth source, PSR J2051-0827. Five of these six MSPs are in binary systems: PSRs J1713+0747, J1741+1351, J1600-3053 and the two black widow binary pulsars PSRs J0610-2100 and 2051-0827. The only isolated MSP is the nearby PSR J1024-0719, which is also known to emit X-rays. We present X-ray observations in the direction of PSRs J1600-3053 and J2051-0827. While the latter is firmly detected, we an only give upper limits for the X-ray flux of the former. There are no dedicated X-ray observations available for the other 3 objects. The MSPs mentioned above, together with most of the MSPs detected by Fermi, are used to put together a sample of 30 gamma-ray MSPs which is used to study the morphology and phase connection of radio and gamma-ray pulse profiles. We show that MSPs with pulsed gamma-ray emission which is phase aligned with the radio emission present the steepest radio spectra and the largest magnetic fields at the light cylinder among all MSPs. As well, we also observe a trend towards very low, or undetectable, radio linear polarisation levels. These properties could be attributed to caustic radio emission produced at a range of different altitudes in the magnetosphere. We note that most of these characteristics are also observed in the Crab pulsar, the only other radio pulsar known to exhibit phase-aligned radio and gamma-ray emission., Comment: 19 pages, 10 figures, 4 tables. Published by MNRAS
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- 2012
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6. Discovery of Nine Gamma-Ray Pulsars in Fermi-LAT Data Using a New Blind Search Method
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Pletsch, H. J., Guillemot, L., Allen, B., Kramer, M., Aulbert, C., Fehrmann, H., Ray, P. S., Barr, E. D., Belfiore, A., Camilo, F., Caraveo, P. A., Celik, O., Champion, D. J., Dormody, M., Eatough, R. P., Ferrara, E. C., Freire, P. C. C., Hessels, J. W. T., Keith, M., Kerr, M., de Luca, A., Lyne, A. G., Marelli, M., McLaughlin, M. A., Parent, D., Ransom, S. M., Razzano, M., Reich, W., Parkinson, P. M. Saz, Stappers, B. W., and Wolff, M. T.
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Astrophysics - High Energy Astrophysical Phenomena ,General Relativity and Quantum Cosmology - Abstract
We report the discovery of nine previously unknown gamma-ray pulsars in a blind search of data from the Fermi Large Area Telescope (LAT). The pulsars were found with a novel hierarchical search method originally developed for detecting continuous gravitational waves from rapidly rotating neutron stars. Designed to find isolated pulsars spinning at up to kHz frequencies, the new method is computationally efficient, and incorporates several advances, including a metric-based gridding of the search parameter space (frequency, frequency derivative and sky location) and the use of photon probability weights. The nine pulsars have spin frequencies between 3 and 12 Hz, and characteristic ages ranging from 17 kyr to 3 Myr. Two of them, PSRs J1803-2149 and J2111+4606, are young and energetic Galactic-plane pulsars (spin-down power above 6e35 erg/s and ages below 100 kyr). The seven remaining pulsars, PSRs J0106+4855, J0622+3749, J1620-4927, J1746-3239, J2028+3332, J2030+4415, J2139+4716, are older and less energetic; two of them are located at higher Galactic latitudes (|b| > 10 deg). PSR J0106+4855 has the largest characteristic age (3 Myr) and the smallest surface magnetic field (2e11 G) of all LAT blind-search pulsars. PSR J2139+4716 has the lowest spin-down power (3e33 erg/s) among all non-recycled gamma-ray pulsars ever found. Despite extensive multi-frequency observations, only PSR J0106+4855 has detectable pulsations in the radio band. The other eight pulsars belong to the increasing population of radio-quiet gamma-ray pulsars., Comment: 20 pages, 13 figures. Accepted for publication in the Astrophysical Journal
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- 2011
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7. Discovery of millisecond pulsars in radio searches of southern Fermi LAT sources
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Keith, M. J., Johnston, S., Ray, P. S., Ferrara, E. C., Parkinson, P. M. Saz, Celik, O., Belfiore, A., Donato, D., Cheung, C. C., Abdo, A. A., Camilo, F., Freire, P. C. C., Guillemot, L., Harding, A. K., Kramer, M., Michelson, P. F., Ransom, S. M., Romani, R. W., Smith, D. A., Thompson, D. J., Weltevrede, P., and Wood, K. S.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Using the Parkes radio telescope we have carried out deep observations of eleven unassociated gamma-ray sources. Periodicity searches of these data have discovered two millisecond pulsars, PSR J1103-5403 (1FGL J1103.9-5355) and PSR J2241-5236 (1FGL J2241.9-5236), and a long period pulsar, PSR J1604-44 (1FGL J1604.7-4443). In addition we searched for but did not detect any radio pulsations from six gammaray pulsars discovered by the Fermi satellite to a level of - 0.04 mJy (for pulsars with a 10% duty cycle). Timing of the millisecond pulsar PSR J1103-5403 has shown that its position is 9' from the centroid of the gamma-ray source. Since these observations were carried out, independent evidence has shown that 1FGL J1103.9-5355 is associated with the flat spectrum radio source PKS 1101-536. It appears certain that the pulsar is not associated with the gamma-ray source, despite the seemingly low probability of a chance detection of a radio millisecond pulsar. We consider that PSR J1604-44 is a chance discovery of a weak, long period pulsar and is unlikely to be associated with 1FGL J1604.7-4443. PSR J2241-5236 has a spin period of 2.2 ms and orbits a very low mass companion with a 3.5 hour orbital period. The relatively high flux density and low dispersion measure of PSR J2241-5236 makes it an excellent candidate for high precision timing experiments. The gamma-rays of 1FGL J2241.9-5236 have a spectrum that is well modelled by a power law with exponential cutoff, and phasebinning with the radio ephemeris results in a multi-peaked gamma-ray pulse profile. Observations with Chandra have identified a coincident X-ray source within 0.1" of the position of the pulsar obtained by radio timing, Comment: 9 Pages 6 Figures, for publication in MNRAS
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- 2011
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8. Radio and Gamma-Ray Constraints on the Emission Geometry and Birthplace of PSR J2043+2740
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Noutsos, A., Abdo, A. A., Ackermann, M., Ajello, M., Ballet, J., Barbiellini, G., Baring, M. G., Bastieri, D., Bechtol, K., Bellazzini, R., Berenji, B., Bonamente, E., Borgland, A. W., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Buehler, R., Busetto, G., Caliandro, G. A., Cameron, R. A., Camilo, F., Caraveo, P. A., Casandjian, J. M., Cecchi, C., Celik, O., Chaty, S., Chekhtman, A., Chiang, J., Ciprini, S., Claus, R., Cognard, I., Cohen-Tanugi, J., Colafrancesco, S., Cutini, S., Dermer, C. D., de Palma, F., Drell, P. S., Dumora, D., Espinoza, C. M., Favuzzi, C., Ferrara, E. C., Focke, W. B., Frailis, M., Freire, P. C. C., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Germani, S., Giglietto, N., Giordano, F., Giroletti, M., Godfrey, G., Grandi, P., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Harding, A. K., Hughes, R. E., Jackson, M. S., Johannesson, G., Johnson, A. S., Johnson, T. J., Johnson, W. N., Johnston, S., Kamae, T., Katagiri, H., Kataoka, J., Knoedlseder, J., Kramer, M., Kuss, M., Lande, J., Lee, S. -H., Longo, F., Loparco, F., Lovellette, M. N., Lubrano, P., Lyne, A. G., Makeev, A., Marelli, M., Mazziotta, M. N., McEnery, J. E., Mehault, J., Michelson, P. F., Mizuno, T., Monte, C., Monzani, M. E., Morselli, A., Moskalenko, I. V., Murgia, S., Naumann-Godo, M., Nolan, P. L., Nuss, E., Ohsugi, T., Okumura, A., Omodei, N., Orlando, E., Ormes, J. F., Panetta, J. H., Parent, D., Pelassa, V., Pepe, M., Persic, M., Pesce-Rollins, M., Piron, F., Porter, T. A., Rain, S., Ray, P. S., Razzano, M., Reimer, A., Reimer, O., Reposeur, T., Romani, R. W., Sadrozinski, H. F. -W., Sander, A., Parkinson, P. M. Saz, Sgro, C., Siskind, E. J., Smith, D. A., Smith, P. D., Spandre, G., Spinelli, P., Stappers, B. W., Strickman, M. S., Suson, D. J., Takahashi, H., Tanaka, T., Theureau, G., Thompson, D. J., Thorsett, S. E., Tibolla, O., Torres, D. F., Tramacere, A., Usher, T. L., Vandenbroucke, J., Vianello, G., Vilchez, N., Villata, M., Vitale, V., von Kienlin, A., Waite, A. P., Wang, P., Watters, K., Weltevrede, P., Winer, B. L., Wood, K. S., and Ziegler, M.
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Astrophysics - Astrophysics of Galaxies - Abstract
We report on the first year of Fermi gamma-ray observations of pulsed high-energy emission from the old PSR J2043+2740. The study of the gamma-ray efficiency of such old pulsars gives us an insight into the evolution of pulsars' ability to emit in gammma rays as they age. The gamma-ray lightcurve of this pulsar above 0.1 GeV is clearly defined by two sharp peaks, 0.353+/-0.035 periods apart. We have combined the gamma-ray profile characteristics of PSR J2043+2740 with the geometrical properties of the pulsar's radio emission, derived from radio polarization data, and constrained the pulsar-beam geometry in the framework of a Two Pole Caustic and an Outer Gap model. The ranges of magnetic inclination and viewing angle were determined to be {alpha,zeta}~{52-57,61-68} for the Two Pole Caustic model, and {alpha,zeta}~{62-73,74-81} and {alpha,zeta}~{72-83,60-75} for the Outer Gap model. Based on this geometry, we assess possible birth locations for this pulsar and derive a likely proper motion, sufficiently high to be measurable with VLBI. At a characteristic age of 1.2 Myr, PSR J2043+2740 is the third oldest of all discovered, non-recycled, gamma-ray pulsars: it is twice as old as the next oldest, PSR J0357+32, and younger only than the recently discovered PSR J1836+5925 and PSR J2055+25, both of which are at least 5 and 10 times less energetic, respectively., Comment: 17 pages, 6 figures, Accepted for publication in ApJ
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- 2010
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9. Three Millisecond Pulsars in FERMI LAT Unassociated Bright Sources
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Ransom, S. M., Ray, P. S., Camilo, F., Roberts, M. S. E., Celik, O., Wolff, M. T., Cheung, C. C., Kerr, M., Pennucci, T., DeCesar, M. E., Cognard, I., Lyne, A. G., Stappers, B. W., Freire, P. C. C., Grove, J. E., Abdo, A. A., Desvignes, G., Donato, D., Ferrara, E. C., Gehrels, N., Guillemot, L., Gwon, C., Harding, A. K., Johnston, S., Keith, M., Kramer, M., Michelson, P. F., Parent, D., Parkinson, P. M. Saz, Romani, R. W., Smith, D. A., Theureau, G., Thompson, D. J., Weltevrede, P., Wood, K. S., and Ziegler, M.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Solar and Stellar Astrophysics - Abstract
We searched for radio pulsars in 25 of the non-variable, unassociated sources in the Fermi LAT Bright Source List with the Green Bank Telescope at 820 MHz. We report the discovery of three radio and gamma-ray millisecond pulsars (MSPs) from a high Galactic latitude subset of these sources. All of the pulsars are in binary systems, which would have made them virtually impossible to detect in blind gamma-ray pulsation searches. They seem to be relatively normal, nearby (<=2 kpc) millisecond pulsars. These observations, in combination with the Fermi detection of gamma-rays from other known radio MSPs, imply that most, if not all, radio MSPs are efficient gamma-ray producers. The gamma-ray spectra of the pulsars are power-law in nature with exponential cutoffs at a few GeV, as has been found with most other pulsars. The MSPs have all been detected as X-ray point sources. Their soft X-ray luminosities of ~10^{30-31} erg/s are typical of the rare radio MSPs seen in X-rays., Comment: Accepted for publication in ApJ Letters
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- 2010
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10. The Spectral Energy Distribution of Fermi bright blazars
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Abdo, A. A., Ackermann, M., Ajello, M., Axelsson, M., Baldini, L., Ballet, J., Barbiellini, G., Bastieri, D., Baughman, B. M., Bechtol, K., Bellazzini, R., Berenji, B., Blandford, R. D., Bloom, E. D., Bonamente, E., Borgland, A., Bregeon, J., Brez, A., Brigida, M., Bruel, P., Burnett, T. H., Buson, S., Caliandro, G. A., Cameron, R. A., Caraveo, P. A., Casandjian, J. M., Cavazzuti, E., Cecchi, C., Celik, O., Charles, E., Chaty, S., Chekhtman, A., Chiang, J., Ciprini, S., Claus, R., Cohen-Tanugi, J., Colafrancesco, S., Cominsky, L. R., Conrad, J., Costamante, L., Cutini, S., Dermer, C. D., de Angelis, A., de Palma, F., Digel, S. W., Silva, E. do Couto e, Drell, P. S., Dubois, R., Dumora, D., Farnier, C., Favuzzi, C., Fegan, S. J., Focke, W. B., Fortin, P., Frailis, M., Fuhrmann, L., Fukazawa, Y., Funk, S., Fusco, P., Gargano, F., Gasparrini, D., Gehrels, N., Germani, S., Giebels, B., Giglietto, N., Giommi, P., Giordano, F., Glanzman, T., Godfrey, G., Grenier, I. A., Grove, J. E., Guillemot, L., Guiriec, S., Hadasch, D., Hanabata, Y., Harding, A. K., Hayashida, M., Hays, E., Healey, S. E., Horan, D., Hughes, R. E., Itoh, R., Jackson, M. S., Johannesson, G., Johnson, A. S., Johnson, W. N., Kadler, M., Kamae, T., Katagiri, H., Kataoka, J., Kawai, N., Kerr, M., Knodlseder, J., Kocian, M. L., Kuss, M., Lande, J., Latronico, L., Longo, F., Loparco, F., Lott, B., Lovellette, M. N., Lubrano, P., Madejski, G. M., Makeev, A., Max-Moerbeck, W., Mazziotta, M. N., McConville, W., McEnery, J. E., Meurer, C., and Michelson, P. F.
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Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
(Abridged) We have conducted a detailed investigation of the broad-band spectral properties of the \gamma-ray selected blazars of the Fermi LAT Bright AGN Sample (LBAS). By combining our accurately estimated Fermi gamma-ray spectra with Swift, radio, infra-red, optical and other hard X-ray/gamma-ray data, collected within three months of the LBAS data taking period, we were able to assemble high-quality and quasi-simultaneous Spectral Energy Distributions (SED) for 48 LBAS blazars.The SED of these gamma-ray sources is similar to that of blazars discovered at other wavelengths, clearly showing, in the usual Log $\nu $ - Log $\nu$ F$_\nu$ representation, the typical broad-band spectral signatures normally attributed to a combination of low-energy synchrotron radiation followed by inverse Compton emission of one or more components. We have used these SEDs to characterize the peak intensity of both the low and the high-energy components. The results have been used to derive empirical relationships that estimate the position of the two peaks from the broad-band colors (i.e. the radio to optical and optical to X-ray spectral slopes) and from the gamma-ray spectral index. Our data show that the synchrotron peak frequency $\nu_p^S$ is positioned between 10$^{12.5}$ and 10$^{14.5}$ Hz in broad-lined FSRQs and between $10^{13}$ and $10^{17}$ Hz in featureless BL Lacertae objects.We find that the gamma-ray spectral slope is strongly correlated with the synchrotron peak energy and with the X-ray spectral index, as expected at first order in synchrotron - inverse Compton scenarios. However, simple homogeneous, one-zone, Synchrotron Self Compton (SSC) models cannot explain most of our SEDs, especially in the case of FSRQs and low energy peaked (LBL) BL Lacs. (...), Comment: 85 pages, 38 figures, submitted to ApJ
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- 2009
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11. A connection between star formation activity and cosmic rays in the starburst galaxy M 82
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Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Celik, O., Cesarini, A., Chow, Y. C., Ciupik, L., Cogan, P., Colin, P., Cui, W., Dickherber, R., Duke, C., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McArthur, S., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pizlo, F., 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., Theiling, M., Thibadeau, S., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
Although Galactic cosmic rays (protons and nuclei) are widely believed to be dominantly accelerated by the winds and supernovae of massive stars, definitive evidence of this origin remains elusive nearly a century after their discovery [1]. The active regions of starburst galaxies have exceptionally high rates of star formation, and their large size, more than 50 times the diameter of similar Galactic regions, uniquely enables reliable calorimetric measurements of their potentially high cosmic-ray density [2]. The cosmic rays produced in the formation, life, and death of their massive stars are expected to eventually produce diffuse gamma-ray emission via their interactions with interstellar gas and radiation. M 82, the prototype small starburst galaxy, is predicted to be the brightest starburst galaxy in gamma rays [3, 4]. Here we report the detection of >700 GeV gamma rays from M 82. From these data we determine a cosmic-ray density of 250 eV cm-3 in the starburst core of M 82, or about 500 times the average Galactic density. This result strongly supports that cosmic-ray acceleration is tied to star formation activity, and that supernovae and massive-star winds are the dominant accelerators., Comment: 18 pages, 4 figures; published in Nature; Version is prior to Nature's in-house style editing (differences are minimal)
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- 2009
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12. VERITAS Upper Limit on the VHE Emission from the Radio Galaxy NGC 1275
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., Boltuch, D., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K., Cannon, A., Celik, O., Cesarini, A., Ciupik, L., Cogan, P., Cui, W., Dickherber, R., Duke, C., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Galante, N., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Theiling, M., Toner, J. A., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., Zitzer, B., Kataoka, J., Cavazzuti, E., Cheung, C. C., Lott, B., Thompson, D. J., and Tosti, G.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
The recent detection by the Fermi gamma-ray space telescope of high-energy gamma-rays from the radio galaxy NGC 1275 makes the observation of the very high energy (VHE: E > 100 GeV) part of its broadband spectrum particularly interesting, especially for the understanding of active galactic nuclei (AGN) with misaligned multi-structured jets. The radio galaxy NGC 1275 was recently observed by VERITAS at energies above 100 GeV for about 8 hours. No VHE gamma-ray emission was detected by VERITAS from NGC 1275. A 99% confidence level upper limit of 2.1% of the Crab Nebula flux level is obtained at the decorrelation energy of approximately 340 GeV, corresponding to 19% of the power-law extrapolation of the Fermi Large Area Telescope (LAT) result., Comment: Accepted for publication in ApJ Letters
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- 2009
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13. Observation of Extended VHE Emission from the Supernova Remnant IC 443 with VERITAS
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Aune, T., Bautista, M., Beilicke, M., Benbow, W., 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., Daniel, M. K., Dickherber, R., Duke, C., Dwarkadas, V. V., Ergin, T., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L., Furniss, A., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Hays, E., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Ong, R. A., Otte, A. N., Pandel, D., Perkins, J. S., 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., Theiling, M., Toner, J. A., Valcarcel, L., Varlotta, A., Vassiliev, V. V., Vincent, S., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Weisgarber, T., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Galaxy Astrophysics - Abstract
We present evidence that the very-high-energy (VHE, E > 100 GeV) gamma-ray emission coincident with the supernova remnant IC 443 is extended. IC 443 contains one of the best-studied sites of supernova remnant/molecular cloud interaction and the pulsar wind nebula CXOU J061705.3+222127, both of which are important targets for VHE observations. VERITAS observed IC 443 for 37.9 hours during 2007 and detected emission above 300 GeV with an excess of 247 events, resulting in a significance of 8.3 standard deviations (sigma) before trials and 7.5 sigma after trials in a point-source search. The emission is centered at 06 16 51 +22 30 11 (J2000) +- 0.03_stat +- 0.08_sys degrees, with an intrinsic extension of 0.16 +- 0.03_stat +- 0.04_sys degrees. The VHE spectrum is well fit by a power law (dN/dE = N_0 * (E/TeV)^-Gamma) with a photon index of 2.99 +- 0.38_stat +- 0.3_sys and an integral flux above 300 GeV of (4.63 +- 0.90_stat +- 0.93_sys) * 10^-12 cm^-2 s^-1. These results are discussed in the context of existing models for gamma-ray production in IC 443., Comment: 7 pages, accepted by ApJL
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- 2009
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14. VERITAS Observations of a Very High Energy Gamma-ray Flare from the Blazar 3C 66A
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Arlen, T., Beilicke, M., Benbow, W., Bottcher, 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., Cui, W., Daniel, M. K., Dickherber, R., Ergin, T., Falcone, A., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L., Furniss, A., Gall, D., Gibbs, K., Gillanders, G. H., Godambe, S., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Hays, E., Holder, J., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, 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., Pizlo, F., 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., Theiling, M., Toner, J. A., Varlotta, A., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., Williams, D. A., Wissel, S., Wood, M., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Extragalactic Astrophysics - Abstract
The intermediate-frequency peaked BL Lacertae (IBL) object 3C 66A is detected during 2007 - 2008 in VHE (very high energy: E > 100 GeV) gamma-rays with the VERITAS stereoscopic array of imaging atmospheric Cherenkov telescopes. An excess of 1791 events is detected, corresponding to a significance of 21.2 standard deviations (sigma), in these observations (32.8 hours live time). The observed integral flux above 200 GeV is 6% of the Crab Nebula's flux and shows evidence for variability on the time-scale of days. The measured energy spectrum is characterized by a soft power law with photon index Gamma = 4.1 +- 0.4_stat +- 0.6_sys. The radio galaxy 3C 66B is excluded as a possible source of the VHE emission., Comment: 13 Pages, 4 Figures. Published in ApJL. This new version correctly calculates the intrinsic photon index (see Erratum: ApJL, 721:L203-L204)
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- 2009
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15. VERITAS observations of the BL Lac 1ES 1218+304
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VERITAS Collaboration, Acciari, V. A., Aliu, E., 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, P., Karlsson, N., Kertzman, M., Kieda, D. B., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, 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., Vassiliev, 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., and Zitzer, B.
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Astrophysics - High Energy Astrophysical Phenomena ,Astrophysics - Cosmology and Nongalactic Astrophysics - Abstract
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 Gamma = 2.32 +/- 0.37_stat. When including constraints from the spectra of 1ES 1101-232 and 1ES 0229+200, the spectrum of 1ES 1218+304 is likely to be harder than Gamma = 1.86 +/- 0.37_stat., Comment: Accepted for publication in The Astrophysical Journal
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- 2009
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16. Multiwavelength Observations of Markarian 421 in 2005 - 2006
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Horan, D., Acciari, V. A., Bradbury, S. M., Buckley, J. H., Bugaev, V., Byrum, K. L., Cannon, A., Celik, O., Cesarini, A., Chow, Y. C. K., Ciupik, L., Cogan, P., Falcone, A. D., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gall, D., Gillanders, G. H., Grube, J., Gyuk, G., Hanna, D., Hays, E., Kertzman, M., Kildea, J., Konopelko, A., Krawczynski, H., Lang, M. J., Lee, K., Moriarty, P., Nagai, T., Niemiec, J., Ong, R. A., Perkins, J. S., Pohl, M., Quinn, J., Reynolds, P. T., Rose, H. J., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Toner, J. A., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., White, R. J., Williams, D. A., Wood, M. D., Zitzer, B., Aller, H. D., Aller, M. F., Baker, M., Barnaby, D., Carini, M. T., Charlot, P., Dumm, J. P., Fields, N. E., Hovatta, T., Jordan, B., Kovalev, Y. A., Kovalev, Y. Y., Krimm, H. A., Kurtanidze, O. M., Lahteenmaki, A., Campion, J. F. Le, Maune, J., Montaruli, T., Sadun, A. C., Smith, S., Tornikoski, M., Turunen, M., and Walters, R.
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Astrophysics - High Energy Astrophysical Phenomena - Abstract
Since September 2005, the Whipple 10m Gamma-ray Telescope has been operated primarily as a blazar monitor. The five Northern Hemisphere blazars that have already been detected at the Whipple Observatory, Markarian 421, H1426+428, Markarian 501, 1ES 1959+650 and 1ES 2344+514, are monitored routinely each night that they are visible. We report on the Markarian 421 observations taken from November 2005 to June 2006 in the gamma-ray, X-ray, optical and radio bands. During this time, Markarian 421 was found to be variable at all wavelengths probed. Both the variability and the correlations among different energy regimes are studied in detail here. A tentative correlation, with large spread, was measured between the X-ray and gamma-ray bands, while no clear correlation was evident among the other energy bands. In addition to this, the well-sampled spectral energy distribution of Markarian 421 (1101+384) is presented for three different activity levels. The observations of the other blazar targets will be reported separately., Comment: 58 pages, 22 Figures. Accepted for publication in ApJ
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- 2009
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17. Early predictive factors and risk assessment for anastomotic leakage in patients undergoing low anterior resection for rectal cancer.
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OZGUL, H., DOGAN, U., CAKIR, R. C., UZMAY, Y., ENSARI, C. O., CELIK, O., KAPLAN, T. T., and ASLANER, A.
- Abstract
OBJECTIVE: Anastomotic leakage is a complication that creates significant concern in terms of postoperative morbidity and mortality after colorectal surgery. This study aimed to identify variables for detecting anastomotic leakage in those who had open, laparoscopic, or robotic low anterior resection for cancer and to explore their relationships. PATIENTS AND METHODS: A total of 283 patients who were diagnosed with rectal cancer and underwent low anterior resection were divided into two groups: those with and without anastomotic leakage. Demographic and clinical data were analyzed. Anastomotic leakage was detected in 23 of 283 patients who underwent low anterior resection. RESULTS: The postoperative analysis of the biochemical data of the patients showed statistically significant differences between the two groups in terms of C-reactive protein (Crp), albumin, lymphocytes, leukocytes, neutrophils, and their ratio. The performance of these parameters in predicting anastomotic leakage was statistically analyzed in the patient group with anastomotic leakage, and nomogram results were acquired. Immune system components and biomarkers were statistically tested, and nomogram results were obtained in rectal cancer patients. CONCLUSIONS: These parameters can be used together as a potential marker in anastomotic leakage. Further development of these variables has the potential to facilitate the timely detection and treatment of anastomotic leakage. [ABSTRACT FROM AUTHOR]
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- 2024
18. Discovery of Very High-Energy Gamma-Ray Radiation from the BL Lac 1ES 0806+524
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VERITAS Collaboration, Acciari, V., Aliu, E., Arlen, T., 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, P., Karlsson, N., Kertzman, M., Kieda, D., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, 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., Vassiliev, 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., and Zitzer, B.
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Astrophysics - Abstract
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 spectral energy distribution that can be reasonably described using a synchrotron-self Compton model., Comment: 14 pages, 4 figures, accepted to APJL
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- 2008
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19. Status of the VERITAS Observatory
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Holder, J., Acciari, V. A., Aliu, E., Arlen, T., Beilicke, M., Benbow, W., Bradbury, S. M., Buckley, J. H., Bugaev, V., Butt, Y., Byrum, K. L., Cannon, A., 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., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Hays, E., Horan, D., Hui, C. M., Humensky, T. B., Imran, A., Kaaret, P., Karlsson, N., Kertzman, M., Kieda, D. B., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, 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., Vassiliev, 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., and Zitzer, B.
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Astrophysics - Abstract
VERITAS, an Imaging Atmospheric Cherenkov Telescope (IACT) system for gammma-ray astronomy in the GeV-TeV range, has recently completed its first season of observations with a full array of four telescopes. A number of astrophysical gamma-ray sources have been detected, both galactic and extragalactic, including sources previously unknown at TeV energies. We describe the status of the array and some highlight results, and assess the technical performance, sensitivity and shower reconstruction capabilities., Comment: Submitted to Proceedings of "4th Heidelberg International Symposium on High Energy Gamma-Ray Astronomy 2008"
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- 2008
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20. VERITAS Discovery of >200GeV Gamma-ray Emission from the Intermediate-frequency-peaked BL Lac Object W Comae
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VERITAS Collaboration, Acciari, V. A., Aliu, E., Beilicke, M., Benbow, W., Boettcher, M., 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, P., Karlsson, N., Kertzman, M., Kieda, D. B., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, 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., Vassiliev, 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., and Zitzer, B.
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Astrophysics - Abstract
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., Comment: 7 pages, 4 figures, accepted by ApJL
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- 2008
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21. VERITAS Observations of the gamma-Ray Binary LS I +61 303
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Acciari, V. A., Beilicke, M., Blaylock, G., 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., Duke, C., Ergin, T., Falcone, A. D., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gall, D., Gibbs, K., Gillanders, G. H., Guenette, J. Grube R., Hanna, D., Hays, E., Holder, J., Horan, D., Hughes, S. B., Hui, C. M., Humensky, T. B., Kaaret, P., Kieda, D. B., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Lee, K., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R. A., Pandel, D., Perkins, J. S., Pizlo, F., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Toner, J. A., Valcarcel, L., Vassiliev, 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., and Zitzer, B.
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Astrophysics - Abstract
LS I +61 303 is one of only a few high-mass X-ray binaries currently detected at high significance in very high energy gamma-rays. The system was observed over several orbital cycles (between September 2006 and February 2007) with the VERITAS array of imaging air-Cherenkov telescopes. A signal of gamma-rays with energies above 300 GeV is found with a statistical significance of 8.4 standard deviations. The detected flux is measured to be strongly variable; the maximum flux is found during most orbital cycles at apastron. The energy spectrum for the period of maximum emission can be characterized by a power law with a photon index of Gamma=2.40+-0.16_stat+-0.2_sys and a flux above 300 GeV corresponding to 15-20% of the flux from the Crab Nebula., Comment: accepted for publication in The Astrophysical Journal
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- 2008
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22. Observation of gamma-ray emission from the galaxy M87 above 250 GeV with VERITAS
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Acciari, V. A., Beilicke, M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Bugaev, V., Butt, Y., Celik, O., Cesarini, A., Ciupik, L., Cogan, P., Colin, P., Cui, W., Daniel, M. K., Duke, C., Ergin, T., Falcone, A. D., Fegan, S. J., Finley, J. P., Finnegan, G., Fortin, P., Fortson, L. F., Gibbs, K., Gillanders, G. H., Grube, J., Guenette, R., Gyuk, G., Hanna, D., Hays, E., Holder, J., Horan, D., Hughes, S. B., Hui, M. C., Humensky, T. B., Imran, A., Kaaret, P., Kertzman, M., Kieda, D. B., Kildea, J., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Lee, K., Maier, G., McCann, A., McCutcheon, M., Millis, J., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R. A., Pandel, D., Perkins, J. S., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Smith, A. W., Steele, D., Swordy, S. P., Toner, A. Syson J. A., Valcarcel, L., Vassiliev, V. V., Wakely, S. P., Ward, J. E., Weekes, T. C., Weinstein, A., White, R. J., Williams, D. A., Wissel, S. A., Wood, M. D., and Zitzer, B.
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Astrophysics - Abstract
The multiwavelength observation of the nearby radio galaxy M87 provides a unique opportunity to study in detail processes occurring in Active Galactic Nuclei from radio waves to TeV gamma-rays. Here we report the detection of gamma-ray emission above 250 GeV from M87 in spring 2007 with the VERITAS atmospheric Cherenkov telescope array and discuss its correlation with the X-ray emission. The gamma-ray emission is measured to be point-like with an intrinsic source radius less than 4.5 arcmin. The differential energy spectrum is fitted well by a power-law function: dPhi/dE=(7.4+-1.3_{stat}+-1.5_{sys})(E/TeV)^{-2.31+-0.17_{stat}+-0.2_{sys}} 10^{-9}m^{-2}s^{-1}TeV^{-1}. We show strong evidence for a year-scale correlation between the gamma-ray flux reported by TeV experiments and the X-ray emission measured by the ASM/RXTE observatory, and discuss the possible short-time-scale variability. These results imply that the gamma-ray emission from M87 is more likely associated with the core of the galaxy than with other bright X-ray features in the jet., Comment: 10 pages, 7 figures, accepted for publication in The Astrophysical Journal
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- 2008
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23. Observations of the Crab Nebula and Pulsar with VERITAS
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Celik, O.
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Astrophysics - Abstract
Observations of the Crab Nebula have proven to be the best tool to calibrate and to characterize the performance of a Cherenkov telescope. Scientifically, it is interesting to measure the energy spectrum of the Crab Nebula close to the inverse-Compton peak where a deviation is expected from the power law seen at energies above 300 GeV. Additionally, it is important to search for pulsed emission from the Crab Pulsar at energies beyond the 10 GeV upper limit of the EGRET pulsar detection. Since current models predict a cut-off in pulsed emission between 10 and 100 GeV, measurements at energies close to this range may help to discriminate between them. We observed the Crab extensively in the 2006-2007 season during the VERITAS 2- and 3-telescope commissioning phases. Using this data set we reconstructed a preliminary energy spectrum of the signal from the Crab Nebula. We also measured the optical pulsed signal to validate our GPS time-stamping and barycentering techniques and obtained an upper limit for the pulsed emission at gamma-ray energies., Comment: 4 pages; contribution to the 30th International Cosmic Ray Conference, Merida, Mexico, July 2007
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- 2007
24. Very High Energy Observations of Gamma-Ray Burst Locations with the Whipple Telescope
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Horan, D., Atkins, R. W., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Byrum, K. L., Celik, O., Chow, Y. C. K., Cogan, P., Cui, W., Daniel, M. K., Perez, I. de la Calle, Dowdall, C., Falcone, A. D., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gillanders, G. H., Grube, J., Gutierrez, K. J., Hall, J., Hanna, D., Holder, J., Hughes, S. B., Humensky, T. B., Kenny, G. E., Kertzman, M., Kieda, D. B., Kildea, J., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Maier, G., Moriarty, P., Nagai, T., Ong, R. A., Perkins, J. S., Petry, D., Quinn, J., Quinn, M., Ragan, K., Reynolds, P. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Steele, D., Swordy, S. P., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Weekes, T. C., White, R. J., and Williams, D. A.
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Astrophysics - Abstract
Gamma-ray burst (GRB) observations at very high energies (VHE, E > 100 GeV) can impose tight constraints on some GRB emission models. Many GRB afterglow models predict a VHE component similar to that seen in blazars and plerions, in which the GRB spectral energy distribution has a double-peaked shape extending into the VHE regime. VHE emission coincident with delayed X-ray flare emission has also been predicted. GRB follow-up observations have had high priority in the observing program at the Whipple 10m Gamma-ray Telescope and GRBs will continue to be high priority targets as the next generation observatory, VERITAS, comes on-line. Upper limits on the VHE emission, at late times (>~4 hours), from seven GRBs observed with the Whipple Telescope are reported here., Comment: Accepted for publication in the January 20, 2007 volume of the Astrophysical Journal, 655, 396
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- 2007
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25. Observations of the Unidentified TeV Gamma-Ray Source TeV J2032+4130 with the Whipple Observatory 10 m Telescope
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Konopelko, A., Atkins, R. W., Blaylock, G., Buckley, J. H., Butt, Y., Carter-Lewis, D. A., Celik, O., Cogan, P., Chow, Y. C. K., Cui, W., Dowdall, C., Ergin, T., Falcone, A. D., Fegan, D. J., Fegan, S. J., Finley, J. P., Fortin, P., Gillanders, G. H., Gutierrez, K. J., Hall, J., Hanna, D., Horan, D., Hughes, S. B., Humensky, T. B., Imran, A., Jung, I., Kaaret, P., Kenny, G. E., Kertzman, M., Kieda, D. B., Kildea, J., Knapp, J., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Moriarty, P., Mukherjee, R., Nagai, T., Ong, R. A., Perkins, J. S., Pohl, M., Ragan, K., Reynolds, P. T., Rose, H. J., Sembroski, G. H., Schroedter, M., Smith, A. W., Steele, D., Syson, A., Swordy, S. P, Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Weekes, T. C., White, R. J., Williams, D. A., and Zitzer, B.
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Astrophysics - Abstract
We report on observations of the sky region around the unidentified TeV gamma-ray source TeV J2032+4130 carried out with the Whipple Observatory 10 m atmospheric Cherenkov telescope for a total of 65.5 hrs between 2003 and 2005. The standard two-dimensional analysis developed by the Whipple collaboration for a stand-alone telescope reveals an excess in the field of view at a pre-trials significance level of 6.1 standard deviations. The measured position of this excess is alpha(2000) =20 h 32 m 27 s, delta(2000) = 41 deg 39 min 17 s. The estimated integral flux for this gamma-ray source is about 8% of the Crab-Nebula flux. The data are consistent with a point-like source. Here we present a detailed description of the standard two-dimensional analysis technique used for the analysis of data taken with the Whipple Observatory 10 m telescope and the results for the TeV J2032+4130 campaign. We include a short discussion of the physical mechanisms that may be responsible for the observed gamma-ray emission, based on possible association with known astrophysical objects, in particular Cygnus OB2., Comment: Accepted for publication in the Astrophysical Journal
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- 2006
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26. The First VERITAS Telescope
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Holder, J., Atkins, R. W., Badran, H. M., Blaylock, G., Bradbury, S. M., Buckley, J. H., Byrum, K. L., Carter-Lewis, D. A., Celik, O., Chow, Y. C. K., Cogan, P., Cui, W., Daniel, M. K., Perez, I. de la Calle, Dowdall, C., Dowkontt, P., Duke, C., Falcone, A. D., Fegan, S. J., Finley, J. P., Fortin, P., Fortson, L. F., Gibbs, K., Gillanders, G., Glidewell, O. J., Grube, J., Gutierrez, K. J., Gyuk, G., Hall, J., Hanna, D., Hays, E., Horan, D., Hughes, S. B., Humensky, T. B., Imran, A., Jung, I., Kaaret, P., Kenny, G. E., Kieda, D., Kildea, J., Knapp, J., Krawczynski, H., Krennrich, F., Lang, M. J., LeBohec, S., Linton, E., Little, E. K., Maier, G., Manseri, H., Milovanovic, A., Moriarty, P., Mukherjee, R., Ogden, P. A., Ong, R. A., Perkins, J. S., Pizlo, F., Pohl, M., Quinn, J., Ragan, K., Reynolds, P. T., Roache, E. T., Rose, H. J., Schroedter, M., Sembroski, G. H., Sleege, G., Steele, D., Swordy, S. P., Syson, A., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wakely, S. P., Weekes, T. C., White, R. J., Williams, D. A., and Wagner, R.
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Astrophysics - Abstract
The first atmospheric Cherenkov telescope of VERITAS (the Very Energetic Radiation Imaging Telescope Array System) has been in operation since February 2005. We present here a technical description of the instrument and a summary of its performance. The calibration methods are described, along with the results of Monte Carlo simulations of the telescope and comparisons between real and simulated data. The analysis of TeV $\gamma$-ray observations of the Crab Nebula, including the reconstructed energy spectrum, is shown to give results consistent with earlier measurements. The telescope is operating as expected and has met or exceeded all design specifications., Comment: Accepted by Astroparticle Physics
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- 2006
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27. Multiwavelength Observations of 1ES 1959+650, One Year After the Strong Outburst of 2002
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Gutierrez, K., Badran, H. M., Bradbury, S. M., Buckley, J. H., Celik, O., Chow, Y. C., Cogan, P., Cui, W., Daniel, M., Falcone, A., Fegan, S. J., Finley, J. P., Gillanders, G. H., Grube, J., Holder, J., Horan, D., Hughes, S. B., Jung, I., Kieda, D., Kosack, K., Krawczynski, H., Krennrich, F., Lang, M. J., Bohec, S. Le, Maier, G., Moriarty, P., Perkins, J., Pohl, M., Quinn, J., Rebillot, P. F., Rose, H. J., Schroedter, M., Sembroski, G. H., Wakely, S. P., Weekes, T. C., and White, R. J.
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Astrophysics - Abstract
In April-May 2003, the blazar 1ES 1959+650 showed an increased level of X-ray activity. This prompted a multiwavelength observation campaign with the Whipple 10 m gamma-ray telescope, the Rossi X-ray Timing Explorer, the Bordeaux Optical Observatory, and the University of Michigan Radio Astrophysical Observatory. We present the multiwavelength data taken from May 2, 2003 to June 7, 2003 and compare the source characteristics with those measured during observations taken during the years 2000 and 2002. The X-ray observations gave a data set with high signal-to-noise light curves and energy spectra; however, the gamma-ray observations did not reveal a major TeV gamma-ray flare. Furthermore, we find that the radio and optical fluxes do not show statistically significant deviations from those measured during the 2002 flaring periods. While the X-ray flux and X-ray photon index appear correlated during subsequent observations, the apparent correlation evolved significantly between the years 2000, 2002, and 2003. We discuss the implications of this finding for the mechanism that causes the flaring activity., Comment: 17 pages, 6 figures, 2 tables
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- 2006
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28. Absolute calibration of imaging atmospheric Cherenkov telescopes
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Shepherd, N., Buckley, J. H., Celik, O., Holder, J., LeBohec, S., Manseri, H., Pizlo, F., and Roberts, M.
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Astrophysics - Abstract
A calibrated laser pulse propagating through the atmosphere produces a flash of Rayleigh scattered light with an intensity that can be calculated very accurately when atmospheric conditions are good. This is used in a technique developed for the absolute calibration of ultra high energy cosmic ray fluorescence telescopes, and it can also be applied to imaging atmospheric Cherenkov telescopes (IACTs). In this paper we present the absolute calibration system being constructed and tested for the VERITAS project., Comment: 4 pages, 2 figure, Submitted to the 29th ICRC, Pune
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- 2005
29. Elephantiasis nostras verrucosa on the abdomen of a Turkish female patient caused by morbid obesity
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Buyuktas, D, Arslan, E, Celik, O, Tasan, E, Demirkesen, C, and Gundogdu, S
- Published
- 2010
30. PO-1238 chemoradiotherapy induced hypomagnesemia is associated with superior survival in laryngeal cancer
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Karakoyun Celik, O., primary, Uncu, O., additional, and Ayaydin, B., additional
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- 2023
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31. FTIR Spectroscopy of Protein Isolates of Salt-Tolerant Soybean Mutants
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Akyuz, S., Akyuz, T., Celik, O., and Atak, C.
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- 2018
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32. A frequency and spatial domain decomposition method for operational strain modal analysis and its application
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Wang, T., Celik, O., Catbas, F.N., and Zhang, L.M.
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- 2016
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33. A Vision for Vision-based Technologies for Bridge Health Monitoring
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Catbas, N., primary, Dong, C.Z., additional, Celik, O., additional, and Khuc, T., additional
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- 2018
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34. The Treatment Outcomes of Oligometastatic Colorectal Cancer Patients Treated with Stereotactic Body Radiation Therapy: A Multi-Institutional Analysis TROD 02-008
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Guler, O.C., primary, Hurmuz, P., additional, Atalar, B., additional, Guney, Y. Yukselen, additional, Saglam, E.K., additional, Akyurek, S., additional, Bolukbasi, Y., additional, Güral, Z., additional, Tugrul, F., additional, Korcum, A.F., additional, Sen, C.A., additional, Yildirim, B. Akkus, additional, Oksuz, D.C., additional, Celik, O. Karakoyun, additional, Kurt, M., additional, Guzeloz, Z., additional, Yavas, G., additional, Ozyigit, G., additional, Aksu, M.G., additional, and Onal, C., additional
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- 2022
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35. The Treatment Outcomes of Patients with Cervical Esophageal Carcinoma Undergoing Definitive Chemoradiotherapy: A Multi-Institutional Analysis TROD 01-005
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Guler, O.C., primary, Oymak, E., additional, Yazici, G., additional, Akagunduz, O. Ozkaya, additional, Cetinayak, O., additional, Erpolat, P., additional, Aksoy, A., additional, Duzova, M., additional, Yildirim, B. Akkus, additional, Kurt, M., additional, Canyılmaz, E., additional, Akyurek, S., additional, Atalar, B., additional, Yavas, G., additional, Oksuz, D.C., additional, Saglam, E.K., additional, Celik, O. Karakoyun, additional, Cengiz, M., additional, and Onal, C., additional
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- 2022
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36. Adherence to GOLD guideline treatment recommendations among pulmonologists in Turkey
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Sen E, Guclu SZ, Kibar I, Ocal U, Yilmaz V, Celik O, Cimen F, Topcu F, Orhun M, Tereci H, Konya A, Ar I, and Saryal S
- Subjects
Adherence ,chronic obstructive pulmonary disease ,Global Initiative for Chronic Obstructive Lung Disease (GOLD) guidelines ,treatment approach ,Turkey ,Diseases of the respiratory system ,RC705-779 - Abstract
Elif Sen,1 Salih Zeki Guclu,2 Isil Kibar,3 Ulku Ocal,4 Veysel Yilmaz,5 Onur Celik,6 Filiz Cimen,7 Fusun Topcu,8 Meltem Orhun,9 Hikmet Tereci,10 Aylin Konya,11 Idilhan Ar,11 Sevgi Saryal11Department of Pulmonary Diseases, Ankara University School of Medicine, Ankara, 2Pulmonary Diseases Department, Izmir Dr Suat Seren Surgery Training and Research Hospital, Izmir, 3Pulmonary Diseases Department, Istanbul Hospital, Istanbul, 4Pulmonary Diseases Department, Adana Prof Dr Nusret Karasu Pulmonary Diseases Hospital, Adana, 5Pulmonary Diseases Department, Yedikule Pulmonary Diseases and Surgery Training and Research Hospital, Istanbul, 6Pulmonary Diseases Department, Nihat Kitapçi Pulmonary Diseases and Surgery Hospital, Erzurum, 7Pulmonary Diseases Department, Atatürk Pulmonary Diseases and Surgery Training and Research Hospital, Ankara, 8Department of Pulmonary Diseases, Dicle University School of Medicine, Diyarbakir, 9Pulmonary Diseases Department, Uskudar State Hospital, Istanbul, 10Pulmonary Diseases Department, Samsun Pulmonary Diseases and Thoracic Surgery Hospital, 11Pulmonary Diseases Department, Novartis Pharmaceuticals, Istanbul, TurkeyBackground: Low adherence to Global initiative for chronic Obstructive Lung Disease (GOLD) guideline recommendations has been reported worldwide. There has been no study on the adherence to GOLD guidelines for COPD treatment in Turkey.Objectives: To investigate the rates of adherence to GOLD 2010 guidelines for COPD treatment among pulmonologists.Design: A multi-center, cross-sectional, observational study was carried out in eleven pulmonary outpatient clinics across Turkey. Adherence to GOLD was evaluated through hospital records. Demographic and clinical data were recorded.Results: Study included 719 patients (mean age: 62.9±9.7 years; males 85.4%) of whom 16 was classified as GOLD Stage I, 238 as II, 346 as III, and 119 as IV, and only 59.5% received appropriate treatment. Rates of guideline adherence varied across GOLD stages (I, 6.3%; II, 14.7%; III, 84.4%; and IV, 84%). Causes of inappropriate therapies were overtreatment (Stage I, 100% and Stage II, 91.1%), undertreatment (Stage III, 3.3% and Stage IV, 10.9%) and lack of treatment (Stage II, 3.8%; Stage III, 2.3%; and Stage IV, 5.9%). The most preferred regimen (43.4%) was long-acting β2-agonist-inhaled corticosteroid-long-acting muscarinic antagonist. Overall, 614 patients (89%) received treatment containing inhaled corticosteroid.Conclusion: Pulmonologists in Turkey have low rates of adherence to GOLD guidelines in COPD treatment. Inappropriateness of therapies was due to overtreatment in early stages and excessive use of inhaled corticosteroid (ICS) in all disease stages.Keywords: adherence, COPD, Global initiative for chronic Obstructive Lung Disease guidelines, treatment approach, Turkey, overtreatment, inhaled corticosteroid
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- 2015
37. Consistency of Friedewald, Martin/Hopkins and Samson formulas for LDL-C calculation in high and very high cardiovascular risk patients
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Basaran, O., primary, Dogan, V., additional, Celik, O., additional, Cil, C., additional, Ozlek, B., additional, Ozlek, E., additional, Ozdemir, I.H., additional, Rencuzogullari, I., additional, Karadeniz, F., additional, Tekinalp, M., additional, Askin, L., additional, Demirelli, S., additional, Gencer, E., additional, Biteker, M., additional, and Kayikcioglu, M., additional
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- 2022
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38. Role of endometrial concentrations of heavy metals (cadmium, lead, mercury and arsenic) in the aetiology of unexplained infertility
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Tanrıkut, E., Karaer, A., Celik, O., Celik, E., Otlu, B., Yilmaz, E., and Ozgul, O.
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- 2014
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39. Predictive value of pre‐operative inflammation‐based prognostic scores (neutrophil‐to‐lymphocyte ratio, platelet‐to‐lymphocyte ratio, and monocyte‐to‐eosinophil ratio) in testicular sperm extraction: a pilot study
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Yucel, C., Keskin, M. Z., Cakmak, O., Ergani, B., Kose, C., Celik, O., Islamoglu, E., Ucar, M., Koc, G., and Kozacioglu, Z.
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- 2017
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40. Whipple telescope observations of LS I +61 303: 2004–2006
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Smith, A., Atkins, R. W., Bradbury, S., Celik, O., Chow, Y. C. K., Cogan, P., Dowdall, C., Fegan, S. J., Fortin, P., Gall, D., Gillanders, G. H., Grube, J., Gutierrez, K. J., Hall, T. A., Hanna, D., Holder, J., Horan, D., Hughes, S. B., Humensky, T. B., Jung, I., Kaaret, P., Kenny, G., Kertzman, M., Kieda, D. B., Konopelko, A., Krawczynski, H., Krennrich, F., Lang, M. J., Le Bohec, S., Maier, G., Millis, J., Moriarty, P., Ong, R. A., Perkins, J. S., Ragan, K., Sembroski, G. H., Toner, J. A., Valcarcel, L., Vassiliev, V. V., Wagner, R. G., Wakely, S. P., Weekes, T. C., White, R. J., Williams, D. A., Paredes, Josep M., editor, Reimer, Olaf, editor, and Torres, Diego F., editor
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- 2007
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41. Ultrasound Intensity and Treatment Time Fuzzy Logic Control System for Low Cost Effective Ultrasound Therapy Devices
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Yardimci, A., Celik, O., Kacprzyk, Janusz, editor, and Reusch, Bernd, editor
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- 2005
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42. CONSISTENCY OF FRIEDEWALD, MARTIN/HOPKINS AND SAMSON FORMULAS FOR LDL-C CALCULATION IN HIGH AND VERY HIGH CARDIOVASCULAR RISK PATIENTS
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Basaran, O., Dogan, V., Celik, O., Cil, C., Ozlek, B., Ozlek, E., and Ozdemir, I. H.
- Abstract
[No Abstract Available]
- Published
- 2022
43. Observed Beam-Column Joint Failures During 17 August 1999 Kocaeli and 12 November 1999 Duzce, Turkey Earthquakes
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Çelİk, O. C., Baniotopoulos, C. C., editor, and Wald, F., editor
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- 2000
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44. Diagnostic performance of two ultrasound techniques for the detection of cleft palate without cleft lip: axial-transverse and equal sign.
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CELIK, O. Y., BUCAK, M., SAGLAM, E., KAHRAMAN, N. C., KAYMAK, A. O., ARAT, O., IBANOGLU, M., İLHAN, T. T., ERGUN, E., CELEN, S., and ISKENDER, C.
- Abstract
OBJECTIVE: There is no study that compares the diagnostic performance of ATV and ESV techniques in detecting cleft palate. We aimed to evaluate the diagnostic accuracy of two ultrasound techniques: axial-transverse (ATV) and "equal sign" view (ESV), in detecting fetal cleft palate without cleft lip. PATIENTS AND METHODS: This prospective study was conducted from March 2019 to January 2022 in a tertiary referral hospital. Secondary palates were assessed with ATV and ESV by two experienced fetal medicine specialists who were blinded to each other's ultrasound findings. Final diagnosis was done according to postnatal physical examination. The sensitivity and specificity of the two techniques were calculated. RESULTS: A total of 311 pregnancies which met the study criteria were evaluated. Postnatal physical examination showed that 13 (0.4%) neonates had cleft palate only (CPO). According to final diagnosis the sensitivity, specificity, positive predictive value and negative predictive value for ATV were 100%, 98.7%, 76.4%, 100% and 100% for ESV were 76.9%, 97.8%, 58.9% and 99%, respectively. CONCLUSIONS: ATV in 2D ultrasound provides higher sensitivity and specificity than ESV in detecting CPO. [ABSTRACT FROM AUTHOR]
- Published
- 2023
45. Appropriateness of aspirin use among diabetic patients in primary prevention of atherosclerotic cardiovascular diseases: an analysis of the ASSOS study.
- Author
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DEMIRCI, E., CELIK, O., CIL, C., TANIK, V. O., SANCAR, K. MEMIC, ORSCELIK, O., RESULZADE, M. M., KAYA, C., KIRIS, T., DOGAN, V., and BASARAN, O.
- Abstract
OBJECTIVE: Aspirin is an essential drug in the prevention of atherosclerotic cardiovascular disease (ASCVD). It is ultimately indicated in a patient with ASCVD. However, its role is debated in primary prevention. We aimed to investigate the appropriateness of aspirin use in diabetic patients according to recommendations of recent guidelines. PATIENTS AND METHODS: ASSOS was a multicenter observational study investigating aspirin use in cardiology outpatient clinics. We evaluated aspirin use in diabetic patients in primary prevention from the ASSOS study. We also assessed the appropriate use of aspirin according to the European Society of Cardiology (ESC), American College of Cardiology/American Heart Association (ACC/AHA), American Diabetes Association (ADA), Consensus Statement of Endocrinology, Cardiology, and Nephrology (ENCARNE), and the United States Preventive Services Task Force (USPTF). RESULTS: A total of 5,007 patients of whom 1,537 had type 2 diabetes mellitus (DM) were included in the study. 1,132 of the total participants used aspirin for primary prevention; 313 of them had type 2 DM. Only 248 (76.7%), 132 (40.8%), and 128 (39.6%) diabetic patients indicated aspirin use according to the ESC/INCARNE, ACC/AHA, and ADA/USPTF guidelines, respectively. CONCLUSIONS: Inappropriate aspirin use was common among diabetic patients, according to clinical practice guideline recommendations. In addition, the differences between the indications for the use of aspirin in diabetic patients according to the guidelines were remarkable. Guidelines that minimize these differences are needed for clinicians, and compliance with these guidelines in clinical practice could reduce inappropriate aspirin use. [ABSTRACT FROM AUTHOR]
- Published
- 2023
46. Effect of pelvic lymph node dissection and its extent on oncological outcomes in intermediate-risk prostate cancer patients: A multicenter study of the Turkish Urooncology Association
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Izol, V., primary, Ok, F., additional, Aslan, G., additional, Akdogan, B., additional, Sozen, S., additional, Ozden, E., additional, Celik, O., additional, Muezzinoglu, T., additional, Turkeri, L., additional, Akdogan, N., additional, and Baltaci, S., additional
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- 2022
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47. High BNP level as risk factor for acute kidney injury and predictor of all-cause mortality in STEMI patients
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Akgul, O., Uyarel, H., Pusuroglu, H., Isiksacan, N., Turen, S., Erturk, M., Surgit, O., Celik, O., Oner, E., Birant, A., Akturk, I.F., and Uslu, N.
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- 2014
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48. Comparison of immunohistochemical characteristics of endometriomas with non-endometriotic benign ovarian cysts.
- Author
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CAGIRAN, F. T., KALI, Z., KIRICI, P., and CELIK, O.
- Abstract
OBJECTIVE: The aim of the study was to investigate the existence of neuroendocrine cells and to compare the density of those in normal ovarian tissue, endometriotic and non-endometriotic benign ovarian cysts. PATIENTS AND METHODS: Twenty patients with the diagnosis of endometrioma and 30 control subjects consisting of ovarian serous cystadenoma (n=10), ovarian mucinous cystadenoma (n=10) and normal ovarian tissue (n=10) were included. The tissues were prepared and assessed according to staining density by using the H-score method. RESULTS: Tissues with mucinous cystadenoma were significantly more stained with PAS and VanGieson, when compared to women with endometrioma. Macrophage deposition was higher in cyst samples with endometrioma and in normal ovarian tissue when compared to serous cystadenoma and mucinous cystadenoma. Normal ovarian tissue was significantly more stained with PGP9.5, NSE and SYN when compared to endometrioma and non-endometriotic benign ovarian cyst. PGP9.5 staining was higher in normal ovarian tissue when compared with endometriotic lesions (p<.001). Endometrioma samples were significantly more stained with p53 when compared to non-endometriotic cysts and normal ovarian tissue. c-Kit staining was mild and not statistically significant among all groups. CONCLUSIONS: During endometrioma transformation, expression intensity of neuroendocrine markers decreases compared to normal ovarian tissue and other benign ovarian cysts. [ABSTRACT FROM AUTHOR]
- Published
- 2022
49. Damage detection of a bridge model based on strain modal analysis
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Wang, T, primary, Catbas, F, additional, and Celik, O, additional
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- 2014
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50. No association of anti-osteoporosis drugs with COVID-19-related outcomes in women: a nationwide cohort study
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Atmaca, A., primary, Demirci, I., additional, Haymana, C., additional, Tasci, I., additional, Sahin, I., additional, Cakal, E., additional, Ata, N., additional, Dagdelen, S., additional, Salman, S., additional, Emral, R., additional, Sahin, M., additional, Celik, O., additional, Demir, T., additional, Ertugrul, D., additional, Unluturk, U., additional, Caglayan, M., additional, Satman, I., additional, and Sonmez, A., additional
- Published
- 2021
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- View/download PDF
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