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99 results on '"O'Brien M. S."'

1. Constraining the Evolution of ZZ Ceti

Author

Mukadam A. S., Kepler S. O., Winget D. E., Nather R. E., Kilic M., Mullally F., Hippel T. von, Kleinman S. J., Nitta A., Guzik J. A., Bradley P. A., Matthews J., Sekiguchi K., Sullivan D. J., Shobbrook R. R., Birch P., Jiang X. J., Xu D. W., Joshi S., Ashoka B.N., Ibbetson P., Leibowitz E., Ofek E. O., Meištas E. G., Janulis R., Ališauskas D., Kalytis R., Handler G., Kilkenny D., O’Donoghue D., Kurtz D. W., Müller M., Moskalik P., Ogłoza W., Zoła S., Krzesiński J., Johannessen F., Gonzalez-Perez J. M., Solheim J-E., Silvotti R., Bernabei S., Vauclair G., Dolez N., Fu J. N., Chevreton M., Manteiga M., Súarez O., Ulla A., Cunha M. S., Metcalfe T. S., Kanaan A., Fraga L., Costa A. F. M., Giovannini O., Fontaine G., Bergeron P., O’Brien M. S., Sanwal D., Wood M. A., Ahrens T. J., Silvestri N., Klumpe E. W., Kawaler S. D., Riddle R., Reed M. D., and Watson T. K.

Subjects
stars, white dwarfs, individual, ZZ Cet, R548 - stars, pulsations, evolution, Astronomy, QB1-991
Abstract

We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. Based on observations that span 31 years, we conclude that the period 213.132605 s observed in ZZ Ceti drifts at a rate dP/dt≤(5.5±1.9)×10−15 s/s, after correcting for proper motion. Our results are consistent with previous Ṗ values for this mode and an improvement over them due to the larger time-base. The characteristic stability timescale implied for the pulsation period is |P/ Ṗ|≥1.2 Gyr, comparable to the theoretical cooling timescale for the star. Our current stability limit for the period 213.132605 s is only slightly less than the present measurement for G117-B15A for the period 215.2 s, another DAV, establishing this mode in ZZ Ceti as the second most stable optical clock known, more stable than atomic clocks and most pulsars.

Published
2003
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4. The Intermediate Polar PQ Gem - Status of WET Observations of 1996

Author

Marar Τ. Μ. K., Seetha S., Ashoka B. N., Kasturirangan K., Mahra H. S., Bhattacharyya J. C., Leibowitz Ε. M., Hemar S., Mendelson H., Ibbetson P. A., O’Donoghue D., Buckley D. A. H., Βreger M., Handler G., Sperl M., Serkowitsch E., Reegen P., Moskalik P., Zola S., Pajdosz G., Krzesinski J., Silvotti R., Vauclair G., Dolez N., Solheim J. E., Pfeiffer B., Kepler S. O., Kanaan A., Provencal J., Kawaler S. D., O'Brien M. S., Nather R. E., Winget D. E., Kleinman S., Nitta A., Bradley P. A., Guzik J. A., Clemens C., Sullivan D. J., and Jiang X.

Subjects
Astronomy, QB1-991
Published
1998
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7. Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058-5234

Author

WET Collaboration, Sullivan, D. J., Metcalfe, T. S., O'Donoghue, D., Winget, D. E., Kilkenny, D., van Wyk, F., Kanaan, A., Kepler, S. O., Nitta, A., Kawaler, S. D., Montgomery, M. H., Nather, R. E., O'Brien, M. S., Bischoff-Kim, A., Wood, M., Jiang, X. J., Leibowitz, E. M., Ibbetson, P., Zola, S., Krzesinski, J., Pajdosz, G., Vauclair, G., Dolez, N., and Chevreton, M.

Subjects
Astrophysics
Abstract

We present the analysis of a total of 177h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058-5234. The bulk of the observations (135h) were obtained during a WET campaign (XCOV15) in July 1997 that featured coordinated observing from 4 southern observatory sites over an 8-day period. The remaining data (42h) were obtained in June 2004 at Mt John Observatory in NZ over a one-week observing period. This work significantly extends the discovery observations of this low-amplitude (few percent) pulsator by increasing the number of detected frequencies from 8 to 18, and employs a simulation procedure to confirm the reality of these frequencies to a high level of significance (1 in 1000). The nature of the observed pulsation spectrum precludes identification of unique pulsation mode properties using any clearly discernable trends. However, we have used a global modelling procedure employing genetic algorithm techniques to identify the n, l values of 8 pulsation modes, and thereby obtain asteroseismic measurements of several model parameters, including the stellar mass (0.55 M_sun) and T_eff (~28200 K). These values are consistent with those derived from published spectral fitting: T_eff ~ 28400 K and log g ~ 7.86. We also present persuasive evidence from apparent rotational mode splitting for two of the modes that indicates this compact object is a relatively rapid rotator with a period of 2h. In direct analogy with the corresponding properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude pulsation behaviour of EC 20058 is entirely consistent with its inferred effective temperature, which indicates it is close to the blue edge of the DBV instability strip. (abridged), Comment: 19 pages, 8 figures, 5 tables, MNRAS accepted

Published
2008
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8. The pulsation modes of the pre-white dwarf PG 1159-035

Author

Costa, J. E. S., Kepler, S. O., Winget, D. E., O'Brien, M. S., Kawaler, S. D., Costa, A. F. M., Giovannini, O., Kanaan, A., Mukadam, A. S., Mullally, F., Nitta, A., Provençal, J. L., Shipman, H., Wood, M. A., Ahrens, T. J., Grauer, A., Kilic, M., Bradley, P. A., Sekiguchi, K., Crowe, R., Jiang, X. J., Sullivan, D., Sullivan, T., Rosen, R., Clemens, J. C., Janulis, R., O'Donoghue, D., Ogloza, W., Baran, A., Silvotti, R., Marinoni, S., Vauclair, G., Dolez, N., Chevreton, M., Dreizler, S., Schuh, S., Deetjen, J., Nagel, T., Solheim, J. -E., Perez, J. M. Gonzalez, Ulla, A., Barstow, Martin, Burleigh, M., Good, S., Metcalfe, T. S., Kim, S. -L., Lee, H., Sergeev, A., Akan, M. C., Çakirli, Ö., Paparo, M., Viraghalmy, G., Ashoka, B. N., Handler, G., Hürkal, Özlem, Johannessen, F., Kleinman, S. J., Kalytis, R., Krzesinski, J., Klumpe, E., Larrison, J., Lawrence, T., Meištas, E., Martinez, P., Nather, R. E., Fu, J. -N., Pakštienė, E., Romero-Colmenero, E., Riddle, R., Seetha, S., Silvestri, N. M., Vučković, M., Warner, B., Zola, S., Althaus, L. G., Córsico, A. H., and Montgomery, M. H.

Subjects
Astrophysics
Abstract

PG 1159-035, a pre-white dwarf with T_eff=140,000 K, is the prototype of both two classes: the PG1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035 photometric data obtained with the Whole Earth Telescope (WET) showed a rich frequency spectrum allowing the identification of 122 pulsation modes. In this work, we used all available WET photometric data from 1983, 1985, 1989, 1993 and 2002 to identify the pulsation periods and identified 76 additional pulsation modes, increasing to 198 the number of known pulsation modes in PG 1159-035, the largest number of modes detected in any star besides the Sun. From the period spacing we estimated a mass M = 0.59 +/- 0.02 solar masses for PG 1159-035, with the uncertainty dominated by the models, not the observation. Deviations in the regular period spacing suggest that some of the pulsation modes are trapped, even though the star is a pre-white dwarf and the gravitational settling is ongoing. The position of the transition zone that causes the mode trapping was calculated at r_c = 0.83 +/- 0.05 stellar radius. From the multiplet splitting, we calculated the rotational period P_rot = 1.3920 +/- 0.0008 days and an upper limit for the magnetic field, B < 2000 G. The total power of the pulsation modes at the stellar surface changed less than 30% for l=1 modes and less than 50% for l=2 modes. We find no evidence of linear combinations between the 198 pulsation mode frequencies. PG 1159-035 models have not significative convection zones, supporting the hypothesis that nonlinearity arises in the convection zones in cooler pulsating white dwarf stars., Comment: 25 pages, 11 figures, appendix with 6 long tables. The resolution of some of the figures were changed and some of them can appear with a bit lower quality

Published
2007
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9. Period Stability on Pulsating White Dwarfs

Author

Kepler, S. O., Costa, J. E. S., Winget, D. E., Nather, R. E., Mukadam, Anjum, Nitta-Kleinman, A., O’Brien, M. S., de Martino, Domitilla, editor, Silvotti, Roberto, editor, Solheim, Jan-Erik, editor, and Kalytis, Romualdas, editor

Published
2003
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14. Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC20058-5234

Author

WET Collaboration, Sullivan, D. J., Metcalfe, T. S., O'Donoghue, D., Winget, D. E., Kilkenny, D., van Wyk, F., Kanaan, A., Kepler, S. O., Nitta, A., Kawaler, S. D., Montgomery, M. H., Nather, R. E., O'Brien, M. S., Bischoff-Kim, A., Wood, M., Jiang, X. J., Leibowitz, E. M., Ibbetson, P., Zola, S., Krzesinski, J., Pajdosz, G., Vauclair, G., Dolez, N., Chevreton, M., Brain imaging (LIAMA), Laboratoire Franco-Chinois d'Informatique, d'Automatique et de Mathématiques Appliquées (LIAMA), Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Chinese Academy of Sciences [Changchun Branch] (CAS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institute of Automation - Chinese Academy of Sciences-Centre National de la Recherche Scientifique (CNRS)-Centre de Coopération Internationale en Recherche Agronomique pour le Développement (Cirad)-Institut National de la Recherche Agronomique (INRA)-Chinese Academy of Sciences [Changchun Branch] (CAS)-Institut National de Recherche en Informatique et en Automatique (Inria)-Institute of Automation - Chinese Academy of Sciences-Centre National de la Recherche Scientifique (CNRS), Laboratoire Astrophysique de Toulouse-Tarbes (LATT), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire Midi-Pyrénées (OMP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
oscillations [stars], Stellar mass, FOS: Physical sciences, Astrophysics, Compact star, stars: interiors, 01 natural sciences, law.invention, Photometry (optics), Telescope, photometric [techniques], [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Análise asterosismológica, techniques: photometric, Observatory, law, 0103 physical sciences, Astrophysics::Solar and Stellar Astrophysics, 010303 astronomy & astrophysics, white dwarfs, Physics, interiors [stars], 010308 nuclear & particles physics, Estrelas ZZ Ceti, Astrophysics (astro-ph), White dwarf, Astronomy and Astrophysics, Effective temperature, stars: individual: EC 20058-5234, individual: EC 20058-5234 [stars], Fotometria astronômica, Anãs brancas, Pulsacoes estelares, 13. Climate action, Space and Planetary Science, stars: oscillations, Instability strip
Abstract

We present the analysis of a total of 177h of high-quality optical time-series photometry of the helium atmosphere pulsating white dwarf (DBV) EC 20058-5234. The bulk of the observations (135h) were obtained during a WET campaign (XCOV15) in July 1997 that featured coordinated observing from 4 southern observatory sites over an 8-day period. The remaining data (42h) were obtained in June 2004 at Mt John Observatory in NZ over a one-week observing period. This work significantly extends the discovery observations of this low-amplitude (few percent) pulsator by increasing the number of detected frequencies from 8 to 18, and employs a simulation procedure to confirm the reality of these frequencies to a high level of significance (1 in 1000). The nature of the observed pulsation spectrum precludes identification of unique pulsation mode properties using any clearly discernable trends. However, we have used a global modelling procedure employing genetic algorithm techniques to identify the n, l values of 8 pulsation modes, and thereby obtain asteroseismic measurements of several model parameters, including the stellar mass (0.55 M_sun) and T_eff (~28200 K). These values are consistent with those derived from published spectral fitting: T_eff ~ 28400 K and log g ~ 7.86. We also present persuasive evidence from apparent rotational mode splitting for two of the modes that indicates this compact object is a relatively rapid rotator with a period of 2h. In direct analogy with the corresponding properties of the hydrogen (DAV) atmosphere pulsators, the stable low-amplitude pulsation behaviour of EC 20058 is entirely consistent with its inferred effective temperature, which indicates it is close to the blue edge of the DBV instability strip. (abridged), 19 pages, 8 figures, 5 tables, MNRAS accepted

Published
2008

15. Abell 43 and PG 0122+200: a Look at the Beginning and at the End of the PG 1159 Instability Strip

Author

Vauclair, Gérard, Solheim, J.-E., Fu, J.-N., Chevreton, Michel, Dolez, N., O'Brien, M. S., Mukadam, Anjum S., Kim, S.-L., Park, B.-G., Handler, Gerald, Medupe, R., Wood, M., González Perez, J., Hashimoto, O., Kinugasa, K., Taguchi, H., Kambe, Eiji, Dobrovolskas, V., Provençal, J. L., Dreizler, Stefan, Schuh, S., Leibowitz, E. M., Lipkin, Y., Zhang, X.-B., Paparó, M., Szeidl, B., Viraghalmy, G., Zsuffa, D., Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA), Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), Pôle Astronomie du LESIA, and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris

Subjects
[PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph]
Abstract

International audience

Published
2006

16. PG 1605+ 072 in WET XCoV22: Support for the multi site spectroscopic telescope

Author

Nitta, A., Giovannini, O., Kawaler, S. D., Handler, G., Monteiro, H., Burleigh, M., Good, S., Kim, S.-L., Kilic, M., Rosen, R., Lee, H., Falter, S., Woolf, V. M., Schuh, S. L., Cakirli, Ö., Østensen, R., Shipman, H., Metcalfe, T. S., Grauer, A., Ulla, A., Vauclair, G., Sergeev, A., Kanaan, A., Bradley, P. A., Nagel, T., Xiaojun, J., da Costa, A. F. M., Kepler, S. O., Solheim, J.-E., Klumpe, E. W., Silvotti, R., Mukadam, A., Riddle, R. L., Mullally, F., Deetjen, J. L., Chevreton, M., Zoa, S., Wood, M. A., Dolez, N., González Pérez, J. M., Pakštiene, E., Akan, C., Provencal, J. L., Laurance, T., Jeffery, C. S., Sekiguchi, K., O'Toole, S., Ogloza, W., Crowe, R., Viraghalmy, G., Hürkal, Ö., Heber, U., Janulis, R., Baran, A., O'Donoghue, D., Dreizler, S., Sullivan, D. J., Costa, J. E. S., Marinoni, S., O'Brien, M. S., Vuckovic, M., Clemens, C., and Paparo, M.

Subjects
Astrophysics::Instrumentation and Methods for Astrophysics, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Cosmology and Extragalactic Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The Multi-site Spectroscopic Telescope is a virtual instrument and the name of a collaboration that opens up a new observational window by combining continuous observations of spectroscopic variations and simultaneous photometric monitoring. This constitutes an enormous observational effort, but in return promises to finally provide access to a mode identification for and an asteroseismological analysis of the pulsating sdB star PG 1605+072. Multi-Site Spectroscopic Telescope observations for this object have been secured during a large coordinated campaign in May and June of the year 2002. The frequency resolution and coverage of the photometric time series has been noticeably enhanced by a significant contribution from the Whole Earth Telescope, which was used to observe PG 1605+072 as an alternate target during the WET XCov22 campaign, also conducted in May 2002. This paper briefly outlines the motivation for the MSST project and tries to give a first assessment of the overall quality of the data obtained, with a focus on the Whole Earth Telescope observations.

Published
2003
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17. Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star

Author

Nather, R. E., Hansen, C. J., Barstow, M., Jiang, S. Y., Chernyshev, A. V., Chevreton, M., Pfeiffer, B., Clemens, J. C., Serre, B., Bruvold, A., Yanagida, K., Wood, M. A., Dolez, N., Winget, D. E., Provencal, J., Nitta Kleinman, A., Meistas, E. G., Hemar, S., Sansom, A. E., Kawaler, S. D., Watson, T. K., Krzesinski, J., Dixson, J. S., Klumpe, E. W., Pajdosz, G., Belmonte, J. A., Marar, T. M.K., Vauclair, G., Solheim, J. E., Grauer, A. D., Bradley, P. A., Zola, S., Moskalik, P., Kanaan, A., Kleinman, S. J., Giovannini, O., Kepler, S. O., Fu, J. N., Mazeh, T., Leibowitz, E., Ashoka, B. N., O'Brien, M. S., Achilleos, N., and Montgomery, M.

Subjects
Astrophysics::High Energy Astrophysical Phenomena, Astrophysics::Solar and Stellar Astrophysics, Astrophysics::Earth and Planetary Astrophysics, Astrophysics::Galaxy Astrophysics
Abstract

The pulsating PG 1159 planetary nebula central star RXJ 2117+3412 has been observed over three successive seasons of a multisite photometric campaign. The asteroseismological analysis of the data, based on the 37 identified

Published
2002
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18. Spinal injuries in children: role of MR

Author

Davis, P C, Reisner, A, Hudgins, P A, Davis, W E, and O'Brien, M S

Subjects
Male, Adolescent, Contusions, Age Factors, Infant, Newborn, Infant, Hemorrhage, Magnetic Resonance Imaging, Spinal Cord, Child, Preschool, Journal Article, Humans, Female, Child, Spinal Cord Injuries, Retrospective Studies
Abstract

PURPOSE: To define the clinical and prognostic role of MR in a pediatric population with spinal cord injury. METHODS: Fifteen children underwent MR 12 hours to 2 months postinjury using decoupled surface coils and ventilator support as needed. MR was correlated retrospectively with clinical, CT, and radiographic findings. RESULTS: On MR, of seven children with spinal cord neurologic deficits, four had hemorrhagic contusions, one had nonhemorrhagic contusion, one had extensive infarction, and one revealed a normal cord. All had persistent deficits on hospital discharge. Eight without cord neurologic deficit revealed no cord lesions on MR; this group included two with epidural hematoma, four with ligamentous disruption, and two with bone compression. CONCLUSIONS: Children may have extensive cord contusion and/or infarction with minor, remote, or no fracture dislocation. Because both hemorrhagic and nonhemorrhagic cord lesions found on MR were associated with significant, persistent cord deficits, the authors conclude that MR provides a practical tool for diagnosis/prognosis in children with acute/subacute spinal injury.

Published
1993

19. An empirical model of the Earth's horizontal wind fields: HWM07

Author

Drob, D. P., primary, Emmert, J. T., additional, Crowley, G., additional, Picone, J. M., additional, Shepherd, G. G., additional, Skinner, W., additional, Hays, P., additional, Niciejewski, R. J., additional, Larsen, M., additional, She, C. Y., additional, Meriwether, J. W., additional, Hernandez, G., additional, Jarvis, M. J., additional, Sipler, D. P., additional, Tepley, C. A., additional, O'Brien, M. S., additional, Bowman, J. R., additional, Wu, Q., additional, Murayama, Y., additional, Kawamura, S., additional, Reid, I. M., additional, and Vincent, R. A., additional

Published
2008
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20. Whole Earth Telescope observations of the hot helium atmosphere pulsating white dwarf EC 20058−5234

Author

Sullivan, D. J., primary, Metcalfe, T. S., additional, O'Donoghue, D., additional, Winget, D. E., additional, Kilkenny, D., additional, van Wyk, F., additional, Kanaan, A., additional, Kepler, S. O., additional, Nitta, A., additional, Kawaler, S. D., additional, Montgomery, M. H., additional, Nather, R. E., additional, O'Brien, M. S., additional, Bischoff-Kim, A., additional, Wood, M., additional, Jiang, X. J., additional, Leibowitz, E. M., additional, Ibbetson, P., additional, Zola, S., additional, Krzesinski, J., additional, Pajdosz, G., additional, Vauclair, G., additional, Dolez, N., additional, and Chevreton, M., additional

Published
2008
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21. The pulsation modes of the pre-white dwarf PG 1159-035

Author

Costa, J. E. S., primary, Kepler, S. O., additional, Winget, D. E., additional, O'Brien, M. S., additional, Kawaler, S. D., additional, Costa, A. F. M., additional, Giovannini, O., additional, Kanaan, A., additional, Mukadam, A. S., additional, Mullally, F., additional, Nitta, A., additional, Provençal, J. L., additional, Shipman, H., additional, Wood, M. A., additional, Ahrens, T. J., additional, Grauer, A., additional, Kilic, M., additional, Bradley, P. A., additional, Sekiguchi, K., additional, Crowe, R., additional, Jiang, X. J., additional, Sullivan, D., additional, Sullivan, T., additional, Rosen, R., additional, Clemens, J. C., additional, Janulis, R., additional, O'Donoghue, D., additional, Ogloza, W., additional, Baran, A., additional, Silvotti, R., additional, Marinoni, S., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Dreizler, S., additional, Schuh, S., additional, Deetjen, J., additional, Nagel, T., additional, Solheim, J.-E., additional, Gonzalez Perez, J. M., additional, Ulla, A., additional, Barstow, M., additional, Burleigh, M., additional, Good, S., additional, Metcalfe, T. S., additional, Kim, S.-L., additional, Lee, H., additional, Sergeev, A., additional, Akan, M. C., additional, Çakırlı, Ö., additional, Paparo, M., additional, Viraghalmy, G., additional, Ashoka, B. N., additional, Handler, G., additional, Hürkal, Ö., additional, Johannessen, F., additional, Kleinman, S. J., additional, Kalytis, R., additional, Krzesinski, J., additional, Klumpe, E., additional, Larrison, J., additional, Lawrence, T., additional, Meištas, E., additional, Martinez, P., additional, Nather, R. E., additional, Fu, J.-N., additional, Pakštienė, E., additional, Romero-Colmenero, E., additional, Riddle, R., additional, Seetha, S., additional, Silvestri, N. M., additional, Vučković, M., additional, Warner, B., additional, Zola, S., additional, Althaus, L. G., additional, Córsico, A. H., additional, and Montgomery, M. H., additional

Published
2007
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22. Asteroseismology of the PG 1159 star PG 0122+200

Author

Fu, J.-N., primary, Vauclair, G., additional, Solheim, J.-E., additional, Chevreton, M., additional, Dolez, N., additional, O'Brien, M. S., additional, Kim, S.-L., additional, Park, B.-G., additional, Handler, G., additional, Medupe, R., additional, Wood, M., additional, Gonzalez Perez, J., additional, Hashimoto, O., additional, Kinugasa, K., additional, Taguchi, H., additional, Kambe, E., additional, Provencal, J., additional, Dreizler, S., additional, Schuh, S., additional, Leibowitz, E., additional, Lipkin, Y., additional, Zhang, X.-B., additional, Paparo, M., additional, Szeidl, B., additional, Virághalmy, G., additional, and Zsuffa, D., additional

Published
2007
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23. Whole Earth Telescope Observations of the Pulsating Subdwarf B Star PG 0014+067

Author

Vučković, M., primary, Kawaler, S. D., additional, O’Toole, S., additional, Csubry, Z., additional, Baran, A., additional, Zola, S., additional, Moskalik, P., additional, Klumpe, E. W., additional, Riddle, R., additional, O’Brien, M. S., additional, Mullally, F., additional, Wood, M. A., additional, Wilkat, V., additional, Zhou, A.‐Y., additional, Reed, M. D., additional, Terndrup, D. M., additional, Sullivan, D. J., additional, Kim, S.‐L., additional, Chen, W. P., additional, Chen, C.‐W., additional, Hsiao, W.‐S., additional, Sanchawala, K., additional, Lee, H.‐T., additional, Jiang, X. J., additional, Janulis, R., additional, Siwak, M., additional, Ogloza, W., additional, Paparo, M., additional, Bognar, Zs., additional, Sodor, A., additional, Handler, G., additional, Lorenz, D., additional, Steininger, B., additional, Silvotti, R., additional, Vauclair, G., additional, Oreiro, R., additional, Ostensen, R., additional, Bronowska, A., additional, Castanheira, B. G., additional, Kepler, S. O., additional, Fraga, L., additional, Shipman, H. L., additional, Provencal, J. L., additional, and Childers, D., additional

Published
2006
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24. Whole Earth telescope observations of the ZZ Ceti star HL Tau 76

Author

Dolez, N., primary, Vauclair, G., additional, Kleinman, S. J., additional, Chevreton, M., additional, Fu, J. N., additional, Solheim, J.-E., additional, González Perez, J. M., additional, Ulla, A., additional, Fraga, L., additional, Kanaan, A., additional, Reed, M., additional, Kawaler, S., additional, O'Brien, M. S., additional, Metcalfe, T. S., additional, Nather, R. E., additional, Sanwal, D., additional, Klumpe, E. W., additional, Mukadam, A., additional, Wood, M. A., additional, Ahrens, T. J., additional, Silvestri, N., additional, Sullivan, D., additional, Sullivan, T., additional, Jiang, X. J., additional, Xu, D. W., additional, Ashoka, B. N., additional, Leibowitz, E., additional, Ibbetson, P., additional, Ofek, E., additional, Kilkenny, D., additional, Meištas, E. G., additional, Alisauskas, D., additional, Janulis, R., additional, Kalytis, R., additional, Moskalik, P., additional, Zola, S., additional, Krzesinski, J., additional, Ogloza, W., additional, Handler, G., additional, Silvotti, R., additional, and Bernabei, S., additional

Published
2006
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25. DQ Herculis in Profile: Whole Earth Telescope Observations and Smoothed Particle Hydrodynamics Simulations of an Edge‐on Cataclysmic Variable System

Author

Wood, M. A., primary, Robertson, J. R., additional, Simpson, J. C., additional, Kawaler, S. D., additional, O’Brien, M. S., additional, Nather, R. E., additional, Winget, D. E., additional, Montgomery, M. H., additional, Metcalfe, T. S., additional, Jiang, X. J., additional, Leibowitz, E. M., additional, Ibbetson, P., additional, O’Donoghue, D., additional, Zola, S., additional, Krzesinski, J., additional, Pajdosz, G., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Sullivan, D. J., additional, Kanaan, A., additional, and Nitta, A., additional

Published
2005
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26. Whole Earth Telescope observations of BPM 37093: A seismological test of crystallization theory in white dwarfs

Author

Kanaan, A., primary, Nitta, A., additional, Winget, D. E., additional, Kepler, S. O., additional, Montgomery, M. H., additional, Metcalfe, T. S., additional, Oliveira, H., additional, Fraga, L., additional, da Costa, A. F. M., additional, Costa, J. E. S., additional, Castanheira, B. G., additional, Giovannini, O., additional, Nather, R. E., additional, Mukadam, A., additional, Kawaler, S. D., additional, O'Brien, M. S., additional, Reed, M. D., additional, Kleinman, S. J., additional, Provencal, J. L., additional, Watson, T. K., additional, Kilkenny, D., additional, Sullivan, D. J., additional, Sullivan, T., additional, Shobbrook, B., additional, Jiang, X. J., additional, Ashoka, B. N., additional, Seetha, S., additional, Leibowitz, E., additional, Ibbetson, P., additional, Mendelson, H., additional, Meištas, E. G., additional, Kalytis, R., additional, Ališauskas, D., additional, O'Donoghue, D., additional, Buckley, D., additional, Martinez, P., additional, van Wyk, F., additional, Stobie, R., additional, Marang, F., additional, van Zyl, L., additional, Ogloza, W., additional, Krzesinski, J., additional, Zola, S., additional, Moskalik, P., additional, Breger, M., additional, Stankov, A., additional, Silvotti, R., additional, Piccioni, A., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Deetjen, J., additional, Dreizler, S., additional, Schuh, S., additional, Gonzalez Perez, J. M., additional, Østensen, R., additional, Ulla, A., additional, Manteiga, M., additional, Suarez, O., additional, Burleigh, M. R., additional, and Barstow, M. A., additional

Published
2005
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27. Whole Earth Telescope observations of the pulsating hot white dwarf PG 1707+427

Author

Kawaler, S. D., primary, Potter, E. M., additional, Vučković, M., additional, Dind, Z. E., additional, O'Toole, S., additional, Clemens, J. C., additional, O'Brien, M. S., additional, Grauer, A. D., additional, Nather, R. E., additional, Moskalik, P. A., additional, Claver, C. F., additional, Fontaine, G., additional, Wesemael, F., additional, Bergeron, P., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Kleinman, S. J., additional, Watson, T. K., additional, Barstow, M. A., additional, Sansom, A. E., additional, Winget, D. E., additional, Kepler, S. O., additional, Kanaan, A., additional, Bradley, P. A., additional, Dixson, J., additional, Provencal, J., additional, and Bedding, T. R., additional

Published
2004
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28. Constraining the Evolution of ZZ Ceti

Author

Mukadam, Anjum S., primary, Kepler, S. O., additional, Winget, D. E., additional, Nather, R. E., additional, Kilic, M., additional, Mullally, F., additional, von Hippel, T., additional, Kleinman, S. J., additional, Nitta, A., additional, Guzik, J. A., additional, Bradley, P. A., additional, Matthews, J., additional, Sekiguchi, K., additional, Sullivan, D. J., additional, Sullivan, T., additional, Shobbrook, R. R., additional, Birch, P., additional, Jiang, X. J., additional, Xu, D. W., additional, Joshi, S., additional, Ashoka, B. N., additional, Ibbetson, P., additional, Leibowitz, E., additional, Ofek, E. O., additional, Meištas, E. G., additional, Janulis, R., additional, Ališauskas, D., additional, Kalytis, R., additional, Handler, G., additional, Kilkenny, D., additional, O’Donoghue, D., additional, Kurtz, D. W., additional, Muller, M., additional, Moskalik, P., additional, Ogłoza, W., additional, Zoła, S., additional, Krzesiński, J., additional, Johannessen, F., additional, Gonzalez‐Perez, J. M., additional, Solheim, J.‐E., additional, Silvotti, R., additional, Bernabei, S., additional, Vauclair, G., additional, Dolez, N., additional, Fu, J. N., additional, Chevreton, M., additional, Manteiga, M., additional, Suarez, O., additional, Ulla, A., additional, Cunha, M. S., additional, Metcalfe, T. S., additional, Kanaan, A., additional, Fraga, L., additional, Costa, A. F. M., additional, Giovannini, O., additional, Fontaine, G., additional, Bergeron, P., additional, O’Brien, M. S., additional, Sanwal, D., additional, Wood, M. A., additional, Ahrens, T. J., additional, Silvestri, N., additional, Klumpe, E. W., additional, Kawaler, S. D., additional, Riddle, R., additional, Reed, M. D., additional, and Watson, T. K., additional

Published
2003
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29. Asteroseismology of RXJ 2117+3412, the hottest pulsating PG 1159 star

Author

Vauclair, G., primary, Moskalik, P., additional, Pfeiffer, B., additional, Chevreton, M., additional, Dolez, N., additional, Serre, B., additional, Kleinman, S. J., additional, Barstow, M., additional, Sansom, A. E., additional, Solheim, J.-E., additional, Belmonte, J. A., additional, Kawaler, S. D., additional, Kepler, S. O., additional, Kanaan, A., additional, Giovannini, O., additional, Winget, D. E., additional, Watson, T. K., additional, Nather, R. E., additional, Clemens, J. C., additional, Provencal, J., additional, Dixson, J. S., additional, Yanagida, K., additional, Nitta Kleinman, A., additional, Montgomery, M., additional, Klumpe, E. W., additional, Bruvold, A., additional, O'Brien, M. S., additional, Hansen, C. J., additional, Grauer, A. D., additional, Bradley, P. A., additional, Wood, M. A., additional, Achilleos, N., additional, Jiang, S. Y., additional, Fu, J. N., additional, Marar, T. M. K., additional, Ashoka, B. N., additional, Meistas, E. G., additional, Chernyshev, A. V., additional, Mazeh, T., additional, Leibowitz, E., additional, Hemar, S., additional, Krzesiński, J., additional, Pajdosz, G., additional, and Zoła, S., additional

Published
2002
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30. The pulsation modes of the pre-white dwarf PG 1159-035*

Author

Costa, J. E. S., Kepler, S. O., Winget, D. E., O'Brien, M. S., Kawaler, S. D., Costa, A. F. M., Giovannini, O., Kanaan, A., Mukadam, A. S., Mullally, F., Nitta, A., Provençal, J. L., Shipman, H., Wood, M. A., Ahrens, T. J., Grauer, A., Kilic, M., Bradley, P. A., Sekiguchi, K., Crowe, R., Jiang, X. J., Sullivan, D., Sullivan, T., Rosen, R., Clemens, J. C., Janulis, R., O'Donoghue, D., Ogloza, W., Baran, A., Silvotti, R., Marinoni, S., Vauclair, G., Dolez, N., Chevreton, M., Dreizler, S., Schuh, S., Deetjen, J., Nagel, T., Solheim, J.-E., Gonzalez Perez, J. M., Ulla, A., Barstow, M., Burleigh, M., Good, S., Metcalfe, T. S., Kim, S.-L., Lee, H., Sergeev, A., Akan, M. C., Çakırlı, Ö., Paparo, M., Viraghalmy, G., Ashoka, B. N., Handler, G., Hürkal, Ö., Johannessen, F., Kleinman, S. J., Kalytis, R., Krzesinski, J., Klumpe, E., Larrison, J., Lawrence, T., Meištas, E., Martinez, P., Nather, R. E., Fu, J.-N., Pakštienė, E., Rosen, R., Romero-Colmenero, E., Riddle, R., Seetha, S., Silvestri, N. M., Vučković, M., Warner, B., Zola, S., Althaus, L. G., Córsico, A. H., Montgomery, M. H., Costa, J. E. S., Kepler, S. O., Winget, D. E., O'Brien, M. S., Kawaler, S. D., Costa, A. F. M., Giovannini, O., Kanaan, A., Mukadam, A. S., Mullally, F., Nitta, A., Provençal, J. L., Shipman, H., Wood, M. A., Ahrens, T. J., Grauer, A., Kilic, M., Bradley, P. A., Sekiguchi, K., Crowe, R., Jiang, X. J., Sullivan, D., Sullivan, T., Rosen, R., Clemens, J. C., Janulis, R., O'Donoghue, D., Ogloza, W., Baran, A., Silvotti, R., Marinoni, S., Vauclair, G., Dolez, N., Chevreton, M., Dreizler, S., Schuh, S., Deetjen, J., Nagel, T., Solheim, J.-E., Gonzalez Perez, J. M., Ulla, A., Barstow, M., Burleigh, M., Good, S., Metcalfe, T. S., Kim, S.-L., Lee, H., Sergeev, A., Akan, M. C., Çakırlı, Ö., Paparo, M., Viraghalmy, G., Ashoka, B. N., Handler, G., Hürkal, Ö., Johannessen, F., Kleinman, S. J., Kalytis, R., Krzesinski, J., Klumpe, E., Larrison, J., Lawrence, T., Meištas, E., Martinez, P., Nather, R. E., Fu, J.-N., Pakštienė, E., Rosen, R., Romero-Colmenero, E., Riddle, R., Seetha, S., Silvestri, N. M., Vučković, M., Warner, B., Zola, S., Althaus, L. G., Córsico, A. H., and Montgomery, M. H.

Abstract

Context.PG 1159-035, a pre-white dwarf with $T_{{\rm eff}}$$\simeq$140 000 K, is the prototype of both two classes: the PG 1159 spectroscopic class and the DOV pulsating class. Previous studies of PG 1159-035photometric data obtained with the Whole Earth Telescope (WET) showed a rich frequency spectrum allowing the identification of 122 pulsation modes. Analyzing the periods of pulsation, it is possible to measure the stellar mass, the rotational period and the inclination of the rotation axis, to estimate an upper limit for the magnetic field, and even to obtain information about the inner stratification of the star.

Published
2008
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32. Normal modes and discovery of high-order cross-frequencies in the DBV white dwarf GD 358

Author

Vuille, F., primary, O'Donoghue, D., additional, Buckley, D. A. H., additional, Massacand, C.- M., additional, Solheim, J. E., additional, Bard, S., additional, Vauclair, G., additional, Giovannini, O., additional, Kepler, S. O., additional, Kanaan, A., additional, Provencal, J. L., additional, Wood, M. A., additional, Clemens, J. C., additional, Kleinman, S. J., additional, O'Brien, M. S., additional, Nather, R. E., additional, Winget, D. E., additional, Nitta, A., additional, Klumpe, E. W., additional, Montgomery, M. H., additional, Watson, T. K., additional, Bradley, P. A., additional, Sullivan, D. J., additional, Wu, K., additional, Marar, T. M. K., additional, Seetha, S., additional, Ashoka, B. N., additional, Mahra, H. S., additional, Bhat, B. C., additional, Babu, V. C., additional, Leibowitz, E. M., additional, Hemar, S., additional, Ibbetson, P., additional, Mashals, E., additional, Mei tas, E., additional, Moskalik, P., additional, Zola, S., additional, Krzesinski, J., additional, and Pajdosz, G., additional

Published
2000
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35. Asteroseismology of a Star Cooled by Neutrino Emission: The Pulsating Pre–White Dwarf PG 0122+200

Author

O'Brien, M. S., primary, Vauclair, G., additional, Kawaler, S. D., additional, Watson, T. K., additional, Winget, D. E., additional, Nather, R. E., additional, Montgomery, M., additional, Nitta, A., additional, Kleinman, S. J., additional, Sullivan, D. J., additional, Jiang, X. J., additional, Marar, T. M. K., additional, Seetha, S., additional, Ashoka, B. N., additional, Bhattacharya, J., additional, Leibowitz, E. M., additional, Hemar, S., additional, Ibbetson, P., additional, Warner, B., additional, van Zyl, L., additional, Moskalik, P., additional, Zoła, S., additional, Pajdosz, G., additional, Krzesiński, J., additional, Dolez, N., additional, Chevreton, M., additional, Solheim, J.‐E., additional, Thomassen, T., additional, Kepler, S. O., additional, Giovannini, O., additional, Provencal, J. L., additional, Wood, M. A., additional, and Clemens, J. C., additional

Published
1998
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36. New Whole Earth Telescope observations of CD-24 7599: steps towards Scuti star seismology

Author

Handler, G., primary, Pikall, H., additional, O'Donoghue, D., additional, Buckley, D. A. H., additional, Vauclair, G., additional, Chevreton, M., additional, Giovannini, O., additional, Kepler, S. O., additional, Goode, P. R., additional, Provencal, J. L., additional, Wood, M. A., additional, Clemens, J. C., additional, O'Brien, M. S., additional, Nather, R. E., additional, Winget, D. E., additional, Kleinman, S. J., additional, Kanaan, A., additional, Watson, T. K., additional, Nitta, A., additional, Montgomery, M. H., additional, Klumpe, E. W., additional, Bradley, P. A., additional, Sullivan, D. J., additional, Wu, K., additional, Marar, T. M. K., additional, Seetha, S., additional, Ashoka, B. N., additional, Mahra, H. S., additional, Bhat, B. C., additional, Babu, V. C., additional, Leibowitz, E. M., additional, Hemar, S., additional, Ibbetson, P. A., additional, Mashal, E., additional, Meistas, E. G., additional, Dziembowski, W. A., additional, Pamyatnykh, A. A., additional, Moskalik, P., additional, Zola, S., additional, Pajdosz, G., additional, Krzesinski, J., additional, Solheim, J. E., additional, Bard, S., additional, Massacand, C. M., additional, Breger, M., additional, Gelbmann, M. J., additional, Paunzen, E., additional, and North, P., additional

Published
1997
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37. Whole Earth Telescope Observations and Seismological Analysis of the Pre--White Dwarf PG 2131+066

Author

Kawaler, S. D., primary, O'Brien, M. S., additional, Clemens, J. C., additional, Nather, R. E., additional, Winget, D. E., additional, Watson, T. K., additional, Yanagida, K., additional, Dixson, J. S., additional, Bradley, P. A., additional, Wood, M. A., additional, Sullivan, D. J., additional, Kleinman, S. J., additional, Meistas, E., additional, Leibowitz, E. M., additional, Moskalik, P., additional, Zola, S., additional, Pajdosz, G., additional, Krzesinski, J., additional, Solheim, J.-E., additional, Bruvold, A., additional, O'Donoghue, D., additional, Katz, M., additional, Vauclair, G., additional, Dolez, N., additional, Chevreton, M., additional, Barstow, M. A., additional, Kanaan, A., additional, Kepler, S. O., additional, Giovannini, O., additional, Provencal, J. L., additional, and Hansen, C. J., additional

Published
1995
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38. New WET Observations of the δ Scuti Star CD-24 7599: amplitude variability and discovery of 13 pulsation modes

Author

Handler, G., primary, O’Donoghue, D., additional, Buckley, D. A. H., additional, Giovannini, O., additional, Kepler, S. O., additional, Provencal, J. L., additional, Wood, M. A., additional, Clemens, J. C., additional, O’Brien, M. S., additional, Kleinman, S. J., additional, Watson, T. K., additional, Nather, R. E., additional, Winget, D. E., additional, Kanaan, A., additional, Nitta, A., additional, Montgomery, M. H., additional, Klumpe, E., additional, Bradley, P. A., additional, Sullivan, D. J., additional, Wu, K., additional, and Leibowitz, E., additional

Published
1995
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40. Effect of spironolactone on the renal clearance of digoxin in dogs.

Author

O'Brien, M S, Salamone, L F, and Gibson, T P

Abstract

The acute effect of i.v. spironolactone dissolved in ethanol on renal digoxin clearance was studied in 10 dogs. All dogs received i.v. digoxin (0.02 micrograms/kg/min) and 0.9% saline (30 ml/kg of bolus and 0.1 ml/kg/min for maintenance) throughout the study. After 2 hr of equilibration, four 15-min urine collections were made. The dogs then received, over 1 hr, a loading infusion of 4 mg/kg of spironolactone in ethanol (group 1, N = 6) or ethanol alone (group 2, N = 4). Thereafter the infusion was maintained at one-tenth the initial rate for eight 15-min periods. Three additional control dogs received ethanol plus spironolactone without digoxin. Digoxin radioimmunoassay of plasma and urine from these control animals did not reveal any significant cross-reactivity between spironolactone and the antibody of the digoxin radioimmunoassay. The digoxin clearance (CDIG) and ratio of CDIG to inulin clearance (CDIG/CIN) increased insignificantly with ethanol alone, but were respectively reduced by 21 and 28% with spironolactone (P less than .05). The reductions of CDIG and CDIG/CIN were observed immediately after the spironolactone loading infusion and were associated with a sudden rise in plasma digoxin. The changes in digoxin handling with spironolactone appeared to be temporally dissociated from the antimineralocorticoid activity of spironolactone. We conclude that spironolactone inhibits renal CDIG by a mechanism that may be independent of its antimineralocorticoid activity.

Published
1985

42. The Influence of Ratio and Allometric Scaling Procedures for Normalizing Upper Body Power Output in Division I Collegiate Football Players.

Author

Thompson, B J, Smith, D B, Jacobson, B H, Fiddler, R E, Warren, A J, Long, B C, O'Brien, M S, Everett, K L, Glass, R G, and Ryan, E D

Abstract

Upper body power output may be important for collegiate football players when involved in blocking or tackling opponents, however, differences in body size may potentially confound tests examining upper body power output. PURPOSE: To examine the differences in upper body power output among lineman and non-lineman Division I collegiate football players, and to examine the influence of two normalization procedures: (1) ratio scaling and (2) standardized allometric scaling. METHODS: Ten lineman (mean ± SD: age = 19.3 ± 1.6 years; height = 187.7 ± 4.7 cm; mass = 127.7 ± 13.3 kg) and 14 non-lineman (19.6 ± 1.4 years; 181.8 ± 5.2 cm; 92.3 ± 10.6 kg) performed a multiple repetition bench press power test at 50% of their 1 - repetition maximum (1 - RM). Peak power (PP) was determined from a Tendo Weightlifting Analyzer that was attached to the barbell. The PP values were then analyzed under 3 conditions that included: (1) no scaling (absolute values), (2) ratio scaling (PP · body mass-1), and (3) allometric scaling (PP · body mass-0.67). Independent samples t-tests were used to analyze differences in age, body mass, height, and all 3 PP conditions between the lineman and non-lineman groups. RESULTS: The results indicated that the linemen were larger and taller (P < 0.05) than the non-lineman with no differences in age (P = 0.96). The lineman demonstrated greater absolute PP values (P = 0.02); however, ratio scaling favored the smaller non-lineman group (P = 0.04). There were no differences in PP values between positions following the standardized allometric scaling procedure (P = 0.60). CONCLUSIONS: These findings indicated that the standardized allometric scaling procedure may be a more effective method for normalizing PP values among elite Division I collegiate football players. PRACTICAL APPLICATIONS: These findings may be useful for strength and conditioning coaches who are interested in comparing upper body PP among different player positions by utilizing the standardized allometric scaling technique that can be determined with many handheld calculators. [ABSTRACT FROM AUTHOR]

Published
2011
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44. Neurophysiological assessment of joint nociceptors in the rat medial meniscus transection model of post-traumatic osteoarthritis.

Author

O'Brien MS and McDougall JJ

Subjects
Animals, Disease Models, Animal, Electrodiagnosis, Female, Knee Joint innervation, Male, Menisci, Tibial surgery, Neural Conduction, Pain Measurement, Rats, Rats, Wistar, Sex Factors, Afferent Pathways physiopathology, Evoked Potentials physiology, Hyperalgesia physiopathology, Neuralgia physiopathology, Nociceptors physiology, Osteoarthritis, Knee physiopathology
Abstract

Objective: Meniscal injury is a common prelude to post-traumatic osteoarthritis (PTOA). Joint nerves can become damaged in arthritic joints leading to the manifestation of neuropathic pain. Both PTOA and neuropathic pain are more common in females; however, it is unknown whether the neural processing of joint pain is sex-specific., Design: Male and female Wistar rats (230-286g) underwent unilateral medial meniscus transection (MMT) and allowed to recover for 28 days. Pain development was assessed over the time course by von Frey hair algesiometry and dynamic weight bearing. Recordings from joint primary afferents was carried out by electrophysiology at end-stage disease. Nerve damage and β-endorphin levels were also compared between MMT and sham operated animals., Results: Male MMT rats exhibited significant pain behaviour compared to sham control. Evoked afferent firing rate was heightened in male MMT animals. Female PTOA rats did not show signs of pain behaviour on each of the test days and the neurophysiological properties of their nociceptors was not different from control. Peripheral neuropathy was observed in about 30% of axons from male MMT animals compared to 15% in females. Systemic β-endorphin levels in female PTOA rats was 91.0 ± 10.4 pg/mL and only 49.0 ± 5.0 pg/mL in males., Conclusions: Secondary allodynia and joint pain were observed in male but not female MMT rats. Joint nociceptors were sensitized in PTOA males but not in females. This lack of pain in females may be due to the absence of a peripheral neuropathy and greater endogenous opioid production., (Copyright © 2020 Osteoarthritis Research Society International. Published by Elsevier Ltd. All rights reserved.)

Published
2020
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45. Second stage of a genome scan of schizophrenia: study of five positive regions in an expanded sample.

Author

Mowry BJ, Ewen KR, Nancarrow DJ, Lennon DP, Nertney DA, Jones HL, O'Brien MS, Thornley CE, Walters MK, Crowe RR, Silverman JM, Endicott J, Sharpe L, Hayward NK, Gladis MM, Foote SJ, and Levinson DF

Subjects
Alleles, Chromosome Mapping, Chromosomes, Human, Pair 10 genetics, Chromosomes, Human, Pair 11 genetics, Chromosomes, Human, Pair 2 genetics, Chromosomes, Human, Pair 4 genetics, Chromosomes, Human, Pair 9 genetics, Family Health, Female, Gene Frequency, Genetic Linkage, Genotype, Humans, Male, Microsatellite Repeats, Software, Genome, Human, Schizophrenia genetics
Abstract

In a previous genome scan of 43 schizophrenia pedigrees, nonparametric linkage (NPL) scores with empirically derived pointwise P-values less than 0.01 were observed in two regions (chromosomes 2q12-13 and 10q23) and less than 0.05 in three regions (4q22-23, 9q22, and 11q21). Markers with a mean spacing of about 5 cM were typed in these regions in an expanded sample of 71 pedigrees, and NPL analyses carried out. No region produced significant genomewide evidence for linkage. On chromosome 10q, the empirical P-value remained at less than 0.01 for the entire sample (D10S168), evidence in the original 43 pedigrees was slightly increased, and a broad peak of positive results was observed. P-values less than 0.05 were observed on chromosomes 2q (D2S436) and 4q (D4S2623), but not on chromosomes 9q or 11q. It is concluded that this sample is most supportive of linkage on chromosome 10q, with less consistent support on chromosomes 2q and 4q. Am. J. Med. Genet. (Neuropsychiatr. Genet.) 96:864-869, 2000., (Copyright 2000 Wiley-Liss, Inc.)

Published
2000

46. Systematic approach for detection of endocrine disorders in children treated for brain tumors.

Author

Meacham LR, Ghim TT, Crocker IR, O'Brien MS, Petronio J, Davis P, Vogel BC, and Krawiecki NS

Subjects
Brain Neoplasms complications, Chemotherapy, Adjuvant adverse effects, Child, Humans, Radiotherapy adverse effects, Brain Neoplasms therapy, Endocrine System Diseases diagnosis, Endocrine System Diseases etiology
Abstract

Endocrine dysfunction can be challenging to diagnose in children treated for brain tumors. Treatments are available for hormonal replacement and when necessary, hormonal suppression. Without these endocrine treatment regimens, life can be unnecessarily difficult or unpleasant. An endocrine survey can be used to screen at-risk neuro-oncology patients once or twice a year to facilitate the recognition of endocrine dysfunction. It is hoped that through the use of a routine screening program, physicians will be able to diagnose and begin treatment of endocrine problems in a time-efficient manner.

Published
1997
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47. Decision making in primary surgical repair of myelomeningoceles.

Author

de Chalain TM, Cohen SR, Burstein FD, Hudgins RJ, Boydston WR, and O'Brien MS

Subjects
Decision Making, Female, Humans, Infant, Newborn, Logistic Models, Male, Retrospective Studies, Surgery, Plastic statistics & numerical data, Ventriculoperitoneal Shunt, Meningomyelocele surgery
Abstract

A 5-year review of 43 consecutive patients presenting to Scottish Rite Children's Medical Center with an open myelomeningocele defect was undertaken. The aim of the present study was to analyze the myelomeningocele defects, dimensions, and area to better define those factors that dictate the need for plastic surgical consultation for wound closure. Of the 43 patients identified, two were excluded because they first presented as older children; the remaining 41 all had their myelomeningoceles repaired within the first 36 hours of life. Of these, 31 underwent repair by the Neurosurgical Service, whereas for 10 patients (24.4%), the Plastic Surgery Service was asked to assist with closure. Comparison showed the mean (+/- standard deviation) area in the referred patients was 27.4 (7.6) cm2 versus 17.6 (7.9) cm2 in the patients not referred for closure (p = 0.002). A trend analysis predicting referral as a function of myelomeningocele area showed that 0 of 10 (0%) with an area of less than 15 cm2, 2 of 13 (15.4%) with an area equal to 15 to 20 cm2, 3 of 7 (42.9%) with an area of 21 to 25 cm2, and 4 of 9 (44%) with an area greater than 25 cm2 were referred (p = 0.001). Data from the interpretation of maximum myelomeningocele dimension also showed statistically significant trends in referral. Using multiple logistic regression, it was found that the odds of referral increased by a factor of 3.3 for every 1 cm increase in maximum dimension.

Published
1995
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48. Delayed intracranial hemorrhage in children after suboccipital craniectomy.

Author

Nixon KT, Hudgins PA, Davis PC, O'Brien MS, Hudgins RJ, and Hoffman JC Jr

Subjects
Brain Neoplasms surgery, Cerebral Hemorrhage diagnosis, Cerebral Hemorrhage epidemiology, Child, Craniocerebral Trauma complications, Dura Mater surgery, Female, Humans, Magnetic Resonance Imaging, Male, Postoperative Complications epidemiology, Postoperative Complications etiology, Retrospective Studies, Time Factors, Tomography, X-Ray Computed, Cerebral Hemorrhage etiology, Cranial Fossa, Posterior surgery, Postoperative Complications diagnosis, Prostheses and Implants adverse effects, Silicone Elastomers adverse effects
Abstract

Objective: The purpose of this study was to report the clinical and imaging findings of seven children who developed extraaxial, intracranial hemorrhage 3-12 years after suboccipital craniectomy for neoplasia. We attempt to explain the hemorrhages based on a previously reported hypothesis of neomembrane formation associated with dural substitutes used to repair large dural defects., Materials and Methods: Clinical charts (seven patients), surgical and pathologic findings (four patients), and imaging studies (CT scans and MR images in four; CT scans, MR images, and angiograms in one; and CT scans only in two patients) were reviewed retrospectively. Hemorrhage occurred 3-12 years after suboccipital craniectomy for tumor (ependymoma in two, medulloblastoma in three, astrocytoma in one, and ganglioglioma in one). Silastic dural substitute was used to repair the surgical wound in six cases and human dural graft in one case. Hematomas were spontaneous in four and occurred after minor head trauma in three. Four patients had multiple hemorrhagic episodes., Results: CT scans and MR images showed acute extraaxial hemorrhages at the craniectomy site without contiguous residual or recurrent neoplasia in all patients. No intraaxial or intratumoral hemorrhage was detected. Findings on cerebral angiograms in one patient were normal. Four patients underwent surgical exploration of the hematoma and craniectomy site; no macroscopic source of bleeding was detected. The hematomas were not associated with recurrent tumor pathologically., Conclusion: Delayed, benign extraaxial hematomas may occur in children who have undergone craniectomy for tumors of the posterior fossa and have had dural substitute used to repair large defects. Fragile vessels associated with nonmembranes have been proposed as the source of hemorrhage.

Published
1994
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49. Carotid endarterectomy for non-hemispheric ischaemia: long-term follow-up.

Author

Ricotta JJ, O'Brien MS, and DeWeese JA

Subjects
Aged, Carotid Stenosis pathology, Carotid Stenosis surgery, Cerebrovascular Disorders etiology, Cohort Studies, Disease-Free Survival, Female, Follow-Up Studies, Humans, Life Tables, Longitudinal Studies, Male, New York epidemiology, Recurrence, Risk Factors, Survival Rate, Vertebral Artery pathology, Brain Ischemia surgery, Endarterectomy, Carotid mortality, Endarterectomy, Carotid statistics & numerical data
Abstract

Earlier results reported by the authors suggest that carotid endarterectomy can relieve symptoms of non-hemispheric ischemia in patients who present with hemodynamically significant carotid stenosis. Long-term follow-up of a subgroup of these patients is described. Some 61 patients with non-hemispheric ischemia who underwent carotid endarterectomy were reviewed. Indications for surgery and postoperative results (stroke, death, symptom relief) were determined by office visit or phone interview. Results in these patients were compared with those of an entire patient population who underwent endarterectomy performed by the authors. Mean (s.d.) follow-up was available for 42.3 (31.7) months. Perioperative stroke rate (4.9%), survival (85.3 and 64.9% at 3 and 5 years respectively) and stroke-free survival (77.1 and 63.4% at 3 and 5 years respectively) were not different from that entire cohort of 553 patients. During follow-up, 11 patients (18%) developed recurrent symptoms of non-hemispheric ischemia. Carotid endarterectomy is successful in providing long-term relief of symptoms of non-hemispheric ischemia in most patients with significant carotid bifurcation stenosis. Results in such patients are similar to those seen in patients with symptoms of anterior cerebral ischemia or with symptom-free stenoses.

Published
1994

50. Postoperative treatment of patients undergoing carotid endarterectomy.

Author

O'Brien MS and Ricotta JJ

Subjects
Critical Care, Endarterectomy adverse effects, Humans, Carotid Stenosis surgery, Endarterectomy nursing, Postoperative Care methods
Abstract

Carotid endarterectomy is a common procedure aimed at the prevention of cerebral vascular accident. Death after carotid endarterectomy is rare (approximately 1%). Postoperative complications occur infrequently (3% to 5%). Myocardial infarction and cerebral vascular accident, two of the most serious postoperative complications, are often associated with changes in blood pressure that occur early in the postoperative period. In addition, cerebral vascular accident often results from thrombosis at the operative site, which may occur during the operation or in the early perioperative phase. Therefore intense monitoring of neurologic and hemodynamic status during the early postoperative period is advocated to control blood pressure and detect changes in neurologic condition. Traditionally, this care is provided in an intensive care unit. Current studies suggest that more than 80% of patients who undergo carotid endarterectomy do not use unique intensive care unit resources; rather, they require monitoring services, which can be safely provided in less intensive alternate settings. This article provides an overview of carotid endarterectomy. Postoperative complications and early (24-hour) perioperative management are reviewed. Alternative strategies to intensive care unit monitoring are proposed.

Published
1994

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