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1. Hemispherical differences in the shape and topography of asteroid (101955) Bennu

Author

M. G. Daly, O. S. Barnouin, J. A. Seabrook, J. Roberts, C. Dickinson, K. J. Walsh, E. R. Jawin, E. E. Palmer, R. Gaskell, J. Weirich, T. Haltigin, D. Gaudreau, C. Brunet, G. Cunningham, P. Michel, Y. Zhang, R.-L. Ballouz, G. Neumann, M. E. Perry, L. Philpott, M. M. Al Asad, C. L. Johnson, C. D. Adam, J. M. Leonard, J. L. Geeraert, K. Getzandanner, M. C. Nolan, R. T. Daly, E. B. Bierhaus, E. Mazarico, B. Rozitis, A. J. Ryan, D. N. DellaGiustina, B. Rizk, H. C. M. Susorney, H. L. Enos, and D. S. Lauretta

Subjects
Space Sciences (General)
Abstract

We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu's southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu's history.

Published
2020
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2. The unexpected surface of asteroid (101955) Bennu

Author

D. S. Lauretta, D. N. DellaGiustina, C. A. Bennett, D. R. Golish, K. J. Becker, S. S. Balram-Knutson, O. S. Barnouin, T. L. Becker, W. F. Bottke, W. V. Boynton, H. Campins, H. C. Connolly Jr, C. Y. Drouet d’Aubigny, J. P. Dworkin, J. P. Emery, H. L. Enos, V. E. Hamilton, C. W. Hergenrother, E. S. Howell, M. R. M. Izawa, H. H. Kaplan, M. C. Nolan, B. Rizk, H. L. Roper, D. J. Scheeres, P. H. Smith, K. J. Walsh, C. W. V. Wolner, D. E. Highsmith, J. Small, D. Vokrouhlický, N. E. Bowles, E. Brown, K. L. Donaldson Hanna, T. Warren, C. Brunet, R. A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D. L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C. M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, L. McGraw, R. Ghent, R. P. Binzel, M. M. Al Asad, C. L. Johnson, L. Philpott, H. C. M. Susorney, E. A. Cloutis, R. D. Hanna, F. Ciceri, A. R. Hildebrand, E.-M. Ibrahim, L. Breitenfeld, T. Glotch, A. D. Rogers, B. E. Clark, S. Ferrone, C. A. Thomas, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J. R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M. K. Crombie, C. Lantz, J. de Leon, J. Licandro, J. L. Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal, M. Yoshikawa, J. Bellerose, S. Bhaskaran, C. Boyles, S. R. Chesley, C. M. Elder, D. Farnocchia, A. Harbison, B. Kennedy, A. Knight, N. Martinez-Vlasoff, N. Mastrodemos, T. McElrath, W. Owen, R. Park, B. Rush, L. Swanson, Y. Takahashi, D. Velez, K. Yetter, C. Thayer, C. Adam, P. Antreasian, J. Bauman, C. Bryan, B. Carcich, M. Corvin, J. Geeraert, J. Hoffman, J. M. Leonard, E. Lessac-Chenen, A. Levine, J. McAdams, L. McCarthy, D. Nelson, B. Page, J. Pelgrift, E. Sahr, K. Stakkestad, D. Stanbridge, D. Wibben, B. Williams, K. Williams, P. Wolff, P. Hayne, D. Kubitschek, M. A. Barucci, J. D. P. Deshapriya, S. Fornasier, M. Fulchignoni, P. Hasselmann, F. Merlin, A. Praet, E. B. Bierhaus, O. Billett, A. Boggs, B. Buck, S. Carlson-Kelly, J.Cerna, K. Chaffin, E. Church, M. Coltrin, J. Daly, A. Deguzman, R. Dubisher, D. Eckart, D. Ellis, P. Falkenstern, A. Fisher, M. E. Fisher, P. Fleming, K. Fortney, S. Francis, S. Freund, S. Gonzales, P. Haas, A. Hasten, D. Hauf, A. Hilbert, D. Howell, F. Jaen, N. Jayakody, M. Jenkins, K. Johnson, M. Lefevre, H. Ma, C. Mario, K. Martin, C. May, M. McGee, B. Miller, C. Miller, G. Miller, A. Mirfakhrai, E. Muhle, C. Norman, R. Olds, C. Parish, M. Ryle, M. Schmitzer, P. Sherman, M. Skeen, M. Susak, B. Sutter, Q. Tran, C. Welch, R. Witherspoon, J. Wood, J. Zareski, M. Arvizu-Jakubicki, E. Asphaug, E. Audi, R.-L. Ballouz, R. Bandrowski, S. Bendall, H. Bloomenthal, D. Blum, J. Brodbeck, K. N. Burke, M. Chojnacki, A. Colpo, J. Contreras, J. Cutts, D. Dean, B. Diallo, D. Drinnon, K. Drozd, R. Enos, C. Fellows, T. Ferro, M. R. Fisher, G. Fitzgibbon, M. Fitzgibbon, J. Forelli, T. Forrester, I. Galinsky, R. Garcia, A. Gardner, N. Habib, D. Hamara, D. Hammond, K. Hanley, K. Harshman, K. Herzog, D. Hill, C. Hoekenga, S. Hooven, E. Huettner, A. Janakus, J. Jones, T. R. Kareta, J. Kidd, K. Kingsbury, L. Koelbel, J. Kreiner, D. Lambert, C. Lewin, B. Lovelace, M. Loveridge, M. Lujan, C. K. Maleszewski, R. Malhotra, K. Marchese, E. McDonough, N. Mogk, V. Morrison, E. Morton, R. Munoz, J. Nelson, J. Padilla, R. Pennington, A. Polit, N. Ramos, V. Reddy, M. Riehl, S. Salazar, S. R. Schwartz, S. Selznick, N. Shultz, S. Stewart, S. Sutton, T. Swindle, Y. H. Tang, M. Westermann, D. Worden, T. Zega, Z. Zeszut, A. Bjurstrom, L. Bloomquist, C. Dickinson, E. Keates, J. Liang, V. Nifo, A. Taylor, F. Teti, M. Caplinger, H. Bowles, S. Carter, S. Dickenshied, D. Doerres, T. Fisher, W. Hagee, J. Hill, M. Miner, D. Noss, N. Piacentine, M. Smith, A. Toland, P. Wren, M. Bernacki, D. Pino Munoz, S.-i. Watanabe, S. A. Sandford, A. Aqueche, B. Ashman, M. Barker, A. Bartels, K. Berry, B. Bos, R. Burns, A. Calloway, R. Carpenter, N. Castro, R. Cosentino, J. Donaldson, J. Elsila Cook, C. Emr, D. Everett, D. Fennell, K. Fleshman, D. Folta, D. Gallagher, J. Garvin, K. Getzandanner, D. Glavin, S. Hull, K. Hyde, H. Ido, A. Ingegneri, N. Jones, P. Kaotira, L. F. Lim, A. Liounis, C. Lorentson, D. Lorenz, J. Lyzhoft, E. M. Mazarico, R. Mink, W. Moore, M. Moreau, S. Mullen, J. Nagy, G. Neumann, J. Nuth, D. Poland, D. C. Reuter, L. Rhoads, S. Rieger, D. Rowlands, D. Sallitt, A. Scroggins, G. Shaw, A. A. Simon, J. Swenson, P. Vasudeva, M. Wasser, R. Zellar, J. Grossman, G. Johnston, M. Morris, J. Wendel, A. Burton, L. P. Keller, L. Mcnamara, S. Messenger, K. Messenger, A. Nguyen, K. Righter, E. Queen, K. Bellamy, K. Dill, S. Gardner, M. Giuntini, B. Key, J. Kissell, D. Patterson, D. Vaughan, B. Wright, R. W. Gaskell, L. Le Corre, J.-Y. Li, J. L. Molaro, E. E. Palmer, M. A. Siegler, P. Tricarico, J. R. Weirich, X.-D. Zou, T. Ireland, K. Tait, P. Bland, S. Anwar, N. Bojorquez-Murphy, P. R. Christensen, C. W. Haberle, G. Mehall, K. Rios, I. Franchi, B. Rozitis, C. B. Beddingfield, J. Marshall, D. N. Brack, A. S. French, J. W. McMahon, E. R. Jawin, T. J. McCoy, S. Russell, M. Killgore, J. L. Bandfield, B. C. Clark, M. Chodas, M. Lambert, R. A. Masterson, M. G. Daly, J. Freemantle, J. A. Seabrook, K. Craft, R. T. Daly, C. Ernst, R. C. Espiritu, M. Holdridge, M. Jones, A. H. Nair, L. Nguyen, J. Peachey, M. E. Perry, J. Plescia, J. H. Roberts, R. Steele, R. Turner, J. Backer, K. Edmundson, J. Mapel, M. Milazzo, S. Sides, C. Manzoni, B. May, M. Delbo, G. Libourel, P. Michel, A. Ryan, F. Thuillet, and B. Marty

Subjects
Astronomy, Exobiology
Abstract

NASA’S Origins, Spectral Interpretation, Resource Identification and Security-Regolith Explorer (OSIRIS-REx) spacecraft recently arrived at the near-Earth asteroid (101955) Bennu, a primitive body that represents the objects that may have brought prebiotic molecules and volatiles such as water to Earth1. Bennu is a low-albedo B-type asteroid2 that has been linked to organic-rich hydrated carbonaceous chondrites3. Such meteorites are altered by ejection from their parent body and contaminated by atmospheric entry and terrestrial microbes. Therefore, the primary mission objective is to return a sample of Bennu to Earth that is pristine—that is, not affected by these processes4. The OSIRIS-REx spacecraft carries a sophisticated suite of instruments to characterize Bennu’s global properties, support the selection of a sampling site and document that site at a sub-centimetre scale5,6,7,8,9,10,11. Here we consider early OSIRIS-REx observations of Bennu to understand how the asteroid’s properties compare to pre-encounter expectations and to assess the prospects for sample return. The bulk composition of Bennu appears to be hydrated and volatile-rich, as expected. However, in contrast to pre-encounter modelling of Bennu’s thermal inertia12 and radar polarization ratios13—which indicated a generally smooth surface covered by centimetre-scale particles—resolved imaging reveals an unexpected surficial diversity. The albedo, texture, particle size and roughness are beyond the spacecraft design specifications. On the basis of our pre-encounter knowledge, we developed a sampling strategy to target 50-metre-diameter patches of loose regolith with grain sizes smaller than two centimetres4. We observe only a small number of apparently hazard-free regions, of the order of 5 to 20 metres in extent, the sampling of which poses a substantial challenge to mission success.

Published
2019
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3. The operational environment and rotational acceleration of asteroid (101955) Bennu from OSIRIS-REx observations

Author

C. W. Hergenrother, C. K. Maleszewski, M. C. Nolan, J.-Y. Li, C. Y. Drouet d’Aubigny, F. C. Shelly, E. S. Howell, T. R. Kareta, M. R. M. Izawa, M. A. Barucci, E. B. Bierhaus, S. R. Chesley, B. E. Clark, E. J. Christensen, D. N. DellaGiustina, S. Fornasier, D. R. Golish, C. M. Hartzell, B. Rizk, D. J. Scheeres, P. H. Smith, X.-D. Zou, D. S. Lauretta, Jason Peter Dworkin, D.E. Highsmith, J. Small, D. Vokrouhlický, N.E. Bowles, E. Brown, K.L. Donaldson Hanna, T. Warren, C. Brunet, R.A. Chicoine, S. Desjardins, D. Gaudreau, T. Haltigin, S. Millington-Veloza, A. Rubi, J. Aponte, N. Gorius, A. Lunsford, B. Allen, J. Grindlay, D. Guevel, D. Hoak, J. Hong, D.L. Schrader, J. Bayron, O. Golubov, P. Sánchez, J. Stromberg, M. Hirabayashi, C.M. Hartzell, S. Oliver, M. Rascon, A. Harch, J. Joseph, S. Squyres, D. Richardson, J.P. Emery, L. McGraw, R. Ghent, R.P. Binzel, M.M. Al Asad, C.L. Johnson, L. Philpott, H.C.M. Susorney, E.A. Cloutis, R.D. Hanna, H.C. Connolly Jr, F. Ciceri, A.R. Hildebrand, E.-M. Ibrahim, L. Breitenfeld, T. Glotch, A.D. Rogers, B.E. Clark, S. Ferrone, C.A. Thomas, H. Campins, Y. Fernandez, W. Chang, A. Cheuvront, D. Trang, S. Tachibana, H. Yurimoto, J.R. Brucato, G. Poggiali, M. Pajola, E. Dotto, E. Mazzotta Epifani, M.K. Crombie, C. Lantz, M.R.M. Izawa, J. de Leon, J. Licandro, J.L.Rizos Garcia, S. Clemett, K. Thomas-Keprta, S. Van wal, M. Yoshikawa, J. Bellerose, S. Bhaskaran, C. Boyles, S.R. Chesley, C.M. Elder, D. Farnocchia, A. Harbison, B. Kennedy, A. Knight, N. Martinez-Vlasoff, N. Mastrodemos, T. McElrath, W. Owen, R. Park, B. Rush, L. Swanson, Y. Takahashi, D. Velez, K. Yetter, C. Thayer, C. Adam, P. Antreasian, J. Bauman, C. Bryan, B. Carcich, M. Corvin, J. Geeraert, J. Hoffman, J.M. Leonard, E. Lessac-Chenen, A. Levine, J. McAdams, L. McCarthy, D. Nelson, B. Page, J. Pelgrift, E. Sahr, K. Stakkestad, D. Stanbridge, D. Wibben, B. Williams, K. Williams, P. Wolff, P. Hayne, D. Kubitschek, M.A. Barucci, J.D.P. Deshapriya, M. Fulchignoni, P. Hasselmann, F. Merlin, A. Praet, E.B. Bierhaus, O. Billett, A. Boggs, B. Buck, S. Carlson-Kelly, J. Cerna, K. Chaffin, E. Church, M. Coltrin, J. Daly, A. Deguzman, R. Dubisher, D. Eckart, D. Ellis, P. Falkenstern, A. Fisher, M.E. Fisher, P. Fleming, K. Fortney, S. Francis, S. Freund, S. Gonzales, P. Haas, A. Hasten, D. Hauf, A. Hilbert, D. Howell, F. Jaen, N. Jayakody, M. Jenkins, K. Johnson, M. Lefevre, H. Ma, C. Mario, K. Martin, C. May, M. McGee, B. Miller, C. Miller, G. Miller, A. Mirfakhrai, E. Muhle, C. Norman, R. Olds, C. Parish, M. Ryle, M. Schmitzer, P. Sherman, M. Skeen, M. Susak, B. Sutter, Q. Tran, C. Welch, R. Witherspoon, J. Wood, J. Zareski, M. Arvizu-Jakubicki, E. Asphaug, E. Audi, R.-L. Ballouz, R. Bandrowski, K.J. Becker, T.L. Becker, S. Bendall, C.A. Bennett, H. Bloomenthal, D. Blum, W.V. Boynton, J. Brodbeck, K.N. Burke, M. Chojnacki, A. Colpo, J. Contreras, J. Cutts, C. Y. Drouet d'Aubigny, D. Dean, D.N. DellaGiustina, B. Diallo, D. Drinnon, K. Drozd, H.L. Enos, R. Enos, C. Fellows, T. Ferro, M.R. Fisher, G. Fitzgibbon, M. Fitzgibbon, J. Forelli, T. Forrester, I. Galinsky, R. Garcia, A. Gardner, D.R. Golish, N. Habib, D. Hamara, D. Hammond, K. Hanley, K. Harshman, C.W. Hergenrother, K. Herzog, D. Hill, C. Hoekenga, S. Hooven, E.S. Howell, E. Huettner, A. Janakus, J. Jones, T.R. Kareta, J. Kidd, K. Kingsbury, S.S. Balram-Knutson, L. Koelbel, J. Kreiner, D. Lambert, D.S. Lauretta, C. Lewin, B. Lovelace, M. Loveridge, M. Lujan, C.K. Maleszewski, R. Malhotra, K. Marchese, E. McDonough, N. Mogk, V. Morrison, E. Morton, R. Munoz, J. Nelson, M.C. Nolan, J. Padilla, R. Pennington, A. Polit, N. Ramos, V. Reddy, M. Riehl, Y.H. Tang, M. Westermann, C.W.V. Wolner, D. Worden, T. Zega, Z. Zeszut, A. Bjurstrom, L. Bloomquist, C. Dickinson, E. Keates, J. Liang, V. Nifo, A. Taylor, F. Teti, M. Caplinger, H. Bowles, S. Carter, S. Dickenshied, D. Doerres, T. Fisher, W. Hagee, J. Hill, M. Miner, D. Noss, N. Piacentine, M. Smith, A. Toland, P. Wren, M. Bernacki, D. Pino Munoz, S.-i. Watanabe, S. A. Sandford, A. Aqueche, B. Ashman, M. Barker, A. Bartels, K. Berry, B. Bos, R. Burns, A. Calloway, R. Carpenter, N. Castro, R. Cosentino, J. Donaldson, J.P. Dworkin, J. Elsila Cook, C. Emr, D. Everett, D. Fennell, K. Fleshman, D. Folta, D. Gallagher, J. Garvin, K. Getzandanner, D. Glavin, S. Hull, K. Hyde, H. Ido, A. Ingegneri, N. Jones, P. Kaotira, L.F. Lim, A. Liounis, C. Lorentson, D. Lorenz, J. Lyzhoft, E.M. Mazarico, R. Mink, W. Moore, M. Moreau, S. Mullen, J. Nagy, G. Neumann, J. Nuth, D. Poland, D.C. Reuter, L. Rhoads, S. Rieger, D. Rowlands, D. Sallitt, A. Scroggins, G. Shaw, A.A. Simon, J. Swenson, P. Vasudeva, M. Wasser, R. Zellar, J. Grossman, G. Johnston, M. Morris, J. Wendel, A. Burton, L.P. Keller, L. McNamara, S. Messenger, K. Nakamura-Messenger, A. Nguyen, K. Righter, E. Queen, K. Bellamy, K. Dill, S. Gardner, M. Giuntini, B. Key, J. Kissell, D. Patterson, D. Vaughan, B. Wright, R.W. Gaskell, L. Le Corre, J.L. Molaro, E.E. Palmer, M.A. Siegler, P. Tricarico, J.R. Weirich, T. Ireland, K. Tait, P. Bland, S. Anwar, A.S. French, J.W. McMahon, D.J. Scheeres, E.R. Jawin, T.J. McCoy, S. Russell, M. Killgore, W.F. Bottke, V.E. Hamilton, H.H. Kaplan, K.J. Walsh, J.L. Bandfield, B.C. Clark, M. Chodas, M. Lambert, R.A. Masterson, M.G. Daly, J. Freemantle, J.A. Seabrook, O.S. Barnouin, K. Craft, R.T. Daly, C. Ernst, R.C. Espiritu, M. Holdridge, M. Jones, A.H. Nair, L. Nguyen, J. Peachey, M.E. Perry, J. Plescia, J.H. Roberts, R. Steele, R. Turner, J. Backer, K. Edmundson, J. Mapel, M. Milazzo, S. Sides, C. Manzoni, B. May, M. Delbo’, G. Libourel, P. Michel, A. Ryan, F. Thuillet, and B. Marty

Subjects
Geosciences (General)
Abstract

During its approach to asteroid (101955) Bennu, NASA’s Origins, Spectral Interpretation, Resource Identification, and Security-Regolith Explorer (OSIRIS-REx) spacecraft surveyed Bennu’s immediate environment, photometric properties, and rotation state. Discovery of a dusty environment, a natural satellite, or unexpected asteroid characteristics would have had consequences for the mission’s safety and observation strategy. Here we show that spacecraft observations during this period were highly sensitive to satellites (sub-meter scale) but reveal none, although later navigational images indicate that further investigation is needed. We constrain average dust production in September 2018 from Bennu’s surface to an upper limit of 150 g/s averaged over 34 min. Bennu’s disk-integrated photometric phase function validates measurements from the pre-encounter astronomical campaign. We demonstrate that Bennu’s rotation rate is accelerating continuously at 3.63 ± 0.52 × 10^(–6) degrees/sq. day, likely due to the Yarkovsky–O’Keefe–Radzievskii–Paddack (YORP) effect, with evolutionary implications.

Published
2019
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10. Author Correction: Shape of (101955) Bennu indicative of a rubble pile with internal stiffness

Author

M. Lefevre, Aaron S. Burton, Carina Bennett, J. A. Mapel, Renu Malhotra, Peter Fleming, J. McAdams, N. Mogk, R. L. Ballouz, P. H. Smith, V. Nifo, C. K. Maleszewski, Timothy D. Swindle, E. Dotto, Stephen R. Schwartz, C. May, J. Bayron, D. Patterson, D. Guevel, Ellen S. Howell, Humberto Campins, J. Kissell, E. Brown, J. Wood, E. Muhle, John Robert Brucato, J. Small, B. Miller, Oleksiy Golubov, R. Pennington, K. Harshman, J. Nelson, Catherine Elder, M. McGee, R. Burns, J. Contreras, S. Hull, D. Kubitschek, D. Noss, Andrew J. Liounis, J. Backer, B. May, G. Fitzgibbon, J. Donaldson, D. Worden, Bashar Rizk, R. Witherspoon, Catherine L. Johnson, Erica Jawin, G. Shaw, A. Aqueche, Dolores H. Hill, D. Folta, S. Ferrone, M. Lujan, Giovanni Poggiali, B. G. Williams, S. Selznick, Melissa A. Morris, K. Rios, Sara S. Russell, D. Lambert, J. Hong, Jeffrey B. Plescia, H. Bloomenthal, D. Drinnon, Olivier S. Barnouin, Derek S. Nelson, Amanda E. Toland, Michael C. Moreau, J. A. Seabrook, K. Dill, A. Mirfakhrai, K. Hyde, J. D. P. Deshapriya, Hannah Kaplan, Timothy P. McElrath, Juliette I. Brodbeck, N. Ramos, S. Stewart, James B. Garvin, Sei-ichiro Watanabe, M. Arvizu-Jakubicki, Jason P. Dworkin, Matthew A. Siegler, Collin Lewin, Masatoshi Hirabayashi, L. Bloomquist, S. Gardner, Keiko Nakamura-Messenger, A. H. Nair, M. Schmitzer, P. Haas, Julie Bellerose, Dolan E. Highsmith, L. Koelbel, C. C. Lorentson, J. Zareski, E. Queen, S. R. Chesley, Philip A. Bland, A. Cheuvront, V. E. Hamilton, Ronald G. Mink, N. Mastrodemos, H. C. Connolly, K. Bellamy, M. Killgore, A. Gardner, Y. Takahashi, M. Lambert, R. C. Espiritu, Z. Zeszut, E. T. Morton, Kevin J. Walsh, Timothy D. Glotch, M. Skeen, Brian Kennedy, Matthew R.M. Izawa, G. Neumann, F. Teti, D. Doerres, A. Hasten, F. Ciceri, D. Howell, A. Deguzman, J. Nagy, D. Vaughan, H. Ma, C. Lantz, D. N. Brack, David K. Hammond, Erwan Mazarico, Leilah K. McCarthy, L. Rhoads, Kathleen L. Craft, C. Welch, Jay W. McMahon, C. L. Parish, D. C. Reuter, M. Giuntini, N. Castro, Clive Dickinson, J. Kreiner, K. Kingsbury, S. Dickenshied, Joseph A. Nuth, Alan R. Hildebrand, Erik Asphaug, H. Ido, Eric M. Sahr, A. Harbison, Arlin E. Bartels, T. Forrester, D. Eckart, R. Bandrowski, Michael K. Barker, Robert Gaskell, J. Wendel, S. Freund, Marc Bernacki, Ryan S. Park, A. Taylor, E. B. Bierhaus, S. Millington-Veloza, J. Stromberg, L. B. Breitenfeld, K. Stakkestad, D. Ellis, Timothy J. McCoy, M. Susak, Richard G. Cosentino, C. Manzoni, Hisayoshi Yurimoto, C. Drouet d'Aubigny, A. Bjurstrom, Masako Yoshikawa, S. Francis, J. Peachey, J. Geeraert, K. Marchese, O. Billett, M. Rascon, F. Jaen, B. Diallo, Martin Miner, Kris J. Becker, E. Mazzotta Epifani, Florian Thuillet, A. Knight, James H. Roberts, Pasquale Tricarico, Edward A. Cloutis, T. Fisher, Dale Stanbridge, A. Colpo, Osiris-Rex Team, S. Gonzales, Q. Tran, M. K. Crombie, John Marshall, N. Bojorquez-Murphy, David Vokrouhlický, Allen W. Lunsford, H. Bowles, K. L. Edmundson, R. A. Masterson, Peter G. Antreasian, N. Gorius, Benjamin Rozitis, D. Pino Muñoz, S. Carlson-Kelly, C. Thayer, J. Elsila Cook, B. C. Clark, N. Piacentine, José C. Aponte, M. Al Asad, M. A. Barucci, D. Blum, P. Falkenstern, Neil Bowles, Matthew Chojnacki, J. M. Leonard, J. Daly, K. Yetter, M. R. Fisher, Jeffrey N. Grossman, A. Boggs, N. Jayakody, Cristina A. Thomas, C.M. Ernst, Namrah Habib, J. N. Kidd, R. J. Steele, Andrew B. Calloway, Andrew Ryan, Kimberly T. Tait, Paul O. Hayne, J. Y. Li, K. L. Berry, William V. Boynton, Yanga R. Fernandez, D. A. Lorenz, M. Wasser, Daniel J. Scheeres, K. Fortney, A. Scroggins, B. Allen, B. Sutter, T. Ferro, Jonathan Joseph, Derek C. Richardson, D. Hoak, Brian Carcich, W. Chang, P. Wren, C. Boyles, Kaj E. Williams, B. Marty, J. Liang, J. Hoffman, A. Harch, Daniel R. Wibben, Jamie Molaro, S. Rieger, R. Enos, C. W. Hergenrother, Stephen R. Sutton, J. Grindlay, E. J. Lessac-Chenen, E. Huettner, C. Norman, P. Sherman, L. Swanson, M. Coltrin, S. Van wal, B. Buck, A. Fisher, Kevin Righter, Brian Rush, David D. Rowlands, Lauren McGraw, A. Levine, K. Drozd, D. Gaudreau, A. Nguyen, S. Sides, M. Chodas, R. Dubisher, B. Ashman, Michael Caplinger, Amy Simon, W. Moore, S. S. Balram-Knutson, R. Carpenter, S. Fornasier, Shogo Tachibana, Russell Turner, Ian A. Franchi, Trevor Ireland, Chloe B. Beddingfield, D. F. Everett, M. Corvin, Lindsay P. Keller, Tammy L. Becker, S. Carter, J. L. Rizos Garcia, Mark E. Perry, E. Keates, Michael C. Nolan, P. Vasudeva, C. Fellows, K. Herzog, Mark A. Jenkins, J. R. Weirich, J. Swenson, D. R. Golish, Davide Farnocchia, Lydia C. Philpott, Rebecca R. Ghent, Hannah C.M. Susorney, S. W. Squyres, Pedro Hasselmann, J. Hill, Thomas J. Zega, B. Key, Marco Delbo, A. S. French, P. Sánchez, A. Hilbert, J. Y. Pelgrift, R. P. Binzel, L. McNamara, Vishnu Reddy, Michael Daly, Scott Messenger, Daniella DellaGiustina, Maurizio Pajola, Charles Brunet, Joshua L. Bandfield, J. Padilla, A. Janakus, M. Moreau, R. Garcia, R. A. Chicoine, P. Michel, P. Kaotira, K. S. Johnson, J. Forelli, G. Miller, K. Martin, I. Galinsky, S. Desjardins, Naru Hirata, Christine Hartzell, M. L. Jones, S. Hooven, D. Velez, R. Munoz, Carolyn M. Ernst, C. Emr, N. Martinez-Vlasoff, S. Bendall, R. Zellar, E. Church, Theodore Kareta, T. Warren, P. Wolff, V. Morrison, C. Bryan, S. Bhaskaran, N. Jones, D. Hauf, Jeremy Bauman, R. T. Daly, R. Olds, M. M. Westermann, D. K. Hamara, E. Audi, G. Johnston, Eric Palmer, Courtney Mario, Daniel P. Glavin, T. Haltigin, J. Cutts, Javier Licandro, Xiao-Duan Zou, H. L. Roper, Gregory A. Neumann, William M. Owen, S. Sugita, Y. H. Tang, Kevin Burke, H. L. Enos, D. Gallagher, William F. Bottke, K. Getzandanner, Philip R. Christensen, C. W. V. Wolner, K. Fleshman, D. Poland, J. P. Emery, M.M. Riehl, D. Fennell, D. Sallitt, A. D. Rogers, M. Fitzgibbon, John H. Jones, S. Mullen, S. Salazar, S. Oliver, A. T. Polit, J. Cerna, A. Praet, Mark E. Holdridge, E. M. Ibrahim, Coralie D. Adam, J. de León, Christopher J. Miller, M. Ryle, J. Lyzhoft, M. Loveridge, C. Hoekenga, Brent J. Bos, S. Anwar, K. Chaffin, Devin L. Schrader, B. Lovelace, Romy D. Hanna, C. D. Adam, G. L. Mehall, K. L. Donaldson Hanna, F. Merlin, B. Wright, Guy Libourel, L. F. Lim, N. Shultz, Dante S. Lauretta, K. Hanley, Beth E. Clark, L. Le Corre, K. Thomas-Keprta, Moses Milazzo, W. Hagee, B. Page, M. Fisher, E. McDonough, D. Trang, S. Clemett, A. Rubi, A. Ingegneri, Scott A. Sandford, D. Dean, J. Freemantle, Michael D. Smith, Christopher W. Haberle, L. Nguyen, M. Fulchignoni, Laboratoire d'études spatiales et d'instrumentation en astrophysique (LESIA (UMR_8109)), Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Université de Paris (UP), MINES ParisTech - École nationale supérieure des mines de Paris, Université Paris sciences et lettres (PSL), Centre de Mise en Forme des Matériaux (CEMEF), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS]Physics [physics], 010504 meteorology & atmospheric sciences, Rubble, Stiffness, engineering.material, 010502 geochemistry & geophysics, 01 natural sciences, [SDU]Sciences of the Universe [physics], engineering, medicine, General Earth and Planetary Sciences, Geotechnical engineering, medicine.symptom, Pile, [PHYS.ASTR]Physics [physics]/Astrophysics [astro-ph], Geology, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences
Abstract

International audience

Published
2020
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11. Hemispherical differences in the shape and topography of asteroid (101955) Bennu

Author

James H. Roberts, Benjamin Rozitis, Yun Zhang, E. B. Bierhaus, J. A. Seabrook, K. Getzandanner, Michael Daly, D. N. DellaGuistina, Clive Dickinson, P. Michel, Mark E. Perry, J. R. Weirich, Lydia C. Philpott, R. T. Daly, Robert Gaskell, Hannah C.M. Susorney, J. Geeraert, Andrew Ryan, Eric Palmer, G. Cunningham, Charles Brunet, M. Al Asad, Jason M. Leonard, M. C. Nolan, R. L. Ballouz, H. L. Enos, Olivier S. Barnouin, Dante S. Lauretta, D. Gaudreau, Coralie D. Adam, T. Haltigin, Bashar Rizk, Erwan Mazarico, Gregory A. Neumann, Catherine L. Johnson, Erica Jawin, Kevin J. Walsh, Johns Hopkins University Applied Physics Laboratory [Laurel, MD] (APL), Southwest Research Institute [Boulder] (SwRI), Joseph Louis LAGRANGE (LAGRANGE), Université Côte d'Azur (UCA)-Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Observatoire de la Côte d'Azur, COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Lunar and Planetary Laboratory [Tucson] (LPL), and University of Arizona

Subjects
business.product_category, 010504 meteorology & atmospheric sciences, Longitudinal ridges, [SDU.ASTR.EP]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Earth and Planetary Astrophysics [astro-ph.EP], 01 natural sciences, 0103 physical sciences, Asymmetric distribution, Altimeter, Digital elevation model, 010303 astronomy & astrophysics, Geomorphology, Southern Hemisphere, Research Articles, ComputingMilieux_MISCELLANEOUS, 0105 earth and related environmental sciences, Multidisciplinary, [SDU.ASTR]Sciences of the Universe [physics]/Astrophysics [astro-ph], Northern Hemisphere, SciAdv r-articles, Wedge (mechanical device), Asteroid, [SDU]Sciences of the Universe [physics], business, Space Sciences, Geology, Research Article
Abstract

A lidar model of asteroid (101955) Bennu has a north-south asymmetry in shape and evidence of an early partial disruption., We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu’s southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu’s history.

Published
2020
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12. CO2 Enrichment in Anode Loop and Correlation with CO Poisoning of Low Pt Anodes in PEM Fuel Cells

Author

Gabor Dipl.-Ing. Toth, Andreas Putz, S. Erbach, M. Klages, M. Ages, S. Epple, M. Heinen, and D. Gaudreau

Subjects
Materials science, Renewable Energy, Sustainability and the Environment, 020209 energy, Energy Engineering and Power Technology, Proton exchange membrane fuel cell, 02 engineering and technology, CO poisoning, 021001 nanoscience & nanotechnology, Anode, Loop (topology), Chemical engineering, 0202 electrical engineering, electronic engineering, information engineering, Fuel cells, 0210 nano-technology
Published
2018
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13. The OSIRIS-REx Laser Altimeter (OLA) Investigation and Instrument

Author

I. Aslam, Michael C. Nolan, Charles Brunet, Michael Daly, Edward B. Bierhaus, J. A. Seabrook, T. Haltigin, Olivier S. Barnouin, G. Cunningham, Clive Dickinson, D. Gaudreau, William V. Boynton, Catherine L. Johnson, A. Taylor, and Dante S. Lauretta

Subjects
010504 meteorology & atmospheric sciences, Spacecraft, business.industry, Astronomy and Astrophysics, Terrain, 01 natural sciences, Sample (graphics), Planetary science, Lidar, Space and Planetary Science, Asteroid, 0103 physical sciences, Trajectory, Altimeter, business, 010303 astronomy & astrophysics, Geology, 0105 earth and related environmental sciences, Remote sensing
Abstract

The Canadian Space Agency (CSA) has contributed to the Origins Spectral Interpretation Resource Identification Security-Regolith Explorer (OSIRIS-REx) spacecraft the OSIRIS-REx Laser Altimeter (OLA). The OSIRIS-REx mission will sample asteroid 101955 Bennu, the first B-type asteroid to be visited by a spacecraft. Bennu is thought to be primitive, carbonaceous, and spectrally most closely related to CI and/or CM meteorites. As a scanning laser altimeter, the OLA instrument will measure the range between the OSIRIS-REx spacecraft and the surface of Bennu to produce digital terrain maps of unprecedented spatial scales for a planetary mission. The digital terrain maps produced will measure $\sim7~\mbox{cm}$ per pixel globally, and $\sim3~\mbox{cm}$ per pixel at specific sample sites. In addition, OLA data will be used to constrain and refine the spacecraft trajectories. Global maps and highly accurate spacecraft trajectory estimates are critical to infer the internal structure of the asteroid. The global and regional maps also are key to gain new insights into the surface processes acting across Bennu, which inform the selection of the OSIRIS-REx sample site. These, in turn, are essential for understanding the provenance of the regolith sample collected by the OSIRIS-REx spacecraft. The OLA data also are important for quantifying any hazards near the selected OSIRIS-REx sample site and for evaluating the range of tilts at the sampling site for comparison against the capabilities of the sample acquisition device.

Published
2017
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14. Delirium assessment in hospitalized elderly patients: Italian translation and validation of the nursing delirium screening scale

Author

Stefania Di Mauro, Monica Barilaro, Jean D. Gaudreau, Candida Ester Villa, Valentina Spedale, Davide Ausili, Giulia Del Giorno, Spedale, V, Di Mauro, S, Del Giorno, G, Barilaro, M, Villa, C, Gaudreau, J, and Ausili, D

Subjects
Male, Aging, Nursing assessment, Context (language use), Comorbidity, 03 medical and health sciences, 0302 clinical medicine, Cohen's kappa, Nursing, Surveys and Questionnaires, medicine, Humans, Translations, 030212 general & internal medicine, Confusion assessment method, Reliability (statistics), Aged, Aged, 80 and over, business.industry, Incidence (epidemiology), Delirium assessment, Reproducibility of Results, Delirium, Validation study, Gold standard (test), Test (assessment), Hospitalization, Italy, ROC Curve, Nursing delirium screening scale, Female, Geriatrics and Gerontology, medicine.symptom, Mental Status Schedule, business, 030217 neurology & neurosurgery
Abstract

Background: Delirium has a high incidence pathology associated with negative outcomes. Although highly preventable, half the cases are not recognized. One major cause of delirium misdiagnosis is the absence of a versatile instrument to measure it. Aims: Our objective was to translate the nursing delirium screening scale (Nu-DESC) and evaluate its performance in Italian settings. Methods: This was a methodological study conducted in two sequential phases. The first was the Italian translation of Nu-DESC through a translation and back-translation process. The second aimed to test the inter-rater reliability, the sensibility and specificity of the instrument on a convenience sample of 101 hospitalized elderly people admitted to relevant wards of the San Gerardo Hospital in Monza. To evaluate the inter-rater reliability, two examiners tested Nu-DESC on 20 patients concurrently without comparison. To measure the sensibility and specificity of Nu-DESC, the confusion assessment method was used as a gold standard measure. Results: The inter-rater reliability (Cohen Kappa) was 0.87—an excellent agreement between examiners. The study of the ROC curve showed an AUC value of 0.9461 suggesting high test accuracy. Using 3 as a cut-off value, Nu-DESC showed 100 % sensibility and 76 % specificity. Discussion and conclusion: Further research is needed to test Nu-DESC on a larger sample. However, based on our results, Nu-DESC can be used in research and clinical practice in Italian settings because of its very good and similar performances to previous validation studies. The value of 3 appears to be the optimal cut-off in the Italian context.

Published
2017

16. The two real-time solitudes: computerized control and telecommunications

Author

Raouf Boutaba, D. Gaudreau, A. Meehaoua, and P. Freedman

Subjects
Correctness, business.industry, Order (exchange), Computer science, Taxonomy (general), Control (management), Key (cryptography), Telecommunications, business
Abstract

While the two solitudes of our title, computerized control and telecommunications, are both concerned with computerized solutions to real world problems, we suggest that they are really addressing different needs and are therefore naturally preoccupied by slightly different concerns. We present a taxonomy of key elements intended to make such differences explicit in order to promote more mutual understanding and more collaborative work where concerns are shared. In particular, we suggest that one key difference lies in the nature of the timing requirements associated with reactivity, and whether they are considered as extensions to logical correctness or performance.

Published
2002
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18. Hemispherical differences in the shape and topography of asteroid (101955) Bennu.

Author

Daly MG, Barnouin OS, Seabrook JA, Roberts J, Dickinson C, Walsh KJ, Jawin ER, Palmer EE, Gaskell R, Weirich J, Haltigin T, Gaudreau D, Brunet C, Cunningham G, Michel P, Zhang Y, Ballouz RL, Neumann G, Perry ME, Philpott L, Al Asad MM, Johnson CL, Adam CD, Leonard JM, Geeraert JL, Getzandanner K, Nolan MC, Daly RT, Bierhaus EB, Mazarico E, Rozitis B, Ryan AJ, DellaGiustina DN, Rizk B, Susorney HCM, Enos HL, and Lauretta DS

Abstract

We investigate the shape of near-Earth asteroid (101955) Bennu by constructing a high-resolution (20 cm) global digital terrain model from laser altimeter data. By modeling the northern and southern hemispheres separately, we find that longitudinal ridges previously identified in the north extend into the south but are obscured there by surface material. In the south, more numerous large boulders effectively retain surface materials and imply a higher average strength at depth to support them. The north has fewer large boulders and more evidence of boulder dynamics (toppling and downslope movement) and surface flow. These factors result in Bennu's southern hemisphere being rounder and smoother, whereas its northern hemisphere has higher slopes and a less regular shape. We infer an originally asymmetric distribution of large boulders followed by a partial disruption, leading to wedge formation in Bennu's history., (Copyright © 2020 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science. No claim to original U.S. Government Works. Distributed under a Creative Commons Attribution License 4.0 (CC BY).)

Published
2020
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19. 2,4,6-trisubstituted triazines as protein a mimetics for the treatment of autoimmune diseases.

Author

Zacharie B, Abbott SD, Bienvenu JF, Cameron AD, Cloutier J, Duceppe JS, Ezzitouni A, Fortin D, Houde K, Lauzon C, Moreau N, Perron V, Wilb N, Asselin M, Doucet A, Fafard ME, Gaudreau D, Grouix B, Sarra-Bournet F, St-Amant N, Gagnon L, and Penney CL

Subjects
Animals, Antibodies, Antinuclear immunology, Antibodies, Antinuclear metabolism, Biomimetic Materials chemistry, Enzyme-Linked Immunosorbent Assay, Humans, Immunoglobulin G immunology, Immunoglobulin G metabolism, Kidney drug effects, Kidney immunology, Lupus Erythematosus, Systemic immunology, Lupus Erythematosus, Systemic metabolism, Mice, Models, Molecular, Molecular Structure, Protein Conformation, Staphylococcal Protein A immunology, Structure-Activity Relationship, Triazines chemistry, Biomimetic Materials chemical synthesis, Biomimetic Materials pharmacology, Lupus Erythematosus, Systemic drug therapy, Staphylococcal Protein A metabolism, Triazines chemical synthesis, Triazines pharmacology
Abstract

A first-in-class series of low molecular weight trisubstituted triazines were synthesized and evaluated for their ability to mimic protein A binding to human IgG antibody. The structure-activity relationship (SAR) demonstrates that the 1,3-phenylenediamine component was essential for robust activity. Twenty-two compounds, represented by lead molecule 34, displayed significant activity compared to protein A. These compounds may prove useful for the treatment of autoimmune disease.

Published
2010
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20. Exposure effects on music preference and recognition.

Author

Peretz I, Gaudreau D, and Bonnel AM

Subjects
Adult, Analysis of Variance, Auditory Perception, Female, Health Knowledge, Attitudes, Practice, Humans, Male, Time Factors, Affect, Memory classification, Music
Abstract

In three experiments, the effects of exposure to melodies on their subsequent liking and recognition were explored. In each experiment, the subjects first listened to a set of familiar and unfamiliar melodies in a study phase. In the subsequent test phase, the melodies were repeated, along with a set of distractors matched in familiarity. Half the subjects were required to rate their liking of each melody, and half had to identify the melodies they had heard earlier in the study phase. Repetition of the studied melodies was found to increase liking of the unfamiliar melodies in the affect task and to be best for detection of familiar melodies in the recognition task (Experiments 1, 2, and 3). These memory effects were found to fade at different time delays between study and test in the affect and recognition tasks, with the latter leading to the most persistent effects (Experiment 2). Both study-to-test changes in melody timbre and manipulation of study tasks had a marked impact on recognition and little influence on liking judgments (Experiment 3). Thus, all manipulated variables were found to dissociate the memory effects in the two tasks. The results are consistent with the view that memory effects in the affect and recognition tasks pertain to the implicit and explicit forms of memory, respectively. Part of the results are, however, at variance with the literature on implicit and explicit memory in the auditory domain. Attribution of these differences to the use of musical material is discussed.

Published
1998
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21. Role of the striatum, cerebellum and frontal lobes in the automatization of a repeated visuomotor sequence of movements.

Author

Doyon J, Laforce R Jr, Bouchard G, Gaudreau D, Roy J, Poirier M, Bédard PJ, Bédard F, and Bouchard JP

Subjects
Adult, Aged, Cerebellum pathology, Corpus Striatum pathology, Female, Frontal Lobe pathology, Humans, Learning, Male, Middle Aged, Cerebellum physiology, Corpus Striatum physiology, Frontal Lobe physiology, Memory, Motor Skills physiology, Visual Perception physiology
Abstract

Recently, Doyon et al. [20] demonstrated that lesions to both the striatum and to the cerebellum in humans produce a similar deficit in the learning of a repeated visuomotor sequence, which occurs late in the acquisition process. We now report the results of two experiments that were designed to examine whether this impairment was due to a lack of automatization of the repeating sequence of finger movements by using a dual-task paradigm and by testing for long-term retention of this skill. In Experiment 1, the performance of groups of patients with Parkinson's disease, or with damage to the cerebellum or to the frontal lobes, was compared to that of matched control subjects on the Repeated Sequence Test (primary task) and the Brooks' Matrices Test (secondary task). These two tests were administered concomitantly in both early and late learning phases of the visuomotor sequence. Overall, the groups did not differ in their ability to execute the primary task. By contrast, in accordance with the predictions, patients in Stages 2-3 of Parkinson's disease or with a cerebellar lesion failed to reveal the expected increase in performance on the secondary task seen with learning, suggesting that the latter groups of patients did not have access to the same level of residual cognitive resources to complete the matrices compared to controls. In Experiment 2, the same groups of patients and control subjects were retested again 10-18 months later. They were given four blocks of 100 trials each of the repeating sequence task, followed by a questionnaire and a self-generation task that measured their declarative knowledge of that sequence. The results revealed a long-term retention impairment only in patients who changed from Stage I to Stage II of the disease (suggesting further striatal degeneration) during the one-year interval, or who had a cerebellar lesion. By contrast, performance of the three clinical groups did not differ from controls on declarative memory tests. These findings suggest that both the striatum and the cerebellum participate to the automatization process during the late (slow) learning stage of a sequence of finger movements and that these structures also play a role in the neuronal mechanism subserving long-term retention of such a motor sequence behavior.

Published
1998
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22. [Perinatal grief. Vanished dreams].

Author

Fréchette-Piperni S, Lucas J, Pinsonneault F, Bellavance C, and Gaudreau D

Subjects
Adaptation, Psychological, Female, Humans, Infant, Newborn, Pregnancy, Fetal Death, Grief, Nurse Clinicians, Nurse-Patient Relations, Parents psychology
Published
1998

23. Role of the striatum, cerebellum, and frontal lobes in the learning of a visuomotor sequence.

Author

Doyon J, Gaudreau D, Laforce R Jr, Castonguay M, Bédard PJ, Bédard F, and Bouchard JP

Subjects
Adult, Aged, Brain Damage, Chronic diagnosis, Brain Damage, Chronic physiopathology, Brain Damage, Chronic psychology, Brain Mapping, Dominance, Cerebral physiology, Female, Humans, Male, Mental Recall physiology, Middle Aged, Neural Pathways physiopathology, Parkinson Disease diagnosis, Parkinson Disease physiopathology, Parkinson Disease psychology, Practice, Psychological, Reference Values, Cerebellum physiopathology, Corpus Striatum physiopathology, Frontal Lobe physiopathology, Psychomotor Performance physiology, Serial Learning physiology
Abstract

This study was designed to examine the role of the striatum, cerebellum, and frontal lobes in the implicit learning of a visuomotor sequence. The performance of patients with idiopathic Parkinson's disease (PD), with damage to the cerebellum, or with a circumscribed lesion to the frontal lobes was thus compared to that of separate groups of matched normal control subjects on an adapted version of the Repeated Sequence Test. This paradigm consists of a visual reaction-time task with a fixed embedded sequence of finger movements to be performed based on presentation of visual stimuli. Subjects received four blocks of trials (i.e., 40 presentations of a 10-item sequence) per day over 6 training days. Following the last experimental session, subjects were also given two tests measuring their declarative knowledge of the sequence. Only PD patients with a bilateral striatal-dysfunction or patients with lesions to the cerebellum failed to improve their performance in the last three training sessions, hence suggesting an impairment late in the acquisition process. Further analyses revealed that such impairment was mainly implicit in nature, and that it could not be ascribed to a general decline in cognitive functioning, to mood disturbances, or to the severity of the motor symptoms. By contrast, the level of declarative knowledge of the sequence did not differ between the three clinical groups and their respective groups of normal subjects. These findings suggest that, unlike declarative memory, the incremental acquisition of a new visuomotor skill depends upon the integrity of both the striatum and the cerebellum, but not of the frontal lobes.

Published
1997
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24. Binding of vitamin E in mammalian tumor cells in culture.

Author

Prasad KN, Gaudreau D, and Brown J

Subjects
Animals, Cell Fractionation, Cells, Cultured, Chromatography, Gel, Cytosol metabolism, Glioma metabolism, Melanoma metabolism, Mice, Neoplasm Proteins metabolism, Neuroblastoma metabolism, Protein Binding, Rats, Neoplasms, Experimental metabolism, Vitamin E metabolism
Published
1981
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25. Vitamin E induces morphological differentiation and increases the effect of ionizing radiation on neuroblastoma cells in culture.

Author

Prasad KN, Ramanujam S, and Gaudreau D

Subjects
Animals, Clone Cells drug effects, Gamma Rays, Glioma drug therapy, Mice, Neoplasms, Experimental drug therapy, Neuroblastoma diagnostic imaging, Neuroblastoma pathology, Radiography, Cell Differentiation drug effects, Neuroblastoma drug therapy, Radiation-Sensitizing Agents, Vitamin E pharmacology
Published
1979
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