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Implication of altered α7 nicotinic receptors and amyloid deposition in the Alzheimer's brain
- K. Nakaizumi, T. Terada, E. Yoshikawa, A. Kakimoto, I. Takashi, I. Suzuki, B. Tomoyasu, K. Suzuki, Y. Magata, N. Mori, Y. Ouchi
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- Journal:
- European Psychiatry / Volume 33 / Issue S1 / March 2016
- Published online by Cambridge University Press:
- 23 March 2020, p. S199
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Introduction
Brain amyloid-β protein (Aβ) deposition is a key pathology of Alzheimer's disease (AD). Cholinergic degeneration, including reductions in α7 nicotinic acetylcholine receptors (α7-nAChR), is also known as a pathophysiology of AD. Recent imaging studies have shown cognitively normal subjects with Aβ depositions, indicating a missing link between Aβ deposition and cognitive decline.
ObjectivesTo clarify relationships among the Aβ burden, α7-nAChR availability, and cognitive declines in AD.
AimsTo measure brain Aβ deposition and α7-nAChR availability in the same patients with AD using positron emission tomography (PET).
MethodsTwenty AD patients and age-matched 20 healthy adults were studied. The α7-nAChR availability and Aβ deposition were evaluated using PET with [11C]MeQAA and [11C]PIB, respectively. Levels of specific binding were estimated by a simplified reference tissue method (BPND) for [11C]MeQAA and a tissue ratio method (SUVR) for using [11C]PIB. The values were compared with clinical measures of various cognitive functions using regions of interest (ROIs)-based and statistical parametric mapping (SPM) analyses.
Results[11C]MeQAA BPND levels were extensively lower in the cholinergic projection regions of AD. There was a significant negative correlation between [11C]PIB SUVR and [11C]MeQAA BPND in the nucleus basalis of Mynert (NBM). The NBM [11C]PIB SUVR was negatively correlated with the [11C]MeQAA BPND level in the anterior and posterior cingulate cortices, whereas the relation within the same region showed weak correlation. Also we found significant correlation between cognitive decline and [11C]MeQAA BPND levels in the NBM.
ConclusionsAβ deposition-linked α7-nAChR dysfunction may account for cognitive decline in AD.
Disclosure of interestThe authors have not supplied their declaration of competing interest.
Multiple Feedback in Low-Metallicity Massive Star Formation
- Kei E. I. Tanaka, Jonathan C. Tan, Yichen Zhang, Takashi Hosokawa
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- Journal:
- Proceedings of the International Astronomical Union / Volume 14 / Issue S344 / August 2018
- Published online by Cambridge University Press:
- 30 October 2019, pp. 190-194
- Print publication:
- August 2018
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We theoretically investigate the impact of feedback and its metallicity dependence in massive star formation from prestellar cores at all metallicity range. We include the feedback by MHD disk winds, radiation pressure, and photoevaporation solving the evolution of protostars and accretion flows self-consistently. Interestingly, we find that the feedback does not set the upper mass limit of stellar birth mass at any metallicity. At the solar metallicity, the MHD disk wind is the dominant feedback to set the star formation efficiencies (SFEs) from the prestellar cores similar to low-mass star formation. The SFE is found to be lower at lower surface density environment. The photoevaporation becomes significant at the low metallicity of Z < 10−2 Z⊙. Considering this efficient photoevaporation, we conclude that the IMF slope is steeper, i.e., massive stars are rarer at the extremely metal-poor environment of 10−5 − 10−3Z⊙. Our study raises a question on the common assumption of the universal IMF with a truncated at 100M⊙. Since the total feedback strength in the cluster/galaxy scale is sensitive to the number fraction of massive stars, the re-evaluations of IMF at various environments are necessary.
AKARI NIR spectroscopy of interstellar ices
- Takashi Onaka, Tamami I. Mori, Itsuki Sakon, Fumihiko Usui, Ronin Wu, Takashi Shimonishi
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- Journal:
- Proceedings of the International Astronomical Union / Volume 11 / Issue A29A / August 2015
- Published online by Cambridge University Press:
- 27 October 2016, pp. 319-320
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- August 2015
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The Infrared Camera (IRC) onboard AKARI has a near-infrared (2--5μm) spectroscopic capability with high sensitivity that allows us to study the major ice components in various objects. In particular, H2O and CO2 ice absorption features have been detected towards nearby galaxies, including several young stellar objects (YSOs) in the Large Magellanic Cloud (LMC), as well as a number of HII region-PDR complexes for the first time by IRC spectroscopy. While observations in the LMC show a high ratio (~0.34) of the CO2 to H2O ice column densities, the ratios in Galactic HII-region-PDR complexes are in the range of 0.1--0.2, being compatible with those found in Galactic massive YSOs in previous studies. The good correlation supports concurrent formation of the two ice species on the grain surface and the higher ratio in the low-metallicity LMC suggests possible environmental effects in the formation process.
The Formation and Destruction of Molecular Clouds and Galactic Star Formation
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- Shu-ichiro Inutsuka, Tsuyoshi Inoue, Kazunari Iwasaki, Takashi Hosokawa, Masato I. N. Kobayashi
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- Journal:
- Proceedings of the International Astronomical Union / Volume 11 / Issue S315 / August 2015
- Published online by Cambridge University Press:
- 12 September 2016, pp. 61-68
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- August 2015
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We discuss an overall picture of star formation in the Galaxy. Recent high-resolution magneto-hydrodynamical simulations of two-fluid dynamics with cooling/heating and thermal conduction have shown that the formation of molecular clouds requires multiple episodes of supersonic compression. This finding enables us to create a new scenario of molecular cloud formation through interacting shells or bubbles on galactic scales. We estimate the ensemble-averaged growth rate of individual molecular clouds, and predict the associated cloud mass function. This picture naturally explains the accelerated star formation over many million years that was previously reported by stellar age determination in nearby star forming regions. The recent claim of cloud-cloud collisions as a mechanism for forming massive stars and star clusters can be naturally accommodated in this scenario. This explains why massive stars formed in cloud-cloud collisions follows the power-law slope of the mass function of molecular cloud cores repeatedly found in low-mass star forming regions.
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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- By Zachary W. Adams, Margarita Alegría, Atalay Alem, Jordi Alonso, Victor Aparicio, Rifat Atun, Florence Baingana, Emily Baron, Marco Bertelli, Dinesh Bhugra, Sanchita Biswas, José Miguel Caldas de Almeida, Edwin Cameron, Somnath Chatterji, Erminia Colucci, Janice L. Cooper, Carla Kmett Danielson, Diego De Leo, Mary-Jo DelVecchio Good, Marten W. de Vries, Maureen S. Durkin, Xiangming Fang, Julia W. Felton, Sally Field, Andrea Fiorillo, Lance Gable, Teddy Gafna, Sandro Galea, Patrick Gatonga, Sofia Halperin-Goldstein, Yanling He, Grace A. Herbert, Sabrina Hermosilla, Simone Honikman, Takashi Izutsu, Ruwan M. Jayatunge, Janis H. Jenkins, Rachel Jenkins, Lynne Jones, Jayanthi Karunaratne, Ronald C. Kessler, Rob Keukens, Lincoln I. Khasakhala, Hanna Kienzler, Sarah Kippen Wood, M. Thomas Kishore, Robert Kohn, Natasja Koitzsch Jensen, Sheri Lapatin, Anna Lessios, Isabel Louro Bernal, Feijun Luo, Laura MacPherson, Matthew J. Maenner, Anne W. Mbwayo, David McDaid, Ingrid Meintjes, Victoria N. Mutiso, David M. Ndetei, Samuel O. Okpaku, Lijing Ouyang, Ramachandran Padmavati, Clare Pain, Duncan Pedersen, Jordan Pfau, Felipe Picon, Rodney D. Presley, Reima Pryor, Shoba Raja, Thara Rangaswamy, Jorge Rodriguez, Diana Rose, Moosa Salie, Norman Sartorius, Ester Shapiro, Manuela Silva, Daya Somasundaram, Katherine Sorsdahl, Dan J. Stein, Deborah M. Stone, Heather Stuart, Athula Sumathipala, Hema Tharoor, Rita Thom, Lay San Too, Atsuro Tsutsumi, Chris Underhill, Anne Valentine, Claire van der Westhuizen, Thandi van Heyningen, Robert van Voren, Inka Weissbecker, Gail Wyatt
- Edited by Samuel O. Okpaku
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- Essentials of Global Mental Health
- Published online:
- 05 March 2014
- Print publication:
- 27 February 2014, pp x-xiv
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- By Ted Abel, Antoine Adamantidis, Karla V. Allebrandt, Simon N. Archer, Amelie Baud, Michel Billiard, Carlos Blanco-Centurion, Diane B. Boivin, Ethan Buhr, Matthew E. Carter, Nicolas Cermakian, Jennifer H.K. Choi, S.Y. Christin Chong, Chiara Cirelli, Marc Cuesta, Thomas Curie, Yves Dauvilliers, Luis de Lecea, Derk-Jan Dijk, Stephane Dissel, Annette C. Fedson, Jonathan Flint, Marcos G. Frank, Paul Franken, Ying-Hui Fu, Thorarinn Gislason, David Gozal, Devon A. Grant, Hakon Hakonarson, Makoto Honda, Hyun Hor, Christer Hublin, Peng Jiang, Takashi Kanbayashi, Jaakko Kaprio, Andrew Kasarskis, Leila Kheirandish-Gozal, RodaRani Konadhode, Michael Lazarus, Meng Liu, Michael March, Mark F. Mehler, Keivan Kaveh Moghadam, Valérie Mongrain, Charles M. Morin, Benjamin M. Neale, Seiji Nishino, Allan I. Pack, Dheeraj Pelluru, Rosa Peraita-Adrados, Giuseppe Plazzi, David A. Prober, Louis J. Ptáček, Irfan A. Qureshi, David M. Raizen, John J. Renger, Till Roenneberg, Elizabeth J. Rossin, Takeshi Sakurai, Paul Salin, Karen D. Schilli, Eva C. Schulte, Laurent Seugnet, Paul J. Shaw, Priyattam J. Shiromani, Patrick Sleiman, Mehdi Tafti, Joseph S. Takahashi, Matthew S. Thimgan, Katsushi Tokunaga, Giulio Tononi, Fred W. Turek, Yoshihiro Urade, Hans P.A. Van Dongen, Juliane Winkelmann, Christopher J. Winrow
- Edited by Paul Shaw, Mehdi Tafti, Michael J. Thorpy
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- The Genetic Basis of Sleep and Sleep Disorders
- Published online:
- 05 November 2013
- Print publication:
- 24 October 2013, pp xi-xiv
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- By Mark S. Aloia, Ellemarije Altena, Peter Anderer, Christopher L. Asplund, Nitin Bangera, Jeroen S. Benjamins, Daniela Berg, Bohdan Bybel, Vincenza Castronovo, Suk-tak Chan, Michael W. L. Chee, Pietro Cortelli, Michael Czisch, Joseph T. Daley, Thien Thanh Dang-Vu, Yazmín de la Garza-Neme, Lourdes DelRosso, Derk-Jan Dijk, Maria Engström, Thorleif Etgen, Bruce J. Fisch, Ariane Foret, Patrice Fort, Steffen Gais, Anne Germain, Jana Godau, Andrew L. Goertzen, William A. Gomes, Ronald M. Harper, Seung Bong Hong, Romy Hoque, Scott A. Huettel, Yuichi Inoue, Alex Iranzo, Mathieu Jaspar, Zayd Jedidi, Alejandro Jiménez-Genchi, Eun Yeon Joo, Gerhard Klösch, Karsten Krakow, Rajesh Kumar, Caroline Kussé, Hans-Peter Landolt, Helmut Laufs, Jeffrey David Lewine, Camilo Libedinsky, Michael L. Lipton, Mordechai Lorberboym, Cheng Luo, Pierre-Hervé Luppi, Paul M. Macey, Pierre Maquet, Laura Mascetti, Christelle Meyer, Sarah Moens, Vincenzo Muto, Shadreck Mzengeza, Eric Nofzinger, Takashi Nomura, Daniela Perani, Jennifer R. Ramautar, Bernd Saletu, Michael T. Saletu, Gerda Saletu-Zyhlarz, Christina Schmidt, Monika Schönauer, Richard J. Schwab, Sophie Schwartz, Keivan Shifteh, Sanjib Sinha, Victor I. Spoormaker, Ryan P. J. Stocker, A. Jon Stoessl, Diederick Stoffers, A. B. Taly, Robert Joseph Thomas, Michael J. Thorpy, Emily Urry, Jason Valerio, Ysbrand D. Van Der Werf, Gilles Vandewalle, Hans P. A. Van Dongen, Eus J. W. Van Someren, Vinod Venkatraman, Frederic von Wegner, Thomas C. Wetter, Dezhong Yao
- Edited by Eric Nofzinger, University of Pittsburgh, Pierre Maquet, Université de Liège, Belgium, Michael J. Thorpy
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- Neuroimaging of Sleep and Sleep Disorders
- Published online:
- 05 March 2013
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- 07 March 2013, pp viii-xii
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Light Curve Modeling of Superluminous Supernovae
- Takashi Moriya, Sergei I. Blinnikov, Nozomu Tominaga, Naoki Yoshida, Masaomi Tanaka, Keiichi Maeda, Ken'ichi Nomoto
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- Journal:
- Proceedings of the International Astronomical Union / Volume 9 / Issue S296 / January 2013
- Published online by Cambridge University Press:
- 29 January 2014, pp. 86-89
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- January 2013
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Origins of superluminous supernovae (SLSNe) discovered by recent SN surveys are still not known well. One idea to explain the huge luminosity is the collision of dense CSM and SN ejecta. If SN ejecta is surrounded by dense CSM, the kinetic energy of SN ejecta is efficiently converted to radiation energy, making them very bright. To see how well this idea works quantitatively, we performed numerical simulations of collisions of SN ejecta and dense CSM by using one-dimensional radiation hydrodynamics code STELLA and obtained light curves (LCs) resulting from the collision. First, we show the results of our LC modeling of SLSN 2006gy. We find that physical parameters of dense CSM estimated by using the idea of shock breakout in dense CSM (e.g., Chevalier & Irwin 2011, Moriya & Tominaga 2012) can explain the LC properties of SN 2006gy well. The dense CSM's radius is about 1016 cm and its mass about 15 M⊙. It should be ejected within a few decades before the explosion of the progenitor. We also discuss how LCs change with different CSM and SN ejecta properties and origins of the diversity of H-rich SLSNe. This can potentially be a probe to see diversities in mass-loss properties of the progenitors. Finally, we also discuss a possible signature of SN ejecta-CSM interaction which can be found in H-poor SLSN.
High spatial resolution X-ray spectra of Mg, Al, Si and P L-emission observed with a newly developed soft X-ray spectrometer for EPMA
- T. Murano, H. Takahashi, N. Handa, M. Terauchi, M. Koike, T. Kawachi, I. Takashi, N. Hasegawa, M. Koeda, T. Nagano, H. Sasai, Y. Oue, Z. Yonezawa, S. Kuramoto
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- Journal:
- Microscopy and Microanalysis / Volume 18 / Issue S2 / July 2012
- Published online by Cambridge University Press:
- 23 November 2012, pp. 776-777
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- July 2012
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Extended abstract of a paper presented at Microscopy and Microanalysis 2012 in Phoenix, Arizona, USA, July 29 – August 2, 2012.
Ultraviolet-Bright Type IIP Supernovae from Massive Red Supergiants
- Takashi J. Moriya, Nozomu Tominaga, Sergei I. Blinnikov, Petr V. Baklanov, Elena I. Sorokina
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- Journal:
- Proceedings of the International Astronomical Union / Volume 7 / Issue S279 / April 2011
- Published online by Cambridge University Press:
- 05 September 2012, pp. 54-57
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- April 2011
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Red supergiants (RSGs) are progenitors of Type IIP supernovae (SNe). It is suggested that RSGs can experience a mass loss with a very high mass-loss rate (even as high as 0.01 M⊙ yr−1) due to, e.g., dynamical instabilities of their envelopes (e.g., Yoon & Cantiello (2010)). Because of the extensive mass loss, RSGs can have very dense circumstellar medium (CSM) around them. If a SN explosion occurs soon after the extensive mass loss of a RSG, the SN ejecta will collide with the dense CSM. Due to the collision, the kinetic energy of the ejecta is converted to radiation energy and such SNe with collision can be brighter than usual Type IIP SNe. By performing one-dimensional multi-group radiation hydrodynamical calculations, we investigate the effects of the collision on Type IIP SN LCs. We show that if RSGs explode within a dense CSM, the SN will be very bright, especially in ultraviolet, at early epochs. We also compare our models with the ultraviolet-bright Type IIP SN 2009kf and show that the progenitor of SN 2009kf can be a massive RSG which experienced extensive mass loss just before its explosion. We conclude that this is evidence that massive RSGs experience extensive mass loss and the existence of such mass loss can actually be the cause of the contradiction between theoretical and observational mass ranges of Type IIP SN progenitors.
Improving Electrical Conductivity and Thermal Properties of Polymers by the Addition of Carbon Nanotubes as Fillers
- Karen I. Winey, Takashi Kashiwagi, Minfang Mu
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- Journal:
- MRS Bulletin / Volume 32 / Issue 4 / April 2007
- Published online by Cambridge University Press:
- 31 January 2011, pp. 348-353
- Print publication:
- April 2007
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The remarkable electrical and thermal conductivities of isolated carbon nanotubes have spurred worldwide interest in using nanotubes to enhance polymer properties. Electrical conductivity in nanotube/polymer composites is well described by percolation, where the presence of an interconnected nanotube network corresponds to a dramatic increase in electrical conductivity ranging from 10−5 S/cm to 1 S/cm. Given the high aspect ratios and small diameters of carbon nanotubes, percolation thresholds are often reported below 1 wt% although nanotube dispersion and alignment strongly influence this value. Increases in thermal conductivity are modest (∼3 times) because the inter facial thermal re sis tance between nanotubes is considerable and the thermal conductivity of nanotubes is only 104 greater than the polymer, which forces the matrix to contribute more toward the composite thermal conductivity, as compared to the contrast in electrical conductivity, >1014. The nanotube network is also valuable for improving flame-retardant efficiency by producing a protective nanotube residue. In this ar ticle, we highlight published research results that elucidate fundamental structure–property relationships pertaining to electrical, thermal, and/or flammability properties in numerous nanotube-containing polymer composites, so that specific applications can be targeted for future commercial success.
Heavy ion beam final transport through an insulator guide in heavy ion fusion
- SHIGEO KAWATA, TETSUO SOMEYA, TAKASHI NAKAMURA, SHUJI MIYAZAKI, KOJI SHIMIZU, ALEKSANDAR I. OGOYSKI
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- Journal:
- Laser and Particle Beams / Volume 21 / Issue 1 / January 2003
- Published online by Cambridge University Press:
- 22 July 2003, pp. 27-32
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Key issues of heavy ion beam (HIB) inertial confinement fusion (ICF) include an efficient stable beam transport, beam focusing, uniform fuel pellet implosion, and so on. To realize a HIB fine focus on a fuel pellet, space-charge neutralization of incident focusing HIB is required at the HIB final transport just after a final focusing element in an HIB accelerator. In this article, an insulator annular tube guide is proposed at the final transport part, through which a HIB is transported. The physical mechanism of HIB charge neutralization based on an insulator annular guide is as follows: A local electric field created by HIB induces local discharges, and plasma is produced on the insulator inner surface. Then electrons are extracted from the plasma by the HIB net space charge. The electrons emitted neutralize the HIB space charge well.