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3. Gap-leaping and intruding western boundary currents investigated with the large Coriolis-LEGI rotating platform

Author

Pierini, Stefano, De Ruggiero, Paola, Negretti, Maria-Eletta, Schiller-Weiss, Ilana, Weiffenbach, Julia, Viboud, Samuel, Valran, Thomas, Dijkstra, Henk, Sommeria, Joël, Dipartimentodi Scienzee Tecnologie, Universitàdi Napoli Parthenope, Laboratoire des Écoulements Géophysiques et Industriels [Grenoble] (LEGI ), Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP )-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Department of Physics and Astronomy [Utrecht], Utrecht University [Utrecht], Institute for Marine and Atmospheric Research [Utrecht] (IMAU), and Viboud, Samuel

Subjects
[PHYS.MECA.MEFL] Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], [PHYS.MECA.MEFL]Physics [physics]/Mechanics [physics]/Fluid mechanics [physics.class-ph], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2019

4. Measurement of acoustic attenuation in South Pole ice

Author

A. Piegsa, P. Roth, L. Gustafsson, J. L. Kelley, K.-H. Becker, Markus Ahlers, Larissa Paul, P. O. Hulth, J. Eisch, K. Kuehn, K. Beattie, Albrecht Karle, O. Schulz, K. Meagher, T. Krings, K. Mase, Christian Spiering, R. Porrata, G. de Vries-Uiterweerd, E. A. Strahler, A. Schukraft, Delia Tosi, S. Hussain, Timo Karg, B. Semburg, S. Knops, Justin Vandenbroucke, J. H. Koehne, Samvel Ter-Antonyan, P. B. Price, Gerald Przybylski, Dirk Ryckbosch, F. Clevermann, C. Pérez de los Heros, A. Gross, Dirk Lennarz, Hermann Kolanoski, H. Wissing, A. Schultes, J. M. Clem, Jon Dumm, M. Prikockis, T. Waldenmaier, Joanna Kiryluk, D. J. Boersma, A. Van Overloop, J. J. Beatty, J. P. Rodrigues, Dj. Koskinen, T. Stezelberger, T. O. B. Schmidt, C. Ha, M. Kowalski, J. P. Yanez, Henrik J. Johansson, M. L. Benabderrahmane, M. Danninger, P. Berghaus, S. Grullon, M. J. Carson, S. Panknin, Kurt Woschnagg, F. Rothmaier, Paul Evenson, G. W. Sullivan, S.J. Lafebre, A. Silvestri, S. Euler, M. Stamatikos, Fabian Kislat, Matthias Geisler, K. Hultqvist, N. Kemming, James E. Braun, Darren Grant, H. Landsman, Paraic A. Kenny, Juanan Aguilar, Takao Kuwabara, T. Kowarik, B. Christy, A. Tamburro, B. Voigt, Anna Franckowiak, Xinhua Bai, W. Huelsnitz, K. Helbing, Christopher Wiebusch, Dmitry Chirkin, M. V. D'Agostino, K. Schatto, J. Posselt, G. Kohnen, Damian Pieloth, M. Ono, D. Hubert, G. Wikström, T. Griesel, A. Ishihara, Thomas Meures, Karen Andeen, M. Merck, Alexander Kappes, A. Goldschmidt, J. L. Bazo Alba, J. Luenemann, Yolanda Sestayo de la Cerra, L. Demiroers, K. Wiebe, G. Stephens, S. Westerhoff, R. Nahnhauer, T. Feusels, K. Hoshina, L. Koepke, T. Abu-Zayyad, O. Tarasova, K. Han, J. E. Jacobsen, Glenn Spiczak, Pratik Majumdar, J. K. Becker, Reina H. Maruyama, Carsten Rott, L. Gerhardt, R. Ehrlich, M. Matusik, T. Gluesenkamp, Spencer Klein, Tim Ruhe, M. Walter, A. Rizzo, U. Naumann, Olga Botner, A. Olivas, R. W. Ellsworth, M. Bissok, M. M. Foerster, B. Ruzybayev, R. Ganugapati, Laura C. Bradley, E. Blaufuss, M. R. Duvoort, J. C. Gallagher, D. F. Cowen, Kara Hoffman, R. L. Imlay, S. H. Seo, Xianwu Xu, O. Depaepe, S. Stoyanov, Allan Hallgren, C. Bohm, S. M. Movit, K. Laihem, N. Milke, George Japaridze, David A. Schneider, O. Engdegård, D. Berley, G. C. Hill, Michael J. Baker, Elisa Resconi, P. Niessen, L. Gladstone, J. Berdermann, H. S. Matis, D. Seckel, S. Boeser, S. Tilav, I. Taboada, Wolfgang Rhode, A. R. Fazely, Tyce DeYoung, P. A. Toale, R. C. Bay, M. Labare, T. Straszheim, J. van Santen, Juan Carlos Diaz-Velez, D. Turcan, J. Dreyer, Y. Abdou, S. Bechet, Francis Halzen, P. Redl, P. Zarzhitsky, J. W. Nam, J. P. Huelss, O. Fadiran, Karl-Heinz Kampert, H. G. Sander, Kirill Filimonov, D. R. Nygren, S. Odrowski, Chun Xu, J. M. Joseph, Rasha Abbasi, Peter Mészáros, Stijn Buitink, R. Morse, B. D. Fox, D. Bertrand, M. Wallraff, M. Gurtner, C. Roucelle, D. Z. Besson, Nathan Whitehorn, S. Cohen, J. Auffenberg, Chad Finley, C. Colnard, Jenni Adams, Subir Sarkar, S. Hickford, R. G. Stokstad, R. Wischnewski, J. Petrovic, R. M. Gunasingha, A. Slipakaj, R. J. Lauer, M. Olivo, J. A. Goodman, C. De Clercq, David A. Williams, M. Krasberg, S. W. Barwick, Q. Swillens, S. Yoshida, E. Middell, Elisa Bernardini, N. van Eijndhoven, M. Ribordy, S. Schlenstedt, G. Kroll, Todor Stanev, C. Wendt, R. Lehmann, F. Descamps, Ph. Herquet, A. Tepe, R. Franke, Kael Hanson, C. Walck, Thomas K. Gaisser, G. B. Yodh, Paolo Desiati, S. Seunarine, D. Rutledge, K. Rawlins, James Madsen, A. Homeier, Teresa Montaruli, M. Schunck, Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, APC - Cosmologie, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Dept. of Physics, University of Wisconsin-Madison, Dept. of Subatomic and Radiation Physics, University of Gent, Department of Physics and Astronomy [Tuscaloosa), University of Alabama [Tuscaloosa] (UA), University of Oxford [Oxford], University of Wuppertal, University of Delaware [Newark], Department of Physics and Astronomy [Irvine], University of California [Irvine] (UCI), University of California-University of California, University of California, Ohio State University [Columbus] (OSU), Dept. of Astronomy, Science Faculty CP230, Université libre de Bruxelles (ULB), University of Maryland [College Park], University of Maryland System-University of Maryland System, Dept. of Physics and Astronomy, University of Kansas [Lawrence] (KU), Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Stockholm University, Rheinische Friedrich-Wilhelms-Universität Bonn, Department of Physics and Astronomy [Uppsala], Uppsala University, University Park, Technische Universität Dortmund [Dortmund] (TU), École Polytechnique Fédérale, Department of Astronomy and Astrophysics [PennState], Pennsylvania State University (Penn State), Penn State System-Penn State System, Vrije Universiteit Brussel (VUB), Department of Physics and Astronomy [Utrecht], Utrecht University [Utrecht], Southern University, Humboldt-Universität zu Berlin, Department of Physics [Edmonton], University of Alberta, University of Mainz, Johannes Gutenberg - Universität Mainz (JGU), Department of Physics and Astronomy [Christchurch] (DPA), University of Canterbury [Christchurch], Université de Mons (UMons), Chiba University, University of Alaska [Anchorage], University of the West Indies, Georgia Institute of Technology [Atlanta], Physique Corpusculaire et Cosmologie - Collège de France (PCC), Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-AstroParticule et Cosmologie (APC (UMR_7164)), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, 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)

Subjects
Acoustic attenuation, Acoustics, Ice, Neutrino astronomy, South Pole, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], 010504 meteorology & atmospheric sciences, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], ice, FOS: Physical sciences, Aetiology, screening and detection [ONCOL 5], Lambda, 01 natural sciences, neutrino astronomy, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Optics, Spectrum, 0103 physical sciences, acoustics, Instrumentation and Methods for Astrophysics (astro-ph.IM), 0105 earth and related environmental sciences, Physics, 010308 nuclear & particles physics, business.industry, Attenuation, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Transmitter, Attenuation length, Astronomy and Astrophysics, Geodesy, Amplitude, Attenuation coefficient, ddc:540, Neutrino, Astrophysics - Instrumentation and Methods for Astrophysics, business, acoustic attenuation
Abstract

Using the South Pole Acoustic Test Setup (SPATS) and a retrievable transmitter deployed in holes drilled for the IceCube experiment, we have measured the attenuation of acoustic signals by South Pole ice at depths between 190 m and 500 m. Three data sets, using different acoustic sources, have been analyzed and give consistent results. The method with the smallest systematic uncertainties yields an amplitude attenuation coefficient alpha = 3.20 \pm 0.57 km^(-1) between 10 and 30 kHz, considerably larger than previous theoretical estimates. Expressed as an attenuation length, the analyses give a consistent result for lambda = 1/alpha of ~1/300 m with 20% uncertainty. No significant depth or frequency dependence has been found., Comment: 17 pages, 12 figures, published in Astroparticle Physics, 2010

Published
2011

5. The energy spectrum of atmospheric neutrinos between 2 and 200 TeV with the AMANDA-II detector

Author

Laura C. Bradley, R. Ehrlich, A. Olivas, O. Depaepe, S. Stoyanov, M. R. Duvoort, S. Seunarine, A. Slipak, S. Tilav, J. Lünemann, Peter Mészáros, J. van Santen, R. C. Bay, D. Rutledge, P. Nießen, H. G. Sander, D. Z. Besson, Juan Carlos Diaz-Velez, Chun Xu, P. Roth, J. K. Becker, J. L. Kelley, G. Stephens, Markus Ahlers, S. Westerhoff, S. Bechet, J.-P. Hülß, Jens Madsen, O. Tarasova, J. M. Joseph, M. Krasberg, Stijn Buitink, K. Rawlins, R. Porrata, P. Redl, C. Ha, R. Morse, H. Landsman, J. Auffenberg, Q. Swillens, K. Hoshina, S. Yoshida, Samvel Ter-Antonyan, M. M. Foerster, J. C. Gallagher, H. S. Matis, D. Turcan, Glenn Spiczak, F. Rothmaier, Henrik J. Johansson, Nathan Whitehorn, Matthias Geisler, T. Glüsenkamp, K. Hultqvist, M. Stamatikos, M. V. D'Agostino, M. L. Benabderrahmane, A. Schultes, A. Homeier, Allan Hallgren, Darren Grant, Teresa Montaruli, M. Ono, Francis Halzen, P. Zarzhitsky, T. Abu-Zayyad, J. L. Bazo Alba, Pratik Majumdar, O. Fadiran, U. Naumann, Larissa Paul, A. Silvestri, Carsten Rott, R. Ganugapati, M. Schunck, Ph. Herquet, J. M. Clem, Jon Dumm, M. Prikockis, T. Waldenmaier, Joanna Kiryluk, Karl-Heinz Kampert, Kirill Filimonov, T. Feusels, D. F. Cowen, P. B. Price, Christian Spiering, S. Grullon, M. J. Carson, T. Krings, E. A. Strahler, Karen Andeen, J. E. Jacobsen, Subir Sarkar, M. Bissok, K. Münich, F. Clevermann, P. Berghaus, A. Goldschmidt, Paraic A. Kenny, Juanan Aguilar, Albrecht Karle, S. Panknin, S. Knops, Justin Vandenbroucke, N. Milke, George Japaridze, O. Engdegård, T. O. B. Schmidt, Takao Kuwabara, L. Gerhardt, Hermann Kolanoski, A. Piegsa, S. Euler, J. J. Beatty, M. Kowalski, M. Danninger, Todor Stanev, C. Wendt, Kurt Woschnagg, Paul Evenson, B. Christy, Fabian Kislat, Xianwu Xu, K.-H. Becker, K. Kuehn, T. Kowarik, Dmitry Chirkin, A. Ishihara, F. Descamps, Alexander Kappes, E. Blaufuss, Anna Franckowiak, R. Nahnhauer, E. Middell, Elisa Bernardini, Chad Finley, Damian Pieloth, D. J. Boersma, R. L. Imlay, C. Bohm, A. Tepe, D. Hubert, A. Schukraft, K. Laihem, Elisa Resconi, J. Posselt, J. Berdermann, K. Meagher, A. Tamburro, Dirk Lennarz, G. W. Sullivan, B. Voigt, N. Kemming, James E. Braun, A. Van Overloop, Xinhua Bai, R. Franke, C. Walck, Jenni Adams, S.J. Lafebre, L. Köpke, S. M. Movit, Thomas K. Gaisser, G. B. Yodh, K. Beattie, O. Schulz, K. Schatto, Reina H. Maruyama, W. Huelsnitz, M. Matusik, S. Hussain, D. J. Koskinen, Spencer Klein, J. P. Rodrigues, S. Hickford, T. Stezelberger, R. G. Stokstad, Anatoli Fedynitch, Thomas Meures, K. Helbing, Dirk Ryckbosch, G. Kohnen, R. Wischnewski, Kara Hoffman, Y. Sestayo, M. Merck, M. Ribordy, R. J. Lauer, I. Taboada, J. Petrovic, R. M. Gunasingha, Wolfgang Rhode, Tim Ruhe, C. De Clercq, M. Walter, A. Rizzo, J. Dreyer, Y. Abdou, A. R. Fazely, S. Böser, M. Olivo, J. A. Goodman, David A. Williams, S. H. Seo, S. W. Barwick, D. Tosi, C. Colnard, C. Pérez de los Heros, M. Labare, S. Cohen, Axel Groß, Timo Karg, R. W. Ellsworth, G. Wikström, T. Griesel, K. Wiebe, Gerald Przybylski, K. Han, Olga Botner, B. D. Fox, D. Bertrand, M. Wallraff, M. Gurtner, C. Roucelle, K. Mase, Christopher Wiebusch, L. Demirörs, B. Ruzybayev, J. W. Nam, Kael Hanson, David A. Schneider, D. R. Nygren, D. Berley, G. C. Hill, Paolo Desiati, Michael J. Baker, N. van Eijndhoven, L. Gladstone, D. Seckel, S. Schlenstedt, S. Odrowski, Tyce DeYoung, P. A. Toale, G. Kroll, T. Straszheim, R. Lehmann, Rasha Abbasi, P. O. Hulth, J. Eisch, G. de Vries-Uiterweerd, B. Semburg, J.-H. Köhne, H. Wissing, Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Dept. of Physics, University of Wisconsin-Madison, Dept. of Subatomic and Radiation Physics, University of Gent, Department of Physics and Astronomy [Christchurch] (DPA), University of Canterbury [Christchurch], University of Oxford [Oxford], University of Wuppertal, University of Delaware [Newark], Department of Physics and Astronomy [Irvine], University of California [Irvine] (UCI), University of California-University of California, University of California, Ohio State University [Columbus] (OSU), Dept. of Astronomy, Science Faculty CP230, Université libre de Bruxelles (ULB), University of Maryland [College Park], University of Maryland System-University of Maryland System, Dept. of Physics and Astronomy, University of Kansas [Lawrence] (KU), Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Stockholm University, Rheinische Friedrich-Wilhelms-Universität Bonn, Department of Physics and Astronomy [Uppsala], Uppsala University, University Park, Technische Universität Dortmund [Dortmund] (TU), École Polytechnique Fédérale, Department of Astronomy and Astrophysics [PennState], Pennsylvania State University (Penn State), Penn State System-Penn State System, Vrije Universiteit Brussel (VUB), Department of Physics and Astronomy [Utrecht], Utrecht University [Utrecht], Southern University, Humboldt-Universität zu Berlin, Department of Physics [Edmonton], University of Alberta, Institute of Immunology, Johannes Gutenberg - Universität Mainz (JGU), Université de Mons (UMons), Chiba University, University of Alaska [Anchorage], University of the West Indies, Georgia Institute of Technology [Atlanta], Department of Physics and Astronomy [Tuscaloosa), University of Alabama [Tuscaloosa] (UA), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, and PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)

Subjects
Particle physics, AMANDA, [PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], Physics::Instrumentation and Detectors, [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Solar neutrino, Astrophysics::High Energy Astrophysical Phenomena, Atmospheric neutrinos, Cherenkov radiation, Neural net, Unfolding, neural net, FOS: Physical sciences, Aetiology, screening and detection [ONCOL 5], 01 natural sciences, 7. Clean energy, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, 010306 general physics, unfolding, Physics, High Energy Astrophysical Phenomena (astro-ph.HE), Muon, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], High Energy Physics::Phenomenology, Astronomy and Astrophysics, Solar neutrino problem, atmospheric neutrinos, Cosmic neutrino background, Neutrino detector, ddc:540, Measurements of neutrino speed, High Energy Physics::Experiment, Astrophysics::Earth and Planetary Astrophysics, Neutrino astronomy, Neutrino, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The muon and anti-muon neutrino energy spectrum is determined from 2000-2003 AMANDA telescope data using regularised unfolding. This is the first measurement of atmospheric neutrinos in the energy range 2 - 200 TeV. The result is compared to different atmospheric neutrino models and it is compatible with the atmospheric neutrinos from pion and kaon decays. No significant contribution from charm hadron decays or extraterrestrial neutrinos is detected. The capabilities to improve the measurement of the neutrino spectrum with the successor experiment IceCube are discussed., Comment: submitted to Astroparticle Physics

Published
2010

6. Search for neutrino-induced cascades with five years of AMANDA data

Author

Jenni Adams, S. Hickford, M.R. Duvoort, R. G. Stokstad, R. Wischnewski, E. Middell, Elisa Bernardini, Laura C. Bradley, P. B. Price, Thomas Meures, O. Depaepe, S. Stoyanov, M. Merck, M. Schunck, A. Piegsa, J. Auffenberg, J. A. Aguilar, R. M. Gunasingha, M. Olivo, J. A. Goodman, N. van Eijndhoven, E. Blaufuss, J. C. Davis, K. Han, H. Landsman, T. O. B. Schmidt, J. M. Clem, S. Schlenstedt, Larissa Paul, A. R. Fazely, J. L. Kelley, J. Lünemann, R. C. Bay, J. D. Eisch, I. Taboada, Juan Carlos Diaz-Velez, F. Clevermann, K. Kuehn, G. Kroll, N. Milke, George Japaridze, J. S. Miller, S. Cohen, Olga Botner, Q. Swillens, R. W. Ellsworth, S. Grullon, M. J. Carson, Paul Evenson, S. M. Movit, Jon Dumm, M. Prikockis, T. Waldenmaier, Joanna Kiryluk, O. Engdegård, R. Lehmann, S. Panknin, D. Rutledge, M. D. Baker, A. Silvestri, M. Kowalski, T. Glüsenkamp, A. Van Overloop, J. P. Rodrigues, T. Stezelberger, K. D. Hoffman, David R. Williams, Carsten Rott, Fabian Kislat, Dirk Lennarz, M. Danninger, J. S. Gallagher, G. W. Sullivan, N. Kemming, M. Labare, James E. Braun, Karen Andeen, M. Bissok, H. G. Sander, Janet Jacobsen, T. Krings, M. L. Benabderrahmane, M. Krasberg, J. W. Nam, T. Kowarik, Dmitry Chirkin, M. Ono, K. Rawlins, E. A. Strahler, Subir Sarkar, Xianwu Xu, D. R. Nygren, J. L. Bazo Alba, Timo Karg, Elisa Resconi, Alexander Kappes, Surujhdeo Seunarine, R. Nahnhauer, Hermann Kolanoski, D. Z. Besson, C. Bohm, Chun Xu, J. M. Joseph, K. Hoshina, S. Odrowski, J. J. Beatty, J. Berdermann, D. Tosi, W. Huelsnitz, Paraic A. Kenny, Takao Kuwabara, T. Feusels, J. Dreyer, J. Petrovic, Y. Abdou, Glenn Spiczak, B. Voigt, Xinhua Bai, C. Pérez de los Heros, B. Christy, J.K. Becker, A. Ishihara, S. Yoshida, U. Naumann, K. Helbing, L. Gerhardt, J. Posselt, A. Homeier, D. J. Boersma, Ph. Herquet, R. Ehrlich, A. Olivas, M. V. D'Agostino, Markus Ahlers, C. Colnard, O. Actis, Stijn Buitink, C. Roucelle, Rasha Abbasi, Pratik Majumdar, K. Beattie, K. Mase, O. Schulz, Gerald Przybylski, S. Hussain, Kael Hanson, D. J. Koskinen, P. Roth, R. Morse, Reina H. Maruyama, T. Montaruli, S.J. Lafebre, R. Porrata, G. Wikström, T. Griesel, M. Ribordy, P. O. Hulth, G. de Vries-Uiterweerd, M. Gurtner, K. Wiebe, P. Zarzhitsky, A. Tamburro, R. Ganugapati, Henrik J. Johansson, Tim Ruhe, M. Walter, A. Rizzo, Samvel Ter-Antonyan, B. Semburg, R. J. Lauer, D. F. Cowen, J.-H. Köhne, H. Wissing, Chad Finley, Paolo Desiati, C. Ha, K. Meagher, B. D. Fox, R. L. Imlay, Tareq Abu-Zayyad, A. Schultes, Anna Franckowiak, C. De Clercq, K. Schatto, G. Kohnen, J.-P. Hülß, S. Böser, S. H. Seo, D. Bertrand, H. S. Matis, S. R. Klein, S. W. Barwick, D. Turcan, Francis Halzen, M. Wallraff, O. Fadiran, Allan Hallgren, Todor Stanev, C. Wendt, Peter Mészáros, M. M. Foerster, F. Descamps, P. Berghaus, A. Tepe, S. Euler, R. Franke, C. Walck, Thomas K. Gaisser, G. B. Yodh, Damian Pieloth, D. Hubert, L. Köpke, S. Bechet, P. Redl, Christian Spiering, S. Knops, Justin Vandenbroucke, K. Woschnagg, Axel Groß, Karl-Heinz Kampert, Kirill Filimonov, M. Matusik, Y. Sestayo, G. Stephens, S. Westerhoff, Jens Madsen, F. Rothmaier, Matthias Geisler, K. Hultqvist, Darren Grant, Wolfgang Rhode, T. Straszheim, A. Slipak, S. Tilav, J. van Santen, P. Nießen, K.-H. Becker, A. Schukraft, K. Laihem, Dirk Ryckbosch, L. Demirörs, B. Ruzybayev, M. Stamatikos, A. Goldschmidt, Christopher Wiebusch, A. Karle, David A. Schneider, D. Berley, G. C. Hill, L. Gladstone, D. Seckel, Tyce DeYoung, P. A. Toale, Nathan Whitehorn, Dept. of Physics, University of Wisconsin-Madison, Dept. of Subatomic and Radiation Physics, University of Gent, Department of Physics and Astronomy [Christchurch] (DPA), University of Canterbury [Christchurch], University of Oxford [Oxford], University of Wuppertal, University of Delaware [Newark], Department of Physics and Astronomy [Irvine], University of California [Irvine] (UCI), University of California-University of California, University of California, Ohio State University [Columbus] (OSU), Dept. of Astronomy, Science Faculty CP230, Université libre de Bruxelles (ULB), Rheinische Friedrich-Wilhelms-Universität Bonn, University of Maryland [College Park], University of Maryland System-University of Maryland System, Dept. of Physics and Astronomy, University of Kansas [Lawrence] (KU), Rheinisch-Westfälische Technische Hochschule Aachen (RWTH), Stockholm University, Department of Physics and Astronomy [Uppsala], Uppsala University, University Park, Technische Universität Dortmund [Dortmund] (TU), École Polytechnique Fédérale, Max-Planck-Institut für Kernphysik (MPIK), Max-Planck-Gesellschaft, Department of Astronomy and Astrophysics [PennState], Pennsylvania State University (Penn State), Penn State System-Penn State System, Vrije Universiteit Brussel (VUB), Department of Physics and Astronomy [Utrecht], Utrecht University [Utrecht], Southern University, Humboldt-Universität zu Berlin, Department of Physics [Edmonton], University of Alberta, University of Mainz, Johannes Gutenberg - Universität Mainz (JGU), Université de Mons (UMons), Chiba University, University of Alaska [Anchorage], University of the West Indies, Georgia Institute of Technology [Atlanta], Department of Physics and Astronomy [Tuscaloosa), University of Alabama [Tuscaloosa] (UA), APC - Cosmologie, AstroParticule et Cosmologie (APC (UMR_7164)), Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Observatoire de Paris, Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-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), Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Observatoire de Paris, PSL Research University (PSL)-PSL Research University (PSL)-Université Paris Diderot - Paris 7 (UPD7)-Physique Corpusculaire et Cosmologie - Collège de France (PCC), and Collège de France (CdF)-Institut National de Physique Nucléaire et de Physique des Particules du CNRS (IN2P3)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.ASTR.HE]Physics [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], [SDU.ASTR.CO]Sciences of the Universe [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], Physics::Instrumentation and Detectors, Astrophysics::High Energy Astrophysical Phenomena, Hadron, Flux, Cosmic ray, Context (language use), Cascades, Neutrinos, Astrophysics, Aetiology, screening and detection [ONCOL 5], 01 natural sciences, [PHYS.ASTR.CO]Physics [physics]/Astrophysics [astro-ph]/Cosmology and Extra-Galactic Astrophysics [astro-ph.CO], 0103 physical sciences, 010306 general physics, Physics, Muon, 010308 nuclear & particles physics, [SDU.ASTR.HE]Sciences of the Universe [physics]/Astrophysics [astro-ph]/High Energy Astrophysical Phenomena [astro-ph.HE], High Energy Physics::Phenomenology, Astronomy and Astrophysics, Cosmic-Rays, Nuclei, High-Energy Neutrinos, Neutrino detector, 13. Climate action, High Energy Physics::Experiment, Neutrino, Neutrino astronomy
Abstract

Contains fulltext : 97339.pdf (Publisher’s version ) (Closed access) We report on the search for electromagnetic and hadronic showers ("cascades") produced by a diffuse flux of extraterrestrial neutrinos in the AMANDA neutrino telescope. Data for this analysis were recorded during 1001 days of detector livetime in the years 2000-2004. The observed event rates are consistent with the background expectation from atmospheric neutrinos and muons. An upper limit is derived for the diffuse flux of neutrinos of all flavors assuming a flavor ratio of v(e):v(mu):v(tau) = 1:1:1 at the detection site. The all-flavor flux of neutrinos with an energy spectrum Phi proportional to E(-2) is less than 5.0 x 10(-7) GeV s(-1) sr(-1) cm(-2) at a 90% C.L. Here, 90% of the simulated signal would fall within the energy range 40 TeV to 9 PeV. We discuss flux limits in the context of several specific models of extraterrestrial and prompt atmospheric neutrino production. (C) 2010 Published by Elsevier B.V.

7. Multimodal Spectroscopic Study of Amyloid Fibril Polymorphism.

Author

VandenAkker CC, Schleeger M, Bruinen AL, Deckert-Gaudig T, Velikov KP, Heeren RM, Deckert V, Bonn M, and Koenderink GH

Subjects
Amyloid chemical synthesis, Circular Dichroism, Mass Spectrometry, Microscopy, Atomic Force, Protein Structure, Secondary, Spectroscopy, Fourier Transform Infrared, Spectrum Analysis, Raman, Surface Properties, Amyloid chemistry, Lactoglobulins chemistry
Abstract

Amyloid fibrils are a large class of self-assembled protein aggregates that are formed from unstructured peptides and unfolded proteins. The fibrils are characterized by a universal β-sheet core stabilized by hydrogen bonds, but the molecular structure of the peptide subunits exposed on the fibril surface is variable. Here we show that multimodal spectroscopy using a range of bulk- and surface-sensitive techniques provides a powerful way to dissect variations in the molecular structure of polymorphic amyloid fibrils. As a model system, we use fibrils formed by the milk protein β-lactoglobulin, whose morphology can be tuned by varying the protein concentration during formation. We investigate the differences in the molecular structure and composition between long, straight fibrils versus short, wormlike fibrils. We show using mass spectrometry that the peptide composition of the two fibril types is similar. The overall molecular structure of the fibrils probed with various bulk-sensitive spectroscopic techniques shows a dominant contribution of the β-sheet core but no difference in structure between straight and wormlike fibrils. However, when probing specifically the surface of the fibrils with nanometer resolution using tip-enhanced Raman spectroscopy (TERS), we find that both fibril types exhibit a heterogeneous surface structure with mainly unordered or α-helical structures and that the surface of long, straight fibrils contains markedly more β-sheet structure than the surface of short, wormlike fibrils. This finding is consistent with previous surface-specific vibrational sum-frequency generation (VSFG) spectroscopic results ( VandenAkker et al. J. Am. Chem. Soc. , 2011 , 133 , 18030 - 18033 , DOI: 10.1021/ja206513r ). In conclusion, only advanced vibrational spectroscopic techniques sensitive to surface structure such as TERS and VSFG are able to reveal the difference in structure that underlies the distinct morphology and rigidity of different amyloid fibril polymorphs that have been observed for a large range of food and disease-related proteins.

Published
2016
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8. Stabilizing the hexagonal close packed structure of hard spheres with polymers: Phase diagram, structure, and dynamics.

Author

Edison JR, Dasgupta T, and Dijkstra M

Abstract

We study the phase behaviour of a binary mixture of colloidal hard spheres and freely jointed chains of beads using Monte Carlo simulations. Recently Panagiotopoulos and co-workers predicted [Nat. Commun. 5, 4472 (2014)] that the hexagonal close packed (HCP) structure of hard spheres can be stabilized in such a mixture due to the interplay between polymer and the void structure in the crystal phase. Their predictions were based on estimates of the free-energy penalty for adding a single hard polymer chain in the HCP and the competing face centered cubic (FCC) phase. Here we calculate the phase diagram using free-energy calculations of the full binary mixture and find a broad fluid-solid coexistence region and a metastable gas-liquid coexistence region. For the colloid-monomer size ratio considered in this work, we find that the HCP phase is only stable in a small window at relatively high polymer reservoir packing fractions, where the coexisting HCP phase is nearly close packed. Additionally we investigate the structure and dynamic behaviour of these mixtures.

Published
2016
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9. Self-Assembly of Cubes into 2D Hexagonal and Honeycomb Lattices by Hexapolar Capillary Interactions.

Author

Soligno G, Dijkstra M, and van Roij R

Abstract

Particles adsorbed at a fluid-fluid interface induce capillary deformations that determine their orientations and generate mutual capillary interactions which drive them to assemble into 2D ordered structures. We numerically calculate, by energy minimization, the capillary deformations induced by adsorbed cubes for various Young's contact angles. First, we show that capillarity is crucial not only for quantitative, but also for qualitative predictions of equilibrium configurations of a single cube. For a Young's contact angle close to 90°, we show that a single-adsorbed cube generates a hexapolar interface deformation with three rises and three depressions. Thanks to the threefold symmetry of this hexapole, strongly directional capillary interactions drive the cubes to self-assemble into hexagonal or graphenelike honeycomb lattices. By a simple free-energy model, we predict a density-temperature phase diagram in which both the honeycomb and hexagonal lattice phases are present as stable states.

Published
2016
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10. Unified functional network and nonlinear time series analysis for complex systems science: The pyunicorn package.

Author

Donges JF, Heitzig J, Beronov B, Wiedermann M, Runge J, Feng QY, Tupikina L, Stolbova V, Donner RV, Marwan N, Dijkstra HA, and Kurths J

Subjects
Stochastic Processes, Time Factors, Models, Theoretical, Nonlinear Dynamics, Software
Abstract

We introduce the pyunicorn (Pythonic unified complex network and recurrence analysis toolbox) open source software package for applying and combining modern methods of data analysis and modeling from complex network theory and nonlinear time series analysis. pyunicorn is a fully object-oriented and easily parallelizable package written in the language Python. It allows for the construction of functional networks such as climate networks in climatology or functional brain networks in neuroscience representing the structure of statistical interrelationships in large data sets of time series and, subsequently, investigating this structure using advanced methods of complex network theory such as measures and models for spatial networks, networks of interacting networks, node-weighted statistics, or network surrogates. Additionally, pyunicorn provides insights into the nonlinear dynamics of complex systems as recorded in uni- and multivariate time series from a non-traditional perspective by means of recurrence quantification analysis, recurrence networks, visibility graphs, and construction of surrogate time series. The range of possible applications of the library is outlined, drawing on several examples mainly from the field of climatology.

Published
2015
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11. Nanoscale Heterogeneity of the Molecular Structure of Individual hIAPP Amyloid Fibrils Revealed with Tip-Enhanced Raman Spectroscopy.

Author

vandenAkker CC, Deckert-Gaudig T, Schleeger M, Velikov KP, Deckert V, Bonn M, and Koenderink GH

Subjects
Amino Acid Sequence, Humans, Islet Amyloid Polypeptide metabolism, Lipids chemistry, Microscopy, Atomic Force, Microscopy, Electron, Scanning Transmission, Protein Structure, Quaternary, Protein Structure, Secondary, Spectroscopy, Fourier Transform Infrared, Surface Properties, Amyloid chemistry, Islet Amyloid Polypeptide chemistry, Spectrum Analysis, Raman methods
Abstract

Type 2 diabetes mellitus is characterized by the pathological deposition of fibrillized protein, known as amyloids. It is thought that oligomers and/or amyloid fibrils formed from human islet amyloid polypeptide (hIAPP or amylin) cause cell death by membrane damage. The molecular structure of hIAPP amyloid fibrils is dominated by β-sheet structure, as probed with conventional infrared and Raman vibrational spectroscopy. However, with these techniques it is not possible to distinguish between the core and the surface structure of the fibrils. Since the fibril surface crucially affects amyloid toxicity, it is essential to know its structure. Here the surface molecular structure and amino acid residue composition of hIAPP fibrils are specifically probed with nanoscale resolution using tip-enhanced Raman spectroscopy (TERS). The fibril surface mainly contains unordered or α-helical structures, in contrast to the β-sheet-rich core. This experimentally validates recent models of hIAPP amyloids based on NMR measurements. Spatial mapping of the surface structure reveals a highly heterogeneous surface structure. Finally, TERS can probe fibrils formed on a lipid interface, which is more representative of amyloids in vivo., (© 2015 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.)

Published
2015
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12. Effect of external electric fields on the phase behavior of colloidal silica rods.

Author

Kuijk A, Troppenz T, Filion L, Imhof A, van Roij R, Dijkstra M, and van Blaaderen A

Abstract

We examine the effect of external electric fields on the behavior of colloidal silica rods. We find that the electric fields can be used to induce para-nematic and para-smectic phases, and to reduce the number of defects in smectic phases. At high field strengths, a new crystal structure was observed that consisted of strings of rods ordered in a hexagonal pattern in which neighboring rods were shifted along their length. We also present a simple model to describe this system, which we used in computer simulations to calculate the phase diagram for rods of L/D = 6, with L the end-to-end length of the rods and D the diameter of the rods. Our theoretical predictions for the phase behavior agree well with the experimental observations.

Published
2014
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13. Optimizing immuno-labeling for correlative fluorescence and electron microscopy on a single specimen.

Author

Karreman MA, Agronskaia AV, van Donselaar EG, Vocking K, Fereidouni F, Humbel BM, Verrips CT, Verkleij AJ, and Gerritsen HC

Subjects
Freeze Substitution, Microscopy, Electron methods, Microscopy, Electron, Transmission methods, Microscopy, Fluorescence methods
Abstract

Correlative fluorescence and electron microscopy has become an indispensible tool for research in cell biology. The integrated Laser and Electron Microscope (iLEM) combines a Fluorescence Microscope (FM) and a Transmission Electron Microscope (TEM) within one set-up. This unique imaging tool allows for rapid identification of a region of interest with the FM, and subsequent high resolution TEM imaging of this area. Sample preparation is one of the major challenges in correlative microscopy of a single specimen; it needs to be apt for both FM and TEM imaging. For iLEM, the performance of the fluorescent probe should not be impaired by the vacuum of the TEM. In this technical note, we have compared the fluorescence intensity of six fluorescent probes in a dry, oxygen free environment relative to their performance in water. We demonstrate that the intensity of some fluorophores is strongly influenced by its surroundings, which should be taken into account in the design of the experiment. Furthermore, a freeze-substitution and Lowicryl resin embedding protocol is described that yields excellent membrane contrast in the TEM but prevents quenching of the fluorescent immuno-labeling. The embedding protocol results in a single specimen preparation procedure that performs well in both FM and TEM. Such procedures are not only essential for the iLEM, but also of great value to other correlative microscopy approaches., (Copyright © 2012 Elsevier Inc. All rights reserved.)

Published
2012
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14. VIS2FIX: a high-speed fixation method for immuno-electron microscopy.

Author

Karreman MA, van Donselaar EG, Gerritsen HC, Verrips CT, and Verkleij AJ

Subjects
Animals, Cell Line, Dogs, Humans, Immunohistochemistry, Lipids chemistry, Time Factors, Microscopy, Immunoelectron methods, Tissue Fixation methods
Abstract

Immuno-transmission electron microscopy (TEM) is the technique of choice for high-resolution localization of proteins in fixed specimen. Here we introduce 2 novel methods for the fixation of sections from cryo-immobilized samples that result in excellent ultrastructural preservation. These high-speed fixation techniques, both called VIS2FIX, allow for a reduction in sample preparation time from at least 1 week to only 8 h. The methods were validated in immuno-TEM experiments on THP-1 monocytes, human umbilical vein endothelial cells (HUVECs) and Madin-Darby canine kidney (MDCK-II) cells. The fixation and retention of neutral lipids is demonstrated, offering unique prospects for the application of immuno-TEM in the lipidomics field. Furthermore, the VIS2FIX methods were successfully employed in correlative fluorescence and electron microscopy., (© 2011 John Wiley & Sons A/S.)

Published
2011
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15. Seeded growth of titania colloids with refractive index tunability and fluorophore-free luminescence.

Author

Demirörs AF, Jannasch A, van Oostrum PD, Schäffer E, Imhof A, and van Blaaderen A

Subjects
Colloids, Microscopy, Confocal, Particle Size, Phase Transition, Propylamines, Silanes chemistry, Temperature, Luminescent Measurements, Titanium chemistry
Abstract

Titania is an important material in modern materials science, chemistry, and physics because of its special catalytic, electric, and optical properties. Here, we describe a novel method to synthesize colloidal particles with a crystalline titania, anatase core and an amorphous titania-shell structure. We demonstrate seeded growth of titania onto titania particles with accurate particle size tunability. The monodispersity is improved to such an extent so that colloidal crystallization of the grown microspheres becomes feasible. Furthermore, seeded growth provides separate manipulation of the core and shell. We tuned the refractive index of the amorphous shell between 1.55 and 2.3. In addition, the particles show luminescence when trace amounts of aminopropyl-triethoxysilane are incorporated into the titania matrix and are calcined at 450 °C. Our novel colloids may be useful for optical materials and technologies such as photonic crystals and optical trapping.

Published
2011
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16. Directed self-assembly of colloidal dumbbells with an electric field.

Author

Demirörs AF, Johnson PM, van Kats CM, van Blaaderen A, and Imhof A

Abstract

We demonstrate the assembly of colloidal particles with the shape of diatomic molecules ("dumbbells") into crystals that we study with confocal microscopy. The literature on the preparation of nonspherical colloidal particles has grown steadily. Assembly of these particles into regular three-dimensional crystalline lattices, however, is rarely, if ever, achieved and has not yet been studied quantitatively in 3D real space. We find that, by application of an electric field, such particles assemble quite readily. By varying the particle aspect ratio, range of interactions, and electric field strength, we find several different crystal structures of which three have never before been observed. Moreover, the electric field can be used to switch between different structures and manipulate/switch the photonic properties. Moreover, our work sheds light on fundamental questions related to the self-assembly of nonspherical particles.

Published
2010
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17. A general method to coat colloidal particles with titania.

Author

Demirörs AF, van Blaaderen A, and Imhof A

Abstract

We describe a general one-pot method for coating colloidal particles with amorphous titania. Various colloidal particles such as silica particles, large silver colloids, gibbsite platelets, and polystyrene spheres were successfully coated with a titania shell. Although there are several ways of coating different particles with titania in the literature, each of these methods is applicable to only one type of material. The present method is especially useful for giving the opportunity to cover many types of colloidal particles with titania and forgoes the use of a coupling agent or a precoating step. We can produce particles with a smooth titania layer of tunable thickness. The monodispersity, which improves during particle growth, and the high refractive index of titania make these particles potential candidates for photonic crystal applications. We also describe various ways of fabricating hollow titania shells, which have been intensively studied in the literature for their applications in electronics, catalysis, separations, and diagnostics. Note that our method initially produces amorphous shells on the particles, but these can be easily turned into crystalline titania by a calcination step. We also find that the growth of titania is a surface-reaction-limited process.

Published
2010
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18. Elastic properties of hollow colloidal particles.

Author

Zoldesi CI, Ivanovska IL, Quilliet C, Wuite GJ, and Imhof A

Abstract

The elastic properties of micrometer-sized hollow colloidal particles obtained by emulsion templating are probed by nanoindentation measurements in which point forces are applied to solvent-filled particles supported on a flat substrate. We show that the shells respond linearly up to forces of 7-21 nN, where the indentation becomes of the order of the shell thickness (20-40 nm). In the linear region, the particle deformation is reversible. The measured Young's modulus (approximately 200 MPa) is comparable to values for stiff rubbers or soft polymers. At larger applied force, we observe a crossover into a nonlinear regime, where the shells assume a buckled shape. Here, the force increases approximately as the square root of the indentation, in agreement with the theory of elasticity of thin shells. We also observe permanent deformation of the shells after probing them repetitively beyond the linear regime. Finally, the measured elastic properties of the shells nicely explain their spontaneous buckling in solution and due to drying.

Published
2008
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19. A stochastic dynamical systems view of the Atlantic Multidecadal Oscillation.

Author

Dijkstra HA, Frankcombe LM, and von der Heydt AS

Abstract

We provide a dynamical systems framework to understand the Atlantic Multidecadal Oscillation and show that this framework is in many ways similar to that of the El Niño/Southern Oscillation. A so-called minimal primitive equation model is used to represent the Atlantic Ocean circulation. Within this minimal model, we identify a normal mode of multidecadal variability that can destabilize the background climate state through a Hopf bifurcation. Next, we argue that noise is setting the amplitude of the sea surface temperature variability associated with this normal mode. The results provide support that a stochastic Hopf bifurcation is involved in the multidecadal variability as observed in the North Atlantic.

Published
2008
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20. Encapsulation of emulsion droplets by organo-silica shells.

Author

Zoldesi CI, Steegstra P, and Imhof A

Abstract

Surfactant-stabilized emulsion droplets were used as templates for the synthesis of hollow colloidal particles. Monodisperse silicone oil droplets were prepared by hydrolysis and polymerization of dimethyldiethoxysiloxane monomer, in the presence of surfactant: sodium dodecyl sulphate (SDS, anionic) or Triton X-100 (non-ionic). A sharp decrease in the average droplet radius with increasing surfactant concentration was found, with a linear dependence of the droplet radius on the logarithm of the surfactant concentration. The surfactant-stabilized oil droplets were then encapsulated with a solid shell using tetraethoxysilane, and hollow particles were obtained by exchange of the liquid core. The size and polydispersity of the oil droplets and the thickness of the shell were determined using static light scattering, and hollow particles were characterized by electron microscopy. Details on the composition of the shell material were obtained from energy-dispersive X-ray analysis. In the case of sodium dodecyl sulphate, the resulting shells were relatively thin and rough, while when Triton X-100 was used, smooth shells were obtained which could be varied in thickness from very thick ( approximately 150 nm) to very thin shells ( approximately 17 nm). Finally, hexane droplets were encapsulated using the same procedure, showing that our method can in principle be extended to a wide range of emulsions.

Published
2007
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21. Matching illumination of solid objects.

Author

Pont SC and Koenderink JJ

Subjects
Humans, Light, Visual Perception
Abstract

The appearance of objects is determined by their surface reflectance and roughness and by the light field. Conversely, human observers might derive properties of the light field from the appearance of objects. The inverse problem has no unique solution, so perceptual interactions between reflectance, roughness, and lightfield are to be expected. In two separate experiments, we tested whether observers are able to match the illumination of spheres under collimated illumination only (matching of illumination direction) and under more or less diffuse illumination (matching of illumination direction and directedness of the beam). We found that observers are quite able to match collimated illumination directions of two rendered Lambertian spheres. Matching of the collimated beam directions of a Lambertian sphere and that of a real object with arbitrary reflectance and roughness properties resulted in similar results for the azimuthal angle, but in higher variance for the polar angle. Translucent objects and a tennis ball were found to be systematic outliers. If the directedness of the beam was also varied, the direction settings showed larger variance for more diffuse illumination. The directedness settings showed an overall quite large variance and, interestingly, interacted with the polar angle settings. We discuss possible photometrical mechanisms behind these effects.

Published
2007
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22. Limits on the high-energy gamma and neutrino fluxes from the SGR 1806-20 giant flare of 27 December 2004 with the AMANDA-II detector.

Author

Achterberg A, Ackermann M, Adams J, Ahrens J, Andeen K, Atlee DW, Bahcall JN, Bai X, Baret B, Bartelt M, Barwick SW, Bay R, Beattie K, Becka T, Becker JK, Becker KH, Berghaus P, Berley D, Bernardini E, Bertrand D, Besson DZ, Blaufuss E, Boersma DJ, Bohm C, Bolmont J, Böser S, Botner O, Bouchta A, Braun J, Burgess C, Burgess T, Castermans T, Chirkin D, Christy B, Clem J, Cowen DF, D'Agostino MV, Davour A, Day CT, De Clercq C, Demirörs L, Descamps F, Desiati P, Deyoung T, Diaz-Velez JC, Dreyer J, Dumm JP, Duvoort MR, Edwards WR, Ehrlich R, Eisch J, Ellsworth RW, Evenson PA, Fadiran O, Fazely AR, Feser T, Filimonov K, Fox BD, Gaisser TK, Gallagher J, Ganugapati R, Geenen H, Gerhardt L, Goldschmidt A, Goodman JA, Gozzini R, Grullon S, Gross A, Gunasingha RM, Gurtner M, Hallgren A, Halzen F, Han K, Hanson K, Hardtke D, Hardtke R, Harenberg T, Hart JE, Hauschildt T, Hays D, Heise J, Helbing K, Hellwig M, Herquet P, Hill GC, Hodges J, Hoffman KD, Hommez B, Hoshina K, Hubert D, Hughey B, Hulth PO, Hultqvist K, Hundertmark S, Hülss JP, Ishihara A, Jacobsen J, Japaridze GS, Jones A, Joseph JM, Kampert KH, Karle A, Kawai H, Kelley JL, Kestel M, Kitamura N, Klein SR, Klepser S, Kohnen G, Kolanoski H, Köpke L, Krasberg M, Kuehn K, Landsman H, Leich H, Liubarsky I, Lundberg J, Madsen J, Mase K, Matis HS, McCauley T, McParland CP, Meli A, Messarius T, Mészáros P, Miyamoto H, Mokhtarani A, Montaruli T, Morey A, Morse R, Movit SM, Münich K, Nahnhauer R, Nam JW, Niessen P, Nygren DR, Ogelman H, Olbrechts P, Olivas A, Patton S, Peña-Garay C, Pérez de Los Heros C, Piegsa A, Pieloth D, Pohl AC, Porrata R, Pretz J, Price PB, Przybylski GT, Rawlins K, Razzaque S, Refflinghaus F, Resconi E, Rhode W, Ribordy M, Rizzo A, Robbins S, Roth P, Rott C, Rutledge D, Ryckbosch D, Sander HG, Sarkar S, Schlenstedt S, Schmidt T, Schneider D, Seckel D, Seo SH, Seunarine S, Silvestri A, Smith AJ, Solarz M, Song C, Sopher JE, Spiczak GM, Spiering C, Stamatikos M, Stanev T, Steffen P, Stezelberger T, Stokstad RG, Stoufer MC, Stoyanov S, Strahler EA, Straszheim T, Sulanke KH, Sullivan GW, Sumner TJ, Taboada I, Tarasova O, Tepe A, Thollander L, Tilav S, Toale PA, Turcan D, van Eijndhoven N, Vandenbroucke J, Van Overloop A, Voigt B, Wagner W, Walck C, Waldmann H, Walter M, Wang YR, Wendt C, Wiebusch CH, Wikström G, Williams DR, Wischnewski R, Wissing H, Woschnagg K, Xu XW, Yodh G, Yoshida S, and Zornoza JD

Abstract

On 27 December 2004, a giant gamma flare from the Soft Gamma-Ray Repeater 1806-20 saturated many satellite gamma-ray detectors, being the brightest transient event ever observed in the Galaxy. AMANDA-II was used to search for down-going muons indicative of high-energy gammas and/or neutrinos from this object. The data revealed no significant signal, so upper limits (at 90% C.L.) on the normalization constant were set: 0.05(0.5) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the gamma flux and 0.4(6.1) TeV-1 m;{-2} s;{-1} for gamma=-1.47 (-2) in the high-energy neutrino flux.

Published
2006
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23. Nonspatial visual attention explained by spatial attention plus limited storage.

Author

de Haan E, Lutz C, and Noest AJ

Subjects
Contrast Sensitivity, Fixation, Ocular, Humans, Memory, Short-Term, Problem Solving, Attention, Mental Recall, Orientation, Pattern Recognition, Visual
Abstract

The use of nonspatial attentional mechanisms in search tasks was investigated by presenting observers with stimuli that contained 4-12 elements located on a circle around the fixation point. The elements differed in one of six nonspatial 'dimensions', namely orientation, contrast, scale, number of cycles, 'shape', and place in the alphabet. The target element of the search task differed from trial to trial but was always presented to the observer as a nonspatial, visual cue. This cue was displayed either before the stimulus (precue) or after the stimulus (postcue). Whereas a precue creates optimal conditions for the use of nonspatial attentional mechanisms, a postcue precludes benefits from their use. The fact that performance was better in the case of precued stimuli than in the case of postcued stimuli indicates that observers employed nonspatial attentional mechanisms. In the final analysis, however, the effect of nonspatial attention reduces to spatial attention in combination with limited storage capacity.

Published
1996
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