7 results
Radiofrequency ice dielectric measurements at Summit Station, Greenland
- Juan Antonio Aguilar, Patrick Allison, Dave Besson, Abby Bishop, Olga Botner, Sjoerd Bouma, Stijn Buitink, Maddalena Cataldo, Brian A. Clark, Kenny Couberly, Zach Curtis-Ginsberg, Paramita Dasgupta, Simon de Kockere, Krijn D. de Vries, Cosmin Deaconu, Michael A. DuVernois, Anna Eimer, Christian Glaser, Allan Hallgren, Steffen Hallmann, Jordan Christian Hanson, Bryan Hendricks, Jakob Henrichs, Nils Heyer, Christian Hornhuber, Kaeli Hughes, Timo Karg, Albrecht Karle, John L. Kelley, Michael Korntheuer, Marek Kowalski, Ilya Kravchenko, Ryan Krebs, Robert Lahmann, Uzair Latif, Joseph Mammo, Matthew J. Marsee, Zachary S. Meyers, Kelli Michaels, Katharine Mulrey, Marco Muzio, Anna Nelles, Alexander Novikov, Alisa Nozdrina, Eric Oberla, Bob Oeyen, Ilse Plaisier, Noppadol Punsuebsay, Lilly Pyras, Dirk Ryckbosch, Olaf Scholten, David Seckel, Mohammad Ful Hossain Seikh, Daniel Smith, Jethro Stoffels, Daniel Southall, Karen Terveer, Simona Toscano, Delia Tosi, Dieder J. Van Den Broeck, Nick van Eijndhoven, Abigail G. Vieregg, Janna Z. Vischer, Christoph Welling, Dawn R. Williams, Stephanie Wissel, Robert Young, Adrian Zink
-
- Journal:
- Journal of Glaciology , First View
- Published online by Cambridge University Press:
- 09 October 2023, pp. 1-12
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
We recently reported on the radio-frequency attenuation length of cold polar ice at Summit Station, Greenland, based on bi-static radar measurements of radio-frequency bedrock echo strengths taken during the summer of 2021. Those data also allow studies of (a) the relative contributions of coherent (such as discrete internal conducting layers with sub-centimeter transverse scale) vs incoherent (e.g. bulk volumetric) scattering, (b) the magnitude of internal layer reflection coefficients, (c) limits on signal propagation velocity asymmetries (‘birefringence’) and (d) limits on signal dispersion in-ice over a bandwidth of ~100 MHz. We find that (1) attenuation lengths approach 1 km in our band, (2) after averaging 10 000 echo triggers, reflected signals observable over the thermal floor (to depths of ~1500 m) are consistent with being entirely coherent, (3) internal layer reflectivities are ≈–60$\to$–70 dB, (4) birefringent effects for vertically propagating signals are smaller by an order of magnitude relative to South Pole and (5) within our experimental limits, glacial ice is non-dispersive over the frequency band relevant for neutrino detection experiments.
The association between area-level demographic and socioeconomic parameters and vitamin D status in Ireland
- D. Johnston, F. Byrne, H. Scully, E. Laird, P. Bellew, L. Hendrick, H. Johnson, D. Byrne, J. B. Walsh, M. Healy, V. Crowley, D. McCartney
-
- Journal:
- Proceedings of the Nutrition Society / Volume 81 / Issue OCE4 / 2022
- Published online by Cambridge University Press:
- 30 August 2022, E140
-
- Article
-
- You have access Access
- HTML
- Export citation
In situ, broadband measurement of the radio frequency attenuation length at Summit Station, Greenland
- J. A. Aguilar, P. Allison, J. J. Beatty, D. Besson, A. Bishop, O. Botner, S. Bouma, S. Buitink, M. Cataldo, B. A. Clark, Z. Curtis-Ginsberg, A. Connolly, P. Dasgupta, S. de Kockere, K. D. de Vries, C. Deaconu, M. A. DuVernois, C. Glaser, A. Hallgren, S. Hallmann, J. C. Hanson, B. Hendricks, C. Hornhuber, K. Hughes, A. Karle, J. L. Kelley, I. Kravchenko, R. Krebs, R. Lahmann, U. Latif, J. Mammo, Z. S. Meyers, K. Michaels, K. Mulrey, A. Nelles, A. Novikov, A. Nozdrina, E. Oberla, B. Oeyen, Y. Pan, H. Pandya, I. Plaisier, N. Punsuebsay, L. Pyras, D. Ryckbosch, O. Scholten, D. Seckel, M. F. H. Seikh, D. Smith, D. Southall, J. Torres, S. Toscano, D. Tosi, D. J. Van Den Broeck, N. van Eijndhoven, A. G. Vieregg, C. Welling, D. R. Williams, S. Wissel, R. Young, A. Zink
-
- Journal:
- Journal of Glaciology / Volume 68 / Issue 272 / December 2022
- Published online by Cambridge University Press:
- 30 May 2022, pp. 1234-1242
-
- Article
-
- You have access Access
- Open access
- HTML
- Export citation
-
Over the last 25 years, radiowave detection of neutrino-generated signals, using cold polar ice as the neutrino target, has emerged as perhaps the most promising technique for detection of extragalactic ultra-high energy neutrinos (corresponding to neutrino energies in excess of 0.01 Joules, or 1017 electron volts). During the summer of 2021 and in tandem with the initial deployment of the Radio Neutrino Observatory in Greenland (RNO-G), we conducted radioglaciological measurements at Summit Station, Greenland to refine our understanding of the ice target. We report the result of one such measurement, the radio-frequency electric field attenuation length $L_\alpha$. We find an approximately linear dependence of $L_\alpha$ on frequency with the best fit of the average field attenuation for the upper 1500 m of ice: $\langle L_\alpha \rangle = ( ( 1154 \pm 121) - ( 0.81 \pm 0.14) \, ( \nu /{\rm MHz}) ) \,{\rm m}$ for frequencies ν ∈ [145 − 350] MHz.
Middle Cambrian arthropods from Utah
- Derek E. G. Briggs, Bruce S. Lieberman, Jonathan R. Hendricks, Susan L. Halgedahl, Richard D. Jarrard
-
- Journal:
- Journal of Paleontology / Volume 82 / Issue 2 / March 2008
- Published online by Cambridge University Press:
- 20 May 2016, pp. 238-254
-
- Article
- Export citation
-
The Middle Cambrian Spence Shale Member (Langston Formation) and Wheeler and Marjum Formations of Utah are known to contain a diverse soft-bodied fauna, but important new paleontological material continues to be uncovered from these strata. New specimens of anomalocaridids include the largest and smallest near complete examples yet reported from Utah. New material of stem group arthropods includes two new genera and species of arachnomorphs: Nettapezoura basilika and Dicranocaris guntherorum. Other new arachnomorph material includes a new species of Leanchoilia comparable to L. protogonia Simonetta, 1970; Leanchoilia superlata? Walcott, 1912; Sidneyia Walcott, 1911a; and Mollisonia symmetrica Walcott, 1912. L. protogonia from the Burgess Shale is confirmed as a separate species and is not a composite fossil. The first example of the trilobite Elrathia kingii preserving traces of the appendages is described. In addition, new material of the bivalved arthropods Canadaspis Novozhilov in Orlov, 1960; Branchiocaris Briggs, 1976; Waptia Walcott, 1912; and Isoxys Walcott, 1890 is described.
Contributors
-
- 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
-
- Book:
- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
-
- Chapter
- Export citation
The specificity of purine base and nucleoside uptake in promastigotes of Leishmania braziliensis panamensis
- B. D. Hansen, J. Perez-Arbelo, J. F. Walkony, L. D. Hendricks
-
- Journal:
- Parasitology / Volume 85 / Issue 2 / October 1982
- Published online by Cambridge University Press:
- 06 April 2009, pp. 271-282
-
- Article
- Export citation
-
Promastigotes of Leishmania braziliensis panamensis absorbed the purines adenine, hypoxanthine, adenosine and inosine by a combination of diffusion and mediated components. When the uptake rates for these substrates were corrected for diffusion and compared, the purine bases adenine and hypoxanthine were transported at a significantly slower rate than the purine nucleosides adenosine and inosine. Competitive interactions among those purines tested confirmed the presence of mediated and diffusion components and suggested that three transport loci may be operating (Fig. 6). The first transport locus, designated Locus 1, transported inosine, Locus 2, the purine bases hypoxanthine and adenine and Locus 3, adenosine. In addition, adenine and hypoxanthine inhibited the uptake of one another competitively. A comparison of Ki values derived from double reciprocal plots of labelled hypoxanthine and adenine uptake in the presence of the unlabelled substrates as inhibitors suggested that adenine has a greater affinity for the transport locus.
Haemoflagellates: commercially available liquid media for rapid cultivation
- L. D. Hendricks, D. E. Wood, M. E. Hajduk
-
- Journal:
- Parasitology / Volume 76 / Issue 3 / June 1978
- Published online by Cambridge University Press:
- 06 April 2009, pp. 309-316
-
- Article
- Export citation
-
The successful cultivation of a variety of haemoflagellates in three different liquid media is reported. These media include medium 199, Grace's insect tissue-culture medium and Schneider's drosophila medium, each in combination with 30% (v/v) foetal calf serum. These media were used to cultivate Old and New World species of visceral and cutaneous human Leishmania, as well as Leishmania species isolated from sandflies, rodents, and reptiles. Four strains of Trypanosoma cruzi, an isolate of T. rangeli and an isolate of T. lewisi have also been cultivated in these media. One or more of these media have been used to cultivate 121 strains of haemoflagellates, including at least 14 different species (11 Leishmania and 3 Trypanosoma) and many geographic isolates or strains. The Leishmania include L. braziliensis, L. peruviana, L. mexicana, L. tropica, L. donovani, L. chagasi, L. enriettii, L. hertigi, L. hoogstraali, L. adleri, and L. agamae. Using the Schneider's based medium, we have obtained primary isolates of both cutaneous and visceral Leishmania of man and of experimentally infected laboratory rodents and canines. Freeze-dried preparations of the Schneider's based medium that were reconstituted with distilled water after 24 months of storage at ambient temperature have proven to be suitable cultivation media. This feature makes the media valuable field tools.
The various species of human Leishmania cultivated in these media have in our experience demonstrated no differences in growth rate, viability after liquid nitrogen preservation, or infectivity for laboratory animals and tissue-culture cells compared with promastigotes derived from blood-agar cultivation.