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Mean-level correspondence and moment-to-moment synchrony in adolescent and parent affect: Exploring associations with adolescent age and internalizing and externalizing symptoms
- Lauren M. Henry, Kelly H. Watson, David A. Cole, Sofia Torres, Allison Vreeland, Rachel E. Siciliano, Allegra S. Anderson, Meredith A. Gruhn, Abagail Ciriegio, Cassandra Broll, Jon Ebert, Tarah Kuhn, Bruce E. Compas
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- Journal:
- Development and Psychopathology / Volume 35 / Issue 2 / May 2023
- Published online by Cambridge University Press:
- 07 April 2022, pp. 809-822
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Interactions with parents are integral in shaping the development of children’s emotional processes. Important aspects of these interactions are overall (mean level) affective experience and affective synchrony (linkages between parent and child affect across time). Respectively, mean-level affect and affective synchrony reflect aspects of the content and structure of dyadic interactions. Most research on parent–child affect during dyadic interactions has focused on infancy and early childhood; adolescence, however, is a key period for both normative emotional development and the emergence of emotional disorders. We examined affect in early to mid-adolescents (N = 55, Mage = 12.27) and their parents using a video-mediated recall task of 10-min conflict-topic discussions. Using multilevel modeling, we found evidence of significant level-2 effects (mean affect) and level-1 effects (affective synchrony) for parents and their adolescents. Level-2 and level-1 associations were differentially moderated by adolescent age and adolescent internalizing and externalizing symptoms. More specifically, parent–adolescent synchrony was stronger when adolescents were older and had more internalizing problems. Further, more positive adolescent mean affect was associated with more positive parent affect (and vice versa), but only for dyads with low adolescent externalizing problems. Results underscore the importance of additional research examining parent–child affect in adolescence.
Early life adversity blunts responses to pioglitazone in depressed, overweight adults
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- Thalia K. Robakis, Kathleen Watson-Lin, Tronita E. Wroolie, Alison Myoraku, Carla Nasca, Benedetta Bigio, Bruce McEwen, Natalie L. Rasgon
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- European Psychiatry / Volume 55 / January 2019
- Published online by Cambridge University Press:
- 01 January 2020, pp. 4-9
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Purpose:
Early life adversity is associated with both metabolic impairment and depression in adulthood, as well as with poorer responses to antidepressant medications. It is not yet known whether individual differences in sensitivity to antidiabetic medications could also be related to early life adversity. We examined whether a history of early life adversity affected the observed changes in metabolic function and depressive symptoms in a randomized trial of pioglitazone for augmentation of standard treatments for depression.
Purpose:Early life adversity is associated with both metabolic impairment and depression in adulthood, as well as with poorer responses to antidepressant medications. It is not yet known whether individual differences in sensitivity to antidiabetic medications could also be related to early life adversity. We examined whether a history of early life adversity affected the observed changes in metabolic function and depressive symptoms in a randomized trial of pioglitazone for augmentation of standard treatments for depression.
Findings:We found that early life adversity significantly impaired the metabolic response to pioglitazone. Effects on depressive symptoms did not reach significance, but nonetheless suggested that pioglitazone could mitigate the depressant effects of childhood adversity, only among those insulin resistant at baseline.
Conclusions:We conclude that a history of early life adversity may impair the body’s ability to respond to insulin sensitizing pharmacotherapy, and furthermore that its contribution to resistant depression may function in part via the generation of an insulin resistant phenotype.
Visuospatial Functioning in the Primary Progressive Aphasias
- Christa L. Watson, Katherine Possin, I. Elaine Allen, H. Isabel Hubbard, Marita Meyer, Ariane E. Welch, Gil D. Rabinovici, Howard Rosen, Katherine P. Rankin, Zachary Miller, Miguel A. Santos-Santos, Joel H. Kramer, Bruce L. Miller, Maria Luisa Gorno-Tempini
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- Journal:
- Journal of the International Neuropsychological Society / Volume 24 / Issue 3 / March 2018
- Published online by Cambridge University Press:
- 17 October 2017, pp. 259-268
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Objectives: The aim of this study was to identify whether the three main primary progressive aphasia (PPA) variants would show differential profiles on measures of visuospatial cognition. We hypothesized that the logopenic variant would have the most difficulty across tasks requiring visuospatial and visual memory abilities. Methods: PPA patients (n=156), diagnosed using current criteria, and controls were tested on a battery of tests tapping different aspects of visuospatial cognition. We compared the groups on an overall visuospatial factor; construction, immediate recall, delayed recall, and executive functioning composites; and on individual tests. Cross-sectional and longitudinal comparisons were made, adjusted for disease severity, age, and education. Results: The logopenic variant had significantly lower scores on the visuospatial factor and the most impaired scores on all composites. The nonfluent variant had significant difficulty on all visuospatial composites except the delayed recall, which differentiated them from the logopenic variant. In contrast, the semantic variants performed poorly only on delayed recall of visual information. The logopenic and nonfluent variants showed decline in figure copying performance over time, whereas in the semantic variant, this skill was remarkably preserved. Conclusions: This extensive examination of performance on visuospatial tasks in the PPA variants solidifies some previous findings, for example, delayed recall of visual stimuli adds value in differential diagnosis between logopenic variant PPA and nonfluent variant PPA variants, and illuminates the possibility of common mechanisms that underlie both linguistic and non-linguistic deficits in the variants. Furthermore, this is the first study that has investigated visuospatial functioning over time in the PPA variants. (JINS, 2018, 24, 259–268)
Predicting the effect of rotation design on N, P, K balances on organic farms using the NDICEA model - CORRIGENDUM
- Laurence G. Smith, Davide Tarsitano, Cairistiona F. E. Topp, Stephanie K. Jones, Catherine L. Gerrard, Bruce D. Pearce, Adrian G. Williams, Christine A. Watson
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- Renewable Agriculture and Food Systems / Volume 31 / Issue 6 / December 2016
- Published online by Cambridge University Press:
- 10 February 2016, p. 574
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Predicting the effect of rotation design on N, P, K balances on organic farms using the NDICEA model
- Laurence G. Smith, Davide Tarsitano, Cairistiona F. E. Topp, Stephanie K. Jones, Catherine L. Gerrard, Bruce D. Pearce, Adrian G. Williams, Christine A. Watson
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- Renewable Agriculture and Food Systems / Volume 31 / Issue 5 / October 2016
- Published online by Cambridge University Press:
- 29 October 2015, pp. 471-484
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The dynamic model Nitrogen Dynamics in Crop rotations in Ecological Agriculture (NDICEA) was used to assess the nitrogen (N), phosphorus (P) and potassium (K) balance of long-term organic cropping trials and typical organic crop rotations on a range of soil types and rainfall zones in the UK. The measurements of soil N taken at each of the organic trial sites were also used to assess the performance of NDICEA. The modeled outputs compared well to recorded soil N levels, with relatively small error margins. NDICEA therefore seems to be a useful tool for UK organic farmers. The modeling of typical organic rotations has shown that positive N balances can be achieved, although negative N balances can occur under high rainfall conditions and on lighter soil types as a result of leaching. The analysis and modeling also showed that some organic cropping systems rely on imported sources of P and K to maintain an adequate balance and large deficits of both nutrients are apparent in stockless systems. Although the K deficits could be addressed through the buffering capacity of minerals, the amount available for crop uptake will depend on the type and amount of minerals present, current cropping and fertilization practices and the climatic environment. A P deficit represents a more fundamental problem for the maintenance of crop yields and the organic sector currently relies on mined sources of P which represents a fundamental conflict with the International Federation of Organic Agriculture Movements organic principles.
Contributors
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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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Reducing youth internalizing symptoms: Effects of a family-based preventive intervention on parental guilt induction and youth cognitive style
- Laura G. McKee, Justin Parent, Rex Forehand, Aaron Rakow, Kelly H. Watson, Jennifer P. Dunbar, Michelle M. Reising, Emily Hardcastle, Bruce E. Compas
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- Development and Psychopathology / Volume 26 / Issue 2 / May 2014
- Published online by Cambridge University Press:
- 17 January 2014, pp. 319-332
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This study utilized structural equation modeling to examine the associations among parental guilt induction (a form of psychological control), youth cognitive style, and youth internalizing symptoms, with parents and youth participating in a randomized controlled trial of a family-based group cognitive–behavioral preventive intervention targeting families with a history of caregiver depression. The authors present separate models utilizing parent report and youth report of internalizing symptoms. Findings suggest that families in the active condition (family-based group cognitive–behavioral group) relative to the comparison condition showed a significant decline in parent use of guilt induction at the conclusion of the intervention (6 months postbaseline). Furthermore, reductions in parental guilt induction at 6 months were associated with significantly lower levels of youth negative cognitive style at 12 months. Finally, reductions in parental use of guilt induction were associated with lower youth internalizing symptoms 1 year following the conclusion of the intervention (18 months postbaseline).
Narrative and procedural discourse in temporal lobe epilepsy
- BRIAN BELL, CHRISTIAN DOW, E. RYANN WATSON, AUSTIN WOODARD, BRUCE HERMANN, MICHAEL SEIDENBERG
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- Journal of the International Neuropsychological Society / Volume 9 / Issue 5 / July 2003
- Published online by Cambridge University Press:
- 01 July 2003, pp. 733-739
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It is well established that some individuals with temporal lobe epilepsy (TLE) demonstrate language deficits at the single word level. However, discourse production rarely has been examined quantitatively within this group. This study compared adult TLE patients with an early seizure onset (≤ age 14 years, n = 27) to a control group (n = 28) on narrative and procedural discourse tasks. As a group, the TLE patients performed normally on the procedural discourse task, but differed significantly from the controls on several narrative discourse variables. At the individual level, 30% of the TLE patients versus 4% of the controls demonstrated impaired discourse ability (p < .01). Within this early onset TLE group, discourse performance was not associated with demographic or seizure history variables. Considering the cognitive domain, discourse performance correlated significantly with working memory. In summary, mild discourse dysfunction was present in a significant minority of early onset TLE patients, but this deficit was not closely associated with other language measures. Discourse ability and its neuropsychological, neuroanatomical and conversational speech correlates deserve further study in TLE patients. (JINS, 2003, 9, 733–739.)
Dissolution, growth and survival of zircons during crustal fusion: kinetic principals, geological models and implications for isotopic inheritance
- E. Bruce Watson
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- Transactions of the Royal Society of Edinburgh: Earth Sciences / Volume 87 / Issue 1-2 / 1996
- Published online by Cambridge University Press:
- 03 November 2011, pp. 43-56
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- 1996
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Finite difference numerical simulations were used to characterise the rates of diffusion-controlled dissolution and growth of zircon in melts of granitic composition under geologically realistic conditions. The simulations incorporated known solubility and Zr diffusivity relationships for melts containing 3 wt% dissolved H2O and were carried out in both one and thre dimensions under conditions of constant temperature, linearly time-dependent temperature and for a variety of host system thermal histories. The rate of zircon dissolution at constant temperature depends systematically on time (t½−12;), temperature (exp T−1) and degree of undersaturation of the melt with respect to zircon (in ppm Zr). Linear dissolution and growth rates fall in the range 10−19 10−15 cm s−1 at temperatures of 650-850°C. Radial rates are strongly dependent on crystal size (varying in inverse proportion to the radius, r): for r>30 μm, dissolution and growth rates fall between 10−17 and 10−13 cm s−1. During crustal magmatism, the chances of survival for relict cores of protolith zircons depend on several factors, the most important of which are: the initial radius of the zircon; the intensity and duration of the magmatic event; and the volume of the local melt reservoir with which the zircon interacts. In general, only the largest protolith zircons (>120 μm radius) are likely to survive magmatic events exceeding 850°C. Conversely, only the smallest zircons (<50 μm radius) are likely to be completely consumed during low-temperature anatexis (i.e. not exceeding ≍700°C).
The effects of stirring the zircon-melt system are unimportant to dissolution and growth behaviour; except under circumstances of extreme shearing (e.g. filter pressing?), zircon dissolution is controlled by diffusion of Zr in the melt.
Perspectives on the source, segregation and transport of granitoid magmas
- Calvin F. Miller, E. Bruce Watson, T. Mark Harrison
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- Journal:
- Transactions of the Royal Society of Edinburgh: Earth Sciences / Volume 79 / Issue 2-3 / 1988
- Published online by Cambridge University Press:
- 03 November 2011, pp. 135-156
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- 1988
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The pursuit of a comprehensive theory for the origin and evolution of granitoids is hindered by our incomplete understanding of the nature of the source and the mechanisms by which the magma is segregated and transported. This paper is a collection of three largely independent and necessarily incomplete perspectives on these outstanding issues. Lower to mid-crustal regions, which contain the principal source material for granitoid magmas, are highly heterogeneous. Consideration of available transfer mechanisms suggests that (1) this heterogeneity survives all foreseeable lower crustal processes; (2) closure is on very different scales for different chemical systems (e.g. Pb, Nd, Sr and O isotopes); in almost all cases, however, closure scale is much smaller than the scale of magma extraction zones for plutons; and (3) pluton-wide homogenisation of magmas by diffusion is precluded by low diffusivities in felsic melts. Thus, granitoid magmas begin life as aggregates of small, isolated chemical domains; homogenisation occurs only through (and on the scale of) effective stirring by convection. Because of variability in local conditions as well as in bulk composition, crustal regions undergoing anatexis must be patchworks with variable melt fractions and melt compositions. The way in which magma is extracted from and coalesces with this patchwork exerts a critical influence on the nature of granitoid magmas. Decoupling and unusual coupling of compositional parameters and isotopic heterogeneity within plutons are to be expected in crust-derived granitoids and do not require contamination. Granites image their sources, but these sources are ill-defined and do not correspond to simple, easily-recognised materials. Extent and patterns of heterogeneity remaining in crystallised plutons may be effective indicators of the ascent process.
The efforts of materials scientists in characterising the nature and evolution of solid-phase interconnectivity in partially-molten materials may offer some insights into crustal magmatic processes. In particular, the rheological properties of partially-molten crustal rocks are probably strongly affected by the contiguity of the solid grains in the system (i.e. the fraction of their surface area that is shared with other grains). Theory and experimental data for simple alloy systems reveal that contiguity depends principally upon melt fraction and upon the characteristic wetting angle (θ) of the system. Measured θ's in granitoids (∼50° on average) imply contiguities as high as ∼0·2 for melt fractions of 0·5 or greater. This value in turn suggests that, at least under static conditions, a continuous skeleton of solid grains is maintained to quite high degrees of melting in the crust. Consequently, regions consisting of 50% or more of melt can, in principle, maintain not only high yield strength, but also high viscosity (provided the strain rate is sufficiently low to avoid disrupting contiguity).
Despite the fact that on some time scale the continuous solid skeleton of a partially-molten region resists deformation, it is itself subject to textural evolution that could lead to the upward migration of melt. Occasional detachment of grains from the skeleton and subsequent “microsettling” within the partially-molten column may lead eventually to compaction of the solid (without plastic deformation) and net upward displacement of melt.
Proposed granite transport mechanisms are discussed, although several are viewed as having historical interest only. In the absence of tectonic transport, diapirism appears to be the most compelling of these processes. However, considerable diversity exists in the literature regarding a pivotal requirement for this mechanism. Structural studies have tended to conclude that the granite diapir must be highly crystallised in order to ascend, whereas results of physical modelling yield contradictory results. For ascent to occur in these models, the magmas must be sufficiently fluid to allow convective circulation. Indeed, heat loss associated with diapirism is so efficient as to be a significant restriction on overall ascent. The resolution of these contrasting views appears to be that they reflect different phases of the ascent/emplacement continuum. Understanding the emplacement history of a southeastern Australian pluton allows assessment, via the diapir model, of the flow properties of the rock within the deformation aureole. Results suggest rock viscosities about an order of magnitude lower than those predicted by laboratory experiments, perhaps reflecting difficulties in reproducing natural conditions in the laboratory.