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Spatial working memory performance in people with obsessive–compulsive disorder, their unaffected first-degree relatives and healthy controls
- Stephan Heinzel, Katharina Bey, Rosa Grützmann, Julia Klawohn, Christian Kaufmann, Leonhard Lennertz, Michael Wagner, Norbert Kathmann, Anja Riesel
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- Journal:
- BJPsych Open / Volume 7 / Issue 6 / November 2021
- Published online by Cambridge University Press:
- 15 November 2021, e208
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Studies have shown that people with obsessive–compulsive disorder (OCD) have impairments in spatial working memory (SWM) performance. However, it remains unclear whether this deficit represents a cognitive endophenotype preceding symptoms or a correlate of OCD. We investigated SWM in 69 people with OCD, 77 unaffected first-degree relatives of people with OCD and 106 healthy control participants. Taking age effects into account, SWM performance was best in healthy controls, intermediate in relatives and worst in OCD participants. However, since performance did not differ significantly between healthy controls and relatives, our study does not fully support SWM performance as a core cognitive endophenotype of OCD.
Error-related brain activity as a transdiagnostic endophenotype for obsessive-compulsive disorder, anxiety and substance use disorder
- Anja Riesel, Julia Klawohn, Rosa Grützmann, Christian Kaufmann, Stephan Heinzel, Katharina Bey, Leonhard Lennertz, Michael Wagner, Norbert Kathmann
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- Journal:
- Psychological Medicine / Volume 49 / Issue 7 / May 2019
- Published online by Cambridge University Press:
- 12 February 2019, pp. 1207-1217
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Background
Increased neural error-signals have been observed in obsessive-compulsive disorder (OCD), anxiety disorders, and inconsistently in depression. Reduced neural error-signals have been observed in substance use disorders (SUD). Thus, alterations in error-monitoring are proposed as a transdiagnostic endophenotype. To strengthen this notion, data from unaffected individuals with a family history for the respective disorders are needed.
MethodsThe error-related negativity (ERN) as a neural indicator of error-monitoring was measured during a flanker task from 117 OCD patients, 50 unaffected first-degree relatives of OCD patients, and 130 healthy comparison participants. Family history information indicated, that 76 healthy controls were free of a family history for psychopathology, whereas the remaining had first-degree relatives with depression (n = 28), anxiety (n = 27), and/or SUD (n = 27).
ResultsIncreased ERN amplitudes were found in OCD patients and unaffected first-degree relatives of OCD patients. In addition, unaffected first-degree relatives of individuals with anxiety disorders were also characterized by increased ERN amplitudes, whereas relatives of individuals with SUD showed reduced amplitudes.
ConclusionsAlterations in neural error-signals in unaffected first-degree relatives with a family history of OCD, anxiety, or SUD support the utility of the ERN as a transdiagnostic endophenotype. Reduced neural error-signals may indicate vulnerability for under-controlled behavior and risk for substance use, whereas a harm- or error-avoidant response style and vulnerability for OCD and anxiety appears to be associated with increased ERN. This adds to findings suggesting a common neurobiological substrate across psychiatric disorders involving the anterior cingulate cortex and deficits in cognitive control.
Amygdala–prefrontal connectivity during appraisal of symptom-related stimuli in obsessive–compulsive disorder
- Sandra Paul, Jan C. Beucke, Christian Kaufmann, Anna Mersov, Stephan Heinzel, Norbert Kathmann, Daniela Simon
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- Journal:
- Psychological Medicine / Volume 49 / Issue 2 / January 2019
- Published online by Cambridge University Press:
- 06 April 2018, pp. 278-286
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Background
Cognitive models of obsessive–compulsive disorder (OCD) posit dysfunctional appraisal of disorder-relevant stimuli in patients, suggesting disturbances in the processes relying on amygdala–prefrontal connectivity. Recent neuroanatomical models add to the traditional view of dysfunction in corticostriatal circuits by proposing alterations in an affective circuit including amygdala–prefrontal connections. However, abnormalities in amygdala–prefrontal coupling during symptom provocation, and particularly during conditions that require stimulus appraisal, remain to be demonstrated directly.
MethodsAmygdala–prefrontal connectivity was examined in unmedicated OCD patients during appraisal (v. distraction) of symptom-provoking stimuli compared with an emotional control condition. Subsequent analyses tested whether hypothesized connectivity alterations could be also identified during passive viewing and the resting state in two independent samples.
ResultsDuring symptom provocation, reductions in positive coupling between amygdala and orbitofrontal cortex were observed in OCD patients relative to healthy control participants during appraisal and passive viewing of OCD-relevant stimuli, whereas abnormally high amygdala–ventromedial prefrontal cortex coupling was found when appraisal was distracted by a secondary task. In contrast, there were no group differences in amygdala connectivity at rest.
ConclusionsOur finding of abnormal amygdala–prefrontal connectivity during appraisal of symptom-related (relative to generally aversive) stimuli is consistent with the involvement of affective circuits in the functional neuroanatomy of OCD. Aberrant connectivity can be assumed to impact stimulus appraisal and emotion regulation, but might also relate to fear extinction deficits, which have recently been described in OCD. Taken together, we propose to integrate abnormalities in amygdala–prefrontal coupling in affective models of OCD.
Default mode network subsystem alterations in obsessive–compulsive disorder
- Jan C. Beucke, Jorge Sepulcre, Mark C. Eldaief, Miriam Sebold, Norbert Kathmann, Christian Kaufmann
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- Journal:
- The British Journal of Psychiatry / Volume 205 / Issue 5 / November 2014
- Published online by Cambridge University Press:
- 02 January 2018, pp. 376-382
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- November 2014
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Background
Although neurobiological models of obsessive–compulsive disorder (OCD) traditionally emphasise the central role of corticostriatal brain regions, studies of default mode network integrity have garnered increasing interest, but have produced conflicting results.
AimsTo resolve these discrepant findings by examining the integrity of default mode network subsystems in OCD.
MethodComparison of seed-based resting-state functional connectivity of 11 default mode network components between 46 patients with OCD and 46 controls using functional magnetic resonance imaging.
ResultsSignificantly reduced connectivity within the dorsal medial prefrontal cortex self subsystem was identified in the OCD group, and remained significant after controlling for medication status and life-time history of affective disorders. Further, greater connectivity between the self subsystem and salience and attention networks was observed.
ConclusionsResults indicate that people with OCD show abnormalities in a neural system previously associated with self-referential processing in healthy individuals, and suggest the need for examination of dynamic interactions between this default mode network subsystem and other large-scale networks in this disorder.
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- By Kern Alexander, Thomas Cottier, Isabel Feichtner, François Gianviti, Mario Giovanoli, Bernard Hoekman, Robert Howse, Christine Kaufmann, Mathias Kende, Markus Krajewski, Rosa M. Lastra, Jean-Victor Louis, Federico Lupo-Pasini, Iain Macneil, Gabrielle Z. Marceau, Juan Marchetti, John J. Maughan, Ernst-Ulrich Petersmann, Nadia Rendak, Michele Ruta, Lucía Satragno, Robert Teh, Christian Tietje, Annamaria Viterbo, Rolf H. Weber, Claus D. Zimmermann
- Edited by Thomas Cottier, Universität Bern, Switzerland, Rosa M. Lastra, Queen Mary University of London, Christian Tietje, Martin Luther-Universität Halle-Wittenberg, Germany
- Edited in association with Lucía Satragno, Universität Bern, Switzerland
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- The Rule of Law in Monetary Affairs
- Published online:
- 05 September 2014
- Print publication:
- 29 August 2014, pp x-xii
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Identification of field-caught Culicoides biting midges using matrix-assisted laser desorption/ionization time of flight mass spectrometry
- CHRISTIAN KAUFMANN, FRANCIS SCHAFFNER, DOMINIK ZIEGLER, VALENTIN PFLÜGER, ALEXANDER MATHIS
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- Journal:
- Parasitology / Volume 139 / Issue 2 / February 2012
- Published online by Cambridge University Press:
- 19 October 2011, pp. 248-258
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Culicoides biting midges are of great importance as vectors of pathogens and elicitors of allergy. As an alternative for the identification of these tiny insects, matrix-assisted laser desorption/ionization time of flight mass spectrometry (MALDI-TOF MS) was evaluated. Protein mass fingerprints were determined for 4–5 field-caught reference (genetically confirmed) individuals of 12 Culicoides species from Switzerland, C. imicola from France, laboratory-reared C. nubeculosus and a non-biting midge. Reproducibility and accuracy of the database was tested in a validation study by analysing 108 mostly field-caught target Culicoides midges and 3 specimens from a non-target species. A reference database of biomarker mass sets containing between 24 and 38 masses for the different species could be established. Automated database-based identification was achieved for 101 of the 108 specimens. The remaining 7 midges required manual full comparison with the reference spectra yielding correct identification for 6 specimens and an ambiguous result for the seventh individual. Specimens of the non-target species did not yield identification. Protein profiling by MALDI-TOF, which is compatible with morphological and genetic identification of specimens, can be used as an alternative, quick and inexpensive tool to accurately identify Culicoides biting midges collected in the field.
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- By Rose Teteki Abbey, K. C. Abraham, David Tuesday Adamo, LeRoy H. Aden, Efrain Agosto, Victor Aguilan, Gillian T. W. Ahlgren, Charanjit Kaur AjitSingh, Dorothy B E A Akoto, Giuseppe Alberigo, Daniel E. Albrecht, Ruth Albrecht, Daniel O. Aleshire, Urs Altermatt, Anand Amaladass, Michael Amaladoss, James N. Amanze, Lesley G. Anderson, Thomas C. Anderson, Victor Anderson, Hope S. Antone, María Pilar Aquino, Paula Arai, Victorio Araya Guillén, S. Wesley Ariarajah, Ellen T. Armour, Brett Gregory Armstrong, Atsuhiro Asano, Naim Stifan Ateek, Mahmoud Ayoub, John Alembillah Azumah, Mercedes L. García Bachmann, Irena Backus, J. Wayne Baker, Mieke Bal, Lewis V. Baldwin, William Barbieri, António Barbosa da Silva, David Basinger, Bolaji Olukemi Bateye, Oswald Bayer, Daniel H. Bays, Rosalie Beck, Nancy Elizabeth Bedford, Guy-Thomas Bedouelle, Chorbishop Seely Beggiani, Wolfgang Behringer, Christopher M. Bellitto, Byard Bennett, Harold V. Bennett, Teresa Berger, Miguel A. Bernad, Henley Bernard, Alan E. Bernstein, Jon L. Berquist, Johannes Beutler, Ana María Bidegain, Matthew P. Binkewicz, Jennifer Bird, Joseph Blenkinsopp, Dmytro Bondarenko, Paulo Bonfatti, Riet en Pim Bons-Storm, Jessica A. Boon, Marcus J. Borg, Mark Bosco, Peter C. Bouteneff, François Bovon, William D. Bowman, Paul S. Boyer, David Brakke, Richard E. Brantley, Marcus Braybrooke, Ian Breward, Ênio José da Costa Brito, Jewel Spears Brooker, Johannes Brosseder, Nicholas Canfield Read Brown, Robert F. Brown, Pamela K. Brubaker, Walter Brueggemann, Bishop Colin O. Buchanan, Stanley M. Burgess, Amy Nelson Burnett, J. Patout Burns, David B. Burrell, David Buttrick, James P. Byrd, Lavinia Byrne, Gerado Caetano, Marcos Caldas, Alkiviadis Calivas, William J. Callahan, Salvatore Calomino, Euan K. Cameron, William S. Campbell, Marcelo Ayres Camurça, Daniel F. Caner, Paul E. Capetz, Carlos F. Cardoza-Orlandi, Patrick W. Carey, Barbara Carvill, Hal Cauthron, Subhadra Mitra Channa, Mark D. Chapman, James H. Charlesworth, Kenneth R. Chase, Chen Zemin, Luciano Chianeque, Philip Chia Phin Yin, Francisca H. Chimhanda, Daniel Chiquete, John T. Chirban, Soobin Choi, Robert Choquette, Mita Choudhury, Gerald Christianson, John Chryssavgis, Sejong Chun, Esther Chung-Kim, Charles M. A. Clark, Elizabeth A. Clark, Sathianathan Clarke, Fred Cloud, John B. Cobb, W. Owen Cole, John A Coleman, John J. Collins, Sylvia Collins-Mayo, Paul K. Conkin, Beth A. Conklin, Sean Connolly, Demetrios J. Constantelos, Michael A. Conway, Paula M. Cooey, Austin Cooper, Michael L. Cooper-White, Pamela Cooper-White, L. William Countryman, Sérgio Coutinho, Pamela Couture, Shannon Craigo-Snell, James L. Crenshaw, David Crowner, Humberto Horacio Cucchetti, Lawrence S. Cunningham, Elizabeth Mason Currier, Emmanuel Cutrone, Mary L. Daniel, David D. Daniels, Robert Darden, Rolf Darge, Isaiah Dau, Jeffry C. Davis, Jane Dawson, Valentin Dedji, John W. de Gruchy, Paul DeHart, Wendy J. Deichmann Edwards, Miguel A. De La Torre, George E. Demacopoulos, Thomas de Mayo, Leah DeVun, Beatriz de Vasconcellos Dias, Dennis C. Dickerson, John M. Dillon, Luis Miguel Donatello, Igor Dorfmann-Lazarev, Susanna Drake, Jonathan A. Draper, N. Dreher Martin, Otto Dreydoppel, Angelyn Dries, A. J. Droge, Francis X. D'Sa, Marilyn Dunn, Nicole Wilkinson Duran, Rifaat Ebied, Mark J. Edwards, William H. Edwards, Leonard H. Ehrlich, Nancy L. Eiesland, Martin Elbel, J. Harold Ellens, Stephen Ellingson, Marvin M. Ellison, Robert Ellsberg, Jean Bethke Elshtain, Eldon Jay Epp, Peter C. Erb, Tassilo Erhardt, Maria Erling, Noel Leo Erskine, Gillian R. Evans, Virginia Fabella, Michael A. Fahey, Edward Farley, Margaret A. Farley, Wendy Farley, Robert Fastiggi, Seena Fazel, Duncan S. Ferguson, Helwar Figueroa, Paul Corby Finney, Kyriaki Karidoyanes FitzGerald, Thomas E. FitzGerald, John R. Fitzmier, Marie Therese Flanagan, Sabina Flanagan, Claude Flipo, Ronald B. Flowers, Carole Fontaine, David Ford, Mary Ford, Stephanie A. Ford, Jim Forest, William Franke, Robert M. Franklin, Ruth Franzén, Edward H. Friedman, Samuel Frouisou, Lorelei F. Fuchs, Jojo M. Fung, Inger Furseth, Richard R. Gaillardetz, Brandon Gallaher, China Galland, Mark Galli, Ismael García, Tharscisse Gatwa, Jean-Marie Gaudeul, Luis María Gavilanes del Castillo, Pavel L. Gavrilyuk, Volney P. Gay, Metropolitan Athanasios Geevargis, Kondothra M. George, Mary Gerhart, Simon Gikandi, Maurice Gilbert, Michael J. Gillgannon, Verónica Giménez Beliveau, Terryl Givens, Beth Glazier-McDonald, Philip Gleason, Menghun Goh, Brian Golding, Bishop Hilario M. Gomez, Michelle A. Gonzalez, Donald K. Gorrell, Roy Gottfried, Tamara Grdzelidze, Joel B. Green, Niels Henrik Gregersen, Cristina Grenholm, Herbert Griffiths, Eric W. Gritsch, Erich S. Gruen, Christoffer H. Grundmann, Paul H. Gundani, Jon P. Gunnemann, Petre Guran, Vidar L. Haanes, Jeremiah M. Hackett, Getatchew Haile, Douglas John Hall, Nicholas Hammond, Daphne Hampson, Jehu J. Hanciles, Barry Hankins, Jennifer Haraguchi, Stanley S. Harakas, Anthony John Harding, Conrad L. Harkins, J. William Harmless, Marjory Harper, Amir Harrak, Joel F. Harrington, Mark W. Harris, Susan Ashbrook Harvey, Van A. Harvey, R. Chris Hassel, Jione Havea, Daniel Hawk, Diana L. Hayes, Leslie Hayes, Priscilla Hayner, S. Mark Heim, Simo Heininen, Richard P. Heitzenrater, Eila Helander, David Hempton, Scott H. Hendrix, Jan-Olav Henriksen, Gina Hens-Piazza, Carter Heyward, Nicholas J. Higham, David Hilliard, Norman A. Hjelm, Peter C. Hodgson, Arthur Holder, M. Jan Holton, Dwight N. Hopkins, Ronnie Po-chia Hsia, Po-Ho Huang, James Hudnut-Beumler, Jennifer S. Hughes, Leonard M. Hummel, Mary E. Hunt, Laennec Hurbon, Mark Hutchinson, Susan E. Hylen, Mary Beth Ingham, H. Larry Ingle, Dale T. Irvin, Jon Isaak, Paul John Isaak, Ada María Isasi-Díaz, Hans Raun Iversen, Margaret C. Jacob, Arthur James, Maria Jansdotter-Samuelsson, David Jasper, Werner G. Jeanrond, Renée Jeffery, David Lyle Jeffrey, Theodore W. Jennings, David H. Jensen, Robin Margaret Jensen, David Jobling, Dale A. Johnson, Elizabeth A. Johnson, Maxwell E. Johnson, Sarah Johnson, Mark D. Johnston, F. Stanley Jones, James William Jones, John R. Jones, Alissa Jones Nelson, Inge Jonsson, Jan Joosten, Elizabeth Judd, Mulambya Peggy Kabonde, Robert Kaggwa, Sylvester Kahakwa, Isaac Kalimi, Ogbu U. Kalu, Eunice Kamaara, Wayne C. Kannaday, Musimbi Kanyoro, Veli-Matti Kärkkäinen, Frank Kaufmann, Léon Nguapitshi Kayongo, Richard Kearney, Alice A. Keefe, Ralph Keen, Catherine Keller, Anthony J. Kelly, Karen Kennelly, Kathi Lynn Kern, Fergus Kerr, Edward Kessler, George Kilcourse, Heup Young Kim, Kim Sung-Hae, Kim Yong-Bock, Kim Yung Suk, Richard King, Thomas M. King, Robert M. Kingdon, Ross Kinsler, Hans G. Kippenberg, Cheryl A. Kirk-Duggan, Clifton Kirkpatrick, Leonid Kishkovsky, Nadieszda Kizenko, Jeffrey Klaiber, Hans-Josef Klauck, Sidney Knight, Samuel Kobia, Robert Kolb, Karla Ann Koll, Heikki Kotila, Donald Kraybill, Philip D. W. Krey, Yves Krumenacker, Jeffrey Kah-Jin Kuan, Simanga R. Kumalo, Peter Kuzmic, Simon Shui-Man Kwan, Kwok Pui-lan, André LaCocque, Stephen E. Lahey, John Tsz Pang Lai, Emiel Lamberts, Armando Lampe, Craig Lampe, Beverly J. Lanzetta, Eve LaPlante, Lizette Larson-Miller, Ariel Bybee Laughton, Leonard Lawlor, Bentley Layton, Robin A. Leaver, Karen Lebacqz, Archie Chi Chung Lee, Marilyn J. Legge, Hervé LeGrand, D. L. LeMahieu, Raymond Lemieux, Bill J. Leonard, Ellen M. Leonard, Outi Leppä, Jean Lesaulnier, Nantawan Boonprasat Lewis, Henrietta Leyser, Alexei Lidov, Bernard Lightman, Paul Chang-Ha Lim, Carter Lindberg, Mark R. Lindsay, James R. Linville, James C. Livingston, Ann Loades, David Loades, Jean-Claude Loba-Mkole, Lo Lung Kwong, Wati Longchar, Eleazar López, David W. Lotz, Andrew Louth, Robin W. Lovin, William Luis, Frank D. Macchia, Diarmaid N. J. MacCulloch, Kirk R. MacGregor, Marjory A. MacLean, Donald MacLeod, Tomas S. Maddela, Inge Mager, Laurenti Magesa, David G. Maillu, Fortunato Mallimaci, Philip Mamalakis, Kä Mana, Ukachukwu Chris Manus, Herbert Robinson Marbury, Reuel Norman Marigza, Jacqueline Mariña, Antti Marjanen, Luiz C. L. Marques, Madipoane Masenya (ngwan'a Mphahlele), Caleb J. D. Maskell, Steve Mason, Thomas Massaro, Fernando Matamoros Ponce, András Máté-Tóth, Odair Pedroso Mateus, Dinis Matsolo, Fumitaka Matsuoka, John D'Arcy May, Yelena Mazour-Matusevich, Theodore Mbazumutima, John S. McClure, Christian McConnell, Lee Martin McDonald, Gary B. McGee, Thomas McGowan, Alister E. McGrath, Richard J. McGregor, John A. McGuckin, Maud Burnett McInerney, Elsie Anne McKee, Mary B. McKinley, James F. McMillan, Ernan McMullin, Kathleen E. McVey, M. Douglas Meeks, Monica Jyotsna Melanchthon, Ilie Melniciuc-Puica, Everett Mendoza, Raymond A. Mentzer, William W. Menzies, Ina Merdjanova, Franziska Metzger, Constant J. Mews, Marvin Meyer, Carol Meyers, Vasile Mihoc, Gunner Bjerg Mikkelsen, Maria Inêz de Castro Millen, Clyde Lee Miller, Bonnie J. Miller-McLemore, Alexander Mirkovic, Paul Misner, Nozomu Miyahira, R. W. L. Moberly, Gerald Moede, Aloo Osotsi Mojola, Sunanda Mongia, Rebeca Montemayor, James Moore, Roger E. Moore, Craig E. Morrison O.Carm, Jeffry H. Morrison, Keith Morrison, Wilson J. Moses, Tefetso Henry Mothibe, Mokgethi Motlhabi, Fulata Moyo, Henry Mugabe, Jesse Ndwiga Kanyua Mugambi, Peggy Mulambya-Kabonde, Robert Bruce Mullin, Pamela Mullins Reaves, Saskia Murk Jansen, Heleen L. Murre-Van den Berg, Augustine Musopole, Isaac M. T. Mwase, Philomena Mwaura, Cecilia Nahnfeldt, Anne Nasimiyu Wasike, Carmiña Navia Velasco, Thulani Ndlazi, Alexander Negrov, James B. Nelson, David G. Newcombe, Carol Newsom, Helen J. Nicholson, George W. E. Nickelsburg, Tatyana Nikolskaya, Damayanthi M. A. Niles, Bertil Nilsson, Nyambura Njoroge, Fidelis Nkomazana, Mary Beth Norton, Christian Nottmeier, Sonene Nyawo, Anthère Nzabatsinda, Edward T. Oakes, Gerald O'Collins, Daniel O'Connell, David W. Odell-Scott, Mercy Amba Oduyoye, Kathleen O'Grady, Oyeronke Olajubu, Thomas O'Loughlin, Dennis T. Olson, J. Steven O'Malley, Cephas N. Omenyo, Muriel Orevillo-Montenegro, César Augusto Ornellas Ramos, Agbonkhianmeghe E. Orobator, Kenan B. Osborne, Carolyn Osiek, Javier Otaola Montagne, Douglas F. Ottati, Anna May Say Pa, Irina Paert, Jerry G. Pankhurst, Aristotle Papanikolaou, Samuele F. Pardini, Stefano Parenti, Peter Paris, Sung Bae Park, Cristián G. Parker, Raquel Pastor, Joseph Pathrapankal, Daniel Patte, W. Brown Patterson, Clive Pearson, Keith F. Pecklers, Nancy Cardoso Pereira, David Horace Perkins, Pheme Perkins, Edward N. Peters, Rebecca Todd Peters, Bishop Yeznik Petrossian, Raymond Pfister, Peter C. Phan, Isabel Apawo Phiri, William S. F. Pickering, Derrick G. Pitard, William Elvis Plata, Zlatko Plese, John Plummer, James Newton Poling, Ronald Popivchak, Andrew Porter, Ute Possekel, James M. Powell, Enos Das Pradhan, Devadasan Premnath, Jaime Adrían Prieto Valladares, Anne Primavesi, Randall Prior, María Alicia Puente Lutteroth, Eduardo Guzmão Quadros, Albert Rabil, Laurent William Ramambason, Apolonio M. Ranche, Vololona Randriamanantena Andriamitandrina, Lawrence R. Rast, Paul L. Redditt, Adele Reinhartz, Rolf Rendtorff, Pål Repstad, James N. Rhodes, John K. Riches, Joerg Rieger, Sharon H. Ringe, Sandra Rios, Tyler Roberts, David M. Robinson, James M. Robinson, Joanne Maguire Robinson, Richard A. H. Robinson, Roy R. Robson, Jack B. Rogers, Maria Roginska, Sidney Rooy, Rev. Garnett Roper, Maria José Fontelas Rosado-Nunes, Andrew C. Ross, Stefan Rossbach, François Rossier, John D. Roth, John K. Roth, Phillip Rothwell, Richard E. Rubenstein, Rosemary Radford Ruether, Markku Ruotsila, John E. Rybolt, Risto Saarinen, John Saillant, Juan Sanchez, Wagner Lopes Sanchez, Hugo N. Santos, Gerhard Sauter, Gloria L. Schaab, Sandra M. Schneiders, Quentin J. Schultze, Fernando F. Segovia, Turid Karlsen Seim, Carsten Selch Jensen, Alan P. F. Sell, Frank C. Senn, Kent Davis Sensenig, Damían Setton, Bal Krishna Sharma, Carolyn J. Sharp, Thomas Sheehan, N. Gerald Shenk, Christian Sheppard, Charles Sherlock, Tabona Shoko, Walter B. Shurden, Marguerite Shuster, B. Mark Sietsema, Batara Sihombing, Neil Silberman, Clodomiro Siller, Samuel Silva-Gotay, Heikki Silvet, John K. Simmons, Hagith Sivan, James C. Skedros, Abraham Smith, Ashley A. Smith, Ted A. Smith, Daud Soesilo, Pia Søltoft, Choan-Seng (C. S.) Song, Kathryn Spink, Bryan Spinks, Eric O. Springsted, Nicolas Standaert, Brian Stanley, Glen H. Stassen, Karel Steenbrink, Stephen J. Stein, Andrea Sterk, Gregory E. Sterling, Columba Stewart, Jacques Stewart, Robert B. Stewart, Cynthia Stokes Brown, Ken Stone, Anne Stott, Elizabeth Stuart, Monya Stubbs, Marjorie Hewitt Suchocki, David Kwang-sun Suh, Scott W. Sunquist, Keith Suter, Douglas Sweeney, Charles H. Talbert, Shawqi N. Talia, Elsa Tamez, Joseph B. Tamney, Jonathan Y. Tan, Yak-Hwee Tan, Kathryn Tanner, Feiya Tao, Elizabeth S. Tapia, Aquiline Tarimo, Claire Taylor, Mark Lewis Taylor, Bishop Abba Samuel Wolde Tekestebirhan, Eugene TeSelle, M. Thomas Thangaraj, David R. Thomas, Andrew Thornley, Scott Thumma, Marcelo Timotheo da Costa, George E. “Tink” Tinker, Ola Tjørhom, Karen Jo Torjesen, Iain R. Torrance, Fernando Torres-Londoño, Archbishop Demetrios [Trakatellis], Marit Trelstad, Christine Trevett, Phyllis Trible, Johannes Tromp, Paul Turner, Robert G. Tuttle, Archbishop Desmond Tutu, Peter Tyler, Anders Tyrberg, Justin Ukpong, Javier Ulloa, Camillus Umoh, Kristi Upson-Saia, Martina Urban, Monica Uribe, Elochukwu Eugene Uzukwu, Richard Vaggione, Gabriel Vahanian, Paul Valliere, T. J. Van Bavel, Steven Vanderputten, Peter Van der Veer, Huub Van de Sandt, Louis Van Tongeren, Luke A. Veronis, Noel Villalba, Ramón Vinke, Tim Vivian, David Voas, Elena Volkova, Katharina von Kellenbach, Elina Vuola, Timothy Wadkins, Elaine M. Wainwright, Randi Jones Walker, Dewey D. Wallace, Jerry Walls, Michael J. Walsh, Philip Walters, Janet Walton, Jonathan L. Walton, Wang Xiaochao, Patricia A. Ward, David Harrington Watt, Herold D. Weiss, Laurence L. Welborn, Sharon D. Welch, Timothy Wengert, Traci C. West, Merold Westphal, David Wetherell, Barbara Wheeler, Carolinne White, Jean-Paul Wiest, Frans Wijsen, Terry L. Wilder, Felix Wilfred, Rebecca Wilkin, Daniel H. Williams, D. Newell Williams, Michael A. Williams, Vincent L. Wimbush, Gabriele Winkler, Anders Winroth, Lauri Emílio Wirth, James A. Wiseman, Ebba Witt-Brattström, Teofil Wojciechowski, John Wolffe, Kenman L. Wong, Wong Wai Ching, Linda Woodhead, Wendy M. Wright, Rose Wu, Keith E. Yandell, Gale A. Yee, Viktor Yelensky, Yeo Khiok-Khng, Gustav K. K. Yeung, Angela Yiu, Amos Yong, Yong Ting Jin, You Bin, Youhanna Nessim Youssef, Eliana Yunes, Robert Michael Zaller, Valarie H. Ziegler, Barbara Brown Zikmund, Joyce Ann Zimmerman, Aurora Zlotnik, Zhuo Xinping
- Edited by Daniel Patte, Vanderbilt University, Tennessee
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- Book:
- The Cambridge Dictionary of Christianity
- Published online:
- 05 August 2012
- Print publication:
- 20 September 2010, pp xi-xliv
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Natural invariant measures, divergence points and dimension in one-dimensional holomorphic dynamics
- WILLIAM INGLE, JACIE KAUFMANN, CHRISTIAN WOLF
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- Journal:
- Ergodic Theory and Dynamical Systems / Volume 29 / Issue 4 / August 2009
- Published online by Cambridge University Press:
- 01 August 2009, pp. 1235-1255
- Print publication:
- August 2009
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In this paper we discuss the dimension-theoretical properties of rational maps on the Riemann sphere. In particular, we study the existence and uniqueness of generalized physical measures for several classes of maps including hyperbolic, parabolic, non-recurrent and topological Collet–Eckmann maps. These measures have the property that their typical points have maximal Hausdorff dimension. On the other hand, we prove that the set of divergence points (the set of points which are non-typical for any invariant measure) also has maximal Hausdorff dimension. Finally, we prove that if (fa)a is a holomorphic family of stable rational maps, then the dimension d(fa) is a continuous and plurisubharmonic function of the parameter a. In particular, d(f) varies continuously and plurisubharmonically on an open and dense subset of Ratd, the space of all rational maps with degree d≥2.
Incorporation of Na in Low-Temperature Deposition of CIGS Flexible Solar Cells
- Hendrik Zachmann, Stefan Puttnins, Felix Daume, Andreas Rahm, Karsten Otte, Raquel Caballero, Christian A. Kaufmann, Tobias Eisenbarth, H.W. Schock
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1210 / 2009
- Published online by Cambridge University Press:
- 31 January 2011, 1210-Q03-02
- Print publication:
- 2009
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Different methods for Na incorporation are known for the use of Na-free substrates like stainless steel or polyimide foil. In this work Cu(In,Ga)Se2 (CIGS) absorber layers with different amounts of Na are investigated. The CIGS samples were prepared via a roll-to-roll deposition process with ion beam assistance (Solarion) and by a multi-stage low temperature co-evaporation process (HZB). Na was either incorporated via in-situ co-evaporation of NaF (for roll-to-roll deposition) or by a Na-containing precursor (for multi-stage deposition). With increasing amounts of Na an increase of VOC is observed for both deposition tech-niques. In contrast, within the deposition parameters used, jSC decreases with increasing Na amount for co-evaporation of NaF while it seems unaffected when using a NaF precursor layer. The elemental depth profiles of the different CIGS thin films were studied via secondary ion mass spectroscopy and were found to depend strongly on the deposition technique. It seems that beneficial effects of the addition of Na are independent of the method of in-corporation, even if the distribution of Na in the CIGS layer is different due to different methods of incorporation and CIGS deposition processes.
Enhanced Efficiency of CIGS Thin Film Solar Cells on Polyimide Substrates
- Raquel Caballero, Christian A. Kaufmann, Tobias Eisenbarth, Axel Eicke, Thomas Unold, Reiner Klenk, H.W. Schock
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1165 / 2009
- Published online by Cambridge University Press:
- 31 January 2011, 1165-M02-10
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- 2009
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The effect of the amount of Na present during the 3-stage growth of CIGS at very low temperature T2 on polyimide (PI) foils is studied. While at higher growth temperatures Na seems to impede In-Ga interdifussion, at very low temperatures it appears to further the process. An increase in Voc for a higher Na concentration can be explained by a higher net carrier concentration as measured by drive level capacitance profiling. Admittance spectroscopy measurements show shallow defects when the Na concentration increases. These results suggest that the main role of Na could be the passivation of InCu donor deep defect, in agreement with Wei's theory. Efficiencies of up to 15.1 % (0.5 cm2 active area with antireflection coating) and 13.6%, 14.1% (1 cm2 total and active area respectively without antireflection coating) for nominal T2=420° C were achieved on PI substrates so far.
CuGaSe2-Based Solar Cells with High Open Circuit Voltage
- Raquel Caballero, Susanne Siebentritt, Christian A. Kaufmann, Carola Kelch, Daniel Schweigert, Thomas Unold, Marin Rusu, Hans-Werner Schock, Martha Ch Lux-Steiner
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- Journal:
- MRS Online Proceedings Library Archive / Volume 1012 / 2007
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- 01 February 2011, 1012-Y12-38
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- 2007
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The objective of this work is to increase the open circuit voltage of CuGaSe2(CGS)-based solar cells without decreasing their efficiency. For that, the interface between the p-type CGS absorber and the n-type CdS/ZnO window layer is compared using three different recipes for the growth of the buffer layer. Results show the importance of the adaptation of the CdS buffer layer to the CuGaSe2 absorber film. A maximum open circuit voltage of 922 mV is achieved for the devices when using 60ºC as the chemical bath temperature and a low thiourea concentration. Drive-level capacitance profiling, external quantum efficiency and temperature dependent current-voltage measurements reveal a better quality of the CdS/CuGaSe2 interface for this buffer layer deposition conditions. Factors such as the larger depletion region width and the lower doping level, reducing the tunnelling component, are pointed out as responsible of the higher Voc.
Preferred Orientation, Grain Sizes and Grain Boundaries of Chalcopyrite-Type Thin Films
- Daniel Abou-Ras, Melanie Nichterwitz, Christian A. Kaufmann, Susan Schorr, Hans-Werner Schock
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- MRS Online Proceedings Library Archive / Volume 1012 / 2007
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- 01 February 2011, 1012-Y09-03
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- 2007
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Chalcopyrite-type thin films - CuInS2, CuInSe2, CuGaSe2, and Cu(In,Ga)Se2 - in various completed solar cells were studied in cross-section by means of electron-backscatter diffraction (EBSD). Valuable information on grain sizes, local grain orientations, film textures, and grain boundaries were extracted from the EBSD linescans and maps. The grain-size distributions from the chalcopyrite-type thin films can be represented well by lognormal distribution functions. The EBSD measurements on CuGaSe2 thin film reveal a <110> fiber texture, in good agreement with x-ray diffraction texture analysis performed on the same sample. The EBSD maps from all samples studied exhibit considerable twinning in the chalcopyrite-type thin films. Indeed, the most frequent types of grain boundaries in these thin films are (near) Σ3 60°-<221> and 71°-<110> twins. It is shown that rotational 180°-<221> twins (which are symmetrically equivalent to 71°-<110>) are more frequently found than anion- or cation-terminated 60°-<221> twin boundaries.
Sedimentary evolution of a Palaeozoic basin and ridge system: the Middle and Upper Devonian of the Ahnet and Mouydir (Algerian Sahara)
- JOBST WENDT, BERND KAUFMANN, ZDZISLAW BELKA, CHRISTIAN KLUG, STEFAN LUBESEDER
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- Journal:
- Geological Magazine / Volume 143 / Issue 3 / May 2006
- Published online by Cambridge University Press:
- 30 March 2006, pp. 269-299
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The Ahnet and Mouydir regions of southern Algeria are part of one of the world's largest, almost undeformed exposures of Palaeozoic rocks which exemplify a hitherto poorly known early Variscan development of a Devonian basin and ridge system. This area includes a series of intracratonic basins along the northern margin of the West African Craton which consists (from W to E) of the Reggane Basin, Azel Matti Ridge, Ahnet Basin, Foum Belrem Ridge and Mouydir Basin. The depositional and palaeogeographic interpretation is based on 71 sections in this region, which for the first time were biostratigraphically calibrated by means of conodonts, goniatites and brachiopods. The structural evolution during Devonian times was probably controlled by reactivation of ancient N–S- to NW–SE-running faults in the Precambrian basement, which caused differential subsidence and uplift of a previously largely unstructured siliciclastic shelf. A hiatus during Emsian times indicates widespread emergence during this interval. The entire area was flooded during the earliest Eifelian, when the first vestiges of the Azel Matti Ridge become evident by stratigraphic condensation. The palaeogeographic differentiation is most apparent during the Givetian, when a shoal with reduced carbonate sedimentation was established on the Azel Matti Ridge passing towards the west and east into basinal environments of the Reggane and Ahnet basins, respectively. The Foum Belrem Ridge is distinguished by increased subsidence during the early Givetian and by revived uplift during the late Givetian. In the Mouydir Basin further east, up to 1000 m of shales were deposited during the Givetian. The early Frasnian is marked by the ubiquitous sedimentation of black shales and bituminous styliolinites. These lithologies occur repeatedly already during the Middle Devonian and document intermittent anoxic conditions. The basin and ridge topography is levelled by the shallowing-up sequence of up to 1400 m thick upper Frasnian and Famennian shales which grade into a deltaic sequence of uppermost Famennian/Tournaisian sandstones. The up to now only vaguely discriminated lithostratigraphic formations of the Devonian have been biostratigraphically defined in suitable type sections.
Solar Cells prepared with Spray-ILGAR Indium Sulfide buffer layers on Cu(In,Ga)Se2 Absorbers
- Nicholas A. Allsop, Christian A. Kaufmann, Axel Neisser, Marin Rusu, Andreas Hänsel, Martha C. Lux-Steiner, Christian H. Fischer
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- Journal:
- MRS Online Proceedings Library Archive / Volume 865 / 2005
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- 01 February 2011, F14.23
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- 2005
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Indium sulfide buffer layers deposited by the Spray-Ion Layer Gas Reaction (Spray-ILGAR) technique have recently been used with Cu(In,Ga)(S,Se)2 absorbers giving cells with an efficiency equal to the cadmium sulfide references. In this paper we show the first results from cells prepared with Cu(In,Ga)Se2 absorbers (sulfur free). These cells reach an efficiency of 13.1% which remains slightly below the efficiency of the cadmium sulfide reference. However, temperature dependant current-voltage measurements reveal that the activation energy of the dominant recombination mechanism remains unchanged from the cadmium sulfide buffered cells indicating that recombination remains within the space charge region.
High-Efficient ZnO/PVD-CdS/Cu(In,Ga)Se2 Thin Film Solar Cells: Formation of the Buffer-Absorber Interface and Transport Properties
- Marin Rusu, Thilo Glatzel, Christian A. Kaufmann, Axel Neisser, Susanne Siebentritt, Sascha Sadewasser, Thomas Schedel-Niedrig, Martha Ch. Lux-Steiner
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- Journal:
- MRS Online Proceedings Library Archive / Volume 865 / 2005
- Published online by Cambridge University Press:
- 01 February 2011, F14.25
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- 2005
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For preparation of ZnO/CdS/Cu(In,Ga)Se2 solar cells, physical vapor deposition (PVD) was employed to deposit CdS buffer layers in ultrahigh vacuum on Se-decapped absorber surfaces, thus realizing an all ‘dry' fabrication process of the device. An 14.1% total area and 14.5% active area efficient ZnO/CdS/Cu(In,Ga)Se2 solar cell under AM1.5 conditions was achieved after annealing the as-prepared solar cells in air. Kelvin probe force microscopy (KPFM) measurements were carried out in-situ to monitor the initial growth of the CdS buffer layer on the absorber, as well as its electronic properties, in particular, the work function. It was observed that the PVD-CdS growth is initially inhibited at the absorber grain boundaries. Quantum efficiency measurements allowed us to suppose that during the initial growth stage a passivation of the grain boundaries occurs. The latter explains the higher short-circuit currents of the cells with PVD-CdS compared to their references with CdS grown by chemical bath deposition (CBD). The beneficial effect of the annealing seems to originate from a formation of a region with higher band gap than that of the absorber bulk and inverted conductivity type at the absorber surface, close to the CdS/Cu(In,Ga)Se2 interface, leading to a dramatic change in the electronic transport properties and finally, to a significant enhancement of the open-circuit voltage. Annealing of the ZnO/PVD-CdS/Cu(In,Ga)Se2 solar cells provides formation of PVDCdS/ Cu(In,Ga)Se2 interface with properties similar to that of reference samples with CBD-CdS.
Design of a window layer for flexible Cu(In,Ga)Se2 thin film solar cell devices
- Christian A. Kaufmann, Axel Neisser, Reiner Klenk, Roland Scheer, Hans-Werner Schock
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- Journal:
- MRS Online Proceedings Library Archive / Volume 865 / 2005
- Published online by Cambridge University Press:
- 01 February 2011, F7.5
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- 2005
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For laboratory scale devices the transfer of the Cu(In,Ga)Se2 (CIGSe) thin film technology from a rigid float glass substrate to flexible titanium foil is achieved. Here we will highlight the effect of the rough, flexible substrate on the electrical and optical characteristics of the transparent window layers of such devices. The roughness of the substrate may give rise to changes in sheet resistance of the transparent front contact and in the reflectivity of the completed device. However, the devices deposited onto the kind of titanium foil substrate used in this work are smooth enough not to affect the sheet resistance; nevertheless optical effects are enough to affect the process window for an antireflective coating. With the use of an antireflective coating, a maximum efficiency of 17.4% could be reached for 0.5 cm2 area devices on glass.