10 results
The role of physical variables in biodiversity patterns of intertidal macroalgae along European coasts
- Araceli Puente, Xabier Guinda, Jose A. Juanes, Elvira Ramos, Beatriz Echavarri-Erasun, Camino F. De La Hoz, Steven Degraer, Francis Kerckhof, Natalia Bojanić, Maria Rousou, Helen Orav-Kotta, Jonne Kotta, Jérôme Jourde, Maria Luiza Pedrotti, Jean-Charles Leclerc, Nathalie Simon, Guy Bachelet, Nicolas Lavesque, Christos Arvanitidis, Christina Pavloudi, Sarah Faulwetter, Tasman P. Crowe, Jennifer Coughlan, Lisandro Benedetti Cecchi, Martina Dal Bello, Paolo Magni, Serena Como, Stefania Coppa, Giuseppe Andrea De Lucia, Tomas Rugins, Emilia Jankowska, Jan Marcin Weslawski, Jan Warzocha, Teresa Silva, Pedro Ribeiro, Valentina De Matos, Isabel Sousa-Pinto, Jesús Troncoso, Ohad Peleg, Gil Rilov, Free Espinosa, Angel Pérez Ruzafa, Matt Frost, Herman Hummel, Pim Van Avesaath
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- Journal:
- Journal of the Marine Biological Association of the United Kingdom / Volume 97 / Issue 3 / May 2017
- Published online by Cambridge University Press:
- 15 December 2016, pp. 549-560
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In the frame of the COST ACTION ‘EMBOS’ (Development and implementation of a pan-European Marine Biodiversity Observatory System), coverage of intertidal macroalgae was estimated at a range of marine stations along the European coastline (Subarctic, Baltic, Atlantic, Mediterranean). Based on these data, we tested whether patterns in macroalgal diversity and distribution along European intertidal rocky shores could be explained by a set of meteo-oceanographic variables. The variables considered were salinity, sea surface temperature, photosynthetically active radiation, significant wave height and tidal range and were compiled from three different sources: remote sensing, reanalysis technique and in situ measurement. These variables were parameterized to represent average conditions (mean values), variability (standard deviation) and extreme events (minimum and maximum values). The results obtained in this study contribute to reinforce the EMBOS network approach and highlight the necessity of considering meteo-oceanographic variables in long-term assessments. The broad spatial distribution of pilot sites has allowed identification of latitudinal and longitudinal gradients manifested through species composition, diversity and dominance structure of intertidal macroalgae. These patterns follow a latitudinal gradient mainly explained by sea surface temperature, but also by photosynthetically active radiation, salinity and tidal range. Additionally, a longitudinal gradient was also detected and could be linked to wave height.
Consistent patterns of spatial variability between NE Atlantic and Mediterranean rocky shores
- Martina Dal Bello, Jean-Charles Leclerc, Lisandro Benedetti-Cecchi, Giuseppe Andrea De Lucia, Christos Arvanitidis, Pim Van Avesaath, Guy Bachelet, Natalia Bojanic, Serena Como, Stefania Coppa, Jennifer Coughlan, Tasman Crowe, Steven Degraer, Free Espinosa, Sarah Faulwetter, Matt Frost, Xabier Guinda, Emilia Jankowska, Jérôme Jourde, Jose Antonio Juanes De La Pena, Francis Kerckhof, Jonne Kotta, Nicolas Lavesque, Paolo Magni, Valentina De Matos, Helen Orav-Kotta, Christina Pavloudi, Maria Luiza Pedrotti, Ohad Peleg, Angel Pérez-Ruzafa, Araceli Puente, Pedro Ribeiro, Fabienne Rigaut-Jalabert, Gil Rilov, Maria Rousou, Marcos Rubal, Tomas Ruginis, Teresa Silva, Nathalie Simon, Isabel Sousa-Pinto, Jesús Troncoso, Jan Warzocha, Jan Marcin Weslawski, Herman Hummel
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- Journal:
- Journal of the Marine Biological Association of the United Kingdom / Volume 97 / Issue 3 / May 2017
- Published online by Cambridge University Press:
- 11 November 2016, pp. 539-547
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Examining how variability in population abundance and distribution is allotted among different spatial scales can inform of processes that are likely to generate that variability. Results of studies dealing with scale issues in marine benthic communities suggest that variability is concentrated at small spatial scales (from tens of centimetres to few metres) and that spatial patterns of variation are consistent across ecosystems characterized by contrasting physical and biotic conditions, but this has not been formally tested. Here we quantified the variability in the distribution of intertidal rocky shore communities at a range of spatial scales, from tens of centimetres to thousands of kilometres, both in the NE Atlantic and the Mediterranean, and tested whether the observed patterns differed between the two basins. We focused on canopy-forming macroalgae and associated understorey assemblages in the low intertidal, and on the distribution of Patella limpets at mid intertidal levels. Our results highlight that patterns of spatial variation, at each scale investigated, were consistent between the Atlantic and the Mediterranean, suggesting that similar ecological processes operate in these regions. In contrast with former studies, variability in canopy cover, species richness and limpet abundance was equally distributed among spatial scales, possibly reflecting the fingerprint of multiple processes. Variability in community structure of low intertidal assemblages, instead, peaked at the largest scale, suggesting that oceanographic processes and climatic gradients may be important. We conclude that formal comparisons of variability across scales nested in contrasting systems are needed, before any generalization on patterns and processes can be made.
Essence of the patterns of cover and richness of intertidal hard bottom communities: a pan-European study
- Jonne Kotta, Helen Orav-Kotta, Holger Jänes, Herman Hummel, Christos Arvanitidis, Pim Van Avesaath, Guy Bachelet, Lisandro Benedetti-Cecchi, Natalia Bojanić, Serena Como, Stefania Coppa, Jennifer Coughlan, Tasman Crowe, Martina Dal Bello, Steven Degraer, Jose Antonio Juanes De La Pena, Valentina Kirienko Fernandes De Matos, Free Espinosa, Sarah Faulwetter, Matt Frost, Xabier Guinda, Emilia Jankowska, Jérôme Jourde, Francis Kerckhof, Nicolas Lavesque, Jean-Charles Leclerc, Paolo Magni, Christina Pavloudi, Maria Luiza Pedrotti, Ohad Peleg, Angel Pérez-Ruzafa, Araceli Puente, Pedro Ribeiro, Gil Rilov, Maria Rousou, Tomas Ruginis, Teresa Silva, Nathalie Simon, Isabel Sousa-Pinto, Jesús Troncoso, Jan Warzocha, Jan Marcin Weslawski
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- Journal:
- Journal of the Marine Biological Association of the United Kingdom / Volume 97 / Issue 3 / May 2017
- Published online by Cambridge University Press:
- 04 October 2016, pp. 525-538
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Coastal ecosystems are highly complex and driven by multiple environmental factors. To date we lack scientific evidence for the relative contribution of natural and anthropogenic drivers for the majority of marine habitats in order to adequately assess the role of different stressors across the European seas. Such relationship can be investigated by analysing the correlation between environmental variables and biotic patterns in multivariate space and taking into account non-linearities. Within the framework of the EMBOS (European Marine Biodiversity Observatory System) programme, hard bottom intertidal communities were sampled in a standardized way across European seas. Links between key natural and anthropogenic drivers and hard bottom communities were analysed using Boosted Regression Trees modelling. The study identified strong interregional variability and showed that patterns of hard bottom macroalgal and invertebrate communities were primarily a function of tidal regime, nutrient loading and water temperature (anomalies). The strength and shape of functional form relationships varied widely however among types of organisms (understorey algae composing mostly filamentous species, canopy-forming algae or sessile invertebrates) and aggregated community variables (cover or richness). Tidal regime significantly modulated the effect of nutrient load on the cover and richness of understorey algae and sessile invertebrates. In contrast, hydroclimate was more important for canopy algae and temperature anomalies and hydroclimate separately or interactively contributed to the observed patterns. The analyses also suggested that climate-induced shifts in weather patterns may result in the loss of algal richness and thereby in the loss of functional diversity in European hard bottom intertidal areas.
Geographic patterns of biodiversity in European coastal marine benthos
- Herman Hummel, Pim Van Avesaath, Sander Wijnhoven, Loran Kleine-Schaars, Steven Degraer, Francis Kerckhof, Natalia Bojanic, Sanda Skejic, Olja Vidjak, Maria Rousou, Helen Orav-Kotta, Jonne Kotta, Jérôme Jourde, Maria Luiza Pedrotti, Jean-Charles Leclerc, Nathalie Simon, Fabienne Rigaut-Jalabert, Guy Bachelet, Nicolas Lavesque, Christos Arvanitidis, Christina Pavloudi, Sarah Faulwetter, Tasman Crowe, Jennifer Coughlan, Lisandro Benedetti-Cecchi, Martina Dal Bello, Paolo Magni, Serena Como, Stefania Coppa, Anda Ikauniece, Tomas Ruginis, Emilia Jankowska, Jan Marcin Weslawski, Jan Warzocha, Sławomira Gromisz, Bartosz Witalis, Teresa Silva, Pedro Ribeiro, Valentina Kirienko Fernandes De Matos, Isabel Sousa-Pinto, Puri Veiga, Jesús Troncoso, Xabier Guinda, Jose Antonio Juanes De La Pena, Araceli Puente, Free Espinosa, Angel Pérez-Ruzafa, Matt Frost, Caroline Louise Mcneill, Ohad Peleg, Gil Rilov
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- Journal:
- Journal of the Marine Biological Association of the United Kingdom / Volume 97 / Issue 3 / May 2017
- Published online by Cambridge University Press:
- 14 September 2016, pp. 507-523
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Within the COST action EMBOS (European Marine Biodiversity Observatory System) the degree and variation of the diversity and densities of soft-bottom communities from the lower intertidal or the shallow subtidal was measured at 28 marine sites along the European coastline (Baltic, Atlantic, Mediterranean) using jointly agreed and harmonized protocols, tools and indicators. The hypothesis tested was that the diversity for all taxonomic groups would decrease with increasing latitude. The EMBOS system delivered accurate and comparable data on the diversity and densities of the soft sediment macrozoobenthic community over a large-scale gradient along the European coastline. In contrast to general biogeographic theory, species diversity showed no linear relationship with latitude, yet a bell-shaped relation was found. The diversity and densities of benthos were mostly positively correlated with environmental factors such as temperature, salinity, mud and organic matter content in sediment, or wave height, and related with location characteristics such as system type (lagoons, estuaries, open coast) or stratum (intertidal, subtidal). For some relationships, a maximum (e.g. temperature from 15–20°C; mud content of sediment around 40%) or bimodal curve (e.g. salinity) was found. In lagoons the densities were twice higher than in other locations, and at open coasts the diversity was much lower than in other locations. We conclude that latitudinal trends and regional differences in diversity and densities are strongly influenced by, i.e. merely the result of, particular sets and ranges of environmental factors and location characteristics specific to certain areas, such as the Baltic, with typical salinity clines (favouring insects) and the Mediterranean, with higher temperatures (favouring crustaceans). Therefore, eventual trends with latitude are primarily indirect and so can be overcome by local variation of environmental factors.
Improved early results with cavopulmonary connections
- Antonio R. Mott, Thomas L. Spray, J. William Gaynor, Rodolfo I. Godinez, Susan C. Nicolson, James M. Steven, William M. DeCampli, Gregory J. Schears, Gil Wernovsky
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- Journal:
- Cardiology in the Young / Volume 11 / Issue 1 / January 2001
- Published online by Cambridge University Press:
- 01 July 2011, pp. 3-11
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Background: We describe the recent results in a large cohort of patients with functionally single ventricle who underwent various modifications of cavopulmonary connections. Methods: Using the database at our institution, we identified all children who underwent cavopulmonary connection operations between June 1995 and June 1997. Demographic data, surgical history, and perioperative course were reviewed. Results: We performed 130 consecutive operations in 113 patients. The procedures included superior cavopulmonary connections in the form of the HemiFontan procedure in 45 instances, and bidirectional Glenn procedures in 11, and bilateral superior cavopulmonary connections in 7. The median age of these patients was 7.0 months. We completed Fontan operations using a fenestrated lateral tunnel on 47 occasions, and using an extracardiac conduit 9 times, 5 of which were fenestrated. A lateral tunnel without fenestration was constructed inone patient. The median age for these procedures was 19.5 months. In the remaining 10 instances, we revised Fontan procedures at a median age of 8 years. Diagnoses included hypoplastic left heart syndrome in 43 patients, double outlet right ventricle in 22, heterotaxy in 13, tricuspid atresia in 13, and a miscellaneous group accounting for the other 22. One death (0.7%) occurred within 30 days of surgery. Clinical seizures occurred in 7 children (5.3%), 6 had no residual neurologic deficits. Atrial pacing was needed in 14 children (10.7%) because of transient junctional rhythm, and 2 received treatment for supraventricular tachycardia. Pleural effusions were diagnosed radiographically after 31 of 130 (24%) procedures. Diuretic therapy resolved the effusion in 21 of these, with only 6 children requiring thoracostomy catheter drainage, and 4 undergoing thoracentesis alone. The median length of stay on the intensive care unit was 2 days, with a range from 1 to 30 days, and median stay in hospital was 6 days, with a range from 3 to 58 days. Conclusion: Mortality and perioperative morbidity after cavopulmonary connections have decreased dramatically in the current era. The long-term results of staged reconstruction for functionally single ventricle, nonetheless, await ongoing study.
Case 43 - Another day at the office …based anesthesia
- from Part 4 - Contributions from the University of Miami Miller School of Medicine under Michael C. Lewis
- Edited by Christopher J. Gallagher, State University of New York, Stony Brook, Michael C. Lewis, University of Miami School of Medicine, Deborah A. Schwengel
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- Book:
- Core Clinical Competencies in Anesthesiology
- Published online:
- 06 July 2010
- Print publication:
- 12 April 2010, pp 232-235
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Rogues' Gallery of Contributing Authors
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- By Ramon Abola, Rishimani Adsumelli, Syed Azim, Tazeen Beg, Helene Benveniste, Louis Chun, Ramtin Cohanim, Dominick Coleman, Joseph Conrad, Tommy Corrado, Jason Daras, Michelle DiGuglielmo, Vedan Djesevic, Andrew Drollinger, Kathleen Dubrow, Brian Durkin, Ralph Epstein, Christopher J. Gallagher, Xiaojun Guo, Sofie Hussain, Ron Jasiewicz, Anna Kogan, Ursula Landman, Rany Makaryus, Daryn Moller, Tate Montgomery, Matthew Neal, Khoa Nguyen, Marco Palmieri, Shaji Poovathor, Eric Posner, Deborah Richman, Andrew Rozbruch, Misako Sakamaki, Joy Schabel, Bharathi Scott, Peggy Seidman, Shiena Sharma, Vishal Sharma, Ellen Steinberg, Neera Tewari, Jane Yi, Jonida Zeqo, Peter Chung, John Denny, Steven H. Ginsberg, Jeremy Grayson, Jonathan Kraidin, Stephen Lemke, Tejal Patel, Salvatore Zisa, Charles Cowles, Marc Rozner, Shawn Banks, Deborah Brauer, Lebron Cooper, V. Samepathi David, Steve Gayer, Steven Gil, Eric A. Harris, Murlikrishna Kannan, Michael C. Lewis, David A. Lindley, Carlos M. Mijares, Sana Nini, Shafeena Nurani, Sujatha Pentakota, Edgar Pierre, Amy Klash Pulido, Michael Rossi, Miguel Santos, Nancy Setzer-Saade, Adam Sewell, Omair H. Toor, Ashish Udeshi, Patricia Wawroski, Lauren C. Berkow, Dan Berkowitz, Ramola Bhambhani, Kerry K. Blaha, Veronica Busso, Adam J. Carinci, Paul J. Christo, R. Blaine Easley, Ralph J. Fuchs, Samuel M. Galvagno, Nishant Gandhi, Andrew Goins, Robert S. Greenberg, Sayeh Hamzehzadeh, Theresa L. Hartsell, Eugenie Heitmiller, Jeremy M. Huff, Brijen L. Joshi, Sapna Kudchadkar, Jennifer K. Lee, Ira Lehrer, Peter Lin, Justin Lockman, Christine L. Mai, Christina Miller, Nanhi Mitter, Gillian Newman, Daniel Nyhan, Lale Odekon, Rabi Panigrahi, Melissa Pant, Alexander Papangelou, Mark Rossberg, Adam Schiavi, Steven J. Schwartz, Deborah A. Schwengel, Brandon M. Togioka, Tina Tran, Emmett Whitaker, Bradford D. Winters, Christopher Wu, Elena J. Holak, Paul S. Pagel
- Edited by Christopher J. Gallagher, State University of New York, Stony Brook, Michael C. Lewis, University of Miami School of Medicine, Deborah A. Schwengel
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- Book:
- Core Clinical Competencies in Anesthesiology
- Published online:
- 06 July 2010
- Print publication:
- 12 April 2010, pp xi-xii
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Nomenclature and databases for the surgical treatment of congenital cardiac disease – an updated primer and an analysis of opportunities for improvement
- Part of
- Jeffrey Phillip Jacobs, Marshall Lewis Jacobs, Constantine Mavroudis, Carl Lewis Backer, Francois G. Lacour-Gayet, Christo I. Tchervenkov, Rodney C. G. Franklin, Marie J. Béland, Kathy J. Jenkins, Hal Walters III, Emile A. Bacha, Bohdan Maruszewski, Hiromi Kurosawa, David Robinson Clarke, J. William Gaynor, Thomas L. Spray, Giovanni Stellin, Tjark Ebels, Otto N. Krogmann, Vera D. Aiello, Steven D. Colan, Paul Weinberg, Jorge M. Giroud, Allen Everett, Gil Wernovsky, Martin J. Elliott, Fred H. Edwards
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- Journal:
- Cardiology in the Young / Volume 18 / Issue S2 / December 2008
- Published online by Cambridge University Press:
- 01 December 2008, pp. 38-62
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This review discusses the historical aspects, current state of the art, and potential future advances in the areas of nomenclature and databases for the analysis of outcomes of treatments for patients with congenitally malformed hearts. We will consider the current state of analysis of outcomes, lay out some principles which might make it possible to achieve life-long monitoring and follow-up using our databases, and describe the next steps those involved in the care of these patients need to take in order to achieve these objectives. In order to perform meaningful multi-institutional analyses, we suggest that any database must incorporate the following six essential elements: use of a common language and nomenclature, use of an established uniform core dataset for collection of information, incorporation of a mechanism of evaluating case complexity, availability of a mechanism to assure and verify the completeness and accuracy of the data collected, collaboration between medical and surgical subspecialties, and standardised protocols for life-long follow-up.
During the 1990s, both The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons created databases to assess the outcomes of congenital cardiac surgery. Beginning in 1998, these two organizations collaborated to create the International Congenital Heart Surgery Nomenclature and Database Project. By 2000, a common nomenclature, along with a common core minimal dataset, were adopted by The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons, and published in the Annals of Thoracic Surgery. In 2000, The International Nomenclature Committee for Pediatric and Congenital Heart Disease was established. This committee eventually evolved into the International Society for Nomenclature of Paediatric and Congenital Heart Disease. The working component of this international nomenclature society has been The International Working Group for Mapping and Coding of Nomenclatures for Paediatric and Congenital Heart Disease, also known as the Nomenclature Working Group. By 2005, the Nomenclature Working Group crossmapped the nomenclature of the International Congenital Heart Surgery Nomenclature and Database Project of The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons with the European Paediatric Cardiac Code of the Association for European Paediatric Cardiology, and therefore created the International Paediatric and Congenital Cardiac Code, which is available for free download from the internet at [http://www.IPCCC.NET].
This common nomenclature, the International Paediatric and Congenital Cardiac Code, and the common minimum database data set created by the International Congenital Heart Surgery Nomenclature and Database Project, are now utilized by both The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons. Between 1998 and 2007 inclusive, this nomenclature and database was used by both of these two organizations to analyze outcomes of over 150,000 operations involving patients undergoing surgical treatment for congenital cardiac disease.
Two major multi-institutional efforts that have attempted to measure the complexity of congenital heart surgery are the Risk Adjustment in Congenital Heart Surgery-1 system, and the Aristotle Complexity Score. Current efforts to unify the Risk Adjustment in Congenital Heart Surgery-1 system and the Aristotle Complexity Score are in their early stages, but encouraging. Collaborative efforts involving The European Association for Cardio-Thoracic Surgery and The Society of Thoracic Surgeons are under way to develop mechanisms to verify the completeness and accuracy of the data in the databases. Under the leadership of The MultiSocietal Database Committee for Pediatric and Congenital Heart Disease, further collaborative efforts are ongoing between congenital and paediatric cardiac surgeons and other subspecialties, including paediatric cardiac anaesthesiologists, via The Congenital Cardiac Anesthesia Society, paediatric cardiac intensivists, via The Pediatric Cardiac Intensive Care Society, and paediatric cardiologists, via the Joint Council on Congenital Heart Disease and The Association for European Paediatric Cardiology.
In finalising our review, we emphasise that analysis of outcomes must move beyond mortality, and encompass longer term follow-up, including cardiac and non cardiac morbidities, and importantly, those morbidities impacting health related quality of life. Methodologies must be implemented in these databases to allow uniform, protocol driven, and meaningful, long term follow-up.
Contributors
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- By Isabella Aboderin, W. Andrew Achenbaum, Katherine R. Allen, Toni C. Antonucci, Sara Arber, Claudine Attias‐Donfut, Paul B. Baltes, Sandhi Maria Barreto, Vern L. Bengtson, Simon Biggs, Joanna Bornat, Julie B. Boron, Mike Boulton, Clive E. Bowman, Marjolein Broese van Groenou, Edna Brown, Robert N. Butler, Bill Bytheway, Neena L. Chappell, Neil Charness, Kaare Christensen, Peter G. Coleman, Ingrid Arnet Connidis, Neal E. Cutler, Sara J. Czaja, Svein Olav Daatland, Lia Susana Daichman, Adam Davey, Bleddyn Davies, Freya Dittmann‐Kohli, Glen H. Elder, Carroll L. Estes, Mike Featherstone, Amy Fiske, Alexandra Freund, Daphna Gans, Linda K. George, Roseann Giarrusso, Chris Gilleard, Jay Ginn, Edlira Gjonça, Elena L. Grigorenko, Jaber F. Gubrium, Sarah Harper, Jutta Heckhausen, Akiko Hashimoto, Jon Hendricks, Mike Hepworth, Charlotte Ikels, James S. Jackson, Yuri Jang, Bernard Jeune, Malcolm L. Johnson, Randi S. Jones, Alexandre Kalache, Robert L. Kane, Rosalie A. Kane, Ingrid Keller, Rose Anne Kenny, Thomas B. L. Kirkwood, Kees Knipscheer, Martin Kohli, Gisela Labouvie‐Vief, Kristina Larsson, Shu‐Chen Li, Charles F. Longino, Ariela Lowenstein, Erick McCarthy, Gerald E. McClearn, Brendan McCormack, Elizabeth MacKinlay, Alfons Marcoen, Michael Marmot, Tom Margrain, Victor W. Marshall, Elizabeth A. Maylor, Ruud ter Meulen, Harry R. Moody, Robert A. Neimeyer, Demi Patsios, Margaret J. Penning, Stephen A. Petrill, Chris Phillipson, Leonard W. Poon, Norella M. Putney, Jill Quadagno, Pat Rabbitt, Jennifer Reid Keene, Sandra G. Reynolds, Steven R. Sabat, Clive Seale, Merril Silverstein, Hannes B. Staehelin, Ursula M. Staudinger, Robert J. Sternberg, Debra Street, Philip Taylor, Fleur Thomése, Mats Thorslund, Jinzhou Tian, Theo van Tilburg, Fernando M. Torres‐Gil, Josy Ubachs‐Moust, Christina Victor, K. Warner Shaie, Anthony M. Warnes, James L. Werth, Sherry L. Willis, François‐Charles Wolff, Bob Woods
- Edited by Malcolm L. Johnson, University of Bristol
- Edited in association with Vern L. Bengtson, University of Southern California, Peter G. Coleman, University of Southampton, Thomas B. L. Kirkwood, University of Newcastle upon Tyne
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- Book:
- The Cambridge Handbook of Age and Ageing
- Published online:
- 05 June 2016
- Print publication:
- 01 December 2005, pp xii-xvi
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Microstructure and Recording Noise of Thin Film Longitudinal Media
- Tadashi Yogi, Thao A. Nguyena, Steven E. Lambert, Grace L. Gorman, Gil Castillo
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- MRS Online Proceedings Library Archive / Volume 232 / 1991
- Published online by Cambridge University Press:
- 15 February 2011, 3
- Print publication:
- 1991
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The magnetic and recording characteristics of Co-based thin film media are strongly influenced by microstructure. The media microstructural characteristics, in turn, depend on sputtering conditions of underlayers and magnetic layers. The role of Cr underlayer thickness and sputtering pressure have been reported previously. The present work examines the growth morphology and recording properties of a CoPtCr alloy on Cr underlayers where the deposition conditions such as sputtering pressure and rf bias were independently varied for the Cr underlayer and the magnetic layer. We find that the growth morphology of the magnetic layer is governed primarily by the deposition condition of the Cr underlayer. In particular, increased sputtering pressure for the Cr underlayer produces columnar morphology which induces isolation of the grains in the magnetic layer. This results in a significant reduction in the recording noise due to reduced intergrain exchange coupling. On the other hand, the application of ff bias during the deposition of the magnetic layer promotes more continuous magnetic grains, thereby increasing the recording noise. The observed trends in microstructure and recording noise can be understood qualitatively in terms of Thornton's microstructure diagram and the competition between micromorphological roughness and adatom mobility during the film growth.