11 results
Prediction of extubation failure in the paediatric cardiac ICU using machine learning and high-frequency physiologic data
- Sydney R. Rooney, Evan L. Reynolds, Mousumi Banerjee, Sara K. Pasquali, John R. Charpie, Michael G. Gaies, Gabe E. Owens
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- Journal:
- Cardiology in the Young / Volume 32 / Issue 10 / October 2022
- Published online by Cambridge University Press:
- 20 December 2021, pp. 1649-1656
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Background:
Cardiac intensivists frequently assess patient readiness to wean off mechanical ventilation with an extubation readiness trial despite it being no more effective than clinician judgement alone. We evaluated the utility of high-frequency physiologic data and machine learning for improving the prediction of extubation failure in children with cardiovascular disease.
Methods:This was a retrospective analysis of clinical registry data and streamed physiologic extubation readiness trial data from one paediatric cardiac ICU (12/2016-3/2018). We analysed patients’ final extubation readiness trial. Machine learning methods (classification and regression tree, Boosting, Random Forest) were performed using clinical/demographic data, physiologic data, and both datasets. Extubation failure was defined as reintubation within 48 hrs. Classifier performance was assessed on prediction accuracy and area under the receiver operating characteristic curve.
Results:Of 178 episodes, 11.2% (N = 20) failed extubation. Using clinical/demographic data, our machine learning methods identified variables such as age, weight, height, and ventilation duration as being important in predicting extubation failure. Best classifier performance with this data was Boosting (prediction accuracy: 0.88; area under the receiver operating characteristic curve: 0.74). Using physiologic data, our machine learning methods found oxygen saturation extremes and descriptors of dynamic compliance, central venous pressure, and heart/respiratory rate to be of importance. The best classifier in this setting was Random Forest (prediction accuracy: 0.89; area under the receiver operating characteristic curve: 0.75). Combining both datasets produced classifiers highlighting the importance of physiologic variables in determining extubation failure, though predictive performance was not improved.
Conclusion:Physiologic variables not routinely scrutinised during extubation readiness trials were identified as potential extubation failure predictors. Larger analyses are necessary to investigate whether these markers can improve clinical decision-making.
An evaluation of two perennial ryegrass cultivars (AberDart and Fennema) for sheep production in the uplands
- J. G. EVANS, M. D. FRASER, I. OWEN, D. A. DAVIES
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- Journal:
- The Journal of Agricultural Science / Volume 149 / Issue 2 / April 2011
- Published online by Cambridge University Press:
- 08 December 2010, pp. 235-248
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Under lowland conditions there is evidence to indicate that animals consuming ryegrasses bred for elevated water-soluble carbohydrate (WSC) concentrations are able to utilize the protein in their diet more efficiently, resulting in increased live-weight gain, milk production and lower loss of N. The current study evaluated the effects on upland sheep production of grazing two cultivars of perennial ryegrass nominally differing in WSC content. Replicate plots (n=4) of a cultivar bred for elevated levels of WSC (AberDart) and a control cultivar (Fennema) were grazed by ewes and lambs (pre-weaning) and by lambs only (post-weaning). Target surface sward heights of 40 and 60–70 mm were maintained during the pre-weaning and post-weaning periods, respectively. No differences were found in the WSC concentration of the two swards during either the pre-weaning or post-weaning periods. However, cultivar AberDart had a significantly lower fibre concentration during both periods (P<0·05), and a higher digestibility of organic matter in dry matter (DOMD) value during the post-weaning period (P<0·05). There was no cultivar effect of treatment on lamb growth during the pre-weaning period, but lamb live-weight gain was significantly higher for those grazing AberDart than Fennema during the post-weaning period (200 g/d v. 125 g/d; s.e.d.=26·5 g/d; P<0·01), leading to a greater proportion of lambs selected for slaughter by the end of September (0·99 v. 0·70 respectively; s.e.d.=0·062; P<0·05). The improved performance for lambs grazing AberDart relative to those grazing Fennema indicates that advances in plant breeding have the potential to improve the efficiency and profitability of lamb production in the uplands. However, additional research is required to explore the extent to which growing conditions in marginal environments influence the expression of traits.
Contributors
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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. 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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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- The Cambridge Dictionary of Christianity
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- 05 August 2012
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- 20 September 2010, pp xi-xliv
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11 - Imaging Cell Trafficking and Immune Cell Activation Using PET Reporter Genes
- Sanjiv Sam Gambhir, Stanford University School of Medicine, California, Shahriar S. Yaghoubi, Stanford University School of Medicine, California
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- Molecular Imaging with Reporter Genes
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- 07 September 2010
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- 31 May 2010, pp 258-274
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Summary
MAJOR IMMUNE CELL TYPES AND THEIR FUNCTIONS
Pathogen invasion of an immunocompetent host induces a coordinated response from a network of diverse immune cell types. The interactions between these various immune cell types are spatially and temporally regulated to facilitate the acquisition of effector mechanisms that ensure pathogen clearance. This section briefly summarizes the major components of the immune network and their actions during an immune response. A more detailed description of the development and function of specific immune cell types can be found in.
The immune network has two major components: the innate and adaptive immune systems. Cells of the innate immune system such as macrophages and dendritic cells generally make first contact with pathogens. Pathogen-derived molecules activate specific receptors on innate immune cells leading to the release of chemo-attractant molecules and recruitment of other inflammatory cells such as neutrophils. Furthermore, macrophages and dendritic cells ingest foreign proteins (or antigens) and migrate to nearby lymph nodes where they serve as antigen-presenting cells (APCs) in the initiation of the adaptive immune response.
T and B lymphocytes are the key cell types of the adaptive immune system. Both B and T cells express dedicated and highly variable cell surface receptors for antigen. Exposure to antigen together with help from T cells activates B cells to proliferate and differentiate into plasma cells that secrete antigen-specific antibodies that, by various effector mechanisms participate in antigen clearance. Once the invading pathogen has been cleared, the expanded antigen-specific B cell population contracts through apoptosis.
The Seasonal Incidence of Ixodes ricinus (L.) on Cattle in mid-Wales
- G. Owen Evans
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- Journal:
- Bulletin of Entomological Research / Volume 41 / Issue 3 / February 1951
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- 10 July 2009, pp. 459-468
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An investigation of the seasonal incidence of I. ricinus on cattle in N.W. Cardigani shire showed that there are normally two peaks of activity, one occurring in spring and the other in autumn. The infestation curve varied considerably from farm to farm according to the husbandry methods practised. Delayed stocking of infested pastures caused an initial higher infestation of the cattle but, except on one farm, did not prolong the infestation beyond the normal period of tick activity. A lower infestation in spring than in autumn occurred on two farms. This resulted from either the lighter stocking of the infested grazings in spring than in autumn or the partial exhaustion of unfed tick population by sheep grazing with the cattle during the spring only.
There was no evidence for the occurrence of a unimodal curve of tick activity in the region studied.
The Distribution of Ixodes ricinus (L.) on the Body of Cattle and Sheep
- G. Owen Evans
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- Journal:
- Bulletin of Entomological Research / Volume 41 / Issue 4 / May 1951
- Published online by Cambridge University Press:
- 10 July 2009, pp. 709-723
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Female ticks are almost entirely confined to head, axillary and inguinal regions of cattle. Larval and nymphal stages attach on the head and below the hock joints on the fore- and hind-legs.
The percentage of females on the forequarters of cattle increases during the course of the season, whether in spring or autumn; during the early stages of a season's activity the hindquarters carry a greater number than the forequarters. Later in the season the position is reversed. Suggestions are put forward to account for this phenomenon.
The head, axillary and inguinal regions are the major attachment sites of the female tick on sheep. In ewes the head region carries the higher percentage, but on lambs the axillary region is the most heavily infested. This difference may be due, to some extent, to the fleece of the ewes forming a barrier to the movement of unfed ticks towards the axillary and inguinal regions.
Lambs carry a heavier infestation between the 21st April and 6th June than ewes on the same grazing. This phenomenon has been discussed in the light of previous work in Northern England.
There is no reliable method of estimating the total infestation on cattle. A good picture of the seasonal incidence of the female tick on the host can be obtained from the hindquarters count. The standard count (the forebody) on sheep may be used for estimating total infestations.
On a new predatory Mite of economic Importance
- G. Owen Evans
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- Bulletin of Entomological Research / Volume 43 / Issue 2 / July 1952
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- 10 July 2009, pp. 397-401
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The biology and systematics of the predatory mites of the family Laelaptidae have received increased attention since they have been shown to be of importance in the control of phytophagous mites, especially Tetranychidae, resistant to modern insecticides. The predatory mites of economic importance are almost entirely confined to the sub–family Phytoseiinae Berl., 1910.
The Distribution and economic Importance of Ixodes ricinus (L.) in Wales and the Welsh Border Counties with special Reference to N.W. Cardiganshire
- G. Owen Evans
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- Bulletin of Entomological Research / Volume 41 / Issue 3 / February 1951
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- 10 July 2009, pp. 469-485
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Ixodes ricinus is the common tick infesting farmstock in Wales. Dermacentor reticulatus is recorded on cattle and sheep on two farms in N. Cardiganshire.
I. ricinus is widely distributed in the four major grassland zones of N.W. Cardiganshire. The most extensive areas of tick infestation are found on the marginal and hill farms. In lowland areas, except on extensive stretches of marshland, infested pastures are confined to isolated tracts of badly managed or poorly drained land. Infested grazings are invariably “rough” and contain one of the following plants as dominant: Festuca spp., Agrostis spp., Molinia caerulea, Nardus stricta, Pteris aquilina or Juncus spp. The degree of infestation of cattle depends on the relative area of the available grazing land colonised by the tick. Continuous stocking of infested pastures results in heavy infestations and vice versa.
Bovine piroplasmosis is the major tick-borne disease in N.W. Cardiganshire and predominates in the lowland districts. Outbreaks of the disease on marginal and hill farms are generally infrequent. Reasons are suggested for this phenomenon. Tick pyaemia is confined to lambs on hill grazings. The incidence of this disease is low.
The distribution of the tick in Wales and the border counties of Hereford and Salop shows a general relationship to areas of rough grazing. The tick is widespread in the western counties and is almost absent in the border counties. Radnorshire and Breconshire are interesting in that they have few infested farms in relation to the extensive nature of the “rough” grazing. A survey has also been conducted of the incidence of bovine piroplasmosis in Wales.
Studies on the Bionomics of the Sheep Ked, Melophagus ovinus, L., in West Wales
- G. Owen Evans
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- Journal:
- Bulletin of Entomological Research / Volume 40 / Issue 4 / February 1950
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- 10 July 2009, pp. 459-478
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A method is described for studying the life-cycle of Melophagus ovinus. The female ked matures in 6 to 7 days and the male in 10 to 11 days. Copulation takes place 16 hours after emergence and the first pupa is deposited by the female about 13 days after its emergence. The second and successive pupae are deposited at intervals of seven to eight days. The pupal stage covers 20 to 26 days (an average of 22·5 days for 28 observations). The life-cycle is completed in 33–36 days. Experimental conditions did not affect the duration of the various stages observed in the life-cycle.
An investigation of the periodic fluctuations in the infestation of a flock of Welsh sheep showed that the degree of infestation is influenced by the transference of keds between the sheep. Before lambing, keds are transferred from hoggs to two- to three-year old ewes and, after lambing, from ewes to lambs. The peak infestation of ewes and hoggs occurs before lambing. The maximum infestation of lambs occurs before shearing. At shearing the majority of adult keds and pupae are removed with the fleece. Adults surviving after shearing are killed at dipping. Depending on the nature of the dip, re-infestation results from pupae hatching in fleece or by the transference of keds from infested sheep coming into contact with the dipped flock. Keds disappear from the fleece through being devoured by the sheep, by the activity of insectivorous birds and through natural death. The transference of keds between sheep is achieved through contact and occurs readily when the ked is on the surface of the fleece. The vertical migration of the insect in the fleece is controlled by temperature and is not influenced by light.
The distribution of pupal and adult stages of M. ovinus in the fleece of lambs, hoggs and ewes is given. The position of attachment to the pupae is controlled by the depth of the fleece, deposition occurring on the wool fibres at a point where the temperature is suitable for their development. The age of the sheep influences the distribution of the ked, young sheep being more susceptible than older animals. In a flock, the higher infestation of hoggs compared to older ewes may be due to the higher initial infestation of the hoggs after dipping. Open fleeced sheep are more susceptible to ked infestation than tight fleeced sheep.
A review of the Laelaptid paraphages of the Myriapoda with descriptions of three new species (Acarina: Laelaptidae)
- G. Owen Evans
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- Journal:
- Parasitology / Volume 45 / Issue 3-4 / November 1955
- Published online by Cambridge University Press:
- 06 April 2009, pp. 352-368
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1. A review is given of the Laelaptid paraphages of the Myriapoda with a key to the genera.
2. One new genus, Scolopendracarus (type: S. brevipilis) and a new subgenus, Parajacobsonia (type: Jacobsonia tertia Vitzthum) of the genus Jacobsonia Berl. are proposed.
3. The following three species are described as new to science: Jacobsonia (Jacobsonia) audyi, Scolopendracarus brevipilis, Hypoaspis (Hypoaspis) polydesmoides.
4. The phylogeny and classification of the family Laelaptidae Berl. are discussed. A key is given to the subfamilies of the Laelaptidae.
Taxonomic Concepts in the Ascidae, with a Modified Setal Nomenclature for the Idiosoma of the Gamasina (Acarina: Mesostigmata)
- Evert E. Lindquist, G. Owen Evans
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- Journal:
- The Memoirs of the Entomological Society of Canada / Volume 97 / Issue S47 / 1965
- Published online by Cambridge University Press:
- 31 May 2012, pp. 5-66
- Print publication:
- 1965
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Generic and familial concepts of the Ascidae Voigts and Oudemans (= Blattisociidae Garman, Aceosejidae Baker and Wharton) are reviewed and modified from a world standpoint. The postembryonic developments of chaetotactic and external morphological features of the body and appendages are discussed. Twenty-two genera in three subfamilies are recognized, keyed, and defined: Arctoseius Thor, Iphidozercon Berlese, Xenoseius nov., and Zerconopsis Hull in the Arctoseiinae Evans; Cheiroseius Berlese and Platyseius Berlese in the Platyseiinae Evans; Aceodromus Muma, Antennoseius Berlese, Arctoseiodes Willmann, Asca Heyden, Blattisocius Keegan, Diseius nov., Gamasellodes Athias-Henriot, Hoploseius Berlese, Lasioseius Berlese, Leioseius Berlese, Melichares Hering, Neojordensia Evans, Proctolaelaps Berlese, Protogamasellus Karg, Rhinoseius Baker and Yunker, and Zercoseius Berlese in the Ascinae Voigts and Oudemans.Newly synonymized genera are Hyattella Krantz under Lasioseius, Mucroseius Lindquist and Orolaelaps DeLeon under Melichares, Garmaniella Westerboer under Proctolaelaps, and Tropicoseius Baker and Yunker under Rhinoseius. Genera removed from the Ascidae include Africoseius Krantz, Digamasellus Berlese, Laelaptoseius Womersley, and Zygoseius Berlese.
Modified systems of nomenclature based on holotrichous Gamasina are introduced and applied to setae on the dorsum of the idiosoma and on the venter of the opisthosoma.