29 results
361 WDR5 represents a therapeutically exploitable target for cancer stem cells in glioblastoma
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- Christopher Hubert, Kelly Mitchell, Samuel Sprowls, Sajina Shakya, Sonali Arora, Daniel J. Silver, Christopher M. Goins, Lisa Wallace, Gustavo Roversi, Rachel Schafer, Kristen Kay, Tyler E. Miller, Adam Lauko, John Bassett, Anjali Kashyap, J. D’Amato Kass, Erin E. Mulkearns-Hubert, Sadie Johnson, Joseph Alvarado, Jeremy N. Rich, Patrick J. Paddison, Anoop P. Patel, Shaun R. Stauffer, Christopher G. Hubert, Justin D. Lathia
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- Journal:
- Journal of Clinical and Translational Science / Volume 7 / Issue s1 / April 2023
- Published online by Cambridge University Press:
- 24 April 2023, p. 107
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OBJECTIVES/GOALS: Glioblastomas (GBMs) are heterogeneous, treatment-resistant tumors that are driven by populations of cancer stem cells (CSCs). In this study, we perform an epigenetic-focused functional genomics screen in GBM organoids and identify WDR5 as an essential epigenetic regulator in the SOX2-enriched, therapy resistant cancer stem cell niche. METHODS/STUDY POPULATION: Despite their importance for tumor growth, few molecular mechanisms critical for CSC population maintenance have been exploited for therapeutic development. We developed a spatially resolved loss-of-function screen in GBM patient-derived organoids to identify essential epigenetic regulators in the SOX2-enriched, therapy resistant niche. Our niche-specific screens identified WDR5, an H3K4 histone methyltransferase responsible for activating specific gene expression, as indispensable for GBM CSC growth and survival. RESULTS/ANTICIPATED RESULTS: In GBM CSC models, WDR5 inhibitors blocked WRAD complex assembly and reduced H3K4 trimethylation and expression of genes involved in CSC-relevant oncogenic pathways. H3K4me3 peaks lost with WDR5 inhibitor treatment occurred disproportionally on POU transcription factor motifs, required for stem cell maintenance and including the POU5F1(OCT4)::SOX2 motif. We incorporated a SOX2/OCT4 motif driven GFP reporter system into our CSC cell models and found that WDR5 inhibitor treatment resulted in dose-dependent silencing of stem cell reporter activity. Further, WDR5 inhibitor treatment altered the stem cell state, disrupting CSC in vitro growth and self-renewal as well as in vivo tumor growth. DISCUSSION/SIGNIFICANCE: Our results unveiled the role of WDR5 in maintaining the CSC state in GBM and provide a rationale for therapeutic development of WDR5 inhibitors for GBM and other advanced cancers. This conceptual and experimental framework can be applied to many cancers, and can unmask unique microenvironmental biology and rationally designed combination therapies.
Practice Variation between Salaried and Fee-for-Service Surgeons for Lumbar Surgery
- Daniel Banaszek, Greg McIntosh, Raphaële Charest-Morin, Edward Abraham, Neil Manson, Michael G. Johnson, Christopher S. Bailey, Y Raja Rampersaud, R Andrew Glennie, Jerome Paquet, Andrew Nataraj, Michael H. Weber, Sean Christie, Najmedden Attabib, Alex Soroceanu, Adrienne Kelly, Hamilton Hall, Ken Thomas, Charles Fisher, Nicolas Dea
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- Journal:
- Canadian Journal of Neurological Sciences / Volume 50 / Issue 4 / July 2023
- Published online by Cambridge University Press:
- 16 June 2022, pp. 604-611
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Objective:
To examine differences in surgical practices between salaried and fee-for-service (FFS) surgeons for two common degenerative spine conditions. Surgeons may offer different treatments for similar conditions on the basis of their compensation mechanism.
Methods:The study assessed the practices of 63 spine surgeons across eight Canadian provinces (39 FFS surgeons and 24 salaried) who performed surgery for two lumbar conditions: stable spinal stenosis and degenerative spondylolisthesis. The study included a multicenter, ambispective review of consecutive spine surgery patients enrolled in the Canadian Spine Outcomes and Research Network registry between October 2012 and July 2018. The primary outcome was the difference in type of procedures performed between the two groups. Secondary study variables included surgical characteristics, baseline patient factors, and patient-reported outcome.
Results:For stable spinal stenosis (n = 2234), salaried surgeons performed statistically fewer uninstrumented fusion (p < 0.05) than FFS surgeons. For degenerative spondylolisthesis (n = 1292), salaried surgeons performed significantly more instrumentation plus interbody fusions (p < 0.05). There were no statistical differences in patient-reported outcomes between the two groups.
Conclusions:Surgeon compensation was associated with different approaches to stable lumbar spinal stenosis and degenerative lumbar spondylolisthesis. Salaried surgeons chose a more conservative approach to spinal stenosis and a more aggressive approach to degenerative spondylolisthesis, which highlights that remuneration is likely a minor determinant in the differences in practice of spinal surgery in Canada. Further research is needed to further elucidate which variables, other than patient demographics and financial incentives, influence surgical decision-making.
Effect of Metarhizium anisopliae (Clavicipitaceae) on Rhagoletis mendax (Diptera: Tephritidae) pupae and adults
- Justin M. Renkema, G. Christopher Cutler, Jason M. Sproule, Dan L. Johnson
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- The Canadian Entomologist / Volume 152 / Issue 2 / April 2020
- Published online by Cambridge University Press:
- 15 January 2020, pp. 237-248
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Blueberry maggot (Rhagoletis mendax Curran (Diptera: Tephritidae)) is a pest of blueberries (Vaccinium Linnaeus (Ericaceae)). Tephritid flies, including Rhagoletis Loew species, are susceptible to entomopathogenic fungi, but mortality levels depend on life stage targeted. We tested Metarhizium anisopliae (Metschnikoff) (Clavicipitaceae) strain S54 by application to pupae in the laboratory and using soil drenches in the laboratory and field. We hypothesised that younger (pre-diapause) pupae would be more susceptible to infection than older (post-diapause) pupae. In the laboratory, R. mendax emergence was reduced from 80% in the control to 57–60% with M. anisopliae. Rhagoletis mendax longevity was reduced by two days for both application timings, and mycosed cadavers increased by 9% and 27% with applications to younger and older pupae, respectively, compared to controls. In the field, R. mendax emergence was reduced by 50% with application to younger pupae compared to controls and applications to older pupae. The surfactant Silwet L77 caused reduced R. mendax emergence when pupae were dipped in suspensions. Even though M. anisopliae S54 did not greatly reduce emergence or longevity, infection was successful and younger pupae may be more susceptible than older pupae. Research with other M. anisopliae isolates against multiple life stages should be conducted and effects of soil variables on pathogenicity determined.
Phenology of Five Palmer amaranth (Amaranthus palmeri) Populations Grown in Northern Indiana and Arkansas
- Douglas J. Spaunhorst, Pratap Devkota, William G. Johnson, Reid J. Smeda, Christopher J. Meyer, Jason K. Norsworthy
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- Journal:
- Weed Science / Volume 66 / Issue 4 / July 2018
- Published online by Cambridge University Press:
- 27 March 2018, pp. 457-469
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Palmer amaranth (Amaranthus palmeri S. Watson) is a problematic weed encountered in U.S. cotton (Gossypium hirsutum L.) and soybean [Glycine max (L.) Merr.] production, with infestations spreading northward. This research investigated the influence of planting date (early, mid-, and late season) and population (AR, IN, MO, MS, NE, and TN) on A. palmeri growth and reproduction at two locations. All populations planted early or midseason at Throckmorton Purdue Agricultural Center (TPAC) and Arkansas Agriculture Research and Extension Center (AAREC) measured 196 and 141 cm or more, respectively. Amaranthus palmeri height did not exceed 168 and 134 cm when planted late season at TPAC and AAREC, respectively. Early season planted A. palmeri from NE grew to 50% of maximum height 8 to 13 d earlier than all other populations under TPAC conditions. In addition, the NE population planted early, mid-, and late season achieved 50% inflorescence emergence 5, 4, and 6 d earlier than all other populations, respectively. All populations established at TPAC produced fewer than 100,000 seeds plant−1. No population planted at TPAC and AAREC produced more than 740 and 1,520 g plant−1 of biomass at 17 and 19 wk after planting, respectively. Planting date influenced the distribution of male and female plants at TPAC, but not at AAREC. Amaranthus palmeri from IN and MS planted late season had male-to-female plant ratios of 1.3:1 and 1.7:1, respectively. Amaranthus palmeri introduced to TPAC from NE can produce up to 7,500 seeds plant−1 if emergence occurs in mid-July. An NE A. palmeri population exhibited biological characteristics allowing it to be highly competitive if introduced to TPAC due to a similar latitudinal range, but was least competitive when introduced to AAREC. Although A. palmeri originating from different locations can vary biologically, plants exhibited environmental plasticity and could complete their life cycle and contribute to spreading populations.
Herbicide Program Approaches for Managing Glyphosate-Resistant Palmer Amaranth (Amaranthus palmeri) and Waterhemp (Amaranthus tuberculatus and Amaranthus rudis) in Future Soybean-Trait Technologies
- Christopher J. Meyer, Jason K. Norsworthy, Bryan G. Young, Lawrence E. Steckel, Kevin W. Bradley, William G. Johnson, Mark M. Loux, Vince M. Davis, Greg R. Kruger, Mohammad T. Bararpour, Joseph T. Ikley, Douglas J. Spaunhorst, Thomas R. Butts
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- Weed Technology / Volume 29 / Issue 4 / December 2015
- Published online by Cambridge University Press:
- 20 January 2017, pp. 716-729
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Herbicide-resistant Amaranthus spp. continue to cause management difficulties in soybean. New soybean technologies under development, including resistance to various combinations of glyphosate, glufosinate, dicamba, 2,4-D, isoxaflutole, and mesotrione, will make possible the use of additional herbicide sites of action in soybean than is currently available. When this research was conducted, these soybean traits were still regulated and testing herbicide programs with the appropriate soybean genetics in a single experiment was not feasible. Therefore, the effectiveness of various herbicide programs (PRE herbicides followed by POST herbicides) was evaluated in bare-ground experiments on glyphosate-resistant Palmer amaranth and glyphosate-resistant waterhemp (both tall and common) at locations in Arkansas, Illinois, Indiana, Missouri, Nebraska, and Tennessee. Twenty-five herbicide programs were evaluated; 5 of which were PRE herbicides only, 10 were PRE herbicides followed by POST herbicides 3 to 4 wks after (WA) the PRE application (EPOST), and 10 were PRE herbicides followed by POST herbicides 6 to 7 WA the PRE application (LPOST). Programs with EPOST herbicides provided 94% or greater control of Palmer amaranth and waterhemp at 3 to 4 WA the EPOST. Overall, programs with LPOST herbicides resulted in a period of weed emergence in which weeds would typically compete with a crop. Weeds were not completely controlled with the LPOST herbicides because weed sizes were larger (≥ 15 cm) compared with their sizes at the EPOST application (≤ 7 cm). Most programs with LPOST herbicides provided 80 to 95% control at 3 to 4 WA applied LPOST. Based on an orthogonal contrast, using a synthetic-auxin herbicide LPOST improves control of Palmer amaranth and waterhemp over programs not containing a synthetic-auxin LPOST. These results show herbicides that can be used in soybean and that contain auxinic- or HPPD-resistant traits will provide growers with an opportunity for better control of glyphosate-resistant Palmer amaranth and waterhemp over a wide range of geographies and environments.
Evolution of Resistance to Auxinic Herbicides: Historical Perspectives, Mechanisms of Resistance, and Implications for Broadleaf Weed Management in Agronomic Crops
- J. Mithila, J. Christopher Hall, William G. Johnson, Kevin B. Kelley, Dean E. Riechers
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- Weed Science / Volume 59 / Issue 4 / December 2011
- Published online by Cambridge University Press:
- 20 January 2017, pp. 445-457
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Auxinic herbicides are widely used for control of broadleaf weeds in cereal crops and turfgrass. These herbicides are structurally similar to the natural plant hormone auxin, and induce several of the same physiological and biochemical responses at low concentrations. After several decades of research to understand the auxin signal transduction pathway, the receptors for auxin binding and resultant biochemical and physiological responses have recently been discovered in plants. However, the precise mode of action for the auxinic herbicides is not completely understood despite their extensive use in agriculture for over six decades. Auxinic herbicide-resistant weed biotypes offer excellent model species for uncovering the mode of action as well as resistance to these compounds. Compared with other herbicide families, the incidence of resistance to auxinic herbicides is relatively low, with only 29 auxinic herbicide-resistant weed species discovered to date. The relatively low incidence of resistance to auxinic herbicides has been attributed to the presence of rare alleles imparting resistance in natural weed populations, the potential for fitness penalties due to mutations conferring resistance in weeds, and the complex mode of action of auxinic herbicides in sensitive dicot plants. This review discusses recent advances in the auxin signal transduction pathway and its relation to auxinic herbicide mode of action. Furthermore, comprehensive information about the genetics and inheritance of auxinic herbicide resistance and case studies examining mechanisms of resistance in auxinic herbicide-resistant broadleaf weed biotypes are provided. Within the context of recent findings pertaining to auxin biology and mechanisms of resistance to auxinic herbicides, agronomic implications of the evolution of resistance to these herbicides are discussed in light of new auxinic herbicide-resistant crops that will be commercialized in the near future.
Certified Crop Advisors’ Perceptions of Giant Ragweed (Ambrosia trifida) Distribution, Herbicide Resistance, and Management in the Corn Belt
- Emilie E. Regnier, S. Kent Harrison, Mark M. Loux, Christopher Holloman, Ramarao Venkatesh, Florian Diekmann, Robin Taylor, Robert A. Ford, David E. Stoltenberg, Robert G. Hartzler, Adam S. Davis, Brian J. Schutte, John Cardina, Kris J. Mahoney, William G. Johnson
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- Journal:
- Weed Science / Volume 64 / Issue 2 / June 2016
- Published online by Cambridge University Press:
- 20 January 2017, pp. 361-377
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Giant ragweed has been increasing as a major weed of row crops in the last 30 yr, but quantitative data regarding its pattern and mechanisms of spread in crop fields are lacking. To address this gap, we conducted a Web-based survey of certified crop advisors in the U.S. Corn Belt and Ontario, Canada. Participants were asked questions regarding giant ragweed and crop production practices for the county of their choice. Responses were mapped and correlation analyses were conducted among the responses to determine factors associated with giant ragweed populations. Respondents rated giant ragweed as the most or one of the most difficult weeds to manage in 45% of 421 U.S. counties responding, and 57% of responding counties reported giant ragweed populations with herbicide resistance to acetolactate synthase inhibitors, glyphosate, or both herbicides. Results suggest that giant ragweed is increasing in crop fields outward from the east-central U.S. Corn Belt in most directions. Crop production practices associated with giant ragweed populations included minimum tillage, continuous soybean, and multiple-application herbicide programs; ecological factors included giant ragweed presence in noncrop edge habitats, early and prolonged emergence, and presence of the seed-burying common earthworm in crop fields. Managing giant ragweed in noncrop areas could reduce giant ragweed migration from noncrop habitats into crop fields and slow its spread. Where giant ragweed is already established in crop fields, including a more diverse combination of crop species, tillage practices, and herbicide sites of action will be critical to reduce populations, disrupt emergence patterns, and select against herbicide-resistant giant ragweed genotypes. Incorporation of a cereal grain into the crop rotation may help suppress early giant ragweed emergence and provide chemical or mechanical control options for late-emerging giant ragweed.
Early-Season Palmer Amaranth and Waterhemp Control from Preemergence Programs Utilizing 4-Hydroxyphenylpyruvate Dioxygenase–Inhibiting and Auxinic Herbicides in Soybean
- Christopher J. Meyer, Jason K. Norsworthy, Bryan G. Young, Lawrence E. Steckel, Kevin W. Bradley, William G. Johnson, Mark M. Loux, Vince M. Davis, Greg R. Kruger, Mohammad T. Bararpour, Joseph T. Ikley, Douglas J. Spaunhorst, Thomas R. Butts
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- Journal:
- Weed Technology / Volume 30 / Issue 1 / March 2016
- Published online by Cambridge University Press:
- 20 January 2017, pp. 67-75
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Palmer amaranth and waterhemp have become increasingly troublesome weeds throughout the United States. Both species are highly adaptable and emerge continuously throughout the summer months, presenting the need for a residual PRE application in soybean. To improve season-long control of Amaranthus spp., 19 PRE treatments were evaluated on glyphosate-resistant Palmer amaranth in 2013 and 2014 at locations in Arkansas, Indiana, Nebraska, Illinois, and Tennessee; and on glyphosate-resistant waterhemp at locations in Illinois, Missouri, and Nebraska. The two Amaranthus species were analyzed separately; data for each species were pooled across site-years, and site-year was included as a random variable in the analyses. The dissipation of weed control throughout the course of the experiments was compared among treatments with the use of regression analysis where percent weed control was described as a function of time (the number of weeks after treatment [WAT]). At the mean (i.e., average) WAT (4.3 and 3.2 WAT for Palmer amaranth and waterhemp, respectively) isoxaflutole + S-metolachlor + metribuzin had the highest predicted control of Palmer amaranth (98%) and waterhemp (99%). Isoxaflutole + S-metolachlor + metribuzin, S-metolachlor + mesotrione, and flumioxazin + pyroxasulfone had a predicted control ≥ 97% and similar model parameter estimates, indicating control declined at similar rates for these treatments. Dicamba and 2,4-D provided some, short-lived residual control of Amaranthus spp. When dicamba was added to metribuzin or S-metolachlor, control increased compared to dicamba alone. Flumioxazin + pyroxasulfone, a currently labeled PRE, performed similarly to treatments containing isoxaflutole or mesotrione. Additional sites of action will provide soybean growers more opportunities to control these weeds and reduce the potential for herbicide resistance.
Contributors
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- By Mitchell Aboulafia, Frederick Adams, Marilyn McCord Adams, Robert M. Adams, Laird Addis, James W. Allard, David Allison, William P. Alston, Karl Ameriks, C. Anthony Anderson, David Leech Anderson, Lanier Anderson, Roger Ariew, David Armstrong, Denis G. Arnold, E. J. Ashworth, Margaret Atherton, Robin Attfield, Bruce Aune, Edward Wilson Averill, Jody Azzouni, Kent Bach, Andrew Bailey, Lynne Rudder Baker, Thomas R. Baldwin, Jon Barwise, George Bealer, William Bechtel, Lawrence C. Becker, Mark A. Bedau, Ernst Behler, José A. Benardete, Ermanno Bencivenga, Jan Berg, Michael Bergmann, Robert L. Bernasconi, Sven Bernecker, Bernard Berofsky, Rod Bertolet, Charles J. Beyer, Christian Beyer, Joseph Bien, Joseph Bien, Peg Birmingham, Ivan Boh, James Bohman, Daniel Bonevac, Laurence BonJour, William J. Bouwsma, Raymond D. Bradley, Myles Brand, Richard B. Brandt, Michael E. Bratman, Stephen E. Braude, Daniel Breazeale, Angela Breitenbach, Jason Bridges, David O. Brink, Gordon G. Brittan, Justin Broackes, Dan W. Brock, Aaron Bronfman, Jeffrey E. Brower, Bartosz Brozek, Anthony Brueckner, Jeffrey Bub, Lara Buchak, Otavio Bueno, Ann E. Bumpus, Robert W. Burch, John Burgess, Arthur W. Burks, Panayot Butchvarov, Robert E. Butts, Marina Bykova, Patrick Byrne, David Carr, Noël Carroll, Edward S. Casey, Victor Caston, Victor Caston, Albert Casullo, Robert L. Causey, Alan K. L. Chan, Ruth Chang, Deen K. Chatterjee, Andrew Chignell, Roderick M. Chisholm, Kelly J. Clark, E. J. Coffman, Robin Collins, Brian P. Copenhaver, John Corcoran, John Cottingham, Roger Crisp, Frederick J. Crosson, Antonio S. Cua, Phillip D. Cummins, Martin Curd, Adam Cureton, Andrew Cutrofello, Stephen Darwall, Paul Sheldon Davies, Wayne A. Davis, Timothy Joseph Day, Claudio de Almeida, Mario De Caro, Mario De Caro, John Deigh, C. F. Delaney, Daniel C. Dennett, Michael R. DePaul, Michael Detlefsen, Daniel Trent Devereux, Philip E. Devine, John M. Dillon, Martin C. Dillon, Robert DiSalle, Mary Domski, Alan Donagan, Paul Draper, Fred Dretske, Mircea Dumitru, Wilhelm Dupré, Gerald Dworkin, John Earman, Ellery Eells, Catherine Z. Elgin, Berent Enç, Ronald P. Endicott, Edward Erwin, John Etchemendy, C. Stephen Evans, Susan L. Feagin, Solomon Feferman, Richard Feldman, Arthur Fine, Maurice A. Finocchiaro, William FitzPatrick, Richard E. Flathman, Gvozden Flego, Richard Foley, Graeme Forbes, Rainer Forst, Malcolm R. Forster, Daniel Fouke, Patrick Francken, Samuel Freeman, Elizabeth Fricker, Miranda Fricker, Michael Friedman, Michael Fuerstein, Richard A. Fumerton, Alan Gabbey, Pieranna Garavaso, Daniel Garber, Jorge L. A. Garcia, Robert K. Garcia, Don Garrett, Philip Gasper, Gerald Gaus, Berys Gaut, Bernard Gert, Roger F. Gibson, Cody Gilmore, Carl Ginet, Alan H. Goldman, Alvin I. Goldman, Alfonso Gömez-Lobo, Lenn E. Goodman, Robert M. Gordon, Stefan Gosepath, Jorge J. E. Gracia, Daniel W. Graham, George A. Graham, Peter J. Graham, Richard E. Grandy, I. Grattan-Guinness, John Greco, Philip T. Grier, Nicholas Griffin, Nicholas Griffin, David A. Griffiths, Paul J. Griffiths, Stephen R. Grimm, Charles L. Griswold, Charles B. Guignon, Pete A. Y. Gunter, Dimitri Gutas, Gary Gutting, Paul Guyer, Kwame Gyekye, Oscar A. Haac, Raul Hakli, Raul Hakli, Michael Hallett, Edward C. Halper, Jean Hampton, R. James Hankinson, K. R. Hanley, Russell Hardin, Robert M. Harnish, William Harper, David Harrah, Kevin Hart, Ali Hasan, William Hasker, John Haugeland, Roger Hausheer, William Heald, Peter Heath, Richard Heck, John F. Heil, Vincent F. Hendricks, Stephen Hetherington, Francis Heylighen, Kathleen Marie Higgins, Risto Hilpinen, Harold T. Hodes, Joshua Hoffman, Alan Holland, Robert L. Holmes, Richard Holton, Brad W. Hooker, Terence E. Horgan, Tamara Horowitz, Paul Horwich, Vittorio Hösle, Paul Hoβfeld, Daniel Howard-Snyder, Frances Howard-Snyder, Anne Hudson, Deal W. Hudson, Carl A. Huffman, David L. Hull, Patricia Huntington, Thomas Hurka, Paul Hurley, Rosalind Hursthouse, Guillermo Hurtado, Ronald E. Hustwit, Sarah Hutton, Jonathan Jenkins Ichikawa, Harry A. Ide, David Ingram, Philip J. Ivanhoe, Alfred L. Ivry, Frank Jackson, Dale Jacquette, Joseph Jedwab, Richard Jeffrey, David Alan Johnson, Edward Johnson, Mark D. Jordan, Richard Joyce, Hwa Yol Jung, Robert Hillary Kane, Tomis Kapitan, Jacquelyn Ann K. Kegley, James A. Keller, Ralph Kennedy, Sergei Khoruzhii, Jaegwon Kim, Yersu Kim, Nathan L. King, Patricia Kitcher, Peter D. Klein, E. D. Klemke, Virginia Klenk, George L. Kline, Christian Klotz, Simo Knuuttila, Joseph J. Kockelmans, Konstantin Kolenda, Sebastian Tomasz Kołodziejczyk, Isaac Kramnick, Richard Kraut, Fred Kroon, Manfred Kuehn, Steven T. Kuhn, Henry E. Kyburg, John Lachs, Jennifer Lackey, Stephen E. Lahey, Andrea Lavazza, Thomas H. Leahey, Joo Heung Lee, Keith Lehrer, Dorothy Leland, Noah M. Lemos, Ernest LePore, Sarah-Jane Leslie, Isaac Levi, Andrew Levine, Alan E. Lewis, Daniel E. Little, Shu-hsien Liu, Shu-hsien Liu, Alan K. L. Chan, Brian Loar, Lawrence B. Lombard, John Longeway, Dominic McIver Lopes, Michael J. Loux, E. J. Lowe, Steven Luper, Eugene C. Luschei, William G. Lycan, David Lyons, David Macarthur, Danielle Macbeth, Scott MacDonald, Jacob L. Mackey, Louis H. Mackey, Penelope Mackie, Edward H. Madden, Penelope Maddy, G. B. Madison, Bernd Magnus, Pekka Mäkelä, Rudolf A. Makkreel, David Manley, William E. Mann (W.E.M.), Vladimir Marchenkov, Peter Markie, Jean-Pierre Marquis, Ausonio Marras, Mike W. Martin, A. P. Martinich, William L. McBride, David McCabe, Storrs McCall, Hugh J. McCann, Robert N. McCauley, John J. McDermott, Sarah McGrath, Ralph McInerny, Daniel J. McKaughan, Thomas McKay, Michael McKinsey, Brian P. McLaughlin, Ernan McMullin, Anthonie Meijers, Jack W. Meiland, William Jason Melanson, Alfred R. Mele, Joseph R. Mendola, Christopher Menzel, Michael J. Meyer, Christian B. Miller, David W. Miller, Peter Millican, Robert N. Minor, Phillip Mitsis, James A. Montmarquet, Michael S. Moore, Tim Moore, Benjamin Morison, Donald R. Morrison, Stephen J. Morse, Paul K. Moser, Alexander P. D. Mourelatos, Ian Mueller, James Bernard Murphy, Mark C. Murphy, Steven Nadler, Jan Narveson, Alan Nelson, Jerome Neu, Samuel Newlands, Kai Nielsen, Ilkka Niiniluoto, Carlos G. Noreña, Calvin G. Normore, David Fate Norton, Nikolaj Nottelmann, Donald Nute, David S. Oderberg, Steve Odin, Michael O’Rourke, Willard G. Oxtoby, Heinz Paetzold, George S. Pappas, Anthony J. Parel, Lydia Patton, R. P. Peerenboom, Francis Jeffry Pelletier, Adriaan T. Peperzak, Derk Pereboom, Jaroslav Peregrin, Glen Pettigrove, Philip Pettit, Edmund L. Pincoffs, Andrew Pinsent, Robert B. Pippin, Alvin Plantinga, Louis P. Pojman, Richard H. Popkin, John F. Post, Carl J. Posy, William J. Prior, Richard Purtill, Michael Quante, Philip L. Quinn, Philip L. Quinn, Elizabeth S. Radcliffe, Diana Raffman, Gerard Raulet, Stephen L. Read, Andrews Reath, Andrew Reisner, Nicholas Rescher, Henry S. Richardson, Robert C. Richardson, Thomas Ricketts, Wayne D. Riggs, Mark Roberts, Robert C. Roberts, Luke Robinson, Alexander Rosenberg, Gary Rosenkranz, Bernice Glatzer Rosenthal, Adina L. Roskies, William L. Rowe, T. M. Rudavsky, Michael Ruse, Bruce Russell, Lilly-Marlene Russow, Dan Ryder, R. M. Sainsbury, Joseph Salerno, Nathan Salmon, Wesley C. Salmon, Constantine Sandis, David H. Sanford, Marco Santambrogio, David Sapire, Ruth A. Saunders, Geoffrey Sayre-McCord, Charles Sayward, James P. Scanlan, Richard Schacht, Tamar Schapiro, Frederick F. Schmitt, Jerome B. Schneewind, Calvin O. Schrag, Alan D. Schrift, George F. Schumm, Jean-Loup Seban, David N. Sedley, Kenneth Seeskin, Krister Segerberg, Charlene Haddock Seigfried, Dennis M. Senchuk, James F. Sennett, William Lad Sessions, Stewart Shapiro, Tommie Shelby, Donald W. Sherburne, Christopher Shields, Roger A. Shiner, Sydney Shoemaker, Robert K. Shope, Kwong-loi Shun, Wilfried Sieg, A. John Simmons, Robert L. Simon, Marcus G. Singer, Georgette Sinkler, Walter Sinnott-Armstrong, Matti T. Sintonen, Lawrence Sklar, Brian Skyrms, Robert C. Sleigh, Michael Anthony Slote, Hans Sluga, Barry Smith, Michael Smith, Robin Smith, Robert Sokolowski, Robert C. Solomon, Marta Soniewicka, Philip Soper, Ernest Sosa, Nicholas Southwood, Paul Vincent Spade, T. L. S. Sprigge, Eric O. Springsted, George J. Stack, Rebecca Stangl, Jason Stanley, Florian Steinberger, Sören Stenlund, Christopher Stephens, James P. Sterba, Josef Stern, Matthias Steup, M. A. Stewart, Leopold Stubenberg, Edith Dudley Sulla, Frederick Suppe, Jere Paul Surber, David George Sussman, Sigrún Svavarsdóttir, Zeno G. Swijtink, Richard Swinburne, Charles C. Taliaferro, Robert B. Talisse, John Tasioulas, Paul Teller, Larry S. Temkin, Mark Textor, H. S. Thayer, Peter Thielke, Alan Thomas, Amie L. Thomasson, Katherine Thomson-Jones, Joshua C. Thurow, Vzalerie Tiberius, Terrence N. Tice, Paul Tidman, Mark C. Timmons, William Tolhurst, James E. Tomberlin, Rosemarie Tong, Lawrence Torcello, Kelly Trogdon, J. D. Trout, Robert E. Tully, Raimo Tuomela, John Turri, Martin M. Tweedale, Thomas Uebel, Jennifer Uleman, James Van Cleve, Harry van der Linden, Peter van Inwagen, Bryan W. Van Norden, René van Woudenberg, Donald Phillip Verene, Samantha Vice, Thomas Vinci, Donald Wayne Viney, Barbara Von Eckardt, Peter B. M. Vranas, Steven J. Wagner, William J. Wainwright, Paul E. Walker, Robert E. Wall, Craig Walton, Douglas Walton, Eric Watkins, Richard A. Watson, Michael V. Wedin, Rudolph H. Weingartner, Paul Weirich, Paul J. Weithman, Carl Wellman, Howard Wettstein, Samuel C. Wheeler, Stephen A. White, Jennifer Whiting, Edward R. Wierenga, Michael Williams, Fred Wilson, W. Kent Wilson, Kenneth P. Winkler, John F. Wippel, Jan Woleński, Allan B. Wolter, Nicholas P. Wolterstorff, Rega Wood, W. Jay Wood, Paul Woodruff, Alison Wylie, Gideon Yaffe, Takashi Yagisawa, Yutaka Yamamoto, Keith E. Yandell, Xiaomei Yang, Dean Zimmerman, Günter Zoller, Catherine Zuckert, Michael Zuckert, Jack A. Zupko (J.A.Z.)
- Edited by Robert Audi, University of Notre Dame, Indiana
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- The Cambridge Dictionary of Philosophy
- Published online:
- 05 August 2015
- Print publication:
- 27 April 2015, pp ix-xxx
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Modelling intrusions through quiescent and moving ambients
- Christopher G. Johnson, Andrew J. Hogg, Herbert E. Huppert, R. Stephen J. Sparks, Jeremy C. Phillips, Anja C. Slim, Mark J. Woodhouse
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- Journal of Fluid Mechanics / Volume 771 / 25 May 2015
- Published online by Cambridge University Press:
- 20 April 2015, pp. 370-406
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Volcanic eruptions commonly produce buoyant ash-laden plumes that rise through the stratified atmosphere. On reaching their level of neutral buoyancy, these plumes cease rising and transition to horizontally spreading intrusions. Such intrusions occur widely in density-stratified fluid environments, and in this paper we develop a shallow-layer model that governs their motion. We couple this dynamical model to a model for particle transport and sedimentation, to predict both the time-dependent distribution of ash within volcanic intrusions and the flux of ash that falls towards the ground. In an otherwise quiescent atmosphere, the intrusions spread axisymmetrically. We find that the buoyancy-inertial scalings previously identified for continuously supplied axisymmetric intrusions are not realised by solutions of the governing equations. By calculating asymptotic solutions to our model we show that the flow is not self-similar, but is instead time-dependent only in a narrow region at the front of the intrusion. This non-self-similar behaviour results in the radius of the intrusion growing with time
$t$ as
$t^{3/4}$, rather than
$t^{2/3}$ as suggested previously. We also identify a transition to drag-dominated flow, which is described by a similarity solution with radial growth now proportional to
$t^{5/9}$. In the presence of an ambient wind, intrusions are not axisymmetric. Instead, they are predominantly advected downstream, while at the same time spreading laterally and thinning vertically due to persistent buoyancy forces. We show that close to the source, this lateral spreading is in a buoyancy-inertial regime, whereas far downwind, the horizontal buoyancy forces that drive the spreading are balanced by drag. Our results emphasise the important role of buoyancy-driven spreading, even at large distances from the source, in the formation of the flowing thin horizontally extensive layers of ash that form in the atmosphere as a result of volcanic eruptions.
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- By Cecil S. Ash, Paul Barach, Ulrike Buehner, M. Ross Bullock, Leonardo Canale, Henry G. Chou, Jeffrey A. Claridge, John J. Como, Armagan Dagal, Martin Dauber, James S. Davis, Shalini Dhir, François Donati, Roman Dudaryk, Richard P. Dutton, Talmage D. Egan, Yashar Eshraghi, John R. Fisgus, Jeff Gadsden, Sugantha Ganapathy, Mark A. Gerhardt, Inderjit Gill, Joseph F. Golob, Glenn P. Gravlee, Marcello Guglielmi, Jana Hambley, Peter Hebbard, Elena J. Holak, Khadil Hosein, Ken Johnson, Matthew A. Joy, George W. Kanellakos, Olga Kaslow, Arthur M. Lam, Vanetta Levesque, Jessica Anne Lovich-Sapola, M. Jocelyn Loy, Peter F. Mahoney, Donn Marciniak, Maureen McCunn, Craig C. McFarland, Maroun J. Mhanna, Timothy Moore, Cynthia Nguyen, Maxim Novikov, E. Orestes O’Brien, Ketan P. Parekh, Claire L. Park, Michael J. A. Parr, Elie Rizkala, Steven Roth, Alistair Royse, Colin Royse, Kasia Petelenz Rubin, David Ryan, Claire Sandstrom, Carl I. Schulman, Rishad Shaikh, Ranjita Sharma, Jeffrey H. Silverstein, Peter Slinger, Charles E. Smith, Christopher Smith, Paul Soeding, Rakesh V. Sondekoppam, P. David Soran, Eldar Søreide, Elizabeth A. Steele, Kristian Strand, Dennis M. Super, Kutaiba Tabbaa, Nicholas T. Tarmey, Joshua M. Tobin, Kalpana Tyagaraj, Heather A. Vallier, Sandra Werner, Earl Willis Weyers, William C. Wilson, Shoji Yokobori, Charles J. Yowler
- Edited by Charles E. Smith
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- Book:
- Trauma Anesthesia
- Published online:
- 05 April 2015
- Print publication:
- 09 April 2015, pp vii-x
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Will Changing Demographics Affect U.S. Cheese Demand?
- Christopher G. Davis, Donald Blayney, Diansheng Dong, Steven T. Yen, Rachel J. Johnson
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- Journal:
- Journal of Agricultural and Applied Economics / Volume 43 / Issue 2 / May 2011
- Published online by Cambridge University Press:
- 26 January 2015, pp. 259-273
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U.S. cheese consumption has grown considerably over the last three decades. Using a censored demand model and Nielsen Homescan retail data, this study identifies price and non-price factors affecting the demand for differentiated cheese products. Own-price and expenditure elasticities for all of the cheese products are statistically significant and elastic. Results also reveal that a strong substitution relationship exists among all cheese products. Although demographic influences are generally smaller than those related to prices and expenditures, empirical findings show that household size, college educated female heads of household who are age 40 and older, residing in the South, Central, and Western regions of the United States, as well as Black heads of household, have positive statistically significant effects on consumers' cheese purchases.
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- By Neal Aaron, Yuemi An-Grogan, Brian Bausano, Michael Cassara, Becky Damazo, Michael Falk, Jeremy Samuel Faust, Aaron Gingrich, Brandon J. Godbout, Steven A. Godwin, Scott Goldberg, Kelvin Harold, Jessica Hernandez, Lisa Jacobson, Jennifer Johnson, Nikita K. Joshi, Marianne Juarez, Jared M. Kutzin, Kristin McKee, Jacqueline A. Nemer, Jeanne A. Noble, Yasuharu Okuda, Viril Patel, Kevin Reed, Nicholas Renz, David Salzman, Christopher Sampson, Andrew Schmidt, Kirill Shishlov, Michael Smith, Christopher G. Strother, Julian Villar, Jason Wagner, Ernest Wang, Scott D. Weingart
- Edited by Lisa Jacobson, Yasuharu Okuda, Steven A. Godwin
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- Book:
- SimWars Simulation Case Book: Emergency Medicine
- Published online:
- 05 February 2015
- Print publication:
- 15 January 2015, pp ix-x
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- By Venkataraman Anantharaman, Philip D. Anderson, Christopher W. Baugh, J. Stephen Bohan, Kirsten Boyd, Matthias Brachmann, Peter R. Brown, Shelley Calder, David Callaway, Peter Cameron, Jody Crane, Meaghan Cussen, Christina Dempsey, Jonathan A. Edlow, Thomas Fleischmann, Robert L. Freitas, John D. Halamka, Manuel Hernandez, Cherri Hobgood, Jock Hoffman, Steven Horng, Kirk B. Jensen, Jennifer R. Johnson, Stephanie Kayden, Tasnim Khan, Daniel G. Kirkpatrick, James Lennon, Mary Leupold, Thom Mayer, J. Lawrence Mottley, Scott B. Murray, Deirdre Mylod, Larry A. Nathanson, Michael P. Pietrzak, Elke Platz, Nadeem Qureshi, Matthew M. Rice, Andrew Schenkel, Chet Schrader, Puneet Seth, Richard B. Siegrist, David Smith, Robert E. Suter, Carrie Tibbles, Sebastian N. Walker, Lee A. Wallis, Julie Welch, Leana S. Wen
- Edited by Stephanie Kayden, Philip D. Anderson, Robert Freitas, Elke Platz
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- Book:
- Emergency Department Leadership and Management
- Published online:
- 05 December 2014
- Print publication:
- 27 November 2014, pp ix-xii
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Contributors
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- By Tod C. Aeby, Melanie D. Altizer, Ronan A. Bakker, Meghann E. Batten, Anita K. Blanchard, Brian Bond, Megan A. Brady, Saweda A. Bright, Ellen L. Brock, Amy Brown, Ashley Carroll, Jori S. Carter, Frances Casey, Weldon Chafe, David Chelmow, Jessica M. Ciaburri, Stephen A. Cohen, Adrianne M. Colton, PonJola Coney, Jennifer A. Cross, Julie Zemaitis DeCesare, Layson L. Denney, Megan L. Evans, Nicole S. Fanning, Tanaz R. Ferzandi, Katie P. Friday, Nancy D. Gaba, Rajiv B. Gala, Andrew Galffy, Adrienne L. Gentry, Edward J. Gill, Philippe Girerd, Meredith Gray, Amy Hempel, Audra Jolyn Hill, Chris J. Hong, Kathryn A. Houston, Patricia S. Huguelet, Warner K. Huh, Jordan Hylton, Christine R. Isaacs, Alison F. Jacoby, Isaiah M. Johnson, Nicole W. Karjane, Emily E. Landers, Susan M. Lanni, Eduardo Lara-Torre, Lee A. Learman, Nikola Alexander Letham, Rachel K. Love, Richard Scott Lucidi, Elisabeth McGaw, Kimberly Woods McMorrow, Christopher A. Manipula, Kirk J. Matthews, Michelle Meglin, Megan Metcalf, Sarah H. Milton, Gaby Moawad, Christopher Morosky, Lindsay H. Morrell, Elizabeth L. Munter, Erin L. Murata, Amanda B. Murchison, Nguyet A. Nguyen, Nan G. O’Connell, Tony Ogburn, K. Nathan Parthasarathy, Thomas C. Peng, Ashley Peterson, Sarah Peterson, John G. Pierce, Amber Price, Heidi J. Purcell, Ronald M. Ramus, Nicole Calloway Rankins, Fidelma B. Rigby, Amanda H. Ritter, Barbara L. Robinson, Danielle Roncari, Lisa Rubinsak, Jennifer Salcedo, Mary T. Sale, Peter F. Schnatz, John W. Seeds, Kathryn Shaia, Karen Shelton, Megan M. Shine, Haller J. Smith, Roger P. Smith, Nancy A. Sokkary, Reni A. Soon, Aparna Sridhar, Lilja Stefansson, Laurie S. Swaim, Chemen M. Tate, Hong-Thao Thieu, Meredith S. Thomas, L. Chesney Thompson, Tiffany Tonismae, Angela M. Tran, Breanna Walker, Alan G. Waxman, C. Nathan Webb, Valerie L. Williams, Sarah B. Wilson, Elizabeth M. Yoselevsky, Amy E. Young
- Edited by David Chelmow, Virginia Commonwealth University, Christine R. Isaacs, Virginia Commonwealth University, Ashley Carroll, Virginia Commonwealth University
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- Book:
- Acute Care and Emergency Gynecology
- Published online:
- 05 November 2014
- Print publication:
- 30 October 2014, pp ix-xiv
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- By Ra‘anan Boustan, Jonathan P. Conant, Brian Croke, Susanna Elm, Hugh Elton, Geoffrey Greatrex, Peter J. Heather, Kenneth G. Holum, Caroline Humfress, Scott F. Johnson, Christopher Kelly, Étienne De La Vaissière, Noel Lenski, Michael Maas, Maya Maskarinec, Andy Merrills, Richard Payne, Walter Pohl, Michele Renee Salzman, Joseph E. Sanzo, Peter Sarris, Raymond Van Dam, Edward Watts, Susan Wessel
- Edited by Michael Maas, Rice University, Houston
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- Book:
- The Cambridge Companion to the Age of Attila
- Published online:
- 05 October 2014
- Print publication:
- 29 September 2014, pp xiii-xiv
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- By Ainsworth Shaaron, Ayres Paul, Azevedo Roger, Bediou Benoit, Britt Anne, Kirsten R. Butcher, Chen Fei, Michelene T. H. Chi, Richard E. Clark, Ruth Colvin Clark, Sharon J. Derry, David F. Feldon, Fiorella Logan, J. D. Fletcher, Arthur C. Graesser, Hegarty Mary, HU Xiangen, Allison J. Jaeger, Janssen Jeroen, Cheryl I. Johnson, Ton De Jong, Kalyuga Slava, Kester Liesbeth, Kirschner Femke, Paul A. Kirschner, Susanne P. Lajoie, Ard W. Lazonder, Leutner Detlev, Low Renae, Richard K. Lowe, Richard E. Mayer, Benjamin D. Nye, Paas Fred, Pilegard Celeste, Jan L. Plass, Heather A. Priest, Renkl Alexander, Rouet Jean-FranÇois, Christopher A. Sanchez, Scheiter Katharina, Schmeck Annett, Schnotz Wolfgang, Ruth N. Schwartz, Bruce L. Sherin, Miriam Gamoran Sherin, Sweller John, Tobias Sigmund, Tamara Van Gog, Jeroen J. G. Van MerriËNboer, Jennifer Wiley, Alexander P. Wind, Ruth Wylie
- Edited by Richard E. Mayer, University of California, Santa Barbara
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- Book:
- The Cambridge Handbook of Multimedia Learning
- Published online:
- 05 August 2014
- Print publication:
- 28 July 2014, pp ix-x
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Bivalve Mollusk Assemblage of Bed III, Olduvai Gorge, Tanzania
- Claudia C. Johnson, Jackson K. Njau, Christopher E. Kauffman, Erle G. Kauffman, Nicholas P. Toth, Kathy Schick, John Kearney
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- Journal:
- The Paleontological Society Special Publications / Volume 13 / 2014
- Published online by Cambridge University Press:
- 26 July 2017, pp. 35-36
- Print publication:
- 2014
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Entraining gravity currents
- Christopher G. Johnson, Andrew J. Hogg
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- Journal:
- Journal of Fluid Mechanics / Volume 731 / 25 September 2013
- Published online by Cambridge University Press:
- 19 August 2013, pp. 477-508
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Entrainment of ambient fluid into a gravity current, while often negligible in laboratory-scale flows, may become increasingly significant in large-scale natural flows. We present a theoretical study of the effect of this entrainment by augmenting a shallow water model for gravity currents under a deep ambient with a simple empirical model for entrainment, based on experimental measurements of the fluid entrainment rate as a function of the bulk Richardson number. By analysing long-time similarity solutions of the model, we find that the decrease in entrainment coefficient at large Richardson number, due to the suppression of turbulent mixing by stable stratification, qualitatively affects the structure and growth rate of the solutions, compared to currents in which the entrainment is taken to be constant or negligible. In particular, mixing is most significant close to the front of the currents, leading to flows that are more dilute, deeper and slower than their non-entraining counterparts. The long-time solution of an inviscid entraining gravity current generated by a lock-release of dense fluid is a similarity solution of the second kind, in which the current grows as a power of time that is dependent on the form of the entrainment law. With an entrainment law that fits the experimental measurements well, the length of currents in this entraining inviscid regime grows with time approximately as
${t}^{0. 447} $. For currents instigated by a constant buoyancy flux, a different solution structure exists in which the current length grows as
${t}^{4/ 5} $. In both cases, entrainment is most significant close to the current front.
Contributors
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- By Lassi Alvesalo, Alberto Anta, Juan Luis Arsuaga, Shara E. Bailey, Priscilla Bayle, José María Bermúdez de Castro, Tracy K. Betsinger, Luca Bondioli, Scott E. Burnett, Concepcion de la Rúa, William N. Duncan, Ryan M. Durner, Heather J.H. Edgar, Scott M. Fitzpatrick, Michael R. Fong, Ana Gracia-Téllez, Theresa M. Grieco, Debbie Guatelli-Steinberg, Tsunehiko Hanihara, Brian E. Hemphill, Leslea J. Hlusko, Michael W. Holmes, Jean-Jacques Hublin, Toby E. Hughes, John P. Hunter, Joel D. Irish, Kent M. Johnson, Sri Kuswandari, Christine Lee, John R. Lukacs, Roberto Macchiarelli, Laura Martín-Francés, Ignacio Martínez, María Martinón-Torres, Arnaud Mazurier, Yuji Mizoguchi, Stephanie Moormann, Greg C. Nelson, Stephen D. Ousley, Oliver T. Rizk, G. Richard Scott, Roman Schomberg, Kes Schroer, Christopher M. Stojanowski, Grant C. Townsend, Christy G. Turner, Theresia C. Weston, Bernard Wood, Clément Zanolli, Linhu Zhang
- Edited by G. Richard Scott, University of Alaska, Fairbanks, Joel D. Irish, Liverpool John Moores University
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- Book:
- Anthropological Perspectives on Tooth Morphology
- Published online:
- 05 March 2013
- Print publication:
- 21 February 2013, pp viii-xi
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