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3,628 results on '"Gray, Andrew"'

106. Effects of antecedent hydrologic conditions, time dependence, and climate cycles on the suspended sediment load of the Salinas River, California

Author

Gray, Andrew B, Pasternack, Gregory B, Watson, Elizabeth B, Warrick, Jonathan A, and Goñi, Miguel A

Subjects
Suspended sediment, Non-stationary Effective discharge, El Nifio Southern Oscillation, Small mountainous rivers, Arid rivers, Environmental Engineering
Abstract

Previous estimations of sediment flux for the Salinas River of central California were based on data collected in the 1970s and assumptions of time invariant suspended sediment-discharge behavior. The goals of this study were to estimate sediment flux from the Salinas River using data from 1967-2011 by incorporating time dependent behavior and reassess the role of El Niño Southern Oscillation patterns in inter-decadal sediment load. This study builds on previous findings that time-dependent suspended sediment behavior in this system is controlled in part by antecedent hydrologic conditions. The condition of temporal dependence was further tested herein through comparison of flux estimates obtained using time-dependent formulations and a multivariate approach incorporating hydrologic factors. Longer sampling records and incorporation of decadal scale behavior or antecedent hydrologic conditions resulted in average annual load estimates of 2.0-2.9. Mt/yr with 95% confidence intervals of ±25 to 202%, in comparison to earlier estimates of ~3.3. Mt/yr. Previous overestimation of sediment load is due largely to the extrapolation of suspended sediment behavior from a decade of high sediment concentrations to the entire record, and the use of log-linear regression techniques on a non-linear system. The use of LOESS methods lowered QSS estimates and decreased confidence interval size. The inclusion of time-stratified and antecedent flow indices further decreased QSS estimates, but increased confidence interval size. However, temporal dependence of the CSS- Q relationship violates the assumptions of single base period regression, which suggests that time-stratified rating curves provide more realistic estimates of sediment flux means and uncertainty. The majority of suspended sediment was transported by flows of ~25-90 times mean discharge depending on transport constituent (fines or sand) and estimation method. Periods of differential suspended sediment behavior changed the relative importance of rare floods due to changes in the relationship of suspended sediment concentration vs. discharge. El Niño years dominated the sediment budget by producing on average ten times more sediment than non-El Niño years. Sediment load estimates provided further evidence that antecedent hydrologic conditions appear to have caused much of the temporal dependence of suspended sediment behavior.

Published
2015

107. The effect of El Niño Southern Oscillation cycles on the decadal scale suspended sediment behavior of a coastal dry‐summer subtropical catchment

Author

Gray, Andrew B, Pasternack, Gregory B, Watson, Elizabeth B, Warrick, Jonathan A, and Goñi, Miguel A

Subjects
suspended sediment, long-term memory, El Nino Southern Oscillation, arid rivers, non-stationarity, Geology, Physical Geography and Environmental Geoscience, Geography
Abstract

Rivers display temporal dependence in suspended sediment-water discharge relationships. Although most work has focused on multi-decadal trends, river sediment behavior often displays sub-decadal scale fluctuations that have received little attention. The objectives of this study were to identify inter-annual to decadal scale fluctuations in the suspended sediment-discharge relationship of a dry-summer subtropical river, infer the mechanisms behind these fluctuations, and examine the role of El Niño Southern Oscillation climate cycles. The Salinas River (California) is a moderate sized (11 000km2), coastal dry-summer subtropical catchment with a mean discharge (Qmean) of 11.6m3s-1. This watershed is located at the northern most extent of the Pacific coastal North America region that experiences increased storm frequency during El Niño years. Event to inter-annual scale suspended sediment behavior in this system was known to be influenced by antecedent hydrologic conditions, whereby previous hydrologic activity regulates the suspended sediment concentration-water discharge relationship. Fine and sand suspended sediment in the lower Salinas River exhibited persistent, decadal scale periods of positive and negative discharge corrected concentrations. The decadal scale variability in suspended sediment behavior was influenced by inter-annual to decadal scale fluctuations in hydrologic characteristics, including: elapsed time since small (~0.1×Qmean), and moderate (~10×Qmean) threshold discharge values, the number of preceding days that low/no flow occurred, and annual water yield. El Niño climatic activity was found to have little effect on decadal-scale fluctuations in the fine suspended sediment-discharge relationship due to low or no effect on the frequency of moderate to low discharge magnitudes, annual precipitation, and water yield. However, sand concentrations generally increased in El Niño years due to the increased frequency of moderate to high magnitude discharge events, which generally increase sand supply.

Published
2015

114. Embodied reflective practice : the embodied nature of reflection-in-action

Author

Gray, Andrew Lee

Subjects
707, 700 The arts, fine & decorative arts
Abstract

The purpose of this thesis is to examine the applicability of aspects of Schön’s (1983) theories of reflection-in-action in relation to visual art practice. Schön’s (1983) theories demonstrate that whilst they are written with design disciplines in mind, they do not extend to consider the appropriateness of its use in visual art practice. Scrivener (2000: 10) draws the distinction that whilst Schön’s (1983) use of scientific language in reflection-in-action is considered applicable for problem-solving projects in design, aspects of it are problematic for creative production research projects and recommends focusing reflection on the underlying experience of creative production. This thesis proposes that this and other issues, such as the emphasis on problem solving, and particularly, a reliance on a conversational metaphor, is likewise problematic for visual art practice. This thesis therefore moves to examine what is distinct about the application of reflective methods in visual art practice, in relation to design and research in the arts, through a series of text-based and documentary case studies. Analysis of the case studies suggest that there is an emphasis on embodiment essential to visual art processes, which is experiential in nature rather than problem-solving. A thorough examination of recent theories of embodied mind, which provide empirical evidence from a broad range of knowledge fields for the pervasive role of embodiment in shaping human experience, is presented. The primary research method is a review of two existing sets of theories and a synthesis of aspects of them in an original context, a process offered as an original contribution to knowledge. The context in question is the assessment of the applicability of the resulting synthesis to visual art practice, a domain for which neither theory was written. Knowing-in-action (Schön, 1983) describes the tacit knowing implicit in skillful performance when practice is going well, reflection-inaction (Schön, 1983) takes over, and describes the processes cycled through, only when problems are encountered in practice. Through an analysis of theories of embodied mind, and the documentary cases studies, the conclusion is drawn that in addition to these descriptions there is a rich layer of non-verbal embodied experience shaping action, conceptual meaning and verbal articulations of practice. This thesis therefore suggests modifications to theories of reflective practice in the visual arts, by incorporating theories of embodied mind in the development of additional reflective methods to supplement Schön’s theories (1983). Two methods are proposed as worthy of further study. The first researches Mark Johnson’s (1987) theory of metaphorical projection, which is presented as a means of mapping aspects of visual arts practitioners' verbal articulations of practice, back onto source domains in their embodied experiences of practice. The second explores a recommendation from within theories of embodied mind (Varela, Thompson and Rosch, 1993: 27) that mindfulness training could help develop a mindful, open-ended reflection. Taken together, this thesis proposes that an Embodied Reflective Practice could be developed to the benefit of visual art practitioners.

Published
2014

115. Sensory Loss and its Association with Different Types of Departures from the Labor Force Among Older Adults in the US

Author

Garcia Morales, Emmanuel E, Powel, Danielle S, Gray, Andrew, Assi, Lama, and Reed, Nicholas S

Abstract

To investigate the association between sensory loss and the timing and type of self-reported departures from the labor force, via retirement or disability, we used data from the Health and Retirement Study, cycles 2004–2018. Based on self-reported sensory loss, we classified individuals into four groups: no sensory loss, hearing loss only, vision loss only, and dual sensory loss (vision and hearing loss). We assumed that older adults could leave the labor force either by retirement or due to disability. Because once one type of exit is observed the other type cannot be observed, we implemented a competing risk approach to estimate the instantaneous rate of departure (sub-distribution hazard rate) for leaving the labor force due to disability, treating retirement as a competing risk, and for departures via retirement, with disability as the competing risk. We found that compared to older adults with no sensory loss, adults with vision loss are at a higher risk for leaving the labor force via disability (when treating retirement as a competing risk). Compared to no sensory loss, hearing loss was associated with a higher risk for retirement in models treating disability as a competing risk. Given the differences between disability and retirement benefits (before and after retirement age), policies intended to keep people with sensory loss from early labor force departures, such as accommodations in the workplace and/or hearing and vision care coverage, might contribute to better retiring conditions and healthy aging among older adults with sensory loss.

Published
2024
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116. Notes on Hybridization in Leaf frogs of the Genus Agalychnis (Anura, Hylidae, Phyllomedusinae)

Author

Gray, Andrew R.

Subjects
Quantitative Biology - Populations and Evolution
Abstract

Two species of Endangered Leaf frogs, Agalychnis moreletii and Agalychnis annae, belonging to the tree frog Subfamily Phyllomedusinae, Genus Agalychnis, were hybridized for the first time whilst being maintained in captivity. Previous to this, these allopatric Central American species were considered as being distinctly separate. Crossbreeding following genetic analysis reveals that the two species are extremely closely related, and the hybrid of A. moreletii and A. annae is presented for the first time. The importance of identifying degrees of genetic variation between species and different populations of the same species, for conservation purposes, is highlighted and discussed.

Published
2011

117. The DRAO Synthesis Telescope in the post-CGPS Era

Author

Kothes, Roland, Landecker, Tom L., and Gray, Andrew D.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - Galaxy Astrophysics
Abstract

The DRAO ST was used for the past 15 years as the primary instrument for the Canadian Galactic Plane Survey. This has been a spectacularly successful project, advancing our understanding of the Milky Way Galaxy through panoramic imaging of the main constituents of the Interstellar Medium. Observations for the CGPS are now complete and the Synthesis Telescope at DRAO has returned to proposal-driven mode. The Dominion Radio Astrophysical Observatory invites astronomers to apply for observing time with the DRAO Synthesis Telescope. The DRAO ST provides radio observations of atomic hydrogen and radio continuum emission, including the polarized signal, with high spatial dynamic range and arcminute resolution. Imaging techniques developed for the CGPS have made the telescope into a front-line instrument for wide-field imaging, particularly of polarized emission. We will discuss telescope characteristics, show examples of data to demonstrate the unique capabilities of the ST, and explain where and how to apply for observing time., Comment: 6 pages, 6 figures, to be published in ASP conference series: The Dynamic Interstellar Medium: A Celebration of the Canadian Galactic Plane Survey

Published
2010

119. The Performance of ChatGPT on Short-answer Questions in a Psychiatry Examination: A Pilot Study.

Author

Chao-Cheng Lin, Plooy, Kobus du, Gray, Andrew, Brown, Deirdre, Hobbs, Linda, Patterson, Tess, Tan, Valerie, Fridberg, Daniel, and Che-Wei Hsu

Subjects
CHATGPT, PSYCHIATRY, ARTIFICIAL intelligence, PSYCHIATRY education, ACCURACY
Abstract

Objectives: We compared ChatGPT’s performance to medical students’ on psychiatry examinations and investigated whether raters could distinguish answers between them. Methods: We used a copy of short-answer questions from a psychiatry examination to compare the performance of three randomized groups – ChatGPT, student, and hybrid (student-modified ChatGPT responses). Furthermore, we investigated raters’ ability to identify response origins. Results: ChatGPT-assisted answers, both ChatGPT alone (p < 0.001) and hybrid (p < 0.001), had significantly better examination performance than did independent students work. Raters showed high accuracy in identifying the origin of the responses, correctly identifying 92% of both students’ and ChatGPT-assisted responses. But raters were only 61% accurate in making the distinction between ChatGPT and hybrid answers. Conclusion: ChatGPT showed superior performance in a psychiatry examination compared to students’ work, but raters showed high accuracy in distinguishing them. Further investigation is warranted to optimize the advantages and mitigate the drawbacks of incorporating such technology into psychiatric education and health care. [ABSTRACT FROM AUTHOR]

Published
2024
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122. Use of historical isoscapes to develop an estuarine nutrient baseline

Author

Champlin, Lena K., primary, Woolfolk, Andrea, additional, Oczkowski, Autumn J., additional, Rittenhouse, Audrey, additional, Gray, Andrew B., additional, Wasson, Kerstin, additional, Rahman, Farzana I., additional, Zelanko, Paula, additional, Quintana Krupinski, Nadine B., additional, Jeppesen, Rikke, additional, Haskins, John, additional, and Watson, Elizabeth B., additional

Published
2023
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123. The influence of complex matrices on method performance in extracting and monitoring for microplastics

Author

Thornton Hampton, Leah M., primary, De Frond, Hannah, additional, Gesulga, Kristine, additional, Kotar, Syd, additional, Lao, Wenjian, additional, Matuch, Cindy, additional, Weisberg, Stephen B., additional, Wong, Charles S., additional, Brander, Susanne, additional, Christansen, Silke, additional, Cook, Cayla R., additional, Du, Fangni, additional, Ghosal, Sutapa, additional, Gray, Andrew B., additional, Hankett, Jeanne, additional, Helm, Paul A., additional, Ho, Kay T., additional, Kefela, Timnit, additional, Lattin, Gwendolyn, additional, Lusher, Amy, additional, Mai, Lei, additional, McNeish, Rachel E., additional, Mina, Odette, additional, Minor, Elizabeth C., additional, Primpke, Sebastian, additional, Rickabaugh, Keith, additional, Renick, Violet C., additional, Singh, Samiksha, additional, van Bavel, Bert, additional, Vollnhals, Florian, additional, and Rochman, Chelsea M., additional

Published
2023
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124. Intravenous aviptadil and remdesivir for treatment of COVID-19-associated hypoxaemic respiratory failure in the USA (TESICO): a randomised, placebo-controlled trial

Author

Brown, Samuel M, primary, Barkauskas, Christina E, additional, Grund, Birgit, additional, Sharma, Shweta, additional, Phillips, Andrew N, additional, Leither, Lindsay, additional, Peltan, Ithan D, additional, Lanspa, Michael, additional, Gilstrap, Daniel L, additional, Mourad, Ahmad, additional, Lane, Kathleen, additional, Beitler, Jeremy R, additional, Serra, Alexis L, additional, Garcia, Ivan, additional, Almasri, Eyad, additional, Fayed, Mohamed, additional, Hubel, Kinsley, additional, Harris, Estelle S, additional, Middleton, Elizabeth A, additional, Barrios, Macy A G, additional, Mathews, Kusum S, additional, Goel, Neha N, additional, Acquah, Samuel, additional, Mosier, Jarrod, additional, Hypes, Cameron, additional, Salvagio Campbell, Elizabeth, additional, Khan, Akram, additional, Hough, Catherine L, additional, Wilson, Jennifer G, additional, Levitt, Joseph E, additional, Duggal, Abhijit, additional, Dugar, Siddharth, additional, Goodwin, Andrew J, additional, Terry, Charles, additional, Chen, Peter, additional, Torbati, Sam, additional, Iyer, Nithya, additional, Sandkovsky, Uriel S, additional, Johnson, Nicholas J, additional, Robinson, Bryce R H, additional, Matthay, Michael A, additional, Aggarwal, Neil R, additional, Douglas, Ivor S, additional, Casey, Jonathan D, additional, Hache-Marliere, Manuel, additional, Georges Youssef, J, additional, Nkemdirim, William, additional, Leshnower, Brad, additional, Awan, Omar, additional, Pannu, Sonal, additional, O'Mahony, Darragh Shane, additional, Manian, Prasad, additional, Awori Hayanga, J W, additional, Wortmann, Glenn W, additional, Tomazini, Bruno M, additional, Miller, Robert F, additional, Jensen, Jens-Ulrik, additional, Murray, Daniel D, additional, Bickell, Nina A, additional, Zatakia, Jigna, additional, Burris, Sarah, additional, Higgs, Elizabeth S, additional, Natarajan, Ven, additional, Dewar, Robin L, additional, Schechner, Adam, additional, Kang, Nayon, additional, Arenas-Pinto, Alejandro, additional, Hudson, Fleur, additional, Ginde, Adit A, additional, Self, Wesley H, additional, Rogers, Angela J, additional, Oldmixon, Cathryn F, additional, Morin, Haley, additional, Sanchez, Adriana, additional, Weintrob, Amy C, additional, Cavalcanti, Alexandre Biasi, additional, Davis-Karim, Anne, additional, Engen, Nicole, additional, Denning, Eileen, additional, Taylor Thompson, B, additional, Gelijns, Annetine C, additional, Kan, Virginia, additional, Davey, Victoria J, additional, Lundgren, Jens D, additional, Babiker, Abdel G, additional, Neaton, James D, additional, Lane, H Clifford, additional, Tierney, John, additional, Vogel, Susan E., additional, McNay, Laura A., additional, Cahill, Kelly, additional, Crew, Page, additional, Sardana, Ratna, additional, Segal Raim, Sharo, additional, Shaw-Saliba, Katy, additional, Atri, Negin, additional, Miller, Mark, additional, Vallee, David, additional, Chung, Lucy, additional, Delph, Yvette, additional, Adam, Stacey J., additional, Read, Sarah, additional, Draghia-Akli, Ruxandra, additional, Harrigan, Rachel, additional, Carlsen, Amy, additional, Carter, Anita, additional, DuChene, Alain, additional, Eckroth, Kate, additional, Frase, Alex, additional, Harrison, Merrie, additional, Meger, Sue, additional, Quan, Kien, additional, Quan, Siu Fun, additional, Reilly, Cavan, additional, Thompson, Greg, additional, Walski, Jamie, additional, Moskowitz, Alan J., additional, Bagiella, Emilia, additional, Moquete, Ellen, additional, O'Sullivan, Karen, additional, Marks, Mary E., additional, Accardi, Evan, additional, Kinzel, Emily, additional, Bedoya, Gabriela, additional, Gupta, Lopa, additional, Overbey, Jessica R., additional, Padillia, Maria L., additional, Santos, Milerva, additional, Gillinov, Marc A., additional, Miller, Marissa A., additional, Taddei-Peters, Wendy C., additional, Fenton, Kathleen, additional, Smith, Peter K., additional, Vekstein, Andrew M., additional, Ko, Emily R., additional, Al-Hegelan, Mashael S., additional, McGowan, Lauren M., additional, Motta, Mary, additional, Howell, Shauna, additional, Bent, Francine, additional, Kalager, Rachel, additional, Chan, Emmanuel, additional, Aloor, Heather L., additional, Griffin, S. Michelle, additional, Covington, Anna, additional, McLendon-Arvik, Beth, additional, Bussadori, Barbara, additional, Miller-Bell, Mary, additional, Sampey, Cathy, additional, Gaver, Vincent, additional, Hollister, Beth A., additional, Giangiacomo, Dana M., additional, Pauley, Alena, additional, Patel, Aashay, additional, Classon, Chris, additional, Frazier, Madison, additional, Osborne, Robyn, additional, Conlon, Debbi H., additional, Joshi, Marybeth, additional, Gottlieb, Robert L., additional, Mack, Michael, additional, Berhe, Mezgebe, additional, Haley, Clinton, additional, Dishner, Emma, additional, Bettacchi, Christopher, additional, Golden, Kevin, additional, Duhaime, Erin, additional, Ryan, Madison, additional, Tallmadge, Catherine, additional, Estrada, Lorie, additional, Jones, Felecia, additional, Villa, Samantha, additional, Wang, Samantha, additional, Robert, Raven, additional, Coleman, Tanquinisha, additional, Clariday, Laura, additional, Baker, Rebecca, additional, Hurutado-Rodriguez, Mariana, additional, Iram, Nazia, additional, Fresnedo, Michelle, additional, Davis, Allyson, additional, Leonard, Kiara, additional, Ramierez, Noelia, additional, Thammavong, Jon, additional, Duque, Krizia, additional, Turner, Emma, additional, Fisher, Tammy, additional, Robinson, Dianna, additional, Ransom, Desirae, additional, Maldonado, Nicholas, additional, Lusk, Erica, additional, Killian, Aaron, additional, Palacios, Adriana, additional, Solis, Edilia, additional, Jerrow, Janet, additional, Watts, Matthew, additional, Whitacre, Heather, additional, Cothran, Elizabeth, additional, Bender, William, additional, Miller, Jeffrey, additional, Nugent, Katherine, additional, Farrington, Woodrow, additional, Baio, Kim T., additional, McBride, Mary K., additional, Fielding, Michele, additional, Mathewson, Sonya, additional, Porte, Kristina, additional, Haley, Elizabeth, additional, Rogers, Susan, additional, Tyler, Derrick, additional, Perin, Emerson, additional, Costello, Briana, additional, Postalian, Alexander, additional, Sohail, Rizwan, additional, Hinsu, Punit, additional, Watson, Carolyn, additional, Kappenman, Casey, additional, Chen, James, additional, Walker, Kim, additional, Fink, Melyssa, additional, Phillip, Gabrielle, additional, Mahon, Kim, additional, Sturgis, Lydia, additional, Maher, Patrick, additional, Rogers, Linda, additional, Ng, Nicole, additional, Marshall, Jason, additional, Bassily-Marcus, Adel, additional, Cohen, Ivy, additional, Ramoo, Shamini, additional, Malhotra, Aryan, additional, Kessler, Jonathan, additional, Goetz, Rebekah, additional, Badhwar, Vinay, additional, Hayanga, Jeremiah, additional, Giblin Sutton, Lisa, additional, Williams, Roger, additional, Berry Bartolo, Elizabeth, additional, Walker, Dmitry, additional, Bunner, Robin, additional, Glaze, Chad, additional, Aucremanne, Tanja, additional, Bishop, James, additional, Kelley, Macey, additional, Peterson, Autumn, additional, Sauerborn, Erica, additional, Reckart, Robin, additional, Miller, Brittany, additional, Mittel, Aaron, additional, Darmanian, Anita, additional, Rosen, Amanda, additional, Madahar, Purnema, additional, Schicchi, John, additional, Gosek, Katarzyna, additional, Dzierba, Amy, additional, Wahab, Romina, additional, Eng, Connie, additional, Al-Saadi, Mukhtar, additional, Zahiruddin, Faisal, additional, Syed, Mohi, additional, George, Michael, additional, Patel, Varsha, additional, Onwunyi, Chisom, additional, Barroso da Costa, Rosa, additional, North, Crystal, additional, Ringwood, Nancy, additional, Fitzgerald, Laura, additional, Muzikansky, Ariela, additional, Morse, Richard, additional, Brower, Roy G., additional, Reineck, Lora A., additional, Bienstock, Karen, additional, Hou, Peter, additional, Steingrub, Jay S., additional, Tidswell, Mark A., additional, Kozikowski, Lori-Ann, additional, Kardos, Cynthia, additional, De Souza, Leslie, additional, Talmor, Daniel, additional, Shapiro, Nathan, additional, Hibbert, Kathryn, additional, Brait, Kelsey, additional, Kone, Mamary, additional, Hendey, Gregory, additional, Kangelaris, Kirsten N., additional, Ashktorab, Kimia, additional, Gropper, Rachel, additional, Agrawal, Anika, additional, Timothy, Kelly, additional, Zhou, Hanjing, additional, Hughes, Alyssa, additional, Garcia, Rebekah, additional, Torres, Adrian, additional, Hernandez-Almaraz, Maria Elena, additional, Vojnik, Rosemary, additional, Perez, Cynthia, additional, McDowell, Jordan, additional, Chang, Steven Y., additional, Vargas, Julia, additional, Moss, Marc, additional, McKeehan, Jeffrey, additional, Higgins, Carrie, additional, Johnson, Emily, additional, Slaughter, Suzanne, additional, Wyles, David, additional, Hiller, Terra, additional, Oakes, Judy, additional, Garcia, Ana, additional, Gravitz, Stephanie, additional, Lyle, Carolynn, additional, Swanson, Diandra, additional, Gong, Michelle Ng., additional, Richardson, Lynnne D., additional, Chen, Jen-Ting, additional, Moskowitz, Ari, additional, Mohamed, Amira, additional, Lopez, Brenda, additional, Amosu, Omowunmi, additional, Tzehaie, Hiwet, additional, Boujid, Sabah, additional, Bixby, Billie, additional, Lopez, Anitza A., additional, Durley, JaVon, additional, Gilson, Boris, additional, Hite, R. Duncan, additional, Wang, Henry, additional, Wiedemann, Hebert P., additional, Mehkri, Omar, additional, Ashok, Kiran, additional, King, Alexander, additional, Brennan, Connery, additional, Exline, Matthew C., additional, Englert, Joshua A., additional, Karow, Sarah, additional, Schwartz, Elizabeth, additional, So, Preston, additional, So, Madison, additional, Krol, Olivia F., additional, Briceno Parra, Genesis I., additional, Mills, Emmanuel Nii Lantei, additional, Oh, Minn, additional, Pena, Jose, additional, Martínez, Jesús Alejandro, additional, Jackman, Susan E., additional, Bayoumi, Emad, additional, Pascual, Ethan, additional, Caudill, Antonina, additional, Chen, Po-En, additional, Richardson, Tabia, additional, Clapham, Gregg J., additional, Herrera, Lisa, additional, Ojukwu, Cristabelle, additional, Fine, Devin, additional, Gomez, Millie J., additional, Choi-Kuaea, Yunhee, additional, Weissberg, Gwendolyn, additional, Isip, Katherine, additional, Mattison, Brittany, additional, Tran, Dana, additional, Emilov Dukov, Jennifer, additional, Chung, Paul, additional, Kang, Bo Ran, additional, Escobar, Lauren, additional, Tran, Trung, additional, Baig, Saba, additional, Wallick, Julie A., additional, Duven, Alexandria M., additional, Fletcher, Dakota D., additional, Gundel, Stephanie, additional, Fuentes, Megan, additional, Newton, Maranda, additional, Peterson, Emily, additional, Jiang, Kelsey, additional, Files, D. Clark, additional, Miller, Chadwick, additional, Lematty, Caitlin, additional, Rasberry, April, additional, Warden, Ashley, additional, Bledsoe, Joseph, additional, Knowlton, Kirk, additional, Knox, Daniel B., additional, Klippel, Carolyn, additional, Armbruster, Brent P., additional, Applegate, Darrin, additional, Imel, Karah, additional, Fergus, Melissa, additional, Rahmati, Kasra, additional, Jensen, Hannah, additional, Aston, Valerie T., additional, Jeppson, Joshua, additional, Marshall, J. Hunter, additional, Lumpkin, Jenna, additional, Smith, Cassie, additional, Burke, Tyler, additional, Gray, Andrew, additional, Paine, Robert, additional, Callahan, Sean, additional, Yamane, Misty, additional, Waddoups, Lindsey, additional, Rice, Todd W., additional, Johnson, Jakea, additional, Gray, Christopher, additional, Hays, Margaret, additional, Roth, Megan, additional, Musick, Sarah, additional, Miller, Karen, additional, Semler, Matthew W., additional, Popielski, Laura, additional, Kambo, Amy, additional, Viens, Kimberly, additional, Turner, Melissa, additional, Vjecha, Michael J., additional, Denyer, Rachel, additional, Khosla, Rahul, additional, Rajendran, Bindu, additional, Gonzales, Melissa, additional, Moriarty, Theresa, additional, Biswas, Kousick, additional, Harrington, Cristin, additional, Garcia, Amanda, additional, Bremer, Tammy, additional, Burke, Tara, additional, Koker, Brittany, additional, Pittman, David, additional, Vasudeva, Shikha S., additional, Anholm, James D., additional, Specht, Lennard, additional, Rodriguez, Aimee, additional, Ngo, Han, additional, Duong, Lien, additional, Previte, Matthew, additional, Raben, Dorthe, additional, Nielsen, Charlotte B., additional, Friis Larsen, Jakob, additional, Peters, Lars, additional, Matthews, Gail, additional, Kelleher, Anthony, additional, Polizzotto, Mark, additional, Carey, Catherine, additional, Chang, Christina, additional, Dharan, Nila, additional, Hough, Sally, additional, Virachit, Sophie, additional, Davidson, Sarah, additional, Bice, Daniel J., additional, Ognenovska, Katherine, additional, Cabrera, Gesalit, additional, Flynn, Ruth, additional, Abdelghany, Mazin, additional, Baseler, Beth, additional, Teitelbaum, Marc, additional, Holley, H. Preston, additional, Jankelevich, Shirley, additional, Adams, Amy, additional, Becker, Nancy, additional, Doleny, Suzanne, additional, Hissey, Debbie, additional, Simpson, Shelly, additional, Kim, Mi Ha, additional, Beeler, Joy, additional, Harmon, Liam, additional, Vanderpuye, Sharon, additional, Yeon, Lindsey, additional, Frye, Leanna, additional, Rudzinski, Erin, additional, Buehn, Molly, additional, Eccard-Koons, Vanessa, additional, Frary, Sadie, additional, MacDonalad, Leah, additional, Cash, Jennifer, additional, Hoopengardner, Lisa, additional, Linton, Jessica, additional, Nelson, Michaela, additional, Spinelli-Nadzam, Mary, additional, Proffitt, Calvin, additional, Lee, Christopher, additional, Engel, Theresa, additional, Fontaine, Laura, additional, Osborne, CK, additional, Hohn, Matt, additional, Galcik, Michael, additional, Thompson, DeeDee, additional, Sandrus, Jen, additional, Manchard, Jon, additional, Giri, Jiwan, additional, Kopka, Stacy, additional, Chang, Weizhong, additional, Sherman, Brad T., additional, Rupert, Adam W., additional, Highbarger, Helene, additional, Baseler, Michael, additional, Lallemand, Perrine, additional, Rehman, Tauseef, additional, Imamichi, Tom, additional, Laverdure, Sylvain, additional, Paudel, Sharada, additional, Cook, Kyndal, additional, Haupt, Kendra, additional, Hazen, Allison, additional, Badralmaa, Yunden, additional, Highbarger, Jeroen, additional, McCormack, Ashley, additional, Gerry, Norman P., additional, Smith, Kenneth, additional, Patel, Bhakti, additional, Domeraski, Nadia, additional, Hoover, Marie L., additional, DuChateau, Nadine, additional, Flosi, Adam, additional, Nelson, Rich, additional, Stojanovic, Jelena, additional, and Wenner, Christine, additional

Published
2023
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138. Exploring gas-phase ionic liquid aggregates by mass spectrometry and computational chemistry

Author

Gray, Andrew Peter, Campbell, Eleanor., Camp, Philip., and Duncombe, Bridgette

Subjects
541, ionic liquid, mass spectrometry, computational chemistry
Abstract

Ionic liquids (IL) are salts which are liquid at low temperatures, typically with melting points under 100 °C. In recent years ILs have been treated as novel solvents and used in a wide variety of applications such as analytical and separation processes, electrochemical devices and chemical syntheses. The properties of many ILs have been extensively studied; these studies have primarily focused on the investigation of key physical properties including viscosity, density and solubility. This thesis presents mass spectrometry (MS) and computational data to investigate the intrinsic interactions between a small number of IL ions and also their interactions with contaminants. MS was used to study gas-phase aggregates of three ILs based on the 1-butyl-3- methylimidazolium (C4mim+) cation. The influence of different ion sources was investigated on C4mimCl. Conventional electrospray ionisation (ESI) and nano-ESI techniques were compared with recently developed sonic-spray ionisation (SSI) and plasma assisted desorption ionisation (PADI). SSI was found to be beneficial to the formation of larger aggregates while PADI was significantly less efficient. Gas-phase structures of the singly charged cationic aggregates of C4mimCl were characterised with the aid of collision induced dissociation (CID) and density functional theory (DFT) calculations. Additionally, CID and DFT gave consistent results for the relative stability of the C4mimCl aggregates, showing a good agreement between experiment and theory. Mixed solutions of C4mimCl with a range of metal chloride salts were used to form aggregates incorporating both IL and metal chlorides. LiCl, NaCl, KCl, CsCl, MgCl2 and ZnCl2 were all combined with C4mimCl. Magic number characteristics were observed for a number of pure IL and mixed aggregates. Many of the mixed species were characterised using MS and DFT calculations. In particular, the relative stabilities were determined and the structures of the aggregates were calculated. It was found that the metal ions would normally act as a core for the aggregates with the stability determined by the metal-chlorine binding strength and the steric hindrance of the aggregates. It was necessary to exploit pseudopotentials as opposed to all-electron basis sets for the larger aggregates and aggregates containing heavy atoms. While water is a very effective contaminant for ILs it was not possible to observe gas-phase IL aggregates incorporating this despite using multiple methods. Additionally the presence of protonated aggregates was likewise not observed throughout the range of experiments. Possible structures where these features would be incorporated were studied with DFT to obtain some insight into their lack of formation.

Published
2012

142. 'Observation Has Set In': Comparing Students and Peers as Reviewers of Teaching

Author

Huxham, Mark, Scoles, Jenny, Green, Ursula, Purves, Samantha, Welsh, Zoe, and Gray, Andrew

Abstract

Peer review is a powerful method to enhance teaching in higher education. Peers, however, may not be the most relevant people in evaluating teaching success; as the most important stakeholders in learning, students' evaluations need to be heard. Whilst some efforts to capture "the student voice" are simplistic and may foster consumerist approaches, adopting "radical collegiality" towards students may provide the benefits of peer review whilst avoiding some of its disadvantages. Here we describe the Students as Colleagues project, which trained student volunteers as evaluators of teaching. To assess the ability of students to provide useful reviews, we compared their evaluative feedback with that from academic peers, using a paired design and qualitative and quantitative data. Students gave significantly more positive comments, and just as many negative and directive comments, as academic peers. Student colleagues emphasised the positive personal (rather than professional) capacities of their reviewees, encouraged expressed vulnerability and drew on their broad experiences as students rather than from professional perspectives. Participation changed how students saw their abilities and helped "humanise" both the reviewees and the university as a whole. Our results and standpoint theory suggest that students' evaluative feedback is the most valuable perspective to inform teaching enhancement.

Published
2017
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143. Investigation into the fate and transport in groundwater of agriculturally derived phosphorus compounds

Author

Gray, Andrew

Abstract

Investigation into the fate and transport in groundwater of agriculturally derived phosphorus compounds Phosphates are ubiquitous in the environment, where they are essential for life however at excessive levels they can cause significant environmental damage. This project investigates the spatial and temporal occurrence of phosphorus in groundwater, and phosphorus transport through the vadose zone. Concentrating on agriculturally-derived phosphates, the research elucidates the geochemical relationships between phosphorus species and geology. The project has two study locations. A section of the Lower Usk Valley in Monmouthshire was the principal site the Eden Valley in Cumbria was used as a comparison case study. With highly heterogeneous distributions, phosphorus often showed significant concentrations in both soil and groundwater. In groundwater Soluble Reactive Phosphorus (SRP) ranged from 1.07 mg I"1 to undetectable. Maximum soil leachable SRP was measured at 55 mg kg"1 and soil Total Phosphorus (TP) 113 mg kg"1 while in an adjacent borehole groundwater SRP was undetectable. Phosphorus was found at intermediate concentrations beneath potential hotspots created by large manure piles effluent 85 mg I"1. Analysis by X-ray diffraction and analytical scanning electron microscopy did not identify soil phosphate minerals at these and other sites this suggests that precipitation reactions are not a dominant source or sink of agricultural phosphorus in local soils. The results of the geochemical investigations indicates that iron and manganese oxides are providing sorption sites for phosphates, influencing their mobility and observed concentration in groundwater. Data obtained from in-situ borehole loggers were used to characterise the aquifer zone of the study area and understand the groundwater response to external drivers such as fertilizer application and rainfall. Groundwater and species transport modelling of the Usk area indicates that local parameter heterogeneity is critically important. The groundwater modelling, supported by a statistical analysis of the data, has increased and refined our conceptual understanding of the fate and transport of phosphorus in groundwater.

Published
2011

144. Estimating individual-tree aboveground biomass of tree species in the western U.S.A

Author

Poudel, Krishna P., Temesgen, Hailemariam, Radtke, Philip J., and Gray, Andrew N.

Subjects
Customer relationship management software -- Usage, Forest reserves, Customer relationship management software, Earth sciences
Abstract

Using a large dataset compiled from studies over the years covering 23 tree species, we developed methods to estimate total and components (stem, bark, branch, and foliage) of aboveground live tree biomass. Missing components in the dataset were imputed using species-specific or generalized (species combined into softwood and hardwood groups) Dirichlet imputation. Geometric means of the imputed stem wood proportions were 8% and 9% higher than the observed geometric mean of stem wood proportions in softwood and hardwood species, respectively. For other components, the differences were within 1%. On average, the component ratio method (CRM), used for the official United States forest carbon inventories, underestimated the aboveground biomass (AGB, kg) predictions by 3.7% with a very wide range (-70.3% to 31.6%). Compared with the CRM approach, equations developed in this study reduced RMSE of AGB by as much as 145.0%. On average, new equations reduced RMSE in predicting individual-tree AGB by 15.5% compared with the CRM approach and by 3.9% compared with a calibration of CRM AGB. Predicting AGB as a function of stem volume was not as accurate as using direct AGB equations. Generalized component ratio equations may be suitable for the stem wood component but were highly biased for other components. Key words: biomass, western United States, Dirichlet imputation, component ratio method, carbon. A l'aide d'un important jeu de donnees compilees a partir d'etudes couvrant plusieurs annees et 23 especes d'arbres, nous avons elabore des methodes pour estimer la biomasse aerienne totale et ses composantes (fut, ecorce, branches et feuillage) chez les arbres vivants. Les composantes manquantes dans le jeu de donnees ont ete imputees en utilisant la methode de Dirichlet individuellement pour chaque espece ou collectivement en formant un groupe pour les especes resineuses et un autre pour les especes feuillues. Les moyennes geometriques imputees des proportions de bois de fut etaient respectivement 8 et 9 % plus elevees que les moyennes geometriques observees des proportions de bois de fut chez les especes resineuses et feuillues. Dans le cas des autres composantes, les differences etaient en deca de 1 %. En moyenne, la methode des ratios des composantes (MRC), utilisee pour les inventaires officiels du carbone forestier aux Etats-Unis, sous-estimait les predictions de biomasse aerienne (BA, kg) de 3,7 % avec un tres grand ecart (-70,3 a 31,6 %). Comparativement a la MRC, les equations elaborees dans cette etude ont reduit l'erreur quadratique moyenne (EQM) de la BA jusqu'a 145,0 %. En moyenne, les nouvelles equations pour predire la BA d'arbres individuels ont reduit l'EQM de 15,5 % comparativement a la MRC, et de 3,9 % comparativement a une calibration de la BA par la MRC. La prediction de la BA en fonction du volume du fut n'etait pas aussi precise que l'utilisation directe des equations de la BA. Les equations generalisees du ratio des composantes peuvent convenir pour la composante du bois de fut mais elles etaient fortement biaisees pour les autres composantes. [Traduit par la Redaction] Mots-cles : biomasse, ouest des Etats-Unis, imputation par la methode de Dirichlet, methode des ratios des composantes, carbone., Introduction Forest biomass is important commercially for fuelwood and fiber production and scientifically for studies of ecosystem productivity (Parresol 1999). It is also useful in quantifying carbon stocks and sequestration [...]

Published
2019
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148. Damage control orthopaedics and the cognitive effects of cerebral fat embolus

Author

Gray, Andrew Colin

Subjects
617
Abstract

This thesis consists of two clinical projects and a large animal (ovine) model of severe musculoskeletal trauma under terminal anaesthesia. It involved the analysis of haemodynamic, pulmonary embolic, coagulative and inflammatory response to bilateral femoral fractures and hypovolaemic shock comparing two different surgical strategies of fracture fixation (damage control versus early total care). This study aimed to better quantify the relative consequences of initial surgical management (external fixation versus intramedullary stabilisation) against a background of relative severe injury. Both clinical projects involved the use of Transcranial Doppler ultrasound monitoring of the cerebral circulation to quantify the cerebral embolic load, with detailed clinical cognitive testing and the measurement of a serum marker (S100B protein) of neuronal injury. One study involved trauma patients requiring intramedullary stabilisation of femoral and tibial diaphyseal fractures and the other examined patients undergoing primary lower limb arthroplasty. The primary aim of both studies was to accurately quantify cognitive change following surgery and to assess whether these measurements correlated with intraoperative cerebral embolic load and serum S100B protein concentrations following surgery. The animal study demonstrated a higher pulmonary embolic load with early intramedullary femoral fracture fixation compared to external fixation. However the initial fracture fixation method did not affect animal mortality or changes seen in the measured coagulation and inflammatory markers. Specific and quantifiable defects in cognitive function occurred following surgery in both clinical studies. However, no direct correlation was found between cognitive change and cerebral emboli detection. Altering surgical technique can reduce the embolic load. However a linear correlation between embolic load and clinical outcome was not established.

Published
2007

149. Mechanosensitivity during lower extremity neurodynamic testing is diminished in individuals with Type 2 Diabetes Mellitus and peripheral neuropathy: a cross sectional study

Author

Boyd, Benjamin S, Wanek, Linda, Gray, Andrew T, and Topp, Kimberly S

Abstract

Abstract Background Type 2 Diabetes Mellitus (T2DM) and diabetic symmetrical polyneuropathy (DSP) impact multiple modalities of sensation including light touch, temperature, position sense and vibration perception. No study to date has examined the mechanosensitivity of peripheral nerves during limb movement in this population. The objective was to determine the unique effects T2DM and DSP have on nerve mechanosensitivity in the lower extremity. Methods This cross-sectional study included 43 people with T2DM. Straight leg raise neurodynamic tests were performed with ankle plantar flexion (PF/SLR) and dorsiflexion (DF/SLR). Hip flexion range of motion (ROM), lower extremity muscle activity and symptom profile, intensity and location were measured at rest, first onset of symptoms (P1) and maximally tolerated symptoms (P2). Results The addition of ankle dorsiflexion during SLR testing reduced the hip flexion ROM by 4.3° ± 6.5° at P1 and by 5.4° ± 4.9° at P2. Individuals in the T2DM group with signs of severe DSP (n = 9) had no difference in hip flexion ROM between PF/SLR and DF/SLR at P1 (1.4° ± 4.2°; paired t-test p = 0.34) or P2 (0.9° ± 2.5°; paired t-test p = 0.31). Movement induced muscle activity was absent during SLR with the exception of the tibialis anterior during DF/SLR testing. Increases in symptom intensity during SLR testing were similar for both PF/SLR and DF/SLR. The addition of ankle dorsiflexion induced more frequent posterior leg symptoms when taken to P2. Conclusions Consistent with previous recommendations in the literature, P1 is an appropriate test end point for SLR neurodynamic testing in people with T2DM. However, our findings suggest that people with T2DM and severe DSP have limited responses to SLR neurodynamic testing, and thus may be at risk for harm from nerve overstretch and the information gathered will be of limited clinical value.

Published
2010

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