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3. Notes

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

7. Index

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

8. Cover

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

12. Encores

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

14. Acknowledgments

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

15. Half Title Page

Author

Brown, Thomas J. and Harrison, Carol E.

Published
2024

20. The genomes of all lungfish inform on genome expansion and tetrapod evolution

Author

Schartl, Manfred, Woltering, Joost M., Irisarri, Iker, Du, Kang, Kneitz, Susanne, Pippel, Martin, Brown, Thomas, Franchini, Paolo, Li, Jing, Li, Ming, Adolfi, Mateus, Winkler, Sylke, de Freitas Sousa, Josane, Chen, Zhuoxin, Jacinto, Sandra, Kvon, Evgeny Z., Correa de Oliveira, Luis Rogério, Monteiro, Erika, Baia Amaral, Danielson, Burmester, Thorsten, Chalopin, Domitille, Suh, Alexander, Myers, Eugene, Simakov, Oleg, Schneider, Igor, and Meyer, Axel

Published
2024
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24. An Evaluation of Agreement of Breathing Rates Measured by a Novel Device, Manual Counting, and Other Techniques Used in Clinical Practice: Protocol for the Observational VENTILATE Study

Author

Jones, Matthew T, Heiden, Emily, Fogg, Carole, Meredith, Paul, Smith, Gary, Sayer, Nicola, Toft, Lisa, Williams, Emma, Williams, Matthew, Brown, Thomas, Gates, Jessica, Lodge, David, Bassett, Paul, Amos, Mark, Chauhan, Milan, Begum, Selina, Rason, Madeleine, Winter, Jonathan, Longstaff, Jayne, and Chauhan, Anoop J

Subjects
Medicine, Computer applications to medicine. Medical informatics, R858-859.7
Abstract

BackgroundRespiratory rate (RR) is the most sensitive physiological observation to predict clinical deterioration on hospital wards, and poor clinical monitoring has been highlighted as a primary contributor to avoidable mortality. Patients in intensive care have their RR monitored continuously, but this equipment is rarely available on general hospital wards. ObjectiveThe primary objective is to assess the accuracy of the RespiraSense device in comparison with other methods currently used in clinical practice. The secondary objective is to assess the accuracy of the RespiraSense device in participants in different positions and when reading aloud. MethodsA single-center, prospective observational study will investigate the agreement of the RespiraSense device as compared with other device measurements (capnography, electrocardiogram) and the current standard measurement of RR (manual counting by a trained health care professional). The different methods will be employed concurrently on the same participant as part of a single study visit. ResultsRecruitment to this study has not yet started as funding decisions are still pending. Therefore, results are not available at this stage. It is anticipated that the data required could be collected within 2 months of first recruitment to the study and data analysis completed within 6 months of the study start date. ConclusionsThe Evaluation of Agreement of Breathing Rates Measured by a Novel Device, Manual Counting, and Other Techniques Used in Clinical Practice (VENTILATE) study will provide further validation of the use of the RespiraSense device in subjects with abnormal respiratory rates. International Registered Report Identifier (IRRID)PRR1-10.2196/15437

Published
2020
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27. A device for magnetic-field angle control in magneto-optical filters using a solenoid-permanent magnet pair

Author

Alqarni, Sharaa A., Briscoe, Jack D., Higgins, Clare R., Logue, Fraser D., Pizzey, Danielle, Robertson-Brown, Thomas G., and Hughes, Ifan G.

Subjects
Physics - Optics, Physics - Instrumentation and Detectors
Abstract

Atomic bandpass filters are used in a variety of applications due to their narrow bandwidths and high transmission at specific frequencies. Predominantly these filters in the Faraday (Voigt) geometry, using an applied axial(transverse) magnetic field with respect to the laser propagation direction. Recently, there has been interest in filters realized with arbitrary-angle magnetic fields, which have been made by rotating permanent magnets with respect to the $k$-vector of the interrogating laser beam. However, the magnetic-field angle achievable with this method is limited as field uniformity across the cell decreases as the rotation angle increases. In this work, we propose and demonstrate a new method of generating an arbitrary-angle magnetic field, using a solenoid to produce a small, and easily alterable, axial field, in conjunction with fixed permanent magnets to produce a large transverse field. We directly measure the fields produced by both methods, finding them to be very similar over the length of the vapor cell. We then compare the transmission profiles of filters produced using both methods, again finding excellent agreement. Finally, we demonstrate the sensitivity of filter profile to changing magnetic-field angle (solenoid current), which becomes easier to exploit with the much improved angle control and precision offered by our new design., Comment: 8 pages, 6 figures

Published
2023
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30. Optimisation and artifacts of photothermal excitation of microresonators

Author

Ge, Liping Kevin, Tuniz, Alessandro, de Sterke, Martijn, Zavislan, James M., Brown, Thomas G., Martin, Sascha, and Martinez-Martin, David

Subjects
Physics - Applied Physics, Physics - Optics
Abstract

The excitation of microresonators using focused intensity modulated light, known as photothermal excitation, is gaining significant attention due to its capacity to accurately excite microresonators without distortions, even in liquid environments, which is driving key advancements in atomic force microscopy and related technologies. Despite progress in the development of coatings, the conversion of light into mechanical movement remains largely inefficient, limiting resonator movements to tens of nanometres even when milliwatts of optical power are used. Moreover, how photothermal efficiency depends on the relative position of a microresonator along the propagation axis of the photothermal beam remains poorly studied, hampering our understanding of the conversion of light into mechanical motion. Here, we perform photothermal measurements in air and water using cantilever microresonators and a custom-built picobalance, and determine how photothermal efficiency changes along the propagation beam axis. We identify that far out-of-band laser emission can lead to visual misidentification of the beam waist, resulting in a drop of photothermal efficiency of up to one order of magnitude. Our measurements also unveil that the beam waist is not always the position of highest photothermal efficiency, and can reduce the efficiency up to 20% for silicon cantilevers with trapezoidal cross section., Comment: 30 pages, 4 figures, 1 table and supplementary information

Published
2023

31. Roadmap on energy harvesting materials

Author

Pecunia, Vincenzo, Silva, S Ravi P, Phillips, Jamie D, Artegiani, Elisa, Romeo, Alessandro, Shim, Hongjae, Park, Jongsung, Kim, Jin Hyeok, Yun, Jae Sung, Welch, Gregory C, Larson, Bryon W, Creran, Myles, Laventure, Audrey, Sasitharan, Kezia, Flores-Diaz, Natalie, Freitag, Marina, Xu, Jie, Brown, Thomas M, Li, Benxuan, Wang, Yiwen, Li, Zhe, Hou, Bo, Hamadani, Behrang H, Defay, Emmanuel, Kovacova, Veronika, Glinsek, Sebastjan, Kar-Narayan, Sohini, Bai, Yang, Bin Kim, Da, Cho, Yong Soo, Žukauskaitė, Agnė, Barth, Stephan, Fan, Feng Ru, Wu, Wenzhuo, Costa, Pedro, del Campo, Javier, Lanceros-Mendez, Senentxu, Khanbareh, Hamideh, Wang, Zhong Lin, Pu, Xiong, Pan, Caofeng, Zhang, Renyun, Xu, Jing, Zhao, Xun, Zhou, Yihao, Chen, Guorui, Tat, Trinny, Ock, Il Woo, Chen, Jun, Graham, Sontyana Adonijah, Yu, Jae Su, Huang, Ling-Zhi, Li, Dan-Dan, Ma, Ming-Guo, Luo, Jikui, Jiang, Feng, Lee, Pooi See, Dudem, Bhaskar, Vivekananthan, Venkateswaran, Kanatzidis, Mercouri G, Xie, Hongyao, Shi, Xiao-Lei, Chen, Zhi-Gang, Riss, Alexander, Parzer, Michael, Garmroudi, Fabian, Bauer, Ernst, Zavanelli, Duncan, Brod, Madison K, Al Malki, Muath, Snyder, G Jeffrey, Kovnir, Kirill, Kauzlarich, Susan M, Uher, Ctirad, Lan, Jinle, Lin, Yuan-Hua, Fonseca, Luis, Morata, Alex, Martin-Gonzalez, Marisol, Pennelli, Giovanni, Berthebaud, David, Mori, Takao, Quinn, Robert J, Bos, Jan-Willem G, Candolfi, Christophe, Gougeon, Patrick, Gall, Philippe, Lenoir, Bertrand, Venkateshvaran, Deepak, Kaestner, Bernd, Zhao, Yunshan, Zhang, Gang, Nonoguchi, Yoshiyuki, Schroeder, Bob C, Bilotti, Emiliano, Menon, Akanksha K, Urban, Jeffrey J, Fenwick, Oliver, Asker, Ceyla, and Talin, A Alec

Subjects
Engineering, Materials Engineering, Affordable and Clean Energy, energy harvesting materials, photovoltaics, thermoelectric energy harvesting, piezoelectric energy harvesting, triboelectric energy harvesting, radiofrequency energy harvesting, sustainability, Macromolecular and materials chemistry, Physical chemistry, Materials engineering
Abstract

Ambient energy harvesting has great potential to contribute to sustainable development and address growing environmental challenges. Converting waste energy from energy-intensive processes and systems (e.g. combustion engines and furnaces) is crucial to reducing their environmental impact and achieving net-zero emissions. Compact energy harvesters will also be key to powering the exponentially growing smart devices ecosystem that is part of the Internet of Things, thus enabling futuristic applications that can improve our quality of life (e.g. smart homes, smart cities, smart manufacturing, and smart healthcare). To achieve these goals, innovative materials are needed to efficiently convert ambient energy into electricity through various physical mechanisms, such as the photovoltaic effect, thermoelectricity, piezoelectricity, triboelectricity, and radiofrequency wireless power transfer. By bringing together the perspectives of experts in various types of energy harvesting materials, this Roadmap provides extensive insights into recent advances and present challenges in the field. Additionally, the Roadmap analyses the key performance metrics of these technologies in relation to their ultimate energy conversion limits. Building on these insights, the Roadmap outlines promising directions for future research to fully harness the potential of energy harvesting materials for green energy anytime, anywhere.

Published
2023

32. The James Webb Space Telescope Mission

Author

Gardner, Jonathan P., Mather, John C., Abbott, Randy, Abell, James S., Abernathy, Mark, Abney, Faith E., Abraham, John G., Abraham, Roberto, Abul-Huda, Yasin M., Acton, Scott, Adams, Cynthia K., Adams, Evan, Adler, David S., Adriaensen, Maarten, Aguilar, Jonathan Albert, Ahmed, Mansoor, Ahmed, Nasif S., Ahmed, Tanjira, Albat, Rüdeger, Albert, Loïc, Alberts, Stacey, Aldridge, David, Allen, Mary Marsha, Allen, Shaune S., Altenburg, Martin, Altunc, Serhat, Alvarez, Jose Lorenzo, Álvarez-Márquez, Javier, de Oliveira, Catarina Alves, Ambrose, Leslie L., Anandakrishnan, Satya M., Andersen, Gregory C., Anderson, Harry James, Anderson, Jay, Anderson, Kristen, Anderson, Sara M., Aprea, Julio, Archer, Benita J., Arenberg, Jonathan W., Argyriou, Ioannis, Arribas, Santiago, Artigau, Étienne, Arvai, Amanda Rose, Atcheson, Paul, Atkinson, Charles B., Averbukh, Jesse, Aymergen, Cagatay, Bacinski, John J., Baggett, Wayne E., Bagnasco, Giorgio, Baker, Lynn L., Balzano, Vicki Ann, Banks, Kimberly A., Baran, David A., Barker, Elizabeth A., Barrett, Larry K., Barringer, Bruce O., Barto, Allison, Bast, William, Baudoz, Pierre, Baum, Stefi, Beatty, Thomas G., Beaulieu, Mathilde, Bechtold, Kathryn, Beck, Tracy, Beddard, Megan M., Beichman, Charles, Bellagama, Larry, Bely, Pierre, Berger, Timothy W., Bergeron, Louis E., Darveau-Bernier, Antoine, Bertch, Maria D., Beskow, Charlotte, Betz, Laura E., Biagetti, Carl P., Birkmann, Stephan, Bjorklund, Kurt F., Blackwood, James D., Blazek, Ronald Paul, Blossfeld, Stephen, Bluth, Marcel, Boccaletti, Anthony, Boegner Jr., Martin E., Bohlin, Ralph C., Boia, John Joseph, Böker, Torsten, Bonaventura, N., Bond, Nicholas A., Bosley, Kari Ann, Boucarut, Rene A., Bouchet, Patrice, Bouwman, Jeroen, Bower, Gary, Bowers, Ariel S., Bowers, Charles W., Boyce, Leslye A., Boyer, Christine T., Boyer, Martha L., Boyer, Michael, Boyer, Robert, Bradley, Larry D., Brady, Gregory R., Brandl, Bernhard R., Brannen, Judith L., Breda, David, Bremmer, Harold G., Brennan, David, Bresnahan, Pamela A., Bright, Stacey N., Broiles, Brian J., Bromenschenkel, Asa, Brooks, Brian H., Brooks, Keira J., Brown, Bob, Brown, Bruce, Brown, Thomas M., Bruce, Barry W., Bryson, Jonathan G., Bujanda, Edwin D., Bullock, Blake M., Bunker, A. J., Bureo, Rafael, Burt, Irving J., Bush, James Aaron, Bushouse, Howard A., Bussman, Marie C., Cabaud, Olivier, Cale, Steven, Calhoon, Charles D., Calvani, Humberto, Canipe, Alicia M., Caputo, Francis M., Cara, Mihai, Carey, Larkin, Case, Michael Eli, Cesari, Thaddeus, Cetorelli, Lee D., Chance, Don R., Chandler, Lynn, Chaney, Dave, Chapman, George N., Charlot, S., Chayer, Pierre, Cheezum, Jeffrey I., Chen, Bin, Chen, Christine H., Cherinka, Brian, Chichester, Sarah C., Chilton, Zachary S., Chittiraibalan, Dharini, Clampin, Mark, Clark, Charles R., Clark, Kerry W., Clark, Stephanie M., Claybrooks, Edward E., Cleveland, Keith A., Cohen, Andrew L., Cohen, Lester M., Colón, Knicole D., Coleman, Benee L., Colina, Luis, Comber, Brian J., Comeau, Thomas M., Comer, Thomas, Reis, Alain Conde, Connolly, Dennis C., Conroy, Kyle E., Contos, Adam R., Contreras, James, Cook, Neil J., Cooper, James L., Cooper, Rachel Aviva, Correia, Michael F., Correnti, Matteo, Cossou, Christophe, Costanza, Brian F., Coulais, Alain, Cox, Colin R., Coyle, Ray T., Cracraft, Misty M., Noriega-Crespo, Alberto, Crew, Keith A., Curtis, Gary J., Cusveller, Bianca, Maciel, Cleyciane Da Costa, Dailey, Christopher T., Daugeron, Frédéric, Davidson, Greg S., Davies, James E., Davis, Katherine Anne, Davis, Michael S., Day, Ratna, de Chambure, Daniel, de Jong, Pauline, De Marchi, Guido, Dean, Bruce H., Decker, John E., Delisa, Amy S., Dell, Lawrence C., Dellagatta, Gail, Dembinska, Franciszka, Demosthenes, Sandor, Dencheva, Nadezhda M., Deneu, Philippe, DePriest, William W., Deschenes, Jeremy, Dethienne, Nathalie, Detre, Örs Hunor, Diaz, Rosa Izela, Dicken, Daniel, DiFelice, Audrey S., Dillman, Matthew, Disharoon, Maureen O., van Dishoeck, Ewine F., Dixon, William V., Doggett, Jesse B., Dominguez, Keisha L., Donaldson, Thomas S., Doria-Warner, Cristina M., Santos, Tony Dos, Doty, Heather, Douglas Jr., Robert E., Doyon, René, Dressler, Alan, Driggers, Jennifer, Driggers, Phillip A., Dunn, Jamie L., DuPrie, Kimberly C., Dupuis, Jean, Durning, John, Dutta, Sanghamitra B., Earl, Nicholas M., Eccleston, Paul, Ecobichon, Pascal, Egami, Eiichi, Ehrenwinkler, Ralf, Eisenhamer, Jonathan D., Eisenhower, Michael, Eisenstein, Daniel J., Hamel, Zaky El, Elie, Michelle L., Elliott, James, Elliott, Kyle Wesley, Engesser, Michael, Espinoza, Néstor, Etienne, Odessa, Etxaluze, Mireya, Evans, Leah, Fabreguettes, Luce, Falcolini, Massimo, Falini, Patrick R., Fatig, Curtis, Feeney, Matthew, Feinberg, Lee D., Fels, Raymond, Ferdous, Nazma, Ferguson, Henry C., Ferrarese, Laura, Ferreira, Marie-Héléne, Ferruit, Pierre, Ferry, Malcolm, Filippazzo, Joseph Charles, Firre, Daniel, Fix, Mees, Flagey, Nicolas, Flanagan, Kathryn A., Fleming, Scott W., Florian, Michael, Flynn, James R., Foiadelli, Luca, Fontaine, Mark R., Fontanella, Erin Marie, Forshay, Peter Randolph, Fortner, Elizabeth A., Fox, Ori D., Framarini, Alexandro P., Francisco, John I., Franck, Randy, Franx, Marijn, Franz, David E., Friedman, Scott D., Friend, Katheryn E., Frost, James R., Fu, Henry, Fullerton, Alexander W., Gaillard, Lionel, Galkin, Sergey, Gallagher, Ben, Galyer, Anthony D., Marín, Macarena García, Gardner, Lisa E., Garland, Dennis, Garrett, Bruce Albert, Gasman, Danny, Gáspár, András, Gastaud, René, Gaudreau, Daniel, Gauthier, Peter Timothy, Geers, Vincent, Geithner, Paul H., Gennaro, Mario, Gerber, John, Gereau, John C., Giampaoli, Robert, Giardino, Giovanna, Gibbons, Paul C., Gilbert, Karolina, Gilman, Larry, Girard, Julien H., Giuliano, Mark E., Gkountis, Konstantinos, Glasse, Alistair, Glassmire, Kirk Zachary, Glauser, Adrian Michael, Glazer, Stuart D., Goldberg, Joshua, Golimowski, David A., Gonzaga, Shireen P., Gordon, Karl D., Gordon, Shawn J., Goudfrooij, Paul, Gough, Michael J., Graham, Adrian J., Grau, Christopher M., Green, Joel David, Greene, Gretchen R., Greene, Thomas P., Greenfield, Perry E., Greenhouse, Matthew A., Greve, Thomas R., Greville, Edgar M., Grimaldi, Stefano, Groe, Frank E., Groebner, Andrew, Grumm, David M., Grundy, Timothy, Güdel, Manuel, Guillard, Pierre, Guldalian, John, Gunn, Christopher A., Gurule, Anthony, Gutman, Irvin Meyer, Guy, Paul D., Guyot, Benjamin, Hack, Warren J., Haderlein, Peter, Hagan, James B., Hagedorn, Andria, Hainline, Kevin, Haley, Craig, Hami, Maryam, Hamilton, Forrest Clifford, Hammann, Jeffrey, Hammel, Heidi B., Hanley, Christopher J., Hansen, Carl August, Hardy, Bruce, Harnisch, Bernd, Harr, Michael Hunter, Harris, Pamela, Hart, Jessica Ann, Hartig, George F., Hasan, Hashima, Hashim, Kathleen Marie, Hashimoto, Ryan, Haskins, Sujee J., Hawkins, Robert Edward, Hayden, Brian, Hayden, William L., Healy, Mike, Hecht, Karen, Heeg, Vince J., Hejal, Reem, Helm, Kristopher A., Hengemihle, Nicholas J., Henning, Thomas, Henry, Alaina, Henry, Ronald L., Henshaw, Katherine, Hernandez, Scarlin, Herrington, Donald C., Heske, Astrid, Hesman, Brigette Emily, Hickey, David L., Hilbert, Bryan N., Hines, Dean C., Hinz, Michael R., Hirsch, Michael, Hitcho, Robert S., Hodapp, Klaus, Hodge, Philip E., Hoffman, Melissa, Holfeltz, Sherie T., Holler, Bryan Jason, Hoppa, Jennifer Rose, Horner, Scott, Howard, Joseph M., Howard, Richard J., Huber, Jean M., Hunkeler, Joseph S., Hunter, Alexander, Hunter, David Gavin, Hurd, Spencer W., Hurst, Brendan J., Hutchings, John B., Hylan, Jason E., Ignat, Luminita Ilinca, Illingworth, Garth, Irish, Sandra M., Isaacs III, John C., Jackson Jr., Wallace C., Jaffe, Daniel T., Jahic, Jasmin, Jahromi, Amir, Jakobsen, Peter, James, Bryan, James, John C., James, LeAndrea Rae, Jamieson, William Brian, Jandra, Raymond D., Jayawardhana, Ray, Jedrzejewski, Robert, Jeffers, Basil S., Jensen, Peter, Joanne, Egges, Johns, Alan T., Johnson, Carl A., Johnson, Eric L., Johnson, Patricia, Johnson, Phillip Stephen, Johnson, Thomas K., Johnson, Timothy W., Johnstone, Doug, Jollet, Delphine, Jones, Danny P., Jones, Gregory S., Jones, Olivia C., Jones, Ronald A., Jones, Vicki, Jordan, Ian J., Jordan, Margaret E., Jue, Reginald, Jurkowski, Mark H., Justis, Grant, Justtanont, Kay, Kaleida, Catherine C., Kalirai, Jason S., Kalmanson, Phillip Cabrales, Kaltenegger, Lisa, Kammerer, Jens, Kan, Samuel K., Kanarek, Graham Childs, Kao, Shaw-Hong, Karakla, Diane M., Karl, Hermann, Kassin, Susan A., Kauffman, David D., Kavanagh, Patrick, Kelley, Leigh L., Kelly, Douglas M., Kendrew, Sarah, Kennedy, Herbert V., Kenny, Deborah A., Keski-Kuha, Ritva A., Keyes, Charles D., Khan, Ali, Kidwell, Richard C., Kimble, Randy A., King, James S., King, Richard C., Kinzel, Wayne M., Kirk, Jeffrey R., Kirkpatrick, Marc E., Klaassen, Pamela, Klingemann, Lana, Klintworth, Paul U., Knapp, Bryan Adam, Knight, Scott, Knollenberg, Perry J., Knutsen, Daniel Mark, Koehler, Robert, Koekemoer, Anton M., Kofler, Earl T., Kontson, Vicki L., Kovacs, Aiden Rose, Kozhurina-Platais, Vera, Krause, Oliver, Kriss, Gerard A., Krist, John, Kristoffersen, Monica R., Krogel, Claudia, Krueger, Anthony P., Kulp, Bernard A., Kumari, Nimisha, Kwan, Sandy W., Kyprianou, Mark, Labador, Aurora Gadiano, Labiano, Álvaro, Lafrenière, David, Lagage, Pierre-Olivier, Laidler, Victoria G., Laine, Benoit, Laird, Simon, Lajoie, Charles-Philippe, Lallo, Matthew D., Lam, May Yen, LaMassa, Stephanie Marie, Lambros, Scott D., Lampenfield, Richard Joseph, Lander, Matthew Ed, Langston, James Hutton, Larson, Kirsten, Larson, Melora, LaVerghetta, Robert Joseph, Law, David R., Lawrence, Jon F., Lee, David W., Lee, Janice, Lee, Yat-Ning Paul, Leisenring, Jarron, Leveille, Michael Dunlap, Levenson, Nancy A., Levi, Joshua S., Levine, Marie B., Lewis, Dan, Lewis, Jake, Lewis, Nikole, Libralato, Mattia, Lidon, Norbert, Liebrecht, Paula Louisa, Lightsey, Paul, Lilly, Simon, Lim, Frederick C., Lim, Pey Lian, Ling, Sai-Kwong, Link, Lisa J., Link, Miranda Nicole, Lipinski, Jamie L., Liu, XiaoLi, Lo, Amy S., Lobmeyer, Lynette, Logue, Ryan M., Long, Chris A., Long, Douglas R., Long, Ilana D., Long, Knox S., López-Caniego, Marcos, Lotz, Jennifer M., Love-Pruitt, Jennifer M., Lubskiy, Michael, Luers, Edward B., Luetgens, Robert A., Luevano, Annetta J., Lui, Sarah Marie G. Flores, Lund III, James M., Lundquist, Ray A., Lunine, Jonathan, Lützgendorf, Nora, Lynch, Richard J., MacDonald, Alex J., MacDonald, Kenneth, Macias, Matthew J., Macklis, Keith I., Maghami, Peiman, Maharaja, Rishabh Y., Maiolino, Roberto, Makrygiannis, Konstantinos G., Malla, Sunita Giri, Malumuth, Eliot M., Manjavacas, Elena, Marini, Andrea, Marrione, Amanda, Marston, Anthony, Martel, André R, Martin, Didier, Martin, Peter G., Martinez, Kristin L., Maschmann, Marc, Masci, Gregory L., Masetti, Margaret E., Maszkiewicz, Michael, Matthews, Gary, Matuskey, Jacob E., McBrayer, Glen A., McCarthy, Donald W., McCaughrean, Mark J., McClare, Leslie A., McClare, Michael D., McCloskey, John C., McClurg, Taylore D., McCoy, Martin, McElwain, Michael W., McGregor, Roy D., McGuffey, Douglas B., McKay, Andrew G., McKenzie, William K., McLean, Brian, McMaster, Matthew, McNeil, Warren, De Meester, Wim, Mehalick, Kimberly L., Meixner, Margaret, Meléndez, Marcio, Menzel, Michael P., Menzel, Michael T., Merz, Matthew, Mesterharm, David D., Meyer, Michael R., Meyett, Michele L., Meza, Luis E., Midwinter, Calvin, Milam, Stefanie N., Miller, Jay Todd, Miller, William C., Miskey, Cherie L., Misselt, Karl, Mitchell, Eileen P., Mohan, Martin, Montoya, Emily E., Moran, Michael J., Morishita, Takahiro, Moro-Martín, Amaya, Morrison, Debra L., Morrison, Jane, Morse, Ernie C., Moschos, Michael, Moseley, S. H., Mosier, Gary E., Mosner, Peter, Mountain, Matt, Muckenthaler, Jason S., Mueller, Donald G., Mueller, Migo, Muhiem, Daniella, Mühlmann, Prisca, Mullally, Susan Elizabeth, Mullen, Stephanie M., Munger, Alan J, Murphy, Jess, Murray, Katherine T., Muzerolle, James C., Mycroft, Matthew, Myers, Andrew, Myers, Carey R., Myers, Fred Richard R., Myers, Richard, Myrick, Kaila, Nagle IV, Adrian F., Nayak, Omnarayani, Naylor, Bret, Neff, Susan G., Nelan, Edmund P., Nella, John, Nguyen, Duy Tuong, Nguyen, Michael N., Nickson, Bryony, Nidhiry, John Joseph, Niedner, Malcolm B., Nieto-Santisteban, Maria, Nikolov, Nikolay K., Nishisaka, Mary Ann, Nota, Antonella, O'Mara, Robyn C., Oboryshko, Michael, O'Brien, Marcus B., Ochs, William R., Offenberg, Joel D., Ogle, Patrick Michael, Ohl, Raymond G., Olmsted, Joseph Hamden, Osborne, Shannon Barbara, O'Shaughnessy, Brian Patrick, Östlin, Göran, O'Sullivan, Brian, Otor, O. Justin, Ottens, Richard, Ouellette, Nathalie N. -Q., Outlaw, Daria J., Owens, Beverly A., Pacifici, Camilla, Page, James Christophe, Paranilam, James G., Park, Sang, Parrish, Keith A., Paschal, Laura, Patapis, Polychronis, Patel, Jignasha, Patrick, Keith, Pattishall Jr., Robert A., Paul, Douglas William, Paul, Shirley J., Pauly, Tyler Andrew, Pavlovsky, Cheryl M., Peña-Guerrero, Maria, Pedder, Andrew H., Peek, Matthew Weldon, Pelham, Patricia A., Penanen, Konstantin, Perriello, Beth A., Perrin, Marshall D., Perrine, Richard F., Perrygo, Chuck, Peslier, Muriel, Petach, Michael, Peterson, Karla A., Pfarr, Tom, Pierson, James M., Pietraszkiewicz, Martin, Pilchen, Guy, Pipher, Judy L., Pirzkal, Norbert, Pitman, Joseph T., Player, Danielle M., Plesha, Rachel, Plitzke, Anja, Pohner, John A., Poletis, Karyn Konstantin, Pollizzi, Joseph A., Polster, Ethan, Pontius, James T., Pontoppidan, Klaus, Porges, Susana C., Potter, Gregg D., Prescott, Stephen, Proffitt, Charles R., Pueyo, Laurent, Neira, Irma Aracely Quispe, Radich, Armando, Rager, Reiko T., Rameau, Julien, Ramey, Deborah D., Alarcon, Rafael Ramos, Rampini, Riccardo, Rapp, Robert, Rashford, Robert A., Rauscher, Bernard J., Ravindranath, Swara, Rawle, Timothy, Rawlings, Tynika N., Ray, Tom, Regan, Michael W., Rehm, Brian, Rehm, Kenneth D., Reid, Neill, Reis, Carl A., Renk, Florian, Reoch, Tom B., Ressler, Michael, Rest, Armin W., Reynolds, Paul J., Richon, Joel G., Richon, Karen V., Ridgaway, Michael, Riedel, Adric Richard, Rieke, George H., Rieke, Marcia, Rifelli, Richard E., Rigby, Jane R., Riggs, Catherine S., Ringel, Nancy J., Ritchie, Christine E., Rix, Hans-Walter, Robberto, Massimo, Robinson, Michael S., Robinson, Orion, Rock, Frank W., Rodriguez, David R., del Pino, Bruno Rodríguez, Roellig, Thomas, Rohrbach, Scott O., Roman, Anthony J., Romelfanger, Frederick J., Romo Jr., Felipe P., Rosales, Jose J., Rose, Perry, Roteliuk, Anthony F., Roth, Marc N., Rothwell, Braden Quinn, Rouzaud, Sylvain, Rowe, Jason, Rowlands, Neil, Roy, Arpita, Royer, Pierre, Rui, Chunlei, Rumler, Peter, Rumpl, William, Russ, Melissa L., Ryan, Michael B., Ryan, Richard M., Saad, Karl, Sabata, Modhumita, Sabatino, Rick, Sabbi, Elena, Sabelhaus, Phillip A., Sabia, Stephen, Sahu, Kailash C., Saif, Babak N., Salvignol, Jean-Christophe, Samara-Ratna, Piyal, Samuelson, Bridget S., Sanders, Felicia A., Sappington, Bradley, Sargent, B. A., Sauer, Arne, Savadkin, Bruce J., Sawicki, Marcin, Schappell, Tina M., Scheffer, Caroline, Scheithauer, Silvia, Scherer, Ron, Schiff, Conrad, Schlawin, Everett, Schmeitzky, Olivier, Schmitz, Tyler S., Schmude, Donald J., Schneider, Analyn, Schreiber, Jürgen, Schroeven-Deceuninck, Hilde, Schultz, John J., Schwab, Ryan, Schwartz, Curtis H., Scoccimarro, Dario, Scott, John F., Scott, Michelle B., Seaton, Bonita L., Seely, Bruce S., Seery, Bernard, Seidleck, Mark, Sembach, Kenneth, Shanahan, Clare Elizabeth, Shaughnessy, Bryan, Shaw, Richard A., Shay, Christopher Michael, Sheehan, Even, Sheth, Kartik, Shih, Hsin-Yi, Shivaei, Irene, Siegel, Noah, Sienkiewicz, Matthew G., Simmons, Debra D., Simon, Bernard P., Sirianni, Marco, Sivaramakrishnan, Anand, Slade, Jeffrey E., Sloan, G. C., Slocum, Christine E., Slowinski, Steven E., Smith, Corbett T., Smith, Eric P., Smith, Erin C., Smith, Koby, Smith, Robert, Smith, Stephanie J., Smolik, John L., Soderblom, David R., Sohn, Sangmo Tony, Sokol, Jeff, Sonneborn, George, Sontag, Christopher D., Sooy, Peter R., Soummer, Remi, Southwood, Dana M., Spain, Kay, Sparmo, Joseph, Speer, David T., Spencer, Richard, Sprofera, Joseph D., Stallcup, Scott S., Stanley, Marcia K., Stansberry, John A., Stark, Christopher C., Starr, Carl W., Stassi, Diane Y., Steck, Jane A., Steeley, Christine D., Stephens, Matthew A., Stephenson, Ralph J., Stewart, Alphonso C., Stiavelli, Massimo, Stockman Jr., Hervey, Strada, Paolo, Straughn, Amber N., Streetman, Scott, Strickland, David Kendal, Strobele, Jingping F., Stuhlinger, Martin, Stys, Jeffrey Edward, Such, Miguel, Sukhatme, Kalyani, Sullivan, Joseph F., Sullivan, Pamela C., Sumner, Sandra M., Sun, Fengwu, Sunnquist, Benjamin Dale, Swade, Daryl Allen, Swam, Michael S., Swenton, Diane F., Swoish, Robby A., Litten, Oi In Tam, Tamas, Laszlo, Tao, Andrew, Taylor, David K., Taylor, Joanna M., Plate, Maurice te, Van Tea, Mason, Teague, Kelly K., Telfer, Randal C., Temim, Tea, Texter, Scott C., Thatte, Deepashri G., Thompson, Christopher Lee, Thompson, Linda M., Thomson, Shaun R., Thronson, Harley, Tierney, C. M., Tikkanen, Tuomo, Tinnin, Lee, Tippet, William Thomas, Todd, Connor William, Tran, Hien D., Trauger, John, Trejo, Edwin Gregorio, Truong, Justin Hoang Vinh, Tsukamoto, Christine L., Tufail, Yasir, Tumlinson, Jason, Tustain, Samuel, Tyra, Harrison, Ubeda, Leonardo, Underwood, Kelli, Uzzo, Michael A., Vaclavik, Steven, Valenduc, Frida, Valenti, Jeff A., Van Campen, Julie, van de Wetering, Inge, Van Der Marel, Roeland P., van Haarlem, Remy, Vandenbussche, Bart, Vanterpool, Dona D., Vernoy, Michael R., Costas, Maria Begoña Vila, Volk, Kevin, Voorzaat, Piet, Voyton, Mark F., Vydra, Ekaterina, Waddy, Darryl J., Waelkens, Christoffel, Wahlgren, Glenn Michael, Walker Jr., Frederick E., Wander, Michel, Warfield, Christine K., Warner, Gerald, Wasiak, Francis C., Wasiak, Matthew F., Wehner, James, Weiler, Kevin R., Weilert, Mark, Weiss, Stanley B., Wells, Martyn, Welty, Alan D., Wheate, Lauren, Wheeler, Thomas P., White, Christy L., Whitehouse, Paul, Whiteleather, Jennifer Margaret, Whitman, William Russell, Williams, Christina C., Willmer, Christopher N. A., Willott, Chris J., Willoughby, Scott P., Wilson, Andrew, Wilson, Debra, Wilson, Donna V., Windhorst, Rogier, Wislowski, Emily Christine, Wolfe, David J., Wolfe, Michael A., Wolff, Schuyler, Wondel, Amancio, Woo, Cindy, Woods, Robert T., Worden, Elaine, Workman, William, Wright, Gillian S., Wu, Carl, Wu, Chi-Rai, Wun, Dakin D., Wymer, Kristen B., Yadetie, Thomas, Yan, Isabelle C., Yang, Keith C., Yates, Kayla L., Yeager, Christopher R., Yerger, Ethan John, Young, Erick T., Young, Gary, Yu, Gene, Yu, Susan, Zak, Dean S., Zeidler, Peter, Zepp, Robert, Zhou, Julia, Zincke, Christian A., Zonak, Stephanie, and Zondag, Elisabeth

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

Twenty-six years ago a small committee report, building on earlier studies, expounded a compelling and poetic vision for the future of astronomy, calling for an infrared-optimized space telescope with an aperture of at least $4m$. With the support of their governments in the US, Europe, and Canada, 20,000 people realized that vision as the $6.5m$ James Webb Space Telescope. A generation of astronomers will celebrate their accomplishments for the life of the mission, potentially as long as 20 years, and beyond. This report and the scientific discoveries that follow are extended thank-you notes to the 20,000 team members. The telescope is working perfectly, with much better image quality than expected. In this and accompanying papers, we give a brief history, describe the observatory, outline its objectives and current observing program, and discuss the inventions and people who made it possible. We cite detailed reports on the design and the measured performance on orbit., Comment: Accepted by PASP for the special issue on The James Webb Space Telescope Overview, 29 pages, 4 figures

Published
2023
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33. Timing the r-Process Enrichment of the Ultra-Faint Dwarf Galaxy Reticulum II

Author

Simon, Joshua D., Brown, Thomas M., Mutlu-Pakdil, Burçin, Ji, Alexander P., Drlica-Wagner, Alex, Avila, Roberto J., Martínez-Vázquez, Clara E., Li, Ting S., Balbinot, Eduardo, Bechtol, Keith, Frebel, Anna, Geha, Marla, Hansen, Terese T., James, David J., Pace, Andrew B., Aguena, M., Alves, O., Andrade-Oliveira, F., Annis, J., Bacon, D., Bertin, E., Brooks, D., Burke, D. L., Rosell, A. Carnero, Kind, M. Carrasco, Carretero, J., Costanzi, M., da Costa, L. N., De Vicente, J., Desai, S., Doel, P., Everett, S., Ferrero, I., Frieman, J., García-Bellido, J., Gatti, M., Gerdes, D. W., Gruen, D., Gruendl, R. A., Gschwend, J., Gutierrez, G., Hinton, S. R., Hollowood, D. L., Honscheid, K., Kuehn, K., Kuropatkin, N., Marshall, J. L., Mena-Fernández, J., Miquel, R., Palmese, A., Paz-Chinchón, F., Pereira, M. E. S., Pieres, A., Malagón, A. A. Plazas, Raveri, M., Rodriguez-Monroy, M., Sanchez, E., Santiago, B., Scarpine, V., Sevilla-Noarbe, I., Smith, M., Suchyta, E., Swanson, M. E. C., Tarle, G., To, C., Vincenzi, M., Weaverdyck, N., and Wilkinson, R. D.

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

The ultra-faint dwarf galaxy Reticulum II (Ret II) exhibits a unique chemical evolution history, with 72 +10/-12% of its stars strongly enhanced in r-process elements. We present deep Hubble Space Telescope photometry of Ret II and analyze its star formation history. As in other ultra-faint dwarfs, the color-magnitude diagram is best fit by a model consisting of two bursts of star formation. If we assume that the bursts were instantaneous, then the older burst occurred around the epoch of reionization and formed ~80% of the stars in the galaxy, while the remainder of the stars formed ~3 Gyr later. When the bursts are allowed to have nonzero durations we obtain slightly better fits. The best-fitting model in this case consists of two bursts beginning before reionization, with approximately half the stars formed in a short (100 Myr) burst and the other half in a more extended period lasting 2.6 Gyr. Considering the full set of viable star formation history models, we find that 28% of the stars formed within 500 +/- 200 Myr of the onset of star formation. The combination of the star formation history and the prevalence of r-process-enhanced stars demonstrates that the r-process elements in Ret II must have been synthesized early in its initial star-forming phase. We therefore constrain the delay time between the formation of the first stars in Ret II and the r-process nucleosynthesis to be less than 500 Myr. This measurement rules out an r-process source with a delay time of several Gyr or more such as GW170817., Comment: 14 pages, 5 figures, 1 table. Accepted for publication in ApJ

Published
2022
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35. Using fluorescent beads to emulate single flurophores

Author

Aleman-Castaneda, Luis A., Feng, Sherry Yi-Ting, Gutierrez-Cuevas, Rodrigo, Herrera, Isael, Brown, Thomas G., Brasselet, Sophie, and Alonso, Miguel A.

Subjects
Physics - Optics, Physics - Biological Physics
Abstract

In this work, we study the conditions under which fluorescent beads can be used to emulate single fluorescent molecules in the calibration of optical microscopes. Although beads are widely used due to their brightness and easy manipulation, there can be notable differences between the point spread functions (PSFs) they produce and those for single-molecule fluorophores, caused by their different emission pattern and their size. We study theoretically these differences for various scenarios, e.g. with or without polarization channel splitting, to determine the conditions under which the use of beads as a model for single molecules is valid. We also propose methods to model the blurring due to the size difference and compensate for it to produce PSFs that are more similar to those for single molecules.

Published
2022
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40. An Isolated Stellar-Mass Black Hole Detected Through Astrometric Microlensing

Author

Sahu, Kailash C., Anderson, Jay, Casertano, Stefano, Bond, Howard E., Udalski, Andrzej, Dominik, Martin, Calamida, Annalisa, Bellini, Andrea, Brown, Thomas M., Rejkuba, Marina, Bajaj, Varun, Kains, Noe, Ferguson, Henry C., Fryer, Chris L., Yock, Philip, Mroz, Przemek, Kozlowski, Szymon, Pietrukowicz, Pawel, Poleski, Radek, Skowron, Jan, Soszynski, Igor, Szymanski, Michael K., Ulaczyk, Krzysztof, Wyrzykowski, Lukasz, Barry, Richard, Bennett, David P., Bond, Ian A., Hirao, Yuki, Silva, Stela Ishitani, Kondo, Iona, Koshimoto, Naoki, Ranc, Clement, Rattenbury, Nicholas J., Sumi, Takahiro, Suzuki, Daisuke, Tristram, Paul J., Vandorou, Aikaterini, Beaulieu, Jean-Philippe, Marquette, Jean-Baptiste, Cole, Andrew, Fouque, Pascal, Hill, Kym, Dieters, Stefan, Coutures, Christian, Dominis-Prester, Dijana, Bennett, Clara, Bachelet, Etienne, Menzies, John, Alb-row, Michael, Pollard, Karen, Gould, Andrew, Yee, Jennifer, Allen, William, de Almeida, Leonardo Andrade, Christie, Grant, Drummond, John, Gal-Yam, Avishay, Gorbikov, Evgeny, Jablonski, Francisco, Lee, Chung-Uk, Maoz, Dan, Manulis, Ilan, McCormick, Jennie, Natusch, Tim, Pogge, Richard W., Shvartzvald, Yossi, Jorgensen, Uffe G., Alsubai, Khalid A., Andersen, Michael I., Bozza, Valerio, Novati, Sebastiano Calchi, Burgdorf, Martin, Hinse, Tobias C., Hundertmark, Markus, Husser, Tim-Oliver, Kerins, Eamonn, Longa-Pena, Penelope, Mancini, Luigi, Penny, Matthew, Rahvar, Sohrab, Ricci, Davide, Sajadian, Sedighe, Skottfelt, Jesper, Snodgrass, Colin, Southworth, John, Tregloan-Reed, Jeremy, Wambsganss, Joachim, Wertz, Olivier, Tsapras, Yiannis, Street, Rachel A., Bramich, Daniel M., Horne, Keith, and Steele, Iain A.

Subjects
Astrophysics - Solar and Stellar Astrophysics, Astrophysics - Astrophysics of Galaxies, Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report the first unambiguous detection and mass measurement of an isolated stellar-mass black hole (BH). We used the Hubble Space Telescope (HST) to carry out precise astrometry of the source star of the long-duration (t_E~270 days), high-magnification microlensing event MOA-2011-BLG-191/OGLE-2011-BLG-0462 (hereafter designated as MOA-11-191/OGLE-11-462), in the direction of the Galactic bulge. HST imaging, conducted at eight epochs over an interval of six years, reveals a clear relativistic astrometric deflection of the background star's apparent position. Ground-based photometry of MOA-11-191/OGLE-11-462 shows a parallactic signature of the effect of the Earth's motion on the microlensing light curve. Combining the HST astrometry with the ground-based light curve and the derived parallax, we obtain a lens mass of 7.1 +/- 1.3 Msun and a distance of 1.58 +/- 0.18 kpc. We show that the lens emits no detectable light, which, along with having a mass higher than is possible for a white dwarf or neutron star, confirms its BH nature. Our analysis also provides an absolute proper motion for the BH. The proper motion is offset from the mean motion of Galactic-disk stars at similar distances by an amount corresponding to a transverse space velocity of ~45 km/s, suggesting that the BH received a 'natal kick' from its supernova explosion. Previous mass determinations for stellar-mass BHs have come from radial-velocity measurements of Galactic X-ray binaries, and from gravitational radiation emitted by merging BHs in binary systems in external galaxies. Our mass measurement is the first for an isolated stellar-mass BH using any technique., Comment: 37 pages, Published in ApJ

Published
2022
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42. Relative Ages of Nine Inner Milky Way Globular Clusters from Proper Motion Cleaned Color-Magnitude Diagrams

Author

Cohen, Roger E., Bellini, Andrea, Casagrande, Luca, Brown, Thomas M., Correnti, Matteo, and Kalirai, Jason S.

Subjects
Astrophysics - Astrophysics of Galaxies, Astrophysics - Solar and Stellar Astrophysics
Abstract

Our picture of the age-metallicity relation for Milky Way globular clusters (MWGCs) is still highly incomplete, and the majority of MWGCs lack self-consistent age measurements. Here, we exploit deep, homogenous multi-epoch Hubble Space Telescope (HST) imaging of nine MWGCs located towards the inner Milky Way to measure their relative ages, in most cases for the first time. Our relative age measurements are designed to be directly comparable to the large set of MWGC ages presented by VandenBerg et al. (2013, V13), using identical filters, evolutionary models, and bolometric corrections, extended to the higher extinction values relevant to our target clusters. Adopting the V13 MWGC age scale, our relative age measurements imply that our target clusters are consistently very old, with a mean age of 12.9$\pm$0.4 Gyr, with the exception of the young metal-rich MWGC NGC 6342. We perform two tests to validate the precision of our methodology, and discuss the implications of our target cluster loci in the MWGC age-metallicity plane. In addition, we use our fully self-consistent bolometric corrections to assess the systematic impact of variations in the total-to-selective extinction ratio $R_{V}$ on relative age measurements., Comment: AJ Accepted. 15 pages, 5 figures, 3 tables

Published
2021
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43. Star Formation Histories of Ultra-Faint Dwarf Galaxies: environmental differences between Magellanic and non-Magellanic satellites?

Author

Sacchi, Elena, Richstein, Hannah, Kallivayalil, Nitya, van der Marel, Roeland, Libralato, Mattia, Zivick, Paul, Besla, Gurtina, Brown, Thomas M., Choi, Yumi, Deason, Alis, Fritz, Tobias, Geha, Marla, Guhathakurta, Puragra, Jeon, Myoungwon, Kirby, Evan, Majewski, Steven R., Patel, Ekta, Simon, Joshua D., Sohn, Sangmo Tony, Tollerud, Erik, and Wetzel, Andrew

Subjects
Astrophysics - Astrophysics of Galaxies
Abstract

We present the color-magnitude diagrams and star formation histories (SFHs) of seven ultra-faint dwarf galaxies: Horologium 1, Hydra 2, Phoenix 2, Reticulum 2, Sagittarius 2, Triangulum 2, and Tucana 2, derived from high-precision Hubble Space Telescope photometry. We find that the SFH of each galaxy is consistent with them having created at least 80% of the stellar mass by $z\sim6$. For all galaxies, we find quenching times older than 11.5 Gyr ago, compatible with the scenario in which reionization suppresses the star formation of small dark matter halos. However, our analysis also reveals some differences in the SFHs of candidate Magellanic Cloud satellites, i.e., galaxies that are likely satellites of the Large Magellanic Cloud and that entered the Milky Way potential only recently. Indeed, Magellanic satellites show quenching times about 600 Myr more recent with respect to those of other Milky Way satellites, on average, even though the respective timings are still compatible within the errors. This finding is consistent with theoretical models that suggest that satellites' SFHs may depend on their host environment at early times, although we caution that within the error bars all galaxies in our sample are consistent with being quenched at a single epoch., Comment: 7 pages, 3 figures, 2 tables. Accepted for publication in ApJL

Published
2021
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48. High-temperature dielectrics based on tungsten bronze structured niobate ceramics

Author

Brown, Thomas Anthony, Milne, Steven, and Brown, Andy

Abstract

A novel high temperature dielectric ceramic has been demonstrated based on strontium sodium niobate, Sr2NaNb5O15 (SNN1.0), which has the tungsten bronze crystal structure and shows relaxor-like weak frequency dispersion. Initial experiments involved co-doping with low levels of, Ca2+, Y3+ and Zr4+ to introduce chemical inhomogeneity to broaden the twin dielectric peaks (Curie peak at 305 ᵒC, and a low temperature peak at -15 ᵒC in SNN1.0). The resulting materials were observed to exhibit high and stable relative permittivity across the technologically important -55 to 300 ᵒC temperature range, with the aim of restricting the variation in permittivity to within the Electronics Industries Alliance R-type ±15 % value. Unlike previously reported materials with similar dielectric properties, the new dielectrics do not contain Bi or Pb. In principle this makes them compatible with base metal electrode multilayer ceramic manufacturing processing. For tri-doped compositions, Sr2-x-yCaxYxNaNb5-yZryO15 (SCNN-YZ) dielectric peaks became very diffuse. At x = y = 0.05, median εr values were 1310 +/-10 % from -65 to 300 °C, with dielectric loss tangents, tan δ, ≤ 0.035 from -34 to 378 °C. Microstructural analyses excluded core-shell mechanisms being responsible for the flattening of the εr -T response. A further series of experiments with individual dopants were performed to examine the reasons for peak suppression and attainment of Rtype stability in relative permittivity. It was also realised that SNN was a solid solution Sr2+xNa1-2xNb5O15 (SNN). On cooling from sintering temperatures the SNN1.0 composition, x = 0, lies outside the single phase solid solution region at room temperature and exists as a two phase mixture of the limiting solid solution composition, (x ~ 0.9), and a Sr modified NaNbO3 phase. Sodium deficient variants of SNN (Sr2.1Na0.8Nb5O15, SNN0.8) were therefore investigated to produce a single phase composition. Nevertheless, because the early tri-doped results were based on x = 0 (Sr2NaNb5O15) it was decided to continue to use this as a starting point from which to examine the effects of single-dopants. The single doping experiments indicated that A-site vacancies bring about a severe suppression of the Curie peak. However the presence of all three dopants is required to produce the near flat response which was observed for SCNN-YZ (x = y = 0.05). iv Although the dielectric properties of the SCNN-YZ ceramics appear favourable in terms of developing new high temperature capacitor materials, the presence of Na vacancies in the SNN solid compositions is a drawback. A greater problem was discovered in the latter months of the project. It had been reported in the literature that SNN was metastable below ~1200 °C. The significance of this for a capacitor application would depend on the kinetics of decomposition at capacitor operating temperature. Annealing experiments at 300 to 600 °C were initiated. At 600 °C after only 2 to 3 hours additional phases of SrNb2O6 and Sr2Nb10O27 form from the SNN1.0, indicating partial decomposition. At 400 °C there is evidence of decomposition in SNN0.8 after 24 weeks. Even at 300 °C, the upper working temperature of capacitors for some power electronics applications, there is tentative evidence of structural changes.

Published
2022

49. Measuring and understanding senescence in a wild population

Author

Brown, Thomas

Abstract

Senescence - the decline in organismal function and performance - frequently occurs in many taxa. However, within- and between- populations of the same species there can be considerable variation in the onset and rate of senescence. Understanding the causes and fitness consequences of differential senescence is a key objective in the study of life-history evolution and gerontology. Wild populations are uniquely suited for exploring the role of complex genetic, environmental and social contributions to senescence patterns. However, accurately measuring the severity of senescence at the individual-level has presented a long-standing challenge. In this thesis, I explore the utility of several candidate intrinsic markers of senescence in a closely monitored wild population of Seychelles warblers (Acrocephalus sechellensis). Firstly, I reveal complex relationships between haematocrit, age a survival, which suggest haematocrit could be used as a marker of early-life stress. Secondly, I show that telomere dynamics (i.e. the increase and decrease in telomere length within-individuals) reflect life-history costs in females, such as reproductive effort and malarial infections, and subsequently impacts future mortality risk. Thirdly, I find evidence of a silver-spoon effect, whereby individuals in better condition (mass adjusted size) as juveniles have higher survival probabilities throughout adult-life but does not affect patterns of survival- or reproductive senescence. Lastly, I develop a ribosomal DNA-methylation clock for predicting age and survival, with substantially improved accuracy over previously used markers; telomere length and condition. With the combined use of multiple intrinsic markers, this study reveals the dynamic and varied ways in which fitness-related traits change with age in a single species. Based on these findings, I discuss the relative strengths and weaknesses of different intrinsic markers for improving our understanding of ageing, senescence and life-history in wild populations.

Published
2022

50. Uncountably many quasi-isometry classes of groups of type FP via graphical small cancellation theory

Author

Brown, Thomas and Leary, Ian

Abstract

This thesis presents a construction of a new class of groups that are type FP but are not finitely presentable. This is the first such construction that does not rely on Morse theory on cubical complexes and so reinforces the rift between the algebraic property and its geometric counterpart. The central tool used here is small cancellation theory which allows us a comparatively simple way to prove the above claim and also allows access to further results regarding these groups.

Published
2022

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