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3,186 results on '"Lam J"'

1. Resilience to Stress and Adversity: A Narrative Review of the Role of Positive Affect

Author

Egan LA, Park HRP, Lam J, and Gatt JM

Subjects
positive emotion, wellbeing, happiness, stress, trauma, adversity, Psychology, BF1-990, Industrial psychology, HF5548.7-5548.85
Abstract

Luke A Egan,1 Haeme RP Park,1,2,* Janine Lam,1,* Justine M Gatt1– 3 1Centre for Wellbeing, Resilience and Recovery, Neuroscience Research Australia, Randwick, NSW, Australia; 2School of Psychology, University of New South Wales, Kensington, NSW, Australia; 3Black Dog Institute, Randwick, NSW, Australia*These authors contributed equally to this workCorrespondence: Justine M Gatt, Email j.gatt@unsw.edu.auAbstract: The modern conception of mental health encompasses not only mental illness but also mental wellbeing, including positive emotional states and other forms of positive experience. Accordingly, research on resilience — that is, recovery or adaptation following adversity – has recently expanded to consider the roles of positive affect in the resilience process. To review this research, we performed a keyword search of all peer-reviewed journals within the American Psychological Association’s PsycInfo database, retrieving all studies of positive affect in the context of resilience. These studies measured positive affect either as the outcome of the resilience process or as a resilience resource in its own right. With positive affect as the outcome, the literature suggests that various resilience resources can promote positive affect following a stressor, especially positive personality traits (eg, hope, optimism, self-compassion) and supportive interpersonal connections. With positive affect as a resilience resource, the literature suggests that higher levels of positive affect may protect individuals from the impact of stress on a number of outcomes, such as depression and trauma symptoms. In all, the reviewed research showcases a wide range of stressors, resources, and outcomes, and there are numerous openings for future discoveries in this promising area of inquiry.Keywords: positive emotion, wellbeing, happiness, stress, trauma, adversity

Published
2024

2. Ocular surface disease in posttrabeculectomy/mitomycin C patients

Author

Lam J, Wong TT, and Tong L

Subjects
Ophthalmology, RE1-994
Abstract

Janice Lam,1,2 Tina T Wong,1–4 Louis Tong1–3,5 1Singapore National Eye Centre, Singapore; 2Singapore Eye Research Institute, Singapore; 3Department of Ophthalmology, Yong Loo Lin School of Medicine, National University of Singapore, Singapore; 4School of Materials Science and Engineering, Nanyang Technological University, Singapore; 5Office of Clinical Sciences, Duke–National University of Singapore Graduate Medical School, Singapore Background: Our aim was to describe the demographics, risk factors, clinical signs, severity, and outcome of ocular surface disease (OSD) in 12 patients who had undergone trabeculectomy augmented with mitomycin C (MMC).Methods: Twelve glaucoma patients were referred to the Dry Eye Clinic (Singapore National Eye Centre) for further management of clinically significant OSD.Results: Of the 15 eyes from 12 patients, 14 were treated with MMC and one with 5-fluorouracil. Mean age was 69.3±10.6 years and two-thirds were male. The median interval before onset of dry eye symptoms after surgery was 13.5 months. Mean tear breakup time (TBUT) was 5.32 seconds and mean Schirmer score was 6.14 mm/5 min. Possible major risk factors for OSD in the cases include limbal stem cell deficiency occurring from exposure to antimetabolites, chronic use of antiglaucoma medications prior to surgery, and the preoperative status of the ocular surface prior to disease onset. Treatment of OSD resulted in improved best corrected visual acuity (BCVA) in 50% of the patients, with a median gain of two-line improvement in BCVA.Conclusion: OSD is a clinical problem often overlooked in patients who undergo antimetabolite-augmented filtration surgery. Recognition of the condition and appropriate treatment can improve patient symptoms and reduce health-care burdens on the economy. Keywords: cornea, glaucoma, ocular surface, trabeculectomy

Published
2015

3. Serviceability Assessment of FRP-Reinforced Concrete Beams Using Parametrized Tensile Stress Block

Author

Ng, P. L., Kaklauskas, G., Lam, J. Y. K., di Prisco, Marco, Series Editor, Chen, Sheng-Hong, Series Editor, Vayas, Ioannis, Series Editor, Kumar Shukla, Sanjay, Series Editor, Sharma, Anuj, Series Editor, Kumar, Nagesh, Series Editor, Wang, Chien Ming, Series Editor, Cui, Zhen-Dong, Series Editor, Barros, Joaquim A. O., editor, Kaklauskas, Gintaris, editor, and Zavadskas, Edmundas K., editor

Published
2024
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4. The effects of shared situational awareness on functional and hospital outcomes of hospitalized older adults with heart failure

Author

Lee JH, Kim SJ, Lam J, Kim S, Nakagawa S, and Yoo JW

Subjects
Medicine (General), R5-920
Abstract

Joo H Lee,1 Sun J Kim,2,3 Julia Lam,4 Sulgi Kim,5 Shunichi Nakagawa,6 Ji W Yoo7,8 1Department of Media and Communication, Hanyang University College of Social Sciences, Seoul, Korea; 2Department of Public Health, 3Institute of Health Services Research, Yonsei University College of Medicine, Seoul, Korea; 4University of Wisconsin School of Medicine and Public Health, Madison, WI, USA; 5Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, USA; 6Department of Medicine, Columbia University College of Physicians and Surgeons, New York, NY, USA; 7Center for Senior Health and Longevity, Aurora Health Care, 8Department of Medicine, University of Wisconsin School of Medicine and Public Health, Milwaukee, WI, USA Background: Functional decline of hospitalized older adults is common and triggers health care expenditures. Physical therapy can retard the functional decline that occurs during hospitalization. This study aims to examine whether shared situational awareness (SSA) intervention may enhance the benefits of physical therapy for hospitalized older persons with a common diagnosis, heart failure. Method: An SSA intervention that involved daily multidisciplinary meetings was applied to the care of functionally declining older adults admitted to the medicine floor for heart failure. Covariates were matched between the intervention group (n=473) and control group (n=475). Both intervention and control groups received physical therapy for ≥0.5 hours per day. The following three outcomes were compared between groups: 1) disability, 2) transition to skilled nursing facility (SNF, post-acute care setting), and 3) 30-day readmission rate. Results: Disability was lower in the intervention group (28%) than in the control group (37%) (relative risk [RR] =0.74; 95% confidence interval [CI], 0.35–0.97; P=0.026), and transition to SNF was lower in the intervention group (22%) than in the control group (30%) (RR =0.77; 95% CI, 0.39–0.98; P=0.032). The 30-day readmission rate did not significantly differ between the two groups. Conclusion: SSA intervention enhanced the benefits of physical therapy for functionally declining older adults. When applied to older adults with heart failure in the form of daily multidisciplinary meetings, SSA intervention improved functional outcomes and reduced transfer to SNFs after hospitalization.Keywords: functionally impaired elderly, hospital communication system, hospital readmission, shared decision making, skilled nursing facility

Published
2014

5. Associations between the 2007 Medicare reimbursement reduction for bone mineral density testing and osteoporosis drug therapy patterns of female Medicare beneficiaries

Author

Kim SJ, Lee JH, Kim S, Nakagawa S, Bertelson H, Lam J, and Yoo JW

Subjects
Medicine (General), R5-920
Abstract

Sun Jung Kim,1,2 Joo Hun Lee,3 Sulgi Kim,4 Shunichi Nakagawa,5 Heather Bertelson,6 Julia Lam,7 Ji Won Yoo6,7 1Department of Public Health, 2Institute of Health Services Research, Yonsei University College of Medicine, 3Department of Media and Communication, Hanyang University College of Social Sciences, Seoul, Republic of Korea; 4Department of Epidemiology and Biostatistics, Case Western Reserve University, Cleveland, OH, USA; 5Department of Medicine, College of Physicians and Surgeons, Columbia University, New York, NY, USA; 6Department of Internal Medicine, Aurora Health Care, Milwaukee, WI, USA; 7Department of Medicine, University of Wisconsin School of Medicine and Public Health, Madison, WI, USA Objective: To examine how drug therapy patterns for osteoporosis have changed after the Medicare Physician Fee Schedule (MPFS) reimbursement reduction in 2007, in relation to follow-up bone mineral density (BMD) testing status. Methods: We used a retrospective temporal shift design to examine changes in drug therapy patterns before (Phase 1: January 1, 2005–December 31, 2006) and after (Phase 2: July 1, 2007–June 30, 2009) the MPFS reimbursement reduction in 2007, Cleveland, OH, USA. Participants were osteoporotic older women in Phase 1 (n=1,340) and Phase 2 (n=1,437). The main outcomes were a) adherence, b) adjustment, c) occurrence of an extended gap, and d) restarting drug therapy after an extended gap. Follow-up BMD testing status by study phase and location were also analyzed. Results: BMD testing rates at physicians’ offices decreased from 64.5% in Phase 1 to 58.4% in Phase 2 (P=0.02); however, testing rates in hospital outpatient settings increased (from 20.8% to 24.5%). There were also decreases in drug therapy adjustment from 15.9% in Phase 1 to 11.6% in Phase 2 (odds ratio [OR]: 0.73; P

Published
2014

7. The SLAC T-510 experiment for radio emission from particle showers: detailed simulation study and interpretation

Author

Bechtol, K., Belov, K., Borch, K., Chen, P., Clem, J., Gorham, P., Hast, C., Huege, T., Hyneman, R., Jobe, K., Kuwatani, K., Lam, J., Liu, T. C., Mulrey, K., Nam, J., Naudet, C., Nichol, R. J., Paciaroni, C., Rauch, B. F., Romero-Wolf, A., Rotter, B., Saltzberg, D., Schoorlemmer, H., Seckel, D., Strutt, B., Vieregg, A., Williams, C., Wissel, S., and Zilles, A.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

Over the last several decades, radio detection of air showers has been widely used to detect ultra-high-energy cosmic rays. We developed an experiment under controlled laboratory conditions at SLAC with which we measured the radio-frequency radiation from a charged particle shower produced by bunches of electrons as primaries with known energy. The shower took place in a target made of High Density Polyethylene located in a strong magnetic field. The experiment was designed so that Askaryan and magnetically-induced components of the radio emission could be measured independently. At the same time, we performed a detailed simulation of this experiment to predict the radio signal using two microscopic formalisms, endpoint and ZHS. In this paper, we present the simulation scheme and make a comparison with data characteristics such as linearity with magnetic field and amplitude. The simulations agree with the measurements within uncertainties and present a good description of the data. In particular, reflections within the target that accounted for the largest systematic uncertainties are addressed. The prediction of the amplitude of Askaryan emission agrees with measurements to within 5% for the endpoint formalism and 11% for the ZHS formalism. The amplitudes of magnetically-induced emission agree to within 5% for the endpoint formalism and less than 1% for the ZHS formalism. The agreement of the absolute scale of emission gives confidence in state-of-the-art air shower simulations which are based on the applied formalisms.

Published
2021
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8. Health Equity Implications of Missing Data Among Youths With Childhood‐Onset Systemic Lupus Erythematosus: A Proof‐of‐Concept Study in the Childhood Arthritis and Rheumatology Research Alliance Registry

Author

Woo, Jennifer M. P., Simmonds, Faith, Dennos, Anne, Son, Mary Beth F., Lewandowski, Laura B., Rubinstein, Tamar B., Abel, N., Abulaban, K., Adams, A., Adams, M., Agbayani, R., Aiello, J., Akoghlanian, S., Alejandro, C., Allenspach, E., Alperin, R., Alpizar, M., Amarilyo, G., Ambler, W., Anderson, E., Ardoin, S., Armendariz, S., Baker, E., Balboni, I., Balevic, S., Ballenger, L., Ballinger, S., Balmuri, N., Barbar‐Smiley, F., Barillas‐Arias, L., Basiaga, M., Baszis, K., Becker, M., Bell‐Brunson, H., Beltz, E., Benham, H., Benseler, S., Bernal, W., Beukelman, T., Bigley, T., Binstadt, B., Black, C., Blakley, M., Bohnsack, J., Boland, J., Boneparth, A., Bowman, S., Bracaglia, C., Brooks, E., Brothers, M., Brown, A., Brunner, H., Buckley, M., Buckley, M., Bukulmez, H., Bullock, D., Cameron, B., Canna, S., Cannon, L., Carper, P., Cartwright, V., Cassidy, E., Cerracchio, L., Chalom, E., Chang, J., Chang‐Hoftman, A., Chauhan, V., Chira, P., Chinn, T., Chundru, K., Clairman, H., Co, D., Confair, A., Conlon, H., Connor, R., Cooper, A., Cooper, J., Cooper, S., Correll, C., Corvalan, R., Costanzo, D., Cron, R., Curiel‐Duran, L., Curington, T., Curry, M., Dalrymple, A., Davis, A., Davis, C., Davis, C., Davis, T., De Benedetti, F., De Ranieri, D., Dean, J., Dedeoglu, F., DeGuzman, M., Delnay, N., Dempsey, V., DeSantis, E., Dickson, T., Dingle, J., Donaldson, B., Dorsey, E., Dover, S., Dowling, J., Drew, J., Driest, K., Du, Q., Duarte, K., Durkee, D., Duverger, E., Dvergsten, J., Eberhard, A., Eckert, M., Ede, K., Edelheit, B., Edens, C., Edens, C., Edgerly, Y., Elder, M., Ervin, B., Fadrhonc, S., Failing, C., Fair, D., Falcon, M., Favier, L., Federici, S., Feldman, B., Fennell, J., Ferguson, I., Ferguson, P., Ferreira, B., Ferrucho, R., Fields, K., Finkel, T., Fitzgerald, M., Fleming, C., Flynn, O., Fogel, L., Fox, E., Fox, M., Franco, L., Freeman, M., Fritz, K., Froese, S., Fuhlbrigge, R., Fuller, J., George, N., Gerhold, K., Gerstbacher, D., Gilbert, M., Gillispie‐Taylor, M., Giverc, E., Godiwala, C., Goh, I., Goheer, H., Goldsmith, D., Gotschlich, E., Gotte, A., Gottlieb, B., Gracia, C., Graham, T., Grevich, S., Griffin, T., Griswold, J., Grom, A., Guevara, M., Guittar, P., Guzman, M., Hager, M., Hahn, T., Halyabar, O., Hammelev, E., Hance, M., Hanson, A., Harel, L., Haro, S., Harris, J., Harry, O., Hartigan, E., Hausmann, J., Hay, A., Hayward, K., Heiart, J., Hekl, K., Henderson, L., Henrickson, M., Hersh, A., Hickey, K., Hill, P., Hillyer, S., Hiraki, L., Hiskey, M., Hobday, P., Hoffart, C., Holland, M., Hollander, M., Hong, S., Horwitz, M., Hsu, J., Huber, A., Huggins, J., Hui‐Yuen, J., Hung, C., Huntington, J., Huttenlocher, A., Ibarra, M., Imundo, L., Inman, C., Insalaco, A., Jackson, A., Jackson, S., James, K., Janow, G., Jaquith, J., Jared, S., Johnson, N., Jones, J., Jones, J., Jones, J., Jones, K., Jones, S., Joshi, S., Jung, L., Justice, C., Justiniano, A., Karan, N., Kaufman, K., Kemp, A., Kessler, E., Khalsa, U., Kienzle, B., Kim, S., Kimura, Y., Kingsbury, D., Kitcharoensakkul, M., Klausmeier, T., Klein, K., Klein‐Gitelman, M., Kompelien, B., Kosikowski, A., Kovalick, L., Kracker, J., Kramer, S., Kremer, C., Lai, J., Lam, J., Lang, B., Lapidus, S., Lapin, B., Lasky, A., Latham, D., Lawson, E., Laxer, R., Lee, P., Lee, P., Lee, T., Lentini, L., Lerman, M., Levy, D., Li, S., Lieberman, S., Lim, L., Lin, C., Ling, N., Lingis, M., Lo, M., Lovell, D., Lowman, D., Luca, N., Lvovich, S., Madison, C., Madison, J., Manzoni, S. Magni, Malla, B., Maller, J., Malloy, M., Mannion, M., Manos, C., Marques, L., Martyniuk, A., Mason, T., Mathus, S., McAllister, L., McCarthy, K., McConnell, K., McCormick, E., McCurdy, D., Stokes, P. McCurdy, McGuire, S., McHale, I., McMonagle, A., McMullen‐Jackson, C., Meidan, E., Mellins, E., Mendoza, E., Mercado, R., Merritt, A., Michalowski, L., Miettunen, P., Miller, M., Milojevic, D., Mirizio, E., Misajon, E., Mitchell, M., Modica, R., Mohan, S., Moore, K., Moorthy, L., Morgan, S., Dewitt, E. Morgan, Moss, C., Moussa, T., Mruk, V., Murphy, A., Muscal, E., Nadler, R., Nahal, B., Nanda, K., Nasah, N., Nassi, L., Nativ, S., Natter, M., Neely, J., Nelson, B., Newhall, L., Ng, L., Nicholas, J., Nicolai, R., Nigrovic, P., Nocton, J., Nolan, B., Oberle, E., Obispo, B., OʼBrien, B., OʼBrien, T., Okeke, O., Oliver, M., Olson, J., OʼNeil, K., Onel, K., Orandi, A., Orlando, M., Osei‐Onomah, S., Oz, R., Pagano, E., Paller, A., Pan, N., Panupattanapong, S., Pardeo, M., Paredes, J., Parsons, A., Patel, J., Pentakota, K., Pepmueller, P., Pfeiffer, T., Phillippi, K., Phillippi, K., Marafon, D. Pires, Ponder, L., Pooni, R., Prahalad, S., Pratt, S., Protopapas, S., Puplava, B., Quach, J., Quinlan‐Waters, M., Rabinovich, C., Radhakrishna, S., Rafko, J., Raisian, J., Rakestraw, A., Ramirez, C., Ramsay, E., Ramsey, S., Randell, R., Reed, A., Reed, A., Reed, A., Reid, H., Remmel, K., Repp, A., Reyes, A., Richmond, A., Riebschleger, M., Ringold, S., Riordan, M., Riskalla, M., Ritter, M., Rivas‐Chacon, R., Robinson, A., Rodela, E., Rodriquez, M., Rojas, K., Ronis, T., Rosenkranz, M., Rosolowski, B., Rothermel, H., Rothman, D., Roth‐Wojcicki, E., Rouster‐Stevens, K., Rubinstein, T., Ruth, N., Saad, N., Sabbagh, S., Sacco, E., Sadun, R., Sandborg, C., Sanni, A., Santiago, L., Sarkissian, A., Savani, S., Scalzi, L., Schanberg, L., Scharnhorst, S., Schikler, K., Schlefman, A., Schmeling, H., Schmidt, K., Schmitt, E., Schneider, R., Schollaert‐Fitch, K., Schulert, G., Seay, T., Seper, C., Shalen, J., Sheets, R., Shelly, A., Shenoi, S., Shergill, K., Shirley, J., Shishov, M., Shivers, C., Silverman, E., Singer, N., Sivaraman, V., Sletten, J., Smith, A., Smith, C., Smith, J., Smith, J., Smitherman, E., Soep, J., Son, M., Spence, S., Spiegel, L., Spitznagle, J., Sran, R., Srinivasalu, H., Stapp, H., Steigerwald, K., Rakovchik, Y. Sterba, Stern, S., Stevens, A., Stevens, B., Stevenson, R., Stewart, K., Stingl, C., Stokes, J., Stoll, M., Stringer, E., Sule, S., Sumner, J., Sundel, R., Sutter, M., Syed, R., Syverson, G., Szymanski, A., Taber, S., Tal, R., Tambralli, A., Taneja, A., Tanner, T., Tapani, S., Tarshish, G., Tarvin, S., Tate, L., Taxter, A., Taylor, J., Terry, M., Tesher, M., Thatayatikom, A., Thomas, B., Tiffany, K., Ting, T., Tipp, A., Toib, D., Torok, K., Toruner, C., Tory, H., Toth, M., Tse, S., Tubwell, V., Twilt, M., Uriguen, S., Valcarcel, T., Van Mater, H., Vannoy, L., Varghese, C., Vasquez, N., Vazzana, K., Vehe, R., Veiga, K., Velez, J., Verbsky, J., Vilar, G., Volpe, N., von Scheven, E., Vora, S., Wagner, J., Wagner‐Weiner, L., Wahezi, D., Waite, H., Walker, J., Walters, H., Muskardin, T. Wampler, Waqar, L., Waterfield, M., Watson, M., Watts, A., Weiser, P., Weiss, J., Weiss, P., Wershba, E., White, A., Williams, C., Wise, A., Woo, J., Woolnough, L., Wright, T., Wu, E., Yalcindag, A., Yee, M., Yen, E., Yeung, R., Yomogida, K., Yu, Q., Zapata, R., Zartoshti, A., Zeft, A., Zeft, R., Zhang, Y., Zhao, Y., Zhu, A., and Zic, C.

Published
2023
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11. Childhood‐Onset Lupus Nephritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: Short‐Term Kidney Status and Variation in Care

Author

Smitherman, Emily A., Chahine, Rouba A., Beukelman, Timothy, Lewandowski, Laura B., Rahman, A. K. M. Fazlur, Wenderfer, Scott E., Curtis, Jeffrey R., Hersh, Aimee O., Abel, N., Abulaban, K., Adams, A., Adams, M., Agbayani, R., Aiello, J., Akoghlanian, S., Alejandro, C., Allenspach, E., Alperin, R., Alpizar, M., Amarilyo, G., Ambler, W., Anderson, E., Ardoin, S., Armendariz, S., Baker, E., Balboni, I., Balevic, S., Ballenger, L., Ballinger, S., Balmuri, N., Barbar‐Smiley, F., Barillas‐Arias, L., Basiaga, M., Baszis, K., Becker, M., Bell‐Brunson, H., Beltz, E., Benham, H., Benseler, S., Bernal, W., Beukelman, T., Bigley, T., Binstadt, B., Black, C., Blakley, M., Bohnsack, J., Boland, J., Boneparth, A., Bowman, S., Bracaglia, C., Brooks, E., Brothers, M., Brown, A., Brunner, H., Buckley, M., Buckley, M., Bukulmez, H., Bullock, D., Cameron, B., Canna, S., Cannon, L., Carper, P., Cartwright, V., Cassidy, E., Cerracchio, L., Chalom, E., Chang, J., Chang‐Hoftman, A., Chauhan, V., Chira, P., Chinn, T., Chundru, K., Clairman, H., Co, D., Confair, A., Conlon, H., Connor, R., Cooper, A., Cooper, J., Cooper, S., Correll, C., Corvalan, R., Costanzo, D., Cron, R., Curiel‐Duran, L., Curington, T., Curry, M., Dalrymple, A., Davis, A., Davis, C., Davis, C., Davis, T., De Benedetti, F., De Ranieri, D., Dean, J., Dedeoglu, F., DeGuzman, M., Delnay, N., Dempsey, V., DeSantis, E., Dickson, T., Dingle, J., Donaldson, B., Dorsey, E., Dover, S., Dowling, J., Drew, J., Driest, K., Du, Q., Duarte, K., Durkee, D., Duverger, E., Dvergsten, J., Eberhard, A., Eckert, M., Ede, K., Edelheit, B., Edens, C., Edens, C., Edgerly, Y., Elder, M., Ervin, B., Fadrhonc, S., Failing, C., Fair, D., Falcon, M., Favier, L., Federici, S., Feldman, B., Fennell, J., Ferguson, I., Ferguson, P., Ferreira, B., Ferrucho, R., Fields, K., Finkel, T., Fitzgerald, M., Fleming, C., Flynn, O., Fogel, L., Fox, E., Fox, M., Franco, L., Freeman, M., Fritz, K., Froese, S., Fuhlbrigge, R., Fuller, J., George, N., Gerhold, K., Gerstbacher, D., Gilbert, M., Gillispie‐Taylor, M., Giverc, E., Godiwala, C., Goh, I., Goheer, H., Goldsmith, D., Gotschlich, E., Gotte, A., Gottlieb, B., Gracia, C., Graham, T., Grevich, S., Griffin, T., Griswold, J., Grom, A., Guevara, M., Guittar, P., Guzman, M., Hager, M., Hahn, T., Halyabar, O., Hammelev, E., Hance, M., Hanson, A., Harel, L., Haro, S., Harris, J., Harry, O., Hartigan, E., Hausmann, J., Hay, A., Hayward, K., Heiart, J., Hekl, K., Henderson, L., Henrickson, M., Hersh, A., Hickey, K., Hill, P., Hillyer, S., Hiraki, L., Hiskey, M., Hobday, P., Hoffart, C., Holland, M., Hollander, M., Hong, S., Horwitz, M., Hsu, J., Huber, A., Huggins, J., Hui‐Yuen, J., Hung, C., Huntington, J., Huttenlocher, A., Ibarra, M., Imundo, L., Inman, C., Insalaco, A., Jackson, A., Jackson, S., James, K., Janow, G., Jaquith, J., Jared, S., Johnson, N., Jones, J., Jones, J., Jones, J., Jones, K., Jones, S., Joshi, S., Jung, L., Justice, C., Justiniano, A., Karan, N., Kaufman, K., Kemp, A., Kessler, E., Khalsa, U., Kienzle, B., Kim, S., Kimura, Y., Kingsbury, D., Kitcharoensakkul, M., Klausmeier, T., Klein, K., Klein‐Gitelman, M., Kompelien, B., Kosikowski, A., Kovalick, L., Kracker, J., Kramer, S., Kremer, C., Lai, J., Lam, J., Lang, B., Lapidus, S., Lapin, B., Lasky, A., Latham, D., Lawson, E., Laxer, R., Lee, P., Lee, P., Lee, T., Lentini, L., Lerman, M., Levy, D., Li, S., Lieberman, S., Lim, L., Lin, C., Ling, N., Lingis, M., Lo, M., Lovell, D., Lowman, D., Luca, N., Lvovich, S., Madison, C., Madison, J., Manzoni, S. Magni, Malla, B., Maller, J., Malloy, M., Mannion, M., Manos, C., Marques, L., Martyniuk, A., Mason, T., Mathus, S., McAllister, L., McCarthy, K., McConnell, K., McCormick, E., McCurdy, D., Stokes, P. McCurdy, McGuire, S., McHale, I., McMonagle, A., McMullen‐Jackson, C., Meidan, E., Mellins, E., Mendoza, E., Mercado, R., Merritt, A., Michalowski, L., Miettunen, P., Miller, M., Milojevic, D., Mirizio, E., Misajon, E., Mitchell, M., Modica, R., Mohan, S., Moore, K., Moorthy, L., Morgan, S., Dewitt, E. Morgan, Moss, C., Moussa, T., Mruk, V., Murphy, A., Muscal, E., Nadler, R., Nahal, B., Nanda, K., Nasah, N., Nassi, L., Nativ, S., Natter, M., Neely, J., Nelson, B., Newhall, L., Ng, L., Nicholas, J., Nicolai, R., Nigrovic, P., Nocton, J., Nolan, B., Oberle, E., Obispo, B., OʼBrien, B., OʼBrien, T., Okeke, O., Oliver, M., Olson, J., OʼNeil, K., Onel, K., Orandi, A., Orlando, M., Osei‐Onomah, S., Oz, R., Pagano, E., Paller, A., Pan, N., Panupattanapong, S., Pardeo, M., Paredes, J., Parsons, A., Patel, J., Pentakota, K., Pepmueller, P., Pfeiffer, T., Phillippi, K., Marafon, D. Pires, Phillippi, K., Ponder, L., Pooni, R., Prahalad, S., Pratt, S., Protopapas, S., Puplava, B., Quach, J., Quinlan‐Waters, M., Rabinovich, C., Radhakrishna, S., Rafko, J., Raisian, J., Rakestraw, A., Ramirez, C., Ramsay, E., Ramsey, S., Randell, R., Reed, A., Reed, A., Reed, A., Reid, H., Remmel, K., Repp, A., Reyes, A., Richmond, A., Riebschleger, M., Ringold, S., Riordan, M., Riskalla, M., Ritter, M., Rivas‐Chacon, R., Robinson, A., Rodela, E., Rodriquez, M., Rojas, K., Ronis, T., Rosenkranz, M., Rosolowski, B., Rothermel, H., Rothman, D., Roth‐Wojcicki, E., Rouster – Stevens, K., Rubinstein, T., Ruth, N., Saad, N., Sabbagh, S., Sacco, E., Sadun, R., Sandborg, C., Sanni, A., Santiago, L., Sarkissian, A., Savani, S., Scalzi, L., Schanberg, L., Scharnhorst, S., Schikler, K., Schlefman, A., Schmeling, H., Schmidt, K., Schmitt, E., Schneider, R., Schollaert‐Fitch, K., Schulert, G., Seay, T., Seper, C., Shalen, J., Sheets, R., Shelly, A., Shenoi, S., Shergill, K., Shirley, J., Shishov, M., Shivers, C., Silverman, E., Singer, N., Sivaraman, V., Sletten, J., Smith, A., Smith, C., Smith, J., Smith, J., Smitherman, E., Soep, J., Son, M., Spence, S., Spiegel, L., Spitznagle, J., Sran, R., Srinivasalu, H., Stapp, H., Steigerwald, K., Rakovchik, Y. Sterba, Stern, S., Stevens, A., Stevens, B., Stevenson, R., Stewart, K., Stingl, C., Stokes, J., Stoll, M., Stringer, E., Sule, S., Sumner, J., Sundel, R., Sutter, M., Syed, R., Syverson, G., Szymanski, A., Taber, S., Tal, R., Tambralli, A., Taneja, A., Tanner, T., Tapani, S., Tarshish, G., Tarvin, S., Tate, L., Taxter, A., Taylor, J., Terry, M., Tesher, M., Thatayatikom, A., Thomas, B., Tiffany, K., Ting, T., Tipp, A., Toib, D., Torok, K., Toruner, C., Tory, H., Toth, M., Tse, S., Tubwell, V., Twilt, M., Uriguen, S., Valcarcel, T., Van Mater, H., Vannoy, L., Varghese, C., Vasquez, N., Vazzana, K., Vehe, R., Veiga, K., Velez, J., Verbsky, J., Vilar, G., Volpe, N., von Scheven, E., Vora, S., Wagner, J., Wagner‐Weiner, L., Wahezi, D., Waite, H., Walker, J., Walters, H., Muskardin, T. Wampler, Waqar, L., Waterfield, M., Watson, M., Watts, A., Weiser, P., Weiss, J., Weiss, P., Wershba, E., White, A., Williams, C., Wise, A., Woo, J., Woolnough, L., Wright, T., Wu, E., Yalcindag, A., Yee, M., Yen, E., Yeung, R., Yomogida, K., Yu, Q., Zapata, R., Zartoshti, A., Zeft, A., Zeft, R., Zhang, Y., Zhao, Y., Zhu, A., and Zic, C.

Published
2023
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14. Upward-Pointing Cosmic-Ray-like Events Observed with ANITA

Author

Romero-Wolf, Andres, Gorham, P. W., Nam, J., Hoover, S., Allison, P., Banerjee, O., Batten, L., Beatty, J. J., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Clem, J. M., Connolly, A., Dailey, B., Deaconu, C., Cremonesi, L., Dowkontt, P. F., DuVernois, M. A., Field, R. C., Fox, B. D., Goldstein, D., Gordon, J., Hast, C., Hebert, C. L., Hill, B., Hughes, K., Hupe, R., Israel, M. H., Javaid, A., Kowalski, J., Lam, J., Ludwig, A., Learned, J. G., Liewer, K. M., Liu, T. C., Link, J. T., Lusczek, E., Matsuno, S., Mercurio, B. C., Miki, C., Miocinovic, P., Mottram, M., Mulrey, K., Naudet, C. J., Ng, J., Nichol, R. J., Novikov, A., Palladino, K., Prohira, S., Rauch, B. F., Reil, K., Roberts, J., Rosen, M., Rotter, B., Russell, J., Ruckman, L., Saltzberg, D., Seckel, D., Stafford, S., Stockham, J., Stockham, M., Strutt, B., Tatem, K., Varner, G. S., Vieregg, A. G., Walz, D., Wissel, S. A., Wu, F., Alvarez-Muñiz, J., Carvalho Jr., W., Schoorlemmer, H., and Zas, E.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

These proceedings address a recent publication by the ANITA collaboration of four upward- pointing cosmic-ray-like events observed in the first flight of ANITA. Three of these events were consistent with stratospheric cosmic-ray air showers where the axis of propagation does not inter- sect the surface of the Earth. The fourth event was consistent with a primary particle that emerges from the surface of the ice suggesting a possible {\tau}-lepton decay as the origin of this event. These proceedings follow-up on the modeling and testing of the hypothesis that this event was of {\tau} neutrino origin., Comment: 8 pages, 3 figures, presented at the International Cosmic Ray Conference 2017, Busan, South Korea

Published
2018

15. Observation of an Unusual Upward-going Cosmic-ray-like Event in the Third Flight of ANITA

Author

Gorham, P. W., Rotter, B., Allison, P., Banerjee, O., Batten, L., Beatty, J. J., Bechtol, K., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C. C., Chen, C. H., Chen, P., Clem, J. M., Connolly, A., Cremonesi, L., Dailey, B., Deaconu, C., Dowkontt, P. F., Fox, B. D., Gordon, J. W. H., Hast, C., Hill, B., Hughes, K., Huang, J. J., Hupe, R., Israel, M. H., Javaid, A., Lam, J., Liewer, K. M., Lin, S. Y., Liu, T. C., Ludwig, A., Macchiarulo, L., Matsuno, S., Miki, C., Mulrey, K., Nam, J., Naudet, C. J., Nichol, R. J., Novikov, A., Oberla, E., Olmedo, M., Prechelt, R., Prohira, S., Rauch, B. F., Roberts, J. M., Romero-Wolf, A., Russell, J. W., Saltzberg, D., Seckel, D., Schoorlemmer, H., Shiao, J., Stafford, S., Stockham, J., Stockham, M., Strutt, B., Varner, G. S., Vieregg, A. G., Wang, S. H., and Wissel, S. A.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on an upward traveling, radio-detected cosmic-ray-like impulsive event with characteristics closely matching an extensive air shower. This event, observed in the third flight of the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload, is consistent with a similar event reported in a previous flight. These events may be produced by the atmospheric decay of an upward-propagating $\tau$-lepton produced by a $\nu_{\tau}$ interaction, although their relatively steep arrival angles create tension with the standard model (SM) neutrino cross section. Each of the two events have $a~posteriori$ background estimates of $\lesssim 10^{-2}$ events. If these are generated by $\tau$-lepton decay, then either the charged-current $\nu_{\tau}$ cross section is suppressed at EeV energies, or the events arise at moments when the peak flux of a transient neutrino source was much larger than the typical expected cosmogenic background neutrinos., Comment: 5 pages, 4 figures. Supplemental material available from corresponding author by request

Published
2018
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16. Antarctic Surface Reflectivity Calculations and Measurements from the ANITA-4 and HiCal-2 Experiments

Author

Prohira, S., Novikov, A., Dasgupta, P., Jain, P., Nande, S., Allison, P., Banerjee, O., Batten, L., Beatty, J. J., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Clem, J. M., Connolly, A., Cremonesi, L., Dailey, B., Deaconu, C., Dowkontt, P. F., Fox, B. D., Gordon, J., Gorham, P. W., Hast, C., Hill, B., Hupe, R., Israel, M. H., Lam, J., Liu, T. C., Ludwig, A., Matsuno, S., Miki, C., Mottram, M., Mulrey, K., Nam, J., Nichol, R. J., Oberla, E., Ratzlaff, K., Rauch, B. F., Romero-Wolf, A., Rotter, B., Russell, J., Saltzberg, D., Seckel, D., Schoorlemmer, H., Stafford, S., Stockham, J., Stockham, M., Strutt, B., Tatem, K., Varner, G. S., Vieregg, A. G., Wissel, S. A., Wu, F., and Young, R.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The balloon-borne HiCal radio-frequency (RF) transmitter, in concert with the ANITA radio-frequency receiver array, is designed to measure the Antarctic surface reflectivity in the RF wavelength regime. The amplitude of surface-reflected transmissions from HiCal, registered as triggered events by ANITA, can be compared with the direct transmissions preceding them by O(10) microseconds, to infer the surface power reflection coefficient $\cal{R}$. The first HiCal mission (HiCal-1, Jan. 2015) yielded a sample of 100 such pairs, resulting in estimates of $\cal{R}$ at highly-glancing angles (i.e., zenith angles approaching $90^\circ$), with measured reflectivity for those events which exceeded extant calculations. The HiCal-2 experiment, flying from Dec., 2016-Jan., 2017, provided an improvement by nearly two orders of magnitude in our event statistics, allowing a considerably more precise mapping of the reflectivity over a wider range of incidence angles. We find general agreement between the HiCal-2 reflectivity results and those obtained with the earlier HiCal-1 mission, as well as estimates from Solar reflections in the radio-frequency regime. In parallel, our calculations of expected reflectivity have matured; herein, we use a plane-wave expansion to estimate the reflectivity R from both a flat, smooth surface (and, in so doing, recover the Fresnel reflectivity equations) and also a curved surface. Multiplying our flat-smooth reflectivity by improved Earth curvature and surface roughness corrections now provides significantly better agreement between theory and the HiCal 2a/2b measurements., Comment: submitted to Astropart. Phys

Published
2018
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18. HiCal 2: An instrument designed for calibration of the ANITA experiment and for Antarctic surface reflectivity measurements

Author

Prohira, S., Novikov, A., Besson, D. Z., Ratzlaff, K., Stockham, J., Stockham, M., Clem, J. M., Young, R., Gorham, P. W., Allison, P., Banerjee, O., Batten, L., Beatty, J. J., Belov, K., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Connolly, A., Cremonesi, L., Dailey, B., Deaconu, C., Dowkontt, P. F., Fox, B. D., Gordon, J., Hast, C., Hill, B., Hupe, R., Israel, M. H., Kowalski, J., Lam, J., Learned, J. G., Liewer, K. M., Liu, T. C., Ludwig, A., Matsuno, S., Miki, C., Mottram, M., Mulrey, K., Nam, J., Nichol, R. J., Oberla, E., Rauch, B. F., Roberts, J., Romero-Wolf, A., Rotter, B., Russell, J., Saltzberg, D., Schoorlemmer, H., Seckel, D., Stafford, S., Strutt, B., Tatem, K., Varner, G. S., Vieregg, A. G., Wissel, S. A., and Wu, F.

Subjects
Physics - Instrumentation and Detectors
Abstract

The NASA supported High-Altitude Calibration (HiCal)-2 instrument flew as a companion balloon to the ANITA-4 experiment in December 2016. Based on a HV discharge pulser producing radio-frequency (RF) calibration pulses, HiCal-2 comprised two payloads, which flew for a combined 18 days, covering 1.5 revolutions of the Antarctic continent. ANITA-4 captured over 10,000 pulses from HiCal, both direct and reflected from the surface, at distances varying from 100-800 km, providing a large dataset for surface reflectivity measurements. Herein we present details on the design, construction and performance of HiCal-2., Comment: Published in NIM-A, final version

Published
2017
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19. Dynamic tunable notch filters for the Antarctic Impulsive Transient Antenna (ANITA)

Author

Allison, P., Banerjee, O., Beatty, J. J., Connolly, A., Deaconu, C., Gordon, J., Gorham, P. W., Kovacevich, M., Miki, C., Oberla, E., Roberts, J., Rotter, B., Stafford, S., Tatem, K., Batten, L., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Chen, Y., Clem, J. M., Cremonesi, L., Dailey, B., Dowkontt, P. F., Hsu, S., Huang, J., Hupe, R., Israel, M. H., Kowalski, J., Lam, J., Learned, J. G., Liewer, K. M., Liu, T. C., Ludwig, A., Matsuno, S., Mulrey, K., Nam, J., Nichol, R. J., Novikov, A., Prohira, S., Rauch, B. F., Ripa, J., Romero-Wolf, A., Russell, J., Saltzberg, D., Seckel, D., Shiao, J., Stockham, J., Stockham, M., Strutt, B., Varner, G. S., Vieregg, A. G., Wang, S., Wissel, S. A., Wu, F., and Young, R.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The Antarctic Impulsive Transient Antenna (ANITA) is a NASA long-duration balloon experiment with the primary goal of detecting ultra-high-energy ($>10^{18}\,\mbox{eV}$) neutrinos via the Askaryan Effect. The fourth ANITA mission, ANITA-IV, recently flew from Dec 2 to Dec 29, 2016. For the first time, the Tunable Universal Filter Frontend (TUFF) boards were deployed for mitigation of narrow-band, anthropogenic noise with tunable, switchable notch filters. The TUFF boards also performed second-stage amplification by approximately 45 dB to boost the $\sim\,\mu\mbox{V-level}$ radio frequency (RF) signals to $\sim$ mV-level for digitization, and supplied power via bias tees to the first-stage, antenna-mounted amplifiers. The other major change in signal processing in ANITA-IV is the resurrection of the $90^{\circ}$ hybrids deployed previously in ANITA-I, in the trigger system, although in this paper we focus on the TUFF boards. During the ANITA-IV mission, the TUFF boards were successfully operated throughout the flight. They contributed to a factor of 2.8 higher total instrument livetime on average in ANITA-IV compared to ANITA-III due to reduction of narrow-band, anthropogenic noise before a trigger decision is made., Comment: 27 pages, 19 figures

Published
2017
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20. Antarctic Surface Reflectivity Measurements from the ANITA-3 and HiCal-1 Experiments

Author

Gorham, P. W., Allison, P., Banerjee, O., Beatty, J. J., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Clem, J. M., Connolly, A., Dailey, B., Dasgupta, P., Deaconu, C., Cremonesi, L., Dowkontt, P. F., Fox, B. D., Gordon, J., Hill, B., Hupe, R., Israel, M. H., Jain, P., Kowalski, J., Lam, J., Learned, J. G., Liewer, K. M., Liu, T. C., Matsuno, S., Miki, C., Mottram, M., Mulrey, K., Nam, J., Nichol, R. J., Novikov, A., Oberla, E., Prohira, S., Rauch, B. F., Romero-Wolf, A., Rotter, B., Ratzlaff, K., Russell, J., Saltzberg, D., Seckel, D., Schoorlemmer, H., Stafford, S., Stockham, J., Stockham, M., Strutt, B., Tatem, K., Varner, G. S., Vieregg, A. G., Wissel, S. A., Wu, F., and Young, R.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena
Abstract

The primary science goal of the NASA-sponsored ANITA project is measurement of ultra-high energy neutrinos and cosmic rays, observed via radio-frequency signals resulting from a neutrino- or cosmic ray- interaction with terrestrial matter (atmospheric or ice molecules, e.g.). Accurate inference of the energies of these cosmic rays requires understanding the transmission/reflection of radio wave signals across the ice-air boundary. Satellite-based measurements of Antarctic surface reflectivity, using a co-located transmitter and receiver, have been performed more-or-less continuously for the last few decades. Satellite-based reflectivity surveys, at frequencies ranging from 2--45 GHz and at near-normal incidence, yield generally consistent reflectivity maps across Antarctica. Using the Sun as an RF source, and the ANITA-3 balloon borne radio-frequency antenna array as the RF receiver, we have also measured the surface reflectivity over the interval 200-1000 MHz, at elevation angles of 12-30 degrees, finding agreement with the Fresnel equations within systematic errors. To probe low incidence angles, inaccessible to the Antarctic Solar technique and not probed by previous satellite surveys, a novel experimental approach ("HiCal-1") was devised. Unlike previous measurements, HiCal-ANITA constitute a bi-static transmitter-receiver pair separated by hundreds of kilometers. Data taken with HiCal, between 200--600 MHz shows a significant departure from the Fresnel equations, constant with frequency over that band, with the deficit increasing with obliquity of incidence, which we attribute to the combined effects of possible surface roughness, surface grain effects, radar clutter and/or shadowing of the reflection zone due to Earth curvature effects., Comment: updated to match publication version

Published
2017

21. Characteristics of Four Upward-pointing Cosmic-ray-like Events Observed with ANITA

Author

Gorham, P. W., Nam, J., Romero-Wolf, A., Hoover, S., Allison, P., Banerjee, O., Beatty, J. J., Belov, K., Besson, D. Z., Binns, W. R., Bugaev, V., Cao, P., Chen, C., Chen, P., Clem, J. M., Connolly, A., Dailey, B., Deaconu, C., Cremonesi, L., Dowkonnt, P. F., Duvernois, M. A., Field, R. C., Fox, B. D., Goldstein, D., Gordon, J., Hast, C., Hebert, C. L., Hill, B., Hughes, K., Hupe, R., Israel, M. H., Javaid, A., Kowalski, J., Lam, J., Learned, J. G., Liewer, K. M., Liu, T. C., Link, J. T., Lusczek, E., Matsuno, S., Mercurio, B. C., Miki, C., Miocinovic, P., Mottram, M., Mulrey, K., Naudet, C. J., Ng, J., Nichol, R. J., Palladino, K., Rauch, B. F., Reil, K., Roberts, J., Rosen, M., Rotter, B., Russell, J., Ruckman, L., Saltzberg, D., Seckel, D., Schoorlemmer, H., Stafford, S., Stockham, J., Stockham, M., Strutt, B., Tatem, K., Varner, G. S., Vieregg, A. G., Walz, D., Wissel, S. A., and Wu, F.

Subjects
Astrophysics - High Energy Astrophysical Phenomena
Abstract

We report on four radio-detected cosmic-ray (CR) or CR-like events observed with the Antarctic Impulsive Transient Antenna (ANITA), a NASA-sponsored long-duration balloon payload. Two of the four were previously identified as stratospheric CR air showers during the ANITA-I flight. A third stratospheric CR was detected during the ANITA-II flight. Here we report on characteristics these three unusual CR events, which develop nearly horizontally, 20-30~km above the surface of the Earth. In addition, we report on a fourth steeply upward-pointing ANITA-I CR-like radio event which has characteristics consistent with a primary that emerged from the surface of the ice. This suggests a possible $\tau$-lepton decay as the origin of this event, but such an interpretation would require significant suppression of the Standard Model ${\tau}$-neutrino cross section., Comment: 5pp,4 figures, referees' comments addressed, this version accepted to Phys. Rev. Letters. Supplemental PDF material available; see source files

Published
2016
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22. Accelerator measurements of magnetically-induced radio emission from particle cascades with applications to cosmic-ray air showers

Author

Belov, K., Mulrey, K., Romero-Wolf, A., Wissel, S. A., Zilles, A., Bechtol, K., Borch, K., Chen, P., Clem, J., Gorham, P. W., Hast, C., Huege, T., Hyneman, R., Jobe, K., Kuwatani, K., Lam, J., Liu, T., Nam, J., Naudet, C., Nichol, R., Rauch, B. F., Rotter, B., Saltzberg, D., Schoorlemmer, H., Seckel, D., Strutt, B., Vieregg, A. G., and Williams, C.

Subjects
Astrophysics - Instrumentation and Methods for Astrophysics, Astrophysics - High Energy Astrophysical Phenomena, High Energy Physics - Experiment
Abstract

For fifty years, cosmic-ray air showers have been detected by their radio emission. We present the first laboratory measurements that validate electrodynamics simulations used in air shower modeling. An experiment at SLAC provides a beam test of radio-frequency (RF) radiation from charged particle cascades in the presence of a magnetic field, a model system of a cosmic-ray air shower. This experiment provides a suite of controlled laboratory measurements to compare to particle-level simulations of RF emission, which are relied upon in ultra-high-energy cosmic-ray air shower detection. We compare simulations to data for intensity, linearity with magnetic field, angular distribution, polarization, and spectral content. In particular, we confirm modern predictions that the magnetically induced emission in a dielectric forms a cone that peaks at the Cherenkov angle and show that the simulations reproduce the data within systematic uncertainties., Comment: 5 pages, 7 figures

Published
2015
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23. Energy and Flux Measurements of Ultra-High Energy Cosmic Rays Observed During the First ANITA Flight

Author

Schoorlemmer, H., Belov, K., Romero-Wolf, A., García-Fernández, D., Bugaev, V., Wissel, S. A., Allison, P., Alvarez-Muñiz, J., Barwick, S. W., Beatty, J. J., Besson, D. Z., Binns, W. R., Carvalho Jr., W. R., Chen, C., Chen, P., Clem, J. M., Connolly, A., Dowkontt, P. F., DuVernois, M. A., Field, R. C., Goldstein, D., Gorham, P. W., Hast, C., Heber, C. L., Huege, T., Hoover, S., Israel, M. H., Javaid, A., Kowalski, J., Lam, J., Learned, J. G., Liewer, K. M., Link, J. T., Lusczek, E., Matsuno, S., Mercurio, B. C., Miki, C., Miočinović, P., Mulrey, K., Nam, J., Naudet, C. J., Ng, J., Nichol, R. J., Palladino, K., Rauch, B. F., Roberts, J., Reil, K., Rotter, B., Rosen, M., Ruckman, L., Saltzberg, D., Seckel, D., Urdaneta, D., Varner, G. S., Vieregg, A. G., Walz, D., Wu, F., and Zas, E.

Subjects
Astrophysics - High Energy Astrophysical Phenomena, Astrophysics - Instrumentation and Methods for Astrophysics
Abstract

The first flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment recorded 16 radio signals that were emitted by cosmic-ray induced air showers. For 14 of these events, this radiation was reflected from the ice. The dominant contribution to the radiation from the deflection of positrons and electrons in the geomagnetic field, which is beamed in the direction of motion of the air shower. This radiation is reflected from the ice and subsequently detected by the ANITA experiment at a flight altitude of 36km. In this paper, we estimate the energy of the 14 individual events and find that the mean energy of the cosmic-ray sample is 2.9 EeV. By simulating the ANITA flight, we calculate its exposure for ultra-high energy cosmic rays. We estimate for the first time the cosmic-ray flux derived only from radio observations. In addition, we find that the Monte Carlo simulation of the ANITA data set is in agreement with the total number of observed events and with the properties of those events., Comment: Added more explanation of the experimental setup and textual improvements

Published
2015
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24. Collisional trap losses of cold, magnetically-trapped Br atoms

Author

Lam, J., Rennick, C. J., and Softley, T. P.

Subjects
Physics - Atomic Physics, Physics - Chemical Physics
Abstract

Near-threshold photodissociation of Br$_2$ from a supersonic beam produces slow bromine atoms that are trapped in the magnetic field minimum formed between two opposing permanent magnets. Here, we quantify the dominant trap loss rate due to collisions with two sources of residual gas: the background limited by the vacuum chamber base pressure, and the carrier gas during the supersonic gas pulse. The loss rate due to collisions with residual Ar in the background follows pseudo first-order kinetics, and the bimolecular rate coefficient for collisional loss from the trap is determined by measurement of this rate as a function of the background Ar pressure. This rate coefficient is smaller than the total elastic collision rate coefficient, as it only samples those collisions that lead to trap loss, and is determined to be $\langle\nu\sigma\rangle = (1.12\pm0.09)\times10^{-9}\,\text{cm}^3\, \text{s}^{-1}$. The calculated differential cross section can be used with this value to estimate a trap depth of $293\pm24\,\text{mK}$. Carrier gas collisions occur only during the tail of the supersonic beam pulse. Using the differential cross section verified by the background-gas collision measurements provides an estimate of the peak molecular beam density of $(3.0\pm0.3)\times10^{13}\,\text{cm}^{-3}$ in good agreement with the prediction of a simple supersonic expansion model. Finally, we estimate the trap loss rate due to Majorana transitions to be negligible, owing to the relatively large trapped-atom phase-space volume.

Published
2014
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26. A hybrid approach for de novo human genome sequence assembly and phasing

Author

Kwok, Pui-Yan, Mostovoy, Y, Levy-Sakin, M, Lam, J, Lam, ET, Hastie, AR, Marks, P, Lee, J, Chu, C, Lin, C, and Dzakula, Z

Abstract

Despite tremendous progress in genome sequencing, the basic goal of producing a phased (haplotype-resolved) genome sequence with end-to-end contiguity for each chromosome at reasonable cost and effort is still unrealized. In this study, we describe an appr

Published
2016

27. Energy and flux measurements of ultra-high energy cosmic rays observed during the first ANITA flight

Author

Schoorlemmer, H, Belov, K, Romero-Wolf, A, García-Fernández, D, Bugaev, V, Wissel, SA, Allison, P, Alvarez-Muñiz, J, Barwick, SW, Beatty, JJ, Besson, DZ, Binns, WR, Carvalho, WR, Chen, C, Chen, P, Clem, JM, Connolly, A, Dowkontt, PF, DuVernois, MA, Field, RC, Goldstein, D, Gorham, PW, Hast, C, Huege, T, Heber, CL, Hoover, S, Israel, MH, Javaid, A, Kowalski, J, Lam, J, Learned, JG, Link, JT, Lusczek, E, Matsuno, S, Mercurio, BC, Miki, C, Miočinović, P, Mulrey, K, Nam, J, Naudet, CJ, Ng, J, Nichol, RJ, Palladino, K, Rauch, BF, Roberts, J, Reil, K, Rotter, B, Rosen, M, Ruckman, L, Saltzberg, D, Seckel, D, Urdaneta, D, Varner, GS, Vieregg, AG, Walz, D, Wu, F, and Zas, E

Subjects
Nuclear and Plasma Physics, Particle and High Energy Physics, Physical Sciences, Cosmic rays, Air shower, Radio detection, astro-ph.HE, astro-ph.IM, Astronomical and Space Sciences, Atomic, Molecular, Nuclear, Particle and Plasma Physics, Nuclear & Particles Physics, Astronomical sciences, Particle and high energy physics
Abstract

The first flight of the Antarctic Impulsive Transient Antenna (ANITA) experiment recorded 16 radio signals that were emitted by cosmic-ray induced air showers. The dominant contribution to the radiation comes from the deflection of positrons and electrons in the geomagnetic field, which is beamed in the direction of motion of the air shower. For 14 of these events, this radiation is reflected from the ice and subsequently detected by the ANITA experiment at a flight altitude of ∼36 km. In this paper, we estimate the energy of the 14 individual events and find that the mean energy of the cosmic-ray sample is 2.9 × 1018 eV, which is significantly lower than the previous estimate. By simulating the ANITA flight, we calculate its exposure for ultra-high energy cosmic rays. We estimate for the first time the cosmic-ray flux derived only from radio observations and find agreement with measurements performed at other observatories. In addition, we find that the ANITA data set is consistent with Monte Carlo simulations for the total number of observed events and with the properties of those events.

Published
2016

30. Magnetic Trapping of Cold Bromine Atoms

Author

Rennick, C. J., Lam, J., Doherty, W. G., and Softley, T. P.

Subjects
Physics - Atomic Physics
Abstract

Magnetic trapping of bromine atoms at temperatures in the milliKelvin regime is demonstrated for the first time. The atoms are produced by photodissociation of Br$_2$ molecules in a molecular beam. The lab-frame velocity of Br atoms is controlled by the wavelength and polarization of the photodissociation laser. Careful selection of the wavelength results in one of the pair of atoms having sufficient velocity to exactly cancel that of the parent molecule, and it remains stationary in the lab frame. A trap is formed at the null point between two opposing neodymium permanent magnets. Dissociation of molecules at the field minimum results in the slowest fraction of photofragments remaining trapped. After the ballistic escape of the fastest atoms, the trapped slow atoms are only lost by elastic collisions with the chamber background gas. The measured loss rate is consistent with estimates of the total cross section for only those collisions transferring sufficient kinetic energy to overcome the trapping potential.

Published
2014
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32. Fetal growth and maternal glomerular filtration rate: A systematic review

Author

Vesterinen, HM, Johnson, PI, Atchley, DS, Sutton, P, Lam, J, Zlatnik, MG, Sen, S, and Woodruff, TJ

Subjects
Obstetrics & Reproductive Medicine, Paediatrics and Reproductive Medicine
Abstract

Objective: Glomerular filtration rate (GFR) may influence concentrations of biomarkers of exposure and their etiologic significance in observational studies of associations between environmental contaminants and fetal growth. It is unknown whether the size of a developing fetus affects maternal GFR such that a small fetus leads to reduced plasma volume expansion (PVE), reduced GFR and subsequent higher concentrations of biomarkers in maternal serum. Our objective was to answer the question: "Is there an association between fetal growth and maternal GFR in humans?"Methods: We adapted and applied the Navigation Guide systematic review methodology to assess the evidence of an association between fetal growth and GFR, either directly or indirectly via reduction in PVE.Results: We identified 35 relevant studies. We rated 31 human and two non-human observational studies as "low" quality and two experimental non-human studies as "very low" quality. We rated all three evidence streams as "inadequate". The association between fetal growth and GFR was "not classifiable" according to pre-specified definitions.Conclusions: There is currently insufficient evidence to support the plausibility of a reverse causality hypothesis for associations between exposure to environmental chemicals during pregnancy and fetal growth. Further research would be needed to confirm or disprove this hypothesis.

Published
2015

33. Accuracy of multiecho magnitude-based MRI (M-MRI) for estimation of hepatic proton density fat fraction (PDFF) in children

Author

Zand, KA, Shah, A, Heba, E, Wolfson, T, Hamilton, G, Lam, J, Chen, J, Hooker, JC, Gamst, AC, Middleton, MS, Schwimmer, JB, and Sirlin, CB

Subjects
Physical Sciences, Engineering, Medical and Health Sciences, Nuclear Medicine & Medical Imaging
Abstract

Purpose To assess accuracy of magnitude-based magnetic resonance imaging (M-MRI) in children to estimate hepatic proton density fat fraction (PDFF) using two to six echoes, with magnetic resonance spectroscopy (MRS) -measured PDFF as a reference standard. Methods This was an IRB-approved, HIPAA-compliant, single-center, cross-sectional, retrospective analysis of data collected prospectively between 2008 and 2013 in children with known or suspected nonalcoholic fatty liver disease (NAFLD). Two hundred eighty-six children (8-20 [mean 14.2±2.5] years; 182 boys) underwent same-day MRS and M-MRI. Unenhanced two-dimensional axial spoiled gradient-recalled-echo images at six echo times were obtained at 3T after a single low-flip-angle (10°) excitation with≥120-ms recovery time. Hepatic PDFF was estimated using the first two, three, four, five, and all six echoes. For each number of echoes, accuracy of M-MRI to estimate PDFF was assessed by linear regression with MRS-PDFF as reference standard. Accuracy metrics were regression intercept, slope, average bias, and R2. Results MRS-PDFF ranged from 0.2-40.4% (mean 13.1±9.8%). Using three to six echoes, regression intercept, slope, and average bias were 0.46-0.96%, 0.99-1.01, and 0.57-0.89%, respectively. Using two echoes, these values were 2.98%, 0.97, and 2.72%, respectively. R2 ranged 0.98-0.99 for all methods. Conclusion Using three to six echoes, M-MRI has high accuracy for hepatic PDFF estimation in children.

Published
2015

36. Delivery of iPS-NPCs to the stroke cavity within a hyaluronic acid matrix promotes the differentiation of transplanted cells

Author

Lam, J, Lowry, WE, Carmichael, ST, and Segura, T

Subjects
Materials, Chemical Sciences, Engineering, Physical Sciences
Abstract

Stroke is the leading cause of adult disability with ≈80% being ischemic. Stem cell transplantation has been shown to improve functional recovery. However, the overall survival and differentiation of these cells is still low. The infarct cavity is an ideal location for transplantation as it is directly adjacent to the highly plastic peri-infarct region. Direct transplantation of cells near the infarct cavity has resulted in low cell viability. Here, neural progenitor cells derived from induce pluripotent stem cells (iPS-NPC) are delivered to the infarct cavity of stroked mice encapsulated in a hyaluronic acid hydrogel matrix to protect the cells. To improve the overall viability of transplanted cells, each step of the transplantation process is optimized. Hydrogel mechanics and cell injection parameters are investigated to determine their effects on the inflammatory response of the brain and cell viability, respectively. Using parameters that balanced the desire to keep surgery invasiveness minimal and cell viability high, iPS-NPCs are transplanted to the stroke cavity of mice encapsulated in buffer or the hydrogel. While the hydrogel does not promote stem cell survival one week post-transplantation, it does promote differentiation of the neural progenitor cells to neuroblasts.

Published
2014

37. HiCal 2: An instrument designed for calibration of the ANITA experiment and for Antarctic surface reflectivity measurements

Author

Prohira, S., Novikov, A., Besson, D.Z., Ratzlaff, K., Stockham, J., Stockham, M., Clem, J.M., Young, R., Gorham, P.W., Allison, P., Banerjee, O., Batten, L., Beatty, J.J., Belov, K., Binns, W.R., Bugaev, V., Cao, P., Chen, C., Chen, P., Connolly, A., Cremonesi, L., Dailey, B., Deaconu, C., Dowkontt, P.F., Fox, B.D., Gordon, J., Hast, C., Hill, B., Hupe, R., Israel, M.H., Kowalski, J., Lam, J., Learned, J.G., Liewer, K.M., Liu, T.C., Ludwig, A., Matsuno, S., Miki, C., Mottram, M., Mulrey, K., Nam, J., Nichol, R.J., Oberla, E., Rauch, B.F., Roberts, J., Romero-Wolf, A., Rotter, B., Russell, J., Saltzberg, D., Schoorlemmer, H., Seckel, D., Stafford, S., Strutt, B., Tatem, K., Varner, G.S., Vieregg, A.G., Wissel, S.A., and Wu, F.

Published
2019
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39. Juvenile Spondyloarthritis in the Childhood Arthritis and Rheumatology Research Alliance Registry: High Biologic Use, Low Prevalence of HLA–B27, and Equal Sex Representation in Sacroiliitis

Author

Rumsey, Dax G., Lougee, Aimee, Matsouaka, Roland, Collier, David H., Schanberg, Laura E., Schenfeld, Jennifer, Shiff, Natalie J., Stoll, Matthew L., Stryker, Scott, Weiss, Pamela F., Beukelman, Timothy, Abel, N., Abulaban, K., Adams, A., Adams, M., Agbayani, R., Aiello, J., Akoghlanian, S., Alejandro, C., Allenspach, E., Alperin, R., Alpizar, M., Amarilyo, G., Ambler, W., Anderson, E., Ardoin, S., Armendariz, S., Baker, E., Balboni, I., Balevic, S., Ballenger, L., Ballinger, S., Balmuri, N., Barbar‐Smiley, F., Barillas‐Arias, L., Basiaga, M., Baszis, K., Becker, M., Bell‐Brunson, H., Beltz, E., Benham, H., Benseler, S., Bernal, W., Bigley, T., Binstadt, B., Black, C., Blakley, M., Bohnsack, J., Boland, J., Boneparth, A., Bowman, S., Bracaglia, C., Brooks, E., Brothers, M., Brown, A., Brunner, H., Buckley, M., Buckley, M., Bukulmez, H., Bullock, D., Cameron, B., Canna, S., Cannon, L., Carper, P., Cartwright, V., Cassidy, E., Cerracchio, L., Chalom, E., Chang, J., Chang‐Hoftman, A., Chauhan, V., Chira, P., Chinn, T., Chundru, K., Clairman, H., Co, D., Confair, A., Conlon, H., Connor, R., Cooper, A., Cooper, J., Cooper, S., Correll, C., Corvalan, R., Costanzo, D., Cron, R., Curiel‐Duran, L., Curington, T., Curry, M., Dalrymple, A., Davis, A., Davis, C., Davis, C., Davis, T., De Benedetti, F., De Ranieri, D., Dean, J., Dedeoglu, F., DeGuzman, M., Delnay, N., Dempsey, V., DeSantis, E., Dickson, T., Dingle, J., Donaldson, B., Dorsey, E., Dover, S., Dowling, J., Drew, J., Driest, K., Du, Q., Duarte, K., Durkee, D., Duverger, E., Dvergsten, J., Eberhard, A., Eckert, M., Ede, K., Edelheit, B., Edens, C., Edens, C., Edgerly, Y., Elder, M., Ervin, B., Fadrhonc, S., Failing, C., Fair, D., Falcon, M., Favier, L., Federici, S., Feldman, B., Fennell, J., Ferguson, I., Ferguson, P., Ferreira, B., Ferrucho, R., Fields, K., Finkel, T., Fitzgerald, M., Fleming, C., Flynn, O., Fogel, L., Fox, E., Fox, M., Franco, L., Freeman, M., Fritz, K., Froese, S., Fuhlbrigge, R., Fuller, J., George, N., Gerhold, K., Gerstbacher, D., Gilbert, M., Gillispie‐Taylor, M., Giverc, E., Godiwala, C., Goh, I., Goheer, H., Goldsmith, D., Gotschlich, E., Gotte, A., Gottlieb, B., Gracia, C., Graham, T., Grevich, S., Griffin, T., Griswold, J., Grom, A., Guevara, M., Guittar, P., Guzman, M., Hager, M., Hahn, T., Halyabar, O., Hammelev, E., Hance, M., Hanson, A., Harel, L., Haro, S., Harris, J., Harry, O., Hartigan, E., Hausmann, J., Hay, A., Hayward, K., Heiart, J., Hekl, K., Henderson, L., Henrickson, M., Hersh, A., Hickey, K., Hill, P., Hillyer, S., Hiraki, L., Hiskey, M., Hobday, P., Hoffart, C., Holland, M., Hollander, M., Hong, S., Horwitz, M., Hsu, J., Huber, A., Huggins, J., Hui‐Yuen, J., Hung, C., Huntington, J., Huttenlocher, A., Ibarra, M., Imundo, L., Inman, C., Insalaco, A., Jackson, A., Jackson, S., James, K., Janow, G., Jaquith, J., Jared, S., Johnson, N., Jones, J., Jones, J., Jones, J., Jones, K., Jones, S., Joshi, S., Jung, L., Justice, C., Justiniano, A., Karan, N., Kaufman, K., Kemp, A., Kessler, E., Khalsa, U., Kienzle, B., Kim, S., Kimura, Y., Kingsbury, D., Kitcharoensakkul, M., Klausmeier, T., Klein, K., Klein‐Gitelman, M., Kompelien, B., Kosikowski, A., Kovalick, L., Kracker, J., Kramer, S., Kremer, C., Lai, J., Lam, J., Lang, B., Lapidus, S., Lapin, B., Lasky, A., Latham, D., Lawson, E., Laxer, R., Lee, P., Lee, P., Lee, T., Lentini, L., Lerman, M., Levy, D., Li, S., Lieberman, S., Lim, L., Lin, C., Ling, N., Lingis, M., Lo, M., Lovell, D., Lowman, D., Luca, N., Lvovich, S., Madison, C., Madison, J., Magni Manzoni, S., Malla, B., Maller, J., Malloy, M., Mannion, M., Manos, C., Marques, L., Martyniuk, A., Mason, T., Mathus, S., McAllister, L., McCarthy, K., McConnell, K., McCormick, E., McCurdy, D., McCurdy Stokes, P., McGuire, S., McHale, I., McMonagle, A., McMullen‐Jackson, C., Meidan, E., Mellins, E., Mendoza, E., Mercado, R., Merritt, A., Michalowski, L., Miettunen, P., Miller, M., Milojevic, D., Mirizio, E., Misajon, E., Mitchell, M., Modica, R., Mohan, S., Moore, K., Moorthy, L., Morgan, S., Morgan Dewitt, E., Moss, C., Moussa, T., Mruk, V., Murphy, A., Muscal, E., Nadler, R., Nahal, B., Nanda, K., Nasah, N., Nassi, L., Nativ, S., Natter, M., Neely, J., Nelson, B., Newhall, L., Ng, L., Nicholas, J., Nicolai, R., Nigrovic, P., Nocton, J., Nolan, B., Oberle, E., Obispo, B., O’Brien, B., O’Brien, T., Okeke, O., Oliver, M., Olson, J., O’Neil, K., Onel, K., Orandi, A., Orlando, M., Osei‐Onomah, S., Oz, R., Pagano, E., Paller, A., Pan, N., Panupattanapong, S., Pardeo, M., Paredes, J., Parsons, A., Patel, J., Pentakota, K., Pepmueller, P., Pfeiffer, T., Phillippi, K., Pires Marafon, D., Phillippi, K., Ponder, L., Pooni, R., Prahalad, S., Pratt, S., Protopapas, S., Puplava, B., Quach, J., Quinlan‐Waters, M., Rabinovich, C., Radhakrishna, S., Rafko, J., Raisian, J., Rakestraw, A., Ramirez, C., Ramsay, E., Ramsey, S., Randell, R., Reed, A., Reed, A., Reed, A., Reid, H., Remmel, K., Repp, A., Reyes, A., Richmond, A., Riebschleger, M., Ringold, S., Riordan, M., Riskalla, M., Ritter, M., Rivas‐Chacon, R., Robinson, A., Rodela, E., Rodriquez, M., Rojas, K., Ronis, T., Rosenkranz, M., Rosolowski, B., Rothermel, H., Rothman, D., Roth‐Wojcicki, E., Rouster – Stevens, K., Rubinstein, T., Ruth, N., Saad, N., Sabbagh, S., Sacco, E., Sadun, R., Sandborg, C., Sanni, A., Santiago, L., Sarkissian, A., Savani, S., Scalzi, L., Scharnhorst, S., Schikler, K., Schlefman, A., Schmeling, H., Schmidt, K., Schmitt, E., Schneider, R., Schollaert‐Fitch, K., Schulert, G., Seay, T., Seper, C., Shalen, J., Sheets, R., Shelly, A., Shenoi, S., Shergill, K., Shirley, J., Shishov, M., Shivers, C., Silverman, E., Singer, N., Sivaraman, V., Sletten, J., Smith, A., Smith, C., Smith, J., Smith, J., Smitherman, E., Soep, J., Son, M., Spence, S., Spiegel, L., Spitznagle, J., Sran, R., Srinivasalu, H., Stapp, H., Steigerwald, K., Sterba Rakovchik, Y., Stern, S., Stevens, A., Stevens, B., Stevenson, R., Stewart, K., Stingl, C., Stokes, J., Stringer, E., Sule, S., Sumner, J., Sundel, R., Sutter, M., Syed, R., Syverson, G., Szymanski, A., Taber, S., Tal, R., Tambralli, A., Taneja, A., Tanner, T., Tapani, S., Tarshish, G., Tarvin, S., Tate, L., Taxter, A., Taylor, J., Terry, M., Tesher, M., Thatayatikom, A., Thomas, B., Tiffany, K., Ting, T., Tipp, A., Toib, D., Torok, K., Toruner, C., Tory, H., Toth, M., Tse, S., Tubwell, V., Twilt, M., Uriguen, S., Valcarcel, T., Van Mater, H., Vannoy, L., Varghese, C., Vasquez, N., Vazzana, K., Vehe, R., Veiga, K., Velez, J., Verbsky, J., Vilar, G., Volpe, N., von Scheven, E., Vora, S., Wagner, J., Wagner‐Weiner, L., Wahezi, D., Waite, H., Walker, J., Walters, H., Wampler Muskardin, T., Waqar, L., Waterfield, M., Watson, M., Watts, A., Weiser, P., Weiss, J., Wershba, E., White, A., Williams, C., Wise, A., Woo, J., Woolnough, L., Wright, T., Wu, E., Yalcindag, A., Yee, M., Yen, E., Yeung, R., Yomogida, K., Yu, Q., Zapata, R., Zartoshti, A., Zeft, A., Zeft, R., Zhang, Y., Zhao, Y., Zhu, A., and Zic, C.

Published
2021
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41. Improvement in Multi-Domain Patient-Reported Outcome Scores With Mavacamten Treatment in Obstructive Hypertrophic Cardiomyopathy: Insights From the VALOR-HCM Study

Author

Desai, M., primary, Spertus, J., additional, Owens, A., additional, Geske, J., additional, Wolski, K., additional, Saberi, S., additional, Wang, A., additional, Sherrid, M., additional, Cremer, P., additional, Lakdawala, N., additional, Fifer, M., additional, Fermin, D., additional, Naidu, S., additional, Smedira, N., additional, Schaff, H., additional, Balasubramanyam, A., additional, Zhong, Y., additional, Lam, J., additional, Wyrwich, K., additional, Lampl, K., additional, and Nissen, S., additional

Published
2023
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45. Dynamic tunable notch filters for the Antarctic Impulsive Transient Antenna (ANITA)

Author

Allison, P., Banerjee, O., Beatty, J.J., Connolly, A., Deaconu, C., Gordon, J., Gorham, P.W., Kovacevich, M., Miki, C., Oberla, E., Roberts, J., Rotter, B., Stafford, S., Tatem, K., Batten, L., Belov, K., Besson, D.Z., Binns, W.R., Bugaev, V., Cao, P., Chen, C., Chen, P., Chen, Y., Clem, J.M., Cremonesi, L., Dailey, B., Dowkontt, P.F., Hsu, S., Huang, J., Hupe, R., Israel, M.H., Kowalski, J., Lam, J., Learned, J.G., Liewer, K.M., Liu, T.C., Ludwig, A.B., Matsuno, S., Mulrey, K., Nam, J., Nichol, R.J., Novikov, A., Prohira, S., Rauch, B.F., Ripa, J., Romero-Wolf, A., Russell, J., Saltzberg, D., Seckel, D., Shiao, J., Stockham, J., Stockham, M., Strutt, B., Varner, G.S., Vieregg, A.G., Wang, S., Wissel, S.A., Wu, F., and Young, R.

Published
2018
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50. Scaling and the Metal-Insulator Transition in Si/SiGe Quantum Wells

Author

Lam, J., D'Iorio, M., Brown, D., and Lafontaine, H.

Subjects
Condensed Matter - Mesoscale and Nanoscale Physics
Abstract

The existence of a metal-insulator transition at zero magnetic field in two- dimensional electron systems has recently been confirmed in high mobility Si-MOSFETs. In this work, the temperature dependence of the resistivity of gated Si/SiGe/Si quantum well structures has revealed a similar metal- insulator transition as a function of carrier density at zero magnetic field. We also report evidence for a Coulomb gap in the temperature dependence of the resistivity of the dilute 2D hole gas confined in a SiGe quantum well. In addition, the resistivity in the insulating phase scales with a single parameter, and is sample independent. These results are consistent with the occurrence of a metal-insulator transition at zero magnetic field in SiGe square quantum wells driven by strong hole-hole interactions., Comment: 3 pages, 3 figures, LaTeX

Published
1997
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