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361 results on '"Mace, E."'

1. Cosmogenic production of $^{39}$Ar and $^{37}$Ar in argon

Author

Saldanha, R., Back, H. O., Tsang, R. H. M., Alexander, T., Elliott, S. R., Ferrara, S., Mace, E., Overman, C., and Zalavadia, M.

Subjects
Nuclear Experiment, Astrophysics - Instrumentation and Methods for Astrophysics, Physics - Instrumentation and Detectors
Abstract

We have experimentally determined the production rate of $^{39}$Ar and $^{37}$Ar from cosmic ray neutron interactions in argon at sea level. Understanding these production rates is important for argon-based dark matter experiments that plan to utilize argon extracted from deep underground because it is imperative to know what the ingrowth of $^{39}$Ar will be during the production, transport, and storage of the underground argon. These measurements also allow for the prediction of $^{39}$Ar and $^{37}$Ar concentrations in the atmosphere which can be used to determine the presence of other sources of these isotopes. Through controlled irradiation with a neutron beam that mimics the cosmic ray neutron spectrum, followed by direct counting of $^{39}$Ar and $^{37}$Ar decays with sensitive ultra-low background proportional counters, we determined that the production rate from cosmic ray neutrons at sea-level is expected to be $(759 \pm 128)$ atoms/kg$_\text{Ar}$/day for $^{39}$Ar, and $(51.0 \pm 7.4)$ atoms/kg$_\text{Ar}$/day for $^{37}$Ar. We also performed a survey of the alternate production mechanisms based on the state-of-knowledge of the associated cross-sections to obtain a total sea-level cosmic ray production rate of $(1048 \pm 133)$ atoms/kg$_\text{Ar}$/day for $^{39}$Ar, $(56.7 \pm 7.5)$ atoms/kg$_\text{Ar}$/day for $^{37}$Ar in underground argon, and $(92 \pm 13)$ atoms/kg$_\text{Ar}$/day for $^{37}$Ar in atmospheric argon., Comment: 13 pages, 9 figures, 6 tables; Minor updates to systematic uncertainty evaluation, formatting

Published
2019
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3. Development of a low-level Ar-37 calibration standard

Author

Williams, R. M., Aalseth, C. E., Bowyer, T. W., Day, A. R., Fuller, E. S., Haas, D. A., Hayes, J. C., Hoppe, E. W., Humble, P. H., Keillor, M. E., LaFerriere, B. D., Mace, E. K., McIntyre, J. I., Miley, H. S., Myers, A. W., Orrell, J. L., Overman, C. T., Panisko, M. E., and Seifert, A.

Subjects
Physics - Instrumentation and Detectors
Abstract

Argon-37 is an environmental signature of an underground nuclear explosion. Producing and quantifying low-level Ar-37 standards is an important step in the development of sensitive field measurement instruments. This paper describes progress at Pacific Northwest National Laboratory in developing a process to generate and quantify low-level Ar-37 standards, which can be used to calibrate sensitive field systems at activities consistent with soil background levels. This paper presents a discussion of the measurement analysis, along with assumptions and uncertainty estimates., Comment: Proceedings of the 20th International Conference on Radionuclide Metrology and its Applications 8-11 June 2015, Vienna, Austria

Published
2016
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6. Effects of fast and thermal neutron irradiation on Ga-polar and N-polar GaN diodes.

Author

Mirkhosravi, F., Rashidi, A., Elshafiey, A. T., Gallagher, J., Abedi, Z., Ahn, K., Lintereur, A., Mace, E. K., Scarpulla, M. A., and Feezell, D.

Subjects
NEUTRON irradiation, FAST neutrons, THERMAL neutrons, RADIATION tolerance, SCHOTTKY barrier diodes, DIODES, PARTICLE accelerators
Abstract

Studies of the radiation tolerance and electrical behavior of gallium nitride (GaN) based devices are important for the next generation of high-power and high-voltage electronics that may be subjected to harsh environments such as nuclear reactor and fusion facilities, particle accelerators, and post-denotation environments. In this work, we study the behavior of Ga-polar and N-polar GaN Schottky diodes before and after exposure to fast and thermal + fast neutrons. Temperature-dependent current–voltage (I–V) and circular transmission line method (CTLM) measurements were used to study the electrical characteristics. A strong reduction in reverse leakage current and an increase in differential resistance in forward bias were observed after neutron irradiation. Thermionic emission (TE), Frenkel–Poole (FP) emission, and Fowler–Nordheim (FN) tunneling models were used to explain the forward and reverse I–V characteristics pre- and post-irradiation. The study confirms that Ga-polar and N-polar GaN Schottky diodes exhibit different electrical responses to fast and thermal neutron irradiations. The reverse bias characteristics of N-polar diodes are less affected after the fast neutron irradiation compared to Ga-polar diodes, while in the forward bias region, the electrical behavior after fast and thermal neutron irradiations is similar in Ga-polar and N-polar diodes. The results indicate that the role of orientation should be considered in the design of GaN-based radiation-tolerant electronics. [ABSTRACT FROM AUTHOR]

Published
2023
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7. Measurement of 37Ar to support technology for On-site Inspection under the Comprehensive Nuclear-Test-Ban Treaty

Author

Aalseth, C. E., Day, A. R., Haas, D. A., Hoppe, E. W., Hyronimus, B. J., Keillor, M. E., Mace, E. K., Orrell, J. L., Seifert, A., and Woods, V. T.

Subjects
Nuclear Experiment
Abstract

On-Site Inspection (OSI) is a key component of the verification regime for the Comprehensive Nuclear-Test-Ban Treaty (CTBT). Measurements of radionuclide isotopes created by an underground nuclear explosion are a valuable signature of a Treaty violation. Argon-37 is produced from neutron interaction with calcium in soil, 40Ca(n,{\alpha})37Ar. For OSI, the 35-day half-life of 37Ar provides both high specific activity and sufficient time for completion of an inspection before decay limits sensitivity. This paper presents a low-background internal-source gas proportional counter with an 37Ar measurement sensitivity level equivalent to 45.1 mBq/SCM in whole air., Comment: Submitted to Nucl. Instru. Meth. A for peer review a part of the proceedings of the 2010 Symposium on Radiation Measurements and Applications (SORMA XII), May 24-28, 2010 at the University of Michigan, Ann Arbor, Michigan, USA. Document details: 5 pages, 4 figures

Published
2010
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13. Differences in electrical responses and recovery of GaN p+n diodes on sapphire and freestanding GaN subjected to high dose 60Co gamma-ray irradiation.

Author

Ahn, K., Ooi, Y. K., Mirkhosravi, F., Gallagher, J., Lintereur, A., Feezell, D., Mace, E. K., and Scarpulla, M. A.

Subjects
GALLIUM nitride, SAPPHIRES, DIODES, GAMMA rays, OHMIC contacts, POINT defects, RADIATION damage
Abstract

We investigate the effects of high-rate and high total doses of 60Co gamma rays on the current–voltage (IV) characteristics of GaN p+n diodes grown by metal-organic chemical vapor phase epitaxy on Ga-face (0001) sapphire and hydride vapor phase epitaxy freestanding GaN substrates. We show that diodes grown on sapphire undergo more permanent changes upon irradiation at doses up to 3900 kGy than those grown on freestanding GaN. By combining diode and circular transfer length method measurements, we show that the p-type contact interface and adjacent p++ Mg-doped layer are sensitive to irradiation. In initial experiments, diodes grown on sapphire exhibited p-type contacts with Schottky characteristics, while those on freestanding GaN were Ohmic. Serendipitously, we identified and subsequently irradiated a freestanding sample with a pre-irradiation spatial gradient of p-contact Schottky vs Ohmic behavior across the die. This sample allowed the root cause of induced change to be identified as differences in the p++ contacting layer. We show that the p-type contact's pre-irradiation Schottky behavior is predictive of diodes' IV characteristics changing significantly upon gamma-ray irradiation. Further, we observe that the IV curves of diodes on freestanding GaN recover fully over several weeks at room temperature to be indistinguishable from pre-irradiation. IV curves from diodes on sapphire do not fully recover; we thus hypothesize that interactions between radiation-induced point defects and threading dislocations affect the evolution of radiation damage. [ABSTRACT FROM AUTHOR]

Published
2021
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15. Noble gas migration experiment to support the detection of underground nuclear explosions

Author

Olsen, K. B., Kirkham, R. R., Woods, V. T., Haas, D. H., Hayes, J. C., Bowyer, T. W., Mendoza, D. P., Lowrey, J. D., Lukins, C. D., Suarez, R. D., Humble, P. H., Ellefson, M. D., Ripplinger, M. D., Zhong, L., Mitroshkov, A. V., Aalseth, C. E., Prinke, A. M., Mace, E. K., McIntyre, J. I., Stewart, T. L., Mackley, R. D., Milbrath, B. D., Emer, D. F., and Biegalski, S. R.

Published
2016
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24. Genomic resources in plant breeding for sustainable agriculture

Author

Thudi, M., Palakurthi, R., Schnable, J.C., Chitikineni, A., Dreisigacker, S., Mace, E., Srivastava, R.K., Satyavathi, C.T., Odeny, D., Tiwari, V.K., Lam, H-M, Hong, Y.B., Singh, V.K., Li, G., Xu, Y., Chen, X., Kaila, S., Nguyen, H., Sivasankar, S., Jackson, S.A., Close, T.J., Shubo, W., Varshney, R.K., Thudi, M., Palakurthi, R., Schnable, J.C., Chitikineni, A., Dreisigacker, S., Mace, E., Srivastava, R.K., Satyavathi, C.T., Odeny, D., Tiwari, V.K., Lam, H-M, Hong, Y.B., Singh, V.K., Li, G., Xu, Y., Chen, X., Kaila, S., Nguyen, H., Sivasankar, S., Jackson, S.A., Close, T.J., Shubo, W., and Varshney, R.K.

Abstract

Climate change during the last 40 years has had a serious impact on agriculture and threatens global food and nutritional security. From over half a million plant species, cereals and legumes are the most important for food and nutritional security. Although systematic plant breeding has a relatively short history, conventional breeding coupled with advances in technology and crop management strategies has increased crop yields by 56 % globally between 1965−85, referred to as the Green Revolution. Nevertheless, increased demand for food, feed, fiber, and fuel necessitates the need to break existing yield barriers in many crop plants. In the first decade of the 21st century we witnessed rapid discovery, transformative technological development and declining costs of genomics technologies. In the second decade, the field turned towards making sense of the vast amount of genomic information and subsequently moved towards accurately predicting gene-to-phenotype associations and tailoring plants for climate resilience and global food security. In this review we focus on genomic resources, genome and germplasm sequencing, sequencing-based trait mapping, and genomics-assisted breeding approaches aimed at developing biotic stress resistant, abiotic stress tolerant and high nutrition varieties in six major cereals (rice, maize, wheat, barley, sorghum and pearl millet), and six major legumes (soybean, groundnut, cowpea, common bean, chickpea and pigeonpea). We further provide a perspective and way forward to use genomic breeding approaches including marker-assisted selection, marker-assisted backcrossing, haplotype based breeding and genomic prediction approaches coupled with machine learning and artificial intelligence, to speed breeding approaches. The overall goal is to accelerate genetic gains and deliver climate resilient and high nutrition crop varieties for sustainable agriculture.

Published
2021

44. A novel disorder involving dyshematopoiesis, inflammation, and HLH due to aberrant CDC42 function

Author

Lam, M. T., Coppola, S., Krumbach, O. H. F., Prencipe, G., Insalaco, A., Cifaldi, C., Brigida, I., Zara, E., Scala, S., Di Cesare, S., Martinelli, S., Di Rocco, M., Pascarella, A., Niceta, M., Pantaleoni, F., Ciolfi, A., Netter, P., Carisey, A. F., Diehl, M., Akbarzadeh, M., Cont, F., Merli, P., Pastore, A., Mortera, S. L., Camerini, S., Farina, L., Buchholzer, M., Pannone, L., Cao, T. N., Coban-Akdemir, Z. H., Jhangiani, S. N., Muzny, D. M., Gibbs, R. A., Basso-Ricci, L., Chiriaco, M., Dvorsky, R., Putignani, L., Carsetti, R., Janning, P., Stray-Pedersen, A., Erichsen, H. C., Horne, A. C., Bryceson, Y. T., Torralba-Raga, L., Ramme, K., Rosti, V., Bracaglia, C., Messia, V., Palma, P., Finocchi, A., Locatelli, Franco, Chinn, I. K., Lupski, J. R., Mace, E. M., Cancrini, C., Aiuti, A., Ahmadian, M. R., Orange, J. S., De Benedetti, F., Tartaglia, M., Locatelli F. (ORCID:0000-0002-7976-3654), Lam, M. T., Coppola, S., Krumbach, O. H. F., Prencipe, G., Insalaco, A., Cifaldi, C., Brigida, I., Zara, E., Scala, S., Di Cesare, S., Martinelli, S., Di Rocco, M., Pascarella, A., Niceta, M., Pantaleoni, F., Ciolfi, A., Netter, P., Carisey, A. F., Diehl, M., Akbarzadeh, M., Cont, F., Merli, P., Pastore, A., Mortera, S. L., Camerini, S., Farina, L., Buchholzer, M., Pannone, L., Cao, T. N., Coban-Akdemir, Z. H., Jhangiani, S. N., Muzny, D. M., Gibbs, R. A., Basso-Ricci, L., Chiriaco, M., Dvorsky, R., Putignani, L., Carsetti, R., Janning, P., Stray-Pedersen, A., Erichsen, H. C., Horne, A. C., Bryceson, Y. T., Torralba-Raga, L., Ramme, K., Rosti, V., Bracaglia, C., Messia, V., Palma, P., Finocchi, A., Locatelli, Franco, Chinn, I. K., Lupski, J. R., Mace, E. M., Cancrini, C., Aiuti, A., Ahmadian, M. R., Orange, J. S., De Benedetti, F., Tartaglia, M., and Locatelli F. (ORCID:0000-0002-7976-3654)

Abstract

Hemophagocytic lymphohistiocytosis (HLH) is characterized by immune dysregulation due to inadequate restraint of overactivated immune cells and is associated with a variable clinical spectrum having overlap with more common pathophysiologies. HLH is difficult to diagnose and can be part of inflammatory syndromes. Here, we identify a novel hematological/autoinflammatory condition (NOCARH syndrome) in four unrelated patients with superimposable features, including neonatal-onset cytopenia with dyshematopoiesis, autoinflammation, rash, and HLH. Patients shared the same de novo CDC42 mutation (Chr1:22417990C>T, p.R186C) and altered hematopoietic compartment, immune dysregulation, and inflammation. CDC42 mutations had been associated with syndromic neurodevelopmental disorders. In vitro and in vivo assays documented unique effects of p.R186C on CDC42 localization and function, correlating with the distinctiveness of the trait. Emapalumab was critical to the survival of one patient, who underwent successful bone marrow transplantation. Early recognition of the disorder and establishment of treatment followed by bone marrow transplant are important to survival.

Published
2019

45. Measurements of the emanation of 37Ar and 39Ar from irradiated rocks and powders.

Author

Johnson, C., Lowrey, J. D., Alexander, T., Mace, E., and Prinke, A.

Subjects
NEUTRONS, RADIOISOTOPES, GOVERNMENT laboratories, ARGON isotopes, POWDERS, MEASUREMENT
Abstract

The emanation of radionuclides has been highlighted as a known source of uncertainty in the estimation of radionuclide source signatures from underground nuclear tests and other nuclear activities, particularly in the case of activation products. A system was developed at Pacific Northwest National Laboratory to quantify the emanation of argon from two powders and five rock types ranging in particle size from powder to small rocks. Samples were neutron irradiated and the percent emanation of 37Ar was measured to range between 0.3 and 25%. Measurements were also made of the 39Ar emanation for four of these materials and was found to be consistently lower than that of 37Ar. [ABSTRACT FROM AUTHOR]

Published
2021
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46. Cosmogenic production of Ar39 and Ar37 in argon

Author

Saldanha, R., primary, Back, H. O., additional, Tsang, R. H. M., additional, Alexander, T., additional, Elliott, S. R., additional, Ferrara, S., additional, Mace, E., additional, Overman, C., additional, and Zalavadia, M., additional

Published
2019
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47. VERNALIZATION1 Modulates Root System Architecture in Wheat and Barley

Author

Voss-Fels, K. P., Robinson, H., Mudge, S. R., Richard, C., Newman, S., Wittkop, B., Stahl, A., Friedt, W., Frisch, M., Gabur, I., Miller-Cooper, A., Campbell, B. C., Kelly, Alison M., Fox, G., Christopher, J., Christopher, Mandy, Chenu, K., Franckowiak, J., Mace, E. S., Borrell, A. K., Eagles, H., Jordan, D. R., Botella, J. R., Hammer, G., Godwin, I. D., Trevaskis, B., Snowdon, R. J., Hickey, L. T., Voss-Fels, K. P., Robinson, H., Mudge, S. R., Richard, C., Newman, S., Wittkop, B., Stahl, A., Friedt, W., Frisch, M., Gabur, I., Miller-Cooper, A., Campbell, B. C., Kelly, Alison M., Fox, G., Christopher, J., Christopher, Mandy, Chenu, K., Franckowiak, J., Mace, E. S., Borrell, A. K., Eagles, H., Jordan, D. R., Botella, J. R., Hammer, G., Godwin, I. D., Trevaskis, B., Snowdon, R. J., and Hickey, L. T.

Published
2018

49. Adapting cereals to drought: genetic and management solutions.

Author

Borrell, A.K., George-Jaeggli, B., van Oosterom, E. J., Mace, E., Jordan, D., Kassahun, B., Menamo, T.M., Vadezm, V., Talwar, H., Christopher, J., Chenu, K., Richard, C., Robinson, H., Hickey, L. T., Nagothu, S., Hammer, G., Borrell, A.K., George-Jaeggli, B., van Oosterom, E. J., Mace, E., Jordan, D., Kassahun, B., Menamo, T.M., Vadezm, V., Talwar, H., Christopher, J., Chenu, K., Richard, C., Robinson, H., Hickey, L. T., Nagothu, S., and Hammer, G.

Abstract

Adapting crops to drought requires genetic and management solutions. There are many possible management systems (e.g. combinations of planting dates, fertilizers, irrigation, row spacing, population, cropping systems) and many possible genotypes to combat drought. The challenge is to identify favourable combinations of genotypes and management practices in a complex system. Examples of genetic (stay-green in sorghum & wheat) and management (water-saving strategies in rice) solutions are presented.

Published
2017

50. Erratum: SorGSD: a sorghum genome SNP database (Biotechnology for Biofuels (2016) 9:6 DOI: 10.1186/s13068-015-0415-8)

Author

Luo, H., Zhao, W., Wang, Y., Xia, Y., Wu, X., Zhang, L., Tang, B., Zhu, J., Fang, L., Du, Z., Bekele, W. A., Tai, S., Jordan, D. R., Godwin, I. D., Snowdon, R. J., Mace, E. S., Luo, J., Jing, H. C., Luo, H., Zhao, W., Wang, Y., Xia, Y., Wu, X., Zhang, L., Tang, B., Zhu, J., Fang, L., Du, Z., Bekele, W. A., Tai, S., Jordan, D. R., Godwin, I. D., Snowdon, R. J., Mace, E. S., Luo, J., and Jing, H. C.

Published
2016

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