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310 results on '"Erikson L"'

1. A direct measurement of the 17O(a,g)21Ne reaction in inverse kinematics and its impact on heavy element production

Author

Taggart, M. P., Akers, C., Laird, A. M., Hager, U., Ruiz, C., Hutcheon, D. A., Bentley, M. A., Brown, J. R., Buchmann, L., Chen, A. A., Chen, J., Chipps, K. A., Choplin, A., D'Auria, J. M., Davids, B., Davis, C., Diget, C. Aa., Erikson, L., Fallis, J., Fox, S. P., Frischknecht, U., Fulton, B. R., Galinski, N., Greife, U., Hirschi, R., Howell, D., Martin, L., Mountford, D., Murphy, A. St. J., Ottewell, D., Pignatari, M., Reeve, S., Ruprecht, G., Sjue, S., Veloce, L., and Williams, M.

Subjects
Nuclear Experiment
Abstract

During the slow neutron capture process in massive stars, reactions on light elements can both produce and absorb neutrons thereby influencing the final heavy element abundances. At low metallicities, the high neutron capture rate of 16-O can inhibit s-process nucleosynthesis unless the neutrons are recycled via the 17O(a,n)20Ne reaction. The efficiency of this neutron recycling is determined by competition between the 17O(a,n)20Ne and 17O(a,g)21Ne reactions. While some experimental data are available on the former reaction, no data exist for the radiative capture channel at the relevant astrophysical energies. The 17O(a,g)21Ne reaction has been studied directly using the DRAGON recoil separator at the TRIUMF Laboratory. The reaction cross section has been determined at energies between 0.6 and 1.6 MeV Ecm, reaching into the Gamow window for core helium burning for the first time. Resonance strengths for resonances at 0.63, 0.721, 0.81 and 1.122 MeV Ecm have been extracted. The experimentally based reaction rate calculated represents a lower limit, but suggests that significant s-process nucleosynthesis occurs in low metallicity massive stars., Comment: 7 pages, 5 figures

Published
2019
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2. Robustness and uncertainties in global multivariate wind-wave climate projections

Author

Morim, J, Hemer, M, Wang, XL, Cartwright, N, Trenham, C, Semedo, A, Young, I, Bricheno, L, Camus, P, Casas-Prat, M, Erikson, L, Mentaschi, L, Mori, N, Shimura, T, Timmermans, B, Aarnes, O, Breivik, Ø, Behrens, A, Dobrynin, M, Menendez, M, Staneva, J, Wehner, M, Wolf, J, Kamranzad, B, Webb, A, Stopa, J, and Andutta, F

Subjects
Atmospheric Sciences, Physical Geography and Environmental Geoscience, Environmental Science and Management
Abstract

Understanding climate-driven impacts on the multivariate global wind-wave climate is paramount to effective offshore/coastal climate adaptation planning. However, the use of single-method ensembles and variations arising from different methodologies has resulted in unquantified uncertainty amongst existing global wave climate projections. Here, assessing the first coherent, community-driven, multi-method ensemble of global wave climate projections, we demonstrate widespread ocean regions with robust changes in annual mean significant wave height and mean wave period of 5–15% and shifts in mean wave direction of 5–15°, under a high-emission scenario. Approximately 50% of the world’s coastline is at risk from wave climate change, with ~40% revealing robust changes in at least two variables. Furthermore, we find that uncertainty in current projections is dominated by climate model-driven uncertainty, and that single-method modelling studies are unable to capture up to ~50% of the total associated uncertainty.

Published
2019

6. Dunbar Syndrome

Author

Angela Barnes, Abdul-Rahman Abualruz, and John Erikson L. Yap

Subjects
Diseases of the digestive system. Gastroenterology, RC799-869
Published
2023
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7. Tropical or extratropical cyclones: what drives the compound flood hazard, impact, and risk for the United States Southeast Atlantic coast?

Author

Nederhoff, K. Leijnse, T. W. B. Parker, K. Thomas, J. O’Neill, A. van Ormondt, M. McCall, R. Erikson, L. Barnard, P. L. Foxgrover, A. Klessens, W. Nadal-Caraballo, N. C. Massey, T. C. and Nederhoff, K. Leijnse, T. W. B. Parker, K. Thomas, J. O’Neill, A. van Ormondt, M. McCall, R. Erikson, L. Barnard, P. L. Foxgrover, A. Klessens, W. Nadal-Caraballo, N. C. Massey, T. C.

Abstract

Subtropical coastlines are impacted by both tropical and extratropical cyclones. While both may lead to substantial damage to coastal communities, it is difficult to determine the contribution of tropical cyclones to coastal flooding relative to that of extratropical cyclones. We conduct a large-scale flood hazard and impact assessment across the subtropical Southeast Atlantic Coast of the United States, from Virginia to Florida, including different flood hazards. The physics-based hydrodynamic modeling skillfully reproduces coastal water levels based on a comprehensive validation of tides, almost two hundred historical storms, and an in-depth hindcast of Hurricane Florence. We show that yearly flood impacts are two times as likely to be driven by extratropical than tropical cyclones. On the other hand, tropical cyclones are 30 times more likely to affect people during rarer 100-year events than extratropical cyclones and contribute to more than half of the regional flood risk. With increasing sea levels, more areas will be flooded, regardless of whether flooding is driven by tropical or extratropical cyclones. Most of the absolute flood risk is contained in the greater Miami metropolitan area. However, several less populous counties have the highest relative risks. The results of this study provide critical information for understanding the source and frequency of compound flooding across the Southeast Atlantic Coast of the United States.

Published
2024
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9. Direct reaction measurements with a 132Sn radioactive ion beam

Author

Jones, K. L., Adekola, A. S., Bardayan, D. W., Blackmon, J. C., Chae, K. Y., Chipps, K. A., Cizewski, J. A., Erikson, L., Harlin, C., Hatarik, R., Kapler, R., Kozub, R. L., Liang, J. F., Livesay, R., Ma, Z., Moazen, B. H., Nesaraja, C. D., Nunes, F. M., Pain, S. D., Patterson, N. P., Shapira, D., Shriner Jr, J. F., Smith, M. S., Swan, T. P., and Thomas, J. S.

Subjects
Nuclear Experiment
Abstract

The (d,p) neutron transfer and (d,d) elastic scattering reactions were measured in inverse kinematics using a radioactive ion beam of 132Sn at 630 MeV. The elastic scattering data were taken in a region where Rutherford scattering dominated the reaction, and nuclear effects account for less than 8% of the cross section. The magnitude of the nuclear effects was found to be independent of the optical potential used, allowing the transfer data to be normalized in a reliable manner. The neutron-transfer reaction populated a previously unmeasured state at 1363 keV, which is most likely the single-particle 3p1/2 state expected above the N=82 shell closure. The data were analyzed using finite range adiabatic wave calculations and the results compared with the previous analysis using the distorted wave Born approximation. Angular distributions for the ground and first excited states are consistent with the previous tentative spin and parity assignments. Spectroscopic factors extracted from the differential cross sections are similar to those found for the one neutron states beyond the benchmark doubly-magic nucleus 208Pb., Comment: 22 pages, 7 figures

Published
2011
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10. The magic nature of 132Sn explored through the single-particle states of 133Sn

Author

Jones, K. L., Adekola, A. S., Bardayan, D. W., Blackmon, J. C., Chae, K. Y., Chipps, K. A., Cizewski, J. A., Erikson, L., Harlin, C., Hatarik, R., Kapler, R., Kozub, R. L., Liang, J. F., Livesay, R., Ma, Z., Moazen, B. H., Nesaraja, C. D., Nunes, F. M., Pain, S. D., Patterson, N. P., Shapira, D., Shriner Jr, J. F., Smith, M. S., Swan, T. P., and Thomas, J. S.

Subjects
Nuclear Experiment
Abstract

Atomic nuclei have a shell structure where nuclei with 'magic numbers' of neutrons and protons are analogous to the noble gases in atomic physics. Only ten nuclei with the standard magic numbers of both neutrons and protons have so far been observed. The nuclear shell model is founded on the precept that neutrons and protons can move as independent particles in orbitals with discrete quantum numbers, subject to a mean field generated by all the other nucleons. Knowledge of the properties of single-particle states outside nuclear shell closures in exotic nuclei is important for a fundamental understanding of nuclear structure and nucleosynthesis (for example the r-process, which is responsible for the production of about half of the heavy elements). However, as a result of their short lifetimes, there is a paucity of knowledge about the nature of single-particle states outside exotic doubly magic nuclei. Here we measure the single-particle character of the levels in 133Sn that lie outside the double shell closure present at the short-lived nucleus 132Sn. We use an inverse kinematics technique that involves the transfer of a single nucleon to the nucleus. The purity of the measured single-particle states clearly illustrates the magic nature of 132Sn., Comment: 19 pages, 5 figures and 4 tables

Published
2010
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11. Global Projections of Storm Surges Using High-Resolution CMIP6 Climate Models

Author

Muis, S. Aerts, J. C. J. H. Á. Antolínez, J. A. Dullaart, J. C. Duong, T. M. Erikson, L. Haarsma, R. J. Apecechea, M. I. Mengel, M. Le Bars, D. O’Neill, A. Ranasinghe, R. Roberts, M. J. Verlaan, M. Ward, P. J. Yan, K. and Muis, S. Aerts, J. C. J. H. Á. Antolínez, J. A. Dullaart, J. C. Duong, T. M. Erikson, L. Haarsma, R. J. Apecechea, M. I. Mengel, M. Le Bars, D. O’Neill, A. Ranasinghe, R. Roberts, M. J. Verlaan, M. Ward, P. J. Yan, K.

Abstract

In the coming decades, coastal flooding will become more frequent due to sea-level rise and potential changes in storms. To produce global storm surge projections from 1950 to 2050, we force the Global Tide and Surge Model with a ∼25-km resolution climate model ensemble from the Coupled Model Intercomparison Project Phase 6 High Resolution Model Intercomparison Project (HighResMIP). This is the first time that such a high-resolution ensemble is used to assess changes in future storm surges across the globe. We validate the present epoch (1985–2014) against the ERA5 climate reanalysis, which shows a good overall agreement. However, there is a clear spatial bias with generally a positive bias in coastal areas along semi-enclosed seas and negative bias in equatorial regions. Comparing the future epoch (2021–2050) against the historical epoch (1951–1980), we project ensemble-median changes up to 0.1 (or 20%) in the 1 in 10-year storm surge levels. These changes are not uniform across the globe with decreases along the coast of Mediterranean and northern Africa and southern Australia and increases along the south coast of Australia and Alaska. There are also increases along (parts) of the coasts of northern Caribbean, eastern Africa, China and the Korean peninsula, but with less agreement among the HighResMIP ensemble. Information resulting from this study can be used to inform broad-scale assessment of coastal impacts under future climate change.

Published
2023
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13. Dunbar Syndrome

Author

Barnes, Angela, primary, Abualruz, Abdul-Rahman, additional, and Yap, John Erikson L., additional

Published
2023
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15. Advanced Quantitative Precipitation Information: Improving Monitoring and Forecasts of Precipitation, Streamflow, and Coastal Flooding in the San Francisco Bay Area

Author

Cifelli, Rob, primary, Chandrasekar, V., additional, Herdman, L., additional, Turner, D. D., additional, White, A. B., additional, Alcott, T. I., additional, Anderson, M., additional, Barnard, P., additional, Biswas, S. K., additional, Boucher, M., additional, Bytheway, J., additional, Chen, H., additional, Cutler, H., additional, English, J. M., additional, Erikson, L., additional, Junyent, F., additional, Gottas, D. J., additional, Jasperse, J., additional, Johnson, L. E., additional, Krebs, J., additional, van de Lindt, J., additional, Kim, J., additional, Leon, M., additional, Ma, Y., additional, Marquis, M., additional, Moninger, W., additional, Pratt, G., additional, Radhakrishnan, C., additional, Shields, M., additional, Spaulding, J., additional, Tehranirad, B., additional, and Webb, R., additional

Published
2022
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50. Tokyo Guidelines (TG18) for Acute Cholangitis Provide Improved Specificity and Accuracy Compared to Fellow Assessment

Author

Amit, Hudgi, Anabel L, Cartelle, Amr, Ahmed, Ahmad, Alkaddour, Carlos, Palacio, Kenneth J, Vega, and John Erikson L, Yap

Subjects
General Engineering
Abstract

Background Acute cholangitis results in significant mortality unless treated promptly. The diagnostic grading criteria of the 2018 Tokyo Guidelines (TG18) are used worldwide as the standard for acute cholangitis (AC) management but validation in clinical practice is required. Aim Use of the Tokyo 2018 (TG18) guidelines in improving the diagnostic accuracy and early detection of AC compared to fellow clinical assessment. Methods A retrospective review of patient records from 1/2010-9/2019 seen at Augusta University - Medical College of Georgia with the International Classification of Diseases, Ninth Revision (ICD-9) code "cholangitis" and/or ICD-10 codes "acute cholangitis, other cholangitis, and calculus of bile duct with cholangitis" was performed. Inclusion criteria were gastroenterology inpatient consult fellow evaluation and clinical diagnosis of AC. A definitive diagnosis of AC was determined following endoscopic retrograde cholangiopancreatography (ERCP). TG18 scoring for AC was then performed, categorized as either diagnostic/non-diagnostic, and compared to fellow clinical assessments following definitive diagnosis post-ERCP. Data were analyzed with chi-square testing. Results Two hundred six patients were identified using ICD codes. Ninety-one met inclusion criteria and were analyzed. The mean patient age of the overall group was 67 years old (standard deviation of 13.3 years) with males comprising 69% and non-Hispanic white 56% of the study group. TG18 criteria assessment had a sensitivity of 86% and specificity of 63% for patients with AC post ERCP (p0.05). TG18 accuracy was 81%. In comparison, fellow clinical suspicion had a sensitivity of 90.3% and specificity of 0% (NS). Fellow accuracy was 71%. No difference in fellows' diagnosis of suspected AC was noted based on the training year. Conclusion Application of the TG18 criteria for AC reduces the false positive rate and improves diagnostic accuracy, thus decreasing costs along with avoiding unnecessary ERCPs with associated complications.

Published
2022
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