Search

Your search keyword '"D. J. Stewart"' showing total 22 results
Start Over Author "D. J. Stewart" Language english
22 results on '"D. J. Stewart"'

1. Upper limit on the chiral magnetic effect in isobar collisions at the Relativistic Heavy-Ion Collider

Author

M. I. Abdulhamid, B. E. Aboona, J. Adam, J. R. Adams, G. Agakishiev, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, A. Aitbaev, I. Alekseev, E. Alpatov, A. Aparin, S. Aslam, J. Atchison, G. S. Averichev, V. Bairathi, J. G. Ball Cap, K. Barish, P. Bhagat, A. Bhasin, S. Bhatta, S. R. Bhosale, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, C. Broodo, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, G. Dale-Gau, A. Das, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, A. Dhamija, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, T. Gao, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, A. Hamed, Y. Han, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, D. Keane, A. Kechechyan, A. Khanal, A. Kiselev, A. G. Knospe, H. S. Ko, L. Kochenda, A. A. Korobitsin, A. Yu. Kraeva, P. Kravtsov, L. Kumar, M. C. Labonte, R. Lacey, J. M. Landgraf, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, D. Li, H-S. Li, H. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, T. Lin, Y. Lin, C. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, J. Luo, X. F. Luo, V. B. Luong, L. Ma, R. Ma, Y. G. Ma, N. Magdy, R. Manikandhan, S. Margetis, H. S. Matis, G. McNamara, O. Mezhanska, K. Mi, N. G. Minaev, B. Mohanty, M. M. Mondal, I. Mooney, D. A. Morozov, A. Mudrokh, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, E. Nedorezov, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, K. Okubo, B. S. Page, R. Pak, S. Pal, A. Pandav, A. K. Pandey, Y. Panebratsev, T. Pani, P. Parfenov, A. Paul, C. Perkins, B. R. Pokhrel, M. Posik, A. Povarov, T. Protzman, N. K. Pruthi, J. Putschke, Z. Qin, H. Qiu, C. Racz, S. K. Radhakrishnan, A. Rana, R. L. Ray, H. G. Ritter, C. W. Robertson, O. V. Rogachevsky, M. A. Rosales Aguilar, D. Roy, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, E. Samigullin, S. Sato, B. C. Schaefer, W. B. Schmidke, N. Schmitz, J. Seger, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Shen, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, M. Strikhanov, B. Stringfellow, Y. Su, C. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, Z. W. Sweger, A. C. Tamis, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, D. Tlusty, T. Todoroki, M. V. Tokarev, S. Trentalange, P. Tribedy, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, A. N. Vasiliev, V. Verkest, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, J. Wang, K. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, H. Wieman, G. Wilks, S. W. Wissink, J. Wu, X. Wu, Wu X., B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Physics, QC1-999
Abstract

The chiral magnetic effect (CME) is a phenomenon that arises from the QCD anomaly in the presence of an external magnetic field. The experimental search for its evidence has been one of the key goals of the physics program of the Relativistic Heavy-Ion Collider. The STAR Collaboration has previously presented the results of a blind analysis of isobar collisions (_{44}^{96}Ru+_{44}^{96}Ru, _{40}^{96}Zr+_{40}^{96}Zr) in the search for the CME. The isobar ratio (Y) of CME-sensitive observable, charge separation scaled by elliptic anisotropy, is close to but systematically larger than the inverse multiplicity ratio, the naive background baseline. This indicates the potential existence of a CME signal and the presence of remaining nonflow background due to two- and three-particle correlations, which are different between the isobars. In this postblind analysis, we estimate the contributions from those nonflow correlations as a background baseline to Y, utilizing the isobar data as well as Heavy Ion Jet Interaction Generator simulations. This baseline is found consistent with the isobar ratio measurement, and an upper limit of 10% at 95% confidence level is extracted for the CME fraction in the charge separation measurement in isobar collisions at sqrt[s_{NN}]=200 GeV.

Published
2024
Full Text
View/download PDF

2. Measurement of electrons from open heavy-flavor hadron decays in Au+Au collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 200 GeV with the STAR detector

Author

The STAR collaboration, M. I. Abdulhamid, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, S. Aslam, J. Atchison, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, G. Dale-Gau, A. Das, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, N. Herrmann, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, A. Jentsch, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, R. Lacey, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, M. A. Lisa, C. Liu, F. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, W. J. Llope, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, K. Mi, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, C. W. Robertson, M. Robotkova, M. A. Rosales Aguilar, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, M. Stefaniak, D. J. Stewart, B. Stringfellow, Y. Su, A. A. P. Suaide, M. Sumbera, C. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. Tamis, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, G. Wilks, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Heavy Ion Experiments, Heavy Quark Production, Heavy-Ion Collision, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract We report a new measurement of the production of electrons from open heavy-flavor hadron decays (HFEs) at mid-rapidity (|y| < 0.7) in Au+Au collisions at s NN $$ \sqrt{s_{\textrm{NN}}} $$ = 200 GeV. Invariant yields of HFEs are measured for the transverse momentum range of 3.5 < p T < 9 GeV/c in various configurations of the collision geometry. The HFE yields in head-on Au+Au collisions are suppressed by approximately a factor of 2 compared to that in p + p collisions scaled by the average number of binary collisions, indicating strong interactions between heavy quarks and the hot and dense medium created in heavy-ion collisions. Comparison of these results with models provides additional tests of theoretical calculations of heavy quark energy loss in the quark-gluon plasma.

Published
2023
Full Text
View/download PDF

3. Observation of the Electromagnetic Field Effect via Charge-Dependent Directed Flow in Heavy-Ion Collisions at the Relativistic Heavy Ion Collider

Author

M. I. Abdulhamid, B. E. Aboona, J. Adam, J. R. Adams, G. Agakishiev, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, A. Aitbaev, I. Alekseev, E. Alpatov, A. Aparin, S. Aslam, J. Atchison, G. S. Averichev, V. Bairathi, J. G. Ball Cap, K. Barish, P. Bhagat, A. Bhasin, S. Bhatta, S. R. Bhosale, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, J. Ceska, I. Chakaberia, B. K. Chan, Z. Chang, A. Chatterjee, D. Chen, J. Chen, J. H. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, G. Dale-Gau, A. Das, A. P. Dash, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, A. Dhamija, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, O. Eyser, R. Fatemi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, F. A. Flor, C. Fu, T. Gao, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, A. Hamed, Y. Han, M. D. Harasty, J. W. Harris, H. Harrison-Smith, W. He, X. H. He, Y. He, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, A. Jalotra, C. Jena, Y. Ji, J. Jia, C. Jin, X. Ju, E. G. Judd, S. Kabana, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, D. Keane, A. Kechechyan, A. Kiselev, A. G. Knospe, H. S. Ko, L. Kochenda, A. A. Korobitsin, A. Yu. Kraeva, P. Kravtsov, L. Kumar, M. C. Labonte, R. Lacey, J. M. Landgraf, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, H-S. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, T. Lin, Y. Lin, C. Liu, F. Liu, G. Liu, H. Liu, L. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, O. Lomicky, R. S. Longacre, E. M. Loyd, T. Lu, N. S. Lukow, X. F. Luo, V. B. Luong, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, H. S. Matis, G. McNamara, K. Mi, N. G. Minaev, B. Mohanty, M. M. Mondal, I. Mooney, D. A. Morozov, A. Mudrokh, M. I. Nagy, A. S. Nain, J. D. Nam, M. Nasim, E. Nedorezov, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, K. Okubo, B. S. Page, R. Pak, A. Pandav, Y. Panebratsev, T. Pani, P. Parfenov, A. Paul, C. Perkins, B. R. Pokhrel, M. Posik, A. Povarov, T. Protzman, N. K. Pruthi, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, A. Rana, R. L. Ray, H. G. Ritter, C. W. Robertson, O. V. Rogachevsky, M. A. Rosales Aguilar, D. Roy, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, E. Samigullin, S. Sato, B. C. Schaefer, W. B. Schmidke, N. Schmitz, J. Seger, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, T. Shao, M. Sharma, N. Sharma, R. Sharma, S. R. Sharma, A. I. Sheikh, D. Shen, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, F. Si, J. Singh, S. Singha, P. Sinha, M. J. Skoby, Y. Söhngen, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, M. Strikhanov, B. Stringfellow, Y. Su, C. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, Z. W. Sweger, A. C. Tamis, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, D. Tlusty, T. Todoroki, M. V. Tokarev, S. Trentalange, P. Tribedy, S. K. Tripathy, O. D. Tsai, C. Y. Tsang, Z. Tu, J. Tyler, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, A. N. Vasiliev, V. Verkest, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, J. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, H. Wieman, G. Wilks, S. W. Wissink, J. Wu, X. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, W. Zhang, X. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, S. Zhou, Y. Zhou, X. Zhu, M. Zurek, and M. Zyzak

Subjects
Physics, QC1-999
Abstract

The deconfined quark-gluon plasma (QGP) created in relativistic heavy-ion collisions enables the exploration of the fundamental properties of matter under extreme conditions. Noncentral collisions can produce strong magnetic fields on the order of 10^{18} G, which offers a probe into the electrical conductivity of the QGP. In particular, quarks and antiquarks carry opposite charges and receive contrary electromagnetic forces that alter their momenta. This phenomenon can be manifested in the collective motion of final-state particles, specifically in the rapidity-odd directed flow, denoted as v_{1}(y). Here, we present the charge-dependent measurements of dv_{1}/dy near midrapidities for π^{±}, K^{±}, and p(p[over ¯]) in Au+Au and isobar (_{44}^{96}Ru+_{44}^{96}Ru and _{40}^{96}Zr+_{40}^{96}Zr) collisions at sqrt[s_{NN}]=200 GeV, and in Au+Au collisions at 27 GeV, recorded by the STAR detector at the Relativistic Heavy Ion Collider. The combined dependence of the v_{1} signal on collision system, particle species, and collision centrality can be qualitatively and semiquantitatively understood as several effects on constituent quarks. While the results in central events can be explained by the u and d quarks transported from initial-state nuclei, those in peripheral events reveal the impacts of the electromagnetic field on the QGP. Our data put valuable constraints on the electrical conductivity of the QGP in theoretical calculations.

Published
2024
Full Text
View/download PDF

4. Erratum to: Evidence of Mass Ordering of Charm and Bottom Quark Energy Loss in Au+Au Collisions at RHIC

Author

M. S. Abdallah, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, J. Atchison, X. Bai, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, S. Chattopadhyay, D. Chen, J. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, F. M. Fawzi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, A. Francisco, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison, S. He, W. He, X. H. He, Y. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, C. Jena, A. Jentsch, Y. Ji, J. Jia, K. Jiang, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, T. Liu, X. Liu, Y. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, E. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, J. Porter, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, M. Robotkova, J. L. Romero, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F.-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, M. Shao, T. Shao, R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, W. Solyst, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, B. Stringfellow, A. A. P. Suaide, M. Sumbera, C. Sun, X. M. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, Y. Zhou, X. Zhu, M. Zurek, M. Zyzak, and STAR Collaboration

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Published
2023
Full Text
View/download PDF

5. Evidence of Mass Ordering of Charm and Bottom Quark Energy Loss in Au+Au Collisions at RHIC

Author

M. S. Abdallah, B. E. Aboona, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, I. Aggarwal, M. M. Aggarwal, Z. Ahammed, D. M. Anderson, E. C. Aschenauer, J. Atchison, X. Bai, V. Bairathi, W. Baker, J. G. Ball Cap, K. Barish, R. Bellwied, P. Bhagat, A. Bhasin, S. Bhatta, J. Bielcik, J. Bielcikova, J. D. Brandenburg, X. Z. Cai, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, Z. Chang, A. Chatterjee, S. Chattopadhyay, D. Chen, J. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, Y. Cheng, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, I. M. Deppner, A. Dhamija, L. Di Carlo, L. Didenko, P. Dixit, X. Dong, J. L. Drachenberg, E. Duckworth, J. C. Dunlop, J. Engelage, G. Eppley, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, F. M. Fawzi, S. Fazio, C. J. Feng, Y. Feng, E. Finch, Y. Fisyak, A. Francisco, C. Fu, C. A. Gagliardi, T. Galatyuk, F. Geurts, N. Ghimire, A. Gibson, K. Gopal, X. Gou, D. Grosnick, A. Gupta, W. Guryn, A. Hamed, Y. Han, S. Harabasz, M. D. Harasty, J. W. Harris, H. Harrison, S. He, W. He, X. H. He, Y. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, C. Hu, Q. Hu, Y. Hu, H. Huang, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, Y. Huang, T. J. Humanic, D. Isenhower, M. Isshiki, W. W. Jacobs, C. Jena, A. Jentsch, Y. Ji, J. Jia, K. Jiang, C. Jin, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, B. Kimelman, D. Kincses, I. Kisel, A. Kiselev, A. G. Knospe, H. S. Ko, L. K. Kosarzewski, L. Kramarik, L. Kumar, S. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, J. H. Lee, Y. H. Leung, N. Lewis, C. Li, W. Li, X. Li, Y. Li, Z. Li, X. Liang, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, T. Liu, X. Liu, Y. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, E. Loyd, T. Lu, N. S. Lukow, X. F. Luo, L. Ma, R. Ma, Y. G. Ma, N. Magdy, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, G. McNamara, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, A. Mukherjee, M. I. Nagy, A. S. Nain, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, T. Niida, R. Nishitani, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, K. Okubo, B. S. Page, R. Pak, J. Pan, A. Pandav, A. K. Pandey, T. Pani, A. Paul, B. Pawlik, D. Pawlowska, C. Perkins, J. Pluta, B. R. Pokhrel, J. Porter, M. Posik, T. Protzman, V. Prozorova, N. K. Pruthi, M. Przybycien, J. Putschke, Z. Qin, H. Qiu, A. Quintero, C. Racz, S. K. Radhakrishnan, N. Raha, R. L. Ray, R. Reed, H. G. Ritter, M. Robotkova, J. L. Romero, D. Roy, P. Roy Chowdhury, L. Ruan, A. K. Sahoo, N. R. Sahoo, H. Sako, S. Salur, S. Sato, W. B. Schmidke, N. Schmitz, F-J. Seck, J. Seger, R. Seto, P. Seyboth, N. Shah, P. V. Shanmuganathan, M. Shao, T. Shao, R. Sharma, A. I. Sheikh, D. Y. Shen, K. Shen, S. S. Shi, Y. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, J. Singh, S. Singha, P. Sinha, M. J. Skoby, N. Smirnov, Y. Söhngen, W. Solyst, Y. Song, B. Srivastava, T. D. S. Stanislaus, D. J. Stewart, B. Stringfellow, A. A. P. Suaide, M. Sumbera, C. Sun, X. M. Sun, X. Sun, Y. Sun, B. Surrow, Z. W. Sweger, P. Szymanski, A. H. Tang, Z. Tang, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, T. Todoroki, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, T. Truhlar, B. A. Trzeciak, O. D. Tsai, C. Y. Tsang, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, I. Vassiliev, V. Verkest, F. Videbæk, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, X. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, G. D. Westfall, D. Wielanek, H. Wieman, S. W. Wissink, R. Witt, J. Wu, X. Wu, Y. Wu, B. Xi, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. Xu, Z. Xu, G. Yan, Z. Yan, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Ye, L. Yi, K. Yip, Y. Yu, H. Zbroszczyk, W. Zha, C. Zhang, D. Zhang, J. Zhang, S. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, F. Zhao, J. Zhao, M. Zhao, C. Zhou, J. Zhou, Y. Zhou, X. Zhu, M. Zurek, M. Zyzak, and STAR Collaboration

Subjects
Astrophysics, QB460-466, Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract Partons traversing the strongly interacting medium produced in heavy-ion collisions are expected to lose energy depending on their color charge and mass. We measure the nuclear modification factors for charm- and bottom-decay electrons, defined as the ratio of yields, divided by the number of binary nucleon–nucleon collisions, in $$\sqrt{s_{\textrm{NN}}}=200$$ s NN = 200 GeV Au+Au collisions to p+p collisions ( $$R_{\textrm{AA}}$$ R AA ), or in central to peripheral Au+Au collisions ( $$R_{\textrm{CP}}$$ R CP ). We find the bottom-decay electron $$R_{\textrm{AA}}$$ R AA and $$R_{\textrm{CP}}$$ R CP to be significantly higher than those of charm-decay electrons. Model calculations including mass-dependent parton energy loss in a strongly coupled medium are consistent with the measured data. These observations provide evidence of mass ordering of charm and bottom quark energy loss when traversing through the strongly coupled medium created in heavy-ion collisions.

Published
2022
Full Text
View/download PDF

6. Measurement of the central exclusive production of charged particle pairs in proton-proton collisions at s $$ \sqrt{s} $$ = 200 GeV with the STAR detector at RHIC

Author

The STAR collaboration, J. Adam, L. Adamczyk, J. R. Adams, J. K. Adkins, G. Agakishiev, M. M. Aggarwal, Z. Ahammed, I. Alekseev, D. M. Anderson, A. Aparin, E. C. Aschenauer, M. U. Ashraf, F. G. Atetalla, A. Attri, G. S. Averichev, V. Bairathi, K. Barish, A. Behera, R. Bellwied, A. Bhasin, J. Bielcik, J. Bielcikova, L. C. Bland, I. G. Bordyuzhin, J. D. Brandenburg, A. V. Brandin, J. Butterworth, H. Caines, M. Calderón de la Barca Sánchez, D. Cebra, I. Chakaberia, P. Chaloupka, B. K. Chan, F-H. Chang, Z. Chang, N. Chankova-Bunzarova, A. Chatterjee, D. Chen, J. H. Chen, X. Chen, Z. Chen, J. Cheng, M. Cherney, M. Chevalier, S. Choudhury, W. Christie, X. Chu, H. J. Crawford, M. Csanád, M. Daugherity, T. G. Dedovich, I. M. Deppner, A. A. Derevschikov, L. Didenko, X. Dong, J. L. Drachenberg, J. C. Dunlop, T. Edmonds, N. Elsey, J. Engelage, G. Eppley, R. Esha, S. Esumi, O. Evdokimov, A. Ewigleben, O. Eyser, R. Fatemi, S. Fazio, P. Federic, J. Fedorisin, C. J. Feng, Y. Feng, P. Filip, E. Finch, Y. Fisyak, A. Francisco, L. Fulek, C. A. Gagliardi, T. Galatyuk, F. Geurts, A. Gibson, K. Gopal, D. Grosnick, W. Guryn, A. I. Hamad, A. Hamed, S. Harabasz, J. W. Harris, S. He, W. He, X. H. He, S. Heppelmann, N. Herrmann, E. Hoffman, L. Holub, Y. Hong, S. Horvat, Y. Hu, H. Z. Huang, S. L. Huang, T. Huang, X. Huang, T. J. Humanic, P. Huo, G. Igo, D. Isenhower, W. W. Jacobs, C. Jena, A. Jentsch, Y. JI, J. Jia, K. Jiang, S. Jowzaee, X. Ju, E. G. Judd, S. Kabana, M. L. Kabir, S. Kagamaster, D. Kalinkin, K. Kang, D. Kapukchyan, K. Kauder, H. W. Ke, D. Keane, A. Kechechyan, M. Kelsey, Y. V. Khyzhniak, D. P. Kikoła, C. Kim, B. Kimelman, D. Kincses, T. A. Kinghorn, I. Kisel, A. Kiselev, A. Kisiel, M. Kocan, L. Kochenda, L. K. Kosarzewski, L. Kramarik, P. Kravtsov, K. Krueger, N. Kulathunga Mudiyanselage, L. Kumar, R. Kunnawalkam Elayavalli, J. H. Kwasizur, R. Lacey, S. Lan, J. M. Landgraf, J. Lauret, A. Lebedev, R. Lednicky, J. H. Lee, Y. H. Leung, C. Li, W. Li, X. Li, Y. Li, Y. Liang, R. Licenik, T. Lin, Y. Lin, M. A. Lisa, F. Liu, H. Liu, P. Liu, T. Liu, X. Liu, Y. Liu, Z. Liu, T. Ljubicic, W. J. Llope, R. S. Longacre, N. S. Lukow, S. Luo, X. Luo, G. L. Ma, L. Ma, R. Ma, Y. G. Ma, N. Magdy, R. Majka, D. Mallick, S. Margetis, C. Markert, H. S. Matis, J. A. Mazer, N. G. Minaev, S. Mioduszewski, B. Mohanty, M. M. Mondal, I. Mooney, Z. Moravcova, D. A. Morozov, M. Nagy, J. D. Nam, Md. Nasim, K. Nayak, D. Neff, J. M. Nelson, D. B. Nemes, M. Nie, G. Nigmatkulov, T. Niida, L. V. Nogach, T. Nonaka, A. S. Nunes, G. Odyniec, A. Ogawa, S. Oh, V. A. Okorokov, B. S. Page, R. Pak, A. Pandav, Y. Panebratsev, B. Pawlik, D. Pawlowska, H. Pei, C. Perkins, L. Pinsky, R. L. Pintér, J. Pluta, J. Porter, M. Posik, N. K. Pruthi, M. Przybycien, J. Putschke, H. Qiu, A. Quintero, S. K. Radhakrishnan, S. Ramachandran, R. L. Ray, R. Reed, H. G. Ritter, J. B. Roberts, O. V. Rogachevskiy, J. L. Romero, L. Ruan, J. Rusnak, N. R. Sahoo, H. Sako, S. Salur, J. Sandweiss, S. Sato, W. B. Schmidke, N. Schmitz, B. R. Schweid, F. Seck, J. Seger, M. Sergeeva, R. Seto, P. Seyboth, N. Shah, E. Shahaliev, P. V. Shanmuganathan, M. Shao, F. Shen, W. Q. Shen, S. S. Shi, Q. Y. Shou, E. P. Sichtermann, R. Sikora, M. Simko, J. Singh, S. Singha, N. Smirnov, W. Solyst, P. Sorensen, H. M. Spinka, B. Srivastava, T. D. S. Stanislaus, M. Stefaniak, D. J. Stewart, M. Strikhanov, B. Stringfellow, A. A. P. Suaide, M. Sumbera, B. Summa, X. M. Sun, X. Sun, Y. Sun, B. Surrow, D. N. Svirida, P. Szymanski, A. H. Tang, Z. Tang, A. Taranenko, T. Tarnowsky, J. H. Thomas, A. R. Timmins, D. Tlusty, M. Tokarev, C. A. Tomkiel, S. Trentalange, R. E. Tribble, P. Tribedy, S. K. Tripathy, O. D. Tsai, Z. Tu, T. Ullrich, D. G. Underwood, I. Upsal, G. Van Buren, J. Vanek, A. N. Vasiliev, I. Vassiliev, F. Videbæk, S. Vokal, S. A. Voloshin, F. Wang, G. Wang, J. S. Wang, P. Wang, Y. Wang, Z. Wang, J. C. Webb, P. C. Weidenkaff, L. Wen, G. D. Westfall, H. Wieman, S. W. Wissink, R. Witt, Y. Wu, Z. G. Xiao, G. Xie, W. Xie, H. Xu, N. Xu, Q. H. Xu, Y. F. Xu, Y. Xu, Z. Xu, C. Yang, Q. Yang, S. Yang, Y. Yang, Z. Yang, Z. Ye, L. Yi, K. Yip, H. Zbroszczyk, W. Zha, D. Zhang, S. Zhang, X. P. Zhang, Y. Zhang, Z. J. Zhang, Z. Zhang, J. Zhao, C. Zhong, C. Zhou, X. Zhu, Z. Zhu, M. Zurek, and M. Zyzak

Subjects
Diffraction, Forward physics, Hadron-Hadron scattering (experiments), Nuclear and particle physics. Atomic energy. Radioactivity, QC770-798
Abstract

Abstract We report on the measurement of the Central Exclusive Production of charged particle pairs h + h − (h = π, K, p) with the STAR detector at RHIC in proton-proton collisions at s $$ \sqrt{s} $$ = 200 GeV. The charged particle pairs produced in the reaction pp → p′ + h + h − + p′ are reconstructed from the tracks in the central detector and identified using the specific energy loss and the time of flight method, while the forward-scattered protons are measured in the Roman Pot system. Exclusivity of the event is guaranteed by requiring the transverse momentum balance of all four final-state particles. Differential cross sections are measured as functions of observables related to the central hadronic final state and to the forward-scattered protons. They are measured in a fiducial region corresponding to the acceptance of the STAR detector and determined by the central particles’ transverse momenta and pseudorapidities as well as by the forward-scattered protons’ momenta. This fiducial region roughly corresponds to the square of the four-momentum transfers at the proton vertices in the range 0.04 GeV2 < −t 1 , −t 2 < 0.2 GeV2, invariant masses of the charged particle pairs up to a few GeV and pseudorapidities of the centrally-produced hadrons in the range |η| < 0.7. The measured cross sections are compared to phenomenological predictions based on the Double Pomeron Exchange (DPE) model. Structures observed in the mass spectra of π + π − and K + K − pairs are consistent with the DPE model, while angular distributions of pions suggest a dominant spin-0 contribution to π + π − production. For π + π − production, the fiducial cross section is extrapolated to the Lorentz-invariant region, which allows decomposition of the invariant mass spectrum into continuum and resonant contributions. The extrapolated cross section is well described by the continuum production and at least three resonances, the f 0(980), f 2(1270) and f 0(1500), with a possible small contribution from the f 0(1370). Fits to the extrapolated differential cross section as a function of t 1 and t 2 enable extraction of the exponential slope parameters in several bins of the invariant mass of π + π − pairs. These parameters are sensitive to the size of the interaction region.

Published
2020
Full Text
View/download PDF

7. Cross-hemispheric transport of central African biomass burning pollutants: implications for downwind ozone production

Author

E. Real, E. Orlandi, K. S. Law, F. Fierli, D. Josset, F. Cairo, H. Schlager, S. Borrmann, D. Kunkel, C. M. Volk, J. B. McQuaid, D. J. Stewart, J. Lee, A. C. Lewis, J. R. Hopkins, F. Ravegnani, A. Ulanovski, and C. Liousse

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Pollutant plumes with enhanced concentrations of trace gases and aerosols were observed over the southern coast of West Africa during August 2006 as part of the AMMA wet season field campaign. Plumes were observed both in the mid and upper troposphere. In this study we examined the origin of these pollutant plumes, and their potential to photochemically produce ozone (O3) downwind over the Atlantic Ocean. Their possible contribution to the Atlantic O3 maximum is also discussed. Runs using the BOLAM mesoscale model including biomass burning carbon monoxide (CO) tracers were used to confirm an origin from central African biomass burning fires. The plumes measured in the mid troposphere (MT) had significantly higher pollutant concentrations over West Africa compared to the upper tropospheric (UT) plume. The mesoscale model reproduces these differences and the two different pathways for the plumes at different altitudes: transport to the north-east of the fire region, moist convective uplift and transport to West Africa for the upper tropospheric plume versus north-west transport over the Gulf of Guinea for the mid-tropospheric plume. Lower concentrations in the upper troposphere are mainly due to enhanced mixing during upward transport. Model simulations suggest that MT and UT plumes are 16 and 14 days old respectively when measured over West Africa. The ratio of tracer concentrations at 600 hPa and 250 hPa was estimated for 14–15 August in the region of the observed plumes and compares well with the same ratio derived from observed carbon dioxide (CO2) enhancements in both plumes. It is estimated that, for the period 1–15 August, the ratio of Biomass Burning (BB) tracer concentration transported in the UT to the ones transported in the MT is 0.6 over West Africa and the equatorial South Atlantic. Runs using a photochemical trajectory model, CiTTyCAT, initialized with the observations, were used to estimate in-situ net photochemical O3 production rates in these plumes during transport downwind of West Africa. The mid-troposphere plume spreads over altitude between 1.5 and 6 km over the Atlantic Ocean. Even though the plume was old, it was still very photochemically active (mean net O3 production rates over 10 days of 2.6 ppbv/day and up to 7 ppbv/day during the first days) above 3 km especially during the first few days of transport westward. It is also shown that the impact of high aerosol loads in the MT plume on photolysis rates serves to delay the peak in modelled O3 concentrations. These results suggest that a significant fraction of enhanced O3 in mid-troposphere over the Atlantic comes from BB sources during the summer monsoon period. According to simulated occurrence of such transport, BB may be the main source for O3 enhancement in the equatorial south Atlantic MT, at least in August 2006. The upper tropospheric plume was also still photochemically active, although mean net O3 production rates were slower (1.3 ppbv/day). The results suggest that, whilst the transport of BB pollutants to the UT is variable (as shown by the mesoscale model simulations), pollution from biomass burning can make an important contribution to additional photochemical production of O3 in addition to other important sources such as nitrogen oxides (NOx) from lightning.

Published
2010

8. Direct estimates of emissions from the megacity of Lagos

Author

R. M. Purvis, C. E. Reeves, D. J. Stewart, D. J. Parker, J. H Marsham, J. B. McQuaid, A. C. Lewis, J. D. Lee, M. J. Evans, and J. R. Hopkins

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

We report here top-down emissions estimates for an African megacity. A boundary layer circumnavigation of Lagos, Nigeria was completed using the FAAM BAe146 aircraft as part of the AMMA project. These observations together with an inferred boundary layer height allow the flux of pollutants to be calculated. Extrapolation gives annual emissions for CO, NOx, and VOCs of 1.44 Tg yr−1, 0.03 Tg yr−1 and 0.37 Tg yr−1 respectively with uncertainties of +250/−60%. These inferred emissions are consistent with bottom-up estimates for other developing megacities and are attributed to the evaporation of fuels, mobile combustion and natural gas emissions.

Published
2009

9. Factors controlling the distribution of ozone in the West African lower troposphere during the AMMA (African Monsoon Multidisciplinary Analysis) wet season campaign

Author

M. Saunois, C. E. Reeves, C. H. Mari, J. G. Murphy, D. J. Stewart, G. P. Mills, D. E. Oram, and R. M. Purvis

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Ozone and its precursors were measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the monsoon season 2006 as part of the African Monsoon Multidisciplinary Analysis (AMMA) campaign. One of the main features observed in the west African boundary layer is the increase of the ozone mixing ratios from 25 ppbv over the forested area (south of 12° N) up to 40 ppbv over the Sahelian area. We employ a two-dimensional (latitudinal versus vertical) meteorological model coupled with an O3-NOx-VOC chemistry scheme to simulate the distribution of trace gases over West Africa during the monsoon season and to analyse the processes involved in the establishment of such a gradient. Including an additional source of NO over the Sahelian region to account for NO emitted by soils we simulate a mean NOx concentration of 0.7 ppbv at 16° N versus 0.3 ppbv over the vegetated region further south in reasonable agreement with the observations. As a consequence, ozone is photochemically produced with a rate of 0.25 ppbv h−1 over the vegetated region whilst it reaches up to 0.75 ppbv h−1 at 16° N. We find that the modelled gradient is due to a combination of enhanced deposition to vegetation, which decreases the ozone levels by up to 11 pbbv, and the aforementioned enhanced photochemical production north of 12° N. The peroxy radicals required for this enhanced production in the north come from the oxidation of background CO and CH4 as well as from VOCs. Sensitivity studies reveal that both the background CH4 and partially oxidised VOCs, produced from the oxidation of isoprene emitted from the vegetation in the south, contribute around 5–6 ppbv to the ozone gradient. These results suggest that the northward transport of trace gases by the monsoon flux, especially during nighttime, can have a significant, though secondary, role in determining the ozone gradient in the boundary layer. Convection, anthropogenic emissions and NO produced from lightning do not contribute to the establishment of the discussed ozone gradient.

Published
2009

10. Biogenic nitrogen oxide emissions from soils ─ impact on NOx and ozone over West Africa during AMMA (African Monsoon Multidisciplinary Experiment): modelling study

Author

J.-P. Chaboureau, C. Mari, R. Dupont, D. Serça, D. J. Stewart, C. E. Reeves, C. Delon, and P. Tulet

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Nitrogen oxide biogenic emissions from soils are driven by soil and environmental parameters. The relationship between these parameters and NO fluxes is highly non linear. A new algorithm, based on a neural network calculation, is used to reproduce the NO biogenic emissions linked to precipitations in the Sahel on the 6 August 2006 during the AMMA campaign. This algorithm has been coupled in the surface scheme of a coupled chemistry dynamics model (MesoNH Chemistry) to estimate the impact of the NO emissions on NOx and O3 formation in the lower troposphere for this particular episode. Four different simulations on the same domain and at the same period are compared: one with anthropogenic emissions only, one with soil NO emissions from a static inventory, at low time and space resolution, one with NO emissions from neural network, and one with NO from neural network plus lightning NOx. The influence of NOx from lightning is limited to the upper troposphere. The NO emission from soils calculated with neural network responds to changes in soil moisture giving enhanced emissions over the wetted soil, as observed by aircraft measurements after the passing of a convective system. The subsequent enhancement of NOx and ozone is limited to the lowest layers of the atmosphere in modelling, whereas measurements show higher concentrations above 1000 m. The neural network algorithm, applied in the Sahel region for one particular day of the wet season, allows an immediate response of fluxes to environmental parameters, unlike static emission inventories. Stewart et al (2008) is a companion paper to this one which looks at NOx and ozone concentrations in the boundary layer as measured on a research aircraft, examines how they vary with respect to the soil moisture, as indicated by surface temperature anomalies, and deduces NOx fluxes. In this current paper the model-derived results are compared to the observations and calculated fluxes presented by Stewart et al (2008).

Published
2008

11. Biogenic nitrogen oxide emissions from soils: impact on NOx and ozone over west Africa during AMMA (African Monsoon Multidisciplinary Analysis): observational study

Author

J. B. McQuaid, C. E. Reeves, C. M. Taylor, and D. J. Stewart

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

Chemical and meteorological parameters measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the African Monsoon Multidisciplinary Analysis (AMMA) campaign are presented to show the impact of NOx emissions from recently wetted soils in West Africa. NO emissions from soils have been previously observed in many geographical areas with different types of soil/vegetation cover during small scale studies and have been inferred at large scales from satellite measurements of NOx. This study is the first dedicated to showing the emissions of NOx at an intermediate scale between local surface sites and continental satellite measurements. The measurements reveal pronounced mesoscale variations in NOx concentrations closely linked to spatial patterns of antecedent rainfall. Fluxes required to maintain the NOx concentrations observed by the BAe-146 in a number of cases studies and for a range of assumed OH concentrations (1×106 to 1×107 molecules cm−3) are calculated to be in the range 8.4 to 36.1 ng N m−2 s−1. These values are comparable to the range of fluxes from 0.5 to 28 ng N m−2 s−1 reported from small scale field studies in a variety of non-nutrient rich tropical and sub-tropical locations reported in the review of Davidson and Kingerlee (1997). The fluxes calculated in the present study have been scaled up to cover the area of the Sahel bounded by 10 to 20 N and 10 E to 20 W giving an estimated emission of 0.03 to 0.30 Tg N from this area for July and August 2006. The observed chemical data also suggest that the NOx emitted from soils is taking part in ozone formation as ozone concentrations exhibit similar fine scale structure to the NOx, with enhancements over the wet soils. Such variability can not be explained on the basis of transport from other areas. Delon et al. (2008) is a companion paper to this one which models the impact of soil NOx emissions on the NOx and ozone concentration over West Africa during AMMA. It employs an artificial neural network to define the emissions of NOx from soils, integrated into a coupled chemistry-dynamics model. The results are compared to the observed data presented in this paper. Here we compare fluxes deduced from the observed data with the model-derived values from Delon et al. (2008).

Published
2008

12. Reactive uptake coefficients for heterogeneous reaction of N2O5 with submicron aerosols of NaCl and natural sea salt

Author

D. J. Stewart, P. T. Griffiths, and R. A. Cox

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

The kinetics of uptake of gaseous N2O5 on submicron aerosols containing NaCl and natural sea salt have been investigated in a flow reactor as a function of relative humidity (RH) in the range 30-80% at 295±2K and a total pressure of 1bar. The measured uptake coefficients, γ, were larger on the aerosols containing sea salt compared to those of pure NaCl, and in both cases increased with increasing RH. These observations are explained in terms of the variation in the size of the salt droplets, which leads to a limitation in the uptake rate into small particles. After correction for this effect the uptake coefficients are independent of relative humidity, and agree with those measured previously on larger droplets. A value of γ=0.025 is recommended for the reactive uptake coefficient for N2O5 on deliquesced sea salt droplets at 298K and RH>40%.

Published
2004

13. Intercomparison of aircraft instruments on board the C-130 and Falcon 20 over southern Germany during EXPORT 2000

Author

N. Brough, C. E. Reeves, S. A. Penkett, D. J. Stewart, K. Dewey, J. Kent, H. Barjat, P. S. Monks, H. Ziereis, P. Stock, H. Huntrieser, and H. Schlager

Subjects
Physics, QC1-999, Chemistry, QD1-999
Abstract

In the summer 2000 EXPORT aircraft campaign (European eXport of Precursors and Ozone by long-Range Transport), two comprehensively instrumented research aircraft measuring a variety of chemical species flew wing tip to wing tip for a period of one and a quarter hours. During this interval a comparison was undertaken of the measurements of nitrogen oxide (NO), odd nitrogen species (NOy), carbon monoxide (CO) and ozone (O3). The comparison was performed at two different flight levels, which provided a 10-fold variation in the concentrations of both NO (10 to 1000 parts per trillion by volume (pptv)) and NOy (200 to over 2500 pptv). Large peaks of NO and NOy observed from the Falcon 20, which were at first thought to be from the exhaust of the C-130, were also detected on the 4 channel NOxy instrument aboard the C-130. These peaks were a good indication that both aircraft were in the same air mass and that the Falcon 20 was not in the exhaust plume of the C-130. Correlations and statistical analysis are presented between the instruments used on the two separate aircraft platforms. These were found to be in good agreement giving a high degree of correlation for the ambient air studied. Any deviations from the correlations are accounted for in the estimated inaccuracies of the instruments. These results help to establish that the instruments aboard the separate aircraft are reliably able to measure the corresponding chemical species in the range of conditions sampled and that data collected by both aircraft can be co-ordinated for purposes of interpretation.

Published
2003

14. Cost-effectiveness of emergency versus delayed laparoscopic cholecystectomy for acute gallbladder pathology

Author

A J Sutton, R S Vohra, M Hollyman, P J Marriott, A Buja, D Alderson, S Pasquali, E A Griffiths, P Spreadborough, A Kirkham, S Fenwick, M Elmasry, Q M Nunes, D Kennedy, R B Khan, M A S Khan, C J Magee, S M Jones, D Mason, C P Parappally, P Mathur, M Saunders, S Jamel, S Ul Haque, S Zafar, M H Shiwani, N Samuel, F Dar, A Jackson, B Lovett, S Dindyal, H Winter, T Fletcher, S Rahman, K Wheatley, T Nieto, S Ayaani, H Youssef, R S Nijjar, H Watkin, D Naumann, S Emesih, P B Sarmah, K Lee, N Joji, J Heath, R L Teasdale, C Weerasinghe, P J Needham, H Welbourn, L Forster, D Finch, J M Blazeby, W Robb, A G K McNair, A Hrycaiczuk, A Charalabopoulos, S Kadirkamanathan, C-B Tang, N V G Jayanthi, N Noor, B Dobbins, A J Cockbain, A Nilsen-Nunn, J de Siqueira, M Pellen, J B Cowley, W-M Ho, V Miu, T J White, K A Hodgkins, A Kinghorn, M G Tutton, Y A Al-Abed, D Menzies, A Ahmad, J Reed, S Khan, D Monk, L J Vitone, G Murtaza, A Joel, S Brennan, D Shier, C Zhang, T Yoganathan, S J Robinson, I J D McCallum, M J Jones, M Elsayed, E Tuck, J Wayman, K Carney, S Aroori, K B Hosie, A Kimble, D M Bunting, A S Fawole, M Basheer, R V Dave, J Sarveswaran, E Jones, C Kendal, M P Tilston, M Gough, T Wallace, S Singh, J Downing, K A Mockford, E Issa, N Shah, N Chauhan, T R Wilson, A Forouzanfar, J R L Wild, E Nofal, C Bunnell, K Madbak, S T V Rao, L Devoto, N Siddiqi, Z Khawaja, J C Hewes, L Gould, A Chambers, D U Rodriguez, G Sen, S Robinson, F Bartlett, D M Rae, T E J Stevenson, K Sarvananthan, S J Dwerryhouse, S M Higgs, O J Old, T J Hardy, R Shah, S T Hornby, K Keogh, L Frank, M Al-Akash, E A Upchurch, R J Frame, M Hughes, C Jelley, S Weaver, S Roy, T O Sillo, G Galanopoulos, T Cuming, P Cunha, S Tayeh, S Kaptanis, M Heshaishi, A Eisawi, M Abayomi, W S Ngu, K Fleming, D S Bajwa, V Chitre, K Aryal, P Ferris, M Silva, S Lammy, S Mohamed, A Khawaja, A Hussain, M A Ghazanfar, M I Bellini, H Ebdewi, M Elshaer, G Gravante, B Drake, A Ogedegbe, D Mukherjee, C Arhi, L G N Iqbal, N F Watson, S K Aggarwal, P Orchard, E Villatoro, P D Willson, J Mok, T Woodman, J Deguara, G Garcea, B I Babu, A R Dennison, D Malde, D Lloyd, S Satheesan, O Al-Taan, A Boddy, J P Slavin, R P Jones, L Ballance, S Gerakopoulos, P Jambulingam, S Mansour, N Sakai, V Acharya, M M Sadat, L Karim, D Larkin, K Amin, A Khan, J Law, S Jamdar, S R Smith, K Sampat, K M O'shea, M Manu, F M Asprou, N S Malik, J Chang, M Johnstone, M Lewis, G P Roberts, B Karavadra, E Photi, J Hewes, D Rodriguez, D A O'Reilly, A J Rate, H Sekhar, L T Henderson, B Z Starmer, P O Coe, S Tolofari, J Barrie, G Bashir, J Sloane, S Madanipour, C Halkias, A E J Trevatt, D W Borowski, J Hornsby, M J Courtney, S Virupaksha, K Seymour, H Hawkins, S Bawa, P V Gallagher, A Reid, P Wood, J G Finch, J Parmar, E Stirland, J Gardner-Thorpe, A Al-Muhktar, M Peterson, A Majeed, F M Bajwa, J Martin, A Choy, A Tsang, N Pore, D R Andrew, W Al-Khyatt, C Taylor, S Bhandari, D Subramanium, S K C Toh, N C Carter, S Tate, B Pearce, D Wainwright, S J Mercer, B Knight, V Vijay, S Alagaratnam, S Sinha, S S El-Hasani, A A Hussain, V Bhattacharya, N Kansal, T Fasih, C Jackson, M N Siddiqui, I A Chishti, I J Fordham, Z Siddiqui, H Bausbacher, I Geogloma, K Gurung, G Tsavellas, P Basynat, A K Shrestha, S Basu, A C Mohan, M Harilingam, M Rabie, M Akhtar, P Kumar, S F Jafferbhoy, N Hussain, S Raza, M Haque, I Alam, R Aseem, S Patel, M Asad, M I Booth, W R Ball, C P J Wood, A C Pinho-Gomes, A Kausar, M R Obeidallah, J Varghase, J Lodhia, D Bradley, C Rengifo, D Lindsay, S Gopalswamy, I Finlay, S Wardle, N Bullen, S Y Iftikhar, A Awan, J Ahmed, P Leeder, G Fusai, G Bond-Smith, A Psica, Y Puri, D Hou, F Noble, K Szentpali, J Broadhurst, R Date, M R Hossack, Y L Goh, P Turner, V Shetty, M Riera, C A W Macano, A Sukha, S R Preston, J R Hoban, D J Puntis, S V Williams, R Krysztopik, J Kynaston, J Batt, M Doe, A Goscimski, G H Jones, C Hall, N Carty, S Panteleimonitis, R T Gunasekera, A R G Sheel, H Lennon, C Hindley, M Reddy, R Kenny, N Elkheir, E R McGlone, R Rajaganeshan, K Hancorn, A Hargreaves, R Prasad, D A Longbotham, D Vijayanand, I Wijetunga, P Ziprin, C R Nicolay, G Yeldham, E Read, J A Gossage, R C Rolph, H Ebied, M Phull, M A Khan, M Popplewell, D Kyriakidis, N Henley, J R Packer, L Derbyshire, J Porter, S Appleton, M Farouk, M Basra, N A Jennings, S Ali, V Kanakala, H Ali, R Lane, R Dickson-Lowe, P Zarsadias, D Mirza, S Puig, K Al Amari, D Vijayan, R Sutcliffe, R Marudanayagam, Z Hamady, A R Prasad, A Patel, D Durkin, P Kaur, L Bowen, J P Byrne, K L Pearson, T G Delisle, J Davies, M A Tomlinson, M A Johnpulle, C Slawinski, A Macdonald, J Nicholson, K Newton, J Mbuvi, A Farooq, B S Mothe, Z Zafrani, D Brett, J Francombe, J Barnes, M Cheung, A Z Al-Bahrani, G Preziosi, T Urbonas, J Alberts, M Mallik, K Patel, A Segaran, T Doulias, P A Sufi, C Yao, S Pollock, A Manzelli, S Wajed, M Kourkulos, R Pezzuto, M Wadley, E Hamilton, S Jaunoo, R Padwick, M Sayegh, R C Newton, M Hebbar, S F Farag, J Spearman, M F Hamdan, C D'Costa, C Blane, M Giles, M B Peter, N A Hirst, T Hossain, A Pannu, Y El-Dhuwaib, T E M Morrison, G W Taylor, R L E Thompson, K McCune, P Loughlin, R Lawther, C K Byrnes, D J Simpson, A Mawhinney, C Warren, D McKay, C McIlmunn, S Martin, M MacArtney, T Diamond, P Davey, C Jones, J M Clements, R Digney, W M Chan, S McCain, S Gull, A Janeczko, E Dorrian, A Harris, S Dawson, D Johnston, B McAree, E Ghareeb, G Thomas, M Connelly, S McKenzie, K Cieplucha, G Spence, W Campbell, G Hooks, N Bradley, A D K Hill, J T Cassidy, M Boland, P Burke, D M Nally, E Khogali, W Shabo, E Iskandar, G P McEntee, M A O'Neill, C Peirce, E M Lyons, A W O'Sullivan, R Thakkar, P Carroll, I Ivanovski, P Balfe, M Lee, D C Winter, M E Kelly, E Hoti, D Maguire, P Karunakaran, J G Geoghegan, F McDermott, S T Martin, K S Cross, F Cooke, S Zeeshan, J O Murphy, K Mealy, H M Mohan, Y Nedujchelyn, M F Ullah, I Ahmed, F Giovinazzo, J Milburn, S Prince, E Brooke, J Buchan, A M Khalil, E M Vaughan, M I Ramage, R C Aldridge, S Gibson, G A Nicholson, D G Vass, A J Grant, D J Holroyd, M A Jones, C M L R Sutton, P O'Dwyer, F Nilsson, B Weber, T K Williamson, K Lalla, A Bryant, C R Carter, C R Forrest, D I Hunter, A H Nassar, M N Orizu, K Knight, H Qandeel, S Suttie, R Belding, A McClarey, A T Boyd, G J K Guthrie, P J Lim, A Luhmann, A J M Watson, C H Richards, L Nicol, M Madurska, E Harrison, K M Boyce, A Roebuck, G Ferguson, P Pati, M S J Wilson, F Dalgaty, L Fothergill, P J Driscoll, K L Mozolowski, V Banwell, S P Bennett, P N Rogers, B L Skelly, C L Rutherford, A K Mirza, T Lazim, H C C Lim, D Duke, T Ahmed, W D Beasley, M D Wilkinson, G Maharaj, C Malcolm, T H Brown, G M Shingler, N Mowbray, R Radwan, P Morcous, S Wood, A Kadhim, D J Stewart, A L Baker, N Tanner, H Shenoy, S Hafiz, J A De Marchi, D Singh-Ranger, E Hisham, P Ainley, S O'Neill, J Terrace, S Napetti, B Hopwood, T Rhys, S Kanavati, M Coats, D Aleksandrov, C Kallaway, S Yahya, A Templeton, M Trotter, C Lo, A Dhillon, N Heywood, Y Aawsaj, A Hamdan, O Reece-Bolton, A McGuigan, Y Shahin, A Ali, A Luther, J A Nicholson, I Rajendran, M Boal, and J Ritchie

Subjects
Pathology, medicine.medical_specialty, Cost effectiveness, medicine.medical_treatment, Cost-Benefit Analysis, Gallbladder disease, Population, Cholecystitis, Acute, 030230 surgery, State Medicine, Time-to-Treatment, 03 medical and health sciences, 0302 clinical medicine, medicine, Humans, education, education.field_of_study, Laparoscopyc cholecystectomy, business.industry, emergency, Cost-effectiveness analysis, Gallbladder, General surgery, medicine.disease, United Kingdom, Quality-adjusted life year, delayed surgery, medicine.anatomical_structure, Models, Economic, Cholecystectomy, Laparoscopic, Centre for Surgical Research, Cholecystitis, 030211 gastroenterology & hepatology, Surgery, Cholecystectomy, Quality-Adjusted Life Years, Emergencies, business, Cohort study
Abstract

Background The optimal timing of cholecystectomy for patients admitted with acute gallbladder pathology is unclear. Some studies have shown that emergency cholecystectomy during the index admission can reduce length of hospital stay with similar rates of conversion to open surgery, complications and mortality compared with a ‘delayed’ operation following discharge. Others have reported that cholecystectomy during the index acute admission results in higher morbidity, extended length of stay and increased costs. This study examined the cost-effectiveness of emergency versus delayed cholecystectomy for acute benign gallbladder disease. Methods Using data from a prospective population-based cohort study examining the outcomes of cholecystectomy in the UK and Ireland, a model-based cost–utility analysis was conducted from the perspective of the UK National Health Service, with a 1-year time horizon for costs and outcomes. Probabilistic sensitivity analysis was used to investigate the impact of parameter uncertainty on the results obtained from the model. Results Emergency cholecystectomy was found to be less costly (£4570 versus £4720; €5484 versus €5664) and more effective (0·8868 versus 0·8662 QALYs) than delayed cholecystectomy. Probabilistic sensitivity analysis showed that the emergency strategy is more than 60 per cent likely to be cost-effective across willingness-to-pay values for the QALY from £0 to £100 000 (€0–120 000). Conclusion Emergency cholecystectomy is less costly and more effective than delayed cholecystectomy. This approach is likely to be beneficial to patients in terms of improved health outcomes and to the healthcare provider owing to the reduced costs.

Published
2017

15. Overview: oxidant and particle photochemical processes above a south-east Asian tropical rainforest (the OP3 project): introduction, rationale, location characteristics and tools

Author

Paul I. Palmer, Eiko Nemitz, Ben Langford, Dwayne E. Heard, P. DiCarlo, Hilke Oetjen, M. Irwin, David Fowler, Paul S. Monks, Nicola Carslaw, Trevor Ingham, R. C. Pike, A. Karunaharan, James Dorsey, Roisin Commane, Claire E. Reeves, V. Nicolas-Perea, Graham P. Mills, Glenn Carver, Alastair C. Lewis, Alex Guenther, C. N. Hewitt, Martin Gallagher, Anoop S. Mahajan, S. F. Lim, Pawel K. Misztal, Carole Helfter, K. L. Furneaux, David E. Oram, M. P. Barkley, John M. C. Plane, S. Malpass, Fay Davies, Mathew J. Evans, James R. Hopkins, Gavin Phillips, Brian Davison, James D. Lee, D. J. Stewart, Daniel Stone, Hugh Coe, Gordon McFiggans, A. R. MacKenzie, John A. Pyle, Nick A. Chappell, Peter Edwards, Sarah Moller, Niall Robinson, C. Di Marco, Chris G. Collier, Lisa K. Whalley, Thomas A. M. Pugh, S. M. MacDonald, Xiaobo Yin, and Chris Jones

Subjects
Canopy, Atmospheric Science, Reactive nitrogen, TRACE GASES, Eddy covariance, MONSOON MULTIDISCIPLINARY ANALYSIS, Rainforest, FLUX MEASUREMENTS, VOLATILE ORGANIC-COMPOUNDS, Photochemistry, lcsh:QC1-999, Trace gas, EDDY-COVARIANCE, COMPOUND EMISSIONS, Atmosphere, lcsh:Chemistry, lcsh:QD1-999, TROPOSPHERIC NITROGEN-DIOXIDE, Climatology, Atmospheric chemistry, ISOPRENE EMISSIONS, MASTER CHEMICAL MECHANISM, lcsh:Physics, Tropical rainforest, MCM V3 PART
Abstract

In April–July 2008, intensive measurements were made of atmospheric composition and chemistry in Sabah, Malaysia, as part of the "Oxidant and particle photochemical processes above a South-East Asian tropical rainforest" (OP3) project. Fluxes and concentrations of trace gases and particles were made from and above the rainforest canopy at the Bukit Atur Global Atmosphere Watch station and at the nearby Sabahmas oil palm plantation, using both ground-based and airborne measurements. Here, the measurement and modelling strategies used, the characteristics of the sites and an overview of data obtained are described. Composition measurements show that the rainforest site was not significantly impacted by anthropogenic pollution, and this is confirmed by satellite retrievals of NO2 and HCHO. The dominant modulators of atmospheric chemistry at the rainforest site were therefore emissions of BVOCs and soil emissions of reactive nitrogen oxides. At the observed BVOC:NOx volume mixing ratio (~100 pptv/pptv), current chemical models suggest that daytime maximum OH concentrations should be ca. 105 radicals cm−3, but observed OH concentrations were an order of magnitude greater than this. We confirm, therefore, previous measurements that suggest that an unexplained source of OH must exist above tropical rainforest and we continue to interrogate the data to find explanations for this.

Published
2010

16. The kinetics of the gas-phase reactions of selected monoterpenes and cyclo-alkenes with ozone and the NO3 radical

Author

Christian Pfrang, George Marston, J. P. Lockhart, O. M. Mohamed, D. J. Stewart, S. H. Almabrok, and David R. Nutt

Subjects
chemistry.chemical_classification, Atmospheric Science, Cyclohexane, Alkene, Cyclohexene, Medicinal chemistry, chemistry.chemical_compound, Reaction rate constant, chemistry, Cyclooctene, Environmental Science(all), Dicyclopentadiene, Cyclopentene, Organic chemistry, General Environmental Science, Norbornene
Abstract

The relative rate method has been used to measure the room-temperature rate constants for the gas-phase reactions of ozone and NO3 with selected monoterpenes and cyclo-alkenes with structural similarities to monoterpenes. Measurements were carried out at 298 ± 2 K and 760 ± 10 Torr. The following rate constants (in units of 10−18 cm3 molecule−1 s−1) were obtained for the reaction with ozone: methyl cyclohexene (132 ± 17), terpinolene (1290 ± 360), ethylidene cyclohexane (223 ± 57), norbornene (860 ± 240), t-butyl isopropylidene cyclohexane (1500 ± 460), cyclopentene (543 ± 94), cyclohexene (81 ± 18), cyclooctene (451 ± 66), dicyclopentadiene (1460 ± 170) and α-pinene (107 ± 13). For the reaction with NO3 the rate constants obtained (in units of 10−12 cm3 molecule−1 s−1) were: methyl cyclohexene (7.92 ± 0.95), terpinolene (47.9 ± 4.0), ethylidene cyclohexane (4.30 ± 0.24), norbornene (0.266 ± 0.029), cyclohexene (0.540 ± 0.017), cyclooctene (0.513 ± 0.029), dicyclopentadiene (1.20 ± 0.10) and α-pinene (5.17 ± 0.62). Errors are quoted as the root mean square of the statistical error (95% confidence) and the quoted error in the rate constant for the reference compound. Combining these results with previous studies, new recommendations for the rate constants are presented. Molecular orbital energies were calculated for each alkene and the kinetic data are discussed in terms of the deviation from the structure–activity relationship obtained from the rate constants for a series of simple alkenes. Lifetimes with respect to key initiators of atmospheric oxidation have been calculated suggesting that the studied reactions play dominant roles in the night-time removal of these compounds from the atmosphere.

Published
2013

17. Atmospheric composition of West Africa: highlights from the AMMA international program

Author

Dominique Serça, Claire E. Reeves, J. E. Williams, Agnès Borbon, Francesco Cairo, Matthew J. Evans, Cedric F.A. Floquet, Alastair C. Lewis, Jennifer G. Murphy, M. D. Andrés-Hernández, Idir Bouarar, D. J. Stewart, Corinne Galy-Lacaux, Valérie Thouret, Dwayne E. Heard, Claire Delon, Daniel Stone, Roisin Commane, Trevor Ingham, E. Orlandi, David E. Oram, Marielle Saunois, Kathy S. Law, Niels Larsen, Joelle Bechara, Peter van Velthoven, Federico Fierli, Brice Barret, Catherine Liousse, Céline Mari, Carine D. Homan, Gérard Ancellet, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), TROPO - LATMOS, Laboratoire Atmosphères, Milieux, Observations Spatiales (LATMOS), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National de la Recherche Scientifique (CNRS), Institute of Environmental Physics [Bremen] (IUP), University of Bremen, Laboratoire Interuniversitaire des Systèmes Atmosphériques (LISA (UMR_7583)), Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Centre National de la Recherche Scientifique (CNRS), CNR Institute of Atmospheric Sciences and Climate (ISAC), Consiglio Nazionale delle Ricerche (CNR), School of Chemistry [Leeds], University of Leeds, School of Earth and Environment [Leeds] (SEE), Department of Physics, Faculty of Mathematics und Natural Sciences [Wuppertal], University of Wuppertal, Danish Meteorological Institute (DMI), National Centre for Atmospheric Science [York] (NCAS), University of York [York, UK], Department of Chemistry [University of Toronto], University of Toronto, Department of Chemistry [Reading], University of Reading (UOR), Royal Netherlands Meteorological Institute (KNMI), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), National Research Council of Italy | Consiglio Nazionale delle Ricerche (CNR), Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées, Laboratoire d'aérologie (LA), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Paris-Est Créteil Val-de-Marne - Paris 12 (UPEC UP12)-Institut national des sciences de l'Univers (INSU - CNRS)-Université Paris Diderot - Paris 7 (UPD7)-Centre National de la Recherche Scientifique (CNRS), School of the Environment, and National Centre for Atmospheric Science

Subjects
Wet season, Atmospheric Science, Atmospheric chemistry, 010504 meteorology & atmospheric sciences, 010501 environmental sciences, Monsoon, Atmospheric sciences, Convection, Urban pollution, 01 natural sciences, West africa, Atmospheric composition, Ozone, West Africa, Biomass burning, 0105 earth and related environmental sciences, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Biogenic emissions, 15. Life on land, 13. Climate action, Climatology, Biogenic emission, Environmental science, AMMA, Long-range transport
Abstract

The atmospheric composition of West Africa reflects the interaction of various dynamical and chemical systems (i.e. biogenic, urban, convective and long-range transport) with signatures from local to continental scales. Recent measurements performed during the African Monsoon Multidisciplinary Analyses (AMMA) observational periods in 2005 and 2006 provide new data which has allowed new insight into the processes within these systems that control the distribution of ozone and its precursors. Using these new data and recently published results, we provide an overview of these systems with a particular emphasis on ozone distributions over West Africa during the wet season. Copyright (C) 2010 Royal Meteorological Society

Published
2011

18. Nitrogen management is essential to prevent tropical oil palm plantations from causing ground-level ozone pollution

Author

A. R. MacKenzie, Mathew J. Evans, D. J. Stewart, S. F. Lim, Jambery Siong, Gavin Phillips, Pawel K. Misztal, Alastair C. Lewis, James Ryder, John A. Pyle, C. Di Marco, Martin Gallagher, C. E. Jones, James R. Hopkins, P. Di Carlo, Ben Langford, C. N. Hewitt, Sarah Moller, James Dorsey, Susan M. Owen, James D. Lee, Claire E. Reeves, David Fowler, David E. Oram, James B. McQuaid, Thomas A. M. Pugh, Eiko Nemitz, Paul S. Monks, and Ute Skiba

Subjects
Time Factors, Aircraft, Nitrogen, Nitrogen Dioxide, Rainforest, Arecaceae, Palm Oil, Nitric Oxide, Elaeis guineensis, Hemiterpenes, Ozone, Air Pollution, Pentanes, Tropical climate, Butadienes, Plant Oils, Peracetic Acid, Air quality index, Tropical Climate, Multidisciplinary, Geography, biology, Tropical agriculture, Agroforestry, business.industry, Agriculture, biology.organism_classification, Biofuel, Physical Sciences, Monoterpenes, Environmental science, business
Abstract

More than half the world's rainforest has been lost to agriculture since the Industrial Revolution. Among the most widespread tropical crops is oil palm ( Elaeis guineensis ): global production now exceeds 35 million tonnes per year. In Malaysia, for example, 13% of land area is now oil palm plantation, compared with 1% in 1974. There are enormous pressures to increase palm oil production for food, domestic products, and, especially, biofuels. Greater use of palm oil for biofuel production is predicated on the assumption that palm oil is an “environmentally friendly” fuel feedstock. Here we show, using measurements and models, that oil palm plantations in Malaysia directly emit more oxides of nitrogen and volatile organic compounds than rainforest. These compounds lead to the production of ground-level ozone (O 3 ), an air pollutant that damages human health, plants, and materials, reduces crop productivity, and has effects on the Earth's climate. Our measurements show that, at present, O 3 concentrations do not differ significantly over rainforest and adjacent oil palm plantation landscapes. However, our model calculations predict that if concentrations of oxides of nitrogen in Borneo are allowed to reach those currently seen over rural North America and Europe, ground-level O 3 concentrations will reach 100 parts per billion (10 9 ) volume (ppbv) and exceed levels known to be harmful to human health. Our study provides an early warning of the urgent need to develop policies that manage nitrogen emissions if the detrimental effects of palm oil production on air quality and climate are to be avoided.

Published
2010

19. Factors controlling the distribution of ozone in the West African lower troposphere during the AMMA (African Monsoon Multidisciplinary Analysis) wet season campaign

Author

Graham P. Mills, Ruth Purvis, Céline Mari, Claire E. Reeves, D. J. Stewart, David E. Oram, Jennifer G. Murphy, M. Saunois, Laboratoire d'aérologie (LAERO), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Observatoire Midi-Pyrénées (OMP), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Institut de Recherche pour le Développement (IRD)-Institut national des sciences de l'Univers (INSU - CNRS)-Centre National d'Études Spatiales [Toulouse] (CNES)-Centre National de la Recherche Scientifique (CNRS)-Météo-France -Centre National de la Recherche Scientifique (CNRS), CNRS-INSU, Centre National de la Recherche Scientifique (CNRS)-Observatoire Midi-Pyrénées (OMP), Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Météo France-Centre National d'Études Spatiales [Toulouse] (CNES)-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées

Subjects
Wet season, [PHYS.PHYS.PHYS-AO-PH]Physics [physics]/Physics [physics]/Atmospheric and Oceanic Physics [physics.ao-ph], Atmospheric Science, Ozone, 010504 meteorology & atmospheric sciences, Flux, 15. Life on land, 010501 environmental sciences, Monsoon, Atmospheric sciences, 01 natural sciences, Trace gas, Troposphere, chemistry.chemical_compound, Deposition (aerosol physics), chemistry, 13. Climate action, Climatology, NOx, 0105 earth and related environmental sciences
Abstract

Ozone and its precursors were measured on board the Facility for Airborne Atmospheric Measurements (FAAM) BAe 146 Atmospheric Research Aircraft during the monsoon season 2006 as part of the African Monsoon Multidisciplinary Analysis (AMMA) campaign. One of the main features observed in the west African boundary layer is the increase of the ozone mixing ratios from 25 ppbv over the forested area (south of 12° N) up to 40 ppbv over the Sahelian area. We employ a two-dimensional (latitudinal versus vertical) meteorological model coupled with an O3-NOx-VOC chemistry scheme to simulate the distribution of trace gases over West Africa during the monsoon season and to analyse the processes involved in the establishment of such a gradient. Including an additional source of NO over the Sahelian region to account for NO emitted by soils we simulate a mean NOx concentration of 0.7 ppbv at 16° N versus 0.3 ppbv over the vegetated region further south in reasonable agreement with the observations. As a consequence, ozone is photochemically produced with a rate of 0.25 ppbv h−1 over the vegetated region whilst it reaches up to 0.75 ppbv h−1 at 16° N. We find that the modelled gradient is due to a combination of enhanced deposition to vegetation, which decreases the ozone levels by up to 11 pbbv, and the aforementioned enhanced photochemical production north of 12° N. The peroxy radicals required for this enhanced production in the north come from the oxidation of background CO and CH4 as well as from VOCs. Sensitivity studies reveal that both the background CH4 and partially oxidised VOCs, produced from the oxidation of isoprene emitted from the vegetation in the south, contribute around 5–6 ppbv to the ozone gradient. These results suggest that the northward transport of trace gases by the monsoon flux, especially during nighttime, can have a significant, though secondary, role in determining the ozone gradient in the boundary layer. Convection, anthropogenic emissions and NO produced from lightning do not contribute to the establishment of the discussed ozone gradient.

Published
2009

20. Intercomparison of aircraft instruments on board the C-130 and Falcon 20 over southern Germany during EXPORT 2000

Author

Paul Stock, Helmut Ziereis, Hans Schlager, N. Brough, H. Barjat, J. Kent, D. J. Stewart, Stuart A. Penkett, Claire E. Reeves, Heidi Huntrieser, K. Dewey, Paul S. Monks, EGU, Publication, School of Environmental Sciences [Norwich], University of East Anglia [Norwich] (UEA), Meteorological Research Flight (MRF), United Kingdom Met Office [Exeter]-Defense Research Agency (DRA), Department of Chemistry, DLR Institut für Physik der Atmosphäre (IPA), and Deutsches Zentrum für Luft- und Raumfahrt [Oberpfaffenhofen-Wessling] (DLR)

Subjects
[SDU.OCEAN]Sciences of the Universe [physics]/Ocean, Atmosphere, Atmospheric Science, Flight level, Ozone, Meteorology, [SDU.OCEAN] Sciences of the Universe [physics]/Ocean, Atmosphere, O3, NOy, lcsh:QC1-999, NO, Plume, lcsh:Chemistry, CO, On board, chemistry.chemical_compound, lcsh:QD1-999, chemistry, Messvergleich, Range (aeronautics), Nitrogen oxide, lcsh:Physics, Air mass, Flight instruments
Abstract

International audience; In the summer 2000 EXPORT aircraft campaign (European eXport of Precursors and Ozone by long-Range Transport), two comprehensively instrumented research aircraft measuring a variety of chemical species flew wing tip to wing tip for a period of one and a quarter hours. During this interval a comparison was undertaken of the measurements of nitrogen oxide (NO), odd nitrogen species (NOy), carbon monoxide (CO) and ozone (O3). The comparison was performed at two different flight levels, which provided a 10-fold variation in the concentrations of both NO (10 to 1000 parts per trillion by volume (pptv)) and NOy (200 to over 2500 pptv). Large peaks of NO and NOy observed from the Falcon 20, which were at first thought to be from the exhaust of the C-130, were also detected on the 4 channel NOxy instrument aboard the C-130. These peaks were a good indication that both aircraft were in the same air mass and that the Falcon 20 was not in the exhaust plume of the C-130. Correlations and statistical analysis are presented between the instruments used on the two separate aircraft platforms. These were found to be in good agreement giving a high degree of correlation for the ambient air studied. Any deviations from the correlations are accounted for in the estimated inaccuracies of the instruments. These results help to establish that the instruments aboard the separate aircraft are reliably able to measure the corresponding chemical species in the range of conditions sampled and that data collected by both aircraft can be co-ordinated for purposes of interpretation.

Published
2003

21. Adenovirus-mediated wild-type p53 gene transfer in patients receiving chemotherapy for advanced non-small-cell lung cancer: results of a multicenter phase II study

Author

Martin Schuler, L. Laufman, D. J. Stewart, F. A. Shepherd, Christoph Huber, J. A. Horowitz, U. Gatzemeier, A. K. Stewart, C. Rochlitz, Roland Buhl, Friedrich Kommoss, Jürgen Kuball, R. Gralla, Mary Ann Fritz, Claus P. Heussel, J. L.P. De Greve, R. Herrmann, A. P. Perruchoud, Medical Imaging and Physical Sciences, and Vrije Universiteit Brussel

Subjects
Oncology, Adult, Male, Cancer Research, medicine.medical_specialty, Pathology, Lung Neoplasms, Paclitaxel, medicine.medical_treatment, Genetic Vectors, Phases of clinical research, Vinorelbine, Adenoviridae, Carboplatin, chemistry.chemical_compound, Internal medicine, Carcinoma, Non-Small-Cell Lung, Antineoplastic Combined Chemotherapy Protocols, medicine, Humans, Lung cancer, Aged, Cisplatin, Chemotherapy, business.industry, Genetic transfer, Genetic Therapy, Middle Aged, medicine.disease, Genes, p53, Survival Analysis, Regimen, Treatment Outcome, chemistry, Disease Progression, Female, business, medicine.drug
Abstract

PURPOSE: To study the additional benefit from adenoviral p53 gene therapy in patients undergoing first-line chemotherapy for advanced non–small-cell lung cancer (NSCLC). PATIENTS AND METHODS: Twenty-five patients with nonresectable NSCLC were enrolled in an open-label, multicenter phase II study of three cycles of regimen A, carboplatin (area under the curve, 6; day 1) plus paclitaxel (175 mg/m2, day 1), or regimen B, cisplatin (100 mg/m2, day 1) plus vinorelbine (25 mg/m2, days 1, 8, 15, and 22) in combination with intratumoral injection of 7.5 × 1012 particles of SCH 58500 (rAd/p53, day 1). Responses of individual tumor lesions were assessed after each cycle, and gene transfer was examined in posttreatment tumor biopsies using reverse transcriptase polymerase chain reaction. RESULTS: There was no difference between the response rate of lesions treated with p53 gene therapy in addition to chemotherapy (52% objective responses) and lesions treated with chemotherapy alone (48% objective responses). Subgroup analysis according to the chemotherapy regimens revealed evidence for increased mean local tumor regressions in response to additional p53 gene therapy in patients receiving regimen B, but not in patients receiving regimen A. There was no survival difference between the two chemotherapy regimens, and the median survival of the cohort was 10.5 months (1-year survival, 44%). Transgene expression was confirmed in tumor samples from 68% of patients, and toxicities attributable to gene therapy were mild to moderate. CONCLUSION: Intratumoral adenoviral p53 gene therapy appears to provide no additional benefit in patients receiving an effective first-line chemotherapy for advanced NSCLC.

Published
2001

22. An NCIC CTG phase I/pharmacokinetic study of the matrix metalloproteinase and angiogenesis inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin.

Author

R. Goel, E. Chouinard, D. J. Stewart, S. Huan, H. Hirte, S. Stafford, B. Waterfield, J. Roach, C. Lathia, V. Agarwal, R. Humphrey, W. Walsh, S. Matthews, and L. Seymour

Abstract

Background: This phase I study was performed to evaluate the safety, tolerability, and efficacy of the oral matrix metalloproteinase inhibitor BAY 12-9566 in combination with 5-fluorouracil/leucovorin in patients with advanced solid tumours, and to identify the maximum tolerated dose and the dose for use in future studies. Patients and methods: BAY 12-9566 and 5-fluorouracil/leucovorin were administered to 17 patients in 3 cohorts. Each patient served as his/her own control, with 5-fluorouracil being given alone on days 1–5 of cycle 1. In cohort 1, BAY 12-9566 at 800 mg p.o. b.i.d. was given with 350 mg/m2 5-fluorouracil/20 mg/m2 leucovorin × 5 days q28 days. In cohort 2, the BAY 12-9566 dose was reduced to 400 mg p.o. b.i.d., with the 5-fluorouracil/leucovorin doses remaining unchanged. Finally, in cohort 3, BAY 12-9566 400 mg bid was given with 5-fluorouracil 400 mg/m2/day. Patients were continued on therapy until unacceptable toxicity or tumour progression occurred. Pharmacokinetic analyses for both BAY 12-9566 and 5-fluorouracil were performed. Results: The maximum tolerated dose was 400 mg p.o. b.i.d. BAY 12-9566 plus 5-fluorouracil/leucovorin at 400 mg/m2/day and 20 mg/m2/day, respectively. Thrombocytopenia necessitated a decrease of the dose of BAY 12-9566 by 50% from cohort 1 to cohort 2. Two dose-limiting toxicities occurred in cohort 3 consisting of neutropenic fever, and ileitis, causing severe diarrhea. Of 17 patients treated on study, 7 of 14 patients evaluable for response achieved stable disease. Pharmacokinetic analysis suggested there was no interaction between BAY 12-9566 and 5-fluorouracil. Conclusions: BAY 12-9566 400 mg bid and 5-fluorouracil 350 mg/m2 plus leucovorin 20 mg/m2 can be co-administered. Although there is some evidence of a clinical interaction, there is no apparent pharmacokinetic interaction. Future studies with these 2 types of agents administered in combination are warranted. [ABSTRACT FROM AUTHOR]

Published
2005
Full Text
View/download PDF

Catalog

Books, media, physical & digital resources
See catalog results