196,925 research outputs found
Glycemic index and glycemic load: Application in observational studies and association with hepatocellular carcinoma risk. Meaningful or error prone?
No full textmissin
Study of trapping effect on ion-acoustic solitary waves based on a fully kinetic simulation approach
No full textA fully kinetic simulation approach, treating each plasma component based on the Vlasov equation, is adopted to study the disintegration of an initial density perturbation into a number of ion-acoustic solitary waves (IASWs) in the presence of the trapping effect of electrons. The nonlinear fluid theory developed by Schamel [Plasma Phys. 13, 491 (1971); J. Plasma Phys. 7, 1 (1972); Plasma Phys. 14, 905 (1972); J. Plasma Phys. 9, 377 (1973); Phys. Scr. 20, 306 (1979)] has identified three separate regimes of ion-acoustic solitary waves based on the trapping parameter. Here, the disintegration process and the resulting self-consistent IASWs are studied in a wide range of trapping parameters covering all the three regimes continuously. The dependency of features such as the time of disintegration, the number, speed, and size of IASWs on the trapping parameter are focused upon. It is shown that an increase in this parameter slows down the propagation of IASWs while decreases their sizes in the phase space. These features of IASWs tend to saturate for large values of trapping parameters. The disintegration time shows a more complicated behavior than what was predicted by the theoretical approach. Also for the case of trapping parameters bigger than one, propagation of IASWs is observed in contrast with the theoretical predictions. The kinetic simulation results unveil a smooth and well-defined dependency of solitary waves' features on the trapping parameter, showing the possibility of bridging all the three regimes. Finally, it is shown that for β around zero, the electron phase space structure of the accompanying vortex stays symmetric. The effect of the electron-to-ion temperature ratio on the disintegration and the propagation of IASWs are considered as a benchmarking test of the simulation code (in the nonlinear regime
Dr. Duane M. Jackson, Morehouse College, July 2011
No full textThis video is a conversation with Dr. Duane M. Jackson. Dr. Jackson talks about his paper, "Recall and the Serial Position Effect: The Role of Primacy and Recency on Accounting Students' Performance." Jackie Daniel, AUC Woodruff Library, is the interviewer
Scattering of electron holes in the context of ion-acoustic regime
No full textMutual collisions between ion-acoustic solitary waves are studied based on a fully kinetic simulation approach. Two cases, small and large relative
velocities, are studied, and the effect of trapped electron population on the collision process is focused upon. It is shown that, for the case of small
relative velocity, the repelling force between the trapped populations of electrons results in scattering of electron holes. However, this phenomenon
cannot be witnessed if the relative velocity is considerably high since the impact of trapped population remains very wea
"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States" By M. Carey.
No full text"Reflections on the subject of Emigration from Europe with a view to Settlement in the United States: containing bried sketches of the moral and political character of those states.
By M. Carey, member of the American philosophical, and of the American Antiquarian Society, and author of The Olive Branch, Cindiciae Hibernicae, essays on banking, on political economy, and on internal improvement.
To which are now added the English editor's comments on the subject; together with Important Advice to Emigrants, and Cautions Against Impositions Practiced in the Outports
Fully kinetic simulation study of ion-acoustic solitons in the presence of trapped electrons
No full textThe nonlinear fluid theory developed by Schamel suggests a modified KdV equation to describe the temporal evolution of ion acoustic (IA) solitons in the presence of trapped electrons. The validity of this theory is studied here by verifying solitons' main characteristic, i.e., stability against successive mutual collisions. We have employed a kinetic model as a more comprehensive theory than the fluid one, and utilized a fully kinetic simulation approach (both ions and electrons are treated based on the Vlasov equation). In the simulation approach, these solitons are excited self-consistently by employing the nonlinear process of IA solitons formation from an initial density perturbation (IDP). The effect of the size of IDPs on the chain formation is proved by the simulation code as a benchmark test. It is shown that the IA solitons, in the presence of trapped electrons, can retain their features (both in spatial and velocity direction) after successive mutual collisions. The collisions here include encounters of IA solitons with the same trapping parameter, while differing in size. Kinetic simulation results reveal a complicated behavior during a collision between IA solitons in contrast to the fluid theory predictions and simulations. In the range of parameters considered here, two oppositely propagating solitons rotate around their collective center in the phase space during a collision, independent of their trapping parameters. Furthermore, they exchange some portions of their trapped population
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Simulation study of overtaking of ion-acoustic solitons in the fully kinetic regime
No full textThe overtaking collisions of ion-acoustic solitons in the presence of trapping effects of electrons are studied based on a fully kinetic simulation approach. The method is able to provide all the kinetic details of the process alongside the fluid-level quantities self consistently. Solitons are produced naturally by utilizing the chain formation phenomenon, and then are arranged in a new simulation box to test the different scenarios of overtaking collisions. Three achievements are reported here. First, simulations prove the long-time life span of the ion-acoustic solitons in the presence of trapping effect of electrons (kinetic effects), which serves as the benchmark of the simulation code. Second, their stability against overtaking mutual collisions is established by creating collisions between solitons with different number and shapes of trapped electrons, i.e., different trapping parameter. Finally, details of solitons during collisions for both ions and electrons are provided on both fluid and kinetic levels. These results show that on the kinetic level, trapped electron population accompanying each of the solitons are exchanged between the solitons during the collision. Furthermore, the behavior of electron holes accompanying solitons contradicts the theory about the electron holes interaction developed based on kinetic theory. They also show behaviors much different from other electron holes witnessed in processes such as nonlinear Landau damping (Bernstein-Greene-Kruskal -BGK- modes) or beam-plasma interaction (like two-beam instability
Dr. Glendon Swarthout
No full textHosted by Roger M. Busfield, MSU Assistant Professor of Speech and Theater, Meet the Author is designed to introduce a general audience to a contemporary author and their work through in-depth interviews. This episode features a conversation between Dr. Glendon Swarthout, prolific author and English professor at MSU, and assistant professors Sam S. Baskett and Theodore B. Strandness
Dietary intake of total polyphenol and polyphenol classes and the risk of colorectal cancer in the European Prospective Investigation into Cancer and Nutrition (EPIC) cohort
No full textThe coordination of EPIC is financially supported by the European Commission (DG-SANCO) and the International Agency for Research on Cancer. European Research Council (ERC-2009-AdG 232997); Health Research Fund (FIS): PI13/00061 to Granada; PI13/01162 to EPICMurcia, Regional Governments of Andalucı´a, Asturias, Basque Country, Murcia and Navarra, AGAUR - Generalitat de Catalunya (exp. 2014 SGR 726), The Health Research Funds RD12/0036/0018, cofunded by European Regional Development Fund (ERDF) ‘‘A way to build Europe (Spain);RZ-R was supported by the ‘‘Miguel Servet’’ program (CP15/00100) from the Institute of Health Carlos III and European Social Fund (ESF). (...)Zamora-Ros, R., Cayssials, V., Jenab, M., Rothwell, J.A., Fedirko, V., Aleksandrova, K., Tjønneland, A., Kyrø, C., Overvad, K., Boutron-Ruault, M.-C., Carbonnel, F., Mahamat-Saleh, Y., Kaaks, R., Kühn, T., Boeing, H., Trichopoulou, A., Valanou, E., Vasilopoulou, E., Masala, G., Pala, V., Panico, S., Tumino, R., Ricceri, F., Weiderpass, E., Lukic, M., Sandanger, T.M., Lasheras, C., Agudo, A., Sánchez, M.-J., Amiano, P., Navarro, C., Ardanaz, E., Sonestedt, E., Ohlsson, B., Nilsson, L.M., Rutegård, M., Bueno-de-Mesquita, B., Peeters, P.H., Khaw, K.-T., Wareham, N.J., Bradbury, K., Freisling, H., Romieu, I., Cross, A.J., Vineis, P., Scalbert, A
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