Mathematical Model and Analysis of Drug Addiction among Adolescent’s Populace in Nigeria

Drug addiction has become a menace especially among adolescents which has massively contributed to the social vices perpetrated by youths in Nigeria. We constructed a five-compartment model to explain the transmission dynamics of addiction leading to a non-linear deterministic equation. The next generation approach was employed to obtain the basic reproduction number (R_0). The drug free equilibrium point was obtained and showed to be locally asymptotically stable when the threshold quantity is less than one. A suitable Lyapunov function was constructed for the global stability which was found to be globally asymptotically stable. Sensitivity analysis was conducted to ascertain the behavior of the various parameters on the threshold quantity to deduce a suitable intervention strategy. Numerical simulations are carried out, the analysis is discussed, and the results are presented in graphical form. Keywords: Addiction, model, drug, stability, basic reproduction number, sensitivity analysis

Supervision and Scholarly Writing: Writing to Learn - Learning to Write

This paper describes an action research project on postgraduate students’ scholarly writing in which I employed reflective approaches to examine and enhance my postgraduate supervisory practice. My reflections on three distinct cycles of supervision illustrate a shift in thinking about scholarly writing and an evolving understanding of how to support postgraduate students’ writing. These understandings provide the foundation for a future-oriented fourth cycle of supervisory practice, which is characterised by three principles, namely the empowerment of students as writers, the technological context of contemporary writing, and ethical issues in writing

Toroidally Asymmetric Distributions of Hydrocarbon (CD) Emission and Chemical Sputtering Sources in DIII-D

Measurements in DIII-D show that the carbon chemical sputtering sources along the inner divertor and center post are toroidally periodic and highest at the upstream tile edge. Imaging with a tangentially viewing camera and visible spectroscopy were used to monitor the emission from molecular hydrocarbons (CH/CD) at 430.8 nm and deuterium neutrals in attached and partially detached divertors of low-confinement mode plasmas. In contrast to the toroidally periodic CD distribution, emission from deuterium neutrals was observed to be toroidally symmetric along the inner strike zone. The toroidal distribution of the measured tile surface temperature in the inner divertor correlates with that of the CD emission, suggesting larger parallel particle and heat fluxes to the upstream tile edge, either due to toroidal tile gaps or height steps between adjacent tiles

Doppler coherence imaging and tomography of flows in tokamak plasmas

This article describes the results of spatial heterodyne Doppler "coherence imaging" of carbon ion flows in the divertor region of the DIII-D tokamak. Spatially encoded interferometric projections of doubly ionized carbon emission at 465 nm have been demodulated and tomographically inverted to obtain the spatial distribution of the carbon ion parallel flow and emissivity. The operating principles of the new instruments are described, and the link between measured properties and line integrals of the flow field are established. An iterative simultaneous arithmetic reconstruction procedure is applied to invert the interferometric phase shift projections, and the reconstructed parallel flow field amplitudes are found to be in reasonable agreement with UEDGE modeling

On the acoustic diffraction by the edges of benthic shells

Author Posting. © Acoustical Society of America, 2004. This article is posted here by permission of Acoustical Society of America for personal use, not for redistribution. The definitive version was published in Journal of the Acoustical Society of America 116 (2004): 239-244, doi:10.1121/1.1675813.Recent laboratory measurements of acoustic backscattering by individual benthic shells have isolated the edge-diffracted echo from echoes due to the surface of the main body of the shell. The data indicate that the echo near broadside incidence is generally the strongest for all orientations and is due principally to the surface of the main body. At angles well away from broadside, the echo levels are lower and are due primarily to the diffraction from the edge of the shell. The decrease in echo levels from broadside incidence to well off broadside is shown to be reasonably consistent with the decrease in acoustic backscattering from normal incidence to well off normal incidence by a shell-covered seafloor. The results suggest the importance of the edge of the shell in off-normal-incidence backscattering by a shell-covered seafloor. Furthermore, when considering bistatic diffraction by edges, there are implications that the edge of the shell (lying on the seafloor) can cause significant scattering in many directions, including at subcritical angles.This research was supported by the U.S. Office of Naval Research (Grant No. N00014-02-1-0095) and the Woods Hole Oceanographic Institution (WHOI), Woods Hole, MA

Easing into the Academy: Using Technology to Foster Cross-Institutional Critical Friendships

This article addresses the ways in which early career teacher educators can support each other as they enter the academic community. By utilizing technology as an instrument to engage in a cross-country critical friendship, the authors were able to engage in a dialogue that grew out of mutual interests and concerns. Through critical reflection, they were able to address the question: How can we, two early-career teacher educators, push ourselves and one another to more critically examine our teaching practices? In doing so, each “new educator” grew more confident in claiming one\u27s voice as a sustainable critical friendship emerged

Edge localized mode control with an edge resonant magnetic perturbation

A low amplitude (δbr∕BT=1 part in 5000) edge resonantmagnetic field perturbation with toroidalmode number n=3 and poloidal mode numbers between 8 and 15 has been used to suppress most large type I edge localized modes(ELMs) without degrading core plasma confinement. ELMs have been suppressed for periods of up to 8.6 energy confinement times when the edge safety factor q95 is between 3.5 and 4. The large ELMs are replaced by packets of events (possibly type II ELMs) with small amplitude, narrow radial extent, and a higher level of magnetic field and density fluctuations, creating a duty cycle with long “active” intervals of high transport and short “quiet” intervals of low transport. The increased transport associated with these events is less impulsive and slows the recovery of the pedestal profiles to the values reached just before the large ELMs without the n=3 perturbation. Changing the toroidal phase of the perturbation by 60° with respect to the best ELM suppression case reduces the ELM amplitude and frequency by factors of 2–3 in the divertor, produces a more stochastic response in the H-mode pedestal profiles, and displays similar increases in small scale events, although significant numbers of large ELMs survive. In contrast to the best ELM suppression case where the type I ELMs are also suppressed on the outboard midplane, the midplane recycling increases until individual ELMs are no longer discernable. The ELM response depends on the toroidal phase of the applied perturbation because intrinsic error fields make the target plasma nonaxisymmetric, and suggests that at least some of the variation in ELM behavior in a single device or among different devices is due to differences in the intrinsic error fields in these devices. These results indicate that ELMs can be suppressed by small edge resonantmagnetic field perturbations. Extrapolation to next-step burning plasma devices will require extending the regime of operation to lower collisionality and understanding the physical mechanism responsible for the ELM suppression.This work was funded by the U.S. Department of Energy under Grant Nos. DE-FC02-04ER54698, DE-FG02- 04ER54758, DE-FG03-01ER54615, W-7405-ENG-48, DEFG03-96ER54373, DE-FG02-89ER53297, DE-AC05- 00OR22725, and DE-AC04-94AL85000

Preparation for propagation and absorption experiments in MTX

Preparatory calculations of microwave transmission through the MTX access duct, propagation of the waves through the plasma and the resulting power deposition profile on a calorimeter located on the tokamak inside wall have been performed. The microwave transmission calculations include the relative phase slippage of waveguide modes in the duct to determine the spatial structure of the wavefront at the duct exist. Ray-tracing calculations show substantial spreading of the beam in the poloidal direction at densities above 1.5 /times/ 10/sup 20/ m/sup /minus/3/, well within the range of the experiments. Initial experiments with low or high toroidal field (cyclotron resonance outside the plasma) will investigate both diffraction and refraction effects, without absorption. Estimates of the fractional absorption of the beam in the initial experiments with the cyclotron resonance at the plasma axis have also been made. 4 refs., 3 figs