50 research outputs found
Plasmas and Controlled Nuclear Fusion
Contains reports on ten research projects split into three sections.National Science Foundation (Grant GK-2581
Applied Plasma Research
Contains research objectives and reports on three research projects.National Science Foundation (Grant GK-2581)Joint Services Electronics Program under Contract DA 28-043-AMC-02536(E
Plasmas and Controlled Nuclear Fusion
Contains research objectives and reports on three research projects.National Science Foundation (Grant GK-1165)National Science Foundation (Grant GK-57
Plasmas and Controlled Nuclear Fusion
Contains research objectives and reports on three research projects.National Science Foundation (Grant GK-1165
Media reporting of tenofovir trials in Cambodia and Cameroon
BACKGROUND: Two planned trials of pre-exposure prophylaxis tenofovir in Cambodia and Cameroon to prevent HIV infection in high-risk populations were closed due to activist pressure on host country governments. The international news media contributed substantially as the primary source of knowledge transfer regarding the trials. We aimed to characterize the nature of reporting, specifically focusing on the issues identified by media reports regarding each trial. METHODS: With the aid of an information specialist, we searched 3 electronic media databases, 5 electronic medical databases and extensively searched the Internet. In addition we contacted stakeholder groups. We included media reports addressing the trial closures, the reasons for the trial closures, and who was interviewed. We extracted data using content analysis independently, in duplicate. RESULTS: We included 24 reports on the Cambodian trial closure and 13 reports on the Cameroon trial closure. One academic news account incorrectly reported that it was an HIV vaccine trial that closed early. The primary reasons cited for the Cambodian trial closure were: a lack of medical insurance for trial related injuries (71%); human rights considerations (71%); study protocol concerns (46%); general suspicions regarding trial location (37%) and inadequate prevention counseling (29%). The primary reasons cited for the Cameroon trial closure were: inadequate access to care for seroconverters (69%); participants not sufficiently informed of risks (69%); inadequate number of staff (46%); participants being exploited (46%) and an unethical study design (38%). Only 3/23 (13%) reports acknowledged interviewing research personnel regarding the Cambodian trial, while 4/13 (30.8%) reports interviewed researchers involved in the Cameroon trial. CONCLUSION: Our review indicates that the issues addressed and validity of the media reports of these trials is highly variable. Given the potential impact of the media in formulation of health policy related to HIV, efforts are needed to effectively engage the media during periods of controversy in the HIV/AIDS epidemic
SIMULATION NUMÉRIQUE DE L'INTERACTION D'UNE ONDE INTENSE AVEC UN PLASMA MONODIMENSIONNEL
On étudie l'interaction d'une onde monochromatique de grande amplitude avec un plasma d'électrons monodimensionnel au moyen d'un modèle de simulation numérique. La fréquence de l'onde extérieure est prise égale à deux fois la fréquence plasma. Une instabilité paramétrique prend naissance à partir d'un certain seuil lorsqu'on tient compte de l'inhomogénéité spatiale du champ extérieur imposé.Numerical calculations have been carried out for simulation of high amplitude monochromatic wave electron plasma interaction, using a one dimensional model. External wave frequency is twice plasma frequency. Parametric instability grows up from a certain threshold when taking into account spatial inhomogeneity of the applied external field
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Convective transport in laser target plasmas
The role of guiding-center corrections in convective transport of electron energy is examined with a simple numerical model. At 10/sup 16/W cm/sup -2/ with a 60-..mu..m spot and a 10.6-..mu..m wavelength laser, the Righi-Leduc term is observed to have little effect on transport in a calculation with the thermal flux limited to the free-streaming value