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1.
Phys Rev Lett ; 103(21): 215002, 2009 Nov 20.
Artigo em Inglês | MEDLINE | ID: mdl-20366044

RESUMO

A nonaxisymmetric stable magnetohydrodynamic (MHD) equilibrium within a prolate cylindrical conducting boundary has been produced experimentally. It has m=1 azimuthal symmetry, helical distortion, and flat lambda profile, all in agreement with the computed magnetically relaxed minimum magnetic energy Taylor state. Despite varied initial conditions determined by two helicity injectors on the device, this same equilibrium consistently emerges as the final state. These results therefore describe a new example of self-organization in an MHD plasma.

2.
Phys Rev Lett ; 103(16): 165005, 2009 Oct 16.
Artigo em Inglês | MEDLINE | ID: mdl-19905705

RESUMO

Good alignment of the magnetic field line pitch angle with the mode structure of an external resonant magnetic perturbation (RMP) field is shown to induce modulation of the pedestal electron pressure p(e) in high confinement high rotation plasmas at the DIII-D tokamak with a shape similar to ITER, the next step tokamak experiment. This is caused by an edge safety factor q95 resonant enhancement of the thermal transport, while in contrast, the RMP induced particle pump out does not show a significant resonance. The measured p(e) reduction correlates to an increase in the modeled stochastic layer width during pitch angle variations matching results from resistive low rotation plasmas at the TEXTOR tokamak. These findings suggest a field line pitch angle resonant formation of a stochastic magnetic edge layer as an explanation for the q95 resonant character of type-I edge localized mode suppression by RMPs.

3.
J Sch Health ; 51(4): 219-22, 1981 Apr.
Artigo em Inglês | MEDLINE | ID: mdl-6908929

RESUMO

PIP: The Family Life and Human Development (Sex Education) program is now fully implemented in 99.5% of Prince George's County Public Schools. The program is credited with better than 98% parental acceptance and student participation. The administrative guidelines and program supervision are crucial to the program's success. The program was developed to be in compliance with the Maryland State Board of Education Bylaw 13.03.03.01 that requires that sex education be offered. Prior to program implementation, the guidelines were written, parents were involved, and teachers and administrators were trained. All instruction is organized around 3 areas of focus: interpersonal relationships; physiological and personality changes of puberty; and advanced physiology and psychology of human sexual behavior. The major limitation of the program is that in grades 9-12 when such subjects as contraception, abortion, homosexuality and premarital intercourse can be discussed, only a small percentage of the student population are able to enroll each year. The reason for the low percentage include lack of funds to hire additional teachers, limited time due to 1/2 day work/study teachers, and the elective classification of the program. Before a teacher is permitted to teach any aspect of the program that deals with the reproductive system or any potentially sensitive area of sexuality, he/she must 1st meet certain established criteria.^ieng


Assuntos
Educação Sexual , Adolescente , Criança , Currículo , Objetivos , Humanos , Maryland , Instituições Acadêmicas , Comportamento Sexual/fisiologia , Ensino
4.
J Nurs Educ ; 38(5): 208-14, 1999 May.
Artigo em Inglês | MEDLINE | ID: mdl-10438094

RESUMO

Many colleges and universities currently are implementing service learning as an educational strategy into their curricula. The goal of service learning is a dynamic partnership between educational institutions and communities resulting in the mutual benefits of service and learning. Although service learning has significance for teaching nursing students, educators must differentiate service learning from clinical practicum. This article provides a definition of service learning, identifies the relevance of service learning for nursing education, presents an example of service learning integrated into a nursing course, and evaluates service learning as a methodology for teaching group collaboration and research skills. Student surveys, a focus group, and community partner evaluations indicated service learning contributed to the development of group collaboration and research skills among baccalaureate nursing students. To enhance faculty, student, and community partner satisfaction with service learning, instructors should clearly define service learning experiences for a specific setting and offer structured guidance that does not interfere with student decision-making.


Assuntos
Enfermagem em Saúde Comunitária/educação , Comportamento Cooperativo , Pesquisa em Enfermagem/educação , Redes Comunitárias , Currículo , Grupos Focais , Humanos , Estudantes de Enfermagem , Ensino/métodos
5.
Phys Rev Lett ; 100(20): 205001, 2008 May 23.
Artigo em Inglês | MEDLINE | ID: mdl-18518542

RESUMO

The plasma in tokamaks often exhibits a relaxation oscillation called the edge-localized mode (ELM), which is generally attributed to MHD instability driven by strong gradients at the plasma boundary. It is shown here that field-aligned currents flowing just outside the boundary may also play a role in the ELM process. The poloidal perturbation magnetic field during ELMs in the DIII-D tokamak calculated from measured currents can reproduce prominent observed features, including a narrow magnetic structure at the outboard midplane similar to filaments observed earlier in DIII-D and NSTX.

6.
Phys Rev Lett ; 101(19): 195005, 2008 Nov 07.
Artigo em Inglês | MEDLINE | ID: mdl-19113280

RESUMO

We present the first evidence for the existence of a neoclassical toroidal rotation driven in a direction counter to the plasma current by nonaxisymmetric, nonresonant magnetic fields. At high beta and with large injected neutral beam momentum, the nonresonant field torque slows down the plasma toward the neoclassical "offset" rotation rate. With small injected neutral beam momentum, the toroidal rotation is accelerated toward the offset rotation, with resulting improvement in the global energy confinement time. The observed magnitude, direction, and radial profile of the offset rotation are consistent with neoclassical theory predictions.

7.
Phys Rev Lett ; 88(25 Pt 1): 255002, 2002 Jun 24.
Artigo em Inglês | MEDLINE | ID: mdl-12097092

RESUMO

The transition from the low to the high mode of plasma confinement ( L-H transition) is studied in the DIII-D by an experimental technique which allows an arbitrarily slow transition. During an initial transition, periodic turbulent instability bursts are observed near the separatrix which inhibit the full transition. These bursts are damped by self-generated shear flows, and a predator-prey-type relationship is shown to give a good description of the data. As the neutral-beam power is raised, the oscillations change to type III edge localized modes. Another transition then leads to a quiet H mode.

8.
Phys Rev Lett ; 92(23): 235003, 2004 Jun 11.
Artigo em Inglês | MEDLINE | ID: mdl-15245164

RESUMO

A stochastic magnetic boundary, produced by an applied edge resonant magnetic perturbation, is used to suppress most large edge-localized modes (ELMs) in high confinement (H-mode) plasmas. The resulting H mode displays rapid, small oscillations with a bursty character modulated by a coherent 130 Hz envelope. The H mode transport barrier and core confinement are unaffected by the stochastic boundary, despite a threefold drop in the toroidal rotation. These results demonstrate that stochastic boundaries are compatible with H modes and may be attractive for ELM control in next-step fusion tokamaks.

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