893 research outputs found

    Faculty attitudes toward technology -based distance education at the University of Nevada, Las Vegas

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    The purpose of this study was to survey the attitudes of the teaching faculty of the University of Nevada, Las Vegas toward technology-based distance education, and to determine if the reported attitudes fell into the six factors of the Attitudinal Differences Model; A survey of the teaching faculty was done in the fall of 1997, and again in the spring of 1998, resulting in a 28.7% response rate. Factor analysis extracted three uncorrelated factors (Vision, Effectiveness, Barriers) which accounted for 56% of the variance in faculty self-reported attitudes. The seven research questions guiding this study were addressed, when appropriate, in reference to these extracted attitude factors; Faculty responding (N = 188) to the survey hold a slightly positive attitude toward distance education (median score = 3.24) without regard to age, gender, number of years teaching or tenure. Membership in a particular college was significant, at .05 alpha, only with the \u27Barriers\u27 attitude factor. The College of Education (most positive attitude) was significantly different from the College of Liberal Arts (more negative attitude) and the College of Science (most negative attitude); Support (administrative and technical) and training were found to be important, yet lacKing Incentives focused on reward systems and student needs (especially in rural Nevada), while deterrents focused on lack of knowledge and questions of effectiveness. Peers were the greatest and most influential source of distance education information, and experience as a student or as an instructor was significantly related, at .05 alpha, only to the \u27Barriers\u27 attitude factor; The Attitudinal Differences Model combines six interrelated elements to explain attitude. This study supports ADM elements exposure, peer influence, incentives and opportunity, finding them to be part of the operating environment that shapes the attitude, rather than an integral aspect of attitude itself. Elements \u27Need\u27 and \u27Barriers\u27 were found to be the extracted factors \u27Vision\u27 and \u27Barriers\u27, integral aspects of attitude itself; Overall, there is faculty interest, as evidenced by 66% of respondents willing to teach a distance education class in the future; however, there is a lack of: (1) reliable information, (2) administrative and technical support, (3) faculty development opportunities or programs, and (4) both extrinsic and intrinsic rewards

    Dynamo Regimes with a Nonhelical Forcing

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    A three-dimensional numerical computation of magnetohydrodynamic dynamo behavior is described. The dynamo is mechanically forced with a driving term of the Taylor-Green type. The magnetic field development is followed from negligibly small levels to saturated values that occur at magnetic energies comparable to the kinetic energies. Although there is locally a nonzero helicity density, there is no overall integrated helicity in the system. Persistent oscillations are observed in the saturated state for not-too-large mechanical Reynolds numbers, oscillations in which the kinetic and magnetic energies vary out of phase but with no reversal of the magnetic field. The flow pattern exhibits considerable geometrical structure in this regime. As the Reynolds number is increased, the oscillations disappear and the energies become more nearly stationary, but retain some unsystematically fluctuating turbulent time dependence. The regular geometrical structure of the fields gives way to a more spatially disordered distribution. The injection and dissipation scales are identified, and the different components of energy transfer in Fourier space are analyzed, particularly in the context of clarifying the role played by different flow scales in the amplification of the magnetic field. We observe that small and large scales interact and contribute to the dynamo process

    Dynamo regimes with a nonhelical forcing

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    11 pagesInternational audienceA three-dimensional numerical computation of magnetohydrodynamic dynamo behavior is described. The dynamo is mechanically forced with a driving term of the Taylor-Green type. The magnetic field development is followed from negligibly small levels to saturated values that occur at magnetic energies comparable to the kinetic energies. Although there is locally a nonzero helicity density, there is no overall integrated helicity in the system. Persistent oscillations are observed in the saturated state for not-too-large mechanical Reynolds numbers, oscillations in which the kinetic and magnetic energies vary out of phase but with no reversal of the magnetic field. The flow pattern exhibits considerable geometrical structure in this regime. As the Reynolds number is increased, the oscillations disappear and the energies become more nearly stationary, but retain some unsystematically fluctuating turbulent time dependence. The regular geometrical structure of the fields gives way to a more spatially disordered distribution. The injection and dissipation scales are identified, and the different components of energy transfer in Fourier space are analyzed, particularly in the context of clarifying the role played by different flow scales in the amplification of the magnetic field. We observe that small and large scales interact and contribute to the dynamo process

    Loss of the Histone Pre-mRNA Processing Factor Stem-Loop Binding Protein in Drosophila Causes Genomic Instability and Impaired Cellular Proliferation

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    BACKGROUND:Metazoan replication-dependent histone mRNAs terminate in a conserved stem-loop structure rather than a polyA tail. Formation of this unique mRNA 3' end requires Stem-loop Binding Protein (SLBP), which directly binds histone pre-mRNA and stimulates 3' end processing. The 3' end stem-loop is necessary for all aspects of histone mRNA metabolism, including replication coupling, but its importance to organism fitness and genome maintenance in vivo have not been characterized. METHODOLOGY/PRINCIPAL FINDINGS:In Drosophila, disruption of the Slbp gene prevents normal histone pre-mRNA processing and causes histone pre-mRNAs to utilize the canonical 3' end processing pathway, resulting in polyadenylated histone mRNAs that are no longer properly regulated. Here we show that Slbp mutants display genomic instability, including loss of heterozygosity (LOH), increased presence of chromosome breaks, tetraploidy, and changes in position effect variegation (PEV). During imaginal disc growth, Slbp mutant cells show defects in S phase and proliferate more slowly than control cells. CONCLUSIONS/SIGNIFICANCE:These data are consistent with a model in which changing the 3' end of histone mRNA disrupts normal replication-coupled histone mRNA biosynthesis and alters chromatin assembly, resulting in genomic instability, inhibition of cell proliferation, and impaired development
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