9,457 research outputs found

    Very high resolution UV and X-ray spectroscopy and imagery of solar active regions

    Get PDF
    A scientific investigation of the physics of the solar atmosphere, which uses the techniques of high resolution soft X-ray spectroscopy and high resolution UV imagery, is described. The experiments were conducted during a series of three sounding rocket flights. All three flights yielded excellent images in the UV range, showing unprecedented spatial resolution. The second flight recorded the X-ray spectrum of a solar flare, and the third that of an active region. A normal incidence multi-layer mirror was used during the third flight to make the first astronomical X-ray observations using this new technique

    Toiling in Factory and on Farm: An Employer-Friendly Approach to the Compensability of Donning and Doffing Activities Under the FLSA

    Get PDF
    No realm of employment litigation has been more active in recent years than class action lawsuits under the Fair Labor Standards Act (FLSA). Although the FLSA was originally enacted to help those who toiled in factories and on farms obtain a fair day’s pay for a fair day’s work, it continues to haunt unwary employers nearly seventy years later. This Note attempts to resolve those problems through the proposition of a single, uniform, and employer-friendly standard for donning and doffing claims arising under the FLSA. Specifically, this Note argues that courts should construe the “integral and indispensable” test narrowly to protect employers from compensation claims for relatively effortless activities while also exposing them to litigation for work that is essential to completion of the principal activity, as contemplated by early labor standard advocates. This ensures that legitimate claims for uncompensated work time are fully covered by the FLSA and that frivolous suits fall by the wayside

    Rocket studies of solar corona and transition region

    Get PDF
    The XSST (X-Ray Spectrometer/Spectrograph Telescope) rocket payload launched by a Nike Boosted Black Brant was designed to provide high spectral resolution coronal soft X-ray line information on a spectrographic plate, as well as time resolved photo-electric records of pre-selected lines and spectral regions. This spectral data is obtained from a 1 x 10 arc second solar region defined by the paraboloidal telescope of the XSST. The transition region camera provided full disc images in selected spectral intervals originating in lower temperature zones than the emitting regions accessible to the XSST. A H-alpha camera system allowed referencing the measurements to the chromospheric temperatures and altitudes. Payload flight and recovery information is provided along with X-ray photoelectric and UV flight data, transition camera results and a summary of the anomalies encountered. Instrument mechanical stability and spectrometer pointing direction are also examined

    Dynamic evolution of the source volumes of gradual and impulsive solar flare emissions

    Get PDF
    This study compares flare source volumes inferred from impulsive hard X-rays and microwaves with those derived from density sensitive soft X-ray line ratios in the O VII spectrum. The data for this study were obtained with the SMM Hard X-Ray Burst Spectrometer, Earth-based radio observatories, and the SOLEX-B spectrometer on the P78-1 satellite. Data were available for the flares of 1980 April 8, 1980 May 9, and 1981 February 26. The hard X-ray/microwave source volume is determined under the assumption that the same electron temperature or power law index characterizes both the source of hard X-rays and the source of microwaves. The O VII line ratios yield the density and volume of the 2 X 10 to the 6th K plasma. For all three flares, the O VII source volume is found to be smallest at the beginning of the flare, near the time when the impulsive hard X-ray/microwave volume reaches its first maximum. At this time, the O VII volume is three to four orders of magnitude smaller than that inferred from the hard X-ray/microwave analysis. Subsequently, the O VII source volume increases by one or two orders of magnitude then remains almost constant until the end of the flare when it apparently increases again

    Learners reconceptualising education: Widening participation through creative engagement?

    No full text
    This paper argues that engaging imaginatively with ways in which statutory and further education is provided and expanding the repertoire of possible transitions into higher education, is necessary for providers both in higher education and in the contexts and phases which precede study at this level. Fostering dispositions for creativity in dynamic engagement with educational technology together with the consideration of pedagogy, learning objects, inclusion, policy and the management of change, requires innovative provision to span the spaces between school, home, work and higher education learning. Reporting on The Aspire Pilot, a NESTA-funded initiative at The Open University, the paper offers the beginning of a theoretical frame for considering learning, learners and learning systems in the information age prioritizing learner agency. It will report emergent empirical findings from this inter-disciplinary project, with a significant e-dimension, which seeks to foster the creativity of 13-19 year olds in considering future learning systems, developing provocations for others to explore creative but grounded possibilities. It explores implications arising from this project for approaches that may facilitate widening participation in higher education

    Near-threshold high-order harmonic spectroscopy with aligned molecules

    Full text link
    We study high-order harmonic generation in aligned molecules close to the ionization threshold. Two distinct contributions to the harmonic signal are observed, which show very different responses to molecular alignment and ellipticity of the driving field. We perform a classical electron trajectory analysis, taking into account the significant influence of the Coulomb potential on the strong-field-driven electron dynamics. The two contributions are related to primary ionization and excitation processes, offering a deeper understanding of the origin of high harmonics near the ionization threshold. This work shows that high harmonic spectroscopy can be extended to the near-threshold spectral range, which is in general spectroscopically rich.Comment: 4 pages, 4 figure

    Jamming in complex networks with degree correlation

    Full text link
    We study the effects of the degree-degree correlations on the pressure congestion J when we apply a dynamical process on scale free complex networks using the gradient network approach. We find that the pressure congestion for disassortative (assortative) networks is lower (bigger) than the one for uncorrelated networks which allow us to affirm that disassortative networks enhance transport through them. This result agree with the fact that many real world transportation networks naturally evolve to this kind of correlation. We explain our results showing that for the disassortative case the clusters in the gradient network turn out to be as much elongated as possible, reducing the pressure congestion J and observing the opposite behavior for the assortative case. Finally we apply our model to real world networks, and the results agree with our theoretical model

    Music and drama in primary schools in the Madeira Island - Narratives of ownership and leadership

    Get PDF
    Este artigo foi uma das publicações resultantes do projeto financiado pela FCT "Música e Drama no 1º ciclo do Ensino básico – o caso da Região Autónoma da Madeira" (PTDC/CED/72112/2006).A three-year-case study funded by the Foundation for Science and Technology (FCT) from the Portuguese Ministry of Science, Technology and Higher Education was designed to study a 30-year project of music and drama in primary schools in Madeira. This article reports on the narratives of the three main figures in the project as they elaborate on its construction according to the following themes: innovation, philosophies of music education and teacher education. Through the lens of a narrative inquiry, the discourses produced are analysed, taking into account the emerging concepts of ownership and leadership.

    Tunable UV Filters

    Get PDF
    This report describes an investigation intended to determine the practical short wavelength limit for Fabry-Perot etalons operating in the far ultraviolet. This portion of the investigation includes a design study of multilayer dielectric reflector coatings that would be required by such an etalon. Results of the study indicate that etalons may be made to operate at wavelengths as short as 121 nm
    corecore