13,921 research outputs found

    Three-dimensional magnetostatic models of the large-scale corona

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    A special class of magnetostatic equilibria is described, which are mathematically simple and yet sufficiently versatile so as to fit any arbitrary normal magnetic flux prescribed at the photosphere. With these solutions, the corona can be modeled with precisely the same mathematically simple procedure as has previously been done with potential fields. The magnetostatic model predicts, in addition to the coronal magnetic field, the three dimensional coronal density which can be compared with coronagraph observations

    NICMOS Observations of the Pre-Main-Sequence Planetary Debris System HD 98800

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    Spectral energy distributions (SEDs) from 0.4 to 4.7 microns are presented for the two principal stellar components of HD~98800, A and B. The third major component, an extensive planetary debris system (PDS), emits > 20% of the luminosity of star B in a blackbody SED at 164 +/- 5K extending from mid-IR to millimeter-wavelengths. At 0.95 microns a preliminary upper limit of < 0.06 is obtained for the ratio of reflected light to the total from star B. This result limits the albedo of the PDS to < 0.3. Values are presented for the temperature, luminosity, and radius of each major systemic component. Remarkable similarities are found between the PDS and the interplanetary debris system around the Sun as it could have appeared a few million years after its formation.Comment: LaTeX, 9 pages with 1 encapsulated postscript figure and one specially formatted Table which is rendered as a postscript file and included as a figure. Accepted for publication in Astrophysical Journal Letter

    A triclinic polymorph of benzanilide : disordered molecules form hydrogen-bonded chains

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    Peer reviewedPublisher PD

    Effect of forward motion on engine noise

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    Methods used to determine a procedure for correcting static engine data for the effects of forward motion are described. Data were analyzed from airplane flyover and static-engine tests with a JT8D-109 low-bypass-ratio turbofan engine installed on a DC-9-30, with a CF6-6D high-bypass-ratio turbofan engine installed on a DC-10-10, and with a JT9D-59A high-bypass-ratio turbofan engine installed on a DC-10-40. The observed differences between the static and the flyover data bases are discussed in terms of noise generation, convective amplification, atmospheric propagation, and engine installation. The results indicate that each noise source must be adjusted separately for forward-motion and installation effects and then projected to flight conditions as a function of source-path angle, directivity angle, and acoustic range relative to the microphones on the ground

    The Autistic Experience of Exercising within Nature-Based Environments: An Interpretive Phenomenological Analysis

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    Background: The psychological impact of exercising in nature has gained considerable research attention in recent years under the heading green exercise (GE). Literature has examined specific benefits of GE, comparison between indoor and outdoor environments and has utilised different theories to understand these benefits and differences. To date no academic literature has examined the impact of GE on autistic people with a diagnoses of Aspergers Syndrome (AS) (a former term to refer to autism without an accompanying intellectual disability), and a condition characterised by hypersensitive and hyposensitive senses, intuitively it has been suggested that the natural environment might not be a compatible setting for autistic people due to its unpredictable and sensory provoking conditions. Method: A group of four autistic males were interviewed using a semi structured interview schedule. Interviews were transcribed and then analysed using interpretive phenomenological analysis (IPA). Results/Discussion: Three superordinate themes were identified, positive introductions to nature (this group discussed how important having a good start in this environment was to engaging in this activity), positive association with nature (the participants viewed natural environments where they exercised in a positive way), and purpose and practicalities (participants spoke of viewing GE favourably when there was a purpose to it above and beyond doing it for its own sake) with 5 associated subordinate themes. Results suggest that autistic people appear to get considerable positive psychological outcomes from engaging within GE which relate directly to some of the features of AS e.g. disruptive concerns and that a functional purpose to the GE would be helpful in terms of encouraging uptake of and adherence to GE within an autistic group

    Vision screening in children:a retrospective study of social and demographic factors with regard to visual outcomes

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    BACKGROUND: Amblyopia and its risk factors have been demonstrated to be more common among children from low socioeconomic backgrounds. We sought to investigate this association in a region with orthoptic-delivered screening and whole population coverage, and to also examine the association of the Health Plan Indicator (HPI) with screening outcome. METHODS: Screening examination outcomes, postcodes and HPIs were extracted from the community child health database for every child who underwent preschool vision screening between March 2010 and February 2011 Tayside. We obtained the Scottish Index of Multiple Deprivation score for every child as a measure of area-based deprivation. We assessed the vulnerability/needs of the individual family through the HPIā€”ā€˜Coreā€™ (children and families receiving universal health visiting service), ā€˜Additionalā€™ (receiving additional health/social support) and ā€˜Intensiveā€™ (receiving high levels of support). The outcomes from follow-up examinations for those who failed screening were extracted from the orthoptic department database. RESULTS: 4365 children were screened during the year 2010ā€“2011 of whom 523 (11.9%) failed. The odds of children from the least deprived socioeconomic group passing the visual screening test was 1.4 times higher than those from the most deprived socioeconomic group (OR 1.4, 95% CI 1.07 to 1.89, p=0.01). The odds of a child from a family assigned as ā€˜Intensiveā€™ failing the preschool visual screening test was three times greater than the odds of a child from a family assigned as ā€˜Coreā€™ (OR 3.59, 95% CI 1.6 to 7.8, p=0.001). CONCLUSIONS: We found that children from the most deprived backgrounds and those from unstable homes were more likely to fail preschool vision screening
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