2,935 research outputs found
The repeatability of self-reported exposure after miscarriage
BACKGROUND: The Avon Longitudinal Study of Pregnancy and Childhood is a prospective study of women who were resident in Avon and who were expected to deliver a baby between April 1991 and December 1992. METHODS: The study provided an opportunity to test the repeatability of responses from 220 women who experienced a miscarriage and who reported exposure to occupational substances and common household products and appliances in two questionnaires. The first questionnaire was completed in the early part of the pregnancy and the second after the miscarriage. Women were asked to score their frequency of exposure on a five-point scale from 'daily' to 'never'. Their responses were analysed to assess the degree of agreement between replies to identical questions in the two questionnaires using the kappa statistic. A new frequency variable was created which compared the replies for the two questionnaires; this was analysed for all exposures by cross-tabulation with possible explanatory variables (age of mother, social class, history of miscarriage and the time lag between questionnaires). RESULTS: In general there was good agreement in the reported exposures to 48 substances and products. The results showed a small and consistent pattern of reporting exposures less frequently in the second questionnaire, i.e. after miscarriage. This was not explained by the analysis of possible confounding variables. Given the literature, the authors had expected to find a shift in the opposite direction. CONCLUSION: The study reinforces the need to be cautious when using the results from single surveys of retrospective self-reported exposure
Electron paramagnetic resonance studies of ferric ions in myoglobin
This thesis reports investigations of the protein molecule myoglobin by means of electron paramagnetic resonance and supplemented by optical absorption measurements.
Certain ions can be attached to the sixth coordination point of the iron atom in the haem site of the myoglobin molecule. Attachment of these ions causes the iron ion to be in either the ferric or ferrous state. Several ferric types (or derivatives) of myoglobin are studied at microwave frequencies of 35 GHz and 70 GHz
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OER Evidence Report 2013-2014
The Open Educational Resources Research Hub (OER Research Hub) provides a focus for research, designed to give answers to the overall question ‘What is the impact of OER on learning and teaching practices?’ and identify the particular influence of openness. We do this by working in collaboration with projects across four education sectors (K12, college, higher education and informal) extending a network of research with shared
methods and shared results.
The project combines:
– Targeted research collaboration with high profile OER projects
– A programme of international fellowship
– Global networking and expertise in OER implementation and evaluation
– A hub for research data and excellence in practice
This report is an interim review of evidence recorded against the key hypotheses that focus the research of the
OER Research Hub project
Transparent and Flexible Thin Film Electroluminescent Devices Using HiTUS Deposition and Laser Processing Fabrication
Highly transparent thin film electroluminescent structures offering excellent switch on characteristics, high luminance and large break-down voltages have been deposited onto glass and flexible polymeric materials with no substrate heating using high target utilization sputtering. Deposition of ZnS:Mn as the active light emitting layer and Y2O3,Al2O3,Ta2O5, and HfO2 as dielectric materials arranged in single and multiple layer configurations were investigated. Devices incorporating Al2O3,HfO2 quadruple layers demonstrate the highest attainable luminance at low threshold voltage. Single pulse excimer laser irradiation of the phosphor layer prior to deposition of the top dielectric layer enhanced the luminance of the devices. The devices fabricated on glass and polymeric substrates exhibited a maximum luminance of 500 and 450 cdm−2 when driven at 270 VRMS and 220 VRMS, respectively, with a 1.0 kHz sine wave
What is a better impact message of bean research in Africa: farm productivity or land conservation?
Discussion of bean research to promote both increased productivity and land conservation in Africa
Theoretical modeling of two-color coherent anti-Stokes Raman spectroscopy spectra measured with a frequency-doubled, multimode pump laser
We have theoretically modeled coherent anti-Stokes Raman spectroscopy spectra of nitrogen measured with a frequency-doubled Nd:YAG pump laser. The fluctuations of the multimode pump field are modeled using a field variable having non-Gaussian statistics derived from a functional dependence on a Gaussian field. Both isolated and multiple, overlapping transitions are treated. The model qualitatively predicts the non-Gaussian effects observed in experiments but somewhat overemphasizes the magnitude of these features
Magnetic Properties of Epitaxial and Polycrystalline Fe/Si Multilayers
Fe/Si multilayers with antiferromagnetic interlayer coupling have been grown
via ion-beam sputtering on both glass and single-crystal substrates. High-angle
x-ray diffraction measurements show that both sets of films have narrow Fe
peaks, implying a large crystallite size and crystalline iron silicide spacer
layers. Low-angle x-ray diffraction measurements show that films grown on glass
have rougher interfaces than those grown on single-crystal substrates. The
multilayers grown on glass have a larger remanent magnetization than the
multilayers grown on single-crystal substrates. The observation of
magnetocrystalline anisotropy in hysteresis loops and peaks in x-ray
diffraction demonstrates that the films grown on MgO and Ge are epitaxial. The
smaller remanent magnetization in Fe/Si multilayers with better layering
suggests that the remanence is not an intrinsic property.Comment: 9 pages, RevTex, 4 figures available by fax. Send email to
[email protected] for more info. Submitted to '95 MMM proceeding
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