1,232 research outputs found

    Calculations of laser cavity dumping for optical communications

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    For deep-space pulse-position modulation (PPM) optical communication links using Nd:YAG lasers, two types of laser transmitter modulation techniques are available for efficiently producing laser pulses over a broad range of repetition rates: Q-switching and cavity dumping. The desired modulation scheme is dependent on the required pulse repetition frequency and link parameters. These two techniques are discussed, theoretical and numerical calculations of the internal energy of the laser cavity in cavity dumping are described, and an example of cavity dumping is applied to a link for a proposed experiment package on Cassini

    AMCIS 2010 Panel Report: External Benchmarks in Information Systems Program Assessment

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    Accrediting bodies and other external constituencies are placing increased emphasis on the assessment of academic degree programs for continuous improvement. Most assessment plans are focused on determining how well program outcomes or goals are being met. However, benchmarking a degree program across institutions is rarely considered. This article provides general principles for assessing information systems programs and presents quantitative and qualitative methodologies and tools for benchmarking student learning in Information Systems programs

    Serum selenium concentrations and diabetes in U.S. adults : National Health and Nutrition Examination Survey (NHANES) 2003ā€“2004

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    Background: Increasing evidence suggests that high selenium levels are associated with diabetes and other cardiometabolic risk factors. Objectives: We evaluated the association of serum selenium concentrations with fasting plasma glucose, glycosylated hemoglobin levels, and diabetes in the most recently available representative sample of the U.S. population. Methods: We used a cross-sectional analysis of 917 adults ā‰„ 40 years of age who had a fasting morning blood sample in the National Health and Nutrition Examination Survey 2003ā€“2004. We evaluated the association of serum selenium, measured by inductively coupled plasma-dynamic reaction cell-mass spectrometry, and diabetes, defined as a self-report of current use of hypoglycemic agents or insulin or as fasting plasma glucose ā‰„ 126 mg/dL. Results: Mean serum selenium was 137.1 Ī¼g/L. The multivariable adjusted odds ratio [95% confidence interval (CI)] for diabetes comparing the highest quartile of serum selenium (ā‰„ 147 Ī¼g/L) with the lowest (< 124 Ī¼g/L) was 7.64 (3.34ā€“17.46). The corresponding average differences (95% CI) in fasting plasma glucose and glycosylated hemoglobin were 9.5 mg/dL (3.4ā€“15.6 mg/dL) and 0.30% (0.14ā€“0.46%), respectively. In spline regression models, the prevalence of diabetes as well as glucose and glycosylated hemoglobin levels increased with increasing selenium concentrations up to 160 Ī¼g/L. Conclusions: In U.S. adults, high serum selenium concentrations were associated with higher prevalence of diabetes and higher fasting plasma glucose and glycosylated hemoglobin levels. Given high selenium intake in the U.S. population, further research is needed to determine the role of excess selenium levels in the development or the progression of diabetes
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