13,943 research outputs found

    Structural design of a vertical antenna boresight 18.3 by 18.3-m planar near-field antenna measurement system

    Get PDF
    A large very precise near-field planar scanner was proposed for NASA Lewis Research Center. This scanner would permit near-field measurements over a horizontal scan plane measuring 18.3 m by 18.3 m. Large aperture antennas mounted with antenna boresight vertical could be tested up to 60 GHz. When such a large near field scanner is used for pattern testing, the antenna or antenna system under test does not have to be moved. Hence, such antennas and antenna systems can be positioned and supported to simulate configuration in zero g. Thus, very large and heavy machinery that would be needed to accurately move the antennas are avoided. A preliminary investigation was undertaken to address the mechanical design of such a challenging near-field antenna scanner. The configuration, structural design and results of a parametric NASTRAN structural optimization analysis are contained. Further, the resulting design was dynamically analyzed in order to provide resonant frequency information to the scanner mechanical drive system designers. If other large near field scanners of comparable dimensions are to be constructed, the information can be used for design optimization of these also

    Infrared-Faint Radio Sources are at high redshifts

    Get PDF
    Context: Infrared-Faint Radio Sources (IFRS) are characterised by relatively high radio flux densities and associated faint or even absent infrared and optical counterparts. The resulting extremely high radio-to-infrared flux density ratios up to several thousands were previously known only for High-redshift Radio Galaxies (HzRGs), suggesting a link between the two classes of object. Prior to this work, no redshift was known for any IFRS in the Australia Telescope Large Area Survey (ATLAS) fields which would help to put IFRS in the context of other classes of object, especially of HzRGs. Aims: This work aims at measuring the first redshifts of IFRS in the ATLAS fields. Further, we test the hypothesis that IFRS are similar to HzRGs, as higher-redshift or dust-obscured versions of these massive galaxies. Methods: A sample of IFRS was spectroscopically observed using the Focal Reducer and Low Dispersion Spectrograph 2 (FORS2) at the Very Large Telescope (VLT). The data were calibrated based on the Image Reduction and Analysis Facility (IRAF) and redshifts extracted. This information was then used to calculate rest-frame luminosities, and to perform the first spectral energy distribution modelling of IFRS based on redshifts. Results: We found redshifts of 1.84, 2.13, and 2.76, for three IFRS, confirming the suggested high-redshift character of this class of object. These redshifts as well as the resulting luminosities show IFRS to be similar to HzRGs. We found further evidence that fainter IFRS are at even higher redshifts. Conclusions: Considering the similarities between IFRS and HzRGs substantiated in this work, the detection of IFRS, which have a significantly higher sky density than HzRGs, increases the number of Active Galactic Nuclei in the early universe and adds to the problems of explaining the formation of supermassive black holes shortly after the Big Bang.Comment: 7 pages, 4 figures; version in prin

    PC3 Breast and Prostate Cancer Productivity Costs: A Comparison of the Human Capital Approach and Friction Cost Approach

    Get PDF
    AbstractObjectivesProductivity costs constitute a substantial proportion of the total societal costs associated with cancer. We compared the results of applying two different analytical methods—the traditional human capital approach (HCA) and the emerging friction cost approach (FCA)—to estimate breast and prostate cancer productivity costs in Ireland in 2008.MethodsData from a survey of breast and prostate cancer patients were combined with population-level survival estimates and a national wage data set to calculate costs of temporary disability (cancer-related work absence), permanent disability (workforce departure, reduced working hours), and premature mortality.ResultsFor breast cancer, productivity costs per person using the HCA were €193,425 and those per person using the FCA were €8,103; for prostate cancer, the comparable estimates were €109,154 and €8,205, respectively. The HCA generated higher costs for younger patients (breast cancer) because of greater lifetime earning potential. In contrast, the FCA resulted in higher productivity costs for older male patients (prostate cancer) commensurate with higher earning capacity over a shorter time period. Reduced working hours postcancer was a key driver of total HCA productivity costs. HCA costs were sensitive to assumptions about discount and growth rates. FCA costs were sensitive to assumptions about the friction period.ConclusionsThe magnitude of the estimates obtained in this study illustrates the importance of including productivity costs when considering the economic impact of illness. Vastly different results emerge from the application of the HCA and the FCA, and this finding emphasizes the importance of choosing the study perspective carefully and being explicit about assumptions that underpin the methods

    Effect of Increasing Levels of Condensed Corn Distillers Solubles on Performance of Finishing Steers

    Get PDF
    A trial was conducted as a randomized block design to assess the effects of condensed corn distillers solubles (CCDS) on performance and carcass merit of yearling steers (n = 21 6) fed 90% concentrate finishing diets. CCDS was included at 0 (MSBM), 5 (5CCDS1, 10 (IOCCDS), or 20% (20CCDS) of diet DM, replacing soybean meal, molasses, and corn. Average daily gain increased (PC .051 for steers fed CCDS but, along with a numerical trend (P= .14) of increasing DMI, resulted in no improvement in FIG (P\u3e.20). Steers were harvested on day 108. Carcass weight and dressing percent for steers fed CCDS were greater than control steers (P\u3c .01). Other carcass characteristics did not differ by treatment (P \u3e .20). Ruminal fluid was collected by stomach tube from steers (n = 72) at -.5, + 1, +4, and + 7 hours from feeding. Values reported are means across sampling times. Ruminal fluid pH was higher for CCDS fed cattle than MSBM (P\u3c.05). Butyrate increased with increasing CCDS level (PC .05). Differences in acetate, propionate, and NH3N were not significant (P\u3e .20). The CCDS was an effective protein and energy source in 90% concentrate corn-based finishing diets. Based on performance, maximum inclusion rate is at least 20% of diet DM

    Cancer And Premature Mortality In Ireland: An Employer's Perspective Following The Friction Cost Approach.

    Get PDF
    Cancer is the second leading cause of death in Ireland accounting for approximately 30% of all deaths. Of these, almost a third arise in those of working age. As well as the public health burden, cancer also imposes economic costs on society in general and employers in particular. This study measured the productivity costs associated with cancer-related premature mortality from an employer’s perspective in Ireland
    corecore