44,628 research outputs found

    Host and Habitat Use by Parasitoids (Hymenoptera: Pteromalidae) of House Fly and Stable Fly (Diptera: Muscidae) Pupae

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    House fly and stable fly pupae were collected during the summer from a dairy farm in northern Illinois. Spalangia nigroaenea accounted for most of the parasitoids recovered from house flies. Spalangia nigra, S. endius, Muscidifurax spp., and S. nigroaenea accounted for most of the parasitoids from stable flies. The majority of flies were house flies late in the summer and stable flies early in the summer. Higher percentages of house flies tended to be in samples containing lower substrate moisture and higher substrate temperature. Parasitism of stable flies started earlier and peaked weeks before that of house flies, with overall parasitism highest from mid-to late-summer. Parasitism of house flies, but not stable flies, differed significantly among habitats, being greater in calf hutches than in edge samples. Hymenopterous parasitoids from house flies tended to include a greater percentage of S. nigroaenea (and a lower percentage of Muscidifurax spp.) in calf hutches versus drainage or edge habitats and in sub- strates consisting of mostly wood shavings versus mostly manure. Within samples, differential parasitism of fly species was not detected for S. nigroaenea, S. endius, or Muscidifurax spp.; but S. nigra preferentially parasitized stable flies

    Turbulence simulation mechanization for Space Shuttle Orbiter dynamics and control studies

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    The current version of the NASA turbulent simulation model in the form of a digital computer program, TBMOD, is described. The logic of the program is discussed and all inputs and outputs are defined. An alternate method of shear simulation suitable for incorporation into the model is presented. The simulation is based on a von Karman spectrum and the assumption of isotropy. The resulting spectral density functions for the shear model are included

    Determination of constant-volume balloon capabilities for aeronautical research

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    The proper application of constant-volume balloons (CVB) for measurement of atmospheric phenomena was determined. And with the proper interpretation of the resulting data. A literature survey covering 176 references is included. the governing equations describing the three-dimensional motion of a CVB immersed in a flow field are developed. The flowfield model is periodic, three-dimensional, and nonhomogeneous, with mean translational motion. The balloon motion and flow field equations are cast into dimensionless form for greater generality, and certain significant dimensionless groups are identified. An alternate treatment of the balloon motion, based on first-order perturbation analysis, is also presented. A description of the digital computer program, BALLOON, used for numerically integrating the governing equations is provided

    Filter cassette for high volume air sampler

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    Filter cassette eliminates or substantially reduces contamination of filter media by extraneous material and facilitates handling

    Development of a mechatronic sorting system for removing contaminants from wool

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    Automated visual inspection (AVI) systems have been extended to many fields, such as agriculture and the food, plastic and textile industries. Generally, most visual systems only inspect product defects, and then analyze and grade them due to the lack of any sorting function. This main reason rests with the difficulty of using the image data in real time. However, it is increasingly important to either sort good products from bad or grade products into separate groups usingAVI systems. This article describes the development of a mechatronic sorting system and its integration with a vision system for automatically removing contaminants from wool in real time. The integration is implemented by a personal computer, which continuously processes live images under the Windows 2000 operating system. The developed real-time sorting approach is also applicable to many other AVI systems

    Beyond Traditional Notions of Transitional Justice: How Trials, Truth Commissions, and Other Tools for Accountability Can and Should Work Together

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    Civil conflicts marked by human rights violations leave devastated communities in their wake. The international community has an interest in assuring that justice is done, an interest which the recent establishment of the International Criminal Court (ICC) confirms. The authors argue the ICC should be augmented by additional mechanisms to bear the burden of doing justice and reconstructing communities after such civil conflicts. This Article explores the potential tensions among such mechanisms, including national human rights trials, truth commissions, and community-based gacaca, and emphasizes the importance of consult-ing victims in resolving these tensions. The authors conclude that the ICC should take the lead in coordinating the different mechanisms discussed in the Article as part of post-conflict reconstruction

    Exponential Smoothing Model Selection for Forecasting

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    Applications of exponential smoothing to forecast time series usually rely on three basic methods: simple exponential smoothing, trend corrected exponential smoothing and a seasonal variation thereof. A common approach to select the method appropriate to a particular time series is based on prediction validation on a withheld part of the sample using criteria such as the mean absolute percentage error. A second approach is to rely on the most appropriate general case of the three methods. For annual series this is trend corrected exponential smoothing: for sub-annual series it is the seasonal adaptation of trend corrected exponential smoothing. The rationale for this approach is that a general method automatically collapses to its nested counterparts when the pertinent conditions pertain in the data. A third approach may be based on an information criterion when maximum likelihood methods are used in conjunction with exponential smoothing to estimate the smoothing parameters. In this paper, such approaches for selecting the appropriate forecasting method are compared in a simulation study. They are also compared on real time series from the M3 forecasting competition. The results indicate that the information criterion approach appears to provide the best basis for an automated approach to method selection, provided that it is based on Akaike's information criterion.Model Selection; Exponential Smoothing; Information Criteria; Prediction; Forecast Validation
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