9,503 research outputs found

    The effects of soil moisture, soil texture, and host orientation on the ability of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) to infect Galleria mellonella (Lepidoptera: Pyralidae)

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    Abstract Entomopathogenic nematodes (EPN) demonstrate potential as a biological control for soil dwelling insects. However, edaphic factors, such as soil moisture and texture impact the efficacy of EPN on a host. The objectives were to examine the effects of soil texture and moisture on 1) the infection rate of Galleria mellonella L. by EPN and; 2) the ability of H. bacteriophora (Poinar) to move through the soil to find a host at different orientations. Soil textures consisted of sand, a sand/silt/peat mixture, and a silt/peat mixture at 50% and 100% moisture. A general linear model was used to evaluate infection rates and EPN movement. Both soil moisture (p \u3c 0.05) and texture (p \u3c 0.05) had significant effects on nematodes infection rates of G. mellonella. Texture, moisture, and host orientation did not significantly affect (p \u3e 0.05) the ability of EPN to find a host. While EPN were able to find a host within a variety of soil types, soils that held more water had higher infection rates than soils that held less water, suggesting that moisture may be a key component in facilitating infection by EPN. By understanding the factors that influence the ability of EPN to find and infect a host, improved bio-control programs using EPN can be developed

    Program for transfer research and impact studies

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    Research activities conducted under the program for Transfer Research and impact studies are reviewed. Programs include: Tech Brief - Technical Support Package (TSP) Program; transfer documentation; and technology transfer profiles. An analysis of user behavior patterns is made by studying questionnaires filled out by users of the Tech Brief - TSP program. The process of technology transfer is discussed in terms of improving its effectiveness

    Deep space network support of the manned space flight network for Apollo, volume 2 Technical memorandum, 1969 - 1970

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    Deep Space Network support activities for Apollo 9 through 13 flights and associated equipmen

    Thermodynamics of beta-amyloid fibril formation

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    Amyloid fibers are aggregates of proteins. They are built out of a peptide called β\beta--amyloid (Aβ\beta) containing between 41 and 43 residues, produced by the action of an enzyme which cleaves a much larger protein known as the Amyloid Precursor Protein (APP). X-ray diffraction experiments have shown that these fibrils are rich in β\beta--structures, whereas the shape of the peptide displays an α\alpha--helix structure within the APP in its biologically active conformation. A realistic model of fibril formation is developed based on the seventeen residues Aβ\beta12--28 amyloid peptide, which has been shown to form fibrils structurally similar to those of the whole Aβ\beta peptide. With the help of physical arguments and in keeping with experimental findings, the Aβ\beta12--28 monomer is assumed to be in four possible states (i.e., native helix conformation, β\beta--hairpin, globular low--energy state and unfolded state). Making use of these monomeric states, oligomers (dimers, tertramers and octamers) were constructed. With the help of short, detailed Molecular Dynamics (MD) calculations of the three monomers and of a variety of oligomers, energies for these structures were obtained. Making use of these results within the framework of a simple yet realistic model to describe the entropic terms associated with the variety of amyloid conformations, a phase diagram can be calculated of the whole many--body system, leading to a thermodynamical picture in overall agreement with the experimental findings. In particular, the existence of micellar metastable states seem to be a key issue to determine the thermodynamical properties of the system

    Autocalibration with the Minimum Number of Cameras with Known Pixel Shape

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    In 3D reconstruction, the recovery of the calibration parameters of the cameras is paramount since it provides metric information about the observed scene, e.g., measures of angles and ratios of distances. Autocalibration enables the estimation of the camera parameters without using a calibration device, but by enforcing simple constraints on the camera parameters. In the absence of information about the internal camera parameters such as the focal length and the principal point, the knowledge of the camera pixel shape is usually the only available constraint. Given a projective reconstruction of a rigid scene, we address the problem of the autocalibration of a minimal set of cameras with known pixel shape and otherwise arbitrarily varying intrinsic and extrinsic parameters. We propose an algorithm that only requires 5 cameras (the theoretical minimum), thus halving the number of cameras required by previous algorithms based on the same constraint. To this purpose, we introduce as our basic geometric tool the six-line conic variety (SLCV), consisting in the set of planes intersecting six given lines of 3D space in points of a conic. We show that the set of solutions of the Euclidean upgrading problem for three cameras with known pixel shape can be parameterized in a computationally efficient way. This parameterization is then used to solve autocalibration from five or more cameras, reducing the three-dimensional search space to a two-dimensional one. We provide experiments with real images showing the good performance of the technique.Comment: 19 pages, 14 figures, 7 tables, J. Math. Imaging Vi

    The effects of soil moisture, soil texture, and host orientation on the ability of Heterorhabditis bacteriophora (Rhabditida: Heterorhabditidae) to infect Galleria mellonella (Lepidoptera: Pyralidae)

    Get PDF
    Abstract Entomopathogenic nematodes (EPN) demonstrate potential as a biological control for soil dwelling insects. However, edaphic factors, such as soil moisture and texture impact the efficacy of EPN on a host. The objectives were to examine the effects of soil texture and moisture on 1) the infection rate of Galleria mellonella L. by EPN and; 2) the ability of H. bacteriophora (Poinar) to move through the soil to find a host at different orientations. Soil textures consisted of sand, a sand/silt/peat mixture, and a silt/peat mixture at 50% and 100% moisture. A general linear model was used to evaluate infection rates and EPN movement. Both soil moisture (p \u3c 0.05) and texture (p \u3c 0.05) had significant effects on nematodes infection rates of G. mellonella. Texture, moisture, and host orientation did not significantly affect (p \u3e 0.05) the ability of EPN to find a host. While EPN were able to find a host within a variety of soil types, soils that held more water had higher infection rates than soils that held less water, suggesting that moisture may be a key component in facilitating infection by EPN. By understanding the factors that influence the ability of EPN to find and infect a host, improved bio-control programs using EPN can be developed

    Hybrid Focal Stereo Networks for Pattern Analysis in Homogeneous Scenes

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    In this paper we address the problem of multiple camera calibration in the presence of a homogeneous scene, and without the possibility of employing calibration object based methods. The proposed solution exploits salient features present in a larger field of view, but instead of employing active vision we replace the cameras with stereo rigs featuring a long focal analysis camera, as well as a short focal registration camera. Thus, we are able to propose an accurate solution which does not require intrinsic variation models as in the case of zooming cameras. Moreover, the availability of the two views simultaneously in each rig allows for pose re-estimation between rigs as often as necessary. The algorithm has been successfully validated in an indoor setting, as well as on a difficult scene featuring a highly dense pilgrim crowd in Makkah.Comment: 13 pages, 6 figures, submitted to Machine Vision and Application

    Self-Calibration of Cameras with Euclidean Image Plane in Case of Two Views and Known Relative Rotation Angle

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    The internal calibration of a pinhole camera is given by five parameters that are combined into an upper-triangular 3×33\times 3 calibration matrix. If the skew parameter is zero and the aspect ratio is equal to one, then the camera is said to have Euclidean image plane. In this paper, we propose a non-iterative self-calibration algorithm for a camera with Euclidean image plane in case the remaining three internal parameters --- the focal length and the principal point coordinates --- are fixed but unknown. The algorithm requires a set of N7N \geq 7 point correspondences in two views and also the measured relative rotation angle between the views. We show that the problem generically has six solutions (including complex ones). The algorithm has been implemented and tested both on synthetic data and on publicly available real dataset. The experiments demonstrate that the method is correct, numerically stable and robust.Comment: 13 pages, 7 eps-figure

    Advancing models of best practice in academic governance and management in higher education institutions in Kazakhstan

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    This is a collaborative research project of Nazarbayev University Graduate School of Education (NUGSE) in partnership with the Graduate School of Education of University of Pennsylvania (PennGSE). The Project aims at studying how academic leaders at public and private institutions in Kazakhstan are preparing for greater institutional autonomy and encouraging innovation [1]

    Program for transfer research and impact studies

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    Research activities conducted under the Program for Transfer Research and Impact Studies (TRIS) during 1972 included: (1) preparation of 10,196 TSP requests for TRIS application analysis; (2) interviews with over 500 individuals concerning the technical, economic, and social impacts of NASA-generated technology; (3) preparation of 38 new technology transfer example files and 101 new transfer cases; and (4) maintenance of a technology transfer library containing more than 2,900 titles. Six different modes of technology utilization are used to illustrate the pervasiveness of the transfer and diffusion of aerospace innovations. These modes also provide a basis for distinguishing the unique characteristics of the NASA Technology Utilization Program. An examination is reported of the ways in which NASA-generated technology is contributing to beneficial social change in five major areas of human concern: health, environment, safety, transportation, and communication
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