9,546 research outputs found
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Greater Austin Software Industry Report 1993
Report benchmarking the demographics, infrastructure, business and technology characteristics of Austin area software development firms in 1993. Includes a timeline of Austin's development as a technology center and a directory of 359 software firms in the region.IC2 Institut
Vertebra Shape Classification using MLP for Content-Based Image Retrieval
A desirable content-based image retrieval (CBIR) system would classify extracted image features to support some form of semantic retrieval. The Lister Hill National Center for Biomedical Communications, an intramural R&D division of the National Library for Medicine (NLM), maintains an archive of digitized X-rays of the cervical and lumbar spine taken as part of the second national health and nutrition examination survey (NHANES II). It is our goal to provide shape-based access to digitized X-rays including retrieval on automatically detected and classified pathology, e.g., anterior osteophytes. This is done using radius of curvature analysis along the anterior portion, and morphological analysis for quantifying protrusion regions along the vertebra boundary. Experimental results are presented for the classification of 704 cervical spine vertebrae by evaluating the features using a multi-layer perceptron (MLP) based approach. In this paper, we describe the design and current status of the content-based image retrieval (CBIR) system and the role of neural networks in the design of an effective multimedia information retrieval system
Live Wire Segmentation Tool for Osteophyte Detection in Lumbar Spine X-Ray Images
Computer-assisted vertebra segmentation in x-ray images is a challenging problem. Inter-subject variability and the generally poor contrast of digitized radiograph images contribute to the segmentation difficulty. In this paper, a semi-automated live wire approach is investigated for vertebrae segmentation. The live wire approach integrates initially selected user points with dynamic programming to generate a closed vertebra boundary. In order to assess the degree to which vertebra features are conserved using the live wire technique, convex hull-based features to characterize anterior osteophytes in lumbar vertebrae are determined for live wire and manually segmented vertebrae. Anterior osteophyte discrimination was performed over 405 lumbar vertebrae, 204 abnormal vertebrae with anterior osteophytes and 201 normal vertebrae. A leave-one-out standard back propagation neural network was used for vertebrae segmentation. Experimental results show that manual segmentation yielded slightly better discrimination results than the live wire technique
Image Analysis Techniques for the Automated Evaluation of Subaxial Subluxation in Cervical Spine X-Ray Images
Rheumatoid arthritis is a chronic inflammatory disease affecting synovial joints of the body, especially the hands and feet, spine, knees and hips. For many patients, the cervical spine is associated with rheumatoid arthritis. Subluxation is the abnormal movement of one of the bones that comprise a joint. In this research, image analysis techniques have been investigated for the recognition of cervical spine x-ray images with one or more instances of subaxial subluxation. Receiver operating characteristic curve results are presented, showing potential for subaxial subluxation discrimination on an image-by-image basis
Pennsylvania Folklife Vol. 13, No. 1
• The Paint-Decorated Furniture of the Pennsylvania Dutch • My Mother\u27s Kitchen • H is for Hinkle • An Album of Chester County Farmhouses • Smokehouses in the Lebanon Valley • Morning Glory Cake • Five Years of Folk Festivalinghttps://digitalcommons.ursinus.edu/pafolklifemag/1013/thumbnail.jp
Causes and consequences of flat-slab subduction in southern Peru
Flat or near-horizontal subduction of oceanic lithosphere has been an important tectonic process both currently and in the geologic past. Subduction of the aseismic Nazca Ridge beneath South America has been associated with the onset of flat subduction and the termination of arc volcanism in Peru, making it an ideal place to study flat-slab subduction. Recently acquired seismic recordings for 144 broadband seismic stations in Peru permit us to image the Mohorovičić discontinuity (Moho) of the subducted oceanic Nazca plate, Nazca Ridge, and the overlying continental Moho of the South American crust in detail through the calculation of receiver functions. We find that the subducted over-thickened ridge crust is likely significantly eclogitized ∼350 km from the trench, requiring that the inboard continuation of the flat slab be supported by mechanisms other than low-density crustal material. This continuation coincides with a low-velocity anomaly identified in prior tomography studies of the region immediately below the flat slab, and this anomaly may provide some support for the flat slab. The subduction of the Nazca Ridge has displaced most, if not the entire South American lithospheric mantle beneath the high Andes as well as up to 10 km of the lowermost continental crust. The lack of deep upper-plate seismicity suggests that the Andean crust has remained warm during flat subduction and is deforming ductilely around the subducted ridge. This deformation shows significant coupling between the subducting Nazca oceanic plate and overriding South American continental plate up to ∼500 km from the trench. These results provide important modern constraints for interpreting the geological consequences of past and present flat-slab subduction locations globally
Seismicity and state of stress in the central and southern Peruvian flat slab
We have determined the Wadati–Benioff Zone seismicity and state of stress of the subducting Nazca slab beneath central and southern Peru using data from three recently deployed local seismic networks. Our relocated hypocenters are consistent with a flat slab geometry that is shallowest near the Nazca Ridge, and changes from steep to normal without tearing to the south. These locations also indicate numerous abrupt along-strike changes in seismicity, most notably an absence of seismicity along the projected location of subducting Nazca Ridge. This stands in stark contrast to the very high seismicity observed along the Juan Fernandez ridge beneath central Chile where, a similar flat slab geometry is observed. We interpret this as indicative of an absence of water in the mantle beneath the overthickened crust of the Nazca Ridge. This may provide important new constraints on the conditions required to produce intermediate depth seismicity. Our focal mechanisms and stress tensor inversions indicate dominantly down-dip extension, consistent with slab pull, with minor variations that are likely due to the variable slab geometry and stress from adjacent regions. We observe significantly greater variability in the P-axis orientations and maximum compressive stress directions. The along strike change in the orientation of maximum compressive stress is likely related to slab bending and unbending south of the Nazca Ridge
Overriding plate, mantle wedge, slab, and subslab contributions to seismic anisotropy beneath the northern Central Andean Plateau
The Central Andean Plateau, the second-highest plateau on Earth, overlies the subduction of the Nazca Plate beneath the central portion of South America. The origin of the high topography remains poorly understood, and this puzzle is intimately tied to unanswered questions about processes in the upper mantle, including possible removal of the overriding plate lithosphere and interaction with the flow field that results from the driving forces associated with subduction. Observations of seismic anisotropy can provide important constraints on mantle flow geometry in subduction systems. The interpretation of seismic anisotropy measurements in subduction settings can be challenging, however, because different parts of the subduction system may contribute, including the overriding plate, the mantle wedge above the slab, the slab itself, and the deep upper mantle beneath the slab. Here we present measurements of shear wave splitting for core phases (SKS, SKKS, PKS, and sSKS), local S, and source-side teleseismic S phases that sample the upper mantle beneath southern Peru and northern Bolivia, relying mostly on data from the CAUGHT experiment. We find evidence for seismic anisotropy within most portions of the subduction system, although the overriding plate itself likely makes only a small contribution to the observed delay times. Average fast orientations generally trend roughly trench-parallel to trench-oblique, contradicting predictions from the simplest two-dimensional flow models and olivine fabric scenarios. Our measurements suggest complex, layered anisotropy beneath the northern portion of the Central Andean Plateau, with significant departures from a two-dimensional mantle flow regime
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Summer 1970
The U.S. Nitrogen Industry by George C. Sweeney, Jr. (page 3) Learn the Oil Alphabet by Melvin E. Long (7) Weed Control with Repeated Applications of Tordon Herbicides by John W. Gibson (9) Plants Speed Formation of Soil by Brij L. Sawney (12) St. Augustine Decline (SAD) A Virus Disease of St. Augustine Grass by Norman L. McCoy, Robert W. Toler, and Jose Amador (15) The Problem of Responsibility for Recreation by Ronald F. Paige (19) Editorial (20) Massachusetts Fine Turf Conference (23) Dickinson Memorial Fund (23
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