170,350 research outputs found
A Report on Literature Search and Archaeological Survey in the Vicinity of Point Comfort, Calhoun County, Texas
No full textDuring May 1979, archaeologists from the Center for Archaeological Research, The University of Texas at San Antonio, conducted literature research and an archaeological field survey of an area to be developed by the Formosa Plastic Company near Point Comfort, Calhoun County, Texas.
The field and literature survey was done under contract between the Center for Archaeological Research (UTSA) and the Pace Company of Houston, Texas. In this report, the results of the field survey are presented by Thomas C. Kelly, Research Associate of the Center; the literature review was prepared by Herbert Uecker, Technical Staff Assistant. All project work was done under the supervision of Dr. Thomas R. Hester, Director of the Center, and Mr. Jack D. Eaton, Assistant Director
Idealisierung falscher Praxis. Vom richtigen Leben im falschen
No full textHeinrich M, Uecker M. Idealisierung falscher Praxis. Vom richtigen Leben im falschen. In: Gruschka A, Pollmanns M, Leser C, eds. Bürgerliche Kälte und Pädagogik. Zur Ontogenese des moralischen Urteils. Opladen ; Berlin: Budrich; 2021: 138-147.[Wiederabdruck von Auszügen aus: Heinrich, M., & Uecker, M. (2000). Vom richtigen Leben im falschen. Idealisierung falscher Praxis als Reaktion auf bürgerliche Kälte. Pädagogische Korrespondenz. Zeitschrift für kritische Zeitdiagnostik in Pädagogik und Gesellschaft, 2000(26), 39-48.
A Multi-GPU Programming Library for Real-Time Applications
No full textWe present MGPU, a C++ programming library targeted at single-node multi-GPU systems. Such systems combine disproportionate floating point performance with high data locality and are thus well suited to implement real-time algorithms. We describe the library design, programming interface and implementation details in light of this specific problem domain. The core concepts of this work are a novel kind of container abstraction and MPI-like communication methods for intra-system communication. We further demonstrate how MGPU is used as a framework for porting existing GPU libraries to multi-device architectures. Putting our library to the test, we accelerate an iterative non-linear image reconstruction algorithm for real-time magnetic resonance imaging using multiple GPUs. We achieve a speed-up of about 1.7 using 2 GPUs and reach a final speed-up of 2.1 with 4 GPUs. These promising results lead us to conclude that multi-GPU systems are a viable solution for real-time MRI reconstruction as well as signal-processing applications in general
A report on literature search and archaeological survey in the vicinity of Point Comfort, Calhoun County, Texas
No full textDuring May 1979, archaeologists from the Center for Archaeological Research, The University of Texas at San Antonio, conducted literature research and an archaeological field survey of an area to be developed by the Formosa Plastic Company near Point Comfort, Calhoun County, Texas. The field and literature survey was done under contract between the Center for Archaeological Research (UTSA) and the Pace Company of Houston, Texas. In this report, the results of the field survey are presented by Thomas C. Kelly, Research Associate of the Center; the literature review was prepared by Herbert Uecker, Technical Staff Assistant. All project work was done under the super-vision of Dr. Thomas R. Hester, Director of the Center, and Mr. Jack D. Eaton, Assistant Director.Formosa Plastic Compan
Inverse reconstruction method for segmented multi-shot diffusion-weighted MRI with multiple coils.
No full textEach k-space segment in multishot diffusion-weighted MRI is affected by a different spatially varying phase which is caused by unavoidable motions and amplified by the diffusion-encoding gradients. A proper image reconstruction therefore requires phase maps for each segment. Such maps are commonly derived from two-dimensional navigators at relatively low resolution but do not offer robust solutions. For example, phase variations in diffusion-weighted MRI of the brain are often characterized by high spatial frequencies. To overcome this problem, an inverse reconstruction method for segmented multishot diffusion-weighted MRI is described that takes advantage of the full k-space data acquired from multiple receiver coils. First, the individual coil sensitivities are determined from the non-diffusion-weighted acquisitions by regularized nonlinear inversion. These coil sensitivities are then used to estimate accurate motion-associated phase maps for each segment by iterative linear inversion. Finally, the coil sensitivities and phase maps serve to reconstruct artifact-free images of the object by iterative linear inversion, taking advantage of the data of all segments. The efficiency of the new method is demonstrated for segmented diffusion-weighted stimulated echo acquisition mode MRI of the human brain. Magn Reson Med 62:1342-1348, 2009. (C) 2009 Wiley-Liss, Inc
Nonlinear inverse reconstruction for real-time MRI of the human heart using undersampled radial FLASH.
No full textA previously proposed nonlinear inverse reconstruction for auto-calibrated parallel imaging simultaneously estimates coil sensitivities and image content. This work exploits this property for real-time MRI, where coil sensitivities need to be dynamically adapted to the conditions generated by moving objects. The development comprises (i) an extension of the nonlinear inverse algorithm to non-Cartesian k-space encodings, (ii) its implementation on a graphical processing unit to reduce reconstruction times, and (iii) the use of a convolution-based iteration, which considerably simplifies the graphical processing unit implementation compared to a gridding technique. The method is validated for real-time MRI of the human heart at 3 T using radio frequency-spoiled radial FLASH (pulse repetition time/echo time = 2.0/1.3 ms, flip angle 8 degrees). The results demonstrate artifact-free reconstructions from only 65-85 spokes, with 256 oversampled data points. Acquisition times of 130-170 ms resulted in 29-38 frames per second for sliding window reconstructions (factor 5). While offline reconstructions required 1-2 sec, real-time applications with modified parameters and slightly lower image quality were achieved within 90 ms per graphical processing unit. Magn Reson Med 63:1456-1462, 2010. (C) 2010 Wiley-Liss, Inc
Going Beyond Counting First Authors in Author Co-citation Analysis
No full textThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Mitomycin C in highly myopic eyes - Author reply
No full textOphthalmology. 2005 Feb;112(2):208-18; discussion 219.
Mitomycin C modulation of corneal wound healing after photorefractive keratectomy in highly myopic eyes.
Gambato C, Ghirlando A, Moretto E, Busato F, Midena E.
SourceRefractive Surgery Service and Antimetabolite Therapy Research Unit, Department of Ophthalmology, University of Padova, Padova, Italy.
Abstract
PURPOSE: To evaluate the role of topical mitomycin C in corneal wound healing (CWH) after photorefractive keratectomy (PRK) in highly myopic eyes.
DESIGN: Prospective, double-masked, randomized clinical trial.
PARTICIPANTS: Seventy-two eyes of 36 patients affected by high (>7 diopters) myopia.
METHODS: In each patient, one eye was randomly assigned to PRK with intraoperative topical 0.02% mitomycin C application, and the fellow eye was treated with a placebo. Postoperatively, mitomycin C-treated eyes received artificial tears (3 times daily, tapered in 3 months), whereas the fellow eye was treated with fluorometholone sodium 2% and artificial tears (3 times daily, tapered in 3 months).
MAIN OUTCOME MEASURES: Uncorrected visual acuity (UCVA) and best-corrected visual acuity (BCVA), contrast sensitivity, manifest refraction, and biomicroscopy. Contrast sensitivity was determined using the Pelli-Robson chart. Corneal confocal microscopy documented CWH.
RESULTS: Mean follow-up was 18 months (range, 12-36). No side effects or toxic effects were documented. At 12-month follow-up examination, UCVAs (logarithm of the minimum angle of resolution) were 0.4+/-0.48 and 0.5+/-0.53 (P = .03) in mitomycin C-treated eyes and corticosteroid-treated eyes, respectively. At 1 year, corneal haze developed in 20% of corticosteroid-treated eyes, versus 0% of mitomycin C-treated eyes. At 12, 24, and 36 months, corneal confocal microscopy showed activated keratocytes and extracellular matrix significantly more evident in untreated eyes (Ps = 0.004, 0.024, and 0.046, respectively).
CONCLUSION: Topical intraoperative application of 0.02% mitomycin C can reduce haze formation in highly myopic eyes undergoing PRK.
Comment in
Ophthalmology. 2006 Feb;113(2):357; author reply 357-8
Dispelling the Myths Behind First-author Citation Counts
No full textWe conducted a full-scale evaluative citation analysis study of scholars in the XML research field to explore just how different from each other author rankings resulting from different citation counting methods actually are, and to demonstrate the capability of emerging data and tools on the Web in supporting more realistic citation counting methods. Our results contest some common arguments for the continued
use of first-author citation counts in the evaluation of scholars, such as high correlations between author rankings by first-author citation counts and other citation
counting methods, and high costs of using more realistic citation counting methods that are not well-supported by the ISI databases. It is argued that increasingly available digital full text research papers make it possible for citation analysis studies to go beyond what the ISI databases have directly supported and to employ more
sophisticated methods
Parallel imaging with nonlinear reconstruction using variational penalties.
No full textA new approach based on nonlinear inversion for autocalibrated parallel imaging with arbitrary sampling patterns is presented. By extending the iteratively regularized GaussNewton method with variational penalties, the improved reconstruction quality obtained from joint estimation of image and coil sensitivities is combined with the superior noise suppression of total variation and total generalized variation regularization. In addition, the proposed approach can lead to enhanced removal of sampling artifacts arising from pseudorandom and radial sampling patterns. This is demonstrated for phantom and in vivo measurements. Magn Reson Med 67:3441, 2012. (C) 2011 Wiley Periodicals, Inc
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