5,938 research outputs found

    A Case of Spinal Epidural Lipomatosis Presenting as a Stroke Mimic

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    Spinal Epidural Lipomatosis (SEL) an excess of normal adipose tissue in the epidural space of the spinal canal, typically becoming symptomatic when cord compression results. First described in 1975 by Lee et al (Lee M, 1975), it is a relatively rare disease. Unfortunately, it is often diagnosed once patients have developed marked symptoms and can have dire complications. Oftentimes SEL is completely asymptomatic, and symptoms on initial presentation are vague. Mostly commonly it presents as worsening chronic back pain (Daniel R. Fassett M.D. M.B.A., 2004) with progressive lower extremity weakness and occasional cauda equina syndrome (Wells AJ, 2014), but this is of course dependent on the level of the culprit lesions. What is unique about this case as compared to other instances of SLE, is that it presented as a stroke mimic. Ultimately little is known about the pathogenesis of this disease process, but generally SEL can be attributed to the following: exogenous steroids, excess endogenous steroid production from endocrine abnormalities, obesity, postsurgical changes, and idiopathic disease (Daniel R. Fassett M.D. M.B.A., 2004). With back pain being one of the most commonly encountered chief complaints in the ED, SEL proves itself as an example as to the importance of broad differentials

    EMPLOYING WIKI AS A COLLABORATIVE INFORMATION REPOSITORY IN A MEDIA AND ENTERTAINMENT COMPANY: THE NBC UNIVERSAL CASE

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    Wiki has been widely accepted by educational institutions, homes, and corporations, and is expected to grow continuously. Business enterprises quickly recognize the value of shared content: Some of the largest corporations, such as Google and IBM use wikis to manage daily operations and to share information among employees. This case study presents how NBC Universal developed a wiki, and used it to enhance knowledge-sharing, thereby achieving significant costsavings, performance improvement and employee satisfactions. This case shows Wiki can bring greater value to an organization with a dynamically changing structure in which capturing and sharing of tacit knowledge is critical for its success. By clearly demonstrating benefits of collaborative information repositories in the widely-recognized media and entertainment firm, this case will provide valuable learning opportunities to both professional and academic audience

    OPTIC: Orbiting Plutonian Topographic Image Craft Proposal for an Unmanned Mission to Pluto

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    The proposal for an unmanned probe to Pluto is presented and described. The Orbiting Plutonian Topographic Image Craft's (OPTIC's) trip will take twenty years and after its arrival, will begin its data collection which includes image and radar mapping, surface spectral analysis, and magnetospheric studies. This probe's design was developed based on the request for proposal of an unmanned probe to Pluto requirements. The distinct problems which an orbiter causes for each subsystem of the craft are discussed. The final design revolved around two important factors: (1) the ability to collect and return the maximum quantity of information on the Plutonian system; and (2) the weight limitations which the choice of an orbiting craft implied. The velocity requirements of this type of mission severely limited the weight available for mission execution-owing to the large portion of overall weight required as fuel to fly the craft with present technology. The topics covered include: (1) scientific instrumentation; (2) mission management; (3) power and propulsion; (4) attitude and articulation control; (5) structural subsystems; and (6) command, control, and communication

    The Globular Cluster System of the Coma cD Galaxy NGC 4874 from Hubble Space Telescope ACS and WFC3/IR Imaging

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    We present new HST optical and near-infrared (NIR) photometry of the rich globular cluster (GC) system of NGC 4874, the cD galaxy in the core of the Coma cluster (Abell 1656). NGC 4874 was observed with the HST Advanced Camera for Surveys in the F475W (g) and F814W (I) passbands and the Wide Field Camera 3 IR Channel in F160W (H). The GCs in this field exhibit a bimodal optical color distribution with more than half of the GCs falling on the red side at g-I > 1. Bimodality is also present, though less conspicuously, in the optical-NIR I-H color. Consistent with past work, we find evidence for nonlinearity in the g-I versus I-H color-color relation. Our results thus underscore the need for understanding the detailed form of the color-metallicity relations in interpreting observational data on GC bimodality. We also find a very strong color-magnitude trend, or "blue tilt," for the blue component of the optical color distribution of the NGC 4874 GC system. A similarly strong trend is present for the overall mean I-H color as a function of magnitude; for M_814 < -10 mag, these trends imply a steep mass-metallicity scaling with ZMGC1.4±0.4Z\propto M_{\rm GC}^{1.4\pm0.4}, but the scaling is not a simple power law and becomes much weaker at lower masses. As in other similar systems, the spatial distribution of the blue GCs is more extended than that of the red GCs, partly because of blue GCs associated with surrounding cluster galaxies. In addition, the center of the GC system is displaced by 4+/-1 kpc towards the southwest from the luminosity center of NGC 4874, in the direction of NGC 4872. Finally, we remark on a dwarf elliptical galaxy with a noticeably asymmetrical GC distribution. Interestingly, this dwarf has a velocity of nearly -3000 km/s with respect to NGC 4874; we suggest it is on its first infall into the cluster core and is undergoing stripping of its GC system by the cluster potential.Comment: 24 pages, 20 figures, accepted for publication in Ap

    Volumetric and Voxel-Wise Analysis of Dominant Intraprostatic Lesions on Multiparametric MRI

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    Introduction: Multiparametric MR imaging (mpMRI) has shown promising results in the diagnosis and localization of prostate cancer. Furthermore, mpMRI may play an important role in identifying the dominant intraprostatic lesion (DIL) for radiotherapy boost. We sought to investigate the level of correlation between dominant tumor foci contoured on various mpMRI sequences. Methods: mpMRI data from 90 patients with MR-guided biopsy-proven prostate cancer were obtained from the SPIE-AAPM-NCI Prostate MR Classification Challenge. Each case consisted of T2-weighted (T2W), apparent diffusion coefficient (ADC), and K(trans) images computed from dynamic contrast-enhanced sequences. All image sets were rigidly co-registered, and the dominant tumor foci were identified and contoured for each MRI sequence. Hausdorff distance (HD), mean distance to agreement (MDA), and Dice and Jaccard coefficients were calculated between the contours for each pair of MRI sequences (i.e., T2 vs. ADC, T2 vs. K(trans), and ADC vs. K(trans)). The voxel wise spearman correlation was also obtained between these image pairs. Results: The DILs were located in the anterior fibromuscular stroma, central zone, peripheral zone, and transition zone in 35.2, 5.6, 32.4, and 25.4% of patients, respectively. Gleason grade groups 1-5 represented 29.6, 40.8, 15.5, and 14.1% of the study population, respectively (with group grades 4 and 5 analyzed together). The mean contour volumes for the T2W images, and the ADC and K(trans) maps were 2.14 +/- 2.1, 2.22 +/- 2.2, and 1.84 +/- 1.5 mL, respectively. K(trans) values were indistinguishable between cancerous regions and the rest of prostatic regions for 19 patients. The Dice coefficient and Jaccard index were 0.74 +/- 0.13, 0.60 +/- 0.15 for T2W-ADC and 0.61 +/- 0.16, 0.46 +/- 0.16 for T2W-K(trans). The voxel-based Spearman correlations were 0.20 +/- 0.20 for T2W-ADC and 0.13 +/- 0.25 for T2W-K(trans). Conclusions: The DIL contoured on T2W images had a high level of agreement with those contoured on ADC maps, but there was little to no quantitative correlation of these results with tumor location and Gleason grade group. Technical hurdles are yet to be solved for precision radiotherapy to target the DILs based on physiological imaging. A Boolean sum volume (BSV) incorporating all available MR sequences may be reasonable in delineating the DIL boost volume

    A long, nontranslatable poly(A) RNA stored in the egg of the sea urchin Strongylocentrotus purpuratus

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    Nontranslatable transcripts containing interspersed repetitive sequence elements constitute a major fraction of the poly(A) RNA stored in the cytoplasm of both the sea urchin egg and the amphibian oocyte. We report the first complete sequence of a representative interspersed maternal RNA transcript, called ISp1. The transcript is about 3.7 kb in length [including poly(A) tail]; and the 5' half consists of a cluster of repetitive sequences, whereas the 3' half is single copy. Other repetitive sequences occur in the 5' and 3' regions flanking the transcription unit. In several cloned alleles, the flanking repetitive and single-copy sequences differ, indicating a high degree of insertional and deletional rearrangement around, as well as within, the transcription unit. No significant open reading frames exist in any region of the ISp1 transcript, nor is it spliced to give rise to translatable mRNA in egg or embryo. A 620-nucleotide repetitive sequence element at the 5' end of the ISp1 transcript is also represented in a large number of other long interspersed maternal poly(A) RNAs. In addition, this sequence appears in a prevalent set of small polyadenylated RNAs about 600-nucleotides in length, which disappear almost completely by the gastrula stage of development. The structural features of the ISp1 RNA uncovered in this work exclude several hypotheses of interspersed maternal poly(A) RNA origin and function

    (±)-9-exo-Amino-5,6,7,8-tetrahydro-5,8-methano-9H-benzocyclohepten-8-ol Hydrochloride

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    This is the published version, also available here: http://www.dx.doi.org/10.1107/S0567740878004458

    Complex Radio Spectral Energy Distributions in Luminous and Ultraluminous Infrared Galaxies

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    We use the Expanded Very Large Array to image radio continuum emission from local luminous and ultraluminous infrared galaxies (LIRGs and ULIRGs) in 1 GHz windows centered at 4.7, 7.2, 29, and 36 GHz. This allows us to probe the integrated radio spectral energy distribution (SED) of the most energetic galaxies in the local universe. The 4-8 GHz flux densities agree well with previous measurements. They yield spectral indices \alpha \approx -0.67 (where F_\nu \propto \nu^\alpha) with \pm 0.15 (1\sigma) scatter, typical of nonthermal (synchrotron) emission from star-forming galaxies. The contrast of our 4-8 GHz data with literature 1.5 and 8.4 GHz flux densities gives further evidence for curvature of the radio SED of U/LIRGs. The SED appears flatter near \sim 1 GHz than near \sim 6 GHz, suggesting significant optical depth effects at the lower frequencies. The high frequency (28-37 GHz) flux densities are low compared to extrapolations from the 4-8 GHz data. We confirm and extend to higher frequency a previously observed deficit of high frequency radio emission for luminous starburst galaxies.Comment: 7 pages, 3 figures, 1 table, accepted for publication in the EVLA Special Issue of ApJ Letter
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