68 research outputs found

    CASAD -- Computer-Aided Sonography of Abdominal Diseases - the concept of joint technique impact

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    Ultrasound image is the primary (input) information for every ultrasonic examination. Since being used in ultrasound images analysis the both knowledge-base decision support and content-based image retrieval techniques have their own restrictions, the combination of these techniques looks promissory for covering the restrictions of one by advances of another. In this work we have focused on implementation of the proposed combination in the frame of CASAD (Computer-Aided Sonography of Abdominal Diseases) system for supplying the ultrasound examiner with a diagnostic-assistant tool based on a data warehouse of standard referenced images. This warehouse serves: to manifest the diagnosis when the ecographist specifies the pathology and then looks through corresponding images to verify his opinion; to suggest a second opinion by automatic analysis of the annotation of relevant images that were assessed from the repository using content-based image retrieval

    Preoperative method of assessment of gallbladder lesion in acute cholecystitis

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    Background. To date acute cholecystitis remains one of the most common urgent abdominal diseases in which postoperative complications and mortality are possible.The aim. To assess the correlation of gamma-glutamyltranspeptidase and alkaline phosphatase concentrations in blood plasma with the form of acute cholecystitis.Methods. A study of 105 patients with acute calculous cholecystitis, 35 – with chronic calculous cholecystitis (comparison group), who underwent laparoscopic cholecystectomy, was performed. At admission to the hospital, the activity of gammaglutamyltranspeptidase (GGTP) and alkaline phosphatase in blood plasma was determined by kinetic colorimetric method.Results. A direct correlation was revealed between the level of GGTP concentration and the severity of destruction in the gallbladder wall. With catarrhal cholecystitis, it was 340 ± 116.9 U/l (p < 0.05), with phlegmonous – 108.1 ± 29.5 U/l (p < 0.05), with gangrenous – 32.9 ± 7.5 U/l (p < 0.05). Along with this, a direct correlation was revealed between the concentration of alkaline phosphatase and the severity of destruction in the gallbladder wall. In catarrhal cholecystitis, the enzyme activity was 160.3 ± 34.2 U/l (p < 0.05), in phlegmonous – 129.9 ± 14.6 U/l (p < 0.05), in gangrenous – 57 ± 18.5 U/l (p < 0.05).Conclusion. Determination of the concentration of GGTP and alkaline phosphatase in combination with other diagnostic criteria makes it possible to determine the presence of destructive forms of acute cholecystitis with high specificity and sensitivity before surgery

    Determining Absorption, Emissivity Reduction, and Local Suppression Coefficients inside Sunspots

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    The power of solar acoustic waves is reduced inside sunspots mainly due to absorption, emissivity reduction, and local suppression. The coefficients of these power-reduction mechanisms can be determined by comparing time-distance cross-covariances obtained from sunspots and from the quiet Sun. By analyzing 47 active regions observed by SOHO/MDI without using signal filters, we have determined the coefficients of surface absorption, deep absorption, emissivity reduction, and local suppression. The dissipation in the quiet Sun is derived as well. All of the cross-covariances are width corrected to offset the effect of dispersion. We find that absorption is the dominant mechanism of the power deficit in sunspots for short travel distances, but gradually drops to zero at travel distances longer than about 6 degrees. The absorption in sunspot interiors is also significant. The emissivity-reduction coefficient ranges from about 0.44 to 1.00 within the umbra and 0.29 to 0.72 in the sunspot, and accounts for only about 21.5% of the umbra's and 16.5% of the sunspot's total power reduction. Local suppression is nearly constant as a function of travel distance with values of 0.80 and 0.665 for umbrae and whole sunspots respectively, and is the major cause of the power deficit at large travel distances.Comment: 14 pages, 21 Figure

    Triggering an eruptive flare by emerging flux in a solar active-region complex

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    A flare and fast coronal mass ejection originated between solar active regions NOAA 11514 and 11515 on July 1, 2012 in response to flux emergence in front of the leading sunspot of the trailing region 11515. Analyzing the evolution of the photospheric magnetic flux and the coronal structure, we find that the flux emergence triggered the eruption by interaction with overlying flux in a non-standard way. The new flux neither had the opposite orientation nor a location near the polarity inversion line, which are favorable for strong reconnection with the arcade flux under which it emerged. Moreover, its flux content remained significantly smaller than that of the arcade (approximately 40 %). However, a loop system rooted in the trailing active region ran in part under the arcade between the active regions, passing over the site of flux emergence. The reconnection with the emerging flux, leading to a series of jet emissions into the loop system, caused a strong but confined rise of the loop system. This lifted the arcade between the two active regions, weakening its downward tension force and thus destabilizing the considerably sheared flux under the arcade. The complex event was also associated with supporting precursor activity in an enhanced network near the active regions, acting on the large-scale overlying flux, and with two simultaneous confined flares within the active regions.Comment: Accepted for publication in Topical Issue of Solar Physics: Solar and Stellar Flares. 25 pages, 12 figure

    Fucoidan-degrading fungal strains: screening, morphometric evaluation, and influence of medium composition

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    Ten different fungal strains from the genus Aspergillus, Penicillium, and Mucor were screened for fucoidan hydrolyzing ability aiming to find microorganisms able to produce sulfated fucan-degrading enzymes. Screening was carried out by measuring the strains kinetic and morphometric behavior over plate assays using Laminaria japonica fucoidan as only carbon source, testing three nitrogen sources (urea, peptone, and sodium nitrate). The selected fungal strains were subsequently used in submerged fermentations, which were performed for (1) selection of the strains able to growth over fucoidan medium and (2) media selection, testing the synergy of fucoidan with other sugars for inducing high enzyme titles. Radial expansion and hyphae parameters were observed for Aspergillus niger PSH, Mucor sp. 3P, and Penicillium purpurogenum GH2 grown only over fucoidan-urea medium. A. niger PSH showed the maximum enzymatic activity values, which were significantly different (p<0.05) from those achieved by the other selected fungi. Sucrose addition to fucoidan media proportioned the highest fucoidanase activity values for this fungal strain. This research allowed establishing optimal conditions for metabolites synthesis by fungal stains able to act toward fucoidan ramified matrix.Mexican Science and Technology Council (CONACYT

    Lifetimes of High-Degree p Modes in the Quiet and Active Sun

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    We study variations of the lifetimes of high-degree solar p-modes in the quiet and active Sun with the solar activity cycle. The lifetimes in the degree range 300 - 600 and frequency 2.5 - 4.5 mHz were computed from SOHO/MDI data in an area including active regions and quiet Sun using the time-distance technique. We applied our analysis to the data in four different phases of solar activity: in 1996 (at minimum), 1998 (rising phase), 2000 (at maximum) and 2003 (declining phase). The results from the area with active regions show that the lifetime decreases as activity increases. The maximal lifetime variations are between solar minimum in 1996 and maximum in 2000; the relative variation averaged over all mode degree values and frequencies is a decrease of about 13%. The lifetime reductions relative to 1996 are about 7% in 1998 and about 10% in 2003. The lifetime computed in the quiet region still decreases with solar activity although the decrease is smaller. On average, relative to 1996, the lifetime decrease is about 4% in 1998, 10% in 2000 and 8% in 2003. Thus, measured lifetime increases when regions of high magnetic activity are avoided. Moreover, the lifetime computed in quiet regions also shows variations with activity cycle.Comment: 13 pages, 5 figures; Accepted for publication in Solar Physic

    Abel Symposia

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    Discrete Morse theory has recently lead to new developments in the theory of random geometric complexes. This article surveys the methods and results obtained with this new approach, and discusses some of its shortcomings. It uses simulations to illustrate the results and to form conjectures, getting numerical estimates for combinatorial, topological, and geometric properties of weighted and unweighted Delaunay mosaics, their dual Voronoi tessellations, and the Alpha and Wrap complexes contained in the mosaics
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