618 research outputs found

    An Algorithm for the Set of All Generators of an Arbitrary Firing Count Vector in Petri Nets

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    In this paper, an effective method to obtain all nonnegative integer minimal support vectors (U4,V4) at level 4 for an arbitrary homogeneous / inhomogeneous solution of a matrix equation A x = b (A∈Zmxn, b∈Zmxl) starting from nonnegative rational number minimal support vectors (U3,V3) at level 3 is proposed. Although V4 has been derived from all minimal vectors (U5,V5) of level 5 which are obtained starting from vectors at levell, 2, or 3, so far, this proposed method for (U4,V4) gives us a big shortcut comparing with them. However, it is pointed out that obtaining (U5,V5) of level 5 from (U4,V4) of level 4 is difficult

    Magneto-Hydrodynamics of Population III Star Formation

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    Jet driving and fragmentation process in collapsing primordial cloud are studied using three-dimensional MHD nested grid simulations. Starting from a rotating magnetized spherical cloud with the number density of n=10^3 cm^-3, we follow the evolution of the cloud up to the stellar density n=10^22 cm^-3. We calculate 36 models parameterizing the initial magnetic and rotational energies (\gamma_0, \beta_0). In the collapsing primordial clouds, the cloud evolutions are characterized by the ratio of the initial rotational to magnetic energy, \gamma_0/\beta_0. The Lorentz force significantly affects the cloud evolution when \gamma_0 > \beta_0, while the centrifugal force is more dominant than the Lorentz force when \beta_0 > \gamma_0. When the cloud rotates rapidly with angular velocity of \Omega_0 > 10^-17 (n/10^3 cm^-3)^2/3 s^-1 and \beta_0 > \gamma_0, fragmentation occurs before the protostar is formed, but no jet appears after the protostar formation. On the other hand, a strong jet appears after the protostar formation without fragmentation when the initial cloud has the magnetic field of B_0 > 10^-9 (n/10^3 cm^-3)^2/3 G and \gamma_0 > \beta_0. Our results indicate that proto-Population III stars frequently show fragmentation and protostellar jet. Population III stars are therefore born as binary or multiple stellar systems, and they can drive strong jets, which disturb the interstellar medium significantly, as well as in the present-day star formation, and thus they may induce the formation of next generation stars.Comment: 37 pages, 10 figures, Submitted to ApJ, For high resolution figures, see http://astro3.sci.hokudai.ac.jp/~machida/astro-ph.pd

    Comparison of Hepatitis B Virus DNA, RNA, and Core Related Antigen as Predictors of Lamivudine Resistance in Patients with Chronic Hepatitis B

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    The clinical usefulness of hepatitis B virus (HBV)DNA, RNA, and core related antigen (HBcrAg)assays for predicting the appearance of HBV DNA breakthrough was evaluated and compared in patients with chronic hepatitis B undergoing lamivudine therapy.Methods :Thirty six patients with chronic hepatitis B who received lamivudine therapy for more than 1 year were enrolled. HBV RNA was measured simultaneously with HBV DNA (HBV RNA/DNA) using a real-time detection polymerase chain reaction assay with a preceding step of reverse-transcription. HBV DNA was measured by an HBV AMPLICOR monitor kit. HBcrAg was measured using a chemiluminescence enzyme immunoassay. Results : Sixteen patients (44%) developed HBV DNA breakthrough during the median observation period of 48.4 months (range 7.4-87.8 months). Afterwards, HBV DNA breakthrough was prospected using the three parameters taken 6 months after starting lamivudine therapy. The cut-offlevels for predictions were determined by receiver operating characteristic curves, and were 2.6 log copies/ml for HBV DNA, 3.8 log U/ml for HBV RNA/DNA, and 4.0 log U/ml for HBcrAg.Sensitivity,specificity,and accuracy for predicting HBV DNA breakthrough were 25%, 100%,and 67% respectively for HBV DNA.Similarly,they were 50%,90%,and 72% for HBV RNA/DNA, and 100%, 40%, and 67% for HBcrAg. Conclusion : Our findings confirm that HBV DNA is useful for identifying patients who are at high risk for HBV breakthrough.HBcrAg is useful for isolating those who are at low risk, and HBV RNA/DNA showed predictive characteristics similar to HBV DNA with higher sensitivity and the highest accuracyArticle信州医学雑誌, 58(4):153-162 (2010)departmental bulletin pape

    A highly efficient sublimation purification system using baffles with orifices

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    Here we report a highly efficient sublimation purification system using baffles with orifices in the sublimation tube. It is clearly demonstrated that the purity of materials is increased largely by introducing some pieces of baffles with orifices in the high-temperature region (sublimation region), which was confirmed by comparing the melting point (T-m) and the high-performance liquid chromatography (HPLC) purity with those of purified one by a conventional system. The driving voltages of electroluminescence (EL) devices were also compared and showed the same tendency with the T-m and HPLC purity data. Not only the purity but also the effective yield of purified materials was also increased by introducing baffles in low-temperature region. Some expected mechanisms of improving the purification efficiency by introducing baffles were also discussed.ArticleOrganic Electronics. 11(5):794-800 (2010)journal articl

    Abnormal systolic blood pressure response during exercise is related to subendocardial hypoperfusion detected by exercise 201Tl myocardial scintigraphy in patient with hypertrophic cardiomyopathy

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    Balcells, EugèniaPla general, d'alguns dels elements que formen la taula periòdica. Cadascun dels 112 elements és representat pel seu espectre de color. Es van produir diverses còpies de l'obra, aquesta està a la Biblioteca de la Facultat de Química

    The Nutritional Status of Japanese Black Breeding Cows Grazed in a Larger Abandoned Paddy Field

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    Because rice consumption has decreased in Japan, the number of abandoned paddy fields has increased. Some of the abandoned paddy fields are being used for livestock grazing, effectively using the abandoned fields and reducing the production costs on livestock farms. Such grazing may use an integrated grazing system of scattered small pastures where each of the small abandoned paddy fields scattered in a given agriculture area is defined as one grazing yard, and a herd consisting of two or three head of cattle is moved from one grazing yard to another. However, because the number of abandoned paddy fields has increased, it may be possible to have cattle grazing in larger fields made by combining multiple abandoned paddy fields (Shindo and Tejima 2006). Here we examined the nutritional status of Japanese Black breeding cows that stayed in larger-sized abandoned paddy fields to graze from spring to autumn

    Hepatitis B virus RNA is measurable in serum and can be a new marker for monitoring lamivudine therapy

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    The original publication is available at www.springerlink.comArticleJOURNAL OF GASTROENTEROLOGY. 41(8): 785-790 (2006)journal articl

    ss- and dxyd_{xy}-wave components induced around a vortex in dx2y2d_{x^2-y^2}-wave superconductors

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    Vortex structure of dx2y2d_{x^2-y^2}-wave superconductors is microscopically analyzed in the framework of the quasi-classical Eilenberger equations. If the pairing interaction contains an ss-wave (dxyd_{xy}-wave) component in addition to a dx2y2d_{x^2-y^2}-wave component, the ss-wave (dxyd_{xy}-wave) component of the order parameter is necessarily induced around a vortex in dx2y2d_{x^2-y^2}-wave superconductors. The spatial distribution of the induced ss-wave and dxyd_{xy}-wave components is calculated. The ss-wave component has opposite winding number around vortex near the dx2y2d_{x^2-y^2}-vortex core and its amplitude has the shape of a four-lobe clover. The amplitude of dxyd_{xy}-component has the shape of an octofoil. These are consistent with results based on the GL theory.Comment: RevTex,9 pages, 6 figures in a uuencoded fil

    Perfusion MRI for brain tumors

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    Purpose : To compare data on brain tumors derived from intravoxel incoherent motion (IVIM) and arterial spin labeling (ASL) imaging with multiple parameters obtained on dynamic susceptibility contrast (DSC) perfusion MRI and to clarify the characteristics of IVIM and ASL perfusion data from the viewpoint of cerebral blood flow (CBF) analysis. Methods : ASL-CBF and IVIM techniques as well as DSC examination were performed in 24 patients with brain tumors. The IVIM data were analyzed with the two models. The relative blood flow (rBF), relative blood volume (rBV) corrected relative blood volume (crBV), mean transit time (MTT), and leakage coefficient (K2) were obtained from the DSC MRI data. Results : The ASL-CBF had the same tendency as the perfusion parameters derived from the DSC data, but the permeability from the vessels had less of an effect on the ASL-CBF. The diffusion coefficient of the fast component on IVIM contained more information on permeability than the f value. Conclusion : ASL-CBF is more suitable for the evaluation of perfusion in brain tumors than IVIM parameters. ASL-CBF and IVIM techniques should be carefully selected and the biological significance of each parameter should be understood for the correct comprehension of the pathological status of brain tumors
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