89 research outputs found

    Limit distributions of two-dimensional quantum walks

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    One-parameter family of discrete-time quantum-walk models on the square lattice, which includes the Grover-walk model as a special case, is analytically studied. Convergence in the long-time limit t→∞t \to \infty of all joint moments of two components of walker's pseudovelocity, Xt/tX_t/t and Yt/tY_t/t, is proved and the probability density of limit distribution is derived. Dependence of the two-dimensional limit density function on the parameter of quantum coin and initial four-component qudit of quantum walker is determined. Symmetry of limit distribution on a plane and localization around the origin are completely controlled. Comparison with numerical results of direct computer-simulations is also shown.Comment: v3: REVTeX4, 20 pages, 6 figures, minor corrections made for publicatio

    The electronic state of vortices in YBa2Cu3Oy investigated by complex surface impedance measurement

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    The electromagnetic response to microwaves in the mixed state of YBa2Cu3Oy(YBCO) was measured in order to investigate the electronic state inside and outside the vortex core. The magnetic-field dependence of the complex surface impedance at low temperatures was in good agreement with a general vortex dynamics description assuming that the field-independent viscous damping force and the linear restoring force were acting on the vortices. In other words, both real and imaginary parts of the complex resistivity, \rho_1, and \rho_2, were linear in B. This is explained by theories for d-wave superconductors. Using analysis based on the Coffey-Clem description of the complex penetration depth, we estimated that the vortex viscosity \eta at 10 K was (4 \sim 5) \times 10^{-7} Ns/m^2. This value corresponds to \omega_0 \tau \sim 0.3 - 0.5, where \omega_0 and \tau are the minimal gap frequency and the quasiparticle lifetime in the vortex core, respectively. These results suggest that the vortex core in YBCO is in the moderately clean regime. Investigation of the moderately clean vortex core in high-temperature superconductors is significant because physically new effects may be expected due to d-wave characteristics and to the quantum nature of cuprate superconductors. The behavior of Z_s as a function of B across the first order transition (FOT) of the vortex lattice was also investigated. Unlike Bi2Sr2CaCu2Oy (BSCCO), no distinct anomaly was observed around the FOT in YBCO. Our results suggest that the rapid increase of X_s due to the change of superfluid density at the FOT would be observed only in highly anisotropic two-dimensional vortex systems like BSCCO. We discuss these results in terms of the difference of the interlayer coupling and the energy scale between the two materials.Comment: 10 pages, 6 figures, to be published in Phys. Rev. B, one reference adde

    Supplemental Information 2: Example dataset description

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    Access to consistent, high-quality metadata is critical to finding, understanding, and reusing scientific data. However, while there are many relevant vocabularies for the annotation of a dataset, none sufficiently captures all the necessary metadata. This prevents uniform indexing and querying of dataset repositories. Towards providing a practical guide for producing a high quality description of biomedical datasets, the W3C Semantic Web for Health Care and the Life Sciences Interest Group (HCLSIG) identified Resource Description Framework (RDF) vocabularies that could be used to specify common metadata elements and their value sets. The resulting guideline covers elements of description, identification, attribution, versioning, provenance, and content summarization. This guideline reuses existing vocabularies, and is intended to meet key functional requirements including indexing, discovery, exchange, query, and retrieval of datasets, thereby enabling the publication of FAIR data. The resulting metadata profile is generic and could be used by other domains with an interest in providing machine readable descriptions of versioned datasets

    Outcomes and factors influencing survival in cirrhotic cases with spontaneous rupture of hepatocellular carcinoma: a multicenter study

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    <p>Abstract</p> <p>Background</p> <p>Spontaneous rupture is rare complication of hepatocellular carcinoma (HCC) with high mortality rate in cirrhotic cases. The aim of this study was to determine the factors influencing prognosis in cases of spontaneously ruptured HCC and to investigate the outcomes of the treatments employed, especially transcatheter arterial embolization (TAE).</p> <p>Methods</p> <p>A retrospective multicenter study was conducted in 48 cirrhotic patients with spontaneous rupture of HCC. Conservative treatment was employed in 32 patients (ConT group) and TAE was performed in 16 patients (TAE group).</p> <p>Results</p> <p>The median survival time (MST) in the ConT group was only 13.1 days and the survival rate was extremely poor: 59.4% at 7 days, 37.5% at 14 days, and 6.3% at 30 days. On the other hand, the MST in the TAE group was 244.8 days and the survival rate was 87.5% at 1 month, 56.3% at 3 months, 23.4% at 12 months, and 15.6% at 24 months. According to the results of univariate analyses, factors associated with poor hepatic function and poor suitability for TAE was important determinants of short-term death (less than 3 weeks) among the patients (<it>p </it>< 0.05). On the other hand, among the patients in whom initial TAE was successfully performed (<it>n </it>= 15), a multivariate analysis showed that a maximum tumor size not exceeding 7 cm was the only independent factor determining long-term survival (<it>p </it>= 0.0130).</p> <p>Conclusion</p> <p>Despite the inherent limitations of this retrospective study, TAE appears to be a useful treatment strategy for cirrhotic patients with spontaneous HCC rupture, as it yielded a longer survival period compared with conservative treatment in patients with ruptured HCC. Among the patients with ruptured HCC in whom initial TAE was successfully performed, the maximum tumor size was an important factor influencing survival.</p

    The health care and life sciences community profile for dataset descriptions

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    Access to consistent, high-quality metadata is critical to finding, understanding, and reusing scientific data. However, while there are many relevant vocabularies for the annotation of a dataset, none sufficiently captures all the necessary metadata. This prevents uniform indexing and querying of dataset repositories. Towards providing a practical guide for producing a high quality description of biomedical datasets, the W3C Semantic Web for Health Care and the Life Sciences Interest Group (HCLSIG) identified Resource Description Framework (RDF) vocabularies that could be used to specify common metadata elements and their value sets. The resulting guideline covers elements of description, identification, attribution, versioning, provenance, and content summarization. This guideline reuses existing vocabularies, and is intended to meet key functional requirements including indexing, discovery, exchange, query, and retrieval of datasets, thereby enabling the publication of FAIR data. The resulting metadata profile is generic and could be used by other domains with an interest in providing machine readable descriptions of versioned datasets

    The effect of regulatory T-cell depletion on the spectrum of organ-specific autoimmune diseases in nonobese diabetic mice at different ages.

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    The nonobese diabetic (NOD) mouse spontaneously develops several autoimmune diseases, including type 1 diabetes and to a lesser extent thyroiditis and sialitis. Imbalance between effector T cells (Teffs) and regulatory T cells (Tregs) has recently been proposed as a mechanism for the disease pathogenesis in NOD mice, but previous studies have shown the various outcomes by different timing and methods of Treg-depletion. This study was, therefore, designed to compare the consequences of Treg-depletion by the same method (anti-CD25 antibody) on the spectrum of organ-specific autoimmune diseases in NOD mice of different ages. Treg-depletion by anti-CD25 antibody at 10 days of age accelerated development of all three diseases we examined (insulitis/diabetes, thyroiditis, and sialitis); Treg-depletion at 4 weeks of age accelerated only diabetes but not thyroiditis or sialitis; and Treg-depletion at 12 weeks of age hastened only development of thyroiditis and exhibited little influence on diabetes or sialitis. Increased levels of insulin autoantibodies (IAA) were, however, observed in mice depleted of Tregs at 10 days of age, not in those at 4 weeks. Thus, the consequences of Treg-depletion on the spectrum of organ-specific autoimmune diseases depend on the timing of anti-CD25 antibody injection in NOD mice. Aging gradually tips balance between Teffs and Tregs toward Teff-dominance for diabetes, but this balance for thyroiditis and sialitis likely alters more intricately. Our data also suggest that the levels of IAA are not necessarily correlated with diabetes development

    Haploinsufficiency of interferon regulatory factor 4 strongly protects against autoimmune diabetes in NOD mice

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    Aims/hypothesis: Interferon regulatory factor (IRF)4 plays a critical role in lymphoid development and the regulation of immune responses. Genetic deletion of IRF4 has been shown to suppress autoimmune disease in several mouse models, but its role in autoimmune diabetes in NOD mice remains unknown. Methods: To address the role of IRF4 in the pathogenesis of autoimmune diabetes in NOD mice, we generated IRF4-knockout NOD mice and investigated the impact of the genetic deletion of IRF4 on diabetes, insulitis and insulin autoantibody; the effector function of T cells in vivo and in vitro; and the proportion of dendritic cell subsets. Results: Heterozygous IRF4-deficient NOD mice maintained the number and phenotype of T cells at levels similar to NOD mice. However, diabetes and autoantibody production were completely suppressed in both heterozygous and homozygous IRF4-deficient NOD mice. The level of insulitis was strongly suppressed in both heterozygous and homozygous IRF4-deficient mice, with minimal insulitis observed in heterozygous mice. An adoptive transfer study revealed that IRF4 deficiency conferred disease resistance in a gene-dose-dependent manner in recipient NOD/severe combined immunodeficiency mice. Furthermore, the proportion of migratory dendritic cells in lymph nodes was reduced in heterozygous and homozygous IRF4-deficient NOD mice in an IRF4 dose-dependent manner. These results suggest that the levels of IRF4 in T cells and dendritic cells are important for the pathogenesis of diabetes in NOD mice. Conclusions/interpretation: Haploinsufficiency of IRF4 halted disease development in NOD mice. Our findings suggest that an IRF4-targeted strategy might be useful for modulating autoimmunity in type 1 diabetes
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