61 research outputs found

    Many toric ideals generated by quadratic binomials possess no quadratic Gr\"obner bases

    Full text link
    Let GG be a finite connected simple graph and IGI_{G} the toric ideal of the edge ring K[G]K[G] of GG. In the present paper, we study finite graphs GG with the property that IGI_{G} is generated by quadratic binomials and IGI_{G} possesses no quadratic Gr\"obner basis. First, we give a nontrivial infinite series of finite graphs with the above property. Second, we implement a combinatorial characterization for IGI_{G} to be generated by quadratic binomials and, by means of the computer search, we classify the finite graphs GG with the above property, up to 8 vertices.Comment: 11 pages, 17 figures, Typos corrected, Reference adde

    Holonomic Gradient Descent and its Application to Fisher-Bingham Integral

    Full text link
    We give a new algorithm to find local maximum and minimum of a holonomic function and apply it for the Fisher-Bingham integral on the sphere SnS^n, which is used in the directional statistics. The method utilizes the theory and algorithms of holonomic systems.Comment: 23 pages, 1 figur

    Genomic insight into the developmental history of southern highbush blueberry populations

    Get PDF
    ハイブッシュブルーベリーに暖地適応性をもたらした遺伝要因を解明 --ゲノムに刻まれたブルーベリーの育種履歴--. 京都大学プレスリリース. 2020-09-07.Interspecific hybridization is a common breeding approach for introducing novel traits and genetic diversity to breeding populations. Southern highbush blueberry (SHB) is a blueberry cultivar group that has been intensively bred over the last 60 years. Specifically, it was developed by multiple interspecific crosses between northern highbush blueberry [NHB, Vaccinium corymbosum L. (2n = 4x = 48)] and low-chill Vaccinium species to expand the geographic limits of highbush blueberry production. In this study, we genotyped polyploid blueberries, including 105 SHB, 17 NHB, and 10 rabbiteye blueberry (RE) (Vaccinium virgatum Aiton), from the accessions planted at Poplarville, Mississippi, and accessions distributed in Japan, based on the double-digest restriction site-associated DNA sequencing. The genome-wide SNP data clearly indicated that RE cultivars were genetically distinct from SHB and NHB cultivars, whereas NHB and SHB were genetically indistinguishable. The population structure results appeared to reflect the differences in the allele selection strategies that breeders used for developing germplasm adapted to local climates. The genotype data implied that there are no or very few genomic segments that were commonly introgressed from low-chill Vaccinium species to the SHB genome. Principal component analysis-based outlier detection analysis found a few loci associated with a variable that could partially differentiate NHB and SHB. These SNP loci were detected in Mb-scale haplotype blocks and may be close to the functional genes related to SHB development. Collectively, the data generated in this study suggest a polygenic adaptation of SHB to the southern climate, and may be relevant for future population-scale genome-wide analyses of blueberry

    Drop on a Bent Fibre

    Full text link
    Inspired by the huge droplets attached on cypress tree leaf tips after rain, we find that a bent fibre can hold significantly more water in the corner than a horizontally placed fibre (typically up to three times or more). The maximum volume of the liquid that can be trapped is remarkably affected by the bending angle of the fibre and surface tension of the liquid. We experimentally find the optimal included angle (36\sim {36}{^\circ}) that holds the most water. Analytical and semi-empirical models are developed to explain these counter-intuitive experimental observations and predict the optimal angle. The data and models could be useful for designing microfluidic and fog harvesting devices

    Isorhamnetin Promotes 53BP1 Recruitment through the Enhancement of ATM Phosphorylation and Protects Mice from Radiation Gastrointestinal Syndrome

    Get PDF
    Flavonoids are a subclass of polyphenols which are attractive, due to possessing various physiological activities, including a radioprotective effect. Tumor suppressor p53 is a primary regulator in the radiation response and is involved in the pathogenesis of radiation injuries. In this study, we revealed that isorhamnetin inhibited radiation cell death, and investigated its action mechanism focusing on DNA damage response. Although isorhamnetin moderated p53 activity, it promoted phosphorylation of ataxia telangiectasia mutated (ATM) and enhanced 53BP1 recruitment in irradiated cells. The radioprotective effect of isorhamnetin was not observed in the presence of ATM inhibitor, indicating that its protective effect was dependent on ATM. Furthermore, isorhamnetin-treated mice survived gastrointestinal death caused by a lethal dose of abdominal irradiation. These findings suggested that isorhamnetin enhances the ATM-dependent DNA repair process, which is presumably associated with the suppressive effect against GI syndrome

    Clinical characteristics of DM-PM ILD

    Get PDF
    Background : Dermatomyositis (DM) and polymyositis (PM) often have association with interstitial lung disease (ILD) which have disease specific autoantibody. Methodology :We reviewed medical records of DM/PM associated ILD from January 2000 to December 2017 according to the autoantibody. Result : We identified 52 patients, of whom30 were antibody negative, 18 had anti aminoacyl-tRNA synthetases (ARS) antibodies and 4 had anti melanoma differentiation-associated gene (MDA)-5 antibody. In high resolution computed tomography (HRCT) of the chest, area of ground glass opacity (GGO), consolidation, and lung tip consolidation were more extensive in anti MDA-5 antibody positive patients (p=0.051, p=0.026, and p=0.027, respectively). Among laboratory findings, GOT had strong correlations with CPK (r=0.889, p<0.001), and LDH (r=0.910, p<0.001). Among roentgenographic findings, there were moderate correlations between GGO and consolidation (r=0.668, p<0.001), and between reticular shadow and traction bronchiectasis (p=0.633, p<0.001). ILD patients with anti MDA-5 antibodies had decreased survival (1.00 vs 84.3, 22.9 months, p<0.001). Conclusion : ILD patients with anti ARS antibody had intense inflammation, but reversible fibrosis and good prognosis. On the other hand, anti MDA-5 antibody positive ILD patients had shorter survival. Extent of parenchymal shadow and serum GOT were useful indicator of disease activity of PM/DM associated ILD patients in our cohort