240 research outputs found

    DeepInf: Social Influence Prediction with Deep Learning

    Full text link
    Social and information networking activities such as on Facebook, Twitter, WeChat, and Weibo have become an indispensable part of our everyday life, where we can easily access friends' behaviors and are in turn influenced by them. Consequently, an effective social influence prediction for each user is critical for a variety of applications such as online recommendation and advertising. Conventional social influence prediction approaches typically design various hand-crafted rules to extract user- and network-specific features. However, their effectiveness heavily relies on the knowledge of domain experts. As a result, it is usually difficult to generalize them into different domains. Inspired by the recent success of deep neural networks in a wide range of computing applications, we design an end-to-end framework, DeepInf, to learn users' latent feature representation for predicting social influence. In general, DeepInf takes a user's local network as the input to a graph neural network for learning her latent social representation. We design strategies to incorporate both network structures and user-specific features into convolutional neural and attention networks. Extensive experiments on Open Academic Graph, Twitter, Weibo, and Digg, representing different types of social and information networks, demonstrate that the proposed end-to-end model, DeepInf, significantly outperforms traditional feature engineering-based approaches, suggesting the effectiveness of representation learning for social applications.Comment: 10 pages, 5 figures, to appear in KDD 2018 proceeding

    Grosnaja ABCs: Magnesium isotope compositions

    Get PDF
    Three CAI's from the Grosnaja CV3 chondrite were analyzed for their magnesium isotopic compositions by the ion microprobe. The selected CAI's represent three distinct types: GR4(compact Type A), GR7(Type B) and GR2(Type C). Petrographic studies indicate that all three Grosnaja inclusions were subjected to secondary alterations. The Type A CAI GR4 is primarily composed of melilite with spinel and pyroxene occurring as minor phases. The rim of the inclusion does not exhibit distinct layered structure and secondary alteration products (garnet, Fe-rich olivine and Na-rich plagioclase) are present in some localized areas near the rim region. The average major element compositions of different mineral phases in GR4 are given. Preliminary REE data suggest a depletion of HREE relative to LREE by about a factor of 3 without any clear indication of interelement fractionation. The CAI GR7 has textural and minerological characteristics similar to Type B inclusions. The REE data show a pattern that is similar to Group 6 with enrichment in Eu and Yb. In addition, a depletion of HREE compared to LREE is also evident in this object. Melilite composition shows a broad range of akermanite content (Ak(sub 15-55)). Detailed petrographic study is in progress. GR2 is a anorthite-rich Type C inclusion with large plagioclase laths intergrown with Ti-rich pyroxene. The average plagioclase composition is close to pure anorthite (An99)

    Corrosion of diffusion zinc coatings in sodium chloride solutions

    Get PDF
    Diffusion galvanizing is widely used in the pipe industry for coating the threaded surface of pipe couplings, protecting water and gas pipelines, and other metal products. Diffusion coatings have a number of advantages over other types of zinc coatings. In this work, electrochemical and gravimetric methods are used to study the corrosion behavior of diffusion zinc coatings in sodium chloride solutions. The corrosion rate depends non-linearly on the thickness of the coating. At the initial stages, the corrosion rate of coatings depends on the structure of the phases on the surface, and with an increase in the holding time, the corrosion rate depends to a greater extent on the properties of the products formed during the corrosion process. Films of corrosion products of diffusion zinc coatings consist of zinc oxide/hydroxide and basic zinc salts, while the composition of the film changes with increasing coating thickness

    Composition and structure of tungsten antimony acid

    Get PDF
    Tungsten antimony acids (TAA) with the composition H(2)Sb(2)WXO6·nH2O (0 < x ≤ 1.45; 0 < n ≤ 2.0) have been synthesized by hydrolysis of antimony trichloride pre-oxidized with nitric acid in the presence of varying amounts of Na2WO4. To obtain TAA protonated forms, the samples were kept in a 96% solution of sulphuric acid, the precipitate was washed until reaction became neutral and dried in air. The amount of tungsten, antimony, and silver ions in TAA was determined using energy dispersive analysis. Changes in structural parameters upon doping of AA with tungsten ions were studied using a Bruker D8 ADVANCE X-ray diffractometer (CuKa1-radiation). The number of oxonium ions in TAA was determined by the substitution of these ions by silver ions in equivalent amounts (Ag+-TAA forms). All obtained TAA samples and Ag+ TAA forms had a pyrochlore-type structure, space group symmetry Fd3m. Refinement of the arrangement of atoms in the structure using the Rietveld method showed that tungsten ions replace antimony ions and are statistically located in 16c, oxygen anions in 48f, and oxonium ions and water molecules in 16d and 8b positions, respectively. When tungsten ions were introduced into samples, the structural parameters of the resulting phases changed. There was a decrease in the unit cell parameter and the distance between antimony ions and oxygen anions, while an increase in the distance between oxonium ions and oxygen anions located in 48f positions was observed. This allowed the removal of a proton from oxonium molecules and its transport via a system of hydrogen bonds formed by water molecule

    Изучение влияния наночастиц серебра in vitro на уровень экспрессии молекулярных маркеров активации лимфоцитов и маркера аутоиммунного процесса периферической крови больных вирусной патологией роговицы

    Get PDF
    Изучено влияние in vitro наночастиц серебра на экспрессию молекулярных маркеров активации лимфоидных клеток СD 7+, CD 25+, CD 38+, CD 45+, CD 54+, CD 95+, CD 150+ и маркера аутоиммунного процесса CD 5+, а также на фагоцитарную активность нейтрофилов у больных с вирусной патологией роговицы. В лаборатории иммунологии ГУ «Институт глазных болезней и тканевой терапии им. В.П. Филатова НАМН Украины» была разработана методика культивирования лимфоцитов периферической крови с иммуномодулирующими препаратами, с последующим определением изменения уровня экспрессии молекулярных маркеров активации лимфоцитов. Оценка уровня экспрессии молекулярных маркеров активации лимфоцитов периферической крови проводилась гистоиммуноцитохимическим методом, с использованием панели моноклональных антител CD 5+, СD 7+, CD 25+, CD 38+, CD 45+, CD 54+, CD 95+ и CD 150+. Исследование было проведено in vitro с лимфоцитами периферической крови 23 больных вирусной патологией роговой оболочки глаза. Проведенные нами исследования по изучению воздействия in vitro частиц наносеребра на состояние экспрессии молекулярных маркеров активации лимфоцитов периферической крови и фагоцитарную активность нейтрофилов у больных с вирусной патологией роговицы, показали достоверное повышение уровня экспрессии СD7+, CD 25+, CD 45+ и фагоцитарной активности нейтрофилов после применения наночастиц серебра

    PHOTODYNAMIC DIAGNOSIS AND FLUORESCENCE SPECTROSCOPY IN SUPERFICIAL BLADDER CANCER

    Get PDF
    A comprehensive fluorescence technique has been developed to study the urinary bladder mucosa in patients with superficial bladder cancer (BC), by using alasense, white light cystoscopy, fluorescence cytoscopy, and local fluorescence spectroscopy in vivo. Quantification of urothelium fluorescence in the red emission foci of 5-ALA-induced protophorphyrin, with the local autofluorescence intensity being borne in mind, has been shown to increase the specificity of photodynamic diagnosis of superficial BC from 70 to 85% (p ≤ 0.05) and the total accuracy of the technique from 80 to 86%

    Quantum Phase Interference for Quantum Tunneling in Spin Systems

    Get PDF
    The point-particle-like Hamiltonian of a biaxial spin particle with external magnetic field along the hard axis is obtained in terms of the potential field description of spin systems with exact spin-coordinate correspondence. The Zeeman energy term turns out to be an effective gauge potential which leads to a nonintegrable pha se of the Euclidean Feynman propagator. The phase interference between clockwise and anticlockwise under barrier propagations is recognized explicitly as the Aharonov-Bohm effect. An additional phase which is significant for quantum phase interference is discovered with the quantum theory of spin systems besides the known phase obtained with the semiclassical treatment of spin. We also show the energ y dependence of the effect and obtain the tunneling splitting at excited states with the help of periodic instantons.Comment: 19 pages, no figure, to appear in PR

    Level splittings in exchange-biased spin tunneling

    Full text link
    The level splittings in a dimer with the antiferromagnetic coupling between two single-molecule magnets are calculated perturbatively for arbitrary spin. It is found that the exchange interaction between two single-molecule magnets plays an important role in the level splitting. The results are discussed in comparison with the recent experiment.Comment: 12 pages, to be published in Phys. Rev.

    Digital receivers for low-frequency radio telescopes UTR-2, URAN, GURT

    Full text link
    This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. This paper describes digital radio astronomical receivers used for decameter and meter wavelength observations. Since 1998, digital receivers performing on-the-fly dynamic spectrum calculations or waveform data recording without data loss have been used at the UTR-2 radio telescope, the URAN VLBI system, and the GURT new generation radio telescope. Here we detail these receivers developed for operation in the strong interference environment that prevails in the decameter wavelength range. Data collected with these receivers allowed us to discover numerous radio astronomical objects and phenomena at low frequencies, a summary of which is also presented.Comment: 24 pages, 15 figure
    corecore