2,452 research outputs found

    Axial anomaly of QED in a strong magnetic field and noncommutative anomaly

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    The Adler-Bell-Jackiw (ABJ) anomaly of a 3+1 dimensional QED is calculated in the presence of a strong magnetic field. It is shown that in the regime with the lowest Landau level (LLL) dominance a dimensional reduction from D=4 to D=2 dimensions occurs in the longitudinal sector of the low energy effective field theory. In the chiral limit, the resulting anomaly is therefore comparable with the axial anomaly of a two dimensional massless Schwinger model. It is further shown that the U(1) axial anomaly of QED in a strong magnetic field is closely related to the ``nonplanar'' axial anomaly of a conventional noncommutative QED.Comment: 18 pp, no figure. v2: The version accepted to be publidhed in PR

    The power of implicit social relation in rating prediction of social recommender systems of social recommender

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    The explosive growth of social networks in recent times has presented a powerful source of information to be utilized as an extra source for assisting in the social recommendation problems. The social recommendation methods that are based on probabilistic matrix factorization improved the recommendation accuracy and partly solved the cold-start and data sparsity problems. However, these methods only exploited the explicit social relations and almost completely ignored the implicit social relations. In this article, we firstly propose an algorithm to extract the implicit relation in the undirected graphs of social networks by exploiting the link prediction techniques. Furthermore, we propose a new probabilistic matrix factorization method to alleviate the data sparsity problem through incorporating explicit friendship and implicit friendship. We evaluate our proposed approach on two real datasets, Last.Fm and Douban. The experimental results show that our method performs much better than the state-of-the-art approaches, which indicates the importance of incorporating implicit social relations in the recommendation process to address the poor prediction accuracy

    The Evaluation of Relationship Marketing of Skin Care Services at PKU Muhammadiyah YOGYAKARTA Hospital

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    Skin care is a service which is taken into account by PKU Muhammadiyah Yogyakarta hospital as a way to cope with the competition among the hospitals. PKU Muhammadiyah Yogyakarta skin care was established in July, 2010. In a year, visit amount had fluctuated. One fluctuated impact is negative evaluation of market because hospital can not control skin care service. marketing evaluation a principles on relationship marketing. Handled fluctuated way of marketing evaluation principled on relationship marketing. To evaluate of relationship marketing on skin care service in PKU Muhammadiyah Yogyakarta Hospital.  This research used a mixed method with design sequential explanatory. The subject quantitative is 112 respondents and subject qualitative is 7 respondents selected from subject quantitative. The data was taken from questionnaires and in-depth interviews. The data analysis is double linear regression. Communication have association on trust, commitment and relationship satisfaction.Relationship duration have association on commitment and relationship satisfaction. Interaction frequency have no association on trust. Commitment and relationship satisfaction have association on word of mouth. Factors affecting no customer commitment is customer must wait whereas did appoitment, beautician can not answer the question of customers, no drugs in pharmacy and no resulting skin care in PKU Muhammadiyah Yogyakarta Hospital. Commitment and relationship satisfaction have association on word of mouth. Communication and relationship duration can increase of commitment and relationship satisfactio

    Dynamic mechanical analysis of Dwimatrix Biopolymer from waste oil blended with thermoplastic; LDPE/HDPE

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    This paper presents results from an experimental study on the dynamic mechanical and viscoelastic properties of Biopolymer (BP) from Waste vegetable oils (WVO) blended with two types of thermoplastic polyethylene (PE) which are Low Density Polyethylene (LDPE) and High Density Polyethylene (HDPE). BP blended containing 10–30wt.% of BP were injection moulded. MDI were used as crosslinker agent for modifying the matrices. Dynamic mechanical analysis (DMA) of the blended were performed over a temperature range of 30–120°C for BL and 30-140°C for BH under frequency of 1 Hz. DMA revealed no noticeable changes in a-transition temperature when the BP content was increased or were added. The BP blended revealed better temperature resistance at higher BP content. However, the increase in storage modulus was negligible at BL10 and BH20; due to the agglomeration of the BP. The results of the damping ratio analysis revealed that higher interfacial bonding was achieved by addition of MDI crosslinker agent

    Deep UV Luminosity Functions at the Infall Region of the Coma Cluster

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    We have used deep GALEX observations at the infall region of the Coma cluster to measure the faintest UV luminosity functions (LFs) presented for a rich galaxy cluster thus far. The Coma UV LFs are measured to M_UV = -10.5 in the GALEX FUV and NUV bands, or 3.5 mag fainter than previous studies, and reach the dwarf early-type galaxy population in Coma for the first time. The Schechter faint-end slopes (alpha = -1.39 in both GALEX bands) are shallower than reported in previous Coma UV LF studies owing to a flatter LF at faint magnitudes. A Gaussian-plus-Schechter model provides a slightly better parametrization of the UV LFs resulting in a faint-end slope of ~ -1.15 in both GALEX bands. The two-component model gives faint-end slopes shallower than -1 (a turnover) for the LFs constructed separately for passive and star forming galaxies. The UV LFs for star forming galaxies show a turnover at M_UV ~ -14 owing to a deficit of dwarf star forming galaxies in Coma with stellar masses below M*=10^8 Msun. A similar turnover is identified in recent UV LFs measured for the Virgo cluster suggesting this may be a common feature of local galaxy clusters, whereas the field UV LFs continue to rise at faint magnitudes. We did not identify an excess of passive galaxies as would be expected if the missing dwarf star forming galaxies were quenched inside the cluster. In fact, the LFs for both dwarf passive and star forming galaxies show the same turnover at faint magnitudes. We discuss the possible origin of the missing dwarf star forming galaxies in Coma and their expected properties based on comparisons to local field galaxies.Comment: accepted for publication in Ap

    A model for time-dependent cosmological constant and its consistency with the present Friedmann universe

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    We use a model where the cosmological term can be related to the chiral gauge anomaly of a possible quantum scenario of the initial evolution of the universe. We show that this term is compatible with the Friedmann behavior of the present universe.Comment: 5 pages, Revtex 4, twocolumn (minor corrections and improved reference list. To appear in Classical and Quantum Gravity
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