10 research outputs found

    Deformations of nearly Kähler instantons

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    We formulate the deformation theory for instantons on nearly Kähler six-manifolds using spinors and Dirac operators. Using this framework we identify the space of deformations of an irreducible instanton with semisimple structure group with the kernel of an elliptic operator, and prove that abelian instantons are rigid. As an application, we show that the canonical connection on three of the four homogeneous nearly Kähler six-manifolds G/H is a rigid instanton with structure group H. In contrast, these connections admit large spaces of deformations when regarded as instantons on the tangent bundle with structure group SU(3)

    Copyright terms in online creative communities

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    M.: Addressing users’ privacy concerns for improving personalization quality: Towards an integration of user studies and algorithm evaluation

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    Abstract. Numerous studies have demonstrated the effectiveness of personalization using quality criteria both from machine learning / data mining and from user studies. However, a site requires more than a high-performance personalization algorithm: it needs to convince its users to input the data needed by the algorithm. Today’s Web users are becoming increasingly privacyconscious and less willing to disclose personal data. How can the advantages of personalization (and hence, of disclosure) be communicated effectively, and how can the success of such strategies be measured in terms of improved personalization quality? In this paper, we argue for a tighter integration of the HCI and computational issues involved in these questions. We first outline the problems for personalization that arise from the combination of users ’ privacy concerns and sites ’ current policies of dealing with privacy issues. We then describe the results of an experiment that investigated the effects of changes to a site’s interface on users ’ willingness to disclose data for personalization. This is followed by an overview of studies of the sensitivity of mining algorithms t

    Privacy-Enhanced Web Personalization

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    Abstract. Consumer studies demonstrate that online users value personalized content. At the same time, providing personalization on websites seems quite profitable for web vendors. This win-win situation is however marred by privacy concerns since personalizing people's interaction entails gathering considerable amounts of data about them. As numerous recent surveys have consistently demonstrated, computer users are very concerned about their privacy on the Internet. Moreover, the collection of personal data is also subject to legal regulations in many countries and states. Both user concerns and privacy regulations impact frequently used personalization methods. This article analyzes the tension between personalization and privacy, and presents approaches to reconcile the both. It has been tacitly acknowledged for many years that personalized interaction and user modeling have significant privacy implications, due to the fact that large amounts of personal information about users needs to be collected to perform personalization. Fo

    Inherited variants affecting RNA editing may contribute to ovarian cancer susceptibility: results from a large-scale collaboration

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    RNA editing in mammals is a form of post-transcriptional modification in which adenosine is converted to inosine by the adenosine deaminases acting on RNA (ADAR) family of enzymes. Based on evidence of altered ADAR expression in epithelial ovarian cancers (EOC), we hypothesized that single nucleotide polymorphisms (SNPs) in ADAR genes modify EOC susceptibility, potentially by altering ovarian tissue gene expression. Using directly genotyped and imputed data from 10,891 invasive EOC cases and 21,693 controls, we evaluated the associations of 5,303 SNPs in ADAD1, ADAR, ADAR2, ADAR3, and SND1. Unconditional logistic regression was used to estimate odds ratios (OR) and 95% confidence intervals (CI), with adjustment for European ancestry. We conducted gene-level analyses using the Admixture Maximum Likelihood (AML) test and the Sequence-Kernel Association test for common and rare variants (SKAT-CR). Association analysis revealed top risk-associated SNP rs77027562 (OR (95% CI)= 1.39 (1.17-1.64), P=1.0x10-4) in ADAR3 and rs185455523 in SND1 (OR (95% CI)= 0.68 (0.56-0.83), P=2.0x10-4). When restricting to serous histology (n=6,500), the magnitude of association strengthened for rs185455523 (OR=0.60, P=1.0x10-4). Gene-level analyses revealed that variation in ADAR was associated (P<0.05) with EOC susceptibility, with PAML=0.022 and PSKAT-CR=0.020. Expression quantitative trait locus analysis in EOC tissue revealed significant associations (P<0.05) with ADAR expression for several SNPs in ADAR, including rs1127313 (G/A), a SNP in the 3' untranslated region. In summary, germline variation involving RNA editing genes may influence EOC susceptibility, warranting further investigation of inherited and acquired alterations affecting RNA editing

    Phospholipase D

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