74 research outputs found

    Neutron charge form factor at large q2q^2

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    The neutron charge form factor GEn(q)G_{En}(q) is determined from an analysis of the deuteron quadrupole form factor FC2F_{C2} data. Recent calculations, based on a variety of different model interactions and currents, indicate that the contributions associated with the uncertain two-body operators of shorter range are relatively small for FC2F_{C2}, even at large momentum transfer qq. Hence, GEn(q)G_{En}(q) can be extracted from FC2F_{C2} at large q2q^2 without undue systematic uncertainties from theory.Comment: 8 pages, 3 figure

    Systematic multi-omics cell line profiling uncovers principles of Ewing sarcoma fusion oncogene-mediated gene regulation

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    Ewing sarcoma (EwS) is characterized by EWSR1-ETS fusion transcription factors converting polymorphic GGAA microsatellites (mSats) into potent neo-enhancers. Although the paucity of additional mutations makes EwS a genuine model to study principles of cooperation between dominant fusion oncogenes and neo-enhancers, this is impeded by the limited number of well-characterized models. Here we present the Ewing Sarcoma Cell Line Atlas (ESCLA), comprising whole-genome, DNA methylation, transcriptome, proteome, and chromatin immunoprecipitation sequencing (ChIP-seq) data of 18 cell lines with inducible EWSR1-ETS knockdown. The ESCLA shows hundreds of EWSR1-ETS-targets, the nature of EWSR1-ETS-preferred GGAA mSats, and putative indirect modes of EWSR1-ETS-mediated gene regulation, converging in the duality of a specific but plastic EwS signature. We identify heterogeneously regulated EWSR1-ETS-targets as potential prognostic EwS biomarkers. Our freely available ESCLA (http://r2platform.com/escla/) is a rich resource for EwS research and highlights the power of comprehensive datasets to unravel principles of heterogeneous gene regulation by chimeric transcription factors

    Reversible transitions between noradrenergic and mesenchymal tumor identities define cell plasticity in neuroblastoma

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    Noradrenergic and mesenchymal identities have been characterized in neuroblastoma cell lines according to their epigenetic landscapes and core regulatory circuitries. However, their relationship and relative contribution in patient tumors remain poorly defined. We now document spontaneous and reversible plasticity between the two identities, associated with epigenetic reprogramming, in several neuroblastoma models. Interestingly, xenografts with cells from each identity eventually harbor a noradrenergic phenotype suggesting that the microenvironment provides a powerful pressure towards this phenotype. Accordingly, such a noradrenergic cell identity is systematically observed in single-cell RNA-seq of 18 tumor biopsies and 15 PDX models. Yet, a subpopulation of these noradrenergic tumor cells presents with mesenchymal features that are shared with plasticity models, indicating that the plasticity described in these models has relevance in neuroblastoma patients. This work therefore emphasizes that intrinsic plasticity properties of neuroblastoma cells are dependent upon external cues of the environment to drive cell identity

    Backward production in π−p→pfπ+π−π−\pi^{-}p \rightarrow p_{f}\pi^{+}\pi^{-}\pi^{-} reaction at 9 and 12 GeV/c

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    The authors have analyzed backward meson production in the reaction pi /sup -/p to p/sub f/ pi /sup +/ pi /sup -/ pi /sup -/ at 9 GeV/c and 12 GeV/c incident pi /sup -/ momenta, from an experiment performed at the CERN Omega Spectrometer using a fast proton (p/sub f/) trigger device. They find strong production of quasi-two-body processes N* rho and N*f with a production mechanism consistent with u-channel nucleon exchange. At a lower level, N* pi processes with a 3-body baryon decay through Delta (1232) pi are observed. In the (3 pi )/sup -/ system, evidence is found for A/sub 1//sup -/ and clear A/sub 2//sup -/ backward production with similar cross sections ( approximately 0.5 mu b). (16 refs)

    Backward omega /sup 0/ and eta /sup 0/ production in pi p interactions at 9 and 12 GeV/c

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    The backward production of omega /sup 0/ mesons in the u-channel I/sub u/=/sup 1///sub 2/ exchange reaction pi /sup -/p to N/sup 0/ (1680) omega /sup 0/ has been studied at 9 GeV/c and 12 GeV/c incident momenta. The data comes from an experiment performed at the CERN Omega Spectrometer using a fast proton trigger device. The backward production of the eta /sup 0/ meson has also been observed and the coupling constant ratio g/sub eta NN//g/sub pi NN/ has been estimated. (21 refs)
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