7,556 research outputs found
Variational study of U(1) and SU(2) lattice gauge theories with Gaussian states in 1+1 dimensions
We introduce a method to investigate the static and dynamic properties of
both Abelian and non-Abelian lattice gauge models in 1+1 dimensions.
Specifically, we identify a set of transformations that disentangle different
degrees of freedom, and apply a simple Gaussian variational ansatz to the
resulting Hamiltonian. To demonstrate the suitability of the method, we analyze
both static and dynamic aspects of string breaking for the U(1) and SU(2) gauge
models. We benchmark our results against tensor network simulations and observe
excellent agreement, although the number of variational parameters in the
Gaussian ansatz is much smaller.Comment: 19 pages, 6 figures. Added references and corrected typo
Gaussian states for the variational study of (1+1)-dimensional lattice gauge models
We introduce a variational ansatz based on Gaussian states for
(1+1)-dimensional lattice gauge models. To this end we identify a set of
unitary transformations which decouple the gauge degrees of freedom from the
matter fields. Using our ansatz, we study static aspects as well as real-time
dynamics of string breaking in two (1+1)-dimensional theories, namely QED and
two-color QCD. We show that our ansatz captures the relevant features and is in
excellent agreement with data from numerical calculations with tensor networks.Comment: 7 pages, 2 figures, proceedings of the 36th Annual International
Symposium on Lattice Field Theory, 22-28 July, 2018 Michigan State
University, East Lansing, Michigan, US
Physical interaction between MYCN oncogene and polycomb repressive complex 2 (PRC2) in neuroblastoma: Functional and therapeutic implications
This article is made available through the Brunel Open Access Publishing Fund. © 2013 by The American Society for Biochemistry and Molecular Biology, Inc.CLU (clusterin) is a tumor suppressor gene that we have previously shown to be negatively modulated by the MYCN proto-oncogene, but the mechanism of repression was unclear. Here, we show that MYCN inhibits the expression of CLU by direct interaction with the non-canonical E box sequence CACGCG in the 5′-flanking region. Binding of MYCN to the CLU gene induces bivalent epigenetic marks and recruitment of repressive proteins such as histone deacetylases and Polycomb members. MYCN physically binds in vitro and in vivo to EZH2, a component of the Polycomb repressive complex 2, required to repress CLU. Notably, EZH2 interacts with the Myc box domain 3, a segment of MYC known to be essential for its transforming effects. The expression of CLU can be restored in MYCN-amplified cells by epigenetic drugs with therapeutic results. Importantly, the anticancer effects of the drugs are ablated if CLU expression is blunted by RNA interference. Our study implies that MYC tumorigenesis can be effectively antagonized by epigenetic drugs that interfere with the recruitment of chromatin modifiers at repressive E boxes of tumor suppressor genes such as CLU.SPARKS, The Neuroblastoma Society,
a Wellcome Trust grant (to A. S.), and the Italian Association for Cancer
Research
A new search for anomalous neutrino oscillations at the CERN-PS
The LSND experiment has observed a 3.8 sigma excess of anti-nu_e events from
an anti-nu_mu beam coming from pions at rest. If confirmed, the LSND anomaly
would imply new physics beyond the standard model, presumably in the form of
some additional sterile neutrinos. The MiniBooNE experiment at FNAL-Booster has
further searched for the LSND anomaly. Above 475 MeV, the nu_e result is
excluding the LSND anomaly to about 1.6 sigma but it introduces an unexplained,
new 3.0 sigma anomaly at lower energies, down to 200 MeV. The nu_e data have so
far an insufficient statistics to be conclusive with LSND's anti-nu_e. The
present proposal at the CERN-PS is based on two strictly identical LAr-TPC
detectors in the near and far positions, respectively at 127 and 850 m from the
neutrino (or antineutrino) target and focussing horn, observing the
electron-neutrino signal. This project will benefit from the already developed
technology of ICARUS T600, well tested on surface in Pavia, without the need of
any major R&D activity and without the added problems of an underground
experiment (CNGS-2). The superior quality of the Liquid Argon imaging TPC and
its unique electron - pi-zero discrimination allow full rejection of the NC
background, without efficiency loss for electron neutrino detection. In two
years of exposure, the far detector mass of 600 tons and a reasonable
utilization of the CERN-PS with the refurbished previous TT7 beam line will
allow to collect about 10^6 charged current events, largely adequate to settle
definitely the LSND anomaly.Comment: 23 pages, 17 figures, added watermark, better referencin
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