1,901 research outputs found

    Human pol II promoter prediction: time series descriptors and machine learning

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    Although several in silico promoter prediction methods have been developed to date, they are still limited in predictive performance. The limitations are due to the challenge of selecting appropriate features of promoters that distinguish them from non-promoters and the generalization or predictive ability of the machine-learning algorithms. In this paper we attempt to define a novel approach by using unique descriptors and machine-learning methods for the recognition of eukaryotic polymerase II promoters. In this study, non-linear time series descriptors along with non-linear machine-learning algorithms, such as support vector machine (SVM), are used to discriminate between promoter and non-promoter regions. The basic idea here is to use descriptors that do not depend on the primary DNA sequence and provide a clear distinction between promoter and non-promoter regions. The classification model built on a set of 1000 promoter and 1500 non-promoter sequences, showed a 10-fold cross-validation accuracy of 87% and an independent test set had an accuracy >85% in both promoter and non-promoter identification. This approach correctly identified all 20 experimentally verified promoters of human chromosome 22. The high sensitivity and selectivity indicates that n-mer frequencies along with non-linear time series descriptors, such as Lyapunov component stability and Tsallis entropy, and supervised machine-learning methods, such as SVMs, can be useful in the identification of pol II promoters

    Interpreting 750 GeV diphoton excess in SU(5) grand unified theory

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    The ATLAS and CMS experiments at the LHC have found significant excess in the diphoton invariant mass distribution near 750 GeV. We interpret this excess in a predictive nonsupersymmetric SU(5) grand unified framework with a singlet scalar and light adjoint fermions. The 750 GeV resonance is identified as a gauge singlet scalar. Both its production and decays are induced by 24 dimensional adjoint fermions predicted within SU(5). The adjoint fermions are assumed to be odd under Z2Z_2 symmetry which forbids their direct coupling to the standard model fermions. We show that the observed diphoton excess can be explained with sub-TeV adjoint fermions and with perturbative Yukawa coupling. A narrow width scenario is more preferred while a simultaneous explanation of observed cross section and large total decay width requires some of the adjoint fermions lighter than 375 GeV. The model also provides a singlet fermion as a candidate of cold dark matter. The gauge coupling unification is achieved in the framework by introducing color sextet scalars while being consistent with the proton decay constraint.Comment: Discussion added, conclusion unchanged; Matches published version in Physics Letters

    Search for a doubly-charged boson in four lepton final states in type II seesaw

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    CMS and ATLAS have searched for a doubly-charged boson H±±H^{\pm\pm} which may arise from type II seesaw in the 7 TeV run at the LHC by considering pair or associated production of doubly-charged bosons under the assumption of degenerate triplet scalars. In this work, we consider non-degenerate triplet components with the mass gap ΔM140\Delta M \sim 1 - 40 GeV which leads to enhanced pair-production cross-sections of H±±H^{\pm\pm} added by the gauge decays of the heavier neutral and singly-charged bosons. We reevaluate the constraints in the ΔMMH++\Delta M-M_{H^{++}} plane depending on the triplet vacuum expectation value vΔv_\Delta in the type II seesaw model which are much more stringent than the current search limits. We further study the possibility of observing same-sign tetra-lepton signals in the allowed parameter space which can be probed in the future runs of the LHC.Comment: 15 pages, 13 figure

    CP violation in tbW couplings at the LHC

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    We study in a model-independent way anomalous CP-violating tbW effective couplings that might arise from new physics in the processes pp-> tW^- X and pp-> tbar W^+X, followed by semileptonic decay of t and tbar. These processes have a dependence on effective tbW couplings both in the production process as well as in the decay of the t or tbar. We propose several CP-violating asymmetries constructed out of variables in the two processes, including t and tbar polarization, and energy and azimuthal angles of the decay particles. We find that it is feasible to probe a certain CP-violating combination of anomalous couplings at the per cent level at the LHC for centre-of-mass energy 14 TeV and an integrated luminosity of 10 fb^{-1}.Comment: 12 pages, 2 Figure

    A light triplet boson and Higgs-to-diphoton in supersymmetric type II seesaw

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    The supersymmetric type II seesaw may leave a limit where a triplet boson along with the standard Higgs boson remains light. Working in this limit with small triplet vacuum expectation vlaues, we explore how much such a light triplet boson can contribute to the Higgs boson decay to diphoton, and analyze the feasibility to observe it through same-sign di-lepton and tetra-lepton signals in the forthcoming LHC run after setting a LHC7 limit in a simplified parameter space of the triplet vaccum expectation value and the doubly charged boson mass.Comment: Addition of the Higgs decay to the doubly charged bosons and more reference

    Evaluation of management of malunited supracondylar fracture of humerus by lateral closing wedge osteotomy

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    Background: Various osteotomies have been in use for correction of varus deformity at elbow secondary to malunited supracondylar humerus fracture in children. The objectives of the study were to determine the efficacy & outcome of lateral closing wedge osteotomy in children as a treatment of malunited supracondylar fracture of humerus with cubitus varus and to evaluate various technical problems, morbidity, complications of Lateral closing wedge osteotomy and to suggest ways to overcome them.Methods: This prospective study was conducted among 50 cases of malunited supracondylar fracture of humerus who visited in OPD during 1st September 2008 to 31st August 2010. After pre-operative assessment, lateral closing wedge osteotomy was done and fixed with two 3.5 mm screws, figure of eight tension band stainless steel wire and a supplemental lateral k-wire. Post operatively x-ray of patient was taken and carrying angle and range of movement were calculated. Patients were re-assessed at complete union.Results: Maximum patients were from the age group of 8 to 10 years- 22 cases, mean age 13.08 years, 80% male. Left (non-dominant) side was involved in 30 (60%) cases. Around 18% cases developed complications. 25 (50%) patients had no loss of range of movement and 2 (4%) had 16 to 20 degrees loss of range of movement. Almost 36 (72%) cases had excellent outcome, 11 (22%) cases had good outcome, 3 (6%) cases had poor outcome due to loss of fixation, 47 (94%) patients/parents were satisfied with the final outcome.Conclusions: Lateral closing wedge osteotomy with a lateral K-wire is a sound, cost-effective, technically less demanding modality of treatment for varus deformity due to malunited supracondylar fracture of humerus in children with minimum complications
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