1,319 research outputs found

    Interior-point algorithm for shakedown analysis accounting for limited kinematical hardening

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    We present a numerical method for the computation of shakedown loads of structures under thermo-mechanical loading accounting for limited kinematical hardening. The method is based on the lower bound approach by Melan extended to the hardening using a two-surface model. Both the yield and the bounding surface are defined by the von Mises condition. Melan’s shakedown theorem leads to a nonlinear convex optimization problem. This is solved by the interior-point algorithm ipsa recently developed by the authors. In this paper, theoretical and numerical aspects will be presented as well as numerical examples from mechanical engineering

    Search for B0π0π0B^{0}\to \pi^{0}\pi^{0} Decay

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    We have searched for the charmless hadronic decay of B0 mesons into two neutral pions. Using 9.13fb^-1 taken at the Upsilon(4S) with the CLEO detector, we obtain an improved upper limit for the branching fraction BR(B0-->pi0pi0) < 5.7*10^-6 at the 90% confidence level.Comment: pages postscript, also available through http://w4.lns.cornell.edu/public/CLN

    Search for the Higgs boson in lepton, tau and jets final states

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    We present a search for the standard model Higgs boson in final states with an electron or muon and a hadronically decaying tau lepton in association with two or more jets using 9.7 fb^{-1} of Run II Fermilab Tevatron Collider data collected with the D0 detector. The analysis is sensitive to Higgs boson production via gluon fusion, associated vector boson production, and vector boson fusion, followed by the Higgs boson decay to tau lepton pairs or to W boson pairs. The ratios of 95% C.L. upper limits on the cross section times branching ratio to those predicted by the standard model are obtained for orthogonal subsamples that are enriched in either H -> tau tau decays or H -> WW decays, and for the combination of these subsample limits. The observed and expected limit ratios for the combined subsamples at a Higgs boson mass of 125 GeV are 11.3 and 9.0 respectively

    Histone deacetylases as new therapy targets for platinum-resistant epithelial ovarian cancer

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    Introduction: In developed countries, ovarian cancer is the fourth most common cancer in women. Due to the nonspecific symptomatology associated with the disease many patients with ovarian cancer are diagnosed late, which leads to significantly poorer prognosis. Apart from surgery and radiotherapy, a substantial number of ovarian cancer patients will undergo chemotherapy and platinum based agents are the mainstream first-line therapy for this disease. Despite the initial efficacy of these therapies, many women relapse; therefore, strategies for second-line therapies are required. Regulation of DNA transcription is crucial for tumour progression, metastasis and chemoresistance which offers potential for novel drug targets. Methods: We have reviewed the existing literature on the role of histone deacetylases, nuclear enzymes regulating gene transcription. Results and conclusion: Analysis of available data suggests that a signifant proportion of drug resistance stems from abberant gene expression, therefore HDAC inhibitors are amongst the most promising therapeutic targets for cancer treatment. Together with genetic testing, they may have a potential to serve as base for patient-adapted therapies

    Search for WHWH associated production in ppˉp \bar{p} collisions at s=1.96TeV\sqrt{s}=1.96\,{\rm TeV}

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    This report describes a search for associated production of WW and Higgs bosons based on data corresponding to an integrated luminosity of L\cal{L}5.3fb1 \approx 5.3 \rm fb^{-1} collected with the D0 detector at the Fermilab Tevatron ppˉp\bar{p} Collider. Events containing a WνW\rightarrow \ell \nu candidate (with \ell corresponding to ee or μ\mu) are selected in association with two or three reconstructed jets. One or two of the jets are required to be consistent with having evolved from a bb quark. A multivariate discriminant technique is used to improve the separation of signal and backgrounds. Expected and observed upper limits are obtained for the product of the WHWH production cross section and branching ratios and reported in terms of ratios relative to the prediction of the standard model as a function of the mass of the Higgs boson (MHM_{H}). The observed and expected 95% C.L. upper limits obtained for an assumed MH=115GeVM_{H}=115 \rm GeV are, respectively, factors of 4.5 and 4.8 larger than the value predicted by the standard model.Comment: 25 pages, 14 figure

    Measurement of the photon+b+b-jet production differential cross section in ppˉp\bar{p} collisions at \sqrt{s}=1.96~\TeV

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    We present measurements of the differential cross section dsigma/dpT_gamma for the inclusive production of a photon in association with a b-quark jet for photons with rapidities |y_gamma|< 1.0 and 30<pT_gamma <300 GeV, as well as for photons with 1.5<|y_gamma|< 2.5 and 30< pT_gamma <200 GeV, where pT_gamma is the photon transverse momentum. The b-quark jets are required to have pT>15 GeV and rapidity |y_jet| < 1.5. The results are based on data corresponding to an integrated luminosity of 8.7 fb^-1, recorded with the D0 detector at the Fermilab Tevatron ppˉp\bar{p} Collider at sqrt(s)=1.96 TeV. The measured cross sections are compared with next-to-leading order perturbative QCD calculations using different sets of parton distribution functions as well as to predictions based on the kT-factorization QCD approach, and those from the Sherpa and Pythia Monte Carlo event generators.Comment: 10 pages, 9 figures, submitted to Phys. Lett.

    Web-based scientific exploration and analysis of 3D scanned cuneiform datasets for collaborative research

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    The three-dimensional cuneiform script is one of the oldest known writing systems and a central object of research in Ancient Near Eastern Studies and Hittitology. An important step towards the understanding of the cuneiform script is the provision of opportunities and tools for joint analysis. This paper presents an approach that contributes to this challenge: a collaborative compatible web-based scientific exploration and analysis of 3D scanned cuneiform fragments. The WebGL -based concept incorporates methods for compressed web-based content delivery of large 3D datasets and high quality visualization. To maximize accessibility and to promote acceptance of 3D techniques in the field of Hittitology, the introduced concept is integrated into the Hethitologie-Portal Mainz, an established leading online research resource in the field of Hittitology, which until now exclusively included 2D content. The paper shows that increasing the availability of 3D scanned archaeological data through a web-based interface can provide significant scientific value while at the same time finding a trade-off between copyright induced restrictions and scientific usability

    Search for pair production of the scalar top quark in muon+tau final states

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    We present a search for the pair production of scalar top quarks (t~1\tilde{t}_{1}), the lightest supersymmetric partners of the top quarks, in ppˉp\bar{p} collisions at a center-of-mass energy of 1.96 TeV, using data corresponding to an integrated luminosity of {7.3 fb1fb^{-1}} collected with the \dzero experiment at the Fermilab Tevatron Collider. Each scalar top quark is assumed to decay into a bb quark, a charged lepton, and a scalar neutrino (ν~\tilde{\nu}). We investigate final states arising from t~1t~1ˉbbˉμτν~ν~\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\mu\tau \tilde{\nu} \tilde{\nu} and t~1t~1ˉbbˉττν~ν~\tilde{t}_{1} \bar{\tilde{t}_{1}} \rightarrow b\bar{b}\tau\tau \tilde{\nu} \tilde{\nu}. With no significant excess of events observed above the background expected from the standard model, we set exclusion limits on this production process in the (mt~1m_{\tilde{t}_{1}},mν~m_{\tilde{\nu}}) plane.Comment: Submitted to Phys. Lett.

    Seedling Establishment of Spartina alterniflora and Spartina patens on Dredged Materials in Texas

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    Effects of fertilizer, elevation, and tidal inundation on seedling establishment of Spartina alterniflora and Spartina patens were tested at a wave-protected sandy dredged material site, Galveston Bay, Texas. No seedlings that grew from sown seeds became established at elevations below 36 cm (msl) while the greatest number established in the upper tier. Seedlings of S. alterniflora were more numerous than S. patens in the upper and middle tiers. Naturally occurring seedlings of S. alterniflora, which apparently germinated from seeds produced on transplants in adjacent plots, established at all elevations of the site during winter. The average time of tidal inundation at a particular elevation was less during winter than spring. Thus, establishment of plants by seed at low intertidal elevations appears feasible only during low seasonal winter tides and with S. alterniflora. Fertilizers did not enhance growth, and high concentrations of fertilizer caused stress to some S. alterniflora seedlings
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