342 research outputs found

    Progress on the development of a three-dimensional capability for simulating large-scale complex geologic processes

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    Significant progress has been made in developing a three-dimensional capability for predicting the mechanical response of rock over spatial and time scales of geologic interest to the Oil and Gas industry. An Advanced Computational Technology Initiative (ACTI) initiated three years ago to achieve such a computational technology breakthrough has made significant progress towards its goal by adapting and improving the unique advanced quasistatic finite element technology developed by Sandia National Laboratories to the mechanics applications important to exploration and production (E and P). This capability now gives the industry a powerful tool to help reduce risk on prospects, improve pre-project initial reserve estimates, and lower operating costs. Progress to date on this program is reported herein by presenting and discussing the enhancements and adaptations that have been made to the technology, with specific examples to illustrate their use on large E and P geomechanics problems

    Estranged relations: coercion and care in narratives of supported decision-making in mental healthcare

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    Supported decision-making has become popular among policymakers and mental health advocates as a means of reducing coercion in mental healthcare. Nevertheless, users of psychiatric services often seem equivocal about the value of supported decision-making initiatives. In this paper we explore why such initiatives might be rejected or ignored by the would-be beneficiaries, and we reflect on broader implications for care and coercion. We take a critical medical humanities approach, particularly through the lens of entanglement. We analyse the narratives of 29 people diagnosed with mental illness, and 29 self-identified carers speaking of their experiences of an Australian mental healthcare system and of their views of supported decision-making. As a scaffolding for our critique we consider two supported decision-making instruments in the 2014 Victorian Mental Health Act: the advance statement and the nominated person. These instruments presuppose that patients and carers endorse a particular set of relationships between the agentic self and illness, as well as between patient, carer and the healthcare system. Our participant narratives instead conveyed ‘entangled’ relations, which we explore in three sections. In the first we show how ideas about fault and illness often coexisted, which corresponded with shifting views on the need for more versus less agency for patients. In the second section, we illustrate how family carers struggled to embody the supported decision-making ideal of the independent yet altruistic nominated person, and in the final section we suggest that both care and coercion were narrated as existing across informal/formal care divisions. We conclude by reflecting on how these dynamic relations complicate supported decision-making projects, and prompt a rethink of how care and coercion unfold in contemporary mental healthcare

    Disappearance of Ensemble-Averaged Josephson Current in Dirty SNS Junctions of d-wave Superconductors

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    We discuss the Josephson current in superconductor / dirty normal conductor / superconductor junctions, where the superconductors have dx2−y2d_{x^2-y^2} pairing symmetry. The low-temperature behavior of the Josephson current depends on the orientation angle between the crystalline axis and the normal of the junction interface. We show that the ensemble-averaged Josephson current vanishes when the orientation angle is π/4\pi/4 and the normal conductor is in the diffusive transport regime. The dx2−y2d_{x^2-y^2}-wave pairing symmetry is responsible for this fact.Comment: 8 pages, 5 figure

    Leptonic and Semileptonic Decays of Charm and Bottom Hadrons

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    We review the experimental measurements and theoretical descriptions of leptonic and semileptonic decays of particles containing a single heavy quark, either charm or bottom. Measurements of bottom semileptonic decays are used to determine the magnitudes of two fundamental parameters of the standard model, the Cabibbo-Kobayashi-Maskawa matrix elements VcbV_{cb} and VubV_{ub}. These parameters are connected with the physics of quark flavor and mass, and they have important implications for the breakdown of CP symmetry. To extract precise values of ∣Vcb∣|V_{cb}| and ∣Vub∣|V_{ub}| from measurements, however, requires a good understanding of the decay dynamics. Measurements of both charm and bottom decay distributions provide information on the interactions governing these processes. The underlying weak transition in each case is relatively simple, but the strong interactions that bind the quarks into hadrons introduce complications. We also discuss new theoretical approaches, especially heavy-quark effective theory and lattice QCD, which are providing insights and predictions now being tested by experiment. An international effort at many laboratories will rapidly advance knowledge of this physics during the next decade.Comment: This review article will be published in Reviews of Modern Physics in the fall, 1995. This file contains only the abstract and the table of contents. The full 168-page document including 47 figures is available at http://charm.physics.ucsb.edu/papers/slrevtex.p

    Lifetime Differences, direct CP Violation and Partial Widths in D0 Meson Decays to K+K- and pi+pi-

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    We describe several measurements using the decays D0->K+K- and pi+pi-. We find the ratio of partial widths, Gamma(D0->K+K-)/Gamma(D0->pi+pi-), to be 2.96+/-0.16+/-0.15, where the first error is statistical and the second is systematic. We observe no evidence for direct CP violation, obtaining A_CP(KK) = (0.0+/-2.2+/-0.8)% and A_CP(pipi = (1.9+/-3.2+/-0.8)%. In the limit of no CP violation we measure the mixing parameter y_CP = -0.012+/-0.025+/-0.014 by measuring the lifetime difference between D0->K+ K- or pi+pi- and the CP neutral state, D0->K-pi+. We see no evidence for mixing.Comment: 14 pages postscript, also available through http://w4.lns.cornell.edu/public/CLNS, submitted to PRD, Rapid Communicatio

    Search for a W' boson decaying to a bottom quark and a top quark in pp collisions at sqrt(s) = 7 TeV

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    Results are presented from a search for a W' boson using a dataset corresponding to 5.0 inverse femtobarns of integrated luminosity collected during 2011 by the CMS experiment at the LHC in pp collisions at sqrt(s)=7 TeV. The W' boson is modeled as a heavy W boson, but different scenarios for the couplings to fermions are considered, involving both left-handed and right-handed chiral projections of the fermions, as well as an arbitrary mixture of the two. The search is performed in the decay channel W' to t b, leading to a final state signature with a single lepton (e, mu), missing transverse energy, and jets, at least one of which is tagged as a b-jet. A W' boson that couples to fermions with the same coupling constant as the W, but to the right-handed rather than left-handed chiral projections, is excluded for masses below 1.85 TeV at the 95% confidence level. For the first time using LHC data, constraints on the W' gauge coupling for a set of left- and right-handed coupling combinations have been placed. These results represent a significant improvement over previously published limits.Comment: Submitted to Physics Letters B. Replaced with version publishe

    Search for the standard model Higgs boson decaying into two photons in pp collisions at sqrt(s)=7 TeV

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    A search for a Higgs boson decaying into two photons is described. The analysis is performed using a dataset recorded by the CMS experiment at the LHC from pp collisions at a centre-of-mass energy of 7 TeV, which corresponds to an integrated luminosity of 4.8 inverse femtobarns. Limits are set on the cross section of the standard model Higgs boson decaying to two photons. The expected exclusion limit at 95% confidence level is between 1.4 and 2.4 times the standard model cross section in the mass range between 110 and 150 GeV. The analysis of the data excludes, at 95% confidence level, the standard model Higgs boson decaying into two photons in the mass range 128 to 132 GeV. The largest excess of events above the expected standard model background is observed for a Higgs boson mass hypothesis of 124 GeV with a local significance of 3.1 sigma. The global significance of observing an excess with a local significance greater than 3.1 sigma anywhere in the search range 110-150 GeV is estimated to be 1.8 sigma. More data are required to ascertain the origin of this excess.Comment: Submitted to Physics Letters

    Measurement of the Lambda(b) cross section and the anti-Lambda(b) to Lambda(b) ratio with Lambda(b) to J/Psi Lambda decays in pp collisions at sqrt(s) = 7 TeV

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    The Lambda(b) differential production cross section and the cross section ratio anti-Lambda(b)/Lambda(b) are measured as functions of transverse momentum pt(Lambda(b)) and rapidity abs(y(Lambda(b))) in pp collisions at sqrt(s) = 7 TeV using data collected by the CMS experiment at the LHC. The measurements are based on Lambda(b) decays reconstructed in the exclusive final state J/Psi Lambda, with the subsequent decays J/Psi to an opposite-sign muon pair and Lambda to proton pion, using a data sample corresponding to an integrated luminosity of 1.9 inverse femtobarns. The product of the cross section times the branching ratio for Lambda(b) to J/Psi Lambda versus pt(Lambda(b)) falls faster than that of b mesons. The measured value of the cross section times the branching ratio for pt(Lambda(b)) > 10 GeV and abs(y(Lambda(b))) < 2.0 is 1.06 +/- 0.06 +/- 0.12 nb, and the integrated cross section ratio for anti-Lambda(b)/Lambda(b) is 1.02 +/- 0.07 +/- 0.09, where the uncertainties are statistical and systematic, respectively.Comment: Submitted to Physics Letters
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