386 research outputs found
A framework for the integrated assessment of social and economic values associated with man-made marine structures
Man-made marine structures (MMS) are increasingly prevalent in the marine environment, reflecting the growth and diversity of economic and recreational activities in both onshore and offshore settings. The presence of MMS presents opportunities and conflicts for marine planners, particularly in relation to reconciling competing stakeholder interests arising from their placement and long-term fate, including decommissioning and/or removal. This necessitates the development of an integrated framework which encapsulates the complexity of social and economic values and perceptions held by differing stakeholders. Through research conducted with MMS stakeholders in Australia, we present the first framework of this type which identifies three principal categories of socio-economic values and explores the inter-relationships between these groupings. The research further underlines the pivotal significance of rules and norms which impact across all three categories. These findings will assist planners in understanding the preferences of relevant marine stakeholders in order to enhance benefits and minimise conflicts related to MMS
Implications of partially degenerate neutrinos at a high scale in the light of KamLAND and WMAP
Electroweak radiative corrections can generate the neutrino (mass)
difference required for the large mixing angle solution (LMA) to the solar
neutrino problem if two of the neutrinos are assumed degenerate at high energy.
We test this possibility with the existing experimental knowledge of the low
energy neutrino mass and mixing parameters. We derive restrictions on ranges of
the high scale mixing matrix elements and obtain predictions for the low energy
parameters required in order to get the LMA solution of the solar neutrino
problem picked out by KamLAND. We find that in the case of standard model this
is achieved only when the (degenerate) neutrino masses lie in the range
(0.7-2) \eV which is at odds with the cosmological limit m_{\nu}<0.23 \eV
(at ) established recently using WMAP results. Thus SM radiative
corrections cannot easily generate the LMA solution in this scenario. However,
the LMA solution is possible in case of the MSSM electroweak corrections with
(almost) degenerate spectrum or with inverted mass hierarchy for limited ranges
in the high scale parameters.Comment: 15 pages, LATEX includes five postscript figure
Neutrino Masses with "Zero Sum" Condition:
It is well known that the neutrino mass matrix contains more parameters than
experimentalists can hope to measure in the foreseeable future even if we
impose CP invariance. Thus, various authors have proposed ansatzes to restrict
the form of the neutrino mass matrix further. Here we propose that ; this ``zero sum'' condition can occur in certain
class of models, such as models whose neutrino mass matrix can be expressed as
commutator of two matrices. With this condition, the absolute neutrino mass can
be obtained in terms of the mass-squared differences. When combined with the
accumulated experimental data this condition predicts two types of mass
hierarchies, with one of them characterized by eV, and the other by eV and eV. The mass ranges
predicted is just below the cosmological upper bound of 0.23 eV from recent
WMAP data and can be probed in the near future. We also point out some
implications for direct laboratory measurement of neutrino masses, and the
neutrino mass matrix.Comment: Latex 12 pages. No figures. New references adde
The development of gaze following in monolingual and bilingual infants: A multi‐laboratory study
The Impact of |Delta I|=5/2 Transitions in K-> pi pi Decays
We consider the impact of isospin violation on the analysis of K-> pi pi
decays. We scrutinize, in particular, the phenomenological role played by the
additional weak amplitude, of |Delta I|=5/2 in character, incurred by the
presence of isospin violation. We show that Watson's theorem is appropriate in
O(m_d-m_u), so that the inferred pi-pi phase shift at sqrt{s}=m_K determines
the strong phase difference between the I=0 and I=2 amplitudes in K-> pi pi
decay. We find the magnitude of the |Delta I|=5/2 amplitude thus implied by the
empirical branching ratios to be larger than expected from estimates of
isospin-violating strong and electromagnetic effects. We effect a new
determination of the octet and 27-plet coupling constants with
strong-interaction isospin violation and with electromagnetic effects, as
computed by Cirigliano, Donoghue, and Golowich, and find that we are unable to
resolve the difficulty. Exploring the role of |Delta I|=5/2 transitions in the
CP-violating observable epsilon'/epsilon, we determine that the presence of a
|Delta I|=5/2 amplitude impacts the empirical determination of omega, the ratio
of the real parts of the |Delta I|=3/2 to |Delta I|=1/2 amplitudes, and that it
generates a decrease in the estimation of epsilon'/epsilon.Comment: 29 pages, 1 ps fig, refs. added, to appear in Phys. Rev.
A New Prediction for Direct CP Violation \epsilon'/\epsilon and \Delta I = 1/2 Rule
The low energy dynamics of QCD is investigated with special attention paid to
the matching between QCD and chiral perturbation theory(ChPT), and also to some
useful algebraic chiral operator relations which survive even when we include
chiral loop corrections. It then allows us to evaluate the hadronic matrix
elements below the energy scale GeV. Based on the new
analyzes, we present a consistent prediction for both direct CP-violating
parameter and rule in the kaon decays. In
the leading approximation, the isospin amplitudes and are
found to agree well with the data, and the direct CP-violating parameter
is predicted to be large, which also confirms our early
conclusion. Its numerical value is which is no
longer sensitive to the strange quark mass due to the matching conditions.
Taking into account a simultaneous consistent analysis on the isospin
amplitudes and , the ratio is in favor of the
values .Comment: 19 pages, ReVtex, no figures, the corrected version to be published
in Phys. Rev. D . A more favorable and consistent prediction for direct CP
violation is found: epsilon'(prime) /epsilon = (20 \pm 9) x 10^-4, here the
contributions from finite meson masses and new isospin symmetry breaking
effects have been included. The uncertainties from QCD (or low energy) scale
have been considered. More references are adde
A causal roadmap for generating high-quality real-world evidence
Increasing emphasis on the use of real-world evidence (RWE) to support clinical policy and regulatory decision-making has led to a proliferation of guidance, advice, and frameworks from regulatory agencies, academia, professional societies, and industry. A broad spectrum of studies use real-world data (RWD) to produce RWE, ranging from randomized trials with outcomes assessed using RWD to fully observational studies. Yet, many proposals for generating RWE lack sufficient detail, and many analyses of RWD suffer from implausible assumptions, other methodological flaws, or inappropriate interpretations. The Causal Roadmap is an explicit, itemized, iterative process that guides investigators to prespecify study design and analysis plans; it addresses a wide range of guidance within a single framework. By supporting the transparent evaluation of causal assumptions and facilitating objective comparisons of design and analysis choices based on prespecified criteria, the Roadmap can help investigators to evaluate the quality of evidence that a given study is likely to produce, specify a study to generate high-quality RWE, and communicate effectively with regulatory agencies and other stakeholders. This paper aims to disseminate and extend the Causal Roadmap framework for use by clinical and translational researchers; three companion papers demonstrate applications of the Causal Roadmap for specific use cases
Measurement of the View the tt production cross-section using eμ events with b-tagged jets in pp collisions at √s = 13 TeV with the ATLAS detector
This paper describes a measurement of the inclusive top quark pair production cross-section (σtt¯) with a data sample of 3.2 fb−1 of proton–proton collisions at a centre-of-mass energy of √s = 13 TeV, collected in 2015 by the ATLAS detector at the LHC. This measurement uses events with an opposite-charge electron–muon pair in the final state. Jets containing b-quarks are tagged using an algorithm based on track impact parameters and reconstructed secondary vertices. The numbers of events with exactly one and exactly two b-tagged jets are counted and used to determine simultaneously σtt¯ and the efficiency to reconstruct and b-tag a jet from a top quark decay, thereby minimising the associated systematic uncertainties. The cross-section is measured to be:
σtt¯ = 818 ± 8 (stat) ± 27 (syst) ± 19 (lumi) ± 12 (beam) pb,
where the four uncertainties arise from data statistics, experimental and theoretical systematic effects, the integrated luminosity and the LHC beam energy, giving a total relative uncertainty of 4.4%. The result is consistent with theoretical QCD calculations at next-to-next-to-leading order. A fiducial measurement corresponding to the experimental acceptance of the leptons is also presented
Search for strong gravity in multijet final states produced in pp collisions at √s=13 TeV using the ATLAS detector at the LHC
A search is conducted for new physics in multijet final states using 3.6 inverse femtobarns of data from proton-proton collisions at √s = 13TeV taken at the CERN Large Hadron Collider with the ATLAS detector. Events are selected containing at least three jets with scalar sum of jet transverse momenta (HT) greater than 1TeV. No excess is seen at large HT and limits are presented on new physics: models which produce final states containing at least three jets and having cross sections larger than 1.6 fb with HT > 5.8 TeV are excluded. Limits are also given in terms of new physics models of strong gravity that hypothesize additional space-time dimensions
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