134 research outputs found

    Evolution and progressive geomorphic manifestation of surface faulting: A comparison of the Wairau and Awatere faults, South Island, New Zealand

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    Field mapping and lidar analysis of surface faulting patterns expressed in flights of geologically similar fluvial terraces at the well-known Branch River and Saxton River sites along the Wairau (Alpine) and Awatere strike-slip faults, South Island, New Zealand, reveal that fault-related deformation patterns expressed in the topography at these sites are markedly less structurally complex along the higher-displacement (hundreds of kilometers), structurally mature Wairau fault than along the Awatere fault (∼13–20 km total slip). These differences, which are generally representative of the surface traces of these faults, provide direct evidence that surface faulting becomes structurally simpler with increasing cumulative fault offset. We also examine the degree to which off-fault deformation (OFD) is expressed in the landscape at the Saxton River site along the less structurally mature Awatere fault. Significantly greater amounts of OFD are discernible as a wide damage zone (∼460 m fault-perpendicular width) in older (ca. 15 ka), more-displaced (64–74 m) fluvial terraces than in younger (ca. 1–7 ka), less-displaced (<55 m) terraces; no OFD is discernible in the lidar data on the least-displaced (<35 m) terraces. From this, we infer that OFD becomes progressively more geomorphically apparent with accumulating displacement. These observations imply that (1) the processes that accommodate OFD are active during each earthquake, but may not be evident in deposits that have experienced relatively small displacements; (2) structures accommodating OFD will become progressively geomorphically clearer with increasing displacement; (3) geomorphic measurements of overall fault zone width taken in deposits that have experienced small displacements will be underestimates; and (4) fault slip rates based on geomorphic surface offsets will be underestimates for immature faults if based solely on measurements along the high-strain fault core

    Stable isotope food-web analysis and mercury biomagnification in polar bears ( Ursus maritimus )

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    Mercury (Hg) biomagnification occurs in many ecosystems, resulting in a greater potential for toxicological effects in higher-level trophic feeders. However, Hg transport pathways through different food-web channels are not well known, particularly in high-latitude systems affected by the atmospheric Hg deposition associated with snow and ice. Here, we report on stable carbon and nitrogen isotope ratios, and Hg concentrations, determined for 26, late 19th and early 20th century, polar bear ( Ursus maritimus ) hair specimens, collected from catalogued museum collections. These data elucidate relationships between the high-latitude marine food-web structure and Hg concentrations in polar bears. The carbon isotope compositions of polar bear hairs suggest that polar bears derive nutrition from coupled food-web channels, based in pelagic and sympagic primary producers, whereas the nitrogen isotope compositions indicate that polar bears occupy > fourth-level trophic positions. Our results show a positive correlation between polar bear hair Hg concentrations and δ 15 N. Interpretation of the stable isotope data in combination with Hg concentrations tentatively suggests that polar bears participating in predominantly pelagic food webs exhibit higher mercury concentrations than polar bears participating in predominantly sympagic food webs.Peer Reviewedhttp://deepblue.lib.umich.edu/bitstream/2027.42/73930/1/j.1751-8369.2009.00114.x.pd

    Measurement of the CP-violating phase β in B0→J/ψπ+π− decays and limits on penguin effects

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    18 pages, 6 figures - See paper for full list of authorsInternational audienceTime-dependent CP violation is measured in the B0→J/ψπ+π− channel for each π+π− resonant final state using data collected with an integrated luminosity of 3.0 fb−1 in pp collisions using the LHCb detector. The final state with the largest rate, J/ψρ0(770), is used to measure the CP-violating angle 2βeff to be (41.7±9.6+2.8−6.3)∘. This result can be used to limit the size of penguin amplitude contributions to CP violation measurements in, for example, B0s→J/ψϕ decays. Assuming approximate SU(3) flavour symmetry and neglecting higher order diagrams, the shift in the CP-violating phase ϕs is limited to be within the interval [−1.05∘, +1.18∘] at 95% confidence level. Changes to the limit due to SU(3) symmetry breaking effects are also discussed

    Determination of gamma and -2beta_s from charmless two-body decays of beauty mesons

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    See paper for full list of authorsInternational audienceUsing the latest LHCb measurements of time-dependent CP violation in the B^0_s -> K^+K^- decay, a U-spin relation between the decay amplitudes of B^0_s -> K^+K^- and B^0 -> \pi^+\pi^- decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B^0_s mixing phase -2\beta_s. Results from an extended approach, which uses additional inputs on B^0 -> \pi^0\pi^0 and B^+ -> \pi^+\pi^0 decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value \gamma = ( 63.5 +7.2 -6.7 ) degrees modulo 180 degrees is determined. In an alternative analysis, the value -2\beta_s = -0.12 +0.14 -0.16 rad is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included

    Measurement of the lifetime of the B+c meson using the B+c→J/ψπ+ decay mode

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    See paper for full list of authors - 19 pages, 3 figuresInternational audienceThe difference in total widths between the B+c and B+ mesons is measured using 3.0fb−1 of data collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton-proton collisions at the LHC. Through the study of the time evolution of B+c→J/ψπ+ and B+→J/ψK+ decays, the width difference is measured to beΔΓ≡ΓB+c−ΓB+=4.46±0.14±0.07mm−1c,where the first uncertainty is statistical and the second systematic. The known lifetime of the B+ meson is used to convert this to a precise measurement of the B+c lifetime,τB+c=513.4±11.0±5.7fs,where the first uncertainty is statistical and the second systematic

    Study of the rare B0s and B0 decays into the π+π−μ+μ− final state

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    See paper for full list of authors - Submitted to Phys. Lett. BInternational audienceA search for the rare decays B0s→π+π−μ+μ− and B0→π+π−μ+μ− is performed in a data set corresponding to an integrated luminosity of 3.0 fb−1 collected by the LHCb detector in proton-proton collisions at centre-of-mass energies of 7 and 8 TeV. Decay candidates with pion pairs that have invariant mass in the range 0.5-1.3 GeV/c2 and with muon pairs that do not originate from a resonance are considered. The first observation of the decay B0s→π+π−μ+μ− and the first evidence of the decay B0→π+π−μ+μ− are obtained and the branching fractions are measured to be B(B0s→π+π−μ+μ−)=(8.6±1.5(stat)±0.7(syst)±0.7(norm))×10−8 and B(B0→π+π−μ+μ−)=(2.11±0.51(stat)±0.15(syst)±0.16(norm))×10−8, where the third uncertainty is due to the branching fraction of the decay B0→J/ψ(→μ+μ−)K∗(890)0(→K+π−), used as a normalisation

    WHO global research priorities for antimicrobial resistance in human health

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    The WHO research agenda for antimicrobial resistance (AMR) in human health has identified 40 research priorities to be addressed by the year 2030. These priorities focus on bacterial and fungal pathogens of crucial importance in addressing AMR, including drug-resistant pathogens causing tuberculosis. These research priorities encompass the entire people-centred journey, covering prevention, diagnosis, and treatment of antimicrobial-resistant infections, in addition to addressing the overarching knowledge gaps in AMR epidemiology, burden and drivers, policies and regulations, and awareness and education. The research priorities were identified through a multistage process, starting with a comprehensive scoping review of knowledge gaps, with expert inputs gathered through a survey and open call. The priority setting involved a rigorous modified Child Health and Nutrition Research Initiative approach, ensuring global representation and applicability of the findings. The ultimate goal of this research agenda is to encourage research and investment in the generation of evidence to better understand AMR dynamics and facilitate policy translation for reducing the burden and consequences of AMR

    Determination of gamma and-2 beta(s) from charmless two-body decays of beauty mesons

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    Using the latest LHCb measurements of time-dependent CP violation in the B^0_s -> K^+K^- decay, a U-spin relation between the decay amplitudes of B^0_s -> K^+K^- and B^0 -> \pi^+\pi^- decay processes allows constraints to be placed on the angle gamma of the unitarity triangle and on the B^0_s mixing phase -2\beta_s. Results from an extended approach, which uses additional inputs on B^0 -> \pi^0\pi^0 and B^+ -> \pi^+\pi^0 decays from other experiments and exploits isospin symmetry, are also presented. The dependence of the results on the maximum allowed amount of U-spin breaking is studied. At 68% probability, the value \gamma = ( 63.5 +7.2 -6.7 ) degrees modulo 180 degrees is determined. In an alternative analysis, the value -2\beta_s = -0.12 +0.14 -0.16 rad is found. In both measurements, the uncertainties due to U-spin breaking effects up to 50% are included.Comment: updated to v2 with minor changes after journal revie

    Measurement of the lifetime of the Bc+B_c^+ meson using the Bc+J/ψπ+B_c^+\rightarrow J/\psi\pi^+ decay mode

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    The difference in total widths between the Bc+B_c^+ and B+B^+ mesons is measured using 3.0fb1^{-1} of data collected by the LHCb experiment in 7 and 8 TeV centre-of-mass energy proton-proton collisions at the LHC. Through the study of the time evolution of Bc+J/ψπ+B_c^+ \rightarrow J/\psi \pi^+ and B+J/ψK+B^+\rightarrow J/\psi K^+ decays, the width difference is measured to be ΔΓΓBc+ΓB+=4.46±0.14±0.07mm1c, \Delta\Gamma \equiv \Gamma_{B_c^+} - \Gamma_{B^+} = 4.46 \pm 0.14 \pm 0.07mm^{-1}c, where the first uncertainty is statistical and the second systematic. The known lifetime of the B+B^+ meson is used to convert this to a precise measurement of the Bc+B_c^+ lifetime, τBc+=513.4±11.0±5.7fs,\tau_{B_c^+} = 513.4 \pm 11.0 \pm 5.7fs, where the first uncertainty is statistical and the second systematic.Comment: 19 pagers, 3 figure

    Search for CP violation in D±KS0K±D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm} and Ds±KS0π±D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} π^{\pm} decays

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    A search for \CP violation in Cabibbo-suppressed D±KS0K±D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm} and Ds±KS0π±D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm} decays is performed using pppp collision data, corresponding to an integrated luminosity of 3~fb1^{-1}, recorded by the LHCb experiment. The individual CPCP-violating asymmetries are measured to be \begin{eqnarray*} \mathcal{A}_{CP}^{D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm}} & = & (+0.03 \pm 0.17 \pm 0.14) \% \mathcal{A}_{CP}^{D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm}} & = & (+0.38 \pm 0.46 \pm 0.17) \%, \end{eqnarray*} assuming that CPCP violation in the Cabibbo-favoured decays is negligible. A combination of the measured asymmetries for the four decay modes D(s)±KS0K±D^{\pm}_{(s)}\rightarrow K^0_{\mathrm{S}} K^{\pm} and D(s)±KS0π±D^{\pm}_{(s)}\rightarrow K^0_{\mathrm{S}} \pi^{\pm} gives the sum ACPD±KS0K±+ACPDs±KS0π±=(+0.41±0.49±0.26)%. \mathcal{A}_{CP}^{D^{\pm}\rightarrow K^0_{\mathrm{S}} K^{\pm}} + \mathcal{A}_{CP}^{D^{\pm}_{s}\rightarrow K^0_{\mathrm{S}} \pi^{\pm}} = (+0.41 \pm 0.49 \pm 0.26) \%. In all cases, the first uncertainties are statistical and the second systematic. The results represent the most precise measurements of these asymmetries to date and show no evidence for CP violation
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