6,153 research outputs found

    Late quaternary time series of Arabian Sea productivity: Global and regional signals

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    Modern annual floral and faunal production in the northwest Arabian Sea derives primarily from upwelling induced by strong southwest winds during June, July, and August. Indian Ocean summer monsoon winds are, in turn, driven by differential heating between the Asian continent and the Indian ocean to the south. This differential heating produces a strong pressure gradient resulting in southwest monsoon winds and both coastal and divergent upwelling off the Arabian Peninsula. Over geologic time scales (10(exp 4) to 10(exp 6) years), monsoon wind strength is sensitive to changes in boundary conditions which influence this pressure gradient. Important boundary conditions include the seasonal distribution of solar radiation, global ice volume, Indian Ocean sea surface temperature, and the elevation and albedo of the Asian continent. To the extent that these factors influence monsoon wind strength, they also influence upwelling and productivity. In addition, however, productivity associated with upwelling can be decoupled from the strength of the summer monsoon winds via ocean mechanisms which serve to inhibit or enhance the nutrient supply in the intermediate waters of the Indian Ocean, the source for upwelled waters in the Arabian Sea. To differentiate productivity associated with wind-induced upwelling from that associated with other components of the system such as nutrient sequestering in glacial-age deep waters, we employ a strategy which monitors independent components of the oceanic and atmospheric subsystems. Using sediment records from the Owen Ridge, northwest Arabian Sea, we monitor the strength of upwelling and productivity using two independent indicators, percent G. bulloides and opal accumulation. We monitor the strength of southwest monsoon winds by measuring the grain-size of lithogenic dust particles blown into the Arabian Sea from the surrounding deserts of the Somali and Arabian Peninsulas. Our current hypothesis is that the variability associated with the 41 kyr power in the G. bulloides and opal accumulation records derive from nutrient availability in the intermediate waters which are upwelled via monsoon winds. This hypothesis is testable by comparison with Cd records of intermediate and deep waters of the Atlantic and Indian Ocean

    Monitoring food marketing to children: A joint Nordic monitoring protocol for marketing of foods and beverages high in fat, salt and sugar (HFSS) towards children and young people

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    The protocol describes methods for how to monitor marketing of foods and beverages high in fat, salt and sugar towards children and young people at a given time as cross-sectional studies, as well as allowing for monitoring of trends. The data provided could also be used for evaluation purposes, for instance providing relevant data for evaluating regulation practices and schemes in the respective countries; to study advertising and marketing practices, contents and forms over time. In addition to being a tool for monitoring purposes within each country, the protocol will also enable comparisons between the Nordic countries by establishing a joint understanding on how each marketing channel should be monitored. The protocol has been developed as a Nordic project between representatives and experts from Iceland, Finland, Sweden, Denmark and Norway together with international experts

    Averages of b-hadron Properties at the End of 2005

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    This article reports world averages for measurements on b-hadron properties obtained by the Heavy Flavor Averaging Group (HFAG) using the available results as of at the end of 2005. In the averaging, the input parameters used in the various analyses are adjusted (rescaled) to common values, and all known correlations are taken into account. The averages include lifetimes, neutral meson mixing parameters, parameters of semileptonic decays, branching fractions of B meson decays to final states with open charm, charmonium and no charm, and measurements related to CP asymmetries

    The Atlantic Ocean at the last glacial maximum: 1. Objective mapping of the GLAMAP sea-surface conditions

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    Recent efforts of the German paleoceanographic community have resulted in a unique data set of reconstructed sea-surface temperature for the Atlantic Ocean during the Last Glacial Maximum, plus estimates for the extents of glacial sea ice. Unlike prior attempts, the contributing research groups based their data on a common definition of the Last Glacial Maximum chronozone and used the same modern reference data for calibrating the different transfer techniques. Furthermore, the number of processed sediment cores was vastly increased. Thus the new data is a significant advance not only with respect to quality, but also to quantity. We integrate these new data and provide monthly data sets of global sea-surface temperature and ice cover, objectively interpolated onto a regular 1°x1° grid, suitable for forcing or validating numerical ocean and atmosphere models. This set is compared to an existing subjective interpolation of the same base data, in part by employing an ocean circulation model. For the latter purpose, we reconstruct sea surface salinity from the new temperature data and the available oxygen isotope measurements

    Sea surface temperature changes in the southern California borderlands during the last glacial-interglacial cycle

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    A variety of evidence suggests that average sea surface temperatures (SSTs) during the last glacial maximum in the California Borderlands region were significantly colder than during the Holocene. Planktonic foraminiferal δ18O evidence and average SST estimates derived by the modern analog technique indicate that temperatures were 6°-10°C cooler during the last glacial relative to the present. The glacial plankton assemblage is dominated by the planktonic foraminifer Neogloboquadrina pachyderma (sinistral coiling) and the coccolith Coccolithus pelagicus, both of which are currently restricted to subpolar regions of the North Pacific. The glacial-interglacial average SST change determined in this study is considerably larger than the 2°C change estimated by Climate: Long-Range Investigation, Mapping, and Prediction (CLIMAP) [1981]. We propose that a strengthened California Current flow was associated with the advance of subpolar surface waters into the Borderlands region during the last glacial

    Observation of the Dynamic Beta Effect at CESR with CLEO

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    Using the silicon strip detector of the CLEO experiment operating at the Cornell Electron-positron Storage Ring (CESR), we have observed that the horizontal size of the luminous region decreases in the presence of the beam-beam interaction from what is expected without the beam-beam interaction. The dependence on the bunch current agrees with the prediction of the dynamic beta effect. This is the first direct observation of the effect.Comment: 9 page uuencoded postscript file, postscritp file also available through http://w4.lns.cornell.edu/public/CLNS, submitted to Phys. Rev.

    Measurement of CP Asymmetries and Branching Fractions in Charmless Two-Body B-Meson Decays to Pions and Kaons

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    We present improved measurements of CP-violation parameters in the decays B0π+πB^0 \to \pi^+ \pi^-, B0K+πB^0 \to K^+ \pi^-, and B0π0π0B^0 \to \pi^0 \pi^0, and of the branching fractions for B0π0π0B^0 \to \pi^0 \pi^0 and B0K0π0B^0 \to K^0 \pi^0. The results are obtained with the full data set collected at the Υ(4S)\Upsilon(4S) resonance by the BABAR experiment at the PEP-II asymmetric-energy BB factory at the SLAC National Accelerator Laboratory, corresponding to 467±5467 \pm 5 million BBˉB\bar B pairs. We find the CP-violation parameter values and branching fractions Sπ+π=0.68±0.10±0.03,Cπ+π=0.25±0.08±0.02,AKπ+=0.107±0.0160.004+0.006,Cπ0π0=0.43±0.26±0.05,Br(B0π0π0)=(1.83±0.21±0.13)×106,Br(B0K0π0)=(10.1±0.6±0.4)×106, S_{\pi^+\pi^-} = -0.68 \pm 0.10 \pm 0.03, C_{\pi^+\pi^-} = -0.25 \pm 0.08 \pm 0.02, A_{K^-\pi^+} = -0.107 \pm 0.016 ^{+0.006}_{-0.004}, C_{\pi^0\pi^0} = -0.43 \pm 0.26 \pm 0.05, Br(B^0 \to \pi^0 \pi^0) = (1.83 \pm 0.21 \pm 0.13) \times 10^{-6}, Br(B^0 \to K^0 \pi^0) = (10.1 \pm 0.6 \pm 0.4) \times 10^{-6}, where in each case, the first uncertainties are statistical and the second are systematic. We observe CP violation with a significance of 6.7 standard deviations for B0π+πB^0 \to\pi^+\pi^- and 6.1 standard deviations for B0K+πB^0 \to K^+ \pi^-, including systematic uncertainties. Constraints on the Unitarity Triangle angle α\alpha are determined from the isospin relations among the BππB \to \pi\pi rates and asymmetries. Considering only the solution preferred by the Standard Model, we find α\alpha to be in the range [71,109][71^\circ,109^\circ] at the 68% confidence level.Comment: 18 pages, 11 postscript figures, submitted to Phys. Rev.
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