52,410 research outputs found

    Direct determination of the solar neutrino fluxes from solar neutrino data

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    We determine the solar neutrino fluxes from a global analysis of the solar and terrestrial neutrino data in the framework of three-neutrino mixing. Using a Bayesian approach we reconstruct the posterior probability distribution function for the eight normalization parameters of the solar neutrino fluxes plus the relevant masses and mixing, with and without imposing the luminosity constraint. This is done by means of a Markov Chain Monte Carlo employing the Metropolis-Hastings algorithm. We also describe how these results can be applied to test the predictions of the Standard Solar Models. Our results show that, at present, both models with low and high metallicity can describe the data with good statistical agreement.Comment: 24 pages, 1 table, 7 figures. Acknowledgments correcte

    Testing Contextual and Design Effects on Inter-Urban Motorists’ Responses to Time Savings

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    In the context of inter-urban motorists' route choices and the travel time savings offered by the UK's first toll motorway, a range of SP exercises tested various contextual and design effects. The design aspects relate to how the marginal benefit of time savings is influenced by the size and sign of the time saving, task complexity, presentation format, and whether the choice context is real. The contextual factors cover the impact of journey duration, attribute credibility, and where in the journey the time savings occur. The conclusions are largely credible but in some cases challenge established views and contribute significantly to understanding in this area

    Geometry of Policy Improvement

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    We investigate the geometry of optimal memoryless time independent decision making in relation to the amount of information that the acting agent has about the state of the system. We show that the expected long term reward, discounted or per time step, is maximized by policies that randomize among at most kk actions whenever at most kk world states are consistent with the agent's observation. Moreover, we show that the expected reward per time step can be studied in terms of the expected discounted reward. Our main tool is a geometric version of the policy improvement lemma, which identifies a polyhedral cone of policy changes in which the state value function increases for all states.Comment: 8 page

    Utilizing Colored Dissolved Organic Matter to Derive Dissolved Black Carbon Export by Arctic Rivers

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    Wildfires have produced black carbon (BC) since land plants emerged. Condensed aromatic compounds, a form of BC, have accumulated to become a major component of the soil carbon pool. Condensed aromatics leach from soils into rivers, where they are termed dissolved black carbon (DBC). The transport of DBC by rivers to the sea is a major term in the global carbon and BC cycles. To estimate Arctic river DBC export, 25 samples collected from the six largest Arctic rivers (Kolyma, Lena, Mackenzie, Ob’, Yenisey and Yukon) were analyzed for dissolved organic carbon (DOC), colored dissolved organic matter (CDOM), and DBC. A simple, linear regression between DOC and DBC indicated that DBC accounted for 8.9 ± 0.3% DOC exported by Arctic rivers. To improve upon this estimate, an optical proxy for DBC was developed based upon the linear correlation between DBC concentrations and CDOM light absorption coefficients at 254 nm (a254). Relatively easy to measure a254 values were determined for 410 Arctic river samples between 2004 and 2010. Each of these a254 values was converted to a DBC concentration based upon the linear correlation, providing an extended record of DBC concentration. The extended DBC record was coupled with daily discharge data from the six rivers to estimate riverine DBC loads using the LOADEST modeling program. The six rivers studied cover 53% of the pan-Arctic watershed and exported 1.5 ± 0.1 million tons of DBC per year. Scaling up to the full area of the pan-Arctic watershed, we estimate that Arctic rivers carry 2.8 ± 0.3 million tons of DBC from land to the Arctic Ocean each year. This equates to ~8% of Arctic river DOC export, slightly less than indicated by the simpler DBC vs DOC correlation-based estimate. Riverine discharge is predicted to increase in a warmer Arctic. DBC export was positively correlated with river runoff, suggesting that the export of soil BC to the Arctic Ocean is likely to increase as the Arctic warms

    Effects Of Large Predators On The Field Culture Of The Hard Clam, Mercenaria mercenaria

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    Individuals in the clam industry h ave used fences to keep the cownose ray, Rhirioptera bonasus, out of planted areas (Lewis 2 ; Burton3 ). Tiller et al. ( 1952) indicated losses due to skates in planted holding areas and stated that One man reported the loss of 600 bushels of small clams in two nights during 1948 .... Merriner and Smith4 stated that cownose ray predation is a serious problem on oyster and clam grounds in Chesapeake Bay. From these observations it is clear that such large predators could be a significant deterrent to the culture of clams from Delaware Bay southward along the Atlantic coast. The present study continues a program designed tv evaluate methods of protecting areas seeded with young Mercenaria mercenari

    Determination of Some Physical Properties of Three Groundnut Varieties

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    The determination of physical properties of some groundnut varieties is of paramount importance in the design and development of systems and machines for the shelling of groundnuts. Three varieties of groundnuts namely ICGV-SM-93523, RMP-9 and RMP- 12 were collected and some of the physical properties, such as weight, angle of repose, coefficient of friction, bulk density, size, shape and moisture content were determined.The angle of repose for the three varieties was found to range from 27.5 - 29.50 f or tire pods, 20.3 - 20.80 for the seeds and 33.7 - 36.00 for the shells. Coefficient of friction averaged 0.56 on wood and 0.41 on galvanized steel for the three varieties of groundnut pods. The moisture contents of the pods, seeds and shells were found to be 7.4%, 6.4% and 11.3% (wet basis) on the average respectively. The results also showed that groundnut pods and seeds were neither round nor spherical, but may be oblong in shape. Statistical single-factor analysis of variance (ANOVA) carried out to compare the mean values of the physical properties of the three varieties of groundnuts showed that there were no significant varietal differences at p£ 0.5 probability level. Tire implication of no significant varietal difference at p£ 0.5 is that one machine can conveniently handle the shelling operation for the three varieties of groundnuts

    GABA(A) receptor phospho-dependent modulation is regulated by phospholipase C-related inactive protein type 1, a novel protein phosphatase 1 anchoring protein

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    GABA(A) receptors are critical in controlling neuronal activity. Here, we examined the role for phospholipase C-related inactive protein type 1 (PRIP-1), which binds and inactivates protein phosphatase 1alpha (PP1alpha) in facilitating GABA(A) receptor phospho-dependent regulation using PRIP-1(-/-) mice. In wild-type animals, robust phosphorylation and functional modulation of GABA(A) receptors containing beta3 subunits by cAMP-dependent protein kinase was evident, which was diminished in PRIP-1(-/-) mice. PRIP-1(-/-) mice exhibited enhanced PP1alpha activity compared with controls. Furthermore, PRIP-1 was able to interact directly with GABA(A) receptor beta subunits, and moreover, these proteins were found to be PP1alpha substrates. Finally, phosphorylation of PRIP-1 on threonine 94 facilitated the dissociation of PP1alpha-PRIP-1 complexes, providing a local mechanism for the activation of PP1alpha. Together, these results suggest an essential role for PRIP-1 in controlling GABA(A) receptor activity via regulating subunit phosphorylation and thereby the efficacy of neuronal inhibition mediated by these receptors
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