1,358 research outputs found

    Joint effects of storm surge and sea-level rise on US Coasts: new economic estimates of impacts, adaptation, and benefits of mitigation policy

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    Recent literature, the US Global Change Research Program’s National Climate Assessment, and recent events, such as Hurricane Sandy, highlight the need to take better account of both storm surge and sea-level rise (SLR) in assessing coastal risks of climate change. This study combines three models—a tropical cyclone simulation model; a storm surge model; and a model for economic impact and adaptation—to estimate the joint effects of storm surge and SLR for the US coast through 2100. The model is tested using multiple SLR scenarios, including those incorporating estimates of dynamic ice-sheet melting, two global greenhouse gas (GHG) mitigation policy scenarios, and multiple general circulation model climate sensitivities. The results illustrate that a large area of coastal land and property is at risk of damage from storm surge today; that land area and economic value at risk expands over time as seas rise and as storms become more intense; that adaptation is a cost-effective response to this risk, but residual impacts remain after adaptation measures are in place; that incorporating site-specific episodic storm surge increases national damage estimates by a factor of two relative to SLR-only estimates, with greater impact on the East and Gulf coasts; and that mitigation of GHGs contributes to significant lessening of damages. For a mid-range climate-sensitivity scenario that incorporates dynamic ice sheet melting, the approach yields national estimates of the impacts of storm surge and SLR of 990billionthrough2100(netofadaptation,cumulativeundiscounted2005990 billion through 2100 (net of adaptation, cumulative undiscounted 2005); GHG mitigation policy reduces the impacts of the mid-range climate-sensitivity estimates by 84to84 to 100 billion.United States. Environmental Protection Agency. Climate Change Division (Contract EP-D-09-054)United States. Environmental Protection Agency. Climate Change Division (Contract EP-BPA-12-H-0024

    Barium abundance in red giants of NGC 6752. Non-local thermodynamic equilibrium and three-dimensional effects

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    (Abridged) Aims: We study the effects related to departures from non-local thermodynamic equilibrium (NLTE) and homogeneity in the atmospheres of red giant stars in Galactic globular cluster NGC 6752, to assess their influence on the formation of Ba II lines. Methods: One-dimensional (1D) local thermodynamic equilibrium (LTE) and 1D NLTE barium abundances were derived using classical 1D ATLAS stellar model atmospheres. The three-dimensional (3D) LTE abundances were obtained for 8 red giants on the lower RGB, by adjusting their 1D LTE abundances using 3D-1D abundance corrections, i.e., the differences between the abundances obtained from the same spectral line using the 3D hydrodynamical (CO5BOLD) and classical 1D (LHD) stellar model atmospheres. Results: The mean 1D barium-to-iron abundance ratios derived for 20 giants are _{1D NLTE} = 0.05 \pm0.06 (stat.) \pm0.08 (sys.). The 3D-1D abundance correction obtained for 8 giants is small (~+0.05 dex), thus leads to only minor adjustment when applied to the mean 1D NLTE barium-to-iron abundance ratio for the 20 giants, _{3D+NLTE} = 0.10 \pm0.06(stat.) \pm0.10(sys.). The intrinsic abundance spread between the individual cluster stars is small and can be explained in terms of uncertainties in the abundance determinations. Conclusions: Deviations from LTE play an important role in the formation of barium lines in the atmospheres of red giants studied here. The role of 3D hydrodynamical effects should not be dismissed either, even if the obtained 3D-1D abundance corrections are small. This result is a consequence of subtle fine-tuning of individual contributions from horizontal temperature fluctuations and differences between the average temperature profiles in the 3D and 1D model atmospheres: owing to the comparable size and opposite sign, their contributions nearly cancel each other.Comment: Minor typos corrected. Accepted for publication in A&A (9 pages, 3 figures, 6 tables

    Author Correction: Genome-Guided Phylo-Transcriptomic Methods and the Nuclear Phylogenetic Tree of the Paniceae Grasses

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    The original version of this Article contained an error in the title of the paper, where the word “Phylogenetic” was incorrectly given as “Phylogentic”. This has now been corrected in the PDF and HTML versions of the Article, and in the accompanying Supplementary Information file

    The Chemical Composition and Age of the Metal-Poor Halo Star BD +17^\circ 3248

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    We have combined new high-resolution spectra obtained with the Hubble Space Telescope (HST) and ground-based facilities to make a comprehensive new abundance analysis of the metal-poor, halo star BD +17^\circ 3248. We have detected the third r-process peak elements osmium, platinum, and (for the first time in a metal-poor star) gold, elements whose abundances can only be reliably determined using HST. Our observations illustrate a pattern seen in other similar halo stars with the abundances of the heavier neutron-capture elements, including the third r-process peak elements, consistent with a scaled solar system r-process distribution. The abundances of the lighter neutron-capture elements, including germanium and silver, fall below that same scaled solar r-process curve, a result similar to that seen in the ultra-metal-poor star CS 22892--052. A single site with two regimes or sets of conditions, or perhaps two different sites for the lighter and heavier neutron-capture elements, might explain the abundance pattern seen in this star. In addition we have derived a reliable abundance for the radioactive element thorium. We tentatively identify U II at 3859 A in the spectrum of BD +17^\circ 3248, which makes this the second detection of uranium in a very metal-poor halo star. Our combined observations cover the widest range in proton number (from germanium to uranium) thus far of neutron-capture elements in metal-poor Galactic halo stars. Employing the thorium and uranium abundances in comparison with each other and with several stable elements, we determine an average cosmochronological age for BD +17^\circ 3248 of 13.8 +/- 4 Gyr, consistent with that found for other similar metal-poor halo stars.Comment: 58 pages, 4 tables, 11 figures; To appear in ApJ Typo correcte

    MyD88 signaling inhibits protective immunity to the gastrointestinal helminth parasite heligmosomoides polygyrus

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    Helminth parasites remain one of the most common causes of infections worldwide, yet little is still known about the immune signaling pathways that control their expulsion. C57BL/6 mice are chronically susceptible to infection with the gastrointestinal helminth parasite Heligmosomoides polygyrus. In this article, we report that C57BL/6 mice lacking the adapter protein MyD88, which mediates signaling by TLRs and IL-1 family members, showed enhanced immunity to H. polygyrus infection. Alongside increased parasite expulsion, MyD88-deficient mice showed heightened IL-4 and IL-17A production from mesenteric lymph node CD4+ cells. In addition, MyD88-/- mice developed substantial numbers of intestinal granulomas around the site of infection, which were not seen in MyD88-sufficient C57BL/6 mice, nor when signaling through the adapter protein TRIF (TIR domain-containing adapter-inducing IFN-ÎČ adapter protein) was also ablated. Mice deficient solely in TLR2, TLR4, TLR5, or TLR9 did not show enhanced parasite expulsion, suggesting that these TLRs signal redundantly to maintain H. polygyrus susceptibility in wild-type mice. To further investigate signaling pathways that are MyD88 dependent, we infected IL-1R1-/- mice with H. polygyrus. This genotype displayed heightened granuloma numbers compared with wild-type mice, but without increased parasite expulsion. Thus, the IL-1R-MyD88 pathway is implicated in inhibiting granuloma formation; however, protective immunity in MyD88-deficient mice appears to be granuloma independent. Like IL-1R1-/- and MyD88-/- mice, animals lacking signaling through the type 1 IFN receptor (i.e., IFNAR1-/-) also developed intestinal granulomas. Hence, IL-1R1, MyD88, and type 1 IFN receptor signaling may provide pathways to impede granuloma formation in vivo, but additional MyD88-mediated signals are associated with inhibition of protective immunity in susceptible C57BL/6 mice

    Bose-Einstein Correlations of Three Charged Pions in Hadronic Z^0 Decays

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    Bose-Einstein Correlations (BEC) of three identical charged pions were studied in 4 x 10^6 hadronic Z^0 decays recorded with the OPAL detector at LEP. The genuine three-pion correlations, corrected for the Coulomb effect, were separated from the known two-pion correlations by a new subtraction procedure. A significant genuine three-pion BEC enhancement near threshold was observed having an emitter source radius of r_3 = 0.580 +/- 0.004 (stat.) +/- 0.029 (syst.) fm and a strength of \lambda_3 = 0.504 +/- 0.010 (stat.) +/- 0.041 (syst.). The Coulomb correction was found to increase the \lambda_3 value by \~9% and to reduce r_3 by ~6%. The measured \lambda_3 corresponds to a value of 0.707 +/- 0.014 (stat.) +/- 0.078 (syst.) when one takes into account the three-pion sample purity. A relation between the two-pion and the three-pion source parameters is discussed.Comment: 19 pages, LaTeX, 5 eps figures included, accepted by Eur. Phys. J.

    How Common is Common Human Reason?:The Plurality of Moral Perspectives and Kant’s Ethics

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    In his practical philosophy, Kant aims to systematize and ground a conception of morality that every human being already in some form is supposedly committed to in virtue of her common human reason. While Kantians especially in the last few years have explicitly acknowledged the central role of common human reason for a correct understanding of Kant’s ethics, there has been very little detailed critical discussion of the very notion of a common human reason as Kant envisages it. Sticker critically discusses in what ways Kant is committed to the notion that there are certain rational insights and rational capacities that all humans share, and thus investigates critically how Kant thinks moral normativity appears to the common human being, the rational agent who did not enjoy special education or philosophical training
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