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541.
Uncertainty, scepticism and attitudes towards climate change: biased assimilation and attitude polarisation 总被引:1,自引:1,他引:0
‘Scepticism’ in public attitudes towards climate change is seen as a significant barrier to public engagement. In an experimental study, we measured participants’ scepticism about climate change before and after reading two newspaper editorials that made opposing claims about the reality and seriousness of climate change (designed to generate uncertainty). A well-established social psychological finding is that people with opposing attitudes often assimilate evidence in a way that is biased towards their existing attitudinal position, which may lead to attitude polarisation. We found that people who were less sceptical about climate change evaluated the convincingness and reliability of the editorials in a markedly different way to people who were more sceptical about climate change, demonstrating biased assimilation of the information. In both groups, attitudes towards climate change became significantly more sceptical after reading the editorials, but we observed no evidence of attitude polarisation—that is, the attitudes of these two groups did not diverge. The results are the first application of the well-established assimilation and polarisation paradigm to attitudes about climate change, with important implications for anticipating how uncertainty—in the form of conflicting information—may impact on public engagement with climate change. 相似文献
542.
Aqueous calcium (Ca) concentrations are currently decreasing in many softwater lakes on the Boreal Shield. As the onset of these declines often pre-date direct monitoring programs, indirect techniques are required to examine the impacts of reduced Ca availability on aquatic communities with relatively high Ca demands such as the Cladocera (Class: Branchiopoda). Among the Cladocera, the family Daphniidae has been identified as a taxonomic group potentially useful for inferring past Ca concentrations due to their high Ca demands and preservation in lake sediments. Here, we use a ??top/bottom?? paleolimnological analysis to compare present-day cladoceran communities preserved in the surface sediments of 36 softwater lakes in south-central Ontario, Canada, which are potentially vulnerable to Ca decline (i.e. small headwater systems with present-day lakewater [Ca]?<?3?mg?L?1), with the communities present in lake sediments deposited prior to the onset of regional acid deposition. To distinguish the potential impacts of lake acidification from those of Ca availability (as Ca and pH trends are strongly correlated in this region), the study lakes were chosen to be evenly distributed about a present-day lakewater pH of 6 and Ca concentration of 1.5?mg?L?1 (threshold values). Despite the importance of pH as an explanatory variable for the present-day assemblages, a comparison of the sedimentary remains from the two time periods indicate there have been large declines since pre-industrial times in the relative abundances of Ca-rich Daphnia spp. (particularly of the Daphnia longispina species complex), regardless of present-day pH, accompanied by increases in the Ca-poor species Holopedium glacialis. These observations suggest that recent declines in Ca concentration may have already fallen below baseline conditions, with marked implications for ecosystem function due to the differential responses among cladoceran taxa. 相似文献
543.
The tectonically and cryovolcanically resurfaced terrains of Ganymede attest to the satellite's turbulent geologic history. Yet, the ultimate cause of its geologic violence remains unknown. One plausible scenario suggests that the Galilean satellites passed through one or more Laplace-like resonances before evolving into the current Laplace resonance. Passage through such a resonance can excite Ganymede's eccentricity, leading to tidal dissipation within the ice shell. To evaluate the effects of resonance passage on Ganymede's thermal history we model the coupled orbital-thermal evolution of Ganymede both with and without passage through a Laplace-like resonance. In the absence of tidal dissipation, radiogenic heating alone is capable of creating large internal oceans within Ganymede if the ice grain size is 1 mm or greater. For larger grain sizes, oceans will exist into the present epoch. The inclusion of tidal dissipation significantly alters Ganymede's thermal history, and for some parameters (e.g. ice grain size, tidal Q of Jupiter) a thin ice shell (5 to 20 km) can be maintained throughout the period of resonance passage. The pulse of tidal heating that accompanies Laplace-like resonance capture can cause up to 2.5% volumetric expansion of the satellite and contemporaneous formation of near surface partial melt. The presence of a thin ice shell and high satellite orbital eccentricity would generate moderate diurnal tidal stresses in Ganymede's ice shell. Larger stresses result if the ice shell rotates non-synchronously. The combined effects of satellite expansion, its associated tensile stress, rapid formation of near surface partial melt, and tidal stress due to an eccentric orbit may be responsible for creating Ganymede's unique surface features. 相似文献
544.
Martin Sahlén Pedro T. P. Viana rew R. Liddle A. Kathy Romer Michael Davidson Mark Hosmer Ed Lloyd-Davies Kivanc Sabirli Chris A. Collins Peter E. Freeman Matt Hilton Ben Hoyle Scott T. Kay Robert G. Mann Nicola Mehrtens Christopher J. Miller Robert C. Nichol S. Adam Stanford Michael J. West † 《Monthly notices of the Royal Astronomical Society》2009,397(2):577-607
We forecast the constraints on the values of σ8 , Ωm and cluster scaling-relation parameters which we expect to obtain from the XMM Cluster Survey (XCS). We assume a flat Λ cold dark matter Universe and perform a Monte Carlo Markov Chain analysis of the evolution of the number density of galaxy clusters that takes into account a detailed simulated selection function. Comparing our current observed number of clusters shows good agreement with predictions. We determine the expected degradation of the constraints as a result of self-calibrating the luminosity–temperature relation (with scatter), including temperature measurement errors, and relying on photometric methods for the estimation of galaxy cluster redshifts. We examine the effects of systematic errors in scaling relation and measurement error assumptions. Using only ( T , z ) self-calibration, we expect to measure Ωm to ±0.03 (and ΩΛ to the same accuracy assuming flatness), and σ8 to ±0.05, also constraining the normalization and slope of the luminosity–temperature relation to ±6 and ±13 per cent (at 1σ), respectively, in the process. Self-calibration fails to jointly constrain the scatter and redshift evolution of the luminosity–temperature relation significantly. Additional archival and/or follow-up data will improve on this. We do not expect measurement errors or imperfect knowledge of their distribution to degrade constraints significantly. Scaling-relation systematics can easily lead to cosmological constraints 2σ or more away from the fiducial model. Our treatment is the first exact treatment to this level of detail, and introduces a new 'smoothed ML' (Maximum Likelihood) estimate of expected constraints. 相似文献
545.
The temperature of the atomic matter in the Universe is held to that of the cosmic background radiation until decoupling at z ∼ 100 . After this, it cools faster than the radiation [ ∝ (1 + z )2 rather than (1 + z ) ] and would have fallen to about 20 mK today if astrophysical feedback processes had not heated up the interglactic medium. We show how the derivative of the Compton coupling equation helps numerically to follow the decoupling process. 相似文献
546.
Ting Lu David G. Gilbank Michael L. Balogh Adam Bognat 《Monthly notices of the Royal Astronomical Society》2009,399(4):1858-1876
The global star formation rate has decreased significantly since z ∼ 1 , for reasons that are not well understood. Red-sequence galaxies, dominating in galaxy clusters, represent the population that have had their star formation shut off, and may therefore be the key to this problem. In this work, we select 127 rich galaxy clusters at 0.17 ≤ z ≤ 0.36 , from 119 deg2 of the Canada–France–Hawaii Telescope Legacy Survey (CFHTLS) optical imaging data, and construct the r '-band red-sequence luminosity functions (LFs). We show that the faint end of the LF is very sensitive to how red-sequence galaxies are selected, and an optimal way to minimize the contamination from the blue cloud is to mirror galaxies on the redder side of the colour–magnitude relation. The LFs of our sample have a significant inflexion centred at , suggesting a mixture of two populations. Combining our survey with low-redshift samples constructed from the Sloan Digital Sky Survey, we show that there is no strong evolution of the faint end of the LF (or the red-sequence dwarf-to-giant ratio) over the redshift range 0.2 ≲ z ≲ 0.4 , but from z ∼ 0.2 to ∼0 the relative number of red-sequence dwarf galaxies has increased by a factor of ∼3, implying a significant build-up of the faint end of the cluster red sequence over the last 2.5 Gyr. 相似文献
547.
Fang Huang Justin Glessner Adam Ianno Craig Lundstrom Zhaofeng Zhang 《Chemical Geology》2009,268(1-2):15-23
To provide inter-lab comparison for high-precision Mg isotope analysis, Mg isotope compositions (expressed as δ26Mg relative to DSM-3) for commercially accessible peridotite, basalt, andesite, and granite geo-standards have been measured by multi-collector inductively coupled mass-spectrometry (Nu-Plasma) using sample-standard bracketing method. There is a large tolerance of matrix cations during the measurement of Mg isotopes, as intensity ratios of 23Na/24Mg and 27Al/24Mg of about 20% only change the δ26Mg by less than 0.1‰, and low 55Mn/24Mg (<0.1) and 58Ni/24Mg (<0.01) do not cause significant mass bias either. Concentration match between samples and standards within 90% is adequate to obtain accurate isotope analysis, which also mitigates the isobaric interference of 12C14N+ on 26Mg. Organic matrix from chemical purification can cause significant analytical errors when the mass of Mg processed is small. The long-term reproducibility of δ26MgDSM-3 for samples with relatively higher MgO content is about 0.11‰ (2SD), and granites with lower MgO content is about 0.2‰ (2SD). Although the standards in this study have wide ranges of major element compositions with SiO2 from 40 to 70 wt.% and MgO from 0.75 to 49.6 wt.%, they exhibit a variation of Mg isotopic compositions with δ26Mg from −0.07 to −0.40‰. δ26Mg do not correlate with SiO2 or MgO contents, suggesting homogenous Mg isotope compositions in igneous rocks at the level of current precision, relative to low temperature samples including sediments and riverine and sea waters. Our data do not support a non-chondritic Mg isotope composition of the Earth. 相似文献
548.
David W. Peate Joel A. Baker Sveinn P. Jakobsson Tod E. Waight Adam J. R. Kent Nathalie V. Grassineau Anna Cecile Skovgaard 《Contributions to Mineralogy and Petrology》2009,157(3):359-382
We present new compositional data on a suite of historic lava flows from the Reykjanes Peninsula, Iceland. They were erupted
over a short time period between c. 940 and c. 1340 ad and provide a snap-shot view of melt generation and evolution processes beneath this onshore, 65 km long, ridge segment.
The lavas are tholeiitic basalts (MgO 6.5–9.2 wt%) and sparsely (≪5%) olivine and/or plagioclase phyric (±trace clinopyroxene).
Individual eruptive events show remarkable compositional homogeneity. Despite a limited variation in Sr–Nd isotope compositions,
high-precision double-spike Pb isotope data show tight coherent arrays that, together with correlations with incompatible
trace element ratios, indicate control by binary mixing processes. Poor correlations with elemental abundances require that
this mixing took place prior to extensive fractional crystallisation. Olivines in the historic lavas have light δ18O values (+4.2 to +4.3‰), which is likely to be a feature of the enriched mantle source to Reykjanes Peninsula lavas. High
precision Pb isotope analyses of other post-glacial Reykjanes Peninsula lavas show significant variability in 207Pb/204Pb and 208Pb/204Pb at lower 206Pb/204Pb values than in the historic lavas. This variation demonstrates that at least three compositionally distinct components
within the mantle are required to explain the Pb isotope variations within the Reykjanes Peninsula as a whole.
Electronic supplementary material The online version of this article (doi:) contains supplementary material, which is available to authorized users. 相似文献
549.
We have performed experiments to constrain the effect of sulfur fugacity (fS2) and sulfide saturation on the fractionation and partitioning behavior of Pt, Pd and Au in a silicate melt–sulfide crystal/melt–oxide–supercritical aqueous fluid phase–Pt–Pd–Au system. Experiments were performed at 800 °C, 150 MPa, with oxygen fugacity (fO2) fixed at approximately the nickel–nickel oxide buffer (NNO). Sulfur fugacity in the experiments was varied five orders of magnitude from approximately log fS2 = 0 to log fS2 = −5 by using two different sulfide phase assemblages. Assemblage one consisted initially of chalcopyrite plus pyrrhotite and assemblage two was loaded with chalcopyrite plus bornite. At run conditions pyrrhotite transformed compositionally to monosulfide solid solution (mss), chalcopyrite to intermediate solid solution (iss), and in assemblage two chalcopyrite and bornite formed a sulfide melt. Run-product silicate glass (i.e., quenched silicate melt) and crystalline materials were analyzed by using both electron probe microanalysis and laser ablation inductively coupled plasma mass spectrometry. The measured concentrations of Pt, Pd and Au in quenched silicate melt in runs with log fS2 values ranging from approximately 0.0 to −5.0 do not exhibit any apparent dependence on fS2. The measured Pt, Pd and Au concentrations in mss do vary as a function of fS2. The measured Pt, Pd and Au concentrations in iss do not appear dependent on fS2. The data suggest that fS2, working in concert with fO2, via the determinant role that these variables play in controlling the magmatic sulfide phase assemblage and the solubility of Pt, Pd and Au as lattice bound components in magmatic sulfide phases, is a controlling factor on the budgets of Pt, Pd and Au during the evolution of magmatic systems. 相似文献
550.
Annelies De Backer Stefanie Adam Jaak Monbaliu Erik Toorman Magda Vincx Steven Degraer 《Estuaries and Coasts》2009,32(6):1121-1129
The present study aims to test the application of remote sensing to address the impact of bioturbation on physical sediment
properties. Therefore, a laboratory experiment was developed, using microcosms mimicking a marine intertidal water–sediment
interface to test the influence of Corophium volutator densities on sediment properties. Three main variables (water content, clay content, and mean grain size) were measured in
three treatments (no Corophium, 5,000 Corophium per square meter, and 20,000 Corophium per square meter) after 16 days of bioturbation. Results obtained with conventional—destructive—techniques showed a significant
increase of water content and a significant, but small decrease of clay content in the presence of Corophium. The remote sensing technique detected the impact of Corophium on water content as an increase in absorption at 1,450 nm, but was not able to detect the animal impact on clay content.
This study demonstrates that remote sensing data could be significantly modified by bioturbation activities and that remote
sensing can be applied in the laboratory to address the impact of bioturbation on sediment properties. This possibly opens
new perspectives for long-term experiments concerning the role of bioturbation on sedimentary processes. 相似文献