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941.
This paper examines the use of community-based social marketing (CBSM) techniques to encourage more sustainable behaviors within community-based co-managed (CBCM) fisheries. An overview of the CBSM theory and practice is provided along with an evaluation of how CBSM has been successfully used to foster sustainable behaviors in other analogous resource management sectors (e.g., agriculture). It is argued that CBSM is highly conducive to CBCM fisheries arrangements due to the shared goals of stakeholder participation and empowerment and that, currently, CBSM has been overlooked as a tool for fostering more sustainable behaviors, particularly in the case of CBCM fisheries. 相似文献
942.
An ocean model was used to examine whether the scatterometer winds can improve the model performance both dynamically and thermodynamically. Comparisons were done using QuikSCAT and NCEP2 winds for both the mean and variability from 2000 to 2004. The comparisons showed that the model forced by QuikSCAT winds gives more realistic mean SST, 20 °C isotherm depth (Z20), and latent heat flux than NCEP2 winds do. Sensitivity experiments indicated that QuikSCAT mean wind stress is important for the improved mean SST, Z20, and latent heat release to the atmosphere in the eastern Pacific. QuikSCAT wind speed, through its effect on the turbulent heat fluxes, is most important for the mean SST in the western Pacific. Finally, there were comparable correlations with observations of both SST and Z20 on the intra-seasonal time scale between the model forced with QuikSCAT winds and the model forced with NCEP2 winds. 相似文献
943.
Sweeney R. J. Thompson A. B. Ulmer P. 《Contributions to Mineralogy and Petrology》1993,115(2):225-241
Melting experiments were performed on a natural mica-amphibole-rutile-ilmenite-clinopyroxene (MARID) sample from the Kaapvaal mantle lithosphere (AJE137) at 20 to 35 kbar and 800 to 1450°C. A solidus was determined at 1260°C and 30 kbar above which phlogopite, clinopyroxene and olivine were stable with an alkali-rich silicate melt. Olivine is the only crystallizing phase just below the liquidus of the AJE137 bulk composition and K-richterite was only stable in the subsolidus region ( 1100°C at 30 kbar). These results are consistent with previous studies in more simple systems. In experiments with 10 wt% added water the solidus was depressed by ca. 300°C and K-richterite was stabilized above this solidus. MARIDs represent a potential lowtemperature component in the lithospheric mantle beneath the Kaapvaal Craton of southern Africa. The addition of > 10 wt% water (with less than a 120°C rise of temperature above the geotherm) to this mantle region would create conditions for the melting of this component. This may then be incorporated in any continental flood basalt parent magma that traverse this lithospheric mantle. The derivation of MARIDs from a silicate melt of their bulk composition, even if water saturated, is considered unlikely as such small degree melts could not sustain the elevated liquidus temperatures required (> 1200°C at 30 kbar) in a cold (< 800°C at 30 kbar) mantle lithosphere. MARID xenoliths may be produced by the interaction of an alkali-rich fluid with a peridotite or as the residue to a group II kimberlitic parent magma that has undergone fractionation of olivine and the exsolution of a carbonatite component. 相似文献
944.
美国西部克罗拉多CrippleCreek地区浅成低温金-碲化物矿床成因及相关之碱性火成岩自1891年发现至今,CrippleCreek地区已产金653t之多,成为全美第二大金产地.金矿床产于被元古宙基底岩石包围着的狭小的(18km2)渐新统火山杂岩中... 相似文献
945.
敦德冰芯中微粒含量与沙尘暴及气候的关系 总被引:9,自引:2,他引:9
在敦德冰芯不同粒径(>2.0um,2.0~25um,>5.04um)的微粒数据处理基础上,进行了微粒的变化特征以及微粒所揭示的气候信息分析,并将其与小冰期以来的气候变化记录进行了对比.结果表明,微粒含量变化与极地微粒研究所得的结论基本一致,即微粒含量高时,气候多为冷干;微粒含量低时,气候多为暖湿微粒变化异常于这一规律时,多为尘暴发生之时微粒含量的多少与当地的大风强度、地形、尘暴的规模、频率和强度有关 相似文献
946.
Ben?HayesEmail authorView authors OrcID profile Lewis?D.?Ashwal Susan?J.?Webb Grant?M.?Bybee 《Contributions to Mineralogy and Petrology》2017,172(2-3):13
The Bellevue drillcore intersects ~3 km of Main and Upper Zone cumulates in the Northern Limb of the Bushveld Complex. Main Zone cumulates are predominately gabbronorites, with localized layers of pyroxenite and anorthosite. Some previous workers, using bulk rock major, trace and isotopic compositions, have suggested that the Main Zone crystallized predominantly from a single pulse of magma. However, density measurements throughout the Bellevue drillcore reveal intervals that show up-section increases in bulk rock density, which are difficult to explain by crystallization from a single batch of magma. Wavelet analysis of the density data suggests that these intervals occur on length-scales of ~40 to ~170 m, thus defining a scale of layering not previously described in the Bushveld Complex. Upward increases in density in the Main Zone correspond to upward increases in modal pyroxene, producing intervals that grade from a basal anorthosite (with 5% pyroxene) to gabbronorite (with 30–40% pyroxene). We examined the textures and mineral compositions of a ~40 m thick interval showing upwardly increasing density to establish how this type of layering formed. Plagioclase generally forms euhedral laths, while orthopyroxene is interstitial in texture and commonly envelops finer-grained and embayed plagioclase grains. Minor interstitial clinopyroxene was the final phase to crystallize from the magma. Plagioclase compositions show negligible change up-section (average An62), with local reverse zoning at the rims of cumulus laths (average increase of 2 mol%). In contrast, interstitial orthopyroxene compositions become more primitive up-section, from Mg# 57 to Mg# 63. Clinopyroxene similarly shows an up-section increase in Mg#. Pyroxene compositions record the primary magmatic signature of the melt at the time of crystallization and are not an artefact of the trapped liquid shift effect. Combined, the textures and decoupled mineral compositions indicate that the upward density increase is produced by the downward infiltration of noritic magma into a previously emplaced plagioclase-rich crystal mush. Fresh noritic magma soaked down into the crystallizing anorthositic mush, partially dissolving plagioclase laths and assimilating Fe-enriched pore melt. The presence of multiple cycles showing upward increases in density in the Bellevue drillcore suggests that downward magma infiltration occurred episodically during crystallization of the Main Zone. 相似文献
947.
A Properly Developed Consensus from a Proficiency Test is,for All Practical Purposes,Interchangeable with a Certified Value for a Matrix Reference Material Derived from an Interlaboratory Comparison 下载免费PDF全文
Michael Thompson 《Geostandards and Geoanalytical Research》2018,42(1):91-96
A properly developed consensus from a proficiency test is, for all practical purposes, interchangeable with a certified value derived from an interlaboratory comparison. But some scientists have doubts about the metrological status of such values. In particular, the materials are not regarded as equivalent to certified reference materials (CRM) because of a lack of traceability of the consensus value. However, the detailed considerations in this study show that such a distinction is without foundation. The following issues are addressed. (a) Misgivings about the traceability of an interlaboratory consensus are found to be insubstantial because chemical measurements are hardly ever fully traceable. (b) Reproducibility (i.e., interlaboratory) conditions account for all sources of variation in results other than long‐term stability, so lead to a valid estimate of uncertainty. (c) Certification of a reference material according to ISO procedures is homologous with a proficiency test and no more secure against bias in the characterised value and its standard error. In particular, residual (common) bias cannot be fully addressed in either approach. (d) A consensus in itself attests to a valid outcome. (e) Proficiency test providers have access to a powerful method of monitoring long‐term stability that is denied to CRM producers. 相似文献
948.
Seasonal and inter-annual variability of the mixed layer temperature in the Southern South China Sea (SSCS) is investigated using a regional ocean circulation model simulation. The mixed layer depth (MLD) over the SSCS exhibits a strong seasonal signal with deeper MLDs during the northeast and southwest monsoons. The main factor that drives the mixed layer temperature variation in the SSCS is the air-sea heat fluxes, with vertical ocean processes acting as a relatively weak negative feedback. In general, the budget analysis demonstrates a net balance between the vertical ocean processes and surface heat flux during the pre-monsoon and southwest monsoon. Northeast monsoon period is noted by an offsetting of surface heat flux, horizontal and vertical ocean processes. The first dominant mode of mixed layer temperature inter-annual variability in the SSCS shows significant correlation (0.34) with the El Nino phenomenon in the Pacific Ocean and is best correlated (0.67) with a lag of 5 months. 相似文献
949.
J. Rudolph R. S. Anderson K. V. Czapiewski E. Czuba D. Ernst T. Gillespie L. Huang C. Rigby A. E. Thompson 《Journal of Atmospheric Chemistry》2003,44(1):39-55
A technique was developed that allows the determination of the stable carbon isotope ratio of isoprene in air. The method was used for a limited number of ambient measurements as well as laboratory studies of isoprene emitted from Velvet Bean (Mucana pruriens L. var. utilis), including the light and temperature dependence. The mean stable carbon isotope ratio ( 13C) of isoprene emitted from Velvet Bean (Mucana pruriens L. var. utilis) for all our measurements is –27.7 ± 2.0 (standard deviation for 23 data points). Our results indicate a small dependence of the stable carbon isotope ratios on leaf temperature and photosynthetic photon flux density (PPFD). The light dependence is 0.0026 ± 0.0012/( mol of photons m–2 s–1) for the studied range from 400 to 1700 mol of photons m–2 s–1. The temperature dependence is 0.16 ± 0.09/K. On average, the emitted isoprene is 2.6 ± 0.9 lighter than the leaf carbon. An uncertainty analysis of the possibility to use stable carbon isotope ratio measurements of isoprene for estimates of its mean photochemical age suggests that meaningful results can be obtained. This is supported by the results of a small number of measurements of the stable carbon isotope composition of ambient isoprene at different locations. The results range from approximately –29 to –16. They are consistent with vegetation emissions of isoprene that is slightly depleted in 13C relative to the plant material and enrichment of 13C in the atmosphere due to isotope fractionation associated with the reaction with OH-radicals. The stable carbon isotope ratio of ambient isoprene at locations directly influenced by isoprene emissions is very close to the values we found in our emission studies, whereas at sites located remote from isoprene emitting vegetation we find substantial enrichment of 13C. This suggests that stable carbon isotope ratio measurements will be a valuable, quantitative method to determine the extent of photochemical processing of isoprene in ambient air. 相似文献
950.
Transplanted mussels and diffusive gradients in thin films (DGT) were used to assess levels of cadmium, copper, lead and zinc at four sites situated inside and outside of two enclosed marinas, near Melbourne, Australia. Mussels accumulated all metals except cadmium. Over one year, there were large temporal differences in tissue metal levels in mussels, but differences between sites were only apparent for copper and lead. DGT showed temporal differences of the same kind as those seen in the mussels, but appeared to have more power to discriminate between sites. DGT found higher copper levels inside marinas than outside, and high levels of zinc were found inside one marina. Levels of copper and zinc were high enough to be of environmental concern for one site. The effect of fouling on DGT measurements will have to be quantified, or avoided by the use of multiple short-term exposures, if the technique is to become a widespread in situ monitoring tool. 相似文献