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701.
城市化过程中黑碳的土壤记录及其环境指示意义 总被引:6,自引:0,他引:6
以南京市为对象,通过3组共计10个土壤剖面的采样,用湿化学氧化法分析了土壤有机碳(organic carbon,OC)和黑碳(black carbon,BC)的含量.研究发现,南京城市土壤剖面中黑碳含量的变幅为0.22~32.19 g·kg-1,平均值为4.35 g·kg-1.第1组城市土壤剖面中黑碳含量的平均值为0.91 g·kg-1,第2组为8.62 g·kg-1,第3组为3.72 g·kg-1.城市土壤剖面中BC/OC值的变幅为0.03~1.59,平均值为0.29,其中BC/OC平均值的大小顺序是:受古代工业活动影响的第2组最大,受现代工业和交通人为活动影响的第3组次之,受古代居民生活影响的第1组最低.研究认为,在城市化过程中,由于工业和交通等人类活动引起的生物物质和矿物燃料(煤、石油等)燃烧产生的BC在土壤中都有不同程度的沉积和记录.BC含量和BC/OC值的大小可能在一定程度上反映了不同人为影响过程和城市土壤的污染程度.城市区域BC的主要来源是矿物燃料燃烧,其中表层(现代层)主要来自交通车辆(尤其是柴油为动力的机车)排放的颗粒物质,而在古代(文化层)可能与燃烧用煤历史有关. 相似文献
702.
Urea hydrolysis and recovery of nitrogen and phosphorous as MAP
from stale human urine 总被引:1,自引:0,他引:1
LIU Zhigang ZHAO Qingliang WANG Kun LEE Duujong QIU Wei WANG Jianfang 《环境科学学报(英文版)》2008,20(8):1018-1024
Laboratory-scale tests for magnesium ammonium phosphate(MAP)precipitation following urea hydrolysis of human urine were conducted using orthogonal experiment design.The effects of initial pH,temperature and the volumetric ratios of stale urine to fresh urine,on urea hydrolysis in urine were studied to determine the final hydrolysis time to recover most nitrogen from separated human urine by MAP.With a volumetric ratio of stale to fresh urine>10% and at temperature≥20℃,urea hydrolysis could be completed i... 相似文献
703.
We used linear and multivariate models to examine the associations between geography, biodiversity, per capita economic output, national spending on conservation, governance, and cultural traits in 55 countries. Cultural traits and social metrics of modernization correlated positively with national spending on conservation. The global distribution of this spending culture was poorly aligned with the distribution of biodiversity. Specifically, biodiversity was greater in the tropics where cultures tended to spend relatively less on conservation and tended to have higher collectivism, formalized and hierarchical leadership, and weaker governance. Consequently, nations lacking social traits frequently associated with modernization, environmentalism, and conservation spending have the largest component of Earth's biodiversity. This has significant implications for setting policies and priorities for resource management given that biological diversity is rapidly disappearing and cultural traits change slowly. Therefore, we suggest natural resource management adapt to and use characteristics of existing social organization rather than wait for or promote social values associated with conservation spending. Supporting biocultural traditions, engaging leaders to increase conservation commitments, cross‐national efforts that complement attributes of cultures, and avoiding interference with nature may work best to conserve nature in collective and hierarchical societies. Spending in modernized nations may be a symbolic response to a symptom of economic development and environmental degradation, and here conservation actions need to ensure that biodiversity is not being lost. 相似文献
704.
With large quantity of flux (Na2CO3), lead can be recovered from the funnel glass of waste cathode-ray tubes via reduction–melting at 1000 °C. To reduce flux cost, a technique to recover added flux from the generated oxide phase is also important in order to recycle the flux recovered from the reduction–melting process. In this study, the phase separation of sodium and the crystallization of water-soluble sodium silicates were induced after the reduction–melting process to enhance the leachability of sodium in the oxide phase and to extract the sodium from the phase for the recovery of Na2CO3 as flux. A reductive atmosphere promoted the phase separation and crystallization, and the leachability of sodium from the oxide phase was enhanced. The optimum temperature and treatment time for increasing the leachability were 700 °C and 2 h, respectively. After treatment, more than 90% of the sodium in the oxide phase was extracted in water. NaHCO3 can be recovered by carbonization of the solution containing sodium ions using carbon dioxide gas, decomposed to Na2CO3 at 50 °C and recycled for use in the reduction–melting process. 相似文献
705.
Incentivizing biodiversity conservation in artisanal fishing communities through territorial user rights and business model innovation
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C. Josh Donlan 《Conservation biology》2015,29(4):1076-1085
Territorial user rights for fisheries are being promoted to enhance the sustainability of small‐scale fisheries. Using Chile as a case study, we designed a market‐based program aimed at improving fishers’ livelihoods while incentivizing the establishment and enforcement of no‐take areas within areas managed with territorial user right regimes. Building on explicit enabling conditions (i.e., high levels of governance, participation, and empowerment), we used a place‐based, human‐centered approach to design a program that will have the necessary support and buy‐in from local fishers to result in landscape‐scale biodiversity benefits. Transactional infrastructure must be complex enough to capture the biodiversity benefits being created, but simple enough so that the program can be scaled up and is attractive to potential financiers. Biodiversity benefits created must be commoditized, and desired behavioral changes must be verified within a transactional context. Demand must be generated for fisher‐created biodiversity benefits in order to attract financing and to scale the market model. Important design decisions around these 3 components—supply, transactional infrastructure, and demand—must be made based on local social‐ecological conditions. Our market model, which is being piloted in Chile, is a flexible foundation on which to base scalable opportunities to operationalize a scheme that incentivizes local, verifiable biodiversity benefits via conservation behaviors by fishers that could likely result in significant marine conservation gains and novel cross‐sector alliances. Incentivar la Conservación de la Biodiversidad con Comunidades de Pesca Artesanal por medio de Derechos de Uso Territorial y la Innovación de Modelos de Negocio 相似文献
706.
基于政府视角的人力资本投资分析 总被引:4,自引:0,他引:4
本文首先分析了政府在人力资本投资中的作用,然后从实现政府工作目标的角度探讨了人力资本投资的重要意义,最后提出增加人力资本投资的政策性建议. 相似文献
707.
Dr Jérôme Solassol Haíssam Rahil Vincent Sapin Didier Lemery Bernard Dastugue Odile Boespflug-Tanguy Isabelle Creveaux 《黑龙江环境通报》2003,23(4):287-291
Prenatal diagnosis of fetal trisomy 21 is usually performed by cytogenetic analysis. This requires lengthy laboratory procedures, high costs and is unsuitable for large-scale screening of pregnant women. Today, trisomy 21 can be rapidly diagnosed within 24 h by molecular analysis of uncultured fetal cells using the semi-quantification of fluorescent PCR products from short tandem repeat (STR) polymorphic markers. The aim of our study was to test a chromosome quantification method on the basis of the analysis of fluorescent PCR products derived from non-polymorphic target genes. Co-amplification of a portion of DSCR1 (Down syndrome Critical Region 1) and the reference gene, CFTR (cystic fibrosis transmembrane regulator) enabled molecular detection of trisomy 21. Our method was successfully tested on a total of 154 amniotic fluids in a blind prospective study. Calculation of the DSCR1/CFTR ratio allowed us to distinguish between 152 normal amniotic fluids (mean ratio 0.99) and 2 amniotic fluids presenting a trisomy 21 status (DSCR1/CFTR ratio of 1.53 and 1.61, respectively). The results obtained by conventional cytogenetic analysis and our quantitative PCR method were concordant in every case. Our gene-based fluorescent PCR approach represents an alternative molecular method for rapid and reliable detection of trisomy 21, which can be helpful in the prenatal diagnosis of women at high risk of fetal trisomy 21. Copyright © 2003 John Wiley & Sons, Ltd. 相似文献
708.
709.
Sincetheinternationalgeophysicalyear(IGY,1957—1958),Antarcticahasbeentheobjectofintensivescientificinvestigationbyteamsofscientists... 相似文献
710.
Sun Kee Hong 《环境科学学报(英文版)》1999,11(2):181-187
Throughthestatisticsandtheanalysisoflandscapemap,changesoflandsuseregimeandlandscapestructureduring20yearswereinvestigatedin... 相似文献