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Regional Environmental Change - Soil carbon stocks of 29 plots along a transect through tropical Brazil showed only minor soil carbon losses after land use shift, although replacement of...  相似文献   
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Kaupp G  Schmeyers J  Boy J 《Chemosphere》2001,43(1):55-61
Unexpected organic solid-state reactions in the gas-solid and stoichiometric solid-solid versions are highly promising new tools for solvent-free sustainable synthesis and production if they occur with 100% yield. Costly workup is obsolete, no wastes are formed and resources and energy saved. More than 500 published 100%-yield, solid-state reactions in 25 reaction types cover virtually all fields of synthetic organic chemistry. Atomic force microscopy (AFM) reveals that solid-state reactions require long-range molecular movements and are strictly and sensibly guided by the crystal packing. Three steps govern the issue: phase rebuilding, phase transformation, and crystal disintegration (detachment). If one of these fails, or if liquid phases are not avoided, the reaction will usually not run to completion. Repeated creation of fresh contacts of crystallites is essential in solid-solid reactions. New, otherwise inaccessible and highly reactive products are most easily obtained. Cooling below eutectic temperatures, but also thermal activation above room temperature, may be necessary. Liquids may be solidified by cooling or inclusion complexation. Typical single-step, multi-step and cascade reactions have been performed with 100% yield using commonly available starting materials in various fields. Upscaling to the kilogram scale has been achieved under various conditions. Further upscaling to technical size productions seems possible.  相似文献   
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典型气田土壤铁还原活性与微生物群落关系研究   总被引:1,自引:0,他引:1  
由微生物驱动的土壤铁还原过程在铁的生物地球化学循环中起到重要作用,该过程还可与土壤重金属的转化及石油烃类有机污染物的降解等过程相偶联.油气田土壤常具有潜在有机污染物风险,本研究以重庆涪陵页岩气田的土壤(潜在烃类有机物污染风险)为对象,测定土壤铁还原活性(Iron Reducing Potential,IRP),并利用Illumina Miseq测序解析其中的铁还原微生物类群,进而探讨IRP、土壤基本性质及微生物群落之间的关系.结果表明,该区域土壤铁还原菌群的优势菌门为厚壁菌门(Firmicutes)、变形菌门(Proteobacteria)和拟杆菌门(Bacteroidetes).与低IRP样品相比,高IRP样品中Pseudomonas、norank PeptococcaceaeLentimicrobium等菌属具有较高的相对丰度.基于各样品OTU (Operational Taxonomic Unit)组成的PCoA (Principal Co-ordinates Analysis)分析表明,高、中及低IRP样品中铁还原菌群落结构差异显著(R2=0.25,p<0.01),且一些分别属于Acetoanaerobium、Proteiniphilum、Petrimonas、TessaracoccusExiguobacterium菌属中的OTUs在高IRP样品中显著上调.结构方程模型表明,铁还原微生物的群落结构是直接决定土壤IRP的主要因子,土壤氨氮及有效磷均可通过影响微生物群落结构来间接影响IRP,且氨氮还可通过直接影响有效磷来间接影响土壤IRP.本研究揭示了影响典型页岩气田土壤铁还原活性的关键因子及微生物机制,为进一步深入研究铁还原条件下土壤有机污染物去除的微生物机制打下基础.  相似文献   
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In recent years, many political parties have created new forms of affiliation and have justified the blurring of membership boundaries with claims that sympathisers would be more representative of the electorate and less radical. Such claims are based on ‘popular wisdom’ inspired by John May’s ‘special law of curvilinearity’, which states that activists hold more extreme views than voters and elites. When this expectation has been tested, results have been at best inconclusive; but testing has so far never used a single survey to compare different groups. Using an online survey of Europe Ecologie Les Verts party members and their extended networks (affiliated supporters, lapsed members, sympathisers), relationships between ideological differences and degree of investment in party activities and decision-making are analysed. The results, contradicting May’s special law along all ideological dimensions other than intra-party democracy, can be explained if May’s narrowly instrumental assumptions about preference formation are rejected.  相似文献   
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Regional Environmental Change - This article describes the design of a new model-based assessment framework to identify and analyse possible future trajectories of agricultural development and...  相似文献   
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Regional Environmental Change - The calculation of robust estimates of future greenhouse gas emissions due to agriculture is essential to support the framing of the Brazilian climate change...  相似文献   
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