酵母提取物对葡萄糖发酵生产生物破乳菌Alcaligenes sp. S-XJ-1的影响

以从石油污染的土壤中筛选出1株生物破乳菌Alcaligenes sp.S-XJ-1为对象,考察了以葡萄糖为碳源时添加酵母提取物对生物破乳菌菌体性质、破乳性能以及菌体元素组成的影响.结果表明,酵母提取物的投加能够有效提高生物破乳菌产量,在酵母提取物浓度为5 g.L-1时,生物破乳菌产量达到3.0 g.L-1,此时葡萄糖利用率亦达到最大的58%.随着酵母提取物的投加浓度的增大,培养得到的菌体破乳性能提高,在投加浓度为10 g.L-1时,破乳率达到76%;而培养得到的菌体C/N有所降低,对其菌体表面蛋白进行提取测定发现菌体总蛋白含量升高,这与FTIR分析破乳菌菌体表面蛋白质类物质提高的结论一致.推测该生物破乳菌菌体蛋白含量的提高增强了菌体的破乳性能,菌体蛋白类物质是影响其破乳性能的关键组分之一.     

秸秆还田少免耕对冲积土微生物多样性及微生物碳氮的影响

土壤微生物是耕地质量的重要指标,为阐明秸秆还田少免耕对土壤质量的影响及其机理,在成都平原(温江)冲积水稻土区,开展了水稻–小麦/油菜轮作秸秆还田培肥定位试验(2003～2008年),在小麦生长季节,系统研究了土壤耕层微生物数量和微生物生物量的变化特征.结果表明,秸秆还田翻耕与秸秆还田免耕的土壤耕层微生物总量分别增加了51.7%、12.8%,土壤微生物数量增加主要来自土壤细菌数量的增加;从小麦全生育期看,在小麦分蘖期的增加幅度高于小麦播种期和小麦收获后,有利于促进小麦养分吸收与生长发育.秸秆还田少免耕显著增加了微生物生物量,秸秆还田翻耕和秸秆还田免耕处理土壤微生物碳总量分别比对照提高74.1%、25.8%,土壤微生物氮分别提高60.2%和12.1%.秸秆还田循环利用显著增加了土壤微生物数量和生物量,有利于土壤养分循环与转化,有利于提高土壤有机质含量并改善有机质质量,是耕地质量建设的重要途径.     

Dynamic relationship between precious metals

We use a relatively new approach to endogenously detect the volatility shifts in the returns of four major precious metals (gold, silver, platinum and palladium) from 1999 to 2013. We reveal that the turbulent year of 2008 has no significant effect on volatility levels of gold and silver however causes an upward shift in the volatility levels of palladium and platinum. Using the consistent dynamic conditional correlations, we show that precious metals get strongly correlated with each other in the last decade which reduces the diversification benefits across them and indicates a convergence to a single asset class. We endogenously detect the shifts in these dynamic correlation levels and reveal uni-directional volatility shift contagions among precious metals. The results show that gold has a uni-directional volatility shift contagion effect on all other precious metals and silver has a similar effect on platinum and palladium. However, the latter two do not matter in terms of volatility shift contagion. Thus, investors that hedge with precious metals should, in particular, monitor the volatility levels of gold and silver.     

Imagined citizens and participation: Local Agenda 21 in two communities in Sweden and Austria

Abstract

Local Agenda 21 (LA21), which has its roots in the UN Conference on Environment and Development held in 1992 in Rio de Janeiro, aims at fostering processes of sustainable development on a local level. In this article, we compare the LA21 processes of two cities, Helsingborg in Sweden and Vienna in Austria, to seek insight into the varying implementation approaches of common international political commitments. Our focus of analysis is on the social organisation of the two processes, the way local residents are integrated into LA21 work, and especially the political images of citizens—which we call ‘imagined citizens’—that different actor groups hold. The results of the study illustrate two almost diametrically opposed organisational forms of local sustainability governance, the Swedish process relying on a more expert-led, technocratic model of implementation and the Austrian process strongly building on deliberative forms of citizen participation.     

Variation of reservoir fluid property during the high pressure air injection process

This research aimed at determining the variation of reservoir fluid property during the high-pressure air injection process. For this purpose, the forward multiple contact experiment was employed by pressure–volume–temperature (PVT) system to investigate the physical property variation of the crude oil and the complex oxidation reactions. The results show: under the relative low temperature and pressure condition, instead of carbon dioxide, carbon monoxide dominates the products in the air phase. The gas/oil ratio and volume ratio increased due to the generated gas while the viscosity and density achieved a descending trend. The colloid and bitumen in the oil phase reduced by half but the amount of wax achieved a small increase. The low-temperature oxidation and pyrolysis reactions caused the fluctuated change of the different compounds. The amount of light compounds decreased at the beginning and then increased while that of heavy compounds showed the opposite trend. But at last, due to the H/C ratio, the light compounds increased to more than their initial value.     

C/N对Carrousel 2000氧化沟同步脱氮除磷的影响研究

就C/N对Carrousel 2000氧化沟同步脱氮除磷的影响进行了研究。结果表明,进水C/N值在5～13之间时,进水C/N不影响氧化沟系统对NH₃-N的去除效果。出水NH₃-N浓度＜1 mg/L,平均去除率达到97.40%。当C/N低于11时,TN、TP的去除率随C/N的升高而快速大幅提高,分别从5时的26.47%和14.99%升至11时的93.48%和97.03%。当C/N＞11时,氧化沟TN去除率达到93.48%,TP去除率接近100%,氧化沟具有了良好的同步脱氮除磷的效果,出水水质满足国家《城镇污水处理厂污染物排放标准》(GB 18918-2002一级A标准)要求。TP去除率与TN去除率相关系数R₂＝0.985。     

Duration and characteristics of metal price cycles

This paper addresses the fluctuations in real metal prices: are they simply random variations or do they display some degree of cyclicality? This study identifies peaks and troughs in the inflation adjusted prices for 14 metals, using monthly average data from January 1947 through December 2007. Duration dependence testing, which is performed on the expansions, contractions, and full cycles, finds many cases in which the duration of these phases are not purely random and have some degree of cyclicality. Additional characterization show that contractions generally persist longer than expansions (in contrast to macroeconomic cycles) that long-term real prices have been trendless, and that the amplitude of price changes over the phases has little regularity. For those performing this type of analysis, the appendices explain the procedures for dating turning points and assessing duration dependence.     

不同恢复年限刺槐林土壤碳、氮、磷含量及其生态化学计量特征

地处西秦岭山地的甘肃天水吕二沟小流域土壤侵蚀问题严重,上世纪五六十年代开始,当地政府在研究区实施了多年的生态恢复措施以保持水土,但目前尚未有植被恢复对土壤生态计量特征的系统调查.分析不同林龄人工林土壤碳、氮、磷含量及其生态化学计量特征可在一定程度上揭示土壤养分的限制情况.选取黄土丘陵沟壑区不同生长年限(5、20、40、...     

Long memory in energy futures markets: Further evidence

This paper investigates long memory (or long-range dependence) in price returns and volatilities of energy futures contracts with different maturities. Based on a modified rescaled range analysis and three local Whittle methods, the results from rolling sample test suggest that the returns showed little or no long-range dependence over time but the volatilities displayed significant time-varying long-range dependence. Our evidence shows that some extreme events could cause long memory in returns and volatilities, leading to market inefficiency. Employing multiscale analysis, we find that the returns displayed no long-range dependence for any of the chosen time scales. Significant long-range dependence only existed in volatilities for daily time scales but not for monthly or yearly time scales.     

Influence of the composition of the initial mixtures on the chemical composition,physicochemical properties and humic-like substances content of composts

The influence of the proportion of C- and N-rich raw materials (initial C/N ratio) and bulking agent on the chemical functional groups composition, humic-like substances (HS-like) content and physicochemical properties of composts was assessed. To achieve these goals, seven initial mixtures (BA1–6 and C1) of dog food (N-rich raw material) were composted with wheat flour (C-rich raw material). Composts were analyzed in terms of chemical functional groups, physicochemical, maturity and stability parameters.The C-rich raw material favored the formation of oxidized organic matter (OM) during the composting process, as suggested by the variation of the ratios of the peaks intensity of FT-IR spectra, corresponding to a decrease of the polysaccharides and an increase of aromatic and carboxyl-containing compounds. However, although with high proportion of C-rich raw material, mixtures with low initial C/N seems to have favored the accumulation of partially oxidized OM, which may have contributed to high electrical conductivity values in the final composts. Therefore, although favoring the partial transformation of OM into stabilized HS-like, initial mixtures with high proportion of C-rich raw material but with low initial C/N led to unstable composts.On the other hand, as long as a high percentage of bulking agent was used to promote the structure of biomass and consequently improve of the aeration conditions, low initial C/N was not a limiting factor of OM oxidation into extractable stabilized humic-like acids.