污泥厌氧发酵产酸关键影响因素的函数模型研究

本研究以城市剩余污泥预处理液作为底物,调节底物不同C/N比,测定了厌氧发酵过程中几种关键酶的酶活及发酵产物乙酸、丙酸及丁酸的浓度.同时,利用Matlab软件通过回归分析和函数拟合构建了C/N比-关键酶活-酸产量之间的多项式函数模型,发现所建立的二元三次多项式模型的拟合优度R2均大于0.9,且残差平方和较小,因此,判定二元三次多项式更适合描述C/N比-关键酶活-酸产量的数学关系.最后,建立了关键酶活、C/N比和产酸量三因素间的曲面模型,发现该模型能够很好地描述污泥厌氧发酵中C/N比条件对关键酶和产酸类型的影响,并能进一步预测C/N比所对应的酶活和产酸发酵类型,可为今后的实验研究及工程放大提供理论参考.     

The metabolic fate of 14C‐parathion by some fresh water phytoplankton and its possible effects on the algal metabolism

Abstract

The growth and total carbohydrate contents of Nostoc muscorum and Tolypothrix tenuis were greatly and significantly reduced by the application of parathion. “Chlorophyll a”, carotene biosynthesis and the rate of glucose absorption were enhanced after supplementation of parathion to the culture media of both cyanobacteria. Nitrogen released to the media, total nitrogen content and total nitrogen fixed were increased in both organisms‐ Increase in protein content was accompanied by remarkable drop in amino, peptide and ammonia fractions‐ Phosphorus uptake, RNA, DNA and total phosphorus content were accelerated to reach maximum accumulation at the highest insecticide level. In metabolism study using ¹⁴C‐labelled compound, parathion was readily degraded by Nostoc and Tolypothrix. Following ten days incubation, the aqueous fractions contained 21.1% and 18.1% of the initial activity in Nostoc and Tolypothrix respectively. TLC analysis of the hydrolytic products revealed the presence of three metabolites: p‐aminophenol, p‐nitrophenol and aminoparathion.     

A spatial approach to combatting wildlife crime

Poaching can have devastating impacts on animal and plant numbers, and in many countries has reached crisis levels, with illegal hunters employing increasingly sophisticated techniques. We used data from an 8‐year study in Savé Valley Conservancy, Zimbabwe, to show how geographic profiling—a mathematical technique originally developed in criminology and recently applied to animal foraging and epidemiology—can be adapted for use in investigations of wildlife crime. The data set contained information on over 10,000 incidents of illegal hunting and the deaths of 6,454 wild animals. We used a subset of data for which the illegal hunters’ identities were known. Our model identified the illegal hunters’ home villages based on the spatial locations of the hunting incidences (e.g., snares). Identification of the villages was improved by manipulating the probability surface inside the conservancy to reflect the fact that although the illegal hunters mostly live outside the conservancy, the majority of hunting occurs inside the conservancy (in criminology terms, commuter crime). These results combined with rigorous simulations showed for the first time how geographic profiling can be combined with GIS data and applied to situations with more complex spatial patterns, for example, where landscape heterogeneity means some parts of the study area are less likely to be used (e.g., aquatic areas for terrestrial animals) or where landscape permeability differs (e.g., forest bats tend not to fly over open areas). More broadly, these results show how geographic profiling can be used to target antipoaching interventions more effectively and more efficiently and to develop management strategies and conservation plans in a range of conservation scenarios.     

Biological Decolorization of C.I. Basic Green 4 Solution by Chlorella sp.： Effect of Operational Parameters

In recent years, the ability of microorganisms to decolorize textile wastewater has received great attention due to the environmental persistence and toxicity of these pollutants. In this paper biological decolorization of triphenylmethane dye, C.I. Basic Green 4 (BG 4), by Chlorella species was investigated. The effect of operational parameters (temperature, pH, initial dye concentration and algal concentration) on decolorization efficiency was examined. Results indicated that the desired initial pH was 9. The stability and efficiency of the algae in long-term repetitive operations were also examined. Michaelis-Menten kinetics was employed to describe the apparent correlation between the decolorization rate and dye concentration. The optimal kinetic parameters, Vmax (specific decolorization rate) and Km (maximum specific decolorization rate) were 4.6 mg dye g cell-1 h-1and 151.0 mg L-1, respectively. Fig 10, Tab 2, Ref24     

Prenatal diagnosis of Fanconi anemia (Group C) subsequent to abnormal sonographic findings

Manifestations of Fanconi Anemia Complementation Group C (FA-C) include multiple major congenital malformations, hypoplastic radius, absent thumb, growth retardation, elfin-like facial features, microphthalmia, microcephaly, café-au-lait spots, early onset of hematologic disease and poor survival (Auerbach, 1997). We describe two cases in which second-trimester sonographic findings led to parental carrier testing for FA-C and subsequent prenatal diagnosis of affected fetuses. Copyright © 2005 John Wiley & Sons, Ltd.     

Positive framing does not solve the tragedy of the commons

We investigate whether positive framing increases cooperation in three social dilemmas with slightly different properties: a linear public goods (PG) game, a non-linear PG game, and a common pool resource (CPR) game. Results from our laboratory experiments show that contributions to a linear PG are higher if the externality is framed positively, rather than negatively, corroborating earlier findings by Andreoni (1995). By contrast, we find no such framing effects in the non-linear PG game or the CPR game. In these games, the best response in the material payoffs is to contribute less if others contribute more, counteracting effects of pro-social preferences. Positive framing therefore does not help to solve the tragedy of the commons.     

拉萨市气溶胶中碳同位素的组成及季节变化

2006年8月～2007年7月,在西藏拉萨市西郊(29°38′N,91°01′E)采集了30个大气总悬浮颗粒物(TSP)样品,利用14C定量区分了碳质气溶胶的生物和化石来源并分析了其季节变化特征.结果表明,碳质气溶胶中生物碳所占比例的fc值在0.357～0.702之间变化,均值为0.493,明显高于东京和北京等大城市地区的fc均值,但低于Launceston等郊区或偏远地区的fc均值,说明拉萨碳质气溶胶的生物来源占较大比例.fc值季节变化明显,冬季的均值最大,春季逐渐降低,夏、秋季较低.冬季高值与拉萨西郊当地居民使用木材、农业废弃物、干牛粪等燃料的能源结构密切相关;夏、秋季fc值低说明化石碳的增加,与旅游旺季机动车尾气排放增加等相关.δ13CTC变化范围为-26.4‰～-25.1‰,年均值为-25.8‰,其季节变化特征并不明显,但夏季δ13CTC偏大可能与化石碳增多有关.全年碳质气溶胶的δ13CTC变化范围很小,结合fc值的季节变化推断拉萨碳质气溶胶总体上受到生物质燃烧和机动车尾气等几个均匀混合的稳定来源影响.     

Effects of Dram Shop,Responsible Beverage Service Training,and State Alcohol Control Laws on Underage Drinking Driver Fatal Crash Ratios

Objectives: In this study, we aimed to determine whether three minimum legal drinking age 21 (MLDA-21) laws—dram shop liability, responsible beverage service (RBS) training, and state control of alcohol sales—have had an impact on underage drinking and driving fatal crashes using annual state-level data, and compared states with strong laws to those with weak laws to examine their effect on beer consumption and fatal crash ratios.

Methods: Using the Fatality Analysis Reporting System, we calculated the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes as our key outcome measure. We used structural equation modeling to evaluate the three MLDA-21 laws. We controlled for covariates known to impact fatal crashes including: 17 additional MLDA-21 laws; administrative license revocation; blood alcohol concentration limits of.08 and.10 for driving; seat belt laws; sobriety checkpoint frequency; unemployment rates; and vehicle miles traveled. Outcome variables, in addition to the fatal crash ratios of drinking to nondrinking drivers under age 21 included state per capita beer consumption.

Results: Dram shop liability laws were associated with a 2.4% total effect decrease (direct effects: β =.019, p =.018). Similarly, RBS training laws were associated with a 3.6% total effect decrease (direct effect: β =.048, p =.001) in the ratio of drinking to nondrinking drivers under age 21 involved in fatal crashes. There was a significant relationship between dram shop liability law strength and per capita beer consumption, F (4, 1528) = 24.32, p <.001, partial η² =.016, showing states with strong dram shop liability laws (Mean (M) = 1.276) averaging significantly lower per capita beer consumption than states with weak laws (M = 1.340).

Conclusions: Dram shop liability laws and RBS laws were both associated with significantly reduced per capita beer consumption and fatal crash ratios. In practical terms, this means that dram shop liability laws are currently associated with saving an estimated 64 lives in the 45 jurisdictions that currently have the law. If the remaining 6 states adopted the dram shop law, an additional 9 lives could potentially be saved annually. Similarly, RBS training laws are associated with saving an estimated 83 lives in the 37 jurisdictions that currently have the laws. If the remaining 14 states adopted these RBS training laws, we estimate that an additional 28 lives could potentially be saved.