唐古特白刺单果优株果序性状变异研究

依据单果大小和口感等指标选择出39个唐古特白刺(Nitraria tangutorum Bobr．)果用优株。并以此为试验材料进一步就果序性状变异进行了研究,结果表明：白刺中选优株的果大小、果重、核果比等单果性状株间差异显著,而株内变异较小。在白刺天然群体内,果序性状差异极为显著,其中不乏果序重突出的单株。中选优株B12、B19等的平均果序重可达8．260g和8．271g,分别比对照高出6．86倍、6．87倍;比39个中选优株的平均值超出1．26倍、1．29倍。尽管白刺株内果序重变幅较大,但B12、B19的果序重最小值仍远远高出对照,甚至分别高出39株平均值79％和66％。由于与果序重密切相关的每序核果数与单果重等单果性状相对独立,因此从果用型白刺开发利用角度考虑,与产量相关更为紧密的果序重应该作为白刺优株选择以及亲本选择的主要依据。     

微囊藻和栅列藻光吸收特性的实验研究

在室内模拟槽中,以人工灯为光源,分别检测不同密度的微囊藻和栅列藻细胞悬液的光谱衰减,检测各样品的叶绿素含量和过滤后清液的溶解性有机碳(DOC)含量,并在紫外分光光度计上检测DOC光谱吸收,然后换算成吸收系数。再根据近似的线性加和关系计算出细胞悬液中各组分(藻细胞、水、DOC)的吸收系数。结果表明,微囊藻和栅列藻光衰减的波谱特征相似,在3个较高密度下的衰减系数的变化趋势相近,其衰减系数贡献率的平均值分别为84.95%和88.15%。将衰减系数除以各自的叶绿素浓度即可得到叶绿素的比吸收系数,两种藻3个较高密度的比吸收系数的平均值具有相似的波谱特征,在380～500、660～690nm两个波段有较明显的峰值,栅列藻和微囊藻在435nm的比吸收系数峰值分别为0.1118、0.0413(m2·mg-1chla),在670nm处的峰值分别为0.075、0.032(m2·mg-1chla)。但两者的比吸收系数差异较大,三个密度栅列藻在340～800nm的平均比吸收系数是0.0573(m2·mg-1chla),而微囊藻仅为0.0234(m2·mg-1chla),且微囊藻的所有波长的比吸收系数均小于栅列藻。根据这些参数来讨论两种藻类在分光衰减中的贡献率和光谱特征方面的差异及其生态学意义,以及在浮游植物的遥感监测方面的参考价值。     

卧龙自然保护区三江珙桐群落种间关系的数量分析

应用2×2列联表的Fisher精确检验、Pearson相关系数和Spearman秩相关系数检验研究了卧龙自然保护区三江珙桐(Davidia involucrata)群落种间关系。测定了83种植物,共3 403个种对的种间关联(或相关)。结果表明,2×2列联表的Fisher精确检验共186个种对为正关联,100个种对为负关联(P<0.05或P<0.01);Pearson相关系数有295个种对为正关联,129个种对为负关联;Spearman秩相关系数有448个种对为正关联,244个种对为负关联。用2×2列联表的Fisher精确检验不能反映两个种对的数量关系,应用Pearson相关系数和Spearman秩相关系数刻化种对间的数量变化关系;与Pearson相关系数检验相比,Spearman秩相关系数检验具有较高的灵敏度。种对的正关联和正相关,主要是由于它们具有相近的生物学特性,对生境具有相似的生态适应性和相互分离的生态位所致;而种对间的负关联和负相关,则主要是由于它们具有不同的生物学特性,对生境具有不同的生态适应性和相互重叠的生态位所致。     

旅游干扰对历山亚高山草甸优势种群种间相关性的影响

基于2×2列联表,应用方差比率法、χ2检验、Pearson相关系数检验及Spearm an秩相关系数检验等数量分析方法研究了旅游干扰对山西历山舜王坪亚高山草甸种间关联程度的影响。结果表明:(1)不同旅游距离带的联结指数(VR)均大于1,但统计量W均界于χ2分布的上下临界值之间。群落总体呈正关联,但联结性较弱,种的分布相对独立。(2)随着距游径距离的增加,4条不同旅游距离带的联结指数(VR)呈下降趋势;正负关联比有所增加,2χ检验显著率、Pearson相关检验显著率和Spearm an秩相关检验显著率都明显下降,说明旅游干扰对舜王坪亚高山草甸种间关联程度产生了一定的影响,距离游径越远,种间关联越趋于随机性,但这种影响尚未引起种间联结性的改变。(3)χ2检验与Pearson相关系数检验、Spearm an秩相关系数检验结果用来刻划种间相关性具有一定的相似之处,但仍存在一定差异,结合使用效果更好。与Pearson相关检验相比,Spearm an秩相关检验更具灵敏性。4)本研究结果支持随着群落演替进程的发展,群落种群总体向着无关联发展的观点。     

Using Standard Statistics to Consider Uncertainty in Industry-Based Life Cycle Inventory Databases (7 pp)

Goal, Scope and Background Decision-makers demand information about the range of possible outcomes of their actions. Therefore, for developing Life Cycle Assessment (LCA) as a decision-making tool, Life Cycle Inventory (LCI) databases should provide uncertainty information. Approaches for incorporating uncertainty should be selected properly contingent upon the characteristics of the LCI database. For example, in industry-based LCI databases where large amounts of up-to-date process data are collected, statistical methods might be useful for quantifying the uncertainties. However, in practice, there is still a lack of knowledge as to what statistical methods are most effective for obtaining the required parameters. Another concern from the industry's perspective is the confidentiality of the process data. The aim of this paper is to propose a procedure for incorporating uncertainty information with statistical methods in industry-based LCI databases, which at the same time preserves the confidentiality of individual data. Methods The proposed procedure for taking uncertainty in industry-based databases into account has two components: continuous probability distributions fitted to scattering unit process data, and rank order correlation coefficients between inventory flows. The type of probability distribution is selected using statistical methods such as goodness-of-fit statistics or experience based approaches. Parameters of probability distributions are estimated using maximum likelihood estimation. Rank order correlation coefficients are calculated for inventory items in order to preserve data interdependencies. Such probability distributions and rank order correlation coefficients may be used in Monte Carlo simulations in order to quantify uncertainties in LCA results as probability distribution. Results and Discussion A case study is performed on the technology selection of polyethylene terephthalate (PET) chemical recycling systems. Three processes are evaluated based on CO2 reduction compared to the conventional incineration technology. To illustrate the application of the proposed procedure, assumptions were made about the uncertainty of LCI flows. The application of the probability distributions and the rank order correlation coefficient is shown, and a sensitivity analysis is performed. A potential use of the results of the hypothetical case study is discussed. Conclusion and Outlook The case study illustrates how the uncertainty information in LCI databases may be used in LCA. Since the actual scattering unit process data were not available for the case study, the uncertainty distribution of the LCA result is hypothetical. However, the merit of adopting the proposed procedure has been illustrated: more informed decision-making becomes possible, basing the decisions on the significance of the LCA results. With this illustration, the authors hope to encourage both database developers and data suppliers to incorporate uncertainty information in LCI databases.     

Purification of lipase from Geotrichum candidum: conditions optimized for enzyme production using Box–Behnken design

The fungus Geotrichum candidum was selected from isolates of oil-mill waste as a potent lipase producer. Factors affecting lipase production by the fungus G. candidum in yeast-extract-peptone medium have been optimized by using a Box–Behnken design with seven variables to identify the significant correlation between effects of these variables in the production of the enzyme lipase. The experimental values were found to be in accordance with the predicted values, the correlation coefficient is 0.9957. It was observed that the variables days (6), pH (7.0), temperature (30 °C), carbon (1.25%), nitrogen (2.0%), Tween (1.0%) and salt concentrations (0.5 mM) were the optimum conditions for maximum lipase production (87.7 LU/ml). The enzyme was purified to homogeneity with an apparent molecular mass of 32 kDa by SDS-PAGE. The optimum pH at 40 °C was 7.0 and the optimum temperature at pH 7.0 was 40 °C. The enzyme was stable within a pH range of 6.5 to 8.5 at 30 °C for 24 h. The enzyme activity was strongly inhibited by AgNO₃, NiCl₂, HgCl₂, and EDTA. However, the presence of Ca²⁺ and Ba²⁺ ions enhanced the activity of the enzyme.     

间隔臂和探针长度与寡核苷酸芯片重复性相关性研究

研究寡核苷酸芯片的重复性与间隔臂（spacer）和探针长度之间的相关性。设计12条不同长度的带有不同spacer的探针,与749bp荧光标记靶序列杂交。扫描分析三次杂交结果,用Quantrray定量分析软件进行分析,随探针长度的延长,杂交信号的变异系数逐步降低,15mer的探针杂交的信号较弱,杂交不够稳定,重复性也相对较差,20mer、25mer、30mer的探针的变异系数逐渐降低。spacer为15时变异系数最小。说明选择spacer为poly（dT）15的25mer和30mer的探针可以获得较好的重复性。     

An assessment of a simple method for estimating the relative contributions of point and diffuse source phosphorus to in-river phosphorus loads

Implementation of the Urban Wastewater Treatment (UWWT) Directive requires a relatively simple methodology to partition in-river phosphorus (P) loads between diffuse and point sources in a catchment. In this study, standard monitoring data from the River Avon in Warwickshire, U.K. were used to estimate in-river loads. A novel aspect was the application of uncalibrated P run-off coefficients from the literature to areas of different land-use to estimate the diffuse P load. Point source P-loads were estimated either from monitoring data or from published export coefficient values. Analysis of the data showed that the main source of variability in the estimate of in-river loads was from the flow data, which, at many sites, did not cover a sufficient range of natural flow rates to allow reliable estimates of the annual load to be made. Analysis of data from 20 sites where this condition was fulfilled showed that, in the large, urbanised (15% land cover) River Avon catchment the use of uncalibrated run-off coefficients gave reliable estimates of diffuse loads.     

Ammonium adsorption in sediments of a tropical mangrove forest (Thailand) and a temperate Wadden Sea area (Denmark)

Dimensionless ammonium adsorption coefficients (K) were determined for tropical mangrove forest sediments and temperate Wadden Sea sediments. The K values were obtained from ammonium adsorption isotherms of KCl (2 M) extractable ammonium versus dissolved ammonium in the porewater; relationships that can be described by a linear model. Linearity was evident even at low porewater concentrations for mangrove sediment, according to isotherms based on KCl extractions on untreated sediment profiles. K-values were low in mangrove forest sediments (0.04–0.10), and higher in Wadden Sea sediments (0.17–1.12). The vertical range in K-values was larger at the vegetated sites, with highest values in subsurface sediments, which suggests differences in quantity and quality of the fine organic and inorganic fractions. The low ammonium adsorption in the mangrove sediments can be explained by a higher concentration of competitive cations, especially iron, in this iron-rich environment. The low adsorption of ammonium in mangrove sediments and vegetated surface sediment of the Wadden Sea was negatively related to the organic content of the sediments, which is in contrast to findings for other marine sediments. We suggest that organic material may have a diluting effect on the exchange capacity in fine-grained sediments, and that organic coatings may block ion exchange sites on clay surfaces. Thus, there may be a organic-rich ‘wetland’ versus organic-poor ‘sediment’ effect. This revised version was published online in July 2006 with corrections to the Cover Date.     

An indirect approach to the extensive calculation of relationship coefficients

A method was described for calculating population statistics on relationship coefficients without using corresponding individual data. It relied on the structure of the inverse of the numerator relationship matrix between individuals under investigation and ancestors. Computation times were observed on simulated populations and were compared to those incurred with a conventional direct approach. The indirect approach turned out to be very efficient for multiplying the relationship matrix corresponding to planned matings (full design) by any vector. Efficiency was generally still good or very good for calculating statistics on these simulated populations. An extreme implementation of the method is the calculation of inbreeding coefficients themselves. Relative performances of the indirect method were good except when many full-sibs during many generations existed in the population.