Biota: sediment partitioning of aluminium smelter related PAHs and pulp mill related diterpenes by intertidal clams at Kitimat, British Columbia

The question of polycyclic aromatic hydrocarbon (PAH) bioavailability and its relationship to specific PAH sources with different PAH binding characteristics is an important one, because bioavailability drives PAH accumulation in biota and ultimately the biochemical responses to the PAH contaminants. The industrial harbour at Kitimat (British Columbia, Canada) provides an ideal location to study the bioavailability and bioaccumulation of sediment hydrocarbons to low trophic level biota. Samples of soft shell clams (Mya arenaria) and intertidal sediment collected from multiple sites over six years at various distances from an aluminium smelter and a pulp and paper mill were analysed for 106 PAHs, plant diterpenes and other aromatic fraction hydrocarbons. Interpretation using PAH source ratios and multivariate data analysis reveals six principal hydrocarbon sources: PAHs in coke, pitch and emissions from anode combustion from the aluminium smelter, vascular plant terpenes and aromatised terpenes from the pulp and paper mill, petroleum PAHs from shipping and other anthropogenic activities and PAHs from natural plant detritus. Harbour sediments predominantly contain either pitch or pyrogenic PAHs from the smelter, while clams predominantly contain plant derived PAHs and diterpenes from the adjacent pulp mill. PAHs from the smelter have low bioavailability to clams (Biota-Sediment Accumulation Factors; BSAFs <1 for pitch and coke; <10 for anode combustion, decreasing to ∼0.1 for the mass 300 and 302 PAHs), possibly due to binding to pitch or soot carbon matrices. Decreases in PAH isomer ratios between sediments and clams likely reflect a combination of variation in uptake kinetics of petroleum PAHs and compound specific metabolism, with the importance of petroleum PAHs decreasing with increasing molecular weight. Plant derived compounds exhibit little natural bioaccumulation at reference sites, but unsaturated and aromatised diterpenes released from resins by industrial pulping processes are readily accumulated by the clams (BSAFs >500). Thus while most of the smelter associated PAHs in sediments may not be bioavailable to benthic organisms, the plant terpenes (including retene, totarol, ferruginol, manool, dehydroabietane and other plant terpenes that form the chemical defence mechanism of conifers) released by pulp mills are bioavailable and possess demonstrated toxic properties. The large scale release of plant terpenes by some of the many pulp mills located in British Columbia and elsewhere represents a largely undocumented risk to aquatic biota.     

Wave refraction–diffraction effect in the wind wave model WWM

Based on the extended mild-slope equation, the wind wave model (WWM; Hsu et al., 2005) is modified to account for wave refraction, diffraction and reflection for wind waves propagating over a rapidly varying seabed in the presence of current. The combined effect of the higher-order bottom effect terms is incorporated into the wave action balance equation through the correction of the wavenumber and propagation velocities using a refraction–diffraction correction parameter. The relative importance of additional terms including higher-order bottom components, the wave–bottom interaction source term and wave–current interaction that influence the refraction–diffraction correction parameter is discussed. The applicability of the proposed model to calculate a wave transformation over an elliptic shoal, a series of parallel submerged breakwater induced Bragg scattering and wave–current interaction is evaluated. Numerical results show that the present model provides better predictions of the wave amplitude as compared with the phase-decoupled model of Holthuijsen et al. (2003).     

长肋日月贝的营养成分分析及评价

对野生长肋日月贝(Amusium pleuronectes)的闭壳肌和贝肉其他部分的基本营养成分进行分析.结果表明:闭壳肌的平均质量分数为18.13%±2.15%,超过优良养殖海湾扇贝"中科红".闭壳肌的蛋白质质量比(干质量)为847.62 g/kg,贝肉其他部分蛋白质质量比为662.50 g/kg.必需氨基酸与非必需...     

数据分发服务在分布式嵌入式系统中的研究与设计

分布式系统越来越广泛地应用于嵌入式设备,尤其是在航空航天事业、交通控制等方面。而这些应用场合嵌入式系统的体系结构呈现以网络为中心的趋势,这便对通信的实时性、动态灵活性提出更高要求,同时要求分布式嵌入式系统各参与者之间采用一种具有松散耦合特性和灵活的通信模式和交互机制。针对此问题,介绍RTI公司推出的一套支持出版/订阅设计思想的应用程序接口;同时设计并搭建了一个解决此分布异构问题的平台,该平台为应用程序设计人员提供了一个更高层次的设计空间,允许应用程序的程序员通过即插即用组件的方式编程完成各个参与者相互间的通讯;而且整个系统的设计更满足高效和实时性的要求。     

日照茶叶生产基地绿茶品质评价分析

研究了日照茶叶生产基地BDC,BBSZ和BYQ3个茶园的福鼎大白、黄山群体和鸠坑3个绿茶品种主要生化成分的含量,并将其与浙江龙井、福建乌龙茶名种等南方优质绿茶的各生化成分进行对比分析。结果表明,3个绿茶品种中,鸠坑的品质最好,福鼎大白次之,黄山群体最差,但日照绿茶总体品质要．优于各南方绿茶。     

基于Facade模式的大规模组件切换策略

提出一种基于Facade设计模式的大规模组件切换策略,对策略的整体框架和其中的Facade核心模块进行了详细阐述.该策略的使用将使开发人员不必关注于实现各组件之间的复杂调用关系,而把主要精力放在各独立组件和Facade 核心模块的设计与实现上.     

水溶液中各化学组分可能存在式形分配及Eh值的计算方法

本文在参阅Crerar D.A.等人的资料的基础上,比较系统地论述了水溶液中各种化学组分可能存在形式分配及Eh值的计算方法。文章从对施实计算所需的原始数据的说明开始,主要从以下几个方面说明了计算方法:1.热力学问题的数学描述;2.问题的数值解;3.活度系数的校正;4.迭代步骤;5.Eh值的计算。文中以华清池温泉水化学分析资料为例,分别给出了此资料在12℃和42℃时的计算结果。由于分析技术和计算方法的误差,Eh值的计算结果存在一定的偏离,这也可能是由于给定温度下水中某些组分间存在着非平衡而引起的。     

Linux嵌入式系统根文件系统的选择与制作

Linux操作系统做为嵌入式系统近年应用越来越广泛，Linux根文件系的装载是Linux内核启动期间进行的最后操作之一，它是Linux嵌入式系统的一个重要组成部分，系统地分析了Linux嵌入式系统根文件系统的类型，内容选择以及制作方法。     

基于Qtopia的中文输入法设计与实现

基于嵌入式Linux系统上广泛使用的GUI应用程序开发包Qtopia,利用Qtopia所提供的插件技术,给出在嵌入式Linux系统中中文输入法的整体设计框架,并以拼音输入法为例介绍其实现过程.     

A case study in catchment hydrochemistry: Conflicting interpretations from hydrological and chemical observations

Soil water, stream water, groundwater and rain water were sampled through a storm event in a moorland catchment. Samples were analysed for major ions and deuterium. Chloride and deuterium are used as tracers to enable separation of the stream runoff hydrograph into three components: rain, soil and groundwater. The results indicate that rain water arrives in the stream quickly during the event and contributes a significant volume to the runoff peak. The chemical signal in the rain water is, however, significantly damped, apparently due to mixing with soil water held in the catchment before the event. This is further modified before reaching the stream, apparently through mixing with a deeper groundwater component. Interpretation of tracer, chemistry and hydrological data to present an integrated picture of catchment hydrochemical response is difficult due to problems in the chemical and conceptual definition of the flow components.